FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Markovic, N Gasteiger, H Ross, PN AF Markovic, N Gasteiger, H Ross, PN TI Kinetics of oxygen reduction on Pt(hkl) electrodes: Implications for the crystallite size effect with supported Pt electrocatalysts SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID TRANSFORM INFRARED-SPECTROSCOPY; FUEL-CELL ELECTROLYTE; TETRAFLUOROETHANE-1,2-DISULFONIC ACID; SULFURIC-ACID; PLATINUM; ADSORPTION; CARBON; SURFACES; PT(111); PT(100) AB The kinetics of the oxygen reduction reaction (ORR) on Pt(hkl) surfaces is found to vary with crystal face in a different manner depending on the electrolyte. In perchloric acid, the variation in activity at 0.8 to 0.9 V is relatively small between the three low index faces, with activity increasing in the order (100) < (110) approximate to (111). A similar structure sensitivity was observed in KOH, increasing in the order (100) < (110) < (111), but with larger differences. In sulfuric acid, the variations in activity with crystal fate were much larger, with the difference between the most active and the least active being about two orders of magnitude, and increased in the opposite order (111) << (100) < (110). The variations in activity with crystal face in perchloric acid and KOH arise from the structure sensitive inhibiting effect of OHads i.e., a strongly inhibiting effect on (100) and smaller effects on (110) and (111). The variations in activity with crystal face in sulfuric acid arise from highly structure specific adsorption of sulfate/bisulfate anions in this electrolyte, which has a strongly inhibiting effect on the (111) surface. The crystallite size effect for the ORR reported for supported Pt catalysts in sulfuric acid at ambient temperature is fully explained by applying our single crystal results to classical models of the variation in particle shape with size. RP Markovic, N (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 25 TC 300 Z9 308 U1 15 U2 151 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP 1591 EP 1597 DI 10.1149/1.1837646 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600025 ER PT J AU Mo, YB Hu, YN Bae, IT Miller, B Antonio, MR Scherson, DA AF Mo, YB Hu, YN Bae, IT Miller, B Antonio, MR Scherson, DA TI In site x-ray absorption fine structure studies of a manganese dioxide electrode in a rechargeable MnO2/Zn alkaline battery environment SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID XANES SPECTROSCOPY; HYDROUS OXIDES; EXAFS; FE; GAMMA-MNO2; MN; INFORMATION; CHEMISTRY; CO; NI AB Electronic and structural aspects of a MnO2 electrode in a rechargeable MnO2/Zn battery environment have been investigated by in situ Mn K-edge x-ray absorption fine structure (XAFS). The relative amplitudes of the three major Fourier transform shells of the extended. XAFS function of the rechargeable MnO2 electrode in the undischarged state were similar to those found for ramsdellite, a MnO2 polymorph with substantial corner-sharing linkages among the basic MnO6 octahedral units. The analyses of the background-subtracted pre-edge peaks and absorption edge regions for the nominally l-e(-) discharged electrode were consistent with Mn3+ as being the predominant constituent species, rather than a mixture of Mn4+ and Mn2+ sites. Furthermore, careful inspection of both the x-ray absorption near edge structure and EXAFS indicated that the full recharge of NnO(2), which had been previously discharged either by one or two equivalent electrons, generates a material with decreased corner-sharing linkages compared to the original undischarged MnO2. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. RP Mo, YB (reprint author), CASE WESTERN RESERVE UNIV,DEPT CHEM,CLEVELAND,OH 44106, USA. NR 26 TC 8 Z9 9 U1 1 U2 17 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP 1598 EP 1603 DI 10.1149/1.1837647 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600026 ER PT J AU Zhang, JG McGraw, JM Turner, J Ginley, D AF Zhang, JG McGraw, JM Turner, J Ginley, D TI Charging capacity and cycling stability of VOx films prepared by pulsed laser deposition SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ELECTRODES; LITHIUM; BATTERIES; INTERCALATION AB The lithium ion charging capacity and cycling stability of vanadium oxide thin-films prepared by pulsed laser deposition (PLD) are reported. PLD films were prepared at various temperatures and atmospheres from a V6O13 target. The charging capacity of these films depended strongly on the substrate deposition temperature and atmosphere. The best crystalline films were grown at 200 degrees C. Crystalline oriented V2O5 films were prepared by PLD at 200 degrees C in an oxygen environment. These films can be cycled in the voltage range between 4.1 and 2.0 V for more than 100 cycles with very little capacity loss. The specific charge capacity of the films was 340 Ah/kg when the discharge current density was 0.1 mA/cm(2), which corresponds to 1.2 lithium atoms per vanadium atom. The capacity increased to 1.5 lithium atoms per vanadium atom when cycled at a current density of 0.02 mA/cm(2). Amorphous vanadium oxide films with similar specific capacities were prepared by PLD in vacuum at 200 degrees C. The capacity loss in these films was less than 2% after 100 cycles. Although thermally evaporated vanadium oxide films had similar initial capacities under the same charging conditions, they lost more than 17% of their charging capacity after 100 cycles. The improved cycle stability in the amorphous vanadium oxide films may be partially attributed to the improved surface morphology of the PLD films. RP Zhang, JG (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. NR 19 TC 92 Z9 97 U1 1 U2 29 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP 1630 EP 1634 DI 10.1149/1.1837652 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600031 ER PT J AU Striebel, KA Wen, SJ Ghantous, DI Cairns, EJ AF Striebel, KA Wen, SJ Ghantous, DI Cairns, EJ TI Novel nanodisperse composite cathode for rechargeable lithium/polymer batteries SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID SPINEL ELECTRODES; LITHIUM; SYSTEM AB A novel approach to the design of a composite positive electrode for lithium/polymer cells based on a polyethylene oxide (PEG) polymer, manganese (II), and lithium hydroxide has been discovered. A chemical reaction leading to a stable suspension occurs when the precursor salts are added directly: to a polymer solution. The electrode film is cast directly and then vacuum-dried with no calcination step. The film is amorphous as-prepared and has been named the nanodisperse composite cathode. or NCC. Film characterization with x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy indicates that the Mn (II) has been oxidized to Mn (IV), which forms a complex with the PEG. This leads to highly disperse Mn sites within the polymer matrix and highly mobile Li ions within the PEO. Cells have been assembled with NCC films, PEO-LiN(SO2CF3)(2) electrolyte and lithium metal, and cycled at 85 to 105 degrees C at current densities of 0.2 mA/cm(2) between the voltage limits of 3.5 and 2.0 V. Discharge capacities as high as 340 mAh/g-cathode film have been achieved on the First half-cycle. The discharge capacity declines consistently during a formation process to steady values as high as 50 mAh/g-cathode. This cathode capacity is equivalent to an active material capacity of 150 mAh/g in a composite cathode at a loading of 30 weight percent. The synthesis process for the NCC is simple, should be relatively easy to scale up, and should lead to an extremely useful composite cathode for a Lithium polymer battery. RP Striebel, KA (reprint author), ERNEST ORLANDO LAWRENCE BERKELEY NATL LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720, USA. RI Cairns, Elton/E-8873-2012 OI Cairns, Elton/0000-0002-1179-7591 NR 11 TC 5 Z9 7 U1 0 U2 5 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP 1680 EP 1685 DI 10.1149/1.1837659 PG 6 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600038 ER PT J AU Nguyen, T Hsu, ST Nguyen, TD AF Nguyen, T Hsu, ST Nguyen, TD TI Diffusion-induced precipitation model of arsenic in arsenosilicate glass SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article AB A model for the precipitation of arsenic in arsenosilicate glass (AsSG) is developed to simulate the increased arsenic concentration at the glass/silicon interface after high temperature heat-treatment. In this model, the precipitation occurs at the interface when arsenic concentration exceeds the solubility limit and grows laterally until it covers the entire interface. This assumption is partly supported by secondary ion mass spectrometry and transmission electron microscopy results showing the presence of silicon arsenide precipitates near the interface. Reasonable agreement with published experimental data is achieved. This model can be used to predict the precipitation, and thereby develop novel techniques to avoid precipitate formation, and to optimize the material developments. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720. RP Nguyen, T (reprint author), SHARP MICROELECT TECHNOL INC,CAMAS,WA 98607, USA. NR 11 TC 4 Z9 4 U1 0 U2 0 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP 1785 EP 1789 DI 10.1149/1.1837680 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600059 ER PT J AU Thackeray, MM AF Thackeray, MM TI A comment on the structure of thin-film LiMn2O4 electrodes SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID LITHIUM CELLS; SPINEL; ELECTROCHEMISTRY; BATTERIES; OXIDES AB Thin-film LiMn2O4 electrodes that are deposited either by electron-beam evaporation or radio-frequency sputtering show electrochemical activity between 4 and 5 V vs. metallic lithium. This behavior is significantly different to that expected from a standard Li[Mn-2]O-4 spinel electrode. The unusual electrochemical behavior of thin-film LiMn2O4 electrodes can be accounted for in terms of a structural model that may be considered as an intergrowth of two spinels, Li-8a[Mn-2](16d)O-4 and Li-8b[Mn-2](16c)O-4, where 8a and 8b refer to tetrahedral sites, and 16c and 16d refer to octahedral sites of the space group Fd3m. RP Thackeray, MM (reprint author), ARGONNE NATL LAB, ELECTROCHEM TECHNOL PROGRAM, DIV CHEM TECHNOL, ARGONNE, IL 60439 USA. NR 23 TC 34 Z9 35 U1 2 U2 14 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD MAY PY 1997 VL 144 IS 5 BP L100 EP L102 DI 10.1149/1.1837624 PG 3 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA XD006 UT WOS:A1997XD00600003 ER PT J AU Shore, BW Perry, MD Britten, JA Boyd, RD Feit, MD Nguyen, HT Chow, R Loomis, GE Li, LF AF Shore, BW Perry, MD Britten, JA Boyd, RD Feit, MD Nguyen, HT Chow, R Loomis, GE Li, LF TI Design of high-efficiency dielectric reflection gratings SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Review ID CHIRPED-PULSE AMPLIFICATION; SURFACE-RELIEF GRATINGS; COUPLED-WAVE ANALYSIS; METALLIC DIFFRACTION GRATINGS; GROUP-VELOCITY DISPERSION; MULTILAYER GRATINGS; ARBITRARY PROFILES; CONICAL MOUNTINGS; INTEGRAL THEORY; THICK GRATINGS AB We discuss examples of designs for all-dielectric reflection gratings that tolerate high intensity and are potentially capable of placing up to 99% of the incident light into a single diffraction order, such as are needed for contemporary high-power lasers utilizing chirped-pulse amplification. The designs are based on placing a dielectric transmission grating atop a high-reflectivity (HR) multilayer dielectric stack. We comment on the connection between transmission gratings and reflection gratings and note that the grating and the HR stack can, to a degree, be treated independently. Because many combinations of gratings and multilayer stacks offer high efficiency, it is possible to attain secondary objectives in the design. We describe examples of such designs aimed toward improving fabrication and lowering the susceptibility to laser-induced damage. We present examples of the dependence of grating efficiency on grating characteristics. We describe examples of high-efficiency (95%) gratings that we have fabricated by using hafnia and silica multilayers. (C) 1997 Optical Society of America. C1 UNIV ARIZONA,CTR OPT SCI,TUCSON,AZ 85721. RP Shore, BW (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. RI Feit, Michael/A-4480-2009 NR 101 TC 110 Z9 128 U1 5 U2 49 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD MAY PY 1997 VL 14 IS 5 BP 1124 EP 1136 DI 10.1364/JOSAA.14.001124 PG 13 WC Optics SC Optics GA WV712 UT WOS:A1997WV71200019 ER PT J AU Nanba, T Nodake, Y Muneyasu, M Williams, GP Hayashi, S AF Nanba, T Nodake, Y Muneyasu, M Williams, GP Hayashi, S TI Size-dependence of phase transition of CdS microcrystals SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article DE far-infrared transmission spectrum under high pressure; CdS microcrystal; structural phase transition; surface phonon absorption ID TRANSFORMATION; NANOCRYSTALS; ABSORPTION; WURTZITE; PRESSURE AB We present experimental evidence which shows that the critical pressure (P-c) of the structural phase transition in CdS microcrystals under pressure differs from that of the bulk state and also that its magnitude depends on the microcrystal size. Far-infrared transmission measurements on CdS microcrystals of various sizes were carried out at pressure up to 8.3 GPa at room temperature by using synchrotron light source. The surface phonon at around 268 cm(-1) at P=0 (atmosphere pressure) showed a blue shift with pressure. With further increase in pressure, the surface phonon showed a sudden decrease in energy. The very broad absorption band was found at the high pressure phase after the structural phase transition. Particle with smaller diameters was found to show higher P-c values. The origin of the increase in the P-c value is discussed related to thermodynamics and a surface tension of microcrystal. C1 BROOKHAVEN NATL LAB, NATL SYNCHROTRON LIGHT SOURCE DEPT, UPTON, NY 11973 USA. KOBE UNIV, FAC ENGN, DEPT ELECT & ELECT ENGN, KOBE, HYOGO 657, JAPAN. RP KOBE UNIV, FAC SCI, DEPT PHYS, KOBE, HYOGO 657, JAPAN. NR 22 TC 2 Z9 2 U1 3 U2 5 PU PHYSICAL SOC JAPAN PI TOKYO PA YUSHIMA URBAN BUILDING 5F, 2-31-22 YUSHIMA, BUNKYO-KU, TOKYO, 113-0034, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD MAY PY 1997 VL 66 IS 5 BP 1526 EP 1531 DI 10.1143/JPSJ.66.1526 PG 6 WC Physics, Multidisciplinary SC Physics GA XB379 UT WOS:A1997XB37900050 ER PT J AU Malyshev, MV Donnelly, VM AF Malyshev, MV Donnelly, VM TI Determination of electron temperatures in plasmas by multiple rare gas optical emission, and implications for advanced actinometry SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID INDUCED THERMAL-DESORPTION; CYCLOTRON-RESONANCE PLASMA; EXCITATION CROSS-SECTIONS; HIGH-DENSITY PLASMAS; IMPACT EXCITATION; IN-SITU; CHEMICAL TOPOGRAPHY; METASTABLE STATES; HELIUM-ATOMS; ARGON AB A method is described for determining the electron temperature of a low pressure plasma of the type used in microelectronics materials processing. A small amount of an equal mixture of He, Ne, Ar, Kr, and Xe is added to the process gas (in this example Cl-2) and the intensities of optical emission lines from the Paschen 2p levels of the rare gases are recorded. The observed emission intensities are compared with those computed from a model that includes electron impact excitation from the ground state, as well as two-step electron impact excitation through intermediate metastable levels. This latter route is shown to be the dominant one for nearly half of the levels. Using adjusted, published electron impact excitation cross sections and assuming a Maxwellian electron energy distribution, the electron temperature (T-e), the only adjustable parameter, was determined from the best match between the observed and computed intensities. For a high density, helical resonator Cl-2 plasma at 10 mTorr, T-e = 2.2+/-0.5 eV was determined from this method. This value is about 1 eV lower than the typical values reported for high density inductively coupled Cl-2 plasmas at similar pressures. While the precision of the method is expected to be high, the accuracy of T-e determined from optical emission would likely be improved with more accurate cross section data. Implications for actinometric determination of species concentrations in plasmas are also discussed. (C) 1997 American Vacuum Society. C1 PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, PRINCETON, NJ 08543 USA. RP Malyshev, MV (reprint author), AT&T BELL LABS, LUCENT TECHNOL, MURRAY HILL, NJ 07974 USA. NR 59 TC 113 Z9 113 U1 0 U2 10 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 EI 1520-8559 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD MAY-JUN PY 1997 VL 15 IS 3 BP 550 EP 558 DI 10.1116/1.580682 PN 1 PG 9 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100018 ER PT J AU Hong, J Lee, JW Vartuli, CB Abernathy, CR MacKenzie, JD Donovan, SM Pearton, SJ Zolper, JC AF Hong, J Lee, JW Vartuli, CB Abernathy, CR MacKenzie, JD Donovan, SM Pearton, SJ Zolper, JC TI Rapid thermal processing of ill-nitrides SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID MOLECULAR-BEAM EPITAXY; ION-IMPLANTED GAAS; GROWTH; OVERPRESSURE; INP AB High-temperature annealing is necessary in a number of applications for m-nitrides, including activation of Si+ or Mg+ implants for doping, maximization of implant-isolated regions, and Ohmic contact sintering. We have compared two methods for protection against surface dissociation of GaN, AlN, InN, InxGa1-xN, and InxAl1-xN during rapid thermal processing in N-2 ambients. In the first method, AlN or InN powder is placed in the reservoirs of a SiC-coated graphite susceptor and provides a N-2 overpressure for the nitride samples within the susceptor. In the second method, the nitrides are placed face down on other III-V substrates during annealing. In both techniques N loss from the nitride surface is found to occur at greater than or equal to 1050 degrees C for GaN and greater than or equal to 1100 degrees C for AlN and greater than or equal to InN, as measured by Auger electron spectroscopy. Real surface roughening is generally significant only for the In-containing materials, with GaN and AlN retaining smooth morphologies even up to 1150 degrees C unless H-2 is present in the annealing ambient. When InN powder is used in the susceptor, there is In droplet condensation on the surfaces of all samples above similar to 750 degrees C leading to higher root-mean-square surface roughness measured by atomic force microscopy. The N-2-deficient surfaces of the binary nitrides become strongly n type, while those of ternaries become less conducting. At temperature of 850-900 degrees C, the In droplets on thermally degraded ternaries also begin to evaporate, leading to an apparent improvement in morphology. The presence of H-2 or O-2 in the annealing ambient lowers the dissociation temperature of each of the nitrides by 100-200 degrees C, due to an enhancement in N-2 removal. (C) 1997 American Vacuum Society. C1 UNIV FLORIDA, DEPT MAT SCI & ENGN, GAINESVILLE, FL 32611 USA. SANDIA NATL LABS, ALBUQUERQUE, NM 87185 USA. NR 25 TC 10 Z9 10 U1 3 U2 10 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 EI 1520-8559 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD MAY-JUN PY 1997 VL 15 IS 3 BP 797 EP 801 DI 10.1116/1.580710 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100064 ER PT J AU Overbury, SH Huntley, DR Mullins, DR Ailey, KS Radulovic, PV AF Overbury, SH Huntley, DR Mullins, DR Ailey, KS Radulovic, PV TI Surface studies of model supported catalysts: NO adsorption on Rh/CeO2(001) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID X-RAY PHOTOELECTRON; REDUCTION; RH(111); OXYGEN; CERIA; CEO2; CO AB The adsorption and reaction of NO on a model catalyst composed of Rh supported on ceria has been studied. CeO2 films were grown epitaxially by laser ablation onto SrTiO3(001) substrates. X-ray diffraction and transmission electron microscopy indicate the films are single crystalline with (001) orientation. Comparison of experimental and computer simulated ion scattering distributions indicate that an annealed CeO2 surface is well ordered and is composed of both O and Ce terminated domains. Exposures to CO and H-2 at various temperatures had little or no effect upon the ceria. Photoemission from the Ce 4d levels exhibits complex features that differ between a sputtered and a fully oxidized surface. NO does not adsorb on the Rh free, fully oxidized surface, but does adsorb upon a sputter reduced surface. The thermally induced conversion from molecular NO to atomic N was measured by both N Is photoemission and x-ray absorption as a function of Rh coverage to determine substrate effects on Rh surface chemistry. Rh deposited on sputtered ceria is more active for NO decomposition and yields higher N-2 desorption temperatures than does Rh on the fully oxidized support. (C) 1997 American Vacuum Society. RP OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 15 TC 43 Z9 44 U1 2 U2 19 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 EI 1520-8559 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD MAY-JUN PY 1997 VL 15 IS 3 BP 1647 EP 1652 DI 10.1116/1.580647 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200098 ER PT J AU Herdt, GC Czanderna, AW AF Herdt, GC Czanderna, AW TI Metal overlayers on organic functional groups of self-organized molecular assemblies .7. Ion scattering spectroscopy and x-ray photoelectron spectroscopy of Cu/CH3 and Cu/COOCH3 SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID INTERFACES; SURFACES; ADHESION; ACID; GOLD AB X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) were used to characterize octadecanethiol [ODT, HS(CH2)(17)CH3] and methylmercaptohexadecanoate [MMHD, HS(CH2)(15)COOCH3] self-assembled monolayers (SAMs) before and after depositing up to 1.0 nm Cu at ca. 10(-7) Torr. Results from XPS O Is, Cu 2p, and C Is spectra do not indicate that a complex is formed (no chemical shifts) between Cu and the COOCH3 of MMHD or ODT organic functional groups (OFG) at 295 K. Although no direct evidence for Cu/COOCH3 interactions is evident, the initial value for ISS Cu peak intensities for 1.0 nm of Cu on COOCH3 of MMHD requires 7 h before it disappears compared with less than 150 min for Cu on CH3 of ODT. These times are also bracketed from XPS results. which are less sensitive than ISS to loss of copper from the M/SAM surface. The longer penetration time through MMHD versus ODT might be explained by weak interactions between Cu and COOCH3 of MMHD by different defect densities in the SAMs. The actual Cu deposition versus a layer-by-layer growth model and narrowing of the XPS Cu 2p peaks both provide support for formation of Cu clusters on the OFGs prior to penetration to the SAM/Au interface. (C) 1997 American Vacuum Society. C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. NR 28 TC 17 Z9 17 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 513 EP 519 DI 10.1116/1.580882 PN 1 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100012 ER PT J AU Hudson, ML Bartel, TJ AF Hudson, ML Bartel, TJ TI Direct simulation Monte Carlo computation of reactor-feature scale flows SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc AB The direct simulation Monte Carlo (DSMC) technique was used to model the flow around multiple features on a wafer. Since the DSMC technique is valid in both the continuum and rarefied flow regimes, the near-surface reactor flow was directly coupled with the features into a single reactor-feature scale model. This model was then used to determine the effects of operating conditions, feature geometry, and surface chemistry on the concentrations and fluxes to a hat and featured surface. The surface chemistry addressed both chlorine etching of aluminum and SiO2 deposition from a silane/oxygen/argon gas mixture. For both the etch and deposition cases, the concentration of products was higher near the featured surface than the flat surface. This was partially due to multiple molecular reflections between the horizontal and vertical surfaces of the features. While the reacting area of the features was greater than the flat surface with no features, the fluxes to the features were less due to the direction of the incoming flow. Thus, topography models using fluxes to flat surfaces, which are assumed in full reactor scale models, will overpredict deposition or etch rates. A simplified adjustment to the flat surface flux was made to obtain more accurate boundary conditions for topography models and thus, better predictions of deposition and etch rates. (C) 1997 American Vacuum Society. RP Hudson, ML (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 7 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 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 559 EP 563 DI 10.1116/1.580683 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100019 ER PT J AU Shul, RJ McClellan, GB Briggs, RD Rieger, DJ Pearton, SJ Abernathy, CR Lee, JW Constantine, C Barratt, C AF Shul, RJ McClellan, GB Briggs, RD Rieger, DJ Pearton, SJ Abernathy, CR Lee, JW Constantine, C Barratt, C TI High-density plasma etching of compound semiconductors SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID ELECTRON-CYCLOTRON-RESONANCE; GAAS; INP; DISCHARGES; DAMAGE; GASB AB Inductively coupled plasma (ICP) etching of GaAs, GaP, and InP is reported as a function of plasma chemistry, chamber pressure, rf power, and source power. Etches were characterized in terms of rate and anisotropy using scanning electron microscopy, and root-mean-square surface roughness using atomic force microscopy. ICP etch rates were compared to electron cyclotron resonance etch rates for Cl-2/Ar, Cl-2/N-2, BCl3/Ar, and BCl3/N-2 plasmas under similar plasma conditions. High GaAs and GaP etch rates (exceeding 1500 nm/min) were obtained in Cl-2-based plasmas due to the high concentration of reactive Cl neutrals and ions generated as compared to BCl3-based plasmas. InP etch rates were much slower and independent of plasma chemistry due to the low volatility of the InClx etch products. The surface morphology for all three materials was smooth over a wide range of etch conditions. (C) 1997 American Vacuum Society. C1 UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611. PLASMA THERM INC,ST PETERSBURG,FL 33716. RP Shul, RJ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 18 TC 95 Z9 96 U1 0 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 633 EP 637 DI 10.1116/1.580696 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100032 ER PT J AU Vartuli, CB Pearton, SJ Lee, JW Mackenzie, JD Abernathy, CR Shul, RJ AF Vartuli, CB Pearton, SJ Lee, JW Mackenzie, JD Abernathy, CR Shul, RJ TI Plasma etching of III-nitrides in ICl/Ar and IBr/Ar plasmas SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID MOLECULAR-BEAM EPITAXY; GAN; GAAS; INN; GROWTH; CH3I; ALN AB Two new plasma chemistries, ICl/Ar and IBr/Ar, were investigated for dry etching of III-nitrides. Under electron cyclotron resonance conditions, we examined the effect of plasma composition, and source and chuck power on etch rates and surface morphology. The etch rate of InN proved to be the most sensitive of the materials investigated to the plasma composition and ion density in ICl plasmas. The GaN, InN, and InGaN etch rates reached similar to 13000, 11500, and 7000 Angstrom/min, respectively, at 250 W rf chuck power and 1000 W microwave source power for ICl discharges. The etch rates in IBr plasmas were somewhat slower than in ICI. The etched surface of GaN was found to be smooth, with no significant preferential loss of N from the surface at low rf powers in either chemistry. There was no significant residue on the GaN surfaces after etching in IBr/Ar, and only slight chlorine contamination on the surfaces etched in ICl/Ar. Selectivities of 5-10 for GaN over InN, AIN, or InAIN were achieved in ICl/Ar, but were < 4 under all conditions with IBr/Ar. (C) 1997 American Vacuum Society. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Vartuli, CB (reprint author), UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611, USA. NR 20 TC 8 Z9 8 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 638 EP 642 DI 10.1116/1.580697 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100033 ER PT J AU Holtrop, KL Jackson, GL Kellman, AG Lee, RL West, WP Wood, RD Whyte, DG AF Holtrop, KL Jackson, GL Kellman, AG Lee, RL West, WP Wood, RD Whyte, DG TI Characterization of wall conditions in DIII-D SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID BORONIZATION AB Wall conditioning in DIII-D is one of the most important factors in achieving reproducible high confinement discharges. For example, the very high confinement mode (VH-mode) was only discovered after boronization, a chemical vapor deposition technique to deposit a thin boron film over the entire surface of the tokamak. In order to evaluate wall conditions and provide a data base to correlate these wall conditions with tokamak discharge performance, a series of nominally identical reference VH-mode discharges (1.6 MA, 2.1 T, double null diverted) were taken at various times during a series of experimental campaigns with evolving wall conditions. These reference discharges have allowed a quantitative determination of how the wall conditions have evolved. For instance, core carbon and oxygen levels in the VH-mode phase remained at historically low levels during the 1995 run year and there was also a steady decrease in the oxygen levels at plasma initiation during this period. We will discuss the long term changes in low Z impurities and the effect of wall conditioning techniques such as boronization and baking on these impurities. In addition, the evolution of the deuterium recycling rates will be discussed. (C) 1997 American Vacuum Society. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. RP Holtrop, KL (reprint author), GEN ATOM CO,SAN DIEGO,CA 92186, USA. NR 11 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 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 678 EP 682 DI 10.1116/1.580800 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100041 ER PT J AU Foerster, CL Lanni, C Lee, R Mitchell, G Quade, W AF Foerster, CL Lanni, C Lee, R Mitchell, G Quade, W TI Tests of an environmental and personnel safe cleaning process for Brookhaven National Laboratory accelerator and storage ring components SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID PLATED BEAM TUBES; STAINLESS; ALUMINUM; COPPER AB A large measure of the successful operation of the National Synchrotron Light Source (NSLS) al Brookhaven National Laboratory (BNL) for over a decade can be attributed to the cleaning of its ultrahigh vacuum (UHV) components during and after construction. A new UHV cleaning process, which has to be environmentally and personnel safe, is needed to replace the harsh, unfriendly process which is still in use. Dow Advanced Cleaning Systems was contracted to develop a replacement process without the use of harsh chemicals and which must clean vacuum surfaces as well as the existing process. Acceptance of the replacement process was primarily based on photon stimulated desorption (PSD) measurements of beam tube samples run on NSLS beam line U1OB. One meter long beam tube samples were fabricated from aluminum, 304 stainless steel, and oxygen-free copper. Initially, coupon samples were cleaned and passed preliminary testing for the proposed process. Next, beam tube samples of each material were cleaned, and the PSD measured on beam line U10B using white light with a critical energy of 487 eV. Prior to cleaning, the samples were contaminated with a mixture of cutting oils, lubricants, vacuum oils, and vacuum grease. The contaminated samples were then baked. Samples of each material were also cleaned with the existing process after the same preparation Beam tube samples were exposed to between 10(22) and 10(23) photons per meter for a PSD measurement. Desorption yields for H-2, CO, CO2, CH4, and H2O are reported for both the existing cleaning and for the replacement cleaning process. Preliminary data, residual gas scans, and PSD results are given and discussed. The new process is also compared with new cleaning methods developed in other laboratories. After modification, the new UHV cleaning process was accepted by BNL. C1 DOW CHEM CO USA,ADV CLEANING SYST,MIDLAND,MI 48674. RP Foerster, CL (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 11 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 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 731 EP 735 DI 10.1116/1.580811 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100052 ER PT J AU Johnson, ML Manos, DM Provost, T AF Johnson, ML Manos, DM Provost, T TI Gas permeation and leakage through reusable seals SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc AB This article describes a study of outgassing and permeation of high vacuum seal materials for use in multichamber deposition tools and other production tools to make electronic materials and devices. The study compares the performance between all metal, single use seals (copper knife edge and aluminum spring-loaded seals), elastomer O-rings, and a ''compound seal.'' The compound seal consists of an outer baked elastomer O-ring surrounding an inner compressible aluminum seal with rough pumping (40 mTorr) on the interspace. Conceptually, this seal should perform like an elastomer because of its ability to seal repeatedly, yet should be useful in environments that are corrosive to elastomers, such as etch, chemical vapor deposition, or plasma chambers. This study focuses on measurements of quantitative gas influx, including mass-resolved measurements of permeation and outgassing, for various O-ring materials and conditioning sequences. The study compares the outgassing, leakage, and permeation of baked and unbaked elastomer seals in single ring configurations to baked and unbaked configurations of double O-rings with either an elastomer or an aluminum inner seal. (C) 1997 American Vacuum Society. C1 COLL WILLIAM & MARY,DEPT APPL SCI,WILLIAMSBURG,VA 23187. PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08540. NR 11 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 763 EP 767 DI 10.1116/1.580817 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100058 ER PT J AU Ren, F Vartuli, CB Pearton, SJ Abernathy, CR Donovan, SM MacKenzie, JD Shul, RJ Zolper, JC Lovejoy, ML Baca, AG HagerottCrawford, M Jones, KA AF Ren, F Vartuli, CB Pearton, SJ Abernathy, CR Donovan, SM MacKenzie, JD Shul, RJ Zolper, JC Lovejoy, ML Baca, AG HagerottCrawford, M Jones, KA TI Comparison of ohmic metallization schemes for InGaAlN SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID LIGHT-EMITTING-DIODES; FIELD-EFFECT TRANSISTOR; MOLECULAR-BEAM EPITAXY; GAN; CONTACTS; INN; RESISTANCE; GROWTH; BLUE AB W, WSi0.44, and Ti/Al contacts were examined on n(+)In(0.65)Ga(0.35)N, InN, and In0.75Al0.25N. W Was found to produce low specific contact resistance (Q(c) similar to 10(-7) Omega cm(2)) ohmic contacts to InGaN, while WSis showed an as-deposited Q(c) of 4 x 10(-7) Omega cm(2) but this degraded significantly with subsequent annealing, reaching 10(-5) Omega cm(2) at 700 degrees C. Ti/Al contacts on InGaN were stable to similar to 600 degrees C (Q(c) similar to 4 x 10(-7) Omega cm(2) at less than or equal to 600 degrees C). InN contacted with W and Ti/Al produced ohmic contacts with Q(c) similar to 10(-7) Omega cm(2) and for WSix Q(c) similar to 10(-6) Omega cm(2) and all three metallization schemes retained values less than or equal to 10(-6) Omega cm(2) up to 600 degrees C. The contact resistances for all of the metals were greater than or equal to 10(-4) Omega cm(2) on InAlN, and degraded with subsequent annealing. WSix contacts on InN grown graded from In0.6Al0.4N were also examined. The specific contact resistance was an order of magnitude lower (Q(c) similar to 10(-5) Omega cm(2)) after 500 degrees C anneal than that measured for WSix deposited directly on In0.6Al0.4N. Measurements of the temperature dependence of these contact structures showed that field emission was generally the most important conduction mechanism. (C) 1997 American Vacuum Society. C1 UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611. AT&T BELL LABS,LUCENT TECHNOL,MURRAY HILL,NJ 07974. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. USA,RES LAB,FT MONMOUTH,NJ 07703. NR 20 TC 9 Z9 9 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 802 EP 806 DI 10.1116/1.580711 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100065 ER PT J AU Malba, V Liberman, V Bernhardt, AF AF Malba, V Liberman, V Bernhardt, AF TI Vapor deposition polymerization of polyimide for microelectronic applications SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID FILMS AB We report the high-throughput vapor deposition polymerization (VDP) of smooth, uniform polyimide films for microelectronic applications. Using infrared (IR) spectroscopy, waveguiding refractive index measurements, atomic force microscopy, and matrix assisted laser desorption ionization, we have characterized both cured and uncured films. Uncured VDP films consist of oligomers (up to tetramers) and unreacted monomeric species. Cured VDP films are chemically identical to commercially available spin cast polyimides. Both IR and refractive index anisotropy are used to determine the extent of cure, and the stoichiometry of the cured film. Integration of the VDP films into a multichip module process is presented, and the application of VDP films in ultra-large-scale integrated circuit manufacturing is discussed. Finally, the vapor deposition of 3,3',4,4'-biphenyltetracarboxylic dianhydride and p-phenylenediamine, a high performance polyimide system, is presented. (C) 1997 American Vacuum Society. RP Malba, V (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 11 TC 14 Z9 15 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 844 EP 849 DI 10.1116/1.580718 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100072 ER PT J AU Deelman, PW Schowalter, LJ Thundat, T AF Deelman, PW Schowalter, LJ Thundat, T TI In situ measurements of temperature-dependent strain relaxation of Ge/Si(111) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID MOLECULAR-BEAM EPITAXY; STRESSED SOLIDS; INITIAL-STAGES; GROWTH; GE; LAYERS; SURFACES; MISFIT; INGAAS; SUPERLATTICES AB We have measured strain relaxation and clustering in Ge films grown by molecular beam epitaxy on Si(111) at substrate temperatures between 450 and 700 degrees C in real time with reflection high energy electron diffraction (RHEED). At 450 degrees C, we observe an oscillation of the surface lattice constant for the first 3.5 bilayers [(BLs) thicknesses were calibrated by Rutherford backscattering spectrometry], followed by a sharp two-dimensional-three-dimensional (2D-3D) growth mode transition, when transmission diffraction features appear in RHEED. The surface lattice constant then begins to relax at an initial rate of about 0.5%/BL. The mechanisms of island growth and strain relaxation change with growth temperature. At 500 degrees C, the surface lattice constant begins to relax after only 1 BL, and at 550 degrees C relaxation begins immediately. At both temperatures, however, 3D spots do not appear until after 3.5 BL. The initial rate of strain relaxation decreases with increasing temperature until, at 700 degrees C (when 3D spots never appear), it is only 0.04%/BL. This behavior may be explained by a temperature-dependent roughness length scale. At low temperature, atomic force microscope images show the development of small (similar to 1000 Angstrom), faceted islands with aspect ratios (height/width) on the order of 0.07. With increasing temperature, the formation of well-defined facets is inhibited. At 700 degrees C, islands grow very large from the outset, with aspect ratios less than 0.015. The islands are unable to thicken much, because dislocations can glide in easily at the edges, enabling the islands to grow laterally quickly. The strain in the ''new'' islands is not substantially less than that in the ''old'' islands. At the highest temperatures used, diffusion becomes a relevant mechanism for strain relief. (C) 1997 American Vacuum Society. C1 RENSSELAER POLYTECH INST,TROY,NY 12180. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 50 TC 14 Z9 14 U1 0 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 930 EP 935 DI 10.1116/1.580626 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100089 ER PT J AU Wu, X Coutts, TJ Mulligan, WP AF Wu, X Coutts, TJ Mulligan, WP TI Properties of transparent conducting oxides formed from CdO and ZnO alloyed with SnO2 and In2O3 SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID OPTICAL-PROPERTIES; THIN-FILMS AB In this article we examine the structural, electrical, and optical properties of several ternary alloy thin films. The alloys are zinc oxide and cadmium oxide, each of which was reacted with both indium oxide and tin oxide to form sputtering targets. The films were deposited by rf sputtering. X-ray diffraction spectroscopy showed that cadmium stannate, cadmium indate, and zinc stannate films were all polycrystalline spinel phase, but only when deposited at room temperature in pure oxygen and then annealed in argon/cadmium sulfide. The fourth alloy, zinc indate, exhibited a hexagonal phase when prepared under identical conditions. Cadmium stannate has one of the lowest resistivities of any transparent conducting oxide (TCO), has low absorbance in the visible spectrum, and is an excellent compromise between electrical and optical requirements. For this material, we show that a single phase is essential for the highest electrical conductivity and lowest optical absorbance. Zinc stannate has a resistivity more than one order of magnitude higher than cadmium stannate but, because of a larger band gap, has an even lower absorbance. We conclude that there is no ''best'' TCO, and the decision regarding which to use depends on the specific application and the weighting given to electrical versus optical properties. The zinc-bearing alloys are nontoxic, which may also be an attractive feature for many applications. C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. NR 11 TC 155 Z9 159 U1 4 U2 28 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1057 EP 1062 DI 10.1116/1.580429 PN 1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100112 ER PT J AU Jia, QX Foltyn, SR Hawley, M Wu, XD AF Jia, QX Foltyn, SR Hawley, M Wu, XD TI Pulsed laser deposition of conductive SrRuO3 thin films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID ELECTRICAL-PROPERTIES; ELECTRODES AB In this article we describe the pulsed laser deposition of smooth, particulate-free, and high conductivity SrRuO3, which are well suited for use as bottom electrodes in high capacity integrated thin-film capacitors. The films were heteroepitaxially grown on (100) LaAlO3 substrates at temperatures above 650 degrees C. Scanning tunneling microscopy measurements revealed that higher deposition temperatures produced larger grain sizes, and it was found from x-ray diffraction and four-probe tests that higher temperatures also led to improved film crystallinity and conductivity, respectively. At a deposition temperature of 775 degrees C, the room-temperature resistivity of SrRuO3 films was 280 mu Omega cm, and the residual resistivity ratio was 8.4, making these materials excellent candidates for use as thin-film electrodes. (C) 1997 American Vacuum Society. RP Jia, QX (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,G755,LOS ALAMOS,NM 87545, USA. RI Jia, Q. X./C-5194-2008 NR 11 TC 13 Z9 13 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1080 EP 1083 DI 10.1116/1.580433 PN 1 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100116 ER PT J AU Rej, DJ Davis, HA Olson, JC Remnev, GE Zakoutaev, AN Ryzhkov, VA Struts, VK Isakov, IF Shulov, VA Nochevnaya, NA Stinnett, RW Neau, EL Yatsui, K Jiang, W AF Rej, DJ Davis, HA Olson, JC Remnev, GE Zakoutaev, AN Ryzhkov, VA Struts, VK Isakov, IF Shulov, VA Nochevnaya, NA Stinnett, RW Neau, EL Yatsui, K Jiang, W TI Materials processing with intense pulsed ion beams SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID POWER; DEPOSITION AB We review research investigating the application of intense pulsed ion beams (IPIBs) for the surface treatment and coating of materials. The short range (0.1-10 mu m) and high-energy density (1-50 J/cm(2)) of these short-pulsed (less than or equal to 1 mu s) beams (with ion currents I=5-50 kA, and energies E=100-1000 keV) make them ideal in flash heating a target surface, similar to the more familiar pulsed laser processes. IPIB surface treatment induces rapid melt and solidification at up to 10(10) Wa causing amorphous layer formation and the producing nonequilibrium microstructures. At higher energy density the target surface is vaporized, and the ablated vapor is condensed as coatings onto adjacent substrates or as nanophase powders. Progress towards the development of robust, high-repetition rate IPIB accelerators is presented. (C) 1997 American Vacuum Society. C1 TOMSK NUCL PHYS ELECT & AUTOMAT RES INST,TOMSK 634050,RUSSIA. MOSCOW INST AVIAT TECHNOL,MOSCOW 125871,RUSSIA. QM TECHNOL INC,ALBUQUERQUE,NM 87109. NAGAOKA UNIV TECHNOL,BEAM TECHNOL LAB,NAGAOKA,NIIGATA 94021,JAPAN. RP Rej, DJ (reprint author), LOS ALAMOS NATL LAB,MS-D434,LOS ALAMOS,NM 87545, USA. OI Ryzhkov, Vladislav/0000-0002-5193-0318 NR 24 TC 75 Z9 81 U1 2 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1089 EP 1097 DI 10.1116/1.580435 PN 1 PG 9 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100118 ER PT J AU Martin, PM Stewart, DC Bennett, WD Affinito, JD Gross, ME AF Martin, PM Stewart, DC Bennett, WD Affinito, JD Gross, ME TI Multifunctional multilayer optical coatings SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc AB Multilayer optical coatings which heated and defogged the substrate, provided permeation barriers to water and air, and controlled emittance have been developed. All coatings were deposited by reactive de and rf magnetron sputtering, and the polymer multilayer process being developed at Pacific Northwest National Laboratory. The three coatings discussed in this article were applied to flexible and rigid substrates with diameters up to 28 cm. Fourteen-layers SiO2/Si3N4/TiO2/Ag coatings were applied to surveillance camera lenses to reject at least two laser wavelengths, defog the lens, and provide a high transmission notch at the operating wavelengths. The coatings were able to heat the substrates at a rate of 16 degrees C/min at relatively modest power inputs of 2 W/cm(2). The second coating had eight Cr/Si3N4 layers, and absorbed strongly at the 1.06 mu m laser wavelength and emitted strongly in the 3-5 mu m wavelength band. This coating was used in infrared displays. The last coating was a 15-layer polymer Al2O3 permeation barrier to water and air on a flexible polyethylene substrate. The coating was transparent. The permeation rates for oxygen were less than 2.55E-6 cm(3)/cm/day, and were less than 1.55E-6 g/cm(2)/day for water. The permeation test results provided further evidence for a synergistic relationship between polymer and oxide layers to prevent surface and solution diffusion of gases and water. (C) 1997 American Vacuum Society. RP Martin, PM (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 11 TC 4 Z9 4 U1 2 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1098 EP 1102 DI 10.1116/1.580436 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE731 UT WOS:A1997XE73100119 ER PT J AU Nelson, AJ Levi, D AF Nelson, AJ Levi, D TI Novel method for growing CdS on CdTe surfaces for passivation of surface states and heterojunction formation SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID GAAS-SURFACES; SULFIDE; SULFUR; INP AB Large-grain polycrystalline CdTe was subjected to in situ H2S plasma processing for <30 min at 100 and 200 degrees C. High-resolution x-ray photoemission measurements on the Cd 4d, Te 4d, and S 2p core levels, and the valence band were used to determine the resultant chemical environment of S and the electronic structure at the CdTe surface following plasma processing. Auger electron spectroscopy compositional depth profiling was also used to determine the distribution of S in the near surface region. Furthermore, time-resolved photoluminescence was used to measure carrier lifetimes and, thus, determine the degree of passivation of CdTe surface states. These results provide evidence for a CdS/CdS1-xTex/CdTe heterojunction device structure, as a result of the H2S plasma processing, and a reduction in the surface recombination velocity through passivation of surface states. This is a novel method of fabricating CdS/CdTe heterojunction devices. (C) 1997 American Vacuum Society. C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. RP Nelson, AJ (reprint author), COLORADO SCH MINES,DEPT PHYS,GOLDEN,CO 80401, USA. NR 11 TC 11 Z9 11 U1 2 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1119 EP 1123 DI 10.1116/1.580440 PN 2 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200001 ER PT J AU Liu, C Shu, D Kuzay, TM Wen, L Melendres, CA AF Liu, C Shu, D Kuzay, TM Wen, L Melendres, CA TI Ion beam induced surface modification of chemical vapor deposition diamond for x-ray beam position monitor applications SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID CARBON-FILMS; INDUCED CONDUCTIVITY; STRUCTURAL-CHANGES; LOW-ENERGY; TRANSFORMATION; IRRADIATION AB The Advanced Photon Source at Argonne National Laboratory is a third-generation synchrotron facility that generates powerful x-ray beams on its undulator beamlines for a variety of scientific and industrial user research programs. It is very important to know the position and the angle of the x-ray beam during experiments. Due to very high heat flux levels, several patented x-ray beam position monitors (XBPMs) exploiting beneficial characteristics of chemical vapor deposition (CVD) diamond have been developed. These XBPMs have a thin layer of low-atomic-mass metallic coating so that photoemission from the x rays generates a minute but measurable current for position determination. Another concept has been the graphitization of the CVD diamond surface to create a very thin, intrinsic conducting layer that can stand much higher temperatures and have minimal x-ray transmission losses compared to coated metallic layers. In the present study, a laboratory sputter ion source was used to transform selected surfaces of a CVD diamond substrate into graphite. The effect of 1-5 keV argon ion bombardment on CVD diamond surfaces at various target temperatures from 200 to 500 degrees C was studied using Auger electron spectroscopy and in situ electrical resistivity measurements. Graphitization after the ion bombardment was confirmed, and optimum conditions for graphitization were studied. Raman spectroscopy was applied to identify the overall diamond structure in the bulk of CVD diamond substrate after the ion bombardments. It was found that the target temperature plays an important role in the stability and electrical conductivity of the irradiated CVD diamonds. (C) 1997 American Vacuum Society. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439. RP Liu, C (reprint author), ARGONNE NATL LAB,ADV PHOTON SOURCE,ARGONNE,IL 60439, USA. NR 21 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 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1200 EP 1205 DI 10.1116/1.580593 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200016 ER PT J AU Rao, MG Dong, C AF Rao, MG Dong, C TI Evaluation of low cost residual gas analyzers for ultrahigh vacuum applications SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID QUADRUPOLE MASS SPECTROMETERS; PARTIAL-PRESSURE ANALYZERS; SENSITIVITY; PERFORMANCE AB In recent years several low cost computer controlled residual gas analyzers (RGAs) have been introduced into the market place. It would be very useful to know the performance characteristics of these RGAs in order to make an informed selection for UHV applications. The UHV applications include extreme sensitivity helium leak detection and monitoring of the residual gas spectra in UHV systems. In this article, the sensitivity and linearity data for nitrogen, hydrogen, and helium are presented in the pressure range 10(-8)-10(-1) Pa. Further, the relationships between focus voltage and ion currents, relative sensitivity, and fragmentation factor are also included. A direct comparison method is used in obtaining this data. Spinning rotor and extractor gauges are the transfer standard gauges used in Jefferson Lab's vacuum calibration facility, with which all the reported measurements here were carried out. (C) 1997 American Vacuum Society. RP Rao, MG (reprint author), THOMAS JEFFERSON NATL ACCELERATOR FACIL,NEWPORT NEWS,VA 23606, USA. NR 12 TC 11 Z9 11 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1312 EP 1318 DI 10.1116/1.580582 PN 2 PG 7 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200036 ER PT J AU Gardner, WL Baddorf, AP Holber, WM AF Gardner, WL Baddorf, AP Holber, WM TI Temperature and concentration effects on ozone ashing of photoresist SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID SILICON DIOXIDE FILMS; RADIATION-DAMAGE AB Photoresist removal was studied using single-crystal silicon samples mounted on a ceramic heater in an UHV compatible chamber. The photoresist-coated sample was exposed to an ozone-oxygen mixture at atmospheric pressure and at a flow rate of 4 sl/min. Resist removal rate was measured using in situ laser interferometry. The removal rate was found to be a linear function of ozone concentration with a slope of 0.82 nm/s/unit mass fraction at a substrate temperature of 200 degrees C. The linearity is consistent with a simple chemical rate model. Typical photoresist removal rates at a mass density fraction ozone concentration of 0.09 ranged from 2.5 to 13 nm/s for substrate temperatures ranging from 150 to 300 degrees C, respectively. These rates are comparable with those observed by others. Over this temperature range, removal rates follow standard Arrhenius behavior from which an activation energy of 5.2 kcal/mol was determined. This value is similar to the known activation energy of 6.0 kcal/mol for the thermal dissociation of ozone leading us to conclude that thermal dissociation is the rate limiting step in the process. Our result is also significantly lower than reported previously and may be more accurate since the substantial shrinkage of photoresist with temperature was accounted for in these results. Additionally, the combination of concentration and temperature information is shown to lead to an effective chemical reaction rate constant for the removal of photoresist with ozone. (C) 1997 American Vacuum Society. C1 APPL SCI & TECHNOL INC,WOBURN,MA 01801. RP Gardner, WL (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Baddorf, Arthur/I-1308-2016 OI Baddorf, Arthur/0000-0001-7023-2382 NR 9 TC 21 Z9 21 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1409 EP 1412 DI 10.1116/1.580551 PN 2 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200052 ER PT J AU Cook, SR Hoffbauer, MA AF Cook, SR Hoffbauer, MA TI Understanding gas-surface interactions from direct force measurements using a specialized torsion balance SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID ACCOMMODATION COEFFICIENTS; HIGH-VACUUM; GAUGE; MODEL AB Measurements of the magnitude and direction of the forces exerted on surfaces by molecular beams are used to obtain information about the microscopic properties of gas-surface interactions. The reduced force coefficients are introduced as a new set of parameters that completely describe the macroscopic average momentum transferred to a surface by incident molecules and can be used to obtain the flux-weighted average velocity and translational energy of the scattered molecules. This approach avoids the complications associated with obtaining macroscopic average quantities from averages of microscopic measurements and can be used to determine microscopic details concerning gas-surface interactions. Using a specialized torsion balance, the reduced force coefficients were determined from measurements of the forces exerted on surfaces of a solar panel array material, Kapton, SiO2-coated Kapton, and Z-93-coated Al by molecular beams of H-2, N-2, CO, and CO2, as a function of the angle of incidence. (C) 1997 American Vacuum Society. RP Cook, SR (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 24 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1553 EP 1557 DI 10.1116/1.580630 PN 2 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200080 ER PT J AU Rodriguez, JA Kuhn, M AF Rodriguez, JA Kuhn, M TI Interactions between sulfur and platinum in bimetallic surfaces: Reaction of S-2 with Pt-Al alloys SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID ELECTRONIC-PROPERTIES; PROMOTED SULFIDATION; CO-CHEMISORPTION; PHOTOEMISSION; AG/PT(111); ADSORPTION; CU/PT(111); ZN/PT(111); OXIDATION; ENERGIES AB The reaction of S-2 with Pt-Al alloys has been investigated using core- and valence-level photoemission. The Pt-Al alloys display a Pt 5d band that appears at much higher binding energy (1.8-2.1 eV) than in metallic Pt. This is accompanied by positive shifts in the Pt 4f (0.3-1.3 eV) and Al 2s (0.1-0.3 eV) core levels. The electronic perturbations in Pt do not increase the reactivity of this metal toward sulfur. After exposing Pt-Al alloys to S-2 gas, aluminum is extensively sulfided, while platinum remains in a metallic state. The Pt<->AlSx interactions are much weaker than Pt<->Al interactions. The chemisorption of S-2 induces the segregation of aluminum toward the surface of the alloys. The behavior observed for the PtAlx surfaces in the presence of sulfur is different from that seen for Cu/Pt (111) and Ag/Pt (111) surfaces, where the admetals promote Pt<->S interactions and the formation of several layers of platinum sulfide. Changes in the nature of the bimetallic bond and in the relative stability of the metal sulfides are responsible for this difference in behavior. (C) 1997 American Vacuum Society. RP Rodriguez, JA (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 32 TC 6 Z9 6 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1608 EP 1612 DI 10.1116/1.580640 PN 2 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200091 ER PT J AU Li, SY Rodriguez, JA Hrbek, J Huang, HH Xu, GQ AF Li, SY Rodriguez, JA Hrbek, J Huang, HH Xu, GQ TI Reaction of hydrogen with O/Ru(001) and RuOx films: Formation of hydroxyl and water SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID SUBSURFACE PENETRATION; RUTHENIUM 001; OXYGEN; RU(001); ADSORPTION; SURFACE; COADSORPTION; DESORPTION; OXIDATION; COVERAGES AB The interaction of gas phase atomic hydrogen with chemisorbed oxygen on Ru(001) and RuOx films has been investigated by means of Auger electron spectroscopy and thermal desorption spectroscopy at surface temperatures between 120 and 320 K. Although molecular hydrogen does not adsorb on oxygen saturated Ru(001) or RuOx films even at 120 K, atomic hydrogen reacts with oxygen on Ru(001) surfaces, and both D-2 and D2O desorb at temperatures below 500 g. The 2D(gas)+O-ad->D2Ogas reaction is approximately six times faster at 310 K than at 120 K. For RuOx films, a unity reaction probability was found at oxygen coverages above 3 monolayers (ML), while it decreased to 0.4 at theta(0) < 3 ML. Such variation can be attributed to a change in the structure of the oxide film. The reaction probably follows an Eley-Rideal mechanism where gas phase atomic hydrogen reacts with oxygen prior to thermal accommodation within the surface. The desorption of water is the rate limiting step at surface temperatures below 200 K, whereas the formation of water is the rate limiting step at higher temperatures. (C) 1997 American Vacuum Society. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP Li, SY (reprint author), NATL UNIV SINGAPORE,DEPT CHEM,SINGAPORE 119260,SINGAPORE. RI Xu, Guo Qin/C-2077-2013; Hrbek, Jan/I-1020-2013 NR 24 TC 10 Z9 10 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1692 EP 1697 DI 10.1116/1.580922 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200105 ER PT J AU Colera, I Gonzalez, R Soria, E deSegovia, JL Roman, EL Chen, Y AF Colera, I Gonzalez, R Soria, E deSegovia, JL Roman, EL Chen, Y TI Electron stimulated desorption study of the MgO(100)-D2O system SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID ENERGY-LOSS SPECTROSCOPY; PHOTOELECTRON DIFFRACTION; ION DESORPTION; MGO; SURFACES; MGO(001); OXIDES; AUGER AB A study of the MgO(100)-D2O system at 300 K by electron stimulated desorption (ESD) over the energy range up to 600 eV is presented. Auger electron spectroscopy is used as a complementary technique. ESD of the nearly perfect clean surface shows O+ desorbed ions as the main desorbed species with small amounts of H+ and F+ contaminants. The adsorption of D2O produces a dramatic decrease of the O+ intensity in the ESD spectrum and new signals corresponding to D+ and OD+ ions are observed. There is a first energy threshold at about 30 eV for D+ and H+ desorbed ions and a second one at 55 eV for O+ desorbed ions. The desorption of these ions corresponds to a primary excitation of the O 2s (24 eV) and Mg 2p (55 eV) core levels, respectively. The ion kinetic energy distribution of the desorbed O+ ion from the clean surface has two peaks at energies of 6 and 9 eV. The ion kinetic energy distribution of the D+ desorbed ions also shows a bimodal structure with most probable kinetic energies of 3 and 6.5 eV at 150 eV incident electron energy. The ion kinetic energy distribution of the H+ desorbed ions from the H contamination correlates quite well with that of the D+ desorbed ions both in shape and in energy. The most probable kinetic energy of the OD+ is about 3 eV. From these experiments, we propose an adsorption model with the D2O dissociated as OD+D. The D species bonds to O surface ions to form OsurfD radicals, and the OD species bonds to Mg surface ions. Since the experiments were performed at D2O constant pressure there is a large increase of the D+ intensity due to ESD of the D from OB species. The final equilibrium of the adsorbed species is a consequence of the D2O adsorption and ESD desorption rates. (C) 1997 American Vacuum Society. C1 CSIC, INST FIS APLICADA, LAB FIS VACIO & SUPERFICIES, CETEF L TORRES QUEVEDO, E-28006 MADRID, SPAIN. CSIC, INST CIENCIA MAT, E-28049 CANTO BLANCO, MADRID, SPAIN. US DOE, GERMANTOWN, MD 20874 USA. RP Colera, I (reprint author), UNIV CARLOS III MADRID, DEPT FIS, E-28911 LEGANES, MADRID, SPAIN. NR 23 TC 9 Z9 9 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1698 EP 1703 DI 10.1116/1.580923 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200106 ER PT J AU Gammon, WJ Mishra, SR Pappas, DP Goodman, KW Tobin, JG Schumann, FO Willis, R Denlinger, JD Rotenberg, E Warwick, A Smith, NV AF Gammon, WJ Mishra, SR Pappas, DP Goodman, KW Tobin, JG Schumann, FO Willis, R Denlinger, JD Rotenberg, E Warwick, A Smith, NV TI Comparison of magnetic linear dichroism in 4f photoemission and 4d-4f photoemission from Gd on Y(0001) SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID CORE-LEVEL PHOTOEMISSION; RESONANT PHOTOEMISSION; CIRCULAR-DICHROISM; SYSTEMS; GD(0001)/W(110) AB Magnetic linear dichroism (MLD) in 4d-4f resonant and 4f nonresonant photoemission (PE) is studied from thin epitaxial gadolinium films. In an angle resolved and high-energy resolution mode, experiments were conducted with the electric-field vector of the incident light perpendicular to the sample magnetization. Our results show a significant difference in behavior of MLD in resonant PE as compared to that in nonresonant PE. Off-resonance, the MLD signal is dominated by a negative feature at the low binding energy side of the peak. Near the 4d-4f resonance maximum, the MLD displays a plus-minus shape, with a negative signal at the low binding energy side of the 4f peak and a positive signal at the high binding energy side. Analysis of MLD in 4d-4f resonant PE may provide insight into interactions of the 4d core hole with the 4f core level in the intermediate state. (C) 1997 American Vacuum Society. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Gammon, WJ (reprint author), VIRGINIA COMMONWEALTH UNIV,DEPT PHYS,RICHMOND,VA 23284, USA. RI Rotenberg, Eli/B-3700-2009; Schumann, Frank /K-9364-2014; Tobin, James/O-6953-2015 OI Rotenberg, Eli/0000-0002-3979-8844; NR 18 TC 0 Z9 0 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1755 EP 1758 DI 10.1116/1.580864 PN 2 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200116 ER PT J AU Tobin, JG Goodman, KW Schumann, FO Willis, RF Kortright, JB Denlinger, JD Rotenberg, E Warwick, A Smith, NV AF Tobin, JG Goodman, KW Schumann, FO Willis, RF Kortright, JB Denlinger, JD Rotenberg, E Warwick, A Smith, NV TI Generalized description of magnetic x-ray circular dichroism in Fe 3p photoelectron emission SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID CORE-LEVEL PHOTOEMISSION; LINEARLY POLARIZED-LIGHT; 2P ABSORPTION-SPECTRA; BRANCHING RATIO; 4F PHOTOEMISSION; MULTILAYERS; FE/CU(001); NICKEL; SPECTROSCOPY; DIFFRACTION AB Extending a single electron picture previously developed by Venus, it will be shown that a generalized prediction of the magnetic x-ray circular dichroism in the angle-resolved photoelectron spectroscopy of the Fe 3p can be obtained. This determination can be performed without resorting to time-consuming and difficult spectral simulations. (C) 1997 American Vacuum Society. C1 PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Tobin, JG (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Rotenberg, Eli/B-3700-2009; Schumann, Frank /K-9364-2014; Tobin, James/O-6953-2015 OI Rotenberg, Eli/0000-0002-3979-8844; NR 41 TC 7 Z9 7 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1766 EP 1769 DI 10.1116/1.580866 PN 2 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200118 ER PT J AU Mattson, JE Osgood, RM Potter, CD Sowers, CH Bader, SD AF Mattson, JE Osgood, RM Potter, CD Sowers, CH Bader, SD TI Properties of Ni/Nb magnetic/superconducting multilayers SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 43rd American-Vacuum-Society Symposium CY OCT 14-18, 1996 CL PHILADELPHIA, PA SP Amer Vacuum Soc ID CRITICAL FIELDS; FE LAYERS; SUPERLATTICES; EXCHANGE; SUPERCONDUCTIVITY; MAGNETISM; OSCILLATION; TEMPERATURE AB We examine structural, magnetic, and superconducting properties of magnetic/superconducting Ni/Nb multilayers. The Ni(Nb) films are textured {111}({110}) and have smooth interfaces. The average moment of the Ni atoms in the structure drops by 80% from that of bulk Ni for 19 Angstrom thick Ni layers in proximity to 140 Angstrom thick Nb layers, and goes to zero for smaller Ni thicknesses. The Nb layer is not superconducting for thicknesses <100 Angstrom in the presence of a 19 Angstrom thick ferromagnetic Ni layer. The behavior of the superconducting critical temperature as a function of the superconducting layer thickness was fitted and an interfacial scattering parameter and scattering time for the paramagnetic Ni regime determined. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RI Bader, Samuel/A-2995-2013 NR 30 TC 20 Z9 20 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1997 VL 15 IS 3 BP 1774 EP 1779 DI 10.1116/1.580868 PN 2 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XE732 UT WOS:A1997XE73200120 ER PT J AU Shul, RJ Lovejoy, ML Word, JC Howard, AJ Rieger, DJ Kravitz, SH AF Shul, RJ Lovejoy, ML Word, JC Howard, AJ Rieger, DJ Kravitz, SH TI High rate reactive ion etch and electron cyclotron resonance etching of GaAs via holes using thick polyimide and photoresist masks SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID SURFACE-EMITTING LASERS; LOW-THRESHOLD; INP; PLASMA AB High rate etching of through-substrate via holes are essential to many GaAs electronic and photonic device applications. The backside via holes are relevant to monolithic microwave integrated circuits for low inductance grounding and increased circuit complexity. Via holes have also become important to photonic devices such as transmission modulators and vertical cavity surface emitting lasers (VCSELs) fabricated on absorbing substrates. We have investigated and compared reactive ion etch (RIE) and electron cyclotron resonance (ECR) etch results for GaAs via holes patterned with either photodefinable polyimide masks or conventional thick photoresist masks. We report GaAs etch rates for 5 min plasma exposures of similar to 8000 nm/min in a RIE-generated Cl-2/BCl3/SiCl4 plasma and similar to 3200 nm/min in a Cl-2/BCl3 ECR-generated plasma. (C) 1997 American Vacuum Society. RP Shul, RJ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 19 TC 21 Z9 22 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 1997 VL 15 IS 3 BP 657 EP 659 DI 10.1116/1.589365 PG 3 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA XF134 UT WOS:A1997XF13400021 ER PT J AU Fernandez, A Nguyen, HT Britten, JA Boyd, RD Perry, MD Kania, DR Hawryluk, AM AF Fernandez, A Nguyen, HT Britten, JA Boyd, RD Perry, MD Kania, DR Hawryluk, AM TI Use of interference lithography to pattern arrays of submicron resist structures for field emission flat panel displays SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID TRANSMISSION GRATINGS; CONES AB We report on the fabrication of square arrays of submicron resist dots and holes using interference lithography - a relatively simple and inexpensive way of generating periodic structures over large areas. The arrays are formed by exposing a layer of resist to a two-beam interference pattern followed by a second exposure after rotating the sample by 90 degrees. Arrays with periods of 0.67-3.2 mu m were fabricated. The size of the structures is accurately controlled by varying the exposure dose. The exposure latitude for patterning arrays of dots is +/-16% for a +/-10% change in structure-width when an optimum size-to-period ratio is chosen. Compared to dots, holes are patterned with a smaller process window. We show that arrays of dots with diameters as small as 0.20 mu m, sidewall slopes of 88 degrees, and aspect ratios as high as 3:1 can be produced. These structures are well suited for the production of field emission flat panel displays. (C) 1997 American Vacuum Society. RP Fernandez, A (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 20 TC 48 Z9 50 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 1997 VL 15 IS 3 BP 729 EP 735 DI 10.1116/1.589377 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA XF134 UT WOS:A1997XF13400034 ER PT J AU Fischer, TP Sturchio, NC Stix, J Arehart, GB Counce, D Williams, SN AF Fischer, TP Sturchio, NC Stix, J Arehart, GB Counce, D Williams, SN TI The chemical and isotopic composition of fumarolic gases and spring discharges from Galeras Volcano, Colombia SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE Galeras Volcano; eruptions; gases; volatiles; chemistry; fumaroles; springs; isotopes ID MOUNT ST-HELENS; DEL-RUIZ VOLCANO; HYDROTHERMAL SYSTEM; AUGUSTINE VOLCANO; CARBON-DIOXIDE; HE-3 EMISSION; WATER; EQUILIBRIA; CHEMISTRY; VOLATILES AB Galeras fumarole discharges have been collected since its reactivation, in 1988, through December 1995. The gases are dominated by H2O, CO2, S (as SO2 and H2S) and HCl. The relative proportions of these gases classify them as 'magmatic'. Thermodynamic equilibrium temperatures of the gases range from 260 to > 600 degrees C. The relative abundance of inert gases, N-2, Ar and He, can be used as 'tracers' to identify the source of the fumarole discharges. At Galeras the majority of the samples have a composition characteristic of gases originating from are-related magmas, with relatively high N-2 contents and minor He and Ar. During 1993, the year of frequent eruptions, the gas composition changed to basaltic or 'mantle-derived' gases, with significantly higher He contents. This is interpreted to be the result of injection of volatiles from a basaltic magma body at depth prior to and during the increased eruptive activity of 1993. The delta(13)C values for CO2 in fumarole discharges are typical of andesitic volcanoes and may indicate addition of MORE-derived CO2. The delta(15)N values for N-2 may indicate significant, contribution of N-2 from marine sediments and only minor contribution of MORE-derived N-2. The delta D and delta(18)O values of the discharging steam lie on a mixing trend between the isotopic composition of 'arc-related' magmatic water and O-18-shifted meteoric water. The most magmatic discharges have SD values of -30 to -35 parts per thousand; while the most meteoric discharges have values of -70 to -75 parts per thousand, similar to Galeras thermal spring waters. Galeras thermal water discharges consist of acid sulfate and bicarbonate waters. S/Cl ratios in the acid sulfate waters are similar to fumarole ratios, suggesting direct absorption of magmatic gases into shallow ground waters. This is supported by the essentially meteoric delta D and delta(18)O values of the discharges and by elevated He-3/He-4 ratios of thermal spring waters. The absorption of acid S- and Cl-rich gases yield acid waters which are capable of dissolving rocks. The thermal waters, however, are far from equilibrium with Galeras lavas and pyroclastic rocks, providing evidence of the immaturity of the Galeras hydrothermal. system. The SO4 and CI content, as well as the O and H isotopic composition of Galeras thermal springs vary with the activity of the volcano. C1 ARGONNE NATL LAB,ERD 203,ARGONNE,IL 60439. UNIV MONTREAL,DEPT GEOL,MONTREAL,PQ H3C 3J7,CANADA. LOS ALAMOS NATL LAB,EES 2,LOS ALAMOS,NM 87545. RP Fischer, TP (reprint author), ARIZONA STATE UNIV,DEPT GEOL,TEMPE,AZ 85287, USA. NR 75 TC 57 Z9 59 U1 3 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAY PY 1997 VL 77 IS 1-4 BP 229 EP 253 DI 10.1016/S0377-0273(96)00096-0 PG 25 WC Geosciences, Multidisciplinary SC Geology GA XC670 UT WOS:A1997XC67000015 ER PT J AU Vo, TV Blackburn, TR Casazza, LO Heasler, PG Mara, NL Phan, HK AF Vo, TV Blackburn, TR Casazza, LO Heasler, PG Mara, NL Phan, HK TI Reliability analysis in support of risk assessment for hydroelectric generating stations SO JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT-ASCE LA English DT Article AB In work sponsored by the U.S. Army Corps of Engineers (USAGE), Pacific Northwest Laboratory (PNL), Richland, Wash., has performed a frequency analysis regarding the nonroutine closure of water flow through the turbines of powerhouses along the Columbia and Snake Rivers. The analysis involved developing a frequency analysis model capable of producing frequency profiles of overspeed and flooding events as a function of time and the associated component importance rankings. Data regarding hydropower equipment failures from a previous study were used to estimate component failure rates within the model. The present paper summarizes the model development and quantification, and calculation of component importance measures. The results of this analysis can be used as input to further analyses to evaluate economic consequences of overspeed and flooding events and to provide policy recommendations for operations of hydroelectric generating stations. RP Vo, TV (reprint author), PACIFIC NW LAB, BATTELLE BLVD, RICHLAND, WA 99352 USA. NR 4 TC 1 Z9 1 U1 1 U2 4 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 SN 0733-9496 J9 J WATER RES PL-ASCE JI J. Water Resour. Plan. Manage.-ASCE PD MAY-JUN PY 1997 VL 123 IS 3 BP 179 EP 188 DI 10.1061/(ASCE)0733-9496(1997)123:3(179) PG 10 WC Engineering, Civil; Water Resources SC Engineering; Water Resources GA WV765 UT WOS:A1997WV76500006 ER PT J AU Goldsmith, J AF Goldsmith, J TI Turnkey Raman system senses atmospheric water vapor SO LASER FOCUS WORLD LA English DT Article RP Goldsmith, J (reprint author), SANDIA NATL LABS,POB 969,M-S 9057,LIVERMORE,CA 94551, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD MAY PY 1997 VL 33 IS 5 BP 241 EP 242 PG 2 WC Optics SC Optics GA WZ697 UT WOS:A1997WZ69700052 ER PT J AU Woloschak, GE AF Woloschak, GE TI Is PKC activation required for leukemia cell differentiation? SO LEUKEMIA RESEARCH LA English DT Article ID PROTEIN-KINASE-C; GROWTH-FACTOR-BETA; ESTER-INDUCED DIFFERENTIATION; PHORBOL ESTER; RECEPTOR EXPRESSION; INHIBITORY FACTOR; U937 CELLS; MODULATION; RESISTANCE; PATHWAYS RP Woloschak, GE (reprint author), ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 NR 42 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0145-2126 J9 LEUKEMIA RES JI Leuk. Res. PD MAY PY 1997 VL 21 IS 5 BP 411 EP 414 DI 10.1016/S0145-2126(96)00121-X PG 4 WC Oncology; Hematology SC Oncology; Hematology GA XH854 UT WOS:A1997XH85400008 PM 9225068 ER PT J AU Akan, E ChangLiu, CM Watanabe, J Ishizawa, K Woloschak, GE AF Akan, E ChangLiu, CM Watanabe, J Ishizawa, K Woloschak, GE TI The effects of vinblastine on the expression of human immunodeficiency virus type 1 long terminal repeat SO LEUKEMIA RESEARCH LA English DT Article DE DNA-damaging agents; gene expression; HIV expression; vinblastine; salicylic acid ID PROTEIN-KINASE-C; NF-KAPPA-B; GENE-EXPRESSION; ULTRAVIOLET-RADIATION; IONIZING-RADIATION; ACTIVATION; INHIBITION; ASPIRIN; CELLS AB Previous work by our group has demonstrated induction of the HIV-LTR following exposure of cells to various DNA-damaging agents such as ultraviolet (UV) light, cisplatin, and doxorubicin. The current experiments were designed to determine the relative effects of the anti-mitotic drug vinblastine on expression of the HIV-LTR. Using human cervical carcinoma (HeLa) cells stably transfected with the chloramphenicol acetyl transferase (CAT) reporter transcriptionally driven by the HIV-LTR promoter, we demonstrated a 9-10-fold induction at 48-72 h following vinblastine treatment. Previous experiments had demonstrated repression of cisplatin or doxorubicin-mediated HIV induction by treatment with salicylic acid. The vinblastine induction also was repressed by salicylic acid treatment, but not by treatment with indomethacin, suggesting a role for the NFkB pathway in the inductive response. When UV exposure was coupled to the vinblastine treatment, there was no additive or synergistic effect evident, suggesting similar paths of induction between the two agents. Northern blots demonstrated that these agents were operating at the level of transcription and that salicylic acid inhibited vinblastine-mediated induction of HIV-LTR-CAT mRNA only if administered at the same time as vinblastine; addition of salicylic acid 2 h later had no effect on transcript accumulation. All combinations of treatments with vinblastine and/or salicylic acid markedly reduced cell survival. (C) 1997 Elsevier Science Ltd. C1 ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,ARGONNE,IL 60439. UNIV ILLINOIS,MED CTR,CHICAGO,IL. TOHOKU UNIV,SCH MED,DEPT RADIAT RES,SENDAI,MIYAGI 98077,JAPAN. RI Woloschak, Gayle/A-3799-2017 OI Woloschak, Gayle/0000-0001-9209-8954 NR 16 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0145-2126 J9 LEUKEMIA RES JI Leuk. Res. PD MAY PY 1997 VL 21 IS 5 BP 459 EP 464 DI 10.1016/S0145-2126(96)00125-7 PG 6 WC Oncology; Hematology SC Oncology; Hematology GA XH854 UT WOS:A1997XH85400015 PM 9225075 ER PT J AU Burton, HD AF Burton, HD TI Darwin among the machines: The evolution of global intelligence - Dyson,GB SO LIBRARY JOURNAL LA English DT Book Review RP Burton, HD (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 SN 0363-0277 J9 LIBR J JI Libr. J. PD MAY 1 PY 1997 VL 122 IS 8 BP 130 EP & PG 2 WC Information Science & Library Science SC Information Science & Library Science GA WV949 UT WOS:A1997WV94900183 ER PT J AU Mulholland, PJ Marzolf, ER Webster, JR Hart, DR Hendricks, SP AF Mulholland, PJ Marzolf, ER Webster, JR Hart, DR Hendricks, SP TI Evidence that hyporheic zones increase heterotrophic metabolism and phosphorus uptake in forest streams SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID DISSOLVED ORGANIC-CARBON; TRANSIENT STORAGE MODEL; SURFACE-WATER; ECOSYSTEM METABOLISM; SOLUTE TRANSPORT; RIVER CONTINUUM; DESERT STREAM; EXCHANGE; SEDIMENTS; DYNAMICS AB We used nondisruptive, whole-stream methods to measure hydraulic characteristics, ecosystem metabolism, and phosphorus cycling in the west fork of Walker Branch (WE), Tennessee and in Hugh White Creek (HWC), North Carolina. Although similar in many of their hydrological and chemical characteristics, transient storage zone volume in HWC was relatively large (similar to 1.5 times that of the flowing water zone), whereas transient storage zone volume in WE was small (similar to 0.1 times that of the flowing water zone). Both streams were highly heterotrophic (gross primary production:total respiration ratios <0.1), although respiration rate was similar to 2.4 times greater in HWC than in WE. Phosphorus uptake rate was similar to 2.6 times, greater in HWC than in WE, and P uptake length was 5 times longer in WE than in HWC. Analysis of P-33:H-3 ratio profiles from (PO4)-P-33 and (H2O)-H-3 injection experiments indicated that P uptake within the transient storage zone accounted for similar to 43% of the total P uptake in HWC but was negligible in WE, explaining, in part, the difference in total P uptake rate between these streams. The higher rate of P uptake in the surface zone, shorter P uptake length, and larger ratio of P uptake:respiration in HWC compared with WE suggest that the microbial community in HWC exerts a greater demand for and has a greater affinity for streamwater P presumably as a result of a greater supply of labile organic matter and/or lower nutrient levels in HWC. C1 VIRGINIA TECH,DEPT BIOL,BLACKSBURG,VA 24061. TEL AVIV UNIV,DEPT ZOOL,IL-69978 RAMAT AVIV,TEL AVIV,ISRAEL. HANCOCK BIOL STN,MURRAY,KY 42071. RP Mulholland, PJ (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Mulholland, Patrick/C-3142-2012 NR 29 TC 221 Z9 227 U1 6 U2 53 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 1997 VL 42 IS 3 BP 443 EP 451 PG 9 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA XZ091 UT WOS:A1997XZ09100004 ER PT J AU Richardson, TJ Wen, SJ Striebel, KA Ross, PN Cairns, EJ AF Richardson, TJ Wen, SJ Striebel, KA Ross, PN Cairns, EJ TI FTIR spectroscopy of metal oxide insertion materials: Analysis of LixMn2O4 spinel electrodes SO MATERIALS RESEARCH BULLETIN LA English DT Article DE oxides; infrared spectroscopy; energy storage; phase transitions ID LI+ EXTRACTION/INSERTION REACTIONS; MANGANESE-DIOXIDE; LITHIUM INSERTION; AQUEOUS-PHASE; LIMN2O4; ELECTROCHEMISTRY; SPECTRA; SITES AB Fourier transform infrared (FTIR) spectra were obtained from spinel-type lithium manganese oxides of composition LixMn2O4 With 0 < x < 2.4, prepared by both chemical and electrochemical means. Each phase in this system has a distinct spectrum which is characteristic of the local (short-range) structure. Mixtures of phases were analyzed using the method of scaled absorbance subtraction. The results correlate well with previously reported XRD and neutron diffraction analyses as well as with phase behavior indicated by electrochemical measurements. FTIR spectroscopy thus provides both qualitative and quantitative information and is shown to be an effective companion technique to X-ray diffraction. Copyright (C) 1997 Elsevier Science Ltd. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV MAT SCI, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV ENERGY & ENVIRONM, BERKELEY, CA 94720 USA. RI Cairns, Elton/E-8873-2012 OI Cairns, Elton/0000-0002-1179-7591 NR 30 TC 37 Z9 38 U1 2 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-5408 EI 1873-4227 J9 MATER RES BULL JI Mater. Res. Bull. PD MAY PY 1997 VL 32 IS 5 BP 609 EP 618 DI 10.1016/S0025-5408(97)00022-6 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA WY264 UT WOS:A1997WY26400017 ER PT J AU Liu, CL Leboeuf, JN Wood, RF Geobegan, DB Donato, JM Chen, KR Puretzky, AA AF Liu, CL Leboeuf, JN Wood, RF Geobegan, DB Donato, JM Chen, KR Puretzky, AA TI Computational modeling of physical processes during laser ablation SO MATERIALS SCIENCE AND ENGINEERING B-SOLID STATE MATERIALS FOR ADVANCED TECHNOLOGY LA English DT Article; Proceedings Paper CT Proceedings of the Engineering-Foundation Conference on Materials Processing and Advanced Applications of Lasers CY MAY 01-06, 1994 CL PALM COAST, FL SP Engn Fdn DE computational modeling; laser ablation; laser annealing; vapor breakdown; particle hydrodynamic; gas dynamic ID PARTICLE CODE AB A combined theoretical and experimental effort to model various physical processes Juring laser ablation of solids using a variety of computational techniques is described. Currently the focus of the modeling is on the following areas: (a) rapid transformations through the liquid and vapor phases under possibly nonequilibrium thermodynamic conditions induced by laser-solid interactions; (b) breakdown of the vapor into a plasma in the early stages of ablation through both electronic and photoionization processes; (c) hydrodynamic behavior of the vapor/plasma during and after ablation; and (d) the effects of initial conditions in the vapor, in particular, the nature of the initial velocity distribution, on the characteristics of subsequent vapor expansion. The results from the modeling will be compared with experimental observations where possible. (C) 1997 Elsevier Science S.A. C1 OAK RIDGE NATL LAB,DIV FUS ENERGY,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV ENGN PHYS & MATH,OAK RIDGE,TN 37831. RI Puretzky, Alexander/B-5567-2016 OI Puretzky, Alexander/0000-0002-9996-4429 NR 14 TC 27 Z9 27 U1 1 U2 4 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5107 J9 MAT SCI ENG B-SOLID JI Mater. Sci. Eng. B-Solid State Mater. Adv. Technol. PD MAY PY 1997 VL 47 IS 1 BP 70 EP 77 DI 10.1016/S0921-5107(96)01883-1 PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA XH393 UT WOS:A1997XH39300011 ER PT J AU Bardenhagen, SG Stout, MG Gray, GT AF Bardenhagen, SG Stout, MG Gray, GT TI Three-dimensional, finite deformation, viscoplastic constitutive models for polymeric materials SO MECHANICS OF MATERIALS LA English DT Article DE polymers; constitutive modeling; viscoelasticity; viscoplasticity; strain-rate sensitivity ID GLASSY-POLYMERS; VISCOELASTIC RESPONSE; PLASTIC-DEFORMATION; BEHAVIOR AB A general methodology for developing three-dimensional. finite deformation, viscoplastic constitutive models for polymeric materials is presented. The development begins with the presentation of a one-dimensional spring and dashpot construction which exhibits behavior typical of polymeric materials, namely strain-rate dependence, stress relaxation, and creep. The one-dimensional construction serves as a starting point for the development of a three-dimensional, finite deformation, viscoplastic constitutive model which also exhibits typical polymeric behavior. Furthermore, the three-dimensional constitutive model may be easily generalized to incorporate an arbitrary number of inelastic processes, representing (inelastic) microstructural deformation mechanisms operating on different time scales. Strain-rate dependence, stress relaxation, and creep phenomena are discussed in detail for a simple version of the constitutive model. Test data for a particular polymer is used to validate the simple model. It is concluded that the methodology provides a flexible approach to modeling polymeric materials over a wide range of loading conditions. C1 LOS ALAMOS NATL LAB,DIV THEORET,GRP T3,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,GRP MST5,LOS ALAMOS,NM 87545. NR 28 TC 96 Z9 98 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6636 J9 MECH MATER JI Mech. Mater. PD MAY-JUN PY 1997 VL 25 IS 4 BP 235 EP 253 DI 10.1016/S0167-6636(97)00007-0 PG 19 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA XG175 UT WOS:A1997XG17500001 ER PT J AU Becker, TL McNaney, JM Cannon, RM Ritchie, RO AF Becker, TL McNaney, JM Cannon, RM Ritchie, RO TI Limitations on the use of the mixed-mode delaminating beam test specimen: Effects of the size of the region of K-dominance SO MECHANICS OF MATERIALS LA English DT Article DE interface fracture; K-dominance; small scale yielding; MMDB specimen ID INTERFACIAL FRACTURE-TOUGHNESS; METAL CERAMIC INTERFACE; BIMATERIAL INTERFACES; CRACK; RESISTANCE; STRESS; PLASTICITY AB The mixed-mode delaminating beam (MMDB) is a widely used test geometry designed to measure the fracture resistance of bimaterial interfaces under mixed-mode loading conditions. In the present work, linear-elastic finite element analyses are employed to determine the complex stress intensity factor, K, for an interfacial crack in this sample; results are found to confirm those of previous studies of the bilayer specimen. However, the numerical results further reveal that the region of K-dominance near the crack tip is very limited, extending merely similar to 1/100 to 1/1000 of the sample height, about an order of magnitude smaller than for other common fracture-mechanics test samples. Analyses performed for this specimen geometry modified to include a thin sandwiched interlayer also indicate a very limited region of K-dominance, for example, extending similar to 1/10 of the height of the sandwiched layer from the crack tip for very thin sandwiched layers. For the sandwiched geometry, two situations leading to a useful small scale yielding condition are described. Examples of the use of this specimen in the evaluation of the fracture toughness of ceramic joints are cited from the literature and comparisons are made between the size of the K-dominant region and the extent of crack tip plasticity. Based on these comparisons, the geometry-independent predictive power of linear-elastic fracture mechanics for common bimaterial couples and specimen dimensions using this geometry is challenged. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MECH ENGN,BERKELEY,CA 94720. RI Ritchie, Robert/A-8066-2008; McNaney, James/F-5258-2013 OI Ritchie, Robert/0000-0002-0501-6998; NR 33 TC 41 Z9 41 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6636 J9 MECH MATER JI Mech. Mater. PD MAY-JUN PY 1997 VL 25 IS 4 BP 291 EP 308 DI 10.1016/S0167-6636(97)00010-0 PG 18 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA XG175 UT WOS:A1997XG17500005 ER PT J AU Syn, CK Lesuer, DR Sherby, OD AF Syn, CK Lesuer, DR Sherby, OD TI Tensile properties of a thermomechanically processed ductile iron SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID ULTRAHIGH-CARBON-STEELS AB A ductile cast iron was continuously hot-and-warm-rolled or one-step-forged from a temperature in the austenite range (900 degrees C to 1100 degrees C) to a temperature below the A(1) temperature. Various amounts of reduction were used (from 60 to more than 90 pct). Tensile properties including tensile strength and total elongation were measured along the directions parallel and transverse to the rolling direction and along the direction transverse to the forging direction. The tensile ductility and strength both increase with a decrease in the amount of hot-and-warm working (HWW). Compared with the results obtained by other investigators, the present results showed higher strengths and ductilities over the same range of reduction in thickness. The improvement in properties is related to the lower temperature of the postprocessing heat treatment given in this study (600 degrees C) compared to other studies (900 degrees C). The low temperature of heat treatment leads to a structure of fine graphite in a matrix of ferrite and carbides, whereas the high temperature of heat treatment leads to coarse graphite in a matrix of carbide-free ferrite. The delay in failure from the presence of the small graphite constituent results in an increase in tensile ductility with an accompanying increase in tensile strength. C1 STANFORD UNIV,DEPT MAT SCI & ENGN,STANFORD,CA 94305. RP Syn, CK (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 TC 7 Z9 7 U1 0 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD MAY PY 1997 VL 28 IS 5 BP 1213 EP 1218 DI 10.1007/s11661-997-0286-0 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA WY668 UT WOS:A1997WY66800011 ER PT J AU Colwell, FS Lehman, RM AF Colwell, FS Lehman, RM TI Carbon source utilization profiles for microbial communities from hydrologically distinct zones in a basalt aquifer SO MICROBIAL ECOLOGY LA English DT Article ID DEEP SUBSURFACE SEDIMENTS; TERRESTRIAL SUBSURFACE; PHYSIOLOGICAL DIVERSITY; HETEROTROPHIC BACTERIA; COASTAL-PLAIN; SURFACE SOIL; MICROORGANISMS; SITE; GROUNDWATER; PRISTINE AB The Eastern Snake River Plain aquifer has hydrologically distinct zones in basalt flow units and interbedded sediments. The zones that differ markedly in physical features (e.g., porosity and permeability) have similar groundwater chemistries. The primary objective of this study was to determine whether intervals within the aquifer that contrast on the basis of permeability have distinct communities of unattached microorganisms based on functional attributes. Aquifer sampling was conducted using a submersible pump to obtain whole-well (w) samples, and a straddle-packer pump (SPP) to obtain samples from specific aquifer intervals that were vertically distributed in the open borehole. The SPP intervals ranged from 4.6 to 6.1 m in length and were located from 142 to 198 m below land surface. A community-level physiological profile (CLPP) was used to determine functional characteristics of the microbial community in the groundwater samples based on the community response to 95 sole organic carbon sources. Surface soil samples at the site were analyzed in a similar manner for comparison. The total bacterial population in the groundwater samples was determined using acridine orange direct counts. Principal components analysis (PCA) of the CLPP dataset distinguished between surface soil and aquifer microbial communities. Soils scored low in the respiration of polymers, esters, and amines and high in bromosuccinate, when compared to aquifer samples. The W samples were distinct from SPP samples. The 180- to 198-m interval, with the lowest hydraulic conductivity of all intervals, yielded samples that grouped together by PCA and cluster analysis. Direct counts varied between 10(4) and 10(5) cells ml(-1), and showed no relationship to the depth of the sample or to the hydraulic conductivity of the sample interval. Differences between microbial communities based on respired carbon compounds were discerned in separate, hydrologically distinct intervals within the borehole, although these differences were slight. Differences among aquifer intervals were less apparent than differences between surface soils and groundwater, and may be related to variations in hydrologic properties over the intervals sampled. The results suggest that free-living microbial communities in basalt aquifers, as characterized by CLPP are relatively unaffected by wide ranges in hydraulic conductivity when other abiotic factors are essentially equal. RP Colwell, FS (reprint author), IDAHO NATL ENGN LAB,DEPT BIOTECHNOL,POB 1625,IDAHO FALLS,ID 83415, USA. OI Lehman, Michael/0000-0002-3391-3178 NR 47 TC 14 Z9 14 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD MAY-JUN PY 1997 VL 33 IS 3 BP 240 EP 251 DI 10.1007/s002489900027 PG 12 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA WT212 UT WOS:A1997WT21200009 ER PT J AU Brennen, RA Hecht, MH Wiberg, DV Manion, SJ Bonivert, WD Hruby, JM Scholz, ML Stowe, TD Kenny, TW Jackson, KH Malek, CK AF Brennen, RA Hecht, MH Wiberg, DV Manion, SJ Bonivert, WD Hruby, JM Scholz, ML Stowe, TD Kenny, TW Jackson, KH Malek, CK TI Fabrication of collimating grids for an x-ray solar telescope using LIGA methods SO MICROSYSTEM TECHNOLOGIES LA English DT Article AB We are fabricating sub-collimating X-ray grids that are to be used in an orbiting solar X-ray telescope. The telescope optics consist of twelve rotating pairs of high aspect ratio grids. The pitch for the grids ranges from 34 mu m to 317 mu m. The grid thickness-to-grid-slit ratio must be approximately 50:1, resulting in grid thicknesses of 1 to 10 millimeters. We are implementing a design in which a 34 mu m pitch, free-standing PMMA grid is fabricated with 20 mu m wide slits through a 800 mu m thickness. After exposure and developing, metal is electrodeposited into the slits in the PMMA grid and the PMMA is left in place to hold the individual metal pieces. For optimum imaging performance, the root-mean-square pitch of the two grids of each pair must match to within 1 part in 10000 and simultaneous exposures of stacked sheets of PMMA have insured that this requirement is met. C1 JET PROP LAB,PASADENA,CA 91109. SANDIA NATL LABS,LIVERMORE,CA 94551. STANFORD UNIV,STANFORD,CA 94305. LAWRENCE BERKELEY LAB,BERKELEY,CA. LOUISIANA STATE UNIV,CTR ADV MICROSTRUCT & DEVICES,BATON ROUGE,LA 70803. RP Brennen, RA (reprint author), HEWLETT PACKARD CORP,3500 DEER CREEK RD,PALO ALTO,CA 94303, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0946-7076 J9 MICROSYST TECHNOL JI Microsyst. Technol. PD MAY PY 1997 VL 3 IS 3 BP 91 EP 96 DI 10.1007/s005420050062 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA YD297 UT WOS:A1997YD29700001 ER PT J AU Sandhu, C Garbe, J Bhattacharya, N Daksis, J Pan, CH Yaswen, P Koh, J Slingerland, JM Stampfer, MR AF Sandhu, C Garbe, J Bhattacharya, N Daksis, J Pan, CH Yaswen, P Koh, J Slingerland, JM Stampfer, MR TI Transforming growth factor beta stabilizes p15(INK4B) protein, increases p15(INK4B)-cdk4 complexes, and inhibits cyclin D1 cdk4 association in human mammary epithelial cells SO MOLECULAR AND CELLULAR BIOLOGY LA English DT Article ID DEPENDENT KINASE INHIBITOR; TUMOR-SUPPRESSOR GENE; TGF-BETA; RETINOBLASTOMA-PROTEIN; DNA-REPLICATION; POTENTIAL MEDIATOR; MAMMALIAN-CELLS; CANCER-CELLS; P21; EXPRESSION AB The effects of transforming growth factor beta (TGF-beta) were studied in closely related human mammary epithelial cells (HMEC), both finite-life-span 184 cells and immortal derivatives, 184A1(S), and 184A1L5(R), which differ in their cell cycle responses to TGF-beta but express type I and type II TGF-beta receptors and retain TGF-beta induction of extracellular matrix. The arrest-resistant phenotype was not due to loss of cyclin-dependent kinase (cdk) inhibitors. TGF-beta was shown to regulate p15(INK4B) expression at at least two levels: mRNA accumulation and protein stability. In TGF-beta-arrested HMEC, there was not only an increase in p15 mRNA but also a major increase in p15(INK4B) protein stability. As cdk4- and cdk6-associated p15(INK4B) increased during TGF-beta arrest of sensitive cells, there was a loss of cyclin D1, p21(Cip1), and p27(Kip1) from these kinase complexes, and cyclin E-cdk2-associated p27(Kip1) increased. In HMEC, p15(INK4B) complexes did not contain detectable cyclin. p15(INK4B) from both sensitive and resistant cells could displace in vitro cyclin D1, p21(Cip1), and p27(Kip1) from cdk4 isolated from sensitive cells. Cyclin D1 could not be displaced from cdk4 in the resistant 184A1L5(R) cell lysates. Thus, in TGF-beta arrest, p15(INK4B) may displace already associated cyclin D1 from cdks and prevent new cyclin D1-cdk complexes from forming. Furthermore, p27(Kip1) binding shifts from cdk4 to cyclin E-cdk2 during TGF-beta-mediated arrest. The importance of posttranslational regulation of p15(INK4B) by TGF-beta is underlined by the observation that in TGF-beta-resistant 184A1L5(R), although the p15 transcript increased, p15(INK4B) protein was not stabilized and did not accumulate, and cyclin D1-cdk association and kinase activation were not inhibited. C1 TORONTO SUNNYBROOK REG CANC CTR, DIV CANC BIOL RES, TORONTO, ON M4N 3M5, CANADA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. MASSACHUSETTS GEN HOSP, CTR CANC, CHARLESTOWN, MA 02129 USA. FU NCI NIH HHS [CA-24844] NR 77 TC 148 Z9 154 U1 0 U2 3 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0270-7306 J9 MOL CELL BIOL JI Mol. Cell. Biol. PD MAY PY 1997 VL 17 IS 5 BP 2458 EP 2467 PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA WV199 UT WOS:A1997WV19900011 PM 9111314 ER PT J AU Chandler, DP Fredrickson, JK Brockman, FJ AF Chandler, DP Fredrickson, JK Brockman, FJ TI Effect of PCR template concentration on the composition and distribution of total community 16S rDNA clone libraries SO MOLECULAR ECOLOGY LA English DT Article DE 16S; rRNA; PCR; sediment; bias; bacteria ID POLYMERASE CHAIN-REACTION; RIBOSOMAL-RNA GENES; YELLOWSTONE-NATIONAL-PARK; HYDROTHERMAL VENT SYSTEM; SUBSURFACE SEDIMENTS; REACTION AMPLIFICATION; MICROBIAL COMMUNITY; BACTERIAL DIVERSITY; LOIHI SEAMOUNT; DNA EXTRACTION AB Total DNA from sediment samples was isolated by a direct lysis technique. Purified DNA was used as template either undiluted or diluted 1 : 10 prior to polymerase chain reaction (PCR) amplification of 16S rRNA genes. Full-length inserts were analysed for restriction fragment length polymorphisms (RFLP) with the enzyme Cfo1, and the resulting distribution and abundance of RFLP patterns compared between the undiluted and diluted PCR reactions. Results indicate that for low PCR template concentrations, in the range from a few picograms to tens of picograms DNA, proportional representation of specific RFLP types was not reproducible upon template dilution, confirming that PCR amplification of 16S rDNA cannot be used directly to infer microbial abundance. In particular, only 15-24% of the RFLP types recovered from a sample were present in both the undiluted and diluted extracts. We propose that very low template concentrations in the PCR generate random fluctuations in priming efficiency, which led to the contrast in the RFLP types observed in the libraries from the undiluted and diluted extracts. RP Chandler, DP (reprint author), PACIFIC NW NATL LAB,ENVIRONM MICROBIOL GRP,900 BATTELLE BLVD,MAIL STOP K4 06,RICHLAND,WA 99352, USA. NR 41 TC 159 Z9 170 U1 1 U2 15 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD MAY PY 1997 VL 6 IS 5 BP 475 EP 482 DI 10.1046/j.1365-294X.1997.00205.x PG 8 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA WY864 UT WOS:A1997WY86400008 PM 9161015 ER PT J AU Danon, MJ Giometti, CS Manaligod, JR Swisher, C AF Danon, MJ Giometti, CS Manaligod, JR Swisher, C TI Sequential muscle biopsy changes in a case of congenital myopathy SO MUSCLE & NERVE LA English DT Article DE congenital myopathy; congenital fiber disproportion; maturational arrest; two-dimensional electrophoresis ID FIBER-TYPE DISPROPORTION; CENTRONUCLEAR MYOTUBULAR MYOPATHY; CENTRAL NUCLEI; HYPOTROPHY; PATTERNS; VIMENTIN; DESMIN; FETAL; XQ28 AB Muscle biopsies at age 7 months in a set of dizygotic male twins born floppy showed typical features of congenital fiber-type disproportion (CFTD). One of the twins died at age 1 year due to respiratory complications. The second one subsequently developed facial diplegia and external ophthalmoplegia. He never walked, remained wheelchair bound, and required continuous ventilatory support. He underwent repeat biopsies at ages 2 and 4, which showed many atrophic type 1 muscle fibers containing central nuclei and severe type 2 fiber deficiency compatible with centronuclear myopathy (CNM). Two-dimensional gel electrophoresis of muscle showed decreases of type II myosin light chains 2 and 3, suggestive of histochemical type I fiber deficiency. The progressive nature of morphological changes in one of our patients cannot be explained by maturational arrest. Repeat biopsies in cases of CFTD with rapid clinical deterioration may very well show CNM. (C) 1997 John Wiley & Sons, Inc. C1 NEW YORK MED COLL,DEPT PATHOL,VALHALLA,NY 10595. ARGONNE NATL LAB,DIV BIOL ENVIRONM & MED RES,ARGONNE,IL 60439. UNIV ILLINOIS,COLL MED,DEPT PATHOL,CHICAGO,IL 60612. CHILDRENS MEM HOSP,DIV PEDIAT NEUROL,CHICAGO,IL 60614. RP Danon, MJ (reprint author), NEW YORK MED COLL,DEPT NEUROL,MUNGER PAVIL,VALHALLA,NY 10595, USA. NR 26 TC 16 Z9 18 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0148-639X J9 MUSCLE NERVE JI Muscle Nerve PD MAY PY 1997 VL 20 IS 5 BP 561 EP 569 DI 10.1002/(SICI)1097-4598(199705)20:5<561::AID-MUS4>3.0.CO;2-7 PG 9 WC Clinical Neurology; Neurosciences SC Neurosciences & Neurology GA WW605 UT WOS:A1997WW60500004 PM 9140362 ER PT J AU Sanders, PG Fougere, GE Thompson, LJ Eastman, JA Weertman, JR AF Sanders, PG Fougere, GE Thompson, LJ Eastman, JA Weertman, JR TI Improvements in the synthesis and compaction of nanocrystalline materials SO NANOSTRUCTURED MATERIALS LA English DT Article ID ENHANCED SPECIFIC-HEAT AB Processing defects such as porosity and impurities may be present in nanocrystalline materials produced by inert gas condensation and compaction. New synthesis and compaction devices were designed and built to improve the sample quality. Nanocrystalline Pd and Cu made in these new systems have reduced levels of hydrogen and oxygen impurities and increased density compared with materials made under similar conditions in the old system. It was more difficult to produce and maintain extremely fine grain sizes in the high-purity, high-density nanocrystalline Pd and Cu synthesized in this study. (C) 1997 Acta Metallurgica Inc. C1 ARGONNE NATL LAB,DIV SCI MAT,ARGONNE,IL 60439. NORTHWESTERN UNIV,DEPT MAT SCI & ENGN,EVANSTON,IL 60208. RI Weertman, Julia/B-7540-2009; Eastman, Jeffrey/E-4380-2011; OI Eastman, Jeff/0000-0002-0847-4265 NR 16 TC 76 Z9 79 U1 1 U2 21 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD MAY-JUN PY 1997 VL 8 IS 3 BP 243 EP 252 DI 10.1016/S0965-9773(97)00167-0 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA XA594 UT WOS:A1997XA59400001 ER PT J AU Owens, TJ Zandt, G AF Owens, TJ Zandt, G TI Implications of crustal property variations for models of Tibetan plateau evolution SO NATURE LA English DT Article ID BENEATH SOUTHERN TIBET; MANTLE VELOCITIES; DEEP-STRUCTURE; SHEAR; CONSTRAINTS; PROPAGATION; ANISOTROPY; HIMALAYAS; THICKNESS; UPLIFT AB Shear-coupled teleseismic P waves sampling the interior of the Tibetan plateau provide evidence of systematic variations in crustal structure. The crust thins by up to 20 km from south to north with a concomitant increase in Poisson's ratio from normal values in the south to unusually high values in the north. This Suggests that the crust of the northern plateau is partially melted due to high temperatures. These changes imply spatial and perhaps temporal variations in the way the elevation of the high plateau is created and maintained. C1 UNIV ARIZONA,DEPT GEOSCI,TUCSON,AZ 85721. LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. RP Owens, TJ (reprint author), UNIV S CAROLINA,DEPT GEOL SCI,COLUMBIA,SC 29208, USA. NR 48 TC 381 Z9 449 U1 4 U2 49 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD MAY 1 PY 1997 VL 387 IS 6628 BP 37 EP 43 DI 10.1038/387037a0 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WW758 UT WOS:A1997WW75800040 ER PT J AU Smith, DJ Stevens, ME Sudanagunta, SP Bronson, RT Makhinson, M Watabe, AM ODell, TJ Fung, J Weier, HUG Cheng, JF Rubin, EM AF Smith, DJ Stevens, ME Sudanagunta, SP Bronson, RT Makhinson, M Watabe, AM ODell, TJ Fung, J Weier, HUG Cheng, JF Rubin, EM TI Functional screening of 2 Mb of human chromosome 21q22.2 in transgenic mice implicates minibrain in learning defects associated with Down's syndrome SO NATURE GENETICS LA English DT Article ID LONG-TERM POTENTIATION; GAMMA-MUTANT MICE; CGMP-PHOSPHODIESTERASE; BETA-SUBUNIT; RD MOUSE; HIPPOCAMPAL; GENE; GENERATION; DISRUPTION; DEFICITS AB Using Down syndrome as a model for complex trait analysis, we sought to identify loci from chromosome 21q22.2 which, when present in an extra dose, contribute to learning abnormalities. We generated low-copy-number transgenic mice, containing four different yeast artificial chromosomes (YACs) that together cover approximately 2 megabases (Mb) of contiguous DNA from 21q22.2. We subjected independent lines derived from each of these YAC transgenes to a series of behavioural and learning assays. Two of the four YACs caused defects in learning and memory in the transgenic animals, while the other two YACs had no effect. The most severe defects were caused by a 570-kb YAC; the interval responsible for these defects was narrowed to a 180-kb critical region as a consequence of YAC fragmentation, This region contains the human homologue of a Drosophila gene, minibrain, and strongly implicates it in learning defects associated with Down syndrome. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR HUMAN GENOME,BERKELEY,CA 94720. TUFTS UNIV,SCH MED,USDA,HUMAN NUTR RES CTR AGING,BOSTON,MA 02111. TUFTS UNIV,SCH VET MED,BOSTON,MA 02111. JACKSON LAB,BAR HARBOR,ME 04609. UNIV CALIF LOS ANGELES,SCH MED,DEPT PHYSIOL,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,SCH MED,BRAIN RES INST,LOS ANGELES,CA 90024. FU NHLBI NIH HHS [HL18574] NR 46 TC 225 Z9 230 U1 0 U2 5 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1061-4036 J9 NAT GENET JI Nature Genet. PD MAY PY 1997 VL 16 IS 1 BP 28 EP 36 DI 10.1038/ng0597-28 PG 9 WC Genetics & Heredity SC Genetics & Heredity GA WX024 UT WOS:A1997WX02400019 PM 9140392 ER PT J AU Robbins, WA Meistrich, ML Moore, D Hagemeister, FB Weier, HU Cassel, MJ Wilson, G Eskenazi, B Wyrobek, AJ AF Robbins, WA Meistrich, ML Moore, D Hagemeister, FB Weier, HU Cassel, MJ Wilson, G Eskenazi, B Wyrobek, AJ TI Chemotherapy induces transient sex chromosomal and autosomal aneuploidy in human sperm SO NATURE GENETICS LA English DT Article ID FLUORESCENCE INSITU HYBRIDIZATION; IN-SITU HYBRIDIZATION; HODGKINS-DISEASE; RADIOTHERAPY; ABERRATIONS; CYCLOPHOSPHAMIDE; NONDISJUNCTION; ABNORMALITIES; VINCRISTINE; PREDNISONE AB Each year more than 20,000 children and young persons of reproductive age are exposed to known mutagens in the form of chemo- and/or radiotherapy for cancer in the States(1,2). As more of these treatments are effective there is growing concern that genetic defects are introduced in the germ cells of these young patients, It is well documented for male rodents that treatment with chemo- and radio-therapeutic agents before mating can cause genetic damage in the germ line(3-10), and the magnitude of heritable effects depends on the spermatogenic cell stage treated, Similar germinal effects are suspected to occur in humans but remain unproven(11-15), Hodgkin's disease (HD) is an example of a malignancy which is typically diagnosed during a patient's reproductive years, In our study we observed eight male HD patients who were treated with NOVP (Novanthrone, Oncovin, Vinblastine, Prednisone) chemotherapy, We evaluated sperm aneuploidy using multi-colour fluorescence in situ hybridization (FISH), and found similar to 5-fold increases in sperm with disomies, diploidies and complex genotypes involving chromosome X,Y and 8, Increases in sex chromsome aneuploidies arose from segregation errors at meiosis I as well as meiosis II, The aneuploidy effects were transient, however, declining to pretreatment levels within approximately 100 days after the end of the therapy, When compared with normal men, some HD patients showed higher proportions of certain sperm aneupolidy types even before their first therapy. C1 LAWRENCE LIVERMORE NATL LAB, BIOL & BIOTECHNOL RES PROGRAM, LIVERMORE, CA 94551 USA. UNIV CALIF BERKELEY, SCH PUBL HLTH, EPIDEMIOL GRP, BERKELEY, CA 94720 USA. UNIV TEXAS, MD ANDERSON CANCER CTR, DEPT EXPT RADIAT ONCOL, HOUSTON, TX 77030 USA. UNIV TEXAS, MD ANDERSON CANCER CTR, DEPT HEMATOL, HOUSTON, TX 77030 USA. LAWRENCE BERKELEY LAB, DIV LIFE SCI, BERKELEY, CA 94720 USA. NR 41 TC 151 Z9 155 U1 1 U2 3 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 1061-4036 J9 NAT GENET JI Nature Genet. PD MAY PY 1997 VL 16 IS 1 BP 74 EP 78 DI 10.1038/ng0597-74 PG 5 WC Genetics & Heredity SC Genetics & Heredity GA WX024 UT WOS:A1997WX02400025 PM 9140398 ER PT J AU Cao, YZ Krogstad, P Korber, BT Koup, RA Muldoon, M Macken, C Song, JL Jin, ZQ Zhao, JQ Clapp, S Chen, ISY Ho, DD Ammann, AJ Mullins, J Walker, B Wolinsky, S Bardeguez, A Crane, M Hanson, C Hamill, H Luzuriaga, K Palumbo, P VanDyke, R Widmayer, S Wiznia, A AF Cao, YZ Krogstad, P Korber, BT Koup, RA Muldoon, M Macken, C Song, JL Jin, ZQ Zhao, JQ Clapp, S Chen, ISY Ho, DD Ammann, AJ Mullins, J Walker, B Wolinsky, S Bardeguez, A Crane, M Hanson, C Hamill, H Luzuriaga, K Palumbo, P VanDyke, R Widmayer, S Wiznia, A TI Maternal HIV-1 viral load and vertical transmission of infection: The Ariel Project for the Prevention of HIV Transmission from Mother to Infant SO NATURE MEDICINE LA English DT Article ID HUMAN-IMMUNODEFICIENCY-VIRUS; TO-CHILD TRANSMISSION; TYPE-1; QUANTITATION AB Most HIV-1 infections of children result from mother-to-infant transmission, which may occur perinatally or postnatally, as a consequence of breast feeding(1-8). In this study, the influence of maternal viral load on transmission of infection to infants from non-breast-feeding mothers was examined using samples of plasma and peripheral blood mononuclear cells (PBMCs) collected at several time points during pregnancy and the 6-month period after delivery. These samples were analyzed by several quantitative methods, including virus cultures of PBMCs and polymerase chain reaction (PCR) assays for HIV-1 RNA in plasma and DNA in PBMCs. The risk of transmission increased slightly with a higher viral load, but transmission and nontransmission occurred over the entire range of values for each assay. No threshold value of virus load was identified which discriminated between transmitters and nontransmitters. We also noted a significant rise in viral load and a decline in CD4(+) lymphocytes in the six months after delivery. These findings suggest that a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Additional studies are needed to examine the post-partum increase in viremia. C1 ROCKEFELLER UNIV,AARON DIAMOND AIDS RES CTR,NEW YORK,NY 10016. UNIV CALIF LOS ANGELES,SCH MED,DEPT PEDIAT,LOS ANGELES,CA 90024. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. SANTA FE INST,SANTA FE,NM 87501. UNIV MANCHESTER,INST SCI & TECHNOL,DEPT MATH,MANCHESTER M60 1QD,LANCS,ENGLAND. UNIV CALIF LOS ANGELES,SCH MED,DEPT MED,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,SCH MED,DEPT MICROBIOL & IMMUNOL,LOS ANGELES,CA 90024. PEDIAT AIDS FDN,SANTA MONICA,CA. RI Muldoon, Mark/C-7505-2009; Wolinsky, Steven/B-2893-2012; OI Muldoon, Mark/0000-0002-5004-7195 NR 19 TC 143 Z9 146 U1 0 U2 0 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1078-8956 J9 NAT MED JI Nat. Med. PD MAY PY 1997 VL 3 IS 5 BP 549 EP 552 DI 10.1038/nm0597-549 PG 4 WC Biochemistry & Molecular Biology; Cell Biology; Medicine, Research & Experimental SC Biochemistry & Molecular Biology; Cell Biology; Research & Experimental Medicine GA WX543 UT WOS:A1997WX54300036 PM 9142125 ER PT J AU Moghaddam, MF Grant, DF Cheek, JM Greene, JF Williamson, KC Hammock, BD AF Moghaddam, MF Grant, DF Cheek, JM Greene, JF Williamson, KC Hammock, BD TI Bioactivation of leukotoxins to their toxic diols by epoxide hydrolase SO NATURE MEDICINE LA English DT Article ID RESPIRATORY-DISTRESS SYNDROME; BURN TOXIN; INDUCTION; INJURY; LIVER; RAT; 9,10-EPOXY-12-OCTADECENOATE; BIOSYNTHESIS; GLUTATHIONE; EXPRESSION AB Leukotoxin is a linoleic acic oxide produced by leukocytes and has been associated with the multiple organ failure and adult respiratory distress syndrome seen in some severe burn patients. Leukotoxin has been reported to be toxic when injected into animals intravenously. Herein, we report that this lipid is not, directly cytotoxic in at least two in vitro systems. Using a baculovirus expression system we demonstrate that leukotoxin is only cytotoxic in the presence of epoxide hydrolases. In addition, it is the diol metabolite that proves toxic to pulmonary alveolar epithelial cells, suggesting a critical role for the diol in leukotoxin-associated respiratory disease, In vivo data also support the toxicity of leukotoxin diol. For the first time we demonstrate that soluble epoxide hydrolase can bioactivate epoxides to diols that are apparently cytotoxic. Thus leukotoxin should be regarded as a protoxin corresponding to the more toxic diol. This clearly has implications for designing new clinical interventions. C1 LAWRENCE LIVERMORE NATL LAB,DEPT ENTOMOL,DAVIS,CA 95616. LAWRENCE LIVERMORE NATL LAB,DEPT ENVIRONM TOXICOL,DAVIS,CA 95616. LAWRENCE LIVERMORE NATL LAB,DEPT VET ANAT PHYSIOL & CELL BIOL,DAVIS,CA 95616. DUPONT AGR PROD,EXPT STN,WILMINGTON,DE 19880. UNIV ARKANSAS MED SCI HOSP,DEPT PHARMACOL & TOXICOL,LITTLE ROCK,AR 72205. FU NIEHS NIH HHS [ES02710, ES04699, ES05707] NR 32 TC 155 Z9 158 U1 0 U2 11 PU NATURE PUBLISHING CO PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 SN 1078-8956 J9 NAT MED JI Nat. Med. PD MAY PY 1997 VL 3 IS 5 BP 562 EP 566 DI 10.1038/nm0597-562 PG 5 WC Biochemistry & Molecular Biology; Cell Biology; Medicine, Research & Experimental SC Biochemistry & Molecular Biology; Cell Biology; Research & Experimental Medicine GA WX543 UT WOS:A1997WX54300039 PM 9142128 ER PT J AU Chapline, G AF Chapline, G TI Spontaneous origin of topological complexity in self-organizing neural networks SO NETWORK-COMPUTATION IN NEURAL SYSTEMS LA English DT Article ID VORTICES; SYSTEMS; CORTEX; STATE AB Attention is drawn to the possibility that self-organizing biological neural networks could spontaneously acquire the capability to carry out sophisticated computations. In particular, it is shown that the effective action governing the organization of feature detectors in neural networks which incorporate Kohonen-like self-organization can spontaneously lead to structures that are topologically non-trivial in both a two- and a four-dimensional sense. It is suggested that the appearance of biological neural structures with a non-trivial four-dimensional topology is the fundamental organizational development underlying the advanced cognitive capabilities of the mammalian brain. RP Chapline, G (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 29 TC 1 Z9 1 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0954-898X J9 NETWORK-COMP NEURAL JI Netw.-Comput. Neural Syst. PD MAY PY 1997 VL 8 IS 2 BP 185 EP 194 DI 10.1088/0954-898X/8/2/005 PG 10 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic; Neurosciences SC Computer Science; Engineering; Neurosciences & Neurology GA XC469 UT WOS:A1997XC46900005 ER PT J AU Ueki, K Ramaswamy, S Billings, SJ Mohrenweiser, HW Louis, DN AF Ueki, K Ramaswamy, S Billings, SJ Mohrenweiser, HW Louis, DN TI ANOVA, a putative astrocytic RNA-binding protein gene that maps to chromosome 19q13.3 SO NEUROGENETICS LA English DT Article DE chromosome 19; glioma; NOVA; RNA-binding ID TUMOR-SUPPRESSOR GENE; FRAGILE-X SYNDROME; EXON AMPLIFICATION; ANTI-RI; REGION; 19Q; IDENTIFICATION; ANTIBODIES; EXPRESSION; CLONING AB Exon amplification from cosmids mapping to the glioma tumor suppressor gene candidate region on chromosome 19q13.3 yielded an exon with high homology to a portion of the NOVA1 gene, which encodes a neuron-specific RNA-binding protein recognized by the paraneoplastic syndrome antibody anti-Ri. Screening of a human brain cDNA library with this exon identified a 1.9 kb cDNA with extensive homology to NOVA1, including three nearly identical KH domains characteristic of a subtype of RNA-binding proteins. Northern blots demonstrated expression of a 2.5 kb mRNA in brain, but in no other tissues. In situ hybridization on human cerebral cortex showed mRNA expression restricted to astrocytes. We have therefore named the gene ANOVA, for astrocytic NOVA1-like gene. Southern blotting and single strand conformation polymorphism analyses did not show tumor-specific alterations of this gene in gliomas and RT-PCR studies showed expression in glioma cell lines, suggesting that ANOVA is not the chromosome 19q glioma tumor suppressor gene. Given that two cloned paraneoplastic antigens are neuronal RNA-binding proteins and that glial proteins may act as paraneoplastic antigens, the ANOVA product may be a target antigen in one of the undefined human paraneoplastic syndromes. C1 Massachusetts Gen Hosp, Mol Neurooncol Lab, Dept Pathol Neuropathol & Neurosurg Serv, Charlestown, MA 02129 USA. Harvard Univ, Sch Med, Charlestown, MA 02129 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Human Genome, Livermore, CA 94550 USA. RP Louis, DN (reprint author), Massachusetts Gen Hosp, Mol Neurooncol Lab, Dept Pathol Neuropathol & Neurosurg Serv, Charlestown, MA 02129 USA. FU NCI NIH HHS [CA 69285] NR 28 TC 11 Z9 12 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1364-6745 J9 NEUROGENETICS JI Neurogenetics PD MAY PY 1997 VL 1 IS 1 BP 31 EP 36 DI 10.1007/s100480050005 PG 6 WC Genetics & Heredity; Clinical Neurology SC Genetics & Heredity; Neurosciences & Neurology GA 135ZP UT WOS:000076833200006 PM 10735272 ER PT J AU Coskun, E Kwong, MK AF Coskun, E Kwong, MK TI Simulating vortex motion in superconducting films with the time-dependent Ginzburg-Landau equations SO NONLINEARITY LA English DT Article ID II SUPERCONDUCTORS; FIELD; MODEL AB The time-dependent Ginzburg-Landau equations (TDGL) model a thin-film superconductor of finite size placed under a magnetic field. For numerical computation, we use a staggered grid discretization, a technique well known in numerical fluid mechanics. Some properties of the solutions are established. An efficient explicit-implicit method based on the forward Euler method is developed. In our simulations, we impose natural boundary conditions at the edge of the superconductor. With suitable choices of parameters (corresponding to physical superconductors of type II) and the strength of the external magnetic field, the steady-state solutions exhibit vortices. When a variable strength magnetic field, simulating a transient current, is introduced, we observe motion of the vortices in a periodic pattern. C1 ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. RP Coskun, E (reprint author), KARADENIZ TECH UNIV,DEPT MATH,TR-61080 TRABZON,TURKEY. NR 27 TC 18 Z9 18 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0951-7715 J9 NONLINEARITY JI Nonlinearity PD MAY PY 1997 VL 10 IS 3 BP 579 EP 593 DI 10.1088/0951-7715/10/3/001 PG 15 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA WZ938 UT WOS:A1997WZ93800001 ER PT J AU Helton, JC Trauth, KM AF Helton, JC Trauth, KM TI Comments on an evaluation of the 1992 performance assessment for the Waste Isolation Pilot Plant SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article ID EPA RELEASE LIMITS; NATURAL-WATERS; MINERAL SOLUBILITIES; UNCERTAINTY; HYDROLYSIS; DISPOSAL; SYSTEM; THERMODYNAMICS; 25-DEGREES-C; NEPTUNIUM(V) AB The following topics are discussed in a review of the 1992 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP): (1) inclusion of potash mining and other disruptions in the definition of possible futures at the WIPP, (2) definition of future drilling rates in the vicinity of the WIPP, (3) possible non-conservatisms in analysis assumptions, (4) characterization of uncertainty in solubilities, and (5) characterization of uncertainty in distribution coefficients. With respect to (1) and (2), the 1992 WIPP PA attempted to follow guidance in the US Environmental Protection Agency's (EPA's) standard for the geological disposal of radioactive waste, 40 CFR 191. Many of the reviewer's comments relate to the EPA's recent guidance in 40 CFR 194 on assessing compliance with 40 CFR 191, which was not published until early 1996 and which makes many changes from the guidance given in 40 CFR 191. The 1996 WIPP PA, which will support a compliance certification application to the EPA, will follow the guidance in 40 CFR 194. With respect to (3), (4) and (5), the WIPP PA tries to avoid both deliberate conservatism and deliberate non-conservatism. The 1992 WIPP PA attempted to use all the information available to it consistent with the requirements to incorporate uncertainty in PA results and to use 'reasonable expectation' as the criterion for assessing compliance with 40 CFR 191. Since 1992, many additional results related to solubilities and distribution coefficients have become available. The 1996 WIPP PA will incorporate these new results. (C) 1997 Elsevier Science S.A. C1 ARIZONA STATE UNIV,DEPT MATH,TEMPE,AZ 85287. RP Helton, JC (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 79 TC 2 Z9 2 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD MAY PY 1997 VL 168 IS 1-3 BP 339 EP 360 DI 10.1016/S0029-5493(96)01359-3 PG 22 WC Nuclear Science & Technology SC Nuclear Science & Technology GA XF272 UT WOS:A1997XF27200028 ER PT J AU Menard, JE Jardin, SC Kaye, SM Kessel, CE Manickam, J AF Menard, JE Jardin, SC Kaye, SM Kessel, CE Manickam, J TI Ideal MHD stability limits of low aspect ratio tokamak plasmas SO NUCLEAR FUSION LA English DT Article ID BOOTSTRAP CURRENT; TRANSPORT; MODES AB The ideal magnetohydrodynamic (MHD) stability limits of low aspect ratio tokamak plasmas are computed numerically for plasmas with a range of cylindrical safety factors q*, normalized plasma pressures beta, elongations kappa and central safety factors q(0). Four distinct regimes are optimized, namely: (a) low-q* plasmas with q(0) = 1.1 with and without a stabilizing wall, (b) low-q* plasmas with no wall and 1.1 < q(0) < 2, (c) high-beta, high bootstrap fraction plasmas at moderate kappa requiring a wall and edge current drive and (d) high-beta, very high bootstrap fraction plasmas with moderate to high kappa requiring a stabilizing wall but little external current drive. A stable equilibrium is found at an aspect ratio of A = 1.4 and an elongation of kappa = 3.0, with 99.3% of the current provided by the plasma pressure and beta = 45%. Special attention is paid to the issues of numerical convergence and the proper definition of bootstrap current fraction. RP Menard, JE (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Jardin, Stephen/E-9392-2010; OI Menard, Jonathan/0000-0003-1292-3286 NR 30 TC 85 Z9 85 U1 0 U2 1 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAY PY 1997 VL 37 IS 5 BP 595 EP 610 DI 10.1088/0029-5515/37/5/I03 PG 16 WC Physics, Fluids & Plasmas SC Physics GA XP373 UT WOS:A1997XP37300003 ER PT J AU Cohen, RH Ryutov, DD AF Cohen, RH Ryutov, DD TI Plasma convection induced by toroidal asymmetries of the divertor plates and gas puffing SO NUCLEAR FUSION LA English DT Article ID MAGNETIC-FIELD AB In the open field line region of the scrape-off layer (SOL), the plasma potential is to a considerable degree determined by the boundary conditions on the divertor plates. The idea is explored here that, by making the divertor plates slightly 'wavy' in the toroidal direction, toroidally varying potentials can be produced throughout the SOL and thereby convective plasma motion induced. This motion should lead to a broadening of the SOL and to a reduction of the heat load on the divertor plates. An attractive feature of this technique is that it induces strong convection only on the open field lines without causing enhanced transport inside the separatrix. The possibility is also considered of inducing plasma convection by varying the composition of the divertor plate in the toroidal and radial directions, so as to affect the plasma potential by virtue of the toroidal variation of the secondary emission coefficient. Mutual biasing of adjacent elements of the plates is the third option. Finally, the use of toroidally asymmetric gas puffing to induce toroidal asymmetry in the potential distribution is discussed. C1 LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. NR 13 TC 37 Z9 37 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 MAY PY 1997 VL 37 IS 5 BP 621 EP 627 DI 10.1088/0029-5515/37/5/I05 PG 7 WC Physics, Fluids & Plasmas SC Physics GA XP373 UT WOS:A1997XP37300005 ER PT J AU Park, HK Sabbagh, SA AF Park, HK Sabbagh, SA TI Effect of the neutral beam fuelling profile on fusion power, confinement and stability in TFTR SO NUCLEAR FUSION LA English DT Article ID TOKAMAK ENERGY CONFINEMENT; DIII-D TOKAMAK; TEST-REACTOR; TRITIUM; DEUTERIUM; PLASMAS; SUPERSHOTS; TRANSPORT; PERFORMANCE; SIMULATIONS AB The stored energy and neutron yields of TFTR plasmas have been modelled, with small dispersion, by considering a parameter associated with the peakedness of the beam fuelling profile as an independent variable. Scalings with fixed multiplicative constants and exponential powers determined from the experimental data are applied to deuterium discharges at different major radii in TFTR, and also to deuterium-tritium (DT) plasmas. The domain of the data considered includes the supershot, high poloidal beta, I; mode and limiter H mode operational regimes, as well as discharges with a reversed shear (RS) magnetic configuration. The role of plasma parameters, such as plasma current I-p, edge safety factor q(a) and toroidal field B-t, are considered in this study. Improved energy confinement and neutron production are relatively insensitive to these parameters compared with the beam fuelling peakedness parameter when considering plasmas that are stable to magnetohydrodynamic modes. In contrast, plasma stability is dependent on these quantities and also on parameters describing the peakedness of the equilibrium profiles. On the basis of externally controllable plasma parameters, the limitation and optimization of fusion power production of the present TFTR is investigated and a path towards a discharge condition with fusion power gain Q > 1 is suggested. C1 COLUMBIA UNIV,DEPT APPL PHYS,NEW YORK,NY 10027. RP Park, HK (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Sabbagh, Steven/C-7142-2011 NR 40 TC 4 Z9 4 U1 0 U2 5 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAY PY 1997 VL 37 IS 5 BP 629 EP 642 DI 10.1088/0029-5515/37/5/I06 PG 14 WC Physics, Fluids & Plasmas SC Physics GA XP373 UT WOS:A1997XP37300006 ER PT J AU Giruzzi, G Barbato, E Bernabei, S Cardinali, A AF Giruzzi, G Barbato, E Bernabei, S Cardinali, A TI Measurement of the hot electrical conductivity in the PBX-M tokamak SO NUCLEAR FUSION LA English DT Article ID CURRENT-DRIVE EXPERIMENTS; HYBRID CURRENT DRIVE; DIII-D TOKAMAK; CURRENT PROFILE; PLASMA; RESISTIVITY; WAVES; MODEL; BETA AB A new method for the analysis of tokamak discharges in which the plasma current is driven by a combination of high power RF waves and a DC electric field is presented. In such regimes, which are the most usual in RF current drive experiments, it is generally difficult to separate the different components of the plasma current, i.e. purely ohmic, purely non-inductive and cross-terms. If the bilinear (in wave power and electric field) cross-term is the dominant one, an explicit relation between the loop voltage drop and the injected power can be found. This relation involves two parameters, the purely RF current drive efficiency and the hot (power dependent) electrical conductivity. These can be simultaneously determined from a simple two parameter ht, if the loop voltage drop is measured at several RF power levels. An application to lower hybrid current drive experiments in the Princeton Beta Experiment (PBX-M) tokamak is presented. It is shown that the method also allows independent evaluation of the average power absorption fraction and the nil upshift. C1 EURATOM, ENEA FUS, CTR RIC ENERGIA FRASCATI, FRASCATI, ITALY. PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, PRINCETON, NJ 08543 USA. RP Giruzzi, G (reprint author), EURATOM, CEA FUS, DEPT RECH FUS CONTROLEE, CEA CADARACHE, ST PAUL LES DURANCE, FRANCE. NR 24 TC 36 Z9 37 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 MAY PY 1997 VL 37 IS 5 BP 673 EP 680 DI 10.1088/0029-5515/37/5/I09 PG 8 WC Physics, Fluids & Plasmas SC Physics GA XP373 UT WOS:A1997XP37300009 ER PT J AU Hogan, JT Bush, CE Skinner, CH AF Hogan, JT Bush, CE Skinner, CH TI Lithium effects in plasmas - Report on the Workshop held at Princeton, New Jersey, United States of America, 17-18 October 1996 SO NUCLEAR FUSION LA English DT Editorial Material C1 PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Hogan, JT (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37830, USA. NR 1 TC 17 Z9 17 U1 5 U2 5 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5, PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD MAY PY 1997 VL 37 IS 5 BP 705 EP 711 DI 10.1088/0029-5515/37/5/413 PG 7 WC Physics, Fluids & Plasmas SC Physics GA XP373 UT WOS:A1997XP37300013 ER PT J AU Abrams, GS Ashmanskas, W Bintinger, D Ciocio, S Hoff, M Kadel, RW Kadyk, J Minamihara, Y Lim, A Long, M Pope, W Pripstein, M Przybylski, G Thur, W Weber, T Yarba, J Hearty, C Amadon, A Bonamy, P Bystricky, J Ernwein, J Glicenstein, JF Hubbard, JR LeDu, P Reymond, JM Rondeaux, F Villet, G Singh, V Bhatti, A Melese, P Hauser, J Lindgren, M Muller, T Cushman, P Rusack, R AF Abrams, GS Ashmanskas, W Bintinger, D Ciocio, S Hoff, M Kadel, RW Kadyk, J Minamihara, Y Lim, A Long, M Pope, W Pripstein, M Przybylski, G Thur, W Weber, T Yarba, J Hearty, C Amadon, A Bonamy, P Bystricky, J Ernwein, J Glicenstein, JF Hubbard, JR LeDu, P Reymond, JM Rondeaux, F Villet, G Singh, V Bhatti, A Melese, P Hauser, J Lindgren, M Muller, T Cushman, P Rusack, R TI Test beam results for an endcap electromagnetic calorimeter for the SSC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We have tested a calorimeter test beam module intended to simulate the endcap electromagnetic calorimeter of the Solenoidal Detector Collaboration (SDC) experiment at the SSC. The test module is manufactured from scintillating tiles and is read out via 1 mm diameter wavelength shifting fibers with shower sampling at similar to 1 radiation length intervals. The results of test beam calibration show that the calorimeter is linear to within 1% and has a resolution of (19.5 +/- 0.1)%/root E + (0.47% +/- 0.05)% for energies up to 200 GeV. Test beam data show that non-uniform, longitudinal radiation damage to the calorimeter (up to similar to 50% light loss at shower maximum) can be corrected, and the original linearity of the calorimeter can be recovered with only a small degradation of resolution. A ''pre-shower detector'' improves the charged pi rejection by a factor of 2-3 at an electron detection efficiency greater than 97.5 +/- 0.3%. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV PHYS,BERKELEY,CA 94720. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV BRITISH COLUMBIA,VANCOUVER,BC V6T 1Z1,CANADA. CEA SACLAY,DAPNIA,SPP,F-91191 GIF SUR YVETTE,FRANCE. AT&T BELL LABS,HOLMDEL,NJ 07733. ROCKEFELLER UNIV,NEW YORK,NY 10021. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV MINNESOTA,DEPT PHYS,MINNEAPOLIS,MN 55455. 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 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1997 VL 390 IS 1-2 BP 41 EP 62 DI 10.1016/S0168-9002(97)00381-1 PG 22 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ496 UT WOS:A1997XJ49600006 ER PT J AU Greenwood, RC Helmer, RG Putnam, MH AF Greenwood, RC Helmer, RG Putnam, MH TI Measurement of beta(-)-decay intensity distributions of several fission-product isotopes using a total absorption gamma-ray spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID BETA-DECAY; CS-140 AB A total absorption gamma-ray spectrometer coupled to the Cf-252-based INEL ISOL facility has been used in a program of systematic study of the distributions of (beta-)-decay intensities of fission-product radionuclides. Cascade-summed gamma-ray spectra measured with the system have been compared with the spectrum simulated from the corresponding decay schemes, as a test of the completeness and correctness of these schemes. New (beta-)-decay intensity distributions have been deduced for the decay of these radionuclides. Radionuclides which have been studied in this manner include Rb-89, Rb-90g, Rb-90m, Rb-91, Rb-93, Sr-93, Sr-94, Y-94, Sr-95, Y-95, Cs-138g, Cs-138m, Cs-139, Cs-140, Cs-141, Ba-141, Ba-142, La-142, Ba-143, La-143, Ba-144, La-144, Ba-145, La-145, Ce-145, Ce-146, Pr-146, Ce-147, Pr-147, Ce-148, Pr-148(2.0 min), Pr-148(2.27 min), Pr-149, Nd-149, Pr-151, Nd-151, Nd-152- Pm-152(4.1 min.), Nd-153, Pm-153, Nd-154, Pm-154(1.7 min), Nd-155, Pm-155, Pm-156, Pm-157, Sm-157, Sm-158, and Eu-158. C1 UNIV IDAHO,DEPT PHYS,MOSCOW,ID 83844. IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. NR 51 TC 60 Z9 61 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1997 VL 390 IS 1-2 BP 95 EP 154 DI 10.1016/S0168-9002(97)00356-2 PG 60 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ496 UT WOS:A1997XJ49600010 ER PT J AU Shao, YP Cherry, SR Siegel, S Silverman, RW Majewski, S AF Shao, YP Cherry, SR Siegel, S Silverman, RW Majewski, S TI Evaluation of multi-channel PMTs for readout of scintillator arrays SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID POSITION-SENSITIVE PHOTOMULTIPLIERS; DETECTOR; FIBERS AB We have evaluated two Philips multi-channel photomultiplier tubes (MC-PMTs) as position-sensitive photon detectors for reading out small scintillator arrays. The 64 channel XP1702 MC-PMT has a standard glass entrance window while the XP1722 model has a fibre-optic entrance window designed to reduce inter-channel crosstalk. Scientillator arrays are coupled typically to these MC-PMTs using optical fibers. In this paper, we present measurements of inter-channel gain variation, pixel-to-pixel crosstalk, single photoelectron spectra, MC-PMT linearity and sensitivity to magnetic fields. For both the XP1702 and XP1722 models, the maximum-gain variation over all 64 channels is typically 3:1, while the difference between any two adjacent channels is less than 2:1. Crosstalk to the nearest neighbor is 10% for the fiber-optic input window tube compared with 20% for the glass input window tube and is relatively insensitive to the size and numerical aperture of the optical fiber used. The output of the 10th dynode (position signal) remains linear up to 400 photoelectrons at a gain of 4 x 10(6) using a Philips VD107 voltage divider. Performance in a magnetic field was found to depend strongly on the orientation of the tube relative to the field. Images obtain with a 511 keV source irradiating an 8 x 8 array of 2 x 2 x 10 mm BGO crystals coupled by optical fiber to these tubes show excellent crystal identification, particularly using the XP1722 MC-PMT. C1 THOMAS JEFFERSON NATL ACCELERATOR FAC,NEWPORT NEWS,VA. RP Shao, YP (reprint author), UNIV CALIF LOS ANGELES,CRUMP INST BIOL IMAGING,DEPT MOL & MED PHARMACOL,JLNRC,ROOM A222,LOS ANGELES,CA 90095, USA. NR 12 TC 10 Z9 10 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 MAY 1 PY 1997 VL 390 IS 1-2 BP 209 EP 218 DI 10.1016/S0168-9002(97)00379-3 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ496 UT WOS:A1997XJ49600019 ER PT J AU Holroyd, RA Itoh, K Nishikawa, M AF Holroyd, RA Itoh, K Nishikawa, M TI Mobility of excess electrons in hexamethyldisiloxane and bis(trimethylsilyl)methane SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID LIQUIDS; TRANSPORT; YIELDS AB The mobility of excess electrons in bis(trimethylsilyl)methane is 63 cm(2)/Vs, and in hexamethyldisiloxane 22 cm(2)/Vs. these and related silicon-containing compounds, the mobility is greater than for those alkanes which have comparable free-ion yields. C1 UNIV TOKYO, DEPT PURE & APPL SCI, TOKYO 153, JAPAN. KANAGAWA INST TECHNOL, FAC ENGN, ATSUGI, KANAGAWA 24302, JAPAN. RP Holroyd, RA (reprint author), BROOKHAVEN NATL LAB, DEPT CHEM, POB 5000, UPTON, NY 11973 USA. NR 15 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 1 PY 1997 VL 390 IS 1-2 BP 233 EP 236 DI 10.1016/S0168-9002(97)89463-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ496 UT WOS:A1997XJ49600021 ER PT J AU Gramegna, G OConnor, P Rehak, P Hart, S AF Gramegna, G OConnor, P Rehak, P Hart, S TI CMOS preamplifier for low-capacitance detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID LOW-NOISE AB We present a new CMOS preamplifier and shaper, optimized for charge measurements with detectors of 0.1-1 pF capacitance. A self-adaptive biasing scheme with nonlinear pole-zero cancellation allows us to use an MOS device operated in the triode region as the DC feedback element while eliminating nonlinearity and sensitivity to supply, temperature, and process variations and accepting up to several mu A leakage current. The circuit is continuously sensitive and requires no external adjustments to set the feedback resistance. Secondary sources of noise are minimized subject to a power dissipation constraint. Implemented in a 1.2 mu m CMOS process, the preamplifier achieves an ENC of 35 e(-) + 58 e(-)/pF at 23 mu s shaping time at a power consumption of about 3.2 mW. The integrated preamp/shaper has 50 ns shaping lime and the ENC is 120 e(-). It has 0.3% nonlinearity over an input dynamic range of 0-5 fC. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. POLITECN BARI,BARI,ITALY. WAYNE STATE UNIV,DETROIT,MI 48202. NR 12 TC 38 Z9 40 U1 3 U2 5 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 MAY 1 PY 1997 VL 390 IS 1-2 BP 241 EP 250 DI 10.1016/S0168-9002(97)00390-2 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ496 UT WOS:A1997XJ49600023 ER PT J AU Prussin, S Holland, OW AF Prussin, S Holland, OW TI The role of dose and position on the concentration of residual point defects in as-implanted wafers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB As generated, point defects are subject to a relaxation process which results in an in situ annihilation of part of the generated point defect concentration. The surviving fraction, m, can be determined by comparing the doses required to achieve equal damage deposition for room temperature implants and implants at cryogenic temperatures. It was found that m exhibits a maximum in the implant midrange and decreases continuously with dose as the residual point defect concentration accumulates. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Prussin, S (reprint author), UNIV CALIF LOS ANGELES,DEPT ELECT ENGN,LAB POINT DEFECT ENGN,LOS ANGELES,CA 90095, USA. NR 12 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 18 EP 21 DI 10.1016/S0168-583X(97)00842-2 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500004 ER PT J AU Ishikawa, N Awaji, M Furuya, K Birtcher, RC Allen, CW AF Ishikawa, N Awaji, M Furuya, K Birtcher, RC Allen, CW TI HRTEM analysis of solid precipitates in Xe-implanted aluminum SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM DE solid Xe; implantation; precipitation; high-resolution electron microscopy; Moire patterns; tetradecahedral precipitates; off-Bragg illumination ID RESOLUTION ELECTRON-MICROSCOPY; ROOM-TEMPERATURE; LATTICE IMAGES; XENON; BUBBLES; KR; AL AB High-resolution transmission electron microscopy (HRTEM) was carried out to determine the shape and atomic arrangement of solid Xe precipitates in Al. Polycrystalline Al TEM specimens were implanted with 30 keV Xe+ at room temperature to a dose of 3 x 10(20) ions/m(2) and were subsequently annealed at 523 K. Below a size of approximately 4 nm in diameter, Xe precipitates are solid with an FCC crystal structure that are mesotacticly aligned with the Al lattice. In HRTEM along the [011] projection, the difference in the lattice parameters of solid Xe and Al produces a precipitate image dominated by a two-dimensional Moire pattern that repeats in both the [001] and [111] directions every 3 Al (or 2 Xe) lattice spacings, Multi-slice image simulations, using a three-dimensional atomic model, demonstrates that the precipitates are tetradecahedra with faces parallel to the dense {111} planes and the {100} planes, Off-Bragg illumination of the precipitates minimizes Al lattice fringes and generates precipitate images which are in good agreement with the model. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Ishikawa, N (reprint author), NATL RES INST MET,1-2-1 SENGEN,TSUKUBA,IBARAKI 305,JAPAN. NR 15 TC 32 Z9 32 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 123 EP 126 DI 10.1016/S0168-583X(96)00864-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500028 ER PT J AU Meldrum, A Boatner, LA Wang, LM Ewing, RC AF Meldrum, A Boatner, LA Wang, LM Ewing, RC TI Ion-beam-induced amorphization of LaPO4 and ScPO4 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID IRRADIATION-INDUCED AMORPHIZATION; MONAZITE; ZIRCON AB LaPO4 and ScPO4 were irradiated by a 1.5 MeV Kr+ ion beam using the HVEM-tandem Facility at Argonne National Laboratory. The ion-beam-induced amorphization was investigated over a temperature range of 20 to 570 K and the degree of amorphization was determined in-situ by monitoring the gradual loss of electron diffraction maxima, Subsequent high-resolution TEM analysis revealed the development of an amorphous phase. LaPO4 and ScPO4 were found to have activation energies for irradiation-enhanced annealing of 0.02 and 0.11 eV, attributed to diffusion-driven epitaxial recrystallization. The critical temperatures of amorphization were found to be 365 and 540 K, respectively. Both materials recrystallized under electron irradiation. These results suggest that the phosphates are generally less sensitive to ion-beam irradiation over a wide temperature range than are their silicate structure analogues and that the zircon structure-type has a higher energy barrier to recrystallization than the related monazite structure-type. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Meldrum, A (reprint author), UNIV NEW MEXICO,DEPT EARTH & PLANETARY SCI,ALBUQUERQUE,NM 87131, USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 27 TC 22 Z9 22 U1 2 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 160 EP 165 DI 10.1016/S0168-583X(96)00873-7 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500037 ER PT J AU Weber, WJ Yu, N AF Weber, WJ Yu, N TI In situ and ex situ investigation of ion-beam-induced amorphization in alpha-SiC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID IMPLANTED SILICON-CARBIDE; IRRADIATION-INDUCED CRYSTALLINE; AMORPHOUS TRANSITION; SINGLE-CRYSTALS; TEMPERATURE; DAMAGE AB Single crystals of alpha-SiC with [0001] orientation have been irradiated at 300 K with 360 keV Ar2+ ions at an incident angle of 25 degrees. The damage accumulation in one sample was followed in situ by Rutherford backscattering spectroscopy in channeling geometry (RBS/C) along the [<1(1)over bar 02>] direction until the aligned backscattering yield reached the random level throughout the irradiated layer at a fluence of 8 Ar2+ ions/nm(2). Six other samples were irradiated at fluences ranging from 1 to 6 Ar2+ ions/nm(2), and the damage accumulation was characterized ex situ by RBS/C along the [0001] direction. The relative disorder, as measured by RBS/C, increased with ion fluence; however, the observed rate of disordering was much lower when measured ex situ along the [0001] direction. C1 LOS ALAMOS NATL LAB, DIV MAT SCI & TECHNOL, LOS ALAMOS, NM 87545 USA. RP Weber, WJ (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. RI Weber, William/A-4177-2008 OI Weber, William/0000-0002-9017-7365 NR 26 TC 20 Z9 20 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 191 EP 194 DI 10.1016/S0168-583X(96)00883-X PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500043 ER PT J AU Fayeulle, S Torri, P Nastasi, M Lu, YC Kung, H Tesmer, JR AF Fayeulle, S Torri, P Nastasi, M Lu, YC Kung, H Tesmer, JR TI Ion beam induced modifications in dc sputtered TiN/B-C-N multilayers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID STRESS; FLOW AB The effects of Ar ion irradiation on the structure and stability of multilayered de sputtered thin films of TiN/B-C-N have been studied. Four phenomena are observed: interdiffusion between the layers, increase of the bilayer repeat length to a maximum of 12.8%, departure of nitrogen from the film and relaxation of the highly compressive stress initially present to small tensile stress. For the highest dose (5 x 10(16) ions/cm(2)) the multilayered structure partly disappears. Two regimes of diffusivity are detected. The various mechanisms are discussed in terms of viscous flow of atoms and of stress-controlled diffusion. C1 UNIV HELSINKI,HELSINKI,FINLAND. LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP Fayeulle, S (reprint author), ECOLE CENT LYON,LAB MAT MECAN PHYS,UMR CNRS 5621,F-69131 ECULLY,FRANCE. NR 16 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 198 EP 202 DI 10.1016/S0168-583X(96)00885-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500045 ER PT J AU Chason, E Kellerman, BK AF Chason, E Kellerman, BK TI Monte Carlo simulations of ion-enhanced island coarsening SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID EPITAXIAL-GROWTH; SUPPRESSION; SI(100) AB Monte Carlo simulations of growth and ion bombardment have been performed to explore the atomistic processes that occur during ion-assisted growth. The primary elements of the simulation are (1) creation of surface defects (vacancies and adatoms) by ion bombardment and deposition, (2) thermally activated motion of surface defects and (3) recombination of surface vacancies and adatoms, We find that a balance of ion bombardment and deposition (where the creation rate of adatom defects is equal to that of surface vacancies) leads to larger islands and more rapid island coarsening than thermal coarsening with no flux of defects, The presence of the defect flux enhances the breakup of clusters, leading to a broad distribution of island sizes. In comparison, thermal coarsening leads to a more uniform distribution of island sizes that increases in size much more slowly. Histograms of the evolution of the island size distribution provide a quantitative measure of the ion-induced increase in the rate of coarsening. C1 MEMC ELECT MAT,ST PETERS,MO. RP Chason, E (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 10 TC 19 Z9 19 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 225 EP 229 DI 10.1016/S0168-583X(96)00889-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500051 ER PT J AU Myers, SM Petersen, GA Headley, TJ Michael, JR Aselage, TL Seager, CH AF Myers, SM Petersen, GA Headley, TJ Michael, JR Aselage, TL Seager, CH TI Metal gettering by boron-silicide precipitates in boron-implanted silicon SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB We show that Fe, Co, Cu and Au impurities in Si are strongly gettered to boron-silicide precipitates formed by supersaturation boron implantation and annealing. Effective binding free energies relative to interstitial solution are extracted and range from about 1.2 to 2.2 eV. The B-Si precipitates formed at temperatures less than or equal to 1100 degrees C lack long range structural order but are similar to crystalline B3Si in composition and B chemical potential, Evidence indicates that the metal atoms go into solution in the B-Si phase, and this is interpreted in terms of the novel bonding and structural characteristics of B-rich icosahedral compounds. RP Myers, SM (reprint author), SANDIA NATL LABS,POB 5800,DEPT 1112,MAIL STOP 1056,ALBUQUERQUE,NM 87185, USA. NR 14 TC 13 Z9 13 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 291 EP 296 DI 10.1016/S0168-583X(96)00942-1 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500066 ER PT J AU Petersen, GA Myers, SM Follstaedt, DM AF Petersen, GA Myers, SM Follstaedt, DM TI Gettering of transition metals by cavities in silicon formed by helium ion implantation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID IMPURITIES; COPPER AB We have recently completed studies which quantitatively characterize the ability of nanometer-size cavities formed by He ion implantation to getter detrimental metal impurities in Si. Cavity microstructures formed in Si by ion implantation of He and subsequent annealing have been found to capture metal impurities by chemisorption on internal walls at low concentrations. Experiments utilizing ion-beam analysis, cross-sectional transmission electron microscopy, and secondary ion mass spectrometry were performed to quantitatively characterize the gettering effects and to determine the free energies associated with the chemisorbed metal atoms as a function of temperature. Mathematical models utilizing these results have been developed to predict the gettering behavior of cavities as compared to conventional gettering by precipitation. RP Petersen, GA (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 14 TC 36 Z9 36 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 301 EP 306 DI 10.1016/S0168-583X(96)00944-5 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500068 ER PT J AU Follstaedt, DM Myers, SM Floro, JA Lee, SR AF Follstaedt, DM Myers, SM Floro, JA Lee, SR TI Interaction of cavities with misfit dislocations in SiGe/Si heterostructures SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID SILICON AB Consequences of the strong, short-range attractive interaction between cavities and misfit dislocations are examined in SiGe/Si heterostructures. When He is implanted at the SiGe/Si interface, either in situ during epitaxial growth or by post-growth treatment, cavities form and locate on the misfit dislocation cores, The misfit dislocations are no longer straight lines extending over several microns, but form a network with jogs and intersections at the cavities. The He-implanted cavity layer enhances thermal relaxation of the strained alloy and may increase the achievable degree of relaxation by lowering dislocation energies. RP Follstaedt, DM (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 10 TC 5 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 375 EP 378 DI 10.1016/S0168-583X(96)00960-3 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500084 ER PT J AU Taylor, T Ila, D Zimmerman, RL Ashley, PR Poker, DB Hensley, DK AF Taylor, T Ila, D Zimmerman, RL Ashley, PR Poker, DB Hensley, DK TI Optical changes induced in GaAs/AlGaAs waveguides by MeV ion bombardment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID WAVE-GUIDES; IMPURITY AB We have fabricated optical channel waveguides in selectively masked planar GaAs/AlGaAs waveguide structures using MeV carbon and oxygen ions without post annealing. The fabricated channel waveguides were characterized exclusively by performing optical transmission measurements at a wavelength of 1.3 mu m Investigation of the extracted optical results reveals that further optimization of the ion beam parameters is required to reduce the observed propagation loss values. The feasibility of this technique may provide a totally new concept of localized optical modifications in the GaAs/AlGaAs system. C1 USA,MISSILE COMMAND,CTR RES DEV & ENGN,WEAPONS SCI DIRECTORATE,REDSTONE ARSENAL,AL 35898. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP Taylor, T (reprint author), ALABAMA A&M UNIV,DEPT PHYS,CTR IRRADIAT MAT,NORMAL,AL 35762, USA. RI Hensley, Dale/A-6282-2016 OI Hensley, Dale/0000-0001-8763-7765 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 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 442 EP 445 DI 10.1016/S0168-583X(96)00970-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500099 ER PT J AU Parikh, N Suvkhanov, A Lioubtchenko, M Carlson, E Bremser, M Bray, D Davis, R Hunn, J AF Parikh, N Suvkhanov, A Lioubtchenko, M Carlson, E Bremser, M Bray, D Davis, R Hunn, J TI Ion implantation of epitaxial GaN films: Damage, doping and activation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID BLUE; DIODES; LAYERS AB Monocrystalline GaN films grown on AIN buffer layers previously deposited on 6H-SiC(0001) wafers and having dislocation densities on the order of 10(7) cm/cm(3) beyond 0.5 mu m from the initial growth interface have been achieved via chemical vapor deposition (CVD), The absence of low angle grain boundaries invariably extant in GaN films deposited on sapphire substrates and the relatively low dislocation densities and absence of stacking faults and twinning in the implantation regions of the films make them the best materials available for the study of implantation doping, In our initial study, 160 keV Si (n-type) and 120 keV Mg (p-type) with projected range similar to 110 nm and fluences of 1e14, 5e14 and 1e15 cm(-2) were implanted at both room temperature and 550 degrees C, The samples were characterized by Rutherford backscattering (RBS)/channeling and photoluminescence (PL) techniques before and after implantation, RBS/channeling results of virgin and as-implanted GaN for 120 keV Mg at 550 degrees C and 1e15 cm(-2) fluence showed that even at this comparatively high dose the implantation damage is very little, However the characteristic PL signal which was present before the implantation disappeared even for the lowest dose (1e14 cm(-2)), These samples were annealed in a rapid thermal annealing furnace at 1000 degrees C, and damage recovery and dopant activation were measured by FL, RBS/channeling and Cross-Sectional TEM (XTEM). C1 N CAROLINA STATE UNIV,DEPT MAT SCI & ENGN,RALEIGH,NC 27695. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP Parikh, N (reprint author), UNIV N CAROLINA,DEPT PHYS & ASTRON,CHAPEL HILL,NC 27599, USA. NR 10 TC 32 Z9 33 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 463 EP 466 DI 10.1016/S0168-583X(97)00076-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500104 ER PT J AU Zolper, JC Crawford, MH Williams, JS Tan, HH Stall, RA AF Zolper, JC Crawford, MH Williams, JS Tan, HH Stall, RA TI High dose Si- and Mg-implantation in CaN: Electrical and structural analysis SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID GAN AB The implantation of Si-donors and Mg-acceptors in GaN was studied for doses from 1 x 10(14) to 1 x 10(16) cm(-2) and annealing at 1100 degrees C. The transport and luminescence properties were compared to Ar-implanted samples at the same doses. For a Si dose of 1 x 10(16) cm(-2) a sheet electron density of 5 x 10(15) cm(-2) was measured after annealing. Since a same dose Ar-implant resulted in only a sheet electron density of 3.3 x 10(13) cm(-2), the flee electron density in the Si-sample is not attributable to implant damage but is the result of electrically active Si-donors. For a Mg dose of 5 x 10(15) cm(-2) the sheet carrier concentration is only 8 x 10(11) cm(-2) which suggests, even when accounting for the ionization energy of Mg in GaN of similar to 170 meV, that no significant Mg-activation has occurred or that it is compensated by the implantation induced damage. Channeling Rutherford backscattering and cross-sectional electron microscopy demonstrates that at high doses (6 x 10(15) cm(-2)) even annealing at 1100 degrees C, as required to activate implanted dopants, does not significantly reduce the implantation induced disorder. Therefore, at least for Si-donors, the complete removal of implant damage is not required to achieve electrically active implanted dopants in GaN. C1 AUSTRALIAN NATL UNIV,DEPT ELECT MAT ENGN,CANBERRA,ACT 0200,AUSTRALIA. EMCORE CORP,SOMERSET,NJ 08873. RP Zolper, JC (reprint author), SANDIA NATL LABS,DEPT 1314,MS0603,ALBUQUERQUE,NM 87185, USA. RI Tan, Hark Hoe/M-1148-2015 OI Tan, Hark Hoe/0000-0002-7816-537X NR 17 TC 12 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 467 EP 470 DI 10.1016/S0168-583X(96)00973-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500105 ER PT J AU Magruder, RH Zuhr, RA Hensley, DK Withrow, S AF Magruder, RH Zuhr, RA Hensley, DK Withrow, S TI Photosensitivity of B, Si and N implanted silica SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID ABSORPTION-BANDS; ION-IMPLANTATION; OXYGEN AB Silica was implanted with B and N ions at 4 MeV and Si ions at 5 MeV with nominal doses of 1 x 10(16) ions/cm(2). The samples were exposed to 245 nm KrF excimer irradiation with a fluence of 150 mJ/cm(2) per pulse for pulse totals of 1.5, 15 and 30 J/cm(2). The optical absorption from 200 to 450 nm was measured before and after each series of KrF irradiations. Broad peaks at 210 and 245 nm are observed in the absorption spectra. The magnitude of the absorption as well as the photosensitive response is dependent on the implanted ion species. We attribute the differences observed in the absorption of the as implanted samples and their response to KrF irradiation to differences in the ion-solid interactions. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP Magruder, RH (reprint author), BELMONT UNIV,DEPT PHYS,NASHVILLE,TN 37212, USA. RI Hensley, Dale/A-6282-2016 OI Hensley, Dale/0000-0001-8763-7765 NR 15 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 492 EP 496 DI 10.1016/S0168-583X(96)00978-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500111 ER PT J AU Williams, EK Ila, D Sarkisov, S Venkateswarlu, P Poker, DB Hensley, DK AF Williams, EK Ila, D Sarkisov, S Venkateswarlu, P Poker, DB Hensley, DK TI Loss measurements and stoichiometric dependence of Ti and O implanted LiNbO3 waveguides SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB Planar waveguides created by the implantation at 500 degrees C of 2.5 x 10(17) Ti ions/cm(2) and 2.5, 5.0 and 7.5 x 10(17) O ions/cm(2) have been characterized for loss by the scattered light and cutback techniques, Results indicate losses of less than 2.5 dB/cm to 3 dB/cm for waveguides with a Ti:O ratio of 1:3 and losses of over 7 dB/cm2 for waveguides with Ti:O ratios of I: 1 and 1:2. C1 ALABAMA A&M UNIV,CTR IRRADIAT MAT,NORMAL,AL 35762. ALABAMA A&M UNIV,CTR NONLINEAR OPT,NORMAL,AL 35762. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Hensley, Dale/A-6282-2016 OI Hensley, Dale/0000-0001-8763-7765 NR 11 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 512 EP 514 DI 10.1016/S0168-583X(96)00981-0 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500115 ER PT J AU Qian, Y Ila, D Zimmerman, RL Poker, DB Boatner, LA Hensley, DK AF Qian, Y Ila, D Zimmerman, RL Poker, DB Boatner, LA Hensley, DK TI MeV silver ion implantation induced changes in optical properties of MgO (100) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID CRYSTALS AB The implantation of 1.5 MeV Ag inns at 1.2 x 10(17) ion/cm(2) into MgO(100) single crystals produces optical absorption color centers which can be reduced by heat treatment at temperatures above 1000 degrees C. We observed the formation of both F-centers and V-centers. We observed optical absorption due to the formation of silver nanoclusters at heat treatment temperatures above 550 degrees C and due to F-center aggregates at heat treatment above 800 degrees C. Upon further heat treatment, the color centers diminish while absorption due to the Ag nanoclusters is enhanced. Using Mie's theory we confirmed that Ag is in the form of nanoclusters and by using Rutherford backscattering spectrometry (RES) and ion channeling, we confirmed that these Ag metallic clusters have, in fact, orientations similar to that of the host substrate, MgO. The measured optical absorption due to Ag nanocrystals, 430 nm, is in agreement with the theoretical prediction. C1 ALABAMA A&M UNIV,DEPT PHYS,CTR IRRADIAT MAT,NORMAL,AL 35762. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Hensley, Dale/A-6282-2016; Boatner, Lynn/I-6428-2013 OI Hensley, Dale/0000-0001-8763-7765; Boatner, Lynn/0000-0002-0235-7594 NR 14 TC 23 Z9 24 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 524 EP 527 DI 10.1016/S0168-583X(96)00984-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500118 ER PT J AU White, CW Budai, JD Withrow, SP Zhu, JG Pennycook, SJ Zuhr, RA Hembree, DM Henderson, DO Magruder, RH Yacaman, MJ Mondragon, G Prawer, S AF White, CW Budai, JD Withrow, SP Zhu, JG Pennycook, SJ Zuhr, RA Hembree, DM Henderson, DO Magruder, RH Yacaman, MJ Mondragon, G Prawer, S TI Encapsulated nanocrystals and quantum dots formed by ion beam synthesis SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID IMPLANTED SILICA GLASS; OPTICAL-PROPERTIES; GE NANOCRYSTALS; SI; LUMINESCENCE; CONFINEMENT; LAYERS AB High-dose ion implantation has been used to synthesize a wide range of nanocrystals and quantum dots and to encapsulate them in host materials such as SiO2, alpha-Al2O3, and crystalline Si. When Si nanocrystals are encapsulated in SiO2, they exhibit dose dependent absorption and photoluminescence which provides insight into the luminescence mechanism, Compound semiconductor nanocrystals (both group III-V and group II-VI) can be formed in these matrices by sequential implantation of the individual constituents, and we discuss their synthesis and some of their physical and optical properties. C1 OAK RIDGE Y-12 PLANT, OAK RIDGE, TN USA. FISK UNIV, NASHVILLE, TN USA. VANDERBILT UNIV, NASHVILLE, TN USA. Univ Nacl Autonoma Mexico, MEXICO CITY, DF, MEXICO. UNIV MELBOURNE, SCH PHYS, PARKVILLE, VIC 3052, AUSTRALIA. RP White, CW (reprint author), OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RI jose yacaman, miguel/B-5622-2009; Budai, John/R-9276-2016; OI Budai, John/0000-0002-7444-1306; PRAWER, STEVEN/0000-0002-4959-0828 NR 33 TC 46 Z9 46 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 545 EP 552 DI 10.1016/S0168-583X(96)00988-3 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500123 ER PT J AU Gea, LA Boatner, LA Evans, HM Zuhr, R AF Gea, LA Boatner, LA Evans, HM Zuhr, R TI Optically active surfaces formed by ion implantation and thermal treatment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID VO2 THIN-FILMS AB Embedded VO2 precipitates have been formed in single-crystal sapphire by the ion co-implantation of vanadium and oxygen and subsequent thermal annealing, The embedded VO2 particles have been shown to exhibit an optical switching behavior that is comparable to that of continuous thin films. In this work, the mechanisms of formation of these optically active particles are investigated, It is shown that precipitation of the vanadium dioxide phase is favored when the thermal treatment is performed on an ion-damaged but still crystalline (rather than amorphized) Al2O3 substrate, The best optical switching behavior is observed in this case, and this behavior is apparently correlated with a more-favorable dispersion of VO2 small particles inside the matrix. RP Gea, LA (reprint author), OAK RIDGE NATL LAB, DIV SOLID STATE, POB 2008, MS-6056, OAK RIDGE, TN 37831 USA. RI Boatner, Lynn/I-6428-2013 OI Boatner, Lynn/0000-0002-0235-7594 NR 9 TC 7 Z9 8 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 553 EP 556 DI 10.1016/S0168-583X(96)00989-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500124 ER PT J AU Ila, D Wu, Z Smith, CC Poker, DB Hensley, DK Klatt, C Kalbitzer, S AF Ila, D Wu, Z Smith, CC Poker, DB Hensley, DK Klatt, C Kalbitzer, S TI Post bombardment enhanced optical absorption in gold implanted silica SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID ION-IMPLANTATION; GLASS AB We have demonstrated that the post bombardment of 3.6 MeV Au implanted suprasil by 1.2 MeV boron, 2.0 MeV boron and 0.9 MeV alpha particles can induce the formation of Au nanoclusters. We have also demonstrated that post bombardment increases the annealing temperatures necessary for Au cluster formation beyond 1000 degrees C. The optical absorption band characteristic of the Au implanted suprasil was used to monitor the formation of the metallic clusters before and after post bombardment as well as st each annealing temperature. C1 NASA,MSFC,REDSTONE ARSENAL,AL 35898. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. MAX PLANCK INST KERNPHYS,D-69029 HEIDELBERG,GERMANY. RP Ila, D (reprint author), ALABAMA A&M UNIV,DEPT PHYS,CTR IRRADIAT MAT,POB 1447,NORMAL,AL 35762, USA. RI Hensley, Dale/A-6282-2016 OI Hensley, Dale/0000-0001-8763-7765 NR 10 TC 26 Z9 26 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 570 EP 573 DI 10.1016/S0168-583X(96)01127-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500128 ER PT J AU Venturini, EL Newcomer, PP Schone, H Doyle, BL Myers, KE AF Venturini, EL Newcomer, PP Schone, H Doyle, BL Myers, KE TI Strongly enhanced vortex pinning in high-energy, heavy-ion-irradiated, superconducting Tl-Ba-Ca-Cu-O films SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID SINGLE-CRYSTAL; CRITICAL CURRENTS; RESISTIVITY; IRREVERSIBILITY; MAGNETIZATION; YBA2CU3O7; DEFECTS; DAMAGE; MODEL AB Lattice damage introduced in high-temperature superconducting Tl2Ba2CaCu2Oy thin films by irradiation with 60 MeV Cu9+ ions produces a large enhancement in both the critical current density J(cm) and the vortex volume pinning force. These promising effects are observed for a fluence of 2 x 10(11) ions/cm(2) that causes a small decrease (similar to 4%) in the superconducting transition temperature. At 40 K in a one Tesla magnetic field applied along the crystallographic c-axis, at dissipation levels dictated by the SQUID magnetometer, J(cm) is increased by orders of magnitude following irradiation. High-resolution transmission electron microscopy reveals extended, linear defects following irradiation that provide strong vortex pinning sites, allowing much higher J(cm). C1 DUPONT CO INC,SUPERCONDUCT,WILMINGTON,DE 19880. RP Venturini, EL (reprint author), SANDIA NATL LABS,MAIL STOP 1421,ALBUQUERQUE,NM 87185, USA. NR 19 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 587 EP 590 DI 10.1016/S0168-583X(96)01136-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500133 ER PT J AU Yu, N Nastasi, M Sickafus, KE Yasuda, K Tesmer, JR AF Yu, N Nastasi, M Sickafus, KE Yasuda, K Tesmer, JR TI In situ study of ion-beam induced lattice damage in calcium fluoride crystals SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID SINGLE-CRYSTALS; UO2; IMPLANTATION AB Lattice damage in calcium fluoride induced by 360 keV xenon ion irradiation was measured in situ using Rutherford backscattering and channeling (RBS/C) techniques. Calcium fluoride single crystals of (100) orientation were irradiated at -115 and 35 degrees C by Xe ion beams along a random direction 15 degrees off the (100) axis. A 2 MeV He ion-beam from a 3 MV tandem accelerator was incident on the CaF2 crystal along the (110) axis to determine the radiation damage. No amorphized layer was observed at both irradiation temperatures up to an irradiation dose of 2 x 10(16) Xe/cm(2). RBS/C measurements showed that lattice disorder in the irradiated layer saturated at 70% of the random level. Analysis of cross-sectional transmission electron microscopy (XTEM) revealed a damaged but single-crystalline CaF2 layer. This study demonstrates the radiation tolerance of CaF2 under displacive irradiation at low to ambient temperatures. C1 TEXAS INSTRUMENTS INC,SEMICOND PROC & DEVICE CTR,DALLAS,TX 75243. KYUSHU UNIV,DEPT NUCL ENGN,FUKUOKA 81281,JAPAN. RP Yu, N (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 14 TC 11 Z9 11 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 591 EP 595 DI 10.1016/S0168-583X(96)01138-X PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500134 ER PT J AU McHargue, CJ Hunn, JD Joslin, DL Alves, E daSilva, MF Soares, JC AF McHargue, CJ Hunn, JD Joslin, DL Alves, E daSilva, MF Soares, JC TI Etching of amorphous Al2O3 produced by ion implantation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB Single crystal Al2O3 (sapphire) is noted for its extreme resistance to attack by most chemical reagents. The reactivity of amorphous Al2O3 has not been reported although it is well known that an amorphous layer can be produced by ion beam irradiation at 77 K or by implantation of certain chemical species at 300 K, In the current study, an amorphous layer was produced by ion beam mixing of Zr/Al2O3 using Kr at 300 K; or by implantation with Cr, Zr, Sn or Al plus 0 at 77 K. The amorphous layer can be completely removed by etching in an acid solution of HNO3-HF-H2O. The attack ceases once the amorphous region is dissolved. Crystalline samples containing the same implanted species are not attacked. The amorphous state is necessary for this enhanced chemical reactivity and the results for the stoichiometric implant of Al + O indicate that it is sufficient. The implanted (impurity) species may influence the rate of dissolution. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NUCL & TECHNOL INST,SACAVEM,PORTUGAL. RP McHargue, CJ (reprint author), UNIV TENNESSEE,CTR MAT PROC,100 ESTABROOK HALL,KNOXVILLE,TN 37996, USA. RI Alves, Eduardo/K-2481-2013; OI Alves, Eduardo/0000-0003-0633-8937; Soares, Jose/0000-0001-5277-4575 NR 10 TC 17 Z9 17 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 596 EP 598 DI 10.1016/S0168-583X(96)01139-1 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500135 ER PT J AU Devanathan, R Yu, N Sickafus, KE Nastasi, M AF Devanathan, R Yu, N Sickafus, KE Nastasi, M TI Structure and property changes in spinel irradiated with heavy ions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID CERAMIC INSULATORS AB We have studied the changes in microstructure and elastic modulus of single crystal MgAl2O4 irradiated with 12 MeV Au3+ at about 100 K to a fluence of 1.5 x 10(16) ions/cm(2). High-resolution electron microscopy and electron diffraction from cross-sectional samples indicate that the irradiated layer remains crystalline even after a peak damage dose of about 33 displacements per atom (dpa). In addition, dark-field electron microscopy reveals that the irradiated layer contains small defect clusters which indicate a high point defect mobility. Young's modulus determined by nano-indentation does not show any significant changes. These results, which are in contrast to the amorphization and 30% decrease in Young's modulus previously observed following 400 keV Xe2+ irradiation at 100 K, are interpreted in terms of the large electronic to nuclear stopping power ratio of the 12 MeV Au3+ irradiation and the possibility of beam heating during irradiation. C1 LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. TEXAS INSTRUMENTS INC,SEMICOND PROC & DEVICE CTR,DALLAS,TX 75243. RI Devanathan, Ram/C-7247-2008 OI Devanathan, Ram/0000-0001-8125-4237 NR 9 TC 13 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 608 EP 611 DI 10.1016/S0168-583X(96)01130-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500138 ER PT J AU Mitchell, JN Yu, N Devanathan, R Sickafus, KE Nastasi, MA Nord, GL AF Mitchell, JN Yu, N Devanathan, R Sickafus, KE Nastasi, MA Nord, GL TI Ion irradiation damage in ilmenite at 100 K SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID ALUMINATE SPINEL; CATION DISORDER; AMORPHIZATION; CRYSTAL AB A natural single crystal of ilmenite (FeTiO3) was irradiated at 100 K with 200 keV Ar2+. Rutherford backscattering spectroscopy and ion channeling with 2 MeV He+ ions were used to monitor damage accumulation in the surface region of the implanted crystal, At an irradiation fluence of 1 x 10(15) Ar2+/cm(2), considerable near-surface He+ ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO3) and spinel (MgAl2O4) to explore factors that may influence radiation damage response in oxides. C1 US GEOL SURVEY,RESTON,VA 22092. RP Mitchell, JN (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. RI Devanathan, Ram/C-7247-2008 OI Devanathan, Ram/0000-0001-8125-4237 NR 26 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 629 EP 633 DI 10.1016/S0168-583X(96)01140-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500143 ER PT J AU Lu, YC Kung, H Jervis, TR Hirvonen, JP Ruck, D Mitchell, TE Nastasi, M AF Lu, YC Kung, H Jervis, TR Hirvonen, JP Ruck, D Mitchell, TE Nastasi, M TI Effect of 690-keV Xe ion irradiation on the microstructure of amorphous MoSi2/SiC nanolayer composites SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB The effect of 690-keV Xe ion irradiation at three different dosage levels, 1 x 10(15), 5 x 10(15) and 10 x 10(15)/cm(2), on the microstructure of amorphous-MoSi2/amorphous-SiC nanolayer composites has been studied using transmission electron microscopy. Results show that the depth of radiation damage in this multilayer material is similar to 80 nm, which agrees qualitatively well with the calculated damage depth calculated by TRIM [1]. A diffraction ring corresponding to the (10 (1) over bar 1) plane of C40 MoSi2 was found in the electron diffraction pattern taken from the irradiated regions; the C30 phase is also found after thermal annealing of amorphous MoSi2 at 500 degrees C or above. In the damaged regions SiC layers were found to spheroidize while the nanocrystalline grains in the MoSi2 layers appeared to coarsen with increasing dose. C1 JOINT RES CTR,NL-1755 ZG PETTEN,NETHERLANDS. LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. GSI DARMSTADT,D-64291 DARMSTADT,GERMANY. NR 6 TC 1 Z9 1 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 648 EP 650 DI 10.1016/S0168-583X(96)01145-7 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500147 ER PT J AU Rao, MV Nordstrom, D Gardner, JA Edwards, A Roth, EG Kelner, G Ridgway, M AF Rao, MV Nordstrom, D Gardner, JA Edwards, A Roth, EG Kelner, G Ridgway, M TI Ion implantation in 6H-SiC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB In this study we have performed N, P, Al, B, V, Si, and C implantations to obtain p-type, n-type, and semi-insulating regions in 6H-SiC crystals. Post-implantation annealings were performed in either a conventional ceramic processing furnace or using microwaves in the temperature range of 1200-1700 degrees C, The material was characterized by secondary ion mass spectrometry, Hall, Rutherford backscattering via channeling, and two-probe I-V measurements. N-type regions with a maximum room temperature electron concentration of 2 x 10(19) cm(-3) were obtained using N and P implantations, Though p-type regions were obtained by Al and B, the room temperature hole concentrations were low due to the deep acceptor levels associated with these impurities. The Si and C bombardment gave regions with resistivities as high as 10(9) Omega cm compared to 1 Omega cm in the starting material. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. USN,RES LAB,WASHINGTON,DC 20375. AUSTRALIAN NATL UNIV,DEPT ELECT MAT ENGN,CANBERRA,ACT,AUSTRALIA. RP Rao, MV (reprint author), GEORGE MASON UNIV,DEPT ELECT & COMP ENGN,FAIRFAX,VA 22030, USA. RI Ridgway, Mark/D-9626-2011 OI Ridgway, Mark/0000-0002-0642-0108 NR 16 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 655 EP 659 DI 10.1016/S0168-583X(96)01147-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500149 ER PT J AU Evelyn, AL Ila, D Zimmerman, RL Bhat, K Poker, DB Hensley, DK AF Evelyn, AL Ila, D Zimmerman, RL Bhat, K Poker, DB Hensley, DK TI Resolving the electronic and nuclear effects of MeV ions in polymers SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID PHENOLFORMALDEHYDE; RESIN; FILMS AB The electronic and nuclear stopping effects produced by MeV ion bombardment in polyvinylidene chloride (PVDC) and polyethylene (PE) were separated by stacking thin films of the polymers. The resulting layered system consisting of each polymer was bombarded with 3.5 and 5.0 MeV alpha particles, A layered system was selected such that the first layers experienced most of the effects of the electronic energy deposited and the last layers received most of the effects of the nuclear stopping. The electrical conductance and the changes in the chemical structure were measured by direct resistivity measurements, Raman microprobe analysis and FTIR. Post-irradiation analyses of the films indicated differences in these properties in the various film layers which are attributed to the individual effects of the stopping powers in the polymer films. C1 ALABAMA A&M UNIV,DEPT PHYS,CTR IRRADIAT MAT,NORMAL,AL 35762. ALABAMA A&M UNIV,DEPT CHEM,NORMAL,AL 35762. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Hensley, Dale/A-6282-2016 OI Hensley, Dale/0000-0001-8763-7765 NR 19 TC 42 Z9 42 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 694 EP 697 DI 10.1016/S0168-583X(97)80046-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500158 ER PT J AU Johnson, E Touboltsev, VS Johansen, A Dahmen, U Hagege, S AF Johnson, E Touboltsev, VS Johansen, A Dahmen, U Hagege, S TI TEM and RBS/channelling of nanosized bicrystalline (Pb,Cd) inclusions in Al made by sequential ion implantation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID HETEROGENEOUS NUCLEATION; THALLIUM INCLUSIONS; ALUMINUM; SOLIDIFICATION; MATRIX; EVOLUTION AB Sequential ion implantation of Pb and Cd in Al at 425 K and 475 K respectively has been used to produce dense distributions of nanosized (Pb,Cd) inclusions with equiatomic composition. Pb and Cd form a simple eutectic system, but both elements are insoluble in solid Al, and the inclusions are Cd-rich in comparison with the eutectic composition. Inclusions in the size range from 1 to 20 nm were observed in as-implanted samples. Their overall shape was nearly cuboctahedral. Most of the inclusions were bicrystalline with an fee Pb part forming a segment of a cuboctahedron and an hcp Cd slab attached to one of the {111}(Pb) facets. The orientation relationship had close-packed planes and directions parallel in the three structures, In situ melting/solidification experiments combining TEM and RBS/channelling showed that melting of the inclusion ensemble occurs within a narrow temperature interval of 10-15 K around the eutectic temperature of 521 K. Solidification takes place with undercoolings of about 50-65 K below the liquidus line in a two-stage process where Cd solidifies 15 to 20 K before Pb. C1 NIELS BOHR INST,ORSTED LAB,DK-2100 COPENHAGEN O,DENMARK. CECM,CNRS,F-94407 VITRY SUR SEINE,FRANCE. RP Johnson, E (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720, USA. NR 25 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 727 EP 733 DI 10.1016/S0168-583X(96)01166-4 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500165 ER PT J AU Oks, EM Anders, A Brown, IG Dickinson, MR MacGill, RA AF Oks, EM Anders, A Brown, IG Dickinson, MR MacGill, RA TI High energy implantation with high-charge-state ions in a vacuum arc ion implanter SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID MAGNETIC-FIELD; BEAM AB Ion implantation energy can in principle be increased by increasing the charge states of the ions produced by the ion source rather than by increasing the implanter operating voltage, providing an important savings in cost and size of the implanter. In some recent work we have shown that the charge states of metal ions produced in a vacuum are ion source can be elevated by a strong magnetic field. In general, the effect of both high are current and high magnetic field is to push the distribution to higher charge states - the mean ion charge state is increased and new high charge states are formed. The effect is significant for implantation application - the mean ion energy can be about doubled without change in extraction voltage. Here we describe the ion source modifications, the results of time-of-flight (TOF) measurements of ion charge state distributions, and discuss the use and implications of this technique as a means for doing metal ion implantation in the multi-hundreds of keV ion energy range. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RUSSIAN ACAD SCI,INST HIGH CURRENT ELECT,TOMSK 634050,RUSSIA. STATE ACAD CONTROL SYST & RADIOELECT,TOMSK 634050,RUSSIA. RI Oks, Efim/A-9409-2014; Anders, Andre/B-8580-2009 OI Oks, Efim/0000-0002-9323-0686; Anders, Andre/0000-0002-5313-6505 NR 20 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 779 EP 781 DI 10.1016/S0168-583X(97)00006-2 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500176 ER PT J AU Oks, EM Yushkov, GY Evans, PJ Oztarhan, A Brown, IG Dickinson, MR Liu, F MacGill, RA Monteiro, OR Wang, Z AF Oks, EM Yushkov, GY Evans, PJ Oztarhan, A Brown, IG Dickinson, MR Liu, F MacGill, RA Monteiro, OR Wang, Z TI Hybrid gas-metal co-implantation with a modified vacuum arc ion source SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID BEAM AB Energetic beams of mixed metal and gaseous ion species can be generated with a vacuum arc ion source by the addition of gas to the are discharge region under appropriate conditions. This operational mode could prove to be an important tool for ion implantation research by providing a method for forming buried layers of mixed composition such as, for example, metal oxides and nitrides. In work to-date, we have formed a number of mixed metal-gas ion beams including Ti + N, Pt + N, Al + O and Zr + O. The particle current fractions of the metal-gas ion components in the beam ranged from 100% metallic to approximately 80% gaseous depending on the operational parameters, We have used this new variant of the vacuum are ion source to carry out some exploratory investigations of the effect of Al + O and Zr + O co-implantation on the tribological characteristics of stainless steel. Here we describe the ion source modifications, the species and charge state composition of the hybrid beams produced, and the results of some preliminary investigations of the surface modification of stainless steel by co-implantation of mixed aluminum/oxygen or zirconium/oxygen ion beams. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RUSSIAN ACAD SCI,INST HIGH CURRENT ELECT,TOMSK 634050,RUSSIA. STATE ACAD CONTROL SYST & RADIOELECT,TOMSK 634050,RUSSIA. AUSTRALIAN NUCL SCI & TECHNOL ORG,SUTHERLAND,NSW 2234,AUSTRALIA. DOKUZ EYLUL UNIV,TR-35100 IZMIR,TURKEY. RI Oks, Efim/A-9409-2014; Yushkov, Georgy/O-8024-2015 OI Oks, Efim/0000-0002-9323-0686; Yushkov, Georgy/0000-0002-7615-6058 NR 24 TC 21 Z9 25 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 782 EP 786 DI 10.1016/S0168-583X(97)00007-4 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500177 ER PT J AU Monteiro, OR Wang, Z Hou, PY Brown, IG AF Monteiro, OR Wang, Z Hou, PY Brown, IG TI Synthesis of multi-element thin-films using mixed metal plasma streams SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID VACUUM-ARC PLASMAS; ION-IMPLANTATION; SURFACE MODIFICATION; MULLITE; DEPOSITION; FILTERS AB Multi-element thin films of complex structure have been formed by an ion-energy-controlled, plasma-based method. Metal plasmas produced by two independent, filtered, vacuum are guns are directed toward the substrate and mixed together in a magnetic multipole plasma homogenizer. Ion energy is controlled by repetitively pulse-biasing the substrate, providing a means to enhance adhesion between the substrate and the growing film (by ion mixing at the interface) as well as to modify the film microstructure (by ion assisted deposition). Here we outline the plasma/ion beam technique and present some examples of films produced, including silicon-aluminum oxides, and films of refractory metal carbides. For Al:Si oxides, two plasma sources were used in an oxygen background and the Al:Si ratio in the films was controlled by varying the relative are duration; films with Al:Si ratios varying from 2:1 to 8:1 were produced. For the case of carbide films, Ti and C plasma streams were mixed so as to form films of TixCy. As well as monolithic films, we have also used this plasma technique to form multilayer structures of TiC:DLC. The method provides a relatively simple and convenient approach to the plasma synthesis of complex multi-element thin films and multilayer structures. RP Monteiro, OR (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BLDG 53,BERKELEY,CA 94720, USA. NR 28 TC 21 Z9 21 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 821 EP 826 DI 10.1016/S0168-583X(97)00014-1 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500184 ER PT J AU Ji, H Was, GS Jones, JW Moody, NR AF Ji, H Was, GS Jones, JW Moody, NR TI Microstructure and mechanical properties of IBAD niobium films on sapphire substrates SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID DEPOSITION AB The effect of ion bombardment during film deposition on the microstructure, surface morphology, residual stress, hardness and interfacial fracture energy was determined for Nb films on sapphire substrates, In the present study, niobium films of nominal thickness 100 nm were deposited on (0001) sapphire substrates by Physical Vapor Deposition (PVD) and by Ion Beam Assisted Deposition (IBAD) at an ion energy E = 1000 eV and an ion-to-atom arrival rate ratio R = 0.4. The microstructures of the PVD and IBAD films were very similar, but the IBAD film had a much rougher surface. Ion bombardment also changed the residual stress state from tensile (224 MPa) for the PVD film to compressive (-400 MPa) for the IBAD film, The IBAD film had a lower hardness (5.7 GPa) than the PVD film (10.9 GPa) as determined by nanoindentation. An attempt was made to measure the fracture energy of both the PVD niobium-sapphire and IBAD niobium-sapphire interfaces by scratch test and nanoindentation. The PVD sample failed in a brittle manner in both tests and interfacial fracture energies were able to be estimated. By contrast, the IBAD sample failed in a ductile manner in both tests, precluding the determination of the interfacial fracture energy. C1 UNIV MICHIGAN,DEPT NUCL ENGN & RADIOL SCI,ANN ARBOR,MI 48109. UNIV MICHIGAN,DEPT MAT SCI & ENGN,ANN ARBOR,MI 48109. SANDIA NATL LABS,LIVERMORE,CA 94551. RP Ji, H (reprint author), UNIV MICHIGAN,DEPT PHYS,120 NA & ME BLDG,2600 DRAPER RD,ANN ARBOR,MI 48109, USA. NR 12 TC 1 Z9 1 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 846 EP 850 DI 10.1016/S0168-583X(97)00019-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500189 ER PT J AU Funsten, HO Shappirio, M AF Funsten, HO Shappirio, M TI Sputtering of thin carbon foils by 20 keV and 40 keV Ar+ bombardment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID SCATTERING; IONS AB Sputtering of nominal 2 mu g/cm(2) carbon foils by 20 keV and 40 keV Ar+ bombardment has been measured using thickness measurements derived from the angular scatter distribution of 2 keV protons transiting the foils. The total sputtering yield is observed to reach a constant rate of 3.5 atoms removed per incident Ar+ and is independent of both the foil thickness and the incident energy. This is attributed to a nearly constant deposited energy density at the entrance and exit surfaces, which results from a nuclear stopping power that varies little over the energy range of 6-40 keV. By extrapolating measured backsputtering yield data to the energies used in this study, we obtain a transmission sputtering yield of approximately 1.7. Holes were also formed in the foil, and the fraction of holes created by Ar+ bombardment linearly increases with increasing fluence above a threshold fluence of 4.5 x 10(15) Ar+/cm(2). RP Funsten, HO (reprint author), LOS ALAMOS NATL LAB,MS D466,LOS ALAMOS,NM 87545, USA. RI Funsten, Herbert/A-5702-2015 OI Funsten, Herbert/0000-0002-6817-1039 NR 28 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 905 EP 909 DI 10.1016/S0168-583X(97)00079-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500202 ER PT J AU Knapp, JA Follstaedt, DM Barbour, JC Myers, SM AF Knapp, JA Follstaedt, DM Barbour, JC Myers, SM TI Finite-element modeling of nanoindentation for determining the mechanical properties of implanted layers and thin films SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID HARDNESS; ALUMINUM AB The mechanical properties of implanted layers and thin films on dissimilar substrates are difficult to determine accurately. Nanoindentation of the layer provides information, but detailed numerical modeling is required in order to separate the properties of the layer from those of the substrate. We describe here the procedures we have developed to accomplish this modeling with the commercially available finite-element code ABAQUS. Using these techniques, we are able to extract from nanoindentation testing the yield stress, Young's modulus, and hardness of the layer material, with an absolute accuracy of at least 20%. The procedure is applicable to layers as thin as 50 nm on essentially any substrate, hard or soft. We have used it for materials ranging from ion-implanted layers to thin films of metals and dielectrics formed using plasma-deposition methods. An example is given of O-implanted Al, a thin, hard layer on a soft substrate. RP Knapp, JA (reprint author), SANDIA NATL LABS,MS 1056,ALBUQUERQUE,NM 87185, USA. NR 13 TC 20 Z9 21 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 935 EP 939 DI 10.1016/S0168-583X(97)00034-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500207 ER PT J AU Kern, KT Walter, KC Griffin, AJ Lu, Y Nastasi, M Scarborough, WK Tesmer, JR Fayeulle, S AF Kern, KT Walter, KC Griffin, AJ Lu, Y Nastasi, M Scarborough, WK Tesmer, JR Fayeulle, S TI Boron and nitrogen implantation of steels SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID WEAR-RESISTANCE AB Samples of four steels with varying chromium content were implanted with boron and seperately with nitrogen. Implantation energy was 75 keV in all cases. Implantation profiles were modeled using TRIM and determined experimentally by ion beam analysis. Boron ion sources leading to improved ion beams will be discussed, Material characterization included tribology and nano-indentation, Implanted materials showed improvements in wear resistance in all cases involving boron implantation, while nitrogen implantation resulted in improved wear resistance for three of the four materials. Reduced coefficients of friction were observed for boron implanted materials with a surface layer of amorphous carbon. The improvement of wear rate due to implantation and reduced coefficient of friction due to the carbon layer were independent results allowing for separate control of these properties. Nano-indentation results show an increase in the hardness of the implanted regions for two of the materials, 1018 and 304. Results of micro-structural analysis through grazing incidenceglancing angle X-ray diffraction showed iron-nitride formation and in one case chromium-nitride formation, Evidence of iron-boride compound formation in boron implanted materials has been seen. C1 LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. ECOLE CENT LYON,LAB MMP,URA CNRS 447,ECULLY,FRANCE. RP Kern, KT (reprint author), NORFOLK STATE UNIV,CTR MAT RES,2401 CORPREW AVE,NORFOLK,VA 23504, USA. NR 7 TC 6 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 972 EP 976 DI 10.1016/S0168-583X(97)00041-4 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500214 ER PT J AU Williams, JM Miner, JR AF Williams, JM Miner, JR TI Ion implantation of silicon nitride ball bearings SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB A program has existed for determination of the effect of ion implantation on the rolling contact performance of silicon nitride ball bearings. The hypothesis was that stress concentrations reflected into the bulk due to topography such as polishing imperfections, texture in the race, or transferred material, might be reduced due to surface amorphization. Forty-two control samples were tested to an intended runout period of 60 h. Six ion implanted balls were tested to an extended period of 150 h. The bearing test equipment provided for accelerated testing, in a V-groove arrangement, so that wear was on two narrow wear tracks. Other techniques have included Rutherford backscattering, X-ray photoelectron spectroscopy, profilometry, optical microscopy, nanoindentation hardness, and white light interferometry. The balls were implanted with C-ions at 150 keV to a fluence of 1.1 x 10(17)/cm(2). The collection of samples had unanticipated, preexisting, defects called ''C-cracks'' in the surfaces. As a result, failure rate of the control group was unacceptable. None of the ion-implanted samples experienced failure in 150 h of testing. The probability of randomly selecting six samples from the control group that would perform this well is about 5%. Therefore, there is good probability that ion implantation improved performance. Possible reasons are discussed. Analytical techniques have been used to characterize ion implantation results, to characterize wear tracks, and to characterize microstructure and impurity content in possible relation to C-cracks. C1 UNITED TECHNOL CORP,PRATT & WHITNEY,W PALM BEACH,FL 33410. RP Williams, JM (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 12 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 981 EP 986 DI 10.1016/S0168-583X(97)00043-8 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500216 ER PT J AU Rej, DJ Davis, HA Nastasi, M Olson, JC Peterson, EJ Reiswig, RD Walter, KC Stinnett, RW Remnev, GE Struts, VK AF Rej, DJ Davis, HA Nastasi, M Olson, JC Peterson, EJ Reiswig, RD Walter, KC Stinnett, RW Remnev, GE Struts, VK TI Surface modification of AISI-4620 steel with intense pulsed ion beams SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM AB A 300 keV, 30 kA, 1 mu s intense beam of carbon, oxygen, and hydrogen ions is used for the surface treatment of AISI-4620 steel coupons, a common material used in automotive gear applications. The beam is extracted from a magnetically-insulated vacuum diode and deposited into the top 1 mu m of the target surface. The beam-solid interaction causes a rapid melt and resolidification with heating and cooling rates of up to 10(10) K/s. Treated surfaces are smoothed over 1 mu m-scale lengths, but are accompanied by 1 mu m-diameter craters and larger-scale roughening over greater than or equal to 10 mu m, depending on beam fluence and number of pulses. Treated surfaces are up to 1.8 x harder with no discernible change in modulus over depths of 1 mu m or more. Qualitative improvements in the wear morphology of treated surfaces are reported. C1 QM TECHNOL INC,ALBUQUERQUE,NM 87109. INST NUCL PHYS,TOMSK 634050,RUSSIA. RP Rej, DJ (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 7 TC 44 Z9 51 U1 2 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 987 EP 991 DI 10.1016/S0168-583X(97)00044-X PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500217 ER PT J AU Anders, A Brown, IG Dickinson, MR MacGill, RA AF Anders, A Brown, IG Dickinson, MR MacGill, RA TI High energy metal ion implantation using a novel, broad-beam, Marx-generator-based ion source ''Magis'' SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID CHARGE-STATE DISTRIBUTION; MAGNETIC-FIELD; VACUUM-SPARK; PLASMA AB Ion energy of the beam formed by an ion source is proportional to extractor voltage and ion charge state. Increasing the voltage is difficult and costly for extraction voltage over 100 kV. Here we explore the possibility of increasing the charge states of metal ions to facilitate high-energy, broad beam ion implantation at a moderate voltage level. Strategies to enhance the ion charge state include operating in the regimes of high-current vacuum sparks and short pulses. Using a time-of-flight (TOF) technique we have measured charge states as high as 7 + (73 kA vacuum spark discharge) and 4 + (14 kA short pulse are discharge), both for copper, with the mean ion charge states about 6.0 and 2.5, respectively. Pulsed discharges can conveniently be driven by a modified Marx generator, allowing operation of ''Magis'' with a single power supply (at ground potential) for both plasma production and ion extraction. RP UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, MAILSTOP 53, BERKELEY, CA 94720 USA. RI Anders, Andre/B-8580-2009 OI Anders, Andre/0000-0002-5313-6505 NR 16 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X EI 1872-9584 J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 992 EP 995 DI 10.1016/S0168-583X(97)00045-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500218 ER PT J AU Zimmerman, RL Ila, D Poker, DB Withrow, SP AF Zimmerman, RL Ila, D Poker, DB Withrow, SP TI Permeability control of GPC drug delivery system SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Ion Beam Modification of Materials (IBMM-96) CY SEP 01-06, 1996 CL ALBUQUERQUE, NM ID GLASSY-CARBON AB Glassy Polymeric Carbon (GPC), a biocompatible material, has been proposed for drug encapsulation and delivery. We have shown that a wide range of available porosity in the bulk material can be obtained by careful attention to the method of production and heat treatment of GPC. In addition, ion bombardment is shown to modify the available surface porosity and permeability. These surface characteristics are determined by choice of specie, fluence and energy of the bombarding ions, Together with appropriate drug concentration gradients within the capsule, the capsule can be made to deliver an initial dose rate either higher or lower than the steady state value. The effective surface area, as well as the availability of the pores, can be modified by oxygen or gold ion bombardment either to increase or decrease. C1 ALABAMA A&M UNIV,CTR IRRADIAT MAT,NORMAL,AL 35762. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. NR 12 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 1997 VL 127 BP 1023 EP 1026 DI 10.1016/S0168-583X(97)00056-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XG605 UT WOS:A1997XG60500225 ER PT J AU Panvini, RS AF Panvini, RS TI Neutral current couplings of leptons to polarized Z(0)'s in the SLD experiment SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT 4th International Workshop on Tau Lepton Physics CY SEP 16-19, 1996 CL ESTES PK, CO SP US DOE, Natl Sci Fdn, Lecroy Corp, Univ Colorado, Colorado State Univ AB We study neutral current couplings of leptons to polarized Z(0)'s in the SLD experiment in terms of the leptonic asymmetry parameters A(epsilon), A(mu) and A(tau). We discuss in detail e(L,R)(-) + e(+) --> Z(0) + mu(-)mu(+) and tau(-)tau(+), with left(L)- or right(R)-handed polarized electron beams. SLD's most precise measurement of A(epsilon) is shown to result from the left-right cross section asymmetry, A(LR), where the dependence on initial state electronic couplings enable use of essentially all of the data. Comparing A(mu) and A(tau) with A(epsilon) tests the universality of leptonic couplings. A(mu) = 0.102 +/- 0.033 +/- 0.001, A(tau) = 0.190 +/- 0.034 +/- 0.001, and A(epsilon) = 0.148 +/- 0.016 +/- 0.002 from these two leptonic channels. If lepton universality is assumed, a combined asymmetry parameter A(epsilon mu tau) = 0.147 +/- 0.013 results, which directly corresponds to an effective value of the weak mixing angle sin(2) theta(W)(eff) = 0.2315 +/- 0.0017. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP Panvini, RS (reprint author), VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY PY 1997 SU 55C BP 41 EP 48 DI 10.1016/S0920-5632(97)00198-9 PG 8 WC Physics, Particles & Fields SC Physics GA XH377 UT WOS:A1997XH37700005 ER PT J AU Tsai, YS AF Tsai, YS TI Search for new mechanism of CP violation through tau decay and semileptonic decay of hadrons SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT 4th International Workshop on Tau Lepton Physics CY SEP 16-19, 1996 CL ESTES PK, CO SP US DOE, Natl Sci Fdn, Lecroy Corp, Univ Colorado, Colorado State Univ ID K-MU-3 DECAYS; MODEL; NONCONSERVATION; POLARIZATION AB If CP is violated in any decay process involving leptons it will signify the existence of a new force (called the X boson) responsible for CP violation that may be the key to understanding matter-antimatter asymmetry in the universe. We discuss the signatures of CP violation in (I) the decay of tau lepton, and (2) the semileptonic decay of pi, K, D, B and t particles by measuring the polarization of the charged lepton in the decay. We discuss how the coupling constants and their phases of the coupling of the X boson to 9 quark vertices and 3 lepton vertices can be obtained through 12 decay processes. RP Tsai, YS (reprint author), STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94303, USA. NR 21 TC 7 Z9 7 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 MAY PY 1997 SU 55C BP 293 EP 304 PG 12 WC Physics, Particles & Fields SC Physics GA XH377 UT WOS:A1997XH37700033 ER PT J AU Lewis, EE Palmiotti, G AF Lewis, EE Palmiotti, G TI Simplified spherical harmonics in the variational nodal method SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID TRANSPORT METHODS AB The multigroup simplified spherical harmonics equations with anisotropic scattering are derived from a variational principle that preserves nodal balance. The resulting equations are discretized using a Ritz procedure with spatial trial functions that are complete polynomials within the nodes and on the interfaces. The resulting equations are cast in a response matrix form and incorporated as an option of the variational nodal spherical harmonics code VARIANT. Fixed source and multigroup eigenvalue calculations are performed on benchmark problems. The accuracy and computational efficiency of spherical harmonic and simplified spherical harmonic approximations are compared, and the compensating effects of spatial and angular truncation errors are examined. The results indicate that in most situations, simplified and standard spherical harmonics results of the same order are in close agreement, while the use of simplified spherical harmonics substantially reduces computing costs. C1 ARGONNE NATL LAB,RACTOR ANAL DIV,ARGONNE,IL 60439. RP Lewis, EE (reprint author), NORTHWESTERN UNIV,DEPT MECH ENGN,EVANSTON,IL 60208, USA. RI Lewis, Elmer/B-7597-2009 NR 24 TC 17 Z9 17 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD MAY PY 1997 VL 126 IS 1 BP 48 EP 58 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA WU928 UT WOS:A1997WU92800004 ER PT J AU Tsoupas, N Zucker, MS Ward, TE Snead, CL AF Tsoupas, N Zucker, MS Ward, TE Snead, CL TI Uniform particle beam distributions produced by octupole focusing SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID TRANSMUTATION AB The transverse intensity distribution of a beam emerging from a linear accelerator can be described well by a two-dimensional Gaussian function with elliptical contours. A method is presented that utilizes third-order optics to modify this Gaussian beam distribution and to produce at a given location along the beam direction a more uniform beam, which also is confined within a prescribed rectangular area. RP Tsoupas, N (reprint author), BROOKHAVEN NATL LAB,DEPT ADV TECHNOL,POB 5000,UPTON,NY 11793, USA. NR 9 TC 6 Z9 6 U1 1 U2 4 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD MAY PY 1997 VL 126 IS 1 BP 71 EP 79 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA WU928 UT WOS:A1997WU92800006 ER PT J AU Bai, ZJ Demmel, J Gu, M AF Bai, ZJ Demmel, J Gu, M TI An inverse free parallel spectral divide and conquer algorithm for nonsymmetric eigenproblems SO NUMERISCHE MATHEMATIK LA English DT Article ID ALGEBRAIC RICCATI-EQUATIONS; MATRIX-SIGN-FUNCTION; INVARIANT SUBSPACES; SCHUR DECOMPOSITION; LINEAR ALGEBRA; EIGENVALUES; JACOBI AB We discuss an inverse-free, highly parallel, spectral divide and conquer algorithm. It can compute either an invariant subspace of a nonsymmetric matrix A, or a pair of left and right deflating subspaces of a regular matrix pencil A - lambda B. This algorithm is based on earlier ones of Bulgakov, Godunov and Malyshev, but improves on them in several ways. This algorithm only uses easily parallelizable linear algebra building blocks: matrix multiplication and QR decomposition, but not matrix inversion. Similar parallel algorithms for the nonsymmetric eigenproblem use the matrix sign function, which requires matrix inversion and is faster but can be less stable than the new algorithm. C1 UNIV CALIF BERKELEY,DIV COMP SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MATH,BERKELEY,CA 94720. UNIV KENTUCKY,DEPT MATH,LEXINGTON,KY 40506. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RI Gu, Min/B-6627-2008 NR 53 TC 55 Z9 55 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0029-599X J9 NUMER MATH JI Numer. Math. PD MAY PY 1997 VL 76 IS 3 BP 279 EP 308 DI 10.1007/s002110050264 PG 30 WC Mathematics, Applied SC Mathematics GA XB968 UT WOS:A1997XB96800001 ER PT J AU Dattoli, G Voykov, GK Lumpkin, AH Yang, BX AF Dattoli, G Voykov, GK Lumpkin, AH Yang, BX TI Derivation of e-beam emittances based on undulator radiation SO NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA B-GENERAL PHYSICS RELATIVITY ASTRONOMY AND MATHEMATICAL PHYSICS AND METHODS LA English DT Article ID ELECTRON-BEAM; BRIGHTNESS AB We present a method to extract the e-beam emittances from undulator brightness data. The analysis is based on the Newton method and on a stochastic procedure for the solution of a non-linear system of algebraic equations. The algorithm is shown to be stable and its reliability is tested by performing the analysis with the data available from the advanced photon source. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Dattoli, G (reprint author), ENEA,DEPT INNOVAZ,DIV FIS APPLICATA,CP 65,I-00044 FRASCATI,ITALY. NR 15 TC 0 Z9 0 U1 0 U2 0 PU EDITRICE COMPOSITORI BOLOGNA PI BOLOGNA PA VIA STALINGRADO 97/2, I-40128 BOLOGNA, ITALY SN 0369-3554 J9 NUOVO CIMENTO B JI Nouvo Cimento Soc. Ital. Fis. B-Gen. Phys. Relativ. Astron. Math. Phys. Methods PD MAY PY 1997 VL 112 IS 5 BP 733 EP 749 PG 17 WC Physics, Multidisciplinary SC Physics GA XF074 UT WOS:A1997XF07400005 ER PT J AU Huston, MA AF Huston, MA TI Hidden treatments in ecological experiments: Re-evaluating the ecosystem function of biodiversity SO OECOLOGIA LA English DT Review DE species diversity; experiment; productivity; stability; resources ID PARK-GRASS-EXPERIMENT; SPECIES RICHNESS; TERRESTRIAL ECOSYSTEMS; HERBACEOUS VEGETATION; PLANT-COMMUNITIES; DIVERSITY; STABILITY; COMPETITION; NITROGEN; SUCCESSION AB Interactions between biotic and abiotic processes complicate the design and interpretation of ecological experiments. Separating causality from simple correlation requires distinguishing among experimental treatments, experimental responses, and the many processes and properties that are correlated with either the treatments or the responses, or both. When an experimental manipulation has multiple components, but only one of them is identified as the experimental treatment. erroneous conclusions about cause and effect relationships are likely because the actual cause of any observed response may be ignored in the interpretation of the experimental results. This unrecognized cause of an observed response can be considered a ''hidden treatment.'' Three types of hidden treatments are potential problems in biodiversity experiments: (1) abiotic conditions, such as resource levels, or biotic conditions, such as predation, which are intentionally or unintentionally altered in order to create differences in species numbers for ''diversity'' treatments; (2) non-random selection of species with particular attributes that produce treatment differences that exceed those due to ''diversity'' alone; and (3) the increased statistical probability of including a species with a dominant negative or positive effect (e.g., dense shade, or nitrogen fixation) in randomly selected groups of species of increasing number or ''diversity.'' In each of these cases, treatment responses that are actually the result of the ''hidden treatment'' may be inadvertently attributed to variation in species diversity. Case studies re-evaluating three different types of biodiversity experiments demonstrate that the increases found in such ecosystem properties as productivity, nutrient use efficiency, and stability (all of which were attributed to higher levels of species diversity) were actually caused by ''hidden trearments'' that altered plant biomass and productivity. RP Huston, MA (reprint author), OAK RIDGE NATL LAB, DIV ENVIRONM SCI, POB 2008, OAK RIDGE, TN 37831 USA. RI Huston, Michael/B-1434-2009 OI Huston, Michael/0000-0001-9513-1166 NR 93 TC 1033 Z9 1119 U1 39 U2 340 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0029-8549 J9 OECOLOGIA JI Oecologia PD MAY PY 1997 VL 110 IS 4 BP 449 EP 460 DI 10.1007/s004420050180 PG 12 WC Ecology SC Environmental Sciences & Ecology GA XD210 UT WOS:A1997XD21000001 PM 28307235 ER PT J AU Siders, CW Taylor, AJ Downer, MC AF Siders, CW Taylor, AJ Downer, MC TI Multipulse interferometric frequency-resolved optical gating: Real-time phase-sensitive imaging of ultrafast dynamics SO OPTICS LETTERS LA English DT Article AB We demonstrate a powerful new tool for real-time single-shot imaging of ultrafast phase shifts based on multipulse interferometric frequency-resolved optical gating that can directly measure and display ultrafast-time-scale phase shifts without computation. In addition, this technique can, with the application of interferogram analysis and iterative phase-retrievial techniques, recover the intensity and phase of three pulses in a single shot and exhibits a linear sensitivity to the pulse field in the wings. (C) 1997 Optical Society of America. C1 UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712. RP Siders, CW (reprint author), LOS ALAMOS NATL LAB,MS D429,LOS ALAMOS,NM 87545, USA. NR 10 TC 16 Z9 16 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 1 PY 1997 VL 22 IS 9 BP 624 EP 626 DI 10.1364/OL.22.000624 PG 3 WC Optics SC Optics GA WW161 UT WOS:A1997WW16100016 PM 18185611 ER PT J AU Vairavamurthy, MA Manowitz, B Maletic, D Wolfe, H AF Vairavamurthy, MA Manowitz, B Maletic, D Wolfe, H TI Interactions of thiols with sedimentary particulate phase: studies of 3-mercaptopropionate in salt marsh sediments from Shelter Island, New York SO ORGANIC GEOCHEMISTRY LA English DT Article; Proceedings Paper CT 221st National Meeting of the American-Chemical-Society CY MAR 24-28, 1996 CL NEW ORLEANS, LA SP Amer Chem Soc DE thiol; organic sulfur; humic substances; 3-mercaptopropionate; DMSP; Spartina alterniflora; sulfur cross-linking; biodegradation; organic matter preservation; XANES; salt marsh sediments ID COASTAL MARINE-SEDIMENTS; ORGANIC-MATTER; ORGANOSULFUR COMPOUNDS; SULFUR ENRICHMENT; DIMETHYL SULFIDE; FLASH PYROLYSIS; METHANE THIOL; PERU MARGIN; AMINO-ACIDS; DIMETHYLSULFONIOPROPIONATE AB 3-Mercaptopropionate (3-MPA) is a major hydrophilic thiol in salt marsh sediments from Shelter island, New York. It is associated mainly with the sedimentary particulate phase, although the mechanism of its binding has not been clear. In this study, we show that humic substances coated on clay minerals are involved in binding 3-MPA through di- and poly-sulfide linkages. With increasing depth, the abundance of 3-MPA in the fulvic acid fraction decreases with a concomitant increase in the humic acid fraction, suggesting that, with depth, fulvic-bound 3-MPA is converted into humic-bound 3-MPA. We modeled the depth variation with a multi-G model which suggests that there are two types of reactive components in both fulvic acid-bound and humic acid-bound 3-MPA, one changing about 10 times more rapidly than the other. These two 3-MPA pools probably reflect different types of sulfur bridging, with the polysulfide-bridged pool changing more rapidly than the disulfide-bridged pool. As free thiol, 3-MPA is attacked relatively rapidly by anaerobic bacteria, its degradation following first-order kinetics. However, in the sediment core we studied, humic-bound 3-MPA was present throughout the sediment column, down to 22 cm, corresponding to an age of about 90 years. These results suggest that thiols can escape bacterial degradation in sediments by binding to humic substances. The sedimentary distribution of 3-MPA is an important illustration of the interplay of biological and chemical processes in the fate of thiols in anoxic marine sediments. (C) 1997 Elsevier Science Ltd. RP Vairavamurthy, MA (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,GEOCHEM PROGRAM,UPTON,NY 11973, USA. NR 55 TC 13 Z9 13 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0146-6380 J9 ORG GEOCHEM JI Org. Geochem. PD MAY-JUN PY 1997 VL 26 IS 9-10 BP 577 EP 585 DI 10.1016/S0146-6380(97)00019-3 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA YL289 UT WOS:A1997YL28900006 ER PT J AU Crombie, MK Arvidson, RE Sturchio, NC ElAlfy, Z AbuZeid, K AF Crombie, MK Arvidson, RE Sturchio, NC ElAlfy, Z AbuZeid, K TI Age and isotopic constraints on Pleistocene pluvial episodes in the Western Desert, Egypt SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article DE Egypt; quaternary; oxygen isotopes; uranium-series disequilbrium; travertine; Libyan desert ID DATED CORAL REEFS; RED-SEA; URANIUM; FRACTIONATION; TRAVERTINES; VARIABILITY; CARBONATES; INSOLATION; MONSOON; WATER AB North Africa has undergone drastic climatic changes over the past several hundred thousand years, The timing of humid intervals called pluvials was investigated by uranium-series disequilibrium dating of travertines from the Kurkur Oasis. Western Desert. Egypt. The youngest and best dated travertines (70-160 ka) are found in Wadi Kurkur and include spring and lacustrine units exposed as 2 to 3 m high terraces. Travertines having an age of approximately 191-220 ka are exposed by differential erosion as linear mounds produced by spring systems over fracture zones in ancient wadis. The oldest travertines, having ages >260 ka, are extensive, cap limestone units above the oasis, and were deposited in paludal and lacustrine environments. Oxygen isotope ratios were measured for the wadi travertines (delta(18)O values ranging from 16.7 to 19.1 parts per thousand SMOW) and for spring mound travertines (18.5-20.5 parts per thousand). Equilibrium oxygen isotope fractionation calculations indicate that the Kurkur travertines were deposited from waters having delta(18)O values similar to ancient Western Desert groundwaters (similar to -11 parts per thousand, Sonntag er al., 1978a.b: Thorweithe, 1990: Sultan et al., 1996). The ages of the travertines correspond to times of monosonal maxima, eustatic sea level high stands and interglacial maxima. Rainfall producing these groundwaters (and travertines) was significantly fractionated during atmospheric transport, in contrast to modern meteoric waters (-2.09 parts per thousand, Joseph et al., 1992), implying a distant source for the pluvial waters. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch insolation cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during interglacial time periods. (C) Elsevier Science B.V. C1 ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439. EGYPTIAN GEOL SURVEY & MIN AUTHOR,CAIRO,EGYPT. RP Crombie, MK (reprint author), WASHINGTON UNIV,DEPT EARTH & PLANETARY SCI,MCDONNELL CTR SPACE SCI,ST LOUIS,MO 63130, USA. NR 38 TC 50 Z9 50 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD MAY PY 1997 VL 130 IS 1-4 BP 337 EP 355 DI 10.1016/S0031-0182(96)00134-4 PG 19 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA XE566 UT WOS:A1997XE56600016 ER PT J AU Nagel, LJ Fultz, B Robertson, JL AF Nagel, LJ Fultz, B Robertson, JL TI Vibrational entropies of phases of Co3V measured by inelastic neutron scattering and cryogenic calorimetry SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID 1ST-PRINCIPLES CALCULATION; LATTICE-VIBRATIONS; DISORDERED NI3AL; ALLOYS; CU AB The difference in heat capacity of the L1(2) and hP24 phases of Co3V was measured by calorimetry at temperatures from 80 to 320 K. Inelastic neutron scattering measurements were performed on Co3V with the L1(2), hP24 and fcc phases at elevated temperatures, and the neutron-energy-loss spectra were converted into phonon density-of-states (DOS) curves. Heat capacities calculated from the L1(2) and hP24 DOS curves were approximately consistent with the calorimetry data. The phonon DOS curves showed a significant dependence on temperature, although not the temperature dependence of the simple Gruneisen approximation. The thermal expansion of the hP24 phase was measured and was interpreted adequately from the temperature dependence of the phonon DOS. By interpreting our cryogenic calorimetry data with a harmonic model, we estimate the difference in vibrational entropy of the L1(2) and hP24 phases to be (0.12 +/- 0.03)k(B) atom(-1) at low temperatures, with the L1(2) phase having the larger vibrational entropy. From the phonon DOS curves of the L1(2) phase at 898 K and the fcc phase at 1333 K, we found this difference in vibrational entropy to be (0.15 +/- 0.02)k(B) atom(-1). Phonon softening caused the entropy of the hP24 phase to increase by about 0.055 k(B) atom(-1) per 100 K. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Nagel, LJ (reprint author), CALTECH,DIV ENGN & APPL SCI,MAIL 138-78,PASADENA,CA 91125, USA. NR 30 TC 9 Z9 9 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD MAY PY 1997 VL 75 IS 5 BP 681 EP 699 DI 10.1080/13642819708202349 PG 19 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA WX943 UT WOS:A1997WX94300007 ER PT J AU Zhu, YM Tafto, J AF Zhu, YM Tafto, J TI Measurement of charge transfer in YBa2Cu3O7 using a novel electron diffraction method SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID RAY-ABSORPTION SPECTROSCOPY; TEMPERATURE; SUPERCONDUCTORS; REFINEMENT; PARAMETERS; PHASE AB We present a novel experimental approach, based on electron diffraction, of determining the amplitudes and phases of Bragg reflections at low angles. This technique was used to measure charge transfer in YBa2Cu3O7. The determined value of the structure factor of the (001) reflection, which is very sensitive to the distribution of valence electron in the crystal unit cell, corresponds in the purely ionic model to 76 +/- 8% of the electron holes being located in the CuO2 planes of fully oxygenated samples. C1 UNIV OSLO,DEPT PHYS,N-0316 BLINDERN,OSLO,NORWAY. RP Zhu, YM (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 21 TC 14 Z9 15 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD MAY PY 1997 VL 75 IS 5 BP 785 EP 791 DI 10.1080/13642819708202354 PG 7 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA WX943 UT WOS:A1997WX94300012 ER PT J AU Laible, PD Zhang, YN Morris, AL Snyder, SW Ainsworth, C Greenfield, SR Wasielewski, MR Parot, P Schoepp, B Schiffer, M Hanson, DK Thurnauer, MC AF Laible, PD Zhang, YN Morris, AL Snyder, SW Ainsworth, C Greenfield, SR Wasielewski, MR Parot, P Schoepp, B Schiffer, M Hanson, DK Thurnauer, MC TI Spectroscopic characterization of quinone-site mutants of the bacterial photosynthetic reaction center SO PHOTOSYNTHESIS RESEARCH LA English DT Article DE electron paramagnetic resonance; electron spin polarization; quinone binding; revertant isolation; electrostatics ID REACTION CENTER PROTEIN; R-26 REACTION CENTERS; RHODOBACTER-SPHAEROIDES; ELECTRON-TRANSFER; BINDING-SITE; RHODOPSEUDOMONAS-SPHAEROIDES; CHARGE RECOMBINATION; LOW-TEMPERATURE; TRIPLET-STATE; BACTERIOCHLOROPHYLL AB Site-specific mutations in the quinone binding sites of the photosynthetic reaction center (RC) protein complexes of Rhodobacter (R.) capsulatus caused pronounced effects on sequential electron transfer. Conserved residues that break the twofold symmetry in this region of the RC - M246Ala and M247Ala in the Q(A) binding pocket, and L212Glu and L213Asp in the Q(B) binding pocket - were targeted. We constructed a Q(B)-site mutant, L212Glu-L213Asp --> Ala-Ala, and a Q(A)-site mutant, M246Ala-M247Ala --> Glu-Asp, to partially balance the differences in charge distribution normally found between the two quinone binding sites. In addition, two photocompetent revertants were isolated from the photosynthetically-incompetent M246Glu-M247Asp mutant: M246Ala-M247Asp and M246Gly-M247Asp. Sequential electron transfer was investigated by continuous light excitation and time-resolved electron paramagnetic resonance (EPR), and time-resolved optical techniques. Several lines of EPR evidence suggested that the forward electron transfer rate to Q(A), k(Q), was slowed in those strains containing altered Q(A) sites. The slower rates of secondary electron transfer were confirmed by time-resolved optical results with the M246Glu-M247Asp mutations in the Q(A) site resulting in a dramatically lowered secondary electron transfer efficiency [k(Q) < (2 ns)(-1)] in comparison with either the native R. capsulatus RC or the Q(B) site mutant [k(Q) approximate to (200 ps)(-1)]. Secondary electron transfer in the two revertants was intermediate between that of the native RC and the Q(A) mutant. The P(+)Q(A) --> PQ(A) charge recombination rates were also changed in the strains that carried altered Q(A) sites. We show that local mutations in the Q(A) site, presumably through local electrostatic changes, significantly alter binding and electron transfer properties of Q(A). C1 ARGONNE NATL LAB,CTR MECH BIOL & BIOTECHNOL,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NORTHWESTERN UNIV,DEPT CHEM,EVANSTON,IL 60208. CE CADARACHE,CEA DPVE,F-13108 ST PAUL DURANCE,FRANCE. RI PAROT, Pierre/B-3959-2012; PAROT, Pierre/C-1742-2017; OI Snyder, Seth/0000-0001-6232-1668 NR 48 TC 11 Z9 11 U1 0 U2 4 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 MAY PY 1997 VL 52 IS 2 BP 93 EP 103 DI 10.1023/A:1005806700335 PG 11 WC Plant Sciences SC Plant Sciences GA XV412 UT WOS:A1997XV41200003 ER PT J AU Saxena, A Wu, Y Lookman, T Shenoy, SR Bishop, AR AF Saxena, A Wu, Y Lookman, T Shenoy, SR Bishop, AR TI Hierarchical pattern formation in elastic materials SO PHYSICA A LA English DT Article; Proceedings Paper CT Proceedings of the International Conference on Pattern Formation in Fluids and Materials CPiP 96 (Collective Phenomena in Physics 96) CY JUN 13-15, 1996 CL UNIV WESTERN ONTARIO, LONDON, CANADA HO UNIV WESTERN ONTARIO ID MARTENSITIC TRANSFORMATIONS; SPINODAL DECOMPOSITION; PHASE-SEPARATION; TWIN BOUNDARIES; TWEED; YBA2CU3O7-DELTA; PRECURSORS; DYNAMICS; KINETICS; SYSTEMS AB We study hierarchical structures such as branched twins in elastic materials based on a model of martensitic materials in which hierarchical twinning near the habit plane (austenite-martensite interface) is a new and crucial ingredient. The model includes (1) a triple-well potential ((phi(0) model) in local strain, (2) strain gradient terms up to second order in strain and fourth-order in gradient, and (3) all symmetry-allowed compositional fluctuation-induced strain gradient terms which favor hierarchical structures and enable communication between macroscopic (cm) and microscopic ik) regions essential for shape memory. Below the transition temperature (T-0) we obtain the conditions under which branching of twins is energetically favorable. This hierarchy of length scales provides a related hierarchy of time scales and thus the possibility of non-exponential decay. Results based on 2D simulations of the time-dependent Ginzburg-Landau (TDGL) equation are shown for twins, tweed and hierarchy formation. We also apply stability analysis to study the formation of modulated structures at early time and obtain an approximate phase diagram for the model. C1 UNIV WESTERN ONTARIO,DEPT MATH APPL,LONDON,ON N6A 5B7,CANADA. UNIV HYDERABAD,SCH PHYS,HYDERABAD 500134,ANDHRA PRADESH,INDIA. INT CTR THEORET PHYS,I-34100 TRIESTE,ITALY. RP Saxena, A (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 55 TC 23 Z9 23 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 1 PY 1997 VL 239 IS 1-3 BP 18 EP 34 DI 10.1016/S0378-4371(96)00469-4 PG 17 WC Physics, Multidisciplinary SC Physics GA XE559 UT WOS:A1997XE55900004 ER PT J AU Ecke, RE Hu, YC AF Ecke, RE Hu, YC TI Spiral defect chaos in Rayleigh-Benard convection: Defect population statistics SO PHYSICA A LA English DT Article; Proceedings Paper CT Proceedings of the International Conference on Pattern Formation in Fluids and Materials CPiP 96 (Collective Phenomena in Physics 96) CY JUN 13-15, 1996 CL UNIV WESTERN ONTARIO, LONDON, CANADA HO UNIV WESTERN ONTARIO DE spatio-temporal chaos; convection; pattern formation; defects ID LOW PRANDTL NUMBER; CYLINDRICAL CONTAINER; PATTERNS; TURBULENCE; DYNAMICS; THRESHOLD; FLOW AB We report a number of observations regarding the populations of defects in the spiral-defect chaos slate of Rayleigh-Benard convection, The experiments were carried out using CO2 at 32 bar with a Prandtl number sigma=0.98 in a cylindrical convection cell with radius-to-height ratio Gamma=52. The populations of spirals, targets, and sidewall foci were measured as functions of epsilon=Delta T/Delta T-c-1 and were used to describe the transition to spiral-defect chaos. The probability distributions of the number and size of defects were determined and compared to Poisson and Gaussian distributions. The populations of spirals were further characterized by size and sense of winding (clockwise or counterclockwise) and the normalized difference is presented as a function of E. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Ecke, RE (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. OI Ecke, Robert/0000-0001-7772-5876 NR 31 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 1 PY 1997 VL 239 IS 1-3 BP 174 EP 188 DI 10.1016/S0378-4371(97)00026-5 PG 15 WC Physics, Multidisciplinary SC Physics GA XE559 UT WOS:A1997XE55900020 ER PT J AU Pellegrini, M GronbechJensen, N Doniach, S AF Pellegrini, M GronbechJensen, N Doniach, S TI Simulations of the thermodynamic properties of a short polyalanine peptide using potentials of mean force SO PHYSICA A LA English DT Article; Proceedings Paper CT Proceedings of the International Conference on Pattern Formation in Fluids and Materials CPiP 96 (Collective Phenomena in Physics 96) CY JUN 13-15, 1996 CL UNIV WESTERN ONTARIO, LONDON, CANADA HO UNIV WESTERN ONTARIO ID ALANINE-BASED PEPTIDES; HELIX-COIL TRANSITION; ALPHA-HELICES; DYNAMICS; PARAMETERS AB We report results of simulation studies of the equilibrium between helical and random coil states of dodeca-alanine by a method which systematically includes the effects of hydration. The statistical distribution of conformations at room temperature is determined and used to fit thermodynamic parameters for the helix to random coil equilibrium which may be directly compared with experimental data. The distribution of conformations is explored at atomic resolution by a constrained Langevin-dynamics simulated annealing technique which limits the effective number of degrees of freedom to two per residue. Water is included via a set of pair potentials of mean force. We show that the inclusion of hydration effects is essential for achieving a helical content comparable to that found experimentally. However, the cooperative nature of the helical state Found in the simulations is low compared to the experimental value. C1 UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90024. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV CALIF LOS ANGELES,INST MOL BIOL,LOS ANGELES,CA 90095. STANFORD UNIV,DEPT APPL PHYS,STANFORD,CA 94305. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. NR 15 TC 10 Z9 10 U1 3 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 1 PY 1997 VL 239 IS 1-3 BP 244 EP 254 DI 10.1016/S0378-4371(96)00483-9 PG 11 WC Physics, Multidisciplinary SC Physics GA XE559 UT WOS:A1997XE55900027 ER PT J AU He, XY Luo, LS Dembo, M AF He, XY Luo, LS Dembo, M TI Some progress in the lattice Boltzmann method: Reynolds number enhancement in simulations SO PHYSICA A LA English DT Article; Proceedings Paper CT Proceedings of the International Conference on Pattern Formation in Fluids and Materials CPiP 96 (Collective Phenomena in Physics 96) CY JUN 13-15, 1996 CL UNIV WESTERN ONTARIO, LONDON, CANADA HO UNIV WESTERN ONTARIO DE lattice Boltzmann method; high Reynolds number simulation; nonuniform mesh grids; flow in 2-D symmetric channel with sudden expansion ID FLOW AB A newly proposed lattice Boltzmann algorithm is used to simulate flows with high Reynolds number, The new algorithm is not limited by the lattice Reynolds number which constrains all previous lattice Boltzmann models. Not only is the Reynolds number enhanced in the simulation using the new algorithm but also is the numerical stability improved significantly, Numerical simulations of the Bow in a 2-D symmetrical sudden expansion were conducted to demonstrate the effectiveness of the new algorithm. C1 NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,THEORET BIOL & BIOPHYS GRP T10,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,COMPLEX SYST GRP T13,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,COMPUTAT SCI METHODS GRP XCM,APPL THEORET & COMPUTAT PHYS DIV,LOS ALAMOS,NM 87545. NASA,LANGLEY RES CTR,ICASE,HAMPTON,VA 23681. RI Dembo, Micah/C-2755-2013; Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 9 TC 42 Z9 46 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 1 PY 1997 VL 239 IS 1-3 BP 276 EP 285 DI 10.1016/S0378-4371(96)00486-4 PG 10 WC Physics, Multidisciplinary SC Physics GA XE559 UT WOS:A1997XE55900030 ER PT J AU Diko, P Todt, VR Miller, DJ Goretta, KC AF Diko, P Todt, VR Miller, DJ Goretta, KC TI Subgrain formation, 211 particle segregation and high-angle 90 degrees boundaries in melt-grown YBaCuO SO PHYSICA C LA English DT Article DE melt-processed YBaCuO; microstructure; grains and subgrains; Y2BaCuO5; particle segregation ID CRITICAL CURRENTS; SUPERCONDUCTORS; MICROSTRUCTURE AB Microstructural features such as subgrains, Y2BaCuO5 particles, and high-angle boundaries were studied in single- and multiple-domain melt-textured YBaCuO levitators. Subgrains elongated in the c- or a-direction and rectangular in cross section were formed during solidification by cellular growth. Formation of subgrains by combination of a- and c-growth was also observed. Their boundaries were predominantly low-angle, and were not cracked or wetted by second phases. Macrosegregation of Y2BaCuO5 particles developed mainly in the regions formed by c-axis growth. The segregation is related to Y2BaCuO5 particle pushing by the YBa2Cu3O7-x growth front. The structure of 90 degrees high-angle grain boundaries appeared to be similar to that of the low-angle grain boundaries. (C) 1997 Elsevier Science B.V. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV ENERGY TECHNOL,ARGONNE,IL 60439. ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. RP Diko, P (reprint author), SLOVAK ACAD SCI,INST EXPT PHYS,KOSICE 04353,SLOVAKIA. NR 22 TC 28 Z9 28 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 1 PY 1997 VL 278 IS 3-4 BP 192 EP 200 DI 10.1016/S0921-4534(97)00113-5 PG 9 WC Physics, Applied SC Physics GA XD061 UT WOS:A1997XD06100007 ER PT J AU Carraro, L Mattioli, M Sattin, F Demichelis, C Hogan, JT Mandl, W Puiatti, ME Scarin, P Valisa, M AF Carraro, L Mattioli, M Sattin, F Demichelis, C Hogan, JT Mandl, W Puiatti, ME Scarin, P Valisa, M TI Collisional-radiative models for hydrogen-like and helium-like carbon and oxygen ions and applications to experimental data from the TS tokamak and the reversed field pinch RFX SO PHYSICA SCRIPTA LA English DT Article ID HE-LIKE IONS; PERTURBED STATIONARY STATES; ELECTRON-IMPACT EXCITATION; CAPTURE CROSS-SECTIONS; EQUAL-TO 5; RATE COEFFICIENTS; RECOMMENDED DATA; FINE-STRUCTURE; ISOELECTRONIC SEQUENCE; RELATIVE INTENSITIES AB Collisional radiative models (CRM) are needed to simulate experimental line brightnesses and emissivities from fusion devices. CRM are built for H-like and He-like carbon and oxygen ions, following a detailed review of the published literature on the required atomic data (including both collision rate coefficients and atomic transition probabilities). The impurity ion radial distribution is obtained using a transport code with two radius dependent transport parameters: a diffusion coefficient D and an inward convection velocity V. Reliable atomic data are a prerequisite to these simulations, since they are supposed to be well known; adjustement of the simulations to the experimental line and/or continuum brightnesses and emissivities is done by varying only D and V. Examples are given of the quantitative interpretation of experimental spectroscopic data from two fusion devices: the Tore Supra Tokamak and the Reversed Field Pinch RFX. As a consequence of the order of magnitude difference in the central electron temperatures in the two devices, the sensitivity of the H-like and He-like ion emissions to the transport parameters is different. These differences are highlighted in the examples given. C1 CEN CADARACHE, DEPT RECH FUS CONTROLEE, EURATOM ASSOC, CEA FUS, F-13108 ST PAUL LES DURANCE, FRANCE. OAK RIDGE NATL LAB, DIV FUS ENERGY, OAK RIDGE, TN 37831 USA. RP Carraro, L (reprint author), UNIV PADUA ASSOC, ENEA EURATOM CNR, GRP PADOVA RIC FUS, CORSO STATI UNITI 4, I-35127 PADUA, ITALY. RI Sattin, Fabio/B-5620-2013 NR 61 TC 12 Z9 12 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0031-8949 EI 1402-4896 J9 PHYS SCRIPTA JI Phys. Scr. PD MAY PY 1997 VL 55 IS 5 BP 565 EP 578 DI 10.1088/0031-8949/55/5/009 PG 14 WC Physics, Multidisciplinary SC Physics GA WY775 UT WOS:A1997WY77500009 ER PT J AU Shukla, A Dolg, M Flad, HJ Banerjee, A Mohanty, AK AF Shukla, A Dolg, M Flad, HJ Banerjee, A Mohanty, AK TI Relativistic configuration-interaction study of valence-electron correlation effects on the fine-structure splitting in the Pb isoelectronic series SO PHYSICAL REVIEW A LA English DT Article ID BASIS-SET CALCULATIONS; HARTREE-FOCK CALCULATIONS; COUPLED-CLUSTER METHOD; ATOMIC SYSTEMS; DIRAC-EQUATION; PERTURBATION-THEORY; BREIT INTERACTION; ROOTHAAN THEORY; PROGRAM; STATES AB Relativistic large-scale multireference configuration-interaction all-electron calculations, used to study the influence of valence-electron correlation effects on the fine-structure splittings in the Pb atom and the isoelectronic ions Bi+ and Po2+, are presented. The atomic nucleus was modeled as a finite, uniformly charged sphere. The one-electron basis set consisted of orbitals expressed as a linear combination of kinetically balanced Gaussian basis functions. All four valence electrons were correlated by considering excitations from the 6s(2)6p(2) configurations and systematically enlarging the virtual space to include unoccupied orbitals of symmetries up to f(7/2). The results obtained are in good agreement with experimental data, and remaining disagreements are largely attributed to missing core-valence correlation effects. Comparisons with the results of variational quantum Monte Carlo and multireference configuration-interaction studies based on the relativistic pseudopotential approach are also presented. C1 EG&G IDAHO INC,IDAHO NATL ENGN LAB,THEORY PROJECT,IDAHO FALLS,ID 83415. IBM CORP,DIV 6000,RISC SYST,POUGHKEEPSIE,NY 12601. RP Shukla, A (reprint author), MAX PLANCK INST PHYS KOMPLEXER SYST,BAYREUTHER STR 40,D-01187 DRESDEN,GERMANY. RI Dolg, Michael/F-8716-2011 NR 57 TC 7 Z9 7 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 1997 VL 55 IS 5 BP 3433 EP 3439 DI 10.1103/PhysRevA.55.3433 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200025 ER PT J AU Chen, MH Cheng, KT AF Chen, MH Cheng, KT TI Large-scale relativistic configuration-interaction calculation of the 3s(2) S-1(0)-3s3p P-1,3(1) transition energies in magnesiumlike ions SO PHYSICAL REVIEW A LA English DT Article ID HELIUM-LIKE IONS; PERTURBATION-THEORY CALCULATIONS; I ISOELECTRONIC SEQUENCE; LAMB-SHIFT CALCULATIONS; MG-LIKE IONS; OSCILLATOR-STRENGTHS; SELF-ENERGY; NA-LIKE; 2S(1/2)-2P(3/2) LEVELS; RESONANCE TRANSITIONS AB We have calculated the 3s(2 1)S(0)-3s3p(1,3)P(1) transition energies for neutral magnesium and Mg-like Ar6+, Cu17+, Kr24+, and Mo30+ using the relativistic configuration-interaction (CI) method. These calculations are based on the relativistic no-pair Hamiltonian which includes Coulomb and retarded Breit interactions and employ finite B-spline basis functions. Quantum electrodynamic and mass polarization corrections are also calculated. For Mg-like ions studied here, intravalence correlations are treated exactly by saturating the basis with all configurations that arise from valence-valence excitations. Contributions from core polarization are also calculated with large-scale CI expansions by including dominant configurations from core-valence excitations. Agreement between theory and experiment are good for all the Mg-like ions studied here. RP Chen, MH (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 48 TC 34 Z9 37 U1 0 U2 0 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 MAY PY 1997 VL 55 IS 5 BP 3440 EP 3446 DI 10.1103/PhysRevA.55.3440 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200026 ER PT J AU Pieksma, M Bannister, ME Wu, W Havener, CC AF Pieksma, M Bannister, ME Wu, W Havener, CC TI Low-energy electron capture by N2+ ions from atomic hydrogen using merged beams SO PHYSICAL REVIEW A LA English DT Article ID CROSS-SECTIONS; MOLECULAR-HYDROGEN; CHARGE-TRANSFER; H-ATOMS; SLOW; COLLISIONS; IONIZATION; N-2+ AB Using the merged-beams technique, independent, absolute, total electron-capture cross sections have been measured for the N2+ + H (or D) system in the collision energy range 0.1-4500 eV/amu. For collision energies less than 200 eV/amu, the data are in reasonable accord with recent fully quantal calculations of Herrero et al. [J. Phys. B 28, 711 (1995)], except that the experiment provides no evidence for the existence of a peak in the cross section at 0.25 eV/amu. Additional structure between 10 and 100 eV/amu, as predicted by Bienstock et al. [Phys. Rev. A 33, 2078 (1986)], is not observed either. A comparison is also made with other measurements, which make use of a hydrogen furnace [Phaneuf er al., Phys. Rev. A 17, 534 (1978); Seim et al., J. Phys. B 14, 3475 (1981); Wilkie et al., J. Phys. B 18, 479 (1985)]. Above 2000 eV/amu the agreement is excellent. However, between 200 and 2000 eV/amu the present results are some 30% below the previously published experimental and theoretical cross sections, and a local maximum is found near 200 eV/amu, instead of 360 eV/amu. A possible explanation for this discrepancy is suggested. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. OI Bannister, Mark E./0000-0002-9572-8154 NR 19 TC 13 Z9 13 U1 0 U2 0 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 MAY PY 1997 VL 55 IS 5 BP 3526 EP 3531 DI 10.1103/PhysRevA.55.3526 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200037 ER PT J AU Ovchinnikov, SY Macek, JH AF Ovchinnikov, SY Macek, JH TI Positive energy sturmian states for two-Coulomb-center problems SO PHYSICAL REVIEW A LA English DT Article ID GREEN-FUNCTION; EXPANSION; COLLISIONS; IONIZATION; HYDROGEN AB Properties of two-center Coulomb Sturmian basis sets are discussed. Analytic and numerical techniques to calculate these functions and coupling matrix elements are developed. A class of Sturmian functions is found that has no analytic continuation to negative energies and is not present in one-center potentials. Advantages of Sturmian sets over conventional eigenstate sets are emphasized. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. AF IOFFE PHYS TECH INST,ST PETERSBURG 194021,RUSSIA. RP Ovchinnikov, SY (reprint author), UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996, USA. RI Ovchinnikov, Serguei/C-4994-2014 NR 11 TC 26 Z9 26 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 MAY PY 1997 VL 55 IS 5 BP 3605 EP 3614 DI 10.1103/PhysRevA.55.3605 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200046 ER PT J AU Briand, JP Schneider, D Bardin, S Khemliche, H Jin, J Xie, Z Prior, M AF Briand, JP Schneider, D Bardin, S Khemliche, H Jin, J Xie, Z Prior, M TI X-ray studies of the interaction of N, O, and Ne hydrogenlike ions below surfaces SO PHYSICAL REVIEW A LA English DT Article AB We present in this paper some experiments on the interaction of slow N6+, O7+, and Ne9+ ions below C or Si surfaces carried out by looking at the projectile and target x rays. The study of the x rays emitted by the ions, in contrast with studies of Auger electrons, allows the observation of a much larger part of the decay, not yet explored, below the surface. Moreover, the x rays emitted by the target atoms may identify the shell from which the electrons are captured. It is shown that the electron promotion mechanism, previously observed, which transfers, e.g., K electrons of C targets into the L shell of these ions, represents only a very small part of the interactions occurring at the first atomic layer and that the neutralization takes place, below the surface, mainly via Auger neutralization. C1 UNIV PARIS 06,NUCL INST RADIUM,ERS CNRS 112,F-75252 PARIS 05,FRANCE. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Briand, JP (reprint author), UNIV PARIS 06,LAB PHYS ATOM,4 PL JUSSIEU,F-75252 PARIS 05,FRANCE. NR 10 TC 21 Z9 21 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 MAY PY 1997 VL 55 IS 5 BP 3947 EP 3950 DI 10.1103/PhysRevA.55.3947 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200087 ER PT J AU Kilper, DC Roos, PA Carlsten, JL Lear, KL AF Kilper, DC Roos, PA Carlsten, JL Lear, KL TI Squeezed light generated by a microcavity laser SO PHYSICAL REVIEW A LA English DT Article ID SURFACE EMITTING LASERS; QUANTUM-WELL LASERS; SEMICONDUCTOR-LASER; SPONTANEOUS EMISSION; NOISE; POLARIZATION; OSCILLATOR AB Photon-number fluctuations 1.3 dB below the semiclassical shot-noise limit are observed in the output of a semiconductor microcavity laser. Although the laser oscillates in a single longitudinal mode, photon-number squeezed light is realized through nonclassical correlations between two orthogonally polarized, transverse laser modes. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Kilper, DC (reprint author), MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717, USA. NR 24 TC 48 Z9 48 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 MAY PY 1997 VL 55 IS 5 BP R3323 EP R3326 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200010 ER PT J AU Ohnishi, A Randrup, J AF Ohnishi, A Randrup, J TI Quantum fluctuations affect the critical properties of noble gases SO PHYSICAL REVIEW A LA English DT Article ID MOLECULAR-DYNAMICS; FRAGMENTATION; LIQUIDS AB Interacting argon atoms are simulated with a recently developed quantum Langevin transport treatment that takes approximate account of the quantum fluctuations inherent in microscopic many-body descriptions based on wave packets. The mass distribution of the atomic clusters is affected significantly near the critical temperature and thus it may be important to take account of quantum fluctuations in molecular-dynamics simulations of cluster formation processes. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. RP Ohnishi, A (reprint author), HOKKAIDO UNIV,FAC SCI,DEPT PHYS,SAPPORO,HOKKAIDO 060,JAPAN. RI Ohnishi, Akira/F-7403-2011 OI Ohnishi, Akira/0000-0003-1513-0468 NR 15 TC 10 Z9 10 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 1997 VL 55 IS 5 BP R3315 EP R3318 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA WX952 UT WOS:A1997WX95200008 ER PT J AU Saxena, A Dandoloff, R AF Saxena, A Dandoloff, R TI Curvature-induced geometrical frustration in magnetic systems SO PHYSICAL REVIEW B LA English DT Article ID TOPOLOGICAL SOLITONS; SPACE CURVES; SIGMA-MODEL; INSTABILITY AB We study classical Heisenberg spins in the continuum limit (i.e., the nonlinear a model) on an elastic two-dimensional manifold with at least one nonconstant principal curvature. If the corresponding Euler-Lagrange equations support a soliton solution, the nonconstant curvature of the geometry induces geometrical frustration in the region of the soliton which is relieved by a deformation of the manifold in the region of the soliton. We illustrate these results on an elliptic cylinder where we find an elastic soliton in terms of the variable ellipticity along the axis of the cylinder. C1 UNIV CERGY PONTOISE,GRP PHYS STAT,F-95302 CERGY,FRANCE. RP Saxena, A (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 24 TC 14 Z9 14 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11049 EP 11051 DI 10.1103/PhysRevB.55.11049 PG 3 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400014 ER PT J AU Boettger, JC AF Boettger, JC TI All-electron full-potential calculation of the electronic band structure, elastic constants, and equation of state for graphite SO PHYSICAL REVIEW B LA English DT Article ID SINGLE-CRYSTAL GRAPHITE; ULTRAVIOLET PHOTOELECTRON-SPECTROSCOPY; RESOLVED INVERSE PHOTOEMISSION; ANNEALED PYROLYTIC-GRAPHITE; TARGET-CURRENT SPECTROSCOPY; X-RAY-DIFFRACTION; INTERPLANAR BINDING; CONDUCTION-BAND; TOTAL-ENERGY; INTERCALATION COMPOUNDS AB The all-electron full-potential linear combinations of Gaussian-type orbitals-fitting-function technique has been used to calculate the electronic structure, equation of state (EOS), and elastic constants for crystalline graphite. An analysis of the zero-pressure band structure is used to resolve inconsistencies between previous local-density-approximation (LDA) calculations. The calculated band structure is consistent with experimental data to the extent expected given the known limits of LDA one-electron energies. The in-plane lattice constant found here exhibits the usual LDA-induced contraction, whereas the interlayer separation and the unit-cell volume exhibit an anomalous expansion due to a LDA underestimate of the weak interlayer bonding. The calculated values of C-11+C-12 and C-33 are in good agreement with ultrasound measurements, while the value of C-13 (approximate to 0) is much smaller than the ultrasound value. The bulk modulus and pressure derivatives of the lattice constants derived from the theoretical elastic constants are in very good agreement with diamond anvil cell (DAC) data, suggesting that the theoretical value for C-13 is more reliable than the ultrasound measurement. An analytical EOS has been determined for pressures up to 50 Gpa, well beyond the range of stability for the graphite structure. The EOS and the pressure dependencies of cia and the optical transition energies (A(1) and A(2)) are in reasonable agreement with DAC data up to 14 Gpa. RP Boettger, JC (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 70 TC 108 Z9 109 U1 0 U2 23 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11202 EP 11211 DI 10.1103/PhysRevB.55.11202 PG 10 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400045 ER PT J AU Price, DL Ellison, AJG Saboungi, ML Hu, RZ Egami, T Howells, WS AF Price, DL Ellison, AJG Saboungi, ML Hu, RZ Egami, T Howells, WS TI Short-, intermediate-, and extended-range order in rubidium germanate glasses SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-DIFFRACTION; THERMAL-EXPANSION; SCATTERING; GESE2 AB The origin of diffraction peaks observed at low wave vector in many complex glasses remains a central issue in the understanding of amorphous structures. In this work a combination of neutron and x-ray diffraction is used to correlate the contributions from the different atom pair correlations to such peaks in rubidium germanate glasses. The information obtained is compared with structural data on glasses of similar compositions from other techniques, structures of corresponding crystalline compounds, and results from computer simulation of analogous systems. C1 UNIV PENN,PHILADELPHIA,PA 19104. RUTHERFORD APPLETON LAB,CHILTON OX11 0QX,OXON,ENGLAND. RP Price, DL (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 41 TC 52 Z9 52 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11249 EP 11255 DI 10.1103/PhysRevB.55.11249 PG 7 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400051 ER PT J AU Surh, MP Runge, KJ Barbee, TW Pollock, EL Mailhiot, C AF Surh, MP Runge, KJ Barbee, TW Pollock, EL Mailhiot, C TI Ab initio calculations for solid molecular hydrogen SO PHYSICAL REVIEW B LA English DT Review ID INSULATOR-METAL TRANSITION; X-RAY-DIFFRACTION; MEGABAR PRESSURES; PHASE-TRANSITIONS; DENSE HYDROGEN; ULTRAHIGH-PRESSURE; CRYSTAL-STRUCTURE; CHARGE-TRANSFER; BAND OVERLAP; GROUND-STATE AB Ab initio calculations are used to propose a unified model for the pressure-temperature phase diagram of solid molecular hydrogen. Path integral Monte Carlo calculations model the orientational order-disorder transition of spatially symmetric molecules. Possible ordered molecular structures near 150 GPa pressure are examined in the local density approximation. It is shown that the discontinuity in the molecular vibron frequency versus pressure observed in this regime can be attributed to a combined band overlap and orientational transition. However, an orientationally inhomogeneous insulating phase may preempt the anticipated bulk transition along the 150 GPa experimental phase line. Finally, calculations suggest that the hcp semimetallic phase undergoes a martensitic transition to orthorhombic symmetry in the same region. RP LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. NR 111 TC 22 Z9 22 U1 1 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11330 EP 11341 DI 10.1103/PhysRevB.55.11330 PG 12 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400061 ER PT J AU Katsumata, K Katori, HA Shapiro, SM Shirane, G AF Katsumata, K Katori, HA Shapiro, SM Shirane, G TI Neutron-scattering studies of a phase transition in the metamagnet FeBr2 under external magnetic fields SO PHYSICAL REVIEW B LA English DT Article AB Neutron-scattering experiments have been performed on the metamagnet FeBr2 under external magnetic fields. We find an anomaly in the temperature (T) and magnetic-field (H) dependences of the intensity of the (2,0,1/2) antiferromagnetic Bragg scattering at the temperature T-1(H) at which an anomaly in specific heat has been observed in addition to the anomaly at the Neel temperature T-N(H). We argue that our results are consistent with the theoretical H-T phase diagram of a metamagnet in which the tricritical point decomposes into a critical end point and a bicritical end point. We locate the latter point at T-cr similar or equal to 10.8 K and H-cr similar or equal to 1.4 T in this compound. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Katsumata, K (reprint author), RIKEN,INST PHYS & CHEM RES,WAKO,SAITAMA 35101,JAPAN. RI Katori, Hiroko/C-8794-2013 NR 17 TC 30 Z9 32 U1 2 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11466 EP 11470 DI 10.1103/PhysRevB.55.11466 PG 5 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400078 ER PT J AU Malik, SK Menon, L Pecharsky, VK Gschneidner, KA AF Malik, SK Menon, L Pecharsky, VK Gschneidner, KA TI Effect of magnetic fields on the kondo insulator CeRhSb: Magnetoresistance and high-field heat capacity measurements SO PHYSICAL REVIEW B LA English DT Article ID ENERGY-GAP; CENISN; SYSTEM; STATE AB The compound CeRhSb is a mixed valent Ce-based compound which shows a gap in the electronic density of states at low temperatures. The gap manifests by a rise in electrical resistivity-below about 8 K from which the gap energy is estimated to be about 4 K. We have carried out heat capacity measurements on this compound in various applied fields up to 9.85 T. The magnetic contribution to the heat capacity, Delta C, is found to have a maximum in Delta C/T vs T at 10 K, below which Delta C/T is linear with T. This is attributed to the fact that below this temperature, in the gapped state, the electronic density of states decreases linearly with decreasing temperature. On application of a magnetic field, the electronic specific heat coefficient gamma in the gapped state increases by similar to 4 mJ/mol K-2. The maximum in Delta C/T vs T is observed in all fields, which shifts to lower temperatures similar to 1 K at 5.32 T and raises again at 9.85 T to about the same values as at H=0 T. This suggests that the gap exists for all fields up to 9.85 T. Above 10 K, in the mixed-valent state, Delta C/T vs T decreases with increasing temperature in zero field. There is hardly any effect of application of field in the mixed-valent state, since the applied fields are too small to change the already large density of states at the Fermi level. We have also carried out magnetoresistance measurements on CeRhSb up to fields of 5.5 T at 2, 4.5, 10, 20, and 30 K. The magnetoresistance in CeRhSb is positive at temperatures of 4.5 K and above, in applied fields up to 5.5 T. At 5.5 T, the magnetoresistance is maximum at 4.5 K (6%) and decreases with increasing temperature. The observation of the maximum is consistent with the observation of a maximum in Delta C/T vs T and is due to a change in the density of states. At a temperature of 2 K, a negative magnetoresistance is observed for magnetic fields greater than similar to 3.5 T which suggests reduction in the gap. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP Malik, SK (reprint author), TATA INST FUNDAMENTAL RES,HOMI BHABHA RD,BOMBAY 400005,MAHARASHTRA,INDIA. NR 15 TC 15 Z9 15 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11471 EP 11475 DI 10.1103/PhysRevB.55.11471 PG 5 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400079 ER PT J AU Hundley, MF Neumeier, JJ AF Hundley, MF Neumeier, JJ TI Thermoelectric power of La1-xCaxMnO3+delta: Inadequacy of the nominal Mn3+/4+ valence approach SO PHYSICAL REVIEW B LA English DT Article ID ELECTRICAL-PROPERTIES; MAGNETORESISTANCE; SEMICONDUCTOR; OXIDE; MODEL AB The temperature-dependent thermoelectric power (TEP) and resistivity of La1-xCaxMnO3+sigma polycrystals (0 less than or equal to x less than or equal to 0.45) are reported. The TEP data are analyzed within an adiabatic small polaron description in order to determine the number of charge carriers per active transport site in the paramagnetic state. The TEP in the small-polaron regime above Te is significantly smaller than that predicted by nominal Mn3+/4+ valence arguments. This indicates that more holelike charge carriers and/or fewer accessible Mn transport sites are present in these compounds than expected based on the divalent doping levels employed. This result is consistent with a substantial degree of 3d(4)-3d(4) (Mn3+-Mn3+) charge disproportionation into more stable 3d(5)-3d(3) (Mn2+-Mn4+) pairs. RP Hundley, MF (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 40 TC 138 Z9 139 U1 0 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11511 EP 11515 DI 10.1103/PhysRevB.55.11511 PG 5 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400086 ER PT J AU Yokoo, T Zheludev, A Nakamura, M Akimitsu, J AF Yokoo, T Zheludev, A Nakamura, M Akimitsu, J TI Ni-chain gap excitations in (NdxY1-x)(2)BaNiO5: One-dimensional to three-dimensional crossover SO PHYSICAL REVIEW B LA English DT Article ID HALDANE-GAP; NEUTRON-SCATTERING; COMPOUND Y2BANIO5; SPIN DYNAMICS; SIGMA-MODEL; FIELD; ANTIFERROMAGNET; SUSCEPTIBILITY; TRANSITIONS; TEMPERATURE AB Linear-chain mixed-spin antiferromagnets (NdxY1-x)(2)BaNiO5 were investigated by powder inelastic neutron scattering for x=0.25, 0.5, and x=0.75. Long-range magnetic ordering was observed in all samples. The temperature dependence of the Ni-chain spin-gap modes was measured and compared to previous results for the x=0 and x=1 materials. In the magnetically disordered phase the spin dynamics was shown to have a composition-independent character. The results suggest that one-dimensional gap excitations seen in the paramagnetic and Neel phases of Nd2BaNiO5 are inherently related to Haldane spin excitations in the quantum-disordered system Y2BaNiO5. C1 BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RP AOYAMA GAKUIN UNIV, DEPT PHYS, SETAGAYA KU, 6-16-1 CHITOSEDAI, TOKYO 157, JAPAN. NR 29 TC 33 Z9 33 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 MAY 1 PY 1997 VL 55 IS 17 BP 11516 EP 11520 DI 10.1103/PhysRevB.55.11516 PG 5 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400087 ER PT J AU Room, T Appelt, S Seydoux, R Hahn, EL Pines, A AF Room, T Appelt, S Seydoux, R Hahn, EL Pines, A TI Enhancement of surface NMR by laser-polarized noble gases SO PHYSICAL REVIEW B LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; CROSS-POLARIZATION; XENON; XE-129; SPECTROSCOPY; RELAXATION; PARTICLES; NE-21; HE-3 AB The transfer of spin polarization from laser-polarized helium and xenon to spins such as H-1 and C-13 On the surface of high-surface-area solids (Aerosil) is demonstrated over a temperature range from 4 to 200 K. The transfer mechanism is dipole-dipole cross relaxation between the spins of the adsorbed mobile noble gas and the surface spins (spin-polarization-induced nuclear Overhauser effect). The enhancement of surface proton magnetization by laser-polarized helium at 4 K and 10 K is between one and twofold. Using laser-polarized xenon, enhancement factors of up to 20 were obtained when compared to the Boltzmann polarization in a field of 4.2 T and at a temperature of 130 K. C1 INST CHEM PHYS & BIOPHYS,EE-0026 TALLINN,ESTONIA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RI Room, Toomas/A-6412-2008; Appelt, Stephan/I-3168-2012; Appelt, Stefan/C-1541-2017 OI Room, Toomas/0000-0002-6165-8290; Appelt, Stefan/0000-0001-6036-2167 NR 34 TC 70 Z9 70 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11604 EP 11610 DI 10.1103/PhysRevB.55.11604 PG 7 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400096 ER PT J AU Staub, U Osborn, R Balcar, E Soderholm, L Trounov, V AF Staub, U Osborn, R Balcar, E Soderholm, L Trounov, V TI Wave-vector dependence of intermultiplet transitions in EuBa2Cu3Ox(x=6.1 and 7): An inelastic neutron-scattering study SO PHYSICAL REVIEW B LA English DT Article ID RARE-EARTH IONS; CRYSTAL-FIELD; MAGNETIC-PROPERTIES; 6-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-7; SPECTROSCOPY; EXCITATIONS; ERBA2CU3OX; PRBA2CU3O7; HOBA2CU3O7; ND3+ AB The momentum-transfer (Q) dependence of inelastic-neutron-scattering dipolar and higher multipolar CEF split transitions from EU3+ in EuBa2Cu3Ox (x=6.1 and 7) are calculated and, where possible, compared with the observations. For the transitions between the F-7(0) and the F-7(4) CEF split multiplets, distinct differences in the Q dependence between the different excitations is anticipated. Some of these transitions are expected to have relatively strong dipolar contributions. In order to perform these calculations, it was necessary to fit the transitions to a model crystal-field splitting scheme in order to determine the eigenfunctions and corresponding energy levels as input for the e-dependence calculations. We found an unusually low-energy separation between the F-7(0) ground state and the first excited F-7(1) multiplet which is well understood due to two effects. First, the strong CEF interaction mixes the wave functions of states between different multiplets which leads to a reduction of the energy separation. Second, the free-ion parameters are slightly reduced, which could be understood by assuming a linear behavior with the average distance of the nearest-neighbor shell. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV VIENNA,ATOMINST,A-1020 VIENNA,AUSTRIA. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. LENINGRAD NUCL PHYS INST,GATCHINA 188350,ST PETERSBURG,RUSSIA. 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 29 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11629 EP 11636 DI 10.1103/PhysRevB.55.11629 PG 8 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400099 ER PT J AU Freericks, JK Nicol, EJ Liu, AY Quong, AA AF Freericks, JK Nicol, EJ Liu, AY Quong, AA TI Vertex-corrected tunneling inversion in electron-phonon mediated superconductors: Pb SO PHYSICAL REVIEW B LA English DT Article ID NONADIABATIC SUPERCONDUCTIVITY; ATTRACTIVE HOLSTEIN; HUBBARD MODELS; MIGDALS THEOREM; DIMENSIONS AB The McMillan-Rowell tunneling inversion program, which extracts the electron-phonon spectral function alpha(2)F(Omega) and the Coulomb pseudopotential mu* from experimental tunneling data, is generalized to include the lowest-order vertex correction. We neglect the momentum dependence of the electron-phonon matrix elements, which is formally equivalent to using a local approximation. The perturbation theory is performed on the imaginary axis and then an exact analytic continuation is employed to produce the tunneling density of states on the real axis. Comparison is made with the experimental data for Pb. We find lambda is increased by approximately 1% due to the vertex corrections. C1 UNIV GUELPH,DEPT PHYS,GUELPH,ON N1G 2W1,CANADA. SANDIA NATL LABS,LIVERMORE,CA 94551. RP Freericks, JK (reprint author), GEORGETOWN UNIV,DEPT PHYS,WASHINGTON,DC 20057, USA. RI Freericks, James/D-7502-2011; Liu, Amy/E-2266-2015; OI Liu, Amy/0000-0002-2011-1854; Freericks, James/0000-0002-6232-9165 NR 31 TC 7 Z9 7 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11651 EP 11658 DI 10.1103/PhysRevB.55.11651 PG 8 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400102 ER PT J AU Sasik, R Bulaevskii, LN Bishop, AR Maley, MP AF Sasik, R Bulaevskii, LN Bishop, AR Maley, MP TI Vortices and plasmons in inductive periodic Josephson-junction arrays SO PHYSICAL REVIEW B LA English DT Article ID LAYERED SUPERCONDUCTORS; INDUCTANCES; MOTION; MODEL AB We derive a Hamiltonian for two- and three-dimensional inductive Josephson-junction arrays. The variables to describe the system are the gauge-invariant phase differences across the junctions. Therefore in this approach the phase of the superconducting order parameter and the magnetic vector potential are treated on equal footing, which makes it a useful tool to study phenomena in which fluctuations of both magnetic field and the superconducting order parameter are relevant. Among such applications is the study of thermodynamics of the mixed state of high-T-c superconductors at flux densities B much less than H-c2. We take into account screening by the superconducting currents in the electrodes forming the network and show that their effect in two-dimensional networks is only important at distances smaller than some characteristic length Lambda(e). In three-dimensional networks the magnetic interaction of currents is always short ranged regardless of the superconducting properties of the electrodes. We also derive time-dependent equations for the phase differences and a dispersion relation of a plasmon at zero temperature in the absence of vortices. RP Sasik, R (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 16 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11688 EP 11692 DI 10.1103/PhysRevB.55.11688 PG 5 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400105 ER PT J AU Nowak, ER Taylor, OW Liu, L Jaeger, HM Selinder, TI AF Nowak, ER Taylor, OW Liu, L Jaeger, HM Selinder, TI TI Magnetic flux instabilities in superconducting niobium rings: Tuning the avalanche behavior SO PHYSICAL REVIEW B LA English DT Article ID CRITICAL STATE; DYNAMICS; FILMS; STABILITY; LATTICES; GROWTH AB We study the dynamics of superconducting vortices in Nb rings as the system is continuously driven to the depinning threshold by the slow ramping of an external magnetic field. Miniature Hall probes simultaneously detect local and global flux changes arising from vortex motion. With decreasing temperature, the dynamics evolve continuously from smooth flow to several types of avalanche behavior. In particular, we observe a crossover from broad to narrow size distributions of avalanche events which correspond to global decreases in the flux density gradient rather than local redistributions of flux. We show how this evolution can arise from the magnetothermal instability of the Bean state. C1 UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Nowak, ER (reprint author), UNIV CHICAGO,JAMES FRANCK INST,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 28 TC 57 Z9 57 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11702 EP 11705 DI 10.1103/PhysRevB.55.11702 PG 4 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400107 ER PT J AU Vasumathi, D Barbiellini, B Manuel, AA Hoffmann, L Jarlborg, T Modler, R Geibel, C Steglich, F Peter, M AF Vasumathi, D Barbiellini, B Manuel, AA Hoffmann, L Jarlborg, T Modler, R Geibel, C Steglich, F Peter, M TI Fermi surface of CeCu2Si2 by 2D angular correlation of positron annihilation radiation SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; SUPERCONDUCTOR CECU2SI2; BAND-STRUCTURE; SYSTEMS; CERU2SI2; LIQUID; STATES; CEB6 AB We have carried out 2D angular correlation of positron annihilation radiation measurements on oriented single crystals of the heavy-fermion superconductor CeCu2Si2. Measurements have been made at 50 and 4 K which are above and below the Kondo temperature, T-K similar to 15 K, for this compound. The measurements show a small temperature dependence. Experimental results have been compared with linear muffin-tin orbital band-structure calculations for CeCu2Si2 and the isostructural non-f-electron compound, LaCu2Si2, The measured anisotropies agree well with the calculations. In addition, at both temperatures, the measured [001] projected k-space occupation densities reflect clearly the Fermi-surface breaks predicted by the calculations for CeCu2Si2. This implies that local-density approximation calculations provide a good description of the electronic structure in CeCu2Si2. We have also measured the positron lifetime in both superconducting (S-type) and magnetic (A-type) samples of CeCu2Si2. The lifetime and intensity components in the S- and A-type polycrystals are different, suggesting that the nature of the defects that trap positrons is different in the two phases. C1 HELSINKI UNIV TECHNOL, PHYS LAB, FIN-02150 ESPOO, FINLAND. LOS ALAMOS NATL LAB, DIV MAT SCI & TECHNOL, LOS ALAMOS, NM 87545 USA. TH DARMSTADT, INST FESTKORPERPHYS, D-64289 DARMSTADT, GERMANY. RP UNIV GENEVA, DEPT PHYS, 24 QUAI E ANSERMET, CH-1211 GENEVA 4, SWITZERLAND. RI Barbiellini, Bernardo/K-3619-2015 OI Barbiellini, Bernardo/0000-0002-3309-1362 NR 48 TC 19 Z9 19 U1 0 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11714 EP 11721 DI 10.1103/PhysRevB.55.11714 PG 8 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400109 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI Cases of resonant tunneling important for high-T-c cuprates SO PHYSICAL REVIEW B LA English DT Article ID SINGLE-CRYSTALS; TRANSPORT; AXIS AB Some basic assumptions made by the present author in his work about c-axis transport in layered cuprates are examined on simple models. First, a one-dimensional model is considered with a localized center slightly displaced from the middle df the barrier in order to find out whether this displacement prevents resonant tunneling. Second, a three-dimensional model is analyzed with two resonant centers in the median plane; the goal is to establish whether tunneling through such centers can be coherent. The results provide support for the basic assumptions. RP Abrikosov, AA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 10 TC 14 Z9 14 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11735 EP 11737 DI 10.1103/PhysRevB.55.11735 PG 3 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400112 ER PT J AU BussmannHolder, A Bishop, AR Genzel, L Simon, A AF BussmannHolder, A Bishop, AR Genzel, L Simon, A TI Doping dependence of T-c and its related isotope effect in high-temperature superconductors SO PHYSICAL REVIEW B LA English DT Article ID ANHARMONIC PHONONS; AXIS; PSEUDOGAP; YBA2CU3O7; PLANES AB A structure specific four-band model Hamiltonian is used to investigate the various doping dependences of the superconducting temperature T-c and the related isotope effect for YBa2Cu3O7 (YBCO). The model considers explicitly multiphonon-mediated attractive electron (hole) pairing Which acts intra- and interband and yields a complicated three-dimensional gap structure. The doping dependence of T-c is calculated by varying the band specific density of states, and from this the corresponding isotope effect is evaluated. Consistent agreement with experimental results is obtained and predictions with respect to site selective doping (including the isotope effect) are given. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP BussmannHolder, A (reprint author), MAX PLANCK INST FESTKORPERFORSCH,HEISENBERGSTR 1,D-70569 STUTTGART,GERMANY. NR 36 TC 12 Z9 12 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11751 EP 11755 DI 10.1103/PhysRevB.55.11751 PG 5 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400115 ER PT J AU Hou, LF Deak, J Metcalf, P McElfresh, M Preosti, G AF Hou, LF Deak, J Metcalf, P McElfresh, M Preosti, G TI Dependence of the vortex-solid phase transition of YBa2Cu3O7-delta thin films on anisotropy: Evidence for a universal phase boundary SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; LATTICE-MELTING TRANSITION; SINGLE-CRYSTALS; IRREVERSIBILITY LINE; TRANSPORT ANISOTROPY; THERMAL FLUCTUATIONS; OXYGEN STOICHIOMETRY; SQUID PICOVOLTOMETRY; GLASS-TRANSITION; MAGNETIC-FIELDS AB The vortex-solid phase boundary of YBa2Cu3O7-delta (YBCO) thin films was studied as a function of oxygen stoichiometry, delta, using magnetotransport measurements. Experimental evidence for a characteristic crossover field, H-0, separating two distinct types of behavior, was observed for films with delta>0.12 to occur at a temperature, T-0, that is about half of the superconducting transition temperature (T-0 approximate to T-c/2). When plotted as H-g(T)/H-0 versus (1-T/T-c), all of the boundaries collapse onto a single universal curve. An implication of this collapse is that an empirical equation which depends only on T-c, the anisotropy gamma, and T-0, H-g(T) = H-0[(1 - T/T-c)/(1 - T-0/T-c)](n), where H-0 = [1.2 phi(0)/(sy)(2)], can be used to describe the H-g(T) boundary for any YBCO thin film and other disordered YBCO materials. Estimates of the vortex-glass (VG) correlation length, xi(VG), are made. The value of xi(VG) at the point where VG scaling finally breaks down is found to be independent of magnetic field for the fully oxygenated films, however, it is dependent on field for deoxygenated films. This result suggests that the pinning in the fully oxygenated films is dominated by correlated disorder while pinning in the deoxygenated films becomes dominated by quenched disorder. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Hou, LF (reprint author), PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907, USA. NR 52 TC 35 Z9 35 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11806 EP 11815 DI 10.1103/PhysRevB.55.11806 PG 10 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400123 ER PT J AU McDonald, J Clem, JR Oates, DE AF McDonald, J Clem, JR Oates, DE TI Critical-state model for harmonic generation in a superconducting microwave resonator SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; IMPEDANCE; LOSSES; FIELD AB A critical-state model is developed for the treatment of the nonlinear ac response of a superconducting coaxial-type transmission line. Analytical results are presented for the resistance and reactance as well as the response at overtone frequencies. Center conductors of both elliptical and rectangular thin-film cross section are considered. The dominant response, in the case of the elliptical geometry, is found to be independent of the aspect ratio of the ellipse. Significant differences are found between the elliptical and strip geometries. These differences are due to the difference in-structure of the critical state in the two geometries. The model is applied to resonators with the assumption that end effects can be neglected. Qualitative agreement is found with experimental results. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. MIT,LINCOLN LAB,LEXINGTON,MA 02173. MIT,DEPT PHYS,CAMBRIDGE,MA 02139. RP McDonald, J (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 21 TC 26 Z9 26 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 17 BP 11823 EP 11831 DI 10.1103/PhysRevB.55.11823 PG 9 WC Physics, Condensed Matter SC Physics GA WY504 UT WOS:A1997WY50400125 ER PT J AU Lenosky, TJ Kress, JD Collins, LA Kwon, I AF Lenosky, TJ Kress, JD Collins, LA Kwon, I TI Molecular-dynamics modeling of shock-compressed liquid hydrogen SO PHYSICAL REVIEW B LA English DT Article ID SOLID HYDROGEN; METALLIC HYDROGEN; DENSE HYDROGEN; STATE; TRANSITIONS; EQUATION; PLASMA AB We have developed a tight-binding model of hydrogen with a single s orbital on each atom that reproduces properties of the dimer, of various crystalline structures, and of the fluid. Molecular-dynamics simulations, performed in the density and temperature regime of recent experiments on shock-compressed liquid hydrogen, give pressures and electrical conductivities in general agreement with the measured values. We also demonstrate a close connection between the conductivity and dissociation of the molecules in the fluid. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. NR 29 TC 51 Z9 51 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 11907 EP 11910 PG 4 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000001 ER PT J AU Matsuda, M Katsumata, K Kojima, KM Larkin, M Luke, GM Merrin, J Nachumi, B Uemura, YJ Eisaki, H Motoyama, N Uchida, S Shirane, G AF Matsuda, M Katsumata, K Kojima, KM Larkin, M Luke, GM Merrin, J Nachumi, B Uemura, YJ Eisaki, H Motoyama, N Uchida, S Shirane, G TI Magnetic phase transition in the S=1/2 zigzag-chain compound SrCuO2 SO PHYSICAL REVIEW B LA English DT Article ID COMPETING INTERACTIONS; SPIN RELAXATION; LADDERS; SUPERCONDUCTIVITY; FIELD; GAPS AB We have studied the magnetic properties of the S=1/2 quasi-one-dimensional Heisenberg antiferromagnet SrCuO2, which has zigzag chains of Cu2+ ions. We have observed a static magnetic ordering below T-c similar to 2 K. The weak internal field in the muon spin relaxation spectra and the absence of the magnetic Bragg peaks below T-c suggest that the Cu2+ moments are largely reduced probably due to the quantum fluctuation. The remarkable suppression of the ordering temperature (kT(c)/J(2)=1.1x10(-3)), where J(2) is the dominant exchange constant, probably originates from the combined effects of quantum fluctuation and frustration. C1 COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027. UNIV TOKYO,CTR SUPERCONDUCT RES,BUNKYO KU,TOKYO 113,JAPAN. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Matsuda, M (reprint author), INST PHYS & CHEM RES,2-1 HIROSAWA,WAKO,SAITAMA 35101,JAPAN. RI Luke, Graeme/A-9094-2010; Matsuda, Masaaki/A-6902-2016 OI Matsuda, Masaaki/0000-0003-2209-9526 NR 25 TC 53 Z9 53 U1 1 U2 15 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 11953 EP 11956 PG 4 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000013 ER PT J AU Argyriou, DN Mitchell, JF Potter, CD Bader, SD Kleb, R Jorgensen, JD AF Argyriou, DN Mitchell, JF Potter, CD Bader, SD Kleb, R Jorgensen, JD TI Unconventional magnetostriction in layered La1.2Sr1.8Mn2O7: Evidence for spin-lattice coupling above T-C SO PHYSICAL REVIEW B LA English DT Article AB The crystal structure of La1.2Sr1.8Mn2O7 has been determined as a function of temperature in magnetic fields of 0 and 0.6 T. There is a significant magnetostriction at the Curie temperature T-C; the a axis contracts (Delta a/a=-0.018%) while the c axis expands (Delta c/c=0.05%). The latter value is larger than that found for perovskite manganites (Delta l/l=0.02% at 1 T). No such effect occurs at lower temperatures. The magnetostriction results from changes in individual Mn-O bond lengths. From T-C to similar to 300 K, bulk magnetization and magnetoresistance measurements indicate the presence of magnetic order not observed in the neutron-diffraction data. This suggests short-range magnetic order in this temperature range. Our structural measurements show that within this temperature interval there is also a weak magnetostriction. C1 ARGONNE NATL LAB,DIV SCI MAT,ARGONNE,IL 60439. RP Argyriou, DN (reprint author), ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCTIV,ARGONNE,IL 60439, USA. RI Bader, Samuel/A-2995-2013 NR 11 TC 89 Z9 89 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 11965 EP 11968 PG 4 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000016 ER PT J AU Jimenez, I Jankowski, AF Terminello, LJ Sutherland, DGJ Carlisle, JA Doll, GL Tong, WM Shuh, DK Himpsel, FJ AF Jimenez, I Jankowski, AF Terminello, LJ Sutherland, DGJ Carlisle, JA Doll, GL Tong, WM Shuh, DK Himpsel, FJ TI Core-level photoabsorption study of defects and metastable bonding configurations in boron nitride SO PHYSICAL REVIEW B LA English DT Article ID THIN-FILMS; SYNCHROTRON-RADIATION; RAMAN-SPECTROSCOPY; POINT-DEFECTS; DEPOSITION; BN; CRYSTALS; DIAMOND; EXCITON; SOLIDS AB A comprehensive study of different local bonding environments in boron nitride bulk and thin films has been performed by core-level photoabsorption. Several features not present in crystalline reference samples are found in the absorption spectra of the thin films. These are identified as nitrogen vacancies in the hexagonal bonding of BN, nitrogen interstitials, boron clustering, sp(3)-like metastable phases, and sp(3) phases. Quantitative information on the concentration and distribution of point defects is easily extracted from the photoabsorption data and is discussed with regard to the formation of additional phases, the B:N ratio in the films, and compared with a random model of defect formation. Information on the stability of the bonding environments is gained by annealing the thin films. Modification of the orientation of the sp(2) hexagonal planes is attained by ion bombardment and annealing, and is monitored by angle-resolved photoabsorption. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. TIMKEN RES,MAT RES DEPT,CANTON,OH 44706. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. RI Jimenez, Ignacio/F-7422-2010; Tong, William/D-2564-2010 OI Jimenez, Ignacio/0000-0001-5605-3185; NR 40 TC 109 Z9 109 U1 3 U2 16 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 12025 EP 12037 DI 10.1103/PhysRevB.55.12025 PG 13 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000029 ER PT J AU Li, SP Eastman, JA Newnham, RE Cross, LE AF Li, SP Eastman, JA Newnham, RE Cross, LE TI Diffuse phase transition in ferroelectrics with mesoscopic heterogeneity: Mean-field theory SO PHYSICAL REVIEW B LA English DT Article ID BARIUM-TITANATE CERAMICS; LEAD SCANDIUM TANTALATE; DIELECTRIC-PROPERTIES; LANDAU THEORY; SOFT MODES; RELAXOR FERROELECTRICS; PEROVSKITE COMPOUNDS; ELECTRON-MICROSCOPY; SOLID-SOLUTION; PB(SC1/2TA1/2)O3 AB The diffuse phase transition in ferroelectrics with mesoscopic heterogeneity has been discussed within the context of a superparaelectric model by using the Ginzburg-Landau formalism. In the Curie region ferroelectries with mesoscopic heterogeneity are treated as ''superparaelectrics'' consisting of a mass of polar clusters, each of which has Ising character. Based on the mean-field theory, the influence of the finite-size effects of polar clusters on their structural instability has been discussed by considering a coherent lattice coupling between two structurally different regions. In particular, we have analytically derived the explicit solutions of the distribution of local polarizations. In turn, the processes of polar nanophase precipitation and coarsening have been also discussed in conjunction with the local chemical or structural inhomogeneity. Moreover, we have also analyzed the relationship between the local polarization distribution and the static dielectric susceptibility in ferroelectrics with the nanometric scale heterogeneity. The width of the Curie region is dependent upon the distribution of the sum of localized correlation length, which reflects the size distribution of heterogeneity. The presented analysis reveals that the diffuse phase transition is closely associated with the existence of nanometric polar clusters and their physical size distribution. Intriguingly, our theoretical results bear a very close resemblance to most experimental observations. C1 PENN STATE UNIV,MAT RES LAB,UNIVERSITY PK,PA 16802. RP Li, SP (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Eastman, Jeffrey/E-4380-2011; OI Eastman, Jeff/0000-0002-0847-4265 NR 96 TC 45 Z9 46 U1 1 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 12067 EP 12078 DI 10.1103/PhysRevB.55.12067 PG 12 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000033 ER PT J AU Cui, T Cheng, E Alder, BJ Whaley, KB AF Cui, T Cheng, E Alder, BJ Whaley, KB TI Rotational ordering in solid deuterium and hydrogen: A path integral Monte Carlo study SO PHYSICAL REVIEW B LA English DT Article ID PRESSURE MOLECULAR-DYNAMICS; X-RAY-DIFFRACTION; MEGABAR PRESSURES; PHASE-TRANSITIONS; METALLIC HYDROGEN; DENSE HYDROGEN; GROUND-STATE; H-2; SIMULATIONS; EQUATION AB The path-integral Monte Carlo method with a constant-pressure ensemble is used to study both translational and orientational transitions in the phase diagram of D-2 and H-2 up to megabar pressures. With an intermolecular interaction potential determined to agree with the experimental equation of state, a rotational order-disorder phase transition is observed. The phase line for this transition is in quantitative agreement with part of the phase diagram for both D-2 and H-2. No structural phase transition, and no transitions to the D-A and H-A phases (phase III) are observed. We attribute this in part to the limitations of simulation cell size. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. JILIN UNIV,NATL LAB SUPERHARD MAT,CHANGCHUN 130023,PEOPLES R CHINA. NR 66 TC 49 Z9 52 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 12253 EP 12266 DI 10.1103/PhysRevB.55.12253 PG 14 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000051 ER PT J AU Salkola, MI Balatsky, AV Schrieffer, JR AF Salkola, MI Balatsky, AV Schrieffer, JR TI Spectral properties of quasiparticle excitations induced by magnetic moments in superconductors SO PHYSICAL REVIEW B LA English DT Article ID IMPURITIES; LATTICE; STATES AB The consequences of localized, classical magnetic moments in superconductors are explored and their effect on the spectral properties of the intragap bound states is studied. Above a critical moment, a localized quasiparticle excitation in an s-wave superconductor is spontaneously created near a magnetic impurity, inducing a zero-temperature quantum transition. In this transition, the spin quantum number of the ground state changes from zero to 1/2, while the total charge remains the same. In contrast, the spin-unpolarized ground state of a d-wave superconductor is found to be stable for any value of the magnetic moment when the normal-state energy spectrum possesses particle-hole symmetry. The effect of impurity scattering on the quasiparticle states is interpreted in the spirit of relevant symmetries of the clean superconductor. The results obtained by the non-self-consistent (T matrix) and the self-consistent mean-field approximations are compared and qualitative agreement between the two schemes is found in the regime where the coherence length is longer than the Fermi length. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. FLORIDA STATE UNIV,NHMFL,TALLAHASSEE,FL 32310. FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32310. RP Salkola, MI (reprint author), STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305, USA. NR 25 TC 150 Z9 150 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1997 VL 55 IS 18 BP 12648 EP 12661 DI 10.1103/PhysRevB.55.12648 PG 14 WC Physics, Condensed Matter SC Physics GA XA260 UT WOS:A1997XA26000095 ER PT J AU Hirschfeld, PJ Quinlan, SM Scalapino, DJ AF Hirschfeld, PJ Quinlan, SM Scalapino, DJ TI c-axis infrared conductivity of a d(x2-y2)-wave superconductor with impurity and spin-fluctuation scattering SO PHYSICAL REVIEW B LA English DT Article ID D-WAVE SUPERCONDUCTORS; PENETRATION DEPTH; OPTICAL CONDUCTIVITY; NORMAL-STATE; PSEUDOGAP; MODEL AB Results of a calculation of the c-axis infrared conductivity sigma(c) for a d(x2-y2)-wave superconductor, including both elastic impurity and inelastic spin-fluctuation scattering are presented and compared with the ab-plane conductivity sigma(ab) in the same model. In this model, the interlayer c-axis coupling is taken to be weak and diffusive. While in clean systems, inelastic scattering leads to a peak at omega=4 Delta(o) in sigma(ab) for T Delta vertex and an N Delta-NN transition t matrix which are calculated from a phenomenological model for NN and pi d reactions. In a calculation where the initial pion scattering effects are neglected, the predicted peaks of the pion absorption cross sections for H-2 and He-3 lie too high in energy in relation to the data. The effect of the final-state three-nucleon interaction turns out to be too small for changing the magnitude and shifting the peak position of the total absorption cross section for He-3. We demonstrate that the adjustment of the peak position for the deuteron cross section by small modifications of the Delta parameters automatically leads to the correct peak position in He-3. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. JAGIELLONIAN UNIV,INST PHYS,PL-30059 KRAKOW,POLAND. RUHR UNIV BOCHUM,INST THEORET PHYS 2,D-44780 BOCHUM,GERMANY. RP Kamada, H (reprint author), PAUL SCHERRER INST,CH-5232 VILLIGEN,SWITZERLAND. NR 55 TC 7 Z9 7 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1997 VL 55 IS 5 BP 2563 EP 2570 DI 10.1103/PhysRevC.55.2563 PG 8 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000053 ER PT J AU Ahle, L Akiba, Y Beavis, D Beery, P Britt, HC Budick, B Chasman, C Chen, Z Chi, CY Chu, YY Cianciolo, V Cole, BA Costales, JB Crawford, HJ Cumming, JB Debbe, R Engelage, J Fung, SY Gonin, M Gushue, S Hamagaki, H Hayano, RS Hayashi, S Homma, S Kaneko, H Kang, J Kaufman, S Kehoe, WL Ledoux, RJ LeVine, MJ Miake, Y Morrison, DP Morse, RJ Moskowitz, B Nagamiya, S Namboodiri, MN Nayak, TK Olness, J Parsons, CG Remsberg, LP Roerich, D Rothschild, P Sakurai, H Sangster, TC Seto, R Shigaki, K Soltz, R Stankus, P Steadman, SG Stephans, GSF Sung, T Tanaka, Y Tannenbaum, MJ Thomas, J Tonse, S Ueno, S vanDijk, JH Videbaek, F Vossnack, O Vustadakis, V Wang, FQ Wang, Y Wegner, HE Woodruff, DS Wu, YD Yagi, K Yang, X Zachary, D Zajc, WA AF Ahle, L Akiba, Y Beavis, D Beery, P Britt, HC Budick, B Chasman, C Chen, Z Chi, CY Chu, YY Cianciolo, V Cole, BA Costales, JB Crawford, HJ Cumming, JB Debbe, R Engelage, J Fung, SY Gonin, M Gushue, S Hamagaki, H Hayano, RS Hayashi, S Homma, S Kaneko, H Kang, J Kaufman, S Kehoe, WL Ledoux, RJ LeVine, MJ Miake, Y Morrison, DP Morse, RJ Moskowitz, B Nagamiya, S Namboodiri, MN Nayak, TK Olness, J Parsons, CG Remsberg, LP Roerich, D Rothschild, P Sakurai, H Sangster, TC Seto, R Shigaki, K Soltz, R Stankus, P Steadman, SG Stephans, GSF Sung, T Tanaka, Y Tannenbaum, MJ Thomas, J Tonse, S Ueno, S vanDijk, JH Videbaek, F Vossnack, O Vustadakis, V Wang, FQ Wang, Y Wegner, HE Woodruff, DS Wu, YD Yagi, K Yang, X Zachary, D Zajc, WA TI Baryon emission at target rapidities in Si+Al,Cu,Au collisions at 14.6A GeV/c and Au+Au collisions at 11.7A GeV/c SO PHYSICAL REVIEW C LA English DT Article ID PARTICLE-PRODUCTION; SPECTROMETER; DETECTOR; DYNAMICS; PROTONS AB We report measurements of proton emission at target rapidities for minimum bias and central collisions of 14.6A GeV/c Si-28 With Al, Cu, and Au nuclei as well as minimum bias and central collisions of 11.7A GeV/c (197)AU with Au nuclei. Results for deuteron emission are also reported for the Si + Au reaction. The spectra span the laboratory angular range of 50 degrees less than or equal to theta less than or equal to 130 degrees and kinetic energy range of 40 MeV less than or equal to E-kin less than or equal to 225 MeV. Inverse slopes of proton spectra and proton dN/d eta values in the kinetic energy range 50 MeV less than or equal to E-kin less than or equal to 110 MeV are reported. The inverse slopes are 40-80 MeV for the various systems, generally increasing with increasing pseudorapidity. The dN/d eta values for A + A collisions within the restricted kinetic energy interval are compared to those for protons from p + Au in the literature. All pseudorapidity distributions have very similar shapes. The experimental results have been compared to the predictions of the nucleon-nucleon collision models ARC and RQMD. The predictions made by these two models for the distribution of protons at target rapidities are very similar to each other. However, there are significant differences between the model predictions and the experimental results in the details of the spectral slopes and the proton yields for different trigger conditions. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. BROOKHAVEN NATL LAB,UPTON,NY 11973. UNIV CALIF BERKELEY,SPACE SCI LAB,BERKELEY,CA 94720. UNIV CALIF RIVERSIDE,RIVERSIDE,CA 92507. COLUMBIA UNIV,NEW YORK,NY 10027. NEVIS LABS,IRVINGTON,NY 10533. UNIV TOKYO,INST NUCL STUDY,TOKYO 188,JAPAN. KYOTO UNIV,SAKYO KU,KYOTO 606,JAPAN. KYUSHU UNIV,FUKUOKA 812,JAPAN. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NYU,NEW YORK,NY 10003. UNIV TOKYO,DEPT PHYS,TOKYO 113,JAPAN. UNIV TSUKUBA,TSUKUBA,IBARAKI 305,JAPAN. YONSEI UNIV,SEOUL 120749,SOUTH KOREA. RP Ahle, L (reprint author), MIT,77 MASSACHUSETTS AVE,CAMBRIDGE,MA 02139, USA. RI seto, richard/G-8467-2011; Cumming, James/I-3358-2013; SAKURAI, HIROYOSHI/G-5085-2014; Hayano, Ryugo/F-7889-2012; HAMAGAKI, HIDEKI/G-4899-2014; OI Cumming, James/0000-0001-6930-0958; Hayano, Ryugo/0000-0002-1214-7806; Tannenbaum, Michael/0000-0002-8840-5314; Thomas, James/0000-0002-6256-4536 NR 22 TC 4 Z9 4 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 MAY PY 1997 VL 55 IS 5 BP 2604 EP 2614 DI 10.1103/PhysRevC.55.2604 PG 11 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000058 ER PT J AU Wong, CY AF Wong, CY TI Suppression of J/psi and psi' production in high-energy Pb on Pb collisions SO PHYSICAL REVIEW C LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; QUARK-GLUON PLASMA; HADRON; STATE AB The anomalous J/psi suppression in Pb-Pb collisions at 158A GeV observed recently by NA50 can be explained as due to the transition to a phase of strong J/psi absorption, which sets in when the local energy density exceeds about 3.4 GeV/fm(3). RP OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. NR 35 TC 29 Z9 29 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1997 VL 55 IS 5 BP 2621 EP 2624 DI 10.1103/PhysRevC.55.2621 PG 4 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000060 ER PT J AU Burden, CJ Qian, L Roberts, CD Tandy, PC Thomson, MJ AF Burden, CJ Qian, L Roberts, CD Tandy, PC Thomson, MJ TI Ground-state spectrum of light-quark mesons SO PHYSICAL REVIEW C LA English DT Article ID CHIRAL-SYMMETRY BREAKING; PROPAGATOR; EQUATIONS; MASSES; DYSON; QCD AB A confining, Goldstone theorem preserving, separable ansatz for the ladder kernel of the two-body Bethe-Salpeter equation is constructed from phenomenologically efficacious u, d, and s dressed-quark propagators. The simplicity of the approach is its merit. It provides a good description of the ground-state flavor-octet pseudoscalar, vector, and axial-vector meson spectrum facilitates an exploration of the relative importance of various components of the two-body Bethe-Salpeter amplitudes, showing that subleading Dirac components an quantitatively important in the flavor-octet pseudoscalar meson channels, and allows a scrutiny of the domain of applicability of ladder truncation studies. A color-antitriplet diquark spectrum is obtained. The shortcomings of separable Ansatze and the ladder kernel are highlighted. C1 KENT STATE UNIV,DEPT PHYS,NUCL RES CTR,KENT,OH 44242. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. UNIV MELBOURNE,SCH PHYS,PARKVILLE,VIC 3052,AUSTRALIA. RP Burden, CJ (reprint author), AUSTRALIAN NATL UNIV,RES SCH PHYS SCI & ENGN,DEPT THEORET PHYS,CANBERRA,ACT 0200,AUSTRALIA. RI Burden, Conrad/D-5556-2016; OI Burden, Conrad/0000-0003-0015-319X; Roberts, Craig/0000-0002-2937-1361 NR 33 TC 121 Z9 122 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 MAY PY 1997 VL 55 IS 5 BP 2649 EP 2664 DI 10.1103/PhysRevC.55.2649 PG 16 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000064 ER PT J AU Ping, JL Wang, F Goldman, T AF Ping, JL Wang, F Goldman, T TI Representation transformation of multiquark wave functions SO PHYSICAL REVIEW C LA English DT Article ID FRACTIONAL-PARENTAGE; STATES AB It is shown that the representation transformations of multiquark wave functions between different coupling schemes are just the Racah coefficients of the permutation group. The transformation coefficients between the flavor-spin (FS) and the color-spin (CS) schemes are obtained. As an example, the expansion of the physical bases in terms of symmetry bases in the CS scheme are given for the interesting cases Y/J=201,210,000. C1 NANJING UNIV,CTR THEORET PHYS,NANJING 210008,PEOPLES R CHINA. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Ping, JL (reprint author), NANJING NORMAL UNIV,DEPT PHYS,NANJING 210097,PEOPLES R CHINA. NR 9 TC 4 Z9 5 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 MAY PY 1997 VL 55 IS 5 BP 2726 EP 2729 DI 10.1103/PhysRevC.55.2726 PG 4 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000076 ER PT J AU Tannenbaum, MJ AF Tannenbaum, MJ TI Intermittency and correlations in 200 GeV/nucleon S+S and S+Au collisions - Comment SO PHYSICAL REVIEW C LA English DT Letter ID MULTIPLICITY DISTRIBUTIONS; 14.6A GEV/C AB The W80 Collaboration [Phys. Rev. C 50, 1048 (1994)] has presented an analysis of normalized factorial moments (NFM) of multiplicity distributions in central S-32+S and S-32+Au collisions at 200 GeV/nucleon. They claim to observe no intermittency signal, as characterized by a variation of the NFM with rapidity interval, beyond that produced by folding the FRITIOF event generator with a detailed model of their detector. In this Comment, it is pointed out that the difference in magnitude between the measured NFM and the detector simulation, which was not considered by WA80, also contains important information which can be used to extract the true NFM. In particular, F-2 is extracted and compared to other experiments. RP Tannenbaum, MJ (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. OI Tannenbaum, Michael/0000-0002-8840-5314 NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1997 VL 55 IS 5 BP 2736 EP 2738 DI 10.1103/PhysRevC.55.2736 PG 3 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000079 ER PT J AU Batchelder, JC Toth, KS Bingham, CR Brown, LT Conticchio, LF Davids, CN Seweryniak, D Wauters, J Wood, JL Zganjar, EF AF Batchelder, JC Toth, KS Bingham, CR Brown, LT Conticchio, LF Davids, CN Seweryniak, D Wauters, J Wood, JL Zganjar, EF TI alpha-decay properties of Po-190 and the identification of Po-191 SO PHYSICAL REVIEW C LA English DT Article ID ISOTOPES; HEAVY AB The cy-decay properties of Po-190 were investigated through the use of a fragment mass analyzer in conjunction with a double-sided Si strip detector. The isotope was produced via the Mo-96(Mo-96,2n) reaction, and its alpha-decay energy and T-1/2 were measured as 7529(10) keV and 2.4(-0.3)(+0.4) ms, respectively. The resulting reduced width is nearly identical to that of the Po-192.194 isotopes. This is believed to result from significant mixing between the ground state pi(2p) and the low-lying O(+)pi(4p-2h) intruder state in the Po parent. The result provides further evidence for shape coexistence in the light Po isotopes. In addition, Po-191 was unambiguously identified, and the Pb-186 alpha-decay branch was determined experimentally for the first time. C1 LOUISIANA STATE UNIV,BATON ROUGE,LA 70803. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV TENNESSEE,KNOXVILLE,TN 37996. ARGONNE NATL LAB,ARGONNE,IL 60439. VANDERBILT UNIV,NASHVILLE,TN 37235. UNIV MARYLAND,COLLEGE PK,MD 20742. GEORGIA INST TECHNOL,ATLANTA,GA 30332. RP Batchelder, JC (reprint author), OAK RIDGE ASSOCIATED UNIV,UNIRIB,OAK RIDGE,TN 37831, USA. NR 15 TC 13 Z9 13 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 MAY PY 1997 VL 55 IS 5 BP R2142 EP R2145 PG 4 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000004 ER PT J AU Esumi, S Chapman, S vanHecke, H Xu, N AF Esumi, S Chapman, S vanHecke, H Xu, N TI Transverse flow at ultrarelativistic energies SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION COLLISIONS; NUCLEAR COLLISIONS; HYDRODYNAMIC EVOLUTION; PBARP COLLISIONS; COLLECTIVE FLOW; MATTER; EXPANSION; DISTRIBUTIONS; FLUCTUATIONS; SYSTEMS AB Within the framework of a phenomenological hydrodynamical model, the relationship of the freeze-out temperature parameter T-f and the transverse flow velocity v perpendicular to is discussed. It is found that the experimental single-particle distributions are not very sensitive to the exact form of the assumed velocity profile, but that there is a definite anticorrelation between T-f and the average v perpendicular to. C1 HIROSHIMA UNIV,HIGASHIHIROSHIMA 724,JAPAN. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 37 TC 19 Z9 19 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 MAY PY 1997 VL 55 IS 5 BP R2163 EP R2166 PG 4 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000009 ER PT J AU Lane, GJ Fossan, DB Thorslund, I Vaska, P Allatt, RG Paul, ES Kaubler, L Schnare, H Hibbert, IM OBrien, N Wadsworth, R Andrejtscheff, W deGraaf, J Simpson, J Lee, IY Macchiavelli, AO Blumenthal, DJ Davids, CN Lister, CJ Seweryniak, D Afanasjev, AV Ragnarsson, I AF Lane, GJ Fossan, DB Thorslund, I Vaska, P Allatt, RG Paul, ES Kaubler, L Schnare, H Hibbert, IM OBrien, N Wadsworth, R Andrejtscheff, W deGraaf, J Simpson, J Lee, IY Macchiavelli, AO Blumenthal, DJ Davids, CN Lister, CJ Seweryniak, D Afanasjev, AV Ragnarsson, I TI Identification of excited states in doubly odd Sb-110: Smooth band termination SO PHYSICAL REVIEW C LA English DT Article ID FRAGMENT MASS ANALYZER; HIGH-SPIN STATES; ROTATIONAL BANDS; COLLECTIVITY; SN-110; TE-110 AB Excited states in Sb-110 have been identified for the first time in a series of gamma-spectroscopy experiments using both thin and backed targets, including neutron-fold and recoil-mass measurements to provide unambiguous channel identification. The three decoupled intruder bands observed in Sb-110 are based upon configurations involving 2p-2h excitations across the Z = 50 shell gap and show the features of smooth band termination. The yrast intruder band, which has been connected to the low-spin levels, is tentatively identified up to its predicted termination at I-pi = 45(+). Excellent agreement with configuration-dependent cranked Nilsson-Strutinsky calculations is obtained for the high-spin states near termination. C1 UNIV LIVERPOOL,OLIVER LODGE LAB,LIVERPOOL L69 3BX,MERSEYSIDE,ENGLAND. DRESDEN UNIV TECHNOL,INST KERN & TEILCHENPHYS,D-01062 DRESDEN,GERMANY. ROSSENDORF INC,FORSCHUNGSZENTRUM ROSSENDORF EV,INST KERN & HADRONENPHYS,D-01314 DRESDEN,GERMANY. UNIV YORK,DEPT PHYS,YORK YO1 5DD,N YORKSHIRE,ENGLAND. BULGARIAN ACAD SCI,INST NUCL RES & NUCL ENERGY,BG-1784 SOFIA,BULGARIA. UNIV TORONTO,DEPT PHYS,TORONTO,ON M5S 1A7,CANADA. CCLRC,DARESBURY LAB,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV MARYLAND,COLLEGE PK,MD 20742. LUND INST TECHNOL,DEPT MATH PHYS,S-22100 LUND,SWEDEN. LATVIAN ACAD SCI,NUCL RES CTR,LV-2169 RIGA,LATVIA. RP Lane, GJ (reprint author), SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794, USA. RI Lane, Gregory/A-7570-2011 OI Lane, Gregory/0000-0003-2244-182X NR 31 TC 23 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 MAY PY 1997 VL 55 IS 5 BP R2127 EP R2131 PG 5 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000001 ER PT J AU Moore, EF Lauritsen, T Janssens, RVF Khoo, TL Ackermann, D Ahmad, I Amro, H Blumenthal, D Carpenter, MP Fischer, SM Hackman, G Nisius, D Hannachi, F LopezMartens, A Korichi, A Asztalos, S Clark, RM Deleplanque, MA Diamond, RM Fallon, P Lee, IY Macchiavelli, AO Stephens, FS Becker, JA Bernstein, L Farris, LP Henry, EA AF Moore, EF Lauritsen, T Janssens, RVF Khoo, TL Ackermann, D Ahmad, I Amro, H Blumenthal, D Carpenter, MP Fischer, SM Hackman, G Nisius, D Hannachi, F LopezMartens, A Korichi, A Asztalos, S Clark, RM Deleplanque, MA Diamond, RM Fallon, P Lee, IY Macchiavelli, AO Stephens, FS Becker, JA Bernstein, L Farris, LP Henry, EA TI Differential lifetime measurements and identical superdeformed bands in Hg-192,Hg-194 SO PHYSICAL REVIEW C LA English DT Article ID SPIN STATES; HG-192; NUCLEI; REGION AB High-precision lifetime measurements have been performed in superdeformed (SD) bands of Hg-192,Hg-194 With the Doppler-shift attenuation method. Intrinsic quadrupole moments Q(0) were extracted for three SD bands in Hg-194 and for the yrast SD band in Hg-192. Within experimental uncertainties, all four SD bands have equal Q(0) values. These results provide constraints on differences in Q(0) values between the ''identical'' SD bands Hg-194(3) and Hg-192(1). C1 TRIANGLE UNIV NUCL LAB,DURHAM,NC 27708. ARGONNE NATL LAB,ARGONNE,IL 60439. CTR SPECTROMETRIE NUCL & SPECTROMETRIE MASSE,IN2P3,CNRS,F-91405 ORSAY,FRANCE. INST PHYS NUCL,F-91406 ORSAY,FRANCE. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Moore, EF (reprint author), N CAROLINA STATE UNIV,RALEIGH,NC 27695, USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 32 TC 47 Z9 47 U1 2 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1997 VL 55 IS 5 BP R2150 EP R2154 PG 5 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000006 ER PT J AU Seweryniak, D Davids, CN Walters, WB Woods, PJ Ahmad, I Amro, H Blumenthal, DJ Brown, LT Carpenter, MP Davinson, T Fischer, SM Henderson, DJ Janssens, RVF Khoo, TL Hibbert, I Irvine, RJ Lister, CJ MacKenzie, JA Nisius, D Parry, C Wadsworth, R AF Seweryniak, D Davids, CN Walters, WB Woods, PJ Ahmad, I Amro, H Blumenthal, DJ Brown, LT Carpenter, MP Davinson, T Fischer, SM Henderson, DJ Janssens, RVF Khoo, TL Hibbert, I Irvine, RJ Lister, CJ MacKenzie, JA Nisius, D Parry, C Wadsworth, R TI In-beam gamma-ray spectroscopy of the proton emitter Tm-147(69) using recoil-decay tagging SO PHYSICAL REVIEW C LA English DT Article ID RARE-EARTH NUCLEI; ISOTOPES; STATES AB Gamma rays from the decay of states in the proton unstable nucleus Tm-147 were observed for the first time following the Mo-92(Ni-58,p2n)Tm-147 reaction at 260 MeV. Prompt gamma rays were detected with an array of Compton-suppressed Ge detectors, placed in front of the fragment mass analyzer at the ATLAS accelerator, and were assigned to individual reaction channels on an event-by-event basis using the recoil-decay tagging method. Gamma-ray transitions were associated with both the proton decay of the pi h(11/2) ground state and the pi d(3/2) isomeric state in Tm-147, even though the cross sections for populating these states were only approximate to 16 mu b and 2 mu b, respectively. The level scheme which was constructed for Tm-147 is discussed and compared with the level structures for lighter N = 78 isotones. C1 UNIV MARYLAND,COLLEGE PK,MD 20742. UNIV EDINBURGH,EDINBURGH,MIDLOTHIAN,SCOTLAND. YORK UNIV,YORK,N YORKSHIRE,ENGLAND. RP Seweryniak, D (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Carpenter, Michael/E-4287-2015 OI Carpenter, Michael/0000-0002-3237-5734 NR 19 TC 27 Z9 27 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAY PY 1997 VL 55 IS 5 BP R2137 EP R2141 PG 5 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000003 ER PT J AU Souliotis, GA Loveland, W Zyromski, KE Wozniak, GJ Morrissey, DJ Liljenzin, JO Aleklett, K AF Souliotis, GA Loveland, W Zyromski, KE Wozniak, GJ Morrissey, DJ Liljenzin, JO Aleklett, K TI Production of neutron-rich nuclides and radioactive beams by intermediate energy U-238 fission SO PHYSICAL REVIEW C LA English DT Article ID CHARGE; SEPARATION; NUCLEI; IONS AB The yields of neutron-rich fission fragments from the interaction of 20 MeV/nucleon U-238 with (208)pb have been measured. The production mechanism of these fragments is consistent with sequential fission following a quasielastic or deep inelastic collision. Substantial yields of very n-rich fragments are observed. The importance of these data for generation of n-rich radioactive beams by fission of intermediate-energy projectiles is discussed. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MICHIGAN STATE UNIV,NATL SUPERCONDUCTING CYCLOTRON LAB,E LANSING,MI 48824. CHALMERS UNIV TECHNOL,DEPT NUCL CHEM,S-41296 GOTHENBURG,SWEDEN. UNIV UPPSALA,DEPT NEUTRON RES,NYKOPING,SWEDEN. RP Souliotis, GA (reprint author), OREGON STATE UNIV,DEPT CHEM,GILBERT HALL 153,CORVALLIS,OR 97331, USA. NR 21 TC 12 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 MAY PY 1997 VL 55 IS 5 BP R2146 EP R2149 PG 4 WC Physics, Nuclear SC Physics GA XB190 UT WOS:A1997XB19000005 ER PT J AU Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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 Efimov, A Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Brower, WS Masek, G Paar, HP Sivertz, M Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Casse, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Galik, RS Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Loner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, I Gladding, GE Gollin, CD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB McLean, KW Patel, PR Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, H ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MR AF Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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 Efimov, A Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Brower, WS Masek, G Paar, HP Sivertz, M Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Casse, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Galik, RS Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Loner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BI Ernst, I Gladding, GE Gollin, CD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Selen, M Thaler, JJ Edwards, KW Bellerive, A Janicek, R MacFarlane, DB McLean, KW Patel, PR Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, H ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoeller, MR TI Measurement of the direct photon spectrum in Y(1S) decays SO PHYSICAL REVIEW D LA English DT Article ID UPSILON(1S) DECAYS; PERTURBATIVE QCD; GLUONS AB Using data taken with the CLEO II detector at the Cornell Electron Storage Ring, we have determined the ratio of branching fractions: R-gamma=Gamma(Upsilon(1S)--> gamma gg)/Gamma(Upsilon(1S)-->ggg)=[2.75+/-0.04(stat)+/-0.15(syst)]%. From this ratio, we have determined the QCD scale parameter Lambda(<(MS)over bar>) (defined in the modified minimal subtraction scheme) to be Lambda(<(MS)over bar>)=233+/-11+/-59 MeV, from which we determine a value for the strong coupling constant alpha(s)(M-gamma(1S))=0.163+/-0.002+/-0.014, or alpha(s)(M-Z)=0.110+/-0.001+/-0.007. C1 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. WAYNE STATE UNIV, DETROIT, MI 48202 USA. CALTECH, PASADENA, CA 91125 USA. UNIV CALIF SAN DIEGO, LA JOLLA, CA 92093 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. 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. MCGILL UNIV, MONTREAL, PQ H3A 2T8, CANADA. UNIV TEXAS, AUSTIN, TX 78712 USA. BINP, RU-630090 NOVOSIBIRSK, RUSSIA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. UNIV CALIF SANTA BARBARA, SANTA BARBARA, CA 93106 USA. RP UNIV OKLAHOMA, NORMAN, OK 73019 USA. RI Schaffner, Stephen/D-1189-2011; Briere, Roy/N-7819-2014; Frasconi, Franco/K-1068-2016; OI Briere, Roy/0000-0001-5229-1039; Frasconi, Franco/0000-0003-4204-6587; Bean, Alice/0000-0001-5967-8674 NR 25 TC 34 Z9 34 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD MAY 1 PY 1997 VL 55 IS 9 BP 5273 EP 5281 DI 10.1103/PhysRevD.55.5273 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900003 ER PT J AU Kasahara, SM Allison, WWM Alner, GJ Ayers, DS Barrett, WL Bode, CR Border, PM Brooks, CB Cobb, JH Cockerill, DJA Cotton, RJ Courant, H DeMuth, DM Ewen, B Fields, TH Gallagher, HR Goodman, MC Gran, RW Gray, RN Johns, K Kafka, T Leeson, W Litchfield, PJ Longley, NP Lowe, MJ Mann, WA Marshak, ML May, EN Milburn, RH Miller, WH Mualem, L Napier, A Oliver, W Pearce, GF Peterson, EA Price, LE Roback, DM Ruddick, K Schmid, DJ Schneps, J Schub, MH Seidlein, RV Shupe, MA Sundaralingam, N Thron, JL Trost, HJ Uretsky, JL Vassiliev, V Villaume, G Wakely, SP Wall, D Werkema, SJ West, N AF Kasahara, SM Allison, WWM Alner, GJ Ayers, DS Barrett, WL Bode, CR Border, PM Brooks, CB Cobb, JH Cockerill, DJA Cotton, RJ Courant, H DeMuth, DM Ewen, B Fields, TH Gallagher, HR Goodman, MC Gran, RW Gray, RN Johns, K Kafka, T Leeson, W Litchfield, PJ Longley, NP Lowe, MJ Mann, WA Marshak, ML May, EN Milburn, RH Miller, WH Mualem, L Napier, A Oliver, W Pearce, GF Peterson, EA Price, LE Roback, DM Ruddick, K Schmid, DJ Schneps, J Schub, MH Seidlein, RV Shupe, MA Sundaralingam, N Thron, JL Trost, HJ Uretsky, JL Vassiliev, V Villaume, G Wakely, SP Wall, D Werkema, SJ West, N TI Study of cosmic ray composition in the knee region using multiple muon events in the Soudan 2 detector SO PHYSICAL REVIEW D LA English DT Article ID ENERGY-SPECTRA; CASCADES; NUCLEON; IRON; SIMULATION; ELEMENTS; TEV AB Deep underground muon events recorded by the Soudan 2 detector, located at a depth of 2100 m of water equivalent, have been used to infer the nuclear composition of cosmic rays in the ''knee'' region of the cosmic ray energy spectrum. The observed muon multiplicity distribution favors a composition model with a substantial proton content in the energy region 8 x 10(5) - 1.3 x 10(7) GeV/nucleus. C1 UNIV MINNESOTA, MINNEAPOLIS, MN 55455 USA. UNIV OXFORD, DEPT PHYS, OXFORD OX1 3RH, ENGLAND. RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. TUFTS UNIV, MEDFORD, MA 02155 USA. WESTERN WASHINGTON UNIV, BELLINGHAM, WA 98225 USA. RP ARGONNE NATL LAB, 9700 S CASS AVE, ARGONNE, IL 60439 USA. NR 45 TC 27 Z9 28 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 MAY 1 PY 1997 VL 55 IS 9 BP 5282 EP 5294 DI 10.1103/PhysRevD.55.5282 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900004 ER PT J AU Rizzo, TG AF Rizzo, TG TI Exploration of below threshold Z' mass and coupling determinations at the NLC SO PHYSICAL REVIEW D LA English DT Article ID E+E-COLLIDERS; ENERGY AB We examine of the capability of the Next Linear Collider to determine the mass as well as the couplings to leptons and b quarks of a new neutral gauge boson Z' below direct production threshold. By using simulated data collected at several different values of root s, we demonstrate how this can be done in a model-independent manner via an anonymous case approach. The importance of beam polarization to the success of this program is discussed. The procedure is shown to be easily extended to the case of top and charm quark couplings. RP Rizzo, TG (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 18 TC 17 Z9 17 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 MAY 1 PY 1997 VL 55 IS 9 BP 5483 EP 5493 DI 10.1103/PhysRevD.55.5483 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900024 ER PT J AU Poppitz, E Trivedi, SP AF Poppitz, E Trivedi, SP TI New models of gauge- and gravity-mediated supersymmetry breaking SO PHYSICAL REVIEW D LA English DT Article ID DUALITY; TECHNICOLOR AB We show that supersymmetry breaking in a class of theories with SU(N) x SU(N-2) gauge symmetry can be studied in a calculable a model. We use the a model to show that the supersymmetry-breaking vacuum in these theories leaves a large subgroup of flavor symmetries intact, and to calculate the masses of the low-lying states. By embedding the standard model gauge groups in the unbroken flavor symmetry group we construct a class of models in which supersymmetry breaking is communicated by both gravitational and gauge interactions. One distinguishing feature of these models is that the messenger fields, responsible for the gauge-mediated communication of supersymmetry breaking, are an integral part of the supersymmetry-breaking sector. We also show how, by lowering the scale that suppresses the nonrenormalizable operators, a class of purely gauge-mediated models with a combined supersymmetry-breaking-cum-messenger sector can be built. We briefly discuss the phenomenological features of the models we construct. C1 FERMILAB NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. RP UNIV CHICAGO, ENRICO FERMI INST, 5640 S ELLIS AVE, CHICAGO, IL 60637 USA. NR 54 TC 89 Z9 89 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 MAY 1 PY 1997 VL 55 IS 9 BP 5508 EP 5519 DI 10.1103/PhysRevD.55.5508 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900027 ER PT J AU Hinchliffe, I Paige, FE Shapiro, MD Soderqvist, J Yao, W AF Hinchliffe, I Paige, FE Shapiro, MD Soderqvist, J Yao, W TI Precision SUSY measurements at CERN LHC SO PHYSICAL REVIEW D LA English DT Article ID TOP-QUARK; P(P)OVER-BAR COLLISIONS; GRAND UNIFICATION; ROOT-S=1.8 TEV; SUPERGRAVITY; SUPERSYMMETRY; MODELS; SEARCH; BOSON AB If supersymmetry exists at the electroweak scale, then it should be discovered at the CERN Large Hadron Collider (LHC). Determining masses of supersymmetric particles, however, is more difficult. In this paper, methods are discussed to determine combinations of masses and of branching ratios precisely from experimentally observable distributions. In many cases such measurements alone can greatly constrain the particular supersymmetric model and determine its parameters with an accuracy of a few percent. Most of the results shown correspond to one year of running at LHC at ''low luminosity,'' 10(33) cm(-2)s(-1). C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. ROYAL INST TECHNOL,KTH,S-10044 STOCKHOLM,SWEDEN. RP Hinchliffe, I (reprint author), LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 27 TC 359 Z9 359 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 MAY 1 PY 1997 VL 55 IS 9 BP 5520 EP 5540 DI 10.1103/PhysRevD.55.5520 PG 21 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900028 ER PT J AU Hewett, JL Wells, JD AF Hewett, JL Wells, JD TI Searching for supersymmetry in rare B decays SO PHYSICAL REVIEW D LA English DT Article ID B->S-GAMMA DECAY; HIGGS SECTOR; 2-HIGGS-DOUBLET MODELS; FERMILAB-TEVATRON; QCD CORRECTIONS; STANDARD MODEL; CONSTRAINTS; BREAKING; B->SL+L; UNIFICATION AB We quantify the ability of B factories to observe supersymmetric contributions to the rare decays B-->X-s gamma and B -->X(s)l(+)l(-). A global fit to the Wilson coefficients which contribute to these decays is performed from Monte Carlo generated data on B(B --> X-s gamma and the kinematic distributions associated with the final state lepton pair in B --> X(s)l(+)l(-). This fit is then compared to supersymmetric predicitons. Evaluation of the Wilson coefficients is carried out with several different patterns of the superpartner spectrum. We find that B factories will be able to probe regions of the supersymmetry parameter space not accessible to CERN LEP Il, the Fermilab Tevatron, and perhaps the CERN LHC. We also employ the recent NLO calculation of the matrix elements for B --> X-S gamma and find the bound m(H)+/- > 300 GeV in two-Higgs-doublet models using present data. RP Hewett, JL (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 78 TC 168 Z9 168 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 MAY 1 PY 1997 VL 55 IS 9 BP 5549 EP 5560 DI 10.1103/PhysRevD.55.5549 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900030 ER PT J AU Ball, P Braun, VM AF Ball, P Braun, VM TI Use and misuse of QCD sum rules in heavy-to-light transitions: The decay B->rho e nu reexamined SO PHYSICAL REVIEW D LA English DT Article ID PION FORM-FACTOR; EXCLUSIVE SEMILEPTONIC DECAYS; QUARK EFFECTIVE THEORY; ISGUR-WISE FUNCTION; QUANTUM-CHROMODYNAMICS; RESONANCE PHYSICS; MESON DECAYS; ASYMPTOTIC-BEHAVIOR; WAVE-FUNCTIONS; B-MESONS AB The existing calculations of the form factors describing the decay B --> rho e nu from QCD sum rules have yielded conflicting results at small values of the invariant mass squared of the lepton pair. We demonstrate that the disagreement originates from the failure of the shea-distance expansion to describe the rho meson distribution amplitude in the region where almost the whole momentum is carried by one of the constituents. This limits the applicability of QCD sum rules based on the short-distance expansion of a three-point correlation function to heavy-to-light transitions and calls for an expansion around the light cone, as realized in the light-cone sum rule approach. We derive and update light-cone sum rules for all the semileptonic form factors, using recent results on the rho meson distribution amplitudes. The results are presented in detail together with a careful analysis of the uncertainties, including estimates of higher-twist effects, and compared to lattice calculations and recent CLEO measurements. We also derive a set of ''improved'' three-point sum rules, in which some of the problems of the short-distance expansion are avoided and whose results agree to good accuracy with those from light-cone sum rules. C1 NORDITA,DK-2100 COPENHAGEN,DENMARK. RP Ball, P (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 67 TC 103 Z9 104 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 MAY 1 PY 1997 VL 55 IS 9 BP 5561 EP 5576 DI 10.1103/PhysRevD.55.5561 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900031 ER PT J AU Brodsky, SJ Hoyer, P Magnea, L AF Brodsky, SJ Hoyer, P Magnea, L TI Rapidity gaps in perturbative QCD SO PHYSICAL REVIEW D LA English DT Article ID DEEP-INELASTIC-SCATTERING; DIFFRACTIVE SCATTERING; DISSOCIATION; MODEL AB We analyze diffractive deep inelastic scattering within perturbative QCD by studying lepton scattering on a heavy quark target. Simple explicit expressions are derived in impact parameter space for the photon wave function and the scattering cross sections corresponding to single and double Coulomb gluon exchange. At limited momentum transfers to the target, the results agree with the general features of the ''aligned jet model.'' The color-singlet exchange cross section receives a leading twist' contribution only from the aligned jet region, where the transverse size of the photon wave function remains finite in the Bjorken scaling limit. In contrast with inclusive DIS, in diffractive events there is no leading twist contribution to sigma(L)/sigma(T) from the lowest order () photon Fock state, and the cross section for heavy quarks is power suppressed in the quark mass. There are also important contributions with large momentum transfer to the target, which corresponds to events having high transverse momentum production in both the projectile and target rapidity regions, separated by a rapidity gap. C1 NORDITA,DK-2100 COPENHAGEN,DENMARK. RP Brodsky, SJ (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. OI Magnea, Lorenzo/0000-0002-7016-2756 NR 34 TC 16 Z9 16 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 MAY 1 PY 1997 VL 55 IS 9 BP 5585 EP 5597 DI 10.1103/PhysRevD.55.5585 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900034 ER PT J AU Brooks, TC Convery, ME Davis, WL DelSignore, KW Jenkins, TL Kangas, E Knepley, MG Kowalski, KL Taylor, CC Oh, SH Walker, WD Colestock, PL Hanna, B Martens, M Streets, J Ball, R Gustafson, HR Jones, LW Longo, MJ Bjorken, JD Abashian, A Morgan, N Pruneau, CA AF Brooks, TC Convery, ME Davis, WL DelSignore, KW Jenkins, TL Kangas, E Knepley, MG Kowalski, KL Taylor, CC Oh, SH Walker, WD Colestock, PL Hanna, B Martens, M Streets, J Ball, R Gustafson, HR Jones, LW Longo, MJ Bjorken, JD Abashian, A Morgan, N Pruneau, CA TI Analysis of charged-particle-photon correlations in hadronic multiparticle production SO PHYSICAL REVIEW D LA English DT Article ID HEAVY-ION COLLISIONS; HIGH-ENERGY; MULTIPLICITY DISTRIBUTIONS; EMULSION CHAMBERS; CENTAURO-TYPE; PHYSICS; MOMENTS; FIELD; QUARK; QCD AB In order to analyze data on joint charged-particle-photon distributions from an experimental search (T-864, MiniMax) for disoriented chiral condensate (DCC) at the Fermilab Tevatron collider, we have identified robust observables, ratios of normalized bivariate factorial moments, with many desirable properties. These include insensitivity to many efficiency corrections and the details of the modeling of the primary pion production, and sensitivity to the production of DCC, as opposed to the generic, binomial-distribution partition of pions into charged and neutral species. The relevant formalism is developed and tested in Monte Carlo simulations of the MiniMax experimental conditions. C1 DUKE UNIV, DEPT PHYS, DURHAM, NC 27708 USA. FERMILAB NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. UNIV MICHIGAN, DEPT PHYS, ANN ARBOR, MI 48109 USA. STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94305 USA. VIRGINIA POLYTECH INST & STATE UNIV, DEPT PHYS, BLACKSBURG, VA 24061 USA. WAYNE STATE UNIV, DEPT PHYS & ASTRON, DETROIT, MI 48202 USA. RP CASE WESTERN RESERVE UNIV, DEPT PHYS, CLEVELAND, OH 44106 USA. NR 53 TC 41 Z9 41 U1 1 U2 2 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 MAY 1 PY 1997 VL 55 IS 9 BP 5667 EP 5680 DI 10.1103/PhysRevD.55.5667 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900042 ER PT J AU Abe, F Akimoto, H Akopian, A Albrow, MG Amendolia, SR Amidei, D Antos, J Aota, S Apollinari, G Asakawa, T Ashmanskas, W Atac, M Azfar, F AzziBacchetta, P Bacchetta, N Badgett, W Bagdasarov, S Bailey, MW Bao, J deBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Barone, M Barzi, E Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bevensee, B Bhatti, A Biery, K Binkley, M Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bolla, G Bortoletto, D Boudreau, J Breccia, L Bromberg, C Bruner, N BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cauz, D Cen, Y Cervelli, F Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D CroninHennessy, D Culbertson, R Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Dunn, A Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Errede, D Errede, S Fan, Q Feild, G Ferretti, C Fiori, I Flaugher, B Fortney, L Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fukui, Y Funaki, S Galeotti, S Gallinaro, M Ganel, O GarciaSeiveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Groer, L GrossePilcher, C Guillian, G Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handler, R Hans, RM Happacher, F Hara, K Hardman, AD Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Hayashi, E Heinrich, J Hoffman, KD Hohlmann, M Holck, C Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Huston, J Huth, J Hylen, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y Jensen, H Joshi, U Kadel, RW Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Keeble, L Kelley, K Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kharadia, B Kim, BJ Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Korytov, A Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuwabara, T Kuhlmann, SE Kuns, E Laasanen, AT Lami, S Lammel, S Lamoureux, JL LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Long, O Loomis, C Loreti, M Lu, J Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Mitsushio, H Miyamoto, T Miyashita, S Moggi, N Morita, Y Mueller, J Mukherjee, A Muller, T Murat, P Nakada, H Nakano, I Nelson, C Neuberger, D NewmanHolmes, C Ngan, CY Ninomiya, M Nodulman, L Oh, SH Ohl, KE Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Oliveira, R Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Park, S Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, H Pitts, KT Plunkett, R Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Ribon, A Rimondi, F Ristori, L Robertson, WJ Rodrigo, T Rolli, S Romano, J Rosenson, L Roser, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Shapiro, MD Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Snider, FD Song, T Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, H Spiegel, L Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Strohmer, R Stuart, D Sullivan, G Soumarokov, A Sumorok, K Suzuki, J Takada, T Takahashi, T Takano, T Takikawa, K Tamura, N Tannenbaum, B Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W deTroconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Uemura, N Ukegawa, F Unal, G Valls, J vandenBrink, SC Vejcik, S Velev, G Vidal, R Vilar, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, J Wang, MJ Wang, QF Warburton, A Watts, T Webb, R Wei, C Wendt, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yu, L Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, W Zucchelli, S AF Abe, F Akimoto, H Akopian, A Albrow, MG Amendolia, SR Amidei, D Antos, J Aota, S Apollinari, G Asakawa, T Ashmanskas, W Atac, M Azfar, F AzziBacchetta, P Bacchetta, N Badgett, W Bagdasarov, S Bailey, MW Bao, J deBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Barone, M Barzi, E Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bevensee, B Bhatti, A Biery, K Binkley, M Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bolla, G Bortoletto, D Boudreau, J Breccia, L Bromberg, C Bruner, N BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cauz, D Cen, Y Cervelli, F Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D CroninHennessy, D Culbertson, R Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Dunn, A Eddy, N Einsweiler, K Elias, JE Ely, R Engels, E Errede, D Errede, S Fan, Q Feild, G Ferretti, C Fiori, I Flaugher, B Fortney, L Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fukui, Y Funaki, S Galeotti, S Gallinaro, M Ganel, O GarciaSeiveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Groer, L GrossePilcher, C Guillian, G Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handler, R Hans, RM Happacher, F Hara, K Hardman, AD Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Hayashi, E Heinrich, J Hoffman, KD Hohlmann, M Holck, C Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Huston, J Huth, J Hylen, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y Jensen, H Joshi, U Kadel, RW Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Keeble, L Kelley, K Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kharadia, B Kim, BJ Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Korytov, A Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuwabara, T Kuhlmann, SE Kuns, E Laasanen, AT Lami, S Lammel, S Lamoureux, JL LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Long, O Loomis, C Loreti, M Lu, J Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Mitsushio, H Miyamoto, T Miyashita, S Moggi, N Morita, Y Mueller, J Mukherjee, A Muller, T Murat, P Nakada, H Nakano, I Nelson, C Neuberger, D NewmanHolmes, C Ngan, CY Ninomiya, M Nodulman, L Oh, SH Ohl, KE Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Oliveira, R Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Park, S Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, H Pitts, KT Plunkett, R Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Ribon, A Rimondi, F Ristori, L Robertson, WJ Rodrigo, T Rolli, S Romano, J Rosenson, L Roser, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Shapiro, MD Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Snider, FD Song, T Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, H Spiegel, L Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Strohmer, R Stuart, D Sullivan, G Soumarokov, A Sumorok, K Suzuki, J Takada, T Takahashi, T Takano, T Takikawa, K Tamura, N Tannenbaum, B Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A Toyoda, H Trischuk, W deTroconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Uemura, N Ukegawa, F Unal, G Valls, J vandenBrink, SC Vejcik, S Velev, G Vidal, R Vilar, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, J Wang, MJ Wang, QF Warburton, A Watts, T Webb, R Wei, C Wendt, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yu, L Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, W Zucchelli, S TI Search for new particles decaying to dijets at CDF SO PHYSICAL REVIEW D LA English DT Article ID P(P)OVER-BAR COLLISIONS; HADRON COLLIDERS; ROOT-S=1.8 TEV; EXCITED QUARKS; BOSONS; TECHNICOLOR; DETECTOR AB We have used 106 pb(-1) of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at the 95% confidence level models containing the following new particles: axigluons and flavor universal colorons with a mass between 200 and 980 GeV/c(2), excited quarks with a mass between 80 and 570 GeV/c(2) and between 580 and 760 GeV/c(2), color octet techni-rho's with a mass between 260 and 480 GeV/c(2), W' bosons with a mass between 300 and 420 GeV/c(2), and E-6 diquarks with a mass between 290 and 420 GeV/c(2). C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV BOLOGNA,IST NAZL FIS NUCL,I-40127 BOLOGNA,ITALY. BRANDEIS UNIV,WALTHAM,MA 02266. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CHICAGO,CHICAGO,IL 60638. DUKE UNIV,DURHAM,NC 28708. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV FLORIDA,GAINESVILLE,FL 33611. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. UNIV GENEVA,CH-1211 GENEVA 4,SWITZERLAND. HARVARD UNIV,CAMBRIDGE,MA 02138. HIROSHIMA UNIV,HIGASHIHIROSHIMA 724,JAPAN. UNIV ILLINOIS,URBANA,IL 61801. MCGILL UNIV,INST PARTICLE PHYS,MONTREAL,PQ H3A 2T8,CANADA. UNIV TORONTO,TORONTO,ON M5S 1A7,CANADA. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. ERNEST ORLANDO LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. UNIV NEW MEXICO,ALBUQUERQUE,NM 87132. OHIO STATE UNIV,COLUMBUS,OH 43320. OSAKA CITY UNIV,OSAKA 588,JAPAN. UNIV PADUA,IST NAZL FIS NUCL,I-36132 PADUA,ITALY. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. UNIV PITTSBURGH,PITTSBURGH,PA 15270. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14628. ROCKEFELLER UNIV,NEW YORK,NY 10021. RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. ACAD SINICA,TAIPEI 11530,TAIWAN. TEXAS A&M UNIV,COLLEGE STN,TX 77843. TEXAS TECH UNIV,LUBBOCK,TX 79409. UNIV TSUKUBA,TSUKUBA,IBARAKI 315,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53806. YALE UNIV,NEW HAVEN,CT 06511. RP Abe, F (reprint author), KEK NAT LAB HIGH ENERGY PHYS,TSUKUBA,IBARAKI 315,JAPAN. RI Vucinic, Dejan/C-2406-2008; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Warburton, Andreas/N-8028-2013; Kim, Soo-Bong/B-7061-2014; Introzzi, Gianluca/K-2497-2015; OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Warburton, Andreas/0000-0002-2298-7315; Introzzi, Gianluca/0000-0002-1314-2580; Paulini, Manfred/0000-0002-6714-5787; CHANG, PAO-TI/0000-0003-4064-388X NR 26 TC 114 Z9 114 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAY 1 PY 1997 VL 55 IS 9 BP R5263 EP R5268 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX519 UT WOS:A1997WX51900001 ER PT J AU Benkadda, S Kassibrakis, S White, RB Zaslavsky, GM AF Benkadda, S Kassibrakis, S White, RB Zaslavsky, GM TI Self-similarity and transport in the standard map SO PHYSICAL REVIEW E LA English DT Article ID LONG-TIME CORRELATIONS; CHIRIKOV-TAYLOR MODEL; AREA-PRESERVING MAPS; ANOMALOUS DIFFUSION; ACCELERATOR MODES; CHAOS; SYSTEMS AB Anomalous transport is investigated for the standard map. A chain of exact self-similar islands in the vicinity of the period 5 accelerator island is found for a particular value of the map parameter. The transport is found to be superdiffusive with an anomalous exponent related to the characteristic temporal and spatial scaling parameters of the island chain. The value of the transport exponent is compared to the theory. The escape time distribution and Poincare recurrence distribution are found to have powerlike tails and the corresponding exponents are obtained and compared to the theory. C1 NYU, COURANT INST MATH SCI, NEW YORK, NY 10012 USA. NYU, DEPT PHYS, NEW YORK, NY 10003 USA. UNIV AIX MARSEILLE 1, EQUIPE TURBULENCE PLASMA, CNRS URA 773, INST MEDITERRANEEN TECHNOL, F-13451 MARSEILLE 20, FRANCE. RP PRINCETON UNIV, PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. RI White, Roscoe/D-1773-2013 OI White, Roscoe/0000-0002-4239-2685 NR 34 TC 67 Z9 67 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1997 VL 55 IS 5 BP 4909 EP 4917 DI 10.1103/PhysRevE.55.4909 PN A PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB191 UT WOS:A1997XB19100018 ER PT J AU Castillo, VM Hoover, WG Hoover, CG AF Castillo, VM Hoover, WG Hoover, CG TI Coexisting attractors in compressible Rayleigh-Benard flow SO PHYSICAL REVIEW E LA English DT Article ID MOLECULAR-DYNAMICS; CONVECTION; HYDRODYNAMICS AB We demonstrate that precise solutions of the convective flow equations for a compressible conducting viscous fluid can give degenerate stationary states. That is, two or more completely different stable flows can result for fixed stationary boundary conditions. We characterize these complex flows with finite-difference, smooth-particle methods, and high-order implicit methods. The fluids treated here are viscous conducting gases, enclosed by thermal boundaries in a gravitational field-the ''Rayleigh-Benard problem.'' Degenerate solutions occur in both two- and three-dimensional simulations. This coexistence of solutions is a macroscopic manifestation of the strange attractors seen in atomistic systems far from equilibrium. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Castillo, VM (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,LIVERMORE,CA 94551, USA. NR 12 TC 10 Z9 10 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1997 VL 55 IS 5 BP 5546 EP 5550 DI 10.1103/PhysRevE.55.5546 PN A PG 5 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB191 UT WOS:A1997XB19100085 ER PT J AU Stupakov, GV Breizman, BN Pekker, MS AF Stupakov, GV Breizman, BN Pekker, MS TI Nonlinear dynamics of microwave instability in accelerators SO PHYSICAL REVIEW E LA English DT Article AB We develop a nonlinear theory of the weak single bunch instability in electron and positron circular at accelerators and damping rings. a nonlinear equation is derived that governs the evolution of the amplitude of unstable oscillations with account of quantum diffusion effects due to the synchrotron radiation. Numerical solutions to this equation show a large variety of nonlinear regimes depending on the growth rate of the instability and the diffusion coefficient. Comparison with the observation in the Stanford Linear Collider Damping Ring at the Stanford Linear Accelerator Center shows qualitative agreement with the patterns observed in the experiment. C1 UNIV TEXAS,INST FUS STUDIES,AUSTIN,TX 78712. BUDKER INST NUCL PHYS,NOVOSIBIRSK 630090,RUSSIA. RP Stupakov, GV (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,POB 4349,STANFORD,CA 94309, USA. NR 17 TC 19 Z9 19 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1997 VL 55 IS 5 BP 5976 EP 5984 DI 10.1103/PhysRevE.55.5976 PN B PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200036 ER PT J AU Lee, SY Ng, KY AF Lee, SY Ng, KY TI Particle dynamics in storage rings with barrier rf systems SO PHYSICAL REVIEW E LA English DT Article ID SYNCHROTRON MOTION; VOLTAGE MODULATION; RESONANCE ISLANDS AB The stability of particle motion in a barrier rf system is studied. Parametric resonance strength functions for the barrier rf system with rf phase and voltage modulations are derived. We find that higher order parametric resonances of the barrier rf system are important. Tolerance of the rf phase modulational errors in the barrier rf system in the Fermilab Recycler, a cooling storage ring to recycle unused antiprotons from the Tevatron and to store newly produced cooled antiprotons, is analyzed. A constraint on the rate of bunch compression utilizing the barrier rf system is derived. C1 INDIANA UNIV,DEPT PHYS,BLOOMINGTON,IN 47405. RP Lee, SY (reprint author), FERMILAB NATL ACCELERATOR LAB,DEPT ACCELERATOR PHYS,BATAVIA,IL 60510, USA. NR 17 TC 13 Z9 13 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1997 VL 55 IS 5 BP 5992 EP 6001 DI 10.1103/PhysRevE.55.5992 PN B PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200038 ER PT J AU Rasmussen, KO Cai, D Bishop, AR GronbechJensen, N AF Rasmussen, KO Cai, D Bishop, AR GronbechJensen, N TI Dynamics of nonlinear localized states on finite discrete chains SO PHYSICAL REVIEW E LA English DT Article ID SCHRODINGER-EQUATIONS AB We present an analysis of boundary effects on soliton motion in one-dimensional discrete nonlinear Schrodinger systems. In an effective point particle framework, we derive effective potentials induced, respectively, by fixed and free boundaries for the integrable case. We establish an effective Hamiltonian that captures the soliton dynamics under the combined effects of the finiteness of the lattice size and the discreteness of nonintegrable systems. Our direct numerical simulations demonstrate that these potentials can describe the soliton motion excellently. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. TECH UNIV DENMARK,INST MATH MODELLING,DK-2800 LYNGBY,DENMARK. RP Rasmussen, KO (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Rasmussen, Kim/B-5464-2009 OI Rasmussen, Kim/0000-0002-4029-4723 NR 9 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 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1997 VL 55 IS 5 BP 6151 EP 6154 DI 10.1103/PhysRevE.55.6151 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200054 ER PT J AU Murillo, MS Kilcrease, DP Collins, LA AF Murillo, MS Kilcrease, DP Collins, LA TI Dense plasma microfield nonuniformity SO PHYSICAL REVIEW E LA English DT Article ID DISTRIBUTIONS; LINES AB Plasma microfield-constrained-average quantities arise in a variety of applications including the ion quadrupole effect, the ion motion problem, and autoionizing processes. We critically compare several methods for computing such quantities in the context of microfield-constrained field gradients, which are used for describing the ion quadrupole effect, a source of spectral line asymmetry. Specifically, we show that one adjustable parameter exponential approximation (APEX)-like theory is divergent and compare existing nearest-neighbor models, APEX, and Monte Carlo results. Moreover, we have performed molecular-dynamics simulations to assess the accuracy of these previous results. Our results indicate that APEX calculations of this particular constrained average are quite accurate except at large field values, which are unimportant for Line shapes. Interestingly, nearest-neighbor results are quite accurate for certain field gradients and not for others. RP Murillo, MS (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. OI Kilcrease, David/0000-0002-2319-5934 NR 15 TC 12 Z9 12 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 MAY PY 1997 VL 55 IS 5 BP 6289 EP 6292 DI 10.1103/PhysRevE.55.6289 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200078 ER PT J AU Wan, AS Barbee, TW Cauble, R Celliers, P DaSilva, LB Moreno, JC Rambo, PW Stone, GF Trebes, JE Weber, F AF Wan, AS Barbee, TW Cauble, R Celliers, P DaSilva, LB Moreno, JC Rambo, PW Stone, GF Trebes, JE Weber, F TI Electron density measurement of a colliding plasma using soft-x-ray laser interferometry SO PHYSICAL REVIEW E LA English DT Article ID INTERPENETRATION; COLLISION; IGNITION AB We have used a soft-x-ray laser interferometer to study the collision and subsequent interaction of counterstreaming high-density plasmas. The measured density profiles show the evolution of the colliding plasmas from interpenetration, when the low-density edge of the plasmas first collide, to stagnation at the symmetry plane with density building at the symmetry plane. We compare the measured profiles with density profiles calculated by the radiation hydrodynamic code LASNEX, which predicts plasma stagnation as soon as the plasmas collide, and a particle-in-cell code, which allows for interpenetration, softening the stagnation. RP Wan, AS (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 21 TC 47 Z9 51 U1 1 U2 7 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 MAY PY 1997 VL 55 IS 5 BP 6293 EP 6296 DI 10.1103/PhysRevE.55.6293 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200079 ER PT J AU Shvets, G Fisch, NJ AF Shvets, G Fisch, NJ TI Beam-channeled laser-wakefield accelerator SO PHYSICAL REVIEW E LA English DT Article ID ELECTRON-HOSE INSTABILITY; WAKE-FIELD ACCELERATION; PLASMA; PULSES; PROPAGATION AB A hybrid of laser-wakefield and plasma-wakefield accelerators is proposed, in which an intense laser pulse is optically guided by a plasma channel created by the leading portion of a high-current, low-energy electron beam. This accelerator configuration,appears to combine advantageously features of both laser-wakefield and plasma-wakefield accelerators. RP Shvets, G (reprint author), PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. NR 31 TC 5 Z9 5 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1997 VL 55 IS 5 BP 6297 EP 6300 DI 10.1103/PhysRevE.55.6297 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB192 UT WOS:A1997XB19200080 ER PT J AU Carlsten, BE AF Carlsten, BE TI Centrifugal space-charge force of an electron beam in a focusing element SO PHYSICAL REVIEW E LA English DT Article AB The centrifugal space-charge force of a continuous electron beam, focused in a lens of an accelerator, is numerically calculated. As in the case of an electron beam in a dipole magnetic field, the effect on the transverse motion of the particles from the centrifugal space-charge force in a focusing element tends to cancel the effect from the potential depression of the beam; however, the cancellation is not exact, as it is for the dipole case. The centrifugal space-charge force in the focusing case arises from a nonzero axial derivative of the transverse vector potential due to the beam's space charge, as the beam is transversely accelerated in the focusing element. The transverse equation of motion for particles in the beam is used to quantify the partial cancellation of the nonlinear transverse acceleration from the centrifugal space-charge force and from the beam's potential depression, for focusing both with a magnetic quadrupole lens and a solenoid. RP Carlsten, BE (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 7 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 MAY PY 1997 VL 55 IS 5 BP R4893 EP R4896 PN A PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA XB191 UT WOS:A1997XB19100014 ER PT J AU Bigio, IJ Mourant, JR AF Bigio, IJ Mourant, JR TI Ultraviolet and visible spectroscopies for tissue diagnostics: Fluorescence spectroscopy and elastic-scattering spectroscopy SO PHYSICS IN MEDICINE AND BIOLOGY LA English DT Article ID LASER-INDUCED FLUORESCENCE; SKIN PIGMENTED LESIONS; REFLECTANCE SPECTROPHOTOMETRY; ATHEROSCLEROTIC PLAQUE; NATIVE FLUORESCENCE; VIVO; INVIVO; INSITU; CANCER; NADH AB We review the application of fluorescence spectroscopy and elastic-scattering spectroscopy, over the ultraviolet-to-visible wavelength range, to minimally invasive medical diagnostics. The promises and hopes, as well as the difficulties, of these developing techniques are discussed. RP Bigio, IJ (reprint author), LOS ALAMOS NATL LAB,POB 1663,MS-E535,LOS ALAMOS,NM 87545, USA. OI Bigio, Irving/0000-0003-4168-1466 NR 80 TC 252 Z9 253 U1 5 U2 18 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0031-9155 J9 PHYS MED BIOL JI Phys. Med. Biol. PD MAY PY 1997 VL 42 IS 5 BP 803 EP 814 DI 10.1088/0031-9155/42/5/005 PG 12 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA WZ953 UT WOS:A1997WZ95300005 PM 9172260 ER PT J AU vanGemert, MJC Nelson, JS Milner, TE Smithies, DJ Verkruysse, W deBoer, JF Lucassen, GW Goodman, DM Tanenbaum, BS Norvang, LT Svaasand, LO AF vanGemert, MJC Nelson, JS Milner, TE Smithies, DJ Verkruysse, W deBoer, JF Lucassen, GW Goodman, DM Tanenbaum, BS Norvang, LT Svaasand, LO TI Non-invasive determination of port wine stain anatomy and physiology for optimal laser treatment strategies SO PHYSICS IN MEDICINE AND BIOLOGY LA English DT Article ID BIOLOGICAL TISSUES; IRRADIATION; LIGHT; SKIN AB The treatment of port wine stains (PWSs) using a flashlamp-pumped pulsed dye laser is often performed using virtually identical irradiation parameters. Although encouraging clinical results have been reported, we propose that lasers will only reach their full potential provided treatment parameters match individual PWS anatomy and physiology. The purpose of this paper is to review the progress made on the technical development and clinical implementation of (i) infrared tomography (IRT), optical reflectance spectroscopy (ORS) and optical low-coherence reflectometry (OLCR) to obtain in vivo diagnostic data on individual PWS anatomy and physiology and (ii) models of light and heat propagation, predicting irreversible vascular injury in human skin, to select optimal laser wavelength, pulse duration, spot size and radiant exposure for complete PWS blanching in the fewest possible treatment sessions. Although non-invasive optical sensing techniques may provide significant diagnostic data, development of a realistic model will require a better understanding of relevant mechanisms for irreversible vascular injury. C1 UNIV CALIF IRVINE,BECKMAN LASER INST & MED CLIN,IRVINE,CA 92715. UNIV AMSTERDAM,ACAD MED CTR,CTR LASER,NL-1105 AZ AMSTERDAM,NETHERLANDS. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. HARVEY MUDD COLL ENGN,CLAREMONT,CA. UNIV TRONDHEIM,NORWEGIAN INST TECHNOL,DIV PHYS ELECT,N-7034 TRONDHEIM,NORWAY. RI de Boer, Johannes/B-7590-2012; OI de Boer, Johannes/0000-0003-1253-4950; verkruysse, wim/0000-0002-1381-2740 FU NCRR NIH HHS [R03-RR06988]; NIAMS NIH HHS [1R01-AR42437-01A1, 1R29-AR41638-01A1] NR 32 TC 38 Z9 38 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0031-9155 J9 PHYS MED BIOL JI Phys. Med. Biol. PD MAY PY 1997 VL 42 IS 5 BP 937 EP 950 PG 14 WC Engineering, Biomedical; Radiology, Nuclear Medicine & Medical Imaging SC Engineering; Radiology, Nuclear Medicine & Medical Imaging GA WZ953 UT WOS:A1997WZ95300013 PM 9172268 ER PT J AU Artuso, M Efimov, A Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, D Bliss, DW Brower, WS Masek, G Paar, HP Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD GAidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R 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 Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, J Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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 AF Artuso, M Efimov, A Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, D Bliss, DW Brower, WS Masek, G Paar, HP Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD GAidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F 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 McLean, KW Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R 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 Skubic, P Wood, M Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, J Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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 TI Study of the B-0 semileptonic decay spectrum at the Y(4S) resonance SO PHYSICS LETTERS B LA English DT Article ID BRANCHING FRACTIONS AB We have made a first measurement of the lepton momentum spectrum in a sample of events enriched in neutral B's through a partial reconstruction of B-0 --> D*(-)l(+)<(nu)over bar>. This spectrum, measured with 2.38 fb(-1) of data collected at the Y(4S) resonance by the CLEO II detector, is compared directly to the inclusive lepton spectrum from all Y(4S) events in the same data set. These two spectra are consistent with having the same shape above 1.5 GeV/c. From the two spectra and two other CLEO measurements, we obtain the B-0 and B+ semileptonic branching fractions, b(0) and b(+), their ratio, and the production ratio f(+-)/f(00) of B+ and B-0 pairs at the Y(4S). We report b(+)/b(0) = 0.950(-0.080) (+0.117) +/- 0.091, b(0) = (10.78 +/- 0.60 +/- 0.69)%, and b(+) = (10.25 +/- 0.57 +/- 0.65)%. b(+)/b(0) is equivalent to the ratio of charged to neutral B lifetimes, tau(+)/tau(0). (C) 1997 Published by Elsevier Science B.V. C1 VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. WAYNE STATE UNIV,DETROIT,MI 48202. CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. INST PARTICLE PHYS,MONTREAL,PQ,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. BINP,RU-630090 NOVOSIBIRSK,RUSSIA. UNIV TEXAS,AUSTIN,TX 78712. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Artuso, M (reprint author), SYRACUSE UNIV,SYRACUSE,NY 13244, USA. RI Schaffner, Stephen/D-1189-2011; Briere, Roy/N-7819-2014; Frasconi, Franco/K-1068-2016 OI Briere, Roy/0000-0001-5229-1039; Frasconi, Franco/0000-0003-4204-6587 NR 15 TC 6 Z9 6 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 1 PY 1997 VL 399 IS 3-4 BP 321 EP 328 DI 10.1016/S0370-2693(97)00336-5 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WX037 UT WOS:A1997WX03700021 ER PT J AU Cao, NZ Chen, SY AF Cao, NZ Chen, SY TI An intermittency model for passive-scalar turbulence SO PHYSICS OF FLUIDS LA English DT Article ID FULLY-DEVELOPED TURBULENCE; REFINED SIMILARITY HYPOTHESES AB A phenomenological model for the inertial range scaling of passive-scalar turbulence is developed based on a bivariate log-Poisson model. An analytical formula of the scaling exponent for three-dimensional passive-scalar turbulence is deduced. The predicted scaling exponents are compared with experimental measurements, showing good agreement. (C) 1997 American Institute of Physics. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Cao, NZ (reprint author), IBM CORP,DIV RES,THOMAS J WATSON RES CTR,POB 218,YORKTOWN HTS,NY 10598, USA. RI Chen, Shiyi/A-3234-2010 NR 24 TC 16 Z9 19 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 1997 VL 9 IS 5 BP 1203 EP 1205 DI 10.1063/1.869265 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA WW801 UT WOS:A1997WW80100001 ER PT J AU Cook, AW AF Cook, AW TI Determination of the constant coefficient in scale similarity models of turbulence SO PHYSICS OF FLUIDS LA English DT Article AB Scale similarity models are discussed for the subgrid-scale stress tensor and subgrid-scale variance of a passive scalar in a turbulent flow. The modeling involves sampling of the resolved fields by applying a spatial filter at a scale greater than the grid spacing of the computational mesh. A method is described for determining the constant of proportionality present in each model. The model constant for the subgrid-scale stress tensor is determined such that the subgrid-scale turbulent kinetic energy is exact on average. The constant is shown to depend on the size of the sampling filter, the turbulence Reynolds number and the degree of resolution of the large eddies. (C) 1997 American Institute of Physics. RP Cook, AW (reprint author), LOS ALAMOS NATL LAB,APPL THEORET & COMPUTAT PHYS DIV,NUCL & HYDRODYNAM APPLICAT GRP,LOS ALAMOS,NM 87545, USA. NR 10 TC 32 Z9 33 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAY PY 1997 VL 9 IS 5 BP 1485 EP 1487 DI 10.1063/1.869271 PG 3 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA WW801 UT WOS:A1997WW80100035 ER PT J AU Finn, JM Nebel, R Glasser, A Lewis, HR AF Finn, JM Nebel, R Glasser, A Lewis, HR TI Orbital resonances and chaos in a combined rf trap SO PHYSICS OF PLASMAS LA English DT Article ID PURE ELECTRON-PLASMA AB The rf combined trap for confining a non-neutral plasma by a combination of rf fields and a uniform magnetic field is introduced. The particle motion is studied in such a trap in which the rf fields are given by the TM011 mode. The aim is to determine limits on a focus at the center for low angular momentum particles. Such a focus allows densities in excess of the local Brillouin limit, The motion is described in terms of an effective potential consisting of the ponderomotive potential V-pon(r,z) plus a radial potential m Omega(c)(2)r(2)/8 due to the magnetic field B-z plus a centrifugal potential p(theta)(2)/2mr(2). Near the origin r = 0, z = 0, the equations reduce to a pair of Mathieu equations for the r and z motions, For certain parameters the system is quasispherically symmetric, i.e. the effective ponderomotive frequencies Omega(r), Omega(z) in r and z are equal. In this case the Brillouin limit for a uniform density plasma is shown to equal the usual cylindrical limit, Numerical integration of the ponderomotive equations is shown for parameters near those giving quasispherical symmetry, There is resonance for Omega(r)/Omega(z) = 1, giving in = 2, n = 2 islands. The islands limit the size of the focus at the origin, even for p(theta) = 0. For particles with large effective energy E-eff, there can also be chess, depending on the elongation L/a of the rf cavity. It is found that the deleterious effect of islands and chaos on the focus is minimized by having the elongation L/a close to unity and having particles trapped deeply in the ponderomotive well. (C) 1997 American Institute of Physics. C1 DARTMOUTH COLL,DEPT PHYS & ASTRON,HANOVER,NH 03755. RP Finn, JM (reprint author), LOS ALAMOS NATL LAB,T-15,MS K717,LOS ALAMOS,NM 87545, USA. NR 18 TC 2 Z9 2 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1238 EP 1248 DI 10.1063/1.872303 PN 1 PG 11 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600007 ER PT J AU Mikkelsen, DR Manickam, J Scott, SD Zarnstorff, MC AF Mikkelsen, DR Manickam, J Scott, SD Zarnstorff, MC TI Deuterium-tritium simulations of the enhanced reversed shear mode in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETIC SHEAR; PARTICLE-TRANSPORT; TFTR; CONFINEMENT; PLASMAS; PERFORMANCE; STABILITY; BETA AB The potential performance, in deuterium-tritium plasmas, of a new enhanced confinement regime with reversed magnetic shear [enhanced reversed shear (ERS) mode] is assessed. The equilibrium conditions for an ERS mode plasma are estimated by solving the plasma transport equations using the thermal and particle diffusivities measured in a short duration ERS mode discharge in the Tokamak Fusion Test Reactor [F. M. Levinton et al., Phys. Rev. Lett. 75, 4417 (1995)], The plasma performance depends strongly on Z(eff) and neutral beam penetration to the care. The steady-state projections typically have a central electron density of similar to 2.5 x 10(20) m(-3) and nearly equal central electron and ion temperatures of similar to 10 keV. In time-dependent simulations the peak fusion power, similar to 25 MW, is twice the steady-state level. Peak performance occurs during the density rise when the central ion temperature is close to the optimal value of similar to 15 keV. The simulated pressure profiles can be stable to ideal magnetohydrodynamic instabilities with toroidal mode number n = 1,2,3,4 and infinity for beta(norm) up to 2.5; the simulations have beta(norm) less than or equal to 2.1. The enhanced reversed shear mode may thus provide an opportunity to conduct alpha physics experiments in conditions similar to those proposed for advanced tokamak reactors. (C) 1997 American Institute of Physics. RP Mikkelsen, DR (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 40 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1316 EP 1325 DI 10.1063/1.872307 PN 1 PG 10 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600013 ER PT J AU Krommes, JA AF Krommes, JA TI Submarginal profiles and turbulent transport: An exactly solvable model SO PHYSICS OF PLASMAS LA English DT Article ID DRIFT-WAVE TURBULENCE; RIGOROUS UPPER-BOUNDS; PASSIVE ADVECTION; MAGNETIC SHEAR; CONFINEMENT; SIMULATIONS; TRANSITION; STABILITY; DYNAMICS; TFTR AB The possibility that linearly stable (''submarginal'') profiles can support turbulent transport in the absence of external noise is considered in the context of a one-dimensional, realizable stochastic model of ''almost passive'' advection that includes a stability threshold dependent on a critical gradient. The important limits of zero and infinite Kubo number (dimensionless autocorrelation time) are solved analytically. When the stability threshold is linear, it is proven rigorously that, within the context of the model, submarginal profiles do not carry any turbulent flux, A generalization to include a nonlinear stability threshold reminiscent of a subcritical bifurcation supports submarginal profiles. (C) 1997 American Institute of Physics. RP Krommes, JA (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 50 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1342 EP 1356 DI 10.1063/1.872496 PN 1 PG 15 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600016 ER PT J AU Mikkelsen, DR Scott, SD Dorland, W AF Mikkelsen, DR Scott, SD Dorland, W TI Testing the rho(*) scaling of thermal transport models: Predicted and measured temperatures in the Tokamak Fusion Test Reactor dimensionless scaling experiments SO PHYSICS OF PLASMAS LA English DT Article ID PLASMA-CONFINEMENT; GYRO-BOHM; TFTR; DISCHARGES; PRINCIPLES; CODE AB Theoretical predictions of ion and electron thermal diffusivities an tested by comparing calculated and measured temperatures in low (L) mode plasmas from the Tokamak Fusion Test Reactor [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)] nondimensional scaling experiments. The DIII-D [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)] L-mode rho* scalings, the transport models of Rebut-Lalliaa-Watkins (RLW), Boucher's modification of RLW, and the Institute for Fusion Studies-Princeton Plasma Physics Laboratory (IFS-PPPL) model for transport due to ion temperature gradient modes are tested. The predictions use the measured densities in order to include the effects of density profile shape variations on the transport models. The uncertainties in the measured and predicted temperatures are discussed. The predictions based on the DIII-D scalings are within the measurement uncertainties. All the theoretical models predict a more favorable rho* dependence for the ion temperatures than is seen. Preliminary estimates indicate that sheared flow stabilization is important for some discharges, and that inclusion of its effects may bring the predictions of the IFS-PPPL model into agreement with the experiments. (C) 1997 American Institute of Physics. C1 UNIV TEXAS, INST FUS STUDIES, AUSTIN, TX 78712 USA. RP Mikkelsen, DR (reprint author), PRINCETON PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. RI Dorland, William/B-4403-2009 OI Dorland, William/0000-0003-2915-724X NR 31 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1362 EP 1370 DI 10.1063/1.872311 PN 1 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600018 ER PT J AU Shaing, KC Hazeltine, RD Zarnstorff, MC AF Shaing, KC Hazeltine, RD Zarnstorff, MC TI Effects of orbit squeezing on ion transport processes close to magnetic axis SO PHYSICS OF PLASMAS LA English DT Article ID CONFINEMENT; PLASMAS AB It is shown that ion thermal conductivity close to the magnetic axis in tokamaks is reduced by a factor of \S\(5/3) if (M-i/M-e)(2/3)(T-e/T-i)(4/3)/\S\(5/3)much greater than 1. Here, S is the orbit squeezing factor, M-i(M-e) is the ion (electron) mass, and T-i(T-e) is the ion (electron) temperature. The reduction reflects both the increase of the fraction of trapped particles by a factor of \S\(1/3), and the decrease of the orbit size in units of the poloidal flu?; psi by a factor of \S\(2/3). (C) 1997 American Institute of Physics. C1 PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Shaing, KC (reprint author), UNIV TEXAS,INST FUS STUDIES,AUSTIN,TX 78712, USA. NR 12 TC 18 Z9 18 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1371 EP 1374 DI 10.1063/1.872312 PN 1 PG 4 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600019 ER PT J AU Shaing, KC Hazeltine, RD Zarnstorff, MC AF Shaing, KC Hazeltine, RD Zarnstorff, MC TI Electron transport processes close to magnetic axis in tokamaks SO PHYSICS OF PLASMAS LA English DT Article ID PLASMAS; REGION AB Electron transport fluxes valid in the legion close to magnetic axis in tokamaks are derived from the moment equation approach. It is found that bootstrap current does not vanish on the axis, electrical conductivity is reduced from its classical value, and particle and heat fluxes are enhanced over those in the conventional neoclassical theory. The reason for the deviation from the conventional theory is because the fraction of the trapped particles is finite in the region close to the magnetic axis. The existence of the bootstrap current on the magnetic axis may reduce or eliminate the need of the seed current. (C) 1997 American Institute of Physics. C1 PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Shaing, KC (reprint author), UNIV TEXAS,INST FUS STUDIES,AUSTIN,TX 78712, USA. NR 12 TC 20 Z9 20 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1375 EP 1378 DI 10.1063/1.872313 PN 1 PG 4 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600020 ER PT J AU Watt, RG Wilson, DC Chrien, RE Hollis, RV Gobby, PL Mason, RJ Kopp, RA Lerche, RA Kalantar, DH MacGowan, B Nelson, MB Phillips, T McKenty, PW Willi, O AF Watt, RG Wilson, DC Chrien, RE Hollis, RV Gobby, PL Mason, RJ Kopp, RA Lerche, RA Kalantar, DH MacGowan, B Nelson, MB Phillips, T McKenty, PW Willi, O TI Foam-buffered spherical implosions at 527 nm SO PHYSICS OF PLASMAS LA English DT Article ID LASER-BEAM; BURNTHROUGH EXPERIMENTS; TARGETS; DRIVEN; DESIGN; LAYERS AB Creation of a low density, high temperature plasma buffer between the absorption and ablation layers of a directly driven inertial confinement fusion implosion capsule has been proposed as a means to reduce ''early time'' imprint from laser nonuniformities. This thermal smoothing blanket might be created from a low density foam layer wrapped around the deuterium-tritium filled microballoon. Preliminary spherical implosion tests of this concept using a polystyrene foam layer surrounding a glass microballoon were performed at the Nova laser [Rev. Sci. Instrum. 57, 2101 (1986)], using a 527 nm drive wavelength. Comparison of capsule yield and imploded core symmetry showed promising improvements in overall target performance, relative to one-dimensional undegraded hydrodynamic simulations, when the foam-buffer layer was present. (C) 1997 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14627. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON,ENGLAND. RP Watt, RG (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 21 TC 15 Z9 16 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1379 EP 1384 DI 10.1063/1.872568 PN 1 PG 6 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600021 ER PT J AU Lal, AK Gordon, D Wharton, K Clayton, CE Marsh, KA Mori, WB Joshi, C Everett, MJ Johnston, TW AF Lal, AK Gordon, D Wharton, K Clayton, CE Marsh, KA Mori, WB Joshi, C Everett, MJ Johnston, TW TI Spatio-temporal dynamics of the resonantly excited relativistic plasma wave driven by a CO2 laser SO PHYSICS OF PLASMAS LA English DT Article ID COLLECTIVE THOMSON SCATTERING; STIMULATED COMPTON-SCATTERING; ACCELERATION; EXCITATION; SIMULATIONS; INSTABILITY; FREQUENCY; EVOLUTION; ELECTRON; LIGHT AB The dynamics of a relativistic plasma wave (RPW) resonantly excited by a two frequency CO2 laser pulse and the effects of this wave on a co-propagating relativistic electron beam were studied through experiments and supporting simulations. The amplitude of the RPW and its harmonics were resolved in time and space with a Thomson scattering diagnostic. In addition, the plasma wave amplitude-length product and temporal duration were independently measured through time and frequency resolved forward scattering, The transverse electric and magnetic fields associated with the RPW were studied by the scattering of a 2 MeV electron beam, and the eventual heating of the plasma after the breakup of the RPW tvas measured from the x-ray radiation spectrum. The experiments and simulations show that the RPW reaches a peak amplitude of approximately 30%, with the amplitude Limited by plasma blowout driven by the radial ponderomotive forces of the plasma wave. (C) 1997 American Institute of Physics. C1 UNIV CALIF LOS ANGELES,DEPT ELECT ENGN,LOS ANGELES,CA 90024. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. INST NATL RECH SCI ENERGIE VARENNES,VARENNES,PQ,CANADA. NR 35 TC 17 Z9 17 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1434 EP 1447 DI 10.1063/1.872318 PN 1 PG 14 WC Physics, Fluids & Plasmas SC Physics GA WY646 UT WOS:A1997WY64600027 ER PT J AU Matzen, MK AF Matzen, MK TI Z pinches as intense x-ray sources for high-energy density physics applications SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID WIRE; IMPLOSIONS; EMISSION; FUSION AB Fast Z-pinch implosions can efficiently convert the stored electrical energy in a pulsed-power accelerator into x rays. These x rays are produced when an imploding cylindrical plasma, driven by the magnetic field pressure associated with very large axial currents, stagnates upon the cylindrical axis of symmetry. On the Saturn pulsed-power accelerator [R. B. Spielman et al., in Proceedings of the 2nd International Conference on Dense Z Pinches, Laguna Beach, CA, 1989, edited by N. R. Pereira, J. Davis, and N. Rostoker (American Institute of Physics, New York, 1989), p. 3] at Sandia National Laboratories, for example, currents of 6-8 MA with a rise time of less than 50 ns are driven through cylindrically symmetric loads, producing implosion velocities as high as 10(8) cm/s, and x-ray energies exceeding 400 kJ. Hydromagnetic Rayleigh-Taylor instabilities and cylindrical load symmetry are critical, limiting factors in determining the assembled plasma densities and temperatures, and thus in the x-ray energies and pulse widths that can be produced on these accelerators. In recent experiments on the Saturn accelerator, these implosion nonuniformities have been minimized by using wire arrays with as many as 192 wires. Increasing the wire number produced significant improvements in the pinched plasma quality, reproducibility, and x-ray output power. X-ray pulse widths of less than 5 ns and peak powers of 75+/-10 TW have been achieved with arrays of 120 tungsten wires. Similar loads have recently been fielded on the Particle Beam Fusion Accelerator (PBFA II), producing x-ray energies in excess of 1.8 MJ at powers in excess of 160 TW. These intense x-ray sources offer the potential for performing many new basic physics and fusion-relevant experiments. (C) 1997 American Institute of Physics. RP Matzen, MK (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 33 TC 238 Z9 249 U1 2 U2 16 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1519 EP 1527 DI 10.1063/1.872323 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700003 ER PT J AU Breizman, BN Berk, HL Pekker, MS Porcelli, F Stupakov, GV Wong, KL AF Breizman, BN Berk, HL Pekker, MS Porcelli, F Stupakov, GV Wong, KL TI Critical nonlinear phenomena for kinetic instabilities near threshold SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID INDUCED ALFVEN EIGENMODE; ON-TAIL INSTABILITY; PLASMA; SIMULATION; MODES; CONFINEMENT; EVOLUTION; IONS; PDX AB A universal integral equation has been derived and solved for the nonlinear evolution of collective modes driven by kinetic wave particle resonances just above the threshold for instability. The dominant nonlinearity stems from the dynamics of resonant particles that can be treated perturbatively near the marginal state of the system. With a resonant particle source and classical relaxation processes included, the new equation allows the determination of conditions for a soft nonlinear regime, where the saturation level is proportional to the increment above threshold, or a hard nonlinear regime, characterized by explosive behavior, where the saturation level is independent of the closeness to threshold. In the hard regime, rapid oscillations typically arise that lead to large frequency shifts in a fully developed nonlinear stage. The universality of the approach suggests that the theory applies to many types of resonant particle driven instabilities, and several specific cases, viz. energetic particle driven Alfven wave excitation, the fishbone oscillation, and a collective mode in particle accelerators, are discussed. (C) 1997 American Institute of Physics. C1 POLITECN TORINO, DIPARTIMENTO ENERGET, I-10129 TURIN, ITALY. STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, PRINCETON, NJ 08543 USA. BUDKER INST NUCL PHYS, NOVOSIBIRSK 630090, RUSSIA. RP Breizman, BN (reprint author), UNIV TEXAS, INST FUS STUDIES, AUSTIN, TX 78712 USA. NR 42 TC 80 Z9 80 U1 1 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1559 EP 1568 DI 10.1063/1.872286 PN 2 PG 10 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700007 ER PT J AU Fredrickson, ED Sabbagh, SA Bell, MG Mansfield, D Batha, S Chang, Z Levinton, F McGuire, KM Okabayashi, M Taylor, G Takahashi, H Hughes, M Manickam, J Phillips, M Zakharov, L AF Fredrickson, ED Sabbagh, SA Bell, MG Mansfield, D Batha, S Chang, Z Levinton, F McGuire, KM Okabayashi, M Taylor, G Takahashi, H Hughes, M Manickam, J Phillips, M Zakharov, L TI The stability of advanced operational regimes on the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID IMPROVED CONFINEMENT; LIMIT DISRUPTIONS; TEARING MODES; TFTR; SHEAR AB The performance of the Tokamak Fusion Test Reactor [D. Meade and the TFTR Group, in Plasma Physics and Controlled Nuclear Fusion Research, Washington, D.C., 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. I, pp. 9-24], as defined by the maximum fusion power production, has been limited, not by confinement, but by stability to pressure-driven modes. Two classes of current profile modification have been investigated to overcome this limit. A new technique has been developed to increase the internal inductance of low-q (q approximate to 4), high-current (Ip>2MA) plasmas. As was the case at higher edge q, the disruptive beta limit has been found to increase roughly Linearly with the internal inductance, l(i). Plasmas with hollow current profiles, i.e., reversed shear, are also predicted and experimentally observed to have increased stability in the negative shear region to ballooning and kink modes. However, performance of these plasmas is still limited by pressure-driven modes in the normal shear region. (C) 1997 American Institute of Physics. C1 COLUMBIA UNIV,NEW YORK,NY 10027. FUS PHYS & TECHNOL,TORRANCE,CA 90503. NORTHRUP GRUMMAN AEROSP,PLAINSBORO,NJ 08536. RP Fredrickson, ED (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Sabbagh, Steven/C-7142-2011 NR 29 TC 12 Z9 13 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1589 EP 1595 DI 10.1063/1.872290 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700011 ER PT J AU Chang, Z Nazikian, R Fu, GY White, RB Zweben, SJ Fredrickson, ED Batha, SH Bell, MG Bell, RE Budny, RV Bush, CE Chen, L Cheng, CZ Darrow, D LeBlanc, B Levinton, FM Majeski, RP Mansfield, DK McGuire, KM Park, HK Rewoldt, G Synakowski, EJ Tang, WM Taylor, G vonGoeler, S Wong, KL Zakharov, L AF Chang, Z Nazikian, R Fu, GY White, RB Zweben, SJ Fredrickson, ED Batha, SH Bell, MG Bell, RE Budny, RV Bush, CE Chen, L Cheng, CZ Darrow, D LeBlanc, B Levinton, FM Majeski, RP Mansfield, DK McGuire, KM Park, HK Rewoldt, G Synakowski, EJ Tang, WM Taylor, G vonGoeler, S Wong, KL Zakharov, L TI Alpha-driven magnetohydrodynamics (MHD) and MHD-induced alpha loss in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID TOROIDAL ALFVEN EIGENMODES; KINETIC BALLOONING MODES; TFTR; PLASMAS; SHEAR; EXCITATION; PARTICLES; IONS AB Alpha-driven toroidal Alfven eigenmodes (TAEs) are observed as predicted by theory in the post-neutral beam phase in high central q (safety factor) deuterium-tritium (D-T) plasmas in the Tokamak Fusion Test Reactor (TFTR) [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. The mode location, poloidal structure, and the importance of q profile for TAE instability are discussed. So far no alpha particle loss due to these modes was detected due to the small mode amplitude. However, alpha loss induced by kinetic ballooning modes (KBMs) was observed in high-confinement D-T discharges. Particle orbit simulation demonstrates that the wave-particle resonant interaction can explain the observed correlation between the increase in alpha loss and appearance of multiple high-n (n greater than or equal to 6, n is the toroidal mode number) modes. RP Chang, Z (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI chen, liu/I-2297-2013; White, Roscoe/D-1773-2013; Cheng, Chio/K-1005-2014 OI White, Roscoe/0000-0002-4239-2685; NR 40 TC 13 Z9 13 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1610 EP 1616 DI 10.1063/1.872363 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700014 ER PT J AU Krasheninnikov, SI Pigarov, AY Knoll, DA LaBombard, B Lipschultz, B Sigmar, DJ Soboleva, TK Terry, JL Wising, F AF Krasheninnikov, SI Pigarov, AY Knoll, DA LaBombard, B Lipschultz, B Sigmar, DJ Soboleva, TK Terry, JL Wising, F TI Plasma recombination and molecular effects in tokamak divertors and divertor simulators SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID CONFIGURATION INTERACTION; HEH+; ION AB Analysis of the experimental data from tokamaks and linear divertor simulators lends to the conclusion that plasma recombination is a crucial element of plasma detachment. Different mechanisms of plasma recombination relevant to the experimental conditions of the tokamak scrape-off layer (SOL) and divertor simulators are considered. The physics of Molecular Activated Recombination (MAR) involving vibrationally excited molecular hydrogen are discussed. Although conventional Electron-ion Recombination (EIR) alone can strongly alter the plasma parameters, MAR impact can be substantial for both tokamak SOL plasma and divertor simulators, Investigation of the effects of EIR on the plasma flow in divertor simulators shows that due to the balances of (a) energy transport and electron cooling, and (b) the plasma flow and recombination, that EIR extinguishes the simulator plasma at an electron temperature about 0.15 eV. (C) 1997 American Institute of Physics. C1 IV KURCHATOV ATOM ENERGY INST,MOSCOW 123182,RUSSIA. COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV NACL AUTONOMA MEXICO,INST CIENCIAS NUCL,MEXICO CITY 04510,DF,MEXICO. CHALMERS UNIV TECHNOL,INST ELECTROMAGNET FIELD THEORY,S-41296 GOTHENBURG,SWEDEN. RP Krasheninnikov, SI (reprint author), MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139, USA. RI Lipschultz, Bruce/J-7726-2012 OI Lipschultz, Bruce/0000-0001-5968-3684 NR 37 TC 76 Z9 76 U1 2 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1638 EP 1646 DI 10.1063/1.872268 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700018 ER PT J AU Sauter, O LaHaye, RJ Chang, Z Gates, DA Kamada, Y Zohm, H Bondeson, A Boucher, D Callen, JD Chu, MS Gianakon, TA Gruber, O Harvey, RW Hegna, CC Lao, LL Monticello, DA Perkins, F Pletzer, A Reiman, AH Rosenbluth, M Strait, EJ Taylor, TS Turnbull, AD Waelbroeck, F Wesley, JC Wilson, HR Yoshino, R AF Sauter, O LaHaye, RJ Chang, Z Gates, DA Kamada, Y Zohm, H Bondeson, A Boucher, D Callen, JD Chu, MS Gianakon, TA Gruber, O Harvey, RW Hegna, CC Lao, LL Monticello, DA Perkins, F Pletzer, A Reiman, AH Rosenbluth, M Strait, EJ Taylor, TS Turnbull, AD Waelbroeck, F Wesley, JC Wilson, HR Yoshino, R TI Beta limits in long-pulse tokamak discharges SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID TEARING MODE; NONLINEAR DYNAMICS; BOOTSTRAP CURRENT; MAGNETIC ISLANDS; MHD MODES; STABILITY; PLASMAS; PRESSURE; TFTR AB The maximum normalized beta achieved in long-pulse tokamak discharges at low collisionality falls significantly below both that observed in short pulse discharges and that predicted by the ideal MHD theory. Recent long-pulse experiments, in particular those simulating the International Thermonuclear Experimental Reactor (ITER) [M. Rosenbluth et al., Plasma Physics and Controlled Nuclear Fusion (International Atomic Energy Agency, Vienna, 1995), Vol. 2, p. 517] scenarios with low collisionality nu(e)*, are often limited by low-m/n nonideal magnetohydrodynamic (MHD) modes. The effect of saturated MHD modes is a reduction of the confinement time by 10%-20%, depending on the island size and location, and can lead to a disruption. Recent theories on neoclassical destabilization of tearing modes, including the effects of a perturbed helical bootstrap current, are successful in explaining the qualitative behavior of the resistive modes and recent results are consistent with the size of the saturated islands. Also, a strong correlation is observed between the onset of these low-m/n modes with sawteeth, edge localized modes (ELM), or fishbone events. consistent with the seed island required by the theory. We will focus on a quantitative comparison between both the conventional resistive and neoclassical theories, and the experimental results of several machines, which have all observed these low-min nonideal modes. This enables us to single out the key issues in projecting the long-pulse beta limits of ITER-size tokamaks and also to discuss possible plasma control methods that can increase the soft beta limit, decrease the seed perturbations, and/or diminish the effects on confinement. (C) 1997 American Institute of Physics. C1 UNIV STUTTGART, IPF, D-70569 STUTTGART, GERMANY. JCT, ITER, LA JOLLA, CA 92037 USA. GEN ATOM CO, SAN DIEGO, CA 92186 USA. PRINCETON PLASMA PHYS LAB, PRINCETON, NJ 08540 USA. JAPAN ATOM ENERGY RES INST, NAKA, IBARAKI 31101, JAPAN. MAX PLANCK INST PLASMA PHYS, EURATOM ASSOC, D-85748 GARCHING, GERMANY. CHALMERS UNIV TECHNOL, S-41296 GOTHENBURG, SWEDEN. UNIV WISCONSIN, MADISON, WI 53706 USA. UNIV TEXAS, INST FUS STUDIES, AUSTIN, TX 78712 USA. UKAEA EURATOM FUS ASSOC, CULHAM LAB, ABINGDON OX14 3DB, OXON, ENGLAND. COMPX, DEL MAR, CA 92014 USA. RP Sauter, O (reprint author), PPB ECUBLENS, ASSOC EURATOM SWITZERLAND, CRPP, CH-1015 LAUSANNE, SWITZERLAND. RI Waelbroeck, Francois/B-6988-2008 OI Waelbroeck, Francois/0000-0001-9324-3690 NR 38 TC 325 Z9 328 U1 8 U2 32 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1654 EP 1664 DI 10.1063/1.872270 PN 2 PG 11 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700020 ER PT J AU Batishchev, OV Krasheninnikov, SI Catto, PJ Batishcheva, AA Sigmar, DJ Xu, XQ Byers, JA Rognlien, TD Cohen, RH Shoucri, MM Shkarofskii, IP AF Batishchev, OV Krasheninnikov, SI Catto, PJ Batishcheva, AA Sigmar, DJ Xu, XQ Byers, JA Rognlien, TD Cohen, RH Shoucri, MM Shkarofskii, IP TI Kinetic effects in tokamak scrape-off layer plasmas SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID DIVERTOR; TRANSPORT; PARTICLE; WAVES AB The short mean-free path expansion used in fluid modeling of scrape-off layer plasmas is often violated for typical discharge parameters, especially by the superthermal particles, which carry most of the heat flux. Thus, the tail of the distribution function can strongly depart from Maxwellian due to nonlocal mean-free path effects, which can modify plasma transport, impurity radiation, and plasma-neutral gas interactions. These nonlocal effects become particularly pronounced for detached plasma conditions that are characterized by sharp gradients in the plasma parameters along the magnetic field. These problems are being addressed by developing one spatial dimension and two velocity variables, fully kinetic, collisional, and time-dependent particle-in-cell code, W1 [Contrib. Plasma Phys. 34, 436 (1994)], and its parallel-computer version, PW1 [Contrib. Plasma Phys. 34, 424 (1996)]. Comparisons are made with the Fokker-Planck code ALLA [Phys. Plasmas 3, 1634 (1996)] and with experimental results. Kinetic effects on probe measurement interpretation, impurity radiation, and parallel heat conductivity due to non-Maxwellian features in scrape-off layer plasmas are considered. Heat conductivity is compared with nd hoc heat flux limit models. (C) 1997 American Institute of Physics. C1 MV KELDYSH APPL MATH INST,MOSCOW 125047,RUSSIA. KURCHATOV INST ATOM ENERGY,MOSCOW 123098,RUSSIA. MIT,CTR PLASMA FUS,CAMBRIDGE,MA 02139. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. CTR CANADIEN FUS MAGNET,VARENNES,PQ J3X 1S1,CANADA. RP Batishchev, OV (reprint author), LODESTAR RES CORP,BOULDER,CO 80301, USA. NR 39 TC 49 Z9 49 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1672 EP 1680 DI 10.1063/1.872280 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700022 ER PT J AU Messiaen, AM Ongena, J Unterberg, B Boedo, J Fuchs, G Jaspers, R Konen, L Koslowski, HR Mank, G Rapp, J Samm, U Vandenplas, PE VanOost, G VanWassenhove, G Waidmann, G Weynants, RR Wolf, GH Bertschinger, G Bonheure, G Brix, M Dumortier, P Durodie, F Finken, KH Giesen, B Hillis, D Hutteman, P Koch, R KramerFlecken, A Lyssoivan, A Mertens, P Pospieszczyk, A PostZwicker, A Sauer, M Schweer, B Schwelberger, J Telesca, G Tokar, MZ Uhlemann, R Vervier, M Winter, J AF Messiaen, AM Ongena, J Unterberg, B Boedo, J Fuchs, G Jaspers, R Konen, L Koslowski, HR Mank, G Rapp, J Samm, U Vandenplas, PE VanOost, G VanWassenhove, G Waidmann, G Weynants, RR Wolf, GH Bertschinger, G Bonheure, G Brix, M Dumortier, P Durodie, F Finken, KH Giesen, B Hillis, D Hutteman, P Koch, R KramerFlecken, A Lyssoivan, A Mertens, P Pospieszczyk, A PostZwicker, A Sauer, M Schweer, B Schwelberger, J Telesca, G Tokar, MZ Uhlemann, R Vervier, M Winter, J TI High confinement and high density with stationary plasma energy and strong edge radiation cooling in the upgraded Torus experiment for technology oriented research (TEXTOR-94) SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID OHMIC DISCHARGES; TOKAMAKS; BEAM; PERFORMANCE; IMPURITIES; BOUNDARY; EXHAUST AB An overview of the results obtained so far for the radiative I-mode regime on the upgraded Torus Experiment for Technology Oriented Research (TEXTOR-94) [Proceedings of die 16th IEEE Symposium on Fusion Engineering (Institute of Electrical and Electronics Engineers, Piscataway, NJ, 1995), Vol. 1, p. 470] is given. This regime is obtained under quasistationary conditions with edge neon seeding in a pumped limiter tokamak with circular cross section. It combines high confinement and high beta (up to a normalized beta, beta(n) = 2) with low edge q values (down to q(a) = 2.8) and high density even above the Greenwald limit together with dominant edge radiative heat exhaust, and therefore shows promise for the future of fusion research. Bulk and edge properties of these discharges an described, and a detailed account is given of the energy and particle confinement and their scaling. Energy confinement scales linearly with density as for the nonsaturated Ohmic Neo-Alcator scaling, but the usual degradation with total power remains. No deleterious effects of the neon seeding on fusion reactivity and plasma stability have been observed. (C) 1997 American Institute of Physics. C1 FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST PLASMAPHYS, EURATOM ASSOC, D-52425 JULICH, GERMANY. UNIV CALIF SAN DIEGO, FUS ENERGY RES PROGRAM, MECH ENGN DIV, LA JOLLA, CA 92093 USA. EURATOM, FOM, INST PLASMAFYS RIJNHUIZEN ASSOCIATIE, NIEUWEGEIN, NETHERLANDS. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. NFSR, LIEGE, BELGIUM. RP Messiaen, AM (reprint author), ECOLE ROYALE MIL, LAB PHYS PLASMAS, ASSOC EURATOM BELGIAN STATE, B-1000 BRUSSELS, BELGIUM. NR 33 TC 51 Z9 51 U1 4 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1690 EP 1698 DI 10.1063/1.872343 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700024 ER PT J AU Park, HK Sabbagh, SA Batha, S Bell, M Budny, RV Bush, C Chang, Z Johnson, D Mansfield, DK McCune, D McGuire, KM Nazikian, R Skinner, C Wieland, R Yamada, M Young, KM AF Park, HK Sabbagh, SA Batha, S Bell, M Budny, RV Bush, C Chang, Z Johnson, D Mansfield, DK McCune, D McGuire, KM Nazikian, R Skinner, C Wieland, R Yamada, M Young, KM TI The role of the neutral beam fueling profile in the performance of the Tokamak Fusion Test Reactor and other tokamak plasmas SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID JOINT EUROPEAN TORUS; ENERGY CONFINEMENT; TFTR TOKAMAK; TRITIUM; SUPERSHOTS; DEUTERIUM; INJECTION; TRANSPORT; MODES AB Scalings for the stood energy and neutron yield, determined from experimental data, are applied to both deuterium-only and deuterium-tritium plasmas in different neutral-beam-heated operational domains in the Tokamak Fusion Test Reactor [Nucl. Fusion 25, 1167 (1985)]. The domain of the data considered includes the Supershot, high poloidal beta, low-mode, and limiter high-mode operational regimes, as well as discharges with a reversed magnetic shear configuration. The new important parameter in the present scaling is the peakedness of the heating beam fueling profile shape. Ion energy confinement and neutron production are relatively insensitive to other plasma parameters compared to the beam fueling peakedness parameter and the heating beam power when considering plasmas that are stable to magnetohydrodynamic modes. However, the stored energy of the electrons is independent of the beam fueling peakedness. The implication of the scalings based on this parameter is related to theoretical transport models such as radial electric field shear and ion temperature gradient marginality models. Similar physics interpretation is provided for beam heated discharges on other major tokamaks. C1 COLUMBIA UNIV, NEW YORK, NY 10027 USA. OAK RIDGE NATL LAB, OAK RIDGE, TN USA. RP Park, HK (reprint author), PRINCETON UNIV, PRINCETON PLASMA PHYS LAB, POB 451, PRINCETON, NJ 08543 USA. RI Sabbagh, Steven/C-7142-2011; Yamada, Masaaki/D-7824-2015 OI Yamada, Masaaki/0000-0003-4996-1649 NR 36 TC 9 Z9 9 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1699 EP 1706 DI 10.1063/1.872272 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700025 ER PT J AU Lin, Z Tang, WM Lee, WW AF Lin, Z Tang, WM Lee, WW TI Large orbit neoclassical transport SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID REVERSED MAGNETIC SHEAR; PARTICLE SIMULATION; TOKAMAK PLASMAS; CONFINEMENT; FLOW AB Neoclassical transport in the presence of large ion orbits is investigated. The study is motivated by the recent experimental results that ion thermal transport levels in enhanced confinement tokamak plasmas fall below the ''irreducible minimum level'' predicted by standard neoclassical theory. This apparent contradiction is resolved in the present analysis by relaxing the basic neoclassical assumption that the ions orbital excursions are much smaller than the local toroidal minor radius and the equilibrium scale lengths of the system. Analytical and simulation results are in agreement with trends from experiments. The development of a general formalism for neoclassical transport theory with finite orbit width is also discussed. (C) 1997 American Institute of Physics. RP Lin, Z (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 20 TC 27 Z9 27 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1707 EP 1713 DI 10.1063/1.872273 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700026 ER PT J AU Bell, MG Batha, S Beer, M Bell, RE Belov, A Berk, H Bemabei, S Bitter, M Breizman, B Bretz, NL Budny, R Bush, CE Callen, J Cauffman, S Chang, CS Chang, Z Cheng, CZ Darrow, DS Dendy, RO Dorland, W Duong, H Efthimion, PC Ernst, D Evenson, H Fisch, NJ Fisher, R Fonck, RJ Fredrickson, ED Fu, GY Furth, HP Gorelenkov, NN Goloborodko, VY Grek, B Grisham, LR Hammett, GW Hawryluk, RJ Heidbrink, W Herrmann, HW Hermann, MC Hill, KW Hogan, J Hooper, B Hosea, JC Houlberg, WA Hughes, M Jassby, DL Jobes, FC Johnson, DW Kaita, R Kaye, S Kesner, J Kim, JS Kissick, M Krasilnikov, AV Kugel, H Kumar, A Lam, NT Lamarche, P LeBlanc, B Levinton, FM Ludescher, C Machuzak, J Majeski, RP Manickam, J Mansfield, DK Mauel, M Mazzucato, E McChesney, J McCune, DC McKee, G McGuire, KM Meade, DM Medley, SS Mikkelsen, DR Mirnov, SV Mueller, D Nagayama, Y Navratil, GA Nazikian, R Okabayashi, M Osakabe, M Owens, DK Park, HK Park, W Paul, SF Petrov, MP Phillips, CK Phillips, M Phillips, P Ramsey, AT Rice, B Redi, MH Rewoldt, G Reznik, S Roquemore, AL Rogers, J Ruskov, E Sabbagh, SA Sasao, M Schilling, G Schmidt, GL Scott, SD Semenov, I Senko, T Skinner, CH Stevenson, T Strait, EJ Stratton, BC Strachan, JD Stodiek, W Synakowski, E Takahashi, H Tang, W Taylor, G Thompson, MW vonGoeler, S VonHalle, A Walters, RT Wang, S White, R Wieland, RM Williams, M Wilson, JR Wong, KL Wurden, GA Yamada, M Yavorski, V Young, KM Zakharov, L Zarnstorff, MC Zweben, SJ AF Bell, MG Batha, S Beer, M Bell, RE Belov, A Berk, H Bemabei, S Bitter, M Breizman, B Bretz, NL Budny, R Bush, CE Callen, J Cauffman, S Chang, CS Chang, Z Cheng, CZ Darrow, DS Dendy, RO Dorland, W Duong, H Efthimion, PC Ernst, D Evenson, H Fisch, NJ Fisher, R Fonck, RJ Fredrickson, ED Fu, GY Furth, HP Gorelenkov, NN Goloborodko, VY Grek, B Grisham, LR Hammett, GW Hawryluk, RJ Heidbrink, W Herrmann, HW Hermann, MC Hill, KW Hogan, J Hooper, B Hosea, JC Houlberg, WA Hughes, M Jassby, DL Jobes, FC Johnson, DW Kaita, R Kaye, S Kesner, J Kim, JS Kissick, M Krasilnikov, AV Kugel, H Kumar, A Lam, NT Lamarche, P LeBlanc, B Levinton, FM Ludescher, C Machuzak, J Majeski, RP Manickam, J Mansfield, DK Mauel, M Mazzucato, E McChesney, J McCune, DC McKee, G McGuire, KM Meade, DM Medley, SS Mikkelsen, DR Mirnov, SV Mueller, D Nagayama, Y Navratil, GA Nazikian, R Okabayashi, M Osakabe, M Owens, DK Park, HK Park, W Paul, SF Petrov, MP Phillips, CK Phillips, M Phillips, P Ramsey, AT Rice, B Redi, MH Rewoldt, G Reznik, S Roquemore, AL Rogers, J Ruskov, E Sabbagh, SA Sasao, M Schilling, G Schmidt, GL Scott, SD Semenov, I Senko, T Skinner, CH Stevenson, T Strait, EJ Stratton, BC Strachan, JD Stodiek, W Synakowski, E Takahashi, H Tang, W Taylor, G Thompson, MW vonGoeler, S VonHalle, A Walters, RT Wang, S White, R Wieland, RM Williams, M Wilson, JR Wong, KL Wurden, GA Yamada, M Yavorski, V Young, KM Zakharov, L Zarnstorff, MC Zweben, SJ TI Deuterium-tritium plasmas in novel regimes in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID REVERSED MAGNETIC SHEAR; DIII-D; CONFINEMENT; TFTR; STABILITY AB Experiments in the Tokamak Fusion Test Reactor (TFTR) [Phys. Plasmas 2, 2176 (1995)] have explored several novel regimes of improved tokamak confinement in deuterium-tritium (D-T) plasmas, including plasmas with reduced or reversed magnetic shear in the core and high-current plasmas with increased shear in the outer region (high l(i)). New techniques have also been developed to enhance the confinement in these regimes by modifying the plasma-limiter interaction through in situ deposition of lithium. In reversed-shear plasmas, transitions to enhanced confinement have been observed at plasma currents up to 2.2 MA (q(a) approximate to 4.3), accompanied by the formation of internal transport barriers, where large radial gradients develop in the temperature and density profiles. Experiments have been performed to elucidate the mechanism of the barrier formation and its relationship with the magnetic configuration and with the heating characteristics. The increased stability of high-current, high-l(i) plasmas produced by rapid expansion of the minor cross section, coupled with improvement in the confinement by lithium deposition has enabled the achievement of high fusion power, up to 8.7 MW, with D-T neutral beam heating. The physics of fusion alpha-particle confinement has been investigated in these regimes, including the interactions of the alphas with endogenous plasma instabilities and externally applied waves in the ion cyclotron range of frequencies. In D-T plasmas with q(0) > 1 and weak magnetic shear in the central region, a toroidal Alfven eigenmode instability driven purely by the alpha particles has been observed for the first time. The interactions of energetic ions with ion Bernstein waves produced by mode conversion from fast waves in mixed-species plasmas have been studied as a possible mechanism for transferring the energy of the alphas to fuel ions. (C) 1997 American Institute of Physics. RP Bell, MG (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Sabbagh, Steven/C-7142-2011; Hammett, Gregory/D-1365-2011; Ernst, Darin/A-1487-2010; Dendy, Richard/A-4533-2009; Dorland, William/B-4403-2009; White, Roscoe/D-1773-2013; Cheng, Chio/K-1005-2014; Yamada, Masaaki/D-7824-2015; Wurden, Glen/A-1921-2017 OI Hammett, Gregory/0000-0003-1495-6647; Ernst, Darin/0000-0002-9577-2809; Dorland, William/0000-0003-2915-724X; White, Roscoe/0000-0002-4239-2685; Yamada, Masaaki/0000-0003-4996-1649; Wurden, Glen/0000-0003-2991-1484 NR 38 TC 18 Z9 18 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1714 EP 1724 DI 10.1063/1.872274 PN 2 PG 11 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700027 ER PT J AU Synakowski, EJ Batha, SH Beer, MA Bell, MG Bell, RE Budny, RV Bush, CE Efthimion, PC Hahm, TS Hammett, GW LeBlanc, B Levinton, F Mazzucato, E Park, H Ramsey, AT Schmidt, G Rewoldt, G Scott, SD Taylor, G Zarnstorff, MC AF Synakowski, EJ Batha, SH Beer, MA Bell, MG Bell, RE Budny, RV Bush, CE Efthimion, PC Hahm, TS Hammett, GW LeBlanc, B Levinton, F Mazzucato, E Park, H Ramsey, AT Schmidt, G Rewoldt, G Scott, SD Taylor, G Zarnstorff, MC TI Local transport barrier formation and relaxation in reverse-shear plasmas on the tokamak fusion test reactor SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID DIII-D TOKAMAK; MAGNETIC SHEAR; FLOW SHEAR; MODE; CONFINEMENT; FIELD; TURBULENCE AB The roles of turbulence stabilization by sheared E x B flow and Shafranov shift gradients are examined for Tokamak Fusion Test Reactor [D. J. Grove and D. M. R Meade, Nucl. Fusion 25, 1167 (1985)] enhanced reverse-shear (ERS) plasmas. Both effects in combination provide the basis of a positive-feedback model that predicts reinforced turbulence suppression with increasing pressure gradient. Local fluctuation behavior at the onset of ERS confinement is consistent with this framework. The power required for transitions into the ERS regime are lower when high power neutral beams are applied earlier in the current profile evolution, consistent with the suggestion that both effects play a role. Separation of the roles of E x B and Shafranov shift effects was performed by varying the EX B shear through changes in the toroidal velocity with nearly steady-state pressure profiles. Transport and fluctuation levels increase only when E x B shearing rates are driven below a critical value that is comparable to the fastest linear growth rates of the dominant instabilities. While a turbulence suppression criterion that involves the ratio of shearing to linear growth rates is in accord with many of these results, the existence of hidden dependencies of the criterion is suggested in experiments where the toroidal field was varied. The forward transition into the ERS regime has also been examined in strongly rotating plasmas. The power threshold is higher with unidirectional injection than with balance injection. (C) 1997 American Institute of Physics. RP Synakowski, EJ (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Hammett, Gregory/D-1365-2011 OI Hammett, Gregory/0000-0003-1495-6647 NR 31 TC 93 Z9 93 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1736 EP 1744 DI 10.1063/1.872275 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700029 ER PT J AU Barnes, DC Mitchell, TB Schauer, MM AF Barnes, DC Mitchell, TB Schauer, MM TI Beyond the Brillouin limit with the penning fusion experiment SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID INERTIAL-ELECTROSTATIC CONFINEMENT; PHYSICS; ION AB Several years ago, it was proposed that a dense non-neutral plasma could be produced in a Penning trap. Nonneutral plasmas have excellent confinement, and such a dense plasma might produce simultaneously high density and good confinement. Recently, this theoretical conjecture has been demonstrated in a small (3 mm radius) electron experiment, PFX (Penning Fusion Experiment). Densities up to 35 times the Brillouin density (limiting number density in a static trap) have been inferred from the observed strong (100:1) spherical focusing. Electrons are injected at low energy from a single pole of the sphere. A surprising observation is the self-organization of the system into a spherical state, which occurs precisely when the trap parameters are adjusted to produce a spherical well. This organization is caused by a bootstrapping mechanism which produces a hysteresis. Observations of energy-scattered electrons confirm the existence of a dense spherical focus. (C) 1997 American Institute of Physics. C1 LOS ALAMOS NATL LAB,DIV PHYS,LOS ALAMOS,NM 87545. RP Barnes, DC (reprint author), LOS ALAMOS NATL LAB,DIV APPL THEORET & COMPUTAT,LOS ALAMOS,NM 87545, USA. NR 16 TC 27 Z9 27 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1745 EP 1751 DI 10.1063/1.872276 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700030 ER PT J AU Fenstermacher, ME Allen, SL Brooks, NH Buchenauer, DA Carlstrom, TN Cuthbertson, JW Doyle, EJ Evans, TE Garbet, PM Harvey, RW Hill, DN Hyatt, AW Isler, RC Jackson, G James, RA Jong, R Klepper, CC Lasnier, CJ Leonard, AW Mahdavi, MA Maingi, R Meyer, WH Moyer, RA Nilson, DG Petrie, TW Porter, GD Rhodes, TL Schaffer, MJ Stambaugh, RD Thomas, DM Tugarinov, S Wade, MR Watkins, JG West, WP Whyte, DG Wood, RD AF Fenstermacher, ME Allen, SL Brooks, NH Buchenauer, DA Carlstrom, TN Cuthbertson, JW Doyle, EJ Evans, TE Garbet, PM Harvey, RW Hill, DN Hyatt, AW Isler, RC Jackson, G James, RA Jong, R Klepper, CC Lasnier, CJ Leonard, AW Mahdavi, MA Maingi, R Meyer, WH Moyer, RA Nilson, DG Petrie, TW Porter, GD Rhodes, TL Schaffer, MJ Stambaugh, RD Thomas, DM Tugarinov, S Wade, MR Watkins, JG West, WP Whyte, DG Wood, RD TI The two-dimensional structure of radiative divertor plasmas in the DIII-D Tokamak SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys AB Recent measurements of the two-dimensional (2-D) spatial profiles of divertor plasma density, temperature, and emissivity in the DIII-D tokamak [J. Luxon et al., in Proceedings of the 11th International Conference on Plasma Physics and Controlled Nuclear Fusion (International Atomic Energy Agency, Vienna, 1987), p. 159] under highly radiating conditions are presented. Data are obtained using a divertor Thomson scattering system and other diagnostics optimized for measuring the high electron densities and low temperatures in these detached divertor plasmas (n(e) less than or equal to 10(21) m(-3), 0.5 eV less than or equal to T-e). D-2 gas injection in the divertor increases the plasma radiation and lowers T-e to less than 2 eV in most of the divertor volume. Modeling shows that this temperature is low enough to allow ion-neutral collisions, charge exchange, and volume recombination to play significant roles in reducing the plasma pressure along the magnetic separatrix by a factor of 3-5, consistent with the measurements. Absolutely calibrated vacuum ultraviolet spectroscopy and 2-D images of impurity emission show that carbon radiation near the X-point, and deuterium radiation near the target plates contribute to the reduction in T-e. Uniformity of radiated power (P-rad) (within a factor of 2) along the outer divertor leg, with peak heat flux on the divertor target reduced fourfold, was obtained. A comparison with 2-D fluid simulations shows good agreement when physical sputtering and an nd hoc chemical sputtering source (0.5%) from the private flux region surface are used. (C) 1997 American Institute of Physics. RP Fenstermacher, ME (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 33 TC 40 Z9 41 U1 2 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1761 EP 1773 DI 10.1063/1.872278 PN 2 PG 13 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700032 ER PT J AU Beer, MA Hammett, GW Rewoldt, G Synakowski, EJ Zarnstorff, MC Dorland, W AF Beer, MA Hammett, GW Rewoldt, G Synakowski, EJ Zarnstorff, MC Dorland, W TI Gyrofluid simulations of turbulence suppression in reversed-shear experiments on the tokamak fusion test reactor SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID MAGNETIC SHEAR; CONFINEMENT; PLASMA; INSTABILITY; MODELS; TFTR AB The confinement improvement in reversed-shear experiments on the Tokamak Fusion Test Reactor [Plasma Phys. Controlled Fusion 26, 11 (1984)] is investigated using nonlinear gyrofluid simulations including a bounce-averaged trapped electron fluid model. This model includes important kinetic effects for both ions and electrons, and agrees well with linear kinetic theory. Both reversed shear and the Shafranov shift reverse the precession drifts of a large fraction of the trapped electrons, which significantly reduces the growth rate of the trapped electron mode, found to be the dominant instability in the core. Two positive feedback transition mechanisms for the sudden improvement in core confinement are discussed: (1) Shafranov shift suppression of the trapped electron mode, and (2) turbulence suppression by radially sheared E x B flows. While both effects appear to be playing roles in the transition dynamics in most experiments, we show that Shafranov shift stabilization alone can cause a transition. (C) 1997 American Institute of Physics. C1 INST FUS STUDIES,AUSTIN,TX 78712. RP Beer, MA (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Hammett, Gregory/D-1365-2011; Dorland, William/B-4403-2009 OI Hammett, Gregory/0000-0003-1495-6647; Dorland, William/0000-0003-2915-724X NR 26 TC 119 Z9 119 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1792 EP 1799 DI 10.1063/1.872279 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700035 ER PT J AU Kirkwood, RK MacGowan, BJ Montgomery, DS Afeyan, BB Kruer, WL Pennington, DM Wilks, SC Moody, JD Wharton, K Back, CA Estabrook, KG Glenzer, SH Blain, MA Berger, RL Hinkel, DE Lasinski, BF Williams, EA Munro, D Wilde, BH Rousseaux, C AF Kirkwood, RK MacGowan, BJ Montgomery, DS Afeyan, BB Kruer, WL Pennington, DM Wilks, SC Moody, JD Wharton, K Back, CA Estabrook, KG Glenzer, SH Blain, MA Berger, RL Hinkel, DE Lasinski, BF Williams, EA Munro, D Wilde, BH Rousseaux, C TI Observation of multiple mechanisms for stimulating ion waves in ignition scale plasmas SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID RAMAN-SCATTERING; ACOUSTIC-WAVES; SATURATION; FREQUENCY; FACILITY AB The laser and plasma conditions expected in ignition experiments using indirect drive inertial confinement have been studied experimentally. It has been shown that there are at least three ways in which ion waves can be stimulated in these plasmas and have a significant effect on the energy balance and distribution in the target. First ion waves can be stimulated by a single laser beam by the process of stimulated Brillouin scattering (SBS) in which an ion acoustic and a scattered electromagnetic wave grow from noise. Second, in a plasma where more than one beam intersects, ion waves can be excited at the ''beat'' frequency and wave number of the intersecting beams, causing the sidescatter instability to be seeded, and substantial energy to be transferred between the beams [R. K. Kirkwood et al., Phys. Rev. Lett. 76, 2065 (1996)]. And third, ion waves may be stimulated by the decay of electron plasma waves produced by stimulated Raman scattering (SRS), thereby inhibiting the SRS process. (C) 1997 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. RP Kirkwood, RK (reprint author), LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. OI Montgomery, David/0000-0002-2355-6242 NR 29 TC 35 Z9 35 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1800 EP 1810 DI 10.1063/1.872293 PN 2 PG 11 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700036 ER PT J AU Olson, RE Porter, JL Chandler, GA Fehl, DL Jobe, DO Leeper, RJ Matzen, MK McGum, JS Noack, DD Ruggles, LE Sawyer, P Torres, JA Vargas, M Zagar, DM Kornblum, HN Orzechowski, TJ Phillion, DW Suter, LJ Thiessen, AR Wallace, RJ AF Olson, RE Porter, JL Chandler, GA Fehl, DL Jobe, DO Leeper, RJ Matzen, MK McGum, JS Noack, DD Ruggles, LE Sawyer, P Torres, JA Vargas, M Zagar, DM Kornblum, HN Orzechowski, TJ Phillion, DW Suter, LJ Thiessen, AR Wallace, RJ TI Inertial confinement fusion ablator physics experiments on Saturn and nova SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID IGNITION; HOT AB The Saturn pulsed power accelerator [R. B. Spielman et al., in Proceedings of the 2nd International Conference on Dense Z-pinches, Laguna Beach, CA, 1989, edited by N. R. Pereira, J. Davis, and N. Rostoker (American Institute of Physics, New York, 1989), p. 3] at Sandia National Laboratories (SNL) and the Nova laser [J. T. Hunt and D. R. Speck, Opt. Eng. 281 161 (1989)] at Lawrence Livermore National Laboratory (LLNL) have been used to explore techniques for studying the behavior of ablator material in x-ray radiation environments comparable in magnitude, spectrum, and duration to those that would be experienced in National Ignition Facility (NTF) hohlraums [J. D. Lindl, Phys. Plasmas 2, 3933 (1995)]. The large x-ray outputs available from the Saturn pulsed-power-driven 2 pinch have enabled us to drive hohlraums of full MF ignition scale size at radiation temperatures and time scales comparable to those required for the low-power foot pulse of an ignition capsule. The high-intensity drives available in the Nova laser have allowed us to study capsule ablator physics in smaller-scale hohlraums at radiation temperatures and time scales relevant to the peak power pulse for an ignition capsule. Taken together, these experiments have pointed the way to possible techniques for testing radiation-hydrodynamics code predictions of radiation flow, opacity, equation of state, and ablator shock velocity over the range of radiation environments that will be encountered in a NIF hohlraum. (C) 1997 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Olson, RE (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 20 TC 25 Z9 25 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1818 EP 1824 DI 10.1063/1.872295 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700038 ER PT J AU Drake, RP Estabrook, K Watt, RG AF Drake, RP Estabrook, K Watt, RG TI Greatly enhanced acoustic noise and the onset of stimulated Brillouin scattering SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID DRIVEN GOLD DISKS; ION-PLASMA WAVES; M LASER-LIGHT; UNDERDENSE PLASMA; HOT-SPOTS; BACKSCATTERING; INSTABILITY; SATURATION; EVOLUTION; FACILITY AB Experiments using near-infrared to ultraviolet lasers offer the potential to study the acoustic noise in plasmas. As the onset of stimulated Brillouin scattering (SBS) has come to be closely examined, the evidence indicates that the acoustic noise may often or always be far above thermal levels. Evidence regarding the noise is reported here, from two recent experiments which confirmed the theoretically anticipated onset behavior for SBS. In one case, the noise appears to be greatly enhanced above thermal levels. In the other case, the data place an upper limit on the noise level. There is physical grounds to believe that enhanced acoustic noise may be ubiquitous in plasmas, even in the absence of plasma instabilities which drive turbulence. (C) 1997 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94551 USA. LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. RP UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 46 TC 3 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1825 EP 1831 DI 10.1063/1.872296 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700039 ER PT J AU Hsing, WW Barnes, CW Beck, JB Hoffman, NM Galmiche, D Richard, A Edwards, J Graham, P Rothman, S Thomas, B AF Hsing, WW Barnes, CW Beck, JB Hoffman, NM Galmiche, D Richard, A Edwards, J Graham, P Rothman, S Thomas, B TI Rayleigh-Taylor instability evolution in ablatively driven cylindrical implosions SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID HYDRODYNAMIC INSTABILITY; LARGE GROWTH; TARGETS; FUSION; PLASMA; SATURATION; STABILITY; LASERS; GAIN; NOVA AB The Rayleigh-Taylor instability is an important limitation in inertial confinement fusion capsule designs. Significant work both theoretically and experimentally has been done to demonstrate the stabilizing effects of material flow through the unstable region, The experimental verification has been done predominantly in planar geometry, Convergent geometry introduces effects not present in planar geometry such as shell thickening and accelerationless growth of modal amplitudes (e.g., Bell-Plesset growth). Amplitude thresholds for the nonlinear regime are reduced, since the wavelength lambda of a mode m decreases with convergence lambda similar to R/m, where R is the radius. Convergent effects have been investigated using an imploding cylinder driven by x-ray ablation on the NOVA laser [J. L. Emmet, W. F. Krupkel and J. B. Trenholme, Sov, J, Quantum Electron. 13, 1 (1983)]. By doping sections of the cylinder with opaque materials, in conjunction with x-ray backlighting, the growth and feedthrough of the perturbations from the ablation front to the inner surface of the cylinder for various initial modes and amplitudes from early time through stagnation was measured, Mode coupling of illumination asymmetries with material perturbations is observed, as well as phase reversal of the perturbations from near the ablation front to the inner surface of the cylinder. Perturbation growth is observed due to convergence and compressibility alone, without the effects of acceleration, and scales as similar to 1/rho R, where rho is the mass density, Imaging is performed with an x-ray pinhole camera coupled to a gated microchannel plate detector. C1 CEA,LIMEIL VALENTON,FRANCE. ATOM WEAPONS ESTAB,ALDERMASTON,ENGLAND. RP Hsing, WW (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 31 TC 44 Z9 49 U1 2 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1832 EP 1840 DI 10.1063/1.872326 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700040 ER PT J AU Vu, HX AF Vu, HX TI Three-dimensional particle-in-cell simulations of ion-driven parametric instabilities SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID PLASMAS AB HERCULES, a massively parallel three-dimensional hybrid particle-in-cell (PIG) code, implemented on the CRAY-T3D, is presented. The code is based on a physical model, described in a previous report, where the electrons are modeled as an adiabatic fluid with an arbitrary ratio of specific heats gamma, and the electromagnetic field model is based on a temporal WKB approximation. On a CRAY-T3D with 512 processors, the code requires about 0.6 mu s/particle/time step. The largest test problem performed with this code consists of a computational mesh of 4096 x 64 x 64 (16 million) cells, and a total of 256 million particles, and corresponds to a plasma volume of 250 x mu m x 62.5 mu m x 62.5 mu m. This code is the first PIC code capable of simulating ion-driven parametric instabilities in a large plasma volume, and it offers a unique opportunity for examining issues that are potentially vital to inertial confinement fusion (ICF), e.g., nonlinear ion kinetic effects and their role in nonlinear saturation mechanisms. Applications of HERCULES in simulations of Gaussian f/4 diffraction-limited lasers with and without transverse plasma hows are presented. Simulation parameters are chosen to correspond to actual experimental conditions, and the simulations are performed over a substantial portion of the actual laser pulse. The simulations indicate that while the transmitted laser beam can be significantly deflected by transverse flows, the SBS-reflected beam does not necessarily exhibit the same behavior. Furthermore, the total SBS reflectivity appears to be insensitive to transverse flows. In the simulations, the late-time SBS reflectivity is 25%, which compares favorably to the 10%-20% range measured in actual experiments. The simulations in this paper are the first PIC simulations of ICF experiments in which both the temporal and spatial scales of the experiments are captured in their entireties. (C) 1997 American Institute of Physics. RP Vu, HX (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 11 TC 15 Z9 15 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1841 EP 1848 DI 10.1063/1.872327 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700041 ER PT J AU Fernandez, JC Bauer, BS Cobble, JA DuBois, DF Kyrala, GA Montgomery, DS Rose, HA Vu, HX Watt, RG Wilde, BH Wilke, MD Wood, MW Failor, BH Kirkwood, R MacGowan, BJ AF Fernandez, JC Bauer, BS Cobble, JA DuBois, DF Kyrala, GA Montgomery, DS Rose, HA Vu, HX Watt, RG Wilde, BH Wilke, MD Wood, MW Failor, BH Kirkwood, R MacGowan, BJ TI Measurements of laser-plasma instability relevant to ignition hohlraums SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID STIMULATED RAMAN-SCATTERING; INERTIAL CONFINEMENT FUSION; ION-ACOUSTIC-WAVES; BRILLOUIN-SCATTERING; HOT-SPOTS; SATURATION; FACILITY; LANGMUIR; SUPPRESSION; COMPETITION AB The potential for laser-plasma instability is a serious concern for indirect-drive inertial confinement fusion (ICF), where laser beams illuminate the interior of a cavity (called a hohlraum) to produce x-rays for imploding a fusion capsule symmetrically. The speckled nature of laser beams used in ICF is an important factor in laser-plasma instability processes. For example, models which calculate the spatial growth of convective instability by properly accounting for the laser speckles successfully predict the observed onsets of backscattering due to stimulated Brillouin and Raman scattering instabilities (SBS and SRS). Assuming pump depletion as the only saturation mechanism in these models results in very large predicted levels of SBS and SRS backscattering from the long-scale plasmas expected in ignition hohlraums. However, in the long-scale plasmas studied in the Nova and Trident lasers [E. M. Campbell, Rev. Sci. Instrum. 57, 2101 (1986) and N. K. Moncur et al., Appl. Opt. 34, 4274 (1995)], SRS and SBS are observed to saturate much below the levels expected from pump depletion. While the mechanism of SBS saturation is not understood at present, the observations of SRS saturation are qualitatively understood. (C) 1997 American Institute of Physics. C1 PHYS INT CO,SAN LEANDRO,CA 94577. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Fernandez, JC (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. RI Fernandez, Juan/H-3268-2011; OI Fernandez, Juan/0000-0002-1438-1815; Montgomery, David/0000-0002-2355-6242 NR 50 TC 37 Z9 38 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1849 EP 1856 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700042 ER PT J AU Cauble, R DaSilva, LB Perry, TS Bach, DR Budil, KS Celliers, P Collins, GW Ng, A Barbee, TW Hammel, BA Holmes, NC Kilkenny, JD Wallace, RJ Chiu, G Woolsey, NC AF Cauble, R DaSilva, LB Perry, TS Bach, DR Budil, KS Celliers, P Collins, GW Ng, A Barbee, TW Hammel, BA Holmes, NC Kilkenny, JD Wallace, RJ Chiu, G Woolsey, NC TI Absolute measurements of the equations of state of low-Z materials in the multi-Mbar regime using laser-driven shocks SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID MU-M WAVELENGTH; WAVE EXPERIMENTS; MOLECULAR-HYDROGEN; DENSE MATTER; RADIATION; COMPRESSION; PRESSURES; ALUMINUM; TPA; GBAR AB Although high intensity lasers offer the opportunity to explore the equations of state (EOSs) of materials under high energy density conditions, experimental difficulties have limited the application of laser-driven shocks to EOS measurements. However, we have recently performed absolute EOS measurements on the principal Hugoniot of liquid deuterium near one Mbar and of polystyrene from 10 to 40 Mbar. The D-2 measurements were made with direct drive; the polystyrene experiments were indirectly driven. The data were sufficiently accurate to differentiate between existing EOS models and were surprising, particularly for D-2. The results demonstrate that laser driven shocks can be used effectively to investigate high pressure EOSs. (C) 1997 American Institute of Physics. C1 UNIV BRITISH COLUMBIA,VANCOUVER,BC V5Z 1M9,CANADA. QUEENS UNIV BELFAST,BELFAST,ANTRIM,NORTH IRELAND. RP Cauble, R (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Perry, Theodore/K-3333-2014 OI Perry, Theodore/0000-0002-8832-2033 NR 39 TC 50 Z9 51 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1857 EP 1861 DI 10.1063/1.872362 PN 2 PG 5 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700043 ER PT J AU Amendt, P Glendinning, SG Hammel, BA Landen, OL Murphy, TJ Suter, LJ Hatchett, S Rosen, MD Lafitte, S Desenne, D Jadaud, JP AF Amendt, P Glendinning, SG Hammel, BA Landen, OL Murphy, TJ Suter, LJ Hatchett, S Rosen, MD Lafitte, S Desenne, D Jadaud, JP TI New methods for diagnosing and controlling hohlraum drive asymmetry on Nova SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID IGNITION; FACILITY; SYMMETRY; FUSION AB A novel method to control lowest-order(P-2) flux asymmetry in Nova cylindrical hohlraums [E, M. Campbell er al., Rev. Sci. Instrum. 57, 2101 (1986)] with fixed laser beams is to use a pair of axial gold disks of varying radii to partially block the capsule view of the laser-entrance holes. Some advantages in using axial disks include the prospect for added drive on target, the potential for P-4 control when used in tandem with laser pointing, and possibly reduced time-dependent P-2(t) flux asymmetry swings at early time. Neutron-based diagnostics have provided some suggestion of increased drive, but a more direct measure of drive enhancement is with the use of backlit, low-density (0.3 g/cc) foam surrogate targets. In this scheme, an ablatively driven, inwardly propagating shock is imaged in time using backlighting from an irradiated Ti disk placed outside of the hohlraum. The benefit in using low-density surrogate targets is an amplified shock speed that enables easier detection of both average shock motion (drive) and distortion (flux asymmetry. Experiments and calculations are in excellent agreement over a nearly 10% enhancement in peak drive temperature in the presence of axial gold disks. Measurements of lower-order distortion, P-2(t) and P-4(t), versus time for several laser pointings (without axial disks) using this technique have also been carried out and show good agreement between experiment and simulations. Efforts to further control time-dependent flux asymmetry using multiple ring, beam-phasing techniques on Nova. as will be required for the National Ignition Facility [J. Lindl. Phys. Plasmas 2, 3933 (1995)], are under development. Current designs indicate an appreciable reduction in P-2(t) is possible, Significant control of time-integrated P-4 flux asymmetry with appreciable inner and outer ring separation also appears possible. (C) 1997 American Institute of Physics. C1 CEA,CTR ETUD LIMEIL,LIMEIL VALENTON,FRANCE. RP Amendt, P (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Murphy, Thomas/F-3101-2014 OI Murphy, Thomas/0000-0002-6137-9873 NR 34 TC 19 Z9 20 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1862 EP 1871 DI 10.1063/1.872329 PN 2 PG 10 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700044 ER PT J AU Shvets, G Wurtele, JS Shadwick, BA AF Shvets, G Wurtele, JS Shadwick, BA TI Analysis and simulation of Raman backscatter in underdense plasmas SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID INTENSE LASER-PULSES; FREE-ELECTRON LASERS; STIMULATED RAMAN; SELF-MODULATION; SCATTERING; INSTABILITIES; PROPAGATION; SPECTRUM; TARGETS; DRIVEN AB A new formalism to describe the spatiotemporal evolution of relativistic Raman backscatter (RBS) of ultrashort laser pulses in underdense plasma has been developed. This theory is based on an eikonal representation for the RES field and averaging over the oscillation frequency. Equations are derived for the evolution of the RES radiation field amplitude and phase and for particle motion in the ponderomotive potential of the pump and RES fields. A technique similar to that used in Raman free electron lasers is used to include the plasma density oscillation and its electric field in the particle equations, The equations have been solved numerically in a code that provides an accurate description of the nonlinear electron motion on a short spatial scale of half the radiation wavelength while at the same time evolving the laser field on a much coarser scale, characteristic of the growth rate of the instability. Two-dimensional nonlinear effects, such as the return current. are analytically estimated and phenomenologically incorporated in the numerical code. The results of recent (RBS) experiments are compared with the analytical and numerical predictions of the theory, A statistical theory of the linear RES instability growing from plasma noise is developed. It is found that in the nonlinear regime backscattered radiation, seeded by random density fluctuations in the plasma, breaks up into spikes, which exhibit superradiant behavior. These effects might explain the spikiness of the RES spectra in the nonlinear regime. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94270. RP Shvets, G (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI wurtele, Jonathan/J-6278-2016 OI wurtele, Jonathan/0000-0001-8401-0297 NR 40 TC 38 Z9 38 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1872 EP 1880 DI 10.1063/1.872330 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700045 ER PT J AU Qian, Q Lee, WWL Davidson, RC AF Qian, Q Lee, WWL Davidson, RC TI Nonlinear delta f simulation studies of intense ion beam propagation through an alternating-gradient quadrupole focusing field SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID PARTICLE-SIMULATION AB Newly-developed perturbative (delta f) particle simulation techniques are used to investigate the detailed stability and transport properties of an intense ion beam propagating through an alternating-gradient focusing lattice with initial Kapchinskij-Vladimirskij (KV) distribution. Stability properties are investigated over a wide range of beam current and focusing field strength. In the unstable region, large-amplitude density perturbations with low azimuthal harmonic numbers, concentrated near the beam surface, are observed, and their nonlinear consequences are discussed. In the stable region, it is shown that the KV beam distribution propagates quiescently over large distances (up to 500 lattice periods in the simulations). The delta f-scheme used in the present numerical studies exhibits minimal noise and accuracy problems in comparison with standard particle-in-cell simulations. (C) 1997 American Institute of Physics. RP Qian, Q (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 24 TC 23 Z9 22 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1915 EP 1921 DI 10.1063/1.872557 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700050 ER PT J AU Tuszewski, M AF Tuszewski, M TI Inductive electron heating revisited SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID COUPLED PLASMA SOURCES; MODEL; SIMULATION; DISCHARGE; DENSITY; FIELDS AB The induced of magnetic fields of low-frequency inductively coupled plasmas are measured and modeled [M, Tuszewski, Phys. Rev. Lett. 77, 1286 (1996)]. The fields penetrate deep into the discharges, in contrast with existing predictions of field decay within a thin skin layer. Fluid calculations suggest that the enhanced of penetration is due to a reduction of the plasma conductivity by the induced magnetic fields. In this paper, new oxygen and argon data concerning of power are reported and a general description of inductive electron heating is suggested. (C) 1997 American Institute of Physics. RP Tuszewski, M (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 33 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1922 EP 1928 DI 10.1063/1.872335 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700051 ER PT J AU Yamada, M Ji, HT Hsu, S Carter, T Kulsrud, R Bretz, N Jobes, F Ono, Y Perkins, F AF Yamada, M Ji, HT Hsu, S Carter, T Kulsrud, R Bretz, N Jobes, F Ono, Y Perkins, F TI Study of driven magnetic reconnection in a laboratory plasma SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID LINE RECONNECTION; DAYSIDE MAGNETOPAUSE; CURRENT SHEETS; FIELD; TOKAMAK; ATMOSPHERE; SPHEROMAK; LAYERS; PROBE; FLUX AB The magnetic reconnection experiment has been constructed to investigate the fundamental physics of magnetic reconnection in a well-controlled laboratory setting, This device creates an environment satisfying the criteria for a magnetohydrodynamic plasma (S much greater than 1, (rho i) much less than L) The boundary conditions can be controlled externally, and experiments with fully three-dimensional reconnection are now possible. In the initial experiments, the effects of the third vector component of reconnecting fields have been studied, Two distinctively different shapes of neutral sheet current layers, depending on the third component, are identified during driven magnetic reconnection. Without the third component (antiparallel or null-helicity reconnection), a thin double-Y-shaped diffusion region is identified, A neutral sheet current profile is measured accurately to be as narrow as the order of the ion gyroradius. In the presence of an appreciable third component (co-helicity reconnection), an O-shaped diffusion region appears and grows into a spheromak configuration. (C) 1997 American Institute of Physics. RP Yamada, M (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Carter, Troy/E-7090-2010; Yamada, Masaaki/D-7824-2015 OI Carter, Troy/0000-0002-5741-0495; Yamada, Masaaki/0000-0003-4996-1649 NR 47 TC 161 Z9 165 U1 0 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1936 EP 1944 DI 10.1063/1.872336 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700053 ER PT J AU Weber, SV Glendinning, SG Kalantar, DH Key, MH Remington, BA Rothenberg, JE Wolfrum, E Verdon, CP Knauer, JP AF Weber, SV Glendinning, SG Kalantar, DH Key, MH Remington, BA Rothenberg, JE Wolfrum, E Verdon, CP Knauer, JP TI Simulations of laser imprint for Nova experiments and for ignition capsules SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID RAYLEIGH-TAYLOR INSTABILITY; INDUCED SPATIAL INCOHERENCE; FACILITY; TARGETS; PLASMA; FUSION; GROWTH; BEAM; OPACITY AB In diner drive inertial confinement fusion (ICF), nonuniformities in laser illumination seed ripples at the ablation front in a process called ''imprint.'' These nonuniformities grow during the capsule implosion and, if initially large enough, can penetrate the capsule shell, impede ignition, or degrade burn. Imprint has been simulated for recent experiments performed on the Nova laser [Campbell rt nl., Rev. Sci. Instrum. 57, 2101 (1986)] examining a variety of beam smoothing conditions. Most used laser intensities similar to the early part of an ignition capsule pulse shape, I similar or equal to 10(13) W/cm(2). The simulations matched most of the measurements of imprint modulation. The effect of imprint upon National ignition Facility (NIF) direct drive ignition capsules has also been simulated. Imprint is predicted to give modulation comparable to an intrinsic surface finish of similar to 10 nm rms. Modulation growth was examined using the Haan [Phys, Rev. A 39, 5512 (1989)] model, with linear growth factors as a function of spherical harmonic mode number obtained from an analytic dispersion relation. Ablation front amplitudes are predicted to become substantially nonlinear, so that saturation corrections are large. Direct numerical simulations of two-dimensional multimode growth were also pet formed. The capsule shell is predicted to remain intact, which fives a basis for believing that ignition can be achieved. (C) 1997 American Institute of Physics. C1 RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14623. RP Weber, SV (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 38 TC 34 Z9 34 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1978 EP 1984 DI 10.1063/1.872339 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700058 ER PT J AU Kalantar, DH Key, MH DaSilva, LB Glendinning, SG Remington, BA Rothenberg, JE Weber, F Weber, SV Wolfrum, E Kim, NS Neely, D Zhang, J Wark, JS Demir, A Lin, J Smith, R Tallents, GJ Lewis, CLS MacPhee, A Warwick, J Knauer, JP AF Kalantar, DH Key, MH DaSilva, LB Glendinning, SG Remington, BA Rothenberg, JE Weber, F Weber, SV Wolfrum, E Kim, NS Neely, D Zhang, J Wark, JS Demir, A Lin, J Smith, R Tallents, GJ Lewis, CLS MacPhee, A Warwick, J Knauer, JP TI Measurements of direct drive laser imprint in thin foils by radiography using an x-ray laser backlighter SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID INDUCED SPATIAL INCOHERENCE; INSTABILITY; UNIFORMITY; FACILITY; TARGETS; OPACITY; FUSION; BEAM AB In direct drive inertial confinement fusion, the residual speckle pattern remaining after beam smoothing plays an important role in the seeding of instabilities at the ablation front. An x-ray laser is used as an extreme ultraviolet backlighter to characterize the imprinted modulation in thin foils for smoothing by random phase plate and by spectral dispersion for both 0.35 and 0.53 mu m irradiation, and by induced spatial incoherence for 0.53 mu m irradiation. Measurements of the imprinted modulation due to a single optical mode generated by two beam interference, and modification of the imprint with a superposed smooth irradiation to study time dependence of the imprinting process are demonstrated. (C) 1997 American Institute of Physics. C1 RUTHERFORD APPLETON LAB,CENT LASER FACIL,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV OXFORD,CLARENDON LAB,OXFORD OX1 3PU,ENGLAND. UNIV ESSEX,DEPT PHYS,COLCHESTER,ESSEX,ENGLAND. QUEENS UNIV BELFAST,DEPT PURE & APPL PHYS,BELFAST,ANTRIM,NORTH IRELAND. RP Kalantar, DH (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. RI Zhang, Jie/O-8767-2014 NR 31 TC 26 Z9 26 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1985 EP 1993 DI 10.1063/1.872340 PN 2 PG 9 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700059 ER PT J AU Remington, BA Kane, J Drake, RP Glendinning, SG Estabrook, K London, R Castor, J Wallace, RJ Arnett, D Liang, E McCray, R Rubenchik, A Fryxell, B AF Remington, BA Kane, J Drake, RP Glendinning, SG Estabrook, K London, R Castor, J Wallace, RJ Arnett, D Liang, E McCray, R Rubenchik, A Fryxell, B TI Supernova hydrodynamics experiments on the Nova laser SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID RAYLEIGH-TAYLOR INSTABILITIES; LARGE MAGELLANIC CLOUD; HELIUM STAR MODELS; SINGLE-MODE; SN 1987A; POSTEXPLOSION HYDRODYNAMICS; IB/IC SUPERNOVAE; HUBBLE CONSTANT; LINE-PROFILES; II SUPERNOVAE AB In studying complex astrophysical phenomena such as supernovae, one does not have the luxury of setting up clean, well-controlled experiments in the universe to test the physics of current models and theories. Consequently, creating a surrogate environment to serve as an experimental astrophysics testbed would be highly beneficial. The existence of highly sophisticated, modern research lasers, developed largely as a result of the world-wide effort in inertial confinement fusion, opens a new potential for creating just such an experimental testbed utilizing well-controlled, well-diagnosed laser-produced plasmas, Two areas of physics critical to an understanding of supernovae are discussed that are amenable to supporting research on large lasers: (1) compressible nonlinear hydrodynamic mixing and (2) radiative shock hydrodynamics. (C) 1997 American Institute of Physics. C1 UNIV ARIZONA, TUCSON, AZ 85721 USA. UNIV MICHIGAN, ANN ARBOR, MI 48109 USA. RICE UNIV, HOUSTON, TX 77251 USA. UNIV COLORADO, BOULDER, CO 80309 USA. UNIV CALIF DAVIS, DAVIS, CA 95616 USA. GEORGE MASON UNIV, FAIRFAX, VA 22030 USA. RP Remington, BA (reprint author), LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 86 TC 104 Z9 107 U1 2 U2 13 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 1994 EP 2003 DI 10.1063/1.872341 PN 2 PG 10 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700060 ER PT J AU Wark, JS Rose, SJ Patel, PK Djaoui, A Renner, O Hauer, A AF Wark, JS Rose, SJ Patel, PK Djaoui, A Renner, O Hauer, A TI Astrophysically relevant experiments on radiation transfer through plasmas with large velocity gradients SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 38th Annual Meeting of the Division-of-Plasma-Physics of the American-Physical-Society CY NOV 11-15, 1996 CL DENVER, CO SP Amer Phys Soc, Div Plasma Phys ID LASER-PRODUCED PLASMAS; LINE TRANSFER; EXPANDING ATMOSPHERES; ESCAPE PROBABILITY; SPECTROSCOPY; MEDIA; OPACITY; GAIN AB The transfer of radiation through plasmas with large velocity gradients is of relevance to several astrophysical situations, such as supernova explosions, maser operation, and stellar winds. Similar conditions often prevail in laser-produced plasmas, with velocity gradients of order 10(9) s(-1) significantly altering the effective optical depth and line shape. Some of the simplest cases to study experimentally are the hydrogenic resonance lines. Experiments performed in both planar and cylindrical geometry, comparing the observed line profiles with those modeled using a one-dimensional Lagrangian hydrocode, incorporating average-atom nonlocal thermodynamic equilibrium (non-LTE) atomic physics are described. The opacity effects on the ion populations an treated within the escape factor approximation, taking into account the effects of the velocity gradient. The hydrocode gives time- and space-dependent values of the electron and ion densities, excited state fractions, electron and ion temperatures, and velocities, The hydrodynamic output is post-processed with a radiative transfer routine to construct the simulated line shape. Details of the experiments and results are presented, and relevance to the astrophysical situations discussed. (C) 1997 American Institute of Physics. C1 RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. ACAD SCI CZECH REPUBL,INST PHYS,CZ-18040 PRAGUE,CZECH REPUBLIC. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Wark, JS (reprint author), UNIV OXFORD,DEPT PHYS,CLARENDON LAB,PARKS RD,OXFORD OX1 3PU,ENGLAND. RI Patel, Pravesh/E-1400-2011; Renner, Oldrich/C-1591-2010; OI Renner, Oldrich/0000-0003-4942-2637; Rose, Steven/0000-0001-6808-6355 NR 36 TC 16 Z9 16 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1997 VL 4 IS 5 BP 2004 EP 2010 DI 10.1063/1.872342 PN 2 PG 7 WC Physics, Fluids & Plasmas SC Physics GA WY647 UT WOS:A1997WY64700061 ER PT J AU Schmidt, JA Davidson, RC Holt, RD AF Schmidt, JA Davidson, RC Holt, RD TI Development of fusion power seen as essential to world's energy future; Critics respond SO PHYSICS TODAY LA English DT Letter RP Schmidt, JA (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, 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 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1997 VL 50 IS 5 BP 11 EP & DI 10.1063/1.881611 PG 2 WC Physics, Multidisciplinary SC Physics GA WX105 UT WOS:A1997WX10500001 ER PT J AU Najmabadi, F Tillack, M Waganer, L Jardin, S Wong, C Sze, DK ElGuebaly, L Bromberg, L AF Najmabadi, F Tillack, M Waganer, L Jardin, S Wong, C Sze, DK ElGuebaly, L Bromberg, L TI Development of fusion power seen as essential to world's energy future; Critics respond SO PHYSICS TODAY LA English DT Letter C1 MCDONNELL DOUGLAS CORP,ST LOUIS,MO 63166. PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. GEN ATOM CO,SAN DIEGO,CA. ARGONNE NATL LAB,BATAVIA,IL. UNIV WISCONSIN,MADISON,WI. MIT,CAMBRIDGE,MA 02139. RP Najmabadi, F (reprint author), UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093, USA. RI Jardin, Stephen/E-9392-2010 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1997 VL 50 IS 5 BP 13 EP & PG 2 WC Physics, Multidisciplinary SC Physics GA WX105 UT WOS:A1997WX10500002 ER PT J AU Perkins, LJ AF Perkins, LJ TI Development of fusion power seen as essential to world's energy future; Critics respond SO PHYSICS TODAY LA English DT Letter RP Perkins, LJ (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 6 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 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1997 VL 50 IS 5 BP 15 EP & PG 2 WC Physics, Multidisciplinary SC Physics GA WX105 UT WOS:A1997WX10500003 ER PT J AU Symon, KR Huber, DL Trzeciak, WS Mills, FE Weaver, JH AF Symon, KR Huber, DL Trzeciak, WS Mills, FE Weaver, JH TI Ednor Marsh Rowe - Obituary SO PHYSICS TODAY LA English DT Item About an Individual C1 FERMILAB ASTROPHYS CTR,BATAVIA,IL. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. RP Symon, KR (reprint author), UNIV WISCONSIN,MADISON,WI 53706, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1997 VL 50 IS 5 BP 78 EP 79 DI 10.1063/1.2806664 PG 2 WC Physics, Multidisciplinary SC Physics GA WX105 UT WOS:A1997WX10500022 ER PT J AU Lipschutz, ME Wolf, SF Dodd, RT AF Lipschutz, ME Wolf, SF Dodd, RT TI Meteoroid streams as sources for meteorite falls: A status report SO PLANETARY AND SPACE SCIENCE LA English DT Article ID NON-ANTARCTIC METEORITES; H-CHONDRITES; PARENT BODY; TRACE-ELEMENTS; BREAKUP; EARTH; POPULATIONS; AGES AB From their circumstances of fall (year, day, and, sometimes, petrographic type) five clusters of H4-6 chondrites have been identified statistically as deriving from separate meteoroid streams. Using another criterion the meteorites' contents of volatile trace elements (Ag, Bi, Cd, Cs, In, Rb, Se, Te, Tl, Zn) determined using radiochemical neutron activation analysis, and treated by multivariate statistical analysis techniques, three of the five clusters are distinguishable from the random background of observed falls. These data indicate that distinct H chondrite sources with primary thermal histories distinguishable from those of random sources provided H4-6 chondrites that fell in May, 1855-1895, and in September-October, 1812-1992. Thus, both in the short-term, and the long-term (> 50 kyr) as evidenced by Antarctic H4-6 chondrites, time-dependent variations occur in the Earth's sampling of common meteorites. The source-variations indicated by our data apparently reflect the existence of meteoroid streams which complete the hierarchy of comet steams, asteroid streams and fireball streams of asteroidal origin established by others. (C) 1997 Published by Elsevier Science Ltd. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. SUNY STONY BROOK,DEPT EARTH & SPACE SCI,STONY BROOK,NY 11794. RP Lipschutz, ME (reprint author), PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907, USA. NR 39 TC 8 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 1997 VL 45 IS 5 BP 517 EP 523 DI 10.1016/S0032-0633(96)00148-1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XH882 UT WOS:A1997XH88200001 ER PT J AU Hills, JG Goda, MP AF Hills, JG Goda, MP TI Meteoroids captured into Earth orbit by grazing atmospheric encounters SO PLANETARY AND SPACE SCIENCE LA English DT Article AB Some meteoroids, such as the one that produced the daytime fireball of August 10, 1972 that passed over the western United States and the European fireball of October 13, 1990, graze the atmosphere of Earth before returning to space (at reduced speed). Other grazing meteoroids, such as Peekskill, penetrate deeper into the atmosphere and lose enough energy to plunge to ground. It is evident that if a grazing meteoroid is within some critical range of closest approach distance and speed, it is captured into a gravitationally bound orbit around Earth. It must ultimately plunge to ground after further orbital dissipation in subsequent atmospheric passages unless the gravitational pull of the Moon and Sun or other intervention raise its perigee above the atmosphere. A spherical atmospheric model is used to integrate the passage of meteoroids in grazing atmospheric encounters. It is found that the corridor for capture narrows with increasing values of V-infinity, the approach velocity of the meteoroid prior to gravitational acceleration by Earth. As an example, if V-infinity = 5 km s(-1), stony meteoroids with closest-approach distances of h = 40 km above the Earth are captured if their radii, R, are between 3 and 9 m while if V-infinity = 15 km s(-1) and h = 40 km, they are only captured if R is between 1.5 and 2 m. Irons with V-infinity = 5 km s(-1) and h = 40 km, are captured if R is between 1 and 3.5 m, while if V-infinity = 15 km s(-1), they are captured if R is between 0.6 and 0.9 m. The cross section for orbital capture of iron meteoroids and small stony meteoroids is about 0.001 that for directly hitting Earth. Large stones are never captured except at very low impact velocities because of the large increase in drag resulting from fragmentation. Published by Elsevier Science Ltd. RP Hills, JG (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,THEORET ASTROPHYS GRP,T-6,M-S B288,LOS ALAMOS,NM 87545, USA. NR 8 TC 6 Z9 6 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAY PY 1997 VL 45 IS 5 BP 595 EP 602 DI 10.1016/S0032-0633(97)00039-1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA XH882 UT WOS:A1997XH88200010 ER PT J AU Osborne, CP Drake, BG LaRoche, J Long, SP AF Osborne, CP Drake, BG LaRoche, J Long, SP TI Does long-term elevation of CO2 concentration increase photosynthesis in forest floor vegetation? Indiana strawberry in a Maryland forest SO PLANT PHYSIOLOGY LA English DT Article ID VASCULAR PLANTS; ATMOSPHERIC CO2; CARBON-DIOXIDE; QUANTUM YIELD; ACCLIMATION; GROWTH; EXPRESSION; NITROGEN; PROTEINS; RUBISCO AB As the partial pressure of CO2 (pCO(2)) in the atmosphere rises, photorespiratory loss of carbon in C-3 photosynthesis will diminish and the net efficiency of light-limited photosynthetic carbon uptake should rise. We tested this expectation for Indiana strawberry (Duchesnea indica) growing on a Maryland forest floor. Open-top chambers were used to elevate the pCO(2) of a forest floor habitat to 67 Pa and were paired with control chambers providing an ambient pCO(2) of 38 Pa. After 3.5 years, D. indica leaves grown and measured in the elevated pCO(2) showed a significantly greater maximum quantum efficiency of net photosynthesis (by 22%) and a lower light compensation point (by 42%) than leaves grown and measured in the control chambers. The quantum efficiency to minimize photorespiration, measured in 1% O-2, was the same for controls and plants grown at elevated pCO(2). This showed that the maximum efficiency of light-energy transduction into assimilated carbon was not altered by acclimation and that the increase in light-limited photosynthesis at elevated pCO(2) was simply a function of the decrease in photorespiration. Acclimation did decrease the ribulose-1,5-bisphosphate carboxylase/oxygenase and light-harvesting chlorophyll protein content of the Leaf by more than 30%. These changes were associated with a decreased capacity for light-saturated, but not light-limited, photosynthesis. Even so, leaves of D. indica grown and measured at elevated pCO(2) showed greater light-saturated photosynthetic rates than leaves grown and measured at the current atmospheric pCO(2). In situ measurements under natural forest floor lighting showed large increases in leaf photosynthesis at elevated pCO(2), relative to controls, in both summer and fall. The increase in efficiency of light-limited photosynthesis with elevated pCO(2) allowed positive net photosynthetic carbon uptake on days and at locations on the forest floor that light fluxes were insufficient for positive net photosynthesis in the current atmospheric pCO(2). C1 UNIV ESSEX, JOHN TABOR LABS, DEPT SCI BIOL, COLCHESTER CO4 3SQ, ESSEX, ENGLAND. SMITHSONIAN ENVIRONM RES CTR, EDGEWATER, MD 21037 USA. BROOKHAVEN NATL LAB, DEPT APPL SCI, UPTON, NY 11973 USA. RI Long, Stephen/A-2488-2008; LaRoche, Julie/A-1109-2010 OI Long, Stephen/0000-0002-8501-7164; NR 33 TC 56 Z9 64 U1 0 U2 7 PU AMER SOC PLANT BIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA SN 0032-0889 EI 1532-2548 J9 PLANT PHYSIOL JI Plant Physiol. PD MAY PY 1997 VL 114 IS 1 BP 337 EP 344 PG 8 WC Plant Sciences SC Plant Sciences GA WY998 UT WOS:A1997WY99800038 ER PT J AU Baldis, HA Labaune, C AF Baldis, HA Labaune, C TI Interplay between parametric instabilities in the context of inertial confinement fusion SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT International Conference on Plasma Physics CY SEP 09-13, 1996 CL NAGOYA, JAPAN ID STIMULATED RAMAN-SCATTERING; LASER-PRODUCED PLASMA; BRILLOUIN-SCATTERING; LANGMUIR; SUPPRESSION; SATURATION AB This paper presents recent experimental results that clearly demonstrate the complex interplay between parametric instabilities in a laser-produced plasma. These results include: (a) the interplay between ion acoustic waves (IAW) and electron plasma waves (EPW) associated with stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS), (b) the interplay between IAW from two independent SBS decays when two interaction beams are present and (c) the observation of a secondary process, the Langmuir decay instability (LDI), which is the further decay of EPWs driven by SRS, into an IAW and a secondary EPW. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. RP Baldis, HA (reprint author), ECOLE POLYTECH,CNRS,LAB UTILISAT LASERS INTENSES,F-91128 PALAISEAU,FRANCE. NR 16 TC 6 Z9 6 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 1997 VL 39 IS 5A SI SI BP 51 EP 57 DI 10.1088/0741-3335/39/5A/006 PG 7 WC Physics, Fluids & Plasmas SC Physics GA XD875 UT WOS:A1997XD87500006 ER PT J AU Kruer, WL AF Kruer, WL TI Deflection, spraying and induced scattering of intense laser beams in plasmas SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT International Conference on Plasma Physics CY SEP 09-13, 1996 CL NAGOYA, JAPAN ID STIMULATED RAMAN-SCATTERING; ION-ACOUSTIC-WAVES; FILAMENTATION; LANGMUIR; SATURATION; DECAY AB Investigations into laser beam spraying, deflection and induced scattering in plasmas are presented. Recent calculations and experiments on beam spraying due to filamentation are discussed. A simple model is presented for an enhanced beam deflection associated with nearly sonic plasma flow transverse to the beam. This model provides useful insights on the laser beam deflection, its scaling and the importance of self-consistent profile modifications. Finally, some discussion is given of recent experiments demonstrating the interplay between stimulated Raman and Brillouin scattering. RP Kruer, WL (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-472,LIVERMORE,CA 94551, USA. NR 34 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 1997 VL 39 IS 5A SI SI BP 153 EP 159 DI 10.1088/0741-3335/39/5A/016 PG 7 WC Physics, Fluids & Plasmas SC Physics GA XD875 UT WOS:A1997XD87500016 ER PT J AU Zweben, SJ Arunasalam, V Batha, SH Budny, RV Bush, CE Cauffman, S Chang, CS Chang, Z Cheng, CZ Darrow, DS Dendy, RO Duong, HH Fisch, NJ Fredrickson, ED Fisher, RK Fonck, RJ Fu, GY Goloborodko, V Gorelenkov, N Hawryluk, RJ Heeter, R Heidbrink, WW Herrmann, HW Herrmann, M Johnson, DW Machuzak, J Majeski, R McGuire, KM McKee, G Medley, SS Mynick, HE Nazikian, R Petrov, MP Redi, MH Reznik, S Rogers, J Schilling, G Spong, DA Strachan, JD Stratton, BC Synakowski, E Taylor, G Wang, S White, RB Wong, KL Yavorski, V AF Zweben, SJ Arunasalam, V Batha, SH Budny, RV Bush, CE Cauffman, S Chang, CS Chang, Z Cheng, CZ Darrow, DS Dendy, RO Duong, HH Fisch, NJ Fredrickson, ED Fisher, RK Fonck, RJ Fu, GY Goloborodko, V Gorelenkov, N Hawryluk, RJ Heeter, R Heidbrink, WW Herrmann, HW Herrmann, M Johnson, DW Machuzak, J Majeski, R McGuire, KM McKee, G Medley, SS Mynick, HE Nazikian, R Petrov, MP Redi, MH Reznik, S Rogers, J Schilling, G Spong, DA Strachan, JD Stratton, BC Synakowski, E Taylor, G Wang, S White, RB Wong, KL Yavorski, V TI Alpha-particle physics in the tokamak fusion test reactor DT experiment SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT International Conference on Plasma Physics CY SEP 09-13, 1996 CL NAGOYA, JAPAN ID TFTR; DEUTERIUM; TRITIUM; DIFFUSION; IONS AB A summary is presented of recent alpha-particle experiments on the tokamak fusion test reactor. Alpha particles are generally well confined in MHD-quiescent discharges, and alpha heating of electrons has been observed. The theoretically predicted toroidicity-induced Alfven eigenmode has been seen in discharges of less than or equal to 1 MW of alpha power, but only in plasmas with weak magnetic shear. C1 FUS PHYS & TECHNOL,TORRANCE,CA 90503. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NYU,COURANT INST,NEW YORK,NY 10012. UKAEA,EURATOM,ABINGDON OX14 3DB,OXON,ENGLAND. GEN ATOM CO,SAN DIEGO,CA 92186. UNIV WISCONSIN,MADISON,WI 53706. INST NUCL RES,KIEV,UKRAINE. TRINITI,MOSCOW,RUSSIA. UNIV CALIF IRVINE,IRVINE,CA 92717. MIT,CAMBRIDGE,MA 02139. IOFFE INST,ST PETERSBURG,RUSSIA. ACAD SINICA,INST PLASMA PHYS,HEFEI 230031,PEOPLES R CHINA. RP Zweben, SJ (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Spong, Donald/C-6887-2012; Dendy, Richard/A-4533-2009; White, Roscoe/D-1773-2013; Cheng, Chio/K-1005-2014; Wang, Shaojie/A-2675-2017 OI Spong, Donald/0000-0003-2370-1873; White, Roscoe/0000-0002-4239-2685; Wang, Shaojie/0000-0002-2786-519X NR 32 TC 11 Z9 11 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 1997 VL 39 IS 5A SI SI BP 275 EP 283 PG 9 WC Physics, Fluids & Plasmas SC Physics GA XD875 UT WOS:A1997XD87500025 ER PT J AU West, WP Allen, SL Brooks, NH Buchenauer, DA Carlstrom, TN Cuthbertson, JW Doyle, EJ Evans, TE Fenstermacher, ME Hill, DN Hyatt, AW Isler, RC Jackson, GL Jong, R Klepper, CC Lasnier, CJ Leonard, AW Mahdavi, MA Maingi, R McKee, GR Meyer, WH Moyer, RA Nilson, DG Petrie, TW Porter, GD Rhodes, TL Schaffer, MJ Stambaugh, RD Thomas, DM Tugarinov, S Wade, MR Watkins, JG Whyte, DG Wood, RD AF West, WP Allen, SL Brooks, NH Buchenauer, DA Carlstrom, TN Cuthbertson, JW Doyle, EJ Evans, TE Fenstermacher, ME Hill, DN Hyatt, AW Isler, RC Jackson, GL Jong, R Klepper, CC Lasnier, CJ Leonard, AW Mahdavi, MA Maingi, R McKee, GR Meyer, WH Moyer, RA Nilson, DG Petrie, TW Porter, GD Rhodes, TL Schaffer, MJ Stambaugh, RD Thomas, DM Tugarinov, S Wade, MR Watkins, JG Whyte, DG Wood, RD TI Divertor plasma studies on DIII-D: Experiment and modelling SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT International Conference on Plasma Physics CY SEP 09-13, 1996 CL NAGOYA, JAPAN ID H-MODE DISCHARGES; ASDEX UPGRADE; TOKAMAK; CONFINEMENT; EXHAUST; REDUCTION; TRANSPORT AB In a magnetically diverted tokamak, the scrape-off layer (SOL) and divertor plasma separates the first wall from the core plasma, intercepting impurities generated at the wall before they reach the core plasma. The divertor plasma can also,serve to spread the heat and particle flux over a large area of divertor structure wall using impurity radiation and neutral charge exchange, thus reducing peak heat and particle fluxes at the divertor strike plate. Such a reduction will be required in the next generation of tokamaks, for without it the divertor engineering requirements are very demanding. To successfully demonstrate a radiative divertor, a highly radiative condition with significant volume recombination must be achieved in the divertor, while maintaining a low impurity content in the core plasma. Divertor plasma properties are determined by a complex interaction of classical parallel transport, anomalous perpendicular transport, impurity transport and radiation, and plasma-wall interaction. In this paper we will describe a set of experiments on DIII-D designed to provide detailed two-dimensional documentation of the divertor and SOL plasma. Measurements have been made in operating modes where the plasma is attached to the divertor strike plate and in highly radiating cases where the plasma is detached from the divertor strike plate. We will also discuss the results of experiments designed to influence the distribution of impurities in the plasma using enhanced SOL plasma flow. Extensive modelling efforts will be described which are successfully reproducing attached plasma conditions and are helping to elucidate the important plasma and atomic physics involved in the detachment process. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. SANDIA NATL LABS,LIVERMORE,CA. UNIV CALIF SAN DIEGO,SAN DIEGO,CA 92103. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. OAK RIDGE NATL LAB,OAK RIDGE,TN. OAK RIDGE ASSOCIATED UNIV,OAK RIDGE,TN. TRINITI LAB,TROITSK,MOSCOW REGION,RUSSIA. INRS ENERGIE,VARENNES,PQ J3X 1S2,CANADA. RP West, WP (reprint author), GEN ATOM CO,POB 85608,SAN DIEGO,CA 92186, USA. NR 33 TC 7 Z9 7 U1 2 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 1997 VL 39 IS 5A SI SI BP 295 EP 310 PG 16 WC Physics, Fluids & Plasmas SC Physics GA XD875 UT WOS:A1997XD87500027 ER PT J AU Ono, M Bell, R Choe, W Chang, CS Forest, CB Goldston, R Hwang, YS Jardin, SC Kaita, R Kaye, S Kessel, CE Kugel, H LeBlanc, B Manickam, J Menard, JE Munsat, T Okabayashi, M Peng, M Sesnic, S Tighe, W AF Ono, M Bell, R Choe, W Chang, CS Forest, CB Goldston, R Hwang, YS Jardin, SC Kaita, R Kaye, S Kessel, CE Kugel, H LeBlanc, B Manickam, J Menard, JE Munsat, T Okabayashi, M Peng, M Sesnic, S Tighe, W TI Plasma transport control and self-sustaining fusion reactor SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT International Conference on Plasma Physics CY SEP 09-13, 1996 CL NAGOYA, JAPAN ID POLOIDAL ROTATION; EDGE TURBULENCE; TOKAMAK; MODE; CONFINEMENT; TRANSITION; SHEAR AB The possibility of a high-performance/low-cost fusion reactor concept which can simultaneously satisfy (1) high beta, (2) high bootstrap fractio (self-sustaining) and (3) high confinement is discussed. In CDX-U, a tokamak configuration was created and sustained solely by internally generated bootstrap currents, in which a 'seed' current is created through a nonclassical current diffusion process. Recent theoretical studies of MHD stability limits in spherical tori [e.g. the National Spherical Torus Experiment (NSTX)] produced a promising regime with stable beta of 45% and bootstrap current fraction of greater than or equal to 99%. Since the bootstrap current is generated by the pressure gradient, to satisfy the needed current profile for MHD stable high beta regimes, it is essential to develop a means to control the pressure profile. It is suggested that the most efficient approach for pressure profile control is through the creation of transport barriers (localized regions of low plasma transport) in the plasma As a tool for creating the core transport barrier, poloidal-sheared-flow generation by ion Bernstein waves (IBW) near the wave absorption region appears to be promising. In PBX-M, application of IBW power produced a high-quality internal transport barrier where the ion energy and particle transport became neoclassical in the barrier region. The observation is consistent with the IBW-inducedpoloidal-sheared-flow model. An experiment is planned on TFTR to demonstrate this concept with D-T reactor-grade plasmas. For edge transport control, a method based on electron ripple injection (ERI), driven by electron cyclotron heating (ECH), is being developed on CDX-U. It is estimated that both the IBW and ERI methods can create a transport barrier in reactor-grade plasmas (e.g. ITER) with a relatively small amount of power (approximate to 10 MW much less than P-fusion). RP Ono, M (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Jardin, Stephen/E-9392-2010; Choe, Wonho/C-1556-2011; Hwang, Yong-Seok/D-8347-2012 NR 26 TC 6 Z9 6 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 1997 VL 39 IS 5A SI SI BP 361 EP 369 DI 10.1088/0741-3335/39/5A/033 PG 9 WC Physics, Fluids & Plasmas SC Physics GA XD875 UT WOS:A1997XD87500033 ER PT J AU Ozeki, T Azumi, M Ishii, Y Kishimoto, Y Fu, GY Fujita, T Rewoldt, G Kikuchi, M Kamada, Y Kimura, H Kusama, Y Saigusa, M Ide, S Shirai, H AF Ozeki, T Azumi, M Ishii, Y Kishimoto, Y Fu, GY Fujita, T Rewoldt, G Kikuchi, M Kamada, Y Kimura, H Kusama, Y Saigusa, M Ide, S Shirai, H TI Physics issues of high bootstrap current tokamaks SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article; Proceedings Paper CT International Conference on Plasma Physics CY SEP 09-13, 1996 CL NAGOYA, JAPAN ID REVERSED MAGNETIC SHEAR; IDEAL MHD STABILITY; ENHANCED CONFINEMENT; PLASMAS AB Physics issues of a tokamak plasma with a hollow current profile produced by a large bootstrap current are discussed based on experiments in JT-60U. An internal transport barrier for both ions and electrons was obtained just inside the radius of zero magnetic shear in JT-60U. Analysis of the toroidal ITG microinstability by toroidal particle simulation shows that weak and negative shear reduces the toroidal coupling and suppresses the ITG mode. A hard beta limit was observed in JT-60U negative shear experiments. Ideal MHD mode analysis shows that the n = 1 pressure-driven kink mode is a plausible candidate. One of the methods to improve the beta limit against the kink mode is to widen the negative shear region, which can induce a broader pressure profile resulting in a higher beta limit. The TAE mode for the hollow current profile is less unstable than that for the monotonic current profile. The reason is that the continuum gaps near the zero shear region are not aligned when the radius of q(min) is close to the region of high del n(c). Finally, a method for stable start-up for a plasma with a hollow current profile is described, and stable sustainment of a steady-state plasma with high bootstrap current is discussed. C1 PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Ozeki, T (reprint author), JAPAN ATOM ENERGY RES INST,NAKA FUS RES ESTAB,NAKA,IBARAKI 31101,JAPAN. RI Kikuchi, Mitsuru/O-1036-2015 OI Kikuchi, Mitsuru/0000-0002-5485-8737 NR 21 TC 4 Z9 4 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAY PY 1997 VL 39 IS 5A SI SI BP 371 EP 380 PG 10 WC Physics, Fluids & Plasmas SC Physics GA XD875 UT WOS:A1997XD87500034 ER PT J AU Veerasingam, R Campbell, RB McGrath, RT AF Veerasingam, R Campbell, RB McGrath, RT TI One-dimensional fluid simulations of a helium-xenon filled ac colour plasma flat panel display pixel SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article; Proceedings Paper CT Europhysics Sectional Conference on Atomic and Molecular Physics of Ionized Gases CY AUG 27-30, 1996 CL POPRAD, SLOVAKIA ID CELL; DISCHARGE; MODEL AB One-dimensional (1D) fluid simulations are used to model a helium-xenon filled ac plasma display pixel. The model includes four levels for helium atomic states, seven levels for xenon atomic states and a xenon dimer state. The model also includes VUV emission including photon trapping due to collisional broadening from the resonant atomic xenon at wavelengths of 129 nm and 147 nm and from non-resonant emission by the xenon dimer molecule peaked at 173 nm. Simulations are performed for a gap width (d) of 100 microns at a pressure (P) of 400 Torr using varying xenon concentrations. At low xenon concentrations, emission is primarily in the 147 nm wavelength but shifts toward the xenon dimer above about 20% xenon in the mixture. At 2% xenon, the calculated VUV emission is about 85% from the resonant atomic xenon state at 147 nm, about 13% from the dimer and about 2% from the resonant 129 nm line. Emission from the 129 nm line is insignificant due to collisional quenching of the xenon 6s' states. The discharge efficiency, defined as the VUV photons/watt dissipated, increases with xenon content with an optimum at about 30% xenon. For opposed electrode geometry, as the xenon concentration is increased from 2% to X% xenon, the simulations show that the applied voltages scale approximately as (X/2)(1/4). At a fixed Pd, a higher pressure yields more VUV emission than using a larger gap width. C1 SANDIA NATL LABS,DEPT PLASMAS & AEROSOLS,ALBUQUERQUE,NM 87185. RP Veerasingam, R (reprint author), PENN STATE UNIV,UNIVERSITY PK,PA 16802, USA. NR 32 TC 25 Z9 25 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD MAY PY 1997 VL 6 IS 2 BP 157 EP 169 DI 10.1088/0963-0252/6/2/009 PG 13 WC Physics, Fluids & Plasmas SC Physics GA XD641 UT WOS:A1997XD64100008 ER PT J AU Bonivert, WD Cushnie, G AF Bonivert, WD Cushnie, G TI NMFRC users survey results SO PLATING AND SURFACE FINISHING LA English DT Editorial Material C1 CAI ENGN,OAKTON,VA 22124. RP Bonivert, WD (reprint author), SANDIA NATL LABS,M-S 9404,BOX 969,LIVERMORE,CA 94551, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ELECTROPLATERS SOC INC PI ORLANDO PA 12644 RESEARCH PKWY, ORLANDO, FL 32826-3298 SN 0360-3164 J9 PLAT SURF FINISH JI Plat. Surf. Finish. PD MAY PY 1997 VL 84 IS 5 BP 96 EP 98 PG 3 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA WX513 UT WOS:A1997WX51300008 ER PT J AU Wu, WL Wallace, WE vanZanten, JH Bauer, BJ Liu, DW Wong, A AF Wu, WL Wallace, WE vanZanten, JH Bauer, BJ Liu, DW Wong, A TI Diffusion of linear polystyrene into crosslinked polystyrene SO POLYMER LA English DT Article DE diffusion; crosslinked network; concentration profile ID CHAINS; NETWORKS; INTERDIFFUSION; INTERFACE AB The diffusion of linear polystyrene (PS) into its crosslinked counterpart was studied using both neutron reflectivity (NR) and forward recoil scattering (FRES). The penetrant molecular weights were monodisperse and ranged from 10000 to 690000 gmol(-1). The molecular weight between crosslinks was kept at 22000 g mol(-1). The crosslinks were introduced by polymerizing styrene monomer in the presence of divinylbenzene. The FRES results revealed the presence of a high molecular weight cut-off for the linear PS above which diffusion could not proceed. The NR results indicated that even at these high molecular weights a certain amount of diffusion did occur but was confined to the first few hundred Angstroms of the interface. A step function in the polymer concentration profile was found at these high molecular weights as expected for systems showing a limited solubility for the diffusant. The counter diffusion of residual sol from the crosslinked network is used to explain certain features of the diffusion profile. (C) 1997 Elsevier Science Ltd. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Wu, WL (reprint author), NIST,DIV POLYMERS,BLDG 224 ROOM B320,GAITHERSBURG,MD 20899, USA. NR 18 TC 17 Z9 17 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0032-3861 J9 POLYMER JI Polymer PD MAY PY 1997 VL 38 IS 11 BP 2583 EP 2594 DI 10.1016/S0032-3861(97)85589-9 PG 12 WC Polymer Science SC Polymer Science GA WZ446 UT WOS:A1997WZ44600001 ER PT J AU Rathke, JW Klingler, RJ Gerald, RE Kramarz, KW Woelk, K AF Rathke, JW Klingler, RJ Gerald, RE Kramarz, KW Woelk, K TI Toroids in NMR spectroscopy SO PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY LA English DT Review DE B-1 field gradients; diffusion coefficient; high pressure; hydroformylation; lithium batteries; metal hydride; electrochemistry; supercritical fluids; toroids; catalysis ID SUPERCRITICAL CARBON-DIOXIDE; HYDROGEN-ATOM TRANSFER; DICOBALT OCTACARBONYL; DIMANGANESE DECACARBONYL; POPULATION-INVERSION; COMPOSITE PULSES; METAL HYDRIDES; BOND STRENGTH; SURFACE COILS; THERMODYNAMICS C1 UNIV BONN,INST PHYS CHEM,D-53115 BONN,GERMANY. RP Rathke, JW (reprint author), ARGONNE NATL LAB,DIV CHEM TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 71 TC 45 Z9 45 U1 2 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0079-6565 J9 PROG NUCL MAG RES SP JI Prog. Nucl. Magn. Reson. Spectrosc. PD MAY PY 1997 VL 30 BP 209 EP 253 DI 10.1016/S0079-6565(96)01037-0 PN 3-4 PG 45 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Chemistry; Physics; Spectroscopy GA XG324 UT WOS:A1997XG32400004 ER PT J AU Ding, YS Fowler, JS Volkow, ND Dewey, SL Wang, GJ Logan, J Gatley, SJ Pappas, N AF Ding, YS Fowler, JS Volkow, ND Dewey, SL Wang, GJ Logan, J Gatley, SJ Pappas, N TI Chiral drugs: Comparison of the pharmacokinetics of [C-11]d-threo and I-threo-methylphenidate in the human and baboon brain SO PSYCHOPHARMACOLOGY LA English DT Article DE methylphenidate; ritalin; dopamine transporter; positron emission tomography; chiral drugs; stereoselectivity ID DOPAMINE TRANSPORTERS; RITALINIC ACID; RAT STRIATUM; BINDING; PET; MICRODIALYSIS; ENANTIOMERS; SITES AB Methylphenidate (Ritalin) is the most commonly prescribed psychoactive medication for children in the US where it is used for the treatment of attention deficit hyperactivity disorder. Methylphenidate is marketed as a racemic mixture of the d-threo and l-threo enantiomers. It is believed that the d enantiomer is responsible for the therapeutic effect of methylphenidate. In this study we labeled the individual enantiomers with carbon-11 and compared their binding and pharmacokinetics in the human and baboon brain. Microdialysis studies in the rat were performed to compare their potency cy in elevating striatal dopamine concentration. Positron emission tomographic (PET) studies with [C-11]d-threo-methylphenidate ([C-11]d-threo-MP) demonstrated highest regional uptake in basal ganglia. In contrast, [C-11]l-threo-methylphenidate ([C-11]l-threo-MP) displayed similar uptakes in all brain regions. The ratios of distribution volumes at the steady-state for the basal ganglia to cerebellum (DVBG/DVCB) ranged from 2.2 to 3.3 for [C-11]d-threo-MP in baboon and human, and only 1.1 for [C-11]l-threo-MP. Pretreatment with unlabeled methylphenidate (0.5 mg/kg) or GBR12909 (3.5 mg/kg) markedly reduced the striatal but not the cerebellar uptake of [C-11]d-threo-MP, whereas there was no effect on DVBG/DVCB for [C-11]l-threo-MP. In the rat, d-threo-MP increased extracellular dopamine concentration by 650% whereas l-threo-MP did not affect dopamine levels. These results indicate that pharmacological specificity of MP resides entirely in the d-threo isomer and directly show that binding of the l-isomer in human brain is mostly nonspecific. C1 BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. SUNY STONY BROOK,DEPT PSYCHIAT,STONY BROOK,NY 11794. RP Ding, YS (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. FU NIDA NIH HHS [DA-06278]; NINDS NIH HHS [NS-15380, NS-15638] NR 35 TC 98 Z9 101 U1 1 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0033-3158 J9 PSYCHOPHARMACOLOGY JI Psychopharmacology PD MAY PY 1997 VL 131 IS 1 BP 71 EP 78 DI 10.1007/s002130050267 PG 8 WC Neurosciences; Pharmacology & Pharmacy; Psychiatry SC Neurosciences & Neurology; Pharmacology & Pharmacy; Psychiatry GA XB426 UT WOS:A1997XB42600010 PM 9181638 ER PT J AU Mesmer, RE Palmer, DA Simonson, JM Holmes, HF Ho, PC Wesolowski, DJ Gruszkiewicz, MS AF Mesmer, RE Palmer, DA Simonson, JM Holmes, HF Ho, PC Wesolowski, DJ Gruszkiewicz, MS TI Experimental studies in high temperature aqueous chemistry at Oak Ridge National Laboratory SO PURE AND APPLIED CHEMISTRY LA English DT Article; Proceedings Paper CT 7th International Symposium on Solubility Phenomena CY JUL 22-25, 1996 CL UNIV LEOBEN, LEOBEN, AUSTRIA HO UNIV LEOBEN ID SODIUM-CHLORIDE; WATER; DENSITIES; DILUTION; MPA AB Experimental research is conducted and models are developed in a longstanding program at Oak Ridge on the aqueous chemistry at high temperatures of broad classes of electrolytes emphasizing thermodynamics of reaction equilibria and excess thermodynamic properties of electrolytes. Our experimental methods, their capabilities, data analysis, and results will be summarized. The relevance of the work to problems in power plants, natural and industrial processes as well as basic solution chemistry and geochemistry are given. Progress in potentiometry, electrical conductivity, flow calorimetry, and isopiestic research will be described. The future in this field demands greater precision in measurements and significant gains in our understanding of the solvation phenomena especially in the vicinity and beyond the critical point for water. The communities who do research on scattering, spectroscopy, and computer simulations can help guide these efforts through studies at extreme conditions. RP Mesmer, RE (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Gruszkiewicz, Miroslaw/L-2389-2016 OI Gruszkiewicz, Miroslaw/0000-0002-6551-6724 NR 34 TC 14 Z9 14 U1 1 U2 5 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0NE SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD MAY PY 1997 VL 69 IS 5 BP 905 EP 914 DI 10.1351/pac199769050905 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA XL583 UT WOS:A1997XL58300002 ER PT J AU Benson, LV Smoot, JP Kashgarian, M SarnaWojcicki, A Burdett, JW AF Benson, LV Smoot, JP Kashgarian, M SarnaWojcicki, A Burdett, JW TI Radiocarbon ages and environments of deposition of the Wono and Trego Hot Springs tephra layers in the Pyramid Lake Subbasin, Nevada SO QUATERNARY RESEARCH LA English DT Article ID MASS-SPECTROMETRY; GREAT-BASIN; CORALS; CARBONATES; LAHONTAN; OXYGEN; SYSTEM AB Uncalibrated radiocarbon data from core PLC92B taken from Wizards Cove in the Pyramid Lake subbasin indicate that the Trego Hot Springs and Wono tephra layers were deposited 23,200+/-300 and 27,300+/-300 C-14 yr B.P. (uncorrected for reservoir effect). Sedimentological data from sites in the Pyramid Lake and Smoke Creek-Black Rock Desert subbasins indicate that the Trego Hot Springs tephra layer was deposited during a relatively dry period when Pyramid Lake was at or below its spill point (1177 m) to the Winnemucca Lake subbasin. The Wono tephra layer was deposited when lake depth was controlled by spill across Emerson Pass sill (1207 m) to the Smoke Creek-Black Rock Desert subbasin. O-18 data from core PLC92B also support the concept that the Trego Hot Springs tephra fell into a relatively shallow Pyramid Lake and that the Wono tephra fell into a deeper spilling lake. (C) 1997 University of Washington. C1 US GEOL SURVEY,RESTON,VA 22092. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. US GEOL SURVEY,MENLO PK,CA 94025. US GEOL SURVEY,DENVER FED CTR,LAKEWOOD,CO 80225. RP Benson, LV (reprint author), US GEOL SURVEY,3215 MARINE ST,BOULDER,CO 80303, USA. RI Kashgarian, Michaele/E-1665-2011 OI Kashgarian, Michaele/0000-0001-7824-8418 NR 17 TC 37 Z9 37 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0033-5894 J9 QUATERNARY RES JI Quat. Res. PD MAY PY 1997 VL 47 IS 3 BP 251 EP 260 DI 10.1006/qres.1997.1897 PG 10 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA WZ990 UT WOS:A1997WZ99000001 ER PT J AU Wise, J Gillen, KT Clough, RL AF Wise, J Gillen, KT Clough, RL TI Time development of diffusion-limited oxidation profiles in a radiation environment SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID THERMALLY AGED ELASTOMERS; OXYGEN DIFFUSION; POLYMERS AB We have previously presented a quantitative model that combines diffusion and kinetic expressions with chemical/mechanical property relationships to predict the time development of diffusion-limited oxidation profiles in polymers. This model was shown to be applicable to thermal aging environments and should be generally applicable to environmental stresses for which total damage to the material is directly proportion to total exposure time. In this work, we use a fluorocarbon elastomer to demonstrate applicability-of the model to ionizing-radiation environments. (C) 1997 Elsevier Science Ltd. RP Wise, J (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 13 TC 38 Z9 38 U1 2 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD MAY PY 1997 VL 49 IS 5 BP 565 EP 573 DI 10.1016/S0969-806X(96)00185-5 PG 9 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA XC776 UT WOS:A1997XC77600012 ER PT J AU Horwitz, EP Chiarizia, R Dietz, ML AF Horwitz, EP Chiarizia, R Dietz, ML TI DIPEX: A new extraction chromatographic material for the separation and preconcentration of actinides from aqueous solution SO REACTIVE & FUNCTIONAL POLYMERS LA English DT Article DE actinides; extraction chromatography; preconcentration; diphosphonic acid ID ION-EXCHANGE RESIN; METAL-IONS; ACID DEPENDENCIES; AM(III); EU(III) AB A novel extraction chromatographic resin consisting of a liquid diphosphonic acid supported on an inert polymeric substrate for the sorption of actinides from strongly acidic chloride media is described. The resin is shown to exhibit stronger affinity for actinides in the tri-, tetra- and hexavalent oxidation states and superior selectivity for americium(III) over aluminum(III) or iron(III) than an analogous chelating ion-exchange resin containing chemically bonded geminally substituted diphosphonic acid functionalities. These properties, along with the comparative ease of recovery of sorbed actinides, make the resin readily applicable to the separation and preconcentration of actinides, as a group, from complex matrices such as soils and bioassay samples. RP Horwitz, EP (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 25 TC 87 Z9 88 U1 3 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-5148 J9 REACT FUNCT POLYM JI React. Funct. Polym. PD MAY PY 1997 VL 33 IS 1 BP 25 EP 36 DI 10.1016/S1381-5148(97)00013-8 PG 12 WC Chemistry, Applied; Engineering, Chemical; Polymer Science SC Chemistry; Engineering; Polymer Science GA XF893 UT WOS:A1997XF89300004 ER PT J AU Heimann, PA Koike, M Hsu, CW Blank, D Yang, XM Suits, AG Lee, YT Evans, M Ng, CY Flaim, C Padmore, HA AF Heimann, PA Koike, M Hsu, CW Blank, D Yang, XM Suits, AG Lee, YT Evans, M Ng, CY Flaim, C Padmore, HA TI Performance of the vacuum ultraviolet high-resolution and high-flux beamline for chemical dynamics studies at the Advanced Light Source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SPECTROMETER AB At the Advanced Light Source an undulator beamline, with an energy range from 6 to 30 eV, has been constructed for chemical dynamics experiments. The higher harmonics of the undulator are suppressed by a novel, windowless gas filter. In one branchline high-flux, 2% bandwidth radiation is directed toward an end station for photodissociation and crossed molecular-beam experiments. A photon flux of 10(16) photon/s has been measured at this end station. In a second branchline a 6.65 m off-plane Eagle monochromator delivers narrow bandwidth radiation to an end station for photoionoization studies. At this second end station a peak flux of 3 x 10(11) was observed for 25 000 resolving power. This monochromator has achieved a resolving power of 70 000 using a 4800 grooves/mm grating, one of the highest resolving powers obtained by a vacuum ultraviolet monochromator. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR XRAY OPT,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. ACAD SINICA,INST ATOM & MOL SCI,TAIPEI 10764,TAIWAN. RP Heimann, PA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ACCELERATOR & FUS RES,BERKELEY,CA 94720, USA. RI Lee, Yuan-Tseh/F-7914-2012; Yang, Xueming/C-8764-2013 NR 20 TC 164 Z9 167 U1 3 U2 23 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1997 VL 68 IS 5 BP 1945 EP 1951 DI 10.1063/1.1148082 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA WZ517 UT WOS:A1997WZ51700004 ER PT J AU Ratliff, LP Bell, EW Parks, DC Pikin, AI Gillaspy, JD AF Ratliff, LP Bell, EW Parks, DC Pikin, AI Gillaspy, JD TI Continuous highly charged ion beams from the National Institute of Standards and Technology electron-beam ion trap SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB We describe our newly modified beam line and present its performance in conjunction with the National Institute of Standards and Technology electron-beam ion trap. We find that, contrary to previously reported results from similar ion sources, the highest intensity time-averaged ion fluxes are achieved by letting the ions boil out of the trap in a continuous stream rather than periodically trap to produce a pulsed beam. We produced continuous beams of 3.0(6) x 10(6) Xe44+ ions per second and lower flux beams of charge states up to Xe49+. Also, in pulsed mode, we created beams with very high peak flux, over 10(10)Xe(44+) ions per second. C1 DIAMOND SEMICOND GRP,GLOUCESTER,MA 01930. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Ratliff, LP (reprint author), NIST,ATOM PHYS DIV,GAITHERSBURG,MD 20899, USA. NR 18 TC 28 Z9 29 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1997 VL 68 IS 5 BP 1998 EP 2002 DI 10.1063/1.1148087 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA WZ517 UT WOS:A1997WZ51700012 ER PT J AU Gouge, MJ Fisher, PW AF Gouge, MJ Fisher, PW TI A cryogenic xenon droplet generator for use in a compact laser plasma x-ray source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A research instrument has been designed, fabricated, and tested that produces similar to 25-100 mu m diameter, liquid xenon droplets on demand at variable repetition rates of 1-100 Hz. Drops have been produced with low spatial dispersion which allows consistent interception by a high power laser beam to produce x-rays for advanced Lithography systems. Experimental sequences of up to 42, min in length have been conducted at 30 Hz, producing over 75 000 xenon drops. This technology allows significant debris reduction from the laser-target interaction. The mass-limited, cryogenic droplets are vaporized, producing no fragments, and the resulting gas can be collected preferentially on a cold surface for later recycling. (C) 1997 American Institute of Physics. RP Gouge, MJ (reprint author), OAK RIDGE NATL LAB,POB 2009,OAK RIDGE,TN 37831, USA. NR 12 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1997 VL 68 IS 5 BP 2158 EP 2162 DI 10.1063/1.1148066 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA WZ517 UT WOS:A1997WZ51700040 ER PT J AU Kozyra, JU Nagy, AF Slater, DW AF Kozyra, JU Nagy, AF Slater, DW TI High-altitude energy source(s) for stable auroral red arcs SO REVIEWS OF GEOPHYSICS LA English DT Review ID ION-CYCLOTRON WAVES; ELECTRON-TEMPERATURE ENHANCEMENT; RING CURRENT IONS; SAR-ARC; PARTICLE INTERACTIONS; EQUATORIAL MAGNETOSPHERE; THERMAL ELECTRONS; SOLAR-ACTIVITY; F-REGION; PLASMA AB Stable auroral red (SAR) arcs have been viewed across the midlatitude night sky with interest since their discovery in 1956. This relatively late discovery (compared to the poleward aurora) is a direct consequence of the subvisual levels of the delicate and diffuse light that makes up the SAR are. Except in rare instances when the emissions actually crossover the threshold to visible levels, optical instruments are required to register their presence and document their morphology and occurrence frequency. SAR arcs are seen as relatively featureless, slowly changing bands of red light that can extend across the entire night sky. Early observations from the ground and from satellites established the relationship between SAR arcs and magnetic disturbances in near-Earth space involving the ring current (a population of high-energy ions trapped in the Earth's magnetic field). The long-lived, soft, red glow of SAR arcs reflects the slow energy loss from the ring current ions as they bounce back and forth in the Earth's confining field geometry, but the exact sequence of physical processes that feed a portion of the ring current energy to the SAR are region is a matter of continuing debate. The midlatitude location of the SAR are bands mirrors the high-altitude location of the outer portion of the ring current torus, but exactly how this positioning is related to gradients or enhancements in the high-altitude extension of the cold ionospheric plasma remained an open question. Our knowledge of SAR arcs and associated signatures now spans more than two full solar cycles. Detailed observations of the high-altitude space environment overlying the SAR are region have been made, indicating that heavy ions from the lower atmosphere, energized by the solar wind interaction with the magnetosphere, play an important role in the SAR are process. Sophisticated models of the coupled high- and low-altitude regions, involved in SAR are formation, paint an interesting picture of the flow of energy between the atmosphere and near-Earth space. This energy flow culminates in the SAR are's glowing red bands, which act, in turn, as sensitive markers of the interaction regions and processes. This emerging view of the SAR are process and the new observational information that provided the underpinnings of its development from a rich framework of past theoretical and observational work is the subject of the present review. C1 PACIFIC NW LAB, DEPT GEOSCI, RICHLAND, WA 99352 USA. RP Kozyra, JU (reprint author), UNIV MICHIGAN, DEPT ATMOSPHER OCEAN & SPACE SCI, SPACE PHYS RES LAB, SPACE RES BLDG, ANN ARBOR, MI 48109 USA. NR 97 TC 71 Z9 71 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD MAY PY 1997 VL 35 IS 2 BP 155 EP 190 DI 10.1029/96RG03194 PG 36 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WX475 UT WOS:A1997WX47500003 ER PT J AU Crandall, DH AF Crandall, DH TI Igniting controversy SO SCIENTIFIC AMERICAN LA English DT Letter C1 US DOE,NATL IGNIT FACIL PROJECT,WASHINGTON,DC 20585. RP Crandall, DH (reprint author), US DOE,OFF INERTIAL FUS,WASHINGTON,DC 20585, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD MAY PY 1997 VL 276 IS 5 BP 10 EP 10 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WU977 UT WOS:A1997WU97700002 ER PT J AU Nieh, TG Kaibyshev, R Hsiung, LM Nguyen, N Wadsworth, J AF Nieh, TG Kaibyshev, R Hsiung, LM Nguyen, N Wadsworth, J TI Subgrain formation and evolution during the deformation of an Al-Mg-Sc alloy at elevated temperatures SO SCRIPTA MATERIALIA LA English DT Article ID DISLOCATION C1 RUSSIAN ACAD SCI,INST MET SUPERPLAST PROBLEMS,UFA 450001,RUSSIA. RP Nieh, TG (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-369,LIVERMORE,CA 94551, USA. RI LAI, JING/F-6526-2010; Nieh, Tai-Gang/G-5912-2011; Kaibyshev, Rustam/G-8804-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746; NR 8 TC 35 Z9 36 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD MAY 1 PY 1997 VL 36 IS 9 BP 1011 EP 1016 DI 10.1016/S1359-6462(96)00479-4 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA WU485 UT WOS:A1997WU48500008 ER PT J AU Hsiung, LM Schwartz, AJ Nieh, TG AF Hsiung, LM Schwartz, AJ Nieh, TG TI In situ observation of deformation-induced interface migration in a fully-lamellar TiAl alloy SO SCRIPTA MATERIALIA LA English DT Article RP Hsiung, LM (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-370,LIVERMORE,CA 94551, USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 5 TC 13 Z9 13 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD MAY 1 PY 1997 VL 36 IS 9 BP 1017 EP 1022 DI 10.1016/S1359-6462(96)00480-0 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA WU485 UT WOS:A1997WU48500009 ER PT J AU Jones, MT Plassmann, PE AF Jones, MT Plassmann, PE TI Parallel algorithms for adaptive mesh refinement SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE adaptive mesh refinement; distributed memory computers; parallel algorithms; sparse matrices; unstructured mesh computation ID ELEMENT AB Computational methods based on the use of adaptively constructed nonuniform meshes reduce the amount of computation and storage necessary to perform many scientific calculations. The adaptive construction of such nonuniform meshes is an important part of these methods. In this paper, we present a parallel algorithm for adaptive mesh refinement that is suitable for implementation on distributed-memory parallel computers. Experimental results obtained on the Intel DELTA are presented to demonstrate that for scientific computations involving the finite element method, the algorithm exhibits scalable performance and has a small run time in comparison with other aspects of the scientific computations examined. It is also shown that the algorithm has a fast expected running time under the parallel random access machine (PRAM) computation model. C1 ARGONNE NATL LAB,DIV MATH & COMP SCI,ARGONNE,IL 60439. RP Jones, MT (reprint author), UNIV TENNESSEE,DEPT COMP SCI,KNOXVILLE,TN 37966, USA. NR 21 TC 28 Z9 28 U1 0 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY PY 1997 VL 18 IS 3 BP 686 EP 708 DI 10.1137/S106482759528065X PG 23 WC Mathematics, Applied SC Mathematics GA WW816 UT WOS:A1997WW81600003 ER PT J AU Foster, IT Worley, PH AF Foster, IT Worley, PH TI Parallel algorithms for the spectral transform method SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE spectral transform method; parallel algorithms; performance analysis ID MATRIX TRANSPOSITION; PERFORMANCE; SCALABILITY; HYPERCUBES; EQUATIONS; FFTS AB The spectral transform method is a standard numerical technique for solving partial differential equations on a sphere and is widely used in atmospheric circulation models. Re cent research has identified several promising algorithms for implementing this method on massively parallel computers. however, no detailed comparison of the different algorithms has previously been attempted. In this paper, we describe these different parallel algorithms and report on computational experiments that we have conducted to evaluate their efficiency on parallel computers. The experiments used a testbed code that solves the nonlinear shallow water equations on a sphere: considerable care was taken to ensure that the experiments provide a fair comparison of the different algorithms and that the results are relevant to global models. We focus on hypercube- and mesh-connected multicomputers with cut-through routing, such as the Intel iPSC/860, DELTA, and Paragon, and the nCUBE/2, but we also indicate how the results extend to other parallel computer architectures. The results of this study are relevant not only to the spectral transform method but also to multidimensional fast Fourier transforms (FFTs) and other parallel transforms. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Foster, IT (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 39 TC 33 Z9 34 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY PY 1997 VL 18 IS 3 BP 806 EP 837 DI 10.1137/S1064827594266891 PG 32 WC Mathematics, Applied SC Mathematics GA WW816 UT WOS:A1997WW81600008 ER PT J AU Malekani, K Rice, JA Lin, JS AF Malekani, K Rice, JA Lin, JS TI The effect of sequential removal of organic matter on the surface morphology of humin SO SOIL SCIENCE LA English DT Article ID FRACTAL SURFACES; MARINE-SEDIMENTS; SOIL; SUBSTANCES; ACIDS; POLLUTANTS; ADSORPTION; PARTITION; RESIDUES; WATER AB Natural organic matter in soils interacts with surfaces of inorganic materials, primarily aluminosilicates or clay minerals, to form a strongly associated organo-mineral composite known as humin, Because of humin's insolubility, it is recognized as the primary sorbent of many anthropogenic organic compounds (AOCs) introduced into soil systems, This recognition has significant implications for understanding the fate and transport of AOCs, the effective remediation of contaminated sites, and the formulation and application of various agrochemicals. Humin was isolated from four soil samples. Surface area, surface charge, porosity measurements, and fractal analysis of small-angle X-ray scattering data were used to characterize changes in the surface properties resulting from selective removal of the various components of organic matter from humin, Organic matter was removed selectively from humin by Soxhlet extraction, disaggregation with the methylisobutylketone (MIBK) method, and bromine oxidation,The surface fractal dimensions decreased while surface area increased, and surface pore size decreased upon removal of organic matter, These results suggest that the mineral components of humin have smooth surfaces over length scales of similar to 1 to 15 nm, and that it is the organic matter coatings that are responsible for their surface roughness, The surfaces of all the components of humin were found to be dominated by micro- and mesopores that could be responsible for humin's high sorptive uptake of organic chemicals. C1 S DAKOTA STATE UNIV,DEPT CHEM & BIOCHEM,BROOKINGS,SD 57007. OAK RIDGE NATL LAB,DIV SOLID STATE,CTR SMALL ANGLE SCATTERING,OAK RIDGE,TN 37831. NR 54 TC 36 Z9 41 U1 2 U2 12 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 0038-075X J9 SOIL SCI JI Soil Sci. PD MAY PY 1997 VL 162 IS 5 BP 333 EP 342 DI 10.1097/00010694-199705000-00003 PG 10 WC Soil Science SC Agriculture GA XC198 UT WOS:A1997XC19800003 ER PT J AU Onken, BM Adriano, DC AF Onken, BM Adriano, DC TI Arsenic availability in soil with time under saturated and subsaturated conditions SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID SORPTION AB Loss of As from solution in reduced soils has long been attributed to volatilization of As as arsines. This study was conducted to determine whether loss of As from soil solution could be accounted for by increases in surface-bound forms of As. Pickney sand (sandy, siliceous, thermic Cumulic Humaquept) was treated with sodium arsenate and sodium arsenite and incubated under saturated and subsaturated conditions for up to 68 d. Sequential extraction of As by NH4Cl, NH4F, NaOH, and H2SO4 was performed to monitor the redistribution of As between different fractions with time. By determining the As concentration present in sequentially extractable forms, it was demonstrated that As became more recalcitrant in soil with time. Arsenic added in water-soluble form became more tightly bound to the soil as evidenced by the necessity of stronger extractants to remove added As. The conversion (curing) of As to more insoluble forms occurred in saturated soils where the pe/pH status was in the arsenite stability held and in subsaturated soils where the pe/pH status was in the arsenate stability field. The rate at which As was converted to more insoluble (and possibly less bioavailable) forms was as rapid in saturated soils as in unsaturated soils. Arsenic was conserved during the experiment with no apparent loss of As from the system through 68 d. C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,DIV BIOGEOCHEM,AIKEN,SC 29802. RP Onken, BM (reprint author), UNIV DELAWARE,DEPT PLANT & SOIL SCI,149 TOWNSEND HALL,NEWARK,DE 19717, USA. NR 24 TC 62 Z9 72 U1 0 U2 12 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAY-JUN PY 1997 VL 61 IS 3 BP 746 EP 752 PG 7 WC Soil Science SC Agriculture GA XC996 UT WOS:A1997XC99600007 ER PT J AU Dosskey, MG Bertsch, PM AF Dosskey, MG Bertsch, PM TI Transport of dissolved organic matter through a sandy forest soil SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID ALUMINUM CHEMISTRY; HUMIC SUBSTANCES; CENTRAL CASCADES; CARBON DYNAMICS; STREAM; PODZOLIZATION; ECOSYSTEM; ORIGIN; ACIDS; WATER AB We assessed the transport of dissolved organic matter (DOM) through a sandy, Ultisol forest soil on the southeastern U.S. Coastal Plain, and contrasted the results with similar studies from other forest regions, to test the hypothesis that DOM transport is greater through sandy Ultisols than finer textured Ultisols and Spodosols. Within a small headwater catchment, concentrations of dissolved organic carbon (DOG), a measure of DOM, were measured in soil solution at three depths (10, 30, and 90 cm) in sand A and E horizons of soil profiles, and in sand along the valley bottom at 198- to 264-cm depth in shallow groundwater. Water samples were collected after every rainfall event for 21 mo using zero-tension lysimeters, suction samplers, and piezometers. Mean concentration of DOC in soil water decreased from 25.5 mg C L-1 at 10-cm depth to 13.7 mg C L-1 at 30 cm, and to 1.8 mg C L-1 at 76 to 99 cm, before contacting clay-enriched horizons. All valley bottom stations consistently averaged between 0.3 and 2.1 mg C L-1. We did not find significant seasonal patterns, nor a correlation between DOC concentration and magnitude of rainfall events. We estimate that the nux of DOC decreased more sharply with soil depth than concentration due to attenuation of water transport through the soil profile. Compared with literature data from other forest regions, our results do not support the hypothesis that there is greater DOM transport through sandy upland soils on the Coastal Plain. Our results suggest that this is due to strong DOM retention within deep sand E horizons of these soils. Thus, strong DOM retention in forest soils appears to occur across a broader range of soil types than those exhibiting podzolization or having high clay content. C1 UNIV GEORGIA, DIV BIOGEOCHEM, SAVANNAH RIVER ECOL LAB, AIKEN, SC 29802 USA. RP Dosskey, MG (reprint author), UNIV NEBRASKA, DEPT FORESTRY FISHERIES & WILDLIFE, 101 PLANT IND, LINCOLN, NE 68583 USA. NR 54 TC 33 Z9 58 U1 4 U2 21 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 USA SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAY-JUN PY 1997 VL 61 IS 3 BP 920 EP 927 PG 8 WC Soil Science SC Agriculture GA XC996 UT WOS:A1997XC99600030 ER PT J AU Ju, HL Sohn, H AF Ju, HL Sohn, H TI Role of grain boundaries in double exchange manganite oxides La(1-x)A(x)MnO(3) (A=Ba, Ca) SO SOLID STATE COMMUNICATIONS LA English DT Article DE magnetically ordered materials; grain boundary; electronic transport ID GIANT MAGNETORESISTANCE; EPITAXIAL ND0.7SR0.3MNO3-DELTA; SINGLE-CRYSTALS; THIN-FILMS; MAGNETIZATION; LA1-XSRXMNO3; RESISTIVITY; DEPENDENCE AB We report the study of magnetotransport and magnetic properties of manganite oxides La(1-x)A(x)MnO(3) (A = Ba, Ca). We have observed that polycrystalline manganite shows a different resistivity behavior from that of single crystalline material in that the former shows a small rho(P)/rho(5 K) (rho (P): peak resistivity, rho(5 K): resistivity at 5 K) ratio and a large magnetoresistance (MR) effect at T much less than T-c, whereas the latter shows a large rho(P)/rho(5 K) ratio and no significant MR at low temperature, due to grain boundary contribution to the resistivity. A La0.67Ba0.33MnO2.99 sample with a polycrystal size of 5 mu m showed the grain boundary resistivity 150 times as large as the grain resistivity at 5 K. A possible origin of low-field MR in polycrystalline manganites has been discussed. (C) 1997 Elsevier Science Ltd. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Ju, HL (reprint author), UNIV MARYLAND,CTR SUPERCONDUCT RES,DEPT PHYS,COLLEGE PK,MD 20742, USA. NR 14 TC 85 Z9 93 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAY PY 1997 VL 102 IS 6 BP 463 EP 466 DI 10.1016/S0038-1098(97)00031-8 PG 4 WC Physics, Condensed Matter SC Physics GA WU333 UT WOS:A1997WU33300007 ER PT J AU Maiti, A Mahan, GD Pantelides, ST AF Maiti, A Mahan, GD Pantelides, ST TI Dynamical simulations of nonequilibrium processes - Heat flow and the Kapitza resistance across grain boundaries SO SOLID STATE COMMUNICATIONS LA English DT Article DE semiconductors; grain boundaries; heat conduction; phonons ID MOLECULAR-DYNAMICS; COMPUTER-SIMULATION; LATTICES AB We report molecular dynamics simulations of nonequilibrium heat flow in a solid system in the local-equilibrium or hydrodynamic approximation and demonstrate that local equilibrium can be achieved in small numbers of atomic layers over long simulation runs. From the dynamical simulations, we calculate the thermal boundary (Kapitza) resistance that arises from heat flow across Si grain boundaries and compare with the traditional approach based on calculating the transmission and reflection of harmonic phonons at the grain boundary. C1 VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. RP Maiti, A (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 23 TC 160 Z9 163 U1 2 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAY PY 1997 VL 102 IS 7 BP 517 EP 521 DI 10.1016/S0038-1098(97)00049-5 PG 5 WC Physics, Condensed Matter SC Physics GA WV280 UT WOS:A1997WV28000004 ER PT J AU Miyamoto, Y Cohen, ML Louie, SG AF Miyamoto, Y Cohen, ML Louie, SG TI Theoretical investigation of graphitic carbon nitride and possible tubule forms SO SOLID STATE COMMUNICATIONS LA English DT Article ID BORON; NANOTUBES; STABILITY; SOLIDS; STRESS AB Graphitic forms of carbon nitride are investigated by means of first principles pseudopotential total-energy calculations. Stabilities of single layers of graphitic C3N4 and CN are examined by geometrical optimization and by calculating phonon frequencies. Single layers of C3N4 and CN are both found to be stabilized with a C atom displacement away from the sheet. Possible tubule forms of carbon nitride and their electronic properties are discussed. (C) 1997 Elsevier Science Ltd. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Miyamoto, Y (reprint author), NEC CORP LTD,FUNDAMENTAL RES LABS,34 MIYUKIGAOKA,TSUKUBA,IBARAKI 305,JAPAN. OI Miyamoto, Yoshiyuki/0000-0001-6834-0499 NR 16 TC 190 Z9 193 U1 1 U2 44 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAY PY 1997 VL 102 IS 8 BP 605 EP 608 DI 10.1016/S0038-1098(97)00025-2 PG 4 WC Physics, Condensed Matter SC Physics GA WX146 UT WOS:A1997WX14600008 ER PT J AU Hong, J Lee, JW Vartuli, CB Mackenzie, JD Donovan, SM Abernathy, CR Crockett, RV Pearton, SJ Zolper, JC Ren, F AF Hong, J Lee, JW Vartuli, CB Mackenzie, JD Donovan, SM Abernathy, CR Crockett, RV Pearton, SJ Zolper, JC Ren, F TI High temperature annealing of GaN, InN, AlN and related alloys SO SOLID-STATE ELECTRONICS LA English DT Article ID MOLECULAR-BEAM EPITAXY; ION-IMPLANTED GAAS; GROWTH; SLIP AB Transient thermal processing is employed for implant activation, contact alloying, implant isolation and dehydrogenation during III-nitride device fabrication. We have compared use of InN and AlN powder as methods for providing a N-2 partial pressure within a graphite susceptor for high temperature annealing of GaN, InN AlN, InAlN and InGaN. The AlN powder provides adequate surface protection to temperatures of similar to 1100 degrees C for AlN, greater than or equal to 1050 degrees C for GaN, similar to 600 degrees C for InN and similar to 800 degrees C for the ternary alloys. While the InN powder provides a higher N-2 partial pressure than AlN powder, at temperatures above similar to 750 degrees C the evaporation of In is sufficiently high to produce condensation of In droplets on the surfaces of the annealed samples. (C) 1997 Elsevier Science Ltd. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. AT&T BELL LABS,LUCENT TECHNOL,MURRAY HILL,NJ 07974. RP Hong, J (reprint author), UNIV FLORIDA,DEPT MAT SCI & ENGN,GAINESVILLE,FL 32611, USA. NR 27 TC 5 Z9 5 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1101 J9 SOLID STATE ELECTRON JI Solid-State Electron. PD MAY PY 1997 VL 41 IS 5 BP 681 EP 694 DI 10.1016/S0038-1101(96)00219-5 PG 14 WC Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA WZ800 UT WOS:A1997WZ80000005 ER PT J AU Jones, RM MacDonald, ME Branda, J Altherr, MR Louis, DN Schmidt, EV AF Jones, RM MacDonald, ME Branda, J Altherr, MR Louis, DN Schmidt, EV TI Assignment of the human gene encoding eukaryotic initiation factor 4E (EIF4E) to the region q21-25 on chromosome 4. SO SOMATIC CELL AND MOLECULAR GENETICS LA English DT Article ID CAP-BINDING PROTEIN; RNA 5' CAP; TRANSLATIONAL CONTROL; EIF-4E; TRANSFORMATION; FACTOR-EIF-4E; EXPRESSION; RECEPTOR; MYC AB We recently cloned genomic sequences containing the promoter region for the messenger RNA cap binding protein (eIF4E). As the rate-limiting step in translation, eukaryotic initiation factor 4E is important in cellular growth control. Using oligonucleotide primers specific for the promoter region in polymerase chain reactions (PCR), we amplified the human gene in a chromosome 4-specific human/rodent somatic cell panel. This panel mapped single copy genomic sequences for eIF4E in the region 4q21 to 4q25. C1 MASSACHUSETTS GEN HOSP,CHILDRENS SERV,BOSTON,MA 02114. MASSACHUSETTS GEN HOSP,MOL NEUROGENET UNIT,CHARLESTOWN,MA 02129. LOS ALAMOS NATL LAB,GENOM & STRUCT BIOL GRP,LOS ALAMOS,NM 87545. MASSACHUSETTS GEN HOSP,DEPT PATHOL,BOSTON,MA 02114. RP Jones, RM (reprint author), MASSACHUSETTS GEN HOSP,CTR CANC,BLDG 149,13TH ST,CHARLESTOWN,MA 02129, USA. FU NCI NIH HHS [R01-CA63117]; NHGRI NIH HHS [HG 00169]; NINDS NIH HHS [T32NS07340-04] NR 23 TC 0 Z9 0 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0740-7750 J9 SOMAT CELL MOLEC GEN JI Somat.Cell Mol.Genet. PD MAY PY 1997 VL 23 IS 3 BP 221 EP 223 DI 10.1007/BF02721373 PG 3 WC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity GA XZ594 UT WOS:A1997XZ59400005 PM 9330633 ER PT J AU Ueki, K Ramaswamy, S Billings, SJ Mohrenweiser, HW Louis, DN AF Ueki, K Ramaswamy, S Billings, SJ Mohrenweiser, HW Louis, DN TI Chromosomal localization to 19q13.3, partial genomic structure and 5' cDNA sequence of the human symplekin gene SO SOMATIC CELL AND MOLECULAR GENETICS LA English DT Article ID TUMOR-SUPPRESSOR GENE; 19Q; PROTEIN; MAP AB Exon trapping from cosmids mapping to chromosome 19q13.3 yielded 6 exonic sequences that matched the human symplekin gene, which encodes a tight junction-related protein. One exonic sequence identified a 4.0 kb brain cDNA clone, R6E1, which contained 302 bp 5' to the originally reported 3.7 kb symplekin cDNA. A portion of this novel 5' sequence matched an additional trapped exonic sequence which was obtained from the most telomeric cosmid analyzed. The symplekin gene thus lies in a telomeric-to-centromeric direction on 19q13.3. Only three cosmids from a large 19q13.3 contig hybridized with R6E1, thereby assigning the symplekin gene to a 40 kb region immediately telomeric to gene 59 and the DM protein kinase gene. The 5' end of the R6E1 clone has a potential initiation codon with a strong Kozak sequence and Northern blot analysis detected a 4.2 kb signal in most human tissues, indicating that R6E1 may be a complete cDNA sequence. Based on the trapped exonic sequences, twelve exon-intron boundaries were predicted. C1 MASSACHUSETTS GEN HOSP,NEUROSURG SERV,CHARLESTOWN,MA 02129. HARVARD UNIV,SCH MED,CHARLESTOWN,MA 02129. LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA 94550. RP Ueki, K (reprint author), MASSACHUSETTS GEN HOSP,MOL NEUROONCOL LAB,DEPT PATHOL NEUROPATHOL,CHARLESTOWN,MA 02129, USA. FU NCI NIH HHS [CA 69285] NR 8 TC 6 Z9 7 U1 0 U2 0 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0740-7750 J9 SOMAT CELL MOLEC GEN JI Somat.Cell Mol.Genet. PD MAY PY 1997 VL 23 IS 3 BP 229 EP 231 DI 10.1007/BF02721375 PG 3 WC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Cell Biology; Genetics & Heredity GA XZ594 UT WOS:A1997XZ59400007 PM 9330635 ER PT J AU Laqua, K Schrader, B Hoffmann, GG Moore, DS VoDinh, T AF Laqua, K Schrader, B Hoffmann, GG Moore, DS VoDinh, T TI Nomenclature, symbols, units and their usage in spectrochemical analysis .11. Detection of radiation SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Article C1 UNIV ESSEN GESAMTHSCH,INST PHYS & THEORET CHEM,D-45117 ESSEN,GERMANY. LOS ALAMOS NATL LAB,DIV CHEM SCI & TECHNOL,LOS ALAMOS,NM 87545. OAK RIDGE NATL LAB,ADV MONITORING DEV GRP,OAK RIDGE,TN 37831. RI Moore, David/C-8692-2013 NR 0 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD MAY PY 1997 VL 52 IS 5 BP 537 EP 552 DI 10.1016/S0584-8547(97)83359-9 PG 16 WC Spectroscopy SC Spectroscopy GA XG741 UT WOS:A1997XG74100001 ER PT J AU Ager, JW Anders, S Brown, IG Nastasi, M Walter, KC AF Ager, JW Anders, S Brown, IG Nastasi, M Walter, KC TI Multilayer hard carbon films with low wear rates SO SURFACE & COATINGS TECHNOLOGY LA English DT Article DE multilayer hard carbon films; vacuum-arc deposition; multilayer structure; wear rate ID AMORPHOUS-CARBON; DEPOSITION; DIAMOND; VACUUM; STRESS AB Vacuum arc deposition has been used to grow thin, ultrahard carbon films. Multilayer structures consisting of four alternating double layers of carbon with sp(3) contents of 80 and 40%, respectively, were grown using a pulse bias technique for ion energy control. The relative proportion of the soft layer (40% sp(3) content) in the multilayer structure was varied from 10 to 90%. The hardness of the multilayer structure is a weighted average of the hardnesses of the component layers. The overall compressive growth stress is less than would be expected from the proportions of the layer components. Pin-on-disk wear testing showed that multilayer films have a lower wear rate than monolithic films especially at higher loads. The lowest wear rate was measured in a film with alternating layers of approximately equal thicknesses of the hard and soft layers. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV ACCELERATOR & FUS RES, BERKELEY, CA 94720 USA. LOS ALAMOS NATL LAB, CTR MAT SCI, LOS ALAMOS, NM 87545 USA. RP Ager, JW (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, CTR ADV MAT, DIV MAT SCI, BERKELEY, CA 94720 USA. RI Raoux, Simone/G-3920-2016; OI Ager, Joel/0000-0001-9334-9751 NR 18 TC 18 Z9 19 U1 0 U2 14 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD MAY 1 PY 1997 VL 91 IS 1-2 BP 91 EP 94 DI 10.1016/S0257-8972(97)80004-7 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA XF003 UT WOS:A1997XF00300015 ER PT J AU Knyazev, BA Greenly, JB Hammer, DA Krastelev, EG Cuneo, ME AF Knyazev, BA Greenly, JB Hammer, DA Krastelev, EG Cuneo, ME TI Dynamics of the anode plasma in the magnetically insulated diode of the COBRA ion accelerator by modified laser deflectometry SO TECHNICAL PHYSICS LETTERS LA English DT Article AB A new type of optical system for measurements of laser beam deflection has been developed and implemented experimentally. The refractive index gradient in the anode plasma of a megavolt magnetically insulated diode in a high-power ion accelerator has been measured with submicron resolution. The refractive index distribution in the layer was measured during the pulse and the average electron density in the layer was determined. (C) 1997 American Institute of Physics. C1 NOVOSIBIRSK STATE UNIV,NOVOSIBIRSK 630090,RUSSIA. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Knyazev, BA (reprint author), CORNELL UNIV,PLASMA STUDIES LAB,ITHACA,NY 14853, USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1063-7850 J9 TECH PHYS LETT+ JI Tech. Phys. Lett. PD MAY PY 1997 VL 23 IS 5 BP 401 EP 402 DI 10.1134/1.1261695 PG 2 WC Physics, Applied SC Physics GA XN224 UT WOS:A1997XN22400029 ER PT J AU Rocke, DM Jones, G AF Rocke, DM Jones, G TI Optimal design for ELISA and other forms of immunoassay SO TECHNOMETRICS LA English DT Article DE calibration; log-logistic curve; precision ID LINKED-IMMUNOSORBENT-ASSAY; ENZYME; URINE; CALIBRATION; MODEL AB In enzyme-linked immunosorbent assay (ELISA), as well as in many other kinds of immunoassay, a log-logistic or similar-shaped calibration curve is fit using standards at a series of known levels and then used to transform the measured values for the unknowns into estimated concentrations. The choice of the number of standards, the concentration of the standards, and the number of replicates of the standards and of the unknowns all affect the precision of the measurement. This article develops an optimal design paradigm for this type of problem and shows how optimal choices can be calculated so that the system achieves the maximum precision of which it is capable. Although exact calculation of optimal designs requires use of a computer program, close approximations to the optimum can be derived from simple rules for hand calculation. RP Rocke, DM (reprint author), LAWRENCE LIVERMORE NATL LAB,GRAD SCH MANAGEMENT,DAVIS,CA 95616, USA. RI Rocke, David/I-7044-2013; OI Rocke, David/0000-0002-3958-7318; Jones, Geoffrey/0000-0002-6244-1245 NR 28 TC 6 Z9 6 U1 0 U2 0 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD MAY PY 1997 VL 39 IS 2 BP 162 EP 170 PG 9 WC Statistics & Probability SC Mathematics GA WV217 UT WOS:A1997WV21700005 ER PT J AU CohenSolal, E LeTreut, H AF CohenSolal, E LeTreut, H TI Role of the oceanic heat transport in climate dynamics - A sensitivity study with an atmospheric general circulation model SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID ENERGY TRANSPORTS; MIXED-LAYER; SEA ICE; BUDGETS; SURFACE; FLUXES; ALBEDO; MASS; GCM; PARAMETERIZATIONS AB Estimating meridional ocean heat transport from the present generation of atmospheric general circulation models, assuming energetic equilibrium, leads to a large variety of results, depending on the model. The current uncertainty on such an important process may cause significant errors in coupled atmosphere/ocean models. To determine the possible nature of these errors, investigate how the prescription of the oceanic heat transport can affect the results of a coupled surface ocean/atmosphere model where the ocean is limited to thermodynamics and turbulent fluxes but sea-ice is included. In particular, we study the response of the surface fluxes and atmospheric transport to a reduction of the ocean transport. We focus on the initial phase, where these feedback effects begin to develop while the model is still realistic. The model response is strongly dependent on a combination of features: changes in the Hadley cell circulation, the atmospheric heat transport, the radiative and turbulent fluxes at the surface, changes of the radiative fluxes at the top of the atmosphere. In this study, we examine the partitioning between these different effects. It is shown that the atmosphere partly takes up the missing ocean transport, but that this leads to a change in the cloud/radiative equilibrium of the ITCZ region. C1 ECOLE NORMALE SUPER, METEOROL DYNAM LAB, CNRS, F-75231 PARIS 05, FRANCE. RP LAWRENCE LIVERMORE NATL LAB, PROGRAM CLIMATE MODEL DIAG & INTERCOMPARISON, POB 808, L-264, LIVERMORE, CA 94550 USA. NR 52 TC 9 Z9 9 U1 0 U2 0 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6495 EI 1600-0870 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD MAY PY 1997 VL 49 IS 3 BP 371 EP 387 DI 10.1034/j.1600-0870.1997.t01-2-00005.x PG 17 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA XF082 UT WOS:A1997XF08200005 ER PT J AU Jones, DA Poje, AC Margolin, LG AF Jones, DA Poje, AC Margolin, LG TI Resolution effects and enslaved finite-difference schemes for a double gyre, shallow-water model SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article; Proceedings Paper CT Meeting on Advances in Geophysical Fluid Dynamics and Turbulence CY MAY 16-19, 1996 CL ARIZONA STATE UNIV, TEMPE, AZ HO ARIZONA STATE UNIV ID WORLD OCEAN CIRCULATION; WIND-DRIVEN; EDDY RESOLUTION; REDUCED-GRAVITY; DIFFUSION; GCM AB We study numerical solutions of the reduced-gravity shallow-water equation on a beta plane, subjected to a sinusoidally varying wind forcing leading to the formation of a double gyre circulation. As expected the dynamics of the numerical solutions are highly dependent on the grid resolution and the given numerical algorithm. In particular, the statistics of the solutions are critically dependent on the scheme's ability to resolve the Rossby deformation radius. We present a method, applicable to any finite-difference scheme, which effectively increases the spatial resolution of the given algorithm without changing its temporal stability or memory requirements. This enslaving method makes use of properties of the governing equations in the absence of time derivatives to reduce the overall truncation error. By examining statistical measures of stochastic solutions at resolutions near the Rossby radius, we show that the enslaved schemes are capable of reproducing statistics of standard schemes computed at twice the resolution. C1 Arizona State Univ, Dept Math, Tempe, AZ 85287 USA. Brown Univ, Div Appl Math, Providence, RI 02912 USA. Los Alamos Natl Lab, IGPP, Los Alamos, NM 87545 USA. RP Arizona State Univ, Dept Math, Tempe, AZ 85287 USA. NR 26 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0935-4964 EI 1432-2250 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD MAY-JUN PY 1997 VL 9 IS 3-4 BP 269 EP 280 DI 10.1007/s001620050044 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YR835 UT WOS:000071535300008 ER PT J AU Nadiga, BT Hecht, MW Margolin, LG Smolarkiewicz, PK AF Nadiga, BT Hecht, MW Margolin, LG Smolarkiewicz, PK TI On simulating flows with multiple time scales using a method of averages SO THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS LA English DT Article; Proceedings Paper CT Meeting on Advances in Geophysical Fluid Dynamics and Turbulence CY MAY 16-19, 1996 CL ARIZONA STATE UNIV, TEMPE, ARIZONA HO ARIZONA STATE UNIV ID NUMERICAL-METHODS; OCEAN; EQUATIONS; STABILITY; MODEL AB We present a new method, based on averaging, to simulate certain systems with multiple time scales efficiently and demonstrate its utility in the context of the shallow-water equations. We first develop the method in a simple linear setting and analytically prove its stability. This is followed by an extension to the full equations and a presentation of a computational model for it. In this preliminary study, we find that the new method produces results that are very close to a fully explicit (spatially and temporally) second-order accurate scheme and much better than a fully explicit (spatially and temporally) first-order accurate scheme, while costing less than the first-order accurate scheme. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Nadiga, BT (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0935-4964 J9 THEOR COMP FLUID DYN JI Theor. Comput. Fluid Dyn. PD MAY-JUN PY 1997 VL 9 IS 3-4 BP 281 EP 292 DI 10.1007/s001620050045 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA YR835 UT WOS:000071535300009 ER PT J AU Savina, MR Lykke, KR AF Savina, MR Lykke, KR TI Chemical imaging of surfaces with laser desorption mass spectrometry SO TRAC-TRENDS IN ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION AB Mass spectrometric imaging of surfaces can reveal features not evident in micrographs. The use of two lasers, one to desorb atoms and molecules and a second to ionize them in the gas phase, produces a reasonably steady ion yield as the desorption spot is rastered across a surface. When combined with a time-of-flight mass analyzer, the result is a simple instrument capable of molecular imaging with micron resolution. C1 NIST,DIV OPT TECHNOL,GAITHERSBURG,MD 20899. RP Savina, MR (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 31 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-9936 J9 TRAC-TREND ANAL CHEM JI Trac-Trends Anal. Chem. PD MAY PY 1997 VL 16 IS 5 BP 242 EP 252 DI 10.1016/S0165-9936(97)00028-9 PG 11 WC Chemistry, Analytical SC Chemistry GA XJ329 UT WOS:A1997XJ32900016 ER PT J AU Jager, HI Pert, EJ AF Jager, HI Pert, EJ TI Testing the independence of microhabitat preferences and flow .2. Comment SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Editorial Material ID ECOLOGY C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT FISHERIES & WILDLIFE SCI,BLACKSBURG,VA 24061. RP Jager, HI (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. NR 7 TC 4 Z9 4 U1 0 U2 1 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 1997 VL 126 IS 3 BP 537 EP 540 DI 10.1577/1548-8659-126.3.537 PG 4 WC Fisheries SC Fisheries GA XN047 UT WOS:A1997XN04700019 ER PT J AU LoCurto, GJ Zhang, X Zakirov, V Bucklin, RA VuQuoc, L Hanes, DM Walton, OR AF LoCurto, GJ Zhang, X Zakirov, V Bucklin, RA VuQuoc, L Hanes, DM Walton, OR TI Soybean impacts: Experiments and dynamic simulations SO TRANSACTIONS OF THE ASAE LA English DT Article DE soybeans; coefficient of restitution AB The coefficient of restitution of soybeans impacting aluminum, glass, and acrylic was measured for drop heights of 15.1 cm, 29.2 cm, and 51.1 cm and at moisture contents of 10.7% and 15.5% (db). Statistically significant changes in the coefficient of restitution were produced by changes in material surface, drop height and moisture content. Changes in moisture content from 10.7% to 15.5% (db) reduced the average coefficient of restitution from 0.69 to 0.59, a decrease of approximately 14%. Over the range of impact velocities tested (1.7 to 3.2 m/s produced by drops from heights from 15.1 cm to 51.1 cm) the coefficient of restitution was relatively insensitive to velocity, decreasing by less than 5% from 0.65 to 0.62. The measured values of coefficient of restitution were used as inputs to algorithms describing the behavior of a single bouncing soybean. The algorithm predicted reasonable results when compared to the observed behavior of dropped soybeans. C1 UNIV FLORIDA,DEPT AGR & BIOL ENGN,GAINESVILLE,FL 32611. UNIV FLORIDA,DEPT AEROSP ENGN MECH & ENGN SCI,GAINESVILLE,FL 32611. UNIV FLORIDA,DEPT COASTAL & OCEANOG ENGN,GAINESVILLE,FL 32611. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA. NR 13 TC 19 Z9 22 U1 0 U2 3 PU AMER SOC AGRICULTURAL ENGINEERS PI ST JOSEPH PA 2950 NILES RD, ST JOSEPH, MI 49085-9659 SN 0001-2351 J9 T ASAE JI Trans. ASAE PD MAY-JUN PY 1997 VL 40 IS 3 BP 789 EP 794 PG 6 WC Agricultural Engineering SC Agriculture GA XM447 UT WOS:A1997XM44700035 ER PT J AU Cranmer, SL Magowan, C Liang, J Coppel, RL Cooke, BM AF Cranmer, SL Magowan, C Liang, J Coppel, RL Cooke, BM TI An alternative to serum for cultivation of Plasmodium falciparum in vitro SO TRANSACTIONS OF THE ROYAL SOCIETY OF TROPICAL MEDICINE AND HYGIENE LA English DT Article DE malaria; Plasmodium falciparum; cultivation in vitro; serum substitute ID CYTOADHERENCE; PARASITES; ANTIGEN C1 MONASH UNIV,DEPT MICROBIOL,CLAYTON,VIC 3168,AUSTRALIA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. RI Coppel, Ross/A-6626-2008 OI Coppel, Ross/0000-0002-4476-9124 FU NIDDK NIH HHS [DK32094-10] NR 18 TC 129 Z9 129 U1 0 U2 2 PU ROYAL SOC TROPICAL MEDICINE PI LONDON PA MANSON HOUSE 26 PORTLAND PLACE, LONDON, ENGLAND W1N 4EY SN 0035-9203 J9 T ROY SOC TROP MED H JI Trans. Roy. Soc. Trop. Med. Hyg. PD MAY-JUN PY 1997 VL 91 IS 3 BP 363 EP 365 DI 10.1016/S0035-9203(97)90110-3 PG 3 WC Public, Environmental & Occupational Health; Tropical Medicine SC Public, Environmental & Occupational Health; Tropical Medicine GA XE698 UT WOS:A1997XE69800035 PM 9231219 ER PT J AU Gebre, GM Brandle, JR Kuhns, MR AF Gebre, GM Brandle, JR Kuhns, MR TI Influence of rewatering and time of sampling on solute accumulation of two Populus deltoides clones SO TREE PHYSIOLOGY LA English DT Article DE eastern cottonwood; fructose; glucose; osmotic adjustment ID PRESSURE-VOLUME RELATIONSHIPS; WATER-STRESS TOLERANCE; OSMOTIC ADJUSTMENT; GRAIN-SORGHUM; OSMOREGULATION; DROUGHT; LEAVES; WHEAT; DEFICITS; SEASON AB We investigated effects of rehydration and time of sampling on solute accumulation in plants of two greenhouse-grown Populus deltoides Bartr. clones (Ohio Red and Platte) subjected to multiple cycles of water stress. Osmotic potential of leaves at full turgor was measured at predawn on well-watered (control) and water-stressed (conditioned) plants that had been rewatered the previous afternoon. Water-soluble organic solutes (carbohydrates, phenolic glucosides and organic acids) were determined at both predawn and midday, before and after rewatering. Conditioning resulted in solute accumulation; however, rewatering of conditioned plants decreased the predawn concentration of glucose by 19-35% and the total solute concentration by 14-15%, relative to values before rewatering. There was a 52% increase in salicin concentration in response to rewatering in conditioned plants of the Platte clone. In conditioned plants of both clones, the concentration of glucose was generally lower at midday than at predawn (16-47%), whereas the concentration of sucrose was higher at midday than at predawn (46-133%). Time of sampling was an important factor in determining whether conditioning resulted in accumulation of glucose and fructose. Compared with control plants, there was a significant accumulation of glucose and fructose at predawn and either no accumulation or a significant reduction of these solutes at midday both before and after rewatering of conditioned plants. Sampling time also affected the amount of solute that accumulated in response to conditioning. C1 UNIV NEBRASKA,DEPT FORESTRY FISHERIES & WILDLIFE,LINCOLN,NE 68583. UTAH STATE UNIV,DEPT FOREST RESOURCES,LOGAN,UT 84322. RP Gebre, GM (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. RI Kuhns, Michael/D-6956-2014 NR 23 TC 9 Z9 11 U1 0 U2 4 PU HERON PUBLISHING PI VICTORIA PA 202, 3994 SHELBOURNE ST, VICTORIA BC V8N 3E2, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD MAY PY 1997 VL 17 IS 5 BP 341 EP 346 PG 6 WC Forestry SC Forestry GA WX396 UT WOS:A1997WX39600008 ER PT J AU Hubbard, SS Rubin, Y Majer, E AF Hubbard, SS Rubin, Y Majer, E TI Ground-penetrating-radar-assisted saturation and permeability estimation in bimodal systems SO WATER RESOURCES RESEARCH LA English DT Article ID SOIL-WATER CONTENT; INVERSE PROBLEM; STOCHASTIC APPROACH; STEADY-STATE; FLOW; IDENTIFICATION; CONDUCTIVITY; INFORMATION; SIMULATIONS; VELOCITY AB Near-surface investigations often require characterization of vadose zone hydraulic parameters. Conventional sampling or borehole techniques for estimating these parameters are costly, time consuming, and invasive, all of which limit collection of hydrogeological data at a spacing needed for detailed site characterization. Incorporation of two- or three-dimensional densely sampled geophysical data with conventional hydrological data increases the amount of data available for the characterization and thus has the potential to significantly improve the hydraulic parameter estimates over those obtained from borehole data alone. The hydraulic estimation procedure can be greatly improved by incorporating dielectric information potentially available from ground penetrating radar (GPR), a noninvasive, high-resolution geophysical method. The procedures for collecting and processing GPR data in the format needed for the proposed estimation technique are relatively new and still a topic of research; our method requires as a starting point the ability to estimate dielectric constants from GPR data. Numerical experiments were performed to investigate the general utility of the GPR-assisted estimation technique under a range of conditions. Three bimodal systems were investigated, each system being composed of a sand facies together with another facies with a larger clay volume fraction; each facies was defined using characteristic values of clay content, porosity, and permeability. Using dielectric information and petrophysical relations, degree of saturation and intrinsic permeability values at each location within the three systems were identified. For bimodal systems, a dielectric constant measurement corresponds to two possible values of saturation and intrinsic permeability at each location; single values of saturation and intrinsic permeability were estimated from these values using the principle of maximum likelihood. Results from case studies demonstrate that a combination of GPR data with conventional borehole data significantly improves the estimates of saturation and has the potential to improve the estimates of permeability over those obtained from well bore data alone. The proposed method should be especially advantageous for vadose zone characterization in areas favorable for GPR data acquisition, where detailed hydraulic parameter information is required but the drilling of numerous boreholes is prohibited. C1 LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. RP Hubbard, SS (reprint author), UNIV CALIF BERKELEY,DEPT CIVIL & ENVIRONM ENGN,BERKELEY,CA 94720, USA. RI Hubbard, Susan/E-9508-2010 NR 66 TC 74 Z9 76 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAY PY 1997 VL 33 IS 5 BP 971 EP 990 DI 10.1029/96WR03979 PG 20 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA WX378 UT WOS:A1997WX37800006 ER PT J AU Murphy, EM Ginn, TR Chilakapati, A Resch, CT Phillips, JL Wietsma, TW Spadoni, CM AF Murphy, EM Ginn, TR Chilakapati, A Resch, CT Phillips, JL Wietsma, TW Spadoni, CM TI The influence of physical heterogeneity on microbial degradation and distribution in porous media SO WATER RESOURCES RESEARCH LA English DT Article ID IN-SITU BIOREMEDIATION; CONTAMINANT TRANSPORT; BICINCHONINIC ACID; BACTERIAL ADHESION; SOLUTE TRANSPORT; BEREA SANDSTONE; SANDY AQUIFER; BIODEGRADATION; GROUNDWATER; NUTRIENT AB Intermediate-scale experiments (meter-long, two-dimensional flow cell) were performed with aerobic biodegradation of benzoate substrate in physically heterogeneous (bimodal inclusive) media. Clastic heterogeneities were represented in a quasi-two-dimensional field, with low-conductivity inclusions embedded in a high-conductivity sandy matrix. The two media had similar pore-scale dispersivities but the conductivity ratio (similar to 1:50) incurred macrodispersive spreading in the longitudinal direction. The high-conductivity sand was uniformly inoculated with Pseudomonas cepacia sp., and a pulse input of substrate and chloride ion tracer were evaluated. Degradation and growth were oxygen-limited under nonlinear dual-Monod kinetics and controlled by spatial and temporal variations in nutrient flux. The low-conductivity inclusions created regions of slow transport that prolonged the dual availability of both oxygen and substrate, which in turn enhanced microbial growth in these regions. Bacterial detachment was significant, and the fivefold increase in biomass due to growth was entirely accounted for in the aqueous effluent which displayed a complicated nonlinear breakthrough curve. High-resolution deterministic modeling was applied to simulate the intermediate-scale experiment, with parameters of the relevant constitutive relations calibrated independently through batch and small-scale column experiments. Parameter fitting to match flow cell data was avoided. This approach was taken in order both to test the predictive modeling capability as it would necessarily be used in a field application and to avoid the a priori assumption that all relevant processes were adequately represented in the respective constitutive theories. Analyses of the fit between the independently calibrated model and the flow cell data were then used to isolate processes for further experimental study. This iterative experimental/modeling approach identified processes that contributed (surprisingly) to biodegradation in heterogeneous media and yet are not currently incorporated in most mathematical models: (1) buoyancy effects associated with very small solution density variations, amplified in heterogeneous media, and (2) dynamic biological processes associated with growth, namely, endogenous respiration, cell division partitioning to the aqueous phase, and active adhesion/detachment that are strongly coupled to the transport of dissolved nutrients or microorganisms. RP Murphy, EM (reprint author), PACIFIC NW LAB, ENVIRONM & ENERGY SCI DIV, POB 999, RICHLAND, WA 99352 USA. NR 61 TC 97 Z9 98 U1 1 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAY PY 1997 VL 33 IS 5 BP 1087 EP 1103 DI 10.1029/96WR03851 PG 17 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA WX378 UT WOS:A1997WX37800015 ER PT J AU Abreu, P Adam, W Adye, T Agasi, E Ajinenko, I Aleksan, R Alekseev, GD Alemany, R Allport, PP Almehed, S Amaldi, U Amato, S Andreazza, A Andrieux, ML Antilogus, P Apel, WD Arnoud, Y Asman, B Augustin, JE Augustinus, A Baillon, P Bambade, P Barao, F Barate, R Barbi, M Barbiellini, G Bardin, DY Baroncelli, A Barring, O Barrio, JA Bartl, W Bates, MJ Battaglia, M Baubillier, M Baudot, J Becks, KH Begalli, M Beilliere, P Belokopytov, Y Beloous, K Benvenuti, AC Berggren, M Bertrand, D Bianchi, F Bigi, M Bilenky, MS Billoir, P Bloch, D Blume, M Blyth, S Bolognese, T Bonesini, M Bonivento, W Booth, PSL Borisov, G Bosio, C Bosworth, S Botner, O Boudinov, E Bouquet, B Bourdarios, C Bowcock, TJV Bozzo, M Branchini, P Brand, KD Brenke, T Brenner, R Bricman, C Brillault, L Brown, RCA Bruckman, P Brunet, JM Bugge, L Buran, T Burgsmueller, T Buschmann, P Buys, A Cabrera, S Caccia, M Calvi, M Rozas, AJC Camporesi, T Canale, V Canepa, M Cankocak, K Cao, F Carena, F Carroll, L Caso, C Gimenez, MVC Cattai, A Cavallo, FR Cerrito, L Chabaud, V Charpentier, P Chaussard, L Chauveau, J Checchia, P Chelkov, GA Chen, M Chierici, R Chliapnikov, P Chochula, P Chorowicz, V Cindro, V Collins, P Contreras, JL Contri, R Cortina, E Cosme, G Cossutti, F Crawley, HB Crennell, D Crosetti, G Maestro, JC Czellar, S DahlJensen, E Dahm, J Dalmagne, B Dam, M Damgaard, G Dauncey, PD Davenport, M DaSilva, W Defoix, C Deghorain, A DellaRicca, G Delpierre, P Demaria, N DeAngelis, A DeBoer, W DeBrabandere, S DeClercq, C DelaVaissiere, C DeLotto, B DeMin, A DePaula, L DeSaintJean, C Dijkstra, H DiCiaccio, L Djama, F Dolbeau, J Donszelmann, M Doroba, K Dracos, M Drees, J Drees, KA Dris, M Dufour, Y Edsall, D Ehret, R Eigen, G Ekelof, T Ekspong, G Elsing, M Engel, JP Ershaidat, N Erzen, B Santo, ME Falk, E Fassouliotis, D Feindt, M Fenyuk, A Ferrer, A Filippas, TA Firestone, A Fischer, PA Foeth, H Fokitis, E Fontanelli, F Formenti, F Franek, B Frenkiel, P Fries, DC Frodesen, AG Fruhwirth, R FuldaQuenzer, F Fuster, J Galloni, A Gamba, D Gandelman, M Garcia, C Garcia, J Gaspar, C Gasparini, U Gavillet, P Gazis, EN Gele, D Gerber, JP Gerdyukov, L Gibbs, M Gokieli, R Golob, B Gopal, G Gorn, L Gorski, M Gouz, Y Gracco, V Graziani, E Grosdidier, G Grzelak, K Gumenyuk, S Gunnarsson, P Gunther, M Guy, J Hahn, F Hahn, S Hajduk, Z Hallgren, A Hamacher, K Hao, W Harris, FJ Hedberg, V Hernandez, JJ Herquet, P Herr, H Hessing, TL Higon, E Hilke, HJ Hill, TS Holmgren, SO Holt, PJ Holthuizen, D Hoorelbeke, S Houlden, M Huet, K Hultqvist, K Jackson, JN Jacobsson, R Jalocha, P Janik, R Jarlskog, C Jarlskog, G Jarry, P JeanMarie, B Johansson, EK Jonsson, L Jonsson, P Joram, C Juillot, P Kaiser, M Kapusta, F Karafasoulis, K Karlsson, M Karvelas, E Katsanevas, S Katsoufis, EC Keranen, R Khokhlov, Y Khomenko, BA Khovanski, NN King, B Kjaer, NJ Klein, H Klovning, A Kluit, P Koene, B Kokkinias, P Koratzinos, M Korcyl, K Kourkoumelis, C Kouznetsov, O Kramer, PH Krammer, M Kreuter, C Kronkvist, I Krumstein, Z Krupinski, W Kubinec, P Kucewicz, W Kurvinen, K Lacasta, C Laktineh, I Lamblot, S Lamsa, JW Lanceri, L Lane, DW Langefeld, P Last, I Laugier, JP Lauhakangas, R Leder, G Ledroit, F Lefebure, V Legan, CK Leitner, R Lemoigne, Y Lemonne, J Lenzen, G Lepeltier, V Lesiak, T Liko, D Lindner, R Lipniacka, A Lippi, I Loerstad, B Lokajicek, M Loken, JG Lopez, JM Loukas, D Lutz, P Lyons, L MacNaughton, J Maehlum, G Maio, A Malychev, V Mandl, F Marco, J Marco, R Marechal, B Margoni, M Marin, JC Mariotti, C Markou, A Maron, T MartinezRivero, C MartinezVidal, F MartiiGarcia, S Matorras, F Matteuzzi, C Matthiae, G Mazzucato, M McCubbin, M McKay, R McNulty, R Medbo, J Merk, M Meroni, C Meyer, S Meyer, WT Michelotto, M Migliore, E Mirabito, L Mitaroff, WA Mjoernmark, U Moa, T Moeller, R Moenig, K Monge, MR Morettini, P Mueller, H Mundim, LM Murray, WJ Muryn, B Myatt, G Naraghi, F Navarria, FL Navas, S Nawrocki, K Negri, P Nemecek, S Neumann, W Neumeister, N Nicolaidou, R Nielsen, BS Nieuwenhuizen, M Nikolaenko, V Niss, P Nomerotski, A Normand, A OberschulteBeckmann, W Obraztsov, V Olshevski, AG Onofre, A Orava, R Osterberg, K Ouraou, A Paganini, P Paganoni, M Pages, P Palka, H Papadopoulou, TD Papageorgiou, K Pape, L Parkes, C Parodi, F Passeri, A Pegoraro, M Peralta, L Pernegger, H Pernicka, M Perrotta, A Petridou, C Petrolini, A Petrovyck, M Phillips, HT Piana, G Pierre, F Pimenta, M Pindo, M Plaszczynski, S Podobrin, O Pol, ME Polok, G Poropat, P Pozdniakov, V Prest, M Privitera, P Pukhaeva, N PUllia, A Radojicic, D Ragazzi, S Rahmani, H Rames, J Ratoff, PN Read, AL Reale, M Rebecchi, P Redaelli, NG Regler, M Reid, D Renton, PB Resvanis, LK Richard, F Richardson, J Ridky, J Rinaudo, G Ripp, I Romero, A Roncagliolo, I Ronchese, P Roos, L Rosenberg, EI Rosso, E Roudeau, P Rovelli, T Ruckstuhl, W RuhlmannKleider, V Ruiz, A Rybicki, K Saarikko, H Sacquin, Y Sadovsky, A Sajot, G Salt, J Sanchez, J Sannino, M Schimmelpfennig, M Schneider, H Schwickerath, U Schyns, MAE Sciolla, G Scuri, F Seager, P Sedykh, Y Segar, AM Seitz, A Sekulin, R Shellard, RC Siccama, I Siegrist, P Simonetti, S Simonetto, F Sisakian, AN Sitar, B Skaali, TB Smadja, G Smirnov, N Smirnova, O Smith, GR Solovianov, O Sosnowski, R SouzaSantos, D Spassov, T Spiriti, E Sponholz, P Squarcia, S Stanescu, C Stapnes, S Stavitski, I Stichelbaut, F Stocchi, A Strauss, J Strub, R Stugu, B Szczekowski, M Szeptycka, M Tabarelli, T Tavernet, JP Tchikilev, O Tilquin, A Timmermans, J Tkatchev, LG Todorov, T Toet, DZ Tomaradze, A Tome, B Tonazzo, A Tortora, L Transtromer, G Treille, D Trischuk, W Tristram, G Trombini, A Troncon, C Tsirou, A Turluer, ML Tyapkin, IA Tyndel, M Tzamarias, S Ueberschaer, B Ullaland, O Urarov, V Valenti, G Vallazza, E VanderVelde, C VanApeldoorn, GW VanDam, P VanDoninck, WK VanEldik, J Vassilopoulos, N Vegni, G Ventura, L Venus, W Verbeure, F Verlato, M Vertogradov, LS Vilanova, D Vincent, P Vitale, L Vlasov, E Vodopyanov, AS Vrba, V Wahlen, H Walck, C Weierstall, M Weilhammer, P Weiser, C Wetherell, AM Wicke, D Wickens, JH Wielers, M Wilkinson, GR Williams, WSC Winter, M Witek, M Woschnagg, K Yip, K Yushchenko, O Zach, F Zaitsev, A Zalewska, A Zalewski, P Zavrtanik, D Zevgolatakos, E Zimin, NI Zito, M Zontar, D Zuberi, R Zucchelli, GC Zumerle, G AF Abreu, P Adam, W Adye, T Agasi, E Ajinenko, I Aleksan, R Alekseev, GD Alemany, R Allport, PP Almehed, S Amaldi, U Amato, S Andreazza, A Andrieux, ML Antilogus, P Apel, WD Arnoud, Y Asman, B Augustin, JE Augustinus, A Baillon, P Bambade, P Barao, F Barate, R Barbi, M Barbiellini, G Bardin, DY Baroncelli, A Barring, O Barrio, JA Bartl, W Bates, MJ Battaglia, M Baubillier, M Baudot, J Becks, KH Begalli, M Beilliere, P Belokopytov, Y Beloous, K Benvenuti, AC Berggren, M Bertrand, D Bianchi, F Bigi, M Bilenky, MS Billoir, P Bloch, D Blume, M Blyth, S Bolognese, T Bonesini, M Bonivento, W Booth, PSL Borisov, G Bosio, C Bosworth, S Botner, O Boudinov, E Bouquet, B Bourdarios, C Bowcock, TJV Bozzo, M Branchini, P Brand, KD Brenke, T Brenner, R Bricman, C Brillault, L Brown, RCA Bruckman, P Brunet, JM Bugge, L Buran, T Burgsmueller, T Buschmann, P Buys, A Cabrera, S Caccia, M Calvi, M Rozas, AJC Camporesi, T Canale, V Canepa, M Cankocak, K Cao, F Carena, F Carroll, L Caso, C Gimenez, MVC Cattai, A Cavallo, FR Cerrito, L Chabaud, V Charpentier, P Chaussard, L Chauveau, J Checchia, P Chelkov, GA Chen, M Chierici, R Chliapnikov, P Chochula, P Chorowicz, V Cindro, V Collins, P Contreras, JL Contri, R Cortina, E Cosme, G Cossutti, F Crawley, HB Crennell, D Crosetti, G Maestro, JC Czellar, S DahlJensen, E Dahm, J Dalmagne, B Dam, M Damgaard, G Dauncey, PD Davenport, M DaSilva, W Defoix, C Deghorain, A DellaRicca, G Delpierre, P Demaria, N DeAngelis, A DeBoer, W DeBrabandere, S DeClercq, C DelaVaissiere, C DeLotto, B DeMin, A DePaula, L DeSaintJean, C Dijkstra, H DiCiaccio, L Djama, F Dolbeau, J Donszelmann, M Doroba, K Dracos, M Drees, J Drees, KA Dris, M Dufour, Y Edsall, D Ehret, R Eigen, G Ekelof, T Ekspong, G Elsing, M Engel, JP Ershaidat, N Erzen, B Santo, ME Falk, E Fassouliotis, D Feindt, M Fenyuk, A Ferrer, A Filippas, TA Firestone, A Fischer, PA Foeth, H Fokitis, E Fontanelli, F Formenti, F Franek, B Frenkiel, P Fries, DC Frodesen, AG Fruhwirth, R FuldaQuenzer, F Fuster, J Galloni, A Gamba, D Gandelman, M Garcia, C Garcia, J Gaspar, C Gasparini, U Gavillet, P Gazis, EN Gele, D Gerber, JP Gerdyukov, L Gibbs, M Gokieli, R Golob, B Gopal, G Gorn, L Gorski, M Gouz, Y Gracco, V Graziani, E Grosdidier, G Grzelak, K Gumenyuk, S Gunnarsson, P Gunther, M Guy, J Hahn, F Hahn, S Hajduk, Z Hallgren, A Hamacher, K Hao, W Harris, FJ Hedberg, V Hernandez, JJ Herquet, P Herr, H Hessing, TL Higon, E Hilke, HJ Hill, TS Holmgren, SO Holt, PJ Holthuizen, D Hoorelbeke, S Houlden, M Huet, K Hultqvist, K Jackson, JN Jacobsson, R Jalocha, P Janik, R Jarlskog, C Jarlskog, G Jarry, P JeanMarie, B Johansson, EK Jonsson, L Jonsson, P Joram, C Juillot, P Kaiser, M Kapusta, F Karafasoulis, K Karlsson, M Karvelas, E Katsanevas, S Katsoufis, EC Keranen, R Khokhlov, Y Khomenko, BA Khovanski, NN King, B Kjaer, NJ Klein, H Klovning, A Kluit, P Koene, B Kokkinias, P Koratzinos, M Korcyl, K Kourkoumelis, C Kouznetsov, O Kramer, PH Krammer, M Kreuter, C Kronkvist, I Krumstein, Z Krupinski, W Kubinec, P Kucewicz, W Kurvinen, K Lacasta, C Laktineh, I Lamblot, S Lamsa, JW Lanceri, L Lane, DW Langefeld, P Last, I Laugier, JP Lauhakangas, R Leder, G Ledroit, F Lefebure, V Legan, CK Leitner, R Lemoigne, Y Lemonne, J Lenzen, G Lepeltier, V Lesiak, T Liko, D Lindner, R Lipniacka, A Lippi, I Loerstad, B Lokajicek, M Loken, JG Lopez, JM Loukas, D Lutz, P Lyons, L MacNaughton, J Maehlum, G Maio, A Malychev, V Mandl, F Marco, J Marco, R Marechal, B Margoni, M Marin, JC Mariotti, C Markou, A Maron, T MartinezRivero, C MartinezVidal, F MartiiGarcia, S Matorras, F Matteuzzi, C Matthiae, G Mazzucato, M McCubbin, M McKay, R McNulty, R Medbo, J Merk, M Meroni, C Meyer, S Meyer, WT Michelotto, M Migliore, E Mirabito, L Mitaroff, WA Mjoernmark, U Moa, T Moeller, R Moenig, K Monge, MR Morettini, P Mueller, H Mundim, LM Murray, WJ Muryn, B Myatt, G Naraghi, F Navarria, FL Navas, S Nawrocki, K Negri, P Nemecek, S Neumann, W Neumeister, N Nicolaidou, R Nielsen, BS Nieuwenhuizen, M Nikolaenko, V Niss, P Nomerotski, A Normand, A OberschulteBeckmann, W Obraztsov, V Olshevski, AG Onofre, A Orava, R Osterberg, K Ouraou, A Paganini, P Paganoni, M Pages, P Palka, H Papadopoulou, TD Papageorgiou, K Pape, L Parkes, C Parodi, F Passeri, A Pegoraro, M Peralta, L Pernegger, H Pernicka, M Perrotta, A Petridou, C Petrolini, A Petrovyck, M Phillips, HT Piana, G Pierre, F Pimenta, M Pindo, M Plaszczynski, S Podobrin, O Pol, ME Polok, G Poropat, P Pozdniakov, V Prest, M Privitera, P Pukhaeva, N PUllia, A Radojicic, D Ragazzi, S Rahmani, H Rames, J Ratoff, PN Read, AL Reale, M Rebecchi, P Redaelli, NG Regler, M Reid, D Renton, PB Resvanis, LK Richard, F Richardson, J Ridky, J Rinaudo, G Ripp, I Romero, A Roncagliolo, I Ronchese, P Roos, L Rosenberg, EI Rosso, E Roudeau, P Rovelli, T Ruckstuhl, W RuhlmannKleider, V Ruiz, A Rybicki, K Saarikko, H Sacquin, Y Sadovsky, A Sajot, G Salt, J Sanchez, J Sannino, M Schimmelpfennig, M Schneider, H Schwickerath, U Schyns, MAE Sciolla, G Scuri, F Seager, P Sedykh, Y Segar, AM Seitz, A Sekulin, R Shellard, RC Siccama, I Siegrist, P Simonetti, S Simonetto, F Sisakian, AN Sitar, B Skaali, TB Smadja, G Smirnov, N Smirnova, O Smith, GR Solovianov, O Sosnowski, R SouzaSantos, D Spassov, T Spiriti, E Sponholz, P Squarcia, S Stanescu, C Stapnes, S Stavitski, I Stichelbaut, F Stocchi, A Strauss, J Strub, R Stugu, B Szczekowski, M Szeptycka, M Tabarelli, T Tavernet, JP Tchikilev, O Tilquin, A Timmermans, J Tkatchev, LG Todorov, T Toet, DZ Tomaradze, A Tome, B Tonazzo, A Tortora, L Transtromer, G Treille, D Trischuk, W Tristram, G Trombini, A Troncon, C Tsirou, A Turluer, ML Tyapkin, IA Tyndel, M Tzamarias, S Ueberschaer, B Ullaland, O Urarov, V Valenti, G Vallazza, E VanderVelde, C VanApeldoorn, GW VanDam, P VanDoninck, WK VanEldik, J Vassilopoulos, N Vegni, G Ventura, L Venus, W Verbeure, F Verlato, M Vertogradov, LS Vilanova, D Vincent, P Vitale, L Vlasov, E Vodopyanov, AS Vrba, V Wahlen, H Walck, C Weierstall, M Weilhammer, P Weiser, C Wetherell, AM Wicke, D Wickens, JH Wielers, M Wilkinson, GR Williams, WSC Winter, M Witek, M Woschnagg, K Yip, K Yushchenko, O Zach, F Zaitsev, A Zalewska, A Zalewski, P Zavrtanik, D Zevgolatakos, E Zimin, NI Zito, M Zontar, D Zuberi, R Zucchelli, GC Zumerle, G TI Search for new phenomena using single photon events at LEP1 SO ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS LA English DT Article ID DENSITY PROJECTION CHAMBER; RADIATIVE BHABHA SCATTERING; EXCITED NEUTRINOS; INVISIBLE WIDTH; E+E COLLISIONS; Z0 DECAYS; E+E-->NU-NU-BAR-GAMMA; DISTRIBUTIONS; LEPTON; NUMBER AB Data are presented on the reaction e(+)e(-) --> gamma + no other detected particle at centre-of-mass energies of 89.48, 91.26 and 93.08 GeV. The cross-section for this reaction is related directly to the number of light neutrino generations which couple to the Z(0) boson, and to several other possible phenomena such as the production of excited neutrinos, the production of any invisible 'X' particle, and the magnetic moment of the tau neutrino. Based on the observed number of single photon events, the number of light neutrinos that couple to the Z(0) is measured to be N-nu = 2.89 +/- 0.38. No evidence is found for anomalous production of energetic single photons, and upper limits at 95% confidence level are determined for excited neutrino production (BR < 4 - 8 x 10(-6) depending on its mass), production of an invisible 'X' particle (sigma < 0.1 pb for masses below 60 GeV), and the magnetic moment of the tall neutrino (< 5.1 x 10(-6) mu(B)). C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. UNIV INSTELLING ANTWERP,DEPT PHYS,B-2610 WILRIJK,BELGIUM. FREE UNIV BRUSSELS,IIHE,B-1050 BRUSSELS,BELGIUM. UNIV MONS,FAC SCI,B-7000 MONS,BELGIUM. UNIV ATHENS,PHYS LAB,GR-10680 ATHENS,GREECE. UNIV BERGEN,DEPT PHYS,N-5007 BERGEN,NORWAY. UNIV BOLOGNA,DIPARTIMENTO FIS,I-40126 BOLOGNA,ITALY. IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. CTR BRASILEIRO PESQUISAS FIS,BR-22290 RIO JANEIRO,BRAZIL. PONTIFICIA UNIV CATOLICA RIO DE JANEIRO,DEPT FIS,BR-22453 RIO JANEIRO,BRAZIL. UNIV ESTADUAL RIO DE JANEIRO,INST FIS,RIO JANEIRO,BRAZIL. COMENIUS UNIV BRATISLAVA,FAC MATH & PHYS,SK-84215 BRATISLAVA,SLOVAKIA. COLL FRANCE,IN2P3,PHYS CORPUSCULAIRE LAB,CNRS,F-75231 PARIS 05,FRANCE. CERN,CH-1211 GENEVA 23,SWITZERLAND. UNIV STRASBOURG 1,IN2P3,CTR RECH NUCL,CNRS,F-67037 STRASBOURG,FRANCE. NATL CTR SCI RES DEMOKRITOS,INST NUCL PHYS,GR-15310 ATHENS,GREECE. ACAD SCI CZECH REPUBL,INST PHYS,FZU,DIV HIGH ENERGY PHYS,CZ-18040 PRAGUE 8,CZECH REPUBLIC. UNIV GENOA,DIPARTIMENTO FIS,I-16146 GENOA,ITALY. IST NAZL FIS NUCL,I-16146 GENOA,ITALY. UNIV GRENOBLE 1,IN2P3,INST SCI NUCL,CNRS,F-38026 GRENOBLE,FRANCE. RES INST HIGH ENERGY PHYS,SEFT,FIN-00014 HELSINKI,FINLAND. JOINT INST NUCL RES,MOSCOW 101000,RUSSIA. UNIV KARLSRUHE,INST EXPT KERNPHYS,D-76128 KARLSRUHE,GERMANY. INST NUCL PHYS,PL-30055 KRAKOW,POLAND. UNIV MIN & MET KRAKOW,PL-30055 KRAKOW,POLAND. UNIV PARIS 11,IN2P3,LAB ACCELERATEUR LINEAIRE,CNRS,F-91405 ORSAY,FRANCE. UNIV LANCASTER,SCH PHYS & MAT,LANCASTER LA1 4YB,ENGLAND. UNIV LIVERPOOL,DEPT PHYS,LIVERPOOL L69 3BX,MERSEYSIDE,ENGLAND. UNIV PARIS 06,IN2P3,LPNHE,CNRS,F-75252 PARIS 05,FRANCE. UNIV PARIS 07,IN2P3,LPNHE,CNRS,F-75252 PARIS 05,FRANCE. LUND UNIV,DEPT PHYS,S-22363 LUND,SWEDEN. UNIV LYON 1,IPNL,IN2P3,CNRS,F-69622 VILLEURBANNE,FRANCE. UNIV COMPLUTENSE MADRID,E-28040 MADRID,SPAIN. UNIV AIX MARSEILLE 2,IN2P3,CPP,CNRS,F-13288 MARSEILLE 09,FRANCE. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. IST NAZL FIS NUCL,I-20133 MILAN,ITALY. NIELS BOHR INST,DK-2100 COPENHAGEN O,DENMARK. CHARLES UNIV,MFF,NUCL CTR,NC,CR-18000 PRAGUE 8,CZECH REPUBLIC. NIKHEF H,NL-1009 DB AMSTERDAM,NETHERLANDS. NATL TECH UNIV ATHENS,DEPT PHYS,GR-15773 ATHENS,GREECE. UNIV OSLO,DEPT PHYS,N-1000 OSLO 3,NORWAY. UNIV OVIEDO,DEPT FIS,OVIEDO 33006,SPAIN. UNIV OXFORD,DEPT PHYS,OXFORD OX1 3RH,ENGLAND. UNIV PADUA,DIPARTIMENTO FIS,I-35131 PADUA,ITALY. IST NAZL FIS NUCL,I-35131 PADUA,ITALY. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,I-00173 ROME,ITALY. IST NAZL FIS NUCL,I-00173 ROME,ITALY. CENS,DSM,DAPNIA,F-91191 GIF SUR YVETTE,FRANCE. IST NAZL FIS NUCL,IST SUPER SANITA,I-00161 ROME,ITALY. UNIV CANTABRIA,CSIC,INST FIS CANTABIRA,SANTANDER 39006,SPAIN. INST HIGH ENERGY PHYS,PROTVINO,MOSCOW REGION,RUSSIA. UNIV LJUBLJANA,JOZEF STEFAN INST,LJUBLJANA 61000,SLOVENIA. UNIV LJUBLJANA,DEPT PHYS,LJUBLJANA 61000,SLOVENIA. UNIV STOCKHOLM,S-11385 STOCKHOLM,SWEDEN. UNIV TURIN,DIPARTIMENTO FIS SPERIMENTALE,I-10125 TURIN,ITALY. IST NAZL FIS NUCL,I-10125 TURIN,ITALY. UNIV TRIESTE,DIPARTIMENTO FIS,I-34127 TRIESTE,ITALY. IST NAZL FIS NUCL,I-34127 TRIESTE,ITALY. UNIV UDINE,IST FIS,I-33100 UDINE,ITALY. UNIV FED RIO DE JANEIRO,BR-21945970 RIO JANEIRO,BRAZIL. UNIV UPPSALA,DEPT RADIAT SCI,S-75121 UPPSALA,SWEDEN. UNIV VALENCIA,DFAMN,E-46100 BURJASSOT,VALENCIA,SPAIN. CSIC,IFIC,E-46100 BURJASSOT,VALENCIA,SPAIN. AUSTRIAN ACAD SCI,INST HOCHENERGIEPHYS,A-1050 VIENNA,AUSTRIA. INST NUCL STUDIES,PL-00681 WARSAW,POLAND. UNIV WARSAW,PL-00681 WARSAW,POLAND. BERG UNIV GESAMTHSCH WUPPERTAL,FACHBEREICH PHYS,D-42097 WUPPERTAL 1,GERMANY. RP Abreu, P (reprint author), INST SUPER TECN,FCUL,LIP,AV ELIAS GARCIA 14-1,P-1000 LISBON,PORTUGAL. RI Espirito Santo, Maria Catarina/L-2341-2014; Pimenta, Mario/M-1741-2013; gandelman, miriam/N-3739-2014; Ragazzi, Stefano/D-2463-2009; Cabrera Urban, Susana/H-1376-2015; Matorras, Francisco/I-4983-2015; Ferrer, Antonio/H-2942-2015; Rovelli, Tiziano/K-4432-2015; Della Ricca, Giuseppe/B-6826-2013; Olshevskiy, Alexander/I-1580-2016; Rames, Jiri/H-2450-2014; Paganoni, Marco/A-4235-2016; Dracos, Marcos/K-2335-2012; Michelotto, Michele/A-9571-2013; Hallgren, Allan/A-8963-2013; Botner, Olga/A-9110-2013; Mundim, Luiz/A-1291-2012; Yip, Kin/D-6860-2013; Zalewski, Piotr/H-7335-2013; Monge, Maria Roberta/G-9127-2012; Nemecek, Stanislav/G-5931-2014; Ridky, Jan/H-6184-2014; Tome, Bernardo/J-4410-2013; Fernandez, Ester/K-9734-2014; Nomerotski, Andrei/A-5169-2010; Andreazza, Attilio/E-5642-2011; Verlato, Marco/J-4604-2012; Katsanevas, Stavros/A-4297-2011; Ruiz, Alberto/E-4473-2011; Marti-Garcia, Salvador/F-3085-2011; branchini, paolo/A-4857-2011; Krammer, Manfred/A-6508-2010; De Saint Jean, Cyrille/E-8853-2011; Shellard, Ronald/G-4825-2012; Petrolini, Alessandro/H-3782-2011; Fruhwirth, Rudolf/H-2529-2012; Contreras Gonzalez, Jose Luis/K-7255-2014; Hernandez-Rey, Juan Jose/N-5955-2014; Abreu, Pedro/L-2220-2014; Navas, Sergio/N-4649-2014; Barao, Fernando/O-2357-2016; Barrio, Juan/L-3227-2014; Zaitsev, Alexandre/B-8989-2017; OI Tabarelli de Fatis, Tommaso/0000-0001-6262-4685; Lacasta, Carlos/0000-0002-2623-6252; DE MIN, ALBERTO/0000-0002-8130-9389; Demaria, Natale/0000-0003-0743-9465; Sannino, Mario/0000-0001-7700-8383; Maio, Amelia/0000-0001-9099-0009; De Angelis, Alessandro/0000-0002-3288-2517; PREST, MICHELA/0000-0003-3161-4454; De Lotto, Barbara/0000-0003-3624-4480; Espirito Santo, Maria Catarina/0000-0003-1286-7288; Pimenta, Mario/0000-0002-2590-0908; Ragazzi, Stefano/0000-0001-8219-2074; Matorras, Francisco/0000-0003-4295-5668; Ferrer, Antonio/0000-0003-0532-711X; Rovelli, Tiziano/0000-0002-9746-4842; Della Ricca, Giuseppe/0000-0003-2831-6982; Olshevskiy, Alexander/0000-0002-8902-1793; Paganoni, Marco/0000-0003-2461-275X; Dracos, Marcos/0000-0003-0514-193X; Michelotto, Michele/0000-0001-6644-987X; Mundim, Luiz/0000-0001-9964-7805; Yip, Kin/0000-0002-8576-4311; Monge, Maria Roberta/0000-0003-1633-3195; Ridky, Jan/0000-0001-6697-1393; Tome, Bernardo/0000-0002-7564-8392; Andreazza, Attilio/0000-0001-5161-5759; Verlato, Marco/0000-0003-1967-7655; Ruiz, Alberto/0000-0002-3639-0368; Krammer, Manfred/0000-0003-2257-7751; Shellard, Ronald/0000-0002-2983-1815; Petrolini, Alessandro/0000-0003-0222-7594; Contreras Gonzalez, Jose Luis/0000-0001-7282-2394; Hernandez-Rey, Juan Jose/0000-0002-1527-7200; Abreu, Pedro/0000-0002-9973-7314; Navas, Sergio/0000-0003-1688-5758; Barao, Fernando/0000-0002-8346-9941; Barrio, Juan/0000-0002-0965-0259; Zaitsev, Alexandre/0000-0002-4961-8368; Matteuzzi, Clara/0000-0002-4047-4521 NR 47 TC 38 Z9 38 U1 0 U2 9 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0170-9739 J9 Z PHYS C PART FIELDS JI Z. Phys. C-Part. Fields PD MAY PY 1997 VL 74 IS 4 BP 577 EP 586 DI 10.1007/s002880050421 PG 10 WC Physics, Particles & Fields SC Physics GA XD666 UT WOS:A1997XD66600001 ER PT J AU Kampert, KH Awes, TC Stankus, P Gutbrod, HH Manko, V Peitzmann, T Santo, R AF Kampert, KH Awes, TC Stankus, P Gutbrod, HH Manko, V Peitzmann, T Santo, R TI Search for direct photons from S-Au collisions at 200 GeV/nucleon by the CERES collaboration - Comment SO ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS LA English DT Editorial Material AB In this note we comment on a recent publication in this journal by the CERES (NA45) Collaboration [1]. The authors report to have determined an upper limit on the direct photon yield relative to the decay photon yield in S + Au collisions of 14% and 7% by two different methods, respectively. We argue that these limits are unsupported by the results and analysis of the CERES data. The systematic error estimates quoted in the CERES analysis are consistently overly optimistic. Using more realistic estimates of the various error contributions and propagating them appropriately we arrive at a direct photon upper limit which at best is 20% of the inclusive photon yield, and most probably is much higher. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. ECOLE MINES,SUBATECH,F-44070 NANTES,FRANCE. IV KURCHATOV ATOM ENERGY INST,RES CTR,MOSCOW 123182,RUSSIA. UNIV MUNSTER,INST KERNPHYS,D-48149 MUNSTER,GERMANY. RP Kampert, KH (reprint author), UNIV KARLSRUHE TH,INST EXPT KERNPHYS,D-76131 KARLSRUHE,GERMANY. RI Peitzmann, Thomas/K-2206-2012; OI Peitzmann, Thomas/0000-0002-7116-899X; Kampert, Karl-Heinz/0000-0002-2805-0195 NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0170-9739 J9 Z PHYS C PART FIELDS JI Z. Phys. C-Part. Fields PD MAY PY 1997 VL 74 IS 4 BP 587 EP 591 DI 10.1007/s002880050422 PG 5 WC Physics, Particles & Fields SC Physics GA XD666 UT WOS:A1997XD66600002 ER PT J AU Baur, R Breskin, A Chechik, R Drees, A Jacob, C Faschingbauer, U Fischer, P Fraenkel, Z Gatti, E Glassel, P Gunzel, T DelosHeros, CP Hess, F Irmscher, D Lenkeit, B Olsen, LH Panebrattsev, Y Pfeiffer, A Ravinovich, I Rehak, P Schon, A Schukraft, J Sampietro, M Shor, A Specht, HJ Steiner, V Tapprogge, S TelZur, G Tserruya, I Ullrich, T Wurm, JP AF Baur, R Breskin, A Chechik, R Drees, A Jacob, C Faschingbauer, U Fischer, P Fraenkel, Z Gatti, E Glassel, P Gunzel, T DelosHeros, CP Hess, F Irmscher, D Lenkeit, B Olsen, LH Panebrattsev, Y Pfeiffer, A Ravinovich, I Rehak, P Schon, A Schukraft, J Sampietro, M Shor, A Specht, HJ Steiner, V Tapprogge, S TelZur, G Tserruya, I Ullrich, T Wurm, JP TI Direct photon search by the CERES-Collaboration - Reply SO ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS LA English DT Editorial Material C1 MAX PLANCK INST KERNPHYS,D-69117 HEIDELBERG,GERMANY. WEIZMANN INST SCI,IL-76100 REHOVOT,ISRAEL. POLITECN MILAN,I-20133 MILAN,ITALY. BROOKHAVEN NATL LAB,UPTON,NY 11973. CERN,CH-1211 GENEVA 23,SWITZERLAND. RP Baur, R (reprint author), UNIV HEIDELBERG,INST PHYS,D-69120 HEIDELBERG,GERMANY. RI BRESKIN, AMOS/K-1549-2012; Sampietro, Marco/A-3732-2016 OI Sampietro, Marco/0000-0003-4825-9612 NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0170-9739 J9 Z PHYS C PART FIELDS JI Z. Phys. C-Part. Fields PD MAY PY 1997 VL 74 IS 4 BP 593 EP 594 DI 10.1007/s002880050423 PG 2 WC Physics, Particles & Fields SC Physics GA XD666 UT WOS:A1997XD66600003 ER PT J AU Olson, DH Zygmunt, SA Erhardt, MK Curtiss, LA Iton, LE AF Olson, DH Zygmunt, SA Erhardt, MK Curtiss, LA Iton, LE TI Evidence for dimeric and tetrameric water clusters in HZSM-5 SO ZEOLITES LA English DT Article ID ZEOLITES; ADSORPTION; METHANOL AB Temperature-programmed desorption shows that water desorbs from HZSM-5 (Si/Al = 13) . nH(2)O in a two-step process. The amount of water evolved at each step corresponds to about two H2O per acidic proton, indicating that the tetrameric cluster formed at full loading consists of a strongly bound pair and a weakly bound pair of water molecules. Quantum mechanical studies using cluster models of aluminosilicate systems indicate that the desorption energies for the first and second water molecules of a dimer adsorbed at the acid site are 9.7 and 12.6 kcal/mol, respectively. These values are within the energy resolution of the TPD experiment and are consistent with both water molecules from the dimer seeming to desorb simultaneously. Evidence for a tetramer is consistent with earlier findings on dealuminated mordenites. (C) Elsevier Science Inc. 1997. C1 VALPARAISO UNIV, DEPT PHYS & ASTRON, VALPARAISO, IN 46383 USA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. RP Olson, DH (reprint author), UNIV PENN, DEPT CHEM ENGN, 220 S 33RD ST, 311A TOWNE BLDG, PHILADELPHIA, PA 19104 USA. NR 15 TC 15 Z9 16 U1 1 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0144-2449 J9 ZEOLITES JI Zeolites PD MAY-JUN PY 1997 VL 18 IS 5-6 BP 347 EP 349 DI 10.1016/S0144-2449(97)00024-9 PG 3 WC Chemistry, Physical SC Chemistry GA XK612 UT WOS:A1997XK61200005 ER PT J AU Schiferl, SK Maudlin, PJ AF Schiferl, SK Maudlin, PJ TI Evolution of plastic anisotropy for high-strain-rate computations SO COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING LA English DT Article ID YIELD SURFACE; DEFORMATION; ALGORITHM; ROTATION; TITANIUM AB A model for anisotropic material strength, and for changes in the anisotropy due to plastic strain, is described. This model has been developed for use in high-rate, explicit, Lagrangian multidimensional continuum-mechanics codes. The model handles anisotropies in single-phase materials, in particular the anisotropies due to crystallographic texture-preferred orientations of the single-crystal grains. Textural anisotropies, and the changes in these anisotropies, depend overwhelmingly on the crystal structure of the material and on the deformation history. The changes, particularly for complex deformations, are not amenable to simple analytical forms. To handle this problem, the material model described here includes a texture code, or micromechanical calculation, coupled to a continuum code. The texture code updates grain orientations as a function of tensor plastic strain, and calculates the yield strength in different directions. A yield function is fitted to these yield 'points'. For each computational cell in the continuum simulation, the texture code tracks a particular set of grain orientations. The orientations will change due to the tensor strain history, and the yield function will change accordingly. Hence, the continuum code supplies a tensor strain to the texture code, and the texture code supplies an updated yield function to the continuum code. Since significant texture changes require relatively large strains-typically, a few percent or more-the texture code is not called very often, and the increase in computer time is not excessive. The model was implemented, using a finite-element continuum code and a texture code specialized for hexagonal-close-packed crystal structures. The results for several uniaxial stress problems and an explosive-forming problem are shown. RP LOS ALAMOS NATL LAB, GRP XNH, MAIL STOP F664, LOS ALAMOS, NM 87545 USA. NR 35 TC 6 Z9 6 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0045-7825 EI 1879-2138 J9 COMPUT METHOD APPL M JI Comput. Meth. Appl. Mech. Eng. PD APR 30 PY 1997 VL 143 IS 3-4 BP 249 EP 270 DI 10.1016/S0045-7825(96)01159-0 PG 22 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA WY493 UT WOS:A1997WY49300003 ER PT J AU Eliason, DE Bourgeois, AJ AF Eliason, DE Bourgeois, AJ TI Validation of numerical shallow water models for stratified seiches SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE shallow water equations; seiches; stratification; analytical solution; validation AB A new analytical solution is presented for the case of a stratified seiche. This solution, especially its energetics, is useful for the validation of numerical shallow water models under stratified conditions. The utility of the analytical solution for validation is shown by using it to validate a simple finite difference numerical model. A comparison of the energetics of the numerical and analytical solutions reveals that the model results converge rapidly to the analytical solution with increasing resolution, such that a grid size of 30 x 30 would appear adequate for validation. In addition to properly resolving the spatial features, good temporal resolution is also necessary for validation, i.e use of a Courant number (Cr) less than one. For example, owing to the numerical dispersion of the present model, using Cr = 5/4 rather than Cr = 1/4 for the 50 x 50 grid resulted in 36 times larger RMS errors of model versus analytical barotropic available potential energy. This new analytical solution should be applied to a test suite of such validation tools before using such numerical models to simulate the more realistic geophysical flows encountered in lakes, bays, harbours and semienclosed seas under stratified conditions. (C) 1997 by John Wiley & Sons, Ltd. C1 US EPA,RES TRIANGLE PK,NC 27711. RP Eliason, DE (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV ATMOSPHER SCI,POB 808,LIVERMORE,CA 94551, USA. NR 9 TC 4 Z9 4 U1 1 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD APR 30 PY 1997 VL 24 IS 8 BP 771 EP 786 DI 10.1002/(SICI)1097-0363(19970430)24:8<771::AID-FLD481>3.3.CO;2-9 PG 16 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA WV644 UT WOS:A1997WV64400003 ER PT J AU Christe, KO Dixon, DA Schrobilgen, GJ Wilson, WW AF Christe, KO Dixon, DA Schrobilgen, GJ Wilson, WW TI Tetrafluorophosphate anion SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID NMR CHEMICAL-SHIFTS; BASIS-SETS; MAGNETIC-SUSCEPTIBILITIES; MOLECULAR CALCULATIONS; LOCALIZED QUANTITIES; VIBRATIONAL-SPECTRA; PERTURBATION-THEORY; WAVE-FUNCTIONS; DENSITY; FLUORIDE AB The elusive POF4- anion has been characterized for the first time. It is formed from N(CH3)(4)F and POF3 in CHF3 solution at -140 degrees C and can be observed at this temperature by F-19 and P-31 NMR spectroscopy. Between -140 and -100 degrees C it reacts with POS forming the OF2P-O-PF5- anion, which, at higher temperatures, reacts with F- anions to give PO2F2- and PF6-. This reaction sequence provides a low activation energy barrier pathway for the highly exothermic dismutation of pseudo-trigonal-bipyramidal POF4- to tetrahedral PO2F2- and octahedral PF6- and explains the previous failures to isolate POF4- salts. In addition to POF4-, OF2POPF5-, and PO2F2-, the protonated form of OF2POPF5-, i.e., HOF2POPF5, was also identified as a byproduct by NMR spectroscopy. The structure, vibrational spectra, force field, NMR parameters, and dismutation energy of POF4- were calculated by nb initio electronic structure methods using, where required, the closely related and well-known PF4- ion and POF3, PF3, SOF4, and SF4 molecules for the determination of scaling factors. Although the structures and dismutation energies of isoelectronic POF4- and SOF4 are very similar, their dismutation behavior is strikingly different. While POF4- dismutates rapidly at low temperatures, SOF4 is kinetically stable toward dismutation to SO2F2 and SF6. This fact is attributed to the lack of a low activation energy barrier pathway for SOF(4)7. Furthermore, the dismutation energy calculations for POF4-, SOF4, and ClOF3 revealed very large errors in the previously published thermodynamic data for the heats of formations of SO2F2 and SOF4 and the dismutation reaction energy of POF4-. Energy barriers and the C-4v transition states for the Berry-style pseudorotational exchange of equatorial and axial fluorines in POF4-, SOF4, PF4-, and SF4 were also calculated and can account for the observation that on the NMR time scale the exchange in PF4- and SF4 can be frozen out at about -40 degrees C, while in POF4- and SOF4 it is still rapid at -140 and -150 degrees C, respectively. C1 UNIV SO CALIF, LOKER HYDROCARBON RES INST, LOS ANGELES, CA 90089 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. MCMASTER UNIV, DEPT CHEM, HAMILTON, ON L8S 4M1, CANADA. RP HUGHES STX, PROP DIRECTORATE, PHILLIPS LAB, EDWARDS AFB, CA 93524 USA. RI Christe, Karl/O-4885-2014 OI Christe, Karl/0000-0003-0661-5519 NR 97 TC 22 Z9 22 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 30 PY 1997 VL 119 IS 17 BP 3918 EP 3928 DI 10.1021/ja963421i PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA WW938 UT WOS:A1997WW93800008 ER PT J AU Su, XC Cremer, PS Shen, YR Somorjai, GA AF Su, XC Cremer, PS Shen, YR Somorjai, GA TI High-pressure CO oxidation on Pt(111) monitored with infrared-visible sum frequency generation (SFG) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID REFLECTION-ABSORPTION-SPECTROSCOPY; SPATIOTEMPORAL SELF-ORGANIZATION; REACTION-RATE OSCILLATIONS; VIBRATIONAL-SPECTRA; CARBON-MONOXIDE; SOLID-SURFACES; NOBLE-METALS; ADSORPTION; KINETICS; PT(100) AB Catalytic CO oxidation on Pt(111) to CO2 was studied under atmospheric pressures of CO and O-2 and at various temperatures. Surface vibrational spectroscopy by sum frequency generation was used to probe the surface species, while the reaction rate and gas composition were simultaneously monitored by gas chromatography. Correlation between the turnover rates and the surface coverage of various CO species were utilized to identify the active CO species in the reaction. Ignition, above which the reaction becomes self-sustained, divides the reaction into two reactivity regimes. Below ignition, atop bonded CO appears as the major species on the surface, but the reaction rate is inversely proportional to the surface coverage of this species, indicating that it is not the active species but rather an inhibitor. The observed activation energy for the reaction in this regime suggests that desorption of atop CO is the rate-limiting step in the reaction. Above ignition, the atop CO becomes hardly detectable and the activation energy reduces to the one directly associated with the reaction energy barrier between adsorbed CO and O on Pt. In all cases, the reaction rate is linearly proportional to the surface coverage of CO adsorbed at non-registry sites or defect (or distorted) surface sites. They are therefore identified as the active CO species in this surface catalytic reaction. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 43 TC 150 Z9 151 U1 3 U2 50 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD APR 30 PY 1997 VL 119 IS 17 BP 3994 EP 4000 DI 10.1021/ja9638723 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA WW938 UT WOS:A1997WW93800017 ER PT J AU McDermott, MT Green, JBD Porter, MD AF McDermott, MT Green, JBD Porter, MD TI Scanning force microscopic exploration of the lubrication capabilities of n-alkanethiolate monolayers chemisorbed at gold Structural basis of microscopic friction and wear SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; ATOMIC-SCALE FRICTION; INFRARED-SPECTROSCOPY; MOLECULAR ASSEMBLIES; ORGANIC-SURFACES; THIOL MONOLAYERS; SHEAR PROPERTIES; ADHESION FORCES; CHAIN-LENGTH; TUNGSTEN TIP AB This paper explores the ability of n-alkanethiolates chemisorbed at Au(111) to function as boundary lubricants at microscopic length scales as probed by scanning force microscopy (SFM). Through an examination of the influence of alkyl chain length, we show that the macroscopic structure of this system, as developed from insights into the chain-packing density via infrared reflection spectroscopy, greatly influences the observed friction and wear. That is, the longer chain monolayers exhibit a markedly lower friction and a reduced propensity to wear than the shorter chain monolayers, a situation that reflects the more extensive cohesive interactions between chains. From the combined weight of these findings, we examine the frictional process within the context of an activation mechanism that involves pressure and shear activation volumes. The ability of longer chain alkanethiolate monolayers to lubricate features that arise from changes in substrate topography is also presented, and the resulting mechanistic issues are discussed. C1 IOWA STATE UNIV, AMES LAB, US DOE, MICROANALYT INSTRUMENTAT CTR, AMES, IA 50011 USA. IOWA STATE UNIV, DEPT CHEM, AMES, IA 50011 USA. NR 73 TC 137 Z9 138 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 30 PY 1997 VL 13 IS 9 BP 2504 EP 2510 DI 10.1021/la962099m PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA WW988 UT WOS:A1997WW98800016 ER PT J AU Rye, RR AF Rye, RR TI Transition temperatures for n-alkyltrichlorosilane monolayers SO LANGMUIR LA English DT Editorial Material ID SELF-ASSEMBLED MONOLAYERS; SOLID-LIQUID INTERFACE; SILICA; OCTADECYLTRICHLOROSILANE; SURFACES RP Rye, RR (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 12 TC 41 Z9 41 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 30 PY 1997 VL 13 IS 9 BP 2588 EP 2590 DI 10.1021/la960934u PG 3 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA WW988 UT WOS:A1997WW98800032 ER PT J AU Hwang, KY Song, HK Chang, C Lee, J Lee, SY Kim, KK Choe, S Sweet, RM Suh, SW AF Hwang, KY Song, HK Chang, C Lee, J Lee, SY Kim, KK Choe, S Sweet, RM Suh, SW TI Crystal structure of thermostable alpha-amylase from Bacillus licheniformis refined at 1.7 angstrom resolution SO MOLECULES AND CELLS LA English DT Article ID X-RAY-DIFFRACTION; MOLECULAR-MODEL REFINEMENT; AMINO-ACID SEQUENCES; MACROMOLECULAR CRYSTALLOGRAPHY; WEISSENBERG CAMERA; ASPERGILLUS; CALCIUM; CRYSTALLIZATION; PROTEINS; DETECTOR AB alpha-Amylases (alpha-1,4-glucan-4-glucanohydrolase, E.C.3.2.1.1) catalyze the cleavage of alpha-1, 4-glucosidic linkages of starch components, glycogen, and various oligosaccharides. Thermostable alpha-amylases from Bacillus species are of great industrial importance in the production of corn syrup or dextrose. Thermostable alpha-amylase from Bacillus licheniformis, a monomeric enzyme with molecular mass of 55,200 Da (483 amino acid residues), shows a remarkable heat stability. This enzyme provides an attractive model for investigating the structural basis for thermostability of proteins. The three-dimensional structure of thermostable alpha-amylase from Bacillus licheniformis has been determined by the multiple isomorphous replacement method of X-ray crystallography. The structure has been refined to a crystallographic R-factor of 19.9% for 58,601 independent reflections with F-o>2 sigma Fo between 8.0 and 1.7 Angstrom resolution, with root mean square deviations of 0.013 Angstrom from ideal bond lengths and 1.72 degrees from ideal bond angles. The final model consists of 469 amino acid residues and 294 water molecules, Missing from the model are the N- and C-termini and the segment between Trp182 and Asn192. Like other alpha-amylases, the polypeptide chain folds into three distinct domains. The first domain (domain A), consisting of 291 residues (from residue 3 to 103 and 207 to 396), forms a (beta/alpha)(s)-barrel structure. The second domain (domain B), consisting of residues 104 to 206, is inserted between the third beta-strand and the third alpha-helix of domain A. The third C-terminal domain (domain C), consisting of residues 397 to 482, folds into an eight-stranded antiparallel beta-barrel. Neither calcium ion nor chloride ion is located near the active site. This study reveals the architecture of the thermostable alpha-amylase from Bacillus licheniformis. By homology with other alpha-amylases, important active site residues can be identified as Asp231, Glu261, and Asp328, which are all located at the C-terminal end of the central (beta/alpha)(s)-barrel. Since many of the stabilizing and destabilizing mutations obtained so far fall in domain B or at its border, this region of the enzyme appears to be important for thermostability. The factors responsible for the remarkable thermostability of this enzyme may be increased ionic interactions, reduced surface area, and increased packing interactions in the interior. C1 SEOUL NATL UNIV, DEPT CHEM, SEOUL 151742, SOUTH KOREA. SEOUL NATL UNIV, CTR MOL CATALYSIS, SEOUL 151742, SOUTH KOREA. SALK INST BIOL STUDIES, STRUCT BIOL LAB, LA JOLLA, CA 92037 USA. BROOKHAVEN NATL LAB, DEPT BIOL, UPTON, NY 11973 USA. RI Suh, Se Won/H-8306-2013; Song, Hyun Kyu/D-6763-2016 OI Suh, Se Won/0000-0002-1768-4635; Song, Hyun Kyu/0000-0001-5684-4059 NR 38 TC 44 Z9 47 U1 3 U2 12 PU KOREAN SOC MOLECULAR & CELLULAR BIOLOGY PI SEOUL PA 635-4, YUCKSAM-DONG, GANGNAM-GU, SEOUL 135-703, SOUTH KOREA SN 1016-8478 J9 MOL CELLS JI Mol. Cells PD APR 30 PY 1997 VL 7 IS 2 BP 251 EP 258 PG 8 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA WX199 UT WOS:A1997WX19900017 PM 9163741 ER PT J AU Whelton, BD Peterson, DP Moretti, ES Dare, H Bhattacharyya, MH AF Whelton, BD Peterson, DP Moretti, ES Dare, H Bhattacharyya, MH TI Skeletal changes in multiparous, nulliparous and ovariectomized mice fed either a nutrient-sufficient or -deficient diet containing cadmium SO TOXICOLOGY LA English DT Article DE cadmium; bone loss; pregnancy; lactation; ovariectomy; nutrient-deficient diet; Itai-Itai disease ID CD-109 METABOLISM; ORGAN RETENTION; GASTROINTESTINAL ABSORPTION; SUCCESSIVE ROUNDS; LACTATION; GESTATION; BONE; RATS; KIDNEY; EXPOSURE AB As a simulation of the etiological factors known for Itai-Itai disease, a syndrome characterized by osteomalacia and renal dysfunction in its Japanese victims, female mice were subjected to the individual and combined stresses of dietary cadmium, nutrient-deficient diet, multiparity and ovariectomy; the calcium-depleting effect of each factor was evaluated by determining Ca levels in femur and lumbar vertebrae. At age 68 days, female mice were given nutrient-sufficient (+) or -deficient (-), purified diets containing either 0.25 (environmental), 5, or 50 ppm Cd as CdCl2; the nutritional composition of (-) diet simulated that of food consumed by Japanese victims of Itai-Itai disease. At age 70 days, half of the females began a breeding regimen of six consecutive, 42-day rounds of pregnancy/lactation (PL mice); the remainder were maintained as virgin, non-pregnant controls (NP mice). Limited numbers of PL and NP mice were sacrificed at the end of each reproductive round. PL(+) mice taken at the end of round (R)-6 had successively borne litters in all six rounds, while PL(-) counterparts had nonsuccessively borne only three. At the conclusion of the 252-day reproductive period, remaining females entered the 392-day, post-reproductive phase of the experiment. At age 546 days (mid-R-12), PL females having successfully borne at least three litters were ovariectomized (OV) to mimic human menopause; at the same time, NP females were either ovariectomized or sham-operated (SO). After surgery, all females were maintained to age 714 days (mid-R-16), then sacrificed. During the post-reproductive period, food consumption by females of the same reproductive status was unaffected by elevated levels of Cd or nutrient-deficiencies in diet. However by R-16, Cd at 50 vs. 0.25 ppm had reduced body mass by 11% in both NP and PLOV females, femur and lumbar vertebral calcium content (TCa) by 20 and 25% in the respective groups, and femur and vertebral calcium/dry weight ratios (Ca/DW) by 12 and 11%. Alternative R-16 comparisons indicated that (-) diet also diminished skeletal Ca, but that the additional factors of (prior) multiparity and ovariectomy generated only small and non-significant effects. Comparison of skeletal status between the ends of the reproductive and post-reproductive periods indicated that (1) individual NP groups, regardless of Cd exposure, generally sustained small decreases in TCa and CaDW over time (consistent with aging), but PL groups without exception secured significant gains (consistent with cessation of multiparous activity), (2) skeletal integrity of PL groups was significantly more compromised by the combination of Itai etiological factors at the end of R-6 than R-16, and (3) among those factors, the most demineralizing over lifetime were chronic exposure to Cd followed by ingestion of (-) diet. Despite these findings, skeletal degeneration characteristic of the Itai-Itai syndrome was ultimately not duplicated in this mouse model suggesting that the full-blown disease required primary and profound skeletal demineralization secondarily supported and enhanced by renal dysfunction. (C) 1997 Elsevier Science Ireland Ltd. C1 ALBION COLL,ALBION,MI 49224. ARGONNE NATL LAB,CTR MECHAN BIOL & BIOTECHNOL,ARGONNE,IL 60439. RP Whelton, BD (reprint author), EASTERN WASHINGTON UNIV,DEPT CHEM & BIOCHEM,MS 74,526 5TH ST,CHENEY,WA 99004, USA. NR 38 TC 13 Z9 13 U1 2 U2 4 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0300-483X J9 TOXICOLOGY JI Toxicology PD APR 30 PY 1997 VL 119 IS 2 BP 103 EP 121 DI 10.1016/S0300-483X(96)03614-1 PG 19 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA WT475 UT WOS:A1997WT47500001 PM 9128184 ER PT J AU Whelton, BD Peterson, DP Moretti, ES Mauser, RW Bhattacharyya, MH AF Whelton, BD Peterson, DP Moretti, ES Mauser, RW Bhattacharyya, MH TI Kidney changes in multiparous, nulliparous and ovariectomized mice fed either a nutrient-sufficient or -deficient diet containing cadmium SO TOXICOLOGY LA English DT Article DE cadmium; kidney; pregnancy; lactation; ovariectomy; Itai-Itai disease ID SKELETAL LESIONS; RATS; BONE; METALLOTHIONEIN; NEPHROTOXICITY; INTOXICATION; TOXICITY; CALCIUM; PROTEIN; BINDING AB As a simulation of the etiological factors known for Itai-Itai disease, a syndrome characterized by renal dysfunction and osteomalacia in its Japanese victims, female mice were subjected to the individual and combined stresses of dietary Cd, nutrient-deficient diet, multiparity and ovariectomy. Renal function as affected by the etiological factors was periodically evaluated by determination of protein, amino acid, glucose and Cd concentrations in urine; periodic changes in skeletal Ca status were assessed relative to current renal function. Renal metabolism of Cd, Zn and Cu was also examined. At age 68 days, female mice were given nutrient-sufficient (+) or -deficient (-), purified diets containing either 0.25 (environmental), 5, or 50 ppm Cd as CdCl2; the nutritional composition of (-)diet simulated that of food consumed by Japanese victims of Itai-Itai disease. At age 70 days, half of the females began a breeding regimen of six consecutive, 42-day rounds of pregnancy/lactation (PL mice); the remainder were maintained as virgin, non-pregnant controls (NP mice). Limited numbers of PL and NP mice were sacrificed at the end of each reproductive round. PL(+) mice taken in a given round had successively borne litters in that round and all preceding ones. PL(-) females taken at the end of round (R)-1, -2 and -3 had successively borne litters through there rounds; those taken at the end of R-5 or R-6 had nonsuccessively borne litters in four of five or three of six rounds, respectively. At the conclusion of the 252-day reproductive period, remaining females entered the 392-day, post-reproductive phase of the experiment. At age 546 days (mid-R-12), PL Females having successfully borne at least three litters were ovariectomized (OV) to mimic human menopause; at the same time, NP females were either ovariectomized or sham-operated (SO). After surgery, all females were maintained to age 714 days (mid-R-16), then sacrificed. Spot urine samples were taken from individual mice at the end of most reproductive rounds (R-2 --> 6), prior to surgery (mid-R-10), and prior to final sacrifice (late-R-15); samples were also collected via metabolism cages at the ned of R-10. Food consumption, monitored on a weekly basis over the first nine rounds, was generally not significantly affected by dietary Cd level of nutrient deficiencies in females of the same reproductive status; consumption was increased about 2.5-fold in PL versus NP groups during the reproductive period and about 1.4-fold during the post-reproductive period. At each of the three dietary Cd levels and after all reproductive rounds, mean renal Cd concentrations were 1.2- to 5.6-fold higher in PL than NP mice. After six reproductive rounds, renal Cd concentrations in PL(+) and (-) groups exposed to 50 ppm Cd had reached 155 and 179 mu g Cd/g kidney, respectively. Although these levels fell within a concentration range (145-200 mu g Cd/g) where cadmium-induced renal dysfunction could be anticipated, no significant. Cd-dependent changes in mean urinary amino acid or protein concentrations were found. Moreover, among the same population, a 12% incidence of elevated urinary Cd (greater than or equal to 250 ng/ml) was noted, however none of the affected individuals exhibited depressed total calcium content (TCa) or calcium:dry weight ratios (Ca:DW) for femur. Such results suggested that the Cd-induced, skeletal demineralization observed in mice during the reproductive period (Bhattacharyya et al., Toxicology 1988a; 50: 193-204; Whelton et al., Toxicology 1994; 91: 235-251) likely occurred in the general absence of cadmium-induced renal dysfunction. By the end of the post-reproductive period, the incidence of elevated urinary Cd increased to 26% among ovariectomized females; of these, 89% with urinary Cd greater than or equal to 345 ng/ml exhibited decreases in TCa and/or Ca:DW values for femur or lumbar vertebrae that exceeded one S.D. of their group mean. Such results suggested that skeletal demineralization observed at this time (Whelton et al., Toxicology 1997a; 119: 103-121) likely occurred, for at least a portion of the population, in the presence of an ovariectomy-enhanced, cadmium-induced nephrotoxicity. During the reproductive period, small increases in Zn and Cu concentrations (ca. 1.8- and 1.5-fold, respectively) were observed for kidneys of (-) diet mice with very large increases in renal Cd concentrations (ca. 7700-fold) analogous to results previously found for (+) diet mice (Bhattacharyya et al., Toxicology 1988b; 50: 205-215). A threshold Cd concentration below which the concentration of Zn was relatively constant and independent of Cd concentration was identified (13.6 mu g Cd/g kidney); no similar threshold could be observed for Cu. At the end of six rounds, less Zn was found in the kidneys of PL(-) mice exposed to Cd at the 50 than 5 ppm level, however more Cu was found in the kidneys of both NP and PL(-) mice. (C) 1997 Elsevier Science Ireland Ltd. C1 ARGONNE NATL LAB,CTR MECHAN BIOL & BIOTECHNOL,ARGONNE,IL 60439. RP Whelton, BD (reprint author), EASTERN WASHINGTON UNIV,DEPT CHEM & BIOCHEM,MS 74,526 5TH ST,CHENEY,WA 99004, USA. NR 29 TC 7 Z9 7 U1 0 U2 3 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0300-483X J9 TOXICOLOGY JI Toxicology PD APR 30 PY 1997 VL 119 IS 2 BP 123 EP 140 DI 10.1016/S0300-483X(96)03613-X PG 18 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA WT475 UT WOS:A1997WT47500002 PM 9128185 ER PT J AU Whelton, BD Peterson, DP Moretti, ES Mauser, RW Bhattacharyya, MH AF Whelton, BD Peterson, DP Moretti, ES Mauser, RW Bhattacharyya, MH TI Hepatic levels of cadmium, zinc and copper in multiparous, nulliparous and ovariectomized mice fed either a nutrient-sufficient or -deficient diet containing cadmium SO TOXICOLOGY LA English DT Article DE cadmium; liver; pregnancy; lactation; ovariectomy; Itai-Itai disease; zinc; copper ID INDUCED NEPHROPATHY; SKELETAL LESIONS; RATS; METALLOTHIONEIN; BONE; NEPHROTOXICITY; KIDNEY; INTOXICATION AB As a simulation of etiological factors known for Itai-Itai disease, female mice were subjected to the individual and combined stresses of dietary cadmium, nutrient-deficient diet, multiparity and ovariectomy. From age 68 days, female mice were maintained on either nutrient-sufficient (+) or -deficient (-), purified diets containing either 0.25 (environmental), 5, or 50 ppm Cd as CdCl2; the nutritional composition of (-) diet simulated that of food consumed by Japanese women who contracted Itai-Itai disease. At age 70 days, half of the mice began a breeding regimen of six consecutive, 42-day rounds of pregnancy/lactation (PL mice); the remainder were maintained as virgin, non-pregnant controls (NP mice). Limited numbers of PL and NP mice were sacrificed at the end of each reproductive round. PL(+) mice taken in a given round had successively borne litters in that round and all preceding ones. PL(-) females taken at the end of round (R)-1, -2 and -3 had successively borne litters through those rounds; those taken at the end of R-5 or -6 had nonsuccessively borne litters in four of five or three of six rounds, respectively. At the end of the 252-day reproductive period, remaining females entered the 392-day, post-reproductive phase of the experiment. At age 546 days (mid-R-12), PL females having successfully borne at least three litters were ovariectomized (OV) to mimic human menopause, while NP females were either ovariectomized or sham-operated (SO). After surgery, all females were maintained to age 714 days (mid-R-16), then sacrificed. Food consumption, monitored on a weekly basis over the first nine rounds, was in general not significantly affected by dietary Cd level or nutrient deficiencies for females of the same reproductive status; consumption was increased about 2.5-fold in PL versus NP groups during the reproductive period and about 1.4-fold during the post-reproductive period. Over the reproductive period, small increases in liver concentrations of Zn and Cu were observed (cal 3.1- and 2.5-fold, respectively) with far larger increases for Cd (ca. 22200-fold). Threshold hepatic Cd concentrations below which the concentrations of Zn and Cu were relatively constant and independent of Cd concentration were identified; they were 2.7 mu g Cd/g liver for Zn and 3.3 mu g Cd/g liver for Cu for females consuming (+) diet, and 4.9 mu g Cd/g liver for Zn and 4.5 mu g Cd/g liver for Cu for females consuming (-) diet. Regardless of Cd exposure level, round-by-round hepatic concentrations of Cd were generally 2- to 6-fold higher in PL than NP mice, while Zn or Cu levels were generally only 1.1- to 2.5-fold higher. For each reproductive round, hepatic concentrations of Cd in NP females were consistently about 10-fold greater in mice exposed to 50 than 5 ppm dietary Cd; corresponding Zn levels were essentially equivalent. For PL females, Cd levels were about 7-fold greater in 50 than 5 ppm Cd-exposed groups, however Zn concentrations were about 45% decreased. The pattern of Cd, Zn and Cu sequestration established during the reproductive period clearly differed from that of the post-reproductive period. Between R-6 and -16, hepatic concentrations of Cd, Zn and Cu appreciably decreased (14-69%) in 5 ppm Cd-exposed NPOV and PLOV females regardless of diet-type consumed. At the 50 ppm Cd level, Cd and Zn concencentrations dramatically rose with increases in Cd (37-129%) exceeding those of Zn (12-21%). (C) 1997 Elsevier Science Ireland Ltd. C1 ARGONNE NATL LAB,CTR MECHAN BIOL & BIOTECHNOL,ARGONNE,IL 60439. RP Whelton, BD (reprint author), EASTERN WASHINGTON UNIV,DEPT CHEM & BIOCHEM,MS 74,526 5TH ST,CHENEY,WA 99004, USA. NR 27 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0300-483X J9 TOXICOLOGY JI Toxicology PD APR 30 PY 1997 VL 119 IS 2 BP 141 EP 153 DI 10.1016/S0300-483X(96)03612-8 PG 13 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA WT475 UT WOS:A1997WT47500003 PM 9128186 ER PT J AU Cary, RB Peterson, SR Wang, JT Bear, DG Bradbury, EM Chen, DJ AF Cary, RB Peterson, SR Wang, JT Bear, DG Bradbury, EM Chen, DJ TI DNA looping by Ku and the DNA-dependent protein kinase SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE DNA repair; atomic force microscopy; electron microscopy; double-strand break ID STRAND-BREAK-REPAIR; RNA POLYMERASE-II; V(D)J RECOMBINATION; BINDING-FACTOR; NONHOMOLOGOUS RECOMBINATION; MAMMALIAN-CELLS; TRANSCRIPTIONAL ACTIVATION; HOMOLOGOUS RECOMBINATION; CATALYTIC SUBUNIT; AUTOANTIGEN-KU AB The DNA-dependent protein kinase (DNA-PK) is required for DNA double-strand break (DSB) repair and immunoglobulin gene rearrangement and may play a role in the regulation of transcription, The DNA-PK holoenzyme is composed of three polypeptide subunits: the DNA binding Ku70/86 heterodimer and an approximate to 460-kDa catalytic subunit (DNA-PKcs), DNA-PK has been hypothesized to assemble at DNA DSBs and play structural as well as signal transduction roles in DSB repair. Recent advances in atomic force microscopy (AFM) have resulted in a technology capable of producing high resolution images of native protein and protein nucleic acid complexes without staining or metal coating. The AFM provides a rapid and direct means of probing the protein-nucleic acid interactions responsible for DNA repair and genetic regulation, Here we have employed AFM as well as electron microscopy to visualize Ku and DNA-PK in association with DNA. A significant number of DNA molecules formed loops in the presence of Ku. DNA looping appeared to be sequence-independent and unaffected by the presence of DNA-PKcs, Gel filtration of Ku in the absence and the presence of DNA indicates that Ku does not form nonspecific aggregates. We conclude that, when bound to DNA, Ku is capable of self-association. These findings suggest that Ku binding at DNA DSBs will result in Ku self-association and a physical tethering of the broken DNA strands. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. UNIV NEW MEXICO,HLTH SCI CTR,DEPT CELL BIOL,ALBUQUERQUE,NM 87131. UNIV NEW MEXICO,HLTH SCI CTR,CTR CANC,ALBUQUERQUE,NM 87131. UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95606. FU NCI NIH HHS [CA50519, R01 CA050519, R37 CA050519] NR 63 TC 190 Z9 196 U1 2 U2 3 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 29 PY 1997 VL 94 IS 9 BP 4267 EP 4272 DI 10.1073/pnas.94.9.4267 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WX362 UT WOS:A1997WX36200008 PM 9113978 ER PT J AU Li, SP Eastman, JA Thompson, LJ AF Li, SP Eastman, JA Thompson, LJ TI Gas-condensation synthesis of nanocrystalline BaTiO3 SO APPLIED PHYSICS LETTERS LA English DT Article ID BARIUM-TITANATE CERAMICS; DIELECTRIC-PROPERTIES AB Nanocrystalline BaTiO3 has been prepared by a gas-condensation process. BaTiO3 and Ti sources are vaporized simultaneously in either a helium or an oxygen environment using an electron beam evaporation system. The stoichiometry of nanocrystalline BaTiO3 powders can be controlled precisely and reproducibly. Nanocrystalline BaTiO3 powders, with an average particle size of less than 20 nm, can be obtained by postannealing the as-evaporated powders at a temperature of 700 degrees C. These powders show good sintering behavior with a high density at a sintering temperature as low as 1250 degrees C. Differential thermal analysis indicated that nanocrystalline BaTiO3 was formed through the reaction of Ba/Ti oxidized clusters. Dielectric properties of ceramics from nanocrystalline BaTiO3 are also reported. (C) 1997 American Institute of Physics. RP Li, SP (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Eastman, Jeffrey/E-4380-2011 NR 10 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 28 PY 1997 VL 70 IS 17 BP 2244 EP 2246 DI 10.1063/1.118828 PG 3 WC Physics, Applied SC Physics GA WW272 UT WOS:A1997WW27200011 ER PT J AU Wolk, JA Yu, KM BourretCourchesne, ED Johnson, E AF Wolk, JA Yu, KM BourretCourchesne, ED Johnson, E TI Synthesis of GaN nanocrystals by sequential ion implantation SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR AB We have synthesized GaN nanocrystals by sequential implantation of Ga and N ions into a sapphire substrate followed by a postimplantation anneal. The nanocrystals have been identified as the wurtzite phase alpha-GaN structure by transmission electron microscopy, We also found that the nanocrystals are aligned with the sapphire following the relationship: (0001)(sapphire)\\(0001)(GaN) and (<11(20)over bar>)(sapphire)\\(<11(20)over bar>)(GaN). The use of a sapphire substrate allows for the measurements of optical properties, and near band-edge luminescence and the yellow band are observed in photoluminescence spectroscopy. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,DIV SCI MAT,BERKELEY,CA 94720. RP Wolk, JA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV SCI MAT,MS 2-200,BERKELEY,CA 94720, USA. RI Yu, Kin Man/J-1399-2012 OI Yu, Kin Man/0000-0003-1350-9642 NR 18 TC 25 Z9 29 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 28 PY 1997 VL 70 IS 17 BP 2268 EP 2270 DI 10.1063/1.118850 PG 3 WC Physics, Applied SC Physics GA WW272 UT WOS:A1997WW27200019 ER PT J AU Loehle, C AF Loehle, C TI A hypothesis testing framework for evaluating ecosystem model performance SO ECOLOGICAL MODELLING LA English DT Article DE model testing; goodness-of-fit; sensitivity analysis; error analysis; model performance; validation ID WATER-QUALITY MODELS; ASSESSMENT METHODOLOGY; SUCCESSIONAL SYSTEMS; SENSITIVITY ANALYSIS; ERROR ANALYSIS; UNCERTAINTY; VALIDATION AB Model evaluation is argued to necessitate the use of a hypothesis testing framework instead of the use of goodness-of-fit (GOF) against time series data. A test statistic T is developed, based on model deviation from expected system behaviors. If a model does not exceed the error bounds on expected behavior, then we cannot say that it differs from the real system. Precision is measured not by degree of fit to a set of data but by the precision (width of confidence limits around) the expected system behavior. Implementation of this approach is enhanced by development of new test criteria that evaluate biological and ecological realism based on aggregate indices, failure modes, extreme condition tests, and others. Model performance is assessed by the extent to which the model falls within these expected bounds. Using this test statistic as a basis, revised approaches to sensitivity and uncertainty analysis are recommended. Factors not addressed by these techniques require structural analysis, which is based on comparisons between models with different structures. The application of the advocated approach should enhance confidence in ecosystem models applied to policy issues such as natural resource management or global change impacts. (C) 1997 Elsevier Science B.V. RP Loehle, C (reprint author), ARGONNE NATL LAB,DIV ENVIRONM RES,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 36 TC 48 Z9 62 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD APR 28 PY 1997 VL 97 IS 3 BP 153 EP 165 DI 10.1016/S0304-3800(96)01900-X PG 13 WC Ecology SC Environmental Sciences & Ecology GA XB335 UT WOS:A1997XB33500001 ER PT J AU ValerioLepiniec, M Delcroix, JD Schiffer, M Hanson, DK Sebban, P AF ValerioLepiniec, M Delcroix, JD Schiffer, M Hanson, DK Sebban, P TI A native electrostatic environment near Q(B) is not sufficient to ensure rapid proton delivery in photosynthetic reaction centers SO FEBS LETTERS LA English DT Article DE photosynthesis; reaction center; electrostatic interaction; proton transfer; electron transfer; site-specific mutagenesis ID BACTERIAL REACTION CENTERS; RHODOBACTER-SPHAEROIDES; BINDING-SITE; RHODOPSEUDOMONAS-VIRIDIS; SECONDARY QUINONE; 2ND-SITE MUTATION; PATHWAY; PROTEIN; RESOLUTION; CAPSULATUS AB Flash-induced absorption spectroscopy has been used to characterize Rhodobacter capsulatus reaction centers mutated in the secondary quinone acceptor site (Q(B)). We compared the wild-type, the L212Glu-L2l3Asp --> Ala-Ala photosynthetically incompetent double mutant (DM), and two photocompetent revertants, the DM+L217Arg --> Cys and the DM+M5Asn --> Asp strains, The electrostatic environment for O-B(-) is different in the two revertant strains, Only the L217Arg --> Cys mutation nearly restores the native electrostatic environment of Q(B)(-). However, the level of recovery of the reaction center function, measured by the rates of second electron transfer and cytochrome c turnover, is quite incomplete in both strains, This shows that a wild-type-like electrostatic environment of Q(B)(-) cannot ensure on its own, rapid and efficient proton transfer to Q(B)(-). (C) 1997 Federation of European Biochemical Societies. C1 ARGONNE NATL LAB,CTR MECH BIOL & BIOTECHNOL,ARGONNE,IL 60439. RP ValerioLepiniec, M (reprint author), CNRS,CTR GENET MOL,F-91198 GIF SUR YVETTE,FRANCE. FU NIGMS NIH HHS [GM36598] NR 31 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD APR 28 PY 1997 VL 407 IS 2 BP 159 EP 163 DI 10.1016/S0014-5793(97)00328-1 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA WX265 UT WOS:A1997WX26500007 PM 9166891 ER PT J AU Pierce, DM Bagger, JA Matchev, KT Zhang, RJ AF Pierce, DM Bagger, JA Matchev, KT Zhang, RJ TI Precision corrections in the minimal supersymmetric standard model SO NUCLEAR PHYSICS B LA English DT Review DE supersymmetry; radiative corrections; precision measurements; grand unification ID HIGGS-BOSON MASS; RENORMALIZATION-GROUP EQUATIONS; ONE-LOOP RENORMALIZATION; SOFTLY BROKEN SUPERSYMMETRY; QUANTUM-FIELD THEORY; ELECTROWEAK SYMMETRY-BREAKING; LINEAR E(+)E(-) COLLIDERS; GRAND UNIFIED THEORIES; RADIATIVE-CORRECTIONS; DIMENSIONAL REDUCTION AB In this paper we compute one-loop corrections to masses and couplings in the minimal super-symmetric standard model. We present explicit formulae for the complete corrections and a set of compact approximations which hold over the unified parameter space associated with radiative electroweak symmetry breaking. We illustrate the importance of the corrections and the accuracy of our approximations by scanning over the parameter space. We calculate the supersymmetric one-loop corrections to the W-boson mass, the effective weak mixing angle, and the quark and lepton masses, and discuss implications for gauge and Yukawa coupling unification. We also compute the one-loop corrections to the entire superpartner and Higgs-boson mass spectrum. We find significant corrections over much of the parameter space, and illustrate that our approximations are good to O(1%) for many of the superparticle masses. (C) 1997 Elsevier Science B.V. C1 JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. RP Pierce, DM (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 124 TC 747 Z9 747 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD APR 28 PY 1997 VL 491 IS 1-2 BP 3 EP 67 DI 10.1016/S0550-3213(96)00683-9 PG 65 WC Physics, Particles & Fields SC Physics GA WV798 UT WOS:A1997WV79800001 ER PT J AU Albuquerque, IF Bondar, NF Carrigan, R Chen, D Cooper, PS Dai, LS Denisov, AS Dobrovolsky, AV Dubbs, T Endler, AMF Escobar, CO Foucher, M Golovtsov, VL Gottschalk, H Gouffon, P Grachev, VT Khanzadeev, AV Kubantsev, MA Kuropatkin, NP Lach, J Langland, J Lang, PF Li, CZ Li, YS Luksys, M Mahon, JRP McCliment, E Morelos, A Newsom, C Maia, MCP Samsonov, VM Schegelsky, VA Shi, HZ Smith, VJ Tang, FK Terentyev, NK Timm, S Tkatch, II Uvarov, LN Vorobyov, AA Jie, Y Zhao, WH Zheng, SC Zhong, YY AF Albuquerque, IF Bondar, NF Carrigan, R Chen, D Cooper, PS Dai, LS Denisov, AS Dobrovolsky, AV Dubbs, T Endler, AMF Escobar, CO Foucher, M Golovtsov, VL Gottschalk, H Gouffon, P Grachev, VT Khanzadeev, AV Kubantsev, MA Kuropatkin, NP Lach, J Langland, J Lang, PF Li, CZ Li, YS Luksys, M Mahon, JRP McCliment, E Morelos, A Newsom, C Maia, MCP Samsonov, VM Schegelsky, VA Shi, HZ Smith, VJ Tang, FK Terentyev, NK Timm, S Tkatch, II Uvarov, LN Vorobyov, AA Jie, Y Zhao, WH Zheng, SC Zhong, YY TI Search for light supersymmetric baryons SO PHYSICAL REVIEW LETTERS LA English DT Article ID DECAY AB We have searched for the production and decay of light supersymmetric baryons produced in 800 GeV/c proton copper interactions in a charged hyperon beam experiment. We observe no evidence for the decays R+() --> S-0()pi(+) and X-() --> S-0()pi(-) in the parent mass and lifetime ranges of 1700-2500 MeV/c(2) and 50-500 ps. Production upper limits for R+ at x(F) = 0.47, P-t = 1.4 GeV/c(2) and X- at x(F) = 0.48, P-t = 0.65 GeV/c(2) of less than 10(-3) of all charged secondary particles produced are obtained for all but the highest masses and shortest lifetimes predicted. C1 FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. INST HIGH ENERGY PHYS,BEIJING 100039,PEOPLES R CHINA. ST PETERSBURG NUCL PHYS INST,GATCHINA,RUSSIA. INST THEORET & EXPT PHYS,MOSCOW 117259,RUSSIA. UNIV IOWA,IOWA CITY,IA 52242. UNIV SAO PAULO,SAO PAULO,BRAZIL. YALE UNIV,JW GIBBS LAB,NEW HAVEN,CT 06511. CTR BRASILEIRO PESQUISAS FIS,RIO JANEIRO,BRAZIL. CNPQ,CONSELHO NACL PESQUISAS,RIO JANEIRO,BRAZIL. SUNY ALBANY,ALBANY,NY 12222. UNIV BRISTOL,HH WILLS PHYS LAB,BRISTOL BS8 1TL,AVON,ENGLAND. CARNEGIE MELLON UNIV,PITTSBURGH,PA 15213. UNIV FED PARAIBA,BR-58059900 JOAO PESSOA,PARAIBA,BRAZIL. RI Albuquerque, Ivone/H-4645-2012; Gouffon, Philippe/I-4549-2012 OI Albuquerque, Ivone/0000-0001-7328-0136; Gouffon, Philippe/0000-0001-7511-4115 NR 10 TC 33 Z9 33 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3252 EP 3256 DI 10.1103/PhysRevLett.78.3252 PG 5 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900007 ER PT J AU Atwood, D Dunietz, I Soni, A AF Atwood, D Dunietz, I Soni, A TI Enhanced CP violation with B->KD0((D)over-bar(0)) modes and extraction of the Cabibbo-Kobayashi-Maskawa angle gamma SO PHYSICAL REVIEW LETTERS LA English DT Article AB The Gronau-London-Wyler method extracts the Cabibbo-Kobayashi-Maskawa angle gamma by measuring B+/- decay rates involving D-0/<(D)over bar(0)> mesons. CP violation can be greatly enhanced for decays to final states common to both D-0 and <(D)over bar(0)> that are not CP eigenstates. Large asymmetries are possible for final states f such that D-0 --> f is doubly Cabibbo suppressed while <(D)over bar(0)> --> f is Cabibbo allowed. The measurement of interference effects in such modes allows the clean extraction of gamma. C1 FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Atwood, D (reprint author), THOMAS JEFFERSON NATL ACCELERATOR FACIL,NEWPORT NEWS,VA 23606, USA. NR 19 TC 389 Z9 391 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3257 EP 3260 DI 10.1103/PhysRevLett.78.3257 PG 4 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900008 ER PT J AU Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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 Efimov, A Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Brower, WS Masek, G Paar, HP Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BJ 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 McLean, KW Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoller, MM Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M AF Bishai, M Fast, J Gerndt, E Hinson, JW Menon, N Miller, DH Shibata, EI Shipsey, IPJ Yurko, M Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF 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 Efimov, A Frasconi, F Gao, M Goldberg, M He, D Kopp, S Moneti, GC Mountain, R Mukhin, Y Schuh, S Skwarnicki, T Stone, S Viehhauser, G Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Godang, R Kinoshita, K Lai, IC Pomianowski, P Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Bliss, DW Brower, WS Masek, G Paar, HP Sharma, V Gronberg, J Kutschke, R Lange, DJ Menary, S Morrison, RJ Nelson, HN Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Witherell, MS Balest, R Behrens, BH Cho, K Ford, WT Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Ecklund, KM Ehrlich, R Elia, R Foland, AD Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Kandaswamy, J Katayama, N Kim, PC Kreinick, DL Lee, T Liu, Y Ludwig, GS Masui, J Mevissen, J Mistry, NB Ng, CR Nordberg, E Ogg, M Patterson, JR Peterson, D Riley, D Soffer, A Ward, C Athanas, M Avery, P Jones, CD Lohner, M Prescott, C Yang, S Yelton, J Zheng, J Brandenburg, G Briere, RA Gao, YS Kim, DYJ Wilson, R Yamamoto, H Browder, TE Li, F Li, Y Rodriguez, JL Bergfeld, T Eisenstein, BJ 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 McLean, KW Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Coppage, D Darling, C Davis, R Hancock, N Kotov, S Kravchenko, I Kwak, N Anderson, S Kubota, Y Lattery, M ONeill, JJ Patton, S Poling, R Riehle, T Savinov, V Smith, A Alam, MS Athar, SB Ling, Z Mahmood, AH Severini, H Timm, S Wappler, F Anastassov, A Blinov, S Duboscq, JE Fisher, KD Fujino, D Fulton, R Gan, KK Hart, T Honscheid, K Kagan, H Kass, R Lee, J Spencer, MB Sung, M Undrus, A Wanke, R Wolf, A Zoller, MM Nemati, B Richichi, SJ Ross, WR Skubic, P Wood, M TI Analysis of D+->K-S((0))K+ and D+->K-S((0))pi(+) SO PHYSICAL REVIEW LETTERS LA English DT Article ID BRANCHING FRACTION; DECAYS; MESONS; D+ AB Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we present new measurements of the branching fractions for D+ --> KSK+ and D+ --> K-S pi(+). These results are combined with other CLEO measurements to extract the ratios of isospin amplitudes and phase shifts for D --> KK and D --> K pi. C1 UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. WAYNE STATE UNIV,DETROIT,MI 48202. CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,BOULDER,CO 80309. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. INST PARTICLE PHYS,MONTREAL,PQ H3A 2T8,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. UNIV TEXAS,AUSTIN,TX 78712. BINP,RU-630090 NOVOSIBIRSK,RUSSIA. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Bishai, M (reprint author), PURDUE UNIV,W LAFAYETTE,IN 47907, USA. RI Schaffner, Stephen/D-1189-2011; Briere, Roy/N-7819-2014; Frasconi, Franco/K-1068-2016 OI Briere, Roy/0000-0001-5229-1039; Frasconi, Franco/0000-0003-4204-6587 NR 18 TC 20 Z9 20 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3261 EP 3265 DI 10.1103/PhysRevLett.78.3261 PG 5 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900009 ER PT J AU Buryak, AV Kivshar, YS AF Buryak, AV Kivshar, YS TI Multistability of three-wave parametric self-trapping SO PHYSICAL REVIEW LETTERS LA English DT Article ID SOLITON PULSE-PROPAGATION; BISTABLE SOLITONS; NONLINEARITIES; LIGHT AB We reveal that three-wave parametric mixing in a diffractive quadratic (or chi((2))) medium can lead to multistability of self-guided beams. Switching between different stable states of these multivalued spatial solitary waves is also demonstrated. C1 AUSTRALIAN DEF FORCE ACAD,SCH MATH & STAT,CANBERRA,ACT 2600,AUSTRALIA. LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP Buryak, AV (reprint author), AUSTRALIAN NATL UNIV,RES SCH PHYS SCI & ENGN,CTR OPT SCI,CANBERRA,ACT 0200,AUSTRALIA. NR 17 TC 50 Z9 50 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3286 EP 3289 DI 10.1103/PhysRevLett.78.3286 PG 4 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900015 ER PT J AU Glendinning, SG Dixit, SN Hammel, BA Kalantar, DH Key, MH Kilkenny, JD Knauer, JP Pennington, DM Remington, BA Wallace, RJ Weber, SV AF Glendinning, SG Dixit, SN Hammel, BA Kalantar, DH Key, MH Kilkenny, JD Knauer, JP Pennington, DM Remington, BA Wallace, RJ Weber, SV TI Measurement of a dispersion curve for linear-regime Rayleigh-Taylor growth rates in laser-driven planar targets SO PHYSICAL REVIEW LETTERS LA English DT Article ID INSTABILITY; FUSION; PLASMAS; NOVA AB A dispersion curve for Rayleigh-Taylor growth rates in the linear regime has been measured in planar CH2 laser-driven foils. The foils were ablatively accelerated with a single, smoothed, frequency-doubled beam of the Nova laser at 7 x 10(13) W/cm(2) (giving an acceleration of 60 mu m/ns(2)). Measured growth rates were about 50% of the classical values. Growth rates simulated with the computer code LASNEX were similar to 18% higher than measured values. C1 RUTHERFORD APPLETON LAB,DIDCOT,OXON,ENGLAND. UNIV OXFORD,OXFORD,ENGLAND. UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY 14623. RP Glendinning, SG (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 29 TC 84 Z9 85 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3318 EP 3321 DI 10.1103/PhysRevLett.78.3318 PG 4 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900023 ER PT J AU Tanaka, S Bartelt, NC Umbach, CC Tromp, RM Blakely, JM AF Tanaka, S Bartelt, NC Umbach, CC Tromp, RM Blakely, JM TI Step permeability and the relaxation of biperiodic gratings on Si(001) SO PHYSICAL REVIEW LETTERS LA English DT Article AB We have used low energy electron microscopy to study the time dependence of atomic height islands and holes at the extrema of a fabricated biperiodic grating on Si(001), From the pairwise disappearance of these islands and holes as the grating thermally smooths we conclude that steps on Si(001) are remarkably permeable, i.e., adatoms can cross steps without becoming incorporated into them. Comparison of the time dependence of the island areas with model calculations shows that the adatom incorporation probability is actually much smaller than the crossing probability. C1 SANDIA NATL LABS,LIVERMORE,CA 94551. IBM CORP,DIV RES,TJ WATSON RES CTR,YORKTOWN HTS,NY 10598. RP Tanaka, S (reprint author), CORNELL UNIV,DEPT MAT SCI & ENGN,ITHACA,NY 14853, USA. NR 12 TC 96 Z9 98 U1 0 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3342 EP 3345 DI 10.1103/PhysRevLett.78.3342 PG 4 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900029 ER PT J AU Pang, Y Kahana, DE Kahana, SH AF Pang, Y Kahana, DE Kahana, SH TI (p)over-bar annihilation in Au+Au at 11 GeV/c SO PHYSICAL REVIEW LETTERS LA English DT Editorial Material ID ANTIPROTON PRODUCTION; COLLISIONS C1 SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11791. COLUMBIA UNIV,DEPT PHYS,NEW YORK,NY 10027. RP Pang, Y (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 4 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 28 PY 1997 VL 78 IS 17 BP 3418 EP 3418 DI 10.1103/PhysRevLett.78.3418 PG 1 WC Physics, Multidisciplinary SC Physics GA WW399 UT WOS:A1997WW39900048 ER PT J AU Katul, G Oren, R Ellsworth, D Hsieh, CI Phillips, N Lewin, K AF Katul, G Oren, R Ellsworth, D Hsieh, CI Phillips, N Lewin, K TI A Lagrangian dispersion model for predicting CO2 sources, sinks, and fluxes in a uniform loblolly pine (Pinus taeda L) stand SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RANDOM-WALK MODEL; ATMOSPHERIC SURFACE-LAYER; CONVECTIVE BOUNDARY-LAYER; TURBULENT VELOCITY SCALE; NEAR-FIELD DISPERSION; PARTICLE TRAJECTORIES; INHOMOGENEOUS TURBULENCE; NUMERICAL-SIMULATION; SOURCE DISTRIBUTIONS; PLANT CANOPIES AB A canopy Lagrangian turbulent scalar transport model for predicting scalar fluxes, sources, and sinks within a forested canopy was tested using CO2 concentration and flux measurements. The model formulation is based on the localized near-field theory (LNF) proposed by Raupach [1989a, b]. Using the measured mean CO2 concentration profile, the vertical velocity variance profile, and the Lagrangian integral timescale profile within and above a forested canopy, the proposed model predicted the CO2 flux and source (or sink) profiles, The model testing was carried out using eddy correlation measurements at 9 m in a uniform 13 m tall Pinus taeda L. (loblolly pine) stand at the Blackwood division of the Duke Forest near Durham, North Carolina. The tree height and spacing are relatively uniform throughout. The measured vertical profile leaf area index (LAI) was characterized by three peaks, with a maximum LAI occurring at 6.5 m, in qualitative agreement with the LNF source-sink predicted profile. The LNF CO2 flux predictions were in better agreement with eddy correlation measurements (coefficient of determination r(2) = 0.58; and standard error of estimate equal to 0.16 mg kg(-1) m s(-1)) than K theory. The model reproduced the mean diurnal CO2 flux, suggesting better performance over longer averaging time periods. Two key simplifications to the LNF formulation were considered, namely, the near-Gaussian approximation to the vertical velocity and the absence of longitudinal advection. It was found that both of these assumptions were violated throughout the day, but the resulting CO2 flux error at 9 m was not strongly related to these approximations. In contrast to the forward LNF approach utilized by other studies, this investigation demonstrated that the inverse LNF approach is sensitive to near-field corrections. C1 BROOKHAVEN NATL LAB, DEPT APPL SCI, UPTON, NY 11973 USA. DUKE UNIV, CTR HYDROL SCI, DURHAM, NC USA. RP DUKE UNIV, SCH ENVIRONM, DURHAM, NC 27708 USA. RI Katul, Gabriel/A-7210-2008 OI Katul, Gabriel/0000-0001-9768-3693 NR 58 TC 74 Z9 75 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 1997 VL 102 IS D8 BP 9309 EP 9321 DI 10.1029/96JD03785 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WW559 UT WOS:A1997WW55900001 ER PT J AU Kumaran, SS Su, MC Michael, JV AF Kumaran, SS Su, MC Michael, JV TI Thermal decomposition of iodobenzene using I-atom absorption SO CHEMICAL PHYSICS LETTERS LA English DT Article ID COLLISION RATE CONSTANTS; BOND-DISSOCIATION ENERGIES; SHOCK-TUBE TECHNIQUE; FALL-OFF RANGE; UNIMOLECULAR REACTIONS; LOW-PRESSURES; TEMPERATURE; PHOTOLYSIS; FLASH; BENZENE AB The I-atom atomic resonance absorption spectrometric (ARAS) technique has been used in Kr bath gas to study the thermal decomposition kinetics of iodobenzene, C6H5I, over T- and P-ranges of 1082-1416 K and 103-731 Torr, giving the first order expression, k(+/-60%) = 1.982 X 10(11) exp(-23120K/T) s(-1). Two unimolecular theoretical approaches were used to rationalize the data implying E-0 = Delta H-0(0) = (66.7 +/- 0.7) kcal mol(-1) and [Delta E](down) = (447 +/- 92) cm(-1). C1 DEPT EDUC PROGRAMS,ARGONNE,IL. BUTLER UNIV,DEPT CHEM,INDIANAPOLIS,IN 46208. RP Kumaran, SS (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Michael, Joe/E-3907-2010 NR 40 TC 19 Z9 19 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD APR 25 PY 1997 VL 269 IS 1-2 BP 99 EP 106 DI 10.1016/S0009-2614(97)00256-X PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WV113 UT WOS:A1997WV11300016 ER PT J AU Wolf, SF Wang, MS Dodd, RT Lipschutz, ME AF Wolf, SF Wang, MS Dodd, RT Lipschutz, ME TI Chemical studies of H chondrites .8. On contemporary meteoroid streams SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID PARENT BODY; METEORITES; BREAKUP; EARTH; FLUX AB Using date and time of fall and petrographic classification as criteria, many equilibrated H chondrites that fell during September and October from 1812 to the present form four significant-clusters, denoted as Cluster 2 through Cluster 5, on day-year plots. Using radiochemical neutron activation analysis, we determined 15 trace elements, U, Au, Co, Sb, Ga, Rb, Ag, Se, Cs, Te, Zn, Cd, Bi, Tl, and In (ordered by increasing putative volatility during nebular condensation), in 27 members of these four clusters. We used model-dependent and model-independent multivariate statistical techniques to compare contents of the 10 most volatile elements separately in the four clusters with those of a 33-member suite of random H chondrite falls (from 1773 to 1970). The Clusters 2 and 5 suites (that fell in September 1880-1991 and October, 1919-1984, respectively), each of which is represented by 10 H chondrite falls, are not compositionally distinguishable from the suite of random falls. However, the 17-member combined suite of Clusters 3 and 4 chondrites (that fell during September-October, 1812-1992) proves compositionally distinguishable from random falls at moderate to strong significance levels of 0.01-0.001. This 17-member suite is less readily distinguished from random falls than are the previously reported suite of Cluster 1 falls (May 1855-1895), or Antarctic H chondrites with nominal terrestrial ages >50 kyr, each of which is highly significant at <0.001 levels. All suites are genomict and exhibit a range of cosmic ray exposure ages with a plurality having 6-8 Ma ages. Inconclusive results are obtained in the cases of Clusters 2 and 5. However, three H chondrite suites (Clusters 1, 3, and 4) distinguishable from the random background by one property (time of fall) are also distinguishable by another (contents of volatile trace elements or thermal history). Temporal change of H chondrite sources sampled by Earth are indicated by these data. C1 PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. RP Wolf, SF (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 34 TC 7 Z9 7 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 1997 VL 102 IS E4 BP 9273 EP 9288 DI 10.1029/97JE00137 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WX323 UT WOS:A1997WX32300022 ER PT J AU Prange, R Maurice, S Harris, WM Rego, D Livengood, T AF Prange, R Maurice, S Harris, WM Rego, D Livengood, T TI Comparison of IUE and HST diagnostics of the Jovian Aurorae SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HUBBLE-SPACE-TELESCOPE; UV AURORA; NORTH; ULTRAVIOLET; JUPITER; PRECIPITATION; MORPHOLOGY; EMISSIONS; EVENT AB Analysis of international ultraviolet explorer (IUE) and Voyager ultraviolet spectrometer (UVS) spectra, of the Jovian auroral emission indicates that the Jovian auroral brightness is modulated in longitude (brighter near 180 degrees in the north and 20 degrees in the south) and that there is a color ratio asymmetry associated with this brightening. The purpose of this study is to investigate the origin of this apparent asymmetry. To that end, we use. a series of six typical images of the north auroral region taken in the. H-2 Lyman bands with the. faint object camera (FOG) aboard the Hubble. space telescope (HST) and which cover a full Jovian rotation. Although the images do not display any strong brightening near 180 degrees, once we have: simulated the signal IUE would,see through its aperture, we find the characteristic longitudinal modulation. We attribute most of this modulation to a combination of viewing geometry effects near the. east and west ansae of the auroral oval (already taken into account in previous studies) and of the spatial degradation of the source by the. IUE instrument function (never considered so far), and we. suggest qualitatively that these effects may also affect the color ratio asymmetry. Nevertheless, part of the asymmetry seems to be due. to an intrinsic modulation associated with a bright feature crossing the polar cap along the 160 degrees meridian (transpolar emission) and present in roost of the images. We then use a series of FOC images taken during an atypically strong auroral event, and we. show that the same effects can again account for the anomalous brightness variations observed simultaneously with IUE. C1 UNIV WISCONSIN,SPACE ASTRON LAB,MADISON,WI 53706. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 21771. LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,NIS 1,LOS ALAMOS,NM 87545. INST ASTROPHYS PARIS,PARIS,FRANCE. EUROPEAN SPACE AGCY,EUROPEAN SPACE RES & TECHNOL CTR,DEPT SPACE SCI,NL-2200 AG NOORDWIJK,NETHERLANDS. RP Prange, R (reprint author), UNIV PARIS 11,INST ASTROPHYS SPATIALE,CNRS,BAT 121,F-91405 ORSAY,FRANCE. RI Livengood, Timothy/C-8512-2012 NR 25 TC 13 Z9 13 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 1997 VL 102 IS E4 BP 9289 EP 9301 DI 10.1029/96JE03304 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA WX323 UT WOS:A1997WX32300023 ER PT J AU Ehrenfeld, D Noss, RF Meffe, GK AF Ehrenfeld, D Noss, RF Meffe, GK TI Endangered species ''hot spots'' SO SCIENCE LA English DT Letter C1 OREGON STATE UNIV,CORVALLIS,OR 97331. SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. RP Ehrenfeld, D (reprint author), RUTGERS STATE UNIV,COOK COLL,NEW BRUNSWICK,NJ 08903, USA. NR 0 TC 4 Z9 6 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 25 PY 1997 VL 276 IS 5312 BP 515 EP 516 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WV721 UT WOS:A1997WV72100008 ER PT J AU Lear, KL Hou, HQ Banas, JJ Hammons, BE Furioli, J Osinski, M AF Lear, KL Hou, HQ Banas, JJ Hammons, BE Furioli, J Osinski, M TI Vertical cavity lasers on p-doped substrates SO ELECTRONICS LETTERS LA English DT Article DE vertical cavity surface emitting lasers; semiconductor junction lasers ID RESISTANCE AB Vertical cavity surface emitting laser (VCSEL) diodes fabricated with inverted polarity, i.e. p-type bottom mirror and n-type top mirror, are reported with lower resistance and diode voltage and comparable output characteristics relative to similar conventional, non-inverted structures. C1 UNIV NEW MEXICO,CTR HIGH TECHNOL MAT,ALBUQUERQUE,NM 87131. RP Lear, KL (reprint author), SANDIA NATL LABS,PHOTON RES DEPT,MS 0603,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 9 TC 12 Z9 12 U1 1 U2 2 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD APR 24 PY 1997 VL 33 IS 9 BP 783 EP 784 DI 10.1049/el:19970492 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA WX459 UT WOS:A1997WX45900040 ER PT J AU Chang, TM Dang, LX Peterson, KA AF Chang, TM Dang, LX Peterson, KA TI Computer simulation of chloroform with a polarizable potential model SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; LIQUID CHLOROFORM; DYNAMICS SIMULATION; SURFACE-TENSION; WATER AB A series of molecular dynamics simulations were carried out to examine the thermodynamic and the structural properties of the liquid and liquid/vapor of chloroform. A polarizable potential model was used to describe the intermolecular chloroform-chloroform interactions. The computed liquid densities and the enthalpies of vaporization and their corresponding temperature dependence are in excellent agreement with experimental values. The radial distribution functions and the corresponding neutron scattering cross sections were critically evaluated against the experimental data. The agreement between both approaches was found to be quite reasonable. The equilibrium interfacial properties of the chloroform liquid/vapor were also evaluated. The computed density profile shows that the interface is not sharp at a microscopic level and has a thickness of 5.9 Angstrom at 298 K. The calculated surface tensions as a function of temperature are in good agreement with the corresponding experimental data. Accurate ab initio calculations were also carried out on the chloroform dimer, and the result for the binding energy was in good agreement with the value obtained from the molecular dynamics model. C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. WASHINGTON STATE UNIV, DEPT CHEM, RICHLAND, WA 99352 USA. NR 28 TC 72 Z9 72 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 24 PY 1997 VL 101 IS 17 BP 3413 EP 3419 DI 10.1021/jp9638550 PG 7 WC Chemistry, Physical SC Chemistry GA WV892 UT WOS:A1997WV89200015 ER PT J AU Wu, RW Tucker, JD Sorensen, KJ Thompson, LH Felton, JS AF Wu, RW Tucker, JD Sorensen, KJ Thompson, LH Felton, JS TI Differential effect of acetyltransferase expression on the genotoxicity of heterocyclic amines in CHO cells SO MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS LA English DT Article DE Chinese hamster ovary; acetyltransferase; food mutagen; 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine; 2-amino-3-methylimidazo[4,5-f]quinoline; cytogenetic testing; mutagenesis ID FOOD MUTAGEN 2-AMINO-1-METHYL-6-PHENYLIMIDAZO<4,5-B>PYRIDINE; ARYLAMINE N-ACETYLTRANSFERASES; SISTER-CHROMATID EXCHANGE; HAMSTER OVARY CELLS; METABOLIC-ACTIVATION; AROMATIC-AMINES; COOKED-FOOD; SALMONELLA-TYPHIMURIUM; REPAIR-DEFICIENT; DNA-REPAIR AB We earlier developed the Chinese hamster ovary UV5P3 cell line that expresses cytochrome P4501A2 and lacks nucleotide excision repair for studying metabolism and mutagenicity of heterocyclic amines. The Chinese hamster ovary UV5P3 cells are approximately 50-fold more sensitive to the cooked food mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) than 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), another genotoxic compound found in cooked food, with respect to cytotoxicity and mutation induction at the adenine phosphoribosyltransferase (aprt) locus. To test the hypothesis that the important missing activity in our CHO system for IQ genotoxicity was acetyltransferase, we transfected the UV5P3 cells with cDNA plasmids of either the human NAT2 N-acetyltransferase gene or a bacterial O-acetyltransferase gene. Functionally transformed clones were determined by the differential cytotoxicity assay using IQ, and confirmed by measuring the enzyme activity with isoniazid as substrate. Two clones designated 5P3NAT2 and 5P3YG (expressing human and bacterial transferases, respectively) were characterized. Both cell lines were sensitive to killing by IQ at concentrations as low as 4 ng/ml. Based on the D-37 value, the dose that reduced the survival to 37% relative to untreated controls, the acetyltransferase expressing lines Showed similar to 1000-fold increase in sensitivity to the killing effects of IQ over the parental UV5P3 cell line. The same dramatic change in sensitivity was also seen in mutation response at the aprt locus and with chromosomal aberrations and sister chromatid exchanges. In contrast, these cell lines showed cytotoxicity to PhIP similar to that of the parental line UV5P3. These results suggest that PhIP does not require acetyltransferase for metabolic activation leading to genotoxicity in these cells. These new cell lines constitute a sensitive cell system for assessing genotoxicity of compounds requiring metabolic activation by both P4501A2 and acetyltransferase, as well as for studying the molecular processes by which DNA damage can lead to mutation and cancer. RP Wu, RW (reprint author), LAWRENCE LIVERMORE NATL LAB, BIOL & BIOTECHNOL RES PROGRAM, POB 808, LIVERMORE, CA 94551 USA. FU NCI NIH HHS [CA55861] NR 55 TC 33 Z9 33 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1383-5718 EI 1879-3592 J9 MUTAT RES-GEN TOX EN JI Mutat. Res. Genet. Toxicol. Environ. Mutagen. PD APR 24 PY 1997 VL 390 IS 1-2 BP 93 EP 103 DI 10.1016/S0165-1218(97)00005-0 PG 11 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA WV937 UT WOS:A1997WV93700012 PM 9150757 ER PT J AU Kiryukhin, V Casa, D Hill, JP Keimer, B Vigliante, A Tomioka, Y Tokura, Y AF Kiryukhin, V Casa, D Hill, JP Keimer, B Vigliante, A Tomioka, Y Tokura, Y TI An X-ray-induced insulator-metal transition in a magnetoresistive manganite SO NATURE LA English DT Article ID NEUTRON-DIFFRACTION; RESISTIVITY; OXIDE; FILMS AB Manganese oxides of the general formula A(1-x)B(x)MnO(3) (where A and B are trivalent and divalent cations, respectively) have recently attracted considerable attention by virtue of their unusual magnetic and electronic properties(1-9). For example, in some of these materials magnetic fields can drive insulator-to-metal transitions where both the conductivity and magnetization change dramatically-an effect termed 'colossal magneto-resistance'(1-3)-raising hopes for application of these materials in the magnetic recording industry(1-9). Here we show that in one such compound, Pr(0.7)Ca(0.3)Mn0(3), a transition from the insulating antiferromagnetic state to the metallic ferromagnetic state can be driven by illumination with X-rays at low temperatures (<40 K), This transition is accompanied by significant changes in the lattice structure, and can be reversed by thermal cycling, This effect, undoubtedly a manifestation of the strong electron-lattice interactions believed to be responsible for the magnetoresistive properties of these materials(6-9), provides insights into the physical mechanisms of persistent photoconductivity, and may also find applications in X-ray detection and X-ray lithographic patterning of ferromagnetic nanostructures. C1 PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. JOINT RES CTR ATOM TECHNOL,TSUKUBA,IBARAKI 305,JAPAN. UNIV TOKYO,DEPT APPL PHYS,TOKYO 113,JAPAN. RI Tokura, Yoshinori/C-7352-2009; Casa, Diego/F-9060-2016 NR 15 TC 371 Z9 380 U1 8 U2 63 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 24 PY 1997 VL 386 IS 6627 BP 813 EP 815 DI 10.1038/386813a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WV706 UT WOS:A1997WV70600048 ER PT J AU Volkow, ND Wang, GJ Fischman, MW Foltin, RW Fowler, JS Abumrad, NN Vitkun, S Logan, J Gatley, SJ Pappas, N Hitzemann, R Shea, CE AF Volkow, ND Wang, GJ Fischman, MW Foltin, RW Fowler, JS Abumrad, NN Vitkun, S Logan, J Gatley, SJ Pappas, N Hitzemann, R Shea, CE TI Relationship between subjective effects of cocaine and dopamine transporter occupancy SO NATURE LA English DT Article ID NUCLEUS-ACCUMBENS; MOLECULAR MECHANISMS; BINDING-SITES; PET; INHIBITORS; INVIVO; HUMANS; DRUGS; BRAIN AB Cocaine is believed to work by blocking the dopamine transporter (DAT) and thereby increasing the availability of free dopamine within the brain(1-4). Although this concept is central to current cocaine research and to treatment development, a direct relationship between DAT blockade and the subjective effects of cocaine has not been demonstrated in humans. We have used positron emission tomography to determine what level of DAT occupancy is required to produce a subjective 'high' in human volunteers who regularly abuse cocaine. We report here that intravenous cocaine at doses commonly abused by humans (0.3-0.6 mg kg(-1)) blocked between 60 and 77% of DAT sites in these subjects. The magnitude of the self-reported high was correlated with the degree of DAT occupancy, and at least 47% of the transporters had to be blocked for subjects to perceive cocaine's effects. Furthermore, the time course for the high paralleled that of cocaine concentration within the striatum, a brain region implicated in the control of motivation and reward. This is the first demonstration in humans that the doses used by cocaine abusers lead to significant blockade of DAT, and that this blockade is associated with the subjective effects of cocaine. Although these findings provide justification to target the DAT for medication development they suggest that for drugs to be effective in blocking cocaine's effects they would have to be given at doses that achieve almost complete DAT occupancy. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. SUNY STONY BROOK,DEPT PSYCHIAT,STONY BROOK,NY 11794. SUNY STONY BROOK,DEPT ANESTHESIOL,STONY BROOK,NY 11794. COLUMBIA UNIV,DEPT PSYCHIAT,NEW YORK,NY 10032. N SHORE UNIV HOSP,DEPT SURG,MANHASSET,NY 11030. RP Volkow, ND (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 24 TC 429 Z9 438 U1 2 U2 25 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 24 PY 1997 VL 386 IS 6627 BP 827 EP 830 DI 10.1038/386827a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WV706 UT WOS:A1997WV70600053 PM 9126740 ER PT J AU Volkow, ND Wang, GJ Fowler, JS Logan, J Gatley, SJ Hitzemann, R Chen, AD Dewey, SL Pappas, N AF Volkow, ND Wang, GJ Fowler, JS Logan, J Gatley, SJ Hitzemann, R Chen, AD Dewey, SL Pappas, N TI Decreased striatal dopaminergic responsiveness in detoxified cocaine-dependent subjects SO NATURE LA English DT Article ID HUMAN BRAIN; C-11 RACLOPRIDE; THALAMIC NUCLEUS; FRONTAL-LOBE; BINDING; PET; DRUGS; ADDICTION; RECEPTORS; ABUSERS AB Cocaine blocks the reuptake of dopamine, a neurotransmitter involved in the control of movement, cognition, motivation and reward. This leads to an increase in extracellular dopamine; the reinforcing effect of cocaine is associated with elevated dopamine levels in the nucleus accumbens(1,2). But addiction to cocaine involves other effects, such as craving, loss of control and compulsive drug intake; the role of the dopamine system in these effects is less well-understood. We therefore used positron emission tomography (PET) to compare the responses of cocaine addicts and normal controls to intravenous methylphenidate, a drug that, like cocaine, causes an increase in synaptic dopamine(3). Addicts showed reduced dopamine release in the striatum, the brain region where the nucleus accumbens is located, and also had a reduced 'high' relative to controls. In contrast, addicts showed an increased response to methylphenidate in the thalamus (a region that conveys sensory input to the cortex). This thalamic response was associated with cocaine craving and was not seen in control subjects. Thus, our findings challenge the notion that addiction involves an enhanced striatal dopamine response to cocaine and/or an enhanced induction of euphoria. Moreover, they suggest a participation of thalamic dopamine pathways in cocaine addiction, a possibility that merits further investigation. C1 BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. SUNY STONY BROOK, DEPT PSYCHIAT, STONY BROOK, NY 11794 USA. RP Volkow, ND (reprint author), BROOKHAVEN NATL LAB, DEPT MED, UPTON, NY 11973 USA. NR 30 TC 521 Z9 528 U1 0 U2 21 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON, ENGLAND N1 9XW SN 0028-0836 J9 NATURE JI Nature PD APR 24 PY 1997 VL 386 IS 6627 BP 830 EP 833 DI 10.1038/386830a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WV706 UT WOS:A1997WV70600054 PM 9126741 ER PT J AU Dean, DJ Koonin, SE Langanke, K Radha, PB AF Dean, DJ Koonin, SE Langanke, K Radha, PB TI Rotational and pairing properties of Rb-74 SO PHYSICS LETTERS B LA English DT Article ID NUCLEAR SHELL-MODEL; MONTE-CARLO; FE-54 AB We use a cranked shell model Monte Carlo (SMMC) approach to study rotational properties and pair correlations in the odd-odd N = Z nucleus Rb-74. The calculation is performed in the complete 1p-0f(5/2)-0g(9/2) model space with a residual interaction derived from the Paris potential, The calculated ground state is dominated by isovector J = 0 proton-neutron (pn) pairing. With increasing frequency the J = 0 pn correlations decrease to a constant value at around [J] = 3 +/- 1.5 (h) over bar, while the isoscalar pn correlations (mainly J = 9) increase, Relatedly, the isospin decreases with frequency from its ground state value T = 1 as isoscalar correlations set in. This finding is in agreement with experiment, where at higher rotational frequency a T = 0 band becomes energetically favored over the T = 1 ground state band. (C) 1997 Published by Elsevier Science B.V. C1 CALTECH,WK KELLOGG RADIAT LAB,PASADENA,CA 91125. AARHUS UNIV,INST PHYS & ASTRON,AARHUS,DENMARK. RP Dean, DJ (reprint author), OAK RIDGE NATL LAB,DIV PHYS,POB 2008,OAK RIDGE,TN 37831, USA. OI Dean, David/0000-0002-5688-703X NR 22 TC 59 Z9 59 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 24 PY 1997 VL 399 IS 1-2 BP 1 EP 7 DI 10.1016/S0370-2693(97)00275-X PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV815 UT WOS:A1997WV81500001 ER PT J AU Kalinovsky, Y Mitchell, KL Roberts, CD AF Kalinovsky, Y Mitchell, KL Roberts, CD TI K-l3 and pi(e3) transition form factors SO PHYSICS LETTERS B LA English DT Article DE electroweak interactions; semileptonic decays, fK(l3)(t), f pi(e3)(t); Dyson-Schwinger equations; confinement; nonperturbative QCD; quark models AB K-l3 and pi(e3) transition form factors are calculated as an application of Dyson-Schwinger equations. A heuristic one-parameter model of the quark-W-boson vertex is used to highlight their sensitivity to the form of this vertex, The K-l3 form factors, f(+/-)(K), are approximately linear on t is an element of [m(e)(2), m(mu)(2)] and f(+)(K')(0) similar to f(-)(K')(0).f(-)(K)(0) is a measure of the Euclidean constituent-quark mass ratio: M-s(E)/M-u(E). In the isospin symmetric limit: -f(+)(pi)(0) = F-pi(t), the electromagnetic pion form factor, and f(-)(pi) (t) = 0. (C) 1997 Published by Elsevier Science B.V. C1 TRIUMF,VANCOUVER,BC V6T 2A3,CANADA. ARGONNE NATL LAB,ARGONNE,IL 60439. RP Kalinovsky, Y (reprint author), JOINT INST NUCL RES,BOGOLIUBOV LAB THEORET PHYS,DUBNA 141980,RUSSIA. NR 20 TC 18 Z9 18 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 24 PY 1997 VL 399 IS 1-2 BP 22 EP 28 DI 10.1016/S0370-2693(97)00271-2 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV815 UT WOS:A1997WV81500004 ER PT J AU Hisano, J Kiyoura, S Murayama, H AF Hisano, J Kiyoura, S Murayama, H TI Upper bound on R-b in two Higgs doublet model from lepton universality SO PHYSICS LETTERS B LA English DT Article ID SUPERSYMMETRIC STANDARD MODEL; ELECTROWEAK PRECISION DATA; DECAY; MASS; QCD AB It has been known that R-b can be enhanced in the two Higgs doublet model if tan beta is large, We point out that a similar enhancement in Gamma(Z --> tau(+)tau(-)) is large enough to place a constraint on such a possibility. We obtain a 95% CL upper bound Delta R-b/R-b < 0.73% in this model for the <(MS)over bar> mass m(b)(m(z)) = 3.0 GeV. The 1996 world average is Delta R-b/R-b = 0.97% +/- 0.51%. We used the m(b)(m(z)) to determine the bottom Yukawa coupling instead of m(b)(m(b)) unlike in previous analyses, and also an improved experimental test of the lepton universality in Z decay, which made our results qualitatively different. (C) 1997 Elsevier Science B.V. C1 TOKYO INST TECHNOL, DEPT PHYS, MEGURO KU, TOKYO 152, JAPAN. NATL LAB HIGH ENERGY PHYS, TSUKUBA, IBARAKI 305, JAPAN. UNIV CALIF BERKELEY, DEPT PHYS, BERKELEY, CA 94720 USA. UNIV CALIF BERKELEY, ERNEST ORLANDO LAWRENCE BERKELEY NATL LAB, THEORET PHYS GRP, BERKELEY, CA 94720 USA. RP UNIV MINNESOTA, SCH PHYS & ASTRON, 116 CHURCH ST SE, MINNEAPOLIS, MN 55455 USA. RI Murayama, Hitoshi/A-4286-2011 NR 42 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD APR 24 PY 1997 VL 399 IS 1-2 BP 156 EP 162 DI 10.1016/S0370-2693(97)00259-1 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV815 UT WOS:A1997WV81500024 ER PT J AU Stoll, SL Bornick, RM Stacy, AM VerNooy, PD AF Stoll, SL Bornick, RM Stacy, AM VerNooy, PD TI Copper K-edge x-ray absorption studies of La2-xKxCuO4 superconductors, Ba4NaCuO4(CO3)(2), and NdCu2O4 SO INORGANIC CHEMISTRY LA English DT Article ID SINGLE-CRYSTALS; VALENCE; SPECTRA; STATE; SPECTROSCOPY; COORDINATION; OXYGEN; XANES; MODEL; CU AB X-ray near-edge absorption spectroscopy (XANES) measurements are reported at the Cu K-edge for La2-xKxCuO4 superconductors with x = 0.1 and 0.2. Comparisons of the data were made with the absorption spectra of a Cu(II) standard (La2CuO4), a new Cu(III) standard (Ba4NaCuO4(CO3)(2)), and a new mixed-valent Cu(II)/Cu(III) phase (NdCu2O4). There is a consistent increase in the energy of the main Cu absorption edge in the following series: La2CuO4 < La1.9K0.1CuO4 < La1.8K0.2CuO4 similar to NdCu2O4 < Ba4NaCuO4(CO3)(2). This trend can be attributed to an increase in the average Cu valence and to a decrease in bond length and an increase in covalency. The magnitude of the energy shift from Cu(II) to Cu(III) for the main absorption edge is similar to 3 eV. There is no measurable change in the energy of the pre-edge feature irrespective of Cu valence. Furthermore, no new features appear at the edge for samples with formal oxidation state between 2 and 3, even for NdCu2O4, which contains both Cu(II) and Cu(III) in crystallographically distinct sites. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. DUPONT CO INC,CENT RES & DEV,EXPT STN,WILMINGTON,DE 19880. NR 27 TC 12 Z9 12 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD APR 23 PY 1997 VL 36 IS 9 BP 1838 EP 1841 DI 10.1021/ic960424n PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA WW128 UT WOS:A1997WW12800018 ER PT J AU Cunningham, MA Ho, LL Nguyen, DT Gillilan, RE Bash, PA AF Cunningham, MA Ho, LL Nguyen, DT Gillilan, RE Bash, PA TI Simulation of the enzyme reaction mechanism of malate dehydrogenase SO BIOCHEMISTRY LA English DT Article ID DENSITY-FUNCTIONAL CALCULATIONS; EMPIRICAL ENERGY FUNCTION; TRIOSEPHOSPHATE ISOMERASE; LACTATE-DEHYDROGENASE; AQUEOUS-SOLUTION; POTENTIAL FUNCTIONS; TRANSITION-STATE; COMBINED QUANTUM; TERNARY COMPLEX; RATE CONSTANTS AB A hybrid numerical method, which employs molecular mechanics to describe the bulk of the solvent-protein matrix and a semiempirical quantum-mechanical treatment for atoms near the reactive site, was utilized to simulate the minimum energy surface and reaction pathway for the interconversion of malate and oxaloacetate catalyzed by the enzyme malate dehydrogenase (MDH). A reaction mechanism for proton and hydride transfers associated with MDH and cofactor nicotinamide adenine dinucleotide (NAD) is deduced from the topology of the calculated energy surface. The proposed mechanism consists of (1) a sequential reaction with proton transfer preceding hydride transfer (malate to oxaloacetate direction), (2) the existence of two transition states with energy barriers of approximately 7 and 15 kcal/mol for the proton and hydride transfers, respectively, and (3) reactant (malate) and product (oxaloacetate) states that are nearly isoenergetic. Simulation analysis of the calculated energy profile shows that solvent effects due to the protein matrix dramatically alter the intrinsic reactivity of the functional groups involved in the MDH reaction, resulting in energetics similar to that found in aqueous solution. An energy decomposition analysis indicates that specific MDH residues (Arg-81, Arg-87, Asn-119, Asp-150, and Arg-153) in the vicinity of the substrate make significant energetic contributions to the stabilization of proton transfer and destabilization of hydride transfer. This suggests that these amino acids play an important role in the catalytic properties of MDH. C1 ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,ARGONNE,IL 60439. MA CUNNINGHAM ASSOCIATES,NORTHBROOK,IL 60062. INPHARMAT CORP,SAN DIEGO,CA 92126. CORNELL UNIV,CTR THEORY,ITHACA,NY 14853. YALE UNIV,DEPT PHYS,NEW HAVEN,CT 06511. NR 57 TC 62 Z9 62 U1 2 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD APR 22 PY 1997 VL 36 IS 16 BP 4800 EP 4816 DI 10.1021/bi962734n PG 17 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA WV345 UT WOS:A1997WV34500011 PM 9125501 ER PT J AU Cheng, BM Preses, JM Grover, JR AF Cheng, BM Preses, JM Grover, JR TI Photoionization of C2F4/O-2 complexes and C2F4 homoclusters SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTO-IONIZATION; VANDERWAALS COMPLEXES; GAS-PHASE; VIBRATIONAL PREDISSOCIATION; DISSOCIATION-ENERGIES; INFRARED-SPECTRUM; ORGANIC-MOLECULES; BINDING-ENERGIES; NEUTRAL DIMERS; SULFUR-DIOXIDE AB Single-photon ionization of the clusters C2F4 . O-2, (C2F4)(2)O-2, (C2F4)(2), and (C2F4)(3) is reported for energies up to 25 eV. The ionization potentials found are IP(C2F4 . O-2)=9.879+/-0.01 1 eV, IP([C2F4](2)O-2)=9.776+/-0.016 eV, IP([C2F4](2))=9.826+/-0.017 eV, and IP([C2F4](3))=9.838+/-0.022 eV. In addition, we measured IP(C2F4)=10.117+/-0.004 eV, in excellent agreement with Drier work. The appearance potential of C2F4+ from C2F4 . O-2 was found to be AP=10.253+/-0.012 eV, which, when combined with appropriate values from above gives the cluster dissociation energies D-0(C2F4 . O-2)=0.136+/-0.013 eV (3.14+/-0.29 kcal mol(-1)), and D-0([C2F4 . O-2](+))=0.374+/-0.016 eV (8.62+/-0.38 kcal mol(-1)). The former value helps to understand the remarkable solubility of oxygen in fluorocarbons. No evidence was seen for photoionization-induced reactions of O-2 with C2F4. A surprisingly intense Rydberg progression converging to the excited state of C2F4+ near 16.0 eV can be identified in the parent C2F4, and persists strongly in all four of the clusters studied. The lack of oxygen-containing reaction products and the persistence of the Rydberg state convey information about the structure of C2F4 . O-2. (C) 1997 American Institute of Physics. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. NR 71 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 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 22 PY 1997 VL 106 IS 16 BP 6698 EP 6708 DI 10.1063/1.473667 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WV166 UT WOS:A1997WV16600020 ER PT J AU Raghavachari, K Stefanov, BB Curtiss, LA AF Raghavachari, K Stefanov, BB Curtiss, LA TI Accurate thermochemistry for larger molecules: Gaussian-2 theory with bond separation energies SO JOURNAL OF CHEMICAL PHYSICS LA English DT Letter ID SET MODEL CHEMISTRY; 2ND-ROW COMPOUNDS; 1ST-ROW AB Gaussian-2 (G2) theory is combined with isodesmic bond separation reaction energies to yield accurate thermochemistry for larger molecules. For a test set of 40 Molecules composed of H, C, O, and N, our method yields enthalpies of formation, Delta H-f(0)(298 K), with a mean absolute deviation from experiment of only 0.5 kcal/mol. This is an improvement of a factor of three over the deviation of 1.5 kcal/mol seen in standard G2 theory. (C) 1997 American Institute of Physics. C1 ARGONNE NATL LAB,DIV MAT SCI,DIV CHEM TECHNOL,ARGONNE,IL 60439. RP Raghavachari, K (reprint author), AT&T BELL LABS,LUCENT TECHNOL,600 MT AVE,MURRAY HILL,NJ 07974, USA. RI Stefanov, Boris/E-8905-2012 NR 28 TC 164 Z9 164 U1 1 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 22 PY 1997 VL 106 IS 16 BP 6764 EP 6767 DI 10.1063/1.473659 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WV166 UT WOS:A1997WV16600026 ER PT J AU Christen, HM Boatner, LA Budai, JD Chisholm, MF Gerber, C Urbanik, M AF Christen, HM Boatner, LA Budai, JD Chisholm, MF Gerber, C Urbanik, M TI Semiconducting epitaxial films of metastable SrRu0.5Sn0.5O3 grown by pulsed laser deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID TRANSITION; CRYSTALS AB Synthesis of the perovskite solid solution that forms between metallic SrRuO3 and insulating SrSnO3 is reported. This material is proposed as a conducting thin-film electrode/epitaxial-substrate material. While the bulk solid solution could not be formed, thin films of single-phase SrRu0.5Sn0.5O3 were grown on (001) KTaO3 single-crystal substrates by pulsed laser deposition. These films exhibit a commensurate in-plane lattice match with KTaO3 (a=3.989 Angstrom); accordingly, the lattice constant of SrRu0.5Sn0.5O3 is larger than that of commonly used conducting-oxide thin-film electrodes (e.g., SrRuO3, LaNiO3, and YBa2CU3O7-delta). The SrRu0.5Sn0.5O3 films were analyzed using x-ray diffraction. Rutherford backscattering, atomic force microscopy, Z-contrast transmission electron microscopy, and Hall effect measurements. The results revealed excellent atomic-scale structural properties, flat surfaces (13 Angstrom rms roughness), and p-type conduction with a room-temperature resistivity of 16 m Ohm cm. (C) 1997 American Institute of Physics. C1 IBM CORP,DIV RES,ZURICH RES LAB,CH-8803 RUSCHLIKON,SWITZERLAND. COMMERCIAL CRYSTAL LABS INC,NAPLES,FL 33942. RP Christen, HM (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. RI Gerber, Christoph/G-4851-2011; Christen, Hans/H-6551-2013; Boatner, Lynn/I-6428-2013; Budai, John/R-9276-2016 OI Christen, Hans/0000-0001-8187-7469; Boatner, Lynn/0000-0002-0235-7594; Budai, John/0000-0002-7444-1306 NR 17 TC 20 Z9 20 U1 1 U2 18 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 21 PY 1997 VL 70 IS 16 BP 2147 EP 2149 DI 10.1063/1.119082 PG 3 WC Physics, Applied SC Physics GA WU601 UT WOS:A1997WU60100028 ER PT J AU Krauss, SW Larabell, CA Lockett, S Gascard, P Penman, S Mohandas, N Chasis, JA AF Krauss, SW Larabell, CA Lockett, S Gascard, P Penman, S Mohandas, N Chasis, JA TI Structural protein 4.1 in the nucleus of human cells: Dynamic rearrangements during cell division SO JOURNAL OF CELL BIOLOGY LA English DT Article ID MEMBRANE SKELETAL PROTEIN-4.1; SPECTRIN-ACTIN BINDING; DNA POLYMERASE-DELTA; PRE-MESSENGER-RNA; ERYTHROCYTE PROTEIN-4.1; GLYCOPHORIN-C; ELECTRON-MICROSCOPY; MAMMALIAN NUCLEUS; MONOCLONAL-ANTIBODIES; AUXILIARY PROTEIN AB Structural protein 4.1, first identified as a crucial 80-kD protein in the mature red cell membrane skeleton, is now known to be a diverse family of protein isoforms generated by complex alternative mRNA splicing, variable usage of translation initiation sites, and posttranslational modification. Protein 4.1 epitopes are detected at multiple intracellular sites in nucleated mammalian cells. We report here investigations of protein 4.1 in the nucleus. Reconstructions of optical sections of human diploid fibroblast nuclei using antibodies specific for 80-kD red cell 4.1 and for 4.1 peptides showed 4.1 immunofluorescent signals were intranuclear and distributed throughout the volume of the nucleus. After sequential extractions of cells in situ, 4.1 epitopes were detected in nuclear matrix both by immunofluorescence light microscopy and resinless section immunoelectron microscopy. Western blot analysis of fibroblast nuclear matrix protein fractions, isolated under identical extraction conditions as those for microscopy, revealed several polypeptide bands reactive to multiple 4.1 antibodies against different domains. Epitope-tagged protein 4.1 was detected in fibroblast nuclei after transient transfections using a construct encoding red cell 80-kD 4.1 fused to an epitope tag. Endogenous protein 4.1 epitopes were detected throughout the cell cycle but underwent dynamic spatial rearrangements during cell division. Protein 4.1 was observed in nucleoplasm and centrosomes at interphase, in the mitotic spindle during mitosis, in perichromatin during telophase, as well as in the midbody during cytokinesis. These results suggest that multiple protein 4.1 isoforms may contribute significantly to nuclear architecture and ultimately to nuclear function. C1 MIT,DEPT BIOL,CAMBRIDGE,MA 02139. RP Krauss, SW (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,MS 74-157,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. FU NIDDK NIH HHS [P01 DK032094, DK 32094] NR 95 TC 96 Z9 97 U1 0 U2 2 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 SN 0021-9525 J9 J CELL BIOL JI J. Cell Biol. PD APR 21 PY 1997 VL 137 IS 2 BP 275 EP 289 DI 10.1083/jcb.137.2.275 PG 15 WC Cell Biology SC Cell Biology GA WW014 UT WOS:A1997WW01400002 PM 9128242 ER PT J AU Jiang, XW Fishman, RS AF Jiang, XW Fishman, RS TI Coupled spin- and charge-density waves in chromium alloys SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID PHASE-DIAGRAM; IMPURITIES AB Both the spin- and charge-density waves in Cr alloys are produced by the Coulomb attraction between electrons and holes on two nested Fermi surfaces. The Coulomb interaction responsible for the charge-density wave increases the energy splining between quasiparticles which are strongly and weakly bound to the spin-density wave. if the splitting is sufficiently large, the paramagnetic-to-commensurate transition becomes strongly first order, as observed in CrFe and CrSi alloys. C1 N DAKOTA STATE UNIV,DEPT PHYS,FARGO,ND 58105. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Fishman, Randy/C-8639-2013 NR 25 TC 13 Z9 13 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL, ENGLAND BS1 6BE SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD APR 21 PY 1997 VL 9 IS 16 BP 3417 EP 3426 DI 10.1088/0953-8984/9/16/013 PG 10 WC Physics, Condensed Matter SC Physics GA WW477 UT WOS:A1997WW47700013 ER PT J AU Edler, KJ Reynolds, PA Branton, PJ Trouw, FR White, JW AF Edler, KJ Reynolds, PA Branton, PJ Trouw, FR White, JW TI Structure and dynamics of hydrogen sorption in mesoporous MCM-41 SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID CUBIC PHASES; NEUTRON-SCATTERING; LIPID SYSTEMS; SURFACTANT AB Adsorption isotherms taken at temperatures ranging from 20 to 77 K show a large pore volume and surface area of 980 m(2) g(-1) for the physical adsorption of molecular hydrogen on MCM-41. The adsorbed hydrogen behaves more like a solid than a liquid and isosteric heats of adsorption reveal a heterogenous surface. The evaporation behaviour of the adsorbed hydrogen indicates that the hexagonally packed tubes in MCM-41 may be effectively interconnected into a single void space. Neutron inelastic scattering shows that molecular hydrogen exists in two sites in the pores of MCM-41. We designate as surface states those with a variety of weakly hindered rotational excitations centred at 11.8(2) meV and as bulk states, at high doping of H-2, those which have narrow rotational excitations at 14.7(3) meV. These excitations are hardly changed from those of the free crystal in energy, energy width or momentum transfer dependence. Each type accounts for ca. 50% of the total pore volume. Strong hydrogen recoil scattering is also observed at momentum transfers above ca. 3 Angstrom(-1). Neutron diffraction from the filled sample at 1.9 K shows a single peak at 3.1 Angstrom, characteristic of the H-2-H-2 correlations in bulk hydrogen. This peak is much weaker for the surface adsorbed species. The concentration dependence of this peak also shows a 1:1 division of void space between surface-adsorbed and bulk-like species. In addition we observe a separate peak at 14.38(3) Angstrom, the hexagonal (21) of MCM-41 involving the silica framework, whose diffracted intensity changes dramatically with hydrogen doping, in a way inconsistent with a smooth walled, hexagonally packed mesopore. These data, together with previous X-ray diffraction data, provide information on silica density, absorbing surface and free volume projected onto the basal plane. The detail and complexity of the projection were unexpected. The data agree well with a model for which the silica in the walls is loosely interwoven, and occupies only 40% of the wall volume. The 35% silica surrounding the empty 7 Angstrom hole as a 12.7 Angstrom lining has a projected density of ca. 90% that of the walls. Either highly divided, 'hairy' walls or a structure like a highly defective variant of the MCM-48 structure would fit the data. The projection of smooth-walled but highly twisted channels onto a horizontal plane could give a density distribution equivalent to the highly porous silicate walls in straight channels. C1 AUSTRALIAN NATL UNIV,RES SCH CHEM,CANBERRA,ACT 0200,AUSTRALIA. ARGONNE NATL LAB,INTENSE PULSED NEUTRON SOURCE,ARGONNE,IL 60439. RI Edler, Karen/A-7324-2011 OI Edler, Karen/0000-0001-5822-0127 NR 39 TC 34 Z9 34 U1 0 U2 6 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD APR 21 PY 1997 VL 93 IS 8 BP 1667 EP 1674 DI 10.1039/a607878h PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WW480 UT WOS:A1997WW48000030 ER PT J AU Gingrich, DM Greeniaus, G Kitching, P Olsen, B Pinfold, JL Rodning, NL Boos, E Zhautykov, BO Aubert, B Bazan, A Beaugiraud, B Boniface, J Colas, J Jezequel, S Leflour, T Maire, M Rival, F Stipcevic, M Thion, J VandenPlas, D WingerterSeez, I Zitoun, R Zolnierowski, YP Chmeissani, M Fernandez, E Garrido, L Martinez, M Padilla, C Gordon, HA Radeka, V Rahm, D Stephani, D Baisin, L Berset, JC Chevalley, JL Gianotti, F Gildemeister, O Marin, CP Nessi, M Poggioli, L Richter, W Vuillemin, V Baze, JM Gosset, L Lavocat, P Lottin, JP Mansoulie, B Meyer, JP Renardy, JF Schwindling, J Teiger, J Collot, J deSaintignon, P Dzahini, D Hostachy, JY Laborie, G Mahout, G Merchez, E Pouxe, J Hervas, L Labarga, L Scheel, CV Chekhtman, A Dargent, P Dinkespiller, B Etienne, F Fassnacht, P Fouchez, D Martin, L Martin, O Miotto, A Monnier, E Nagy, E Olivetto, C Tisserant, S Battistoni, G Camin, DV Cavalli, D Costa, G Cozzi, L Cravero, A Fedyakin, N Ferrari, A Mandelli, L Mazzanti, M Perini, L Sala, P Azuelos, G Beaudoin, G Depommier, P LeonFlorian, E Leroy, C Roy, P Seman, M Auge, E Chase, R Chollet, JC deLaTaille, C Fayard, L Fournier, D Hrisoho, A Merkel, B Noppe, JM Parrour, G Petroff, P Schaffer, A SeguinMoreau, N Serin, L Tisserand, V Vichou, I Canton, B David, J Genat, JF Imbault, D LeDortz, O SavoyNavarro, A Schwemling, P Eek, LO LundJensen, B Soderqvist, J Lefebvre, M Robertson, S White, J AF Gingrich, DM Greeniaus, G Kitching, P Olsen, B Pinfold, JL Rodning, NL Boos, E Zhautykov, BO Aubert, B Bazan, A Beaugiraud, B Boniface, J Colas, J Jezequel, S Leflour, T Maire, M Rival, F Stipcevic, M Thion, J VandenPlas, D WingerterSeez, I Zitoun, R Zolnierowski, YP Chmeissani, M Fernandez, E Garrido, L Martinez, M Padilla, C Gordon, HA Radeka, V Rahm, D Stephani, D Baisin, L Berset, JC Chevalley, JL Gianotti, F Gildemeister, O Marin, CP Nessi, M Poggioli, L Richter, W Vuillemin, V Baze, JM Gosset, L Lavocat, P Lottin, JP Mansoulie, B Meyer, JP Renardy, JF Schwindling, J Teiger, J Collot, J deSaintignon, P Dzahini, D Hostachy, JY Laborie, G Mahout, G Merchez, E Pouxe, J Hervas, L Labarga, L Scheel, CV Chekhtman, A Dargent, P Dinkespiller, B Etienne, F Fassnacht, P Fouchez, D Martin, L Martin, O Miotto, A Monnier, E Nagy, E Olivetto, C Tisserant, S Battistoni, G Camin, DV Cavalli, D Costa, G Cozzi, L Cravero, A Fedyakin, N Ferrari, A Mandelli, L Mazzanti, M Perini, L Sala, P Azuelos, G Beaudoin, G Depommier, P LeonFlorian, E Leroy, C Roy, P Seman, M Auge, E Chase, R Chollet, JC deLaTaille, C Fayard, L Fournier, D Hrisoho, A Merkel, B Noppe, JM Parrour, G Petroff, P Schaffer, A SeguinMoreau, N Serin, L Tisserand, V Vichou, I Canton, B David, J Genat, JF Imbault, D LeDortz, O SavoyNavarro, A Schwemling, P Eek, LO LundJensen, B Soderqvist, J Lefebvre, M Robertson, S White, J TI Performance of an endcap prototype of the ATLAS accordion electromagnetic calorimeter SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE calorimetry; liquid-argon; ATLAS AB The design and construction of a lead-liquid-argon endcap calorimeter prototype using an accordion geometry and conceived as a sector of the inner wheel of the endcap calorimeter of the future ATLAS experiment al the LHC is described. The performance obtained using electron beam data is presented. The main results are energy resolution with a sampling term below 11%/root E(GeV) and a small local constant term, good linearity of the response with the incident energy and a global constant term of 0.8% over an extended area in the rapidity range 2.2 < eta < 2.9. These properties make the design suitable for the ATLAS electromagnetic endcap calorimeter. C1 CPPM,MARSEILLE,FRANCE. UNIV ALBERTA,EDMONTON,AB,CANADA. HEPI,ALMA ATA,KAZAKHSTAN. LAPP,ANNECY LE VIEUX,FRANCE. UNIV AUTONOMA BARCELONA,BELLATERRA,SPAIN. BROOKHAVEN NATL LAB,UPTON,NY 11973. CERN,GENEVA,SWITZERLAND. CTR ETUD SACLAY,CEA,DSM,DAPNIA,SPP,F-91191 GIF SUR YVETTE,FRANCE. ISN,GRENOBLE,FRANCE. UNIV AUTONOMA MADRID,MADRID,SPAIN. UNIV MILAN,DIPARTIMENTO FIS,MILAN,ITALY. IST NAZL FIS NUCL,I-20133 MILAN,ITALY. UNIV MONTREAL,MONTREAL,PQ,CANADA. COLUMBIA UNIV,NEVIS LAB,IRVINGTON,NY. LAL,ORSAY,FRANCE. UNIV PARIS 06,LPHE,F-75252 PARIS 05,FRANCE. UNIV PARIS 07,LPHE,F-75221 PARIS 05,FRANCE. ROYAL INST TECHNOL,S-10044 STOCKHOLM,SWEDEN. UNIV VICTORIA,VICTORIA,BC,CANADA. RI Boos, Eduard/D-9748-2012; sala, paola/E-2868-2013; Chmeissani, Mokhtar/G-4346-2015; Fernandez, Enrique/L-5387-2014; OI sala, paola/0000-0001-9859-5564; Chmeissani, Mokhtar/0000-0002-2287-4791; Fernandez, Enrique/0000-0002-6405-9488; Garrido Beltran, Lluis/0000-0001-8883-6539 NR 10 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 21 PY 1997 VL 389 IS 3 BP 398 EP 408 DI 10.1016/S0168-9002(97)00328-8 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ495 UT WOS:A1997XJ49500002 ER PT J AU Nanal, V Back, BB Hofman, DJ AF Nanal, V Back, BB Hofman, DJ TI Temperature dependence of BaF2 scintillation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID LUMINESCENCE; CRYSTAL AB The scintillation characteristics of BaF2 excited by gamma-ray irradiation is studied as a function of temperature in the range -50 - +27 degrees C. We find evidence for three scintillation decay components with different temperature dependencies. A fast scintillation component with a decay time of similar to 800 ps is independent of temperature, a slow component increases from 1 mu s at +27 degrees C to 5 mu s at -50 degrees C and a third slow component with a decay time of similar to 0.4 mu s becomes clearly visible at low temperatures. The scintillation light intensity of the fast component stays constant over the entire temperature range studied, whereas that of the slow component increases by a factor of two when cooling from room temperature to -25 degrees C. However, further cooling causes a decrease in the scintillation light intensity. The increased light output results in an improved energy resolution for low-energy gamma-rays. C1 ARGONNE NATL LAB, DIV PHYS, ARGONNE, IL 60439 USA. NR 11 TC 5 Z9 7 U1 0 U2 4 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 APR 21 PY 1997 VL 389 IS 3 BP 430 EP 436 DI 10.1016/S0168-9002(97)00326-4 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ495 UT WOS:A1997XJ49500006 ER PT J AU Schieber, M Lund, JC Olsen, RW McGregor, DS VanScyoc, JM James, RB Soria, E AF Schieber, M Lund, JC Olsen, RW McGregor, DS VanScyoc, JM James, RB Soria, E TI Material properties and room temperature nuclear detector response of wide band gap semiconductors (vol 377, pg 492, 1996) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Correction, Addition C1 SANDIA NATL LABS,ADV ELECT MFG TECHNOL,LIVERMORE,CA 94550. SANDIA NATL LABS,MAT DEV & DIAGNOST,LIVERMORE,CA 94550. MAX PLANCK INST FESTKORPERFORSCH,D-70506 STUTTGART,GERMANY. RP Schieber, M (reprint author), HEBREW UNIV JERUSALEM,FREDY & NADINE HERRMANN GRAD SCH APPL SCI,IL-91904 JERUSALEM,ISRAEL. NR 1 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 21 PY 1997 VL 389 IS 3 BP 523 EP 523 DI 10.1016/S0168-9002(97)00386-0 PG 1 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA XJ495 UT WOS:A1997XJ49500017 ER PT J AU Randrup, J AF Randrup, J TI Mean-field treatment of the linear sigma model in dynamical calculations of DCC observables SO NUCLEAR PHYSICS A LA English DT Article DE disoriented chiral condensates; DCC observables; mean field approximation; dynamical calculations ID DISORIENTED CHIRAL CONDENSATE; PHASE-TRANSITION; HIGH-ENERGY; NUCLEAR COLLISIONS; QUANTUM EVOLUTION; DOMAINS; FORM; QCD AB Approximate mean-field equations of motion for the classical chiral field are developed within the linear a model by means of a Hartree factorization. Both the approximated and the unapproximated equations of motion are augmented with a Rayleigh cooling term to emulate a uniform expansion, thereby allowing the extraction of observables relevant to the detection of disoriented chiral condensates, specifically the pion power spectrum, the pion correlation function, and the distribution of the neutral pion fraction. While the mean-field dynamics appears to be sufficiently accurate to be practically useful, the results also illustrate some difficulties associated with identifying the phenomenon experimentally. (C) 1997 Elsevier Science B.V. RP UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV NUCL SCI, 1 CYCLOTRON RD, BERKELEY, CA 94720 USA. NR 33 TC 47 Z9 47 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 EI 1873-1554 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 21 PY 1997 VL 616 IS 3-4 BP 531 EP 554 DI 10.1016/S0375-9474(97)00003-1 PG 24 WC Physics, Nuclear SC Physics GA WW386 UT WOS:A1997WW38600001 ER PT J AU Bagley, CH Luther, GG AF Bagley, CH Luther, GG TI Preliminary results of a determination of the Newtonian constant of gravitation: A test of the Kuroda hypothesis SO PHYSICAL REVIEW LETTERS LA English DT Article AB Two preliminary determinations of the Newtonian constant of gravitation have been performed at Los Alamos National Laboratory employing low-e torsion pendulums and using the time-of-swing method. Recently, Kuroda has predicted that such determinations have an upward bias inversely proportional to the oscillation Q, and our results support this conjecture. if this conjecture is correct, our best value for the constant is (6.6740 +/- 0.0007) x 10(-11) m(3) kg(-1) s(-2). RP Bagley, CH (reprint author), LOS ALAMOS NATL LAB,DIV PHYS,POB 1663,LOS ALAMOS,NM 87544, USA. NR 12 TC 77 Z9 80 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 21 PY 1997 VL 78 IS 16 BP 3047 EP 3050 DI 10.1103/PhysRevLett.78.3047 PG 4 WC Physics, Multidisciplinary SC Physics GA WU621 UT WOS:A1997WU62100005 ER PT J AU Erler, J Feng, JL Polonsky, N AF Erler, J Feng, JL Polonsky, N TI Wide scalar neutrino resonance and b(b)over-bar production at the CERN collider LEP SO PHYSICAL REVIEW LETTERS LA English DT Article ID R-PARITY BREAKING; CROSS-SECTION ASYMMETRY; Z-BOSON PRODUCTION; E+E COLLISIONS; SUPERSYMMETRY; SIGNATURES; NUMBER AB In supersymmetric models with R-parity violation, scalar neutrinos (v) over tilde may be produced as s-channel resonances in e(+)e(-) colliders. We note that within current constraints the scalar neutrino may have a width of several GeV into and be produced with large cross section, leading to a novel supersymmetry discovery signal at the CERN collider LEP II. In addition, if m((v) over tilde) approximate to m(Z), such a resonance necessarily increases R-b and reduces A(FB)(b), significantly improving the fit to electroweak data. Bounds from B meson and top quark decays are leading constraints, and we stress the importance of future measurements. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. UNIV CALIF SANTA CRUZ,DEPT PHYS,SANTA CRUZ,CA 95064. RUTGERS STATE UNIV,DEPT PHYS & ASTRON,PISCATAWAY,NJ 08855. RP Erler, J (reprint author), UNIV CALIF SANTA CRUZ,SANTA CRUZ INST PARTICLE PHYS,SANTA CRUZ,CA 95064, USA. NR 23 TC 89 Z9 89 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 21 PY 1997 VL 78 IS 16 BP 3063 EP 3066 DI 10.1103/PhysRevLett.78.3063 PG 4 WC Physics, Multidisciplinary SC Physics GA WU621 UT WOS:A1997WU62100009 ER PT J AU Yamada, M Ji, HT Hsu, S Carter, T Kulsrud, R Ono, Y Perkins, F AF Yamada, M Ji, HT Hsu, S Carter, T Kulsrud, R Ono, Y Perkins, F TI Identification of Y-shaped and O-shaped diffusion regions during magnetic reconnection in a laboratory plasma SO PHYSICAL REVIEW LETTERS LA English DT Article ID FIELD; MAGNETOPAUSE AB Two strikingly different shapes of diffusion regions are identified during magnetic reconnection in a magnetohydrodynamic laboratory plasma. The shapes depend on the third vector component of the reconnecting magnetic fields. Without the third component (antiparallel or null-helicity reconnection), a thin double-Y-shaped diffusion region is identified. In this case, the neutral sheet current profile is accurately measured to be as narrow as the order of the ion gyro-radius. In the presence of an appreciable third component (cohelicity reconnection), an O-shaped diffusion region appears and grows into a spheromak configuration. RP Yamada, M (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Carter, Troy/E-7090-2010; Yamada, Masaaki/D-7824-2015; OI Carter, Troy/0000-0002-5741-0495; Yamada, Masaaki/0000-0003-4996-1649; Hsu, Scott/0000-0002-6737-4934 NR 22 TC 61 Z9 62 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 21 PY 1997 VL 78 IS 16 BP 3117 EP 3120 DI 10.1103/PhysRevLett.78.3117 PG 4 WC Physics, Multidisciplinary SC Physics GA WU621 UT WOS:A1997WU62100023 ER PT J AU Hanaguri, T Tsuchiya, Y Sakamoto, S Maeda, A Steel, DG AF Hanaguri, T Tsuchiya, Y Sakamoto, S Maeda, A Steel, DG TI Effects of columnar defects on the Josephson plasma resonance in Bi2Sr2CaCu2Oy SO PHYSICAL REVIEW LETTERS LA English DT Article ID VORTEX STATE; SUPERCONDUCTORS AB Effects of columnar defects on the Josephson plasma resonance (JPR) were investigated in heavy-ion irradiated Bi2Sr2CaCu2Oy. A microwave magnetoabsorption peak caused by the JPR shifted to higher fields with increasing defect densities. The amount of the shift indicated that the interlayer coupling was enhanced even above the matching field of the columnar defects. Another absorption peak was found around the matching field, which we attribute to a novel JPR caused by the nonmonotonic field dependence of the interlayer critical current density. These results indicated that the feature of the vortex system was drastically altered even by small number of columnar defects. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Hanaguri, T (reprint author), UNIV TOKYO,DEPT BASIC SCI,MEGURO KU,3-8-1 KOMABA,TOKYO 153,JAPAN. RI Hanaguri, Tetsuo/I-6710-2012; Tsuchiya, Yoshishige/B-6127-2013 OI Hanaguri, Tetsuo/0000-0003-2896-0081; NR 14 TC 36 Z9 36 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 21 PY 1997 VL 78 IS 16 BP 3177 EP 3180 DI 10.1103/PhysRevLett.78.3177 PG 4 WC Physics, Multidisciplinary SC Physics GA WU621 UT WOS:A1997WU62100038 ER PT J AU Thompson, JR KrusinElbaum, L Civale, L Blatter, G Feild, C AF Thompson, JR KrusinElbaum, L Civale, L Blatter, G Feild, C TI Superfast vortex creep in YBa2Cu3O7-delta crystals with columnar defects: Evidence for variable-range vortex hopping SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; FLUX-CREEP; CORRELATED DISORDER; MAGNETIC-RELAXATION; BOSON LOCALIZATION; GLASS; IRRADIATION; DEPENDENCE; TRANSPORT; VORTICES AB We observe a large peak in the vortex creep rate of YBa2Cu3O7-delta crystals with columnar defects. The peak appears at the crossover from the regime where vortices are well localized on columnar pins to a regime where vortex-vortex interactions dominate, and it is most prominent (nearly 12%) at low fields, near T similar to 40 K. Near this crossover, the current dependent creep activation energy U(J) shows distinct and unusual behavior (''pinch''). On the high-J side of the pinch, the glassy exponent mu - 1/3 and large creep rate are characteristic of variable range vortex hopping. C1 UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. IBM CORP,RES,YORKTOWN HTS,NY 10598. COMIS NACL ENERGIA ATOM,CTR ATOM BARILOCHE,RA-8400 SAN CARLOS BARILO,RIO NEGRO,ARGENTINA. ETH HONGGERBERG,CH-8093 ZURICH,SWITZERLAND. RP Thompson, JR (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 25 TC 81 Z9 81 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 21 PY 1997 VL 78 IS 16 BP 3181 EP 3184 DI 10.1103/PhysRevLett.78.3181 PG 4 WC Physics, Multidisciplinary SC Physics GA WU621 UT WOS:A1997WU62100039 ER PT J AU Nguyen, QV Paul, PH AF Nguyen, QV Paul, PH TI KrF laser-induced photobleaching effects in O-2 planar laser-induced fluorescence signals: Experiment and model SO APPLIED OPTICS LA English DT Article ID EXCIMER LASERS; OH; EXCITATION; FLAMES; PULSE AB KrF excimer lasers are often employed as high-power excitation sources in planar laser-induced fluorescence (PLIF) imaging experiments ta measure the distributions of O-2, OH, and H2O-all important species in combustion phenomena. However, due to the predissociative nature of these molecules, the high laser pumping rates typically required in such PLIF experiments may significantly deplete the ground-state population. The proper interpretation of the ground-state number density and/or the temperature from the fluorescence signals then requires the inclusion of photobleaching effects. We compare the results of a five-level rate-equation model incorporating photobleaching effects to the time-resolved PLIF signals from O-2 as obtained in the products of a fuel-lean CH4 air flame. The results indicate that the fluorescence signals in a typical predissociated PLIF imaging experiment are subject to significant amounts of photobleaching. In an effort to provide a convenient way to account for photobleaching, a simple three-level model is developed This model provides an analytic solution that describes satisfactorily the time-integrated fluorescence signal when compared with both the five-level model and the measurements. The results also indicate that at the low laser irradiances required to minimize the effects of photobleaching, the correspondingly low fluorescence signal levels make the acquisition of single-shot PLIF images a challenge to currently available camera systems. (C) 1997 Optical Society of America. RP Nguyen, QV (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 22 TC 7 Z9 8 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD APR 20 PY 1997 VL 36 IS 12 BP 2675 EP 2683 DI 10.1364/AO.36.002675 PG 9 WC Optics SC Optics GA WU839 UT WOS:A1997WU83900035 PM 18253258 ER PT J AU Olive, KA Schramm, DN Scully, ST Truran, JW AF Olive, KA Schramm, DN Scully, ST Truran, JW TI Low-mass stars and the He-3 problem SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy, abundances; ISM, abundances; nuclear reactions, nucleosynthesis, abundances; stars, interiors ID LOCAL INTERSTELLAR-MEDIUM; BIG-BANG NUCLEOSYNTHESIS; CHEMICAL EVOLUTION; DEUTERIUM ABUNDANCE; GIANT BRANCH; HALO-STARS; SUPERNOVAE; C-12/C-13; GALAXIES; CAPELLA AB Standard chemical evolution models predict an overabundance of He-3 from low-mass stars (in the range of 1-3 M.) with respect to the measured solar and present-day abundances and hence indicate a possible problem with the yields of He-3 in these stars. Because 3He is one of the nuclei produced in big bang nucleosynthesis (BBN), it is noted that Galactic and stellar evolution uncertainties necessarily relax constraints based on He-3. We incorporate into chemical evolution models that include outflow the new yields for He-3 of Boothroyd & Malaney (1995), which predict that low-mass stars are net destroyers of He-3. Since these yields do not account for the high He-3/H ratio observed in some planetary nebulae, we also consider the possibility that some fraction of stars in the 1-3 M. range do not destroy their He-3 in their post-main-sequence phase. We also consider the possibility that the gas expelled by stars in these mass ranges does not mix with the ISM instantaneously thus delaying the He-3 produced in these stars, according to standard yields, from reaching the ISM. In general, we find that the Galactic D and He-3 abundances can be fitted regardless of whether the primordial D/H value is high (2 x 10(-4)) (2.5 x 10(-5)). C1 UNIV CHICAGO, ENRICO FERMI INST, DEPT ASTRON & ASTROPHYS, CHICAGO, IL 60637 USA. FERMILAB NATL ACCELERATOR LAB, NASA, FERMILAB ASTROPHYS CTR, BATAVIA, IL 60510 USA. RP Olive, KA (reprint author), UNIV MINNESOTA, SCH PHYS & ASTRON, MINNEAPOLIS, MN 55455 USA. NR 65 TC 26 Z9 26 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 APR 20 PY 1997 VL 479 IS 2 BP 752 EP 759 DI 10.1086/303932 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WU505 UT WOS:A1997WU50500022 ER PT J AU Liu, WH AF Liu, WH TI Molecules in Type Ia supernovae SO ASTROPHYSICAL JOURNAL LA English DT Article DE molecular processes; radiative transfer; supernovae, general ID CARBON-MONOXIDE; RADIATIVE ASSOCIATION; ENERGY DEPOSITION; SN-1987A; C+ AB Mechanisms for formation and destruction of molecules in Type Ia supernovae (SNe Ia) are explored and contrasted with those in Type II supernovae (SNe II). In the absence of grains, molecular formation in the highly ionized ejecta is initiated by radiative association and radiative attachment. The molecules are destroyed by charge transfer and by energetic electron impact. The molecular abundances are calculated for the elemental compositions given by SNe Ia models. SNe Ia are an unfavorable environment for molecular formation because of the low gas density and the high-ionization fraction in the ejecta, and the masses of the molecules formed in SNe Ia are many orders of magnitude lower than those in SNe II. It is concluded that molecular formation should have no significant effect on the physical properties of SNe Ia, which is in sharp contrast with the case of SNe II. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. RP Liu, WH (reprint author), OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831, USA. NR 17 TC 7 Z9 7 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1997 VL 479 IS 2 BP 907 EP 911 DI 10.1086/303927 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WU505 UT WOS:A1997WU50500036 ER PT J AU Becker, RH Gregg, MD Hook, IM McMahon, RG White, RL Helfand, DJ AF Becker, RH Gregg, MD Hook, IM McMahon, RG White, RL Helfand, DJ TI The first radio-loud broad absorption line QSO and evidence for a hidden population of quasars SO ASTROPHYSICAL JOURNAL LA English DT Article DE quasars, absorption lines; quasars, general ID HIGH-REDSHIFT QUASARS; STELLAR OBJECTS AB We have discovered two low-ionization broad absorption line (BAL) quasars in programs to obtain optical spectra for radio-selected quasar candidates from the VLA Faint Images of the Radio Sky at Twenty Centimeters (FIRST) Survey. Both belong to the extremely rare class of BAL QSOs that exhibit narrow absorption lines from metastable excited levels of Fe II and Fe III. Until now, there was just a single object in this class, 0059-2735. In addition, one of our new objects is the first known radio-loud BAL QSO. The properties of these three unusual objects suggest a trend of increasing radio luminosity with the amount of absorption to the quasar, and are perhaps transition objects between radio-loud and radio-quiet quasars. The two new objects are from a radio-selected sample comprising less than 200 quasars; one is heavily attenuated at optical wavelengths in the observed frame. These objects would be easily overlooked by most optical QSO searches; their abundance in the radio sample suggests that they may be representatives of a largely undetected component of the quasar population, perhaps as numerous as ordinary low-ionization BAL QSOs, which constitute 1%-2% of all QSOs. C1 LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, LIVERMORE, CA 94550 USA. UNIV CALIF DAVIS, DAVIS, CA 95616 USA. EUROPEAN SO OBSERV, D-85748 GARCHING, GERMANY. INST ASTRON, CAMBRIDGE CB3 0HA, ENGLAND. SPACE TELESCOPE SCI INST, BALTIMORE, MD 21218 USA. COLUMBIA UNIV, COLUMBIA ASTROPHYS LAB, NEW YORK, NY 10027 USA. OI McMahon, Richard/0000-0001-8447-8869 NR 22 TC 124 Z9 124 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 APR 20 PY 1997 VL 479 IS 2 BP L93 EP L96 DI 10.1086/310594 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WU506 UT WOS:A1997WU50600004 ER PT J AU Chang, HK Ho, C AF Chang, HK Ho, C TI RXTE observation of PSR B1951+32 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars, individual (PSR B1951+32) ID SUPERNOVA REMNANT CTB-80; RAY TIMING EXPLORER; X-RAY; PULSED EMISSION; UPPER LIMITS; PROSPECTS; SEARCHES AB We report results of Rossi X-Ray Timing Explorer (RXTE) observations of PSR B1951+/-32 using the proportional counter array (PCA) instrument for 19 ks during 1996 March 24. We applied the contemporaneous radio ephemeris and various statistical tests to search for evidence of pulsation. These analyses yield intriguing yet inconclusive evidence for the presence of the pulsation in the time series: the confidence level for the presence of pulsation is 94.5% in the 2.0-4.8 keV band and 97.6% in the 4.8-6.3 keV band based on the H-test. Under the premise of nondetection of pulsation, we derive estimated 2 sigma upper limits for the pulsed flux to be 3.3 x 10(-6) cm(-2) s(-1) keV(-1) in the 2.0-4.8 keV band, 2.7 x 10(-6) cm(-2) s(-1) keV(-1) in the 4.8-8.5 keV band, and 2.0 x 10(-6) cm(-2) s(-1) keV(-1) in the 8.5-13.0 keV band. These upper limits are consistent with the trend of spectral turnover from high-energy gamma-ray emission as suggested by the OSSE upper limit. Such turnover strongly suggests the outer magnetosphere as the emission site for pulsed gamma-rays. These RXTE upper limits for X-ray pulsation are, on the other hand, not consistent with the extrapolation of reported power-law spectra from the point source observed by ROSAT in the 0.1-2.4 keV band, assuming a constant pulse fraction: the pulsed soft X-ray emission detected by ROSAT must follow a much softer spectrum than that of the overall point source. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 22 TC 14 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD APR 20 PY 1997 VL 479 IS 2 BP L125 EP L127 DI 10.1086/310602 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA WU506 UT WOS:A1997WU50600012 ER PT J AU Amberger, HD Jank, S Reddmann, H Edelstein, NM AF Amberger, HD Jank, S Reddmann, H Edelstein, NM TI Electron structure of highly symmetric compounds of f-elements .28. Experimental determination and simulation of the crystal field splitting pattern of tris(bis(trimethylsilyl)amido)neodymium(III) SO MOLECULAR PHYSICS LA German DT Article ID ORGANOMETAL COMPLEXES; ABSORPTION-SPECTRUM; MOLECULAR-STRUCTURE; COORDINATION; ALKOXIDES; NEODYMIUM; LANTHANIDES; DIFFRACTION; LANTHANOIDS; REACTIVITY AB The sigma and pi absorption spectra of an oriented single crystal of Nd(btmsa)(3) were measured at room and low temperatures. From the spectra obtained a truncated crystal held (CF) splitting pattern is derived, and simulated by fitting the free parameters of an empirical Hamiltonian. For 84 assignments an RMS deviation of 35.2 cm(-1) is achieved. On the basis of the wavefunctions of the CF ground state obtained from these calculations the 5K EPR spectrum of dissolved Nd(btmsa)(3) could be explained. Making use of the calculated wavefunctions and eigenvalues the experimentally determined temperature dependence of mu(eff)(2) of powdered Nd(btmsa)(3) could be reproduced by adopting an orbital reduction factor k = 0.975. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP Amberger, HD (reprint author), UNIV HAMBURG,INST ANORGAN & ANGEW CHEM,MARTIN LUTHER KING PL 6,D-20146 HAMBURG,GERMANY. NR 50 TC 23 Z9 23 U1 2 U2 9 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD APR 20 PY 1997 VL 90 IS 6 BP 1013 EP 1026 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WW348 UT WOS:A1997WW34800016 ER PT J AU Willis, JO Ray, RD Bingert, JF Phillips, DS Beckman, RJ Smith, MG Sebring, RJ Smith, PA Bingham, BL Coulter, JY Peterson, DE AF Willis, JO Ray, RD Bingert, JF Phillips, DS Beckman, RJ Smith, MG Sebring, RJ Smith, PA Bingham, BL Coulter, JY Peterson, DE TI Processing factors for high critical current density in Bi-2223/Ag tapes SO PHYSICA C LA English DT Article DE Bi-2223/Ag tapes; critical current density; thermomechanical processing AB Ten factors relating to Bi-2223/Ag tape production and thermomechanical processing have been examined in a statistically designed study to determine optimal parameter values for high critical current density J(c) in rolled tapes. The study indicates that low fill factor, narrow tapes processed for long times yield the best J(c) values, and that strain rate, as was expected, is not a significant factor. The major microstructural conclusion is that macrocracking, even at the early stages of tape processing, should be avoided, as these cracks cannot easily be healed. (C) 1997 Elsevier Science B.V. RP Willis, JO (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,SUPERCONDUCT TECHNOL CTR,MS-K763,LOS ALAMOS,NM 87545, USA. NR 10 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD APR 20 PY 1997 VL 278 IS 1-2 BP 1 EP 10 DI 10.1016/S0921-4534(97)00109-3 PG 10 WC Physics, Applied SC Physics GA XB793 UT WOS:A1997XB79300001 ER PT J AU Hofmann, P Plummer, EW AF Hofmann, P Plummer, EW TI Lattice vibrations at the Be(10(1)over-bar0) surface SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 16th European Conference on Surface Science CY SEP 09-13, 1996 CL GENOA, ITALY SP European Phys Soc, Condensed Matter Div, Surface & Interface Sect, Int Union Vacuum Sci Technol & Applicat DE alkaline earth metals; electron energy loss spectroscopy; low index single crystal surfaces ID ELECTRONIC-STRUCTURE; BERYLLIUM; SPECTRUM AB We have measured the surface phonon dispersion of Be(<10(1)over bar 0>) by electron energy loss spectroscopy (EELS) and found three surface resonances at the surface Brillouin zone centre as well as two surface phonons at the (A) over bar and (R) over bar points. The experimental data do not agree with a calculation for the truncated bulk. In particular. the predicted loss associated with the Rayleigh wave at the zone boundaries is not observed. The character of the surface vibrations suggests that the bonding is more complicated than on Be(0001) where the qualitative features of the surface phonon dispersion can be described within a simple central force model. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Hofmann, P (reprint author), UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996, USA. RI Hofmann, Philip/B-5938-2008 OI Hofmann, Philip/0000-0002-7367-5821 NR 17 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 1997 VL 377 IS 1-3 BP 330 EP 334 DI 10.1016/S0039-6028(96)01387-8 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA WZ496 UT WOS:A1997WZ49600071 ER PT J AU Magni, E Somorjai, GA AF Magni, E Somorjai, GA TI Surface science study of model Ziegler-Natta catalysts SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 16th European Conference on Surface Science CY SEP 09-13, 1996 CL GENOA, ITALY SP European Phys Soc, Condensed Matter Div, Surface & Interface Sect, Int Union Vacuum Sci Technol & Applicat DE amorphous thin films; catalysis; chemical vapor deposition; surface chemical reaction; titanium(IV)chloride; X-ray photoelectron spectroscopy ID CHLORIDE THIN-FILMS; MAGNESIUM-CHLORIDE; TITANIUM CHLORIDE; GOLD AB The preparation and surface science study of model catalysts for the Ziegler-Natta polymerization are reported. Ultra-thin films of MgCl2 and TiCl4 have been prepared by gas phase deposition on polycrystalline Au foil in UHV conditions and are characterized by XPS. Titanium chloride films can be deposited on both MgCl2 films and clean An at 300 K in a background TiCl4 pressure of 1 x 10(-8)-5 x 10(-7) Torr, in the presence of an electron beam of 1 keV irradiating the substrate. The deposited titanium chloride consists of a TiCl2 multilayer film with one monolayer of TiCl4 chemisorbed at the surface. Upon exposure of AlEt3, the TiCl4 monolayer undergoes reduction and alkylation with the formation of TiCl2Et and TiClEtn species at the film surface, No evidence for TiCl3 formation is observed. These model systems are active catalysts for the Ziegler-Natta polymerization of both ethylene and propylene. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 6 TC 29 Z9 29 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD APR 20 PY 1997 VL 377 IS 1-3 BP 824 EP 827 DI 10.1016/S0039-6028(96)01512-9 PG 4 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA WZ496 UT WOS:A1997WZ49600168 ER PT J AU Yoshikawa, T Sanders, AR Esterling, LE Overhauser, J Garnes, JA Lennon, G Grewal, R DeteraWadleigh, SD AF Yoshikawa, T Sanders, AR Esterling, LE Overhauser, J Garnes, JA Lennon, G Grewal, R DeteraWadleigh, SD TI Isolation of chromosome 18-specific brain transcripts as positional candidates for bipolar disorder SO AMERICAN JOURNAL OF MEDICAL GENETICS LA English DT Article DE brain cDNA; cosmids; somatic cell hybrid; radiation hybrid; mapping; PCR ID CDNA LIBRARY; GENE; SEQUENCE; PROTEIN; HYBRIDIZATION; EXPRESSION; LINKAGE; MAP AB Several studies have proposed the existence of susceptibility loci for bipolar disorder on chromosome 18, To identify possible candidate genes for this disease, we isolated brain-expressed transcripts by direct cDNA selection on chromosome 18-specific biotinylated cosmid clones, Longer cognate cDNA clones of the selected cDNAs were isolated from a normalized infant brain cDNA library, Physical mapping by PCR on a panel of somatic cell hybrids was conducted by the use of primers derived from partial sequences on either the 5' or 3' ends of the clones, In our initial analysis, 48 cDNA clones were found to be chromosome 18-specific, mapping to different subchromosomal regions, Sequence redundancy among these clones yielded 30 unique transcripts, five of which were represented in previously known genes, Further sequencing of the remaining 25 unique cDNA clones confirmed the absence of significant homology to known genes, indicating that these transcripts represented novel genes, Mapping with the use of a radiation hybrid panel positioned the brain cDNAs to within approximate to 100 to 1100 kb from reference sequence tag sites (STSs) and assembled them into six high resolution linkage groups, The majority of the transcripts were found to cluster to discrete locations on 18p and 18q, previously hypothesized as susceptibility regions for bipolar disorder, identifying them as positional candidate genes. (C) 1997 Wiley-Liss, Inc. C1 NIMH,UNIT GENE MAPPING & EXPRESS,CLIN NEUROGENET BRANCH,NIH,BETHESDA,MD 20892. NIDOCD,GENET MOL LAB,NIH,BETHESDA,MD. THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT BIOCHEM & MOL BIOL & MED GENET,PHILADELPHIA,PA 19107. LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,LIVERMORE,CA. UNIV SO CALIF,SCH MED,DEPT NEUROL,LOS ANGELES,CA 90033. FU NIA NIH HHS [P05-AG05142, K12 AG00521] NR 32 TC 15 Z9 15 U1 0 U2 1 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0148-7299 J9 AM J MED GENET JI Am. J. Med. Genet. PD APR 18 PY 1997 VL 74 IS 2 BP 140 EP 149 DI 10.1002/(SICI)1096-8628(19970418)74:2<140::AID-AJMG5>3.0.CO;2-Y PG 10 WC Genetics & Heredity SC Genetics & Heredity GA WV797 UT WOS:A1997WV79700005 PM 9129712 ER PT J AU Gifford, AN Samiian, L Gatley, SJ Ashby, CR AF Gifford, AN Samiian, L Gatley, SJ Ashby, CR TI Examination of the effect of the cannabinoid receptor agonist, CP 55,940, on electrically evoked transmitter release from rat brain slices SO EUROPEAN JOURNAL OF PHARMACOLOGY LA English DT Article DE cannabinoid receptor; CP 55,940; SR 141716A; brain slice; acetylcholine ID LOCALIZATION; POTENT; ANTAGONIST; SR141716A; CHANNELS; ANALOGS; MEMORY; CELLS AB In the present study we examined the effect of the cannabinoid receptor agonist, {[la,2-(R)-5-(1,1-dimethylheptyl)-2-[5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]-phenol; CP 55,940} on [C-14]acetylcholine and [H-3]norepinephrine release from hippocampal slices and on [C-14]acetylcholine release from striatal slices. CP 55,940 potently inhibited electrically evoked [C-14]acetylcholine release from hippocampal slices, with an EC50 of 0.02 mu M and a maximal inhibition of 61% at 1 mu M The inhibition of acetylcholine release by CP 55.940 was partially antagonized (60%) by the cannabinoid receptor antagonist, {[N-piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1-H-pyrazole-3-carboxamide hydrochloride; SR 141716A}. Alone, SR 141716A significantly enhanced stimulated [C-14]acetylcholine release. In contrast to the effects of CP 55,940 on [C-14]acetylcholine release, electrically evoked [H-3]norepinephrine release from hippocampal slices and [C-14]acetylcholine release from striatal slices were both unaffected by this compound. Similarly, hippocampal [H-3]norepinephrine release and striatal [C-14]acetylcholine release were not affected by SR 141716A. In conclusion, the results of this study extend our previous data indicating that cannabinoid receptors modulate acetylcholine release in the hippocampus. The effects of cannabinoid receptor activation on [H-3]acetylcholine release in the hippocampus does not appear to extend to [H-3]norepinephrine release from this region or to acetylcholine release from the striatum. (C) 1997 Elsevier Science B.V. C1 ST JOHNS UNIV,DEPT PHARMACEUT SCI,JAMAICA,NY 11439. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. FU NIMH NIH HHS [MH 52155] NR 33 TC 65 Z9 66 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-2999 J9 EUR J PHARMACOL JI Eur. J. Pharmacol. PD APR 18 PY 1997 VL 324 IS 2-3 BP 187 EP 192 DI 10.1016/S0014-2999(97)00082-4 PG 6 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA WV747 UT WOS:A1997WV74700008 PM 9145770 ER PT J AU Zhang, NY Yeung, ES AF Zhang, NY Yeung, ES TI Simultaneous separation and genetic typing of four short tandem repeat loci by capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article; Proceedings Paper CT 4th International Symposium on Capillary Electrophoresis CY AUG 21-23, 1996 CL YORK, ENGLAND SP Chromatog Soc, Brit Electrophoresis Soc, Univ York DE DNA ID LASER-INDUCED FLUORESCENCE; GEL-ELECTROPHORESIS; HIGH-SPEED; POPULATION; IDENTIFICATION AB Genetic typing based on the four short tandem repeat (STR) loci vWF, THO1, TPOX and CSF1PO by capillary electrophoresis and laser-induced fluorescence detection has been demonstrated. It was necessary to separate these alleles in single-stranded form and to prevent rehybridization and eliminate secondary structures. Separation under both denaturing and non-denaturing conditions is discussed. Poly(ethylene oxide) (PEO) (1.6% 8 000 000 M-r) and PEO (1.5% 600 000 M-r) were dissolved in 1XTBE (0.54 g Tris, 0.275 g boric acid and 0.100 mmol disodium EDTA, diluted to 50 ml with deionized water), 3.5 M urea buffer was the separation matrix used for denaturing condition. A matrix composed of 1.9% 8 000 000 M-r PEO and 1.8% 600 000 M-r PEO in 1XTBE was used for the non-denaturing condition. Elevated temperature was required when the separation was performed without urea. Single-base resolution was obtained in both cases. Non-denaturing electrophoresis results in faster separations. Future adaptation to multiple-capillary array systems should allow fast genotyping of large numbers of samples simultaneously. C1 IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV,US DEPT ENERGY,AMES LAB,AMES,IA 50011. NR 19 TC 25 Z9 27 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD APR 18 PY 1997 VL 768 IS 1 BP 135 EP 141 DI 10.1016/S0021-9673(96)00991-0 PG 7 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA WY411 UT WOS:A1997WY41100017 ER PT J AU Huynen, M Gutell, R Konings, D AF Huynen, M Gutell, R Konings, D TI Assessing the reliability of RNA folding using statistical mechanics SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE RNA secondary structure; RNA folding; base-pairing probability distribution; ribosomal RNA; thermophiles ID RIBOSOMAL-RNA; SECONDARY STRUCTURE; SP-NOV; SEQUENCES; 16S; PREDICTIONS; PARAMETERS; BACTERIA AB We have analyzed the base-pairing probability distributions of 16 S and 16 S-Like, and 23 S and 23 S-like ribosomal RNAs of Archaea, Bacteria, chloroplasts, mitochondria and Eukarya, as predicted by the partition function approach for RNA folding introduced by McCaskill. A quantitative analysis of the reliability of RNA folding is done by comparing the base-pairing probability distributions with the structures predicted by comparative sequence analysis (comparative structures). We distinguish two factors that show a relationship to the reliability of RNA minimum free energy structure. The first factor is the dominance of one particular base-pair or the absence of base-pairing for a given base within the base-pairing probability distribution (BPPD). We characterize the BPPD per base, including the probability of not base-pairing, by its Shannon entropy (S). The S value indicates the uncertainty about the base-pairing of a base: low S values result from BPPDs that are strongly dominated by a single base-pair or by the absence of base-pairing. We show that bases with low S values have a relatively high probability that their minimum free energy (MFE) structure corresponds to the comparative structure. The BPPDs of prokaryotes that live at high temperatures (thermophilic Archaea and Bacteria) have, calculated at 37 degrees C, lower S values than the BPPDs of prokaryotes that live at lower temperatures (mesophilic and psychrophilic Archaea and Bacteria). This reflects an adaptation of the ribosomal RNAs to the environmental temperature. A second factor that is important to consider with regard to the reliability of MFE structure folding is a variable degree of applicability of the thermodynamic model. of RNA folding for different groups of RNAs. Here we show that among the bases that show low S values, the Archaea and Bacteria have similar, high probabilities (0.96 and 0.94 in 16 S and 0.93 and 0.91 in 23 S, respectively) that the MFE structure corresponds to the comparative structure. These probabilities are lower in the chloroplasts (16 S 0.91, 23 S 0.79), mitochondria (16 S-like 0.89, 23 S-like 0.69) and Eukarya (18 S 0.81, 28 S 0.86). (C) 1997 Academic Press Limited. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. SANTA FE INST,SANTA FE,NM 87501. UNIV COLORADO,BOULDER,CO 80309. FU NIGMS NIH HHS [GM-48207, R01 GM048207] NR 29 TC 55 Z9 55 U1 1 U2 4 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD APR 18 PY 1997 VL 267 IS 5 BP 1104 EP 1112 DI 10.1006/jmbi.1997.0889 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA WU942 UT WOS:A1997WU94200005 PM 9150399 ER PT J AU Zhang, ZY Lagally, MG AF Zhang, ZY Lagally, MG TI Atomistic processes in the early stages of thin-film growth SO SCIENCE LA English DT Review ID SCANNING-TUNNELING-MICROSCOPY; MOLECULAR-BEAM EPITAXY; BY-LAYER GROWTH; DIFFUSION-LIMITED AGGREGATION; ENERGY-ELECTRON DIFFRACTION; SURFACE SELF-DIFFUSION; METAL-SURFACES; HOMOEPITAXIAL GROWTH; ISLAND MORPHOLOGY; CLUSTER MOBILITY AB Growth of thin films from atoms deposited from the gas phase is intrinsically a non-equilibrium phenomenon governed by a competition between kinetics and thermodynamics. Precise control of the growth and thus of the properties of deposited films becomes possible only after an understanding of this competition is achieved. Here, the atomic nature of the most important kinetic mechanisms of film growth is explored. These mechanisms include adatom diffusion on terraces, along steps, and around island corners; nucleation and dynamics of the stable nucleus; atom attachment to and detachment from terraces and islands; and interlayer mass transport. Ways to manipulate the growth kinetics in order to select a desired growth mode are briefly addressed. C1 UNIV WISCONSIN,DEPT MAT SCI & ENGN,MADISON,WI 53706. UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. RP Zhang, ZY (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 111 TC 640 Z9 671 U1 33 U2 236 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 18 PY 1997 VL 276 IS 5311 BP 377 EP 383 DI 10.1126/science.276.5311.377 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WU477 UT WOS:A1997WU47700029 ER PT J AU Chen, CC Herhold, AB Johnson, CS Alivisatos, AP AF Chen, CC Herhold, AB Johnson, CS Alivisatos, AP TI Size dependence of structural metastability in semiconductor nanocrystals SO SCIENCE LA English DT Article ID HIGH-PRESSURE PHASE; ROCK-SALT PHASE; CDSE NANOCRYSTALS; TRANSITION; WURTZITE; TRANSFORMATION; NITRIDE; SURFACE; GAP AB The kinetics of a first-order, solid-solid phase transition were investigated in the prototypical nanocrystal system CdSe as a function of crystallite size. In contrast to extended solids, nanocrystals convert from one structure to another by single nucleation events, and the transformations obey simple unimolecular kinetics. Barrier heights were observed to increase with increasing nanocrystal size, although they also depend on the nature of the nanocrystal surface. These results are analogous to magnetic phase transitions in nanocrystals and suggest general rules that may be of use in the discovery of new metastable phases. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RI Chen, Chia-Chun/F-7939-2012; Alivisatos , Paul /N-8863-2015 OI Alivisatos , Paul /0000-0001-6895-9048 NR 34 TC 420 Z9 422 U1 4 U2 80 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD APR 18 PY 1997 VL 276 IS 5311 BP 398 EP 401 DI 10.1126/science.276.5311.398 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WU477 UT WOS:A1997WU47700034 ER PT J AU Vinchurkar, MS Rao, BSM Mohan, H Mittal, JP Schmidt, KH Jonah, CD AF Vinchurkar, MS Rao, BSM Mohan, H Mittal, JP Schmidt, KH Jonah, CD TI Absorption spectra of isomeric OH adducts of 1,3,7-trimethylxanthine SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID UNIMOLECULAR TRANSFORMATION REACTIONS; FREE-RADICAL ADDUCTS; PULSE-RADIOLYSIS; AQUEOUS-SOLUTION; HYDRATED ELECTRONS; PURINE-BASES; PATTERN; NUCLEOSIDES; NUCLEOTIDES; DEHYDRATION AB The reactions of OH., O.-, and SO4.- with 1,3,7-trimethylxanthine (caffeine) were studied by pulse radiolysis with optical and conductance detection techniques. The absorption spectra of transients formed in OH. reaction in neutral solutions exhibited peaks at 310 and 335 nm, as well as a broad absorption maximum at 500 nm, which decayed by first-order kinetics. The rate (k = (4.0 +/- 0.5) x 10(4) s(-1)) of this decay is independent of pH in the range 4-9 and is in agreement with that determined from the conductance detection (k = 4 x 10(4) s(-1)). The spectrum in acidic solutions has only a broad peak around 330 nm with no absorption in the higher wavelength region. The intermediates formed in reaction of O.- absorb around 310 and at 500 nm, and the first-order decay at the latter wavelength was not seen. The OH radical adds to C-4 (X-4OH(.)) and C-8 (X-8OH(.)) positions of caffeine in the ratio 1:2 as determined from the redox titration and conductivity measurements. H abstraction from the methyl group is an additional reaction channel in O.- reaction. Dehydroxylation of the X-4OH(.) adduct occurs, whereas the X-8OH(.) adduct does not undergo ring opening. The rate constant for addition of O-2 to X-4OH(.) is estimated to be similar to 1 x 10(9) M-1 s(-1), whereas it is unreactive toward X-8OH(.). The spectrum obtained for OH. reaction in oxygenated solutions is similar to that observed in SO4.- reaction in basic solutions. The radical cation of caffeine formed from its reaction with SO4.- (lambda(max) = 320-340 nm) is hydrolyzed in basic solutions to yield the X-8OH(.) adduct. The molar absorptivities of the X-8OH(.) and the X-4OH(.) adducts at 300 and 335 nm are 6500 and 5300 M-1 cm(-1), respectively. The yield of 1,3,7-trimethyluric acid in OH. reaction in the absence of O-2 (28%) is reduced by more than 50% in its presence. The differences in the mechanism of OH. reaction with caffeine and its isomer 1,3,9-trimethylxanthine (isocaffeine) are discussed. C1 UNIV PUNE,DEPT CHEM,PUNE 411007,MAHARASHTRA,INDIA. BHABHA ATOM RES CTR,DIV CHEM,BOMBAY 400085,MAHARASHTRA,INDIA. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 34 TC 10 Z9 10 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD APR 17 PY 1997 VL 101 IS 16 BP 2953 EP 2959 DI 10.1021/jp963272q PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WU629 UT WOS:A1997WU62900006 ER PT J AU Adant, C Bredas, JL Dupuis, M AF Adant, C Bredas, JL Dupuis, M TI An ab initio and semiempirical study of the first- and third-order polarizabilities in benzene and thiophene derivatives: Electron correlation effects SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID NONLINEAR-OPTICAL-PROPERTIES; CONJUGATED ORGANIC-MOLECULES; BOND-LENGTH ALTERNATION; POLYPARAPHENYLENE VINYLENE; 3RD-HARMONIC GENERATION; DIPOLE POLARIZABILITIES; ABINITIO CALCULATIONS; FREQUENCY-DEPENDENCE; BASIS-SET; HYPERPOLARIZABILITIES AB The static first- and third-order polarizabilities of several benzene and thiophene derivatives are evaluated at the ab initio level via an efficacious general finite field approach. The impact of electron correlation is explored by calculating the molecular polarizabilities at the Moller-Plesset second-order perturbation (MP2) theory level using an extended basis set. Further, we examine the influence of molecular architecture on the nonlinear optical response, in particular the switch from an arylethenyl type of structure to a quinoid structure. Finally, we apply the correction vector method combined with the intermediate neglect of differential overlap-single and double excitation configuration interaction (INDO-SDCI) technique to evaluate the optical nonlinearities at the semiempirical level. The reliability of this procedure is established by comparison with the corresponding high-level ab initio polarizability values. The results clearly show the sensitive dependence of the nonlinear optical properties on electron correlation effects that are found to quantitatively and qualitatively affect the third-order polarizability values. C1 UNIV MONS, CTR RECH ELECT & PHOTON MOL, SERV CHIM MAT NOUVEAUX, B-7000 MONS, BELGIUM. PACIFIC NW LAB, EMLS K190, RICHLAND, WA 99352 USA. RI Bredas, Jean-Luc/A-3431-2008 OI Bredas, Jean-Luc/0000-0001-7278-4471 NR 60 TC 30 Z9 30 U1 0 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 APR 17 PY 1997 VL 101 IS 16 BP 3025 EP 3031 DI 10.1021/jp9630129 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA WU629 UT WOS:A1997WU62900016 ER PT J AU Hummer, G Pratt, LR Garcia, AE Berne, BJ Rick, SW AF Hummer, G Pratt, LR Garcia, AE Berne, BJ Rick, SW TI Electrostatic potentials and free energies of solvation of polar and charged molecules SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID PERIODIC BOUNDARY-CONDITIONS; WATER; SIMULATIONS; HYDRATION; DYNAMICS AB Theories of solvation free energies often involve electrostatic potentials at the position of a solute charge. Simulation calculations that apply cutoffs and periodic boundary conditions based on molecular centers result in center-dependent contributions to electrostatic energies due to a systematic sorting of charges in radial shells. This sorting of charges induces a surface-charge density at the cutoff sphere or simulation-box boundary that depends on the choice of molecular centers. We identify a simple solution that gives correct, center-independent results, namely the radial integration of charge densities. Our conclusions are illustrated for a Lennard-Jones solute in water. The present results can affect the parametrization of force fields. C1 COLUMBIA UNIV,DEPT CHEM,NEW YORK,NY 10027. COLUMBIA UNIV,CTR BIOMOL SIMULAT,NEW YORK,NY 10027. NCI,FREDERICK CANC RES & DEV CTR,FREDERICK,MD 21702. RP Hummer, G (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,MS K710,LOS ALAMOS,NM 87545, USA. RI Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 15 TC 91 Z9 93 U1 0 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 17 PY 1997 VL 101 IS 16 BP 3017 EP 3020 DI 10.1021/jp964037a PG 4 WC Chemistry, Physical SC Chemistry GA WU630 UT WOS:A1997WU63000002 ER PT J AU Majewski, J Kuhl, TL Gerstenberg, MC Israelachvili, JN Smith, GS AF Majewski, J Kuhl, TL Gerstenberg, MC Israelachvili, JN Smith, GS TI Structure of phospholipid monolayers containing poly(ethylene glycol) lipids at the air-water interface SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID X-RAY REFLECTIVITY; STERICALLY STABILIZED LIPOSOMES; GRAFTED POLYMER BRUSH; NEUTRON REFLECTIVITY; INTERACTION FORCES; SOLVENT QUALITY; SURFACES; SURFACTANTS; ADSORPTION; MOLECULES AB The density distribution of a lipid monolayer al the air-water interface mixed with varying amounts of lipid with poly(ethylene glycol) polymer headgroups (polymer-lipid or PEG-lipid) was measured using neutron reflectometry. The structure of the monolayer at the interface was greatly perturbed by the presence of the bulky polymer-lipid headgroups resulting in a large increase in the thickness of the headgroup region normal to the interface and a systematic roughening of the interface with increasing polymer-lipid content. These results show how bulky hydrophilic moieties cause significant deformations and out-of-plane protrusions of phospholipid monolayers and presumably bilayers, vesicles, and biological membranes. In terms of polymer physics, very short polymer chains tethered to the air-water interface follow scaling behavior with a mushroom to brush transition with increasing polymer grafting density. C1 LOS ALAMOS NATL LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545. UNIV CALIF SANTA BARBARA,DEPT CHEM ENGN,SANTA BARBARA,CA 93106. RISO NATL LAB,DEPT SOLID STATE PHYS,DK-4000 ROSKILDE,DENMARK. RI Lujan Center, LANL/G-4896-2012 NR 41 TC 88 Z9 89 U1 2 U2 23 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 17 PY 1997 VL 101 IS 16 BP 3122 EP 3129 DI 10.1021/jp962623y PG 8 WC Chemistry, Physical SC Chemistry GA WU630 UT WOS:A1997WU63000016 ER PT J AU Rodriguez, JA Kuhn, M AF Rodriguez, JA Kuhn, M TI Adsorption of sulfur on Ag/Al2O3 and Zn/Al2O3 surfaces: Thermal desorption, photoemission, and molecular orbital studies SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID EFFECTIVE CORE POTENTIALS; PHOTOELECTRON-SPECTROSCOPY; PROMOTED SULFIDATION; CHEMICAL-PROPERTIES; MODEL CATALYSTS; ALPHA-ALUMINA; SILVER; ABINITIO; AG(110); CHEMISORPTION AB The interaction of S-2 with Ag/Al2O3 and Zn/Al2O3 surfaces has been investigated using thermal desorption mass spectroscopy, core- and valence-level photoemission, and ab initio self-consistent-field calculations. The sticking coefficient of S-2 On clean alumina is small (<0.1) at temperatures between 300 and 700 K. In the S-2/Al2O3 system, there is an energy mismatch between the orbitals of the molecule and the bands of the oxide, and the reactivity of S-2 On pure alumina is very low. The adsorption of sulfur on Ag/Al2O3 and Zn/Al2O3 surfaces induces strong perturbations in the electronic properties of the admetals and oxide support. In the Ag/Al2O3 and Zn/Al2O3 systems, the supported metal clusters (or particles) provide a large number of electronic states that are very efficient at donating charge into the S-2(2 pi g) orbitals, inducing in this way the breaking of the S-S bond and the formation of admetal sulfides (AgSx and ZnSy). The larger the electron transfer from the supported metal into the S-2(2 pi g) orbitals, the bigger the adsorption energy of the molecule and the easier the cleavage of the S-S bond. The AgS, and ZnS, species decompose at temperatures between 750 and 900 K following two different reaction pathways: AgSx,solid --> S-2,S-gas + Ag-solid and ZnSy,solid --> S-2,S-gas + Zn-gas. RP Rodriguez, JA (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 83 TC 12 Z9 12 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 17 PY 1997 VL 101 IS 16 BP 3187 EP 3195 DI 10.1021/jp964022c PG 9 WC Chemistry, Physical SC Chemistry GA WU630 UT WOS:A1997WU63000025 ER PT J AU DePaul, SM ERnst, M Shore, JS Stebbins, JF Pines, A AF DePaul, SM ERnst, M Shore, JS Stebbins, JF Pines, A TI Cross-polarization from quadrupolar nuclei to silicon using low-radio-frequency amplitudes during magic-angle spinning SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PROTON-ENHANCED NMR; SOLID-STATE NMR; MAGNETIC-RESONANCE; CORRELATION SPECTROSCOPY; COHERENCE TRANSFER; ROTATING SOLIDS; LOW ALBITE; MAS; SILICATES; LOCKING AB The dynamics of cross-polarization from the central transition of a quadrupolar nucleus (Al-27 or Na-23) to a spin-1/2 nucleus (Si-29) during magic-angle spinning and using low-radio-frequency Geld strengths are analyzed for the mineral low albite. Under these conditions additional complications in the spin-lock behavior of the quadrupolar nucleus and in the cross-polarization process were found experimentally and are examined in detail. A step-by-step procedure for optimizing cross-polarization from the central transition of a quadrupolar nucleus to a spin-1/2 nucleus is described. Significant enhancement of Si-29 NMR sensitivity and several applications are demonstrated. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. STANFORD UNIV,DEPT GEOL,STANFORD,CA 94305. RI Ernst, Matthias/A-6732-2010 OI Ernst, Matthias/0000-0002-9538-6086 NR 50 TC 55 Z9 55 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD APR 17 PY 1997 VL 101 IS 16 BP 3240 EP 3249 DI 10.1021/jp9623711 PG 10 WC Chemistry, Physical SC Chemistry GA WU630 UT WOS:A1997WU63000031 ER PT J AU Andriulli, JB AF Andriulli, JB TI An easy way to measure mass moments of inertia SO MACHINE DESIGN LA English DT Editorial Material RP Andriulli, JB (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENTON PUBL INC PI CLEVELAND PA 1100 SUPERIOR AVE, CLEVELAND, OH 44114 SN 0024-9114 J9 MACH DES JI Mach. Des. PD APR 17 PY 1997 VL 69 IS 8 BP 90 EP & PG 3 WC Engineering, Mechanical SC Engineering GA WV194 UT WOS:A1997WV19400044 ER PT J AU Goity, JL Zhang, LZ AF Goity, JL Zhang, LZ TI Complete leading order analysis in chiral perturbation theory of the decays K-L->gamma gamma and K-L->l(+)l(-)gamma SO PHYSICS LETTERS B LA English DT Article ID KAON DECAYS; FORM-FACTOR; MESONS; KL->E+E-GAMMA; MASS AB The decays K-L --> gamma gamma and K-L --> l(+)l(-)gamma are studied at the leading order p(6) in chiral perturbation theory. One-loop contributions stemming from the odd intrinsic parity \Delta S\ = 1 effective Lagrangian of order p(4) are included and shown to be of possible relevance. They affect the decay K-L --> gamma gamma adding to the usual pole terms a piece free of counterterm uncertainties. In the case of the K-L --> l(+)l(-)gamma decays the dependence of the form factor on the dilepton invariant mass requires a counterterm. The form factor may receive a sizeable contribution from chiral logarithms. Including considerations from the K-L --> pi(+)pi(-)gamma direct emission amplitude, we obtain two consistent scenarios. In one scenario the long distance contributions from the one-loop terms are important, while in the other they are marginal. In both cases the counterterm is shown to be significant. (C) 1997 Elsevier Science B.V. C1 JEFFERSON LAB,NEWPORT NEWS,VA 23606. RP Goity, JL (reprint author), HAMPTON UNIV,DEPT PHYS,HAMPTON,VA 23668, USA. NR 17 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 17 PY 1997 VL 398 IS 3-4 BP 387 EP 392 DI 10.1016/S0370-2693(97)00246-3 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV258 UT WOS:A1997WV25800026 ER PT J AU Afanasev, A Carlson, CE Wahlquist, C AF Afanasev, A Carlson, CE Wahlquist, C TI Probing polarized parton distributions with meson photoproduction SO PHYSICS LETTERS B LA English DT Article ID SPIN STRUCTURE-FUNCTION; PION FORM-FACTOR; DEEP-INELASTIC SCATTERING; SEMIEXCLUSIVE PRODUCTION; PRECISION-MEASUREMENT; PROTON; QCD; HADRONS; TARGET; SEA AB Polarization asymmetries in photoproduction of high transverse momentum mesons are a flavor sensitive way to measure the polarized quark distributions. We calculate the expected asymmetries in several models, and find that the asymmetries are significant and also significantly different from model to model, Suitable data may come as a by-product of deep inelastic experiments to measure g(1) or from dedicated experiments. (C) 1997 Elsevier Science B.V. C1 HAMPTON UNIV,DEPT PHYS,HAMPTON,VA 23668. COLL WILLIAM & MARY,DEPT PHYS,WILLIAMSBURG,VA 23187. RP Afanasev, A (reprint author), THOMAS JEFFERSON NATL ACCELERATOR FACIL,12000 JEFFERSON AVE,NEWPORT NEWS,VA 23606, USA. OI Afanasev, Andrei/0000-0003-0679-3307 NR 31 TC 25 Z9 25 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD APR 17 PY 1997 VL 398 IS 3-4 BP 393 EP 399 DI 10.1016/S0370-2693(97)00219-0 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV258 UT WOS:A1997WV25800027 ER PT J AU Brisard, GM Zenati, E Gasteiger, HA Markovic, NM Ross, PN AF Brisard, GM Zenati, E Gasteiger, HA Markovic, NM Ross, PN TI Underpotential deposition of lead on Cu(100) in the presence of chloride: Ex-situ low-energy electron diffraction, auger electron spectroscopy, and electrochemical studies SO LANGMUIR LA English DT Article ID 2-DIMENSIONAL PHASE-TRANSITIONS; SINGLE-CRYSTAL SURFACES; COPPER; CHEMISTRY; CU(111); GOLD; ELECTRODEPOSITION; ADSORPTION; SUBSTRATE; INTERFACE AB Electrochemical and ultrahigh vacuum measurements are presented for the underpotential deposition (UPD) of Pb on Cu(100) in the presence of chloride ions. The chemistry is very similar to that for the (111) surface studied previously by the same methods. UPD Pb forms a compact layer of fully discharged atoms having essentially the same density as that in the (100) plane of bulk Pb. The deposition appears to occur via a single process, the nucleation and growth of Pb islands, but other types of growth modes cannot be excluded. The presence of chloride ion in the electrolyte enhances the kinetics of Pb deposition in both the underpotential and overpotential regions and results in a approximate to 0.1 V negative shift in the mean potential for UPD versus that in chloride-free perchloric acid. This shift can be accounted for in a simple thermodynamic model for the total Cu/Pb/Cl system. The only real difference in Pb UPD on the two different Cu crystal faces was the absence of an ordered structure for the compact layer on Cu(100), versus the ordered structure observed on Cu(111). This difference appears to be related to a lower mobility of Pb adatoms due to the greater atomic corrugation of the (100) surface. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RP UNIV SHERBROOKE, DEPT CHIM, SHERBROOKE, PQ J1K 2R1, CANADA. NR 32 TC 28 Z9 28 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 16 PY 1997 VL 13 IS 8 BP 2390 EP 2397 DI 10.1021/la960999x PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA WU674 UT WOS:A1997WU67400033 ER PT J AU George, EP Liu, CT Pope, DP AF George, EP Liu, CT Pope, DP TI Fracture in Ni3Al: Environmental and dopant effects SO PHYSICA STATUS SOLIDI A-APPLIED RESEARCH LA English DT Article; Proceedings Paper CT 3rd International Conference on Ultra-High-Purity Base Metals (UHPM-96) CY SEP 29-OCT 02, 1996 CL STUTTGART, GERMANY ID ROOM-TEMPERATURE DUCTILITY; GRAIN-BOUNDARY FRACTURE; BORON-DOPED NI3AL; POLYCRYSTALLINE NI3AL; INTRINSIC DUCTILITY; MAJOR CAUSE; EMBRITTLEMENT; COMPOUND; SEGREGATION; STRENGTH AB Environmental and dopant effects are by far the most significant of the extrinsic factors that influence intergranular fracture in Ni3Al. Environmental embrittlement is a result principally of the atomic hydrogen generated in the reaction with water vapor in ordinary ambient air. Dry hydrogen gas, in contrast, is relatively benign, presumably because it does not dissociate readily into atomic H on the Ni3Al surfaces. The effect of boron doping is primarily to suppress moisture-induced embrittlement, and secondarily to improve grain-boundary cohesion. In gaseous hydrogen atmospheres, boron has a third (unexpected) embrittling effect, which produces brittle intergranular fracture in otherwise ductile Ni3Al, presumably by enhancing the dissociation of H-2 on the grain boundaries. These and other extrinsic factors that affect the ductility and fracture behavior of Ni3Al are reviewed. C1 UNIV PENN,DEPT MAT SCI & ENGN,PHILADELPHIA,PA 19104. RP George, EP (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,1 BETHEL VALLEY RD,OAK RIDGE,TN 37831, USA. RI George, Easo/L-5434-2014; OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 37 TC 9 Z9 11 U1 0 U2 4 PU AKADEMIE VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0031-8965 J9 PHYS STATUS SOLIDI A JI Phys. Status Solidi A-Appl. Res. PD APR 16 PY 1997 VL 160 IS 2 BP 517 EP 529 DI 10.1002/1521-396X(199704)160:2<517::AID-PSSA517>3.0.CO;2-S PG 13 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA WY762 UT WOS:A1997WY76200024 ER PT J AU Schaefer, HE Damson, B Weller, M Arzt, E George, EP AF Schaefer, HE Damson, B Weller, M Arzt, E George, EP TI Thermal vacancies and high-temperature mechanical properties of FeAl SO PHYSICA STATUS SOLIDI A-APPLIED RESEARCH LA English DT Article; Proceedings Paper CT 3rd International Conference on Ultra-High-Purity Base Metals (UHPM-96) CY SEP 29-OCT 02, 1996 CL STUTTGART, GERMANY ID DEFECTS AB The formation and the kinetics of migration of thermal vacancies in Fe61Al39 have been studied by positron lifetime spectroscopy. From the temperature variation of the equilibrium vacancy concentration an effective vacancy formation enthalpy of H-V(F)=0.98 eV has been determined. From the equilibrium of the thermal vacancy concentration after temperature changes the vacancy migration enthalpy (H-V(M)=1.7 eV) could be derived. As observed recently, vacancy-type defects give rise to an internal friction maximum at 680 K (2 s(-1)) after quenching of FeAl. This reorientation effect as well as its recovery by long-range migration of defects is characterized by the above vacancy migration enthalpy. For the defects of the 680 K internal-friction maximum, a complex of a vacancy on the Fe sublattice and an antisite atom is suggested. A direct relationship between the high-temperature mechanical properties and atomic defects arises from the time dependence of the yield stress anomaly in Fe60Al40 measured after fast heating, which fits perfectly with the equilibration kinetics of the thermal vacancy concentration. From this we conclude that the yield stress anomaly is sensitively affected by thermal defects. C1 MAX PLANCK INST MET RES,D-70174 STUTTGART,GERMANY. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP Schaefer, HE (reprint author), UNIV STUTTGART,INST THEORET & ANGEW PHYS,PFAFFENWALDRING 57,D-70569 STUTTGART,GERMANY. RI Arzt, Eduard/B-5282-2008; George, Easo/L-5434-2014 NR 31 TC 57 Z9 59 U1 0 U2 6 PU AKADEMIE VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0031-8965 J9 PHYS STATUS SOLIDI A JI Phys. Status Solidi A-Appl. Res. PD APR 16 PY 1997 VL 160 IS 2 BP 531 EP 540 DI 10.1002/1521-396X(199704)160:2<531::AID-PSSA531>3.0.CO;2-7 PG 10 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA WY762 UT WOS:A1997WY76200025 ER PT J AU Ralle, M Bryan, JC Habenschuss, A Wunderlich, B AF Ralle, M Bryan, JC Habenschuss, A Wunderlich, B TI Low-temperature phase of tetraethylammonium bromide SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID STATE C-13 NMR; X = BR; ALKYLAMMONIUM SALTS; MESOPHASES; DISORDER; HOMOLOGS; MOTION AB The title compound, C8H20N+.Br-, exhibits a trigonal structure. Pairs of alkyl chains form all-trans sequences through the N atom. C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. RP Ralle, M (reprint author), UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996, USA. NR 15 TC 14 Z9 14 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD APR 15 PY 1997 VL 53 BP 488 EP 490 DI 10.1107/S0108270196015399 PN 4 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA WY708 UT WOS:A1997WY70800042 ER PT J AU Arlinghaus, HF Kwoka, MN Guo, XQ Jacobson, KB AF Arlinghaus, HF Kwoka, MN Guo, XQ Jacobson, KB TI Multiplexed DNA sequencing and diagnostics by hybridization with enriched stable isotope labels SO ANALYTICAL CHEMISTRY LA English DT Article ID RESONANCE IONIZATION SPECTROSCOPY; NUCLEIC-ACID; OLIGONUCLEOTIDES; CLONES; ATOMS; LEVEL; SIZE AB A new DNA diagnostic and sequencing system has been developed that uses time-of-flight resonance ionization mass spectrometry (TOF-RIMS) to provide a rapid method of analyzing stable isotope-labeled oligonucleotides in form 1 sequencing by hybridization (SBH). With form 1, the DNA is immobilized on a nylon membrane and enriched isotope-labeled individual oligonucleotide probes are free to seek out complementary DNAs during hybridization. The major advantage of this new approach is that multiple oligonucleotides can be labeled with different enriched isotopes and can all be simultaneously hybridized to the genosensor matrix. The probes can then be simultaneously detected with TOF-RIMS with high selectivity, sensitivity, and efficiency. By using isotopically enriched tin labels, up to 10 labeled oligonucleotides could be examined in a single hybridization to the DNA matrix. Greater numbers of labels are available if rare earth isotopes are employed. In the present study, matrices containing three different DNAs were prepared and simultaneously hybridized with two different probes under a variety of conditions. The results show that DNAs, immobilized on nylon surfaces, can be specifically hybridized to probes labeled with different enriched tin isotopes. Discrimination between complementary and noncomplementary sites of better than 100 was obtained in multiplexed samples. This new SBH method, which employs stable isotopic labels to locate target DNAs and TOF-RIMS to detect the labels, will be a very versatile and extensive multiplexing method. C1 OAK RIDGE NATL LAB,HLTH SCI RES DIV,OAK RIDGE,TN 37831. RP Arlinghaus, HF (reprint author), ATOM SCI INC,OAK RIDGE,TN 37830, USA. FU NIMH NIH HHS [1 R43 MH52938-01] NR 33 TC 9 Z9 9 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD APR 15 PY 1997 VL 69 IS 8 BP 1510 EP 1517 DI 10.1021/ac961206e PG 8 WC Chemistry, Analytical SC Chemistry GA WT631 UT WOS:A1997WT63100007 PM 9109351 ER PT J AU Muddiman, DC Anderson, GA Hofstadler, SA Smith, RD AF Muddiman, DC Anderson, GA Hofstadler, SA Smith, RD TI Length and base composition of PCR-amplified nucleic acids using mass measurements from electrospray ionization mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID ASSISTED LASER-DESORPTION; LARGE BIOMOLECULES; CHAIN-REACTION; DNA; POLYMERASE; 50-MER; RNA AB A generally applicable algorithm has been developed to allow base composition of polymerase chain reaction (PCR) products to be determined hem mass spectrometrically measured molecular weights and the complementary nature of DNA. Mass measurements of arbitrary precision for single-stranded DNA species are compatible with an increasingly large number of possible base compositions as molecular weight increases. For example, the number of base compositions that are consistent with a molecular weight of 35 000 is similar to 6000, based on a mass measurement precision of 0.01%. However, given the low misincorporation rate of standard DNA polymerases, mass measurement of both of the complementary single strands produced in the PCR reduces the number of possibilities to less than 100 at 0.01% mass precision, and base composition is uniquely defined at 0.001% mass precision. Taking into account the low misincorporation rate of standard DNA polymerases and the fact that the final PCR product also contains primers of known sequence (generally 15-20-mer in size, which flank the targeted region), this reduces the number of possible base combinations to only similar to 3 at MW = 35 000. In addition, the number of base pairs (i.e., length of the DNA molecule) is uniquely defined. We show that the use of modified bases in PCR or post-PCR modification chemistry allows unique solutions for the base composition of the PCR product with only modest mass measurement precision. C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, MACROMOL STRUCT & DYNAM, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 31 TC 75 Z9 76 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD APR 15 PY 1997 VL 69 IS 8 BP 1543 EP 1549 DI 10.1021/ac961134r PG 7 WC Chemistry, Analytical SC Chemistry GA WT631 UT WOS:A1997WT63100012 PM 9109353 ER PT J AU Ding, WL Fritz, JS AF Ding, WL Fritz, JS TI Separation of nonionic compounds by CE using a lauryl poly(oxyethylene) sulfate additive SO ANALYTICAL CHEMISTRY LA English DT Article ID ELECTROKINETIC CAPILLARY CHROMATOGRAPHY; NEUTRAL ORGANIC-MOLECULES; ZONE ELECTROPHORESIS; MICELLAR SOLUTIONS; SURFACTANT AB A nonionic surfactant (Brij-30) was treated with chlorosulfonic acid to form C12H25(OCH2CH2)(4)OSO3-Na+. Addition of a low concentration of this material to an aqueous solution-acetonitrile electrolyte makes it possible to separate nonionic organic compounds by capillary electrophoresis. Separation is based on differences in the stabilities of analyte-additive complexes in solution. Migration times of analytes can be varied over an unusually large range by varying the additive concentration and the proportion of acetonitrile in the electrolyte. This greatly expands the scope of neutral organic compounds that can be separated by CE. Several examples are given. Some very difficult separations were achieved, such as the baseline resolution of four methylbenz[a]anthracene isomers and the separation of normal and deuterated acetophenone. C1 US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV,DEPT CHEM,AMES,IA 50011. NR 15 TC 28 Z9 28 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD APR 15 PY 1997 VL 69 IS 8 BP 1593 EP 1597 DI 10.1021/ac961027x PG 5 WC Chemistry, Analytical SC Chemistry GA WT631 UT WOS:A1997WT63100019 ER PT J AU Arnold, GE Ornstein, RL AF Arnold, GE Ornstein, RL TI Protein hinge bending as seen in molecular dynamics simulations of native and M6I mutant T4 lysozymes SO BIOPOLYMERS LA English DT Article ID BACTERIOPHAGE-T4 LYSOZYME; BINDING-PROTEIN; ACTIVE-SITE; DOMAIN CLOSURE; MOTION; CONFORMATIONS; TRANSPORT; ISOMERASE; ENZYME; KINASE AB A dynamical model of interdomain ''hinge bending'' of T4 lysozyme in aqueous solution has been developed on the basis of molecular dynamics (MD) simulation. The MD model study provides a description of the conformational reorganization expected to occur for the protein in aqueous solution as compared to the crystalline environment. Thr ee different 500 ps molecular dynamics simulations were calculated, each using a distinctly different crystal conformation of T4 lysozyme as the starting points of the MD simulations. Crystal structures of wild-type lysozyme and ''open'' and ''closed'' forms of M61 variant structures were analyzed in this study. Large-scale, molecular-conformational rearrangements were observed in all three simulations, and the largest structural change was found for the open form of the M61 allomorph. All three simulated proteins had closed relative to the wild-type crystal structure, and the closure of the ''jaws'' of the active site cleft occurred gradually over the time course of the trajectories. The time average MD structures, calculated over the final 50 ps of each trajectory, had all adapted to conformations more similar to each other than to their incipient crystal forms. Using a similar MD protocol on cytochrome P450BM-3 [M. D. Paulsen and R. L. Ornstein (1995) Proteins: Structure Function and Genetics, Vol. 27, pp. 237-243] we have Sound that the opposite type of motion relative to the starting crystal structure, that is, the open form of the crystal structure, had opened to a greater degree relative to the incipient crystal structure form. Therefore we do not believe that either result is merely a simulation artifact, but rather the protein dynamics are due to protein relaxation in the absence of crystal packing forces in the simulated solution environments. (C) 1997 John Wiley & Sons, Inc. C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. NR 40 TC 21 Z9 21 U1 1 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0006-3525 J9 BIOPOLYMERS JI Biopolymers PD APR 15 PY 1997 VL 41 IS 5 BP 533 EP 544 DI 10.1002/(SICI)1097-0282(19970415)41:5<533::AID-BIP5>3.0.CO;2-N PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA WQ810 UT WOS:A1997WQ81000005 PM 9095676 ER PT J AU Rithidech, KN Dunn, JJ Gordon, CR Cronkite, EP Bond, VP AF Rithidech, KN Dunn, JJ Gordon, CR Cronkite, EP Bond, VP TI Evidence for an uncommon microsatellite instability on mouse chromosomes 2 and 4 and its possible role in radiation leukemogenesis SO BLOOD CELLS MOLECULES AND DISEASES LA English DT Article DE microsatellites; instability; leukemia; radiation; PCR ID MYELOID-LEUKEMIA; GENETIC INSTABILITY; HUMAN DNA; POLYMORPHISMS; AMPLIFICATION; DELETION; CELLS; ASSOCIATION; REPEATS; CANCER AB Although microsatellite instability (MSI), usually detected by DNA length polymorphisms, has been implicated in the induction of solid tumors in both humans and animals, its role in leukemogenesis is unclear. The goal of this study was to investigate whether there is an association between MSI and radiation leukemogenesis in CBA/Ca mice, Microsatellite lengths at 55 loci, mapped to eight different mouse chromosomes, were examined in two groups of DNA samples: 1) 10 normal DNA samples collected from the bone marrow cells of control male CBA/Ca mice, and 2) 17 DNA samples isolated from the spleens of mice that developed myeloid leukemia (ML) after exposure to neutrons, or X rays, or gamma rays. Microsatellite markers were amplified using the non-radioisotopic multiplex-touchdown PCR protocols developed in our laboratory, and the sizes of amplicons were examined on 6% non-denaturing polyacrylamide gels, Although no correlation between microsatellite length polymorphisms and radiation leukemogenesis was observed at the 55 CBA/Ca mouse loci tested in this study, an uncommon MSI, manifested as the absence of DNA bands after PCR amplification at 2 loci (D2MIT140 and D4MIT104), was observed in both control and ML samples. However, the frequency of ML samples showing this type of MSI is statistically significant (p<0.05). Although there is no direct evidence that this type of MSI predisposes mice to the development of leukemia, the results suggests that genes flanking the D2MIT140 and D4MIT104 are susceptible to spontaneous mutation and perhaps to damage caused by ionizing radiation. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. RP Rithidech, KN (reprint author), BROOKHAVEN NATL LAB,DEPT MED,30 BELL AVE,UPTON,NY 11973, USA. NR 45 TC 3 Z9 4 U1 0 U2 0 PU BLOOD CELLS FOUNDATION PI LA JOLLA PA C/O ERNEST BEUTLER SCRIPPS RES INST, DEPT MOLECULAR EXP MEDICINE, LA JOLLA, CA 92037 SN 1079-9796 J9 BLOOD CELL MOL DIS JI Blood Cells Mol. Dis. PD APR 15 PY 1997 VL 23 IS 7 BP 99 EP 109 DI 10.1006/bcmd.1997.0126 PG 11 WC Hematology SC Hematology GA WV493 UT WOS:A1997WV49300001 PM 9215755 ER PT J AU Hodis, HN Mack, WJ Dunn, M Liu, CR Selzer, RH Krauss, RM AF Hodis, HN Mack, WJ Dunn, M Liu, CR Selzer, RH Krauss, RM TI Intermediate-density lipoproteins and progression of carotid arterial wall intima-media thickness SO CIRCULATION LA English DT Article DE atherosclerosis; intima-media thickness; carotid arteries; coronary disease; lipoproteins ID TRIGLYCERIDE-RICH LIPOPROTEINS; CHOLESTEROL-RICH; DISEASE; ULTRASOUND; THERAPY; ATHEROSCLEROSIS; ANGIOGRAPHY; PREDICTORS; LOVASTATIN; PLASMA AB Background Although LDL cholesterol (LDL-C) is generally accepted to be a major risk factor for progression of atherosclerosis, the traditional measurement of LDL-C includes measurement of IDL. Little is known about the relationship between LDL and progression of atherosclerosis. Therefore, we investigated the association of plasma lipoprotein subclasses with progression of preintrusive carotid artery atherosclerosis in the Monitored Atherosclerosis Regression Study (MARS). Methods and Results MARS was a randomized, double-blind, placebo-controlled serial arterial imaging trial conducted in subjects 37 to 67 years old with angiographically defined coronary artery disease. Analytical ultracentrifugation was used to determine lipoprotein subclasses, including LDL (S-f 0 to 12), IDL (S-f 12 to 20), VLDL (S-f 20 to 400), and HDL (F-1.20 0 to 9) in 188 subjects. Subjects were randomized to a cholesterol-lowering diet plus placebo or lovastatin 80 mg/d. The outcome measure, the annual progression rate of the distal common carotid artery far wall intima-media thickness determined by high resolution B-mode ultrasonography, was determined at baseline and every 6 months on trial. When the major apolipoprotein B-containing lipoproteins were measured independently, IDL (r=.21, P<.005) but not VLDL (r=-.09, P=.24) or LDL (r=.09, P=.26) was associated with the progression of carotid artery intima-media thickness. Conclusions These data provide further evidence for the role of triglyceride-rich lipoproteins in the progression of atherosclerosis and support the evidence that indicates that the risk of atherosclerosis attributable to LDL-C may in part be the result of lipoproteins in the IDL fraction (S-f 12 to 20) that is included within the traditional measurements of LDL-C. C1 UNIV SO CALIF,SCH MED,STAT CONSULTAT & RES CTR,DEPT PREVENT MED,LOS ANGELES,CA 90033. CALTECH,JET PROP LAB,PASADENA,CA. UNIV CALIF BERKELEY,DONNER LAB,ERNEST ORLANDO LAWRENCE BERKELEY NATL LAB,BERKELEY,CA. RP Hodis, HN (reprint author), UNIV SO CALIF,SCH MED,ATHEROSCLEROSIS RES UNIT,DIV CARDIOL,DEPT MED,2250 ALCAZAR ST,CSC 132,LOS ANGELES,CA 90033, USA. FU NHLBI NIH HHS [R01-HL-49885, HL-18574] NR 21 TC 115 Z9 119 U1 0 U2 0 PU AMER HEART ASSOC PI DALLAS PA 7272 GREENVILLE AVENUE, DALLAS, TX 75231-4596 SN 0009-7322 J9 CIRCULATION JI Circulation PD APR 15 PY 1997 VL 95 IS 8 BP 2022 EP 2026 PG 5 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA WU760 UT WOS:A1997WU76000014 PM 9133510 ER PT J AU Hu, Y Prausnitz, JM AF Hu, Y Prausnitz, JM TI Stability theory for polydisperse fluid mixtures SO FLUID PHASE EQUILIBRIA LA English DT Article DE equation of state; lattice model; critical state; spinodal; continuous thermodynamics ID LIQUID-LIQUID EQUILIBRIA; CONTINUOUS THERMODYNAMICS; POLYMER-SOLUTIONS; MODEL AB Based on discrete multicomponent stability theory, a new method has been developed to obtain analytical expressions for spinodal and critical-point criteria for polydisperse fluid mixtures. This method is based on a theorem following from the classical theory of stability. Coupled with constraints (e.g. mole-fraction balance), this theorem yields analytical stability criteria for several multicomponent systems: a system containing one homologous series; a system containing one homologous series and one discrete component; and finally, a system containing an arbitrary number of homologous series and an arbitrary number of discrete components. The calculation procedure is much simpler than that using the classical determinant method. (C) 1997 Elsevier Science B.V. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP Hu, Y (reprint author), E CHINA UNIV SCI & TECHNOL,DEPT CHEM,SHANGHAI 200237,PEOPLES R CHINA. NR 16 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD APR 15 PY 1997 VL 130 IS 1-2 BP 1 EP 18 DI 10.1016/S0378-3812(96)03216-5 PG 18 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA XB292 UT WOS:A1997XB29200001 ER PT J AU Li, XL Baker, DN Temerin, M Larson, D Lin, RP Reeves, GD Looper, M Kanekal, SG Mewaldt, RA AF Li, XL Baker, DN Temerin, M Larson, D Lin, RP Reeves, GD Looper, M Kanekal, SG Mewaldt, RA TI Are energetic electrons in the solar wind the source of the outer radiation belt? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RELATIVISTIC ELECTRONS; SAMPEX AB Using data from WIND, SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer), and the Los Alamos National Laboratory (LANL) sensors onboard geostationary satellites, we investigate the correlation of energetic electrons in the 20-200 keV range in the solar wind and of high speed solar wind streams with relativistic electrons in the magnetosphere to determine whether energetic electrons in the solar wind are the source of the outer relativistic electron radiation belt. Though there is some correlation between energetic electron enhancements in the solar wind and enhancements in the outer radiation belt, the phase space density of 20-200 keV electrons in the solar wind is not adequate to supply the outer radiation belt electrons. Although lower energy electrons in the solar wind could be a seed population of the outer radiation belt, such lower energy electrons cannot achieve relativistic energies through the normal process of radial transport which conserves the first adiabatic invariant. Thus additional internal acceleration processes are required within the magnetosphere to produce the outer radiation belt. High speed solar wind streams are well correlated with increased magnetic activity and with increased fluxes in the outer radiation belt. The maximum correlation between the high speed streams and the radiation belt flux occurs with an increasing time delay for higher energies and and lower L values. We conclude that acceleration processes within the magnetosphere which are well correlated with high speed solar wind streams are responsible for the outer radiation belt electrons. C1 UNIV CALIF BERKELEY,SSL,BERKELEY,CA 94720. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771. HUGHES STX,GREENBELT,MD 20771. CALTECH,SPACE RADIAT LAB,PASADENA,CA 91125. AEROSP CORP,DEPT SPACE SCI,LOS ANGELES,CA 90009. RP Li, XL (reprint author), UNIV COLORADO,LASP,1234 INNOVAT DR,BOULDER,CO 80303, USA. RI Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 15 TC 96 Z9 106 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1997 VL 24 IS 8 BP 923 EP 926 DI 10.1029/97GL00543 PG 4 WC Geosciences, Multidisciplinary SC Geology GA WU965 UT WOS:A1997WU96500025 ER PT J AU Mehr, R Perelson, AS AF Mehr, R Perelson, AS TI Blind T-cell homeostasis and the CD4/CD8 ratio in the thymus and peripheral blood SO JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY LA English DT Article DE blind T-cell homeostasis; thymus; mathematical model ID HUMAN-IMMUNODEFICIENCY-VIRUS; BONE-MARROW CELLS; MONOCLONAL-ANTIBODIES; HIV-1 INFECTION; THYMOCYTE DEVELOPMENT; PROGENITOR CELLS; EPITHELIAL-CELLS; SUB-POPULATIONS; HELPER-INDUCER; LYMPHOCYTES-T AB We present a model of the dynamics of CD4 and CD8 T-cell subsets in the thymus and peripheral blood and use it to study the blind homeostasis hypothesis, which states that the total T-cell population in the periphery is subject to regulation rather than regulation of the CD4 or CD8 subsets individually. Our model reconstructs experimental observations by Adleman and Wofsy on the effects of CD4(+) T-cell depletion in mice. Our results point to the importance of the thymus in recovery from CD4(+) T-cell depletion and particularly to the need to hypothesize an intrathymic feedback regulation of T-cell production exerted by CD4(+) T cells. Our results support the blind homeostasis hypothesis for regulation of the peripheral blood levels of CD4(+) and CD8(+) T cells. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM. RP Mehr, R (reprint author), PRINCETON UNIV,DEPT BIOL MOL,SCHULTZ BLDG,ROOM 419,WASHINGTON RD,PRINCETON,NJ 08544, USA. FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI28433] NR 59 TC 20 Z9 20 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 1077-9450 J9 J ACQ IMMUN DEF SYND JI J. Acquir. Immune Defic. Syndr. Hum. Retrovirol. PD APR 15 PY 1997 VL 14 IS 5 BP 387 EP 398 PG 12 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA XC491 UT WOS:A1997XC49100001 PM 9170412 ER PT J AU Callahan, DA Langdon, AB Friedman, A Haber, I AF Callahan, DA Langdon, AB Friedman, A Haber, I TI The longitudinal wall impedance instability in a heavy-ion fusion driver SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ACCELERATOR; TARGET; BEAM AB For more than ten years [J. Bisognano, I. Haber, L, Smith, IEEE Trans, Nucl, Sci, NS-30, 2501 (1983)], the longitudinal wall impedance instability was thought to be a serious threat to the success of heavy-ion driven inertial confinement fusion. This instability is a ''resistive wall'' instability, driven by the impedance of the induction modules used to accelerate the beam. Early estimates of the instability growth rate predicted tells of e-folds due to the instability which would modulate the current and increase the longitudinal momentum spread and prevent focusing the ion beam on the small spot needed at the target. We have simulated this instability using an r-z particle-in-cell code which includes a model for the module impedance. These simulations, using driver parameters, show that growth due to the instability is smaller than in previous calculations. We have seen that growth is mainly limited to one head to tail transit by a space-charge wave. In addition, the capacitive component of the module impedance, which was neglected in the early work of Lee [E, P. Lee, Proc, Linear Accelerator Conference, (UCRL-86452), Santa Fe, NM, 1981] significantly reduces the growth rate. We have also included in the simulation intermittently applied axial confining fields which are thought to be the major source of perturbations to seed the longitudinal instability. Simulations show the beam can adjust to a systematic error in the longitudinal confining fields while a random error er;cites the most unstable wavelength of the instability. These simulations show that the longitudinal instability must be taken into account in a driver design, but it is not the major factor it was once thought to be, (C) 1997 American Institute of Physics. C1 USN,RES LAB,WASHINGTON,DC 20375. RP Callahan, DA (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 18 TC 3 Z9 3 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3398 EP 3409 DI 10.1063/1.365035 PN 1 PG 12 WC Physics, Applied SC Physics GA WV363 UT WOS:A1997WV36300010 ER PT J AU Shi, ZP Wang, Y Stocks, GM AF Shi, ZP Wang, Y Stocks, GM TI Ab initio study of biquadratic coupling in Fe/Cr multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RI Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 2 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3764 EP 3764 DI 10.1063/1.365500 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600006 ER PT J AU Sabiryanov, R Jaswal, SS Antropov, VP Harmon, BN Liu, S AF Sabiryanov, R Jaswal, SS Antropov, VP Harmon, BN Liu, S TI Spin dynamics studies of single Fe and Ni impurity in bcc iron SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 UNIV NEBRASKA,CTR MAT RES & ANAL,LINCOLN,NE 68588. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. NR 1 TC 0 Z9 0 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3872 EP 3872 DI 10.1063/1.364738 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600049 ER PT J AU Wang, Y Stocks, GM Nicholson, DMC Shelton, WA Antropov, VP Harmon, BN AF Wang, Y Stocks, GM Nicholson, DMC Shelton, WA Antropov, VP Harmon, BN TI Noncollinear magnetic structure in Ni0.35Fe0.65 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID FE-NI INVAR; ELECTRONIC-STRUCTURE; ALLOYS; ANTIFERROMAGNETISM; FERROMAGNETISM; IRON; MN AB Magnetic structure of NicFe1-c alloys in the INVAR region has long been a matter of great scientific interest and controversy. Using the locally self-consistent multiple scattering method, which has recently been extended to treat noncollinear magnetic systems, we studied the magnetic structure of Ni0.35Fe0.65 alloys. To simulate the alloys, we constructed a large fcc based sample which contains 256 sites occupied randomly by Ni and Fe atoms. The ground state magnetic structure is found to consist of noncollinear configurations associated with Fe-rich regions. In particular, Fe sites surrounded completely by other Fe atoms have antiferromagnetic alignments, while Fe sites having less than three Ni nearest-neighbors have a variety of noncollinear arrangements. (C) 1997 American Institute of Physics. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP Wang, Y (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 18 TC 39 Z9 39 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3873 EP 3875 DI 10.1063/1.364740 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600050 ER PT J AU FernandezBaca, JA Fawcett, E Alberts, HL Galkin, VY Endoh, Y AF FernandezBaca, JA Fawcett, E Alberts, HL Galkin, VY Endoh, Y TI Effect of pressure on the magnetic phase diagram of the antiferromagnetic spin density wave alloy Cr-1.6% Si SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID NEUTRON; ORDER AB A neutron diffraction experiment has been performed to study the effects of high pressure on the magnetic phase diagram of a single crystal specimen of Cr-1.6% Si. At applied pressures up to 0.49 GPa there are two clear transitions. At T-NC there is a transition from a paramagnetic (P) to a commensurate spin density wave (CSDW), while at lower temperatures there is a transition to a mixed state where the CSDW seems to coexist with an incommensurate SDW (ISDW) state. T-NC decreases with the application of pressure while the transition temperature T-CI to the mixed C-I state seems to be insensitive to pressure. At 0.69 GPa the ISDW state disappears while the P-C transition changes drastically. (C) 1997 American Institute of Physics. C1 UNIV TORONTO,TORONTO,ON M5S 1A7,CANADA. RAND AFRIKAANS UNIV,ZA-2006 JOHANNESBURG,SOUTH AFRICA. UNIV FED PARANA,BR-80060000 CURITIBA,PARANA,BRAZIL. TOHOKU UNIV,SENDAI,MIYAGI 98077,JAPAN. RP FernandezBaca, JA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Fernandez-Baca, Jaime/C-3984-2014 OI Fernandez-Baca, Jaime/0000-0001-9080-5096 NR 6 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3877 EP 3879 DI 10.1063/1.365053 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600052 ER PT J AU Dai, P FernandezBaca, JA Chakoumakos, BC Cable, JW Nagler, SE Schiffer, P Kalechofsky, N Roy, M Tsui, YK McGinn, PJ Einloth, SL Ramirez, AP AF Dai, P FernandezBaca, JA Chakoumakos, BC Cable, JW Nagler, SE Schiffer, P Kalechofsky, N Roy, M Tsui, YK McGinn, PJ Einloth, SL Ramirez, AP TI Structural and magnetic properties of La0.5Ca0.5MnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV NOTRE DAME,NOTRE DAME,IN 46556. LUCENT TECHNOL,BELL LABS,MURRAY HILL,NJ 07974. RI Nagler, Stephen/B-9403-2010; Nagler, Stephen/E-4908-2010; Schiffer, Peter/F-3227-2011; Dai, Pengcheng /C-9171-2012; Fernandez-Baca, Jaime/C-3984-2014; Chakoumakos, Bryan/A-5601-2016 OI Nagler, Stephen/0000-0002-7234-2339; Dai, Pengcheng /0000-0002-6088-3170; Fernandez-Baca, Jaime/0000-0001-9080-5096; Chakoumakos, Bryan/0000-0002-7870-6543 NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3883 EP 3883 DI 10.1063/1.365055 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600054 ER PT J AU Antropov, VP Tretyakov, SV Harmon, BN AF Antropov, VP Tretyakov, SV Harmon, BN TI Spin dynamics in magnets: Quantum effects and numerical simulations SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB We briefly review the key ideas and important physical approximations which are used to derive quantum dynamical equations of motion for the spin degrees of freedom in magnetic materials. This approach to spin dynamics uses first principles methods to obtain time and temperature dependent magnetic properties. A new stochastic approach to simulate time and temperature effects in extended spin systems is presented. Future applications and extensions are briefly covered. (C) 1997 American Institute of Physics. RP IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. NR 15 TC 22 Z9 22 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3961 EP 3965 DI 10.1063/1.365023 PN 2A PG 5 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600085 ER PT J AU Back, CH Weller, D Heidmann, J Mauri, D Garwin, EL Siegmann, HC AF Back, CH Weller, D Heidmann, J Mauri, D Garwin, EL Siegmann, HC TI Magnetic switching in ultrashort field pulses SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. IBM CORP,ALMADEN RES CTR,SAN JOSE,CA 95120. IBM CORP,STORAGE SYST DIV,SAN JOSE,CA 95193. ETH ZURICH,SOLID STATE PHYS LAB,CH-8093 ZURICH,SWITZERLAND. RI Back, Christian/A-8969-2012 OI Back, Christian/0000-0003-3840-0993 NR 3 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3966 EP 3966 DI 10.1063/1.365024 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600086 ER PT J AU Hwang, HY Dai, P Cheong, SW Aeppli, G Mook, HA Batlogg, B AF Hwang, HY Dai, P Cheong, SW Aeppli, G Mook, HA Batlogg, B TI Spin dynamics in ferromagnetic perovskite manganites SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 PRINCETON UNIV,JOSEPH HENRY LABS PHYS,PRINCETON,NJ 08544. AT&T BELL LABS,LUCENT TECHNOL,MURRAY HILL,NJ 07974. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NEC RES INST,PRINCETON,NJ 08540. RI Dai, Pengcheng /C-9171-2012; Hwang, Harold/I-6943-2012 OI Dai, Pengcheng /0000-0002-6088-3170; NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3967 EP 3967 DI 10.1063/1.364907 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600088 ER PT J AU Garrett, AW Nagler, SE Barnes, T Sales, BC AF Garrett, AW Nagler, SE Barnes, T Sales, BC TI Magnetic excitations in the spin ladder system (VO)(2)P2O7 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID SUSCEPTIBILITY; (VO)2P2O7 AB We present the results of elastic and inelastic neutron scattering measurements made on a powder sample of the spin-ladder compound (VO)(2)P2O7. The elastic scattering measurements made at a temperature of 10 K showed no magnetic structure, consistent with a singlet ground state. The inelastic measurements, also at 10 K, revealed three magnetic modes at 3.5, 6.0, and 14 meV. Theoretical treatments of spin ladder models point to an identification of the 3.5 meV mode as the minimum in the one-magnon dispersion, and the 14 meV mode as the local minimum in the associated two-magnon continuum. However, we have been unable to explain the scattering at 6.0 meV using existing theories of spin ladders. (C) 1997 American Institute of Physics. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,THEORET & COMPUTAT PHYS SECT,OAK RIDGE,TN 37831. RP Garrett, AW (reprint author), UNIV FLORIDA,DEPT PHYS,GAINESVILLE,FL 32611, USA. RI Nagler, Stephen/B-9403-2010; Nagler, Stephen/E-4908-2010 OI Nagler, Stephen/0000-0002-7234-2339 NR 10 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 3968 EP 3970 DI 10.1063/1.364908 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600089 ER PT J AU Brown, RH Nicholson, DMC Butler, WH Zhang, XG Shelton, WA Schulthess, TC MacLaren, JM AF Brown, RH Nicholson, DMC Butler, WH Zhang, XG Shelton, WA Schulthess, TC MacLaren, JM TI Calculation of the canting angle dependence of the resistivity in Cu vertical bar Co spin valves SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID GIANT MAGNETORESISTANCE; ANGULAR-DEPENDENCE; MULTILAYERS; SANDWICHES; EXCHANGE AB We consider the in-plane electrical conductivity of a spin valve, specifically, a system consisting of a copper slab between two cobalt slabs. We calculate the dependence of the resistivity on the canting angle, where the canting angle theta is defined as the angle between the magnetization vectors of two ferromagnetic slabs in a spin valve. To calculate the electronic structure, we utilize the layer-KKR formalism. Electron scattering by impurities, phonons, magnons, etc. is modeled using a layer and spin-dependent complex self-energy. Scattering rates are chosen to match Cu and Co resistivities. We assume a spin asymmetry scattering rate factor of 7 in Co, matching the Fermi-level minority-to-majority density-of-states ratio. No additional interfacial scattering is included. The nonlocal layer dependent conductivity is calculated using the Kubo-Greenwood formula for systems consisting of 3 and 7 monolayer fcc (111) Cu slabs in Co. We find electron channeling in Cu dominates the conductivity and at theta=pi/2 the resistivity is increased by 4.9% and 2.3% from a linear 1-cos theta dependence. We find giant magnetoresistive GMR values of 64% and 36% for 3 and 7 monolayers of Cu, respectively. (C) 1997 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. RP Brown, RH (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 16 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4008 EP 4010 DI 10.1063/1.364922 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600103 ER PT J AU Nicholson, DMC Butler, WH Shelton, WA Wang, Y Zhang, XG Stocks, GM MacLaren, JM AF Nicholson, DMC Butler, WH Shelton, WA Wang, Y Zhang, XG Stocks, GM MacLaren, JM TI Magnetic structure and electronic transport in permalloy SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB Permalloy (Ni0.8Fe0.2) is an important alloy for magnetic devices. We present calculations of the electronic and magnetic structure of permalloy and of an interdiffused interface between permalloy and copper. We also present the results of calculations of the transport properties of permalloy. We find that the magnetic moments in permalloy are collinear, however, there may be noncollinear moments near an interface between permalloy and copper. We find that the calculated electrical conductivity is very sensitive to the details of the electronic and magnetic structure, however calculations which include relativistic effects yield a value for the conductivity that is in reasonable agreement with experiment. (C) 1997 American Institute of Physics. C1 TULANE UNIV,DEPT PHYS,NEW ORLEANS,LA 70118. RP Nicholson, DMC (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Stocks, George Malcollm/Q-1251-2016 OI Stocks, George Malcollm/0000-0002-9013-260X NR 9 TC 13 Z9 13 U1 2 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4023 EP 4025 DI 10.1063/1.364924 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600108 ER PT J AU Felcher, GP Kleb, R Jaccarino, V AF Felcher, GP Kleb, R Jaccarino, V TI Antiferromagnetic domains and the spin-flop transition in MnF2 SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4075 EP 4075 DI 10.1063/1.365082 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600126 ER PT J AU Brewer, MA Echer, CJ Krishnan, KM Kobayashi, T Nakanishi, A AF Brewer, MA Echer, CJ Krishnan, KM Kobayashi, T Nakanishi, A TI Magnetic and physical microstructure of Fe16N2 films grown epitaxially on Si(001) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB Epitaxial Fe16N2 films were grown on Si(001) substrates with an Ag underlayer by reactive sputtering in nitrogen. Pure alpha'-Fe8N films were obtained which on subsequent annealing resulted in mixtures of alpha'-Fe8N (54%) and alpha ''-Fe16N2 (46%). An average moment of 1780 emu/cc, considerably larger than that of pure alpha-Fe (1714 emu/cc), was measured for both samples. Plan-view transmission electron microscopy of the films confirms the orientation relationship Fe16N2(001)parallel to Ag(001)parallel to Si(001) and Fe16N2[100]parallel to Ag[110]parallel to Si[100], and a small grain size (similar to 100 Angstrom), while electron energy-loss spectroscopy confirms an average composition of Fe8N for both samples. Electron diffraction patterns indicate that the as-deposited alpha' films already contain very small regions of ordered alpha '' which were not previously detected by x-ray diffraction measurements. Mossbauer spectroscopy performed at both 300 and 16 K gave three hyperfine fields corresponding to three different iron sites for both the unannealed alpha' and the annealed alpha'/alpha '' mixtures. Lorentzian fitting of the three iron components for the alpha'/alpha '' spectrum obtained at room temperature gave an intensity ratio of 1:2:1 (FeI:FeII:FeIII) corresponding to the expected occupancy for the three Fe sites in the Fe16N2 structure. Moreover, the pure alpha' film at 300 K and both samples at 16 K showed deviation from this distribution. The three components show notable differences in the temperature dependence of their occupancies; however, all three magnetic components deviate similarly from the surface normal. (C) 1997 American Institute of Physics. C1 UNIV CALIF SANTA BARBARA,DEPT MAT,SANTA BARBARA,CA 93106. SHIGA UNIV MED SCI,DEPT PHYS,OTSU,SHIGA 52021,JAPAN. RP Brewer, MA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 11 TC 13 Z9 13 U1 1 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4128 EP 4130 DI 10.1063/1.365102 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600147 ER PT J AU Hagmusa, IH Klaasse, JCP Bruck, E Prokes, K deBoer, FR Nakotte, H AF Hagmusa, IH Klaasse, JCP Bruck, E Prokes, K deBoer, FR Nakotte, H TI Specific heat of UNiGe in high magnetic fields SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB Specific-heat measurements were performed on a single crystal of UNiGe in magnetic fields up to 17.5 T. This compound crystallizes in the orthorhombic TiNiSi structure and undergoes two magnetic phase transitions at 41.5 and 50 K. Besides these transitions, the specific heat also shows a Schottky contribution due to the crystal-field splitting. The effects of an applied magnetic field are compared with results from previous neutron diffraction, magnetoresistance, and magnetization measurements. (C) 1997 American Institute of Physics. C1 LOS ALAMOS NATL LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545. RP Hagmusa, IH (reprint author), UNIV AMSTERDAM,VAN DER WAALS ZEEMAN INST,VALCKENIERSTR 65-67,NL-1018 XE AMSTERDAM,NETHERLANDS. RI Bruck, Ekkes/E-3365-2014 NR 13 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4157 EP 4159 DI 10.1063/1.364700 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600158 ER PT J AU Fishman, RS Jiang, XW AF Fishman, RS Jiang, XW TI Charge-density wave and magnetic phase diagram of chromium alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB The magnetic phase diagrams of all dilute Cr alloys can be explained by a simple theoretical model with coupled spin- and charge-density waves and a finite electron reservoir. If the charge-density wave and electron reservoir are sufficiently large, then the paramagnetic to commensurate spin-density wave transition becomes strongly first order, as found in Cr1-xFex and Cr1-xSix alloys. The observed discontinuity of the slope dT(N)/dx at the triple point and the bending of the configuration interaction phase boundary are also natural consequences of this model. (C) 1997 American Institute of Physics. C1 N DAKOTA STATE UNIV,DEPT PHYS,FARGO,ND 58105. RP Fishman, RS (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. RI Fishman, Randy/C-8639-2013 NR 23 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4201 EP 4203 DI 10.1063/1.365120 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600174 ER PT J AU Viswanath, VS Fishman, RS AF Viswanath, VS Fishman, RS TI Low frequency charge dynamics of incommensurate chromium alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MAGNETIC EXCITATIONS; WAVE AB Chromium alloys order as spin-density-wave (SDW) state antiferromagnets below the Neel temperature T-N. The formation of a SDW with wavevector Q(+/-)' is accompanied by the simultaneous formation of a charge-density-wave (CDW) with wavevector 2Q(+/-)'. We present the first results for the dynamics of the CDW within the random phase approximation. Phason modes arising from the translational invariance of the free energy are the only Goldstone modes involved in the charge dynamics of chromium alloys. The charge phasons have a nearly linear dispersion at low frequencies with a velocity which approaches the spin-wave velocity as T-->T-N. We obtain the neutron and x-ray scattering strengths and comment on the observability of the charge phasons. (C) 1997 American Institute of Physics. RP Viswanath, VS (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. RI Fishman, Randy/C-8639-2013 NR 16 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4204 EP 4206 DI 10.1063/1.365121 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600175 ER PT J AU Hicks, TJ Cable, JW AF Hicks, TJ Cable, JW TI Field dependent neutron scattering from Cu-Mn SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 MONASH UNIV,DEPT PHYS,CLAYTON,VIC 3168,AUSTRALIA. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4406 EP 4406 DI 10.1063/1.364840 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600253 ER PT J AU Lewis, LH Welch, DO Panchanathan, V AF Lewis, LH Welch, DO Panchanathan, V TI ''Exchange-spring'' Nd-Fe-B alloys: Investigations into reversal mechanisms and their temperature dependence SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MAGNETIC-PROPERTIES; PERMANENT-MAGNETS AB In order to investigate factors affecting coercivity a series of two-phase Nd2Fe14B-based nanocomposite alloys with different excess iron concentrations were produced by melt-spinning methods. The constituent grain size was estimated by diffraction methods to be in the range of 150-500 Angstrom, and room-temperature demagnetization curves verify that the alloys studied exhibit a modest remanence enhancement. Isothermal remanence magnetization (IRM) and de demagnetization (DCD) measurements performed at temperatures in the range 275 K less than or equal to T less than or equal to 350 K illustrate that the coercivity and irreversible magnetization develop in a bimodal, incoherent manner from a demagnetized state but upon demagnetization from a saturated state the system evinces collective, exchange-coupled behavior as illustrated by the reversible magnetization M-rev. The temperature dependencies and values of the irreversible susceptibility X-irr (DCD) suggest that a moderating phase with a magnetic anisotropy intermediate to the two constituent main phases may be present in the alloys. (C) 1997 American Institute of Physics. C1 MAGNEQUENCH INT MQI INC,ANDERSON,IN 46013. RP Lewis, LH (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 11 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4422 EP 4424 DI 10.1063/1.364789 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600261 ER PT J AU Welch, DO AF Welch, DO TI Theoretical analysis of chemical bonding and solute systematics in RE2TM17 and RE2TM4B compounds SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 BROOKHAVEN NATL LAB,DIV MAT SCI,DEPT APPL SCI,UPTON,NY 11973. NR 4 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4437 EP 4437 DI 10.1063/1.364794 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600266 ER PT J AU Keavney, DJ Fullerton, EE Pearson, JE Bader, SD AF Keavney, DJ Fullerton, EE Pearson, JE Bader, SD TI High-coercivity, c-axis oriented Nd2Fe14B films grown by molecular beam epitaxy SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MAGNETIC-PROPERTIES; THIN-FILMS; ANISOTROPY AB Thin films of Nd2Fe14B with a c-axis orientation and bulklike magnetic properties have been grown via molecular beam epitaxy with thicknesses as low as 300 Angstrom. The films are grown on single-crystal MgO(100) wafers overcoated with epitaxial Mo(100) buffer layers. The 2-14-1 phase is crystallized either by sequential deposition or codeposition of Fe, Nd, and B from pure elemental evaporation sources onto 600-700 degrees C substrates. The structure of each film was characterized in situ with reflection high-energy electron diffraction and ex situ with x-ray diffraction. For the sequentially deposited films, the in-plane saturation field is 60-70 kOe at 300 K, consistent with the bulk anisotropy field of 73 kOe. The spin-reorientation transition at 135 K can also be clearly seen in the in-plane and out-of-plane magnetization versus temperature data. The out-of-plane coercivities typically range from 15 to 20 kOe at 20 K, and from 3 to 8 kOe at 300 K. Codeposition results in a multiphase structure, with Nd2Fe14B show the minority phase. The multiphase structure results in reduced perpendicular anisotropy. (C) 1997 American Institute of Physics. RP Keavney, DJ (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 9 TC 44 Z9 44 U1 2 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4441 EP 4443 DI 10.1063/1.364969 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600268 ER PT J AU Kramer, MJ Li, CP Dennis, KW McCallum, RW Sellers, CH Branagan, DJ Shield, JE AF Kramer, MJ Li, CP Dennis, KW McCallum, RW Sellers, CH Branagan, DJ Shield, JE TI A generalized solidification model and microstructural verification for the Nd-Fe-B-Ti-C system processed by rapid solidification SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID ALLOYS AB For the Nd2Fe14B (2-14-1) compound, the optimal grain size should be smaller than the size of the single domain size of 150 nm. Transition metal carbides (TMC) also reduce the quench rate necessary to achieve the optimal or overquenched condition. This allows inert gas atomization (IGA) to produce viable magnetic materials. In this article we will demonstrate that optimal microstructure for the 2-14-1 can be produced by IGA with the addition of TiC. Moreover, a solidification model will be presented to show (1) how recalescence is a critical feature to the evolution of the microstructure in rapidly solidified materials and (2) the role TMC and other solute phases have on inhibiting grain growth so that lower quench rates can be employed. (C) 1997 American Institute of Physics. C1 LOCKHEED MARTIN IDAHO TECHNOL,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. UNIV UTAH,SALT LAKE CITY,UT 84112. RP Kramer, MJ (reprint author), IOWA STATE UNIV,AMES LAB,AMES,IA 50011, USA. NR 8 TC 18 Z9 18 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4459 EP 4461 DI 10.1063/1.364975 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600274 ER PT J AU Horton, JA Heatherly, L Sellers, CH Branagan, DJ Ragg, O Harris, IR AF Horton, JA Heatherly, L Sellers, CH Branagan, DJ Ragg, O Harris, IR TI Magnetic and mechanical properties of consolidated gas atomized and hydrogenation, disproportionation, desorption, and recombination Nd2Fe14B powders SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. UNIV BIRMINGHAM,BIRMINGHAM B15 2TT,W MIDLANDS,ENGLAND. NR 0 TC 0 Z9 0 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4462 EP 4462 DI 10.1063/1.364976 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600275 ER PT J AU Zhang, XG Butler, WH AF Zhang, XG Butler, WH TI Local field and quantum effects for current perpendicular to planes in multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID GIANT MAGNETORESISTANCE; METALLIC MULTILAYERS; LINEAR TRANSPORT; CONDUCTIVITY AB The calculation of giant magnetoresistance and in general, of electron transport for multilayers in the case of current perpendicular to the planes (CPP) requires both the two-point conductivity and the solution to the local field problem. In this paper we present a solution to the local field problem at an interface using two approaches. In the first approach we find the semiclassical solution for the local field when there is a band mismatch between two sides of an interface, and examine the deviation of the total resistance from the result of ''self-averaging,'' in the lowest order of the value of the potential step. In the second approach, we solve for the quantum correction to the local field through a numerical iterative scheme. The oscillations due to the quantum correction are surprisingly large, but their correction to the total resistance is remarkably small. Our results imply that the ''self-averaging'' of the resistance, which is usually assumed in analysis of CPP, is only approximate. (C) 1997 American Institute of Physics. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP Zhang, XG (reprint author), OAK RIDGE NATL LAB,COMPUTAT PHYS & ENGN DIV,POB 2008,OAK RIDGE,TN 37831, USA. NR 9 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4576 EP 4578 DI 10.1063/1.365433 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600318 ER PT J AU Hammar, PR Broholm, C Reich, DH Trouw, F AF Hammar, PR Broholm, C Reich, DH Trouw, F TI Cu-2(1,4-diazacycloheptane)(2)Cl-4: Spin-ladder system with competing interactions SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 ARGONNE NATL LABS,ARGONNE,IL 60439. JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218. RI Broholm, Collin/E-8228-2011 OI Broholm, Collin/0000-0002-1569-9892 NR 2 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4614 EP 4614 DI 10.1063/1.365179 PN 2A PG 1 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600331 ER PT J AU Mandrus, D Sarrao, JL Chakoumakos, BC FernandezBaca, JA Nagler, SE Sales, BC AF Mandrus, D Sarrao, JL Chakoumakos, BC FernandezBaca, JA Nagler, SE Sales, BC TI Magnetism in BaCoS2 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID INSULATOR AB BaCoS2 is a layered Mott-Hubbard insulator that orders antiferromagnetically near 300 K. We report magnetic susceptibility measurements on polycrystalline BaCoS2 from 77 to 800 K, and in- and out-of-plane measurements on single crystals from 2 to 350 K. We also report a powder neutron refinement of the magnetic structure of BaCoS2. The neutron measurements indicate that the moments lie in the plane, and that the magnetic unit cell is the same as the (orthorhombic) chemical cell. The ordered moment obtained from the neutron refinement is close to 3 mu(B), indicating that the Co ions are in the high-spin (S = 3/2) configuration. The effective moment inferred from the high temperature susceptibility, p = 5.26 mu(B), is also consistent with high-spin Co+2. (C) 1997 American Institute of Physics. C1 FLORIDA STATE UNIV,NATL HIGH MAGNET FIELD LAB,TALLAHASSEE,FL 32306. RP Mandrus, D (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37922, USA. RI Nagler, Stephen/B-9403-2010; Nagler, Stephen/E-4908-2010; Mandrus, David/H-3090-2014; Fernandez-Baca, Jaime/C-3984-2014; Chakoumakos, Bryan/A-5601-2016 OI Nagler, Stephen/0000-0002-7234-2339; Fernandez-Baca, Jaime/0000-0001-9080-5096; Chakoumakos, Bryan/0000-0002-7870-6543 NR 12 TC 9 Z9 9 U1 1 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4620 EP 4622 DI 10.1063/1.365182 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600335 ER PT J AU EscorciaAparicio, EJ Kawakami, RK Choi, HJ Qiu, ZQ AF EscorciaAparicio, EJ Kawakami, RK Choi, HJ Qiu, ZQ TI Role of film roughness and interdiffusion in the formation of nonferromagnetic fcc Fe in the Fe/Co(100) system SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID MAGNETIC PHASES; EPITAXIAL FE; CU(100); FE/CU(100) AB The fcc Fe/Cu(100) and Fe/Co(100) systems are characterized by a wide range of magnetic and structural phases. In particular, a nonferromagnetic fcc phase with a live layer has, been observed for room temperature growth Fe films in the similar to 5-11 ML thickness range. This nonferromagnetic phase is not present for low temperature (similar to 120 K) grown films even when the film temperature is raised to room temperature. Annealing the film at 475 K, however, will recover the room temperature phase. Two effects that could account for these features are interdiffusion and surface smoothening. In order to determine which of these effects is responsible for the occurrence of the nonferromagnetic phase, we performed experiments on the Fe/Co(100) system to separate these two effects. An artificially roughened sample grown at room temperature exhibits a ferromagnetic phase only. A sample grown at low temperature in which the first few layers are alloyed to simulate interdiffusion also shows the ferromagnetic phase. Experiments in which a few layers of varying thicknesses are grown at room temperature and the rest of the film is grown at low temperature exhibit different magnetic phases depending on the thickness of the room temperature grown layer. These results indicate that film roughness is the main factor that determines whether the nonferromagnetic phase of fcc Fe will be present in the similar to 5-11 ML thickness range. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP EscorciaAparicio, EJ (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Qiu, Zi Qiang/O-4421-2016 OI Qiu, Zi Qiang/0000-0003-0680-0714 NR 15 TC 3 Z9 3 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4714 EP 4716 DI 10.1063/1.365537 PN 2A PG 3 WC Physics, Applied SC Physics GA WV536 UT WOS:A1997WV53600371 ER PT J AU Nakotte, N Purwanto, A Robinson, RA VonDreele, RB Havela, L Prokes, K Sechovsky, V Pereira, LCJ Spirlet, JC Rebizant, J AF Nakotte, N Purwanto, A Robinson, RA VonDreele, RB Havela, L Prokes, K Sechovsky, V Pereira, LCJ Spirlet, JC Rebizant, J TI On the relationship between crystal structure and magnetism in U2Pd2Sn and U2Ni2In SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 CHARLES UNIV,PRAGUE 12116 2,CZECH REPUBLIC. COMMISS EUROPEAN COMMUNITIES,ITU,D-76125 KARLSRUHE,GERMANY. UNIV CALIF LOS ALAMOS NATL LAB,MLNSC,LOS ALAMOS,NM 87544. RI Pereira, Laura/G-3579-2013; Sechovsky, Vladimir/A-5256-2008 OI Pereira, Laura/0000-0002-8818-0039; Sechovsky, Vladimir/0000-0003-1298-2120 NR 1 TC 0 Z9 0 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4927 EP 4927 DI 10.1063/1.364998 PN 2B PG 1 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700067 ER PT J AU Sternlieb, B Stassis, C Goldman, AI Canfield, PC Shapiro, S AF Sternlieb, B Stassis, C Goldman, AI Canfield, PC Shapiro, S TI Single crystal neutron diffraction study of the magnetic structure of TmNi2B2C SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID SUPERCONDUCTIVITY; ORDER; DYNI2B2C; HONI2B2C; ERNI2B2C AB Neutron diffraction techniques have been used to study the magnetic structure of single crystals of the magnetic superconductor (T-c congruent to 11 K) TmNi2B2C. We find that below approximately 1.5 K the magnetic moments order in an incommensurate spin wave with propagation vector q(m) = q(m)(a*+b*) [or q(m) = q(m)(a*-b*)] with q(m) = 0.094 +/- 0.001. The spin wave is transverse with the moments aligned along the c axis, and the observation of relatively intense higher-order harmonics shows that the modulation is not purely sinusoidal but considerably squared. This incommensurate magnetic structure, which coexists with superconductivity below T-N congruent to 1.5 K, is quite different from those observed in the magnetic superconductors HoNi2B2C and ErNi2B2C. The origin of diffraction peaks observed in scans parallel to a* is briefly discussed. (C) 1997 American Institute of Physics. C1 IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. IOWA STATE UNIV SCI & TECHNOL, DEPT PHYS & ASTRON, AMES, IA 50011 USA. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RP Sternlieb, B (reprint author), BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. RI Canfield, Paul/H-2698-2014 NR 23 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 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4937 EP 4939 DI 10.1063/1.365003 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700071 ER PT J AU Adenwalla, S Fullerton, EE Felcher, GP AF Adenwalla, S Fullerton, EE Felcher, GP TI Neutron standing wave resonator to measure the flux line lattice in thin film superconducting samples SO JOURNAL OF APPLIED PHYSICS LA English DT Meeting Abstract C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RI Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 4943 EP 4943 DI 10.1063/1.365005 PN 2B PG 1 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700073 ER PT J AU Picconatto, JJ Pechan, MJ Fullerton, EE AF Picconatto, JJ Pechan, MJ Fullerton, EE TI Magnetic anisotropy, coupling, and transport in epitaxial Co/Cr superlattices on MgO(100) and (110) substrates SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID GIANT MAGNETORESISTANCE AB Superlattices of Co/Cr have been epitaxially sputtered onto MgO(100) and (110) substrates coated with epitaxial Cr(100) and (211) buffer layers. The Co thickness is fixed at 20 Angstrom and the Cr thickness varied from 7 to 22 Angstrom. On the MgO(110)/Cr(211) substrates, coherent hcp-Co(<1(1)over bar 00>)/bcc-Cr(211) superlattice structures are formed. On MgO(100)/Cr(100), x-ray-diffraction results suggest strained hcp-Co(11(2) over bar)/bcc-Cr(100) superlattices. Magnetization measurements show fourfold magnetic in-plane anisotropy for the MgO(100) orientation and twofold for the MgO(110). By utilizing a simple model based upon perpendicular uniaxial anisotropies, we have concluded that the fourfold anisotropy has its origin in the second-order uniaxial Co anisotropy energy. The antiferromagnetic interlayer coupling strength exhibits a maximum value of 0.15 erg/cm(2) at a Cr thickness of 13 Angstrom in the MgO(110) orientation. The MgO(100) orientation exhibits its strongest coupling of 0.55 erg/cm(3) at 10 Angstrom Cr thickness. Modest giant magnetoresistance values no larger than 3% are observed and we find no evidence of enhanced anisotropic magnetoresistance effects recently reported for Co(<1(1)over bar 00>)/Cr(211) superlattices. (C) 1997 American Institute of Physics. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Picconatto, JJ (reprint author), MIAMI UNIV,DEPT PHYS,OXFORD,OH 45056, USA. RI Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 10 TC 10 Z9 10 U1 3 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5058 EP 5060 DI 10.1063/1.364507 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700124 ER PT J AU Lewis, LH Welch, DO AF Lewis, LH Welch, DO TI Crystallographic texture determinations from inverse susceptibility measurements SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys ID ND2FE14B; PR2FE14B AB Determination of the quantitative relationship between crystallographic texture and magnetic properties in advanced permanent magnets may be hampered by complex microstructures, which complicate methods that rely on diffraction, or by interparticulate interactions, which adversely affect methods based on magnetic remanence measurements. To this end, new techniques in the determination of texture of bulk permanent magnets are being explored to overcome these inherent experimental difficulties. The analysis of inverse paramagnetic susceptibility measurements constitutes a new method to investigate crystallographic texture. Such measurements also provide Curie temperature data, which are sensitive to chemical changes that may have occurred in the magnetic phase during processing. The mathematical formalism underlying the analysis of inverse susceptibility measurements is outlined, and is used to evaluate magnetic measurements taken from a series of Nd2Fe14B magnets that have been processed by different means, and thus contain different degrees of texture. While this method does provide qualitative information concerning the relative crystallographic alignment of magnet samples, it needs calibration to obtain an explicit value for a texture order parameter. (C) 1997 American Institute of Physics. RP Lewis, LH (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 11 TC 0 Z9 1 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1997 VL 81 IS 8 BP 5091 EP 5093 DI 10.1063/1.364953 PN 2B PG 3 WC Physics, Applied SC Physics GA WV537 UT WOS:A1997WV53700137 ER PT J AU Wang, JY Lewis, LH Zhu, Y Welch, DO Sellers, CH Branagan, DJ Panchanathan, V AF Wang, JY Lewis, LH Zhu, Y Welch, DO Sellers, CH Branagan, DJ Panchanathan, V TI Transmission electron microscopy of as-quenched inert gas atomized particles: Effect of alloying additions in Nd2Fe14B SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 41st Annual Conference on Magnetism and Magnetic Materials CY NOV 12-15, 1996 CL ATLANTA, GA SP Amer Inst Phys AB It is known that the addition of alloying elements to the Nd2Fe14B-based alloys significantly inhibits the onset of the crystallization in particles produced by the inert gas atomization (IGA) process. Transmission electron microscopy (TEM) was performed on a selection of as-atomized particles synthesized by IGA methods with the addition of 3 wt % TiC. TEM samples were successfully prepared using the wedge technique. Large particles (>10 mu m) tend to consist of well-defined grains of Nd2Fe14B while the submicron size particles are generally amorphous and particles with diameter d in the size range, 1 mu m2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA WV759 UT WOS:A1997WV75900011 ER PT J AU Sweetser, JN Fittinghoff, DN Trebino, R AF Sweetser, JN Fittinghoff, DN Trebino, R TI Transient-grating frequency-resolved optical gating SO OPTICS LETTERS LA English DT Article ID PHASE; INTENSITY; PULSES AB We introduce a transient-grating beam geometry for frequency-resolved optical-gating measurements of ultrashort laser pulses and show that it offers significant advantages over currently used geometries. Background free and phase matched over a long interaction length, it is the most sensitive third-order pulse-measurement geometry. In addition, for pulses greater than similar to 300 fs in length and similar to 1 mu J in energy, the nonlinear medium can be removed and the nonlinearity of air can be used to measure the pulse. (C) 1997 Optical Society of America. RP Sweetser, JN (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 7 TC 64 Z9 66 U1 6 U2 20 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD APR 15 PY 1997 VL 22 IS 8 BP 519 EP 521 DI 10.1364/OL.22.000519 PG 3 WC Optics SC Optics GA WU315 UT WOS:A1997WU31500011 PM 18183253 ER PT J AU Wachter, EA Fisher, WG AF Wachter, EA Fisher, WG TI Coherent-burst laser ranging: Decoupling resolution and unambiguous range SO OPTICS LETTERS LA English DT Article ID DOMAIN OPTICAL REFLECTOMETER; MODULATION CW LIDAR AB A novel signal encoding and decoding method for laser ranging is proposed and experimentally demonstrated. The coherent-burst method uses a quasi-continuous interrupted burst of modulated laser radiation to achieve high-precision ranging at all distances. Both time of flight and phase shift are determined based on modulation provides high absolute precision, while measured temporal delay from transmission to reception eliminates potential uncertainty from aliasing. The method is demonstrated with low-power diode lasers that can be modulated at frequencies in excess of 250 MHz. (C) 1997 Optical Society of America. RP Wachter, EA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 15 TC 6 Z9 7 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD APR 15 PY 1997 VL 22 IS 8 BP 570 EP 572 DI 10.1364/OL.22.000570 PG 3 WC Optics SC Optics GA WU315 UT WOS:A1997WU31500028 PM 18183270 ER PT J AU Deisz, JJ Eguiluz, AG AF Deisz, JJ Eguiluz, AG TI Energy dependence of quasiparticle damping at a metal surface SO PHYSICAL REVIEW B LA English DT Article ID IMAGE-POTENTIAL STATES; LIFETIME; ELECTRON; BAND AB We evaluate the energy dependence of the imaginary part of the electron self-energy Im Sigma in the vicinity of a metal surface modeled with jellium via numerical calculations based on the GW approximation. When the electron is inside the surface, conventional quadratic scaling, IM Sigma similar or equal to(E-E-F)(2) for E-->E-F, holds for electron positions all the way to the jellium edge and for energies at least up to the vacuum level E-E-F similar or equal to 4 eV. However, when the electron is in the vacuum outside the surface, large departures from quadratic scaling are obtained for most energies for which it holds in the bulk. These departures grow as the electron-surface separation increases. This effect is traced to the suppression of one-electron decay channels near the Fermi level. C1 GEORGETOWN UNIV, DEPT PHYS, WASHINGTON, DC 20057 USA. UNIV TENNESSEE, DEPT PHYS & ASTRON, KNOXVILLE, TN 37996 USA. OAK RIDGE NATL LAB, DIV SOLID STATE, OAK RIDGE, TN 37831 USA. OI Deisz, John/0000-0003-3346-0954 NR 18 TC 7 Z9 7 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 15 BP 9195 EP 9199 DI 10.1103/PhysRevB.55.9195 PG 5 WC Physics, Condensed Matter SC Physics GA WV251 UT WOS:A1997WV25100001 ER PT J AU Collins, PG Zettl, A AF Collins, PG Zettl, A TI Unique characteristics of cold cathode carbon-nanotube-matrix field emitters SO PHYSICAL REVIEW B LA English DT Article ID ELECTRON-EMISSION; COMPOSITE; MICROTUBULES AB The attributes of electron field emission from disordered matrix arrays of carbon nanotubes are studied and found to be quite reproducible in spite of the disorder, density, and quality variations from sample to sample. At low applied electric fields, the electron field emission current-voltage characteristics qualitatively follow conventional Fowler-Nordheim behavior up to a critical current density. However, the current rise at low applied fields is anomalously steep, suggesting that the Fowler-Nordheim model is not sufficient to quantitatively characterize the emission. In the high-field region, the emission characteristics have a more complex behavior. In that regime, the instantaneous field emission is reminiscent of the low-field behavior, but discrete switching events lead to an overall current suppression. We attribute the sudden and well-defined onset of the switching events to interactions between neighboring nanotube tips. By correlating the switching behavior to the current-voltage characteristics, we rule out other physical processes that cause similar effects. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Collins, PG (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Zettl, Alex/O-4925-2016 OI Zettl, Alex/0000-0001-6330-136X NR 28 TC 347 Z9 364 U1 1 U2 33 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 15 BP 9391 EP 9399 DI 10.1103/PhysRevB.55.9391 PG 9 WC Physics, Condensed Matter SC Physics GA WV251 UT WOS:A1997WV25100051 ER PT J AU Benioff, P AF Benioff, P TI Transmission and spectral aspects of tight-binding Hamiltonians for the counting quantum Turing machine SO PHYSICAL REVIEW B LA English DT Article ID TRACE MAPS; THUE-MORSE; SUBSTITUTION SEQUENCES; ELECTRICAL-RESISTANCE; LANDAUER RESISTANCE; CANTOR SPECTRA; COMPUTERS; FIBONACCI; SYSTEMS; COMPUTATION AB One-dimensional (1D) systems with deterministic disorder, such as those with quasiperiodic or substitutional sequence potential distributions, have been extensively studied. It was recently shown that a generalization of quantum Turing machines (QTM's), in which potentials are associated with elementary steps or transitions of the computation, generates potential distributions along computation paths of stales in some basis B, which are computable and are thus periodic or have deterministic disorder. These generalized machines (GQTM's) can be used to investigate the effect of potentials in causing reflections and reducing the completion probability of computations. This paper expands on this work by determining the spectral and transmission properties of an example GQTM, which enumerates the integers in succession as binary strings. A potential is associated with just one type of step. For many computation paths the potential distributions are initial segments of a distribution that is quasiperiodic and corresponds to a substitution sequence. Thus the methods developed in the study of 1D systems can be used to calculate the energy band spectra and Landauer resistance (LR). For energies below the barrier height, the LR fluctuates rapidly with momentum with minima close to or at band-gap edges. Also for several values of the parameters involved there is good transmission over some momentum regions. RP Benioff, P (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 56 TC 3 Z9 3 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 15 BP 9482 EP 9494 DI 10.1103/PhysRevB.55.9482 PG 13 WC Physics, Condensed Matter SC Physics GA WV251 UT WOS:A1997WV25100061 ER PT J AU Choi, IH Yu, PY AF Choi, IH Yu, PY TI Pressure dependence of defects and p-d hybridization in chalcopyrite semiconductors SO PHYSICAL REVIEW B LA English DT Article ID ALXGA1-XAS ALLOYS; ENERGY-GAP; AGGAS2; CUGAS2; GAAS AB We have studied the effect of pressure on optical transitions involving defects in the photoluminescence spectra of two chalcopyrite semiconductors AgGaS2 and CuGaS2. In the former compound results obtained in samples doped with either Cd or Au are compared with unintentionally doped samples. In both compounds we find transitions whose pressure coefficients are larger than that of the band gap. We have identified these transitions as involving deep accepters. We propose that in the chalcopyrite semiconductors the valence-band edge can be less pressure dependent than the deep accepters because of p-d hybridization in the valence-band wave functions. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Choi, IH (reprint author), CHUNG ANG UNIV,DEPT PHYS,SEOUL 156756,SOUTH KOREA. NR 29 TC 15 Z9 15 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 15 BP 9642 EP 9648 DI 10.1103/PhysRevB.55.9642 PG 7 WC Physics, Condensed Matter SC Physics GA WV251 UT WOS:A1997WV25100082 ER PT J AU Wampler, WR AF Wampler, WR TI Transmission-ion-channeling studies of the silicon (111) monohydride surface SO PHYSICAL REVIEW B LA English DT Article ID ABSOLUTE CROSS-SECTION; H-TERMINATED SI(111); ADSORPTION-POSITION; HYDROGEN; DEUTERIUM; MICROSCOPY; LOCATION; DEFECTS; STM AB Transmission ion channeling was used to examine the atomic position of deuterium on the silicon (111) monohydride surface. A 2-MeV He-4(+)-ion beam was used to elastically recoil deuterium from the beam-exit surface of a thin silicon crystal. The yield of recoiled deuterium was measured versus angle between the analysis beam and the channeling axis near the [111], [110], and [100] axes. The location of the surface deuterium relative to the silicon lattice vias examined by comparing the measured yields with computer simulations of ion channeling. Channeling measurements were consistent with approximately half of the deuterium occupying a site close to the site predicted by nb initio calculations of the structure for the Si(111) 1x1 monohydride surface, with the remaining deuterium being disordered or displaced from the predicted site. RP Wampler, WR (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 29 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 15 BP 9693 EP 9698 DI 10.1103/PhysRevB.55.9693 PG 6 WC Physics, Condensed Matter SC Physics GA WV251 UT WOS:A1997WV25100088 ER PT J AU Shan, YY Lynn, KG AsokaKumar, P Fung, S Beling, CB AF Shan, YY Lynn, KG AsokaKumar, P Fung, S Beling, CB TI Low-temperature positron transport in semi-insulating GaAs SO PHYSICAL REVIEW B LA English DT Article ID MONTE-CARLO CALCULATIONS; MONOENERGETIC POSITRONS; KEV ELECTRON; DIFFUSION; SURFACES; MOBILITY; SI; INTERFACE; SOLIDS; ANNIHILATION AB Positron diffusion and drift in semi-insulating (SI) GaAs in the temperature range of 50-309 K were studied by the slow-positron beam technique. Both the temperature-dependent positron diffusion coefficient and positron mobility were measured independently using the method reported recently [Y. Y. Shan et al., Phys. Rev. B 54, 1982 (1996)]. The experimental results are consistent with the Einstein relation. The diffusion coefficient and mobility approximately follow D+(T) = 9400T(-beta) cm(2) s(-1), and mu(+)(T) = 10(8) x T-sigma cm(2) V-1 s(-1), with beta = 1.5+/-0.1, and sigma = 2.5+/-0.2, respectively in the temperature range of 50-300 K. The results are consistent with scattering from optical-phonon modes as the dominant scattering process for positron transport in GaAs (SI) in this temperature range. No trapped positron states were observed to 50 K. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. UNIV HONG KONG,DEPT PHYS,HONG KONG,HONG KONG. RP Shan, YY (reprint author), WASHINGTON STATE UNIV,DEPT PHYS,PULLMAN,WA 99164, USA. NR 40 TC 7 Z9 8 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 15 BP 9897 EP 9903 DI 10.1103/PhysRevB.55.9897 PG 7 WC Physics, Condensed Matter SC Physics GA WV251 UT WOS:A1997WV25100114 ER PT J AU Delin, A Oppeneer, PM Brooks, MSS Kraft, T Wills, JM Johansson, B Eriksson, O AF Delin, A Oppeneer, PM Brooks, MSS Kraft, T Wills, JM Johansson, B Eriksson, O TI Optical evidence of 4f-band formation in CeN SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; PHOTOEMISSION SPECTRA; 2-PEAK PHOTOEMISSION; CERIUM; ENERGY; SYSTEMS; METALS; MODEL AB We report ab initio calculations of the ground state and optical properties of CeN, which show that the 4f electrons in CeN are itinerant and that the intra-atomic 4f-Coulomb interaction is largely screened. A coherent 4f band of width similar to 2 eV is formed, from which an accurate description of the optical spectrum is obtained. The lattice parameter, linear specific heat coefficient, and magnetic susceptibility are also well reproduced. While CeN was previously classified to be a mixed Valence compound, our results show that the more appropriate picture is that of a 4f-band material. C1 DRESDEN UNIV TECHNOL,MAX PLANCK RES GRP ELECTRON SYST,D-01062 DRESDEN,GERMANY. COMMISS EUROPEAN COMMUNITIES,EUROPEAN INST TRANSURANIUM ELEMENTS,D-76125 KARLSRUHE,GERMANY. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV UPPSALA,DEPT PHYS,CONDENSED MATTER THEORY GRP,S-75121 UPPSALA,SWEDEN. RP Delin, A (reprint author), UPPSALA UNIV,DEPT PHYS,CONDENSED MATTER THEORY GRP,S-75121 UPPSALA,SWEDEN. RI Eriksson, Olle/E-3265-2014; Delin, Anna/P-2100-2014 OI Eriksson, Olle/0000-0001-5111-1374; Delin, Anna/0000-0001-7788-6127 NR 38 TC 33 Z9 33 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10173 EP 10176 PG 4 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300007 ER PT J AU Haug, K Zhang, ZY John, D Walters, CF Zehner, DM Plummer, WE AF Haug, K Zhang, ZY John, D Walters, CF Zehner, DM Plummer, WE TI Effects of hydrogen in Ni(100) submonolayer homoepitaxy SO PHYSICAL REVIEW B LA English DT Article ID BY-LAYER GROWTH; SCANNING TUNNELING MICROSCOPY; SURFACE-DIFFUSION; VACANCY ISLANDS; BROWNIAN-MOTION; NICKEL SURFACES; SELF-DIFFUSION; CLUSTERS; MECHANISMS; IMPURITIES AB The effects of hydrogen in Ni(100) submonolayer homoepitaxy have been investigated by classical-potential total-energy calculations with semiclassical hydrogen zero-point-energy corrections. The fast diffusion of H on a flat Ni(100) surface is found to persist even when the surface is decorated with various intrinsic defects such as Ni adatoms, islands, and steps created during epitaxial growth. On the other hand, the presence of H significantly enhances the mobility of both Ni adatoms and Ni islands, resulting in a decrease in the Ni island density and a corresponding increase in the average island size. These results suggest that hydrogen will function as an antisurfactant in Ni(100) homoepitaxy. Connections to available experiments are made. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. RP Haug, K (reprint author), LEHIGH UNIV,DEPT CHEM,BETHLEHEM,PA 18015, USA. NR 36 TC 14 Z9 14 U1 5 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10233 EP 10236 PG 4 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300022 ER PT J AU Zhang, XG Butler, WH AF Zhang, XG Butler, WH TI Landauer conductance in the diffusive regime SO PHYSICAL REVIEW B LA English DT Article ID METALLIC MULTILAYERS; LINEAR TRANSPORT; SCALING THEORY; FORMULA; RESISTANCE; LOCALIZATION; CONDUCTIVITY AB We present a derivation of the de Landauer conductance formula in three dimensions starting from a mean-field approximation of the Kubo formula using a Green function for electron propagation that contains a self-energy that may be complex. Unlike some previous derivations of the Landauer formula from the Kubo formula, we find a nonzero contribution to the current from the volume integral over the leads, even without the mean-field approximation. Because we use a complex self-energy to describe the sample, the sum of the reflection and the transmission probabilities is in general less than one. In the four-probe case the conductance of a sample with length L, electron mean free path I, transmission amplitude t(k(parallel to)), and reflection amplitude r(k(parallel to)) is given by (e(2)/h)2N Sigma(k parallel to)[1-\r\(2)-(1-\r\(2)-\t\(2))C]/Sigma(k parallel to)(1+\r\(2)-\t\(2)) for each spin, where N is the number of channels and C=1/(1-e(-L/lcos theta))-lcos theta/L with cos theta=\k(parallel to)\/k(F). In the diffusive limit L much greater than l we obtain the three-dimensional Boltzmann solution. In the ballistic limit L much less than l we obtain one-dimensional Boltzmann solutions for N independent channels. If one applies the multiprobe one-dimensional Buttiker formula to a system where R+T less than or equal to 1, one reproduces our result for a single channel. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP Zhang, XG (reprint author), OAK RIDGE NATL LAB,COMPUTAT PHYS & ENGN DIV,POB 2008,OAK RIDGE,TN 37831, USA. NR 24 TC 7 Z9 7 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10308 EP 10318 DI 10.1103/PhysRevB.55.10308 PG 11 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300033 ER PT J AU LawniczakJablonska, K Perera, RCC Underwood, JH Gullikson, EM Iwanowski, RJ AF LawniczakJablonska, K Perera, RCC Underwood, JH Gullikson, EM Iwanowski, RJ TI Hybridization of the 3d states of transition metals with the states of the ZnS matrix SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-ABSORPTION; ELECTRONIC-STRUCTURE; TERNARY ALLOYS; FINE-STRUCTURE; XANES; EDGE; ZINC AB The near-edge soft x-ray absorption spectra of Zn1-xMxS compounds (where M is Mn, Fe, Co, and Ni, and x ranges to the solubility Limit) have been obtained by measuring the total electron yield (photoelectron, Auger and secondary) from the sample in an ultrahigh vacuum (UHV) sample chamber using x-rays from beam line 6.3.2, a bending magnet beamline at the Advanced Light Source (ALS). The high spectral resolution of the beamline in the 50-1000 eV region allowed detailed measurements of S-L-2,L-3 and transition metal L-3 absorption spectra. The study of d and s antibonding states in Zn1-xMxS compounds provided evidence that 3d states of transition metals participate in the formation of ionic-covalence bonding between M-S. Furthermore, it was found that the ability of 3d electrons to participate in bonding decreases with increasing 3d orbit filling. As the 3d orbit becomes more closed, the 3d electrons assume a more corelike character. The evidence of these behaviors can be seen in the metal and sulfur L absorption spectra as well as in the charge transfer values calculated from the energy shifts in transition metal K edges. These findings provided an explanation for the drastic decrease in the solubility of these particular metals in the ZnS matrix. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR XRAY OPT,BERKELEY,CA 94720. RP LawniczakJablonska, K (reprint author), POLISH ACAD SCI,INST PHYS,AL LOTNIKOW 32-46,PL-02668 WARSAW,POLAND. RI Lawniczak-Jablonska, Krystyna/J-8994-2012 OI Lawniczak-Jablonska, Krystyna/0000-0003-1042-570X NR 24 TC 12 Z9 12 U1 3 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10376 EP 10381 DI 10.1103/PhysRevB.55.10376 PG 6 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300039 ER PT J AU Hsu, L Zehender, S Bauser, E Haller, EE AF Hsu, L Zehender, S Bauser, E Haller, EE TI Pressure-induced shallow donor transformations in gallium arsenide SO PHYSICAL REVIEW B LA English DT Article ID III-V-SEMICONDUCTORS; CONFINED HOLE STATES; QUANTUM-WELL SYSTEM; BACK BAND-STRUCTURE; CAMELS-BACK; HYDROSTATIC-PRESSURE; PHOTO-LUMINESCENCE; BOUND-STATES; GAAS; DEPENDENCE AB Using hydrostatic pressure, we have transformed GaAs into an indirect band-gap semiconductor with a conduction-band minimum near the X point of the Brillouin zone. Ground to bound excited-state transitions of X-point group-IV donors in GaAs are investigated using broadband far-infrared Fourier-transform absorption spectroscopy. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. MAX PLANCK INST SOLID STATE RES,D-70506 STUTTGART,GERMANY. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP Hsu, L (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 31 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10515 EP 10518 DI 10.1103/PhysRevB.55.10515 PG 4 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300053 ER PT J AU Regan, MJ Tostmann, H Pershan, PS Magnussen, OM DiMasi, E Ocko, BM Deutsch, M AF Regan, MJ Tostmann, H Pershan, PS Magnussen, OM DiMasi, E Ocko, BM Deutsch, M TI X-ray study of the oxidation of liquid-gallium surfaces SO PHYSICAL REVIEW B LA English DT Article ID OXIDE-GROWTH; REFLECTIVITY; GA; MERCURY AB The oxidation of liquid-gallium surfaces has been investigated with surface x-ray scattering techniques. By exposing the Liquid-metal surface at room temperature to doses on the order of 180 L of oxygen where 1 L = 10(-6) Torr s, a gallium oxide film with a well-defined thickness of similar to 5 Angstrom readily forms. The oxide thickness and roughness of the liquid/oxide and oxide/vapor interfaces do not change with oxygen dosage up to 1600 L nor with temperature up to 573 K. This is in contrast to what is observed for the bare liquid-Ga surface, which is roughened significantly by thermally excited capillary waves with temperatures up to only 443 K. This is a good indication that the oxide layer provides rigidity to the liquid surface and is likely a solid; grazing-incidence measurements suggest that the film is amorphous or poorly crystallized. Based on comparisons with known crystal structures, models are suggested for the atomic arrangements in the gallium oxide layer and its interface with the underlying liquid. C1 HARVARD UNIV,DIV ENGN & APPL SCI,CAMBRIDGE,MA 02138. HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. BAR ILAN UNIV,DEPT PHYS,IL-52100 RAMAT GAN,ISRAEL. NR 23 TC 99 Z9 100 U1 2 U2 26 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10786 EP 10790 DI 10.1103/PhysRevB.55.10786 PG 5 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300084 ER PT J AU Huff, WRA Chen, Y Zhang, XS Terminello, LJ Tao, FM Pan, YK Kellar, SA Moler, EJ Hussain, Z Wu, H Zheng, Y Zhou, X vonWittenau, AES Kim, S Huang, ZQ Yang, ZZ Shirley, DA AF Huff, WRA Chen, Y Zhang, XS Terminello, LJ Tao, FM Pan, YK Kellar, SA Moler, EJ Hussain, Z Wu, H Zheng, Y Zhou, X vonWittenau, AES Kim, S Huang, ZQ Yang, ZZ Shirley, DA TI Structure determination of chemisorbed c(2x2)P/Fe(100) using angle-resolved photoemission extended fine structure and self-consistent-field X alpha scattered-wave calculations: Comparison with c(2x2)S/Fe(100) SO PHYSICAL REVIEW B LA English DT Article ID ONE-ELECTRON PROPERTIES; PHOTOELECTRON DIFFRACTION; MAGNETIC-PROPERTIES; ADSORBATE-GEOMETRY; GRAIN-BOUNDARY; SURFACE; PHOSPHORUS; IRON; FE(001); SULFUR AB Angle-resolved photoemission extended fine structure (ARPEFS) was used to determine the structure of c(2 x 2)P/Fe(100). Photoemission data were collected normal to the (100) surface and 45 degrees off-normal along the [011] direction at room temperature. A close analysis of the autoregressive linear-prediction-based Fourier transform indicates that the P atoms adsorb in the high-coordination fourfold hollow sites. Curved-wave multiple-scattering calculations confirmed the fourfold hollow adsorption site. The P atoms were determined to bond 1.02 Angstrom above the first layer of Fe atoms and the Fe-P-Fe bond angle is 140.6 degrees. Additionally, it was determined that there was no expansion of the Fe surface. Self-consistent-field X alpha scattered-wave calculations were performed for the c(2 x 2)P/Fe(100) and the c(2 x 2)S/Fe(100) systems. These independent results are in excellent agreement with this P/Fe structure and the S/Fe structure previously published, confirming the ARPEFS determination that the Fe-1-Fe-2 interlayer spacing is contracted from the bulk value for S/Fe but not for P/Fe. Finally, this structure is compared to structures from the literature of atomic nitrogen, atomic oxygen, and sulfur adsorbed on the Fe(100) surface. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. PENN STATE UNIV,DEPT CHEM & PHYS,UNIVERSITY PK,PA 16802. ZHEJIANG UNIV,DEPT PHYS,HANGZHOU 310027,PEOPLES R CHINA. BOSTON COLL,DEPT CHEM,CHESTNUT HILL,MA 02167. UNIV HONG KONG,DEPT PHYS,HONG KONG,HONG KONG. OPLINK,SAN JOSE,CA 95131. KOREA INST TECHNOL,CHOONGCHUNGNAM DO 30031,SOUTH KOREA. UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. JILIN UNIV,INST THEORET CHEM,CHANGCHUN,PEOPLES R CHINA. RP Huff, WRA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Kim, Sehun/C-1972-2011 NR 53 TC 7 Z9 7 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10830 EP 10840 DI 10.1103/PhysRevB.55.10830 PG 11 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300090 ER PT J AU Wu, CJ Klepeis, JE AF Wu, CJ Klepeis, JE TI Halogen adsorption on transition-metal surfaces: A case study of Cl on Ta(110) SO PHYSICAL REVIEW B LA English DT Article ID TA(100) AB Through a series of ab initio calculations, we not only predict the atomic and electronic structure of CI on Ta(110), but also provide a quantitative basis for understanding a number of controversial questions regarding halogen adsorption on transition-metal surfaces. We demonstrate that a simple dipole layer model accurately describes the unexpected decrease in the work function upon halogen absorption, and that our proposed overlayer structure explains the one-dimensional streaking in the low-energy electron-diffraction pattern of the adsorbate-covered surface. An analysis of the electronic structure suggests that transition metals such as Ta look like simple metals from the point of view of highly electronegative adsorbates such as Cl. RP Wu, CJ (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551, USA. NR 22 TC 11 Z9 11 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1997 VL 55 IS 16 BP 10848 EP 10853 DI 10.1103/PhysRevB.55.10848 PG 6 WC Physics, Condensed Matter SC Physics GA WW803 UT WOS:A1997WW80300092 ER PT J AU Sigl, G Olinto, AV Jedamzik, K AF Sigl, G Olinto, AV Jedamzik, K TI Primordial magnetic fields from cosmological first order phase transitions SO PHYSICAL REVIEW D LA English DT Article ID EARLY UNIVERSE; ELECTROWEAK; NUCLEOSYNTHESIS; FLUCTUATIONS; INSTABILITY; EVOLUTION; BUBBLES; QCD; BARYOGENESIS; GROWTH AB We give an improved estimate of primordial magnetic fields generated during cosmological first order phase transitions. We examine the charge distribution at the nucleated bubble wall and its dynamics. We consider instabilities on the bubble walls developing during the phase transition. It is found that damping of these instabilities due to viscosity and heat conductivity caused by particle diffusion can be important in the QCD phase transition, but is probably negligible in the electroweak transition. We show how such instabilities together with the surface charge densities on bubble walls excite magnetic fields within a certain range of wavelengths. We discuss how these magnetic seed fields may be amplified by magneto hydrodynamics effects in the turbulent fluid. The strength and spectrum of the primordial magnetic field at the present time for the cases where this mechanism was operative during the electroweak or the QCD phase transition are estimated. On a 10 Mpc comoving scale, field strengths of the order 10(-29) G for electroweak and 10(-20) G for QCD, could be attained for reasonable phase transition parameters. C1 NASA, FERMILAB ASTROPHYS CTR, FERMI NATL ACCELERATOR LAB, BATAVIA, IL 60501 USA. LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RP Sigl, G (reprint author), UNIV CHICAGO, ENRICO FERMI INST, DEPT ASTRON & ASTROPHYS, CHICAGO, IL 60637 USA. OI Sigl, Guenter/0000-0002-4396-645X NR 45 TC 145 Z9 145 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 APR 15 PY 1997 VL 55 IS 8 BP 4582 EP 4590 DI 10.1103/PhysRevD.55.4582 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV250 UT WOS:A1997WV25000012 ER PT J AU Antoniadis, I Mazur, PO Mottola, E AF Antoniadis, I Mazur, PO Mottola, E TI Quantum diffeomorphisms and conformal symmetry SO PHYSICAL REVIEW D LA English DT Article ID DUAL STRING SPECTRUM; QUANTIZATION; GEOMETRY; GRAVITY; SECTOR AB We analyze the constraints of general coordinate invariance for quantum theories possessing conformal symmetry in four dimensions. The character of these constraints simplifies enormously on the Einstein universe RxS(3). The SO(4,2) global conformal symmetry algebra of this space determines uniquely a finite shift in the Hamiltonian constraint from its classical value. In other words, the global Wheeler-De Witt equation is modified at the quantum level in a well-defined way in this case. We argue that the higher moments of T-00 should not be imposed on the physical states a priori either, but only the weaker condition [<(T)over dot (00)>] = 0. We present an explicit example of the quantization and diffeomorphism constraints on RxS(3) for a free conformal scalar field. C1 UNIV S CAROLINA,DEPT PHYS & ASTRON,COLUMBIA,SC 29208. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Antoniadis, I (reprint author), ECOLE POLYTECH,CTR PHYS THEOR,F-91128 PALAISEAU,FRANCE. OI Mazur, Pawel/0000-0002-1679-3637 NR 21 TC 24 Z9 24 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1997 VL 55 IS 8 BP 4756 EP 4769 DI 10.1103/PhysRevD.55.4756 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV250 UT WOS:A1997WV25000028 ER PT J AU Antoniadis, I Mazur, PO Mottola, E AF Antoniadis, I Mazur, PO Mottola, E TI Physical states of the quantum conformal factor SO PHYSICAL REVIEW D LA English DT Article ID DUAL STRING SPECTRUM; SITTER SPACE; QUANTIZATION; GEOMETRY; FIELD; GRAVITY AB The conformal factor of the spacetime metric becomes dynamical due to the trace anomaly of matter fields. Its dynamics is described by an effective action which we quantize by canonical methods on the Einstein universe RxS(3). We find an infinite tower of discrete stales which satisfy the constraints or quantum diffeomorphism invariance. These physical states are in one-to-one correspondence with operators constructed by integrating integer powers of the Ricci scalar. C1 UNIV S CAROLINA,DEPT PHYS & ASTRON,COLUMBIA,SC 29208. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Antoniadis, I (reprint author), ECOLE POLYTECH,CTR PHYS THEOR,F-91128 PALAISEAU,FRANCE. OI Mazur, Pawel/0000-0002-1679-3637 NR 26 TC 39 Z9 39 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 APR 15 PY 1997 VL 55 IS 8 BP 4770 EP 4784 DI 10.1103/PhysRevD.55.4770 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV250 UT WOS:A1997WV25000029 ER PT J AU Saririan, K AF Saririan, K TI Gaugino condensation with S duality and field-theoretical threshold corrections SO PHYSICAL REVIEW D LA English DT Article ID STRING THEORY; SUPERSYMMETRY BREAKING; LINEAR MULTIPLET; COUPLINGS; SUPERGRAVITY; UNIFICATION; ANOMALIES; MODELS; CANCELLATION; CONSTRAINTS AB We study gaugino condensation in the presence of an intermediate mass scale in the hidden sector. S duality is imposed as an approximate symmetry of the effective supergravity theory. Furthermore, we include in the Kahler potential the renormalization of the gauge coupling and the one-loop threshold corrections at the intermediate scale. It is shown that confinement is indeed achieved. Furthermore, a new running behavior of the dilaton arises which we attribute to S duality. We also discuss the effects of the intermediate scale, and possible phenomenological implications of this model. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP Saririan, K (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720, USA. NR 43 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD APR 15 PY 1997 VL 55 IS 8 BP 4839 EP 4847 DI 10.1103/PhysRevD.55.4839 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA WV250 UT WOS:A1997WV25000035 ER PT J AU Li, H Dunn, JJ Luft, BJ Lawson, CL AF Li, H Dunn, JJ Luft, BJ Lawson, CL TI Crystal structure of Lyme disease antigen outer surface protein A complexed with an Fab SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ANTIBODY-BINDING DOMAINS; BORRELIA-BURGDORFERI; MEMBRANE-PROTEINS; A OSPA; MOLECULAR REPLACEMENT; POLAR ZIPPERS; SPIROCHETE; INFECTION; IMMUNITY; AGENT AB OspA (outer surface protein A) is an abundant immunogenic lipoprotein of the Lyme disease spirochete Borrelia burgdorferi. The crystal structure of a soluble recombinant form of OspA was solved in a complex with the Fab fragment of mouse monoclonal antibody 184.1 and refined to a resolution of 1.9 Angstrom. OspA has a repetitive antiparallel beta topology with an unusual nonglobular region of ''freestanding'' sheet connecting globular N- and C-terminal domains. Arrays of residues with alternating charges are a predominant feature of the folding pattern in the nonglobular region. The 184.1 epitope overlaps with a well conserved surface in the N-terminal domain, and a hydrophobic cavity buried in a positively charged cleft in the C-terminal domain is a potential binding site for an unknown ligand. An exposed variable region on the C terminal domain of OspA is predicted to be an important factor in the worldwide effectiveness of OspA-based vaccines. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. SUNY STONY BROOK,SCH MED,DIV INFECT DIS,STONY BROOK,NY 11794. OI Luft, Benjamin/0000-0001-9008-7004 FU NIAID NIH HHS [R01-AI37256] NR 54 TC 120 Z9 123 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1997 VL 94 IS 8 BP 3584 EP 3589 DI 10.1073/pnas.94.8.3584 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WW810 UT WOS:A1997WW81000021 PM 9108020 ER PT J AU Gilmanshin, R Williams, S Callender, RH Woodruff, WH Dyer, RB AF Gilmanshin, R Williams, S Callender, RH Woodruff, WH Dyer, RB TI Fast events in protein folding: Relaxation dynamics of secondary and tertiary structure in native apomyoglobin SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MOLTEN GLOBULE INTERMEDIATE; INFRARED-SPECTROSCOPY; PEPTIDES; MYOGLOBIN AB We report the fast relaxation dynamics of ''native'' apomyoglobin (pH 5.3) following a 10-ns, laser-induced temperature jump. The structural dynamics are probed using time-resolved infrared spectroscopy. The infrared kinetics monitored within the amide I absorbance of the polypeptide backbone exhibit two distinct relaxation phases which have different spectral signatures and occur on very different time scales (nu = 1633 cm(-1) 48 ns; nu = 1650 cm-1, tau = 132 mu s). We assign these two spectral components to discrete substructures in the protein: helical structure that is solvated (1633 cm(-1)) and native helix that is protected from solvation by interhelix tertiary interactions (1650 cm(-1)). Folding rate coefficients inferred from the observed relaxations at 60 degrees C are k(f(solvated)) = (7 to 20) x 10(6) s(-1) and k(f(native)) = 3.6 x 10(3) s(-1), respectively. The faster rate is interpreted as the intrinsic rate of solvated helix formation, whereas the slower rate is interpreted as the rate of formation of tertiary contacts that determine a native helix. Thus, at 60 degrees C helix formation precedes the formation of tertiary structure by over three orders of magnitude in this protein. Furthermore, the distinct thermodynamics and kinetics observed for the apomyoglobin substructures suggest that they fold independently, or quasi-independently. The observation of inhomogeneous folding for apomyoglobin is remarkable, given the relatively small size and structural simplicity of this protein. C1 LOS ALAMOS NATL LAB,CST 4,LOS ALAMOS,NM 87545. CUNY CITY COLL,DEPT PHYS,NEW YORK,NY 10031. PHILLIPS LAB,GEOPHYS DIRECTORATE,HANSCOM AFB,MA 01731. FU NIGMS NIH HHS [GM45807, GM53640, R01 GM053640] NR 34 TC 184 Z9 186 U1 2 U2 24 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD APR 15 PY 1997 VL 94 IS 8 BP 3709 EP 3713 DI 10.1073/pnas.94.8.3709 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA WW810 UT WOS:A1997WW81000043 PM 9108042 ER PT J AU Deevi, SC Sikka, VK Inkson, BJ Cahn, RW AF Deevi, SC Sikka, VK Inkson, BJ Cahn, RW TI Effect of boron on the vacancy hardening of FeAl SO SCRIPTA MATERIALIA LA English DT Article ID DOPED FEAL; PERCENT AL; FRACTURE; HARDNESS; BEHAVIOR C1 UNIV CAMBRIDGE, DEPT MAT SCI & ENGN, CAMBRIDGE CB2 3QZ, ENGLAND. PHILIP MORRIS INC, RES CTR, RICHMOND, VA 23112 USA. RP Deevi, SC (reprint author), OAK RIDGE NATL LAB, DIV MET & CERAM, POB 2008, OAK RIDGE, TN 37831 USA. NR 16 TC 14 Z9 14 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD APR 15 PY 1997 VL 36 IS 8 BP 899 EP 904 DI 10.1016/S1359-6462(96)00497-6 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA WQ460 UT WOS:A1997WQ46000009 ER PT J AU Woodworth, JR Aragon, BP Hamilton, TW AF Woodworth, JR Aragon, BP Hamilton, TW TI Effect of bumps on the wafer on ion distribution functions in high-density argon and argon-chlorine discharges SO APPLIED PHYSICS LETTERS LA English DT Article ID REFERENCE CELL; ELECTRONICS AB The presence of bumps on or near the wafer in plasma processing reactors can significantly affect plasma parameters. We have used a gridded energy analyzer to measure ion fluxes, energy distributions, and angular distributions near such bumps on a grounded electrode in an inductively coupled discharge in a Gaseous Electronics Conference Reference Cell. We find that the bumps affect the ion energy distributions only slightly, lower the ion fluxes by more than a factor of 2 and dramatically alter the ion angular distributions. (C) 1997 American Institute of Physics. C1 APPL PHYS INT,ALBUQUERQUE,NM 87110. RP Woodworth, JR (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 4 TC 19 Z9 19 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 14 PY 1997 VL 70 IS 15 BP 1947 EP 1949 DI 10.1063/1.118814 PG 3 WC Physics, Applied SC Physics GA WT573 UT WOS:A1997WT57300010 ER PT J AU Missert, N Friedmann, TA Sullivan, JP Copeland, RG AF Missert, N Friedmann, TA Sullivan, JP Copeland, RG TI Characterization of electron emission from planar amorphous carbon thin films using in situ scanning electron microscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID CVD DIAMOND FILMS; FIELD-EMISSION AB Electron emission characteristics combined with in situ scanning electron microscope images have been measured on a series of amorphous carbon films grown by pulsed laser deposition. Uniform, reproducible current-voltage characteristics without morphological damage are only observed with sequential voltage ramps less than or equal to 5 V/s for anode-cathode gaps of 10-200 mu m. The field threshold and emission barrier increase with laser energy density used during film growth. This dependence of emission parameters on film growth conditions appears to be correlated with the presence of conducting filaments extending through the film thickness. (C) 1997 American Institute of Physics. RP Missert, N (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 22 TC 50 Z9 51 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 14 PY 1997 VL 70 IS 15 BP 1995 EP 1997 DI 10.1063/1.119078 PG 3 WC Physics, Applied SC Physics GA WT573 UT WOS:A1997WT57300026 ER PT J AU Warren, WL Pike, GE Tuttle, BA Dimos, D AF Warren, WL Pike, GE Tuttle, BA Dimos, D TI Polarization-induced trapped charge in ferroelectrics SO APPLIED PHYSICS LETTERS LA English DT Article ID PHOTOINDUCED HYSTERESIS CHANGES; THIN-FILMS; DIELECTRICS; DEGRADATION; CERAMICS; BIAS AB We have examined the nature of the defects in BaTiO3 capacitors that have been subjected to an electric field at elevated temperatures (an accelerated aging process) using thermally stimulated current (TSC) and electron paramagnetic resonance measurements. The accelerated aging stress causes the ferroelectric capacitor to exhibit a reduction in its insulating resistance and a voltage offset in its polarization-voltage hysteresis loop. Following the accelerated aging treatment, the trapped charge estimates obtained from the TSC and the hysteresis measurements (as ascertained from the voltage offset) differ significantly and are attributed to either local charge compensation or uniform charge trapping within the dielectric. We also show that some of the trapped charge in ferroelectric materials is directly associated with the net polarization. (C) 1997 American Institute of Physics. RP Warren, WL (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 16 TC 29 Z9 29 U1 1 U2 16 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 14 PY 1997 VL 70 IS 15 BP 2010 EP 2012 DI 10.1063/1.118805 PG 3 WC Physics, Applied SC Physics GA WT573 UT WOS:A1997WT57300031 ER PT J AU Dantsker, E Tanaka, S Clarke, J AF Dantsker, E Tanaka, S Clarke, J TI High-T-c super conducting quantum interference devices with slots or holes: Low 1/f noise in ambient magnetic fields SO APPLIED PHYSICS LETTERS LA English DT Article ID FLUX NOISE; SQUID AB High-transition temperature de superconducting quantum interference devices (SQUIDs) have been fabricated with arrays of slots or holes patterned in the 186x204 mu m(2) washers. In two designs, with seven slots or 248 holes, the linewidth of the remaining YBa2Cu3O7-x, film was 4 mu m. These devices exhibited virtually no increase in their low-frequency noise when they were cooled in static magnetic fields up to a certain threshold, above 100 mu T in the best case. Furthermore, the mutual inductance between these devices and a seven-turn, spiral coil was at least 85% of that for a solid SQUID with the same outer dimensions. (C) 1997 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Dantsker, E (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 12 TC 131 Z9 131 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 14 PY 1997 VL 70 IS 15 BP 2037 EP 2039 DI 10.1063/1.118776 PG 3 WC Physics, Applied SC Physics GA WT573 UT WOS:A1997WT57300040 ER PT J AU Chatterjee, A Takada, E Torikoshi, M Kanazawa, M AF Chatterjee, A Takada, E Torikoshi, M Kanazawa, M TI Diagnostic imaging by energetic radioactive particle beams: Applications in Bragg Peak cancer therapy SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Radioactive Nuclear Beams CY JUN 03-07, 1996 CL OMIYA, JAPAN SP Inst Phys & Chem Res, Inst Nucl Study, Univ Tokyo, Int Union Pure & Appl Phys C1 NATL INST RADIOL SCI,DIV ACCELERATOR PHYS & ENGN,INAGE KU,CHIBA 263,JAPAN. RP Chatterjee, A (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720, USA. NR 7 TC 3 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 14 PY 1997 VL 616 IS 1-2 BP C478 EP C489 PG 12 WC Physics, Nuclear SC Physics GA WU295 UT WOS:A1997WU29500055 PM 11540336 ER PT J AU Garrett, JD AF Garrett, JD TI The latest from the new Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Radioactive Nuclear Beams CY JUN 03-07, 1996 CL OMIYA, JAPAN SP Inst Phys & Chem Res, Inst Nucl Study, Univ Tokyo, Int Union Pure & Appl Phys AB The status of the new Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory (ORNL), which is slated to start its scientific program late in 1996 is discussed, as is the new experimental equipment which is being constructed at this facility. Information on the early scientific program is also given. RP Garrett, JD (reprint author), OAK RIDGE NATL LAB,DIV PHYS,MAIL STOP 4348,OAK RIDGE,TN 37831, USA. NR 11 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 14 PY 1997 VL 616 IS 1-2 BP C3 EP C10 PG 8 WC Physics, Nuclear SC Physics GA WU295 UT WOS:A1997WU29500004 ER PT J AU Haustein, PE AF Haustein, PE TI Application of ISOL-type radioactive nuclear beams in the physical, biomedical and environmental sciences SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Radioactive Nuclear Beams CY JUN 03-07, 1996 CL OMIYA, JAPAN SP Inst Phys & Chem Res, Inst Nucl Study, Univ Tokyo, Int Union Pure & Appl Phys AB ISOL-type radioactive nuclear beam facilities can provide a wide spectrum of low energy isotopic beams at the isotope/mass separator stage. These beams have the potential to promote significant expansion for applications of radioactivity in diverse areas of basic or applied research. Examples in the physical, biomedical and environmental sciences are presented. RP Haustein, PE (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,BLDG 555A,UPTON,NY 11973, USA. NR 9 TC 2 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 14 PY 1997 VL 616 IS 1-2 BP C469 EP C477 PG 9 WC Physics, Nuclear SC Physics GA WU295 UT WOS:A1997WU29500054 ER PT J AU Mittig, W Chartier, M Angelique, JC Audi, G Casandjian, JM Cunsolo, A Donzaud, C Chabert, M Ferme, J Fifield, LK Foti, A Gillibert, A LepineSzily, A Lewitowicz, M Lukyanov, S MacCormick, M Morrissey, DJ Moscatello, MH Odland, OH Orr, NA Ostrowski, A Politi, G Spitaels, C Sherrill, BM Stephan, C Suomijarvi, T TassanGot, L Vieira, DJ Villari, ACC Wouters, JM AF Mittig, W Chartier, M Angelique, JC Audi, G Casandjian, JM Cunsolo, A Donzaud, C Chabert, M Ferme, J Fifield, LK Foti, A Gillibert, A LepineSzily, A Lewitowicz, M Lukyanov, S MacCormick, M Morrissey, DJ Moscatello, MH Odland, OH Orr, NA Ostrowski, A Politi, G Spitaels, C Sherrill, BM Stephan, C Suomijarvi, T TassanGot, L Vieira, DJ Villari, ACC Wouters, JM TI Mass measurements near N=Z SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Radioactive Nuclear Beams CY JUN 03-07, 1996 CL OMIYA, JAPAN SP Inst Phys & Chem Res, Inst Nucl Study, Univ Tokyo, Int Union Pure & Appl Phys ID LIGHT-NUCLEI; RICH NUCLEI; BETA-DECAY; ISOTOPES; SPECTROMETER; SN-100; FRAGMENTATION; LINE AB After an outline of the physics motivations, that illustrate why we think it is important to measure masses in the region N approximate to Z, we report on on experiments performed at Ganil. An experiment aimed at measuring the masses of proton-rich nuclei in the mass region A approximate to 60-80 has been performed, using a direct time-of-flight technique in conjunction with SISSI and the SPEG spectrometer at GANIL. The nuclei were produced via the fragmentation of a Kr-78 beam (73 MeV/nucleon). A novel technique for the purification of the secondary beams, based on the stripping of the ions and using the alpha and the SPEG spectrometers, was succesfully checked. It allows for good selectivity without altering the beam quality. Secondary ions of Ag-100, Cd-100, In-100 and Sn-100 were produced via the fusion-evaporation reaction Cr-50 + Ni-58 at an energy of 5.1 MeV/nucleon, and were accelerated simultaneously in the second cyclotron of GANIL (CSS2). About 10 counts were observed from the production and acceleration of Sn-100(22+). The masses of Cd-100, In-100 and Sn-100 were measured with respect to Ag-100 using the CSS2 cyclotron, with precisions of 2 x 10(-6), 3 x 10(-6) and 10(-5) respectively. C1 INST SCI MAT & RAYONNEMENT,LPC,F-14050 CAEN,FRANCE. CTR SPECTROMETRIE NUCL & SPECTROMETRIE MASSE,F-91406 ORSAY,FRANCE. IST NAZL FIS NUCL,I-95129 CATANIA,ITALY. INST PHYS NUCL,F-91406 ORSAY,FRANCE. UNIV SAO PAULO,IFUSP,BR-14098 SAO PAULO,BRAZIL. JOINT INST NUCL RES DUBNA,LNR,DUBNA 101000,MOSCOW REGION,RUSSIA. MICHIGAN STATE UNIV,NSCL,E LANSING,MI 48824. LANL,LOS ALAMOS,NM 87545. AUSTRALIAN NATL UNIV,DEPT PHYS NUCL,RSPHYSE,CANBERRA,ACT 0200,AUSTRALIA. CNE SACLAY,CEA,DSM,DAPNIA,SPHN,F-91191 GIF SUR YVETTE,FRANCE. UNIV CATANIA,DIP FIS,I-95125 CATANIA,ITALY. UNIV BERGEN,INST FYS,N-5007 BERGEN,NORWAY. RP Mittig, W (reprint author), GANIL,BLD HENRI BECQUEREL,BP 5027,F-14021 CAEN,FRANCE. RI Sherrill, Bradley/B-4098-2009; Sherrill, Bradley/B-3378-2011; Lepine-Szily , Alinka/I-3325-2012 OI Lepine-Szily , Alinka/0000-0001-6640-8824 NR 37 TC 7 Z9 7 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 14 PY 1997 VL 616 IS 1-2 BP C329 EP C340 PG 12 WC Physics, Nuclear SC Physics GA WU295 UT WOS:A1997WU29500040 ER PT J AU Rehm, KE Paul, M Roberts, AD Jiang, CL Blumenthal, D Davids, CN DeCrock, P Fischer, SM Gehring, J Henderson, D Lister, CJ Nickles, J Nolen, J Pardo, RC Schiffer, JP Segel, RE AF Rehm, KE Paul, M Roberts, AD Jiang, CL Blumenthal, D Davids, CN DeCrock, P Fischer, SM Gehring, J Henderson, D Lister, CJ Nickles, J Nolen, J Pardo, RC Schiffer, JP Segel, RE TI Nuclear reaction studies with radioactive F-18 beams at ATLAS SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT 4th International Conference on Radioactive Nuclear Beams CY JUN 03-07, 1996 CL OMIYA, JAPAN SP Inst Phys & Chem Res, Inst Nucl Study, Univ Tokyo, Int Union Pure & Appl Phys ID F-18(P,ALPHA)O-15 REACTION AB The contribution of the F-18(p,gamma) reaction to the production of Ne-19 which is the crucial isotope for the breakout from the hot CNO cycle into the rp process, has been investigated in experiments with F-18 beams. Measurements of the cross sections for the F-18(p,alpha)O-15 and the F-18(p,gamma)Ne-19 reactions indicate that the contribution from the (p,gamma) route to the formation of Ne-19 is small. C1 HEBREW UNIV JERUSALEM,JERUSALEM,ISRAEL. UNIV WISCONSIN,MADISON,WI. NORTHWESTERN UNIV,EVANSTON,IL. RP Rehm, KE (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 17 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD APR 14 PY 1997 VL 616 IS 1-2 BP C115 EP C122 PG 8 WC Physics, Nuclear SC Physics GA WU295 UT WOS:A1997WU29500016 ER PT J AU Abe, F Akimoto, H Akopian, A Albrow, MG Amendolia, SR Amidei, D Antos, J AnwayWiese, C Aota, S Apollinari, G Asakawa, T Ashmanskas, W Atac, M Azfar, F AzziBacchetta, P Bacchetta, N Badgett, W Bagdasarov, S Bailey, MW Bao, J DeBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Barone, M Barzi, E Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bevensee, B Bhatti, A Biery, K Binkley, M Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bolla, G Bortoletto, D Boudreau, J Breccia, L Bromberg, C Bruner, N BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cauz, D Cen, Y Cervelli, F Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D CroninHennessy, D Culbertson, R Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Dunn, A Eddy, N Enisweiler, K Elias, JE Ely, R Engels, E Errede, D Errede, S Fan, Q Feild, G Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fuess, TA Fukui, Y Funaki, S Galeotti, S Gallinaro, M Ganel, O GarciaSciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Groer, L GrossoPilcher, C Guillian, G Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handler, R Hans, RM Happacher, F Hara, K Hardman, AD Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Hayashi, E Heinrich, J Hoffman, KD Hohlmann, M Holck, C Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Huston, J Huth, J Hylen, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y Jensen, H Joshi, U Kadel, RW Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Keeble, L Kelley, K Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kharadia, B Kim, BJ Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Korytov, A Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuwabara, T Kuhlmann, SE Kuns, E Laasanen, AT Lammel, S Lamoureux, JI LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Long, O Loomis, C Loreti, M Lu, J Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Mitsushio, H Miyamoto, T Miyashita, S Moggi, N Morita, Y Mueller, J Mukherjee, A Muller, T Murat, P Nakada, H Nakano, I Nelson, C Neuberger, D NewmanHolmes, C Ngan, CY Ninomiya, M Nodulman, L Oh, SH Ohl, KE Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Oliveira, R Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Park, S Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Ribon, A Rimondi, F Ristori, L Robertson, WJ Rodrigo, T Rolli, S Romano, J Rosenson, L Roser, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Shapiro, M Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Snider, FD Song, T Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Strohmer, R Stuart, D Sullivan, G Soumarokov, A Sumorok, K Suzuki, J Takada, T Takahashi, T Takano, T Takikawa, K Tamura, N Tannenbaum, B Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A DeTroconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Uemura, N Ukegawa, F Unal, G Valls, J VandenBrink, S Vejcik, S Velev, G Vidal, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, J Wang, MJ Wang, QF Warburton, A Watts, T Webb, R Wei, C Wendt, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yu, L Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, W Zucchelli, S AF Abe, F Akimoto, H Akopian, A Albrow, MG Amendolia, SR Amidei, D Antos, J AnwayWiese, C Aota, S Apollinari, G Asakawa, T Ashmanskas, W Atac, M Azfar, F AzziBacchetta, P Bacchetta, N Badgett, W Bagdasarov, S Bailey, MW Bao, J DeBarbaro, P BarbaroGaltieri, A Barnes, VE Barnett, BA Barone, M Barzi, E Bauer, G Baumann, T Bedeschi, F Behrends, S Belforte, S Bellettini, G Bellinger, J Benjamin, D Benlloch, J Bensinger, J Benton, D Beretvas, A Berge, JP Berryhill, J Bertolucci, S Bevensee, B Bhatti, A Biery, K Binkley, M Bisello, D Blair, RE Blocker, C Bodek, A Bokhari, W Bolognesi, V Bolla, G Bortoletto, D Boudreau, J Breccia, L Bromberg, C Bruner, N BuckleyGeer, E Budd, HS Burkett, K Busetto, G ByonWagner, A Byrum, KL Cammerata, J Campagnari, C Campbell, M Caner, A Carithers, W Carlsmith, D Castro, A Cauz, D Cen, Y Cervelli, F Chang, PS Chang, PT Chao, HY Chapman, J Cheng, MT Chiarelli, G Chikamatsu, T Chiou, CN Christofek, L Cihangir, S Clark, AG Cobal, M Cocca, E Contreras, M Conway, J Cooper, J Cordelli, M Couyoumtzelis, C Crane, D CroninHennessy, D Culbertson, R Daniels, T DeJongh, F Delchamps, S DellAgnello, S DellOrso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Dunn, A Eddy, N Enisweiler, K Elias, JE Ely, R Engels, E Errede, D Errede, S Fan, Q Feild, G Ferretti, C Fiori, I Flaugher, B Foster, GW Franklin, M Frautschi, M Freeman, J Friedman, J Frisch, H Fuess, TA Fukui, Y Funaki, S Galeotti, S Gallinaro, M Ganel, O GarciaSciveres, M Garfinkel, AF Gay, C Geer, S Gerdes, DW Giannetti, P Giokaris, N Giromini, P Giusti, G Gladney, L Glenzinski, D Gold, M Gonzalez, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Grassmann, H Groer, L GrossoPilcher, C Guillian, G Guo, RS Haber, C Hafen, E Hahn, SR Hamilton, R Handler, R Hans, RM Happacher, F Hara, K Hardman, AD Harral, B Harris, RM Hauger, SA Hauser, J Hawk, C Hayashi, E Heinrich, J Hoffman, KD Hohlmann, M Holck, C Hollebeek, R Holloway, L Holscher, A Hong, S Houk, G Hu, P Huffman, BT Hughes, R Huston, J Huth, J Hylen, J Ikeda, H Incagli, M Incandela, J Introzzi, G Iwai, J Iwata, Y Jensen, H Joshi, U Kadel, RW Kajfasz, E Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Keeble, L Kelley, K Kennedy, RD Kephart, R Kesten, P Kestenbaum, D Keup, RM Keutelian, H Keyvan, F Kharadia, B Kim, BJ Kim, DH Kim, HS Kim, SB Kim, SH Kim, YK Kirsch, L Koehn, P Kondo, K Konigsberg, J Kopp, S Kordas, K Korytov, A Koska, W Kovacs, E Kowald, W Krasberg, M Kroll, J Kruse, M Kuwabara, T Kuhlmann, SE Kuns, E Laasanen, AT Lammel, S Lamoureux, JI LeCompte, T Leone, S Lewis, JD Limon, P Lindgren, M Liss, TM Lockyer, N Long, O Loomis, C Loreti, M Lu, J Lucchesi, D Lukens, P Lusin, S Lys, J Maeshima, K Maghakian, A Maksimovic, P Mangano, M Mansour, J Mariotti, M Marriner, JP Martin, A Matthews, JAJ Mattingly, R McIntyre, P Melese, P Menzione, A Meschi, E Metzler, S Miao, C Miao, T Michail, G Miller, R Minato, H Miscetti, S Mishina, M Mitsushio, H Miyamoto, T Miyashita, S Moggi, N Morita, Y Mueller, J Mukherjee, A Muller, T Murat, P Nakada, H Nakano, I Nelson, C Neuberger, D NewmanHolmes, C Ngan, CY Ninomiya, M Nodulman, L Oh, SH Ohl, KE Ohmoto, T Ohsugi, T Oishi, R Okabe, M Okusawa, T Oliveira, R Olsen, J Pagliarone, C Paoletti, R Papadimitriou, V Pappas, SP Parashar, N Park, S Parri, A Patrick, J Pauletta, G Paulini, M Perazzo, A Pescara, L Peters, MD Phillips, TJ Piacentino, G Pillai, M Pitts, KT Plunkett, R Pondrom, L Proudfoot, J Ptohos, F Punzi, G Ragan, K Reher, D Ribon, A Rimondi, F Ristori, L Robertson, WJ Rodrigo, T Rolli, S Romano, J Rosenson, L Roser, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Schlabach, P Schmidt, EE Schmidt, MP Scribano, A Segler, S Seidel, S Seiya, Y Sganos, G Shapiro, M Shaw, NM Shen, Q Shepard, PF Shimojima, M Shochet, M Siegrist, J Sill, A Sinervo, P Singh, P Skarha, J Sliwa, K Snider, FD Song, T Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Stanco, L Steele, J Stefanini, A Strahl, K Strait, J Strohmer, R Stuart, D Sullivan, G Soumarokov, A Sumorok, K Suzuki, J Takada, T Takahashi, T Takano, T Takikawa, K Tamura, N Tannenbaum, B Tartarelli, F Taylor, W Teng, PK Teramoto, Y Tether, S Theriot, D Thomas, TL Thun, R Timko, M Tipton, P Titov, A Tkaczyk, S Toback, D Tollefson, K Tollestrup, A DeTroconiz, JF Truitt, S Tseng, J Turini, N Uchida, T Uemura, N Ukegawa, F Unal, G Valls, J VandenBrink, S Vejcik, S Velev, G Vidal, R Vondracek, M Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, J Wang, MJ Wang, QF Warburton, A Watts, T Webb, R Wei, C Wendt, C Wenzel, H Wester, WC Wicklund, AB Wicklund, E Wilkinson, R Williams, HH Wilson, P Winer, BL Winn, D Wolinski, D Wolinski, J Worm, S Wu, X Wyss, J Yagil, A Yao, W Yasuoka, K Ye, Y Yeh, GP Yeh, P Yin, M Yoh, J Yosef, C Yoshida, T Yovanovitch, D Yu, I Yu, L Yun, JC Zanetti, A Zetti, F Zhang, L Zhang, W Zucchelli, S TI Search for third generation leptoquarks in (p)over-bar-p collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID P(P)OVER-BAR COLLISIONS; SCALAR LEPTOQUARKS; HADRON COLLIDERS; Z0 DECAYS; DETECTOR; SYMMETRY; NUMBER; LIMITS AB We present the results of a search for third generation leptoquark (LQ) pairs in 110 +/- 8 pb(-1) of (p) over bar p collisions at root s = 1.8 TeV recorded by the Collider Detector at Fermilab. We assume third generation leptoquarks decay to a tau lepton and a b quark with branching ratio beta. We observe one candidate event, consistent with standard model background expectations. We place upper limits on sigma((p) over bar p --> LQ(<(LQ)over bar>).beta(2) as a function of the leptoquark mass M(LQ). We exclude at 95% confidence level scalar leptoquarks with M(LQ) < 99 GeV/c(2), gauge vector leptoquarks with M(LQ) < 225 GeV/c(2), and nongauge vector leptoquarks with M(LQ) < 170 GeV/c(2) for beta = 1. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV BOLOGNA,IST NAZL FIS NUCL,I-40126 BOLOGNA,ITALY. BRANDEIS UNIV,WALTHAM,MA 02254. UNIV CALIF LOS ANGELES,LOS ANGELES,CA 90024. UNIV CHICAGO,CHICAGO,IL 60637. DUKE UNIV,DURHAM,NC 27708. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. UNIV GENEVA,CH-1211 GENEVA 4,SWITZERLAND. HARVARD UNIV,CAMBRIDGE,MA 02138. HIROSHIMA UNIV,HIGASHIHIROSHIMA 724,JAPAN. UNIV ILLINOIS,URBANA,IL 61801. MCGILL UNIV,INST PARTICLE PHYS,MONTREAL,PQ H3A 2T8,CANADA. UNIV TORONTO,TORONTO,ON M5S 1A7,CANADA. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. ERNEST ORLANDO LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MICHIGAN,ANN ARBOR,MI 48109. MICHIGAN STATE UNIV,E LANSING,MI 48824. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. OHIO STATE UNIV,COLUMBUS,OH 43210. OSAKA CITY UNIV,OSAKA 588,JAPAN. UNIV PADUA,IST NAZL FIS NUCL,SEZ PADOVA,I-35131 PADUA,ITALY. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. UNIV PITTSBURGH,PITTSBURGH,PA 15260. PURDUE UNIV,W LAFAYETTE,IN 47907. UNIV ROCHESTER,ROCHESTER,NY 14627. ROCKEFELLER UNIV,NEW YORK,NY 10021. RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. ACAD SINICA,TAIPEI 11529,TAIWAN. TEXAS A&M UNIV,COLLEGE STN,TX 77843. TEXAS TECH UNIV,LUBBOCK,TX 79409. UNIV TSUKUBA,TSUKUBA,IBARAKI 305,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53706. YALE UNIV,NEW HAVEN,CT 06511. RP Abe, F (reprint author), NATL LAB HIGH ENERGY PHYS,KEK,TSUKUBA,IBARAKI 305,JAPAN. RI Vucinic, Dejan/C-2406-2008; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Warburton, Andreas/N-8028-2013; Kim, Soo-Bong/B-7061-2014; Paulini, Manfred/N-7794-2014; Introzzi, Gianluca/K-2497-2015 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Warburton, Andreas/0000-0002-2298-7315; Paulini, Manfred/0000-0002-6714-5787; Introzzi, Gianluca/0000-0002-1314-2580 NR 32 TC 59 Z9 59 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2906 EP 2911 DI 10.1103/PhysRevLett.78.2906 PG 6 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300010 ER PT J AU Romosan, A Arroyo, CG deBarbaro, L deBarbaro, P Bazarko, AO Bernstein, RH Bodek, A Bolton, T Budd, H Conrad, J Drucker, RB Harris, DA Johnson, RA Kim, JH King, BJ Kinnel, T Lamm, MJ Lefmann, WC Marsh, W McFarland, KS McNulty, C Mishra, SR Naples, D Quintas, PZ Sakumoto, WK Schellman, H Sciulli, FJ Seligman, WG Shaevitz, MH Smith, WH Spentzouris, P Stern, EG Vakili, M Yang, UK Yu, J AF Romosan, A Arroyo, CG deBarbaro, L deBarbaro, P Bazarko, AO Bernstein, RH Bodek, A Bolton, T Budd, H Conrad, J Drucker, RB Harris, DA Johnson, RA Kim, JH King, BJ Kinnel, T Lamm, MJ Lefmann, WC Marsh, W McFarland, KS McNulty, C Mishra, SR Naples, D Quintas, PZ Sakumoto, WK Schellman, H Sciulli, FJ Seligman, WG Shaevitz, MH Smith, WH Spentzouris, P Stern, EG Vakili, M Yang, UK Yu, J TI High statistics search for nu(mu)((nu)over-bar(mu))->nu(e)((nu)over-bar(e)) oscillations in the small mixing angle regime SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRINO AB Limits on nu(mu)(<(nu)over bar>(mu)) <----> nu(e)(<(nu)over bar>(e)) oscillations based on a statistical separation of nu(e)N charged current interactions in the CCFR detector al Fermilab are presented. Neutrino energies range from 30 to 600 GeV with a mean of 140 GeV, and nu(mu), flight lengths vary from 0.9 to 1.4 km. The result excludes oscillations in the region with sin(2) 2 alpha > 1.8 x 10(-3) for large Delta m(2) (>1000 eV(2)) and Delta m(2) > 1.6 eV(2) for sin(2) 2 alpha = 1. This result is the most stringent limit to date for Delta m(2) > 25 eV(2) and it excludes the high Delta m(2) oscillation region favored by the LSND experiment. The nu(mu)-to-nu(e) cross-section ratio was measured as a test of nu(mu)(<(nu)over bar>(mu) <----> nu(e) (<(nu)over bar>(e)) universality to be 1.026 +/- 0.025(stat) +/- 0.049(syst). C1 UNIV CINCINNATI,CINCINNATI,OH 45221. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. KANSAS STATE UNIV,MANHATTAN,KS 66506. NORTHWESTERN UNIV,EVANSTON,IL 60208. UNIV OREGON,EUGENE,OR 97403. UNIV ROCHESTER,ROCHESTER,NY 14627. UNIV WISCONSIN,MADISON,WI 53706. RP Romosan, A (reprint author), COLUMBIA UNIV,NEW YORK,NY 10027, USA. NR 14 TC 81 Z9 81 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2912 EP 2915 DI 10.1103/PhysRevLett.78.2912 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300011 ER PT J AU Barrette, J Bellwied, R Bennett, S Bersch, R BraunMunzinger, P Chang, WC Cleland, WE Cole, JD Cormier, TM David, G Dee, J Dietzsch, O Drigert, MW Gilbert, S Hall, JR Hemmick, TK Herrmann, N Hong, B Jiang, CL Johnson, SC Kwon, Y Lacasse, R Lukaszew, A Li, Q Ludlam, TW McCorkle, S Mark, SK Matheus, R Miskowiec, D OBrien, E Panitkin, S Piazza, T Pollack, M Pruneau, C Rao, MN Rosati, M daSilva, NC Sedykh, S Sonnadara, U Stachel, J Takagui, EM Trzaska, M Voloshin, S Vongpaseuth, T Wang, G Wessels, JP Woody, CL Xu, N Zhang, Y Zou, C AF Barrette, J Bellwied, R Bennett, S Bersch, R BraunMunzinger, P Chang, WC Cleland, WE Cole, JD Cormier, TM David, G Dee, J Dietzsch, O Drigert, MW Gilbert, S Hall, JR Hemmick, TK Herrmann, N Hong, B Jiang, CL Johnson, SC Kwon, Y Lacasse, R Lukaszew, A Li, Q Ludlam, TW McCorkle, S Mark, SK Matheus, R Miskowiec, D OBrien, E Panitkin, S Piazza, T Pollack, M Pruneau, C Rao, MN Rosati, M daSilva, NC Sedykh, S Sonnadara, U Stachel, J Takagui, EM Trzaska, M Voloshin, S Vongpaseuth, T Wang, G Wessels, JP Woody, CL Xu, N Zhang, Y Zou, C TI Two-pion correlations in Au+Au collisions at 10.8 GeV/c per nucleon SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-ION COLLISIONS; BOSE-EINSTEIN CORRELATIONS; CORRELATION STRENGTH; 2-PION CORRELATIONS; INTERFEROMETRY AB Two-particle correlation functions for positive and negative pions have been measured in Au + Au collisions at 10.8 GeV/c per nucleon. The data were analyzed using one-and three-dimensional correlation functions. From the results of the three-dimensional fit the phase space density of pions was calculated. It is consistent with local thermal equilibrium. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. GESELL SCHWERIONENFORSCH MBH,D-6100 DARMSTADT,GERMANY. IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. SUNY STONY BROOK,STONY BROOK,NY 11794. UNIV PITTSBURGH,PITTSBURGH,PA 15260. UNIV SAO PAULO,SAO PAULO,BRAZIL. WAYNE STATE UNIV,DETROIT,MI 48202. RP Barrette, J (reprint author), MCGILL UNIV,MONTREAL,PQ H3A 2T5,CANADA. RI Voloshin, Sergei/I-4122-2013; OI Sonnadara, Upul/0000-0001-7862-2537; Chang, Wen-Chen/0000-0002-1695-7830 NR 30 TC 48 Z9 48 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2916 EP 2919 DI 10.1103/PhysRevLett.78.2916 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300012 ER PT J AU Cocks, JFC Butler, PA Cann, KJ Greenlees, PT Jones, GD Asztalos, S Bhattacharyya, P Broda, R Clark, RM Deleplanque, MA Diamond, RM Fallon, P Fornal, B Jones, PM Julin, R Lauritsen, T Lee, IY Macchiavelli, AO MacLeod, RW Smith, JF Stephens, FS Zhang, CT AF Cocks, JFC Butler, PA Cann, KJ Greenlees, PT Jones, GD Asztalos, S Bhattacharyya, P Broda, R Clark, RM Deleplanque, MA Diamond, RM Fallon, P Fornal, B Jones, PM Julin, R Lauritsen, T Lee, IY Macchiavelli, AO MacLeod, RW Smith, JF Stephens, FS Zhang, CT TI Observation of octupole structures in radon and radium isotopes and their contrasting behavior at high spin SO PHYSICAL REVIEW LETTERS LA English DT Article ID E1 TRANSITIONS; NUCLEI; DEFORMATION; INSTABILITY; GAMMASPHERE; PARAMETERS; MOMENTS; SHAPES; RA-226 AB Multinucleon transfer reactions have been used, for the first time, to populate high-spin bands of alternating parity states in Rn-218,Rn-220,Rn-222 and Ra-222,Ra-224,Ra-226. The behavior of the angular momentum alignment with rotational frequency for the Rn isotopes is very different when compared with Ra and Th isotopes with N approximate to 134, indicating a transition from octupole vibrational to stable octupole deformation. Throughout the measured spin range the values of \D-0/Q(0)\ remain constant for Ra-222 and Ra-226 and have a very small value for Ra-224, suggesting that the charge and mass distributions are not affected appreciably by rotations. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. PURDUE UNIV,DEPT CHEM,W LAFAYETTE,IN 47907. INST NUCL PHYS,PL-31342 KRAKOW,POLAND. UNIV JYVASKYLA,DEPT PHYS,FIN-40351 JYVASKYLA,FINLAND. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. SUNY STONY BROOK,STONY BROOK,NY 11794. RP Cocks, JFC (reprint author), UNIV LIVERPOOL,OLIVER LODGE LAB,LIVERPOOL L69 3BX,MERSEYSIDE,ENGLAND. OI Butler, Peter/0000-0001-6080-9205 NR 28 TC 93 Z9 95 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2920 EP 2923 DI 10.1103/PhysRevLett.78.2920 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300013 ER PT J AU Synakowski, EJ Batha, SH Beer, MA Bell, MG Bell, RE Budny, RV Bush, CE Efthimion, PC Hammett, GW Hahm, TS LeBlanc, B Levinton, F Mazzucato, E Park, H Ramsey, AT Rewoldt, G Scott, SD Schmidt, G Tang, WM Taylor, G Zarnstorff, MC AF Synakowski, EJ Batha, SH Beer, MA Bell, MG Bell, RE Budny, RV Bush, CE Efthimion, PC Hammett, GW Hahm, TS LeBlanc, B Levinton, F Mazzucato, E Park, H Ramsey, AT Rewoldt, G Scott, SD Schmidt, G Tang, WM Taylor, G Zarnstorff, MC TI Roles of electric field shear and Shafranov shift in sustaining high confinement in enhanced reversed shear plasmas on the TFTR Tokamak SO PHYSICAL REVIEW LETTERS LA English DT Article ID DIII-D TOKAMAK; MAGNETIC SHEAR; FLOW SHEAR; MODE; TRANSPORT; SIMULATIONS; TURBULENCE AB The relaxation of core transport barriers in TFTR enhanced reversed shear plasmas has been studied by varying the radial electric field using different applied torques from neutral beam injection. Transport rates and fluctuations remain low over a wide range of radial electric field shear, but increase when the local E x B shearing rates are driven below a threshold comparable to the fastest linear growth rates of the dominant instabilities. Shafranov-shift-induced stabilization alone is not able to sustain enhanced confinement. RP Synakowski, EJ (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Hammett, Gregory/D-1365-2011 OI Hammett, Gregory/0000-0003-1495-6647 NR 27 TC 101 Z9 101 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2972 EP 2975 DI 10.1103/PhysRevLett.78.2972 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300026 ER PT J AU Nazikian, R Fu, GY Batha, SH Bell, MG Bell, RE Budny, RV Bush, CE Chang, Z Chen, Y Cheng, CZ Darrow, DS Efthimion, PC Fredrickson, ED Gorelenkov, NN Leblanc, B Levinton, FM Majeski, R Mazzucato, E Medley, SS Park, HK Petrov, MP Spong, DA Strachan, JD Synakowski, EJ Taylor, G VonGoeler, S White, RB Wong, KL Zweben, SJ AF Nazikian, R Fu, GY Batha, SH Bell, MG Bell, RE Budny, RV Bush, CE Chang, Z Chen, Y Cheng, CZ Darrow, DS Efthimion, PC Fredrickson, ED Gorelenkov, NN Leblanc, B Levinton, FM Majeski, R Mazzucato, E Medley, SS Park, HK Petrov, MP Spong, DA Strachan, JD Synakowski, EJ Taylor, G VonGoeler, S White, RB Wong, KL Zweben, SJ TI Alpha-particle-driven toroidal Alfven eigenmodes in the tokamak fusion test reactor SO PHYSICAL REVIEW LETTERS LA English DT Article ID DEUTERIUM-TRITIUM EXPERIMENTS; PLASMAS; TFTR; INSTABILITIES; SIMULATIONS AB Alpha-particle-driven toroidal Alfven eigenmodes (TAEs) have been observed for the first time in deuterium-tritium (D-T) plasmas on the tokamak fusion test reactor (TFTR). These modes are observed 100-200 ms following the end of neutral beam injection in plasmas with reduced central magnetic shear and elevated central safety factor [q(0) > 1]. Mode activity is localized to the central region of the discharge (r/a < 0.5) with magnetic fluctuation level <(B)over tilde (perpendicular to)> similar to 10(-5) and toroidal mode numbers in the range n = 2-4, consistent with theoretical calculations of alpha-TAE stability in TFTR. C1 FUS PHYS & TECHNOL,TORRANCE,CA 90503. TROITSK INST FUS & INNOVAT RES,TROITSK,RUSSIA. AF IOFFE PHYS TECH INST,ST PETERSBURG 194021,RUSSIA. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Nazikian, R (reprint author), PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. RI Spong, Donald/C-6887-2012; White, Roscoe/D-1773-2013; Cheng, Chio/K-1005-2014 OI Spong, Donald/0000-0003-2370-1873; White, Roscoe/0000-0002-4239-2685; NR 27 TC 91 Z9 91 U1 0 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2976 EP 2979 DI 10.1103/PhysRevLett.78.2976 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300027 ER PT J AU Wang, LS Cheng, HS AF Wang, LS Cheng, HS TI Growth pathways of metallocarbohedrenes: Cagelike or cubic? SO PHYSICAL REVIEW LETTERS LA English DT Article ID METAL-CARBON NANOCRYSTALS; M8C12 CLUSTERS; TI8C12; CARBOHEDRENES; STABILITY; CARS; TI; PHOTODISSOCIATION; MOLECULES; ACCURATE AB A novel layer-by-layer cubic growth pathway involving C-2 dimers is advanced for large titanium carbide clusters based on observation of new magic numbers in the anions. This growth mechanism explains uniquely all the magic numbers in a multicage growth model previously proposed for large metal carbide clusters, suggesting that the cubic structures, characteristic of the bulk carbide lattices, dominate growth of the large carbide clusters. Experimental and theoretical evidence indicates that the cubic layered growth with C-2 dimers can lead to a new type of highly stable one-dimensional quantum wires. C1 PACIFIC NW LAB, EMSL, RICHLAND, WA 99352 USA. AIR PROD & CHEM INC, ALLENTOWN, PA 18195 USA. RP Wang, LS (reprint author), WASHINGTON STATE UNIV, DEPT PHYS, RICHLAND, WA 99352 USA. NR 49 TC 34 Z9 35 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 2983 EP 2986 DI 10.1103/PhysRevLett.78.2983 PG 4 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300029 ER PT J AU Chen, Y Washburn, J AF Chen, Y Washburn, J TI Island formation and critical thickness in heteroepitaxy - Reply SO PHYSICAL REVIEW LETTERS LA English DT Article ID GROWTH; SI(100); GE RP Chen, Y (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 7 TC 3 Z9 3 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 14 PY 1997 VL 78 IS 15 BP 3028 EP 3028 DI 10.1103/PhysRevLett.78.3028 PG 1 WC Physics, Multidisciplinary SC Physics GA WT633 UT WOS:A1997WT63300041 ER PT J AU Hay, BP AF Hay, BP TI Structural criteria for the design of metal-selective ligands. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 1 EP IEC PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18700002 ER PT J AU Seidl, E Janssen, C Colvin, M AF Seidl, E Janssen, C Colvin, M TI Parallel ab initio quantum chemistry on Pentium-Pro networks SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 SANDIA NATL LABS,DEPT COMP SCI,LIVERMORE,CA 94551. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 1 EP COMP PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502633 ER PT J AU Szostek, B Koropchak, JA Zajac, JJ AF Szostek, B Koropchak, JA Zajac, JJ TI Condensation nucleation light scattering detection for capillary electrophoresis with electrospray interfacing. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439. SO ILLINOIS UNIV,DEPT CHEM & BIOCHEM,CARBONDALE,IL 62901. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 1 EP ANYL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18500359 ER PT J AU Orme, CJ Stewart, FF Peterson, ES Stone, ML AF Orme, CJ Stewart, FF Peterson, ES Stone, ML TI Characterization and testing of polyphosphazene polymers to determine their applicability to membrane separations. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LOCKHEED MARTIN IDAHO TECHNOL CO,IDAHO FALLS,ID 83450. RI Peterson, Eric/B-9127-2017 OI Peterson, Eric/0000-0002-2292-4939 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 2 EP TECH PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502151 ER PT J AU Reynolds, JG AF Reynolds, JG TI Metals and heteroatoms in heavy crude oils. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 2 EP PETR PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18702106 ER PT J AU Sears, MP AF Sears, MP TI Large scale LDA electronic structure calculations on parallel computers SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 2 EP COMP PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18502634 ER PT J AU Ghiorso, A AF Ghiorso, A TI Review of the instrumenstation used for the discovery of new elements during this century SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 LBNL,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 3 EP NUCL PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18701346 ER PT J AU Hill, SE Feller, DF AF Hill, SE Feller, DF TI Theoretical study of copper/thiacrown interactions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 3 EP IEC PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18700004 ER PT J AU Linehan, JC Franz, JA Crump, AE Autrey, T AF Linehan, JC Franz, JA Crump, AE Autrey, T TI Kinetics of rearrangement of the 2-phenoxybenzyl radical to the 2-benzylphenoxy radical: Radical mediated cleavage of the aryl ether C-O bond. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 PACIFIC NW NATL LAB,RICHLAND,WA 99352. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 3 EP FUEL PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18503290 ER PT J AU Buchanan, AC Britt, PF Skeen, JT AF Buchanan, AC Britt, PF Skeen, JT TI Contrasting retrogressive rearrangement pathways during thermolysis of silica-immobilized benzyl phenyl ether SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 4 EP FUEL PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA WP185 UT WOS:A1997WP18503291 ER PT J AU Rogers, RD Dietz, ML Horwitz, EP Bond, AH AF Rogers, RD Dietz, ML Horwitz, EP Bond, AH TI Ligand design for ion separations: Crystal structures of substituted dicyclohexyl-18-crown-6 isomers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 UNIV ALABAMA,DEPT CHEM,TUSCALOOSA,AL 35486. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. EICHROM IND INC,DARIEN,IL 60561. RI Rogers, Robin/C-8265-2013 OI Rogers, Robin/0000-0001-9843-7494 NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD APR 13 PY 1997 VL 213 BP 4 EP IEC PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA WP187 UT WOS:A1997WP18700005 ER EF