FN Thomson Reuters Web of Science™ VR 1.0 PT S AU Wright, SA Lipinski, RJ AF Wright, SA Lipinski, RJ BE ElGenk, MS TI Mass estimates of very small reactor cores fueled by uranium-235, U-233 and Cm-245 SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program AB This paper explores the possibility of manufacturing very small reactors from U-235, U-233 and Cm-245. Pin type reactor systems fueled with uranium or curium metal zirconium hydride (UZrH or CmZrH) are compared with similar designs using U-235, Criticality measurements of homogeneous water uranium systems, suggest that reactor subsystem masses have a broad minimum for hydrogen-to-uranium atom ratios that vary from 25- 250. This paper compares the masses of metal-hydride fueled reactor systems that use U-235, U-233, and Cm-245 fuel with hydrogen-to-metal atom ratios from 20-300 when cooled by gas (HeXe), liquid metal (Na), and water. The results indicate that water cooled reactors in general have the smallest reactor subsytem mass. For gas and liquid-metal cooled reactors U-233 subsystems have total masses that are about 1/2 those of similarly designed U-235 fuel reactors. Reactor subsystems consisting of 11.2 % enriched Cm-245 (balance Cm-244) that can be obtained from fuel reprocessing have system masses comparable to that of U-233, The smallest reactor subsystem masses were on the order of 60-80 kg for U-233 fueled water cooled reactors. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Wright, SA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 875 EP 880 PG 6 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300127 ER PT S AU Kirkpatrick, RC AF Kirkpatrick, RC BE ElGenk, MS TI Magnetized target fusion for advanced space propulsion SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program ID CONFINEMENT AB The magnetized target fusion (MTF) concept is an approach to thermonuclear fusion which is intermediate between the two extremes of inertial and magnetic confinement fusion. A magnetic field is used to suppress electron thermal conduction, but the fusion plasma is heated by compression and inertially confined during the fusion burn phase by an imploding liner or shell. Because the major energy loss mechanisms are suppressed, the work rate required to achieve fusion ignition is greatly reduced, which translates to a greatly reduced requirement for power input to the target. This allows electrical pursed power machines (and possibly other devices) to be used as drivers. The potential advantages that such a relaxation of driver requirements may offer need to be explored. Thio proposed to dynamically form an MTF target plasma and compress it with a dynamically formed spherical liner, which compresses and heats the target plasma to fusion ignition conditions. This paper will discuss the fundamentals of MTF and the feasibility and technical challenges of Thio's novel approach to advanced space propulsion. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kirkpatrick, RC (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 2 Z9 2 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 892 EP 899 PG 8 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300130 ER PT S AU Kodys, AD Emsellem, G Cassady, LD Polk, JE Choueiri, EY AF Kodys, AD Emsellem, G Cassady, LD Polk, JE Choueiri, EY BE ElGenk, MS TI Lithium mass flow control for high power Lorentz Force Accelerators SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program AB A lithium feeding system has been developed to measure and control propellant flow for 30-200 kW Lithium Lorentz Force Accelerators (LiLFAs). The new, mechanically actuated, liquid lithium feed system has been designed and tested as a central component of a campaign to obtain basic data and establish scaling laws and performance relations for these thrusters. Calibration data are presented which demonstrate reliable and controllable feed of liquid lithium to the vaporizer hollow cathode of the thruster at flow rates between 10 and 120 mg/s. The ability to thermally track the liquid lithium through the system by the use of external temperature measurements is demonstrated. In addition, recent developments are presented in the establishment and successful testing of a lithium handling facility and safety procedures allowing for the in-house loading of the feed system and the neutralization, cleaning and disposal of up to 300 g of lithium. C1 Princeton Univ, Elect Propuls & Plasma Dynam Lab, Princeton, NJ 08544 USA. RP Kodys, AD (reprint author), Princeton Univ, Elect Propuls & Plasma Dynam Lab, Princeton, NJ 08544 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 908 EP 915 PG 8 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300132 ER PT S AU Goodwin, DP AF Goodwin, DP BE ElGenk, MS TI A possible propellantless propulsion system SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program AB A newly developed high power solid state switch might have enabled a propellantless propulsion system (PPS), based on the Lent's Law interactions of a very rapidly pulsed magnet. Although only limited propulsion would be provided with each pulse, and then only during the 100-nanosecond ramp-up of the pulse, the newly developed switch produces 400,000 high power pulses per second. A PPS of this type would consist of an electrical power supply, the switch, and a solenoid with a plate on one end to produce an asymmetry in the magnetic field. Other applications might include propulsion with reduced thermal and acoustical signatures, and a means to dampen inertia. C1 US Dept Energy, Off High Energy & Nucl Phys, Germantown, MD 20874 USA. RP Goodwin, DP (reprint author), US Dept Energy, Off High Energy & Nucl Phys, 19901 Germantown Rd, Germantown, MD 20874 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 976 EP 978 PG 3 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300142 ER PT S AU DiStefano, JR Chitwood, LD AF DiStefano, JR Chitwood, LD BE ElGenk, MS TI Oxidation of Mo-Re at reduced oxygen pressures SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program ID ALLOYS AB Rhenium generally improves the properties of molybdenum, and, therefore, there is interest in use of Mo-Re alloys in space system applications. Both Mo and Re have relatively low solubilities for oxygen but readily form oxide scales when exposed to oxidizing environments above similar to 625 K. Studies are being conducted on Mo-41Re to determine the rate of oxidation, type of scale formation, and effects on mechanical properties as a function of temperature and partial pressure of oxygen. Thus far, weight gains associated with formation of MoO2 have been found for Po-2 < 10(-3) Pa (10(-5) torr) in vacuum, and weight losses associated with evaporation of MoO3 at 10(-2) Pa. However, no significant changes in tensile properties were measured. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP DiStefano, JR (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 12 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 1076 EP 1081 PG 6 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300158 ER PT S AU King, DB Luke, JR Zavadil, KR AF King, DB Luke, JR Zavadil, KR BE ElGenk, MS TI The microminiature thermionic converter SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program AB A new generation of thermionic converter, the microminiature thermionic converter (MTC) has been fabricated using semiconductor integrated circuit (IC) fabrication methods and micromachining manufacturing (MM) techniques. The use of IC and MM techniques allows the fabrication of MTCs with micron scale cathode to anode spacing and with anode and cathode materials which will have work functions ranging from 1 eV to 2.5 eV. The use of small cathode to anode spacing and variable electrode work functions gives the MTC the potential to convert heat energy to relatively large current densities Cup to 10s of Amps/cm(2)) at relatively high conversion efficiencies (similar to 25%), well within the range of high end conventional electrical generation equipment. Tests of prototype MTCs have demonstrated energy conversion at several emitter and collector temperatures. Power generated by the prototype MTC is less than expected because of less than optimal emission characteristics encountered with the low work function materials used for the first MTC prototypes. Work is in progress to improve the thermionic emission characteristics of the low work function electrodes. C1 Sandia Natl Labs, Int Nucl Safety & Interface Reliabil Dept, Albuquerque, NM 87185 USA. RP King, DB (reprint author), Sandia Natl Labs, Int Nucl Safety & Interface Reliabil Dept, POB 5800,MS-0744, Albuquerque, NM 87185 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 1152 EP 1157 PG 6 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300170 ER PT S AU Zavadil, KR King, DB Ruffner, JA AF Zavadil, KR King, DB Ruffner, JA BE ElGenk, MS TI A novel thin film dispenser cathode for thermionic emission SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program ID SCANDATE CATHODES AB A thin film dispenser or micro-dispenser cathode can be generated using standard RF sputtering deposition technology. These films are compositionally modulated structures based on W and a multi-component Ba oxide. Annealing to temperatures from 900 to 1300 K results in Ba reduction, transport and diffusion across the emitter surface. A finite temperature range exists (< 1200 K) where a uniform Re coating can be retained at the emitter surface. The metallic coating results in a nearly homogeneous work function based on emission characteristics. These films produce stable emission at higher temperatures (greater than or equal to 1200 K) where the uniform Re coating is lost. Analysis of emission properties yield a work function of 2.2 eV and an apparent emission coefficient of 6 A . cm(-2).K-2 after annealing to 1200 K. This high apparent emission coefficient yields a film suitable for milliwatt power generation applications. Microminiature Thermionic Converters (MTCs) are one potential application for these films. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Zavadil, KR (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 1165 EP 1170 PG 6 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300172 ER PT S AU Goodwin, DP AF Goodwin, DP BE ElGenk, MS TI The Booster Applications Facility SO SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM-2001 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT Space Technology and Applications International Forum (STAIF-2000) on Space Exploration and Transportation - Journey into the Future CY FEB 11-14, 2001 CL ALBUQUERQUE, NM SP US DOE, NASA, Amer Astronaut Soc, AIAA, AIChE, Amer Nucl Soc, Amer Soc Mech, IEEE, Int Astronaut Federat, Inst Space & Nucl Power Studies, NASA Natl Space Grant Coll & Fellowship Program AB In support of the human exploration program, NASA is providing $33 million to the U.S. Department of Energy to construct a radiation simulator, known as the Booster Applications Facility (BAF). The BAF justification is briefly reviewed (e.g., to reduce the radiation risk uncertainties from its present factor of 4 to 15). The BAF beam specifications are provided, as are discussions of the BAF construction schedule and anticipated operating schedules (e.g., initial operation anticipated for October 1, 2002). A breakdown of the BAF construction costs is included and the operating costs are discussed (e.g., $5 to $6 million per year). The BAF laboratory layout and the various types of DOE support for the BAF are summarized, as are the peer reviews of the project. The characteristic parameters of the Alternating Gradient Synchrotron are also included. C1 US Dept Energy, Off High Energy & Nucl Phys, Germantown, MD 20874 USA. RP Goodwin, DP (reprint author), US Dept Energy, Off High Energy & Nucl Phys, 19901 Germantown Rd, Germantown, MD 20874 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-980-7 J9 AIP CONF PROC PY 2001 VL 552 BP 1230 EP 1233 PG 4 WC Engineering, Aerospace; Thermodynamics; Nuclear Science & Technology SC Engineering; Thermodynamics; Nuclear Science & Technology GA BR99Y UT WOS:000168300300182 ER PT S AU Reeves, GD McAdams, KL Friedel, RHW Cayton, TE AF Reeves, G. D. McAdams, K. L. Friedel, R. H. W. Cayton, T. E. BE Song, P Singer, HJ Siscoe, GL TI The Search for Predictable Features of Relativistic Electron Events: Results from the GEM Storms Campaign SO SPACE WEATHER SE Geophysical Monograph Series LA English DT Proceedings Paper CT Chapman Conference on Space Weather CY MAR 20-JUN 24, 2001 CL Clearwater, FL ID RADIATION-BELT; PARTICLES AB We have examined the relativistic electron events associated with four geomagnetic storms driven by CME-produced magnetic clouds in order to discover some of the underlying consistent behavior that is common to these events. The geomagnetic conditions for the four events showed considerable variation as did the fluxes at fixed energies and fixed L-shell. By combining data from nine different satellites and by selecting specific parameters we found several characteristics of the relativistic electron events that were consistent from storm to storm. Our analysis focused on geosynchronous orbit and on L approximate to 4.2 which is near the heart of the outer electron belt. We examined a large number of parameters and combinations of parameters and found that among the most consistent sets were (1) the temporal behavior of the electron fluxes at L approximate to 4.2 and L approximate to 6.6, (2) the temporal evolution of the spectra at L approximate to 4.2 and L approximate to 6.6, and (3) the gradients of the phase space densities between L approximate to 4.2 and L approximate to 6.6. The characteristics of those parameters may be common to all relativistic electron events and if so that they hold important clues to the physical processes operating during these events. The fact that they are common to these four storms already provides an important framework for evaluating the success of various predictive space weather models that are being developed and tested against these four events. C1 [Reeves, G. D.; McAdams, K. L.; Friedel, R. H. W.; Cayton, T. E.] Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Reeves, GD (reprint author), Los Alamos Natl Lab, NIS 1 MS D-466, Los Alamos, NM 87545 USA. EM reeves@lanl.gov RI Friedel, Reiner/D-1410-2012; Reeves, Geoffrey/E-8101-2011 OI Friedel, Reiner/0000-0002-5228-0281; Reeves, Geoffrey/0000-0002-7985-8098 NR 15 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0065-8448 BN 978-0-87590-984-4 J9 GEOPH MONOG SERIES PY 2001 VL 125 BP 305 EP 311 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BOP22 UT WOS:000277201400034 ER PT S AU Back, CA Golovkin, I Mancini, R Missalla, T Landen, OL Lee, RW Klein, L AF Back, CA Golovkin, I Mancini, R Missalla, T Landen, OL Lee, RW Klein, L BE Seidel, J TI Diagnosing plasma gradients using spectral line shapes SO SPECTRAL LINE SHAPES, VOL 11: 15TH ICSLS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 15th International Conference on Spectral Line Shapes CY JUL 10-14, 2000 CL BERLIN, GERMANY SP German Natl Meterol Inst ID INERTIAL CONFINEMENT FUSION; IMPLOSIONS; DENSITY; PHYSICS; LIGHT AB The development of a set of stable implosions using indirectly driven plastic microspheres with argon (0.1 atm) doped deuterium (50 atm) has provided a unique source for testing the plasma spectroscopy of the high energy density imploded core. The core reaches electron densities of > 10(24) cm(-3) with temperatures of similar to 1 keV and has been shown to be reproducible on a shot to shot basis. Moreover, it has been shown that not only the peak temperature and density are consistent, but that the temporal evolution of the mean temperature and density of the final phase of the implosion is also reproducible. These imploding cores provide a unique opportunity to test aspects of plasma spectroscopy that are difficult to study in other plasmas and to develop methods to test stable hydrodynamics. We will present experimental results and discuss spectroscopic analysis algorithms to determine consistent temperature and density fits to determine gradients in the plasma. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Back, CA (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L21, Livermore, CA 94551 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-991-2 J9 AIP CONF PROC PY 2001 VL 559 BP 3 EP 12 PG 10 WC Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical SC Physics GA BS20D UT WOS:000169065800001 ER PT S AU Alexiou, S Lee, RW AF Alexiou, S Lee, RW BE Seidel, J TI Electron line broadening in plasmas: Resolution of the quantum vs. semiclassical calculations puzzle SO SPECTRAL LINE SHAPES, VOL 11: 15TH ICSLS SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 15th International Conference on Spectral Line Shapes CY JUL 10-14, 2000 CL BERLIN, GERMANY SP German Natl Meterol Inst ID SPECTRAL-LINES; IONIZED ATOMS; STARK WIDTHS; B-III; TRANSITIONS; IONS AB Puzzling discrepancies between quantum mechanical (QM) electron impact calculations of isolated ion lines and nonperturbative semiclassical (SC) calculations are reviewed. The origin of these discrepancies was the use of a standard linebroadening literature estimate of the wavefunction extent. The nonperturbative semiclassical calculations are further improved by dropping the long-range approximation and allowing penetrating collisions. This results in excellent agreement with fully quantal calculations for the case of the BIII 2s-2p line. On the other hand the standard perturbative semiclassical method is inadequate even in this particular example, where perturbation theory is valid. Further, the assumption of neglecting the back-reaction in semiclassical calculations is examined. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Alexiou, S (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-399, Livermore, CA 94550 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 1-56396-991-2 J9 AIP CONF PROC PY 2001 VL 559 BP 135 EP 143 PG 9 WC Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical SC Physics GA BS20D UT WOS:000169065800030 ER PT B AU Havener, CC AF Havener, CC BE Ferland, G Savin, DW TI Charge transfer experiment SO SPECTROSCOPIC CHALLENGES OF PHOTOIONIZED PLASMAS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Photoionized Plasmas 2000 Conference CY NOV 15-18, 2001 CL UNIV KENTUCKY, LEXINGTON, KY SP NASA Appl Informat Syst Res Program HO UNIV KENTUCKY ID SELECTIVE ELECTRON-CAPTURE; CROSS-SECTION MEASUREMENTS; LOW-ENERGY COLLISIONS; HE-LIKE IONS; VOLT ENERGIES; MERGED-BEAMS; MOLECULAR-HYDROGEN; ATOMIC-HYDROGEN; SLOW COLLISIONS; H-2 AB Low energy charge transfer is an important process in plasmas where multicharged ions and neutral atoms or molecules can exist at eV/amu energies and below, At eV/amu collision energies there are no scaling laws to characterize the charge transfer cross section and both theory and experiment are difficult. The capabilities of current experimental techniques used to measure low energy total and state-selective cross sections are discussed. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Havener, CC (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 56 TC 5 Z9 5 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-085-4 J9 ASTR SOC P PY 2001 VL 247 BP 17 EP 32 PG 16 WC Astronomy & Astrophysics; Optics; Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Astronomy & Astrophysics; Optics; Physics; Spectroscopy GA BU54X UT WOS:000176291800002 ER PT B AU Foord, ME Heeter, RF Thoe, RS Liedahl, DA Fournier, KB Goldstein, WH Springer, PT Bailey, JE Cuneo, ME Chandler, GA Nash, TJ Phillips, M Keenan, F Rose, S AF Foord, ME Heeter, RF Thoe, RS Liedahl, DA Fournier, KB Goldstein, WH Springer, PT Bailey, JE Cuneo, ME Chandler, GA Nash, TJ Phillips, M Keenan, F Rose, S BE Ferland, G Savin, DW TI Photoionization and heating of a well-characterized iron plasma SO SPECTROSCOPIC CHALLENGES OF PHOTOIONIZED PLASMAS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Photoionized Plasmas 2000 Conference CY NOV 15-18, 2001 CL UNIV KENTUCKY, LEXINGTON, KY SP NASA Appl Informat Syst Res Program HO UNIV KENTUCKY ID DIELECTRONIC RECOMBINATION AB Recent experiments at the Z-facility at Sandia National Laboratory have produced highly photoionized, low temperature iron plasmas in the density ionization parameter range xi = 35-50. Using time resolved X-ray spectroscopy, absorption and emission features from Fe XVI-Fe XIX, Na X, Na XI, F VIII, and F IX in the 9-17 Angstrom wavelength region were observed. The density, temperature, and absolute flux were measured independently, providing a unique integrated benchmark for photoionization and spectral synthesis codes. Absorption data from the expanding plasma are used to determine the charge state distributions. In this brief report, we describe the experimental techniques and the methods of characterization, and highlight some of our recent results. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Foord, ME (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 12 TC 4 Z9 4 U1 1 U2 2 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-085-4 J9 ASTR SOC P PY 2001 VL 247 BP 117 EP 122 PG 6 WC Astronomy & Astrophysics; Optics; Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Astronomy & Astrophysics; Optics; Physics; Spectroscopy GA BU54X UT WOS:000176291800008 ER PT B AU Liedahl, DA Wojdowski, PS Jimenez-Garate, MA Sako, M AF Liedahl, DA Wojdowski, PS Jimenez-Garate, MA Sako, M BE Ferland, G Savin, DW TI X-ray Spectroscopy of accretion disks and stellar winds in X-ray binaries SO SPECTROSCOPIC CHALLENGES OF PHOTOIONIZED PLASMAS SE Astronomical Society of the Pacific Conference Series LA English DT Proceedings Paper CT Photoionized Plasmas 2000 Conference CY NOV 15-18, 2001 CL UNIV KENTUCKY, LEXINGTON, KY SP NASA Appl Informat Syst Res Program HO UNIV KENTUCKY ID ACTIVE GALACTIC NUCLEI; HELIUM-LIKE IONS; HIGH-RESOLUTION SPECTROSCOPY; TRANSMISSION GRATING SPECTROMETER; RADIATION-DRIVEN WINDS; HIGHLY IONIZED IRON; LINE EMISSION; BLACK-HOLES; VELA X-1; CENTAURUS X-3 AB From hot, tenuous gas dominated by Compton processes, to warm, photoionized emission-line regions, to cold, optically thick fluorescing matter, accreting gas flows in X-ray binaries span a huge portion of the parameter space accessible to astrophysical plasmas. The coexistence of such diverse states of material within small volumes (10(33)-10(36) cm(3)) leaves X-ray spectroscopists with a challenging set of problems, since all such matter produces various X-ray spectral signatures when exposed to hard X rays. Emission-line regions in X-ray binaries are characterized by high radiation energy densities, relatively high particle densities, and velocities similar to 1000 km s(-1). In this article, we describe some recent efforts to generate detailed X-ray line spectra from models of X-ray binaries, whose aims are to reproduce spectra acquired with the ASCA, Chandra, and XMM-Newton observatories. With emphasis on the global nature of X-ray line emission in these systems, the article includes separate treatments of high-mass and low-mass systems, as well as summaries of continuum spectroscopy and plasma diagnostics. C1 Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. RP Liedahl, DA (reprint author), Lawrence Livermore Natl Lab, Dept Phys, POB 808, Livermore, CA 94550 USA. EM duane@virgo.llnl.gov; mario@phys.columbia.edu NR 150 TC 13 Z9 13 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-085-4 J9 ASTR SOC P PY 2001 VL 247 BP 417 EP 456 PG 40 WC Astronomy & Astrophysics; Optics; Physics, Fluids & Plasmas; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Astronomy & Astrophysics; Optics; Physics; Spectroscopy GA BU54X UT WOS:000176291800040 ER PT J AU Alam, TM Alam, MK AF Alam, TM Alam, MK TI Chemometric analysis of nuclear magnetic resonance spectroscopy data SO SPECTROSCOPY LA English DT Article ID MULTIVARIATE DATA-ANALYSIS; RESOLUTION ALGORITHM DECRA; NEAR-INFRARED SPECTROSCOPY; LEAST-SQUARES ANALYSIS; SPECTRAL DATA SETS; CURVE RESOLUTION; NMR-SPECTROSCOPY; PATTERN-RECOGNITION; C-13 NMR; CLASSIFICATION AB Chemometric analysis of nuclear magnetic resonance (NMR) spectroscopy has increased dramatically in recent years. Various chemometric techniques have been applied to a wide range of problems in food, agricultural, medical, process, and industrial systems. This article gives a brief review of chemometric analysis of NMR spectral data, including a summary of the types of mixtures and experiments analyzed with chemometric techniques. Common experimental problems encountered during the chemometric analysis of NMR data are also discussed. C1 Sandia Natl Labs, Tech Staff, Albuquerque, NM 87185 USA. RP Alam, TM (reprint author), Sandia Natl Labs, Tech Staff, POB 5800, Albuquerque, NM 87185 USA. NR 51 TC 9 Z9 9 U1 0 U2 3 PU ADVANSTAR COMMUNICATIONS PI DULUTH PA 131 W FIRST ST, DULUTH, MN 55802 USA SN 0887-6703 J9 SPECTROSCOPY JI Spectroscopy PD JAN PY 2001 VL 16 IS 1 BP 18 EP + PG 8 WC Spectroscopy SC Spectroscopy GA 392HA UT WOS:000166404600002 ER PT S AU Bunce, G AF Bunce, G CA Muon g-2 Collaboration BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI The muon g-2 experiment at Brookhaven SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID ANOMALOUS MAGNETIC-MOMENT; POSITIVE MUON AB The muon g-2 experiment at Brookhaven is designed to take advantage of very high proton intensity at the AGS to achieve sensitivity well below the contributions to g-2 from W and Z. The experiment will explore the possibility of new physics coupling to the muon at a mass scale of 5 TeV. This talk presents the experiment, results at 5 parts per million based on data collected in 1998, and data analysis of the 1999 data run which will have a statistical error of +/-1.3 ppm. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Bunce, G (reprint author), Brookhaven Natl Lab, Bldg 510A, Upton, NY 11973 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 46 EP 58 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900004 ER PT S AU Gilman, R AF Gilman, R CA Jefferson Lab Hall A Collaboration BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Polarization in photodisintegration of the deuteron SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID C ANALYZING POWER; CROSS-SECTION; 2-BODY PHOTODISINTEGRATION; ASYMPTOTIC AMPLITUDES; EXCLUSIVE PROCESSES; PHOTON ENERGIES; GEV REGION; QCD; RESONANCES; MOMENTUM AB Recoil proton polarization was measured in deuteron photodisintegration at theta (cm) = 90 degrees for photon energies up to 2.4 GeV. The induced polarization p(y) is consistent with vanishing above 1 GeV, in surprising disagreement with meson-baryon calculations. From pQCD it is generally expected that hadron helicity is conserved, but, the polarization transfer observables do not vanish. As the data are inconsistent with existing meson baryon model predictions, and with expectations from pQCD, we suggest that nonperturbative quark models will be needed to understand the underlying reaction dynamics. C1 Rutgers State Univ, Jefferson Lab, Newport News, VA 23606 USA. RP Gilman, R (reprint author), Rutgers State Univ, Jefferson Lab, Newport News, VA 23606 USA. NR 50 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 69 EP 78 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900006 ER PT S AU Vetter, PA Freedman, SJ Fujikawa, BK Scielzo, ND AF Vetter, PA Freedman, SJ Fujikawa, BK Scielzo, ND BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI The beta-nu correlation using a neutral atom trap SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID DECAY; DECELERATION; EFFICIENCY; CURRENTS; LIMITS; ENERGY; AR-32; BEAM AB By confining up to 500,000 radioactive Na-21 atoms in a magneto-optic trap, we have studied the beta-neutrino correlation. The Na-21 is produced on-line at the Lawrence Berkeley National Laboratory 88 " Cyclotron and trapped using common laser cooling techniques. We detect the low-energy recoil Ne-21 daughter nucleus in coincidence with the decay positron. Using the recoil's time-of-flight, we determine the initial momentum of the recoil nucleus and infer the beta -v correlation. Our current data set has a statistical uncertainty to determine the correlation parameter a to better than 2%, and we are studying potential systematic errors at the few percent level. Other beta decay correlations can be studied using magneto-optically trapped radioactive atoms. Precise measurements of correlation parameters can provide limits on non-Standard Model scalar and tensor interactions, or anomalous induced form factors. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Vetter, PA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, MS 88-205, Berkeley, CA 94720 USA. NR 26 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 89 EP 98 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900008 ER PT S AU Vogelsang, W AF Vogelsang, W BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Nucleon spin structure functions SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID POLARIZED STRUCTURE FUNCTIONS; TO-LEADING ORDER; DEPENDENT PARTON DISTRIBUTIONS; DEEP-INELASTIC-SCATTERING; DRELL-YAN-PROCESS; INTERFERENCE FRAGMENTATION FUNCTIONS; STRUCTURE-FUNCTION G2(X; CHIRAL-ODD; TRANSVERSITY DISTRIBUTION; RADIATIVE-CORRECTIONS AB We briefly review and discuss some aspects of nucleon spin structure functions, focusing on experimental results and their implications. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Vogelsang, W (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Bldg 510A, Upton, NY 11973 USA. NR 96 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 138 EP 153 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900013 ER PT S AU Saito, N AF Saito, N BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Physics with the first polarized-proton collider RHIC SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID DRELL-YAN PROCESS; DEEP-INELASTIC-SCATTERING; NEUTRON SPIN STRUCTURE; STRUCTURE-FUNCTION G(1)(N); PARTON DISTRIBUTIONS; HADRONIC COLLISIONS; GLUON POLARIZATION; MUON SCATTERING; PAIR PRODUCTION; PP COLLISIONS AB Polarized pp collisions at high energy will provide a unique opportunity to study the spin structure of the nucleon and the symmetries in the nature. The physics program with the polarized beams at RHIC is overviewed with the expected sensitivities and the successful commissioning of the first polarized proton beam at RHIC is reported. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Saito, N (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Bldg 510A, Upton, NY 11973 USA. NR 51 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 154 EP 168 PG 5 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900014 ER PT S AU Zelenski, AN AF Zelenski, AN BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Polarized ion sources for high-energy accelerators and colliders SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB The recent progress in polarized ion source development is reviewed, In de operation a 1.0 mA polarized H- ion current is now available from the Optically-Pumped Polarized Ion Source (OPPIS). In pulsed operation a 10 mA polarized H- ion current was demonstrated at the TRIUMF pulsed OPPIS test bench and a 2.5 mA peak current was obtained from an Atomic Beam Source (ABS) at the INR Moscow test bench. The possibilities for future improvements with bath techniques are discussed. A new OPPIS for RHIC spin physics is described. The OPPIS reliably delivered polarized beam for the polarized run at RHIC. The results obtained with a new pulsed ABS injector for the IUCF Cooler Ring are also discussed. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Zelenski, AN (reprint author), Brookhaven Natl Lab, Bldg 930, Upton, NY 11973 USA. NR 11 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 179 EP 188 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900016 ER PT S AU Roser, T AF Roser, T BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Symposium highlights SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB Some of the highlights of the 14th international Symposium on Spin Physics are presented with emphasis on recent and planned progress in experimental tools and facilities. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Roser, T (reprint author), Brookhaven Natl Lab, Bldg 911B, Upton, NY 11973 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 312 EP 319 PG 2 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900028 ER PT S AU Courant, ED AF Courant, ED BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Some milestones in polarized proton beams SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Courant, ED (reprint author), Brookhaven Natl Lab, Bldg 911B, Upton, NY 11973 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 323 EP 325 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900029 ER PT S AU Maruyama, T AF Maruyama, T CA SLD Collaboration BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Symmetry tests in polarized Z(0) decays to b(b)over-barg SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID E(+)E(-) ANNIHILATION; VERTEX DETECTOR; 3 JETS; ORIENTATION; SLD AB We have made the first direct symmetry tests in the decays of polarized Z(0) bosons into fully-identified b (b) over barg states, collected in the SLD experiment at SLAG. We searched for evidence of parity violation at the b (b) over barg vertex by studying the asymmetries in the b-quark polar- and azimuthal-angle distributions, and for evidence of T-odd, CP-even or odd, final-state interactions by measuring angular correlations between the three-jet plane and the Z(0) polarization. We found results consistent with Standard Model expectations and set 95% C.L. limits on anomalous contributions. C1 Stanford Linear Accelerator Ctr, Menlo Park, CA 94025 USA. RP Maruyama, T (reprint author), Stanford Linear Accelerator Ctr, 2575 Sand Hill Rd, Menlo Park, CA 94025 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 361 EP 365 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900035 ER PT S AU Ogawa, A Rykov, VL Saito, N AF Ogawa, A Rykov, VL Saito, N BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Physics beyond SM at RHIC with polarized protons SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID TAU-LEPTON; HADRONIC COLLISIONS; DIPOLE-MOMENTS; BOUNDS AB The capabilities of RHIC with polarized protons to test the Lorentz structure of electroweak interactions and also the properties of MSSM Higgs, should it be discovered, are discussed. C1 Penn State Univ, BNL, Upton, NY 11973 USA. RP Ogawa, A (reprint author), Penn State Univ, BNL, Bldg 510A, Upton, NY 11973 USA. NR 25 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 379 EP 383 PG 5 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900038 ER PT S AU Goto, Y AF Goto, Y CA PHENIX Collaborat BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Measurement of the gluon polarization in the proton at PHENIX SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID QUARK DISTRIBUTIONS; NUCLEON; PHYSICS AB We plan to measure the gluon polarization in the proton at PHENIX using RHIC polarized proton collisions. Many channels of physic signals will be detected for this purpose in both the central arms and the muon arms of the PHENIX detector. Sensitivities to the gluon polarization in prompt photon, pion, and heavy-flavor production measurements are discussed. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Goto, Y (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Bldg 510A, Upton, NY 11973 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 442 EP 446 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900051 ER PT S AU Perdekamp, MG Ogawa, A AF Perdekamp, MG Ogawa, A BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Future transversity measurements at RHIC SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID SPIN ASYMMETRIES; DISTRIBUTIONS; FRAGMENTATION; COLLISIONS; HADRON AB The PHENIX and STAR collaborations at Brookhaven National Laboratory will probe the spin structure of the proton in polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC). Initial data taking is planned for 2001 with polarized proton beams at roots = 200 GeV. Double spin asymmetries with longitudinal polarization will give access to the proton gluon polarization distributions and parity violating single spin asymmetries will provide information on quark and anti-quark polarizations. Measurements of transverse spin asymmetries will permit the extraction of the currently unknown transversity distributions deltaq. We present first studies of experimental sensitivities for single transverse spin asymmetries at RHIC. C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Perdekamp, MG (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Bldg 510A, Upton, NY 11973 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 457 EP 460 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900054 ER PT S AU Guryn, W AF Guryn, W BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Total and Differential Cross Sections and Polarization Effects in pp Elastic Scattering at RHIC SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID SPIN DEPENDENCE; HADRONIC INTERFERENCE; PROTON-SCATTERING; ENERGIES AB We shall describe an approved experiment [1] at the Relativistic Heavy Ion Collider (RHIC) Total and Differential Cross Sections and Polarization Effects in pp Elastic Scattering at RHIC, PP2PP experiment. By measuring single spin asymmetries such as A(N), double spin correlation parameter A(NN), and cross section difference Delta sigma (T) = sigma (tot)(up arrow,down arrow) - sigma (tot)(up arrow,up arrow), we will be able to determine the helicity amplitudes phi (i). Those amplitudes are not well known now, so their systematic study at RHIC will help to understand the spin structure of the nucleon and of the exchanged mediators of the force. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Guryn, W (reprint author), Brookhaven Natl Lab, Bldg 510C, Upton, NY 11973 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 519 EP 523 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900066 ER PT S AU Spinka, H Allgower, C Kasprzyk, T Krueger, K Underwood, D Yokosawa, A Bunce, G Huang, H Makdisi, Y Roser, T Syphers, M Belikov, NI Derevschikov, AA Matulenko, YA Nogach, LV Nurushev, SB Pavlinov, AI Vasiliev, AN Bai, M Lee, SY Goto, Y Hayashi, N Ichihara, T Okamura, M Saito, N En'yo, H Imai, K Kondo, Y Nakada, Y Nakamura, M Sato, HD Okamura, H Sakai, H Wakasa, T Baturine, V Ogawa, A Ghazikhanian, V Igo, G Trentalange, S Whitten, C AF Spinka, H Allgower, C Kasprzyk, T Krueger, K Underwood, D Yokosawa, A Bunce, G Huang, H Makdisi, Y Roser, T Syphers, M Belikov, NI Derevschikov, AA Matulenko, YA Nogach, LV Nurushev, SB Pavlinov, AI Vasiliev, AN Bai, M Lee, SY Goto, Y Hayashi, N Ichihara, T Okamura, M Saito, N En'yo, H Imai, K Kondo, Y Nakada, Y Nakamura, M Sato, HD Okamura, H Sakai, H Wakasa, T Baturine, V Ogawa, A Ghazikhanian, V Igo, G Trentalange, S Whitten, C BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI A(N) for inclusive pi(+/-) production at 21.6 GeV/c from C and LH2 SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID SINGLE-SPIN ASYMMETRIES; POLARIZED PROTON-BEAM; ANALYZING POWER; HARD-SCATTERING; PION-PRODUCTION; 18.5 GEV/C; QUARKS; P-UP-ARROW-P->PI-X; ANTIPROTONS; QCD AB Measurements of the spin asymmetry AN for the inclusive reactions (p) over right arrowC --> pi (+/-) X, pX and (p) over right arrowp --> pi (+/-) X are presented. Comparisons of hydrogen and carbon target results, and of data at 21.6 GeV/c and 200 GeV/c are given. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Spinka, H (reprint author), Argonne Natl Lab, 9700 S Cass Ave,Bldg 362 HEP, Argonne, IL 60439 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 534 EP 538 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900069 ER PT S AU Wojtsekhowski, BB AF Wojtsekhowski, BB CA RCS 99-114 Collaborat BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Polarization observables in Wide Angle Compton Scattering SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID PERTURBATIVE QCD; FORM-FACTORS C1 TJNAF, Newport News, VA 23606 USA. RP Wojtsekhowski, BB (reprint author), TJNAF, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 566 EP 570 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900075 ER PT S AU Hansen, JO AF Hansen, JO CA Jefferson Lab E95-001 Collaborat BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Precise measurement of the spin-dependent transverse asymmetry in quasielastic (3)(H)over-right-arrowe((e)over-right-arrow,e ') and the neutron magnetic form factor SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID QUASI-ELASTIC SCATTERING; POLARIZED ELECTRONS; INCLUSIVE SCATTERING; HE-3; TARGETS AB We report a measurement of the transverse asymmetry A(T') in (3)(H) over right arrowe((e) over right arrow, e') quasielastic scattering with high statistical and systematic precision at Q(2)-values from 0.1 to 0.6 (GeV/c)(2). Using a state-of-the-art Faddeev calculation, the neutron magnetic form factor G(M)(n) is extracted for Q(2) = 0.1 and 0.2 (GeV/c)2 with an experimental uncertainty of less than 2%. The results are in excellent agreement with those recently obtained at NIKHEF and Mainz using a deuterium target. C1 TJNAF, Newport News, VA 23606 USA. RP Hansen, JO (reprint author), TJNAF, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 17 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 576 EP 580 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900077 ER PT S AU Joo, K AF Joo, K CA CLAS Collaborat BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Single pi(0) electroproduction from CLAS data at Jefferson Lab SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID TRANSITION AB New measurements of the electroproduction of the Delta (1232) resonance through the p(e,e'p)pi (o) and p((e) over right arrow ,e'p) pi (o) reactions have been performed. The data were taken with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using polarized and unpolarized incident electron beam. Cross sections were measured simultaneously with continuous coverage over a large range of four-momentum transfer Q(2)=(0.3-1.2 GeV2), Decay angular distributions in the p pi (o) center-of-mass were obtained over the full range of cos theta (c.m.) and phi (c.m.). The high statistical accuracy of this data set is expected to provide strong constraints on dynamic models of the N --> Delta transition form factors. C1 TJNAF, Newport News, VA 23606 USA. RP Joo, K (reprint author), TJNAF, 12000 Jefferson Ave 12H, Newport News, VA 23606 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 581 EP 585 PG 5 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900078 ER PT S AU Bai, M Roser, T AF Bai, M Roser, T BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Crossing a coupling spin resonance with an RF dipole SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB In accelerators, due to quadrupole roll errors and solenoid fields, the polarized proton acceleration often encounters coupling spin resonances. In the Brookhaven AGS, the coupling effect comes from the solenoid partial snake which is used to overcome imperfection resonances. The coupling spin resonance strength is proportional to the amount of coupling as well as the strength of the corresponding intrinsic spin resonance. The coupling resonance can cause substantial beam polarization loss if its corresponding intrinsic spin resonance is very strong. A new method of using an horizontal RF dipole to induce a full spin flip crossing both the intrinsic and its coupling spin resonances is studied in the Brookhaven's AGS. Numerical simulations show that a full spin flip can be induced after crossing the two resonances by using a horizontal RF dipole to induce a large vertical coherent oscillation. C1 Brookhaven Natl Lab, CA Dept, Upton, NY 11973 USA. RP Bai, M (reprint author), Brookhaven Natl Lab, CA Dept, Bldg 911B, Upton, NY 11973 USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 741 EP 745 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900109 ER PT S AU Cameron, P Conte, M Ferro, M Gemme, G Luccio, AU MacKay, WW Palazzi, M Parodi, R Pusterla, M AF Cameron, P Conte, M Ferro, M Gemme, G Luccio, AU MacKay, WW Palazzi, M Parodi, R Pusterla, M BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Stern-gerlach interaction in Fermion beams SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB The Stern-Gerlach interaction, between a moving charged particle endowed with a magnetic moment and a radio-frequency e.m. field, is studied by means of a semi-classical approach. Theoretical results are presented, and a possible experimental check of this theory is discussed. C1 Brookhaven Natl Lab, RHIC Project, Upton, NY 11973 USA. RP Cameron, P (reprint author), Brookhaven Natl Lab, RHIC Project, Upton, NY 11973 USA. RI Gemme, Gianluca/C-7233-2008 OI Gemme, Gianluca/0000-0002-1127-7406 NR 13 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 785 EP 789 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900118 ER PT S AU Huang, H Alekseev, I Bunce, G Deshpande, A Fields, D Imai, K Kanavets, V Kurita, K Lozowski, B MacKay, W Makdisi, Y Roser, T Saito, N Spinka, H Svirida, D Tojo, J Underwood, D AF Huang, H Alekseev, I Bunce, G Deshpande, A Fields, D Imai, K Kanavets, V Kurita, K Lozowski, B MacKay, W Makdisi, Y Roser, T Saito, N Spinka, H Svirida, D Tojo, J Underwood, D BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Commissioning of RHIC p-carbon CNI polarimeter SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB An innovative polarimeter based on proton carbon elastic scattering in the Coulomb Nuclear Interference (CNI) region has been installed and commissioned in the Blue ring of RHIC during the first RHIC polarized proton commissioning. The polarimeter consists of ultra-thin carbon targets and four silicon detectors. All elements are in a 1.6 meter target chamber. It worked very well as a pivotal tool during the commissioning. It demonstrated that the RHIC snake magnets rotate spin to the expected direction, The results also show that polarized proton beam has been accelerated in RHIC and the polarization is maintained up to 29 GeV. C1 Brookhaven Natl Lab, CA Dept, Upton, NY 11973 USA. RP Huang, H (reprint author), Brookhaven Natl Lab, CA Dept, Bldg 911B, Upton, NY 11973 USA. RI Alekseev, Igor/J-8070-2014; Svirida, Dmitry/R-4909-2016 OI Alekseev, Igor/0000-0003-3358-9635; NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 795 EP 799 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900120 ER PT S AU Wei, X Lincoln, F Lowry, M Saitoh, T Sandorfi, AM AF Wei, X Lincoln, F Lowry, M Saitoh, T Sandorfi, AM BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI The new LEGS Highly Polarized Frozen-Spin Solid HD Target Facility SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB Three large highly H polarized frozen-spin HD targets (1.3 moles each in the solid phase) have been produced simultaneously at 20 mK and 15 Tesla with a new production facility located at Brookhaven National Laboratory, After freezing the hydrogen spins into alignment, the targets were cold transferred (at 2.5 K and 0.016 Tesla) to other cryostats with <2% loss in polarization Highlights of the new target polarization facility are discussed. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Wei, X (reprint author), Brookhaven Natl Lab, 1-233 Bldg 510A, Upton, NY 11973 USA. NR 5 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 846 EP 850 PG 3 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900129 ER PT S AU Steigerwald, M AF Steigerwald, M BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI MeV Mott polarimetry at Jefferson Lab SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS AB In the recent past, Mott polarimetry has been employed only at low electron beam energies (approximate to 100keV). Shortly after J. Sromicki demonstrated the first Mott scattering experiment on lead foils at 14 MeV (MAMI, 1994), a high energy Mott scattering polarimeter was developed at Thomas Jefferson National Accelerator Facility (5 MeV, 1995). An instrumental precision of 0.5 % was achieved due to dramatic improvement in eliminating the background signal by means of collimation, shielding, time of flight and coincidence methods. Measurements for gold targets between 0.05 mum and 5 mum for electron energies between 2 and 8 MeV are presented. A model was developed to explain the depolarization effects in the target foils due to double scattering. The instrumental helicity correlated asymmetries were measured to smaller than 0.1%. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Steigerwald, M (reprint author), Jochgasse 45, D-73434 Aalen, Germany. NR 6 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 935 EP 942 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900141 ER PT S AU Poelker, M Adderley, P Clark, J Day, A Grames, J Hansknecht, J Hartmann, P Kazimi, R Rutt, P Sinclair, C Steigerwald, M AF Poelker, M Adderley, P Clark, J Day, A Grames, J Hansknecht, J Hartmann, P Kazimi, R Rutt, P Sinclair, C Steigerwald, M BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Polarized source performance and developments at Jefferson Lab SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID LASER AB The polarized photoinjector at Jefferson Lab continues to provide high average current, high polarization, high quality beam to nuclear physics Users in as many as three endstations simultaneously. Long lifetime operation has been obtained from two identical polarized guns. A new high power modelocked ti-sapphire laser has been constructed to enhance the effective operating lifetime of the photoinjector. Efforts to enhance beam polarization and reduce helicity correlated beam systematic effects are underway. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Poelker, M (reprint author), Thomas Jefferson Natl Accelerator Facil, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 9 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 943 EP 948 PG 4 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900142 ER PT S AU Maruyama, T Clendenin, JE Garwin, EL Kirby, RE Mulhollan, GA Prepost, R Prescott, CY Subashiev, AV AF Maruyama, T Clendenin, JE Garwin, EL Kirby, RE Mulhollan, GA Prepost, R Prescott, CY Subashiev, AV BE Hatanaka, K Nakano, T Imai, K Ejiri, H TI Investigations of the charge limit phenomenon in GaAs photocathodes SO SPIN 2000 SE AIP CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 14th International Spin Physics Symposium CY OCT 16-21, 2000 CL OSAKA UNIV, RES CTR NUCL PHYS, OSAKA, JAPAN SP Ctr Excellence HO OSAKA UNIV, RES CTR NUCL PHYS ID ELECTRON SOURCE AB The doping concentration dependence of the charge limit phenomenon is studied using a set of thin unstrained GaAs. The p-type doping concentration ranges from 5x10(18) cm(-3) to 5x10(19) cm-3. The surface photovoltage effect on photoemission is found to diminish rapidly with increasing doping concentration. The doping concentration effect, on electron polarization is studied using high surface doped strained GaAs. The charge enhancement is explored using a direct, lateral surface charge sink in the form of a metallic grid overlaid on the surface. C1 SLAC, Menlo Park, CA 94025 USA. RP Maruyama, T (reprint author), SLAC, 2575 Sand Hill Rd, Menlo Park, CA 94025 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0008-3 J9 AIP CONF PROC PY 2001 VL 570 BP 976 EP 981 PG 2 WC Instruments & Instrumentation; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Physics GA BS47P UT WOS:000169963900148 ER PT B AU Duchaineau, MA Bertram, M Porumbescu, S Hamann, B Joy, KI AF Duchaineau, MA Bertram, M Porumbescu, S Hamann, B Joy, KI BE Durikovic, R Czanner, S TI Interactive display of surfaces using subdivision surfaces and wavelets SO SPRING CONFERENCE ON COMPUTER GRAPHICS, PROCEEDINGS LA English DT Proceedings Paper CT 17th Spring Conference on Computer Graphics (SCCG 2001) CY APR 25-28, 2001 CL BUDMERICE, SLOVAKIA SP COFAX AB Complex surfaces and solids are produced by large-scale modeling and simulation activities in a variety of disciplines. Productive interaction with these simulations requires that these surfaces or solids be viewable at interactive rates - Yet many of these surfaces/solids can contain hundreds of millions of polygons/polyhedra. Interactive display of these objects requires compression techniques to minimize storage, and fast view-dependent triangulation techniques to drive the graphics hardware. In this paper, ve review recent advances in subdivision-surface wavelet compression and optimization that can be used to provide a framework for both compression and triangulation. These techniques can be used to produce suitable approximations of complex surfaces of arbitrary, topology, and can be used to determine suitable triangulations for display. The techniques can be used in a variety of applications in computer graphics, computer animation and visualization. C1 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. RP Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, POB 808,L-561, Livermore, CA 94551 USA. EM porumbes@cs.ucdavis.edu; hamann@cs.ucdavis.edu; joy@cs.ucdavis.edu NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1215-1 PY 2001 BP 118 EP 127 DI 10.1109/SCCG.2001.945346 PG 10 WC Computer Science, Software Engineering SC Computer Science GA BS91Q UT WOS:000171369900015 ER PT S AU Chacko, T Cole, DR Horita, J AF Chacko, T Cole, DR Horita, J BE Valley, JW Cole, DR TI Equilibrium oxygen, hydrogen and carbon isotope fractionation factors applicable to geologic systems SO STABLE ISOTOPE GEOCHEMISTRY SE Reviews in Mineralogy & Geochemistry LA English DT Review ID AQUEOUS SALT-SOLUTIONS; LIQUID WATER EQUILIBRATION; STABLE-ISOTOPE; METAMORPHIC ROCKS; D/H FRACTIONATION; HIGH-TEMPERATURE; CLAY-MINERALS; EXPERIMENTAL CALIBRATION; ELEVATED-TEMPERATURES; CALCIUM-CARBONATE C1 Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada. Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. RP Chacko, T (reprint author), Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada. RI Chacko, Thomas/F-2269-2011 NR 318 TC 180 Z9 184 U1 11 U2 87 PU MINERALOGICAL SOC AMER PI CHANTILLY PA 3635 CONCORDE PKWY STE 500, CHANTILLY, VA 20151-1125 USA SN 1529-6466 BN 0-939950-55-3 J9 REV MINERAL GEOCHEM JI Rev. Mineral. Geochem. PY 2001 VL 43 BP 1 EP 81 DI 10.2138/gsrmg.43.1.1 PG 81 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA BT79K UT WOS:000174072300001 ER PT S AU Cole, DR Chakraborty, S AF Cole, DR Chakraborty, S BE Valley, JW Cole, DR TI Rates and mechanisms of isotopic exchange SO STABLE ISOTOPE GEOCHEMISTRY SE Reviews in Mineralogy & Geochemistry LA English DT Review ID OXYGEN SELF-DIFFUSION; EXPERIMENTAL HYDROGEN ISOTOPE; GRAIN-BOUNDARY DIFFUSION; AQUEOUS SALT-SOLUTIONS; MINERAL-FLUID SYSTEMS; MOLECULAR-DYNAMICS SIMULATIONS; LIQUID WATER EQUILIBRATION; ION MICROPROBE ANALYSIS; FISCHER-TROPSCH SYNTHESIS; YTTRIUM-ALUMINUM-GARNET C1 Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. Ruhr Univ Bochum, Inst Geol Mineral & Geophys, Bochum, Germany. RP Cole, DR (reprint author), Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. NR 530 TC 96 Z9 98 U1 2 U2 35 PU MINERALOGICAL SOC AMER PI CHANTILLY PA 3635 CONCORDE PKWY STE 500, CHANTILLY, VA 20151-1125 USA SN 1529-6466 BN 0-939950-55-3 J9 REV MINERAL GEOCHEM JI Rev. Mineral. Geochem. PY 2001 VL 43 BP 83 EP 223 DI 10.2138/gsrmg.43.1.83 PG 141 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA BT79K UT WOS:000174072300002 ER PT S AU van Breugel, W Reuland, M De Breuck, C Rottgering, H AF van Breugel, W Reuland, M De Breuck, C Rottgering, H BE Tacconi, L Lutz, D TI The BIGGEST starbursts at the HIGHEST redshifts SO STARBURST GALAXIES: NEAR AND FAR, PROCEEDINGS SE SPRINGER PROCEEDINGS IN PHYSICS LA English DT Proceedings Paper CT Workshop on Starburst Galaxies: Near and Far CY SEP 10-15, 2000 CL RINGBERG CASTLE, GERMANY SP Max Planck Inst, Extraterrestr Phys ID RADIO GALAXY B2-0902+34 AB The BIGGEST starbursts at the HIGHEST redshifts are associated with high redshift radio galaxies (HzRGs). They may well mark the beginnings of the most. massive galaxies seen today. We review current evidence in support. of large scale starbursts in HzRGs, kind will discuss recent results of sub-aim observations. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP van Breugel, W (reprint author), Lawrence Livermore Natl Lab, L-413, Livermore, CA 94550 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0930-8989 BN 3-540-41472-X J9 SPRINGER PROC PHYS PY 2001 VL 88 BP 101 EP 105 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BT51L UT WOS:000173182100013 ER PT B AU Liang, Y Lea, AS McCready, DE Meethunkij, P AF Liang, Y Lea, AS McCready, DE Meethunkij, P BE Baer, DR Clayton, CR Davis, GD Halada, GP TI Synthesis and characterization of self-assembled Cu2O nano-dots SO STATE-OF-THE ART APPLICATION OF SURFACE AND INTERFACE ANALYSIS METHODS TO ENVIRONMENTAL MATERIALS INTERACTIONS: IN HONOR OF JAMES E. CASTLE'S 65TH YEAR, PROCEEDINGS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT International Symposium on State-of-the-Art Application of Surface and Interface Analysis Methods to Environmental Material Interaction held in Honor of James F Castle CY MAR 26-27, 2001 CL WASHINGTON, D.C. SP Electrochem Soc, Corros Div, ASTM Com E-42 Surface Analysis ID QUANTUM DOTS; GROWTH AB Self-assembled Cu2O nano-dots have been synthesized on single-crystal SrTiO3 substrates using oxygen-plasma-assisted molecular beam epitaxy (OPA-MBE), and characterized using a number of different techniques including atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), and scanning Auger microscopy (SAM). It was found that similar to conventional semiconductor systems the growth of Cu2O nano-dots underwent shape/size transformations at different stages of growth. However, the transformations of Cu2O/SrTiO3 are more complex and involve no Cu2O wetting layer at the SrTiO3 surface, thus suggesting that the detailed mechanisms involved in shape/size transformations of Cu2O/SrTiO3 may differ from those of semiconductors. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Liang, Y (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. NR 13 TC 11 Z9 11 U1 0 U2 5 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-311-3 J9 ELEC SOC S PY 2001 VL 2001 IS 5 BP 125 EP 133 PG 9 WC Chemistry, Analytical; Materials Science, Characterization & Testing; Spectroscopy SC Chemistry; Materials Science; Spectroscopy GA BX89S UT WOS:000186759900010 ER PT B AU Gillman, ES AF Gillman, ES BE Baer, DR Clayton, CR Davis, GD Halada, GP TI Scanning near-field infrared microscopy SO STATE-OF-THE ART APPLICATION OF SURFACE AND INTERFACE ANALYSIS METHODS TO ENVIRONMENTAL MATERIALS INTERACTIONS: IN HONOR OF JAMES E. CASTLE'S 65TH YEAR, PROCEEDINGS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT International Symposium on State-of-the-Art Application of Surface and Interface Analysis Methods to Environmental Material Interaction held in Honor of James F Castle CY MAR 26-27, 2001 CL WASHINGTON, D.C. SP Electrochem Soc, Corros Div, ASTM Com E-42 Surface Analysis ID FREE-ELECTRON LASER; OPTICAL MICROSCOPY; SPECTROSCOPY; RESOLUTION; MODE; SCATTERING AB Commonly, location specific chemical identification by means of vibrational spectroscopy in the infrared region is largely restricted to samples of macroscopic dimensions, on the order of one to several microns; the scale of the examined area is completely determined by the diffraction limit of the incident radiation. However, chemical identification at length scales less than the diffraction limit is possible using a scanned probe technique, the Scanning Near-Field Infrared Microscope (SNFIM). Using a scanned probe technique in the near-field, resolution of chemical features on the order of lambda/20 or approximate to 100 nm can be achieved. An overview of previous experimental results using a free electron laser (FEL) and more conventional infrared sources will be discussed. Recent results from the SNFIM experiment at Jefferson Lab will also be presented. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Gillman, ES (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-311-3 J9 ELEC SOC S PY 2001 VL 2001 IS 5 BP 134 EP 138 PG 5 WC Chemistry, Analytical; Materials Science, Characterization & Testing; Spectroscopy SC Chemistry; Materials Science; Spectroscopy GA BX89S UT WOS:000186759900011 ER PT B AU Baer, DR Liang, Y Lea, AS Amonette, JE Colton, NG AF Baer, DR Liang, Y Lea, AS Amonette, JE Colton, NG BE Baer, DR Clayton, CR Davis, GD Halada, GP TI Scanning-force microscopy measurements of dissolution and growth processes: CaCO3 examples SO STATE-OF-THE ART APPLICATION OF SURFACE AND INTERFACE ANALYSIS METHODS TO ENVIRONMENTAL MATERIALS INTERACTIONS: IN HONOR OF JAMES E. CASTLE'S 65TH YEAR, PROCEEDINGS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT International Symposium on State-of-the-Art Application of Surface and Interface Analysis Methods to Environmental Material Interaction held in Honor of James F Castle CY MAR 26-27, 2001 CL WASHINGTON, D.C. SP Electrochem Soc, Corros Div, ASTM Com E-42 Surface Analysis ID CALCITE DISSOLUTION; PROBE MICROSCOPY; WATER INTERFACE; SURFACE; KINETICS; MODEL; MORPHOLOGY; CORROSION; DYNAMICS AB Scanning-Force Microscopy is a relatively new and important tool for examination of materials as they interact with their environment. The ability to perform these studies in real time and to observe their responses to changes in their environment complements many other surface-sensitive methods. In this paper, dissolution and growth studies of calcite provide examples of both kinetic and thermodynamic information that can be gained when making measurements in an aqueous environment, sometimes as a function of time. The relationship between the shape of pits formed at equilibrium and step energies, the influence of solution flow on the shape of "deep" pits, and the epitaxial growth of a Mn-rich calcite phase are discussed. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Baer, DR (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Baer, Donald/J-6191-2013 OI Baer, Donald/0000-0003-0875-5961 NR 32 TC 0 Z9 0 U1 1 U2 4 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-311-3 J9 ELEC SOC S PY 2001 VL 2001 IS 5 BP 139 EP 148 PG 10 WC Chemistry, Analytical; Materials Science, Characterization & Testing; Spectroscopy SC Chemistry; Materials Science; Spectroscopy GA BX89S UT WOS:000186759900012 ER PT B AU McBreen, J Balasubramanian, M AF McBreen, J Balasubramanian, M BE Baer, DR Clayton, CR Davis, GD Halada, GP TI X-ray absorption spectroscopy: Application to electrode surface and interface analysis SO STATE-OF-THE ART APPLICATION OF SURFACE AND INTERFACE ANALYSIS METHODS TO ENVIRONMENTAL MATERIALS INTERACTIONS: IN HONOR OF JAMES E. CASTLE'S 65TH YEAR, PROCEEDINGS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT International Symposium on State-of-the-Art Application of Surface and Interface Analysis Methods to Environmental Material Interaction held in Honor of James F Castle CY MAR 26-27, 2001 CL WASHINGTON, D.C. SP Electrochem Soc, Corros Div, ASTM Com E-42 Surface Analysis ID FINE-STRUCTURE; HYDRIDE ELECTRODES; FILMS; EXAFS AB Although x-ray absorption spectroscopy (XAS) is a bulk spectroscopy, proper design of experiments permit its application to surface and interface analysis. Examples are the use of glancing angle incidence x-rays and fluorescence detection to study underpotential deposited (UPD) monolayers on single crystal surfaces and the study of passive films on AlCr alloys by the use of thin film (similar to20Angstrom) alloy electrodes deposited on a Ta coated Mylar window that is in contact with the cell electrolyte. XAS can be used to study surface processes on fuel cell electrocatalysts. The particle size of these electrocatalysts is typically 2-4 nm. A significant fraction of the atoms (30-50%) in the electrocatalyst are surface atoms. Transmission or fluorescence XAS can detect surface processes. XAS can also be used to investigate corrosion of metal hydride battery electrodes. This is possible because the hydride alloy electrodes consist of small particles (similar to3mu) and the corrosion of cycled electrode can consume 5%, or more, of the alloy. These alloys can contain as many as nine components. The element specific nature of XAS make it a powerful technique for corrosion studies of these alloys. The paper will show examples of the application of XAS to the study of carbon supported Pt and PtSn electrocatalysts and corrosion processes in metal hydride electrodes. C1 Brookhaven Natl Lab, Energy Sci & Technol Dept, Div Mat & Chem Sci, Upton, NY 11973 USA. RP McBreen, J (reprint author), Brookhaven Natl Lab, Energy Sci & Technol Dept, Div Mat & Chem Sci, Upton, NY 11973 USA. NR 17 TC 0 Z9 0 U1 0 U2 4 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-311-3 J9 ELEC SOC S PY 2001 VL 2001 IS 5 BP 163 EP 177 PG 15 WC Chemistry, Analytical; Materials Science, Characterization & Testing; Spectroscopy SC Chemistry; Materials Science; Spectroscopy GA BX89S UT WOS:000186759900014 ER PT B AU Windisch, CF Baer, DR Engelhard, MH Danielson, MJ Jones, RH AF Windisch, CF Baer, DR Engelhard, MH Danielson, MJ Jones, RH BE Baer, DR Clayton, CR Davis, GD Halada, GP TI Effects of Mg and Cu on Al corrosion in alkaline solution SO STATE-OF-THE ART APPLICATION OF SURFACE AND INTERFACE ANALYSIS METHODS TO ENVIRONMENTAL MATERIALS INTERACTIONS: IN HONOR OF JAMES E. CASTLE'S 65TH YEAR, PROCEEDINGS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT International Symposium on State-of-the-Art Application of Surface and Interface Analysis Methods to Environmental Material Interaction held in Honor of James F Castle CY MAR 26-27, 2001 CL WASHINGTON, D.C. SP Electrochem Soc, Corros Div, ASTM Com E-42 Surface Analysis AB In the effort to understand the influence of Mg and Cu segregated to grain boundaries on the Intergranular Stress Corrosion Cracking (IGSCC) of Al alloys, the electrochemical properties of surfaces prepared to simulate the composition of a grain boundaries have been examined using a combined electrochemical/surface analysis system. This paper describes the corrosion responses of pure Al, pure Al implanted with Mg and Cu, and some Cu containing Al alloys. The samples were tested in a potential 100 mV anodic of the open-circuit potential. Both Cu and Mg were found to influence the corrosion in different ways. C1 Pacific NW Natl Lab, Richland, WA 99332 USA. RP Windisch, CF (reprint author), Pacific NW Natl Lab, Box 999, Richland, WA 99332 USA. RI Engelhard, Mark/F-1317-2010; Baer, Donald/J-6191-2013 OI Baer, Donald/0000-0003-0875-5961 NR 8 TC 0 Z9 0 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-311-3 J9 ELEC SOC S PY 2001 VL 2001 IS 5 BP 251 EP 260 PG 10 WC Chemistry, Analytical; Materials Science, Characterization & Testing; Spectroscopy SC Chemistry; Materials Science; Spectroscopy GA BX89S UT WOS:000186759900022 ER PT B AU Isaacs, HS Schmuki, P Virtanen, S AF Isaacs, HS Schmuki, P Virtanen, S BE Baer, DR Clayton, CR Davis, GD Halada, GP TI In situ studies of corrosion using X-ray absorption near spectroscopy (Xanes) SO STATE-OF-THE ART APPLICATION OF SURFACE AND INTERFACE ANALYSIS METHODS TO ENVIRONMENTAL MATERIALS INTERACTIONS: IN HONOR OF JAMES E. CASTLE'S 65TH YEAR, PROCEEDINGS SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT International Symposium on State-of-the-Art Application of Surface and Interface Analysis Methods to Environmental Material Interaction held in Honor of James F Castle CY MAR 26-27, 2001 CL WASHINGTON, D.C. SP Electrochem Soc, Corros Div, ASTM Com E-42 Surface Analysis ID GROWN OXIDE-FILMS; FE-CR ALLOYS; PASSIVE FILM; CONVERSION COATINGS; SPUTTERED ALLOYS; ALUMINUM; IRON; CHROMATE; MECHANISM; REDUCTION AB Applications of x-ray absorption near-edge spectroscopy (XANES) and the design of cells for in situ corrosion studies are reviewed. Passive films studies require very thin metal or alloy layers be used having a thickness of the order of the films formed because of penetration of the x-ray beam into the metal substrate. The depth of penetration in water also limits the thickness of solutions that can be used because of water reduces the x-ray intensity. Solution thickness must also be limited in studies of conversion layer formation studies because the masking of the Cr in solution, Illustrative examples are taken from the anodic behavior of Al-Cr alloys, the growth of passive films on Fe and stainless steels, and the formation of chromate conversion layers on Al. C1 Brookhaven Natl Lab, Div Mat Sci, Energy Sci & Technol Dept, Upton, NY 11973 USA. RP Isaacs, HS (reprint author), Brookhaven Natl Lab, Div Mat Sci, Energy Sci & Technol Dept, Upton, NY 11973 USA. NR 34 TC 0 Z9 0 U1 1 U2 3 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-311-3 J9 ELEC SOC S PY 2001 VL 2001 IS 5 BP 271 EP 281 PG 11 WC Chemistry, Analytical; Materials Science, Characterization & Testing; Spectroscopy SC Chemistry; Materials Science; Spectroscopy GA BX89S UT WOS:000186759900024 ER PT B AU Baca, AG Briggs, RD Johnson, JW Monier, C Allerman, AA Mitchell, CC Wendt, JR Shul, RJ Ren, F Armendariz, MG AF Baca, AG Briggs, RD Johnson, JW Monier, C Allerman, AA Mitchell, CC Wendt, JR Shul, RJ Ren, F Armendariz, MG BE Chang, PC Chu, SNG Buckley, DN TI High performance GaN/AIGaN HEMTs SO STATE-OF-THE-ART PROGRAM ON COMPOUND SEMICONDUCTORS (SOTAPOCS XXXV) SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 35th State-of-the-Art-Program on Compound Semiconductor CY SEP 02-09, 2001 CL SAN FRANCISCO, CA SP Electrochem Soc, Electr Div ID ALGAN/GAN HEMTS; GAN/ALGAN HEMTS; POWER AB GaN HEMT structures with an aluminum concentration of 20% in the AlGaN charge transfer layer have been grown on sapphire substrates by MOCVD. DC current density in excess of 0.8 A/mm has been achieved for HEMTs with gate length ranging from 0.1 mum to 0.5 mum. Maximum transconductance of 207 mS/mm was achieved. From sparameter measurements, f(t) of 65 GHz and f(max) of 85 GHz were extracted. 0.25x150 mum(2) devices yielded a power density of 2.75 W/mm, measured on-wafer at 3GHz with 17 dB gain and 56% power-added efficiency. At 10 GHz, 1.66 W/mm was measured with 10 dB gain and 27% power-added efficiency. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Baca, AG (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 7 TC 0 Z9 0 U1 1 U2 1 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-353-9 J9 ELEC SOC S PY 2001 VL 2001 IS 20 BP 41 EP 46 PG 6 WC Electrochemistry; Engineering, Electrical & Electronic; Optics SC Electrochemistry; Engineering; Optics GA BV99K UT WOS:000180622600006 ER PT B AU Monier, C Baca, AG Chang, PC Newman, F Li, NY Armour, E Briggs, RD Hou, HQ AF Monier, C Baca, AG Chang, PC Newman, F Li, NY Armour, E Briggs, RD Hou, HQ BE Chang, PC Chu, SNG Buckley, DN TI High-speed performance of NpNInGaAsN-based double heterojunction bipolar transistors SO STATE-OF-THE-ART PROGRAM ON COMPOUND SEMICONDUCTORS (SOTAPOCS XXXV) SE ELECTROCHEMICAL SOCIETY SERIES LA English DT Proceedings Paper CT 35th State-of-the-Art-Program on Compound Semiconductor CY SEP 02-09, 2001 CL SAN FRANCISCO, CA SP Electrochem Soc, Electr Div ID 1.3 MU-M; INGAASN AB Improved characteristics are demonstrated from a NpN GaAs-based double heterojunction bipolar transistor (DHBT) using a low band gap InGaAsN material (lattice-matched to GaAs with a band gap energy E-G of 1.2 eV) as the base layer. An improved band-gap engineering design is implemented at both emitter-base and base-collector heterojunctions of this novel GaAs-based HBT platform to overcome the current blocking effect with a resulting useful DC current gain beta of 23. This design allows a significant turn-on voltage reduction of 0.26 V compared to conventional InGaP/GaAs HBTs. The low turn-on voltage V-ON associated with an offset voltage V-OFFSET similar to 0.10 V and a knee voltage V-KNEE similar to 0.35 V provides an initial indication of the promising potential this novel technology can have for reducing power dissipation in GaAs-based transistors. Self-aligned devices with an active emitter area of 3x5 mum(2) exhibit a cut-off frequency f(T) = 32 GHz and a maximum oscillation frequency f(MAX) of 60 GHz. InGaAsN material quality is the limiting factor as low electron mobility and lifetime values in the base compared to GaAs leads to non-optimized base transit time, base sheet resistance, and significant base current compared to InGaP/GaAs HBTs. Nevertheless, these values show InGaAsN to be a strong contender for low-power electronic applications. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Monier, C (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELECTROCHEMICAL SOCIETY INC PI PENNINGTON PA 65 S MAIN ST, PENNINGTON, NJ 08534-2839 USA BN 1-56677-353-9 J9 ELEC SOC S PY 2001 VL 2001 IS 20 BP 62 EP 69 PG 8 WC Electrochemistry; Engineering, Electrical & Electronic; Optics SC Electrochemistry; Engineering; Optics GA BV99K UT WOS:000180622600009 ER PT B AU Nieh, TG Choi, BW Jankowski, AF AF Nieh, TG Choi, BW Jankowski, AF BE Niinomi, M Okabe, T Taleff, EM Lesuer, DR Lippard, HE TI Syntheses and characterization of porous hydroxyapatite and hydroxyapatite coatings SO STRUCTURAL BIOMATERIALS FOR THE 21ST CENTURY LA English DT Proceedings Paper CT Symposium on Structural Biomaterials for the 21st Century CY FEB 11-12, 2001 CL NEW ORLEANS, LA SP SMD, Struct Mat & Titanium Comm, ASM, MSCTS, Corros & Environm Effects Comm ID MECHANICAL-PROPERTIES; PHOSPHATE; HYDROXYLAPATITE; MICROSTRUCTURE; MORPHOLOGY AB A technique is developed to construct bulk hydroxyapatite (HAp) with different cellular structures. The technique involves the initial synthesis of nanocrystalline hydroxyapatite powder from an aqueous solution using water-soluble compounds and then followed by spray drying into agglomerated granules, The granules were further cold pressed and sintered into bulks at elevated temperatures. The sintering behavior of the HAp, granules was characterized and compared with those previously reported. Resulting from the fact that the starting HAp, powders were extremely fine, a relatively low activation energy for sintering was obtained. In the present study, both porous and dense structures were produced by varying powder morphology acid sintering parameters. Porous structures consisting of open cells were constructed. Sintered structures were characterized using scanning electron microscopy and x-ray tomography. In the present paper, hydroxyapatite coatings produced by magnetron sputtering on silicon and titanium substrates will also be presented. The mechanical properties of the coatings were measured using nanoindentation techniques and microstructures examined using transmission electron microscopy. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Nieh, TG (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-350, Livermore, CA 94551 USA. NR 22 TC 0 Z9 0 U1 0 U2 6 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-487-9 PY 2001 BP 203 EP 212 PG 10 WC Materials Science, Biomaterials SC Materials Science GA BS16A UT WOS:000168874700023 ER PT B AU Gray, GT Steif, PS Pollock, TM AF Gray, GT Steif, PS Pollock, TM BE Hemker, KJ Dimiduk, DM Clemens, H Darolia, R Inui, H Larsen, JM Sikka, VK Thomas, M Whittenberger, JD TI Dynamic deformation and damage in cast gamma-TiAl during Taylor cylinder impact: Experiments and model validation SO STRUCTURAL INTERMETALLICS 2001 LA English DT Proceedings Paper CT 3rd International Symposium on Structural Intermetallics (IS SI) CY SEP 23-27, 2001 CL JACKSON HOLE, WY SP Minerals, Met & Mat Soc, Struct Mat Div ID BEHAVIOR AB The dynamic deformation, damage evolution, and cracking in four cast gamma titanium aluminide alloys has been investigated experimentally and theoretically. The purpose of this study was to examine the dynamic constitutive properties of cast TiAl alloys. Using the measured high-strain-rate constitutive properties, the deformation and damage evolution observed in Taylor cylinder experiments was predicted using finite-element modeling. The utility of Taylor cylinders for validation of high-rate constitutive models for intermetallics is detailed. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Gray, GT (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 16 TC 3 Z9 3 U1 0 U2 2 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-511-5 PY 2001 BP 269 EP 277 PG 9 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BT48V UT WOS:000173131100031 ER PT B AU Misra, A Mitchell, TE Sharif, AA Chen, SP Baskes, MI Hoagland, RG AF Misra, A Mitchell, TE Sharif, AA Chen, SP Baskes, MI Hoagland, RG BE Hemker, KJ Dimiduk, DM Clemens, H Darolia, R Inui, H Larsen, JM Sikka, VK Thomas, M Whittenberger, JD TI Yield stress anomalies, dislocation core structures and substitutional alloying in molybdenum disilicide SO STRUCTURAL INTERMETALLICS 2001 LA English DT Proceedings Paper CT 3rd International Symposium on Structural Intermetallics (IS SI) CY SEP 23-27, 2001 CL JACKSON HOLE, WY SP Minerals, Met & Mat Soc, Struct Mat Div ID MOSI2 SINGLE-CRYSTALS; SOLIDIFIED MOSI2-BASED ALLOYS; SMALL ALUMINUM ADDITIONS; PLASTIC-DEFORMATION; MECHANICAL-PROPERTIES; TEMPERATURE; MICROSTRUCTURE; COMPOSITES; SILICIDE AB A brief overview of the temperature dependence of yield strength for the different slip Systems of MoSi2 is presented and mechanisms for the yield stress anomaly are discussed. Recent results on the atomistic simulation of the dislocation core structures and mobility are presented next. Finally, we present experimental results on substitutional alloying of polycrystalline MoSi2 with 1-2 at.% Re, Nb and Al. Re resulted in an order of magnitude increase in compressive strength at 1600 degreesC, Al caused solution softening at near-ambient temperatures, and Nb caused softening at low temperatures and hardening at high temperatures. The quaternary MoSi2-Re-Al alloys showed strengthening at elevated temperatures and reduction in flow stress with enhanced plasticity at near-ambient temperatures, The mechanisms of solution hardening and softening are discussed using insight from transmission electron microscopy observations of the dislocation substructures and atomistic simulation results. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Mat Sci & Technol, MS K765, Los Alamos, NM 87545 USA. RI Hoagland, Richard/G-9821-2012; Misra, Amit/H-1087-2012 NR 40 TC 0 Z9 0 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-511-5 PY 2001 BP 449 EP 456 PG 8 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BT48V UT WOS:000173131100051 ER PT B AU Schneibel, JH Easton, DS Choe, H Ritchie, RO AF Schneibel, JH Easton, DS Choe, H Ritchie, RO BE Hemker, KJ Dimiduk, DM Clemens, H Darolia, R Inui, H Larsen, JM Sikka, VK Thomas, M Whittenberger, JD TI Fracture toughness, creep strength and oxidation resistance of Mo-Mo3Si-Mo(5)Sib(2) molybdenum silicides SO STRUCTURAL INTERMETALLICS 2001 LA English DT Proceedings Paper CT 3rd International Symposium on Structural Intermetallics (IS SI) CY SEP 23-27, 2001 CL JACKSON HOLE, WY SP Minerals, Met & Mat Soc, Struct Mat Div ID MECHANICAL-PROPERTIES; BEHAVIOR; MO; COMPOSITES; BORON AB Alloys consisting of different ratios of the phases alpha-Mo, Mo3Si, and Mo5SiB2 ("T2") were fabricated by ingot and powder metallurgy. Screening tests were carried out to assess their oxidation resistance. A powder-metallurgically processed alloy with the composition Mo-16.8Si-8.4B (at. %) exhibited a weight loss of only 5 mg/cm(2) after I day at 1300degreesC in air. Depending on the measurement technique, a cast and annealed alloy with the composition Mo-12Si-8.5B exhibited a room temperature fracture toughness ranging from 8 to 10 MPa m(1/2). Relatively flat R-curves suggest that the crack growth resistance at room temperature was not primarily determined by conventional ductile-phase toughening but rather by crack-trapping ahead of the crack tip (intrinsic toughening). The creep properties of Mo-12Si-8.5B were determined from slow (10(-s) s(-1)) compression experiments between 1200 and 1400degreesC. An empirical constitutive equation was derived. Whereas partial substitution of Mo with 19.5 at. % W improved the creep strength only slightly, the same amount of Nb almost doubled the creep strength. Since W and Nb do not change the 3-phase structure of the alloys, the increase in the creep strength is due to solid solution strengthening in one or more of the phases. Using differently processed materials with the nominal composition Mo-16.8Si-8.4B, it is shown that the microstructure can also have a pronounced influence on the creep strength. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Schneibel, JH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 16 TC 4 Z9 4 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-511-5 PY 2001 BP 801 EP 809 PG 9 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BT48V UT WOS:000173131100090 ER PT B AU Tiegs, TN Schroeder, JL Menchhofer, PA Montgomery, FC Barker, DL Goranson, F Wittmer, DE AF Tiegs, TN Schroeder, JL Menchhofer, PA Montgomery, FC Barker, DL Goranson, F Wittmer, DE BE Hemker, KJ Dimiduk, DM Clemens, H Darolia, R Inui, H Larsen, JM Sikka, VK Thomas, M Whittenberger, JD TI Processing and properties of TiC-Ni3Al composites SO STRUCTURAL INTERMETALLICS 2001 LA English DT Proceedings Paper CT 3rd International Symposium on Structural Intermetallics (IS SI) CY SEP 23-27, 2001 CL JACKSON HOLE, WY SP Minerals, Met & Mat Soc, Struct Mat Div ID MEASURING FRACTURE-TOUGHNESS; INDENTATION TECHNIQUES AB TiC-Ni3Al composites have properties suitable for engine applications. Powder compacts with binder contents from 30-50 vol. % were fabricated by pressureless sintering under vacuum followed by low gas pressure isostatic pressing. The final microstructure consisted of a 'core-rim' structure with TiC cores surrounded by Ti(Cr,Mo,W)C rims. Room temperature flexural strengths ranged from >800 MPa up to 1150 MPa. These strengths were retained or actually increased up to temperatures of 500degreesC. The fracture toughness values were all >12 MParootm and as high as 27 MParootm at Ni3Al contents from 30 to 50 vol. %, respectively. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Tiegs, TN (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Schroeder, Jeremy/J-8909-2013; Menchhofer, Paul/E-1529-2017 OI Menchhofer, Paul/0000-0001-9475-314X NR 13 TC 1 Z9 1 U1 2 U2 5 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-511-5 PY 2001 BP 811 EP 818 PG 8 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BT48V UT WOS:000173131100091 ER PT S AU Kelly, RE AF Kelly, RE BE Nguyen, C TI Underground structure detection by surface magnetic gradient measurements SO SUBSURFACE AND SURFACE SENSING TECHNOLOGIES AND APPLICATIONS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 3rd International Conference on Subsurface and Surface Sensing Technologies and Applications CY JUL 30-AUG 01, 2001 CL SAN DIEGO, CA SP SPIE DE underground detection; electromagnetic theory; magnetic induction; tunnels; underground structures; imaging AB This problem involves magnetic induction methods to locate and determine the depth of a subsurface line source of magnetic field. The origin of the field may be self-generated or induced by a surface transmitter. The experimental method requires measuring the horizontal gradient of either the vertical or horizontal component of the field rather than the field itself so as to increase signal to noise ratio. A mathematical outline is presented and experimental results are discussed. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kelly, RE (reprint author), Los Alamos Natl Lab, POB 1663,MS D410, Los Alamos, NM 87545 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4205-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4491 BP 367 EP 374 DI 10.1117/12.450182 PG 8 WC Optics SC Optics GA BT77X UT WOS:000174013900039 ER PT S AU Lafon, R Chaloupka, JL Sheehy, B Dimauro, LF Paul, PM Agostini, P Kulander, KC AF Lafon, R Chaloupka, JL Sheehy, B Dimauro, LF Paul, PM Agostini, P Kulander, KC BE Piraux, B Rzazewski, K TI Energy distribution of two-electron ionization of helium in an intense laser field SO SUPER-INTENSE LASER-ATOM PHYSICS SE NATO Science Series II-Mathematics Physics and Chemistry LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Super-Intense Laser-Atom Physics CY SEP 24-30, 2000 CL HAN SUR LESSE, BELGIUM SP NATO Sci Affairs Div ID NONSEQUENTIAL DOUBLE-IONIZATION; MULTIPHOTON IONIZATION; MOMENTUM DISTRIBUTIONS; TUNNELING IONIZATION; IMPACT IONIZATION; CROSS-SECTIONS; IONS; DYNAMICS; SINGLE; LIMIT C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Lafon, R (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 1568-2609 BN 0-7923-6863-0 J9 NATO SCI SER II-MATH PY 2001 VL 12 BP 3 EP 13 PG 11 WC Physics, Atomic, Molecular & Chemical SC Physics GA BS18R UT WOS:000169000900001 ER PT B AU Ditmire, T Zweiback, J Cowan, TE Hays, G Wharton, KB Crane, JK Wilks, SC Smith, RA Donnelly, TD Rust, M Weiner, I Allen, M AF Ditmire, T Zweiback, J Cowan, TE Hays, G Wharton, KB Crane, JK Wilks, SC Smith, RA Donnelly, TD Rust, M Weiner, I Allen, M BE Piraux, B Rzazewski, K TI Nuclear fusion in gases of deuterium clusters and hot electron generation in droplet sprays under irradiation with an intense femtosecond laser SO SUPER-INTENSE LASER-ATOM PHYSICS SE NATO SCIENCE SERIES, SERIES II: MATHEMATICS, PHYSICS AND CHEMISTRY LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Super-Intense Laser-Atom Physics CY SEP 24-30, 2000 CL HAN SUR LESSE, BELGIUM SP NATO Sci Affairs Div ID X-RAY GENERATION; ATOMIC CLUSTERS; ABSORPTION; EXPLOSIONS; PULSES; TEMPERATURE; EMISSION; PRESSURE; PLASMAS C1 Univ Calif Lawrence Livermore Natl Lab, Laser Program, Livermore, CA 94550 USA. RP Ditmire, T (reprint author), Univ Calif Lawrence Livermore Natl Lab, Laser Program, Livermore, CA 94550 USA. RI Cowan, Thomas/A-8713-2011 OI Cowan, Thomas/0000-0002-5845-000X NR 23 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 0-7923-6863-0 J9 NATO SCI SER II MATH PY 2001 VL 12 BP 205 EP 218 PG 14 WC Physics, Atomic, Molecular & Chemical SC Physics GA BS18R UT WOS:000169000900018 ER PT B AU Williamson, RL Shelmidine, GJ AF Williamson, RL Shelmidine, GJ BE Loria, EA TI Current paths during vacuum arc remelting of Alloy 718 SO SUPERALLOYS 718, 625, 706 AND VARIOUS DERIVATIVES LA English DT Proceedings Paper CT 5th International Symposium on Superalloys 718, 625, 706 and Various Derivatives CY JUN 17-20, 2001 CL PITTSBURGH, PA SP TMS, Struct Mat Div, ASM Int, Natl Assoc Corros Engineers, Nickel Dev Inst AB Measurements of crucible voltage and temperature profiles were made during steady-state vacuum are remelting of a 0.435 m diameter Alloy 718 electrode into 0.540 m diameter ingot in a coaxial furnace. The results are used to estimate the amount of current passing through the ingot/stool contact zone (I-is) and the length of the ingot/wall contact zone (hi,). The estimates of I-is varied linearly from similar to 1000 A to similar to 800 A over a range of ingot lengths extending from 0.8 to 1.6 m. h(iw) was determined to be very small, <0.1 m. Additionally, the fraction of current passing through the top ingot surface was estimated to be between 0.5 and 0.8 from the data and physical arguments. This information is required to accurately model the pool shape and fluid flows in the liquid metal pool atop the ingot. C1 Sandia Natl Labs, Liquid Met Proc Lab, Albuquerque, NM 87185 USA. RP Williamson, RL (reprint author), Sandia Natl Labs, Liquid Met Proc Lab, POB 5800, Albuquerque, NM 87185 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-510-7 PY 2001 BP 91 EP 102 PG 12 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BS41C UT WOS:000169763200009 ER PT B AU Miller, MK Babu, SS AF Miller, MK Babu, SS BE Loria, EA TI Atomic level characterization of precipitation in Alloy 718 SO SUPERALLOYS 718, 625, 706 AND VARIOUS DERIVATIVES LA English DT Proceedings Paper CT 5th International Symposium on Superalloys 718, 625, 706 and Various Derivatives CY JUN 17-20, 2001 CL PITTSBURGH, PA SP TMS, Struct Mat Div, ASM Int, Natl Assoc Corros Engineers, Nickel Dev Inst ID PROBE AB Alloy 718 derives its good mechanical properties from a fine dispersion of ordered precipitates in a face centered cubic matrix. However, the precise nature of these precipitates has only been resolved recently through atomic level characterization of the compositions of these precipitates in a three-dimensional atom probe. Atom probe tomography has revealed that these fine (< similar to 20 nm diameter) precipitates generally consist of two distinct types of regions that are enriched either in niobium or in aluminum and titanium that are characteristic of the gamma" and gamma' phases, respectively. Reasonable agreement may be achieved between atom probe measurements and thermodynamic predictions of the compositions of these phases when additional microstructural information is taken into account and absent phases are suppressed in thermodynamic calculations. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Miller, MK (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Babu, Sudarsanam/D-1694-2010 OI Babu, Sudarsanam/0000-0002-3531-2579 NR 14 TC 5 Z9 5 U1 0 U2 1 PU MINERALS, METALS & MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086-7514 USA BN 0-87339-510-7 PY 2001 BP 357 EP 365 PG 9 WC Metallurgy & Metallurgical Engineering; Materials Science, Coatings & Films SC Metallurgy & Metallurgical Engineering; Materials Science GA BS41C UT WOS:000169763200035 ER PT S AU Dougherty, LM Robertson, IM Vetrano, JS Bruemmer, SM AF Dougherty, LM Robertson, IM Vetrano, JS Bruemmer, SM BE Chandra, N TI A microstructural study of the effect of particle aging on dynamic continuous recrystallization in Al-4Mg-0.3Sc SO SUPERPLASTICITY IN ADVANCED MATERIALS, ICSAM-2000 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Superplasticity in Advanced Materials (ICSAM-2000) CY AUG 01-04, 2000 CL ORLANDO, FLORIDA SP Florida State Univ, Adv Mech & Mat Lab, Dept Mech Engn, FAMU FSU Coll Engn, MSC Software, Oakridge Natl Lab DE Al-Mg-Sc alloy; aluminium; continuous; dynamic; in-situ TEM; orientation imaging microscopy OIM; recrystallization; superplasticity; TEM; transmission electron microscopy TEM AB Tensile specimens of an Al-4Mg-0.3Sc alloy in the peak-aged (8 hours at 553 K) and the over-aged (96 hours at 623 K) conditions, cold-rolled to a 70% reduction, exhibited dynamic continuous recrystallization during superplastic testing at 733 K and a strain rate of 10(-3)s(-1). Although the removal of subboundaries and the development of an equiaxed grain structure occurred more rapidly in the over-aged alloy, there was no discernible difference in the microstructures as observed in the transmission electron microscope (TEM). The fundamental mechanisms controling dynamic continuous recrystallization have been studied by a combination of post-mortem examinations of the developing microstructure frozen at several points during the forming process and dynamic, high-temperature, deformation experiments performed in the TEM. The latter experiments provide direct observation at high spatial resolution of the operating mechanisms and have shown migration, pinning, disintegration and annihilation of subboundaries as well as the incorporation of dislocations into grain boundaries as they occur in real time. C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Dougherty, LM (reprint author), Univ Illinois, Dept Mat Sci & Engn, 1304 W Green St, Urbana, IL 61801 USA. NR 7 TC 1 Z9 1 U1 0 U2 2 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-874-5 J9 MATER SCI FORUM PY 2001 VL 357-3 BP 93 EP 98 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA BS10P UT WOS:000168667100013 ER PT S AU Dutkiewicz, J Kusnierz, J Nieh, TG AF Dutkiewicz, J Kusnierz, J Nieh, TG BE Chandra, N TI Development of superplastic AlCuAgMgZr alloys for easy forming SO SUPERPLASTICITY IN ADVANCED MATERIALS, ICSAM-2000 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Superplasticity in Advanced Materials (ICSAM-2000) CY AUG 01-04, 2000 CL ORLANDO, FLORIDA SP Florida State Univ, Adv Mech & Mat Lab, Dept Mech Engn, FAMU FSU Coll Engn, MSC Software, Oakridge Natl Lab DE AlCuAgMgZr alloys; grain refinement; superplastic deformation AB Two aluminium alloys containing up to 6% Cu, 0.8% Ag, 0.7 % Mg and 0.4 % Zr (all in wt %) were continuously cast and hot rolled at 673 K. Thermomechanical treatment involving particle stimulated nucleation (PSN) process was used in order to obtain fine grain size. The microstructure studies after this treatment revealed the presence of subgrains of 0.5-2 mum in size with a misorientation of 3 - 15 degrees. In spite of the presence of zirconium rich and copper rich particles the grain growth up to 10-20 mum was observed after annealing at temperatures above 673K. This was also observed in samples deformed at the temperature of 673K. It affected the superplastic deformation properties of the investigated alloys at higher temperatures in a negative way. The superplastic behaviour was characterised by the m value, which was determined by step strain - rate change tests. The tests were conducted at a slow initial strain rate, which increased stepwise to high constant strain rates. The highest m value obtained approached 0.7 for the lowest temperature (623K) and the strain rates (10(-3) - 10(-4) s(-1)). A value close to 0.5 was observed for temperatures 623-673K and the same strain rates. The lowest m values were found for temperatures T> 623K and higher strain rates. Structure studies of the superplastically deformed samples revealed grain growth and presence of cavities after elongation of a few hundreds percent. Presence of dislocations within grains indicates the participation of the crystallographic slip in the superplastic deformation at 673K. C1 Polish Acad Sci, Inst Met & Mat Sci, PL-30059 Krakow, Poland. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Dutkiewicz, J (reprint author), Polish Acad Sci, Inst Met & Mat Sci, Ul Reymonta 25, PL-30059 Krakow, Poland. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 8 TC 1 Z9 1 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-874-5 J9 MATER SCI FORUM PY 2001 VL 357-3 BP 111 EP 116 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA BS10P UT WOS:000168667100016 ER PT S AU Namilae, S Shet, C Chandra, N Nieh, TG AF Namilae, S Shet, C Chandra, N Nieh, TG BE Chandra, N TI Atomistic simulation of the effect of trace elements on grain boundary of aluminum SO SUPERPLASTICITY IN ADVANCED MATERIALS, ICSAM-2000 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Superplasticity in Advanced Materials (ICSAM-2000) CY AUG 01-04, 2000 CL ORLANDO, FLORIDA SP Florida State Univ, Adv Mech & Mat Lab, Dept Mech Engn, FAMU FSU Coll Engn, MSC Software, Oakridge Natl Lab DE grain boundary energy; hydrostatic stress; segregation ID SEGREGATION; AL AB Molecular statics simulations are used in conjunction with the Embedded Atom Method to study the segregation tendency of magnesium and the effect of doping on aluminum symmetric tilt grain boundaries (STGB). It is observed that a state of hydrostatic stress exists predominantly near the grain boundary and influences the segregation energy of magnesium. The origin of hydrostatic stress is explained in terms of local geometrical arrangement of atoms at the grain boundary. The energy of a given grain boundary is found to increase with addition of Mg atoms and the increase depends on the normal distance of the atom from the grain boundary. C1 Florida State Univ, FAMU FSU Coll Engn, Dept Mech Engn, Tallahassee, FL 32310 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Namilae, S (reprint author), Florida State Univ, FAMU FSU Coll Engn, Dept Mech Engn, Tallahassee, FL 32310 USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 11 TC 0 Z9 0 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-874-5 J9 MATER SCI FORUM PY 2001 VL 357-3 BP 387 EP 392 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA BS10P UT WOS:000168667100058 ER PT S AU Herling, DR Smith, MT AF Herling, DR Smith, MT BE Chandra, N TI Improvements in superplastic performance of commercial AA5083 aluminium processed by equal channel angular extrusion SO SUPERPLASTICITY IN ADVANCED MATERIALS, ICSAM-2000 SE MATERIALS SCIENCE FORUM LA English DT Article; Proceedings Paper CT International Conference on Superplasticity in Advanced Materials (ICSAM-2000) CY AUG 01-04, 2000 CL ORLANDO, FLORIDA SP Florida State Univ, Adv Mech & Mat Lab, Dept Mech Engn, FAMU FSU Coll Engn, MSC Software, Oakridge Natl Lab DE aluminium alloy 5083; ECAE; equal-channel-angular-extrusion; SPF; superplasticity ID MECHANICAL-PROPERTIES AB An improvement in superplastic performance, as measured by elongation to failure, was achieved in an AA5083 aluminum alloy. Equal channel angular extrusion (ECAE) processing was performed on commercially available hot rolled AA5083 material, in order to refine the microstructure to achieve superplastic characteristics. The ECAE process offered several potential advantages in the processing of an SPF-grade aluminum alloy. The first was the ability to introduce a high level of energy into the structure through localized shearing, which developed a well-defined sub-grain structure and ultimately a refined microstructure upon recrystallization. Secondly, with ECAE there is the unique ability to achieve the desirable microstructure in bulk form without reducing the dimensions of the starting material, as is the case in conventional roll processing of SPF sheet materials. Total elongation of >350% was measured at a temperature of 550 degreesC and strain rate of 5x10(-4). This was an increase in elongation of over 150% compared to the same material processed by convention thermal mechanical processing (TMP) techniques, designed to produce a fine grain microstructure in sheet material. Past work on the same commercial AA5083 material using an appropriate TMP schedule, revealed <200% elongation was achievable at the same temperature and strain rate. Through conventional thermal mechanical processing (a series of heat treatments and hot and cold rolling steps), the minimum grain size achieved was typically limited to 10 m, but with ECAE an average grain size <2 m was produced, after the recovery heat treatment step. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Herling, DR (reprint author), Pacific NW Natl Lab, 902 Battelle Blvd,MSIN P8-35, Richland, WA 99352 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU TRANS TECH PUBLICATIONS LTD PI ZURICH-UETIKON PA BRANDRAIN 6, CH-8707 ZURICH-UETIKON, SWITZERLAND SN 0255-5476 BN 0-87849-874-5 J9 MATER SCI FORUM PY 2001 VL 357-3 BP 465 EP 470 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA BS10P UT WOS:000168667100070 ER PT J AU Lamb, JD Nelson, EG Macdonald, DM Levitskaia, TG AF Lamb, JD Nelson, EG Macdonald, DM Levitskaia, TG TI Calorimetric investigation of the complexation of didodecylcalix[4]arene-crown-6 with alkali metal and ammonium cations in acetonitrile SO SUPRAMOLECULAR CHEMISTRY LA English DT Article DE calorimetry; calixarene; crown; metal ion complexation; cesium separation ID BINDING-PROPERTIES; CRYSTAL-STRUCTURES; CESIUM; EXTRACTION; CONFORMATION; SIMULATIONS; SELECTIVITY; IONOPHORES; CHLOROFORM; INTERFACE AB The Cs+ selectivity of some calix-crown ligands makes them excellent candidates for use in separation systems such as liquid membranes. Separation performance can be understood and predicted from thermodynamic data for cation complexation. We have therefore determined the log K, DeltaH and DeltaS for the interaction of Na+, K+, Rb+, Cs+ and NH4+ with didodecyl-calix[4]arene-crown-6 in acetonitrile at 25 degreesC by titration calorimetry. The ligand is strongly selective for Cs+, and the selectivity trend results entirely from the enthalpy contribution, with entropy effects opposing the trend. These results are discussed in light of some corresponding data obtained by other researchers with similar ligands. C1 Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84601 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Lamb, JD (reprint author), Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84601 USA. NR 18 TC 0 Z9 0 U1 0 U2 3 PU GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP PI PHILADELPHIA PA 325 CHESTNUT ST, 8TH FL, PHILADELPHIA, PA 19106 USA SN 1061-0278 J9 SUPRAMOL CHEM JI Supramol. Chem. PY 2001 VL 13 IS 2 BP 349 EP 355 DI 10.1080/10610270108027489 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 457KK UT WOS:000170136000010 ER PT J AU Agarwal, A Dahotre, NB Riester, L Sudarshan, TS AF Agarwal, A Dahotre, NB Riester, L Sudarshan, TS TI Elastic modulus of pulse electrode surface deposited composite boride coating using nanoindentation SO SURFACE ENGINEERING LA English DT Article ID MECHANICAL-PROPERTIES; EVOLUTION; STEEL AB A composite titanium diboride coating has been deposited on AISI 1010 steel using a pulse electrode surfacing (PES) technique. Such a boride coating processed by the PES process is ultrafine grained, hard, tough, and free from cracks. An attempt has been made to evaluate the elastic modulus of the composite boride coating using the nanoindentation technique. The experimental elastic modulus of the coating was found to be 347 GPa. The computed elastic modulus value (318.4 GPa) is lower than the experimental elastic modulus (347 GPa) as the latter includes the effect of metastable phase formation such as FexBy and TiaBb in minor amounts. (C) 2001 IoM Communications Ltd. C1 Plasma Proc Inc, Huntsville, AL 35811 USA. Univ Tennessee, Ctr Laser Applicat, Dept Mat Sci & Engn, Knoxville, TN 37831 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Mat Modificat Inc, Fairfax, VA 22031 USA. RP Agarwal, A (reprint author), Plasma Proc Inc, 4914 D Moores Mill Rd, Huntsville, AL 35811 USA. NR 13 TC 4 Z9 4 U1 1 U2 1 PU MANEY PUBLISHING PI LEEDS PA HUDSON RD, LEEDS LS9 7DL, ENGLAND SN 0267-0844 J9 SURF ENG JI Surf. Eng. PY 2001 VL 17 IS 6 BP 495 EP 497 DI 10.1179/026708401322911428 PG 3 WC Materials Science, Coatings & Films SC Materials Science GA 518QM UT WOS:000173679400010 ER PT S AU Zhang, Z Kameda, J Swanson, AH Sakurai, S Sato, M AF Zhang, Z Kameda, J Swanson, AH Sakurai, S Sato, M BE Meng, WJ Kumar, A Doll, GL Cheng, YT Veprek, S Chung, YW TI Effects of porosity and thermal ageing on in-plane cracking behavior of thermal barrier coatings SO SURFACE ENGINEERING 2001 - FUNDAMENTALS AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Advances in Surface Engineering - Fundamentals and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc AB This paper describes the effects of porosity and thermal ageing at 950degreesC for 4000 hr. in air on in-plane cracking behavior of plasma-sprayed thermal barrier coating (TBC) made up of 8 % yittria-stabilized zirconia. The in-plane TBC cracking was analyzed by a protruded TBC bend testing technique together with finite element stress analysis. As-deposited and aged TBC protruded specimens showed a large variation of porosity depending on the location of specimen extraction. The critical local tensile stress (sigma*) necessary for the initiation of in-plane cracks for each specimen with different porosity was determined using elastic moduli (E) estimated from the porosity dependence of E. The sigma* for in-plane cracking of the as-deposited TBC initially increased with increasing porosity and showed a peak when the porosity reached 0.23. It was shown that in-plane cracking at the interface of TBC and thermally grown oxides required much higher sigma* than that at the interface of TBC and bond coatings. The thermal ageing led to a slight increase in sigma* for away-from-interfacial TBC cracking. The dependence of in-plane TBC cracking behavior on the porosity is discussed in terms of effective critical stress via the Griffith criterion for porous materials. C1 Iowa State Univ, Ames Lab, Ames, IA USA. RP Zhang, Z (reprint author), Iowa State Univ, Ames Lab, Ames, IA USA. NR 14 TC 0 Z9 0 U1 1 U2 2 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-633-8 J9 MATER RES SOC SYMP P PY 2001 VL 697 BP 95 EP 100 PG 6 WC Materials Science, Coatings & Films SC Materials Science GA BV23W UT WOS:000178303600015 ER PT S AU Zeng, Z Natesan, K AF Zeng, Z Natesan, K BE Meng, WJ Kumar, A Doll, GL Cheng, YT Veprek, S Chung, YW TI Fabrication of CaO insulator coatings by MOCVD for application in fusion reactor blankets SO SURFACE ENGINEERING 2001 - FUNDAMENTALS AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Advances in Surface Engineering - Fundamentals and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc AB The liquid lithium blanket for fusion reactors requires an electrically insulating coating on the duct to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Calcium oxide (CaO) is a good candidate for the coating material because it is an excellent electrical insulator and it is stable in a liquid lithium environment. In this paper, details are presented on metalorganic chemical-vapor deposition method that was used to fabricate the CaO coating. Composition and phase analyses of the coating were performed by energy dispersive X-ray analysis and X-ray diffraction. Scanning electron microscopy images show that the coating did not crack after several thermal cycles from room temperature to 715degreesC. The resistance of the coating is high enough for an insulating coating on the liquid lithium blanket of fusion reactors. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Zeng, Z (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-633-8 J9 MATER RES SOC SYMP P PY 2001 VL 697 BP 127 EP 132 PG 6 WC Materials Science, Coatings & Films SC Materials Science GA BV23W UT WOS:000178303600019 ER PT S AU Park, JH Natesan, K Smith, DL AF Park, JH Natesan, K Smith, DL BE Meng, WJ Kumar, A Doll, GL Cheng, YT Veprek, S Chung, YW TI Calcium oxide coating on vanadium alloys in liquid lithium SO SURFACE ENGINEERING 2001 - FUNDAMENTALS AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Advances in Surface Engineering - Fundamentals and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc AB We have fabricated CaO coatings on vanadium metal and various vanadium alloys (V-10Cr, V-1Ti, V-4Cr-4Ti, and V-5Cr-5Ti), for use in liquid metal blankets of fusion reactors. Initially, by monitoring weight change as a function of time, oxygen was charged into the vanadium alloys (rectangular sample, 2 x 1 x 0.1 cm) at 710degreesC by flowing Ar-O-2 gas. Oxygen-charged samples were exposed in 2.8 at.% Ca-Li at temperatures of 600 and 700degreesC for times between 50 and 120 h. The thickness of the in-situ-formed CaO was 13 to 30 mum in the experimental conditions. Thicker CaO films were formed at higher oxygen contents and 700degreesC, while thinner CaO films were formed at lower oxygen contents and 600degreesC. The data show promise for in-situ formation of CaO layers on V alloys for the fusion blanket application. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Park, JH (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-633-8 J9 MATER RES SOC SYMP P PY 2001 VL 697 BP 141 EP 146 PG 6 WC Materials Science, Coatings & Films SC Materials Science GA BV23W UT WOS:000178303600021 ER PT S AU Muhlstein, CL Stach, EA Ritchie, RO AF Muhlstein, CL Stach, EA Ritchie, RO BE Meng, WJ Kumar, A Doll, GL Cheng, YT Veprek, S Chung, YW TI On the mechanism of fatigue in micron-scale structural films of polycrystalline silicon SO SURFACE ENGINEERING 2001 - FUNDAMENTALS AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Advances in Surface Engineering - Fundamentals and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc ID SINGLE-CRYSTAL SILICON; CRACK-GROWTH; FRACTURE; MEMS AB 2-mum thick structural films of polycrystalline silicon are shown to display "metal-like" stress-life fatigue behavior in room air, with failures occurring after >10(11) cycles at stresses as low as half the fracture strength. Using in situ measurements of the specimen compliance and transmission electron microscopy to characterize such damage, the mechanism of thin-film silicon fatigue is deduced to be sequential oxidation and moisture-assisted cracking in the native SiO2 layer. This mechanism can also occur in bulk silicon but it is only relevant in thin films where the critical crack size for catastrophic failure can be exceeded within the oxide layer. The fatigue susceptibility of thin-film silicon is shown to be suppressed by alkene-based self-assembled monolayer coatings that prevent the formation of the native oxide. C1 Lawrence Berkeley Natl Lab, Mat Sci Div, Berkeley, CA 94720 USA. RP Muhlstein, CL (reprint author), Lawrence Berkeley Natl Lab, Mat Sci Div, Berkeley, CA 94720 USA. RI Stach, Eric/D-8545-2011 OI Stach, Eric/0000-0002-3366-2153 NR 22 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-633-8 J9 MATER RES SOC SYMP P PY 2001 VL 697 BP 227 EP 234 PG 8 WC Materials Science, Coatings & Films SC Materials Science GA BV23W UT WOS:000178303600034 ER PT S AU Erdemir, A AF Erdemir, A BE Meng, WJ Kumar, A Doll, GL Cheng, YT Veprek, S Chung, YW TI Superlubricity and wearless sliding in diamondlike carbon films SO SURFACE ENGINEERING 2001 - FUNDAMENTALS AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Advances in Surface Engineering - Fundamentals and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc ID TRIBOLOGICAL PROPERTIES; SUPERLOW FRICTION; COATINGS; PERFORMANCE; ENVIRONMENT; BEHAVIOR AB Diamondlike carbon (DLC) films have attracted great interest in recent years mainly because of their unusual optical, electrical, mechanical, and tribological properties. Such properties are currently being exploited for a wide range of engineering applications including magnetic hard disks, gears, sliding and roller bearings, scratch resistant glasses, biomedical implants, etc. Systematic studies on carbon-based materials in our laboratory have led to the development of a new class of amorphous DLC films that provide extremely low friction and wear coefficients of 0.001 to 0.005 and 10(-11) to 10(-10) mn(3)/N.m, respectively, when tested in inert-g as or high-vacuum environments. These films were produced in highly hydrogenated gas discharge plasmas by a plasma enhanced chemical vapor deposition process at room temperature. The carbon source gases used in the deposition of these films included methane, acetylene, and ethylene. Tribological studies in our laboratory have established a very close correlation between the composition of the plasmas and the friction and wear coefficients of the resultant DLC films. Specifically, the friction and wear coefficients of DLC films grown in plasmas with higher hydrogen-to-carbon ratios were much lower than films derived from source gases with lower hydrogento-carbon ratios. Fundamental tribological and surface analytical studies have led us to conclude that hydrogen (within the film, as well as on the sliding surfaces) is extremely important for the superlubricity and wearless sliding behavior of these films. Based on these studies, a mechanistic model is proposed to explain the superlow friction and wear properties of the new DLC films. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Erdemir, A (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 34 TC 0 Z9 0 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-633-8 J9 MATER RES SOC SYMP P PY 2001 VL 697 BP 391 EP 403 PG 13 WC Materials Science, Coatings & Films SC Materials Science GA BV23W UT WOS:000178303600059 ER PT J AU Takagi, H Daimon, H Palomares, FJ Fadley, CS AF Takagi, H Daimon, H Palomares, FJ Fadley, CS TI Photoelectron holography analysis of W(110)(1 x 1)-O surface SO SURFACE SCIENCE LA English DT Article DE photoelectron diffraction measurement; photoelectron diffraction; tungsten; low index single crystal surfaces ID MULTIPLE-SCATTERING; DIFFRACTION; ADSORPTION; PATTERNS; OXYGEN; ATOMS AB By applying photoelectron holography analysis to a W(1 1 0)(1 x 1)-O surface, the real space image was reconstructed around the oxygen atoms. The peak positions showed that the oxygen atoms lie within the top layer, which does not contradict the results of the R-factor X-ray photoelectron diffraction analysis of Daimon et al. [Surf. Sci. 408 (1998) 260]. The holographic analysis of the calculated photoelectron diffraction pattern indicated that holographic reconstruction reveals atomic positions up to the third nearest-neighbor scatterers. Our study suggests the possibility that the distance among the adsorbate oxygen atoms is slightly larger than the lattice constant of the substrate. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Osaka Univ, Grad Sch Engn Sci, Dept Phys Sci, Toyonaka, Osaka 560, Japan. Nara Inst Sci & Technol, Grad Sch Mat Sci, Nara 6300101, Japan. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. CSIC, ICMM, E-28049 Madrid, Spain. RP Daimon, H (reprint author), Osaka Univ, Grad Sch Engn Sci, Dept Phys Sci, Toyonaka, Osaka 560, Japan. RI Palomares, Francisco Javier/C-4605-2011 OI Palomares, Francisco Javier/0000-0002-4768-2219 NR 16 TC 5 Z9 5 U1 3 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JAN 1 PY 2001 VL 470 IS 3 BP 189 EP 196 DI 10.1016/S0039-6028(00)00839-6 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 397RP UT WOS:000166709600001 ER PT J AU Overbury, SH Mullins, DR Kundakovic, L AF Overbury, SH Mullins, DR Kundakovic, L TI Enhancement of dissociation by metal-support interaction: reaction of NO on Rh supported by ceria films of controlled oxidation state SO SURFACE SCIENCE LA English DT Article DE cerium; nitrogen oxides; soft X-ray photoelectron spectroscopy; thermal desorption; chemisorption; catalysis ID NITRIC-OXIDE; SYNCHROTRON-RADIATION; RHODIUM CATALYSTS; CO; DESORPTION; KINETICS; SURFACES; RH(111); ADSORPTION; OXYGEN AB Highly oriented thin films of cerium oxide with variable ratio of Ce3+/Ce4+ were grown on Ru(0 0 0 1) single crystal surface and loaded with a fixed, low coverage of Rh. The chemisorption of NO on the resulting model catalyst was studied by soft X-ray photoemission which yielded the relative quantities of N containing species on the surface as a function of temperature, and by thermal desorption which yielded the relative yields of NO and Nz desorbed. It is found that the ability of the reduced Ph clusters to dissociate NO depends upon the oxidation state of the ceria upon which it is deposited, and for highly reduced ceria surfaces effectively 100% of Rh-adsorbed NO dissociates by 350 K. Possible causes of this surprising behavior are discussed. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Overbury, SH (reprint author), Oak Ridge Natl Lab, POB 2008,Bldg 4500 N,MS 6201, Oak Ridge, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 32 TC 16 Z9 16 U1 1 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JAN 1 PY 2001 VL 470 IS 3 BP 243 EP 254 DI 10.1016/S0039-6028(00)00864-5 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 397RP UT WOS:000166709600005 ER PT J AU Kittel, M Polcik, M Terborg, R Hoeft, JT Baumgartel, P Bradshaw, AM Toomes, RL Kang, JH Woodruff, DP Pascal, M Lamont, CLA Rotenberg, E AF Kittel, M Polcik, M Terborg, R Hoeft, JT Baumgartel, P Bradshaw, AM Toomes, RL Kang, JH Woodruff, DP Pascal, M Lamont, CLA Rotenberg, E TI The structure of oxygen on Cu(100) at low and high coverages SO SURFACE SCIENCE LA English DT Article DE surface structure, morphology, roughness, and topography; surface relaxation and reconstruction; copper; oxygen; chemisorption; photoelectron diffraction ID PHOTOELECTRON DIFFRACTION; INDUCED RECONSTRUCTION; ADSORPTION; SURFACE; RESOLUTION; SCATTERING; BEAMLINE; DYNAMICS; CU(110) AB The local adsorption structure of oxygen on Cu(1 0 0) has been studied using O Is scanned-energy mode photoelectron diffraction. A detailed quantitative determination of the structure of the 0.5 ML (root2 x 2 root2)R45 degrees -O ordered phase confirms the missing-row character of this reconstruction and agrees well with earlier structural determinations of this phase by other methods, the adsorbed O atoms lying only approximately 0.1 Angstrom above the outermost Cu layer. At much lower coverages, the results indicate that the O atoms adopt unreconstructed hollow sites at a significantly larger O-Cu layer spacing, but with some form of local disorder. The best fit to these data is achieved with a two-site model involving O atoms at Cu-O layer spacings of 0.41 and 0.70 Angstrom in hollow sites: these two sites (also implied by an earlier electron-energy-loss study) are proposed to be associated with edge and centre positions in very small c(2 x 2) domains as seen in a recent scanning tunnelling microscopy investigation. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. Max Planck Gesell, Fritz Haber Inst, D-14195 Berlin, Germany. Univ Huddersfield, Dept Chem & Biol Sci, Ctr Appl Catalysis, Huddersfield HD1 3DH, W Yorkshire, England. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Woodruff, DP (reprint author), Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. RI Rotenberg, Eli/B-3700-2009 OI Rotenberg, Eli/0000-0002-3979-8844 NR 37 TC 62 Z9 62 U1 1 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JAN 1 PY 2001 VL 470 IS 3 BP 311 EP 324 DI 10.1016/S0039-6028(00)00873-6 PG 14 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 397RP UT WOS:000166709600011 ER PT B AU Costigan, KR Winter, CL Springer, EP Stalker, JR AF Costigan, KR Winter, CL Springer, EP Stalker, JR GP AMS AMS TI Coupled modeling system of the hydrologic cycle within river basins SO SYMPOSIUM ON CLIMATE VARIABILITY, THE OCEANS AND SOCIETAL IMPACTS LA English DT Proceedings Paper CT Symposium on Climate Variability, the Oceans and Societal Impacts CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Costigan, KR (reprint author), Los Alamos Natl Lab, EES-8 Mailstop D401, Los Alamos, NM 87545 USA. RI Springer, Everett/B-6376-2012 OI Springer, Everett/0000-0002-9816-8148 NR 5 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 163 EP 166 PG 4 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA BU98Y UT WOS:000177563900036 ER PT B AU Stalker, JR Costigan, KR Reisner, JM Langley, DL AF Stalker, JR Costigan, KR Reisner, JM Langley, DL GP AMS AMS TI Regional climate modeling of the monsoon season over the Rio Grande basin SO SYMPOSIUM ON PRECIPITATION EXTREMES: PREDICTION, IMPACTS, AND RESPONSES LA English DT Proceedings Paper CT Symposium on Precipitation Extremes - Prediction, Impacts and Responses CY JAN 14-18, 2001 CL ALBUQUERQUE, NM SP Amer Meteorol Soc ID PARAMETERIZATION; RAMS C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Stalker, JR (reprint author), Los Alamos Natl Lab, EES-8,Mail Stop D401, Los Alamos, NM 87545 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOCIETY PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108 USA PY 2001 BP 204 EP 209 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA BV03A UT WOS:000177651600053 ER PT J AU Samet, AV Zakharov, EP Semenov, VV Buchanan, AC Gakh, AA AF Samet, AV Zakharov, EP Semenov, VV Buchanan, AC Gakh, AA TI Synthesis of 4,6-dinitroindole from 2,4,6-trinitrotoluene SO SYNTHETIC COMMUNICATIONS LA English DT Article AB 1-R-4,6-Dinitroindoles 4-6 (R=H, Me, Ts) could be obtained from 2-picrylethanol 1 (readily available from TNT) via selective reduction of or ortho-nitro group by N2H4/FeCl3 and subsequent treatment with TsCl, to yield a key intermediate 3. This intermediate was converted to the above mentioned indoles. C1 Russian Acad Sci, ND Zelinskii Organ Chem Inst, Moscow 117913, Russia. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Samet, AV (reprint author), Russian Acad Sci, ND Zelinskii Organ Chem Inst, Leninsky Prosp 47, Moscow 117913, Russia. NR 10 TC 17 Z9 17 U1 1 U2 3 PU MARCEL DEKKER INC PI NEW YORK PA 270 MADISON AVE, NEW YORK, NY 10016 USA SN 0039-7911 J9 SYNTHETIC COMMUN JI Synth. Commun. PY 2001 VL 31 IS 9 BP 1441 EP 1445 DI 10.1081/SCC-100104054 PG 5 WC Chemistry, Organic SC Chemistry GA 454JV UT WOS:000169970200020 ER PT S AU Kurzeja, RJ Pendergast, MM Villa-Aleman, E Garrett, AJ AF Kurzeja, RJ Pendergast, MM Villa-Aleman, E Garrett, AJ BE Watkins, WR Clement, D Reynolds, WR TI Use of natural bodies of water for IR calibration targets SO TARGETS AND BACKGROUNDS VII: CHARACTERIZATION AND REPRESENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Targets and Backgrounds VII - Characterization and Representation Conference CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE water temperature; skin temperature; MTI ID SEA-SURFACE TEMPERATURE; DIFFERENCE AB Natural bodies of water have several advantages as IR calibration targets in remote sensing. Among these are availability, homogeneity, and accurate knowledge of emissivity. A portable, low-cost, floating apparatus is described for calibration of remote IR sensors to within 0.15 C. The apparatus measures the surface and bulk water temperature as well as the wind speed, direction, temperature, and relative humidity. The apparatus collects data automatically and can be deployed for up to 24 hours. The sources of uncertainty, including the effects of skin temperature and waves are discussed. Data from several field campaigns to calibrate IR bands of DOE's Multi-Spectral Thermal Imager are described along with estimates of error. C1 Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Kurzeja, RJ (reprint author), Westinghouse Savannah River Co, Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4065-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4370 BP 152 EP 158 DI 10.1117/12.440072 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA BT73N UT WOS:000173898200017 ER PT S AU Foy, BR McVey, BD Petrin, RR Tiee, JJ Wilson, C AF Foy, BR McVey, BD Petrin, RR Tiee, JJ Wilson, C BE Watkins, WR Clement, D Reynolds, WR TI Target characterization in 3D using infrared lidar SO TARGETS AND BACKGROUNDS VII: CHARACTERIZATION AND REPRESENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Targets and Backgrounds VII - Characterization and Representation Conference CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE lidar; multispectral imaging; matched-filter analysis; vegetation mapping; target detection ID CO2-LASER WAVELENGTHS; REFLECTANCE; CALIBRATION AB We report examples of the use of a scanning tunable CO2 laser lidar system in the 9-11 pin region to construct images of vegetation and rocks at ranges of up to 5 km from the instrument. Range information is combined with horizontal and vertical distances to yield an image with three spatial dimensions simultaneous with the classification of target type. Object classification is made possible by the distinct spectral signatures of both natural and man-made objects. Several multivariate statistical methods are used to illustrate the degree of discrimination possible among the natural variability of objects in both spectral shape and amplitude. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Foy, BR (reprint author), Los Alamos Natl Lab, POB 1663,MS J567, Los Alamos, NM 87545 USA. NR 15 TC 2 Z9 2 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4065-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4370 BP 181 EP 187 DI 10.1117/12.440075 PG 7 WC Optics; Physics, Applied SC Optics; Physics GA BT73N UT WOS:000173898200020 ER PT B AU McCarthy, JJ Haley, DJ Dixon, BW AF McCarthy, JJ Haley, DJ Dixon, BW BE Kocaoglu, DF Anderson, TR TI Science and technology roadmapping to support project planning SO TECHNOLOGY MANAGEMENT IN THE KNOWLEDGE ERA LA English DT Proceedings Paper CT Portland International Conference on Management of Engineering and Technology (PICMET 01) CY JUL 29-AUG 02, 2001 CL PORTLAND, OR SP Portland State Univ, Dept Engn & Technol Management, Univ Tokyo, ETHZ, Santa Clara Univ, George Mason Univ AB Disciplined science and technology roadmapping provides a framework to coordinate research and development activities with project objectives. This case-history paper describes initial project technology needs identification, assessment and R&D ranking activities supporting characterization of 781 waste tanks requiring a 'hazardous waste determination' or 'verification of empty' decision to meet an Idaho state Voluntary Consent Order. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83401 USA. RP McCarthy, JJ (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83401 USA. NR 6 TC 3 Z9 3 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 1-890843-05-9 PY 2001 BP 637 EP 649 DI 10.1109/PICMET.2001.952278 PG 13 WC Computer Science, Information Systems; Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BU62V UT WOS:000176556100069 ER PT S AU Feng, WC Hay, JR Gardner, MK AF Feng, WC Hay, JR Gardner, MK BE Li, J Luijten, R Park, EK TI MAGNeT: Monitor for application-generated network traffic SO TENTH INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS LA English DT Proceedings Paper CT 10th International Conference on Computer Communications and Networks CY OCT 15-17, 2001 CL PHOENIX, AZ SP Army Res Lab, IBM, Telcordia, Nokia, Avaya, IEEE Communicat Soc AB Over the last decade, network practitioners have focused on monitoring, measuring, and characterizing traffic in the network to gain insight into building critical network components (from the protocol tack to routers and switches to network interface cards). Recent research shows that additional insight can be obtained by monitoring traffic at the application level (i.e., before application-sent traffic is modulated by the protocol stack) rather than in the network (i.e., after it is modulated by the protocol stack). Consequently, this paper describes a Monitor for Application-Generated Network Traffic (MAGNeT) that captures traffic generated by the application rather than traffic In the network. MAGNeT consists or application programs as well as modifications to the standard Linux kernel. Together, these tools provide the capability of monitoring an application's network behavior and protocol state information in production systems. The use of MAGNeT will enable the research community to construct a library of real traces of application-generated traffic from which researchers can more realistically test network protocol designs and theory. MAGNeT can also be used to verify the correct operation of protocol enhancements and to troubleshoot and tune protocol implementations. C1 Los Alamos Natl Lab, Comp & Computat Sci Div, Los Alamos, NM 87545 USA. RP Feng, WC (reprint author), Los Alamos Natl Lab, Comp & Computat Sci Div, Los Alamos, NM 87545 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-2055 BN 0-7803-7128-3 J9 IEEE IC COMP COM NET PY 2001 BP 110 EP 115 DI 10.1109/ICCCN.2001.956227 PG 6 WC Computer Science, Information Systems; Telecommunications SC Computer Science; Telecommunications GA BT35E UT WOS:000172717000017 ER PT S AU Weigle, E Feng, WC AF Weigle, E Feng, WC BE Li, J Luijten, R Park, EK TI Dynamic right-sizing: A simulation study SO TENTH INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON COMPUTER COMMUNICATIONS AND NETWORKS LA English DT Proceedings Paper CT 10th International Conference on Computer Communications and Networks CY OCT 15-17, 2001 CL PHOENIX, AZ SP Army Res Lab, IBM, Telcordia, Nokia, Avaya, IEEE Communicat Soc DE dynamic right-sizing; high-performance networking; TCP; flow control; wide-area network AB Virtually all network applications requiring reliable end-to-end communication depend on TCP. Unfortunately, the performance of any stock TCP is abysmal over wide-area networks (WANs) and even over local-area networks (LANs) with very high-bandwidth links. Currently, network researchers manually optimize TCP buffer sizes to achieve acceptable performance over a given connection. Unfortunately, this manual optimization requires changes to the kernel on both end hosts involved in the network connection (changes that are only effective for connections between these two hosts). Furthermore, because two administrative domains must be coordinated to perform this optimization, this process can be tedious and time consuming. To address these problems, this paper illustrates the benefits of a new technique called dynamic right-sizing. This technique dynamically and automatically determines the best buffer size, and hence flow-control window size in TCP. Our simulation study shows that dynamic right-sizing can improve the performance of flows by two orders of magnitude over stock TCP implementations that have static flow-control windows. C1 Los Alamos Natl Lab, RADIANT, Los Alamos, NM 87545 USA. RP Weigle, E (reprint author), Los Alamos Natl Lab, RADIANT, POB 1663, Los Alamos, NM 87545 USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-2055 BN 0-7803-7128-3 J9 IEEE IC COMP COM NET PY 2001 BP 152 EP 158 DI 10.1109/ICCCN.2001.956233 PG 7 WC Computer Science, Information Systems; Telecommunications SC Computer Science; Telecommunications GA BT35E UT WOS:000172717000023 ER PT J AU Quillen, C AF Quillen, Chris TI Terrorism with Weapons of Mass Destruction: The Congressional Response SO TERRORISM AND POLITICAL VIOLENCE LA English DT Article AB The proliferation of weapons of mass destruction (WMD) and the rise in increasingly violent terrorism have coincided this decade to spur many governments to action. This article explores how the U.S. Congress has reacted to this new threat to national security in its attempts to combat both proliferation and terrorism. It recounts the evolution of the congressional response from borderline apathy to intense concern and concludes by demonstrating Congress's desire to focus more on the threat of domestic terrorism as opposed to that of international proliferation. C1 [Quillen, Chris] Oak Ridge Inst Sci & Educ, Natl Secur Program, Oak Ridge, TN USA. RP Quillen, C (reprint author), Georgetown Univ, Natl Secur Studies Program, Washington, DC 20057 USA. NR 16 TC 1 Z9 1 U1 0 U2 0 PU ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXFORDSHIRE, ENGLAND SN 0954-6553 J9 TERROR POLIT VIOLENC JI Terror. Polit. Violence PY 2001 VL 13 IS 1 BP 47 EP 65 DI 10.1080/09546550109609669 PG 19 WC International Relations; Political Science SC International Relations; Government & Law GA V22TL UT WOS:000208297400003 ER PT J AU Hoffman, DK Zhang, H Shi, Z Kouri, DJ Lee, S Pollak, E AF Hoffman, DK Zhang, H Shi, Z Kouri, DJ Lee, S Pollak, E TI Dual propagation inversion of truncated signals SO THEORETICAL CHEMISTRY ACCOUNTS LA English DT Article DE dual propagation inversion; distributed approximating functional; Fourier transform; time correlation function; denoise ID FILTER-DIAGONALIZATION; TIME SIGNALS; SPECTROSCOPY; MODEL AB Fourier transforms occur in a variety of chemical systems and processes. A few examples include obtaining spectral information from correlation functions, energy relaxation processes, spectral densities obtained from force autocorrelation functions, etc. In this article, a new functional transform, named the dual propagation inversion (DPI) is introduced. The DPI Functional transform can be applied to a variety of problems in chemistry. such as Fourier transforms of time correlation functions. energy relaxation processes, rate theory. etc, The present illustrative application is to generating the frequency representation of a discrete, truncated time-domain signal. The DPI result is compared with the traditional Fourier transform applied to the same truncated time signal. For both noise-free and noise-corrupted time-truncated signals, the DPI spectrum is found to be more accurate. particularly as the signal is more severely truncated. In the DPI, the distributed-approximating-functional free propagator is used to propagate and denoise the signal simultaneously. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Univ Houston, Dept Chem, Houston, TX 77204 USA. Kyung Hee Univ, Dept Chem, Kyonggi Do 449701, South Korea. Weizmann Inst Sci, Dept Chem Phys, IL-76100 Rehovot, Israel. RP Hoffman, DK (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 26 TC 2 Z9 2 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1432-881X J9 THEOR CHEM ACC JI Theor. Chem. Acc. PD JAN PY 2001 VL 105 IS 3 BP 173 EP 181 DI 10.1007/s002140000197 PG 9 WC Chemistry, Physical SC Chemistry GA 398RX UT WOS:000166771100001 ER PT B AU Hale, DL Berry, RA AF Hale, DL Berry, RA BE Berndt, CC Khor, KA Lugscheider, EF TI Development of a coupled model to predict droplet deformation and solidification during splatting SO THERMAL SPRAY 2001: NEW SURFACES FOR A NEW MILLENNIUM LA English DT Proceedings Paper CT International Thermal Spray Conference (ITSC 2001) CY MAY 28-30, 2001 CL SINGAPORE, SINGAPORE SP ASM, Thermal Spray Soc, DVS, German Welding Soc, Int Inst Welding ID SURFACE AB Thermal spray is a melt-spray process in which material is melted and accelerated to high velocities, impinges upon a substrate, and rapidly solidifies to form a coating. Modeling the deposition dynamics of droplets is a key step towards understanding the evolution of a coating microstructure, since a coating is built up from the successive accumulation of many deformed, solidified droplets. This paper discusses some special effects testing of a particle model being developed by the authors to simulate the mechanics and thermodynamics associated with the simultaneous flattening and solidification of a fully liquid or partially solidified droplet. Rigorous validation of the numerical algorithm must necessarily be performed via this separate effects testing. C1 Idaho Natl Lab, Idaho Falls, ID USA. RP Hale, DL (reprint author), Idaho Natl Lab, Idaho Falls, ID USA. RI Guillen, Donna/B-9681-2017 OI Guillen, Donna/0000-0002-7718-4608 NR 23 TC 0 Z9 0 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA 9503 KINSMAN RD, MATERIALS PARK, OH 44073 USA BN 0-87170-737-3 PY 2001 BP 975 EP 984 PG 4 WC Materials Science, Characterization & Testing; Materials Science, Coatings & Films SC Materials Science GA BU67H UT WOS:000176681000133 ER PT S AU Sales, BC Chakoumakos, BC Keppens, V Jin, R Mandrus, D Thompson, JR AF Sales, BC Chakoumakos, BC Keppens, V Jin, R Mandrus, D Thompson, JR BE Nolas, GS Johnson, DC Mandrus, DG TI When does a crystal conduct heat like a glass? SO THERMOELECTRIC MATERIALS 2001-RESEARCH AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Thermoelectric Materials 2001 - Research and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc ID FILLED SKUTTERUDITE ANTIMONIDES; TRANSPORT-PROPERTIES; GE; EU8GA16GE30; SR; BA; SN AB Semiconducting crystalline materials that are poor conductors of heat are important as thermoelectric materials and for technological applications involving thermal management. In the present article neutron scattering, electrical and thermal transport, heat capacity, magnetic and acoustic measurements are reported on single crystals of three semiconductors with the type 1 clathrate structure: Ba8Ga16Ge30, Sr8Ga16Ge30 and Eu8Ga16Ge30. Taken together these measurements suggest specific structural features that result in a crystal with the lowest possible thermal conductivity, namely that of a glass with the same chemical composition. Weakly bound atoms that rattle within oversized atomic cages in a crystal result in a low thermal conductivity, but the present data show that both rattling atoms and tunneling states are necessary to produce a true glass-like thermal conductivity. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Sales, BC (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Mandrus, David/H-3090-2014; Chakoumakos, Bryan/A-5601-2016 OI Chakoumakos, Bryan/0000-0002-7870-6543 NR 21 TC 0 Z9 0 U1 1 U2 8 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-627-3 J9 MATER RES SOC SYMP P PY 2001 VL 691 BP 161 EP 168 PG 8 WC Materials Science, Multidisciplinary; Materials Science, Composites; Physics, Condensed Matter SC Materials Science; Physics GA BU84C UT WOS:000177163500019 ER PT S AU Zavadil, KR King, DB AF Zavadil, KR King, DB BE Nolas, GS Johnson, DC Mandrus, DG TI Thin film dispenser cathodes for thermionic micro-devices SO THERMOELECTRIC MATERIALS 2001-RESEARCH AND APPLICATIONS SE MATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT Symposium on Thermoelectric Materials 2001 - Research and Applications held at the 2001 MRS Fall Meeting CY NOV 26-29, 2001 CL BOSTON, MA SP Mat Res Soc ID EMISSION AB Electron emissive thin films that possess the thermionic properties of macroscale dispenser cathodes have been fabricated using standard RF sputter deposition techniques. These films are based on a compositionally modulated structure using W and a Ba-containing ternary oxide. These films exhibit uniform work function values of 1.9 to 2.2 eV with high emission coefficients of 2 to 26 A.cm(-2)K(-2). Electron microscopy shows that W layer coalescence and continued particle growth occurs with prolonged annealing, eventually disrupting the original surface layer. Chemical modification of the oxide during deposition may provide a route to limit the extent of W coalescence and preserve surface metallization layers on these films. These films are designed to be integrated into thermionic micro-devices. C1 Sandia Natl Labs, Mat & Proc Sci Ctr, Albuquerque, NM 87185 USA. RP Zavadil, KR (reprint author), Sandia Natl Labs, Mat & Proc Sci Ctr, POB 5800, Albuquerque, NM 87185 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DRIVE, WARRENDALE, PA 15088-7563 USA SN 0272-9172 BN 1-55899-627-3 J9 MATER RES SOC SYMP P PY 2001 VL 691 BP 385 EP 390 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Composites; Physics, Condensed Matter SC Materials Science; Physics GA BU84C UT WOS:000177163500052 ER PT S AU Wang, H Dinwiddie, RB AF Wang, H Dinwiddie, RB BE Rozlosnik, AE Dinwiddie, RB TI Synchronizing the IR camera to capture high-speed thermal transients SO THERMOSENSE XXIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Thermosense XXIII Conference CY APR 16-19, 2001 CL ORLANDO, FL SP SPIE DE infrared imaging; thermal transient; triggering and synchronization ID SIMULATION AB Thermal transients caused by electrical switching devices and fast optical or electrical pulses only exist for a very short time (less than 1 millisecond). If the transient happens in a high thermal conductivity material, e.g. silicon wafer, the thermal transient will disappear in a few milliseconds or faster. Most modern IR cameras have external triggering capability. However, the IR cameras often run on its own clock. If the triggering of data acquisition is not synchronized with the camera, there is often an uncertainty of timing, e.g. 16.7 ms for camera running at 60Hz. Even when the IR camera is running at 500 Hz, there is 2 ms uncertainty. Depending on when you push/click the button, the high-speed thermal transients can be missed and they will disappear in the next image. We developed a technique to synchronize the IR camera to capture the thermal transients. By using a delay function, we can control the data acquisition very precisely to study the thermal transients. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Wang, H (reprint author), Oak Ridge Natl Lab, Bldg 4515 MS-6064, Oak Ridge, TN 37831 USA. RI Wang, Hsin/A-1942-2013 OI Wang, Hsin/0000-0003-2426-9867 NR 5 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4055-8 J9 P SOC PHOTO-OPT INS PY 2001 VL 4360 BP 30 EP 36 DI 10.1117/12.421024 PG 7 WC Thermodynamics; Instruments & Instrumentation; Optics SC Thermodynamics; Instruments & Instrumentation; Optics GA BS34B UT WOS:000169530500004 ER PT S AU Villa-Aleman, E Garrett, AJ Kuzeja, RJ O'Steen, BL Pendergast, MM AF Villa-Aleman, E Garrett, AJ Kuzeja, RJ O'Steen, BL Pendergast, MM BE Rozlosnik, AE Dinwiddie, RB TI Thermal targets for satellite calibration SO THERMOSENSE XXIII SE Proceedings of SPIE LA English DT Proceedings Paper CT Thermosense XXIII Conference CY APR 16-19, 2001 CL ORLANDO, FL SP SPIE DE MTI satellite; ground truth; multispectral imaging AB The Savannah River Technology Center (SRTC) is currently calibrating the Multispectral Thermal Imager (MTI) satellite sponsored by the Department of Energy. The MTI imager is a research and development project with 15 wavebands in the visible, near-infrared, short-wave infrared, mid-wave infrared and long-wave infrared spectral regions. A plethora of targets with known temperatures such as power plant heated lakes, volcano lava vents, desert playas and aluminized Mylar tarps are being used in the validation of the five thermal bands of the MTI satellite. SRTC efforts in the production of "cold targets" with aluminized Mylar tarps will be described. Visible and thermal imagery and wavelength dependent radiance measurements of the calibration targets will be presented. C1 Savannah River Technol Ctr, Aiken, SC 29808 USA. RP Savannah River Technol Ctr, Aiken, SC 29808 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4055-8 J9 PROC SPIE PY 2001 VL 4360 BP 427 EP 437 DI 10.1117/12.421021 PG 11 WC Thermodynamics; Instruments & Instrumentation; Optics SC Thermodynamics; Instruments & Instrumentation; Optics GA BS34B UT WOS:000169530500049 ER PT S AU Miller, WO AF Miller, WO BE Rozlosnik, AE Dinwiddie, RB TI An evaluation of Sonic IR for NDE at Lawrence Livermore National Laboratory SO THERMOSENSE XXIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Thermosense XXIII Conference CY APR 16-19, 2001 CL ORLANDO, FL SP SPIE DE Sonic IR; infrared thermography; nondestructive evaluation; dynamics; modal analysis AB Sonic IR was evaluated as an NDE technique at LLNL using a commercial ThermoSoniX system from Indigo Systems Corp. The main effort was to detect small cracks in aluminum oxide, a dense stiff ceramic. Test coupons were made containing 0.2-mm cracks by surface grinding, l-mm cracks by compression with a Vickers bit, and 4-mm cracks by 3-point bending. Only the 3-point bend cracks produced thermal images. Several parts shattered during testing, perhaps by being forced at resonance by the 20-kHz acoustic probe. Tests on damaged carbon composite coupons produced thermal images that were in excellent agreement with ultrasonic inspection. The composite results also showed some dependence on contact location of the acoustic probe, and on the method of support. Tests on glass with surface damage produced weak images at the pits. Tests on metal ballistic targets produced thermal images at the impact sites. Modal analyses suggest that the input frequency should be matched to the desired response, and also that forced resonance damaged some parts. C1 Univ Calif Lawrence Livermore Natl Lab, New Technol Engn Div, Thermal Fluids Grp, Livermore, CA 94551 USA. RP Miller, WO (reprint author), Univ Calif Lawrence Livermore Natl Lab, New Technol Engn Div, Thermal Fluids Grp, POB 808,L-140, Livermore, CA 94551 USA. NR 8 TC 8 Z9 8 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4055-8 J9 P SOC PHOTO-OPT INS PY 2001 VL 4360 BP 534 EP 545 DI 10.1117/12.420978 PG 12 WC Thermodynamics; Instruments & Instrumentation; Optics SC Thermodynamics; Instruments & Instrumentation; Optics GA BS34B UT WOS:000169530500061 ER PT B AU Porter, R Gokhale, M Harvey, N Perkins, S Young, C AF Porter, R Gokhale, M Harvey, N Perkins, S Young, C BE Keymeulen, D Stoica, A Lohn, J Zebulum, RS TI Evolving network architectures with custom computers for multi-spectral feature identification SO THIRD NASA/DOD WORKSHOP ON EVOLVABLE HARDWARE, PROCEEDINGS LA English DT Proceedings Paper CT 3rd NASA/DoD Workshop on Evolvable Hardware (EH-2001) CY JUL 12-14, 2001 CL LONG BEACH, CA SP NASA, US Dept Def, Def Adv Res Projects Agcy, Caltech, Jet Prop Lab AB This paper investigates the design of evolvable FPGA circuits where the design space is severely constrained to an interconnected network of meaningful high-level operators. The specific design domain is image processing, especially pattern recognition in remotely sensed images. Preliminary experiments are reported that compare Neural Networks with a recently introduced variant known as Morphological Networks. A novel network node is then presented that is particularly suited to the problem of pattern recognition in multi-spectral data sets. More specifically, the node can exploit both spectral and spatial information, and implements both feature extraction and classification components of a typical image processing pipeline. Once trained, the network can be applied to large image data sets, or at the sensor to extract features of interest with two orders of magnitude speed-up compared to software implementations. C1 Los Alamos Natl Lab, NIS2, Los Alamos, NM 87544 USA. RP Porter, R (reprint author), Los Alamos Natl Lab, NIS2, POB 1663, Los Alamos, NM 87544 USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1180-5 PY 2001 BP 261 EP 270 DI 10.1109/EH.2001.937970 PG 10 WC Engineering, Aerospace; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Robotics SC Engineering; Computer Science; Robotics GA BS63J UT WOS:000170639500030 ER PT B AU Otoo, EJ Shoshani, A Hwang, S AF Otoo, EJ Shoshani, A Hwang, S BE Kerschberg, L Kafatos, M TI Clustering high dimensional massive scientific datasets SO THIRTEENTH INTERNATIONAL CONFERENCE ON SCIENTIFIC AND STATISTICAL DATABASE MANAGEMENT, PROCEEDINGS LA English DT Proceedings Paper CT 13th International Conference on Scientific and Statistical Database Management (SSDBM 2001) CY JUL 18-20, 2001 CL FAIRFAX, VA SP Ctr Earth Observing & Space Res, Ctr Informat Syst Integrat & Evolut, E Ctr for E Business, George Mason Univ, ACM SIGMOD, IEEE TC Data Engn, VLDB Endowment AB Many scientific applications can benefit from efficient clustering algorithm of massively large high dimensional datasets. However most of the developed algorithms are impractical to use when the amount of data is very large. Given N objects each defined by an M-dimensional feature vector, any clustering technique for handling very large datasets in high dimensional space should run in time O(N) at best, and O(N log N) in the worst case, using no more than O(NM) storage, for it to be practical. A parallelized version of the same algorithm should achieve a linear speed-up in processing time with increasing number of processors. We introduce a hybrid algorithm called HyCeltyc, as an approach for clustering massively large high dimensional datasets. HyCeltyc, which stands for Hybrid Cell Density Clustering method, combines a cell-density based algorithm with a hierarchical agglomerative method to identify clusters in linear time. The main steps of the algorithm involve sampling, dimensionality reduction and selection of significant features on which to cluster the data. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Natl Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 23 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-1218-6 PY 2001 BP 147 EP 157 PG 5 WC Computer Science, Information Systems SC Computer Science GA BS91R UT WOS:000171370000013 ER PT S AU Demos, SG Staggs, M Radousky, HB AF Demos, SG Staggs, M Radousky, HB BE Conchello, JA Cogswell, CJ Wilson, T TI Endoscopic subsurface imaging in tissues SO THREE-DIMENSIONAL AND MULTIDIMENSIONAL MICROSCOPY: IMAGE ACQUISITION AND PROCESSING VIII SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on 3-Dimensional and Multidimensional Microscopy - Image Acquisition and Processing VIII CY JAN 21-22, 2001 CL SAN JOSE, CA SP SPIE DE polarization; tissues; backscattering; subsurface imaging ID POLARIZATION AB The objective of this work is to develop endoscopic subsurface optical imaging technology that will be able to image different tissue components located underneath the surface of the tissue at an imaging depth of up to I centimeter. This effort is based on the utilization of existing technology and components developed for medical endoscopes with the incorporation of the appropriate modifications to implement the spectral and polarization difference imaging technique. This subsurface imaging technique employs polarization and spectral light discrimination in combination with image processing to remove a large portion of the image information from the outer layers of the tissue which leads to enhancement of the contrast and image qualify of subsurface tissue structures. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Univ Calif Lawrence Livermore Natl Lab, POB 808,L-411, Livermore, CA 94551 USA. EM Demos.1@llnl.gov NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3939-8 J9 PROC SPIE PY 2001 VL 4261 BP 122 EP 125 DI 10.1117/12.424526 PG 4 WC Microscopy; Radiology, Nuclear Medicine & Medical Imaging SC Microscopy; Radiology, Nuclear Medicine & Medical Imaging GA BS45X UT WOS:000169896200014 ER PT B AU Blackman, HS Hallbert, BP Byers, JC Hill, SG Reece, WJ AF Blackman, HS Hallbert, BP Byers, JC Hill, SG Reece, WJ BE Vanderdonckt, J Farenc, C TI Approaches to the evolving human-computer interface: application to computerized procedures in high-risk industries SO TOOLS FOR WORKING WITH GUIDELINES LA English DT Proceedings Paper CT Annual Meeting of the Special Interest Group on Tools for Working with Guidelines (TFWWG 2000) CY OCT, 2000 CL BIARRITZ, FRANCE AB The purpose of this paper is twofold. First to provide a description of the direction that research in human-computer interface must evolve, and second to describe one research effort directed at filling a specific gap in the literature. Due to the rapid growth in technology (particularly computers) the human-system interface is rapidly changing thereby introducing new challenges. The prevailing paradigm in human-machine interaction has emphasized human-system interactions that are based on a machine-oriented dialogue. We propose an approach of basing the design of human-machine systems on psychological and biological-centered principles, rather than the hottest new technology of the day. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Blackman, HS (reprint author), Idaho Natl Engn & Environm Lab, POB 1625,2525 Freemont Ave, Idaho Falls, ID 83415 USA. RI Hallbert, Bruce/B-5435-2017 OI Hallbert, Bruce/0000-0002-4133-7625 NR 12 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG LONDON LTD PI GODALMING PA SWEETAPPLE HOUSE CATTESHALL RD FARNCOMBE, GODALMING GU7 1NH, SURREY, ENGLAND BN 1-85233-355-3 PY 2001 BP 117 EP 125 PG 9 WC Computer Science, Cybernetics; Computer Science, Software Engineering SC Computer Science GA BR22V UT WOS:000165906000011 ER PT J AU Bennett, LM McAllister, KA Ward, T Malphurs, J Collins, NK Seely, JC Davis, BJ Wiseman, RW AF Bennett, LM McAllister, KA Ward, T Malphurs, J Collins, NK Seely, JC Davis, BJ Wiseman, RW TI Mammary tumor induction and premature ovarian failure in Apc(Min) mice are not enhanced by Brca2 deficiency SO TOXICOLOGIC PATHOLOGY LA English DT Article DE mammary ducts; morphology; breast cancer; adenoacanthoma; hormone; Wnt pathway ID BREAST-CANCER SUSCEPTIBILITY; BETA-CATENIN; APC GENE; COLORECTAL-CANCER; MOUSE MODEL; E-CADHERIN; MUTATIONS; SKIN; EXPRESSION; ACTIVATION AB Inherited BRCA2 mutations predispose individuals to breast cancer and increase risk at other sites. Recent studies have suggested a role for the APC I1307K allele as a low-penetrance breast cancer susceptibility gene that enhances the phenotypic effects of BRCA1 and BRCA2 mutations. To model the consequences of inheriting mutant alleles of the BRCA2 and APC tumor suppressor genes, we examined tumor outcome in C57BL/6 mice with mutations in the Brca2 and Ape genes. We hypothesized that if the Brca2 and Ape genes were interacting to influence mammary tumor susceptibility. then mammary tumor incidence and/or multiplicity would be altered in mice that had inherited mutations in both genes. Female and male offspring treated with a single IP injection of 50 mg/kg N-ethyl-N-nitrosourea (ENU) at 35 days of age developed mammary adenoacanthomas by 100 days of age. The female Ape-mutant and Brca2/Apc double-mutant progeny had mean mammary tumor multiplicities of 6.7 +/- 2.8 and 7.2 +/- 2.7, respectively. compared to wild-type and Brca2-mutant females, which had mean mammary tumor multiplicities of 0.1 +/- 0.4 and 0.3 +/- 0.5. respectively. Female ENU-treated Ape-mutant and Brca2/Apc double heterozygotes were also susceptible to premature ovarian failure. Thus, the inheritance of an Ape mutation predisposes ENU-treated female and male mice to mammary tumors and, in the case of female mice, to ovarian failure. These results indicate that mammary tumor development in Ape-mutant mice can progress independently of ovarian hormones. The Ape mutation-driven phenotypes were not modified by mutation of Brca2, perhaps because Brca2 acts in a hormonally dependent pathway of mammary carcinogenesis. C1 NIEHS, Mol Carcinogenesis Lab, NIH, Res Triangle Pk, NC 27709 USA. RP Bennett, LM (reprint author), Univ Calif Lawrence Livermore Natl Lab, BBRP-L-448,BT 3703-R1249,POB 808,7000 East Ave, Livermore, CA 94551 USA. NR 46 TC 7 Z9 7 U1 0 U2 1 PU SOC TOXICOLOGIC PATHOLOGISTS PI MT ROYAL PA 19 MANTUA RD, MT ROYAL, NJ 08061 USA SN 0192-6233 J9 TOXICOL PATHOL JI Toxicol. Pathol. PD JAN-FEB PY 2001 VL 29 IS 1 BP 117 EP 125 PG 9 WC Pathology; Toxicology SC Pathology; Toxicology GA 400WE UT WOS:000166894000014 PM 11215675 ER PT J AU Lingohr, MK Thrall, BD Bull, RJ AF Lingohr, MK Thrall, BD Bull, RJ TI Effects of dichloroacetate (DCA) on serum insulin levels and insulin-controlled signaling proteins in livers of male B6C3F1 mice SO TOXICOLOGICAL SCIENCES LA English DT Article DE dichloroacetate; glycogen; insulin; signaling; insulin receptor PKB; hepatocarcinogen ID HEPATOMA-CELL LINE; GROWTH-FACTOR; TRICHLOROACETIC-ACID; MURINE HEPATOCYTES; DRINKING-WATER; RECEPTOR; RAT; MUTAGENICITY; MOUSE; HEPATOCARCINOGENESIS AB DCA is hepatocarcinogenic in rodents. At carcinogenic doses, DCA causes a large accumulation of liver glycogen, Thus, we studied the effects of DCA treatment on insulin levels and expression of insulin-controlled signaling proteins in the liver. DCA treatment (0.2-2.0 g/l in drinking water for 2 weeks) reduced serum insulin levels. The decrease persisted for at least 8 weeks. In livers of mice treated with DCA for 2-, 10-, and 52-week periods, insulin receptor (IR) protein levels were significantly depressed. Additionally, protein kinase B (PKB alpha) expression decreased significantly with DCA treatment. In normal liver, glycogen levels were increased as early as at 1 week, and this effect preceded changes in insulin and IR and PKB alpha. In contrast to normal liver, IR protein was elevated in DCA-induced liver tumors relative to that in liver tissue of untreated animals and to an even greater extent when compared to adjacent normal liver in the treated animal. Mitogen-activated protein kinase (MAP kinase) phosphorylation was also increased in tumor tissue relative to normal liver tissue and tissue from untreated controls. These data suggest that normal hepatocytes down-regulate insulin-signaling proteins in response to the accumulation of liver glycogen caused by DCA. Futhermore, these results suggest that the initiated cell population, which does not accumulate glycogen and is promoted by DCA treatment, responds differently from normal hepatocytes to the insulin-like effects of this chemical. The differential sensitivity of the 2 cell populations may contribute to the tumorigenic effects of DCA in the liver. C1 Washington State Univ, Pullman, WA 99164 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Bull, RJ (reprint author), MoBull Consulting, 8382 Gage Blvd,Suite O,Box 511, Kennewick, WA 99336 USA. NR 44 TC 15 Z9 15 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1096-6080 J9 TOXICOL SCI JI Toxicol. Sci. PD JAN PY 2001 VL 59 IS 1 BP 178 EP 184 DI 10.1093/toxsci/59.1.178 PG 7 WC Toxicology SC Toxicology GA 392CF UT WOS:000166392500019 PM 11134557 ER PT J AU Wiley, HS Burke, PM AF Wiley, HS Burke, PM TI Regulation of receptor tyrosine kinase signaling by endocytic trafficking SO TRAFFIC LA English DT Review DE EGFR; endosome; insulin receptor; TrkA; tyrosine kinase; ubiquitin ID EPIDERMAL GROWTH-FACTOR; CLATHRIN-MEDIATED ENDOCYTOSIS; INSULIN-RECEPTOR; EGF RECEPTOR; POSTENDOCYTIC TRAFFICKING; RETROGRADE TRANSPORT; DOWN-REGULATION; ERBB RECEPTORS; INTERNALIZATION; ACTIVATION AB Activated receptor tyrosine kinase (RTK) receptors are rapidly internalized and eventually delivered to the lysosomes. Although ligand-induced endocytosis was originally thought to be a mechanism of receptor inactivation, many studies suggest that receptors remain active within endosomes. This review discusses the role that internalized signaling complexes may play in different RTK systems including recent data on how ubiquitination may regulate this process. In general, it appears that some receptor systems have evolved to enhance endosomal signaling, as is the case for TrkA and NGF. In contrast, the insulin receptor system appears to limit the extent of endosomal signaling. The EGFR system is the intermediate example. In this case, some signals are specifically generated from the cell surface while others appear to be generated from within endosomes. This may act as a mechanism to produce ligand-specific signals. Thus, trafficking could play diverse roles in receptor signaling, depending on the specific cell and tissue type. C1 Pacific NW Natl Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. Univ Utah, Dept Pathol, Salt Lake City, UT 84132 USA. RP Wiley, HS (reprint author), Pacific NW Natl Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. FU NICHD NIH HHS [P01-HD28528] NR 62 TC 169 Z9 171 U1 1 U2 12 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 1398-9219 J9 TRAFFIC JI Traffic PD JAN PY 2001 VL 2 IS 1 BP 12 EP 18 DI 10.1034/j.1600-0854.2001.020103.x PG 7 WC Cell Biology SC Cell Biology GA 398ZK UT WOS:000166786200002 PM 11208164 ER PT B AU Alman, DE Wilson, RD Paul, BK AF Alman, DE Wilson, RD Paul, BK GP NAMRI/SME NAMRI/SME TI Fabrication of NiAl intermetallic reactors for Microtechnology-based Energy Chemical Systems (MECS) SO TRANSACTIONS OF THE NORTH AMERICAN MANUFACTURING RESEARCH INSTITUTION OF SME, VOL XXIX, 2001 LA English DT Proceedings Paper CT 29th North American Manufacturing Research Conference (NAMRC XXIX) CY MAY 22-25, 2001 CL GAINESVILLE, FL SP Soc Mfg Engineers, N Amer Mfg Res Inst ID COMPOSITES; FOILS; AL AB Microtechnology-based Energy Chemical Systems (MECS) offer opportunities for portable power generation, on-site waste remediation, point-of-use chemical synthesis, and heat-transfer. The material requirements for this application include chemical inertness and the ability to be fabricated into structures that contain internal features of complex geometries and small (<250 mum) dimensions. It has been recognized that materials with limited formability, like ceramics and intermetallics, maybe required for high temperature applications. In this paper, a method for forming an array of internal microchannels in a NiAl device is presented. Microchannels are precision machined (via laser ablation) into elemental Ni and Al foils. During bonding, theses foils are converted into NiAl. Result show that this is a viable method for producing aluminide-based structures containing complex, internal features. C1 US DOE, Off Fossil Energy, Albany Res Ctr, Albany, OR 97321 USA. RP Alman, DE (reprint author), US DOE, Off Fossil Energy, Albany Res Ctr, Albany, OR 97321 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU SOC MANUFACTURING ENGINEERS PI DEARBORN PA ONE SME DR, PO BOX 930, DEARBORN, MI 48128 USA BN 0-87263-600-3 PY 2001 BP 453 EP 459 PG 7 WC Engineering, Manufacturing; Engineering, Mechanical; Metallurgy & Metallurgical Engineering SC Engineering; Metallurgy & Metallurgical Engineering GA BV60L UT WOS:000179483900060 ER PT B AU Galambos, P Zavadil, K Givler, R Peter, F Gooray, A Roller, G Crowley, J AF Galambos, P Zavadil, K Givler, R Peter, F Gooray, A Roller, G Crowley, J BE Obermeier, E TI A surface micromachined electrostatic drop ejector SO TRANSDUCERS '01: EUROSENSORS XV, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 11th International Conference on Solid-State Sensors and Actuators CY JUN 10-14, 2001 CL MUNICH, GERMANY SP AESCULAP AG & Co KG, Robert Bosch GmbH, DiamlerChrysler AG, Deutsch Forsch Gemeinsch, EADS Deutschland GmbH, Elsevier Sci, EUROPRACTICE, Fraunhofer IMS Munchen, 1st Sensor Technol, GEFRAN SPA, HL Planartech GmbH, Infineon Technol AG, Inst Phys Publ, KELLER AG, Kistler Instrumente AG, MEMS Ind Grp, Regier von Oberbayern, SCHMIDT Feintechn GmbH, Springer Verlag Heidelberg, TEMIC, TU Berlin MAT, IEEE Electron Devices Soc DE ejector; electrostatic; surface-micromachining AB Ejectors have applications ranging from ink jet printing to drug delivery. A novel electrostatic ejector was surface micromachined; and satellite-free, 2 pl drops were ejected at 10 m/s using an electrostatic field (E-field) of 20 V/mum. The Meld is applied across the ejected liquid, which simplifies device design, but allows the possibility of dielectric breakdown and electrolysis in the liquid. These challenges were overcome in the prototype described herein. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Galambos, P (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 10 TC 2 Z9 2 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42150-5 PY 2001 BP 906 EP 909 PG 4 WC Engineering, Biomedical; Engineering, Electrical & Electronic; Optics; Polymer Science SC Engineering; Optics; Polymer Science GA BT29W UT WOS:000172547800208 ER PT B AU Fleming, JG Lin, SY AF Fleming, JG Lin, SY BE Obermeier, E TI Waveguiding in MEMS compatible 3-D, silicon photonic lattices SO TRANSDUCERS '01: EUROSENSORS XV, DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2 LA English DT Proceedings Paper CT 11th International Conference on Solid-State Sensors and Actuators CY JUN 10-14, 2001 CL MUNICH, GERMANY SP AESCULAP AG & Co KG, Robert Bosch GmbH, DiamlerChrysler AG, Deutsch Forsch Gemeinsch, EADS Deutschland GmbH, Elsevier Sci, EUROPRACTICE, Fraunhofer IMS Munchen, 1st Sensor Technol, GEFRAN SPA, HL Planartech GmbH, Infineon Technol AG, Inst Phys Publ, KELLER AG, Kistler Instrumente AG, MEMS Ind Grp, Regier von Oberbayern, SCHMIDT Feintechn GmbH, Springer Verlag Heidelberg, TEMIC, TU Berlin MAT, IEEE Electron Devices Soc DE photonic lattice; waveguides ID CRYSTALS; BAND AB Photonic Lattices can be thought of as the photonic analogue of semiconductors in that there exists a band of photon energies forbidden to exist within the structure. 3-D lattices are complex, however, we have been able to fabricate them using,processes compatible with both CMOS and MEMS. Since light is confined in all three dimensions in these structures it has been theoretically predicted that light can be guided through such structures with high efficiency. Waveguiding in these structures has now also been experimentally demonstrated. There are also many other potential applications of these structures. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Fleming, JG (reprint author), Sandia Natl Labs, MS 1080,POB 5800, Albuquerque, NM 87185 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY BN 3-540-42150-5 PY 2001 BP 1344 EP 1347 PG 4 WC Engineering, Biomedical; Engineering, Electrical & Electronic; Optics; Polymer Science SC Engineering; Optics; Polymer Science GA BT29W UT WOS:000172547800310 ER PT S AU Chin, SM Hwang, HL Greene, DL AF Chin, SM Hwang, HL Greene, DL GP NRC TI In, out, within, and through - Geography of truck freight in the lower 48 SO TRANSPORTATION DATA AND INFORMATION TECHNOLOGY: PLANNING AND ADMINISTRATION SE TRANSPORTATION RESEARCH RECORD LA English DT Article; Proceedings Paper CT 80th Annual Meeting of the Transportation-Research-Board CY JAN, 2001 CL WASHINGTON, D.C. SP Transportat Res Board AB The 1993 Commodity Flow Survey (CFS) proved that most freight transport on U.S. highways is interstate. The nation's highway system functions principally to link the economies of states to form an integrated national economy rather than to serve the economies of individual states. Data from the 1997 CFS allow comparisons with the 1993 data to determine (a) whether the predominant pattern of interstate shipments continues as a stable phenomenon; (b) how fast the within-, from-, to-, and through-state components of truck freight are growing; and (c) whether important regional trends are evident. The shipment of freight by truck in the United States was even more predominantly interstate in 1997 than in 1993. In 1997, interstate shipments made up 76 percent of the total tonmiles shipped by truck; in 1993 it was 73 percent. The proportions of truck freight shipments originating from, destined to, passing through, or occurring entirely within a state vary significantly from state to state. Individual state distributions remained relatively stable from 1993 to 1997, with the exceptions of dramatic increases in interstate truck ton-miles in small New England states and substantial but less-dramatic increases in border states, such as New York, Michigan, Washington, California, Texas, and Florida. These findings could have important implications for highway revenue allocations because trucks carrying freight play a significant role in damage to highway pavements and structures. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Chin, SM (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 22 TC 0 Z9 0 U1 1 U2 1 PU TRANSPORTATION RESEARCH BOARD NATL RESEARCH COUNCIL PI WASHINGTON PA 500 FIFTH ST, NW, WASHINGTON, DC 20001 USA SN 0361-1981 BN 0-309-07230-1 J9 TRANSPORT RES REC PY 2001 IS 1768 BP 18 EP 25 PG 8 WC Engineering, Civil; Transportation Science & Technology SC Engineering; Transportation GA BU64V UT WOS:000176595000003 ER PT J AU Zhang, XH Gates, RS Anders, S Hsu, SM AF Zhang, XH Gates, RS Anders, S Hsu, SM TI An accelerated wear test method to evaluate lubricant thin films on magnetic hard disks SO TRIBOLOGY LETTERS LA English DT Article DE magnetic hard disks; lubrication; lubricant; monolayer; Z-Dol; durability ID RECORDING DISKS AB A high speed ball-on-inclined-plane test method has been developed to evaluate the lubrication effectiveness of Z-Dol on magnetic hard disks. The test evaluates the combined durability of the lubricant film and the carbon overcoat under sliding conditions. A polished ruby (Al2O3) ball without suspension is used to simulate the head material. The ball slides over an inclined (at an angle of 0.055 degrees +/- 0.005 degrees) section of the disk surface at 2.0 m/s linear velocity, The load is controlled by the geometric interference of the preloaded ball and the inclined plane. The contact forces are sampled periodically at 2 rpm and the frictional coefficients calculated. Repeated sliding between the ball and the disk sample leads to an increase in friction approaching that of the unlubricated case, Post test analysis using atomic force microscopy (AFM) suggests that the increase in friction is due to the loss of lubricant effectiveness of the lubricant and the wear of the carbon overcoat. X-ray photoemission microscopy (PEEM) results suggest progressive oxidation of Z-Dol as one of the degradation mechanisms leading to wear. The durability of the lubricating thin films is defined by the number of cycles to failure. Test repeatability is about 10%, depending on lubricant, film thickness, and surface roughness. The test cart be used to evaluate different lubricant chemistries as well as different carbon overcoats. Compared to other pin-on-disk tests and step loading ball-on-disk methods, this test introduces two additional factors: high speed impact and wear acceleration by the inclined angle. The high speed impact simulates potential thermal stresses associated with head-disk contact. With an inclined angle, the load increases evenly for each contact cycle, hence simulates the ability of the lubricant layer to react to dynamic loads. The test is intended as a basic research tool to measure the fundamental resistance of the lubricant layer to resist repeated high speed contacts. C1 Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Zhang, XH (reprint author), Univ Maryland, College Pk, MD 20742 USA. RI Raoux, Simone/G-3920-2016 NR 11 TC 17 Z9 18 U1 0 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PY 2001 VL 11 IS 1 BP 15 EP 21 DI 10.1023/A:1016677321278 PG 7 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 466VV UT WOS:000170667600003 ER PT J AU Salmeron, M AF Salmeron, M TI Generation of defects in model lubricant monolayers and their contribution to energy dissipation in friction SO TRIBOLOGY LETTERS LA English DT Article DE friction; self-assembled monolayers; energy dissipation mechanisms ID ATOMIC-FORCE MICROSCOPY; SELF-ASSEMBLED MONOLAYERS; CHAIN-LENGTH DEPENDENCE; MOLECULAR-STRUCTURE; FILMS; PRESSURE; AU(111); ALKANETHIOLS; SURFACE; DIAMOND AB The structural, mechanical (friction) and spectroscopic properties of model lubricant films made of self-assembled and Langmuir-Blodgett monolayers on quartz, mica and gold have been investigated with atomic force microscopy, the surface forces apparatus and sum-frequency generation. In these films, the molecules tend to form densely packed structures, with the alkane chains mostly vertical and parallel to each other. The SFG results suggest that under moderate pressures of a few tens of MPa, the methyl end group of the alkane chains is rotated to accommodate a terminal gauche distortion. The molecule, however, retains its upright close-packed structure with a lattice periodicity when ordered, which can be resolved by AFM. At pressures above 0.1 GPa, changes in the form of collective molecular tilts take place that lower the height of the monolayer. Only certain angles of tilt are allowed that are explained by the interlocking of methylene units in neighboring chains. The discrete angular tilts are accompanied by increases in friction. A model based on the van der Waals attractive energy between chains is used to explain the stability of the films and to estimate the cohesive energy changes during tilt and, from that, the increases in friction force. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. NR 30 TC 89 Z9 89 U1 1 U2 24 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD JAN-MAR PY 2001 VL 10 IS 1-2 BP 69 EP 79 DI 10.1023/A:1009026312732 PG 11 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 434ZT UT WOS:000168846300010 ER PT J AU Burns, AR Carpick, RW Sasaki, DY Shelnutt, JA Haddad, R AF Burns, AR Carpick, RW Sasaki, DY Shelnutt, JA Haddad, R TI Shear-induced mechanochromism in polydiacetylene monolayers SO TRIBOLOGY LETTERS LA English DT Article DE atomic force microscopy; friction force microscopy; friction anisotropy; shear force microscopy; nanotribology; polydiacetylenes; LB films; molecular mechanics; conjugated polymers ID SINGLE MOLECULAR LAYERS; ELECTRONIC-STRUCTURE; CONJUGATED POLYMERS; CONFORMATIONAL DISORDER; FLUORESCENCE; DIACETYLENE; FILMS; COLOR AB We use atomic force microscopy to actuate and characterize the nanoscale "mechanochromism" of polydiacetylene monolayers on atomically-flat silicon oxide substrates. We find explicit evidence that the irreversible blue-to-red transformation is caused by shear forces exerted normal to the polydiacetylene polymer backbone. The anisotropic probe-induced transformation is characterized by a significant change in the tilt orientation of the side chains with respect to the surface normal. We discuss preliminary molecular dynamics simulations and electronic structure calculations on twelve-unit polydiacetylene oligomers that allow us to correlate the transformation with bond-angle changes in the conjugated polymer backbone. C1 Sandia Natl Labs, MS 1413, Albuquerque, NM 87185 USA. Univ New Mexico, Dept Chem Engn, Albuquerque, NM 87131 USA. RP Burns, AR (reprint author), Sandia Natl Labs, MS 1413, POB 5800, Albuquerque, NM 87185 USA. RI Shelnutt, John/A-9987-2009 OI Shelnutt, John/0000-0001-7368-582X NR 24 TC 23 Z9 23 U1 6 U2 26 PU BALTZER SCI PUBL BV PI BUSSUM PA PO BOX 221, 1400 AE BUSSUM, NETHERLANDS SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD JAN-MAR PY 2001 VL 10 IS 1-2 BP 89 EP 96 DI 10.1023/A:1009018110915 PG 8 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 434ZT UT WOS:000168846300012 ER PT J AU Kim, HI Boiadjiev, V Houston, JE Zhu, XY Kiely, JD AF Kim, HI Boiadjiev, V Houston, JE Zhu, XY Kiely, JD TI Tribological properties of self-assembled monolayers on Au, SiOx and Si surfaces SO TRIBOLOGY LETTERS LA English DT Article DE IFM; self-assembled monolayers; tribology; silicon substrate ID ATOMIC-FORCE MICROSCOPY; SCANNING-TUNNELING-MICROSCOPY; CHAIN-LENGTH DEPENDENCE; ALKANETHIOLATE MONOLAYERS; FRICTIONAL-PROPERTIES; GOLD SURFACES; SILICON; MOLECULES; AU(111); FILMS AB Using interfacial force microscopy (IFM), the tribological properties of self-assembled monolayers (SAM) on Si surfaces produced by a new chemical strategy are investigated and compared to those of "classical" SAM systems, which include alkanethiols on Au and alkylsilanes on SiOx. The new SAM films are prepared by depositing n-alkyl chains with OH-terminations onto Cl-terninated Si substrates. The chemical nature of the actual lubricating molecules, n-dodecyl, is kept constant in all three thin film systems for direct comparison and similarities and differences in tribological properties are observed. The adhesion strength is virtually identical for all three systems; however, frictional properties differ due to differences in film packing. Differences in the chemical bonds that attach the lubricant molecules to the substrate are also discussed as they influence variations in film wear and durability. It is demonstrated that the new SAM films are capable of controlling the friction and adhesion of Si surfaces equally well as the classical SAMs and are potentially more reproducible and more durable. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Seagate Res, Pittsburgh, PA 15203 USA. RP Kim, HI (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 33 TC 29 Z9 32 U1 1 U2 6 PU BALTZER SCI PUBL BV PI BUSSUM PA PO BOX 221, 1400 AE BUSSUM, NETHERLANDS SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD JAN-MAR PY 2001 VL 10 IS 1-2 BP 97 EP 101 DI 10.1023/A:1009014010006 PG 5 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 434ZT UT WOS:000168846300013 ER PT J AU Kushmerick, JG Hankins, MG de Boer, MP Clews, PJ Carpick, RW Bunker, BC AF Kushmerick, JG Hankins, MG de Boer, MP Clews, PJ Carpick, RW Bunker, BC TI The influence of coating structure on micromachine stiction SO TRIBOLOGY LETTERS LA English DT Article DE thin films; MEMS; adhesion; self-assembled monolayers; FDTS ID SELF-ASSEMBLED MONOLAYERS; SURFACE; DEPOSITION; ADHESION; BEAMS; MEMS AB Stiction and friction in micromachines ir: commonly inhibited through the use of silane coupling agents such as 1H-, 1H-, 2H-, 2H-perfluorodecyltrichlorosilane (FDTS). FDTS coatings have allowed micromachine parts processed in water to be released without debilitating capillary adhesion occurring. These coatings are frequently considered as densely-packed monolayers, well-bonded to the substrate. In this paper, it is demonstrated that FDTS coatings can exhibit complex nanoscale structures, which control whether micromachine parts release or not. Surface images obtained via atomic force microscopy reveal that FDTS coating solutions can generate micellar aggregates that deposit on substrate surfaces. Interferometric imaging of model beam structures shows that stiction is high when the droplets are present and low when only monolayers are deposited. As the aggregate thickness (tens of nanometers) is insufficient to bridge the 2 mum gap under the beams, the aggregates appear to promote beam-substrate adhesion by changing the wetting characteristics of coated surfaces. Contact angle measurements and condensation figure experiments have been performed on surfaces and under coated beams to quantify the changes in interfacial properties that accompany different coating structures. These results may explain the irreproducibility that is often observed with these films. C1 Sandia Natl Labs, MS 1413, Albuquerque, NM 87185 USA. Sandia Natl Labs, MS 1084, MDL Operat 1746, Albuquerque, NM 87185 USA. Sandia Natl Labs, MS 1080, Albuquerque, NM 87185 USA. RP Kushmerick, JG (reprint author), Sandia Natl Labs, MS 1413, POB 5800, Albuquerque, NM 87185 USA. RI Kushmerick, James/C-2882-2008; de Boer, Maarten/C-1525-2013 OI de Boer, Maarten/0000-0003-1574-9324 NR 17 TC 26 Z9 27 U1 0 U2 17 PU BALTZER SCI PUBL BV PI BUSSUM PA PO BOX 221, 1400 AE BUSSUM, NETHERLANDS SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD JAN-MAR PY 2001 VL 10 IS 1-2 BP 103 EP 108 DI 10.1023/A:1009082530479 PG 6 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 434ZT UT WOS:000168846300014 ER PT S AU Wang, J Balaz, M Pianetta, P Baur, K Brennan, S AF Wang, J Balaz, M Pianetta, P Baur, K Brennan, S BE Heyns, M Mertens, P Meuris, M TI Investigation of trace metals analyses of dry residue on silicon wafer surfaces by TXRF and ICP-MS SO ULTRA CLEAN PROCESSING OF SILICON SURFACES 2000 SE SOLID STATE PHENOMENA LA English DT Article; Proceedings Paper CT 5th International Symposium on Ultra Clean Processing of Silicon Surfaces (UCPSS 2000) CY SEP 18-20, 2000 CL OOSTENDE, BELGIUM SP Akrion, Arch Chem, Ashland Chem, ATMI, EKC Technol Ltd, GeMeTeC, Horiba Europe, IMEC, IN USA Inc, Infineon Technol, KLA Tencor, Mallinckrodt, Merck KgA, Metron Technol, Millipore, MSP, Pall Europe, Philips Analyt, PMT Benelux, SEMI, Semitool, Sonosys, SOPRA, Tokyo Elektron Europe, ASM Int, IEEE, SCP Global Technol, Wacker Siltron DE dry residue; ICP-MS; SR-TXRF; TXRF; VPD; wafer surface ID X-RAY-FLUORESCENCE; REFLECTION AB TXRF, ICP-MS and SR-TXRF have been used for the quantification of trace metallic contaminants such as Cu, Ni in dry spots of a NIST solution on a Si wafer. It is found that the element combination influences the TXRF results in a dry residue. The results of Ni in a dry spot by TXRF can be well-quantified regardless the surface concentration if the dry spot contains Ni, Cu, Ti and Ca. However, the Ni results can suppress 50% if the dry spot contains 27 elements with 1 ng each. On the other hand, the Cu results can suppress 15% to >50% depending on the elemental combination and concentration of the dry spots. Noticeably however, at lower concentration, e.g.0.05 ng Cu, the "lower-than-expected" phenomenon no longer exists. A further investigation of the analysis of dry spot by SR-TXRF has shown that the Cu result at level of E9 atoms/cm(2) can be well quantified. C1 Balazs Analyt Lab, Sunnyvale, CA 94089 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Wang, J (reprint author), Balazs Analyt Lab, 252 Humboldt Court, Sunnyvale, CA 94089 USA. NR 8 TC 3 Z9 3 U1 0 U2 1 PU SCITEC PUBLICATIONS LTD PI UETIKON-ZUERICH PA BRANDRAIN 6, CH-8707 UETIKON-ZUERICH, SWITZERLAND SN 1012-0394 BN 3-908450-57-8 J9 SOL ST PHEN PY 2001 VL 76-77 BP 75 EP 79 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA BS04V UT WOS:000168449500019 ER PT S AU Omenetto, FG Yarotski, D Taylor, AJ AF Omenetto, FG Yarotski, D Taylor, AJ BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI Femtosecond pulse propagation in optical fibers SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer ID MU-M AB Femtosecond pulse propagation at 1.55 mum through a 90-meter link of single-mode optical fiber is analyzed. Observation and characterization of pulse evolution as a function of energy, distance, soliton formation and soliton self-frequency shift are shown. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Omenetto, FG (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MST-10,MSK764, Los Alamos, NM 87545 USA. RI Yarotski, Dmitry/G-4568-2010 NR 7 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 186 EP 188 PG 3 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300055 ER PT S AU Schoenlein, RW Chong, HHW Glovel, TE Heimann, PA Shank, CV Zholents, AA Zolotorev, MS AF Schoenlein, RW Chong, HHW Glovel, TE Heimann, PA Shank, CV Zholents, AA Zolotorev, MS BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI Femtosecond x-ray pulses from a synchrotron SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer ID RADIATION AB An important frontier in ultrafast science is the application of femtosecond x-ray pulses to the study of structural dynamics in condensed matter. We show that femtosecond laser pulses can be used to generate high-brightness, tunable, femtosecond x-ray pulses from a synchrotron. Performance of existing and proposed femtosecond x-ray beamlines at the Advanced Light Source synchrotron are discussed. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Schoenlein, RW (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Div Mat Sci, 1 Cyclotron Rd,MS 2-300, Berkeley, CA 94720 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 271 EP 275 PG 5 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300079 ER PT S AU Shvets, G Fisch, NJ Pukhov, A Meyer-ter-Vehn, J AF Shvets, G Fisch, NJ Pukhov, A Meyer-ter-Vehn, J BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI Pulse compression in plasma: Generation of femtosecond pulses without CPA SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer AB Laser pulses can be efficiently compressed to femto-second duration when a smaller-frequency short pulse collides with high frequency long pulse in a tenuous plasma, absorbing most of its energy. The mechanism of the short pulse amplification is the nonlinear superradiance. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Shvets, G (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 311 EP 313 PG 3 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300091 ER PT S AU Guo, C Rodriguez, G Taylor, AJ AF Guo, C Rodriguez, G Taylor, AJ BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI Resolving ultrafast dynamics of electron thermalization in gold using surface SHG SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer AB Using time-resolved surface second harmonic generation (SHG), an electron temperature dependent enhancement in the SHG signal is observed, for the first time in the high temperature regime, resolving the thermalization of nonequilibrium hot electrons. C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Guo, C (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. RI Rodriguez, George/G-7571-2012 OI Rodriguez, George/0000-0002-6044-9462 NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 413 EP 415 PG 3 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300120 ER PT S AU Thorsmolle, VK Averitt, RD Maley, MP Bulaevskii, LN Taylor, AJ AF Thorsmolle, VK Averitt, RD Maley, MP Bulaevskii, LN Taylor, AJ BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI Observation of the Josephson Plasma Resonance in Tl2Ba2CaCu2O8 using THz spectroscopy SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer AB Employing terahertz time-domain spectroscopy in transmission, we have unambiguously observed the Josephson Plasma Resonance in Tl2Ba2CaCu2O8 high-T-c thin films in zero magnetic field as a function of temperature. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Thorsmolle, VK (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 431 EP 433 PG 3 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300126 ER PT S AU Averitt, RD Lobad, AI Kwon, C Trugman, SA Thorsmolle, VK Taylor, AJ AF Averitt, RD Lobad, AI Kwon, C Trugman, SA Thorsmolle, VK Taylor, AJ BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI Ultrafast THz conductivity dynamics: spin-lattice relaxation in colossal magnetoresistive oxides SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer ID LA0.7CA0.3MNO3; LA1-XCAXMNO3; MAGNETISM AB Ultrafast measurements of optically induced changes in the conductivity (0.4-1.0 THz) of La0.7M0.3MnO3 films (M = Ca, Sr) from similar to 10K to similar to0.9T(c) reveal a spin-lattice relaxation that follows the temperature dependence of the spin specific heat. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Averitt, RD (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 434 EP 436 PG 3 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300127 ER PT S AU Savikhin, S Martinson, P Chitnis, P Johnson, W Xu, W Struve, W AF Savikhin, S Martinson, P Chitnis, P Johnson, W Xu, W Struve, W BE Elsaesser, T Mukamel, S Murnane, MM Scherer, NF TI The kinetics of primary electron transfer steps in PS-I reaction centers SO ULTRAFAST PHENOMENA XII SE SPRINGER SERIES IN CHEMICAL PHYSICS LA English DT Proceedings Paper CT 12th International Conference on Ultrafast Phenomena CY JUL 09-13, 2000 CL CHARLESTON, SC SP Opt Soc Amer AB The primary electron transfer kinetics were determined for the first time in core antenna - reaction center complexes from photosystem I of wild-type Synechocystis sp. PCC 6803 containing about 100 chlorophylls, by comparing femtosecond pump-probe profiles for samples with open and closed reaction centers. C1 Ames Lab, Ames, IA 50011 USA. RP Savikhin, S (reprint author), Ames Lab, Ames, IA 50011 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0172-6218 BN 3-540-41211-5 J9 SPRINGER SERIES CHEM PY 2001 VL 66 BP 662 EP 664 PG 3 WC Chemistry, Physical; Optics; Physics, Applied; Physics, Atomic, Molecular & Chemical SC Chemistry; Optics; Physics GA BR76M UT WOS:000167460300196 ER PT J AU Hoyt, PR Doktycz, MJ Warmack, RJ Allison, DP AF Hoyt, PR Doktycz, MJ Warmack, RJ Allison, DP TI Spin-column isolation of DNA-protein interactions from complex protein mixtures for AFM imaging SO ULTRAMICROSCOPY LA English DT Article; Proceedings Paper CT 2nd International Conference on Scanning Probe Microscopy, Sensors, and Nanostructures CY MAY 28-31, 2000 CL HEIDELBERG, GERMANY SP Ultramicroscopy DE atomic force microscopy; transcription factors; protein binding; DNA ID ATOMIC-FORCE MICROSCOPY; GEL-ELECTROPHORESIS; BINDING PROTEIN; RETARDATION AB Applications of atomic Force microscopy (AFM) to investigate structural-functional interactions between DNA and proteins, at the molecular level, should prove valuable for gaining a better understanding of gene expression. Specific genomic DNA-protein interactions occur within a sea of intracellular proteins. Successful AFM imaging requires isolating the specific DNA-protein complex free of background protein contamination. Using spin-column chromatography. we report the successful isolation and AFM imaging of transcription factor DNA complexes from DNA molecules incubated with crude cell lysates. This method should be applicable for the isolation and imaging of other specific DNA-protein complexes pertinent to functional genomic research. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37830 USA. RP Allison, DP (reprint author), Oak Ridge Natl Lab, Div Life Sci, Bldg 4500-S,MS 6123, Oak Ridge, TN 37830 USA. RI Doktycz, Mitchel/A-7499-2011 OI Doktycz, Mitchel/0000-0003-4856-8343 NR 16 TC 4 Z9 10 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JAN PY 2001 VL 86 IS 1-2 BP 139 EP 143 DI 10.1016/S0304-3991(00)00074-7 PG 5 WC Microscopy SC Microscopy GA 398AB UT WOS:000166730600017 PM 11215616 ER PT J AU Finot, E Thundat, T Lesniewska, E Goudonnet, JP AF Finot, E Thundat, T Lesniewska, E Goudonnet, JP TI Measuring magnetic susceptibilities of nanogram quantities of materials using microcantilevers SO ULTRAMICROSCOPY LA English DT Article; Proceedings Paper CT 2nd International Conference on Scanning Probe Microscopy, Sensors, and Nanostructures CY MAY 28-31, 2000 CL HEIDELBERG, GERMANY SP Ultramicroscopy DE microcantilever; atomic force microscopy; magnetic susceptibility; magnetic force ID FORCE MICROSCOPY; CANTILEVERS AB We describe a novel technique For measuring magnetic susceptibilities of nanogram quantities of magnetic materials that utilizes the extreme force sensitivity of microcantilevers. The magnetic force acting on samples attached to the free end of a cantilever can be measured as changes in the resonance response of the cantilever. The shift in resonance frequency of the cantilever is proportional to the field gradient, whereas the deflection of a cantilever is proportional to the magnetic force. The magnetic susceptibility measurement is based on comparison of the forces acting on the sample and a reference material in the same magnetic field and field gradient. We have determined the magnetic susceptibilities of nanogram quantities of many paramagnetic materials. The measured magnetic susceptibilities show excellent agreement with values found in the literature. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Univ Bourgogne, UMR CNRS 5027, Phys Lab LPUR, F-21011 Dijon, France. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. RP Finot, E (reprint author), Univ Bourgogne, UMR CNRS 5027, Phys Lab LPUR, BP 47870,9 Rue A Savary, F-21011 Dijon, France. RI Lesniewska, Eric/B-6523-2015 OI Lesniewska, Eric/0000-0002-8027-7223 NR 16 TC 17 Z9 19 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JAN PY 2001 VL 86 IS 1-2 BP 175 EP 180 DI 10.1016/S0304-3991(00)00080-2 PG 6 WC Microscopy SC Microscopy GA 398AB UT WOS:000166730600022 PM 11215621 ER PT J AU Datskos, PG Rajic, S Senesac, LR Datskou, I AF Datskos, PG Rajic, S Senesac, LR Datskou, I TI Fabrication of quantum well microcantilever photon detectors SO ULTRAMICROSCOPY LA English DT Article; Proceedings Paper CT 2nd International Conference on Scanning Probe Microscopy, Sensors, and Nanostructures CY MAY 28-31, 2000 CL HEIDELBERG, GERMANY SP Ultramicroscopy DE quantum well; photon detectors ID TECHNOLOGY; SILICON; STRESS; CAMERA AB We have developed a new method for fabricating quantum well microcantilever arrays that can be used in a variety of sensing applications. Microcantilevers with quantum wells allow real-time manipulation of energy states using external stress thus providing photon wavelength tunability. For example, this can result in an effective and rapid change in electron energy levels in photon detection devices. We applied this microfabrication technique to develop InSb microcantilevers and small arrays of GaAs/GaAlAs microcantilever quantum wells. Such arrays can be useful in the detection of infrared (IR) radiation at room temperature. (C) 2001 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tennessee, Knoxville, TN 37996 USA. Environm Engn Grp Inc, Knoxville, TN 37931 USA. RP Datskos, PG (reprint author), Oak Ridge Natl Lab, POB 2008,1 Bear Creek Rd, Oak Ridge, TN 37831 USA. NR 44 TC 17 Z9 18 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JAN PY 2001 VL 86 IS 1-2 BP 191 EP 206 DI 10.1016/S0304-3991(00)00072-3 PG 16 WC Microscopy SC Microscopy GA 398AB UT WOS:000166730600024 PM 11215623 ER PT S AU Holzrichter, MW Ladd, MD AF Holzrichter, MW Ladd, MD BE Carapezza, EM TI Using array processing to isolate seismic signals from noise and interferers of cultural origin SO UNATTENDED GROUND SENSOR TECHNOLOGIES AND APPLICATIONS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Unattended Ground Sensor Technologies and Applications III CY APR 18-19, 2001 CL ORLANDO, FL SP SPIE DE array processing; adaptive beamforming; cultural noise AB This paper examines the use of arrays of seismic sensors to enhance signals where multiple sources and an inhomogeneous medium complicate the received signal. Array processing is useful because it offers the opportunity to enhance SNR of the target signal while attenuating noise sources via spatiotemporal filtering. We used an adaptive beamforming algorithm to isolate the particular signal of interest from ambient noise and an interferer. The unpredictable nature of the noise and interferer environment was addressed by having the beamformer adapt to the environment. We present the results of using the beamformer on data from a thirty-geophone array. Initial results indicate inhomogeneities in the vacinity of the seismic sensors caused the significant perturbations to the wavefront. The adaptive algorithm was able to compensate for this and thereby performed better than the traditional delay-and-sum algorithm at isolating the target signal from the interfering signals. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Holzrichter, MW (reprint author), Sandia Natl Labs, POB 5800,MS 0859, Albuquerque, NM 87185 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4088-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4393 BP 69 EP 77 AR UNSP 4393-38 DI 10.1117/12.441273 PG 9 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BU10H UT WOS:000175016000008 ER PT S AU Rajic, S Datskos, PG AF Rajic, S Datskos, PG BE Carapezza, EM TI Integrated and simultaneous multiparameter sensing for tactical applications SO UNATTENDED GROUND SENSOR TECHNOLOGIES AND APPLICATIONS III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Unattended Ground Sensor Technologies and Applications III CY APR 18-19, 2001 CL ORLANDO, FL SP SPIE DE multiparameter; MEMS; sensor fusion; sensor integration; orthogonal stimuli ID MICROMECHANICAL SENSORS; FORCE MICROSCOPY; SURFACE STRESS; MICROCANTILEVERS; CANTILEVERS AB The sensor community has long been presented with the problem of prioritizing among several competing sensor system variables due to the inability to produce a high confidence, low-cost, reliable, and compact device. Typically a solution for very critical scenarios has been a high-cost scale reduction of larger more laboratory based instrumentation. This often produces data on a single parameter that is beyond reproach, however this can also produces a very delicate, bulky, and costly system often requiring a vacuum system of some sort. An alternative approach involves using micro-electro-mechanical systems (MEMS) based sensors. This typically results in low-cost and extremely compact devices that often produce dubious or insufficient data. Our approach integrates multiple orthogonal stimuli within a single chip to produce a MEMS based sensor that has a very high degree of signal confidence. Each individual sensed parameter may not produce vary high-confidence data, but the combination of multiple independent parameters significantly improves detection reliability in a small low-cost package. We believe that the integration of these parameters, and eventually many others, represents a major step in senor technology development since the senor fusion is inherent in the hardware of this low-cost single chip approach. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Rajic, S (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 21 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4088-4 J9 P SOC PHOTO-OPT INS PY 2001 VL 4393 BP 143 EP 152 AR UNSP 4393-22 DI 10.1117/12.441264 PG 10 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BU10H UT WOS:000175016000016 ER PT S AU Parker, LE Touzet, C AF Parker, LE Touzet, C BE Gerhart, GR Shoemaker, CM TI Multi-robot learning in an inherently cooperative task SO UNMANNED GROUND VEHICLE TECHNOLOGY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology III CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE multi-robot learning; cooperative. robotics; inherently cooperative tasks; distributed robotics AB An important need in multi-robot systems is the development of mechanisms that enable robot teams to autonomously generate cooperative behaviors. This paper first briefly presents the Cooperative Multi-robot Observation of Multiple Moving Targets (CMOMMT) application as a rich domain for studying the issues of multi-robot learning of new behaviors. We discuss the results of our hand-generated algorithm for CMOMMT, and then describe our research in generating multi-robot learning techniques for the CMOMMT application, comparing the results to the hand-generated solutions. Our results show that, while the learning approach performs better than random, naive approaches, much room still remains to match the results obtained from the hand-generated approach. The ultimate goal of this research is to develop techniques for multi-robot learning and adaptation that, will generalize to cooperative robot applications in many domains., thus facilitating the practical use of multi-robot teams in a wide variety of real-world applications. C1 Oak Ridge Natl Lab, Div Math & Comp Sci, Ctr Engn Sci Adv Res, Oak Ridge, TN 37831 USA. RP Parker, LE (reprint author), Oak Ridge Natl Lab, Div Math & Comp Sci, Ctr Engn Sci Adv Res, Oak Ridge, TN 37831 USA. NR 15 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4059-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4364 BP 127 EP 135 DI 10.1117/12.439972 PG 9 WC Computer Science, Artificial Intelligence; Robotics; Transportation Science & Technology SC Computer Science; Robotics; Transportation GA BT28L UT WOS:000172533400014 ER PT S AU Feddema, J Schoenwald, D AF Feddema, J Schoenwald, D BE Gerhart, GR Shoemaker, CM TI Decentralized control of cooperative robotic vehicles SO UNMANNED GROUND VEHICLE TECHNOLOGY III SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology III CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE mobile robotics; cooperative control; decentralized control ID NONHOLONOMIC MOBILE ROBOTS; BEHAVIOR AB This paper describes how decentralized control theory can be used to control multiple cooperative robotic vehicles. Models of cooperation are discussed and related to the input/output reachability and structural observability and controllability of the entire system. Whereas decentralized control research in the past has concentrated on using decentralized controllers to partition complex physically interconnected systems, this work uses decentralized methods to connect otherwise independent non-touching robotic vehicles so that they behave in a stable, coordinated fashion. A vector Liapunov method is used to prove stability of a single example: the controlled motion of multiple vehicles along a line. The results of this stability analysis have been implemented on two applications: a robotic perimeter surveillance system and self-heating minefield. C1 Sandia Natl Labs, Intelligent Syst & Robot Ctr, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Intelligent Syst & Robot Ctr, POB 5800, Albuquerque, NM 87185 USA. NR 31 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4059-0 J9 PROC SPIE PY 2001 VL 4364 BP 136 EP 146 DI 10.1117/12.439973 PG 11 WC Computer Science, Artificial Intelligence; Robotics; Transportation Science & Technology SC Computer Science; Robotics; Transportation GA BT28L UT WOS:000172533400015 ER PT S AU Lewis, C Feddema, J Klarer, P AF Lewis, C Feddema, J Klarer, P BE Gerhart, GR Shoemaker, CM TI Tasking and control of a squad of robotic vehicles SO UNMANNED GROUND VEHICLE TECHNOLOGY III SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology III CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE cooperative robotic vehicles ID NONHOLONOMIC MOBILE ROBOTS AB Sandia National Laboratories have developed a squad of robotic vehicles as a test-bed for investigating cooperative control strategies. The squad consists of eight RATLER (TM) vehicles and a command station. The RATLERs (TM) are medium-sized all-electric vehicles containing a PC104 stack for computation, control, and sensing. Three separate RF channels are used for communications; one for video, one for command and control, and one for differential GPS corrections. Using DGPS and IR proximity sensors, the vehicles are capable of autonomously traversing fairly rough terrain. The control station is a PC running Windows (TM) NT. A GUI has been developed that allows a single operator to task and monitor all eight vehicles. To date, the following mission capabilities have been demonstrated: 1. Way-Point Navigation, 2. Formation Following, 3. Perimeter Surveillance, 4. Surround and Diversion, and 5. DGPS Leap Frog. This paper describes the system and briefly outlines each mission capability. The DGPS Leap Frog capability is discussed in more detail. This capability is unique in that it demonstrates how cooperation allows the vehicles to accurately navigate beyond the RF communication range. One vehicle stops and uses its corrected GPS position to re-initialize its receiver to become the DGPS correction station for the other vehicles. Error in position accumulates each time a new vehicle takes over the DGPS duties. The accumulation in error is accurately modeled as a random walk phenomenon. This paper demonstrates how useful accuracy can be maintained beyond the vehicle's range. C1 Sandia Natl Labs, Intelligent Syst & Robot Ctr, Livermore, CA 94550 USA. RP Sandia Natl Labs, Intelligent Syst & Robot Ctr, Livermore, CA 94550 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4059-0 J9 PROC SPIE PY 2001 VL 4364 BP 147 EP 158 DI 10.1117/12.439974 PG 12 WC Computer Science, Artificial Intelligence; Robotics; Transportation Science & Technology SC Computer Science; Robotics; Transportation GA BT28L UT WOS:000172533400016 ER PT S AU Dudenhoeffer, DD Bruemmer, DJ Anderson, MO McKay, MD AF Dudenhoeffer, DD Bruemmer, DJ Anderson, MO McKay, MD BE Gerhart, GR Shoemaker, CM TI Development and implementation of large-scale micro-robotic forces using formation behaviors SO UNMANNED GROUND VEHICLE TECHNOLOGY III SE Proceedings of SPIE LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology III CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE robot; social potential field; online learning; swarm behavior; distributed robotics; DOE; RIM AB Micro-robots may soon be available for deployment by the thousands. Consequently, controlling and coordinating a force this large to accomplish a prescribed task is of great interest. This paper describes a flexible architecture for deploying thousands of autonomous robots simultaneously. The robots' behavior is based on a subsumption architecture in which individual behaviors are prioritized with respect to all others. The primary behavior explored in this paper is group formation behavior drawn from the work in social potential fields applications conducted by Reif and Wang(1), and Dudehoeffer and Jones.(2) While many papers have examined the application of social potential fields in a simulation environment, this paper describes the implementation of this behavior in a collective of small robots. C1 INEEL, Idaho Falls, ID 83415 USA. RP INEEL, POB 1625, Idaho Falls, ID 83415 USA. EM dudedd@inel.gov; bruedj@inel.gov; matthew@inel.gov; mark@inel.gov NR 10 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4059-0 J9 PROC SPIE PY 2001 VL 4364 BP 159 EP 168 DI 10.1117/12.439975 PG 10 WC Computer Science, Artificial Intelligence; Robotics; Transportation Science & Technology SC Computer Science; Robotics; Transportation GA BT28L UT WOS:000172533400017 ER PT S AU Harrigan, RW Bennett, PC AF Harrigan, RW Bennett, PC BE Gerhart, GR Shoemaker, CM TI Making remote manipulators easy to use SO UNMANNED GROUND VEHICLE TECHNOLOGY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology III CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE robot; manipulation; operator-supervised; shared control; operator performance AB Perhaps the most basic barrier to the widespread deployment of remote manipulators is that they are very difficult to use. Remote manual operations are fatiguing and tedious, while fully autonomous systems are seldom able to function in changing and unstructured environments. An alternative approach to these extremes is to exploit computer control while leaving the operator in the loop to take advantage of the operator's perceptual and decision-making capabilities. This paper describes research that is enabling gradual introduction of computer control and decision making into operator-supervised robotic manipulation systems. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Harrigan, RW (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4059-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4364 BP 169 EP 179 DI 10.1117/12.439976 PG 11 WC Computer Science, Artificial Intelligence; Robotics; Transportation Science & Technology SC Computer Science; Robotics; Transportation GA BT28L UT WOS:000172533400018 ER PT S AU Knee, HE Gorsich, DJ AF Knee, HE Gorsich, DJ BE Gerhart, GR Shoemaker, CM TI Vehicle intelligence and implications for robotics SO UNMANNED GROUND VEHICLE TECHNOLOGY III SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Unmanned Ground Vehicle Technology III CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE AB Significant progress has been made with regard to bringing vehicle intelligence (VI) technologies into passenger, commercial, and military ground vehicles. Very few of these technologies, however, directly impact vehicle control systems; and although the U.S. Department of Transportation's (DOT's) Automated Highway System (AHS) portion of its Intelligent Systems (ITS) Program, successfully demonstrated fully-automated driving in August, 1997, most of the ITS technologies developed to date have focused on driver warning/information systems. The U.S. Department of Defense's (DOD's) Army Vehicle Intelligence Program (AVIP) is capitalizing on the lessons learned from DOT's ITS Program, and will push the envelope for selected technologies, including issues of vehicle control. As VI impinges more heavily on vehicle control, it will be beneficial to consider more closely the relationship between VI and robotics. Because a significant amount of data related to the driver, vehicle, and driving environment are already captured and managed by on-board VI systems, a rich database of information is available that would be of value for automating (or roboticizing) driver/driving functions and tasks. This paper will discuss some state-of-the-art VI technologies and will suggest how greater benefits could be achieved by examining the relationship between VI and robotics. C1 Oak Ridge Natl Lab, Natl Transportat Res Ctr, Knoxville, TN 37932 USA. RP Knee, HE (reprint author), Oak Ridge Natl Lab, Natl Transportat Res Ctr, 2360 Cherahala Blvd, Knoxville, TN 37932 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4059-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4364 BP 180 EP 191 DI 10.1117/12.439977 PG 12 WC Computer Science, Artificial Intelligence; Robotics; Transportation Science & Technology SC Computer Science; Robotics; Transportation GA BT28L UT WOS:000172533400019 ER PT J AU Davis, R De La Parra, C Hseuh, HC Mickaliger, P Pate, DJ AF Davis, R De La Parra, C Hseuh, HC Mickaliger, P Pate, DJ TI Measurement of helium leak rates with temperature and pressure in RHIC SO VACUUM LA English DT Article; Proceedings Paper CT 6th European Vacuum Conference CY DEC 07-10, 1999 CL VILLURBANNE, FRANCE ID VACUUM AB The changes in helium leak rates with pressure and temperature from helium-cooled magnet vessels into insulating vacuum were measured. The leak rates increased by three orders of magnitude when the vessels were cooled from ambient temperature to 4.5 K. The changes in leak rates were found to be smaller than those of a Viscous flow through a capillary tube. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Brookhaven Natl Lab, Collider Accelerator Dept, Upton, NY 11973 USA. RP Hseuh, HC (reprint author), Brookhaven Natl Lab, Collider Accelerator Dept, Bldg 817, Upton, NY 11973 USA. NR 9 TC 2 Z9 2 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0042-207X J9 VACUUM JI Vacuum PD JAN-FEB PY 2001 VL 60 IS 1-2 BP 131 EP 135 DI 10.1016/S0042-207X(00)00365-1 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 388XC UT WOS:000166207500019 ER PT S AU Foster, I Kesselman, C AF Foster, I Kesselman, C BE Palma, JML Dongarra, J Hernandez, V TI Computational grids - Invited talk (Reprinted from The Grid: Blueprint for a new computing infrastructure, 1998) SO VECTOR AND PARALLEL PROCESSING - VECPAR 2000 SE LECTURE NOTES IN COMPUTER SCIENCE LA English DT Reprint CT 4th International Conference on Vector and Parallel Processing (VECPAR 2000) CY JUN 21-23, 2000 CL OPORTO, PORTUGAL SP Univ Porto, Fac Engenharia, FCT, European Off Aerosp Res & Dev, FACM, FCCN, FCG, Camara Municipal Porto, Int British Council, Porto Convent Bur, Alcatel, CISCO Syst, Compaq, Microsoft, NEC, Nortel Newworks, Siemens ID GROUP COMMUNICATION-SYSTEM; DESIGN AB In this introductory chapter, we lay the groundwork for the rest of the book by providing a more detailed picture of the expected purpose, shape, and architecture of future grid systems. We structure the chapter in terms of six questions that we believe are central to this discussion: Why do we need computational grids? What types of applications will grids be used for? Who will use grids? How will grids be used? What is involved in building a grid? And, what problems must be solved to make grids commonplace? We provide an overview of each of these issues here, referring to subsequent chapters for more detailed discussion. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ So Calif, Inst Informat Sci, Marina Del Rey, CA 90292 USA. RP Foster, I (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Kesselman, Carl/0000-0003-0917-1562 NR 75 TC 6 Z9 6 U1 1 U2 4 PU SPRINGER-VERLAG BERLIN PI BERLIN PA HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY SN 0302-9743 BN 3-540-41999-3 J9 LECT NOTES COMPUT SC PY 2001 VL 1981 BP 3 EP 37 PG 35 WC Computer Science, Software Engineering; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BT84D UT WOS:000174201100001 ER PT B AU Nelson, CS Zimmermann, MV Hill, JP Gibbs, D Kiryukhin, V Koo, TY Cheong, SW AF Nelson, CS Zimmermann, MV Hill, JP Gibbs, D Kiryukhin, V Koo, TY Cheong, SW BE Kaplan, MD Zimmerman, GO TI X-ray scattering studies of correlated polarons in La0.7Ca0.3MnO3 SO VIBRONIC INTERACTIONS: JAHN-TELLER EFFECT IN CRYSTALS AND MOLECULES SE NATO SCIENCE SERIES, SERIES II: MATHEMATICS, PHYSICS AND CHEMISTRY LA English DT Proceedings Paper CT NATO Advanced Research Workshop on Colossal Magnetoresistance and Vibronic Interactions/15th International Jahn-Teller Symposium CY AUG 16-22, 2000 CL BOSTON, MA SP Boston Univ, Simmons Coll, NATO Sci Div ID COLOSSAL-MAGNETORESISTANCE; OXIDE LA0.7CA0.3MNO3; DIFFUSE-SCATTERING; MANGANITES; LA1-XCAXMNO3; COLLAPSE AB We report x-ray scattering studies of diffuse peaks in the paramagnetic insulating phase of La0.7Ca0.3MnO3. The peaks occur at a (0.5 0 0)/(0 0.5 0)-type wavevector, and are found to disappear abruptly upon cooling through the transition into the ferromagnetic metallic phase. Based on the wavevector and measured correlation length of 1-2 lattice constants, the peaks are found to be consistent with the formation of CE-type bipolarons, and their collapse at T-c is attributed to the energy gain associated with itineracy in the ferromagnetic state. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Nelson, CS (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 18 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS BN 1-4020-0044-8 J9 NATO SCI SER II MATH PY 2001 VL 39 BP 209 EP 213 PG 5 WC Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter SC Physics GA BU59V UT WOS:000176465400022 ER PT B AU Kent, S AF Kent, S BE Brunner, RJ Djorjovski, SG Szalay, AS TI Precision galactic structure SO VIRTUAL OBSERVATORIES OF THE FUTURE, PROCEEDINGS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Conference on Virtual Observatories of the Future CY JUN 13-16, 2000 CL CALIF INST TECHNOL, PASADENA, CA SP Natl Sci Fdn, Natl Aeronaut & Space Adm, Sun Microsyst & Microsoft Res HO CALIF INST TECHNOL AB Optical and IR surveys in progress or in the planning stages will lead to substantial improvements in our picture of the Milky Way as a consequence of their providing large volumes of data with much improved photometric and positional measurements compared with existing datasets. C1 Fermilab, Batavia, IL 60510 USA. RP Kent, S (reprint author), Fermilab, POB 500, Batavia, IL 60510 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-057-9 J9 ASTR SOC P PY 2001 VL 225 BP 40 EP 45 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS48T UT WOS:000170040800006 ER PT S AU Schlei, BR Prasad, L Skourikhine, AN AF Schlei, BR Prasad, L Skourikhine, AN BE Latecki, LJ Mount, DM Wu, AY Melter, RA TI Geometric morphology of cellular solids SO VISION GEOMETRY X SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Vision Geometry X CY JUL 29-30, 2001 CL SAN DIEGO, CA SP SPIE AB We demonstrate how to derive morphological information from micrographs, i.e., grey-level images, of polymeric foams. The segmentation of the images is performed by applying a pulse-coupled neural network. This processing generates blobs of the foams walls/struts and voids, respectively. The contours of the blobs and their corresponding points form the input to a constrained Delaunay tessellation, which provides an unstructured grid of the material under consideration. The subsequently applied Chordal Axis Transform captures the intrinsic shape characteristics, and facilitates the identification and localization of key morphological features. While stochastic features of the polymeric foams struts/walls such as areas, aspect ratios, etc., already can be computed at this stage, the foams voids require further geometric processing. The voids are separated into single foam cells. This shape manipulation leads to a refinement of the initial blob contours, which then requires the repeated application of the constrained Delaunay tessellation and Chordal Axis Transform, respectively. Using minimum enclosing rectangles for each foam cell, finally the stochastic features of the foam voids are computed. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Schlei, BR (reprint author), Los Alamos Natl Lab, Div Theoret, T-1,MS B221, Los Alamos, NM 87545 USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4190-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4476 BP 73 EP 79 AR UNSP 4476-09 DI 10.1117/12.447289 PG 3 WC Mathematics, Applied; Optics; Imaging Science & Photographic Technology SC Mathematics; Optics; Imaging Science & Photographic Technology GA BU15B UT WOS:000175161800008 ER PT J AU Gong, G Parvin, B AF Gong, G Parvin, B TI Robust and efficient surface reconstruction from contours SO VISUAL COMPUTER LA English DT Article DE infinity Laplacian equation; shape from contour; shape from slices; surface reconstruction ID PLANAR CROSS-SECTIONS; SHAPE RECONSTRUCTION; TRIANGULATION; ALGORITHM AB We propose a new approach for surface recovery from planar sectional contours. The surface is reconstructed based on the so-called "equal importance criterion," which suggests that every point in the region contributes equally to the reconstruction process. The problem is then formulated in terms of a partial differential equation, and the solution is efficiently calculated from distance transformation. To make the algorithm valid for different application purposes, both the isosurface and the primitive representations of the object surface are derived. The isosurface is constructed by means of a partial differential equation, which can be solved iteratively. The traditional distance interpolating method, which was used by several researchers for surface reconstruction, is an approximate solution of the equation. The primitive representations are approximated by Voronoi diagram transformation of the surface space. Isosurfaces have the advantage that subsequent geometric analysis of the object can be easily carried out while primitive representation is easy to visualize. The proposed technique allows for surface recovery at any desired resolution, thus avoiding the inherent problems of correspondence, tiling, and branching. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. RP Gong, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Energy Res Sci Comp Ctr, MS 50B-2239,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 37 TC 8 Z9 12 U1 0 U2 1 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0178-2789 J9 VISUAL COMPUT JI Visual Comput. PY 2001 VL 17 IS 4 BP 199 EP 208 DI 10.1007/PL00013409 PG 10 WC Computer Science, Software Engineering SC Computer Science GA 443AE UT WOS:000169316500001 ER PT S AU McGuigan, M Smith, G Spiletic, J Fine, V Nevski, P Longacre, R Thomas, J AF McGuigan, M Smith, G Spiletic, J Fine, V Nevski, P Longacre, R Thomas, J BE Erbacher, RF Chen, PC Roberts, JC Wittenbrink, CM Grohn, M TI Development of software tools for visualization of high energy and nuclear physics SO VISUAL DATA EXPLORATION AND ANALYSIS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 8th Meeting of the Visual Data Exploration and Analysis Conference CY JAN 22-23, 2001 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE AB We discuss the development of software tools involved in the visualization of simulations, detectors and events used in high energy and nuclear physics experiments taking place at large particle accelerators. Two such accelerators are Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab completed in 1999 and the Large Hadron Collider (LHC) at CERN to be completed in 2005. One primary goal of RHIC is the formation of a quark-gluon plasma, a state of matter thought to exist shortly after the big bang. We discuss a simulation and visualization of the collision at RHIC of two gold nuclei and the predicted results for the quark-gluon plasma calculated using the parton cascade model. ATLAS is a large detector with 20 million separate elements being constructed to measure physics beyond the standard Model at the LHC. A high end visual display for ATLAS is necessary because of the sheer size and complexity of the detector. To load, rotate, query, and debug simulation code with a modern detector simply takes too long even on a powerful work station. We develop a visual display of HENP detectors on BNL multiprocessor visualization server at multiple level of detail. We work with general and generic detector framework consistent with ROOT, GAUDI etc. We enable collaborative viewing of detector and events by directly running the analysis in BNL stereoscopic theatre. We obtain real time visual display for events accumulated during simulations. C1 Brookhaven Natl Lab, Div Informat Technol, Upton, NY 11973 USA. RP McGuigan, M (reprint author), Brookhaven Natl Lab, Div Informat Technol, Upton, NY 11973 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3980-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4302 BP 242 EP 250 DI 10.1117/12.424935 PG 9 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BS55Q UT WOS:000170315300025 ER PT S AU Keahey, TA McCormick, P Ahrens, J Keahey, K AF Keahey, TA McCormick, P Ahrens, J Keahey, K BE Erbacher, RF Chen, PC Roberts, JC Wittenbrink, CM Grohn, M TI Qviz: A framework for querying and visualizing data SO VISUAL DATA EXPLORATION AND ANALYSIS VIII SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 8th Meeting of the Visual Data Exploration and Analysis Conference CY JAN 22-23, 2001 CL SAN JOSE, CA SP Soc Imaging Sci & Technol, SPIE DE data visualization; analytical queries; parallel processing; multivariate visualization AB Qviz is a lightweight, modular,and easy to use parallel system for interactive analytical query processing and visual presentation of large datasets. Qviz allows queries of arbitrary complexity to be easily constructed using a specialized scripting language. Visual presentation of the results is also easily achieved via simple scripted and interactive commands to our query-specific visualization tools. This paper describes our initial experiences with the Qviz system for querying and visualizing scientific datasets, showing how Qviz has been used in two different applications: ocean modeling and linear accelerator simulations. C1 Los Alamos Natl Lab, Adv Comp Grp, Los Alamos, NM 87545 USA. RP Keahey, TA (reprint author), Los Alamos Natl Lab, Adv Comp Grp, Los Alamos, NM 87545 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3980-0 J9 P SOC PHOTO-OPT INS PY 2001 VL 4302 BP 259 EP 267 DI 10.1117/12.424937 PG 9 WC Optics; Imaging Science & Photographic Technology SC Optics; Imaging Science & Photographic Technology GA BS55Q UT WOS:000170315300027 ER PT S AU Lindstrom, P Silva, CT AF Lindstrom, P Silva, CT BE Ertl, T Joy, K Varshney, A TI A memory insensitive technique for large model simplification SO VISUALIZATION 2001, PROCEEDINGS SE IEEE CONFERENCE ON VISUALIZATION LA English DT Proceedings Paper CT IEEE Visualization Conference CY OCT 21-26, 2001 CL SAN DIEGO, CA SP IEEE Comp Soc, Tech Comm Visualizat & Graph, ACM SIGGRAPH DE polygonal surface simplification; large data; out-of-core algorithms; external sorting; quadric error metrics AB In this paper we propose three simple, but significant improvements to the OoCS (Out-of-Core Simplification) algorithm of Lindstrom [20] which increase the quality of approximations and extend the applicability of the algorithm to an even larger class of compute systems. The original OoCS algorithm has memory complexity that depends on the size of the output mesh. but no dependency on the size of the input mesh, That is, it can be used to simplify meshes of arbitrarily large size, but the complexity of the output mesh is limited by the amount of memory available. Our first contribution is a version of OoCS that removes the dependency of having enough memory to hold (even) the simplified mesh. With our new algorithm. the whole process is made essentially independent of the available memory on the host computer. Our new technique uses disk instead of main memory, but it is carefully designed to avoid costly random accesses. Our two other contributions improve the quality of the approximations generated by OoCS. We propose a scheme for preserving surface boundaries which does not use connectivity information, and a scheme for constraining the position of the "representative vertex" of a grid cell to an optimal position inside the cell. C1 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. RP Lindstrom, P (reprint author), Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, 7000 E Ave,L-560, Livermore, CA 94551 USA. OI Lindstrom, Peter/0000-0003-3817-4199 NR 32 TC 37 Z9 40 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1070-2385 BN 0-7803-7200-X J9 IEEE VISUAL PY 2001 BP 121 EP 126 DI 10.1109/VISUAL.2001.964502 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BT78K UT WOS:000174051300014 ER PT S AU Lindstrom, P Pascucci, V AF Lindstrom, P Pascucci, V BE Ertl, T Joy, K Varshney, A TI Visualization of large terrains made easy SO VISUALIZATION 2001, PROCEEDINGS SE IEEE CONFERENCE ON VISUALIZATION LA English DT Proceedings Paper CT IEEE Visualization Conference CY OCT 21-26, 2001 CL SAN DIEGO, CA SP IEEE Comp Soc, Tech Comm Visualizat & Graph, ACM SIGGRAPH AB We present an elegant and simple to implement framework for performing out-of-core visualization and view-dependent refinement of large terrain surfaces. Contrary to the recent trend of increasingly elaborate algorithms for large-scale terrain visualization, our algorithms and data structures have been designed with the primary goal of simplicity and efficiency of implementation. Our approach to managing large terrain data also departs from more conventional strategies based on data tiling, Rather than emphasizing how to segment and efficiently bring data in and out of memory, we focus on the manner in which the data is laid out to achieve good memory coherency for data accesses made in a top-down (coarse-to-fine) refinement of the terrain. We present and compare the results of using several different data indexing schemes, and propose a simple to compute index that yields substantial improvements in locality and speed over more commonly used data layouts. Our second contribution is a new and simple, yet easy to generalize method for view-dependent refinement. Similar to several published methods in this area, we use longest edge bisection in a top-down traversal of the mesh hierarchy to produce a continuous surface with subdivision connectivity. In tandem with the refinement, we perform view frustum culling and triangle stripping. These three components are done together in a single pass over the mesh. We show how this framework supports virtually any error metric. while still being highly memory and compute efficient. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Lindstrom, P (reprint author), 7000 East Ave,L-560, Livermore, CA 94551 USA. OI Lindstrom, Peter/0000-0003-3817-4199 NR 26 TC 95 Z9 144 U1 0 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1070-2385 BN 0-7803-7200-X J9 IEEE VISUAL PY 2001 BP 363 EP 370 DI 10.1109/VISUAL.2001.964533 PG 8 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BT78K UT WOS:000174051300045 ER PT S AU Crossno, P Haynes, R AF Crossno, P Haynes, R BE Ertl, T Joy, K Varshney, A TI Case study: Visual debugging of cluster hardware SO VISUALIZATION 2001, PROCEEDINGS SE IEEE CONFERENCE ON VISUALIZATION LA English DT Proceedings Paper CT IEEE Visualization Conference CY OCT 21-26, 2001 CL SAN DIEGO, CA SP IEEE Comp Soc, Tech Comm Visualizat & Graph, ACM SIGGRAPH DE visual debugging; hardware modeling; design analysis; performance optimization ID PARALLEL AB This paper presents a novel use of visualization applied to debugging the Cplant(TM) cluster hardware at Sandia National Laboratories, As commodity cluster systems grow in popularity and grow in size, tracking component failures within the hardware will become more and more difficult, We have developed a tool that facilitates visual debugging of errors within the switches and cables connecting the processors. Combining an abstract system model with color-coding for both error and job information enables failing components to be identified. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Crossno, P (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1070-2385 BN 0-7803-7200-X J9 IEEE VISUAL PY 2001 BP 429 EP 432 DI 10.1109/VISUAL.2001.964543 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BT78K UT WOS:000174051300054 ER PT S AU Koegler, WS AF Koegler, WS BE Ertl, T Joy, K Varshney, A TI Case study: Aapplication of feature tracking to analysis of autoignition simulation data SO VISUALIZATION 2001, PROCEEDINGS SE IEEE CONFERENCE ON VISUALIZATION LA English DT Proceedings Paper CT IEEE Visualization Conference CY OCT 21-26, 2001 CL SAN DIEGO, CA SP IEEE Comp Soc, Tech Comm Visualizat & Graph, ACM SIGGRAPH DE feature detection; feature tracking; combustion; autoignition AB The focus of this paper is to evaluate the usefulness of some basic feature tracking algorithms as analysis tools for combustion datasets by application to a dataset modeling autoignition. Features defined as areas of high intermediate concentrations were examined to explore the initial phases in the autoigniton process. C1 Sandia Natl Labs, Livermore, CA USA. RP POB 969,MS 9051, Livermore, CA 94551 USA. EM wkoegle@ca.sandia.gov NR 7 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1070-2385 BN 0-7803-7200-X J9 IEEE VISUAL PY 2001 BP 461 EP 464 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BT78K UT WOS:000174051300062 ER PT S AU Ward, RC Kruse, KL Allgood, GO Hively, LM Fischer, KN Munro, NB Easterly, CE AF Ward, RC Kruse, KL Allgood, GO Hively, LM Fischer, KN Munro, NB Easterly, CE BE Allgood, GO Faust, NL TI Virtual human project SO VISUALIZATION OF TEMPORAL AND SPATIAL DATA FOR CIVILIAN AND DEFENSE APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Visualization of Temporal and Spatial Data for Civilian and Defense Applications CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE problem solving environment; extensible markup language; physiological model; non-uniform rational B-splines; lung sounds; respiratory system AB This paper describes the development of a comprehensive human modeling environment, the Virtual Human, which will be used initially to model the human respiratory system for purposes of predicting pulmonary disease or injury using lung sounds. The details of the computational environment, including the development of a Virtual Human Thorax, a database for storing models, model parameters, and experimental data, and a Virtual Human web interface are outlined. Preliminary progress in developing this environment will be presented. A separate paper at the conference describes the modeling of sound generation using computational fluid dynamics and the modeling of sound propagation in the human respiratory system. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ward, RC (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 8 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4063-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4368 BP 158 EP 167 DI 10.1117/12.438121 PG 10 WC Computer Science, Artificial Intelligence; Engineering, Biomedical; Optics; Imaging Science & Photographic Technology SC Computer Science; Engineering; Optics; Imaging Science & Photographic Technology GA BT24V UT WOS:000172421100019 ER PT S AU Kruse, KL Williams, PT Allgood, GO Ward, RC Gleason, SS Paulus, MJ Munro, NB AF Kruse, KL Williams, PT Allgood, GO Ward, RC Gleason, SS Paulus, MJ Munro, NB BE Allgood, GO Faust, NL TI Flow simulation in a 3-D model of pig airways and connection to lung sounds SO VISUALIZATION OF TEMPORAL AND SPATIAL DATA FOR CIVILIAN AND DEFENSE APPLICATIONS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Visualization of Temporal and Spatial Data for Civilian and Defense Applications CY APR 16-17, 2001 CL ORLANDO, FL SP SPIE DE computational fluid dynamics; airflow; lungs; modeling; virtual human ID TREE AB Fundamental to the understanding of the various transport processes within the respiratory system. airway fluid dynamics plays an important role in biomedical research. When air flows through the respiratory tract, it is constantly changing direction through a complex system of curved and bifurcating tubes. As a result, numerical simulations of the airflow through this tracheobronchial system must be capable of resolving such fluid dynamic phenomena as flow separation, recirculation, secondary flows due to centrifugal instabilities (Dean flows), and shear stress variation along the airway surface. Anatomic complexities within the tracheobronchial tree, such as sharp carinal regions at asymmetric bifurcations, have motivated the application of the incompressible Computational Fluid Dynamics code PHI3D to the modeling of airflow. Developed at ORNL, PHI3D implements the new Continuity Constraint Method (CCM). Using a finite-element methodology, complex geometries can be easily simulated with PHI3D using unstructured grids. A time-accurate integration scheme allows the simulation of both transient and steady-state flows. A realistic geometry model of the central airways for the fluid flow studies was obtained from pig lungs using a new high resolution x-ray computed tomography (MicroCAT) system developed at ORNL for generating 3-D images of the internal structure of laboratory animals. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Kruse, KL (reprint author), Oak Ridge Natl Lab, POB 2008,MS-6418, Oak Ridge, TN 37831 USA. NR 22 TC 2 Z9 2 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4063-9 J9 P SOC PHOTO-OPT INS PY 2001 VL 4368 BP 168 EP 176 DI 10.1117/12.438122 PG 9 WC Computer Science, Artificial Intelligence; Engineering, Biomedical; Optics; Imaging Science & Photographic Technology SC Computer Science; Engineering; Optics; Imaging Science & Photographic Technology GA BT24V UT WOS:000172421100020 ER PT J AU Wang, Z Moore, RC Felmy, AR Mason, MJ Kukkadapu, RK AF Wang, Z Moore, RC Felmy, AR Mason, MJ Kukkadapu, RK TI A study of the corrosion products of mild steel in high ionic strength brines SO WASTE MANAGEMENT LA English DT Article DE corrosion; in situ AFM; green rust; nuclear waste; iron oxide; brine ID ZERO-VALENT IRON; URANIUM REMOVAL; GROUNDWATER AB The corrosion layer on steel surfaces that formed after exposure to waste isolation pilot plant (WIPP) brines under anoxic conditions was characterized for chemical composition, thickness and phase composition. The chemical composition of the corrosion layer was determined both by X-ray photoelectron spectroscopy (XPS) and by chemical analysis of acid solutions used to remove the corrosion layer. Atomic force microscopic (AFM) images indicated that the brine-corroded surface layer shows extensive granulation along the contours of the steel surface that is characteristic of sharp polishing marks. The corrosion layer seemed to be porous and could be dissolved and detached in dilute hydrochloric acid. The corrosion layer appears to be composed of iron oxides with some ionic substitutions from the brines. The 77 K Mossbauer spectrum recorded for iron powder leached under similar conditions indicated the corrosion layer was comprised principally of green rust. Published by Elsevier Science Ltd. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Wang, Z (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Wang, Zheming/E-8244-2010 OI Wang, Zheming/0000-0002-1986-4357 NR 12 TC 5 Z9 5 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-053X J9 WASTE MANAGE JI Waste Manage. PY 2001 VL 21 IS 4 BP 335 EP 341 DI 10.1016/S0956-053X(00)00058-1 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 411HK UT WOS:000167492300004 PM 11300533 ER PT J AU Brey, RR Rodriguez, R Harmon, JF Winston, P AF Brey, RR Rodriguez, R Harmon, JF Winston, P TI Investigation of irradiated soil byproducts SO WASTE MANAGEMENT LA English DT Article DE radiation fields; irradiated soils; clay soils; nuclear fuel; explosives ID GAMMA-IRRADIATION; HYDROGEN; WATER AB The high dose irradiation of windblown soil deposited onto the surface of spent nuclear fuel is of concern to long-term fuel storage stability. Such soils could be exposed to radiation fields as great as 1.08 x 10(-3) C/kg-s (15,000 R/hr) during the 40-year anticipated period of interim dry storage prior to placement at the proposed national repository. The total absorbed dose in these cases could be as high as 5 x 10(7) Gy (5 x 10(9) rads). This investigation evaluated the potential generation of explosive or combustible irradiation byproducts during this irradiation. It focuses on the production of radiolytic byproducts generated within the pore water of surrogate clays that are consistent with those found on the Idaho National Engineering and Environmental Laboratory. Synthesized surrogates of localized soils containing combinations of clay, water, and aluminum samples, enclosed within a stainless steel vessel were irradiated and the quantities of the byproducts generated measured. Two types of clays, varying primarily in the presence of iron oxide, were investigated. Two treatment levels of irradiation and a control were investigated. An 18-Mev linear accelerator was used to irradiate samples. The first irradiation level provided an absorbed dose of 3.9x10(5)+/-1.4x10(5)Gy (3.9x10(7)+/-1.4x10(7) rads) in a 3-h period. At the second irradiation level, 4.8x10(5)+/-2.0x10(5)Gy (4.8x10(7)+/-2.0x10(7) rads) were delivered in a 6-h period. When averaged over all treatment parameters, irradiated clay samples with and without iron (III) oxide (moisture content=40%) had a production rate of hydrogen gas that was a strong function of radiation-dose. A g-value of 5.61x10(-9)+/-1.56x10(-9) mol/J (0.054 +/-0.015 molecules/100-eV) per mass of pore water was observed in the clay samples without iron (III) oxide for hydrogen gas production. A g-value of 1.07 x 10-8f2.91x10(-9) mol/J (0.103 +/-0.028 molecules/100-eV) per mass of pore water was observed in the iron (III) oxide containing clay samples for hydrogen gas production. This value was noticeably larger when the samples were spiked with both KCl and KNO3 salts. The ratio of oxygen to nitrogen gas was observed to increase as a function of absorbed dose particularly in the presence of both KCI and KNO3 salts. The creation of radiolytic byproducts produced an observable but small increase in headspace pressure. Temperature increases during irradiation were not observed. Additionally, KCl and KNO3 salts added to the clays enhanced nitrite production as a function of radiation-dose and the type of clay considered. The addition of aluminum to these samples had no statistically discernable impact at the alpha = 0.05 level. Generation of the irradiation products, hydrogen peroxide and hydrogen gas also depended upon the type of clay irradiated and the presence of both KCI and KNO3 salts and the total dose received. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Idaho State Univ, Dept Phys, Pocatello, ID 83209 USA. Idaho State Univ, Dept Chem, Pocatello, ID 83209 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Brey, RR (reprint author), Idaho State Univ, Dept Phys, Campus Box 8106, Pocatello, ID 83209 USA. NR 10 TC 6 Z9 6 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0956-053X J9 WASTE MANAGE JI Waste Manage. PY 2001 VL 21 IS 6 BP 581 EP 588 DI 10.1016/S0956-053X(00)00106-9 PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 454MU UT WOS:000169977000010 PM 11478625 ER PT J AU Pennell, KD Costanza, J Kong, LJ Martin, CA Ramsburg, CA Taylor, TP AF Pennell, Kurt D. Costanza, Jed Kong, Lingjun Martin, Charlotte A. Ramsburg, C. Andrew Taylor, Tammy P. TI GROUNDWATER QUALITY SO WATER ENVIRONMENT RESEARCH LA English DT Article C1 [Pennell, Kurt D.; Costanza, Jed; Kong, Lingjun; Martin, Charlotte A.; Ramsburg, C. Andrew] Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. [Taylor, Tammy P.] Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Pennell, KD (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, 790 Atlantic Dr, Atlanta, GA 30332 USA. RI Pennell, Kurt/F-6862-2010; Ramsburg, Andrew/A-8532-2008 OI Pennell, Kurt/0000-0002-5788-6397; Ramsburg, Andrew/0000-0002-7138-6575 NR 631 TC 0 Z9 0 U1 2 U2 7 PU WATER ENVIRONMENT FEDERATION PI ALEXANDRIA PA 601 WYTHE ST, ALEXANDRIA, VA 22314-1994 USA SN 1061-4303 EI 1554-7531 J9 WATER ENVIRON RES JI Water Environ. Res. PY 2001 VL 73 IS 5 BP 1308 EP 1467 DI 10.2175/106143001X143772 PG 160 WC Engineering, Environmental; Environmental Sciences; Limnology; Water Resources SC Engineering; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA V19HR UT WOS:000208064000029 ER PT S AU Skubal, LR Vogt, MC Meshkov, NK AF Skubal, LR Vogt, MC Meshkov, NK BE VoDinh, T Spellicy, RL TI Monitoring the electrical response of photoinduced organic oxidation on TiO2 surfaces SO WATER, GROUND, AND AIR POLLUTION MONITORING AND REMEDIATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Water, Ground, and Air Pollution Monitoring and Remediation CY NOV 06-07, 2000 CL BOSTON, MA SP SPIE DE titanium dioxide; sensor; gaseous; oxidation ID HETEROGENEOUS PHOTOCATALYTIC OXIDATION; TITANIUM-DIOXIDE; THIN-FILM; DEGRADATION; TRICHLOROETHYLENE; GAS; AIR; PHOTORESPONSE; SENSOR AB Gaseous photo-induced oxidations of a variety of organic compounds by titanium dioxide (TiO2) have been studied extensively in the literature. The response of the organic to photochemical reactions with TiO2 and the extent of organic oxidation are typically measured by monitoring the initial concentration of organic and the oxidation by-products using gas chromatography. In this study, TiO2 sensors are produced by coating and drying films of Degussa P25 TiO2 onto Al2O3 substrates. Tests are conducted at ambient temperatures in a controlled atmospheric cell. Electrical responses from the TiO2 sensors are monitored as the sensors are exposed to a variety of organic compounds in the presence of ultraviolet light. Unique voltammetric "signatures" are obtained from the sensors as they react with specific gaseous organics. These signatures can be used to distinguish and identify gaseous constituents. C1 Argonne Natl Lab, Div Energy Syst, Argonne, IL 60439 USA. RP Skubal, LR (reprint author), Argonne Natl Lab, Div Energy Syst, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 21 TC 0 Z9 0 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3864-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4199 BP 157 EP 164 DI 10.1117/12.417376 PG 8 WC Engineering, Environmental; Optics SC Engineering; Optics GA BS25U UT WOS:000169199800018 ER PT S AU Cullum, BM Mobley, J Bogard, JS Moscovitch, M Phillips, GW Vo-Dinh, T AF Cullum, BM Mobley, J Bogard, JS Moscovitch, M Phillips, GW Vo-Dinh, T BE VoDinh, T Spellicy, RL TI Detection of neutrons using a novel three-dimensional optical random access memory technology (3D-ORAM) SO WATER, GROUND, AND AIR POLLUTION MONITORING AND REMEDIATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Water, Ground, and Air Pollution Monitoring and Remediation CY NOV 06-07, 2000 CL BOSTON, MA SP SPIE DE neutron dosimeter; optical memory; 3D-ORAM; dosimeter; neutron; two-photon; multiphoton excitation ID 2-PHOTON MEMORY; STORAGE MEMORY AB We report for the first time, the development of a three-dimensional optical random access memory (3D-ORAM) material for neutron dosimetry. Detection of energetic neutrons is important in many applications, spanning from radioactive waste monitoring to space exploration. These anthracene-based photochromic dosimeters show a decrease in fluorescence intensity following exposure to energetic neutrons. Unlike current neutron dosimeters, where foreknowledge of the neutron energy is necessary to determine an exposure dose, these materials can be used in unknown environments (e.g. space exploration). A readout system has also been developed to determine the radiation characteristics (e.g. neutron energy) necessary for estimating dose. The results presented in this work, demonstrate the potential of these novel materials for space exploration and other applications where foreknowledge of neutron energy is unknown and current dosimeters are incapable of providing accurate dose information. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Bethel Valley Rd,MS 6101,POB 2008, Oak Ridge, TN 37831 USA. NR 14 TC 0 Z9 0 U1 1 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3864-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4199 BP 165 EP 172 DI 10.1117/12.417372 PG 8 WC Engineering, Environmental; Optics SC Engineering; Optics GA BS25U UT WOS:000169199800019 ER PT S AU Chi, ZH Cullum, BM Mobley, J Miller, GH Vo-Dinh, T AF Chi, ZH Cullum, BM Mobley, J Miller, GH Vo-Dinh, T BE VoDinh, T Spellicy, RL TI Vapor detection of polyaromatic compounds using laser-induced fluorescence SO WATER, GROUND, AND AIR POLLUTION MONITORING AND REMEDIATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on Water, Ground, and Air Pollution Monitoring and Remediation CY NOV 06-07, 2000 CL BOSTON, MA SP SPIE DE laser-induced fluorescence; PAHs; high temperature; vapor; pyrene; anthracene ID POLYCYCLIC AROMATIC-HYDROCARBONS; TEMPERATURES; MECHANISMS; SPECTRA; FLAMES; PYRENE AB In this work, we present the fluorescence spectra of anthracene and pyrene vapors at different elevated temperatures (from 150 to 650 degreesC) excited with the 337 nm line of a nitrogen laser. We describe the high temperature effects on the resulting spectral properties including spectral intensity, spectral bandwidth and spectral shift. We found that the PAH fluorescence spectral bandwidths become very broad as the temperature increases. The broadening is mainly due to thermal vibrational sequence congestion. We also have found that the fluorescence intensity of pyrene vapor increases with increasing temperature, which results from the increase of the pyrene vapor absorption cross section at 337 nm. C1 Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. NR 20 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3864-2 J9 P SOC PHOTO-OPT INS PY 2001 VL 4199 BP 173 EP 179 DI 10.1117/12.417374 PG 7 WC Engineering, Environmental; Optics SC Engineering; Optics GA BS25U UT WOS:000169199800020 ER PT J AU O'Loughlin, E Chin, YP AF O'Loughlin, E Chin, YP TI Effect of detector wavelength on the determination of the molecular weight of humic substances by high-pressure size exclusion chromatography SO WATER RESEARCH LA English DT Article DE humic; fulvic; HPSEC; molecular weight; polydispersity ID DISSOLVED ORGANIC-MATTER; SPECTROSCOPIC PROPERTIES; ACTIVATED CARBON; PERFORMANCE; ADSORPTION; WATERS AB High-pressure size exclusion chromatography (HPSEC) has proven to be an effective method for determining the molecular weights (MW) of humic substances (HS) from a variety of aquatic and terrestrial environments. HPSEC systems often use a variable wavelength UV-vis detector, which detects the analytes based upon their chromophoric composition. HS contain a range of moieties with chromophores having unique molar absorptivities (for a given wavelength), and the calculated MW may be dependent upon the wavelength chosen for the analysis. As a consequence, the choice of wavelength becomes an important parameter for the reliable determination of MW by HPSEC. The effect of UV-vis detector wavelength on the determination of the MW distribution of selected humic and fulvic acids by HPSEC is examined in this paper. For the HS examined, both the number (M-n) and weight average (M-w) MW increased with increasing wavelength. The relative increase in MW was most pronounced for Lake Fryxell fulvic acid, with a 63 and 21% increase in M-n and M-w, respectively, between 220 and 380 nm. The increases observed for Suwannee River humic and fulvic acids were less pronounced, M-n was more sensitive to changes in detector wavelength than M-w, and as a result the target HS appeared to be less polydisperse at higher wavelengths. Within the range of wavelengths commonly used for the determination of MW of HS by HPSEC (i.e., 220-280 nm), the magnitude of the increases in MW was not significant compared to variability in MW that results from changes to other operational parameters in HPSEC. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Ohio State Univ, Environm Sci Program, Columbus, OH 43210 USA. Ohio State Univ, Dept Geol Sci, Columbus, OH 43210 USA. RP O'Loughlin, E (reprint author), Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. NR 21 TC 70 Z9 70 U1 1 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0043-1354 J9 WATER RES JI Water Res. PD JAN PY 2001 VL 35 IS 1 BP 333 EP 338 DI 10.1016/S0043-1354(00)00228-1 PG 6 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 381UN UT WOS:000165782000036 PM 11257891 ER PT J AU Durham, WB Bourcier, WL Burton, EA AF Durham, WB Bourcier, WL Burton, EA TI Direct observation of reactive flow in a single fracture SO WATER RESOURCES RESEARCH LA English DT Article ID FLUID-FLOW; SELF-ORGANIZATION; ROCK FRACTURES; POROUS-MEDIUM; DISSOLUTION; LIMESTONE; APERTURE; JOINTS AB We carried out a laboratory experiment to examine the relationship between local rate of dissolution and local aperture during flow of a slightly acidic aqueous solution through a rough fracture in Carrara marble under a confining pressure of 0.2 MPa. Fracture surfaces were digitized in three dimensions before the fluid flow tests and after the tests.,Digital reconstruction of the aperture then allowed numerical simulation of flow patterns, and digital comparison of surfaces before and after dissolution allowed mapping of patterns of dissolution. We observed that bath mean aperture and fracture permeability decreased as a result of dissolution. Despite the low confining pressure, the experiments thus simulate dissolution in deeply buried formations, in contrast to the gaping and karst formation that occur under vanishingly low confining pressure in the shallow crust. We observed that the growth of new pathways for flow changed from stable to unstable as length scale increased. At the millimeter scale the fracture aperture evolved in stable fashion from a strongly heterogeneous arrangement of tortuous flow channels to a smoother topography, while at the scale of the full rock (50 mm), the aperture developed a single, broad flow channel. The scale dependence of the dissolution pattern may be the result of changes with scale in extent of reaction (i.e., the Damkohler number) and in the relative importance of diffusion (the Peclet number). Finally, we also see evidence of a negative relationship between local fluid flux and local rate of dissolution in some locations in the fracture. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Chevron Petr Technol Co, San Ramon, CA 94583 USA. RP Durham, WB (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 21 TC 62 Z9 65 U1 2 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 JAN PY 2001 VL 37 IS 1 BP 1 EP 12 DI 10.1029/2000WR900228 PG 12 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 390UM UT WOS:000166315300001 ER PT B AU Benezeth, P Palmer, DA Wesolowski, DJ Xiao, C Wood, SA AF Benezeth, P Palmer, DA Wesolowski, DJ Xiao, C Wood, SA BE Cidu, R TI Solubility and reaction rates of oxides and hydroxides to high temperatures with in situ pH measurement SO WATER-ROCK INTERACTION, VOLS 1 AND 2 LA English DT Proceedings Paper CT 10th International Symposium on Water-Rock Interaction CY JUL 10-15, 2001 CL VILLASIMIUS, ITALY SP Int Assoc Geochem & Cosmochem, Italian Natl Res Council, Univ Cagliari, Soc Geochim Italiana ID ALUMINUM SPECIATION; BOEHMITE SOLUBILITY; AQUEOUS-SOLUTION; EQUILIBRIA; GIBBSITE AB Summaries of experimental studies involving the equilibrium solubility of the crystalline solid phases boehmite (AlOOH), zincite (ZnO), and neodymium hydroxide (Nd(OH)(3)), and the dissolution/precipitation rates of aluminum solid phases (boehmite and gibbsite, Al(OH)3) are presented. These experiments were performed over a Aide range of pH (2-10), temperature (30 to 290 degreesC), and ionic strength (0.03-5.0), using a hydrogen-electrode concentration cell (HECC). This cell provides continuous, accurate in situ pH measurements of solid/solution mixtures to 295 degreesC. Some of the potentiometric investigations were complemented by batch (AlOOH and ZnO), and flow-through column (ZnO) experiments. This research represents the first studies ever reported of mineral solubility profiles across the entire pH range of natural waters, and their precipitation/dissolution rates at temperatures above 100 degreesC, involving direct pH monitoring. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. RI BENEZETH, Pascale/H-7969-2014 OI BENEZETH, Pascale/0000-0002-1841-2383 NR 18 TC 0 Z9 0 U1 0 U2 4 PU A A BALKEMA PUBLISHERS PI LEIDEN PA SCHIPHOLWEG 107C, PO BOX 447, 2316 XC LEIDEN, NETHERLANDS BN 90-2651-824-2 PY 2001 BP 235 EP 238 PG 4 WC Geochemistry & Geophysics; Environmental Sciences; Geology; Water Resources SC Geochemistry & Geophysics; Environmental Sciences & Ecology; Geology; Water Resources GA BT20E UT WOS:000172263500046 ER PT B AU Fenter, P Cheng, L Rihs, S Machesky, M Bedzyk, MJ Sturchio, NC AF Fenter, P Cheng, L Rihs, S Machesky, M Bedzyk, MJ Sturchio, NC BE Cidu, R TI Probing the electrical double-layer structure at the rutile-water interface with X-ray standing waves SO WATER-ROCK INTERACTION, VOLS 1 AND 2 LA English DT Proceedings Paper CT 10th International Symposium on Water-Rock Interaction CY JUL 10-15, 2001 CL VILLASIMIUS, ITALY SP Int Assoc Geochem & Cosmochem, Italian Natl Res Council, Univ Cagliari, Soc Geochim Italiana AB We demonstrate that the X-ray standing wave (XSW) technique is a powerful probe of the electrical double-layer (EDL) structure. Measurements were made of Sr adsorption at the rutile (110)-water interface from aqueous solutions. Our results show that Bragg XSW, using small-period standing waves generated by Bragg diffraction from the substrate, precisely probes the location of ions within the condensed layer, and the in situ partitioning of ions between the condensed and diffuse layers. Such measurements can provide important constraints for the development and verification of theoretical models that describe ion adsorption at the solid-water interface. C1 Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Environm Res, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Bedzyk, Michael/B-7503-2009; Cheng, Likwan/C-1436-2013; Bedzyk, Michael/K-6903-2013 NR 9 TC 0 Z9 0 U1 0 U2 1 PU A A BALKEMA PUBLISHERS PI LEIDEN PA SCHIPHOLWEG 107C, PO BOX 447, 2316 XC LEIDEN, NETHERLANDS BN 90-2651-824-2 PY 2001 BP 263 EP 266 PG 4 WC Geochemistry & Geophysics; Environmental Sciences; Geology; Water Resources SC Geochemistry & Geophysics; Environmental Sciences & Ecology; Geology; Water Resources GA BT20E UT WOS:000172263500053 ER PT J AU Ghosh, S Jerger, D Henry, MP Sajjad, A AF Ghosh, S Jerger, D Henry, MP Sajjad, A TI Rapid-rate thermophilic, single-stage and two-phase methane fermentation of synfuel-industry wastewaters SO WATER SCIENCE AND TECHNOLOGY LA English DT Article; Proceedings Paper CT 1st World Water Congress of the International-Water-Association (IWA) CY JUL 03-07, 2000 CL PARIS, FRANCE SP Int Water Assoc DE anaerobic; rapid-rate; thermophilic; peat; wet-carbonization waste; upflow; single-stage; two phase; fixed film AB Thermophilic (55 degreesC) anaerobic digestion of wastewaters from wet carbonization of Minnesota peat was conducted in a simple, upflow digester at an HRT of one day to provide a methane yield of 0.20 SCM/kg VS added and a BOD5 reduction of 85%. Carbonization of Maine peat conducted for a much longer duration of thermal treatment produced recalcitrant and potentially toxic end products that reduced the biodegradability of wastewaters. Methane fermentation of the Maine-peat wet-carbonization waste was inhibited at an HRT of one day in the single-stage digester. However, two-phase digestion with separate acid-phase fermentation to promote hydrolytic degradation of toxic end products followed by separate methane fermentation at an HRT of 2 days exhibited a methane yield of 0.21 SCM/kg VS added and a BOD5 reduction of 76 %. Volatile fatty acids profiles along the depths digesting cultures indicated that single-stage and two-phase digestion could be accomplished at one-half the reactor residence times tone day for single-stage and three days far two-phase) used in this research. C1 Univ Utah, Dept Civil & Environm Engn, Salt Lake City, UT 84112 USA. Argonne Natl Lab, Argonne, IL 60439 USA. US EPA, Chicago, IL USA. RP Ghosh, S (reprint author), Univ Utah, Dept Civil & Environm Engn, Salt Lake City, UT 84112 USA. NR 13 TC 0 Z9 1 U1 0 U2 1 PU I W A PUBLISHING PI LONDON PA ALLIANCE HOUSE, 12 CAXTON ST, LONDON SW1H0QS, ENGLAND SN 0273-1223 J9 WATER SCI TECHNOL JI Water Sci. Technol. PY 2001 VL 43 IS 1 BP 35 EP 42 PG 8 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 408FX UT WOS:000167316800005 PM 11379110 ER PT J AU Whiteman, CD Zhong, S Shaw, WJ Hubbe, JM Bian, X Mittelstadt, J AF Whiteman, CD Zhong, S Shaw, WJ Hubbe, JM Bian, X Mittelstadt, J TI Cold pools in the Columbia basin SO WEATHER AND FORECASTING LA English DT Article ID BOUNDARY-LAYER EVOLUTION; CANYONLAND BASIN; STABLE LAYERS; HEAT BUDGETS AB Persistent midwinter cold air pools produce multiday periods of cold, dreary weather in basins and valleys. Persistent stable stratification leads to the buildup of pollutants and moisture in the pool. Because the pool sometimes has temperatures below freezing while the air above is warmer, freezing precipitation often occurs, with consequent effects on transportation and safety. Forecasting the buildup and breakdown of these cold pools is difficult because the interacting physical mechanisms leading to their formation, maintenance, and destruction have received little study. In this paper, persistent wintertime cold pools in the Columbia River basin of eastern Washington are studied. First a succinct meteorological definition of a cold pool is provided and then a 10-yr database is used to develop a cold pool climatology. This is followed by a detailed examination of two cold pool episodes that were accompanied by fog and stratus using remote and in situ temperature and wind sounding data. The two episodes illustrate many of the physical mechanisms that affect cold pool evolution. In one case, the cold pool was formed by warm air advection above the basin and was destroyed by downslope winds that descended into the southern edge of the basin and progressively displaced the cold air in the basin. In the second case, the cold pool began with a basin temperature inversion on a clear night and strengthened when warm air was advected above the basin by a westerly flow that descended from the Cascade Mountains. The cold pool was nearly destroyed one afternoon by cold air advection aloft and by the growth of a convective boundary layer (CBL) following the partial breakup of the basin stratus. The cold pool restrengthened, however, with nighttime cooling and was destroyed the next afternoon by a growing CBL. C1 Pacific NW Natl Lab, Richland, WA USA. NOAA, NWS, Forecast Off, Pendleton, OR USA. RP Whiteman, CD (reprint author), Battelle NW Lab, POB 999, Richland, WA 99352 USA. NR 24 TC 72 Z9 72 U1 1 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PY 2001 VL 16 IS 4 BP 432 EP 447 DI 10.1175/1520-0434(2001)016<0432:CPITCB>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 459UZ UT WOS:000170271000004 ER PT J AU Nawrocki, JG Dupont, JN Robino, CV Marder, AR AF Nawrocki, JG Dupont, JN Robino, CV Marder, AR TI The stres-relief cracking susceptibility of a new ferritic steel - part 2: Multiple-pass heat-affected zone Simulations SO WELDING JOURNAL LA English DT Article DE stress relief; multipass welds; cracking susceptibility; PWHT; CGHAZ; heat-affected zone; temper bead; ferritic steel ID CARBIDES AB The stress-relief cracking susceptibility of multiple-pass welds in HCM2S, a new ferritic steel, and standard 2.25Cr-1Mo steel has been evaluated and compared to single-pass weld results using Gleeble techniques. Simulated coarse-grained heat-affected zones (CGHAZ) were produced using two- and three-pass thermal cycle simulations and tested at various postweld heat treatment (PWHT) temperatures. Light optical and scanning electron microscopy were used to characterize the CGHAZ microstructures. The multipass samples of each material failed along grain boundaries (prior austenite or packet) normal to the tensile axis and exhibited extensive plastic deformation, indicating that stress-relief cracking was avoided with the use of multipass simulations. The times to failure, when considering CGHAZ simulations, were longer than those of the single-pass samples at each PWHT temperature. The ductility increased with increasing PWHT temperature for each alloy and increased relative to the single-pass samples ateach PWHT temperature. The differences in stress-relief cracking response between the single- and multiple-pass samples are discussed in terms of the microstructural changes that take place during the multiple-pass procedure and subsequent PWHT. C1 Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 USA. Sandia Natl Labs, Dept Mat Joining, Albuquerque, NM 87185 USA. RP Nawrocki, JG (reprint author), Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 USA. NR 14 TC 0 Z9 0 U1 1 U2 2 PU AMER WELDING SOC PI MIAMI PA 550 N W LEJEUNE RD, MIAMI, FL 33126 USA SN 0043-2296 J9 WELD J JI Weld. J. PD JAN PY 2001 VL 80 IS 1 BP 18S EP 24S PG 7 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 746KG UT WOS:000186745100018 ER PT J AU Krumke, SO Marathe, MV Ravi, SS AF Krumke, SO Marathe, MV Ravi, SS TI Models and approximation algorithms for channel assignment in radio networks SO WIRELESS NETWORKS LA English DT Article; Proceedings Paper CT 3rd International Workshop on Discrete Algorithms and Methods for Mobile Computing and Communications CY 1999 CL SEATTLE, WA DE channel assignment; radio networks; approximation algorithms; geometric graphs ID UNIT DISK GRAPHS; HARD PROBLEMS AB We consider the frequency assignment (broadcast scheduling) problem for packet radio networks. Such networks are naturally modeled by graphs with a certain geometric structure. The problem of broadcast scheduling can be cast as a variant of the vertex coloring problem (called the distance-2 coloring problem) on the graph that models a given packet radio network, We present efficient approximation algorithms for the distance-2 coloring problem for various geometric graphs including those that naturally model a large class of packet radio networks. The class of graphs considered include (r, s)-civilized graphs, planar graphs, graphs with bounded genus, etc. C1 Konrad Zuse Zentrum Informat Tech Berlin, D-14195 Berlin, Germany. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. SUNY Albany, Dept Comp Sci, Albany, NY 12222 USA. RP Krumke, SO (reprint author), Konrad Zuse Zentrum Informat Tech Berlin, Takustr 7, D-14195 Berlin, Germany. EM krumke@zib.de; marathe@lanl.gov; ravi@cs.albany.edu NR 33 TC 73 Z9 73 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1022-0038 J9 WIREL NETW JI Wirel. Netw. PY 2001 VL 7 IS 6 BP 575 EP 584 DI 10.1023/A:1012311216333 PG 10 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 498XK UT WOS:000172538700003 ER PT B AU Wilson, JR AF Wilson, JR BE Shen, S TI How fast is the conveyor? SO WORLD RESOURCE REVIEW, VOL 13, NOS 2-4: GLOBAL WARMING SCIENCE & POLICY, PTS 1-3 SE GLOBAL WARMING INTERNATIONAL CENTER MONOGRAPH SERIES LA English DT Proceedings Paper CT 12th International Conference on Global Warming Science and Policy CY APR 08-11, 2001 CL UNIV CAMBRIDGE, CAMBRIDGE, ENGLAND HO UNIV CAMBRIDGE DE climate prediction; worldwide ocean Conveyor; carbon sequestration; missing sink; multidecadal cycles ID ATMOSPHERIC CO2; EL-NINO; SOUTHERN OSCILLATION; EQUATORIAL PACIFIC; MONSOON RAINFALL; RED-SEA; RADIOCARBON; THERMOSTAT; SIMULATION; ATLANTIC C1 Bechtel BWXT Idaho LLC, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Wilson, JR (reprint author), Bechtel BWXT Idaho LLC, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 49 TC 0 Z9 0 U1 0 U2 0 PU SUPCON INTERNATIONAL PI WOODRIDGE PA PO BOX 5275, WOODRIDGE, IL 60517-0275 USA J9 GLOB WARM INT CTR M PY 2001 BP 199 EP 220 PG 22 WC Environmental Sciences SC Environmental Sciences & Ecology GA BX57U UT WOS:000185752800003 ER PT B AU Dudenhoeffer, DD Bruemmer, DJ Davis, ML AF Dudenhoeffer, DD Bruemmer, DJ Davis, ML BE Peters, BA Smith, JS Medeiros, DJ Rohrer, MW TI Modeling and simulation for exploring human-robot team interaction requirements SO WSC'01: PROCEEDINGS OF THE 2001 WINTER SIMULATION CONFERENCE, VOLS 1 AND 2 LA English DT Proceedings Paper CT Winter Simulation Conference (WSC 01) CY 2001 CL ARLINGTON, VA SP Amer Stat Assoc, ACM SIGSIM, IEEE Comp Soc, IEEE Syst, Man & Cybernet Soc, Inst Ind Engineers, INFORMS Coll Simulat, Natl Inst Stand & Technol, Soc Comp Simulat Int AB Small-sized and micro-robots will soon be available for deployment in large-scale forces. Consequently, the ability of a human operator to coordinate and interact with largescale robotic forces is of great interest. This paper describes the ways in which modeling and simulation have been used to explore new possibilities for human-robot interaction. The paper also discusses how these explorations have fed implementation of a unified set of command and control concepts for robotic force deployment. Modeling and simulation can play a major role in fielding robot teams in actual missions. While live testing is preferred, limitations in terms of technology, cost, and time often prohibit extensive experimentation with physical multi-robot systems. Simulation provides insight, focuses efforts, eliminates large areas of the possible solution space, and increases the quality of actual testing. C1 Idaho Natl Lab, Human Syst Simulat Lab, Idaho Falls, ID 83415 USA. RP Dudenhoeffer, DD (reprint author), Idaho Natl Lab, Human Syst Simulat Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 15 TC 5 Z9 5 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-7307-3 PY 2001 BP 730 EP 739 DI 10.1109/WSC.2001.977361 PG 10 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA BV20W UT WOS:000178162700095 ER PT S AU Madejski, G Done, C Zycki, P AF Madejski, G Done, C Zycki, P BE Czerny, B TI Recent results for AGN observed by the Rossi X-ray timing explorer SO X-RAY AND GAMMA-RAY SIGNATURES OF BLACK HOLES AND WEAKLY MAGNETIZED NEUTRON STARS SE ADVANCES IN SPACE RESEARCH LA English DT Article; Proceedings Paper CT E1 2/H0 3 Symposium of COSPAR Scientific Commission E held at the 33rd COSPAR Scientific Assembly CY JUL, 2000 CL WARSAW, POLAND SP Danish ID ACTIVE GALACTIC NUCLEI; EMISSION; NGC-4945; GALAXIES AB The Rossi X-ray Timing Explorer (RXTE) has produced many excellent observations of active galaxies, providing so far the best sensitivity over the bandpass of 10 - 20 keV. This paper reports selected RTXE data for X-ray bright Seyfert galaxies in the context of the currently popular models. One is the recent result for two Seyfert I galaxies, NGC 5548 and IC 4329a: both show the "canonical" Seyfert I X-ray spectra, with an underlying power law, plus iron K alpha fluorescence line and Compton reflection. Interestingly, in both cases, the profile of the Fe K line does not extend as far to the red as seen in the famous MCG-6-30-15, and this indicates that the regions where the Fe K lines originate in AGN are diverse. Independently, in both objects we see a strong spectral variability of the primary continua, which soften as the sources brighten. The second result is for the heavily absorbed Seyfert 2 NGC 4945. The RXTE data confirm the strong absorption corresponding to the optical depth to electron scattering of about 2, but also reveal rapid variability of the hard (8 - 30 keV) X-ray emission on a time scale of a day or less. This suggests that for NGC 4945, the putative parsec-size molecular torus cannot be both geometrically and optically thick. It also implies that if the Cosmic X-ray Background is made up of heavily absorbed sources, they are unlikely to have the absorber confined to a geometrically thin disk as inferred for NGC 4945. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved. C1 Stanford Linear Accelerator Ctr, Menlo Pk, CA 94025 USA. Univ Durham, Dept Phys, Durham, England. Copernicus Astron Ctr, Warsaw, Poland. RP Madejski, G (reprint author), Stanford Linear Accelerator Ctr, Menlo Pk, CA 94025 USA. RI done, chris/D-4605-2016 OI done, chris/0000-0002-1065-7239 NR 18 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA SARA BURGERHARTSTRAAT 25, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0273-1177 J9 ADV SPACE RES PY 2001 VL 28 IS 2-3 BP 369 EP 373 DI 10.1016/S0273-1177(01)00434-3 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Engineering; Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA BT45X UT WOS:000173048700012 ER PT S AU Arthur, J Tatchyn, R AF Arthur, J Tatchyn, R BE Mills, DM SchulteSchrepping, H Arthur, JR TI Radiation properties of the Linac Coherent Light Source: Challenges for x-ray optics SO X-RAY FEL OPTICS AND INSTRUMENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray FEL Optics and Instrumentation CY JUL 30-31, 2000 CL SAN DIEGO, CA SP SPIE AB The Linac Coherent Light Source (LCLS) is a free-electron laser (FEL) now in the advanced planning stage at the Stanford Linear Accelerator Center. This machine will employ the process of self-amplified spontaneous emission (SASE) to generate extremely bright pulses of hard x-ray radiation, at wavelengths down to about 1.5A. Being the first laser to operate in this spectral region, it will produce radiation with properties that are radically different in several respects from that produced by any other x-ray source, including today's 3(rd)-generation synchrotron sources. Using this radiation to best scientific advantage will place unprecedented demands on the x-ray optics. Most importantly, the LCLS will be a pulsed radiation source, with extremely intense, short pulses and a low duty cycle. It will be possible and desirable to collect a complete experimental data set with a single radiation pulse. This will require optics which manipulate a single pulse so as to cover the full range of parameter space to be studied. Also, because of the very high peak power, sub-picosecond pulse length, and very high coherence of the FEL pulse, optics must be robust, able to preserve the short pulse length, and able to preserve spatial coherence. Finally, since it seems likely that the LCLS FEL radiation will be bright enough to promote nonlinear x-ray processes, there will be a need for optics which emphasize particular nonlinear effects. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Arthur, J (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NR 11 TC 5 Z9 5 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3788-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4143 BP 1 EP 8 DI 10.1117/12.413677 PG 8 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BS06U UT WOS:000168537600001 ER PT S AU McPherson, A AF McPherson, A BE Mills, DM SchulteSchrepping, H Arthur, JR TI The x-ray FEL: An experimenter's dilemma SO X-RAY FEL OPTICS AND INSTRUMENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray FEL Optics and Instrumentation CY JUL 30-31, 2000 CL SAN DIEGO, CA SP SPIE DE x-ray; FEL; synchronization; radiation damage; electromagnetic pulse AB The specifications of presently proposed x-ray free electron lasers (FELs) are for machines that will provide x-ray pulses as short as 100 fs with a photon energy as high as 12.3 keV. Since the pulse will contain as much as 13 mJ of energy, these devices will present the experimenter with an opportunity to expose matter to an unprecedented x-ray energy density. This high concentration of energetic x-rays presents both a promising frontier in energy-matter interaction, as well as a technological crevasse to be crossed by the experimenter attempting to use the FEL beam. We shall look at three possible problems confronting the experimenter: (1) synchronization of a detector, laser pulse, etc., to the FEL pulse; (2) radiation damage to the target sample; and (3) the presence of an electromagnetic pulse that could damage sensitive electronics located in the experimental area. C1 Argonne Natl Lab, UPD 401, Argonne, IL 60439 USA. RP McPherson, A (reprint author), Argonne Natl Lab, UPD 401, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3788-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4143 BP 20 EP 25 DI 10.1117/12.413689 PG 6 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BS06U UT WOS:000168537600004 ER PT S AU Shastri, SD Zambianchi, P Mills, DM AF Shastri, SD Zambianchi, P Mills, DM BE Mills, DM SchulteSchrepping, H Arthur, JR TI Femtosecond x-ray dynamical diffraction by perfect crystals SO X-RAY FEL OPTICS AND INSTRUMENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray FEL Optics and Instrumentation CY JUL 30-31, 2000 CL SAN DIEGO, CA SP SPIE DE x-ray free-electron lasers; x-ray optics; dynamical diffraction ID PULSES AB X-ray free-electron lasers (XFELs) designed to operate at similar to 1 Angstrom wavelengths are currently being proposed by several laboratories as the basis for the next (4th) generation of synchrotron radiation sources. The unique radiation properties of these proposed sources, which include 200 fs pulse duration and peak beam brilliance in excess of 10(33) photon/(s .1%-bw mrad(2) mm(2)), Offer the possibility of ultrafast time-resolved experiments, perhaps down to 10 fs resolution levels using pulse compression or slicing techniques. Motivated by such potential applications, this paper addresses the relevant instrumentation issue of perfect crystal dynamical diffraction of ultrashort x-ray pulses when the pulse lengths become comparable to the extinction length scales. The basic calculations reported here show the transient time-dependent diffraction from perfect crystals excited by plane-wave delta-function electromagnetic impulses. Time responses have been calculated for 8 keV photon energy, for reflected and transmitted beams in both Bragg and Laue cases. Interesting diffraction effects arise, and their implications for XFEL optics are discussed. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Shastri, SD (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 8 TC 12 Z9 13 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3788-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4143 BP 69 EP 77 DI 10.1117/12.413681 PG 9 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BS06U UT WOS:000168537600009 ER PT S AU Tatchyn, R Bionta, R AF Tatchyn, R Bionta, R BE Mills, DM SchulteSchrepping, H Arthur, JR TI Performance studies of a multilayer-based radiation pulse slicer for Linac Coherent Light Source (LCLS) applications SO X-RAY FEL OPTICS AND INSTRUMENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray FEL Optics and Instrumentation CY JUL 30-31, 2000 CL SAN DIEGO, CA SP SPIE DE Free-Electron Laser (FEL); X-Ray Free-Electron Laser (XRFEL); Self-Amplified Spontaneous Emission (SASE); Linac Coherent Light Source (LCLS); temporal compression; time slicing; Fourier transform; multilayer; phase space; Bragg condition; impulse response; convolution AB The SLAG Linac Coherent Light Source (LCLS), an X-ray Free-Electron Laser (XRFEL) designed to operate over a fundamental energy range of 1 - 8.5 keV, is expected to produce ultra-short pulse lengths down to similar to 200 fs. Even though this represents an enormous decrease with respect to currently available high-brightness X-ray sources, it is believed that for a number of proposed LCLS applications (e.g., imaging or structural studies of molecular clusters with highly focused pulses) it will become necessary to reduce the pulse duration even further, possibly by as much as 1-2 orders of magnitude. Of the various compressive or chopping (i.e., slicing) optical techniques considered for shortening the pulse, the focus of one of our recent studies has been on a recently proposed slicing scheme based on the interaction of a longitudinally chirped LCLS pulse with a specially designed multilayer. The chopping mechanism is the selective reflection of only that sub-interval of the pulse that fulfills the multilayer Bragg condition. Of particular interest are the reflection efficiency and the distortion induced in the temporal fine structure of the reflected pulse, both of which can be critical to the efficacy of the scheme for a given application. Here we present results of selected parameter studies of different multilayer-based beam chopper systems using codes and LCLS radiation models developed at SSRL and LLNL. C1 Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. RP Tatchyn, R (reprint author), Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. NR 22 TC 7 Z9 7 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3788-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4143 BP 89 EP 97 DI 10.1117/12.413683 PG 9 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BS06U UT WOS:000168537600011 ER PT S AU Assoufid, L AF Assoufid, L BE Mills, DM SchulteSchrepping, H Arthur, JR TI Future metrology needs for FEL reflective optics SO X-RAY FEL OPTICS AND INSTRUMENTATION SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray FEL Optics and Instrumentation CY JUL 30-31, 2000 CL SAN DIEGO, CA SP SPIE DE pptical metrology; free-electron laser; grazing-incidence mirror; surface figure; surface finish AB An International Workshop on Metrology for X-ray and Neutron Optics has been held March 16-17, 2000, at the Advanced Photon Source, Argonne National Laboratory near Chicago, Illinois (USA). The workshop gathered engineers and scientists from both the U.S. and around the world to evaluate metrology instrumentation and methods used to characterize surface figure and finish for long grazing incidence optics used in beamlines at synchrotron radiation sources. This two-day workshop was motivated by the rapid evolution in the performance of x-ray and neutron sources along with requirements in optics figure and finish. More specifically, the performance of future light sources, such as free-electron laser (FEL)-based x-ray sources, is being pushed to new limits in term of both brilliance and coherence. As a consequence, tolerances on surface figure and finish of the next generation of optics are expected to become tighter. The timing of the workshop provided an excellent opportunity to study the problem, evaluate the state of the art in metrology instrumentation, and stimulate innovation on future metrology instruments and techniques to be used to characterize these optics. This paper focuses on FEL optics and metrology needs. (A more comprehensive summary of the workshop can be found elsewhere.(1)) The performance and limitations of current metrology instrumentation will be discussed and recommendations from the workshop on future metrology development to meet the FEL challenges will be detailed. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Assoufid, L (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-3788-3 J9 P SOC PHOTO-OPT INS PY 2001 VL 4143 BP 98 EP 102 DI 10.1117/12.413685 PG 5 WC Instruments & Instrumentation; Optics SC Instruments & Instrumentation; Optics GA BS06U UT WOS:000168537600012 ER PT S AU Lang, JC Pollmann, J Haskel, D Srajer, G Maser, J Jiang, JS Bader, SD AF Lang, JC Pollmann, J Haskel, D Srajer, G Maser, J Jiang, JS Bader, SD BE McNulty, I TI Imaging buried magnetic domains using hard x-rays SO X-RAY MICRO- AND NANO-FOCUSING: APPLICATIONS AND TECHNIQUES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Micro- and Nano-Focusing - Applications and Techniques II CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE imaging; magnetism; x-ray optics; synchrotron radiation ID SPRING MAGNET; EXCHANGE; FILMS; ANISOTROPY; MICROSCOPY; BILAYERS; PLATES AB Images of magnetic structures in a SmCo/Fe bilayer have been obtained using a circularly polarized hard x-ray microprobe. This probe combines circularly polarizing and microfocusing optics (either Fresnel zone plate or Kirkpatrick-Baez mirrors) to provide a highly polarized, small cross-section x-ray beam in the energy range between 5 and 12 keV. By using x-rays in this energy range, we can penetrate the top layers of the sample and therefore are able to measure the magnetic domains of buried magnetic structures with a resolution of similar to5 lam. Contrast between magnetic domains is obtained by measuring the x-ray magnetic circular dichroism signal for different points as the beam is scanned across the sample. Images of the magnetic domain structure in a 1600-Angstrom-thick buried SmCo layer of a SmCo/Fe bilayer were taken as a function of the externally applied magnetic field. These images show the nucleation of large domains ( 100 mum) whose domain walls are oriented perpendicular to the applied field direction. Upon increasing the applied field, the images show the growth of the local reversed domains as the domain walls propagate across the sample, leading to a complete reorientation of the hard magnetic layer. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Lang, JC (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RI Maser, Jorg/K-6817-2013 NR 26 TC 4 Z9 4 U1 0 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4213-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4499 BP 1 EP 9 DI 10.1117/12.450228 PG 9 WC Microscopy; Optics; Imaging Science & Photographic Technology SC Microscopy; Optics; Imaging Science & Photographic Technology GA BU13P UT WOS:000175126400001 ER PT S AU Cai, Z Lai, B Ilinski, P Legnini, D Yun, W AF Cai, Z Lai, B Ilinski, P Legnini, D Yun, W BE McNulty, I TI X-ray microdiffraction study of martensite-retained austenite microstructures at the tip of a steel blade SO X-RAY MICRO- AND NANO-FOCUSING: APPLICATIONS AND TECHNIQUES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Micro- and Nano-Focusing - Applications and Techniques II CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE AB The x-ray microdiffraction technique was used to study lattice-strain field and phase concentration near the surface of a carburised steel blade on a micron length scale. Our results show larger compressive lattice strains and more completed phase transformation at the location near the tip of the blade than that at the locations away from the tip. C1 Argonne Natl Lab, Expt Facil Div, Argonne, IL 60439 USA. RP Cai, Z (reprint author), Argonne Natl Lab, Expt Facil Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 7 TC 0 Z9 0 U1 1 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4213-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4499 BP 19 EP 22 DI 10.1117/12.450233 PG 4 WC Microscopy; Optics; Imaging Science & Photographic Technology SC Microscopy; Optics; Imaging Science & Photographic Technology GA BU13P UT WOS:000175126400003 ER PT S AU McNulty, I AF McNulty, I BE McNulty, I TI Current and ultimate limitations of scanning x-ray nanotomography SO X-RAY MICRO- AND NANO-FOCUSING: APPLICATIONS AND TECHNIQUES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Micro- and Nano-Focusing - Applications and Techniques II CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE scanning x-ray microscope; 3D imaging; nanotomography; tomography; nanometer ID INTEGRATED-CIRCUIT INTERCONNECT; RESOLUTION; TOMOGRAPHY; MICROSCOPE; MICROTOMOGRAPHY; PERFORMANCE AB X-ray nanotomography has developed into a powerful new tool for three-dimensional structural analysis. The scanning approach offers capabilities that are competitive with full-field imaging. Current and ultimate limitations of nanotomography are examined in light of recent work. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP McNulty, I (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 19 TC 2 Z9 2 U1 2 U2 4 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4213-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4499 BP 23 EP 28 DI 10.1117/12.450234 PG 6 WC Microscopy; Optics; Imaging Science & Photographic Technology SC Microscopy; Optics; Imaging Science & Photographic Technology GA BU13P UT WOS:000175126400004 ER PT S AU Chao, WL Anderson, EH Denbeaux, G Harteneck, B Pearson, AL Olynick, D Schneider, G Attwood, D AF Chao, WL Anderson, EH Denbeaux, G Harteneck, B Pearson, AL Olynick, D Schneider, G Attwood, D BE McNulty, I TI Experimental analysis of high-resolution soft x-ray microscopy SO X-RAY MICRO- AND NANO-FOCUSING: APPLICATIONS AND TECHNIQUES II SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT Conference on X-Ray Micro- and Nano-Focusing - Applications and Techniques II CY JUL 30, 2001 CL SAN DIEGO, CA SP SPIE DE soft x-ray microscope; XM-1; high aspect ratio; zone plate; resolution; gold island pattern ID TRANSMISSION AB The soft x-ray, full-field microscope XM-1 at Lawrence Berkeley National Laboratory's (LBNL) Advanced Light Source has already demonstrated its capability to resolve 25-nm features. This was accomplished using a micro zone plate (MZP) with an outer zone width of 25 run. Limited by the aspect ratio of the resist used in the fabrication, the goldplating thickness of that zone plate is around 40 nm. However, some applications, in particular, biological imaging, prefer improved efficiency, which can be achieved by high-aspect-ratio zone plates. We accomplish this by using a bilayer-resist process in the zone plate fabrication. As our first attempt, a 40-nm-outer-zone-width MZP with a nickelplating thickness of 150 nm (aspect ratio of 4: 1) was successfully fabricated. Relative to the 25-nm MZP, this zone plate is ten times more efficient. Using this high-efficiency MZP a line test pattern with half period of 30 rim is resolved by the microscope at photon energy of 500 eV. Furthermore, with a new multilayer mirror, the XM-1 can now perform imaging up to 1.8 keV. An image of a line test pattern with half period of 40 nm has a measured modulation of 90%. The image was taken at 1.77 keV with the high-efficiency MZP with an outer zone width of 35 nm and a nickel-plating thickness of 180 nm (aspect ratio of 5: 1). XM-1 provides a gateway to high-resolution imaging at high energy. To measure frequency response of the a partially annealed gold "island" pattern was chosen as a test object. After comparison with the SEM image of the pattern, the microscope has the measured cutoff of 19 nm, close to the theoretical one of 17 nm. The normalized frequency response, which is the ratio of the power density of the soft x-ray image to that of the SEM image, is shown in this paper. C1 Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. RP Chao, WL (reprint author), Lawrence Berkeley Natl Lab, Ctr Xray Opt, 1 Cyclotron Rd,MS 2-400, Berkeley, CA 94720 USA. NR 9 TC 1 Z9 1 U1 0 U2 1 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4213-5 J9 P SOC PHOTO-OPT INS PY 2001 VL 4499 BP 134 EP 141 DI 10.1117/12.450231 PG 8 WC Microscopy; Optics; Imaging Science & Photographic Technology SC Microscopy; Optics; Imaging Science & Photographic Technology GA BU13P UT WOS:000175126400016 ER PT S AU Assoufid, L Khounsary, A Qian, J Macrander, A Mills, D AF Assoufid, L Khounsary, A Qian, J Macrander, A Mills, D BE Freund, AK Ishikawa, T Khounsary, AM TI Surface quality of x-ray mirrors evaluated at the Advanced Photon Source SO X-RAY MIRRORS, CRYSTALS AND MULTILAYERS SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 2nd Conference on X-Ray Mirrors, Crystals and Multilayers CY JUL 30-31, 2001 CL SAN DIEGO, CA SP SPIE DE x-ray mirrors; surface figure; surface slope error; roughness; slope error; metrology; synchrotron radiation AB X-ray mirrors are polished and often coated optical substrates used on many synchrotron x-ray beamlines to reflect, focus, steer, or filter x-ray beams. Because their performance depends strongly on their surface quality, they are usually evaluated after delivery, independently (from the vendor), for compliance before acceptance by the buyer. This paper summarizes results of surface roughness and slope error measurements of mirrors delivered to the Advanced Photon Source (APS) and evaluated in the metrology laboratory during the period 1996 - 2001, using non-contact surface profilometry. For all the mirrors evaluated, the measured root-mean square (rms) slope error values range from 0.5 to 4.7 murad rms, and the surface rms values range from 0.9 to 4.3 A rms. Most of the measured mirrors have met the user specifications. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Assoufid, L (reprint author), Argonne Natl Lab, Adv Photon Source, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-4215-1 J9 P SOC PHOTO-OPT INS PY 2001 VL 4501 BP 54 EP 62 AR UNSP 4501-05 DI 10.1117/12.448498 PG 9 WC Optics SC Optics GA BU16B UT WOS:000175177300006 ER PT B AU Macintosh, B Max, C Zuckerman, B Becklin, EE Kaisler, D Lowrance, P Weinberger, A Christou, J Schneider, G Acton, S AF Macintosh, B Max, C Zuckerman, B Becklin, EE Kaisler, D Lowrance, P Weinberger, A Christou, J Schneider, G Acton, S BE Jayawardhana, R Greeme, TP TI Keck adaptive optics observations of TW hydrae association members SO YOUNG STARS NEAR EARTH: PROGRESS AND PROSPECTS SE ASTRONOMICAL SOCIETY OF THE PACIFIC CONFERENCE SERIES LA English DT Proceedings Paper CT Workshop on Young Stars Near Earth CY MAR 28-30, 2001 CL NASA AMES RES CTR, MT VIEW, CA SP NASA Off Space Sci HO NASA AMES RES CTR ID TELESCOPE; IMAGES AB Adaptive optics (AO) on 8-10 m telescopes is an enormously powerful tool for studying young nearby stars. It is especially useful for searching for companions. Using AO on the 10-m W.M H. Keck II telescope we have measured the position of the brown dwarf companion to TWA5 and resolved the primary into an 0.055" double. Over the next several years follow-up astrometry should permit an accurate determination of the masses of these young stars. We have also re-observed the candidate extrasolar planet TWAGB, but measurements of its motion relative to TWAGA are inconclusive. We are carrying out a search for new planetary or brown dwarf companions to TWA stars and, if current giant planet models are correct, are currently capable of detecting a 1 Jupiter-mass companion at similar to 1.0" and a 5 Jupiter-mass companion at similar to 0.5" around a typical TWA member. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Macintosh, B (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 7 TC 14 Z9 14 U1 0 U2 1 PU ASTRONOMICAL SOC PACIFIC PI SAN FRANCISCO PA 390 ASHTON AVE, SAN FRANCISCO, CA 94112 USA BN 1-58381-082-X J9 ASTR SOC P PY 2001 VL 244 BP 309 EP 315 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BU34B UT WOS:000175724200051 ER PT S AU Smither, R Ballmoos, PV Skinner, G AF Smither, R Ballmoos, PV Skinner, G CA Balloon Launch Crew BE Holt, SS Hwang, U TI A brief update on the first balloon flight of a crystal diffraction lens telescope, CLAIRE SO YOUNG SUPERNOVA REMNANTS SE AIP Conference Proceedings LA English DT Proceedings Paper CT 11th Annual Astrophysics Conference CY OCT 16-18, 2000 CL COLLEGE PK, MD AB The first balloon flight of a crystal diffraction lens telescope, CLAIRE, took place on June 15, 2000 from Gap, France. The target for the telescope was the Crab Nebula. This is the first time that a Laue (transmission) type crystal diffraction lens(1-2) has been used to look an astrophysics source. It is the first of three balloon flights planned to test this concept for future astrophysics experiments and the possibility of a satellite experiment. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. EM rks@aps.anl.gov NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-243X BN 0-7354-0001-6 J9 AIP CONF PROC PY 2001 VL 565 BP 317 EP 320 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA BS29B UT WOS:000169367800044 ER PT J AU Bryan, JC Mlinaric-Majerski, K Kragol, G Marchand, AP AF Bryan, JC Mlinaric-Majerski, K Kragol, G Marchand, AP TI Crystal structure of 1,3-bis(hydroxymethyl)-2-oxaadamantane, C11H18O3 SO ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES LA English DT Article AB C11H18O3, triclinic, P (1) over bar (No, 2), a = 6.295(2) Angstrom, b = 11.623(4) Angstrom, c = 14.141(3) Angstrom, alpha = 94.67(2)degrees, beta = 98.50(2)degrees, gamma = 99.29(3)degrees, V = 1004.0 Angstrom (3), Z = 4, R-gt(F)= 0.061, wR(ref)(F-2) = 0.177, T = 100 K. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Rudjer Boskovic Inst, Dept Organ Chem & Biochem, Zagreb 10002, Croatia. Univ N Texas, Dept Chem, Denton, TX 76203 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. EM bryanjc@ornl.gov NR 11 TC 0 Z9 0 U1 0 U2 1 PU OLDENBOURG VERLAG PI MUNICH PA LEKTORAT MINT, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY SN 1433-7266 J9 Z KRIST-NEW CRYST ST JI Z. Krist.-New Cryst. Struct. PY 2001 VL 216 IS 2 BP 277 EP 279 PG 3 WC Crystallography SC Crystallography GA 435DK UT WOS:000168862000051 ER PT J AU Jones, CY Bryan, JC Kirschbaum, K Edwards, JG AF Jones, CY Bryan, JC Kirschbaum, K Edwards, JG TI Refinement of the crystal structure of digallium trisulfide, Ga2S3 SO ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES LA English DT Article AB Ga2S3, monoclinic. C1c1 (No. 9). a = 11.107(2) Angstrom, b = 6.395(1) Angstrom, c = 7.021(1) Angstrom, beta = 121.17(3)degrees, V = 426.7 Angstrom (3), Z = 4, R-gt(F) = 0.035, wR(ref)(F-2) = 0.084, T = 294 K. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Univ Toledo, Dept Chem, Toledo, OH 43606 USA. RP Jones, CY (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 13 TC 5 Z9 5 U1 0 U2 7 PU R OLDENBOURG VERLAG PI MUNICH PA LEKTORAT M/N, K BERBER-NERLINGER, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY SN 1433-7266 J9 Z KRIST-NEW CRYST ST JI Z. Krist.-New Cryst. Struct. PY 2001 VL 216 IS 3 BP 327 EP 328 PG 2 WC Crystallography SC Crystallography GA 461XV UT WOS:000170389900004 ER PT J AU Bryan, JC Sachleben, RA AF Bryan, JC Sachleben, RA TI Crystal structure of 26,28-bis(2-propenyloxy)calix[4]arene, C34H32O4 SO ZEITSCHRIFT FUR KRISTALLOGRAPHIE-NEW CRYSTAL STRUCTURES LA English DT Article AB C34H32O4, monoclinic, P12(1)/c1 (No. 14), a = 15.698(2) Angstrom, b = 20.607(2) Angstrom, c = 17.446(2) Angstrom, beta = 110.682(7)degrees, V = 5279.9 Angstrom(3), Z = 8, R-gt(F) = 0.055, wR(ref)(F-2) = 0.162, T = 163 K. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Bryan, JC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU R OLDENBOURG VERLAG PI MUNICH PA LEKTORAT M/N, K BERBER-NERLINGER, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY SN 1433-7266 J9 Z KRIST-NEW CRYST ST JI Z. Krist.-New Cryst. Struct. PY 2001 VL 216 IS 4 BP 623 EP 625 PG 3 WC Crystallography SC Crystallography GA 563EX UT WOS:000176244100070 ER PT J AU Davis, MJ Skodje, RT AF Davis, MJ Skodje, RT TI Geometric approach to multiple-time-scale kinetics: A nonlinear master equation describing vibration-to-vibration relaxation SO ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS LA English DT Article DE nonlinear master equation; low-dimensional manifolds; vibrational relaxation; multiple-time-scale kinetics ID THERMAL UNIMOLECULAR REACTIONS; LOW-DIMENSIONAL MANIFOLDS; COLLISION RATE CONSTANTS; STEADY-STATE APPROXIMATION; FALL-OFF RANGE; REACTION-MECHANISMS; PREMIXED FLAMES; ENERGY-TRANSFER; LOW-PRESSURES; SYSTEMS AB A geometric approach to the study of multiple-time-scale kinetics is taken here. The approach to equilibrium for kinetic systems is studied via low-dimensional manifolds, with an application to a nonlinear master equation for vibrational relaxation. One of our main concerns is the asymptotic (in time) behavior of the system and whether there is a well-defined rate of approach to equilibrium. One-dimensional slow manifolds provide a good means for studying such behavior in nonlinear systems, because they are the analogue of the eigenvector with least negative eigenvalue for linear kinetics. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Davis, MJ (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 55 TC 10 Z9 10 U1 1 U2 3 PU R OLDENBOURG VERLAG PI MUNICH PA LEKTORAT M/N, K BERBER-NERLINGER, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY SN 0942-9352 J9 Z PHYS CHEM JI Z. Phys. Chemie-Int. J. Res. Phys. Chem. Chem. Phys. PY 2001 VL 215 BP 233 EP 252 DI 10.1524/zpch.2001.215.2.233 PN 2 PG 20 WC Chemistry, Physical SC Chemistry GA 405TC UT WOS:000167174800005 ER PT J AU von der Linde, D Sokolowski-Tinten, K Blome, C Dietrich, C Tarasevitch, A Cavalleri, A Squier, JA AF von der Linde, D Sokolowski-Tinten, K Blome, C Dietrich, C Tarasevitch, A Cavalleri, A Squier, JA TI 'Ultrafast' extended to X-rays: Femtosecond time-resolved X-ray diffraction SO ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS LA English DT Article DE femtosecond; X-ray; diffraction ID LASER-PRODUCED PLASMAS; LATTICE INSTABILITY; PULSES; DYNAMICS; SILICON; TRANSITIONS; ABSORPTION; GAAS; SI AB For a long time the capability to perform measurements with femtosecond time-resolution belonged exclusively to the domain of optics. However, in the last few years laser-driven X-ray sources have been developed which enable femtosecond time-resolution to be extended to the X-ray regime. C1 Univ Essen Gesamthsch, Inst Laser & Plasmaphys, D-45117 Essen, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP von der Linde, D (reprint author), Univ Essen Gesamthsch, Inst Laser & Plasmaphys, D-45117 Essen, Germany. RI Sokolowski-Tinten, Klaus/A-5415-2015 NR 27 TC 6 Z9 6 U1 1 U2 8 PU R OLDENBOURG VERLAG PI MUNICH PA LEKTORAT M/N, K BERBER-NERLINGER, POSTFACH 80 13 60, D-81613 MUNICH, GERMANY SN 0942-9352 J9 Z PHYS CHEM JI Z. Phys. Chemie-Int. J. Res. Phys. Chem. Chem. Phys. PY 2001 VL 215 BP 1527 EP 1541 PN 12 PG 15 WC Chemistry, Physical SC Chemistry GA 503ET UT WOS:000172786500004 ER PT J AU Valentine, GA Perry, FV WoldeGabriel, G AF Valentine, GA Perry, FV WoldeGabriel, G TI Field characteristics of deposits from spatter-rich pyroclastic density currents at Summer Coon volcano, Colorado SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE pyroclastic density; current Strombolian eruptions; ignimbrite ID ROCCAMONFINA VOLCANO; LITHIC BRECCIAS; FLOW DEPOSITS; CAMPI-FLEGREI; EMPLACEMENT; IGNIMBRITES; TRANSPORT; ERUPTION; ORIGIN; DYNAMICS AB The Oligocene, deeply eroded Summer Goon composite volcano contains mafic andesite deposits that are massive to poorly bedded, have abundant flattened and deformed spatter clasts, have Varying proportions of dense lithic clasts, and are supported mostly by a coarse-ash matrix. Although superficially these deposits resemble typical facies from Strombolian eruptions (emplaced ballistically, by fallout, and by rolling and local grain-avalanches down steep cone slopes), there are several Lines of evidence that lead to an interpretation that the deposits were emplaced by pyroclastic density currents. These include local coarse-tail grading, deformation of spatter clasts in a down-flow direction, incorporation of matrix ash and lapilli into flattened spatter clasts, imbrication of large clasts, plastering of spatter on stoss sides of large lithic blocks and lenses of lithic-rich material on lee sides, deposition on angles less than the angle of repose, and a paucity of clast shapes associated with Strombolian mechanisms. The deposit characteristics are consistent with rapid sedimentation from a low-particle-concentration, turbulent flow onto an aggrading bed. We infer two potential mechanisms for generating these density currents: (1) explosive magma-water interaction involving lithic debris and relatively unfragmented melt, and (2) collapse of oversteepened upper cone slopes due to rapid accumulation of spatter from voluminous Strombolian eruptions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Geoanal Grp EES5, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Integrated Geosci Grp EES13, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Geol Geochem Grp EES1, Los Alamos, NM 87545 USA. RP Valentine, GA (reprint author), Univ Calif Los Alamos Natl Lab, Geoanal Grp EES5, Mail Stop F665, Los Alamos, NM 87545 USA. NR 29 TC 18 Z9 18 U1 0 U2 3 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 DEC 30 PY 2000 VL 104 IS 1-4 BP 187 EP 199 DI 10.1016/S0377-0273(00)00206-7 PG 13 WC Geosciences, Multidisciplinary SC Geology GA 402DR UT WOS:000166971200011 ER PT J AU Yu, HG AF Yu, HG TI Quantum dynamics of the reaction of hydrogen atom with methane SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POTENTIAL-ENERGY SURFACE; H-2 REVERSIBLE CH4+H; RATE CONSTANTS; H+CH4->H-2+CH3 REACTION; SCATTERING; ABSTRACTION; ITERATION; EXCHANGE AB Time-independent quantum scattering calculations on the H + CH4 --> H-2 + CH3 reaction have been performed by using a four-dimensional rotating bond umbrella (RBU) model, based on a modified potential energy surface of Espinosa-Garcia and Corchado. The new surface gives a vibrationally adiabatic ground state barrier height of 14.1 kcal/mol. Calculated thermal rate constants are in good agreement with the experimental results. At room temperature the rate constant obtained is 8.16 x 10(-19) cm(3) molec(-1) s(-1). It is found that the simple energy minimization approximation gives significantly small thermal rate constants for this reaction. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Gothenburg Univ, Dept Chem, S-41296 Gothenburg, Sweden. RP Yu, HG (reprint author), Brookhaven Natl Lab, Dept Chem, Bldg 555, Upton, NY 11973 USA. RI Yu, Hua-Gen/N-7339-2015 NR 26 TC 34 Z9 35 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 29 PY 2000 VL 332 IS 5-6 BP 538 EP 544 DI 10.1016/S0009-2614(00)01313-0 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 389JY UT WOS:000166235900019 ER PT J AU Tolmachev, AV Kim, T Udseth, HR Smith, RD Bailey, TH Futrell, JH AF Tolmachev, AV Kim, T Udseth, HR Smith, RD Bailey, TH Futrell, JH TI Simulation-based optimization of the electrodynamic ion funnel for high sensitivity electrospray ionization mass spectrometry SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE electrospray; ion cooling; mass range; space charge; computer modeling; simulation ID COLLISION CROSS-SECTIONS; ATTOMOLE; CAPILLARIES; PRINCIPLES; INTERFACE; LEVEL AB High sensitivity is one of the most important requirements for applications of electrospray ionization mass spectrometry (ESI MS). Recent work with the electrodynamic ion funnel has demonstrated that it can provide significantly improved ion transmission through the ESI interface, Here we summarize the results of the simulations for several ion funnel configurations and their comparison with experimental measurements. We also report an alternative treatment of the ion funnel operation based on the effective potential approximation. The analytical relationships derived are used to generalize the results of computer simulations and develop an optimized ion funnel design. The new configuration reduces the spacing between ring electrodes to 1 mm and provides an optimized profile of the ring electrodes radii. It can also generate a deeper effective potential well, resulting in transmission of higher input ion currents over an extended mass range and increased operating pressure range (up to similar to 20 Torr). Furthermore, light m/z ion transmission is improved due to suppression of the effective potential wells near the ion funnel exit. Simulations for an optimized ion funnel configuration indicate unit transmission efficiency in the m/z range of interest for most biomolecular research using ESI (approximately m/z 100-5000), for 1-5 Ton pressure and ion currents >similar to1 nA, typical for low flow rate charge-constrained electrosprays (i.e. nanospray). Experimental results obtained with an improved electrodynamic funnel validate the model and demonstrate its general utility for designing rf-damped focusing elements. (C) 2000 Elsevier Science B.V. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA. RP Pacific NW Natl Lab, Environm Mol Sci Lab, MS K8-98,POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 34 TC 56 Z9 56 U1 5 U2 56 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 EI 1873-2798 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 29 PY 2000 VL 203 IS 1-3 BP 31 EP 47 DI 10.1016/S1387-3806(00)00265-7 PG 17 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 391DD UT WOS:000166338100004 ER PT J AU Gibson, JK Haire, RG AF Gibson, JK Haire, RG TI Gas-phase californium ion chemistry SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE californium; actinides; lanthanides; metal ion chemistry ID ORGANOMETALLIC CHEMISTRY; LANTHANIDE CATIONS; HYDROCARBON ACTIVATION; ENDOTHERMIC REACTIONS; CYCLIC HYDROCARBONS; ALKENES; METAL; REACTIVITY; COMPLEXES; FLUOROCARBONS AB The gas-phase chemistry of Cf+ was examined, this now being the heaviest element with which such studies have been performed. The emphasis was on the efficiency of dehydrogenation of alkenes by naked Cf+ direct comparison was made between the reactivities of Cf+ and those of Cm+, Pr+, and Tm+. The results with alkenes indicated that Cf+ is inefficient at C-H bond activation, in accord with a standard mechanistic model, and the reported electronic structure and predicted energy levels for Cf+. No participation of the quasivalence 5f electrons of Cf was indicated, and essentially lanthanidelike behavior was manifested. Other types of reactions were studied, including those of Cf with butryonitrile. butylamine. ethanedithiol, dimethylether. and perfluorocarbons. Several new Cf complex ions were identified, and novel aspects of Cf+ chemistry were assessed. (C) 2000 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Gibson, JK (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 51 TC 12 Z9 12 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 29 PY 2000 VL 203 IS 1-3 BP 127 EP 142 DI 10.1016/S1387-3806(00)00294-3 PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 391DD UT WOS:000166338100012 ER PT J AU Wells, JM Stephenson, JL McLuckey, SA AF Wells, JM Stephenson, JL McLuckey, SA TI Charge dependence of protonated insulin decompositions SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE insulin; electrospray ionization; unimolecular dissociation; ion/ion reaction; quadrupole ion trap ID TANDEM MASS-SPECTROMETRY; ASSISTED LASER-DESORPTION; QUADRUPOLE ION-TRAP; ELECTROSPRAY-IONIZATION; DISULFIDE BONDS; INDUCED DISSOCIATION; LINKED PEPTIDES; LARGE MOLECULES; PROTEINS; FRAGMENTATION AB Ion trap collisional activation is used to study the effects of charge state on protonated insulin decompositions for three forms of insulin: bovine, porcine, and human. Tandem mass spectrometry data are presented for ions with one to five protons dissociated under identical resonance excitation conditions. The (M+5H)(5+) and (M+4H)(4+) ions fragment exclusively by peptide bond cleavage of bonds outside the cycles formed by the disulfide linkages present in the insulin molecule, whereas the (M+3H)(3+) and (M+2H)(2+) ions appear to show a mixture of peptide bond cleavage and fragments arising from mechanisms associated with disulfide bond cleavage. The (M+H)(+) ion fragments almost exclusively by way of disulfide bond cleavage, with the only major exception being cleavage on the C-terminal side of glutamic acid residues external to the cycles formed by the disulfide linkages. (C) 2000 Elsevier Science B.V. C1 Purdue Univ, Dept Chem, Brown Lab 1393, W Lafayette, IN 47907 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP McLuckey, SA (reprint author), Purdue Univ, Dept Chem, Brown Lab 1393, W Lafayette, IN 47907 USA. RI Stephenson, James/A-9262-2009; McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 36 TC 72 Z9 72 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 29 PY 2000 VL 203 IS 1-3 BP A1 EP A9 DI 10.1016/S1387-3806(00)00389-4 PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 391DD UT WOS:000166338100001 ER PT J AU Matsika, S Pitzer, RM Reed, DT AF Matsika, S Pitzer, RM Reed, DT TI Intensities in the spectra of actinyl ions SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID FINE-STRUCTURE SPECTROSCOPY; RARE-EARTH IONS; ABSORPTION-SPECTRA; ELECTRONIC-STRUCTURE; MAGNETIC PROPERTIES; NEPTUNIUM IONS; ACID SOLUTION; URANYL; COMPLEXES; CHEMISTRY AB The absorption spectra of NpO2+ species in aqueous solution are investigated theoretically and experimentally, and the spectrum of NpO22+ species is investigated theoretically. The spectrum of NpO2+ in perchloric acid solution was taken from 350 to 1350 nm. Peak positions and optical densities are reported with overall uncertainties of 0.3 nm and 3%, respectively. A more precise value for the extinction coefficient of the most intense line is reported (398 +/- 4 M-1 cm(-1) for the 980.2 nm line). The intensities and positions of the electronic transitions of these actinyl complexes are computed from relativistic quantum chemical theory involving relativistic effective core potentials, corresponding spin-orbit operators, and spin-orbit, graphical unitary group configuration interaction. Because all of the low-lying electronic states for the isolated actinyl ions have the same parity, the equatorial ligands must break the inversion symmetry. Thus, model calculations on NpO2+ with one, three, and five chloride ligands were carried out; the five-ligand spectrum was quite similar to experimental solution spectra, whereas the one-ligand and three-ligand spectra were not. Calculations on NpO2(H2O)(5)(+) were then made in order to provide a close comparison with experimental results. Similar calculations on NpO2(H2O)(5)(2+) were also carried out but were hampered by the difficulty in doing sufficiently extensive calculations to determine the ground electronic state with the ligands present. Comparisons were made, nevertheless, using both of the candidates for ground state. A simplified crystal-field theory is developed to show how the necessary symmetry-breaking orbital mixing, 5f phi with 6d delta, occurs selectively with 5-fold coordination. C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Pitzer, RM (reprint author), Ohio State Univ, Dept Chem, 100 W 18Th Ave, Columbus, OH 43210 USA. EM pitzer.3@osu.edu NR 47 TC 49 Z9 50 U1 2 U2 16 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 DEC 28 PY 2000 VL 104 IS 51 BP 11983 EP 11992 DI 10.1021/jp002580s PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 388CM UT WOS:000166159900018 ER PT J AU Micic, OI Smith, BB Nozik, AJ AF Micic, OI Smith, BB Nozik, AJ TI Core-shell quantum dots of lattice-matched ZnCdSe2 shells on InP cores: Experiment and theory SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID STRONG LUMINESCING CDS; EPITAXIAL-GROWTH; WELL CDS/HGS/CDS; PARTICLES; NANOCRYSTALS; PHOTOCHEMISTRY; NANOPARTICLES; PHOTOPHYSICS; COLLOIDS AB Lattice-matched ZnCdSe2 concentric epilayer shells up to 50 Angstrom in thickness have been grown on InP core quantum dots (QDs). The quality of the epitaxially grown shells was monitored by absorption and emission spectra and transmission electron microscopy (TEM). Shell growth was shown to be controllable and was consistently accompanied by a large red shift of the absorption and emission spectra. This results from increased electron delocalization and, hence, lower confinement energy compared to core QDs with no shell. Core-shell nanocrystals also show higher quantum yields for emission since the interface of the QDs is better passivated and deep surface trap luminescence is converted into band-edge luminescence. Theoretical calculations of the electron probability density in these core-shell QDs were made using high-level self-consistent field and tight-binding methods; the theoretical results are consistent with the experimental results. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Colorado, Dept Chem, Boulder, CO 80309 USA. RP Micic, OI (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Nozik, Arthur/A-1481-2012; Nozik, Arthur/P-2641-2016 NR 37 TC 78 Z9 79 U1 4 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 28 PY 2000 VL 104 IS 51 BP 12149 EP 12156 DI 10.1021/jp0021502 PG 8 WC Chemistry, Physical SC Chemistry GA 388DE UT WOS:000166161500011 ER PT J AU Hijar, CA Jacubinas, RM Eckert, J Henson, NJ Hay, PJ Ott, KC AF Hijar, CA Jacubinas, RM Eckert, J Henson, NJ Hay, PJ Ott, KC TI The siting of Ti in TS-1 is non-random. Powder neutron diffraction studies and theoretical calculations of TS-1 and FeS-1 SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ZEOLITE ZSM-5; SEMIEMPIRICAL METHODS; MOLECULAR-SIEVE; TITANIUM; IRON; FRAMEWORK; SILICALITE; EXAFS; SUBSTITUTION; SITES AB We present the first direct evidence of non random siting of Ti and Fe in TS-1 and FeS-1, nanoporous metallosilicate selective oxidation catalysts of MFI topology. This was accomplished by using Rietveld analysis of powder neutron diffraction data and exploiting the differences in neutron scattering lengths between Ti or Fe and Si. Previous spectroscopic, X-ray diffraction, and computational approaches have suggested a random substitution of Ti and Fe ions among the 12 crystallographically distinct Si sites in the framework of TS-1 and FeS-1. In contrast, our results indicate that titanium is distributed among only 4 or 5 of the 12 silicon sites with Ti occupying T3, -7, -8, -10, and -12. Of the 2.47 total Ti atoms per unit cell the Ti site occupancies and estimated standard deviation for sample B are as follows: T3 0.30(0.11), T7 0.34(0.14), TX 0.92(0.10), T10 0.41(0.14), and T12 0.50(0.14). In FeS-1 synthesized with 1.5 Fe atoms per unit cell, iron is found only at T8. Several starting models were chosen for initial refinement, and each returned the same specific, nonrandom distribution of Ti in the framework of MFI. We have examined several computational approaches that involve thermodynamic arguments to rationalize the experimental observations, and all have failed to predict the experimentally observed substitution pattern, This suggests that the kinetics of framework formation may play a role in directing the observed metal substitution. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Ott, KC (reprint author), Univ Calif Los Alamos Natl Lab, MS J514, Los Alamos, NM 87545 USA. NR 48 TC 56 Z9 57 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 28 PY 2000 VL 104 IS 51 BP 12157 EP 12164 DI 10.1021/jp002167k PG 8 WC Chemistry, Physical SC Chemistry GA 388DE UT WOS:000166161500012 ER PT J AU Gilardoni, F Bell, AT Chakraborty, A Boulet, P AF Gilardoni, F Bell, AT Chakraborty, A Boulet, P TI Density functional theory calculations of the oxidative dehydrogenation of propane on the (010) surface of V2O5 SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID DIATOMIC DIFFERENTIAL-OVERLAP; NONEMPIRICAL WAVE-FUNCTIONS; VANADIUM-OXIDE CATALYSTS; INHOMOGENEOUS ELECTRON-GAS; TRANSITION-METAL-COMPLEXES; REACTIVITY INDEXES; PARTIAL RETENTION; LARGE MOLECULES; CHEMICAL-REACTIVITY; PRDDO/M/FCP METHOD AB Density functional theory and the calculations of oxygen nucleophilicity have been applied to an analysis of the oxidative dehydrogenation (ODH) of propane on the (010) surface of V2O5. These calculations show that the energetically preferred initial step is the dissociative adsorption of propane to form i-propoxide and hydroxyl species. Two V=O groups [O(1)] bonded by a V-O-V bridge are required. One of the vanadyl groups attacks the beta -C atom of propane and is converted to a V-OCH2(CH3)(2) species, whereas the ether vanadyl group is converted into a V-OH group. The activation barrier for this process is 9.4 kcal/mol. Dissociative adsorption to form an n-propoxide can also occur, but the activation barrier for this process is 14.5 kcal/mol. Propene and water are formed via a concerted process in which an H atom of one of the methyl groups of i-propoxide reacts with an O(3)H group. Exploration of alternative pathways for this step reveals that neither O(1, 2, 3), O(1)H, nor O(2)H are sufficiently reactive. These findings are in good qualitative agreement with experimental observations concerning the mechanism and kinetics of propane ODH. C1 Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Geneva, Dept Phys Chem, CH-1211 Geneva 4, Switzerland. RP Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RI Boulet, Pascal/A-1332-2011 OI Boulet, Pascal/0000-0001-8051-4287 NR 55 TC 52 Z9 53 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 28 PY 2000 VL 104 IS 51 BP 12250 EP 12255 DI 10.1021/jp001746m PG 6 WC Chemistry, Physical SC Chemistry GA 388DE UT WOS:000166161500024 ER PT J AU Manna, L Scher, EC Alivisatos, AP AF Manna, L Scher, EC Alivisatos, AP TI Synthesis of soluble and processable rod-, arrow-, teardrop-, and tetrapod-shaped CdSe nanocrystals SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ZINC-OXIDE WHISKERS; CHEMICAL-VAPOR-DEPOSITION; EPITAXIAL-GROWTH; GOLD NANORODS; QUANTUM DOTS; NANOWIRES; NANOPARTICLES; CHEMISTRY; SEMICONDUCTORS; ORGANIZATION AB The formation of extremely high aspect ratio CdSe nanorods (30:1) as well as arrow-, teardrop-, tetrapod-, and branched tetrapod-shaped nanocrystals of CdSe, has been achieved by growth of the nanoparticles in a mixture of hexylphosphonic acid and trioctylphosphine oxide. The most influential factors in shape control are the ratio of surfactants, injection volume, and time-dependent monomer concentration. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Alivisatos, AP (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Manna, Liberato/G-2339-2010; Alivisatos , Paul /N-8863-2015 OI Manna, Liberato/0000-0003-4386-7985; Alivisatos , Paul /0000-0001-6895-9048 NR 35 TC 1455 Z9 1479 U1 39 U2 489 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 DEC 27 PY 2000 VL 122 IS 51 BP 12700 EP 12706 DI 10.1021/ja003055+ PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 386DN UT WOS:000166045000012 ER PT J AU Asbury, JB Hang, K Yeston, JS Cordaro, JG Bergman, RG Lian, TQ AF Asbury, JB Hang, K Yeston, JS Cordaro, JG Bergman, RG Lian, TQ TI Direct observation of a picosecond alkane C-H bond activation reaction at iridium SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DICARBONYL COMPLEXES; OXIDATIVE ADDITION; METAL-COMPLEXES; IR; FEMTOSECOND; MECHANISM; METHANE; SPECTROSCOPY; KINETICS; RATES C1 Emory Univ, Dept Chem, Atlanta, GA 30322 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Lian, TQ (reprint author), Emory Univ, Dept Chem, 1515 Pierce Dr, Atlanta, GA 30322 USA. RI Lian, Tianquan/L-8992-2013 OI Lian, Tianquan/0000-0002-8351-3690 NR 24 TC 23 Z9 23 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD DEC 27 PY 2000 VL 122 IS 51 BP 12870 EP 12871 DI 10.1021/ja0028065 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 386DN UT WOS:000166045000035 ER PT J AU Steere, B Eisenberg, D AF Steere, B Eisenberg, D TI Characterization of high-order diphtheria toxin oligomers SO BIOCHEMISTRY LA English DT Article ID REFINED STRUCTURE; FRAGMENT; DOMAIN; RECEPTOR; PH; PURIFICATION; RESOLUTION; MEMBRANES; CHANNELS; ENTRY AB In 3D domain swapping, a domain of a protein breaks its noncovalent bends with the protein core and its place is taken by the identical domain of another molecule, creating a strongly bound dimer or higher order oligomer. For some proteins, including diphtheria toxin, 3D domain swapping may affect protein function. To explore the molecular basis of 3D domain swapping in a well-characterized protein system, domain-swapped oligomers of diphtheria toxin were produced by freezing and thawing under a variety conditions, including in various salts and buffers, and at various temperatures. Reaction yields were followed by high-performance size-exclusion chromatography. The traditional low pH pulse produced by freeze-thawing in mixed sodium phosphate buffer induces the oligomerization of DT, but the addition of alkali chloride salts was found to increase the yield in the order of Li+ > Na+ > K+. Unexpectedly, oligomers also formed when DT was frozen and thawed in the presence of 1 M LiCl alone. Slower freezing and thawing of the mixture led to the production of more and larger oligomers. DT oligomers were also produced by exposure to acidic buffers, and were found by electron microscopy to adopt both linear and cyclized forms in a wide distribution of sizes. Upon the basis of these results, the model for the production of DT oligomers by freezing and thawing was expanded to include a salt-mediated pathway. We present a mechanism for the formation of high-order DT oligomers by acidification that takes into account domain swapping and hydrophobic interactions. C1 Univ Calif Los Angeles, UCLA DOE Lab Struct Biol & Mol Med, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. RP Eisenberg, D (reprint author), Univ Calif Los Angeles, UCLA DOE Lab Struct Biol & Mol Med, POB 951570, Los Angeles, CA 90095 USA. FU NIGMS NIH HHS [5-T32-GM-07185, GM31299] NR 28 TC 19 Z9 19 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD DEC 26 PY 2000 VL 39 IS 51 BP 15901 EP 15909 DI 10.1021/bi0011678 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 386PD UT WOS:000166070000029 PM 11123917 ER PT J AU Jirsak, T Rodriguez, JA AF Jirsak, T Rodriguez, JA TI Chemistry of NO2 and SO2 on ice layers and H2O/Zn interfaces: Photoemission studies on the formation of acid water and metal corrosion SO LANGMUIR LA English DT Article ID SURFACE-CHEMISTRY; NITROGEN-DIOXIDE; ANTARCTIC OZONE; ADSORPTION; FILMS; OXIDATION; DEPLETION; AG(110); OXYGEN; ZNO AB Synchrotron-based photoelectron spectroscopy was used to study adsorption of sulfur dioxide and nitrogen dioxide on ice multilayers deposited on zinc. The formation of acid water (H2O/HxSO4 or H2O/HxNO3) and the corrosion of the underlying Zn metal were investigated. Small. amounts of dosed SO2 react with an ice multilayer at 100 K producing sulfuric acid-like species (HxSO4) on the surface. Extensive dosing leads to a condensed SO2 multilayer which is thermally unstable and desorbs upon mild heating to 130-150 K. Above 170 K, when also the ice multilayer desorbs, the only sulfur species on the Zn surface is HxSO4. The {H2O/HxSO4} mixture eventually oxidizes the metal, and the adsorbed SO4 groups are stable to at least 350 K. At 100 K, the initial stage of a NO2 adsorption on ice is nonreactive. NO2 reacts with ice only at higher exposures, producing a small amount of nitric acid-like species (HxNO3), followed by condensation of an O2N-NO2 multilayer. The N2O4 multilayer partially desorbs at temperatures around 150 K and partially reacts with ice, producing more HxNO3. This species transforms to HxNO2 (perhaps MONO) or chemisorbed NO2 upon removal of the ice multilayer (above 170 K). Further decomposition of HxNO2 occurs between 250 and 350 K, and then the Zn surface is essentially free of any nitrogen species but contains lots of oxygen. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Acad Sci Czech Republ, J Heyrovsky Inst Phys Chem & Electrochem, CR-18223 Prague 8, Czech Republic. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 32 TC 11 Z9 11 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 26 PY 2000 VL 16 IS 26 BP 10287 EP 10293 DI 10.1021/la009700 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 388DG UT WOS:000166161700052 ER PT J AU Strzalka, J Chen, XX Moser, CC Dutton, PL Ocko, BM Blasie, JK AF Strzalka, J Chen, XX Moser, CC Dutton, PL Ocko, BM Blasie, JK TI X-ray scattering studies of maquette peptide monolayers. 1. Reflectivity and grazing incidence diffraction at the air/water interface SO LANGMUIR LA English DT Article ID PROFILE STRUCTURES; PROTEIN; SURFACE; MULTILAYERS; SCAFFOLD; DESIGN; FILMS AB We present isotherm and X-ray reflectivity (XR) measurements from Langmuir monolayers of a de novo synthetic di-alpha -helical peptide; consisting of two identical 31-residue, mostly alpha -helical peptide units joined by a disulfide bond at their amino-termini. Fitting the XR data to slab models shows that the dihelices lie in the plane of the interface at low pressures. The monolayers were insufficiently stable for study at high pressures, but Langmuir films based on a derivative of the peptide alkylated at its amino termini permitted investigations over a larger range of pressures. We observed an orientational transition, in which the alpha -helices begin by lying in the plane of the interface at low surface pressures and orient themselves approximately normal to the interface at high pressures. We draw the same conclusions from the XR data when we analyze it using box refinement, an iterative, model-independent method for recovering structure from XR data. Mixtures of these palmitoylated peptides with a fatty acid (palmitic acid) or a phospholipid (DLPE) behaved similarly. None of the systems produced peaks in the grazing incidence diffraction signal indicative of long-range ordering of the upright a-helices. Off-specular in-plane scattering measurements based on the difference signal between the peptide/DLPE mixture and pure DLPE suggest that the peptide achieves only liquidlike order within the plane. We discuss the implications and prospects for future work on designed peptide monolayers incorporating prosthetic groups that could be used to study electron transfer in proteins and provide a basis for biomolecular electronics applications. C1 Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. Univ Penn, Dept Biochem & Biophys, Philadelphia, PA 19104 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Strzalka, J (reprint author), Univ Penn, Dept Chem, Box 141, Philadelphia, PA 19104 USA. OI Chen, Xiaoxi/0000-0002-1049-3537; Strzalka, Joseph/0000-0003-4619-8932 NR 28 TC 22 Z9 22 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 26 PY 2000 VL 16 IS 26 BP 10404 EP 10418 DI 10.1021/la000264z PG 15 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 388DG UT WOS:000166161700068 ER PT J AU Striolo, A Prausnitz, JM Bertucco, A AF Striolo, A Prausnitz, JM Bertucco, A TI Osmotic second virial coefficient, intrinsic viscosity and molecular simulation for star and linear polystyrenes SO MACROMOLECULES LA English DT Article ID ANGLE NEUTRON-SCATTERING; THETA-TEMPERATURE; DILUTE-SOLUTION; BRANCHED POLYMERS; LIGHT-SCATTERING; GOOD-SOLVENT; MONTE-CARLO; GLOBULE TRANSITION; PHASE-SEPARATION; CYCLOHEXANE AB Experimental osmotic second virial coefficients are reported for polystyrene in toluene (good solvent), cyclohexane (Theta solvent) and methylcyclohexane (poor solvent) in the temperature range 10-60 degreesC. The Theta temperature for eight arm star polystyrene in methylcyclohexane is 29 +/- 3 degreesC. Intrinsic viscosity for polystyrene in cyclohexane and methylcyclohexane has been measured over a wide temperature range. A coil-globule transition has been observed for eight-arm star polystyrene in methylcyclohexane at temperatures close to the Theta temperature. The Theta point for star polymers with three, four, five, and six arms have been determined by standard Monte Carlo simulation calculations. For six-arm star polymers at the Theta point, defined as the well depth at which the radius of gyration squared scales linearly with the number of segments, the osmotic second virial coefficient is zero. As shown by others, for a branched polymer, the osmotic second virial coefficient at good solvent conditions and the Theta temperature are lower than those for a corresponding linear homologue in the same solvent. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Padua, Ist Impianti Chim, I-35131 Padua, Italy. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Striolo, Alberto/G-2926-2011 NR 35 TC 10 Z9 10 U1 3 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD DEC 26 PY 2000 VL 33 IS 26 BP 9583 EP 9586 DI 10.1021/ma000348e PG 4 WC Polymer Science SC Polymer Science GA 388PJ UT WOS:000166189900019 ER PT J AU Johnson, JA Grimsditch, M Metlushko, V Vavassori, P Ilic, B Neuzil, P Kumar, R AF Johnson, JA Grimsditch, M Metlushko, V Vavassori, P Ilic, B Neuzil, P Kumar, R TI Magneto-optic Kerr effect investigation of cobalt and permalloy nanoscale dot arrays: Shape effects on magnetization reversal SO APPLIED PHYSICS LETTERS LA English DT Article ID SWITCHING FIELD; CO DOTS; LITHOGRAPHY; ELEMENTS AB Using the magneto-optic Kerr effect (MOKE) and magnetic force microscopy we have investigated the shape dependence of magnetization reversal in a series of cobalt and permalloy nanoscale dot arrays. The patterns were produced by e-beam lithography combined with e-beam deposition and lift-off techniques. To avoid pattern to pattern variations in growth-induced anisotropy and or thickness, elliptical elements of varying aspect ratio were deposited simultaneously on a single substrate. All arrays were 1.0x2.5 mum tetragonal lattices and were fabricated with 300 Angstrom thickness of cobalt and with 200 and 300 Angstrom thickness of permalloy. From MOKE data we extract the field at which the onset of switching occurs for each array. For each material (viz. Co or permalloy), and thickness (200 or 300 Angstrom), the switching field versus aspect ratio can be interpreted by a single nucleation field. The dependence of the nucleation barrier on the material and its thickness is discussed. (C) 2000 American Institute of Physics. [S0003-6951(00)00647-1]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Elect Engn & Comp Sci, Chicago, IL 60607 USA. Univ Ferrara, Dipartmento Fis, I-44100 Ferrara, Italy. Univ Ferrara, INFM, I-44100 Ferrara, Italy. Cornell Univ, Sch Appl & Engn Phys, Ithaca, NY 14853 USA. Inst Microelect, Singapore 117685, Singapore. RP Johnson, JA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Neuzil, Pavel/B-9981-2012; Ilic, Rob/N-1359-2014; Johnson, Jacqueline/P-4844-2014; Vavassori, Paolo/B-4299-2014 OI Johnson, Jacqueline/0000-0003-0830-9275; Vavassori, Paolo/0000-0002-4735-6640 NR 24 TC 27 Z9 28 U1 2 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 25 PY 2000 VL 77 IS 26 BP 4410 EP 4412 DI 10.1063/1.1326841 PG 3 WC Physics, Applied SC Physics GA 387JY UT WOS:000166120500056 ER PT J AU Walker, DW Li, M Rana, OF Shields, MS Huang, Y AF Walker, DW Li, M Rana, OF Shields, MS Huang, Y TI The software architecture of a distributed problem-solving environment SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article DE problem-solving environment; distributed computing; CORBA; component-based software ID COMPUTATIONAL SCIENCE AB This paper describes the functionality and software architecture of a generic problem-solving environment (PSE) for collaborative computational science and engineering, A PSE is designed to provide transparent access to heterogeneous distributed computing resources, and is intended to enhance research productivity by making it easier to construct, run, and analyze the results of computer simulations, Although implementation details are not discussed in depth, the role of software technologies such as CORBA, Java, and XML is outlined, An XML-based component model is presented, The main features of a Visual Component Composition Environment for software development, and an Intelligent Resource Management System for scheduling components, are described. Some prototype implementations of PSE applications are also presented. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. Cardiff Univ, Dept Comp Sci, Cardiff CF24 3XF, S Glam, Wales. RP Walker, DW (reprint author), Oak Ridge Natl Lab, Div Math & Comp Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Walker, David/B-7978-2010; OI Walker, David/0000-0002-1360-6330 NR 34 TC 34 Z9 34 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD DEC 25 PY 2000 VL 12 IS 15 BP 1455 EP 1480 DI 10.1002/1096-9128(20001225)12:15<1455::AID-CPE538>3.0.CO;2-# PG 26 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 395ZJ UT WOS:000166611600001 ER PT J AU D'Azevedo, E Dongarra, J AF D'Azevedo, E Dongarra, J TI The design and implementation of the parallel out-of-core ScaLAPACK LU, QR, and Cholesky factorization routines SO CONCURRENCY-PRACTICE AND EXPERIENCE LA English DT Article DE linear solver; out-of-core solver; LU factorization; numerical library ID SCATTERING PROBLEMS; COMPUTATION AB This paper describes the design and implementation of three core factorization routines-LU, QR, and Cholesky-included in the out-of-core extension of ScaLAPACK, These routines allow the factorization and solution of a dense system that is too large to fit entirely in physical memory, The full matrix is stored on disk and the factorization routines transfer submatrice panels into memory. The 'left-looking' column-oriented variant of the factorization algorithm is implemented to reduce the disk I/O traffic, The routines are implemented using a portable I/O interface and utilize high-performance ScaLAPACK factorization routines as in-core computational kernels. We present the details of the implementation for the out-of-core ScaLAPACK factorization routines, as Well as performance and scalability results on a Beowulf Linux cluster. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Comp Sci, Oak Ridge Natl Lab, Div Math & Comp Sci, Knoxville, TN 37996 USA. RP D'Azevedo, E (reprint author), Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. RI Dongarra, Jack/E-3987-2014 NR 22 TC 16 Z9 16 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1040-3108 J9 CONCURRENCY-PRACT EX JI Concurrency-Pract. Exp. PD DEC 25 PY 2000 VL 12 IS 15 BP 1481 EP 1493 DI 10.1002/1096-9128(20001225)12:15<1481::AID-CPE540>3.0.CO;2-V PG 13 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 395ZJ UT WOS:000166611600002 ER PT J AU Frank, P Hodgson, KO AF Frank, P Hodgson, KO TI Defining chemical species in complex environments using K-edge X-ray absorption spectroscopy: Vanadium in intact blood cells and Henze solution from the tunicate Ascidia ceratodes SO INORGANIC CHEMISTRY LA English DT Article ID PHALLUSIA-MAMMILLATA CUVIER; FINE-STRUCTURE SPECTROSCOPY; METAL-LIGAND COVALENCY; WHOLE-BLOOD; CYTOCHEMICAL-LOCALIZATION; BIOLOGICAL-SYSTEMS; OXIDATION-STATE; MENTULA MULLER; MORULA CELLS; SULFUR AB A K-edge X-ray absorption spectrum (XAS) fitting approach has been developed to speciate elements of interest in complex materials and used hen to model the storage of biological vanadium within whole blood cells from the tunicate Ascidia ceratodes. The response of the K-edge XAS of solution-phase V(III) to increasing c(sulfate) at constant pH 1.8 produced specific and systematic effects in the preedge transition at 5468.8 eV (preedge transitions: 1s --> (4)A(2) at 5464.9 +/- 0.1 eV, 1s --> T-4(2) at 5466.9 +/- 0.1 eV, and 1s --> T-4(1) at 5468.8 +/- 0.1 eV for 11 different V(III)/sulfate solutions). In contrast, variations in acidity (as pH) at constant c(sulfate) systematically modified the V(III) preedge XAS at 5466.9 eV. The energy position of the K-edge absorption maximum also serially shifted -0.32 eV/pH unit, from 5483.7 eV (pH 3.0) to 5484.7 eV (pH 0.3). Fits to the V-IC XAS of two samples of A. ceratodes whale blood cells representing dozens of animals implied storage of V(III) ions in four predominant solution regimes: similar to 10% high sulfate/pH 0 acid; similar to 40% high sulfate/pH 1.8 acid; similar to 40% moderate sulfate/pH 1.8 acid; similar to 10% moderate sulfate/pH 3 acid. For lysed blood cells, the best fit represented 63% of the V(III) in a pH 1.6 sulfate-free environment and a further 16% in acidic sulfate solution. Nearly 18% of lysed cells vanadium(III) appeared in a tris(catecholate)-like environment. A detailed speciation of biological vanadium complex ions was calculated from these fits by application of the known equilibrium constants governing V(III) and sulfate in acidic aqueous solution. The utility of blood cell V(TLI) to ascidians is discussed. Fits to K-edge XAS spectra using the XAS spectra of appropriate models are suggested to be generally applicable to elucidating the state of metal ions in a wide variety of complex environments. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. RP Hodgson, KO (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. FU NCRR NIH HHS [RR-01209] NR 81 TC 35 Z9 36 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD DEC 25 PY 2000 VL 39 IS 26 BP 6018 EP 6027 DI 10.1021/ic000546m PG 10 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 385TF UT WOS:000166019200018 PM 11151502 ER PT J AU Dahl, DA AF Dahl, DA TI SIMION for the personal computer in reflection SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion optics ID DESIGN AB This article is a reflective overview of the origins, history, and capabilities of the ion optics simulation program SIMION for the PC (versions 2.0-7.0) from the author's perspective. It provides insight into the rationale and events that contributed to the direction of the evolution and current capabilities of the program. The capabilities of version 7.0 are presented along with tests of its computational accuracy. Future developmental areas are discussed. (C) 2000 Elsevier Science B.V. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Dahl, DA (reprint author), Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. NR 11 TC 221 Z9 224 U1 3 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 25 PY 2000 VL 200 IS 1-3 BP 3 EP 25 DI 10.1016/S1387-3806(00)00305-5 PG 23 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 388KB UT WOS:000166178700002 ER PT J AU McLuckey, SA Wells, JM Stephenson, JL Goeringer, DE AF McLuckey, SA Wells, JM Stephenson, JL Goeringer, DE TI Novel quadrupole ion trap methods for characterizing the chemistry of gaseous macro-ions SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Review DE quadrupole ion trap; macro-ion; unimolecular dissociation; ion/molecule reaction; ion/ion reaction ID TANDEM MASS-SPECTROMETRY; PROTON-TRANSFER REACTIONS; MULTIPLY-CHARGED IONS; COLLISION-INDUCED DISSOCIATION; INFRARED RADIATIVE DISSOCIATION; SURFACE-INDUCED DISSOCIATION; GAS-PHASE PROTEINS; PANCREATIC TRYPSIN-INHIBITOR; SMALL CLUSTER IONS; ELECTROSPRAY-IONIZATION AB A variety of ion manipulation techniques that have been developed to study the chemistry of gas-phase macro-ions are described and illustrated. These techniques take advantage of several unique characteristics of the quadrupole ion trap, including operation at relatively high (1 mTorr) bath gas pressure and the ability to simultaneously store positive and negative ions in overlapping regions of space. Efforts to characterize unimolecular dissociation in the ion trap via resonance excitation and thermal dissociation at elevated bath gas temperatures are described; such dissociation is of interest as a means for obtaining primary structural information and Arrhenius activation parameters for macro-ions. The use of ion/molecule chemistry to obtain composition and higher level structural information is illustrated with a description of novel HI attachment chemistry which yields information on the number and accessibility of neutral basic sites in macro-ions. Ion/ion chemistry for the manipulation of parent and product ion charge states is shown to expand the range of charge states accessible for tandem mass spectrometry (MS/MS) analysis, and to greatly simplify the interpretation of MS/MS spectra obtained from multiply charged parent ions. (C) 2000 Elsevier Science B.V. C1 Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN USA. RP Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. EM mcluckey@purdue.edu RI Stephenson, James/A-9262-2009; McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 147 TC 16 Z9 16 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 EI 1873-2798 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 25 PY 2000 VL 200 IS 1-3 BP 137 EP 161 DI 10.1016/S1387-3806(00)00306-7 PG 25 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 388KB UT WOS:000166178700009 ER PT J AU Ng, CY AF Ng, CY TI Vacuum ultraviolet photoionization and photoelectron studies in the new millennium: recent developments and applications SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Review DE photoionization; photoelectron; pulsed field ionization; vacuum ultraviolet; synchrotron radiation; photoelectron-photoion coincidence ID PULSED-FIELD IONIZATION; HIGH-RESOLUTION THRESHOLD; ADVANCED LIGHT-SOURCE; MULTIBUNCH SYNCHROTRON-RADIATION; KINETIC-ENERGY SPECTROSCOPY; FLIGHT SELECTION SCHEME; ION-MOLECULE REACTIONS; HIGH-FLUX BEAMLINE; RYDBERG STATES; COINCIDENCE SPECTROSCOPY AB Vacuum ultraviolet (VUV) photoionization mass spectrometry and photoelectron spectroscopy have played a central role in providing energetic and spectroscopic information for neutrals and cations. The most important data obtainable in a VUV photoionization and photoelectron experiment are ionization energies and 0 K ion dissociation thresholds or appearance energy (AE), from which 0 K bond dissociation energies for neutrals and cations can be deduced. The recent developments in VUV lasers and third-generation synchrotron sources, together with the introduction of the pulsed-field ionization (PFI), photoelectron (PFI-PE), and PFI-photoion (PFI-PI) methods, have revolutionized the field of photoelectron and ion spectroscopy by significantly improving the energy resolution to the range of 0.025-1.0 meV (full width at half maximum, FWHM). These resolutions, which make possible the measurement of photoelectron spectra for many simple molecules at the rotational-resolved level, are approximate to 100-fold better than those observed in traditional photoelectron studies, making the PFI-PE technique a true spectroscopic method. The recent introduction of the synchrotron-based PFI-PEPICO scheme has shown that AE values for a range of molecules can be determined with an unprecedented precision limited only by the PFI-PE measurement. The synchrotron-based PFI-PEPICO and PFI-PI schemes show great promises for future studies of state- or energy-selected ion-dissociation dynamics and energy-selected ion-molecule reaction dynamics. Further improvement in energy resolution for PFI-PE and PFI-PI measurements has been demonstrated using the two-color photo-induced Rydberg ionization (PIRI) spectroscopic scheme, which involves the photo-induced ionization of intermediate long-lived high-n (n greater than or equal to 100) Rydberg states. The incorporation of this method by VUV photoexcitation to prepare intermediate high-n (n greater than or equal to 100) Rydberg states is also expected to greatly increase the energy range of PFI studies. The availability of this array of laser- and synchrotron-based PFI methods, including PFI-PE, PFI-PEPICO, PFI-PI, PFI-ion-pair, and PIRI schemes, ensures an exciting and bright future for VUV photoionization and photoelectron studies in the new millennium. (C) 2000 Elsevier Science B.V. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP US DOE, Ames Lab, Ames, IA 50011 USA. EM cyng@ameslab.gov NR 129 TC 34 Z9 35 U1 4 U2 28 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 EI 1873-2798 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 25 PY 2000 VL 200 IS 1-3 BP 357 EP 386 DI 10.1016/S1387-3806(00)00348-1 PG 30 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 388KB UT WOS:000166178700022 ER PT J AU Futrell, JH AF Futrell, JH TI Development of tandem mass spectrometry: one perspective SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE tandem mass spectrometry; MS/MS; collisional activation; ion cyclotron resonance; crossed-beam ID COLLISION-INDUCED DISSOCIATION; DIFFERENTIAL CROSS-SECTIONS; LOW-ENERGY; ELASTIC-SCATTERING; BEAM MEASUREMENTS; POLYATOMIC IONS; CHARGE-EXCHANGE; ACETONE CATION; DYNAMICS; AR AB The historical roots of tandem mass spectrometry or MS/MS (an invaluable tool for determining molecular structure and mixture analysis) are reviewed from the perspective of an active participant. The driving force for creating the first (and only) five-sector tandem mass spectrometer in the period 1962-1965 was to establish mechanisms of low energy ion-molecule reactions unequivocally and to evaluate the dependence of these reactions an ion kinetic energy. The invention and deployment of several other specialized instruments in the 1970s (drift cell and tandem ion cyclotron resonance spectrometers, hybrid tandems, and triple quadrupole instruments) also had fundamental studies of ion reactions as the research objective. The focus on low energy ion chemistry has evolved into collisional activation, the basis of analytical applications of MS/MS, as a natural evolution of scientific interest. The first such studies utilizing a crossed-beam hybrid MS/MS addressed single collision gas phase activation and has recently been extended to surface collision activation. The important parallel development of these methods and the metamorphosis of MS/MS from a suite of research tools into analytical practice using commercial instrumentation are discussed briefly. (C) 2000 Elsevier Science B.V. C1 Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Futrell, JH (reprint author), Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, POB 999,K8-84, Richland, WA 99352 USA. NR 86 TC 9 Z9 9 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 25 PY 2000 VL 200 IS 1-3 BP 495 EP 508 DI 10.1016/S1387-3806(00)00353-5 PG 14 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 388KB UT WOS:000166178700029 ER PT J AU Smith, RD AF Smith, RD TI Evolution of ESI-mass spectrometry and Fourier transform ion cyclotron resonance for proteomics and other biological applications SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Review DE electrospray ionization; FTICR mass spectrometry; proteomics; capillary electrophoresis; proteins ID SUPERCRITICAL FLUID SOLUTIONS; MULTIPLY-CHARGED IONS; CAPILLARY ZONE ELECTROPHORESIS; MOLECULAR-WEIGHT DETERMINATION; COMPLEX PROTEIN MIXTURES; ELECTROSPRAY-IONIZATION; GAS-PHASE; CYTOCHROME-C; NONCOVALENT COMPLEXES; SEQUENCE INFORMATION AB A perspective is presented centered on the author's contributions to developments involving electrospray ionization-mass spectrometry, capillary electrophoresis-mass spectrometry, and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry and their applications to biological systems, with a special emphasis on the study of noncovalent complexes and proteomics. (C) 2000 Elsevier Science B.V. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Pacific NW Natl Lab, Environm Mol Sci Lab, Mail Stop K8-98,POB 999, Richland, WA 99352 USA. EM rd_smith@pnl.gov RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 104 TC 64 Z9 66 U1 2 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 EI 1873-2798 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD DEC 25 PY 2000 VL 200 IS 1-3 BP 509 EP 544 DI 10.1016/S1387-3806(00)00352-3 PG 36 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 388KB UT WOS:000166178700030 ER PT J AU Gineitis, AA Zalenskaya, IA Yau, PM Bradbury, EM Zalensky, AO AF Gineitis, AA Zalenskaya, IA Yau, PM Bradbury, EM Zalensky, AO TI Human sperm telomere-binding complex involves histone H2B and secures telomere membrane attachment SO JOURNAL OF CELL BIOLOGY LA English DT Article DE sperm; telomere; histone H2B; nuclear membrane ID DEFINED GENOME ARCHITECTURE; MOLECULAR-CLONING; MEIOTIC PROPHASE; CHROMOSOME ENDS; CHROMATIN; LAMIN; EXPRESSION; PROTEIN; CELLS; SPERMATOGENESIS AB Telomeres are unique chromatin domains located at the ends of eukaryotic chromosomes. Telomere functions in somatic cells involve complexes between telomere proteins and TTAGGG DNA repeats. During the differentiation of germ-line cells, telomeres undergo significant reorganization most likely required for additional specific functions in meiosis and fertilization. A telomere-binding protein complex from human sperm (hSTBP) has been isolated by detergent treatment and was partially purified, hSTBP specifically binds double-stranded telomeric DNA and does not contain known somatic telomere proteins TRF1, TRF2, and Ku. Surprisingly, the essential component of this complex has been identified as a specific variant of histone H2B. Indirect immunofluorescence shows punctate localization of H2B in sperm nuclei, which in part coincides with telomeric DNA localization established by fluorescent in situ hybridization. Anti-H2B antibodies block interactions of hSTBP with telomere DNA, and spH2B forms specific complex with this DNA in vitro, indicating that this protein plays a role in telomere DNA recognition. We propose that hSTBP participates in the membrane attachment of telomeres that may be important for ordered chromosome withdrawal after fertilization. C1 Univ Calif Davis, Sch Med, Dept Biol Chem, Davis, CA 95616 USA. Lithuania Acad Sci, Inst Biochem, LT-2001 Vilnius, Lithuania. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Gineitis, AA (reprint author), Univ Calif Davis, Sch Med, Dept Biol Chem, Tupper Hall, Davis, CA 95616 USA. FU NICHD NIH HHS [HD39830-01, R01 HD039830] NR 38 TC 78 Z9 81 U1 1 U2 2 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 1114 FIRST AVE, 4TH FL, NEW YORK, NY 10021 USA SN 0021-9525 J9 J CELL BIOL JI J. Cell Biol. PD DEC 25 PY 2000 VL 151 IS 7 BP 1591 EP 1597 DI 10.1083/jcb.151.7.1591 PG 7 WC Cell Biology SC Cell Biology GA 389KM UT WOS:000166237200021 PM 11134086 ER PT J AU Konechny, A Schwarz, A AF Konechny, A Schwarz, A TI Compactification of M(atrix) theory on noncommutative toroidal orbifolds SO NUCLEAR PHYSICS B LA English DT Article DE M-theory; matrix theory; noncommutative geometry; orbifolds ID PROJECTIVE-MODULES; MORITA EQUIVALENCE; MATRIX MODEL; BPS STATES; TORI; DUALITY AB It was shown by A. Connes, M. Douglas and A. Schwarz that noncommutative tori arise naturally in consideration of toroidal compactifications of M(atrix) theory. A similar analysis of toroidal Z(2) orbifolds leads to the algebra B-theta that can be defined as a crossed product of noncommutative torus and the group Z(2). Our paper is devoted to the study of projective modules over B-theta (Z(2)-equivariant projective modules over a noncommutative torus), We analyze the Morita equivalence (duality) for B-theta algebras working out the two-dimensional case in detail. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Davis, Dept Math, Davis, CA 95616 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Schwarz, A (reprint author), Univ Calif Davis, Dept Math, Davis, CA 95616 USA. NR 26 TC 13 Z9 13 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD DEC 25 PY 2000 VL 591 IS 3 BP 667 EP 684 DI 10.1016/S0550-3213(00)00544-7 PG 18 WC Physics, Particles & Fields SC Physics GA 375XG UT WOS:000165426100004 ER PT J AU Schafer, T AF Schafer, T TI Kaon condensation in high-density quark matter SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLOR-FLAVOR LOCKING; SUPERCONDUCTIVITY; QCD AB We point out that the problem of kaon condensation in dense hadronic matter can be addressed in perturbative QCD. Indeed, perturbative calculations suggest that negative kaons are condensed in high-density quark matter if the presence of electrons is taken into account. This observation sheds new light on the proposal that the low-density hyperon and high-density quark matter phases of QCD are continuously connected. C1 SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Riken BNL Res Ctr, Upton, NY 11973 USA. RP Schafer, T (reprint author), SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. NR 39 TC 57 Z9 60 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 DEC 25 PY 2000 VL 85 IS 26 BP 5531 EP 5534 DI 10.1103/PhysRevLett.85.5531 PN 1 PG 4 WC Physics, Multidisciplinary SC Physics GA 387QD UT WOS:000166132500013 PM 11136039 ER PT J AU Starostin, A Staudenmaier, HM Allgower, CE Bekrenev, V Berger, E Briscoe, WJ Clajus, M Comfort, JR Craig, K Grosnick, D Isenhower, D Knecht, N Koetke, D Koulbardis, A Kozlenko, N Kruglov, S Kycia, T Lolos, G Lopatin, I Manley, DM Manweiler, B Marusic, A McDonald, S Nefkens, BMK Olmsted, J Papandreou, Z Peaslee, D Peterson, RJ Phaisangittisakul, N Prakhov, S Pulver, M Ramirez, AF Sadler, M Shafi, A Slaus, I Spinka, H Stanislaus, S Supek, I Tippens, WB AF Starostin, A Staudenmaier, HM Allgower, CE Bekrenev, V Berger, E Briscoe, WJ Clajus, M Comfort, JR Craig, K Grosnick, D Isenhower, D Knecht, N Koetke, D Koulbardis, A Kozlenko, N Kruglov, S Kycia, T Lolos, G Lopatin, I Manley, DM Manweiler, B Marusic, A McDonald, S Nefkens, BMK Olmsted, J Papandreou, Z Peaslee, D Peterson, RJ Phaisangittisakul, N Prakhov, S Pulver, M Ramirez, AF Sadler, M Shafi, A Slaus, I Spinka, H Stanislaus, S Supek, I Tippens, WB CA Crystal Ball Collaboration TI Measurement of pi(0)pi(0) Production in the nuclear medium by pi(-) Interactions at 0.408 GeV/c SO PHYSICAL REVIEW LETTERS LA English DT Article ID FINITE-TEMPERATURE; SIGMA-MESON; THRESHOLD; PAIRS AB We report on an investigation of the (pi (-), pi (0)pi (0)) reaction by means of measurements of the pi (0)pi (0) invariant mass distributions from pi (-) interactions on H. D, C, Al, and Cu targets at p(pi-) = 0.408 GeV/c. The sharp, strong peak in the pi (+)pi (-) invariant mass near 2m(pi) reported by the CHAOS Collaboration is not seen in our pi (0)pi (0) data. However, we do observe a change in the shape of the pi (0)pi (0) invariant mass spectrum for the different targets, indicating that the pi (0)pi (0) interaction diminishes in the nuclear medium as represented by nuclei D, C, Al, and Cu, compared to hydrogen. C1 Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Karlsruhe, D-76128 Karlsruhe, Germany. Abilene Christian Univ, Abilene, TX 79699 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Arizona State Univ, Tempe, AZ 85287 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Colorado, Boulder, CO 80309 USA. George Washington Univ, Washington, DC 20052 USA. Kent State Univ, Kent, OH 44242 USA. Univ Maryland, College Pk, MD 20742 USA. Petersburg Nucl Phys Inst, Gatchina 188350, Russia. Univ Regina, Regina, SK S4S 0A2, Canada. Rudjer Boskovic Inst, Zagreb 10000, Croatia. Valparaiso Univ, Valparaiso, IN 46383 USA. RP Starostin, A (reprint author), Univ Calif Los Angeles, Los Angeles, CA 90095 USA. NR 21 TC 85 Z9 85 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 25 PY 2000 VL 85 IS 26 BP 5539 EP 5542 DI 10.1103/PhysRevLett.85.5539 PN 1 PG 4 WC Physics, Multidisciplinary SC Physics GA 387QD UT WOS:000166132500015 PM 11136041 ER PT J AU Datz, S Thomas, R Rosen, S Larsson, M Derkatch, AM Hellberg, F van der Zande, W AF Datz, S Thomas, R Rosen, S Larsson, M Derkatch, AM Hellberg, F van der Zande, W TI Dynamics of three-body breakup in dissociative recombination: H2O+ SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUBNANOSECOND TIME RESOLUTION; BRANCHING FRACTIONS; DETECTOR; WATER AB To better understand the propensity for the three-body breakup in dissociative recombination (DR) of dihydrides (H-3(+) NH2+, CH2+, and H2O+), we undertook a study of the dynamics of this process. A study of DR of H2O+ to give O + H + H was carried out at the CRYRING Heavy-ion Storage Ring in Stockholm. With the stored beam energy of 4.5 MeV, we separated the O signal from the H signals with a differential absorber, thus reducing the problem to a sum of two two-body problems. Results included (1) the ratio of O(P-3) to O(D-1) product, (2) the distribution of recoil-kinetic energy between the two hydrogen atoms, (3) the angular distribution between the hydrogen atoms in the O(P-3) channel and in the O(D-1) channel. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. FOM, Inst AMOLF, NL-1098 SJ Amsterdam, Netherlands. Univ Stockholm, Dept Phys, S-11385 Stockholm, Sweden. RP Datz, S (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. RI van der Zande, Wim/D-2506-2009 NR 14 TC 26 Z9 26 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 25 PY 2000 VL 85 IS 26 BP 5555 EP 5558 DI 10.1103/PhysRevLett.85.5555 PN 1 PG 4 WC Physics, Multidisciplinary SC Physics GA 387QD UT WOS:000166132500019 PM 11136045 ER PT J AU Lu, ZY Liu, F Wang, CZ Qin, XR Swartzentruber, BS Lagally, MG Ho, KM AF Lu, ZY Liu, F Wang, CZ Qin, XR Swartzentruber, BS Lagally, MG Ho, KM TI Unique dynamic appearance of a Ge-Si ad-dimer on Si(001) SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SI(100) SURFACE; HOMOEPITAXIAL GROWTH; DIFFUSION; NUCLEATION; BINDING; SILICON; TROUGH; ADATOM AB We carry out a comparative study of the energetics and dynamics of Si-Si, Ge-Ge, and Ge-Si ad-dimers on top of a dimer row in the Si(001) surface, using first-principles calculations. The dynamic appearance of a Ge-Si dimer is distinctively different from that of a Si-Si or Ge-Ge dimer, providing a unique way for its identification by scanning tunneling microscopy (STM). Its "rocking" motion, observed in STM, actually reflects a 180 degrees rotation of the dimer, involving a piecewise-rotation mechanism. The calculated energy barrier of 0.74 eV is in good agreement with the experimental value of 0.82 eV. C1 Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Univ Wisconsin, Madison, WI 53706 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Liu, F (reprint author), Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. RI 上官, 敏慧/E-8964-2012 NR 24 TC 26 Z9 26 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 DEC 25 PY 2000 VL 85 IS 26 BP 5603 EP 5606 DI 10.1103/PhysRevLett.85.5603 PN 1 PG 4 WC Physics, Multidisciplinary SC Physics GA 387QD UT WOS:000166132500031 PM 11136057 ER PT J AU Russina, M Mezei, F Lechner, R Longeville, S Urban, B AF Russina, M Mezei, F Lechner, R Longeville, S Urban, B TI Comment on "Experimental evidence for fast heterogeneous collective stuctural relaxation in a supercooled liquid near the glass transition" - Russina et al. reply SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Hahn Meitner Inst Kernforsch Berlin GmbH, D-14190 Berlin, Germany. RP Russina, M (reprint author), Univ Calif Los Alamos Natl Lab, MS H805, Los Alamos, NM 87545 USA. RI Russina, Margarita/E-9886-2016 OI Russina, Margarita/0000-0003-2067-606X NR 3 TC 1 Z9 1 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 DEC 25 PY 2000 VL 85 IS 26 BP 5670 EP 5670 DI 10.1103/PhysRevLett.85.5670 PN 1 PG 1 WC Physics, Multidisciplinary SC Physics GA 387QD UT WOS:000166132500050 ER PT J AU Wang, XB Nicholas, JB Wang, LS AF Wang, XB Nicholas, JB Wang, LS TI Electronic instability of isolated SO42- and its solvation stabilization SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MULTIPLY-CHARGED ANIONS; PHOTOELECTRON-SPECTROSCOPY; BASIS-SETS; GAS-PHASE; CLUSTERS; WATER; SYSTEMS; IONS; HYDRATION; HYDROGEN AB Despite its ubiquity in nature, SO42- as an isolated dianion has never been detected because of its electronic instability as a result of the two negative charges. This study shows how the first few waters solvate and stabilize an isolated SO42-, molecule-by-molecule, using photodetachment spectroscopy and theoretical calculations. We find that the minimum number of water required to stabilize a free SO42- is three. The first four waters bind tightly to SO42-, each forming two H-bonds with SO42- without inter-water H-bonding. The charges of the dianion are stabilized sufficiently that additional waters form only single H-bonds with SO42- and that inter-water H-bonding is observed starting at n=5. (C) 2000 American Institute of Physics. [S0021-9606(00)01748-7]. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Genentech Inc, San Francisco, CA 94080 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. NR 32 TC 95 Z9 96 U1 0 U2 20 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 22 PY 2000 VL 113 IS 24 BP 10837 EP 10840 AR PII [S0021-9606(00)01748-7] DI 10.1063/1.1333703 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382TZ UT WOS:000165841300002 ER PT J AU Wang, XB Wang, LS AF Wang, XB Wang, LS TI The electronic structure and electron affinities of higher chlorine oxide radicals ClOx (x=2-4) from photoelectron spectroscopy of ClOx- anions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MULTIREFERENCE CONFIGURATION-INTERACTION; MOLECULAR-STRUCTURE; POTENTIAL-ENERGY; AB-INITIO; PHOTODISSOCIATION; DYNAMICS; DIOXIDE; STATES; OZONE; OCIO AB The electronic structure of ClOx (x=2-4) radicals were experimentally investigated using anion photoelectron spectroscopy of the respective anions at several photon energies. The electron affinities of ClO3 and ClO4 were obtained for the first time and were found to be very high, 4.25 +/-0.10 and 5.25 +/-0.10 eV, respectively. Three low-lying excited states were observed for ClO2 with excitation energies of 2.10 eV (B-2(2)), similar to2.60 eV ((2)A(1) and (2)A(2)). The (2)A(1) and (2)A(2) states were found to be nearly degenerate. Two low-lying states were observed for ClO3 at similar to1.20 eV ((2)A(2)) and similar to2.65 eV (E-2), whereas no excited state was observed for ClO4 even at our highest photon energy of 157 nm (7.866 eV). The photoelectron spectra were assigned and compared with available theoretical calculations. The excellent agreement between the experimental and theoretical results confirmed the previous calculations. (C) 2000 American Institute of Physics. [S0021-9606(00)00448-7]. C1 Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, XB (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. NR 52 TC 37 Z9 38 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 22 PY 2000 VL 113 IS 24 BP 10928 EP 10933 AR PII [S0021-9606(00)00448-7] DI 10.1063/1.1326067 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382TZ UT WOS:000165841300011 ER PT J AU Rodriguez, JA Hrbek, J Kuhn, M Jirsak, T Chaturvedi, S Maiti, A AF Rodriguez, JA Hrbek, J Kuhn, M Jirsak, T Chaturvedi, S Maiti, A TI Interaction of sulfur with Pt(111) and Sn/Pt(111): Effects of coverage and metal-metal bonding on reactivity toward sulfur SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; AB-INITIO CALCULATIONS; FIRST-PRINCIPLES; SURFACE ALLOYS; CO ADSORPTION; PROMOTED SULFIDATION; AG/PT(111) SURFACES; BIMETALLIC SURFACES; MOLECULAR-DYNAMICS AB In the chemical and petrochemical industries, Pt-based catalysts are very sensitive to sulfur poisoning. Synchrotron-based high-resolution photoemission, thermal desorption mass spectroscopy (TDS), and first-principles density-functional slab calculations were used to study the adsorption of sulfur on Pt(111) and a p(2x2)-Sn/Pt(111) surface alloy. Our results show important variations in the nature of the bonding of sulfur to Pt(111) depending on the coverage of the adsorbate. For small coverages, theta (S)<0.3 ML, atomic sulfur is the most stable species. The adsorbate is bonded to hollow sites, has a large adsorption energy (> 75 kcal/mol), and desorbs as S. The Pt-S bonds are mainly covalent but sulfur induces a significant decrease in the density of Pt 5d states near the Fermi level. When the sulfur coverage increases on the surface, theta (S)>0.4 ML, there is a substantial weakening in the Pt <---->S interactions with a change in the adsorption site and a tendency to form S-S bonds. Desorption of S-2 is now observed in TDS and the S2p core levels shift to higher binding energy. At coverages near a full monolayer, S-2 is the most stable species on the surface and its adsorption energy is similar to 45 kcal/mol. Similar trends are observed for the adsorption of sulfur on a p(2x2)-Sn/Pt(111) surface alloy, but the adsorbate <----> substrate interactions are weaker than on Pt(111). The formation of Pt-Sn bonds reduces the reactivity of Pt toward sulfur. Electronic effects associated with bimetallic bonding can be useful for controlling or preventing sulfur poisoning. (C) 2000 American Institute of Physics. [S0021-9606(00)70348-5]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Mol Simulat Inc, San Diego, CA 92121 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Hrbek, Jan/I-1020-2013 NR 78 TC 32 Z9 33 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 22 PY 2000 VL 113 IS 24 BP 11284 EP 11292 DI 10.1063/1.1327249 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382TZ UT WOS:000165841300048 ER PT J AU Barrie, LA AF Barrie, LA TI Eurasian air pollution reaches eastern North America - Response SO SCIENCE LA English DT Letter C1 Pacific NW Natl Lab, Atmospher Sci & Global Change Resources & Environ, Richland, WA 99352 USA. RP Barrie, LA (reprint author), Pacific NW Natl Lab, Atmospher Sci & Global Change Resources & Environ, 902 Battelle Blvd, Richland, WA 99352 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 22 PY 2000 VL 290 IS 5500 BP 2259 EP 2259 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 385GQ UT WOS:000165995800019 ER PT J AU Meersmann, T Logan, JW Simonutti, R Caldarelli, S Comotti, A Sozzani, P Kaiser, LG Pines, A AF Meersmann, T Logan, JW Simonutti, R Caldarelli, S Comotti, A Sozzani, P Kaiser, LG Pines, A TI Exploring single-file diffusion in one-dimensional nanochannels by laser-polarized Xe-129 NMR spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR-SIEVE; CHEMICAL-SHIFT; ZEOLITES; SYSTEMS; MODEL AB Single-file diffusion behavior is expected for atoms and molecules in one-dimensional gas phases of nanochannels with transverse dimensions that do not allow for the particles to bypass each other. Although single-file diffusion may play an important role in a wide range of industrial catalytic, geologic, and biological processes, experimental evidence is scarce despite the fact that the dynamics differ substantially from ordinary diffusion. We demonstrate the application of continuous-flow laser-polarized Xe-129 NMR spectroscopy for the study of gas transport into the effectively one-dimensional channels of a microporous material. The novel methodology makes it possible to monitor diffusion over a time scale of tens of seconds, often inaccessible by conventional NMR experiments. The technique can also be applied to systems with very small mobility factors or diffusion constants that are difficult to determine by currently available methods for diffusion measurement. Experiments using xenon in nanochannel systems can distinguish between unidirectional diffusion and single-file diffusion. The experimental observations indicate that single-file behavior for xenon in an organic nanochannel is persistent even at long diffusion times of over tens of seconds. Finally;using continuous flow laser-polarized Xe-129 NMR spectroscopy, we describe an intriguing correlation between the observed NMR line shape of xenon within the nanochannels and the gas transport into these channels. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Milano Bicocca, Dept Mat Sci, I-20125 Milan, Italy. Inst Rech Catalyse, CNRS, F-69626 Villeurbanne, France. Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA. RP Pines, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Caldarelli, Stefano/B-2750-2017 OI Caldarelli, Stefano/0000-0001-9008-9392 NR 22 TC 102 Z9 103 U1 1 U2 18 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 DEC 21 PY 2000 VL 104 IS 50 BP 11665 EP 11670 DI 10.1021/jp002322v PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 383EF UT WOS:000165869600001 ER PT J AU Casson, JL McBranch, DW Robinson, JM Wang, HL Roberts, JB Chiarelli, PA Johal, MS AF Casson, JL McBranch, DW Robinson, JM Wang, HL Roberts, JB Chiarelli, PA Johal, MS TI Reversal of interfacial dipole orientation in polyelectrolyte superlattices due to polycationic layers SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; MULTILAYER FILMS; THIN-FILMS; 2ND-HARMONIC GENERATION; SPECTROSCOPY; ADSORPTION; DEPOSITION; AZOBENZENE; MICROSCOPY; DYE AB Repeated bilayers of a polycation and a polyanion were assembled by adsorption from their aqueous solutions. The polycations used were PEI (poly(ethylenimine)), PAH (poly(allylamine hydrochloride)), and generation 3.0 dendrimer (poly(propylenimine)). The polyanion was PAZO (poly[1-[4-(3-carboxy-4-hydroxyphenylazo)-benzenesulfonamido]-1,2-ethanediyl, sodium salt]). Second harmonic generation (SHG) and UV-vis spectroscopy were used to study the structure and formation of the superlattices. The linear increase in absorbance versus the number of bilayers suggested that a uniform and consistent amount of polymer adsorbed during each deposition cycle. The observation of a second harmonic (SH) signal from the film showed that the conjugated chromophores in the PAZO polymer were aligned with a net dipole. However, the SHG signal did not continue to increase as the number of bilayers was increased. On the basis of thorough studies of the UV and SH properties for each bilayer for 10 total bilayers, we propose that the asymptotic nonlinear optical response is due to loss of charge density on the polycation. The SH signal from multilayers terminated with the polycation is smaller than when PAZO is the terminal layer. We attribute this to a change in orientation of the dipole of the outermost PAZO chromophores at the interface of the PAZO and the terminal polycation layer. We also propose multilayer assemblies that will lead to self-assembled polyelectrolyte superlattices with a high nonlinear optical susceptibility. C1 Univ Calif Los Alamos Natl Lab, Div Chem, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Pomona Coll, Dept Chem, Claremont, CA 91711 USA. RP Johal, MS (reprint author), Univ Calif Los Alamos Natl Lab, Div Chem, POB 1663, Los Alamos, NM 87545 USA. NR 42 TC 31 Z9 31 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 21 PY 2000 VL 104 IS 50 BP 11996 EP 12001 DI 10.1021/jp0029616 PG 6 WC Chemistry, Physical SC Chemistry GA 383EG UT WOS:000165869700024 ER PT J AU Ho, PC Palmer, DA Wood, RH AF Ho, PC Palmer, DA Wood, RH TI Conductivity measurements of dilute aqueous LiOH, NaOH, and KOH solutions to high temperatures and pressures using a flow-through cell SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SODIUM-HYDROXIDE SOLUTIONS; CONDUCTANCE MEASUREMENTS; DIELECTRIC-CONSTANT; ION ASSOCIATION; 300 MPA; WATER; 600-DEGREES-C; ELECTROLYTES AB The limiting molar conductance (Lambda (0)) and molal ion association constant (K-A(m)) of dilute (10(-5) to 10(-3) mol kg(-1)) aqueous LiOH, NaOH, and KOH solutions were determined by a flow-through conductance cell from 50 to 410 degreesC and pressures up to 33 MPa. The flow-through cell is designed to measure molar conductances of dilute aqueous electrolytes with a high degree of accuracy at high temperatures and pressures. The results are complementary to our previously reported results measured with a static high-pressure cell, which was incapable of yielding reliable measurements at concentrations < 0.001 mol.kg(-1) and densities < 0.4 g.cm(-3). The new Lambda (0) values of all three hydroxides at densities (rho) greater than or equal to 0.5 g.cm(-3) are in good agreement with those measured using the static cell. However, at densities below 0.5 g.cm(-3) the new results are slightly higher and less scattered than the previous results at comparable conditions. On the other hand, the K-A(m) values of all three hydroxides are in excellent agreement with the static cell results under analogous conditions. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA. Univ Delaware, Ctr Mol & Engn Thermodynam, Newark, DE 19716 USA. RP Ho, PC (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 23 TC 63 Z9 64 U1 3 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 21 PY 2000 VL 104 IS 50 BP 12084 EP 12089 DI 10.1021/jp000845x PG 6 WC Chemistry, Physical SC Chemistry GA 383EG UT WOS:000165869700035 ER PT J AU Paolucci, P Cavallo, N Fabozzi, F Piccolo, D AF Paolucci, P Cavallo, N Fabozzi, F Piccolo, D TI The IFR online detector control at the BaBar experiment at SLAC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 5th International Workshop on Resistive Plate Chambers and Related Detectors CY OCT 28-29, 1999 CL BARI, ITALY SP Ist Nazl Fis Nucl, Univ Bari, Politecn Bari AB The IFR Online Detector Control (IODC) system and the first results of the detector performances will be described here. The IODC use VxWorks and EPICS to implement slow control data flow of about 3500 channels and to develop part of the readout module. EPICS is interfaced with the BaBar Run Control through the Component Proxy and with the BaBar database (Objectivity) through the Archiver and KeyLookup processes. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Complesso Univ Monte St Angelo, Sez Napoli, Ist Nazl Fis Nucl, I-80126 Naples, Italy. RP Paolucci, P (reprint author), Stanford Linear Accelerator Ctr, POB 20450, Stanford, CA 94309 USA. RI Cavallo, Nicola/F-8913-2012 NR 4 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 21 PY 2000 VL 456 IS 1-2 BP 137 EP 139 DI 10.1016/S0168-9002(00)00978-5 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 388NH UT WOS:000166186800029 ER PT J AU Lisa, MA Ajitanand, NN Alexander, JM Anderson, M Best, D Brady, FP Case, T Caskey, W Cebra, D Chance, JL Chung, P Cole, B Crowe, K Das, AC Draper, JE Gilkes, ML Gushue, S Heffner, M Hirsch, AS Hjort, EL Huo, L Justice, M Kaplan, M Keane, D Kintner, JC Klay, J Krofcheck, D Lacey, RA Lauret, J Liu, H Liu, YM McGrath, R Milosevich, Z Odyniec, G Olson, DL Panitkin, SY Pinkenburg, C Porile, NT Rai, G Ritter, HG Romero, JL Scharenberg, R Schroeder, L Srivastava, B Stone, NTB Symons, TJM Wells, R Whitfield, J Wienold, T Witt, R Wood, L Zhang, WN AF Lisa, MA Ajitanand, NN Alexander, JM Anderson, M Best, D Brady, FP Case, T Caskey, W Cebra, D Chance, JL Chung, P Cole, B Crowe, K Das, AC Draper, JE Gilkes, ML Gushue, S Heffner, M Hirsch, AS Hjort, EL Huo, L Justice, M Kaplan, M Keane, D Kintner, JC Klay, J Krofcheck, D Lacey, RA Lauret, J Liu, H Liu, YM McGrath, R Milosevich, Z Odyniec, G Olson, DL Panitkin, SY Pinkenburg, C Porile, NT Rai, G Ritter, HG Romero, JL Scharenberg, R Schroeder, L Srivastava, B Stone, NTB Symons, TJM Wells, R Whitfield, J Wienold, T Witt, R Wood, L Zhang, WN CA E895 Collaboration TI Azimuthal dependence of pion interferometry at the AGS SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; RELATIVISTIC NUCLEAR COLLISIONS; ANISOTROPIC TRANSVERSE FLOW; BOSE-EINSTEIN CORRELATIONS; TWISS CORRELATION-FUNCTION; ELLIPTIC FLOW; AU+AU COLLISIONS; COLLECTIVE FLOW; HIGH-ENERGIES; TRANSITION AB Two-pion correlation functions, measured as a function of azimuthal emission angle with respect to the reaction plane, provide novel information on the anisotropic shape and orientation of the pion-emitting zone formed in heavy ion collisions. We present the first experimental determination of this information, for semi-central Au + Au collisions at 2-6 A GeV. The source extension perpendicular to the reaction plane is greater than the extension in the plane, and tilt of the pion source in coordinate space is found to be opposite its tilt in momentum space. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Ohio State Univ, Columbus, OH 43210 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Univ Calif Davis, Davis, CA 95616 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Columbia Univ, New York, NY 10027 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Purdue Univ, W Lafayette, IN 47907 USA. Harbin Inst Technol, Harbin 150001, Peoples R China. Kent State Univ, Kent, OH 44242 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. St Marys Coll, Moraga, CA 94575 USA. Univ Auckland, Auckland 1, New Zealand. RP Lisa, MA (reprint author), Ohio State Univ, Columbus, OH 43210 USA. RI Witt, Richard/H-3560-2012 NR 51 TC 47 Z9 47 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD DEC 21 PY 2000 VL 496 IS 1-2 BP 1 EP 8 DI 10.1016/S0370-2693(00)01280-6 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 389FR UT WOS:000166228400001 ER PT J AU Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Devmal, S Fernandez, A Fox, GF Gagnon, P Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lundberg, B Magnin, J MayTal-Beck, S Meadows, B Neto, JRTD Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Simao, FRA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yi, D Yoshida, S Zaliznyak, R Zhang, C AF Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Devmal, S Fernandez, A Fox, GF Gagnon, P Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lundberg, B Magnin, J MayTal-Beck, S Meadows, B Neto, JRTD Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Simao, FRA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yi, D Yoshida, S Zaliznyak, R Zhang, C CA Fermilab E791 Collaboration TI Asymmetries in the production of Lambda(0), Xi(-), and Omega(-) hyperons in 500 GeV/c pi(-)-nucleon interactions SO PHYSICS LETTERS B LA English DT Article ID INTRINSIC CHARM; P INTERACTIONS; GEV-C; D+; POLARIZATION; PARTICLES; MESON; MODEL AB Using data from Fermilab fixed-target experiment E791, we have measured particle-antiparticle production asymmetries for Lambda (0), Xi (-), and Omega (-) hyperons in pi (-) -nucleon interactions at 500 GeV/c. The asymmetries are measured as functions of Feynman-x (x(F)) and p(T)(2) over the ranges -0.12 less than or equal to x(F) less than or equal to 0.12 and 0 less than or equal to p(T)(2) less than or equal to 4 (GeV/c)(2). We find substantial asymmetries, even at x(F) = 0. We also observe leading-particle-type asymmetries which qualitatively agree with theoretical predictions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Mississippi, University, MS 38677 USA. Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. CINVESTAV, Mexico City 14000, DF, Mexico. Fermilab, Batavia, IL 60510 USA. IIT, Chicago, IL 60616 USA. Kansas State Univ, Manhattan, KS 66506 USA. Univ Massachusetts, Amherst, MA 01003 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Autonoma Puebla, Mexico City, DF, Mexico. Univ S Carolina, Columbia, SC 29208 USA. Stanford Univ, Stanford, CA 94305 USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. Tufts Univ, Medford, MA 02155 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06511 USA. RP Aitala, EM (reprint author), Univ Mississippi, University, MS 38677 USA. RI Anjos, Joao/C-8335-2013; Gobel Burlamaqui de Mello, Carla /H-4721-2016 OI Gobel Burlamaqui de Mello, Carla /0000-0003-0523-495X NR 31 TC 14 Z9 15 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 DEC 21 PY 2000 VL 496 IS 1-2 BP 9 EP 18 DI 10.1016/S0370-2693(00)01278-8 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 389FR UT WOS:000166228400002 ER PT J AU Rothenberg, JE AF Rothenberg, JE TI Ultrafast picket fence pulse trains to enhance frequency conversion of shaped inertial confinement fusion laser pulses SO APPLIED OPTICS LA English DT Article ID NATIONAL-IGNITION-FACILITY; GENERATION AB A high-frequency train of 5-100-ps pulses (picket fence) is proposed to improve significantly the third-harmonic frequency conversion of Nd:glass lasers that are used to generate high-contrast-shaped pulses for inertial confinement fusion (ICF) targets. High conversion efficiency of the low-power foot of a shaped ICF pulse is obtained by use of a low duty cycle, multi-gigahertz train of similar to 20-ps pulses with high peak power. Even with less than 10% duty cycle, continuous illumination is maintained on the target by a combination of temporal broadening schemes. The picket fence approach is analyzed, and the practical limits are identified as applied to the National Ignition Facility laser. It is found that the higher conversion efficiency allows similar to 40% more third-harmonic energy to be delivered to the target, potentially enabling the larger drive needed for high-yield ICF target designs. In addition, the frequency conversion efficiency of these short pulses saturates much more readily, which reduces the transfer of fluctuations at the fundamental and thus greatly improves the power stability of the third harmonic. (C) 2000 Optical Society of America OCIS codes: 190.2620, 350.2660, 320.7090, 320.7110, 320.5540. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rothenberg, JE (reprint author), Phaethon Commun, 5005 Brandin Court, Fremont, CA 94538 USA. EM jr@phaethoncommunications.com NR 19 TC 10 Z9 11 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD DEC 20 PY 2000 VL 39 IS 36 BP 6931 EP 6938 DI 10.1364/AO.39.006931 PG 8 WC Optics SC Optics GA 383GG UT WOS:000165874300022 PM 18354706 ER PT J AU Laming, JM Kink, I Takacs, E Porto, JV Gillaspy, JD Silver, EH Schnopper, HW Bandler, SR Brickhouse, NS Murray, SS Barbera, M Bhatia, AK Doschek, GA Madden, N Landis, D Beeman, J Haller, EE AF Laming, JM Kink, I Takacs, E Porto, JV Gillaspy, JD Silver, EH Schnopper, HW Bandler, SR Brickhouse, NS Murray, SS Barbera, M Bhatia, AK Doschek, GA Madden, N Landis, D Beeman, J Haller, EE TI Emission-line intensity ratios in Fe XVII observed with a microcalorimeter on an electron beam ion trap SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; methods : laboratory; stars : individual (Capella); Sun : corona; techniques : spectroscopic; X-rays : general ID X-RAY-SPECTRA; SOLAR-FLARE; ACTIVE-REGION; POLARIZATION; PLASMAS; DENSITY AB We report new observations of emission line intensity ratios of Fe XVII under controlled experimental conditions, using the National Institute of Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. We compare our observations with collisional-radiative models using atomic data computed in distorted wave and R-matrix approximations, which follow the transfer of the polarization of level populations through radiative cascades. Our results for the intensity ratio of the 2p(6) S-1(0)-2p(5)3d P-1(1) 15.014 Angstrom line to the 2p(6) S-1(0)- 2p(5) 3d D-3(1) 15.265 Angstrom line are 2.94 +/- 0.18 and 2.50 +/- 0.13 at beam energies of 900 and 1250 eV, respectively. These results are not consistent with collisional-radiative models and support conclusions from earlier EBIT work at the Lawrence Livermore National Laboratory that the degree of resonance scattering in the solar 15.014 Angstrom line has been overestimated in previous analyses. Further observations assess the intensity ratio of the three lines between the 2p(6)-2p(5)3s configurations to the three lines between the 2p(6)-2p(5)3d configurations. Both R-matrix and distorted wave approximations agree with each other and our experimental results much better than most solar and stellar observations, suggesting that other processes not present in our experiment must play a role in forming the Fe XVII spectrum in solar and astrophysical plasmas. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. MIT, Cambridge, MA 02139 USA. Univ Debrecen, H-4026 Debrecen, Hungary. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Osservatorio Astron GS Vaiana, I-90134 Palermo, Italy. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Laming, JM (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RI Bandler, Simon/A-6258-2010; OI Bandler, Simon/0000-0002-5112-8106; Brickhouse, Nancy/0000-0002-8704-4473 NR 31 TC 71 Z9 72 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 20 PY 2000 VL 545 IS 2 BP L161 EP L164 DI 10.1086/317876 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 393EL UT WOS:000166456200021 ER PT J AU Batista, CD Ortiz, G Balatsky, AV AF Batista, CD Ortiz, G Balatsky, AV TI Common magnetic origin of the resonance peak and incommensuration in high-T-c superconductors SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 3rd International Conference on Stripes and High Tc Superconductivity (STRIPES 2000) CY SEP 25-30, 2000 CL UNIV ROME LA SPIENZA, ROME, ITALY SP Univ Roma La Sapienza, Ist Nazl Fis Materia, CNR, Grp Nazl Struttra Materia HO UNIV ROME LA SPIENZA ID COPPER-OXIDE SUPERCONDUCTORS; NEUTRON-SCATTERING; SPIN DYNAMICS; YBA2CU3O6+X; EXCITATIONS; DEPENDENCE; BILAYER AB We present a unified theory for the resonance peak and low-energy incommensurate response observed in high-T-c cuprate superconductors. The origin of both features is purely magnetic and they represent universal features signaling the existence of an incommensurate spin state both below and above the superconducting transition temperature. We argue that the resonance peak is the reflection of commensurate antiferromagnetism. Our theoretical scenario gives an account of the main universal features observed in various families of superconductors and predicts those that have not been observed yet experimentally. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Batista, CD (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. RI Batista, Cristian/J-8008-2016 NR 33 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 2000 VL 14 IS 29-31 BP 3334 EP 3341 DI 10.1142/S0217979200003587 PG 8 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 394CW UT WOS:000166507300009 ER PT J AU Martin, I Ortiz, G Balatsky, AV Bishop, AR AF Martin, I Ortiz, G Balatsky, AV Bishop, AR TI Competing quantum orderings in cuprate superconductors: A minimal model SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 3rd International Conference on Stripes and High Tc Superconductivity (STRIPES 2000) CY SEP 25-30, 2000 CL UNIV ROME LA SPIENZA, ROME, ITALY SP Univ Roma La Sapienza, Ist Nazl Fis Materia, CNR, Grp Nazl Struttra Materia HO UNIV ROME LA SPIENZA AB We present a minimal model for cuprate superconductors. At the unrestricted mean-field level, the model produces homogeneous superconductivity at large doping, striped superconductivity in the underdoped regime and various antiferromagnetic phases at low doping and for high temperatures. On the underdoped side, the superconductor is intrinsically inhomogeneous and global phase coherence is achieved through Josephson-like coupling of the superconducting stripes. The model is applied to calculate experimentally measurable ARPES spectra. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Martin, I (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 20 TC 44 Z9 44 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 2000 VL 14 IS 29-31 BP 3567 EP 3576 DI 10.1142/S0217979200003630 PG 10 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 394CW UT WOS:000166507300044 ER PT J AU Mesot, J Kaminski, A Fretwell, HM Rosenkranz, S Campuzano, JC Norman, MR Ding, H Randeria, M Kadowaki, K AF Mesot, J Kaminski, A Fretwell, HM Rosenkranz, S Campuzano, JC Norman, MR Ding, H Randeria, M Kadowaki, K TI Proximity of the metal-insulator/magnetic transition and its impact on the one-electron spectral function: A doping-dependent ARPES study SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 3rd International Conference on Stripes and High Tc Superconductivity (STRIPES 2000) CY SEP 25-30, 2000 CL UNIV ROME LA SPIENZA, ROME, ITALY SP Univ Roma La Sapienza, Ist Nazl Fis Materia, CNR, Grp Nazl Struttura Mat HO UNIV ROME LA SPIENZA ID HIGH-TEMPERATURE SUPERCONDUCTORS; NEUTRON-SCATTERING; FERMI-SURFACE; QUASI-PARTICLES; BI2SR2CACU2O8+DELTA; STATE; EXCITATIONS; DISPERSION; EVOLUTION; BILAYER AB The doping dependence of the low-temperature spectral function is precisely determined from angle resolved photoemission (ARPES) measurements. It is found that, as the doping decreases, the maximum of the superconducting gap increases, but the slope of the gap near the nodes decreases. Though consistent with d-wave symmetry, the gap with underdoping cannot be fit by the simple cos(k(x)) - cos(k(y)) form. We suggest that this arises due to the increasing importance of long range interactions as one approaches the insulator. It is also shown that the shape of the spectral function at the (pi, 0) point below T(c) can be explained by the interaction of the electrons with a collective mode whose energy matches that of the magnetic resonance as obtained by inelastic neutron scattering data, and points to the intimate relation of magnetic correlations to high T(c) superconductivity. C1 Univ Illinois, Dept Phys, Chicago, IL 60607 USA. Swiss Fed Inst Technol, Neutron Scattering Lab, CH-5232 Villigen, Switzerland. PSI Villigen, CH-5232 Villigen, Switzerland. Univ Coll Swansea, Dept Phys, Swansea, W Glam, Wales. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Univ Tsukuba, Inst Sci Mat, Tsukuba, Ibaraki 305, Japan. RP Mesot, J (reprint author), Univ Illinois, Dept Phys, Chicago, IL 60607 USA. RI Rosenkranz, Stephan/E-4672-2011; Norman, Michael/C-3644-2013; OI Rosenkranz, Stephan/0000-0002-5659-0383; Ding, Hong/0000-0003-4422-9248 NR 25 TC 1 Z9 1 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 2000 VL 14 IS 29-31 BP 3596 EP 3601 DI 10.1142/S0217979200004118 PG 6 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 394CW UT WOS:000166507300048 ER PT J AU Mizokawa, T Ino, A Yoshida, T Fujimori, A Kim, C Eisaki, H Shen, ZX Horii, S Kakeshita, T Uchida, S Tomimoto, K Tajima, S Yamada, Y AF Mizokawa, T Ino, A Yoshida, T Fujimori, A Kim, C Eisaki, H Shen, ZX Horii, S Kakeshita, T Uchida, S Tomimoto, K Tajima, S Yamada, Y TI ARPES study of LSCO and PBCO: Electronic structure of the stripe phase and the 1/4-filled Cu-O chains SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 3rd International Conference on Stripes and High Tc Superconductivity (STRIPES 2000) CY SEP 25-30, 2000 CL UNIV ROME LA SPIENZA, ROME, ITALY SP Univ Roma La Sapienza, Ist Nazl Fis Materia, CNR, Grp Nazl Struttra Materia HO UNIV ROME LA SPIENZA ID UNTWINNED PRBA2CU3O7; SPECTRAL PROPERTIES; NORMAL-STATE; PLANE; LA2-XSRXCUO4; TEMPERATURE; MODEL; GAP; BI2SR2CACU2O8+DELTA; SUPERCONDUCTIVITY AB We have studied the electronic structure of the stripe phase in La2-xSrxCuO4 (LSCO) and the Cu-O chains in PrBa2Cu3O7 (Pr123) and PrBa2Cu4O8 (Pr124) using angle-resolved photoemission spectroscopy (ARPES). In LSCO with x = 0.12, the spectral feature near the Fermi level (E-F) is almost flat from (pi; 0) to (pi, pi /4), namely, along the stripe direction in LSCO. While the 1/4-filled chain in Pr123 has a band gap because of charge ordering, the metallic chain in Pr124 shows a dispersive feature which reaches E-F at similar to (pi, pi /4) and a flat feature near E-F which is similar to that observed in the stripe phase of LSCO. Although Pr124 shows spectral-weight suppression near E-F due to the instability toward charge ordering, the suppression is imperfect and Pr124 has a substantial spectral weight at E-F probably due to the chain-chain coupling. This is in sharp contrast to LSCO with the perfect gap opening near (pi; pi /4). The difference between the stripe phase in LSCO and the coupled chains of Pr124 would be derived from the interaction between the stripe and the neighboring Cu spins which suppresses the charge ordering along the stripe. C1 Univ Tokyo, Dept Complex Sci & Engn, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Univ Tokyo, Dept Adv Mat, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Dept Superconduct, Bunkyo Ku, Tokyo 1130033, Japan. Int Superconduct Technol Ctr, Koto Ku, Tokyo 1350062, Japan. Shimane Univ, Fac Sci & Engn, Matsue, Shimane 6900823, Japan. RP Mizokawa, T (reprint author), Univ Tokyo, Dept Complex Sci & Engn, Bunkyo Ku, Tokyo 1130033, Japan. RI Mizokawa, Takashi/E-3302-2015 OI Mizokawa, Takashi/0000-0002-7682-2348 NR 36 TC 0 Z9 0 U1 0 U2 3 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 2000 VL 14 IS 29-31 BP 3602 EP 3609 DI 10.1142/S021797920000412X PG 8 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 394CW UT WOS:000166507300049 ER PT J AU Vasiliu-Doloc, L Osborn, R Rosenkranz, S Mesot, J Mitchell, JF Sinha, SK Seeck, OH Lynn, JW Islam, Z AF Vasiliu-Doloc, L Osborn, R Rosenkranz, S Mesot, J Mitchell, JF Sinha, SK Seeck, OH Lynn, JW Islam, Z TI Polaron ordering in ferromagnetic colossal magnetoresistive oxides SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 3rd International Conference on Stripes and High Tc Superconductivity (STRIPES 2000) CY SEP 25-30, 2000 CL UNIV ROME LA SPIENZA, ROME, ITALY SP Univ Roma La Sapienza, Ist Nazl Fis Materia, CNR, Grp Nazl Struttra Materia HO UNIV ROME LA SPIENZA ID X-RAY-SCATTERING; NEUTRON-SCATTERING; CHARGE; LA1.2SR1.8MN2O7; LA1-XSRXMNO3; MANGANITES; TRANSITION; DISTORTION; COLLAPSE; STRIPES AB We review our recent x-ray and neutron scattering studies that reveal static diffuse scattering due to polarons in the paramagnetic phase of the colossal magnetoresistive manganites La2-2xSr1+2x,Mn2O7, with x = 0.40 and 0.44. We show that the polarons exhibit short-range incommensurate correlations that grow with decreasing temperature, but disappear abruptly at the combined ferromagnetic and metal-insulator transition in the x = 0.40 system because of the sudden charge delocalization, while persisting at low temperature in the antiferromagnetic x = 0.44 system. The "melting" of the polaron ordering as we cool through Te occurs with the collapse of the polaron scattering itself in the x = 0.40 system. The polaron order is characterized by an ordering wave vector q = (0.3,0,1) that is almost independent of x for x greater than or equal to 0.40, and is consistent with a model of disordered stripes. C1 No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Vasiliu-Doloc, L (reprint author), No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. RI Rosenkranz, Stephan/E-4672-2011; Osborn, Raymond/E-8676-2011 OI Rosenkranz, Stephan/0000-0002-5659-0383; Osborn, Raymond/0000-0001-9565-3140 NR 24 TC 1 Z9 1 U1 0 U2 3 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 2000 VL 14 IS 29-31 BP 3711 EP 3718 DI 10.1142/S021797920000426X PG 8 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 394CW UT WOS:000166507300066 ER PT J AU Yoshida, T Nakamura, M Ino, A Mizokawa, T Fujimori, A Zhou, XJ Kellar, SA Bogdanov, PV Lu, ED Lanzara, A Eisaki, H Hussain, Z Shen, ZX Kakeshita, T Uchida, S AF Yoshida, T Nakamura, M Ino, A Mizokawa, T Fujimori, A Zhou, XJ Kellar, SA Bogdanov, PV Lu, ED Lanzara, A Eisaki, H Hussain, Z Shen, ZX Kakeshita, T Uchida, S TI Nodal spectral weight and Fermi surface in La2-xSrxCuO4 SO INTERNATIONAL JOURNAL OF MODERN PHYSICS B LA English DT Article; Proceedings Paper CT 3rd International Conference on Stripes and High Tc Superconductivity (STRIPES 2000) CY SEP 25-30, 2000 CL UNIV ROME LA SPIENZA, ROME, ITALY SP Univ Roma La Sapienza, Ist Nazl Fis Materia, CNR, Grp Nazl Struttra Materia HO UNIV ROME LA SPIENZA ID ELECTRONIC-STRUCTURE; OXIDE SUPERCONDUCTORS; BI2SR2CACU2O8+DELTA; TEMPERATURE; TRANSITION; PHASE; BAND AB We present spectral weight mapping in the momentum space for La2-chiSrchiCuO4 using angle-resolved photoemission spectroscopy. The spectral weight of the nodal states, which shows suppression in previous results, is enhanced and shows sharp peaks in the second Brillouin zone for the overdoped sample due to matrix element effects, although they remain much weaker than the other cuprates. C1 Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. Nara Univ Educ, Dept Phys, Takabatake, Nara 6308523, Japan. Japan Atom Energy Res Inst, SPring8, Sayo, Hyogo 6795198, Japan. Univ Tokyo, Dept Complex Sci & Engn, Bunkyo Ku, Tokyo 1130033, Japan. Stanford Univ, Dept Appl Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Tokyo, Dept Superconduct, Bunkyo Ku, Tokyo 1138656, Japan. Univ Tokyo, Dept Adv Mat Sci, Bunkyo Ku, Tokyo 1130033, Japan. RP Yoshida, T (reprint author), Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. RI Mizokawa, Takashi/E-3302-2015 OI Mizokawa, Takashi/0000-0002-7682-2348 NR 21 TC 0 Z9 0 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9792 J9 INT J MOD PHYS B JI Int. J. Mod. Phys. B PD DEC 20 PY 2000 VL 14 IS 29-31 BP 3777 EP 3782 DI 10.1142/S0217979200004349 PG 6 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 394CW UT WOS:000166507300075 ER PT J AU Haw, JF Zhang, JH Shimizu, K Venkatraman, TN Luigi, DP Song, WG Barich, DH Nicholas, JB AF Haw, JF Zhang, JH Shimizu, K Venkatraman, TN Luigi, DP Song, WG Barich, DH Nicholas, JB TI NMR and theoretical study of acidity probes on sulfated zirconia catalysts SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SOLID-STATE NMR; IN-SITU NMR; BUTANE ISOMERIZATION; AB-INITIO; ZEOLITE; TRIMETHYLPHOSPHINE; STRENGTH; ALKANES; SUPERACIDITY; ADSORPTION AB The measurement of the type and number of acid sites on sulfated zirconia catalysts using the P-31 NMR spectrum of adsorbed P(CH3)(3) has been vexed by spectral assignment controversies. Using a combination of NMR experiments and theoretical methods, including chemical shift calculations at the GIAO-MP2 level. we show that a previously observed P-31 resonance at +27 ppm is due to P(CH3)(4)(+), formed in a reaction that consumes a Bronsted site. The coproduct of this reaction. PH(CH3)(2), is protonated on the surface to yield a P-31 resonance in the region expected for P(CH3)(3) On a Lewis site. Further complications result from a signal due to OP(CH3)(3), formed by oxidizing sites on the surface, complexed to unidentified acid sites. As an alternative, we show that carefully designed N-15 experiments using the less reactive and less basic probe pyridine-N-15 provide more easily interpreted measurements of Bronsted and Lewis sites on sulfated zirconias of diverse composition, preparation, and treatment. Quantitative studies revealed that the number of Bronsted sites capable of protonating pyridine corresponded to only similar to7% of the sulfur atoms on the catalyst we studied in the greatest depth. Additional Bronsted sites were created on this catalyst with addition of water, a reaction not observed for sulfur-free zirconia. C1 Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. RP Haw, JF (reprint author), Univ So Calif, Loker Hydrocarbon Res Inst, Univ Pk, Los Angeles, CA 90089 USA. RI Song, Weiguo/D-6041-2016; OI Song, Weiguo/0000-0001-5390-6787; Shimizu, Ken/0000-0002-0229-6541 NR 48 TC 83 Z9 86 U1 4 U2 27 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 DEC 20 PY 2000 VL 122 IS 50 BP 12561 EP 12570 DI 10.1021/ja0027721 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA 387ZZ UT WOS:000166154100018 ER PT J AU Bullock, RM Voges, MH AF Bullock, RM Voges, MH TI Homogeneous catalysis with inexpensive metals: Ionic hydrogenation of ketones with molybdenum and tungsten catalysts SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ASYMMETRIC TRANSFER HYDROGENATION; HYDRIDE TRANSFER-REACTIONS; STRUCTURAL CHARACTERIZATION; COORDINATED DIHYDROGEN; COMPLEXES; RUTHENIUM; ALDEHYDES; DIHYDRIDE; CHEMISTRY; PROTON C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Bullock, RM (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Bullock, R. Morris/L-6802-2016 OI Bullock, R. Morris/0000-0001-6306-4851 NR 31 TC 95 Z9 95 U1 3 U2 22 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 DEC 20 PY 2000 VL 122 IS 50 BP 12594 EP 12595 DI 10.1021/ja0010599 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 387ZZ UT WOS:000166154100026 ER PT J AU Sorensen, KJ Zetterberg, LA Nelson, DO Grawe, J Tucker, JD AF Sorensen, KJ Zetterberg, LA Nelson, DO Grawe, J Tucker, JD TI The in vivo dose rate effect of chronic gamma radiation in mice: translocation and micronucleus analyses SO MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS LA English DT Article DE mice; ionizing radiation; in vivo; translocations; micronuclei ID FLOW CYTOMETRIC ANALYSIS; PERIPHERAL-BLOOD; POLYCHROMATIC ERYTHROCYTES; CHROMOSOME-ABERRATIONS; MOUSE ERYTHROCYTES; INDUCTION; EXPOSURE; WORKERS; PROBES AB The in vivo effects of chronic, ultra low dose rates of gamma radiation in mice were evaluated using fluorescence in situ hybridization and the in vivo micronucleus test. SWR x C57BL/6 mice were divided into nine exposure groups and continuously exposed to 0.5, 2.0 or 4.0 cGy Cs-137 per day for 30, 60 or 90 days; unexposed control mice were also included. Following exposure, blood samples were taken from each animal and the frequencies of micronucleated polychromatic erythrocytes (MPCE) and micronucleated normochromatic erythrocytes (MNCE) were determined using flow cytometry. Peripheral blood lymphocytes were cultured and analyzed by chromosome painting to determine translocation frequencies. A significant dose rate response was seen in translocations and both MPCE and MNCE. Comparisons were made between the three chronic dose rates and it was determined that there was no significant difference among translocation frequencies for each rate. However, a significant difference was found between the chronic exposures reported here and the fractionated daily exposures reported previously. Dose rate reduction effects, ranging from 3 at low doses to 14 at high doses, were found for chronic versus acute exposures. The possibility of gender effects was investigated in both micronucleus and translocation data. No gender effect was found in translocation induction, but a slight effect was suggested in micronucleus induction. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Uppsala Univ, Dept Conservat Biol & Genet, SE-75007 Uppsala, Sweden. Univ Stockholm, Wallenberg Lab, Dept Genet & Cellular Toxicol, SE-10691 Stockholm, Sweden. RP Tucker, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-448,POB 808, Livermore, CA 94551 USA. NR 33 TC 24 Z9 27 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0027-5107 J9 MUTAT RES-FUND MOL M JI Mutat. Res.-Fundam. Mol. Mech. Mutagen. PD DEC 20 PY 2000 VL 457 IS 1-2 BP 125 EP 136 DI 10.1016/S0027-5107(00)00136-6 PG 12 WC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology SC Biotechnology & Applied Microbiology; Genetics & Heredity; Toxicology GA 385CB UT WOS:000165983100011 PM 11106804 ER PT J AU Plass, R Kellogg, GL AF Plass, R Kellogg, GL TI Surface morphology changes during Pb deposition on Cu(100): evidence for surface alloyed Cu(100)-c(2 x 2) Pb SO SURFACE SCIENCE LA English DT Article DE low-energy electron microscopy (LEEM); growth; nucleation; surface relaxation and reconstruction; copper; lead; low index single crystal surfaces ID STEPPED COPPER SURFACES; LOW-INDEX; LEAD; ADSORPTION; SCATTERING; OVERLAYERS; MONOLAYER; PHASE; LEED AB Using low energy electron microscopy (LEEM), we have followed Cu(1 0 0) surface morphology changes during Pb deposition at different temperatures. Surface steps advance and two-dimensional (2-D) islands nucleate and grow as deposited Pb first alloys, and then dealloys, on a 125 degreesC Cu(1 0 0) surface. From LEEM images, we determine how much Cu is being displaced at each stage and find that the amount of material added to the top layer for a complete Pb/Cu(1 0 0) c(4 x 4) reconstruction (a surface alloy) is consistent with the expected c(4 x 4) Cu content of 0.5 monolayer. However, as the surface changes to the Pb/Cu(1 0 0) c(2 x 2) overlayer, we find that the displaced material from surface dealloying, 0.22 ML, is more than a factor of two lower than expected based on a pure Pb c(2 x 2) overlayer. Further, we find that in the 70-130 degreesC range the amount of Cu remaining in c(2 x 2) increases with increasing substrate temperature during the deposition, showing that surface Cu is alloyed with Pb in the c(2 x 2) structure at these temperatures. When holding the sample at 125 degreesC, the transformation from the c(2 x 2) structure to the higher coverage c(5 root2 x root2)R45 degrees overlayer structure displaces more Cu, confirming the c(2 x 2) surface alloy model. We also find the c(2 x 2) surface has characteristically square 2-D islands with step edges parallel to the (1 0 0) type crystallographic directions, whereas the c(5 root2 x root2)R45 degrees structure has line-like features which run parallel to the dislocation double rows of this surface's atomic structure and which expand into 2-D islands upon coarsening. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Plass, R (reprint author), Sandia Natl Labs, POB 5800,Mail Stop 1415, Albuquerque, NM 87185 USA. NR 19 TC 16 Z9 16 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD DEC 20 PY 2000 VL 470 IS 1-2 BP 106 EP 120 DI 10.1016/S0039-6028(00)00846-3 PG 15 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 397YU UT WOS:000166727100030 ER PT J AU Sohlberg, K Pantelides, ST Pennycook, SJ AF Sohlberg, K Pantelides, ST Pennycook, SJ TI Theoretical proposal: a tunable heterogeneous catalyst SO SURFACE SCIENCE LA English DT Letter DE density functional calculations; catalysis; surface relaxation and reconstruction; aluminum oxide ID MOLECULAR-DYNAMICS SIMULATIONS; GAMMA-ALUMINA SURFACES; TRANSITION ALUMINAS; LEWIS ACIDITY; GAMMA-AL2O3; MODEL; PSEUDOPOTENTIALS; ENERGY; SITES; ATOMS AB First principle calculations predict that the massive surface reconstruction of cubic alumina can be switched on or off by controlling the bulk Ii content and temperature. In one state the surface contains highly valence unsaturated Al atoms, the sourer of surface acidity central to catalysis. In the other state, these Al atoms bury themselves below the surface, giving a weaker surface acidity and a softer catalyst. These results evince a surface catalytic activity of alumina that can be tuned by switching between these two modes, opening the way for tunable heterogeneous catalysis. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RP Sohlberg, K (reprint author), Drexel Univ, Dept Chem, 3141 Chestnut St, Philadelphia, PA 19104 USA. NR 26 TC 5 Z9 5 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD DEC 20 PY 2000 VL 470 IS 1-2 BP L88 EP L92 DI 10.1016/S0039-6028(00)00915-8 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 397YU UT WOS:000166727100015 ER PT J AU Stevens, FJ Pokkuluri, PR Schiffer, M AF Stevens, FJ Pokkuluri, PR Schiffer, M TI Protein conformation and disease: Pathological consequences of analogous mutations in homologous proteins SO BIOCHEMISTRY LA English DT Article ID MARIE-TOOTH-DISEASE; MYELIN PO GENE; IMMUNOGLOBULIN LIGHT-CHAINS; TYROSINE-PHOSPHATASE SHP-2; NEUROPATHY TYPE-III; DE-NOVO MUTATION; ZERO MPZ GENE; DEJERINE-SOTTAS; PERIPHERAL NEUROPATHIES; INHERITED NEUROPATHIES AB The antibody light chain variable domain (V-L)(1) and myelin protein zero (MPZ) are representatives of the functionally diverse immunoglobulin superfamily. The V-L is a subunit Of the antigen-binding component of antibodies, while MPZ is the major membrane-linked constituent of the myelin sheaths that coat peripheral nerves. Despite limited amino acid sequence homology, the conformations of the core structures of the two proteins are largely superimposable. Amino acid variations in V-L account for various conformational disease outcomes, including amyloidosis. However, the specific amino acid changes in V-L that are responsible for disease have been obscured by multiple concurrent primary structure alterations. Recently, certain demyelination disorders have been linked to point mutations and single amino acid polymorphisms in MPZ. We demonstrate here that some pathogenic variations in MPZ correspond to changes suspected of determining amyloidosis in V-L. This unanticipated observation suggests that studies of the biophysical origin of conformational disease in one member of a superfamily of homologous proteins may have implications throughout the superfamily. In some cases, findings may account for overt disease; in other cases, due to the natural repertoire of inherited polymorphisms, variations in a representative protein may predict subclinical impairment of homologous proteins. C1 Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Stevens, FJ (reprint author), Argonne Natl Lab, Biosci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. FU NIA NIH HHS [AG18001]; NIDDK NIH HHS [DK43757] NR 78 TC 12 Z9 13 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD DEC 19 PY 2000 VL 39 IS 50 BP 15291 EP 15296 DI 10.1021/bi001017x PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 383GV UT WOS:000165875500001 PM 11112514 ER PT J AU Makkar, R Whiting, J Li, A Honda, H Fishbein, MC Knapp, FF Hausleiter, J Litvack, F Eigler, NL AF Makkar, R Whiting, J Li, A Honda, H Fishbein, MC Knapp, FF Hausleiter, J Litvack, F Eigler, NL TI Effects of beta(-)-emitting Re-188 balloon in stented porcine coronary arteries - An angiographic, intravascular ultrasound, and histomorphometric study SO CIRCULATION LA English DT Article DE balloon; restenosis; angioplasty; stents ID INHIBITS NEOINTIMA FORMATION; INTRACORONARY RADIATION; RESTENOSIS; PREVENTION; IRRADIATION; SWINE AB Background-Restenosis within stents may be prevented by ionizing radiation from an intravascular source. Methods and Results-A liquid beta (-) radiation (Re-188) balloon was evaluated in a randomized and blinded porcine coronary model of stent restenosis. Group A pigs (n=17) received 0,16, 22, or 29 Gy at 0.5-mm depth, followed by stenting. Restenosis was quantified by angiography, ultrasound, and histomorphometry at 30 days. Group B (n=7) was stented first and then treated with 0 or 29 Gy with follow-up at 60 days. There was a measurable effect at 16 Gy, which improved with increasing doses. At 29 Gy, the histological stenotic area was reduced by 67% (22% versus 66% in controls, P<0.001). Radiation after stenting was equally effective; the stenotic area was reduced (21% versus 65%, P<0.001). At 16 Gy, the vessel just distal to the stent was significantly smaller than control vessels because of intimal thickening (P=0.003). Radiated vessels had distinctive histology consisting of neointimal fibrin and reduced smooth muscle cells and matrix (P<0.0001). Conclusions-Re-188 balloon brachytherapy in porcine coronary arteries results in dose-dependent and injury-independent inhibition of stent restenosis for up to 60 days. Restenosis at the borders of the irradiated zone is a potential limitation and may be related to underdosing. Brachytherapy with the Re-188 balloon appears to be safe and feasible for clinical studies. C1 Cedars Sinai Med Ctr, Div Cardiol, Los Angeles, CA 90048 USA. Cedars Sinai Med Ctr, Res Inst, Los Angeles, CA 90048 USA. Univ Calif Los Angeles, Sch Med, Dept Pathol, Los Angeles, CA 90024 USA. Cedars Sinai Med Ctr, Div Med Phys, Los Angeles, CA 90048 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Eigler, NL (reprint author), Cedars Sinai Med Ctr, Div Cardiol, 8700 Beverly Blvd, Los Angeles, CA 90048 USA. NR 14 TC 15 Z9 18 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD DEC 19 PY 2000 VL 102 IS 25 BP 3117 EP 3123 PG 7 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 384EU UT WOS:000165930500024 PM 11120704 ER PT J AU Du, XL Choi, IG Kim, R Wang, WR Jancarik, J Yokota, H Kim, SH AF Du, XL Choi, IG Kim, R Wang, WR Jancarik, J Yokota, H Kim, SH TI Crystal structure of an intracellular protease from Pyrococcus horikoshii at 2-angstrom resolution SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ESCHERICHIA-COLI; PROTEOLYTIC ACTIVITY; 20S PROTEASOME; FURIOSUS; PROTEINS; MAD; CRYSTALLOGRAPHY; RECOGNITION; EXPRESSION; HYDROLASE AB The intracellular protease from Pyrococcus horikoshii (PH1704) and PfpI from Pyrococcus furiosus are members of a class of intracellular proteases that have no sequence homology to any other known protease family. We report the crystal structure of PH1704 at 2.0-Angstrom resolution. The protease is tentatively identified as a cysteine protease based on the presence of cysteine (residue 100) in a nucleophile elbow motif. In the crystal, PH1704 forms a hexameric: ring structure, and the active sites are formed at the interfaces between three pairs of monomers. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Biol Struct, Phys Biosci Div, Berkeley, CA 94720 USA. RP Kim, SH (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Choi, In-Geol/F-3152-2013 NR 31 TC 79 Z9 82 U1 0 U2 3 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD DEC 19 PY 2000 VL 97 IS 26 BP 14079 EP 14084 DI 10.1073/pnas.260503597 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 385FV UT WOS:000165993700019 PM 11114201 ER PT J AU Chemla, YR Crossman, HL Poon, Y McDermott, R Stevens, R Alper, MD Clarke, J AF Chemla, YR Crossman, HL Poon, Y McDermott, R Stevens, R Alper, MD Clarke, J TI Ultrasensitive magnetic biosensor for homogeneous immunoassay SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID SACCHAROMYCES-CEREVISIAE; MAGNETOTACTIC BACTERIA; MICROSCOPE AB A technique is described for specific, sensitive, quantitative, and rapid detection of biological targets by using superparamagnetic nanoparticles and a "microscope" based on a high-transition temperature de superconducting quantum interference device (SQUID). In this technique, a mylar film to which the targets have been bound is placed on the microscope. The firm, at room temperature and atmospheric pressure, is typically 40 mum from the SQUID, which is at 77 K in a vacuum. A suspension of magnetic nanoparticles carrying antibodies directed against the target is added to the mixture in the well, and 1-s pulses of magnetic field are applied parallel to the SQUID. In the presence of this aligning field the nanoparticles develop a net magnetization, which relaxes when the field is turned off. Unbound nanoparticles relax rapidly by Brownian rotation and contribute no measurable signal. Nanoparticles that are hound to the target on the film are immobilized and undergo Neel relaxation, producing a slowly decaying magnetic flux, which is detected by the SQUID. The ability to distinguish between bound and unbound labels allows one to run homogeneous assays, which do not require separation and removal of unbound magnetic particles. The technique has been demonstrated with a model system of liposomes carrying the FLAG epitope. The SQUID microscope requires no more than (5 +/- 2) x 10(4) magnetic nanoparticles to register a reproducible signal. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Scripps Res Inst, La Jolla, CA 92037 USA. RP Univ Calif Berkeley, Dept Phys, 366 LeConte Hall 7300, Berkeley, CA 94720 USA. EM jclarke@physics.berkeley.edu RI Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 NR 14 TC 303 Z9 310 U1 7 U2 61 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD DEC 19 PY 2000 VL 97 IS 26 BP 14268 EP 14272 DI 10.1073/pnas.97.26.14268 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 385FV UT WOS:000165993700052 PM 11121032 ER PT J AU Wang, W Mariani, FV Harland, RM Luo, KX AF Wang, W Mariani, FV Harland, RM Luo, KX TI Ski represses bone morphogenic protein signaling in Xenopus and mammalian cells SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID PROTOONCOGENE C-SKI; HOMEOBOX GENE; MUSCLE DIFFERENTIATION; SMAD PROTEINS; EXPRESSION; ONCOPROTEIN; ONCOGENE; EMBRYOS; PATHWAY; CONVERTS AB The bone morphogenic proteins (BMPs) play important roles in vertebrate development. In Xenopus, BMPs act as epidermal inducers and also as negative regulators of neurogenesis. Antagonism of BMP signaling results in neuralization. BMPs signal through the cell-surface receptors and downstream Smad molecules. Upon stimulation with BMP, Smad1, Smad5. and Smad8 are phosphorylated by the activated BMP receptors, form a complex with Smad4, and translocate into the nucleus, where they regulate the expression of BMP target genes. Here, we show that the Ski oncoprotein can block BMP signaling and the expression of BMP-responsive genes in both Xenopus and mammalian cells by directly interacting with and repressing the activity of BMP-specific Smad complexes. This ability to antagonize BMP signaling results in neuralization by Ski in the Xenopus embryo and blocking of osteoblast differentiation of murine W-20-17 cells. Thus, Ski is able to repress the activity of all receptor-associated Smads and may regulate vertebrate development by modulating the signaling activity of transforming growth factor-beta family members. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. RP Luo, KX (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM49346, R01 GM049346] NR 37 TC 90 Z9 98 U1 0 U2 0 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD DEC 19 PY 2000 VL 97 IS 26 BP 14394 EP 14399 DI 10.1073/pnas.97.26.14394 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 385FV UT WOS:000165993700074 PM 11121043 ER PT J AU Ishimaru, M Hirotsu, Y Li, FX Sickafus, KE AF Ishimaru, M Hirotsu, Y Li, FX Sickafus, KE TI Surface morphology of ion-beam-irradiated rutile single crystals SO APPLIED PHYSICS LETTERS LA English DT Article ID IMPLANTED SILICON; LATTICE DISORDER; LOCATION; TIO2 AB Ion-beam-induced structural changes in rutile (TiO2) have been examined in detail using transmission electron microscopy (TEM). Single crystals of rutile with (100) orientation were irradiated with 360 keV Xe ions at room temperature to a fluence of 4x10(15)/cm(2). In addition to a buried damage layer induced by projectile ions, a damage layer was formed near the surface (thickness about 10 nm). Nanobeam electron diffraction measurements and high-resolution TEM observations revealed that the surface damage layer consists of rutile crystallites with different orientations compared to the original single crystal. We discuss damage recovery processes in ion irradiated rutile within the context of our results as well as previous observations. (C) 2000 American Institute of Physics. [S0003-6951(01)01401-2]. C1 Osaka Univ, Inst Sci & Ind Res, Osaka 5670047, Japan. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Ishimaru, M (reprint author), Osaka Univ, Inst Sci & Ind Res, Osaka 5670047, Japan. NR 15 TC 5 Z9 5 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 18 PY 2000 VL 77 IS 25 BP 4151 EP 4153 AR PII [S0003-6951(01)01401-2] DI 10.1063/1.1335844 PG 3 WC Physics, Applied SC Physics GA 382LR UT WOS:000165824200024 ER PT J AU Gilbert, DR Novikov, A Patrin, N Budai, JD Kelly, F Chodelka, R Abbaschian, R Pearton, SJ Singh, R AF Gilbert, DR Novikov, A Patrin, N Budai, JD Kelly, F Chodelka, R Abbaschian, R Pearton, SJ Singh, R TI High-pressure process to produce GaN crystals SO APPLIED PHYSICS LETTERS LA English DT Article ID GROWTH AB High melt temperature and thermal decomposition prevent the use of standard bulk semiconductor crystal growth processes for the production of GaN. We have employed a hydrostatic pressure system to grow GaN crystals. An ultrahigh pressure, high temperature process was developed using a solid-phase nitrogen source to form GaN crystals in a Ga metal melt. Using a thermal gradient diffusion process, in which nitrogen dissolves in the high temperature region of the metal melt and diffuses to the lower temperature, lower solubility region, high quality crystals up to similar to1 mm in size were formed, as determined by scanning electron microscopy, x-ray diffraction, and micro-Raman analysis. (C) 2000 American Institute of Physics. [S0003- 6951(00)00650-1]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Gemesis Corp, Gainesville, FL 34228 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Singh, R (reprint author), Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. EM fkell@mse.ufl.edu; rsing@mse.ufl.edu RI Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 12 TC 6 Z9 6 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 18 PY 2000 VL 77 IS 25 BP 4172 EP 4174 AR PII [S0003-6951(00)00650-1] DI 10.1063/1.1330754 PG 3 WC Physics, Applied SC Physics GA 382LR UT WOS:000165824200031 ER PT J AU Zi, J Min, BJ Lu, Y Wang, CZ Ho, KM AF Zi, J Min, BJ Lu, Y Wang, CZ Ho, KM TI Dimer-flipping-assisted diffusion on a Si(001) surface SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SI(100) SURFACE; SI ADATOM; AB-INITIO; DYNAMICS; BINDING; SILICON; PSEUDOPOTENTIALS; MODEL; ATOM AB The binding sites and diffusion pathways of Si adatoms on a c(4x2) reconstructed Si(001) surface are investigated by a tight-binding method with an environment-dependent silicon potential in conjunction with ab initio calculations using the Car-Parrinello method. A new diffusion pathway along the trough edge driven by dimer flipping is found with a barrier of 0.74 eV, comparable to that of 0.68 eV along the top of the dimer rows. (C) 2000 American Institute of Physics. [S0003-6951(01)03401-5]. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Fudan Univ, Natl Key Lab, Surface Phys Lab, Shanghai 200433, Peoples R China. RP Zi, J (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI Zi, Jian/B-5102-2009; 上官, 敏慧/E-8964-2012 NR 22 TC 3 Z9 3 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 18 PY 2000 VL 77 IS 25 BP 4184 EP 4186 DI 10.1063/1.1336167 PG 3 WC Physics, Applied SC Physics GA 382LR UT WOS:000165824200035 ER PT J AU Xie, YY Aytug, T Wu, JZ Verebelyi, DT Paranthaman, M Goyal, A Christen, DK AF Xie, YY Aytug, T Wu, JZ Verebelyi, DT Paranthaman, M Goyal, A Christen, DK TI Epitaxy of HgBa2CaCu2O6 superconducting films on biaxially textured Ni substrates SO APPLIED PHYSICS LETTERS LA English DT Article ID CRITICAL-CURRENT DENSITY; THIN-FILMS; CATION-EXCHANGE; TEMPERATURE; GROWTH AB Superconducting HgBa2CaCu2O6 (Hg-1212) films have been coated on biaxially textured Ni substrates buffered with CeO2/YSZ/CeO2 trilayers. A two-step cation-exchange process was employed for Hg-1212 coatings, whereby epitaxial Tl2Ba2CaCu2O8 precursor films grown in a fast temperature ramping annealing process were converted to Hg-1212 via diffusive Hg-Tl cation exchange. This minimizes chemical diffusion/reaction of Hg with the substrates and allows Hg-1212 films to inherit the epitaxy and smooth surface morphology of the Tl2Ba2CaCu2O8 precursor films. The superconducting transition temperature (T-c) of these Hg-1212 coated conductors is up to 124 K. Self-field critical current densities (J(c)) of 2.2x10(6) A/cm(2) at 77 K have been obtained, with J(c) values of 0.7x10(6) A/cm(2) achieved at 100 K. These results show Hg-1212 coated conductors may hold promise for electrical power applications above 77 K. (C) 2000 American Institute of Physics. [S0003-6951(00)05151-2]. C1 Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Xie, YY (reprint author), Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. RI Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 17 TC 15 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 18 PY 2000 VL 77 IS 25 BP 4193 EP 4195 DI 10.1063/1.1333400 PG 3 WC Physics, Applied SC Physics GA 382LR UT WOS:000165824200038 ER PT J AU Prozorov, R Giannetta, RW Carrington, A Fournier, P Greene, RL Guptasarma, P Hinks, DG Banks, AR AF Prozorov, R Giannetta, RW Carrington, A Fournier, P Greene, RL Guptasarma, P Hinks, DG Banks, AR TI Measurements of the absolute value of the penetration depth in high-T-c superconductors using a low-T-c superconductive coating SO APPLIED PHYSICS LETTERS LA English DT Article ID MICROWAVE SURFACE IMPEDANCE; SINGLE-CRYSTALS; FIELD PENETRATION; YBA2CU3O6.95; INPLANE; YBA2CU3O7-DELTA; ANISOTROPY; GROWTH; STATE AB A method is presented to measure the absolute value of the London penetration depth, lambda (T=0), from the frequency shift of a resonator. The technique involves coating a high-T-c superconductor with film of low-T-c material of known thickness and penetration depth. The method is applied to obtain lambda (YBa2Cu3O7-delta)approximate to 1460 +/- 150 Angstrom, lambda (Bi2Sr2CaCu2O8+delta)approximate to 2690 +/- 150 Angstrom and lambda (Pr1.85Ce0.15CuO4- (delta))approximate to 2790 +/- 150 Angstrom. lambda (YBa2Cu3O7-delta) from this method is very close to that obtained by several other techniques. For both Bi2Sr2CaCu2O8+delta and Pr1.85Ce0.15CuO4-delta the values exceed those obtained by other methods. (C) 2000 American Institute of Physics. [S0003-6951(00)00148-0]. C1 Univ Illinois, Loomis Lab Phys, Urbana, IL 61801 USA. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Maryland, Ctr Superconduct Res, Dept Phys, College Pk, MD 20742 USA. Argonne Natl Lab, Div Mat & Chem Sci, Argonne, IL 60439 USA. Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. RP Prozorov, R (reprint author), Univ Illinois, Loomis Lab Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Prozorov, Ruslan/A-2487-2008 OI Prozorov, Ruslan/0000-0002-8088-6096 NR 25 TC 47 Z9 47 U1 1 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 18 PY 2000 VL 77 IS 25 BP 4202 EP 4204 DI 10.1063/1.1328362 PG 3 WC Physics, Applied SC Physics GA 382LR UT WOS:000165824200041 ER PT J AU Jenkins, AC Temmerman, WM Ahuja, R Eriksson, O Johansson, B Wills, J AF Jenkins, AC Temmerman, WM Ahuja, R Eriksson, O Johansson, B Wills, J TI The relationship between interlayer spacing and magnetic ordering in gadolinium SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID SPIN-DENSITY-APPROXIMATION; GENERALIZED GRADIENT APPROXIMATION; GROUND-STATE PROPERTIES; ELECTRONIC-STRUCTURE; GD(0001) SURFACE; BRILLOUIN-ZONE; SPECIAL POINTS; GD; EXCHANGE; METAL AB We report on the application of the local spin-density approximation (LSDA) and the generalized gradient approximation of Perdew, Burke and Ernzerhof(PBE) within the linear muffin-tin orbital method in both the atomic sphere approximation (LMTO-ASA) and in the full-potential (FP-LMTO) method to the description of the magnetic coupling within built Gd. Using the LMTO-ASA approach to the band-structure problem it is found that, at the experimental lattice parameters, the PBE approximation predicts the experimentally observed ferromagnetic (FM) ground state whereas the LSDA does not. Moreover the nature of the magnetic coupling between successive layers is found to be dependent on the interlayer separation-in particular a reduction of the interlayer spacing will lead to an increased tendency towards FM coupling between successive layers and, conversely, increase of the interlayer spacing will lead to antiferromagnetic (AFM) coupling between layers being energetically favourable. A similar interdependence between the interlayer spacing and the magnetic coupling is also observed from calculations using the FP-LMTO method. These observations are used to analyse the nature of the magnetic coupling of the Gd(0001) surface to the underlying FM bulk. C1 SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. Univ Uppsala, Dept Phys, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Jenkins, AC (reprint author), SERC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 40 TC 4 Z9 4 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD DEC 18 PY 2000 VL 12 IS 50 BP 10441 EP 10456 DI 10.1088/0953-8984/12/50/307 PG 16 WC Physics, Condensed Matter SC Physics GA 387LM UT WOS:000166124100010 ER PT J AU Chalmers, G Lechtenfeld, O Niemeyer, B AF Chalmers, G Lechtenfeld, O Niemeyer, B TI N=2 quantum string scattering SO NUCLEAR PHYSICS B LA English DT Article DE quantum string scattering; N=2 string; string loop amplitudes; spin structures; self-dual gravity ID MULTI-GLUON SCATTERING; SELF-DUAL GRAVITY; = 2 STRINGS; GAUGE-THEORIES; HELICITY AMPLITUDES; YANG-MILLS; SIMPLIFYING ALGEBRA; LOOP AMPLITUDES; FEYNMAN GRAPHS; FIELD-THEORY AB We calculate the genus-one three- and four-point amplitudes in thr (2 + 2)-dimensional closed N = (2.2) worldsheet supersymmetric string within the RNS formulation. Vertex operators are redefined with the incorporation of spinor helicity techniques, and the quantum scattering is shown to be manifestly gauge and Lorentz invariant after normalizing the string states. The continuous spin structure summation over the monodromies of the worldsheet fermions is carried out explicitly, and the field-theory limit is extracted. The amplitude in this limit is shown to be the maximally helicity violating amplitude in pure gravity evaluated in a two-dimensional setting, which vanishes, unlike the four-dimensional result. The vanishing of the genus-one N = 2 closed string amplitude is related to the absence of one-loop divergences in dimensionally regulated IIB supergravity. Comparisons and contrasts between self-dual field theory and the N = 2 string theory are made at the quantum level; they have different S-matrices. Finally, we point to further relations with self-dual field theory and two-dimensional models. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Hannover, Inst Theoret Phys, D-30167 Hannover, Germany. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. RP Lechtenfeld, O (reprint author), Univ Hannover, Inst Theoret Phys, Appelstr, D-30167 Hannover, Germany. NR 63 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 DEC 18 PY 2000 VL 591 IS 1-2 BP 39 EP 76 DI 10.1016/S0550-3213(00)00560-5 PG 38 WC Physics, Particles & Fields SC Physics GA 376UN UT WOS:000165475300003 ER PT J AU Gutierrez, TD Vogt, R Gunion, JF AF Gutierrez, TD Vogt, R Gunion, JF TI Higher twist contributions to R-hadron phenomenology in the light gluino scenario SO NUCLEAR PHYSICS B LA English DT Article DE charm meson and baryon hadroproduction ID PSI-PSI-PRODUCTION; YAN CROSS-SECTION; PI-P-INTERACTIONS; INTRINSIC CHARM; QUANTUM CHROMODYNAMICS; NUCLEUS INTERACTIONS; 800 GEV/C; LARGE-X; SEARCH; COLLISIONS AB The open light gluino window allows non-trivial higher-twist gluino contributions to the proton wave function. Using a two-component model originally developed for charm hadroproduction, higher-twist intrinsic gluino contributions to final-state R-hadron formation are shown to enhance leading-twist production in the forward x(F) region. We calculate R-hadron production at P-lab = 800 GeV in pp, pBe, and pCu interactions with light gluino masses of 1.2, 1.5, 3.5, and 5.0 GeV. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Berkeley, Div Nucl Sci, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. EM vogt@lbl.gov OI Gutierrez, Thomas/0000-0002-0330-6414 NR 53 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD DEC 18 PY 2000 VL 591 IS 1-2 BP 277 EP 295 DI 10.1016/S0550-3213(00)00556-3 PG 19 WC Physics, Particles & Fields SC Physics GA 376UN UT WOS:000165475300011 ER PT J AU Melnikov, K van Ritbergen, T AF Melnikov, K van Ritbergen, T TI The three-loop on-shell renormalization of QCD and QED SO NUCLEAR PHYSICS B LA English DT Article DE perturbative calculations; renormalization factors ID MASSIVE FEYNMAN-INTEGRALS; EFFECTIVE FIELD-THEORY; STATIC QUARK; DIAGRAMS; EXPONENTIATION; SUMS AB We describe a calculation of the on-shell renormalization factors in QCD and QED at the three loop level. Explicit results for the fermion mass renormalization factor Z(m) and the on-shell fermion wave function renormalization constant Z(2) are given. We find that at O(alpha (3)(s)) the wave function renormalization constant Z(2) in QCD becomes gauge dependent also in the on-shell scheme, thereby disproving the "gauge-independence" conjecture based on an earlier two-loop result. As a byproduct, we derive an O(alpha (3)(s)) contribution to the anomalous dimension of the heavy quark field in HQET. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Karlsruhe, Inst Theoret Teilchenphys, D-76128 Karlsruhe, Germany. RP Melnikov, K (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 45 TC 72 Z9 72 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 DEC 18 PY 2000 VL 591 IS 1-2 BP 515 EP 546 DI 10.1016/S0550-3213(00)00526-5 PG 32 WC Physics, Particles & Fields SC Physics GA 376UN UT WOS:000165475300019 ER PT J AU Hoffman, DK Kouri, DJ AF Hoffman, DK Kouri, DJ TI Hierarchy of local minimum solutions of Heisenberg's uncertainty principle SO PHYSICAL REVIEW LETTERS LA English DT Article ID PATH-INTEGRALS; PROPAGATOR; EXTENSIONS AB We derive a new hierarchy of local minimum Heisenberg-uncertainty states by introducing a superposition of "small waves" onto some initial state. Our objective is to increase the resolution in one observable, with the least decrease in the resolution in the conjugate observable. This leads to a constrained minimization which in a well-defined sense yields the best possible way of achieving this goal. The results are relevant to many topics (e.g., quantum optics and control, Bose-Einstein condensation, path integration, etc.). C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Univ Houston, Dept Chem, Houston, TX 77204 USA. RP Hoffman, DK (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. NR 34 TC 10 Z9 10 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 18 PY 2000 VL 85 IS 25 BP 5263 EP 5267 DI 10.1103/PhysRevLett.85.5263 PG 5 WC Physics, Multidisciplinary SC Physics GA 383LN UT WOS:000165884200001 PM 11135972 ER PT J AU Dodelson, S Kaplinghat, M Stewart, E AF Dodelson, S Kaplinghat, M Stewart, E TI Solving the coincidence problem: Tracking oscillating energy SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLD DARK-MATTER; MICROWAVE BACKGROUND ANISOTROPY; COSMOLOGICAL CONSTANT; UNIVERSE; LAMBDA; MODELS; CONSTRAINTS; STATE; CONSEQUENCES; PARAMETERS AB Recent cosmological observations strongly suggest that the Universe is dominated by an unknown form of energy with negative pressure. Why is this dark energy density of order the critical density today? We propose that the dark energy has periodically dominated in the past so that its preponderance toda; is natural. We illustrate this paradigm with a model potential and show that its predictions are consistent with all observations. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Korea Adv Inst Sci & Technol, Dept Phys, Taejon 305701, South Korea. RP Dodelson, S (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. RI Stewart, Ewan/C-1565-2011 NR 50 TC 128 Z9 129 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 DEC 18 PY 2000 VL 85 IS 25 BP 5276 EP 5279 DI 10.1103/PhysRevLett.85.5276 PG 4 WC Physics, Multidisciplinary SC Physics GA 383LN UT WOS:000165884200004 PM 11135975 ER PT J AU Quinn, HR Schietinger, T Silva, JP Snyder, AE AF Quinn, HR Schietinger, T Silva, JP Snyder, AE TI Using kaon regeneration to probe the quark mixing parameter cos2 beta in B ->psi K decays SO PHYSICAL REVIEW LETTERS LA English DT Article ID AMPLITUDE; VIOLATION AB We suggest a novel method to determine the sign of cos2 beta in the decays B --> psiK, by creating interference between K-L and K-S final states via "regeneration," that is propagation through a matter target region to convert some K-L to K-S. The determination of this quantity resolves an ambiguity between beta and 90 degrees - beta that remains after the standard measurements of sin2 beta and may turn out to be important in resolving whether the result is in agreement with standard model predictions or indicates the presence of new physics. We fmd the measurement is feasible at a B factory, but requires several years of high-luminosity running with a regeneration target affecting a significant fraction of the detector. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Inst Super Engn Lisboa, P-1900 Lisbon, Portugal. RP Quinn, HR (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Silva, Joao/A-2896-2009; Physics Department, ISEL/F-6664-2010 OI Silva, Joao/0000-0002-6455-9618; NR 27 TC 18 Z9 18 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 DEC 18 PY 2000 VL 85 IS 25 BP 5284 EP 5287 DI 10.1103/PhysRevLett.85.5284 PG 4 WC Physics, Multidisciplinary SC Physics GA 383LN UT WOS:000165884200006 PM 11135977 ER PT J AU Pumir, A Shraiman, BI Chertkov, M AF Pumir, A Shraiman, BI Chertkov, M TI Geometry of Lagrangian dispersion in turbulence SO PHYSICAL REVIEW LETTERS LA English DT Article ID PASSIVE SCALAR ADVECTION; NUMERICAL SIMULATIONS; ISOTROPIC TURBULENCE; PAIR DISPERSION; LOCAL ISOTROPY; FLOWS AB Turbulent flows disperse Lagrangian particles resulting in the growth of pairwise separations and, for sets of three or more particles, in a nontrivial dynamics of their configuration. The shape of such clusters is controlled by the competition between coherent straining of the cluster and the independent random motion of the particles due to small scale velocity fluctuations. We introduce a statistical description of the geometry of the Lagrangian clusters and predict a self-similar distribution of shapes, which should be observable in the inertial range of scales in high Reynolds numbers flows. C1 INLN, F-06560 Valbonne, France. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. LANL, CNLS, Los Alamos, NM 87545 USA. LANL, Theoret Div T 13, Los Alamos, NM 87545 USA. RP Pumir, A (reprint author), INLN, 1361 Route Lucioles, F-06560 Valbonne, France. RI Chertkov, Michael/O-8828-2015 NR 27 TC 66 Z9 66 U1 2 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 18 PY 2000 VL 85 IS 25 BP 5324 EP 5327 DI 10.1103/PhysRevLett.85.5324 PG 4 WC Physics, Multidisciplinary SC Physics GA 383LN UT WOS:000165884200016 PM 11135987 ER PT J AU Patterson, JR Catledge, SA Vohra, YK Akella, J Weir, ST AF Patterson, JR Catledge, SA Vohra, YK Akella, J Weir, ST TI Electrical and mechanical properties of C-70 fullerene and graphite under high pressures studied using designer diamond anvils SO PHYSICAL REVIEW LETTERS LA English DT Article AB We compare electrical and mechanical properties of C-70 fullerene with high purity graphite to 48 GPa at room temperature using designer diamond anvils with embedded electrical microprobes. The electrical resistance of C-70 shows a minimum at 20 GPa with transformation to an amorphous insulating phase complete above 35 GPa, while graphite remains conducting. Nanoindentation shows hardness values 220 times larger for the pressure quenched amorphous phase than for similarly treated graphite. Our studies establish that the amorphous carbon phase produced from C-70 has unique properties not attainable from graphite. C1 Univ Alabama, Dept Phys, Birmingham, AL 35294 USA. LLNL, Livermore, CA 94550 USA. RP Patterson, JR (reprint author), Univ Alabama, Dept Phys, Birmingham, AL 35294 USA. RI Weir, Samuel/H-5046-2012 NR 11 TC 63 Z9 67 U1 0 U2 17 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 DEC 18 PY 2000 VL 85 IS 25 BP 5364 EP 5367 DI 10.1103/PhysRevLett.85.5364 PG 4 WC Physics, Multidisciplinary SC Physics GA 383LN UT WOS:000165884200026 PM 11135997 ER PT J AU Olson, CJ Zimanyi, GT Kolton, AB Gronbech-Jensen, N AF Olson, CJ Zimanyi, GT Kolton, AB Gronbech-Jensen, N TI Static and dynamic coupling transitions of vortex lattices in disordered anisotropic superconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLUX-LINE-LATTICE; HIGH-TEMPERATURE SUPERCONDUCTORS; PHASE-DIAGRAM; LAYERED SUPERCONDUCTORS; SINGLE-CRYSTALS; PERIODIC MEDIA; VORTICES; BI2SR2CACU2O8; CROSSOVER; SYSTEMS AB We use three-dimensional molecular dynamics simulations of magnetically interacting pancake vortices to study vortex matter in disordered, highly anisotropic materials such as BSCCO. We observe a sharp 3D-2D transition from vortex lines to decoupled pancakes as a function of relative interlayer coupling strength, with an accompanying large increase in the critical current reminiscent of a second peak effect. We find that decoupled pancakes, hen driven, simultaneously recouple and order into a crystallinelike state at high drives. We construct a dynamic phase diagram and show that the dynamic recoupling transition is associated with a double peak in dV/dl. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Olson, CJ (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. OI Reichhardt, Cynthia/0000-0002-3487-5089; Kolton, Alejandro B./0000-0002-9050-5859 NR 40 TC 50 Z9 51 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 DEC 18 PY 2000 VL 85 IS 25 BP 5416 EP 5419 DI 10.1103/PhysRevLett.85.5416 PG 4 WC Physics, Multidisciplinary SC Physics GA 383LN UT WOS:000165884200039 PM 11136010 ER PT J AU Moler, EJ Chow, ML Mian, IS AF Moler, EJ Chow, ML Mian, IS TI Analysis of molecular profile data using generative and discriminative methods SO PHYSIOLOGICAL GENOMICS LA English DT Article DE microarrays; biological networks; graphical models; support vector machines; decision support systems; comparative molecular; profile data analysis ID SELF-ORGANIZING MAPS; GENE-EXPRESSION DATA; CANCER CELL-LINES; SACCHAROMYCES-CEREVISIAE; PROTEIN EXPRESSION; TUMOR; PATTERNS; BIOLOGY; ADENOCARCINOMA; KNOWLEDGE AB A modular framework is proposed for modeling and understanding the relationships between molecular profile data and other domain knowledge using a combination of generative (here, graphical models) and discriminative [Support Vector Machines (SVMs)] methods. As illustration, naive Bayes models, simple graphical models, and SVMs were applied to published transcription profile data for 1,988 genes in 62 colon adenocarcinoma tissue specimens labeled as tumor or nontumor. These unsupervised and supervised learning methods identified three classes or subtypes of specimens, assigned tumor or nontumor labels to new specimens and detected six potentially mislabeled specimens. The probability parameters of the three classes were utilized to develop a novel gene relevance, ranking, and selection method. SVMs trained to discriminate nontumor from tumor specimens using only the 50-200 top-ranked genes had the same or better generalization performance than the full repertoire of 1,988 genes. Approximately 90 marker genes were pinpointed for use in understanding the basic biology of colon adenocarcinoma, defining targets for therapeutic intervention and developing diagnostic tools. These potential markers highlight the importance of tissue biology in the etiology of cancer. Comparative analysis of molecular profile data is proposed as a mechanism for predicting the physiological function of genes in instances when comparative sequence analysis proves uninformative, such as with human and yeast translationally controlled tumour protein. Graphical models and SVMs hold promise as the foundations for developing decision support systems for diagnosis, prognosis, and monitoring as well as inferring biological networks. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Life Sci Div,Radiat Biol & Environm Toxicol Grp, Berkeley, CA 94720 USA. RP Mian, IS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Life Sci Div,Radiat Biol & Environm Toxicol Grp, MS 74-197,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM SMian@lbl.gov NR 52 TC 52 Z9 52 U1 0 U2 3 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 1094-8341 EI 1531-2267 J9 PHYSIOL GENOMICS JI Physiol. Genomics PD DEC 18 PY 2000 VL 4 IS 2 BP 109 EP 126 PG 18 WC Cell Biology; Genetics & Heredity; Physiology SC Cell Biology; Genetics & Heredity; Physiology GA 383WR UT WOS:000165908100002 PM 11120872 ER PT J AU Moler, EJ Radisky, DC Mian, IS AF Moler, EJ Radisky, DC Mian, IS TI Integrating naive Bayes models and external knowledge to examine copper and iron homeostasis in S-cerevisiae SO PHYSIOLOGICAL GENOMICS LA English DT Article DE molecular profile matrix; gene profile vectors; naive Bayes model; copper and iron metabolism; Bayesian networks ID SELF-ORGANIZING MAPS; GENE-EXPRESSION; PATTERNS; PROTEIN; DATABASE; TUMOR AB A novel suite of analytical techniques and visualization tools are applied to 78 published transcription profiling experiments monitoring 5,687 Saccharomyces cerevisiae genes in studies examining cell cycle, responses to stress, and diauxic shift. A naive Bayes model discovered and characterized 45 classes of gene profile vectors. An enrichment measure quantified the association between these classes and specific external knowledge defined by four sets of categories to which genes can be assigned: 106 protein functions, 5 stages of the cell cycle, 265 transcription factors, and 16 chromosomal locations. Many of the 38 genes in class 42 are known to play roles in copper and iron homeostasis. The 17 uncharacterized open reading frames in this class may be involved in similar homeostatic processes; human homologs of two of them could be associated with as yet undefined disease states arising from aberrant metal ion regulation. The Met4, Met31, and Met32 transcription factors may play a role in coregulating genes involved in copper and iron metabolism. Extensions of the simple graphical model used for clustering to learning more complex models of genetic networks are discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Radiat Biol & Environm Toxicol Grp,Life Sci Div, Berkeley, CA 94720 USA. RP Mian, IS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Radiat Biol & Environm Toxicol Grp,Life Sci Div, MS 74-197,1 Cyclotron Rd, Berkeley, CA 94720 USA. EM SMian@lbl.gov NR 31 TC 33 Z9 33 U1 0 U2 1 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 1094-8341 EI 1531-2267 J9 PHYSIOL GENOMICS JI Physiol. Genomics PD DEC 18 PY 2000 VL 4 IS 2 BP 127 EP 135 PG 9 WC Cell Biology; Genetics & Heredity; Physiology SC Cell Biology; Genetics & Heredity; Physiology GA 383WR UT WOS:000165908100003 PM 11120873 ER PT J AU Peles, JD Bryan, AL Garten, CT Ribble, DO Smith, MH AF Peles, JD Bryan, AL Garten, CT Ribble, DO Smith, MH TI Ecological half-life of Cs-137 in fish from a stream contaminated by nuclear reactor effluents SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE radiocesium; ecological half-life; long-term decline; fish; risk assessment ID COOLING RESERVOIR; RADIOCESIUM; LAKES; SEDIMENTS; CHERNOBYL; TRENDS AB Radiocesium (Cs-137) concentrations were determined during 1974, 1981 and 1998 for seven species of fish inhabiting a stream (Steel Creek) contaminated by effluents from a nuclear reactor to examine the decline of this radionuclide in a natural ecosystem. Median Cs-137 concentrations were highest in Micropterus salmoides (largemouth bass) during each year of the investigation (1974 = 6.67 Bq g(-1) dry wt. of whole body; 1981 = 3.72 Bq g(-1) 1998 = 0.35 Bq g(-1)), but no patterns of differences were observed among Aphredoderus sayanus (pirate perch), Esox americanus (redfin pickerel), Lepomis auritus (redbreast sunfish), L. gulosus (warmouth), L. punctatus (spotted sunfish), and Notropis cummingsae (dusky shiner). Results demonstrated a rapid decline in Cs-137 within fish from Steel Creek during the 24-year period. For example, Cs-137 concentrations in all fish species declined significantly among years, even after accounting for radioactive decay. The observed percent declines in Cs-137 concentrations of individual species were 3-4 times greater between 1974 and 1981 compared to that expected by physical decay alone, and 2-3 times greater during 1981-1998. Ecological half-lives (EHLs) of Cs-137 in fish ranged from 4.43 years in A. sayanus to 6.53 years in L. gulosus. The EHL for Cs-137 in all fish species combined was 5.54 years. Current levels of Cs-137 in fish from Steel Creek (1.16 Bq g(-1) dry wt, of whole body to below detection limits) indicate that the consumption of fish from this ecosystem poses little risk to humans and sensitive wildlife species. These results demonstrate the importance of incorporating the concept of ecological half-life into determinations concerning the length and severity of potential risks associated with radiocontaminants. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Penn State Univ, Ostermayer Lab 207, McKeesport, PA 15132 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37830 USA. Trinity Univ, Dept Biol, San Antonio, TX 78212 USA. Univ Georgia, Sch Forest Resources, Athens, GA 30602 USA. Univ Georgia, Inst Ecol, Dept Genet, Athens, GA 30602 USA. RP Peles, JD (reprint author), Penn State Univ, Ostermayer Lab 207, 4000 Univ Dr, McKeesport, PA 15132 USA. NR 20 TC 7 Z9 7 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD DEC 18 PY 2000 VL 263 IS 1-3 BP 255 EP 262 DI 10.1016/S0048-9697(00)00713-0 PG 8 WC Environmental Sciences SC Environmental Sciences & Ecology GA 389NC UT WOS:000166243600023 PM 11194159 ER PT J AU Manney, GL Michelsen, HA Irion, FW Toon, GC Gunson, MR Roche, AE AF Manney, GL Michelsen, HA Irion, FW Toon, GC Gunson, MR Roche, AE TI Lamination and polar vortex development in fall from ATMOS long-lived trace gases observed during November 1994 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE LAMINAE; WATER-VAPOR; ATMOS/ATLAS-3 MEASUREMENTS; STRATOSPHERIC ABUNDANCES; TRAJECTORY CALCULATIONS; NORTHERN STRATOSPHERE; POTENTIAL VORTICITY; WAVE BREAKING; EARLY WINTER; CLIMATOLOGY AB Long-lived trace-gas profiles observed by the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument around the developing polar vortex (the "protovortex") during early November 1994 show distinctive inversions (laminae). High-resolution profiles calculated using a reverse trajectory (RT) model reproduce the majority of these laminae, demonstrating that most of these features arise from advection by the large-scale winds. The relationship between CH(4) and N(2)O sampled in filaments of low-latitude air changes from the canonical midlatitude correlation to one typical of tropical air, confirming the identification of tropical laminae, N(2)O/CH(4) correlations for laminae in vortex filaments indicate that enough confined descent and mixing has already occurred in the middle and upper stratosphere by early November to alter the tracer relationship in the protovortex from that in midlatitudes. Distributions of laminae in ATMOS observations agree with regions of greater or less filamentation seen in high-resolution RT maps. There is a deep minimum in laminae occurrence between 30 degrees and 90 degreesE at all levels, extending to about 150 degreesE above similar to 35 km. Maxima in lamination in the lower stratosphere near 90 degrees -150 degreesE and 210 degrees -270 degreesE are associated with the main regions where tropical air is drawn up around the developing vortex. Continuous filamentation associated with the developing vortex and anticyclone in early November 1994 shows that transport and mixing processes previously reported during winter are already important during fall. C1 New Mexico Highlands Univ, Dept Phys, Las Vegas, NM 87701 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Sandia Natl Labs, Livermore, CA 94551 USA. Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. RP Manney, GL (reprint author), New Mexico Highlands Univ, Dept Phys, Las Vegas, NM 87701 USA. EM manney@mls.jpl.nasa.gov NR 38 TC 30 Z9 30 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD DEC 16 PY 2000 VL 105 IS D23 BP 29023 EP 29038 DI 10.1029/2000JD900428 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 389UQ UT WOS:000166257400010 ER PT J AU Xu, GP Sygula, A Marcinow, Z Rabideau, PW AF Xu, GP Sygula, A Marcinow, Z Rabideau, PW TI Chemistry on the rim of buckybowls: derivatization of 1,2,5,6-tetrabromocorannulene SO TETRAHEDRON LETTERS LA English DT Article ID CORANNULENE; SEMIBUCKMINSTERFULLERENE AB Synthesis of a number of substituted corannulenes and dibenzo[a,g]corannulenes starting from 1,2,5,6-tetrabromocorannulene 3 is described. Since 3 is conveniently obtained by a large scale, non-pyrolytic route, it may serve as a synthon for the further elaboration of this bowl-shaped system. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RP Rabideau, PW (reprint author), Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. NR 19 TC 28 Z9 28 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD DEC 16 PY 2000 VL 41 IS 51 BP 9931 EP 9934 DI 10.1016/S0040-4039(00)01785-8 PG 4 WC Chemistry, Organic SC Chemistry GA 384TC UT WOS:000165960100001 ER PT J AU Saiz, E Cannon, RM Tomsia, AP AF Saiz, E Cannon, RM Tomsia, AP TI Enhanced atomic transport at liquid metal/Al2O3 interfaces SO ADVANCED MATERIALS LA English DT Article ID SURFACE THERMAL GROOVES; DIHEDRAL ANGLES; ALUMINA; DIFFUSION; METALS; OXIDES AB The mechanisms involved in mass transport at the metal/oxide interface are important for understanding the atomic structure at such boundaries. These authors have used AFM and SEM to study the evolution of grain boundary grooves at the interface between liquid metals (Ni, Al (see Figure), Cu, Au) and pure polycrystalline alumina, and present data that should be fundamental to modeling interactions between liquid metals and oxides. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. EM aptomsia@lbl.gov NR 21 TC 5 Z9 5 U1 3 U2 20 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA POSTFACH 101161, 69451 WEINHEIM, GERMANY SN 0935-9648 EI 1521-4095 J9 ADV MATER JI Adv. Mater. PD DEC 15 PY 2000 VL 12 IS 24 BP 1952 EP + DI 10.1002/1521-4095(200012)12:24<1952::AID-ADMA1952>3.0.CO;2-# PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 393XM UT WOS:000166495000016 ER PT J AU Shinar, R Liu, GJ Porter, MD AF Shinar, R Liu, GJ Porter, MD TI Graphite microparticles as coatings for quartz crystal microbalance-based gas sensors SO ANALYTICAL CHEMISTRY LA English DT Article ID VISCOELASTIC FILM PROPERTIES; ORGANIC VAPOR; CARBON; RESPONSES; ARRAYS; RESONATORS; DYNAMICS; MODULUS AB The use of graphite particles (1-2 pm) as coatings on quartz crystal microbalances (QCMs) for detection and monitoring of toluene and other volatile organic compounds (VOCs) is described. Unlike the more commonly used polymeric coatings with low glass transition temperatures (T-g) particulate graphitic coatings are not as susceptible to loss of acoustic energy when coating thickness or operational temperature increases. This situation enables the use of relatively thick coatings, which increases the absolute amount of vapor sorbed in the coating and, consequently, lowers the level of detection and enhances operation over a wide temperature range. The use of small size particles also results in a coating with a more porous structure, which facilitates uptake and release of VOCs incomparison to coatings made from high T-g polymers, which have a lower porosity, These attributes, coupled with the inherent stability of graphitic materials, make particulate graphite coatings especially suitable for applications at high temperatures. The advantages of using particulate graphite as a coating on QCMs are demonstrated by comparison to the performance of a few low-T-g polymers [i.e., poly(isobutylene) and poly(diphenoxyphosphazene)] and high-T-g polymers (i.e,, polystyrene). C1 Iowa State Univ, US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Shinar, R (reprint author), Iowa State Univ, US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. NR 35 TC 25 Z9 26 U1 2 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD DEC 15 PY 2000 VL 72 IS 24 BP 5981 EP 5987 DI 10.1021/ac0009584 PG 7 WC Chemistry, Analytical SC Chemistry GA 383JT UT WOS:000165879900017 PM 11140766 ER PT J AU Singh, AK Harrison, SH Schoeniger, JS AF Singh, AK Harrison, SH Schoeniger, JS TI Gangliosides as receptors for biological toxins: Development of sensitive fluoroimmunoassays using ganglioside-bearing liposomes SO ANALYTICAL CHEMISTRY LA English DT Article ID CHOLERA-TOXIN; COLORIMETRIC DETECTION; MOLECULAR RECOGNITION; MEMBRANE-RECEPTORS; FLUORESCENCE; DEACTIVATION; ADSORPTION; PROTEINS; BINDING AB Gangliosides, glycosphingolipids present in the membranes of neuronal and other cells, are natural receptors for a number of bacterial toxins and viruses whose sensitive detection is of interest in clinical medicine as well as in biological warfare or terrorism incidents. Liposomes containing gangliosides mimic cells that are invaded by bacterial toxins and can be used as sensitive probes for detecting these toxins. We discuss detection of three bacterial toxins-tetanus, botulinum, and cholera toxins using ganglioside-bearing liposomes, Tetanus and botulinum toxins selectively bind gangliosides of the Gib series, namely, GT1b, GD1b, and GQ1b; and cholera toxin binds GM1 very specifically. Unilamellar liposomes containing GT1b or GM1 as one of the constituent lipids were prepared by extrusion through polycarbonate membranes. To impart signal generation capability to these liposomes, fluorophore-labeled lipids were incorporated in the bilayer of liposomes. The fluorescent liposomes, containing both a marker (rhodamine) and a receptor (GT1b or GM1) in the bilayer, were used in sandwich fluoroimmunoassays for tetanus, botulinum, and cholera toxins and as low as 1 nM of each toxin could be detected, The apparent dissociation constants of liposome-toxin complexes were in 10(-8) M range, indicating strong binding, This is the first report on detection of tetanus and botulinum toxins based on specific recognition by gangliosides. The fluorescent liposomes are attractive as immunoreagents for another reason as well-they provide: enormous signal amplification for each binding event as each liposome contains up to 22 000 rhodamine molecules. The present approach using receptors incoporated in bilayers of liposomes offers a unique solution to employ water-insoluble receptors, such as glycolipids and membrane proteins, for sensitive detection of toxins and other clinically important biomolecules. C1 Sandia Natl Labs, Chem & Radiat Detect Lab, Livermore, CA 94550 USA. RP Singh, AK (reprint author), Sandia Natl Labs, Chem & Radiat Detect Lab, Livermore, CA 94550 USA. NR 37 TC 94 Z9 98 U1 2 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD DEC 15 PY 2000 VL 72 IS 24 BP 6019 EP 6024 DI 10.1021/ac0008461 PG 6 WC Chemistry, Analytical SC Chemistry GA 383JT UT WOS:000165879900022 PM 11140771 ER PT J AU Pedraza, AJ Fowlkes, JD Jesse, S Mao, C Lowndes, DH AF Pedraza, AJ Fowlkes, JD Jesse, S Mao, C Lowndes, DH TI Surface micro-structuring of silicon by excimer-laser irradiation in reactive atmospheres SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT Spring Meeting of the European-Materials-Research-Society CY MAY 30-JUN 02, 2000 CL STRASBOURG, FRANCE SP European Mat Res Soc DE laser-irradiation; laser-etching; silicon; micro-columns; micro-cones; nano-structures ID PULSES AB The formation mechanisms of cones and columns by pulsed-laser irradiation in reactive atmospheres were studied using scanning electron microscopy and profilometry. Deep etching takes place in SF6- and O-2- rich atmospheres and consequently, silicon-containing molecules and clusters are released. Transport of silicon from the etched/ablated regions to the tip of columns and cones and to the side of the cones is required because both structures, columns and cones, protrude above the initial surface. The laser-induced micro-structure is influenced not only by the nature but also by the partial pressure of the reactive gas in the atmosphere. Irradiation in Ar following cone formation in SF6 produced no additional growth but rather melting and resolidification. Subsequent irradiation using again a SF6 atmosphere lead to cone restructuring and growth resumption. Thus the effects of etching plus re-deposition that produce column/cone formation and growth are clearly separated from the effects of just melting. On the other hand, irradiation continued in air after first performed in SF6 resulted in: (a) an intense etching of the cones and a tendency to transform them into columns; (b) growth of new columns on top of the existing cones and (c) filamentary nano-structures coating the sides of the columns and cones. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Pedraza, AJ (reprint author), Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. RI Jesse, Stephen/D-3975-2016 OI Mao, Chuanbin/0000-0002-8142-3659; Jesse, Stephen/0000-0002-1168-8483 NR 15 TC 34 Z9 40 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD DEC 15 PY 2000 VL 168 IS 1-4 BP 251 EP 257 DI 10.1016/S0169-4332(00)00611-5 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 388MH UT WOS:000166184400058 ER PT J AU Teghil, R D'Alessio, L Simone, MA Zaccagnino, M Ferro, D Sordelet, DJ AF Teghil, R D'Alessio, L Simone, MA Zaccagnino, M Ferro, D Sordelet, DJ TI Pulsed laser ablation of Al-Cu-Fe quasicrystals SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT Spring Meeting of the European-Materials-Research-Society CY MAY 30-JUN 02, 2000 CL STRASBOURG, FRANCE SP European Mat Res Soc DE quasicrystals; laser ablation; film deposition AB Quasicrystalline Al-65-Cu-23-Fe-12 targets have been ablated by a doubled Nd:YAG laser and deposited on silicon substrates. The results show evidence of distinct ablation mechanisms, which lead to different gas phase composition, as a function of the laser fluence. Films containing the quasicrystalline phase can be deposited only at fluences higher than about 6.5 J/cm(2) while at lower fluences the aluminium content exceeds the stoichiometric value. The films obtained by laser ablation of quasicrystalline Al-65-Cu-23-Fe-12 were compared with those obtained from the metallic alloy Al-70-Cu-20-Fe-10. The differences between the two systems could be explained on the basis of the low thermal conductivity of the quasicrystalline phase. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Basilicata, Dipartimento Chim, I-85100 Potenza, Italy. Ctr Termodinam Chim Alte Temp, CNR, Rome, Italy. Iowa State Univ, Ames Lab, Dept Mat Sci & Engn, Ames, IA USA. RP Teghil, R (reprint author), Univ Basilicata, Dipartimento Chim, Via N Sauro 85, I-85100 Potenza, Italy. OI TEGHIL, ROBERTO/0000-0002-8528-8669 NR 7 TC 23 Z9 25 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD DEC 15 PY 2000 VL 168 IS 1-4 BP 267 EP 269 DI 10.1016/S0169-4332(00)00620-6 PG 3 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 388MH UT WOS:000166184400061 ER PT J AU Liu, Z Gomez, H Neumark, DM AF Liu, Z Gomez, H Neumark, DM TI Photoelectron spectroscopy of clustered transition state precursors IHI-center dot Ar and BrHI-center dot Ar SO CHEMICAL PHYSICS LETTERS LA English DT Article ID NEGATIVE-ION PHOTODETACHMENT; SPECTRA; DYNAMICS; REGION AB Photoelectron (PE) spectra of the IHI- Ar and BrHI- . Ar clusters were measured in order to probe the effect of clustering on the transition state spectroscopy of the X + HI --> XH + I (X=I, Br) reactions. Addition of one argon atom to XHI- leads to a shift of the IHI- and BrHI- spectra to lower electron kinetic energies by 18 and 36 meV, respectively. It also significantly reduces the contribution of vibrational hot bands to the photoelectron spectra. The IHI- Ar spectrum shows a new progression corresponding to hindered IHI rotor states near the I + HT (nu = 1) threshold. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Neumark, DM (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 25 TC 19 Z9 19 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 15 PY 2000 VL 332 IS 1-2 BP 65 EP 72 DI 10.1016/S0009-2614(00)01243-4 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 383KW UT WOS:000165882500010 ER PT J AU Fitts, JP Brown, GE Parks, GA AF Fitts, JP Brown, GE Parks, GA TI Structural evolution of Cr(III) polymeric species at the gamma-Al2O3/water interface SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID X-RAY-ABSORPTION; OXIDE WATER INTERFACE; AQUEOUS-SOLUTION; CHROMIUM(III); SORPTION; ADSORPTION; KINETICS; SPECTROSCOPY; HYDROLYSIS; XAFS AB We have characterized the structure of the predominant Cr(III) species present at the gamma -Al2O3/water interface as a function of equilibration time and Cr(III) surface loading using X-ray absorption fine structure (XAFS) spectroscopy. The spectroscopic measurements span two distinct time periods of Cr(III) uptake. During the initial period (<2 h), which is characterized by rapid uptake, Cr(III) monomers form inner-sphere complexes on the -Al2O3 surface by bonding to at least two surface functional groups. During the second period (ranging from 2 h to 1 week), significant quantities of Cr(III) continue to be removed from solution, but sorption proceeds at a greatly reduced rate. The XAFS spectra collected during the period of slow uptake show an increase in scattering contributions from neighboring Cr(III) atoms with increasing equilibration time. The inferred structural changes are consistent with a progression from hydroxo-bridged Cr(III) dimers to higher-order polymers. In combination with spectroscopic evidence, which shows that monomeric Cr(III) species are the only significant reactants in solution, the observed evolution of Cr(III) surface species suggests that chemical bonding between adsorbed Cr(III) ions and gamma -Al2O3 surface functional groups enhances Cr(III) polymerization. The proposed reaction sequence has important implications for surface complexation modeling used to predict Cr(III) partitioning by hydroxide sorbents in wastewater treatment and contaminant migration scenarios. C1 Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Brown, GE (reprint author), Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Bldg 320,Rm 118, Stanford, CA 94305 USA. RI Fitts, Jeffrey/J-3633-2012 NR 44 TC 21 Z9 22 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD DEC 15 PY 2000 VL 34 IS 24 BP 5122 EP 5128 DI 10.1021/es9914285 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 383NA UT WOS:000165887800009 ER PT J AU Chilakapati, A Williams, M Yabusaki, S Cole, C Szecsody, J AF Chilakapati, A Williams, M Yabusaki, S Cole, C Szecsody, J TI Optimal design of an in situ Fe(II) barrier: Transport limited reoxidation SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID REDUCTION; REMEDIATION; GROUNDWATER AB Harmful contaminants such as Cr(VI) and TCE can be removed from groundwater by reactions with chemically reduced subsurface sediments. This paper studies the optimal selection of the number of wells, the injection rate, and the number of regenerations of a large-scale Fe(II) barrier for Cr(VI) remediation at Hanford, WA. The process model consists of two parts: (a) the creation of the Fe(II) barrier by the injection of a dithionite reagent and (b) the reoxidation of the barrier by Cr(VI) and oxygen in the invading groundwater. The solution to the process model is used to develop the total cost as a function of the design variables. This cost model is applied to the Cr(VI) contamination at Hanford to obtain the optimal design configuration and its sensitivity to cost and process uncertainties. C1 Xerago LLC, San Diego, CA 92101 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Chilakapati, A (reprint author), Xerago LLC, 2535 Kettner Blvd,Suite 2A2, San Diego, CA 92101 USA. NR 18 TC 18 Z9 18 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD DEC 15 PY 2000 VL 34 IS 24 BP 5215 EP 5221 DI 10.1021/es000920h PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 383NA UT WOS:000165887800024 ER PT J AU Guilderson, TP Burckle, L Hemming, S Peltier, WR AF Guilderson, T. P. Burckle, L. Hemming, S. Peltier, W. R. TI Late Pleistocene sea level variations derived from the Argentine Shelf SO GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS LA English DT Article DE Sea level; Pleistocene; Argentina; eustacy; last glacial maximum AB Neritic-littoral marine sedimentary deposits from the Argentine Shelf provide a record of late Pleistocene sea level variation. Sediments interpreted to reflect the last glacial maximum low-stand are similar to 150 m below present. Using a simple Airy isostatic model for hydroisostatic compensation and correcting for a minor tectonic component yields a local eustatic sea level lowering of similar to 105 m at the last glacial maximum. The deglacial sea level curve records two rapid sea level rises consistent with MWP1-A and 1-B as documented by the Barbados coral-based sea level curve. Comparison with relative sea level variations predicted by the ICE4G VM2 viscoelastic model have highlighted a deficiency in the model's predicted sea level history for this region. Detailed data-model comparisons of late Pleistocene sea level variations are necessary in the face of climate change induced sea level perturbations to determine regional and or systematic biases in the treatment of lithosphere viscosity and accurate predictions of future sea level. C1 [Guilderson, T. P.] Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. [Guilderson, T. P.] Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. [Burckle, L.; Hemming, S.] Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. [Peltier, W. R.] Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. RP Guilderson, TP (reprint author), Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. EM guilderson@popeye.llnl.gov RI Peltier, William/A-1102-2008 FU Lamont-Doherty Earth Observatory Climate Center; Lawrence Livermore National Laboratory; NSF; U.S. Department of Energy [W-7405-Eng-48] FX This research was supported by a Lamont-Doherty Earth Observatory Climate Center grant and internal funds at Lawrence Livermore National Laboratory supporting postdoctoral research. The LDEO core repository is supported by the NSF. Radiocarbon analyses were performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory (contract W-7405-Eng-48). This manuscript benefited from comments and reviews by E. Bard and an anonymous reviewer and discussions with N. Slowey and U. Radtke. We thank R. Drummond for assistance and would especially like to acknowledge W. S. Broecker's support and the late M. Ewing. Digital data will be archived at World Data Center-A (http://www.ngdc.noaa.gov), Boulder, Colorado. This in LDEO contribution 6117 NR 34 TC 0 Z9 0 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 1525-2027 J9 GEOCHEM GEOPHY GEOSY JI Geochem. Geophys. Geosyst. PD DEC 15 PY 2000 VL 1 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA V22KK UT WOS:000208273900001 ER PT J AU Novakov, T Andreae, MO Gabriel, R Kirchstetter, TW Mayol-Bracero, OL Ramanathan, V AF Novakov, T Andreae, MO Gabriel, R Kirchstetter, TW Mayol-Bracero, OL Ramanathan, V TI Origin of carbonaceous aerosols over the tropical Indian Ocean: Biomass burning or fossil fuels? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PRE-INDOEX CRUISE; ATMOSPHERIC AEROSOL; URBAN; PARTICLES; HYDROCARBONS; EMISSIONS; SAPPORO; JAPAN; SIZE; ASIA AB We present an analysis of the carbon, potassium and sulfate content of the extensive aerosol haze layer observed over the tropical Indian Ocean during the Indian Ocean Experiment (INDOEX). The black carbon (BC) content of the haze is as high as 17% of the total fine particle mass (the sum of carbonaceous and soluble ionic aerosol components) which results in significant solar absorption. The ratio of black carbon to organic carbon (OC) lover the Arabian Sea and equatorial Indian Ocean) was a factor of 5 to 10 times larger than expected for biomass burning. This ratio was closer to values measured downwind of industrialized regions in Japan and Western Europe. These results indicate that fossil fuel combustion is the major source of carbonaceous aerosols, including black carbon during the events considered. If the data set analyzed here is representative of the entire INDOEX study then fossil fuel emissions from South Asia must have similarly contributed to aerosols over the whole study region. The INDOEX ratios are substantially different from those reported for some source regions of South Asia, thus raising the possibility that changes in composition of carbonaceous aerosol may occur during transport. C1 Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. Max Planck Inst Chem, Biogeochem Dept, D-55020 Mainz, Germany. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Novakov, T (reprint author), Lawrence Berkeley Lab, Environm Energy Technol Div, MS-73,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Andreae, Meinrat/B-1068-2008 OI Andreae, Meinrat/0000-0003-1968-7925 NR 26 TC 140 Z9 149 U1 3 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD DEC 15 PY 2000 VL 27 IS 24 BP 4061 EP 4064 DI 10.1029/2000GL011759 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 390TB UT WOS:000166311700025 ER PT J AU Taylor, JA Orr, JC AF Taylor, JA Orr, JC TI The natural latitudinal distribution of atmospheric CO2 SO GLOBAL AND PLANETARY CHANGE LA English DT Article DE natural latitudinal distribution; anthropogenic CO2; terrestrial biosphere ID CARBON-DIOXIDE; TRANSPORT; MODEL; CIRCULATION; EXCHANGE; OCEAN; SINKS; BIOSPHERE; BUDGET; CYCLE AB Although poorly understood, the north-south distribution of the natural component of atmospheric CO2 offers information essential to improving our understanding of the exchange of CO2 between the atmosphere, oceans, and biosphere. The natural or unperturbed component is equivalent to that part of the atmospheric CO2 distribution which is controlled by non-anthropogenic CO2, fluxes from the ocean and terrestrial biosphere. Models should be able to reproduce the true north-south gradient in CO2 due to the natural component before they can reliably estimate present-day CO2 sources and sinks and predict future atmospheric CO2. We have estimated the natural latitudinal distribution of atmospheric CO2, relative to the South Pole, using measurements of atmospheric CO2 during 1959-1991 and corresponding estimates of anthropogenic CO2 emissions to the atmosphere. Key features of the natural latitudinal distribution include: (1) CO2 concentrations in the northern hemisphere that are lower than those in the southern hemisphere; (2) CO2 concentration differences that are higher in the tropics (associated with outgassing of the oceans) than those currently measured; and (3) CO2 concentrations over the southern ocean that are relatively uniform. This natural latitudinal distribution and its sensitivity to increasing fossil fuel emissions both indicate that near-surface concentrations of atmospheric CO2 in the northern hemisphere are naturally lower than those in the southern hemisphere. Models that find the contrary will also mismatch present-day CO2 in the northern hemisphere and incorrectly ascribe that region as a large sink of anthropogenic CO2. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. CEA Saclay, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. RP Taylor, JA (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave,Bldg 221, Argonne, IL 60439 USA. RI Orr, James/C-5221-2009; Taylor, John/E-5894-2010; OI Taylor, John/0000-0001-9003-4076; Orr, James/0000-0002-8707-7080 NR 44 TC 13 Z9 13 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD DEC 15 PY 2000 VL 26 IS 4 BP 375 EP 386 DI 10.1016/S0921-8181(00)00050-3 PG 12 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 385WJ UT WOS:000166027900003 ER PT J AU Wang, ZM van de Burgt, LJ Choppin, GR AF Wang, ZM van de Burgt, LJ Choppin, GR TI Spectroscopic study of lanthanide(III) complexes with aliphatic dicarboxylic acids SO INORGANICA CHIMICA ACTA LA English DT Article DE lanthanide(II) complexes; aliphatic dicarboxylic acids; stability constants; luminescence spectra; complexation; absorption spectroscopy ID EXCITATION SPECTROSCOPY; STABILITY-CONSTANTS; LUMINESCENCE; EUROPIUM(III); ACTINIDES; CHLORIDE; NUMBER AB The complexation of trivalent lanthanides with aliphatic dicarboxylic acids (malonic, succinic, glutaric and adipic) were studied at 25 degreesC and 0.1 M (NaClO4) ionic strength by luminescence and absorption spectroscopy and luminescence lifetime measurements. The luminescence spectra and decay constants indicate that ML and ML2 complexes were formed. The stability constants of Eu(III) complexes with the dicarboxylic acids were calculated from the changes of the D-5(o)<-- F-7(o) excitation spectra of Eu(III). For the four dicarboxylic acids studied, both the stability constant and the number of water molecules released from the inner sphere of Eu(III) upon complexation decrease from malonate to adipate for both the ML and ML2 complexes. The results are interpreted as reflecting an increasing tendency from chelation to monodentation as the carbon chain length increases between carboxylate groups. The trend in the oscillator strength in the hypersensitive transition of the Nd(III)and Ho(III) complexes is the same as that in the ligand basicity. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Florida State Univ, Dept Chem, Tallahassee, FL 32306 USA. RP Wang, ZM (reprint author), Pacific NW Natl Lab, Mail Stop K8-96, Richland, WA 99352 USA. RI Wang, Zheming/E-8244-2010 OI Wang, Zheming/0000-0002-1986-4357 NR 32 TC 38 Z9 38 U1 2 U2 21 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD DEC 15 PY 2000 VL 310 IS 2 BP 248 EP 256 DI 10.1016/S0020-1693(00)00259-0 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 389RE UT WOS:000166250900019 ER PT J AU Anderson, ML Anderson, IE AF Anderson, ML Anderson, IE TI Gas atomization of metal hydrides for Ni-MH battery applications SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE metal hydride powders; gas atomization; electrochemical testing; annealing effects; gas phase hydrogen sorption ID ALLOYS; ELECTRODE AB The use of high Pressure gas atomization (HPGA) to produce fine, spherical powders of metal hydride (MH) alloys has been shown to improve the properties of the alloy, as well as reducing costly processing steps. Electrochemical cycling was used to compare three electrodes constructed of LaNi4.75Sn0.25 particulate, a simplified AB(5)-type alloy for battery applications. Two electrodes consisted of gas atomized powders and the other used particulate produced from casting and crushing an ingot, the conventional method of MH particulate production. Gas atomized powders showed improved cyclic stability over the cast and crushed particulate. A commercial cast and crushed MmNi(3.55)Co(0.75)Mn(0.4)Al(0.3), alloy was also cycled and showed reduced degradation when compared against the electrode composed of LaNi4.75Sn0.25 cast and crushed particulate, as was expected. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Iowa State Univ, Ames Lab, 126 Met Dev, Ames, IA 50011 USA. EM andersoni@ameslab.gov NR 18 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 EI 1873-4669 J9 J ALLOY COMPD JI J. Alloy. Compd. PD DEC 15 PY 2000 VL 313 BP 47 EP 52 DI 10.1016/S0925-8388(00)01170-1 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 389HY UT WOS:000166233600013 ER PT J AU Balema, VP Pecharsky, VK Dennis, KW AF Balema, VP Pecharsky, VK Dennis, KW TI Solid state phase transformations in LiAlH4 during high-energy ball-milling SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE lithium aluminum hydride; mechanochemistry; solid state catalysis ID SODIUM ALUMINUM-HYDRIDE; METAL HYDRIDES; MECHANOCHEMICAL ACTIVATION AB Mechanochemical processing of polycrystalline LiAlH4 revealed good stability of this complex aluminohydride during high-energy ball-milling in a helium atmosphere for up to 35 h. The decomposition of lithium aluminohydride into Li3AlH6, Al and H-2 is observed during prolonged mechanochemical treatment for up to 110 h and is most likely associated with the catalytic effect of a vial material, iron, which is introduced into the hydride as a contaminant during mechanical treatment. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Pecharsky, VK (reprint author), Iowa State Univ, Ames Lab, 242 Spedding Hall, Ames, IA 50011 USA. NR 25 TC 113 Z9 117 U1 2 U2 22 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD DEC 15 PY 2000 VL 313 BP 69 EP 74 DI 10.1016/S0925-8388(00)01201-9 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 389HY UT WOS:000166233600017 ER PT J AU Zeng, LM Franzen, HF AF Zeng, LM Franzen, HF TI Refinement of the crystal structure of Ge3Nd5 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE crystal structure; Ge3Nd5 compound AB The structure of Ge3Nd5 has been determined from single-crystal X-ray data. It crystallizes in the hexagonal, space group P6(3)/mcm (No.193) with the Mn5Si3 structure type and a=8.743(2) Angstrom, c=6.625(1) Angstrom, Z=2, v=438.56(17) Angstrom (3). (C) 2000 Elsevier Science BS. All rights reserved. C1 Guangxi Univ, Inst Sci Mat, Nanning 530004, Guangxi, Peoples R China. Iowa State Univ, Ames Lab, US DOE, Ames, IA 50011 USA. RP Zeng, LM (reprint author), Guangxi Univ, Inst Sci Mat, Nanning 530004, Guangxi, Peoples R China. NR 6 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD DEC 15 PY 2000 VL 313 BP 75 EP 76 DI 10.1016/S0925-8388(00)00923-3 PG 2 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 389HY UT WOS:000166233600018 ER PT J AU Seel, SC Thompson, CV Hearne, SJ Floro, JA AF Seel, SC Thompson, CV Hearne, SJ Floro, JA TI Tensile stress evolution during deposition of Volmer-Weber thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INTERNAL-STRESS; METAL-FILMS; INTRINSIC STRESS; POLYCRYSTALLINE; SURFACE; DEPENDENCE; GROWTH; COALESCENCE; NUCLEATION; DIFFUSION AB A simple model is presented that predicts the kinetics of tensile stress evolution during the deposition of thin films that grow by the Volmer-Weber mechanism. The generation of a tensile stress was attributed to the impingement and coalescence of growing islands, while concurrent stress relaxation was assumed to occur via a microstructure-dependent diffusive mechanism. To model the process of island coalescence, finite element methods were employed and yielded average tensile stresses more consistent with experimental observations than those predicted using previously reported analytical models. A computer simulation was developed that models the process of film growth as the continuous nucleation of isolated islands, which grow at a constant rate to impinge and coalesce to form a continuous polycrystalline film. By incorporating the finite element results for stress generation and a microstructure-dependent stress relaxation model, the simulation qualitatively reproduced the complex temperature-dependent trends observed from in situ measurements of stress evolution during the deposition of Ag thin films. The agreement includes simulation of the decreasing stress relaxation rate observed during deposition at increasing temperatures. (C) 2000 American Institute of Physics. [S0021-8979(01)01501-8]. C1 MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Seel, SC (reprint author), MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. NR 25 TC 114 Z9 114 U1 1 U2 33 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD DEC 15 PY 2000 VL 88 IS 12 BP 7079 EP 7088 DI 10.1063/1.1325379 PG 10 WC Physics, Applied SC Physics GA 377UD UT WOS:000165543900017 ER PT J AU Balcioglu, A Ahrenkiel, RK Hasoon, F AF Balcioglu, A Ahrenkiel, RK Hasoon, F TI Deep-level impurities in CdTe/CdS thin-film solar cells SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TRANSIENT SPECTROSCOPY; SEMICONDUCTORS; COPPER; TRAPS AB We have studied deep-level impurities in CdTe/CdS thin-film solar cells by capacitance-voltage (C-V), deep-level transient spectroscopy (DLTS), and optical DLTS (ODLTS). CdTe devices were grown by close-spaced sublimation. Using DLTS, a dominant electron trap and two hole traps were observed. These traps are designated as E1 at E-C-0.28 eV, H1 at E-V+0.34 eV, and H2 at E-V+0.45 eV. The presence of the E1 and H1 trap levels was confirmed by ODLTS. The H1 trap level is due to Cu-induced substitutional defects. The E1 trap level is believed to be a deep donor and is attributed to the doubly ionized interstitial Cu or a Cu complex. The E1 trap is an effective recombination center and is a lifetime killer. (C) 2000 American Institute of Physics. [S0021- 8979(00)02701-3]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Balcioglu, A (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. NR 20 TC 42 Z9 44 U1 4 U2 36 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD DEC 15 PY 2000 VL 88 IS 12 BP 7175 EP 7178 DI 10.1063/1.1326465 PG 4 WC Physics, Applied SC Physics GA 377UD UT WOS:000165543900033 ER PT J AU Cooke, DW McClellan, KJ Bennett, BL Roper, JM Whittaker, MT Muenchausen, RE Sze, RC AF Cooke, DW McClellan, KJ Bennett, BL Roper, JM Whittaker, MT Muenchausen, RE Sze, RC TI Crystal growth and optical characterization of cerium-doped Lu1.8Y0.2SiO5 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RARE-EARTH; CZOCHRALSKI GROWTH; OXYORTHOSILICATES; SCINTILLATORS AB Czochralski growth of cerium-doped Lu1.8Y0.2SiO5 (LYSO) from a 90/10 solution of Lu2SiO5 (LSO) and Y2SiO5 (YSO) is demonstrated. The alloyed scintillator retains the favorable growth properties of YSO and the desirable physical and optical scintillator properties of LSO. Radioluminescence, thermally stimulated luminescence, optical absorption, and lifetime measurements confirm the equivalence of LYSO and LSO optical properties. Advantages of LYSO Czochralski growth relative to LSO include reduced melting point, less propensity for formation of crystalline inclusions, lower cost of starting material, and easier incorporation of cerium into the host lattice. This material offers an attractive alternative to LSO for scintillator applications. (C) 2000 American Institute of Physics. [S0021-8979(00)08201-9]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Cooke, DW (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. NR 6 TC 146 Z9 149 U1 3 U2 28 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD DEC 15 PY 2000 VL 88 IS 12 BP 7360 EP 7362 DI 10.1063/1.1328775 PG 3 WC Physics, Applied SC Physics GA 377UD UT WOS:000165543900064 ER PT J AU Minambres, B Olivera, ER Jensen, RA Luengo, JM AF Minambres, B Olivera, ER Jensen, RA Luengo, JM TI A new class of glutamate dehydrogenases (GDH) - Biochemical and genetic characterization of the first member, the AMP-requiring NAD-specific GDH of Streptomyces clavuligerus SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID BETA-LACTAM; CEPHALOSPORIN PRODUCTION; PYROCOCCUS-FURIOSUS; SEQUENCE ALIGNMENT; CLAVULANIC ACID; PURIFICATION; ENZYME; EVOLUTION; SYNTHETASE; MECHANISM AB A new class of glutamate dehydrogenase (GDH) is reported. The GDH of Streptomyces clavuligerus was purified to homogeneity and characterized. It has a native molecular mass of 1,100 kDa and exists as an alpha (6) oligomeric structure composed of 183-kDa subunits, GDH, which requires AMP as an essential activator, shows a maximal rate of catalysis in 100 mM phosphate buffer, pH 7.0, at 30 degreesC. Under these conditions, GDH displayed hyperbolic behavior toward ammonia (K-m, 33 mM) and sigmoidal responses to changes in alpha -ketoglutarate (S-0.5 1.3 mM; n(H) 1.50) and NADH (S-0.5 20 mum; n(H) 1.52) concentrations. Aspartate and asparagine were found to be allosteric activators. This enzyme is inhibited by an excess of NADH or NH4+, by some tricarboxylic acid cycle intermediates and by ATP, This GDH seems to be a catabolic enzyme as indicated by the following: (i) it is NAD-specific; (ii) it shows a high value of K-m for ammonia; and (iii) when S. clavuligerus was cultured in minimal medium containing glutamate as the sole source of carbon and nitrogen, a 5-fold increase in specific activity of GDH was detected compared with cultures provided with glycerol and ammonia. GDH has 1,651 amino acids, and it is encoded by a DNA fragment of 4,953 base pairs (gdh gene), It shows strong sequence similarity to proteins encoded by unidentified open reading frames present in the genomes of species belonging to the genera Mycobacterium, Rickettsia, Pseudomonas, Vibrio, Shewanella, and Caulobacter, suggesting that it has a broad distribution. The GDH of S, clavuligerus is the first member of a class of GDHs included in a subfamily of GDHs (large GDHs) whose catalytic requirements and evolutionary implications are described and discussed. C1 Univ Leon, Dept Bioquim & Biol Mol, Fac Vet, E-24007 Leon, Spain. Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. RP Luengo, JM (reprint author), Univ Leon, Dept Bioquim & Biol Mol, Fac Vet, E-24007 Leon, Spain. RI RODRIGUEZ OLIVERA, ELIAS/H-6385-2016 OI RODRIGUEZ OLIVERA, ELIAS/0000-0003-2315-8524 NR 71 TC 45 Z9 47 U1 0 U2 2 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD DEC 15 PY 2000 VL 275 IS 50 BP 39529 EP 39542 DI 10.1074/jbc.M005136200 PG 14 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 384PB UT WOS:000165953100080 PM 10924516 ER PT J AU Larrimore, L McFarland, RN Sterne, PA Bug, ALR AF Larrimore, L McFarland, RN Sterne, PA Bug, ALR TI A two-chain path integral model of positronium SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MONTE-CARLO SIMULATIONS; SEMICONDUCTOR QUANTUM DOTS; MOLECULAR-DYNAMICS; HARD-SPHERE; BOUNDARY-CONDITIONS; ANNIHILATION; ZEOLITES; SYSTEMS; HELIUM; FLUIDS AB We have used a path integral Monte Carlo technique to simulate positronium (Ps) in a cavity. The primitive propagator is used, with a pair of interacting chains representing the positron and electron. We calculate the energy and radial distribution function for Ps enclosed in a hard, spherical cavity, and the polarizability of the model Ps in the presence of an electrostatic field. We find that the positron distribution near the hard wall differs significantly from that for a single particle in a hard cavity. This leads to systematic deviations from predictions of free-volume models which treat Ps as an effective, single particle. A virial-type estimator is used to calculate the kinetic energy of the particle in the presence of hard walls. This estimator is found to be superior to a kinetic-type estimator given the interaction potentials, cavity sizes, and chain lengths considered in the current study. (C) 2000 American Institute of Physics. [S0021-9606(00)50447-4]. C1 Swarthmore Coll, Dept Phys & Astron, Swarthmore, PA 19081 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Bug, ALR (reprint author), Swarthmore Coll, Dept Phys & Astron, Swarthmore, PA 19081 USA. NR 68 TC 15 Z9 15 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 15 PY 2000 VL 113 IS 23 BP 10642 EP 10650 AR PII [S0021-9606(00)50447-4] DI 10.1063/1.1323979 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LC UT WOS:000165585000020 ER PT J AU Siu, WK Bartynski, RA Hulbert, SL AF Siu, WK Bartynski, RA Hulbert, SL TI The role of defects at low concentrations in the NH3/TiO2(110) adsorption system: An Auger-photoelectron coincidence spectroscopy study SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; TIO2(110) SURFACE; SYNCHROTRON RADIATION; INVERSE-PHOTOEMISSION; CHEMISORBED PHASES; INTRINSIC DEFECTS; OXYGEN; TIO2; PERFECT; SRTIO3 AB We present Auger-photoelectron coincidence spectra from the stoichiometric and reduced (by vacuum annealing) TiO2(110) surfaces after saturation exposure to NH3 at room temperature. The Ti 3p coincidence photoemission spectrum shows substantial emission from residual (or intrinsic) defects on the stoichiometric surface and additional emission from thermally-induced bridging oxygen vacancies on the reduced surface. Changes in the line shape of the coincidence Ti 3p spectrum upon adsorption show that NH3 binds to the five-fold coordinated Ti ions and the rosette structures of both surfaces, and at bridging oxygen vacancies of the reduced surface, but not at intrinsic defects. Quantitative analysis of the spectra supports a structural model where on the stoichiometric surface NH3 adsorbs at every other five-fold coordinated Ti site and at every other Ti site of the rosettes. On the reduced surface, NH3 adsorbs at bridging oxygen vacancies preventing adsorption on neighboring five-fold coordinated Ti sites, suggesting that the saturation coverage of NH3 is smaller for the reduced surface. We observe a correlation between the density of bridging oxygen vacancies and the coincidence intensity from five-fold coordinated Ti ions that gives an internally consistent account of these data. (C) 2000 American Institute of Physics. [S0021-9606(00)70447-8]. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08855 USA. Rutgers State Univ, Surface Modificat Lab, Piscataway, NJ 08855 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11972 USA. RP Siu, WK (reprint author), Rutgers State Univ, Dept Phys & Astron, 136 Frelinghuysen Rd, Piscataway, NJ 08855 USA. NR 31 TC 15 Z9 15 U1 0 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 15 PY 2000 VL 113 IS 23 BP 10697 EP 10702 DI 10.1063/1.1323726 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LC UT WOS:000165585000026 ER PT J AU Shkrob, IA Tarasov, VF AF Shkrob, IA Tarasov, VF TI On the structure of trapped holes in borosilicates SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ECHO ENVELOPE MODULATION; ELECTRON-SPIN-RESONANCE; DEFECT CENTERS; FOURIER-TRANSFORM; EPR SPECTROSCOPY; GLASS; DANBURITE; CRYSTALS; WASTE; ENDOR AB Danburite (CaB2Si2O8) is a naturally occurring borosilicate mineral that is a crystalline analog of borosilicate glass. Using two-dimensional correlation electron spin echo envelope modulation spectroscopy, we determined the structure of the prevalent radiation-induced defect, boron oxygen hole center, in this mineral. The hole is trapped by nonbridging oxygen in a strongly distorted -O3B-O--BO3- linkage; the precursor of the hole center is a Ca2+ vacancy. These results and computer modeling suggest that in borosilicate glasses, the hole center is the same >B-O-. radical as in alkali borate glasses. We suggest that a >B-O- unit near a cation vacancy is the precursor of hole centers in both types of glasses. (C) 2000 American Institute of Physics. [S0021-9606(00)71347-X]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Shkrob, IA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 31 TC 14 Z9 14 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 15 PY 2000 VL 113 IS 23 BP 10723 EP 10732 DI 10.1063/1.1323960 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LC UT WOS:000165585000030 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Influence of the modification conditions of alkyl bonded ligands on the characteristics of reversed-phase liquid chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE stationary phases, LC; thermodynamic parameters; mass transfer; retention behavior; heat of absorption; surface diffusion; absorption ID ENTHALPY-ENTROPY COMPENSATION; ADSORPTION CHARACTERISTICS; PERFORMANCE; BEHAVIOR; RETENTION; TEMPERATURE; SOLVENT AB The parameters characterizing retention and the mass transfer mechanisms in reversed-phase liquid chromatography were derived from data acquired for a series of compounds on a silica gel bonded to alkyl ligands of various lengths and Ligand densities. The adsorption equilibrium constant, the absolute value of the isosteric heat of adsorption, and the activation energy of surface diffusion increase while the surface diffusion coefficient decreases with increasing length of the alkyl chain and density of the C-18 ligand. These results are consistent with increasing restriction of the mobility of an increasingly adsorbable molecule. There is a critical level of carbon content above which the four parameters just listed no longer change with increasing alkyl ligand density. This level is likely to depend on the sizes of the alkyl ligand and the sample molecule. Even at high densities of C-18 chains, there may be a limitation in the contact area of the sample molecule and the alkyl ligand, The retention behavior on the stationary phases studied is explained by assuming that the sample molecules penetrate into the layer of alkyl ligands. Enthalpy-entropy compensation was demonstrated for surface diffusion. Its mechanism is probably similar on the different stationary phases studied, irrespective of the length and density of the bonded ligand. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 34 TC 36 Z9 37 U1 1 U2 8 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 DEC 15 PY 2000 VL 903 IS 1-2 BP 1 EP 12 DI 10.1016/S0021-9673(00)00891-8 PG 12 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 384ZU UT WOS:000165977800001 PM 11153934 ER PT J AU Robbins, JA Holmes, C Halley, R Bothner, M Shinn, E Graney, J Keeler, G tenBrink, M Orlandini, KA Rudnick, D AF Robbins, JA Holmes, C Halley, R Bothner, M Shinn, E Graney, J Keeler, G tenBrink, M Orlandini, KA Rudnick, D TI Time-averaged fluxes of lead and fallout radionuclides to sediments in Florida Bay SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID UNITED-STATES; CS-137; PLUTONIUM; MOBILITY; PB-210; PU; DIAGENESIS; TRANSPORT; GASOLINE; PU-239,PU-240 AB Recent, unmixed sediments from mud banks of central Florida Bay were dated using Pb-210/Ra-226, and chronologies were verified by comparing sediment lead temporal records with Pb/Ca ratios in annual layers of coral (Montastrea annularis) located on the ocean side of the Florida Keys. Dates of sediment lead peaks (1978 +/- 2) accord with prior observations of a 6 year lag between the occurrence of maximum atmospheric lead in 1972 and peak coral lead in 1978. Smaller lags of 1-2 years occur between the maximum atmospheric radionuclide fallout and peaks in sediment temporal records of Cs-137 and Pu. Such lags are consequences of system time averaging (STA) in which atmospherically delivered particle-associated constituents accumulate and mix in a (sedimentary?) reservoir before transferring to permanent sediments and coral. STA model calculations, using time-dependent atmospheric inputs, produced optimized profiles in excellent accord with measured sediment 137Cs, Pu, lead, and coral lead distributions. Derived residence times of these particle tracers (16 +/- 1, 15.7 +/- 0.7, 19 +/- 3, and 16 +/- 2 years, respectively) are comparable despite differences in sampling locations, in accumulating media, and in element loading histories and geochemical properties. For a 16 year weighted mean residence time, STA generates the observed 6 year lead peak lag. Evidently, significant levels of nondegradable, particle-associated contaminants can persist in Florida Bay for many decades following elimination of external inputs. Present results, in combination with STA model analysis of previously reported radionuclide profiles, suggest that decade-scale time averaging may occur widely in recent coastal marine sedimentary environments. C1 NOAA, Great Lakes Environm Res Lab, US Dept Commerce, Ann Arbor, MI 48105 USA. US Geol Survey, Ctr Coastal & Reg Marine Geol, St Petersburg, FL 33701 USA. US Geol Survey, Woods Hole Field Ctr, Marine & Coastal Program, Woods Hole, MA 02543 USA. Univ Michigan, Dept Environm & Ind Hlth, Sch Publ Hlth, Ann Arbor, MI 48109 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. S Florida Water Management Dist, W Palm Beach, FL 33146 USA. RP Robbins, JA (reprint author), NOAA, Great Lakes Environm Res Lab, US Dept Commerce, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. NR 71 TC 39 Z9 39 U1 3 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD DEC 15 PY 2000 VL 105 IS C12 BP 28805 EP 28821 DI 10.1029/1999JC000271 PG 17 WC Oceanography SC Oceanography GA 388XR UT WOS:000166208800019 ER PT J AU Zlotin, SG Kislitsin, PG Samet, AV Serebryakov, EA Konyushkin, LD Semenov, VV Buchanan, AC Gakh, AA AF Zlotin, SG Kislitsin, PG Samet, AV Serebryakov, EA Konyushkin, LD Semenov, VV Buchanan, AC Gakh, AA TI Synthetic utilization of polynitroaromatic compounds. 1. S-derivatization of 1-substituted 2,4,6-trinitrobenzenes with thiols SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID NITRO-GROUPS; DISPLACEMENT; 1,3,5-TRINITROBENZENE; ESTERS AB Reactions of 1-R-2,4,6-trinitrobenenes (R = alkyl, protected aldehyde, aminocarbonyl, cyano groups, or isoxazole ring) with thiol salts were investigated. In most cases, these reactions gave a mixture of minor para and major ortho substitution products. Reactions of N,N-disubstituted 2,4,6-trinitrobenzamides with S-,O-, and N-nucleophiles afforded products of substitution of the p-nitro group exclusively. 1-Cyano-2,4,6-trinitrobenzene was found to be the most reactive and the least selective: all three nitro groups can be substituted using an excess;of thiol salts. 2-R-4,6-dinitrobenzamides showed no regioselectivity under similar conditions to yield 1:1 mixtures of para and ortho isomers. C1 RAS, ND Zelinskii Organ Chem Inst, Moscow 117913, Russia. Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. RP Zlotin, SG (reprint author), RAS, ND Zelinskii Organ Chem Inst, Leninsky Pr 47, Moscow 117913, Russia. NR 18 TC 30 Z9 30 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD DEC 15 PY 2000 VL 65 IS 25 BP 8430 EP 8438 PG 9 WC Chemistry, Organic SC Chemistry GA 381FQ UT WOS:000165752000004 PM 11112559 ER PT J AU Zlotin, SG Kislitsin, PG Podgursky, AI Samet, AV Semenov, VV Buchanan, AC Gakh, AA AF Zlotin, SG Kislitsin, PG Podgursky, AI Samet, AV Semenov, VV Buchanan, AC Gakh, AA TI Synthetic utilization of polynitroaromatic compounds. 2. Synthesis of 4,6-dinitro-1,2-benzisothiazol-3-ones and 4,6-dinitro-1,2-benzisothiazoles from 2-benzylthio-4,6-dinitrobenzamides SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID 1,2-BENZISOTHIAZOLE DERIVATIVES AB Cyclization of 2-benzylthio-4,6-dinitrobenzamides to 4,6-dinitro-1,2-benzisothiazol-3-ones was achieved using SO2Cl2 in CH2Cl2 at room temperature. Alkylation of these heterocycles proceeded in a nonregioselective manner to yield st mixture of corresponding O- and N-alkylated products. Oxidation of 4,6-dinitro-1,2-benzisothiazoles (50% H2O2 in AcOH) afforded the corresponding S-oxides ana S,S-dioxides, depending on oxidation conditions. Unexpectedly, oxidation of a 3-methoxy derivative resulted iri: ring opening with the formation of the corresponding sulfamide, Chlorination of these 4,6-dinitro-1,2-benzisothiazol-3-ones (PCl5-POCl3) gave the expected 3-chloroisothiazoles. C1 RAS, ND Zelinskii Organ Chem Inst, Moscow 117913, Russia. Oak Ridge Natl Lab, Chem & Analyt Sci Div, Oak Ridge, TN 37831 USA. RP Zlotin, SG (reprint author), RAS, ND Zelinskii Organ Chem Inst, Leninsky Pr 47, Moscow 117913, Russia. NR 24 TC 27 Z9 28 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD DEC 15 PY 2000 VL 65 IS 25 BP 8439 EP 8443 DI 10.1021/jo000480c PG 5 WC Chemistry, Organic SC Chemistry GA 381FQ UT WOS:000165752000005 PM 11112560 ER PT J AU Fisher, IR Kramer, MJ Islam, Z Wiener, TA Kracher, A Ross, AR Lograsso, TA Goldman, AI Canfield, PC AF Fisher, IR Kramer, MJ Islam, Z Wiener, TA Kracher, A Ross, AR Lograsso, TA Goldman, AI Canfield, PC TI Growth of large single-grain quasicrystals from high-temperature metallic solutions SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystal; crystal-growth; flux-growth ID ICOSAHEDRAL QUASI-CRYSTALS; AL-NI-CO; R = Y; TERNARY MELT; MG-ZN; PHASE-DIAGRAM; HO; TB; SYSTEM; RANGE AB Flux-growth techniques have been successfully applied to the preparation of several families of quasicrystals and related approximant phases. Large (up to 1 cm(3)) single-grain samples have been obtained for icosahedral R-Mg-Zn (R=Y, Gd, Tb, Dy, Ho and Er), decagonal Al-Ni-Co, icosahedral Al-Pd-Mn, icosahedral Al-Ga-Pd-Mn, and the xi' Al-Pd-Mn approximant phase. The samples are obtained by slowly cooling ternary (or quaternary) melts of a composition that intersects the primary solidification surface of the desired phase in the equilibrium ternary alloy phase diagram (i.e. this is a self-flux technique). The technique clearly reveals the growth habit, and results in remarkably strain-free quasicrystals. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Geol & Atmospher Sci, Ames, IA 50011 USA. RP Fisher, IR (reprint author), Stanford Univ, LAM, Stanford, CA 94305 USA. RI Canfield, Paul/H-2698-2014 NR 21 TC 24 Z9 24 U1 1 U2 13 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 10 EP 16 DI 10.1016/S0921-5093(00)01323-X PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900003 ER PT J AU Ross, AR Wiener, TA Fisher, IR Canfield, PC Lograsso, TA AF Ross, AR Wiener, TA Fisher, IR Canfield, PC Lograsso, TA TI Formation and morphological development of porosity in icosahedral Al-Pd-Mn alloys SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasi-crystal; Al-Fd-Mn; porosity; faceting ID QUASI-CRYSTALS AB Directional solidification and quenching experiments have been conducted to examine the formation and origin of the faceted porosity commonly observed in icosahedral Al-Pd-Mn alloys. Faceted porosity has been previously observed in both Czochralski grown and Bridgman grown single crystals during single-phase solidification of the icosahedral phase. Detailed observations in Bridgman grown single crystals indicate that the distribution and quantity of pores are non-uniformly distributed along the length of the as-grown ingot. This non-uniform distribution suggests that their formation is influenced by both chemical segregation during solidification as well as convection in the liquid. Controlled solidification of this alloy followed by quenching of the solid-liquid interface provides for a time-temperature history of the porosity formation and morphological development as a function of processing conditions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Lograsso, TA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 8 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 53 EP 56 DI 10.1016/S0921-5093(00)01169-2 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900012 ER PT J AU Brunet, P Zhang, LM Sordelet, DJ Besser, M Dubois, JM AF Brunet, P Zhang, LM Sordelet, DJ Besser, M Dubois, JM TI Comparative study of microstructural and tribological properties of sintered, bulk icosahedral samples SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE sintering; hardness; friction coefficient; wear resistance ID BEHAVIOR; COATINGS; FE AB We have investigated a number of quasicrystalline and related samples prepared by sintering under either hot isostatic pressure (HIP) or low uniaxial pressure (LUP). Attention was focused to the influence of the preparation process parameters onto the resulting crystallographic structure and morphology of the phases. Altogether, we found some differences between the two kinds of samples as far as hardness and friction coefficient were concerned. For instance, HIPed specimens containing boron exhibited small rod-shaped precipitates whereas LUPed samples did not. The LUPed specimens revealed better wear resistance and lower friction towards steel and tungsten carbide riders than the HIPed materials. The present study clearly points out that pressure-temperature-composition phase diagrams and preparation processes of quasicrystals, as well as for most other materials, have a significant influence on the final properties which may be eventually used in view of technological applications. (C) 2000 Elsevier Science B.V. All rights reserved. C1 INPL, UMR 7584 CNRS, LSG2M, F-54042 Nancy, France. GDR CINQ, F-54042 Nancy, France. Dalian Univ Technol, Dept Mat Engn, Dalian 116023, Peoples R China. Ames Lab, Ames, IA 50011 USA. RP Brunet, P (reprint author), INPL, UMR 7584 CNRS, LSG2M, Parc Saurupt, F-54042 Nancy, France. NR 6 TC 47 Z9 48 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 74 EP 78 DI 10.1016/S0921-5093(00)01202-8 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900017 ER PT J AU Letoublon, A Fisher, IR Sato, TJ de Boissieu, M Boudard, M Agliozzo, S Mancini, L Gastaldi, J Canfield, PC Goldman, AI Tsai, AP AF Letoublon, A Fisher, IR Sato, TJ de Boissieu, M Boudard, M Agliozzo, S Mancini, L Gastaldi, J Canfield, PC Goldman, AI Tsai, AP TI Phason strain and structural perfection in the Zn-Mg-rare-earth icosahedral phases SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystal; rare earth; phason strain ID R = Y; QUASI-CRYSTALS; HO; ALLOYS; ER; DY; TB AB The structural perfection of eight samples of icosahedral Zn-Mg-R (R=Y, Ho and Tb) single grains has been studied by high resolution X-ray diffraction, Four samples present a systematic peak shift proportional to Q(per) characteristic of a linear phason strain. Two other samples present a peak splitting proportional to Q(per). Only two samples had their Bragg peak position corresponding to the ideal one, with a width increasing linearly with Q(per). The perfection of one of these last two samples was investigated by synchrotron monochromatic X-ray topography. It was found to be a microstructure similar to the one exhibited by conventional crystals grown by the same technique (flux-growth). (C) 2000 Elsevier Science B.V. All rights reserved. C1 LTPC, INPG, UMR CNRS 5614, F-38402 St Martin Dheres, France. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Natl Res Inst Met, Tsukuba, Ibaraki 3050047, Japan. European Synchrotron Radiat Facil, F-38043 Grenoble, France. CNRS, CRMC2, F-13288 Marseille, France. RP de Boissieu, M (reprint author), LTPC, INPG, UMR CNRS 5614, BP 75, F-38402 St Martin Dheres, France. RI Canfield, Paul/H-2698-2014; Sato, Taku/I-7664-2015; OI Sato, Taku/0000-0003-2511-4998; Mancini, Lucia/0000-0003-2416-3464 NR 15 TC 13 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 127 EP 130 DI 10.1016/S0921-5093(00)01085-6 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900030 ER PT J AU Yan, YF Pennycook, SJ AF Yan, YF Pennycook, SJ TI Z-contrast imaging of decagonal quasicrystals: an atomistic model of growth SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE Z-contrast imaging; decagonal quasicrystal; Al72Ni20Co8; rotational ordering ID QUASI-CRYSTALS; STRUCTURAL-CHANGE; AL65CU20CO15; SYMMETRY; PHASE AB The structure of Al-Ni-Co decagonal quasicrystals is studied by atomic-resolution Z-contrast imaging technique. We propose that the presence of "rotational ordering" is the key reason leading to the formation of the 2 nm clusters and the overlaps necessary in the coverage model. Every detail of the Z-contrast images of the 2 nm clusters can be reproduced by a superposition of rotational variants of the 2 nm clusters seen in the ordered tau (2)-inflated Al13Co4 approximant phase. introducing this rotational ordering, it is clear how one cluster can nucleate neighboring clusters. Continuing this process automatically generates all the intercluster separations necessary for quasiperiodic tiling. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Yan, YF (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 22 TC 2 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 211 EP 216 DI 10.1016/S0921-5093(00)01309-5 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900047 ER PT J AU Abe, H Tamura, N Le Bolloc'h, D Moss, SC Matsuo, Y Ishii, Y Bai, JM AF Abe, H Tamura, N Le Bolloc'h, D Moss, SC Matsuo, Y Ishii, Y Bai, JM TI Anomalous-X-ray scattering associated with short-range order in an Al70Ni15Co15 decagonal quasicrystal SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE short-range order; phason; anomalous-X-ray scattering; decagonal quasicrystal ID AL-NI-CO; QUASI-CRYSTAL; DIFFRACTION; TEMPERATURE AB The diffuse scattering around Bragg reflections was observed in a single decagonal quasicrystal of Al70Ni15Co15 using anomalous-X-ray scattering. The intensities of diffuse scattering vary with the three incident X-ray wavelengths, near the Co K-edge and the Ni K-edge and between them. The contrast of diffuse scattering shows the existence of atomic short-range order (SRO) between Ni and Co. The distributions of diffuse scattering are anisotropically modulated and the diffuse shapes vary from one reciprocal lattice point to another. in quasicrystals, anisotropic diffuse shapes derive from phason strain. It is concluded that both SRO and phason strains exist in Al70Ni15Co15. in addition, as the first neighbor of Ni, Ni is preferred to Co statistically, since SRO intensities appear about zone-centers, i.e. there is local clustering of these species. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Def Acad, Dept Mat Sci & Engn, Yokosuka, Kanagawa 2398686, Japan. Univ Houston, Dept Phys, Houston, TX 77204 USA. Nara Womens Univ, Dept Phys, Nara 6308263, Japan. Chuo Univ, Dept Phys, Tokyo 1128551, Japan. Oak Ridge Associated Univ, Oak Ridge, TN 37831 USA. RP Abe, H (reprint author), Natl Def Acad, Dept Mat Sci & Engn, Yokosuka, Kanagawa 2398686, Japan. RI Bai, Jianming/O-5005-2015 NR 12 TC 10 Z9 10 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 299 EP 302 DI 10.1016/S0921-5093(00)01102-3 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900068 ER PT J AU Belin-Ferre, E Fournee, V Mizutani, U Takeuchi, T Muller, H AF Belin-Ferre, E Fournee, V Mizutani, U Takeuchi, T Muller, H TI Investigation of Al and Mg occupied densities of states of Al-Mg-Zn alloys SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE electronic structure; quasicrystals; approximants; X-ray spectroscopy ID ELECTRONIC-STRUCTURE AB In this paper we report first results on the investigation of the electronic distributions in a series of Al-Mg-Zn alloys by means of X-ray emission spectroscopy. This technique was selected as it allows to probe separately partial densities of states around each constituent in a compound. Differences are observed in the shapes and energy extent of the partial spectral curves from quasicristalline to 1/1- and 2/1-approximants in this system. This indicates modifications in the electronic interactions according to the atomic structure of the specimen. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Lab Chime Phys Mat & Rayonnement, UMR 7614, F-75231 Paris 05, France. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Nagoya Univ, Dept Crystalline Mat Sci, Nagoya, Aichi 46401, Japan. Vienna Tech Univ, Inst Expt Phys, A-1040 Vienna, Austria. RP Belin-Ferre, E (reprint author), Lab Chime Phys Mat & Rayonnement, UMR 7614, 11 Rue Pierre & Marie Curie, F-75231 Paris 05, France. NR 2 TC 2 Z9 2 U1 1 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 516 EP 518 DI 10.1016/S0921-5093(00)01327-7 PG 3 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900117 ER PT J AU Grimm, U Romer, RA Schreiber, M Zhong, JX AF Grimm, U Romer, RA Schreiber, M Zhong, JX TI Universal level-spacing statistics in quasiperiodic tight-binding models SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystals; electronic properties; tight-binding model; multifractality; energy-level statistics; random matrix theory ID METAL-INSULATOR-TRANSITION; DISORDERED-SYSTEMS; ANDERSON TRANSITION; QUASI-CRYSTAL; DISTRIBUTIONS; ASYMPTOTICS AB We studied statistical properties of the energy spectra of two-dimensional quasiperiodic tight-binding models. The multifractal nature of the eigenstates of these models is corroborated by the scaling of the participation numbers with the system size. Hence one might have expected 'critical' or 'intermediate' statistics for the level-spacing distributions as observed at the metal-insulator transition in the three-dimensional Anderson model of disorder. However, our numerical results are in perfect agreement with the universal level-spacing distributions of the Gaussian orthogonal random matrix ensemble, including the distribution of spacings between second, third, and fourth neighbour energy levels. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tech Univ Chemnitz, Inst Phys, D-09107 Chemnitz, Germany. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Xiangtan Univ, Dept Phys, Xiangtan 411105, Peoples R China. RP Grimm, U (reprint author), Tech Univ Chemnitz, Inst Phys, D-09107 Chemnitz, Germany. RI Grimm, Uwe/E-5351-2010; Roemer, Rudolf/B-3036-2010; Roemer, Rudolf/D-7427-2016 OI Grimm, Uwe/0000-0001-5492-7467; Roemer, Rudolf/0000-0002-0244-7864; Roemer, Rudolf/0000-0002-0244-7864 NR 23 TC 3 Z9 3 U1 2 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 564 EP 567 DI 10.1016/S0921-5093(00)01173-4 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900129 ER PT J AU Khoukaz, C Galler, R Mehrer, H Canfield, PC Fisher, IR Feuerbacher, M AF Khoukaz, C Galler, R Mehrer, H Canfield, PC Fisher, IR Feuerbacher, M TI Diffusion of Co-57 in decagonal Al-Ni-Co-quasicrystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE diffusion; decagonal Al-Ni-Co; radiotracer method; anisotropy of diffusion ID SELF-DIFFUSION; POSITRON-ANNIHILATION; PRESSURE-DEPENDENCE; TEMPERATURE; MN-54; FE-59; PHASE AB Self-diffusion of Co-57 in decagonal Al-Ni-Co single quasicrystals was studied for both principal directions as a function of the temperature by means of the radiotracer method. In combination with serial sectioning, diffusivities were measured over a large temperature range from 732 to 1273 K. Below about 1120 K diffusion is described by an Arrhenius behaviour along both the periodic and the quasiperiodic directions. The magnitude of the activation enthalpies and pre-exponential factors support a vacancy-type diffusion mechanism. A small anisotropy of diffusion which is temperature-dependent but never exceeds 30% was detected. Above 1120 K, a kink in the Arrhenius curve is observed. We attribute this behaviour to a phase transition from the decagonal basic Go-rich phase to an ordered modification. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Munster, Inst Met Forsch, D-48149 Munster, Germany. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. RP Khoukaz, C (reprint author), Univ Munster, Inst Met Forsch, Wilhelm Klemm Str 10, D-48149 Munster, Germany. EM khoukac@nwz.uni-muenster.de RI Feuerbacher, Michael/K-3768-2013; Canfield, Paul/H-2698-2014 OI Feuerbacher, Michael/0000-0003-2882-4960; NR 26 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 697 EP 701 DI 10.1016/S0921-5093(00)01149-7 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900162 ER PT J AU Gianno, K Sologubenko, AV Chernikov, MA Ott, HR Fisher, IR Canfield, PC AF Gianno, K Sologubenko, AV Chernikov, MA Ott, HR Fisher, IR Canfield, PC TI Electrical resistivity, thermopower, and thermal conductivity of single grained (Y, Tb, Ho, Er)-Mg-Zn icosahedral quasicrystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE icosahedral; quasicrystal; thermal conductivity; thermopower; electrical conductivity ID ZN-MG-Y; R = Y; QUASI-CRYSTALS; TRANSPORT; GROWTH; ER; DY AB We report on measurements of the temperature dependence of the electrical resistivity rho, the thermopower S, and the thermal conductivity lambda of single grained RE-Mg-Zn (RE=Y, Tb, Ho, Er) icosahedral quasicrystals between 5 acid 300 K. The resistivity of all four samples is very weakly temperature dependent with a negative slope d rho /dT. The S/T versus temperature curves exhibit a maximum at temperatures between 12 and 15 K. This feature is observed for all here investigated quasicrystalline materials. The appearance of a maximum in the thermal conductivity of (Y, Ho, Er)-Mg-Zn, and a plateau in that of Tb-Mg-Zn is ascribed to a power-law temperature dependence of the mean free path of delocalized quasilattice excitations at intermediate temperatures. A progressive suppression of the maximum in the thermal conductivity data as the de Gennes factor increases indicates for a coupling of the spin system to the lattice. (C) 2000 Elsevier Science B.V. All rights reserved. C1 ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Ott, HR (reprint author), ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland. RI Canfield, Paul/H-2698-2014 NR 16 TC 26 Z9 26 U1 0 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 715 EP 718 DI 10.1016/S0921-5093(00)01057-1 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900166 ER PT J AU Inaba, A Takakura, H Tsai, AP Fisher, IR Canfield, PC AF Inaba, A Takakura, H Tsai, AP Fisher, IR Canfield, PC TI Heat capacities of icosahedral and hexagonal phases of Zn-Mg-Y system SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE Zn-Mg-Y alloys; quasicrystals; icosahedral phases; heat capacity; lattice vibrations; vibrational density of states ID RARE-EARTH ALLOYS; AL-CU-RU; QUASI-CRYSTALS AB Heat capacity measurements have been performed in the temperature range 4-300 K for an icosahedral phase of Zn-Mg-Y alloy (Zn55Mg35Y10) and the related crystalline phases, a hexagonal phase (Zn65.2Mg27.9Y6.9) and the Laves phase of MgZn2, to study the feature of lattice vibrations in quasicrystals. A single quasicrystal of Zn56.8Mg34.6Y8.7 was also investigated for comparison. The vibrational density of states is delineated in terms of the temperature dependence of the apparent Debye temperature (Theta (D)) on a reduced basis using the limiting value at high temperature (Theta (infinity)). A deeper minimum (Theta (D)/Theta (infinity)similar to0.82) is observed at substantially lower temperatures (T/Theta (infinity)similar to0.055) in the quasicrystals than in the crystals, which suggests significant enhancement of the density of states at the corresponding energies. The fact is compatible to that obtained previously for Al-Cu-Ru, Al-Pd-Re and Al-Pd-Mn systems. The presence of some defects or inhomogeneity in quasicrystals might be responsible for the anharmonic lattice vibrations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Osaka Univ, Grad Sch Sci, Dept Chem, Toyonaka, Osaka 5600043, Japan. Osaka Univ, Grad Sch Sci, Res Ctr Mol Thermodynam, Toyonaka, Osaka 5600043, Japan. Japan Sci & Technol Corp, CREST, Tsukuba, Ibaraki 3050047, Japan. Natl Res Inst Met, Tsukuba, Ibaraki 3050047, Japan. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Inaba, A (reprint author), Osaka Univ, Grad Sch Sci, Dept Chem, Toyonaka, Osaka 5600043, Japan. RI Takakura, Hiroyuki/D-6146-2012; Inaba, Akira/G-8887-2011; Canfield, Paul/H-2698-2014 NR 19 TC 10 Z9 10 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 723 EP 726 DI 10.1016/S0921-5093(00)01322-8 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900168 ER PT J AU Heggen, M Feuerbacher, M Schall, P Klein, H Fisher, IR Canfield, PC Urban, K AF Heggen, M Feuerbacher, M Schall, P Klein, H Fisher, IR Canfield, PC Urban, K TI Plasticity of icosahedral Zn-Mg-Dy single quasicrystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystals; plastic deformation; dislocations ID PD-MN SINGLE; QUASI-CRYSTALS; DEFORMATION; GROWTH AB We present the results of first deformation experiments on Zn-Mg-Dy icosahedral single quasicrystals. The samples were produced by the flux growth technique. The plastic deformation experiments were performed at temperatures between 490 and 530 degreesC at strain rates of 10(-5) and 10(-6) s(-1). The thermodynamic activation parameters of the deformation process were determined. The stress-strain curves show strong yielding followed by a steady state regime with a constant flow stress level up to strains of about 8%. Microstructural investigations by transmission electron microscopy on deformed samples indicate a deformation mechanism mediated by dislocations. We found a high density of planar defects which were interpreted as slip planes of moving dislocations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Forschungszentrum Julich GmbH, Inst Festkorperforsch, D-52425 Julich, Germany. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Heggen, M (reprint author), Forschungszentrum Julich GmbH, Inst Festkorperforsch, D-52425 Julich, Germany. RI Feuerbacher, Michael/K-3768-2013; Heggen, Marc/K-5099-2013; Canfield, Paul/H-2698-2014 OI Feuerbacher, Michael/0000-0003-2882-4960; Heggen, Marc/0000-0002-2646-0078; NR 12 TC 9 Z9 9 U1 2 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 781 EP 785 DI 10.1016/S0921-5093(00)01073-X PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900180 ER PT J AU Belin-Ferre, E Dubois, JM Fournee, V Brunet, P Sordelet, DJ Zhang, LM AF Belin-Ferre, E Dubois, JM Fournee, V Brunet, P Sordelet, DJ Zhang, LM TI About the Al 3p density of states in Al-Cu-Fe compounds and its relation to the compound stability and apparent surface energy of quasicrystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystal; electronic structure; Hume-Rothery mechanism; stability; surface energy; wetting ID HUME-ROTHERY ALLOYS; QUASI-CRYSTALS; ELECTRONIC DISTRIBUTIONS AB We report the characteristic parameters of the Al 3p densities of stares gained from a thorough study of many Al-Cu(-Fe) intermetallics including quasicrystalline and approximant phases using X-ray emission spectroscopy. These parameters are the density of states at the Fermi energy E-F, the average binding energy due to Al 3p states and the second moment of their distribution. Hence, we demonstrate that the contribution to the compound stability arising from localization of Al 3p states via the Hume-Rothery mechanism is maximum for the icosahedral state. We also show that Al-transition metal sp-d hybridization is enhanced in the presence of icosahedral order. Finally, we confirm the already pointed out relationship between depth of the pseudo-gap at E-F and apparent surface energy of the samples. (C) 2000 Elsevier Science B.V. All rights reserved. C1 LCPMR, UMR 7614, F-75231 Paris, France. CINQ, GDR, F-75231 Paris, France. EMN, LSG2M UMR 7584, F-54042 Nancy, France. EMN, GDR CINQ, F-54042 Nancy, France. Ames Lab, Ames, IA 50011 USA. Dalian Univ Technol, Dept Mat Engn, Dalian 116023, Peoples R China. RP Belin-Ferre, E (reprint author), LCPMR, UMR 7614, 11 Rue Pierre & Marie Curie, F-75231 Paris, France. NR 19 TC 19 Z9 19 U1 2 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 818 EP 821 DI 10.1016/S0921-5093(00)01306-X PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900189 ER PT J AU Cappello, G Schmithusen, F Chevrier, J Comin, F Stierle, A Formoso, V de Boissieu, M Boudard, M Lograsso, TA Jenks, C Delaney, D AF Cappello, G Schmithusen, F Chevrier, J Comin, F Stierle, A Formoso, V de Boissieu, M Boudard, M Lograsso, TA Jenks, C Delaney, D TI Characterization of surface morphologies at the Al-Pd-Mn fivefold surface SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystal; surfaces; X-ray reflectivity; scanning probe microscopy ID AL70PD21MN9 QUASI-CRYSTAL; AL68PD23MN9; DIFFRACTION; LEED; STM AB Fivefold surfaces of Al-Pd-Mn quasicrystal have been prepared under ultra-high vacuum (UHV) by sputtering and annealing above 700 K and characterized by electron diffraction, Auger spectroscopy and X-ray photoemission spectroscopy (LEED, AES, XPS). X-ray reflectivity at grazing incidence reveals that an in situ temperature annealing at 900 K is necessary to irreversibly produce the signature of a Bat and bulk terminated surface. Air-AFM investigations of surfaces prepared below or in the vicinity of this transformation temperature show a large scale structure in the micrometer range with high steps and parallel terraces. Terrace morphology is dominated by clusters with a typical size of about 10 nm. Nanometer steps can coexist with this cluster structure. With UHV-STM, terrace roughness based on cluster assembly is found to extend down to the nanometer scale. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CNRS, LEPES, F-38042 Grenoble 9, France. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Inst Natl Polytech Grenoble, LTPCM, F-38402 St Martin Dheres, France. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Chevrier, J (reprint author), CNRS, LEPES, BP 166, F-38042 Grenoble 9, France. RI Chevrier, Joel/D-3280-2012; OI Chevrier, Joel/0000-0001-5609-6863 NR 14 TC 5 Z9 5 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 822 EP 825 DI 10.1016/S0921-5093(00)01330-7 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900190 ER PT J AU Wehner, BI Koster, U Rudiger, A Pieper, C Sordelet, DJ AF Wehner, BI Koster, U Rudiger, A Pieper, C Sordelet, DJ TI Oxidation of Al-Cu-Fe and Al-Pd-Mn quasicrystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE oxidation; quasicrystal; Al-Cu-Fe; Al-Pd-Mn ID SURFACE; SPECTRA AB Oxidation of Al-Cu-Fe and Al-Pd-Mn quasicrystals as compared to related crystalline phases was studied in air at high temperatures, Parabolic rate constants at 840 degreesC were about 6 x 10(-12) g(2) cm(-4) s(-1) for icosahedral Al-Cu-Fe, but only 3 x 10(-13) g(2) cm(-4) s(-1) for cubic AlFe. The oxide layer formed on the icosahedral alloy was inhomogeneous with respect to the oxide growth morphology. Oxide compositions were studied by Auger electron spectroscopy (AES) and X-ray induced photo electron spectroscopy (XPS). The theta -Al2O3 layer on Al-Cu-Fe did not contain any quantities of Cu or Fe that were significant according to the analyses by AES and XPS. In an advanced oxidation stage the theta -Al2O3 layer was penetrated by alpha -Al2O3 nodules, which contained about 5% CU. Oxidation of Al-Pd-Mn quasicrystals was found to be strongly influenced by evaporation of Mn. Whereas the formation of delta -Al2O3 was observed at 800 degreesC on Al-Pd-Mn quasicrystals followed by growth of needle-like theta -Al2O3, oxidation of hot isostatically pressed (HIPed) specimens at 850 degreesC led to the formation of a theta -Al2O3 layer containing also extremely thin areas. The metallic AI(LMM) Auger peak observed in these areas was four times the oxidic AI(LMM) peak. Neither in the thick nor the thin oxide areas were Pd or Mn observed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Univ Dortmund, Dept Chem Engn, D-44221 Dortmund, Germany. RP Wehner, BI (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 15 TC 14 Z9 14 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 830 EP 833 DI 10.1016/S0921-5093(00)01060-1 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900192 ER PT J AU Sordelet, DJ Widener, SD Tang, Y Besser, MF AF Sordelet, DJ Widener, SD Tang, Y Besser, MF TI Characterization of a commercially produced Al-Cu-Fe-Cr quasicrystalline coating SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE coatings; quasicrystals; icosahedral; decagonal ID QUASI-CRYSTALLINE; BEHAVIOR AB A commercially produced Al-Cu-Fe-Cr thermal spray cookware coating was characterized. Gas-atomized powders with a nominal composition of Al71Cu10Fe8.5Cr10.5 were apparently used to form the coatings. The coating is very uniform and contains a quasicrystalline icosahedral phase along with a second phase that is either a quasicrystalline decagonal phase or its nearly identical crystalline approximant. The phases show evidence of structural imperfection and appear to be in a highly transitional state, which is likely caused by the rapid cooling during thermal spraying. A large fraction of unmelted particles and microcracks were observed throughout the coating. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Met & Ceram Program, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Iowa State Univ, Dept Mech Engn, Ames, IA 50011 USA. RP Sordelet, DJ (reprint author), Iowa State Univ, Ames Lab, Met & Ceram Program, Ames, IA 50011 USA. NR 6 TC 31 Z9 35 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 834 EP 837 DI 10.1016/S0921-5093(00)01056-X PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900193 ER PT J AU Cappello, G Dechelette, A Schmithusen, F Decossas, S Chevrier, J Comin, F Formoso, V de Boissieu, M Jack, T Colella, R Lograsso, TA Jenks, C AF Cappello, G Dechelette, A Schmithusen, F Decossas, S Chevrier, J Comin, F Formoso, V de Boissieu, M Jack, T Colella, R Lograsso, TA Jenks, C TI Bulk and surface evidence for the long-range spatial modulation of X-ray absorption in the Al-Pd-Mn quasicrystal at Bragg incidence SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystal; X-ray diffraction; X-ray standing wave; surfaces ID STANDING WAVES; ALPDMN; DIFFRACTION; SYMMETRY AB An X-ray standing waves experiment was performed at the ID32 beam line of the ESRF on an Al-Pd-Mn quasicrystal with the X-ray beam at normal incidence. The X-ray photoemission core levels for each element were recorded to probe the surface. The drain current, i.e. the electron current from ground needed to neutralize the irradiated sample and to compensate the photoemitted electrons was also recorded as a bulk probe that integrates over all atoms of the sample. Within the two-beam approximation applied to quasicrystals, a simple analysis of this effect is proposed. This provides a direct-space illustration of the diffraction process in a quasiperiodic structure. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CNRS, LEPES, F-38042 Grenoble 9, France. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Inst Natl Polytech Grenoble, LTPCM, F-38402 St Martin Dheres, France. NIST, Gaithersburg, MD 20899 USA. Purdue Univ, W Lafayette, IN 47907 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Chevrier, J (reprint author), CNRS, LEPES, BP 166, F-38042 Grenoble 9, France. EM chevrier@esrf.fr RI Chevrier, Joel/D-3280-2012; OI Chevrier, Joel/0000-0001-5609-6863 NR 11 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 863 EP 866 DI 10.1016/S0921-5093(00)01080-7 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900200 ER PT J AU Ledieu, J Muryn, CA Thornton, G Cappello, G Chevrier, J Diehle, RD Lograsso, TA Delaney, D McGrath, R AF Ledieu, J Muryn, CA Thornton, G Cappello, G Chevrier, J Diehle, RD Lograsso, TA Delaney, D McGrath, R TI Decomposition of the five-fold surface of Al70Pd21Mn9 at elevated temperature SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT 7th International Conference on Quasicrystals (ICQ7) CY SEP 20-24, 1999 CL UNIV STUTTGART, STUTTGART, GERMANY SP German Sci Fdn, State Baden Wurttemberg, Minist Sci Res & Culture, Univ Tubingen, Max Planck Inst Met Res, Landesbank Baden Wurttemberg, Volksbank Trossingen HO UNIV STUTTGART DE quasicrystals; surface; Al70Pd21Mn9; STM; Al3Mn ID AL-PD-MN; QUASI-CRYSTALS; AL68PD23MN9; AL70PD20MN10; LEED; STM AB Several surface phases have previously been identified on the five-fold surface of the Al70Pd21Mn9 quasicrystal. Two of these, the clustered and terraced phases, have been discovered by scanning tunnelling microscopy (STM) studies. In this paper, we report STM images showing the existence of a new phase on this surface. This new topography was obtained by annealing the sample close to its melting point for several minutes. A model is presented which exhibits the main features of the structure. The unit-cell dimensions match those of the Al3Mn orthorhombic phase. Mechanical polishing followed by sputtering and annealing restored a pentagonal quasicrystalline surface indicating that the decomposition is a near-surface phenomenon. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Liverpool, Surface Sci Res Ctr, Liverpool L69 3BX, Merseyside, England. Univ Liverpool, Dept Phys, Liverpool L69 3BX, Merseyside, England. Univ Manchester, Surface Sci Res Ctr, Manchester M13 9PL, Lancs, England. Univ Manchester, Dept Chem, Manchester M13 9PL, Lancs, England. CNRS, LEPES, F-38042 Grenoble 9, France. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP McGrath, R (reprint author), Univ Liverpool, Surface Sci Res Ctr, POB 147, Liverpool L69 3BX, Merseyside, England. RI McGrath, Ronan/A-1568-2009; Chevrier, Joel/D-3280-2012; Ledieu, Julian/F-1430-2010; OI McGrath, Ronan/0000-0002-9880-5741; Chevrier, Joel/0000-0001-5609-6863 NR 22 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD DEC 15 PY 2000 VL 294 SI SI BP 871 EP 873 DI 10.1016/S0921-5093(00)01040-6 PG 3 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 388HW UT WOS:000166175900202 ER PT J AU Oldehoeft, R AF Oldehoeft, R TI Taming complexity in high-performance computing SO MATHEMATICS AND COMPUTERS IN SIMULATION LA English DT Article; Proceedings Paper CT International Symposium on Computational Sciences to honor John R Rice CY MAY 22-26, 1999 CL W LAFAYETTE, INDIANA SP Purdue Univ, Dept Comp Sci, Int Federat Informat Processing, Working Grp 2 5, Int Assoc Math & Comp Simulat DE high-performance computing; object-orientated frameworks; run-time systems; scientific visualization; software component architecture; Linux clusters AB Today's high-performance computing environments, and the applications that must exploit them, have become much more complex than ever. We now build ensembles of large, shared-memory parallel computers, linked together with high-speed networks, in an attempt to achieve previously unheard-of speeds and still retain a 'general-purpose' capability for running diverse applications. Demands for greater precision and realism in today's computer simulations of physical phenomena tax the imagination of the most aggressive system designers. Enhancing the accuracy of tomorrow's simulations requires simultaneously accounting for more physical, chemical and biological components. Predictive simulation is essential for making informed, science-based decisions on questions of; national importance, including stockpile stewardship, global climate change, wild-fires, earthquakes and epidemics. These applications are too massive and inter-related to be built, verified, tuned and maintained by conventional methods. Software teams in the Advanced Computing Laboratory (ACL) at Los Alamos National Laboratory, along with collaborators world-wide, are building an integrated software infrastructure for scientific simulation development. This paper describes the ACL projects now underway in object-oriented frameworks, scalable run-time software, scientific visualization, software component architecture, and high-end and experimental computer systems. We include achieved results and the status of projects. Published by Elsevier Science B.V. on behalf of IMACS. C1 Univ Calif Los Alamos Natl Lab, Adv Comp Lab, Los Alamos, NM 87545 USA. RP Oldehoeft, R (reprint author), Univ Calif Los Alamos Natl Lab, Adv Comp Lab, MS B287, Los Alamos, NM 87545 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4754 J9 MATH COMPUT SIMULAT JI Math. Comput. Simul. PD DEC 15 PY 2000 VL 54 IS 4-5 BP 341 EP 357 DI 10.1016/S0378-4754(00)00193-2 PG 17 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 386FT UT WOS:000166050700011 ER PT J AU Nesvizhskii, AI Ankudinov, AL Rehr, JJ Baberschke, K AF Nesvizhskii, AI Ankudinov, AL Rehr, JJ Baberschke, K TI Interpretation of x-ray magnetic circular dichroism and x-ray absorption near-edge structure in Ni SO PHYSICAL REVIEW B LA English DT Article ID RESONANT-PHOTOEMISSION; 3D ELEMENTS; SUM-RULES; NICKEL; SPIN; SPECTROSCOPY; METALS; FILMS AB An interpretation of the spectral features in the Ni L-3 x-ray absorption near-edge structure and x-ray magnetic circular dichroism signals is presented, based on both one-electron multiple-scattering and atomic-multiplet calculations. Neither of these approaches is fully satisfactory. Although most of the observed features are reproduced by one-electron calculations, the pronounced peak about 3 eV above the edge is not. Conversely, the peal; at 6 eV and the smooth plateau just beyond are not reproduced by the multiplet calculations. The lack of the 3-eV feature is attributed to the neglect of many-body effects in the interaction between core hole and final-state d" configuration. The observed negative plateau between L-3 and L-2 edges is attributed to transitions to spin-polarized continuum epsilond states, and the 6-eV peak, to multiple scattering paths of intermediate range and disappears fur Ni clusters smaller than 13 atoms. The necessity of both,one-electron and atomic-multiplet calculations to explain all features in the data demonstrates the need for a combined approach. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Stanford Univ, Stanford Linear Accelerator Ctr, SSRL, Stanford, CA 94309 USA. RP Nesvizhskii, AI (reprint author), Univ Washington, Dept Phys, Seattle, WA 98195 USA. RI Nesvizhskii, Alexey/A-5410-2012 OI Nesvizhskii, Alexey/0000-0002-2806-7819 NR 26 TC 25 Z9 25 U1 0 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 23 BP 15295 EP 15298 DI 10.1103/PhysRevB.62.15295 PG 4 WC Physics, Condensed Matter SC Physics GA 385GK UT WOS:000165995100006 ER PT J AU El-Kady, I Sigalas, MM Biswas, R Ho, KM Soukoulis, CM AF El-Kady, I Sigalas, MM Biswas, R Ho, KM Soukoulis, CM TI Metallic photonic crystals at optical wavelengths SO PHYSICAL REVIEW B LA English DT Article ID STOP BANDS AB We theoretically study three-dimensional metallic photonic-band-gap (PBG) materials at near-infrared and optical wavelengths. Our main objective is to find the importance of absorption in the metal and the suitability of observing photonic band gaps in this structure. For that reason, we study simple cubic structures and the metallic scatterers are either cubes or interconnected metallic rods. Several different metals have been studied (aluminum, gold, copper, and silver). Copper gives the smallest absorption and aluminum is more absorptive. The isolated metallic cubes are less lossy than the connected rod structures. The calculations suggest that isolated copper scatterers are very attractive candidates for the fabrication of photonic crystals at the optical wavelengths. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP El-Kady, I (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI El-Kady, Ihab/D-2886-2013; Soukoulis, Costas/A-5295-2008 OI El-Kady, Ihab/0000-0001-7417-9814; NR 21 TC 141 Z9 143 U1 2 U2 25 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 23 BP 15299 EP 15302 DI 10.1103/PhysRevB.62.15299 PG 4 WC Physics, Condensed Matter SC Physics GA 385GK UT WOS:000165995100007 ER PT J AU Bellaiche, L Modine, NA Jones, ED AF Bellaiche, L Modine, NA Jones, ED TI Unusual evolution of the lowest unoccupied state in Ga(As0.5-yP0.5-yN2y) SO PHYSICAL REVIEW B LA English DT Article ID OPTICAL-PROPERTIES; GAP1-XNX ALLOYS; BAND-GAPS; GAASN; TRANSITIONS; SEMICONDUCTORS; LOCALIZATION; GAAS1-XPX; SPECTRA; PHONON AB The character of the lowest unoccupied state in the random Ga(As0.5-yP0.5-yN2y) alloys is investigated for small nitrogen concentrations (0.1%<2y<1.0%) using a pseudopotential technique. As nitrogen is added to Ga(As0.5P0.5), this state evolves from an impurity localized level to a delocalized bandlike state. This evolution involves two processes. The first process is an anticrossing between the deep-gap nitrogen impurity level existing in the dilute alloy limit y-->0 and the Gamma (1c)-like extended state of Ga(As0.5P0.5). The second process is the formation of an impurity subband due to the interaction of the deep-gap nitrogen levels. These two processes are expected to occur in any Ga(As1-x-y1 Px-y2Ny1 + y2) alloys for which x is larger than 0.3. C1 Univ Arkansas, Dept Phys, Fayetteville, AR 72701 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Bellaiche, L (reprint author), Univ Arkansas, Dept Phys, Fayetteville, AR 72701 USA. NR 27 TC 8 Z9 8 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 23 BP 15311 EP 15314 DI 10.1103/PhysRevB.62.15311 PG 4 WC Physics, Condensed Matter SC Physics GA 385GK UT WOS:000165995100010 ER PT J AU Baskes, MI AF Baskes, MI TI Atomistic model of plutonium SO PHYSICAL REVIEW B LA English DT Article ID EMBEDDED-ATOM METHOD; METALS; POTENTIALS; SILICON; EQUILIBRIUM; IMPURITIES; DYNAMICS AB A modified embedded atom model of Pu has been developed. This simple atomic level model is able to reproduce the extreme anomalous behavior of this complex element. The calculated energetics and volume of the seven stable phases of Pu are found to be in close agreement with experiment. Calculated thermodynamic and elastic properties are also in reasonable agreement with the available experimental data. The model also reproduces the unusual properties of the liquid phase, low melting point, and contraction upon melting. It is demonstrated that the anomalous properties of plutonium arise from the rapid spatial variation of the f-electron density. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Baskes, MI (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 26 TC 76 Z9 78 U1 3 U2 16 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 DEC 15 PY 2000 VL 62 IS 23 BP 15532 EP 15537 DI 10.1103/PhysRevB.62.15532 PG 6 WC Physics, Condensed Matter SC Physics GA 385GK UT WOS:000165995100055 ER PT J AU Kakar, S Nelson, AJ Treusch, R Heske, C van Buuren, T Jimenez, I Pagoria, P Terminello, LJ AF Kakar, S Nelson, AJ Treusch, R Heske, C van Buuren, T Jimenez, I Pagoria, P Terminello, LJ TI Electronic structure of the energetic material 1,3,5-triamino-2,4,6-trinitrobenzene SO PHYSICAL REVIEW B LA English DT Article ID LOSS SPECTRA; SHELL; MOLECULES; CO AB Synchrotron radiation is used to study the electronic structure of the energetic material 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). Element and site-specific density of unoccupied electronic states in TATE is probed by x-ray-absorption spectroscopy at the C, N, and O K edges. In addition to illuminating the electronic structure of TATE, the absorption data enable the understanding of microscopic changes occurring in such compounds due to various damage mechanisms. The absorption data are further supplemented by data from the core-level and valence-band photoelectron spectroscopy of thin films of TATE. C1 Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. RP Nelson, AJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. RI Jimenez, Ignacio/F-7422-2010; Treusch, Rolf/C-3935-2015; OI Jimenez, Ignacio/0000-0001-5605-3185; Treusch, Rolf/0000-0001-8479-8862 NR 27 TC 27 Z9 29 U1 2 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 23 BP 15666 EP 15672 DI 10.1103/PhysRevB.62.15666 PG 7 WC Physics, Condensed Matter SC Physics GA 385GK UT WOS:000165995100071 ER PT J AU Karis, O Magnuson, M Wiell, T Weinelt, M Wassdahl, N Nilsson, A Martensson, N Holmstrom, E Niklasson, AMN Eriksson, O AF Karis, O Magnuson, M Wiell, T Weinelt, M Wassdahl, N Nilsson, A Martensson, N Holmstrom, E Niklasson, AMN Eriksson, O TI Observation of short- and long-range hybridization of a buried Cu monolayer in Ni SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC CIRCULAR-DICHROISM; X-RAY-ABSORPTION; FERROMAGNETIC NICKEL; CO/CU MULTILAYERS; SPECTROSCOPY; INTERFACES; SURFACES; EDGES; CO AB The electronic structure of a Cu monolayer buried in Ni fcc(100) is studied by means of x-ray emission and absorption spectroscopies in combination with first principles calculations. The local character of the x-ray probes allows us to investigate changes in the chemical interaction for these ultrathin film systems. In comparison to bulk Cu, the occupied d states of a buried Cu monolayer, as-mapped in the x-ray emission spectrum, remain mostly unaltered. The absorption spectrum on the other hand shows that the empty states of the buried Cu monolayer are modified, and instead resemble the unoccupied electronic density of bulk Ni. These findings agree well with our first principle electronic structure calculations and the results are interpreted in terms of short- and long-range hybridization. C1 Uppsala Univ, Dept Phys, S-75121 Uppsala, Sweden. Univ Paris 06, Chim Phys Lab, F-75231 Paris, France. Uppsala Univ, Condensed Matter Theory Grp, S-75121 Uppsala, Sweden. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87544 USA. RP Karis, O (reprint author), Uppsala Univ, Dept Phys, Box 530, S-75121 Uppsala, Sweden. RI Holmstrom, Erik/A-5308-2009; Nilsson, Anders/E-1943-2011; Magnuson, Martin/F-5145-2012; Eriksson, Olle/E-3265-2014 OI Holmstrom, Erik/0000-0002-1198-3861; Nilsson, Anders/0000-0003-1968-8696; Magnuson, Martin/0000-0002-0317-0190; Eriksson, Olle/0000-0001-5111-1374 NR 22 TC 5 Z9 5 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 DEC 15 PY 2000 VL 62 IS 24 BP 16239 EP 16242 PG 4 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800007 ER PT J AU Greanya, VA Tonjes, WC Liu, R Olson, CG Chung, DY Kanatzidis, MG AF Greanya, VA Tonjes, WC Liu, R Olson, CG Chung, DY Kanatzidis, MG TI Electronic structure of Bi2Te3 studied by angle-resolved photoemission SO PHYSICAL REVIEW B LA English DT Article ID VALENCE-BAND AB We report a detailed study of the electronic structure of Bi2Te3, to our knowledge the best room temperature thermoelectric material known to date, using angle-resolved photoemission. Dispersions of the valence bands were determined. A sixfold k-space degeneracy in the valence-band maximum is found. The quasi-two-dimensional nature of the electronic structure was demonstrated by the weakly dispersive bands along the Gamma -Z direction. Experimental results are compared with theoretical band-structure calculations and with de Haas-van Alphen and Shubnikov-de Haas experiments. C1 Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames, IA 50011 USA. Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA. RP Greanya, VA (reprint author), Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. NR 22 TC 15 Z9 16 U1 0 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 16425 EP 16429 DI 10.1103/PhysRevB.62.16425 PG 5 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800046 ER PT J AU Moore, DP Joyce, JJ Arko, AJ Sarrao, JL Morales, L Hochst, H Chuang, YD AF Moore, DP Joyce, JJ Arko, AJ Sarrao, JL Morales, L Hochst, H Chuang, YD TI Bulk electronic structure of YbInCu4 from photoemission: A unique test of the single impurity model SO PHYSICAL REVIEW B LA English DT Article ID VALENCE PHASE-TRANSITION; LOW-ENERGY EXCITATIONS; HEAVY-FERMION SYSTEMS; PHOTOELECTRON-SPECTROSCOPY; KONDO RESONANCE; SPECTRA; CE; YBXIN1-XCU2; DEPENDENCE; BEHAVIOR AB The heavy fermion compound YbInCu4 presents a unique opportunity to test the single impurity model (SIM) owing to its isostructural phase transition at 42 K, whereby the Kondo temperature suddenly increases from 30 K above, to 400 K below the transition. Photoelectron spectroscopy (PES) at varying temperatures is well suited for this test, Previous researchers have claimed that PES probes only a subsurface region which differs from the bulk, thus rendering PES less than optimum for such a test. We present PES data in which a single-crystal sample was cooled through the phase transition only once in order to minimize defect formation. We find clear evidence of the bulk transition and no evidence for a subsurface region. The PES spectra do not agree with the predictions of the SIM and its approximate solution, the noncrossing approximation. We propose that only a periodic model is applicable to highly correlated, stoichiometric heavy fermion systems. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Ctr Synchrotron Radiat, Stoughton, WI 53706 USA. Univ Colorado, Boulder, CO 80302 USA. RP Moore, DP (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 32 TC 26 Z9 26 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 16492 EP 16499 DI 10.1103/PhysRevB.62.16492 PG 8 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800053 ER PT J AU Reed, EJ Joannopoulos, JD Fried, LE AF Reed, EJ Joannopoulos, JD Fried, LE TI Electronic excitations in shocked nitromethane SO PHYSICAL REVIEW B LA English DT Article ID SOLID NITROMETHANE; ENERGETIC MATERIALS; BAND-GAPS; SEMICONDUCTORS; PSEUDOPOTENTIALS; TRANSITIONS; SENSITIVITY; EXPLOSIVES; INSULATORS; CRYSTALS AB The nature of electronic excitations in crystalline solid nitromethane under conditions of shock loading and static compression are examined. Density-functional theory calculations are used to determine the crystal bandgap under hydrostatic stress, uniaxial strain, and shear strain. Bandgap lowering under uniaxial strain due to molecular defects and vacancies is considered. Ab initio molecular-dynamics simulations are done of all possible nearest-neighbor collisions at a shock front, and of crystal shearing along a sterically hindered slip plane. In all cases, the bandgap is not lowered enough to produce a significant population of excited states in the crystal. The nearly free rotation of the nitromethane methyl group and localized nature of the highest occupied molecular orbital and lowest unoccupied molecular orbital states play a role in this result. Dynamical effects have a more significant effect on the bandgap than static effects, but relative molecule velocities in excess of 6 km/s are required to produce a significant thermal population of excited states. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. RP Reed, EJ (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. EM evan@mit.edu RI Fried, Laurence/L-8714-2014 OI Fried, Laurence/0000-0002-9437-7700 NR 36 TC 74 Z9 78 U1 3 U2 13 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 16500 EP 16509 DI 10.1103/PhysRevB.62.16500 PG 10 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800054 ER PT J AU Tchernyshyov, O AF Tchernyshyov, O TI Parity and time-reversal anomaly in a semiconductor SO PHYSICAL REVIEW B LA English DT Article ID REALIZATION AB The physics of a parity anomaly, potentially observable in a narrow-gap semiconductor, is revisited. Fradkin, Dagotto, and Boyanovsky have suggested [Phys. Rev. Lett. 57, 2967 (1986)] that a Hall current of anomalous parity can be induced by a Peierls distortion on a domain wall. I argue that a perturbation inducing the parity anomaly must break the time-reversal symmetry, which rules out the Peierls distortion as a potential cause. I list all possible perturbations that can generate the anomaly. C1 Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Tchernyshyov, O (reprint author), Inst Adv Study, Sch Nat Sci, Olden Lane, Princeton, NJ 08540 USA. EM oleg@ias.edu NR 16 TC 3 Z9 3 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 16751 EP 16755 DI 10.1103/PhysRevB.62.16751 PG 5 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800089 ER PT J AU Munteanu, FM Rickel, DG Perry, CH Kim, Y Simmons, JA Reno, JL AF Munteanu, FM Rickel, DG Perry, CH Kim, Y Simmons, JA Reno, JL TI Bright and dark triplet states of the negatively charged magnetoexcitons revealed in photoluminescence and time-resolved measurements SO PHYSICAL REVIEW B LA English DT Article ID GAAS QUANTUM-WELLS; HIGH MAGNETIC-FIELDS; EXCESS ELECTRONS; EXCITONS; SPECTROSCOPY AB Continuous and time-resolved magnetophotoluminescence measurements of three GaAs/AlxGa1-xAs heterostructures have been made in high magnetic fields. The spectra revealed the presence of a singlet and two tripler states (the so-called "bright" and ''dark'' states) of the negatively charged magnetoexciton, in addition to the neutral exciton. For an asymmetrically doped single quantum well sample, the singlet and the dark triplet states converge (and possibly cross) at a field of about 40 T. The two single heterojunction samples on the other hand show no such convergence, and the singlet remains the fundamental state at least in fields to 60 T. The lifetimes of the charged magnetoexcitons increased linearly with held, whereas the neutral exciton was essentially field independent. The results clarify earlier experimental studies, and provide a confirmation of a recent theory of the behavior of charged magnetoexcitons in magnetic fields by Wojs et al. C1 Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Dongguk Univ, Quantum Funct Semicond Res Ctr, Seoul, South Korea. Northeastern Univ, Dept Phys, Boston, MA 02115 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Veeco Instruments, Longmont, CO 80501 USA. RP Munteanu, FM (reprint author), Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, POB 1663, Los Alamos, NM 87545 USA. NR 24 TC 9 Z9 9 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 16835 EP 16839 DI 10.1103/PhysRevB.62.16835 PG 5 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800103 ER PT J AU Ismail Hofmann, P Plummer, EW Bungaro, C Kress, W AF Ismail Hofmann, P Plummer, EW Bungaro, C Kress, W TI Surface lattice dynamics of Mg(0001) SO PHYSICAL REVIEW B LA English DT Article ID INELASTIC ELECTRON-SCATTERING; ADSORBATE VIBRATIONS; PHONON-DISPERSION; PSEUDOPOTENTIALS; ALUMINUM; ANHARMONICITY; RELAXATION; BERYLLIUM; ABINITIO; BE(0001) AB A study of the surface lattice dynamics of s-p bonded Mg(0001) using momentum-resolved inelastic electron scattering and nb initio calculations is reported. Three phonon modes at (K) over bar and four phonon modes at (M) over bar were observed, all in excellent agreement with calculations. In an attempt to understand the origin of changes in the surface force constants compared to the bulk force constants, the theoretical dispersion of the Rayleigh mode using bulk truncated and real surface force constants was compared for the hexagonal surface of three s-p bonded metals, Al, Mg, and Be. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Aarhus Univ, Inst Storage Ring Facil, DK-8000 Aarhus C, Denmark. SISSA, I-34014 Trieste, Italy. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. RP Ismail (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 42 TC 3 Z9 3 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 17012 EP 17019 DI 10.1103/PhysRevB.62.17012 PG 8 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800123 ER PT J AU Feibelman, PJ AF Feibelman, PJ TI Ab initio step and kink formation energies on Pb(111) SO PHYSICAL REVIEW B LA English DT Article ID ABINITIO MOLECULAR-DYNAMICS; WAVE BASIS-SET; ULTRASOFT PSEUDOPOTENTIALS; VICINAL SURFACES; ELECTRON SYSTEMS; METALS; FLUCTUATIONS; TRANSITION; CU(111); SHAPE AB Ab initio formation energies for (100)- and (Ill)-microfacet steps on Pb(lll) are in satisfactory agreement with measured values, given that these values are known only as well as the Pb(lll) surface energy; the calculated step energy ratio, 1.22, is within similar to3% of experiment. In contrast, calculated kink formation energies, 41 and 60 meV for the two step types, are 40-50 % below published experimental values derived from scanning tunneling microscope images. The discrepancy results from interpreting the images with a step-stiffness versus kink energy relation appropriate to (100) but not (111) surfaces. Good agreement is found when the step-stiffness data are reinterpreted, taking proper account of the trigonal symmetry of Pb(111). C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 35 TC 32 Z9 32 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP 17020 EP 17025 DI 10.1103/PhysRevB.62.17020 PG 6 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800124 ER PT J AU Franceschetti, A Zunger, A AF Franceschetti, A Zunger, A TI Optical transitions in charged CdSe quantum dots SO PHYSICAL REVIEW B LA English DT Article ID PHOTOLUMINESCENCE; SPECTROSCOPY; NANOCRYSTALS; EXCITONS; COULOMB AB Using a many-body approach based on single-particle pseudopotential wave functions, we calculate the dependence of the optical transitions in CdSe nanocrystals on the presence of "spectator" electrons or holes. We find that (i) as a result of the different localization of the electron and hole wave functions, the absorption lines shift by as much as 22 meV/unit charge when electrons or holes are loaded into the quantum dot. (ii) The lowest emission line is significantly red shifted with respect to the lowest allowed absorption line. (iii) Trapping of;a "spectator" hole in a surface state is predicted to lead to dramatic changes in the absorption spectrum, including the appearance of new transitions. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Franceschetti, A (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Zunger, Alex/A-6733-2013 NR 18 TC 55 Z9 55 U1 1 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP R16287 EP R16290 DI 10.1103/PhysRevB.62.R16287 PG 4 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800019 ER PT J AU Hebenstreit, W Ruzycki, N Herman, GS Gao, Y Diebold, U AF Hebenstreit, W Ruzycki, N Herman, GS Gao, Y Diebold, U TI Scanning tunneling microscopy investigation of the TiO2 anatase (101) surface SO PHYSICAL REVIEW B LA English DT Article ID TIO2(110); WATER AB We report the first scanning tunneling microscopy (STM) study of single-crystalline anatase. Atomically resolved images of the (101) surface are consistent with a bulk-truncated (1x1) termination. Step edges run predominantly in the [010], [(1) over bar 11], and [(1) over bar(1) over bar1] directions. The surface is stable with very few point defects. Fourfold-coordinated Ti atoms at step edges are preferred adsorption sites and allow the identification of tunneling sites in STM. C1 Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Diebold, U (reprint author), Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. EM diebold@tulane.edu RI Diebold, Ulrike/A-3681-2010 OI Diebold, Ulrike/0000-0003-0319-5256 NR 17 TC 21 Z9 21 U1 4 U2 69 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 DEC 15 PY 2000 VL 62 IS 24 BP R16334 EP R16336 PG 3 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800031 ER PT J AU Mitsui, T Takayanagi, K AF Mitsui, T Takayanagi, K TI Extrinsic structure changes by STM at 65 K on Si(001) SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; LOW-TEMPERATURE; SURFACE; DISORDER AB Using variable-temperature scanning tunneling microscopy to image buckled dimers in a C(4 x 2) phase on Si(001) at 65 K under conventional scanning conditions, we have observed symmetric dimers in the P(2 x 1) phase and the flip-flop motion of dimers at the boundary of two different phases. Careful investigation shows that higher tunneling currents produce larger areas of P(2 x 1) phase and higher flip-flop rates of individual dimers. We have measured and plotted the flip-flop rate as a function of current. The origin of the phase transition and the flip-flop dimer motion are discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Japan Sci & Technol Corp, ERATO, Takayanagi Particle Surface Project, Akishima, Tokyo 196, Japan. Tokyo Inst Technol, Dept Mat Sci & Engn, Midori Ku, Yokohama, Kanagawa 227, Japan. RP Mitsui, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 15 TC 19 Z9 19 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 DEC 15 PY 2000 VL 62 IS 24 BP R16251 EP R16254 DI 10.1103/PhysRevB.62.R16251 PG 4 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800010 ER PT J AU Reizer, MY Vinokur, VM AF Reizer, MY Vinokur, VM TI Attenuation of two-dimensional plasmons SO PHYSICAL REVIEW B LA English DT Article ID MODES AB We calculate the attenuation of gapless plasmons in single- and double-layer electron systems by including higher-order corrections to the electron polarization operator from the Coulomb interaction. Both particle-hole excitations and plasmons in the intermediate states contribute to the relaxation. The obtained results are in good agreement with experimental findings for temperatures above 30 K. We also make predictions for plasmon attenuation at low temperatures where no experimental data are currently available. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Reizer, MY (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP R16306 EP R16309 DI 10.1103/PhysRevB.62.R16306 PG 4 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800024 ER PT J AU Shapiro, NA Kim, Y Feick, H Weber, ER Perlin, P Yang, JW Akasaki, I Amano, H AF Shapiro, NA Kim, Y Feick, H Weber, ER Perlin, P Yang, JW Akasaki, I Amano, H TI Dependence of the luminescence energy in InGaN quantum-well structures on applied biaxial strain SO PHYSICAL REVIEW B LA English DT Article ID GALLIUM NITRIDE; GAN; POLARIZATION; CONSTANTS AB Direct application of biaxial strain to GaN and InGaN/GaN multiple quantum-well (MQW) structures is achieved through the use of a specially designed pressure cell. The photoluminescence of the samples is measured as a function of the applied biaxial strain. The luminescence of the GaN sample redshifts with tensile strain in a manner that agrees quantitatively with the expected shrinkage of the energy gap. The luminescence of the InGaN MQW structures shows a smaller than expected redshift for one sample, and a blueshift for another. This blueshift agrees with calculations based on the built-in electric field and the piezoelectric effect in a quantum well in which the radiative recombination is dominated by the quantum-confined Stark effect. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. High Pressure Res Ctr Unipress, PL-01142 Warsaw, Poland. APA Opt, Blaine, MN 55449 USA. Meijo Univ, High Tech Res Ctr, Tempaku Ku, Nagoya, Aichi, Japan. Meijo Univ, Dept Mat Sci Engn, Tempaku Ku, Nagoya, Aichi, Japan. RP Shapiro, NA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 15 TC 2 Z9 2 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD DEC 15 PY 2000 VL 62 IS 24 BP R16318 EP R16321 DI 10.1103/PhysRevB.62.R16318 PG 4 WC Physics, Condensed Matter SC Physics GA 390QL UT WOS:000166307800027 ER PT J AU Anderson, PR Eaker, W Habib, S Molina-Paris, C Mottola, E AF Anderson, PR Eaker, W Habib, S Molina-Paris, C Mottola, E TI Attractor states and infrared scaling in de Sitter space SO PHYSICAL REVIEW D LA English DT Article ID ENERGY-MOMENTUM TENSOR; QUANTUM-FIELD-THEORY; ADIABATIC REGULARIZATION; PARTICLE HORIZONS; EARLY UNIVERSE; COSMOLOGICAL MODELS; PHYSICAL STATES; DESITTER SPACE; VACUUM STATES; SCALAR FIELDS AB The renormalized expectation value of the energy-momentum tensor for a scalar field with any mass m and curvature coupling xi is studied for an arbitrary homogeneous and isotropic physical initial state in de Sitter spacetime. We prove quite generally that (T-ab) has a fixed point attractor behavior at late times, which depends only on m and xi, for any fourth order adiabatic state that is infrared finite. Specifically, when m(2)+xiR>0, (T-ab) approaches the Bunch-Davies de Sitter invariant value at late times, independently of the initial state. When m = xi = 0, it approaches instead the de Sitter invariant Allen-Folacci value. When m = 0 and xi greater than or equal to0 we show that the state independent asymptotic value of the energy-momentum tensor is proportional to the conserved geometrical tensor H-(3)(ab), which is related to the behavior of the quantum effective action of the scalar field under global Weyl rescaling. This relationship serves to generalize the definition of the trace anomaly in the infrared for massless, nonconformal fields. In the case m(2) + xiR = 0, but m and xi separately different from zero, (T-ab) grows linearly with cosmic time at late times. For most values of m(2) and xi in the tachyonic cases, m(2) + xiR<0, (T-ab) grows exponentially at late cosmic times for all physically admissible initial states. C1 Wake Forest Univ, Dept Phys, Winston Salem, NC 27109 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. INTA, CSIC, Ctr Astrobiol, E-28850 Madrid, Spain. RP Anderson, PR (reprint author), Wake Forest Univ, Dept Phys, Winston Salem, NC 27109 USA. EM anderson@wfu.edu; eaker@alumni.wfu.edu; habib@lanl.gov; carmen@t6-serv.lanl.gov; emil@lanl.gov NR 51 TC 42 Z9 42 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 15 PY 2000 VL 62 IS 12 AR 124019 DI 10.1103/PhysRevD.62.124019 PG 24 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 386BH UT WOS:000166039900047 ER PT J AU Kachru, S Katz, S Lawrence, A McGreevy, J AF Kachru, S Katz, S Lawrence, A McGreevy, J TI Mirror symmetry for open strings SO PHYSICAL REVIEW D LA English DT Article ID F-THEORY; BRANES; GEOMETRY; DUALITY; SPACE AB We discuss the generation of superpotentials in d=4, N=1 supersymmetric field theories arising from type-IIA D6-branes wrapped on supersymmetric three-cycles of a Calabi-Yau threefold. In general, nontrivial superpotentials arise from sums over disc instantons. We then find several examples of special Lagrangian three-cycles with nontrivial topology which are mirror to obstructed rational curves, conclusively demonstrating the existence of such instanton effects. In addition, we present explicit examples of disc instantons ending on the relevant three-cycles. Finally, we give a preliminary construction of a mirror map for the open string moduli, in a large-radius limit of the type IIA compactification. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Linear Accelerator Ctr, Theory Grp, Stanford, CA 94309 USA. Oklahoma State Univ, Dept Math, Stillwater, OK 74078 USA. RP Kachru, S (reprint author), Stanford Univ, Dept Phys, Stanford, CA 94305 USA. OI Lawrence, Albion/0000-0003-4116-045X NR 37 TC 65 Z9 65 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD DEC 15 PY 2000 VL 62 IS 12 AR 126005 DI 10.1103/PhysRevD.62.126005 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 386BH UT WOS:000166039900079 ER PT J AU Mihaila, B Athan, T Cooper, F Dawson, J Habib, S AF Mihaila, B Athan, T Cooper, F Dawson, J Habib, S TI Exact and approximate dynamics of the quantum mechanical O(N) model SO PHYSICAL REVIEW D LA English DT Article ID LARGE-N EXPANSION; TIME EVOLUTION; SCALAR FIELD; UNIVERSE; CHAOS AB We study the dynamics of the quantum mechanical O(N) model as a specific example to investigate the systematics of a 1/N expansion. The closed time path formalism melded with an expansion in 1/N is used to derive time evolution equations valid to order 1/N (next-to-leading order). The effective potential is also obtained to this order and its properties are elucidated. In order to compare theoretical predictions against numerical solutions of the time-dependent Schrodinger equation, we consider two initial conditions consistent with O(N) symmetry, one of them a quantum roll, the other a wave packet initially to one side of the potential minimum, whose center has all coordinates equal. For the case of the quantum roll we map out the domain of validity of the large-N expansion. We also discuss the existence of unitarity violation in this expansion, a well-known problem faced by moment truncation techniques. The 1/N results, both static and dynamic, are contrasted with those given by a Hartree variational ansatz at given values of N. A comparison against numerical results leads us to conclude that late-time dynamical behavior, where nonlinear effects are significant, is not well described by either approximation. C1 Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Oak Ridge Natl Lab, Theoret Nucl Phys Div, Oak Ridge, TN USA. Coastal Carolina Univ, Dept Chem & Phys, Conway, SC 29526 USA. Univ Calif Los Alamos Natl Lab, EES Div, Los Alamos, NM 87545 USA. Boston Coll, Dept Phys, Chestnut Hill, MA 02167 USA. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. RP Mihaila, B (reprint author), Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. EM bogdan.mihaila@unh.edu; athan@lanl.gov; fcooper@lanl.gov; john.dawson@unh.edu; habib@lanl.gov RI Athan, Tara/C-8633-2009; Mihaila, Bogdan/D-8795-2013 OI Mihaila, Bogdan/0000-0002-1489-8814 NR 38 TC 30 Z9 30 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 DEC 15 PY 2000 VL 62 IS 12 AR 125015 DI 10.1103/PhysRevD.62.125015 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 386BH UT WOS:000166039900066 ER PT J AU Zechmann, CA Boyle, TJ Rodriguez, MA Kemp, RA AF Zechmann, CA Boyle, TJ Rodriguez, MA Kemp, RA TI Solvent influences on the molecular aggregation of magnesium aryloxides: synthesis, crystal structure, and solution characterization of Mg(OAr)(2)(L)(3) (OAr = DMP, DIP, TCP) and [Mg(DIP)(2)](3) SO POLYHEDRON LA English DT Article DE magnesium; aryloxide; structure; adduct AB Magnesium aryloxides were prepared in a variety of solvents through the reaction of dibutyl magnesium with sterically varied aryl alcohols: 2,6-dimethylphenol (H-DMP), 2,6-diisopropylphenol (H-DIP), and 2,4,6-trichlorophenol (H-TCP). Upon using a sufficiently strong Lewis-basic solvent, the solvated monomeric species Mg(DMP)(2)(py)(3) (1, py = pyridine), Mg(DIP)(2)(THF)(3), (2a, THF = tetrahydrofuran) Mg(TCP)(2)(THF)(3) (3) were isolated. Each of these complexes possesses a five-coordinate magnesium that adopts a trigonal bipyramidal geometry. In the absence of a Lewis base, the reaction with H-DIP yields a soluble trinuclear complex, [Mg(DIP)(2)](3) (2b). The Mg metal centers in 2b adopt a linear arrangement with a four-coordinate central metal while the outer metal centers are reduced to just three-coordinate. Solution spectroscopic methods suggest that while 2b remains intact, the monomeric species (1, 2a, and 3) are involved in equilibria which facilitate intermolecular ligand transfer. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. Union Carbide Corp, Westhollow Res Ctr, Houston, TX 77082 USA. RP Boyle, TJ (reprint author), Sandia Natl Labs, Adv Mat Lab, 1001 Univ Blvd SE, Albuquerque, NM 87106 USA. NR 20 TC 20 Z9 20 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0277-5387 J9 POLYHEDRON JI Polyhedron PD DEC 15 PY 2000 VL 19 IS 26-27 BP 2557 EP 2564 DI 10.1016/S0277-5387(00)00566-0 PG 8 WC Chemistry, Inorganic & Nuclear; Crystallography SC Chemistry; Crystallography GA 386MG UT WOS:000166065000006 ER PT J AU Hasty, R Hawthorne-Allen, AM Averett, T Barkhuff, D Beck, DH Beise, EJ Blake, A Breuer, H Carr, R Covrig, S Danagoulian, A Dodson, G Dow, K Farkhondeh, M Filippone, BW Gao, J Herda, MC Ito, TM Jones, CE Korsch, W Kramer, K Kowalski, S Lee, P McKeown, RD Mueller, B Pitt, M Ritter, J Roche, J Savu, V Spayde, DT Tieulent, R Tsentalovich, E Wells, SP Yang, B Zwart, T AF Hasty, R Hawthorne-Allen, AM Averett, T Barkhuff, D Beck, DH Beise, EJ Blake, A Breuer, H Carr, R Covrig, S Danagoulian, A Dodson, G Dow, K Farkhondeh, M Filippone, BW Gao, J Herda, MC Ito, TM Jones, CE Korsch, W Kramer, K Kowalski, S Lee, P McKeown, RD Mueller, B Pitt, M Ritter, J Roche, J Savu, V Spayde, DT Tieulent, R Tsentalovich, E Wells, SP Yang, B Zwart, T TI Strange magnetism and the anapole structure of the proton SO SCIENCE LA English DT Article ID SCATTERING; NUCLEON; MOMENT; WEAK AB The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. CALTECH, Kellogg Radiat Lab, Pasadena, CA 91125 USA. MIT, Nucl Sci Lab, Bates Linear Accelerator Ctr, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Virginia Polytech Inst & State Univ, Dept Phys, Blacksburg, VA 24061 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Louisiana Tech Univ, Dept Phys, Ruston, LA 71272 USA. Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. RP Beise, EJ (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RI Savu, Veronica/C-6069-2009; Averett, Todd/A-2969-2011; Lee, Patricia/B-6146-2012 NR 17 TC 132 Z9 134 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 15 PY 2000 VL 290 IS 5499 BP 2117 EP 2119 DI 10.1126/science.290.5499.2117 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 383ER UT WOS:000165870600048 PM 11118140 ER PT J AU Thurn-Albrecht, T Schotter, J Kastle, CA Emley, N Shibauchi, T Krusin-Elbaum, L Guarini, K Black, CT Tuominen, MT Russell, TP AF Thurn-Albrecht, T Schotter, J Kastle, CA Emley, N Shibauchi, T Krusin-Elbaum, L Guarini, K Black, CT Tuominen, MT Russell, TP TI Ultrahigh-density nanowire arrays grown in self-assembled diblock copolymer templates SO SCIENCE LA English DT Article ID ANODIC ALUMINA; ELECTRIC-FIELD; THIN-FILMS; FABRICATION; MICROSTRUCTURE; ALIGNMENT; PARTICLES AB We show a simple, robust, chemical route to the fabrication of ultrahigh-density arrays of nanopores with high aspect ratios using the equilibrium self-assembled morphology of asymmetric diblock copolymers. The dimensions and Lateral density of the array are determined by segmental interactions and the copolymer molecular weight. Through direct current electrodeposition, we fabricated vertical arrays of nanowires with densities in excess of 1.9 x 10(11) wires per square centimeter. We found markedly enhanced coercivities with ferromagnetic cobalt nanowires that point toward a route to ultrahigh-density storage media. The copolymer approach described is practical, parallel, compatible with current Lithographic processes, and amenable to multilayered device fabrication. C1 Univ Massachusetts, Dept Polymer Sci & Engn, Amherst, MA 01003 USA. Univ Massachusetts, Dept Phys, Amherst, MA 01003 USA. IBM Corp, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Russell, TP (reprint author), Univ Massachusetts, Dept Polymer Sci & Engn, Amherst, MA 01003 USA. RI Shibauchi, Takasada/B-9349-2008; Tuominen, Mark/A-6129-2012 OI Shibauchi, Takasada/0000-0001-5831-4924; NR 37 TC 1506 Z9 1521 U1 53 U2 475 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 15 PY 2000 VL 290 IS 5499 BP 2126 EP 2129 DI 10.1126/science.290.5499.2126 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 383ER UT WOS:000165870600051 PM 11118143 ER PT J AU Majidi, V Smith, RG Xu, N McMahon, MW Bossio, R AF Majidi, V Smith, RG Xu, N McMahon, MW Bossio, R TI Electrothermal vaporization, part 2: surface chemistry SO SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY LA English DT Review DE vaporization mechanisms; graphite surface chemistry; thermal desorption; metal migration; chemical reactors; catalysis ID ATOMIC-ABSORPTION SPECTROMETRY; ORIENTED PYROLYTIC-GRAPHITE; RUTHERFORD BACKSCATTERING SPECTROMETRY; SCANNING ELECTRON-MICROSCOPY; HIGH-TEMPERATURE REACTIONS; PERMANENT IRIDIUM MODIFIER; OXIDE-FORMING ELEMENTS; MASS-SPECTROMETRY; COATED GRAPHITE; ELEVATED-TEMPERATURES AB This review is the second of a two-part series on evaluation of vaporization and atomization processes in electrothermal vaporizers (ETV), focused specifically on surface chemistry in ETVs. Laser desorption mass spectrometry and differential scanning calorimetry are used to investigate vaporization of Mg, Ca, Sr, Ba, and Ni. Graphite, AI, and Ta were used as the vaporizer substrate material to elucidate potential pathways with regard to surface chemistry. The results presented in parts 1 and 2 of this publication series clearly illustrate the role of surface chemistry when a substrate is heated to yield atomic or molecular vapors. Depending on the attributes of the substrate material and the extent of surface modification, the surface-induced processes that ultimately define the quantity and the nature of gas phase species includes liquid-solid interactions, solid-solid interactions, catalysis, diffusion, migration, heterogeneous reactions and intercalation. (C) 2000 Elsevier Science B.V. AU rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Chem, Los Alamos, NM 87545 USA. Lexmark Int, Dept E05A, Lexington, KY 40550 USA. ManTech Environm Res Serv Corp, Ada, OK 74821 USA. Sealed Air Corp, Peachtree City, GA 30269 USA. Florida State Univ, Dept Chem, Tallahassee, FL 32306 USA. RP Majidi, V (reprint author), Univ Calif Los Alamos Natl Lab, Div Chem, MS K484, Los Alamos, NM 87545 USA. NR 88 TC 23 Z9 24 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0584-8547 J9 SPECTROCHIM ACTA B JI Spectroc. Acta Pt. B-Atom. Spectr. PD DEC 15 PY 2000 VL 55 IS 12 BP 1787 EP 1821 DI 10.1016/S0584-8547(00)00276-7 PG 35 WC Spectroscopy SC Spectroscopy GA 388RE UT WOS:000166194800001 ER PT J AU Hopfner, KP Tainer, JA AF Hopfner, KP Tainer, JA TI DNA mismatch repair: The hands of a genome guardian SO STRUCTURE LA English DT Article ID TRANSLOCATION MECHANISM; REPLICATION FIDELITY; STRUCTURAL BIOLOGY; CRYSTAL-STRUCTURE; MOLECULAR SWITCH; ATP HYDROLYSIS; PROTEIN MUTS; COMPLEX; CANCER; SUSCEPTIBILITY AB DNA mismatch repair (MMR) is initiated when the MutS protein recognizes damaged DNA. Crystal structures of MutS bound to mispaired and unpaired DNA show how MutS distinguishes damaged from undamaged DNA and explain how a broad variety of DNA mismatch lesions can be detected. The structures suggest mechanisms for the ATP-induced structural regulation of multistep DNA repair processes. C1 Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. Scripps Res Inst, Skaggs Inst Chem Biol, La Jolla, CA 92037 USA. Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA USA. RP Tainer, JA (reprint author), Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. RI Hopfner, Karl-Peter/B-6864-2014 OI Hopfner, Karl-Peter/0000-0002-4528-8357 NR 29 TC 15 Z9 15 U1 0 U2 0 PU CELL PRESS PI CAMBRIDGE PA 1100 MASSACHUSETTES AVE,, CAMBRIDGE, MA 02138 USA SN 0969-2126 J9 STRUCTURE JI Structure PD DEC 15 PY 2000 VL 8 IS 12 BP R237 EP R241 DI 10.1016/S0969-2126(00)00545-1 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 420TY UT WOS:000168022400002 PM 11188699 ER PT J AU Gerasimov, MR Franceschi, M Volkow, ND Rice, O Schiffer, WK Dewey, SL AF Gerasimov, MR Franceschi, M Volkow, ND Rice, O Schiffer, WK Dewey, SL TI Synergistic interactions between nicotine and cocaine or methylphenidate depend on the dose of dopamine transporter inhibitor SO SYNAPSE LA English DT Article DE dopamine; addiction; Ritalin; ADHD; microdialysis ID NUCLEUS-ACCUMBENS DOPAMINE; VENTRAL TEGMENTAL AREA; FREELY MOVING RATS; EXTRACELLULAR DOPAMINE; CAUDATE-PUTAMEN; BABOON BRAIN; HUMANS; SYSTEM; AMPHETAMINE; INCREASES AB There is a greater prevalence of cigarette smoking among cocaine-dependent individuals and hyperactive children treated with stimulants (e.g., methylphenidate, MP). However, little is known about the neurochemical basis of the interaction between nicotine and cocaine or NP. It is thought that the reinforcing effects of cocaine and MP are due partly to increases in synaptic DA in the nucleus accumbens (NAc). These measurable increases are secondary to the blockade of the DA transporter. In contrast, nicotine stimulates acetylcholine receptors located presynaptically on dopaminergic projections from the ventral tegmental area (VTA) to the NAc and increases DA transmission. Here we investigate the effects of nicotine on NAc DA in animals simultaneously injected with cocaine or MP. Coadministration of nicotine (0.4 mg/kg s.c.) and cocaine (10 mg/kg i.p.) or MP (5 mg/kg i.p.) increased the extracellular NAc DA levels in an additive manner, while coadministration of nicotine (0.4 mg/kg s.c.) and a higher dose of cocaine (20 mg/kg) or MP (10 mg/kg) clearly produced a synergistic elevation in NAc DA. These findings suggest that the degree of DA transporter (DAT) occupancy contributes to the synergistic interaction between nicotine and cocaine or MP. (C) 2000 Wiley-Liss, Inc. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. NYU, Sch Med, Dept Psychiat, New York, NY 10016 USA. RP Gerasimov, MR (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. FU NIDA NIH HHS [5RO-DA06278]; NIMH NIH HHS [MH49165]; PHS HHS [R2955155] NR 47 TC 67 Z9 67 U1 1 U2 4 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-4476 J9 SYNAPSE JI Synapse PD DEC 15 PY 2000 VL 38 IS 4 BP 432 EP 437 DI 10.1002/1098-2396(20001215)38:4<432::AID-SYN8>3.0.CO;2-Q PG 6 WC Neurosciences SC Neurosciences & Neurology GA 370XC UT WOS:000165147700008 PM 11044890 ER PT J AU Cosenza, M Gifford, AN Gatley, SJ Pyatt, B Liu, Q Makriyannis, A Volkow, ND AF Cosenza, M Gifford, AN Gatley, SJ Pyatt, B Liu, Q Makriyannis, A Volkow, ND TI Locomotor activity and occupancy of brain cannabinoid CB1 receptors by the antagonist/inverse agonist AM281 SO SYNAPSE LA English DT Article DE radioiodine; pyrazole; antagonist; cannabinoid; locomotor activity ID SR 141716A; RAT-BRAIN; IN-VIVO; ACETYLCHOLINE-RELEASE; DOPAMINE TRANSPORTER; RHESUS-MONKEYS; DELTA(9)-TETRAHYDROCANNABINOL; WITHDRAWAL; SR141716A; SLICES AB The goals of this study were to examine the relationship between intravenous doses of the cannabinoid CB1 receptor antagonist AM281 (N-(morpholin-4-yl)-5-(4-iodophenyl)- 1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide) and the degree of occupancy of this receptor, and to relate occupancy to the ability of this compound to antagonize the sedative effects of the cannabinoid receptor agonist WIN 55,212-2. Occupancy was determined by measuring the ability of intravenous doses of AM281 to inhibit in vivo binding of [I-131]AM281 in brain areas, and locomotor activity was assessed by measuring the rate of beam crossings in a photocell apparatus. As previously documented, WIN 55,212-2 (1 mg/kg, i.v.) significantly reduced locomotor activity at early times after administration. Go-injection of AM281 (0.3 mg/kg i/v) and WIN 55,212-2 restored the rate of beam crossings to that seen on injection of vehicle. In addition, AM281 (0.3 mg/kg i/v) approximately doubled locomotor activity between 60-120 min when injected alone. The IC50 value for displacement of [I-131]AM281 by AM281 was 0.45 mg/kg. These observations confirm earlier indications that AM281 is a CB1 receptor antagonist or inverse agonist and suggest the existence of an endogenous cannabinoid tone that moderates exploratory locomotor activity. (C) 2000 Wiley-Liss, Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Univ Connecticut, Dept Pharmaceut Sci & Mol & Cell Biol, Storrs, CT 06269 USA. RP Gatley, SJ (reprint author), Brookhaven Natl Lab, Dept Med, 490 Bell Ave, Upton, NY 11973 USA. FU NIDA NIH HHS [DA 07515, DA 09158, DA 12412] NR 35 TC 44 Z9 44 U1 0 U2 5 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-4476 J9 SYNAPSE JI Synapse PD DEC 15 PY 2000 VL 38 IS 4 BP 477 EP 482 DI 10.1002/1098-2396(20001215)38:4<477::AID-SYN13>3.0.CO;2-Y PG 6 WC Neurosciences SC Neurosciences & Neurology GA 370XC UT WOS:000165147700013 PM 11044895 ER PT J AU Gatley, SJ Gifford, AN Carroll, FI Volkow, ND AF Gatley, SJ Gifford, AN Carroll, FI Volkow, ND TI Sensitivity of binding of high-affinity dopamine receptor radioligands to increased synaptic dopamine SO SYNAPSE LA English DT Article DE dopamine; dopamine transporter; positron emission tomography; epidepride; SCH 23390 ID ENDOGENOUS DOPAMINE; BEHAVIORAL SENSITIZATION; NONHUMAN-PRIMATES; I-125 EPIDEPRIDE; C-11 RACLOPRIDE; RAT-BRAIN; COCAINE; INVIVO; AMPHETAMINE; RELEASE AB PET and SPECT studies have documented that D2 radioligands of moderate affinity? but not radioligands of high affinity, are sensitive to pharmacological challenges that alter synaptic dopamine levels. The objective of this work was to determine whether the brain kinetics of high-affinity radioligands for dopamine D1 ([H-3]SCH 23390) and D2 ([I-123]epidepride) receptors were altered by a prolonged elevation of synaptic dopamine induced by the potent cocaine analog RTI-55. Mice were injected intravenously with radioligands either 30 min after or 4 h before intraperitoneal administration of RTI-55 (2 mg/kg). In separate experiments, the pharmacological effects of RTI-55 were assessed biochemically by measuring uptake of dopamine in synaptosomes prepared from RTI-treated mice and behaviorally by monitoring locomotor activity. Consistent with the expected elevation of synaptic dopamine, RTI-55 induced a long-lasting decrement in dopamine uptake measured ex vivo, and a prolonged increase in locomotor activity. RTI-55 injected prior to the radioligands induced a significant(P < 0.05) increase in striatal concentration of [I-123]epidepride at 15 min, relative to saline-treated controls, but there were no differences between the two groups at later time-points. For [H-3]SCH 23390, both initial striatal uptake and subsequent clearance were slightly increased by preadministration of RTI-55. Administration of RTI-55 4 h after the radioligands (i.e., when it was presumed that a state of near equilibrium binding of the radioligands had been reached), was associated with a significant reduction of striatal radioactivity for both radiotracers. Our results are consistent with increased competition between dopamine and radioligand for binding to both D1 and D2 receptors after treatment with RTI-55. We suggest that the magnitude of the competition is reduced by failure of the receptor binding of high-affinity radioligands to rapidly attain equilibrium. (C) 2000 Wiley-Liss, Inc. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Res Triangle Inst, Res Triangle Pk, NC 27709 USA. RP Gatley, SJ (reprint author), Brookhaven Natl Lab, Dept Med, 490 Bell Ave, Upton, NY 11973 USA. NR 32 TC 9 Z9 9 U1 1 U2 1 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-4476 J9 SYNAPSE JI Synapse PD DEC 15 PY 2000 VL 38 IS 4 BP 483 EP 488 DI 10.1002/1098-2396(20001215)38:4<483::AID-SYN14>3.0.CO;2-W PG 6 WC Neurosciences SC Neurosciences & Neurology GA 370XC UT WOS:000165147700014 PM 11044896 ER PT J AU Zhou, JW Findley, BR Teslja, A Braun, CL Sutin, N AF Zhou, JW Findley, BR Teslja, A Braun, CL Sutin, N TI Ion pairs from photoexcited, "random" electron donors and accepters: Alkylbenzenes and tetracyanoethylene SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CHARGE-TRANSFER COMPLEXES; ENERGY-GAP DEPENDENCE; TRANSIENT ABSORPTION-MEASUREMENTS; ANTHRACENE SINGLE-CRYSTALS; ARYL DERIVATIVES; ACETONITRILE SOLUTION; CATION RECOMBINATION; DISTANCE DEPENDENCE; CARRIER GENERATION; COUPLING ELEMENTS AB Transient photocurrent experiments are used to measure the free radical ion quantum yield of a number of alkylbenzene electron donors with the electron acceptor tetracyanoethylene (TCNE). These experiments are performed at a variety of photoexcitation wavelengths in dichloromethane, a moderately polar solvent. It is found that the free ion yields often exhibit a very strong dependence on the excitation wavelength and may decrease markedly in the center of the charge-transfer band. For example, the free ion yield of the donor-acceptor system, pentamethylbenzene -TCNE, increases more than 100-fold when the excitation wavelength is switched from 532 to 397 nm! We show that this result and others are understandable from the following model. While closely associated electron donor-acceptor (EDA) complexes account for most of the absorption, there is an additional, usually small, absorption due to unassociated random donor and acceptor pairs. The Franck-Condon (vertical) excitation of these random pairs results in radical ion pairs which have center-to-center distances greater than contact and which have high probabilities for separation. Quantitative analysis based on Onsager theory indicates that only distantly separated radical ion pairs (ca. I nm or more) created by photoexcitation can escape each other's Coulombic attraction to produce the free ion yields observed in our experiments. The photoexcitation of ground-state EDA complexes plays little essential role in this process. The observed wavelength dependence then corresponds both to variation in the ratio of random pair to EDA complex absorption and to the distance distribution of radical ion pairs produced. Free ion yields calculated using Onsager theqry and a simple excitation function for the random pairs fit our experimental results quite well and support this model. C1 Dartmouth Coll, Dept Chem, Burke Lab 6128, Hanover, NH 03755 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Braun, CL (reprint author), Dartmouth Coll, Dept Chem, Burke Lab 6128, Hanover, NH 03755 USA. NR 80 TC 19 Z9 19 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD DEC 14 PY 2000 VL 104 IS 49 BP 11512 EP 11521 DI 10.1021/jp003005r PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 383DQ UT WOS:000165868200007 ER PT J AU Clifford, EP Farrell, JT DeSain, JD Taatjes, CA AF Clifford, EP Farrell, JT DeSain, JD Taatjes, CA TI Infrared frequency-modulation probing of product formation in alkyl plus O-2 reactions: I. The reaction of C2H5 with O-2 between 295 and 698 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ARRHENIUS PARAMETERS; PRESSURE-DEPENDENCE; REACTION-MECHANISM; ETHANE COMBUSTION; REACTION-KINETICS; PEROXY-RADICALS; ETHYL RADICALS; HCL PRODUCTION; GAS-PHASE; HO2 AB The production of HO2 in the reaction of ethyl radicals with molecular oxygen has been investigated using laser photolysis/cw infrared frequency modulation spectroscopy. The ethyl radicals are formed by reaction of photolytically produced Cl atoms with ethane, initiated via pulsed laser photolysis of Cl-2 and the progress of the reaction is monitored by frequency-modulation spectroscopy of the HO2 product. The yield of HO2 in the reaction is measured by comparison with the Cl-2/CH3OH/O-2 system, which quantitatively converts Cl atoms to HO2. At low temperatures stabilization to C2H5O2 dominates, but at elevated temperatures (> 575 K) dissociation of the ethylperoxy radical begins to contribute. Biexponential time behavior of the HO2 production allows separation of prompt, "direct" HO2 formation from HO2 produced after thermal redissociation of an Initial ethylperoxy adduct, The prompt HO2 yield exhibits a smooth increase with increasing temperature, but the total HO2 yield, which includes contributions from the redissociation of ethylperoxy radicals, rises sharply from similar to 10% to 100% between 575 and 675 K. Because of the separation of time scales in the HO2 production, this rapid rise can unambiguously be assigned to ethylperoxy dissociation. No OH was observed in the reaction, and an upper limit of 6% can be placed on direct OH formation from the C2H5 + O-2 reaction at 700 K. The time behavior of the HO2 production is at variance with the predictions of Wagner et al.'s RRKM-based parameterization of this reaction (J. Phys. Chem. 1990, 94, 1853). However, a simple ad hoc correction to that model, which takes into account a recent reinterpretation of the equilibrium constant for C2H5 + O-2 Ct C2H5O2, predicts yields and time constants consistent with the present measurements. The reaction mechanism is further discussed in terms of recent quantum chemical and master equation studies of this system, which show that the present results are well described by a coupled mechanism with HO2 + C2H4 formed by direct elimination from the C2H5O2 adduct. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Taatjes, CA (reprint author), Sandia Natl Labs, Combust Res Facil, Mail Stop 9055, Livermore, CA 94551 USA. NR 45 TC 62 Z9 62 U1 1 U2 13 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 DEC 14 PY 2000 VL 104 IS 49 BP 11549 EP 11560 DI 10.1021/jp0024874 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 383DQ UT WOS:000165868200011 ER PT J AU Fulton, JL Hoffmann, MM Darab, JG Palmer, BJ Stern, EA AF Fulton, JL Hoffmann, MM Darab, JG Palmer, BJ Stern, EA TI Copper(I) and copper(II) coordination structure under hydrothermal conditions at 325 degrees C: An X-ray absorption fine structure and molecular dynamics study SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SUPERCRITICAL WATER; AQUEOUS-SOLUTIONS; ION; CHLORIDE; EXAFS; HYDRATION; SPECTROSCOPY; COMPLEXES; SPECTRA; XAFS AB X-ray absorption fine structure (XAFS) spectroscopy Was used to measure the coordination structure about Cu2+, Cu1+, and Br- in water at temperatures up to 325 degreesC. The hexaaqua CU2+ species maintains its distorted octahedral structure up to 325 degreesC, whereas at higher temperatures, dehydration reactions occur producing CuO. Under reducing conditions, the dibromo Cu1+ species, [CuBr2](-), is predominant at 200 degreesC and above for systems having excess Br-. Even for a very high salt concentration of 2.0 m NaBr, only the dibromo Cu1+ species,[CuBr2](-), is observed with no evidence of higher Br- coordination. For this dibromo-species there are no tightly bound hydration waters in the first shell. In the absence of excess Br-, a monoaqua monobromo Cu1+ species, [Cu(H2O)Br] is observed. For certain systems, both Cu and Br XAFS were acquired, and a global model was used to fit the two independent sets of XAFS data. Thus, the results represent a complete picture of the coordination structure about Cu1+ including the coordination numbers, distances for the ion-ion and water-ion associations and also a high-quality measurement of the binding strength and amount of disorder (Debye-Waller factor and the anharmonicity) of the Cu1+/Br- association. Molecular dynamics (MD) simulations were used to further explore the structure and the binding forces for the [CuBr2](-) species under hydrothermal conditions. We found quantitative agreement for the Cu-Br interactions, but the simulation has difficulty predicting the experimental Cu-H2O interaction. Ln particular, the amount of scattering from the water in the dibromo Cu1+ complex was highly over-predicted, so that it is clear that simple intermolecular potential models do not adequately capture this structural feature. C1 Pacific NW Natl Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. RP Fulton, JL (reprint author), Pacific NW Natl Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. NR 38 TC 78 Z9 81 U1 3 U2 24 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD DEC 14 PY 2000 VL 104 IS 49 BP 11651 EP 11663 DI 10.1021/jp001949a PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 383DQ UT WOS:000165868200024 ER PT J AU Fontenot, CJ Wiench, JW Pruski, M Schrader, GL AF Fontenot, CJ Wiench, JW Pruski, M Schrader, GL TI Vanadia gel synthesis via peroxovanadate precursors. 1. In situ laser Raman and V-51 NMR characterization of the gelation process SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID AQUEOUS-SOLUTION; PEROXO COMPLEXES; CHEMISTRY AB Vanadium oxide gels derived from aqueous solutions of V2O5 and H2O2 have been investigated using in situ V-51 NMR and laser Raman spectroscopic techniques. On the basis of this characterization, a pathway for peroxovanadate decomposition has been proposed, including the presence of two peroxovanadate dimers. New Raman bands and assignments for these species are reported. Gelation was observed to begin both during and after the peroxovanadate decomposition, depending on the initial molar ratios of H2O2/V and the total concentration of vanadium. Experimental V-51 NMR evidence suggested that the VO2+ species was directly involved in the formation of the gel. C1 Iowa State Univ Sci & Technol, Dept Chem Engn, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Ames Lab, USDOE, Ames, IA 50011 USA. RP Schrader, GL (reprint author), Iowa State Univ Sci & Technol, Dept Chem Engn, Ames, IA 50011 USA. NR 32 TC 73 Z9 73 U1 2 U2 32 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 14 PY 2000 VL 104 IS 49 BP 11622 EP 11631 DI 10.1021/jp0021897 PG 10 WC Chemistry, Physical SC Chemistry GA 383DU UT WOS:000165868500007 ER PT J AU Liang, L Rieke, PC Fryxell, GE Liu, J Engehard, MH Alford, KL AF Liang, L Rieke, PC Fryxell, GE Liu, J Engehard, MH Alford, KL TI Temperature-sensitive surfaces prepared by UV photografting reaction of photosensitizer and N-isopropylacrylamide SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MEMBRANES; PHOTOPOLYMERIZATION; POLYMERIZATION; PLATE AB A thermal-sensitive surface was prepared on the surface of a silicone wafer (substrate) by an ultraviolet photografting reaction between a photosensitizer, (N,N'-diethylamino)ditkiocarbamoylpropyl(trimethoxy)silane, and N-isopropylacrylamide. Ellipsometery measurement revealed a thin grafting layer (similar to 44 Angstrom) consisting of a single terminal poly(N-isopropylacrylamide) (PNIPAAm) chain on the surface of the silicone wafers. X-ray photoelectron spectroscopy confirmed that the grafting layer was composed of the PNIPAAm structure. The properties of the grafting layer can be adjusted and manipulated by varying the photopolymerization time and the concentration of the monomer. Increasing the photopolymerization time and the concentration of the monomer increases both the thickness of the grafting layer and the wettability of the surface. The characteristics of the temperature-sensitive surface were investigated by dynamic contact angle as a function of temperature. The remarkable change on advancing contact angle can be observed around 32 degreesC. Compared with the substrate grafted by PNIPAAm gel, the substrate with a signal-terminal PNIPAAm chain exhibited a lower transition temperature and a narrower change range of transition temperature. This can be attributed to the mobile PNIPAAm chain with a single-terminal mode, which increases the characteristics of faster response to the temperature change. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Liang, L (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. NR 33 TC 41 Z9 44 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 14 PY 2000 VL 104 IS 49 BP 11667 EP 11673 DI 10.1021/jp9939017 PG 7 WC Chemistry, Physical SC Chemistry GA 383DU UT WOS:000165868500013 ER PT J AU Jankowiak, R Zazubovich, V Ratsep, M Matsuzaki, S Alfonso, M Picorel, R Seibert, M Small, GJ AF Jankowiak, R Zazubovich, V Ratsep, M Matsuzaki, S Alfonso, M Picorel, R Seibert, M Small, GJ TI The CP43 core antenna complex of photosystem II possesses two quasi-degenerate and weakly coupled Q(y)-trap states SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PHOTOSYNTHETIC REACTION CENTERS; HOLE-BURNING SPECTROSCOPY; PRIMARY CHARGE SEPARATION; LOW-TEMPERATURE; ENERGY-TRANSFER; GREEN PLANTS; RHODOBACTER-SPHAEROIDES; CHLOROBIUM-TEPIDUM; BINDING PROTEINS; PURPLE BACTERIA AB The CP43 chlorophyll a-core protein complex plays an important role in funneling excitation energy absorbed by more peripheral antenna complexes of photosystem II (PSII) to the reaction center (RC). Identification and characterization of the lowest energy Q(y)-states of CP33 is important for understanding the kinetics of excitation energy transfer (EET) from CP43 to the RC. We report the results of several types of spectroscopic experiments performed at liquid He temperatures on the isolated CP43 complex from spinach. Nonphotochemical hole burning (NPHB) and triplet bottleneck hole burning spectroscopies as well as zero-phonon hole (ZPH) action and Stark hole burning spectroscopies were employed. Two quasi-degenerate trap states at 682.9 nm (B state) and 683.3 nm (A state) are identified. The widths of their mainly inhomogeneously broadened Q(y)-absorption bands are 45 and 120 cm(-1), respectively. The uncorrelated site excitation distribution functions (SDF) of the two states are nearly the same as their absorption bands since the electron-phonon coupling is weak (optical reorganization energies of similar to6 cm(-1)). The NPHB spectra establish that the B state is the primary trap for EET from higher energy Q(y)-states. The permanent dipole moment change (Delta mu) of the S-0 --> Q(y) transition for both the B and A states is small, f.Delta mu = 0.25 +/- 0.05 and 0.47 +/- 0.05, respectively, where fis the local field correction factor. These values, together with the weak electron-phonon coupling and other results, indicate that both states are highly localized on a single Chi a molecule. Holewidth measurements led to the remarkable finding that the rates of A --> B and B --> A EET processes are extremely slow, similar to (6 ns)(-1). This suggests that the Chi a molecules of the two states belong to different layers of Chi a molecules located at opposite sides of the membrane. The intriguing question of why CP43 possesses two quasi-degenerate trap states that are so weakly coupled is addressed. The possibility that they play a role in the photoinhibitory and photoregulatory processes is raised. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. CSIC, EE Aula Dei, E-50080 Zaragoza, Spain. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Jankowiak, R (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI PICOREL, RAFAEL/K-7930-2014; Alfonso, Miguel/L-6970-2014 OI PICOREL, RAFAEL/0000-0003-3791-129X; Alfonso, Miguel/0000-0002-8190-5156 NR 57 TC 47 Z9 48 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 14 PY 2000 VL 104 IS 49 BP 11805 EP 11815 DI 10.1021/jp0025431 PG 11 WC Chemistry, Physical SC Chemistry GA 383DU UT WOS:000165868500031 ER PT J AU Rice, JE Fournier, KB Goetz, JA Marmar, ES Terry, JL AF Rice, JE Fournier, KB Goetz, JA Marmar, ES Terry, JL TI X-ray observations of 2l-nl ' transitions and configuration-interaction effects from Kr, Mo, Nb and Zr in near neon-like charge states from tokamak plasmas SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ALCATOR-C-MOD; KRYPTON RESONANCE LINES; ENERGY-LEVELS; PRECISION-MEASUREMENT; 2-3 TRANSITIONS; COMPLEX SPECTRA; SELF-ENERGY; FE-XVII; IONS; MOLYBDENUM AB X-ray spectra of 2l-3l' transitions in the elements krypton (Z = 36), zirconium (Z = 40), niobium (Z = 41) and molybdenum (Z = 42) from charge states around neon-like have been observed from Alcator C and Alcator C Mod plasmas. Accurate wavelengths (+/-0.5 m Angstrom) have been determined with reference to neighbouring aluminium, silicon, sulfur, chlorine and argon lines with relatively well known wavelengths. Line identifications have been made by comparison to ab initio atomic structure calculations, using a fully relativistic, parametric potential code. Calculated wavelengths and oscillator strengths are presented for 2l-3l' transitions in neon-like ions and neighbouring Na-, Mg-, F- and O-like satellites. Electric quadrupole transitions in neon-like ions of the form 3s-3d and 2p-3p are found to be relatively bright, acid their measured intensities agree well with the results of collisional-radiative modelling. The 2p-3s magnetic quadrupole transition is also relatively intense in the absence of collisional de-excitation at tokamak densities (10(13)-10(15) cm(-3)). For krypton, transitions with upper levels up to n = 9 have been observed, and the measured wavelengths and intensities have been compared with calculations. For some neon-like transitions with nearly degenerate upper levels, there can be substantial configuration interaction which alters the line intensities. C1 MIT, Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rice, JE (reprint author), MIT, Plasma Sci & Fus Ctr, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 44 TC 26 Z9 26 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD DEC 14 PY 2000 VL 33 IS 23 BP 5435 EP 5462 DI 10.1088/0953-4075/33/23/315 PG 28 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 389WD UT WOS:000166260900015 ER PT J AU Lim, SJ Lopez-Berestein, G Hung, MC Lupu, R Tari, AM AF Lim, SJ Lopez-Berestein, G Hung, MC Lupu, R Tari, AM TI Grb2 downregulation leads to Akt inactivation in heregulin-stimulated and ErbB2-overexpressing breast cancer cells SO ONCOGENE LA English DT Article DE Grb2; heregulin; ErbB2; Akt; breast cancer ID PROTEIN-KINASE-B; RECEPTOR TYROSINE KINASES; MAMMARY EPITHELIAL-CELLS; MAP KINASE; PHOSPHATIDYLINOSITOL 3-KINASE; SIGNAL-TRANSDUCTION; GROWTH-FACTOR; TUMOR-CELLS; ACTIVATION; RAS AB ErbB2 can be activated by its own overexpression or be transactivated by the heregulin polypeptide growth factor. Activation of ErbB2 leads to breast cancer cell proliferation, presumably by inducing the activation of extracellular signal-regulated kinases 1,2 (Erk1,2) and Akt. We have previously reported that the growth factor receptor bound protein-2 (Grb2) is required for the proliferation of ErbB2-overexpressing breast cancer cells. We investigated here whether Grb2 protein plays a role in heregulin-stimulated proliferation. Grb2 protein inhibition led to growth inhibition of heregulin-stimulated breast cancer cells, but not Erk1,2 inactivation. These findings are similar to our earlier observations in ErbB2-overexpressing cells. Since Akt can also be activated by heregulin, the effects of Grb2 inhibition on Akt were examined. Akt was inactivated following Grb2 downregulation in heregulin-stimulated breast cancer cells. We then examined the effects of Grb2 downregulation on Akt in ErbB2-overexpressing cells in the absence of heregulin, Similar to heregulin-stimulated cells, Grb2 inhibition also led to Akt inactivation in ErbB2-over-expressing breast cancer cells. Our results indicate that the activation of ErbB2 by heregulin or by its overexpression requires Grb2 to stimulate the Akt pathway to propagate mitogenic signals. C1 Univ Texas, MD Anderson Canc Ctr, Dept Bioimmunotherapy, Sect Immunobiol & Drug Carriers, Houston, TX 77030 USA. Univ Texas, MD Anderson Canc Ctr, Dept Mol & Cellular Oncol, Houston, TX 77030 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Tari, AM (reprint author), Univ Texas, MD Anderson Canc Ctr, Dept Bioimmunotherapy, Sect Immunobiol & Drug Carriers, Box 60, Houston, TX 77030 USA. NR 54 TC 31 Z9 34 U1 0 U2 1 PU NATURE PUBLISHING GROUP PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD DEC 14 PY 2000 VL 19 IS 54 BP 6271 EP 6276 DI 10.1038/sj.onc.1204014 PG 6 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 388YK UT WOS:000166210500010 PM 11175341 ER PT J AU Kronfeld, AS Simone, JN AF Kronfeld, AS Simone, JN TI Computation of Lambda and lambda(1) with lattice QCD (vol 490, pg 228, 2000) SO PHYSICS LETTERS B LA English DT Correction C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Kronfeld, AS (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 1 TC 11 Z9 11 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 DEC 14 PY 2000 VL 495 IS 3-4 BP 441 EP 442 DI 10.1016/S0370-2693(00)01277-6 PG 2 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 387AR UT WOS:000166098400027 ER PT J AU Taylor, MA Wingate, BA Vincent, RE AF Taylor, MA Wingate, BA Vincent, RE TI An algorithm for computing Fekete points in the triangle SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE triangle; Lebesgue constant; Fekete points; multivariate approximation ID POLYNOMIAL INTERPOLATION; SIMPLEX AB On the line and its tensor products, Fekete points are known to be the Gauss Lobatto quadrature points. But unlike high-order quadrature, Fekete points generalize to non-tensor-product domains such as the triangle. Thus Fekete points might serve as an alternative to the Gauss Lobatto points for certain applications. In this work we present a new algorithm to compute Fekete points and give results up to degree 19 for the triangle. For degree d> 10 these points have the smallest Lebesgue constant currently known. The computations validate a conjecture of Bos [J. Approx. Theory, 64 (1991), pp. 271-280] that Fekete points along the boundary of the triangle are the one-dimensional Gauss Lobatto points. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Natl Ctr Atmospher Res, Significant Opportun Atmospher Res & Sci, Boulder, CO 80307 USA. RP Taylor, MA (reprint author), Univ Calif Los Alamos Natl Lab, MS D413, Los Alamos, NM 87544 USA. NR 16 TC 96 Z9 98 U1 2 U2 5 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD DEC 14 PY 2000 VL 38 IS 5 BP 1707 EP 1720 DI 10.1137/S0036142998337247 PG 14 WC Mathematics, Applied SC Mathematics GA 389AG UT WOS:000166214900016 ER PT J AU Giraldo, O Marquez, M Brock, SL Suib, SL Hillhouse, H Tsapatsis, M AF Giraldo, O Marquez, M Brock, SL Suib, SL Hillhouse, H Tsapatsis, M TI Spontaneous formation of inorganic helical fibers and rings SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID OCTAHEDRAL MOLECULAR-SIEVES; MESOPOROUS SILICA; CATALYSTS; ZEOLITE; OXIDES; OXIDATION AB Helical fibers of porous manganese oxide have been prepared from colloidal solutions. Such fibers have diameters ranging from several mm to the micrometer range. These helices are formed, starting from a well-mixed colloidal precursor and applying no external forcing other than its confinement in a capillary or beaker and heating for a period of time. Structural changes occur during gelation, leading from an amorphous to a layered structure. The layered structure can be ion-exchanged with hard cation template ions and then heated to form tunnel structure materials that retain the helical morphology. The helices are semiconductors and permeable. As the concentration of the colloidal precursor is lowered, helices are no longer formed, but instead, two-dimensional rings are produced. The formation process of these helices is related to contraction of the gel during heating with capillary pressure until solvent is removed followed by expansion of the helix. C1 Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. Univ Massachusetts, Dept Chem Engn, Amherst, MA 01003 USA. Univ Massachusetts, Inst Mat Sci, Amherst, MA 01003 USA. Univ Massachusetts, Goessmann Lab 159, Dept Chem Engn, Amherst, MA 01003 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST DO, Los Alamos, NM 87545 USA. RP Suib, SL (reprint author), Univ Connecticut, Dept Chem, U-60, Storrs, CT 06269 USA. OI Giraldo Osorio, Oscar Hernan/0000-0002-9213-6348; Brock, Stephanie/0000-0002-0439-302X NR 33 TC 28 Z9 29 U1 4 U2 24 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 DEC 13 PY 2000 VL 122 IS 49 BP 12158 EP 12163 DI 10.1021/ja0018872 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 383CW UT WOS:000165866400011 ER PT J AU Rodriguez, JA Jirsak, T Perez, M Chaturvedi, S Kuhn, M Gonzalez, L Maiti, A AF Rodriguez, JA Jirsak, T Perez, M Chaturvedi, S Kuhn, M Gonzalez, L Maiti, A TI Studies on the behavior of mixed-metal oxides and desulfurization: Reaction of H2S and SO2 with Cr2O3(0001), MgO(100), and CrxMg1-xO(100) SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; SOLID-SOLUTION CATALYSTS; AB-INITIO CALCULATIONS; BAND-GAP SIZE; MOLECULAR-DYNAMICS; CHEMICAL-REACTIVITY; SURFACES; ADSORPTION; SULFUR AB In environmental catalysis the removal or destruction of S-containing molecules is a very important issue nowadays. The interaction of H2S and SO2 with Cr2O3(0001), MgO(100) and CrxMg1-x(100) surfaces (x = 0.05-0.08) was studied using synchrotron-based high-resolution photoemission. X-ray absorption near edge spectroscopy (XANES) was used to examine the chemistry of the molecules on powders of Cr2O3, MgO and CrxMg1-xO catalysts. The activity toward the breaking of S-H and S-O bonds was found to increase in the sequence: MgO < Cr2O3 < CrxMg1-xO. The mixed-metal oxide displays a unique ability for breaking S-O bonds that makes it the best catalyst for the Claus process (2H(2)S + SO2 --> 2H(2)O + 3S(solid)) and the reduction of; SO2 by CO (S-2 + 2CO --> 2CO(2) + S-solid) First-principles density-functional (DF-GGA) calculations revealed that the superior catalytic properties of the mixed-metal oxide are due to the special electronic properties of Cr cations contained ina matrix of MgO. These Cr atoms have a lower oxidation state than the atoms in Cr2O3, and exhibit occupied 3d levels that are less stable than the valence bands of MgO. Both properties favor interactions with the LUMO of SO2 (S-O antibonding) and the subsequent dissociation of the molecule. The behavior of the CrxMg1-xO system illustrates a fundamental principle for the design of mixed-metal oxide catalysts. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11953 USA. Cent Univ Venezuela, Fac Ciencias, Caracas 1020A, Venezuela. Mol Simulat Inc, San Diego, CA 92121 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11953 USA. NR 82 TC 51 Z9 51 U1 4 U2 26 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 DEC 13 PY 2000 VL 122 IS 49 BP 12362 EP 12370 DI 10.1021/ja003149j PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 383CW UT WOS:000165866400036 ER PT J AU Kawaguchi, T Yasuda, H Shimazu, K Porter, MD AF Kawaguchi, T Yasuda, H Shimazu, K Porter, MD TI Electrochemical quartz crystal microbalance investigation of the reductive desorption of self-assembled monolayers of alkanethiols and mercaptoalkanoic acids on Au SO LANGMUIR LA English DT Article ID SINGLE-CRYSTAL; FERROCENYLUNDECANETHIOL MONOLAYER; AU(111) ELECTRODES; GOLD ELECTRODE; SURFACES; 11-FERROCENYL-1-UNDECANETHIOL; OXIDATION; ION; ADSORPTION; KINETICS AB The reductive desorption of self-assembled monolayers (SAMs) of alkanethiols and mercaptoalkanoic acids from gold has been examined in various alkaline solutions and supporting electrolytes using an electrochemical quartz crystal microbalance (EQCM). The desorption exhibits two voltammetric waves: a large dominant wave and another smaller wave at more negative potentials. The appearance of two waves is due to the heterogeneity in the substrate crystallinity and/or in the packing state of the thiol molecules. The desorption charge is calculated after consideration of the charge required to establish the double layer of the uncoated electrode. The mass change per mole of electrons (mpe) for desorption is determined by comparing the frequency change with the total charge passed upon desorption. The mpe increases linearly with the chain length and has a slope close to the mass of CH2, as is expected for a one-electron process. In the case of alkanethiol desorption, however, the mpe is much smaller than the molar mass of the desorbed alkanethiol. This difference is attributed to the simultaneous adsorption of cation species from solution, which is supported by the observed cation dependence of mpe. We estimated the molar mass of the desorbed mercaptoalkanoic acid by summing the mass of this cation species and the mpe for the mercaptoalkanoic acid SAM. From the value thus calculated, we conclude that the terminal carboxylate of the SAM is associated with the solvated cation. The solvation numbers are determined to be 1.6, 2.4-3.0, and 0.2 for Li+, K+, and Cs+, respectively. C1 Hokkaido Univ, Grad Sch Environm Earth Sci, Div Mat Sci, Sapporo, Hokkaido 0600810, Japan. Iowa State Univ, Microanalyt Instrumentat Ctr, USDA, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Shimazu, K (reprint author), Hokkaido Univ, Grad Sch Environm Earth Sci, Div Mat Sci, Sapporo, Hokkaido 0600810, Japan. RI Shimazu, Katsuaki/D-4282-2013 NR 54 TC 103 Z9 103 U1 5 U2 40 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 12 PY 2000 VL 16 IS 25 BP 9830 EP 9840 DI 10.1021/la000756b PG 11 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 380VM UT WOS:000165724200025 ER PT J AU Zamlynny, V Burgess, I Szymanski, G Lipkowski, J Majewski, J Smith, G Satija, S Ivkov, R AF Zamlynny, V Burgess, I Szymanski, G Lipkowski, J Majewski, J Smith, G Satija, S Ivkov, R TI Electrochemical and neutron reflectivity studies of spontaneously formed amphiphilic surfactant bilayers at the gold-solution interface SO LANGMUIR LA English DT Article ID AU(111) ELECTRODE; ADSORPTION; MONOLAYERS; DIFFUSION; PYRIDINE AB We have employed electrochemical and neutron reflectivity measurements to study the transfer of 4-pentadecyl-pyridine (C15-4Py), an insoluble amphiphilic surfactant, from the gas-solution (G-S) interface to the metal-solution IM-S) interface of a Au(lll) electrode. Neutron reflectivity experiments have demonstrated that C15-4Py forms a bilayer at the Au(111) electrode surface. Electrochemical experiments demonstrated that this bilayer is formed spontaneously when the electrode surface is brought in contact with the film-covered G-S interface. The surfactant molecules can move from the G-S to the M-S interface across the triple-phase boundary formed where the metal, solution, and gas phases are in contact. Time-dependence experiments have shown that the spreading process is irreversible. Having formed a bilayer or monolayer at the M-S interface, the C15-4Py surfactant molecules do not move back to a film-free G-S interface. Three models were used to analyze the kinetics of spreading. Our results are best explained assuming that the spreading is a first-order surface reaction controlled by the activation barrier that the surfactant molecules have to overcome when crossing the triple-phase line. C1 Univ Guelph, Dept Chem & Biochem, Guelph, ON N1G 2W1, Canada. Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr 12, Los Alamos, NM 87545 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Lipkowski, J (reprint author), Univ Guelph, Dept Chem & Biochem, Guelph, ON N1G 2W1, Canada. RI Lujan Center, LANL/G-4896-2012; Ivkov, Robert/A-3902-2015 OI Ivkov, Robert/0000-0002-2930-5276 NR 22 TC 18 Z9 18 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 12 PY 2000 VL 16 IS 25 BP 9861 EP 9870 DI 10.1021/la000022z PG 10 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 380VM UT WOS:000165724200029 ER PT J AU Liang, L Liu, J Gong, XY AF Liang, L Liu, J Gong, XY TI Thermosensitive poly(N-isopropylacrylamide)-clay nanocomposites with enhanced temperature response SO LANGMUIR LA English DT Article ID N-ISOPROPYLACRYLAMIDE; GRAFT-COPOLYMERS; GEL; HYDROGELS; RELEASE; MONTMORILLONITE; MEMBRANES; BEHAVIOR; POLYMERS; SURFACE AB This paper reports a thermosensitive polymer-clay nanocomposite with enhanced temperature response based on organically modified clay-poly(N-isopropylacrylamide) (PNIPAAm) nanocomposites. Compared with previously reported polymer-clay nanocomposites, the interfacial chemistry between the clay minerals and the polymer in the new nanocomposite is modified through a coupling agent to favor a more efficient thermal transition. This material exhibits an unusually large thermal volumetric change and faster transition kinetics as compared to conventional PNIPAAm gels. These results are contrary to what has been observed in a PNIPAAm-clay nanocomposite, in which the polymer molecules interact directly with the hydrophilic silicate clays. X-ray diffraction and transmission electron microscopy suggest that the clay minerals in the nanocomposite are partially intercalated and partially exfoliated in the dried state and mostly exfoliated in the swollen state. The enhanced thermal response and increased release rate are desirable for a range of applications, including sensors, actuators, regulators, and controlled release devices. The different results obtained in different nanocomposites point to a new approach to finely tune the thermal transition by controlling the interfacial interactions between the polymers and the nanophase materials. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Liu, J (reprint author), Pacific NW Natl Lab, 902 Battelle Blvd,POB 999, Richland, WA 99352 USA. NR 42 TC 92 Z9 102 U1 6 U2 31 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 12 PY 2000 VL 16 IS 25 BP 9895 EP 9899 DI 10.1021/la000279v PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 380VM UT WOS:000165724200033 ER PT J AU Rose, J Moulin, I Hazemann, JL Masion, A Bertsch, PM Bottero, JY Mosnier, F Haehnel, C AF Rose, J Moulin, I Hazemann, JL Masion, A Bertsch, PM Bottero, JY Mosnier, F Haehnel, C TI X-ray absorption spectroscopy study of immobilization processes for heavy metals in calcium silicate hydrates: 1. Case of lead SO LANGMUIR LA English DT Article ID BOND-VALENCE DETERMINATION; POWDER PROFILE REFINEMENT; PORTLAND-CEMENT; SORPTION PRODUCTS; CRYSTAL-STRUCTURE; XAFS; SPECTRA; NITRATE; PB(II); OXIDES AB Trace amounts of heavy metals can be detected in cement. The major source is due to heavy metals naturally present in some of the raw materials used for clinkers manufacture. One way to predict the long-term behavior of these metals is to know which types of links occur between heavy metals and major elements (Ca, Si, Al, Fe). Since tricalcium silicate (C(3)S) is the major phase of cement-base material, a XAS study at the Pb-LIII edge has been carried out to elucidate the binding mechanisms of Pb by calcium silicate. At low concentration, under the precipitation of the oxide and oxy-hydroxide, a strong retardation of the hydration of the C(3)S has been observed for C(3)S doped with Pb. EXAFS results confirmed by XANES at the Pb-LIII edge indicate that Pb is chemically adsorbed at the surface of the C(3)S. This Pb layer acts as a diffusional barrier to water and leads to the retardation of C(3)S hydration. When C(3)S is previously hydrated without Pb, lead is strongly retained by the hydrated C(3)S (called CSH for calcium silicate hydrate). A previous (29)Si NMR(1) study has demonstrated that Pb is chemically fixed to the CSH structure through a Pb-O-Si bond. XAS experiments have confirmed that Pb is incorporated within the matrix of CSH and directly linked at the end of the silicate chains through Pb-O-Si bonds. The Pb-Si distance is approximate to 13.75 Angstrom. All EXAFS results have been confirmed by ab initio calculation including multiple scattering. C1 Univ Aix Marseille 3, CEREGE, Equipe Physicochim Interfaces, CNRS,UMR 6635,Europole Mediterraneen Arbois, F-13545 Aix En Provence 4, France. CNRS, Cristallog Lab, F-38042 Grenoble 9, France. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. CIRSEE, F-78230 Le Pecq, France. ATILH, F-92974 Paris, France. RP Rose, J (reprint author), Univ Aix Marseille 3, CEREGE, Equipe Physicochim Interfaces, CNRS,UMR 6635,Europole Mediterraneen Arbois, BP80, F-13545 Aix En Provence 4, France. EM rose@cerege.fr NR 31 TC 32 Z9 32 U1 5 U2 21 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 12 PY 2000 VL 16 IS 25 BP 9900 EP 9906 DI 10.1021/la0005208 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 380VM UT WOS:000165724200034 ER PT J AU Wilcoxon, JP Martin, JE Provencio, P AF Wilcoxon, JP Martin, JE Provencio, P TI Size distributions of gold nanoclusters studied by liquid chromatography SO LANGMUIR LA English DT Article ID COLLOIDAL SEMICONDUCTORS; CLUSTERS; PHOTOCHEMISTRY; PARTICLES; MOLECULES; METAL AB We report high-pressure liquid chromatography (HPLC) and transmission electron microscopy (TEM) studies of the size distributions of nanosize gold clusters dispersed in organic solvents. These metal clusters are synthesized in inverse micelles at room temperature, and those investigated range in diameter from 1 to 10 nm. HPLC is sensitive enough to discern changes in hydrodynamic volume corresponding to only 2 carbon atoms of the passivating agent or metal core size changes of less than 4 Angstrom. We have determined for the first time how the total cluster volume (metal core + passivating organic shell) changes with the size of the passivating agent. C1 Sandia Natl Labs, Dept 1122, Dept Chem, Albuquerque, NM 87185 USA. RP Wilcoxon, JP (reprint author), Sandia Natl Labs, Dept 1122, Dept Chem, POB 5800, Albuquerque, NM 87185 USA. NR 19 TC 137 Z9 137 U1 2 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD DEC 12 PY 2000 VL 16 IS 25 BP 9912 EP 9920 DI 10.1021/la000669j PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 380VM UT WOS:000165724200036 ER PT J AU Clancy, TC Putz, M Weinhold, JD Curro, JG Mattice, WL AF Clancy, TC Putz, M Weinhold, JD Curro, JG Mattice, WL TI Mixing of isotactic and syndiotactic polypropylenes in the melt SO MACROMOLECULES LA English DT Article ID INTEGRAL-EQUATION THEORY; MOLECULAR-DYNAMICS SIMULATIONS; X-RAY-SCATTERING; ATHERMAL POLYMER BLENDS; PHASE-EQUILIBRIA; LIQUIDS; CHAINS; THERMODYNAMICS; LATTICE; MORPHOLOGY AB The miscibility of polypropylene (PP) melts in which the chains differ only in stereochemical composition has been investigated by two different procedures. One approach used detailed local information from a Monte Carlo simulation of a single chain, and the other approach takes this information from a rotational isomeric state model devised decades ago, for another purpose. The first approach uses PRISM theory to deduce the intermolecular packing in the polymer blend, while the second approach uses a Monte Carlo simulation of a coarse-grained representation of independent chains, expressed on a high-coordination lattice. Both approaches find a positive energy change upon mixing isotactic PP (iPP) and syndiotactic PP (sPP) chains in the melt. This conclusion is qualitatively consistent with observations published recently by Mulhaupt and co-workers. The size of the energy change on mixing is smaller in the MC/PRISM approach than in the RIS/MC simulation, with the smaller energy change being in better agreement with the experiment. The RIS/MC simulation finds no demixing for iPP and atactic polypropylene (aPP) in the melt, consistent with several experimental observations in the literature. The demixing of the iPP/sPP blend may arise from attractive interactions in the sPP melt that are disrupted when the sPP chains are diluted with aPP or iPP chains. C1 Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. Univ Akron, Inst Polymer Sci, Akron, OH 44325 USA. RP Curro, JG (reprint author), Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. NR 38 TC 54 Z9 56 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD DEC 12 PY 2000 VL 33 IS 25 BP 9452 EP 9463 DI 10.1021/ma0011035 PG 12 WC Polymer Science SC Polymer Science GA 382PF UT WOS:000165830900042 ER PT J AU Fein, G Di Sclafani V Tanabe, J Cardenas V Weiner, MW Jagust, WJ Reed, BR Norman, D Schuff, N Kusdra, L Greenfield, T Chui, H AF Fein, G Di Sclafani, V Tanabe, J Cardenas, V Weiner, MW Jagust, WJ Reed, BR Norman, D Schuff, N Kusdra, L Greenfield, T Chui, H TI Hippocampal and cortical atrophy predict dementia in subcortical ischemic vascular disease SO NEUROLOGY LA English DT Article ID WHITE-MATTER LESIONS; ALZHEIMERS-DISEASE; MULTIINFARCT DEMENTIA; LACUNAR INFARCTION; BINSWANGER TYPE; MRI; BRAIN; REGISTRATION; CONSORTIUM; DIAGNOSIS AB Background: The cause of dementia in subcortical ischemic vascular disease (SIVD) is controversial. Objectives: To determine whether cognitive impairment in SIVD 1) correlates with measures of ischemic brain injury or brain atrophy, and/or 2) is due to concomitant AD. Methods: Volumetric MRI of the brain was performed in 1) elderly subjects with lacunes (L) and a spectrum of cognitive impairment-normal cognition (NC+L, n = 32), mild cognitive impairment (CI+L, n = 26), and dementia (D+L, n = 29); 2) a comparison group with probable AD (n = 28); and 3) a control group with normal cognition and no lacunes (NC). The authors examined the relationship between the severity of cognitive impairment and 1) volume, number, and location of lacunes; 2) volume of white matter signal hyperintensities (WMSH); and 3) measures of brain atrophy (i.e., hippocampal, cortical gray matter, and CSF volumes). Results: Among the three lacune groups, severity of cognitive impairment correlated with atrophy of the hippocampus and cortical gray matter, but not with any lacune measure. Although hippocampal atrophy was the best predictor of severity of cognitive impairment, there was evidence for a second, partially independent, atrophic process associated with ventricular dilation, cortical gray matter atrophy, and increase in WMSH. Eight autopsied SIVD cases showed variable severity of ischemic and neurofibrillary degeneration in the hippocampus, but no significant AD pathology in neocortex. The probable AD group gave evidence of only one atrophic process, reflected in the severity of hippocampal atrophy, Comparison of regional neocortical gray matter volumes showed sparing of the primary motor and visual cortices in the probable AD group, but relatively uniform atrophy in the D+L group. Conclusions: Dementia in SIVD, as in AD, correlates best with hippocampal and cortical atrophy, rather than any measure of lacunes. In SIVD, unlike AD, there is evidence for partial independence between these two atrophic processes. Hippocampal atrophy may result from a mixture of ischemic and degenerative pathologies. The cause of diffuse cortical atrophy is not known, but may be partially indexed by the severity of WMSH. C1 Neurobehav Res Inc, San Francisco, CA USA. Dept Vet Affairs Med Ctr, Magnet Resonance Unit, San Francisco, CA USA. Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Psychiat, San Francisco, CA 94143 USA. Univ Calif Davis, Dept Neurol, Davis, CA 95616 USA. Univ So Calif, Dept Neurol, Los Angeles, CA 90033 USA. Univ Calif Davis, Lawrence Berkeley Lab, Dept Neurol, Davis, CA 95616 USA. Univ Calif Davis, Ctr Funct Imaging, Davis, CA 95616 USA. RP Chui, H (reprint author), Geriatr Neurobehav & Alzheimer Ctr, 800 Annex W,7601 E Imperial Highway, Downey, CA 90242 USA. EM chui@hsc.usc.edu FU NIA NIH HHS [P01 AG012435-06A19001, P01 AG012435, P01 AG012435-06A10002, P01-AG12435, P30 AG010129, P30 AG010129-079001, P50-AG10129, R01 AG010897, R01 AG010897-14, R01-AG10897]; NIDA NIH HHS [F32 DA005683] NR 46 TC 265 Z9 288 U1 1 U2 11 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0028-3878 J9 NEUROLOGY JI Neurology PD DEC 12 PY 2000 VL 55 IS 11 BP 1626 EP 1635 PG 10 WC Clinical Neurology SC Neurosciences & Neurology GA 381NY UT WOS:000165770600007 PM 11113215 ER PT J AU Lobad, AI Averitt, RD Kwon, C Taylor, AJ AF Lobad, AI Averitt, RD Kwon, C Taylor, AJ TI Spin-lattice interaction in colossal magnetoresistance manganites SO APPLIED PHYSICS LETTERS LA English DT Article ID DOUBLE-EXCHANGE; SINGLE-CRYSTAL; LA0.7CA0.3MNO3; RELAXATION; ND0.7SR0.3MNO3; LOCALIZATION; LA1-XSRXMNO3; FERROMAGNET; PEROVSKITES; FILMS AB The metal-insulator transition and underlying spin dynamics in La0.7D0.3MnO3 (D=Ca, Sr) are investigated using optical pump-probe spectroscopy at 1.5 eV. Our measurements, which span the ferromagnetic-paramagnetic transition temperature, reveal that the dynamics of the optically induced spectral weight transfer follow the temperature dependence of the magnetic specific heat. This dependence reflects the intrinsic interdependence between the optical conductivity and magnetism in the manganites allowing for the determination of the spin-lattice coupling magnitude. (C) 2000 American Institute of Physics. [S0003-6951(00)04748-3]. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Taylor, AJ (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, MS K764, Los Alamos, NM 87545 USA. EM ttaylor@lanl.gov RI Kwon, Chuhee/A-8687-2008 NR 31 TC 45 Z9 46 U1 6 U2 21 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 11 PY 2000 VL 77 IS 24 BP 4025 EP 4027 AR PII [S0003-6951(00)04748-3] DI 10.1063/1.1329324 PG 3 WC Physics, Applied SC Physics GA 380FW UT WOS:000165690400049 ER PT J AU Gildemeister, JM Lee, AT Richards, PL AF Gildemeister, JM Lee, AT Richards, PL TI Monolithic arrays of absorber-coupled voltage-biased superconducting bolometers SO APPLIED PHYSICS LETTERS LA English DT Article ID STRONG ELECTROTHERMAL FEEDBACK AB We describe a design for bolometric detectors of infrared and mm-wave radiation produced in large-format filled arrays by standard planar lithography. A square grid of metallized silicon nitride absorbs the radiation. The bolometer suspension, sensor, and wiring occupy a small fraction of the area. We have produced a 1024 element array of fully released and suspended 1.5 mm x 1.5 mm bolometer micromeshes with a filling factor of 88%. We describe a voltage-biased superconducting bolometer built as a prototype for one array element. We have measured noise equivalent power = 2.3 x 10(-17) W/root Hz, tau = 24 ms, and G = 2.7 x 10(-11) W/K at 304 mK. (C) 2000 American Institute of Physics. [S0003-6951(00)00947-5]. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Lee, AT (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM atl@cfpa.berkeley.edu NR 11 TC 34 Z9 35 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 11 PY 2000 VL 77 IS 24 BP 4040 EP 4042 AR PII [S0003-6951(00)00947-5] DI 10.1063/1.1326844 PG 3 WC Physics, Applied SC Physics GA 380FW UT WOS:000165690400054 ER PT J AU Thundat, T Finot, E Hu, Z Ritchie, RH Wu, G Majumdar, A AF Thundat, T Finot, E Hu, Z Ritchie, RH Wu, G Majumdar, A TI Chemical sensing in Fourier space SO APPLIED PHYSICS LETTERS LA English DT Article ID RESONATING MICROCANTILEVERS; CANTILEVERS; SENSOR AB Chemical sensing using optical diffraction from an array of microcantilevers is demonstrated. Properly fashioned arrays of micromachined silicon-nitride cantilevers containing embedded deformable diffraction gratings are functionalized with chemically selective coatings. Adsorption of specific molecules on the cantilever leads to bending, which changes the diffraction pattern of a laser beam reflecting off the array. Quantitative chemical information can be obtained by monitoring the displacement of diffraction peaks as a function of analyte exposure. (C) 2000 American Institute of Physics. [S0003-6951(00)00251-5]. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Thundat, T (reprint author), Oak Ridge Natl Lab, Div Life Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Hu, Zhiyu/J-7742-2013 NR 19 TC 35 Z9 35 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD DEC 11 PY 2000 VL 77 IS 24 BP 4061 EP 4063 DI 10.1063/1.1332402 PG 3 WC Physics, Applied SC Physics GA 380FW UT WOS:000165690400061 ER PT J AU Csanyi, G Engeness, TD Ismail-Beigi, S Arias, TA AF Csanyi, G Engeness, TD Ismail-Beigi, S Arias, TA TI New physics of the 30 degrees partial dislocation in silicon revealed through ab initio calculation SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article; Proceedings Paper CT Conference on Extended Defects in Semiconductors 2000 CY JUL 18-22, 2000 CL UNIV SUSSEX, BRIGHTON, ENGLAND SP European Sci Fdn HO UNIV SUSSEX ID 90-DEGREES PARTIAL DISLOCATION; MOLECULAR-DYNAMICS; DEFORMED SILICON; ENERGY; DEFECTS; MOBILITY; MODELS; CORE AB On the basis of ab initio calculation, we propose a new structure for the fundamental excitation of the reconstructed 30 degrees partial dislocation in silicon. This soliton has a rare structure involving a fivefold-coordinated atom near the dislocation core. The unique electronic structure of this defect is consistent with the electron spin-resonance signature of the hitherto enigmatic thermally stable R centre of plastically deformed silicon. We present the first ab initio determination of the free energy of the soliton, which is also in agreement with the experimental observation. This identification suggests the possibility of an experimental determination of the density of solitons, a key defect in understanding the plastic flow of the material. C1 MIT, Dept Phys, Cambridge, MA 02139 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Cornell Univ, Atom & Solid State Phys Lab, Ithaca, NY 14853 USA. RP Csanyi, G (reprint author), MIT, Dept Phys, Cambridge, MA 02139 USA. RI Ismail-Beigi, Sohrab/F-2382-2014 OI Ismail-Beigi, Sohrab/0000-0002-7331-9624 NR 32 TC 5 Z9 5 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD DEC 11 PY 2000 VL 12 IS 49 BP 10029 EP 10037 DI 10.1088/0953-8984/12/49/302 PG 9 WC Physics, Condensed Matter SC Physics GA 386BC UT WOS:000166039400003 ER PT J AU Chien, CY Cho, HS Huang, W Li, Z Liang, GW Xie, XB AF Chien, CY Cho, HS Huang, W Li, Z Liang, GW Xie, XB TI New designs of CMS silicon pixel detectors for radiation hardness SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE CMS; pixel detector; silicon pixel detector; radiation damage; radiation hardness ID CHARGES N-EFF; DEFECT EVOLUTION; IRRADIATION AB New designs of silicon pixel detectors with n(+)/n/p(+) and double-sided multiguard ring structures have been developed for more radiation-tolerant CMS forward pixel sensors. In a later design modification, guard rings on the n(+) side are replaced with a single wide (640 mum) n(+) implant, and the entire n(+) side and the edge region of the p(+) side are grounded. All designs were fabricated from both normal and oxygen-enriched silicon wafers, and radiation hardness effects for neutron (1 MeV equivalent) and proton (24 GeV) irradiation of these detectors were compared. Other electrical characteristics such as leakage current, potential distribution over guard rings and full depletion voltage were tested, using standard techniques of I-V, V-V, C-V and TCT before and after irradiation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Brookhaven Natl Lab, Instrumentat Div, Upton, NY 11973 USA. RP Cho, HS (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 17 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 11 PY 2000 VL 455 IS 3 BP 564 EP 575 DI 10.1016/S0168-9002(00)00572-6 PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 386YG UT WOS:000166092800007 ER PT J AU Tanaka, Y Hara, H Ebisu, K Hibino, M Kametani, S Kikuchi, J Wintenberg, AL Walker, JW Franck, S Moscone, C Jones, JP Young, GR Matsumoto, T Sakaguchi, T Oyama, K Hamagaki, H AF Tanaka, Y Hara, H Ebisu, K Hibino, M Kametani, S Kikuchi, J Wintenberg, AL Walker, JW Franck, S Moscone, C Jones, JP Young, GR Matsumoto, T Sakaguchi, T Oyama, K Hamagaki, H TI Front-end readout system for PHENIX RICH SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE electronics; RICH; CPLD; backplane; source-synchronous ID DETECTOR AB A front-end readout system with a custom backplane and custom circuit modules has been developed for the RICH subsystem of the PHENIX experiment. The design specifications and test results of the backplane and the modules are presented in this paper. In the module design, flexibility for modification is maximized through the use of Complex Programmable Logic Devices. In the backplane design, a source-synchronous bus architecture is adopted for the data and control bus. The transfer speed of the backplane has reached 640 Mbyte/s with a 128-bit data bus. Total transaction time is estimated to be less than 30 mus per event when this system is used in the experiment. This result indicates that the performance satisfies the data-rate requirement of the PHENIX experiment. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Nagasaki Inst Appl Sci, Nagasaki 8510193, Japan. Waseda Univ, Shinjuku Ku, Tokyo 1698555, Japan. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Tokyo, Sch Sci, CNS, Tokyo 1130033, Japan. RP Tanaka, Y (reprint author), Nagasaki Inst Appl Sci, 536 Aba Machi, Nagasaki 8510193, Japan. RI HAMAGAKI, HIDEKI/G-4899-2014 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 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 11 PY 2000 VL 455 IS 3 BP 576 EP 588 DI 10.1016/S0168-9002(00)00529-5 PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 386YG UT WOS:000166092800008 ER PT J AU Fletcher, KA Geist, WH Brune, CR Fisher, BM Fitzgerald, RP Karwowski, HJ Kruse, DE Leonard, DS Ludwig, EJ Runkle, RC Veal, KD Wood, MH AF Fletcher, KA Geist, WH Brune, CR Fisher, BM Fitzgerald, RP Karwowski, HJ Kruse, DE Leonard, DS Ludwig, EJ Runkle, RC Veal, KD Wood, MH TI A proton polarimeter for He-3(d,p)He-4 polarization transfer studies SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE polarization transfer; proton polarimeter; He-3(d,p)He-4 ID SCATTERING AB A compact polarimeter has been constructed and calibrated to measure the polarization of 13-16 MeV protons, such as those emitted from the He-3(d,p)He-4 reaction near the E-d = 430 keV resonance. The polarimeter uses p-He-4 elastic scattering as an analyzer. It consists of a He-4 gas cell pressurized to 2.76 MPa and a left-right pair of CsI detectors collimated at 65 degrees to maximize the figure of merit for the device. The effective analyzing power and efficiency of the polarimeter have been measured as a function of energy using a collimated polarized proton beam. These measured values are in good agreement with a Monte Carlo computer simulation that forms the basis for the calibration curve for the device. Preliminary results from the He-3(d,p)He-4 reaction with polarized deuterons confirm that the proton polarimeter can be used to determine polarization transfer coefficients near the low-energy resonance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 SUNY Geneseo, Dept Phys & Astron, Geneseo, NY 14454 USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Triangle Univ, Nucl Lab, Durham, NC 27088 USA. Univ Calif Los Alamos Natl Lab, Grp NIS 5, Los Alamos, NM 87545 USA. Univ Virginia, Charlottesville, VA 22908 USA. RP Fletcher, KA (reprint author), SUNY Geneseo, Dept Phys & Astron, Geneseo, NY 14454 USA. RI Fitzgerald, Ryan/H-6132-2016 NR 16 TC 2 Z9 2 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 11 PY 2000 VL 455 IS 3 BP 620 EP 624 DI 10.1016/S0168-9002(00)00569-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 386YG UT WOS:000166092800013 ER PT J AU Beddingfield, DH Johnson, NH Menlove, HO AF Beddingfield, DH Johnson, NH Menlove, HO TI He-3 neutron proportional counter performance in high gamma-ray dose environments SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE neutron detector; gamma-ray sensitivity; He-3 AB We have studied the properties of He-3 neutron proportional tubes in gamma-ray environments to accommodate particular programmatic needs. In this paper, we summarize our results and experience to date into a single resource. Over the course of this study we have extended the operation of He-3 tubes from a maximum gamma-ray dose of a few Rad/h per active foot to beyond 200 Rad/h per active foot (30.5 cm). We have quantified the gamma-ray pileup in a variety of tube designs in a manner useful to system users and designers. We have developed a new hybrid He-3 tube that is suitable for prolonged high-dose exposure to gamma rays. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, Los Alamos, NM 87545 USA. GE Reuter Stokes Inc, Twinsburg, OH 44087 USA. RP Beddingfield, DH (reprint author), Univ Calif Los Alamos Natl Lab, Nonproliferat & Int Secur Div, MS E540, Los Alamos, NM 87545 USA. NR 6 TC 10 Z9 11 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD DEC 11 PY 2000 VL 455 IS 3 BP 670 EP 682 DI 10.1016/S0168-9002(00)00532-5 PG 13 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 386YG UT WOS:000166092800019 ER PT J AU Zhang, CG Guzei, IA Espenson, JH AF Zhang, CG Guzei, IA Espenson, JH TI Acidic C-H activation of methyltrioxorhenium (VII): Isolation and characterization of two compounds having the novel group C5H5N-CH2-ReO2 coordinated to tin(IV) SO ORGANOMETALLICS LA English DT Article ID TRANSITION-METALS; COMPLEXES; DERIVATIVES; HYDROLYSIS; CATALYSTS; LIGANDS AB Pyridine acts as a nucleophile toward the methylene group of the tautomer of CH3ReO3, CH2=Re(O)(2)OH. The structures of two complexes, [{C5H5-NCH2-Re(NC5H5)(3)(O)(2)}(2)](SnMe2Cl2)(ReO4)(2) and [{3-CH3C5H4NCH2-Re(NC5H4-3-Cl)(3)(O)(2)}(2)](SnMe2Cl2)-(ReO4)(2). 2CHCl(3), prepared by the reaction of pyridine with CH3ReO3 in, the presence of SnMe2Cl2, were confirmed by NMR and X-ray determinations. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 17 TC 9 Z9 9 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD DEC 11 PY 2000 VL 19 IS 25 BP 5257 EP 5259 DI 10.1021/om000683r PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 380MA UT WOS:000165704600003 ER PT J AU Dong, SJ Lee, FX Liu, KF Zhang, JB AF Dong, SJ Lee, FX Liu, KF Zhang, JB TI Chiral symmetry, quark mass, and scaling of the overlap fermions SO PHYSICAL REVIEW LETTERS LA English DT Article ID DIRAC OPERATOR; GAUGE-THEORIES; TOPOLOGICAL CHARGE; QUENCHED QCD; LATTICE QCD; CONDENSATE AB The chiral symmetry relation and scaling of the overlap fermions are studied numerically on the quenched lattices at 3 couplings with about the same physical volume. We find that the generalized Gell-Mann-Oakes-Renner relation is satisfied to better than 1% down to the smallest quark mass at m(0)a = 0.006. We also obtain the quark mass from the PCAC relation and the pseudoscalar masses. The renormalization group invariant quark mass is shown to be fairly independent of scale. The pi and p masses at a fixed m(pi)/m(rho) ratio indicate small O(a(2)) corrections. It is found that the critical slowing down sets in abruptly at a very small quark mass close to those of the physical it and d quarks. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. George Washington Univ, Dept Phys, Ctr Nucl Studies, Washington, DC 20052 USA. Jefferson Lab, Newport News, VA 23606 USA. Zhejiang Univ, Zhejiang Inst Modern Phys, Hangzhou 310027, Peoples R China. RP Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. NR 28 TC 51 Z9 51 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 11 PY 2000 VL 85 IS 24 BP 5051 EP 5054 DI 10.1103/PhysRevLett.85.5051 PG 4 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000010 ER PT J AU Abe, K Abe, K Abe, T Adam, I Akimoto, H Aston, D Baird, KG Baltay, C Band, HR Barklow, TL Bauer, JM Bellodi, G Berger, R Blaylock, G Bogart, JR Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Calcaterra, A Cassell, R Chou, A Cohn, HO Coller, JA Convery, MR Cook, V Cowan, RF Crawford, G Damerell, CJS Daoudi, M de Groot, N de Sangro, R Dong, DN Doser, M Dubois, R Erofeeva, I Eschenburg, V Etzion, E Fahey, S Falciai, D Fernandez, JP Flood, K Frey, R Hart, EL Hasuko, K Hertzbach, SS Huffer, ME Huynh, X Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Kajikawa, R Kalelkar, M Kang, HJ Kofler, RR Kroeger, RS Langston, M Leith, DWG Lia, V Lin, C Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T McKemey, AK Messner, R Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Narita, S Nauenberg, U Neal, H Nesom, G Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, CH Peruzzi, I Piccolo, M Piemontese, L Plano, RJ Prepost, R Prescott, CY Ratcliff, BN Reidy, J Reinertsen, PL Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schumm, BA Schwiening, J Serbo, VV Shapiro, G Sinev, NB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, H Su, D Suekane, F Sugiyama, A Suzuki, A Swartz, M Taylor, FE Thom, J Torrence, E Usher, T Va'vra, J Verdier, R Wagner, DL Waite, AP Walston, S Weidemann, AW Weiss, ER Whitaker, JS Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, M Wright, TR Yamamoto, RK Yashima, J Yellin, SJ Young, CC Yuta, H AF Abe, K Abe, K Abe, T Adam, I Akimoto, H Aston, D Baird, KG Baltay, C Band, HR Barklow, TL Bauer, JM Bellodi, G Berger, R Blaylock, G Bogart, JR Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Calcaterra, A Cassell, R Chou, A Cohn, HO Coller, JA Convery, MR Cook, V Cowan, RF Crawford, G Damerell, CJS Daoudi, M de Groot, N de Sangro, R Dong, DN Doser, M Dubois, R Erofeeva, I Eschenburg, V Etzion, E Fahey, S Falciai, D Fernandez, JP Flood, K Frey, R Hart, EL Hasuko, K Hertzbach, SS Huffer, ME Huynh, X Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Kajikawa, R Kalelkar, M Kang, HJ Kofler, RR Kroeger, RS Langston, M Leith, DWG Lia, V Lin, C Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T McKemey, AK Messner, R Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Narita, S Nauenberg, U Neal, H Nesom, G Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, CH Peruzzi, I Piccolo, M Piemontese, L Plano, RJ Prepost, R Prescott, CY Ratcliff, BN Reidy, J Reinertsen, PL Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schumm, BA Schwiening, J Serbo, VV Shapiro, G Sinev, NB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, H Su, D Suekane, F Sugiyama, A Suzuki, A Swartz, M Taylor, FE Thom, J Torrence, E Usher, T Va'vra, J Verdier, R Wagner, DL Waite, AP Walston, S Weidemann, AW Weiss, ER Whitaker, JS Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, M Wright, TR Yamamoto, RK Yashima, J Yellin, SJ Young, CC Yuta, H CA SLD Collaboration TI First direct measurement of the parity-violating coupling of the Z(0) to the s quark SO PHYSICAL REVIEW LETTERS LA English DT Article ID SLD; DETECTOR; TAG AB We present the first direct measurement of A,, the parity-violating coupling of the Z(0) boson to the strange quark. using similar to 550000 e(+)e(-) --> Z(0) --> hadrons events recorded by the SLC Large Detector with a polarized e(-) beam. We tagged Z(0) --> s (s) over bar events by the absence of B or D hadrons and the presence in each hemisphere of a high momentum K(+/-) or K(s)(0). Fitting the polar angle distributions of the strangeness-signed thrust axis gave A(s) = 0.895 +/- 0.066(stat) +/- 0.062(syst). The analyzing power and u (u) over bar + d (d) over bar background were constrained using the data, greatly reducing any model dependence. C1 Univ Bristol, Bristol BS8 1TH, Avon, England. Brunel Univ, Uxbridge UB8 3PH, Middx, England. Boston Univ, Boston, MA 02215 USA. Univ Colorado, Boulder, CO 80309 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Univ Ferrara, Ist Nazl Fis Nucl, Nazl Frascati Lab, I-44100 Ferrara, Italy. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Mississippi, University, MS 38677 USA. MIT, Cambridge, MA 02139 USA. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow 119899, Russia. Nagoya Univ, Chikusa Ku, Nagoya, Aichi 464, Japan. Univ Oregon, Eugene, OR 97403 USA. Univ Oxford, Oxford OX1 3RH, England. Rutgers State Univ, Piscataway, NJ 08855 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Soongsil Univ, Seoul 156743, South Korea. Univ Tennessee, Knoxville, TN 37996 USA. Tohoku Univ, Sendai, Miyagi 980, Japan. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Univ Washington, Seattle, WA 98105 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06511 USA. RI de Groot, Nicolo/A-2675-2009; Stahl, Achim/E-8846-2011; de Sangro, Riccardo/J-2901-2012; Calcaterra, Alessandro/P-5260-2015; Frey, Raymond/E-2830-2016; OI Stahl, Achim/0000-0002-8369-7506; de Sangro, Riccardo/0000-0002-3808-5455; Calcaterra, Alessandro/0000-0003-2670-4826; Frey, Raymond/0000-0003-0341-2636; Wilson, Robert/0000-0002-8184-4103 NR 24 TC 13 Z9 13 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 11 PY 2000 VL 85 IS 24 BP 5059 EP 5063 DI 10.1103/PhysRevLett.85.5059 PG 5 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000012 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adams, DL Adams, M Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Balm, PW Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Bassler, U Bean, A Begel, M Belyaev, A Beri, SB Bernardi, G Bertram, I Besson, A Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Blazey, G Blessing, S Boehnlein, A Bojko, NI Borcherding, F Brandt, A Breedon, R Briskin, G Brock, R Brooijmans, G Bross, A Buchholz, D Buehler, M Buescher, V Burtovoi, VS Butler, JM Canelli, F Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chan, KM Chekulaev, SV Cho, DK Choi, S Chopra, S Christenson, JH Chung, M Claes, D Clark, AR Cochran, J Coney, L Connolly, B Cooper, WE Coppage, D Cummings, MAC Cutts, D Dahl, OI Davis, GA Davis, K De, K Del Signore, K Demarteau, M Demina, R Demine, P Denisov, D Denisov, SP Desai, S Diehl, HT Diesburg, M Di Loreto, G Doulas, S Draper, P Ducros, Y Dudko, LV Duensing, S Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Estrada, J Evans, H Evdokimov, VN Fahland, T Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Fleuret, F Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gilmartin, R Ginther, G Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Graham, G Grannis, PD Green, JA Greenlee, H Grinstein, S Groer, L Grudberg, P Grunendahl, S Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hays, C Hebert, C Hedin, D Heinson, AP Heintz, U Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hou, S Huang, Y Ito, AS Jerger, SA Jesik, R Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Juste, A Kahn, S Kajfasz, E Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Knuteson, B Ko, W Kohli, JM Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kubantsev, M Kuleshov, S Kulik, Y Kunori, S Kuznetsov, VE Landsberg, G Leflat, A Lehner, F Li, J Li, QZ Lima, JGR Lincoln, D Linn, S Linnemann, J Lipton, R Lucotte, A Lueking, L Lundstedt, C Maciel, AKA Madaras, RJ Manankov, V Mao, HS Marshall, T Martin, MI Martin, RD Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McMahon, T Melanson, HL Meng, XC Merkin, M Merritt, KW Miao, C Miettinen, H Mihalcea, D Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Moore, RW Mostafa, M da Motta, H Nagy, E Nang, F Narain, M Narasimham, VS Neal, HA Negret, JP Negroni, S Norman, D Oesch, L Oguri, V Olivier, B Oshima, N Padley, P Pan, LJ Para, A Parashar, N Partridge, R Parua, N Paterno, M Patwa, A Pawlik, B Perkins, J Peters, M Peters, O Piegaia, R Piekarz, H Pope, BG Popkov, E Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramberg, E Rapidis, PA Reay, NW Reucroft, S Rha, J Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Santoro, A Sawyer, L Schamberger, RD Schellman, H Schwartzman, A Sculli, J Sen, N Shabalina, E Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Sidwell, RA Simak, V Singh, H Singh, JB Sirotenko, V Slattery, P Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sorin, V Sosebee, M Sotnikova, N Soustruznik, K Souza, M Stanton, NR Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Stutte, L Sznajder, A Taylor, W Tentindo-Repond, S Thompson, J Toback, D Tripathi, SM Trippe, TG Turcot, AS Tuts, PM van Gemmeren, P Vaniev, V Van Kooten, R Varelas, N Volkov, AA Vorobiev, AP Wahl, HD Wang, H Wang, ZM Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Whiteson, D Wightman, JA Wijngaarden, DA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Wood, DR Yamada, R Yamin, P Yasuda, T Yip, K Youssef, S Yu, J Yu, Z Zanabria, M Zheng, H Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zutshi, V Zverev, EG Zylberstejn, A AF Abbott, B Abolins, M Abramov, V Acharya, BS Adams, DL Adams, M Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Balm, PW Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Bassler, U Bean, A Begel, M Belyaev, A Beri, SB Bernardi, G Bertram, I Besson, A Bezzubov, VA Bhat, PC Bhatnagar, V Bhattacharjee, M Blazey, G Blessing, S Boehnlein, A Bojko, NI Borcherding, F Brandt, A Breedon, R Briskin, G Brock, R Brooijmans, G Bross, A Buchholz, D Buehler, M Buescher, V Burtovoi, VS Butler, JM Canelli, F Carvalho, W Casey, D Casilum, Z Castilla-Valdez, H Chakraborty, D Chan, KM Chekulaev, SV Cho, DK Choi, S Chopra, S Christenson, JH Chung, M Claes, D Clark, AR Cochran, J Coney, L Connolly, B Cooper, WE Coppage, D Cummings, MAC Cutts, D Dahl, OI Davis, GA Davis, K De, K Del Signore, K Demarteau, M Demina, R Demine, P Denisov, D Denisov, SP Desai, S Diehl, HT Diesburg, M Di Loreto, G Doulas, S Draper, P Ducros, Y Dudko, LV Duensing, S Dugad, SR Dyshkant, A Edmunds, D Ellison, J Elvira, VD Engelmann, R Eno, S Eppley, G Ermolov, P Eroshin, OV Estrada, J Evans, H Evdokimov, VN Fahland, T Feher, S Fein, D Ferbel, T Fisk, HE Fisyak, Y Flattum, E Fleuret, F Fortner, M Frame, KC Fuess, S Gallas, E Galyaev, AN Gartung, P Gavrilov, V Genik, RJ Genser, K Gerber, CE Gershtein, Y Gibbard, B Gilmartin, R Ginther, G Gomez, B Gomez, G Goncharov, PI Solis, JLG Gordon, H Goss, LT Gounder, K Goussiou, A Graf, N Graham, G Grannis, PD Green, JA Greenlee, H Grinstein, S Groer, L Grudberg, P Grunendahl, S Gupta, A Gurzhiev, SN Gutierrez, G Gutierrez, P Hadley, NJ Haggerty, H Hagopian, S Hagopian, V Hahn, KS Hall, RE Hanlet, P Hansen, S Hauptman, JM Hays, C Hebert, C Hedin, D Heinson, AP Heintz, U Heuring, T Hirosky, R Hobbs, JD Hoeneisen, B Hoftun, JS Hou, S Huang, Y Ito, AS Jerger, SA Jesik, R Johns, K Johnson, M Jonckheere, A Jones, M Jostlein, H Juste, A Kahn, S Kajfasz, E Karmanov, D Karmgard, D Kehoe, R Kim, SK Klima, B Klopfenstein, C Knuteson, B Ko, W Kohli, JM Kostritskiy, AV Kotcher, J Kotwal, AV Kozelov, AV Kozlovsky, EA Krane, J Krishnaswamy, MR Krzywdzinski, S Kubantsev, M Kuleshov, S Kulik, Y Kunori, S Kuznetsov, VE Landsberg, G Leflat, A Lehner, F Li, J Li, QZ Lima, JGR Lincoln, D Linn, S Linnemann, J Lipton, R Lucotte, A Lueking, L Lundstedt, C Maciel, AKA Madaras, RJ Manankov, V Mao, HS Marshall, T Martin, MI Martin, RD Mauritz, KM May, B Mayorov, AA McCarthy, R McDonald, J McMahon, T Melanson, HL Meng, XC Merkin, M Merritt, KW Miao, C Miettinen, H Mihalcea, D Mincer, A Mishra, CS Mokhov, N Mondal, NK Montgomery, HE Moore, RW Mostafa, M da Motta, H Nagy, E Nang, F Narain, M Narasimham, VS Neal, HA Negret, JP Negroni, S Norman, D Oesch, L Oguri, V Olivier, B Oshima, N Padley, P Pan, LJ Para, A Parashar, N Partridge, R Parua, N Paterno, M Patwa, A Pawlik, B Perkins, J Peters, M Peters, O Piegaia, R Piekarz, H Pope, BG Popkov, E Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Ramberg, E Rapidis, PA Reay, NW Reucroft, S Rha, J Rijssenbeek, M Rockwell, T Roco, M Rubinov, P Ruchti, R Rutherfoord, J Santoro, A Sawyer, L Schamberger, RD Schellman, H Schwartzman, A Sculli, J Sen, N Shabalina, E Shankar, HC Shivpuri, RK Shpakov, D Shupe, M Sidwell, RA Simak, V Singh, H Singh, JB Sirotenko, V Slattery, P Smith, E Smith, RP Snihur, R Snow, GR Snow, J Snyder, S Solomon, J Sorin, V Sosebee, M Sotnikova, N Soustruznik, K Souza, M Stanton, NR Steinbruck, G Stephens, RW Stevenson, ML Stichelbaut, F Stoker, D Stolin, V Stoyanova, DA Strauss, M Streets, K Strovink, M Stutte, L Sznajder, A Taylor, W Tentindo-Repond, S Thompson, J Toback, D Tripathi, SM Trippe, TG Turcot, AS Tuts, PM van Gemmeren, P Vaniev, V Van Kooten, R Varelas, N Volkov, AA Vorobiev, AP Wahl, HD Wang, H Wang, ZM Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Whiteson, D Wightman, JA Wijngaarden, DA Willis, S Wimpenny, SJ Wirjawan, JVD Womersley, J Wood, DR Yamada, R Yamin, P Yasuda, T Yip, K Youssef, S Yu, J Yu, Z Zanabria, M Zheng, H Zhou, Z Zhu, ZH Zielinski, M Zieminska, D Zieminski, A Zutshi, V Zverev, EG Zylberstejn, A CA D0 Collaboration TI Cross section for b-jet production in (p)over-barp collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY QUARK PRODUCTION; P(P)OVER-BAR COLLISIONS; HADRONIC COLLISIONS; E+E ANNIHILATION; QCD AB Bottom-quark production in (p) over barp collisions at roots = 1.8 TeV is studied with 5 pb(-1) of data collected in 1995 by the DO detector at the Fermilab Tevatron Collider The differential production cross section for b jets in the central rapidity region (\y(b)\ < 1) as a function of jet transverse energy is extracted from a muon-tagged jet sample. Within experimental and theoretical uncertainties, DO results are found to be higher than, but compatible with, next-to-leading-order QCD predictions. C1 Univ Buenos Aires, RA-1053 Buenos Aires, DF, Argentina. Ctr Brasileiro Pesquisas Fis, LAFEX, Rio De Janeiro, Brazil. Univ Estado Rio de Janeiro, Rio De Janeiro, Brazil. Inst High Energy Phys, Beijing 100039, Peoples R China. Univ Los Andes, Bogota, Colombia. Charles Univ, Prague, Czech Republic. Univ San Francisco Quito, Quito, Ecuador. Univ Grenoble 1, CNRS, IN2P3, Inst Sci Nucl, F-38041 Grenoble, France. Univ Mediterranee, CNRS, IN2P3, CPPM, Marseille, France. Univ Paris 05, LPNHE, CNRS, IN2P3, Paris, France. Univ Paris 07, LPNHE, CNRS, IN2P3, Paris, France. CEA Saclay, Serv Phys Particules, DAPNIA, F-91191 Gif Sur Yvette, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi, India. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. NIKHEF H, FOM, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, NIKHEF H, Amsterdam, Netherlands. Inst Phys Nucl, Krakow, Poland. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Lancaster, Lancaster LA1 4YW, England. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. Calif State Univ Fresno, Fresno, CA 93740 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Florida State Univ, Tallahassee, FL 32306 USA. Univ Hawaii, Honolulu, HI 96822 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Chicago, IL 60607 USA. No Illinois Univ, De Kalb, IL 60115 USA. Northwestern Univ, Evanston, IL 60208 USA. Indiana Univ, Bloomington, IN 47405 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Kansas State Univ, Manhattan, KS 66506 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Maryland, College Pk, MD 20742 USA. Boston Univ, Boston, MA 02215 USA. Northeastern Univ, Boston, MA 02115 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Nebraska, Lincoln, NE 68588 USA. Columbia Univ, New York, NY 10027 USA. NYU, New York, NY 10003 USA. Univ Rochester, Rochester, NY 14627 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Langston Univ, Langston, OK 73050 USA. Univ Oklahoma, Norman, OK 73019 USA. Brown Univ, Providence, RI 02912 USA. Univ Texas, Arlington, TX 76019 USA. Texas A&M Univ, College Stn, TX 77843 USA. Rice Univ, Houston, TX 77005 USA. Univ Washington, Seattle, WA 98195 USA. RP Abbott, B (reprint author), Univ Buenos Aires, RA-1053 Buenos Aires, DF, Argentina. RI Sznajder, Andre/L-1621-2016; Canelli, Florencia/O-9693-2016; Belyaev, Alexander/F-6637-2015; Shivpuri, R K/A-5848-2010; Gutierrez, Phillip/C-1161-2011; Dudko, Lev/D-7127-2012; Leflat, Alexander/D-7284-2012; Kim, Sun Kee/G-2042-2015; Merkin, Mikhail/D-6809-2012; Yip, Kin/D-6860-2013; Kuleshov, Sergey/D-9940-2013; De, Kaushik/N-1953-2013; Oguri, Vitor/B-5403-2013; Alves, Gilvan/C-4007-2013; Chekulaev, Sergey/O-1145-2015 OI Sznajder, Andre/0000-0001-6998-1108; Canelli, Florencia/0000-0001-6361-2117; Belyaev, Alexander/0000-0002-1733-4408; Dudko, Lev/0000-0002-4462-3192; Kim, Sun Kee/0000-0002-0013-0775; Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; NR 28 TC 80 Z9 80 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 DEC 11 PY 2000 VL 85 IS 24 BP 5068 EP 5073 DI 10.1103/PhysRevLett.85.5068 PG 6 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000014 ER PT J AU Beiersdorfer, P Olson, RE Brown, GV Chen, H Harris, CL Neill, PA Schweikhard, L Utter, SB Widmann, K AF Beiersdorfer, P Olson, RE Brown, GV Chen, H Harris, CL Neill, PA Schweikhard, L Utter, SB Widmann, K TI X-ray emission following eow-energy charge exchange collisions of highly charged ions SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-CAPTURE COLLISIONS; MAGNETIC TRAPPING MODE; COMETS; SPECTROSCOPY; TRANSPORT; TOKAMAK; PLASMA; HEAVY; H-2 AB K-shell x-ray emission following low-energy charge exchange collisions (less than or equal to 11 eV/amu) has been measured for ten ban and hydrogenic ions up to U91+. The data resolve capture into angular momentum states with l = 1 and provide a stringent test of theory. The assumption of Stark mixing of angular momentum states is inappropriate at such energies. Results from detailed calculations give a better description of the data, but significant discrepancies are noted. The measurements show that the hardness ratio of charge-exchange induced K-shell x-ray emission represents a diagnostic of the dynamics of ion-atom interactions in situations where the energy is below 1 keV/amu, e.g,, in solar wind collisions. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. Univ Missouri, Dept Phys, Rolla, MO 65401 USA. Univ Nevada, Dept Phys, Reno, NV 89557 USA. Univ Mainz, Inst Phys, D-55099 Mainz, Germany. RP Beiersdorfer, P (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. NR 25 TC 74 Z9 75 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 DEC 11 PY 2000 VL 85 IS 24 BP 5090 EP 5093 DI 10.1103/PhysRevLett.85.5090 PG 4 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000019 ER PT J AU Cohen, SA Glasser, AH AF Cohen, SA Glasser, AH TI Ion heating in the field-reversed configuration by rotating magnetic fields near the ion-cyclotron resonance SO PHYSICAL REVIEW LETTERS LA English DT Article ID CURRENT DRIVE; STABILITY; PARTICLES; ELECTRONS; ROTAMAK; ORBITS AB The trajectories of ions confined in a field-reversed configuration (FRC) equilibrium magnetic geometry and heated with a small-amplitude, odd-parity rotating magnetic field (RMF) have been studied with a Hamiltonian computer code. When the RMF frequency is in the ion-cyclotron range, explosive heating occurs. Higher-energy ions are found to have betatron-type orbits, preferentially localized near the FRC's midplane. These results are relevant to a compact magnetic-fusion-reactor design. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Cohen, SA (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 27 TC 14 Z9 16 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 11 PY 2000 VL 85 IS 24 BP 5114 EP 5117 DI 10.1103/PhysRevLett.85.5114 PG 4 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000025 ER PT J AU Wu, LJ Zhu, YM Tafto, J AF Wu, LJ Zhu, YM Tafto, J TI Picometer accuracy in measuring lattice displacements across planar faults by interferometry in coherent electron diffraction SO PHYSICAL REVIEW LETTERS LA English DT Article ID CRYSTALS; BOUNDARIES; OXYGEN AB We calculate the shadow image in far field below a thin crystal when a coherent electron source is placed at micrometer distances above the specimen, and note that the presence of a planar fault results in very strong oscillatory contrast. We realize these predictions experimentally using a field-emission electron source in a microscope. With this technique, we determine displacement vectors at planar faults with an accuracy down to I pm in studies of the Bi2Sr2CaCu2O8 superconductor containing thin intercalated layers. C1 Brookhaven Natl Lab, Div Sci Mat, Upton, NY 11973 USA. RP Zhu, YM (reprint author), Brookhaven Natl Lab, Div Sci Mat, Upton, NY 11973 USA. NR 23 TC 20 Z9 22 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 DEC 11 PY 2000 VL 85 IS 24 BP 5126 EP 5129 DI 10.1103/PhysRevLett.85.5126 PG 4 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000028 ER PT J AU Yeh, V Berbil-Bautista, L Wang, CZ Ho, KM Tringides, MC AF Yeh, V Berbil-Bautista, L Wang, CZ Ho, KM Tringides, MC TI Role of the metal/semiconductor interface in quantum size effects: Pb/Si(111) SO PHYSICAL REVIEW LETTERS LA English DT Article ID HELIUM-ATOM SCATTERING; THIN METAL-FILMS; BY-LAYER GROWTH; PB; SURFACES; AG AB Self-organized islands of uniform heights can form at low temperatures on metal/semiconductor systems as a result of quantum size effects, i.e., the occupation of discrete electron energy levels in the film. We compare the growth mode on two different substrates [Si(111)-(7 X 7) vs Si(lll)-Pb(root3 X root3)] with spot profile analysis low-energy electron diffraction. For the same growth conditions (of coverage and temperature) 7-step islands are the most stable islands on the (7 X 7) phase, while 5-step (but larger islands)are the most stable islands on the (root3 X root3). A theoretical calculation suggests that the height selection on the two interfaces can be attributed to the amount of charge transfer at the interface. C1 Iowa State Univ, Dept Phys, Ames, IA 50011 USA. US DOE, Ames Lab, Ames, IA 50011 USA. RP Tringides, MC (reprint author), Iowa State Univ, Dept Phys, Ames, IA 50011 USA. NR 21 TC 123 Z9 125 U1 3 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 11 PY 2000 VL 85 IS 24 BP 5158 EP 5161 DI 10.1103/PhysRevLett.85.5158 PG 4 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000036 ER PT J AU Damascelli, A Lu, DH Shen, KM Armitage, NP Ronning, F Feng, DL Kim, C Shen, ZX Kimura, T Tokura, Y Mao, ZQ Maeno, Y AF Damascelli, A Lu, DH Shen, KM Armitage, NP Ronning, F Feng, DL Kim, C Shen, ZX Kimura, T Tokura, Y Mao, ZQ Maeno, Y TI Fermi surface, surface states, and surface reconstruction in Sr2RuO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCONDUCTOR SR2RUO4 AB The electronic structure of Sr2RuO4 is investigated by high angular resolution ARPES at several incident photon energies. We address the controversial issues of the Fermi surface (FS) topology and the van Hove singularity at the M point, showing that a surface state and the replica of the primary FS due to root2 X root2 surface reconstruction are responsible for previous conflicting interpretations. The FS thus determined by ARPES is consistent with the de Haas-van Alphen results, and it provides additional information on the detailed shape of the alpha, beta, and gamma sheets. C1 Stanford Univ, Dept Phys & Appl Phys, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Univ Tokyo, Dept Appl Phys, Tokyo 1138656, Japan. JRCAT, Tsukuba, Ibaraki 3050046, Japan. Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. JST, CREST, Kawagoe, Saitama 3320012, Japan. RP Damascelli, A (reprint author), Stanford Univ, Dept Phys & Appl Phys, Stanford, CA 94305 USA. RI Shen, Kyle/B-3693-2008; Tokura, Yoshinori/C-7352-2009; damascelli, andrea/P-6329-2014 OI damascelli, andrea/0000-0001-9895-2226 NR 14 TC 144 Z9 144 U1 3 U2 45 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 DEC 11 PY 2000 VL 85 IS 24 BP 5194 EP 5197 DI 10.1103/PhysRevLett.85.5194 PG 4 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000045 ER PT J AU Walti, C Ott, HR Fisk, Z Smith, JL AF Walti, C Ott, HR Fisk, Z Smith, JL TI Andreev reflection at point contacts with heavy-fermion UBe13? Walti et al. reply SO PHYSICAL REVIEW LETTERS LA English DT Letter C1 ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland. Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Walti, C (reprint author), ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland. NR 5 TC 7 Z9 7 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 11 PY 2000 VL 85 IS 24 BP 5258 EP 5258 DI 10.1103/PhysRevLett.85.5258 PG 1 WC Physics, Multidisciplinary SC Physics GA 382CC UT WOS:000165800000066 ER PT J AU Balbi, A Ade, P Bock, J Borrill, J Boscaleri, A De Bernardis, P Ferreira, PG Hanany, S Hristov, V Jaffe, AH Lee, AT Oh, S Pascale, E Rabii, B Richards, RL Smoot, GF Stompor, R Winant, CD Wu, JHP AF Balbi, A Ade, P Bock, J Borrill, J Boscaleri, A De Bernardis, P Ferreira, PG Hanany, S Hristov, V Jaffe, AH Lee, AT Oh, S Pascale, E Rabii, B Richards, RL Smoot, GF Stompor, R Winant, CD Wu, JHP TI Constraints on cosmological parameters from MAXIMA-1 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; large-scale structure of universe ID MICROWAVE BACKGROUND ANISOTROPIES; POWER SPECTRUM; DARK-MATTER; CONSTANT; SUPERNOVAE; UNIVERSE AB We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of l in the first flight of the MAXIMA balloon-borne experiment (MAXIMA-1) and the low-l results from the COBE Differential Microwave Radiometer experiment. We find constraints on the total energy density of the universe, Omega = 1.0(-0.30)(+0.15), the physical density of baryons, Omega (b)h(2) = 0.03 +/- 0.01, the physical density of cold dark matter, Omega (cdm)h(2) = 0.2(-0.1)(+0.2), and the spectral index of primordial scalar fluctuations, n(s) = 1.08 +/- 0.1, all at the 95% confidence level. By combining our results with measurements of high-redshift supernovae we constrain the value of the cosmological constant and the fractional amount of pressureless matter in the universe to 0.45 < (Lambda) < 0.75 and 0.25 < Omega (m) < 0.50, at the 95% confidence level. Our results are consistent with a hat universe and the shape parameter deduced from large-scale structure, and in marginal agreement with the baryon density from big bang nucleosynthesis. C1 Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. CNR, IROE, Florence, Italy. Univ Rome La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Univ Oxford, Dept Phys Astrophys Nucl & Astrophys, Oxford OX1 3RH, England. Inst Super Tecn, CENTRA, P-1094001 Lisbon, Portugal. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Nicholas Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Balbi, A (reprint author), Univ Roma Tor Vergata, Dipartimento Fis, Via Ric Sci 1, I-00133 Rome, Italy. RI Jaffe, Andrew/D-3526-2009 NR 28 TC 324 Z9 327 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2000 VL 545 IS 1 BP L1 EP L4 DI 10.1086/317323 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 388MP UT WOS:000166185100001 ER PT J AU Hanany, S Ade, P Balbi, A Bock, J Borrill, J Boscaleri, A De Bernardis, P Ferreira, PG Hristov, VV Jaffe, AH Lange, AE Lee, AT Mauskopf, PD Netterfield, CB Oh, S Pascale, E Rabii, B Richards, PL Smoot, GF Stompor, R Winant, CD Wu, JHP AF Hanany, S Ade, P Balbi, A Bock, J Borrill, J Boscaleri, A De Bernardis, P Ferreira, PG Hristov, VV Jaffe, AH Lange, AE Lee, AT Mauskopf, PD Netterfield, CB Oh, S Pascale, E Rabii, B Richards, PL Smoot, GF Stompor, R Winant, CD Wu, JHP TI MAXIMA-1: A measurement of the cosmic microwave background anisotropy on angular scales of 10 '-5 degrees SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID EMISSION; MAPS AB We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of the Millimeter-wave Anisotropy Experiment Imaging Array (MAXIMA). MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 deg(2) region of the sky with 10' resolution at frequencies of 150, 240, and 410 GHz. The data were calibrated using in-flight measurements of the CMB dipole anisotropy. A map of the CMB anisotropy was produced from three 150 and one 240 GHz photometer without need for foreground subtractions. Analysis of this CMB map yields a power spectrum for the CMB anisotropy over the range 36 less than or equal to l less than or equal to 785. The spectrum shows a peak with an amplitude of 78 +/- 6 muK at l similar or equal to 220 and an amplitude varying between similar to 40 and similar to 50 muK for 400 less than or similar to l less than or similar to 785. C1 Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. Lawrence Berkeley Natl Lab, Div Phys, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Phys, Pasadena, CA 91125 USA. Lawrence Berkeley Natl Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA 94720 USA. CNR, IROE, I-50127 Florence, Italy. Univ Rome La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Univ Oxford, Dept Astrophys, Oxford OX1 3RH, England. Inst Super Tecn, CENTRA, Lisbon, Portugal. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Wales, Dept Phys & Astron, Cardiff CF2 3YB, S Glam, Wales. Univ Toronto, Dept Phys & Astron, Toronto, ON M5S 1A1, Canada. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Hanany, S (reprint author), Univ Minnesota, Sch Phys & Astron, 116 Church St SE, Minneapolis, MN 55455 USA. RI Jaffe, Andrew/D-3526-2009 NR 28 TC 756 Z9 762 U1 4 U2 11 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 10 PY 2000 VL 545 IS 1 BP L5 EP L9 DI 10.1086/317322 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 388MP UT WOS:000166185100002 ER PT J AU Propp, RM Colella, P Crutchfield, WY Day, MS AF Propp, RM Colella, P Crutchfield, WY Day, MS TI A numerical model for trickle bed reactors SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE trickle bed reactor; conservation laws; porous media flows; Godunov methods ID HYPERBOLIC CONSERVATION-LAWS; RESERVOIR SIMULATION; MATHEMATICAL STRUCTURE; FLOW AB Trickle bed reactors are governed by equations of Row in porous media such as Darcy's law and the conservation of mass. Our numerical method for solving these equations is based on a total-velocity splitting, sequential formulation which leads to an implicit pressure equation and a semi-implicit mass conservation equation. We use high-resolution finite-difference methods to discretize these equations. Our solution scheme extends previous work in modeling porous media Rows in two ways. First, we incorporate physical effects due to capillary pressure, a nonlinear inlet boundary condition, spatial porosity variations, and inertial effects on phase mobilities. In particular, capillary forces introduce a parabolic component into the recast evolution equation, and the inertial effects give rise to hyperbolic nonconvexity. Second, we introduce a modification of the slope-limiting algorithm to prevent our numerical method from producing spurious shocks. We present a numerical algorithm for accommodating these difficulties, show the algorithm is second-order accurate, and demonstrate its performance on a number of simplified problems relevant to trickle bed reactor modeling. (C) 2000 Academic Press. C1 Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Propp, RM (reprint author), Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 30 TC 22 Z9 23 U1 1 U2 6 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD DEC 10 PY 2000 VL 165 IS 2 BP 311 EP 333 DI 10.1006/jcph.2000.6604 PG 23 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 393ZY UT WOS:000166500600001 ER PT J AU Vay, JL AF Vay, JL TI A new absorbing layer boundary condition for the wave equation SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE finite-difference; electromagnetic; wave equation; absorbing boundary condition; ABC; perfectly matched layer; PML; Berenger; Sommerfeld AB A new absorbing boundary condition using an absorbing layer is presented for application to finite-difference time-domain (FDTD) calculation of the wave equation. This algorithm is by construction a hybrid between the Berenger perfectly matched layer (PML) algorithm and the one-way Sommerfeld algorithm. The new prescription contains both of these earlier ones as particular cases, and retains benefits from both. Numerical results indicate that the new algorithm provides absorbing rates superior to those of the PML algorithm. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Accelerator & Fus Res, Berkeley, CA 94720 USA. RP Vay, JL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Accelerator & Fus Res, Berkeley, CA 94720 USA. NR 6 TC 10 Z9 10 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD DEC 10 PY 2000 VL 165 IS 2 BP 511 EP 521 DI 10.1006/jcph.2000.6623 PG 11 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 393ZY UT WOS:000166500600009 ER PT J AU Torres, DJ Brackbill, JU AF Torres, DJ Brackbill, JU TI The point-set method: Front-tracking without connectivity SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE front-tracking; connectivity; surface tension; parasitic currents ID DIRECT NUMERICAL SIMULATIONS; REYNOLDS-NUMBER ARRAYS; BUBBLY FLOWS; SURFACE-TENSION; FLUID-FLOWS; COMPUTATIONS; FORMULATION AB We describe a point-set method for extracting the normal, curvature, and surface area from unordered data points residing on a surface. This capability relaxes front-tracking's reliance on connectivity between interfacial points and allows front-tracking to model topological changes at an interface naturally. We use this capability in 2D and 3D front-tracking calculations to model coalescence. We also describe a simple projection scheme which allows us to suppress parasitic currents in front-tracking models. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Torres, DJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 32 TC 83 Z9 85 U1 0 U2 12 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD DEC 10 PY 2000 VL 165 IS 2 BP 620 EP 644 DI 10.1006/jcph.2000.6635 PG 25 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 393ZY UT WOS:000166500600014 ER PT J AU Xu, YS Shankland, TJ Poe, BT AF Xu, YS Shankland, TJ Poe, BT TI Laboratory-based electrical conductivity in the Earth's mantle SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID TEMPERATURE PROFILE; SILICATE PEROVSKITE; HIGH-PRESSURE; OLIVINE; PYROXENE; MINERALOGY; TRANSITION; BENEATH; ALUMINA; PHASES AB Recent laboratory measurements of electrical conductivity of mantle minerals are used in forward calculations for mantle conditions of temperature and pressure. The electrical conductivity of the Earth's mantle is influenced by many factors, which include temperature, pressure, the coexistence of multiple mineral phases, and oxygen fugacity. Ln order to treat these factors and to estimate the resulting uncertainties, we have used a variety of spatial averaging schemes for mixtures of the mantle minerals and have incorporated effects of oxygen fugacity. In addition, to better calculate lower mantle conductivities, we report new measurements for electrical conductivity of magnesiowustite (Mg0.89Fe0.11)O. Because the effective medium theory averages lie between the Hashin-Shtrikman bounds for the whole mantle, a laboratory-based conductivity-depth profile was constructed using this averaging scheme. Comparison of apparent resistivities calculated from the laboratory-based conductivity profile with those from field geophysical models shows that the two approaches agree well. C1 Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany. Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. RP Xu, YS (reprint author), Univ Minnesota, Dept Geol & Geophys, 310 Pillsbury Dr SE,108 Pillsbury Hall, Minneapolis, MN 55455 USA. EM xuxxx050@tc.umn.edu; shanklan@lanl.gov; brent.poe@uni-bayreuth.de NR 57 TC 114 Z9 127 U1 3 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD DEC 10 PY 2000 VL 105 IS B12 BP 27865 EP 27875 DI 10.1029/2000JB900299 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 387HQ UT WOS:000166117500002 ER PT J AU Velasco, AA Ammon, CJ Beck, SL AF Velasco, AA Ammon, CJ Beck, SL TI Broadband source modeling of the November 8, 1997, Tibet (M-w=7.5) earthquake and its tectonic implications SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID COMPLEX BODY WAVES; MACQUARIE RIDGE EARTHQUAKE; EMPIRICAL GREENS-FUNCTION; FAULT PLANE SOLUTIONS; 1989 LOMA-PRIETA; SOURCE PARAMETERS; RUPTURE PROCESS; ACTIVE TECTONICS; SURFACE-WAVES; UPPER MANTLE AB We studied the source process of a large (M-s = 7.9) intraplate earthquake that occurred on November 8, 1997, at 1002 UT in a remote region of northern Tibet. We used four distinct methods to investigate the broadband source process and thereby better understand the tectonic implications of this event; We relocated aftershocks using a master event technique and found that the distribution of aftershocks covers a region of 200 km in lateral extent. We also employed a surface wave spectral inversion technique to estimate the mainshock moment, depth, centroid location, and centroid time and utilized an empirical Green's function technique to extract rupture directivity information and a detailed source time function from observed seismograms. We also inverted body waves to estimate the moment release along the fault and the source time function. The 1997 earthquake ruptured a strike-slip fault that appears to be an extension or splay of the Kun Lun fault system. This fault is one of the most seismically active strike-slip faults within the Tibetan plateau; and has had events with surface wave magnitudes of 6.1, 7.4, and 7.9 in this region since 1973. The rupture released most of the energy within the first 20 s and propagated bilaterally initially, with the later rupture propagating westward for 20-30 s. The absence of large aftershocks suggests that the earthquake efficiently released the stored strain. Comparing mainshock to the largest aftershock energy ratios for this event and other large strike-slip events shows that faulting within the plateau has the characteristics of weak faults (e.g., fracture zone faulting). C1 Univ Calif Los Alamos Natl Lab, Los Alamos Seism Res Ctr, Los Alamos, NM 87545 USA. St Louis Univ, Dept Earth & Atmospher Sci, St Louis, MO 63103 USA. Univ Arizona, So Arizona Seism Observ, Dept Geosci, Tucson, AZ 85721 USA. RP Velasco, AA (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos Seism Res Ctr, POB 1663,MS D408, Los Alamos, NM 87545 USA. EM velasco@lanl.gov; ammon@eas.slu.edu; beck@geo.arizona.edu RI Velasco, Aaron/H-2666-2012 NR 66 TC 33 Z9 34 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD DEC 10 PY 2000 VL 105 IS B12 BP 28065 EP 28080 DI 10.1029/2000JB900282 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 387HQ UT WOS:000166117500015 ER PT J AU Soukoulis, CM Tringides, MC Velgakis, MJ AF Soukoulis, CM Tringides, MC Velgakis, MJ TI Growth kinetics of a nonequilibrium Ising model SO MODERN PHYSICS LETTERS B LA English DT Article ID CHEMISORBED OVERLAYER; ORDERING KINETICS; DIFFUSION; W(110); OXYGEN AB The growth kinetics of a system with spin-exchange dynamics has been investigated by means of computer simulations. These systems are used to simulate diffusive processes and kinetic phenomena far away from equilibrium. As a measure of growth we have studied the mean square displacement ( of tagged particles. It is found that t(1-n) follows a sublinear time dependence, which is explained in terms of the changes of the distribution of atoms between sites within the ordered region and sites of the domain boundaries. The time-dependence of the diffusion coefficient has been derived. The analogies to the relaxation in disordered systems, such as in a:Si-H and in O/W(110), is discussed. C1 Univ Patras, Dept Engn Sci, GR-26110 Patras, Greece. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. RP Velgakis, MJ (reprint author), Univ Patras, Dept Engn Sci, GR-26110 Patras, Greece. NR 14 TC 0 Z9 0 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0217-9849 J9 MOD PHYS LETT B JI Mod. Phys. Lett. B PD DEC 10 PY 2000 VL 14 IS 27-28 BP 983 EP 993 DI 10.1142/S0217984900001245 PG 11 WC Physics, Applied; Physics, Condensed Matter; Physics, Mathematical SC Physics GA 410LZ UT WOS:000167442600006 ER PT J AU Kendelewicz, T Liu, P Doyle, CS Brown, GE AF Kendelewicz, T Liu, P Doyle, CS Brown, GE TI Spectroscopic study of the reaction of aqueous Cr(VI) with Fe3O4(111) surfaces SO SURFACE SCIENCE LA English DT Article DE chromium; iron oxide; near edge extended X-ray absorption fine structure (NEXAFS); solid-liquid interfaces; surface chemical reaction; synchrotron radiation photoelectron spectroscopy; X-ray absorption spectroscopy ID X-RAY-ABSORPTION; TRANSITION-METAL COMPOUNDS; 2P PHOTOELECTRON-SPECTRA; ELECTRONIC-STRUCTURE; IRON-OXIDES; CR; PHOTOEMISSION; CHEMISTRY; CHROMIUM; HEMATITE AB We have used soft X-ray core-level photoemission and adsorption spectroscopies to study the reaction of aqueous sodium chromate solutions (50 muM Na2CrO4, pH 6 and 8.5) with clean surfaces of magnetite (111) prepared under UHV conditions. Chromium 2p photoemission and Cr L-edge absorption spectra indicate that tetrahedrally coordinated Cr(VI)(aq), which reacts with magnetite (111), is reduced by a heterogeneous redox process to octahedrally coordinated Cr(III) and incorporated in an overlayer on the magnetite. The thickness of the reacted overlayer at pH 6 increases with increasing immersion time in the Na2CrO4 solution for up to approximate to 10 min but remains unchanged for longer immersion times. The reaction rate is initially fast and follows a logarithmic law. When the passivated magnetite can no longer reduce Cr(VI)(aq), the passivating overlayer is 15+/-5 Angstrom thick and consists of a chromium oxyhydroxide or hydroxide phase with only trace amounts of iron. Evidence for extensive hydroxylation in the overlayer is provided by a chemically shifted component in both the O Is photoemission and OK-edge absorption spectra. The overlayer appears to lack long-range order based on loss of the first EXAFS-like feature in the O Kedge spectrum with increasing immersion time. Clear evidence for oxidation of Fe(II) to Fe(III) in the magnetite surface during reduction of Cr(VI)(aq), to Cr(III) is provided by Fe 2p photoemission and Fe L-edge absorption spectra. Strong attenuation of the Fe 2p signal during the first 10 min of the redox reaction indicates that iron does not outdiffuse significantly into the overlayer. At pH 8.5, the reaction follows a similar path, but its rate is lower, and Cr(VI)(aq) reduction continues for immersion times of up to 1 h. The results of this study are compared with results from an earlier XPS study of the passivation of zero-valent iron by chromate solutions [E. McCafferty, M.K. Bernett, J.S. Murday, Corros. Sci. 28 (1988) 559]. The resulting overlayer compositions, thicknesses, and reaction rates are very similar for the two systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Surface & Aqueous Geochem Grp, Dept Geog & Environm Sci, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, SLAC, Stanford, CA 94309 USA. RP Kendelewicz, T (reprint author), Stanford Univ, Surface & Aqueous Geochem Grp, Dept Geog & Environm Sci, Stanford, CA 94305 USA. NR 57 TC 79 Z9 79 U1 6 U2 58 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD DEC 10 PY 2000 VL 469 IS 2-3 BP 144 EP 163 DI 10.1016/S0039-6028(00)00808-6 PG 20 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 388RF UT WOS:000166194900006 ER PT J AU Zalenskaya, IA Bradbury, EM Zalensky, AO AF Zalenskaya, IA Bradbury, EM Zalensky, AO TI Chromatin structure of telomere domain in human sperm SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Article DE telomere; chromatin; histones; sperm ID DEFINED GENOME ARCHITECTURE; FISSION YEAST; MEIOTIC PROPHASE; ORGANIZATION; CELLS; PROTEINS; NUCLEUS; DNA; CHROMOSOMES; MOVEMENT AB Telomeres in human sperm nucleus are clustered at the nuclear periphery. Chromosomes in the sperm are highly condensed with protamines, however, a small portion of DNA remains associated with histones; the role of the nucleohistone is unknown. To examine structure of the telomeric chromatin, the sperm nuclei were treated with micrococcal nuclease. Chromatin released by the digestion was free from protamines, but contained histones and revealed nucleosomal organization. It was enriched with telomeric DNA organized into closely spaced nucleosomes with a periodicity of 148 +/- bp. Thus, while the most of the sperm genome is packed into extremely dense nucleoprotamine structure, at least a part of the telomeric DNA is arranged into nucleosomes and can be released by the nuclease. We suggest that telomeres might be among the first structures in the sperm nucleus that respond to oocyte signals for male pronucleus development at fertilization. (C) 2000 Academic Press. C1 Univ Calif Davis, Sch Med, Dept Biol Chem, Davis, CA 95616 USA. Univ Calif Los Alamos Natl Lab, Div Life Sci, Los Alamos, NM 87545 USA. RP Zalenskaya, IA (reprint author), Univ Calif Davis, Sch Med, Dept Biol Chem, Tupper Hall, Davis, CA 95616 USA. FU NICHD NIH HHS [HD39830] NR 35 TC 87 Z9 88 U1 2 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0006-291X J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD DEC 9 PY 2000 VL 279 IS 1 BP 213 EP 218 DI 10.1006/bbrc.2000.3917 PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 383GB UT WOS:000165873800034 PM 11112441 ER PT J AU Chu, WM Gong, X Li, ZW Takabayashi, K Ouyang, HH Chen, Y Lois, A Chen, DJ Li, GC Karin, M Raz, E AF Chu, WM Gong, X Li, ZW Takabayashi, K Ouyang, HH Chen, Y Lois, A Chen, DJ Li, GC Karin, M Raz, E TI DNA-PKcs is required for activation of innate immunity by immunostimulatory DNA SO CELL LA English DT Article ID DEPENDENT PROTEIN-KINASE; NF-KAPPA-B; CATALYTIC SUBUNIT; BACTERIAL-DNA; CPG MOTIFS; IKK-BETA; SEQUENCES; GENE; KU; PHOSPHORYLATION AB Bacterial DNA and related synthetic immunostimulatory oligodeoxyribonucleotides (ISS-ODN) stimulate innate immunity. However, the molecular recognition mechanism that initiates signaling in response to bacterial DNA and ISS-ODN has not been identified. Herein, we demonstrate that administration of bacterial DNA and ISS-ODN to mice lacking the catalytic subunit of DNA-PK (DNA-PKcs) and in vitro stimulation of BMDM from these mice result in defective induction of IL-6 and IL-12. Further analysis using BMDM of IKK beta (-/-) revealed that both DNA-PKcs and IKK beta are essential for normal cytokine production in response to ISS-ODN or bacterial DNA. ISS-ODN and bacterial DNA activate DNA-PK, which in turn contributes to activation of IKK and NF-kappaB. These results reveal a novel role of DNA-PKcs in innate immune responses and a link between DNA repair and innate immunity. C1 Univ Calif San Diego, Sam & Rose Stein Inst Res Aging, Dept Med 0663, La Jolla, CA 92093 USA. Univ Calif San Diego, Dept Pharmacol, Lab Signal Transduct & Gene Regulat, La Jolla, CA 92093 USA. Mem Sloan Kettering Canc Ctr, Dept Radiat Oncol, New York, NY 10021 USA. Mem Sloan Kettering Canc Ctr, Dept Med Phys, New York, NY 10021 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Raz, E (reprint author), Univ Calif San Diego, Sam & Rose Stein Inst Res Aging, Dept Med 0663, 9500 Gilman Dr, La Jolla, CA 92093 USA. FU NCI NIH HHS [CA-59609]; NIAID NIH HHS [AI 43477, AI 40682] NR 49 TC 146 Z9 154 U1 3 U2 10 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 USA SN 0092-8674 J9 CELL JI Cell PD DEC 8 PY 2000 VL 103 IS 6 BP 909 EP 918 DI 10.1016/S0092-8674(00)00194-X PG 10 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 382CR UT WOS:000165801300010 PM 11136976 ER PT J AU Tretiak, S Saxena, A Martin, RL Bishop, AR AF Tretiak, S Saxena, A Martin, RL Bishop, AR TI CEO/semiempirical calculations of UV-visible spectra in conjugated molecules SO CHEMICAL PHYSICS LETTERS LA English DT Article ID DENSITY-FUNCTIONAL THEORY; INTERMEDIATE NEGLECT; EXCITATION-ENERGIES; OPTICAL-EXCITATIONS; APPROXIMATION; SPECTROSCOPY; CAROTENOIDS; OLIGOMERS; STATES AB The collective electronic oscillators (CEO) approach based on the TDHF approximation is combined with INDO/S, MNDO, AMI, and PM3 semiempirical Hamiltonians. This technique is applied to compute and analyze the electronic structure of acceptor-substituted oligomers and conjugated polymers. Calculated excited-state energies and oscillator strengths agree well with the experimental data and with each other. In particular, the results using the Hamiltonians parameterized for ground-state calculations such as AMI and PM3 agree well with the INDO/S results. In addition, a two-dimensional analysis of the corresponding transition density matrices provides an efficient way for tracing the origin of various optical transitions by identifying the underlying changes in charge densities and bond-orders. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Tretiak, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Tretiak, Sergei/B-5556-2009 OI Tretiak, Sergei/0000-0001-5547-3647 NR 36 TC 26 Z9 26 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 8 PY 2000 VL 331 IS 5-6 BP 561 EP 568 DI 10.1016/S0009-2614(00)01009-5 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382YC UT WOS:000165854100031 ER PT J AU Longenecker, KL Zhang, BL Derewenda, U Sheffield, PJ Dauter, Z Parsons, JT Zheng, Y Derewenda, ZS AF Longenecker, KL Zhang, BL Derewenda, U Sheffield, PJ Dauter, Z Parsons, JT Zheng, Y Derewenda, ZS TI Structure of the BH domain from Graf and its implications for Rho GTPase recognition SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID FOCAL ADHESION KINASE; ACTIVATING-PROTEIN; CRYSTAL-STRUCTURE; P50RHOGAP; COMPLEX; BINDING; P190; P85 AB Cellular signaling by small G-proteins is down-regulated by GTPase-activating proteins (GAPs), which increase the rate of GTP hydrolysis, The GTPase regulator associated with focal adhesion kinase (Graf) exhibits GAP activity toward the RhoA and Cdc42 GTPases, but is only weakly active toward the closely related Rad. We determined the crystal structure of a 231-residue fragment of Graf (GrafGAP), a domain containing the GAP activity, at 2.4-Angstrom resolution The structure clarifies the boundaries of the functional domain and yields insight to the mechanism of substrate recognition. Modeling its interaction with substrate suggested that a favorable interaction with Glu-95 of Cdc42 (Glu-97 of RhoA) would be absent with the corresponding Ala-95 of Rad. Indeed, GrafGAP activity is diminished similar to 40-fold toward a Cdc42 E95A mutant, whereas a similar to 10-fold increase is observed for a Rad A95E mutant. The GrafGAP epitope that apparently interacts with Glu-95(Glu-97) contains Asn-225, which was recently found mutated in some myeloid leukemia patients. We conclude that position 95 of the GTPase is an important determinant for GrafGAP specificity in cellular function and tumor suppression. C1 Univ Virginia Hlth Syst, Dept Mol Physiol & Biol Phys, Charlottesville, VA 22908 USA. Univ Virginia Hlth Syst, Dept Microbiol, Charlottesville, VA 22908 USA. Univ Tennessee, Dept Biochem, Memphis, TN 38163 USA. NCI, Frederick, MD 21702 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Virginia, Ctr Canc, Charlottesville, VA 22908 USA. RP Derewenda, ZS (reprint author), Univ Virginia Hlth Syst, Dept Mol Physiol & Biol Phys, Charlottesville, VA 22908 USA. EM ZSD4N@virginia.edu RI Zheng, Yi/J-7235-2015 OI Zheng, Yi/0000-0001-7089-6074 FU NHLBI NIH HHS [HL48807]; NIGMS NIH HHS [GM60523] NR 27 TC 16 Z9 17 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD DEC 8 PY 2000 VL 275 IS 49 BP 38605 EP 38610 DI 10.1074/jbc.M007574200 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 381AH UT WOS:000165739800063 PM 10982819 ER PT J AU Lester, MI Pond, BV Anderson, DT Harding, LB Wagner, AF AF Lester, MI Pond, BV Anderson, DT Harding, LB Wagner, AF TI Exploring the OH plus CO reaction coordinate via infrared spectroscopy of the OH-CO reactant complex SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; WAVE-FUNCTIONS; CROSSED-BEAM; OH+CO; OH+CO->CO2+H; DYNAMICS AB A hydrogen-bonded complex of OH with CO is identified along the reaction coordinate for the OH+CO <----> HOCO -->H+CO2 reaction. The existence of this linear OH-CO complex is established by infrared action spectroscopy, which accesses vibrational stretching and bending modes of the complex. Complementary electronic structure calculations characterize the OH-CO and OH-OC complexes, the transition state for HOCO formation, and the reaction pathways that connect these complexes directly to the HOCO intermediate. (C) 2000 American Institute of Physics. [S0021-9606(00)02246-7]. C1 Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Lester, MI (reprint author), Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. NR 23 TC 95 Z9 95 U1 2 U2 15 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 8 PY 2000 VL 113 IS 22 BP 9889 EP 9892 AR PII [S0021-9606(00)02246-7] DI 10.1063/1.1330235 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LB UT WOS:000165584900002 ER PT J AU Wang, HB AF Wang, HB TI Basis set approach to the quantum dissipative dynamics: Application of the multiconfiguration time-dependent Hartree method to the spin-boson problem SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISCRETE VARIABLE REPRESENTATION; WAVE-PACKET; CH3I/MGO PHOTODISSOCIATION; APPROXIMATION; SCATTERING; SYSTEM; DISSOCIATION; ENVIRONMENT; MOLECULES; PYRAZINE AB The feasibility of using a basis set approach to the study of quantum dissipative dynamics is investigated for the spin-boson model, a system of two discrete states linearly coupled to a harmonic bath. The infinite Hamiltonian is discretized to a finite number of degrees of freedom. Traditional basis set approach, in a multiconfiguration time-dependent Hartree context, is used to solve the time-dependent Schrodinger equations by explicitly including all the degrees of freedom ("system"+"bath"). Quantities such as the reduced density matrix are then evaluated via a quadrature summation/Monte Carlo procedure over a certain number of time-dependent wave functions. Numerically exact results are obtained by systematically increasing the number of bath modes used to represent the condensed phase environment, as well as other variational parameters (number of basis functions, configurations, etc.). The potential of the current method is briefly discussed. (C) 2000 American Institute of Physics. [S0021-9606(00)51646-8]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Wang, HB (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Wang, Haobin/E-1208-2011 NR 33 TC 71 Z9 71 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 8 PY 2000 VL 113 IS 22 BP 9948 EP 9956 AR PII [S0021-9606(00)51646-8] DI 10.1063/1.1323746 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LB UT WOS:000165584900011 ER PT J AU Challacombe, M AF Challacombe, M TI Linear scaling computation of the Fock matrix. V. Hierarchical cubature for numerical integration of the exchange-correlation matrix SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL CALCULATIONS; ELECTRONIC-STRUCTURE CALCULATIONS; POLYATOMIC-MOLECULES; HARTREE-FOCK; BASIS-SETS; QUADRATURE; SCHEMES; RULES; CONSTRUCTION; SIMULATIONS AB Hierarchical cubature is a new method for achieving linear scaling computation of the exchange-correlation matrix central to Density Functional Theory. Hierarchical cubature combines a k-dimensional generalization of the binary search tree with adaptive numerical integration involving an entirely Cartesian grid. Hierarchical cubature overcomes strong variations in the electron density associated with nuclear cusps through multiresolution rather than spherical-polar coordinate transformations. This unique Cartesian representation allows use of the exact integration error during grid construction, supporting O(log N) range-queries that exploit locality of the Cartesian Gaussian based electron density. Convergence is controlled by tau (r), which bounds the local integration error of the electron density. An early onset of linear scaling is observed for RB3LYP/6-31G** calculations on water clusters, commencing at (H2O)(30) and persisting with decreasing values of tau (r). Comparison with nuclear weight schemes suggests that the new method is competitive on the basis of grid points per atom. Systematic convergence of the RPBE0/6-31G** Ne-2 binding curve is demonstrated with respect to tau (r). (C) 2000 American Institute of Physics. [S0021-9606(00)32442-4]. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Challacombe, M (reprint author), Los Alamos Natl Lab, Div Theoret, Grp T-12,MS B268, Los Alamos, NM 87545 USA. EM MChalla@LANL.Gov NR 64 TC 39 Z9 39 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 8 PY 2000 VL 113 IS 22 BP 10037 EP 10043 AR PII [S0021-9606(00)32442-4] DI 10.1063/1.1316012 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LB UT WOS:000165584900019 ER PT J AU Campbell, BJ Delgado, JM Cheetham, AK Iversen, BB Blake, NP Shannon, SR Latturner, S Stucky, GD AF Campbell, BJ Delgado, JM Cheetham, AK Iversen, BB Blake, NP Shannon, SR Latturner, S Stucky, GD TI The cation-vacancy ordering transition in dehydrated Na-6 sodalite SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID R(N)O(2N-2) HOMOLOGOUS SERIES; RAY-POWDER DIFFRACTION; INCOMMENSURATE PHASE; CRYSTAL-STRUCTURES; NEUTRON-SCATTERING; MODULATED STRUCTURES; ELECTRON-MICROSCOPY; RIETVELD REFINEMENT; SILVER SODALITE; QUARTZ AB Variable-temperature synchrotron x-ray powder diffraction data from dehydrated Na-6[Al6Si6O24] reveal a structural phase transition that involves both the commensurate ordering of the extra-framework Na cations and a one-dimensional incommensurate modulation of the framework. Peak splittings and superlattice reflections implicate an orthorhombically-distorted volume-doubled supercell at room temperature (a=12.9432 Angstrom, b=12.8403 Angstrom, and c=9.1372 Angstrom) similar to(root(2) over bara x root(2) over bar axa). These data also included additional superlattice peaks associated with an incommensurate long-period modulation with tau=(3/2 1/2 1)/8.9. All unique orderings of the 12 Na cations among the 16 available sites of the commensurate supercell are enumerated. A unique solution is identified that minimizes the structural energy and accounts for the observed superlattice peaks. Rietveld analysis reveals a significant Pauling "partial-collapse" tilt angle in the cation-ordered phase, that appears to decrease with increasing temperature. (C) 2000 American Institute of Physics. [S0021-9606(00)00844-8]. C1 Univ Calif Santa Barbara, Mat Res Lab, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Chem, Santa Barbara, CA 93106 USA. Univ Los Andes, Dept Chem, Merida 5251, Venezuela. RP Campbell, BJ (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Campbell, Branton/A-3990-2008 NR 52 TC 9 Z9 9 U1 1 U2 10 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 8 PY 2000 VL 113 IS 22 BP 10226 EP 10239 AR PII [S0021-9606(00)00844-8] DI 10.1063/1.1319351 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LB UT WOS:000165584900043 ER PT J AU Liu, DJ Evans, JW AF Liu, DJ Evans, JW TI Surface diffusion in mixed overlayers with superlattice ordering: Percolative transport around obstacles and along domain boundaries SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LATTICE-GAS; CHEMICAL DIFFUSION; DENSITY EXPANSION; PHASE-TRANSITIONS; FRONT PROPAGATION; ISING-MODELS; MONTE-CARLO; ADSORPTION; PARTICLES; CO AB To elucidate surface diffusion in the presence of a coadsorbate with superlattice ordering, we consider particle hopping on a square lattice with some fraction, theta (B), of quenched blocking sites arranged with checkerboard or c(2x2) ordering. Behavior for low theta (B) corresponds to diffusion around isolated obstacles, and can be described by exact density expansions. Behavior for high theta (B) corresponds to percolative diffusion along (or sometimes away from) domain boundaries. The connectivity of these domain boundaries is closely related to the existence of symmetry breaking [i.e., long-range c(2x2) order] in the distribution of blocking sites. In some cases, symmetry breaking induces critical behavior for diffusive transport which is fundamentally different from that for the conventional "ant in the labyrinth" problem. Our results apply to recently developed models for CO oxidation, where CO(ads) diffuses rapidly through coadsorbed relatively immobile c(2x2)-O(ads). The characterization of CO diffusion in these systems is key to describing spatial pattern formation. (C) 2000 American Institute of Physics. [S0021-9606(00)70146-2]. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Math, Ames, IA 50011 USA. RP Liu, DJ (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 52 TC 11 Z9 11 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 8 PY 2000 VL 113 IS 22 BP 10252 EP 10264 AR PII [S0021-9606(00)70146-2] DI 10.1063/1.1322356 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 378LB UT WOS:000165584900046 ER PT J AU Stroupe, C Brunger, AT AF Stroupe, C Brunger, AT TI Crystal structures of a Rab protein in its inactive and active conformations SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE G protein; Rab; Sec4; GDP; guanosine-5 '-(beta,gamma)-imidotriphosphate ID GUANINE-NUCLEOTIDE EXCHANGE; GTP-BINDING PROTEINS; TRANSPORT FACTOR-2 NTF2; GDP-BOUND FORM; EF-TS COMPLEX; ACTIVATING PROTEIN; STRUCTURE REFINEMENT; SECRETORY VESICLES; ESCHERICHIA-COLI; SEC4P AB We have determined crystal structures of Sec4, a member of the Rab family in the G protein superfamily, in two states: bound to GDP, and to a non-hydrolyzable GTP analog, guanosine-5'-(beta,gamma)-imidotriphosphate (GppNHp). This represents the first structure of a Rab protein bound to GDP. Sec4 in both states grossly resembles other G proteins bound to GDP and GppNHp. In Sec4-GppNHp, structural features common to active Rab proteins are observed. In Sec4-GDP, the switch I region is highly disordered and displaced relative to the switch I region of Ras-GDP. In two of the four molecules of Sec4-GDP in the asymmetric unit of the Sec4-GDP crystals, the switch II region adopts a conformation similar to that seen in the structure of the small G protein Ran bound to GDP. This allows residues threonine 76, glutamate 80, and arginine 81 of Sec4 to make contacts with other conserved residues and water molecules important for nucleotide binding. In the other two molecules in the asymmetric unit, these interactions do not take place. This structural variability in both the switch I and switch II regions of GDP-bound Sec4 provides a possible explanation for the high off-rate of GDP bound to Sec4, and suggests a mechanism for regulation of the GTPase cycle of Rab proteins by GDI proteins. (C) 2000 Academic Press. C1 Stanford Univ, Howard Hughes Med Inst, Stanford, CA 94305 USA. Stanford Univ, Dept Mol & Cellular Physiol, Stanford, CA 94305 USA. Stanford Univ, Dept Neurol & Neurol Sci, Stanford, CA 94305 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. RP Brunger, AT (reprint author), Stanford Univ, Howard Hughes Med Inst, Stanford, CA 94305 USA. OI Brunger, Axel/0000-0001-5121-2036 NR 66 TC 65 Z9 74 U1 1 U2 8 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD DEC 8 PY 2000 VL 304 IS 4 BP 585 EP 598 DI 10.1006/jmbi.2000.4236 PG 14 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 383HU UT WOS:000165877700008 PM 11099382 ER PT J AU Moss, WC Levatin, JL Szeri, AJ AF Moss, WC Levatin, JL Szeri, AJ TI A new damping mechanism in strongly collapsing bubbles SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE bubble dynamics; sonoluminescence; Rayleigh-Plesset equation ID SONOLUMINESCING BUBBLES; SINGLE; DYNAMICS; EMISSIONS AB A gas-filled bubble in a liquid undergoes cycles of growth, rapid collapse, and damped rebounds in response to a driving pressure. These nonlinear oscillations can be simulated using the Rayleigh Plesset equation (RPE), which was developed 50 years ago and is the foundation for almost all theoretical analyses of nonlinear bubble dynamics. A major deficiency of the RPE is that fur strongly driven bubbles, such as sonoluminescing bubbles, it produces large-amplitude rebounds that often last until the next: acoustic cycle of the periodic driving pressure. This is in contrast to the data, which show rapidly damped rebounds. Every derivation of the RPE assumes that the compressibility of the liquid gives rise to the damping. It is shown here that appreciable damping also comes from the most compressible part of the system, which is the gas; specifically, the damping arises from the inhomogeneous pressure field within a rapidly collapsing or expanding bubble. This simple physical reasoning generates a new modification of the RPE that better reproduces the extreme damping that is observed experimentally; a result that cannot be obtained with any other version of the RPE. Our results affect theoretical predictions of the limits of stability of sonoluminescing bubbles as well as theoretical predictions of the magnitude of acoustic emissions from collapsing bubbles. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Moss, WC (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. OI Szeri, Andrew/0000-0003-0407-2645 NR 29 TC 20 Z9 22 U1 1 U2 3 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD DEC 8 PY 2000 VL 456 IS 2004 BP 2983 EP 2994 PG 12 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 385ET UT WOS:000165990200008 ER PT J AU Marland, G Schlamadinger, B Matthews, R AF Marland, G Schlamadinger, B Matthews, R TI "Kyoto forests" and a broader perspective on management SO SCIENCE LA English DT Letter ID CARBON C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Joanneum Res, Inst Energy Res, A-8010 Graz, Austria. Alice Holt Res Stn, Mensurat Branch, Farnham GU10 4LH, Surrey, England. RP Marland, G (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 7 TC 0 Z9 0 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 8 PY 2000 VL 290 IS 5498 BP 1895 EP 1896 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 382EL UT WOS:000165810000021 PM 11144307 ER PT J AU Hughen, KA Southon, JR Lehman, SJ Overpeck, JT AF Hughen, KA Southon, JR Lehman, SJ Overpeck, JT TI Synchronous radiocarbon and climate shifts during the last deglaciation SO SCIENCE LA English DT Article ID NORTH-ATLANTIC; ATMOSPHERIC C-14/C-12; MELTWATER DISCHARGE; OCEAN CIRCULATION; YOUNGER DRYAS; TH-230 AGES; CAL BP; CALIBRATION; CORALS; GREENLAND AB Radiocarbon data from the Cariaco Basin provide calibration of the carbon-14 time scale across the period of deglaciation (15,000 to 10,000 years ago) with resolution available previously only from Holocene tree rings. Reconstructed changes in atmospheric carbon-14 are larger than previously thought, with the largest change occurring simultaneously with the sudden climatic cooling of the Younger Dryas event. Carbon-14 and published beryllium-10 data together suggest that concurrent climate and carbon-14 changes were predominantly the result of abrupt shifts in deep ocean ventilation. C1 Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02543 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Univ Arizona, Dept Geosci, Tucson, AZ 85721 USA. Univ Arizona, Inst Planet Earth, Tucson, AZ 85721 USA. RP Hughen, KA (reprint author), Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02543 USA. NR 34 TC 262 Z9 274 U1 3 U2 29 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD DEC 8 PY 2000 VL 290 IS 5498 BP 1951 EP 1954 DI 10.1126/science.290.5498.1951 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 382EL UT WOS:000165810000042 PM 11110659 ER PT J AU Lettieri, J Jia, Y Fulk, SJ Schlom, DG Hawley, ME Brown, GW AF Lettieri, J Jia, Y Fulk, SJ Schlom, DG Hawley, ME Brown, GW TI Optimization of the growth of epitaxial SrBi2Ta2O9 thin films by pulsed laser deposition SO THIN SOLID FILMS LA English DT Article DE epitaxy; laser ablation; oxides; X-ray diffraction ID SUPERCONDUCTORS; MICROSCOPY; EVOLUTION; FATIGUE AB The growth of epitaxial (001)-oriented SrBi2Ta2O9 thin films by pulsed laser deposition (PLD) has been investigated. The effects of target composition, substrate temperature, oxidant pressure, laser pulse rate, laser fluence, and sample cooling have been studied. Variation of deposition parameters significantly affects the phase purity and epitaxial perfection of these ferroelectrics, and individual and combinatorial effects of the aforementioned growth variables as related to the adsorption-controlled growth regime are discussed. X-Ray diffraction and Rutherford backscattering spectrometry (chi (min) = 12%) analyses indicate that the (001)-oriented epitaxial films grown under the optimized conditions identified in this study have the highest structural perfection reported to date. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16803 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Schlom, DG (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16803 USA. RI Schlom, Darrell/J-2412-2013 OI Schlom, Darrell/0000-0003-2493-6113 NR 28 TC 18 Z9 19 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD DEC 8 PY 2000 VL 379 IS 1-2 BP 64 EP 71 DI 10.1016/S0040-6090(00)01554-6 PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 389XX UT WOS:000166264900010 ER PT J AU Dannenberg, R Stach, E Groza, JR Dresser, BJ AF Dannenberg, R Stach, E Groza, JR Dresser, BJ TI TEM annealing study of normal grain growth in silver thin films SO THIN SOLID FILMS LA English DT Article DE grain boundary; growth mechanism; silver; sputtering ID NANOCRYSTALLINE COPPER; KINETICS AB Normal grain growth in 80-nm-thick sputter-deposited Ag films was studied via in situ heating stage transmission electron microscopy. The as-deposited films with an initial grain size of 40-50 nm were held at a series of temperatures tone per specimen) below 250 degreesC. A grain growth exponent n = 3 from the law D-n - D-o(n) = k(T)t was calculated by minimizing the deviation in the fitting function to the experimental data. An activation energy for grain growth of 0.53 eV (53 kJ/mol) is found, which is close to surface diffusion. These findings are consistent with our previous work on abnormal grain growth in Ag: that grain growth in thin film nanocrystalline silver is dominated by surface diffusion mass transport. (C) 2000 Elsevier Science B.V. All rights reserved. C1 BOC Coating Technol, Fairfield, CA 94533 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Chem Engn & Mat Sci, Davis, CA 95616 USA. RP Dannenberg, R (reprint author), AFG Dev Grp, 1311 Clegg St,Suite B, Petaluma, CA 94954 USA. RI Stach, Eric/D-8545-2011 OI Stach, Eric/0000-0002-3366-2153 NR 16 TC 48 Z9 51 U1 2 U2 23 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD DEC 8 PY 2000 VL 379 IS 1-2 BP 133 EP 138 DI 10.1016/S0040-6090(00)01570-4 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 389XX UT WOS:000166264900021 ER PT J AU Martin, PM Good, MS Johnston, JW Posakony, GJ Bond, LJ Crawford, SL AF Martin, PM Good, MS Johnston, JW Posakony, GJ Bond, LJ Crawford, SL TI Piezoelectric films for 100-MHz ultrasonic transducers SO THIN SOLID FILMS LA English DT Article DE aluminum nitride; piezoelectric effect; sputtering; zinc oxide AB Piezoelectric aluminum nitride (AlN) and zinc oxide (ZnO) thin films were deposited by reactive magnetron sputtering for use in ultrasonic transducers in the 100- to 300-MHz regime. Pulse-echo ultrasonic transducers are being developed to image subsurface microstructure in metal and non-metal (ceramic) materials and components. A Krimholtz, Leedom, Matthaei (KLM) model was used to aid in the design of the ultrasonic transducer. Design criteria included piezoelectric material properties and thickness, electrode material and thickness, substrate dielectric properties, active area diameter and bandwidth and sensitivity requirements. The preliminary designs consisted of Ni/AlN/Ni and Ni/ZnO/Ni on BK-7 glass and fused silica substrates. AIN was chosen because of its a high longitudinal wave velocity of 10 700 m/s and high dielectric strength of 20 MV/cm. Strongly oriented (002) AlN and ZnO coatings, up to 50 mum thick, were deposited onto transducer substrates. Transducers with strongly oriented (002) crystal orientation displayed the highest longitudinal/shear (L/S) wave ratio of 19.6 dB. Crystalline structure was found to depend primarily on substrate temperature, substrate placement, and substrate material. Substrate temperatures ranged between 100 and 400 degreesC. Strongly (002) oriented AlN films were deposited at substrate temperatures as low as 100 degreesC. The L/S ratio decreased with the onset of the (103) and other crystal orientations, which resulted from off-normal adatom flux incidence during deposition. Near normal incidence flux angles were needed to obtain the (002) crystal orientation. Substoichiometric ZnO films were obtained at substrate temperatures below 300 degreesC. The transducers operated at frequencies between 50 and 100 MHz, with performance very close to that of the design. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Martin, PM (reprint author), Pacific NW Natl Lab, 902 Battelle Blvd,POB 999,K3 59, Richland, WA 99352 USA. NR 10 TC 76 Z9 77 U1 4 U2 17 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD DEC 8 PY 2000 VL 379 IS 1-2 BP 253 EP 258 DI 10.1016/S0040-6090(00)01339-0 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 389XX UT WOS:000166264900038 ER PT J AU Mueller, JA Miller, JL Butler, LJ Qi, F Sorkhabi, O Suits, AG AF Mueller, JA Miller, JL Butler, LJ Qi, F Sorkhabi, O Suits, AG TI Internal energy dependence of the H+allene H+propyne product branching from the unimolecular dissociation of 2-propenyl radicals SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Letter ID PHOTODISSOCIATION; DYNAMICS; PROPYNE AB This Letter introduces a new technique to probe the competing unimolecular dissociation channels of isomerically-selected hydrocarbon radicals as a function of internal energy in the radical. The crossed laser-molecular beam scattering experiments produce 2-propenyl radicals by photolysis of 2-chloropropene and disperse the radicals by the neutral velocity imparted in the photolysis; thus dispersing them by internal energy in the neutral time-of-flight spectrum. For the unstable radicals, the experiments then measure the branching between the two competing C-H bond fission product channels via tunable vacuum-UV photoionization of the products. Dispersing the neutral products by arrival time at the detector allows us to measure the branching between isomeric product channels as a function of internal energy in the dissociating radical isomer. The data resolve the competition between the unimolecular H + allene and H + propyne product channels from the radical with internal energies from 0 to 18 kcal/mol above the H + propyne barrier. We find that the barrier to H + allene formation from this high-energy C3H5 radical is slightly higher than the barrier to H + propyne formation, in agreement with recent theoretical calculations but in sharp contrast to that predicted for the most stable C3H5 isomer, the allyl radical. The dominance of the branching to H + propyne formation over H + allene formation for this isomer persists at the higher internal energies in agreement with RRKM predictions that take into account the freezing of the methyl rotor in the H + allene channel and predict a concomitant reduction in the A factor for that channel. C1 Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Chem, Chicago, IL 60637 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Butler, LJ (reprint author), Univ Chicago, James Franck Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Qi, Fei/A-3722-2012 NR 11 TC 16 Z9 17 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD DEC 7 PY 2000 VL 104 IS 48 BP 11261 EP 11264 DI 10.1021/jp002439j PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 380WB UT WOS:000165725500002 ER PT J AU Grodkowski, J Dhanasekaran, T Neta, P Hambright, P Brunschwig, BS Shinozaki, K Fujita, E AF Grodkowski, J Dhanasekaran, T Neta, P Hambright, P Brunschwig, BS Shinozaki, K Fujita, E TI Reduction of cobalt and iron phthalocyanines and the role of the reduced species in catalyzed photoreduction of CO2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-METAL COMPLEXES; CARBON-DIOXIDE ACTIVATION; PHOTOCHEMICAL REDUCTION; ELECTROCATALYTIC REDUCTION; ELECTROCHEMICAL REDUCTION; ONE-ELECTRON; HOMOGENEOUS CATALYSIS; RADIOLYTIC REDUCTION; AQUEOUS-SOLUTIONS; TETRASODIUM SALT AB The role of cobalt and iron phthalocyanines in catalytic CO2 reduction has been studied. Chemical, photochemical, and radiolytic reductions of the metal phthalocyanines (Pc) have been carried out in organic solvents, and reduction of their tetrasulfonated derivatives (TSPc) in aqueous solutions. (CoPc)-Pc-II and (FePc)-Pc-II are readily reduced to [(CoPc)-Pc-I](-) and [F-I'Pc](-), which do not react with CO2. Reduction of [(CoPc)-Pc-I](-) yields a product which is characterized as the radical anion, [(CoPc.-)-Pc-I](2-), on the basis of its absorption spectra in the visible and IR regions. This species is stable under dry anaerobic conditions and reacts rapidly with CO2. Catalytic formation of CO and formate is confirmed by photochemical experiments in DMF and acetonitrile solutions containing triethylamine (TEA) as a reductive quencher. The photochemical yields are greatly enhanced by the addition of p-terphenyl (TP). The radical anion, TP.-, formed from the reductive quenching of the singlet excited state with TEA, reduces the phthalocyanines very rapidly. The rate constants for reduction of (CoPc)-Pc-II, [(CoPc)-Pc-I](-), and [(FePc)-Pc-I](-) by TP.-, determined by pulse radiolysis in DMF solutions, are nearly diffusion-controlled. The mono-reduced species formed from [(CoPc)-Pc-I](-) is unstable under the pulse radiolysis conditions but is longer-lived under the flash photolysis conditions. The interaction of this species with CO2 is either too weak or too slow to detect in the current experiments, where a competing reaction with protons predominates. C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Neta, P (reprint author), NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Brunschwig, Bruce/G-4249-2011; Fujita, Etsuko/D-8814-2013 NR 51 TC 76 Z9 76 U1 8 U2 56 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 DEC 7 PY 2000 VL 104 IS 48 BP 11332 EP 11339 DI 10.1021/jp002709y PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 380WB UT WOS:000165725500013 ER PT J AU Feller, D Dixon, DA Nicholas, JB AF Feller, D Dixon, DA Nicholas, JB TI Binding enthalpies for alkali cation-benzene complexes revisited SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; WAVE-FUNCTIONS; GAS-PHASE; AB-INITIO; SYSTEMATIC SEQUENCES; ENERGIES; ATOMS; WATER; 1ST-ROW AB The geometries and binding enthalpies of M+(benzene) complexes (M = Li, Na, K, Rb, and Cs) were obtained from large basis set second-order perturbation theory and coupled cluster theory calculations. The best DeltaH(298) estimates (in kcal/mol) are Li+(benzene) = -36.8 +/- 0.2 (theory) vs -37.9 and -39.3 +/- 3.2 (expt), Na+(benzene) = -24.7 +/- 0.3 (theory) vs -28.0 +/- 1.5 and -22.5 +/- 1.5 (expt), K+(benzene) = -20.1 +/- 0.4 (theory) vs -19.2 and -17.1 +/- 0.9 (expt), Rb+(benzene) = -16.4 +/- 0.2 (theory) vs -16.4 +/- 0.9 (expt), and Cs+(benzene) = -12.5 +/- 0.2 (theory) vs -15.1 +/- 1.1 (expt). The present findings include small corrections for core/valence correlation effects and lead to binding enthalpies uniformly larger than those of previous theoretical studies. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Feller, D (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, MK K8-91,POB 999, Richland, WA 99352 USA. NR 38 TC 96 Z9 96 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD DEC 7 PY 2000 VL 104 IS 48 BP 11414 EP 11419 DI 10.1021/jp002631l PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 380WB UT WOS:000165725500024 ER PT J AU Rodriguez, JA Dvorak, J Jirsak, T AF Rodriguez, JA Dvorak, J Jirsak, T TI Chemistry of SO2, H2S, and CH3SH on carbide-modified Mo(110) and Mo2C powders: Photoemission and XANES studies SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SUPPORTED MOLYBDENUM CARBIDE; SURFACE ELECTRONIC-STRUCTURE; THIOPHENE HYDRODESULFURIZATION; METAL-SURFACES; NITRIDE CATALYSTS; SULFUR-DIOXIDE; ADSORPTION; ALUMINA; DECOMPOSITION; SPECTROSCOPY AB The chemistry of SO2, H2S, and CH3SH on carbide-modified Mo(110) and powders of bulk Mo2C was studied using synchrotron-based high-resolution photoemission and X-ray absorption near-edge spectroscopy (XANES). These studies reveal that molybdenum carbide is very reactive toward sulfur-containing molecules, being able to break S-O, S-H, and S-C bonds at temperatures below 300 K. Upon adsorption of sulfur dioxide on molybdenum carbide at 150 or 300 K, there is dissociation of the adsorbate into S and O, and also formation of SO3 or SO4 by reaction with O adatoms sr disproportionation of SO2. The adsorbed SO3 and SO4 species decompose upon heating to 500 K leaving a heavily sulfided and oxidized carbide. In the case of H2S adsorption, the cleavage of the first H-S bond occurs at 80-100 K and the resulting HS intermediate transforms into S at temperatures below 250 K. Finally, for CH3SH on MoCx, the breaking of the C-S bond takes place at temperatures between 250 and 400 K. From 100 to 350 K, CH3S and a second S-containing species (CH,S) coexist on the surface of the carbide. A comparison to results reported in the literature indicates that the chemical reactivity of molybdenum carbide is similar to that of metallic Mo and much larger than that of molybdenum sulfide. The differences in the chemical reactivities of molybdenum carbide and molybdenum sulfide correlate well with changes in the electronic properties of Mo in these systems. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11953 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11953 USA. NR 77 TC 61 Z9 62 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 7 PY 2000 VL 104 IS 48 BP 11515 EP 11521 DI 10.1021/jp002792p PG 7 WC Chemistry, Physical SC Chemistry GA 380WD UT WOS:000165725700012 ER PT J AU Holroyd, RA Nishikawa, M Itoh, K AF Holroyd, RA Nishikawa, M Itoh, K TI Solvent clustering around pyrazine ions in the high-compressibility region of supercritical ethane SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID FLUIDS AB Pyrazine and methylpyrazine attach electrons reversibly in supercritical (SC) ethane in the interesting region near critical densities. Very rapid shifts in the attachment equilibrium occur over very narrow pressure ranges. Reaction volumes for electron attachment to these solutes range from -1.0 to -45 L/mol, depending on conditions. The agreement of the values of DeltaV(r) with the calculated values from the compressible continuum model is excellent, indicating that the model predicts the electrostriction volume by ions in SC ethane quite accurately, and also suggesting that the partial molar volumes of neutral pyrazine and methylpyrazine are small by comparison to that of the ions. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Kanazawa Inst Technol, Fac Engn, Astugi 2430292, Japan. Univ Tokyo, Dept Pure & Appl Sci, Tokyo 1538902, Japan. RP Holroyd, RA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 16 TC 15 Z9 15 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD DEC 7 PY 2000 VL 104 IS 48 BP 11585 EP 11590 DI 10.1021/jp002713+ PG 6 WC Chemistry, Physical SC Chemistry GA 380WD UT WOS:000165725700020 ER PT J AU Mukherjee, S Louie, SG Campbell, M Esserman, L Shyamala, G AF Mukherjee, S Louie, SG Campbell, M Esserman, L Shyamala, G TI Ductal growth is impeded in mammary glands of C-neu transgenic mice SO ONCOGENE LA English DT Article DE estrogen; estrogen receptor; C-neu; mammary gland; ductal growth ID HUMAN-BREAST-CANCER; PROGESTERONE RECEPTORS; ESTROGEN-RECEPTOR; ERBB RECEPTORS; A-FORM; EXPRESSION; MORPHOGENESIS; PROTOONCOGENE; ABNORMALITIES; SUPERFAMILY AB The steroid hormone, estradiol, is essential for both the growth of normal breast and induction of mammary carcinomas, The growth promoting effects of estrogen are presumed to be mediated by growth factors, in particular, epidermal growth factor, which mediates its effects through erbB receptors, erbB1 and erbB2/C-neu. C-neu is amplified and over-expressed in a large number of human cancers and transgenic mice over-expressing C-neu also develop mammary tumors, However, as set, the impact of C-neu over-expression on estrogen action during normal mammary development and hence, its precise role in carcinogenesis, remains unclear, In the present studies, we demonstrate that estradiol-dependent mammary ductal growth accompanying puberty is impaired in transgenic mice expressing wild type C-neu, and is intrinsic to the tissue. The impairment is not due to an overall impairment in estrogen action, since progesterone receptor expression is unaffected in C-neu mice. It is also not due to an intrinsic inability of the epithelial cells to proliferate, since impeded ductal growth co-exists,vith alveolar growth during pregnancy. Therefore, we propose that, depending on the physiological state, C-neu may either promote or inhibit the growth of mammary epithelial cells, and discuss its potential significance to carcinogenesis. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif San Francisco, Dept Surg, San Francisco, CA 94143 USA. RP Shyamala, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,Bldg 74, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA 66541] NR 36 TC 16 Z9 16 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0950-9232 J9 ONCOGENE JI Oncogene PD DEC 7 PY 2000 VL 19 IS 52 BP 5982 EP 5987 DI 10.1038/sj.onc.1203964 PG 6 WC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Oncology; Cell Biology; Genetics & Heredity GA 382MY UT WOS:000165827900004 PM 11146549 ER PT J AU Barate, R De Bonis, I Decamp, D Ghez, P Goy, C Jezequel, S Lees, JP Martin, F Merle, E Minard, MN Pietrzyk, B Bravo, S Casado, MP Chmeissani, M Crespo, JM Fernandez, E Fernandez-Bosman, M Garrido, L Grauges, E Lopez, J Martinez, M Merino, G Miquel, R Mir, LM Pacheco, A Paneque, D Ruiz, H Colaleo, A Creanza, D De Filippis, N de Palma, M Iaselli, G Maggi, G Maggi, M Nuzzo, S Ranieri, A Raso, G Ruggieri, E Selvaggi, G Silvestris, L Tempesta, P Tricomi, A Zito, G Huang, X Lin, J Ouyang, Q Wang, T Xie, Y Xu, R Xue, S Zhang, J Zhang, L Zhao, W Abbaneo, D Azzurri, P Barklow, T Boix, G Buchmuller, O Cattaneo, M Cerutti, F Clerbaux, B Dissertori, G Drevermann, H Forty, RW Frank, M Gianotti, F Greening, TC Hansen, JB Harvey, J Hutchcroft, DE Janot, P Jost, B Kado, M Lemaitre, V Maley, P Mato, P Minten, A Moutoussi, A Ranjard, F Rolandi, L Schlatter, D Schmitt, M Schneider, O Spagnolo, P Tejessy, W Teubert, F Tournefier, E Valassi, A Ward, JJ Wright, AE Ajaltouni, Z Badaud, F Dessagne, S Falvard, A Fayolle, D Gay, P Henrard, P Jousset, J Michel, B Monteil, S Montret, JC Pallin, D Pascolo, JM Perret, P Podlyski, F Hansen, JD Hansen, JR Hansen, PH Nilsson, BS Waananen, A Daskalakis, G Kyriakis, A Markou, C Simopoulou, E Vayaki, A Blondel, A Brient, JC Machefert, F Rouge, A Swynghedauw, M Tanaka, R Videau, H Focardi, E Parrini, G Zachariadou, K Antonelli, A Antonelli, M Bencivenni, G Bologna, G Bossi, F Campana, P Capon, G Chiarella, V Laurelli, P Mannocchi, G Murtas, F Murtas, GP Passalacqua, L Pepe-Altarelli, M Chalmers, M Halley, AW Kennedy, J Lynch, JG Negus, P O'Shea, V Raeven, B Smith, D Teixeira-Dias, P Thompson, AS Cavanaugh, R Dhamotharan, S Geweniger, C Hanke, P Hepp, V Kluge, EE Leibenguth, G Putzer, A Tittel, K Werner, S Wunsch, M Beuselinck, R Binnie, DM Cameron, W Davies, G Dornan, PJ Girone, M Marinelli, N Nowell, J Przysiezniak, H Sedgbeer, JK Thompson, JC Thomson, E White, R Ghete, VM Girtler, P Kneringer, E Kuhn, D Rudolph, G Bouhova-Thacker, E Bowdery, CK Clarke, DP Ellis, G Finch, AJ Foster, F Hughes, G Jones, RWL Pearson, MR Robertson, NA Smizanska, M Giehl, I Holldorfer, F Jakobs, K Kleinknecht, K Krocker, M Muller, AS Nurnberger, HA Quast, G Renk, B Rohne, E Sander, HG Schmeling, S Wachsmuth, H Zeitnitz, C Ziegler, T Bonissent, A Carr, J Coyle, P Curtil, C Ealet, A Fouchez, D Leroy, O Kachelhoffer, T Payre, P Rousseau, D Tilquin, A Aleppo, M Gilardoni, S Ragusa, F David, A Dietl, H Ganis, G Heister, A Huttmann, K Lutjens, G Mannert, C Manner, W Moser, HG Schael, S Settles, R Stenzel, H Wolf, G Boucrot, J Callot, O Davier, M Duflot, L Grivaz, JF Heusse, P Jacholkowska, A Serin, L Veillet, JJ Videau, I de Regie, JBD Yuan, C Zerwas, D Bagliesi, G Boccali, T Calderini, G Ciulli, V Foa, L Giammanco, A Giassi, A Ligabue, E Messineo, A Palla, F Rizzo, G Sanguinetti, G Sciaba, A Sguazzoni, G Steinberger, J Tenchini, R Venturi, A Verdini, PG Blair, GA Coles, J Cowan, G Green, MG Jones, LT Medcalf, T Strong, JA Clifft, RW Edgecock, TR Norton, PR Tomalin, IR Bloch-Devaux, B Boumediene, D Colas, P Fabbro, B Lancon, E Lemaire, MC Locci, E Perez, P Rander, J Renardy, JF Rosowsky, A Seager, P Trabelsi, A Tuchming, B Vallage, B Konstantinidis, N Loomis, C Litke, AM Taylor, G Booth, CN Cartwright, S Combley, F Hodgson, PN Lehto, M Thompson, LF Affholderbach, K Bohrer, A Brandt, S Grupen, C Hess, J Misiejuk, A Prange, G Sieler, U Borean, C Giannini, G Gobbo, B He, H Putz, J Rothberg, J Wasserbaech, S Armstrong, SR Cranmer, K Elmer, P Ferguson, DPS Gao, Y Gonzalez, S Hayes, OJ Hu, H Jin, S Kile, J McNamara, PA Nielsen, J Orejudos, W Pan, YB Saadi, Y Scott, IJ Shao, N von Wimmersperg-Toeller, JH Walsh, J Wiedenmann, W Wu, J Wu, SL Wu, X Zobernig, G AF Barate, R De Bonis, I Decamp, D Ghez, P Goy, C Jezequel, S Lees, JP Martin, F Merle, E Minard, MN Pietrzyk, B Bravo, S Casado, MP Chmeissani, M Crespo, JM Fernandez, E Fernandez-Bosman, M Garrido, L Grauges, E Lopez, J Martinez, M Merino, G Miquel, R Mir, LM Pacheco, A Paneque, D Ruiz, H Colaleo, A Creanza, D De Filippis, N de Palma, M Iaselli, G Maggi, G Maggi, M Nuzzo, S Ranieri, A Raso, G Ruggieri, E Selvaggi, G Silvestris, L Tempesta, P Tricomi, A Zito, G Huang, X Lin, J Ouyang, Q Wang, T Xie, Y Xu, R Xue, S Zhang, J Zhang, L Zhao, W Abbaneo, D Azzurri, P Barklow, T Boix, G Buchmuller, O Cattaneo, M Cerutti, F Clerbaux, B Dissertori, G Drevermann, H Forty, RW Frank, M Gianotti, F Greening, TC Hansen, JB Harvey, J Hutchcroft, DE Janot, P Jost, B Kado, M Lemaitre, V Maley, P Mato, P Minten, A Moutoussi, A Ranjard, F Rolandi, L Schlatter, D Schmitt, M Schneider, O Spagnolo, P Tejessy, W Teubert, F Tournefier, E Valassi, A Ward, JJ Wright, AE Ajaltouni, Z Badaud, F Dessagne, S Falvard, A Fayolle, D Gay, P Henrard, P Jousset, J Michel, B Monteil, S Montret, JC Pallin, D Pascolo, JM Perret, P Podlyski, F Hansen, JD Hansen, JR Hansen, PH Nilsson, BS Waananen, A Daskalakis, G Kyriakis, A Markou, C Simopoulou, E Vayaki, A Blondel, A Brient, JC Machefert, F Rouge, A Swynghedauw, M Tanaka, R Videau, H Focardi, E Parrini, G Zachariadou, K Antonelli, A Antonelli, M Bencivenni, G Bologna, G Bossi, F Campana, P Capon, G Chiarella, V Laurelli, P Mannocchi, G Murtas, F Murtas, GP Passalacqua, L Pepe-Altarelli, M Chalmers, M Halley, AW Kennedy, J Lynch, JG Negus, P O'Shea, V Raeven, B Smith, D Teixeira-Dias, P Thompson, AS Cavanaugh, R Dhamotharan, S Geweniger, C Hanke, P Hepp, V Kluge, EE Leibenguth, G Putzer, A Tittel, K Werner, S Wunsch, M Beuselinck, R Binnie, DM Cameron, W Davies, G Dornan, PJ Girone, M Marinelli, N Nowell, J Przysiezniak, H Sedgbeer, JK Thompson, JC Thomson, E White, R Ghete, VM Girtler, P Kneringer, E Kuhn, D Rudolph, G Bouhova-Thacker, E Bowdery, CK Clarke, DP Ellis, G Finch, AJ Foster, F Hughes, G Jones, RWL Pearson, MR Robertson, NA Smizanska, M Giehl, I Holldorfer, F Jakobs, K Kleinknecht, K Krocker, M Muller, AS Nurnberger, HA Quast, G Renk, B Rohne, E Sander, HG Schmeling, S Wachsmuth, H Zeitnitz, C Ziegler, T Bonissent, A Carr, J Coyle, P Curtil, C Ealet, A Fouchez, D Leroy, O Kachelhoffer, T Payre, P Rousseau, D Tilquin, A Aleppo, M Gilardoni, S Ragusa, F David, A Dietl, H Ganis, G Heister, A Huttmann, K Lutjens, G Mannert, C Manner, W Moser, HG Schael, S Settles, R Stenzel, H Wolf, G Boucrot, J Callot, O Davier, M Duflot, L Grivaz, JF Heusse, P Jacholkowska, A Serin, L Veillet, JJ Videau, I de Regie, JBD Yuan, C Zerwas, D Bagliesi, G Boccali, T Calderini, G Ciulli, V Foa, L Giammanco, A Giassi, A Ligabue, E Messineo, A Palla, F Rizzo, G Sanguinetti, G Sciaba, A Sguazzoni, G Steinberger, J Tenchini, R Venturi, A Verdini, PG Blair, GA Coles, J Cowan, G Green, MG Jones, LT Medcalf, T Strong, JA Clifft, RW Edgecock, TR Norton, PR Tomalin, IR Bloch-Devaux, B Boumediene, D Colas, P Fabbro, B Lancon, E Lemaire, MC Locci, E Perez, P Rander, J Renardy, JF Rosowsky, A Seager, P Trabelsi, A Tuchming, B Vallage, B Konstantinidis, N Loomis, C Litke, AM Taylor, G Booth, CN Cartwright, S Combley, F Hodgson, PN Lehto, M Thompson, LF Affholderbach, K Bohrer, A Brandt, S Grupen, C Hess, J Misiejuk, A Prange, G Sieler, U Borean, C Giannini, G Gobbo, B He, H Putz, J Rothberg, J Wasserbaech, S Armstrong, SR Cranmer, K Elmer, P Ferguson, DPS Gao, Y Gonzalez, S Hayes, OJ Hu, H Jin, S Kile, J McNamara, PA Nielsen, J Orejudos, W Pan, YB Saadi, Y Scott, IJ Shao, N von Wimmersperg-Toeller, JH Walsh, J Wiedenmann, W Wu, J Wu, SL Wu, X Zobernig, G CA ALEPH Collaboration TI Observation of an excess in the search for the Standard Model Higgs boson at ALEPH SO PHYSICS LETTERS B LA English DT Article ID E(+)E(-) COLLISIONS; DETECTOR; LEP; ENERGIES AB A search has been performed for the Standard Model Higgs boson in the data sample collected with the ALEPH detector at LEP, at centre-of-mass energies up to 209 GeV. An excess of 3 sigma beyond the background expectation is found, consistent with the production of the Higgs boson with a mass near 114 GeV/c(2). Much of this excess is seen in the four-jet analyses, where three high purity events are selected. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CNRS, Phys Particules Lab, IN2P3, F-74019 Annecy Le Vieux, France. Univ Autonoma Barcelona, Inst Fis Altes Energies, E-08193 Bellaterra, Barcelona, Spain. Ist Nazl Fis Nucl, Dipartimento Fis, Sez Bari, I-70126 Bari, Italy. Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China. CERN, European Lab Particle Phys, CH-1211 Geneva 23, Switzerland. Univ Clermont Ferrand, Phys Corpusculaire Lab, IN2P3, CNRS, F-63177 Clermont Ferrand, France. Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Democritos Nucl Res Ctr, GR-15310 Athens, Greece. Ecole Polytech, Lab Phys Nucl & Hautes Energies, IN2P3, CNRS, F-91128 Palaiseau, France. Univ Florence, Dipartimento Fis, Ist Nazl Fis Nucl, Sez Firenze, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Glasgow, Dept Phys & Astron, Glasgow G12 8QQ, Lanark, Scotland. Univ Heidelberg, Kirchhoff Inst Phys, D-69120 Heidelberg, Germany. Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2BZ, England. Univ Innsbruck, Inst Expt Phys, A-6020 Innsbruck, Austria. Univ Lancaster, Dept Phys, Lancaster LA1 4YB, England. Johannes Gutenberg Univ Mainz, Inst Phys, D-55099 Mainz, Germany. Univ Aix Marseille 2, Ctr Phys Particules Marseille, IN2P3, CNRS, F-13288 Marseille, France. Univ Milan, Dipartimento Fis, I-20133 Milan, Italy. Ist Nazl Fis Nucl, Sez Milano, I-20133 Milan, Italy. Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst Phys, D-80805 Munich, Germany. Univ Paris 11, Lab Accelerateur Lineaire, IN2P3, CNRS, F-91898 Orsay, France. Univ Pisa, Dipartimento Fis, Ist Nazl Fis Nucl, Sez Pisa, I-56010 Pisa, Italy. Scuola Normale Super Pisa, I-56010 Pisa, Italy. Univ London, Royal Holloway & Bedford New Coll, Dept Phys, Egham TW20 0EX, Surrey, England. Rutherford Appleton Lab, Particle Phys Dept, Didcot OX11 0QX, Oxon, England. CEA, DAPNIA, Serv Phys Particules, CE Saclay, F-91191 Gif Sur Yvette, France. Univ Calif Santa Cruz, Inst Particle Phys, Santa Cruz, CA 95064 USA. Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. Univ Siegen, Fachbereich Phys, D-57068 Siegen, Germany. Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy. Ist Nazl Fis Nucl, Sez Trieste, I-34127 Trieste, Italy. Univ Washington, Seattle, WA 98195 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Barcelona, Barcelona 08208, Spain. Univ Palermo, Dipartimento Fis & Tecnol Relat, Palermo, Italy. Dipartimento Fis, I-95129 Catania, Italy. Ist Nazl Fis Nucl, Sez Catania, I-95129 Catania, Italy. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. CNR, Ist Cosmogeofis, I-10133 Turin, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China. RP Barate, R (reprint author), CNRS, Phys Particules Lab, IN2P3, F-74019 Annecy Le Vieux, France. RI Chmeissani, Mokhtar/G-4346-2015; Mir, Lluisa-Maria/G-7212-2015; Hansen, John/B-9058-2015; Sguazzoni, Giacomo/J-4620-2015; Murtas, Fabrizio/B-5729-2012; Booth, Christopher/B-5263-2016; Pacheco Pages, Andres/C-5353-2011; Casado, Pilar/H-1484-2015; Ligabue, Franco/F-3432-2014; Fernandez, Enrique/L-5387-2014; ANTONELLI, ANTONELLA/C-6238-2011; Passalacqua, Luca/F-5127-2011; Focardi, Ettore/E-7376-2012; Venturi, Andrea/J-1877-2012; Palla, Fabrizio/F-4727-2012; Valassi, Andrea/K-7506-2012; Rolandi, Luigi (Gigi)/E-8563-2013; Colas, Paul/F-2876-2013; Ruiz, Hugo/H-4141-2013; Jones, Roger/H-5578-2011; O'Shea, Val/G-1279-2010; Bosman, Martine/J-9917-2014; Rizzo, Giuliana/A-8516-2015; OI Chmeissani, Mokhtar/0000-0002-2287-4791; Mir, Lluisa-Maria/0000-0002-4276-715X; Hansen, John/0000-0002-8422-5543; Sguazzoni, Giacomo/0000-0002-0791-3350; Booth, Christopher/0000-0002-6051-2847; Pacheco Pages, Andres/0000-0001-8210-1734; Casado, Pilar/0000-0002-0394-5646; Boccali, Tommaso/0000-0002-9930-9299; Ligabue, Franco/0000-0002-1549-7107; Fernandez, Enrique/0000-0002-6405-9488; Focardi, Ettore/0000-0002-3763-5267; Valassi, Andrea/0000-0001-9322-9565; Rolandi, Luigi (Gigi)/0000-0002-0635-274X; Jones, Roger/0000-0002-6427-3513; O'Shea, Val/0000-0001-7183-1205; Bosman, Martine/0000-0002-7290-643X; Bloch-Devaux, Brigitte/0000-0002-2463-1232; Tricomi, Alessia Rita/0000-0002-5071-5501; RASO, Giuseppe/0000-0002-5660-3711; Ciulli, Vitaliano/0000-0003-1947-3396; Rizzo, Giuliana/0000-0003-1788-2866; Cranmer, Kyle/0000-0002-5769-7094; Murtas, Fabrizio/0000-0002-7041-6541; Garrido Beltran, Lluis/0000-0001-8883-6539; Miquel, Ramon/0000-0002-6610-4836; Merino, Gonzalo/0000-0002-9540-5742 NR 19 TC 144 Z9 144 U1 0 U2 9 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 DEC 7 PY 2000 VL 495 IS 1-2 BP 1 EP 17 DI 10.1016/S0370-2693(00)01269-7 PG 17 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 387AN UT WOS:000166098100001 ER PT J AU Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Devmal, S Fernandez, A Fox, GF Gagnon, P Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lundberg, B Magnin, J MayTal-Beck, S Meadows, B Neto, JRTD Mihalcea, D Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Simao, FRA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stefanski, RJ Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yang, SM Yi, D Yoshida, S Zaliznyak, R Zhang, C AF Aitala, EM Amato, S Anjos, JC Appel, JA Ashery, D Banerjee, S Bediaga, I Blaylock, G Bracker, SB Burchat, PR Burnstein, RA Carter, T Carvalho, HS Copty, NK Cremaldi, LM Darling, C Denisenko, K Devmal, S Fernandez, A Fox, GF Gagnon, P Gobel, C Gounder, K Halling, AM Herrera, G Hurvits, G James, C Kasper, PA Kwan, S Langs, DC Leslie, J Lundberg, B Magnin, J MayTal-Beck, S Meadows, B Neto, JRTD Mihalcea, D Milburn, RH de Miranda, JM Napier, A Nguyen, A d'Oliveira, AB O'Shaughnessy, K Peng, KC Perera, LP Purohit, MV Quinn, B Radeztsky, S Rafatian, A Reay, NW Reidy, JJ dos Reis, AC Rubin, HA Sanders, DA Santha, AKS Santoro, AFS Schwartz, AJ Sheaff, M Sidwell, RA Simao, FRA Slaughter, AJ Sokoloff, MD Solano, J Stanton, NR Stefanski, RJ Stenson, K Summers, DJ Takach, S Thorne, K Tripathi, AK Watanabe, S Weiss-Babai, R Wiener, J Witchey, N Wolin, E Yang, SM Yi, D Yoshida, S Zaliznyak, R Zhang, C CA Fermilab E791 Collaboration TI Asymmetries in the production of Lambda(+)(c) and Lambda(-)(c) baryons in 500 GeV/c pi(-) nucleon interactions SO PHYSICS LETTERS B LA English DT Article ID D+; MESON AB We present a measurement of asymmetries in the production of Lambda (+)(c) and Lambda (-)(c) baryons in 500 GeV/c pi (-)-nucleon interactions from the E791 experiment at Fermilab. The asymmetries were measured as functions of Feynman x (x(F)) and transverse momentum squared (p(T)(2)) using a sample of 1819 +/- 62 Lambda (c)'s observed in the decay channel Lambda (+)(c) --> pK(-)pi (+). We observe more Lambda (+)(c) than Lambda (-)(c) baryons, with an asymmetry of (12.7 +/- 3.4 +/- 1.3)% independent of x(F) and p(T)(2) in our kinematical range (-0.1 less than or equal to x(F) less than or equal to 0.6 and 0.0 less than or equal to p(T)(2) less than or equal to 8.0 (GeV/c)(2)). This Lambda (c) asymmetry measurement is the first with data in both the positive and negative x(F) regions. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. CINVESTAV, Mexico City 07000, DF, Mexico. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. IIT, Chicago, IL 60616 USA. Kansas State Univ, Manhattan, KS 66506 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Mississippi, University, MS 38677 USA. Princeton Univ, Princeton, NJ 08544 USA. Univ Autonoma Puebla, Mexico City, DF, Mexico. Univ S Carolina, Columbia, SC 29208 USA. Stanford Univ, Stanford, CA 94305 USA. Tel Aviv Univ, IL-69978 Tel Aviv, Israel. Tufts Univ, Medford, MA 02155 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06511 USA. RP Magnin, J (reprint author), Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. RI Anjos, Joao/C-8335-2013; Gobel Burlamaqui de Mello, Carla /H-4721-2016; Fernandez Tellez, Arturo/E-9700-2017 OI Gobel Burlamaqui de Mello, Carla /0000-0003-0523-495X; Fernandez Tellez, Arturo/0000-0003-0152-4220 NR 20 TC 24 Z9 24 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 DEC 7 PY 2000 VL 495 IS 1-2 BP 42 EP 48 DI 10.1016/S0370-2693(00)01239-9 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 387AN UT WOS:000166098100005 ER PT J AU Carena, M Ellis, J Pilaftsis, A Wagner, CEM AF Carena, M Ellis, J Pilaftsis, A Wagner, CEM TI CP-violating MSSM Higgs bosoms in the light of LEP 2 SO PHYSICS LETTERS B LA English DT Article ID SUPERSYMMETRIC STANDARD MODEL; ELECTRIC-DIPOLE MOMENTS; RADIATIVE-CORRECTIONS; N=1 SUPERGRAVITY; MASS; NEUTRON; PHASES; RENORMALIZATION; SECTOR; UNIFICATION AB In the MSSM, the CP parities of the neutral Higgs bosons may be mixed by radiative effects induced by explicit CP violation in the third generation of squarks. To allow for this possibility, we argue that the charged Higgs-boson mass and tan beta should be used to parametrize the MSSM Higgs sector. We introduce a new benchmark scenario of maximal CP violation appropriate for direct searches of CP-violating MSSM Higgs bosons. We show that the bounds established by LEP 2 on the MSSM Higgs sector may be substantially relaxed at low and intermediate values of tan beta in the presence of CP violation, and comment on possible Higgs boson signatures at LEP 2 within this framework. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. CERN, Div Theory, CH-1211 Geneva 23, Switzerland. Univ Wurzburg, Inst Theoret Phys, D-97074 Wurzburg, Germany. Argonne Natl Lab, Div High Energy Phys, Argonne, IL 60439 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. RP Pilaftsis, A (reprint author), Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. EM apostolos.pilaftsis@cern.ch RI Ellis, John/J-2222-2012 OI Ellis, John/0000-0002-7399-0813 NR 69 TC 161 Z9 161 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD DEC 7 PY 2000 VL 495 IS 1-2 BP 155 EP 163 DI 10.1016/S0370-2693(00)01215-6 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 387AN UT WOS:000166098100020 ER PT J AU DeWoody, JA Fletcher, DE Wilkins, SD Nelson, WS Avise, JC AF DeWoody, JA Fletcher, DE Wilkins, SD Nelson, WS Avise, JC TI Genetic monogamy and biparental care in an externally fertilizing fish, the largemouth bass (Micropterus salmoides) SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE maternity; paternity; cuckoldry; mating system; sexual selection ID SMALLMOUTH BASS; SEXUAL SELECTION; DOLOMIEUI PISCES; PARENTAL CARE; CICHLID FISH; CENTRARCHIDAE; POPULATION; PATERNITY; SIZE AB Breeding, male North American sunfish (Centrarchidae), are often brightly coloured and promiscuous. However, the largemouth bass (Micropterus salmoides) is sexually monomorphic in appearance and socially monogamous. Unlike some other nest-tending centrarchids in the genus Lepomis, largemouth bass have also been reported to provide biparental care to eggs and fry. Here we use microsatellite markers in order to test whether social monogamy predicts genetic monogamy in the largemouth bass. Offspring were collected from 26 nests each usually guarded by a pair of adults, many of which were also captured. Twenty-three of these progeny cohorts (88%) proved to be composed almost exclusively of full-sibs and were thus the product of monogamous matings. Cuckoldry by males was rare. The genetic data also revealed that some nests contain juveniles that were not the progeny of the guardian female, a finding that can be thought of as low-level 'female cuckoldry'. Overall, however, the data provide what may be the first genetic documentation of near-monogamy and biparental care in a vertebrate with external fertilization. C1 Univ Georgia, Dept Genet, Athens, GA 30602 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. S Carolina Aquarium, Charleston, SC 29413 USA. RP DeWoody, JA (reprint author), Texas Tech Univ, Inst Environm & Human Hlth, Lubbock, TX 79409 USA. EM andrew.dewoody@tiehh.ttu.edu RI DeWoody, James/C-4909-2008 OI DeWoody, James/0000-0002-7315-5631 NR 32 TC 53 Z9 55 U1 3 U2 18 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8452 J9 P ROY SOC B-BIOL SCI JI Proc. R. Soc. B-Biol. Sci. PD DEC 7 PY 2000 VL 267 IS 1460 BP 2431 EP 2437 PG 7 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 386WZ UT WOS:000166088300012 PM 11133034 ER PT J AU Kim, HI Houston, JE AF Kim, HI Houston, JE TI Separating mechanical and chemical contributions to molecular-level friction SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID INTERFACIAL FORCE MICROSCOPY; SELF-ASSEMBLED MONOLAYERS; CH3-TERMINATED FILMS; CONTACT; ADHESION C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kim, HI (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 18 TC 48 Z9 49 U1 0 U2 5 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 DEC 6 PY 2000 VL 122 IS 48 BP 12045 EP 12046 DI 10.1021/ja003078o PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 380HZ UT WOS:000165696900056 ER PT J AU Zharkov, DO Gilboa, R Yagil, I Kycia, JH Gerchman, SE Shoham, C Grollman, AP AF Zharkov, DO Gilboa, R Yagil, I Kycia, JH Gerchman, SE Shoham, C Grollman, AP TI Role for lysine 142 in the excision of adenine from A : G mispairs by MutY DNA glycosylase of Escherichia coli SO BIOCHEMISTRY LA English DT Article ID SCHIFF-BASE INTERMEDIATE; MISMATCH REPAIR ENZYME; C-TERMINAL DOMAIN; SUBSTRATE-SPECIFICITY; CATALYTIC MECHANISM; CRYSTAL-STRUCTURE; ENDONUCLEASE-III; N-GLYCOSYLASE; G.A MISMATCH; PROTEIN AB MutY participates in the repair of oxidatively damaged DNA by excising adenine front dA: dG and dA:8-oxodG mispairs; this DNA glycosylase can be cross-linked to DNA through Lys-142. We have investigated the properties of a mutant protein in which Lys-142 is replaced by glutamine, Using the rifampicin resistance assay, MutY K142Q was shown to complement the mutY mutator phenotype to the same extent as wild-type MutY. Although MutY K142Q does not form a Schiff base with DNA, it retains in part the catalytic properties of wild-type enzyme. The K142Q mutation selectively impairs processing of DNA containing dA:dG mispairs but not that of substrates containing dA:8-oxodG, Decreased substrate processing is mediated primarily via an increase in K-D (21.8 nM for MutY vs 298 nM for MutY K142Q). The catalytic constant, measured in single turnover experiments, was not significantly affected. At pH < 6.0, the activity of MutY K142Q on the dA:dG mispair was approximately the same as for wild-type protein, suggesting that a dc(anti) to dG(syn) transition is effected at low pH. The three-dimensional structure of the catalytic domain of MutY K142Q, determined at 1.35 resolution, shows no significant differences between wild-type and mutant protein, indicating that Lys-142 is not critical for maintaining the conformation of MutY. We conclude that Lys-142 recognizes guanine in the dA:dG mispair, helping position this residue in the syn conformation and facilitating binding of substrate DNA, Lys-142 is not involved in the catalytic steps of base excision. C1 SUNY Stony Brook, Dept Pharmacol Sci, Biol Chem Lab, Stony Brook, NY 11794 USA. Russian Acad Sci, Novosibirsk Bioorgan Chem Inst, Siberian Div, Novosibirsk 630090, Russia. Hebrew Univ Jerusalem, Dept Inorgan Chem, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Lab Struct Chem & Biol, IL-91904 Jerusalem, Israel. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Grollman, AP (reprint author), SUNY Stony Brook, Dept Pharmacol Sci, Biol Chem Lab, Stony Brook, NY 11794 USA. RI Zharkov, Dmitry/K-2158-2012 OI Zharkov, Dmitry/0000-0001-5013-0194 FU NCI NIH HHS [CA17395] NR 55 TC 25 Z9 27 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD DEC 5 PY 2000 VL 39 IS 48 BP 14768 EP 14778 DI 10.1021/bi001538k PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 378XF UT WOS:000165610100008 PM 11101292 ER PT J AU Hargrove, WW Gardner, RH Turner, MG Romme, WH Despain, DG AF Hargrove, WW Gardner, RH Turner, MG Romme, WH Despain, DG TI Simulating fire patterns in heterogeneous landscapes SO ECOLOGICAL MODELLING LA English DT Article DE fire model; fire effects; cellular automaton; EMBYR; landscape model; patch formation; pattern; simulation; wildfire; Yellowstone National Park ID FOREST FIRES; CROWN FIRE; SPREAD; MODEL; PROPAGATION; FUELS; DISTURBANCE; DYNAMICS; CLIMATE; SHAPES AB A broad-scale probabilistic model of forest fires, EMBYR, has been developed to simulate the effects of large fires burning through heterogeneous landscapes. Fire ignition and spread are simulated on a gridded landscape by (1) examining each burning site at each time step, (2) independently evaluating the probability of spread to eight neighbors based on fuel type, fuel moisture, wind speed and direction, and (3) distributing firebrands to downwind sites, where the probability of ignition of new fires is a function of fuel type and moisture conditions. Low values for the probability of spread, I, produce a dendritic burn pattern resembling a slow, meandering fire, whereas higher values of I produce solid patterns similar to a rapidly moving, intensely burning fire. I had to be greater than a critical value, i(c), estimated to lie between 0.250 and 0.251, to have a 50% chance of propagating across the landscape by adjacent spread alone. The rate of spread of fire at I = 0.30 was nearly four times faster when firebrands were included in the simulations, and nearly eight times faster in the presence of moderate wind. Given the importance of firebrands in projecting fire spread, there is a need for better empirical information on fire spotting. A set of model parameters was developed to represent the weather conditions and fuel types on the subalpine plateau of Yellowstone National Park, WY, USA. Simulation experiments were performed to reveal relationships between fire and landscape-scale heterogeneity of fuels. In addition, EMBYR was used to explore fire patterns in the subalpine plateau by simulating four scenarios of weather and fuel conditions. The results of repeated simulations were compared by evaluating risk (the cumulative frequency distribution of the area burned) as a function of the change in weather conditions. Estimates of risk summarized the high degree of variability experienced in natural systems, the difficulty of predicting fire behavior when conditions are near critical thresholds, a quantification of uncertainties concerning future weather conditions, and useful tool for assessing potential wildfire effects. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Maryland, Ctr Environm Sci, Appalachian Lab, Frostburg, MD 21532 USA. Oak Ridge Natl Lab, Computat Phys & Engn Div, Oak Ridge, TN 37830 USA. Univ Wisconsin, Dept Zool, Madison, WI 53706 USA. Ft Lewis Coll, Dept Biol, Durango, CO 81301 USA. Natl Pk Serv, Yellowstone Natl Pk, WY 82190 USA. RP Gardner, RH (reprint author), Univ Maryland, Ctr Environm Sci, Appalachian Lab, 301 Braddock Rd, Frostburg, MD 21532 USA. RI Turner, Monica/B-2099-2010; Romme, William/C-7317-2016 NR 65 TC 128 Z9 142 U1 2 U2 55 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD DEC 5 PY 2000 VL 135 IS 2-3 BP 243 EP 263 DI 10.1016/S0304-3800(00)00368-9 PG 21 WC Ecology SC Environmental Sciences & Ecology GA 389PR UT WOS:000166247400008 ER PT J AU Asoo, B McNaney, JM Mitamura, Y Ritchie, RO AF Asoo, B McNaney, JM Mitamura, Y Ritchie, RO TI Cyclic fatigue-crack propagation in sapphire in air and simulated physiological environments SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE heart valve prostheses; sapphire; static fatigue; cyclic fatigue; crack growth ID STRESS-CORROSION; MECHANISM; CERAMICS; BEHAVIOR; GROWTH; MODEL AB Single-crystal aluminas are being considered for use in the manufacture of prosthetic heart valves. To characterize such materials for biomedical application, subcritical crack growth by stress corrosion (static fatigue) and by cyclic fatigue has been examined in sapphire along (1 (1) over bar 00) planes in 24 degrees C humid air and 37 degrees C Ringer's solution (the latter as a simulated physiological environment). The relationships between crack-propagation rates and the linear-elastic stress intensity have been determined for the first time in sapphire for both modes of subcritical cracking. It was found that growth rates were significantly faster at a given stress intensity in the Ringer's solution compared to the humid air environment. Mechanistically, a true cyclic fatigue effect was not found in sapphire as experimentally measured cyclic fatigue-crack growth rates could be closely predicted simply by integrating the static fatigue-crack growth data over the cyclic lending cycle. (C) 2000 John Wiley & Sons, Inc. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Hokkaido Univ, Dept Biomed Syst Engn, Sapporo, Hokkaido 0608628, Japan. RP Ritchie, RO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008; McNaney, James/F-5258-2013 OI Ritchie, Robert/0000-0002-0501-6998; NR 19 TC 16 Z9 16 U1 0 U2 4 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD DEC 5 PY 2000 VL 52 IS 3 BP 488 EP 491 DI 10.1002/1097-4636(20001205)52:3<488::AID-JBM6>3.0.CO;2-W PG 4 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 356CQ UT WOS:000089427100006 PM 11007616 ER PT J AU Karolyi, G Pentek, A Scheuring, I Tel, T Toroczkai, Z AF Karolyi, G Pentek, A Scheuring, I Tel, T Toroczkai, Z TI Chaotic flow: The physics of species coexistence SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID OPEN HYDRODYNAMICAL FLOWS; ADVECTION; EVOLUTION; BOUNDARIES; SCATTERING; LIFE AB Hydrodynamical phenomena play a keystone role in the population dynamics of passively advected species such as phytoplankton and replicating macromolecules. Recent developments in the field of chaotic advection in hydrodynamical flows encourage us to revisit the population dynamics of species competing for the same resource in an open aquatic system. If this aquatic environment is homogeneous and well-mixed then classical studies predict competitive exclusion of all but the most perfectly adapted species. In fact, this homogeneity is very rare, and the species of the community (at least on an ecological observation time scale) are in nonequilibrium coexistence. We argue that a peculiar small-scale, spatial heterogeneity generated by chaotic advection can lead to coexistence. In open flows this imperfect mixing lets the populations accumulate along fractal filaments, where competition is governed by an "advantage of rarity" principle. The possibility of this generic coexistence sheds light on the enrichment of phytoplankton and the information integration in early macromolecule evolution. C1 Univ Calif San Diego, Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA 92093 USA. Tech Univ Budapest, Dept Civil Engn Mech, H-1521 Budapest, Hungary. Eotvos Lorand Univ, Dept Plant Taxon & Ecol, Res Grp Ecol & Theoret Biol, H-1083 Budapest, Hungary. Eotvos Lorand Univ, Inst Theoret Phys, H-1518 Budapest, Hungary. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Pentek, A (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA 92093 USA. EM apentek@ucsd.edu RI Toroczkai, Zoltan/A-3421-2008; Karolyi, Gyorgy/A-5073-2008; Scheuring, Istvan/A-5368-2011; OI Toroczkai, Zoltan/0000-0002-6602-2849; Scheuring, Istvan/0000-0002-8108-8897; Karolyi, Gyorgy/0000-0002-1021-9554 NR 39 TC 82 Z9 83 U1 2 U2 15 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD DEC 5 PY 2000 VL 97 IS 25 BP 13661 EP 13665 DI 10.1073/pnas.240242797 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 380XH UT WOS:000165728800039 PM 11087815 ER PT J AU Yang, Z Sista, S Elmer, JW Debroy, T AF Yang, Z Sista, S Elmer, JW Debroy, T TI Three dimensional Monte Carlo simulation of grain growth during GTA welding of titanium SO ACTA MATERIALIA LA English DT Article DE grain growth; theory & modeling; Monte Carlo simulation; titanium; welding ID HEAT-AFFECTED ZONE; COMPUTER-SIMULATION; TRANSPORT PHENOMENA; STAINLESS-STEEL; FLUID-FLOW; POOL; TEMPERATURE; VAPORIZATION; FUNDAMENTALS; CONVECTION AB The work reported here represents significant advancement in the modeling of grain structure evolution in metallic systems. Utilizing computed temperature fields from a well tested heat transfer and fluid flow model, the evolution of grain structure was simulated for the first time using a three dimensional (3D) Monte Carlo model of grain growth in the heat affected zone of commercially pure titanium welds. The computed weld geometry and the simulated mean prior beta grain size for different heat inputs;agreed well with the corresponding experimental results when turbulence in the weld pool was considered. The grain sizes at Various locations equidistant from the fusion line were different, indicating that the results of previous 2D calculations need to be reexamined. The computed grain size distribution agreed well with the corresponding experimental data. The agreement indicates significant promise for understanding grain growth in the entire heat-affected zone using a comprehensive phenomenological model. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. AII rights reserved. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94551 USA. RP Debroy, T (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. RI DebRoy, Tarasankar/A-2106-2010 NR 36 TC 75 Z9 79 U1 6 U2 31 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 4 PY 2000 VL 48 IS 20 BP 4813 EP 4825 DI 10.1016/S1359-6454(00)00279-2 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 384QC UT WOS:000165955500006 ER PT J AU Engler, O AF Engler, O TI Deformation and texture of copper-manganese alloys SO ACTA MATERIALIA LA English DT Article DE cold working; copper alloys; X-ray diffraction (XRD); texture; computer simulation ID STACKING-FAULT ENERGY; POLYCRYSTALLINE FCC METALS; SHORT-RANGE ORDER; ROLLING TEXTURES; SINGLE-CRYSTALS; RECRYSTALLIZATION TEXTURES; PLASTIC-DEFORMATION; SOLID-SOLUTIONS; SHEAR BANDS; SLIP AB Manganese is the only element that can be dissolved in copper up to 12% without markedly changing the stacking fault energy (SFE). Hence, investigation of the deformation behaviour of Cu-h ln alloys may yield insight into the influence of alloying elements apart from the (usual) decrease in SFE. The development of the crystallographic texture is analysed in various Cu-Mn alloys that were deformed either in compression or by cold rolling. The texture development is simulated by means of a novel materials-dependent Taylor-deformation model. The spatial arrangement of the rolling texture orientations in the as-deformed microstructure is studied by an orientation-sensitive etching technique. Despite the constant SFE, with increasing Mn content the rolling textures change from the pure metal (copper) type towards the alloys (brass) type. This effect is attributed to the altered deformation behaviour as well as the increased tendency to form shear bands due to the large increase in strength of the Cu-Mn alloys. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div MST8, Los Alamos, NM 87545 USA. RP Engler, O (reprint author), Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div MST8, Mail Stop K765, Los Alamos, NM 87545 USA. NR 55 TC 68 Z9 73 U1 3 U2 19 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 4 PY 2000 VL 48 IS 20 BP 4827 EP 4840 DI 10.1016/S1359-6454(00)00272-X PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 384QC UT WOS:000165955500007 ER PT J AU Liu, YM Mitchell, TE Wadley, HNG AF Liu, YM Mitchell, TE Wadley, HNG TI Anisotropic damage evolution in a 0 degrees/90 degrees laminated ceramic-matrix composite SO ACTA MATERIALIA LA English DT Article DE acoustic; non-destructive testing; multilayers; ceramics; composites ID MECHANICAL-PROPERTIES; CRACK INITIATION; FIBER COMPOSITES; BRITTLE-MATRIX; BEHAVIOR; FAILURE; MODULI AB Anisotropic damage evolution in a 0 degrees /90 degrees laminated Nicalon(TM) SiC fiber-reinforced calcium aluminosilicate (CAS) glass-ceramic composite during uniaxial tensile deformation has been investigated using a variety of non-invasive characterization techniques. The elastic constant reduction in the three principal directions was measured from in situ laser-generated ultrasonic velocity measurements in various sound propagation directions. They indicate that, in addition to a large drop in elastic stiffness in the loading direction, the constants characterizing the nominal elastic stiffness transverse to the loading direction were also degraded. Surface replicas taken intermittently during loading revealed that transverse softening of the elastic stiffness was associated with fiber/matrix interface damage mainly in the 0 degrees plies, while the large softening of the elastic stiffness in the loading direction was the result of multiple matrix cracking in both the 0 degrees and 90 degrees plies. While the ultrasonic data allowed a detailed characterization of the anisotropic damage evolution in this laminate, acoustic emission measurements and surface replica data identified the crack initiation stress in the 90 degrees plies and correlated it to macroscopically observable deviations of the stress-strain curve from linear elastic behavior. These matrix cracks were found to have initiated preferentially in the weak 90 degrees plies near the 90 degrees /0 degrees ply boundaries. (C) 2000 Acm Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. Univ Virginia, Sch Engn & Appl Sci, Dept Mat Sci & Engn, Charlottesville, VA 22903 USA. RP Liu, YM (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Mail Stop K-765, Los Alamos, NM 87545 USA. NR 25 TC 6 Z9 6 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 4 PY 2000 VL 48 IS 20 BP 4841 EP 4849 DI 10.1016/S1359-6454(00)00286-X PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 384QC UT WOS:000165955500008 ER PT J AU Hsiung, LM Lassila, DH AF Hsiung, LM Lassila, DH TI Shock-induced deformation twinning and omega transformation in tantalum and tantalum-tungsten alloys SO ACTA MATERIALIA LA English DT Article DE shock-induced deformation twinning; phase transformations ID STRAIN-RATE DEFORMATION; PHASE TRANSFORMATION; METALS; BETA AB Effects of high strain-rate and high plastic-strain deformation on the development of deformation substructures in tantalum and tantalum-tungsten alloys (Ta-2.5 wt.% W and Ta-10 wt.% W) shocked at 15 and 45 GPa have been investigated, in addition to dislocation cells/walls, and (112)[111]-type deformation twinning, a shock-induced omega phase (hexagonal) is also found within polycrystalline tantalum shocked at 45 Gpa. The orientation relationships between the omega phase and parent (bcc) matrix are (10 (1) over bar0)(h)parallel to (211)(b),[0001](h)parallel to [11 1](b) and [1 (2) over bar 10](h)parallel to [0 (1) over bar1](b). The lattice parameters of omega phase are a(h)approximate to root 2a(b) = 0.468 nm and c(h)approximate to(root3/2)a(b) = 0.286 nm (c(h)/a(h) = 0.611). Since both deformation twinning and omega trans formation occur preferably in the (211)(b) planes with high resolved shear stresses, it is suggested that both can be considered as alternative paths for sheer transformations in shock-deformed tantalum. A greater volume fraction of twin and omega phase formed in Ta-W than in pure Ta reveals that shock-induced shear transformations can be promoted by solid solution alloying. While deformation twinning is resulted from 1/6[1 (1) over bar(1) over bar] homogeneous shear in consecutive (211) planes, omega transformation can be attributed to the 1/12 [1 (1) over bar(1) over bar], 1/3[1 (1) over bar(1) over bar] and 1/12[1 (1) over bar(1) over bar] inhomogeneous shear in consecutive (211) planes. Dislocation mechanisms for shock-induced twinning and omega transformation are proposed and critically discussed. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94551 USA. RP Hsiung, LM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, L-369,POB 808, Livermore, CA 94551 USA. NR 27 TC 90 Z9 92 U1 4 U2 37 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 4 PY 2000 VL 48 IS 20 BP 4851 EP 4865 DI 10.1016/S1359-6454(00)00287-1 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 384QC UT WOS:000165955500009 ER PT J AU Ahrenkiel, RK Johnston, SW Keyes, BM Friedman, DJ AF Ahrenkiel, RK Johnston, SW Keyes, BM Friedman, DJ TI Transport properties of GaAs1-xNx thin films grown by metalorganic chemical vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID BAND-GAP; ALLOYS; GAASN; RECOMBINATION; LIFETIME AB A series of devices with the structure GaAs/GaAs1-xNx/GaAs and 0.01 pi(+)pi(0)gamma decay SO PHYSICAL REVIEW LETTERS LA English DT Article ID NONLEPTONIC KAON DECAYS; CP VIOLATION; 500 MHZ; DETECTOR; SEARCH AB We have performed a measurement of the K+ --> pi (+)pi (0)gamma decay and have observed 2 X 10(4) events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7 +/- 0.8 +/- 0.3) X 10(-6) in the pi (+) kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. High Energy Accelerator Res Org, KEK, Tsukuba, Ibaraki 3050801, Japan. Osaka Univ, RCNP, Osaka 5670047, Japan. Princeton Univ, Joseph Henry Labs, Princeton, NJ 08544 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Univ Alberta, Ctr Subatom Res, Edmonton, AB T6G 2N5, Canada. Univ British Columbia, Dept Phys & Astron, Vancouver, BC V6T 1Z1, Canada. RP Adler, S (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 24 TC 20 Z9 21 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 4 PY 2000 VL 85 IS 23 BP 4856 EP 4859 DI 10.1103/PhysRevLett.85.4856 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100005 ER PT J AU Luk, KB Diehl, HT Duryea, J Guglielmo, G Heller, K Ho, PM James, C Johns, K Longo, MJ Rameika, R Teige, S Thomson, GB Zou, Y AF Luk, KB Diehl, HT Duryea, J Guglielmo, G Heller, K Ho, PM James, C Johns, K Longo, MJ Rameika, R Teige, S Thomson, GB Zou, Y CA Fermilab E756 Collaboration TI Search for direct CP violation in nonleptonic decays of charged Xi and Lambda hyperons SO PHYSICAL REVIEW LETTERS LA English DT Article ID MAGNETIC-MOMENT; PHASE-SHIFTS; NONCONSERVATION; POLARIZATION; INVARIANCE; SCATTERING AB A search for direct CP violation in the nonleptonic decays of hyperons has been performed. In comparing the product of the decay parameters, alpha (Xi)alpha (Lambda), in terms of an asymmetry parameter, A(Xi Lambda), between hyperons and antihyperons in the charged Xi --> Lambda pi and Lambda --> p pi decay sequence, we found no evidence of direct CP violation. The parameter A(Xi Lambda) was measured to be 0.012 +/- 0.014. C1 Univ Calif Berkeley, Div Phys, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Fermilab, Batavia, IL 60510 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Univ Minnesota, Sch Phys, Minneapolis, MN 55455 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. RP Luk, KB (reprint author), Univ Calif Berkeley, Div Phys, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 33 TC 21 Z9 22 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 DEC 4 PY 2000 VL 85 IS 23 BP 4860 EP 4863 DI 10.1103/PhysRevLett.85.4860 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100006 ER PT J AU Chemakin, I Cianciolo, V Cole, BA Fernow, R Frawley, AD Gilkes, M Gushue, S Hartouni, EP Hiejima, H Justice, M Kang, JH Kirk, H Maeda, N McGrath, RL Mioduszewski, S Morrison, D Moulson, M Namboodiri, MN Rai, G Read, K Remsberg, L Rosati, M Shin, Y Soltz, RA Sorensen, S Thomas, JH Torun, Y Winter, D Yang, X Zajc, WA Zhang, Y AF Chemakin, I Cianciolo, V Cole, BA Fernow, R Frawley, AD Gilkes, M Gushue, S Hartouni, EP Hiejima, H Justice, M Kang, JH Kirk, H Maeda, N McGrath, RL Mioduszewski, S Morrison, D Moulson, M Namboodiri, MN Rai, G Read, K Remsberg, L Rosati, M Shin, Y Soltz, RA Sorensen, S Thomas, JH Torun, Y Winter, D Yang, X Zajc, WA Zhang, Y TI Semi-inclusive Lambda and K-S production in p-Au collisions at 17.5 GeV/c SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUARK-GLUON PLASMA; NUCLEUS-NUCLEUS COLLISIONS; HEAVY-ION COLLISIONS; STRANGENESS ENHANCEMENT; PARTICLE-PRODUCTION; KAON; DISTRIBUTIONS; MULTIPLICITY; CENTRALITY; DEPENDENCE AB The first detailed measurements of the centrality dependence of strangeness production In p-A collisions are presented. Lambda and K-S dn/dy distributions from 17.5 GeV/c p-Au collisions are shown as a function of "grey" track multiplicity and the estimated number of collisions, nu, made by the proton. The nu dependence of the Lambda yield deviates from a scaling of p-p data by the number of participants, increasing faster than this scaling for nu less than or equal to 5 and saturating for larger nu. A slower growth in K-S multiplicity with nu is observed, consistent with a weaker nu dependence of K (K) over bar production than YK production. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Columbia Univ, New York, NY 10027 USA. Florida State Univ, Tallahassee, FL 32306 USA. Iowa State Univ, Ames, IA 50010 USA. Kent State Univ, Kent, OH 44242 USA. Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Univ Tennessee, Knoxville, TN 37996 USA. Yonsei Univ, Seoul 120749, South Korea. RP Chemakin, I (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. OI Thomas, James/0000-0002-6256-4536 NR 27 TC 14 Z9 14 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 DEC 4 PY 2000 VL 85 IS 23 BP 4868 EP 4871 DI 10.1103/PhysRevLett.85.4868 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100008 ER PT J AU Flink, C Feick, H McHugo, SA Seifert, W Hieslmair, H Heiser, T Istratov, AA Weber, ER AF Flink, C Feick, H McHugo, SA Seifert, W Hieslmair, H Heiser, T Istratov, AA Weber, ER TI Out-diffusion and precipitation of copper in silicon: An electrostatic model SO PHYSICAL REVIEW LETTERS LA English DT Article AB Concentrations of mobile interstitial copper and precipitated copper in silicon were studied after a high temperature intentional contamination and quench to room temperature. It was found that below a critical contamination the copper predominantly diffuses out to the surface, while for higher initial copper concentrations it mainly precipitates in the bulk. The critical copper contamination equals the acceptor concentration plus 10(16) cm(-3). This behavior can be explained by the electrostatic interaction between the positively charged interstitial copper and the forming copper precipitates. C1 Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Flink, C (reprint author), Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. OI Hieslmair, Henry/0000-0002-5842-1882 NR 19 TC 52 Z9 53 U1 0 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD DEC 4 PY 2000 VL 85 IS 23 BP 4900 EP 4903 DI 10.1103/PhysRevLett.85.4900 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100016 ER PT J AU Dodge, JS Weber, CP Corson, J Orenstein, J Schlesinger, Z Reiner, JW Beasley, MR AF Dodge, JS Weber, CP Corson, J Orenstein, J Schlesinger, Z Reiner, JW Beasley, MR TI Low-frequency crossover of the fractional power-law conductivity in SrRuO3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID ITINERANT FERROMAGNET SRRUO3; INFRARED CONDUCTIVITY; METALLIC OXIDES; THIN-FILMS; YBA2CU3O7; CRYSTAL; TEMPERATURE; RESISTIVITY; TRANSPORT; STATE AB We combine the results of terahertz time-domain spectroscopy with far-infrared transmission and reflectivity to obtain the conductivity of SrRuO3 over an unprecedented continuous range in frequency, allowing us to characterize the approach to zero frequency as a function of temperature. We show that the conductivity follows a simple phenomenological form, with an analytic structure fundamentally different from that predicted by the standard theory of metals. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Stanford Univ, Edward L Ginzton Lab, Stanford, CA 94305 USA. RP Dodge, JS (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Orenstein, Joseph/I-3451-2015 NR 23 TC 60 Z9 60 U1 2 U2 14 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 DEC 4 PY 2000 VL 85 IS 23 BP 4932 EP 4935 DI 10.1103/PhysRevLett.85.4932 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100024 ER PT J AU Kierfeld, J Nordborg, H Vinokur, VM AF Kierfeld, J Nordborg, H Vinokur, VM TI Theory of plastic vortex creep SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; FLUX-CREEP; BI2SR2CACU2O8 CRYSTALS; PHASE-TRANSITIONS; TOPOLOGICAL ORDER; MAGNETIZATION; LATTICES; DISORDER AB We develop a theory for plastic vortex creep in a topologically disordered (dislocated) vortex solid phase in type-II superconductors in terms of driven thermally activated dislocation dynamics. Plastic barriers for dislocations show a power-law divergence at small driving currents j, U-pl (j) proportional to j(- mu), With mu = 1 for a single dislocation and mu = 2/5 for creep of dislocation bundles. This implies a suppression of the creep rate at the transition from the ordered vortex phase (mu = 2/11) to the dislocated glass and can manifest itself as an observed increase of the apparent critical current (second peak). Our approach applies to general dynamics of disordered elastic media on a random substrate. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Kierfeld, J (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Kierfeld, Jan/A-2659-2009; OI Kierfeld, Jan/0000-0003-4291-0638; Nordborg, Henrik/0000-0003-3432-3257 NR 28 TC 47 Z9 47 U1 2 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 DEC 4 PY 2000 VL 85 IS 23 BP 4948 EP 4951 DI 10.1103/PhysRevLett.85.4948 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100028 ER PT J AU Birtcher, RC Donnelly, SE Schlutig, S AF Birtcher, RC Donnelly, SE Schlutig, S TI Nanoparticle ejection from Au induced by single Xe ion impacts SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOLECULAR-DYNAMICS; CLUSTER EMISSION; SURFACE DAMAGE; ENERGY; GOLD; SOLIDS; SPIKE; PARTICLES; DENSITY; METALS AB In situ transmission electron microscopy has been used to observe sputtered Au during Xe ion irradiation in transmission geometry. The sputtered Au was collected on an electron transparent carbon foil. Nanoparticles were observed on the collector foil after they were ejected by single ion impacts. The ejection is from the melt zone formed during the thermal spike phase of a displacement cascade produced near the surface by a single ion impact. Such single ion impacts are also capable of producing craters. Ejected nanoparticles can make a significant contribution to sputtering. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Salford, Joule Phys Lab, Salford M5 4WT, Lancs, England. Univ Caen, CIRIL Lab, CEA, CNRS, F-14070 Caen, France. RP Birtcher, RC (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Donnelly, Stephen/0000-0002-9749-5550 NR 29 TC 49 Z9 49 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 DEC 4 PY 2000 VL 85 IS 23 BP 4968 EP 4971 DI 10.1103/PhysRevLett.85.4968 PG 4 WC Physics, Multidisciplinary SC Physics GA 378YC UT WOS:000165612100033 ER PT J AU Fagan, BC Tipple, CA Xue, ZL Sepaniak, MJ Datskos, PG AF Fagan, BC Tipple, CA Xue, ZL Sepaniak, MJ Datskos, PG TI Modification of micro-cantilever sensors with sol-gels to enhance performance and immobilize chemically selective phases SO TALANTA LA English DT Article DE micro-cantilever sensors; sol-gels; chemically selective phases ID RESONATING MICROCANTILEVERS AB A chemical sensor based on the deflection of a surface modified silicon micro-cantilever is presented. A thin film of sol-gel was applied to one side of the micro-cantilever surface using a spin coating procedure. The sensor has been shown to give different responses to vapor phase analytes of varying chemical composition, as well as to varying concentrations of a given analyte. Ethanol, a highly polar molecule, exhibits a strong affinity for the polar sol-gel coating resulting in a large response; pentane, a non-polar hydrocarbon, shows very little response. The sol-gel coating has also been shown to function as a backbone for the immobilization of chemically selective phases on the cantilever surface. Reaction of the sol-gel him with chlorotriethoxysilane and subsequent capping of the remaining reactive surface silanols with hexamethyldisilizane increases the non-polar nature of the film. This results in an increase in the response of the sensor to non-polar analytes. The effects of film thickness and cantilever structure thickness on response were also investigated. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37919 USA. Oak Ridge Natl Lab, Engn Technol Div, Oak Ridge, TN 37831 USA. RP Sepaniak, MJ (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37919 USA. NR 31 TC 30 Z9 30 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-9140 J9 TALANTA JI Talanta PD DEC 4 PY 2000 VL 53 IS 3 BP 599 EP 608 DI 10.1016/S0039-9140(00)00533-6 PG 10 WC Chemistry, Analytical SC Chemistry GA 377QH UT WOS:000165524200015 PM 18968147 ER PT J AU Glaser, T Hedman, B Hodgson, KO Solomon, EI AF Glaser, T Hedman, B Hodgson, KO Solomon, EI TI Ligand K-edge X-ray absorption spectroscopy: A direct probe of ligand-metal covalency SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID ELECTRONIC-STRUCTURE; SULFUR COVALENCY; COPPER; SITE; COMPLEXES; PHOTOELECTRON; PLASTOCYANIN; BIOLOGY; OXIDASE; STATE AB Ligand K-edge X-ray absorption spectroscopy (XAS) is a new experimental probe of the covalency of a metal-ligand bond. The intensity of the ligand pre-edge feature is proportional to the mixing of ligand orbitals into the metal d orbitals. The methodology to determine covalencies in one-electron (hole) and many-electron systems is described and demonstrated for a series of metal tetrachlorides [MCl4](n-), metal tetrathiolates [M(SR)(4)](n-), and dimeric iron-sulfur (Fe-S) clusters [Fe2S2(SR)(4)](2-). It is there applied to blue Cu proteins, the Cu-A site, hydrogen bonding in Fe-S clusters, and the delocalization behavior in [2Fe-2S] vs [4Fe-4S] clusters. The covalencies determined in these studies provide important electronic structure insight into function. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Hedman, B (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. RI Glaser, Thorsten/H-5187-2013 OI Glaser, Thorsten/0000-0003-2056-7701 FU NCRR NIH HHS [RR-01209] NR 29 TC 185 Z9 185 U1 5 U2 51 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD DEC PY 2000 VL 33 IS 12 BP 859 EP 868 DI 10.1021/ar990125c PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA 388KY UT WOS:000166180700006 PM 11123885 ER PT J AU Harp, JM Hanson, BL Timm, DE Bunick, GJ AF Harp, JM Hanson, BL Timm, DE Bunick, GJ TI Asymmetries in the nucleosome core particle at 2.5 angstrom resolution SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID X-RAY-DIFFRACTION; HISTONE FOLD; DIELECTRIC-CONSTANT; CRYSTAL-STRUCTURE; DNA CURVATURE; SEQUENCE; PROGRAM; CRYOCRYSTALLOGRAPHY; CRYSTALLOGRAPHY; CRYSTALLIZATION AB The 2.5 Angstrom X-ray crystal structure of the nucleosome core particle presented here provides significant additions to the understanding of the nucleosome, the fundamental unit of chromatin structure. Extensions are made to the structure of the N-terminal histone tails and details are provided on hydration and ion binding. The structure is composed of twofold symmetric molecules, native chicken histone octamer cores and the DNA palindrome, which were expected to form a perfectly twofold symmetric nucleosome core particle. In fact, the result is asymmetric owing to the binding of the DNA to the protein surface and to the packing of the particles in the crystal lattice. An analysis is made of the asymmetries by comparisons both within the nucleosome core particle and to the structure of the histone octamer core of the nucleosome. C1 Univ Tennessee, Oak Ridge Natl Lab, Oak Ridge Program Genome Sci & Technol, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN 37831 USA. Indiana Univ, Sch Med, Dept Biochem & Mol Biol, Indianapolis, IN 46202 USA. RP Bunick, GJ (reprint author), Univ Tennessee, Oak Ridge Natl Lab, Oak Ridge Program Genome Sci & Technol, Oak Ridge, TN 37831 USA. RI Hanson, Bryant Leif/F-8007-2010 OI Hanson, Bryant Leif/0000-0003-0345-3702 FU NCRR NIH HHS [1P41RR1240801A1]; NIGMS NIH HHS [GM29818] NR 70 TC 164 Z9 168 U1 1 U2 7 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD DEC PY 2000 VL 56 BP 1513 EP 1534 DI 10.1107/S0907444900011847 PN 12 PG 22 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 377HX UT WOS:000165509100001 PM 11092917 ER PT J AU Von Dreele, RB Stephens, PW Smith, GD Blessing, RH AF Von Dreele, RB Stephens, PW Smith, GD Blessing, RH TI The first protein crystal structure determined from high-resolution X-ray powder diffraction data: a variant of T3R3 human insulin-zinc complex produced by grinding SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID STRUCTURE-REFINEMENT; PATTERNS AB X-ray diffraction analysis of protein structure is often limited by the availability of suitable crystals. However, the absence of single crystals need not present an insurmountable obstacle in protein crystallography any more than it does in materials science, where powder diffraction techniques have developed to the point where complex oxide, zeolite and small organic molecular structures can often be solved from powder data alone. Here, that fact is demonstrated with the structure solution and refinement of a new variant of the T3R3 Zn-human insulin complex produced by mechanical grinding of a polycrystalline sample. High-resolution synchrotron X-ray powder diffraction data were used to solve this crystal structure by molecular replacement adapted for Rietveld refinement. A complete Rietveld refinement of the 1630-atom protein was achieved by combining 7981 stereochemical restraints with a 4800-step (d(min) = 3.24 Angstrom) powder diffraction pattern and yielded the residuals R-wp = 3.73%, R-p = 2.84%, R-F(2) = 8.25%. It was determined that the grinding-induced phase change is accompanied by 9.5 and 17.2 degrees rotations of the two T3R3 complexes that comprise the crystal structure. The material reverts over 2-3 d to recover the original T3R3 crystal structure. A Rietveld refinement of this 815-atom protein by combining 3886 stereochemical restraints with a 6000-step (d(min) = 3.06 Angstrom) powder diffraction pattern yielded the residuals R-wp = 3.46%, R-p = 2.64%, R-F(2) = 7.10%. The demonstrated ability to solve and refine a protein crystal structure from powder diffraction data suggests that this approach can be employed, for example, to examine structural changes in a series of protein derivatives in which the structure of one member is known from a single-crystal study. C1 Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Hauptman Woodward Med Res Inst, Buffalo, NY 14203 USA. RP Von Dreele, RB (reprint author), Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, MS H805, Los Alamos, NM 87545 USA. FU NIGMS NIH HHS [GM56829] NR 26 TC 69 Z9 69 U1 1 U2 18 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD DEC PY 2000 VL 56 BP 1549 EP 1553 DI 10.1107/S0907444900013901 PN 12 PG 5 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 377HX UT WOS:000165509100004 PM 11092920 ER PT J AU Kuhn, P Deacon, AM Comsa, DS Rajaseger, G Kini, RM Uson, I Kolatkar, PR AF Kuhn, P Deacon, AM Comsa, DS Rajaseger, G Kini, RM Uson, I Kolatkar, PR TI The atomic resolution structure of bucandin, a novel toxin isolated from the Malayan krait, determined by direct methods (vol D56, pg 1401, 2000) SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Correction C1 Inst Mol & Cell Biol, Bioinformat Ctr, Singapore 117609, Singapore. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NUS, Fac Sci, Biosci Ctr, Singapore 119260, Singapore. Inst Inorgan Chem, D-37077 Gottingen, Germany. RP Kolatkar, PR (reprint author), Inst Mol & Cell Biol, Bioinformat Ctr, 30 Med Dr, Singapore 117609, Singapore. RI Kini, Manjunatha/H-8029-2012 NR 1 TC 2 Z9 2 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD DEC PY 2000 VL 56 BP 1702 EP 1702 DI 10.1107/S090744490001739X PN 12 PG 1 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 377HX UT WOS:000165509100036 ER PT J AU Tomsia, AP Moya, JS Thomas, G AF Tomsia, AP Moya, JS Thomas, G TI Proceedings of the Acta Materialia Workshop on "Ceramic and Bimaterial Interfaces: Designing for Properties" - 20-23 September 1999 Seville, Spain - Preface SO ACTA MATERIALIA LA English DT Editorial Material C1 CSIC, Inst Ciencia Mat, E-28049 Madrid, Spain. LBNL, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci, Berkeley, CA 94720 USA. RP Moya, JS (reprint author), CSIC, Inst Ciencia Mat, E-28049 Madrid, Spain. RI Moya, Jose/I-5841-2013 NR 0 TC 0 Z9 0 U1 2 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4363 EP 4363 DI 10.1016/S1359-6454(00)00222-6 PG 1 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000001 ER PT J AU Swiler, TP Loehman, RE AF Swiler, TP Loehman, RE TI Molecular dynamics simulations of reactive wetting in metal-ceramic systems SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Mat Inc, European Off Aerosp & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off naval Res Europe, Lawrence Berkeley Natl Lab DE wetting; ceramics; metals; surfaces & interfaces; computer simulation ID EMBEDDED-ATOM-METHOD; TRANSITION-METALS; SOLID-SURFACE; INTERFACES; OXIDE; POTENTIALS; ALUMINA; ALLOYS; FLUID AB We have simulated the wetting of sapphire by aluminum using the ES+ potential. This potential is unique among empirical potentials because it applies a combination of the embedded atom method (EAM) and Coulomb potentials on a system of atoms with defined electronegativities so that the atom charges as well as the interatomic forces and system energies found by typical empirical potentials can be determined. Because we do not have to specify atom bond character a priori, we can directly model reactive wetting where atoms from the metal droplet may replace cations in the ceramic substrate and undergo the appropriate change from metallic to ionic bonding. Also, by using this empirical potential, we can simulate large dynamic systems that cannot be simulated by first-principles methods, albeit with some loss in detail and accuracy. In our simulations of high-temperature wetting we observe the formation of an oxygen-deficient reaction layer between the liquid and the substrate. The driving force for the creation of this layer is the partial oxidation of the metallic aluminum, which results in partial reduction of the aluminum ions in the substrate and diffusion of oxygen from the substrate to the reaction layer. We believe that this change in stoichiometry at the metal-ceramic interface may influence diffusivities in the surface of the ceramic and may therefore have an important effect on the kinetics of the evolution of surface features observed experimentally during reactive wetting. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Adv Mat Lab, Albuquerque, NM 87106 USA. Univ New Mexico, Adv Mat Lab, Albuquerque, NM 87131 USA. RP Loehman, RE (reprint author), Sandia Natl Labs, Adv Mat Lab, 1001 Univ Blvd SE,Suite 100, Albuquerque, NM 87106 USA. NR 32 TC 29 Z9 31 U1 3 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4419 EP 4424 DI 10.1016/S1359-6454(00)00228-7 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000007 ER PT J AU Marks, RA Chapman, DR Danielson, DT Glaeser, AM AF Marks, RA Chapman, DR Danielson, DT Glaeser, AM TI Joining of alumina via copper/niobium/copper interlayers SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Materialia Inc, European Off Aerosp Res & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off Naval Res Europe, Lawrence Berkeley Natl Lab DE interface; mechanical properties; high temperature; joining; ceramic ID HIGH-TEMPERATURE APPLICATIONS; BONDED NB/AL2O3 INTERFACES; METAL CERAMIC INTERFACES; SILICON-NITRIDE; TRANSIENT LIQUID; MECHANICAL-PROPERTIES; OXYGEN DIFFUSION; FRACTURE ENERGY; LAYER TECHNIQUE; COPPER AB Alumina has been joined at 1150 degreesC and 1400 degreesC using multilayer copper/niobium/copper interlayers. Four-point bend strengths are sensitive to processing temperature, bonding pressure, and furnace environment (ambient oxygen partial pressure). Under optimum conditions, joints with reproducibly high room temperature strengths (approximate to 240+/-20 MPa) can be produced; most failures occur within the ceramic. Joints made with sapphire show that during bonding an initially continuous copper film undergoes a morphological instability, resulting in the formation of isolated copper-rich droplets/particles at the sapphire/interlayer interface, and extensive regions of direct bonding between sapphire and niobium. For optimized alumina bonds, bend tests at 800-1100 degreesC indicate significant strength is retained; even at the highest test temperature, ceramic failure is observed. Post-bonding anneals at 1000 degreesC in vacuum or in gettered argon were used to assess joint stability and to probe the effect of ambient oxygen partial pressure on joint characteristics. Annealing in vacuum for up to 200 h causes no significant decrease in room temperature bend strength or change in fracture path. With increasing anneal time in a lower oxygen partial pressure environment, the fracture strength decreases only slightly, but the fracture path shifts from the ceramic to the interface. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Glaeser, AM (reprint author), Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. EM aglaeser@sapphire.berkeley.edu NR 79 TC 37 Z9 38 U1 3 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4425 EP 4438 DI 10.1016/S1359-6454(00)00229-9 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000008 ER PT J AU Saiz, E Cannon, RM Tomsia, AP AF Saiz, E Cannon, RM Tomsia, AP TI Reactive spreading: Adsorption, ridging and compound formation SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Materialia Inc, European Off Aerosp Res & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off Naval Res Europe, Lawrence Berkeley Natl Lab DE ceramic; metallic; liquids; surfaces & interfaces; kinetics ID INTERFACIAL ENERGY; ALUMINA SYSTEMS; WETTABILITY; ALLOYS; KINETICS; ADHESION; SOLIDS; GRAPHITE; LIQUIDS; SURFACE AB Reactive spreading, in which a chemically active element is added to promote wetting of noble metals on nonmetallic materials, is evaluated mechanistically. Theories for the energetics and kinetics of the steps involved in spreading are outlined to permit comparison to the steps in the compound formation that typically accompanies reactive wetting. These include: fluid flow, active metal adsorption. including nonequilibrium effects, and triple line ridging. They can all be faster than compound nucleation under certain conditions. This analysis plus assessment of recently reported experiments on metal/ceramic systems lead to a focus on those conditions under which spreading proceeds ahead of the actual formation of a new phase at the interface. This scenario may be more typical than commonly believed, and perhaps is the most effective situation leading to enhanced spreading. A rationale for the slow spreading rates plus the pervasive variability and hysteresis observed during high-temperature wetting also emerges. (C) 2000 Elsevier Science Ltd. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP Saiz, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. EM esaiz@lbl.gov NR 67 TC 109 Z9 111 U1 1 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4449 EP 4462 DI 10.1016/S1359-6454(00)00231-7 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000010 ER PT J AU Becher, PF Painter, GS Sun, EY Hsueh, CH Lance, MJ AF Becher, PF Painter, GS Sun, EY Hsueh, CH Lance, MJ TI The importance of amorphous intergranular films in self-reinforced Si(3)N(4) ceramics SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Materialia Inc, European Off Aerosp Res & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off Naval Res Europe, Lawrence Berkeley Natl Lab DE ceramics; interfaces; microstructure; toughness; cluster calculations ID BETA-SILICON NITRIDE; IMPROVED FRACTURE-TOUGHNESS; R-CURVE RESPONSE; MICROSTRUCTURAL DESIGN; MECHANICAL-PROPERTIES; ELECTRONIC-STRUCTURE; OXYNITRIDE GLASSES; ATOMISTIC STRUCTURE; ALUMINA; COMPOSITES AB High-fracture-strength and high-toughness beta -Si(3)N(4) ceramics can be obtained by tailoring the size and number of the elongated bridging grains. However, these bridging mechanisms rely on debonding of the reinforcing grains from the matrix to increase toughness. Interfacial debonding is shown to be influenced by sintering aids incorporated in the amorphous intergranular films. In one case, the interface strength between the intergranular glass and the reinforcing grains increases with the aluminum and oxygen content of an interfacial epitaxial beta -SiAlON layer. In another, the incorporation of fluorine in the intergranular film allows the crack to circumvent the grains. Atomic cluster calculations reveal that these two debonding processes are related to (1) strong Si-O and Al-O bonding across the glass/crystalline interface with an epitaxial SiAlON layer and (2) a weakening of the amorphous network of the intergranular film when difluorine substitutes for bridging oxygen. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Becher, PF (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. EM Becherpf@ornl.gov RI Hsueh, Chun-Hway/G-1345-2011; Lance, Michael/I-8417-2016 OI Lance, Michael/0000-0001-5167-5452 NR 36 TC 55 Z9 55 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4493 EP 4499 DI 10.1016/S1359-6454(00)00236-6 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000015 ER PT J AU De Boer, MP Knapp, JA Michalske, TA Srinivasan, U Maboudian, R AF De Boer, MP Knapp, JA Michalske, TA Srinivasan, U Maboudian, R TI Adhesion hysteresis of silane coated microcantilevers SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Mat Inc, European Off Aerosp & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off naval Res Europe, Lawrence Berkeley Natl Lab DE surfaces & interfaces; thin films; aging; coating; adhesion hysteresis ID SELF-ASSEMBLED MONOLAYERS; SURFACES; SILICON; FRICTION; OCTADECYLTRICHLOROSILANE; INDENTATION; POLYSILICON; CONTACT; SOLVENT; FORCES AB We have developed a new experimental approach for measuring hysteresis in the adhesion between a free standing thin film and a substrate. By accurately measuring and modeling the deformations in micromachined cantilever beams that are subject to combined interfacial adhesive and applied electrostatic forces, we determine adhesion energies for advancing and receding contacts. We examined adhesion hysteresis for silane coated cantilevers and found no hysteresis at low relative humidity (RH) conditions. The dominant contribution to inter facial energy at low RH is van der Waals attraction between portions of the surfaces that are separated by nanometer asperities. In contrast, significant hysteresis was observed for surfaces that were exposed to high RH conditions. Atomic force microscopy studies of these surfaces showed spontaneous formation of silane mounds that have irreversibly transformed from initially uniform hydrophobic surface layers. Contact mechanics considerations show that the compliance of the mounds can reasonably allow microcapillaries in surrounding hydrophilic areas to bridge at high RH as the surfaces are forced into contact by an externally applied load, leading to the adhesion hysteresis. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Intelligent Micromachine Technol Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Radiat Solid Interact & Proc Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Biomol Mat & Interfaces Dept, Albuquerque, NM 87185 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP De Boer, MP (reprint author), Sandia Natl Labs, Intelligent Micromachine Technol Dept, POB 5800, Albuquerque, NM 87185 USA. RI de Boer, Maarten/C-1525-2013 OI de Boer, Maarten/0000-0003-1574-9324 NR 39 TC 66 Z9 66 U1 2 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4531 EP 4541 DI 10.1016/S1359-6454(00)00239-1 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000018 ER PT J AU Chen, D Sixta, ME Zhang, XF De Jonghe, LC Ritchie, RO AF Chen, D Sixta, ME Zhang, XF De Jonghe, LC Ritchie, RO TI Role of the grain-boundary phase on the elevated-temperature strength, toughness, fatigue and creep resistance of silicon carbide sintered with Al, B and C SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Mat Inc, European Off Aerosp & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off naval Res Europe, Lawrence Berkeley Natl Lab DE ceramics; fatigue; creep; strength; toughness; high temperature ID CYCLIC FATIGUE; CRACK-GROWTH; POLYCRYSTALLINE ALUMINA; NITRIDE CERAMICS; FRICTIONAL-WEAR; BEHAVIOR; OXIDATION; FRACTURE; SI3N4; FABRICATION AB The high-temperature mechanical properties, specifically strength, fracture toughness, cyclic fatigue-crack growth and creep behavior, of an in situ toughened silicon carbide, with Al, B and C sintering additives (ABC-SiC), have been examined at temperatures from ambient to 1500 degreesC with the objective of characterizing the role of the grain-boundary film/phase. It was found that the high strength, cyclic fatigue resistance and particularly the fracture toughness displayed by ABC-SiC at ambient temperatures was not severely compromised at elevated temperatures; indeed, the fatigue-crack growth properties up to 1300 degreesC were essentially identical to those at 25 degreesC, whereas resistance to creep deformation was superior to published results on silicon nitride ceramics. Mechanistically, the damage and shielding mechanisms governing cyclic Fatigue-crack advance were essentially unchanged between similar to 25 degreesC and 1300 degreesC, involving a mutual competition between intergranular cracking ahead of the crack rip and interlocking grain bridging in the crack wake. Moreover, creep deformation was not apparent below similar to 1400 degreesC, and involved grain-boundary sliding accommodated by diffusion along the interfaces between the grain-boundary film and SiC grains, with little evidence of cavitation. Such unusually good high-temperature properties in ABC-SiC are attributed to crystallization of the grain-boundary amorphous phase, which can occur either in situ, due to the prolonged thermal exposure associated with high-temperature fatigue and creep tests, or by prior heat treatment. Moreover, the presence of the crystallized grain-boundary phase did not degrade subsequent ambient-temperature mechanical properties; in fact, the strength, toughness and fatigue properties at 25 degreesC were increased slightly. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. RP Ritchie, RO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ritchie, Robert/A-8066-2008 OI Ritchie, Robert/0000-0002-0501-6998 NR 58 TC 65 Z9 66 U1 2 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4599 EP 4608 DI 10.1016/S1359-6454(00)00246-9 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000025 ER PT J AU Dragoo, AL AF Dragoo, AL TI The US Department of Energy's program on the fundamental material science of internal interfaces SO ACTA MATERIALIA LA English DT Article; Proceedings Paper CT Acta Materialia Workshop on Ceramic and Biomaterial Interfaces: Designing for Properties CY SEP 20-23, 1999 CL SEVILLE, SPAIN SP Spanish Natl Res Council, Minist Educ, Minist Ind, Univ Seville, Acta Materialia Inc, European Off Aerosp Res & Dev, USAF, Off Sci Res, USAF, Res Lab, USA, Res & Dev & Standardizat Grp, US Off Naval Res Europe, Lawrence Berkeley Natl Lab DE grain boundaries; bonding; computer simulation; theory & modeling, structural behavior; transmission electron microscopy (TEM) ID AMORPHOUS INTERGRANULAR FILMS; SOLUTE-INCORPORATED SRTIO3; IMPROVED FRACTURE-TOUGHNESS; GRAIN-BOUNDARY GEOMETRY; ELECTRONIC-STRUCTURE; MICROSTRUCTURAL DESIGN; COVALENT MATERIALS; SILICON-NITRIDE; PRISTINE; HOLOGRAPHY AB As part of a broad program on fundamental material science, the Department of Energy (DoE)/Basic Energy Sciences (BES)/Division of Materials Sciences and Engineering supports theoretical and experimental research on the structure and properties of interfaces. Interfaces, whether solid/solid, solid/liquid or solid/vapor, play critical roles in the properties of many materials and influence many processes. Hence, fundamental research on interfaces is relevant to meeting the long-term energy needs of the United States. The Division supports research on interfaces through its research grants, research programs at the DoE national laboratories, and the operation of major national user facilities. In keeping with the focus of the 1999 Seville Interfaces Workshop on Ceramic and Bimaterial Interfaces, this paper focuses on that portion of the Division's program devoted to interfaces in ceramic/ceramic, ceramic/metal and metal/metal systems. Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 US DOE, Off Basic Energy Sci, Div Mat Sci, Germantown, MD 20874 USA. RP Dragoo, AL (reprint author), US DOE, Off Basic Energy Sci, Div Mat Sci, Germantown, MD 20874 USA. EM Alan.dragoo@science.doe.gov NR 23 TC 1 Z9 1 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD DEC 1 PY 2000 VL 48 IS 18-19 BP 4629 EP 4633 DI 10.1016/S1359-6454(00)00249-4 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 381DL UT WOS:000165747000028 ER PT J AU Zurek, WH Bettencourt, LMA Dziarmaga, J Antunes, ND AF Zurek, WH Bettencourt, LMA Dziarmaga, J Antunes, ND TI Shards of broken symmetry: Topological defects as traces of the phase transition dynamics SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XLth Cracow School of Theoretical Physics CY JUN 03-11, 2000 CL ZAKOPANE, POLAND ID SCALAR FIELD-THEORY; STRING FORMATION; COSMOLOGICAL EXPERIMENTS; VORTEX FORMATION; SUPERFLUID HE-3; LIQUID-CRYSTALS; COSMIC STRINGS; EARLY UNIVERSE; QUENCH; VORTICES AB We discuss the origin of topological defects in phase transitions and analyze their role as a "diagnostic tool" in the study of the non-equilibrium dynamics of symmetry breaking. Homogeneous second order phase transitions are the focus of our attention, but the same paradigm is applied to the cross-over and inhomogeneous transitions. The discrepancy between the experimental results in He-3 and He-4 is discussed in the light of recent numerical studies. The possible role of the Ginzburg regime in determining the vortex line density for the case of a quench in He-4 is raised and tentatively dismissed. The difference in the anticipated origin of the dominant signal in the two (He-3 and He-4) cases is pointed out and the resulting consequences for the subsequent decay of vorticity are noted. The possibility of a significant discrepancy between the effective field theory and (quantum) kinetic theory descriptions of the order parameter is briefly touched upon, using atomic Bose-Einstein condensates as an example. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Geneva, Dept Phys Theor, CH-1211 Geneva 4, Switzerland. RP Zurek, WH (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 45 TC 10 Z9 10 U1 1 U2 2 PU ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS PI KRAKOW PA REYMONTA 4, 30-059 KRAKOW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD DEC PY 2000 VL 31 IS 12 BP 2937 EP 2962 PG 26 WC Physics, Multidisciplinary SC Physics GA 400DE UT WOS:000166855700008 ER PT J AU Dalvit, DAR Dziarmaga, J Zurek, WH AF Dalvit, DAR Dziarmaga, J Zurek, WH TI Decoherence and long-lived Schrodinger cats in BEC SO ACTA PHYSICA POLONICA B LA English DT Article; Proceedings Paper CT XLth Cracow School of Theoretical Physics CY JUN 03-11, 2000 CL ZAKOPANE, POLAND ID BOSE-EINSTEIN CONDENSATE; QUANTUM SUPERPOSITIONS; GROUND-STATE; ENTANGLEMENT; DYNAMICS; PHASE AB We consider quantum superposition states in Bose-Einstein condensates. A decoherence rate for the Schrodinger cat is calculated and shown to be a significant threat to this macroscopic quantum superposition of BEC's. An experimental scenario is outlined where the decoherence rate due to the thermal cloud is dramatically reduced thanks to trap engineering and "symmetrization" of the environment. We show that under the proposed scenario the Schrodinger cat belongs to an approximate decoherence-free pointer subspace. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Jagiellonian Univ, Inst Phys, PL-30059 Krakow, Poland. RP Dalvit, DAR (reprint author), Los Alamos Natl Lab, Div Theoret, T-6,MS-B288, Los Alamos, NM 87545 USA. NR 34 TC 2 Z9 2 U1 0 U2 0 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, PL-02-668 WARSAW, POLAND SN 0587-4254 J9 ACTA PHYS POL B JI Acta Phys. Pol. B PD DEC PY 2000 VL 31 IS 12 BP 3065 EP 3078 PG 14 WC Physics, Multidisciplinary SC Physics GA 400DE UT WOS:000166855700014 ER PT J AU Sambasivan, S Fischer, DA DeKoven, BM Kuperman, A AF Sambasivan, S Fischer, DA DeKoven, BM Kuperman, A TI Direct observations of propylene and silver transformations on the surface and in the pores of silver Y zeolites SO ADVANCED MATERIALS LA English DT Article ID TEMPERATURE-PROGRAMMED DESORPTION; SHELL EXCITATION-SPECTRA; CLUSTERS; ACIDITY; ATOMS; OXIDATION; REDUCTION; AG(110); STATE; NMR C1 Dow Chem Co, Midland, MI 48674 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Dow Chem Co USA, Sci Analyt Lab, Midland, MI 48667 USA. RP Kuperman, A (reprint author), Chevron Res & Technol Co, 100 Chevron Way, Richmond, CA 94802 USA. NR 34 TC 5 Z9 5 U1 0 U2 4 PU WILEY-V C H VERLAG GMBH PI BERLIN PA PO BOX 10 11 61, D-69451 BERLIN, GERMANY SN 0935-9648 J9 ADV MATER JI Adv. Mater. PD DEC 1 PY 2000 VL 12 IS 23 BP 1809 EP 1813 DI 10.1002/1521-4095(200012)12:23<1809::AID-ADMA1809>3.0.CO;2-B PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 390JK UT WOS:000166291800016 ER PT J AU Hammerand, DC Kapania, RK AF Hammerand, DC Kapania, RK TI Geometrically nonlinear shell element for hygrothermorheologically simple linear viscoelastic composites SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 40th Structures, Structural Dynamics, and Materials Conference CY APR 12-15, 1999 CL ST LOUIS, MISSOURI SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID LAMINATED PLATES; THERMOVISCOELASTIC ANALYSIS; TRIANGULAR ELEMENT; INITIAL DEFLECTION; COMPRESSION; PARAMETERS; ROTATIONS AB A triangular flat shell, element for large deformation analysis of linear viscoelastic laminated composites is presented. Hygrothermorheologically simple materials are considered for which a change in the hygrothermal environment results in a horizontal shifting of the relaxation moduli curves on a log timescale, in addition to the usual hygrothermal loads. Recurrence relations are developed and implemented for the evaluation of the viscoelastic memory loads. The nonlinear deformation process is computed using an incremental/iterative approach with the Newton-Raphson method used to find the incremental displacements in each time step. The presented numerical examples consider the large deformation and stability of linear viscoelastic structures under deformation-independent mechanical loads, deformation-dependent pressure loads, and thermal loads. Unlike elastic structures that have a single critical load value associated with a given snapping or buckling instability phenomenon, viscoelastic structures will usually exhibit a particular instability for a range of applied loads over a range of critical times. Both creep buckling and snap through examples are presented here. In some cases, viscoelastic results are also obtained using the quasi-elastic method in which load-history effects are ignored, and time-varying viscoelastic properties are simply used in a series of elastic problems. The presented numerical examples demonstrate the capability and accuracy of the formulation. C1 Virginia Polytech Inst & State Univ, Dept Aerosp & Ocean Engn, Blacksburg, VA 24061 USA. RP Hammerand, DC (reprint author), Sandia Natl Labs, Mat Mech Dept, POB 5800,MS-0847, Albuquerque, NM 87185 USA. NR 63 TC 6 Z9 6 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD DEC PY 2000 VL 38 IS 12 BP 2305 EP 2319 DI 10.2514/2.900 PG 15 WC Engineering, Aerospace SC Engineering GA 378CY UT WOS:000165568500014 ER PT J AU Jiang, JW Prausnitz, JM AF Jiang, JW Prausnitz, JM TI Phase equilibria for chain-fluid mixtures near to and far from the critical region SO AICHE JOURNAL LA English DT Review ID EQUATION-OF-STATE; VAPOR-LIQUID-EQUILIBRIA; RENORMALIZATION-GROUP THEORY; NATURAL-GAS SYSTEMS; ORNSTEIN-ZERNIKE EQUATION; HEAVY NORMAL PARAFFINS; LENNARD-JONES FLUID; N-ALKANE MIXTURES; SAFT-VR APPROACH; BINARY-MIXTURES AB A recently established crossover equation of state for pure chain fluids is extended to chain-fluid mixtures. Far from the critical region, where density fluctuations are small, it reduces to the classic equation of state. Near or at the critical point, the crossover equation of state incorporates contributions form long-wavelength density fluctuations. Using segment - segment parameters for pure components and one cross parameter k(12) for every binary pair as obtained from vapor - liquid equilibrium data remote from the critical region, this crossover equation of state glues vapor-liquid equilibria in good agreement with experiment for binary asymmetric mixtures of n-alkanes far from near to, and at the critical point. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI JIANG, Jianwen/G-1505-2013; OI Jiang, Jianwen/0000-0003-1310-9024 NR 136 TC 31 Z9 31 U1 1 U2 5 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0001-1541 J9 AICHE J JI AICHE J. PD DEC PY 2000 VL 46 IS 12 BP 2525 EP 2536 DI 10.1002/aic.690461219 PG 12 WC Engineering, Chemical SC Engineering GA 383DW UT WOS:000165868700018 ER PT J AU Mann, L Tolbert, V AF Mann, L Tolbert, V TI Soil sustainability in renewable biomass plantings SO AMBIO LA English DT Article ID SHORT-ROTATION FORESTRY; CARBON SEQUESTRATION; ENERGY-PRODUCTION; CROPPING SYSTEMS; HERBACEOUS CROPS; ORGANIC-MATTER; UNITED-STATES; WOODY CROPS; QUALITY; EROSION AB Sustainable use of natural resources continues to gain attention, especially in relation to energy and global carbon cycles. Biomass crops may offset fossil fuels and reduce CO2 contributions to greenhouse gases while improving soil and water quality. We review research on biomass crops, with emphasis on their specific characteristics and how their production can affect soil and water quality. Data from regions throughout the world are included, but the focus is primarily on recent research results from biomass crop production in the United States. Research to date shows promising short-term changes in soil and water quality, but responses vary. Short-term studies have demonstrated increases in surface soil organic-matter content, reduction in erosion and nutrient losses in surface runoff. We conclude that while the potential for benefits is present, data are not yet available to determine the long-term changes in soil quality associated with production of biomass crops. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Mann, L (reprint author), Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. NR 43 TC 41 Z9 46 U1 3 U2 18 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0044-7447 J9 AMBIO JI Ambio PD DEC PY 2000 VL 29 IS 8 BP 492 EP 498 DI 10.1639/0044-7447(2000)029[0492:SSIRBP]2.0.CO;2 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 400HL UT WOS:000166866100005 ER PT J AU Hauswaldt, JS Glenn, TC AF Hauswaldt, JS Glenn, TC TI Population genetic structure of the diamondback terrapin, Malaclemys terrapin centrata, using microsatellite DNA markers. SO AMERICAN ZOOLOGIST LA English DT Meeting Abstract C1 Univ S Carolina, Columbia, SC 29208 USA. Savannah River Ecol Lab, Aiken, SC USA. RI Glenn, Travis/A-2390-2008 NR 0 TC 0 Z9 0 U1 0 U2 4 PU AMER SOC ZOOLOGISTS PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0003-1569 J9 AM ZOOL JI Am. Zool. PD DEC PY 2000 VL 40 IS 6 BP 1048 EP 1049 PG 2 WC Zoology SC Zoology GA 422RA UT WOS:000168132000325 ER PT J AU Xu, J Whitten, WB Ramsey, JM AF Xu, J Whitten, WB Ramsey, JM TI Space charge effects on resolution in a miniature ion mobility spectrometer SO ANALYTICAL CHEMISTRY LA English DT Article ID MULTI-PHOTON IONIZATION; PLASMA CHROMATOGRAPHY; ANALYTICAL-CHEMISTRY; MASS-SPECTROMETRY AB Miniaturization of ion mobility spectrometry (IMS) is expected to have many advantages, as well as difficulties, in the separation of chemical species at atmospheric pressure. We report the results of studies of a miniature ion mobility spectrometer that has a drift channel 1.7 mm in diameter, the smallest cross section reported to date. The miniature cell contains a homogeneous drift field and is operated at atmospheric pressure. The miniature IMS has been characterized by measuring both negative and positive ion spectra using a frequency-quadrupled Nd: YAG laser on samples of NO, O-2, and methyl iodide; a useful resolution (>10) was achieved with an operating voltage of 500 V. Peak broadening due to Coulomb repulsion was determined to have a major effect on the resolution of the miniature device. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Whitten, WB (reprint author), Oak Ridge Natl Lab, POB 2008,MS 6142, Oak Ridge, TN 37831 USA. NR 19 TC 38 Z9 41 U1 3 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD DEC 1 PY 2000 VL 72 IS 23 BP 5787 EP 5791 DI 10.1021/ac0005464 PG 5 WC Chemistry, Analytical SC Chemistry GA 378MA UT WOS:000165587100018 PM 11128937 ER PT J AU Culbertson, CT Jacobson, SC Ramsey, JM AF Culbertson, CT Jacobson, SC Ramsey, JM TI Microchip devices for high-efficiency separations SO ANALYTICAL CHEMISTRY LA English DT Article ID MICELLAR ELECTROKINETIC CHROMATOGRAPHY; CAPILLARY ELECTROPHORESIS; LIQUID-CHROMATOGRAPHY; CHIPS AB We have fabricated a 25-cm-long spiral-shaped separation channel on a glass microchip with a footprint of only 5 cm x 5 cm. Electrophoretic separation efficiencies for dichlorofluoroscein (DCF) on this chip exceeded 1 000 000 theoretical plates and were achieved in under 46 s at a detection point 22.2 cm from the injection cross. The number of theoretical plates increased linearly with the applied voltage, and at a separation field strength of 1170 V/cm, the rate of plate generation was similar to 21 000 plates/s. The large radii of curvature of the turns minimized the analyte dispersion introduced by the channel geometry as evidenced by the fact that the effective diffusion coefficient of DCF was within a few percent of that measured on a microchip with a straight separation channel over a wide range of electric field strengths. A micellar electrokinetic chromatography separation of 19 tetramethylrhodamine-labeled amino acids was accomplished in 165 s with an average plate number of 280 000. The minimum resolution between adjacent peaks for this separation was 1.2. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ramsey, JM (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. OI Culbertson, Christopher/0000-0002-6833-3237 NR 26 TC 182 Z9 186 U1 4 U2 30 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD DEC 1 PY 2000 VL 72 IS 23 BP 5814 EP 5819 DI 10.1021/ac0006268 PG 6 WC Chemistry, Analytical SC Chemistry GA 378MA UT WOS:000165587100022 PM 11128941 ER PT J AU Magnuson, JK Romine, MF Burris, DR Kingsley, MT AF Magnuson, JK Romine, MF Burris, DR Kingsley, MT TI Trichloroethene reductive dehalogenase from Dehalococcoides ethenogenes: Sequence of tceA and substrate range characterization SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID STRICTLY ANAEROBIC BACTERIUM; DEHALOSPIRILLUM MULTIVORANS; SP-NOV; DECHLORINATES TETRACHLOROETHENE; DESULFITOBACTERIUM DEHALOGENANS; GEN-NOV; PROTEINS; PURIFICATION; OXIDATION; ETHENE AB The anaerobic bacterium Dehalococcoides ethenogenes is the only known organism that can completely dechlorinate tetrachloroethene or trichloroethene (TCE) to ethene via dehalorespiration. One of two corrinoid-containing enzymes responsible for this pathway, TCE reductive dehalogenase (TCE-RDase) catalyzes the dechlorination of TCE to ethene. TCE-RDase dehalogenated 1,2-dichloroethane and 1,2-dibromoethane to ethene at rates of 7.5 and 30 mu mol/min/mg, respectively, similar to the rates for TCE, cis-dichloroethene (DCE), and 1,1-DCE. A variety of other haloalkanes and haloalkenes containing three to five carbon atoms were dehalogenated at lower rates. The gene encoding TCE-RDase, tceA, was cloned and sequenced via an inverse PCR approach. Sequence comparisons of tceA to proteins in the public databases revealed weak sequence similarity confined to the C-terminal region, which contains the eight-iron ferredoxin cluster binding motif, (CXXCXXCXXXCP)(2). Direct N-terminal sequencing of the mature enzyme indicated that the first 42 amino acids constitute a signal sequence containing the twin-arginine motif, RRXFXK, associated with the Sec-independent membrane translocation system. This information coupled with membrane localization studies indicated that TCE-RDase is located on the exterior of the cytoplasmic membrane. Like the case for the two other RDases that have been cloned and sequenced, a small open reading frame, tceB, is proposed to be involved with membrane association of TCE-RDase and is predicted to be cotranscribed with tceA. C1 Pacific NW Natl Lab, MSIN, Richland, WA 99352 USA. USAF, Res Lab, Tyndall AFB, FL 32403 USA. RP Magnuson, JK (reprint author), Pacific NW Natl Lab, MSIN, K2-21,902 Battelle Blvd,POB 999, Richland, WA 99352 USA. NR 34 TC 179 Z9 180 U1 7 U2 52 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD DEC PY 2000 VL 66 IS 12 BP 5141 EP 5147 DI 10.1128/AEM.66.12.5141-5147.2000 PG 7 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 404QP UT WOS:000167112400007 PM 11097881 ER PT J AU Davey, ME de Bruijn, FJ AF Davey, ME de Bruijn, FJ TI A homologue of the tryptophan-rich sensory protein TspO and FixL regulate a novel nutrient deprivation-induced Sinorhizobium meliloti locus SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID RHIZOBIUM-MELILOTI; ESCHERICHIA-COLI; STATIONARY-PHASE; BENZODIAZEPINE RECEPTOR; NITROGEN-FIXATION; STRESS-RESPONSE; INDUCIBLE GENES; STARVATION; SURVIVAL; IDENTIFICATION AB A nutrient deprivation-induced locus in Sinorhizobium meliloti strain 1021 was identified by use of a Tn5-luxAB reporter gene transposon, The tagged locus is comprised of two open reading frames (ORFs) designated ndiA and ndiB for nutrient deprivation-induced genes A and B. Comparison of the deduced amino acid sequences of both ndiA and ndiB to the protein databases failed to reveal similarity to any known genes. The expression of the ndi locus was found to be induced by carbon and nitrogen deprivation, osmotic stress, and oxygen limitation and during entry into stationary phase. To identify regulatory components involved in the control of ndi gene expression, a second round of mutagenesis was performed on the primary ndiB::Tn5-lunAB-tagged strain (C22) with transposon Tn1721, A double-mutant strain was obtained that lacked ndi locus transcriptional activity under ail of the inducing conditions tested. The Tn1721-tagged gene showed a high degree of similarity to tryptophan-rich sensory protein TspO from Rhodobacter sphaeroides, as well as to mitochondrial benzodiazepine receptor pK18 from mammals. Induction of the ndi::Tn5-luxAB reporter gene fusion was restored under all inducing conditions by introducing the tspO coding region, from either S, meliloti or R sphaeroides, in trans. Furthermore, it was found that, in addition to tspO,fixL, which encodes the sensor protein of an oxygen-sensing two-component system, is required for full expression of the ndi locus, but only under low oxygen tension. C1 MSU, US DOE, NSF, Ctr Microbial Ecol,Plant Res Lab, E Lansing, MI 48824 USA. Michigan State Univ, Dept Microbiol, E Lansing, MI 48824 USA. RP Davey, ME (reprint author), Dartmouth Med Sch, Dept Microbiol, Vail Bldg,Rm 202, Hanover, NH 03755 USA. NR 59 TC 37 Z9 39 U1 0 U2 3 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD DEC PY 2000 VL 66 IS 12 BP 5353 EP 5359 DI 10.1128/AEM.66.12.5353-5359.2000 PG 7 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 404QP UT WOS:000167112400040 PM 11097914 ER PT J AU Beller, HR Edwards, EA AF Beller, HR Edwards, EA TI Anaerobic toluene activation by benzylsuccinate synthase in a highly enriched methanogenic culture SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SP STRAIN-T; THAUERA-AROMATICA; INITIAL REACTIONS; O-XYLENE; OXIDATION; DEGRADATION; BACTERIUM; MINERALIZATION; METABOLITES; CONSORTIUM AB Permeabilized cells of a highly enriched, toluene-mineralizing, methanogenic culture catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. The specific in vitro rate of benzylsuccinate formation was >85% of the specific in vivo rate of toluene consumption, This is the first report of benzylsuccinate synthase activity in a methanogenic culture; the activity has previously been reported to occur in denitrifying, sulfate-reducing, and anoxygenic phototrophic bacteria. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Toronto, Dept Chem Engn & Appl Chem, Toronto, ON M5S 3E5, Canada. RP Beller, HR (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-542, Livermore, CA 94551 USA. RI Beller, Harry/H-6973-2014; OI Edwards, Elizabeth/0000-0002-8071-338X NR 20 TC 51 Z9 52 U1 1 U2 13 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD DEC PY 2000 VL 66 IS 12 BP 5503 EP 5505 DI 10.1128/AEM.66.12.5503-5505.2000 PG 3 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 404QP UT WOS:000167112400063 PM 11097937 ER PT J AU Hendrickson, B AF Hendrickson, B TI Load balancing fictions, falsehoods and fallacies SO APPLIED MATHEMATICAL MODELLING LA English DT Article DE load balancing; graph partitioning; parallel computer ID DOMAIN DECOMPOSITION; ASPECT RATIO; PARALLEL AB Effective use of a parallel computer requires that a calculation be carefully divided among the processors. This load balancing problem appears in many guises and has been a fervent area of research for the past decade or more. Although great progress has been made, and useful software tools developed, a number of challenges remain. It is the conviction of the author that these challenges will be easier to address if we first come to terms with some significant shortcomings in our current perspectives. This paper tries to identify several areas in which the prevailing point of view is either mistaken or insufficient. The goal is to motivate new ideas and directions for this important field. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Sandia Natl Labs, Parallel Comp Sci Dept, Albuquerque, NM 87185 USA. RP Hendrickson, B (reprint author), Sandia Natl Labs, Parallel Comp Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 28 TC 20 Z9 20 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0307-904X J9 APPL MATH MODEL JI Appl. Math. Model. PD DEC PY 2000 VL 25 IS 2 BP 99 EP 108 DI 10.1016/S0307-904X(00)00042-1 PG 10 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 390PZ UT WOS:000166306700003 ER PT J AU Biswas, R Das, SK Harvey, DJ Oliker, L AF Biswas, R Das, SK Harvey, DJ Oliker, L TI Parallel dynamic load balancing strategies for adaptive irregular applications SO APPLIED MATHEMATICAL MODELLING LA English DT Article DE unstructured mesh adaptation; global dynamic load balancing; symmetric broadcast networks; parallel computing ID UNSTRUCTURED MESHES; COMPUTERS AB Dynamic unstructured mesh adaptation is a powerful technique for solving computational problems with evolving physical features; however, an efficient parallel implementation is rather difficult because of the load imbalance that mesh adaptation creates. To address this problem, we have developed two dynamic load balancing strategies for parallel adaptive irregular applications. The first, called PLUM, is an architecture-independent framework particularly geared toward adaptive numerical computations and requires that all data be globally redistributed after each adaptation to achieve load balance. The second is a more general-purpose topology-independent load balancer that utilizes symmetric broadcast networks (SBN) as the underlying communication pattern, with a goal to providing a global view of system loads across processors. Results indicate that both PLUM and the SBN-based approach have their relative merits, and that they achieve excellent load balance at the cost of minimal extra overhead. (C) 2000 Elsevier Science Inc. All rights reserved. C1 NASA, Ames Res Ctr, Comp Sci Corp, Moffett Field, CA 94035 USA. Univ Texas, Dept Comp Sci & Engn, Arlington, TX 76019 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Biswas, R (reprint author), NASA, Ames Res Ctr, Comp Sci Corp, Mail Stop T27 A-1, Moffett Field, CA 94035 USA. EM rbiswas@nas.nasa.gov; das@cse.uta.edu; harvey@cse.uta.edu; loliker@lbl.gov NR 30 TC 3 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0307-904X EI 1872-8480 J9 APPL MATH MODEL JI Appl. Math. Model. PD DEC PY 2000 VL 25 IS 2 BP 109 EP 122 DI 10.1016/S0307-904X(00)00040-8 PG 14 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Engineering; Mathematics; Mechanics GA 390PZ UT WOS:000166306700004 ER PT J AU Canpolat, M Mourant, JR AF Canpolat, M Mourant, JR TI Monitoring photosensitizer concentration by use of a fiber-optic probe with a small source-detector separation SO APPLIED OPTICS LA English DT Article ID OPTIMIZING LIGHT DOSIMETRY; IN-VIVO MEASUREMENTS; FLUORESCENCE SPECTROSCOPY; PHOTODYNAMIC THERAPY; TURBID MEDIA; INTRINSIC FLUORESCENCE; TISSUE; SCATTERING; MODEL; SPECTRA AB We present a noninvasive method to track the concentration of photodynamic therapy drugs in real time. The method is based on measurements of backscattered and fluorescent light with a steady-state fluorescence spectrometer. The ratio of the fluorescent light to the scattered light is found to be linearly proportional to the absorption coefficient of the photosensitizer. The fiber-optic probe used for the measurements has a small source-detector separation; therefore the measurements could be performed through the working channel of an endoscope. (C) 2000 Optical Society of America OCIS codes: 170.3890, 170.5180. C1 Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. RP Canpolat, M (reprint author), Imaging Diagnost Syst Inc, 6531 NW 18th Court, Plantation, FL 33313 USA. EM jmourant@lanl.gov NR 20 TC 26 Z9 26 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD DEC 1 PY 2000 VL 39 IS 34 BP 6508 EP 6514 DI 10.1364/AO.39.006508 PG 7 WC Optics SC Optics GA 378WC UT WOS:000165607300030 PM 18354664 ER PT J AU Fujita, E Chou, M Tanaka, K AF Fujita, E Chou, M Tanaka, K TI Characterization of Ru(bpy)(2)(CO)(COO) prepared by CO2 addition to Ru(bpy)(2)(CO) in acetonitrile SO APPLIED ORGANOMETALLIC CHEMISTRY LA English DT Article; Proceedings Paper CT 5th International Conference on Carbon Dioxide Utilization (ICCDU V) CY SEP 05-10, 1999 CL KARLSRUHE, GERMANY DE carboxylates; carbon dioxide reduction; photocatalysis; small molecule activation; ruthenium ID ELECTROCATALYTIC REDUCTION; CRYSTAL-STRUCTURE; 2+; BPY=2,2'-BIPYRIDINE; WATER; HCOO AB A,carboxylate complex, [Ru(bpy)(2)(CO)(COO)], was prepared by the addition of CO2 to the doubly reduced species, [Ru-I(bpy)(bpy(-.))(CO)], in CH3CN. The IR and UV-vis spectra of [Ru(bpy)(2)(CO)(COO)] show a marked cation and solvent dependence. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Inst Mol Sci, Okazaki, Aichi 4448585, Japan. RP Fujita, E (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RI Fujita, Etsuko/D-8814-2013 NR 15 TC 11 Z9 11 U1 0 U2 9 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0268-2605 J9 APPL ORGANOMET CHEM JI Appl. Organomet. Chem. PD DEC PY 2000 VL 14 IS 12 SI SI BP 844 EP 846 DI 10.1002/1099-0739(200012)14:12<844::AID-AOC76>3.3.CO;2-7 PG 3 WC Chemistry, Applied; Chemistry, Inorganic & Nuclear SC Chemistry GA 380KG UT WOS:000165700600018 ER PT J AU DuBois, DL Berning, DE AF DuBois, DL Berning, DE TI Hydricity of transition-metal hydrides and its role in CO2 reduction SO APPLIED ORGANOMETALLIC CHEMISTRY LA English DT Article; Proceedings Paper CT 5th International Conference on Carbon Dioxide Utilization (ICCDU V) CY SEP 05-10, 1999 CL KARLSRUHE, GERMANY DE transition metal hydrides; CO2 reduction ID COMPLEXES AB The role of C-H bond formation in the reduction of carbon dioxide, mediated by metal and palladium phosphine catalysts is studied, Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP DuBois, DL (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 9 TC 41 Z9 41 U1 1 U2 19 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0268-2605 J9 APPL ORGANOMET CHEM JI Appl. Organomet. Chem. PD DEC PY 2000 VL 14 IS 12 SI SI BP 860 EP 862 DI 10.1002/1099-0739(200012)14:12<860::AID-AOC87>3.0.CO;2-A PG 3 WC Chemistry, Applied; Chemistry, Inorganic & Nuclear SC Chemistry GA 380KG UT WOS:000165700600023 ER PT J AU Salleo, A Sands, T Genin, FY AF Salleo, A Sands, T Genin, FY TI Machining of transparent materials using an IR and UV nanosecond pulsed laser SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article ID EXCIMER-LASER; FUSED-SILICA; BULK DAMAGE; ABLATION; RADIATION; GLASSES; DIELECTRICS; FEMTOSECOND; PICOSECOND; CRACKS AB Channels are traditionally machined in materials by drilling from the front side into the bulk. The processing rate can be increased by two orders of magnitude for transparent materials by growing the channel from the rear side. The process is demonstrated using nanosecond laser pulses to drill millimeter-sized channels through thick silica windows. Absorbing defects are introduced onto the rear surface to initiate the coupling of energy into the material. Laser drilling then takes place when the fluence exceeds a threshold. The drilling late increases linearly with fluence above this threshold. While UV light drills about four times faster than TR light, the pulse length (in the nanosecond regime) and the pulse repetition rate (in the 0. 1-10 Hz range) do not greatly influence the drilling rate per pulse. Drilling rates in excess of 100 mum per pulse are achieved by taking advantage of the propagation characteristics of the plasma created at the drilling front. The plasma during rearside drilling generates a laser-supported detonation wave into the bulk material. The geometry also seems to increase the efficiency of the laser-induced plasma combustion and shock wave during the pulse by confining it in front of the channel tip. C1 Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Salleo, A (reprint author), Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RI Sands, Timothy/D-2133-2009 OI Sands, Timothy/0000-0001-9718-6515 NR 44 TC 41 Z9 44 U1 0 U2 19 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 2000 VL 71 IS 6 BP 601 EP 608 DI 10.1007/s003390000546 PG 8 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 401JQ UT WOS:000166924800001 ER PT J AU Armitage, R Cich, M Rubin, M Weber, ER AF Armitage, R Cich, M Rubin, M Weber, ER TI A method to pattern Pd over-layers on GdMg films and its application to increase the transmittance of metal hydride optical switches SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Article ID HYDROGEN INSERTION AB A process to pattern Pd over-layers on reactive metal films was developed using ion milling through a tungsten trioxide mask patterned by photolithography and wet etching. The WO3 mask exhibited a low Ar+ sputter yield and, unlike conventional mask materials (SiO2, Si3N4), was easily etched in a mild alkaline solution. This procedure was applied to convert a 20-nm fd cap over a 160-nm GdMg film to a Pd grid with approximate to 9-mum-diameter openings covering approximate to 40% of the surface. The Pd grid proved sufficient to catalyze the (de)hydriding reactions required to reversibly switch the GdMg film from reflecting to transparent. The maximum transmittance of the patterned Pd/GdMg hydride bi-layer was twice that of an otherwise identical sample with a continuous Pd cap, with similar hydriding kinetics. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Armitage, R (reprint author), Univ Calif Berkeley, Dept Mat Sci & Engn, Mail Code 1760, Berkeley, CA 94720 USA. NR 12 TC 4 Z9 5 U1 0 U2 1 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD DEC PY 2000 VL 71 IS 6 BP 647 EP 650 DI 10.1007/s003390000582 PG 4 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 401JQ UT WOS:000166924800009 ER PT J AU Volkan, M Stokes, DL Vo-Dinh, T AF Volkan, M Stokes, DL Vo-Dinh, T TI Surface-enhanced Raman of dopamine and neurotransmitters using sol-gel substrates and polymer-coated fiber-optic probes SO APPLIED SPECTROSCOPY LA English DT Article DE dopamine determination; SERS; neurotransmitters; fiber-optic probe; sol-gel ID RESONANCE RAMAN; ASCORBIC-ACID; ELECTROCHEMICAL DETECTION; LIQUID-CHROMATOGRAPHY; SELECTIVE DETECTION; SPECTROSCOPY; SCATTERING; ELECTRODES; SILVER; METABOLITES AB Surface-enhanced Raman spectroscopy (SERS) is used to detect catecholamines-viz., dopamine, norepinephrine, epinine, and isoproterenol-using a new substrate prepared with sol-gel technology. Catecholamines are complexed at the surface by iron(III) ions, which were introduced during the reduction of the silver ions embedded inside the sol-gel matrix. With the use of a He-Ne laser at a power of only 12 mW, it is possible to measure dopamine in the micromolar concentration range. A single-fiber SERS probe system was also introduced that has great potential for sampling in micro-environment applications such as in vivo measurements of dopamine. In this microprobe design both excitation and SERS signals are transmitted through the same fiber simultaneously. The tips of tapered fibers were coated with a polyvinyl alcohol polymer doped with metallic silver particles. The potential of the SERS method and microprobes for medical diagnostics is discussed. C1 Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. Middle E Tech Univ, Fac Art & Sci, Dept Chem, TR-06531 Ankara, Turkey. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. NR 40 TC 44 Z9 44 U1 8 U2 58 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 5320 SPECTRUM DRIVE SUITE C, FREDERICK, MD 21703 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD DEC PY 2000 VL 54 IS 12 BP 1842 EP 1848 DI 10.1366/0003702001948952 PG 7 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 388NX UT WOS:000166188600017 ER PT J AU Wadkins, RM Tung, CS Vallone, PM Benight, AS AF Wadkins, RM Tung, CS Vallone, PM Benight, AS TI The role of the loop in binding of an actinomycin D analog to hairpins formed by single-stranded DNA SO ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS LA English DT Article DE drug-DNA interactions; HIV reverse transcriptase; transcription; DNA secondary structure ID ACID MODELING TOOL; REVERSE-TRANSCRIPTASE; NUCLEIC-ACIDS; DRUG; SEQUENCE; 7-AMINO-ACTINOMYCIN-D; INHIBITION; PROBE AB Our recent work has indicated that the potent antibiotic and antitumor agent actinomycin D has the ability to selectively bind and stabilize single-stranded DNA that is capable of adopting a hairpin conformation. This mechanism of DNA binding has been implicated in the drug's ability to inhibit transcription by HIV reverse transcriptase from single-stranded DNA templates. In this report, we studied the importance of the hairpin loop on the ability of the 7-amino analog of actinomycin D to selectively bind DNA hairpins. Binding dissociation constant (K-d) values were determined to be 0.22 +/- 0.11 muM for the hairpin formed from the single-stranded DNA 5'-AAAAAAATAGTTTTAAATATTTTTTT-3' (dubbed HP1). The hairpin stem without the loop resulted in binding with K-d = 2.6 +/- 0.9 muM. The drug showed low affinity for the HP1 strand fully duplexed to its complementary sequence (estimated to be at least K-d > 21 muM). Evaluation of 7-aminoactinomycin D binding to a library of thermodynamically characterized DNA hairpins revealed an affinity for the hairpin-forming sequence 5'-GGATACCCCCGTATCC-3' (dubbed ACC4) of K-d = 6.8 +/- 2.2 muM. Replacement of the terminal guanines of this sequence to generate 5'-ATATACCCCCGTATAT-3' resulted in a 10-fold increase in affinity for this hairpin compared to ACC4, to K-d = 0.74 +/- 0.06 muM. A molecular model of the ACC4-actinomycin D complex reveals that significant interactions between the hairpin loop and the pentapeptide rings of the drug must occur during drug binding. Taken together, our data indicate that the composition of the stem-loop interface is critical for the selectivity of actinomycin D and its 7-amino analog for DNA hairpins and suggests that novel drugs may be designed based on selection for the desired hairpin composition. (C) 2000 Academic Press. C1 Johns Hopkins Univ, Sch Med, Dept Oncol, Baltimore, MD 21231 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Illinois, Dept Chem, Chicago, IL 60617 USA. RP Wadkins, RM (reprint author), Johns Hopkins Univ, Sch Med, Dept Oncol, Bunting Blaustein Bldg Canc Res,Room 1M90,1650 Or, Baltimore, MD 21231 USA. NR 26 TC 22 Z9 26 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0003-9861 J9 ARCH BIOCHEM BIOPHYS JI Arch. Biochem. Biophys. PD DEC 1 PY 2000 VL 384 IS 1 BP 199 EP 203 DI 10.1006/abbi.2000.2113 PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 380JF UT WOS:000165697500023 PM 11147831 ER PT J AU Cupal, J Kopp, S Stadler, PF AF Cupal, J Kopp, S Stadler, PF TI RNA shape space topology SO ARTIFICIAL LIFE LA English DT Article; Proceedings Paper CT 6th International Conference on the Simulation and Synthesis of Living Systems CY 1998 CL UNIV CALIF, LOS ANGELES, CA SP Univ Calif HO UNIV CALIF DE genotype-phenotype map; RNA folding; finite topological space; continuity in evolution ID SEQUENCE STRUCTURE MAPS; SECONDARY STRUCTURES; NEUTRAL NETWORKS; EXHAUSTIVE ENUMERATION; PREDICTIONS; ADAPTATION; STATISTICS; EVOLUTION AB The distinction between continuous and discontinuous transitions is a long-standing problem in the theory of evolution. Because continuity is a topological property, we present a formalism that treats the space of phenotypes as a (finite) topological space, with a topology that is derived from the probabilities with which one phenotype is accessible From another through changes at the genotypic level. The shape space of RNA secondary structures is used to illustrate this approach. We show that evolutionary trajectories are continuous if and only if they follow connected paths in phenotype space. C1 Univ Vienna, Inst Theoret Chem, A-1090 Vienna, Austria. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Santa Fe Inst, Santa Fe, NM 87501 USA. RP Stadler, PF (reprint author), Univ Vienna, Inst Theoret Chem, Wahringerstr 17, A-1090 Vienna, Austria. EM studla@tbi.univie.ac.at RI Stadler, Peter F./L-7857-2015 OI Stadler, Peter F./0000-0002-5016-5191 NR 45 TC 14 Z9 14 U1 0 U2 0 PU MIT PRESS PI CAMBRIDGE PA ONE ROGERS ST, CAMBRIDGE, MA 02142-1209 USA SN 1064-5462 EI 1530-9185 J9 ARTIF LIFE JI Artif. Life PD WIN PY 2000 VL 6 IS 1 BP 3 EP 23 DI 10.1162/106454600568294 PG 21 WC Computer Science, Artificial Intelligence; Computer Science, Theory & Methods SC Computer Science GA 332YU UT WOS:000088102600002 PM 10943663 ER PT J AU Brambley, MR Chassin, DP Gowri, K Kammers, B Branson, DJ AF Brambley, MR Chassin, DP Gowri, K Kammers, B Branson, DJ TI DDC and the Web SO ASHRAE JOURNAL LA English DT Article C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Johnson Controls Inc, Bldg Management Syst, Milwaukee, WI USA. Compliance Serv Grp, Lubbock, TX USA. RP Brambley, MR (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 0001-2491 J9 ASHRAE J JI ASHRAE J. PD DEC PY 2000 VL 42 IS 12 BP 38 EP + PG 7 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 382FK UT WOS:000165812200008 ER PT J AU Coil, AL Matheson, T Filippenko, AV Leonard, DC Tonry, J Riess, AG Challis, P Clocchiatti, A Garnavich, PM Hogan, CJ Jha, S Kirshner, RP Leibundgut, B Phillips, MM Schmidt, BP Schommer, RA Smith, RC Soderberg, AM Spyromilio, J Stubbs, C Suntzeff, NB Woudt, P AF Coil, AL Matheson, T Filippenko, AV Leonard, DC Tonry, J Riess, AG Challis, P Clocchiatti, A Garnavich, PM Hogan, CJ Jha, S Kirshner, RP Leibundgut, B Phillips, MM Schmidt, BP Schommer, RA Smith, RC Soderberg, AM Spyromilio, J Stubbs, C Suntzeff, NB Woudt, P TI Optical spectra of Type Ia supernovae at z=0.46 and z=1.2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; supernovae : general; supernovae : individual (SN 1999ff, SN 1999fv) ID UNIVERSE; EVOLUTION; AGE AB We present optical spectra, obtained with the Keck 10 m telescope, of two high-redshift Type Ia supernovae (SNe Ia) discovered by the High-z Supernova Search Team: SN 1999ff at z = 0.455 and SN 1999fv at z similar to 1.2, the highest redshift published SN Ia spectrum. Both SNe were at maximum light when the spectra were taken. We compare our high-z spectra with low-z normal and peculiar SNe Ia as well as with SNe Ic, Ib, and II. There are no significant differences between SN 1999ff and normal SNe Ia at low redshift. SN 1999fv appears to be an SN Ia and does not resemble the most peculiar nearby SNe Ia. C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. European So Observ, D-85748 Garching, Germany. Univ Washington, Dept Astron, Seattle, WA 98195 USA. European So Observ, D-85748 Garching, Germany. Cerro Tololo Interamer Observ, La Serena, Chile. Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Coil, AL (reprint author), Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RI Stubbs, Christopher/C-2829-2012; OI Stubbs, Christopher/0000-0003-0347-1724; Schmidt, Brian/0000-0002-8538-9195 NR 32 TC 44 Z9 44 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2000 VL 544 IS 2 BP L111 EP L114 DI 10.1086/317311 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 384FC UT WOS:000165931300007 ER PT J AU Salmonson, JD AF Salmonson, JD TI On the kinematic origin of the luminosity-pulse lag relationship in gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; gamma rays : theory ID SPECTRAL EVOLUTION AB This Letter presents an interpretation based on gamma-ray burst source kinematics for the relationship found by Norris et al. between peak luminosity and energy-dependent pulse lag. I argue that the correlation should instead be between number luminosity and pulse lag. This interpretation improves the least-squares fit of this correlation for the known bursts by 25% or more. It also suggests a distance estimation scheme. I propose that this relationship is due to the variation in line-of-sight velocity among bursts. This interpretation allows one to speculate on the range of gamma-ray burst expansion velocities or the size of their jet opening angles. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Salmonson, JD (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA. NR 13 TC 53 Z9 54 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD DEC 1 PY 2000 VL 544 IS 2 BP L115 EP L117 DI 10.1086/317305 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 384FC UT WOS:000165931300008 ER PT J AU Sniegowski, PD Gerrish, PJ Johnson, T Shaver, A AF Sniegowski, PD Gerrish, PJ Johnson, T Shaver, A TI The evolution of mutation rates: separating causes from consequences SO BIOESSAYS LA English DT Review ID ESCHERICHIA-COLI; BENEFICIAL MUTATIONS; ASEXUAL POPULATIONS; ADAPTIVE EVOLUTION; DELETERIOUS MUTATIONS; SELECTION BALANCE; NATURAL-SELECTION; ADAPTATION; MUTATORS; BACTERIA AB Natural selection can adjust the rate of mutation in a population by acting on allelic variation affecting processes of DNA replication and repair. Because mutation is the ultimate source of the genetic variation required for adaptation, it can be appealing to suppose that the genomic mutation rate is adjusted to a level that best promotes adaptation. Most mutations with phenotypic effects are harmful, however, and thus there is relentless selection within populations for lower genomic mutation rates. Selection on beneficial mutations can counter this effect by favoring alleles that raise the mutation rate, but the effect of beneficial mutations on the genomic mutation rate is extremely sensitive to recombination and is unlikely to be important in sexual populations. In contrast, high genomic mutation rates can evolve in asexual populations under the influence of beneficial mutations, but this phenomenon is probably of limited adaptive significance and represents, at best, a temporary reprieve from the continual selection pressure to reduce mutation. The physiological cost of reducing mutation below the low level observed in most populations may be the most important factor in setting the genomic mutation rate in sexual and asexual systems, regardless of the benefits of mutation in producing new adaptive variation. Maintenance of mutation rates higher than the minimum set by this "cost of fidelity" is likely only under special circumstances. (C) 2000 John Wiley & Sons, Inc. C1 Univ Penn, Dept Biol, Philadelphia, PA 19104 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Edinburgh, Inst Cell Anim & Populat Biol, Edinburgh, Midlothian, Scotland. RP Sniegowski, PD (reprint author), Univ Penn, Dept Biol, Philadelphia, PA 19104 USA. EM paulsnie@sas.upenn.edu OI Gerrish, Philip/0000-0001-6393-0553; Johnson, Toby/0000-0002-5998-3270 NR 77 TC 261 Z9 268 U1 9 U2 75 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0265-9247 J9 BIOESSAYS JI Bioessays PD DEC PY 2000 VL 22 IS 12 BP 1057 EP 1066 DI 10.1002/1521-1878(200012)22:12<1057::AID-BIES3>3.0.CO;2-W PG 10 WC Biochemistry & Molecular Biology; Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics GA 377XX UT WOS:000165552500003 PM 11084621 ER PT J AU Xu, Y Xu, D Gambow, HN AF Xu, Y Xu, D Gambow, HN TI Protein domain decomposition using a graph-theoretic approach SO BIOINFORMATICS LA English DT Article ID FOLDING UNITS; STRUCTURAL DOMAINS; GLOBULAR-PROTEINS; IDENTIFICATION; CLASSIFICATION; IMPROVEMENTS; ORGANIZATION; ALGORITHM; DATABASE; NETWORK AB Motivation: Automatic decomposition of a multi-domain protein into individual domains represents a highly interesting and unsolved problem. As the number of protein structures in PDB is growing at an exponential rate, there is clearly a need for more reliable and efficient methods for protein domain decomposition simply to keep the domain databases up-to-date. Results: We present a new algorithm for solving the domain decomposition problem, using a graph-theoretic approach. We have formulated the problem as a network flow problem, in which each residue of a protein is represented as a node of the network and each residue-residue contact is represented as an edge with a particular capacity, depending on the type of the contact. A two-domain decomposition problem is solved by finding a bottleneck (or a minimum cut) of the network, which minimizes the total cross-edge capacity using the classical Ford-Fulkerson algorithm. A multi-domain decomposition problem is solved through repeatedly solving a series of two-domain problems. The algorithm has been implemented as a computer program, called DomainParser. We have tested the program on a commonly used test set consisting of 55 proteins. The decomposition results are 78.2% in agreement with the literature on both the number of decomposed domains and the assignments of residues to each domain, which compares favorably to existing programs. On the subset of two-domain proteins (20 in number), the program assigned 96.7% of the residues correctly when we require that the number of decomposed domains is two. C1 Oak Ridge Natl Lab, Div Life Sci, Computat Biosci Sect, Oak Ridge, TN 37830 USA. Univ Colorado, Dept Comp Sci, Boulder, CO 80309 USA. RP Xu, Y (reprint author), Oak Ridge Natl Lab, Div Life Sci, Computat Biosci Sect, Oak Ridge, TN 37830 USA. NR 37 TC 68 Z9 74 U1 1 U2 4 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD DEC PY 2000 VL 16 IS 12 BP 1091 EP 1104 DI 10.1093/bioinformatics/16.12.1091 PG 14 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 395ZE UT WOS:000166611200005 PM 11159328 ER PT J AU Schumaker, MF Pomes, R Roux, B AF Schumaker, MF Pomes, R Roux, B TI A combined molecular dynamics and diffusion model of single proton conduction through gramicidin SO BIOPHYSICAL JOURNAL LA English DT Article ID ION-CHANNEL; A CHANNELS; PERMEATION; WATER; FLEXIBILITY; TRANSPORT; MEMBRANE; ENERGY; WIRE; BULK AB We develop a model for proton conduction through gramicidin based on the molecular dynamics simulations of Pomes and Roux (Biophys. J. 72:A246, 1997). The transport of a single proton through the gramicidin pore is described by a potential of mean force and diffusion coefficient obtained from the molecular dynamics, In addition, the model incorporates the dynamics of a defect in the hydrogen bonding structure of pore waters without an excess proton. Proton entrance and exit were not simulated by the molecular dynamics. The single proton conduction model includes a simple representation of these processes that involves three free parameters. A reasonable value can be chosen for one of these, and the other two can be optimized to yield a good fit to the proton conductance data of Eisenman et al. (1980, Ann. N.Y. Acad. Sci. 339:8-20) for pH greater than or equal to 1.7. A sensitivity analysis shows the significance of this fit. C1 Washington State Univ, Dept Pure & Appl Math, Pullman, WA 99164 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM 87545 USA. Washington State Univ, Dept Pure & Appl Math, Pullman, WA 99164 USA. RP Schumaker, MF (reprint author), Washington State Univ, Dept Pure & Appl Math, Pullman, WA 99164 USA. NR 46 TC 55 Z9 55 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD DEC PY 2000 VL 79 IS 6 BP 2840 EP 2857 PG 18 WC Biophysics SC Biophysics GA 381EH UT WOS:000165749000006 PM 11106593 ER PT J AU Fox, SL Bala, GA AF Fox, SL Bala, GA TI Production of surfactant from Bacillus subtilis ATCC 21332 using potato substrates SO BIORESOURCE TECHNOLOGY LA English DT Article DE biosurfactant; B. subtilis; potato substrates AB Surfactin, a lipopeptide biosurfactant, produced by Bacillus subtilis is known to reduce the surface tension of water from 72 to 27 mN/m. Potato substrates were evaluated as a carbon source for surfactant production by B. subtilis ATCC 21332. An established potato medium, simulated liquid and solid potato waste media, and a commercially prepared potato starch in a mineral salts medium were evaluated in shake flask experiments to verify growth, surface tension reduction, and carbohydrate reduction capabilities. Total carbohydrate assays and glucose monitoring indicated that B. subtilis was able to degrade potato substrates to produce surfactant. Surface tensions dropped from 71.3 +/- 0.1 to 28.3 +/- 0.3 mN/m (simulated solid potato medium) and to 27.5 +/- 0.3 mN/m (mineral salts medium). A critical micelle concentration (CMC) of 0.10 g/l was obtained from a methylene chloride extract of the simulated solid potato medium. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Bechtel BWXT Idaho, LLC, Idaho Natl Engn & Environm Lab, Dept Biotechnol, Idaho Falls, ID 83415 USA. RP Fox, SL (reprint author), Bechtel BWXT Idaho, LLC, Idaho Natl Engn & Environm Lab, Dept Biotechnol, POB 1625,MS 2203, Idaho Falls, ID 83415 USA. NR 16 TC 89 Z9 95 U1 4 U2 20 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0960-8524 J9 BIORESOURCE TECHNOL JI Bioresour. Technol. PD DEC PY 2000 VL 75 IS 3 BP 235 EP 240 DI 10.1016/S0960-8524(00)00059-6 PG 6 WC Agricultural Engineering; Biotechnology & Applied Microbiology; Energy & Fuels SC Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels GA 341ZK UT WOS:000088620700011 ER PT J AU Montenegro, FC Lima, KA Torikachvili, MS Lacerda, AH AF Montenegro, FC Lima, KA Torikachvili, MS Lacerda, AH TI Instability of long-range order in a d=3 random-field Ising model system: FexZn1-xF2 SO BRAZILIAN JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT Ising Centennial Colloquium CY AUG 01-04, 2000 CL UNIV FED MINAS GERAIS, BELO HORIZONT, BRAZIL HO UNIV FED MINAS GERAIS ID BEHAVIOR AB Instabilities of long-range order are observed in samples of the d = 3 dilute uniaxial antiferromagnet FexZn1-xF2 with x = 0.56 and 0.41, under strong random fields. The onset of instability, mapped in the (H, T) phase diagrams of the samples, reveals that the H, T and x dependence of the effective random field is in qualitative agreement with a mean-field expression predicted in the weak-field limit for site diluted antiferromagnets. C1 UFPE, Dept Fis, BR-50670901 Recife, PE, Brazil. San Diego State Univ, Dept Phys, San Diego, CA 92182 USA. Univ Calif Los Alamos Natl Lab, Natl High Magnet Field Lab, Pulse Facil, Los Alamos, NM 87545 USA. RP Montenegro, FC (reprint author), UFPE, Dept Fis, BR-50670901 Recife, PE, Brazil. NR 11 TC 1 Z9 1 U1 0 U2 0 PU SOCIEDADE BRASILEIRA FISICA PI SAO PAULO PA CAIXA POSTAL 66328, 05315-970 SAO PAULO, BRAZIL SN 0103-9733 J9 BRAZ J PHYS JI Braz. J. Phys. PD DEC PY 2000 VL 30 IS 4 BP 758 EP 761 DI 10.1590/S0103-97332000000400023 PG 4 WC Physics, Multidisciplinary SC Physics GA 397XA UT WOS:000166722300023 ER PT J AU Stephens, GL Ellingson, RG Vitko, J Bolton, W Tooman, TP Valero, FPJ Minnis, P Pilewskie, P Phipps, GS Sekelsky, S Carswell, JR Miller, SD Benedetti, A McCoy, RB McCoy, RF Lederbuhr, A Bambha, R AF Stephens, GL Ellingson, RG Vitko, J Bolton, W Tooman, TP Valero, FPJ Minnis, P Pilewskie, P Phipps, GS Sekelsky, S Carswell, JR Miller, SD Benedetti, A McCoy, RB McCoy, RF Lederbuhr, A Bambha, R TI The Department of Energy's Atmospheric Radiation Measurement (ARM) Unmanned Aerospace Vehicle (UAV) program SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SHORTWAVE EXPERIMENT ARESE; CLOUD; PARAMETERIZATION; ABSORPTION; RETRIEVAL; AIRCRAFT; SUCCESS AB The U.S. Department of Energy has established an unmanned aerospace vehicle (UAV) measurement program. The purpose of this paper is to describe the evolution of the program since its inception, review the progress of the program, summarize the measurement capabilities developed under the program, illustrate key results from the various UAV campaigns carried out to date, and provide a sense of the future direction of the program. The Atmospheric Radiation Measurement (ARM)-UAV program has demonstrated how measurements from unmanned aircraft platforms operating under the various constraints imposed by different science experiments can contribute to our understanding of cloud and radiative processes. The program was first introduced in 1991 and has evolved in the form of four phases of activity each culminating in one or more flight campaigns. A total of 8 flight campaigns produced over 140 h of science flights using three different UAV platforms. The UAV platforms and their capabilities are described as are the various phases of the program development. Examples of data collected from various campaigns highlight the powerful nature of the observing system developed under the auspices of the ARM-UAV program and confirm the viability of the UAV platform for the kinds of research of interest to ARM and the clouds and radiation community as a whole. The specific examples include applications of the data in the study of radiative transfer through clouds, the evaluation of cloud parameterizations, and the development and evaluation of cloud remote sensing methods. A number of notable and novel achievements of the program are also highlighted. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Sandia Natl Labs, Livermore, CA USA. Scripps Inst Oceanog, San Diego, CA USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. NASA, Ames Res Ctr, Sunnyvale, CA USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. Univ Calif Davis, Crocker Nucl Lab, Davis, CA 95616 USA. RP Stephens, GL (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 27 TC 21 Z9 21 U1 2 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD DEC PY 2000 VL 81 IS 12 BP 2915 EP 2937 DI 10.1175/1520-0477(2000)081<2915:TDOESA>2.3.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 379ZG UT WOS:000165672600001 ER PT J AU Begnaud, ML McNally, KC Stakes, DS Gallardo, VA AF Begnaud, ML McNally, KC Stakes, DS Gallardo, VA TI A crustal velocity model for locating earthquakes in Monterey Bay, California SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID CONTINENTAL-MARGIN; LOMA-PRIETA; SAN-ANDREAS; TRANSFORM; TOMOGRAPHY; BENEATH; PLATE; EDGE AB The seismicity of the Monterey Bay displays a sparse distribution of events with a majority in northern Monterey Bay, on the San Gregorio fault. The paucity of near-shore and offshore seismic recording instruments and the use of velocity models from inland regions for earthquake hypocentral locations and focal mechanisms have led to uncertainties and inaccuracies for seismic events on major faults that crosscut the Bay. New three-component seismic data were acquired during 1997-1999 by the Monterey Bay Aquarium Research Institute (MBARI) Margin Seismology project using ocean-bottom digital corehole and standard seismometers, and coastal digital RefTek instruments obtained from IRIS-PASSCAL by the University of California, Santa Cruz, We have analyzed phases from earthquakes in the Monterey Bay vicinity located by these instruments and used them to supplement the adjacent coastal stations of the permanent Northern California Seismic Network. A new one-dimensional velocity model for the region requires slow velocities from 2 to 6 km that we attribute to sheared granites observed in the Salinian Block in the center of Monterey Bay. Velocities in the 10-16 km layer are consistent with continental crustal velocities. A sharp increase in velocity at similar to 16 km suggests a boundary that results from underplating of oceanic crust. This underplated zone appears to extend to a depth of similar to 27-30 km where we observe normal upper mantle velocities near 8.0 km/sec. New details from the ocean-bottom corehole and coastal RefTek instruments for events along the SGF and Monterey Bay fault zones hint at local fine-scale structures and have implications for tectonic history and plate reconstruction interpretation. C1 Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Inst Tecton, Santa Cruz, CA 95064 USA. Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. RP Begnaud, ML (reprint author), Univ Calif Los Alamos Natl Lab, EES-3,MS D408, Los Alamos, NM 87545 USA. NR 34 TC 8 Z9 8 U1 0 U2 1 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD DEC PY 2000 VL 90 IS 6 BP 1391 EP 1408 DI 10.1785/0120000016 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 398PK UT WOS:000166764700004 ER PT J AU Kozeschnik, E Vitek, JM AF Kozeschnik, E Vitek, JM TI Ortho-equilibrium and para-equilibrium phase diagrams for interstitial/substitutional iron alloys SO CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY LA English DT Article ID STEELS; MARTENSITE AB A mathematical model for the evaluation of compositionally constrained thermodynamic equilibrium has recently been implemented into the computer program MatCalc. This model is applied to the calculation of para-equilibrium phase diagrams for some ternary model iron alloy systems Fe-X-C, with X = Mn, Ni, Cr and Mo. The results are compared to the corresponding full equilibrium (ortho-equilibrium) phase diagrams and the impact of each element on the austenite / ferrite / carbide transformation in steels is analyzed. The pars-equilibrium phase diagrams are considerably more simple than the potentially complex ortho-equilibrium phase diagrams, showing cementite formation as the only stable carbide under para-equilibrium conditions. The driving forces for precipitation of cementite and the complex chromium carbides in the Fe-Cr-C system are evaluated as a function of the predicts composition. The evaluation of the driving forces under para-equilibrium conditions predicts carbide precipitation behavior that agrees with experimental findings. C1 Mat Ctr, Leoben, Austria. Graz Univ Technol, Inst Mat Sci Welding & Forming, A-8010 Graz, Austria. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Kozeschnik, E (reprint author), Mat Ctr, Leoben, Austria. NR 10 TC 10 Z9 10 U1 2 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0364-5916 J9 CALPHAD JI Calphad-Comput. Coupling Ph. Diagrams Thermochem. PD DEC PY 2000 VL 24 IS 4 BP 495 EP 502 DI 10.1016/S0364-5916(01)00020-7 PG 8 WC Thermodynamics; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Thermodynamics; Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 445WY UT WOS:000169482600007 ER PT J AU Anders, M Hansen, RK McCormick, F Bissell, MJ Korn, WM AF Anders, M Hansen, RK McCormick, F Bissell, MJ Korn, WM TI The expression of the human Coxsackie and Adenovirus receptor (CAR) depends on the three-dimensional organization of epithelial cells SO CANCER GENE THERAPY LA English DT Meeting Abstract C1 Univ Calif San Francisco, Ctr Comprehens Canc, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Med, Div Gastroenterol, San Francisco, CA 94143 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0929-1903 J9 CANCER GENE THER JI Cancer Gene Ther. PD DEC PY 2000 VL 7 IS 12 SU S MA PD41 BP S12 EP S12 PG 1 WC Biotechnology & Applied Microbiology; Oncology; Genetics & Heredity; Medicine, Research & Experimental SC Biotechnology & Applied Microbiology; Oncology; Genetics & Heredity; Research & Experimental Medicine GA 379LK UT WOS:000165643400041 ER PT J AU Srivastava, SC Meinken, GE Freimuth, P AF Srivastava, SC Meinken, GE Freimuth, P TI In vivo binding to CAR of In-111 and I-131 labeled adenoviral vectors of varying molecular size SO CANCER GENE THERAPY LA English DT Meeting Abstract C1 Brookhaven Natl Lab, Upton, NY 11973 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI BASINGSTOKE PA HOUNDMILLS, BASINGSTOKE RG21 6XS, HAMPSHIRE, ENGLAND SN 0929-1903 J9 CANCER GENE THER JI Cancer Gene Ther. PD DEC PY 2000 VL 7 IS 12 SU S MA PD43 BP S13 EP S13 PG 1 WC Biotechnology & Applied Microbiology; Oncology; Genetics & Heredity; Medicine, Research & Experimental SC Biotechnology & Applied Microbiology; Oncology; Genetics & Heredity; Research & Experimental Medicine GA 379LK UT WOS:000165643400043 ER PT J AU Hively, LM Protopopescu, VA Gailey, PC AF Hively, LM Protopopescu, VA Gailey, PC TI Timely detection of dynamical change in scalp EEG signals SO CHAOS LA English DT Article ID OBSERVED CHAOTIC DATA; EPILEPTIC SEIZURES; CORRELATION INTEGRALS; STRANGE ATTRACTORS; NONLINEAR-ANALYSIS; SERIES ANALYSIS; REAL-TIME; NONSTATIONARITY; DIMENSIONS; SYSTEMS AB We present a robust, model-independent technique for quantifying changes in the dynamics underlying nonlinear time-serial data. After constructing discrete density distributions of phase-space points on the attractor for time-windowed data sets, we measure the dissimilarity between density distributions via L-1-distance and chi (2) statistics. The discriminating power of the new measures is first tested on data generated by the Bondarenko "synthetic brain" model. We also compare traditional nonlinear measures and the new dissimilarity measures to detect dynamical change in scalp EEG data. The results demonstrate a clear superiority of the new measures in comparison to traditional nonlinear measures as robust and timely discriminators of changing dynamics. (C) 2000 American Institute of Physics. [S1054-1500(00)00504-8]. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Ohio Univ, Dept Phys & Astron, Athens, OH 45701 USA. RP Hively, LM (reprint author), Oak Ridge Natl Lab, POB 2009, Oak Ridge, TN 37831 USA. NR 44 TC 31 Z9 31 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1054-1500 J9 CHAOS JI Chaos PD DEC PY 2000 VL 10 IS 4 BP 864 EP 875 AR PII [S1054-1500(00)00504-8] DI 10.1063/1.1312369 PG 12 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 378LA UT WOS:000165584800012 ER PT J AU Mann, NR Todd, TA AF Mann, NR Todd, TA TI Crossflow filtration testing of INEEL radioactive and non-radioactive waste slurries SO CHEMICAL ENGINEERING JOURNAL LA English DT Article; Proceedings Paper CT International Conference on Solid-Liquid Separation Systems CY APR, 1999 CL OAHU, HAWAII SP United Engn Fdn, Natl Sci Fdn, Amer Inst Chem Engineers, Amer Filrat & Separat Soc, British Filrat Soc DE solid-liquid separation; filtration; crossflow; radioactive waste slurries; Idaho National Engineering and Environmental Laboratory AB Development of waste treatment processes for the remediation of radioactive wastes is currently under way at the Idaho Nuclear Technology and Engineering Center (INTEC), located at the Idaho National Engineering and Environmental Laboratory (INEEL). INTEC, formerly known as the Idaho Chemical Processing Plant, previously reprocessed nuclear fuel to retrieve fissionable uranium. Liquid waste raffinates resulting from reprocessing were solidified into a calcine material. Waste treatment processes currently being considered include the dissolution of the solidified calcine material and separation of residual undissolved solids (UDS). UDS in solution must be removed prior to downstream processes such as solvent extraction and ion exchange. Filtration experiments were conducted at the INEEL using a crossflow filter apparatus on radioactive and non-radioactive waste slurries [N.R. Mann, T.A. Todd, Evaluation and Testing of the Cells Units Crossflow Filter on INEEL Dissolved Calcine Slurries, INEEL/EXT-98-00749, Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID, 1998]. The purpose of this testing was to evaluate the removal and operational efficiency of crossflow filtration on slurries of various solids loadings. The solids loadings tested were 0.19, 2.44 and 7.94 wt.%, respectively. A matrix of test patterns was used to determine the effects of transmembrane pressure and axial velocity on filtrate flux. Filtrate flux rates for each solids loading displayed a high dependence on transmembrane pressure, indicating that pressure filtration resistance limits filtrate flux. Filtrate flux rates for all solids loading displayed a negative dependency on axial velocity. This would suggest axial velocities tested were efficient at removing filter cake. Prior to testing of actual waste slurries, baseline water runs were performed, Filtrate flowrates observed during baseline water runs exhibited substantial decreases despite numerous backpulses and rinses, suggesting particles that were deeply embedded within the filter membrane as the result of shear-induced deagglomeration (C) 2000 Elsevier Science B.V. All rights reserved. C1 Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Mann, NR (reprint author), Lockheed Martin Idaho Technol Co, Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. RI Todd, Terry /O-4930-2016 OI Todd, Terry /0000-0003-1324-6950 NR 6 TC 9 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1385-8947 J9 CHEM ENG J JI Chem. Eng. J. PD DEC 1 PY 2000 VL 80 IS 1-3 SI SI BP 237 EP 244 DI 10.1016/S1383-5866(00)00096-4 PG 8 WC Engineering, Environmental; Engineering, Chemical SC Engineering GA 381CC UT WOS:000165743900027 ER PT J AU Jackson, KA Knickelbein, M Koretsky, G Srinivas, S AF Jackson, KA Knickelbein, M Koretsky, G Srinivas, S TI The interaction of ammonia with small iron clusters: infrared spectra and density functional calculations of Fe-n(NH3)(m) and Fe-n(ND3)(m) complexes SO CHEMICAL PHYSICS LA English DT Article ID TRANSITION-METAL CLUSTERS; GENERALIZED GRADIENT APPROXIMATION; IONIZATION-POTENTIALS; NICKEL CLUSTERS; ELECTRONIC-STRUCTURE; VIBRATIONAL-SPECTRA; NIOBIUM CLUSTERS; CHEMICAL PROBES; BINDING-ENERGY; FE-N AB Bare iron clusters react in the gas phase with ammonia to form Fe-n(NH3)(m) complexes. In the present study, the iron cluster-ammonia interaction within Fe-n(NH3)(m) and Fe-n(ND3)(m) complexes (n = 7-16) are investigated by molecular beam infrared depletion spectroscopy and density functional theory (DFT) calculations. Experimentally, we observe an absorption band within Fe-n(ND3)(m) complexes in the 880-890 cm(-1) range, which is attributed to the v(2) inversion mode of ND3. DFT calculations performed for Fe-n(NH3)(m) and Fe-n(ND3)(m) model complexes (n = 1, 4, 7, and 13) predict that three of the four vibrational fundamentals of ammonia are only slightly shifted from their gas phase values, but that the symmetric v(2) fundamental shifts substantially upward in the complex. For ND3, v(2) is predicted to shift from 748 cm(-1) to the 850-900 cm(-1) range when adsorbed to Fe-n, as is observed experimentally in both the present cluster study and in iron single-crystal surface studies. DFT calculations of vertical ionization potentials of Fe-n/Fe-n(NH3)(m) species and of Fe-n-NH3 binding energies are found to be in near-quantitative agreement with previously measured values. Published by Elsevier Science B.V. C1 Cent Michigan Univ, Dept Phys, Mt Pleasant, MI 48859 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Knickelbein, M (reprint author), Cent Michigan Univ, Dept Phys, Mt Pleasant, MI 48859 USA. OI Jackson, Koblar/0000-0002-5342-7978 NR 51 TC 15 Z9 15 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD DEC 1 PY 2000 VL 262 IS 1 SI SI BP 41 EP 51 DI 10.1016/S0301-0104(00)00266-4 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382JG UT WOS:000165818700007 ER PT J AU Wang, LS Li, X Zhang, HF AF Wang, LS Li, X Zhang, HF TI Probing the electronic structure of iron clusters using photoelectron spectroscopy SO CHEMICAL PHYSICS LA English DT Article ID TRANSITION-METAL CLUSTERS; SMALL CHROMIUM CLUSTERS; GUIDED ION-BEAM; OXIDE CLUSTERS; MAGNETIC-PROPERTIES; BOND-ENERGIES; IONIZATION-POTENTIALS; BINDING-ENERGIES; NICKEL CLUSTERS; SIZE DEPENDENCE AB The electronic structure of small iron clusters, Fe(n)(-) (n = 3-34), was investigated using size-selected anion photoelectron spectroscopy at three photon energies: 355, 266, and 193 nm. Temperature-dependent studies were performed for selected clusters at 355 nm. The spectra of cold clusters at 355 nm revealed well-resolved electronic transitions. An unusually sharp threshold peak was observed for a number of clusters, particularly for n = 12-15, The electronic structure variations as a function of size were found to correlate well with changes in the cluster chemical reactivity in the same size ranges. The 193-nm photoelectron spectra, which provided a broader range of valence band electronic structures for the clusters, were compared to bulk photoemission spectra. The electronic structure revealed at 193 nm was found to exhibit bulk-like behavior starting at Fe(25). This observation was also consistent with the size dependence of the cluster electron affinities, ionization potentials, and chemical reactivity, which all showed more smooth size variations above Fe(25). It was also shown that the obtained electronic structure information from the well-resolved photoelectron spectra will be valuable to compare with and verify ab initio calculations in order to completely understand the chemical, structural, and magnetic properties of the iron clusters. (C) 2000 Published by Elsevier Science B.V. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. EM ls.wang@pnl.gov NR 87 TC 67 Z9 70 U1 0 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD DEC 1 PY 2000 VL 262 IS 1 SI SI BP 53 EP 63 DI 10.1016/S0301-0104(00)00351-7 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382JG UT WOS:000165818700008 ER PT J AU Parks, EK Kerns, MP Riley, SJ AF Parks, EK Kerns, MP Riley, SJ TI The structure of nickel-iron clusters probed by adsorption of molecular nitrogen SO CHEMICAL PHYSICS LA English DT Article ID COBALT CLUSTERS; SHELL STRUCTURE; METAL-CLUSTERS; BIMETALLIC CLUSTERS; PHOTODISSOCIATION; PHOTOIONIZATION; REACTIVITY; BINDING; ALLOY AB The isomeric structures of small nickel-rich nickel-iron alloy clusters are probed via the adsorption of molecular nitrogen on their surfaces. A determination of nitrogen saturation levels allows the location of the iron atoms to be established. Experiments on pure iron clusters demonstrate very little adsorption of molecular nitrogen under conditions where pure nickel clusters show saturated coverages. This low adsorption on iron appears to carry over to the alloy clusters. If the iron atoms are on the surface of a cluster, nitrogen saturation levels are lower than for pure nickel clusters, while if they are inside, coverage levels are the same. Results are presented for clusters containing 13, 19, 20, 23, 26, and 48-53 atoms. They show that alloy clusters in the size ranges where nickel clusters tend to have icosahedral or polyicosahedral packing are most stable with the iron atoms located inside. Unlike other clusters, Ni(26) shows a clear change in geometrical structure when a single nickel atom is replaced by an iron atom. Evidence is also presented for the formation of metastable isomeric configurations in which iron atoms are located outside. These isomers convert to the more stable ones in the experimental time scale of a few ms. The effect of the nitrogen overlayer on the conversion process is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Riley, SJ (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM sjriley@anl.gov NR 33 TC 39 Z9 39 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-0104 J9 CHEM PHYS JI Chem. Phys. PD DEC 1 PY 2000 VL 262 IS 1 SI SI BP 151 EP 167 DI 10.1016/S0301-0104(00)00141-5 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 382JG UT WOS:000165818700016 ER PT J AU Manaa, MR AF Manaa, MR TI Toward new energy-rich molecular systems: from N-10 to N-60 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID TETRAHEDRAL N-4; NITROGEN; DISSOCIATION; C60; PRESSURES; PENTALENE; ISOMERS; CUBANE; MBAR; N8 AB The electronic structure calculations locate the local minima for bicyclic N-10 and the fullerene analog N-60, both as high-energy density species. The bridging N-N bond in N-10 is quite remarkably strong (DeltaE [N-10 --> 2N(5)] = 93 kcal/ mol), yet flexible to allow a facile rotation of one ring with respect to the other. This property could permit Nio to serve as a building block for specific clustering into the nitrogen buckminsterfullerene structure. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Energet Mat Ctr, Livermore, CA 94551 USA. RP Manaa, MR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Energet Mat Ctr, L-282,POB 808, Livermore, CA 94551 USA. NR 32 TC 54 Z9 59 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 1 PY 2000 VL 331 IS 2-4 BP 262 EP 268 DI 10.1016/S0009-2614(00)01164-7 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 380UG UT WOS:000165721400023 ER PT J AU Manas, ES Chen, LX AF Manas, ES Chen, LX TI Electronic interactions in metal complexed photoconducting polymers: a ZINDO study SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PI-CONJUGATED OLIGOMERS; TRANSFER EXCITED-STATES; INTERMEDIATE NEGLECT; CHELATING LIGAND; PHOTOPHYSICS; SPECTRA; CHROMOPHORES AB Semi-empirical (INDO/s) calculations have been conducted on molecular fragments with zero to three phenylenevinylene (PV) units attached to 4 and 4' positions of a 2,2'-bipyridine (bpy) group, with and without chelated metal ions, mimicking metal-free and metal-chelated photoconducting polymers 1 and 2 [Chen et al., J. Phys. Chem. B 104 (2000) 1950]. The calculations suggest that: (1) a global lowering of the molecular orbital energy levels due to metal-chelation is responsible for the observed red-shift in the lowest energy transitions; and (2) metal chelation attenuates pi -electron delocalization. The relevance of these effects to photoluminescence of metal-chelated polymers is also discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Penn, Sch Med, Dept Biochem & Biophys, Philadelphia, PA 19104 USA. RP Chen, LX (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 33 TC 15 Z9 15 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD DEC 1 PY 2000 VL 331 IS 2-4 BP 299 EP 307 DI 10.1016/S0009-2614(00)01190-8 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 380UG UT WOS:000165721400028 ER PT J AU Schneider, JJ Czap, N Hagen, J Engstler, J Ensling, J Gutlich, P Reinoehl, U Bertagnolli, H Luis, F de Jongh, LJ Wark, M Grubert, G Hornyak, GL Zanoni, R AF Schneider, JJ Czap, N Hagen, J Engstler, J Ensling, J Gutlich, P Reinoehl, U Bertagnolli, H Luis, F de Jongh, LJ Wark, M Grubert, G Hornyak, GL Zanoni, R TI Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: Formation, physical properties, and chemical reactivity SO CHEMISTRY-A EUROPEAN JOURNAL LA English DT Review DE aluminum; iron; nanostructures; oxides; titanium ID ATOM DISPERSED CATALYSTS; RAY PHOTOELECTRON-SPECTROSCOPY; POLARIZABLE WATER MODEL; ULTRAFINE CARBON TUBES; MAGNETIC-PROPERTIES; ADSORPTION-ISOTHERMS; TIO2 PARTICLES; ELECTRONIC-STRUCTURE; MOSSBAUER SPECTRUM; CRYSTAL-STRUCTURE AB Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mossbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mossbauer spectra on temperature and particle size is explained by the influence of superparamagnetic relaxation effects. The coexistence of a paramagnetic doublet and a magnetically split component in the spectra is further explained by a distribution in particle size. From Mossbauer parameters the oxide phase can be identified as low-crystallinity ferrihydrite oxide. In agreement with quantum size effects observed in UV-visible studies, TEM measurements determine the size of the particles in the range 5-8 nm. The particles are mainly arranged alongside the pore walls of the alumina template. TiO(2) nanoparticles are formed by depositing 2 in mesoporous alumina template. This produces metallic Ti, which is subsequently oxidized to TiO(2) (anatase) within the alumina pores. UV-visible studies show a strong quantum confinement effect for these particles. From UV-visible investigations the particle size is determined to be around 2nm. XPS analysis of the iron- and titania- embedded nanoparticles reveal the presence of Fe(2)O(3) and TiO(2) according to experimental binding energies and the experimental line shapes. Ti(4+) and Fe(3+) are the only oxidation states of the particles which can be determined by this technique. Hydrogen reduction of the iron/iron-oxide nanoparticles at 500 degreesC under flowing H(2)/N(2) produces a catalyst, which is active towards formation of carbon nanotubes by a CVD process. Depending on the reaction conditions, the formation of smaller carbon nanotubes inside the interior of larger carbon nanotubes within the alumina pores can be achieved. This behavior can be understood by means of selectively turning on and off the iron catalyst by adjusting the flow rate of the gaseous carbon precursor in the CVD process. C1 Univ Essen Gesamthsch, Inst Anorgan Chem, D-45117 Essen, Germany. Johannes Gutenberg Univ Mainz, Inst Anorgan & Analyt Chem, D-55099 Mainz, Germany. Univ Stuttgart, Inst Phys Chem, D-70569 Stuttgart, Germany. Leiden Univ, Kamerlingh Onnes Lab, NL-2300 RA Leiden, Netherlands. Univ Bremen, Inst Angew & Phys Chem, D-28359 Bremen, Germany. Natl Renewable Energy Lab, Golden, CO 80401 USA. Univ Roma La Sapienza, Dipartimento Chim, I-00185 Rome, Italy. RP Schneider, JJ (reprint author), Graz Univ, Inst Chem, Schubertstr 1, A-8010 Graz, Austria. EM joerg.schneider@kfunigraz.ac.at RI LUIS, Fernando/E-9108-2011; Schneider, Jorg /C-6308-2013; Zanoni, Robertino/A-1742-2008 OI LUIS, Fernando/0000-0001-6284-0521; Schneider, Jorg /0000-0002-8153-9491; Zanoni, Robertino/0000-0003-2419-309X NR 155 TC 29 Z9 30 U1 9 U2 48 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0947-6539 J9 CHEM-EUR J JI Chem.-Eur. J. PD DEC 1 PY 2000 VL 6 IS 23 BP 4305 EP 4321 DI 10.1002/1521-3765(20001201)6:23<4305::AID-CHEM4305>3.0.CO;2-N PG 17 WC Chemistry, Multidisciplinary SC Chemistry GA 381NF UT WOS:000165768700007 PM 11140960 ER PT J AU Loy, DA Baugher, BM Baugher, CR Schneider, DA Rahimian, K AF Loy, DA Baugher, BM Baugher, CR Schneider, DA Rahimian, K TI Substituent effects on the sol-gel chemistry of organotrialkoxysilanes SO CHEMISTRY OF MATERIALS LA English DT Article ID HYDROLYSIS AB Silsesquioxanes are a family of siloxane network polymers that have become important as vehicles for introducing organic functionalities into sol-gel materials. However, there has not been a systematic study of the capacity of organotrialkoxysilanes to form gels through the sol-gel process. In this study, we examined the sol-gel chemistry of:organotrialkoxysilanes (RSi(OR ')(3)) with different organic groups (R = H, Me, Et, Pr, i-Pr, n-Bu, i-Bu, t-Bu, hexyl, octyl, decyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, vinyl, phenyl, benzyl, phenethyl, chloromethyl, chloromethylphenyl, and tridecafluoro-1,1,2,2-tetrahydrooctyl) with methoxide or ethoxide substituents on silicon, at varying monomer concentrations, and under acidic, neutral, and basic conditions. Gels were obtained from the sol-gel polymerization of the monomers with R '= Me and R = H, Me, vinyl, chloromethyl, chloromethylphenyl, hexadecyl, and octadecyl and R ' = Et and R = H, Me, Et, chloromethyl, vinyl, dodecyl, hexadeeyl, and octadecyl. Formation of gels, even with these monomers, was often circumvented by phase separation phenomena, giving rise to crystalline oligomers, resinous materials, and precipitates. Gels obtained from these polymerizations were processed as xerogels and characterized by solid-state,NMR, microscopy, and nitrogen sorption porosimetry. C1 Sandia Natl Labs, Catalysis & Chem Technol Dept, Albuquerque, NM 87185 USA. RP Loy, DA (reprint author), Sandia Natl Labs, Catalysis & Chem Technol Dept, POB 5800, Albuquerque, NM 87185 USA. RI Loy, Douglas/D-4847-2009 OI Loy, Douglas/0000-0001-7635-9958 NR 18 TC 197 Z9 204 U1 6 U2 47 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD DEC PY 2000 VL 12 IS 12 BP 3624 EP 3632 DI 10.1021/cm000451i PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 386QT UT WOS:000166073600017 ER PT J AU Clark, T Ruiz, JD Fan, HY Brinker, CJ Swanson, BI Parikh, AN AF Clark, T Ruiz, JD Fan, HY Brinker, CJ Swanson, BI Parikh, AN TI A new application of UV-ozone treatment in the preparation of substrate-supported, mesoporous thin films SO CHEMISTRY OF MATERIALS LA English DT Article ID SILICA FILMS AB A nominally room temperature photochemical method, simply employing ultraviolet light(187-254 nm) generated ozone environment, is shown to provide an efficient alternative for the removal of surfactant templates for a routine production of mesoporous silica thin films at low temperatures. The treatment concomitantly strengthens the silicate phase by fostering the condensation of unreacted silanols leading to mesoporous thin films with well-defined mesoscopic morphologies. The surfactant/silicate thin film mesophases were prepared onto a polycrystalline Au surface by dip-coating or spin-casting methods using sub-critical micelle concentration (cmc) nonionic ethylene oxide surfactant in an oligomeric silica sol mixture. The structures and compositions of the thin film mesophases before and after exposure to UV/ozone were determined using a combination of reflection-absorption Fourier transform infrared spectroscopy, transmission electron microscopy, and thin film X-ray diffraction measurements. The pore characteristics of the UV/ozone-treated films were determined using nitrogen adsorption/desporption isotherm measurements. Results presented here clearly establish that the UV/ozone processing leads to complete removal of the surfactant template; strengthens the inorganic skeleton by fostering silica condensation; and renders the mesophase thin film surfaces highly hydrophilic. Two of the most attractive features of the method developed here, namely its usefulness in applications for temperature intolerant substrates (e.g., thin metal films) and in spatially selective removal of the surfactant templates to create patterns of mesoporous thin films, are also illustrated. Finally, the mechanistic implications of these observations are also discussed. C1 Univ New Mexico, NSF Ctr Microengn Mat, Adv Mat Lab, Albuquerque, NM 87106 USA. Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Sandia Natl Labs, Dept 1831, Albuquerque, NM 87131 USA. RP Brinker, CJ (reprint author), Univ New Mexico, NSF Ctr Microengn Mat, Adv Mat Lab, 1001 Univ Blvd SE, Albuquerque, NM 87106 USA. RI PARIKH, ATUL/D-2243-2014 OI PARIKH, ATUL/0000-0002-5927-4968 NR 30 TC 94 Z9 95 U1 1 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD DEC PY 2000 VL 12 IS 12 BP 3879 EP 3884 DI 10.1021/cm000456f PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 386QT UT WOS:000166073600052 ER PT J AU Day, MS Bell, JB AF Day, MS Bell, JB TI Numerical simulation of laminar reacting flows with complex chemistry SO COMBUSTION THEORY AND MODELLING LA English DT Article ID ADAPTIVE PROJECTION METHOD; NAVIER-STOKES EQUATIONS; LOW-MACH NUMBER; FLAMES; SCHEME; STIFF; SLIT AB We present an adaptive algorithm for low Mach number reacting flows with complex chemistry. Our approach uses a form of the low Mach number equations that discretely conserves both mass and energy. The discretization methodology is based on a robust projection formulation that accommodates large density contrasts. The algorithm uses an operator-split treatment of stiff reaction terms and includes effects of differential diffusion. The basic computational approach is embedded in an adaptive projection framework that uses structured hierarchical grids with subcycling in time that preserves the discrete conservation properties of the underlying single-grid algorithm. We present numerical examples illustrating the performance of the method on both premixed and non-premixed dames. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Day, MS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 39 TC 144 Z9 146 U1 0 U2 20 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 1364-7830 J9 COMBUST THEOR MODEL JI Combust. Theory Model. PD DEC PY 2000 VL 4 IS 4 BP 535 EP 556 DI 10.1088/1364-7830/4/4/309 PG 22 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Mathematics, Interdisciplinary Applications SC Thermodynamics; Energy & Fuels; Engineering; Mathematics GA 385QR UT WOS:000166015600009 ER PT J AU Butler, R Welch, V Engert, D Foster, I Tuecke, S Volmer, J Kesselman, C AF Butler, R Welch, V Engert, D Foster, I Tuecke, S Volmer, J Kesselman, C TI A national-scale authentication infrastructure SO COMPUTER LA English DT Article AB The authors' Grid Security infrastructure lets users access resources at any participating site without repeated authentication, while preserving a site's ability to use site- specific security mechanisms and enforce local access control. C1 Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ So Calif, Inst Sci Informat, Los Angeles, CA 90089 USA. RP Butler, R (reprint author), Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. OI Tuecke, Steven/0000-0003-2038-2512 NR 8 TC 70 Z9 70 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0018-9162 J9 COMPUTER JI Computer PD DEC PY 2000 VL 33 IS 12 BP 60 EP + PG 8 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering SC Computer Science GA 377LT UT WOS:000165515600017 ER PT J AU Sander V Foster I Roy, A Winkler, L AF Sander, V Foster, I Roy, A Winkler, L TI A differentiated services implementation for high-performance TCP flows SO COMPUTER NETWORKS LA English DT Article; Proceedings Paper CT TEREBA Networking Conference 2000 on Pioneering Tomorrows Internet CY MAY 22-25, 2000 CL LISBON, PORTUGAL DE bandwidth broker; differentiated services; quality of service; transmission control protocol AB The IETF's recent differentiated services (DS) architecture, which specifies a scalable mechanism for treating packets differently, offers new opportunities for building end-to-end quality of service (QoS) systems. However, it also introduces new challenges. In particular, it is not clear whether TCP's how and congestion control mechanisms work well with the mechanisms used for end-to-end QoS. For that reason it is essential to analyze whether the existing DS mechanisms can be used with standard TCP implementations or whether it is necessary to wait for upcoming features introduced in future modified versions of TCP. The general-purpose architecture for reservation and allocation (GARA) supports flow-specific QoS specification, immediate and advance reservation, and online monitoring and control of both individual resources and heterogeneous resource ensembles. Using GARA, we evaluated actual DS mechanisms provided by Cisco routers. We present the results of this evaluation and discuss their impact on the performance of popular TCP implementations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Forschungszentrum Julich, Cent Inst Appl Math, D-52425 Julich, Germany. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Univ Chicago, Dept Comp Sci, Chicago, IL 60637 USA. RP Sander V (reprint author), Forschungszentrum Julich, Cent Inst Appl Math, Postfach 1913, D-52425 Julich, Germany. EM v.sander@fz-juelich.de RI Foster, Ian/A-1357-2007 OI Foster, Ian/0000-0003-2129-5269 NR 23 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD DEC PY 2000 VL 34 IS 6 BP 915 EP 929 DI 10.1016/S1389-1286(00)00162-6 PG 15 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 372TV UT WOS:000165250900011 ER PT J AU Qiang, J Ryne, RD Habib, S AF Qiang, J Ryne, RD Habib, S TI Fortran implementation of object-oriented design in parallel beam dynamics simulations SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE object-oriented; F90/MPI; HPF; beam dynamics; particle-in-cell ID PLASMA AB In this paper, an object-oriented design for parallel beam transport simulations in accelerators is implemented using Fortran 30 (F90) with Message Passing interface (MPI) and High Performance Fortran (HPF). This improves the maintainability, reusability. and extensibility of software, combined with the high performance of using MPI and the ease of parallel programming provided by HPF. The overhead associated with the object-oriented implementation has only a minor effect on performance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, LANSCE 1, Los Alamos, NM 87545 USA. RP Qiang, J (reprint author), Univ Calif Los Alamos Natl Lab, LANSCE 1, Ms H817, Los Alamos, NM 87545 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 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD DEC 1 PY 2000 VL 133 IS 1 BP 18 EP 33 DI 10.1016/S0010-4655(00)00165-X PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 387NF UT WOS:000166128100003 ER PT J AU Sewards, TV Sewards, MA AF Sewards, TV Sewards, MA TI The awareness of thirst: Proposed neural correlates SO CONSCIOUSNESS AND COGNITION LA English DT Review DE thirst; consciousness; emotional awareness; motivation; synchronous oscillations; periaqueductal gray; cingulate cortex; medial preoptic area; circumventricular organs ID MIDBRAIN PERIAQUEDUCTAL GRAY; LATERAL GENICULATE-NUCLEUS; MEDIAN PREOPTIC NUCLEUS; C-FOS EXPRESSION; MONKEYS MACACA-FASCICULARIS; ANTERIOR CINGULATE CORTEX; ANGIOTENSIN-II; RAT-BRAIN; SUBFORNICAL ORGAN; VISUAL-CORTEX AB The neural and endocrine bases of the generation of thirst are reviewed. Based on this review, a hierarchical system of neural structures that regulate water conservation and acquisition is proposed. The system includes primary sensory-receptive areas. secondary sensory structures (circumventricular organs), which detect levels of hormones. including angiotensin II and vasopressin, which are involved in generating thirst: preoptic and hypothalamic structures; and an area within the ventrolateral quadrant of the periaqueductal gray matter. Hodological and other data are used to determine the hierarchical organization of the system. Based on studies of the effects of lesions to various structures within the hierarchy of the system, it is proposed that the awareness of thirst in rodents is either entirely or predominantly due to neuronal activities in a subsection of the ventrolateral periaqueductal gray matter. It is also hypothesized that the awareness of thirst in primates is due to neuronal activities in both the ventrolateral periaqueductal gray and in a region within the medial prefrontal and anterior cingulate cortex. (C) 2000 Academic Press. C1 Sandia Res Ctr, Placitas, NM 87043 USA. RP Sewards, TV (reprint author), Sandia Res Ctr, 21 Perdiz Canyon Rd, Placitas, NM 87043 USA. NR 150 TC 20 Z9 20 U1 1 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1053-8100 J9 CONSCIOUS COGN JI Conscious. Cogn. PD DEC PY 2000 VL 9 IS 4 BP 463 EP 487 DI 10.1006/ccog.2000.0462 PG 25 WC Psychology, Experimental SC Psychology GA 393TC UT WOS:000166484900001 PM 11150217 ER PT J AU Riitters, K Wickham, J O'Neill, R Jones, B Smith, E AF Riitters, K Wickham, J O'Neill, R Jones, B Smith, E TI Global-scale patterns of forest fragmentation SO CONSERVATION ECOLOGY LA English DT Article DE biogeography; edge effect; forest fragmentation; geographic information systems; global patterns; land-cover map; landscape ecology; modeling; perforated forest; remote sensing; satellite imagery; spatial pattern ID LANDSCAPE; DEFORESTATION; ECOLOGY; AMAZON AB We report an analysis of forest fragmentation based on l-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km (2) (9 x 9 pixels, "small" scale) to 59,049 km (2) (243 x 243 pixels, "large" scale) were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined) from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents, there were significant differences among individual forest types. Tropical rain forest fragmentation was most severe in North America and least severe in Europe-Asia. Forest types with a high percentage of perforated conditions were mainly in North America (five types) and Europe-Asia (four types), in both temperate and subtropical regions. Transitional and patch conditions were most common in 11 types, of which only a few would be considered as "naturally patchy" (e.g., dry woodland). The five forest types with the highest percentage of interior conditions were in North America; in decreasing order, they were cool rain forest, coniferous, conifer boreal, cool mixed, and cool broadleaf. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Riitters, K (reprint author), US Forest Serv, So Res Stn, 3041 Cornwallis Rd,POB 12254, Res Triangle Pk, NC 27709 USA. NR 27 TC 132 Z9 154 U1 2 U2 59 PU RESILIENCE ALLIANCE PI WOLFVILLE PA ACADIA UNIV, BIOLOGY DEPT, WOLFVILLE, NS B0P 1X0, CANADA SN 1195-5449 J9 CONSERV ECOL JI Conserv. Ecol. PD DEC PY 2000 VL 4 IS 2 AR 3 PG 30 WC Ecology SC Environmental Sciences & Ecology GA 411HQ UT WOS:000167492900005 ER PT J AU Reed, MJ Candela, PA Piccoli, PM AF Reed, MJ Candela, PA Piccoli, PM TI The distribution of rare earth elements between monzogranitic melt and the aqueous volatile phase in experimental investigations at 800 degrees C and 200 MPa SO CONTRIBUTIONS TO MINERALOGY AND PETROLOGY LA English DT Article ID SILICATE MELTS; ORE-DEPOSITS; SYSTEMS; WATER; SOLUBILITY; COPPER; H2O; ENVIRONMENTS; MOLYBDENUM; PARTITION AB The partitioning of the rare earth elements between a peraluminous monzogranitic melt and a chloride-bearing, sulfur- and carbon dioxide-free, aqueous volatile phase was examined experimentally as a function of chloride and major element concentrations at 800 degreesC and 200 MPa. The light rare earth elements (e.g. La, Ce) partition into the aqueous volatile phase to a greater extent than the heavy rare earth elements (e.g. Yb, Lu). Distribution of the rare earth elements and the major elements H, Na, K, Ca, and Al between the melt phase (mp) and aqueous volatile phase tag) is a function of the chlorine concentration in the system, and our data are consistent with the rare earth and major elements occurring as chloride complexes in the aqueous Volatile phase. Apparent equilibrium constants for experiments, at 800 degreesC and 200 MPa, K-REE1Na('aq/mp), expressed as the ratio as the ratio of the concentration of a given rare earth element in the aqueous volatile phase to the concentration of the same element in the melt phase, divided by the cubed ratio of sodium in the aqueous volatile phase to the concentration of sodium in the melt phase, decrease systematically with increasing atomic number from K-La,Na('aq/mp) = 0.41(+/-0.03) to K-Lu,Na('aq/mp) = 0.11(+/-0.01), except for Eu. These experimentally derived apparent equilibrium constants for the rare earth elements can be used in a numerical simulation of magmatic volatile exsolution. The simulation gave results consistent with the elemental distribution in the potassic alteration zone of a deep porphyry copper deposit, but higher concentrations of heavy rare earth elements are released into the magmatic aqueous solution than are captured in the secondary mineralization. C1 Univ Maryland, Dept Geol, Lab Mineral Deposits Res, College Pk, MD 20742 USA. RP Reed, MJ (reprint author), US DOE, Off Geothermal & Wind Technol, Washington, DC 20585 USA. NR 38 TC 37 Z9 40 U1 0 U2 18 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0010-7999 J9 CONTRIB MINERAL PETR JI Contrib. Mineral. Petrol. PD DEC PY 2000 VL 140 IS 2 BP 251 EP 262 DI 10.1007/s004100000182 PG 12 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 388CH UT WOS:000166159500008 ER PT J AU McGee, MW France, DM Sanders, RC AF McGee, MW France, DM Sanders, RC TI Calibration of saturated liquid helium weir flowmeter at Fermilab SO CRYOGENICS LA English DT Article DE two-phase helium flow; weir flowmeter; liquid helium AB The flow of saturated liquid helium at 4.2 K was studied in a unique weir flowmeter mounted inside a duct. The objective was to develop a calibration for helium flow rate in the weir, and thereby, making it a viable flowmeter. The weir flowmeter was tested in a liquid helium system at Fermi National Laboratory used for cooling the superconducting magnets in the experimental areas of the site. Unlike for open channel weir devices, the calibration of this flowmeter was influenced by both the liquid flow through the weir notch and the vapor flow over it. The results of this study and the calibration are presented taking into account effects of both liquid and vapor. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Illinois, Dept Mech Engn, Chicago, IL 60607 USA. RP McGee, MW (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD DEC PY 2000 VL 40 IS 12 BP 759 EP 768 DI 10.1016/S0011-2275(01)00029-7 PG 10 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA 433GZ UT WOS:000168753000002 ER PT J AU Celniker, SE AF Celniker, SE TI The Drosophila genome SO CURRENT OPINION IN GENETICS & DEVELOPMENT LA English DT Article ID PHYSICAL MAP; GENE; MELANOGASTER; P53; DNA; IDENTIFICATION; SUPPRESSION; SEQUENCE; HOMOLOG; DISEASE AB The past year has been a spectacular one for Drosophila research. The sequencing and annotation of the Drosophila melanogaster genome has allowed a comprehensive analysis of the first three eukaryotes to be sequenced - yeast, worm and fly - including an analysis of the fly's influences as a model for the study of human disease. This year has also seen the initiation of a full-length cDNA sequencing project and the first analysis of Drosophila development using high-density DNA microarrays containing several thousand Drosophila genes. For the first time homologous recombination has been demonstrated in flies and targeted gene disruptions may not be far off. C1 Lawrence Berkeley Natl Lab, Berkeley Drosophila Genome Project, Berkeley, CA 94720 USA. RP Lawrence Berkeley Natl Lab, Berkeley Drosophila Genome Project, Berkeley, CA 94720 USA. EM celniker@bdgp.lbl.gov FU NHGRI NIH HHS [P50HG00750] NR 45 TC 6 Z9 7 U1 0 U2 4 PU CURRENT BIOLOGY LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0959-437X EI 1879-0380 J9 CURR OPIN GENET DEV JI Curr. Opin. Genet. Dev. PD DEC PY 2000 VL 10 IS 6 BP 612 EP 616 DI 10.1016/S0959-437X(00)00140-4 PG 5 WC Cell Biology; Genetics & Heredity SC Cell Biology; Genetics & Heredity GA 380UP UT WOS:000165722100005 PM 11088010 ER PT J AU Helander, P Fielding, SJ Cohen, RH Ryutov, DD AF Helander, P Fielding, SJ Cohen, RH Ryutov, DD TI Electric biasing of the divertor tiles in COMPASS-D SO CZECHOSLOVAK JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 3rd Europhysics Workshop on the Role of Electric Fields in Plasma Confinement and Exhaust CY JUN 18-19, 2000 CL BUDAPEST, HUNGARY SP Inst Plasma Phys, Assoc EURATOM/IPP CR, Acad Sci Czech Republ ID PLASMA AB It has been suggested that by electrically biasing the divertor tiles in a tokamak, one could create a toroidally-asymmetric potential structure in the scrape-off layer (SOL) plasma. The resulting E x B convective motion should increase the plasma transport in the SOL and thereby reduce the heat load on the divertor plates. This paper describes plans for such experiments on COMPASS-D and preliminary theoretical modelling. The COMPASS-D divertor target consists of 24 graphite tiled toroidal segments. The inner and outer strike point tiles on all these segments will be insulated from each other, and cabling will be installed to allow for biasing of individual tiles in any combination. Theoretical analysis suggests that the electrostatic potential perturbations caused by the biasing will be confined to the divertor region below the X-point, and that substantial SOL broadening can be achieved by applying modest voltages. Aside from active control of SOL transport, it is hoped that the biasing will be useful to probe other divertor and SOL physics issues. C1 EURATOM, UKAEA Fus Assoc, Culham Sci Ctr, Abingdon, Oxon, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Helander, P (reprint author), EURATOM, UKAEA Fus Assoc, Culham Sci Ctr, Abingdon, Oxon, England. NR 9 TC 3 Z9 3 U1 2 U2 3 PU INST PHYSICS ACAD SCI CZECH REPUBLIC PI PRAGUE PA NA SLOVANCE 2, PRAGUE 182 21, CZECH REPUBLIC SN 0011-4626 J9 CZECH J PHYS JI Czech. J. Phys. PD DEC PY 2000 VL 50 IS 12 BP 1421 EP 1430 DI 10.1023/A:1022851714099 PG 10 WC Physics, Multidisciplinary SC Physics GA 393CG UT WOS:000166451200004 ER PT J AU Pedrosa, MA Hidalgo, C Lopez-Fraguas, A Van Milligen, BP Balbin, R Jimenez, JA Sanchez, E Castellano, J Garcia, L Carreras, BA Lynch, VE AF Pedrosa, MA Hidalgo, C Lopez-Fraguas, A Van Milligen, BP Balbin, R Jimenez, JA Sanchez, E Castellano, J Garcia, L Carreras, BA Lynch, VE CA TJ-II Team TI Role of rational surfaces on fluctuations and transport in the plasma edge of the TJ-II stellarator SO CZECHOSLOVAK JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 3rd Europhysics Workshop on the Role of Electric Fields in Plasma Confinement and Exhaust CY JUN 18-19, 2000 CL BUDAPEST, HUNGARY SP Inst Plasma Phys, Assoc EURATOM/IPP CR, Acad Sci Czech Republ ID MAGNETIC CONFINEMENT DEVICES; POLOIDAL FLOW GENERATION; ANOMALOUS TRANSPORT; VELOCITY-SHEAR; H TRANSITION; TURBULENCE; TOKAMAKS; BIFURCATION; PROGRESS; ROTATION AB It has been shown that transport barriers in toroidal magnetically confined plasmas tend to be linked to regions of unique magnetic topology such as the location of a minimum in the safety factor, rational surfaces or the boundary between closed and open flux surfaces. In the absence of E x B sheared flows, fluctuations are expected to show maximum amplitude near rational surfaces, and plasma confinement might tend to deteriorate. On the other hand, if the generation of E x B sheared flows were linked to low order rational surfaces, these would be beneficial for confinement. Experimental evidence of E x B sheared flows linked to rational surfaces has been obtained in the plasma edge region of the TJ-II stellarator. C1 EURATOM Assoc, CIEMAT, Lab Nacl Fus Confinamiento Magnet, Madrid 28040, Spain. Univ Carlos III Madrid, Madrid 28911, Spain. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Pedrosa, MA (reprint author), EURATOM Assoc, CIEMAT, Lab Nacl Fus Confinamiento Magnet, Madrid 28040, Spain. RI Sanchez, Edilberto/D-4620-2009; Lopez-Fraguas, Antonio/L-8104-2014; Lynch, Vickie/J-4647-2012; Garcia, Luis/A-5344-2015; van Milligen, Boudewijn/H-5121-2015; Jimenez, Juan/A-5245-2017; Balbin, Rosa/F-8210-2010; Hidalgo, Carlos/H-6109-2015 OI Sanchez, Edilberto/0000-0003-1062-7870; Lopez-Fraguas, Antonio/0000-0002-0277-8137; Lynch, Vickie/0000-0002-5836-7636; Garcia, Luis/0000-0002-0492-7466; van Milligen, Boudewijn/0000-0001-5344-6274; Jimenez, Juan/0000-0003-3453-2470; Balbin, Rosa/0000-0001-5231-1300; NR 25 TC 8 Z9 8 U1 0 U2 1 PU INST PHYSICS ACAD SCI CZECH REPUBLIC PI PRAGUE PA NA SLOVANCE 2, PRAGUE 182 21, CZECH REPUBLIC SN 0011-4626 J9 CZECH J PHYS JI Czech. J. Phys. PD DEC PY 2000 VL 50 IS 12 BP 1463 EP 1470 DI 10.1023/A:1022859915916 PG 8 WC Physics, Multidisciplinary SC Physics GA 393CG UT WOS:000166451200008 ER PT J AU Cory, D Laflamme, R AF Cory, D Laflamme, R TI Computing with quantum physics - Quantum computing offers great promise for very powerful systems SO DR DOBBS JOURNAL LA English DT Article C1 MIT, Cambridge, MA 02139 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU MILLER FREEMAN, INC PI SAN FRANCISCO PA 600 HARRISON ST,, SAN FRANCISCO, CA 94107 USA SN 1044-789X J9 DR DOBBS J JI Dr. Dobbs J. PD DEC PY 2000 SU S BP 29 EP 32 PG 4 WC Computer Science, Software Engineering SC Computer Science GA 371JW UT WOS:000165176700006 ER PT J AU Smalley, JF Newton, MD Feldberg, SW AF Smalley, JF Newton, MD Feldberg, SW TI An informative subtlety of itemperature-jump or coulostatic responses for surface-attached species SO ELECTROCHEMISTRY COMMUNICATIONS LA English DT Article DE temperature-jump; laser; ILIT; coulostatic; surface-attached redox species; redox capacitance; electron transfer resistance ID ELECTRON-TRANSFER; GOLD AB Theoretical relationships are developed to describe the open-circuit responses associated with the indirect laser-induced temperature-jump (ILIT) method, a method for measuring fast electron-transfer rate constants of surface-attached redox species. The analysis is also applicable to data obtained using the coulostatic charge-injection method. The unique relationship between k(m), the relaxation rate constant for the ILIT (or coulostatic) response, and E-i, the potential at which the system is initially poised, exhibits a surprising sensitivity to the values of k(0), E-i(0') (the standard rate constant and formal potential for the redox couple), alpha (the transfer coefficient in the Butler-Volmer equation) and gamma (a dimensionless parameter which is directly proportional to the total surface concentration of the redox moiety). ILIT data for several examples of surface-attached ferrocene moieties confirm the theoretically predicted k(m) vs E-i behavior. Values of E-i(0') and gamma extracted from the ILIT data agree well with the values obtained from cyclic voltammetric data thereby confirming that the ILIT and cyclic voltammogram (CV) experiments are sampling the same ferrocene population. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Brookhaven Natl Lab, Energy Sci & Technol Dept, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Feldberg, SW (reprint author), Brookhaven Natl Lab, Dept Appl Sci, Bldg 815, Upton, NY 11973 USA. NR 17 TC 18 Z9 18 U1 2 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1388-2481 J9 ELECTROCHEM COMMUN JI Electrochem. Commun. PD DEC PY 2000 VL 2 IS 12 BP 832 EP 838 DI 10.1016/S1388-2481(00)00132-6 PG 7 WC Electrochemistry SC Electrochemistry GA 388WD UT WOS:000166205300005 ER PT J AU Worrell, E Martin, N Price, L AF Worrell, E Martin, N Price, L TI Potentials for energy efficiency improvement in the US cement industry SO ENERGY LA English DT Article AB This paper reports on an in-depth analysis of the US cement industry, identifying cost-effective energy efficiency measures and potentials. Between 1970 and 1997, primary physical energy intensity for cement production (SIC 324) dropped 30%, from 7.9 GJ/t to 5.6 GJ/t, while specific carbon dioxide emissions due to fuel consumption and clinker calcination dropped 17%, from 0.29 tC/tonne to 0.24 tC/tonne. We examined 30 energy-efficient technologies and measures and estimated energy savings, carbon dioxide savings, investment costs, and operation and maintenance costs for each of the measures. We constructed an energy conservation supply curve for the US cement industry which found a total cost-effective energy saving of 11% of 1994 energy use for cement making and a saving of 5% of total 1994 carbon dioxide emissions. Assuming the increased production of blended cement, the technical potential for energy efficiency improvement would not change considerably. However, the cost-effective potential would increase to 18% of total energy use, and carbon dioxide emissions would be reduced by 16%. This demonstrates that the use of blended cements is a key cost-effective strategy for energy efficiency improvement and carbon dioxide emission reductions in the US cement industry. Published by Elsevier Science Ltd. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Energy Anal Dept, Berkeley, CA 94720 USA. RP Worrell, E (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Environm Energy Technol Div, Energy Anal Dept, MS90-4000,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Worrell, Ernst/L-5455-2013 OI Worrell, Ernst/0000-0002-0199-9755 NR 40 TC 114 Z9 119 U1 3 U2 25 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0360-5442 J9 ENERGY JI Energy PD DEC PY 2000 VL 25 IS 12 BP 1189 EP 1214 DI 10.1016/S0360-5442(00)00042-6 PG 26 WC Thermodynamics; Energy & Fuels SC Thermodynamics; Energy & Fuels GA 379NA UT WOS:000165647900003 ER PT J AU Webber, CA Brown, RE Koomey, JG AF Webber, CA Brown, RE Koomey, JG TI Savings estimates for the ENERGY STAR (R) voluntary labeling program SO ENERGY POLICY LA English DT Article AB ENERGY STAR(R) is a voluntary labeling program designed to identify and promote energy-efficient products. Operated jointly by the Environmental Protection Agency (EPA) and the US Department of Energy (DOE), ENERGY STAR labels exist for more than 20 products, spanning office equipment, residential heating and cooling equipment, new homes, commercial and residential lighting, home electronics, and major appliances. We present estimates of the energy, dollar and carbon savings already achieved by the program and provide savings forecasts for several market penetration scenarios for the period 2001-2010. The target market penetration forecast represents our best estimate of future ENERGY STAR savings. It is based on realistic market penetration goals for each of the products. We also provide a forecast under the assumption of 100% market penetration; that is, we assume that all purchasers buy ENERGY STAR-compliant products instead of standard efficiency products throughout the analysis period. Finally, we assess the sensitivity of our target penetration case forecasts to greater or lesser marketing success by EPA and DOE, lower-than-expected future energy prices, and higher or lower rates of carbon emissions by electricity generators. Published by Elsevier Science Ltd. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Webber, CA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Mail Stop 90-4000,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 30 TC 30 Z9 30 U1 1 U2 9 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD DEC PY 2000 VL 28 IS 15 BP 1137 EP 1149 DI 10.1016/S0301-4215(00)00083-5 PG 13 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA 373VW UT WOS:000165311600006 ER PT J AU Holcomb, GR AF Holcomb, GR TI Failure analysis of an HCl gas cylinder valve SO ENGINEERING FAILURE ANALYSIS LA English DT Article DE fouling; dezincification; valve failures AB The fouling failure of an anhydrous HCl gas cylinder valve was investigated after the failure led to an accidental release of HCl gas. It is surmised that water penetrated into the valve by improper purging or valving, and created a severely corrosive environment. The aluminum bronze valve body underwent general corrosion. The corrosion products, primarily nantokite (CuCl), built up within the valve and led to the fouling failure. Dezincification was observed in a leaded nickel silver component of the valve. The Monel 400 Valve stem was intact. The cylinder and valve testing procedures that led to the gas release incident are also examined. Published by Elsevier Science Ltd. C1 US Dept Energy, Albany Res Ctr, Albany, OR 97321 USA. RP Holcomb, GR (reprint author), US Dept Energy, Albany Res Ctr, 1450 Queen Ave SW, Albany, OR 97321 USA. RI Holcomb, Gordon/G-9070-2013 OI Holcomb, Gordon/0000-0003-3542-5319 NR 3 TC 4 Z9 4 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-6307 J9 ENG FAIL ANAL JI Eng. Fail. Anal. PD DEC PY 2000 VL 7 IS 6 BP 403 EP 409 DI 10.1016/S1350-6307(99)00036-9 PG 7 WC Engineering, Mechanical; Materials Science, Characterization & Testing SC Engineering; Materials Science GA 348BN UT WOS:000088964400004 ER PT J AU Stauffer, PH Rosenberg, ND AF Stauffer, PH Rosenberg, ND TI Vapor phase transport at a hillside landfill SO ENVIRONMENTAL & ENGINEERING GEOSCIENCE LA English DT Article DE landfills; vapor phase migration; volatile contaminants ID GAS MIGRATION; METHANE; CONVECTION AB This paper reports the results from a series of two-dimensional, time-dependent simulations of heat and mass transfer through a partially saturated mesa-top landfill in northern New Mexico. Simulations use the finite element approach to solve the governing equations for a problem, wherein air mass, water mass, and energy are conserved. We use a computational grid that maintains complex topographic and stratigraphic boundaries. The 30 m of topographic relief at the site allows atmospheric communication with the subsurface air and water vapor within the mesa. Time-dependent heat and gas generated in the landfill through the decomposition of organic waste provide the main driving forces for vapor phase migration. We show that the magnitude of vapor phase migration is primarily controlled by gas generation source strength, Increased temperature has a secondary effect on vapor phase flux. Flow paths change considerably from pre-landfill to post-landfill conditions. Pre-landfill upflow of air through the mesa with maximum flux of 2 cm/yr is driven by ambient density gradients. Post-landfill gas input reverses the direction of flow beneath the landfill, forcing gas into dry, permeable pathways that lead into the mesa. Vapor advection along high permeability zones beneath the landfill may explain observations of landfill gas found at depth. Post-landfill vapor flux most likely peaked with a maximum flux on the order of 30 m/yr, within the first 20 years since closure. Advective transport of gas below the landfill is shown to dominate during the high productivity phase of gas generation. Transport of landfill gas is shown to be dominated by diffusion when the vapor phase flux falls below 1 to 3 m/yr. Model results suggest that capping the landfill with a low permeability layer could cause the vapor flux to be diverted into the surrounding mesa via dry pathways. C1 Los Alamos Natl Lab, Earth & Environm Sci Div MS F665, Los Alamos, NM 87545 USA. RP Stauffer, PH (reprint author), Los Alamos Natl Lab, Earth & Environm Sci Div MS F665, Los Alamos, NM 87545 USA. OI Stauffer, Philip/0000-0002-6976-221X NR 37 TC 5 Z9 5 U1 1 U2 4 PU GEOLOGICAL SOC AMER, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 1078-7275 J9 ENVIRON ENG GEOSCI JI Environ. Eng. Geosci. PD WIN PY 2000 VL 6 IS 1 BP 71 EP 84 PG 14 WC Engineering, Environmental; Engineering, Geological; Geosciences, Multidisciplinary SC Engineering; Geology GA 346CW UT WOS:000088853900005 ER PT J AU Roh, Y Lee, SY Elless, MP AF Roh, Y Lee, SY Elless, MP TI Characterization of corrosion products in the permeable reactive barriers SO ENVIRONMENTAL GEOLOGY LA English DT Article DE groundwater treatment; iron oxides; trichloroethene; uranium; zero-valent iron ID ZERO-VALENT IRON; SULFATE-REDUCING BACTERIA; GREEN RUST; POURBAIX DIAGRAM; AQUEOUS-MEDIA; GROUNDWATER; HYDROXIDE; REDUCTION; REMEDIATION; MECHANISM AB The impact of geochemical processes and microbial activity has been a major concern for the long-term performance of reactive iron barriers because corrosion products and precipitates during the water treatment with reactive materials will decrease the reactivity and permeability of the iron bed. This study characterizes corrosion products in reactive iron barrier as well as evaluates the effect of the iron corrosion products and precipitates on iron wall performance during contaminated-water treatment under varying conditions. Major phases in the reactive iron barrier include iron oxides, carbonates, iron sulfides, and elemental sulfur, depending on the degree of iron oxidation, groundwater chemistry, and microbial activity. Detailed geochemical and mineralogical characteristics are imperative for long-range predictions of the reactive iron wall performance on water treatment because the surface coating materials reduce the effectiveness of the zero-valent iron media. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Edenspace Syst Corp, Reston, VA 20191 USA. RP Roh, Y (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 37 TC 124 Z9 132 U1 1 U2 41 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0943-0105 J9 ENVIRON GEOL JI Environ. Geol. PD DEC PY 2000 VL 40 IS 1-2 BP 184 EP 194 PG 11 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 386HT UT WOS:000166055700018 ER PT J AU Dufault, R Abelquist, E Crooks, S Demers, D DiBerardinis, L Franklin, T Horowitz, M Petullo, C Sturchio, G AF Dufault, R Abelquist, E Crooks, S Demers, D DiBerardinis, L Franklin, T Horowitz, M Petullo, C Sturchio, G TI Reducing environmental risk associated with laboratory decommissioning and property transfer SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article; Proceedings Paper CT Leadership Conference on Biomedical Research and the Environment CY NOV 01-02, 1999 CL BETHESDA, MARYLAND SP Natl Assoc Physicians Environm, Assoc Higher Educ Facil Officers, US Natl Inst Environm Hlth Sci, W Alton Jones Fdn, Mitchell Kapor Fdn, Shulsky Fdn, Hahn Family Fdn, Baxter Int Inc DE assessment; characterization; decommissioning; decontamination; demolition; environmental; laboratory; liability; remediation; renovation AB The need for more or less space is a common laboratory problem. Solutions may include renovating existing space, leaving or demolishing old space, or acquiring new space or property for building. All of these options carry potential environmental risk. Such risk can be the result of activities related to the laboratory facility or property (e.g., asbestos, underground storage tanks, lead paint), or the research associated with it (e.g., radioactive, microbiological, and chemical contamination). Regardless of the option chosen to solve the space problem, the potential environmental risk must be mitigated and the laboratory space and/or property must be decommissioned or rendered safe prior to any renovation, demolition, or property transfer activities. Not mitigating the environmental risk through a decommissioning process can incur significant financial liability for any costs associated with future decommissioning cleanup activities. Out of necessity, a functioning system, environmental due diligence auditing, has evolved over time to assess environmental risk and reduce associated financial liability. This system involves a 4-phase approach to identify, document, manage, and clean up areas of environmental concern or liability, including contamination. Environmental due diligence auditing includes a) historical site assessment, b) characterization assessment, c) remedial effort and d) final status survey. General practice standards from the American Society for Testing and Materials are available for conducting the first two phases. However, standards have not yet been developed for conducting the third and final phases of the environmental due diligence auditing process. Individuals involved in laboratory decommissioning work in the biomedical research industry consider this a key weakness. C1 US FDA, Div Facilities Planning Engn & Safety, Rockville, MD 20857 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN USA. Glaxo Wellcome Inc, Res Triangle Pk, NC 27709 USA. MIT, Cambridge, MA 02139 USA. USDA, Beltsville, MD USA. Analog Devices Inc, Cambridge, MA USA. US EPA, Las Vegas, NV 89193 USA. Merck Res Labs, Rahway, NJ USA. RP Dufault, R (reprint author), US FDA, Div Facilities Planning Engn & Safety, HFA-34,5630 Fishers Lane, Rockville, MD 20857 USA. NR 18 TC 1 Z9 1 U1 0 U2 1 PU US DEPT HEALTH HUMAN SCIENCES PUBLIC HEALTH SCIENCE PI RES TRIANGLE PK PA NATL INST HEALTH, NATL INST ENVIRONMENTAL HEALTH SCIENCES, PO BOX 12233, RES TRIANGLE PK, NC 27709-2233 USA SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD DEC PY 2000 VL 108 SU 6 BP 1015 EP 1022 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 386TP UT WOS:000166077900010 PM 11121365 ER PT J AU Bhaduri, B Harbor, J Engel, B Grove, M AF Bhaduri, B Harbor, J Engel, B Grove, M TI Assessing watershed-scale, long-term hydrologic impacts of land-use change using a GIS-NPS model SO ENVIRONMENTAL MANAGEMENT LA English DT Article DE hydrology; geographic information system; nonpoint source pollution; modeling; water resources; watershed ID GEOGRAPHIC INFORMATION-SYSTEMS; NONPOINT-SOURCE POLLUTION; URBAN WATERSHEDS; QUALITY; POLLUTANTS; RUNOFF AB Land-use change, dominated by an increase in urban/impervious areas, has a significant impact on water resources. This includes impacts on nonpoint source (NPS) pollution, which is the leading cause of degraded water quality in the United States. Traditional hydrologic models focus on estimating peak discharges and NPS pollution from high-magnitude, episodic storms and successfully address short-term, local-scale surface water management issues. However, run-off from small, low-frequency storms dominates long-term hydrologic impacts, and existing hydrologic models are usually of limited use in assessing the long-term impacts of land-use change. A long-term hydrologic impact assess ment (L-THIA) model has been developed using the curve number (CN) method. Long-term climatic records are used in combination with soils and land-use information to calculate average annual runoff and NPS pollution at a watershed scale. The model is linked to a geographic information system (GIS) for convenient generation and management of model input and output data, and advanced visualization of model results. The L-THIA/NPS GIS model was applied to the Little Eagle Creek (LEC) watershed near Indianapolis, Indiana, USA. Historical land-use scenarios for 1973, 1984, and 1991 were analyzed to track land-use change in the watershed and to assess impacts on annual average runoff and NPS pollution from the watershed and its five subbasins. For the entire watershed between 1973 and 1991, an 18% increase in urban or impervious areas resulted in an estimated 80% increase in annual average runoff volume and estimated increases of more than 50% in annual average loads for lead, copper, and zinc. Estimated nutrient (nitrogen and phosphorus) loads decreased by 15% mainly because of loss of agricultural areas. The L-THIA/NPS GIS model is a powerful tool for identifying environmentally sensitive areas in terms of NPS pollution potential and for evaluating alternative land use scenarios for NPS pollution management. C1 GIS Technol Grp, Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47907 USA. Purdue Univ, Dept Agr & Biol Engn, W Lafayette, IN 47907 USA. RP Bhaduri, B (reprint author), GIS Technol Grp, Oak Ridge Natl Lab, POB 2008,MS 6237, Oak Ridge, TN 37831 USA. OI Harbor, Jonathan/0000-0001-5129-0229 NR 52 TC 138 Z9 169 U1 6 U2 80 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0364-152X J9 ENVIRON MANAGE JI Environ. Manage. PD DEC PY 2000 VL 26 IS 6 BP 643 EP 658 DI 10.1007/s002670010122 PG 16 WC Environmental Sciences SC Environmental Sciences & Ecology GA 368HQ UT WOS:000090112000006 PM 11029115 ER PT J AU Peters, AJ Lane, DA Gundel, LA Northcott, GL Jones, KC AF Peters, AJ Lane, DA Gundel, LA Northcott, GL Jones, KC TI A comparison of high volume and diffusion denuder samplers for measuring semivolatile organic compounds in the atmosphere SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; POLYCHLORINATED-BIPHENYLS; GAS-PHASE; AIR; PARTICLE; URBAN; PCBS; PERFORMANCE; DESIGN; PAHS AB A detailed comparison of two inherently different ambient air samplers has been conducted to fully characterize and compare their performance in sampling and measuring the partitioning of a suite of 29 semivolatile organic compounds (SVOCs), A high volume air sampler (hi-vol) utilizing polyurethane foam (PUF) adsorbent for vapor-phase trapping and an annular diffusion denuder sampler were operated concurrently. Sampling artifacts were observed and can be related to the physicochemical properties of the analytes and the designs of the samplers. The results suggest that high volume air samplers equipped with PUF are unsuitable for measuring those organochlorine compounds and 2- and 3-ring PAHs which have subcooled liquid vapor pressures (p degrees (L)) greater than ca. 0.2 Pa (log[p degrees (L)] = -0.7), owing to their breakthrough on PUF sampling media at relatively low sample volumes (170 m(3)) and ambient temperatures typical of temperate regions (mean = 11 degreesC, max = 18 degreesC). Theoretical calculations of breakthrough volumes for SVOCs on PUF are presented and in most cases these successfully predict observed behavior. The denuder sampler is more efficient at measuring the relatively volatile SVOCs. For total SVOC measurements the hi-vol and denuder were in good agreement for those compounds which were efficiently sampled, and the denuder yielded total SVOC concentrations which:differed by a mean factor of 1.2 relative to those obtained with the hi-vol sampler, The hi-vol sampler provides good agreement with the Junge-Pankow model for partitioning of the relatively less volatile PAHs (log[p degrees (L)]< -3), though the fraction of the PCBs in the particle-phase is underestimated. The results from the diffusion denuder indicate that for the more volatile SVOCs (log[p(L)] > -3), particulate loadings are overestimated with respect to the Junge-Pankow model, and for less volatile SVOCs, particulate loadings tend to be underestimated. An important observation is that the results from the denuder indicate that PCBs may he adsorbed on atmospheric particulate matter to a similar degree as PAHs. C1 Univ Lancaster, Inst Environm & Nat Sci, Dept Environm Sci, Lancaster LA1 4YQ, England. Environm Canada, Downsview, ON M3H 5T4, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Peters, AJ (reprint author), NERC, Ctr Ecol & Hydrol, Winfrith Technol Ctr, Dorchester DT2 8ZD, England. RI Jones, Kevin/F-4296-2014; OI Jones, Kevin Christopher/0000-0001-7108-9776 NR 19 TC 75 Z9 77 U1 0 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD DEC 1 PY 2000 VL 34 IS 23 BP 5001 EP 5006 DI 10.1021/es000056t PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 378EN UT WOS:000165572200039 ER PT J AU Spalding, BP AF Spalding, BP TI Volatility and extractability of strontium-85, cesium-134; cobalt-57, and uranium after heating hardened Portland cement paste SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CARBONATION; SOILS AB The objective of this preliminary investigation is to determine the effect of heating hardened Portland cement paste (the cementitious component of concrete) in aiding the removal of common radionuclide contaminants including Cs-137, Sr-90, Co-60, and U. Direct volatilization of radionuclides during heating as well as subsequent behaviors during extractions were established over a range of temperatures up to the melting point of Portland cement paste. Techniques for spiking pulverized Portland cement paste with shorter-lived radioisotopes (Cs-134, Sr-85, and Co-57) and U were developed using gamma-ray spectroscopy to measure their activity nondestructively before and after heating. An extraction procedure (employing five sequential extractions each with water, followed by 0.1 N CaCl2, followed by 0.2 N HCl) for pulverized but fully hydrated Portland cement paste was adapted to contrast behaviors after thermal treatments. Complete volatility of Cs-134 was observed at temperatures of 1200 degreesC or greater. Thus, decontamination of Cs-137 from cement paste would be feasible by direct heating. However, no volatility of other radionuclides was observed, and, thus, their potential for facilitated decontamination will likely depend pn their extraction behavior following thermal perturbation. Both Cs-134 and Sr-85 were readily removed from cement paste during initial water-based extractions for final temperatures <800 C. In contrast, both Co-57 and U exhibited negligible extractability into either water or 0.1 N CaCl2 probably resulting from their precipitation as hydroxides in the highly alkaline Portland cement paste extracts where pHs were usually greater than 10. The release of both these radionuclides was delayed until sequential 0.2 N HCl extracts decreased the pH below 4. Significant patterns in the extraction behaviors of all radionuclides with temperature were observed in ranges where significant mineral alterations are known to occur. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Spalding, BP (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 29 TC 13 Z9 13 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD DEC 1 PY 2000 VL 34 IS 23 BP 5051 EP 5058 DI 10.1021/es001396h PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 378EN UT WOS:000165572200046 ER EF