FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Whalley, SA Murray, JM Brown, D Webster, GJM Emery, VC Dusheiko, GH Perelson, AS AF Whalley, SA Murray, JM Brown, D Webster, GJM Emery, VC Dusheiko, GH Perelson, AS TI The kinetics of acute hepatitis B virus infection in humans. SO HEPATOLOGY LA English DT Meeting Abstract C1 Royal Free Hosp, London NW3 2QG, England. Univ New S Wales, Sydney, NSW, Australia. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RI Murray, John/B-5481-2009 OI Murray, John/0000-0001-9314-2283 NR 0 TC 0 Z9 0 U1 0 U2 0 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 USA SN 0270-9139 J9 HEPATOLOGY JI Hepatology PD OCT PY 2000 VL 32 IS 4 MA 1145 BP 446A EP 446A PN 2 PG 1 WC Gastroenterology & Hepatology SC Gastroenterology & Hepatology GA 359PZ UT WOS:000089622401131 ER PT J AU Jones, DS AF Jones, DS TI Radiological benchmarks for effects on aquatic biota at the Oak Ridge reservation SO HUMAN AND ECOLOGICAL RISK ASSESSMENT LA English DT Article DE radionuclides; screening values; ecological risk assessment; water; sediment; and fish AB Radiological benchmarks for aquatic biota were developed for use at the U.S. Department of Energy's Oak Ridge Reservation as screening values to determine the spatial extent of potential ecological effects and to identify the need for additional site-specific investigation. The Point Source Dose Distribution approach was used to calculate water and sediment activities for selected radionuclides that result in a total dose rate to small and large fish of 1 Rad d(-1), which is the National Council on Radiation Protection and Measurements' recommended acceptable dose rate to natural populations of aquatic biota. These screening values incorporate internal and external exposures from parent isotopes and all short-lived daughter products. They also include exposures from all major alpha, beta, and gamma emissions for each isotope. Unlike exposures to chemicals, exposures to radionuclides are expressed as the dose rate received by the organism. Dose rates that account for the biological effects to the organism are additive. If the total dose rate from all radionuclides and pathways exceeds a recommended acceptable dose rate, further analysis is needed to determine the hazards posed by radionuclides. If, however, the total dose rate falls below an acceptable dose rate, radionuclides may be eliminated from further study. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Jones, DS (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 25 TC 3 Z9 4 U1 0 U2 0 PU CRC PRESS LLC PI BOCA RATON PA 2000 CORPORATE BLVD NW, JOURNALS CUSTOMER SERVICE, BOCA RATON, FL 33431 USA SN 1080-7039 J9 HUM ECOL RISK ASSESS JI Hum. Ecol. Risk Assess. PD OCT PY 2000 VL 6 IS 5 BP 789 EP 807 DI 10.1080/10807030091124202 PG 19 WC Biodiversity Conservation; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 374BU UT WOS:000165325200007 ER PT J AU Hartmann, HM Monette, FA Avci, HI AF Hartmann, HM Monette, FA Avci, HI TI Overview of toxicity data and risk assessment methods for evaluating the chemical effects of depleted uranium compounds SO HUMAN AND ECOLOGICAL RISK ASSESSMENT LA English DT Article DE depleted uranium; chemical toxicity; acute exposures; chronic exposures; health effects; risk assessment ID INHALATION AB In the United States, depleted uranium is handled or used in several chemical forms by both governmental agencies and private industry (primarily companies producing and machining depleted uranium metal for military applications). Human exposure can occur as a result of handling these compounds, routine low-level effluent releases to the environment from processing facilities, or materials being accidentally released from storage locations or during processing or transportation. Exposure to uranium can result in both chemical and radiological toxicity, but in most instances chemical toxicity is of greater concern. This article discusses the chemical toxic effects from human exposure to depleted uranium compounds that are likely to be handled during the long-term management and use of depleted uranium hexafluoride (UF,) inventories in the United States. It also reviews representative publications in the toxicological literature to establish appropriate reference values for risk assessments. Methods are described for evaluating chemical toxicity caused by chronic low-level exposure and acute exposure. Example risk evaluations are provided for illustration. Preliminary results indicate that chemical effects of chronic exposure to uranium compounds under normal operating conditions would be negligibly small. Results also show that acute exposures under certain accident conditions could cause adverse chemical effects among the populations exposed. C1 Argonne Natl Lab, Environm Assessment Div, Argonne, IL 60439 USA. RP Hartmann, HM (reprint author), Argonne Natl Lab, Environm Assessment Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 58 TC 28 Z9 29 U1 1 U2 11 PU CRC PRESS LLC PI BOCA RATON PA 2000 CORPORATE BLVD NW, JOURNALS CUSTOMER SERVICE, BOCA RATON, FL 33431 USA SN 1080-7039 J9 HUM ECOL RISK ASSESS JI Hum. Ecol. Risk Assess. PD OCT PY 2000 VL 6 IS 5 BP 851 EP 874 DI 10.1080/10807030091124239 PG 24 WC Biodiversity Conservation; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 374BU UT WOS:000165325200010 ER PT J AU Hazucha, P Svensson, C Wender, SA AF Hazucha, P Svensson, C Wender, SA TI Cosmic-ray soft error rate characterization of a standard 0.6-mu m CMOS process SO IEEE JOURNAL OF SOLID-STATE CIRCUITS LA English DT Article DE circuit reliability; integrated circuit design; manufacturing process characterization; memory testing; particle beams; single event upset; soft error rate ID SINGLE-EVENT UPSETS; MEMORIES AB Cosmic-ray soft errors from ground le, el to aircraft flight altitudes are caused mainly by neutrons. We derived an empirical model for estimation of soft error rate (SER). Test circuits were fabricated in a standard 0.6-mu m CMOS process. The neutron SER dependence on the critical charge and supply voltage was measured. Time constants of the noise current were extracted from the measurements and compared with device simulations in three dimensions. The empirical model was calibrated and verified by independent SER measurements. The model is capable of predicting cosmic-ray neutron SER of any circuit manufactured in the same process as the test circuits. We predicted SER of a static memory cell. C1 Linkoping Univ, S-58183 Linkoping, Sweden. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hazucha, P (reprint author), Linkoping Univ, S-58183 Linkoping, Sweden. NR 18 TC 53 Z9 54 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9200 J9 IEEE J SOLID-ST CIRC JI IEEE J. Solid-State Circuit PD OCT PY 2000 VL 35 IS 10 BP 1422 EP 1429 DI 10.1109/4.871318 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 362LA UT WOS:000089778400006 ER PT J AU Reginato, LL Mangano, JA AF Reginato, LL Mangano, JA TI Memorial tribute to Dr. Daniel Birx (1955-2000) SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Biographical-Item C1 Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Sci Res Lab Inc, Arlington, VA 22209 USA. RP Reginato, LL (reprint author), Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1312 EP 1313 DI 10.1109/TPS.2000.901188 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000001 ER PT J AU Kirbie, HC Sampayan, S AF Kirbie, HC Sampayan, S TI Special issue on pulsed power science & technology SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Editorial Material C1 Siemens Med Syst Inc, Concord, CA 94520 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kirbie, HC (reprint author), Siemens Med Syst Inc, Concord, CA 94520 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1314 EP 1315 DI 10.1109/TPS.2000.901189 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000002 ER PT J AU Smith, DL Hammon, J Wilson, JM Harjes, HC Moore, WBS AF Smith, DL Hammon, J Wilson, JM Harjes, HC Moore, WBS TI FANTM: First article NIF test module SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE arc; capacitor; circuit simulation; electrode erosion; fault diagnosis; flashlamp; gain coefficient; inductor; power conditioning; power distribution cables; spark gap AB Designing and developing the 1.7- to 2.1-MJ power conditioning system (PCS) that will power the flashlamps of the main and power amplifiers for the National Ignition Facility (NIF) lasers is one of several responsibilities assumed by Sandia National Laboratories (SNL) and Maxwell Physics International in support of the NIF Project, The NIF is currently being constructed at Lawrence Livermore National Laboratories (LLNL), The test facility that evolved over three gears to satisfy the project requirements is called the First Article NIF Test Module (FANTM). It was built at SNL and operated for about 17 000 shots to demonstrate component performance expectations over the lifetime of NIF. ii few modules similar to the one shown in Fig, 1 will be used initially in the amplifier test phase of the project. The final NEF system mill require at least 192 modules in the four capacitor bays, This paper briefly summarizes the final design of the FANTM facility and compares its performance with the predictions of circuit simulations for both normal operation and fault-mode response. Applying both the measured and modeled power pulse waveforms as input to a LLNL amplifier gain code indicates that the 20-capacitor PCS can satisfy the NDF requirement for an average gain coefficient of 5.00%/cm and can exceed 5.20 %/cm with 24 capacitors. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Maxwell Phys Int, San Leandro, CA 94577 USA. KTech Corp, Albuquerque, NM 87106 USA. RP Smith, DL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 5 TC 12 Z9 13 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1316 EP 1323 DI 10.1109/27.901190 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000003 ER PT J AU Davis, HA Ballard, EO Elizondo, JM Gribble, RF Nielsen, KE Parker, JV Parsons, WM AF Davis, HA Ballard, EO Elizondo, JM Gribble, RF Nielsen, KE Parker, JV Parsons, WM TI The Atlas power-flow system - A status report SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE material testing; plasmas; pulse power systems; transmission lines AB Atlas is a high-energy, pulsed-power facility under development to study materials properties and hydrodynamics under extreme conditions. Atlas will implode heavy liner loads (m similar to 45 gm) with a peak current of 37-32 MA delivered in 4 I-is, and it is energized by 96, 240-kV Marx generators storing a total of 23 MJ, The power-flow system transports current from the Marx generators to the load. It includes a load protection switch to protect the load in case of a prefire; 24 oil-insulated, vertically oriented, radially converging, triplate transmission lines; a transition region that couples the transmission lines to the power-flow channel; and a radially converging, dielectric-insulated, horizontal and conical? power-flow channel. Proposed experiments, the design of the power-flow system, test results, and status are presented. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Honeywell Inc, Albuquerque, NM 87185 USA. Sumner Associates Inc, Santa Fe, NM 87501 USA. RP Davis, HA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 1 Z9 1 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1405 EP 1413 DI 10.1109/27.901206 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000019 ER PT J AU Turchi, PJ AF Turchi, PJ TI Problems and prospects for microsecond pulsed power above ten megamperes SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE megampere; pulsed power ID PLASMA; COMPRESSION AB Systems, such as Shiva Star, Atlas, and magnetic-flux compression generators (MCGs), that can deliver several mega joules at currents above 10 MA offer the opportunity for many interesting experiments in controlled fusion technology and basic material dynamics. Typical current rise-times of a few microseconds result, even with low inductance (<20 nH) circuitry, because several megajoules are delivered at less than 200 kV. This means that conductor surfaces can move significantly relative to the skin-layer thickness, and surface plasmas can interfere with power flow. Success with such multimegampere technology, therefore, requires considerable attention to the detailed design of joints and conductor surfaces. This paper discusses these and other design considerations. It also describes opportunities enabled by operation above 10 MA. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Turchi, PJ (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 16 TC 7 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1414 EP 1421 DI 10.1109/27.901207 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000020 ER PT J AU Golub, TA Volkov, NB Spielman, RB Gondarenko, NA AF Golub, TA Volkov, NB Spielman, RB Gondarenko, NA TI The effect of an initial load twist on Rayleigh-Taylor instability growth and X-ray radiation of wire-array Z-pinches SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE implosion simulations; Z-pinch ID MODEL AB Initially twisted multiwire Z-pinch loads (Volkov et al. 1998; Golub, 1999) are expected to significantly improve the performance of these X-ray sources. A model based on the self-consistent simulation of the dynamics of a twisted plasma shell and the development of Rayleigh-Taylor (RT) perturbations on a plasma surface is proposed to quantitatively study the effect of various physical factors on the generation of X-rays. The model provides us with a tool for the analysis of processes that occur during the implosion of the plasma-shell-wire-fore system. We plan for the RT perturbations to break through the plasma shell at the moment when the internal radius of a shell becomes zero, where the greatest possible values of kinetic energy and S-rag radiation power ought to be obtained. The results of numerical simulations for the Sandia National Laboratories' Z-generator are presented and discussed. C1 GNG Enterprises Inc, Springfield, VA 22150 USA. Russian Acad Sci, Inst Electrophys, Ekaterinburg, Russia. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Maryland, Inst Plasma Res, College Pk, MD 20742 USA. RP Golub, TA (reprint author), GNG Enterprises Inc, Springfield, VA 22150 USA. NR 12 TC 5 Z9 5 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1422 EP 1426 DI 10.1109/27.901208 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000021 ER PT J AU Rosenthal, SE Desjarlais, MP Spielman, RB Stygar, WA Asay, JR Douglas, MR Hall, CA Frese, MH Morse, RL Reisman, DB AF Rosenthal, SE Desjarlais, MP Spielman, RB Stygar, WA Asay, JR Douglas, MR Hall, CA Frese, MH Morse, RL Reisman, DB TI MHD modeling of conductors at ultrahigh current density SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE conductor hydrodynamics; electrical conductivity; magnetic field diffusion ID CONDUCTIVITY; TRANSPORT; PLASMAS AB In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator (Albuquerque, NM) we have revisited a problem first described in detail by Heinz Knoepfel [1], Unlike the l-Tesla MITL's of pulsed power accelerators used to produce intense particle beams, Z's disk, transmission line (downstream of the current addition) is in a 100-1200-Tesla regime; so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code [2], [3], [17] MACH2 we have been investigating the conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. The three purposes of this work are 1) to quantify power flow losses owing to ultrahigh magnetic fields, 2) to model the response of VISAR [4], [18], [19] diagnostic samples in various configurations on Z, and 3) to incorporate the most appropriate equation of state and conductivity models into our magnetohydrodynamics (MHD) computations. Certain features are strongly dependent on the details of the conductivity model. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. NumerEx Inc, Albuquerque, NM 87106 USA. Univ New Mexico, Albuquerque, NM 87106 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Rosenthal, SE (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 21 TC 12 Z9 12 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1427 EP 1433 DI 10.1109/27.901209 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000022 ER PT J AU Cash, MA Cornette, JB Parkinson, ER Jamison, KA Fowler, CM Goettee, JD AF Cash, MA Cornette, JB Parkinson, ER Jamison, KA Fowler, CM Goettee, JD TI Benchmarking of a flux compression generator code SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE design; explosive; FCG; flux compression; generator; modeling; pulsed-power; simulation AB Science Applications International Corporation and the Air Force Research Laboratory are continuing development of a graphical design/simulation code for explosive flux compression generators (FCGs). "FCGSCA" is written in FORTRAN and Visual Basic and targets the Windows O/S (Microsoft, Chicago, IL). Basic physics principles and well-known circuit analysis techniques simulate generator-to-load performance; furthermore, FCGSCA incorporates an armature/stator inductance model, a "flux-loss'' model, and a fairly detailed treatment of the stator winding resistance. FCGSCA includes a capability for modeling transformer coupling and fuze snitching as part of various load configurations; additionally, the user can view overlays of time-history plots from one- or two-parameter variation studies. With reasonable costs in fidelity:, this approximation permits quick system-level simulations that expedite FCG design and development, Herein, we primarily explain the ease-of-use of the FCGSCA interface and report on some benchmarking against the "Ranchito" generator that has been designed and tested by Los blames National Laboratory (LANL). C1 USAF, Res Lab, Eglin AFB, FL 32542 USA. USAF, Res Lab, Directed Energy Directorate, Kirtland AFB, NM 87117 USA. Sci Applicat Int Corp, Ft Walton Beach, FL 32549 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Cash, MA (reprint author), USAF, Res Lab, Eglin AFB, FL 32542 USA. NR 3 TC 1 Z9 1 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1434 EP 1439 DI 10.1109/27.901210 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000023 ER PT J AU Brubaker, MA Yakymyshyn, CP AF Brubaker, MA Yakymyshyn, CP TI An electro-optic voltage sensor for electron beam position and current monitoring SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE accelerator; diagnostic; electron beam; electrooptic; Pockels cell AB The current and position of high-energy electron beams are traditionally monitored using B-dot loops and resistive wall monitors. Such techniques are well demonstrated for relatively short pulses in the 100 ns time regime. The second axis of the dual axis radiographic hydro test (DARHT) facility currently under construction at Los Alamos National Laboratory requires a substantially longer pulse exceeding 2 mus in duration, This application poses various difficulties for conventional sensors and has driven the development of an electro-optic sensor for electron beam monitoring. Such sensors offer complete galvanic isolation and do not require time integration or droop correction, The design of a prototype electro-optic sensor is discussed and calibration data is presented along with preliminary beam line measurements. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Montana State Univ, Dept Elect Engn, Bozeman, MT 59717 USA. RP Brubaker, MA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 9 TC 1 Z9 1 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1440 EP 1444 DI 10.1109/27.901211 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000024 ER PT J AU Savage, ME AF Savage, ME TI Final results from the high-current, high-action closing switch test program at Sandia National Laboratories SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE capacitor banks; spark gaps; snitches; thyristors; vacuum switches AB We tested a variety of high-current closing switches for lifetime and reliability on a dedicated 2-MJ, 500-kA capacitor bank facility at Sandia National Laboratories, Interest was in a snitch capable of one shot every few minutes, switching a critically damped, de-charged 6.7-mF bank at 24 kV: with a peak current of ol er 500 kA. The desired lifetime is 24 000 shots. Typical of high-energy systems, particularly multimodule systems, the primary parameters of interest related to the switch are 1) reliability, meaning absence of both pre-fires and no-fires; 2) total switch lifetime or number of shots between maintenance; 3) cost, Cost was given lower priority at the evaluation stage because there are uncertainties in estimating higher-quantity prices of these devices, most of which have been supplied before in only small quantities. Cost has more importance in choosing between viable candidates after testing. The categories of switches tested are vacuum discharge, high-pressure discharge, and solid-state. Each group varies in terms of triggering ease, ease-of-maintenance, and tolerance to faults such as excess current and current reversal. We tested at least two variations of each technology group. The total number of shots on the switch test facility is about 50 000, This paper will present the results from the snitch testing. The observed lifetime of different snitches varied greatly: the shortest life was one shot; one device was still operating after 6000 shots. On several switches, we measured the voltage drop during conduction and calculated energy dissipated in the switch; we will show these data also. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Savage, ME (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 14 TC 25 Z9 41 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1451 EP 1455 DI 10.1109/27.901213 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000026 ER PT J AU Dick, AR MacGregor, SJ Buttram, MT Pate, RC Rinehart, LF Prestwich, KR AF Dick, AR MacGregor, SJ Buttram, MT Pate, RC Rinehart, LF Prestwich, KR TI Breakdown phenomena in ultra-fast plasma closing switches SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE dielectric breakdown; gas discharges; plasma closing switches; transmission lines; UWB radar AB An experimental investigation into the rate of voltage collapse in plasma closing switches has been undertaken, A transmission line test switch, incorporating a radial/conical topology to minimize wave reflections, has been used for this investigation. The results described in this paper were obtained from experiments using hydrogen, helium, nitrogen, and SF6, The results show that there is a distinct change in breakdown behavior as the pressure increases. At the lowest tested pressures, there is a rapid voltage collapse phase. This phase reduces at intermediate pressures before recovering at higher pressures. This transition from low-pressure behavior to high-pressure behavior occurred in all the tested gases, although the transition pressure values were dependent on the gas type. C1 Univ Strathclyde, Dept Elect & Elect Engn, Glasgow G1 1XW, Lanark, Scotland. Sandia Natl Labs, Albuquerque, NM 87185 USA. Kenneth R Prestwich Consulting, Albuquerque, NM 87112 USA. RP Dick, AR (reprint author), Univ Strathclyde, Dept Elect & Elect Engn, Glasgow G1 1XW, Lanark, Scotland. NR 5 TC 10 Z9 12 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1456 EP 1462 DI 10.1109/27.901214 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000027 ER PT J AU Kambour, K Kang, S Myles, CW Hjalmarson, HP AF Kambour, K Kang, S Myles, CW Hjalmarson, HP TI Steady-state properties of lock-on current filaments in GaAs SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE collective impact ionization; lock-on; photoconductive semiconductor switches (PCSS) AB Collective impact ionization has been used to explain lock-on in semi-insulatiug GaAs under high-voltage bias. We have used this theory to study some of the steady-state properties of lock-on current filaments. In steady state, the heat gained from the field is exactly compensated by the cooling due to phonon scattering. In the simplest approximation, the carrier distribution approaches a quasi-equilibrium Maxwell-Boltzmann distribution, In this report, ne examine the validity of this approximation. We find that this approximation leads to a filament carrier density that is much lower than the high density needed to achieve a quasi-equilibrium distribution, Further work on this subject is in progress. C1 Texas Tech Univ, Dept Phys, Lubbock, TX 79409 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kambour, K (reprint author), Texas Tech Univ, Dept Phys, Lubbock, TX 79409 USA. NR 13 TC 11 Z9 15 U1 1 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1497 EP 1499 DI 10.1109/27.901221 PG 3 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000034 ER PT J AU Mar, A Loubriel, GM Zutavern, FJ O'Malley, MW Helgeson, WD Brown, DJ Hjalmarson, HP Baca, AG Thornton, RL Donaldson, RD AF Mar, A Loubriel, GM Zutavern, FJ O'Malley, MW Helgeson, WD Brown, DJ Hjalmarson, HP Baca, AG Thornton, RL Donaldson, RD TI Doped contacts for high-longevity optically activated, high-gain GaAs photoconductive semiconductor switches SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE diffusion; epitaxial growth; GaAs; lifetime; protoconductive switch AB The longevity of high-gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses. This was achieved by improving the ohmic contacts through the incorporation of a doped layer that is very effective in the suppression of filament formation, alleviating current crowding. Damage-free operation is now possible at much higher current levels than before. The inherent damage-free curl ent capacity of the bulk GaAs depends on the thickness of the doped layers and is at least 100 A for a dopant diffusion depth of 4 mum. This current could be increased by employing multiple switches connected in parallel, Thc contact metal has a different damage mechanism, and the threshold for damage (similar to 40-80 A) is not further improved beyond a dopant diffusion depth of about 2 mum. In a diffusion-doped contact sn itch, the switching performance is not degraded at the onset of contact metal erosion, unlike a switch with conventional contacts. For fireset applications operating at 1-kV/1-kA levels and higher, doped contacts have not yet resulted in improved longevity, We employ multifilament operation and InPb solder/Au ribbon wirebonding to demonstrate >100-shot lifetime at 1-kV/1-kA. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Xerox Corp, Palo Alto Res Ctr, Palo Alto, CA 94304 USA. RP Mar, A (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 5 TC 23 Z9 27 U1 2 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1507 EP 1511 DI 10.1109/27.901223 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000036 ER PT J AU Savage, ME Seidel, DB Mendel, CW AF Savage, ME Seidel, DB Mendel, CW TI Design of a command-triggered plasma opening switch for terawatt applications SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE inductive energy storage; magnetic insulation; modeling; plasma applications; pulse compression methods AB Inductive energy storage systems can have high-energy density, leading to smaller, less-expensive systems. The crucial element of an inductive energy storage system is the opening switch. This sn;itch must conduct current while energy is stored in an inductor, then open quickly to transfer this energy to a lend, Plasma can perform this function, The plasma opening switch (POS) has been studied for more than two decades. Though advances have been made, success with the conventional plasma opening snitch has been limited, The plasma opening snitch concept described here has the potential to increase the power achieved with inductive energy storage pulsed-power systems. This system is also command-triggered. Major improvements in performance and command-triggering both require control of the plasma conductor, This paper shows the design of a system that uses magnetic fields to control the plasma, An externally applied magnetic field clears plasma from the transmission line, For maximum power, efficiency, and accurate pulse shaping, the plasma must be cleared from most of the transmission line conductor spacing. The goal of the system described here is to clear more than 60% of the gap. This is much more than present performance levels, This paper discusses the operation of plasma opening sn itches, and the ways this snitch design overcomes some of the limitations, Because of the importance of magnetic field penetration into the plasma, a model for field penetration is presented, The design of a terawatt-level system is shown, and the mechanism to reduce the trigger power is described. Particle-in-cell simulations of the triggered opening are shown. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Savage, ME (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 10 TC 6 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1533 EP 1539 DI 10.1109/27.901228 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000041 ER PT J AU Reinovsky, RE AF Reinovsky, RE TI Pulsed power experiments in hydrodynamics and material properties SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE capacitor banks; high current; hydrodynamics; pulsed power applications AB In the last five years, a new application of high-performance pulsed power techniques within the Stockpile Stewardship Program has joined the traditional family of radiation source applications. This new application uses low-impedance, high-current drivers to produce high-energy density environments in materials for the study of material properties, instabilities, and hydrodynamics in complex geometries. The principle tool for producing high-energy density environments is the high-precision, magnetically imploded, near-solid density liner. The most attractive pulsed power system for driving such experiments is an ultrahigh current, low-impedance, microsecond rise-time source that is economical both to build and to operate. In this paper we will review basic scaling arguments that set the scope of high-energy density environments made available by pulsed power-driven liners. We provide a summary of some investigations into the physics limiting the performance of near-solid metal liners under magnetic drive. We mill present a fell examples of hydrodynamic experiments enabled by liners drive and note some demonstration experiments already performed with inter im systems. Finally, me will overview the pulsed power techniques under development at Los Alamos for high-energy density experiments. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Reinovsky, RE (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1563 EP 1570 DI 10.1109/27.901234 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000047 ER PT J AU Smith, ID Bailey, VL Fockler, J Gustwiller, JS Johnson, DL Maenchen, JE Droemer, DW AF Smith, ID Bailey, VL Fockler, J Gustwiller, JS Johnson, DL Maenchen, JE Droemer, DW TI Design of a radiographic integrated test stand (RITS) based on a voltage adder, to drive a diode immersed in a high magnetic field SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Recent experiments [1] have adapted existing magnetically insulated induction voltage adders.(Sabre, Hermes III) to drive a 10-MV diode immersed in magnetic fields as high as 50 T. In such a diode, an electron beam of tens of kiloamperes can be confined by the magnetic field to a diameter of about 1 mm, and when it strikes a high-Z anode, it can create a bremsstrahlung X-ray source intense enough to radiograph massive objects with high resolution. The radiographic integrated test stand (RITS) is an adder system designed specially to drive such diodes, and it will be used to develop and exploit them. As in other adder-based pulsers, such as Sabre, Hermes III, and Kalif-Helia, the induction cells have amorphous-iron cores, and the pulse-forming system consists of water dielectric pulselines and self-closing water snitches that are pulse-charged from Marx-charged intermediate water capacitors through laser-triggered Rimfire snitches. An oil prepulse switch in series with each pulseline is designed to reduce cathode prepulse to less than +/-5 kV, and a means is provided to bias the cathode and avoid negative prepulse entirely. The RITS pulse-forming system consists of two modules. Each module has one Marx that charges two 3-MV intermediate stores, each of which charges three 7.8-Omega pulselines, making sis pulselines per module. The two modules in concert can supply 1.35-MV, 50-ns pulses to a 12-cell adder and thus drive a 16-MV diode with a single pulse. The 1.35-MV induction cells each have a single-point feed, from which a single, slotted azimuthal oil transmission line distributes energy uniformly around the cell. The modules can also be pulsed separately at different times, either to power two 8-MV adders that each drive one of two closely spaced cathodes immersed in a common magnetic field or to provide two separate pulses to a common six-cell adder and a single 8-MV diode; in these two-pulse modes, the spacing of the two 50-ns pulses may be chosen to be anything from a fe rv hundred nanoseconds upward. The use of only one pulseline per cell has been shown to increase the extent to which the cell voltages can vary with the timing of closure of the water sn itches. This and all other functions of RITS have been simulated in detail, and a conservative electrical design has been developed. This will be illustrated, along with the conceptual design of a pulse-sorting network that can couple two pulselines efficiently to one cell when the two RITS modules drive a common adder in two-pulse mode. C1 Pulse Sci Inc, San Leandro, CA 94577 USA. JFC, Castro Valley, CA 94546 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Bechtel, N Las Vegas, NV 89030 USA. RP Smith, ID (reprint author), Pulse Sci Inc, San Leandro, CA 94577 USA. NR 10 TC 39 Z9 42 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 2000 VL 28 IS 5 BP 1653 EP 1659 DI 10.1109/27.901250 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 402WK UT WOS:000167011000063 ER PT J AU Brubaker, MA Nelson, JK AF Brubaker, MA Nelson, JK TI A parametric study of streaming electrification in a full-scale core-form transformer winding using a network-based model SO IEEE TRANSACTIONS ON POWER DELIVERY LA English DT Article DE charge density; core-form transformer; oil flow; static electrification; static potential; winding ducts AB Streaming electrification remains a problem for large power transformers which require forced-oil cooling. Oil flowing against cellulose insulation surfaces results in the separation of charges from the electrical double layer at the interface. This process can generate hazardous static potentials and volume charge densities in the transformer dielectric system, While streaming electrification has been studied in great detail using small-scale laboratory models, extension of these results to full-scale transformers is rather difficult. This issue has been addressed through the development of a network-based analytical approach which is calibrated against empirical data at the elemental duct level. The model has been utilized to perform a parametric study of streaming electrification in the full-scale high-voltage winding of a core-form transformer. Volume charge densities exiting from each duct in the structure and the local surface potentials are predicted as a function of influent charge, oil volume flow rate, temperature and applied voltage. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Rensselaer Polytech Inst, Troy, NY 12180 USA. RP Brubaker, MA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 4 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8977 J9 IEEE T POWER DELIVER JI IEEE Trans. Power Deliv. PD OCT PY 2000 VL 15 IS 4 BP 1188 EP 1192 DI 10.1109/61.891501 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA 384NL UT WOS:000165951700013 ER PT J AU Davis, DP Raffen, R Dul, JL Vogen, SM Williamson, EK Stevens, FJ Argon, Y AF Davis, DP Raffen, R Dul, JL Vogen, SM Williamson, EK Stevens, FJ Argon, Y TI Inhibition of amyloid fiber assembly by both BiP and its target peptide SO IMMUNITY LA English DT Article ID AMINO-ACID SUBSTITUTION; IG LIGHT-CHAINS; ENDOPLASMIC-RETICULUM; FIBRIL FORMATION; MOLECULAR CHAPERONES; DOMAIN INTERACTIONS; DEPOSITION DISEASE; BINDING-PROTEIN; VARIABLE DOMAIN; ATPASE ACTIVITY AB Immunoglobulin light chain (LC) normally is a soluble, secreted protein, but some LC assemble into ordered fibrils whose deposition in tissues results in amyloidosis and organ failure. Here we reconstitute fibril formation in vitro and show that preformed fibrils can nucleate polymerization of soluble LC. This prion-like behavior has important physiological implications, since somatic mutations generate multiple related LC sequences. Furthermore, we demonstrate that fibril formation in vitro and aggregation of whole LC within cells are inhibited by BiP and by a synthetic peptide that is identical to a major LC binding site for Sip. We propose that LC form fibrils via an interprotein loop swap and that the underlying conformational change should be amenable to drug therapy. C1 Univ Chicago, Dept Pathol, Chicago, IL 60637 USA. Univ Chicago, Comm Immunol, Chicago, IL 60637 USA. Univ Chicago, Dept Mol Genet & Cell Biol, Chicago, IL 60637 USA. Argonne Natl Lab, Biosci Div, Argonne, IL 60439 USA. RP Argon, Y (reprint author), Univ Chicago, Dept Pathol, 5841 S Maryland Ave, Chicago, IL 60637 USA. NR 49 TC 26 Z9 27 U1 0 U2 4 PU CELL PRESS PI CAMBRIDGE PA 1050 MASSACHUSETTES AVE, CIRCULATION DEPT, CAMBRIDGE, MA 02138 USA SN 1074-7613 J9 IMMUNITY JI Immunity PD OCT PY 2000 VL 13 IS 4 BP 433 EP 442 DI 10.1016/S1074-7613(00)00043-1 PG 10 WC Immunology SC Immunology GA 367UD UT WOS:000090079100003 ER PT J AU Bond, AH Dietz, ML Chiarizia, R AF Bond, AH Dietz, ML Chiarizia, R TI Incorporating size selectivity into synergistic solvent extraction: A review of crown ether-containing systems SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Review ID ATOMIC-ABSORPTION SPECTROMETRY; DIDODECYLNAPHTHALENE SULFONIC-ACID; ACTIVE WASTE SOLUTIONS; ALKALINE-EARTH METALS; ION-PAIR EXTRACTION; NITROBENZENE SOLUTION; TRIVALENT LANTHANIDES; MOLECULAR-STRUCTURE; 18-CROWN-6 ETHER; THENOYLTRIFLUOROACETONE COMPLEX AB This paper provides a comprehensive review of synergistic solvent extraction using crown ethers with a focus on the role of both extractants in facilitating cation-specific separations. An introduction to the various equilibria affecting synergistic extraction using crown ethers is followed by a review of the work published in this field during the 1972-1999 time period. The influence of various solvent extraction parameters on the potential for cation-selective synergism is critically examined. Those synergistic extractant combinations showing cation selectivity are highlighted, as are the fundamental investigations that are the foundation of the current understanding of synergistic solvent extraction using crown ethers. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Bond, AH (reprint author), PG Res Fdn Inc, 8205 S Cass Ave,Suite 111, Darien, IL 60561 USA. NR 186 TC 85 Z9 86 U1 3 U2 29 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD OCT PY 2000 VL 39 IS 10 BP 3442 EP 3464 DI 10.1021/ie000356j PG 23 WC Engineering, Chemical SC Engineering GA 361QE UT WOS:000089733100007 ER PT J AU Satake, S Kunugi, T Shehata, AM McEligot, DM AF Satake, S Kunugi, T Shehata, AM McEligot, DM TI Direct numerical simulation for laminarization of turbulent forced gas flows in circular tubes with strong heating SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Article; Proceedings Paper CT 1st International Symposium on Turbulence and Shear Flow Phenomena (TSFP-1) CY SEP 12-15, 1999 CL SANTA BARBARA, CALIFORNIA DE laminarization; heat transfer; turbulent flow; tube; gas property variation ID EQUATIONS AB The direct numerical simulation (DNS) of turbulent transport for a gas with variable properties has been conducted to grasp and understand the laminarization phenomena caused by strong heating. In this study, the inlet Reynolds number based on a bulk velocity and pipe diameter was taken as Re= 4300 as in the experiments by Shehata and McEligot (1998), The measured wall temperature distribution was applied as a thermal boundary condition. The number of computational nodes used in the heated region was 768 x 64 x 128 in the z-, r- and phi-directions, respectively. Turbulent quantities, such as the mean flow, temperature fluctuations, turbulent stresses and the turbulent statistics, were obtained via DNS. Predicted mean velocity and temperature distributions and integral parameters agreed well with the experiments. The Reynolds shear stress, indicating turbulent transport of momentum, decreases along the streamwise direction. The cause of this reduction can be considered to be that the fluid behavior changes drastically in the near wall region due to strong heating which induces significant variations of the gas properties and, in turn. acceleration and buoyancy effects. In a visualization of the results, one sees that the vortical structures are primarily suppressed within the first section of the heated region (z/D = 0-5) and are not regenerated further downstream. (C) 2000 Begell House Inc. Published by Elsevier Science Inc. All rights reserved. C1 Toyama Univ, Dept Mech Syst Engn, Toyama 9308555, Japan. Kyoto Univ, Dept Nucl Engn, Kyoto 6068501, Japan. Xerox Corp, Webster, NY 14580 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Univ Arizona, Tucson, AZ 85721 USA. RP Satake, S (reprint author), Toyama Univ, Dept Mech Syst Engn, Toyama 9308555, Japan. NR 24 TC 22 Z9 22 U1 1 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD OCT PY 2000 VL 21 IS 5 BP 526 EP 534 DI 10.1016/S0142-727X(00)00041-2 PG 9 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 356RK UT WOS:000089456400009 ER PT J AU Dreeben, TD Kerstein, AR AF Dreeben, TD Kerstein, AR TI Simulation of vertical slot convection using 'one-dimensional turbulence' SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID NATURAL-CONVECTION; FLOW AB One-dimensional turbulence (ODT) is used to model and simulate the buoyant turbulent flow in a vertical slot. ODT reproduces available Direct Numerical Simulation results on the Rayleigh number dependence of wall heat transfer and of other flow properties of interest. Extended ranges of Rayleigh and Prandtl numbers are investigated with ODT to explore the broader behavior of the flow, focusing on its connection to classical scaling arguments. Published by Elsevier Science Ltd. C1 Osram Sylvania, Beverly, MA 01915 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. RP Dreeben, TD (reprint author), Osram Sylvania, 71 Cherry Hill Dr, Beverly, MA 01915 USA. NR 14 TC 18 Z9 19 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD OCT PY 2000 VL 43 IS 20 BP 3823 EP 3834 DI 10.1016/S0017-9310(00)00012-0 PG 12 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 346BC UT WOS:000088849500007 ER PT J AU Hijazi, MM Thompson, EW Tang, C Coopman, P Torri, JA Yang, DJ Mueller, SC Lupu, R AF Hijazi, MM Thompson, EW Tang, C Coopman, P Torri, JA Yang, DJ Mueller, SC Lupu, R TI Heregulin regulates the actin cytoskeleton and promotes invasive properties in breast cancer cell lines SO INTERNATIONAL JOURNAL OF ONCOLOGY LA English DT Article DE heregulin; erbB(2); growth; invasion; cell motility; actin cytoskeleton ID EPIDERMAL GROWTH-FACTOR; NEU DIFFERENTIATION FACTOR; MAMMARY EPITHELIAL-CELLS; ESTROGEN-RECEPTOR; PHOSPHATIDYLINOSITOL 3-KINASE; TYROSINE PHOSPHORYLATION; BASEMENT-MEMBRANE; ONCOGENE PRODUCT; EGF RECEPTOR; TUMOR CELLS AB The metastatic process requires changes in tumor cell adhesion properties, cell motility and remodeling of the extracellular matrix. The erbB(2) proto-oncogene is overexpressed in approximately 30% of breast cancers and is a major prognostic parameter when present, in invasive disease. A ligand for the erbB(2) receptor has not yet been identified but it can be activated by heterodimerization with heregulin (HRG)-stimulated erbB(3) and erbB(4) receptors. The HRGs are a family of polypeptide growth factors that have been shown to play a role in embryogenesis, tumor formation, growth and differentiation of breast cancer cells. The erbB(3) and erbB(4) receptors are involved in transregulation of erbB(2) signaling. The work presented here suggests biological roles for HRG including regulation of the actin cytoskeleton and induction of motility and invasion in breast cancer cells. HRG-expressing breast cancer cell lines are characterized by low erbB receptor levels and a high invasive and metastatic index, while those which overexpress erbB(2) demonstrate minimal invasive potential in vitro and are non-tumorigenic in vivo. Treatment of the highly tumorigenic and metastatic HRG-expressing breast cancer cell line MDA-MB-231 with an HRG-neutralizing antibody significantly inhibited proliferation in culture and motility in the Boyden chamber assay. Addition of exogenous HRG to non-invasive erbB(2) overexpressing cells (SKBr-3) at low concentrations induced formation of pseudopodia, enhanced phagocytic activity and increased chemomigration and invasion in the Boyden chamber assay. The specificity of the chemomigration response to HRG is demonstrated by inhibition with the anti-HRG neutralizing antibody. These results suggest that either HRG can act as an autocrine or paracrine ligand to promote the invasive behavior of breast cancer cells in vitro or thus may enhance the metastatic process in vivo. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Georgetown Univ, Med Ctr, Vincent T Lombardi Canc Res Ctr, Washington, DC 20007 USA. RP Lupu, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Thompson, Erik/A-1425-2009 OI Thompson, Erik/0000-0002-9723-4924 FU NIDDK NIH HHS [R01-DK49049] NR 66 TC 56 Z9 57 U1 0 U2 4 PU PROFESSOR D A SPANDIDOS PI ATHENS PA 1, S MERKOURI ST, EDITORIAL OFFICE,, ATHENS 116 35, GREECE SN 1019-6439 J9 INT J ONCOL JI Int. J. Oncol. PD OCT PY 2000 VL 17 IS 4 BP 629 EP 641 PG 13 WC Oncology SC Oncology GA 356TY UT WOS:000089460000001 PM 10995872 ER PT J AU Fuhrer, J Gaboriault, E Tang, F Xu, XP AF Fuhrer, J Gaboriault, E Tang, F Xu, XP TI AXEL Madsen/CPMT scholarship reports SO INTERNATIONAL JOURNAL OF POWDER METALLURGY LA English DT Editorial Material C1 Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. Worcester Polytech Inst, Powder Met Res Ctr, Worcester, MA USA. Iowa State Univ, Ames Lab, Ames, IA USA. Penn State Univ, Ctr Innovat Sintered Prod, University Pk, PA 16802 USA. RP Fuhrer, J (reprint author), Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER POWDER METALLURGY INST PI PRINCETON PA 105 COLLEGE ROAD EAST, PRINCETON, NJ 08540 USA SN 0888-7462 J9 INT J POWDER METALL JI Int. J. Powder Metall. PD OCT PY 2000 VL 36 IS 7 BP 41 EP 45 PG 5 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 368PA UT WOS:000090125400014 ER PT J AU Newman, GA Hoversten, GM AF Newman, GA Hoversten, GM TI Solution strategies for two- and three-dimensional electromagnetic inverse problems SO INVERSE PROBLEMS LA English DT Article ID SMOOTH; MODELS; FIELDS AB We analyse a variety of solution strategies for nonlinear two-dimensional (2D) and three-dimensional (3D) electromagnetic (EM) inverse problems. To impose a realistic parameterization on the problem, the finite-difference equations arising from Maxwell equations are employed in the forward problem. Krylov subspace methods are then used to solve the resulting linear systems. Because of the efficiencies of the Krylov methods, they are used as the computational kernel for solving 2D and 3D inverse problems, where multiple solutions of the forward problem are required. We derive relations for computing the full Hessian matrix and functional gradient that are needed For computing the model update. via the Newton iteration. Different strategies are then discussed for economically carrying out the Newton iteration for 2D and 3D problems, including the incorporation of constraints necessary to stabilize the inversion process. Two case histories utilizing EM inversion are presented. These include inversion of cross-well data for monitoring electrical conductivity changes arising From an enhanced oil recovery project and the usefulness of cross-well EM methods to characterize the transport pathways for contaminants in the subsurface. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94729 USA. RP Newman, GA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Newman, Gregory/G-2813-2015 NR 35 TC 43 Z9 46 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0266-5611 J9 INVERSE PROBL JI Inverse Probl. PD OCT PY 2000 VL 16 IS 5 BP 1357 EP 1375 DI 10.1088/0266-5611/16/5/314 PG 19 WC Mathematics, Applied; Physics, Mathematical SC Mathematics; Physics GA 372NZ UT WOS:000165241000015 ER PT J AU Wilkes, KE Liaw, PK AF Wilkes, KE Liaw, PK TI The fatigue behavior of shape-memory alloys SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID CYCLIC DEFORMATION; NI-TI; POLYCRYSTALLINE; TEMPERATURE; MARTENSITE; PHASE; MS AB Shape-memory alloys have two unique properties: the shape-memory effect (ability of a material to be deformed at a low temperature and then revert to its prior shape upon heating) and superelasticity (the ability of a material to experience large recoverable strains when deformed). Many applications that take advantage of these properties require cyclic deformation, making fatigue behavior an important consideration. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN USA. RP Liaw, PK (reprint author), Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. NR 41 TC 15 Z9 16 U1 1 U2 7 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD OCT PY 2000 VL 52 IS 10 BP 45 EP 51 DI 10.1007/s11837-000-0083-3 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 364MR UT WOS:000089896600008 ER PT J AU Porter, GA Liaw, PK Tiegs, TN Wu, KH AF Porter, GA Liaw, PK Tiegs, TN Wu, KH TI Ni-TiSMA-reinforced Al composites SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article ID MATRIX COMPOSITE; ALUMINUM AB A shape-memory alloy, nickel-titanium, has been distributed throughout an aluminum matrix, using powder-metallurgy processing, in the hope of using the shape-memory effect to achieve strengthening and improve the fatigue resistance, as compared to the aluminum matrix. The shape-memory effect was activated by cold rolling the samples at -30 degrees C . Upon reheating to the austenite phase, the Ni-Ti was expected to return to its original shape while embedded in the aluminum matrix. It is thought that this action created residual, internal stresses around each particle, which strengthened the material. The yield and ultimate strengths, and the fatigue lives of the Ni-Ti reinforced aluminum composites, have been improved considerably, as compared to the unreinforced material. The cross-sectional microstructures of the composites, as well as the modes of crack growth, have been examined with a scanning electron microscope (SEM) to identify fatigue and fracture mechanisms. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN USA. Florida Int Univ, Dept Mech Engn, Miami, FL 33199 USA. RP Liaw, PK (reprint author), Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. OI Porter, Glen/0000-0001-5598-4041 NR 20 TC 20 Z9 21 U1 1 U2 5 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD OCT PY 2000 VL 52 IS 10 BP 52 EP 56 DI 10.1007/s11837-000-0084-2 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 364MR UT WOS:000089896600009 ER PT J AU Wolfenden McGuff, MS Vaidya, RU AF Wolfenden McGuff, MS Vaidya, RU TI The effects of thermal cycling on the dynamic elastic modulus and vibration damping of SiC/Ti-6Al-2Sn-4Zr-2Mo composites SO JOURNAL OF ADVANCED MATERIALS LA English DT Article AB The elastic properties of a titanium alloy, Ti-6Al-2Sn-4Zr-2Mo, and two SiC reinforced composites, SiC/Ti-6Al-2Sn-4Zr-2Mo, were studied. One of the composite specimens had the fibers oriented at 0 degrees (lengthwise) and the other contained fibers at 90 degrees. The density of the three specimens was measured using Archimedes' method. The Piezoelectric Ultrasonic Oscillator Technique (PUCOT) technique was utilized to determine the Young's modulus and vibration damping as a function of strain amplitude. The specimens were thermally cycled between room temperature and 550 degrees C. The modulus and vibration damping of the specimens were measured after every five cycles. The specimen with the cross fibers (90 degrees) showed the largest change in stiffness. This is probably a result of the large number of fiber ends exposed to ail: The damping increased in the two composite specimens. Every specimen showed signs of break-au ay damping as the strain amplitude Mas increased. This information was then used to estimate the dislocation density as well as the minor pinning length between impurity atoms. C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Wolfenden (reprint author), Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 1070-9789 J9 J ADV MATER JI J. Adv. Mater. PD OCT PY 2000 VL 32 IS 4 BP 60 EP 65 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 361DJ UT WOS:000089707100009 ER PT J AU Nakao, S Najita, J Karasaki, K AF Nakao, S Najita, J Karasaki, K TI Hydraulic well testing inversion for modeling fluid flow in fractured rocks using simulated annealing: a case study at Raymond field site, California SO JOURNAL OF APPLIED GEOPHYSICS LA English DT Article DE hydraulic well test; inversion; fluid flow model; fractured rocks; simulated annealing ID SYSTEMS AB Cluster variable aperture (CVA) simulated annealing (SA) is an inversion technique to construct fluid flow models in fractured rocks based on the transient pressure data from hydraulic tests. A two-dimensional fracture network; system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes element apertures for a cluster of fracture elements in order to improve the match to observed pressure transients. This inversion technique has been applied to hydraulic data collected at the Raymond field site, CA to examine the spatial characteristics of the flow properties in a fractured rock mass, Two major conductive zones have been detected by various geophysical logs, geophysical imaging techniques and hydraulic tests; one occurring near a depth of 30 m and the other near a depth of 60 m. Our inversion results show that the practical range of spatial correlation for transmissivity distribution is estimated to be: approximately 5 m in the upper zone and less than 2.5 In in the lower zones. From the televiewer and other fracture imaging logs it was surmised that the lower conductive zone is associated with an anomalous single open fracture as compared to the upper zone, which is an extensive Fracture zone, This would explain the difference in the estimated practical range of the spatial correlation for transmissivity. (C) 2000 Elsevier Science B,V. All rights reserved. C1 Geol Survey Japan, Tsukuba, Ibaraki 3058567, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Nakao, S (reprint author), Geol Survey Japan, 1-1-3 Higashi, Tsukuba, Ibaraki 3058567, Japan. EM nakao@gsj.go.jp; jsnajita@lbl.gov; kkarasaki@lbl.gov NR 29 TC 10 Z9 10 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0926-9851 J9 J APPL GEOPHYS JI J. Appl. Geophys. PD OCT PY 2000 VL 45 IS 3 BP 203 EP 223 DI 10.1016/S0926-9851(00)00029-X PG 21 WC Geosciences, Multidisciplinary; Mining & Mineral Processing SC Geology; Mining & Mineral Processing GA 371MU UT WOS:000165183400005 ER PT J AU Myers, SM Seibt, M Schroter, W AF Myers, SM Seibt, M Schroter, W TI Mechanisms of transition-metal gettering in silicon SO JOURNAL OF APPLIED PHYSICS LA English DT Review ID CZOCHRALSKI-GROWN SILICON; IMPLANTATION-INDUCED CAVITIES; LEVEL TRANSIENT-SPECTROSCOPY; BULK STACKING-FAULTS; BORON-DOPED SILICON; ION-IMPLANTATION; PHOSPHORUS-DIFFUSION; CHARGE-STATE; SOLAR-CELLS; POLYCRYSTALLINE SILICON AB The atomic process, kinetics, and equilibrium thermodynamics underlying the gettering of transition-metal impurities in Si are reviewed. Methods for mathematical modeling of gettering are discussed and illustrated. Needs for further research are considered. (C) 2000 American Institute of Physics. [S0021-8979(00)04719-8]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Gottingen, Inst Phys 4, D-37073 Gottingen, Germany. RP Myers, SM (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. OI Seibt, Michael/0000-0002-9908-400X NR 150 TC 180 Z9 190 U1 6 U2 30 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 OCT 1 PY 2000 VL 88 IS 7 BP 3795 EP 3819 AR PII [S0021-8979(00)04719-8] DI 10.1063/1.1289273 PG 25 WC Physics, Applied SC Physics GA 355DY UT WOS:000089371600001 ER PT J AU Inal, MY Alam, M Peascoe, RA Watkins, TR AF Inal, MY Alam, M Peascoe, RA Watkins, TR TI Residual stress in deuterium implanted nominal copper coatings SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THIN-FILMS; ION-IMPLANTATION; INTERNAL-STRESS; TEXTURE; IRRADIATION; PERMEATION; RETENTION; TRITIUM AB The effects of deuterium (D) implantation on the residual stresses in Cu and CuAl2 phases present in nominal Cu coatings (containing Al) deposited on Al-alloy (Al-6061) substrates were measured using an x-ray diffraction technique. The coatings were deposited by radio frequency magnetron sputtering of a pure Cu target under identical conditions and Al was incorporated in the coatings during growth by diffusion from the substrate. Deuterium was implanted in the coatings at energies of 40 or 40+120 keV with fluences of 1 x 10(21), 2 x 10(21), or 3 x 10(21) D+/m(2). Pole figures of the Cu phase in the coatings prior to and after implantation indicated no effect of implantation on the fibrous texture. Triaxial stress analysis indicated the surface normal stress component to be negligible in Cu and slightly tensile in CuAl2 under all conditions. Furthermore, under all conditions, the in-plane residual stresses in both phases were found to be compressive and nearly isotropic. The magnitude of the isotropic compressive stress was always higher in CuAl2 as compared to Cu. The compressive residual stresses in the Cu phase changed only mildly with increasing coating weight, ion energy, and fluence. However, in the CuAl2 phase the compressive residual stresses changed markedly with increasing ion energy (initial decrease followed by leveling off) and increasing ion fluence (initial decrease followed by an increase), but remained unaffected by increasing coating weight. (C) 2000 American Institute of Physics. [S0021-8979(00)07819-1]. C1 New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. Oak Ridge Natl Lab, High Temp Mat Lab, Oak Ridge, TN 37831 USA. RP Alam, M (reprint author), New Mexico Inst Min & Technol, Dept Mat & Met Engn, Socorro, NM 87801 USA. RI Watkins, Thomas/D-8750-2016 OI Watkins, Thomas/0000-0002-2646-1329 NR 27 TC 4 Z9 4 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 2000 VL 88 IS 7 BP 3919 EP 3925 AR PII [S0021-8979(00)07819-1] DI 10.1063/1.1289795 PG 7 WC Physics, Applied SC Physics GA 355DY UT WOS:000089371600016 ER PT J AU Guha, S Qadri, SB Musket, RG Wall, MA Shimizu-Iwayama, T AF Guha, S Qadri, SB Musket, RG Wall, MA Shimizu-Iwayama, T TI Characterization of Si nanocrystals grown by annealing SiO2 films with uniform concentrations of implanted Si SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID POROUS SILICON; OPTICAL-PROPERTIES; ION-IMPLANTATION; PARTICLE-SIZE; LUMINESCENCE AB We have performed physical and optical characterization of Si nanocrystals grown by ion implantation of Si+ ions at multiple energies with varying doses into thermally grown SiO2 films. The purpose of multiple implants was to achieve uniform composition of the added Si profile throughout the SiO2 film to produce Si particles with a narrow size distribution upon annealing at 1000 degrees C in a nitrogen atmosphere. The depth distribution of the composition and sizes of the Si particles in SiO2 films before and after the anneal were determined using Rutherford backscattering (RBS), forward recoil spectroscopy, small-angle x-ray diffraction (SXRD), and high-resolution transmission electron microscopy (HRTEM). From RBS we concluded that the amount of free silicon was reduced by annealing, presumably due to oxidation in the annealing process. The mean cluster sizes of the annealed samples were determined by SXRD. HRTEM was also employed to determine the average size of Si particles. Photoluminescence spectra (PL) from these samples were broad and the peak positions of the PL spectra were blue-shifted with decreasing cluster size. The line shapes of the PL spectra were calculated with a quantum confinement model assuming a log-normal size distribution of Si nanoparticles and (1/D)(1.25) dependence of the band gap energy as a function of particle size D. The band gap energy and the average particle size obtained from the calculated line shape spectra agree well with the quantum confinement model. (C) 2000 American Institute of Physics. [S0021-8979(00)04020-2]. C1 USN, Div Mat Sci & Technol, Res Lab, Washington, DC 20375 USA. Univ Calif Lawrence Livermore Natl Lab, Div Mat Sci & Technol, Livermore, CA 94550 USA. Aichi Univ Educ, Dept Mat Sci, Kariya, Aichi 4488542, Japan. RP Guha, S (reprint author), Nanosci Technol, Silver Spring, MD USA. NR 14 TC 53 Z9 53 U1 2 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 2000 VL 88 IS 7 BP 3954 EP 3961 DI 10.1063/1.1308096 PG 8 WC Physics, Applied SC Physics GA 355DY UT WOS:000089371600021 ER PT J AU Lu, CJ Wang, ZL Kwon, C Jia, QX AF Lu, CJ Wang, ZL Kwon, C Jia, QX TI Microstructure of epitaxial La0.7Ca0.3MnO3 thin films grown on LaAlO3 and SrTiO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID 3-DIMENSIONAL STRAIN STATES; LOW-FIELD MAGNETORESISTANCE; PULSED-LASER DEPOSITION; COLOSSAL MAGNETORESISTANCE; GIANT MAGNETORESISTANCE; DOMAIN-STRUCTURE; MAGNETIC-ANISOTROPY; DOUBLE-EXCHANGE; MAGNETOTRANSPORT; LA1-XSRXMNO3 AB Epitaxial La0.7Ca0.3MnO3 (LCMO) thin films of a thickness similar to 170 nm were grown on (001) LaAlO3 (LAO) and (001) SrTiO3 (STO) substrates by pulsed laser deposition. Transmission electron microscopy and associated techniques have been applied to investigate the microstructures introduced by lattice mismatch that are responsible for the observed differences in properties between these two films. Numerous secondary phase rods were observed in both films. For the LCMO/LAO film, Ca-deficient secondary-phase rods originated in the film after a thickness of about 25 nm and were found to be responsible for relieving in-plane compressive stress during the island growth. In the case of STO substrate, however, almost all of secondary-phase rods initiated at the film-substrate interface. The lattice mismatch between LCMO and STO is relaxed into regions of good coherent fit separated by such secondary phases, possibly resulting from interfacial reaction. The two types of substrates lead to the formation of two different crystallographic domain structures in the LCMO films. The film on LAO exhibits an almost pure [110] out-of-plane texture with 90 degrees domains in plane. In contrast, the film grown on STO consists of mixed domains of [001] and [110] orientations and is dominated by [001] texture. (C) 2000 American Institute of Physics. [S0021-8979(00)03620-3]. C1 Chinese Acad Sci, Ctr Condensed Matter, Beijing Lab Electron Microscopy, Beijing 100080, Peoples R China. Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China. Calif State Univ Long Beach, Dept Phys & Astron, Long Beach, CA 90840 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Hubei Univ, Dept Phys, Wuhan 430062, Peoples R China. Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. RP Lu, CJ (reprint author), Chinese Acad Sci, Ctr Condensed Matter, Beijing Lab Electron Microscopy, POB 2724, Beijing 100080, Peoples R China. RI Kwon, Chuhee/A-8687-2008; Wang, Zhong Lin/E-2176-2011; Jia, Q. X./C-5194-2008 OI Wang, Zhong Lin/0000-0002-5530-0380; NR 42 TC 79 Z9 81 U1 1 U2 16 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 OCT 1 PY 2000 VL 88 IS 7 BP 4032 EP 4043 DI 10.1063/1.1290741 PG 12 WC Physics, Applied SC Physics GA 355DY UT WOS:000089371600034 ER PT J AU Qiao, D Yu, LS Lau, SS Lin, JY Jiang, HX Haynes, TE AF Qiao, D Yu, LS Lau, SS Lin, JY Jiang, HX Haynes, TE TI A study of the Au/Ni ohmic contact on p-GaN SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; ELECTRICAL-PROPERTIES; THIN-FILMS; MECHANISM; HYDROGEN AB The formation mechanism of the ohmic Au/Ni/p-GaN contact has been investigated. We found that it is essential to (i) deposit a structure of Au and Ni in the proper deposition sequence, and (ii) anneal the bilayer structure in an oxygen containing ambient. Our findings indicated that oxygen assists the layer-reversal reactions of the metallized layers to form a structure of NiO/Au/p-GaN. The presence of oxygen during annealing appears to increase the conductivity of the p-GaN. It is further suggested that Ni removes or reduces the surface contamination of the GaN sample before or during layer reversal. In the final contact structure, an Au layer, which has a large work function, is in contact with the p-GaN substrate. The presence of Au in the entire contacting layer improves the conductivity of the contact. An ohmic formation mechanism based on our experimental results is proposed and discussed in this work. (C) 2000 American Institute of Physics. [S0021-8979(00)02621-9]. C1 Univ Calif San Diego, ECE Dept, La Jolla, CA 92093 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Qiao, D (reprint author), Univ Calif San Diego, ECE Dept, La Jolla, CA 92093 USA. EM dqiao@ucsd.edu RI Lin, Jingyu/A-7276-2011; Jiang, Hongxing/F-3635-2011; Haynes, Tony/P-8932-2015 OI Lin, Jingyu/0000-0003-1705-2635; Jiang, Hongxing/0000-0001-9892-4292; Haynes, Tony/0000-0003-2871-4745 NR 22 TC 64 Z9 71 U1 2 U2 22 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 2000 VL 88 IS 7 BP 4196 EP 4200 AR PII [S0021-8979(00)02621-9] DI 10.1063/1.1311809 PG 5 WC Physics, Applied SC Physics GA 355DY UT WOS:000089371600061 ER PT J AU Disselkamp, RS Carpenter, MA Cowin, JP AF Disselkamp, RS Carpenter, MA Cowin, JP TI A chamber investigation of nitric acid-soot aerosol chemistry at 298 k SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE soot aerosol; nitric acid ID BLACK CARBON SOOT; LOWER STRATOSPHERE; UPPER TROPOSPHERE; EMISSIONS; AIR AB Long-pathlength infrared absorption spectroscopy was used to investigate nitric acid-soot aerosol chemistry at 298 K and 0.5% relative humidity. Experiments were performed by introducing nitric acid vapor (P-HNO3 similar to 3 Pa, P-total similar to 40 kPa) into a teflon-coated chamber and initiating acquisition of infrared spectra at 3 minute time intervals. After 36 minutes of data collection, soot powder was rapidly expanded into nitric acid contained in the chamber to generate a soot-HNO3 aerosol. Infrared spectra collected before, and after, soot introduction to the chamber were used to characterize chamber wall reaction processes and soot aerosol chemistry, respectively. Three soot types were investigated (Degussa FW2, Cabot Monarch 1000, and crystalline graphite), each yielding similar chemistry. Upon soot introduction to the chamber both HNO3 uptake and NO2 production occurred, with the molar ratio of HNO3 uptake to NO2 production varying from 1.2 to 2.9 for the three soot types studied. Unreacted HNO3 was present at the conclusion of each of the aerosol experiments, indicating incomplete conversion of HNO3 into NO2. This observation suggested that 'active' sites at the soot surface responsible for the reduction of HNO3 are not regenerated (i.e., formed) in the reaction process. In essence, a titration occurred between these active sites and HNO3. The NO2 concentrations produced, the soot mass concentrations used, and the BET measured specific surface area of the powders allowed computation of the surface density of active sites of similar to 4.0 x 10(-18) m(2)/active site (describing all three powders studied). This is the first reported measurement of surface density of active sites for nitric acid chemistry on soot. Since atmospheric heterogeneous reactions that exhibit surface deactivation may, in principle, affect trace gas concentration, we perform an assessment in this regard. C1 Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Pacific NW Lab, Atmospher Sci Tech Grp, Richland, WA 99352 USA. RP Disselkamp, RS (reprint author), Pacific NW Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. NR 29 TC 22 Z9 24 U1 2 U2 11 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD OCT PY 2000 VL 37 IS 2 BP 113 EP 123 DI 10.1023/A:1006304724241 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 337KM UT WOS:000088357400001 ER PT J AU Vajjhala, S Kraynik, AM Gibson, LJ AF Vajjhala, S Kraynik, AM Gibson, LJ TI A cellular solid model for modulus reduction due to resorption of trabeculae in bone SO JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID ELASTIC PROPERTIES; NONPERIODIC MICROSTRUCTURE; BEHAVIOR AB In osteoporotic trabecular bone, bone loss occurs by thinning and subsequent resorption of the trabeculae. In this study, we compare the effects of density reductions from uniform thinning of struts or from removal of struts in a random, open-cell, three-dimensional Voronoi structure. The results of this study, combined with those previous studies on other regular and random structures, suggest that the modulus and strength of trabecular bone are reduced more dramatically by density losses from resorption of trabeculae than by those from uniform thinning of trabeculae. [S0148-0731(00)00805-0]. C1 MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Vajjhala, S (reprint author), MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RI Gibson, Lorna/K-4738-2012; OI /0000-0001-7559-7815 FU NIAMS NIH HHS [AR 41894-0182] NR 22 TC 40 Z9 42 U1 1 U2 9 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0148-0731 J9 J BIOMECH ENG-T ASME JI J. Biomech. Eng.-Trans. ASME PD OCT PY 2000 VL 122 IS 5 BP 511 EP 515 DI 10.1115/1.1289996 PG 5 WC Biophysics; Engineering, Biomedical SC Biophysics; Engineering GA 404QD UT WOS:000167111200008 PM 11091953 ER PT J AU Mullins, DR Kundakovic, L Overbury, SH AF Mullins, DR Kundakovic, L Overbury, SH TI The interaction between NO and CO on Rh-loaded CeOx(111) SO JOURNAL OF CATALYSIS LA English DT Article DE CO; carbon monoxide; NO; nitric oxide; OCN; isocyanate; ceria; CeO2; rhodium; X-ray photoelectron spectroscopy; temperature-programmed desorption ID ELECTRON-SPECTROSCOPY; NITRIC-OXIDE; SURFACES; RH(111); CARBON; REDUCTION; RHODIUM; XPS; CHEMISORPTION; ETHYLENE AB We have used SXPS and TPD to probe the interactions between CO and NO on ceria-supported Rh model catalysts (Rh/CeOx). On a highly reduced ceria substrate the only desorption products were CO and N-2. No NO or CO2 were observed, as have been seen on Rh single-crystal surfaces. The desorption profiles of the CO and N-2: were much different than the desorption spectra from CO or NO adsorbed alone, suggesting a strong interaction between the CO and NO. C 1s, N 1s, and O 1s photoemission spectra were recorded to determine the surface intermediates. There is little interaction between the CO and NO below 400 K. Near 400 K the CO reacts with atomic N from dissociated NO to form OCN. The isocyanate dissociates near 600 K, producing desorbed CO and carbon-nitrogen species, CXNY, on the surface. The CXNY decomposes above 700 K to produce CO and N-2. The reduced ceria substrate introduces several reaction paths that help promote reactions not ordinarily observed on pure Rh. The reduced ceria removes O from the Rh. This inhibits: the formation of CO2 and promotes OCN formation. The reduced ceria also promotes the dissociation of CO. After dissociation, the O is removed by the ceria and the atomic C and N react, forming CXNY. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Mullins, DR (reprint author), Oak Ridge Natl Lab, POB 2008,MS 6201, Oak Ridge, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 30 TC 27 Z9 27 U1 2 U2 12 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD OCT 1 PY 2000 VL 195 IS 1 BP 169 EP 179 DI 10.1006/jcat.2000.2983 PG 11 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 363KP UT WOS:000089835100019 ER PT J AU Pan, JW Rothman, DL Behar, KL Stein, DT Hetherington, HP AF Pan, JW Rothman, DL Behar, KL Stein, DT Hetherington, HP TI Human brain beta-hydroxybutyrate and lactate increase in fasting-induced ketosis SO JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM LA English DT Article DE ketone body; brain metabolism; lactate; fasting; energetics ID MAGNETIC-RESONANCE SPECTROSCOPY; KETONE-BODY UTILIZATION; HUMAN VISUAL-CORTEX; RAT-BRAIN; GLUCOSE-UTILIZATION; STARVATION; STIMULATION; METABOLISM; GLUTAMATE; H-1-NMR AB Ketones are known to constitute an important fraction of fuel for consumption by the brain, with brain ketone content generally thought to be low. However, the recent observation of 1-mmol/L levels of brain beta-hydroxybutyrate (BHB) in children on the ketogenic diet suggests otherwise. The authors report the measurement of brain BHB and lactate in the occipital lobe of healthy adults using high field (4-T) magnetic resonance spectroscopy, measured in the nonfasted state and after 2- and 3-day fasting-induced ketosis. A 9-mL voxel located in the calcarine Fissure was studied, detecting the BHB and lactate upfield resonances using a H-1 homonuclear editing sequence. Plasma BHB levels also were measured. The mean brain BHB concentration increased from a nonfasted level of 0.05 +/- 0.05 to 0.60 +/- 0.26 mmol/L (after second day of fasting), increasing further to 0.98 +/- 0.16 mmol/L (after the third day of fasting). The mean nonfasted brain lactate was 0.69 +/- 0.17 mmol/L, increasing to 1.47 +/- 0.22 mmol./L after the third day. The plasma and brain BHB levels correlated well (r = 0.86) with a brain-plasma slope of 0.26. These data show that brain BHB rises significantly with 2- and 3-day fasting-induced ketosis. The lactate increase likely results from ketones displacing lactate oxidation without altering glucose phosphorylation and glycolysis. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. Yale Univ, Dept Radiol, New Haven, CT USA. Yale Univ, Dept Neurol, New Haven, CT USA. Albert Einstein Coll Med, Dept Med, Bronx, NY 10467 USA. RP Pan, JW (reprint author), Brookhaven Natl Lab, Dept Med, 30 Bell Ave, Upton, NY 11973 USA. FU NCRR NIH HHS [1MO1RR12248]; NICHD NIH HHS [P01-HD-32573]; NINDS NIH HHS [R01-NS-32126] NR 34 TC 56 Z9 58 U1 0 U2 5 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0271-678X J9 J CEREBR BLOOD F MET JI J. Cereb. Blood Flow Metab. PD OCT PY 2000 VL 20 IS 10 BP 1502 EP 1507 PG 6 WC Endocrinology & Metabolism; Hematology; Neurosciences SC Endocrinology & Metabolism; Hematology; Neurosciences & Neurology GA 360WN UT WOS:000089690500012 PM 11043913 ER PT J AU Geske, GD Boldyrev, AI Li, X Wang, LS AF Geske, GD Boldyrev, AI Li, X Wang, LS TI On the origin of planarity in Al-5(-) and Al-5 clusters: The importance of a four-center peripheral bond SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SMALL ALUMINUM CLUSTERS; COLLISION-INDUCED DISSOCIATION; S-P HYBRIDIZATION; SHELL STRUCTURE; ELECTRONIC-STRUCTURE; PHOTOELECTRON-SPECTROSCOPY; AB-INITIO; ENERGIES; IONS; CARBON AB Ab initio calculations were combined with anion photoelectron spectroscopy to unravel the structural origin of Al-5 and Al-5(-). Well-resolved photoelectron spectra of Al-5(-) were obtained and compared to theoretical calculations performed at various levels of theory. It was shown that the best agreement between the experimental and theoretical data is for a planar C-2v structure. Analyses of the electronic structure and molecular orbitals revealed that the planarity in Al-5 and Al-5(-) are due to the presence of a four-center peripheral bond that is common in a whole family of planar pentaatomic species recently uncovered. (C) 2000 American Institute of Physics. [S0021-9606(00)01837-7]. C1 Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA. Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Geske, GD (reprint author), Utah State Univ, Dept Chem & Biochem, Logan, UT 84322 USA. RI Boldyrev, Alexander/C-5940-2009 OI Boldyrev, Alexander/0000-0002-8277-3669 NR 44 TC 46 Z9 48 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 OCT 1 PY 2000 VL 113 IS 13 BP 5130 EP 5133 AR PII [S0021-9606(00)01837-7] DI 10.1063/1.1311966 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 354TC UT WOS:000089344900005 ER PT J AU Schenter, GK Garrett, BC Voth, GA AF Schenter, GK Garrett, BC Voth, GA TI The quantum vibrational dynamics of Cl-(H2O)(n) clusters SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CENTROID MOLECULAR-DYNAMICS; LIQUID PARA-HYDROGEN; WATER CLUSTERS; EXCESS PROTON; ALGORITHMS; SPECTROSCOPY; SIMULATION; EQUILIBRIUM; FORMULATION; COMPLEXES AB The centroid molecular dynamics technique is applied to the case of chloride-water clusters to estimate their finite temperature quantum vibrational structure. We employ the flexible RWK2 water potential [J. R. Reimers, R. O. Watts, and M. L. Klein, Chem. Phys. 64, 95 (1982)] and the parametrization of a chloride-water interaction potential of Dorsett, Watts and Xantheas [J. Phys. Chem. A 103, 3351 (1999)]. We then investigate the temperature-dependent vibrational structure (infrared spectra). We find that the centroid molecular dynamics technique is capable of recovering a majority of the red shift associated with hydrogen bonding. (C) 2000 American Institute of Physics. [S0021-9606(00)51737-1]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Utah, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. RP Schenter, GK (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RI Garrett, Bruce/F-8516-2011; Schenter, Gregory/I-7655-2014 OI Schenter, Gregory/0000-0001-5444-5484 NR 50 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 2000 VL 113 IS 13 BP 5171 EP 5178 AR PII [S0021-9606(00)51737-1] DI 10.1063/1.1290132 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 354TC UT WOS:000089344900012 ER PT J AU Baldelli, S Eppler, AS Anderson, E Shen, YR Somorjai, GA AF Baldelli, S Eppler, AS Anderson, E Shen, YR Somorjai, GA TI Surface enhanced sum frequency generation of carbon monoxide adsorbed on platinum nanoparticle arrays SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID AGGREGATED SILVER FILMS; RAMAN-SCATTERING; 2ND-HARMONIC GENERATION; SPECTROSCOPY; MOLECULES; PARTICLES AB Sum frequency generation (SFG) vibrational spectroscopy is used to study the adsorption of CO at similar to 1 atm pressure on Pt nanoparticle arrays and Pt thin films. The SFG signal of CO adsorbed on platinum particles of 45 nm diameter is similar to 10 000 times larger than from CO on smooth Pt films. The large enhancement is explained by plasmon resonance and Maxwell-Garnett theory. The Pt arrays are prepared using electron beam lithography to produce particles with uniform spacing and sizes on an oxidized Si(100) wafer. Further, as the Pt coverage increases the SFG signal shows a polarization dependence that is explained considering the dielectric properties of a metal film on a dielectric surface. In addition, SFG permits investigation of the CO adsorbed on the particles at similar to 1 atm, which is not possible with most surface analytical techniques, that will allow for the study of the reaction of small molecules on surfaces relevant in heterogeneous catalysis. (C) 2000 American Institute of Physics. [S0021-9606(00)70437-5]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Baldelli, S (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 32 TC 81 Z9 82 U1 8 U2 37 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 OCT 1 PY 2000 VL 113 IS 13 BP 5432 EP 5438 DI 10.1063/1.1290024 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 354TC UT WOS:000089344900039 ER PT J AU Halpern, AL AF Halpern, AL TI Comparison of papillomavirus and immunodeficiency virus evolutionary patterns in the context of a papillomavirus vaccine SO JOURNAL OF CLINICAL VIROLOGY LA English DT Article; Proceedings Paper CT HPV Vaccination Workshop on Vaccinating Women again st Premature Death CY JAN 10, 2000 CL HELSINKI, FINLAND SP Acad Finland, Finnish Med Assoc DE cross-protection; host-linked evolution; mutation rate; population bottleneck; selection; vaccine escape; zoonosis ID NUCLEOTIDE-SEQUENCE ANALYSIS; RENAL-TRANSPLANT RECIPIENTS; TYPE-16 VARIANT LINEAGES; CAPSID PROTEIN GENES; EPIDERMODYSPLASIA-VERRUCIFORMIS; WORLDWIDE PERSPECTIVE; IDENTIFICATION; CANCERS; HIV-1; RISK AB In contemplating a vaccine for human papillomaviruses (HPVs), it is important to consider the evolutionary context in which such a vaccine would be deployed. The human immunodeficiency virus, having been the subject of even more extensive study than HPV, shares certain salient features with regards to phylogenetic structure, and may serve as a model for contemplation of possible difficulties with HPV vaccination. However, there are also striking differences in the evolutionary potentials and histories of the viruses that permit an optimistic outlook for HPV. These similarities and differences, as well as their implications for vaccination studies, are reviewed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ New Mexico, Dept Mol Genet & Microbiol, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Halpern, AL (reprint author), Celera Genom, 45 W Gude Dr, Rockville, MD 20850 USA. NR 63 TC 27 Z9 27 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-6532 J9 J CLIN VIROL JI J. Clin. Virol. PD OCT PY 2000 VL 19 IS 1-2 SI SI BP 43 EP 56 DI 10.1016/S1386-6532(00)00127-X PG 14 WC Virology SC Virology GA 377VM UT WOS:000165547000006 PM 11091147 ER PT J AU Pernpointner, M Visscher, L De Jong, WA Broer, R AF Pernpointner, M Visscher, L De Jong, WA Broer, R TI Parallelization of four-component calculations. I. Integral generation, SCF, and four-index transformation in the Dirac-Fock package MOLFDIR SO JOURNAL OF COMPUTATIONAL CHEMISTRY LA English DT Article DE four-component calculations; Dirac-Fock correlations ID GAUSSIAN-BASIS SETS; MOLECULAR SYMMETRY; PROGRAM; CLUSTER AB The treatment of relativity and electron correlation on an equal footing is essential for the computation of systems containing heavy elements. Correlation treatments that are based on four-component Dirac-Hartree-Fock calculations presently provide the most accurate, albeit costly, way of taking relativity into account. The requirement of having two expansion basis sets for the molecular wave function puts a high demand on computer resources. The treatment of larger systems is thereby often prohibited by the very large run times and files that arise in a conventional Dirac-Hartree-Fock approach. A possible solution for this bottleneck is a parallel approach that not only reduces the turnaround time but also spreads out the large files over a number of local disks. Here, we present a distributed-memory parallelization of the program package MOLFDIR for the integral generation, Dirac-Hartree-Fock and four-index MS transformation steps. This implementation scales best for large AO spaces and moderately sized active spaces. (C) 2000 John Wiley & Sons, Inc. C1 Vrije Univ Amsterdam, Fac Sci, Div Chem, NL-1081 HV Amsterdam, Netherlands. Univ Groningen, Ctr Mat Sci, NL-9747 AG Groningen, Netherlands. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Visscher, L (reprint author), Vrije Univ Amsterdam, Fac Sci, Div Chem, Boelelaan 1083, NL-1081 HV Amsterdam, Netherlands. EM visscher@chem.vu.nl RI DE JONG, WIBE/A-5443-2008; Visscher, Lucas/A-3523-2010 OI DE JONG, WIBE/0000-0002-7114-8315; Visscher, Lucas/0000-0002-7748-6243 NR 38 TC 21 Z9 21 U1 1 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0192-8651 J9 J COMPUT CHEM JI J. Comput. Chem. PD OCT PY 2000 VL 21 IS 13 BP 1176 EP 1186 DI 10.1002/1096-987X(200010)21:13<1176::AID-JCC6>3.0.CO;2-E PG 11 WC Chemistry, Multidisciplinary SC Chemistry GA 360UP UT WOS:000089685900006 ER PT J AU Resat, H Sungur, FA Baginski, M Borowski, E Aviyente, V AF Resat, H Sungur, FA Baginski, M Borowski, E Aviyente, V TI Conformational properties of amphotericin B amide derivatives - impact on selective toxicity SO JOURNAL OF COMPUTER-AIDED MOLECULAR DESIGN LA English DT Article DE Amphotericin B; amide derivatives of Amphotericin B; cholesterol; conformational analysis; drug design; ergosterol; membrane ion channel; potential energy surface; semiempirical quantum chemistry methods ID POLYENE MACROLIDE ANTIBIOTICS; MOLECULAR-DYNAMICS; PHOSPHOLIPID-COMPOSITION; STEROL STRUCTURE; METHYL-ESTER; CHOLESTEROL; WATER; AGGREGATION; ERGOSTEROL; LIPOSOMES AB Even though it is highly toxic, Amphotericin B (AmB), an amphipathic polyene macrolide antibiotic, is used in the treatment of severe systemic fungal infections as a life-saving drug. To examine the influence of conformational factors on selective toxicity of these compounds, we have investigated the conformational properties of five AmB amide derivatives. It was found that the extended conformation with torsional angles (phi,psi)=(290 degrees,180 degrees ) is a common minimum of the potential energy surfaces (PES) of unsubstituted AmB and its amide derivatives. The extended conformation of the studied compounds allows for the formation of an intermolecular hydrogen bond network between adjacent antibiotic molecules in the open channel configuration. Therefore, the extended conformation is expected to be the dominant conformer in an open AmB (or its amide derivatives) membrane channel. The derivative compounds for calculations were chosen according to their selective toxicity compared to AmB and they had a wide range of selective toxicity. Except for two AmB derivatives, the PES maps of the derivatives reveal that the molecules can coexist in more than one conformer. Taking into account the cumulative conclusions drawn from the earlier MD simulation studies of AmB membrane channel, the results of the potential energy surface maps, and the physical considerations of the molecular structures, we hypothesize a new model of structure-selective toxicity of AmB derivatives. In this proposed model the presence of the extended conformation as the only well defined global conformer for AmB derivatives is taken as the indicator of their higher selective toxicity. This model successfully explains our results. To further test our model, we also investigated an AmB derivative whose selective toxicity has not been experimentally measured before. Our prediction for the selective toxicity of this compound can be tested in experiments to validate or invalidate the proposed model. C1 Koc Univ, Sch Arts & Sci, Istinye Istanbul, Turkey. Bogazici Univ, Dept Chem, TR-80815 Bebek, Istanbul, Turkey. Gdansk Univ Technol, Dept Pharmaceut Technol & Biochem, PL-80952 Gdansk, Poland. RP Resat, H (reprint author), Pacific NW Natl Lab, POB 999,MS K2-21, Richland, WA 99352 USA. EM haluk.resat@pnl.gov RI Baginski, Maciej/C-9201-2011; Sungur-Konuklar, Fethiye Aylin/L-8764-2015; Aviyente, Viktorya/Q-2759-2015 OI Sungur-Konuklar, Fethiye Aylin/0000-0003-3245-742X; Aviyente, Viktorya/0000-0001-9430-4096 NR 49 TC 23 Z9 24 U1 1 U2 8 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0920-654X EI 1573-4951 J9 J COMPUT AID MOL DES JI J. Comput.-Aided Mol. Des. PD OCT PY 2000 VL 14 IS 7 BP 689 EP 703 DI 10.1023/A:1008144208706 PG 15 WC Biochemistry & Molecular Biology; Biophysics; Computer Science, Interdisciplinary Applications SC Biochemistry & Molecular Biology; Biophysics; Computer Science GA 351BX UT WOS:000089137100007 PM 11008890 ER PT J AU Mayes, MA Jardine, PM Larsen, IL Brooks, SC Fendorf, SE AF Mayes, MA Jardine, PM Larsen, IL Brooks, SC Fendorf, SE TI Multispecies transport of metal-EDTA complexes and chromate through undisturbed columns of weathered fractured saprolite SO JOURNAL OF CONTAMINANT HYDROLOGY LA English DT Article DE chelation; disequilibrium; heterogeneity; preferential flow; cobalt; cadmium ID CO(II/III)EDTA REACTIVE TRANSPORT; CATALYZED CHROMIUM(VI) REDUCTION; SELF-ABSORPTION CORRECTIONS; HETEROGENEOUS POROUS-MEDIA; 2 CONTRASTING WATERSHEDS; MASS-TRANSFER; HEXAVALENT CHROMIUM; FLOW INTERRUPTION; GRAVEL AQUIFER; ORGANIC-CARBON AB Laboratory-scale tracer experiments were conducted to investigate the geochemical and hydrological processes that govern the fate and transport of organically chelated radionuclides and toxic metals in undisturbed saturated columns of weathered, fractured shale saprolite. Three long-term, reactive contaminant injections were pulsed onto three separate soil columns, with the following influent mixtures: (1) (109)CdEDTA(2-), (2) (109)CdEDTA(2-) and Co-57,Co-58(II)EDTA(2-), and (3) (109)CdEDTA(2-), Co-57(III)EDTA(-), and (HCrO4-)-Cr-51. Both single and multiple species experiments were conducted to determine the importance of interaction between the contaminants and competition for surface sites. Flow interruption was used to identify physical and chemical non-equilibrium (PNE and CNE) which were caused by multiple pore-region flow and rate-limited chemical reactions, respectively. Reactive contaminant transport through the fractured, weathered shale was affected by sorption, redox, and dissociation reactions, which were mediated by soil organic matter and surficial oxides of Fe, Mn, and Al. The transport of CdEDTA(2-) was significantly influenced by ligand-promoted dissolution of subsurface Fe and Al sources, resulting in the liberation of Cd2+, Al(III)EDTA(-) and Fe(III)EDTA(-). Flow interruption confirmed that the surface-mediated dissociation reaction was time-dependent, with the stability of the CdEDTA(2-) complex dependent on its residence time within the soil. The migration of Co(II)EDTA(2-) was dominated by oxidization to the highly stable Co(III)EDTA(-) species, and elevated effluent Mn2+ suggested that surficial Mn(IV) oxides likely catalyzed the redox reaction, though Fe-oxides may have also contributed to the reaction. Dissociation (12%) of the Co(II)EDTA(2-) complex was first observed during flow interruption indicating that rate-limited dissociation of the complex by Fe-oxides may be significant under equilibrium conditions. The transport of HCrO4- was significantly altered by the reduction of mobile Cr(VI) to irreversibly bound Cr(III). The reduction reaction was catalyzed by surface-bound natural organic matter and flow interruption confirmed that the reaction was time-dependent. There was little evidence of competitive effects between the various contaminants in the multispecies experiments, since each was influenced by a different geochemical process during transport through the soil. The results of this study further support research findings that suggest anionic toxic metals and radionuclide-organic complexes can be significantly influenced by soil geochemical processes that can both enhance and impede the subsurface migration of these contaminants. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. RP Mayes, MA (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Brooks, Scott/B-9439-2012 OI Brooks, Scott/0000-0002-8437-9788 NR 62 TC 40 Z9 42 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7722 J9 J CONTAM HYDROL JI J. Contam. Hydrol. PD OCT PY 2000 VL 45 IS 3-4 BP 243 EP 265 DI 10.1016/S0169-7722(00)00108-X PG 23 WC Environmental Sciences; Geosciences, Multidisciplinary; Water Resources SC Environmental Sciences & Ecology; Geology; Water Resources GA 364XH UT WOS:000089919000002 ER PT J AU Lu, SW Lee, BI Wang, ZL Samuels, WD AF Lu, SW Lee, BI Wang, ZL Samuels, WD TI Hydrothermal synthesis and structural characterization of BaTiO3 nanocrystals SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE hydrothermal method; barium titanate; nanocrystals; cubic-to-tetragonal transition; strains; Raman spectroscopy ID BARIUM-TITANATE POWDERS; DIELECTRIC-PROPERTIES; TETRAGONAL BATIO3; CRYSTAL-STRUCTURE; ROOM-TEMPERATURE; PARTICLE-SIZE; FINE POWDERS; DEPENDENCE; PRECURSOR AB Barium titanate (BaTiO3:BT) nanocrystals were tailored by hydrothermal method in the presence of polyoxyethylene (20) sorbitan monooleate (Tween(R) 80) as a polymeric surface modifier at 230 degrees C for 0.5-2 h. The mean particle size was 77.8 +/- 23.5 nm by transmission electron microscopy (TEM), and 83 +/- 19 nm by laser-scattering particle size analyzer. The narrow particle size distribution of the nanocrystals suggested that further growth and agglomeration of crystals have been hindered by the surface modifier. These nanocrystals were identified as metastable cubic phase BT by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). However, Raman-active modes of tetragonal phase BT were detected from Raman spectra of as-prepared nanocrystals. Large strains have been observed in TEM dark field image, indicative of a structural deformation from metastable cubic phase to tetragonal phase. The results suggest that the hydrothermally synthesized BT nanocrystals are metastable cubic phase with some tetragonality. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Clemson Univ, Dept Ceram & Mat Engn, Clemson, SC 29634 USA. Georgia Inst Technol, Sch Mat Sci & Engn, Atlanta, GA 30332 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Lee, BI (reprint author), Clemson Univ, Dept Ceram & Mat Engn, Olin Hall,POB 340907, Clemson, SC 29634 USA. RI Wang, Zhong Lin/E-2176-2011 OI Wang, Zhong Lin/0000-0002-5530-0380 NR 41 TC 139 Z9 148 U1 12 U2 107 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD OCT PY 2000 VL 219 IS 3 BP 269 EP 276 PG 8 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 364ZG UT WOS:000089923500011 ER PT J AU Winarski, RP Eskildsen, T Stadler, S van Ek, J Ederer, DL Kurmaev, EZ Grush, MM Callcott, TA Moewes, A Lee, M AF Winarski, RP Eskildsen, T Stadler, S van Ek, J Ederer, DL Kurmaev, EZ Grush, MM Callcott, TA Moewes, A Lee, M TI The effects of boron impurities on the atomic bonding and electronic structure of Ni3Al SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE boron impurities; atomic bonding; electronic structure; Ni3Al ID RAY FLUORESCENCE SPECTROSCOPY; EMISSION AB Tunable synchrotron radiation was used to examine the boron K-valence emission from boron doped Ni3Al (500 parts per million boron). When compared with electronic structure calculations these measurements yield information regarding the local bonding environment of the doped boron atoms within the alloy structure. Our measurements appear to suggest that the boron atoms preferentially bond with the nickel atoms in this material. It seems that the boron atoms prefer to occupy octahedral interstitial sites surrounded by six nickel atoms. This suggests that the enhancement in ductility observed in this alloy is due to the interplanar metallic bonding provided by the doped boron atoms. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Russian Acad Sci, Inst Met Phys, Ural Div, Ekaterinburg 620219, Russia. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Louisiana State Univ, Ctr Adv Microstruct & Devices, Baton Rouge, LA 70803 USA. RP Argonne Natl Lab, XFD, 9700 S Cass Ave, Argonne, IL 60439 USA. EM winarski@aps.anl.gov RI Kurmaev, Ernst/J-4254-2013 OI Kurmaev, Ernst/0000-0003-4625-4930 NR 19 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 EI 1873-2526 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD OCT PY 2000 VL 110 IS 1-3 SI SI BP 69 EP 74 DI 10.1016/S0368-2048(00)00157-2 PG 6 WC Spectroscopy SC Spectroscopy GA 362JH UT WOS:000089774500005 ER PT J AU Stadler, S Winarski, RP MacLaren, JM Ederer, DL vanEk, J Moewes, A Grush, MM Callcott, TA Perera, RCC AF Stadler, S Winarski, RP MacLaren, JM Ederer, DL vanEk, J Moewes, A Grush, MM Callcott, TA Perera, RCC TI Electronic structures of the tungsten borides WB, W2B and W2B5 SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article ID ADVANCED LIGHT-SOURCE; X-RAY FLUORESCENCE; BEAMLINE AB The electronic structures of the tungsten borides WB, W2B and W2B5 were studied experimentally and theoretically. Using monochromatic synchrotron radiation as the excitation source, soft X-ray emission and absorption spectroscopic techniques were employed to probe the occupied and unoccupied states of the valence band, respectively. The linear muffin-tin orbital method was used to calculate the ground state electronic properties of these compounds. The experimental spectroscopic data and the calculated angular momentum- and site-projected densities of states yielded new useful information regarding bonding and hybridization in these materials. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Seagate Recording Heads, Bloomington, MN 55435 USA. Louisiana State Univ, Ctr Adv Microstruct & Devices, Baton Rouge, LA 70803 USA. Univ Tennessee, Knoxville, TN 37996 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Tulane Univ, Dept Phys, 2001 Percival Stem Hall, New Orleans, LA 70118 USA. EM stadler@theochem.kth.se NR 17 TC 20 Z9 20 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 EI 1873-2526 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD OCT PY 2000 VL 110 IS 1-3 SI SI BP 75 EP 86 DI 10.1016/S0368-2048(00)00158-4 PG 12 WC Spectroscopy SC Spectroscopy GA 362JH UT WOS:000089774500006 ER PT J AU Carlisle, JA Blankenship, SR Terminello, LJ Jia, JJ Callcott, TA Ederer, DL Perera, RCC Himpsel, FJ AF Carlisle, JA Blankenship, SR Terminello, LJ Jia, JJ Callcott, TA Ederer, DL Perera, RCC Himpsel, FJ TI Crystal-momentum-resolved electronic structure of solids using resonant soft-X-ray fluorescence spectroscopy SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article DE X-ray emission spectra; resonant X-ray scattering; band structure; excitons; graphite; hexagonal boron nitride ID BAND-STRUCTURE; INELASTIC-SCATTERING; GRAPHITE; ABSORPTION; EMISSION; EXCITONS AB Resonant inelastic X-ray scattering (RIXS) has been observed in graphite and hexagonal boron nitride (hBN) above and below their K edges. Below the core threshold, inelastic-loss features are observed, which disperse linearly with excitation energy, but as the excitation goes above the core binding energy, nonlinear dispersive effects are observed in graphite but not in hBN. We show that these two effects, which have previously been thought of as separate processes, i.e. resonant X-ray Raman scattering (below threshold) and RMS (above threshold), are in fact described by the same physics of coherent fluorescence. Very good agreement between experiment and simulated RIXS is achieved using a simple one-electron framework. The role core-excitons play in the RIXS process is examined in finer detail, by using narrow-band excitation. Our results indicate that core-hole effects play a minor role in the RIXS observed from graphite but are more pronounced in hBN. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Virginia Commonwealth Univ, Richmond, VA 23284 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Tennessee, Knoxville, TN 37996 USA. Tulane Univ, New Orleans, LA 70118 USA. Lawrence Berkeley Natl Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Carlisle, JA (reprint author), Virginia Commonwealth Univ, Med Coll Virginia Campus, Richmond, VA 23284 USA. NR 25 TC 25 Z9 25 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD OCT PY 2000 VL 110 IS 1-3 SI SI BP 323 EP 334 DI 10.1016/S0368-2048(00)00171-7 PG 12 WC Spectroscopy SC Spectroscopy GA 362JH UT WOS:000089774500019 ER PT J AU Minor, AM Morris, JW AF Minor, AM Morris, JW TI Inhibiting growth of the Au0.5Ni0.5Sn4 intermetallic layer in Pb-Sn solder joints reflowed on Au/Ni metallization SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT Annual 2000 TMS Meeting CY MAR 12-16, 2000 CL NASHVILLE, TENNESSEE SP Miner, Met & Mat Soc, Extract & Process Div DE solder; intermetallic; Au/Ni metallization; AuSn4; Ni3Sn4; Au0.5Ni0.5Sn ID AU FOILS AB Au/Ni metallization has become increasingly common in microelectronic packaging when Cu pads are joined with Pb-Sn solder. Recent work has shown that a ternary compound with stoichiometry Au0.5Ni0.5Sn4 redeposits onto the interface during aging, compromising the strength of the joint. In the present work the growth of the Au0.5Ni0.5Sn4 layer is documented and methods for inhibiting its growth were investigated. It was determined that multiple reflows, both with and without additional aging, can substantially limit the thickness of the ternary layer. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 USA. RP Minor, AM (reprint author), Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. NR 12 TC 60 Z9 63 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD OCT PY 2000 VL 29 IS 10 BP 1170 EP 1174 DI 10.1007/s11664-000-0009-4 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 364LU UT WOS:000089894500009 ER PT J AU Foley, JC Gickler, A Leprevost, FH Brown, D AF Foley, JC Gickler, A Leprevost, FH Brown, D TI Analysis of ring and plug shear strengths for comparison of lead-free solders SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT Annual 2000 TMS Meeting CY MAR 12-16, 2000 CL NASHVILLE, TENNESSEE SP Miner, Met & Mat Soc, Extract & Process Div DE lead-free solders; shear strength; ring and plug joints AB The drive to replace the use of toxic lead metal and its alloys has spurred the development of many new lead-free solder alloys. Moreover, current leaded solders lack shear strength, resistance to creep and to thermal-mechanical fatigue. Solder that exhibits enhancements of these properties and retains solderability is crucial in applications where the solder joints are subjected to thermal cycling, severe vibrations, and temperatures of up to 125 degrees C. Modified ring and plug joints were made with 18 selected lead-free solders and three well characterized lead-containing solders. Analysis of the results provides a guide for the design of additional testing. C1 Ames Lab, Ames, IA 50011 USA. Johnson Mfg Co, Princeton, IA 52768 USA. RP Foley, JC (reprint author), Ames Lab, Ames, IA 50011 USA. NR 5 TC 33 Z9 35 U1 1 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD OCT PY 2000 VL 29 IS 10 BP 1258 EP 1263 DI 10.1007/s11664-000-0021-8 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 364LU UT WOS:000089894500021 ER PT J AU Brodzinski, R AF Brodzinski, R TI The "discovery" of alpha activity in lead and solder SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT Annual 2000 TMS Meeting CY MAR 12-16, 2000 CL NASHVILLE, TENNESSEE SP Miner, Met & Mat Soc, Extract & Process Div DE low-alpha lead; flip-chip soft errors AB More than 15 years ago the presence of Pb-210 activity in lead was found to create significant background in a low-background radiation detection spectrometer. Shortly thereafter, Po-210 alpha particles emitted from the surface of a solder joint were directly observed with this spectrometer. Antiquity lead was used to eliminate these sources of radioactivity. The experiments leading up to these "discoveries" are described. The magnitude of the effect of Pb-210 in lead on the experiment is discussed. The sensitivities of various techniques for measuring Pb-210 in lead are compared, and a practical limit for alpha activity in lead is proposed. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Brodzinski, R (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD OCT PY 2000 VL 29 IS 10 BP 1294 EP 1298 DI 10.1007/s11664-000-0028-1 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 364LU UT WOS:000089894500028 ER PT J AU Ricart, LM Reltz, RD Dec, JE AF Ricart, LM Reltz, RD Dec, JE TI Comparisons of diesel spray liquid penetration and vapor fuel distributions with in-cylinder optical measurements SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article ID COMBUSTION; MODELS AB The performance of two spray models for predicting liquid and vapor fuel distribution, combustion and emissions is investigated. The model predictions are compared with extensive data from in-cylinder laser diagnostics carried out in an optically accessible heavy-duty D. I. diesel engine over a wide range of operating conditions. Top-dead center temperature and density were varied between 800 K and 1100 K and II,I and 33.2kg/m(3), respectively Two spray breakup mechanisms were considered: due to Kelvin-Helmholtz (KH) instabilities and to Rayleigh-Taylor (RT) instabilities. Comparisons of a wide range of parameters, which include in-cylinder pressure, apparent heat release rate, liquid fuel penetration, vapor distribution and soot distribution, have shown that a combination of the KH and the RT mechanisms gives realistic predictions. In particular, the limited liquid fuel penetration observed experimentally was captured by including these two competing mechanisms in the spray model. Furthermore, the penetration of the vapor fuel ahead of the liquid spray was also captured. A region of high soot concentration at the spray rip was observed experimentally and also predicted by the KH-RT spray breakup model. C1 Univ Wisconsin, Engine Res Ctr, Madison, WI 53706 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94550 USA. RP Ricart, LM (reprint author), Univ Wisconsin, Engine Res Ctr, Madison, WI 53706 USA. NR 26 TC 42 Z9 44 U1 4 U2 10 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD OCT PY 2000 VL 122 IS 4 BP 588 EP 595 DI 10.1115/1.1290591 PG 8 WC Engineering, Mechanical SC Engineering GA 404QH UT WOS:000167111700012 ER PT J AU Skoug, RM Feldman, WC Gosling, JT McComas, DJ Smith, CW AF Skoug, RM Feldman, WC Gosling, JT McComas, DJ Smith, CW TI Solar wind electron characteristics inside and outside coronal mass ejections SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC CLOUDS; HEAT-FLUX DROPOUTS; NONLINEAR EVOLUTION; POLYTROPIC INDEX; VOYAGER 2; TEMPERATURE; PLASMA; FIELD; ULYSSES; EVENTS AB We present a study of 9 months of data from the solar wind plasma electron instrument on the ACE spacecraft. Electron pitch angle distributions were used to identify intervals of counterstreaming halo electrons, which were observed similar to 16% of the time that the spacecraft was not magnetically connected to the Earth's bow shock. Counterstreaming electrons presumably indicate a closed magnetic field topology and thus indicate the passage of coronal mass ejections (CMEs) in the solar wind. In this study, we separately examine electron moments at times with and without counterstreaming electrons, including both magnetic clouds and noncloud CMEs. The properties of both the core and halo electron populations were nearly identical at times with and without counterstreaming electrons. Both low and high electron densities and temperatures were observed in either type of event. In contrast, magnetic clouds, on average, showed increased densities and reduced temperatures. The core/halo density ratio and the total electron density were anticorrelated in all cases, indicating that the halo contributes more to the total electron density at low density times, regardless of magnetic topology. Total electron temperature anal density were anticorrelated in all types of events. This consistent anticorrelation implies that such single-spacecraft measurements of temperature and density cannot be used to determine a polytropic index for solar wind electrons. Instead, the anticorrelation may be due to pressure balance of the solar wind plasma or may be a remnant of coronal conditions. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Skoug, RM (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop D466, Los Alamos, NM 87545 USA. NR 54 TC 33 Z9 33 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-SPACE JI J. Geophys. Res-Space Phys. PD OCT 1 PY 2000 VL 105 IS A10 BP 23069 EP 23084 DI 10.1029/2000JA000017 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 359UN UT WOS:000089630600010 ER PT J AU Hilmer, RV Ginet, GP Cayton, TE AF Hilmer, RV Ginet, GP Cayton, TE TI Enhancement of equatorial energetic electron fluxes near L=4.2 as a result of high speed solar wind streams SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID RELATIVISTIC ELECTRONS; RADIATION BELT; MAGNETIC-FIELD; GEOSYNCHRONOUS ORBIT; OUTER MAGNETOSPHERE; GEOMAGNETIC STORMS; PROTONS; ZONE; ACCELERATION; PREDICTION AB We examine the relationship of energetic equatorial electron flux enhancements occurring near L = 4.2 and 6.6 associated with 26 well-defined high-speed solar wind streams (HSSWS) detected by Wind between December 1994 and September 1996. Events were selected for having high-energy (>2 MeV) geosynchronous electron daily average fluxes surpassing 10(3) cm(-2) s(-1) sr(-1) for at least a day as measured by GOES 7 or GOES 9. Los Alamos differential-energy electron data fi-om SOFA (0.2 - 2.0 MeV) at L = 6.6 and the GPS BDD-II dosimeters (0.2 - 3.2 MeV) at L = 4.2 illustrate that flux dropouts are typically observed in all energy channels at both equatorial altitudes within the fil st day of each event. While SOFA consistently records postdropout flux enhancements, GPS dosimeters detect equatorial postdropout enhancements in 1.6-3.2 MeV electron fluxes in only 15 of 26 events and all are either concurrent (1 event) with or follow (14 events) the geosynchronous increases of electrons with similar values of the first adiabatic invariant, mu similar to 2.1 x 10(3) MeV G(-1). In addition, 10 of 15 GPS growth periods produced electron enhancements above predropout levels. For all 26 events the phase space density for electrons of similar mu is consistently greater at geosynchronous altitude than at GPS equatorial altitude. The critical factor leading to GPS L = 4.2 electron flux enhancements is elevated geomagnetic activity levels Of Kp similar to 3.0 - 3.5 and above Tor extended periods. A combination of enhanced solar wind ram pressure, electric field (with B-south), and velocity also appears to be necessary. If outward phase space density gradients are combined with the large electric fields generally accompanying elevated Kp, then sufficient conditions may exist to promote the inward radial diffusive transport of equatorial electrons that ultimately lead to electron flux enhancements at GPS altitudes. Comparison of observed and theoretically estimated electron growth rates is consistent with this picture of inward radial transport for these equatorially mirroring particles with mu similar to 2.1 x 10(3) MeV G(-1) at L = 4.2. C1 USAF, Res Lab, VSBS, Space Vehicles Directorate, Hanscom AFB, MA 01731 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Hilmer, RV (reprint author), USAF, Res Lab, VSBS, Space Vehicles Directorate, 29 Randolph Rd, Hanscom AFB, MA 01731 USA. NR 39 TC 43 Z9 43 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-SPACE JI J. Geophys. Res-Space Phys. PD OCT 1 PY 2000 VL 105 IS A10 BP 23311 EP 23322 DI 10.1029/1999JA000380 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 359UN UT WOS:000089630600029 ER PT J AU Amundson, J Schmidt, C Tung, WK Wang, XN AF Amundson, J Schmidt, C Tung, WK Wang, XN TI Charm production in deep inelastic scattering from threshold to high Q(2) SO JOURNAL OF HIGH ENERGY PHYSICS LA English DT Article DE heavy quarks physics; QCD; deep inelastic scattering ID HEAVY-QUARK PRODUCTION; PARTON DISTRIBUTIONS; NEUTRAL-CURRENT; O(ALPHA-S) CORRECTIONS; PERTURBATION-THEORY; INTRINSIC CHARM; GLOBAL ANALYSIS; HERA-DATA; ELECTROPRODUCTION; QCD AB Charm final states in deep inelastic scattering constitute similar to 25% of the inclusive cross-section at small x as measured at HERA. These data can reveal important information on the charm and gluon structure of the nucleon if they are interpreted in a consistent perturbative QCD framework which is valid over the entire energy range from threshold to the high energy limit. We describe in detail how this can be carried out order-by-order in PQCD in the generalized (MS) over bar formalism of Collins (generally known as the ACOT approach), and demonstrate the inherent smooth transition from the 3-flavor to the 4-flavor scheme in a complete order alpha (s) calculation, using a Monte Carlo implementation of this formalism. This calculation is accurate to the same order as the conventional NLO F-2 calculation in the limit Q/m(c) much greater than 1. It includes the resummed large logarithm contributions of the 3-flavor scheme (generally known in this context as the fixed-flavor-number or FFN scheme) to all orders of alpha (s) 1n(m(c)(2)/Q(2)). For the inclusive structure function, comparison with recent HERA data and the existing FFN calculation reveals that the relatively simple order-alpha (s) (NLO) 4-flavor (m(c) not equal = 0) calculation can, in practice, be extended to rather low energy scales, yielding good agreement with data over the full measured Q(2) range. The Monte Carlo implementation also allows the calculation of differential distributions with relevant kinematic cuts. Comparisons with available HERA data show qualitative agreement; however, they also indicate the need to extend the calculation to the next order to obtain better description of the differential distributions. C1 Michigan State Univ, E Lansing, MI 48824 USA. RP Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. EM amundson@fnal.gov; schmidt@pa.msu.edu; tung@pa.msu.edu; wangx@eis.comm.mot.com NR 47 TC 25 Z9 25 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1029-8479 J9 J HIGH ENERGY PHYS JI J. High Energy Phys. PD OCT PY 2000 IS 10 AR 031 PG 35 WC Physics, Particles & Fields SC Physics GA 423EA UT WOS:000168161400031 ER PT J AU Song, J Wesely, ML Coulter, RL Brandes, EA AF Song, J Wesely, ML Coulter, RL Brandes, EA TI Estimating watershed evapotranspiration with PASS. Part I: Inferring root-zone moisture conditions using satellite data SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID EFFECTIVE ROUGHNESS LENGTH; LAND-SURFACE-TEMPERATURE; SOIL-WATER; VEGETATION INDEX; MODEL; RADIATION; FLUXES; EVAPORATION; CONTEXT; ENERGY AB A model framework for parameterized subgrid-scale surface fluxes (PASS) has been modified and applied as PASS1 to use satellite data, models, and limited surface observations to infer root-zone available moisture (RAM) content with high spatial resolution over large terrestrial areas. Data collected during the 1997 Cooperative Atmosphere-Surface Exchange Study field campaign at the Atmospheric Boundary Layer Experiments site in the Walnut River watershed in Kansas were used to evaluate applications of the PASS1 approach to infer soil moisture content at times of satellite overpasses during cloudless conditions. Data from Advanced Very High Resolution Radiometers on the NOAA-14 satellite were collected and then adjusted for atmospheric effects by using LOWTRAN7 and local atmospheric profile data from radiosondes. The input variables for PASS1 consisted of normalized difference vegetation index and surface radiant temperature, together with representative observations of downwelling solar irradiance, air temperature, relative humidity, and wind speed. Surface parameters, including roughness length, albedo, surface conductance for water vapor, and the ratio of soil heat flux to net radiation, were estimated with parameterizations suitable for the area using satellite data and land-use information; pixel-specific near-surface meteorological conditions such as air temperature, vapor pressure, and wind speed were adjusted according to local surface forcing; and RAM content was estimated using surface energy balance and aerodynamic methods. Comparisons with radar cumulative precipitation observations and in situ soil moisture estimates indicated that the spatial and temporal variations of RAM at the times of satellite overpasses were simulated reasonably well by PASS1. C1 No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Natl Ctr Atmospher Res, Res Applicat Program, Boulder, CO 80307 USA. RP Song, J (reprint author), No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. NR 49 TC 20 Z9 20 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD OCT PY 2000 VL 1 IS 5 BP 447 EP 461 DI 10.1175/1525-7541(2000)001<0447:EWEWPP>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 378TX UT WOS:000165601400005 ER PT J AU Song, J Wesely, ML LeMone, MA Grossman, RL AF Song, J Wesely, ML LeMone, MA Grossman, RL TI Estimating watershed evapotranspiration with PASS. Part II: Moisture budgets during drydown periods SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID SURFACE-ENERGY BALANCE; REMOTELY-SENSED DATA; SEMIARID RANGELAND; VEGETATION INDEX; SOIL-MOISTURE; LAND SURFACES; FLUXES; TEMPERATURE; EVAPORATION; RADIATION AB The second part of the parameterization of subgrid-scale surface fluxes model (PASS2) has been developed to estimate long-term evapotranspiration rates over extended areas at a high spatial resolution by using satellite remote sensing data and limited, but continuous, surface meteorological measurements. Other required inputs include data on initial root-zone available moisture (RAM) content computed by PASS1 for each pixel at the time of clear-sky satellite overpasses, normalized difference vegetation index (NDVI) from the overpasses, and databases on available water capacity and land-use classes. Site-specific PASS2 parameterizations evaluate surface albedo, roughness length, and ground heat flux for each pixel, and special functions distribute areally representative observations of wind speed, temperature, and water vapor pressure to individual pixels. The surface temperature for each pixel and each time increment is computed with an approximation involving the surface energy budget, and the evapotranspiration rates are computed via a bulk aerodynamic formulation. Results from PASS2 were compared with observations made during the 1997 Cooperative Atmosphere-Surface Exchange Study field campaign in Kansas. The modeled diurnal variation of RAM content, latent heat flux, and daily evapotranspiration rate were realistic in comparison to measurements at eight surface sites. With the limited resolution of the NDVI data, however, model results deviated from the observations at locations where the measurement sites were in fields with surface vegetative conditions notably different than surrounding fields. Comparisons with aircraft-based flux measurements suggested that the evapotranspiration rates over distances of tens of kilometers were modeled without significant bias. C1 No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Natl Ctr Atmospher Res, Mesoscale & Microscale Meteorol Div, Boulder, CO 80307 USA. Univ Colorado, Program Atmospher & Ocean Studies, Boulder, CO 80309 USA. RP Song, J (reprint author), No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. NR 22 TC 12 Z9 12 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD OCT PY 2000 VL 1 IS 5 BP 462 EP 473 DI 10.1175/1525-7541(2000)001<0462:EWEWPP>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 378TX UT WOS:000165601400006 ER PT J AU Fukumura, R Araki, R Fujimori, A Tsutsumi, Y Kurimasa, A Li, GC Chen, DJ Tatsumi, K Abe, M AF Fukumura, R Araki, R Fujimori, A Tsutsumi, Y Kurimasa, A Li, GC Chen, DJ Tatsumi, K Abe, M TI Signal joint formation is also impaired in DNA-dependent protein kinase catalytic subunit knockout cells SO JOURNAL OF IMMUNOLOGY LA English DT Article ID COMBINED IMMUNE-DEFICIENCY; STRAND BREAK REPAIR; SEVERE COMBINED IMMUNODEFICIENCY; V(D)J RECOMBINATION; CODING JOINT; SCID MOUSE; IONIZING-RADIATION; GENE REARRANGEMENT; NONSENSE MUTATION; MICE AB The effort to elucidate the mechanism of V(D)J recombination has given rise to a dispute as to whether DNA-dependent protein kinase catalytic subunit (DNA-PKcs) contributes to signal joint formation (sjf). Observations reported to date are confusing. Analyses using DNA-PKcs-deficient cells could not conclude the requirement of DNA-PKcs for sjf, because sjf can be formed by end-joining activities which are diverse among cells other than those participating in V(D)J recombination. Here, we observed V(D)J recombination in DNA-PKcs knockout cells and showed that both signal and coding joint formation were clearly impaired in the cells. Subsequently, to directly demonstrate the requirement of DWA-PKcs for sjf, we introduced full-length cDNA of DNA-PKcs into the knockout cells. Furthermore, several mutant DNA-PKcs cDNA constructs designed from mutant cell lines (irs20, V3, murine scid, and SX9) were also introduced into the cells to obtain further evidence indicating the involvement of DNA-PKcs in sjf, We found as a result that the full-length cDNA complemented the aberrant sjf and that the mutant cDNAs constructs also partially complemented it. Lastly, we looked at whether the kinase activity of DNA-PKcs is necessary for sjf and, as a result, demonstrated a close relationship between them. Our observations clearly indicate that the DNA-PKcs controls not only coding joint formation but also the sjf in V(D)J recombination through its kinase activity. C1 Natl Inst Radiol Sci, Div Biol & Oncol, Inage Ku, Chiba 2638555, Japan. Chiba Univ, Grad Sch Sci & Technol, Chiba 260, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Mem Sloan Kettering Canc Ctr, New York, NY 10021 USA. RP Abe, M (reprint author), Natl Inst Radiol Sci, Div Biol & Oncol, Inage Ku, 4-9-1 Anagawa, Chiba 2638555, Japan. NR 40 TC 23 Z9 23 U1 0 U2 0 PU AMER ASSOC IMMUNOLOGISTS PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-1767 J9 J IMMUNOL JI J. Immunol. PD OCT 1 PY 2000 VL 165 IS 7 BP 3883 EP 3889 PG 7 WC Immunology SC Immunology GA 357AZ UT WOS:000089477500044 PM 11034395 ER PT J AU Washington, G Redmond, JM AF Washington, G Redmond, JM TI Special Issue on the 1999 Adaptive Structures and Material Systems Symposium - Preface SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Editorial Material C1 Ohio State Univ, Columbus, OH 43210 USA. Sandia Natl Labs, Livermore, CA 94550 USA. RP Washington, G (reprint author), Ohio State Univ, Columbus, OH 43210 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD OCT PY 2000 VL 11 IS 10 BP 743 EP 743 DI 10.1106/F6KM-X4WA-PAPV-MXEU PG 1 WC Materials Science, Multidisciplinary SC Materials Science GA 545DJ UT WOS:000175200700001 ER PT J AU Martin, JW Redmond, JM Barney, PS Henson, TD Wehlburg, JC Main, JA AF Martin, JW Redmond, JM Barney, PS Henson, TD Wehlburg, JC Main, JA TI Distributed sensing and shape control of piezoelectric bimorph mirrors SO JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES LA English DT Article ID HETERODYNE AB Meeting the long term needs of the remote sensing community requires the development of large aperture space-based optical systems to achieve dramatic improvement', in resolution and sensitivity. It is possible that ultralarge apertures will be obtained using deployable thin film mirror technology, yet many technological barriers must be overcome to make this approach viable. This paper summarizes an initial research effort into the development of piezoelectric thin film mirrors that can be actively shaped using electric fields applied by an electron flux at selected locations. Recent progress is described in the key areas of mirror figure sensing methods, electron gun excitation. and shape control algorithm development. C1 Sandia Natl Labs, Struct Dynam Res Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Remote Sensing & Exploitat Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Control Subsyst Dept, Albuquerque, NM 87185 USA. Univ Kentucky, Dept Mech Engn, Lexington, KY 40506 USA. RP Redmond, JM (reprint author), Sandia Natl Labs, Struct Dynam Res Dept, MS 0847,POB 5800, Albuquerque, NM 87185 USA. NR 27 TC 20 Z9 20 U1 0 U2 1 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 1045-389X J9 J INTEL MAT SYST STR JI J. Intell. Mater. Syst. Struct. PD OCT PY 2000 VL 11 IS 10 BP 744 EP 757 DI 10.1106/2ULX-MNQH-Y1AF-8B5V PG 14 WC Materials Science, Multidisciplinary SC Materials Science GA 545DJ UT WOS:000175200700002 ER PT J AU Savina, M Xu, ZY Wang, Y Reed, C Pellin, M AF Savina, M Xu, ZY Wang, Y Reed, C Pellin, M TI Efficiency of concrete removal with a pulsed Nd : YAG laser SO JOURNAL OF LASER APPLICATIONS LA English DT Article DE laser ablation; concrete; cement; decontamination AB The mechanism and efficiency of ablating concrete surfaces with a pulsed Nd:YAG laser were studied. Ablation efficiency and material removal rates were determined as functions of irradiance and pulse overlap. The ablation mechanism was dominated by fragmentation and disaggregation of the concrete. The ablation efficiency was insensitive to peak laser irradiance over a range from 0.2 to 4.4 MW/cm(2). Excessive pulse overlap (>60%) caused a significant decrease in ablation efficiency by inducing melting. In concrete samples, the cement phase of the material responds in various ways to the laser energy, including disaggregation, melting, and vaporization, but the aggregate portion (sand and rock) mostly fragments. The ablation effluent therefore consists of both micron-size aerosol particles and chunks of fragmented aggregate material. (C) 2000 Laser Institute of America. [S1042-346X(00)00305-3]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Technol Dev Div, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat & Chem Sci, Argonne, IL 60439 USA. RP Savina, M (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Pellin, Michael/B-5897-2008 OI Pellin, Michael/0000-0002-8149-9768 NR 7 TC 6 Z9 6 U1 0 U2 0 PU LASER INST AMER PI ORLANDO PA 13501 INGENUITY DR, SUITE 128, ORLANDO, FL 32826 USA SN 1042-346X J9 J LASER APPL JI J. Laser Appl. PD OCT PY 2000 VL 12 IS 5 BP 200 EP 204 PG 5 WC Materials Science, Multidisciplinary; Optics; Physics, Applied SC Materials Science; Optics; Physics GA 364YL UT WOS:000089921600006 ER PT J AU Tribble, DL Krauss, RM Chu, BM Gong, EL Kullgen, BR Nagy, JO La Belle, M AF Tribble, DL Krauss, RM Chu, BM Gong, EL Kullgen, BR Nagy, JO La Belle, M TI Increased low density lipoprotein degradation in aorta of irradiated mice is inhibited by preenrichment of low density lipoprotein with alpha-tocopherol SO JOURNAL OF LIPID RESEARCH LA English DT Article DE ionizing radiation; lipoproteins; oxidation; antioxidants; atherosclerosis ID CHOLESTEROL-FED RABBITS; ATHEROSCLEROTIC LESIONS; IONIZING-RADIATION; OXIDATION; LDL; INVIVO; SITES; ANTIOXIDANTS; ACCUMULATION; INITIATION AB We previously reported that upper thoracic exposure to ionizing radiation (IR) accelerates fatty streak formation in C57BL/6 mice and that such effects are inhibited by overexpression of the antioxidant enzyme CuZn-superoxide dismutase (SOD), Notably, ZR-accelerated lesion formation is strictly dependent on a high fat diet (i.e., atherogenic lipoproteins) but does not involve alterations in circulating lipid or lipoprotein levels. We thus proposed that LR promotes changes in the artery wall that enhance the deposition of lipoprotein lipids. To address this hypothesis, we examined the effects of IR on aortic accumulation and degradation of low density lipoproteins (LDL). Ten-week-old C57BL/6 mice were exposed to a single (8-Gy) dose of Co-60 radiation to the upper thoracic area or were sham irradiated (controls) and were then placed on the high fat diet. Five days postexposure, the mice received either I-125-labeled LDL (I-125-LDL) (which was used to measure intact LDL) or I-125-labeled tyramine cellobiose (I-125-TC)-LDL (which was used to measure both intact and cell-degraded LDL) via tail vein injection. On the basis of trichloroacetic acid (TCA)-precipitable counts in retroorbital blood samples, greater than or equal to 95% of donor LDL was cleared within 24 h and there were no differences in time-averaged plasma concentrations of the two forms of LDL among irradiated and control mice. Aortic values increased markedly within the first hour and thereafter exhibited a slow increase up to 24 h. There were no differences between irradiated and control mice at 1 h, when values primarily reflected LDL entry, but a divergence was observed thereafter. At 24 h, I-125-TC-associated counts were 1.8-fold higher in irradiated mice (P = 0.10). In contrast, I-125-LDI-associated counts were 30% lower in irradiated mice (P < 0.05), suggesting that most of the retained I-125-TC was associated with LDL degradation products. Consistent with the proposed involvement of oxidative or redox-regulated events, IR-induced LDL degradation was lower in SOD-transgenic than wild-type mice (P < 0.05). The importance of LDL oxidation was suggested by observations that IR-induced LDL degradation was significantly reduced by preenriching LDL with alpha-tocopherol. On the basis of these results, we propose that IR elicits SOD-inhibitable changes in the artery wall that enhance LDL oxidation and degradation leading to the deposition of LDL-borne lipids. These studies provide additional support for the role of oxidation in lipoprotein lipid deposition and atherogenesis and suggest that IR promotes an arterial environment that stimulates this process in vivo. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mol & Nucl Med, Div Life Sci, Berkeley, CA 94720 USA. RP Tribble, DL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Mol & Nucl Med, Div Life Sci, Berkeley, CA 94720 USA. FU NHLBI NIH HHS [R03 HL60533-01, P01 HL18574] NR 30 TC 9 Z9 9 U1 0 U2 0 PU LIPID RESEARCH INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0022-2275 J9 J LIPID RES JI J. Lipid Res. PD OCT PY 2000 VL 41 IS 10 BP 1666 EP 1672 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 360KX UT WOS:000089667800015 PM 11013309 ER PT J AU Yang, JP McAteer, K Silks, LA Wu, RL Isern, NG Unkefer, CJ Kennedy, MA AF Yang, JP McAteer, K Silks, LA Wu, RL Isern, NG Unkefer, CJ Kennedy, MA TI A comprehensive approach for accurate measurement of proton-proton coupling constants in the sugar ring of DNA SO JOURNAL OF MAGNETIC RESONANCE LA English DT Article DE coupling constants; DNA; J doubling; selective deuteration; Stripe-COSY ID E-COSY; NMR; DECONVOLUTION; RELAXATION AB Stereo-selective deuteration has been explored as an approach for improving the accuracy of NMR-derived, three-bond vicinal proton-proton coupling constants in the 12-base-pair DNA Dickerson sequence [d(CGCGAATTCGCG)(2)]. The coupling constants are useful for DNA structure determination in restrained molecular dynamics calculations. Specifically, the A5 and A6 residues were prepared with the H2 " proton stereo-selectively replaced with a deuteron, Deuteration of the H2 " leads to a 42-fold reduction in the transverse cross-relaxation rate of the H2' spin, effectively negating the contribution of transverse cross relaxation to the cross peak frequencies and phases. Calculated linewidth and polarization transfer functions indicated that the reduced dipolar interaction is also expected to result in a significant increase in intensity for all cross peaks involving the H1', H2', or H3' spin. The spectral complexity is also reduced by selective deuteration. Time-shared homonuclear decoupling of passive spins during acquisition was implemented, reducing the spin system, in some cases, to an effectively isolated two-spin system. This enables the use of a 90 degrees mixing pulse instead of the 35 degrees pulse commonly used in standard P.E.COSY experiments, leading to an additional 75% increase in signal intensity, Selective excitation pulses mere used to reduce the number of increments required in the indirect dimension by as much as a factor of 4. The cumulative improvement in sensitivity is striking, approaching three orders of magnitude per unit time. Separate experiments, referred to as Stripe-COSY and Superstripe-COSY, were optimized for each coupling constant measured. Finally, J-doubling was used to obtain the most accurate peak separations. This comprehensive approach shows promise as an effective method for extracting highly accurate homonuclear vicinal coupling constants in DNA. (C) 2000 Academic Press. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Los Alamos Natl Lab, Natl Stable Isotopes Lab, Los Alamos, NM 87545 USA. RP Kennedy, MA (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RI Isern, Nancy/J-8016-2013; OI Isern, Nancy/0000-0001-9571-8864 FU NCRR NIH HHS [RR02231] NR 18 TC 8 Z9 8 U1 1 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1090-7807 J9 J MAGN RESON JI J. Magn. Reson. PD OCT PY 2000 VL 146 IS 2 BP 260 EP 276 DI 10.1006/jmre.2000.2154 PG 17 WC Biochemical Research Methods; Physics, Atomic, Molecular & Chemical; Spectroscopy SC Biochemistry & Molecular Biology; Physics; Spectroscopy GA 361FD UT WOS:000089711600003 PM 11001842 ER PT J AU Stampfer, MR Yaswen, P AF Stampfer, MR Yaswen, P TI Culture models of human mammary epithelial cell transformation SO JOURNAL OF MAMMARY GLAND BIOLOGY AND NEOPLASIA LA English DT Article DE immortality; senescence; conversion; telomerase; TGF beta ID HUMAN BREAST-CANCER; GROWTH-FACTOR-BETA; CARCINOMA IN-SITU; TELOMERASE ACTIVITY; P53 GENE; MALIGNANT TRANSFORMATION; HUMAN FIBROBLASTS; MOUSE TELOMERASE; DEFINED MEDIUM; LINE HMT-3522 AB Human pre-malignant breast diseases, particularly ductal carcinoma in situ (DCIS)(3) already display several of the aberrant phenotypes found in primary breast cancers, including chromosomal abnormalities, telomerase activity, inactivation of the p53 gene, and overexpression of some oncogenes. Efforts to model early breast carcinogenesis in human cell cultures have largely involved studies of in vitro transformation of normal finite lifespan human mammary epithelial cells (HMEC) to immortality and malignancy. We present a model of HMEC immortal transformation consistent with the known in vivo data. This model includes a recently described, presumably epigenetic process, termed conversion, which occurs in cells that have overcome stringent replicative senescence and are thus able to maintain proliferation with critically short telomeres. The conversion process involves reactivation of telomerase activity, and acquisition of good uniform growth in the absence and presence of TGF beta. We propose that overcoming the proliferative constraints set by senescence, and undergoing conversion, represent key rate-limiting steps in human breast carcinogenesis, and occur during early stage breast cancer progression. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Stampfer, MR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,70A-1118, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA-24844] NR 74 TC 34 Z9 34 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1083-3021 J9 J MAMMARY GLAND BIOL JI J. Mammary Gland Biol. Neoplasia PD OCT PY 2000 VL 5 IS 4 BP 365 EP 378 DI 10.1023/A:1009525827514 PG 14 WC Oncology; Endocrinology & Metabolism; Physiology SC Oncology; Endocrinology & Metabolism; Physiology GA 407FZ UT WOS:000167262700004 PM 14973382 ER PT J AU Lambrakos, SG Milewski, JO AF Lambrakos, SG Milewski, JO TI A multiscale homogenization procedure for analysis of processes involving heat deposition using constrained parameter optimization SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE heat deposition; multiscale homogenization; parameter optimization; temperature histories; weld analysis ID GEOMETRIC CONSTRAINTS; PENETRATION AB We present aspects of a general procedure to be used in conjunction with constrained parameter optimization for the analysis of processes involving heat deposition such as welding processes and those involving rapid prototyping by means of powder deposition. Our emphasis in this report is on the construction of generating functions and subdomain elliptic solvers useful for the practical application of constrained parameter optimization for the calculation of thermal histories. The procedure for constructing generating functions and elliptic solvers is based on the concept of multiscale homogenization. We discuss those elements of the theoretical foundation of the general methodology based on constrained parameter optimization as these elements relate to the application of generating functions and subdomain solvers. In addition, we present a prototype weld analysis, which serves to demonstrate many of the details associated with the application of this methodology. C1 USN, Res Lab, Div Mat Sci & Technol, Washington, DC 20375 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Met Grp, Los Alamos, NM 87545 USA. RP Lambrakos, SG (reprint author), USN, Res Lab, Div Mat Sci & Technol, Washington, DC 20375 USA. NR 11 TC 0 Z9 0 U1 1 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD OCT PY 2000 VL 9 IS 5 BP 562 EP 570 DI 10.1361/105994900770345700 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA 370RH UT WOS:000165135700013 ER PT J AU Berger, A Pang, AW Hopster, H AF Berger, A Pang, AW Hopster, H TI Studies of hysteresis loop criticality in ultrathin Gd(0001)/W(110)-films SO JOURNAL OF MATERIALS PROCESSING & MANUFACTURING SCIENCE LA English DT Article; Proceedings Paper CT International Workshop on Hysteresis, Metastabilitiy and Aftereffect CY AUG 28-30, 2000 CL CHICAGO, ILLINOIS ID MAGNETIC REORIENTATION TRANSITION; SELF-ORGANIZED CRITICALITY; FERROMAGNETIC DOMAIN-WALL; EPITAXIAL GD-FILMS; BARKHAUSEN NOISE; CURIE-TEMPERATURE; GD(0001) SURFACE; AVALANCHES; GADOLINIUM; DYNAMICS AB We report an experimental study on the disorder dependence of hysteresis loop behavior for ultrathin epitaxial Gd-films. The use of ultrathin films with in-plane orientation of the magnetization allows the suppression of dipolar effects and enables us to mimic theoretical models of collective magnetization reversal. The sample disorder is tuned by varying the annealing temperature in the range of T-anneal = 470 K-870 K after room temperature deposition of Gd(0001)/W(110)-films. In accordance with theoretical predictions, we find two regimes for the magnetization reversal: (a) for large disorder, the magnetization changes gradually, i.e., the reversal processes of individual sample parts are uncorrelated and (b) for small disorder, the magnetization reversal is jump-like, i.e., major parts of the sample switch collectively. The transition between these two regimes is abrupt, which confirms the theoretically predicted existence of a critical point in the non-equilibrium phase diagram. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Natl Chang Hua Univ Educ, Dept Phys, Changhua 50058, Taiwan. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. RI Berger, Andreas/D-3706-2015 OI Berger, Andreas/0000-0001-5865-6609 NR 52 TC 3 Z9 3 U1 0 U2 2 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 1062-0656 J9 J MATER PROCESS MANU JI J. Mater. Process. Manuf. Sci. PD OCT PY 2000 VL 9 IS 2 BP 131 EP 142 DI 10.1106/0WM3-J7BM-77XB-AJMB PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 530PG UT WOS:000174367700006 ER PT J AU McGraw, JM Perkins, JD Hasoon, F Parilla, PA Warmsingh, C Ginley, DS Mateeva, E Readey, DW AF McGraw, JM Perkins, JD Hasoon, F Parilla, PA Warmsingh, C Ginley, DS Mateeva, E Readey, DW TI Pulsed laser deposition of oriented V2O5-thin films SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID THIN-FILMS; VANADIUM-PENTOXIDE; LITHIUM BATTERIES; OPTICAL-PROPERTIES; V2O5; ELECTRODES; INTERCALATION; XEROGELS; GROWTH; DEINTERCALATION AB We have found that by varying only the substrate temperature and oxygen pressure five different crystallographic orientations of V2O5 thin films can be grown, ranging from amorphous to highly textured crystalline. Dense, phase-pure V2O5 thin films were grown on SnO2/glass substrates and amorphous quartz substrates by pulsed laser deposition over a wide range of temperatures and oxygen pressures. The films' microstructure, crystallinity, and texturing were characterized by electron microscopy, x-ray diffraction, and Raman spectroscopy. Temperature and oxygen pressure appeared to play more significant roles in the resulting crystallographic texture than did the choice of substrate. A growth map summarizes the results and delineates the temperature and O-2 pressure window for growing dense, uniform, phase-pure V2O5 films. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Colorado Sch Mines, Golden, CO 80401 USA. RP McGraw, JM (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 28 TC 16 Z9 17 U1 0 U2 8 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD OCT PY 2000 VL 15 IS 10 BP 2249 EP 2265 DI 10.1557/JMR.2000.0323 PG 17 WC Materials Science, Multidisciplinary SC Materials Science GA 360PM UT WOS:000089676500030 ER PT J AU Paddison, SJ Bender, G Kreuer, KD Nicoloso, N Zawodzinski, TA AF Paddison, SJ Bender, G Kreuer, KD Nicoloso, N Zawodzinski, TA TI The microwave region of the dielectric spectrum of hydrated Nafion (R) and other sulfonated membranes SO JOURNAL OF NEW MATERIALS FOR ELECTROCHEMICAL SYSTEMS LA English DT Article DE dielectric constant; conductivity; Nafion (R); PEEK; microwave spectral region; water transport and mechanism ID ION-EXCHANGE MEMBRANES; CONTAINING PERFLUOROSULFONATE IONOMERS; PRESSURE ELECTRICAL-CONDUCTIVITY; ANGLE X-RAY; POLYMER ELECTROLYTES; ELECTROOSMOTIC DRAG; WATER-CONTENT; TRANSPORT; RELAXATION; ACID AB The microwave region (0.045-30 GHz) of the dielectric spectrum is reported here for Nafion(R) 105, 117, and 120 and for PEEK L540, G530, and a blend of PEEK with 5% PES at various levels of hydration. Our measurements have shown a strong dependence of the dielectric constant and loss factor of the Nafion(R) membranes with water content, The dielectric constant varied from as high as 30 at I GHz in the wettest samples (where up 13 water molecules were associated with each sulfonate group) to only 7, in samples with just 4 waters/SO(3)(-) at similar frequencies. In contrast, the PEEK membranes displayed a much weaker dependence in the dielectric response with hydration. Amongst the tested PEEK membranes, the G530 samples exhibited the highest dielectric constant of nearly 20 at 1 GHz for samples possessing 12 water molecules per fixed site. At similar water contents, the L540 and PEEK + 5% PES membranes exhibited a dielectric constant of only 10. These results suggest that the water molecules are more tightly bound to the sulfonate groups in the PEEK membranes than in the Nafion(R) membranes. Finally, the conductivity of the membranes at various water contents and at frequencies from 1-7 GHz was extracted from the loss factor spectra. When these high frequency conductivities were compared at similar water contents, all of the Nafion(R) membranes displayed considerably higher values than the PEEK membranes. C1 Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Stuttgart, Inst Phys Elekt, D-7000 Stuttgart, Germany. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. RP Paddison, SJ (reprint author), Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. EM s.paddison@motorola.com RI Paddison, Stephen/B-2935-2014 NR 45 TC 42 Z9 42 U1 0 U2 11 PU ECOLE POLYTECHNIQUE MONTREAL PI MONTREAL PA C P 6079, SUCC CENTRE-VILLE, MONTREAL, PQ H3C 3A7, CANADA SN 1480-2422 J9 J NEW MAT ELECTR SYS JI J. New Mat.Electrochem. Syst. PD OCT PY 2000 VL 3 IS 4 BP 291 EP 300 PG 10 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 355WE UT WOS:000089410900003 ER PT J AU DeMint, AL Leckey, JH AF DeMint, AL Leckey, JH TI Effect of silicon impurities and heat treatment on uranium hydriding rates SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID KINETICS AB Several experiments were run to identify variables that affect the hydriding rate of depleted uranium. Only two factors affecting hydriding rate were found: temperature (and time) of the final heat treatment, and silicon content. Increasing the time and temperature of alpha-phase anneals increased the reaction rate, and annealing in the beta-phase greatly increased the reaction rate over alpha-phase annealing. Silicon contents of up to 100 wppm cause dramatic increases in the hydride reaction rate for both alpha- and beta-phase annealed samples. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Dev Div, Oak Ridge, TN 37831 USA. RP DeMint, AL (reprint author), Dev Div, Oak Ridge Y-12 Plant,POB 2009,MS 8096, Oak Ridge, TN 37831 USA. NR 8 TC 17 Z9 18 U1 3 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 2000 VL 281 IS 2-3 BP 208 EP 212 DI 10.1016/S0022-3115(00)00238-5 PG 5 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 360NJ UT WOS:000089673900014 ER PT J AU Giacobbe, MJ Lam, NQ Rehn, LE Baldo, PM Funk, L Stubbins, JF AF Giacobbe, MJ Lam, NQ Rehn, LE Baldo, PM Funk, L Stubbins, JF TI Heavy-ion cascade effects on radiation-induced segregation kinetics in Cu-1%Au alloys SO JOURNAL OF NUCLEAR MATERIALS LA English DT Article ID DISPLACEMENT CASCADES; MOLECULAR-DYNAMICS; SOLUTE SEGREGATION; IRRADIATION; METALS; REMNANTS AB Various dual ion irradiations were conducted to investigate the effect of heavy-ion cascades on the fluxes of freely migrating defects which drive radiation-induced segregation (RIS) in Cu-1at.%Au alloys. In situ Rutherford backscattering spectroscopy (RBS) was used to measure the RIS suppression effect of heavy-ion bombardment (with 300-keV Al+, 800-keV Cu+, and 1.2-MeV Ag+) on 1.5-MeV He+-RIS of Au in the near-surface region of the alloy during concurrent He+ and heavy-ion irradiations at 400 degrees C. Results demonstrated that the suppression of He+-RIS correlated well with the cascade volume produced by concurrent Al+, Cu+, and Ag+ irradiation per second and was independent of the weighted average primary recoil energy. Model calculations of the kinetics of RIS during dual beam irradiation were also performed and compared with the measurements. Information regarding the energetics of freely migrating point defects and their relative production efficiencies was obtained from systematic fitting. Using the values previously reported for the energies of formation and migration for vacancies and interstitials in Cu, the binding and migration energies of Au-interstitial and Au-vacancy complexes in the alloy were found to be -0.14, 0.15, and 0.03 and 0.76 eV, respectively. The respective derived efficiencies of freely migrating defect production by energetic He+, Al+, Cu+, and Ag+ ions were 0.25, 0.12, 0.09, and 0.08. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Illinois, Dept Nucl Engn, Urbana, IL 61801 USA. RP Lam, NQ (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 25 TC 1 Z9 1 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3115 J9 J NUCL MATER JI J. Nucl. Mater. PD OCT PY 2000 VL 281 IS 2-3 BP 213 EP 224 DI 10.1016/S0022-3115(00)00330-5 PG 12 WC Materials Science, Multidisciplinary; Nuclear Science & Technology SC Materials Science; Nuclear Science & Technology GA 360NJ UT WOS:000089673900015 ER PT J AU Gerasimov, MR Franceschi, M Volkow, ND Gifford, A Gatley, SJ Marsteller, D Molina, PE Dewey, SL AF Gerasimov, MR Franceschi, M Volkow, ND Gifford, A Gatley, SJ Marsteller, D Molina, PE Dewey, SL TI Comparison between intraperitoneal and oral methylphenidate administration: A microdialysis and locomotor activity study SO JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS LA English DT Article ID DEFICIT HYPERACTIVITY DISORDER; INTRAVENOUS METHYLPHENIDATE; THREO-METHYLPHENIDATE; NUCLEUS-ACCUMBENS; HUMAN BRAIN; DOPAMINE; COCAINE; CHILDREN; RAT; PHARMACOKINETICS AB The therapeutic and stimulant properties of methylphenidate (MP), a drug commonly prescribed for the treatment of attention deficit hyperactivity disorder, have been attributed to increases in synaptic dopamine (DA) concentrations resulting from the blockade of DA transporters. In addition to obvious difficulties inherent in any interspecies comparison, interpretation of preclinical studies done with MP is further complicated by different routes of administration in animals (i.v. and i.p.) compared with humans (oral). In the present study we compared the effects of i.p. and intragastric (oral) MP both on rat nucleus accumbens DA assessed by in vivo microdialysis and on locomotor activity measured in a photocell apparatus. We also compared regional brain uptake and plasma levels of [H-3]MP after administration of 5 mg/kg via both routes. Intraperitoneal MP (5 and 10 mg/kg) was approximately twice as potent as intragastric MP in terms of increasing extracellular DA levels and in stimulating locomotion. This was consistent with the higher brain uptake of [H-3]MP when given i.p. rather than intragastrically. The dose of 2 mg/kg produced significant increases in both measurements when administered i.p., but not intragastrically. This study shows that relatively low doses of MP (2 mg i.p. and 5 mg intragastric) significantly increase extracellular DA and locomotor activity and indicates that the differences in the neurochemical and behavioral effects of MP between the intragastric and the i.p. routes are due to central drug bioavailability. 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 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, MH R2955155] NR 36 TC 165 Z9 167 U1 1 U2 6 PU AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0022-3565 J9 J PHARMACOL EXP THER JI J. Pharmacol. Exp. Ther. PD OCT PY 2000 VL 295 IS 1 BP 51 EP 57 PG 7 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA 354AA UT WOS:000089306600008 PM 10991960 ER PT J AU Vreeland, V Kloareg, B AF Vreeland, V Kloareg, B TI Cell wall biology in red algae: Divide and conquer SO JOURNAL OF PHYCOLOGY LA English DT Editorial Material ID PORPHYRA-PURPUREA RHODOPHYTA; VAR TAMBALANG RHODOPHYTA; KAPPA-CARRAGEENASE; ALTEROMONAS-CARRAGEENOVORA; LOCALIZATION; PROTEIN; CYCLE C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. CNRS, UMR 1931, Stn Biol Roscoff, F-29682 Roscoff, France. Labs Goemar, UMR 1931, Stn Biol Roscoff, F-29682 Roscoff, France. RP Vreeland, V (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, MS 66,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 27 TC 12 Z9 12 U1 2 U2 7 PU PHYCOLOGICAL SOC AMER INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044 USA SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD OCT PY 2000 VL 36 IS 5 BP 793 EP 797 DI 10.1046/j.1529-8817.2000.03651-2.x PG 5 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 375NY UT WOS:000165409200002 ER PT J AU Cao, Z Lee, BI Samuels, WD Exarhos, GJ AF Cao, Z Lee, BI Samuels, WD Exarhos, GJ TI Thermal behavior of sol-gel derived phosphate ceramics SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE ceramics; sol-gel growth; thermal expansion ID CRYSTALLIZATION; GLASSES AB A series of phosphosilicate and phosphotitanate ceramics with different compositions was prepared through sol-gel process. The phase evolution was studied using X-ray diffractometry. P:Si gels remain amorphous up to the compositions of P : Si = 0.4: 1 mole ratio, and begin to crystallize to Si5O(PO4)(6) at higher phosphorus contents. The sintering property examined by push-rod dilatometer technique showed that P:Si gels can be densified at 400 degrees C. Weight loss and phase transition of samples upon firing was investigated using thermogravimetric analysis and differential thermal analysis. Linear percentage thermal expansion of P:Si and P:Ti crystal phase was observed and briefly discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Clemson Univ, Dept Ceram & Mat Engn, Clemson, SC 29634 USA. Battelle Pacific NW Natl Lab, Richland, WA 99352 USA. RP Lee, BI (reprint author), Clemson Univ, Dept Ceram & Mat Engn, Clemson, SC 29634 USA. NR 31 TC 4 Z9 5 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD OCT PY 2000 VL 61 IS 10 BP 1677 EP 1685 DI 10.1016/S0022-3697(00)00028-7 PG 9 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 338GZ UT WOS:000088411900016 ER PT J AU Smith, AB AF Smith, AB TI Fast-neutron interaction with isotopic and elemental molybdenum SO JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS LA English DT Article ID OPTICAL-MODEL; ELASTIC-SCATTERING; INELASTIC-SCATTERING; ENERGY-DEPENDENCE; FINITE NUCLEI; STATE AB Results of elemental neutron-scattering measurements at incident energies of 4.5-10 MeV are presented. A comprehensive interpretation of the fast-neutron interaction with elemental and isotopic molybdenum at energies of less than or equal to 30 MeV is outlined. Spherical, vibrational and dispersive models are considered, including isospin, energy-dependent and mass effects. Existing dichotomies in the literature are alleviated. The models are vehicles for fundamental physical investigations and the provision of data for applied purposes. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ Arizona, Tucson, AZ 85721 USA. RP Smith, AB (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 67 TC 8 Z9 8 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0954-3899 J9 J PHYS G NUCL PARTIC JI J. Phys. G-Nucl. Part. Phys. PD OCT PY 2000 VL 26 IS 10 BP 1467 EP 1488 DI 10.1088/0954-3899/26/10/303 PG 22 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 368LF UT WOS:000090117900003 ER PT J AU Rateitschak, K Klages, R Hoover, WG AF Rateitschak, K Klages, R Hoover, WG TI The Nose-Hoover thermostated Lorentz gas SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article; Proceedings Paper CT NATO Advanced Research Workshop on Nonlinear Science - Dynamics and Stochasticity CY JUN 30-JUL 03, 1999 CL BRUSSELS, BELGIUM SP NATO, Belgian Fed Off Sci Tech & Cultural Affairs, European Commiss, Fond Nat Rech Sci, Fonds Wetenschappelijk Onderzoek, ULB DE nonequilibrium steady states; chaotic transport; Nose-Hoover thermostat; multifractal attractor; periodic Lorentz gas ID EQUILIBRIUM MOLECULAR-DYNAMICS; NONEQUILIBRIUM STEADY-STATES; CANONICAL ENSEMBLE; DETERMINISTIC SCATTERING; LYAPUNOV EXPONENTS; SHEAR-FLOW; BEHAVIOR; SYSTEMS AB We apply the Nose-Hoover thermostat and three variations of it, which control different combinations of velocity moments, to the periodic Lorentz gas. Switching on an external electric field leads to nonequilibrium steady states for the four models. By performing computer simulations we study the probability density, the conductivity and the attractor in nonequilibrium. The results are compared to the Gaussian thermostated Lorentz gas and to the Lorentz gas as thermostated by deterministic scattering. We find that slight modifications of the Nose-Hoover thermostat lead to different dynamical properties of our models. However, in all cases the attractor appears to be multifractal. C1 Free Univ Brussels, Ctr Nonlinear Phenomena & Complex Syst, B-1050 Brussels, Belgium. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94551 USA. Lawrence Livermore Natl Lab, Methods Dev Grp, Livermore, CA 94551 USA. RP Rateitschak, K (reprint author), Free Univ Brussels, Ctr Nonlinear Phenomena & Complex Syst, Campus Plaine CP 231,Blvd Triomphe, B-1050 Brussels, Belgium. RI Klages, Rainer/B-7194-2008 OI Klages, Rainer/0000-0003-3811-3070 NR 39 TC 20 Z9 20 U1 2 U2 6 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD OCT PY 2000 VL 101 IS 1-2 BP 61 EP 77 DI 10.1023/A:1026447620778 PG 17 WC Physics, Mathematical SC Physics GA 384RF UT WOS:000165958100005 ER PT J AU Chu, CW Xue, YY Wang, YS Heilman, AK Lorenz, B Meng, RL Cmaidalka, J Dezaneti, LM AF Chu, CW Xue, YY Wang, YS Heilman, AK Lorenz, B Meng, RL Cmaidalka, J Dezaneti, LM TI The unusual phase-transitions in ruthenate-cuprate superconducting ferromagnets SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE phase transitions; ruthenate-cuprate; superconducting ferromagnets ID SPONTANEOUS VORTEX PHASE; GD; EU AB We have systematically investigated the magnetic, electrical, and structural properties of the high-purity superconducting ferromagnet RuSr2GdCu2Os8 in which superconductivity and significant ferromagnetism have been reported to coexist. Our results show that there may exist in this compound a novel superconducting state which is characterized by the absence of a bulk Meissner effect, the presence of negligible superconducting condensation energy, and the appearance of an unusually large effective penetration depth. Such a state appears to have a nonuniform filamentary structure existing in the less magnetic walls between the ferromagnetic domains or a fine-grain structure beset by ferromagnetic walls between antiferromagnetic "domains," similar to the case of NdNi2B2C. These results are presented and contrasted with the recently reported Meissner effect in RuSr2GdCu2O8 in terms of the various phase transition sequences predicted. C1 Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. Univ Houston, Dept Phys, Houston, TX 77204 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Chu, CW (reprint author), Univ Houston, Texas Ctr Superconduct, Houston, TX 77204 USA. NR 26 TC 12 Z9 12 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 679 EP 686 DI 10.1023/A:1007837409178 PG 8 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900003 ER PT J AU Greene, LH Aprili, M Covington, M Badica, E Pugel, DE Aubin, H Xia, YM Salamon, MB Jain, S Hinks, DG AF Greene, LH Aprili, M Covington, M Badica, E Pugel, DE Aubin, H Xia, YM Salamon, MB Jain, S Hinks, DG TI Andreev bound-state tunneling and ESR spectroscopy of high-temperature superconductors and observations of broken time-reversal symmetry SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE Andreev bound state; tunneling spectroscopy; electron paramagnetic resonance spectroscopy; broken time-reversal symmetry; YBCO; BSCCO ID D-WAVE SUPERCONDUCTORS; YBA2CU3O7 THIN-FILMS; T-C SUPERCONDUCTORS; SURFACE-STATES; VORTEX-CORE; JUNCTIONS; CONDUCTANCE; DEPENDENCE; GAP AB An emphasis on reliable materials growth and development of new fabrication techniques has allowed us to investigate the electronic structure of high-temperature superconductors by planar quasiparticle tunneling and electron paramagnetic resonance (EPR) spectroscopies. The quasiparticle (QP) density of states (DoS) is investigated by tunneling into oriented thin films of Y1Ba2Cu3O7 (YBCO) and single crystals of Ba2Sr2Ca1Cu2O8 (BSCCO). Data are obtained as a function of crystallographic orientation, temperature, doping, damage, and applied magnetic field. These data demonstrate that the observed zero-bias conductance peak (ZBCP) is composed of Andreev bound states (ABS) which intrinsically form at a symmetry-breaking interface of an unconventional superconductor, for example, a (110)surface of d-wave YBCO. Tunneling into doped or ion-damaged YBCO provides a measure of the QP scattering rate below T-c. An applied field causes Doppler shift of the ABS, arising from the scalar product between the QP velocity and the superfluid momentum, v(F).P-s, observed as a splitting in the ZBCP. Magnetic hysteresis of the splitting is consistent with the effects of strong vortex pinning near the interface. The directional field dependence shows that the ABS is highly anisotropic in its transport. These results, plus in-plane crystallographic orientational dependence on single-crystal BSCCO, demonstrate the d-wave symmetry of this superconductor. Below similar to 8 K and in zero applied field, the ZBCP splits, indicating a transition into a superconducting state with spontaneously broken time-reversal symmetry (BTRS). EPR experiments are used to detect directly the spontaneous formation of the magnetic moments in the BTRS state. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Greene, LH (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. NR 58 TC 1 Z9 1 U1 0 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 703 EP 708 DI 10.1023/A:1007897727833 PG 6 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900008 ER PT J AU Haase, J Slichter, CP Stern, R Milling, CT Hinks, DG AF Haase, J Slichter, CP Stern, R Milling, CT Hinks, DG TI NMR evidence for spatial modulations in the cuprates SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE nuclear magnetic resonance; spatial modulations; cuprates ID T-J MODEL; NEUTRON-SCATTERING; LA2-XSRXCUO4; LA1.85SR0.15CUO4; SUPERCONDUCTORS AB Nuclear magnetic resonance (NMR) data on Cu, apical and planar O in La1.85Sr0.15CuO4 are presented. Spin echo double resonance shows that the large Cu magnetic shift distribution is of short-length scale. Analysis of the O data reveals static modulations of the spin susceptibility with a spin-spin correlation function near zero. The Cu shift distribution is found to be of orbital origin. The full planar oxygen spectra show a correlated modulation of the electric field gradient with the spin susceptibility. Similar results on other cuprates indicate universality of these phenomena. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. Univ Stuttgart, Inst Phys 2, D-70569 Stuttgart, Germany. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Slichter, CP (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Stern, Raivo/A-5387-2008 OI Stern, Raivo/0000-0002-6724-9834 NR 17 TC 22 Z9 22 U1 1 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 723 EP 726 DI 10.1023/A:1007853912812 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900011 ER PT J AU Crabtree, GW Kwok, WK Olsson, RJ Karapetrov, G Paulius, LM Petrean, A Tobos, V Moulton, WG AF Crabtree, GW Kwok, WK Olsson, RJ Karapetrov, G Paulius, LM Petrean, A Tobos, V Moulton, WG TI Disordered vortex phases in YBa2Cu3O7-delta SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE disordered vortex phases; YBa2Cu3O7-delta ID HIGH-TEMPERATURE SUPERCONDUCTORS; BOSON LOCALIZATION; TRANSITIONS; LATTICE AB The disordered vortex phases induced by line and point pinning in YBa2Cu3O7-delta are explored. At high defect densities, only a single disordered solid separated from the liquid phase by a melting line is observed. At low defect densities the topology of the phase diagram changes dramatically, with a vortex lattice phase adjoining disordered phases at high or low field. Critical points at the termination of the first-order melting line separate the lattice and the disordered phases. The line defect disordered phases follow the expected Bose glass behavior, while the point defect disordered phases do not exhibit the expected vortex glass behavior. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Western Michigan Univ, Kalamazoo, MI 49008 USA. Florida State Univ, Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. RP Crabtree, GW (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Karapetrov, Goran/C-2840-2008 OI Karapetrov, Goran/0000-0003-1113-0137 NR 27 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 741 EP 748 DI 10.1023/A:1007862114629 PG 8 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900015 ER PT J AU Kresin, V Ovchinnikov, Y Wolf, S AF Kresin, V Ovchinnikov, Y Wolf, S TI Intrinsic inhomogeneity of the cuprates: Pseudogap, resistive vs. diamagnetic transitions SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE cuprates; inhomogeneity; pseudogap ID T-C; NORMAL-STATE; SUPERCONDUCTORS; BI2SR2CACU2O8+DELTA; TL2BA2CUO6+DELTA AB The pseudogap phenomenon in the cuprates can be explained by an intrinsic inhomogeneity of the samples. At temperatures above the superconducting resistive transition but below the temperature at which the pseudogap disappears, the sample contains superconducting islands embedded in a normal matrix. As a result, the normal resistance coexists with the gap structure, and there is a splitting of the resistive and Meissner traditions. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. LD Landau Theoret Phys Inst, Moscow 11733V, Russia. USN, Res Lab, Washington, DC 20375 USA. RP Kresin, V (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 19 TC 1 Z9 1 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 777 EP 780 DI 10.1023/A:1007834803243 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900022 ER PT J AU Smith, JL Clark, RG Cooley, JC Gay, EC Hamilton, AR Hults, WL Hanrahan, RJ Lumpkin, NE McPheeters, CC Mielke, CH O'Brien, JL Schmiedeshoff, GM Thoma, DJ AF Smith, JL Clark, RG Cooley, JC Gay, EC Hamilton, AR Hults, WL Hanrahan, RJ Lumpkin, NE McPheeters, CC Mielke, CH O'Brien, JL Schmiedeshoff, GM Thoma, DJ TI Uranium superconductivity redux SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE uranium; resistivity; single crystal ID FERROMAGNETIC METALS; KONDO-LATTICE AB Since the discovery of heavy-fermion superconductivity in uranium compounds in the early 1980s, other uranium compounds have been discovered that are fully as interesting to study. However, as we look forward in the year 2000, we now have higher-purity, single crystals of the element itself. Preliminary resistivity and ac susceptibility measurements show the improved quality of the samples and thus hold the promise of understanding many aspects of its superconductivity, which have remained untouched for almost 25 years. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ New S Wales, Ctr Quantum Comp Technol, Sydney, NSW 2052, Australia. Argonne Natl Lab, CMT Div, Argonne, IL 60439 USA. Occidental Coll, Dept Phys, Los Angeles, CA 90041 USA. RP Smith, JL (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RI O'Brien, Jeremy/A-6290-2008; Hamilton, Alex/A-5639-2011; Cooley, Jason/E-4163-2013; Mielke, Charles/S-6827-2016; OI Hamilton, Alex/0000-0001-7484-3738; Mielke, Charles/0000-0002-2096-5411; O'Brien, Jeremy/0000-0002-3576-8285 NR 13 TC 4 Z9 4 U1 0 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 833 EP 835 DI 10.1023/A:1007811625533 PG 3 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900033 ER PT J AU Schmiedeshoff, GM De Boer, C Tompkins, MV Beyermann, WP Lacerda, AH Smith, JL Canfield, PC AF Schmiedeshoff, GM De Boer, C Tompkins, MV Beyermann, WP Lacerda, AH Smith, JL Canfield, PC TI Superconductivity (and magnetism) in the nickel borocarbides SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT International Conference on Major Trends in Superconductivity in the New Millennium CY MAR 31-APR 06, 2000 CL KLOSTERS, SWITZERLAND DE magnetism; nickel borocarbides ID UPPER CRITICAL-FIELD; LATTICE MELTING TRANSITIONS; YNI2B2C SINGLE-CRYSTAL; ELECTRONIC-STRUCTURE; WEAK FERROMAGNETISM; BORIDE CARBIDES; HEAVY-FERMION; VORTEX-GLASS; D-WAVE; LUNI2B2C AB An overview of superconductivity in the rare-earth nickel borocarbides (RNi2B2C, where R represents a rare earth element or Y) is presented, with an emphasis on the interplay between magnetism and superconductivity in general and the behavior of the nonmagnetic superconductors YNi2B2C and LuNi2B2C, in particular. Some open questions are identified. C1 Occidental Coll, Dept Phys, Los Angeles, CA 90041 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Univ Calif Los Alamos Natl Lab, Pulse Facil, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Schmiedeshoff, GM (reprint author), Occidental Coll, Dept Phys, Los Angeles, CA 90041 USA. RI Canfield, Paul/H-2698-2014 NR 49 TC 7 Z9 7 U1 1 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD OCT PY 2000 VL 13 IS 5 BP 847 EP 853 DI 10.1023/A:1007815726441 PG 7 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 376LK UT WOS:000165458900035 ER PT J AU Hiller, RA Swift, GW AF Hiller, RA Swift, GW TI Condensation in a steady-flow thermoacoustic refrigerator SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID ENGINES AB Condensation may occur in an open-flow thermoacoustic cooler with stack temperatures below the saturation temperature of the flowing gas. In the experimental device described here the flowing gas, which is also the acoustic medium, is humid air, so the device acts as a flow-through dehumidifier. The humid air stream flows through an acoustic resonator. Sound energy generated by electrodynamic drivers produces a high-amplitude standing wave inside of the resonator, which causes cooling on a thermoacoustic stack. Condensation of water occurs as the humid air passes through the stack and is cooled below its dew point, with the condensate appearing on the walls of the stack. The dry, cool air passes out of the resonator, while the condensate is wicked away from the end of the stack. Thermoacoustic heat pumping is strongly affected by the form of the condensate inside of the stack, whether condensed mostly on the stack plates, or largely in the form of droplets in the gas stream. Two simple models of the effect of the condensate are matched to a measured stack temperature profile; the results suggest that the thermoacoustic effect of droplets inside the stack is small. (C) 2000 Acoustical Society of America. [S0001-4966(00)02210-4]. C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Hiller, RA (reprint author), Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. NR 16 TC 7 Z9 7 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD OCT PY 2000 VL 108 IS 4 BP 1521 EP 1527 DI 10.1121/1.1289664 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 364LW UT WOS:000089894700016 PM 11051479 ER PT J AU Thayer, RL Schmidt, SR Dorris, SE Bullard, JW Lanagan, MT AF Thayer, RL Schmidt, SR Dorris, SE Bullard, JW Lanagan, MT TI Reactive sintering and retrograde densification of bulk bismuth-based superconductors SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CRITICAL-CURRENT DENSITY; SHEATHED TAPE; MICROSTRUCTURE; PHASE; TEMPERATURE; (BI; BI2SR2CACU2O8; CERAMICS; KINETICS; WIRES AB Densification was observed when bulk ceramic superconductors with a composition of Bi1.8Pb0.4Sr2Ca2Cu3O10+delta were sintered for short times (<4 h) near the incongruent melting temperature. The initial shrinkage of the powder compacts was correlated with the existence of a transient liquid phase. Retrograde densification, which is a decrease in density, occurred for longer sintering times and was attributed to changes in pore structure. The results provide direction for future processing of bulk bismuth-based superconductors and powder-in-tube tapes for the fabrication of long-length wire. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. RP Thayer, RL (reprint author), Penn State Univ, Mat Res Lab, University Pk, PA 16802 USA. NR 24 TC 4 Z9 4 U1 1 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 2000 VL 83 IS 10 BP 2365 EP 2368 PG 4 WC Materials Science, Ceramics SC Materials Science GA 363KG UT WOS:000089834400003 ER PT J AU Morissette, SL Lewis, JA Cesarano, J Dimos, DB Baer, TY AF Morissette, SL Lewis, JA Cesarano, J Dimos, DB Baer, TY TI Solid freeform fabrication of aqueous alumina-poly(vinyl alcohol) gelcasting suspensions SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CERAMICS; MODEL AB Solid freeform fabrication of aqueous alumina-poly(vinyl alcohol) (Al2O3-PVA) gel-casting suspensions was conducted using a computer-controlled extrusion apparatus fitted with a two-nozzle delivery system. The impact of casting parameters on the shear rate profiles experienced during deposition was evaluated via conventional flow analysis and computer simulations. In addition, the influence of these parameters on line resolution/uniformity, printability, and as-cast component properties was studied using laser profilometry, optical microscopy, and scanning electron microscopy. Continuous printablity was achieved for tip diameters ranging from 0.254 to 1.370 mm for all mixing rates and suspension compositions studied. Printed lines were uniform with good edge definition, and line dimensions were independent of mixing rate for these process conditions. The Al2O3 volume fraction (phi(Al2O3)) in the as-deposited layers depended on casting conditions and crosslinking agent concentration, where (phi(Al2O3) increased with decreased tip diameter and increased cross-linking agent concentration. The free-formed Al2O3 components exhibited uniform particle packing, with minimal macrodefects (e.g., slumping or staircasing) and no discernable microdefects (e.g., bubbles or cracking). C1 Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Sandia Natl Labs, Direct Fabricat Dept, Albuquerque, NM 87185 USA. RP Morissette, SL (reprint author), MIT, Ctr Mat Proc, Cambridge, MA 02139 USA. NR 43 TC 47 Z9 53 U1 2 U2 32 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 2000 VL 83 IS 10 BP 2409 EP 2416 PG 8 WC Materials Science, Ceramics SC Materials Science GA 363KG UT WOS:000089834400010 ER PT J AU Kitayama, M Narushima, T Carter, WC Cannon, RM Glaeser, AM AF Kitayama, M Narushima, T Carter, WC Cannon, RM Glaeser, AM TI The Wulff shape of alumina: I. Modeling the kinetics of morphological evolution SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID PERIODIC SURFACE PROFILES; ION-IMPLANTED SAPPHIRE; CRACK-LIKE FLAWS; EQUILIBRIUM SHAPE; VICINAL SURFACES; FREE-ENERGY; DIFFUSION; TEMPERATURE; ANISOTROPY; CRYSTAL AB The rate at which fully facetted nonequilibrium shaped particles and pores approach their equilibrium (Wulff) shape via surface diffusion was modeled, and calculations relevant to alumina were performed to guide experimental studies. The modeling focuses on 2-D features, and considers initial particle/pore shape, size, surface energy anisotropy, and temperature (surface diffusivity) as variables. The chemical potential differences driving the shape change are expressed in terms of facet-to-facet differences in weighted mean curvature, Two approaches to modeling the surface flux are taken. One linearizes the difference in the mean chemical potential of adjacent facets, and assumes the flux is proportional to this difference. The other approach treats the surface chemical potential as a continuous function of position, and relates the displacement rate of the surface to the divergence of the surface flux. When consistent values for the relevant materials parameters are used, the predictions of these two modeling approaches agree to within a factor of 1.5, As expected, the most important parameters affecting the evolution times are the cross-sectional area (volume in 3-D) and the temperature through its effect on the surface diffusivity, Pores of micrometer size are predicted to reach near-equilibrium shapes in reasonable times at temperatures as low as 1600 degrees C. The detailed geometry of the initial nonequilibrium shape and the Wulff shape appear to have relatively minor effects on the times required to reach a near-equilibrium shape. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RP Kitayama, M (reprint author), Fukuoka Inst Technol, Higashi Ku, 3-30-1 Wajiro Higashi, Fukuoka 8110295, Japan. RI Carter, W/K-2406-2012 NR 54 TC 21 Z9 21 U1 5 U2 14 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 2000 VL 83 IS 10 BP 2561 EP 2571 PG 11 WC Materials Science, Ceramics SC Materials Science GA 363KG UT WOS:000089834400032 ER PT J AU Kitayama, M Narushima, T Glaeser, AM AF Kitayama, M Narushima, T Glaeser, AM TI The Wulff shape of alumina: II. Experimental measurements of pore shape evolution rates SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID ION-IMPLANTED SAPPHIRE; CRACK-LIKE FLAWS; SURFACE; DIFFUSION; INTERFACES; DECAY AB The rate at which a facetted tetragonal cavity of nonequilibrium shape approaches a cubic equilibrium (Wulff) shape via surface diffusion was modeled. The shape relaxation rate of a facetted "stretched cylinder" was also modeled, For the first geometry, only an approximate solution based on linearizing the mean potential difference between the source and sink facets was obtained. For the stretched cylinder, both an approximate and an exact solution can be obtained; the approximate solution underestimates the evolution rate by a factor of approximate to 2, To assess the applicability of the models, nonequilibrium shape pores of identical initial geometry (approximate to 20 mu m x 20 mu m x 0.5 mu m) were introduced into (0001), {10 (1) over bar 2}, {11 (2) over bar 0}, and {10 (1) over bar 0} surfaces of sapphire single crystals using microfabrication techniques, ion-beam etching, and hot pressing. The large (approximate to 20 pm x 20 mu m) faces of the pore are low-index surfaces whose nature is dictated by the wafer orientation. A series of anneals was performed at 1900 degrees C, and the approach of the pore shape to an equilibrium shape was monitored, The kinetics of shape evolution are highly sensitive to the crystallographic orientation and stability of the low-index surface that dominates the initial pore shape. The measured variations of the pore aspect ratio were compared to those predicted by the kinetic model. The observations suggest that when the initial bounding surface is unstable, shape relaxation may be controlled by diffusion. However, surface-attachment-limited kinetics (SALK) appears to play a major role in determining the pore shape evolution rate in cases where the initial bounding surfaces have orientations that are part of the Wulff shape. C1 Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RP Kitayama, M (reprint author), Fukuoka Inst Technol, Higashi Ku, 3-30-1 Wajiro Higashi, Fukuoka 8110295, Japan. NR 33 TC 31 Z9 31 U1 5 U2 9 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 2000 VL 83 IS 10 BP 2572 EP 2583 PG 12 WC Materials Science, Ceramics SC Materials Science GA 363KG UT WOS:000089834400033 ER PT J AU Brandes, D Wilcox, BP AF Brandes, D Wilcox, BP TI Evapotranspiration and soil moisture dynamics on a semiarid ponderosa pine hillslope SO JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION LA English DT Article DE forest hydrology; semiarid; water balance; evapotranspiration; soil moisture; modeling ID DOUGLAS-FIR STANDS; WATER DEFICITS; NEW-MEXICO; EQUATION; EVAPORATION; ARIZONA; MODEL AB Detailed measurements of soil moisture and ET in semiarid forest environments have not been widely reported in the literature. In this study, soil moisture and water balance components were measured over a four-year period on a semiarid ponderosa pine hillslope, with evapotranspiration (ET) determined as the residual of measured precipitation, runoff, and change in soil moisture storage. ET accounts for approximately 95 percent of the water budget and has a distinctly bimodal annual pattern, with peaks occurring after spring snowmelt and during the late summer monsoon season, periods that coincide with high soil moisture. Weekly growing season ET rates determined by the hillslope water balance are found to be invariably below calculated potential rates. Normalized ET rates are linearly correlated (r(2) = 0.62) with soil moisture; therefore, a simple linear relation is proposed. Growing season soil moisture dynamics were modeled based on this relation. Results are in fair agreement (r(2) = 0.63) with the observed soil moisture data over the four growing seasons; however, for two dry summers with little surface runoff, much better results (r(2) > 0.90) were obtained. C1 Lafayette Coll, Dept Civil & Environm Engn, Easton, PA 18042 USA. Univ Calif Los Alamos Natl Lab, Environm Sci Grp, Los Alamos, NM USA. InterAmer Inst Global Change Res, Sao Paulo, Brazil. RP Brandes, D (reprint author), Lafayette Coll, Dept Civil & Environm Engn, Easton, PA 18042 USA. NR 28 TC 19 Z9 21 U1 0 U2 19 PU AMER WATER RESOURCES ASSOC PI MIDDLEBURG PA 4 WEST FEDERAL ST, PO BOX 1626, MIDDLEBURG, VA 20118-1626 USA SN 1093-474X J9 J AM WATER RESOUR AS JI J. Am. Water Resour. Assoc. PD OCT PY 2000 VL 36 IS 5 BP 965 EP 974 DI 10.1111/j.1752-1688.2000.tb05702.x PG 10 WC Engineering, Environmental; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 366VQ UT WOS:000090027300002 ER PT J AU Schaub, H Akella, MR Junkins, JL AF Schaub, H Akella, MR Junkins, JL TI Adaptive realization of linear closed-loop tracking dynamics in the presence of large system model errors SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article; Proceedings Paper CT AAS/AIAA 9th Space Flight Mechanics Meeting CY FEB 07-10, 1999 CL BRECKENRIDGE, COLORADO SP AAS, Amer Inst Aeronaut & Astronaut ID ATTITUDE DYNAMICS AB A novel adaptive feedback control approach for nonlinear mechanical systems is presented. The approach applies to nonlinear trajectory tracking and has the remarkable property that the tracking error dynamics asymptotically approach a specified linear PID response for the case where the external disturbances are constant. The methodology applies to a large class of nonlinear mechanical systems, however, it is illustrated for the case of nonlinear rigid body maneuvers subject to actuator saturation constraints and large uncertainty of the system mass and inertia properties. While the system mass or inertias are not identified in this approach, the external disturbances are accurately estimated if they are constant or slowly varying with respect to the adaptation rate. A benefit of this method is that it requires no a priori knowledge of the unknown system parameters or bounds thereof. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Texas, Dept Aerosp Engn & Engn Mech, Austin, TX 78712 USA. Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77843 USA. RP Schaub, H (reprint author), Sandia Natl Labs, POB 5800,MS-1003, Albuquerque, NM 87185 USA. NR 16 TC 13 Z9 14 U1 1 U2 1 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD OCT-DEC PY 2000 VL 48 IS 4 BP 537 EP 551 PG 15 WC Engineering, Aerospace SC Engineering GA 456PT UT WOS:000170092000006 ER PT J AU Venugopal, A Macdonald, DD Varma, R AF Venugopal, A Macdonald, DD Varma, R TI Electrochemistry and corrosion of beryllium in buffered and unbuffered chloride solutions SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ALUMINUM-AIR BATTERIES; IMPEDANCE ANALYSIS; AQUEOUS-SOLUTIONS; PASSIVE FILMS; STATE; BEHAVIOR; ANODES AB The electrochemical behavior of Be (99%) in buffered and unbuffered chloride solutions is reported. Anodic oxidation and hydrogen evolution partial currents were delineated by measuring the total current density and the rate of evolution of hydrogen from the metal surface. The partial anodic current density is found to decrease with increasing voltage within the passive range at low voltages, but it tends toward a constant value at high voltages. Beryllium is observed to undergo passivity breakdown in chloride solutions, with the dependencies of the breakdown voltage on chloride concentration and pH being in accordance with the predictions of the point defect model. The barrier layer on beryllium in contact with aqueous solutions is most likely defective BeO, with the principal defects bring oxygen vacancies and/or beryllium interstitials. However, the present data do not discount the possibility that the barrier layer is the hydride, BeHx (x less than or equal to 2). (C) 2000 The Electrochemical Society. S0013-4651(99)04-032-X. All rights reserved. C1 Penn State Univ, Ctr Electrochem Sci & Technol, University Pk, PA 16802 USA. Univ Calif Los Alamos Natl Lab, Dept Met & Mat Sci, Los Alamos, NM 87545 USA. RP Venugopal, A (reprint author), Penn State Univ, Ctr Electrochem Sci & Technol, University Pk, PA 16802 USA. NR 33 TC 7 Z9 7 U1 2 U2 14 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD OCT PY 2000 VL 147 IS 10 BP 3673 EP 3679 DI 10.1149/1.1393957 PG 7 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 359GJ UT WOS:000089602900017 ER PT J AU Dinh, HN Birss, VI AF Dinh, HN Birss, VI TI Effect of substrate on polyaniline film properties - A cyclic voltammetry and impedance study SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID CONDUCTING POLYANILINE; ELECTRODES; ANILINE; GROWTH; DEGRADATION; OXIDATION; TRANSPORT; REDUCTION; BEHAVIOR AB The electrochemical properties of polyaniline (PANI) films, grown using multicycling methods, but using two different upper limits, have been examined in detail at three different substrates [Au, Pr, and glassy carbon (GC)]. Overall, type I films are only weakly dependent on the substrate employed. Even so, impedance measurements have shown that type I PANT films (grown by cycling between 0 and ca. 1 V in 0.1 M aniline + 1 M H2SO4), formed on Pt and Au, exhibit the most rapid growth rate, while the highest film pseudocapacitance per unit charge is seen for Pt substrates. Type I PANT has a porosity of 45-50% when formed on Pt and Au, but the porosity is much higher ten. 77%) on GC, inversely correlated with film growth rate. The substrate has a more pronounced effect on the electrochemical properties of type II PANI films (grown by cycling between 0 and 1.7 V in 0.02 M aniline + 1 M H2SO4 solution). This is because type I films are Formed at potentials at which PANT is conducting, while type II are formed primarily when PANI is insulating. Therefore, type I film growth occurs predominantly at the conducting PANI/solution interface, while growth of type II films occurs primarily at the underlying metal/solution interface, causing the substrate properties to become more significant. The growth rate of type II PANI is most rapid on GC, due to the absence of a barrier oxide film, vs, on Pt and Au. (C) 2000 The Electrochemical Society. S0013-4651(99)11-096-6. All rights reserved. C1 Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada. RP Dinh, HN (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 38 TC 41 Z9 42 U1 5 U2 14 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD OCT PY 2000 VL 147 IS 10 BP 3775 EP 3784 DI 10.1149/1.1393973 PG 10 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 359GJ UT WOS:000089602900033 ER PT J AU Gall, K Horstemeyer, MF Van Schilfgaarde, M Baskes, MI AF Gall, K Horstemeyer, MF Van Schilfgaarde, M Baskes, MI TI Atomistic simulations on the tensile debonding of an aluminum-silicon interface SO JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS LA English DT Article DE fracture; delamination; finite strain; anisotropic material; atomistic simulations ID DYNAMIC CRACK-GROWTH; ZERO CREEP EXPERIMENTS; EMBEDDED-ATOM METHOD; UNIVERSAL FEATURES; FRACTURE PROCESS; VOID NUCLEATION; COMPOSITES; RESISTANCE; METALS; MULTILAYERS AB In this paper we present Modified Embedded Atom Method (MEAM) simulations of the deformation and fracture characteristics of an incoherent interface between purl FCC aluminum and diamond cubic silicon. As a first approximation, the study only considers the normal tensile separation of a [100] interface with the principal crystallographic axis of the aluminum and the silicon aligned, The MEAM results show that the relaxed interface possesses a rippled structure, instead of a planar atomic interface, and such ripples act as local stress concentrators and initiation sites for interfacial failure. The stress-strain (traction-displacement) response of aluminum and silicon blocks attached at an interface depends on the distance from the interface that the boundary conditions are applied, i.e. the size of the atomic blocks, and the location of the measured opening displacement. Point vacancy defects near the interface are found to decrease the maximum normal tensile stress that the interface can support at a rate almost linearly proportional to the number fraction of the dispersed defects. A crack-like Vacancy defect in the bulk aluminum or silicon must reach an area fraction (projected to the surface normal to the tensile axis) of about 50 or 30%, respectively, in order to shift the failure from the interface to the bulk materials, It is further demonstrated that the present results are consistent with continuum-based traction separation laws, provided that the opening displacement is measured near the physical boundary of the deforming cohesive zone (+/-10 Angstrom from the boundary of the Al-Si interface). As the opening displacements are measured farther from the interface, the traction-displacement response approaches that of classical linear elastic fracture mechanics, (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Sandia Natl Labs, Ctr Mat Sci & Engn, Livermore, CA 94550 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Horstemeyer, MF (reprint author), Sandia Natl Labs, Ctr Mat Sci & Engn, MS 9405, Livermore, CA 94550 USA. OI Horstemeyer, Mark/0000-0003-4230-0063 NR 70 TC 97 Z9 104 U1 8 U2 42 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-5096 J9 J MECH PHYS SOLIDS JI J. Mech. Phys. Solids PD OCT PY 2000 VL 48 IS 10 BP 2183 EP 2212 DI 10.1016/S0022-5096(99)00086-1 PG 30 WC Materials Science, Multidisciplinary; Mechanics; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 345QA UT WOS:000088825600008 ER PT J AU Allman, BE McMahon, PJ Tiller, JB Nugent, KA Paganin, D Barty, A McNulty, I Frigo, SP Wang, YX Retsch, CC AF Allman, BE McMahon, PJ Tiller, JB Nugent, KA Paganin, D Barty, A McNulty, I Frigo, SP Wang, YX Retsch, CC TI Noninterferometric quantitative phase imaging with soft x rays SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID SYNCHROTRON-RADIATION; ELECTRON-MICROSCOPY; INTENSITY EQUATION; CONTRAST; RETRIEVAL; TOMOGRAPHY; RESOLUTION; TRANSPORT; COHERENCE; OBJECTS AB We demonstrate quantitative noninterferometric x-ray phase-amplitude measurement. We present results from two experimental geometries. The first geometry uses x rays diverging from a point source to produce high-resolution holograms of submicrometer-sized objects. The measured phase of the projected image agrees with the geometrically determined phase to within +/-7%. The second geometry uses a direct imaging microscope setup that allows the formation of a magnified image with a zone-plate lens. Here a direct measure of the object phase is made and agrees with that of the magnified object to better than +/-10%. In both eases the accuracy of the phase is limited by the pixel resolution. (C) 2000 Optical Society of America [S0740-3232(00)01710-5] OCIS cades: 100.0100, 100.5070, 070.0070, 090.0090, 110.7440, 120.5050, 180.7460. C1 Univ Melbourne, Sch Phys, Melbourne, Vic 3010, Australia. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Allman, BE (reprint author), Univ Melbourne, Sch Phys, Melbourne, Vic 3010, Australia. RI paganin, david/B-9717-2009; Nugent, Keith/J-2699-2012; Barty, Anton/K-5137-2014; Nugent, Keith/I-4154-2016 OI Nugent, Keith/0000-0003-1522-8991; Barty, Anton/0000-0003-4751-2727; Nugent, Keith/0000-0002-4281-3478 NR 44 TC 42 Z9 42 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD OCT PY 2000 VL 17 IS 10 BP 1732 EP 1743 DI 10.1364/JOSAA.17.001732 PG 12 WC Optics SC Optics GA 359HA UT WOS:000089604400005 PM 11028521 ER PT J AU Nishi, M Nakao, H Fujii, Y Masuda, T Uchinokura, K Shirane, G AF Nishi, M Nakao, H Fujii, Y Masuda, T Uchinokura, K Shirane, G TI Critical neutron scattering study of the compositional phase transition in Mg-doped CuGeO3 SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Article DE CuGeO3; spin-Peierls; alternating chains; antiferromagnetism; neutron scattering ID SPIN-PEIERLS TRANSITION; SYSTEMS; CUPRATE; ORDER AB Cu1-xMgxGeO3 undergoes a first-order phase transition at a critical concentration x(c) between an antiferromagnetic (AF) state on dimerized lattice (D-AF) and an AF Neel state on undistorted uniform lattice (U-AF). Previous magnetic susceptibility measurements showed x(c)= 0.023 while a recent neutron scattering study reported x(c) = 0.027 +/- 0.001. The present critical scattering due to antiferromagnetic fluctuations near the superlattice reflection (0, 1, 1/2) unambiguously determines x(c) = 0.028 +/- 0.001 at T-N =3.4 similar to 4K. Also, at T = 1.3K, the phase boundary was determined to be x(c) = 0.028 +/- 0.001 by observation of a jump of an effective magnetic moment across x(c). C1 Univ Tokyo, Inst Solid State Phys, Neutron Scattering Lab, Tokai, Ibaraki, Japan. Univ Tokyo, Dept Adv Mat Sci, Bunkyo Ku, Tokyo 1138656, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Nishi, M (reprint author), Univ Tokyo, Inst Solid State Phys, Neutron Scattering Lab, 106-1 Shirakata, Tokai, Ibaraki, Japan. EM nishi@issp.u-tokyo.ac.jp NR 9 TC 6 Z9 6 U1 0 U2 0 PU PHYSICAL SOC JAPAN PI TOKYO PA YUSHIMA URBAN BUILDING 5F, 2-31-22 YUSHIMA, BUNKYO-KU, TOKYO, 113-0034, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD OCT PY 2000 VL 69 IS 10 BP 3186 EP 3188 DI 10.1143/JPSJ.69.3186 PG 3 WC Physics, Multidisciplinary SC Physics GA 367NN UT WOS:000090068500012 ER PT J AU Armaly, BF Li, A Abu-Mulaweh, HI Chen, TS AF Armaly, BF Li, A Abu-Mulaweh, HI Chen, TS TI Measurements and predictions of turbulent natural convection adjacent to backward-facing step SO JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER LA English DT Article ID HEAT-TRANSFER; FLUID-FLOW; FIELD CALCULATIONS; REATTACHING FLOWS; MODEL AB Measurements and predictions of turbulent natural convection adjacent to a two-dimensional, vertical backward-facing step in airflow are reported. The upstream and downstream waifs of the backward-facing step geometry were maintained at a constant and uniform temperature, while the backward-facing step was kept adiabatic. The experiment was carried out for a backward-facing step height of 22 mm and a temperature difference, between the heated walls and the mainstream, of 30 degreesC. Measurements and predictions of the mean velocities and temperature distributions, along with the distributions of turbulent intensities, turbulent heat fluxes, and Reynolds stress components, are presented at various axial locations downstream of the backward-facing step. A reasonable agreement appears to exist between the measured and the predicted mean quantities, but discrepancies still exist between the measured and the predicted turbulence quantities. C1 Univ Missouri, Dept Mech & Aerosp Engn & Engn Mech, Rolla, MO 65409 USA. RP Armaly, BF (reprint author), US Dept Energy, Div Mat Sci & Engn, Off Basic Energy Sci, SC 31,19901 Germantown Rd, Germantown, MD 20874 USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0887-8722 J9 J THERMOPHYS HEAT TR JI J. Thermophys. Heat Transf. PD OCT-DEC PY 2000 VL 14 IS 4 BP 584 EP 592 DI 10.2514/2.6561 PG 9 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 368XE UT WOS:000090142100017 ER PT J AU Garcia-Lerma, JG Gerrish, PJ Wright, AC Qari, SH Heneine, W AF Garcia-Lerma, JG Gerrish, PJ Wright, AC Qari, SH Heneine, W TI Evidence of a role for the Q151L mutation and the viral background in development of multiple dideoxynucleoside-resistant human immunodeficiency virus type 1 SO JOURNAL OF VIROLOGY LA English DT Article ID POL GENE-MUTATIONS; REVERSE-TRANSCRIPTASE; DRUG-RESISTANCE; REPLICATIVE FITNESS; COMBINATION THERAPY; IN-VITRO; ZIDOVUDINE; INHIBITORS; PROTEASE; SENSITIVITY AB The majority of human immunodeficiency virus type 1 (HIV-1)-infected patients treated with zidovudine (AZT) plus zalcitabine (ddC) and didanosine (ddI) develop AZT resistance mediated by mutations such as T215Y and M41L. Only a small proportion of patients develop multiple dideoxynucleoside resistance (MDNR) mediated by the Q151M mutation. To gain insight into the factors responsible for the low frequency of selection of Q151M, we evaluated the replication capabilities of recombinant viruses carrying two possible intermediates (151L or 151K) of the Q151M mutation generated in different reverse transcriptase (RT) genetic backgrounds. The 151L and 151K mutations were introduced by site-directed mutagenesis in RTs from two patient-derived HIV-1 isolates that had either wild type (WT) Q or the Q151M (posttreatment isolate) mutation. For comparison, both mutations were also introduced in a laboratory-adapted HIV-1 strain (HIV-1(HXB2)). Analysis of replication capabilities showed that both 151L and 151K were lethal in RT genetic backgrounds of the WT isolate and in HIV-1(HXB2). In contrast, 151L but not 151K allowed virus replication in RT backgrounds of the posttreatment isolate. Three mutations (V35I, S68G, and I178M) were present in the RT background of the posttreatment isolate but not in the WT isolate. Introduction of S68G in the RT of both the WT isolate and HIV-1(HXB2) partially restored replication capacity of recombinants carrying the 151L mutation. The S68G mutation alone did not confer a significant replicative disadvantage in WT viruses. Like HIV-1(151M), HIV-1(151L) RT was found to have six- to eightfold resistance to AZT-triphosphate (TP), ddA-TP, and ddC-TP, indicating an MDNR phenotype. However, HIV-1(151L) was found to be less fit than HIV-1(151M), which may explain the preferential selection of HIV-1(151M) observed in vivo. The demonstrated ability of HIV-1(151L/68G) to replicate and the associated MDNR suggest that 151L is a potential intermediate of Q151M. The dependence of HIV-1(151L) on other mutations, such as S68G, for replication may explain the low frequency of the Q151M-mediated pathway of resistance. C1 Ctr Dis Control & Prevent, HIV AIDS & Retrovirol Branch, Div AIDS STD & TB Lab Res, Natl Ctr Infect Dis, Atlanta, GA 30333 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp, Los Alamos, NM USA. RP Heneine, W (reprint author), Ctr Dis Control & Prevent, HIV AIDS & Retrovirol Branch, Div AIDS STD & TB Lab Res, Natl Ctr Infect Dis, 1600 Clifton Rd NE,MS G-19, Atlanta, GA 30333 USA. OI Gerrish, Philip/0000-0001-6393-0553 NR 29 TC 49 Z9 51 U1 0 U2 1 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0022-538X J9 J VIROL JI J. Virol. PD OCT PY 2000 VL 74 IS 20 BP 9339 EP 9346 DI 10.1128/JVI.74.20.9339-9346.2000 PG 8 WC Virology SC Virology GA 357LP UT WOS:000089503400001 PM 11000201 ER PT J AU Gauthier, PJ Le Cloarec, MF Condomines, M AF Gauthier, PJ Le Cloarec, MF Condomines, M TI Degassing processes at Stromboli volcano inferred from short-lived disequilibria (Pb-210-Bi-210-Po-210) in volcanic gases SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE eruptive activity; magma chamber dynamics; magma degassing; radioactive disequilibria; stromboli; volcanic gases ID EXPLOSIVE ACTIVITY; RESIDENCE TIME; MOUNT-ETNA; MAGMA; DYNAMICS; ERUPTION; GROWTH; LAVA; SOLUBILITY; SPECIATION AB Volcanic aerosols and gases released by three active craters at Stromboli volcano have been regularly collected since 1985. In this paper, we present new evidence of the high volatility of some nuclides among radon daughters (Pb-210, Bi-210 and Po-210), which are strongly fractionated, leading to significant radioactive disequilibria in volcanic exhalations. The very low volcanic activity in October 1996 allowed a separate sampling of each crater plume for the first time; remote sampling of the bulk plume were also performed. These data show that the chemical composition of volcanic aerosols remains constant within the first few hundred meters from their source vents, ensuring the validity of remote sampling when the activity does not allow one to approach the active craters. Moreover, it appears that there is no differentiation of gases from one crater to another suggesting that the geometry of the upper plumbing system of the volcano is rather simple. gases being directly emitted from a shallow magma chamber without significant cooling inside the edifice. On the basis of the assumption of a continuously replenished shallow magma reservoir in steady state, we propose a dynamic model of degassing accounting for the variations of radionuclide contents and ratios observed in the gas phase since 1985. This model allows us to relate these variations to changes in the magma chamber dynamics, namely the magma residence time inside the chamber and the escape time of gases from it, both parameters being closely linked to the volcanic activity. While gases are always emitted within a few hours after bubble nucleation, suggesting that the chamber is no deeper than a few hundred meters, magma residence time varies from less than 20 days during eruptive periods (highly explosive or effusive periods) to more than 200 days before the 1985 eruption. The latter figure is explained by the storage at shallow depth of a poorly renewed magma batch that fed the eruption. The variations of the residence time observed over the studied period suggest that the steady-state dynamics of the Stromboli magma chamber is sustained for rather short periods of a few months at most. On basis of the knowledge of the deep undegassed magma supply and the magma residence time, we estimate the volume of the shallow magma chamber at about 7 +/- 2 x 10(5) m(3). The good agreement of our results with previous estimates based on both geochemical and geophysical studies suggests that the measurement of radioactive disequilibria in the gas phase provides a robust tool for a deeper understanding of the volcanic activity and the magma dynamics beneath active volcanoes. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Blaise Pascal, Lab Magmas & Volcans LMV, F-63038 Clermont Ferrand, France. Univ Blaise Pascal, CNRS, OPGC, F-63038 Clermont Ferrand, France. Ctr Rech Volcanol, F-63038 Clermont Ferrand, France. CEA, CNRS, Lab Sci Climat & Environnement, F-91198 Gif Sur Yvette, France. RP Gauthier, PJ (reprint author), Univ Calif Los Alamos Natl Lab, EES-1,Grp MS D462, Los Alamos, NM 87545 USA. NR 46 TC 30 Z9 30 U1 1 U2 6 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 OCT PY 2000 VL 102 IS 1-2 BP 1 EP 19 DI 10.1016/S0377-0273(00)00179-7 PG 19 WC Geosciences, Multidisciplinary SC Geology GA 366YB UT WOS:000090032900001 ER PT J AU Nishioka, T Yao, JL Sakakura, K Epstein, JS AF Nishioka, T Yao, JL Sakakura, K Epstein, JS TI Measurements of near-tip displacement fields, separated J integrals and separated energy release rates for interfacial cracks using phase-shifting Moire interferometry SO JSME INTERNATIONAL JOURNAL SERIES A-SOLID MECHANICS AND MATERIAL ENGINEERING LA English DT Article DE fracture mechanics; adhesive joints; J integral; experimental stress analysis; phase-shifting; Moire interferometry; bimaterial; interface; mixed mode; separated J integral; separated energy release rate AB In this paper, first, the concepts of the separated J integrals and the separated energy release rates, which have the physical significance of the energy release rates from corresponding material sides of a bimaterial are briefly presented. Phase-shifting moire interferometry is used to investigate interfacial crack-tip behavior of a bimaterial specimen, which is fabricated of epoxy and aluminum. The loading angle to the interfacial crack is systematically changed. The inplane displacement fields near the interface crack are recorded by the phase-shifting moire interferometry. Using the measured displacement fields, the stress intensity factors and the separated energy release rates are evaluated. From the theoretical and experimental results, it is found that the compliant material (epoxy) side provides considerably larger fracture energy to the interfacial crack tip. C1 Kobe Univ Mercantile Marine, Dept Ocean Mech Engn, Higashinada Ku, Kobe, Hyogo 6580022, Japan. Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. RP Nishioka, T (reprint author), Kobe Univ Mercantile Marine, Dept Ocean Mech Engn, Higashinada Ku, 5-1-1 Fukae Minamimachi, Kobe, Hyogo 6580022, Japan. NR 22 TC 6 Z9 6 U1 1 U2 1 PU JAPAN SOC MECHANICAL ENGINEERS PI TOKYO PA SHINANOMACHI-RENGAKAN BLDG, SHINANOMACHI 35, SHINJUKU-KU, TOKYO, 160-0016, JAPAN SN 1344-7912 J9 JSME INT J A-SOLID M JI JSME Int. J. Ser. A-Solid Mech. Mat. Eng. PD OCT PY 2000 VL 43 IS 4 BP 334 EP 342 PG 9 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 381UU UT WOS:000165782500007 ER PT J AU Hjelm, RP Wampler, W Gerspacher, M AF Hjelm, RP Wampler, W Gerspacher, M TI The structure of carbon black and its associations in elastomer composites: A study using neutron scattering SO KAUTSCHUK GUMMI KUNSTSTOFFE LA English DT Article DE small-angle neutron scattering; contrast variation; carbon black; graphitic shell; quasirodlike aggregates ID MORPHOLOGY AB We have been exploring the use of small-angle neutron scattering and the method of contrast variation to give a new look at very old problem - reinforcement of elastomers by carbon black in durable rubber products. It was found that in an experimental carbon black, HSA, the aggregates are quasirodlike, containing an average of 4-6 particles. The aggregates have an outer graphitic shell and an inner core of lower density carbon. The core is continuous throughout the carbon black aggregate. Contrast variation of swollen HSA-polyisoprene gels shows that the HSA is completely embedded in polyisoprene. The agglomerates are formed predominantly by end on associations of the rodlike aggregates. The surface structure of the carbon black appears smooth over length scales above about 1 nm. Further studies on production carbon blacks suggest that the shell-like aggregate structure is present in commercial carbon blacks. C1 Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RP Hjelm, RP (reprint author), Univ Calif Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RI Lujan Center, LANL/G-4896-2012 NR 8 TC 4 Z9 4 U1 0 U2 3 PU DR ALFRED HUTHIG VERLAG GMBH PI HEIDELBERG 1 PA POSTFACH 102869, W-69018 HEIDELBERG 1, GERMANY SN 0022-9520 J9 KAUT GUMMI KUNSTST JI Kautsch. Gummi Kunstst. PD OCT PY 2000 VL 53 IS 10 BP 592 EP 595 PG 4 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 363NR UT WOS:000089841900006 ER PT J AU Cerchiai, BL Zumino, B AF Cerchiai, BL Zumino, B TI Properties of perturbative solutions of unilateral matrix equations SO LETTERS IN MATHEMATICAL PHYSICS LA English DT Article DE unilateral matrix equations AB A left-unilateral matrix equation is an algebraic equation of the form a(0)+a(1)x+a(2)x(2)+...+a(n)x(n)=0 where the coefficients a(r) and the unknown x are square matrices of the same order and all coefficients are on the left (similarly for a right-unilateral equation). Recently certain perturbative solutions of unilateral equations and their properties have been discussed. We present a unified approach based on the generalized Bezout theorem for matrix polynomials. Two equations discussed in the literature, their perturbative solutions and the relation between them are described. More abstractly, the coefficients and the unknown can be taken as elements of an associative, but possibly noncommutative, algebra. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Cerchiai, BL (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. OI Cerchiai, Bianca Letizia/0000-0002-0109-0330 NR 5 TC 2 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0377-9017 J9 LETT MATH PHYS JI Lett. Math. Phys. PD OCT PY 2000 VL 54 IS 1 BP 33 EP 42 DI 10.1023/A:1007690508610 PG 10 WC Physics, Mathematical SC Physics GA 408GF UT WOS:000167317600004 ER PT J AU Landis, CS Li, X Telang, FW Coderre, JA Micca, PL Rooney, WD Latour, LL Vetek, G Palyka, I Springer, CS AF Landis, CS Li, X Telang, FW Coderre, JA Micca, PL Rooney, WD Latour, LL Vetek, G Palyka, I Springer, CS TI Determination of the MRI contrast agent concentration time course in vivo following bolus injection: Effect of equilibrium transcytolemmal water exchange SO MAGNETIC RESONANCE IN MEDICINE LA English DT Article DE contrast reagent; concentration; bolus-tracking; transcytolemmal water exchange ID IN-VIVO; EXTRACTION FRACTION; MAGNETIC-RESONANCE; PERFUSION RATE; TUMORS; BRAIN; RESOLUTION; RELAXIVITY; DIFFUSION; KINETICS AB For bolus-tracking studies, it is commonly assumed that CR concentration bears a linear relationship with the measured (usually longitudinal) (H2O)-H-1 relaxation rate constant, R-1* =(T-1*)(-1). This requires that equilibrium transcytolemmal water exchange be in the fast exchange limit (FXL). However, though systems remain in fast exchange, the FXL will not usually obtain. Here, the consequences are considered: 1) the measurement of R-1* itself can be affected, 2) the resultant non-linear [CR]-dependence causes significant error by assuming FXL, 3) the thermodynamic [CR] (based on the space in which CR is actually distributed) can be determined, 4) transcytolemmal water permeability may be estimated, and 5) the pharmacokinetic parameters can be factored. For a 30-sec, 0.17 mmol/kg dose of GdDTPA(2-), the FXL assumption underestimates the [CR] maximum in rat thigh muscle by a factor of almost two. Similar results are obtained for a rat brain GS-SL gliosarcoma tumor model. Magn Reson Med 44:563-574, 2000. published 2000 Wiley-Liss, Inc.(dagger) C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. NINDS, Sect Stroke Diagnost & Therapeut, Bethesda, MD 20892 USA. RP Springer, CS (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. OI Springer, Charles/0000-0002-5966-2135 FU NIGMS NIH HHS [R01 GM32125] NR 39 TC 150 Z9 151 U1 2 U2 6 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0740-3194 J9 MAGNET RESON MED JI Magn. Reson. Med. PD OCT PY 2000 VL 44 IS 4 BP 563 EP 574 DI 10.1002/1522-2594(200010)44:4<563::AID-MRM10>3.0.CO;2-# PG 12 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 360MG UT WOS:000089671300010 PM 11025512 ER PT J AU Wadsworth, J Lesuer, DR AF Wadsworth, J Lesuer, DR TI Ancient and modem laminated composites - from the Great Pyramid of Gizeh to Y2K SO MATERIALS CHARACTERIZATION LA English DT Article; Proceedings Paper CT IMS 1999 Symposium CY OCT 21-NOV 03, 1999 CL CINCINNATI, OH SP IMS DE laminated metal composite; low-carbon layer; high-carbon layer; steel ID ULTRAHIGH CARBON-STEEL; WELDED DAMASCUS STEELS; IMPACT PROPERTIES; MECHANICAL-BEHAVIOR; IRON ARTIFACTS; BRASS; SUPERPLASTICITY AB Laminated metal composites (LMC's) have been cited in antiquity; for example, an iron laminate that may date as far back as 2750 BC was found in the Great Pyramid in Gizeh in1837. A laminated shield containing bronze, tin, and gold layers is described in detail by Horner. Well-known examples of steel laminates. such as an Adze blade, dating to 400 BC can be found in the literature. The Japanese sword is a laminated composite at several different levels and Merovingian blades were composed of laminated steels. Other examples are also available, including composites from China, Thailand, Indonesia, Germany, Britain, Belgium, France, and Persia. The concept of lamination to provide improved properties has also found expression in modem materials. Of particular interest is the development of laminates including high-carbon and low-carbon layers. These materials have unusual properties that are of engineering interest: they an similar to ancient welded Damascus steels. The manufacture of collectable knives, labeled "welded Damascus," has also been a focus of contemporary knife makers. Additionally, in the former Soviet Union, laminated composite designs have been used in engineering applications. Each of the above areas will be briefly reviewed, and some of the metallurgical principles will be described that underlie improvement in properties by lamination. Where appropriate, links are made between these property improvements and those that may have been present in ancient artifacts. (C) 2001 Elsevier Science Inc. All rights reserved. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Wadsworth, J (reprint author), Lawrence Livermore Natl Lab, POB 808,L-001, Livermore, CA 94551 USA. EM wadsworth3@llnl.gov NR 66 TC 52 Z9 54 U1 6 U2 19 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1044-5803 J9 MATER CHARACT JI Mater. Charact. PD OCT-NOV PY 2000 VL 45 IS 4-5 BP 289 EP 313 DI 10.1016/S1044-5803(00)00077-2 PG 25 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 431DY UT WOS:000168617600005 ER PT J AU Wadsworth, J Lesuer, DR AF Wadsworth, J Lesuer, DR TI The knives of Frank J. Richtig as featured in Ripley's Believe It or Not!(R) SO MATERIALS CHARACTERIZATION LA English DT Article; Proceedings Paper CT IMS 1999 Symposium CY OCT 21-NOV 03, 1999 CL CINCINNATI, OHIO SP IMS AB Unusual claims, resulting from "secret" heat treatment methods, surround the toughness and sharpness of the knives manufactured during the 20th century by a cutler named Frank J. Richtig. Richtig became famous because of his dramatic demonstrations of the toughness of his: blades by hammering them through iron and steel objects and then illustrating their subsequent sharpness. Two of Richtig's blades have been examined and their microstructure and mechanical behavior determined. Comparisons with contemporary steels of similar composition, which are themselves related to ancient Damascus steels, have been made. As a result, proposals regarding Richtig's "secret" heat treatments are given. Some comments are made regarding historical methods of testing blades and thereby provide a context regarding the degree of difficulty in mimicking the remarkable toughness and cutting properties described by Richtig. Finally, some observations are made regarding the contemporary specialty knifemaking industry in the U.S. (C) 2001 Elsevier Science Inc. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Wadsworth, J (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 14 TC 5 Z9 5 U1 2 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-5803 J9 MATER CHARACT JI Mater. Charact. PD OCT-NOV PY 2000 VL 45 IS 4-5 BP 315 EP 326 DI 10.1016/S1044-5803(01)00102-4 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Materials Science, Characterization & Testing SC Materials Science; Metallurgy & Metallurgical Engineering GA 431DY UT WOS:000168617600006 ER PT J AU Waters, AM Martz, HE Dolan, KW Horstemeyer, MF Green, RE AF Waters, AM Martz, HE Dolan, KW Horstemeyer, MF Green, RE TI Three dimensional void analysis of AM60B magnesium alloy tensile bars using computed tomography imagery SO MATERIALS EVALUATION LA English DT Article DE computed tomography; nondestructive void characterization; damage evolution; cast magnesium alloy; three dimensional void statistics ID NUCLEATION; FRACTURE; GROWTH AB Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories, California (SNL) are collaborating on the development of new techniques to study damage evolution and growth in notched Bridgman tensile bars subjected to monotonic loading. This paper focuses on analyzing damage evolution as a function of load, using the nondestructive ive testing (NDT) technique of X-ray computed tomography (CT). This project included several AM60B magnesium alloy tensile bars, which were landed to different percentages of their average failure lend, and subsequently scanned using CT. The CT data was analyzed using a three dimensional (3D) technique to quantify different characteristics of void damage progression as a function of load. The void analysis is being used to refine and calibrate Existing material models. C1 Sandia Natl Lab, Livermore, CA 94550 USA. Johns Hopkins Univ, Ctr Nondestruct Evaluat, Baltimore, MD 21218 USA. RP Waters, AM (reprint author), L-333,POB 808, Livermore, CA 94550 USA. OI Horstemeyer, Mark/0000-0003-4230-0063 NR 19 TC 3 Z9 3 U1 0 U2 3 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD OCT PY 2000 VL 58 IS 10 BP 1221 EP 1227 PG 7 WC Materials Science, Characterization & Testing SC Materials Science GA 362FX UT WOS:000089768900005 ER PT J AU Thomson, RC Miller, MK AF Thomson, RC Miller, MK TI Atom probe characterisation of high temperature materials SO MATERIALS SCIENCE AND TECHNOLOGY LA English DT Article; Proceedings Paper CT Conference on Quantitative Microscopy of High Temperature Materials CY NOV 22-24, 1999 CL SHEFFIELD HALLAM UNIV, SHEFFIELD, ENGLAND HO SHEFFIELD HALLAM UNIV ID FIELD-ION MICROSCOPY; LOW-ALLOY STEEL; EUTECTOID STEEL; PRECIPITATION; MARTENSITE; IMPLEMENTATION; MICROANALYSIS; BERYLLIUM AB An atom probe is capable of quantitatively analysing materials at the atomic level. Modern atom probes are derived from the field ion microscope, and are coupled with time-of-flight mass spectrometers, permitting identification of individual atoms, The introduction of position-sensitive detectors enables the reconstruction of a small volume of the sample owing to simultaneous determination of the x, y, and z coordinates and the mass to charge ratios of individual atoms. This paper focuses on the application of atom probe techniques to the microstructural analysis of high temperature materials. Illustrations include carbide precipitation in creep resistant power plant steels and analyses of model and commercial multicomponent nickel based superalloys, It is demonstrated that atom probe field ion microscopy and atom probe tomography are valuable techniques in the development and understanding of technologically important alloys for high temperature service. C1 Loughborough Univ Technol, Inst Polymer Technol & Mat Engn, Loughborough LE11 3TU, Leics, England. Oak Ridge Natl Lab, Div Met & Ceram, Microscopy & Microanalyt Sci Grp, Oak Ridge, TN 37831 USA. RP Loughborough Univ Technol, Inst Polymer Technol & Mat Engn, Loughborough LE11 3TU, Leics, England. RI Thomson, Rachel/B-4217-2011 OI Thomson, Rachel/0000-0002-3681-0107 NR 41 TC 4 Z9 4 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0267-0836 EI 1743-2847 J9 MATER SCI TECH-LOND JI Mater. Sci. Technol. PD OCT PY 2000 VL 16 IS 10 BP 1199 EP 1206 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 368EA UT WOS:000090103700015 ER PT J AU Toloczko, MB Abe, K Hamilton, ML Garner, FA Kurtz, RJ AF Toloczko, MB Abe, K Hamilton, ML Garner, FA Kurtz, RJ TI The effect of test machine compliance on the measured shear punch yield stress as predicted using finite element analysis SO MATERIALS TRANSACTIONS JIM LA English DT Article DE shear punch test; compliance AB In previous research involving the use of shear punch test, it was assumed that the displacement of the punch tip was only slightly different than the crosshead displacement. The present work explores this assumption and its ramifications by simulating the shear punch test with finite element analysis (FEA). The simulations suggest that punch tip displacement is much less than previously assumed. and that for the test frames which have been used, crosshead displacement is over an order of magnitude greater than punch tip displacement. This difference in displacements is thought to be due to test machine;md punch compliance, and a simple elasticity calculation of the compliance of the punch, the test machine, and the specimen gives a result which is in agreement with the FEA simulations. Based on this work, it appears that the material-to-material variation in prior correlations between shear yield strength and uniaxial yield strength is due to a combination of large test machine compliance and material-to-material differences in the work hardening exponent. C1 Tohoku Univ, Dept Quantum Sci & Energy Engn, Sendai, Miyagi 9808579, Japan. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Toloczko, MB (reprint author), Tohoku Univ, Dept Quantum Sci & Energy Engn, Sendai, Miyagi 9808579, Japan. NR 7 TC 1 Z9 1 U1 0 U2 0 PU JAPAN INST METALS PI SENDAI PA AOBA ARAMAKI, SENDAI, 980, JAPAN SN 0916-1821 J9 MATER T JIM JI Mater. Trans. JIM PD OCT PY 2000 VL 41 IS 10 BP 1356 EP 1359 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 383LU UT WOS:000165884800014 ER PT J AU Kyriakidis, P Journel, AG AF Kyriakidis, P Journel, AG TI Geostatistical space-time models: A review (vol 31, pg 651, 1999) SO MATHEMATICAL GEOLOGY LA English DT Correction C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Reg Climate Lab, Div Earth Sci, Berkeley, CA 94720 USA. Stanford Univ, Dept Petr Engn, Stanford, CA 94305 USA. RP Kyriakidis, P (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Reg Climate Lab, Div Earth Sci, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. NR 1 TC 1 Z9 1 U1 2 U2 7 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0882-8121 J9 MATH GEOL JI Math. Geol. PD OCT PY 2000 VL 32 IS 7 BP 893 EP 893 DI 10.1023/A:1007504725396 PG 1 WC Geosciences, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Geology; Mathematics GA 347KE UT WOS:000088927500006 ER PT J AU Mokhtar-Kharroubi, M Protopopescu, V Thevenot, L AF Mokhtar-Kharroubi, M Protopopescu, V Thevenot, L TI On the singular limit of a model transport semigroup SO MATHEMATICAL METHODS IN THE APPLIED SCIENCES LA English DT Article ID DIFFUSION-APPROXIMATION AB We consider the diffusion limit of a model transport equation on the torus or the whole space, as a scaling parameter epsilon (the mean free path), tends to zero. We show that, for arbitrary initial data u(0)(x, upsilon) the solution converges in norm topology for each t > 0, to the solution of a diffusion equation with initial data u(D)(0)(x) = integral u(0)(x, upsilon) d upsilon. The proof relies on Fourier analysis which diagonalizes the transport operator, a Dunford functional calculus and the analysis of the behaviour of the transport spectrum as epsilon tends to zero. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Univ Franche Comte, CNRS UMR 6623, Equipe Math, F-25030 Besancon, France. Oak Ridge Natl Lab, Div Comp Sci & Math, Oak Ridge, TN 37831 USA. RP Mokhtar-Kharroubi, M (reprint author), Univ Franche Comte, CNRS UMR 6623, Equipe Math, 16 Route Gray, F-25030 Besancon, France. NR 20 TC 2 Z9 2 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0170-4214 J9 MATH METHOD APPL SCI JI Math. Meth. Appl. Sci. PD OCT PY 2000 VL 23 IS 15 BP 1301 EP 1322 DI 10.1002/1099-1476(200010)23:15<1301::AID-MMA166>3.0.CO;2-6 PG 22 WC Mathematics, Applied SC Mathematics GA 361LC UT WOS:000089723700002 ER PT J AU Tong, CH Ye, Q AF Tong, CH Ye, Q TI Analysis of the finite precision bi-conjugate gradient algorithm for nonsymmetric linear systems SO MATHEMATICS OF COMPUTATION LA English DT Article DE bi-conjugate gradient algorithm; error analysis; convergence analysis; nonsymmetric linear systems ID LANCZOS-ALGORITHM; ITERATIVE METHODS; ROUNDING ERRORS; CONVERGENCE; BEHAVIOR; MATRIX; CG AB In this paper we analyze the bi-conjugate gradient algorithm in finite precision arithmetic, and suggest reasons for its often observed robustness. By using a tridiagonal structure, which is preserved by the finite precision bi-conjugate gradient iteration, we are able to bound its residual norm by a minimum polynomial of a perturbed matrix (i.e, the residual norm of the exact GMRES applied to a perturbed matrix) multiplied by an amplification factor. This shows that occurrence of near-breakdowns or loss of biorthogonality does not necessarily deter convergence of the residuals provided that the amplification factor remains bounded. Numerical examples are given to gain insights into these bounds. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Univ Manitoba, Dept Math, Winnipeg, MB R3T 2N2, Canada. RP Tong, CH (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. NR 27 TC 8 Z9 8 U1 0 U2 0 PU AMER MATHEMATICAL SOC PI PROVIDENCE PA 201 CHARLES ST, PROVIDENCE, RI 02940-2213 USA SN 0025-5718 J9 MATH COMPUT JI Math. Comput. PD OCT PY 2000 VL 69 IS 232 BP 1559 EP 1575 PG 17 WC Mathematics, Applied SC Mathematics GA 357FM UT WOS:000089487900012 ER PT J AU Walter, PL AF Walter, PL TI Dynamic force, pressure, and acceleration Part 9: Measurement system signal validation SO MEASUREMENTS & CONTROL LA English DT Article AB In addition to the desired signal, the output from a measurement system can contain noise. If this noise contamination is not identified, erroneus data can be accepted as valid. The goal of this part is to enable the reader to incorporate check-channels into their measurement system for signal validation. Once data are validated as noise free, the "rules of thumb" of Part 7 can be applied to assess the adequacy of the dynamic performance of the measurement system. C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Walter, PL (reprint author), Texas Christian Univ, Dept Engn, Ft Worth, TX 76129 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MEASUREMENTS & DATA CORP PI PITTSBURGH PA 2994 W LIBERTY AVE, PITTSBURGH, PA 15216 USA SN 0148-0057 J9 MEAS CONTROL-US JI Meas. Control PD OCT PY 2000 IS 202 BP 64 EP 68 PG 5 WC Automation & Control Systems; Instruments & Instrumentation SC Automation & Control Systems; Instruments & Instrumentation GA 382AX UT WOS:000165797200003 ER PT J AU Daskalov, GM Baker, RS Rogers, DWO Williamson, JF AF Daskalov, GM Baker, RS Rogers, DWO Williamson, JF TI Dosimetric modeling of the microselectron high-dose rate Ir-192 source by the multigroup discrete ordinates method SO MEDICAL PHYSICS LA English DT Article DE multigroup discrete ordinates photon transport; Monte Carlo photon transport; photon kerma; absorbed dose; microSelectron Ir-192HDR source; brachytherapy dosimetry ID NEUTRON-CAPTURE THERAPY; BRACHYTHERAPY SOURCES; PHOTON TRANSPORT; EQUATIONS AB The DANTSYS multigroup discrete ordinates computer code is applied to quantitatively estimate the absorbed dose rate distributions in the vicinity of a microSelectron Ir-192 high-dose-rate (HDR) source in two-dimensional cylindrical R-Z geometry. The source is modeled in a cylindrical water phantom of diameter 20 cm and height 20 cm. The results are also used for evaluation of the Task Group 43 (TG-43) dosimetric quantities. The DANTSYS accuracy is estimated by direct comparisons with corresponding Monte Carlo results. Our 210-group photon cross section library developed previously, together with angular quadratures consisting of 36 (S-16) to 210 (S-40) directions and associated weights; per octant, are used in the DANTSYS simulations. Strong ray effects are observed but are significantly mitigated through the use of DANTSYS's stochastic ray-tracing first collision source algorithm. The DANTSYS simulations closely approximate Monte Carlo estimates of both direct dose calculations and TG-43 dosimetric quantities. The discrepancies with S-20 angular quadrature (55 directions and weights per octant) or higher are shown to be less than +/-5% (about 2.5 standard deviations of Monte Carlo calculations) everywhere except for limited regions along the Z axis of rotational symmetry, where technical limitations in the DANTSYS first collision source implementation makes adequate suppression of ray effects difficult to achieve. The efficiency of DANTSYS Simulations is compared with that of the EGS4 Monte Carlo code. It is demonstrated that even with the 210-group cross section library, DANTSYS achieves two-fold efficiency gains using the the S-20 quadrature set. The potential of discrete ordinates method for further efficiency improvements is also discussed. [S0094-2405(00)01510-8]. C1 Natl Res Council Canada, IRS, INMS, Ottawa, ON K1A 0R6, Canada. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Washington Univ, Sch Med, St Louis, MO 63110 USA. RP Daskalov, GM (reprint author), Natl Res Council Canada, IRS, INMS, 1500 Montreal Rd, Ottawa, ON K1A 0R6, Canada. RI Rogers, David/A-1973-2008 FU NCI NIH HHS [R01 CA46640] NR 37 TC 37 Z9 37 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD OCT PY 2000 VL 27 IS 10 BP 2307 EP 2319 DI 10.1118/1.1308279 PG 13 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 367YG UT WOS:000090089500015 PM 11099199 ER PT J AU Pogrebnjak, AD Ivanov, YF Lebed', AG Valyaev, AN Renk, T Tompson, MO Zhao, WJ AF Pogrebnjak, AD Ivanov, YF Lebed', AG Valyaev, AN Renk, T Tompson, MO Zhao, WJ TI Effect of intense pulse ion beam on carbon steel and stainless steel properties SO METALLOFIZIKA I NOVEISHIE TEKHNOLOGII LA Russian DT Article AB Fe56Cr18-Ni-16-Mn-10 single-crystal samples with crystallographic flats (111) and (100) (size 12x 12x 2 mm) and Steel 3 samples (size 16x22x2 mm) are irradiated by proton beam with 1 MeV energy. Structure and element composition analysis are performed by transmission electron microscopy, scanning electron microscopy, atomic force microscopy, Rutherford backscattering spectroscopy. The tests in microhardness, wear-and-tear resistance, and corrosion resistance are also used. The task of finding-the number of the evaporated material is determined numerically. Defect-structure and servicing-characteristics changes are revealed inside near surface and in the depth of near surface. C1 Sumy Surface Modificat Inst, UA-40030 Sumy, Ukraine. Tomsk Engn & Urban Planning Acad, Tomsk 634050, Russia. Sandia Natl Labs, Albuquerque, NM 87185 USA. Cornell Univ, Inst Math Sci, Ithaca, NY 14853 USA. Beijing Univ, Inst Heavy Ion Phys, Beijing 100871, Peoples R China. RP Pogrebnjak, AD (reprint author), Sumy Surface Modificat Inst, Prosp Shevchenko 17, UA-40030 Sumy, Ukraine. RI Ivanov, Yurii/A-9268-2014; Pogrebnjak, Alexander/O-1736-2015 OI Ivanov, Yurii/0000-0001-8022-7958; NR 10 TC 0 Z9 0 U1 0 U2 0 PU NATL ACAD SCIENCES UKRAINE, INST METAL PHYSICS PI KIEV 142 PA 36 ACADEMICIAN VERNADSKY BLVD, KIEV 142, UKRAINE UA-252180 SN 0204-3580 J9 METALLOFIZ NOV TEKH+ JI Metallofiz. Nov. Tekhnol.-Met. Phys. Adv. Techn. PD OCT PY 2000 VL 22 IS 10 BP 18 EP 24 PG 7 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 380WT UT WOS:000165727100004 ER PT J AU Cady, CM Chen, SR Gray, GT Korzekwa, DA Bingert, JF AF Cady, CM Chen, SR Gray, GT Korzekwa, DA Bingert, JF TI Dynamic materials testing, texture, and yield-surface calculation of an automotive sheet steel SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID LOW-CARBON STEEL; PLASTIC-DEFORMATION; STRAIN RATES; METALS; FLOW; FEATURES; CRITERIA; BEHAVIOR; TUBES AB The relationships between the stress state and anisotropic mechanical response for a drawing-quality, special-killed (DQSK) mild sheet steel has been analyzed. The strain rate and temperature sensitivity of the flow stress and the insensitivity of the strain hardening to strain rate are shown to be consistent with thermal activation over a Peierls barrier as the rate-controlling mechanism for deformation in DQSK. A calculated yield surface, using the quadratic Hill criterion, is shown to produce an accurate correlation with the experimental results as a function of stress state. Annealing of the DQSK sheet steel at 773 K for 1 hour reduced some of the residual stresses developed during the forming process, hut had little effect on the texture. The R values derived from computed yield surfaces suggested very little difference between in-plane (IP) and transverse tensile tests, consistent with the experimental results. A comparison of the stress-strain response with the calculated yield-surface and texture measurements correlates well with the relationships between the IP and through-thickness (TT) deformation. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Cady, CM (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. NR 41 TC 5 Z9 5 U1 1 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD OCT PY 2000 VL 31 IS 10 BP 2439 EP 2448 DI 10.1007/s11661-000-0189-9 PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 364WQ UT WOS:000089917400005 ER PT J AU Ur, SC Choo, H Lee, DB Nash, P AF Ur, SC Choo, H Lee, DB Nash, P TI Processing and properties of mechanically alloyed Ni(Fe)Al-Al2O3-AIN SO METALS AND MATERIALS-KOREA LA English DT Article DE mechanical alloying; nickel aluminides; dispersion strengthening; in-situ AlN and Al2O3 ID GRAIN-GROWTH; DUCTILITY AB Ni(Fe)Al powders containing a homogeneous distribution of in-situ formed AW and Al2O3 dispersoids were produced by a mechanical alloying process in a controlled atmosphere using a high energy attrition mill. The powders were successfully consolidated by either the hot pressing or hot extrusion process. The phase information investigated by TEM, XRD and a modified TGA analysis reveals that Fe can be soluble up to 19.2% to the NiAl phase(beta) at room temperature after the MA process. Subsequent thermomechanical treatment under specific conditions was tried so as to induce a secondary recrystallization to improve the high temperature properties. However, no clear evidence of abrupt grain coarsening was obtained, presumably due to the restricted condition for the boundary break-away mechanism in this material. The mechanical properties in terms of strength at room temperature as well as at high temperatures were shown to have improved through the addition of AlN, and room temperature ductility was also shown to have improved by the precipitation of the second phase of alpha in this material. C1 Chungju Natl Univ, Dept Mat Sci & Engn, Chungju 380702, South Korea. Los Alamos Natl Lab, Santa Fe, NM USA. Sungkyunkwan Univ, Sch Met & Mat Engn, Changan Ku, Suwon 440746, South Korea. IIT, Dept Mech Mat & Aerosp Engn, Chicago, IL 60616 USA. RP Ur, SC (reprint author), Chungju Natl Univ, Dept Mat Sci & Engn, 123 Gundan Ri, Chungju 380702, South Korea. RI Choo, Hahn/A-5494-2009 OI Choo, Hahn/0000-0002-8006-8907 NR 19 TC 3 Z9 3 U1 0 U2 3 PU KOREAN INST METALS MATERIALS PI SEOUL PA POSCO CENTER, 4TH FL (EAST WING), 892 DAECHI-4-DONG, KANGNAM-KU, SEOUL 135-777, SOUTH KOREA SN 1225-9438 J9 MET MATER-KOREA JI Met. Mater.-Korea PD OCT PY 2000 VL 6 IS 5 BP 435 EP 440 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 370MN UT WOS:000165127000006 ER PT J AU Ackerman, EJ Iakoucheva, LM AF Ackerman, EJ Iakoucheva, LM TI Nucleotide excision repair in oocyte nuclear extracts from Xenopus laevis SO METHODS-A COMPANION TO METHODS IN ENZYMOLOGY LA English DT Article ID DNA-POLYMERASE-ALPHA; BETA AB We have developed efficient DNA repair extracts derived from the unusually large nuclei of Xenopus oocytes. These extracts use nucleotide excision repair (NER) to completely remove bulky adducts from DNA. There is very little or no synthesis on control, undamaged DNA, indicating the extracts do not have significant nonspecific nuclease activity, and repair of cyclobutane pyrimidine dimers (CPDs) occurs in the dark, indicating that NER, and not photolyase, is responsible for CPD repair. The extracts can be inactivated with antibodies specific to repair proteins and then repair activity can be restored by adding purified recombinant protein. Here we describe detailed protocols for preparing Xenopus nuclear repair extracts. (C) 2000 Academic Press. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Ackerman, EJ (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. OI Iakoucheva, Lilia/0000-0002-4542-5219 NR 9 TC 6 Z9 6 U1 1 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1046-2023 J9 METHODS JI Methods PD OCT PY 2000 VL 22 IS 2 BP 188 EP 193 DI 10.1006/meth.2000.1060 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 366BJ UT WOS:000089984700011 PM 11020334 ER PT J AU Polette, LA Gardea-Torresdey, JL Chianelli, RR George, GN Pickering, IJ Arenas, J AF Polette, LA Gardea-Torresdey, JL Chianelli, RR George, GN Pickering, IJ Arenas, J TI XAS and microscopy studies of the uptake and bio-transformation of copper in Larrea tridentata (creosote bush) SO MICROCHEMICAL JOURNAL LA English DT Article DE creosote; Larrea tridentata; copper; phytoremediation; X-ray absorption spectroscopy ID RAY-ABSORPTION SPECTROSCOPY; THLASPI-CAERULESCENS; PHYTOREMEDIATION; CR(III); PLANTS AB Herein we present work directed toward understanding the mechanisms employed by Larrea tridentata (Creosote bush) to uptake and simultaneously defend against the presence of excess copper. The location and nature of copper in the plant have been studied on several length scales: greater than 10 mum (scanning electron microscopy), less than 10 mum (transmission electron microscopy) and atomic level structure and speciation (EXAFS and XANES). Two interesting results are apparent: creosote takes up or adsorbs copper from the soil in the Cu(II) oxidation state and transports it to the leaves where copper is found as Cu(I) and Cu(II). The transport agent appears to be a Cu phytochelatin. Additionally, creosote may be immobilizing and excreting copper via at least two additional mechanisms: storage of metals in vacuoles and excretion of copper into the sticky resinous substance found on the leaf surface. Creosote may also accumulate wind-blown particulates that can easily adhere to the resinous sticky surface of the plant. If, however, the particulates are < 10 m they may enter the leaf by respiration through the plant 'stomata' that have openings between 5 mum and 10 mum As such, creosote may be a natural bio-indicator for airborne particulates that are < 10 m. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Texas, Dept Chem & Environm Sci & Engn, El Paso, TX 79968 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Inst Nacl Invest Nucl, Mexico City 01000, DF, Mexico. RP Gardea-Torresdey, JL (reprint author), Univ Texas, Dept Chem & Environm Sci & Engn, El Paso, TX 79968 USA. RI George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Pickering, Ingrid/0000-0002-0936-2994 NR 27 TC 35 Z9 36 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0026-265X J9 MICROCHEM J JI Microchem J. PD OCT PY 2000 VL 65 IS 3 BP 227 EP 236 DI 10.1016/S0026-265X(00)00055-2 PG 10 WC Chemistry, Analytical SC Chemistry GA 382PG UT WOS:000165831000004 ER PT J AU Fisher, IR Kramer, MJ Goldman, AI AF Fisher, IR Kramer, MJ Goldman, AI TI Recent advances in the study of quasicrystals SO MICRON LA English DT Article; Proceedings Paper CT 14th International Congress on Electron Microscopy CY AUG 31-SEP 04, 1998 CL CANCUN, MEXICO SP Mexican Soc Microscopy, Consejo Nacl Ciencia & Tecnol, Inst Nacl Invest Nucl, Univ Autonoma Estado Mexico, Univ Veracruzana, Ctr Invest & Estudios Avanzados, Univ Nacl Autonoma Mexico, Ctr Invest Mat Avanzados, Inst Politecn Nacl, Univ Autonoma Nuevo Leon DE quasicrystal ID ICOSAHEDRAL QUASI-CRYSTALS; AL-NI-CO; R = Y; MG-ZN; TERNARY MELT; HO; TB; GROWTH; DY; ER AB Some recent advances in the study of quasicrystals at Ames Laboratory are reviewed. In particular, growth from the melt of large, high-quality, single-grain quasicrystals is described in detail for icosahedral R-Mg-Zn and decagonal Al-Ni-Co. In addition, the magnetic properties of the rare-earth-containing icosahedral R-Mg-Zn quasicrystals are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Fisher, IR (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 19 TC 7 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0968-4328 J9 MICRON JI Micron PD OCT PY 2000 VL 31 IS 5 BP 469 EP 473 DI 10.1016/S0968-4328(99)00126-2 PG 5 WC Microscopy SC Microscopy GA 314HJ UT WOS:000087050100003 ER PT J AU Luo, ZP Hashimoto, H AF Luo, ZP Hashimoto, H TI High-resolution electron microscopy observation of a new crystalline approximant W ' of Mg-Zn-Y icosahedral quasicrystal SO MICRON LA English DT Article; Proceedings Paper CT 14th International Congress on Electron Microscopy CY AUG 31-SEP 04, 1998 CL CANCUN, MEXICO SP Mexican Soc Microscopy, Consejo Nacl Ciencia & Tecnol, Inst Nacl Invest Nucl, Univ Autonoma Estado Mexico, Univ Veracruzana, Ctr Invest & Estudios Avanzados, Univ Nacl Autonoma Mexico, Ctr Invest Mat Avanzados, Inst Politecn Nacl, Univ Autonoma Nuevo Leon DE crystal; electron diffraction; high-resolution electron microscopy; Mg-Zn-Y; quasicrystal ID QUASI-CRYSTALS; RE ALLOYS; PHASE AB A new ordered structure W' with a lattice parameter (a = 2.05 nm) about three times as large as that of the fundamental face-centered cubic W phase (n = 0.6848 nm) has been found in the Mg-Zn-Y system by means of transmission electron microscopy. The W' and W phases have the cube-to-cube orientation relationship. Moreover, the strong electron diffraction spots of the W' phase showed pseudo-icosahedral symmetry, implying that it is a crystalline approximant of the Mg-Zn-Y icosahedral quasicrystal. In the high-resolution electron microscopic images of the W' phase, Penrose tiles of pentagons and boats with an edge length of a(p) = 0.481 nm can be identified. A binary tile of crown subunit has also been deduced from such a tiling. Translation domains of the W' phase have also been observed and the translation vectors at the domain boundary are: a(p), tau x a(p) and (1 + tau) x a(p), respectively, where (1 + tau) x a(p) equals to the edge length a(l) of the big obtuse rhombus of the W' phase and tau = (1 + root 5)/2, is the golden ratio. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Okayama Univ Sci, Okayama 700, Japan. Chinese Acad Sci, Beijing Lab Electron Microscopy, Beijing 100080, Peoples R China. Inst Aeronaut Mat, Beijing 100095, Peoples R China. RP Luo, ZP (reprint author), Argonne Natl Lab, Div Mat Sci, Bldg 223, Argonne, IL 60439 USA. RI Luo, Zhiping/C-4435-2014 OI Luo, Zhiping/0000-0002-8264-6424 NR 14 TC 16 Z9 20 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0968-4328 J9 MICRON JI Micron PD OCT PY 2000 VL 31 IS 5 BP 487 EP 492 DI 10.1016/S0968-4328(99)00128-6 PG 6 WC Microscopy SC Microscopy GA 314HJ UT WOS:000087050100005 ER PT J AU Lee, Y Parise, JB Tripathi, A Kim, SJ Vogt, T AF Lee, Y Parise, JB Tripathi, A Kim, SJ Vogt, T TI Synthesis and crystal structures of gallium and germanium variants of cancrinite SO MICROPOROUS AND MESOPOROUS MATERIALS LA English DT Article DE Cancrinite; cation coordination; DLS modeling; framework disordering; gallium; germanium; Ge(OH)(6); in situ synchrotron X-ray powder diffraction; nepheline hydrate I; resonant diffraction; thermogravimetry; T-O-T bond angle ID X-RAY; POWDER DIFFRACTION; RIETVELD ANALYSIS; BASIC CANCRINITE; IN-SITU; ZEOLITE AB A synthetic aluminogermanate and a gallogermanate with the Cancrinite group (CAN) framework topology have been synthesized under hydrothermal conditions and characterized by single crystal synchrotron X-ray diffraction. ALGe-CAN, Na6Cs2Al6Ge6O24. Ge(OH)(6), is hexagonal, with the space group P6(3) and a = 12.968(1), c = 5.132(1) Angstrom, V = 747.4(1) Angstrom(3). The T-sites exhibit complete ordering of Al and Ge atoms, similar to the framework models of aluminosilicate analogues. GaGe-CAN, Na6Cs2Ga6Ge6O24. Ge(OH)(6), is hexagonal, apparently with the space group P6(3)mc and a = 12.950(2), c = 5.117(1) Angstrom, V = 743.2(2) Angstrom(3). Although the observed data are consistent with the presence of the c-glide and consequent disordering of Ga and Ge atoms at the T-sites, calculation using a DLS-optimized framework in the space group P6(3) reveals that the intensities of the hh<(2h)over bar>l reflections with l = 2n + 1 are less than 0.07% of the strongest (0002) reflection, suggesting that P6(3) is probably the true space group. Resonant diffraction studies performed in the vicinity of the Ga K-edge confirmed the presence of the hh<(2h)over bar>l reflections with l2n + 1 and thus confirmed the ordering of the framework Ga/Ge atoms in GaGe-CAN. Inspection of the framework T-O-T bond angles demonstrates greater relative cell contraction for GaGe-CAN compared to AlGe-CAN and aluminosilicate counterparts. In both the structural models, Ge(OH)(6) octahedra are occluded in the 12-ring channels running along the 6(3)-axes. The sodium cations fully occupy the sites above the 6-ring windows in the 12-ring channels. The cesium cations fully occupy the sites in the middle of the cancrinite cages. Subtle differences in the coordination geometries of the extra-framework species are found, perhaps due to the pseudo-symmetry of GaGe-CAN. Thermogravimetry results indicate net weight losses of 3.5% and 3.0% for AlGe-CAN and GaGe-CAN, respectively, which are explainable by the dehydration of the Ge(OH)6 octahedra. In situ synchrotron X-ray powder diffraction demonstrated the formation of GaGe analogue of the nepheline hydrate I type structure at the temperature of complete dehydration. (C) 2000 Elsevier Science B.V. All rights reserved. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Parise, JB (reprint author), SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RI Vogt, Thomas /A-1562-2011; Lee, Yongjae/K-6566-2016 OI Vogt, Thomas /0000-0002-4731-2787; NR 36 TC 19 Z9 19 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-1811 J9 MICROPOR MESOPOR MAT JI Microporous Mesoporous Mat. PD OCT PY 2000 VL 39 IS 3 BP 445 EP 455 DI 10.1016/S1387-1811(00)00221-3 PG 11 WC Chemistry, Applied; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 361QU UT WOS:000089735100003 ER PT J AU Goldwyn, DL Cott, MB Olcott, MB Nanay, J Stauffer, TR AF Goldwyn, DL Cott, MB Olcott, MB Nanay, J Stauffer, TR TI The Caspian region and the new great powers SO MIDDLE EAST POLICY LA English DT Editorial Material C1 US DOE, Washington, DC 20585 USA. Carnegie Endowment Int Peace, Washington, DC 20036 USA. RP Goldwyn, DL (reprint author), US DOE, Washington, DC 20585 USA. NR 0 TC 35 Z9 35 U1 0 U2 1 PU MIDDLE EAST POLICY COUNCIL PI WASHINGTON PA 1730 M ST, NW, STE 512, WASHINGTON, DC 20036 USA SN 1061-1924 J9 MIDDLE EAST POLICY JI Middle East Policy PD OCT PY 2000 VL 7 IS 4 BP 1 EP 21 DI 10.1111/j.1475-4967.2000.tb00174.x PG 21 WC Area Studies; International Relations SC Area Studies; International Relations GA 371PB UT WOS:000165186400002 ER PT J AU Dave, V Zhao, C Yang, F Tung, CS Ma, J AF Dave, V Zhao, C Yang, F Tung, CS Ma, J TI Reprogrammable recognition codes in Bicoid homeodomain-DNA interaction SO MOLECULAR AND CELLULAR BIOLOGY LA English DT Article ID LEFT-RIGHT ASYMMETRY; HELIX-TURN-HELIX; DROSOPHILA EMBRYO; VND/NK-2 HOMEODOMAIN; ORTHODENTICLE GENE; CRYSTAL-STRUCTURE; ANGSTROM RESOLUTION; BINDING-SPECIFICITY; ANTERIOR PATTERN; PROTEIN AB We describe experiments to determine how the homeodomain of the Drosophila morphogenetic protein Bicoid recognizes different types of DNA sequences found in natural enhancers. Our chemical footprint analyses reveal that the Bicoid homeodomain makes both shared and distinct contacts with a consensus site A1 (TAATCC) and a nonconsensus site X1 (TAAGCT). In particular, the guanine of X1 at position 4 (TAAGCT) is protected by Bicoid homeodomain. We provide further evidence suggesting that the unique arginine at position 54 (Arg 54) of the Bicoid homeodomain enables the protein to recognize X1 by specifically interacting with this position 4 guanine. We also describe experiments to analyze the contribution of artificially introduced Arg 54 to DNA recognition by other Bicoid-related homeodomains, including that from the human disease protein Pitx2. Our experiments demonstrate that the role of Arg 54 varies depending on the exact homeodomain framework and DNA sequences. Together, our results suggest that Bicoid and its related homeodomains utilize distinct recognition codes to interact with different DNA sequences, underscoring the need to study DNA recognition by Bicoid-class homeodomains in an individualized manner. C1 Childrens Hosp Res Fdn, Div Dev Biol, Cincinnati, OH 45229 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Dave, V (reprint author), Childrens Hosp Res Fdn, Div Dev Biol, 3333 Burnet Ave, Cincinnati, OH 45229 USA. RI Zhao, Chen/A-9987-2011; Dave, Vrushank/K-5262-2012 OI Dave, Vrushank/0000-0003-4044-2658 FU NIEHS NIH HHS [P30 ES006096, P30 ES06096]; NIGMS NIH HHS [R01 GM52467] NR 78 TC 30 Z9 30 U1 0 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0270-7306 J9 MOL CELL BIOL JI Mol. Cell. Biol. PD OCT PY 2000 VL 20 IS 20 BP 7673 EP 7684 DI 10.1128/MCB.20.20.7673-7684.2000 PG 12 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 357MB UT WOS:000089504500025 PM 11003663 ER PT J AU Abreu, IA Saraiva, LM Carita, J Huber, H Stetter, KO Cabelli, D Teixeira, M AF Abreu, IA Saraiva, LM Carita, J Huber, H Stetter, KO Cabelli, D Teixeira, M TI Oxygen detoxification in the strict anaerobic archaeon Archaeoglobus fulgidus: superoxide scavenging by Neelaredoxin SO MOLECULAR MICROBIOLOGY LA English DT Article ID DESULFOVIBRIO-DESULFURICANS ATCC-27774; NONHEME IRON PROTEIN; RBO GENE-PRODUCT; ESCHERICHIA-COLI; GIGAS; RUBREDOXIN; DISMUTASE; DESULFOFERRODOXIN; DESULFOREDOXIN; PURIFICATION AB Archaeoglobus fulgidus is a hyperthermophilic sulphate-reducing archaeon. It has an optimum growth temperature of 83 degreesC and is described as a strict anaerobe. Its genome lacks any homologue of canonical superoxide (O-2 .(-)) dismutases. In this work, we show that neelaredoxin (Nlr) is the main O-2 .(-) scavenger in A. fulgidus, by studying both the wild-type and recombinant proteins. Nlr is a 125-amino-acid blue-coloured protein containing a single iron atom/molecule, which in the oxidized state is high spin ferric. This iron centre has a reduction potential of +230 mV at pH 7.0. Nitroblue tetrazolium-stained gel assays of cell-soluble extracts show that Nlr is the main protein from A. fulgidus which is reactive towards O-2 .(-). Furthermore, it is shown that Nlr is able to both reduce and dismutate O-2 .(-), thus having a bifunctional reactivity towards O-2 .(-). Kinetic and spectroscopic studies indicate that Nlr's superoxide reductase activity may allow the cell to eliminate O-2 .(-) quickly in a NAD(P)H-dependent pathway. On the other hand, Nlr's superoxide dismutation activity will allow the cell to detoxify O-2 .(-) independently of the cell redox status. Its superoxide dismutase activity was estimated to be 59 U mg(-1) by the xanthine/xanthine oxidase assay at 25 degreesC. Pulse radiolysis studies with the isolated and reduced Nlr proved unambiguously that it has superoxide dismutase activity; at pH 7.1 and 83 degreesC, the rate constant is 5 x 10(6) M-1 s(-1). Besides the superoxide dismutase activity, soluble cell extracts of A. fulgidus also exhibit catalase and NAD(P)H/oxygen oxidoreductase activities. By putting these findings together with the entire genomic data available, a possible oxygen detoxification mechanism in A. fulgidus is discussed. C1 Univ Nova Lisboa, Inst Tecnol Quim & Biol, P-2780156 Oeiras, Portugal. Univ Regensburg, Lehrstuhl Mikrobiol, D-93053 Regensburg, Germany. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Teixeira, M (reprint author), Univ Nova Lisboa, Inst Tecnol Quim & Biol, Rua Quinta Grande 6, P-2780156 Oeiras, Portugal. RI Saraiva, Ligia/H-8537-2012; Teixeira, Miguel/A-9098-2011; Abreu, Isabel/I-5081-2013 OI Saraiva, Ligia/0000-0002-0675-129X; Teixeira, Miguel/0000-0003-4124-6237; Abreu, Isabel/0000-0002-5566-2146 NR 32 TC 62 Z9 63 U1 0 U2 7 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0950-382X J9 MOL MICROBIOL JI Mol. Microbiol. PD OCT PY 2000 VL 38 IS 2 BP 322 EP 334 DI 10.1046/j.1365-2958.2000.02121.x PG 13 WC Biochemistry & Molecular Biology; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 366DW UT WOS:000089990400013 PM 11069658 ER PT J AU Muller, V Arbabi-Bidgoli, S Einasto, J Tucker, D AF Muller, V Arbabi-Bidgoli, S Einasto, J Tucker, D TI Voids in the Las Campanas Redshift Survey versus cold dark matter models SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : formation; dark matter; large-scale structure of Universe ID LARGE-SCALE STRUCTURE; N-BODY SIMULATIONS; SPATIAL-DISTRIBUTION; POWER SPECTRA; GALAXIES; UNIVERSE; SUPERCLUSTERS; EVOLUTION; NORMALIZATION; HIERARCHY AB We analysed the distribution of void sizes in the two-dimensional slices of the Las Campanas Redshift Survey (LCRS). Fourteen volume-limited subsamples were extracted from the six slices to cover a large part of the survey and to test the robustness of the results against cosmic variance. Thirteen samples were randomly culled to produce homogeneously selected samples. We then studied the relationship between the cumulative area covered by voids and the void size as a property of the void hierarchy. We found that the distribution of void sizes scaled with the mean galaxy separation, lambda. In particular, we found that the size of voids covering half of the area is given by D-med approximate to lambda + (12 +/- 3) h(-1) Mpc. Next, by employing an environmental density threshold criterion to identify mock galaxies, we were able to extend this analysis to mock samples from dynamical N-body simulations of cold dark matter (CDM) models. To reproduce the observed void statistics, overdensity thresholds of delta(th) approximate to 0, ..., 1 are necessary. We compared standard (SCDM), open (OCDM), vacuum energy dominated (Lambda CDM) and broken scale invariant CDM models (BCDM): we found that both the void size distribution and the two-point correlation function provided important and complementary information on the large-scale matter distribution. The dependence of the void statistics on the threshold criterion for the mock galaxy identification showed that the galaxy biasing was more crucial for the void size distribution than were differences between the cosmological models. C1 Astrophys Inst Potsdam, D-14482 Potsdam, Germany. Tartu Observ, EE-61602 Toravere, Estonia. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. RP Muller, V (reprint author), Astrophys Inst Potsdam, Sternwarte 16, D-14482 Potsdam, Germany. NR 54 TC 49 Z9 49 U1 0 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD OCT PY 2000 VL 318 IS 1 BP 280 EP 288 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 363VB UT WOS:000089857400033 ER PT J AU Reisner, J Wynne, S Margolin, L Linn, R AF Reisner, J Wynne, S Margolin, L Linn, R TI Coupled atmospheric-fire modeling employing the method of averages SO MONTHLY WEATHER REVIEW LA English DT Article ID ELASTIC EQUATIONS; TIME AB A conservative forward-in-time numerical technique to improve the efficiency of a fully compressible wildfire model is presented. The technique is based on a method of averaging (MOA), which allows the costly advective terms based on a synchronous advection algorithm (e.g., the monotonicity of scalar fields is preserved) to be computed on a time step several rimes larger than would be dictated by the speed of the fastest waves. The MOA technique is explicit and does not require the use of either direct or iterative solvers to invert a matrix; instead the governing equations are solved to first order within an inner loop in which time-averaged quantities are obtained for use in a more costly outer loop. A linearized stability analysis of the entire scheme, including the interaction of gravity wave propagation and material motion, is presented and numerical stability for a wide range of physical and numerical parameters is demonstrated. Convergence studies are used to verify that the overall method maintains second-order accuracy. A model to simulate the propagation of the firefront in wildfires is described, and several calculations are provided to illustrate the application and advantages of the MOA in a problem that includes many complex physical processes. C1 Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Los Alamos, NM 87545 USA. RP Reisner, J (reprint author), Univ Calif Los Alamos Natl Lab, Div Earth & Environm Sci, Box 1663,Mail Stop D401, Los Alamos, NM 87545 USA. NR 15 TC 22 Z9 22 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 2000 VL 128 IS 10 BP 3683 EP 3691 DI 10.1175/1520-0493(2001)129<3683:CAFMET>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 367AY UT WOS:000090040300021 ER PT J AU Smith, RD AF Smith, RD TI Probing proteomes - seeing the whole picture? SO NATURE BIOTECHNOLOGY LA English DT News Item ID MASS-SPECTROMETRY; PROTEIN; IDENTIFICATION; YEAST C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 10 TC 42 Z9 46 U1 0 U2 0 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1087-0156 J9 NAT BIOTECHNOL JI Nat. Biotechnol. PD OCT PY 2000 VL 18 IS 10 BP 1041 EP 1042 DI 10.1038/80226 PG 2 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 361VJ UT WOS:000089744700022 PM 11017038 ER PT J AU Han, BG Nunomura, W Takakuwa, Y Mohandas, N Jap, BK AF Han, BG Nunomura, W Takakuwa, Y Mohandas, N Jap, BK TI Protein 4.1R core domain structure and insights into regulation of cytoskeletal organization SO NATURE STRUCTURAL BIOLOGY LA English DT Article ID BINDING INTERFACE; PEPTIDE COMPLEX; CALMODULIN; KINASE; RECOGNITION; NMR; IDENTIFICATION; MODULATION; MAD AB The crystal structure of the core domain (N-terminal 30 kDa domain) of cytoskeletal protein 4.1R has been determined and shows a cloverleaf-like architecture. Each lobe of the cloverleaf contains a specific binding site for either band 3, glycophorin C/D or p55. At a central region of the molecule near where the three lobes are joined are two separate calmodulin (CaM) binding regions. One of these is composed primarily of an alpha-helix and is Ca2+ insensitive; the other takes the form of an extended structure and its binding with CaM is dramatically enhanced by the presence of Ca2+, resulting in the weakening of protein 4.1R binding to its target proteins. This novel architecture, in which the three lobes bind with three membrane associated proteins, and the location of calmodulin binding sites provide insight into how the protein 4.1R core domain interacts with membrane proteins and dynamically regulates cell shape in response to changes in intracellular Ca2+ levels. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Tokyo Womens Med Univ, Dept Biochem, Tokyo 1628666, Japan. RP Jap, BK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RI Han, Bong-Gyoon/J-9120-2012 NR 23 TC 98 Z9 100 U1 0 U2 0 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD OCT PY 2000 VL 7 IS 10 BP 871 EP 875 PG 5 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 362LR UT WOS:000089779900016 PM 11017195 ER PT J AU Christendat, D Yee, A Dharamsi, A Kluger, Y Savchenko, A Cort, JR Booth, V Mackereth, CD Saridakis, V Ekiel, I Kozlov, G Maxwell, KL Wu, N McIntosh, LP Gehring, K Kennedy, MA Davidson, AR Pai, EF Gerstein, M Edwards, AM Arrowsmith, CH AF Christendat, D Yee, A Dharamsi, A Kluger, Y Savchenko, A Cort, JR Booth, V Mackereth, CD Saridakis, V Ekiel, I Kozlov, G Maxwell, KL Wu, N McIntosh, LP Gehring, K Kennedy, MA Davidson, AR Pai, EF Gerstein, M Edwards, AM Arrowsmith, CH TI Structural proteomics of an archaeon SO NATURE STRUCTURAL BIOLOGY LA English DT Article ID PROTEIN-STRUCTURE; ALIGNMENT; GENOMICS; CLASSIFICATION; PREDICTION; SCOP; GENE AB A set of 424 nonmembrane proteins from Methanobacterium thermoautotrophicum were cloned, expressed and purified for structural studies. Of these, similar to 20% were found to be suitable candidates for X-ray crystallographic or NMR spectroscopic analysis without further optimization of conditions, providing an estimate of the number of the most accessible structural targets in the proteome. A retrospective analysis of the experimental behavior of these proteins suggested some simple relations between sequence and solubility. implying that data bases of protein properties will be useful in optimizing high throughput strategies. Of the first 10 structures determined, several provided clues to biochemical functions that were not detectable from sequence analysis, and in many cases these putative functions could be readily confirmed by biochemical methods. This demonstrates that structural proteomics is feasible and can play a central role in functional genomics, C1 Univ Toronto, Ontario Canc Inst, Toronto, ON M5G 2M9, Canada. Univ Toronto, Dept Med Biophys, Toronto, ON M5G 2M9, Canada. Yale Univ, Dept Mol Biophys & Biochem & Comp Sci, New Haven, CT 06520 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ British Columbia, Dept Biochem & Mol Biol, Vancouver, BC V6T 1Z3, Canada. Univ British Columbia, Dept Chem, Vancouver, BC V6T 1Z3, Canada. Univ British Columbia, Biotechnol Lab, Vancouver, BC V6T 1Z3, Canada. Natl Res Council Canada, Biotechnol Res Inst, Montreal, PQ H4P 2R2, Canada. McGill Univ, Dept Biochem, Montreal, PQ H3G 1Y6, Canada. McGill Univ, Montreal Joint Ctr Struct Biol, Montreal, PQ H3G 1Y6, Canada. Univ Toronto, Dept Biochem, Toronto, ON M5S 1A8, Canada. Univ Toronto, Dept Mol & Med Genet, Toronto, ON M5S 1A8, Canada. Univ Toronto, Banting & Best Dept Med Res, CH Best Inst, Toronto, ON M5G 1L6, Canada. RP Univ Toronto, Ontario Canc Inst, 610 Univ Ave, Toronto, ON M5G 2M9, Canada. EM aled.edwards@utoronto.ca; carrow@oci.utoronto.ca RI Pai, Emil/D-2526-2013; Mackereth, Cameron/F-7946-2013; Gehring, Kalle/I-4403-2013; OI Mackereth, Cameron/0000-0002-0776-7947; Gehring, Kalle/0000-0001-6500-1184; Pai, Emil/0000-0002-1162-7242 NR 29 TC 227 Z9 246 U1 0 U2 9 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK ST, 9TH FLR, NEW YORK, NY 10013-1917 USA SN 1072-8368 J9 NAT STRUCT BIOL JI Nat. Struct. Biol. PD OCT PY 2000 VL 7 IS 10 BP 903 EP 909 PG 7 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 362LR UT WOS:000089779900022 PM 11017201 ER PT J AU Gat, U Engel, JR AF Gat, U Engel, JR TI Non-proliferation attributes of molten salt reactors SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article AB Molten salt reactors (MSR) have many non-proliferation attributes. They can operate on the thorium-uranium fuel cycle which protects the fissile material by the daughter products of the inseparable U-232. MSRs can completely fission all plutonium and HEU, and as desired, 'convert' them to U-233. This also results in high, and efficient resource utilization, while diminishing the plutonium stock. (On Pine processing, when applied, could free the waste from all fissile material. The fuel in the reactor stays protected by the intense radiation of the fission products. Fuel can also be protected in the reactor as well as outside the reactor by denaturing with natural uranium. A wide variety of MSRs are available, from 'once through' minimum processing reactors to ones with fuel processing which can breed fuel for converters. MSRs are extremely safe and simple reactors with good economic potential. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Gat, U (reprint author), Oak Ridge Natl Lab, POB 2009, Oak Ridge, TN 37831 USA. NR 19 TC 6 Z9 6 U1 2 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD OCT PY 2000 VL 201 IS 2-3 BP 327 EP 334 DI 10.1016/S0029-5493(00)00276-4 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 348NZ UT WOS:000088992600013 ER PT J AU Semertzidis, YK Castillo, V Kowalski, L Kraus, DE Larsen, R Lazarus, DM Magurno, B Nikas, D Ozben, C Srinivasan-Rao, T Tsang, T AF Semertzidis, YK Castillo, V Kowalski, L Kraus, DE Larsen, R Lazarus, DM Magurno, B Nikas, D Ozben, C Srinivasan-Rao, T Tsang, T TI Electro-optical detection of charged particles SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE electro-optical devices; charged particle detectors; charged particle tracking; picosecond techniques ID FIBER C1 Brookhaven Natl Lab, Collider Accelerator Dept, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Montclair State Univ, Dept Math Sci, Upper Montclair, NJ 07043 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Brookhaven Natl Lab, Instrumentat Div, Upton, NY 11973 USA. RP Lazarus, DM (reprint author), Brookhaven Natl Lab, Collider Accelerator Dept, POB 5000, Upton, NY 11973 USA. RI Semertzidis, Yannis K./N-1002-2013 NR 11 TC 9 Z9 9 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 2000 VL 452 IS 3 BP 396 EP 400 DI 10.1016/S0168-9002(00)00456-3 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 360PB UT WOS:000089675500002 ER PT J AU Dezillie, B Eremin, V Li, Z Verbitskaya, E AF Dezillie, B Eremin, V Li, Z Verbitskaya, E TI Polarization of silicon detectors by minimum ionizing particles SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE silicon detectors; charge collection efficiency; transient current technique; electric field distribution; polarization; non-equilibrium carrier trapping ID N-EFF; RADIATION HARDNESS; DEFECT ANALYSIS; FAST-NEUTRONS; DEEP LEVELS; RESISTIVITY; TEMPERATURES; DAMAGE; TCT AB This work presents quantitative predictions of the properties of highly irradiated (e.g. by high-energy particles. up to an equivalent fluence of 1 x 10(14) n cm(-2)) silicon detectors operating at cryogenic temperature. It is shown that the exposure to the Minimum Ionising Particle (MIP) with counting rates of about 10(6) cm(-2) s(-1) can influence the electric field distribution in the detector's sensitive volume. This change in the electric field distribution and its effect on the charge collection efficiency are discussed in the frame of a model based on trapping of carriers generated by MIPs. The experiment was performed at 87 K with an infrared (1030 nm) laser to simulate MIPs. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Russian Acad Sci, Ioffe Physicotech Inst, St Petersburg 194021, Russia. RP Dezillie, B (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Verbitskaya, Elena/D-1521-2014 NR 16 TC 33 Z9 33 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD OCT 1 PY 2000 VL 452 IS 3 BP 440 EP 453 DI 10.1016/S0168-9002(00)00450-2 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 360PB UT WOS:000089675500006 ER PT J AU Ognibene, TJ Brown, TA Knezovich, JP Roberts, ML Southon, JR Vogel, JS AF Ognibene, TJ Brown, TA Knezovich, JP Roberts, ML Southon, JR Vogel, JS TI Ion-optics calculations of the LLNL AMS system for biochemical C-14 measurements SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE ion-optics; computer modeling; accelerator mass spectrometry AB A dedicated AMS system for biochemical C-14 measurements is being built at the Center for Accelerator Mass Spectrometry. The system is centered around a National Electrostatics Corporation Model 3SDH-1 1-MV Pelletron accelerator and is designed to accept two ion sources. The LLNL 64-sample Cs-sputter ion source with its zoom lens beam line is attached to one port of the electrostatic switching element. To insure efficient coupling of the source to the acceptance of the accelerator, ion-optics calculations of the low-energy injection beam line have been conducted; the results of which were used to determine the layout of the ion-optical components of the beam line. Beam tests of the low-energy injection line show that beam behavior was accurately predicted by the calculations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Ognibene, TJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, L-397,POB 808, Livermore, CA 94551 USA. NR 11 TC 11 Z9 11 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 47 EP 51 DI 10.1016/S0168-583X(00)00151-8 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000010 ER PT J AU Wendt, K Trautmann, N Bushaw, BA AF Wendt, K Trautmann, N Bushaw, BA TI Resonant laser ionization mass spectrometry: An alternative to AMS? SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE ultratrace detection; resonance ionization spectroscopy; mass spectrometry ID TRACE ANALYSIS; ULTRATRACE DETERMINATION; ENVIRONMENTAL-SAMPLES; SPECTROSCOPY; ISOTOPES; SR-90; CA-41; PLUTONIUM; BEAM; PHOTOIONIZATION AB Resonant laser ionization mass spectrometry (RIMS) has developed into a versatile experimental method particularly concerning applications for highly selective ultratrace analysis. Apart from providing nearly complete isobaric suppression and high overall efficiency, the possibility for combining optical isotopic selectivity with that of the mass spectrometer leads to remarkable specifications. The widespread analytical potential and applicability of different techniques based on resonant laser ionization is demonstrated in investigations on stable and radioactive ultratrace isotopes with the focus on applications which require high selectivity, concerning, e.g., the noble gas isotopes Kr-81,Kr-85, PU isotopes, Sr-89,Sr-90, Tc-99 and Ca-41. Selective ultratrace determination of these radioisotopes provides access to a variety of fundamental research problems in environmental sciences, geo- and cosmochemistry, archaeology and biomedicine, which previously were often an exclusive domain for accelerator mass spectrometry (AMS), (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Mainz, Inst Phys, D-55099 Mainz, Germany. Univ Mainz, Inst Kernchem, D-55128 Mainz, Germany. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Wendt, K (reprint author), Univ Mainz, Inst Phys, Staudinger Weg 7, D-55099 Mainz, Germany. RI Wendt, Klaus/D-7306-2011 OI Wendt, Klaus/0000-0002-9033-9336 NR 30 TC 36 Z9 36 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 162 EP 169 DI 10.1016/S0168-583X(00)00127-0 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000028 ER PT J AU Bailey, K Chen, CY Du, X Li, YM Lu, ZT O'Connor, TP Young, L AF Bailey, K Chen, CY Du, X Li, YM Lu, ZT O'Connor, TP Young, L TI ATTA - A new method of ultrasensitive isotope trace analysis SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE atom trap trace analysis (ATTA); magneto-optical trap; Kr-85; Kr-81 AB A new method of ultrasensitive isotope trace analysis has been developed. This method, based on the technique of laser manipulation of neutral atoms, has been used to count individual Kr-85 and Kr-81 atoms present in a natural krypton gas sample with isotopic abundances in the range of 10(-11) and 10(-13), respectively. This method is free of contamination from other isotopes and elements and can be applied to various different isotope tracers for a wide range of applications. The demonstrated detection efficiency is 1 x 10(-7). System improvements could increase the efficiency by many orders of magnitude. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Lu, ZT (reprint author), Argonne Natl Lab, Div Phys, Bldg 203,9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 13 Z9 13 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 224 EP 227 DI 10.1016/S0168-583X(00)00215-9 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000038 ER PT J AU Southon, J Roberts, M AF Southon, J Roberts, M TI Ten years of sourcery at CAMS/LLNL - Evolution of a Cs ion source SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE accelerator mass spectrometry; mass spectrometry; ion sources ID LLNL AB The present performance and status of the LLNL AMS ion source and the rationale for the series of changes which led to the present design are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr AMS, Livermore, CA 94550 USA. RP Southon, J (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr AMS, POB 808,L-397, Livermore, CA 94550 USA. NR 6 TC 40 Z9 40 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 257 EP 261 DI 10.1016/S0168-583X(00)00345-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000044 ER PT J AU Roberts, ML Hamm, RW Dingley, KH Chiarappa-Zucca, ML Love, AH AF Roberts, ML Hamm, RW Dingley, KH Chiarappa-Zucca, ML Love, AH TI A compact tritium AMS system SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE accelerator mass spectrometry; biomedical instrumentation ID ACCELERATOR MASS-SPECTROMETRY AB Tritium (H-3) is a radioisotope that is extensively utilized in biological and environmental research. For biological research, 3H is generally quantified by liquid scintillation counting requiring gram-sized samples and counting times of several hours. For environmental research, H-3 is usually quantified by He-3 in-growth which requires gram-sized samples and in-growth times of several months. In contrast, provisional studies at LLNL's Center for Accelerator Mass Spectrometry have demonstrated that accelerator mass spectrometry (AMS) can be used to quantify 3H in milligram-sized biological samples with a 100 to 1000-fold improvement in detection limits when compared to scintillation counting. This increased sensitivity is expected to have great impact on the biological and environmental research community. However, in order to make the 3H AMS technique more broadly accessible, smaller, simpler, and less expensive AMS instrumentation must be developed. To meet this need, a compact, relatively low cost prototype 3H AMS system has been designed and built based on an LLNL ion source/sample changer and an AccSys Technology radio frequency quadrupole (RFQ) linac. With the prototype system, H-3/H-1 ratios ranging from 1 x 10(-10) to 1 x 10(-13) have be measured from milligram-sized samples. With improvements in system operation and sample preparation methodology, the sensitivity limit of the system is expected to increase to approximately 1 x 10(-15). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. AccSys Technol Inc, Pleasanton, CA 94566 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. RP Roberts, ML (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,L-397, Livermore, CA 94550 USA. NR 12 TC 10 Z9 10 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 262 EP 267 DI 10.1016/S0168-583X(00)00094-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000045 ER PT J AU Bergquist, BA Marchetti, AA Martinelli, RE McAninch, JE Nimz, GJ Proctor, ID Southon, JR Vogel, JS AF Bergquist, BA Marchetti, AA Martinelli, RE McAninch, JE Nimz, GJ Proctor, ID Southon, JR Vogel, JS TI Technetium measurements by accelerator mass spectrometry at LLNL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE technetium; Tc-99; niobium; peroxoniobium; fission products; radiochemistry; trace detection; accelerator mass spectrometry (AMS) ID AMS FACILITY; TC-99; PLUTONIUM AB Technetium-99 is a long-lived, high-abundance fission product which has been widely distributed in the environment through atmospheric testing, the nuclear fuel cycle, and nuclear medicine. It has a high potential for migration in the environment as the pertechnetate anion. At the Center for Accelerator Mass Spectrometry, methods are being developed for the detection of this radionuclide by accelerator mass spectrometry (AMS), including extraction from environmental samples, concentration and purification of the Tc-99, conversion to a form appropriate for AMS analysis, and quantification by AMS. Besides interference from the stable (though relatively rare) atomic isobar Ru-99, the detection of Tc-99 by AMS presents some technical challenges which are not present for the other radionuclides typically measured by AMS. These challenges are related to the lack of a stable Tc isotope. Here we present the status of our Tc-99 methods including discussion of interferences and sensitivity, and recent results for environmental samples and the IAEA reference material IAEA-381, Irish Sea Water. Sensitivity is presently similar to 10 mu Bq (similar to 1 x 10(8) atoms) per sample, limited primarily by 99Ru introduced from process chemicals, and precision/reproducibility is similar to 15-25%. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessment Div, Livermore, CA 94550 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Univ Calif Lawrence Livermore Natl Lab, Geosci & Environm Technol Div, Livermore, CA 94550 USA. RP McAninch, JE (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. NR 18 TC 18 Z9 18 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 328 EP 332 DI 10.1016/S0168-583X(00)00084-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000056 ER PT J AU Brown, TA Gillespie, GH AF Brown, TA Gillespie, GH TI Optics elements for modeling electrostatic lenses and accelerator components: III. Electrostatic deflectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE mass spectrometry; computer codes; electrostatic optics; beam deflectors AB Ion-beam optics models for simulating electrostatic prisms (deflectors) of different geometries have been developed for the envelope (matrix) computer code TRACE 3-D as a part of the development of a suite of electrostatic beamline element models which includes lenses, acceleration columns, quadrupoles and prisms. The models for electrostatic prisms are described in this paper. The electrostatic prism model options allow the first-order modeling of cylindrical, spherical and toroidal electrostatic deflectors. The application of these models in the development of ion-beam transport systems is illustrated through the modeling of a spherical electrostatic analyzer as a component of the new low-energy beamline at the Center for Accelerator Mass Spectrometry. Although initial tests following installation of the new beamline showed that the new spherical electrostatic analyzer was not behaving as predicted by these first-order models, operational conditions were found under which the analyzer now works properly as a double-focusing spherical electrostatic prism. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. GH Gillespie Associates, Del Mar, CA 92014 USA. RP Brown, TA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,L-397, Livermore, CA 94551 USA. NR 9 TC 4 Z9 4 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 338 EP 343 DI 10.1016/S0168-583X(00)00097-5 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000058 ER PT J AU Brown, TA Roberts, ML Southon, JR AF Brown, TA Roberts, ML Southon, JR TI Ion-source modeling and improved performance of the CAMS high-intensity Cs-sputter ion source SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE ion sources; charged-particle beam sources; mass spectrometry; computer codes ID LLNL AB The interior of the high-intensity Cs-sputter source used in routine operations at the Center for Accelerator Mass Spectrometry (CAMS) has been computer modeled using the program NEDLab, with the aim of improving negative ion output. Space charge effects on ion trajectories within the source were modeled through a successive iteration process involving the calculation of ion trajectories through Poisson-equation-determined electric fields, followed by calculation of modified electric fields incorporating the charge distribution from the previously calculated ion trajectories. The program has several additional features that are useful in ion source modeling: (1) averaging of space charge distributions over successive iterations to suppress instabilities, (2) Child's Law modeling of space charge limited ion emission from surfaces, and (3) emission of particular ion groups with a thermal energy distribution and at randomized angles. The results of the modeling effort indicated that significant modification of the interior geometry of the source would double Cs+ ion production from our spherical ionizer and produce a significant increase in negative ion output from the source. The results of the implementation of the new geometry were found to be consistent with the model results. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Brown, TA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,7000 East Ave, Livermore, CA 94551 USA. NR 3 TC 14 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 344 EP 349 DI 10.1016/S0168-583X(00)00202-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000059 ER PT J AU Roberts, ML Caffee, MW AF Roberts, ML Caffee, MW TI I-129 interlaboratory comparison: Phase II results SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE accelerator mass spectrometry; iodine-129; nuclear non-proliferation AB Large discrepancies seen in a Phase I I-129 Accelerator Mass Spectrometry (AMS) interlaboratory comparison have prompted a subsequent Phase II comparison. In Phase II of the I-129 AMS interlaboratory comparison, three separate laboratories prepared AgI from two environmental samples (IAEA 375 soil and maple leaves). Each laboratory used its own chemical preparation method; each of these methods being considerably different. The resulting six samples (two sets of three) were then distributed to the participating I-129 AMS facilities and I-129/I-127 ratios measured. Results and discussion of the Phase II interlaboratory comparison are presented. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Roberts, ML (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,L-397, Livermore, CA 94551 USA. RI Caffee, Marc/K-7025-2015 OI Caffee, Marc/0000-0002-6846-8967 NR 4 TC 14 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 388 EP 394 DI 10.1016/S0168-583X(00)00211-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000067 ER PT J AU Nishiizumi, K Caffee, MW DePaolo, DJ AF Nishiizumi, K Caffee, MW DePaolo, DJ TI Preparation of Ca-41 AMS standards SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE cosmogenic nuclide; standard; surface ionization mass spectrometry; Ca-41 ID ACCELERATOR MASS-SPECTROMETRY; HALF-LIFE; COSMOGENIC CA-41; BE-10 AB Absolute accelerator mass spectrometry (AMS) measurements require reliable standards for calibration. The Space Sciences Laboratory at the University of California, Berkeley, and the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory (LLNL) have prepared new Ca-41 AMS standards. The highly enriched (CaCO3)-Ca-41 was obtained from Oak Ridge National Laboratory. After purification of the CaCO3, the precise Ca-41/Ca ratio in the original material was determined by surface ionization mass spectrometry. The Ca-41 was sequentially diluted with natural Ca to obtain Ca-41/Ca ratios of 1.155 x 10(-10) 9.755 x 10(-12) 5.139 x 10(-12) 1.095 x 10(-12) and 5.884 x 10(-13). A solution with a Ca-41/Ca ratio of 10(-6) was also prepared for biomedical research. The solutions having Ca-41/Ca ratios between 10(-10) and 10(-12) were measured by AMS. Although the present blank level, 5 x 10(-14) Ca-41/Ca, was higher than anticipated, excellent linearity was obtained from 6 x 10(-13) to 1.2 x 10(-10) Ca-41/Ca. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Geol & Geophys, Berkeley, CA 94720 USA. EO Lawrence Berkeley Natl Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Nishiizumi, K (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI Caffee, Marc/K-7025-2015 OI Caffee, Marc/0000-0002-6846-8967 NR 15 TC 36 Z9 37 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 399 EP 403 DI 10.1016/S0168-583X(00)00150-6 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000069 ER PT J AU Buchholz, BA Freeman, SPHT Haack, KW Vogel, JS AF Buchholz, BA Freeman, SPHT Haack, KW Vogel, JS TI Tips and traps in the C-14 bio-AMS preparation laboratory SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE AMS; monitor; contamination; sample preparation ID GRAPHITE AB Maintaining a contamination free sample preparation lab for biological C-14 AMS requires the same or more diligence as a radiocarbon dating prep lab. Isotope ratios of materials routinely range over 4-8 orders of magnitude in a single experiment, dosing solutions contain thousands of DPM and gels used to separate proteins possess C-14 ratios of 1 amol C-14/mg C. Radiocarbon contamination is a legacy of earlier tracer work in most biological laboratories, even if they were never hot labs. Removable surface contamination can be found and monitored using swipes. Contamination can be found on any surface routinely touched: door knobs, light switches, drawer handles, water faucets. In general, all surfaces routinely touched need to be covered with paper, foil or plastic that can be changed frequently. Shared air supplies can also present problems by distributing hot aerosols throughout a building. Aerosols can be monitored for C-14 content using graphitized coal or fullerene soot mixed with metal powder as an absorber. The monitors can be set out in work spaces for 1-2 weeks and measured by AMS with regular samples. Frequent air changes help minimize aerosol contamination in many cases. Cross-contamination of samples can be minimized by using disposable plastic or glassware in the prep lab, isolating samples from the air when possible and using positive displacement pipettors. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Buchholz, BA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,L-397,7000 East Ave, Livermore, CA 94551 USA. RI Buchholz, Bruce/G-1356-2011; Freeman, Stewart/C-3290-2012 OI Freeman, Stewart/0000-0001-6148-3171 NR 7 TC 32 Z9 32 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 404 EP 408 DI 10.1016/S0168-583X(00)00142-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000070 ER PT J AU Kumamoto, Y Honda, MC Murata, A Harada, N Kusakabe, M Hayashi, K Kisen, N Katagiri, M Nakao, K Southon, JR AF Kumamoto, Y Honda, MC Murata, A Harada, N Kusakabe, M Hayashi, K Kisen, N Katagiri, M Nakao, K Southon, JR TI Distribution of radiocarbon in the western North Pacific: Preliminary results from MR97-02 cruise in 1997 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE radiocarbon; western North Pacific; North Pacific intermediate water ID INTERMEDIATE WATER; OCEAN AB In the transition area between the subarctic and subtropical regions in the western North Pacific, vertical distributions of radiocarbon at seven stations were clarified by AMS radiocarbon measurement in 1997. The radiocarbon in intermediate water at those stations indicate (1) direct ventilation of upper intermediate water above 26.6 sigma (theta) surface and (2) no temporal increment of radiocarbon in the transition area during the last two decades. These results positively suggest that the North Pacific intermediate water is formed in the transition area in the western North Pacific. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Japan Marine Sci & Technol Ctr, Ocean Res Dept, Yokosuka, Kanagawa 2370061, Japan. Marine Works Japan Co Ltd, Yokohama, Kanagawa, Japan. Kansai Environm Engn Ctr Co Ltd, Osaka, Japan. Univ Calif Lawrence Livermore Natl Lab, Ctr AMS, Livermore, CA 94550 USA. RP Kumamoto, Y (reprint author), Japan Marine Sci & Technol Ctr, Ocean Res Dept, Natsushima Cho 2-15, Yokosuka, Kanagawa 2370061, Japan. EM kumamoto@jamstec.go.jp NR 12 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 495 EP 500 DI 10.1016/S0168-583X(00)00207-X PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000086 ER PT J AU Galindo-Uribarri, A del Campo, JG Beene, JR Gross, CJ Liang, JF Paul, SD Shapira, D Stracener, DW Varner, RL Chavez, E Huerta, A Ortiz, ME Padilla, E Pascual, S AF Galindo-Uribarri, A del Campo, JG Beene, JR Gross, CJ Liang, JF Paul, SD Shapira, D Stracener, DW Varner, RL Chavez, E Huerta, A Ortiz, ME Padilla, E Pascual, S TI Study of resonant reactions with radioactive ion beams SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE radioactive ion beams; resonance scattering; silicon microstrip detectors ID SCATTERING; TARGETS AB A fast and efficient method to study (p,p) and (p,alpha) resonances with radioactive beams in inverse kinematics is described. It is based on the use of thick targets and large area double-sided silicon strip detectors (DSSDs) to detect the recoiling light-charged particles and to determine precisely their scattering angle. The first nuclear physics experiments with the technique have been performed recently at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge with stable beams of (17)O and radioactive beams of (17)F. Th, high-quality resonance measurements obtained demonstrate the capabilities of the technique. Pure (17)F beams from HRIBF were produced by fully stripping the ions and separating the interfering and more abundant (17)O ions by the beam transport system. The removal of interfering isobars is one of the various common challenges to both accelerator mass spectrometry (AMS) and radioactive ion beam (RIB) production. Experiments done with RIBs wilt benefit from the use of the most efficient techniques for production, isobar separation, transport and detection. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 04510, DF, Mexico. Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Mexico City 04510, DF, Mexico. RP Galindo-Uribarri, A (reprint author), Oak Ridge Natl Lab, Div Phys, POB 2008, Oak Ridge, TN 37831 USA. EM uribarri@mail.phy.ornl.gov NR 15 TC 30 Z9 30 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 647 EP 654 DI 10.1016/S0168-583X(00)00220-2 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000110 ER PT J AU Cecil, LD Welhan, JA Green, JR Grape, SK Sudicky, ER AF Cecil, LD Welhan, JA Green, JR Grape, SK Sudicky, ER TI Use of chlorine-36 to determine regional-scale aquifer dispersivity, eastern Snake River Plain aquifer, Idaho/USA SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE chlorine-36; groundwater; dispersivity ID MODELS AB Chlorine-36 (Cl-36) derived from processed nuclear waste that was disposed at the US Department of Energy's Idaho National Engineering and Environmental Laboratory (INEEL) through a deep injection well in 1958, was detected 24-28 yr later in groundwater monitoring wells approximately 26 km downgradient from the source. Groundwater samples covering the period 1966-1995 were selected from the US Geological Survey's archived-sample library at the INEEL and analyzed for Cl-36 by accelerator mass spectrometry (AMS). The smaller Cl-36 peak concentrations in water from the far-field monitoring wells relative to the input suggest that aquifer dispersivity may be large. However, the sharpness of the 1958 disposal peak of Cl-36 is matched by the measured Cl-36 concentrations in water from these wells. This implies that a small aquifer dispersivity may be attributed to preferential groundwater flowpaths. Assuming that tracer arrival times at monitoring wells are controlled by preferential flow, a 1-D system-response model was used to estimate dispersivity by comparing the shape of predicted Cl-36-concentration curves to the shape of Cl-36-concentration curves measured in water from these observation wells. The comparisons suggest that a 1-D dispersivity of 5 m provides the best fit to the tracer data. Previous work using a 2-D equivalent porous-media model concluded that longitudinal dispersivity (equivalent to 1-D dispersivity in our model) was 90 m (Ackerman, 1991). A 90 m dispersivity value eliminates the 1958 disposal peak in our model output curves. The implications of the arrival of Cl-36 at downgradient monitoring wells are important for three reasons: (1) the arrival times and associated Cl-36 concentrations provide quantitative constraints on residence times, velocities, and dispersivities in the aquifer; (2) they help to refine our working hypotheses of groundwater flow in this aquifer and (3) they may suggest a means of estimating the distribution of preferential flowpaths in the aquifer. (C) 2000 Elsevier Science B.V. All rights reserved. C1 US Geol Survey, Idaho Falls, ID 83402 USA. Idaho Geol Survey, Pocatello, ID USA. Univ Waterloo, Waterloo, ON N2L 3G1, Canada. RP Cecil, LD (reprint author), US Geol Survey, Suite C,900 N Skyline Dr, Idaho Falls, ID 83402 USA. NR 14 TC 6 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 679 EP 687 DI 10.1016/S0168-583X(00)00216-0 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000115 ER PT J AU Paul, M Berkovits, D Ahmad, I Borasi, F Caggiano, J Davids, CN Greene, JP Harss, B Heinz, A Henderson, DJ Henning, W Jiang, CL Pardo, RC Rehm, KE Rejoub, R Seweryniak, D Sonzogni, A Uusitalo, J Vondrasek, R AF Paul, M Berkovits, D Ahmad, I Borasi, F Caggiano, J Davids, CN Greene, JP Harss, B Heinz, A Henderson, DJ Henning, W Jiang, CL Pardo, RC Rehm, KE Rejoub, R Seweryniak, D Sonzogni, A Uusitalo, J Vondrasek, R TI AMS of heavy elements with an ECR ion source and the ATLAS linear accelerator SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA ID MASS-SPECTROMETRY AB Detection of heavy elements by accelerator mass spectrometry with the electron cyclotron resonance ion source, Argonne linear accelerator and fragment mass analyzer (ECRIS-ATLAS-FMA) system has been developed. The use of the ECR-ATLAS system for AMS of heavy elements has two interesting features: (i) the efficient production of high-charge state ions in the ECR source ensures the elimination of molecular ions at the source stage, a highly attractive feature for any mass-spectrometric use not exploited so far; (ii) the linear acceleration based on velocity matching and the beam transport system act as a powerful mass filter for background suppression. We have shown that our system reaches an abundance sensitivity of 1 x 10(-14) for Pb isotopes. The U-236 detection sensitivity is U-236/U greater than or similar to 1 x 10(-12), limited mainly by the ion source output. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. Soreq NRC, IL-81800 Yavne, Israel. Argonne Natl Lab, Argonne, IL 60439 USA. RP Paul, M (reprint author), Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. RI Heinz, Andreas/E-3191-2014 NR 14 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 688 EP 692 DI 10.1016/S0168-583X(00)00279-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000116 ER PT J AU McAninch, JE Hamilton, TF Brown, TA Jokela, TA Knezovich, JP Ognibene, TJ Proctor, ID Roberts, ML Sideras-Haddad, E Southon, JR Vogel, JS AF McAninch, JE Hamilton, TF Brown, TA Jokela, TA Knezovich, JP Ognibene, TJ Proctor, ID Roberts, ML Sideras-Haddad, E Southon, JR Vogel, JS TI Plutonium measurements by accelerator mass spectrometry at LLNL SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE plutonium; actinides; actinide elements; radiochemistry; plutonium bioassay; trace detection; accelerator mass spectrometry (AMS) ID FISSION-TRACK ANALYSIS; ENVIRONMENTAL-SAMPLES; ICP-MS; PU-239; CHROMATOGRAPHY; POPULATION; ACTINIDES; ISOTOPES; ELEMENTS; RONGELAP AB Mass spectrometric methods provide sensitive, routine, and cost-effective analyses of long-lived radionuclides. Here we report on the status of work at Lawrence Livermore National Laboratory (LLNL) to develop a capability for actinide measurements by accelerator mass spectrometry (AMS) to take advantage of the high potential of AMS for rejection of interferences. This work demonstrates that the LLNL AMS spectrometer is well-suited for providing high sensitivity, robust, high throughput measurements of plutonium concentrations and isotope ratios. Present backgrounds are similar to2 x 10(7) atoms per sample for environmental samples prepared using standard alpha spectrometry protocols. Recent measurements of Pu239+240 and Pu-241 activities and Pu-240/Pu-239 isotope ratios in IAEA reference materials agree well with IAEA reference values and with alpha spectrometry and recently published inductively coupled plasma-mass spectrometry (ICP-MS) results. Ongoing upgrades of the AMS spectrometer are expected to reduce backgrounds below 1 x 10(6) atoms per sample while allowing simplifications of the sample preparation chemistry. These simplifications will lead to lower per-sample costs, higher throughput, faster turn around and, ultimately, to larger and more robust data sets. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessment Div, Livermore, CA USA. Univ Witwatersrand, Schonland Res Ctr Nucl Sci, ZA-2050 Witwatersrand, South Africa. RP McAninch, JE (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,L-397, Livermore, CA 94551 USA. NR 45 TC 32 Z9 33 U1 2 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 711 EP 716 DI 10.1016/S0168-583X(00)00091-4 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000119 ER PT J AU Reedy, RC AF Reedy, RC TI Predicting the production rates of cosmogenic nuclides SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE cosmogenic nuclides; production rates; cross sections; nuclear reactions; numerical simulations ID CROSS-SECTIONS; STONY METEOROIDS; IRON-METEORITES; ENERGY PROTONS; DEPTH PROFILE; BE-10; SYSTEMATICS; SIMULATION; TARGETS; MATTER AB The determination and some uses of production rates of cosmogenic nuclides are reviewed. Emphasis is on work done since 1993 for long-lived cosmogenic radionuclides in extraterrestrial matter. Several Monte Carlo computer codes are being used to numerically simulate the interactions and transport of cosmic-ray particles. Thin- and thick-target irradiations have been done with protons to determine reaction cross sections and to experimentally simulate cosmic-ray bombardments. Cross sections for some neutron-induced reactions are being measured or inferred from thick-target irradiations. Some other works involving cosmogenic-nuclide production rates are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Reedy, RC (reprint author), Los Alamos Natl Lab, Mail Stop D436, Los Alamos, NM 87545 USA. EM rreedy@lanl.gov OI Reedy, Robert/0000-0002-2189-1303 NR 35 TC 7 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 782 EP 785 DI 10.1016/S0168-583X(00)00107-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000132 ER PT J AU Green, JR Cecil, LD Synal, HA Kreutz, KJ Wake, CP Naftz, DL Frape, SK AF Green, JR Cecil, LD Synal, HA Kreutz, KJ Wake, CP Naftz, DL Frape, SK TI Chlorine-36 and cesium-137 in ice-core samples from mid-latitude glacial sites in the Northern Hemisphere SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE chlorine-36; cesium-137; glaciology; radioactive fallout ID AMERICA AB Chlorine-36 (Cl-36) concentrations, Cl-36/Cl ratios, and Cl-36 fluxes in ice-core samples collected from the Upper Fremont Glacier (UFG) in the Wind River Mountain Range, Wyoming, United States and the Nangpai Gosum Glacier (NGG) in the Himalayan Mountains, Nepal, were determined and compared with published results from the Dye-3 ice-core drilling site on the Greenland Ice Sheet. Cesium-137 (Cs-137) concentrations in the NGG also were determined. The background fluxes for Cl-36 for each glacial site were similar: (1.6 +/- 0.3) x 10(-2) atoms/cm(2) s for the UFG samples, (0.7 +/- 0.1) x 10(-2) atoms/cm(2) s for the NGG samples, and (0.4 +/- 0.1) x 10(-2) atoms/cm(2) s for the Dye-3 samples. The Cl-36 fluxes in ice that was deposited as snow during peak atmospheric nuclear weapon test (1957-1958) were (33 +/- 1) x 10(-2) atoms/cm(2) s for the UFG site, (291 +/- 3) x 10(-2) atoms/cm(2) s for the NGG site, and (124 +/- 5) x 10(-2) atoms/cm(2) s for the Dye-3 site. A weapon test period Cs-137 concentration of 0.79 +/- 0.05 Bq/kg in the NGG ice core also was detected in the same section of ice that contained the largest Cl-36 concentration. (C) 2000 Elsevier Science B.V. All rights reserved. C1 US Geol Survey, Idaho Falls, ID 83402 USA. Paul Scherrer Inst, CH-8048 Zurich, Switzerland. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Univ New Hampshire, Durham, NH 03824 USA. US Geol Survey, Salt Lake City, UT USA. Univ Waterloo, Waterloo, ON N2L 3G1, Canada. RP Cecil, LD (reprint author), US Geol Survey, Suite C,900 N Skyline Dr, Idaho Falls, ID 83402 USA. RI Wake, Cameron/G-8114-2014; OI Wake, Cameron/0000-0002-5961-5902 NR 6 TC 3 Z9 3 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 812 EP 816 DI 10.1016/S0168-583X(00)00273-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000138 ER PT J AU Vogel, JS AF Vogel, JS TI Accelerator mass spectrometry for human biochemistry: The practice and the potential SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE accelerator mass spectrometry; biochemistry; nutrition; human; isotope; C-14; radiocarbon ID BIOMEDICAL APPLICATIONS; ATRAZINE METABOLITES; BONE-RESORPTION; HUMAN URINE; FOLIC-ACID; TRACER; EXPOSURE; ALUMINUM; DNA; LEVEL AB Isotopic labels are a primary tool for tracing chemicals in natural systems. Accelerator mass spectrometry (AMS) quantities long-lived isotopes that can be used in safe, sensitive and precise biochemical research with human participants. AMS could reduce the use of animals in biochemical research and remove the uncertain extrapolations from animal models to humans. Animal data seldom represent the sort of variability expected in a human population. People, knowingly or not, routinely expose themselves to radiation risks much greater than AMS-based biochemical research that traces mug/kg doses of chemicals containing tens of nCi of C-14 for as long as 7 months. AMS is applied to research in toxicology, pharmacology and nutrition. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. Univ Calif Davis, Dept Nutr, Davis, CA 95616 USA. RP Vogel, JS (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, 7000 East Ave L397, Livermore, CA 94551 USA. NR 28 TC 16 Z9 16 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 884 EP 891 DI 10.1016/S0168-583X(00)00235-4 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000149 ER PT J AU Buchholz, BA Dueker, SR Lin, YM Clifford, AJ Vogel, JS AF Buchholz, BA Dueker, SR Lin, YM Clifford, AJ Vogel, JS TI Methods and applications of HPLC-AMS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE HPLC; AMS; pharmacokinetics; physiological dose; metabolism AB Pharmacokinetics of physiologic doses of nutrients, pesticides, and herbicides can easily be traced in humans using a C-14-labeled compound. Basic kinetics can be monitored in blood or urine by measuring the elevation in the C-14 content above the control predose tissue and converting to equivalents of the parent compound. High performance liquid chromatography (HPLC) is an excellent method for the chemical separation of complex mixtures whose profiles afford estimation of biochemical pathways of metabolism. Compounds elute from the HPLC systems with characteristic retention times and can be collected in fractions that can then be graphitized for AMS measurement. Unknowns are tentatively identified by co-elution with known standards and chemical tests that reveal functional groupings. Metabolites are quantified with the C-14 signal. Thoroughly accounting for the carbon inventory in the LC solvents, ion-pairing agents, samples, and carriers adds some complexity to the analysis. In most cases the total carbon inventory is dominated by carrier. Baseline background and stability need to be carefully monitored. Limits of quantitation near 10 amol of C-14 per HPLC fraction are typically achieved. Baselines are maintained by limiting injected 14C activity <0.17 Bq (4.5 pCi) on the HPLC column. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. Univ Calif Davis, Dept Nutr, Davis, CA 95616 USA. RP Buchholz, BA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, POB 808,7000 East Ave,L-397, Livermore, CA 94551 USA. RI Buchholz, Bruce/G-1356-2011 NR 5 TC 10 Z9 11 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 910 EP 914 DI 10.1016/S0168-583X(00)00141-5 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000153 ER PT J AU Freeman, SPHT Beck, B Bierman, JM Caffee, MW Heaney, RP Holloway, L Marcus, R Southon, JR Vogel, JS AF Freeman, SPHT Beck, B Bierman, JM Caffee, MW Heaney, RP Holloway, L Marcus, R Southon, JR Vogel, JS TI The study of skeletal calcium metabolism with Ca-41 and Ca-45 SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE AMS; Ca-41; calcium; isotope; bone; resorption ID BONE TURNOVER AB The living skeleton can be labeled for life by the administration of radiologically trivial amounts of Ca-41 tracer. After initial elimination of tracer from the readily exchangeable calcium pools subsequent skeletal calcium turnover maintains and modulates the urine Ca-41 content. Uniquely, bone calcium metabolism may then be studied with tracer in near equilibrium with the body's calcium and resorbing calcium directly measured by accelerator mass spectrometry (AMS) of excreta. Our experiments with 25 Ca-41 labeled subjects demonstrate excellent diurnal stability and remarkable response to intervention of the urine signal. Thus the tracer method may prove a competitive means of measuring the effects of antiresorptive osteoporosis treatments, for therapy development or even clinical monitoring. Novel studies of long-term skeletal evolution are also possible. We realize that routinely administered short-lived calcium radiotracers contain Ca-41 impurities and that thousands of experimental participants have been historically inadvertently Ca-41 labeled. The Ca-41 urine index might now rapidly further be characterized by contemporary measurements of these onetime subjects, and with their by now thoroughly skeleton-equilibrated tracer they might be ideal participants in other new experiments. We are also investigating Ca-45 AMS. It may prove preferable to label the skeleton with this radiotracer already familiar to bioscientists, but new to AMS, (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr AMS, Livermore, CA USA. Stanford Univ, Sch Med, Stanford, CA 94305 USA. Creighton Univ, Osteoporosis Res Ctr, Omaha, NE 68178 USA. RP Freeman, SPHT (reprint author), Scottish Univ Environm Res Ctr, Scottish Enterprise Technol Pk, E Kilbride Q75 0QF, Lanark, Scotland. RI Beck, Belinda/B-9079-2008; Caffee, Marc/K-7025-2015; Freeman, Stewart/C-3290-2012 OI Beck, Belinda/0000-0003-1295-6395; Caffee, Marc/0000-0002-6846-8967; Freeman, Stewart/0000-0001-6148-3171 NR 5 TC 33 Z9 37 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 930 EP 933 DI 10.1016/S0168-583X(00)00341-4 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000157 ER PT J AU Rugel, G Faestermann, T Knie, K Korschinek, G Marchetti, AA McAninch, JE Ruhm, W Straume, T Wallner, C AF Rugel, G Faestermann, T Knie, K Korschinek, G Marchetti, AA McAninch, JE Ruhm, W Straume, T Wallner, C TI Accelerator mass spectrometry of Ni-63 using a gas-filled magnet at the Munich Tandem Laboratory SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 8th International Conference on Accelerator Mass Spectrometry CY SEP 06-10, 1999 CL VIENNA, AUSTRIA DE accelerator mass spectrometry; Ni-63; Hiroshima; gas-filled magnet ID HIROSHIMA ATOMIC-BOMB; FAST-NEUTRON FLUENCE; AMS AB The detection of Ni-63 (T-1/2 = 100.1 yr) by means of accelerator mass spectrometry (AMS) using a gas-filled magnet (GFM) is described. The experimental setup includes a dedicated ion source, a 14 MV MP tandem, a GFM and a multianode ionization chamber. First results indicate a background level of Ni-63/Ni ratios as low as 2 x 10(-14). This sensitivity will allow - for the first time ever - to detect Ni-63 induced by fast neutrons in copper samples from Hiroshima and Nagasaki, even for distances beyond 1500 m from the hypocenters. Thus, it will be possible to reconstruct experimentally the neutron doses of the A-bomb survivors from Hiroshima and Nagasaki. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tech Univ Munich, Fak Phys, D-85747 Garching, Germany. Univ Munich, Inst Strahlenbiol, D-80336 Munich, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Utah, Salt Lake City, UT 84108 USA. RP Rugel, G (reprint author), Beschleunigerlabor Forschungslande Garching, D-85748 Garching, Germany. OI Faestermann, Thomas/0000-0002-6603-8787 NR 13 TC 15 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 172 BP 934 EP 938 DI 10.1016/S0168-583X(00)00108-7 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 372JR UT WOS:000165231000158 ER PT J AU Alton, GD Liu, Y Williams, C Murray, SN AF Alton, GD Liu, Y Williams, C Murray, SN TI A new concept kinetic-ejection negative-ion source for rib generation SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article DE negative ions; ion source; radioactive isotopes; cesium-sputter; fluorine ions; ionization efficiency; radioactive ion beams ID BEAM AB Chemically active radioactive species are often released from target-materials in a variety of molecular forms. For example, F-17, is principally released from Al2O3 target-material as (AlF)-F-17. Because of the low probability of simultaneously dissociating such molecular carriers and efficiently ionizing their atomic constituents with conventional hot-cathode, electron-impact ion sources, species of interest are often distributed in several mass channels in the form of molecular side-band beams. Consequently, beam intensities of the desired radioactive species are diluted. The sputter negative-ion beam generation technique is particularly effective for simultaneously dissociating molecular carriers and efficiently ionizing highly electronegative atomic constituents. Therefore, a new concept kinetic-ejection negative-ion source (KENIS), based on this principle, was conceived to address this problem. The source has proven to be highly efficient for simultaneously dissociating and negatively ionizing sputter-ejected atomic fluorine from cesiated surfaces. The source has been successfully employed on-line to generate high intensity F-17(-) beams for use in the astrophysics research program at the Holifield Radioactive Ion Beam Facility (HRIBF) using the O-16(d,n)F-17 reaction. The mechanical design features, principles of operation, operational parameters, beam quality information (emittance data) and efficiencies for forming intense beams of F-17(-) during off-line and on-line operation of the source are presented in this report. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RP Alton, GD (reprint author), Oak Ridge Natl Lab, Div Phys, POB 2008, Oak Ridge, TN 37831 USA. NR 10 TC 14 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD OCT PY 2000 VL 170 IS 3-4 BP 515 EP 522 DI 10.1016/S0168-583X(00)00238-X PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 355MM UT WOS:000089389500027 ER PT J AU Logan, J AF Logan, J TI Graphical analysis of PET data applied to reversible and irreversible tracers SO NUCLEAR MEDICINE AND BIOLOGY LA English DT Article; Proceedings Paper CT Meeting of the Quantitative Analysis of Tumor Biochemistry Using PET and SPECT CY NOV 18-19, 1999 CL BETHESDA, MARYLAND DE graphical analysis; compartmental modeling; distribution volume; influx constant ID POSITRON-EMISSION-TOMOGRAPHY; LIVING HUMAN-BRAIN; TIME UPTAKE DATA; PARKINSONS-DISEASE; TRANSFER CONSTANTS; C-11 RACLOPRIDE; BLOOD-FLOW; BINDING; DOPAMINE; RECEPTORS AB The differential equations of compartmental analysis form the basis of the models describing the uptake of tracers used in imaging studies. Graphical analyses convert the model equations into linear plots, the slopes of which represent measures of tracer binding, The graphical methods are not dependent upon a particular model structure but the slopes can be related to combinations of the model parameters if a model structure is assumed, The input required is uptake data from a region of interest vs time and an input function that can either be plasma measurements or uptake data from a suitable reference region. Graphical methods can be applied to both reversible and irreversibly binding tracers. They provide considerable ease of computation compared to the optimization of individual model parameters in the solution of the differential equations generally used to describe the binding of tracers. Conditions under which the graphical techniques are applicable and st,me problems encountered in separating tracer delivery and binding are considered. Also the effect of noise can introduce a bias in the distribution volume which is the slope of the graphical analysis of reversible tracers. Smoothing techniques may minimize this problem and retain the model independence. In any case graphical techniques can provide insight into the binding kinetics of tracers in a visual way. NUCL MED BIOL 27;7:661-670, 2000. (C) 2000 Elsevier Science Inc, All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Logan, J (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. FU NINDS NIH HHS [NS15380] NR 28 TC 199 Z9 201 U1 2 U2 9 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0969-8051 J9 NUCL MED BIOL JI Nucl. Med. Biol. PD OCT PY 2000 VL 27 IS 7 BP 661 EP 670 DI 10.1016/S0969-8051(00)00137-2 PG 10 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 379AC UT WOS:000165617900006 PM 11091109 ER PT J AU Kiyo, Y Kodaira, J Morii, K Nasuno, T Parke, S AF Kiyo, Y Kodaira, J Morii, K Nasuno, T Parke, S TI The spin correlation in top quark production: QCD corrections vs anomalous couplings SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th Zeuthen Workshop on Elementary Particle Theory - Loops and Legs in Quantum Field Theory CY APR 09-14, 2000 CL BASTEI, GERMANY ID PAIR PRODUCTION; HEAVY QUARKS; COLLIDERS; DECAY; LEPTONS AB We discuss top quark production and its subsequent decay at lepton colliders including both QCD corrections and anomalous gamma /Z - t (t) over bar couplings. The off-diagonal spin basis for the top and anti-top quarks is shown to be useful to probe the anomalous couplings. C1 Hiroshima Univ, Dept Phys, Higashihiroshima 7398526, Japan. Fermi Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. RP Kiyo, Y (reprint author), Hiroshima Univ, Dept Phys, Higashihiroshima 7398526, Japan. NR 17 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD OCT PY 2000 VL 89 BP 37 EP 42 DI 10.1016/S0920-5632(00)00819-7 PG 6 WC Physics, Particles & Fields SC Physics GA 370PT UT WOS:000165132000006 ER PT J AU Melnikov, K van Ritbergen, T AF Melnikov, K van Ritbergen, T TI About the three-loop relation between the (MS)over-bar and the pole quark masses SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th Zeuthen Workshop on Elementary Particle Theory - Loops and Legs in Quantum Field Theory CY APR 09-14, 2000 CL BASTEI, GERMANY ID HEAVY-QUARK; PERTURBATION-THEORY; ORDER; QCD AB We give a brief overview of the recent analytical calculation of the relation between the (MS) over bar quark mass and the pole quark mass at the third order of Quantum Chromodynamics. Other new results for typical on-shell QCD quantities beyond two-loops are briefly discussed as well, such as a 3-loop result for the quark wave function renormalization factor Z(2) in the on-shell scheme. 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 27 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD OCT PY 2000 VL 89 BP 52 EP 57 DI 10.1016/S0920-5632(00)00822-7 PG 6 WC Physics, Particles & Fields SC Physics GA 370PT UT WOS:000165132000009 ER PT J AU Eaton, S Beard, C Ramsey, K Buksa, J Chidester, K AF Eaton, S Beard, C Ramsey, K Buksa, J Chidester, K TI Development of nonfertile and evolutionary mixed-oxide nuclear fuels for use in existing water reactors SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB Investigations of an advanced fuel form are currently under way. This new fuel form, referred to as evolutionary mixed oxide (EMOX), is a slight perturbation on standard mixed-oxide (MOX)fuel, and analyses show that it can be an effective plutonium management tool in existing light water reactors. The addition of a small fraction of calcia-stabilized zirconia to the uranium-plutonium oxide matrix allows for greater plutonium conversion while also providing a licensing path forward toward eventual implemetation of higher plutonium-destruction fuels. These fuels, referred to as nonfertile (NF)fuels, achieve their high destruction rates through the absence of uranium which breeds plutonium, in the fuel composition. Extensive calculations have been performed to assess the feasibility of incorporating the EMOX fuel form into existing pressurized water reactor systems, and the results are given in detail. Specifically, calculations have been made to determine the plutonium consumption achievable by the EMOX concept, and comparisons have been made of this performance to that of typical MOX and NF fuels. The results indicate that EMOX and NF fuels can provide flexibility with regard to controlling plutonium inventories in spent fuel. In addition, fabrication experiments have been conducted to determine the feasibility of fabricating suitable EMOX and NF fuels. NF and EMOX fuels have been fabricated using the solid-stare reaction method. Precursor powders were successfully blended and milled using a combination of ball milling and high-energy vibratory milling. Sintering data for EMOX fuel indicated that significant densification occurred at a temperature of 1700 degrees C. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Texas, Austin, TX 78712 USA. RP Eaton, S (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop K551, Los Alamos, NM 87545 USA. NR 10 TC 2 Z9 2 U1 1 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD OCT PY 2000 VL 136 IS 2 BP 151 EP 177 PG 27 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 358DX UT WOS:000089542900001 ER PT J AU Azmy, YY AF Azmy, YY TI Acceleration of multidimensional discrete ordinates methods via adjacent-cell preconditioners SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID DIFFUSION-SYNTHETIC ACCELERATION; TRANSPORT METHODS; EQUATIONS AB The adjacent-cell preconditioner (AP) formalism originally derived in slab geometry is extended to multidimensional Cartesian geometry for genetic fixed-weight, weighted diamond difference neutron transport methods, This is accomplished for the thick-cell regime (KAP) and thin-cell regime (NAP). A spectral analysis of the resulting acceleration schemes demonstrates their excellent spectral properties for model problem configurations, characterized bf a uniform mesh of infinite extent and homogeneous material composition each in its own cell-size regime. Thus, the spectral radius of KAP vanishes as the computational cell size approaches infinity but it exceeds unity for very thin cells, thereby implying instability In contrast, NAP is stable and robust for all cell sizes, but its spectral radius vanishes more slowly as the cell size increases. For this reason, and to avoid potential complication in the case of cells that are thin in one dimension and thick in another, NAP is adopted in the remainder of this work. The most important feature of AP for practical implementation in production level codes is that it is cell centered, reducing the size of the algebraic system comprising the acceleration stage compared to face-centered schemes. Boundary conditions for finite extent problems and a mixing formula across material and cell-size discontinuity are derived and used to implement NAP in a test rode, AHOT, and a production code, TORT. Numerical testing for algebraically linear iterative schemes for the cases embodied in Burre's Suite of Test Problems demonstrates the high efficiency of the new method in reducing the number of iterations required to achieve convergence, especially for optically thick cells where acceleration is most needed. Also, for algebraically nonlinear (adaptive) methods, AP generally performs better than the par tial current rebalance method in TORT and the diffusion synthetic acceleration method in TWODANT. Finally, application of the AP formalism to a simplified linear nodal (SLN) method similar, but not identical, to TORT's linear nodal option is shown to possess two eigenvalues that approach either one or infinity with increasing cell size regardless of the preconditioner parameters. This implies impossibility of unconditionally robust acceleration of SLN-type methods with cell-centered preconditioners that have a block-diffusion coupling stencil Edge-centered acceleration methods, or methods that do not require the linear moments of the flux to converge, might have an advantage in this regard but at a significant penalty to computational efficiency due to the larger system soh,ed or the inability to utilize the computed linear moments. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Oak Ridge Natl Lab, POB 2008,MS 6363, Oak Ridge, TN 37831 USA. EM azmyyy@ornl.gov NR 16 TC 4 Z9 4 U1 0 U2 0 PU AMER NUCLEAR SOC PI LA GRANGE PK PA 555 N KENSINGTON AVE, LA GRANGE PK, IL 60526 USA SN 0029-5639 EI 1943-748X J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD OCT PY 2000 VL 136 IS 2 BP 202 EP 226 PG 25 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 358DX UT WOS:000089542900003 ER PT J AU Carew, JF Hu, K Zamonsky, G AF Carew, JF Hu, K Zamonsky, G TI Uniform Gauss-weight quadratures for discrete ordinate transport calculations SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB Recently, a uniform equal-weight quadrature set, UEn, and a uniform Gauss-weight quadrature set, UG(n), have been derived. These quadratures have the advantage over the standard level-symmetric LQ(n) quadrature sets in that the weights are positive for all orders,and the transport solution may be systematically converged by increasing the order of the quadrature set. As the order of the quadrature is increased,the points approach a uniform continuous distribution on the unit sphere,and the quadrature is invariant with respect to spatial rotations. The numerical integrals converge for continuous functions as the order of the quadrature is increased. The numerical characteristics of the UEn quadrature set have been investigated previously. In this paper, numerical calculations are performed to evaluate the application of the UG(n) quadrature set in typical transport analyses. A series of DORT transport calculations of the >1-MeV neutron flux have been performed for a set of pressure-vessel fluence benchmark problems. These calculations employed the UG(n) (n = 8, 12, 16, 24, and 32) quadratures and indicate that the UG(n) solutions have converged to within similar to 0.25%. The converged UG(n) solutions are found to be comparable to the UEn results and are more accurate than the level-symmetric S-16 predictions. C1 Brookhaven Natl Lab, Dept Adv Technol, Energy & Nucl Technol Div, Upton, NY 11973 USA. RP Carew, JF (reprint author), Brookhaven Natl Lab, Dept Adv Technol, Energy & Nucl Technol Div, POB 5000, Upton, NY 11973 USA. NR 11 TC 1 Z9 1 U1 1 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD OCT PY 2000 VL 136 IS 2 BP 282 EP 293 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 358DX UT WOS:000089542900009 ER PT J AU Pasamehmetoglu, KO Willcutt, GJ Elson, JS Siebe, DA AF Pasamehmetoglu, KO Willcutt, GJ Elson, JS Siebe, DA TI Thermal-hydraulic design of the accelerator production of tritium tungsten neutron source SO NUCLEAR TECHNOLOGY LA English DT Article DE spallation target; thermal-hydraulic design; high-energy accelerator AB The thermal-hydraulic design of the accelerator production of tritium (APT) tungsten neutron source is presented. A carefully engineered thermal-hydraulic design is required to remove the deposited power effectively during normal operations and remove the decay power during plant shutdown and postulated accidents. For steady-state operations and operational and anticipated transients, the design criterion is to maintain single-phase flow conditions with a margin to onset of nucleate boiling. The margin is determined based on phenomenological and geometric uncertainties associated with the design. A large margin to thermal excursion limits, such as critical heat flux and onset of flow instability, also is maintained during normal operations. In general, a very robust thermal-hydraulic design can be accomplished using the traditional models and correlations available in the engineering literature. However, two issues require further attention: maintaining adequate flows in a parallel network of flow channels and minimizing the volume fraction of heavy water to maximize tritium production. The design uses ladderlike structures that contain clad tungsten cylinders in the rungs that have coolant supplied and removed by the vertical ladder rails. Because the power density drops in the beam direction, the thickness of the tungsten cylinders is increased with increasing beam penetration length. The cooling requirement is determined using a conservative criterion where the minimum wall subcooling inside the rungs is at least 40 degrees C and the minimum Reynolds number is 6000. Initial flow distribution tests were conducted with a full-scale model of an APT ladder assembly based on a preliminary design. Flow distributions can be made more even by using a larger riser than downcomer and also by increasing the flow resistance across each rung. The calculations discussed assume nominal dimensions, even though the power deposition and removal use a conservative approach. The effect of manufacturing tolerances will be investigated in future research. Also, the applicability of the critical heat flux and onset of flow instability models to small coolant channels is being verified experimentally. Further design optimization will be possible when these studies are completed. C1 Univ Calif Los Alamos Natl Lab, ATW Project, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Nucl Syst Design & Anal Grp, Los Alamos, NM 87545 USA. RP Pasamehmetoglu, KO (reprint author), Univ Calif Los Alamos Natl Lab, ATW Project, POB 1663, Los Alamos, NM 87545 USA. NR 14 TC 0 Z9 0 U1 1 U2 2 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 3 EP 14 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700002 ER PT J AU Venneri, F Williamson, MA Li, N Houts, MG Morley, RA Beller, DE Sailor, W Lawrence, G AF Venneri, F Williamson, MA Li, N Houts, MG Morley, RA Beller, DE Sailor, W Lawrence, G TI Disposition of nuclear waste using subcritical accelerator-driven systems: Technology choices and implementation scenarios SO NUCLEAR TECHNOLOGY LA English DT Article DE accelerator; transmutation; waste AB Los Alamos National Laboratory has led the development of accelerator-driven transmutation of waste (ATW) to provide an alternative technological solution to the disposition of nuclear waste. While ATW will not eliminate the need for a high-level waste repository, it offers a new technology option for altering the nature of nuclear waste and enhancing the capability of a repository. The basic concept of ATW focuses on reducing the time horizon for the radiological risk from hundreds of thousands of years to a few hundred years and on reducing the thermal loading. As such, ATW will greatly reduce the amount of transuranic elements that will be disposed of in a high-level waste repository The goal of the ATW nuclear subsystem is to produce three orders of magnitude reduction in the long-term radiotoxicity of the waste sent to a repository, including losses through processing. If the goal is met, the radiotoxicity of ATW treated waste after 300 yr would be less than that of untreated waste after 100 000 yr. These objectives can be achieved through the use of high neutron fluxes produced in accelerator-driven subcritical systems. While critical fission reactors can produce high neutron fluxes to destroy actinides and select fission products, the effectiveness of the destruction is limited by the criticality requirement Furthermore, a substantial amount of excess reactivity would have to be supplied initially and compensated for by control poisons. To overcome these intrinsic limitations, we searched for solutions in subcritical systems freed from the criticality requirement by taking advantage of the recent breakthroughs in accelerator technology and the release of liquid lead/bismuth nuclear coolant technology from Russia. The effort led to the selection of an accelerator-driven subcritical system that results in the destruction of the actinides and fission products of concern as well as permitting easy operational control through the external control of the neutron source. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Venneri, F (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 26 TC 6 Z9 6 U1 2 U2 4 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 15 EP 29 PG 15 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700003 ER PT J AU Gabriel, TA Barnes, JM Charlton, LA DiStefano, J Farrell, K Haines, J Johnson, JO Mansur, LK Pawel, SJ Siman-Tov, M Taleyarkhan, R Wendel, MW AF Gabriel, TA Barnes, JM Charlton, LA DiStefano, J Farrell, K Haines, J Johnson, JO Mansur, LK Pawel, SJ Siman-Tov, M Taleyarkhan, R Wendel, MW TI Target systems overview for the Spallation Neutron Source SO NUCLEAR TECHNOLOGY LA English DT Article DE neutron scattering; spallation sources; materials research AB The purpose and requirements of target systems as well as the technologies that are being utilized to design and build a state-of-the-art neutron spallation source, the Spallation Neutron Source, are discussed. Emphasis is given to the technology issues that present the greatest scientific challenges. The present facility configuration, ongoing analysis, and planned hardware research and development program are also described. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Lockheed Martin Energy Syst Inc, Oak Ridge, TN 37820 USA. RP Gabriel, TA (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. OI Rennich, Mark/0000-0001-6945-0075 NR 13 TC 1 Z9 1 U1 0 U2 1 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 49 EP 60 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700005 ER PT J AU Charlton, LA Barnes, JM Johnson, JO Gabriel, TA AF Charlton, LA Barnes, JM Johnson, JO Gabriel, TA TI Neutronic design studies for the Spallation Neutron Source SO NUCLEAR TECHNOLOGY LA English DT Article DE Spallation Neutron Source; neutronic optimization studies; Monte Carlo AB Neutronics analyses are now in progress to support initial selection of target system design features, materials, geometry, and component sizes for the proposed Spallation Neutron Source. Calculations have been performed to determine the neutron, proton, heavy-ion, and gamma-ray flux spectra as a function of time, energy, and space for the major components of the target station (target, moderators, reflectors, etc.). These analyses have also been performed to establish an initial set of performance characteristics for the neutron source. The methodology, reference performance characteristics, and results of initial optimization studies involving moderator poison plate location, target material performance, reflector performance, moderator position, and premoderator performance for the target system are presented. C1 Oak Ridge Natl Lab, Nucl Anal & Shielding Sect, Computat Phys & Engn Div, Appl Phys Grp, Oak Ridge, TN 37831 USA. RP Charlton, LA (reprint author), Oak Ridge Natl Lab, Nucl Anal & Shielding Sect, Computat Phys & Engn Div, Appl Phys Grp, POB 2008, Oak Ridge, TN 37831 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 94 EP 102 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700008 ER PT J AU Maloy, SA Sommer, WF James, MR Romero, TJ Lopez, MR Zimmermann, E Ledbetter, JM AF Maloy, SA Sommer, WF James, MR Romero, TJ Lopez, MR Zimmermann, E Ledbetter, JM TI The accelerator production of tritium materials test program SO NUCLEAR TECHNOLOGY LA English DT Article DE materials; irradiation; mechanical tests AB A materials qualification program has been developed to irradiate and test candidate materials (alloy 718, Type 316L, and Type 304L stainless steel, modified Fe9Cr-1Mo(T91), Al-6061-T6, and Al-5052-O) for use in the Accelerator Production of Tritium (APT) target and blanket. The irradiations were performed in prototypic proton and neutron spectra at prototypic temperatures (50 to 160 degrees C). The study used the 800-MeV, 1.0-mA proton accelerator at the Los Alamos Neutron Science Center, which produces a Gaussian beam with 2 sigma = 3 cm. The experiment geometry is arranged to contain near-prototypic modules of the tungsten neutron source and the lead and aluminum blanket as well as mechanical test specimens of candidate APT materials. The particle spectrum varies throughout the irradiation volume; specimens are exposed to protons and a variety of mixed proton and neutron spectra, depending on the specimen's position relative to the beam center. These specimens have been irradiated for >3600 h to a maximum proton fluence of 4 x 10(21) p/cm(2) in the center of the proton beam. Specimens will yield data on the effect of proton irradiation, to high dose, on material properties from tensile tests, three-point bend tests, fracture toughness tests, pressurized tubes, U-bend stress corrosion cracking specimens, corrosion measurements, and microstructural characterization using transmission electron microscopy specimens., Results from these studies are applicable to all spallation neutron sources now in operation and under consideration, including the Spallation Neutron Source, the European Spallation Source, and The Accelerator Transmutation of Waste project. C1 Univ Calif Los Alamos Natl Lab, APT TPO Grp, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, LANSCE, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, APT Mat Program, Los Alamos, NM 87545 USA. RP Maloy, SA (reprint author), Univ Calif Los Alamos Natl Lab, APT TPO Grp, Los Alamos, NM 87545 USA. RI Maloy, Stuart/A-8672-2009 OI Maloy, Stuart/0000-0001-8037-1319 NR 13 TC 7 Z9 7 U1 0 U2 4 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 103 EP 114 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700009 ER PT J AU Cappiello, MW Lisowski, PW AF Cappiello, MW Lisowski, PW TI Target/blanket design for the accelerator production of tritium plant SO NUCLEAR TECHNOLOGY LA English DT Article DE spallation neutron source; tritium; spallation physics AB The Accelerator Production of Tritium Target/Blanket (T/B) system is comprised of an assembly of tritium-producing modules supported by safety, heat removal, shielding, and retargeting systems. The T/B assembly produces tritium using a high-energy proton beam, a tungsten/lead spallation neutron source and Ne-3 gas us the tritium-producing feedstock. The supporting heat removal systems remove the heat deposited by the proton beam during both normal and off-normal conditions. The shielding protects workers from ionizing radiation, and the retargeting systems remove and replace components that have reached their end of life. All systems reside within the T/B building, which is located at the end of a linear accelerator. For the nominal production mode, protons are accelerated to an energy of 1030 MeV at a current of 100 mA and are directed onto the T/B assembly. The protons are expanded to a 0.19- x 1.9-m beam spot before striking a centrally located tungsten neutron source. A surrounding lead blanket produces additional neutrons from scattered high-energy particles. A total of 27 neutrons are produced per incident proton. Tritium is produced by neutron capture in He-3 gas that is contained in aluminum tubes throughout the blanket. The He-3/tritium mixture is removed on a semi-continuous basis for purification in an adjacent Tritium Separation Facility. Systems and components ave designed with safety as a primary consideration to minimize risk to the workers and the public. Materials and component designs were chosen based on the experiences of operating spallation neutron sources that have been designed and built for the neutron science community. An extensive engineering development and demonstration program provides detailed information for the completion of the design. C1 Univ Calif Los Alamos Natl Lab, APT Tech Proj Off, Los Alamos, NM 87545 USA. RP Cappiello, MW (reprint author), Univ Calif Los Alamos Natl Lab, APT Tech Proj Off, MS H816, Los Alamos, NM 87545 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 115 EP 127 PG 13 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700010 ER PT J AU Polkinghorne, ST Davis, CB McCracken, RT AF Polkinghorne, ST Davis, CB McCracken, RT TI Analysis of an advanced test reactor small-break loss-of-coolant accident with an engineered safety feature to automatically trip the primary coolant pumps SO NUCLEAR TECHNOLOGY LA English DT Article DE Advanced Test Reactor; small-break loss-of-coolant accident; RELAP5 AB A new engineered safety feature that automatically trips the primary coolant pumps following a low-pressure reactor scram was recently installed in the Advanced Test Reactor (ATR). The purpose of this engineered safety feature is to prevent the ATR's surge tank, which contains compressed air, from emptying during a small-break loss-of-coolant accident (SBLOCA). If the surge tank were to empty, the air introduced into the primary coolant loop could potentially cause the performance of the primary and/or emergency coolant pumps to degrade, thereby reducing cove thermal margins. Safety analysis performed with the RELAP5 thermal-hydraulic code and the SINDA thermal analyzer shows that adequate thermal margins ave maintained during an SBLOCA with the new engineered safety feature installed. The analysis also shows that the surge tank will not empty during an,SBLOCA even if one of the primary coolant pumps fails to trip. C1 Idaho Natl Engn & Environm Lab, Bechtel BWXT Idaho, LLC, Thermal Hydraul Code Dev & Applicat Grp, Idaho Falls, ID 83415 USA. RP Polkinghorne, ST (reprint author), Idaho Natl Engn & Environm Lab, Bechtel BWXT Idaho, LLC, Thermal Hydraul Code Dev & Applicat Grp, POB 1625, Idaho Falls, ID 83415 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD OCT PY 2000 VL 132 IS 1 BP 167 EP 178 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 359FK UT WOS:000089600700013 ER PT J AU Krauss, RM AF Krauss, RM TI Genetic and metabolic determinants of atherogenic lipoprotein phenotype. SO OBESITY RESEARCH LA English DT Meeting Abstract C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NORTH AMER ASSOC STUDY OBESITY PI ROCHESTER PA C/O DR MICHAEL JENSEN, MAYO MEDICAL CENTER, MAYO CLIN 200 FIRST ST, SW, ROCHESTER, MN 55905 USA SN 1071-7323 J9 OBES RES JI Obes. Res. PD OCT PY 2000 VL 8 SU 1 MA I28 BP 4S EP 4S PG 1 WC Endocrinology & Metabolism; Nutrition & Dietetics SC Endocrinology & Metabolism; Nutrition & Dietetics GA 364DE UT WOS:000089876100016 ER PT J AU West, D Dhar, M Webb, L Smith, L Hauser, L Johnson, D AF West, D Dhar, M Webb, L Smith, L Hauser, L Johnson, D TI A heterozygous deletion of a novel ATPase gene on mouse chromosome 7 increases body fat. SO OBESITY RESEARCH LA English DT Meeting Abstract C1 Pfizer Global Res & Dev Alameda Labs, Alameda, CA USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. RI Hauser, Loren/H-3881-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU NORTH AMER ASSOC STUDY OBESITY PI ROCHESTER PA C/O DR MICHAEL JENSEN, MAYO MEDICAL CENTER, MAYO CLIN 200 FIRST ST, SW, ROCHESTER, MN 55905 USA SN 1071-7323 J9 OBES RES JI Obes. Res. PD OCT PY 2000 VL 8 SU 1 MA O184 BP 59S EP 59S PG 1 WC Endocrinology & Metabolism; Nutrition & Dietetics SC Endocrinology & Metabolism; Nutrition & Dietetics GA 364DE UT WOS:000089876100236 ER PT J AU Howells, MR Cambie, D Duarte, RM Irick, S MacDowell, AA Padmore, HA Renner, TR Rah, S Sandler, R AF Howells, MR Cambie, D Duarte, RM Irick, S MacDowell, AA Padmore, HA Renner, TR Rah, S Sandler, R TI Theory and practice of elliptically bent x-ray mirrors SO OPTICAL ENGINEERING LA English DT Article DE synchrotron radiation; elliptical cylinder; mirror; adaptive; x-ray; microprobe ID SYNCHROTRON RADIATION; DESIGN CONSIDERATIONS; FOCUSING OPTICS; PERFORMANCE; MONOCHROMATOR; MICROPROBE; CURVATURE; CRYSTALS; PROGRESS; SCHEMES AB We report the results of our research and development in techniques for producing elliptical x-ray mirrors by controlled bending of a flat substrate. We review the theory and technique of mirror bending with emphasis on the optical engineering issues and describe our design concepts for both metal and ceramic mirrors. We provide analysis of the various classes of error that must be addressed to obtain a high quality elliptical surface and a correspondingly fine focus of the x-ray beam. We describe particular mirrors that have been built, using these techniques, to meet the requirements of the scientific program at the Advanced Light Source at Lawrence Berkeley National Laboratory. For these examples, we show optical metrology results indicating the achievement of surface accuracy values around and, in some cases, below 1 mu rad as well as x-ray measurements showing submicrometer focal spots. (C) 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)01410-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Pohang Univ Sci & Technol, Pohang 790784, South Korea. RP Howells, MR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. NR 51 TC 61 Z9 61 U1 3 U2 8 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD OCT PY 2000 VL 39 IS 10 BP 2748 EP 2762 DI 10.1117/1.1289879 PG 15 WC Optics SC Optics GA 365MA UT WOS:000089954000022 ER PT J AU Hammersley, G Hackel, LA Harris, F AF Hammersley, G Hackel, LA Harris, F TI Surface prestressing to improve fatigue strength of components by laser shot peening SO OPTICS AND LASERS IN ENGINEERING LA English DT Article AB Laser shot peening has been developed as a surface treatment to metals, It has been shown to induce surface residual stresses comparable to those achieved by conventional shot peening, but to much greater depths, The laser technology employed is described and some test results are presented. (C) 2001 Elsevier Science Ltd. All rights reserved. C1 Met Improvement Co Inc, Derby DE24 8ST, England. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Met Improvement Co Inc, Rocklin, CA 95677 USA. RP Hammersley, G (reprint author), Met Improvement Co Inc, Ascot Dr, Derby DE24 8ST, England. NR 7 TC 80 Z9 87 U1 5 U2 19 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0143-8166 J9 OPT LASER ENG JI Opt. Lasers Eng. PD OCT-DEC PY 2000 VL 34 IS 4-6 BP 327 EP 337 DI 10.1016/S0143-8166(00)00083-X PG 11 WC Optics SC Optics GA 409BE UT WOS:000167364000009 ER PT J AU Leyens, C Wright, IG Pint, BA AF Leyens, C Wright, IG Pint, BA TI Effect of experimental procedures on the cyclic, hot-corrosion behavior of NiCoCrAlY-type bondcoat alloys SO OXIDATION OF METALS LA English DT Article DE hot-corrosion testing; NiCoCrAlY-type bond coats; contaminant flux rate; biomass fuels AB A simplified test procedure was established to assess the hot-corrosion behavior of MCrAlY-type nickel-base alloys under the influence of molten sodium sulfate as well as sodium sulfate/potassium sulfate salt blends. Salt-coated specimens were exposed to 1-hr thermal cycles at 950 degrees C in flowing oxygen for rip to 500 cycles. Mass-change data of the specimens revealed a significant dependence of the corrosion attack not only on the average contaminant flux: rate, as expected but also on the initial amount of salt deposited during each recoating cycle. Furthermore, deposit removal before salt recoating markedly influenced the corrosion attack of the alloys. This was apparently related to changes in salt chemistry by the dissolution of elements such as Cr from the alloy, which can shift the basicity of the salt and thus affect the extent of attack. Substituting Na for K in sodium sulfate/potassium sulfate salt blends generally resulted in decreased attack. For K-containing salt deposits, increasing the gross amount of alkali compared to sulfur resulted in increased sample Ir,eight losses due to scale spallation. In contrast, decreasing the amount of sulfur in such deposits which contained exclusively Na as the alkali resulted in a significantly reduced corrosion attack compared to stoichiometric sodium sulfate. C1 DLR, German Aerosp Ctr, Mat Res Inst, D-51170 Cologne, Germany. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Leyens, C (reprint author), DLR, German Aerosp Ctr, Mat Res Inst, D-51170 Cologne, Germany. EM christoph.leyens@dlr.de RI Wright, Ian/A-8300-2008; Pint, Bruce/A-8435-2008 OI Pint, Bruce/0000-0002-9165-3335 NR 16 TC 12 Z9 12 U1 0 U2 8 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0030-770X J9 OXID MET JI Oxid. Met. PD OCT PY 2000 VL 54 IS 3-4 BP 255 EP 276 DI 10.1023/A:1004698211940 PG 22 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 345DF UT WOS:000088799600004 ER PT J AU Bonnet, R Loubradou, M Dahmen, U AF Bonnet, R Loubradou, M Dahmen, U TI Atomic scale observation of the displacement fields generated by the intrinsic defects of {111}Ni3Al/(010) Ni3Nb close-packed interfaces SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID TRANSMISSION ELECTRON-MICROSCOPY; HIGH-RESOLUTION; ELASTIC FIELDS; DISLOCATIONS; ALLOY; BOUNDARY; LEDGE; STEPS AB The deformation generated by the intrinsic structure of facetted close-packed (11(1) over bar)Ni3Al//(010)Ni3Nb interfaces has been observed by high resolution electron microscopy. The interfaces separate Ni3Al (gamma') and Ni3Nb (delta) lamellae of a directionally solidified eutectic alloy. Three typical interfacial regions, I, II and III, have been examined. In region I a series of ten consecutive linear singularities has been analysed. Six of them, denoted A-F, have different core structures. They accommodate fully or partly the 2.1% length misfit according to the sequence denoted A-A-A-B-C-A-D-E-A-F. Of these singularities, A, B and C are dislocation ledges, whereas D and E are linked to a triple node junction involving gamma', delta, and an interfacial gamma' nanotwin. F limits an interfacial fault. Three types of Burgers vector content have been found (relative to the yl lattice): (i) 90 degrees, (1/6)[(112) over bar], for A, D E, F; (ii) 30 degrees, (1/6)[<(2)over bar 1(1)over bar>], for B; and (iii) 60 degrees, (1/6)[<(41)over bar>1] or (1/6)[<(14)over bar>1], for C. This latter contributes to accommodating an angular misfit. Only the 90 degrees Burgers vector content belongs to the gamma'-DSC lattice. It is inferred that the observed heterointerface consists of at least four different interfacial regions with different energies. In regions II and III the heterointerfaces exhibit other complex atomic structures involving gamma' interfacial Sigma 3 nanotwins. In region II a linear singularity linked to a triple node junction has a Burgers vector content of (1/2)(110), and accommodates partly an angular misfit. In region III three consecutive linear singularities have the same 90 degrees Burgers vector content, despite quite different environments. One of them interacts with a nearby 60 degrees gamma' superpartial so that the total dislocation content is (1/6)[<2(15)over bar>] or (1/6)[(1) over bar 2 (5) over bar]. It is concluded that the determination of the linear singularity structures at close-packed heterointerfaces is a more subtle and intricate question than apparently has been realized so far. C1 Ecole Natl Super Electrochim & Electrome Grenoble, Inst Natl Polytech Grenoble, LTPCM, UMR 5614, F-38402 St Martin Dheres, France. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, NCEM, Berkeley, CA 94720 USA. RP Bonnet, R (reprint author), Ecole Natl Super Electrochim & Electrome Grenoble, Inst Natl Polytech Grenoble, LTPCM, UMR 5614, Domaine Univ,BP 75, F-38402 St Martin Dheres, France. EM rbonnet@ltpcm.inpg.fr NR 51 TC 9 Z9 9 U1 1 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD OCT PY 2000 VL 80 IS 10 BP 2233 EP 2256 PG 24 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 361ZM UT WOS:000089754200002 ER PT J AU Ochs, T Elsasser, C Mrovec, M Vitek, V Belak, J Moriarty, JA AF Ochs, T Elsasser, C Mrovec, M Vitek, V Belak, J Moriarty, JA TI Symmetrical tilt grain boundaries in bcc transition metals: comparison of semiempirical with ab-initio total-energy calculations SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID GROUND-STATE PROPERTIES; BOND-ORDER POTENTIALS; TIGHT-BINDING METHODS; EMBEDDED-ATOM METHOD; ATOMISTIC SIMULATIONS; SCREW DISLOCATIONS; BODY POTENTIALS; ANGULAR FORCES; MOLYBDENUM; MO AB Five different semiempirical total-energy methods, provided in the literature and applicable for atomistic simulations of extended defects in bce transition metals, are investigated in a comparative study. The comparison is made with recent theoretical ab-initio (local-density-functional theory) and experimental (high-resolution transmission electron microscopy) studies for the specific case of the Sigma = 5, (310)[001] symmetrical tilt grain boundaries (Sigma = 5 STGBs) in Nb and Mo. The considered semiempirical real-space approaches based on different approximations of the tight-binding and related methods are the Finnis-Sinclair central-force potentials, non-central-force bond-order potentials recently advanced by Pettifor and co-workers, and non-central-force potentials based on the model-generalized pseudopotential theory of Moriarty. As semiempirical reciprocal-space methods, a very simple d-basis tight-binding model by Paxton and an elaborate environment dependent spd-basis orthogonal tight-binding model by Haas ct al. are included in the analysis. The virtues and deficiencies of these models in their ability to predict the translation states and interfacial energies of the Sigma = 5 STGB are discussed. C1 Max Planck Inst Met Res, D-70174 Stuttgart, Germany. Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA. Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA 94550 USA. RP Max Planck Inst Met Res, Seestr 92, D-70174 Stuttgart, Germany. EM elsae@marvin.mpi-stuttgart.mpg.de RI Mrovec, Matous/C-1315-2009 OI Mrovec, Matous/0000-0001-8216-2254 NR 61 TC 27 Z9 28 U1 1 U2 12 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD OCT PY 2000 VL 80 IS 10 BP 2405 EP 2423 PG 19 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 361ZM UT WOS:000089754200012 ER PT J AU Lu, G Kioussis, N Bulatov, VV Kaxiras, E AF Lu, G Kioussis, N Bulatov, VV Kaxiras, E TI The Peierls-Nabarro model revisited SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID FIRST-PRINCIPLES; DISLOCATIONS; FORMULATION; STRESSES AB We re-examine two important issues within the Peierls- Nabarro model, which are critical in obtaining accurate values for the Peierls stress. The first is related to the sampling scheme (double versus single counting) of the misfit energy across the glide plane and the second is the effect of atomic relaxation on the Peierls stress. We argue that the double-counting scheme is physically more appropriate. An analytical formula is derived for the Peierls stress of dislocations in alternating lattices. The atomic relaxation is shown to play an important role on the Peierls stress. C1 Calif State Univ Northridge, Dept Phys, Northridge, CA 91330 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. RP Kioussis, N (reprint author), Calif State Univ Northridge, Dept Phys, Northridge, CA 91330 USA. NR 15 TC 41 Z9 42 U1 0 U2 9 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD OCT PY 2000 VL 80 IS 10 BP 675 EP 682 DI 10.1080/09500830050143778 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 360AT UT WOS:000089644800003 ER PT J AU Fu, CL Wang, XD AF Fu, CL Wang, XD TI Thermal expansion coefficients of Mo-Si compounds by first-principles calculations SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID ELASTIC-CONSTANTS; SINGLE-CRYSTALS; MO5SI3; METALS AB Taking Mo-Si compounds as model systems, we show that the coefficients of thermal expansion (CTEs) of complex structures can be calculated precisely from first principles by incorporating the Debye model for acoustic response. Specifically, we obtain a nearly isotropic CTE in MoSi2 but a highly anisotropic CTE in Mo5Si3. The CTE anisotropy in Mo5Si3 is due to an elastically more rigid basal plane and a higher anharmonicity along the c axis. As the structure of 5-3 compounds is modified from D8(m) to D8(l) by boron substitutions (Mo5SiB2), we predict a significant decrease in the CTE anisotropy, which is confirmed by experiments. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Fu, CL (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. NR 13 TC 29 Z9 31 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD OCT PY 2000 VL 80 IS 10 BP 683 EP 690 DI 10.1080/09500830050143787 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 360AT UT WOS:000089644800004 ER PT J AU Roberts, JE Wishart, JF Martinez, L Chignell, CF AF Roberts, JE Wishart, JF Martinez, L Chignell, CF TI Photochemical studies on xanthurenic acid SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID HUMAN LENS; OXYGEN; EYE; CONSTITUENTS; GLUCOSIDE; PROTEINS; AZIDE AB The tryptophan metabolite xanthurenic acid (Xan) has been isolated from aged human cataractous lenses. The photophysical properties of Xan were examined to determine if it is a potential chromophore for age-related cataractogenesis. We found that Xan produces singlet oxygen (phi (A) = 0.17 in CD3OD) with the same efficiency as the lenticular chromophore N-formyl kynurenine and quenches singlet oxygen at a rate similar (2.1 x 10(7); CD,OD) to other tryptophan metabolites found in the eye. As the mechanisms of induction of cataracts may also involve redox reactions, the interactions of hydrated electrons (e(aq)-), the azide radical (N-3(.)) and hydroxyl radical (OH.) with Xan were studied using the technique of pulse radiolysis. The reaction rate constants of e(aq)(-), N-3(.) and OH. with Xan were found to be of the same order of magnitude as other tryptophan metabolites. The rate constant for reaction of Xan with e(aq)(-) solvated electrons was found to be diffusion controlled (k = 1.43 x 10(10) M-1 s(-1)); the reaction with N-3(.) was very fast (k = 4.0 x 10(9) M-1 s(-1)); and with OH. was also near diffusion controlled (k = 1.0 x 10(10) M-1 s(-1)). Superoxide O-2(.-) production by irradiated Xan in methanol was detected by electron paramagnetic resonance and substantiated by determining that the enhanced rate of oxygen consumption of Xan irradiated in the presence of furfuryl alcohol was lowered by superoxide dismutase. C1 Fordham Univ, New York, NY 10023 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NIEHS, Lab Pharmacol & Chem, Res Triangle Pk, NC 27709 USA. RP Roberts, JE (reprint author), Fordham Univ, 113 W 60th St, New York, NY 10023 USA. RI Wishart, James/L-6303-2013 OI Wishart, James/0000-0002-0488-7636 NR 22 TC 26 Z9 27 U1 0 U2 4 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 USA SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD OCT PY 2000 VL 72 IS 4 BP 467 EP 471 DI 10.1562/0031-8655(2000)072<0467:PSOXA>2.0.CO;2 PG 5 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 366VU UT WOS:000090027600007 PM 11045716 ER PT J AU Moreno, NO Pagliuso, PG Rettori, C Gardner, JS Sarrao, JL Thompson, JD Huber, DL Garcia-Flores, A Oseroff, SB AF Moreno, NO Pagliuso, PG Rettori, C Gardner, JS Sarrao, JL Thompson, JD Huber, DL Garcia-Flores, A Oseroff, SB TI Extrinsic and intrinsic features above T-c in layered manganite: La1.2Sr1.8Mn2O7 SO PHYSICA B LA English DT Article DE electron paramagnectic resonance; layered-perovskite manganites; intrinsic properties ID SHORT-RANGE ORDER; GIANT-MAGNETORESISTANCE; SPIN DYNAMICS; MAGNETIC-RESONANCE; LA0.7SR0.3MNO3; EPR; MAGNETOIMPEDANCE; CRYSTAL; ESR AB We have performed EPR and DC magnetization measurements on single crystals of La1.2Sr1.8Mn2O7. Similar to previous authors, we found an increase in the magnetization, M, near 300 K, a temperature well above T-C similar to 125 K. Previously, this high temperature( similar to 300 K) feature has been suggested to be intrinsic to the system. We have observed at these high temperatures the appearance of new ferromagnetic resonances, FMR. Within the experimental error the volume of sample required to explain the extra M and the intensity of the FMR is the same. We conclude that the increase in M and the FMR are due to the presence of extrinsic Ruddlesden-Popper (RP) phases and not to intrinsic effects as has been claimed. Furthermore, the resonance field of the EPR line due to the La1.2Sr1.8Mn2O7 phase presents a measurable temperature-dependent anisotropy up to similar to 450 K. The anisotropy is proportional to M, independent of the extrinsic RP phase content, and intrinsic to the system. We show that demagnetization effects can explain only part of the anisotropy. The role of short-range magnetic ordering in the observed intrinsic features cannot be disregarded, however. (C) 2000 Elsevier Science B.V. All rights reserved. C1 UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Madison, WI 53706 USA. San Diego State Univ, San Diego, CA 92182 USA. RP Moreno, NO (reprint author), UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. RI Rettori, Carlos/C-3966-2012; Pagliuso, Pascoal/C-9169-2012; Moreno, Nelson/H-1708-2012; Gardner, Jason/A-1532-2013; Inst. of Physics, Gleb Wataghin/A-9780-2017 OI Rettori, Carlos/0000-0001-6692-7915; Moreno, Nelson/0000-0002-1672-4340; NR 28 TC 12 Z9 12 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD OCT PY 2000 VL 292 IS 1-2 BP 1 EP 8 DI 10.1016/S0921-4526(00)00496-8 PG 8 WC Physics, Condensed Matter SC Physics GA 353YX UT WOS:000089304000001 ER PT J AU Fournier, KB Stutman, D Vero, R Soukhanovskii, V Finkenthal, M May, MJ Shlyaptsev, VN Goldstein, WH AF Fournier, KB Stutman, D Vero, R Soukhanovskii, V Finkenthal, M May, MJ Shlyaptsev, VN Goldstein, WH TI Measurement of population inversion for FUV transitions in Kr-like YIV in a high-current reflex discharge SO PHYSICA SCRIPTA LA English DT Article ID X-RAY LASER; AMPLIFICATION; SPECTRUM; NB AB Kr-like ions are good candidates for FUV lasing since they can be produced in plasmas quite easily. We present results from a spectroscopic investigation of Y IV emission from a high current density, cold cathode reflex discharge. The Y II to Y V emission is recorded in the 200-3000 Angstrom range using photometrically calibrated spectrometers, while the emission of trace aluminum ions serves for plasma diagnostics. The intensities of the Y TV 4d-5p and 5s7-5p transitions strongly increase relative to lines from Y II and Y III with increasing plasma current. The spectra studied here are obtained at a current density of 1.75 A/cm(2). Experimental Y IV intensity ratios spanning several excited configurations are compared with collisional radiative predictions of the HULLAC atomic physics package. Good agreement is found for the measured and predicted ratios of 4p(5)5p to 4p(5)5s level populations per statistical weight. Finally, the response of the Kr-like system to a fast, transient excitation pulse is examined using the RADEX code. Large transient gains are predicted for several 5s-5p transitions in Kr-like Y IV. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Johns Hopkins Univ, Plasma Spect Grp, Baltimore, MD 21218 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. RP Fournier, KB (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808 L-41, Livermore, CA 94550 USA. RI Stutman, Dan/P-4048-2015 NR 28 TC 1 Z9 1 U1 0 U2 0 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PD OCT PY 2000 VL 62 IS 4 BP 301 EP 306 DI 10.1238/Physica.Regular.062a00301 PG 6 WC Physics, Multidisciplinary SC Physics GA 363UT UT WOS:000089855500013 ER PT J AU Budker, D Kimball, DF Rochester, SM Yashchuk, VV Zolotorev, M AF Budker, D Kimball, DF Rochester, SM Yashchuk, VV Zolotorev, M TI Sensitive magnetometry based on nonlinear magneto-optical rotation SO PHYSICAL REVIEW A LA English DT Article ID ATOMIC PHASE COHERENCE; FARADAY-ROTATION; SAMARIUM VAPOR; LASER; FIELDS; ORIENTATION; RESONANCE; QUANTUM AB Application of nonlinear magneto-optical (Faraday) rotation to magnetometry is investigated. Our experimental setup consists of a modulation polarimeter that measures rotation of the polarization plane of a laser beam resonant with transitions in Rb. Rb vapor is contained in an evacuated cell with antirelaxation coating that enables atomic ground-state polarization to survive many thousand wall collisions. This leads to ultranarrow features (similar to 10(-6) G) in the magnetic-field dependence of optical rotation. The potential sensitivity of this scheme to sub-mu G magnetic fields as a function of atomic density, light intensity, and light frequency is investigated near the D1 and D2 lines of (85)Rb. It is shown that through an appropriate choice of parameters the shot-noise-limited sensitivity to small magnetic fields can reach 3x10(-12) G/root Hz. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Beam Phys, Berkeley, CA 94720 USA. RP Budker, D (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM budker@socrates.berkeley.edu RI Budker, Dmitry/F-7580-2016 OI Budker, Dmitry/0000-0002-7356-4814 NR 45 TC 184 Z9 187 U1 5 U2 46 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 2000 VL 62 IS 4 AR 043403 DI 10.1103/PhysRevA.62.043403 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 360VU UT WOS:000089688700057 ER PT J AU Neto, PAM Dalvit, DAR AF Neto, PAM Dalvit, DAR TI Radiation pressure as a source of decoherence SO PHYSICAL REVIEW A LA English DT Article ID QUANTUM BROWNIAN-MOTION; DISPERSIVE MIRROR; MOVING MIRRORS; VACUUM; FLUCTUATIONS; ENVIRONMENT; FORCE; ELECTRODYNAMICS; DISSIPATION; FRICTION AB We consider the interaction of an harmonic oscillator with the quantum field via radiation pressure. We show that a "Schrodinger cat" state decoheres in a time scale that depends on the degree of ''classicality" of the state components, and which may be much shorter than the relaxation time scale associated to the dynamical Casimir effect. We also show that decoherence is a consequence of the entanglement between the quantum states of the oscillator and held two-photon states. With the help of the fluctuation-dissipation theorem, we derive a relation between decoherence and damping rates valid for arbitrary; values of the temperature of the field. Coherent states are selected by the interaction as pointer states. C1 Univ Fed Rio de Janeiro, Inst Fis, BR-21945970 Rio De Janeiro, Brazil. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Neto, PAM (reprint author), Univ Fed Rio de Janeiro, Inst Fis, Caixa Postal 68528, BR-21945970 Rio De Janeiro, Brazil. EM pamn@if.ufrj.br; dalvit@lanl.gov NR 30 TC 17 Z9 17 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 2000 VL 62 IS 4 AR 042103 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 360VU UT WOS:000089688700012 ER PT J AU Tannian, BE Stokely, CL Dunning, FB Reinhold, CO Yoshida, S Burgdorfer, J AF Tannian, BE Stokely, CL Dunning, FB Reinhold, CO Yoshida, S Burgdorfer, J TI Kicked Rydberg atom: Response to trains of unidirectional and bidirectional impulses SO PHYSICAL REVIEW A LA English DT Article ID QUANTUM CHAOS; DYNAMICAL STABILIZATION; IONIZATION; REGIME; FIELDS AB The behavior of Rb(390p) atoms subject to a train of up to 50 half-cycle pulses (HCPs) with duration T-p << T-n, where T-n is the classical electron orbital period, is investigated. In this limit, each HCP simply delivers an impulsive momentum transfer or "kick'' to the electron. The response of atoms to a series of unidirectional kicks and to a series of kicks that alternate in direction is compared. For unidirectional kicks, the Rydberg atom survival probability has a pronounced maximum when the pulse repetition frequency v(p) is similar to 1.3 times the classical orbital frequency v(n). Classical simulations show this behavior provides a signature of dynamical stabilization. Evidence of dynamical stabilization and chaotic diffusion is also found in the distribution of final bound states. Very different behavior is observed for alternating kicks. The survival probability generally increases with v(p), although a small local maximum is evident when v(p)similar to v(n) Little evidence of dynamical stabilization is observed in either the calculated dependence of the survival probability on the number of applied kicks, in the measured final bound-state distribution, or in the classical phase space of the kicked atom. Model calculations for a one-dimensional "atom" reveal islands of stability, but their three-dimensional counterparts are found to be unstable. C1 Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. Rice Univ, Rice Quantum Inst, Houston, TX 77005 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Tannian, BE (reprint author), Rice Univ, Dept Phys & Astron, 6100 Main St, Houston, TX 77005 USA. NR 15 TC 38 Z9 38 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 2000 VL 62 IS 4 AR 043402 DI 10.1103/PhysRevA.62.043402 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 360VU UT WOS:000089688700056 ER PT J AU Tantawi, RS Sabbah, AS Macek, JH Ovchinnikov, SY AF Tantawi, RS Sabbah, AS Macek, JH Ovchinnikov, SY TI Two-state model for top-of-barrier processes SO PHYSICAL REVIEW A LA English DT Article ID IONIZATION; COLLISIONS; ELECTRONS; THRESHOLD; HYDROGEN; PROTONS; HE AB A two-state model applicable to top-of-barrier processes in ion-atom collisions at low velocity v is investigated. An expression for the Massey parameter of the transition n-->n + 1 is derived and is used to compute ionization, capture, and excitation from states (of high principal quantum number in H+ + H collisions. The Wannier law is obtained at the ionization threshold. The dependence of ionization on the initial n is computed. Total capture cross sections are in good agreement with other calculations, but an unreasonably large fraction goes to resonant capture. It is concluded that multicrossing models, which do nor incorporate interference between different paths to the resonant state, overestimate resonant capture. C1 Zagazig Univ, Dept Math, Zagazig, Egypt. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. RP Tantawi, RS (reprint author), Zagazig Univ, Dept Math, Zagazig, Egypt. RI Ovchinnikov, Serguei/C-4994-2014 NR 30 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 2000 VL 62 IS 4 AR 042710 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 360VU UT WOS:000089688700049 ER PT J AU Lee, BJ Baskes, MI AF Lee, BJ Baskes, MI TI Second nearest-neighbor modified embedded-atom-method potential SO PHYSICAL REVIEW B LA English DT Article ID METALS; SILICON AB The modified embedded-atom method, a first nearest-neighbor semiempirical model fur atomic potentials, can describe the physical properties of a wide range of elements and alloys with various lattice structures. However, the model is not quite successful for bcc metals in that it predicts the order among the size of low index surface energies incorrectly and that it generates a structure more stable than bcc for some bcc metals. In order to remove the problems, the formalism has been extended so that the second nearest neighbor interactions are taken into consideration. New parameters for Fe and comparisons between calculated and experimental physical properties of Fe are presented. C1 Korea Res Inst Stand & Sci, Mat Evaluat Ctr, Taejon 305600, South Korea. Univ Calif Los Alamos Natl Lab, Struct Properties Relat Grp, Los Alamos, NM 87545 USA. RP Lee, BJ (reprint author), Korea Res Inst Stand & Sci, Mat Evaluat Ctr, Yusong POB 102, Taejon 305600, South Korea. NR 16 TC 218 Z9 222 U1 1 U2 37 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 OCT 1 PY 2000 VL 62 IS 13 BP 8564 EP 8567 DI 10.1103/PhysRevB.62.8564 PG 4 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800002 ER PT J AU Welp, U Berger, A Vlasko-Vlasov, VK Li, QA Gray, KE Mitchell, JF AF Welp, U Berger, A Vlasko-Vlasov, VK Li, QA Gray, KE Mitchell, JF TI Magnetic anisotropy and domain structure of the layered manganite La1.36Sr1.64Mn2O7 SO PHYSICAL REVIEW B LA English DT Article ID CRYSTAL AB The magnetic anisotropy and domain structure of La1.36Sr1.64Mn2O7 were investigated using magnetooptical imaging and magnetization measurements. First and second order anisotropy constants of K-1=2.5 X 10(5) erg/cm(3) and K-2=2.8X10(5) erg/cm(3) at 20 K are obtained. With increasing temperature K-1 and K-2 drop rapidly until K1 changes sign near 80 K. A model of near cancellation of a strong single-ion anisotropy (k(u) similar or equal to 0.7X10(6)erg/cm(3) at 20 K) and large dipolar effects originating from the layered structure can account for the observed anisotropy. Below 75 K a well developed maze shaped domain pattern with 10 mu m domain width is observed which shows signatures of domain branching and flux closure typical for a moderately anisotropic uniaxial magnet. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Li, Qingan/L-3778-2013; Berger, Andreas/D-3706-2015 OI Berger, Andreas/0000-0001-5865-6609 NR 24 TC 24 Z9 25 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 2000 VL 62 IS 13 BP 8615 EP 8618 DI 10.1103/PhysRevB.62.8615 PG 4 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800015 ER PT J AU Crespi, VH Cohen, ML AF Crespi, VH Cohen, ML TI Validity of the BCS model Hamiltonian in the limit of small sizes SO PHYSICAL REVIEW B LA English DT Article ID ULTRASMALL METALLIC GRAINS; SUPERCONDUCTIVITY AB Finite-size effects when the electronic level spacings become comparable to the bulk superconducting gap can suppress pairing correlations in small metallic particles. We examine an alternative mechanism for finite-size suppression of superconductivity: the role of the nonpair portion of the interaction, which could become important in small systems. We show that the crossover size at which the nonpair contribution becomes significant is typically already within the regime wherein finite lever spacing suppresses the pairing correlations; however, the nonpair terms could become relevant in certain weak-coupled superconductors. C1 Penn State Univ, Dept Phys, Davey Lab 104, University Pk, PA 16802 USA. Penn State Univ, Ctr Phys Mat, Davey Lab 104, University Pk, PA 16802 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Crespi, VH (reprint author), Penn State Univ, Dept Phys, Davey Lab 104, University Pk, PA 16802 USA. OI Crespi, Vincent/0000-0003-3846-3193 NR 13 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 OCT 1 PY 2000 VL 62 IS 13 BP 8669 EP 8670 DI 10.1103/PhysRevB.62.8669 PG 2 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800029 ER PT J AU Shaked, H Jorgensen, JD Short, S Chmaissem, O Ikeda, SI Maeno, Y AF Shaked, H Jorgensen, JD Short, S Chmaissem, O Ikeda, SI Maeno, Y TI Temperature and pressure effects on the crystal structure of Sr3Ru2O7: Evidence for electronically driven structural responses SO PHYSICAL REVIEW B LA English DT Article ID THERMAL-EXPANSION; PEROVSKITE AB The crystal structure of the ruthenate Sr3Ru2O7 as a function of temperature (5-305 K) and pressure (ambient -0.62 GPa) was studied by neutron diffraction. Upon cooling, the lattice parameter c and the rotation angle of the oxygen octahedra phi increase for 305K>T>50K, and decrease for 20K>T>5K As pressure is applied at room temperature, the outer apical Ru-O bond expands. This remarkable behavior is discussed in terms of modification of the occupation of energy levels of the Ru4+ ion in the crystalline electric field of the oxygen octahedron and a crossover to Fermi-liquid behavior at low temperature. The very anisotropic thermal expansion leads, in sintered powder samples, to a high degree of strain, which is relieved somewhat with each cooling cycle. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Kyoto Univ, Dept Phys, Kyoto 6068502, Japan. Japan Sci & Technol Corp, Core Res Evolutionary Sci, Kawaguchi, Saitama 3320012, Japan. Ben Gurion Univ Negev, Dept Phys, IL-84190 Beer Sheva, Israel. Electrotech Lab, Div Phys Sci, Tsukuba, Ibaraki 3058568, Japan. RP Shaked, H (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Ikeda, Shinichi/I-5829-2012 OI Ikeda, Shinichi/0000-0003-2134-7786 NR 23 TC 39 Z9 39 U1 4 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 OCT 1 PY 2000 VL 62 IS 13 BP 8725 EP 8730 DI 10.1103/PhysRevB.62.8725 PG 6 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800043 ER PT J AU Zhao, YS Lawson, AC Zhang, JZ Bennett, BI Von Dreele, RB AF Zhao, YS Lawson, AC Zhang, JZ Bennett, BI Von Dreele, RB TI Thermoelastic equation of state of molybdenum SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-DIFFRACTION; NEUTRON-DIFFRACTION; POWDER DIFFRACTION; SOLIDS; CELL; NACL AB We report some high P-T diffraction experimental results on molybdenum using synchrotron x-ray and time-of-flight neutron-diffraction techniques. Unit-cell dimensions, measured up to P = 10 GPa and T = 1475 K, were derived from the refinement results and fitted to a high-temperature third-order Birch-Murnaghan equation of state. The derived thermoelastic parameters for molybdenum are: isothermal bulk modulus K-T0 = 266(9) GPa with a pressure derivative of bulk modulus partial derivative K/partial derivative P = 4.1(9), temperature derivative of bulk modulus partial derivative K/partial derivative T = -3.4(9) X 10(-2)GPa/K, volumetric thermal expansivity alpha = a + bT having a = 1.32(14) x 10(-5) K-1 and b = 1.26(15) X 10(-8) K-2. Further, all of the previous experimental data involving shock wave, ultrasonic, thermal-expansion measurements were also analyzed and fitted to a high-temperature Birch/Vinet equation of state (EOS) and the thermal pressure approach of Mie-Gruneisen EOS, respectively. With the greatly extended P-V-T data coverage, we refined the thermoelastic parameter set for molybdenum as isothermal bulk modulus K-T0 = 268(1) GPa with pressure derivatives of bulk modulus partial derivative K/partial derivative P = 3.81(6), partial derivative K-2/partial derivative P-2 = -1.41(13) X 10(-2), temperature derivative of bulk modulus partial derivative K/partial derivative T = -2.13(31) X 10(-2) GPa/K, volumetric thermal expansivity alpha = a + bT having a = 1.31(10) x 10(-5) K-1 and b = 1.12(11) X 10(-8) K-2, and an invariant of alpha K-T,= 5.43(5) X 10(-3) GPa/K over a wide P-T range. We have conducted a neutron-diffraction study at simultaneous high pressures and high temperatures. Thermal vibrations of atoms (Debye-Waller factors) of molybdenum were derived as a function of pressure and temperature. The experimental results of thermoelastic equation of state parameters are compared with previous experimental data derived from shock wave and ultrasonic elasticity measurements. C1 Univ Calif Los Alamos Natl Lab, LANSCE, Los Alamos, NM 87545 USA. SUNY Stony Brook, CHiPR, Stony Brook, NY 11794 USA. RP Zhao, YS (reprint author), Univ Calif Los Alamos Natl Lab, LANSCE, POB 1663, Los Alamos, NM 87545 USA. RI Lujan Center, LANL/G-4896-2012 NR 39 TC 50 Z9 50 U1 1 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 2000 VL 62 IS 13 BP 8766 EP 8776 DI 10.1103/PhysRevB.62.8766 PG 11 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800048 ER PT J AU Zheludev, A Masuda, T Tsukada, I Uchiyama, Y Uchinokura, K Boni, P Lee, SH AF Zheludev, A Masuda, T Tsukada, I Uchiyama, Y Uchinokura, K Boni, P Lee, SH TI Magnetic excitations in coupled Haldane spin chains near the quantum critical point SO PHYSICAL REVIEW B LA English DT Article ID DIMENSIONAL HEISENBERG-ANTIFERROMAGNET; NEUTRON-SCATTERING; GAP ANTIFERROMAGNETS; SIGMA-MODEL; DYNAMICS; CSNICL3; INTEGER; Y2BANIO5; SYSTEMS; CSMNI3 AB Two quasi-one-dimensional S = 1 quantum antiferromagnetic materials, PbNi2V2O8 and SrNi2V2O8, are studied by inelastic neutron scattering on powder samples. A simple model Hamiltonian is proposed for the two systems and used to analyze the data. Quantitative information on in-chain and interchain interactions obtained from this analysis is discussed in the context of qualitatively different ground-state properties: magnetic long-range order in SrNi2V2O8 and disordered "spin liquid" Haldane-gap state in PbNi2V2O8. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138656, Japan. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Tokyo, Dept Adv Mat Sci, Tokyo, Japan. RP Zheludev, A (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. NR 32 TC 52 Z9 52 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 OCT 1 PY 2000 VL 62 IS 13 BP 8921 EP 8930 DI 10.1103/PhysRevB.62.8921 PG 10 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800069 ER PT J AU Cao, D Bridges, F Booth, CH Neumeier, JJ AF Cao, D Bridges, F Booth, CH Neumeier, JJ TI Changes in the local structure of a La0.70Ca0.30MnO3CMR sample induced by a magnetic field SO PHYSICAL REVIEW B LA English DT Article ID COLOSSAL-MAGNETORESISTANCE; DOUBLE EXCHANGE; LA1-XCAXMNO3; TEMPERATURE; RESISTIVITY; LA1-XSRXMNO3; DISTORTIONS; MANGANITES; FILMS AB We investigated the effect of an applied magnetic field on the local distortions of MnO6 octahedra in a La0.70Ca0.30MnO3 colossal magnetoresistive (CMR) sample. Previously we have shown that the variance sigma(2)(T) for the Mn-O pair distribution function is a function of the magnetization M(T); however, in the earlier study, each point is at a different temperature. Since an external magnetic field directly controls the sample magnetization, we expect to observe a corresponding change in sigma(2) of a CMR sample when a magnetic field B is applied at a fixed temperature. Two field-orientations were used with B parallel and perpendicular (horizontally) to the x-ray polarization vector P. Our measurements verify that the local distortion does indeed change with B near T-c, as expected. C1 Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Florida Atlantic Univ, Dept Phys, Boca Raton, FL 33431 USA. RP Cao, D (reprint author), Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. RI Booth, Corwin/A-7877-2008 NR 29 TC 9 Z9 9 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 2000 VL 62 IS 13 BP 8954 EP 8958 DI 10.1103/PhysRevB.62.8954 PG 5 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800074 ER PT J AU Kogan, VG Bud'ko, SL Fisher, IR Canfield, PC AF Kogan, VG Bud'ko, SL Fisher, IR Canfield, PC TI Nonlocal effects in magnetization of high-kappa superconductors SO PHYSICAL REVIEW B LA English DT Article ID VORTEX LATTICE TRANSITIONS; FLUX-LINE-LATTICE; HIGH-T(C) SUPERCONDUCTORS; REVERSIBLE MAGNETIZATION; NEUTRON-SCATTERING; PENETRATION DEPTH; LUNI2B2C; YNI2B2C; FLUCTUATIONS; FIELD AB The reversible magnetization M(T,H) in high quality single crystals of Lu(Ni1-xCox)(2)B2C with x=0-0.09 is measured in a broad T,H domain and interpreted within London theory corrected for nonlocality of the current - vector-potential relation. Profound deviations in the data from the standard London result, M proportional to ln(H-c2/H) in intermediate fields H(c1)much less than H much less than H-c2, are seen in clean samples at low T's. Unlike strongly anisotropic high-T-c compounds, for nearly isotropic borocarbides this behavior cannot be attributed to fluctuations of weakly interacting pancake vortices. We show that the nonlocal London model describes qualitatively and consistently the whole set of M(T,H) data and, in particular, its temperature and the mean-free path dependence. The scaling field H-0, which arises in M=M(H/H-0) due to nonlocality, is found to be nearly proportional to the the field H-2 at which the vortex lattice undergoes the symmetry change (the "square-tohex" transition). C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Kogan, VG (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 33 TC 10 Z9 10 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 OCT 1 PY 2000 VL 62 IS 13 BP 9077 EP 9082 DI 10.1103/PhysRevB.62.9077 PG 6 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800090 ER PT J AU Martin, JI Velez, M Hoffmann, A Schuller, IK Vicent, JL AF Martin, JI Velez, M Hoffmann, A Schuller, IK Vicent, JL TI Temperature dependence and mechanisms of vortex pinning by periodic arrays of Ni dots in Nb films SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTING FILMS; MAGNETOSTATIC INTERACTIONS; II SUPERCONDUCTORS; REGULAR ARRAY; MAGNETIC DOTS; FLUX; LITHOGRAPHY; VORTICES; LATTICE; CURRENTS AB Pinning interactions between superconducting vortices in Nb and magnetic Ni dots were studied as a function of current and temperature to clarify the nature of pinning mechanisms. A strong current dependence is found for a square array of dots, with a temperature-dependent optimum current for the observation of periodic pinning, which decreases with temperature as (1-TITC)(3/2). This same temperature dependence is found for the critical current at the first matching field with a rectangular array of dots. The analysis of these results allows one to narrow the possible pinning mechanisms to a combination of two: the interaction between the vortex and the magnetic moment of the dot and the proximity effect. Moreover, fur the rectangular dot array, the temperature dependence of the crossover between the Low-field regime with a rectangular vortex lattice to the high-field regime with a square configuration has been studied. It is found that the crossover field increases with decreasing temperature. This dependence indicates a change in the balance between elastic and pinning energies, associated with the dynamical effects of the vortex lattice in the high-held range. C1 Univ Complutense, Fac Fis, Dept Fis Mat, E-28040 Madrid, Spain. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Los Alamos Natl Lab, Manuel Lujan Jr Neutron Scattering Ctr, Los Alamos, NM 87545 USA. RP Univ Oviedo, Dept Fis, F Ciencias, E-33007 Oviedo, Spain. RI Velez, Maria/A-2734-2012; Martin, Jose/C-5250-2013; Hoffmann, Axel/A-8152-2009 OI Velez, Maria/0000-0003-0311-7434; Martin, Jose/0000-0003-2256-0909; Hoffmann, Axel/0000-0002-1808-2767 NR 29 TC 64 Z9 64 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 2000 VL 62 IS 13 BP 9110 EP 9116 DI 10.1103/PhysRevB.62.9110 PG 7 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800094 ER PT J AU Matsuda, M Fujita, M Yamada, K Birgeneau, RJ Kastner, MA Hiraka, H Endoh, Y Wakimoto, S Shirane, G AF Matsuda, M Fujita, M Yamada, K Birgeneau, RJ Kastner, MA Hiraka, H Endoh, Y Wakimoto, S Shirane, G TI Static and dynamic spin correlations in the spin-glass phase of slightly doped La2-xSrxCuO4 SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-SCATTERING; HUBBARD-MODEL; DENSITY-WAVE; ORDER; MAGNETISM; FLUCTUATIONS; TEMPERATURE; TRANSITION; LA2CUO4; HOLES AB Neutron-scattering experiments reveal that a diagonal spin modulation, which is a one-dimensional modulation rotated away by 45 degrees from that in the superconducting phase, occurs universally across the insulating spin-glass phase in La2-xSrxCuO4 (0.02 less than or equal to x less than or equal to 0.055). This establishes an intimate relation between the magnetism and the transport properties in the high-temperature copper oxide superconductors. Furthermore, it is found that the charge density per unit length estimated using a charge stripe model is almost constant throughout the phase diagram, even when the modulation rotates away by 45 degrees at the superconducting boundary. However. at the lowest values for I the density changes approaching 1 hole/Cu as in La2-xSrxNiO4. Magnetic excitation spectra suggest that magnetic correlations change from incommensurate to commensurate at omega similar to 7 meV and T similar to 70 K, indicating a characteristic energy for the incommensurate structure of 6-7 meV. C1 RIKEN, Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Kyoto Univ, Chem Res Inst, Uji 6100011, Japan. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. Tohoku Univ, Inst Mat Res, Sendai, Miyagi 9808577, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Japan Atom Energy Res Inst, Adv Sci Res Ctr, Tokai, Ibaraki 3111195, Japan. RI Yamada, Kazuyoshi/C-2728-2009; Fujita, Masaki/D-8430-2013; Matsuda, Masaaki/A-6902-2016 OI Matsuda, Masaaki/0000-0003-2209-9526 NR 29 TC 144 Z9 144 U1 3 U2 16 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 2000 VL 62 IS 13 BP 9148 EP 9154 DI 10.1103/PhysRevB.62.9148 PG 7 WC Physics, Condensed Matter SC Physics GA 361QH UT WOS:000089733800099 ER PT J AU Stetzer, MR Heiney, PA Stephens, PW Dinnebier, RE Zhu, Q McGhie, AR Strongin, RM Brandt, BM Smith, AB AF Stetzer, MR Heiney, PA Stephens, PW Dinnebier, RE Zhu, Q McGhie, AR Strongin, RM Brandt, BM Smith, AB TI Structure and phase transitions of the 6,6-cyclopropane isomer of C61H2 SO PHYSICAL REVIEW B LA English DT Article ID ORIENTATIONAL ORDERING TRANSITION; INTERCALATED C-60 CRYSTALS; SOLID C-60; FULLERENE; C60; DYNAMICS; DISORDER; C70; DIFFRACTION; EPOXIDE AB We have used x-ray powder diffraction and differential scanning calorimetry to study the crystalline structures and thermal behavior of the 6,6-cyclopropane isomer of C61H2. At room temperature, the C61H2 cyclopropane molecules, like those of the 6,5-annulene isomer and C60O epoxide, are orientationally disordered and crystallize on a face-centered-cubic lattice such that their methylene groups are statistically disordered among the octahedral voids. Unlike 6,5-C61H2 and C60O, the low-temperature structure is not Pa (3) over bar, but rather a low-symmetry orthorhombic lattice in which a approximate to b (293)118 + In may be due to the sinking of the Coulomb barrier below the level of the bombarding energy. Tests of this hypothesis are suggested. Some consequences of the appearance of such "unshielded" reactions for very heavy systems are discussed. An Appendix supplies very accurate analytic formulas for the universal nuclear proximity force and potential functions phi and Phi. This does away with the need to consult the tables published in 1977. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Myers, WD (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 31 TC 159 Z9 165 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 044610 DI 10.1103/PhysRevC.62.044610 PG 7 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000046 ER PT J AU Oganessian, YT Utyonkov, VK Lobanov, YV Abdullin, FS Polyakov, AN Shirokovsky, IV Tsyganov, YS Gulbekian, GG Bogomolov, SL Gikal, BN Mezentsev, AN Iliev, S Subbotin, VG Sukhov, AM Ivanov, OV Buklanov, GV Subotic, K Itkis, MG Moody, KJ Wild, JF Stoyer, NJ Stoyer, MA Lougheed, RW AF Oganessian, YT Utyonkov, VK Lobanov, YV Abdullin, FS Polyakov, AN Shirokovsky, IV Tsyganov, YS Gulbekian, GG Bogomolov, SL Gikal, BN Mezentsev, AN Iliev, S Subbotin, VG Sukhov, AM Ivanov, OV Buklanov, GV Subotic, K Itkis, MG Moody, KJ Wild, JF Stoyer, NJ Stoyer, MA Lougheed, RW TI Synthesis of superheavy nuclei in the Ca-48+Pu-244 reaction: (288)114 SO PHYSICAL REVIEW C LA English DT Article ID ISOTOPES; STABILITY; N=162; CA-48 AB In the bombardment of a Pu-244 target with Ca-48 ions, we observed two identical decay sequences of genetically linked events, each consisting of an implanted heavy atom, two subsequent alpha decays, and terminated by a spontaneous fission. The measured alpha energies and corresponding half-lives of the sequential chain members were E-alpha = 9.84 +/- 0.05 MeV (T-1/2 = 1.9(-0.8)(+3.3) s) and 9.17 +/- 0.05 MeV (T-1/2 = 9.8(-3.8)(+18) s); for the spontaneous fission (T-1/2 = 75(-2.9)(+14) s), the total energies deposited in the detector array were 213 +/- 2 and 221 +/- 2 MeV. The decay properties of the synthesized nuclei are consistent with the consecutive a decays originating from the parent even-even nucleus (288)114, produced in the 4n-evaporation channel with a cross section of about 1 pb. (288)114 and (284)112 are the heaviest known alpha-decaying even-even nuclides, following the production of (260)Sg and (266)Sg (Z = 106) and the observation of alpha decay of (264)Hs (Z = 108). The observed radioactive properties of (288)114 and the daughter nuclides match the decay scenario predicted by the macroscopic-microscopic theory. C1 Joint Inst Nucl Res, Dubna 141980, Russia. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Oganessian, YT (reprint author), Joint Inst Nucl Res, Dubna 141980, Russia. NR 29 TC 213 Z9 220 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 041604 DI 10.1103/PhysRevC.62.041604 PG 4 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000006 ER PT J AU Ogloblin, AA Glukhov, YA Trzaska, WH Dem'yanova, AS Goncharov, SA Julin, R Klebnikov, SV Mutterer, M Rozhkov, MV Rudakov, VP Tiorin, GP Khoa, DT Satchler, GR AF Ogloblin, AA Glukhov, YA Trzaska, WH Dem'yanova, AS Goncharov, SA Julin, R Klebnikov, SV Mutterer, M Rozhkov, MV Rudakov, VP Tiorin, GP Khoa, DT Satchler, GR TI New measurement of the refractive, elastic O-16+C-12 scattering at 132, 170, 200, 230, and 260 MeV incident energies SO PHYSICAL REVIEW C LA English DT Article ID COUPLED-CHANNELS CALCULATIONS; O-16+O-16 SYSTEM; POTENTIALS; EXCHANGE AB For the first time, differential cross section of the O-16+ C-12 elastic scattering at E-lab = 170, 200, 230, and 260 MeV has been measured over a wide angular range which covers both diffractive and refractive regions. In addition, the recent data at 132 MeV for this system have been remeasured with much better statistics. A well developed rainbow structure has been observed, where up to three Airy minima could be identified in each measured angular distribution. The optical model analysis of these data was done using the conventional Woods-Saxon shape for the optical potential as well as that given by the folding model. The Airy systematics enabled us to suggest a realistic family of the optical potential for the O-16+ C-12 system, which consistently describes the new data as well as the data measured earlier at incident energies of 608 and 1503 MeV. Our results show that the O-16+ C-12 system is a very suitable heavy-ion combination for the study of refractive phenomena, which can give important information on the nucleus-nucleus potential at small distances. C1 RSC Kurchatov Inst, RU-123182 Moscow, Russia. Univ Jyvaskyla, Dept Phys, FIN-40351 Jyvaskyla, Finland. Moscow MV Lomonosov State Univ, Inst Nucl Phys, RU-119899 Moscow, Russia. VG Khlopin Radium Inst, RU-197022 St Petersburg, Russia. Tech Univ Darmstadt, D-64289 Darmstadt, Germany. VAEC, Inst Nucl Sci & Tech, Hanoi, Vietnam. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. RP RSC Kurchatov Inst, RU-123182 Moscow, Russia. RI Khoa, Dao/B-9640-2009 NR 34 TC 60 Z9 62 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 044601 DI 10.1103/PhysRevC.62.044601 PG 9 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000037 ER PT J AU Starosta, K LaFosse, DR Chiara, CJ Fossan, DB Koike, T Lane, GJ Sears, JM Smith, JF Boston, AJ Nolan, PJ Paul, ES Semple, AT Devlin, M Sarantites, DG Lee, IY Macchiavelli, AO AF Starosta, K LaFosse, DR Chiara, CJ Fossan, DB Koike, T Lane, GJ Sears, JM Smith, JF Boston, AJ Nolan, PJ Paul, ES Semple, AT Devlin, M Sarantites, DG Lee, IY Macchiavelli, AO TI Excited states in I-110 and core polarization effects of the h(11/2) proton and neutron orbitals SO PHYSICAL REVIEW C LA English DT Article ID RADIOACTIVITY; SPECTROSCOPY; I-109 AB Excited states in I-110 have been identified for the first time using the alpha pn evaporation channel from the Ni-58+Ni-58 reaction at a beam energy of 250 MeV. The experiment was carried out using GAMMASPHERE coupled to the MICROBALL charged-particle detector array and an array of 15 neutron detectors. Two collective structures were observed with the yrast band built on the pi h(11/2) x nu h(11/2) configuration. Comparisons of the yrast-band energies with the excitation energies of the yrast states in even Te-52 and in odd Te-52 and I-53 isotopes for A similar to 110 were analyzed, revealing different responses of the underlying cores to the valence pi h(11/2) and nu h(11/2) orbitals. It is concluded that the neutron h(11/2) valence orbital has a larger influence than that of the proton h(11/2) valence orbital. C1 SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Starosta, K (reprint author), SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RI Lane, Gregory/A-7570-2011; Devlin, Matthew/B-5089-2013 OI Lane, Gregory/0000-0003-2244-182X; Devlin, Matthew/0000-0002-6948-2154 NR 13 TC 4 Z9 4 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 044309 DI 10.1103/PhysRevC.62.044309 PG 4 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000025 ER PT J AU Urban, W Phillips, WR Schulz, N Gall, BJP Ahmad, I Bentaleb, M Durell, JL Jones, MA Leddy, MJ Lubkiewicz, E Morss, LR Smith, AG Varley, BJ AF Urban, W Phillips, WR Schulz, N Gall, BJP Ahmad, I Bentaleb, M Durell, JL Jones, MA Leddy, MJ Lubkiewicz, E Morss, LR Smith, AG Varley, BJ TI Excited states in Te-139 and the properties of r-process nuclei with Z similar to 50 and N > 86 SO PHYSICAL REVIEW C LA English DT Article ID GAMMA-RAYS; SPONTANEOUS FISSION; FRAGMENTS; PARITIES AB Excited states in Te-139 were observed for the first time, using EUROGAM2 multidetector array to measure prompt-gamma radiation following the spontaneous fission of Cm-248. The systematic behavior of excitation energies in the N = 87 isotones and the multipolarity measurements suggest spin 7/2(-) for the ground state and 9/2(-) for the 271.0 keV level in Te-139. The 271.0 keV level most likely corresponds to the nu hg(9/2) single-particle excitation. A shape transition from spherical to prolate Te isotopes is observed at the neutron number N = 87, in accord with the Hartree-Fock plus BCS, PES calculations. Predictions for excitations in the Sn-137 nucleus are made based on the extended systematics obtained for the N = 87 isotones. C1 Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Manchester, Dept Phys & Astron, Schuster Lab, Manchester M13 9PL, Lancs, England. Inst Rech Subatom, UMR7500, CNRS, IN2P3, F-67037 Strasbourg, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Kenitra, Kenitra, Morocco. Jagiellonian Univ, Dept Phys, PL-300595 Krakow, Poland. RP Urban, W (reprint author), Univ Warsaw, Inst Expt Phys, Ul Hoza 69, PL-00681 Warsaw, Poland. NR 16 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 044315 DI 10.1103/PhysRevC.62.044315 PG 5 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000031 ER PT J AU Wong, CY Swanson, ES Barnes, T AF Wong, CY Swanson, ES Barnes, T TI Cross sections for pi- and rho-induced dissociation of J/psi and psi ' SO PHYSICAL REVIEW C LA English DT Article ID QUARK POTENTIAL MODEL; HEAVY-ION COLLISIONS; NUCLEAR COLLISIONS; HADRONIC MATTER; SPS ENERGIES; SUPPRESSION; SCATTERING; ABSORPTION; EXCHANGE AB We evaluate the cross sections for the dissociation of J/psi and psi' by pi and rho at low collision energies, using the quark-interchange model of Barnes and Swanson. The dissociation cross section for J/psi by pi is found to be relatively small with a maximum of about 1 mb and a kinetic energy threshold of 0.65 GeV. The pion-induced psi' dissociation cross section is found to be much larger, with a maximum of about 5 mb and a lower threshold. Dissociation cross sections for J/psi and psi' by rho mesons are also evaluated and are found to be large near threshold. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Jefferson Lab, Newport News, VA 23606 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. Univ Bonn, Inst Theoret Kernphys, D-53115 Bonn, Germany. Forschungszentrum Julich, Inst Kernphys, D-52425 Julich, Germany. RP Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. NR 32 TC 94 Z9 96 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 045201 DI 10.1103/PhysRevC.62.045201 PG 5 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000059 ER PT J AU Wu, SC Donangelo, R Rasmussen, JO Daniel, AV Hwang, JK Ramayya, AV Hamilton, JH AF Wu, SC Donangelo, R Rasmussen, JO Daniel, AV Hwang, JK Ramayya, AV Hamilton, JH TI New determination of the Ba-Mo yield matrix for Cf-252 SO PHYSICAL REVIEW C LA English DT Article ID SPONTANEOUS FISSION; NEUTRON-RICH; OCTUPOLE CORRELATIONS; BARIUM ISOTOPES; FRAGMENT PAIRS; IDENTIFICATION; DEFORMATION AB Using triple-coincidence events of prompt fission gamma rays from 1995 Gammasphere data on spontaneous fission of Cf-252, We made a careful analysis of the yield matrix of coincident pairs of barium (Z = 56) and molybdenum (Z=42) fission fragments. Branching from gamma bands (K=2) and octupole bands (K=0) are presented for even-even partners, where observable. From this reanalysis the previously proposed "extra-hot-fission mode" (up to ten neutrons evaporated) as determined by twofold coincidences of 1993 Gammasphere data is much weaker, but not excluded. This finding is in agreement with a recently published similar study from the Legnaro gamma-detector array. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Tsing Hua Univ, Dept Phys, Hsinchu, Taiwan. Univ Fed Rio de Janeiro, Inst Fis, BR-21945970 Rio De Janeiro, Brazil. Joint Nucl Res Inst, Flerov Lab Nucl React, Dubna, Russia. RP Wu, SC (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 20 TC 12 Z9 12 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 041601 PG 4 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000003 ER PT J AU Yu, CH Baktash, C Dobaczewski, J Cameron, JA Devlin, M Eberth, J Galindo-Uribarri, A Haslip, DS LaFosse, DR Lampman, TJ Lee, IY Lerma, F Macchiavelli, AO Paul, SD Radford, DC Rudolph, D Sarantites, DG Svensson, CE Waddington, JC Wilson, JN AF Yu, CH Baktash, C Dobaczewski, J Cameron, JA Devlin, M Eberth, J Galindo-Uribarri, A Haslip, DS LaFosse, DR Lampman, TJ Lee, IY Lerma, F Macchiavelli, AO Paul, SD Radford, DC Rudolph, D Sarantites, DG Svensson, CE Waddington, JC Wilson, JN TI Superdeformed and highly deformed bands in Zn-65 and neutron-proton interactions in Zn isotopes SO PHYSICAL REVIEW C LA English DT Article ID A-SIMILAR-TO-60 MASS REGION; HARMONIC-OSCILLATOR BASIS; HARTREE-FOCK EQUATIONS; ROTATIONAL BAND; NUCLEI; DECAY AB Superdeformed and highly deformed rotational bands were established in Zn-65 using the Ca-40(Si-29,4p)Zn-65 reaction, and averaged quadrupole moments were measured for two of these bands. The configurations of these bands were assigned based on Hartree-Fock calculations. One of the three bands exhibits at low (h) over bar omega a rise in the J((2)) dynamic moments of inertia that is similar to the alignment gain observed in Zn-60. A comparison of the rotational band configurations and their J((2)) moments of inertia for light Zn isotopes suggests that the rise in J((2)) is most likely caused by np interactions associated with the valence protons and neutrons occupying the g(9/2) intruder orbits. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Cologne, Inst Kernphys, D-50937 Cologne, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Oak Ridge Inst Sci & Educ, Oak Ridge, TN 37831 USA. Univ Lund, Dept Phys, S-22100 Lund, Sweden. RP Yu, CH (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. RI Rudolph, Dirk/D-4259-2009; radford, David/A-3928-2015; Devlin, Matthew/B-5089-2013 OI Rudolph, Dirk/0000-0003-1199-3055; Devlin, Matthew/0000-0002-6948-2154 NR 21 TC 17 Z9 17 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD OCT PY 2000 VL 62 IS 4 AR 041301 PG 5 WC Physics, Nuclear SC Physics GA 363YV UT WOS:000089866000002 ER PT J AU Abbott, B Abolins, M Abramov, V Acharya, BS Adams, DL Adams, M Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Bassler, U Bean, A Belyaev, A Beri, SB Bernardi, G Bertram, I 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 Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cochran, J Coney, L Connolly, B Cooper, WE Coppage, D Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Doulas, S Draper, P Ducros, Y Dudko, LV 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 Grannis, PD Green, JA Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G 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 Ito, AS Jerger, SA Jesik, R Joffe-Minor, T 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 Landsberg, G Leflat, A Lehner, F Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lu, JG Lucotte, A Lueking, L Lundstedt, C Maciel, AKA Madaras, RJ Manankov, V Mani, S 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 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 Piegaia, R Piekarz, H Pope, BG Popkov, E Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Reay, NW Reucroft, S 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 Song, XF 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 Thomas, TLT Thompson, J Toback, D Trippe, TG Turcot, AS Tuts, PM van Gemmeren, P Vaniev, V Van Kooten, R Varelas, N Volkov, AA Vorobiev, AP Wahl, HD Wang, H Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Whiteson, D Wightman, JA 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 Akimov, V Alves, GA Amos, N Anderson, EW Baarmand, MM Babintsev, VV Babukhadia, L Baden, A Baldin, B Banerjee, S Bantly, J Barberis, E Baringer, P Bartlett, JF Bassler, U Bean, A Belyaev, A Beri, SB Bernardi, G Bertram, I 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 Choudhary, BC Christenson, JH Chung, M Claes, D Clark, AR Cochran, J Coney, L Connolly, B Cooper, WE Coppage, D Cullen-Vidal, D Cummings, MAC Cutts, D Dahl, OI Davis, K De, K Del Signore, K Demarteau, M Denisov, D Denisov, SP Diehl, HT Diesburg, M Di Loreto, G Doulas, S Draper, P Ducros, Y Dudko, LV 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 Grannis, PD Green, JA Greenlee, H Grinstein, S Grudberg, P Grunendahl, S Guglielmo, G 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 Ito, AS Jerger, SA Jesik, R Joffe-Minor, T 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 Landsberg, G Leflat, A Lehner, F Li, J Li, QZ Lima, JGR Lincoln, D Linn, SL Linnemann, J Lipton, R Lu, JG Lucotte, A Lueking, L Lundstedt, C Maciel, AKA Madaras, RJ Manankov, V Mani, S 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 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 Piegaia, R Piekarz, H Pope, BG Popkov, E Prosper, HB Protopopescu, S Qian, J Quintas, PZ Raja, R Rajagopalan, S Reay, NW Reucroft, S 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 Song, XF 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 Thomas, TLT Thompson, J Toback, D Trippe, TG Turcot, AS Tuts, PM van Gemmeren, P Vaniev, V Van Kooten, R Varelas, N Volkov, AA Vorobiev, AP Wahl, HD Wang, H Warchol, J Watts, G Wayne, M Weerts, H White, A White, JT Whiteson, D Wightman, JA 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 DO Collaboration TI Search for R-parity violation in multilepton final states in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW D LA English DT Article ID GRAND UNIFICATION; TOP-QUARK; SUPERSYMMETRY; SUPERGRAVITY; MASS AB The result of a search for gaugino pair production with a trilepton signature is reinterpreted in the framework of minimal supergravity (MSUGRA) with R-parity violation via leptonic lambda Yukawa couplings. The search used 95 pb(-1) of p (p) over bar collisions at root s = 1.8 TeV recorded by the D empty set detector at the Fermilab Tevatron. A large domain of the MSUGRA parameter space is excluded for lambda(121), lambda(122)greater than or equal to 10(-4). C1 NYU, New York, NY 10003 USA. Univ Buenos Aires, 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. Acad Sci Czech Republ, Inst Phys, Prague, Czech Republic. Univ San Francisco Quito, Quito, Ecuador. Univ Grenoble 1, CNRS, IN2P3, Inst Sci Nucl, Grenoble, France. Univ Mediterranee, CNRS, IN2P3, CPPM, Marseille, France. Univ Paris 06, LPNHE, CNRS, IN2P3, Paris, France. Univ Paris 07, LPNHE, CNRS, IN2P3, Paris, France. CEA, Serv Phys Particules, DAPNIA, Saclay, France. Panjab Univ, Chandigarh 160014, India. Univ Delhi, Delhi 110007, India. Tata Inst Fundamental Res, Mumbai, India. Seoul Natl Univ, Seoul, South Korea. CINVESTAV, Mexico City 14000, DF, Mexico. Inst Phys Nucl, Krakow, Poland. Inst Theoret & Expt Phys, Moscow 117259, Russia. Moscow State Univ, Moscow, Russia. Inst High Energy Phys, Protvino, Russia. Univ Lancaster, Lancaster, England. Univ Arizona, Tucson, AZ 85721 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. 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 47408 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Kansas, Lawrence, KS 66045 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. 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), NYU, New York, NY 10003 USA. RI Shivpuri, R K/A-5848-2010; 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; Belyaev, Alexander/F-6637-2015; Kim, Sun Kee/G-2042-2015; Chekulaev, Sergey/O-1145-2015; Gutierrez, Phillip/C-1161-2011; Leflat, Alexander/D-7284-2012; Dudko, Lev/D-7127-2012; Merkin, Mikhail/D-6809-2012; Sznajder, Andre/L-1621-2016; Canelli, Florencia/O-9693-2016 OI Yip, Kin/0000-0002-8576-4311; Kuleshov, Sergey/0000-0002-3065-326X; De, Kaushik/0000-0002-5647-4489; Belyaev, Alexander/0000-0002-1733-4408; Kim, Sun Kee/0000-0002-0013-0775; Dudko, Lev/0000-0002-4462-3192; Sznajder, Andre/0000-0001-6998-1108; Canelli, Florencia/0000-0001-6361-2117 NR 31 TC 11 Z9 11 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 071701 DI 10.1103/PhysRevD.62.071701 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400005 ER PT J AU Abe, K Abe, K Abe, T Adam, I Akagi, T Akimoto, H Allen, NJ Ash, WW Aston, D Baird, KG Baltay, C Band, HR Barakat, MB Bardon, O Barklow, TL Bashindzhagyan, GL Bauer, JM Bellodi, G Benvenuti, AC Bilei, GM Bisello, D Blaylock, G Bogart, JR Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Byrne, RM Calcaterra, A Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A Cavalli-Sforza, M Chou, A Church, E Cohn, HO Coller, JA Convery, MR Cook, V Cowan, RF Coyne, DG Crawford, G Damerell, CJS Danielson, MN Daoudi, M de Groot, N Dell'Orso, R Dervan, PJ de Sangro, R Dima, M Dong, DN Doser, M Dubois, R Eisenstein, BI Erofeeva, I Eschenburg, V Etzion, E Fahey, S Falciai, D Fan, C Fernandez, JP Fero, MJ Flood, K Frey, R Gifford, J Gillman, T Gladding, G Gonzalez, S Goodman, ER Hart, EL Harton, JL Hasuko, K Hedges, SJ Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Huynh, X Hwang, H Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Kamyshkov, Y Kang, HJ Karliner, I Kawahara, H Kim, YD King, ME King, R Kofler, RR Krishna, NM Kroeger, RS Langston, M Lath, A Leith, DWG Lia, V Lin, C Liu, MX Liu, X Loreti, M Lu, A Lynch, HL Ma, J Mahjouri, M Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T Masuda, H Mazzucato, E McKemey, AK Meadows, BT Menegatti, C Messner, R Mockett, PM Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Nagamine, T Narita, S Nauenberg, U Neal, H Nussbaum, M Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, CH Pavel, TJ Peruzzi, I Piccolo, M Piemontese, L Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Reidy, J Reinertsen, PL Rensing, PE Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schumm, BA Schwiening, J Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Sherden, DJ Shmakov, KD Simopoulos, C Sinev, NB Smith, SR Smy, MB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, H Steiner, R Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Thom, J Torrence, E Toumbas, NK Usher, T Vannini, C Va'vra, J Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, DL Wagner, SR Waite, AP Walston, S Watts, SJ Weidemann, AW Weiss, ER Whitaker, JS White, SL Wickens, FJ Williams, B Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, M Word, GB Wright, TR Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yashima, J Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zhou, J AF Abe, K Abe, K Abe, T Adam, I Akagi, T Akimoto, H Allen, NJ Ash, WW Aston, D Baird, KG Baltay, C Band, HR Barakat, MB Bardon, O Barklow, TL Bashindzhagyan, GL Bauer, JM Bellodi, G Benvenuti, AC Bilei, GM Bisello, D Blaylock, G Bogart, JR Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Byrne, RM Calcaterra, A Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A Cavalli-Sforza, M Chou, A Church, E Cohn, HO Coller, JA Convery, MR Cook, V Cowan, RF Coyne, DG Crawford, G Damerell, CJS Danielson, MN Daoudi, M de Groot, N Dell'Orso, R Dervan, PJ de Sangro, R Dima, M Dong, DN Doser, M Dubois, R Eisenstein, BI Erofeeva, I Eschenburg, V Etzion, E Fahey, S Falciai, D Fan, C Fernandez, JP Fero, MJ Flood, K Frey, R Gifford, J Gillman, T Gladding, G Gonzalez, S Goodman, ER Hart, EL Harton, JL Hasuko, K Hedges, SJ Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Huynh, X Hwang, H Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Kamyshkov, Y Kang, HJ Karliner, I Kawahara, H Kim, YD King, ME King, R Kofler, RR Krishna, NM Kroeger, RS Langston, M Lath, A Leith, DWG Lia, V Lin, C Liu, MX Liu, X Loreti, M Lu, A Lynch, HL Ma, J Mahjouri, M Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T Masuda, H Mazzucato, E McKemey, AK Meadows, BT Menegatti, C Messner, R Mockett, PM Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Nagamine, T Narita, S Nauenberg, U Neal, H Nussbaum, M Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, CH Pavel, TJ Peruzzi, I Piccolo, M Piemontese, L Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Reidy, J Reinertsen, PL Rensing, PE Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schumm, BA Schwiening, J Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Sherden, DJ Shmakov, KD Simopoulos, C Sinev, NB Smith, SR Smy, MB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, H Steiner, R Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Thom, J Torrence, E Toumbas, NK Usher, T Vannini, C Va'vra, J Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, DL Wagner, SR Waite, AP Walston, S Watts, SJ Weidemann, AW Weiss, ER Whitaker, JS White, SL Wickens, FJ Williams, B Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, M Word, GB Wright, TR Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yashima, J Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zhou, J CA SLD Collaboration TI Search for charmless hadronic decays of B mesons with the SLAC SLD detector SO PHYSICAL REVIEW D LA English DT Article ID CP-VIOLATING ASYMMETRIES; NONLEPTONIC DECAYS; EVENTS; MULTIPLICITIES AB Based on a sample of approximately 500 000 hadronic Z(o) decays accumulated between 1993 and 1998, the SLD experiment has set limits on 24 fully charged two-body and quasi-two-body exclusive charmless hadronic decays of B(+), B(o), and B(s)(o) mesons. The precise tracking capabilities of the SLD detector provided for the efficient reduction of combinatoric backgrounds, yielding the most precise available limits for ten of these modes. C1 Nagoya Univ, Chikusa Ku, Nagoya, Aichi 464, Japan. Adelphi Univ, Garden City, NY 11530 USA. Aomori Univ, Aomori 030, Japan. Ist Nazl Fis Nucl, Sez Bologna, I-40126 Bologna, Italy. Univ Bristol, Bristol, Avon, England. Brunel Univ, Uxbridge UB8 3PH, Middx, England. Boston Univ, Boston, MA 02215 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. Univ Colorado, Boulder, CO 80309 USA. Columbia Univ, New York, NY 10533 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Univ Ferrara, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Sez Ferrara, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Illinois, Urbana, IL 61801 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Louisiana Tech Univ, Ruston, LA 71272 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Mississippi, University, MS 38677 USA. MIT, Cambridge, MA 02139 USA. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow 119899, Russia. Univ Oregon, Eugene, OR 97403 USA. Univ Oxford, Oxford OX1 3RH, England. Univ Padua, I-35100 Padua, Italy. Ist Nazl Fis Nucl, Sez Padova, I-35100 Padua, Italy. Univ Perugia, I-06100 Perugia, Italy. Ist Nazl Fis Nucl, Sez Perugia, I-06100 Perugia, Italy. Ist Nazl Fis Nucl, Sez Pisa, I-56010 Pisa, Italy. Univ Pisa, I-56010 Pisa, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Rutgers State Univ, Piscataway, NJ 08855 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Soongsil Univ, Seoul 156743, South Korea. Sogang Univ, Seoul, 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. Univ Victoria, Victoria, BC V8W 3P6, Canada. 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. RP Abe, K (reprint author), Nagoya Univ, Chikusa Ku, Nagoya, Aichi 464, Japan. RI de Groot, Nicolo/A-2675-2009; Stahl, Achim/E-8846-2011; de Sangro, Riccardo/J-2901-2012; Cavalli-Sforza, Matteo/H-7102-2015; Frey, Raymond/E-2830-2016; Kamyshkov, Yuri/J-7999-2016; Calcaterra, Alessandro/P-5260-2015 OI Stahl, Achim/0000-0002-8369-7506; de Sangro, Riccardo/0000-0002-3808-5455; Frey, Raymond/0000-0003-0341-2636; Kamyshkov, Yuri/0000-0002-3789-7152; Calcaterra, Alessandro/0000-0003-2670-4826 NR 28 TC 5 Z9 5 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 071101 DI 10.1103/PhysRevD.62.071101 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400001 ER PT J AU Afanasev, A Carlson, CE Wahlquist, C AF Afanasev, A Carlson, CE Wahlquist, C TI Scaling and duality in semiexclusive processes SO PHYSICAL REVIEW D LA English DT Article ID PERTURBATIVE QCD; FORM-FACTORS; MESON PHOTOPRODUCTION; EXCITED BARYONS; RESONANCES; SCATTERING; TRANSITION; MOMENTUM; ELECTROPRODUCTION; DISTRIBUTIONS AB We discuss extending scaling and duality studies to semiexclusive processes. We show that semiexclusive hard pion photoproduction should exhibit scaling behavior in kinematic regions where the photon and pion both interact directly with the same quark. We show that such kinematic regions exist. We also show that the constancy with changing momentum transfer of the resonance peak/scaling curve ratio, familiar for many resonances in deep inelastic scattering, is also expected in the semiexclusive case. C1 N Carolina Cent Univ, Dept Phys, Durham, NC 27707 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Coll William & Mary, Dept Phys, Nucl & Particle Theory Grp, Williamsburg, VA 23187 USA. RP N Carolina Cent Univ, Dept Phys, Durham, NC 27707 USA. NR 30 TC 8 Z9 8 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 074011 DI 10.1103/PhysRevD.62.074011 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400040 ER PT J AU Alexopoulos, T Anderson, EW Bismas, NN Bujak, A Carmony, DD Erwin, AR Findeisen, C Goshaw, AT Gulbrandsen, K Gutay, LJ Hirsch, AS Hojvat, C Jennings, JR Kenney, VP Lindsey, CS LoSecco, JM Morgan, N Nelson, K Oh, SH Porile, N Preston, L Scharenberg, R Stringfellow, B Thompson, M Turkot, F Walker, WD Wang, CH Warchol, J AF Alexopoulos, T Anderson, EW Bismas, NN Bujak, A Carmony, DD Erwin, AR Findeisen, C Goshaw, AT Gulbrandsen, K Gutay, LJ Hirsch, AS Hojvat, C Jennings, JR Kenney, VP Lindsey, CS LoSecco, JM Morgan, N Nelson, K Oh, SH Porile, N Preston, L Scharenberg, R Stringfellow, B Thompson, M Turkot, F Walker, WD Wang, CH Warchol, J CA Fermilab E375 Collaboration TI Cross sections for deuterium, tritium, and helium production in (p)over-barp collisions at root s=1.8 TeV SO PHYSICAL REVIEW D LA English DT Article ID ABUNDANCE; SPECTRUM; COLLIDER; ENERGY AB We present the results of a search for the production of Light elements in (p) over bar p collisions at the Fermilab Tevatron collider. Momentum, time of flight, and dE/dx measurements are used to distinguish nuclei from elementary particles. A production ratio for deuterium to hydrogen is calculated and compared to the primordial value of the big bang model. Some evidence for tritium is found and none for helium isotopes. C1 Univ Wisconsin, Madison, WI 53706 USA. Duke Univ, Durham, NC 27708 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Notre Dame, Notre Dame, IN 46556 USA. Purdue Univ, W Lafayette, IN 47907 USA. Royal Inst Technol, S-10405 Stockholm, Sweden. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Univ Virginia, Charlottesville, VA 22901 USA. RP Alexopoulos, T (reprint author), Univ Wisconsin, Madison, WI 53706 USA. NR 20 TC 4 Z9 4 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 072004 DI 10.1103/PhysRevD.62.072004 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400011 ER PT J AU Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, C Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V AF Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, C Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V CA CLEO Collaboration TI Resonance structure of tau(-)-> K-pi(+)pi(-)nu(tau) decays SO PHYSICAL REVIEW D LA English DT Article ID 3-PRONG TAU-DECAYS; CHARGED KAONS; MESONS; PHYSICS AB Using a sample of 4.7 fb(-1) integrated luminosity accumulated with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we investigate the mass spectrum and resonant structure in tau(-) -->K(-)pi(+)pi(-) nu(tau) decays. We measure the relative fractions of K-1(1270) and K-1(1400) resonances in these decays, as well as the K-1 masses and widths. Our fitted K-1 resonances are somewhat broader than previous hadroproduction measurements, and in agreement with recent CERN LEP results from tau decay. The larger central value of our measured width supports models which attribute the small tau(-) --> K- pi(+) pi(-) nu(tau) branching fraction to larger K-1 widths than are presently tabulated. We also determine the K-a-K-b mixing angle theta(K). C1 Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Montreal, PQ, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Texas Pan Amer, Edinburg, TX 78539 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Cincinnati, Cincinnati, OH 45221 USA. MIT, Cambridge, MA 02139 USA. RP Asner, DM (reprint author), Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 22 TC 18 Z9 18 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 072006 DI 10.1103/PhysRevD.62.072006 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400013 ER PT J AU Bai, JZ Ban, Y Bian, JG Blum, I Chen, AD Chen, GP Chen, HF Chen, HS Chen, J Chen, JC Chen, XD Chen, Y Chen, YB Cheng, BS Choi, JB Cui, XZ Ding, HL Dong, LY Du, ZZ Dunwoodie, W Gao, CS Gao, ML Gao, SQ Gratton, P Gu, JH Gu, SD Gu, WX Guo, YN Guo, ZJ Han, SW Han, Y Harris, FA He, J He, JT He, KL He, M Heng, YK Hitlin, DG Hu, GY Hu, HM Hu, JL Hu, QH Hu, T Huang, GS Huang, XP Huang, YZ Izen, JM Jiang, CH Jin, Y Jones, BD Ju, X Kang, JS Ke, ZJ Kelsey, MH Kim, BK Kim, HJ Kim, SK Kim, TY Kong, D Lai, YF Lang, PF Lankford, A Li, CG Li, D Li, HB Li, J Li, JC Li, PQ Li, W Li, WG Li, XH Li, XN Li, XQ Li, ZC Liu, B Liu, F Liu, F Liu, HM Liu, J Liu, JP Liu, RG Liu, Y Liu, ZX Lou, XC Lowery, B Lu, GR Lu, F Lu, JG Luo, XL Ma, EC Ma, JM Malchow, R Mao, HS Mao, ZP Meng, XC Mo, XH Nie, J Olsen, SL Oyang, J Paluselli, D Pan, LJ Panetta, J Park, H Porter, F Qi, ND Qi, XR Qian, CD Qiu, JF Qu, YH Que, YK Rong, G Schernau, M Shao, YY Shen, BW Shen, DL Shen, H Shen, HY Shen, XY Shi, F Shi, HZ Song, XF Standifird, J Suh, JY Sun, HS Sun, LF Sun, YZ Tang, SQ Toki, W Tong, GL Varner, GS Wang, F Wang, L Wang, LS Wang, LZ Wang, P Wang, PL Wang, SM Wang, YY Wang, ZY Weaver, M Wei, CL Wu, N Wu, YG Xi, DM Xia, XM Xie, Y Xie, YH Xu, GF Xue, ST Yan, J Yan, WG Yang, CM Yang, CY Yang, HX Yang, W Yang, XF Ye, MH Ye, SW Ye, YX Yu, CS Yu, CX Yu, GW Yu, YH Yu, ZQ Yuan, CZ Yuan, Y Zhang, BY Zhang, C Zhang, CC Zhang, DH Zhang, DH Zhang, HL Zhang, J Zhang, JW Zhang, L Zhang, L Zhang, LS Zhang, P Zhang, QJ Zhang, SQ Zhang, XY Zhang, YY Zhao, DX Zhao, HW Zhao, JW Zhao, JW Zhao, M Zhao, WR Zhao, ZG Zheng, JP Zheng, LS Zheng, YH Zheng, ZP Zhou, BQ Zhou, L Zhu, KJ Zhu, QM Zhu, YC Zhu, YS Zhu, ZA Zhuang, BA AF Bai, JZ Ban, Y Bian, JG Blum, I Chen, AD Chen, GP Chen, HF Chen, HS Chen, J Chen, JC Chen, XD Chen, Y Chen, YB Cheng, BS Choi, JB Cui, XZ Ding, HL Dong, LY Du, ZZ Dunwoodie, W Gao, CS Gao, ML Gao, SQ Gratton, P Gu, JH Gu, SD Gu, WX Guo, YN Guo, ZJ Han, SW Han, Y Harris, FA He, J He, JT He, KL He, M Heng, YK Hitlin, DG Hu, GY Hu, HM Hu, JL Hu, QH Hu, T Huang, GS Huang, XP Huang, YZ Izen, JM Jiang, CH Jin, Y Jones, BD Ju, X Kang, JS Ke, ZJ Kelsey, MH Kim, BK Kim, HJ Kim, SK Kim, TY Kong, D Lai, YF Lang, PF Lankford, A Li, CG Li, D Li, HB Li, J Li, JC Li, PQ Li, W Li, WG Li, XH Li, XN Li, XQ Li, ZC Liu, B Liu, F Liu, F Liu, HM Liu, J Liu, JP Liu, RG Liu, Y Liu, ZX Lou, XC Lowery, B Lu, GR Lu, F Lu, JG Luo, XL Ma, EC Ma, JM Malchow, R Mao, HS Mao, ZP Meng, XC Mo, XH Nie, J Olsen, SL Oyang, J Paluselli, D Pan, LJ Panetta, J Park, H Porter, F Qi, ND Qi, XR Qian, CD Qiu, JF Qu, YH Que, YK Rong, G Schernau, M Shao, YY Shen, BW Shen, DL Shen, H Shen, HY Shen, XY Shi, F Shi, HZ Song, XF Standifird, J Suh, JY Sun, HS Sun, LF Sun, YZ Tang, SQ Toki, W Tong, GL Varner, GS Wang, F Wang, L Wang, LS Wang, LZ Wang, P Wang, PL Wang, SM Wang, YY Wang, ZY Weaver, M Wei, CL Wu, N Wu, YG Xi, DM Xia, XM Xie, Y Xie, YH Xu, GF Xue, ST Yan, J Yan, WG Yang, CM Yang, CY Yang, HX Yang, W Yang, XF Ye, MH Ye, SW Ye, YX Yu, CS Yu, CX Yu, GW Yu, YH Yu, ZQ Yuan, CZ Yuan, Y Zhang, BY Zhang, C Zhang, CC Zhang, DH Zhang, DH Zhang, HL Zhang, J Zhang, JW Zhang, L Zhang, L Zhang, LS Zhang, P Zhang, QJ Zhang, SQ Zhang, XY Zhang, YY Zhao, DX Zhao, HW Zhao, JW Zhao, JW Zhao, M Zhao, WR Zhao, ZG Zheng, JP Zheng, LS Zheng, YH Zheng, ZP Zhou, BQ Zhou, L Zhu, KJ Zhu, QM Zhu, YC Zhu, YS Zhu, ZA Zhuang, BA CA BES Collaboration TI Measurement of the mass and full width of the eta(c) meson SO PHYSICAL REVIEW D LA English DT Article ID DECAYS; STATE AB In a sample of 7.8 million J/psi decays collected in the Beijing Spectrometer, the process J/psi --> gamma eta(c) is observed for live different eta(c) decay channels: K+ K- pi(+)pi(-), pi(+)pi(-)pi(+)pi(-), K+/- K(s)(o)pi(-/+) (with K-s(o) --> pi(+)pi(-)), phi phi (with phi-->K+K-) and K(+)K(-)pi(o). From these signals, we determine the mass of eta(c) to be 2976.6+/-2.9 +/- 1.3 MeV. Combining this result with a previously reported result from a similar study using psi(2S)-->gamma eta(c) detected in the same spectrometer gives m(eta c) = 2976.3 +/- 2.3 +/- 1.2 MeV. For the combined samples, we obtain Gamma(eta c) = 11.0 +/- 8.1 +/- 4.1 MeV. C1 Inst High Energy Phys, Beijing 100039, Peoples R China. CALTECH, Pasadena, CA 91125 USA. Chinese Ctr Adv Sci & Technol, Beijing 100087, Peoples R China. Chonbuk Natl Univ, Chonju 561756, South Korea. Colorado State Univ, Ft Collins, CO 80523 USA. Hangzhou Univ, Hangzhou 310028, Peoples R China. Henan Normal Univ, Xinxiang 453002, Peoples R China. Huazhong Normal Univ, Wuhan 430079, Peoples R China. Korea Univ, Seoul 136701, South Korea. Nankai Univ, Tianjin 300071, Peoples R China. Peking Univ, Beijing 100871, Peoples R China. Shandong Univ, Jinan 250100, Peoples R China. Shanghai Jiao Tong Univ, Shanghai 200030, Peoples R China. Seoul Natl Univ, Seoul 151742, South Korea. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Hawaii, Honolulu, HI 96822 USA. Univ Calif Irvine, Irvine, CA 92717 USA. Univ Sci & Technol China, Hefei 230026, Peoples R China. Univ Texas, Richardson, TX 75083 USA. Wuhan Univ, Wuhan 430072, Peoples R China. RP Bai, JZ (reprint author), Inst High Energy Phys, Beijing 100039, Peoples R China. RI Chen, Yu/E-3788-2012; Kim, Sun Kee/G-2042-2015 OI Kim, Sun Kee/0000-0002-0013-0775 NR 12 TC 17 Z9 18 U1 1 U2 7 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 OCT 1 PY 2000 VL 62 IS 7 AR 072001 DI 10.1103/PhysRevD.62.052001 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400008 ER PT J AU Balitsky, I Kuchina, E AF Balitsky, I Kuchina, E TI Deeply virtual Compton scattering at small x SO PHYSICAL REVIEW D LA English DT Article ID OPERATOR EXPANSION; QCD; ELECTROPRODUCTION; FACTORIZATION; DISTRIBUTIONS; NUCLEON; HERA AB We calculate the cross section of deeply virtual Compton scattering at large energies and intermediate momentum transfers. C1 Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Theory Grp, Newport News, VA 23606 USA. RP Balitsky, I (reprint author), Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. EM balitsky@jlab.org; kuchina@jlab.org NR 34 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 074004 DI 10.1103/PhysRevD.62.074004 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400033 ER PT J AU Barger, V Geer, S Raja, R Whisnant, K AF Barger, V Geer, S Raja, R Whisnant, K TI Neutrino oscillations at an entry-level neutrino factory and beyond SO PHYSICAL REVIEW D LA English DT Review ID GEV ENERGY-RANGE; CP VIOLATION; ATMOSPHERIC NEUTRINOS; PARAMETRIC-RESONANCE; SUPER-KAMIOKANDE; VACUUM OSCILLATION; SOLAR NEUTRINOS; LSND EXPERIMENT; MASS MATRICES; T VIOLATION AB We consider the parameters of an entry-level neutrino factory designed to make the first observation of nu(e) --> nu(mu) oscillations, measure the corresponding amplitude sin(2)2 theta(13), and determine the sign of the atmospheric-scale delta m(32)(2) via matter effects. A 50 kt detector, a stored muon energy E(mu)greater than or equal to 20 GeV and 10(19) moon decays would enable these goals to be met provided sin(2)2 theta(13)>0.01. The determination of the sign of delta m(32)(2) also requires a baseline L greater than or equal to 2000 km. An upgraded neutrino factory with O(10(20)) decays would enable the first observation of nu(e) --> nu(tau) oscillations. With O(10(21)) decays the effects of a large CP phase could be measured in the case of the large angle matter oscillation solution to the solar neutrino anomaly. Our analysis includes a family of three-neutrino models that can account for the atmospheric and solar neutrino oscillation indications. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. NR 109 TC 58 Z9 58 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 073002 DI 10.1103/PhysRevD.62.073002 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400016 ER PT J AU Bhat, PC Gilmartin, R Prosper, HB AF Bhat, PC Gilmartin, R Prosper, HB TI Strategy for discovering a low-mass Higgs boson at the Fermilab Tevatron SO PHYSICAL REVIEW D LA English DT Article ID PHYSICS AB We have studied the potential of the CDF and DO experiments to discover a low-mass standard model Higgs boson, during run II, via the processes p (p) over bar --> WH --> lvb (b) over bar, p (p) over bar --> ZH --> l(+)l(-)b (b) over bar and p (p) over bar --> ZH --> v (v) over bar b (b) over bar. We show that a multivariate analysis using neural networks that exploits all the information contained within a set of event variables leads to a significant reduction, with respect to any equivalent conventional analysis, in the integrated luminosity required to find a standard model Higgs boson in the mass range 90 GeV/c(2) < M-H < 130 GeV/c(2). The luminosity reduction is sufficient to bring the discovery of the Higgs boson within reach of the Fermilab Tevatron experiments, given the anticipated integrated luminosities of run II, whose scope has recently been expanded. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Bhat, PC (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 26 TC 12 Z9 12 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 074022 DI 10.1103/PhysRevD.62.074022 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400051 ER PT J AU Briere, RA Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lorenc, J Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Jain, V McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, TK AF Briere, RA Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lorenc, J Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Jain, V McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, TK CA CLEO Collaboration TI Measurements of charm fragmentation into D-s(*+) and D-s(+) in e(+)e(-) annihilations at root s=10.5 GeV SO PHYSICAL REVIEW D LA English DT Article ID LUND MONTE-CARLO; JET FRAGMENTATION; E+E-PHYSICS; Z-DECAYS; MESONS; MODEL AB A study of charm fragmentation into D-s(*+) and D-s(+) in e(+)e(-) annihilations at root s = 10.5 GeV is presented. This study using 4.72 +/- 0.05 fb(-1) of CLEO II data reports measurements of the cross sections sigma(D-s(*+))) and sigma(D-s(+)) in momentum regions above x = 0.44, where x is the D-s momentum divided by the maximum kinematically allowed D-s momentum. The D-s vector to vector plus pseudoscalar production ratio is measured to be P-v(x(D-s(+)) > 0.44) = 0.44 +/- 0.04. C1 Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Montreal, PQ, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Texas Pan Amer, Edinburgh, TX 78539 USA. Yonsei Univ, Seoul 120749, South Korea. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. RP Briere, RA (reprint author), Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 22 TC 7 Z9 7 U1 1 U2 5 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 OCT 1 PY 2000 VL 62 IS 7 AR 072003 DI 10.1103/PhysRevD.62.072003 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400010 ER PT J AU Diehl, M Gousset, T Pire, B AF Diehl, M Gousset, T Pire, B TI Exclusive production of pion pairs in gamma*gamma collisions at large Q(2) SO PHYSICAL REVIEW D LA English DT Article ID LOWEST-ORDER CALCULATIONS; TRANSITION FORM-FACTOR; ELECTRON-POSITRON COLLISIONS; MONTE-CARLO SIMULATION; WAVE-FUNCTIONS; QUANTUM CHROMODYNAMICS; PARTON DISTRIBUTIONS; ASYMPTOTIC-BEHAVIOR; EVOLUTION-EQUATIONS; 2-PHOTON PROCESSES AB We perform a QCD analysis of the exclusive production of two mesons in gamma*gamma collisions in the kinematical domain of large photon virtuality Q and small hadronic invariant mass W. This reaction is dominated by a scale invariant mechanism which factorizes into a perturbative subprocess gamma*gamma-->q (q) over bar or gamma*y-->gg and a generalized two-meson distribution amplitude. We develop in detail the phenomenology of this process at e(+)e(-) colliders. Using a simple model for the two-pion distribution amplitude, based on its general properties, we estimate the cross section for the kinematics accessible at BABAR, BELLE, CLEO, and CERN LEP. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. SUBATECH, F-44307 Nantes, France. Ecole Polytech, CPhT, F-91128 Palaiseau, France. RP Diehl, M (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Pire, Bernard/I-3994-2013 NR 51 TC 96 Z9 97 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 OCT 1 PY 2000 VL 62 IS 7 AR 073014 DI 10.1103/PhysRevD.62.073014 PG 28 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400028 ER PT J AU Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Brabant, P Cervantes, M Kravchenko, I Stutz, RP Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Lorenc, J Pedlar, TK Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F AF Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Brabant, P Cervantes, M Kravchenko, I Stutz, RP Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Lorenc, J Pedlar, TK Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F CA CLEO Collaboration TI Measurement of B(Lambda(+)(c)-> pK(-)pi(+)) SO PHYSICAL REVIEW D LA English DT Article ID CLEO-II DETECTOR; BARYON PRODUCTION; B-DECAY; PHYSICS AB The Lambda(c)(+)-->pK(-)pi(+) yield has been measured in a sample of two-jet continuum events containing both a charm tag ("(D) over bar") as well as an antiproton (e(+)e(-) --> (D) over bar (p) over bar X), with the antiproton in the hemisphere opposite the (D) over bar (measurement of charge conjugate modes is implicit throughout). Under the hypothesis that such selection criteria tag e(+)e(-)-->(D) over bar (p) over bar Lambda(c)(+)X events, the Lambda(c)(+)-->pK(-)pi(+) branching fraction can be determined by measuring the pK(-)pi(+) yield in the same hemisphere as the antiprotons in our (D) over bar (p) over bar X sample. Three types of (D) over bar charm tags are used, pi(soft)(-) (from D*- --> (D) over bar(o) pi(soft)(-) electrons (from (D) over bar-->Xe- nu), and fully reconstructed (D) over bar(o) --> K+ pi(-) or D- -->K+ pi(-)pi(-) or D-s(-) --> phi pi(-). Combining our results obtained from the three independent charm tags, we obtain B(Lambda(c)(+) --> pK(-) pi(+)) = (5.0 +/- 0.5 +/- 1.2)%. C1 Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Ottawa, ON, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Texas Pan Amer, Edinburg, TX 78539 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Cincinnati, Cincinnati, OH 45221 USA. MIT, Cambridge, MA 02139 USA. RP Jaffe, DE (reprint author), Univ Calif San Diego, La Jolla, CA 92093 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 21 TC 12 Z9 12 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 072005 DI 10.1103/PhysRevD.62.072005 PG 18 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400012 ER PT J AU Jenkins, E Lebed, RF AF Jenkins, E Lebed, RF TI Naturalness of the Coleman-Glashow mass relation in the 1/N-c expansion: An update SO PHYSICAL REVIEW D LA English DT Article ID LARGE N-QCD; HEAVY-QUARK; C BARYONS; SPLITTINGS AB A new measurement of the Xi(0) mass verifies the accuracy of the Coleman-Glashow relation at the level predicted by the 1/N-c expansion. Values for other baryon isospin mass splittings are updated, and continue to agree with the 1/N-c hierarchy. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Jenkins, E (reprint author), Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. EM ejenkins@ucsd.edu; lebed@jlab.org NR 12 TC 17 Z9 17 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 077901 DI 10.1103/PhysRevD.62.077901 PG 2 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400088 ER PT J AU Lietti, SM Murayama, H AF Lietti, SM Murayama, H TI CP violating Zt(t)over-bar and gamma t(t)over-bar couplings at a future e(+)e(-) collider SO PHYSICAL REVIEW D LA English DT Article ID SUPERSYMMETRIC STANDARD MODEL; QUARK PAIR PRODUCTION; WEAK DIPOLE-MOMENT; TOP-QUARK; E+E COLLISIONS; HIGGS SECTOR; POLARIZATION; DOUBLETS; PHYSICS; MASS AB The effect of new operators that give rise to CP-violating couplings of the type Zt (t) over bar and gamma t (t) over bar are examined at future electron positron linear colliders (FLC). The impact of these CP violating interactions over standard model predictions was studied for the process e(+)e(-) --> t (t) over bar with the subsequent decays t --> bl(+)nu(l) and (t) over bar --> (b) over bar l(-)v<(nu)over bar>(l), called the dilepton mode, and t --> bl(+)v(l) and (t) over bar --> <(bq)over bar>q' or t --> bq (q) over bar and (t) over bar --> (b) over bar l(-)<(nu)over bar>(l), called the single lepton mode, where the final leptons an l(+/-) = e(+/-) or mu(+/-), and the final quarks are q(q') = u(d) or c(s). A polarized electron beam and CP observables and asymmetries are used to impose bounds on the anomalous couplings. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Lietti, SM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. RI Murayama, Hitoshi/A-4286-2011 NR 33 TC 1 Z9 1 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 074003 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400032 ER PT J AU Matchev, KT Thomas, S AF Matchev, KT Thomas, S TI Higgs and Z-boson signatures of supersymmetry SO PHYSICAL REVIEW D LA English DT Article ID GAMMA-GAMMA COUPLINGS; P(P)OVER-BAR COLLISIONS; FERMILAB TEVATRON; ROOT-S=1.8 TEV; BREAKING; LIMITS; SEARCH; ENERGY; MODELS AB In supersymmetric theories of nature the Higgsino fermionic superpartner of the Higgs boson can arise as the lightest standard model superpartner depending on the couplings between the Higgs and supersymmetry breaking sectors. In this Brief Report the production and decay of Higgsino pairs to the Goldstone fermion of supersymmetry breaking and the Higgs boson h, or gauge bosons Z or gamma are considered. Relatively clean diboson final states hh, h gamma, hZ, Z gamma, or ZZ with a large amount of missing energy result. The latter channels provide novel discovery modes for supersymmetry at high energy colliders since events with Z bosons are generally rejected in supersymmetry searches. In addition, final states with real Higgs bosons can potentially provide efficient channels to discover and study a Higgs signal at the Fermilab Tevatron run II. C1 Fermilab Natl Accelerator Lab, Dept Theoret Phys, Batavia, IL 60510 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RP Fermilab Natl Accelerator Lab, Dept Theoret Phys, POB 500, Batavia, IL 60510 USA. NR 16 TC 32 Z9 32 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD OCT 1 PY 2000 VL 62 IS 7 AR 077702 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 361XK UT WOS:000089749400087 ER PT J AU Chang, SC Shrock, R AF Chang, SC Shrock, R TI Ground-state entropy of the Potts antiferromagnet with next-nearest-neighbor spin-spin couplings on strips of the square lattice SO PHYSICAL REVIEW E LA English DT Article ID CHROMATIC POLYNOMIALS; ASYMPTOTIC LIMITS; LOWER BOUNDS; GRAPHS; DEGENERACY; FAMILIES; MODELS; SERIES AB We present exact calculations of the zero-temperature partition function (chromatic polynomial) and W(q), the exponent of the ground-state entropy, for the q-state Potts antiferromagnet with next-nearest-neighbor spin-spin couplings on square lattice strips, of width L-y=3 and L-y=4 vertices and arbitrarily great length L-x vertices, with both free and periodic boundary conditions. The resultant values of W for a range of physical q values are compared with each other and with the values for the full two-dimensional lattice. These results give insight into the effect of such nonnearest-neighbor couplings on the ground-state entropy. We show that the q=2 (Ising) and q=4 Potts antiferromagnets have zero-temperature critical points on the L-x-->infinity limits of the strips that we study. With the generalization of q from Z(+) to C, we determine the analytic structure of W(q) in the q plane for the various cases. C1 SUNY Stony Brook, CN Yang Inst Theoret Phys, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11793 USA. RP Chang, SC (reprint author), SUNY Stony Brook, CN Yang Inst Theoret Phys, Stony Brook, NY 11794 USA. NR 48 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 2000 VL 62 IS 4 BP 4650 EP 4664 DI 10.1103/PhysRevE.62.4650 PN A PG 15 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 365XY UT WOS:000089976800026 ER PT J AU Wei, X Hong, SC Zhuang, XW Goto, T Shen, YR AF Wei, X Hong, SC Zhuang, XW Goto, T Shen, YR TI Nonlinear optical studies of liquid crystal alignment on a rubbed polyvinyl alcohol surface SO PHYSICAL REVIEW E LA English DT Article ID SUM-FREQUENCY GENERATION; UNRUBBED POLYIMIDE FILMS; MOLECULAR-ORIENTATION; 2ND-HARMONIC GENERATION; FORCE MICROSCOPY; PRETILT ANGLE; POLYMER; SPECTROSCOPY; SILANE; CONFORMATION AB Sum-frequency vibrational spectroscopy and second-harmonic generation have been used to measure the orientational distributions of the polymer chains and adsorbed 8CB liquid crystal molecules on a rubbed polyvinyl alcohol surface. Results show that the polymer chains at the surface appear to be well aligned by rubbing, and the adsorbed liquid crystal molecules are aligned, in turn, by the surface polymer chains. Strong correlation exists between the orientational distributions of the polymer chains and the liquid crystal molecules, indicating that the surface-induced bulk alignment of a liquid crystal film by rubbed polymer surfaces is via an orientational epitaxylike mechanism. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP Wei, X (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 50 TC 170 Z9 171 U1 4 U2 49 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD OCT PY 2000 VL 62 IS 4 BP 5160 EP 5172 DI 10.1103/PhysRevE.62.5160 PN A PG 13 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 365XY UT WOS:000089976800086 ER PT J AU Wu, JZ Bratko, D Blanch, HW Prausnitz, JM AF Wu, JZ Bratko, D Blanch, HW Prausnitz, JM TI Interaction between oppositely charged micelles or globular proteins SO PHYSICAL REVIEW E LA English DT Article ID HIGHLY ASYMMETRIC ELECTROLYTES; DOUBLE-LAYER INTERACTIONS; HYPERNETTED-CHAIN; ELECTROSTATIC INTERACTION; MONTE-CARLO; COLLOIDAL PARTICLES; INTEGRAL-EQUATION; IONIC COLLOIDS; ATTRACTION; FORCES AB Monte Carlo simulations and the hypernetted chain theory are used to study the interaction between spherical macroions of opposite charge immersed in a solution of monovalent or divalent simple electrolyte. These calculations represent the first step toward studying phase behavior and precipitation kinetics in solutions containing a mixture of macroions with positive and negative net charges. The potential of mean force between colloidal particles is determined as a function of colloid-colloid separation. In addition to having an opposite sign, the calculated potential of mean force is found to be stronger and longer-ranged than observed in the case of equally charged macroparticles. The difference is more pronounced in the presence of divalent counterions and is especially noticeable when we compare distinct Coulombic and hard-core collision contributions to the interaction between equally and oppositely charged colloids. The present observations suggest the dominance of attractive forces between globally neutral but electrostatically heterogeneous macroparticles. While our numerical results cannot be successfully analyzed by existing theories, they provide useful guidance and benchmark data for the development of advanced analytic descriptions. 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 Wu, JZ (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RI Wu, Jianzhong/I-5164-2013; OI Wu, Jianzhong/0000-0002-4582-5941 NR 57 TC 34 Z9 34 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 2000 VL 62 IS 4 BP 5273 EP 5280 DI 10.1103/PhysRevE.62.5273 PN B PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 365YA UT WOS:000089977000011 PM 11089089 ER PT J AU Pretzler, G Schlegel, T Fill, E Eder, D AF Pretzler, G Schlegel, T Fill, E Eder, D TI Hot-electron generation in copper and photopumping of cobalt SO PHYSICAL REVIEW E LA English DT Article ID X-RAY SOURCE; LASER-PLASMA INTERACTIONS; SOLID TARGETS; K-ALPHA; OBLIQUE-INCIDENCE; INTENSITY; TRANSPORT; DIFFRACTION; ABSORPTION; EMISSION AB Hot electrons generated upon interaction of p-polarized 130 fs laser pulses with copper and penetrating into the target material are characterized with respect to their energy distribution and directionality. "Experimental" data are obtained by comparing the rear-side x-ray emission from layered targets with Monte Carlo electron-photon transport simulations. Theoretical electron energy distributions are derived by means of a one and a half-dimensional particle-in-cell code. Both sets of data consist of a two-temperature distribution of electrons propagating in a direction almost perpendicular to the target surface. The "experimental" data contain a considerably higher population of the lower temperature electrons. The discrepancy is explained by the intensity distribution of the laser spot. The results are used to design an experiment for demonstrating photopumping: of cobalt with copper K alpha radiation. A 10 mum copper foil is backed with 1 mm of polyethylene (PE) followed by 10 mum of cobalt, the rear-side K alpha emission of which is measured. The PE layer prevents fast electrons from reaching the cobalt. Comparing the cobalt K alpha emission with that of nickel, which is not photopumped by copper K alpha shows enhancement by almost a factor of 2. C1 Max Planck Inst Quantenopt, D-85748 Garching, Germany. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Pretzler, G (reprint author), Max Planck Inst Quantenopt, D-85748 Garching, Germany. NR 36 TC 24 Z9 24 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 2000 VL 62 IS 4 BP 5618 EP 5623 DI 10.1103/PhysRevE.62.5618 PN B PG 6 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 365YA UT WOS:000089977000042 ER PT J AU Lushnikov, PM Saffman, M AF Lushnikov, PM Saffman, M TI Collapse in a forced three-dimensional nonlinear Schrodinger equation SO PHYSICAL REVIEW E LA English DT Article ID WAVE COLLAPSE; SOLITONS; STABILITY; DRIVEN; PLASMAS AB We derive sufficient conditions for the occurrence of collapse in a forced three-dimensional nonlinear Schrodinger equation without dissipation. Numerical studies continue the results to the case of finite dissipation. C1 LD Landau Theoret Phys Inst, Moscow 117334, Russia. Riso Natl Lab, Opt & Fluid Dynam Dept, DK-4000 Roskilde, Denmark. RP Los Alamos Natl Lab, Div Theoret, MS-B284, Los Alamos, NM 87545 USA. RI Lushnikov, Pavel/I-2304-2013; Saffman, Mark/A-8120-2009 OI Saffman, Mark/0000-0001-6398-2097 NR 21 TC 12 Z9 12 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD OCT PY 2000 VL 62 IS 4 BP 5793 EP 5796 DI 10.1103/PhysRevE.62.5793 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 365YA UT WOS:000089977000061 ER PT J AU Triolo, A Triolo, F Lo Celso, F Betts, DE McClain, JB DeSimone, JM Wignall, GD Triolo, R AF Triolo, A Triolo, F Lo Celso, F Betts, DE McClain, JB DeSimone, JM Wignall, GD Triolo, R TI Critical micellization density: A small-angle-scattering structural study of the monomer-aggregate transition of block copolymers in supercritical CO2 SO PHYSICAL REVIEW E LA English DT Article ID CARBON-DIOXIDE; INTERACTION PARAMETERS; NEUTRON-SCATTERING AB In this paper we report a small-angle neutron-scattering investigation of micelle formation by the fluorocarbon-hydrocarbon block copolymer, polyvinyl acetate-b-poly (1,1,2,2-tetrahydroperfluoro-octyl acrylate) in supercritical CO2 (scCO(2)) at 313 K. At high pressure the copolymer is in a monomeric state with a random coil structure, while at low pressure the polymer forms spherical aggregates stable in a wide range of thermodynamic conditions. By profiling pressure, a sharp monomer-micelle transition is obtained due to the tuning of the solvating ability of scCO(2). We confirm the previous finding that this aggregate-monomer transition is driven by the gradual penetration of CO2 molecules toward the core of the aggregate and is critically related to the density of the solvent, thus giving additional support to the concept of a critical micellization density reported earlier on a similar polymer. C1 Univ Palermo, Dipartimento Chim Fis, I-90123 Palermo, Italy. HMI, Berlin, Germany. Mt Sinai Sch Med, New York, NY USA. Univ N Carolina, Dept Chem, Chapel Hill, NC 27514 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Triolo, A (reprint author), Univ Palermo, Dipartimento Chim Fis, I-90123 Palermo, Italy. RI Lo Celso, Fabrizio/B-7554-2012; Triolo, Alessandro/A-4431-2012; OI Triolo, Alessandro/0000-0003-4074-0743; Wignall, George/0000-0002-3876-3244 NR 18 TC 22 Z9 22 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 2000 VL 62 IS 4 BP 5839 EP 5842 DI 10.1103/PhysRevE.62.5839 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 365YA UT WOS:000089977000067 ER PT J AU Chiu, C Cheshkov, S Tajima, T AF Chiu, C. Cheshkov, S. Tajima, T. TI High energy laser-wakefield collider with synchronous acceleration SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article AB A recent study on a high energy accelerator system which involves multistage laser wakefield acceleration shows that the system is very sensitive to jitters due to misalignment between the beam and the wakefield. In particular, the effect of jitters in the presence of a strong focusing wakefield and initial phase space spread of the beam leads to severe emittance degradation of the beam. One way to improve the emittance control is to mitigate the wakefield by working with a plasma channel. However, there are limitations in this approach. Our present investigation does not involve a plasma channel. Instead of averaging over the full phase range of the quarter-wave acceleration, we treat the phase range as a variable. We have found that, for a fixed final acceleration energy and a small phase slip, the final emittance is inversely proportional to the total number of stages. This leads us to consider an accelerator system which consists of superunits, where each superunit consists of closely spaced short tubes, or chips, with the wakefield of each chip being created by an independent laser pulse. There is a relatively large gap between adjacent superunits. With this arrangement the beam electrons are accelerated with a small phase slip; i.e., the phase of the beam is approximately synchronous with respect to the wakefield. This system is designed to have resilience against jitters. It has its practical limitations. We also consider a "horn model" with an exact synchronous acceleration based on a scheme suggested by Katsouleas. Computer simulation of both the chip model and the horn model confirms an expected (sin psi)(3/2) law for emittance degradation in the small phase angle region. Thus the choice of a small loading phase together with a small phase slip provides another important ingredient in controlling emittance degradation. C1 [Chiu, C.; Cheshkov, S.; Tajima, T.] Univ Texas Austin, Dept Phys, Austin, TX 78712 USA. [Tajima, T.] Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Chiu, C (reprint author), Univ Texas Austin, Dept Phys, Austin, TX 78712 USA. FU U.S. Department of Energy (DOE); Japan Atomic Energy Research Institute (JAERI); U.S. DOE [W-7405-Eng.48] FX We thank Mike Downer and his Femtosecond Spectroscopy Group, especially Andy Rundquist and Erhard Gaul for valuable discussions. We also thank Boris Breizman for discussions on fluid dynamics related issues and George Sudarshan for discussions on the stochastic theory. This work is supported in part by the U.S. Department of Energy (DOE) and the Japan Atomic Energy Research Institute (JAERI). One of us (T.T.) is also supported in part through a U.S. DOE Contract No. W-7405-Eng.48 to Lawrence Livermore National Laboratory. NR 22 TC 18 Z9 20 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD OCT PY 2000 VL 3 IS 10 AR 101301 DI 10.1103/PhysRevSTAB.3.101301 PG 16 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V26ZO UT WOS:000208583700003 ER PT J AU Fung, KM Ball, M Chu, CM Hamilton, B Lee, SY Ng, KY AF Fung, K. M. Ball, M. Chu, C. M. Hamilton, B. Lee, S. Y. Ng, K. Y. TI Bunch length compression manipulations SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article AB Bunch length compression of a single proton bunch is studied by manipulations of the rf voltage and phase. Analytical expressions for the compression ratio, defined as the ratio of the initial to the final bunch lengths, are derived for a linear model. Results obtained from numerical simulations are compared with experimental results. The ultimate maximum compression ratios are found to be root 2/root 3 sigma(phi,i) for the phase shift method and root 8/root 3 pi sigma(phi,i) for the voltage manipulation method, where sigma(phi,i) is the rms rf-phase spread of the initial beam bunch at the maximum rf voltage. Effects of space charge force are also studied. C1 [Fung, K. M.; Ball, M.; Chu, C. M.; Hamilton, B.; Lee, S. Y.] Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. [Ng, K. Y.] Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. RP Fung, KM (reprint author), Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. FU U.S. Department of Energy Grant [DE-FG02-92ER40747]; National Science Foundation Grant [PHY-9876773] FX We wish to acknowledge support from the U.S. Department of Energy Grant No. DE-FG02-92ER40747 and the National Science Foundation Grant No. PHY-9876773. NR 15 TC 2 Z9 2 U1 1 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD OCT PY 2000 VL 3 IS 10 AR 100101 PG 9 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V26ZO UT WOS:000208583700001 ER PT J AU Lin, XTE Whittum, DH AF Lin, Xintian E. Whittum, David H. TI Image current heating on a metal surface due to charged bunches SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article AB When charged particles pass through a metal pipe, they are accompanied by an image current on the metal surface. With intense short bunches passing near or even into the metal surface, the peak image current density can be very high. This current may result in substantial temperature rise on the surface, especially in high peak current, multibunch operation. In this paper, we derive an explicit formula for the surface temperature rise due to this previously unrecognized pulsed heating effect and show that this effect dominates the proposed linear coherent light source collimator spoiler and wire scanner heating. Without proper account, it can result in component and instrument failures. The result also applies to optical transition radiation screens, profile screens, wire scanners, exit windows, and targets, which the beam crosses. C1 [Lin, Xintian E.; Whittum, David H.] Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Lin, XTE (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. FU Department of Energy [DE-AC03-76SF00515] FX We would like to acknowledge Josef C. Frisch for suggesting this problem. This work was supported by the Department of Energy under Contract No. DE-AC03-76SF00515. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD OCT PY 2000 VL 3 IS 10 AR 101001 DI 10.1103/PhysRevSTAB.3.101001 PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V26ZO UT WOS:000208583700002 ER PT J AU Power, JG Conde, ME Gai, W Konecny, R Schoessow, P Kanareykin, AD AF Power, J. G. Conde, M. E. Gai, W. Konecny, R. Schoessow, P. Kanareykin, A. D. TI Measurements of the longitudinal wakefields in a multimode, dielectric wakefield accelerator driven by a train of electron bunches SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article ID WAKE-FIELD AB We report on the experimental demonstration of a novel wakefield acceleration technique where a short electron bunch excites a broadband harmonic frequency spectrum, in a cylindrical dielectric structure, to synthesize an accelerating waveform. The structure is designed to have its TM0n modes nearly equally spaced so that the modes generated by a single short electron bunch constructively interfere in the neighborhood of integral multiples of the fundamental wavelength producing large acceleration gradients. Realization of a harmonic multimode structure requires more stringent design considerations than a single-mode structure, since the permittivity and loss tangent of the material should not change substantially over the bandwidth of the structure. In this experiment, a bunch train of four 5 nC electron bunches, separated by 760 ps (one net wavelength), were passed through a 60 cm long dielectric-lined cylindrical harmonic structure. Use of a train of drive bunches spaced by one wavelength reinforced the accelerating wakefield; observation of the energy loss of each bunch via a magnetic spectrometer served as a diagnostic of the wakefield. The measured energy spectrum of the four beams after passing through the waveguide was found to be in excellent agreement with the predictions of the analytic model. This result demonstrates that a dielectric can be fabricated which can synthesize the required wakefield. We also discuss potential advantages of this harmonic approach over conventional single-mode wakefield accelerators. C1 [Power, J. G.; Conde, M. E.; Gai, W.; Konecny, R.; Schoessow, P.] Argonne Natl Lab, Argonne, IL 60439 USA. [Kanareykin, A. D.] St Petersburg Elect Engn Univ, St Petersburg 197376, Russia. RP Power, JG (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. FU U.S. Department of Energy, Division of High Energy Physics [W-31-109-ENG-38] FX We appreciate the interesting ideas put forth by Dr. T-B. Zhang, Professor J.L. Hirshfield, and Professor T.C. Marshall and the useful discussions with Professor J. Rosenzweig and Dr. J. Simpson. This work was supported by the U.S. Department of Energy, Division of High Energy Physics, under Contract No. W-31-109-ENG-38 NR 6 TC 38 Z9 38 U1 1 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD OCT PY 2000 VL 3 IS 10 AR 101302 DI 10.1103/PhysRevSTAB.3.101302 PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V26ZO UT WOS:000208583700004 ER PT J AU Rimmer, RA Byrd, JM Li, D AF Rimmer, R. A. Byrd, J. M. Li, D. TI Comparison of calculated, measured, and beam sampled impedances of a higher-order-mode-damped rf cavity SO PHYSICAL REVIEW SPECIAL TOPICS-ACCELERATORS AND BEAMS LA English DT Article AB Accelerating structures with damped higher-order modes (HOMs) have been the focus of many studies over the past decade. This report compares the results of numerical simulations of damping of HOMs using a new calculation technique applied to the case of the PEP-II rf cavity. We compare these results using this technique, which was not yet developed at the time of the original design, with bench and beam-based measurements of the HOM damping. These results show agreement with bench measurements of the shunt impedances of the strongest HOMs as well as measurements of the beam-induced signals on cavities installed in PEP-II. C1 [Rimmer, R. A.; Byrd, J. M.; Li, D.] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. [Byrd, J. M.] Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Rimmer, RA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. EM RARimmer@lbl.gov FU U.S. Department of Energy [DE-AC03-76SF00098] FX We would like to acknowledge useful discussions with Kwok Ko, Cho Ng, and the SLAC impedance modeling group. We would also like to thank the PEP-II operations crew for helping with the beam measurements. This work was supported by the U.S. Department of Energy under Contract No. DE-AC03-76SF00098. NR 16 TC 4 Z9 4 U1 2 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-4402 J9 PHYS REV SPEC TOP-AC JI Phys. Rev. Spec. Top.-Accel. Beams PD OCT PY 2000 VL 3 IS 10 AR 102001 PG 9 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA V26ZO UT WOS:000208583700005 ER PT J AU Oganessian, YT Utyonkov, VK Lobanov, YV Abdullin, FS Polyakov, AN Shirokovsky, IV Tsyganov, YS Gulbekian, GG Bogomolov, SL Gikal, BN Mezentsev, AN Iliev, S Subbotin, VG Sukhov, AM Ivanov, OV Buklanov, GV Subotic, K Itkis, MG Moody, KJ Wild, JF Stoyer, NJ Stoyer, MA Lougheed, RW AF Oganessian, YT Utyonkov, VK Lobanov, YV Abdullin, FS Polyakov, AN Shirokovsky, IV Tsyganov, YS Gulbekian, GG Bogomolov, SL Gikal, BN Mezentsev, AN Iliev, S Subbotin, VG Sukhov, AM Ivanov, OV Buklanov, GV Subotic, K Itkis, MG Moody, KJ Wild, JF Stoyer, NJ Stoyer, MA Lougheed, RW TI Synthesis of superheavy nuclei in Ca-48+Pu-244 interactions SO PHYSICS OF ATOMIC NUCLEI LA English DT Article ID ELEMENTS; STABILITY; ISOTOPES; FISSION; FUSION; CA-48; HEAVY; DECAY; N=162 AB This article reports the results of experiments aimed at producing hypothetical long-lived superheavy elements located near the spherical-shell closures with Z greater than or equal to 114 and N greater than or equal to 172. For the synthesis of superheavy nuclei, we used a combination of neutron-rich reaction partners, with a Pu-244 target and a Ca-48 projectile. The sensitivity of the present experiment exceeded by more than two orders of magnitude previous attempts at synthesizing superheavy nuclides in reactions of Ca-48 projectiles with actinide targets. We observed new decay sequences of genetically linked alpha decays terminated by spontaneous fission. The high measured alpha-particle energies, together with the long decay times and spontaneous fission terminating the chains, offer evidence for the decay of nuclei with high atomic numbers. The decay properties of the synthesized nuclei are consistent with the consecutive alpha decays originating from the parent nuclides (288,289)114, produced in the 3n- and 4n-evaporation channels with cross sections of about a picobarn. The present observations can be considered experimental evidence for the existence of the "island of stability" of superheavy elements and are discussed in terms of modern theoretical approaches. (C) 2000 MAIK "Nauka/Interperiodica ". C1 Dubna Joint Nucl Res Inst, Dubna 141980, Moscow Oblast, Russia. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Oganessian, YT (reprint author), Dubna Joint Nucl Res Inst, Dubna 141980, Moscow Oblast, Russia. NR 43 TC 37 Z9 37 U1 0 U2 0 PU MAIK NAUKA/INTERPERIODICA/SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013-1578 USA SN 1063-7788 EI 1562-692X J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD OCT PY 2000 VL 63 IS 10 BP 1679 EP 1687 DI 10.1134/1.1320137 PG 9 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 373ZM UT WOS:000165320000002 ER PT J AU Garcia, AL Wagner, W AF Garcia, AL Wagner, W TI Time step truncation error in direct simulation Monte Carlo SO PHYSICS OF FLUIDS LA English DT Article ID BOLTZMANN-EQUATION; APPROXIMATION METHODS; CONVERGENCE PROOF AB The time step truncation error in direct simulation Monte Carlo calculations is found to be O(Delta t(2)) for a variety of simple flows, both transient and steady state. The measured errors in the transport coefficients (viscosity, thermal conductivity, and self-diffusion) are in good agreement with predictions from Green-Kubo analysis [N. Hadjiconstantinou, Phys. Fluids 12, 2634 (2000)]. (C) 2000 American Institute of Physics. [S1070-6631(00)00110-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Sci & Engn, Berkeley, CA 94720 USA. Weierstrass Inst Appl Anal & Stochast, D-10117 Berlin, Germany. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP Garcia, AL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Computat Sci & Engn, Berkeley, CA 94720 USA. NR 14 TC 63 Z9 64 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD OCT PY 2000 VL 12 IS 10 BP 2621 EP 2633 DI 10.1063/1.1289691 PG 13 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 351RB UT WOS:000089171000022 ER PT J AU Davis, JP Sturtevant, B AF Davis, JP Sturtevant, B TI Separation length in high-enthalpy shock/boundary-layer interaction SO PHYSICS OF FLUIDS LA English DT Review ID LAMINAR BOUNDARY-LAYER; SHOCK-WAVE; COMPRESSION-CORNER; HYPERSONIC FLOW; ESTABLISHMENT; FLOWFIELDS; VEHICLES; TUNNEL AB Experiments were performed in the T5 Hypervelocity Shock Tunnel to investigate nonequilibrium real-gas effects on separation length using a double-wedge geometry and nitrogen test gas. Local external flow conditions were estimated by computing the inviscid nonequilibrium flow field. A new scaling parameter was developed to approximately account for wall temperature effects on separation length for a laminar nonreacting boundary layer and arbitrary viscosity law. A classification was introduced to divide mechanisms for real-gas effects into those acting internal and external to viscous regions of the flow. Internal mechanisms were further subdivided into those arising upstream and downstream of separation. Analysis based on the ideal dissociating gas model and a scaling law for separation length of a nonreacting boundary layer showed that external mechanisms due to dissociation may decrease separation length at low incidence but depend on the free-stream dissociation at high incidence. A limited numerical study of reacting boundary layers showed that internal mechanisms due to recombination occurring in the boundary layer upstream of separation cause a slight decrease in separation length relative to a nonreacting boundary layer with the same external conditions. Correlations were obtained of experimentally measured separation length using local external flow parameters computed for reacting flow, which scales out external mechanisms but not internal mechanisms. These showed the importance of the new scaling parameter in high-enthalpy flows, a linear relationship between separation length and reattachment pressure ratio, and a Reynolds-number effect for transitional interactions. A significant increase in scaled separation length was observed in the experimental data at high enthalpy. The increase was attributed to an internal mechanism arising from recombination in the free-shear layer downstream of separation, perhaps altering its velocity profile. This real-gas effect depends on the combined presence of free-stream dissociation and a cold wall. (C) 2000 American Institute of Physics. [S1070- 6631(00)51310-5]. C1 CALTECH, Grad Aeronaut Labs, Pasadena, CA 91125 USA. RP Davis, JP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 126 TC 18 Z9 18 U1 1 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD OCT PY 2000 VL 12 IS 10 BP 2661 EP 2687 AR PII [S1070-6631(00)51310-5] DI 10.1063/1.1289553 PG 27 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 351RB UT WOS:000089171000025 ER PT J AU Ganguli, G Merlino, R Davidson, RC AF Ganguli, G Merlino, R Davidson, RC TI Special topic: Dusty plasmas tutorial papers from the 41st Annual Meeting of the APS Division of Plasma Physics - Foreword SO PHYSICS OF PLASMAS LA English DT Editorial Material C1 USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Ganguli, G (reprint author), USN, Res Lab, Div Plasma Phys, Washington, DC 20375 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 3846 EP 3846 PG 1 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900003 ER PT J AU Uzdensky, DA Kulsrud, RM AF Uzdensky, DA Kulsrud, RM TI Two-dimensional numerical simulation of the resistive reconnection layer SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETIC RECONNECTION; PLASMA AB In this paper a two-dimensional, time dependent, numerical simulation of a reconnection current layer in incompressible resistive magnetohydrodynamics with uniform resistivity in the limit of very large Lundquist numbers is presented. Realistic boundary conditions derived consistently from the outside magnetic field are used, and the effect of the back pressure from flow into the separatrix region is also taken into account. It is found that within a few Alfven times the system evolves from an arbitrary initial state to a steady state consistent with the Sweet-Parker model, even if the initial state is Petschek-like. (C) 2000 American Institute of Physics. [S1070-664X(00)05110-7]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Uzdensky, DA (reprint author), Univ Chicago, Chicago, IL 60637 USA. NR 14 TC 66 Z9 67 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 4018 EP 4030 DI 10.1063/1.1308081 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900027 ER PT J AU Hurricane, OA Chandran, BDG Cowley, SC AF Hurricane, OA Chandran, BDG Cowley, SC TI Internal kink stability of large aspect ratio high-beta tokamaks SO PHYSICS OF PLASMAS LA English DT Article ID PLASMAS; PRESSURE AB Theoretically, high-beta (beta similar to 1) tokamaks offer a large fusion power efficiency advantage over low-beta devices. However, if high-beta tokamaks are inherently unstable then such devices will never be realized. In particular, kink modes are thought to be the most serious obstacle to high-beta operations. High-beta tokamaks are characterized by a very large Shafranov shift with a thin "boundary layer" on the outboard side of the device and a large "core" region of vertical flux surfaces comprising most of the central volume. In this paper, the energy principle is used to compute the magnetohydrodynamic internal kink stability of such devices in the large aspect ratio limit with a low toroidal mode number. A class of internal kink mode similar to the usual low-beta kink is present; the stability against these modes is computed. A set of parameters describing a kink stable high-beta equilibrium is given. Stability is shown to be dependent on the shape of the plasma boundary. (C) 2000 American Institute of Physics. [S1070-664X(00)00510-3]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RP Hurricane, OA (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 USA. NR 12 TC 4 Z9 4 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 4043 EP 4051 DI 10.1063/1.1288489 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900029 ER PT J AU Fredrickson, E Bell, M Budny, RV Synakowski, E AF Fredrickson, E Bell, M Budny, RV Synakowski, E TI Nonlinear evolution of double tearing modes in tokamaks SO PHYSICS OF PLASMAS LA English DT Article ID FUSION TEST REACTOR; REVERSED MAGNETIC SHEAR; BOOTSTRAP CURRENT; TFTR; ISLANDS; PLASMA; TRANSPORT; THRESHOLD AB The Delta' formalism with neoclassical modifications has proven to be a useful tool in the study of tearing modes in high beta, collisionless plasmas. In this paper the formalism developed for the inclusion of neoclassical effects on tearing modes in monotonic q-profile plasmas is extended to plasmas with hollow current profiles and double rational surfaces. First, the classical formalism of tearing modes in the Rutherford regime in low beta plasmas is extended to q profiles with two rational surfaces and it is shown that this formalism is readily extended to include neoclassical effects. The evolution of a double tearing mode on the Tokamak Fusion Test Reactor is then simulated. Reasonable agreement is found for the outer island, but the stabilizing effect of the neoclassical term is overly large for the inner island. (C) 2000 American Institute of Physics. [S1070-664X(00)03110-4]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Fredrickson, E (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 35 TC 23 Z9 23 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 4112 EP 4120 DI 10.1063/1.1289893 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900037 ER PT J AU Fredrickson, E Budny, RV Darrow, D Fu, GY Hosea, J Phillips, CK Wilson, JR Van Dam, JW AF Fredrickson, E Budny, RV Darrow, D Fu, GY Hosea, J Phillips, CK Wilson, JR Van Dam, JW TI Observation of modes at frequencies near the second Alfven gap in the Tokamak Fusion Test Reactor SO PHYSICS OF PLASMAS LA English DT Article ID EIGENMODE; TFTR AB Modes have been observed near the frequency of the second Alfven gap during off-axis H-minority heating experiments in the circular cross-section Tokamak Fusion Test Reactor. The observation of these modes is surprising in that the second gap, which is generally opened with ellipticity, is expected to be small, of order (r/R)(2). A model is proposed in which the second gap is opened by the fast ion beta, which is shown to be able to introduce mode coupling, much as toroidal effects introduce mode coupling for Toroidal Alfven Eigenmodes (TAE). With the low inferred energy of the fast ion tail (30-50 keV), the fast ion bounce resonance condition is assumed to drive the modes. The modes are seen with and without accompanying TAE mode activity. (C) 2000 American Institute of Physics. [S1070- 664X(00)03210-9]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. RP Fredrickson, E (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 10 TC 1 Z9 1 U1 2 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 4121 EP 4125 DI 10.1063/1.1289894 PG 5 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900038 ER PT J AU Sze, H Coleman, PL Failor, BH Fisher, A Levine, JS Song, Y Waisman, EM Apruzese, JP Chong, YK Davis, J Cochran, FL Thornhill, JW Velikovich, AL Weber, BV Deeney, C Coverdale, CA Schneider, R AF Sze, H Coleman, PL Failor, BH Fisher, A Levine, JS Song, Y Waisman, EM Apruzese, JP Chong, YK Davis, J Cochran, FL Thornhill, JW Velikovich, AL Weber, BV Deeney, C Coverdale, CA Schneider, R TI Initial results for an argon Z pinch using a double-shell gas puff SO PHYSICS OF PLASMAS LA English DT Article ID RAYLEIGH-TAYLOR INSTABILITY; SUPPRESSION; PLASMAS AB Recent observations are given for an argon double-shell gas puff imploded with up to 4 MA in 200 ns on the Double Eagle generator [G. B. Frazier , Digest of Technical Papers, Fourth IEEE Pulsed Power Conference (IEEE, Piscataway, NJ, 1983), p. 583]. Good K-shell x-ray output with good pinch quality was observed. A novel experimental procedure was used to selectively seed the inner or outer gas plenums with a chlorine tracer. The tracer data provide the first direct experimental evidence that the mass initially closest to the axis is the dominant contributor to the hot core of the radiating pinch. (C) 2000 American Institute of Physics. [S1070-664X(00)00710-2]. C1 Maxwell Phys Int, San Leandro, CA 94577 USA. USN, Res Lab, Washington, DC 20375 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. US DOE, Washington, DC 20585 USA. RP Sze, H (reprint author), Maxwell Phys Int, 2700 Merced St, San Leandro, CA 94577 USA. RI Velikovich, Alexander/B-1113-2009 NR 13 TC 41 Z9 45 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 4223 EP 4226 DI 10.1063/1.1288491 PG 4 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900046 ER PT J AU Karasik, M Zweben, SJ AF Karasik, M Zweben, SJ TI Experiments and modeling of an instability of an atmospheric pressure arc SO PHYSICS OF PLASMAS LA English DT Article ID HELICAL INSTABILITIES; STABILITY; FURNACE; CATHODE; JETS AB An instability of a free-burning atmospheric pressure approximate to 200 A carbon arc is investigated experimentally and modeled analytically. The presence of the instability is found to depend critically on cathode dimensions. In particular, for cylindrical cathodes, the instability occurs only for a narrow range of cathode diameters. Cathode spot motion is proposed as the mechanism of the instability. A simple fluid model combining the effect of the cathode spot motion and the inertia of the cathode jet successfully describes the shape of the arc column during low amplitude instability. The amplitude of cathode spot motion required by the model is in agreement with measurements. The average jet velocity required is approximately equal to that found from applied oscillating transverse magnetic field experiments. The primary reasons for cathode spot motion are most likely cathode vaporization and interaction of arc current with the current distribution in the cathode. Cathode surface temperature distribution is likely to be the reason for cathode geometry dependence. (C) 2000 American Institute of Physics. [S1070-664X(00)00310-4]. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Karasik, M (reprint author), USN, Res Lab, Code 6731,4555 Overlook Ave SW, Washington, DC 20375 USA. NR 45 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD OCT PY 2000 VL 7 IS 10 BP 4326 EP 4340 AR PII [S1070-664X(00)00310-4] DI 10.1063/1.1288401 PG 15 WC Physics, Fluids & Plasmas SC Physics GA 353QX UT WOS:000089287900058 ER PT J AU Balazs, NL Browne, JC Louck, JD Strottman, DS AF Balazs, NL Browne, JC Louck, JD Strottman, DS TI Nicholas Constantine Metropolis - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 SUNY Stony Brook, Stony Brook, NY 11794 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Balazs, NL (reprint author), SUNY Stony Brook, Stony Brook, NY 11794 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 0031-9228 J9 PHYS TODAY JI Phys. Today PD OCT PY 2000 VL 53 IS 10 BP 100 EP 101 DI 10.1063/1.1325208 PG 2 WC Physics, Multidisciplinary SC Physics GA 358FA UT WOS:000089546100023 ER PT J AU Crease, RP AF Crease, RP TI The art and artistry of textbooks SO PHYSICS WORLD LA English DT Editorial Material C1 SUNY Stony Brook, Dept Philosophy, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Crease, RP (reprint author), SUNY Stony Brook, Dept Philosophy, Stony Brook, NY 11794 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8585 J9 PHYS WORLD JI Phys. World PD OCT PY 2000 VL 13 IS 10 BP 18 EP 18 PG 1 WC Physics, Multidisciplinary SC Physics GA 361XN UT WOS:000089749700019 ER PT J AU French, NB Priebe, S Haas, W AF French, NB Priebe, S Haas, W TI Implementing mercury CEMs on hazardous waste incinerators SO POLLUTION ENGINEERING LA English DT Article C1 Sky Ltd, Napa, CA USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID USA. Iowa State Univ, Ames Lab, Ames, IA USA. RP French, NB (reprint author), Sky Ltd, Napa, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CAHNERS-DENVER PUBLISHING CO PI OAK BROOK PA 2000 CLEARWATER DR, OAK BROOK, IL 60523-8809 USA SN 0032-3640 J9 POLLUT ENG JI Pollut. Eng. PD OCT PY 2000 VL 32 IS 10 BP 38 EP 41 PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 362LK UT WOS:000089779300019 ER PT J AU Ford, JV Sumpter, BG Noid, DW Barnes, MD AF Ford, JV Sumpter, BG Noid, DW Barnes, MD TI Material homogeneity and structural dynamics in polymer-electrolyte composite microparticles SO POLYMER LA English DT Article DE polymer composite; polymer electrolyte; poly(ethylene glycol) ID POLY(ETHYLENE OXIDE); BLEND MICROPARTICLES; GAS-PHASE; SCATTERING; POLYETHERS; MOLECULES; COMPLEX; NEUTRON AB We describe optical diffraction, or 2D angle-resolved light scattering, measurements for probing structure and morphological dynamics of isolated poly(ethylene glycol) (PEG) microparticles doped with NaCl or CaCl2. Of specific interest was the effect of dopant salt concentration and polymer host molecular weight on composite microparticle homogeneity (phase-separation behavior) and evaporation dynamics determined from changes in both microparticle size and refractive index with time. In general the drying rate was higher for microparticles doped with CaCl2, and only in the case of CaCl2 doped microparticles was PEG molecular weight found to effect the drying rate. Furthermore, CaCl2 doped microparticles had a higher concentration threshold with regard to homogeneity when compared with NaCl doped microparticles. The results are discussed in terms of the known structures for monovalent electrolytes doped into PEG thin films and polymer-like oligomers in the gas phase, and on possible modifications of these structures due to differences in the intermolecular interactions of the two cationic species with the residual solvent and the polymer matrix. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Barnes, MD (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, MS 6142,POB 2008,Bldg 4500S, Oak Ridge, TN 37831 USA. RI Sumpter, Bobby/C-9459-2013 OI Sumpter, Bobby/0000-0001-6341-0355 NR 25 TC 4 Z9 4 U1 0 U2 5 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD OCT PY 2000 VL 41 IS 22 BP 8075 EP 8082 DI 10.1016/S0032-3861(00)00161-0 PG 8 WC Polymer Science SC Polymer Science GA 336PT UT WOS:000088312500020 ER PT J AU Ramirez-Vargas, E Navarro-Rodriguez, D Medellin-Rodriguez, FJ Huerta-Martinez, BM Lin, JS AF Ramirez-Vargas, E Navarro-Rodriguez, D Medellin-Rodriguez, FJ Huerta-Martinez, BM Lin, JS TI Morphological and mechanical properties of polypropylene [PP]/poly(ethylene vinyl acetate) [EVA] blends. I. Homopolymer PP/EVA systems SO POLYMER ENGINEERING AND SCIENCE LA English DT Article ID SMALL-ANGLE SCATTERING; LAMELLAR 2-PHASE SYSTEMS; X-RAY-SCATTERING; MELTING BEHAVIOR; ETHYLENE; COPOLYMER; CRYSTALLIZATION; POLYETHYLENE AB Morphological and mechanical properties of polypropylene [PP]/poly(ethylene vinyl acetate) [EVA] blends have been studied. Infrared results using thin films first indicated a transition toward compatibility between both components at concentrations above 40% EVA. The transition was verified with different experimental techniques and it was associated to morphological changes and mechanical properties. The PP/EVA blends were mechanically evaluated in terms of impact and tensile strength to determine the influence of blending on the performance properties of these materials. Agreement was found between the transition and the enhancement of both elongation at break and impact strength. C1 UAC, Fac Quim, Programa Interinst Posgrado, Saltillo 25270, Coahuila, Mexico. Ctr Invest Quim Aplicada, Saltillo 25100, Coahuila, Mexico. UASLP, FCQ, CIEP, San Luis Potosi 78210, Mexico. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Ramirez-Vargas, E (reprint author), UAC, Fac Quim, Programa Interinst Posgrado, Blvd V Carranza & Jose Cardenas Valdes, Saltillo 25270, Coahuila, Mexico. NR 35 TC 22 Z9 22 U1 1 U2 5 PU SOC PLASTICS ENG INC PI BROOKFIELD PA 14 FAIRFIELD DR, BROOKFIELD, CT 06804-0403 USA SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD OCT PY 2000 VL 40 IS 10 BP 2241 EP 2250 DI 10.1002/pen.11356 PG 10 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 367QD UT WOS:000090072200013 ER PT J AU Adams, DP Vasile, MJ Krishnan, ASM AF Adams, DP Vasile, MJ Krishnan, ASM TI Microgrooving and microthreading tools for fabricating curvilinear features SO PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY LA English DT Article DE microtools; micromachining; ultraprecision ID FOCUSED ION-BEAM; 3-DIMENSIONAL MICROSTRUCTURES; MICROFABRICATION; LITHOGRAPHY; TECHNOLOGY; MICROCOILS; LATHE AB This paper presents techniques for fabricating microscopic, curvilinear features in a variety of workpiece materials. Microgrooving and microthreading tools with cutting widths as small as 13 mum are made by focused ion beam sputtering and used for ultraprecision machining. Tool fabrication involves directing a 20 keV gallium beam at polished cylindrical punches made of cobalt M42 high-speed steel or C2 tungsten carbide to create a number of critically aligned facets. Sputtering produces rake facets of desired angle and cutting edges having radii of curvature equal to 0.4 mum. Clearance for minimizing frictional drag of a tool results from a particular ion beam/target geometry that accounts for the sputter yield dependence on incidence angle. It is believed that geometrically specific cutting tools of this dimension have not been made previously. Numerically controlled, ultraprecision machining with microgrooving tools results in a close match between tool width and feature size. Microtools are used to machine 13-mum wide, 4-mum deep, helical grooves in polymethyl methacrylate and 6061 AI cylindrical workpieces. Microgrooving tools are also used to fabricate sinusoidal cross-sectional features in planar metal samples. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Louisiana Tech Univ, Ruston, LA 71270 USA. RP Adams, DP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 32 TC 39 Z9 42 U1 0 U2 8 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Int. Soc. Precis. Eng. Nanotechnol. PD OCT PY 2000 VL 24 IS 4 BP 347 EP 356 DI 10.1016/S0141-6359(00)00045-3 PG 10 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA 365QV UT WOS:000089962700008 ER PT J AU Gardner, CD Tribble, DL Young, DR Ahn, D Fortmann, SP AF Gardner, CD Tribble, DL Young, DR Ahn, D Fortmann, SP TI Population frequency distributions of HDL, HDL2, and HDL3 cholesterol and apolipoproteins A-I and B in healthy men and women and associations with age, gender, hormonal status, and sex hormone use: The Stanford Five City Project SO PREVENTIVE MEDICINE LA English DT Article DE apolipoproteins; diet; epidemiology; exercise; hormones; lifestyle; lipids; lipoproteins; men; risk factors; smoking; women ID DENSITY-LIPOPROTEIN CHOLESTEROL; CORONARY-ARTERY DISEASE; ISCHEMIC-HEART-DISEASE; RISK-FACTORS; PRECIPITATION PROCEDURE; MYOCARDIAL-INFARCTION; PLASMA-LIPOPROTEINS; 5-CITY PROJECT; SUBFRACTIONS; METABOLISM AB Background. The purpose of this study is to present population-based frequency distribution data for several lipoprotein-related variables and to examine their associations with gender, age, menopausal status, and sex hormone use. Methods. High-density lipoprotein cholesterol (HDLC), HDL2-C, HDL3-C, apolipoprotein (Apo) A-I, and Apo B were measured in a population-based sample of 1,027 healthy adults from four California cities who participated in the 1989-1990 survey of the Stanford Five City Project. These data were examined cross-sectionally with sociodemographic and other related variables. Results. Relative to men, all of the HDL-related parameters-HDL-C, HDL2-C, HDL3-C, Apo A-I-were significantly higher and Apo B levels were significantly lower among women (P < 0.001). Menopausal status was not associated with HDL-related parameters, but Apo B levels were higher in post- versus premenopausal women (P < 0.001), Among women, HDL-C and Apo A-I levels were higher in oral contraceptive and estrogen replacement therapy users (P = 0.003). Most of the significant findings remained statistically significant after adjusting for age, body mass index, smoking, energy expenditure, and alcohol intake. Conclusions. These population-based data indicate that gender, menopausal status, and the use of sex hormones among women are associated with differential levels of one or more of HDL-C, HDL2-C, HDL3-C, Apo A-I, and Apo B, independent of age and a broad set of lifestyle factors. (C) 2000 American Health Foundation and Academic Press. C1 Stanford Univ, Sch Med, Stanford Ctr Res Dis Prevent, Palo Alto, CA 94304 USA. Stanford Univ, Sch Med, Dept Med, Palo Alto, CA 94304 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Johns Hopkins Sch Med, Johns Hopkins Ctr Hlth Promot, Baltimore, MD 21205 USA. RP Fortmann, SP (reprint author), Stanford Univ, Sch Med, Stanford Ctr Res Dis Prevent, 1000 Welch Rd, Palo Alto, CA 94304 USA. FU NHLBI NIH HHS [5 T32 HL07034, HL54606-01A1, HL21906] NR 42 TC 15 Z9 17 U1 1 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0091-7435 J9 PREV MED JI Prev. Med. PD OCT PY 2000 VL 31 IS 4 BP 335 EP 345 DI 10.1006/pmed.2000.0715 PG 11 WC Public, Environmental & Occupational Health; Medicine, General & Internal SC Public, Environmental & Occupational Health; General & Internal Medicine GA 358PK UT WOS:000089566300007 PM 11006058 ER PT J AU Gardner, CD Tribble, DL Young, DR Ahn, D Fortmann, SP AF Gardner, CD Tribble, DL Young, DR Ahn, D Fortmann, SP TI Associations of HDL, HDL2, and HD3 cholesterol and apolipoproteins A-I and B with lifestyle factors in healthy women and men: The Stanford Five City Project SO PREVENTIVE MEDICINE LA English DT Article DE apolipoproteins; diet; epidemiology; exercise; hormones; lifestyle; lipids; lipoproteins; men; risk factors; smoking; women ID DENSITY-LIPOPROTEIN-CHOLESTEROL; CORONARY-ARTERY DISEASE; ISCHEMIC-HEART-DISEASE; 5-CITY PROJECT; MYOCARDIAL-INFARCTION; SUBFRACTIONS HDL2-C; ALCOHOL-CONSUMPTION; OVERWEIGHT MEN; PLASMA-LIPIDS; SERUM-LIPIDS AB Background. Measures of the two major high-density lipoprotein (HDL) subfractions, HDL2 and HDL3, and the major apolipoproteins of HDL and low-density lipoprotein (LDL), Apo A-I and Apo B, may be etiologically important factors in the development of coronary artery disease. The association of lifestyle factors with these lipoprotein-related variables remains unclear. Methods. HDL-C, HDL2-C, HDL3-C, Apo A-I, and Apo B levels were determined in a population-based sample of 1,027 healthy women and men aged 25-64 years, from four California cities who participated in the 1989/1990 survey of the Stanford Five City Project. In this cross-sectional study we examined the independent associations of these lipoprotein-related variables with body mass index (BMI), cigarette smoking, daily energy expenditure, alcohol intake, dietary intake, and hormone use (oral contraceptives and estrogen replacement therapy). Results. In general, BMI and alcohol intake were the strongest independent predictors of the lipoprotein-related variables. The negative association of BMI with HDL-C was attributable primarily to the association with the HDL2-C subfraction, while for alcohol intake the positive association with HDL-C was attributable primarily to the association with HDL3-C, particularly in men. Among men, but not women, energy expenditure was a significant independent predictor of each of the lipoprotein-related variables, with positive associations observed for HDL-C, HDL2-C, HDL3-C, and Apo A-I and a negative association observed for Apo B (P < 0.005). Conclusions. Data from this population-based sample suggest that specific lifestyle factors are more strongly associated with some lipoprotein-related variables than with others, with notable gender differences. (C) 2000 American Health Foundation and Academic Press. C1 Stanford Univ, Sch Med, Stanford Ctr Res Dis Prevent, Palo Alto, CA 94304 USA. Stanford Univ, Sch Med, Dept Med, Palo Alto, CA 94304 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Johns Hopkins Univ, Sch Med, Johns Hopkins Ctr Hlth Promot, Baltimore, MD 21205 USA. RP Fortmann, SP (reprint author), Stanford Univ, Sch Med, Stanford Ctr Res Dis Prevent, 1000 Welch Rd, Palo Alto, CA 94304 USA. FU NHLBI NIH HHS [5 T32 HL07034, HL54606-01A1, HL21906] NR 40 TC 16 Z9 16 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0091-7435 J9 PREV MED JI Prev. Med. PD OCT PY 2000 VL 31 IS 4 BP 346 EP 356 DI 10.1006/pmed.2000.0716 PG 11 WC Public, Environmental & Occupational Health; Medicine, General & Internal SC Public, Environmental & Occupational Health; General & Internal Medicine GA 358PK UT WOS:000089566300008 PM 11006059 ER PT J AU Tama, F Gadea, FX Marques, O Sanejouand, YH AF Tama, F Gadea, FX Marques, O Sanejouand, YH TI Building-block approach for determining low-frequency normal modes of macromolecules SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE collective motion; RTB method; rigid bodies; rotation-translation; B-factors; conformational change ID PANCREATIC TRYPSIN-INHIBITOR; CONFORMATIONAL CHANGE; DOMAIN MOTIONS; MOLECULAR-DYNAMICS; SINGLE-PARAMETER; PROTEIN DYNAMICS; CITRATE SYNTHASE; LYSOZYME; DEOXYMYOGLOBIN; FLUCTUATIONS AB Normal mode analysis of proteins of various sizes, ranging from 46 (crambin) up to 858 residues (dimeric citrate synthase) were performed, by using standard approaches, as well as a recently proposed method that rests on the hypothesis that low-frequency normal modes of proteins can be described as pure rigid-body motions of blocks of consecutive amino-acid residues. Such a hypothesis is strongly supported by our results, because we show that the latter method, named RTB, yields very accurate approximations for the low-frequency normal modes of all proteins considered. Moreover, the quality of the normal modes thus obtained depends very little on the way the polypeptidic chain is split into blocks, Noteworthy, with six aminoacids per block, the normal modes are almost as accurate as with a single amino-acid per block. In this case, for a protein of n residues and N atoms, the RTB method requires the diagonalization of an n x n matrix, whereas standard procedures require the diagonalization of a 3N x 3N matrix. Being a fast method, our approach can be useful for normal mode analyses of large systems, paving the way for further developments and applications in contexts for which the normal modes are needed frequently, as for example during molecular dynamics calculations. Proteins 2000;41:1-7. (C) 2000 Wiley-Liss, Inc. C1 Univ Toulouse 3, IRSAMC, CNRS, Phys Quant Lab, Toulouse, France. Lawrence Berkeley Natl Lab, Natl Energy Res Sci Comp Ctr, Berkeley, CA USA. RP Sanejouand, YH (reprint author), Ctr Rech Paul Pascal, CNRS, UPR 8641, Ave Albert Schweitzer, F-33600 Pessac, France. RI Tama, Florence/A-7077-2016 OI Tama, Florence/0000-0003-2021-5618 NR 36 TC 328 Z9 338 U1 0 U2 18 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD OCT 1 PY 2000 VL 41 IS 1 BP 1 EP 7 PG 7 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 349VR UT WOS:000089066700001 PM 10944387 ER PT J AU Prausnitz, JM AF Prausnitz, JM TI Thermodynamics of structured fluids. Hard science for soft materials SO PURE AND APPLIED CHEMISTRY LA English DT Article; Proceedings Paper CT 16th IUPAC Conference on Chemical Thermodynamics (ICCT-2000) CY AUG 06-11, 2000 CL HALIFAX, CANADA SP Int Union Pure & Appl Chem ID DIFFERENT SEQUENCE STATISTICS; LINEAR RANDOM COPOLYMERS; POLYMERIC MIXTURES; BLENDS AB At liquid-like densities, molecules of complex fluids can assume a variety of structures (or positions) in space; when the molecules contain many atoms as, for example, in polymers, that variety becomes very large. Further, when confined to a narrow space, it is possible to achieve structures that are not normally observed. Thanks to recent advances in statistical mechanics and molecular physics, and thanks to increasingly fast computers, it is now possible to calculate a fluid's structure, that is, the positions of molecules at equilibrium under given conditions. Calculation of fluid structure is useful because thermodynamic properties depend strongly on that structure, leading to possible applications for new materials. Three examples illustrate some recent developments; each example is presented only schematically (with a minimum of equations) to indicate the physical basis of the mathematical description. The first example considers the effect of branching on self-assembly (micellization) of copolymers (with possible long-range applications in medicine). The second and third examples consider the effect of confinement on fluid structure: first, crystallization in a narrow, confined space to produce a desired crystal structure (with possible applications for light-emitting diodes) and second, suppression of micellization of a diblock copolymer in a thin film (with possible application in lithography). Whenever possible, theoretical calculations are compared with experimental results. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Prausnitz, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU INT UNION PURE APPLIED CHEMISTRY PI RES TRIANGLE PK PA 104 TW ALEXANDER DR, PO BOX 13757, RES TRIANGLE PK, NC 27709-3757 USA SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD OCT PY 2000 VL 72 IS 10 BP 1819 EP 1834 DI 10.1351/pac200072101819 PG 16 WC Chemistry, Multidisciplinary SC Chemistry GA 408NN UT WOS:000167332400004 ER PT J AU Lymar, SV Schwarz, HA Czapski, G AF Lymar, SV Schwarz, HA Czapski, G TI Medium effects on reactions of the carbonate radical with thiocyanate, iodide, and ferrocyanide ions SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article DE carbonate radical; pK(a); thiocyanate radical; reduction potential; pulse radiolysis ID FLASH-PHOTOLYSIS; DEPENDENCE AB Results are presented which show that there is no pH dependence of the carbonate radical reactivity toward SCN-, I-, and Fe(CN)(6)(4-) above pH 8.5. It is demonstrated that observations in the literature on these reactions which have been interpreted to show a pK(a) of 9.5 for the carbonate radical, in disagreement with other reports that the radical is not protonated in/this pH region, can Ire explained by the medium effects. It is also shown that previous studies of the reaction between carbonate radical and thiocyanate are in error, and the mechanism of this reaction is elucidated. Published by Elsevier Science Ltd. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. RP Lymar, SV (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 14 TC 31 Z9 31 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT PY 2000 VL 59 IS 4 BP 387 EP 392 DI 10.1016/S0969-806X(00)00277-2 PG 6 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 359QJ UT WOS:000089623300007 ER PT J AU Costes, S Streuli, CH Barcellos-Hoff, MH AF Costes, S Streuli, CH Barcellos-Hoff, MH TI Quantitative image analysis of laminin immunoreactivity in skin basement membrane irradiated with 1 GeV/nucleon iron particles SO RADIATION RESEARCH LA English DT Article ID PLASMINOGEN-ACTIVATOR; EXTRACELLULAR-MATRIX; IONIZING-RADIATION; MAMMARY-GLAND; MELANOMA-CELLS; INDUCTION; EXPRESSION; CHAIN; MOUSE; COLLAGENASE AB We previously reported that laminin immunoreactivity in mouse mammary epithelium is altered shortly after whole-body irradiation with 0.8 Gy from 600 MeV/nucleon iron ions but is unaffected after exposure to sparsely ionizing radiation. This observation led us to propose that the effect could be due to protein damage from the high ionization density of the ion tracks. If so, we predicted that it would be evident soon after radiation exposure in basement membranes of other tissues and would depend on ion fluence. To test this hypothesis, we used immunofluorescence, confocal laser scanning microscopy, and image segmentation techniques to quantify changes in the basement membrane of mouse skin epidermis. At 1 h after exposure to 1 GeV/nucleon iron ions with doses from 0.03 to 1.6 Gy, neither the visual appearance nor the mean pixel intensity of laminin in the basement membrane of mouse dorsal skin epidermis was altered compared to sham-irradiated tissue. This result does not support the hypothesis that particle traversal directly affects laminin protein integrity. However, the mean pixel intensity of laminin immunoreactivity was significantly decreased in epidermal basement membrane at 48 and 96 h after exposure to 0.8 Gy 1 GeV/nucleon iron ions. We confirmed this effect with two additional antibodies raised against affinity-purified laminin 1 and the E3 fragment of the long-arm of laminin 1. In contrast, collagen type IV, another component of the basement membrane, was unaffected. Our studies demonstrate quantitatively that densely ionizing radiation elicits changes in skin microenvironments distinct from those induced by sparsely ionizing radiation. Such effects may might contribute to the carcinogenic potential of densely ionizing radiation by altering cellular signaling cascades mediated by cell-extracellular matrix interactions. (C) 2000 by Radiation Research Society. C1 Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Dept Nucl Engn, Berkeley, CA 94720 USA. Univ Manchester, Sch Biol Sci, Manchester, Lancs, England. RP Barcellos-Hoff, MH (reprint author), Univ Calif Berkeley, EO Lawrence Berkeley Natl Lab, Div Life Sci, Bldg 74-174,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Costes, Sylvain/D-2522-2013 OI Costes, Sylvain/0000-0002-8542-2389 NR 39 TC 13 Z9 14 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 2000 VL 154 IS 4 BP 389 EP 397 DI 10.1667/0033-7587(2000)154[0389:QIAOLI]2.0.CO;2 PG 9 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 359QU UT WOS:000089624200005 PM 11023602 ER PT J AU Anderson, CW Allalunis-Turner, MJ AF Anderson, CW Allalunis-Turner, MJ TI Human T053 from the malignant glioma-derived cell lines M059J and M059K has a cancer-associated mutation in exon 8 SO RADIATION RESEARCH LA English DT Article ID DEPENDENT PROTEIN-KINASE; DNA-DAMAGE; CATALYTIC SUBUNIT; CYCLE ARREST; P53 PROTEIN; RADIATION; APOPTOSIS; STABILITY; MOUSE AB The protein coding segment of the TP53 genes from the glioma-derived cell lines M059J and M059K was sequenced. The sequences from both cell lines were identical over 5039 bp, including the gene segment containing exons 2 through 9, exon 10, and the proximal segment of exon 11. In both cells, the first nucleotide of codon 286 (GAA, Glu) is changed to an A (AAA, Lys). Comparison with the same TP53 segment from the A549 human lung carcinoma cell line revealed several differences in intron sequence. (C) 2000 by Radiation Research Society. C1 Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Univ Alberta, Dept Oncol, Edmonton, AB T6G 1Z2, Canada. Cross Canc Inst, Edmonton, AB T6G 1Z2, Canada. RP Anderson, CW (reprint author), Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. FU NIGMS NIH HHS [GM52825] NR 27 TC 27 Z9 29 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD OCT PY 2000 VL 154 IS 4 BP 473 EP 476 DI 10.1667/0033-7587(2000)154[0473:HTFTMG]2.0.CO;2 PG 4 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 359QU UT WOS:000089624200016 PM 11023613 ER PT J AU Privette, JL Asner, GP Conel, J Huemmrich, KF Olson, R Rango, A Rahman, AF Thome, K Walter-Shea, EA AF Privette, JL Asner, GP Conel, J Huemmrich, KF Olson, R Rango, A Rahman, AF Thome, K Walter-Shea, EA TI The EOS prototype validation exercise (PROVE) at Jornada: Overview and lessons learned SO REMOTE SENSING OF ENVIRONMENT LA English DT Article AB Tho forth Observing System (EOS) instrument teams must validate the operational products they produce from the Terra spacecraft data. As a pilot for future validation activities, four EOS teams (MODIS, MISR, ASTER, and Landsat-7) and community experts conducted an Il-dar field campaign in May 1997 near Las Cruces, NM. The goals of the Prototype Validation Exercise (PROVE) included (1) gaining experience in the collection and use of field data for EOS product validation; (2) developing coordination, measurement, and data-archiving protocols; and (3) compiling a synoptic land and atmospheric data set for testing algorithms. PROVE was held at the USDA-Agricultural Research Service's (ARS) Jornada Experimental Range, an expansive desert plateau hosting a complex mosaic of grasses and shrubs. Most macroscopic variables affecting the radiation environment were measured with ground air-borne (including AVIRIS and laser altimeter), and space-borne sensors (including AVHRR, Landsat TM SPOT, POLDER, and GOES). The Oak Ridge Distributed Active Archive Center (DAAC) then used campaign data sets to prototype Mercury, its Internet-based data harvesting and distribution system. This article provides general information about PROVE and assesses the progress made toward the campaign goat. Primary successes included the rapid campaign formulation and execution, measurement protocol development, and the significant collection, reduction, and sharing of data among participants. However, the PROVE data were used primarily for arid-la nd research and model validation rather than for validating satellite products, and the data were slow; to reach the DAAC and hence public domain. The lessons learned included: (1) validation campaigns can be rapidly organized and implemented if there are focused objectives and on-site facilities and expertise; (2) data needs, organization, storage, and access issues must be addressed at the onset of campaign planning; and (3) the end-to-end data collection, release, and publication environment may need to be readdressed by program managers, funding agencies, and journal editors if rapid and comprehensive validation of operational satellite products is to occur Published by Elsevier Science Inc. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Maryland, Dept Geog, Baltimore, MD 21201 USA. Oak Ridge Natl Lab, Oak Ridge, TN USA. USDA ARS, Beltsville Agr Res Ctr, Beltsville, MD 20705 USA. Calif State Univ Los Angeles, Dept Geog, Los Angeles, CA 90032 USA. Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. Univ Nebraska, Dept Nat Resource Sci, Lincoln, NE 68583 USA. RP Privette, JL (reprint author), NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. RI Privette, Jeffrey/G-7807-2011; Thome, Kurtis/D-7251-2012; Asner, Gregory/G-9268-2013 OI Privette, Jeffrey/0000-0001-8267-9894; Asner, Gregory/0000-0001-7893-6421 NR 25 TC 29 Z9 31 U1 2 U2 9 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD OCT PY 2000 VL 74 IS 1 BP 1 EP 12 DI 10.1016/S0034-4257(00)00117-6 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 356NA UT WOS:000089448300001 ER PT J AU Qin, WH Gerstl, SAW AF Qin, WH Gerstl, SAW TI 3-D scene modeling of semidesert vegetation cover and its radiation regime SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID RADIOSITY METHOD; REFLECTANCE AB To explore the potential of multiangle remote sensing for estimating biophysical or ecological parameters over a variety of landscapes, a modeling tool that is capable of handling three-dimensional (3-D) heterogeneous structures, deriving ecological parameters from the vegetation structure, and effectively working on different scene scales is very desirable. A 3-D scene modeling approach for these purposes is presented in this paper. This 3-D model fulfills its goal by taking advantage of radiosity theory and computer graphics techniques. It consists of two major modules: a modified extended L-systems (MELS) method to gene-rate a 3-D realistic scene and a radiosity-graphics combined method (RGM) to calculate the radiation regime based on the 3-D structures rendered with MELS. The 3-D simulation tool is then evaluated using field measurements of both plant structure and spectra collected during the NASA Earth Observing Satellite Prototype Validation Exercise Jornada field campaign near Las Cruces, NM. The modeled scene reflectance is compared with measurements from three platforms (ground tower, and satellite) at various scales (from the size of individual shrub component to satellite pixels of kilometers). The agreement with measured reflectances is excellent at all sampling scales tested. As an example of the model's application, we use the model output to examine the validity of a linear mixture scheme over the Jornada semidesert scene. The result shows that the larger the sampling size (at least larger than the size of the shrub component), the better the hypothesis is satisfied because of the unique structure of the Jornada scene: dense plant clumps (shrub component) sparsely scattered on a predominantly bare soil background. A range of possible applications of this 3-D scene model is highlighted. and further work needed for 3-D modeling is also discussed. (C) Elsevier Science Inc., 2000. C1 NASA, Goddard Space Flight Ctr, Raytheon, ITSS, Greenbelt, MD 20771 USA. Univ Calif Los Alamos Natl Lab, NIS, RS, Los Alamos, NM USA. RP Qin, WH (reprint author), NASA, Goddard Space Flight Ctr, Raytheon, ITSS, Code 916, Greenbelt, MD 20771 USA. NR 20 TC 73 Z9 96 U1 2 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD OCT PY 2000 VL 74 IS 1 BP 145 EP 162 DI 10.1016/S0034-4257(00)00129-2 PG 18 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 356NA UT WOS:000089448300011 ER PT J AU Bitteker, LJ Wood, BP Davis, HA Waganaar, WJ Boyd, ID Lovberg, RH AF Bitteker, LJ Wood, BP Davis, HA Waganaar, WJ Boyd, ID Lovberg, RH TI Development of the Los Alamos continuous high average-power microsecond pulser ion accelerator SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID BEAM AB The continuous high average-power microsecond pulser (CHAMP) ion accelerator is being constructed at Los Alamos National Laboratory. Progress on the testing of the CHAMP diode is discussed. A direct simulation Monte Carlo computer code is used to investigate the puffed gas fill of the CHAMP anode. High plenum pressures and low plenum volumes are found to be desirable for effective gas puffs. The typical gas fill time is 150-180 mu s from initiation of valve operation to end of fill. Results of anode plasma production at three stages of development are discussed. Plasma properties are monitored with electric and magnetic field probes. From this data, the near coil plasma density under nominal conditions is found to be on the order of 1 x 10(16) cm(-3). Large error is associated with this calculation due to inconsistencies between tests and the limitations of the instrumentation used. The diode insulating magnetic field is observed to result in lower density plasma with a more diffuse structure than for the cases when the insulating field is not applied. The importance of these differences in plasma quality on the beam production is yet to be determined. (C) 2000 American Institute of Physics. [S0034-6748(00)06010-X]. C1 Univ Calif Los Alamos Natl Lab, Plasma Phys Grp, Los Alamos, NM 87545 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Bitteker, LJ (reprint author), Univ Calif Los Alamos Natl Lab, Plasma Phys Grp, POB 1663, Los Alamos, NM 87545 USA. NR 9 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD OCT PY 2000 VL 71 IS 10 BP 3677 EP 3683 DI 10.1063/1.1310353 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 358JG UT WOS:000089554500012 ER PT J AU Woenckhaus, J Kohling, R Winter, R Thiyagarajan, P Finet, S AF Woenckhaus, J Kohling, R Winter, R Thiyagarajan, P Finet, S TI High pressure-jump apparatus for kinetic studies of protein folding reactions using the small-angle synchrotron x-ray scattering technique SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID DIFFRACTION; CELL; MESOPHASES; CRYSTALS AB An apparatus suitable for pressure-jump experiments with variable pressure amplitude and a fast response time to facilitate time-resolved small-angle x-ray scattering at synchrotron facilities is described. The high pressure-jump apparatus is capable of performing bidirectional pressure jumps at a time resolution as high as 5 ms. The high pressure sample cell presented has flat diamond windows and is suited for pressures up to 0.7 GPa operating in the temperature range from -40 to 120 degrees C. The cell is designed for investigating biological and other soft condensed matter materials. Modifications on the window supports allow also simultaneous wide-angle x-ray scattering data to be taken. We have used the equipment to study the kinetics of protein folding reactions. The performance of the apparatus is demonstrated by presenting data on the pressure-induced un/refolding reaction of the water-soluble protein SNase WT. (C) 2000 American Institute of Physics. [S0034- 6748(00)04410-5]. C1 Univ Dortmund, Dept Chem, D-44227 Dortmund, Germany. Argonne Natl Lab, IPNS, Argonne, IL 60439 USA. European Synchrotron Radiat Facil, F-38043 Grenoble, France. RP Woenckhaus, J (reprint author), Univ Dortmund, Dept Chem, Otto Hahn Str 6, D-44227 Dortmund, Germany. OI Winter, Roland/0000-0002-3512-6928 NR 18 TC 51 Z9 53 U1 1 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD OCT PY 2000 VL 71 IS 10 BP 3895 EP 3899 DI 10.1063/1.1290508 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 358JG UT WOS:000089554500047 ER PT J AU Sturesson, U Heikoop, JM Risk, MJ AF Sturesson, U Heikoop, JM Risk, MJ TI Modern and Palaeozoic iron ooids - a similar volcanic origin SO SEDIMENTARY GEOLOGY LA English DT Article DE iron ooids; volcanism; Ordovician; Indonesia; Baltoscandia; Wales; Czech Republic ID ORDOVICIAN AB The discovery of an unconsolidated deposit of iron ooids of a kind not previously described, and in the vicinity of a volcanic island in Indonesia has shed new light on the genesis of many ancient iron oolites. The discovery shows that iron ooid formation is geologically a rapid process. The ooids form by chemical precipitation of cryptocrystalline iron oxyhydroxides on available grains on the seafloor, from seawater enriched with Fe, Al and Si. The enrichment can be a result of hydrothermal fluids, volcanic ash falls into shallow basins or rapid weathering of fresh volcanic rocks. Ordovician iron ooids from northern Europe are strikingly similar to the modem ooids in chemical composition, REE distributions and internal structures. The differences in mineralogy can be explained as diagenetic transformation reactions under different environments. A model for the formation of the Ordovician iron ooids in northern Europe from volcaniclastic material is presented, which could be applicable to other ancient oolites in the world. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Uppsala Univ, Dept Eart Sci Hist Geol & Palaeontol, S-75236 Uppsala, Sweden. LANL, EES 1, Los Alamos, NM 87545 USA. McMaster Univ, Sch Geog & Geol, Hamilton, ON L8S 4M1, Canada. RP Sturesson, U (reprint author), Uppsala Univ, Dept Eart Sci Hist Geol & Palaeontol, Norbyvagen 22, S-75236 Uppsala, Sweden. RI Heikoop, Jeffrey/C-1163-2011 NR 28 TC 33 Z9 36 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0037-0738 J9 SEDIMENT GEOL JI Sediment. Geol. PD OCT PY 2000 VL 136 IS 1-2 BP 137 EP 146 DI 10.1016/S0037-0738(00)00091-9 PG 10 WC Geology SC Geology GA 359XT UT WOS:000089637900009 ER PT J AU Schmid, AK Bartelt, NC Hwang, RQ AF Schmid, AK Bartelt, NC Hwang, RQ TI Bronze formation and the motion of mesoscopic tin clusters on a copper surface SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT US-Japan Seminar on Mesoscopic Phenomena on Surfaces CY APR 02-08, 2000 CL PARK CITY, UTAH AB To study the dynamics of alloy phase transformations, we deposited submonolayer amounts of Sn onto Cu(111) surfaces. The subsequently observed formation of bronze alloy was found to be surprisingly complex. First, the Sn forms 2D clusters with a 2 x 2 structure and typical diameters of the order of 100 nm. Then the Sn clusters move across the Cu surface and shrink in size, leaving dilute bronze in their wake. The curious motion of the Sn clusters can be interpreted as an example of chemomechanical energy transduction on a surprisingly small length scale. Thus the Sn clusters are microscopic engines and one can discuss their fundamental mechanical properties. A speculative comparison of the self-propelled motion of the Sn clusters with other isothermal engines, such as molecular biological machines, is considered. C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Schmid, AK (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 8 TC 3 Z9 3 U1 1 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD OCT-DEC PY 2000 VL 7 IS 5-6 BP 515 EP 519 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 400WA UT WOS:000166893600002 ER PT J AU Kellogg, GL Plass, RA AF Kellogg, GL Plass, RA TI Mesoscopic scale observations of surface alloying, surface phase transitions, domain coarsening, and 3D island growth: Pb on Cu(100) SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT US-Japan Seminar on Mesoscopic Phenomena on Surfaces CY APR 02-08, 2000 CL PARK CITY, UT ID COPPER 100; LEAD; SCATTERING; LEED; OVERLAYERS AB Low energy electron microscopy (LEEM) is used to investigate the dynamics of Pb overlayer growth on Cu(100). By following changes in surface morphology during Pb deposition, we measure the amount of Cu transported to the surface as the Pb first alloys into the surface during formation of the c(4 x 4) phase and subsequently dealloys during conversion to the c(2 x 2) phase. We find that the added coverage of Cu during alloying is consistent with the proposed model for the c(4 x 4) alloy phase, but the added coverage during dealloying is not consistent with the accepted model for the c(2 x 2) phase. To account for the discrepancy, we propose that Cu atoms are incorporated in the c(2 x 2) structure. Island growth and step advancement during the transition from the c(2 x 2) to c(5 root2 x root2)R 45 degrees structure agrees with this model. We also use LEEM to identify the order and temperature of the two-dimensional melting phase transitions for the three Pb/Cu(100) surface structures. Phase transitions for the c(5 root2 x root2)R45 degrees and c(4 x 4) structures are first-order, but the c(2 x 2) transition is second-order. We determine that rotational domains of the c(5 root2 x root2)R45 degrees structure coarsen from nanometer- to micron-sized dimensions with relatively mild heating (similar to 120 degreesC), whereas coarsening of c(4 x 4) domain requires considerably higher temperatures (similar to 400 degreesC). In studies of three-dimensional island formation, we find that the islands grow asymmetrically with an orientational dependence that is directly correlated with the domain structure of the underlying c(5 root2 x root2)R45 degrees phase. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kellogg, GL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 12 TC 9 Z9 9 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD OCT-DEC PY 2000 VL 7 IS 5-6 BP 649 EP 655 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 400WA UT WOS:000166893600024 ER PT J AU Jennison, DR Bogicevic, A AF Jennison, DR Bogicevic, A TI Ultrathin aluminum oxide films: Al-sublattice structure and the effect of substrate on ad-metal adhesion SO SURFACE SCIENCE LA English DT Article DE aluminium oxide; amorphous surfaces; chemisorption; copper; density functional calculations; insulating films; metal-insulator interfaces; palladium; platinum; surface structure, morphology, roughness, and topography ID AB-INITIO; MOLECULAR-DYNAMICS; SURFACE; AL2O3; PSEUDOPOTENTIALS; KAPPA-AL2O3; ADSORPTION; NI3AL(111); MICROSCOPY; NIAL(110) AB First principles density-functional slab calculations are used to study 5 Angstrom (two O-layer) Al2O3 films on Ru(0001) and Al(111). Using larger unit cells than in a recent study, it is found that the lowest energy stable film has an even mix of tetrahedral (t) and octahedral to) site Al ions, and thus most closely resembles the Ic-phase of bulk alumina. Here, alternating zig-zag rows of t and o occur within the surface plane, resulting ina greater average lateral separation of the Al-ions than with pure t or o. A second structure with an even mix of t and o has also been found, consisting of alternating stripes. These patterns mix easily, can exist in three equivalent directions on basal substrates, and can also be displaced laterally, suggesting a mechanism for a loss of long-range order in the Al-sublattice. While the latter would cause the film to appear amorphous in diffraction experiments, local coordination and film density are little affected. On a film supported by rigid Ru(0001), overlayers of Cu, Pd, and Pt bind similarly as on bulk truncated alpha -Al2O3(0001). However, when the film is supported by soft Al(111), the adhesion of Cu, Pd, and Pt metal overlayers is significantly increased: oxide-surface Al atoms rise so only they contact the overlayer, while substrate Al metal atoms migrate into the oxide film. Thus the binding energy of metal overlayers is strongly substrate dependent, and our numbers for the above Pd-overlayer systems bracket a recent experimentally derived value for a film on NiAl(IIO). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Surface & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Sandia Natl Labs, Surface & Interface Sci Dept, POB 5800, Albuquerque, NM 87185 USA. EM drjenni@sandia.gov NR 36 TC 52 Z9 53 U1 2 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 EI 1879-2758 J9 SURF SCI JI Surf. Sci. PD OCT 1 PY 2000 VL 464 IS 2-3 BP 108 EP 116 DI 10.1016/S0039-6028(00)00578-1 PG 9 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 368BP UT WOS:000090098000013 ER PT J AU Walters, CF McCarty, KF Soares, EA Van Hove, MA AF Walters, CF McCarty, KF Soares, EA Van Hove, MA TI The surface structure of alpha-Al2O3 determined by low-energy electron diffraction: aluminum termination and evidence for anomolously large thermal vibrations SO SURFACE SCIENCE LA English DT Letter DE aluminium oxide; low energy electron diffraction (LEED); low index single crystal surfaces; surface relaxation and reconstruction ID LEED CRYSTALLOGRAPHY; SUBSTRATE; ENERGETICS AB We have determined the surface structure of alpha -Al2O3(0001) using dynamical low-energy electron diffraction (LEED). Sapphire surfaces were prepared in three different ways, and the diffraction results were analyzed using an exhaustive search of possible models. For all sample processing conditions, the clearly favored structure has a single aluminum layer termination and a large first interlayer contraction. In addition, we find that the surface atoms have unusually large vibrational amplitudes at room temperature, suggestive of an anharmonic vibrational mode. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Livermore, CA 94551 USA. Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP McCarty, KF (reprint author), Sandia Natl Labs, Livermore, CA 94551 USA. EM mccarty@sandia.gov RI Van Hove, Michel/A-9862-2008; McCarty, Kevin/F-9368-2012; Soares, Edmar/C-2303-2013 OI Van Hove, Michel/0000-0002-8898-6921; McCarty, Kevin/0000-0002-8601-079X; NR 28 TC 64 Z9 65 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD OCT 1 PY 2000 VL 464 IS 2-3 BP L732 EP L738 DI 10.1016/S0039-6028(00)00687-7 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 368BP UT WOS:000090098000003 ER PT J AU Smith, SJ Wigley, TML Nakicenovic, N Raper, SCB AF Smith, SJ Wigley, TML Nakicenovic, N Raper, SCB TI Climate implications of greenhouse gas emissions scenarios SO TECHNOLOGICAL FORECASTING AND SOCIAL CHANGE LA English DT Article AB Global-mean temperature and sea-level implications are calculated for four preliminary emissions scenarios presented elsewhere in this issue. Total anthropogenic temperature change in the year 2100 ranges from 1.3-4.0 degreesC using the four scenarios for upper and lower bounds on emissions and high and low values for the climate sensitivity. The lower bound is higher than that given in the IPCC Second Assessment Report, due mainly to lower future sulfur dioxide emissions. These lower emissions also have the effect of reducing uncertainties associated with sulfate aerosol forcing. Significant future climate changes occur in all scenarios, indicating that adaptation policies need to be considered as an important component of climate-change policy. (C) 2000 Elsevier Science Inc. C1 Pacific NW Natl Lab, Washington, DC 20024 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria. Univ E Anglia, Norwich NR4 7TJ, Norfolk, England. RP Smith, SJ (reprint author), Pacific NW Natl Lab, 901 D St SW,Suite 900, Washington, DC 20024 USA. NR 12 TC 7 Z9 7 U1 2 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0040-1625 J9 TECHNOL FORECAST SOC JI Technol. Forecast. Soc. Chang. PD OCT PY 2000 VL 65 IS 2 BP 195 EP 204 DI 10.1016/S0040-1625(99)00099-2 PG 10 WC Business; Planning & Development SC Business & Economics; Public Administration GA 373KF UT WOS:000165287700004 ER PT J AU Gonera, M Peryt, TM Durakiewicz, T AF Gonera, M Peryt, TM Durakiewicz, T TI Biostratigraphical and palaeoenvironmental implications of isotopic studies (O-18, C-13) of middle Miocene (Badenian) foraminifers in the Central Paratethys SO TERRA NOVA LA English DT Article ID PLANKTONIC-FORAMINIFERA AB The cause of the middle Miocene Badenian salinity crisis in the Central Paratethys is addressed by examining the palaeotemperature evolution of Badenian waters before and after the deposition of evaporites. Selected foraminifer taxa (Globigerinoides spp., Globigerina bulloides, and Uvigerina) characterizing, respectively, the near-surface, intermediate, and bottom layers of the water column, were studied in two boreholes of SW Poland. The delta O-18 and delta C-13 values for these taxa show distinct differences which can be explained by the temperature difference between surface and bottom waters during deposition. These values also show temporal changes corresponding to the water temperature evolution in the Badenian basin. Different and quickly changing environmental conditions have been inferred from changes in foraminifer assemblages. They explain why biostratigraphic subdivisions based on well-recognized assemblages are the most accurate approach for determining the biostratigraphy of middle Miocene deposits in the Central Paratethys. The results of isotopic studies indicate that evaporites occur in a part of the Badenian section that was characterized by the lowest temperatures in the studied sections. C1 Panstwowy Inst Geol, PL-00975 Warsaw, Poland. PAN, Inst Ochrony Przyrody, PL-31120 Krakow, Poland. Marie Curie Sklodowska Univ, Inst Phys, PL-20031 Lublin, Poland. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Peryt, TM (reprint author), Panstwowy Inst Geol, Rakowiecka 4, PL-00975 Warsaw, Poland. OI Durakiewicz, Tomasz/0000-0002-1980-1874 NR 42 TC 34 Z9 34 U1 0 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0954-4879 J9 TERRA NOVA JI Terr. Nova PD OCT PY 2000 VL 12 IS 5 BP 231 EP 238 DI 10.1046/j.1365-3121.2000.00303.x PG 8 WC Geosciences, Multidisciplinary SC Geology GA 462BM UT WOS:000170400200006 ER PT J AU Borglin, SE Moridis, GJ Oldenburg, CM AF Borglin, SE Moridis, GJ Oldenburg, CM TI Experimental studies of the flow of ferrofluid in porous media SO TRANSPORT IN POROUS MEDIA LA English DT Article DE ferrofluid; magnetic fluids; Hele-shaw cell; environmental remediation ID FLUIDS AB This paper presents laboratory-scale experimental results of the behavior of ferrofluids in porous media consisting of sands and sediments. Ferrofluids are colloidal suspensions of magnetic particles stabilized in various carrier liquids. In the presence of an external magnetic field, a ferrofluid becomes magnetized as the particles align with the magnetic field. We investigate the potential for controlling fluid emplacement in porous media using magnetic fields. These experiments show that in laboratory-scale porous media experiments (up to 0.25 m), with both vertical gravitational forces and lateral magnetic forces acting simultaneously, the magnetic field produces strong attractive forces on the ferrofluid, particularly in the vicinity of the magnet. These holding forces result in a predictable configuration of the fluid in the porous medium which is dependent on the magnetic field and independent of flow pathway or heterogeneity of the porous medium. No significant retention effects due to flow through variably saturated sands are observed. While the proposed field engineering applications of ferrofluids are promising, the observations to date are particularly relevant at the laboratory scale where the decrease in magnetic field strength with distance from a magnet is less of a limitation than in larger scale applications. Ferrofluids may find immediate application in any situation where it is desirable to control the motion or final configuration of fluid in an experimental flow apparatus without direct physical contact. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Borglin, SE (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RI Oldenburg, Curtis/L-6219-2013; Borglin, Sharon/I-1013-2016 OI Oldenburg, Curtis/0000-0002-0132-6016; NR 19 TC 53 Z9 53 U1 0 U2 10 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0169-3913 J9 TRANSPORT POROUS MED JI Transp. Porous Media PD OCT PY 2000 VL 41 IS 1 BP 61 EP 80 DI 10.1023/A:1006676931721 PG 20 WC Engineering, Chemical SC Engineering GA 335CV UT WOS:000088225200004 ER PT J AU Bruce, BD AF Bruce, BD TI Chloroplast transit peptides: structure, function and evolution SO TRENDS IN CELL BIOLOGY LA English DT Review ID PLANT ARABIDOPSIS-THALIANA; PROTEIN IMPORT MACHINERY; PRECURSOR PROTEINS; IN-VIVO; CHLAMYDOMONAS-REINHARDTII; GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE; RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE; TRANSLOCATION APPARATUS; ENDOSYMBIOTIC ORIGIN; ENVELOPE MEMBRANES AB It is thought that two to three thousand different proteins are targeted to the chloroplast, and the 'transit peptides' that act as chloroplast targeting sequences are probably the largest class of targeting sequences in plants. At a primary structural level, transit peptide sequences are highly divergent in length, composition and organization. An emerging concept suggests that transit peptides contain multiple domains that provide either distinct or overlapping functions. These functions include direct interaction wit envelope lipids, chloroplast receptors and the stromal processing peptidase. The genomic organization of transit peptides suggests that these domains might have originated from distinct exons, which were shuffled and streamlined throughout evolution to yield a modern, multifunctional transit peptide. Although still poorly characterized, this evolutionary process could yield transit peptides with different domain organizations. The plasticity of transit peptide design is consistent with the diverse biological functions of chloroplast proteins. C1 Univ Tennessee, Dept Biochem, Knoxville, TN 37996 USA. Univ Tennessee, Cellular & Mol Biol Dept, Knoxville, TN 37996 USA. Univ Tennessee, Ctr Legume Res, Knoxville, TN 37996 USA. Univ Tennessee, Grad Program Genome Sci, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Bruce, BD (reprint author), Univ Tennessee, Dept Biochem, Knoxville, TN 37996 USA. NR 67 TC 171 Z9 179 U1 1 U2 24 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0962-8924 J9 TRENDS CELL BIOL JI Trends Cell Biol. PD OCT PY 2000 VL 10 IS 10 BP 440 EP 447 DI 10.1016/S0962-8924(00)01833-X PG 8 WC Cell Biology SC Cell Biology GA 359AD UT WOS:000089588600007 PM 10998602 ER PT J AU Ersoy, DA McNallan, MJ Gogotsi, Y Erdemir, A AF Ersoy, DA McNallan, MJ Gogotsi, Y Erdemir, A TI Tribological properties of carbon coatings produced by high temperature chlorination of silicon carbide SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT ASME/STLE Tribology Conference CY OCT 01-04, 2000 CL SEATTLE, WA SP Soc Tribologists & Lubricat Engineers, ASME DE carbon; tribology; wear; chlorination; coatings; solid lubricants; raman spectroscopy ID DIAMOND; FILMS AB The tribological properties of highly disordered graphitic carbon layers formed on silicon carbide (SiC) substrates by reaction with chlorine and chlorine-hydrogen gas mixtures at 1000 degrees C were studied. Si was selectively removed from the near surface of SiC by chlorine gas, leaving behind a layer of carbon having high structural density and strong bonding characteristics. Tribological tests showed that the carbon films were highly adherent and able to reduce friction coefficients of the base SiC by factors of up to seven. There was little or no change in the frictional behavior of carbon layers when sliding velocity and load were increased. Low friction coefficients (similar to 0.1) could be obtained under wet, dry,polished, and rough conditions. The initially rough carbon surface underwent plastic flow producing a smooth, self-adjusting carbon layer. Structural morphology and the amount of disorder in the carbon layers were correlated with the friction and wear performance of the resultant films. C1 Univ Illinois, Civil & Mat Engn Dept, Chicago, IL 60607 USA. Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Univ Illinois, Civil & Mat Engn Dept, Chicago, IL 60607 USA. RI Gogotsi, Yury/B-2167-2008 OI Gogotsi, Yury/0000-0001-9423-4032 NR 13 TC 25 Z9 26 U1 0 U2 6 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 1040-2004 EI 1547-397X J9 TRIBOL T JI Tribol. Trans. PD OCT PY 2000 VL 43 IS 4 BP 809 EP 815 DI 10.1080/10402000008982412 PG 7 WC Engineering, Mechanical SC Engineering GA 357AA UT WOS:000089475300033 ER PT J AU Ballif, C Moutinho, HR Hasoon, FS Dhere, RG Al-Jassim, MM AF Ballif, C Moutinho, HR Hasoon, FS Dhere, RG Al-Jassim, MM TI Cross-sectional atomic force microscopy imaging of polycrystalline thin films SO ULTRAMICROSCOPY LA English DT Article DE cross-section; atomic force microscopy; polycrystalline film; scanning electron microscopy ID SCANNING-TUNNELING-MICROSCOPY; ELECTRON-MICROSCOPY; INGAASP/INGAP SUPERLATTICES; CAPACITANCE MICROSCOPY; COATINGS; HETEROSTRUCTURES; DEVICES; CELLS AB Atomic force microscopy (AFM) can be used to image cross-sections of thin-film samples. So far, however, it has mainly been used to study cross-sections of epitaxial systems or integrated circuits on crystalline substrates. In this paper, we show that AFM is a powerful tool to image fractured cross-sections of polycrystalline thin films deposited on crystalline and non-crystalline substrates, yielding unique information on the three-dimensional properties of the cross-sections, with a spatial resolution in the nm range. Original images of three different heterostructure systems are presented: Si(wafer)/SnO2/CdS/CdTe, glass/Mo/Cu(In,Ga)Se-2/CdS/ZnO, and glass/SnO2/WO3. We discuss the results by comparing AFM and scanning electron microscopy (SEM) images, and explain, for the different materials, why the AFM provides useful additional information. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Moutinho, HR (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Ballif, Christophe/G-4621-2012 NR 32 TC 10 Z9 10 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD OCT PY 2000 VL 85 IS 2 BP 61 EP 71 DI 10.1016/S0304-3991(00)00043-7 PG 11 WC Microscopy SC Microscopy GA 359AG UT WOS:000089588900001 ER PT J AU Adams, SM Greeley, MS AF Adams, SM Greeley, MS TI Ecotoxicological indicators of water quality: Using multi-response indicators to assess the health of aquatic ecosystems SO WATER AIR AND SOIL POLLUTION LA English DT Article DE bioindicators; ecosystem health; multiple stressors; water quality ID ECOLOGICAL RISK ASSESSMENT; BIOMARKERS; POPULATIONS; COMMUNITY AB As sensitive and ecologically relevant measures of environmental conditions, bioindicators can be used to assess the health of aquatic ecosystems which may be compromised by a variety of environmental stressors such as contaminants, sediments, nutrients, and varying temperature, salinity, and hydrologic regimes. The bioindicators approach is a proven bioassessment method that uses responses of key (sentinel) aquatic organisms both as integrators of stress effects and as sensitive response (early-warning) indicators of environmental health. This integrated approach involves measuring a suite of selected biological and ecological responses at several levels of biological organization from the biomolecular and biochemical to the community levels. When properly designed and applied in field situations, bioindicator studies can help identify causal mechanisms between environmental stressors and population and community-level effects, and serve as a basis for which the effectiveness of remedial actions on the health of aquatic organisms can be evaluated. Rapidly-responding sensitive biomarkers, such as biomolecular and biochemical responses, and slower-response ecologically relevant bioindicators, such as population and community responses, can be included in field bioassessment programs to provide measurement endpoints for use in environmental compliance, regulatory decision-making, and ecological risk assessments. This bioindicators approach should be particularly relevant in helping to identify and diagnose sources of stressors in environments impacted by multiple stressors. To demonstrate use of bioindicators in addressing water quality issues, spatial and temporal patters in various biological responses are related to spatial and temporal patterns of contaminants in two aquatic systems compromised by different stressors. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Adams, SM (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Greeley, Mark/D-2330-2016 OI Greeley, Mark/0000-0002-6088-5942 NR 31 TC 56 Z9 65 U1 4 U2 26 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD OCT PY 2000 VL 123 IS 1-4 BP 103 EP 115 DI 10.1023/A:1005217622959 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 364FH UT WOS:000089881000011 ER PT J AU Daniels, JI Bogen, KT Hall, LC AF Daniels, JI Bogen, KT Hall, LC TI Analysis of uncertainty and variability in exposure to characterize risk: Case study involving trichloroethylene groundwater contamination at Beale Air Force Base in California SO WATER AIR AND SOIL POLLUTION LA English DT Article DE exposure; ground water; joint uncertainty and variability; probability; risk; trichloroethylene ID WATER; TIME AB Quantitative assessments of potential human-health consequences from contaminants in environmental media routinely involve conservative deterministic, screening-level calculations of exposure and risk. Because these calculations generally are based on multiple upper-bound point estimates of input parameters, particularly for exposure attributes, they can yield results for decision makers that actually overstate the need for costly remediation. Alternatively, quantifying uncertainty and variability in exposure can provide a more informative and quantitative characterization of health risk. To illustrate, uncertainty and variability in exposure were analyzed for a hypothetical population at a specific site in California where there is trichloroethylene (TCE) contaminated ground water and a potential for its residential use. When uncertainty and variability in exposure were addressed jointly, the 95th-percentile upper-bound value of individual excess lifetime cancer risk was a factor approaching 10 lower than the most conservative deterministic estimate. Also, the probability of more than zero additional cases of cancer can be estimated, and in this case study it is less than 0.5 for a prospective residential population of up to 26,900 individuals present for any 7.6-y interval of a 70-y time period. Clearly, this probabilistic approach can provide reasonable and equitable risk-acceptability criteria for contaminated sites. C1 Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessment Div, Earth & Environm Sci Directorate, Livermore, CA 94551 USA. RP Daniels, JI (reprint author), Univ Calif Lawrence Livermore Natl Lab, Hlth & Ecol Assessment Div, Earth & Environm Sci Directorate, POB 808, Livermore, CA 94551 USA. NR 37 TC 9 Z9 10 U1 1 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD OCT PY 2000 VL 123 IS 1-4 BP 273 EP 298 DI 10.1023/A:1005231732471 PG 26 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 364FH UT WOS:000089881000024 ER PT J AU Simmons, CS Meyer, PD AF Simmons, CS Meyer, PD TI A simplified model for the transient water budget of a shallow unsaturated zone SO WATER RESOURCES RESEARCH LA English DT Article ID CONCENTRATION BOUNDARY-CONDITIONS; UNIFORM INITIAL CONDITIONS; RICHARDS EQUATION; SERIES SOLUTION; RAINFALL INTENSITY; SOIL; INFILTRATION; SIMULATION; PROFILE AB A simplified model describing the transient water budget of a shallow unsaturated soil profile is presented and applied to an example of long-term climatic conditions for a site near Coshocton, Ohio. Its conceptualization is simplified because the instantaneous redistribution of infiltrated water in a uniform soil profile is imposed. The model's formulation is a revision of that originally presented by Kim et al. [1996]. Runoff from a soil profile with uniform hydraulic properties is described by using an infiltration equation derived by Salvucci [1996] for ponded conditions. During storm periods the infiltration rate equals the rainfall intensity, unless that rate exceeds the saturated hydraulic conductivity, and then the input rate is determined by the infiltration equation for ponded conditions, with the excess applied water being accounted for as runoff. During interstorm periods, when the soil profile is drying due to evapotranspiration (ET) and drainage, the ET rate equals the potential evapotranspiration rate E-p, until the soil profile relative saturation s drops below a certain falling value of saturation S-f. When s < S-f then the ET rate is linearly proportional to s as given by (s/S-f) E-p. Drainage flux from a profile equals the hydraulic conductivity under a unit hydraulic gradient. Drainage for a 50-year-long record of climate on a daily basis for the Coshocton site compared well with measurements from four lysimeters. It is shown that the effective saturated hydraulic conductivity for the profile is determined by the runoff amount over the simulation period, and the value of S-f can be set so that the predicted drainage approximates that measured by lysimeters. This determines the appropriate cumulative ET for the site consistent with the climate data. The appropriate value of S-f also depends on the presumed profile depth, which is the plant root depth over which ET is extracted. C1 Pacific NW Natl Lab, Environm Technol Div, Richland, WA 99352 USA. RP Simmons, CS (reprint author), Pacific NW Natl Lab, Environm Technol Div, Batelle Blvd,POB 999, Richland, WA 99352 USA. OI Meyer, Philip/0000-0002-8714-4693 NR 27 TC 19 Z9 19 U1 3 U2 9 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 OCT PY 2000 VL 36 IS 10 BP 2835 EP 2844 DI 10.1029/2000WR900202 PG 10 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 359AP UT WOS:000089589600003 ER PT J AU Mozharivskyj, Y Lang, O Franzen, HF AF Mozharivskyj, Y Lang, O Franzen, HF TI Modulated crystal structure and electronic properties of semiconductor Cu47Si91P144 SO ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE LA English DT Article DE silicon copper phosphide; modulated superstructure; semiconductor; Anderson localization; band structure ID SUBSTITUTION; HF5CO1+XP3-X; PHOSPHORUS; NISI2P3 AB Crystals of the copper silicon phosphide were synthesized by the iodine gas transport technique. The x-ray single crystal methods revealed a big superstructure with the lattice parameters a = b = 44.510 and c = 20.772 Angstrom and a basic tetragonal substructure with a = 3.7092 and c = 5.1930 Angstrom. Analysis of the intensities showed that the superstructure has a 1/2, 1/2,1/2 tetragonal substructure with a = 22.255 and c = 10.386 Angstrom. This 1/2, 1/2, 1/2 substructure (Cu47Si91P144) and the basic tetragonal structure (Cu0.71Si1.29P2) were solved by the direct methods and refined in the I (4) over bar m2 space group. The phosphide is a semiconductor with a small energy gap of 0.0269(1) eV. The electrical properties are considered in terms of Anderson localization. The density of states was calculated using the extended Huckel tight binding method. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ Mainz, Inst Anorgan Chem & Analyt Chem, D-6500 Mainz, Germany. RP Franzen, HF (reprint author), Iowa State Univ, Ames Lab, Spedding Hall 342, Ames, IA 50011 USA. NR 28 TC 1 Z9 1 U1 0 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0044-2313 J9 Z ANORG ALLG CHEM JI Z. Anorg. Allg. Chem. PD OCT PY 2000 VL 626 IS 10 BP 2153 EP 2160 DI 10.1002/1521-3749(200010)626:10<2153::AID-ZAAC2153>3.0.CO;2-X PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 363BC UT WOS:000089813000020 ER PT J AU Evslin, J Halpern, MB Wang, JE AF Evslin, J Halpern, MB Wang, JE TI Cyclic coset orbifolds SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article ID CONFORMAL FIELD-THEORIES; AFFINE-G; ALGEBRAS; PERMUTATIONS; CHARACTERS; MODELS AB We apply the new orbifold duality transformations to discuss the special case of cyclic coset orbifolds in further detail. We focus in particular on the case of the interacting cyclic coset orbifolds, whose untwisted sectors are Z(lambda)(permutation)-invariant g/h coset constructions which are not lambda copies of coset constructions. Because lambda copies are not involved, the action of Z(lambda)(permutation) in the interacting cyclic coset orbifolds can be quite intricate. The stress tensors and ground state conformal weights of all the sectors of a large class of these orbifolds are given explicitly and special emphasis is placed on the twisted h subalgebras which are generated by the twisted (0, 0) operators of these orbifolds. We also discuss the systematics of twisted (0,0) operators in general coset orbifolds. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, ERnest Orlando Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Evslin, J (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM hllywd2@physics.berkeley.edu NR 30 TC 19 Z9 19 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD SEP 30 PY 2000 VL 15 IS 24 BP 3829 EP 3860 PG 32 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 361VZ UT WOS:000089746100005 ER PT J AU Chin, K Yu, XB Beleslin-Cokic, B Liu, C Shen, K Mohrenweiser, HW Noguchi, CT AF Chin, K Yu, XB Beleslin-Cokic, B Liu, C Shen, K Mohrenweiser, HW Noguchi, CT TI Production and processing of erythropoietin receptor transcripts in brain SO MOLECULAR BRAIN RESEARCH LA English DT Article DE erythropoietin receptor; brain transcript; alternative splicing; upstream transcription; anemic stress; induced expression ID CENTRAL-NERVOUS-SYSTEM; ENDOTHELIAL-CELLS; GENE-EXPRESSION; NITRIC-OXIDE; IN-VITRO; RAT HIPPOCAMPAL; MICE LACKING; MOUSE-BRAIN; FACTOR AP-2; NEURONS AB The expression of erythropoietin receptor (EpoR) in brain and neuronal cells, and hypoxia-responsive production of erythropoietin (Epo) in the brain suggests that the function of Epo as a survival or viability factor may extend beyond hematopoietic tissue and erythroid progenitor cells. Epo, produced by astrocytes and neurons, can be induced by hypoxia by severalfold, and in animal models Epo administration is neuroprotective to ischemic challenge. We characterized the human EpoR transcript in brain and neuronal cells to determine its contribution in regulating the Epo response in brain. Screening of a human brain cDNA library and quantitative analysis of EpoR transcripts indicate that the EpoR gene locus is transcriptionally active in brain. In addition to the proximal promoter that is active in hematopoietic cells, a significant proportion of transcripts originates far upstream from the EpoR coding region. Unlike erythroid cells with efficient splicing of EpoR transcripts to its mature form, brain EpoR transcripts are inefficiently or alternately processed with a bias towards the 3' coding region. In human EpoR transgenic mice, anemic stress induces expression of the transgene and endogenous EpoR gene in hematopoietic tissue and brain. In culture of neuronal cells, hypoxia induces EpoR expression and increases sensitivity to Epo. Induction of EpoR expression appears to be a consequence of increased transcription from the upstream region and proximal promoter, and a shift towards increased processing efficiency. These data suggest that in contrast to erythropoiesis where erythroid progenitor cells express high levels of EpoR and are directly responsive to Epo stimulation, the neuroprotective effect of Epo and its receptor may require two molecular events: the induction of Epo production by hypoxia and an increase in EpoR expression in neuronal cells resulting in increased sensitivity to Epo. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NIDDK, Biol Chem Lab, NIH, Bethesda, MD 20892 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Noguchi, CT (reprint author), NIDDK, Biol Chem Lab, NIH, Bethesda, MD 20892 USA. NR 54 TC 61 Z9 65 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-328X J9 MOL BRAIN RES JI Mol. Brain Res. PD SEP 30 PY 2000 VL 81 IS 1-2 BP 29 EP 42 DI 10.1016/S0169-328X(00)00157-1 PG 14 WC Neurosciences SC Neurosciences & Neurology GA 363LW UT WOS:000089838000004 PM 11000476 ER PT J AU Beck, ME Swartzlander-Guest, A Matson, R Keane, J Noufi, R AF Beck, ME Swartzlander-Guest, A Matson, R Keane, J Noufi, R TI CuIn(Ga)Se-2-based devices via a novel absorber formation process SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article DE compound semiconductor; chalcopyrite; CuIn(Ga)Se-2; solar cells ID CUINSE2 THIN-FILMS; HETEROJUNCTION SOLAR-CELLS; STRUCTURAL-PROPERTIES; CU(IN,GA)SE-2; SELENIZATION; GROWTH; TRANSPORT; SELENIDE; LAYERS; NA AB A novel pathway for the formation of copper-indium (gallium) diselenide has been developed. This two-stage process consists of(a) the formation of Cu-In-(Ga)-Se precursors, and (b) subsequent thermal treatment to form CuIn(Ga)Se-2. The morphology, structure and growth mechanism for several different precursor structures prepared under various conditions were studied and correlated to the deposition parameters as well as the structure and morphology of the annealed films. Photovoltaic devices prepared from CuInSe2 and CuIn0.75Ga0.25Se2 resulted in efficiencies of 10% and 13%, respectively. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, PV&EM Ctr, Golden, CO 80401 USA. Hahn Meitner Inst Berlin GmbH, D-14109 Berlin, Germany. RP Natl Renewable Energy Lab, PV&EM Ctr, 1617 Cole Blvd, Golden, CO 80401 USA. EM markus_beck@nrel.gov NR 41 TC 25 Z9 27 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 EI 1879-3398 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD SEP 30 PY 2000 VL 64 IS 2 BP 135 EP 165 DI 10.1016/S0927-0248(00)00066-0 PG 31 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 352LK UT WOS:000089217200003 ER PT J AU Kudoh, S Uechi, T Takayanagi, M Nakata, M Frei, H AF Kudoh, S Uechi, T Takayanagi, M Nakata, M Frei, H TI Photoisomerization of acetyl methyl iminoxy radical in low-temperature argon matrices studied by density functional theory SO CHEMICAL PHYSICS LETTERS LA English DT Article ID OXYGEN-ATOM TRANSFER; NO2 DISSOCIATION THRESHOLD; LIGHT-INDUCED REACTION; VISIBLE-LIGHT; CRYOGENIC MATRIX; NITROGEN-DIOXIDE; INFRARED-SPECTRA; DFT CALCULATION; RED-LIGHT; AR MATRIX AB Photoisomerization of acetyl methyl iminoxy radical produced from NO2 and 2-butyne in low-temperature argon matrices has been studied by density functional theory (DFT) calculation. The infrared bands observed upon 585 nm irradiation are assigned, using the spectral patterns predicted by DFT, to the trans-trans, cis-trans, and cis-cis conformers, where the former and latter conformations refer to the CO-CN and C=N bond axes, respectively. Conformational isomerization around the C=N bond is found to occur upon 515 nm irradiation. The isomerization mechanism is discussed with the aid of the DFT calculation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Tokyo Univ Agr & Technol, Grad Sch Bioapplicat & Syst Engn, Koganei, Tokyo 1848588, Japan. Lawrence Berkeley Natl Lab, Phys Biosci Div, MS Calvin Lab, Berkeley, CA 94720 USA. RP Nakata, M (reprint author), Tokyo Univ Agr & Technol, Grad Sch Bioapplicat & Syst Engn, 2-24-16 Naka Cho, Koganei, Tokyo 1848588, Japan. RI Nakata, Munetaka/C-2127-2013; Takayanagi, Masao/E-7100-2013 NR 33 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD SEP 29 PY 2000 VL 328 IS 3 BP 283 EP 290 DI 10.1016/S0009-2614(00)00937-4 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 362JX UT WOS:000089775800007 ER PT J AU Ginalski, K Venclovas, C Lesyng, B Fidelis, K AF Ginalski, K Venclovas, C Lesyng, B Fidelis, K TI Structure-based sequence alignment for the beta-trefoil subdomain of the clostridial neurotoxin family provides residue level information about the putative ganglioside binding site SO FEBS LETTERS LA English DT Article DE tetanus neurotoxin; botulinum neurotoxin; beta-trefoil; sequence alignment; homology modeling; ganglioside binding site ID HEAT-LABILE ENTEROTOXIN; FREE FATTY-ACIDS; RECEPTOR-BINDING; TETANUS TOXIN; BOTULINUM NEUROTOXINS; B NEUROTOXIN; A NEUROTOXIN; IDENTIFICATION; RECOGNITION; TRANSPORT AB Clostridial neurotoxins embrace a family of extremely potent toxins comprised of tetanus toxin (TeNT) and seven different serotypes of botulinum toxin (BoNT/A-G). The beta-trefoil subdomain of the C-terminal part of the heavy chain (Hc), responsible for ganglioside binding, is the most divergent region in clostridial neurotoxins with sequence identity as low as 15%, We re-examined the alignment between family sequences within this subdomain, since in this region all alignments published to date show obvious inconsistencies with the beta-trefoil fold, The final alignment was obtained by considering the general constraints imposed by this fold, and homology modeling studies based on the TeNT structure, Recently solved structures of BoNT/A confirm the validity of this structure-based approach. Taking into account biochemical data and crystal structures of TeNT and BoNT/A, we also re-examined the location of the putative ganglioside binding site and, using the new alignment, characterized this site in other BoNT serotypes, (C) 2000 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved. C1 Univ Warsaw, Inst Expt Phys, Dept Biophys, PL-02089 Warsaw, Poland. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Univ Warsaw, Interdisciplinary Ctr Math & Computat Modelling, PL-02106 Warsaw, Poland. Inst Biotechnol, LT-2028 Vilnius, Lithuania. RP Ginalski, K (reprint author), Univ Warsaw, Inst Expt Phys, Dept Biophys, Zwirki & Wigury 93, PL-02089 Warsaw, Poland. NR 43 TC 38 Z9 39 U1 2 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD SEP 29 PY 2000 VL 482 IS 1-2 BP 119 EP 124 DI 10.1016/S0014-5793(00)01954-2 PG 6 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 361XG UT WOS:000089749100022 PM 11018534 ER PT J AU Pais, P Knize, MG AF Pais, P Knize, MG TI Chromatographic and related techniques for the determination of aromatic heterocyclic amines in foods SO JOURNAL OF CHROMATOGRAPHY B LA English DT Review DE reviews; food analysis; heterocyclic amines ID PERFORMANCE LIQUID-CHROMATOGRAPHY; CIGARETTE-SMOKE CONDENSATE; CAPILLARY-ZONE-ELECTROPHORESIS; TANDEM MASS-SPECTROMETRY; FRIED GROUND-BEEF; ACID PYROLYSIS PRODUCTS; ORTHOGONAL ARRAY DESIGN; SOLID-PHASE EXTRACTION; HEATED MEAT-PRODUCTS; IN-PROCESS FLAVORS AB Some 20 years ago, Japanese scientists discovered a new group of highly toxic compounds, classified as heterocyclic aromatic amines, from broiled and grilled meat and fish products. Numerous studies have shown that most HAs are mutagenic and carcinogenic, and the safety of HA-containing foods has become a concern for the public. To date, more than 20 different mutagenic and/or carcinogenic heterocyclic amines have been identified in foods. This paper reviews the analysis of foods for HAs with 145 references. We survey some of the numerous methods available for the chromatographic analysis of heterocyclic amines and highlight the recent advances. We discuss chromatographic and related techniques, including capillary electrophoresis, and their coupling to mass spectrometry for the determination of these contaminants in foods. In addition, the review summarises data on the content of HAs in various cooked foods. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Barcelona, Dept Quim Analit, E-08028 Barcelona, Spain. Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. RP Pais, P (reprint author), Euromed SA, C Rec Dalt 8, Barcelona 08100, Spain. FU NCI NIH HHS [CA55861] NR 146 TC 69 Z9 75 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4347 J9 J CHROMATOGR B JI J. Chromatogr. B PD SEP 29 PY 2000 VL 747 IS 1-2 BP 139 EP 169 DI 10.1016/S0378-4347(00)00118-3 PG 31 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 365ND UT WOS:000089956600009 PM 11103904 ER PT J AU Battal, T Inal, OT Rangaswamy, P AF Battal, T Inal, OT Rangaswamy, P TI Residual stress analysis of deuterium irradiated copper coatings SO SCRIPTA MATERIALIA LA English DT Article DE plasma deposition; deuterium; residual stress; X-ray diffraction ID X-RAY-DIFFRACTION; THIN-FILMS; ION IRRADIATION; INTERNAL-STRESS C1 New Mexico Tech, Dept Mat & Met Engn, Socorro, NM 87801 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Battal, T (reprint author), New Mexico Tech, Dept Mat & Met Engn, Socorro, NM 87801 USA. NR 23 TC 2 Z9 2 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD SEP 29 PY 2000 VL 43 IS 8 BP 711 EP 717 DI 10.1016/S1359-6462(00)00472-3 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 362MD UT WOS:000089781000005 ER PT J AU Elmer, JW Wong, J Ressler, T AF Elmer, JW Wong, J Ressler, T TI In-situ observations of phase transformations during solidification and cooling of austenitic stainless steel welds using time-resolved X-ray diffraction SO SCRIPTA MATERIALIA LA English DT Article DE weld solidification; time resolved experiments; X-ray diffraction; stainless steel alloys; in-situ measurements ID HEAT-AFFECTED ZONE; MICROSTRUCTURAL DEVELOPMENT; CRACKING SUSCEPTIBILITY; BEHAVIOR C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Max Planck Soc, Fritz Haber Inst, Dept Inorgan Chem, D-14195 Berlin, Germany. RP Elmer, JW (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. NR 34 TC 58 Z9 58 U1 1 U2 13 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD SEP 29 PY 2000 VL 43 IS 8 BP 751 EP 757 DI 10.1016/S1359-6462(00)00481-4 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 362MD UT WOS:000089781000010 ER PT J AU Bains, AS Gordon, CA Granato, AV Schwarz, RB AF Bains, AS Gordon, CA Granato, AV Schwarz, RB TI The shear modulus of bulk amorphous Pd40Ni40P20 and its relation to viscosity and specific heat SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 12th International Conference on Internal Friction and Ultrasonic Attenuation in Solids (ICIFUAS-12) CY JUL 19-23, 1999 CL BUENOS AIRES, ARGENTINA SP Abdus Salam Int Ctr Theoret Phys, Ctr Ind Res, Comis Nacl Actividades Espaciales, Comis Nacl Energia Atom, Consejo Nacl Invest Cientif & Tecn, Electrargen SRL, Fabr Aleaciones Especiales SA, Fdn Jose A Balseiro, Fdn Desarrikki Technol, Fdn YPF, Leybold Vacuum, Monditec, UNESCO, Vibran Technologies Inc ID STATES; GLASSES; LIQUID AB We have measured the shear modulus and its temperature dependence of Pd-40,Ni40P20 using an EMAT technique. Measurements were made of the temperature dependence at constant heating rate of the infinite frequency shear modulus G. Values of the shear softening parameter gamma are estimated and compared with those obtainable from frequency dependent sheer moduli, specific heat and viscosity measurements. There is overall agreement with the Interstitialcy Theory of Condensed Matter States. (C) 2000 Published by Elsevier Science S.A. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Calif Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RP Bains, AS (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI 苏, 日亮/D-4386-2009 NR 13 TC 13 Z9 13 U1 0 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD SEP 28 PY 2000 VL 310 BP 20 EP 23 DI 10.1016/S0925-8388(00)01004-5 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 357CK UT WOS:000089480800005 ER PT J AU Schwarz, RB Vuorinen, JF AF Schwarz, RB Vuorinen, JF TI Resonant ultrasound spectroscopy: applications, current status and limitations SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 12th International Conference on Internal Friction and Ultrasonic Attenuation in Solids (ICIFUAS-12) CY JUL 19-23, 1999 CL BUENOS AIRES, ARGENTINA SP Abdus Salam Int Ctr Theoret Phys, Ctr Ind Res, Comis Nacl Actividades Espaciales, Comis Nacl Energia Atom, Consejo Nacl Invest Cientif & Tecn, Electrargen SRL, Fabr Aleaciones Especiales SA, Fdn Jose A Balseiro, Fdn Desarrikki Technol, Fdn YPF, Leybold Vacuum, Monditec, UNESCO, Vibran Technologies Inc DE ultrasonics; acoustic properties; amorphous materials ID ELECTROMAGNETIC-ACOUSTIC TRANSDUCTION; ELASTIC-CONSTANTS; FUSED-SILICA; MODES; MONOCRYSTAL; CRYSTALS; SPHERES; SOLIDS; MODULI AB Over the last 10 years, resonant ultrasound spectroscopy (RUS) has become a versatile laboratory technique for measuring second-order elastic constants and ultrasonic attenuation in solids. The technique is based on measuring the spectrum of mechanical resonances for a sample of known shape (usually a parallelepiped). This spectrum cannot be deconvoluted to deduce the elastic constants. Instead, an approximate spectrum is calculated from the known sample dimensions, its mass, and a set of 'guessed' elastic constants. A multidimensional minimization of the error between the measured and calculated spectra enables deducing all the elastic constants of the solid from a single frequency scan. Currently, the technique can be applied to crystals of orthorhombic symmetry (9 elastic constants) or higher using desktop computers and software developed for this purpose. (C) 2000 Published by Elsevier Science S.A. C1 Los Alamos Natl Lab, Div Mat Sci, Los Alamos, NM 87545 USA. Tampere Univ Technol, Inst Mat Sci, SF-33101 Tampere, Finland. RP Schwarz, RB (reprint author), Los Alamos Natl Lab, Div Mat Sci, POB 1663, Los Alamos, NM 87545 USA. EM rxzs@lanl.gov; jvuorine@cc.tut.fi RI Vuorinen, Jyrki/G-4256-2014; OI Vuorinen, Jyrki/0000-0002-7537-1557 NR 48 TC 44 Z9 46 U1 3 U2 17 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 SEP 28 PY 2000 VL 310 BP 243 EP 250 DI 10.1016/S0925-8388(00)00925-7 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 357CK UT WOS:000089480800052 ER PT J AU Laskin, J Futrell, JH AF Laskin, J Futrell, JH TI The theoretical basis of the kinetic method from the point of view of finite heat bath theory SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAS-PHASE BASICITIES; PROTON-BOUND DIMERS; THERMOCHEMICAL DETERMINATIONS; UNIMOLECULAR REACTIONS; ACTIVATED SYSTEMS; BRANCHING RATIOS; THERMAL KINETICS; AMINO-ACIDS; AFFINITIES; DISSOCIATION AB We present a rigorous theoretical basis of the kinetic method, commonly used for thermochemical determinations in mass spectrometry, based on finite heat bath theory (FHBT) developed by Klots. A simple analytical expression for the branching ratio is derived from FHBT formalism. This expression simplifies td the expression given by the absolute reaction rate theory (1) for very large clusters or (2) for reactions having a negligible kinetic shift. The reacting population is described by two different temperatures rather than by the "effective" temperature as suggested previously. Simulations performed using both RRKM and FHBT revealed that the kinetic plots are slightly nonlinear. The observed curvature is related to the changes in the transition state temperature as a function of the critical energy for fragmentation. The curvature of the plots decreases for larger clusters. We show that the "effective" temperature closely resembles the average value of the transition state temperature. This allows us to assign a new definition of the effective temperature and predict its properties. The results of simulations confirm that the extended version of the kinetic method introduced by Fenselau and co-workers provides accurate relative energetics for competitive reactions for both small and large ions. However, accurate thermochemical information can be obtained from the kinetic method only if reactions under investigation have negligible reverse activation energies. A new approach for extracting relative fragmentation energetics and entropy differences for two competing reactions is proposed. This approach requires a measurement of kinetic energy release distributions (KERDs) for the two fragmentation channels; the relative energetics and dynamics can be extracted from a single measurement. C1 Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Laskin, J (reprint author), Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, POB 999 K8-96, Richland, WA 99352 USA. EM Julia.Laskin@pnl.gov RI Laskin, Julia/H-9974-2012 OI Laskin, Julia/0000-0002-4533-9644 NR 38 TC 49 Z9 49 U1 1 U2 4 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 SEP 28 PY 2000 VL 104 IS 38 BP 8829 EP 8837 DI 10.1021/jp001556b PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 358ME UT WOS:000089561200029 ER PT J AU Park, NG van de Lagemaat, J Frank, AJ AF Park, NG van de Lagemaat, J Frank, AJ TI Comparison of dye-sensitized rutile- and anatase-based TiO2 solar cells SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MODULATED PHOTOCURRENT SPECTROSCOPY; NANOSTRUCTURED ZNO ELECTRODES; PHOTOELECTROCHEMICAL CHARACTERIZATION; PHOTOVOLTAIC APPLICATIONS; NANOCRYSTALLINE; TRANSPORT; LIGHT; CONVERSION; OXIDE AB Crack-free nanocrystalline rutile TiO2 films with thicknesses of up to 12 mu m were prepared and characterized in connection with their application to dye-sensitized solar cells. The photoelectrochemical properties of the rutile-based solar cell are compared with those of the anatase-based cell. Scanning electron microscopy (SEM) shows that the rutile films consist of homogeneously distributed rod-shaped particles with an average dimension of 20 x 80 nm. Both the thickness and the morphology of the rutile films have a strong influence on the photoelectrochemical properties of the solar cells. Measurements of the incident monochromatic photon-to-current conversion efficiency (IPCE) as a function of film thickness imply that a significant fraction of light in the spectral region below 600 nm is absorbed in the first few microns of the dye-covered films due to strong light absorption by the dye. At longer wavelengths, where the dye absorbs weakly, the IPCE increases in direct proportion to the film thickness, suggesting that the electron-injection rate throughout the cell approaches homogeneity. The open-circuit photovoltage (V-oc) shows only a small change with film thickness, which is attributed to the compensating effect associated with the dependence of the number of dye molecules and recombination centers on the surface area. For the same film thickness, the photocurrent-voltage responses of the dye-sensitized rutile and anatase films at one-sun Light intensity are remarkably close. Their V-oc is essentially the same, whereas the short-circuit photocurrent of the rutile-based cell is only about 30% lower than that of the anatase-based cell. The lower photocurrent of the rutile film correlates with a lesser amount of adsorbed dye, owing to a smaller surface area per unit volume compared with that of the anatase film. Intensity-modulated photocurrent spectroscopy and SEM studies indicate that electron transport is slower in the rutile layer than in the anatase layer due to differences in the extent of interparticle connectivity associated with the particle packing density. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Park, NG (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI van de Lagemaat, Jao/J-9431-2012; Wei, Zhanhua/D-7544-2013; Park, Nam-Gyu/F-2477-2014 OI Wei, Zhanhua/0000-0003-2687-0293; NR 26 TC 796 Z9 818 U1 26 U2 334 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 SEP 28 PY 2000 VL 104 IS 38 BP 8989 EP 8994 DI 10.1021/jp994365l PG 6 WC Chemistry, Physical SC Chemistry GA 358MG UT WOS:000089561400013 ER PT J AU Diamant, R Huotari, S Hamalainen, K Sharon, R Kao, CC Deutsch, M AF Diamant, R Huotari, S Hamalainen, K Sharon, R Kao, CC Deutsch, M TI The L alpha ' satellite of tungsten SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID X-RAY-SATELLITES; SPECTRA; CU; PHOTOIONIZATION; THRESHOLD; EVOLUTION; ELEMENTS; ENERGY; ATOMS AB The first high-resolution measurement of a satellite line in tungsten, L alpha', is presented. The peak energy is (8413.3 +/- 0.4) eV and the satellite intensity is (3.0 +/- 0.6) x 10(-3) of that of the diagram L alpha(1,2) spectrum. The line shape is also determined. Evidence is presented to demonstrate that the original assignment of this line to the M(3) spectator hole transition 2P(3/2)3P(3/2) --> 3p(3/2)3d(5/2) may have to be revised to that of the M(5) spectator transition 2p(3/2)3d(5/2) --> (3d(5/2))(2). C1 Bar Ilan Univ, Dept Phys, IL-52900 Ramat Gan, Israel. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. RP Deutsch, M (reprint author), Bar Ilan Univ, Dept Phys, IL-52900 Ramat Gan, Israel. EM deutsch@mail.biu.ac.il RI Hamalainen, Keijo/A-3986-2010 OI Hamalainen, Keijo/0000-0002-9234-9810 NR 23 TC 7 Z9 7 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD SEP 28 PY 2000 VL 33 IS 18 BP L649 EP L653 DI 10.1088/0953-4075/33/18/103 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 364YX UT WOS:000089922600003 ER PT J AU Pines, D AF Pines, D TI Science-based security under threat - Los Alamos National Laboratory is an endangered national treasure. SO NATURE LA English DT Editorial Material C1 Univ Calif Los Alamos Natl Lab, Inst Complex Adapt Matter, Los Alamos, NM 87545 USA. RP Pines, D (reprint author), Univ Calif Los Alamos Natl Lab, Inst Complex Adapt Matter, POB 1663, Los Alamos, NM 87545 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD SEP 28 PY 2000 VL 407 IS 6803 BP 447 EP 448 DI 10.1038/35035219 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 361MT UT WOS:000089727400018 PM 11028978 ER PT J AU Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Kopp, S Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D McGee, S Perera, LP Zhou, GJ Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Morrison, RJ Nelson, HN Briere, RA AF Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Kopp, S Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D McGee, S Perera, LP Zhou, GJ Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Morrison, RJ Nelson, HN Briere, RA CA CLEO Collaboration TI Precise measurement of B-0-(B-0)over-bar mixing parameters at the Epsilon(4S) SO PHYSICS LETTERS B LA English DT Article ID INCLUSIVE DECAYS; DETECTOR; CHARM AB We describe a measurement of B-0 - B-0 mixing parameters exploiting a method of partial reconstruction of the decay chains B --> D* (+/-) pi(-/+) and B -> D* (+/-) rho(-/+) . Using 9.6 X 10(6)BB pairs collected at the Cornell Electron Storage Ring, we find chi(d) = 0.198 +/- 0.013 +/- 0.014, /y(d)/ < 0.40 at 95% confidence level, and /R e(epsilon(B))/ < 0.034 at 95% confidence level. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Univ Texas, Austin, TX 78712 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Texas Pan Amer, Edinburg, TX 78539 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Cincinnati, Cincinnati, OH 45221 USA. MIT, Cambridge, MA 02139 USA. RP Behrens, BH (reprint author), Univ Colorado, Boulder, CO 80309 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 22 TC 16 Z9 16 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 28 PY 2000 VL 490 IS 1-2 BP 36 EP 44 DI 10.1016/S0370-2693(00)00990-4 PG 9 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 360EP UT WOS:000089653700006 ER PT J AU Ahle, L Akiba, Y Ashktorab, K Baker, MD Beavis, D Budick, B Chang, J Chasman, C Chen, Z Chu, YY Chujo, T Cumming, J Debbe, R Dunlop, JC Eldredge, W Fleming, K Fung, SY Garcia, E Gushue, S Hamagaki, H Hayano, R Heintzelman, GH Kang, JH Kim, EJ Kumagai, A Kurita, K Lee, JH Lee, YK Miake, Y Mignerey, AC Moulson, M Muentz, C Nagano, K Ogilvie, CA Olness, J Oyama, K Remsberg, L Sako, H Seto, R Shea, J Shigaki, K Steadman, SG Stephans, GSF Tamagawa, T Tannenbaum, MJ Ueno-Hayashi, S Videbaek, F Xiang, H Wang, F Yagi, K Zhu, F Back, BB Betts, RR Chang, J Chang, WC Chi, CY Chu, YY Cumming, JB Dunlop, JC Eldredge, W Fung, SY Ganz, R Garcia, E Gillitzer, A Heintzelman, GH Henning, WF Hofman, DJ Holzman, B Kang, JH Kim, EJ Kim, SY Kwon, Y McLeod, D Mignerey, AC Moulson, M Nanal, V Ogilvie, CA Pak, R Ruangma, A Russ, D Seto, R Stanskas, PJ Stephans, GSF Wang, H Wolfs, FLH Wuosmaa, AH Xiang, H Xu, GH Yao, HB Zou, CM AF Ahle, L Akiba, Y Ashktorab, K Baker, MD Beavis, D Budick, B Chang, J Chasman, C Chen, Z Chu, YY Chujo, T Cumming, J Debbe, R Dunlop, JC Eldredge, W Fleming, K Fung, SY Garcia, E Gushue, S Hamagaki, H Hayano, R Heintzelman, GH Kang, JH Kim, EJ Kumagai, A Kurita, K Lee, JH Lee, YK Miake, Y Mignerey, AC Moulson, M Muentz, C Nagano, K Ogilvie, CA Olness, J Oyama, K Remsberg, L Sako, H Seto, R Shea, J Shigaki, K Steadman, SG Stephans, GSF Tamagawa, T Tannenbaum, MJ Ueno-Hayashi, S Videbaek, F Xiang, H Wang, F Yagi, K Zhu, F Back, BB Betts, RR Chang, J Chang, WC Chi, CY Chu, YY Cumming, JB Dunlop, JC Eldredge, W Fung, SY Ganz, R Garcia, E Gillitzer, A Heintzelman, GH Henning, WF Hofman, DJ Holzman, B Kang, JH Kim, EJ Kim, SY Kwon, Y McLeod, D Mignerey, AC Moulson, M Nanal, V Ogilvie, CA Pak, R Ruangma, A Russ, D Seto, R Stanskas, PJ Stephans, GSF Wang, H Wolfs, FLH Wuosmaa, AH Xiang, H Xu, GH Yao, HB Zou, CM CA E866 Collaboration E917 Collaboration TI An excitation function of K- and K+ production in Au plus Au reactions at the AGS SO PHYSICS LETTERS B LA English DT Article ID HEAVY-ION COLLISIONS; NUCLEUS-NUCLEUS COLLISIONS; SUBTHRESHOLD ANTIKAON PRODUCTION; AU+AU COLLISIONS; KAON PRODUCTION; BEAM ENERGIES; 11.6A GEV/C; MATTER; DISTRIBUTIONS; MULTIPLICITY AB Mid-rapidity spectra and yields of K- and K+ have been measured for Au + Au collisions at 4, 6, 8, and 10.7 AGeV. The K- yield increases faster with beam energy than for K+ and hence the K-/K+ ratio increases with beam energy. This ratio is studied as a function of both root s and root s - root s(th) which allows the direct comparison of the kaon yields with respect to the production threshold in p + p reactions. For equal root s - root s(th) the measured ratio K-/K+ = 0.2 at energies above threshold in contrast to the K-/K+ ratio of near unity observed at energies below threshold. The use of the K-=/K* ratio to test the predicted changes of kaon properties in dense nuclear matter is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 MIT, Cambridge, MA 02139 USA. NYU, New York, NY USA. Univ Rochester, Rochester, NY 14627 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Columbia Univ, Nevis Labs, Irvington, NY 10533 USA. Univ Illinois, Chicago, IL 60607 USA. High Energy Accelerator Res Org KEK, Tanashi, Tokyo 188, Japan. Johns Hopkins Univ, Baltimore, MD USA. Univ Maryland, College Pk, MD 20742 USA. High Energy Accelerator Res Org KEK, Tsukuba, Ibaraki 305, Japan. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Univ Tokyo, Sch Sci, Ctr Nucl Study, Tanashi, Tokyo 188, Japan. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Yonsei Univ, Seoul 120749, South Korea. RP Ogilvie, CA (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM cogilvie@iastate.edu RI Mignerey, Alice/D-6623-2011; seto, richard/G-8467-2011; Cumming, James/I-3358-2013; Hayano, Ryugo/F-7889-2012; HAMAGAKI, HIDEKI/G-4899-2014; OI Cumming, James/0000-0001-6930-0958; Hayano, Ryugo/0000-0002-1214-7806; Tannenbaum, Michael/0000-0002-8840-5314; Holzman, Burt/0000-0001-5235-6314 NR 31 TC 112 Z9 112 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 28 PY 2000 VL 490 IS 1-2 BP 53 EP 60 DI 10.1016/S0370-2693(00)00916-3 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 360EP UT WOS:000089653700008 ER PT J AU de Gouvea, A Friedland, A Murayama, H AF de Gouvea, A Friedland, A Murayama, H TI The dark side of the solar neutrino parameter space SO PHYSICS LETTERS B LA English DT Article ID OSCILLATIONS; FLUX AB Results of neutrino oscillation experiments have always been presented on the (sin(2)2 theta, Delta m(2)) parameter space for the case of two-flavor oscillations. We point out, however, that this parameterization misses the half of the parameter space pi/4 < theta less than or equal to pi/2 ('the dark side'), which is physically inequivalent to the region 0 less than or equal to theta less than or equal to pi/4 ('the light side') in the presence of matter effects. The MSW solutions to the solar neutrino problem can extend to the dark side, especially if we take the conservative attitude to allow higher confidence levels, ignore some of the experimental results in the fits, or relax theoretical predictions. Furthermore, even the so-called 'vacuum oscillation' solution distinguishes the dark and the light sides. We urge experimental collaborations to present their results on the entire parameter space. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CERN, Div Theory, CH-1211 Geneva 23, Switzerland. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. RP de Gouvea, A (reprint author), CERN, Div Theory, CH-1211 Geneva 23, Switzerland. RI Murayama, Hitoshi/A-4286-2011 NR 20 TC 101 Z9 101 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 SEP 28 PY 2000 VL 490 IS 1-2 BP 125 EP 130 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 360EP UT WOS:000089653700016 ER PT J AU Michelsen, HA Irion, FW Manney, GL Toon, GC Gunson, MR AF Michelsen, HA Irion, FW Manney, GL Toon, GC Gunson, MR TI Features and trends in Atmospheric Trace Molecule Spectroscopy (ATMOS) version 3 stratospheric water vapor and methane measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL LOWER STRATOSPHERE; TOTAL HYDROGEN BUDGET; UARS HALOE DATA; POLAR VORTEX; ATMOS/ATLAS-3 MEASUREMENTS; ANTARCTIC STRATOSPHERE; DEHYDRATION MECHANISM; FOUNTAIN HYPOTHESIS; SEASONAL-VARIATIONS; AGE SPECTRA AB Mixing ratios of water vapor entering the stratosphere are inferred from Atmospheric Trace Molecule Spectroscopy (ATMOS) measurements to be 3.28 ppm in 1985, 3.53 ppm in 1992, 3.67 ppm in 1993, and 3.65 ppm in 1994, yielding an average increase of 0.041 +/- 0.007 (1 sigma) ppm/yr or 1.2 +/- 0.2%/yr between 1985 and 1994. Strong evidence for a seasonal cycle in water vapor is apparent below 45 km in the tropics, and ascent rates derived from these tropical profiles are comparable to previous estimates. An enhancement in the sum [H2O] + 2[CH4] apparent between 45 and 60 km in the tropics appears to be consistent with remnants of a seasonal cycle in [H2O]. C1 Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sandia Natl Labs, Combust Res Facil, MS 9055,POB 969, Livermore, CA 94551 USA. EM hamiche@ca.sandia.gov; fwi@caesar.jpl.nasa.gov; manney@mls.jpl.nasa.gov; toon@mark4sun.jpl.nasa.gov; mrg@caesar.jpl.nasa.gov NR 86 TC 35 Z9 36 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 27 PY 2000 VL 105 IS D18 BP 22713 EP 22724 DI 10.1029/2000JD900336 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 359EF UT WOS:000089598000004 ER PT J AU Fast, JD Doran, JC Shaw, WJ Coulter, RL Martin, TJ AF Fast, JD Doran, JC Shaw, WJ Coulter, RL Martin, TJ TI The evolution of the boundary layer and its effect on air chemistry in the Phoenix area SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLOSURE-MODEL; OZONE LAYERS; TURBULENCE; VALLEY AB During a 4-week period in May and June of 1998, meteorological and chemical measurements were made as part of a field campaign carried out in the Phoenix area. Data from the field campaign provide the first detailed measurements of the properties of the convective boundary layer in this area and of the effects of these properties on ozone levels. The meteorological and chemical measurements have been combined with results from a set of meteorological, particle, and chemistry models to study ozone production, transport, and mixing in the vicinity of Phoenix. Good agreement between the simulations and observations was obtained, and the results have been used to illustrate several important factors affecting ozone patterns in the region. Heating of the higher terrain north and east of Phoenix regularly produced thermally driven circulations from the south and southwest through most of the boundary layer during the afternoon, carrying the urban ozone plume to the northeast. The combination of deep mixed layers and moderate winds aloft provided good ventilation of the Phoenix area On most days so that multiday buildups of locally produced ozone did not appear to contribute significantly to ozone levels during the study period. Sensitivity simulations determined that 20 to 40% of the afternoon surface atone mixing ratios (corresponding to 15 to 35 ppb) were due to vertical mixing processes that entrained reservoirs of ozone into the growing convective boundary layer. The model results also indicated that ozone production in the region is volatile organic compound limited. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Pacific NW Natl Lab, 902 Battelle Blvd,POB 999, Richland, WA 99352 USA. EM jerome.fast@pnl.gov; christopher.doran@pnl.gov; will.shaw@pnl.gov NR 27 TC 49 Z9 49 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 27 PY 2000 VL 105 IS D18 BP 22833 EP 22848 DI 10.1029/2000JD900289 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 359EF UT WOS:000089598000013 ER PT J AU Goodson, DZ Roelse, DW Chiang, WT Valone, SM Doll, JD AF Goodson, DZ Roelse, DW Chiang, WT Valone, SM Doll, JD TI A simple method for calculating quantum effects on the temperature dependence of bimolecular reaction rates: Application to H-2+H -> H+H-2 and CH4+H -> CH3+H-2 SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID TRANSITION-STATE THEORY; THERMAL RATE CONSTANTS; SCATTERING-THEORY; SELF-DIFFUSION; DYNAMICS; HYDROGEN; ISOTOPE; DEUTERIUM; SURFACE; H-2 AB The temperature dependence of thermal rate constants for hydrogen atom abstraction reactions is studied using transition-state theory with temperature-dependent effective potential energy functions derived from a quantum mechanical path integral analysis with a low-temperature correction. The-theory uses temperature-dependent activation energies determined from Gaussian averages of an empirical potential. Simple analytic expressions are obtained for rate constants. To test the theory the rate constant for H-2 + H is calculated, and the predicted curvature of the Arrhenius plot is shown to agree with results from accurate quantum scattering calculations. The predicted curvature for CH4 + H is compared with experimental results and shown to give better agreement with the observed temperature dependence than do commonly used empirical fits. The expression k(T) = aT exp[-E-0 + E1Teff-1 + E2Teff-3/2)/RT], with T-eff = T + T-0, is suggested for the rate constant for CH4 + H, with the parameters a, E-0, E-1, E-2, and T-0 obtained from theory rather than by fitting to the experimental reaction rates. C1 So Methodist Univ, Dept Chem, Dallas, TX 75275 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MST8, Los Alamos, NM 87545 USA. Brown Univ, Dept Chem, Providence, RI 02912 USA. RP Goodson, DZ (reprint author), So Methodist Univ, Dept Chem, Dallas, TX 75275 USA. NR 46 TC 6 Z9 6 U1 0 U2 1 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 SEP 27 PY 2000 VL 122 IS 38 BP 9189 EP 9195 DI 10.1021/ja000674+ PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 359GP UT WOS:000089603400017 ER PT J AU Chen, LH Xu, S McBranch, D Whitten, D AF Chen, LH Xu, S McBranch, D Whitten, D TI Tuning the properties of conjugated polyelectrolytes through surfactant complexation SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTROACTIVE COMPLEXES; POLYANILINE; POLYMERS; SOLVENTS C1 Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. LLC, QTL Biosyst, Santa Fe, NM 87501 USA. RP Chen, LH (reprint author), Los Alamos Natl Lab, Biosci Div, POB 1663, Los Alamos, NM 87545 USA. NR 23 TC 222 Z9 227 U1 7 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD SEP 27 PY 2000 VL 122 IS 38 BP 9302 EP 9303 DI 10.1021/ja001248r PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 359GP UT WOS:000089603400033 ER PT J AU Ji, HF Dabestani, R Brown, GM AF Ji, HF Dabestani, R Brown, GM TI A supramolecular fluorescent probe, activated by protons to detect cesium and potassium ions, mimics the function of a logic gate SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ALKALI-METAL IONS; MOLECULAR WIRES; RECOGNITION; TRANSPORT; MEMBRANE; SWITCHES; SENSORS; CHARGE; DEVICE; SHIFT 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,MS-6100, Oak Ridge, TN 37831 USA. EM dabestanir@ornl.gov NR 35 TC 117 Z9 119 U1 2 U2 17 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 SEP 27 PY 2000 VL 122 IS 38 BP 9306 EP 9307 DI 10.1021/ja000012k PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 359GP UT WOS:000089603400035 ER PT J AU Morrow, JA Segall, ML Lund-Katz, S Phillips, MC Knapp, M Rupp, B Weisgraber, KH AF Morrow, JA Segall, ML Lund-Katz, S Phillips, MC Knapp, M Rupp, B Weisgraber, KH TI Differences in stability among the human apolipoprotein E isoforms determined by the amino-terminal domain SO BIOCHEMISTRY LA English DT Article ID LOW-DENSITY-LIPOPROTEIN; RECEPTOR-BINDING DOMAIN; GUANIDINE-HYDROCHLORIDE DENATURATION; CYSTEINE-ARGININE INTERCHANGE; THROMBIN-CLEAVAGE FRAGMENT; HUMAN-PLASMA-LIPOPROTEINS; ONSET ALZHEIMER-DISEASE; CENTRAL NERVOUS-SYSTEM; HUMAN-E APOPROTEIN; MYOCARDIAL-INFARCTION AB Denaturation by guanidine-HCl, urea, or heating was performed on the common isoforms of human apolipoprotein (apo) E (apoE2, apoE3, and apoE4) and their 22-kDa and 10-kDa fragments in order to investigate the effects of the cysteine/arginine interchanges at residues 112 and 158. Previous physical characterization of apoE3 established that apoE contains two domains, the 10-kDa carboxyl-terminal and 22-kDa amino-terminal domains, which unfold independently and exhibit large differences in stability. However, the physical properties of apoE2, apoE3, and apoE4 have not been compared before. Analysis by circular dichroism showed that the different isoforms have identical ct-helical contents and guanidine-HCl denaturation confirmed that the two domains unfold independently in all three isoforms. However, guanidine-HCl, urea, and thermal denaturation showed differences in stability among the 22-kDa amino-terminal fragments of the apoE isoforms (apoE4 < apoE3 < apoE2). Furthermore, guanidine-HCl denaturation monitored by circular dichroism and fluorescence suggested the presence of a folding intermediate in apoE, most prominently in apoE4. Thus, these studies reveal that the major isoforms of apoE, which are associated with different pathological consequences, exhibit significant differences in stability. C1 Univ Calif San Francisco, Gladstone Inst Neurol Dis, Inst Cardiovasc Res, Dept Pathol, San Francisco, CA 94140 USA. Med Coll Penn & Hahnemann Univ, Dept Biochem, Philadelphia, PA 19129 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Weisgraber, KH (reprint author), Univ Calif San Francisco, Gladstone Inst Neurol Dis, Inst Cardiovasc Res, Dept Pathol, San Francisco, CA 94140 USA. FU NHLBI NIH HHS [HL41633, HL56083]; NINDS NIH HHS [NS35939] NR 91 TC 194 Z9 195 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 26 PY 2000 VL 39 IS 38 BP 11657 EP 11666 DI 10.1021/bi000099m PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 359DL UT WOS:000089596200015 PM 10995233 ER PT J AU Eberling, JL Reed, BR Coleman, JE Jagust, WJ AF Eberling, JL Reed, BR Coleman, JE Jagust, WJ TI Effect of estrogen on cerebral glucose metabolism in postmenopausal women SO NEUROLOGY LA English DT Article ID COGNITIVE FUNCTION; MEMORY; DEMENTIA; THERAPY AB PET was used to evaluate the effect of estrogen use on regional cerebral glucose metabolism in postmenopausal women. Women receiving estrogen replacement therapy (ERT+), women not receiving estrogen (ERT-), and women with AD were studied. The ERT- group showed metabolic ratios that were intermediate to the ERT+ and AD groups, although they did not show any signs of cognitive impairment. These findings show an effect of estrogen depletion on brain metabolic activity. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Neurol, Davis, CA 95616 USA. Univ Calif Davis, Alzheimers Dis Ctr, Davis, CA 95616 USA. RP Eberling, JL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, 1 Cyclotron Rd,Mail Stop 55-121, Berkeley, CA 94720 USA. FU NIA NIH HHS [AG10129, AG07793] NR 9 TC 37 Z9 39 U1 1 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0028-3878 J9 NEUROLOGY JI Neurology PD SEP 26 PY 2000 VL 55 IS 6 BP 875 EP 877 PG 3 WC Clinical Neurology SC Neurosciences & Neurology GA 357ED UT WOS:000089484800026 PM 10994014 ER PT J AU Schiffer, JP Drewsen, M Hangst, JS Hornekaer, L AF Schiffer, JP Drewsen, M Hangst, JS Hornekaer, L TI Temperature, ordering, and equilibrium with time-dependent confining forces SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID LASER-COOLED IONS; LINEAR PAUL TRAP; NORMAL-MODES; TRANSITION; CRYSTALS; PLASMAS; CHAOS; PHASE AB The concepts of temperature and equilibrium are not well defined in systems of particles with time-varying external forces. An example is a radio frequency ion trap, with the ions laser cooled into an ordered solid, characteristic of sub-mK temperatures. whereas the kinetic energies associated with the fast coherent motion in the trap are up to 7 orders of magnitude higher. Simulations with 1.000 ions reach equilibrium between the degrees of freedom when only aperiodic displacements (secular motion) are considered. The coupling of the periodic driven motion associated with the confinement to the nonperiodic random motion of the ions is very small at low temperatures and increases quadratically with temperature. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus, Denmark. RP Schiffer, JP (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 19 TC 39 Z9 40 U1 0 U2 5 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 SEP 26 PY 2000 VL 97 IS 20 BP 10697 EP 10700 DI 10.1073/pnas.190320397 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 358PH UT WOS:000089566100008 PM 10995471 ER PT J AU Pickering, IJ Prince, RC Salt, DE George, GN AF Pickering, IJ Prince, RC Salt, DE George, GN TI Quantitative, chemically specific imaging of selenium transformation in plants SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID MICRO-XANES SPECTROSCOPY; INDIAN MUSTARD; REDUCTASE; SELENATE; SPECIATION; TRANSPORT; TOLERANCE; SAMPLES AB Quantitative, chemically specific images of biological systems would be invaluable in unraveling the bioinorganic chemistry of biological tissues. Here we report the spatial distribution and chemical forms of selenium in Astragalus bisulcatus (two-grooved poison or milk vetch), a plant capable of accumulating up to 0.65% of its shoot dry biomass as Se in its natural habitat. By selectively tuning incident x-ray energies close to the Se K-absorption edge, we have collected quantitative. 100-mu m-resolution images of the spatial distribution, concentration, and chemical form of Se in intact root and shoot tissues. To our knowledge, this is the first report of quantitative concentration-imaging of specific chemical forms. Plants exposed to 5 mu M selenate for 28 days contained predominantly selenate in the mature leaf tissue at a concentration of 0.3-0.6 mM, whereas the young leaves and the roots contained organoselenium almost exclusively, indicating that the ability to biotransform selenate is either inducible or developmentally specific. While the concentration of organoselenium in the majority of the root tissue was much lower than that of the youngest leaves (0.2-0.3 compared with 3-4 mM). isolated areas on the extremities of the roots contained concentrations of organoselenium an order of magnitude greater than the rest of the root. These imaging results were corroborated by spatially resolved x-ray absorption near-edge spectra collected from selected 100 x 100 mu m(2) regions of the same tissues. C1 ExxonMobil Res & Engn Co, Annandale, NJ 08801 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. No Arizona Univ, Dept Chem, Flagstaff, AZ 86011 USA. RP Pickering, IJ (reprint author), ExxonMobil Res & Engn Co, Annandale, NJ 08801 USA. RI Salt, David/B-3864-2009; George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Pickering, Ingrid/0000-0002-0936-2994 NR 29 TC 131 Z9 137 U1 3 U2 33 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 SEP 26 PY 2000 VL 97 IS 20 BP 10717 EP 10722 DI 10.1073/pnas.200244597 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 358PH UT WOS:000089566100012 PM 10984519 ER PT J AU Walla, PJ Linden, PA Hsu, CP Scholes, GD Fleming, GR AF Walla, PJ Linden, PA Hsu, CP Scholes, GD Fleming, GR TI Femtosecond dynamics of the forbidden carotenoid S-1 state in light-harvesting complexes of purple bacteria observed after two-photon excitation SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID PIGMENT-PROTEIN COMPLEXES; LH2 ANTENNA COMPLEXES; ENERGY-TRANSFER; RHODOBACTER-SPHAEROIDES; RHODOPSEUDOMONAS-ACIDOPHILA; CRYSTAL-STRUCTURE; EXCITED-STATES; RPS-ACIDOPHILA; BACTERIOCHLOROPHYLL; SPHEROIDENE AB Time-resolved excited-state absorption intensities after direct two-photon excitation of the carotenoid S-1 state are reported for light-harvesting complexes of purple bacteria. Direct excitation of the carotenoid S-1 state enables the measurement of subsequent dynamics on a fs time scale without interference from higher excited states, such as the optically allowed S-2 state or the recently discovered dark state situated between S-1 and S-2. The lifetimes of the carotenoid S-1 states in the B800-B850 complex and B800-B820 complex of Rhodopseudomonas acidophila are 7 +/- 0.5 ps and 6 +/- 0.5 ps, respectively, and in the light-harvesting complex 2 of Rhodobacter sphaeroides approximate to 1.9 +/- 0.5 ps. These results explain the differences in the carotenoid to bacteriochlorophyll energy transfer efficiency after S-2 excitation. In Rps. acidophila the carotenoid S-1 to bacteriochlorophyll energy transfer is found to be quite inefficient (phi(ET1) <28%) whereas in Rb. sphaeroides this energy transfer is very efficient (phi(ET1) approximate to 80%) The results are rationalized by calculations of the ensemble averaged time constants. We find that the Car S-1 --> B800 electronic energy transfer (EET) pathway (approximate to 85%) dominates over Car S-1 --> B850 EET (approximate to 15%) in Rb. sphaeroides, whereas in Rps. acidophile the Car S-1 --> B850 EET (approximate to 60%) is more efficient than the Car S-1 --> B800 EET (approximate to 40%). The individual electronic couplings for the Car S-1 --> BChl energy transfer are estimated to be approximately 5-26 cm(-1). A major contribution to the difference between the energy transfer efficiencies can be explained by different Car S-1 energy gaps in the two species. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Fleming, GR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Hsu, Chao-Ping/E-1303-2011 OI Hsu, Chao-Ping/0000-0002-7187-427X NR 41 TC 105 Z9 109 U1 1 U2 20 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 SEP 26 PY 2000 VL 97 IS 20 BP 10808 EP 10813 DI 10.1073/pnas.190230097 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 358PH UT WOS:000089566100028 PM 10984512 ER PT J AU Hlavacek, WS Stilianakis, NI Notermans, DW Danner, SA Perelson, AS AF Hlavacek, WS Stilianakis, NI Notermans, DW Danner, SA Perelson, AS TI Influence of follicular dendritic cells on decay of HIV during antiretroviral therapy SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID DYNAMICS IN-VIVO; LYMPHOID-TISSUE; PERIPHERAL-BLOOD; RAPID TURNOVER; T-LYMPHOCYTES; LIFE-SPAN; INFECTION; PLASMA; CLEARANCE; ANTIGEN AB Drug treatment of HIV type 1 (HIV-1) infection leads to a rapid initial decay of plasma virus followed by a slower second phase of decay. To investigate the role of HIV-1 retained on follicular dendritic cells (FDCs) in this process, we have developed and analyzed a mathematical model for HIV-1 dynamics in lymphoid tissue (LT) that includes FDCs. Analysis of clinical data using this model indicates that decay of HIV-1 during therapy may be influenced by release of FDC-associated virus. The biphasic character of viral decay can be explained by reversible multivalent binding of HIV-1 to receptors on FDCs, indicating that the second phase of decay is not necessarily caused by long-lived or latently infected cells. Furthermore. viral clearance and death of short-lived productively infected cells may be faster than previously estimated. The model, with reasonable parameter values, is consistent with kinetic measurements of viral RNA in plasma, viral RNA on FDCs, productively infected cells in LT. and CD4(+) T cells in LT during therapy. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Tubingen, Dept Med Biometry, D-72070 Tubingen, Germany. Univ Amsterdam, Acad Med Ctr, Div Infect Dis Trop Med & AIDS, NL-1100 DE Amsterdam, Netherlands. RP Perelson, AS (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-10,MS K710, Los Alamos, NM 87545 USA. FU NCRR NIH HHS [R01 RR006555, RR06555]; NIAID NIH HHS [AI28433, R37 AI028433, R01 AI028433] NR 39 TC 57 Z9 59 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD SEP 26 PY 2000 VL 97 IS 20 BP 10966 EP 10971 DI 10.1073/pnas.190065897 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 358PH UT WOS:000089566100055 PM 10995459 ER PT J AU Balanyuk, AG Gavriljuk, VG Shivanyuk, VN Tyshchenko, AI Rawers, JC AF Balanyuk, AG Gavriljuk, VG Shivanyuk, VN Tyshchenko, AI Rawers, JC TI Mossbauer study and thermodynamic modeling of Fe-C-N alloy SO ACTA MATERIALIA LA English DT Article DE iron-carbon-nitrogen alloys; austenite; Mossbauer spectroscopy; thermodynamics; computer simulation ID IRON-BASE AUSTENITE; CARBON-NITROGEN MARTENSITES; FCC GAMMA-IRON; DIFFRACTION ANALYSIS; SOLID-SOLUTIONS; PRECIPITATION; SPECTROSCOPY AB Mossbauer spectroscopy and Monte Carlo computer simulation have been combined to understand the reason for the solid-solution stability of Fe-0.93 C-0.91 N alloy (mass%). Interstitial concentrations in austenite and ferrite were determined on the basis of X-ray diffraction measurements of the lattice dilatation. The hyperfine structure of Mossbauer spectra was analyzed to identify different atomic configurations in solid solutions and determine their fractions. Thereafter Monte Carlo simulation of the interstitial distribution in ferritic and austenitic solid solutions was performed, and values of the interstitial-interstitial interaction energies were obtained for the first and second coordination spheres in austenite and the first to the fourth coordination spheres in ferrite. Simulation shows that in both austenitic and ferritic phases the interaction of interstitial atoms is characterized by a strong repulsion within the first two coordination spheres. Experimental data and simulated interstitial distributions are consistent and complementary. It is concluded that the absence of interstitial clusters prevents carbide and nitride precipitates and causes the higher thermodynamic stability of Fe-C-N solid solutions as compared with Fe-C and Fe-N ones. (C) 2000 Acm Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Inst Met Phys, UA-03680 Kiev 142, Ukraine. US DOE, Albany Res Ctr, Albany, OR 97321 USA. RP Inst Met Phys, 36 Vernadsky Ave, UA-03680 Kiev 142, Ukraine. RI Gavriljuk, Valentin/E-6107-2016; Tyshchenko, Andrii/F-8296-2016 NR 54 TC 17 Z9 19 U1 2 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD SEP 25 PY 2000 VL 48 IS 15 BP 3813 EP 3821 DI 10.1016/S1359-6454(00)00208-1 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 359VM UT WOS:000089632800001 ER PT J AU Asoka-Kumar, P Hartley, J Howell, R Sterne, PA Nieh, TG AF Asoka-Kumar, P Hartley, J Howell, R Sterne, PA Nieh, TG TI Chemical ordering around open-volume regions in bulk metallic glass Zr(52.5)Ti(5)Al(10)Cu(17.9)Ni(14.6) SO APPLIED PHYSICS LETTERS LA English DT Article ID POSITRON-ANNIHILATION; ALLOYS; LIQUID AB We provide direct experimental evidence for a nonrandom distribution of atomic constituents in Zr(52.5)Ti(5)Al(10)Cu(17.9)Ni(14.6) bulk metallic glass using positron annihilation spectroscopy. The Ti content around the open-volume regions is significantly enhanced at the expense of Ni and Cu. Our results indicate that Ni and Cu atoms closely occupy the volume bounded by their neighboring atoms while Al, Ti, and Zr are less closely packed, and more likely to be associated with the open-volume regions. The overall distribution of elements seen by the positron is not significantly altered by annealing or by crystallization. Theoretical calculations indicate that the observed elemental distribution is not consistent with the known crystalline phases Zr(2)Cu and NiZr(2), while Al(3)Zr(4) shows some of the characteristics seen in the experiment. (C) 2000 American Institute of Physics. [S0003-6951(00)05139-1]. C1 Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. RP Asoka-Kumar, P (reprint author), Lawrence Livermore Natl Lab, Dept Phys, Livermore, CA 94550 USA. EM asokakumar1@1lnl.gov RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 11 TC 39 Z9 39 U1 1 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 25 PY 2000 VL 77 IS 13 BP 1973 EP 1975 AR PII [S0003-6951(00)05139-1] DI 10.1063/1.1313367 PG 3 WC Physics, Applied SC Physics GA 354RW UT WOS:000089344300018 ER PT J AU Bearden, IG Boggild, H Boissevain, J Christiansen, PHL Conin, L Dodd, J Erazmus, B Esumi, S Fabjan, CW Ferenc, D Franz, A Gaardhoje, JJ Hansen, AG Hansen, O Hardtke, D van Hecke, H Holzer, EB Humanic, TJ Hummel, P Jacak, BV Kaimi, K Kaneta, M Kohama, T Kopytine, ML Leltchouk, M Ljubicic, A Lorstad, B Martin, L Medvedev, A Murray, M Ohnishi, H Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Reichold, D Sakaguchi, A Schmidt-Sorensen, J Simon-Gillo, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y Willis, WJ Wolf, KL Xu, N Zachary, DS AF Bearden, IG Boggild, H Boissevain, J Christiansen, PHL Conin, L Dodd, J Erazmus, B Esumi, S Fabjan, CW Ferenc, D Franz, A Gaardhoje, JJ Hansen, AG Hansen, O Hardtke, D van Hecke, H Holzer, EB Humanic, TJ Hummel, P Jacak, BV Kaimi, K Kaneta, M Kohama, T Kopytine, ML Leltchouk, M Ljubicic, A Lorstad, B Martin, L Medvedev, A Murray, M Ohnishi, H Paic, G Pandey, SU Piuz, F Pluta, J Polychronakos, V Potekhin, M Poulard, G Reichold, D Sakaguchi, A Schmidt-Sorensen, J Simon-Gillo, J Sondheim, W Sugitate, T Sullivan, JP Sumi, Y Willis, WJ Wolf, KL Xu, N Zachary, DS TI Antideuteron production in 158A GeV/c Pb plus Pb collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-ION COLLISIONS; PB+PB COLLISIONS; NUCLEAR COLLISIONS; 14.6A GEV/C; LIGHT; DISTRIBUTIONS; BARYON AB The invariant cross section as a function of transverse momentum for antideuterons produced in 158A GeV/c per nucleon Pb + Pb central collisions has been measured by the NA44 experiment at CERN. This measurement, together with a measurement of antiprotons, allows for the determination of the antideuteron coalescence parameter. The extracted coalescence radius is found to agree with the deuteron coalescence radius and radii determined from two particle correlations. C1 Niels Bohr Inst, DK-2100 Copenhagen, Denmark. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Nucl Phys Lab Nantes, F-44072 Nantes, France. Columbia Univ, New York, NY 10027 USA. CERN, CH-1211 Geneva 23, Switzerland. Rudjer Boskovic Inst, Zagreb, Croatia. Ohio State Univ, Columbus, OH 43210 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Lund Univ, S-22362 Lund, Sweden. Texas A&M Univ, College Stn, TX 77843 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Hiroshima Univ, Higashihiroshima 739, Japan. RP Heidelberg Univ, D-69120 Heidelberg, Germany. RI Bearden, Ian/M-4504-2014; OI Bearden, Ian/0000-0003-2784-3094; Gaardhoje, Jens-Jorgen/0000-0001-6122-4698 NR 25 TC 28 Z9 28 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 SEP 25 PY 2000 VL 85 IS 13 BP 2681 EP 2684 DI 10.1103/PhysRevLett.85.2681 PG 4 WC Physics, Multidisciplinary SC Physics GA 356WD UT WOS:000089465100007 ER PT J AU Armstrong, TA Barish, KN Batsouli, S Bennett, SJ Bertaina, M Chikanian, A Coe, SD Cormier, TM Davies, R Dover, CB Fachini, P Fadem, B Finch, LE George, NK Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, R Huang, HZ Jaradat, H Kumar, BS Lainis, T Lajoie, JG Li, Q Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Pless, IA Pope, JK Porile, NT Pruneau, CA Rabin, MSZ Reid, JD Rimai, A Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Slaughter, AJ Smith, GA Tincknell, ML Toothacker, WS Van Buren, G Wohn, FK Xu, Z AF Armstrong, TA Barish, KN Batsouli, S Bennett, SJ Bertaina, M Chikanian, A Coe, SD Cormier, TM Davies, R Dover, CB Fachini, P Fadem, B Finch, LE George, NK Greene, SV Haridas, P Hill, JC Hirsch, AS Hoversten, R Huang, HZ Jaradat, H Kumar, BS Lainis, T Lajoie, JG Li, Q Libby, B Majka, RD Miller, TE Munhoz, MG Nagle, JL Pless, IA Pope, JK Porile, NT Pruneau, CA Rabin, MSZ Reid, JD Rimai, A Rose, A Rotondo, FS Sandweiss, J Scharenberg, RP Slaughter, AJ Smith, GA Tincknell, ML Toothacker, WS Van Buren, G Wohn, FK Xu, Z CA E864 Collaboration TI Antideuteron yield at the AGS and coalescence implications SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-ION COLLISIONS; ANTIPROTON PRODUCTION; MODEL AB dWe present Experiment 864's measurement of invariant antideuteron yields in 11.5A GeV/c Au + Pt collisions. The analysis includes 250 X 10(6) triggers representing 14 X 10(9) 10% central interactions sampled for events with high mass candidates. We find (1/2 pi p(t))d(2)N/dyd(Pt) = 3.5 +/- 1.5(stat)(-0.5)(+0.9) (syst) X 10(-8) GeV-2 c(2) for 1.8 < y < 2.2, [p(t)] = 0.35 GeV/e (y(c.m.) = 1.6) and 3.7 +/- 2.7(stat)(-1.5)(+1.4)(syst) X 10(-8) GeV-2 c(2) for 1.4 < y < 1.8, [p(t)] = 0.26 GeV/c, and a coalescence parameter (B) over bar(2) of 4.1 +/- 2.9(stat)(-2.4)(+2.3)(syst) X 10(-3) CeV(2)c(-3). Implications for coalescence and antimatter annihilation are discussed. C1 Penn State Univ, University Pk, PA 16802 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Columbia Univ, Nevis Lab, Irvington, NY 10533 USA. Iowa State Univ, Ames, IA 50011 USA. Univ Massachusetts, Amherst, MA 01003 USA. MIT, Cambridge, MA 02139 USA. Purdue Univ, W Lafayette, IN 47907 USA. US Mil Acad, W Point, NY 10996 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Wayne State Univ, Detroit, MI 48201 USA. Yale Univ, New Haven, CT 06520 USA. RP Armstrong, TA (reprint author), Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37235 USA. OI Bertaina, Mario Edoardo/0000-0003-1069-1397 NR 22 TC 24 Z9 24 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 SEP 25 PY 2000 VL 85 IS 13 BP 2685 EP 2688 DI 10.1103/PhysRevLett.85.2685 PG 4 WC Physics, Multidisciplinary SC Physics GA 356WD UT WOS:000089465100008 ER PT J AU Svensson, CE Macchiavelli, AO Juodagalvis, A Poves, A Ragnarsson, I Aberg, S Appelbe, DE Austin, RAE Baktash, C Ball, GC Carpenter, MP Caurier, E Clark, RM Cromaz, M Deleplanque, MA Diamond, RM Fallon, P Furlotti, M Galindo-Uribarri, A Janssens, RVF Lane, GJ Lee, IY Lipoglavsek, M Nowacki, F Paul, SD Radford, DC Sarantites, DG Seweryniak, D Stephens, FS Tomov, V Vetter, K Ward, D Yu, CH AF Svensson, CE Macchiavelli, AO Juodagalvis, A Poves, A Ragnarsson, I Aberg, S Appelbe, DE Austin, RAE Baktash, C Ball, GC Carpenter, MP Caurier, E Clark, RM Cromaz, M Deleplanque, MA Diamond, RM Fallon, P Furlotti, M Galindo-Uribarri, A Janssens, RVF Lane, GJ Lee, IY Lipoglavsek, M Nowacki, F Paul, SD Radford, DC Sarantites, DG Seweryniak, D Stephens, FS Tomov, V Vetter, K Ward, D Yu, CH TI Superdeformation in the N = Z nucleus Ar-36: Experimental, deformed mean field, and spherical shell model descriptions SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRON-RICH NUCLEI; HIGH-SPIN STATES; ROTATIONAL BANDS; MONTE-CARLO; CR-48; REGION; GAMMASPHERE; SYSTEMATICS AB A superdeformed rotational band has been identified in Ar-36, linked to known low-spin states, and observed to its high-spin termination at I-pi = 16(+). Cranked Nilsson-Strutinsky and spherical shell model calculations assign the band to a configuration in which four pf-shell orbitals are occupied, leading to a low-spin deformation beta(2) approximate to 0.45. Two major shells are active for both protons and neutrons, yet the valence space remains small enough to be confronted with the shell model. This band thus provides an ideal case to study the microscopic structure of collective rotational motion. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Lund Inst Technol, Dept Math Phys, S-22100 Lund, Sweden. Univ Autonoma Madrid, Dept Fis Teor, E-28049 Madrid, Spain. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Strasbourg 1, CNRS, IN2P3, Inst Rech Subatom, F-67037 Strasbourg 2, France. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Univ Strasbourg 1, Phys Theor Lab, F-67084 Strasbourg, France. RP Svensson, CE (reprint author), Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Lane, Gregory/A-7570-2011; Poves, Alfredo/L-2594-2013; radford, David/A-3928-2015; Carpenter, Michael/E-4287-2015 OI Lane, Gregory/0000-0003-2244-182X; Poves, Alfredo/0000-0001-7539-388X; Carpenter, Michael/0000-0002-3237-5734 NR 28 TC 142 Z9 143 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 25 PY 2000 VL 85 IS 13 BP 2693 EP 2696 DI 10.1103/PhysRevLett.85.2693 PG 4 WC Physics, Multidisciplinary SC Physics GA 356WD UT WOS:000089465100010 ER PT J AU Wilk, PA Gregorich, KE Turler, A Laue, CA Eichler, R Ninov, V Adams, JL Kirbach, UW Lane, MR Lee, DM Patin, JB Shaughnessy, DA Strellis, DA Nitsche, H Hoffman, DC AF Wilk, PA Gregorich, KE Turler, A Laue, CA Eichler, R Ninov, V Adams, JL Kirbach, UW Lane, MR Lee, DM Patin, JB Shaughnessy, DA Strellis, DA Nitsche, H Hoffman, DC TI Evidence for new isotopes of element 107: (266)Bh and (267)Bh SO PHYSICAL REVIEW LETTERS LA English DT Article ID ORGANIC SOLUTIONS; HALF-LIVES; ELECTRODEPOSITION; DISCOVERY; TARGETS AB New neutron rich istotopes (267)(107)Bh and (266)(107)Bh were produced in bombardments of a Bk-249 target with 117-MeV and 123-MeV Ne-22 ions at the Lawrence Berkeley :National Laboratory 88-Inch Cyclotron. Identification was made by observation of correlated alpha-particle decays between the Ph isotopes and their Db and Lr daughters using a rotating wheel system. (267)Bh was produced with a cross section of approximate to 70 pb and decays with a 17(-6)(+14) s half life by emission of alpha z particles with an average energy of 8.83 +/- 0.03 MeV. One atom of (266)Bh was observed, decaying within 1 s by emission of a 9.29-MeV alpha particle. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Univ Bern, Dept Chem & Biochem, CH-3012 Bern, Switzerland. Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA. RP Wilk, PA (reprint author), Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Wilk, Philip/B-5954-2008; Eichler, Robert/G-5130-2011; Turler, Andreas/D-3913-2014 OI Turler, Andreas/0000-0002-4274-1056 NR 19 TC 58 Z9 59 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 SEP 25 PY 2000 VL 85 IS 13 BP 2697 EP 2700 DI 10.1103/PhysRevLett.85.2697 PG 4 WC Physics, Multidisciplinary SC Physics GA 356WD UT WOS:000089465100011 ER PT J AU Sonier, JE Heffner, RH MacLaughlin, DE Nieuwenhuys, GJ Bernal, O Movshovich, R Pagliuso, PG Cooley, J Smith, JL Thompson, JD AF Sonier, JE Heffner, RH MacLaughlin, DE Nieuwenhuys, GJ Bernal, O Movshovich, R Pagliuso, PG Cooley, J Smith, JL Thompson, JD TI mu(+) Knight shift measurements in U0.965Th0.035Be13 single crystals SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY-FERMION SUPERCONDUCTIVITY; PHASE-DIAGRAM; U1-XTHXBE13; UPT3; (U,TH)BE13; UBE13; FIELD; U0.97TH0.03BE13; RESONANCE; CECU2SI2 AB Muon spin rotation (mu SR) measurements of the temperature dependence of the mu(+) Knight shift in single crystals of U0.965Th0.035Be13 have been used to study the static spin susceptibility chi(s) below the transition temperatures T-c1 and T-c2. While an abrupt reduction of chi(s) with decreasing temperature is observed below T-c1, chi(s) does not change below T-c2 sind remains at a value below the normal-state susceptibility chi(n). In the normal state we find an anomalous anisotropic temperature dependence of the transferred hyperfine coupling between the mu(+) spin and the U 5f electrons. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Leiden Univ, Kamerlingh Onnes Lab, NL-2300 RA Leiden, Netherlands. Calif State Univ Los Angeles, Dept Phys, Los Angeles, CA 90032 USA. RP Sonier, JE (reprint author), Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 156, Canada. RI Pagliuso, Pascoal/C-9169-2012; Cooley, Jason/E-4163-2013 NR 34 TC 12 Z9 12 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 SEP 25 PY 2000 VL 85 IS 13 BP 2821 EP 2824 DI 10.1103/PhysRevLett.85.2821 PG 4 WC Physics, Multidisciplinary SC Physics GA 356WD UT WOS:000089465100042 ER PT J AU Ulmeanu, M Serghei, A Mihailescu, IN Budau, P Enachescu, M AF Ulmeanu, M Serghei, A Mihailescu, IN Budau, P Enachescu, M TI C-Ni amorphous multilayers studied by atomic force microscopy SO APPLIED SURFACE SCIENCE LA English DT Article DE multilayer; RF magnetron sputtering deposition; atomic force microscopy; surface roughness; root-mean-square roughness; power spectral density; fractal dimension AB Amorphous C-Ni superlattice films designed as normal-incidence reflector for 5 nm have been grown on quartz substrate by magnetron sputter deposition. A new digital signal processor-based atomic force microscope (AFM) system has been involved in investigating the surface topography of the final surface of the multilayer structure as well as the substrate. In the first step, roughness measurements involving AFM-tips with different radius curvature indicate the C-Ni multilayer surface profile as being in the nanometer and sub-nanometer range, representing a high quality ended surface of the reflectors. In the second step, a study of the roughness distribution using power spectral density functions (PSD) calculated from AFM measurements was performed. The analysis of the amplitudes of the PSD spectra for the multilayer and the substrate surface provided the evidence of the optimized deposition parameters. The shape of the PSD curves for multilayer and substrate reveals fractal profiles with the same distribution of the roughness for both of them, attesting the influence of the substrate on the quality of the reflectors. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Laser Plasma & Radiat Phys, Dept Lasers, Bucharest, Magurele, Romania. Natl Inst Mat Phys, Bucharest, Magurele, Romania. Univ Bucharest, Fac Phys, Bucharest, Romania. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Ulmeanu, M (reprint author), Natl Inst Laser Plasma & Radiat Phys, Dept Lasers, POB MG-36, Bucharest, Magurele, Romania. RI Mihailescu, Ion/A-5403-2011; Enachescu, Marius/C-4963-2011 NR 11 TC 23 Z9 25 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 SEP 22 PY 2000 VL 165 IS 2-3 BP 109 EP 115 DI 10.1016/S0169-4332(00)00362-7 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 344KL UT WOS:000088757700004 ER PT J AU Lloyd, P Berg, O Thiyagarajan, P Trouw, FR Chronister, EL AF Lloyd, P Berg, O Thiyagarajan, P Trouw, FR Chronister, EL TI Methane dynamics in porous xerogels characterized by small-angle and quasielastic neutron scattering SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MOLECULAR-DYNAMICS; ZEOLITE ZSM-5; SILICA; GEL; DIFFUSION; MCM-41; SANS AB The melting behavior of methane adsorbed in a porous silica xerogel has been examined by quasielastic neutron scattering (QENS) from 20 to 115 K. The methane dynamics indicate a heterogeneous xerogel surface with a distribution of rotational and translational diffusion barrier heights from 0.17 to 2.1 kJ/mole. The QENS elastic intensity structure factor indicates that rotational diffusion occurs about a C-2 molecular axis for methane adsorbed in the xerogel. Porous silica and aluminosilica xerogels have also been characterized by small-angle neutron scattering (SANS) and gas adsorption isotherm measurements to determine the porosity, pore size, and tortuosity of the pore network. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. Argonne Natl Lab, IPNS, Argonne, IL USA. RP Chronister, EL (reprint author), Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. NR 34 TC 1 Z9 1 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 SEP 22 PY 2000 VL 328 IS 1-2 BP 203 EP 213 DI 10.1016/S0009-2614(00)00910-6 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 358GC UT WOS:000089549400030 ER PT J AU Zheng, JP Waluk, J Spanget-Larsen, J Blake, DM Radziszewski, JG AF Zheng, JP Waluk, J Spanget-Larsen, J Blake, DM Radziszewski, JG TI Tetrazete (N-4). Can it be prepared and observed? SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MOLECULE; SPECTRUM; MATRIX AB The nitrogen plasma generated by microwave or electrical discharge in gaseous N-2 was quenched on a cold window (6.2-35 K) and resulting matrix was examined by IR and UV-Vis absorption spectroscopies. In samples prepared with N-14(2) we observe a weak infrared transition at 936.7 cm(-1). It shifts to 900.0 cm(-1) when N-15(2) is used. Both peaks do not correlate with any other features in the spectra and are best explained as originating from tetrahedral tetrazetes (N-4). Their positions are compatible with quantum chemical estimates for N-14(4), at 936.0 cm(-1) and N-15(4), at 904.4 cm(-1). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Radziszewski, JG (reprint author), Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. RI Waluk, Jacek/C-8250-2011 NR 22 TC 42 Z9 44 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD SEP 22 PY 2000 VL 328 IS 1-2 BP 227 EP 233 DI 10.1016/S0009-2614(00)00926-X PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 358GC UT WOS:000089549400033 ER PT J AU Volkow, ND Wang, GJ Fowler, JS Logan, J Gatley, JS Pappas, NR Wong, CT Felder, C AF Volkow, ND Wang, GJ Fowler, JS Logan, J Gatley, JS Pappas, NR Wong, CT Felder, C TI Increased activity of the temporal insula in subjects with bradycardia SO LIFE SCIENCES LA English DT Article DE FDG; positron emission tomography; brain metabolism; cardiovascular; pulse ID CORTEX; ORGANIZATION; STIMULATION; PROJECTIONS; ACTIVATION; THALAMUS; NUCLEUS; RAT AB Though it has been postulated that cortical brain regions participate in the regulation of heart rate, their involvement is poorly understood. Using PET and [18] FDG (to measure regional brain glucose metabolism, which serves as an index of brain function) we compared the regional brain metabolic activity between healthy subjects with bradycardia (<60 beats per minute) with those with normal heart rates in the 75-100 beats per minute range. Statistical Parametric Mapping (SPM) analyses revealed significant differences between the groups predominantly localized to the temporal insula, This finding was corroborated by a separate analysis that measured the metabolic activity for each subject in preselected regions located in the temporal insula. Subjects with bradycardia had significantly higher metabolic activity in the right (p < 0.0001) and in the left temporal insula (p < 0.015) than those with normal heart rates. Moreover, resting heart rates were negatively correlated with metabolism in the right (r = -0.77, p < 0.0001) and in the left temporal insula (r = -0,44, p < 0,05). These results corroborate the importance of the temporal insula in the regulation of resting heart rate in humans. The temporal insula is interconnected with limbic brain region and autonomic centers and suggests that this may be a mechanism by which emotional responses regulate heart rate. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. SUNY Stony Brook, Dept Psychiat, Stony Brook, NY 11794 USA. RP Volkow, ND (reprint author), Brookhaven Natl Lab, Dept Med, Upton, NY 11973 USA. FU NIAAA NIH HHS [AA 09481]; NIDA NIH HHS [DA 06 891-02] NR 17 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0024-3205 J9 LIFE SCI JI Life Sci. PD SEP 22 PY 2000 VL 67 IS 18 BP 2213 EP 2220 DI 10.1016/S0024-3205(00)00807-9 PG 8 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA 359TE UT WOS:000089627500007 PM 11045602 ER PT J AU Weber, WJ Ewing, RC AF Weber, WJ Ewing, RC TI Plutonium immobilization and radiation effects SO SCIENCE LA English DT Letter ID DAMAGE; GD2TI2O7 C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA. RP Weber, WJ (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Weber, William/A-4177-2008 OI Weber, William/0000-0002-9017-7365 NR 8 TC 141 Z9 155 U1 2 U2 43 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 SEP 22 PY 2000 VL 289 IS 5487 BP 2051 EP 2052 DI 10.1126/science.289.5487.2051 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 356EG UT WOS:000089430900019 PM 17799393 ER PT J AU Campisi, J AF Campisi, J TI Aging, chromatin, and food restriction - Connecting the dots SO SCIENCE LA English DT Article C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Campisi, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. NR 10 TC 30 Z9 33 U1 0 U2 4 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 SEP 22 PY 2000 VL 289 IS 5487 BP 2062 EP 2063 DI 10.1126/science.289.5487.2062 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 356EG UT WOS:000089430900029 PM 11032557 ER PT J AU Trombka, JI Squyres, SW Bruckner, J Boynton, WV Reedy, RC McCoy, TJ Gorenstein, P Evans, LG Arnold, JR Starr, RD Nittler, LR Murphy, ME Mikheeva, I McNutt, RL McClanahan, TP McCartney, E Goldsten, JO Gold, RE Floyd, SR Clark, PE Burbine, TH Bhangoo, JS Bailey, SH Petaev, M AF Trombka, JI Squyres, SW Bruckner, J Boynton, WV Reedy, RC McCoy, TJ Gorenstein, P Evans, LG Arnold, JR Starr, RD Nittler, LR Murphy, ME Mikheeva, I McNutt, RL McClanahan, TP McCartney, E Goldsten, JO Gold, RE Floyd, SR Clark, PE Burbine, TH Bhangoo, JS Bailey, SH Petaev, M TI The elemental composition of asteroid 433 Eros: Results of the NEAR-Shoemaker x-ray spectrometer SO SCIENCE LA English DT Article ID RENDEZVOUS MISSION; INFRARED SPECTROMETER; MULTISPECTRAL IMAGER; TEMPERATURE; RADIATION; SPECTRUM; PLASMA AB We report major element composition ratios for regions of the asteroid 433 Eros imaged during two solar flares and quiet sun conditions during the period of May to July 2000, Low aluminum abundances for all regions argue against global differentiation of Eros. Magnesium/silicon, aluminum/silicon, calcium/silicon, and iron/silicon ratios are best interpreted as a relatively primitive, chondritic composition. Marked depletions in sulfur and possible aluminum and calcium depletions, relative to ordinary chondrites, may represent signatures of Limited partial melting or impact volatilization. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Cornell Univ, Ithaca, NY 14853 USA. Max Planck Inst Chem, D-55020 Mainz, Germany. Univ Arizona, Dept Planetary Sci, Tucson, AZ 85721 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Mineral Sci, Washington, DC 20560 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Comp Sci Corp, Syst Sci Div, Laurel, MD 20707 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. RP Trombka, JI (reprint author), NASA, Goddard Space Flight Ctr, Code 691, Greenbelt, MD 20771 USA. RI McNutt, Ralph/E-8006-2010; OI McNutt, Ralph/0000-0002-4722-9166; Reedy, Robert/0000-0002-2189-1303 NR 30 TC 89 Z9 91 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD SEP 22 PY 2000 VL 289 IS 5487 BP 2101 EP 2105 DI 10.1126/science.289.5487.2101 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 356EG UT WOS:000089430900037 ER PT J AU Wikoff, WR Liljas, L Duda, RL Tsuruta, H Hendrix, RW Johnson, JE AF Wikoff, WR Liljas, L Duda, RL Tsuruta, H Hendrix, RW Johnson, JE TI Topologically linked protein rings in the bacteriophage HK97 capsid SO SCIENCE LA English DT Article ID 3-DIMENSIONAL STRUCTURE; CONFORMATIONAL-CHANGES; BACTERIAL-VIRUS; CROSS-LINKING; MATURATION; TRANSITIONS; DEAMIDATION; ASPARAGINYL; MOLSCRIPT; RESIDUES AB The crystal structure of the double-stranded DNA bacteriophage HK97 mature empty capsid was determined at 3.6 angstrom resolution. The 660 angstrom diameter icosahedral particle contains 420 subunits with a new fold. The final capsid maturation step is an autocatalytic reaction that creates 420 isopeptide bonds between proteins. Each subunit is joined to two of its neighbors by Ligation of the side-chain Lysine 169 to asparagine 356. This generates 12 pentameric and 60 hexameric rings of covalently joined subunits that loop through each other, creating protein chainmail: topologically linked protein catenanes arranged with icosahedral symmetry. Catenanes have not been previously observed in proteins and provide a stabilization mechanism for the very thin HK97 capsid. C1 Scripps Res Inst, Dept Mol Biol, La Jolla, CA 92037 USA. Uppsala Univ, Ctr Biomed, Dept Cell & Mol Biol, S-75124 Uppsala, Sweden. Univ Pittsburgh, Dept Biol Sci, Pittsburgh, PA 15260 USA. Univ Pittsburgh, Pittsburgh Bacteriophage Inst, Pittsburgh, PA 15260 USA. Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Johnson, JE (reprint author), Scripps Res Inst, Dept Mol Biol, 10550 N Torrey Pines Rd, La Jolla, CA 92037 USA. FU NIAID NIH HHS [AI40101]; NIGMS NIH HHS [GM47795] NR 42 TC 393 Z9 399 U1 3 U2 28 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 SEP 22 PY 2000 VL 289 IS 5487 BP 2129 EP 2133 DI 10.1126/science.289.5487.2129 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 356EG UT WOS:000089430900046 PM 11000116 ER PT J AU Phadke, AS Robinson, BC Barkigia, KM Fajer, J AF Phadke, AS Robinson, BC Barkigia, KM Fajer, J TI Synthesis of benzochlorins and rhodinobenzochlorins SO TETRAHEDRON LA English DT Article DE chlorine and derivatives; photodynamic therapy ID CHLORINS AB The mechanism of the cyclization of meso-(1-hydroxy-2-propenyl)octaethylporphyrin to octaethylbenzochlorin is proposed. Chlorin intermediates were isolated, characterized and then converted to octaethylbenzochlorin. A rhodinobenzochlorin was isolated on demetallation of Ni coprobenzochlorin with methane sulfonic acid and its structure was confirmed by X-ray crystallography. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Miravant Pharmaceut, Goleta, CA 93117 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Phadke, AS (reprint author), Miravant Pharmaceut, 336 Bollay Dr, Goleta, CA 93117 USA. NR 11 TC 8 Z9 8 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0040-4020 J9 TETRAHEDRON JI Tetrahedron PD SEP 22 PY 2000 VL 56 IS 39 BP 7661 EP 7666 DI 10.1016/S0040-4020(00)00692-X PG 6 WC Chemistry, Organic SC Chemistry GA 355XP UT WOS:000089414100004 ER PT J AU Barsky, D Colvin, ME AF Barsky, D Colvin, ME TI Guanine-cytosine base pairs in parallel-stranded DNA: An ab initio study of the keto-amino wobble pair versus the enol-imino minor tautomer pair SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID HYDROGEN-BONDED COMPLEXES; NUCLEIC-ACID BASES; CENTER-DOT-A; DOUBLE HELIX; CRYSTAL-STRUCTURE; B-DNA; THERMODYNAMIC PARAMETERS; ISOCYTOSINE-CYTOSINE; ANTIPARALLEL DUPLEX; FREE-ENERGY AB Doubly hydrogen bonded, "reverse Watson-Crick" thymine-adenine base pairs make possible the formation of parallel-stranded DNA double helices. Although the presence of guanine and cytosine reduces the stability of parallel-stranded DNA, the rather modest experimentally determined reduction in stability (less than 1 kcal/mol for each C-G pair) has been ascribed separately to favorable amino-amino contacts, tautomerizations, and a wobble pair geometry. Earlier studies predicted that favorable amino-amino contacts could yield an interaction energy (gas phase) of about -5 kcal/mol for a twisted, reverse Watson-Crick C-G base pair. It is shown here that either a minor tautomer pairing or a wobble pairing can much more strongly stabilize reversed C-G base pairs. The calculated gas-phase interaction energies of -14 kcal/mol each are comparable to the gas-phase stability of a T-A base pair. Aqueous-phase calculations, however, greatly favor the wobble pair geometry by 9 kcal/mol. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. RP Barsky, D (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, L-448, Livermore, CA 94550 USA. NR 52 TC 29 Z9 29 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 SEP 21 PY 2000 VL 104 IS 37 BP 8570 EP 8576 DI 10.1021/jp001420d PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 355JW UT WOS:000089383400019 ER PT J AU Osadebe, FAN Smith, DL AF Osadebe, FAN Smith, DL TI Simultaneous evaluation of correlated physical parameters using covariance formalism and applications SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article AB The procedure for the simultaneous evaluation of correlated physical parameters using covariance least-squares methodology has been implemented. A versatile computer code has been developed for the execution of the evaluation task and for the solution of a wide range of physical data analysis problems including curve fitting, spectral peak location and decay data analysis. The results of a validatory simultaneous cross section revaluation and of the analysis of titanium decay data carried out with the code are reported. The result of the validation test is in good agreement with the original evaluation by Hayes and Ryves. The decay data have also been analysed using the maximum likelihood method appropriately formulated for a photopeak fed by one decaying nuclide. The result is in good agreement with that obtained via the covariance least-squares method. This confirms the accuracy and consistency of the whole procedure. C1 Obafemi Awolowo Univ, Dept Phys, Ile Ife, Nigeria. Argonne Natl Lab, Div Appl Phys, Argonne, IL 60439 USA. RP Osadebe, FAN (reprint author), Obafemi Awolowo Univ, Dept Phys, Ile Ife, Nigeria. NR 9 TC 0 Z9 0 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD SEP 21 PY 2000 VL 33 IS 18 BP 2333 EP 2337 DI 10.1088/0022-3727/33/18/319 PG 5 WC Physics, Applied SC Physics GA 360NN UT WOS:000089674300021 ER PT J AU Wakayama, T Shinkai, Y Tamashiro, KLK Niida, H Blanchard, DC Blanchard, RJ Ogura, A Tanemura, K Tachibana, M Perry, ACF Colgan, DF Mombaerts, P Yanagimachi, R AF Wakayama, T Shinkai, Y Tamashiro, KLK Niida, H Blanchard, DC Blanchard, RJ Ogura, A Tanemura, K Tachibana, M Perry, ACF Colgan, DF Mombaerts, P Yanagimachi, R TI Ageing - Cloning of mice to six generations SO NATURE LA English DT Article C1 Rockefeller Univ, New York, NY 10021 USA. Univ Hawaii, John A Burns Sch Med, Dept Anat & Reprod Biol, Honolulu, HI 96822 USA. Kyoto Univ, Inst Virus Res, Dept Cell Biol, Sakyo Ku, Kyoto 6068507, Japan. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Hawaii, Bekesy Lab Neurobiol, Honolulu, HI 96822 USA. Natl Inst Infect Dis, Dept Vet Sci, Tokyo 1628640, Japan. RP Wakayama, T (reprint author), Rockefeller Univ, 1230 York Ave, New York, NY 10021 USA. RI Ogura, Atsuo/J-3916-2014; Shinkai, Yoichi/N-3909-2014 OI Ogura, Atsuo/0000-0003-0447-1988; Shinkai, Yoichi/0000-0002-6051-2484 NR 8 TC 153 Z9 168 U1 0 U2 7 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD SEP 21 PY 2000 VL 407 IS 6802 BP 318 EP 319 DI 10.1038/35030301 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 355NA UT WOS:000089390700033 PM 11014179 ER PT J AU Schroder, A Aeppli, G Coldea, R Adams, M Stockert, O von Lohneysen, H Bucher, E Ramazashvili, R Coleman, P AF Schroder, A Aeppli, G Coldea, R Adams, M Stockert, O von Lohneysen, H Bucher, E Ramazashvili, R Coleman, P TI Onset of antiferromagnetism in heavy-fermion metals SO NATURE LA English DT Article ID QUANTUM-CRITICAL-POINT; MAGNETIC CORRELATIONS; LIQUID BEHAVIOR; KONDO LATTICE; CECU6-XAUX; SYSTEMS; FLUCTUATIONS; TEMPERATURE; INSTABILITY; RESISTIVITY AB There are two main theoretical descriptions of antiferromagnets. The first arises from atomic physics, which predicts that atoms with unpaired electrons develop magnetic moments. In a solid, the coupling between moments on nearby ions then yields antiferromagnetic order at low temperatures(1). The second description, based on the physics of electron fluids or 'Fermi liquids', states that Coulomb interactions can drive the fluid to adopt a more stable configuration by developing a spin density wave(2,3). It is at present unknown which view is appropriate at a 'quantum critical point', where the antiferromagnetic transition temperature vanishes(4-7). Here we report neutron scattering and bulk magnetometry measurements of the metal CeCu6-xAux, which allow us to discriminate between the two models. We rnd evidence for an atomically local contribution to the magnetic correlations which develops at the critical gold concentration (x(c) = 0.1), corresponding to a magnetic ordering temperature of zero. This contribution implies that a Fermi-liquid-destroying spin-localizing transition, unanticipated from the spin density wave description, coincides with the antiferromagnetic quantum critical point. C1 Rutgers State Univ, Dept Phys & Astron, Ctr Mat Theory, Piscataway, NJ 08854 USA. Univ Karlsruhe, Inst Phys, D-76128 Karlsruhe, Germany. NEC Corp Ltd, Princeton, NJ 08540 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Rutherford Appleton Lab, CCLRC, ISIS Facil, Didcot OX11 0QX, Oxon, England. Univ Constance, Dept Phys, D-78457 Constance, Germany. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Coleman, P (reprint author), Rutgers State Univ, Dept Phys & Astron, Ctr Mat Theory, POB 849, Piscataway, NJ 08854 USA. EM Coleman@physics.rutgers.edu RI Ramazashvili, Revaz/J-5090-2013 OI Ramazashvili, Revaz/0000-0001-5133-8253 NR 30 TC 413 Z9 413 U1 3 U2 52 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD SEP 21 PY 2000 VL 407 IS 6802 BP 351 EP 355 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 355NA UT WOS:000089390700039 ER PT J AU Okamura, M Tominaka, T Kawaguchi, T Katayama, T Jain, A Muratore, J Morgan, G Willen, E AF Okamura, M Tominaka, T Kawaguchi, T Katayama, T Jain, A Muratore, J Morgan, G Willen, E TI Half-length model of a Siberian snake magnet for RHIC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB For the Relativistic Heavy ion Collider (RHIC) Spin Project, super-conducting helical dipole magnets are being constructed. These magnets will be used in 'Siberian Snakes' and 'Spin Rotators', which manipulate spin direction of proton beams in RHIC. The dipole field in these magnets rotates 360 degrees and is required to reach a magnetic field strength of more than 4.0 T. The bore radius of the coils and the magnetic length of the magnets are 50 and 7400 mm, respectively. To ascertain the performance of these magnets, which are built using a new "coil in a slot" technique, a half-length model has been fabricated and tested. The quench performance, field uniformity and rotation angle have been investigated. The measured values in the model magnet agreed well with field calculations. These results demonstrate the adequacy of the fabrication method adopted in the model magnet. (C) 2000 Elsevier Science B.V. All rights reserved. C1 RIKEN, Beam Phys & Engn Lab, Wako, Saitama 31501, Japan. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Okamura, M (reprint author), RIKEN, Beam Phys & Engn Lab, 2-1 Hirosawa, Wako, Saitama 31501, Japan. NR 2 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 21 PY 2000 VL 452 IS 1-2 BP 53 EP 60 DI 10.1016/S0168-9002(00)00426-5 PG 8 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 358EJ UT WOS:000089544000007 ER PT J AU Asakawa, T Hara, K Mata, K Kadotani, T Kawamoto, H Kikuchi, T Kim, SH Kondo, K Kuwabara, T Okura, M Okutomi, H Sano, M Seiya, Y Shibayama, T Suzuki, T Takashima, S Takikawa, K Tanaka, M Tanaka, Y Uchida, T Watanabe, T AF Asakawa, T Hara, K Mata, K Kadotani, T Kawamoto, H Kikuchi, T Kim, SH Kondo, K Kuwabara, T Okura, M Okutomi, H Sano, M Seiya, Y Shibayama, T Suzuki, T Takashima, S Takikawa, K Tanaka, M Tanaka, Y Uchida, T Watanabe, T TI Cosmic-ray tests for quality control of the CDF plug upgrade EM calorimeter and the CDF plug preshower detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID TILE FIBER SYSTEM; MASS-PRODUCTION AB The CDF Plug Upgrade electromagnetic (EM) calorimeter and the preshower detector consist of tile-fiber elements forming a projective towel geometry. Each of the 23 longitudinal layers is separated into 24 units in the azimuthal direction. Cosmic-ray tests as a quality control of these mechanically basic units, called the 15 degrees units, were carried out since January 1995 and completed in June 1996. All the units amounting to a total 1200 units were processed. By using HAMAMASU R4125 for the photon readout, the average light yields were measured to be 5.8 and 21 photoelectrons for the EM and the preshower units, respectively. The light yield variation along the longitudinal layers of EM tower was measured to be 10%. A GEANT-simulation study using the results of the cosmic-ray tests was performed for a realistic calorimeter configuration. It was found that the simulated energy resolution was consistent with the requirement of Delta E/E = root(16%)(2)/E + (1%)(2) (E in GeV). Adding preshower response to EM response improved in particular the linearity of the calorimeter. It was possible to achieve the non-linearity of 1% level for energies in the range of 10-200 GeV. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tsukuba, Inst Phys, Tsukuba, Ibaraki 305, Japan. RP Seiya, Y (reprint author), Fermilab Natl Accelerator Lab, POB 500,MS-318, Batavia, IL 60510 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 21 PY 2000 VL 452 IS 1-2 BP 67 EP 80 DI 10.1016/S0168-9002(00)00352-1 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 358EJ UT WOS:000089544000009 ER PT J AU Vetter, K Kuhn, A Lee, IY Clark, RM Cromaz, M Deleplanque, MA Diamond, RM Fallon, P Lane, GJ Macchiavelli, AO Maier, MR Stephens, FS Svensson, CE Yaver, H AF Vetter, K Kuhn, A Lee, IY Clark, RM Cromaz, M Deleplanque, MA Diamond, RM Fallon, P Lane, GJ Macchiavelli, AO Maier, MR Stephens, FS Svensson, CE Yaver, H TI Performance of the GRETA prototype detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE HPGe detectors; position-sensitive detectors; GRETA; gamma-ray tracking ID PULSE-SHAPE ANALYSIS; GERMANIUM DETECTORS AB A working, two-dimensionally segmented Ge detector is one of the crucial elements in the development of GRETA - a next-generation 4 pi germanium detector array that uses three-dimensional positions and energies to of individual interactions of gamma rays in the detector to reconstruct the full energies and direction vectors of the individual gamma rays by employing tracking algorithms. The three-dimensional position and the energy of interactions will be determined by using a two-dimensionally, segmented Ge detector along with pulse-shape analysis of the signals. The current prototype is a 36-fold segmented HP-Ge detector in a closed-ended coaxial geometry. Preamplifiers with a compact design, low noise, and very good response properties have been built and implemented. An integrated noise level of about 5 keV has been measured for the segment channels. The average energy resolution of this detector was measured to be 1.14 and 1.93 keV at 60 and 1332 keV, respectively. Using pulse-shape analysis, a three-dimensional position sensitivity of 0.2 to 0.5 mm (R.M.S) has been obtained at 374 keV, dependent on the position and the direction. The results represent a major step towards the feasibility of a gamma-ray tracking detector. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Vetter, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Lane, Gregory/A-7570-2011 OI Lane, Gregory/0000-0003-2244-182X NR 15 TC 81 Z9 81 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 21 PY 2000 VL 452 IS 1-2 BP 105 EP 114 DI 10.1016/S0168-9002(00)00431-9 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 358EJ UT WOS:000089544000012 ER PT J AU Poon, AWP Komar, RJ Waltham, CE Browne, MC Robertson, RGH Kherani, NP Mak, HB AF Poon, AWP Komar, RJ Waltham, CE Browne, MC Robertson, RGH Kherani, NP Mak, HB TI A compact H-3(p,gamma)He-4 19.8-MeV gamma-ray source for energy calibration at the Sudbury Neutrino Observatory SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID THERMONUCLEAR REACTION-RATES AB The Sudbury Neutrino Observatory (SNO) is a new 1000-t D2O Cherenkov solar neutrino detector. A high-energy gamma-ray source is needed to calibrate SNO beyond the B-8 solar neutrino endpoint of 15 MeV. This paper describes the design and construction of a source that generates 19.8-MeV gamma rays using the H-3(p,gamma)He-4 reaction ("pT"), and demonstrates that the source meets all the physical, operational and lifetime requirements for calibrating SNO. An ion source was built into this unit to generate and to accelerate protons up to 30 keV, and a high-purity scandium tritide target with a scandium-tritium atomic ratio of 1:2.0 +/- 0.2 was included. This pT source is the first self-contained, compact, and portable high-energy gamma-ray source(E-gamma > 10 MeV). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci,Dept Phys & Astron, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Univ Washington, Phys Nucl Lab, Seattle, WA 98195 USA. Ontario Hydro Technol, Div Res, Toronto, ON M8Z 5S4, Canada. Queens Univ, Dept Phys, Kingston, ON K7L 3N6, Canada. RP Poon, AWP (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci,Dept Phys & Astron, Inst Nucl & Particle Astrophys, Mail Stop 50-208, Berkeley, CA 94720 USA. NR 31 TC 27 Z9 27 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 SEP 21 PY 2000 VL 452 IS 1-2 BP 115 EP 129 DI 10.1016/S0168-9002(00)00424-1 PG 15 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 358EJ UT WOS:000089544000013 ER PT J AU Amman, M Luke, PN AF Amman, M Luke, PN TI Three-dimensional position sensing and field shaping in orthogonal-strip germanium gamma-ray detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE gamma-ray imaging; gamma-ray spectroscopy; germanium detector; orthogonal strip; position sensing; field shaping ID BLOCKING CONTACTS; RESOLUTION; ENERGY AB We have fabricated a prototype orthogonal-strip germanium detector for gamma-ray imaging studies. With this detector we demonstrate that a gamma-ray interaction event in the detector can be located in three dimensions. In particular, we determine the interaction depth from the difference in time in the arrival of the holes at an electrode on one side of the detector and the arrival of the electrons at an electrode on the opposing detector surface. This depth of interaction sensing should lead to improved image resolution. A separate issue with such a detector is the loss of energy resolution and efficiency resulting from incomplete charge collection for interaction events taking place in the gap regions between the detector electrodes. We also demonstrate with our prototype detector that this problem can be substantially reduced by using field-shaping electrodes. A bias applied between the charge-sensing electrodes and the held-shaping electrodes improves the charge collection to the charge-sensing electrodes and consequently the detector performance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Amman, M (reprint author), Univ Calif Berkeley, Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 23 TC 83 Z9 83 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 21 PY 2000 VL 452 IS 1-2 BP 155 EP 166 DI 10.1016/S0168-9002(00)00351-X PG 12 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 358EJ UT WOS:000089544000017 ER PT J AU Vetter, K Kuhn, A Deleplanque, MA Lee, IY Stephens, FS Schmid, GJ Beckedahl, D Blair, JJ Clark, RM Cromaz, M Diamond, RM Fallon, P Lane, GJ Kammeraad, JE Macchiavelli, AO Svensson, CE AF Vetter, K Kuhn, A Deleplanque, MA Lee, IY Stephens, FS Schmid, GJ Beckedahl, D Blair, JJ Clark, RM Cromaz, M Diamond, RM Fallon, P Lane, GJ Kammeraad, JE Macchiavelli, AO Svensson, CE TI Three-dimensional position sensitivity in two-dimensionally segmented HP-Ge detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE HPGe detectors; position-sensitive detectors; GRETA; gamma-ray tracking ID PULSE-SHAPE ANALYSIS; GERMANIUM DETECTORS; GRETA AB Measured- and simulated-pulse shapes in electrically segmented coaxial Ge detectors have been investigated. Three-dimensional position sensitivities have been determined experimentally and theoretically in a 36-fold segmented Ge detector. By using the two-dimensional segmentation in conjunction with pulse-shape analysis, a position sensitivity of better than 1 mm can be obtained in three dimensions at an energy of 374 keV. This is achieved by analyzing the shape of net charge signals of segments containing interactions and of transient image charge signals of neighboring segments. The ability to locate interactions in three-dimensions is one of the crucial properties in the proposed gamma-ray energy tracking array (GRETA). The concept of gamma-ray tracking will not only increase the efficiency in detecting gamma radiation but also enables the localization and characterization of unknown gamma-ray sources with much higher accuracy than is possible with current instruments, (C) 2000 Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Bechtel Nevada, N Las Vegas, NV 89130 USA. RP Vetter, K (reprint author), Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Lane, Gregory/A-7570-2011 OI Lane, Gregory/0000-0003-2244-182X NR 18 TC 112 Z9 112 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD SEP 21 PY 2000 VL 452 IS 1-2 BP 223 EP 238 DI 10.1016/S0168-9002(00)00430-7 PG 16 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 358EJ UT WOS:000089544000024 ER PT J AU Morales, A Aalseth, CE Avignone, FT Brodzinski, RL Cebrian, S Garcia, E Gonzalez, D Hensley, WK Irastorza, IG Kirpichnikov, IV Klimenko, AA Miley, HS Morales, J de Solorzano, AO Osetrov, SB Pogosov, VS Puimedon, J Reeves, JH Sarsa, ML Scopel, S Smolnikov, AA Tamanyan, AG Vasenko, AA Vasiliev, SI Villar, JA AF Morales, A Aalseth, CE Avignone, FT Brodzinski, RL Cebrian, S Garcia, E Gonzalez, D Hensley, WK Irastorza, IG Kirpichnikov, IV Klimenko, AA Miley, HS Morales, J de Solorzano, AO Osetrov, SB Pogosov, VS Puimedon, J Reeves, JH Sarsa, ML Scopel, S Smolnikov, AA Tamanyan, AG Vasenko, AA Vasiliev, SI Villar, JA TI New constraints on WIMPS from the Canfranc IGEX dark matter search SO PHYSICS LETTERS B LA English DT Article ID LIMITS; CANDIDATES; DETECTORS AB The IGEX Collaboration enriched Ge-76 double-beta decay detectors are currently operating in the Canfranc Underground Laboratory with an overburden of 2450 m.w.e. A recent upgrade has made it possible to use them in a search for WIMPs. A new exclusion plot, sigma(m), has been derived for WIMP-nucleon spin-independent interaction. To obtain this result, 30 days of data from one IGEX detector, which has an energy threshold E-thr similar to 4 keV, have been considered. These data improve the exclusion limits derived from other ionization (non-thermal) germanium detector experiments in the similar to 50 GeV DAMA region, and show that with a moderate improvement of the background below 10 keV, the DAMA region may be tested with an additional 1 kg-year of exposure. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Zaragoza, Lab Nucl & High Energy Phys, E-50009 Zaragoza, Spain. Univ S Carolina, Columbia, SC 29208 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Inst Theoret & Expt Phys, Moscow 117259, Russia. Baksan Neutrino Observ, Inst Nucl Res, Neutrino 361609, Russia. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Univ Zaragoza, Lab Nucl & High Energy Phys, E-50009 Zaragoza, Spain. RI Irastorza, Igor/B-2085-2012; Sarsa Sarsa, Maria Luisa/K-6108-2014; Villar, Jose Angel/K-6630-2014; OI Irastorza, Igor/0000-0003-1163-1687; Sarsa Sarsa, Maria Luisa/0000-0002-7552-1228; Villar, Jose Angel/0000-0003-0228-7589; Garcia Abancens, Eduardo/0000-0002-9827-2332 NR 20 TC 40 Z9 40 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD SEP 21 PY 2000 VL 489 IS 3-4 BP 268 EP 272 DI 10.1016/S0370-2693(00)00956-4 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 358HD UT WOS:000089551800002 ER PT J AU Wang, FQ AF Wang, FQ TI Correlation between the charged kaon ratio and the baryon phase-space density in heavy-ion collisions SO PHYSICS LETTERS B LA English DT Article ID NUCLEUS-NUCLEUS COLLISIONS; PARTICLE RATIOS; PROTON-NUCLEUS; BEAM ENERGIES; DISTRIBUTIONS; MIDRAPIDITY; MODEL; AGS AB It is found that the average baryon phase-space density obtained from the ratio of deuteron to proton yields is nearly constant over centrality in Au + Au collisions at the AGS. The finding offers an explanation for the puzzling centrality independence of the ratio of charged kaon total yields. The correlation between the charged kaon ratio and the average baryon phase-space density is studied for central heavy-ion collisions of various systems over a wide range of beam energy. It is found that the charged kaon ratio and the average baryon phase-space density both increase with decreasing beam energy, and are strongly correlated. Such study may provide a new approach to search for medium effects on the kaon mass. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Wang, FQ (reprint author), Purdue Univ, Dept Phys, 1396 Phys Bldg, W Lafayette, IN 47907 USA. NR 31 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD SEP 21 PY 2000 VL 489 IS 3-4 BP 273 EP 279 DI 10.1016/S0370-2693(00)00975-8 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 358HD UT WOS:000089551800003 ER PT J AU Binetruy, P Cline, JM Grojean, C AF Binetruy, P Cline, JM Grojean, C TI Dynamical instability of brane solutions with a self-tuning cosmological constant SO PHYSICS LETTERS B LA English DT Article ID DIMENSIONS; TEV; UNIFICATION; MILLIMETER AB A five-dimensional solution to Einstein's equations coupled to a scalar field has been proposed as a partial solution to the cosmological constant problem: the effect of arbitrary vacuum energy (tension) of a 3-brane is cancelled; however, the scalar field becomes singular at some finite proper distance in the extra dimension. We show that in the original model with a vanishing bulk potential for the scalar, the solution is a saddle point which is unstable to expansion or contraction of the brane world. We construct exact time-dependent solutions which generalize the static solution, and demonstrate that they do not conserve energy on the brane; thus they do not have an effective 4-D field theoretic description. When a bulk scalar field potential is added, the boundary conditions on the brane cannot be trivially satisfied, raising hope that the self-tuning mechanism may still give some insight into the cosmological constant problem in this case. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Paris 11, LPT, UMR 8627, F-91405 Orsay, France. McGill Univ, Dept Phys, Montreal, PQ H3A 2T8, Canada. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Binetruy, P (reprint author), Univ Paris 11, LPT, UMR 8627, Batiment 211, F-91405 Orsay, France. OI grojean, christophe/0000-0002-7196-7361 NR 47 TC 58 Z9 58 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 SEP 21 PY 2000 VL 489 IS 3-4 BP 403 EP 410 DI 10.1016/S0370-2693(00)00932-1 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 358HD UT WOS:000089551800021 ER PT J AU Alcock, C Allsman, RA Alves, D Axelrod, TS Baines, D Becker, AC Bennett, DP Bourke, A Brakel, A Cook, KH Crook, B Crouch, A Dan, J Drake, AJ Fragile, PC Freeman, KC Gal-Yam, A Geha, M Gray, J Griest, K Gurtierrez, A Heller, A Howard, J Johnson, BR Kaspi, S Keane, M Kovo, O Leach, C Leach, T Leibowitz, EM Lehner, MJ Lipkin, Y Maoz, D Marshall, L McDowell, D McKeown, S Mendelson, H Messenger, B Minniti, D Nelson, C Peterson, BA Popowski, P Pozza, E Purcell, P Pratt, MR Quinn, J Quinn, PJ Rhie, SH Rodgers, AW Salmon, A Shemmer, O Stetson, P Stubbs, CW Sutherland, W Thomson, S Tomaney, A Vandehei, T Walker, A Ward, K Wyper, G AF Alcock, C Allsman, RA Alves, D Axelrod, TS Baines, D Becker, AC Bennett, DP Bourke, A Brakel, A Cook, KH Crook, B Crouch, A Dan, J Drake, AJ Fragile, PC Freeman, KC Gal-Yam, A Geha, M Gray, J Griest, K Gurtierrez, A Heller, A Howard, J Johnson, BR Kaspi, S Keane, M Kovo, O Leach, C Leach, T Leibowitz, EM Lehner, MJ Lipkin, Y Maoz, D Marshall, L McDowell, D McKeown, S Mendelson, H Messenger, B Minniti, D Nelson, C Peterson, BA Popowski, P Pozza, E Purcell, P Pratt, MR Quinn, J Quinn, PJ Rhie, SH Rodgers, AW Salmon, A Shemmer, O Stetson, P Stubbs, CW Sutherland, W Thomson, S Tomaney, A Vandehei, T Walker, A Ward, K Wyper, G CA MACHO GMAN Collaboration TI Binary microlensing events from the MACHO Project SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; dark matter; gravitational lensing; stars : low-mass; brown dwarfs ID LARGE-MAGELLANIC-CLOUD; GRAVITATIONAL LENSING EXPERIMENT; RR-LYRAE STARS; RED CLUMP STARS; GALACTIC BULGE; PLANETARY SYSTEMS; BAADES WINDOW; HALO; PHOTOMETRY; EXTINCTION AB We present the light curves of 21 gravitational microlensing events from the first six years of the MACHO Project gravitational microlensing survey that are likely examples of lensing by binary systems. These events were manually selected from a total sample of similar to 350 candidate microlensing events that were either detected by the MACHO Alert System or discovered through retrospective analyses of the MACHO database. At least 14 of these 21 events exhibit strong (caustic) features, and four of the events are well fit with lensing by large mass ratio (brown dwarf or planetary) systems, although these fits are not necessarily unique. The total binary event rate is roughly consistent with predictions based upon our knowledge of the properties of binary stars, but a precise comparison cannot be made without a determination of our binary lens event detection efficiency. Toward the Galactic bulge, we find a ratio of caustic crossing to noncaustic crossing binary lensing events of 12:4, excluding one event for which we present two fits. This suggests significant incompleteness in our ability to detect and characterize noncaustic crossing binary lensing. The distribution of mass ratios, N(q), for these binary lenses appears relatively flat. We are also able to reliably measure source-face crossing times in four of the bulge caustic crossing events, and recover from them a distribution of lens proper motions, masses, and distances consistent with a population of Galactic bulge lenses at a distance of 7 +/- 1 kpc. This analysis yields two systems with companions of similar to 0.05 M.. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Australian Natl Univ, Supercomp Facil, Canberra, ACT 0200, Australia. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Canberra Astron Soc, Reynolds Amateur Photometry Team, Canberra, ACT 0200, Australia. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Monash Univ, Dept Math & Stat, Clayton, Vic 3168, Australia. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. Univ Calif San Diego, Dept Phys, San Diego, CA 92093 USA. Univ Calif Davis, Dept Phys, Davis, CA 92093 USA. Univ Minnesota, Tate Lab Phys, Minneapolis, MN 55455 USA. Univ Sheffield, Dept Phys, Sheffield S3 7RH, S Yorkshire, England. Pontificia Univ Catolica Chile, Dept Astron, Santiago 22, Chile. Univ Calif Berkeley, Dept Phys, Berkeley, CA 92093 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. European So Observ, D-85748 Garching, Germany. Natl Res Council Canada, Victoria, BC V8X 4M6, Canada. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. RP Alcock, C (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI Stubbs, Christopher/C-2829-2012; Quinn, Peter/B-3638-2013; OI Stubbs, Christopher/0000-0003-0347-1724; Lehner, Matthew/0000-0003-4077-0985 NR 97 TC 96 Z9 96 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 2000 VL 541 IS 1 BP 270 EP 297 DI 10.1086/309393 PN 1 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360YE UT WOS:000089694300028 ER PT J AU Choe, GS Cheng, CZ AF Choe, GS Cheng, CZ TI A model of solar flares and their homologous behavior SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; methods : numerical; Sun : flares; Sun : magnetic fields ID CORONAL MASS EJECTIONS; FREE MAGNETIC-FIELDS; FOOTPOINT SHEARING; PLASMA EJECTION; EVOLUTION; RECONNECTION; PROMINENCES; ARCADES; ENERGY; ATMOSPHERE AB A model describing physical processes of solar flares and their homologous behavior is presented based on resistive MHD simulations of magnetic arcade evolution subject to continuous shear-increasing footpoint motions. It is proposed in our model that the individual flaring process encompasses magnetic reconnection of arcade field lines, generation of magnetic islands in the magnetic arcade, and coalescence of magnetic islands. When a magnetic arcade is sheared, a current sheet is formed and magnetic reconnection can take place to form a magnetic island. A continuing increase of magnetic shear can trigger a new reconnection process and create another island in the underlying arcade below the original magnetic island. The newborn island rises faster than the preceding island and merges with it to form one island. Before completing the merging process, the newborn island exhibits two different phases of rising motion: the first phase with a slower rising speed and the second phase with a faster rising speed. This is consistent with the Yohkoh observation by Ohyama & Shibata (1998) of X-ray plasma ejecta motion. The first phase, in which reconnection of line-tied held in the underlying arcade is important, can be regarded as being related with the preflare phase. In the second phase, the island coalescence takes place, which creates an elongated current sheet below and enhances the reconnection rate of the line-tied arcade field. This phase is interpreted as the impulsive phase or the flash phase of flares. The obtained reconnection electric field is large enough to accelerate electrons to an energy level higher than 10 keV, which is necessary for observed X-ray emissions. After merging of the islands is completed, magnetic reconnection continues in the current sheet under the integrated island for rather a long period, which can be considered as the main phase of hares. The sequence of all these processes is repeated with some time interval while a shear-increasing motion continues. We propose that a series of these flaring processes constitutes a set of homologous hares. The time interval between successive flaring events depends on the energy input rate into the system, which is governed by the nature of the footpoint motion and the flux reconnecting rate. We also have investigated the destruction of a magnetic island in a system undergoing a decrease of magnetic shear. The result suggests that there is a critical value of magnetic shear for existence of a magnetic island in an arcade-like held configuration. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Choe, GS (reprint author), Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. EM gchoe@pppl.gov; fcheng@pppl.gov RI Choe, Gwangson/E-2366-2013; Cheng, Chio/K-1005-2014 NR 71 TC 34 Z9 34 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 2000 VL 541 IS 1 BP 449 EP 467 DI 10.1086/309415 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360YE UT WOS:000089694300046 ER PT J AU Trabert, E Beiersdorfer, P Utter, SB Brown, GV Chen, H Harris, CL Neill, PA Savin, DW Smith, AJ AF Trabert, E Beiersdorfer, P Utter, SB Brown, GV Chen, H Harris, CL Neill, PA Savin, DW Smith, AJ TI Experimental M1 transition rates of coronal lines from Ar x, Ar xiv, and Ar xv SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; methods : laboratory ID BERYLLIUM ISOELECTRONIC SEQUENCE; BEAM ION-TRAP; MAGNETIC DIPOLE TRANSITIONS; DIRAC-FOCK CALCULATION; ATOMIC DATA; MEASURED LIFETIMES; METASTABLE LEVELS; CONFIGURATIONS; INTENSITIES; PRECISION AB Transition probabilities of three magnetic dipole (M1) transitions in multiply charged ions of Ar have been measured using the Livermore electron-beam ion trap. Two of the transitions are in the ground configurations of Ar XIV (B-like) and Ar nr (F-like), and are associated with the coronal lines at 4412.4 and 5533.4 Angstrom, respectively. The third is in the excited 2s2p configuration of Be-like Ar XV and produces the coronal line at 5943.73 Angstrom. Our results for the three atomic level lifetimes are 9.32 +/- 0.12 ms for the Ar x 2s(2)2p(5) P-2(1/2)o level, 9.70 +/- 0.15 ms for the Ar XIV 2s(2)2p P-2(3/2)o level, and 15.0 +/- 0.8 ms for the Ar XV 2s2p (3)p(2)(o), level. These results differ significantly from earlier measurements and are the most accurate ones to date. C1 Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94551 USA. Ruhr Univ Bochum, Fak Phys & Astron, D-44780 Bochum, Germany. Univ Nevada, Dept Phys, Reno, NV 89557 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Morehouse Coll, Dept Phys, Atlanta, GA 30314 USA. RP Trabert, E (reprint author), Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94551 USA. RI Savin, Daniel/B-9576-2012 OI Savin, Daniel/0000-0002-1111-6610 NR 43 TC 55 Z9 55 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 2000 VL 541 IS 1 BP 506 EP 511 DI 10.1086/309427 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360YE UT WOS:000089694300051 ER PT J AU Ryutova, MP Tarbell, TD AF Ryutova, MP Tarbell, TD TI On the transition region explosive events SO ASTROPHYSICAL JOURNAL LA English DT Article DE instabilities; shock waves; Sun : chromosphere; Sun : transition region ID SUN AB We describe the properties of high-velocity and explosive events in the solar transition region determined from time series of data taken by the Transition Region and Coronal Explorer and the SUMER instrument on the Solar and Heliospheric Observatory (SOHO) simultaneously in several chromospheric and transition region lines co-aligned with high-resolution Michelson Doppler Imager (SOHO) magnetograms. We outline what the various features of these events can tell us about the heating mechanisms and formation of plasma flows. Our results strongly support the mechanism of hydrodynamic cumulation of energy associated with the cascade of shock waves produced by colliding and reconnecting flux tubes in the photospheric network (as recently discussed by T. D. Tarbell et al.), We find that the majority of the explosive events are caused by the explosive instability occurring in the presence of the behind-shock downflows, and less than 10% can be explained by the direct collision of shuck fronts. C1 Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Sci, Livermore, CA 94551 USA. RP Ryutova, MP (reprint author), Lockheed Martin Adv Technol Ctr, 3251 Hanover St, Palo Alto, CA 94304 USA. NR 14 TC 24 Z9 25 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 2000 VL 541 IS 1 BP L29 EP L32 DI 10.1086/312891 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360YH UT WOS:000089694600008 ER PT J AU Ustyugova, GV Lovelace, RVE Romanova, MM Li, H Colgate, SA AF Ustyugova, GV Lovelace, RVE Romanova, MM Li, H Colgate, SA TI Poynting jets from accretion disks: Magnetohydrodynamic simulations SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; magnetic fields; MHD; plasmas ID DOUBLE RADIO-SOURCES; GAMMA-RAY FLARES; MAGNETIC-FIELD; OUTFLOWS; FLOWS; OUTBURSTS; MODEL AB The powerful narrow jets observed to emanate from many compact accreting objects may arise from the twisting of a magnetic field threading a differentially rotating accretion disk that acts to extract magnetically the angular momentum and energy from the disk. Two main regimes have been discussed, hydromagnetic outflows, which have a significant mass flux and which have the energy and angular momentum carried by both the matter and the electromagnetic field, and Poynting outflows, in which the mass flux is negligible and the energy and angular momentum are carried predominantly by the electromagnetic field. Recent simulation studies have focused almost exclusively on hydromagnetic outflows. Here we consider a Keplerian disk initially threaded by a dipole like poloidal magnetic field. We present the first MHD simulation results establishing that a quasi-stationary collimated Poynting jet arises from the inner part of the disk while a steady uncollimated hydromagnetic outflow arises in the outer part of the disk. C1 Russian Acad Sci, Keldysh Inst Appl Math, Moscow 125047, Russia. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Ustyugova, GV (reprint author), Russian Acad Sci, Keldysh Inst Appl Math, Moscow 125047, Russia. EM rvl1@cornell.edu NR 35 TC 82 Z9 82 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 20 PY 2000 VL 541 IS 1 BP L21 EP L24 DI 10.1086/312890 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360YH UT WOS:000089694600006 ER PT J AU Martin, DF Colella, P AF Martin, DF Colella, P TI A cell-centered adaptive projection method for the incompressible Euler equations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE adaptive mesh refinement; incompressible flow; projection methods ID NAVIER-STOKES EQUATIONS; MESH REFINEMENT; FLOW AB We present an algorithm to compute adaptive solutions for incompressible flows using block-structured local refinement in both space and time. This method uses a projection formulation based on a cell-centered approximate projection. which allows the use of a single set of cell-centered solvers. Because of refinement in time, additional steps are taken to accurately discretize the advection and projection operators at grid refinement boundaries using composite operators which span the coarse and refined grids. This ensures that the method is approximately freestream preserving and satisfies an appropriate form of the divergence constraint. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Appl Numer Algorithms Grp, Berkeley, CA 94720 USA. RP Martin, DF (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Appl Numer Algorithms Grp, Berkeley, CA 94720 USA. NR 36 TC 54 Z9 57 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 SEP 20 PY 2000 VL 163 IS 2 BP 271 EP 312 DI 10.1006/jcph.2000.6575 PG 42 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 361NP UT WOS:000089729400001 ER PT J AU Qiang, J Ryne, RD Habib, S Decyk V AF Qiang, J Ryne, RD Habib, S Decyk, V TI An object-oriented parallel particle-in-cell code for beam dynamics simulation in linear accelerators SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE object-oriented; particle-in-cell; beam dynamics; linear accelerators ID MODEL; INTEGRATION AB We present an object-oriented three-dimensional parallel particle-in-cell (PIC) code for simulation of beam dynamics in linear accelerators (linacs), An important feature of this code is the use of split-operator methods to integrate single-particle magnetic optics techniques with parallel PIC techniques. By choosing a splitting scheme that separates the self-fields from the complicated externally applied fields, we are able to utilize a large step size and still retain high accuracy. The method employed is symplectic and can be generalized to arbitrarily high order accuracy if desired. A two-dimensional parallel domain decomposition approach is employed within a message-passing programming paradigm along with a dynamic load balancing scheme. Performance tests on an SGI/Cray T3E-900 and an SGI Origin 2000 show good scalability of the object-oriented code. We present, as an example, a simulation of high current beam transport in the accelerator production of tritium (APT) linac design. (C) 2000 Academic Press. C1 Los Alamos Natl Lab, LANSCE 1, Los Alamos, NM 87545 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90024 USA. RP Qiang, J (reprint author), Los Alamos Natl Lab, LANSCE 1, Ms H817, Los Alamos, NM 87545 USA. EM jiqiang@lanl.gov; ryne@lanl.gov; habib@lanl.gov; vdecyk@pepper.physics.ucla.edu NR 38 TC 109 Z9 109 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE 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 SEP 20 PY 2000 VL 163 IS 2 BP 434 EP 451 DI 10.1006/jcph.2000.6570 PG 18 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 361NP UT WOS:000089729400006 ER PT J AU Sethian, JA Wiegmann, A AF Sethian, JA Wiegmann, A TI Structural boundary design via level set and immersed interface methods SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE self design of elastic structures; level set method; explicit jump immersed interface method; immersed interface method; linear elastostatics ID NONSYMMETRIC LINEAR-SYSTEMS; CURVATURE; EQUATION; FRONTS AB We develop and test an algorithmic approach to the boundary design of elastic structures. The goal of our approach is two-fold: first, to develop a method which allows one to rapidly solve the two-dimensional Lame equations in arbitrary domains and compute, for example, the stresses, and second, to develop a systematic way of modifying the design to optimize chosen properties. At the core, our approach relies on two distinct steps. Given a design, we first apply an explicit jump immersed interface method to compute the stresses for a given design shape. We then use a narrow band level set method to perturb this shape and progress towards an improved design. The equations of 2D linear elastostatics in the displacement formulation on arbitrary domains are solved quickly by domain embedding and the use of fast elastostatic solvers. This effectively reduces the dimensionality of the problem by one. Once the stresses are found, the level set method, which represents the design structure through an embedded implicit function, is used in the second step to alter the shape, with velocities depending on the stresses in the current design, Criteria are provided for advancing the shape in an appropriate direction and fur correcting the evolving shape when given constraints are violated. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sethian, JA (reprint author), Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. RI UF, MDO/G-8720-2012 NR 38 TC 415 Z9 458 U1 3 U2 43 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 SEP 20 PY 2000 VL 163 IS 2 BP 489 EP 528 DI 10.1006/jcph.2000.6581 PG 40 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 361NP UT WOS:000089729400009 ER PT J AU Hughes, TA Kevan, SD Cox, DE Johnson, DC AF Hughes, TA Kevan, SD Cox, DE Johnson, DC TI Synthesis of superlattices of intercalated transition metal dichalcogenides SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GIANT MAGNETORESISTANCE; TANTALUM DICHALCOGENIDES; MODULATED REACTANTS; MAGNETIC-PROPERTIES; NIOBIUM AB Thin films of oriented Fe and Cr intercalated (NbSe2)(x)(TiSe2)(y) superlattices have been synthesized by controlled annealing of elementally modulated reactants. Analytic techniques have been developed to extract the average c-axis structure of the unit cell, the distribution of c-axis crystal sizes, and the distribution of structural defects from X-ray diffraction data. High-resolution synchrotron source X-ray diffraction data were collected from a [(Fe0.33NbSe2)(8)(Fe0.33TiSe2)(8)](12) Sample (i.e., 12 superlattice unit cells in the film, each cell containing 8 layers of Fe0.33NbSe2 followed by 8 layers of Fe0.33TiSe2) at three anomalously scattering wavelengths. Analysis determined structural parameters within 2% of published values fur the parent compounds, typical crystal sizes of 200-500 Angstrom, and typical coherence losses over a unit cell of +/-1%. Theoretical diffraction profiles calculated directly from the model structure are shown to agree satisfactorily with experiment. The flexibility offered by our growth technique suggests that synthesis of many such superlattices with a variety of different materials properties should be possible. C1 Univ Oregon, Dept Chem, Eugene, OR 97403 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Johnson, DC (reprint author), Univ Oregon, Dept Chem, Eugene, OR 97403 USA. RI Kevan, Stephen/F-6415-2010 OI Kevan, Stephen/0000-0002-4621-9142 NR 21 TC 6 Z9 6 U1 7 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD SEP 20 PY 2000 VL 122 IS 37 BP 8910 EP 8915 DI 10.1021/ja994140o PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 356QK UT WOS:000089453800013 ER PT J AU Wu, KS Simon, H AF Wu, KS Simon, H TI Thick-restart Lanczos method for large symmetric eigenvalue problems SO SIAM JOURNAL ON MATRIX ANALYSIS AND APPLICATIONS LA English DT Article DE thick-restart; Lanczos eigenvalue method; partial reorthogonalization ID ARNOLDI METHOD; REORTHOGONALIZATION; ITERATION; ALGORITHM; DAVIDSON AB In this paper, we propose a restarted variant of the Lanczos method for symmetric eigenvalue problems named the thick-restart Lanczos method. This new variant is able to retain an arbitrary number of Ritz vectors from the previous iterations with a minimal restarting cost. Since it restarts with Ritz vectors, it is simpler than similar methods, such as the implicitly restarted Lanczos method. We carefully examine the effects of the floating-point round-off errors on stability of the new algorithm and present an implementation of the partial reorthogonalization scheme that guarantees accurate Ritz values with a minimal amount of reorthogonalization. We also show a number of heuristics on deciding which Ritz pairs to save during restart in order to maximize the overall performance of the thick-restart Lanczos method. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Wu, KS (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. NR 29 TC 109 Z9 115 U1 0 U2 4 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0895-4798 J9 SIAM J MATRIX ANAL A JI SIAM J. Matrix Anal. Appl. PD SEP 20 PY 2000 VL 22 IS 2 BP 602 EP 616 DI 10.1137/S0895479898334605 PG 15 WC Mathematics, Applied SC Mathematics GA 367BF UT WOS:000090041100019 ER PT J AU Chen, DA Bartelt, MC Seutter, SM McCarty, KF AF Chen, DA Bartelt, MC Seutter, SM McCarty, KF TI Small, uniform, and thermally stable silver particles on TiO2(110)-(1x1) SO SURFACE SCIENCE LA English DT Article DE metallic films; nucleation; scanning tunneling microscopy; silver; titanium oxide ID SURFACES; METALS AB We have investigated the growth of silver islands on TiO2 (110)-(1 x 1) by scanning tunneling microscopy (STM). For room-temperature deposition of coverages between 0.05 and 1.0 ML, small, three-dimensional islands with a narrow diameter distribution are formed. The observed behavior is qualitatively similar to the 'self-limiting' growth previously reported for Cu on the (110) surface of titania (rutile). That is, above about 0.5 ML, the average Ag island diameter is nearly independent of coverage and island nucleation continues up to 1 ML in coverage. However, at the same coverage, the density of Ag islands is roughly half that of Cu islands and the Ag islands are larger, differences resulting from the higher mobility of Ag compared with Cu. The Ag islands are remarkably stable under thermal annealing - long-term or high-temperature annealing increases the island diameter by less than a factor of two. Strikingly, the island densities for annealed adlayers are nearly independent of coverage above 0.25 ML. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Livermore, CA 94550 USA. RP Sandia Natl Labs, Livermore, CA 94550 USA. EM mccarty@sandia.gov RI McCarty, Kevin/F-9368-2012; OI McCarty, Kevin/0000-0002-8601-079X; Chen, Donna A./0000-0003-4962-5530 NR 13 TC 52 Z9 53 U1 0 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 EI 1879-2758 J9 SURF SCI JI Surf. Sci. PD SEP 20 PY 2000 VL 464 IS 1 BP L708 EP L714 DI 10.1016/S0039-6028(00)00700-7 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 359JU UT WOS:000089608400008 ER PT J AU Zollino, M Di Stefano, C Zampino, G Mastroiacovo, P Wright, TJ Sorge, G Selicorni, A Tenconi, R Zappala, A Battaglia, A Di Rocco, M Palka, G Pallotta, R Altherr, MR Neri, G AF Zollino, M Di Stefano, C Zampino, G Mastroiacovo, P Wright, TJ Sorge, G Selicorni, A Tenconi, R Zappala, A Battaglia, A Di Rocco, M Palka, G Pallotta, R Altherr, MR Neri, G TI Genotype-phenotype correlations and clinical diagnostic criteria in Wolf-Hirschhorn syndrome SO AMERICAN JOURNAL OF MEDICAL GENETICS LA English DT Article DE microdeletion; nondeleted patient; Wolf-Hirschhorn syndrome ID SYNDROME CRITICAL REGION; ROGERS-DANKS-SYNDROME; INSITU HYBRIDIZATION; DELETION; GENE; MAP; CONFIRMATION; 4P16; FISH AB We report on a clinical-genetic study of 16 Wolf-Hirschhorn syndrome (WHS) patients. Hemizygosity of 4p16.3 was detected by conventional prometaphase chromosome analysis (11 patients) or by molecular probes on apparently normal chromosomes (4 patients), One patient had normal chromosomes without a detectable molecular deletion within the WHS "critical region." In each deleted patient, the deletion was demonstrated to be terminal by fluorescence in situ hybridization (FISH), The proximal breakpoint of the rearrangement was established by prometaphase chromosome analysis in cases with a visible deletion. It was within the 4p16.1 band in six patients, apparently coincident with the distal half of this band in five patients. The extent of each of the four submicroscopic deletions was established by FISH analyses with a set of overlapping cosmid clones spanning the 4p16.3 region. We found ample variations in both the size of the deletions and the position of the respective breakpoints, The precise definition of the cytogenetic defect permitted an analysis of the genotype-phenotype correlations in WHS, leading to the proposal of a set of minimal diagnostic criteria, which in turn may facilitate the selection of critical patients in the search for the gene(s) responsible for this disorder. We observed that genotype-phenotype correlations in WHS mostly depend on the size of the deletion, a deletion of <3.5 Mb resulting in a mild phenotype, in which malformations are absent, The absence of a detectable molecular deletion is still consistent with a WHS diagnosis. Based on these observations a "minimal" WHS phenotype was inferred, the clinical manifestations of which are restricted to the typical facial appearance, mild mental and growth retardation, and congenital hypotonia, (C) 2000 Wiley-Liss, Inc. C1 Univ Cattolica Sacro Cuore, Ist Genet Med, Fac Med A Gemelli, I-00168 Rome, Italy. UCSC, Fac Med A Gemelli, Ist Pediat, Rome, Italy. Los Alamos Natl Lab, Div Life Sci, Genom Grp, Los Alamos, NM USA. Univ Catania, Pediat Clin, I-95124 Catania, Italy. Univ Milan, Clin Pediat G&D De Marchi, Milan, Italy. Univ Padua, Dipartimento Pediat, I-35128 Padua, Italy. Univ Pisa, Ist Neuropsichiatria Infantile Stella Maris, Calambrone, Italy. Ist Giannina Gaslini, Div Pediat, I-16148 Genoa, Italy. Univ G dAnnunzio, Ist Pediat & Genet, Chieti, Italy. IRCCS Z Medea Assoc Nostra Faiglia, Parini, Lecco, Italy. RP Zollino, M (reprint author), Univ Cattolica Sacro Cuore, Ist Genet Med, Fac Med A Gemelli, Largo F Vito 1, I-00168 Rome, Italy. EM mzollino@rm.unicatt.it NR 19 TC 109 Z9 112 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0148-7299 J9 AM J MED GENET JI Am. J. Med. Genet. PD SEP 18 PY 2000 VL 94 IS 3 BP 254 EP 261 DI 10.1002/1096-8628(20000918)94:3<254::AID-AJMG13>3.0.CO;2-7 PG 8 WC Genetics & Heredity SC Genetics & Heredity GA 349AZ UT WOS:000089022800013 PM 10995514 ER PT J AU Francoeur, S Zhang, Y Norman, AG Alsina, F Mascarenhas, A Reno, JL Jones, ED Lee, SR Follstaedt, DM AF Francoeur, S Zhang, Y Norman, AG Alsina, F Mascarenhas, A Reno, JL Jones, ED Lee, SR Follstaedt, DM TI Optical properties of spontaneous lateral composition modulation in AlAs/InAs short-period superlattices SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; LAYER ORDERING PROCESS; SEMICONDUCTOR ALLOYS AB The effect of lateral composition modulation, spontaneously generated during the epitaxial growth of an AlAs/InAs short-period superlattice, on the electronic band structure is investigated using phototransmission and photoluminescence spectroscopy. Compared with uniform layers of identical average composition, the presence of the composition modulation considerably reduces the band-gap energy and produces strongly polarized emission and absorption spectra. We demonstrate that the dominant polarization direction can selectively be aligned along the [(1) over bar 10] or [010] crystallographic directions. In compressively strained samples, the use of (001) InP substrates slightly miscut toward (111)A or (101) resulted in modulation directions along [110] or [100], respectively, and dominant polarization directions along a direction orthogonal to the respective composition modulation. Band-gap reductions as high as 350 and 310 meV are obtained for samples with composition modulation along [110] and [100], respectively. Ratios of polarized intensities up to 26 are observed in transmission spectra. (C) 2000 American Institute of Physics. [S0003-6951(00)03438-0]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Francoeur, S (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Alzina, Francesc/C-5468-2008; Norman, Andrew/F-1859-2010; Francoeur, Sebastien/E-6614-2011 OI Alzina, Francesc/0000-0002-7082-0624; Norman, Andrew/0000-0001-6368-521X; Francoeur, Sebastien/0000-0002-6129-7026 NR 13 TC 10 Z9 10 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 18 PY 2000 VL 77 IS 12 BP 1765 EP 1767 DI 10.1063/1.1311598 PG 3 WC Physics, Applied SC Physics GA 352VR UT WOS:000089239000009 ER PT J AU Stach, EA Kelsch, M Nelson, EC Wong, WS Sands, T Cheung, NW AF Stach, EA Kelsch, M Nelson, EC Wong, WS Sands, T Cheung, NW TI Structural and chemical characterization of free-standing GaN films separated from sapphire substrates by laser lift-off SO APPLIED PHYSICS LETTERS LA English DT Article AB Laser lift-off of GaN heteroepitaxial layers from sapphire substrates is a promising method for electronic device integration and GaN substrate creation. Of critical importance is the structural and chemical quality of the GaN layers following laser processing. In this letter, transmission electron microscopy techniques are used to characterize the modifications that occur at the resulting GaN surfaces. Structural alteration and chemical intermixing following lift-off are confined to approximately the first 50 nm. These results indicate that laser lift-off is a viable route for GaN substrate creation, as well as for electronic device integration. (C) 2000 American Institute of Physics. [S0003-6951(00)03337-4]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat & Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Elect Engn, Berkeley, CA 94720 USA. RP Stach, EA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. RI Sands, Timothy/D-2133-2009; Stach, Eric/D-8545-2011 OI Sands, Timothy/0000-0001-9718-6515; Stach, Eric/0000-0002-3366-2153 NR 8 TC 46 Z9 46 U1 0 U2 8 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 SEP 18 PY 2000 VL 77 IS 12 BP 1819 EP 1821 DI 10.1063/1.1309030 PG 3 WC Physics, Applied SC Physics GA 352VR UT WOS:000089239000027 ER PT J AU Lenosky, TJ Sadigh, B Theiss, SK Caturla, MJ de la Rubia, TD AF Lenosky, TJ Sadigh, B Theiss, SK Caturla, MJ de la Rubia, TD TI Ab initio energetics of boron-interstitial clusters in crystalline Si SO APPLIED PHYSICS LETTERS LA English DT Article ID TOTAL-ENERGY CALCULATIONS; WAVE BASIS-SET; TIGHT-BINDING; C-SI; DIFFUSION; SILICON; PSEUDOPOTENTIALS; TENDENCY; DEFECTS; METALS AB We have performed an extensive first-principles study of the energetics of boron clustering in silicon in the presence of excess self-interstitial atoms (SIAs). We consider complexes with up to four B atoms and two SIAs. We have conducted an extensive search for the ground-state configurations and charge states of these clusters. We find the cluster containing three B atoms and one SIA(B3I) to be remarkably stable, while all our clusters with more than 80% boron content are unstable. Hence, we propose B3I to be a stable nucleus that can grow to larger clusters. The energetics presented here can be used as input to large-scale predictive models for B diffusion and activation during ion implantation and thermal annealing. (C) 2000 American Institute of Physics. [S0003-6951(00)00538-6]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Lenosky, TJ (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RI Caturla, Maria /D-6241-2012 OI Caturla, Maria /0000-0002-4809-6553 NR 15 TC 63 Z9 64 U1 0 U2 5 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 SEP 18 PY 2000 VL 77 IS 12 BP 1834 EP 1836 DI 10.1063/1.1310627 PG 3 WC Physics, Applied SC Physics GA 352VR UT WOS:000089239000032 ER PT J AU Mancoff, FB Dunn, JH Clemens, BM White, RL AF Mancoff, FB Dunn, JH Clemens, BM White, RL TI A giant magnetoresistance sensor for high magnetic field measurements SO APPLIED PHYSICS LETTERS LA English DT Article ID MULTILAYERS; FILMS; SUPERLATTICES; ANISOTROPIES; TEMPERATURES AB We used giant magnetoresistance in a magnetic field sensor able to measure large fields of up to several kG. We deposit spin valves with a magnetic multilayer with perpendicular anisotropy as one ferromagnet and a material with in-plane anisotropy as the other ferromagnet. For magnetic fields along the film normal, the multilayer's magnetization is fixed perpendicular while the magnetic layer with in-plane anisotropy is rotated towards out-of-plane magnetization. The device response is nearly linear with applied field and determines both the magnitude and sign of the field, making it attractive for measuring large magnetic fields. (C) 2000 American Institute of Physics. [S0003-6951(00)02138-0]. C1 Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. RP Mancoff, FB (reprint author), Stanford Univ, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. NR 12 TC 44 Z9 46 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 SEP 18 PY 2000 VL 77 IS 12 BP 1879 EP 1881 DI 10.1063/1.1311316 PG 3 WC Physics, Applied SC Physics GA 352VR UT WOS:000089239000047 ER PT J AU Gerken, M Dixon, DA Schrobilgen, GJ AF Gerken, M Dixon, DA Schrobilgen, GJ TI The OsO4F-, OsO4F22-, and OsO3F3- anions, their study by vibrational and NMR spectroscopy and density functional theory calculations, and the X-ray crystal structures of [N(CH3)(4)][OsO4F] and [N(CH3)(4)][OsO3F3] SO INORGANIC CHEMISTRY LA English DT Article ID EFFECTIVE CORE POTENTIALS; HIGHER OXIDATION-STATES; BOND ORDERS; COORDINATION CHEMISTRY; MOLECULAR CALCULATIONS; RAMAN-SPECTROSCOPY; OSMIUM TETRAOXIDE; SCF THEORY; COMPLEXES; FLUORIDES AB The fluoride ion acceptor properties of OsO4 and OsO3F2 were investigated. The salts [N(CH3)(4)][OsO4F] and [N(CH3)(4)](2)[OsO4F2] were prepared by the reactions of OsO4 with stoichiometric amounts of [N(CH3)(4)][F] in CH3CN solvent, The salts [N(CH3)(4)][OsO3F3] and [NO][OsO3F3] were prepared by the Tractions of OsO3F2 With a stoichiometric amount of [N(CH3)(4)][F] in CH3CN solvent and with excess NOF, respectively. The OsO4F-anion was fully structurally characterized in the solid state by vibrational spectroscopy and by a single-crystal X-ray diffraction study of [N(CH3)(4)][OsO4F]: Abm2, a = 7.017(1) Angstrom, b = 11.401(2) Angstrom, c = 10.925(2) Angstrom, V = 874.1(3) Angstrom(3), Z = 4, and R = 0.0282 at -50 degrees C. The cis-OsO4F22- anion was characterized in the solid state by vibrational spectroscopy, and previous claims regarding the cis-OsO4F22- anion are shown to be erroneous. The fac-OsO3F3- anion was fully structurally characterized in CH3CN solution by F-19 NMR spectroscopy and in the solid state by vibrational spectroscopy of its N(CH3)(4+) and NO+ salts and by a single-crystal X-ray diffraction study of [N(CH3)(4)][OsO3F3]: C2/c, a = 16.347(4) Angstrom, b = 13.475(3) Angstrom, c = 11.436(3) Angstrom, beta = 134.128(4)degrees V = 1808.1(7) Angstrom(3), Z = 8, and R = 0.0614 at -117 DC. The geometrical parameters and vibrational frequencies of OsO4F-, Cis-OsO4F22-, monomeric OsO3F2, and fac-OsO3F3- and the fluoride affinities of OsO4 and monomeric OsO3F2 were calculated using density functional theory methods. C1 McMaster Univ, Dept Chem, Hamilton, ON L8S 4M1, Canada. Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP McMaster Univ, Dept Chem, 1280 Main St W, Hamilton, ON L8S 4M1, Canada. NR 66 TC 55 Z9 56 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 EI 1520-510X J9 INORG CHEM JI Inorg. Chem. PD SEP 18 PY 2000 VL 39 IS 19 BP 4244 EP 4255 DI 10.1021/ic000259i PG 12 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 356RR UT WOS:000089457100011 PM 11196919 ER PT J AU He, XM Taylor, TN Lillard, RS Walter, KC Nastasi, M AF He, XM Taylor, TN Lillard, RS Walter, KC Nastasi, M TI Bonding structure and properties of ion enhanced reactive magnetron sputtered silicon carbonitride films SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID CHEMICAL-VAPOR-DEPOSITION; DIAMOND-LIKE CARBON; H FILMS; TEMPERATURE; NITRIDE AB Amorphous silicon carbonitride (a-SiCN) films were synthesized by ion enhanced radio-frequency (rf) magnetron sputtering from a Si4C target using a mixture of Ar and N-2 gases. The oxidation resistance of the films was investigated in an oxygen atmosphere over the temperature range of 0-1000 degrees C. X-ray photoelectron spectroscopy showed that the a-SiCN films exhibited a well-defined Si-C-N bonding structure. The composition, density, hardness, and stress were uniquely characterized with respect to the average energy per deposited atom. Under optimum deposition conditions a-SiCN films can be prepared to exhibit high density (>2.6 g cm(-3)), high hardness (>25 GPa), and enhanced oxidization resistance at temperatures up to 800 degrees C. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP He, XM (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 20 TC 22 Z9 22 U1 1 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 SEP 18 PY 2000 VL 12 IS 37 BP L591 EP L597 DI 10.1088/0953-8984/12/37/101 PG 7 WC Physics, Condensed Matter SC Physics GA 360NY UT WOS:000089675200001 ER PT J AU Csaki, C Erlich, J Grojean, C Hollowood, TJ AF Csaki, C Erlich, J Grojean, C Hollowood, TJ TI General properties of the self-tuning domain wall approach to the cosmological constant problem SO NUCLEAR PHYSICS B LA English DT Article DE brane universe; localized gravity; self-tuning; cosmological constant ID SINGULARITIES; DIMENSIONS; HIERARCHY AB We study the dynamics of brane worlds coupled to a scalar field and gravity, and find that self-tuning of the cosmological constant is generic in theories with at most two branes or a single brane with orbifold boundary conditions. We demonstrate that singularities are generic in the self-tuned solutions compatible with localized gravity on the brane: we show that localized gravity with an infinitely large extra dimension is only consistent with particular fine-tuned values of the brane tension. The number of allowed brane tension values is related to the number of negative stationary points of the scalar bulk potential and, in the case of an oscillatory potential, the brane tension for which gravity is localized without singularities is quantized. We also examine a resolution of the singularities, and find that fine-tuning is generically reintroduced at the singularities in order to retain a static solution. However, we speculate that the presence of additional fields may restore self-tuning. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Theory Div T8, Los Alamos, NM 87545 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Univ Wales, Dept Phys, Swansea SA2 8PP, W Glam, Wales. RP Grojean, C (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. OI Hollowood, Timothy/0000-0002-3258-320X; grojean, christophe/0000-0002-7196-7361 NR 34 TC 162 Z9 164 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 SEP 18 PY 2000 VL 584 IS 1-2 BP 359 EP 386 DI 10.1016/S0550-3213(00)00390-4 PG 28 WC Physics, Particles & Fields SC Physics GA 351QX UT WOS:000089170600015 ER PT J AU Shafir, A Power, MP Whitener, GD Arnold, J AF Shafir, A Power, MP Whitener, GD Arnold, J TI Synthesis, structure, and properties of 1,1 '-diamino- and 1,1 '-diazidoferrocene SO ORGANOMETALLICS LA English DT Article ID DISUBSTITUTED FERROCENES; LIGANDS; PHOSPHINE; AMINOCOBALTOCENES; AMINOFERROCENES; MECHANISM; CHEMISTRY AB We report an improved synthesis of 1, 1'-diaminoferrocene, employing the reduction of 1,1'diazidoferrocene with H-2-Pd/C, along with extensive characterization data for both compounds. Diaminoferrocene undergoes a reversible 1e(-) oxidation in CH3CN at a potential of -602 mV us Fc(0/+), one of the most negative redox potentials for a ferrocene derivative. The chemical reversibility of this process was confirmed by isolation of the stable, 17-electron [Fc(NH2)(2)](+) cation as PF6-, OTf-, and TCNE- salts. In the solid state, diaminoferrocene exists in two conformations: one with the NH2 groups eclipsed, and the other with the NH2 groups offset by one-fifth turn around the Cp-Fe-Cp axis. Diazidoferrocene, on the other hand, exhibits only the fully eclipsed conformation in the solid state. The Fe-Cp(centroid) vectors in the diazidoferrocene molecules are roughly aligned with the crystallographic c-axis, and the molecules form layers perpendicular to this axis- The compound is thermally unstable at elevated temperatures, and rapid heating above its melting point results in explosion. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Arnold, J (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Shafir, Alexandr/D-1676-2009; Arnold, John/F-3963-2012 OI Shafir, Alexandr/0000-0002-8127-2299; Arnold, John/0000-0001-9671-227X NR 35 TC 120 Z9 120 U1 2 U2 22 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD SEP 18 PY 2000 VL 19 IS 19 BP 3978 EP 3982 DI 10.1021/om0004085 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 355PG UT WOS:000089393600031 ER PT J AU Appel, R Atoyan, GS Bassalleck, B Bergman, DR Brown, DN Cheung, N Dhawan, S Do, H Egger, J Eilerts, S Felder, C Fischer, H Gach, M Herold, W Issakov, VV Kaspar, H Kraus, DE Lazarus, DM Leipuner, L Lichard, P Lowe, J Lozano, J Ma, H Majid, W Menzel, W Pislak, S Poblaguev, AA Postoev, VE Proskurjakov, AL Rehak, P Robmann, P Sher, A Thompson, JA Truol, P Weyer, H Zeller, ME AF Appel, R Atoyan, GS Bassalleck, B Bergman, DR Brown, DN Cheung, N Dhawan, S Do, H Egger, J Eilerts, S Felder, C Fischer, H Gach, M Herold, W Issakov, VV Kaspar, H Kraus, DE Lazarus, DM Leipuner, L Lichard, P Lowe, J Lozano, J Ma, H Majid, W Menzel, W Pislak, S Poblaguev, AA Postoev, VE Proskurjakov, AL Rehak, P Robmann, P Sher, A Thompson, JA Truol, P Weyer, H Zeller, ME TI Improved limit on the rate of the decay K+ -> pi(+)mu(+)e(-) SO PHYSICAL REVIEW LETTERS LA English DT Article ID VIOLATION AB We report results of a search for the lepton-family number violating decay K+ --> pi(+) mu(+) e from data collected by experiment E865 in 1996 at the Alternating Gradient Synchroton of Brookhaven National Laboratory. We place an upper limit on the branching ratio at 3.9 x 10(-11) (90% C.L.). Together with results based on data collected in 1995 and an earlier experiment, E777, this result establishes a combined 90% confidence level upper limit on the branching ratio at 2.8 x 10(-11). We also report a new upper limit on the branching ratio for pi(0) --> mu(+) e(-) of 3.8 x 10(-10) (90% C.L.). C1 Yale Univ, Dept Phys, New Haven, CT 06511 USA. Univ Basel, Inst Phys, CH-4046 Basel, Switzerland. Univ Zurich, Inst Phys, CH-8057 Zurich, Switzerland. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. RP Appel, R (reprint author), Yale Univ, Dept Phys, New Haven, CT 06511 USA. RI Lichard, Peter/A-4459-2010 OI Lichard, Peter/0000-0003-1581-8545 NR 14 TC 18 Z9 19 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 SEP 18 PY 2000 VL 85 IS 12 BP 2450 EP 2453 DI 10.1103/PhysRevLett.85.2450 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500010 ER PT J AU Enzer, DG Schauer, MM Gomez, JJ Gulley, MS Holzscheiter, MH Kwiat, PG Lamoreaux, SK Peterson, CG Sandberg, VD Tupa, D White, AG Hughes, RJ James, DFV AF Enzer, DG Schauer, MM Gomez, JJ Gulley, MS Holzscheiter, MH Kwiat, PG Lamoreaux, SK Peterson, CG Sandberg, VD Tupa, D White, AG Hughes, RJ James, DFV TI Observation of power-law scaling for phase transitions in linear trapped ion crystals SO PHYSICAL REVIEW LETTERS LA English DT Article AB We report an experimental confirmation of the power-law relationship between the critical anisotropy parameter and ion number for the linear-to-zigzag phase transition in an ionic crystal. Our experiment uses laser cooled calcium ions confined in a linear radio-frequency trap. Measurements for up to ten ions are in good agreement with theoretical and numeric predictions. Implications on an upper limit to the size of data registers in ion trap quantum computers are discussed. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Enzer, DG (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, POB 1663, Los Alamos, NM 87545 USA. RI James, Daniel/B-9805-2009; White, Andrew/A-1088-2009 OI James, Daniel/0000-0003-3981-4602; White, Andrew/0000-0001-9639-5200 NR 18 TC 45 Z9 46 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 SEP 18 PY 2000 VL 85 IS 12 BP 2466 EP 2469 DI 10.1103/PhysRevLett.85.2466 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500014 ER PT J AU Murillo, MS AF Murillo, MS TI Critical wave vectors for transverse modes in strongly coupled dusty plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID ACOUSTIC-WAVES; DISPERSION AB Transverse collective modes of strongly coupled dusty plasmas are studied in the fluid phase. A memory function approach based on the generalized viscosity is employed to capture both the hydrodynamic limit and the second-moment sum rule. It is shown that shear modes do not exist at long wavelengths but do exist above a critical wave vector. Above the critical wave vector strong coupling gives rise to an incipient Brillouin structure in the dispersion. The emergence and damping of the shear mode is shown to depend on the generalized viscosity and a generalized relaxation time. Agreement with simulation data is shown to be excellent. C1 Univ Calif Los Alamos Natl Lab, Plasma Phys Grp, Los Alamos, NM 87545 USA. RP Murillo, MS (reprint author), Univ Calif Los Alamos Natl Lab, Plasma Phys Grp, MS B259, Los Alamos, NM 87545 USA. NR 16 TC 58 Z9 58 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 18 PY 2000 VL 85 IS 12 BP 2514 EP 2517 DI 10.1103/PhysRevLett.85.2514 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500026 ER PT J AU Abraham, DB Upton, PJ AF Abraham, DB Upton, PJ TI Orientation dependence of surface critical phenomena in antiferromagnets: Exact results in two dimensions SO PHYSICAL REVIEW LETTERS LA English DT Article ID INTERFACE PROFILE; ISING FERROMAGNET; ALLOYS; MODEL AB For an Ising antiferromagnet, we analyze exact expressions for the one- and two-point correlation functions fur spins on the edge of a square lattice with a magnetic field applied to the surface sites. Two different edge orientations, with respect to the crystal axes, are treated. At bulk criticality, we confirm that the surface universality class depends on the edge orientation and show the importance of having the bulk phase in a pure state. For the two-point function, we find a singularity in the correlation length due to depinning effects which we argue is also present in higher dimensions. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Univ Oxford, Dept Phys, Oxford OX1 3NP, England. Univ Essen Gesamthsch, Fachbereich Phys, D-45117 Essen, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. RP Abraham, DB (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, MS-B258, Los Alamos, NM 87545 USA. NR 17 TC 5 Z9 5 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 SEP 18 PY 2000 VL 85 IS 12 BP 2541 EP 2544 DI 10.1103/PhysRevLett.85.2541 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500033 ER PT J AU Dai, PC Fernandez-Baca, JA Wakabayashi, N Plummer, EW Tomioka, Y Tokura, Y AF Dai, PC Fernandez-Baca, JA Wakabayashi, N Plummer, EW Tomioka, Y Tokura, Y TI Short-range polaron correlations in the ferromagnetic La1-xCaxMnO3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLOSSAL-MAGNETORESISTANCE; LA1-XSRXMNO3; MANGANITES; TRANSITION; COLLAPSE; CHARGE AB We use neutron scattering to demonstrate the presence of lattice polarons and their short-range correlations fur several samples of La1-xCaxMnO3 in the Ca doping range 0.15 less than or equal to x less than or equal to 0.3. We establish the duping dependence of the orientation, commensuration, and coherence length of the polaron correlations and show that the populations of correlated and uncorrelated polarons are intimately related to the transport properties of the materials. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Keio Univ, Dept Phys, Kohoku Ku, Yokohama, Kanagawa 2238522, Japan. Univ Tennessee, Dept Phys, Knoxville, TN 37966 USA. JRCAT, Tsukuba, Ibaraki 3058562, Japan. Univ Tokyo, Dept Appl Phys, Tokyo 1138656, Japan. RP Dai, PC (reprint author), Oak Ridge Natl Lab, Div Solid State, POB 2008, Oak Ridge, TN 37831 USA. RI Dai, Pengcheng /C-9171-2012; Tokura, Yoshinori/C-7352-2009; Fernandez-Baca, Jaime/C-3984-2014 OI Dai, Pengcheng /0000-0002-6088-3170; Fernandez-Baca, Jaime/0000-0001-9080-5096 NR 17 TC 157 Z9 158 U1 2 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 SEP 18 PY 2000 VL 85 IS 12 BP 2553 EP 2556 DI 10.1103/PhysRevLett.85.2553 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500036 ER PT J AU Corson, J Orenstein, J Oh, S O'Donnell, J Eckstein, JN AF Corson, J Orenstein, J Oh, S O'Donnell, J Eckstein, JN TI Nodal quasiparticle lifetime in the superconducting state of Bi2Sr2CaCu2O8+delta SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUASI-PARTICLE SCATTERING; TEMPERATURE-DEPENDENCE; PENETRATION DEPTH; YBA2CU3O7-DELTA; CONDUCTIVITY; COHERENCE; INPLANE AB We have measured the complex conductivity sigma of a Bi2Sr2CaCu2O8+delta thin film between 0.2 and 0.8 THz. We find sigma in the superconducting state to be well described as the sum of contributions from quasiparticles, condensate, and order parameter fluctuations which draw 30% of the spectral weight from decomposition yields a quasiparticle scattering rate on the the condensate. Hn analysts based on this order of k(B)T/h for temperatures below T-c. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Orenstein, Joseph/I-3451-2015 NR 25 TC 81 Z9 81 U1 2 U2 6 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 SEP 18 PY 2000 VL 85 IS 12 BP 2569 EP 2572 DI 10.1103/PhysRevLett.85.2569 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500040 ER PT J AU Bogdanov, PV Lanzara, A Kellar, SA Zhou, XJ Lu, ED Zheng, WJ Gu, G Shimoyama, JI Kishio, K Ikeda, H Yoshizaki, R Hussain, Z Shen, ZX AF Bogdanov, PV Lanzara, A Kellar, SA Zhou, XJ Lu, ED Zheng, WJ Gu, G Shimoyama, JI Kishio, K Ikeda, H Yoshizaki, R Hussain, Z Shen, ZX TI Evidence for an energy scale for quasiparticle dispersion in Bi2Sr2CaCu2O8 SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-C SUPERCONDUCTORS; CUPRATE SUPERCONDUCTORS; ELECTRONIC-STRUCTURE; NEUTRON-SCATTERING; STATE; PHOTOEMISSION; DYNAMICS; TEMPERATURE; SPECTRA AB Quasiparticle dispersion in Bi2Sr2CaCu2O8 is investigated with improved angular resolution as a function of temperature and doping. Unlike the linear dispersion predicted by the band calculation, the data show a sharp break in dispersion at 50 +/- 15 meV binding energy where the velocity changes by a factor of 2 or more. This change provides an energy scale in the quasiparticle self-energy. This break in dispersion is evident at and away from the cl-wave node line, but the magnitude of the dispersion change decreases with temperature and with increasing doping. C1 Stanford Univ, Dept 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 New S Wales, Sch Phys, Kensington, NSW 2033, Australia. Univ Tokyo, Dept Appl Chem, Tokyo 1138656, Japan. Univ Tsukuba, Inst Appl & Cryogen Ctr, Tsukuba, Ibaraki 305, Japan. RP Stanford Univ, Dept Phys, Stanford, CA 94305 USA. NR 41 TC 224 Z9 225 U1 0 U2 10 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 SEP 18 PY 2000 VL 85 IS 12 BP 2581 EP 2584 DI 10.1103/PhysRevLett.85.2581 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500043 ER PT J AU Chang, EK Rohlfing, M Louie, SG AF Chang, EK Rohlfing, M Louie, SG TI Excitons and optical properties of alpha-quartz SO PHYSICAL REVIEW LETTERS LA English DT Article ID AB-INITIO CALCULATION; SEMICONDUCTORS; EXCITATIONS; ABSORPTION; INSULATORS AB We present an ail initio study of the optical properties of ru-quartz. The absorption spectrum is calculated by solving the Bethe-Salpeter equation for the interacting electron-hole system and found to be in excellent agreement with the measured spectrum up to 10 eV above the absorption threshold. We find that excitonic effects are crucial in understanding the sharp features in the absorption spectrum in this energy range. They are also crucial in the nb initio computation of the static dielectric constant, significantly enhancing its value. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Munster, Inst Theoret Phys 2, D-48149 Munster, Germany. RP Chang, EK (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 15 TC 70 Z9 70 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 18 PY 2000 VL 85 IS 12 BP 2613 EP 2616 DI 10.1103/PhysRevLett.85.2613 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500051 ER PT J AU Hummer, G Garcia, AE Garde, S AF Hummer, G Garcia, AE Garde, S TI Conformational diffusion and helix formation kinetics SO PHYSICAL REVIEW LETTERS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; LASER TEMPERATURE-JUMP; FAST EVENTS; FOLDING DYNAMICS; ALPHA-HELIX; PEPTIDE; PROTEINS; PATHWAYS; THERMODYNAMICS; MECHANISM AB The lime, temperature, and sequence dependences of helix formation kinetics of fully atomistic peptide models in explicit solvent are described quantitatively by a diffusive search within the coil state with barrierless transitions into the helical state. Conformational diffusion leads to nonexponential kinetics and jump-width dependences in temperature jump experiments. C1 NIDDKD, Phys Chem Lab, NIH, Bethesda, MD 20892 USA. Univ Calif Los Alamos Natl Lab, Theoret Biol & Biophys Grp T10, Los Alamos, NM 87545 USA. Rensselaer Polytech Inst, Dept Chem Engn, Troy, NY 12180 USA. RP Hummer, G (reprint author), NIDDKD, Phys Chem Lab, NIH, Bldg 5, Bethesda, MD 20892 USA. RI Garde, Shekhar/C-3060-2008; Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 36 TC 84 Z9 85 U1 2 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 SEP 18 PY 2000 VL 85 IS 12 BP 2637 EP 2640 DI 10.1103/PhysRevLett.85.2637 PG 4 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500057 PM 10978126 ER PT J AU Moretto, LG Breus, D Phair, L Wozniak, GJ AF Moretto, LG Breus, D Phair, L Wozniak, GJ TI Comment on "experimental evidence for dynamical decay of finite nuclear matter" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Moretto, LG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 1 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 18 PY 2000 VL 85 IS 12 BP 2645 EP 2645 DI 10.1103/PhysRevLett.85.2645 PG 1 WC Physics, Multidisciplinary SC Physics GA 355NV UT WOS:000089392500059 ER PT J AU Kim, H Grimsditch, M Anthony, TR Ramdas, AK Rodriguez, S AF Kim, H Grimsditch, M Anthony, TR Ramdas, AK Rodriguez, S TI Infrared and Raman spectroscopy of acceptors in diamond: Boron impurities SO PHYSICA STATUS SOLIDI A-APPLIED RESEARCH LA English DT Article; Proceedings Paper CT 5th International Workshop on Surface and Bulk Defects in CVD Diamond and Related Films CY MAR 02-03, 2000 CL DIEPENBEEK HASSELT, BELGIUM SP FWO Vlaanderen, Sci Res Community ID ISOTOPICALLY CONTROLLED DIAMONDS; SEMICONDUCTING DIAMOND; BLUE DIAMONDS; ELECTRONIC RAMAN; SPECTRA AB Substitutional boron accepters in nitrogen free, naturally occurring (type IIb) diamonds as well as in man-made diamonds exhibit characteristic Lyman transitions in the infrared, originating in the 1s(p(3/2)):Gamma(8) ground stale or in the thermally populated 1s(p(1/2)):Gamma(7) spin-orbit counterpart. In addition to the infrared Lyman lines having p-like final states, the 1s(p(3/2)) --> 1s(p(1/2)) transition (Delta') appears as an electronic Raman line; under the high resolution of a Fabry-Perot interferometer, the Delta' line exhibits a Jahn-Teller splitting. A comparison of the infrared and Raman spectra of boron-doped natural and C-13 diamonds shows self-energy shifts in their corresponding features; The theoretical expression for the absolute cross section of the electronic Raman line at Delta' and that experimentally deduced from an intercomparison of intensities of Delta', Brillouin components and the zone center optical phonon, recorded in the same experiment, yield the acceptor concentration. The Zeeman effect of Delta' exhibits its predicted eight components and the four transitions within the Gamma(8) multiplet. A theory formulated in terms of the pronounced hole mass anisotropy explains the observed level ordering, polarizations of the Zeeman components, and the sign and magnitude of the g-factors of the hole. Besides being of basic scientific interest, spectroscopy of accepters and donors is significant in characterizing diamond as a material for solid state electronics. C1 Argonne Natl Lab, Argonne, IL 60439 USA. GE Corp Res & Dev, Schenectady, NY 12309 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. RP Kim, H (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 34 TC 1 Z9 1 U1 2 U2 14 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0031-8965 J9 PHYS STATUS SOLIDI A JI Phys. Status Solidi A-Appl. Res. PD SEP 16 PY 2000 VL 181 IS 1 BP 51 EP 58 DI 10.1002/1521-396X(200009)181:1<51::AID-PSSA51>3.0.CO;2-O PG 8 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 363GV UT WOS:000089827900013 ER PT J AU Praphairaksit, N Houk, RS AF Praphairaksit, N Houk, RS TI Reduction of mass bias and matrix effects in inductively coupled plasma mass spectrometry with a supplemental electron source in a negative extraction lens SO ANALYTICAL CHEMISTRY LA English DT Article ID ENLARGED SAMPLING ORIFICE; OFFSET ION LENS; SPACE-CHARGE; ICP-MS; INTERFERENCES; INTERFACE AB Electrons from a heated tungsten filament are created inside the extraction lens and driven out toward the skimmer. These electrons move through the ion path and reduce space charge effects between positive ions in the beam. The ion transmission efficiency is improved by factors of two (for Pb+) to 27 (for Li+). The greater sensitivity improvement for low-mass ions leads to a substantial reduction in mass bias. With the additional electrons, MO+/M+ and M2+/M+ abundance ratios increase but can be minimized with a small reduction in aerosol gas now rate. No new background ions are observed with this technique. Matrix effects can be significantly diminished when the electron source is operated under the high electron current mode. The mass dependence of matrix-induced suppression of analyte signals is essentially eliminated. Using now injection analysis to minimize solid deposition, the technique can tolerate Na matrix up to 10 000 ppm (1%) with only similar to 15% loss of analyte sensitivity. C1 Iowa State Univ, Dept Chem, US Dept Energy, Ames Lab, Ames, IA 50011 USA. RP Houk, RS (reprint author), Iowa State Univ, Dept Chem, US Dept Energy, Ames Lab, Ames, IA 50011 USA. NR 15 TC 18 Z9 19 U1 1 U2 6 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 SEP 15 PY 2000 VL 72 IS 18 BP 4435 EP 4440 DI 10.1021/ac000590j PG 6 WC Chemistry, Analytical SC Chemistry GA 354AU UT WOS:000089308300024 ER PT J AU Lefebvre-Brion, H Ng, CY AF Lefebvre-Brion, H Ng, CY TI Pulsed-field ionization photoelectron spectrum of the A(2)Pi state of CO+ SO CHEMICAL PHYSICS LETTERS LA English DT Article ID PHOTOIONIZATION; SPECTROSCOPY; INTENSITY; MOLECULES AB Calculations of the pulsed-field ionization photoelectron (PR-PE) spectra of the CO+ A (2)Pi, upsilon(+) = 1 reproduce relatively well the experimental spectra including their intensity anomalies in the ratio of the two subbands, for rotational temperatures of respectively 12 and 298 K. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Paris Sud, Photophys Mol Lab, F-91405 Orsay, France. Iowa State Univ, Ames Lab, USDOE, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Lefebvre-Brion, H (reprint author), Univ Paris Sud, Photophys Mol Lab, Bat 213, F-91405 Orsay, France. NR 8 TC 1 Z9 1 U1 0 U2 0 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 SEP 15 PY 2000 VL 327 IS 5-6 BP 404 EP 408 DI 10.1016/S0009-2614(00)00797-1 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 353XZ UT WOS:000089301900021 ER PT J AU Chao, C Saito, S Kang, J Anderson, CW Appella, E Xu, Y AF Chao, C Saito, S Kang, J Anderson, CW Appella, E Xu, Y TI p53 transcriptional activity is essential for p53-dependent apoptosis following DNA damage SO EMBO JOURNAL LA English DT Article DE acetylation; DNA damage; phosphorylation; stability; transactivation ID WILD-TYPE P53; CELL-CYCLE ARREST; TRANSACTIVATION DOMAIN; ATAXIA-TELANGIECTASIA; IONIZING-RADIATION; TERMINAL DOMAIN; PROTEIN-KINASE; ES CELLS; PHOSPHORYLATION; ACTIVATION AB p53-mediated transcription activity is essential for cell cycle arrest, but its importance for apoptosis remains controversial. To address this question, we employed homologous recombination and LoxP/Cre-mediated deletion to produce mutant murine embryonic stem (ES) cells that express p53 with Gin and Ser in place of Leu25 and Trp26, respectively. p53(Gln25Ser26) was stable but did not accumulate after DNA damage; the expression of p21/Waf1 and PERP was not induced, and p53-dependent repression of MAP4 expression was abolished. Therefore, p53(Gln25Ser26) is completely deficient in transcriptional activation and repression activities. After DNA damage by UV radiation, p53(Gln25Ser26) was phosphorylated at Ser18 but was not acetylated at C-terminal sites, and its DNA binding activity did not increase, further supporting a role for p53 acetylation in the activation of sequence-specific DNA binding activity. Most importantly, p53(Gln25Ser26) mouse thymocytes and ES cells, like p53(-/-) cells, did not undergo DNA damage-induced apoptosis. We conclude that the transcriptional activities of p53 are required for p53-dependent apoptosis. C1 Univ Calif San Diego, Dept Biol, La Jolla, CA 92093 USA. NCI, Cell Biol Lab, NIH, Bethesda, MD 20892 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Xu, Y (reprint author), Univ Calif San Diego, Dept Biol, 9500 Gilman Dr, La Jolla, CA 92093 USA. FU NCI NIH HHS [CA77563, R01 CA077563]; NIGMS NIH HHS [GM52825] NR 57 TC 192 Z9 194 U1 0 U2 7 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0261-4189 J9 EMBO J JI Embo J. PD SEP 15 PY 2000 VL 19 IS 18 BP 4967 EP 4975 DI 10.1093/emboj/19.18.4967 PG 9 WC Biochemistry & Molecular Biology; Cell Biology SC Biochemistry & Molecular Biology; Cell Biology GA 358QQ UT WOS:000089569100011 PM 10990460 ER PT J AU Wigley, TML Santer, BD Taylor, KE AF Wigley, TML Santer, BD Taylor, KE TI Correlation approaches to detection SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLIMATE-CHANGE; NATURAL VARIABILITY; FINGERPRINT METHOD; GREENHOUSE GASES; ATTRIBUTION; SEARCH AB Criticisms leveled at the use of pattern correlation methods in climate-change detection studies are addressed. We first explain how spatial autocorrelation effects are accounted for. We then show why it is important to consider both pattern similarity and spatial-mean results in detection studies, and evaluate a mean-square-error statistic in this context. We also show that the use of changes in climate, as opposed to absolute climate states, does not lead to spurious trends in the pattern correlation statistic R(t). In doing this, we explain how previous pattern correlation studies account for "time arrow" effects in considering changes relative to an arbitrary reference year. We conclude that criticisms of the pattern correlation method are without substance. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Calif Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. RP Wigley, TML (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. RI Wigley, Tom/B-4705-2008; Taylor, Karl/F-7290-2011; Santer, Benjamin/F-9781-2011 OI Taylor, Karl/0000-0002-6491-2135; NR 19 TC 6 Z9 6 U1 0 U2 2 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 SEP 15 PY 2000 VL 27 IS 18 BP 2973 EP 2976 DI 10.1029/2000GL011611 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 355MX UT WOS:000089390400038 ER PT J AU Millett, J Gray, GT Bourne, N AF Millett, J Gray, GT Bourne, N TI The shock Hugoniot of the intermetallic alloy Ti-46.5Al-2Nb-2Cr SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAMMA-TITANIUM ALUMINIDES; HIGH-STRAIN RATE; MECHANICAL-PROPERTIES; DYNAMIC COMPACTION; HIGH-TEMPERATURE; COMPOUND; DEFORMATION; WAVES AB Plate impact experiments were conducted on a gamma-titanium aluminide (TiAl) based ordered intermetallic alloy. Stress measurements were recorded using manganin stress gauges supported on the back of TiAl targets using polymethylmethacrylate windows. The Hugoniot in stress-particle velocity space for this TiAl alloy was deduced using impedance matching techniques. The results in this study are compared to the known Hugoniot data of the common alpha-beta engineering Ti-based alloy Ti-6Al-4V. The results of the current study on the intermetallic alloy TiAl support that TiAl possesses a significantly higher stress for a given particle velocity than the two-phase Ti-6Al-4V alloy. (C) 2000 American Institute of Physics. [S0021-8979(00)04918-5]. C1 Cranfield Univ, Royal Mil Coll Sci, Swindon SN6 8LA, Wilts, England. Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Millett, J (reprint author), Cranfield Univ, Royal Mil Coll Sci, Swindon SN6 8LA, Wilts, England. EM j.millett@rmcs.cranfield.ac.uk RI Bourne, Neil/A-7544-2008 NR 32 TC 20 Z9 20 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 2000 VL 88 IS 6 BP 3290 EP 3294 AR PII [S0021-8979(00)04918-5] DI 10.1063/1.1288500 PG 5 WC Physics, Applied SC Physics GA 349GB UT WOS:000089034700022 ER PT J AU Brennan, S Stephenson, GB Fuoss, PH Kisker, DW Lavoie, C Evans-Lutterodt, KL AF Brennan, S Stephenson, GB Fuoss, PH Kisker, DW Lavoie, C Evans-Lutterodt, KL TI Silicon-induced faceting of vicinal GaAs(001) SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID VAPOR-PHASE EPITAXY; X-RAY-SCATTERING; SCANNING-TUNNELING-MICROSCOPY; MULTIATOMIC STEP FORMATION; ORIENTATION DEPENDENCE; IMPURITY INCORPORATION; HYDROGEN AMBIENT; SI(001) SURFACES; SI(113) SURFACES; CRYSTAL-GROWTH AB This article presents in situ x-ray diffraction studies of the evolution of the morphology of 0.5 degrees-miscut vicinal GaAs(001) surfaces during and following undoped and silicon-doped growth using organometallic vapor-phase epitaxy. Undoped growth leads to ordered monolayer steps. However, growth in the presence of silicon destabilizes this surface morphology and triggers faceting. Coarsening of the facet size proceeds even after the growth has stopped and results in large singular regions of GaAs(001) surface separated by step bunches. Dosing the surface with silicon without growing material does not trigger faceting. Growth of undoped GaAs on faceted surfaces recovers the initial state of ordered monolayer steps. (C) 2000 American Institute of Physics. [S0021-8979(00)06419-7]. C1 Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. AT&T Labs, Florham Park, NJ 07932 USA. Cielo Commun Inc, Broomfield, CO 80021 USA. IBM Corp, Div Res, TJ Watson Res Ctr, Yorktown Heights, NY 10598 USA. Lucent Technol, Murray Hill, NJ 07974 USA. RP Brennan, S (reprint author), Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RI Schaff, William/B-5839-2009 NR 46 TC 3 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 2000 VL 88 IS 6 BP 3367 EP 3376 AR PII [S0021-8979(00)06419-7] DI 10.1063/1.1289482 PG 10 WC Physics, Applied SC Physics GA 349GB UT WOS:000089034700033 ER PT J AU Zharkov, DO Rosenquist, TA Gerchman, SE Grollman, AP AF Zharkov, DO Rosenquist, TA Gerchman, SE Grollman, AP TI Substrate specificity and reaction mechanism of murine 8-oxoguanine-DNA glycosylase SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID BASE-EXCISION-REPAIR; 7,8-DIHYDRO-8-OXOGUANINE DNA GLYCOSYLASE; OXIDATIVELY DAMAGED DNA; ESCHERICHIA-COLI MUTY; DEOXYRIBOPHOSPHODIESTERASE DRPASE ACTIVITY; NUCLEIC-ACID ADDUCTS; SACCHAROMYCES-CEREVISIAE; FPG PROTEIN; CATALYTIC MECHANISM; HUMAN HOMOLOG AB Genomic DNA is prone to oxidation by reactive oxygen species. A major product of DNA oxidation is the miscoding base 8-oxoguanine (8-oxoG). The mutagenic effects of 8-oxoG in mammalian cells are prevented by a DNA repair system consisting of 8-oxoguanine-DNA glycosylase (Ogg1), adenine-DNA glycosylase, and 8-oxo-dGTPase. We have cloned, overexpressed, and characterized mOgg1, the product of the murine ogg1 gene. mOgg1 is a DNA glycosylase/AP lyase belonging to the endonuclease III family of DNA repair enzymes. The AP lyase activity of mOgg1 is significantly lower than its glycosylase activity. mOgg1 releases 8-oxoG from DNA when paired with C, T, or G, but efficient DNA strand nicking is observed only with 8-oxoG:C. Binding of mOgg1 to oligonucleotides containing 8-oxoG:C is strong (K-D = 51.5 nM), unlike other mispairs. The average residence time for mOgg1 bound to substrate containing 8-oxoG:C is 18.3 min; the time course for accumulation of the NaBH4-sensitive intermediate suggests a two-step reaction mechanism. Various analogs of 8-oxoG were tested as substrates for mOgg1. An electron-withdrawing or hydrogen bond acceptor moiety at CS is required for efficient binding of mOgg1. A substituent at C6 and a keto group at C8 are required for cleavage. The proposed mechanism of 8-oxoG excision involves protonation of O-8 Or the deoxyribose oxygen moiety. C1 SUNY Stony Brook, Biol Chem Lab, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Pharmacol Sci, Stony Brook, NY 11794 USA. Russian Acad Sci, Novosibirsk Bioorgan Chem Inst, Siberian Div, Novosibirsk 630090, Russia. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. RP Zharkov, DO (reprint author), SUNY Stony Brook, 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 85 TC 147 Z9 151 U1 1 U2 5 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 SEP 15 PY 2000 VL 275 IS 37 BP 28607 EP 28617 DI 10.1074/jbc.M002441200 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 354KY UT WOS:000089330700038 PM 10884383 ER PT J AU Bowles, RK McGraw, R Schaaf, P Senger, B Voegel, JC Reiss, H AF Bowles, RK McGraw, R Schaaf, P Senger, B Voegel, JC Reiss, H TI A molecular based derivation of the nucleation theorem SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MACROSCOPIC MOTHER PHASE; GAS-LIQUID NUCLEATION; HOMOGENEOUS NUCLEATION; REVERSIBLE WORK; PHYSICAL CLUSTERS; BINARY NUCLEI; HIGH-PRESSURE; VAPOR; EMBRYO; FLUIDS AB We show that, for condensation in an almost ideal vapor, the nucleation theorem is essentially a consequence of the law of mass action. The usual form of the theorem, with the effects of the translational degrees of freedom of the cluster included, is then derived using statistical mechanics and molecular theory, but only under the assumptions that the cluster excludes a volume to the surrounding vapor and that the vapor is ideal. The form of the result obtained via molecular theory is such that it appears unlikely (but not impossible) that the theorem remains valid for cases when the vapor is nonideal. This suggests that further work is necessary before the theorem can be regarded as established. We also consider the effects of the presence of a carrier gas. (C) 2000 American Institute of Physics. [S0021- 9606(00)50935-0]. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Inst Charles Sadron, CNRS, ULP, F-67083 Strasbourg, France. Ecole Europeenne Chem Polymeres & Mat Strasbourg, F-67008 Strasbourg, France. Univ Strasbourg 1, Federat Rech Odontol, INSERM, U424, F-67085 Strasbourg, France. RP Bowles, RK (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, 405 Hilgard Ave, Los Angeles, CA 90095 USA. RI Bowles, Richard/C-5937-2009; SCHAAF, Pierre/J-2751-2016 OI Bowles, Richard/0000-0003-1664-0590; SCHAAF, Pierre/0000-0001-7423-5492 NR 35 TC 29 Z9 29 U1 1 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 SEP 15 PY 2000 VL 113 IS 11 BP 4524 EP 4532 AR PII [S0021-9606(00)50935-0] DI 10.1063/1.1288802 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 351DC UT WOS:000089139900006 ER PT J AU Peterson, KA AF Peterson, KA TI An accurate global ab initio potential energy surface for the X(1)A ' electronic state of HOBr SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; CORRELATED MOLECULAR CALCULATIONS; ABSORPTION CROSS-SECTIONS; GAUSSIAN-BASIS SETS; MANY-MODE SYSTEMS; WAVE-FUNCTIONS; DIPOLE-MOMENT; VARIATIONAL CALCULATIONS; STRATOSPHERIC CHEMISTRY; ROVIBRATIONAL ENERGIES AB A global, analytical potential energy surface for the ground electronic state of HOBr has been determined using highly correlated multireference configuration interaction wave functions and explicit basis set extrapolations of large correlation consistent basis sets. The ab initio data have been fit to an analytical functional form that accurately includes both the HOBr and HBrO minima, as well as all dissociation asymptotes. Small adjustments to this surface are made based on the limited experimental data available and by indirectly taking into account the effects of spin-orbit coupling on the OH+Br dissociation channel. Vibrational energy levels are calculated variationally for both HOBr and HBrO up to the OH+Br dissociation limit using a truncation/recoupling method. The HOBr isomer is calculated to contain 708 bound vibrational energy levels, while the HBrO minimum lies above the OH+Br dissociation limit but is calculated to have 74 "quasibound," localized eigenstates. Infrared intensities for all of these vibrational transitions are also calculated using MRCI dipole moment functions. The assignment of the HOBr states is complicated by strong stretch-bend resonances even at relatively low energies. In contrast to the HOCl case, these state mixings made it particularly difficult to assign the relatively intense OH overtone bands above v(1)=2. The vibrational density of states of HOBr at the OH+Br dissociation limit is determined to be 0.16 states/cm(-1). Comparisons to recent work on HOCl using similar methods are made throughout. (C) 2000 American Institute of Physics. [S0021-9606(00)30235-5]. C1 Washington State Univ, Dept Chem, Richland, WA 99352 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Peterson, KA (reprint author), Washington State Univ, Dept Chem, 2710 Univ Dr, Richland, WA 99352 USA. NR 83 TC 43 Z9 48 U1 0 U2 5 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 SEP 15 PY 2000 VL 113 IS 11 BP 4598 EP 4612 AR PII [S0021-9606(00)30235-5] DI 10.1063/1.1288913 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 351DC UT WOS:000089139900014 ER PT J AU White, JA Schwegler, E Galli, G Gygi, F AF White, JA Schwegler, E Galli, G Gygi, F TI The solvation of Na+ in water: First-principles simulations SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DILUTE AQUEOUS-SOLUTIONS; MOLECULAR-DYNAMICS SIMULATION; DENSITY-FUNCTIONAL THEORY; NEUTRON-DIFFRACTION; MD SIMULATIONS; ION SOLVATION; MONTE-CARLO; X-RAY; HYDRATION; SODIUM AB First-principles molecular dynamics simulations have been performed on the solvation of Na+ in water. Consistent with the available experimental data, we find that the first solvation shell of Na+ contains on average 5.2 water molecules. A significant number of water exchanges between the first and second solvation shells are observed. However, the simulations are not long enough to reliably measure the rate of water exchange. Contrary to several previous studies, we do not find any effect of Na+ on the orientation of water molecules outside of the first solvation shell. Furthermore, the complete set of structural properties determined by first-principles molecular dynamics is not predicted by any of the known classical simulations. (C) 2000 American Institute of Physics. [S0021-9606(00)50435-8]. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP White, JA (reprint author), Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94550 USA. EM white65@llnl.gov RI Schwegler, Eric/F-7294-2010; Schwegler, Eric/A-2436-2016 OI Schwegler, Eric/0000-0003-3635-7418 NR 39 TC 168 Z9 173 U1 4 U2 22 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 15 PY 2000 VL 113 IS 11 BP 4668 EP 4673 AR PII [S0021-9606(00)50435-8] DI 10.1063/1.1288688 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 351DC UT WOS:000089139900022 ER PT J AU Lazar, IM Ramsey, RS Jacobson, SC Foote, RS Ramsey, JM AF Lazar, IM Ramsey, RS Jacobson, SC Foote, RS Ramsey, JM TI Novel microfabricated device for electrokinetically induced pressure flow and electrospray ionization mass spectrometry SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article; Proceedings Paper CT Analytical Separations 2000 Symposium CY OCT 13-16, 1999 CL VAALS, NETHERLANDS DE microchips; interfaces; CE-MS; instrumentation; mass spectrometry; electrospray ionization; peptides ID CAPILLARY-ELECTROPHORESIS; PROTEIN IDENTIFICATIONS; DEAD VOLUME; MICROCHIP; PEPTIDES AB A novel microchip device for electrospray ionization has been fabricated and interfaced to a time-of-flight mass spectrometer. Fluid is electrokinetically transported through the chip to a fine fused-silica capillary inserted directly into a channel at the edge of the device. Electrospray is established at the tip of the capillary, which assures a stable, efficient spray. The electric potential necessary for electrospray generation and the voltage drop for electroosmotic pumping are supplied through an electrically permeable glass membrane contacting the fluidic channel holding the capillary. The membrane is fabricated on the microchip using standard photolithographic and wet chemical etching techniques. Performance relative to other microchip electrospray sources has been evaluated and the device tested for potential use as a platform for on-line electrophoretic detection. Sensitivity was found to be approximately three orders of magnitude better than spraying from the flat edge of the chip. The effect of the capillary on electroosmotic flow was examined both experimentally and theoretically. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Ramsey, JM (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. OI Lazar, Iulia/0000-0001-7746-7889 NR 23 TC 50 Z9 53 U1 4 U2 13 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 SEP 15 PY 2000 VL 892 IS 1-2 BP 195 EP 201 DI 10.1016/S0021-9673(00)00335-6 PG 7 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 353EX UT WOS:000089262800015 PM 11045489 ER PT J AU Tsouris, C Shin, WT Yiacoumi, S DePaoli, DW AF Tsouris, C Shin, WT Yiacoumi, S DePaoli, DW TI Electrohydrodynamic velocity and pumping measurements in water and alcohols SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE electrostatic spraying; electroatomization; electrohydrodynamic flow; EHD; microbubbles ID ELECTROSTATIC DISPERSION; NONCONDUCTIVE FLUIDS; CONDUCTIVE FLUIDS; FIELD; LIQUIDS; CONVECTION; SIZE; AIR AB Bubble and particle velocities in water and alcohols, under the influence of an electric field, were investigated in this work. Air bubbles were injected into the liquids through an electrified metal capillary insulated by glass with its tip left exposed. The end of the capillary from which the bubbles were released was conical in shape. Due to an electric field formed between the noninsulated capillary tip and a ground electrode immersed in the solvent, small bubbles were formed and used as tracers for the electrohydrodynamic (EHD) flow held. The pressure inside the capillary was measured for all liquids used in this study. For water, ethanol, and n-propanol, it was found that, at relatively low applied voltage, the pressure increases with voltage, reaches a maximum (pressure breakpoint), and then sharply decreases. This behavior is a result of the competition between the electric force appearing at the interface and the force due to the Ef-LD flow near the capillary tip. The electric force tends to increase the pressure inside the capillary, while the EHD flow tends to decrease this pressure. For isopropanol and butanol, the pressure breakpoint was not observed in the range of voltage applied in the experiments. The EHD flow velocity was measured by using microbubbles and particles as flow tracers. An adaptive phase-Doppler velocimeter was employed to measure the velocity of bubbles, while the velocity of particles was measured by trajectory visualization of fluorescent particles. A discrepancy was observed between the two methods because of the location at which the measurements were made. It was found that average velocities of both bubbles and particles increase linearly with applied voltage. Experiments were also conducted to investigate pumping of water, which is a result of the EHD velocity near the capillary tip. The pumping flow rate was linearly related to the applied voltage and ag reed well with EHD velocity measurements obtained from particle trajectories. (C) 2000 Academic Press. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. RP Tsouris, C (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. RI Tsouris, Costas/C-2544-2016 OI Tsouris, Costas/0000-0002-0522-1027 NR 37 TC 6 Z9 6 U1 0 U2 10 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD SEP 15 PY 2000 VL 229 IS 2 BP 335 EP 345 DI 10.1006/jcis.2000.7056 PG 11 WC Chemistry, Physical SC Chemistry GA 355MY UT WOS:000089390500003 ER PT J AU Sasaki, DY Carpick, RW Burns, AR AF Sasaki, DY Carpick, RW Burns, AR TI High molecular orientation in mono- and trilayer polydiacetylene films imaged by atomic force microscopy SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE polydiacetylene; Langmuir films; AFM; horizontal deposition; molecular orientation ID LANGMUIR-BLODGETT-FILMS; WATER INTERFACE; MONOLAYERS AB Atomically flat monolayer and trilayer films of polydiacetylenes have been prepared on mica and silicon using a horizontal deposition technique from a pure wafer subphase. Langmuir films of 10,12-pentacosadiynoic acid (I) and N-(2-ethanol)-10,12-pentacosadiynamide (II) were compressed to 20 mN/m and subsequently polymerized by UV irradiation at the air-water interface. Blue and red forms of the films were prepared by varying exposure times and incident power. Polymerization to the blue-phase films produced slight contractions of 2 and 5% for the films of II and I, respectively. Longer UV exposures yielded red-phase films with dramatic film contraction of 15 and 32% for II and I, respectively. The horizontal deposition technique provided transfer ratios of unity with minimal film stress or structure modification. Atomic force microscopy images revealed nearly complete coverage of the substrate with atomically flat films. Crystalline domains of up to 100 micrometers of highly oriented polydiacetylene molecules were observed. The results reported herein provide insight into the roles of molecular packing and chain orientations in converting the monomeric film to the polymerized blue and red phases. (C) 2000 Academic Press. C1 Sandia Natl Labs, Biomol Mat & Interface Sci Dept, Albuquerque, NM 87185 USA. RP Sasaki, DY (reprint author), Sandia Natl Labs, Biomol Mat & Interface Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 23 TC 59 Z9 59 U1 5 U2 17 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD SEP 15 PY 2000 VL 229 IS 2 BP 490 EP 496 DI 10.1006/jcis.2000.7043 PG 7 WC Chemistry, Physical SC Chemistry GA 355MY UT WOS:000089390500019 ER PT J AU Siegel, RW Allen, B Pavlik, P Marks, JD Bradbury, A AF Siegel, RW Allen, B Pavlik, P Marks, JD Bradbury, A TI Mass spectral analysis of a protein complex using single-chain antibodies selected on a peptide target: Applications to functional genomics SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE single-chain variable fragment; phage display; peptide selection; functional genomics; mass spectrometry ID ANTIGENIC DETERMINANTS; PHAGE ANTIBODIES; LIBRARIES; SCALE; SITES; SPECTROMETRY; DISRUPTION; RECOGNIZE; AFFINITY; LOCATION AB Genome projects are identifying an ever-increasing number of genes, accelerating the need for reagents to study the expression of these genes and elucidate the function and cellular location of the gene products. Our goal was to develop a strategy to allow human single-chain variable fragment (scFv) antibodies to be used for these endeavors. A library containing 7x10(9) individual variants was displayed by bacteriophage and selected against a biotinylated peptide corresponding to the C-terminal 15 amino acid residues of Ku86, one component of a heterodimer involved in double-stranded DNA break repair. Four unique scFv antibodies were recovered that not only recognized the selected peptide, but also the intact protein. Three of the scFv antibodies were expressed in soluble form and recognized Ku86 by Western analysis. The affinity of one of the scFv antibodies for Ku86 was 16 nM as measured by BIAcore analysis. scFv immunoprecipitation of Ku86 also isolated the other component of the heterodimer, Ku70, as determined by Western analysis and mass spectrometry. These results demonstrate the utility of scFv antibodies as invaluable reagents for functional genomics. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA. Univ Calif San Francisco, Dept Anesthesia, San Francisco, CA 94143 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. SISSA, Int Sch Adv Studies, I-34014 Trieste, Italy. RP Bradbury, A (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, POB 1663, Los Alamos, NM 87545 USA. OI Siegel, Robert/0000-0002-0833-5580 NR 28 TC 15 Z9 15 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD SEP 15 PY 2000 VL 302 IS 2 BP 285 EP 293 DI 10.1006/jmbi.2000.4070 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 355VG UT WOS:000089408800001 PM 10970733 ER PT J AU Shimotakahara, S Gorin, A Kolbanovskiy, A Kettani, A Hingerty, BE Amin, S Broyde, S Geacintov, N Patel, DJ AF Shimotakahara, S Gorin, A Kolbanovskiy, A Kettani, A Hingerty, BE Amin, S Broyde, S Geacintov, N Patel, DJ TI Accomodation of S-cis-tamoxifen-N-2-guanine adduct within a bent and widened DNA minor groove SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE covalent tamoxifen complex; groove binding; localized helical perturbation; widened minor groove ID BREAST-CANCER PATIENTS; ALPHA-HYDROXYTAMOXIFEN; CRYSTAL-STRUCTURES; REVERSE-TRANSCRIPTASE; RAT HEPATOCYTES; DIOL EPOXIDE; TAMOXIFEN; LIVER; POLYMERASE; SULFOTRANSFERASE AB The non-steroidal anti-estrogen tamoxifen [TAM] has been in clinical use over the last two decades as a potent adjunct chemotherapeutic agent for treatment of breast cancer. It has also been given prophylactically to women with a strong family history of breast cancer. However, tamoxifen treatment has also been associated with increased endometrial cancer, possibly resulting from the reaction of metabolically activated tamoxifen derivatives with cellular DNA. Such DNA adducts can be mutagenic and the activities of isomeric adducts may be conformation-dependent. We therefore investigated the high resolution NMR solution conformation of one covalent adduct (cis-isomer, S-epimer of [TAM]G) formed h-om the reaction of tamoxifen [TAM] to N-2-of guanine in the d(C-[TAM]G-C).d(G-C-G) sequence context at the 11-mer oligonucleotide duplex level. Our NMR results establish that the S-cis [TAM]G lesion is accomodated within a widened minor groove without disruption of the Watson-Crick [TAM]G.C and flanking Watson-Crick G.C base-pairs. The helix axis of the bound DNA oligomer is bent by about 30 degrees and is directed away from the minor groove adduct site. The presence of such a bulky [TAM]G adduct with components of the TAM residue on both the 5'- and the 3'-side of the modified base could compromise the fidelity of the minor groove polymerase scanning machinery. (C) 2000 Academic Press. C1 Mem Sloan Kettering Canc Ctr, Cellular Biochem & Biophys Program, New York, NY 10021 USA. NYU, Dept Chem, New York, NY 10003 USA. NYU, Dept Biol, New York, NY 10003 USA. Oak Ridge Natl Lab, Life Sci Res Div, Oak Ridge, TN 37831 USA. Amer Hlth Fdn, Valhalla, NY 10595 USA. RP Patel, DJ (reprint author), Mem Sloan Kettering Canc Ctr, Cellular Biochem & Biophys Program, 1275 York Ave, New York, NY 10021 USA. RI kolbanovskiy, aleksandr/I-7278-2013; Gorin, Andrey/B-1545-2014 FU NCI NIH HHS [CA-75449, CA-20851, CA-46533] NR 56 TC 5 Z9 5 U1 0 U2 1 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 SEP 15 PY 2000 VL 302 IS 2 BP 377 EP 393 PG 17 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 355VG UT WOS:000089408800008 PM 10970740 ER PT J AU Moore, JD Cui, ST Cochran, HD Cummings, PT AF Moore, JD Cui, ST Cochran, HD Cummings, PT TI A molecular dynamics study of a short-chain polyethylene melt. I. Steady-state shear SO JOURNAL OF NON-NEWTONIAN FLUID MECHANICS LA English DT Article DE polyethylene; nonequilibrium molecular dynamics; shear-enhanced diffusion ID SELF-DIFFUSION; BRANCHED ALKANES; RHEOLOGICAL PROPERTIES; POLYMETHYLENE MELTS; LINEAR POLYETHYLENE; ROUSE MODEL; N-ALKANES; SIMULATIONS; EQUILIBRIUM; VISCOSITY AB Utilizing a united atom potential model and reversible reference system propagator algorithm (rRESPA) multi-timestep dynamics, we have performed equilibrium and nonequilibrium molecular dynamics simulations of a monodisperse C100H202 polyethylene melt at 448 K and 0.75 g/cm(3). We report a variety of properties calculated at equilibrium including rotational relaxation time and self-diffusion coefficient as well as shear-enhanced diffusion and rheological properties calculated under steady-state shearing conditions. Shear thinning is observed in the vis cosity and normal stress coefficients over the range of strain rates studied. A minimum in the hydrostatic pressure is observed at an intermediate strain rate that is associated with a minimum in the intermolecular Lennard-Jones potential energy as well as transitions in the strain-rate-dependent behavior of several other viscous and structural properties of the system. The shear field also imposes significant alignment of the chains with the flow direction, approaching a limiting angle of approximately 3 degrees at high strain rate. In addition, the self-diffusion coefficients (calculated in terms of the unconvected positions according to the Cummings-Wang formalism) are markedly enhanced under shear compared to the equilibrium state (up to two orders of magnitude at the highest shear rate studied). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37996 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37996 USA. RP Univ Tennessee, Dept Chem Engn, 419 Dougherty Engn Bldg, Knoxville, TN 37996 USA. EM ptc@utk.edu RI Cummings, Peter/B-8762-2013; Moore, Jonathan/B-8201-2009 OI Cummings, Peter/0000-0002-9766-2216; NR 42 TC 55 Z9 56 U1 0 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0257 EI 1873-2631 J9 J NON-NEWTON FLUID JI J. Non-Newton. Fluid Mech. PD SEP 15 PY 2000 VL 93 IS 1 BP 83 EP 99 DI 10.1016/S0377-0257(00)00103-8 PG 17 WC Mechanics SC Mechanics GA 353WM UT WOS:000089298500005 ER PT J AU Moore, JD Cui, ST Cochran, HD Cummings, PT AF Moore, JD Cui, ST Cochran, HD Cummings, PT TI A molecular dynamics study of a short-chain polyethylene melt. II. Transient response upon onset of shear SO JOURNAL OF NON-NEWTONIAN FLUID MECHANICS LA English DT Article DE polyethylene; nonequilibrium molecular dynamics; stress-overshoot ID SPIN-ECHO SPECTROSCOPY; COX-MERZ RULE; RHEOLOGICAL PROPERTIES; ROUSE MODEL; LINEAR POLYETHYLENE; POLYMETHYLENE MELTS; ENTANGLED POLYMERS; BRANCHED ALKANES; SIMULATIONS; BEHAVIOR AB Using nonequilibrium molecular dynamics simulation, we have studied the response of a C100H202 model polyethylene melt to a step change from equilibrium to a constant, high shear rate flow. The transient shear stress exhibits pronounced overshoot at the strain value predicted by the reptation model, in striking similarity to melts of longer, entangled polymer governed by reptation motion. The Doi-Edwards theory is found to be applicable but only by taking into account the shear-rate-dependence of the terminal relaxation time (which is also consistent with the calculated shear-rate-dependence of the xx component of melt's self-diffusion tensor). We also analyze the molecular origins of stress overshoot behavior in short polymer chains by decomposing the shear stress and normal stress differences into the contributions from various molecular interactions and by examining the shear-induced ordering in the C100H202 melt. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem Engn, Knoxville, TN 37992 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37992 USA. Univ Tennessee, Dept Comp Sci, Knoxville, TN 37992 USA. Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Univ Tennessee, Dept Chem Engn, Knoxville, TN 37992 USA. EM ptc@utk.edu RI Moore, Jonathan/B-8201-2009; Cummings, Peter/B-8762-2013 OI Cummings, Peter/0000-0002-9766-2216 NR 43 TC 17 Z9 17 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0257 EI 1873-2631 J9 J NON-NEWTON FLUID JI J. Non-Newton. Fluid Mech. PD SEP 15 PY 2000 VL 93 IS 1 BP 101 EP 116 DI 10.1016/S0377-0257(00)00104-X PG 16 WC Mechanics SC Mechanics GA 353WM UT WOS:000089298500006 ER PT J AU Kim, MH Londono, JD Habenschuss, A AF Kim, MH Londono, JD Habenschuss, A TI Structure of molten stereoregular polyolefins with different side-chain sizes: Linear polyethylene, polypropylene, poly(1-butene), and poly(4-methyl-1-pentene) SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE polyolefins; X-ray diffraction; polymer melts; structure; polyethylene (PE); isotactic polypropylene (iPP); isotactic poly(1-butene) (iP1B); isotactic poly(4-methyl-1-pentene) (iP4M1P) ID X-RAY-DIFFRACTION; THERMODYNAMICS; BLENDS AB The melt structures of linear polyethylene and the isotactic vinyl polymers polypropylene, poly(1-butene), and poly(4-methyl-1-pentene), along with the corresponding methyl, ethyl, and isobutyl side chains, were studied with wide-angle X-ray diffraction. As the size of the side branch increases from zero (polyethylene) to methyl, ethyl, and isobutyl, a prepeak appears below the main diffraction peak in the total structure factor. The prepeaks become stronger and shift to lower scattering vectors with increasing bulkiness of the side chain. There is a strong correlation between the position of the prepeaks in the melt and the average nearest-neighbor helix-helix packing distance in the crystals, implying similar helical conformations in the melts. (C) 2000 John Wiley & Sons, Inc.* C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Dupont Co, Expt Stn Lab, Wilmington, DE 19880 USA. RP Habenschuss, A (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 15 TC 10 Z9 10 U1 1 U2 5 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD SEP 15 PY 2000 VL 38 IS 18 BP 2480 EP 2485 DI 10.1002/1099-0488(20000915)38:18<2480::AID-POLB150>3.0.CO;2-8 PG 6 WC Polymer Science SC Polymer Science GA 348UE UT WOS:000089004200015 ER PT J AU Urbansky, ET Gu, BH Magnuson, ML Brown, GM Kelty, CA AF Urbansky, ET Gu, BH Magnuson, ML Brown, GM Kelty, CA TI Survey of bottled waters for perchlorate by electrospray ionization mass spectrometry (ESI-MS) and ion chromatography (IC) SO JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE LA English DT Article DE bottled water; perchlorate; ion chromatography; electrospray ionization mass spectrometry; drinking water ID DRINKING-WATER AB Perchlorate has been identified in ground and surface waters around the USA including some that serve as supplies for drinking water. Because perchlorate salts are used as solid oxidants in rockets and ordnance, water contamination may occur near military or aerospace installations or defense industry manufacturing facilities. This ion has been added to the Environmental Protection Agency's Contaminant Candidate List and the Unregulated Contaminant Monitoring Rule. Concern over perchlorate has prompted many residents in affected areas to switch to bottled water; however, bottled waters have not previously been examined for perchlorate contamination. Should the EPA promulgate a regulation for municipal water systems, US law requires the Food and Drug Administration to take action on bottled water. Methods will therefore be required to determine perchlorate concentrations not only in tap water, but also in bottled waters. Ion chromatography (IC) is the primary technique used for its analysis in drinking water, but it does not provide a unique identification. Confirmation by electrospray ionization mass spectrometry (ESI-MS) can serve in this capacity. The ESI-MS method can be applied to these products, but it requires an understanding of matrix effects, especially of high ionic strength that can suppress electrospray. When using methyl isobutyl ketone (MIBK) as the extraction solvent, the ESI-MS method can reach lower limits of detection of 6 ng ml(-1) for some bottled waters. However, dilution required to negate ionic strength effects in mineral waters can raise this by a factor of 10 or more, depending on the sample. Decyltrimethylammonium cation (added as the bromide salt) is used to produce an ion pair that is extracted into MIBK. After extraction, the sum of the peak areas of the ions C10H21NMe3(Br)(ClO4)(-) (m/z = 380) and C10H21NMe3(ClO4)(2)(-) (m/z = 400) is used to quantitate perchlorate. Standard additions are used to account for most of the matrix effects. In this work, eight domestic brands and eight imported brands of bottled water were comparatively analyzed by the two techniques. For comparison, a finished potable water known to contain perchlorate was also tested. None of the bottled waters were found to contain any perchlorate within the lower limit of detection for the IC method. Recoveries on spiked samples subjected to the IC method were greater than or equal to 98%. Published in 2000 for SCI by John Wiley & Sons, Ltd. C1 US EPA, Off Res & Dev, Natl Risk Management Res Lab, Water Supply & Water Resources Div, Cincinnati, OH 45268 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Urbansky, ET (reprint author), US EPA, Off Res & Dev, Natl Risk Management Res Lab, Water Supply & Water Resources Div, Cincinnati, OH 45268 USA. RI Gu, Baohua/B-9511-2012 OI Gu, Baohua/0000-0002-7299-2956 NR 30 TC 25 Z9 26 U1 1 U2 10 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0022-5142 J9 J SCI FOOD AGR JI J. Sci. Food Agric. PD SEP 15 PY 2000 VL 80 IS 12 BP 1798 EP 1804 DI 10.1002/1097-0010(20000915)80:12<1798::AID-JSFA723>3.0.CO;2-J PG 7 WC Agriculture, Multidisciplinary; Chemistry, Applied; Food Science & Technology SC Agriculture; Chemistry; Food Science & Technology GA 349BR UT WOS:000089024400013 ER PT J AU Burton, H AF Burton, H TI Robo sapiens: The evolution of a new species. SO LIBRARY JOURNAL LA English DT Book Review C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Burton, H (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD SEP 15 PY 2000 VL 125 IS 15 BP 110 EP 110 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 353QR UT WOS:000089287400228 ER PT J AU Fenollosa, R You, H Chu, Y Parkhutik, V AF Fenollosa, R You, H Chu, Y Parkhutik, V TI X-ray reflectivity study of formation of multilayer porous anodic oxides of silicon SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT Joint FEMS Symposium/E-MRS Symposium H Strain in Materials: Analysis, Relatation and Properties CY JUN 01-04, 1999 CL STRASBOURG, FRANCE DE electrochemical oscillations; anodic silicon oxide; x-ray reflectivity AB The paper reports data on the kinetics of anodic oxide films growth on silicon in aqueous solutions of phosphoric acids as well as a study of the morphology of the oxides grown in a special regime of the oscillating anodic potential. X-ray reflectivity measurements were performed on the samples of anodic oxides using an intense synchrotron radiation source. They have a multilayer structure as revealed by theoretical fitting of the reflectivity data. The oscillations of the anodic potential are explained in terms of synchronized oxidation/dissolution reactions at the silicon surface and accumulation of mechanical stress in the oxide film. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Politecn Valencia, Dept Termodinam Aplicada, E-46071 Valencia, Spain. Argonne Natl Lab, Argonne, IL 60439 USA. RP Fenollosa, R (reprint author), Univ Politecn Valencia, Dept Termodinam Aplicada, Cami Vera S-N, E-46071 Valencia, Spain. RI Fenollosa, Roberto/M-4499-2014; You, Hoydoo/A-6201-2011 OI Fenollosa, Roberto/0000-0003-2758-9823; You, Hoydoo/0000-0003-2996-9483 NR 8 TC 3 Z9 3 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 SEP 15 PY 2000 VL 288 IS 2 BP 235 EP 238 DI 10.1016/S0921-5093(00)00848-0 PG 4 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 341UG UT WOS:000088607600024 ER PT J AU Orel, AE Schneider, IF Suzor-Weiner, A AF Orel, AE Schneider, IF Suzor-Weiner, A TI Dissociative recombination of H(3)(+): progress in theory SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article; Proceedings Paper CT Discussion Meeting on Astronomy, Physics and Chemistry H-3(plus) CY FEB 09-10, 2000 CL ROYAL SOC LONDON, LONDON, ENGLAND HO ROYAL SOC LONDON DE Rydberg states; interstellar molecules; dissociative recombination; non-adiabatic interactions; predissociation; molecular ion ID LOW-TEMPERATURE; RYDBERG STATES; STORAGE-RING; H-3+; HEH+; PREDISSOCIATION; EXCITATION; SPECTRA; D-3(+); IONS AB Dissociative recombination is the main destruction process for ground-state H(3)(+) in diffuse interstellar medium. Experiments agree on relatively large cross-sections for this reaction. Time-dependent two-dimensional calculations confirm the experimental results at high energy as well as the observed predissociation rates of Hg Rydberg states, due to non-adiabatic interactions. However, the value for low-energy cross-section, deduced from the predissociation rates by an extrapolation procedure, is about four orders of magnitude lower than the measured one. A calculation based on multichannel quantum defect theory suggests that an indirect non-adiabatic process may prevail in this case. The cross-section increases by orders of magnitude compared with the extrapolated value when indirect couplings via apparently ineffective channels are properly considered. We discuss ho iv this channel-mixing mechanism can be effective in the case of H(3)(+), and show encouraging results stressing the role of Rydberg series or 'closed channels'. We also discuss possible three-dimensional effects that could enhance the process at low energy. C1 Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. Natl Inst Lasers Plasma & Radiat Phys, Bucharest, Romania. Univ Paris 11, Photophys Mol Lab, F-91405 Orsay, France. Chim Phys Lab, F-75234 Paris, France. RP Orel, AE (reprint author), Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. NR 32 TC 36 Z9 36 U1 0 U2 1 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD SEP 15 PY 2000 VL 358 IS 1774 BP 2445 EP 2456 PG 12 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 359ZP UT WOS:000089642200012 ER PT J AU Liberman, DA AF Liberman, DA TI Slater transition-state band-structure calculations SO PHYSICAL REVIEW B LA English DT Article ID CORE-HOLE; SEMICONDUCTORS AB Slater's transition-state method enables one to calculate excitation energies by means of an artificial stare that is halfway between the ground state of an atom or molecule and an excited state. This idea has been adapted to insulators and semiconductors with a band-structure model where a localized hole is created in one cell by removing charge from the top of the valence band and putting it in a delocalized state at the bottom of the conduction band. Significant improvements in calculated band gaps are obtained in most cases over conventional local-density calculations. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. EM liberman@west.llnl.gov NR 12 TC 65 Z9 65 U1 1 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 SEP 15 PY 2000 VL 62 IS 11 BP 6851 EP 6853 DI 10.1103/PhysRevB.62.6851 PG 3 WC Physics, Condensed Matter SC Physics GA 355XH UT WOS:000089413500001 ER PT J AU Wei, SH Zhang, SB AF Wei, SH Zhang, SB TI Structure stability and carrier localization in CdX (X = S, Se, Te) semiconductors SO PHYSICAL REVIEW B LA English DT Article ID BAND OFFSETS; D-ORBITALS; II-VI; ZINCBLENDE; ALLOYS AB We studied systematically the structural and electronic properties of binary CdX (X=S, Se, and Te) semiconductors in both zinc-blende (ZB) and wurtzite (WZ) structures, the band alignment on the ZB/WZ interfaces. and carrier localization induced by the band offsets. We show, by first-principles band-structure calculation that at low temperature, CdS is stable in the wurtzite structure, while CdSe and CdTe are stable in the zinc-blende structure. However, coherent substrate strain can change CdTe to be more stable in the wurtzite form. We find that CdX in the wurtzite structure has a larger band gap than the one in the zinc-blende structure. The band alignment on the ZB/WZ interface is found to be type II with holes localized on the wurtzite side and electrons an the zinc-blende side. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Wei, SH (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 22 TC 130 Z9 131 U1 5 U2 38 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 SEP 15 PY 2000 VL 62 IS 11 BP 6944 EP 6947 DI 10.1103/PhysRevB.62.6944 PG 4 WC Physics, Condensed Matter SC Physics GA 355XH UT WOS:000089413500026 ER PT J AU Lange, RJ Fisher, IR Canfield, PC Antropov, VP Lee, SJ Harmon, BN Lynch, DW AF Lange, RJ Fisher, IR Canfield, PC Antropov, VP Lee, SJ Harmon, BN Lynch, DW TI Observation of a metamagnetic phase transition in an itinerant 4f system via the magneto-optic Kerr effect: Ce(Fe1-xCox)(2) SO PHYSICAL REVIEW B LA English DT Article ID X-RAY DICHROISM; INTERMETALLIC COMPOUNDS; ANTIFERROMAGNETIC PHASE; ELECTRONIC-STRUCTURE; CIRCULAR-DICHROISM; ORBITAL MAGNETISM; POLARIZED NEUTRON; RARE-EARTH; CEFE2; RFE2 AB The optical and magneto-optical properties of single crystals of YFe2, CeFe2, and Ce(Fe1-xCox)(2) (x similar or equal to 0.1) were measured between 1.4 and 5.0 eV using a rotating-analyzer ellipsometer and a normal-incidence polar Kerr spectrometer. The electronic structures and optical properties of YFe2 and CeFe2 were calculated using the tight-binding linear muffin-tin orbital method in the atomic-sphere approximation. For YFe2 the calculations reproduce the experimental spectra. Alloying CeFe2 with small amounts of Co leads to an electronic instability which is evidenced by a low-temperature antiferromagnetic (AF) phase. The Kerr effect was measured in the AF and field-induced ferromagnetic (FM) regime. A remarkably large Kerr rotation was measured even in the AF state (up to - 1 degrees). The phase transition from AF to FM order was observed in the Kerr rotation spectra at 5 and 50 K at photon energies of 1.8 and 4.0 eV. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Lange, RJ (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 62 TC 7 Z9 7 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 2000 VL 62 IS 11 BP 7084 EP 7092 DI 10.1103/PhysRevB.62.7084 PG 9 WC Physics, Condensed Matter SC Physics GA 355XH UT WOS:000089413500050 ER PT J AU Jones, ED Allerman, AA Kurtz, SR Modine, NA Bajaj, KK Tozer, SW Wei, X AF Jones, ED Allerman, AA Kurtz, SR Modine, NA Bajaj, KK Tozer, SW Wei, X TI Photoluminescence-linewidth-derived reduced exciton mass for InyGa1-yAs1-xNx alloys SO PHYSICAL REVIEW B LA English DT Article ID WAVELENGTH SEMICONDUCTOR-LASERS; TOTAL-ENERGY CALCULATIONS; BAND-GAP ENERGY; WAVE BASIS-SET; QUANTUM-WELL; PRESSURE-DEPENDENCE; MOLECULAR-DYNAMICS; GAINNAS ALLOYS; DIODES; METALS AB We report the measurement of the variation of the value of the linewidth of an excitonic transition at 4 K in InyGa1-yAs1-xNx alloys (1% and 2% nitrogen) as a function of hydrostatic pressure using photoluminescence spectroscopy. We find that the value of the excitonic Linewidth increases as a function of pressure until about 100 kbar after which it tends to saturate. This change in the excitonic linewidth is used to derive the pressure variation of the exciton reduced mass using a theoretical formalism based on the premise that the broadening of the excitonic transition is caused primarily by compositional fluctuations in a completely disordered alloy. The variation of this derived mass is compared with the results from a nearly first-principles approach in which calculations based on the local-density approximation to the Kohn-Sham density-functional theory are corrected using a small amount of experimental input. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Emory Univ, Dept Phys, Atlanta, GA 30322 USA. Natl High Magnet Field Lab, Tallahassee, FL 32306 USA. RP Jones, ED (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 34 TC 27 Z9 28 U1 0 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 SEP 15 PY 2000 VL 62 IS 11 BP 7144 EP 7149 DI 10.1103/PhysRevB.62.7144 PG 6 WC Physics, Condensed Matter SC Physics GA 355XH UT WOS:000089413500059 ER PT J AU Han, DX Baugh, J Yue, GZ Wang, Q AF Han, DX Baugh, J Yue, GZ Wang, Q TI Light-induced structural changes and their correlation to metastable defect creation in intrinsic hydrogenated amorphous silicon films SO PHYSICAL REVIEW B LA English DT Article ID A-SI-H; MICROCRYSTALLINE SILICON; DILUTION; MODEL AB Device-quality intrinsic a-Si:H films were prepared by three methods, hot-wire (HW) chemical vapor deposition (CVD), and glow-discharge (GD) CVD with and without H dilution, and show varied light-induced metastable defect creation [Staebler-Wronski effect (SWE)]. We found the following: (a) In addition to the nonuniform H distribution, the a-Si network is inhomogeneous, and the film prepared by GD is more homogeneous than the HW film. (b) The light-induced increase of Si-H stretching absorption at similar to 2000 cm(-1) is on the order of 10(-2) in all the films, and an additional decrease at similar to 2025 cm(-1) is found in films with larger SWE. (c) The change of the compressive stress is on the order of 10(-4) of the initial value in the HW films, which is the same order of magnitude as in GD films. Both the initial stress and light-induced volume expansion decrease with decreasing Si-H concentration. No simple correlation between the light-induced structural changes and the conductivity changes was found in the HW a-Si:H films. We describe the light-induced structural changes in conjunction with the creation of metastable defects by a two-phase model. C1 Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Han, DX (reprint author), Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. RI Baugh, Jonathan/F-3879-2011 NR 29 TC 31 Z9 31 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 SEP 15 PY 2000 VL 62 IS 11 BP 7169 EP 7178 DI 10.1103/PhysRevB.62.7169 PG 10 WC Physics, Condensed Matter SC Physics GA 355XH UT WOS:000089413500063 ER PT J AU Boettger, JC AF Boettger, JC TI Approximate two-electron spin-orbit coupling term for density-functional-theory DFT calculations using the Douglas-Kroll-Hess transformation SO PHYSICAL REVIEW B LA English DT Article ID STRUCTURAL PHASE-STABILITY; LINEAR COMBINATION; 2-ELECTRON TERMS; FINE-STRUCTURE; BASIS SET; SYSTEMS; MOLYBDENUM; MOLECULES; FORMALISM; ATOMS AB A simple approximation is developed fbr the two-electron spin orbit coupling terms generated by the Douglas-Kroll-Hess transformation, in the context of density-functional theory (DFT). For the special case of an isolated atom, the two-electron spin-orbit matrix element for each pair of basis functions of type I is replaced with the spin-orbit matrix element for a point charge -Q(l) placed at the origin; where Q(l) = 0,2,10,28,.... Application of this screened-nuclear-spin-orbit (SNSO) approximation to linear combination of Gaussian-type orbital (LCGTO) DFT calculations on Ce, Ta, and Pu atoms yields spin-orbit splittings that agree with results from a numerical solution of the Dirac-Kohn-Sham equations to within about 6%. This is a marked improvement over the nuclear-only spin-orbit approximation, which systematically overestimates spinorbit splittings; in some cases by as much as 100%. Crystalline LCGTO DFT calculations on the fee phases of the light-actinide metals Th --> Pu, using a multiatom generalization of the SNSO approximation, yield atomic volumes that are in excellent agreement with results from full-potential linear-augmented-plane-wave calculations. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Boettger, JC (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 42 TC 55 Z9 55 U1 1 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 2000 VL 62 IS 12 BP 7809 EP 7815 DI 10.1103/PhysRevB.62.7809 PG 7 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400029 ER PT J AU Woods, LM AF Woods, LM TI Electronic structure of Ca2RuO4: A comparison with the electronic structures of other ruthenates SO PHYSICAL REVIEW B LA English DT Article ID SR2RUO4; SUPERCONDUCTIVITY; CRYSTAL AB Density-functional calculations are used to study the electronic and magnetic structures of Ca2RuO4. It is found that the magnetic and structural degrees of freedom are strongly coupled. It is also found that the electronic structure near the Fermi level is described by the antibonding Ru 4d and O 2p bands as is the case for other 4d Ruddlesden-Popper materials. The distortion of the lattice has a pronounced effect on the magnetic ordering and localization of the carriers. The calculations give a good estimate of the magnetic moment and they indicate that there is a magnetic instability in this compound. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Woods, LM (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 16 TC 14 Z9 14 U1 0 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 SEP 15 PY 2000 VL 62 IS 12 BP 7833 EP 7838 DI 10.1103/PhysRevB.62.7833 PG 6 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400032 ER PT J AU Honold, MM Harrison, N Kartsovnik, MV Yaguchi, H Singleton, J Mielke, CH Kushch, ND Kurmoo, M Day, P AF Honold, MM Harrison, N Kartsovnik, MV Yaguchi, H Singleton, J Mielke, CH Kushch, ND Kurmoo, M Day, P TI Mapping of the anomalous magnetotransport regime in the alpha-(BEDT-TTF)(2)MHg(SCN)(4) (M = K, Tl) organic conductors SO PHYSICAL REVIEW B LA English DT Article ID HIGH-FIELD PHASE; TRANSFER SALT ALPHA-(BEDT-TTF)(2)KHG(SCN)(4); CHIRAL SURFACE-STATES; HIGH MAGNETIC-FIELDS; CHARGE-DENSITY-WAVE; MAGNETORESISTANCE OSCILLATIONS; QUANTUM OSCILLATIONS; FERMI SURFACES; EFFECTIVE-MASS; GROUND-STATE AB We present a comprehensive set of pulsed-magnetic-field measurements of the quasi-two-dimensional organic conductors alpha-(BEDT-TTF)(2)MHg(SCN)(4) (M = K, Tl) to map out the boundaries of a high-field regime that was recently associated with the presence of the bulk quantum Hall effect. The phase inversion effect observed in the interplane magnetoresistivity and the behavior of quantum oscillations in the Hall potential are used to investigate the high-field region as a function of magnetic field, temperature, rotation angle, sweep rate, sample quality, and the anion of the charge-transfer salt. The inversion of the phase of the oscillations in rho(zz), is found to be directly related to the quality of the sample, and is suggested to be an intrinsic property of alpha-(BEDT-TTF)(2)MHg(SCN)(4) (M = K, Tl). A detailed mapping of the phase-inverted region indicates that its boundaries agree qualitatively with those of the recently proposed low-temperature-high-field state. C1 Univ Oxford, Dept Phys, Clarendon Lab, Oxford OX1 3PU, England. Los Alamos Natl Lab, Natl High Magnet Field Lab, Los Alamos, NM 87545 USA. Walther Meissner Inst Tieftemp Forsch, D-85748 Garching, Germany. Russian Acad Sci, Inst Chem Phys Res, Chernogolovka 142432, Russia. UCL Royal Inst Great Britain, London W1X 4BS, England. RP Univ Oxford, Dept Phys, Clarendon Lab, Parks Rd, Oxford OX1 3PU, England. RI Kartsovnik, Mark/E-3598-2013; Mielke, Charles/S-6827-2016 OI Kartsovnik, Mark/0000-0002-3011-0169; Mielke, Charles/0000-0002-2096-5411 NR 58 TC 8 Z9 8 U1 0 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 2000 VL 62 IS 12 BP 7908 EP 7919 DI 10.1103/PhysRevB.62.7908 PG 12 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400039 ER PT J AU Kim, HJ Barticevic, Z Ramdas, AK Rodriguez, S Grimsditch, M Anthony, TR AF Kim, HJ Barticevic, Z Ramdas, AK Rodriguez, S Grimsditch, M Anthony, TR TI Zeeman effect of electronic Raman lines of accepters in elemental semiconductors: Boron in blue diamond SO PHYSICAL REVIEW B LA English DT Article ID INFRARED-SPECTRA; SPECTROSCOPY; SCATTERING AB The Zeeman effect of the electronic Raman transition from 1s(p(3/2)):Gamma(8) to the 1s(p(1/2)):Gamma(7) spin-orbit partner (Delta') of boron accepters in diamond is studied with magnetic field B along [001], [111], or [110]. As many as eight Zeeman components of Delta' and, in addition, four Raman lines ascribed to transitions between fhe Zeeman sublevels of Gamma(8) [Raman-electron-paramagnetic-resonance (Raman-EPR) transitions] are observed with the polarizations expected from the polarizability tensors that characterize them. These tensors are formulated in terms of gamma(1), gamma(2), and gamma(3) the Luttinger parameters characterizing the p(3/2) and p(1/2) valence band maxima. The selection rules and relative intensities of the Zeeman components and of the Raman-EPR lines, observed in diverse polarization configurations and scattering geometries, have led to determination of (1) the assignments of magnetic quantum numbers; (2) the level ordering of the Zeeman sublevels, or, equivalently, the magnitudes and signs of g(1) and g(2), the orbital and spin g factors of the acceptor-bound hole; (3) the extreme mass anisotropy as reflected in the ratio (gamma(2)/gamma(3))= 0.08 +/- 0.01 Magnetic-field-induced mixing of zero field states, time reversal symmetry, and the diamagnetic contributions that characterize the different sublevels: are fully taken into account in the interpretation of the experimental results. These include the striking mutual exclusion of the Stokes spectrum from its anti-Stokes counterpart in specific polarization configurations. C1 Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Argonne Natl Lab, Argonne, IL 60439 USA. GE, Corp Res & Dev, Schenectady, NY 12309 USA. RP Kim, HJ (reprint author), Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NR 40 TC 3 Z9 3 U1 2 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 2000 VL 62 IS 12 BP 8038 EP 8052 DI 10.1103/PhysRevB.62.8038 PG 15 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400054 ER PT J AU Lu, ZY Wang, CZ Ho, KM AF Lu, ZY Wang, CZ Ho, KM TI Correlated piecewise diffusion of a Ge ad-dimer on the Si(001) surface SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; SI(100) SURFACE; SI; GROWTH; PSEUDOPOTENTIALS; DYNAMICS AB We have performed extensive first-principles calculations to study the binding and diffusion of a Ge ad-dimer on the Si(001) surface. The diffusion of a Ge ad-dimer along the lowest-energy-barrier pathway is found to be piecewise but with strong correlation, and its energy barrier is 0.77 eV. Such a correlated piecewise diffusion pathway is also found to be favored by a Si ad-dimer on Si(001), with an energy barrier of 1.02 eV in excellent agreement with experimental measurements. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP US DOE, Ames Lab, Ames, IA 50011 USA. RI 上官, 敏慧/E-8964-2012 NR 22 TC 28 Z9 28 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 2000 VL 62 IS 12 BP 8104 EP 8107 DI 10.1103/PhysRevB.62.8104 PG 4 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400064 ER PT J AU Arapaki, E Argyrakis, P Tringides, MC AF Arapaki, E Argyrakis, P Tringides, MC TI Diffusion studies in nonequilibrium systems with attractive interactions SO PHYSICAL REVIEW B LA English DT Article ID SURFACE-DIFFUSION; MONTE-CARLO; ADSORBATE; GROWTH; KINETICS; MODEL AB Diffraction experiments can be used easily to measure the time evolution of a system under nonequilibrium conditions to attain a new equilibrium state and deduce "nonequilibrium'' surface diffusion coefficients. It is not clear how the "nonequilibrium" diffusion coefficients extracted from such diffraction experiments should be interpreted. We study with Monte Carlo simulations the behavior of the "nonequilibrium" tracer and collective diffusion coefficients in a lattice-gas model with attractive nearest-neighbor interactions, as the system evolves in time from an initial random state to attain the (1x1) ordered state for temperatures T/T-c <1. We calculate the dependence of the mean-square displacement [R-2] on time and the collective diffusion from the relaxation of the nonequilibrium structure factor S((q) over right arrow,t) within time sub-intervals under the assumption that quasiequilibrium holds. We determine the time-dependent "nonequilibrium" diffusion coefficients and extract the time-dependent activation energies. For both diffusion coefficients the "nonequilibrium" values obtained at late times are compared to the corresponding values obtained at equilibrium. C1 Univ Thessaloniki, Dept Phys, Thessaloniki 54006, Greece. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RP Arapaki, E (reprint author), Univ Thessaloniki, Dept Phys, Thessaloniki 54006, Greece. NR 14 TC 10 Z9 10 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 SEP 15 PY 2000 VL 62 IS 12 BP 8286 EP 8294 DI 10.1103/PhysRevB.62.8286 PG 9 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400086 ER PT J AU Alfonso, DR Snyder, JA Jaffe, JE Hess, AC Gutowski, M AF Alfonso, DR Snyder, JA Jaffe, JE Hess, AC Gutowski, M TI Opposite rumpling of the MgO and CaO (100) surfaces: A density-functional theory study SO PHYSICAL REVIEW B LA English DT Article ID GENERALIZED GRADIENT APPROXIMATION; INITIO MOLECULAR-DYNAMICS; TOTAL-ENERGY CALCULATIONS; MGO(001) SURFACE; MGO(100) SURFACE; RELAXATION; LEED; TRANSITION; SYSTEMS; OXIDES AB Density-functional theory calculations using the periodic slab approach are carried out to investigate the relaxed structures of the regular MgO and CaO(100) surfaces. Both local density and gradient corrected approximations to the exchange-correlation energy are employed and slab orbitals are expanded in Gaussian atom-centered orbitals as well as in plane waves; For MgO, the cations are displaced downwards towards the bulk relative to the oxygens with surface rumpling of ca. 2%. The vertical displacements of the atoms in CaO are in the opposite direction, producing a rumple of ca. -0.5%. It is suggested that the opposite rumpling is driven by steric effects, i.e., by the larger size of calcium cations relative to magnesium cations. C1 Pacific NW Natl Lab, Div Energy, Richland, WA 99352 USA. Univ Gdansk, Dept Chem, PL-08952 Gdansk, Poland. RP Gutowski, M (reprint author), Pacific NW Natl Lab, Div Energy, Richland, WA 99352 USA. NR 56 TC 29 Z9 29 U1 0 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 SEP 15 PY 2000 VL 62 IS 12 BP 8318 EP 8322 DI 10.1103/PhysRevB.62.8318 PG 5 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400090 ER PT J AU Freitag, A Larese, JZ AF Freitag, A Larese, JZ TI Layer growth of methane on MgO: An adsorption isotherm study SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-SCATTERING; MGO(100); CH4; SURFACES; MOLECULES; DYNAMICS; FILMS; KR; XE; AR AB The layering properties of methane on MgO (100) were measured between 70 K and 96 K using high-resolution adsorption isotherms. The results demonstrate that at least five layers can form. Phase transitions for the different layers were identified by monitoring the changes in the isothermal compressibility of a particular layer as a function of chemical potential. A phase transition (melting) for the monolayer is observed at about 80 K, whereas layers 2 through 4 show a similar transition at about 85 K. The isosteric heat of adsorption was calculated as a function of coverage to gain insight into the growth process of the CH4/MgO system. The thermodynamic quantities determined here are compared with published experimental values. Our data provide key information for defining current methane-MgO interaction potentials. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Freitag, A (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 19 TC 25 Z9 25 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 SEP 15 PY 2000 VL 62 IS 12 BP 8360 EP 8365 DI 10.1103/PhysRevB.62.8360 PG 6 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400094 ER PT J AU Sternemann, C Hamalainen, K Kaprolat, A Soininen, A Doring, G Kao, CC Manninen, S Schulke, W AF Sternemann, C Hamalainen, K Kaprolat, A Soininen, A Doring, G Kao, CC Manninen, S Schulke, W TI Final-state interaction in Compton scattering from electron liquids SO PHYSICAL REVIEW B LA English DT Article ID IMPULSE APPROXIMATION; PERFORMANCE; GAS; LI AB We present Compton profiles (CP's) of Li measured with momentum space resolution of 0.02 a.u. and 8-9 keV incident photon energy. The valence CP's are found to be asymmetric in shape and the predicted sharp features at the Fermi break are drastically smeared out. The observed additional broadening of the CP beyond experimental resolution is predominantly attributed to the finite width of the spectral density function of the excited particle. The asymmetry agrees well with calculations using a many-particle scheme, which will be useful for interpreting final states in soft x-ray and photoemission. C1 Univ Dortmund, Inst Phys, D-44221 Dortmund, Germany. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. RP Sternemann, C (reprint author), Univ Dortmund, Inst Phys, D-44221 Dortmund, Germany. RI Hamalainen, Keijo/A-3986-2010 OI Hamalainen, Keijo/0000-0002-9234-9810 NR 18 TC 21 Z9 21 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 SEP 15 PY 2000 VL 62 IS 12 BP R7687 EP R7690 DI 10.1103/PhysRevB.62.R7687 PG 4 WC Physics, Condensed Matter SC Physics GA 359CF UT WOS:000089593400003 ER PT J AU Bettencourt, LMA Antunes, ND Zurek, WH AF Bettencourt, LMA Antunes, ND Zurek, WH TI Ginzburg regime and its effects on topological defect formation SO PHYSICAL REVIEW D LA English DT Article ID SCALAR FIELD-THEORY; COSMIC STRINGS; PHASE-TRANSITIONS; COSMOLOGICAL EXPERIMENTS; STATISTICAL-MECHANICS; VORTEX FORMATION; SUPERFLUID HE-3; MODEL; THERMODYNAMICS; VORTICES AB The Ginzburg temperature has historically been proposed as the energy scale of formation of topological defects at a second order symmetry breaking phase transition. More recently alternative proposals which compute the time of formation of defects from the critical dynamics of the system have been gaining both theoretical and experimental support. We investigate, using a canonical model for string formation, how these two pictures compare. In particular we shaw that prolonged exposure of a critical field configuration to the Ginzburg regime results in no substantial suppression of the final density of defects formed. These results eliminate the Ginzburg regime as a possible cause of erasure of vortex lines in the recent He-4 pressure quench experiments. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. RP Bettencourt, LMA (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-6, Los Alamos, NM 87545 USA. NR 31 TC 20 Z9 20 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 2000 VL 62 IS 6 AR 065005 DI 10.1103/PhysRevD.62.065005 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 354CB UT WOS:000089311300054 ER PT J AU Huterer, D Turner, MS AF Huterer, D Turner, MS TI Degree of scale invariance of inflationary perturbations SO PHYSICAL REVIEW D LA English DT Article ID COSMIC BACKGROUND-RADIATION; DENSITY PERTURBATIONS; GRAVITATIONAL-WAVES; EXTENDED INFLATION; UNIVERSE; MODELS; FLUCTUATIONS AB Most inflationary models predict that the power-law index of the spectrum of density perturbations is close to 1, though nor precisely equal to 1, \n-1\similar to O(0.1), implying that the spectrum of density perturbations is nearly, but not exactly, scale invariant. However, there are models where it is significantly less than 1 (n similar to 0.7); a spectral index significantly greater than 1 is more difficult to achieve. Without recourse to specific models, we show very generally and very explicitly that n approximate to 1 is a consequence of the slow-roll conditions for inflation and "naturalness," and thus, that near scale invariance is a generic prediction of inflation and a test of the inflationary framework. We derive the conditions needed to deviate significantly from scale invariance, and then show, by explicit construction, the existence of smooth potentials that satisfy all the conditions for successful inflation and give n as large as 2. C1 Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, NASA Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Univ Chicago, Dept Phys, Chicago, IL 60637 USA. NR 35 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 2000 VL 62 IS 6 AR 063503 DI 10.1103/PhysRevD.62.063503 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 354CB UT WOS:000089311300007 ER PT J AU Ioannisian, A Pilaftsis, A AF Ioannisian, A Pilaftsis, A TI Cumulative nondecoupling effects of Kaluza-Klein neutrinos in electroweak processes SO PHYSICAL REVIEW D LA English DT Review ID LARGE EXTRA DIMENSIONS; LARGE INTERNAL DIMENSIONS; LEPTON-FLAVOR VIOLATION; SCALE QUANTUM-GRAVITY; NEUTRAL HEAVY-LEPTONS; MU-E CONVERSION; LARGE COMPACT DIMENSIONS; SPACE-TIME DIMENSIONS; LEFT-RIGHT MODELS; TEV-SCALE AB In Kaluza-Klein theories of low-scale quantum gravity, gravitons and isosinglet neutrinos may propagate in a higher-dimensional space with large compact dimensions, whereas all particles of the standard model are confined on a (1+3)-dimensional subspace. After compactification of the extra dimensions, the resulting Yukawa couplings of the Kaluza-Klein neutrinos to the lepton doublets become naturally very suppressed by a higher-dimensional volume factor, in agreement with phenomenological observations. We show that one-loop effects induced by Kaluza-Klein neutrinos, albeit tiny individually, act cumulatively in electroweak processes, giving rise to a nondecoupling behavior for large values of the higher-dimensional Yukawa couplings. Owing to the nondecoupling effects of Kaluza-Klein neutrinos, we can derive stronger constraints on the parameters of the theory that originate from the nonobservation of Kaluza-violating and universality-breaking phenomena, which involve the W and Z bosons, and the e, mu, and tau leptons. C1 Max Planck Inst Phys, D-80805 Munich, Germany. CERN, Div Theory, CH-1211 Geneva 23, Switzerland. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Thessaloniki, Dept Theoret Phys, GR-54006 Salonika, Greece. RP Ioannisian, A (reprint author), Max Planck Inst Phys, Fohringer Ring 6, D-80805 Munich, Germany. NR 120 TC 61 Z9 61 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 2000 VL 62 IS 6 AR 066001 DI 10.1103/PhysRevD.62.066001 PG 15 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 354CB UT WOS:000089311300062 ER PT J AU New, KCB Centrella, JM Tohline, JE AF New, KCB Centrella, JM Tohline, JE TI Gravitational waves from long-duration simulations of the dynamical bar instability SO PHYSICAL REVIEW D LA English DT Article ID BINARY NEUTRON-STARS; RAPIDLY ROTATING STARS; NONAXISYMMETRIC INSTABILITY; PARTICLE HYDRODYNAMICS; COMPACT BINARIES; STIFF EQUATIONS; RADIATION; POLYTROPES; STABILITY; CODE AB Compact astrophysical objects that rotate rapidly may encounter the dynamical "bar instability." The bar-like deformation induced by this rotational instability causes the object to become a potentially strong source of gravitational radiation. We have carried out a set of long-duration simulations of the bar instability with two Eulerian hydrodynamics codes. Our results indicate that the remnant of this instability is a persistent bar-like structure that emits a long-lived gravitational radiation signal. C1 Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. RP Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 64 TC 44 Z9 44 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD SEP 15 PY 2000 VL 62 IS 6 AR 064019 DI 10.1103/PhysRevD.62.064019 PG 16 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 354CB UT WOS:000089311300038 ER PT J AU Malkowski, MG Ginell, SL Smith, WL Garavito, RM AF Malkowski, MG Ginell, SL Smith, WL Garavito, RM TI The productive conformation of arachidonic acid bound to prostaglandin synthase SO SCIENCE LA English DT Article ID CYCLOOXYGENASE ACTIVE-SITE; ENDOPEROXIDE-H SYNTHASE-1; NONSTEROIDAL ANTIINFLAMMATORY DRUGS; HUMAN COLON-CANCER; CRYSTAL-STRUCTURE; H-2 SYNTHASE; ASPIRIN; INHIBITION; BINDING; COX-2 AB Prostaglandin H synthase-1 and -2 (PGHS-1 and -2) catalyze the committed step in prostaglandin synthesis and are targets for nonsteroidal anti-inflammatory drugs (NSAIDs) Like aspirin. We have determined the structure of PGHS-1 at 3 angstrom resolution with arachidonic acid (AA) bound in a chemically productive conformation. The fatty acid adopts an extended L-shaped conformation that positions the 13proS hydrogen of AA for abstraction by tyrosine-385, the Likely radical donor. A space also exists for oxygen addition on the antarafacial surface of the carbon in the 11-position (C-11). While this conformation allows endoperoxide formation between C-11 and C-9, it also implies that a subsequent conformational rearrangement must occur to allow formation of the C-8/C-12 bond and to position C-15 for attack by a second molecule of oxygen. C1 Michigan State Univ, Dept Biochem & Mol Biol, E Lansing, MI 48824 USA. Argonne Natl Lab, Struct Biol Ctr, Argonne, IL 60439 USA. RP Garavito, RM (reprint author), Michigan State Univ, Dept Biochem & Mol Biol, E Lansing, MI 48824 USA. RI Malkowski, Michael/G-4939-2011 OI Malkowski, Michael/0000-0003-1025-0014 FU NHLBI NIH HHS [F32 HL10170-01, R01 HL56773]; NIGMS NIH HHS [P01 GM57323] NR 40 TC 200 Z9 203 U1 4 U2 18 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 SEP 15 PY 2000 VL 289 IS 5486 BP 1933 EP 1937 DI 10.1126/science.289.5486.1933 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 354XD UT WOS:000089355800046 PM 10988074 ER PT J AU Campbell, GH Belak, J Moriarty, JA AF Campbell, GH Belak, J Moriarty, JA TI Atomic structure of the Sigma 5 (310)/[001] symmetric tilt grain boundary in tantalum SO SCRIPTA MATERIALIA LA English DT Article DE transmission electron microscopy; grain boundaries; theory and modeling of defects ID BCC TRANSITION-METALS; TRANSMISSION ELECTRON-MICROSCOPY; INTERATOMIC POTENTIALS; ANGULAR FORCES; MOLYBDENUM; SIMULATION; MO C1 Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA USA. RP Campbell, GH (reprint author), Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. RI Campbell, Geoffrey/F-7681-2010 NR 23 TC 20 Z9 20 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD SEP 15 PY 2000 VL 43 IS 7 BP 659 EP 664 DI 10.1016/S1359-6462(00)00475-9 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 356PD UT WOS:000089450900013 ER PT J AU Gelman, A Price, PN Lin, C AF Gelman, A Price, PN Lin, C TI A method for quantifying artefacts in mapping methods illustrated by application to headbanging SO STATISTICS IN MEDICINE LA English DT Article ID MAPS AB Maps of disease rates (and other quantities) often must contend with variance associated with variable population sizes and low incidence within spatial units. These characteristics can lead to substantial statistical noise that can mask underlying spatial variation. As Gelman and Price illustrated, most conventional mapping methods fail to address this problem, and in fact can introduce statistical artefacts; mapped quantities can show spatial patterns even when there are no spatial patterns in the underlying parameter of interest. Kafadar evaluated the performance of the headbanging algorithm for spatial smoothing (Tukey and Tukey, Hansen) for eliminating small scale variation and preserving edge structure. Here we perform a simulation study to investigate the artefacts of maps smoothed by unweighted and weighted headbanging. We find substantial artefacts that depend on the spatial structure of the statistical Variation (for example, the spatial pattern of sample sizes) and on the details of the spatial distribution of geographic units. The methods used here could readily be adapted to study other spatial smoothers; we choose headbanging because (i) it is an important method used in practice, and (ii) its heavily computational nature is naturally studied using simulation (in contrast to the analytical methods used by Gelman and Price). Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Columbia Univ, Dept Stat, New York, NY 10027 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Energy & Environm, Berkeley, CA 94720 USA. RP Gelman, A (reprint author), Columbia Univ, Dept Stat, New York, NY 10027 USA. NR 7 TC 6 Z9 6 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0277-6715 J9 STAT MED JI Stat. Med. PD SEP 15 PY 2000 VL 19 IS 17-18 BP 2309 EP 2320 DI 10.1002/1097-0258(20000915/30)19:17/18<2309::AID-SIM571>3.0.CO;2-H PG 12 WC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Medicine, Research & Experimental; Statistics & Probability SC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Research & Experimental Medicine; Mathematics GA 353LE UT WOS:000089275000009 PM 10960855 ER PT J AU Bender, F Cernosek, RW Josse, F AF Bender, F Cernosek, RW Josse, F TI Love-wave biosensors using cross-linked polymer waveguides on LiTaO3 substrates SO ELECTRONICS LETTERS LA English DT Article AB The design and performance of Love-wave sensors using cross-linked poly(methyl methacrylate) waveguides of thicknesses of 0.3 to 3.2 mu m on LiTaO3 substrates are described. It is found that this laver-substrate combination provides sufficient waveguidance and electrical isolation of the interdigital transducers from the liquid environment to achieve low acoustic loss and distortion. In biosensing experiments, mass sensitivity up to 1420Hz/(ng/mm(2)) is demonstrated. C1 Sandia Natl Labs, Microsensor Res & Dev Dept, Albuquerque, NM 87185 USA. Marquette Univ, Microsensor Res Lab, Milwaukee, WI 53201 USA. Marquette Univ, Dept Elect & Comp Engn, Milwaukee, WI 53201 USA. RP Bender, F (reprint author), Sandia Natl Labs, Microsensor Res & Dev Dept, POB 5800, Albuquerque, NM 87185 USA. NR 6 TC 31 Z9 34 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD SEP 14 PY 2000 VL 36 IS 19 BP 1672 EP 1673 DI 10.1049/el:20001137 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 361KH UT WOS:000089721900050 ER PT J AU Zavaliy, IY Yelon, WB Zavalij, PY Saldan, IV Pecharsky, VK AF Zavaliy, IY Yelon, WB Zavalij, PY Saldan, IV Pecharsky, VK TI The crystal structure of the oxygen-stabilized eta-phase Zr3V3OxD9.6 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE hydrogen storage materials; crystal structure; X-ray powder diffraction; neutron powder diffraction ID DEUTERIUM SITE OCCUPATION; HYDROGEN ABSORPTION; CARBIDES ZR3V3ODX; ZR-V; ALLOYS; FE AB Hydrogen storage capacity and crystal structure of hydrogen-free Zr3V3O0.6 and its saturated deuteride, Zr3V3OxD9.6, and have been studied using both X-ray and neutron powder diffraction. Experimental data together with the geometrical analysis of the crystal structure of the deuteride indicate that oxygen non-stoichiometry plays a significant role in the 2-fold increase of hydrogen storage capacity of Zr3V3O0.6 compared with the stoichiometric oxygenated Zr3V3O. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Natl Acad Sci Ukraine, Phys Mech Inst, UA-290601 Lviv, Ukraine. Univ Missouri, Res Reactor, Columbia, MO 65211 USA. SUNY Binghamton, Mat Res Ctr, Binghamton, NY 13902 USA. RP Pecharsky, VK (reprint author), Iowa State Univ, Ames Lab, 242A Spedding, Ames, IA 50011 USA. RI Zavalij, Peter/H-3817-2012 OI Zavalij, Peter/0000-0001-5762-3469 NR 19 TC 12 Z9 13 U1 0 U2 1 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 SEP 14 PY 2000 VL 309 IS 1-2 BP 75 EP 82 DI 10.1016/S0925-8388(00)00899-9 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 356HW UT WOS:000089438700016 ER PT J AU Liu, J Shin, Y Nie, ZM Chang, JH Wang, LQ Fryxell, GE Samuels, WD Exarhos, GJ AF Liu, J Shin, Y Nie, ZM Chang, JH Wang, LQ Fryxell, GE Samuels, WD Exarhos, GJ TI Molecular assembly in ordered mesoporosity: A new class of highly functional nanoscale materials SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID AMINO-GROUPS; SILICA; SIEVES; FILMS; MONOLAYERS; OXIDE; GEL; CATALYSIS; COPOLYMER; TEMPLATE AB Assembly of organized molecular structures in ordered mesoporosity has shown to be a very powerful approach to synthesize novel functional nanoscale materials. This approach allows rational design of a wide range of material properties, such as pore dimension, surface chemistry, stereochemistry, spatial distribution of functionality, etc. This paper discusses molecular conformations and assembly mechanisms and illustrates the principles involved in fabricating sophisticated molecular structures in the pore channels. First, an introduction highlights the important progress in synthesizing and understanding ordered mesoporous materials and in incorporating functional molecules and groups in these mesoporous materials. Next, the molecular conformations of simple alkyl chains are discussed as related to chain lengths and pore geometry. The pore size, as well as the uniformity of the porosity, can affect how the long-chain molecules are assembled. Homogeneous molecular layers can be formed in 10 nm pores. Smaller pore sizes cause pore clogging and chain entanglement. Larger pore sizes increase the degree of pore irregularity and produce disordered multilayer coating. Molecules with intermediate chain lengths form better molecular layer structures. Detailed mechanisms of monolayer formation are studied, and a stepwise growth model is proposed. The step-growth mechanism is due to the surface roughness of the pore channels and is believed to be universal in forming "monolayers" involving surfaces that are not atomically smooth. Finally, the development of multifunctional nanoporous materials is described. Examples include multifunctionalized catalysts, hierarchical size-and-shape selective nanoporous materials with tunable micropatterns and microcavities. The assembly of multifunctional groups and structures will allow us to develop sophisticated nanoscale materials with "enzyme mimic" and "biomimic" properties. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Liu, J (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. NR 81 TC 128 Z9 129 U1 3 U2 32 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 SEP 14 PY 2000 VL 104 IS 36 BP 8328 EP 8339 DI 10.1021/jp0009812 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 353HC UT WOS:000089267900002 ER PT J AU Glass, GP Kumaran, SS Michael, JV AF Glass, GP Kumaran, SS Michael, JV TI Photolysis of ketene at 193 nm and the rate constant for H+HCCOat 297 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID FLASH KINETIC SPECTROSCOPY; LYING ELECTRONIC STATES; AB-INITIO CALCULATIONS; PRESSURE-DEPENDENCE; BRANCHING RATIO; TEMPERATURE; RECOMBINATION; REMOVAL; CH; PHOTODISSOCIATION AB The 193 nm photolysis of ketene was studied by measuring the amount of atomic hydrogen produced when very dilute ketene/Ar and ketene/H-2 mixtures were irradiated by a single pulse from an ArF excimer laser. Absolute concentrations of atomic hydrogen were monitored over a time interval of 0-2.5 ms by using Lyman-alpha atomic resonance absorption spectroscopy (ARAS). Four different photodissociation channels of ketene were identified: H2CCO + hz, gives (a) CH2(B-3(1)) + CO; (b) CH2((1)A(1)) + CO; (c) HCCO + H; and (d) C2O(b(1)Sigma(+)) + H-2. The quantum yields for each channel were measured as phi(a) = 0.628, phi(b) = 0.193, phi(c) = 0.107, and phi(d) = 0.072, respectively. To explore the secondary chemistry that occurred when using higher pressure H2CCO/Ar mixtures, a mechanism was constructed that used well-documented reactions and, for most processes, rate constants that had already been accurately determined. Modeling studies using this mechanism showed the [H] profile to be determined largely by the rate of the reaction I;I + HCCO --> CH2 + CO. An excellent fit to all of the experimental data was obtained when k(2) = (1.7 +/- 0.3) x 10(-10) cm(3) molecule(-1) s(-1). C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Rice Univ, Dept Chem, Houston, TX 77251 USA. RP Michael, JV (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Michael, Joe/E-3907-2010 NR 58 TC 29 Z9 29 U1 3 U2 11 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 SEP 14 PY 2000 VL 104 IS 36 BP 8360 EP 8367 DI 10.1021/jp000782i PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 353HC UT WOS:000089267900006 ER PT J AU Saravanan, C Salazar, MR Kress, JD Redondo, A AF Saravanan, C Salazar, MR Kress, JD Redondo, A TI Oxametallacycle intermediates on clean and Cs-promoted Ag(111) surfaces SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SELECTIVE ETHYLENE OXIDATION; EFFECTIVE CORE POTENTIALS; MOLECULAR CALCULATIONS; CATALYTIC-OXIDATION; CORRELATION-ENERGY; SUBSURFACE OXYGEN; SINGLE-CRYSTAL; EPOXIDATION; DENSITY; SILVER AB We have performed density functional theory calculations for a model cluster representative of the [111] face of Ag to study the effect of Cs and Cs+ on a proposed oxametallacycle intermediate of ethylene epoxidation. A systematic study of the binding energies of O, Cs, and Cs+ on the symmetry sites of the Ag(111) surface was performed by varying the basis sets and cluster sizes. We find that ethylene binds to an oxygen atom on an Ag cluster to make a bound -O-C2H4 species. In the presence of Cs or Cs+, we find a bound oxametallocycle. In both Cs-promoted cases, this oxametallocycle is, within the errors of our calculations, isoenergetic with respect to the desorption of ethylene with the O atom remaining bound to the promoted Ag cluster. Atomic charge calculations were performed revealing that Ca is an electron donor for the oxametallacycle without actually being a part of the ring. In fact, we find that the presence of the electron-donating Cs atom repels the oxametallacycle intermediate. C1 Los Alamos Natl Lab, Div Theoret, Grp T12, Los Alamos, NM 87545 USA. Univ Massachusetts, Dept Chem, Amherst, MA 01003 USA. RP Los Alamos Natl Lab, Div Theoret, Grp T12, Los Alamos, NM 87545 USA. EM salazarm@lanl.gov NR 50 TC 17 Z9 17 U1 1 U2 3 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 SEP 14 PY 2000 VL 104 IS 36 BP 8685 EP 8691 DI 10.1021/jp001030r PG 7 WC Chemistry, Physical SC Chemistry GA 353HD UT WOS:000089268000008 ER PT J AU Rubin, EM Tall, A AF Rubin, EM Tall, A TI Perspectives for vascular genomics SO NATURE LA English DT Article ID BINDING CASSETTE TRANSPORTER-1; TANGIER-DISEASE; CARDIOVASCULAR DEVELOPMENT; HEMATOPOIETIC LINEAGES; INSULIN-RESISTANCE; APOLIPOPROTEIN-E; DEFICIENT MICE; GENE-PRODUCT; ATHEROSCLEROSIS; ZEBRAFISH AB Diseases of the vascular system result from a complex mixture of genetic and environmental factors. Data sets, technologies and strategies emanating from the human genome programme have been applied to the analysis of both rare single-gene and common multigenic vascular disorders. Genomic approaches including inter- and intraspecies sequence comparisons, genotyping with dense marker sets spanning the genome, large-scale mutagenesis screens of model organisms, and genome-wide expression profiling have all begun to contribute to the identification of new genes and mechanisms that are central to cardiovascular disease processes. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Genome Sci Dept, Berkeley, CA 94720 USA. Columbia Univ Coll Phys & Surg, Dept Med, Div Mol Med, New York, NY 10032 USA. RP Rubin, EM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Genome Sci Dept, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 43 TC 31 Z9 32 U1 1 U2 4 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD SEP 14 PY 2000 VL 407 IS 6801 BP 265 EP 269 DI 10.1038/35025236 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 352VX UT WOS:000089241000063 PM 11001070 ER PT J AU Fang, XW Littrell, K Yang, X Henderson, SJ Siefert, S Thiyagarajan, P Pan, T Sosnick, TR AF Fang, XW Littrell, K Yang, X Henderson, SJ Siefert, S Thiyagarajan, P Pan, T Sosnick, TR TI Mg2+-dependent compaction and folding of yeast tRNA(Phe) and the catalytic domain of the B-subtilis RNase P RNA determined by small-angle X-ray scattering SO BIOCHEMISTRY LA English DT Article ID SECONDARY STRUCTURE; ESCHERICHIA-COLI; DENATURED STATES; LARGE RIBOZYME; KINETIC TRAPS; PROTEINS; ACID AB We apply synchrotron-based small-angle X-ray scattering to investigate the relationship between compaction, metal binding, and structure formation of two RNAs at 37 degrees C: the 76 nucleotide yeast tRNA(Phe) and the 255 nucleotide catalytic domain of the Bacillus subtilis RNase P RNA. For both RNAs, this method provides direct evidence for the population of a distinct folding intermediate. The relative compaction between the intermediate and the native state does not correlate with the size of the RNA but does correlate well with the amount of surface burial as quantified previously by the urea-dependent m-value. The total compaction process can be described in two major stages. Starting from a completely unfolded state (4-8 M urea, no Mg2+), the major amount of compaction occurs upon the dilution of the denaturant and the addition of micromolar amounts of Mg2+ to form the intermediate. The native state forms in a single transition from the intermediate state upon cooperative binding of three to four Mg2+ ions. The characterization of this intermediate by small-angle X-ray scattering lends strong support for the cooperative Mg2+-binding model to describe the stability of a tertiary RNA. C1 Univ Chicago, Dept Biochem & Mol Biol, Chicago, IL 60637 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Sosnick, TR (reprint author), Univ Chicago, Dept Biochem & Mol Biol, 920 E 58th St, Chicago, IL 60637 USA. RI ID, BioCAT/D-2459-2012; Littrell, Kenneth/D-2106-2013 OI Littrell, Kenneth/0000-0003-2308-8618 FU NCRR NIH HHS [RR08630]; NIGMS NIH HHS [R01GM57880] NR 38 TC 94 Z9 99 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 12 PY 2000 VL 39 IS 36 BP 11107 EP 11113 DI 10.1021/bi000724n PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 353RX UT WOS:000089290200020 PM 10998249 ER PT J AU Nieto, MM Truax, DR AF Nieto, MM Truax, DR TI Coherent states sometimes look like squeezed states and vice versa: the Paul trap SO NEW JOURNAL OF PHYSICS LA English DT Article ID ISOMORPHIC SYMMETRY ALGEBRAS; DEPENDENT SCHRODINGER-EQUATIONS; SYSTEMS AB Using the Paul trap as a model, we point out that the same wavefunctions can be variously coherent or squeezed states, depending upon the system to which they are applied. C1 Los Alamos Natl Lab, Theoret Div MSB285, Los Alamos, NM 87545 USA. Univ Ulm, Abt Quantenphys, D-89069 Ulm, Germany. Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada. RP Nieto, MM (reprint author), Los Alamos Natl Lab, Theoret Div MSB285, POB 1663, Los Alamos, NM 87545 USA. EM mmn@lanl.gov; truax@ucalgary.ca NR 22 TC 15 Z9 15 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1367-2630 J9 NEW J PHYS JI New J. Phys. PD SEP 12 PY 2000 VL 2 BP 181 EP 189 AR 18 DI 10.1088/1367-2630/2/1/318 PG 9 WC Physics, Multidisciplinary SC Physics GA 417PH UT WOS:000167843000001 ER PT J AU Henstrom, WL Liu, CP Gibson, JM Kamins, TI Williams, RS AF Henstrom, WL Liu, CP Gibson, JM Kamins, TI Williams, RS TI Dome-to-pyramid shape transition in Ge/Si islands due to strain relaxation by interdiffusion SO APPLIED PHYSICS LETTERS LA English DT Article ID SI(001) AB Ge islands were grown on Si(001) and then annealed at 650 degrees C for 0, 20, 40, and 60 min in a chemical-vapor deposition reactor following Ge deposition. This letter confirms the previous observations directly. By combining the ability to quantify strain with the ability to measure island dimensions in a transmission electron microscope, we were able to plot strain versus aspect ratio for the various annealing times. The islands first relax strain because of Si intermixing with the Ge epilayer causes the lattice mismatch to be lowered. Once the mismatch is sufficiently reduced, and thus the strain energy sufficiently reduced, it becomes favorable for the islands to reverse their shape back from domes to pyramids, thus reducing surface energy. This confirms the reversibility of island shape and thus the thermodynamics of the transition. (C) 2000 American Institute of Physics. [S0003-6951(00)03037-0]. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Hewlett Packard Labs, Palo Alto, CA 94304 USA. RP Liu, CP (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Williams, R. Stanley/A-8281-2009; Liu, Chuan-Pu /H-8926-2012; Gibson, Murray/E-5855-2013 OI Williams, R. Stanley/0000-0003-0213-4259; Gibson, Murray/0000-0002-0807-6224 NR 11 TC 33 Z9 33 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 SEP 11 PY 2000 VL 77 IS 11 BP 1623 EP 1625 DI 10.1063/1.1309027 PG 3 WC Physics, Applied SC Physics GA 351QY UT WOS:000089170700019 ER PT J AU Munkholm, A Thompson, C Murty, MVR Eastman, JA Auciello, O Stephenson, GB Fini, P DenBaars, SP Speck, JS AF Munkholm, A Thompson, C Murty, MVR Eastman, JA Auciello, O Stephenson, GB Fini, P DenBaars, SP Speck, JS TI Layer-by-layer growth of GaN induced by silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID X-RAY-SCATTERING; CHEMICAL-VAPOR-DEPOSITION; SURFACE-STRUCTURE; MORPHOLOGY; AG(111); AG AB We present in situ x-ray scattering studies of surface morphology evolution during metal-organic chemical vapor deposition of GaN. Dosing the GaN(0001) surface with Si is shown to change the growth mode from step-flow to layer-by-layer over a wide temperature range. Annealing of highly doped layers causes Si to segregate to the surface, which also induces layer-by-layer growth. (C) 2000 American Institute of Physics. [S0003-6951(00)02637-1]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. RP Munkholm, A (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Eastman, Jeffrey/E-4380-2011; Speck, James/H-5646-2011; OI Eastman, Jeff/0000-0002-0847-4265; Thompson, Carol/0000-0003-3832-4855 NR 18 TC 29 Z9 29 U1 1 U2 8 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 SEP 11 PY 2000 VL 77 IS 11 BP 1626 EP 1628 DI 10.1063/1.1309023 PG 3 WC Physics, Applied SC Physics GA 351QY UT WOS:000089170700020 ER PT J AU Fowlkes, JD Pedraza, AJ Lowndes, DH AF Fowlkes, JD Pedraza, AJ Lowndes, DH TI Microstructural evolution of laser-exposed silicon targets in SF6 atmospheres SO APPLIED PHYSICS LETTERS LA English DT Article AB The microstructures formed at the surface of silicon during pulsed-laser irradiation in SF6-rich atmospheres consist of an array of microholes surrounded by microcones. It is shown that there is a dynamic interplay between the formation of microholes and microcones. Fluorine produced by the laser-induced decomposition of SF6 is most likely responsible for the etching/ablation process. It is proposed that silicon-rich molecules and clusters that form in and are ejected from the continually deepening microholes sustain the axial and lateral growth of the microcones. The laser-melted layer at the tip and sides of the cones efficiently collects the silicon-rich products formed upon ablation. The total and partial pressures of SF6 in the chamber play a major role in cone development, a clear indication that it is the laser-generated plasma that controls the growth of these cones. (C) 2000 American Institute of Physics. [S0003-6951(00)01637-5]. C1 Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. EM apedraza@utk.edu NR 15 TC 45 Z9 49 U1 0 U2 2 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 SEP 11 PY 2000 VL 77 IS 11 BP 1629 EP 1631 AR PII [S0003-6951(00)01637-5] DI 10.1063/1.1308538 PG 3 WC Physics, Applied SC Physics GA 351QY UT WOS:000089170700021 ER PT J AU Chambers, SA Liang, Y Yu, Z Droopad, R Ramdani, J Eisenbeiser, K AF Chambers, SA Liang, Y Yu, Z Droopad, R Ramdani, J Eisenbeiser, K TI Band discontinuities at epitaxial SrTiO3/Si(001) heterojunctions SO APPLIED PHYSICS LETTERS LA English DT Article ID RAY PHOTOELECTRON-SPECTROSCOPY; PRECISE DETERMINATION AB We have used photoemission methods to directly measure the valence and conduction band offsets at SrTiO3/Si(001) interfaces, as prepared by molecular-beam epitaxy. Within experimental error, the measured values are the same for growth on n- and p-Si, with the entire band discontinuity occurring at the valence band edge. In addition, band bending is much larger at the p-Si heterojunction than at the n-type heterojunction. Previously published threshold voltage behavior for these interfaces can now be understood in light of the present results. (C) 2000 American Institute of Physics. [S0003-6951(00)05337-7]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Motorola Labs, Phys Sci Res Labs, Tempe, AZ USA. RP Chambers, SA (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. NR 9 TC 148 Z9 150 U1 6 U2 30 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 SEP 11 PY 2000 VL 77 IS 11 BP 1662 EP 1664 AR PII [S0003-6951(00)05337-7] DI 10.1063/1.1310209 PG 3 WC Physics, Applied SC Physics GA 351QY UT WOS:000089170700032 ER PT J AU Fishman, RS AF Fishman, RS TI Spin diffusion in the double-exchange model at intermediate temperatures SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID MAGNETS AB Using a combined numerical and analytic approach, we evaluate the spin-diffusion coefficient D for the double-exchange model in the limit t << T << J(H), where t is the hopping energy, T is the temperature, and JH is the Hund's coupling. To lowest order, D proportional to tq(1 - 2q)/T chi where q is given in terms of the band filling p by either p (p < 1/2) or 1 - p (p > 1/2). Hence, the spin-diffusion coefficient vanishes when the electrons are unable to hop between singly-occupied sites ina half-filled (p = 1/2) band. C1 Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RI Fishman, Randy/C-8639-2013 NR 18 TC 4 Z9 4 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 EI 1361-648X J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD SEP 11 PY 2000 VL 12 IS 36 BP L575 EP L581 DI 10.1088/0953-8984/12/36/101 PG 7 WC Physics, Condensed Matter SC Physics GA 356ZU UT WOS:000089474700001 ER PT J AU Yang, C Fukui, K Sumpter, BG Noid, DW Tuzun, RE AF Yang, C Fukui, K Sumpter, BG Noid, DW Tuzun, RE TI Calculating the density of states for large-scale molecular systems SO MACROMOLECULAR THEORY AND SIMULATIONS LA English DT Article ID ALGORITHM; DYNAMICS AB We present a new method for calculating the density of states of large-scale molecular systems. The new algorithm does not require calculation of all eigenvalues of the force constant matrix. The histogram for the eigenvalue distribution is constructed by performing a sequence of sparse LDLT matrix factorizations. Moreover, the entire calculation can be fully parallelized on a multi-processor computer system. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Comp Sci & Math Div, Oak Ridge, TN 37831 USA. SUNY Coll Brockport, Computat Sci Program, Brockport, NY 14420 USA. RP Noid, DW (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RI Sumpter, Bobby/C-9459-2013 OI Sumpter, Bobby/0000-0001-6341-0355 NR 26 TC 1 Z9 1 U1 1 U2 3 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 1022-1344 J9 MACROMOL THEOR SIMUL JI Macromol. Theory Simul. PD SEP 11 PY 2000 VL 9 IS 7 BP 428 EP 432 DI 10.1002/1521-3919(20000801)9:7<428::AID-MATS428>3.0.CO;2-# PG 5 WC Polymer Science SC Polymer Science GA 356UM UT WOS:000089461300007 ER PT J AU Schertler, K Greiner, C Schaffner-Bielich, J Thoma, MH AF Schertler, K Greiner, C Schaffner-Bielich, J Thoma, MH TI Quark phases in neutron stars and a third family of compact stars as signature for phase transitions SO NUCLEAR PHYSICS A LA English DT Article DE quark matter; neutron stars; third family ID HEAVY-ION COLLISIONS; STRANGE MATTER; KAON CONDENSATION; HYBRID STARS; MASSES; MODEL; EQUATION; STATE; RADIUS; OSCILLATIONS AB The appearance of quark phases in the dense interior of neutron stars provides one possibility to soften the equation of state (EOS) of neutron star matter at high densities. This softening leads to more compact equilibrium configurations of neutron stars compared to pure hadronic stars of the same mass. We investigate the question to which amount the compactness of a neutron star can be attributed to the presence of a quark phase. For this purpose we employ several hadronic EOS in the framework of the relativistic mean-field (RMF) model and an extended MIT bag model to describe the quark phase. We find that - almost independent of the model parameters - the radius of a pure hadronic neutron star gets typically reduced by 20-30% if a pure quark phase in the center of the star does exist. For some EOS we furthermore find the possibility of a third family of compact stars which may exist besides the two known families of white dwarfs and neutron stars. We show how an experimental proof of the existence of a third family by mass and radius measurements may provide a unique signature for a phase transition inside neutron stars. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Brookhaven Natl Lab, RIKEN, BNL Res Ctr, Upton, NY 11973 USA. CERN, Div Theory, CH-1211 Geneva 23, Switzerland. RP Schertler, K (reprint author), Univ Giessen, Inst Theoret Phys, D-35392 Giessen, Germany. NR 73 TC 100 Z9 102 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD SEP 11 PY 2000 VL 677 BP 463 EP 490 DI 10.1016/S0375-9474(00)00305-5 PG 28 WC Physics, Nuclear SC Physics GA 348VB UT WOS:000089006200017 ER PT J AU Adler, S Atiya, MS Chiang, IH Diwan, MV Frank, JS Haggerty, JS Kettell, SH Kycia, TF Li, KK Littenberg, LS Sambamurti, A Stevens, A Strand, RC Witzig, C Komatsubara, TK Kuriki, M Muramatsu, N Sugimoto, S Inagaki, T Kabe, S Kobayashi, M Kuno, Y Sato, T Shinkawa, T Yoshimura, Y Kishi, Y Nakano, T Ardebili, M Convery, MR Ito, MM Marlow, DR McPherson, RA Meyers, PD Shoemaker, FC Smith, AJS Stone, JR Aoki, M Blackmore, EW Bergbusch, PC Bryman, DA Konaka, A Macdonald, JA Mildenberger, J Numao, T Padley, P Poutissou, JM Poutissou, R Redlinger, G Kitching, P Soluk, R AF Adler, S Atiya, MS Chiang, IH Diwan, MV Frank, JS Haggerty, JS Kettell, SH Kycia, TF Li, KK Littenberg, LS Sambamurti, A Stevens, A Strand, RC Witzig, C Komatsubara, TK Kuriki, M Muramatsu, N Sugimoto, S Inagaki, T Kabe, S Kobayashi, M Kuno, Y Sato, T Shinkawa, T Yoshimura, Y Kishi, Y Nakano, T Ardebili, M Convery, MR Ito, MM Marlow, DR McPherson, RA Meyers, PD Shoemaker, FC Smith, AJS Stone, JR Aoki, M Blackmore, EW Bergbusch, PC Bryman, DA Konaka, A Macdonald, JA Mildenberger, J Numao, T Padley, P Poutissou, JM Poutissou, R Redlinger, G Kitching, P Soluk, R CA E787 Collaboration TI Measurement of structure-dependent K+ -> mu(+)nu(mu)gamma decay SO PHYSICAL REVIEW LETTERS LA English DT Article ID K+->MU(+)NU-GAMMA DECAY; MUON POLARIZATION; VIOLATION AB We report the first measurement of a structure-dependent component in the decay K+ --> mu(+)nu(mu)gamma. Using the kinematic region where the muon kinetic energy is greater than 137 MeV and the photon energy is greater than 90 MeV, we find that the absolute value of the sum of the vector and axial-vector form factors is [F-V + F-A] = 0.165 +/- 0.007 +/- 0.011. This corresponds to a branching ratio of B(SD+) = (1.33 +/- 0.12 +/- 0.18) x 10(-5). We also set the limit -0.04 ( F-V - F-A < 0.24 at 90% C.L. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. KEK, High Energy Acccelerator Res Org, Tanashi, Tokyo 1888501, Japan. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Osaka Univ, RCNP, Ibaraki, 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. RI Marlow, Daniel/C-9132-2014 NR 22 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 11 PY 2000 VL 85 IS 11 BP 2256 EP 2259 DI 10.1103/PhysRevLett.85.2256 PG 4 WC Physics, Multidisciplinary SC Physics GA 351RA UT WOS:000089170900009 ER PT J AU Guo, CL AF Guo, CL TI Multielectron effects on single-electron strong field ionization SO PHYSICAL REVIEW LETTERS LA English DT Article ID MULTIPHOTON IONIZATION; THRESHOLD IONIZATION; MOLECULES; HELIUM; LASER; ATOMS AB An apparently simple phenomenon of single-electron strong field ionization involves subtle factors related to multielectron effects. A single electron in an atom or molecule can feel a distinctly different screening strength when exposed to strong fields as opposed to weak fields, and this electron screening due to multielectron motion influences single-electron ionization. The concept and a corresponding model developed in the paper allow a generalization of the Ammosov-Delone-Krainov model for predicting strong field ionization rates of more complicated atoms and molecules. This general approach explains the recently observed anomalous low single ionization rate in O-2. C1 Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Guo, CL (reprint author), Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, Condensed Matter & Thermal Phys Grp, POB 1663, Los Alamos, NM 87545 USA. NR 22 TC 67 Z9 67 U1 3 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 11 PY 2000 VL 85 IS 11 BP 2276 EP 2279 DI 10.1103/PhysRevLett.85.2276 PG 4 WC Physics, Multidisciplinary SC Physics GA 351RA UT WOS:000089170900014 ER PT J AU Reichhardt, C Gronbech-Jensen, N AF Reichhardt, C Gronbech-Jensen, N TI Collective multivortex states in periodic arrays of traps SO PHYSICAL REVIEW LETTERS LA English DT Article ID MESOSCOPIC SUPERCONDUCTING DISKS; THIN-FILMS; LOGARITHMIC INTERACTIONS; PHASE-TRANSITIONS; PINNING CENTERS; ANTIDOT LATTICE; VORTEX LATTICE; REGULAR ARRAY; MAGNETIC DOTS; VORTICES AB We examine the vortex states in a 2D superconductor interacting with a square array of pinning sites. As a function of increasing pinning size or strength we find a series of novel phases including multivortex and composite superlattice states such as aligned dimer and trimer configurations at individual pinning sites. Interactions of the vortices give rise to an orientational ordering of the internal vortex structures in each pinning site. We also show that these vortex states can give rise to a multistage melting behavior. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC, Berkeley, CA 94720 USA. RP Reichhardt, C (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. OI Reichhardt, Cynthia/0000-0002-3487-5089 NR 32 TC 47 Z9 47 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 11 PY 2000 VL 85 IS 11 BP 2372 EP 2375 DI 10.1103/PhysRevLett.85.2372 PG 4 WC Physics, Multidisciplinary SC Physics GA 351RA UT WOS:000089170900038 ER PT J AU Bicknell, GV Sutherland, RS Van Breugel, WJM Dopita, MA Dey, A Miley, GK AF Bicknell, GV Sutherland, RS Van Breugel, WJM Dopita, MA Dey, A Miley, GK TI Jet-induced emission-line nebulosity and star formation in the high-redshift radio galaxy 4C 41.17 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (4C 41.17); galaxies : ISM; galaxies : jets; galaxies : structure; stars : formation ID REGIONS; SHOCKS; CLOUDS; LIGHT AB The high-redshift radio galaxy 4C 41.17 has been shown in earlier work to consist of a powerful radio source in which there is strong evidence for jet-induced star formation along the radio axis. We argue that nuclear photoionization is not responsible for the excitation of the emission line clouds, and we construct a jet-cloud interaction model to explain the major features revealed by the detailed radio, optical,: and spectroscopic data of 4C 41.17. The interaction of a high-powered (similar to 10(46) ergs s(-1)) jet with a dense:cloud in the halo of 4C 41.17 produces shock-excited emission-line nebulosity through similar to 1000 km: s(-1) shocks and induces star formation. The C rv luminosity emanating from the shock implies that the; preshock density in the line-emitting cloud is high enough (hydrogen density similar to 1-10 cm(-3)) that shock-initiated star formation could proceed on a timescale (similar to a few x 10(6) yr) well within the estimated dynamical age (similar to 3 x 10(7) yr) of the radio source. Broad (FWHM approximate to 1100-1400 km s(-1)) emission lines are attributed to the disturbance of the gas cloud by a partial bow shock, and narrow emission lines (FWHM approximate to 500-650 km s(-1); in particular, C rv lambda lambda 1548, 1550) arise in precursor emission in relatively low-metallicity gas or in shocked line emission in the lateral regions of the bow shock. The implied baryonic mass similar to 8 x 10(10) M-circle dot of the cloud is high and implies that Milky Way size condensations existed in the environments of forming radio galaxies at a redshift of 3.8. Our interpretation of the data provides a physical basis for the alignment of the radio, emission-line, and UV continuum images in some of the highest redshift radio galaxies, and the analysis presented here may form a basis for the calculation of densities and cloud masses in other high-redshift radio galaxies. C1 Australian Natl Univ, Mt Stromlo Observ, Res Sch Astron & Astrophys, ANU Astrophys Theory Ctr, Weston, ACT 2611, Australia. Univ Calif Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. NOAO, KPNO, Tucson, AZ 85726 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. RP Bicknell, GV (reprint author), Australian Natl Univ, Mt Stromlo Observ, Res Sch Astron & Astrophys, ANU Astrophys Theory Ctr, Weston, ACT 2611, Australia. RI Dopita, Michael/P-5413-2014 OI Dopita, Michael/0000-0003-0922-4986 NR 42 TC 105 Z9 105 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 2000 VL 540 IS 2 BP 678 EP 686 DI 10.1086/309343 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360DH UT WOS:000089650800006 ER PT J AU Yanny, B Newberg, HJ Kent, S Laurent-Muehleisen, SA Pier, JR Richards, GT Stoughton, C Anderson, JE Annis, J Brinkmann, J Chen, B Csabai, I Doi, M Fukugita, M Hennessy, GS Ivezic, Z Knapp, GR Lupton, R Munn, JA Nash, T Rockosi, CM Schneider, DP Smith, JA York, DG AF Yanny, B Newberg, HJ Kent, S Laurent-Muehleisen, SA Pier, JR Richards, GT Stoughton, C Anderson, JE Annis, J Brinkmann, J Chen, B Csabai, I Doi, M Fukugita, M Hennessy, GS Ivezic, Z Knapp, GR Lupton, R Munn, JA Nash, T Rockosi, CM Schneider, DP Smith, JA York, DG TI Identification of A-colored stars and structure in the halo of the milky way from Sloan Digital Sky Survey commissioning data SO ASTROPHYSICAL JOURNAL LA English DT Article DE blue stragglers; Galaxy : halo; Galaxy : structure; stars : early-type; stars : horizontal-branch ID HORIZONTAL-BRANCH STARS; GLOBULAR-CLUSTER SYSTEM; GALACTIC STELLAR HALO; RR-LYRAE STARS; BLUE STRAGGLERS; DWARF GALAXY; SOLAR CIRCLE; SDSS FILTERS; FIELD STARS; HOT STARS AB A sample of 4208 objects with magnitude 15 < g* < 22 and colors of main-sequence A stars have been selected from 370 deg(2) of Sloan Digital Sky Survey (SDSS) commissioning observations. The data is from two long, narrow stripes, each with an opening angle of greater than 60 degrees, at Galactic latitudes 36 degrees < \b\ < 63 degrees on the celestial equator. Relative photometric calibrations good to 2% and consistent absolute photometry allows this uniform sample to be treated statistically over the large area. An examination of the sample's distribution shows that these stars trace considerable substructure in the halo. Large overdensities of A-colored stars in the north at (l, b, R) = (350 degrees, 50 degrees, 46 kpc) and in the south at (157, -58, 33 kpc) and extending over tens of degrees are present in the halo of the Milky Way. Ivezic ct al. have detected the northern structure from a sample of RR Lyrae stars in the SDSS. Using photometry to separate the stars by surface gravity, both structures are shown to contain a sequence of low surface gravity stars consistent with identification as a blue horizontal branch (BHB). Both structures also contain a population of high surface gravity stars 2 mag fainter than the BHB stars, consistent with their identification as blue stragglers (BSs). The majority of the high surface gravity stars in the Galactic halo may be BS stars like these. A population of F stars associated with the A star excess in the southern structure is detected (the F stars in the northern structure at 46 kpc would be too faint for the SDSS to detect). From the numbers of detected BHB stars, lower limits to the implied mass of the structures are 6 x 10(6) M(circle dot) and 2 x 10(6) M(circle dot), although one does not yet know the full spatial extent of the structures. The fact that two such large clumps have been detected in a survey of only 1% of the sky indicates that such structures are not uncommon in the halo. Simple spheroidal parameters are fit to a complete sample of the remaining unclumped BHB stars and yield (at r < 40 kpc) a fit to a halo distribution with flattening (c/a = 0.65 +/- 0.2) and a density falloff exponent of alpha = -3.2 +/- 0.3. C1 Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY 12180 USA. LLNL, IGPP, Livermore, CA 94550 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. Univ Chicago, Ctr Astron & Astrophys, Chicago, IL 60637 USA. Apache Point Observ, Sunspot, NM 88349 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Eotvos Lorand Univ, Dept Phys Complex Syst, H-1117 Budapest, Hungary. Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. Univ Tokyo, Sch Sci, Res Ctr Early Universe, Bunkyo Ku, Tokyo 1130033, Japan. RP Yanny, B (reprint author), Fermilab Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. RI Csabai, Istvan/F-2455-2012; OI Csabai, Istvan/0000-0001-9232-9898 NR 48 TC 273 Z9 279 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD SEP 10 PY 2000 VL 540 IS 2 BP 825 EP 841 DI 10.1086/309386 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 360DH UT WOS:000089650800019 ER PT J AU Freitag, LA Plassmann, P AF Freitag, LA Plassmann, P TI Local optimization-based simplicial mesh untangling and improvement SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Unstructured Mesh Generation in conjuction with the 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO DE mesh untangling; mesh improvement; simplicial mesh quality; mesh smoothing ID TRANSFORMATIONS; TRIANGULATIONS; GENERATION AB We present an optimization-based approach for mesh untangling that maximizes the minimum area or volume of simplicial elements in a local submesh. These functions are linear with respect to the free vertex position; thus the problem can be formulated as a linear program that is solved by using the computationally inexpensive simplex method. We prove that the function level sets are convex regardless of the position of the free vertex, and hence the local subproblem is guaranteed to converge. Maximizing the minimum area or volume of mesh elements, although well suited for mesh untangling, is not ideal for mesh improvement, and its use often results in poor quality meshes. We therefore combine the mesh untangling technique with optimization-based mesh improvement techniques and expand previous results to show that a commonly used two-dimensional mesh quality criterion can be guaranteed to converge when starting with a valid mesh. Typical results showing the effectiveness of the combined untangling and smoothing techniques are given for both two- and three-dimensional simplicial meshes. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. Penn State Univ, Dept Comp Sci & Engn, University Pk, PA 16802 USA. RP Freitag, LA (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 24 TC 92 Z9 99 U1 0 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD SEP 10 PY 2000 VL 49 IS 1-2 BP 109 EP 125 DI 10.1002/1097-0207(20000910/20)49:1/2<109::AID-NME925>3.3.CO;2-L PG 17 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 344MX UT WOS:000088764400008 ER PT J AU White, DR Tautges, TJ AF White, DR Tautges, TJ TI Automatic scheme selection for toolkit hex meshing SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Unstructured Mesh Generation in conjuction with the 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO DE cubit; mapping; submapping; sweeping; hexahedra; toolkit AB Current hexahedral mesh generation techniques rely on a set of meshing tools, which when combined with geometry decomposition leads to an adequate mesh generation process. Of these tools, sweeping tends to be the workhorse algorithm, accounting for at least 50 per cent of most meshing applications. Constraints which must be met for a Volume to be sweepable are derived, and it is proven that these constraints are necessary but not sufficient conditions for sweepability. This paper also describes a new algorithm for detecting extruded or sweepable geometries. This algorithm, based on these constraints, uses topological and local geometric information, and is more robust than feature recognition-based algorithms. A method for computing sweep dependencies in volume assemblies is also given. The auto sweep detect and sweep grouping algorithms have been used to reduce interactive user time required to generate all-hexahedral meshes by filtering out non-sweepable volumes needing further decomposition and by allowing concurrent meshing of independent sweep groups. Parts of the auto sweep detect algorithm have also been used to identify independent sweep paths, for use in volume-based interval assignment. Published in 2000 by John Wiley & Sons, Ltd. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Tautges, TJ (reprint author), 1500 Johnson Dr, Madison, WI 53706 USA. NR 22 TC 35 Z9 38 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD SEP 10 PY 2000 VL 49 IS 1-2 BP 127 EP 144 DI 10.1002/1097-0207(20000910/20)49:1/2<127::AID-NME926>3.0.CO;2-V PG 18 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 344MX UT WOS:000088764400009 ER PT J AU Garimella, RV Shephard, MS AF Garimella, RV Shephard, MS TI Boundary layer mesh generation for viscous flow simulations SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Unstructured Mesh Generation in conjuction with the 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO DE anisotropic mesh generation; boundary layer meshes; viscous flow simulations ID DELAUNAY TRIANGULATION; GRID GENERATION AB Viscous flow problems exhibit boundary layers and free shear layers in which the solution gradients, normal and tangential to the flow, differ by orders of magnitude. The generalized advancing layers method is presented here as a method of generating meshes suitable for capturing such flows. The method includes several new technical advances allowing it to mesh complex geometric domains that cannot be handled by other techniques. It is currently being used for simulations in the automotive industry. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Rensselaer Polytech Inst, Sci Computat Res Ctr, Troy, NY 12180 USA. RP Garimella, RV (reprint author), Univ Calif Los Alamos Natl Lab, EES-5,MS C306, Los Alamos, NM 87545 USA. NR 33 TC 40 Z9 43 U1 1 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD SEP 10 PY 2000 VL 49 IS 1-2 BP 193 EP 218 DI 10.1002/1097-0207(20000910/20)49:1/2<193::AID-NME929>3.0.CO;2-R PG 26 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 344MX UT WOS:000088764400012 ER PT J AU Lai, MW Benzley, S White, D AF Lai, MW Benzley, S White, D TI Automated hexahedral mesh generation by generalized multiple source to multiple target sweeping SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Unstructured Mesh Generation in conjuction with the 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO DE meshing; hexahedron; sweeping; boolean AB This paper presents an enhanced sweeping mesh generation algorithm. Traditional sweeping techniques create all hexahedral element meshes by projecting an existing single-surface mesh along a specified trajectory to a specified single target surface. The work reported here enhances the traditional method by creating all hexahedral element meshes between multiple source surfaces and multiple target surfaces. The new algorithm is based on an innovated application of Boolean operations. The core of this process is the rebuilding of the boundary representations of source surfaces by Boolean operations between the boundary loops of both target and source to incorporate a virtual geometry decomposition. Published in 2000. by John Wiley & Sons, Ltd. C1 Brigham Young Univ, Dept Civil & Environm Engn, Provo, UT USA. Sandia Natl Labs, Parallel Comp Sci Dept, Albuquerque, NM 87145 USA. RP Benzley, S (reprint author), Brigham Young Univ, Dept Civil & Environm Engn, Provo, UT USA. NR 27 TC 21 Z9 24 U1 2 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD SEP 10 PY 2000 VL 49 IS 1-2 BP 261 EP 275 DI 10.1002/1097-0207(20000910/20)49:1/2<261::AID-NME932>3.0.CO;2-G PG 15 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 344MX UT WOS:000088764400015 ER PT J AU Shepherd, J Benzley, S Mitchell, S AF Shepherd, J Benzley, S Mitchell, S TI Interval assignment for volumes with holes SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Unstructured Mesh Generation in conjuction with the 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO DE meshing; hexahedron; sweeping; linear program; interval assignment ID MESH AB This paper presents a new technique for automatically detecting interval constraints for swept volumes with holes. The technique finds true volume constraints that are not necessarily imposed by the surfaces of the volume. A graphing algorithm finds independent, parallel paths of edges from source surfaces to target surfaces. The number of intervals on two paths between a given source and target surface must be equal; in general, the collection of paths determine a set of linear constraints. Linear programming techniques solve the interval assignment problem for the surface and volume constraints simultaneously. Published in 2000 by John Wiley & Sons, Ltd. C1 Sandia Natl Labs, Paraellel Comp Sci Dept, Albuquerque, NM 87185 USA. Brigham Young Univ, Dept Civil & Environm Engn, Provo, UT 84604 USA. RP Shepherd, J (reprint author), Sandia Natl Labs, Paraellel Comp Sci Dept, POB 5800, Albuquerque, NM 87185 USA. NR 18 TC 5 Z9 5 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD SEP 10 PY 2000 VL 49 IS 1-2 BP 277 EP 288 PG 12 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 344MX UT WOS:000088764400016 ER PT J AU Owen, SJ Saigal, S AF Owen, SJ Saigal, S TI H-Morph: an indirect approach to advancing front hex meshing SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Unstructured Mesh Generation in conjuction with the 5th US National Congress on Computational Mechanics CY AUG 04-06, 1999 CL UNIV COLORADO, BOULDER, COLORADO HO UNIV COLORADO DE mesh generation; hexahedron; hex-dominant; advancing front ID MEDIAL SURFACE SUBDIVISION; ELEMENT MESHES; GENERATION; ALGORITHM; BOUNDARY; SOLIDS; EDGES AB H-Morph is a new automatic algorithm for the generation of a hexahedral-dominant finite element mesh for arbitrary volumes. The H-Morph method starts with an initial tetrahedral mesh and systematically transforms and combines tetrahedra into hexahedra. It uses an advancing front technique where the initial front consists of a set of prescribed quadrilateral surface facets. Fronts are individually processed by recovering each of the six quadrilateral faces of a hexahedron from the tetrahedral mesh. Recovery techniques similar to those used in boundary constrained Delaunay mesh generation are used. Tetrahedra internal to the six hexahedral faces are then removed and a hexahedron is formed. At any time during the H-Morph procedure a valid mixed hexahedral-tetrahedral mesh is in existence within the volume. The procedure continues until no tetrahedra remain within the volume, or tetrahedra remain which cannot be transformed or combined into valid hexahedral elements. Any remaining tetrahedra are typically towards the interior of the volume, generally a less critical region for analysis. Transition from tetrahedra to hexahedra in the final mesh is accomplished through pyramid-shaped elements. Advantages of the proposed method include its ability to conform to an existing quadrilateral surface mesh, its ability to mesh without the need to decompose or recognize special classes of geometry, and its characteristic well-aligned layers of elements parallel to the boundary. Example test cases are presented on a variety of models. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Sandia Natl Labs, Parallel Comp Sci, Albuquerque, NM 87185 USA. Carnegie Mellon Univ, Dept Civil & Environm Engn, Pittsburgh, PA 15213 USA. RP Owen, SJ (reprint author), Sandia Natl Labs, Parallel Comp Sci, Box 5800,MS 0847, Albuquerque, NM 87185 USA. NR 38 TC 44 Z9 46 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD SEP 10 PY 2000 VL 49 IS 1-2 BP 289 EP 312 DI 10.1002/1097-0207(20000910/20)49:1/2<289::AID-NME934>3.0.CO;2-L PG 24 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 344MX UT WOS:000088764400017 ER PT J AU Rice, MJ Chakraborty, AK Bell, AT AF Rice, MJ Chakraborty, AK Bell, AT TI Site availability and competitive siting of divalent metal cations in ZSM-5 SO JOURNAL OF CATALYSIS LA English DT Article AB Accommodation of divalent cations (M2+) and dimer cations ([MOM](2+)) in zeolites requires the presence of two charge-exchange sites in close proximity to each other. Since each charge-exchange site is associated with a framework Al atom, this constraint requires that 2 Al atoms be located in next-nearest-neighbor T sites. The maximum number of divalent cations that can be accommodated by ZSM-5 as either Z-M(2)(+)Z(-) or Z(-)[MOM](2+)Z(-) (where Z(-) represents a cation-exchange site in the zeolite) has been calculated for a given value of Si/Al, and the results are reported as the maximum value of M/Al. Two cases for the distribution of framework Al atoms are considered: random placement in T sites and placement governed by equilibrium thermodynamics. For both M2+ and [MOM](2+) the maximum value of M/Al is significantly less than 0.5 and 1.0, respectively, because of the required constraints on the Al-Al pairs, and decreases as the Si/Al ratio increases. For M2+ cations the distribution of specific cations (Co2+, Cu2+, Fe2+, Ni2+, Pd2+, Pt2+, and Zn2+) was determined using energies predicted from electronic structure calculations. M2+ cations are preferentially situated in rings containing either five or six T atoms. The manner in which the Al atoms are distributed among T sites affects the distribution of M2+ cations among different types of rings. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Rice, MJ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. OI Bell, Alexis/0000-0002-5738-4645 NR 11 TC 55 Z9 55 U1 0 U2 14 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD SEP 10 PY 2000 VL 194 IS 2 BP 278 EP 285 DI 10.1006/jcat.2000.2977 PG 8 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 355NE UT WOS:000089391100011 ER PT J AU Male, JL Niessen, HG Bell, AT Tilley, TD AF Male, JL Niessen, HG Bell, AT Tilley, TD TI Thermolytic molecular precursor route to active and selective vanadia-zirconia catalysts for the oxidative dehydrogenation of propane SO JOURNAL OF CATALYSIS LA English DT Article DE molecular precursors; alkoxides; vanadia; zirconia; oxidative dehydrogenation ID OXIDE CATALYSTS; TETRAGONAL ZRO2; SILICA XEROGELS; SURFACE-AREA; METAL-OXIDES; V-51 NMR; COMPLEXES; RAMAN; SUPPORTS; ALKANES AB The thermolytic molecular precursor route was employed in attempts to obtain highly dispersed and structurally well-defined vanadia-zirconia catalysts for the oxidative dehydrogenation of propane. The vanadia-zirconia materials were prepared by cothermolysis of OV((OBu)-Bu-t)(3) and Zr(OCMe2Et)(4) in a nonpolar solvent, at relatively low temperatures. Prior to calcination, these materials have relatively high surface areas, are amorphous, and appear to be highly dispersed. After calcination to 773 K, nanocrystalline zirconia and various VOx species, which appear to be dispersed on the zirconia surface, can be observed by PXRD and Raman, DR-UV-vis, and V-51 NMR spectroscopies. Higher vanadia loadings and/or an increased calcination temperature (823 K) resulted in formation of ZrV2O7 (as demonstrated by Raman, DR-UV-vis, and 51V NMR spectroscopies). In general, the VOx/ZrO2 materials obtained from the molecular precursor method possess a greater surface area and exhibit a higher dispersion of VOx species than materials of the same composition prepared by conventional impregnation methods. For catalysts derived from the alkoxides, the maximum rate for propane oxidative dehydrogenation is more than double that observed for VOx/ZrO2 materials prepared by impregnation, under similar conditions. Likewise, higher selectivities to propene (by more than 15%) were observed with materials derived from the alkoxides. However, analysis of the rate data for the new catalysts revealed that the active sites were also more active in catalyzing the secondary oxidation of propene. As a result of this, the ratio of secondary combustion to oxidative dehydrogenation rate constants (k(3)/k(1)) was similar for materials prepared by either wet impregnation or thermolysis of molecular precursors. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Bell, AT (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. OI Bell, Alexis/0000-0002-5738-4645 NR 48 TC 42 Z9 44 U1 2 U2 15 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD SEP 10 PY 2000 VL 194 IS 2 BP 431 EP 444 DI 10.1006/jcat.2000.2938 PG 14 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 355NE UT WOS:000089391100027 ER PT J AU Karasaki, K Freifeld, B Cohen, A Grossenbacher, K Cook, P Vasco, D AF Karasaki, K Freifeld, B Cohen, A Grossenbacher, K Cook, P Vasco, D TI A multidisciplinary fractured rock characterization study at Raymond field site, Raymond, CA SO JOURNAL OF HYDROLOGY LA English DT Article DE fracture; tiltmeter; tracer; transport; tomography ID TRACER TESTS; TRANSPORT; ATTENUATION; INVERSION; FLOW AB A dedicated field site was developed and a suite of experiments were conducted in the Sierra Nevada foothills, near the town of Raymond, CA to develop and test a multi-disciplinary approach to the characterization of groundwater flow and transport in fractured rocks. A wealth of geologic, hydrologic and geophysical data was collected at the site using a variety of unique tools. A cluster of nine approximately 90 m deep boreholes were drilled at the site in a V-shaped pattern with an angle of 60 degrees, The boreholes are spaced 7.5, 15, 30 and 60 m from the central borehole. Various geophysical and hydrologic tests were conducted in and between these boreholes. Integration of cross-hole radar and seismic tomography, borehole flow surveys and images from a new digital borehole scanner indicated that groundwater flow is mainly confined to a few sub-horizontal fracture zones. A unique suite of hydraulic tests were conducted, in which three to four intervals in each of the nine boreholes were isolated using pneumatic packers. Some 130 injection tests were conducted, and more than 4100 cross-hole transient pressure measurements were obtained. A computer algorithm was developed to analyze such massive interference data systematically. As a result of the analysis, an image of the fracture connections emerged, which is consistent with the geophysical data. High precision tiltmeters were effective in remotely characterizing the preferential flow path. Several radial convergent tracer tests were conducted by injecting a mixture of several conservative tracers and one sorbing tracer: deuterium, fluorescein, lithium bromide and polystyrene micro-spheres. Some differences between the breakthrough curves are observed, which may be due to possible differences among so-called "conservative" tracers. Some characterization tools were found to be more effective than others in locating flowing fractures. However, no single tool was almighty. Characterization of fractured rock is extremely challenging and requires a stepwise and well-thought approach, which is basically a good old scientific approach. Prediction of transport based on the characterization results is even more challenging and one should always bear in mind that it is virtually impossible to uniquely characterize a fractured rock. (C) 2000 Published by Elsevier Science B.V. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Financial Engines, Palo Alto, CA 94303 USA. RP Karasaki, K (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. RI Freifeld, Barry/F-3173-2010; Vasco, Donald/I-3167-2016 OI Vasco, Donald/0000-0003-1210-8628 NR 43 TC 59 Z9 59 U1 2 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD SEP 10 PY 2000 VL 236 IS 1-2 BP 17 EP 34 DI 10.1016/S0022-1694(00)00272-9 PG 18 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 356GK UT WOS:000089435400002 ER PT J AU Stokes, DL Vo-Dinh, T AF Stokes, DL Vo-Dinh, T TI Development of an integrated single-fiber SERS sensor SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE SERS sensor; Raman spectroscopy; dip and dry ID ENHANCED RAMAN-SCATTERING; SILVER ELECTRODE; PROBE DESIGNS; ISLAND FILMS; SPECTROSCOPY; SPECTROMETRY; SURFACES; SPECTRA AB An integrated fiberoptic surface-enhanced Raman scattering (SERS) sensor based on a single-fiber system is described and evaluated for remote and in situ measurements. The heart of the sensor consists of a unique single optical fiber designed to induce the SERS effect through the incorporation of alumina nanoparticles and silver coatings onto the probe tip. The unique design based on single-fiber for excitation/emission (SFEE) is practical for the fabrication of in situ sensors in microenvironments. Since the single fiber carries both the laser excitation and SERS signal radiation, optical parameters of the remote tip are simple and consistent. Depending on the tip size, the fiberoptic SERS sensor allows in situ measurements at microscale environments. Details of sensor tip Fabrication and optical system design are described. Two detection schemes can be used: a "dip-and-dry" mode of detection and an in situ sensing mode are demonstrated for several compounds, including cresyl fast violet (CFV), brilliant cresyl blue (BCB), p-aminobenzoic acid (PABA) and 3-aminopyrene (3AP). To illustrate the effectiveness of this new SERS sensor for remote in situ analysis, SERS spectra of aqueous dye samples (CFV and BCB) are presented. A quantitative calibration curve for CFV in groundwater is established and a limit of optical detection of approximately 50 ppb CFV in groundwater is determined. Published by Elsevier Science S.A. C1 Oak Ridge Natl Lab, Div Life Sci, Adv Monitoring Dev Grp, Oak Ridge, TN 37831 USA. RP Vo-Dinh, T (reprint author), Oak Ridge Natl Lab, Div Life Sci, Adv Monitoring Dev Grp, POB 2008, Oak Ridge, TN 37831 USA. NR 38 TC 122 Z9 126 U1 7 U2 63 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD SEP 10 PY 2000 VL 69 IS 1-2 BP 28 EP 36 DI 10.1016/S0925-4005(00)00291-4 PG 9 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 355XX UT WOS:000089414800005 ER PT J AU Meriaudeau, F Wig, A Passian, A Downey, T Buncick, M Ferrell, TL AF Meriaudeau, F Wig, A Passian, A Downey, T Buncick, M Ferrell, TL TI Gold island fiber optic sensor for refractive index sensing SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE gold island fiber optic sensor; refractive index; surface plasmon excitation ID SURFACE-PLASMON RESONANCE; DNA HYBRIDIZATION; FILMS AB A fiber optic chemical sensor based on gold island surface plasmon excitation is presented. The sensing part of the fiber is the end of the fiber onto which a thin layer of gold has been deposited to form a particulate surface. Annealing the gold reshapes the particles and produces an optical absorbance near 535 nm with the fiber in air. The optical absorption resonance of the gold particles is shifted if the fiber is immersed in a medium other than air. These resonance shifts are examined by transmission spectroscopy through the fiber. Experimental results for the sensitivity and dynamic range in the measurement of liquid solutions are in agreement with a basic theoretical model that characterizes the surface plasmon using nonretarded electrodynamics. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Div Life Sci, Photometr Grp, Oak Ridge, TN 37830 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ Memphis, Dept Phys, Memphis, TN 38152 USA. RP Meriaudeau, F (reprint author), LE2I,12 Rue Fonderie, F-71200 Le Creusot, France. NR 16 TC 45 Z9 46 U1 3 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD SEP 10 PY 2000 VL 69 IS 1-2 BP 51 EP 57 DI 10.1016/S0925-4005(00)00406-8 PG 7 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 355XX UT WOS:000089414800008 ER PT J AU Li, DQ Ma, M AF Li, DQ Ma, M TI Surface acoustic wave microsensors based on cyclodextrin coatings SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE surface acoustic wave; cyclodextrin; microsensor ID VAPOR SENSORS; GAS SENSORS; DEVICES; CHEMISTRY; RESPONSES; FILM AB Cyclodextrin thin films were applied to surface acoustic wave (SAW) devices as receptors for detecting organic vapors. Self-assembled monolayers (SAMs) and sol-gel techniques were used in fabricating chemical sensing layer thin films on SAW microsensors. The cyclodextrin coatings on the surface of SAW resonators (200 MHz) were studied as a method of tracking organic toxins in gas phase. The mass loading of cyclodextrin coatings on SAW resonators gave frequency shifts corresponding to a coverage of a typical monolayer for SAM method and "multilayer" for sol-gel techniques. Subsequent exposure of the coated SAW resonators to organic vapors at various concentrations, typically 5000 parts per million (ppm) down to 50 parts per billion (ppb) by mole, gave responses indicating middle-ppb-sensitivity (similar to 50 ppb) for those sensor-host receptors and organic-toxin pairs with optimum mutual matching of polarity, size, or structural properties. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST 4, Los Alamos, NM 87545 USA. RP Li, DQ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div CST 4, Mail Stop G755,POB 1663, Los Alamos, NM 87545 USA. NR 30 TC 25 Z9 28 U1 1 U2 7 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD SEP 10 PY 2000 VL 69 IS 1-2 BP 75 EP 84 DI 10.1016/S0925-4005(00)00393-2 PG 10 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 355XX UT WOS:000089414800012 ER PT J AU Grant, SA Satcher, JH Bettencourt, K AF Grant, SA Satcher, JH Bettencourt, K TI Development of sol-gel-based fiber optic nitrogen dioxide gas sensors SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE gas sensor; fiber optics; nitrogen dioxide; sol-gel ID POROUS SILICON; NITRIC-OXIDE; THIN-FILM; SURFACE; CO; NO AB We report herein the development of sol-gel-based fiber optic sensors to monitor gaseous nitrogen dioxide based on two different indicating chemistry encapsulations. The first consists of the immobilization of a ruthenium complex, [Ru(bpy)(3)]Cl-2 within a silica sol-gel matrix, while the second design is based on the co-immobilization of the dye Acridine orange and the Saltzman reagent encapsulated within a silica sol-gel matrix. The sensors are placed in a manifold test chamber and nitrogen dioxide gas at various concentrations is flowed into the chamber. A miniature optoelectronics package was developed to acquire data from the sensors. The nitrogen dioxide sensor encapsulating the [Ru(bpy)(3)]Cl-2 demonstrates sensitivity in the hundreds parts per million range with reversibility while the nitrogen dioxide sensor utilizing the Acridine orange dye demonstrates sensitivity in the parts per million range; however, it is not reversible. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Michigan Technol Univ, Ctr Biomed Engn, Houghton, MI 49931 USA. Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. RP Grant, SA (reprint author), Michigan Technol Univ, Ctr Biomed Engn, 1400 Townsend Dr, Houghton, MI 49931 USA. NR 18 TC 25 Z9 26 U1 1 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD SEP 10 PY 2000 VL 69 IS 1-2 BP 132 EP 137 DI 10.1016/S0925-4005(00)00533-5 PG 6 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 355XX UT WOS:000089414800019 ER PT J AU Brosha, EL Mukundan, R Brown, DR Garzon, FH Visser, JH Zanini, M Zhou, Z Logothetis, EM AF Brosha, EL Mukundan, R Brown, DR Garzon, FH Visser, JH Zanini, M Zhou, Z Logothetis, EM TI CO/HC sensors based on thin films of LaCoO3 and La0.8Sr0.2CoO3-delta metal oxides SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE mixed potential; carbon monoxide; hydrocarbon sensors ID ZIRCONIA OXYGEN SENSOR; CARBON-MONOXIDE; CO; ELECTRODES; NONSTOICHIOMETRY; OXIDATION; BEHAVIOR; CR AB We have demonstrated a new type of mixed potential, zirconia-based sensor that utilizes dense, thin films of either La-Sr-Co-O or La-Co-O perovskite transition metal oxide vs. a Au counter electrode to generate an EMF that is proportional to the oxidizable gas species (carbon monoxide (CO), C3H6, and C3H8) concentration in a gas stream containing oxygen. The devices reported in this work were tested at 600 degrees C and 700 degrees C and in gas mixtures containing 0.1% to 20% O-2 concentrations. The metal-oxide-based sensors exhibited an improvement in operating temperature and level stability at elevated temperatures compared to Au-zirconia-Pt mixed potential devices already reported in the literature. However, as with Au-zirconia-Pt devices previously reported, the response behavior reproducibility from device to device was dependent on the Au morphology, which could vary significantly between samples under identical thermal histories. The changing Au morphology on both the Au counter electrode and the Au current collector on the metal oxide electrode were responsible for sensor aging and changes in device response over time. No change in the crystal structure of the perovskite thin film could be seen from XRD. A significant hysteresis in sensor response was found as the background oxygen concentration was cycled through stoichiometry, and this may be attributed to a change in the oxidation state of the cobaltate-based metal oxide electrode. In an effort to mitigate device aging, we replaced the Au counter electrode with a second metal oxide thin film, doped LaMnO3, and demonstrated the operation of a mixed potential sensor based on dual metal oxide electrodes. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Los Alamos Natl Lab, Los Alamos, NM 87454 USA. Ford Motor Co, Res Lab, Dearborn, MI 48121 USA. RP Los Alamos Natl Lab, POB 1663,Mail Stop D429, Los Alamos, NM 87454 USA. EM brosha@lanl.gov NR 30 TC 109 Z9 110 U1 8 U2 37 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD SEP 10 PY 2000 VL 69 IS 1-2 BP 171 EP 182 DI 10.1016/S0925-4005(00)00543-8 PG 12 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 355XX UT WOS:000089414800024 ER PT J AU Feibelman, PJ AF Feibelman, PJ TI Step- versus kink-formation energies on Pt(111) SO SURFACE SCIENCE LA English DT Letter DE density functional calculations; platinum; surface structure, morphology, roughness, and topography ID ABINITIO MOLECULAR-DYNAMICS; WAVE BASIS-SET; ULTRASOFT PSEUDOPOTENTIALS; SURFACES; METALS; FLUCTUATIONS; MORPHOLOGY; TRANSITION; SHAPE AB Ab initio kink-formation energies are about 0.25 and 0.18 eV on the (100)- and (111)-microfacet steps of Pt(111), while the sum of the step-formation energies is similar to 0.75 eV/atom. These results imply a specific ratio of formation energies for the two step types, namely 1.14, in excellent agreement with experiment. If kink-formation costs the same energy on the two step types, an inference recently drawn from scanning probe observations of step wandering, this ratio ought to be unity. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Feibelman, PJ (reprint author), Sandia Natl Labs, Albuquerque, NM 87185 USA. EM pjfeibe@sandia.gov NR 25 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 EI 1879-2758 J9 SURF SCI JI Surf. Sci. PD SEP 10 PY 2000 VL 463 IS 3 BP L661 EP L665 DI 10.1016/S0039-6028(00)00633-6 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 358ZD UT WOS:000089586300003 ER PT J AU Wang, JH Liu, KP Min, ZY Su, HM Bersohn, R Preses, J Larese, JZ AF Wang, JH Liu, KP Min, ZY Su, HM Bersohn, R Preses, J Larese, JZ TI Vacuum ultraviolet photochemistry of CH4 and isotopomers. II. Product channel fields and absorption spectra SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DISSOCIATION; ATMOSPHERES; DYNAMICS; METHANE AB In part I of this work the relative velocities and anisotropies of the atomic H and D fragments from methane photolysis at 10.2 eV were measured. In this paper the relative abundance of the methyl and methylene fragments are reported. A complete set of quantum yields for the different photodissociation channels of each isotopomer is obtained by combining the two sets of data. Previously it was found that H atoms are almost four times more likely than D atoms to be ejected; now it is found that hydrogen molecule photofragments are much richer in H atoms than in D. Overall, the heavier D atoms are more likely than the H atoms to remain attached to the carbon atom. An implication for astrophysics is discussed. The VUV absorption spectra of CH4 and CH3D are almost identical both at room temperature and 75 K. There is, as expected, no variation in the absorption spectrum with temperature. Evidence is given that all or almost all of the methylene is produced in the a (1)A(1) and not in the ground B-3(1) state. (C) 2000 American Institute of Physics. [S0021-9606(00)00934-X]. C1 Acad Sinica, Inst Atom & Mol Sci, Taipei 10764, Taiwan. Columbia Univ, Dept Chem, New York, NY 10027 USA. Brookhaven Natl Lab, Dept Chem 555A, Upton, NY 11973 USA. RP Wang, JH (reprint author), Acad Sinica, Inst Atom & Mol Sci, POB 23-166, Taipei 10764, Taiwan. RI Liu, Kopin/F-7929-2012; Su, Hongmei/S-6093-2016 OI Su, Hongmei/0000-0001-7384-6523 NR 19 TC 58 Z9 58 U1 1 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 SEP 8 PY 2000 VL 113 IS 10 BP 4146 EP 4152 DI 10.1063/1.1288145 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 349GC UT WOS:000089034900027 ER PT J AU Bise, RT Hoops, AA Choi, H Neumark, DM AF Bise, RT Hoops, AA Choi, H Neumark, DM TI Photodissociation dynamics of the CNN free radical SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LASER-INDUCED-FLUORESCENCE; FLIGHT MASS-SPECTROMETER; MOLECULES CCO; SPECTROSCOPY; TRIPLET; STATES; DIAZOMETHANE; MATRIX; TIME; DISSOCIATION AB The spectroscopy and photodissociation dynamics of the (A) over tilde (3)Pi and (B) over tilde (3)Sigma(-) states of the CNN radical have been investigated by fast beam photofragment translational spectroscopy. Vibronic transitions located more than 1000 cm(-1) above the (A) over tilde (3)Pi<--(X) over tilde (3)Sigma(-) origin were found to predissociate. Photofragment yield spectra for the (B) over tilde (3)Sigma(-)<--(X) over tilde (3)Sigma(-) band between 40 800 and 45 460 cm(-1) display resolved vibrational progressions with peak spacing of approximate to 1000 cm(-1) corresponding to symmetric stretch 1(0)(n) and combination band 1(0)(n)3(0)(1) progressions. Ground state products C(P-3)+N-2 were found to be the major photodissociation channel for both the (A) over tilde (3)Pi and (B) over tilde (3)Sigma(-) states. The translational energy distributions for the (A) over tilde (3)Pi state are bimodal with high and low translational energy components. The distributions for the (B) over tilde (3)Sigma(-) state reveal partially resolved vibrational structure for the N-2 photofragment and indicate extensive vibrational and rotational excitation of this fragment. These results suggest that bent geometries are involved in the dissociation mechanism and provide more accurate values: Delta(f)H(0)(CNN)=6.16 +/- 0.05 eV and Delta(f)H(298)(CNN)=6.15 +/- 0.05 eV. These values, coupled with recent D-0(RH) and D-298(RH) values from Clifford [J. Phys. Chem. 102, 7100 (1998)], yield Delta(f)H(0)(HCNN)=5.02 +/- 0.18 eV, Delta(f)H(298)(HCNN)=4.98 +/- 0.18 eV, Delta(f)H(0)(H2CNN)=3.09 +/- 0.21 eV, and Delta(f)H(0)(H2CNN)=3.09 +/- 0.21 eV. (C) 2000 American Institute of Physics. [S0021-9606(00)01334-9]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM dan@radon.cchem.berkeley.edu RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 51 TC 13 Z9 13 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 8 PY 2000 VL 113 IS 10 BP 4179 EP 4189 AR PII [S0021-9606(00)01334-9] DI 10.1063/1.1288267 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 349GC UT WOS:000089034900031 ER PT J AU Raptis, CA Pratt, ST AF Raptis, CA Pratt, ST TI Mode-dependent vibrational autoionization in aniline SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID JET-COOLED ANILINE; ROTATIONAL STATE DISTRIBUTIONS; SUPERSONIC FREE JET; RYDBERG STATES; PHOTOIONIZATION SPECTROSCOPY; THRESHOLD PHOTOIONIZATION; RESONANCE SPECTROSCOPY; PHOTOELECTRON-SPECTRA; 2-COLOR; H-2 AB High-resolution photoelectron spectroscopy is used to study the branching ratios for vibrational autoionization of Rydberg states of aniline (C6H5NH2) converging to the ground electronic state of the ion. By using two-color double-resonance excitation, it is possible to prepare autoionizing resonances in which two different vibrational modes are excited. Determination of the vibrational state distribution in the product ion provides information on the relative rates of autoionization for the two modes. It is found that some normal modes appear to be especially effective at promoting vibrational autoionization, while others appear to be completely ineffective. (C) 2000 American Institute of Physics. [S0021-9606(00)00834-5]. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Raptis, CA (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 35 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 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 8 PY 2000 VL 113 IS 10 BP 4190 EP 4202 AR PII [S0021-9606(00)00834-5] DI 10.1063/1.1288144 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 349GC UT WOS:000089034900032 ER PT J AU Miyabe, K Guiochon, G AF Miyabe, K Guiochon, G TI Influence of the column radial heterogeneity on the determination of single-component isotherms by the elution by characteristic point method SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE column radial heterogeneity; elution by characteristic point; mass transfer resistance ID LIQUID-CHROMATOGRAPHY; LINEAR CHROMATOGRAPHY; FLOW VELOCITY; DISPERSION; BEDS; EFFICIENCY; BANDS AB The influence of the column radial heterogeneity on the determination of equilibrium isotherm data by the elution by characteristic point (ECP) method is studied using nondimensional numerical calculations and taking into account typical radial distributions of the mobile phase flow velocity and the column efficiency across a column. Overloaded elution peaks were calculated with the equilibrium-dispersive model as a function of four dimensionless parameters, the number of theoretical plates at the center of the column, the Langmuir equilibrium constant, the retention and the loading factors. The influence of the mass transfer resistances and the radial heterogeneity of the column on the ECP data was analyzed by comparing the true isotherm and the one estimated from the diffuse profile of overloaded peaks. The results provide information on the accuracy of the ECP method. The error made increases with increasing degree of radial heterogeneity. This error can be corrected by using the results of the nondimensional numerical calculations, allowing a further extension of the applicability of the ECP method. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Analyt Sci Div, Oak Ridge, TN 37831 USA. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 24 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD SEP 8 PY 2000 VL 891 IS 2 BP 217 EP 233 DI 10.1016/S0021-9673(00)00656-7 PG 17 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 353QB UT WOS:000089286000002 PM 11043782 ER PT J AU Gavaghan, DJ Feldberg, SW AF Gavaghan, DJ Feldberg, SW TI Extended electron transfer and the Frumkin correction SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE Butler-Volmer theory; capacitance; diffuse layer potential; extended electron transfer; frumkin correction; Marcus theory ID DISTANCE DEPENDENCE; TRAPPED ELECTRONS; TRANSFER KINETICS; MONOLAYERS; FERROCENE; RATES; GOLD AB It is now well established that the rate constant for electron transfer between a metal electrode and a given redox moiety (at distance x from the electrode) decays according to exp[ - betax]; values of beta are of the order of 10(8) cm(-1) and depend primarily upon the nature of the intervening medium. The present work demonstrates how this 'extended' electron transfer can modify the Frumkin correction for diffuse layer effects in the measurement of heterogeneous rate constants. We quantify the effect of this 'extended' electron transfer by comparing the electron transfer rate constants deduced with (k'(eff)) and without (k(eff)) extended electron transfer. Butler-Volmer kinetics and a single electron transfer are assumed. The ratio k'(eff)/k(eff) is deduced as a function of beta/kappa, where kappa is the reciprocal Debye length; (F/RT)phi (PCA) where phi (PCA) is the diffuse layer potential at the plane of closest approach; and z(ox) - alpha, where z(ox) is the charge of the oxidized redox species and alpha is the Butler-Volmer transfer coefficient. The deviation of k'(eff)/k(eff) from unity is greatest when the diffuse layer potential, phi (x), decays over distances of a few angstroms from the plane of closest approach, as is the case with higher concentrations of supporting electrolyte and/or large values of the diffuse layer potential. When /Z(ox)/ less than or equal to /z(se)/ and /Z(red)/ less than or equal to /Z(se)/ the classical Frumkin expression is applicable as long as -ln[1 + beta/kappa] less than or equal to F/RT phi (PCA)(z(ox) - alpha) less than or equal to ln[1 + beta/kappa] When /Z(ox)/ > /Z(se)/ or /Z(red)/ > /Z(se)/ and (F/RT)phi (PCA)(Z(ox) - alpha)< 0 redox ions can become a significant component of the diffuse layer and the classical Gouy-Chapman theory is no longer applicable. To avoid this complication and apply the classical Frumkin correction the condition to be met is 0 (F/RT)phi (PCA)(z(ox) - alpha) less than or equal to ln[1 + beta/kappa] thus ensuring that the redox species is not disproportionately accumulated in the diffuse layer. We also show that when beta/kappa less than or equal to 0.5, phi (PCA)Z(ox) greater than or equal to 0 and phi (PCA)z(red) greater than or equal to 0 then virtually all ET occurs outside the diffuse layer and there is no Frumkin effect. However, this condition is not easily achieved experimentally. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Monash Univ, Dept Chem, Clayton, Vic 3168, Australia. RP Feldberg, SW (reprint author), Brookhaven Natl Lab, Energy Sci & Technol Dept, Upton, NY 11973 USA. OI gavaghan, david/0000-0001-8311-3200 NR 36 TC 29 Z9 29 U1 3 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD SEP 8 PY 2000 VL 491 IS 1-2 BP 103 EP 110 DI 10.1016/S0022-0728(00)00210-2 PG 8 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 381QB UT WOS:000165773500012 ER PT J AU Dinh, HN Ren, XM Garzon, FH Zelenay, P Gottesfeld, S AF Dinh, HN Ren, XM Garzon, FH Zelenay, P Gottesfeld, S TI Electrocatalysis in direct methanol fuel cells: in-situ probing of PtRu anode catalyst surfaces SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE direct methanol fuel cell; PtRu; electrocatalyst; CO stripping; catalyst surface composition; XRD ID ELECTROOXIDATION; RUTHENIUM; CO; PERFORMANCE; OXIDATION AB Stripping voltammetry of CO adsorbed at unsupported, highly dispersed PtRu anode catalysts, is demonstrated here as an in-situ probe of surface composition for this type of direct methanol fuel cell (DMFC) catalyst. Reported data [1] for stripping voltammetry of CO adsorbed at bulk PtRu alloy electrode surfaces served as the basis for this in-situ surface diagnostic. CO stripping data collected in this work for three dispersed, unsupported PtRu catalyst samples - all of significant oxygen content as received - strongly suggest that surface metal alloy domains of atomic ratio Ru:Pt near 1:1 are key for higher DMFC anode activity. The PtRu catalyst sample of highest DMFC anode activity displays highest CO stripping peak currents and charges per unit (BET) surface area under a given scan rate and temperature. This indicates higher population of metal alloy sites, free of blocking by oxide components of the sample. Combined data from CO stripping and XRD measurements indicate that a higher degree of overall alloying, as brought about by more extensive sample reduction, results also in a more reduced catalyst surface. We conclude that the activity of unsupported, dispersed PtRu catalysts in anodic oxidation of methanol depends on two major factors: maximized catalyst surface area and a catalyst surface with maximum number of metal ahoy sites of atomic ratio close to I:1. The best DMFC anode catalyst sample examined by us has a BET surface area (as received) of 70 m(2) g(-1) and the CO stripping data suggest that, in the fuel cell at the relevant anode potential, 50% of that BET surface area is metal PtRu alloy of composition near 1:1. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, Los Alamos, NM 87545 USA. RP Gottesfeld, S (reprint author), Univ Calif Los Alamos Natl Lab, Mat Sci & Technol Div, POB 1663,Mailstop D429, Los Alamos, NM 87545 USA. RI ren, xiaoming/F-3953-2011 NR 18 TC 227 Z9 232 U1 8 U2 68 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD SEP 8 PY 2000 VL 491 IS 1-2 BP 222 EP 233 DI 10.1016/S0022-0728(00)00271-0 PG 12 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 381QB UT WOS:000165773500027 ER PT J AU Cort, JR Yee, A Edwards, AM Arrowsmith, CH Kennedy, MA AF Cort, JR Yee, A Edwards, AM Arrowsmith, CH Kennedy, MA TI Structure-based functional classification of hypothetical protein MTH538 from Methanobacterium thermoautotrophicum SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE structural genomics; NMR; CheY; AmiR; flavodoxin ID SUBTILIS RESPONSE REGULATOR; ANGSTROM CRYSTAL-STRUCTURE; HIGH-RESOLUTION NMR; ESCHERICHIA-COLI; BACTERIAL CHEMOTAXIS; THERMOTOGA-MARITIMA; COUPLING-CONSTANTS; MAGNESIUM-BINDING; CHEMICAL-SHIFTS; GENE-PRODUCT AB The structure of MTH538, a previously uncharacterized hypothetical protein from Methanobacterium thermoautotrophicum, has been determined by NMR spectroscopy. MTH538 is one of numerous structural genomics targets selected in a genome-wide survey of uncharacterized sequences from this organism. MTH538 is a so-called singleton, a sequence not closely related to any other (known) sequences. The structure of MTH538 closely resembles the known structures of receiver domains from two component response regulator systems, such as CheY, and is similar to the structures of flavodoxins and GTP-binding proteins. Tests on MTH538 for characteristic activities of CheY and flavodoxin were negative. MTH538 did not become phosphorylated in the presence of acetyl phosphate and Mg2+, although it appeared to bind Mg2+. MTH538 also did not bind flavin mononucleotide (FMN) or coenzyme F-420. Nevertheless, sequence and structure parallels between MTH538/CheY and two families of ATPase/phosphatase proteins suggest that MTH538 may have a role in a phosphorylation-independent two-component response regulator system. (C) 2000 Academic Press. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Toronto, Dept Med Biophys, Toronto, ON M5G 2M9, Canada. Univ Toronto, Ontario Canc Inst, Toronto, ON M5G 2M9, Canada. Univ Toronto, Charles H Best Inst, Banting & Best Dept Med Res, Toronto, ON M5G 1L6, Canada. RP Kennedy, MA (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, EMSL 2569 K8-98, Richland, WA 99352 USA. NR 63 TC 17 Z9 18 U1 0 U2 4 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 SEP 8 PY 2000 VL 302 IS 1 BP 189 EP 203 DI 10.1006/jmbi.2000.4052 PG 15 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 354WE UT WOS:000089352000014 PM 10964569 ER PT J AU Ritchie, B Weatherford, CA AF Ritchie, B Weatherford, CA TI Nonperturbative theory of Coulombic retardation in relativistic quantum mechanics SO JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM LA English DT Article; Proceedings Paper CT 8th Annual Conference on Current Trends in Computational Chemistry (CCTCC) CY NOV 05-06, 1999 CL VICKSBURG, MISSISSIPPI DE nonperturbative theory; Coulombic retardation; relativistic quantum mechanics ID ABSORPTION AB Retardation causes the Coulomb field of a moving point particle to be pinched in a direction transverse to the direction of the particle's velocity. The pinch is expected to be strong as the velocity approaches the speed of light, a situation which arises at small interparticle distances between particles of opposite charge and equal mass, where the motion would be expected to be strongly one-dimensional and hence strongly binding in the direction of the pinch. The Klein-Gordon and Dirac equations are solved for this situation; the results suggest that an alternative interpretation for positron-electron annihilation might be two-photon decay to a quantum state describing strong two-body binding in the direction of the pinch of the retarded potential. The alternative interpretation is supported by the fundamental relativistic energy-momentum relation, (E - V)(2) = m(2)c(4) + c(2)p(2), which guarantees, for a removable V-2 singularity at the origin, that the energy goes to zero as the quantum-mechanical mean of V goes to -infinity. In the present strong-binding theory any residual mass between zero mass (Dirac interpretation) and the mass implied by the imprecision of energy-release measurements is consistent with existing experimental knowledge of annihilation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Florida A&M Univ, Dept Phys, Tallahassee, FL 32307 USA. RP Ritchie, B (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-1280 J9 J MOL STRUC-THEOCHEM JI Theochem-J. Mol. Struct. PD SEP 8 PY 2000 VL 529 SI SI BP 113 EP 122 DI 10.1016/S0166-1280(00)00537-6 PG 10 WC Chemistry, Physical SC Chemistry GA 358EE UT WOS:000089543600015 ER PT J AU Stankovic, S Espenson, JH AF Stankovic, S Espenson, JH TI Oxidation of methyl trimethylsilyl ketene acetals to alpha-hydroxyesters with urea hydrogen peroxide catalyzed by methyltrioxorhenium SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID MAIN-GROUP ELEMENTS; SILYL ENOL ETHERS; METHYLRHENIUM TRIOXIDE; TRANSITION-METALS; MOLECULAR-OXYGEN; MULTIPLE BONDS; EPOXIDATION; MECHANISM; HYDROLYSIS; KINETICS AB In the presence of catalytic amounts of MTO, methyltrioxorhenium, methyl trimethylsilyl ketene acetals are oxidized with urea hydrogen peroxide to afford alpha-hydroxy and alpha-siloxy esters. On treatment with potassium fluoride, the alpha-hydroxy esters are obtained in high yields. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 29 TC 13 Z9 13 U1 1 U2 9 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 SEP 8 PY 2000 VL 65 IS 18 BP 5528 EP 5530 DI 10.1021/jo000212e PG 3 WC Chemistry, Organic SC Chemistry GA 354BP UT WOS:000089310200011 ER PT J AU Fang, XG Huhmann-Vincent, J Scott, BL Kubas, GJ AF Fang, XG Huhmann-Vincent, J Scott, BL Kubas, GJ TI H-2 binding to and silane alcoholysis on an electrophilic Mn(I) fragment with tied-back phosphite ligands. X-ray structure of a Mn-CH2Cl2 complex SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE manganese; dichloromethane; dihydrogen; silane; phosphite; cyclooctene ID COORDINATING SOLVENT; HYDROGEN COMPLEXES; RHENIUM COMPLEXES; NMR-SPECTROSCOPY; METAL FRAGMENTS; H BOND; REACTIVITY; ACTIVATION; DIHYDROGEN; N-2 AB The solvent-coordinated cationic complex [mer-Mn(CO)(3){P(OCH2)(3)CMe}(2)(ClCH2Cl)][BArF] (4), has been prepared by the reaction of the methyl precursor mer-Mn(Me)(CO)(3)(P(OCH2)(3)CMe}(2) with [Ph3C][BArF]. The coordinated solvent, CH2Cl2, binds to Mn through one chloride atom in the X-ray crystal structure, which also exhibits novel interligand hydrogen bonding between an acidic hydrogen on CH2Cl2 and an oxygen of the phosphite. 4 binds H-2 in equilibrium fashion, and the eta(2)-H-2 complex has a very high J(HD) of 34.5 Hz indicative of the high electrophilicity of the metal center. Silanes also displace the bound CH2Cl2 at low temperature, although the eta(2)-Si-H bond undergoes heterolytic cleavage on warming. 4 catalyzes reaction of SiHEt3 with phenol to give Et3SiOPh and H-2. The bound CH2Cl2 in 4 is displaced irreversibly by olefins, ethers, and amines, to form stable adducts. The cationic [Mn(CO)(3)(P(OCH2)(3)CMe)(2)](+) fragment is more electrophilic than phosphine analogues, and the tied-back phosphites give less steric congestion and, importantly, cannot engage in agostic interactions that would compete with external ligand binding. The results in these and other related systems bring to the forefront the subtle balance between electronic and steric forces that occur on addition of sixth ligands to 16 e(-) metal fragments. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Kubas, GJ (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 43 TC 50 Z9 50 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD SEP 8 PY 2000 VL 609 IS 1-2 BP 95 EP 103 DI 10.1016/S0022-328X(00)00230-8 PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 363HP UT WOS:000089829900014 ER PT J AU Kaiser, EW Wailington, TJ Hurley, MD Platz, J Curran, HJ Pitz, WJ Westbrook, CK AF Kaiser, EW Wailington, TJ Hurley, MD Platz, J Curran, HJ Pitz, WJ Westbrook, CK TI Experimental and modeling study of premixed atmospheric-pressure dimethyl ether-air flames SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID OXIDATION; MECHANISM; PROFILES; KINETICS AB Chemical species profiles have been measured at atmospheric pressure for two dimethyl ether (DME)-air flat flames having fuel/air equivalence ratios of 0.67 and 1.49. The samples, obtained with an uncooled quartz probe, were analyzed by either gas chromatography or Fourier transform infrared (FTIR) spectroscopy for CH4, C2H2, C2H4, C2H6, C3H8, DME, CO, CO2, O-2, CH2O, and formic acid. a pneumatic probe calibrated at a reference position in the burned gas by a radiation-corrected thermocouple provided temperature profiles for each flame. Species profiles for two methane-air flames with equivalence ratios and cold-gas flow velocities similar to those of the DME flames were also obtained for comparison to the DME results, Mole fractions of C-2 product species were similar in DME and methane flames of similar equivalence ratios. However, the CH2O mole fractions were 5-10 times larger in the DME flames. These experimental profiles are compared to profiles generated in a computer modeling study using the best available DME-air chemical kinetic mechanism. The Appendix presents photographs of DME, methane, and ethane diffusion flames. These results show that, while DME produces soot, its yellow flame luminosity is much smaller than that of an ethane flame at the same fuel volume flow rate, consistent with the low soot emission rate observed when DME is used as a diesel fuel. C1 Ford Motor Co, Dept Chem, Dearborn, MI 48121 USA. Natl Environm Inst, DK-4000 Roskilde, Denmark. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kaiser, EW (reprint author), Ford Motor Co, Dept Chem, POB 2053,Mail Drop 3083-SRL, Dearborn, MI 48121 USA. OI Curran, Henry/0000-0002-5124-8562 NR 27 TC 117 Z9 124 U1 2 U2 25 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 SEP 7 PY 2000 VL 104 IS 35 BP 8194 EP 8206 DI 10.1021/jp994074c PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 359HC UT WOS:000089604600006 ER PT J AU Schreckenbach, G Wolff, SK Ziegler, T AF Schreckenbach, G Wolff, SK Ziegler, T TI NMR shielding calculations across the periodic table: Diamagnetic uranium compounds. 1. Methods and issues SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DENSITY-FUNCTIONAL THEORY; NUCLEAR-MAGNETIC-RESONANCE; INCLUDING ATOMIC ORBITALS; ORDER REGULAR APPROXIMATION; TRANSITION-METAL COMPLEXES; INHOMOGENEOUS ELECTRON-GAS; EFFECTIVE-CORE POTENTIALS; CHEMICAL-SHIFTS; HARTREE-FOCK; CORRELATION-ENERGY AB In this and a subsequent article, the range of application for relativistic density functional theory (DFT) is extended to the calculation of nuclear magnetic resonance (NMR) shieldings and chemical shifts in diamagnetic actinide compounds. In the given first paper, various issues are explored that are related to this goal. dt is shown that both the relativistic DFT-ZORA (zeroth-order regular approximation, as developed for NMR properties by Wolff, S. K.; Ziegler, T.; van Lenthe, E.; Baerends, E. J. J. Chem. Phys. 1999, 110, 7689) and the older quasi-relativistic (QR) DFT methods are applicable to these compounds. Another popular relativistic method, the use of relativistic effective core potentials (ECP) for the calculation of ligand NMR parameters, is tested as well. It is demonstrated that the ECP approach is beyond its limits for the very heavy actinide compounds. Comparing the ZORA and Pauli approaches, it is found that Pauli is mon accurate for the H-1 NMR in UF6-n(OCH3)(n) compounds whereas ZORA is more accurate in other cases. This is in contrast to earlier studies that always showed ZORA to be superior. The neglect of spin-orbit effects, leading to scalar relativistic approximations, is possible in some cases. In other cases, however, spin-orbit cannot be neglected. For instance in UF5(OCH3), a large spin-orbit chemical shift of about 7 ppm has been found for the H-1 nuclei but only small effects for the other Ligand nuclei. The large influences of the reference geometry, the reference compound, and the exchange correlation (XC) functional are demonstrated and discussed. The F-19 chemical shift tensor in UF6 is well reproduced by the ZORA and QR methods. However, for the F-19 chemical shifts in UF6-nClpi compounds, only some experimental trends could be reproduced by the calculations. Possible explanations are discussed, for these shortcomings, including the choice of model XC functional. C1 Los Alamos Natl Lab, Div Theoret MS B268, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Seaborg Inst Transactinium Sci, Los Alamos, NM 87545 USA. Vrije Univ Theoret Chem, NL-1081 HV Amsterdam, Netherlands. Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada. RP CLRC, Daresbury Lab, Dept Computat Sci & Engn, Warrington WA4 4AD, Cheshire, England. RI Ziegler, Tom/D-7863-2012 NR 94 TC 51 Z9 51 U1 1 U2 6 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 SEP 7 PY 2000 VL 104 IS 35 BP 8244 EP 8255 DI 10.1021/jp001143a PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 359HC UT WOS:000089604600012 ER PT J AU Park, H Park, J Lim, AKL Anderson, EH Alivisatos, AP McEuen, PL AF Park, H Park, J Lim, AKL Anderson, EH Alivisatos, AP McEuen, PL TI Nanomechanical oscillations in a single-C-60 transistor SO NATURE LA English DT Article ID CARBON NANOTUBES; C-60; NANOCRYSTALS; SPECTROSCOPY; MICROSCOPY; MOLECULE; WIRES AB The motion of electrons through quantum dots is strongly modified by single-electron charging and the quantization of energy levels(1,2). Much effort has been directed towards extending studies of electron transport to chemical nanostructures, including molecules(3-8), nanocrystals(9-13) and nanotubes(14-17). Here we report the fabrication of single-molecule transistors based on individual C-60 molecules connected to gold electrodes. We perform transport measurements that provide evidence for a coupling between the centre-of-mass motion of the C-60 molecules and single-electron hopping(18)-a conduction mechanism that has not been observed previously in quantum dot studies. The coupling is manifest as quantized nano-mechanical oscillations of the C-60 molecule against the gold surface, with a frequency of about 1.2 THz. This value is in good agreement with a simple theoretical estimate based on van der Waals and electrostatic interactions between C-60 molecules and gold electrodes. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP McEuen, PL (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Park, Jiwoong/C-2327-2013; Alivisatos , Paul /N-8863-2015 OI Alivisatos , Paul /0000-0001-6895-9048 NR 26 TC 1347 Z9 1360 U1 19 U2 151 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD SEP 7 PY 2000 VL 407 IS 6800 BP 57 EP 60 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 350WE UT WOS:000089124000038 ER PT J AU Eichler, R Bruchle, W Dressler, R Dullmann, CE Eichler, B Gaggeler, HW Gregorich, KE Hoffman, DC Hubener, S Jost, DT Kirbach, UW Laue, CA Lavanchy, VM Nitsche, H Patin, JB Piguet, D Schadel, M Shaughnessy, DA Strellis, DA Taut, S Tobler, L Tsyganov, YS Turler, A Vahle, A Wilk, PA Yakushev, AB AF Eichler, R Bruchle, W Dressler, R Dullmann, CE Eichler, B Gaggeler, HW Gregorich, KE Hoffman, DC Hubener, S Jost, DT Kirbach, UW Laue, CA Lavanchy, VM Nitsche, H Patin, JB Piguet, D Schadel, M Shaughnessy, DA Strellis, DA Taut, S Tobler, L Tsyganov, YS Turler, A Vahle, A Wilk, PA Yakushev, AB TI Chemical characterization of bohrium (element 107) SO NATURE LA English DT Article ID SUPERHEAVY NUCLEI; SEABORGIUM; IDENTIFICATION; CHEMISTRY; ISOTOPES; RHENIUM; SEARCH AB The arrangement of the chemical elements in the periodic table highlights resemblances in chemical properties, which reflect the elements' electronic structure. For the heaviest elements, however, deviations in the periodicity of chemical properties are expected(1-3): electrons in orbitals with a high probability density near the nucleus are accelerated by the large nuclear charges to relativistic velocities, which increase their binding energies and cause orbital contraction. This leads to more efficient screening of the nuclear charge and corresponding destabilization of the outer d and f orbitals: it is these changes that can give rise to unexpected chemical properties. The synthesis of increasingly heavy elements(4-6), now including that of elements 114, 116 and 118, allows the investigation of this effect, provided sufficiently long-lived isotopes for chemical characterization are available(7). In the case of elements 104 and 105, for example, relativistic effects interrupt characteristic trends in the chemical properties of the elements constituting the corresponding columns of the periodic table(8), whereas element 106 behaves in accordance with the expected periodicity(9-12). Here we report the chemical separation and characterization of six atoms of element 107 (bohrium, Bh), in the form of its oxychloride. We find that this compound is less volatile than the oxychlorides of the lighter elements of group VII, thus confirming relativistic calculations(13) that predict the behaviour of bohrium, like that of element 106, to coincide with that expected on the basis of its position in the periodic table. C1 Univ Bern, Dept Chem & Biochem, CH-3012 Bern, Switzerland. Paul Scherrer Inst, Lab Radio & Umweltchem, CH-5232 Villigen, Switzerland. Gesell Schwerionenforsch GmbH, D-64291 Darmstadt, Germany. Tech Univ Dresden, Inst Analyt Chem, D-01062 Dresden, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Rossendorf Inc, Forschungszentrum Rossendorf EV, Inst Radiochem, D-01314 Dresden, Germany. Joint Inst Nucl Res, Flerov Lab Nucl React, Dubna 141980, Russia. RP Gaggeler, HW (reprint author), Univ Bern, Dept Chem & Biochem, CH-3012 Bern, Switzerland. RI Wilk, Philip/B-5954-2008; Eichler, Robert/G-5130-2011; Turler, Andreas/D-3913-2014 OI Turler, Andreas/0000-0002-4274-1056 NR 30 TC 77 Z9 81 U1 2 U2 13 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD SEP 7 PY 2000 VL 407 IS 6800 BP 63 EP 65 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 350WE UT WOS:000089124000040 ER PT J AU Link, JM Paolone, VS Reyes, M Yager, PM Anjos, JC Bediaga, I Gobel, C Magnin, J de Miranda, JM Pepe, IM dos Reis, AC Simao, FRA Carrillo, S Casimiro, E Mendez, H Sanchez-Hernandez, A Uribe, C Vazquez, F Cinquini, L Cumalat, JP Ramirez, JE O'Reilly, B Vaandering, EW Butler, JN Cheung, HWK Gaines, I Garbincius, PH Garren, LA Gottschalk, E Gourlay, SA Kasper, PH Kreymer, AE Bianco, S Fabbri, FL Sarwar, S Zallo, A Cawlfield, C Kutschke, R Kim, DY Park, KS Rahimi, A Wiss, J Gardner, R Chung, YS Kang, JS Ko, BR Kwak, JW Lee, KB Myung, SS Park, H Alimonti, G Boschini, M Brambilla, D Caccianiga, B Calandrino, A D'Angelo, P DiCorato, M Dini, P Giammarchi, M Inzani, P Leveraro, F Malvezzi, S Menasce, D Mezzadri, M Milazzo, L Moroni, L Pedrini, D Prelz, F Rovere, M Sala, A Sala, S Davenport, TF Arena, V Boca, G Bonomi, G Gianini, G Liguori, G Merlo, M Pantea, D Ratti, SP Riccardi, C Torre, P Viola, L Vitulo, P Hernandez, H Lopez, AM Mendez, L Mirles, A Montiel, E Olaya, D Quinones, J Rivera, C Zhang, Y Copty, N Purohit, M Wilson, JR Cho, K Handler, T Engh, D Johns, WE Hosack, M Nehring, MS Sales, M Sheldon, PD Stenson, K Webster, MS Sheaff, M Kwon, YJ AF Link, JM Paolone, VS Reyes, M Yager, PM Anjos, JC Bediaga, I Gobel, C Magnin, J de Miranda, JM Pepe, IM dos Reis, AC Simao, FRA Carrillo, S Casimiro, E Mendez, H Sanchez-Hernandez, A Uribe, C Vazquez, F Cinquini, L Cumalat, JP Ramirez, JE O'Reilly, B Vaandering, EW Butler, JN Cheung, HWK Gaines, I Garbincius, PH Garren, LA Gottschalk, E Gourlay, SA Kasper, PH Kreymer, AE Bianco, S Fabbri, FL Sarwar, S Zallo, A Cawlfield, C Kutschke, R Kim, DY Park, KS Rahimi, A Wiss, J Gardner, R Chung, YS Kang, JS Ko, BR Kwak, JW Lee, KB Myung, SS Park, H Alimonti, G Boschini, M Brambilla, D Caccianiga, B Calandrino, A D'Angelo, P DiCorato, M Dini, P Giammarchi, M Inzani, P Leveraro, F Malvezzi, S Menasce, D Mezzadri, M Milazzo, L Moroni, L Pedrini, D Prelz, F Rovere, M Sala, A Sala, S Davenport, TF Arena, V Boca, G Bonomi, G Gianini, G Liguori, G Merlo, M Pantea, D Ratti, SP Riccardi, C Torre, P Viola, L Vitulo, P Hernandez, H Lopez, AM Mendez, L Mirles, A Montiel, E Olaya, D Quinones, J Rivera, C Zhang, Y Copty, N Purohit, M Wilson, JR Cho, K Handler, T Engh, D Johns, WE Hosack, M Nehring, MS Sales, M Sheldon, PD Stenson, K Webster, MS Sheaff, M Kwon, YJ CA FOCUS Collaboration TI Measurements of the Sigma(0)(c) and Sigma(++)(c) mass splittings SO PHYSICS LETTERS B LA English DT Article ID SIGMA-C++; BARYONS AB Using a high statistics sample of photoproduced charmed particles from the FOCUS experiment at Fermilab (FNAL-E831), we measure the mass splittings of the charmed baryons Sigma(c)(0) and Sigma(c)(++). We find M(Sigma(c)(0) - Lambda(c)) = 167.38 +/- 0.21 +/- 0.13 MeV/c(2) and M(Sigma(c)(++) - Lambda(c)(+)) = 167.35 +/- 0.19 +/- 0.12 MeV/c(2) with samples of 362 +/- 36 and 461 +/- 39 events, respectively. We measure the isospin mass splitting M(Sigma(c)(++) - Sigma(c)(0)) to be -0.03 +/- 0.28 +/- 0.11 MeV/c(2). The first errors are statistical and the second are systematic. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Davis, Davis, CA 95616 USA. Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil. CINVESTAV, Mexico City 07000, DF, Mexico. Univ Colorado, Boulder, CO 80309 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Illinois, Urbana, IL 61801 USA. Indiana Univ, Bloomington, IN 47405 USA. Korea Univ, Seoul 136701, South Korea. Ist Nazl Fis Nucl, I-20133 Milan, Italy. Univ Milan, Milan, Italy. Univ N Carolina, Asheville, NC 28804 USA. Dipartimento Fis Nucl & Teor, Pavia, Italy. Ist Nazl Fis Nucl, I-27100 Pavia, Italy. Univ Puerto Rico, Mayaguez, PR 00681 USA. RP Link, JM (reprint author), Univ Calif Davis, Davis, CA 95616 USA. RI Bonomi, Germano/G-4236-2010; Kwak, Jungwon/K-8338-2012; Anjos, Joao/C-8335-2013; Link, Jonathan/L-2560-2013; Gobel Burlamaqui de Mello, Carla /H-4721-2016; OI Bonomi, Germano/0000-0003-1618-9648; Link, Jonathan/0000-0002-1514-0650; Gobel Burlamaqui de Mello, Carla /0000-0003-0523-495X; Kutschke, Robert/0000-0001-9315-2879 NR 18 TC 7 Z9 7 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 SEP 7 PY 2000 VL 488 IS 3-4 BP 218 EP 224 DI 10.1016/S0370-2693(00)00867-4 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 355PT UT WOS:000089394600002 ER PT J AU Xie, SB Iglesia, E Bell, AT AF Xie, SB Iglesia, E Bell, AT TI Effects of hydration and dehydration on the structure of silica-supported vanadia species SO LANGMUIR LA English DT Article ID OXIDE CATALYSTS; OXIDATIVE DEHYDROGENATION; RAMAN-SPECTROSCOPY; METHANOL OXIDATION; ALKANES; VAPOR; XANES; GELS; V2O5; NMR AB The effects of hydration and dehydration of silica-supported vanadia have been investigated with the aim of understanding how these processes alter the structure of the dispersed vanadia. Samples containing either 9 or 12 wt % V2O5/SiO2 were examined by in situ Raman spectroscopy during hydration in 3 kPa water vapor at room temperature and during dehydration at temperatures between 298 and 773 K. The vanadia in freshly dehydrated 9 wt % V2O5/SiO2 is present exclusively in the form of monovanadate species. Monovanadate species are predominant in the 12 wt % V2O5/SiO2, but a small amount of V2O5 is present as well. Room-temperature hydration causes a progressive loss of the Raman band at 1043 cm(-1) characteristic of isolated monovanadate species, and the gradual appearance of bands at 1021, 986, 895, 773, 706, 666, 512, 415, 325, 267, and 158 cm(-1) characteristic of a hydrated vanadia gel. Dehydration at elevated temperatures decomposes the gel and partially restores the presence of isolated monovanadate species. V2O5 particles are also formed during dehydration. Repeated low-temperature hydration and high-temperature dehydration leads to an irreversible conversion of isolated monovanadate species into V2O5 particles. A mechanism by which this process occurs is proposed. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Iglesia, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem, Berkeley, CA 94720 USA. RI Iglesia, Enrique/D-9551-2017; OI Iglesia, Enrique/0000-0003-4109-1001; Bell, Alexis/0000-0002-5738-4645 NR 34 TC 76 Z9 76 U1 0 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD SEP 5 PY 2000 VL 16 IS 18 BP 7162 EP 7167 DI 10.1021/la0003342 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 350UA UT WOS:000089118500011 ER PT J AU Yan, Y Al-Jassim, MM Jones, KM Wei, SH Zhang, SB AF Yan, Y Al-Jassim, MM Jones, KM Wei, SH Zhang, SB TI Observation and first-principles calculation of buried wurtzite phases in zinc-blende CdTe thin films SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; SOLAR-CELL; GROWTH AB We report direct observation of the existence of buried thin wurtzite CdTe layers in nominally pure zinc-blende CdTe thin films using high-resolution transmission electron microscopy. The formation of the buried wurtzite layers is a result of the formation of high density of planar defects in the zinc-blende films-the wurtzite layers are formed by closely spaced lamellar twins. First-principles calculations reveal that the presence of the buried wurtzite layers may be responsible for the poor electrical properties of the polycrystalline zinc-blende CdTe films. (C) 2000 American Institute of Physics. [S0003-6951(00)04836-1]. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Yan, Y (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Krausnick, Jennifer/D-6291-2013; Zhang, Shengbai/D-4885-2013 OI Zhang, Shengbai/0000-0003-0833-5860 NR 18 TC 43 Z9 43 U1 0 U2 8 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 SEP 4 PY 2000 VL 77 IS 10 BP 1461 EP 1463 DI 10.1063/1.1308062 PG 3 WC Physics, Applied SC Physics GA 348ZT UT WOS:000089017200017 ER PT J AU Savvate'ev, V Friedl, J Zou, L Oldham, WJ Shinar, J AF Savvate'ev, V Friedl, J Zou, L Oldham, WJ Shinar, J TI Efficiency peaks in the transient electroluminescence of multilayer organic light-emitting devices (vol 76, pg 2170, 2000) SO APPLIED PHYSICS LETTERS LA English DT Correction 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 Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Savvate'ev, V (reprint author), Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. NR 1 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 4 PY 2000 VL 77 IS 10 BP 1560 EP 1560 DI 10.1063/1.1308052 PG 1 WC Physics, Applied SC Physics GA 348ZT UT WOS:000089017200051 ER PT J AU Wang, WD Guzei, IA Espenson, JH AF Wang, WD Guzei, IA Espenson, JH TI Hydrolysis, hydrosulfidolysis, and aminolysis of imido(methyl)rhenium complexes SO INORGANIC CHEMISTRY LA English DT Article ID TERMINAL CHALCOGENIDO COMPLEXES; MAIN-GROUP ELEMENTS; TRANSITION-METALS; MULTIPLE BONDS; METHYLTRIOXORHENIUM(VII); METHYLRHENIUM; REACTIVITY; CATALYSTS; SULFIDE; RHENIUM AB The tris(imido)methylrhenium complex CH3Re(NAd)(3) (1a, Ad = 1-adamantyl) reacts with H2O to give CH3Re-(NAd)(2)O (2a) and AdNH(2). The resulting di(imido)oxo species can further react with another molecule of H2O to generate CH3Re(NAd)O-2 (3a). The kinetics of these reactions have been studied by means of H-1 NMR and UV-vis spectroscopies. The second-order rate constant for the reaction of la with H2O at 298 K in C6H6 is 3.3 L mol(-1) s(-1), which is much larger than the value 1 x 10(-4) L mol(-1) s(-1) obtained for the reaction between CH3Re(NAr)(3) (1, Ar = 2,6-diisopropylphenyl) and H2O in CH3CN at 313 K. Both 1a and 1b react with H2S to produce the rhenium(VII) sulfide, (CH3Re(NR)(2))(2)(mu-S)(2) (4a, R = Ad; 4b, R = Ar), with second-order rate constants of 17 and 1.6 x 10(-4) L mol(-1) s(-1) in C6H6 and CH3CN, respectively. Complex 4b has been structurally characterized. The crystal data are as follows: space group C2/c, a = 30.4831 (19) Angstrom, b = 10.9766 (7) Angstrom, c = 18.1645 (11)Angstrom, beta = 108.268(1)degrees, V = 5771.5 (6) Angstrom(3), Z = 4. The reaction between CH3Re(NAr)(2)O (2b) and H2S also yields the dinuclear compound 4b. Unlike Ib, la reacts with aniline derivatives to give mixed imido rhenium complexes. 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 33 TC 6 Z9 6 U1 2 U2 7 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 SEP 4 PY 2000 VL 39 IS 18 BP 4107 EP 4112 DI 10.1021/ic0000956 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 352TQ UT WOS:000089234300022 PM 11198866 ER PT J AU Espenson, JH Yiu, DTY AF Espenson, JH Yiu, DTY TI Kinetics and mechanisms of reactions of methyldioxorhenium(V) in aqueous solutions: Dimer formation and oxygen-atom abstraction reactions SO INORGANIC CHEMISTRY LA English DT Article ID MAIN GROUP ELEMENTS; TRANSITION-METALS; MULTIPLE BONDS; COMPUTER-SIMULATION; COMPLEXES; RHENIUM(V); OXIDES; AGGREGATION; CATALYSTS; KINSIM AB The stable compound CH3ReO3 (MTO), upon treatment with aqueous hypophosphorous acid, forms a colorless metastable species designated MDO, CH3ReO2(H2O)(n) (n = 2). After standing, MDO is first converted to a yellow dimer (lambda(max) = 348 nm; epsilon = 1.3 x 10(4) L mol(-1) cm(-1)). That reaction follows second-order kinetics with k = 1.4 L mol(-1) s(-1) in 0.1 M aq trifluoromethane sulfonic acid at 298 K. Kinetics studies as functions of temperature Save Delta S-not equal = -4 +/- 15 J K-1 mol(-1) and Delta H-not equal = 71.0 +/- 4.6 M mol(-1). A much more negative value of Delta S-not equal would be expected for simple dimerization, suggesting the release of one or more molecules of water in forming the transition state. If solutions of the dimer are left for a longer period, an intense blue color results, followed by precipitation of a compound that does, even after a long time, retain the Re-CH3 bond in that aq. hydrogen peroxide generates the independently known CH3Re(O)(O-2)(2)(H2O). The blue compound may be analogous to the intensely colored purple cation [(CP*Re)(3)(mu(2)-O)(3)(mu(3)-O)(3)ReO3](+) If a pyridine N-oxide is added to the solution of the dimer, it is rapidly but not instantaneously lost at the same time that a catalytic cycle, separately monitored by NMR, converts the bulk of the PyO to Py according to this stoichiometric equation in which MDO is the active intermediate: C5H5NO + H3PO2 --> C5H5N + H3PO3 A thorough kinetic study and the analysis by mathematical and numerical simulations show that the key step is the conversion of the dimer D into a related species D* (presumably one of the two mu-oxo bonds has been broken); the rate constant is 5.6 x 10(-3) s(-1). D*; then reacts with PyO just as rapidly as MDO does. This scheme is able to account for the kinetics and other results. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 22 TC 17 Z9 17 U1 0 U2 6 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 SEP 4 PY 2000 VL 39 IS 18 BP 4113 EP 4118 DI 10.1021/ic000128h PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 352TQ UT WOS:000089234300023 PM 11198867 ER PT J AU Bond, EM Duesler, EN Paine, RT Neu, MP Matonic, JH Scott, BL AF Bond, EM Duesler, EN Paine, RT Neu, MP Matonic, JH Scott, BL TI Synthesis and molecular structure of a plutonium(IV) coordination complex: [Pu(NO3)(2){2,6-[(C6H5)(2)P(O) CH2](2)C5H3NO}(2)](NO3)(2)center dot 1.5H(2)O center dot 0.5MeOH SO INORGANIC CHEMISTRY LA English DT Article ID SOLVENT-EXTRACTION; NITRATE MEDIA; NITRIC-ACID; OXIDES; N,P,P'-TRIOXIDE; AMERICIUM(III); AM(III); PU(IV) AB The trifunctional ligand 2,6-[(C6H5)(2)P(O)CH2](2) C5H3NO (1), in a mixed EtOH/MeOH solvent system, when combined with an aqueous nitric acid solution of Pu(IV), produces a 2:1 coordination complex, [PU(1)(2)(NO3)(2)]- (NO3)(2) A single crystal of [Pu(NO3)(2){2,6-[(C6H5)(2)P(O)CH2](2)C5H3NO}(2)](NO3)(2). 1.5H(2)O . 0.5MeOH was characterized by X-ray diffraction analysis. The crystal is monoclinic, space group P2(1)/n, with a = 19.1011(9) Angstrom, b = 18.2873(9) Angstrom, c = 21.507(1) Angstrom, alpha = gamma = 90 degrees, beta = 108.63(1)degrees, and Z = 4. Two neutral ligands (1) are bonded to the Pu(IV) ion in a tridentate fashion. Two nitrate ions also occupy inner sphere coordination positions, while two additional NO3- ions reside in the outer sphere. Comparison of the solution optical absorbance and solid diffuse reflectance spectra shows the same Pu(IV) chromophore exists in both solid and solution states. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RP Paine, RT (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 25 TC 35 Z9 35 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD SEP 4 PY 2000 VL 39 IS 18 BP 4152 EP 4155 DI 10.1021/ic000146z PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 352TQ UT WOS:000089234300030 PM 11198874 ER PT J AU Xu, JD Radkov, E Ziegler, M Raymond, KN AF Xu, JD Radkov, E Ziegler, M Raymond, KN TI Plutonium(IV) sequestration: Structural and thermodynamic evaluation of the extraordinarily stable cerium(IV) hydroxypyridinonate complexes SO INORGANIC CHEMISTRY LA English DT Article ID ION SEQUESTERING AGENTS; IN-VIVO; CHELATION; LIGANDS; DTPA; 3,4,3-LIHOPO; ACTINIDES; RAT; POLYHEDRA; ANALOGS AB Ligands containing the 1-methyl-3-hydroxy-2(1H)-pyridinone group (Me-3,2-HOPO) are powerful plutonium-(IV) sequestering agents. The Ce(IV) complexes of bidentate and tetradentate HOPO ligands have been quantitatively studied as models for this sequestration. The complexes Ce(L-1)(4), Ce(L-2)(4), Ce(L-3)(2), and Ce(L-4)(2) (L-1 = Me-3,2-HOPO; L-2 = PR-Me-3,2-HOPO; L-3 = 5LI-Me-3,2-HOPO; L-4 = 5LIO-Me-3,2-HOPO) were prepared in THF solution from Ce(acac)(4) and the corresponding ligand. The complex Ce(L-4)(2) was also prepared in aqueous solution by air oxidation of the Ce(III) complex [Ce(L-4)(2)](-). Single-crystal X-ray diffraction analyses are reported for Ce(L-1)(4). 2CHCl(3) [P (1) over bar (no. 2), Z = 2, a = 9.2604(2) Angstrom, b = 12.1992(2) Angstrom, c 15.9400(2) Angstrom, alpha = 73.732(1)degrees, beta = 85.041(1)degrees, gamma = 74.454(1)degrees],Ce(L-3)(2). 2CH(3)OH [P2(1)/c (no. 14), Z = 4, a = 11.7002(2) Angstrom, b = 23.0033(4) Angstrom. c = 15.7155(2) Angstrom, beta = 96.149(1)degrees], Ce(L-4)(2). 2CH(3)OH [P (1) over bar (no. 2), Z = 2, a = 11.4347(2) Angstrom, b = 13.8008(2) Angstrom, c = 15.2844(3) Angstrom, alpha = 101.554(1)degrees, beta = 105.691(1)degrees, gamma = 106.746(1)degrees], and Ce(L-4)(2). 4H(2)O [P2(1)/c (no. 14), Z = 4, a = 11.8782(1) Angstrom, b = 22.6860(3) Angstrom, c = 15.2638(1) Angstrom, beta = 96.956(1)degrees]. A new criterion, the shape measure S. has been introduced to describe and compare the geometry of such complexes. It is defined as S = min[((1/m)Sigma(i=1)(m)(delta(i) - theta(i))(2))(1/2)], where m is the number of edges, delta(i) is the observed dihedral angle along the ith edge of delta (angle between normals of adjacent faces), theta(i) is the same angle of the corresponding ideal polytopal shape theta, and min is the minimum of all possible values. For these complexes the shape measure shows that the coordination geometry is strongly influenced by small changes in the ligand backbone or solvent. Solution thermodynamic studies determined overall formation constants (log beta) for Ce(L-2)(4), Ce(L-3)(2), and Ce(L-4)(2) of 40.9, 41.9, and 41.6, respectively. A thermodynamic cycle has been used to calculate these values from the corresponding formation constants of Ce(III) complexes and standard electrode potentials. From the formation constants and from the protonation constants of the ligands, extraordinarily high phl values for Ce(IV) are generated by these tetradentate Ligands (37.5 for Ce(L-3)(2) and 37.0 for Ce(L-4)(2)). The corresponding constants for Pu(TV) are expected to be substantially the same. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Raymond, KN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Chem, Berkeley, CA 94720 USA. FU NIEHS NIH HHS [ES02698] NR 36 TC 153 Z9 154 U1 3 U2 24 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 SEP 4 PY 2000 VL 39 IS 18 BP 4156 EP 4164 DI 10.1021/ic000063i PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 352TQ UT WOS:000089234300031 PM 11198875 ER PT J AU Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, B Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Calafiura, P Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Ciobanu, CI Clark, AG Connolly, A Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Giromini, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haas, RM Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kilminster, B Kirby, M Kirk, M Kim, BJ Kim, DH Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureaux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Lee, K Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Orejudos, W Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Pukhov, O Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Yu, Z Zanetti, A Zetti, F Zucchelli, S AF Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, B Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Calafiura, P Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Ciobanu, CI Clark, AG Connolly, A Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Giromini, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haas, RM Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kilminster, B Kirby, M Kirk, M Kim, BJ Kim, DH Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureaux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Lee, K Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Orejudos, W Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Pukhov, O Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Yu, Z Zanetti, A Zetti, F Zucchelli, S CA CDF Collaboration TI Search for second and third generation leptoquarks including production via technicolor interactions in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID = 1.8 TEV; JET CROSS-SECTIONS; HADRON COLLIDERS; 3RD-GENERATION LEPTOQUARKS; (P)OVER-BAR-P COLLISIONS; SYMMETRY-BREAKING; PAIR PRODUCTION; SIGNATURES; NUMBER; COLOR AB We report the results of a search for second and third generation leptoquarks using 88 ph(-1) of data recorded by the Collider Detector at Fermilab. Color tripler technipions, which play the role of scalar leptoquarks, are investigated due to their potential production in decays of strongly coupled color octet technirhos. Events with a signature of two heavy flavor jets and missing energy may indicate the decay of a second (third) generation leptoquark to a charm (bottom) quark and a neutrino. As the data are found to be consistent with standard model expectations, mass limits are determined. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Cambridge, MA 02139 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Oxford, Oxford OX1 3RH, England. Univ Padua, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. Acad Sinica, Inst Phys, Taipei 11529, Taiwan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Cantabria, Inst Fis Cantabria, E-39005 Santander, Spain. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Joint Inst Nucl Res, RU-141980 Dubna, Russia. Duke Univ, Durham, NC 27708 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Hiroshima Univ, Higashihiroshima 724, Japan. Univ Illinois, Urbana, IL 61801 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Kyungpook Natl Univ, Korean Hadron Collider Lab, Taegu 702701, South Korea. Seoul Natl Univ, Seoul 151742, South Korea. Sungkyunkwan Univ, Suwon 440746, South Korea. High Energy Accelerator Res Org KEK, Tsukuba, Ibaraki 305, Japan. RP Affolder, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Prokoshin, Fedor/E-2795-2012; Scodellaro, Luca/K-9091-2014; Paulini, Manfred/N-7794-2014; Introzzi, Gianluca/K-2497-2015; Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Prokoshin, Fedor/0000-0001-6389-5399; Scodellaro, Luca/0000-0002-4974-8330; Paulini, Manfred/0000-0002-6714-5787; Introzzi, Gianluca/0000-0002-1314-2580; NR 37 TC 31 Z9 32 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 SEP 4 PY 2000 VL 85 IS 10 BP 2056 EP 2061 DI 10.1103/PhysRevLett.85.2056 PG 6 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400006 ER PT J AU Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Cihangir, S Ciobanu, CI Clark, AG Connolly, A Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Dennino, M Derwent, PF Devlin, T Ditmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Giromini, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, DH Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, K Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Lee, K Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, F Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, S AF Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Cihangir, S Ciobanu, CI Clark, AG Connolly, A Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Dennino, M Derwent, PF Devlin, T Ditmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Giromini, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, G Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, DH Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, K Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Lee, K Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, F Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, P Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, S CA CDF Collaboration TI Search for new particles decaying to t(t)over-bar in p(p)over-bar collisions at root s=1.8 TeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOP-QUARK PRODUCTION; (P)OVER-BAR-P COLLISIONS; MASS; DETECTOR; PHYSICS; EVENTS; CDF AB We use 106 pb(-1) of data collected with the Collider Detector at Fermilab to search for narrow-width, vector particles decaying to a top and an antitop quark. Model independent upper limits on the cross section for narrow. vector resonances decaying to ti are presented. At the 95% confidence level, we exclude the existence of a leptophobic Z' boson in a model of top-color-assisted technicolor with mass M-Z' < 480 GeV/c(2) for natural width Gamma = 0.012M(Z)', and M-Z' < 780 GeV/c(2) for Gamma = 0.04M(Z)'. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. MIT, Cambridge, MA 02139 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Oxford, Oxford OX1 3RH, England. Univ Padua, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. Acad Sinica, Inst Phys, Taipei 11529, Taiwan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Cantabria, Inst Fis Cantabria, E-39005 Santander, Spain. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Joint Inst Nucl Res, RU-141980 Dubna, Russia. Duke Univ, Durham, NC 27708 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Hiroshima Univ, Higashihiroshima 724, Japan. Univ Illinois, Urbana, IL 61801 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Kyungpook Natl Univ, Korean Hadron Collider Lab, Taegu 702701, South Korea. Seoul Natl Univ, Seoul 151742, South Korea. Sungkyunkwan Univ, Suwon 440746, South Korea. High Energy Accelerator Res Org KEK, Tsukuba, Ibaraki 305, Japan. RP Affolder, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Scodellaro, Luca/K-9091-2014; Paulini, Manfred/N-7794-2014; Prokoshin, Fedor/E-2795-2012; Introzzi, Gianluca/K-2497-2015 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Scodellaro, Luca/0000-0002-4974-8330; Paulini, Manfred/0000-0002-6714-5787; Prokoshin, Fedor/0000-0001-6389-5399; Introzzi, Gianluca/0000-0002-1314-2580 NR 22 TC 38 Z9 38 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 SEP 4 PY 2000 VL 85 IS 10 BP 2062 EP 2067 DI 10.1103/PhysRevLett.85.2062 PG 6 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400007 ER PT J AU Jeon, S Koch, V AF Jeon, S Koch, V TI Charged particle ratio fluctuation as a signal for quark-gluon plasma SO PHYSICAL REVIEW LETTERS LA English DT Article AB In this Letter we argue that the event-by-event fluctuations of the ratio of the positively charged and the negatively charged pions provide a signal for a quark-gluon plasma. The fact that quarks carry fractional charges is ultimately responsible for this distinct signal. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Jeon, S (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 11 TC 310 Z9 314 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 SEP 4 PY 2000 VL 85 IS 10 BP 2076 EP 2079 DI 10.1103/PhysRevLett.85.2076 PG 4 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400010 ER PT J AU Budker, D Kimball, DF Rochester, SM Yashchuk, VV AF Budker, D Kimball, DF Rochester, SM Yashchuk, VV TI Nonlinear magneto-optical rotation via alignment-to-orientation conversion SO PHYSICAL REVIEW LETTERS LA English DT Article ID FARADAY-ROTATION; SPECTROSCOPY; FIELDS; LIGHT AB Nonlinear magneto-optical rotation is' investigated at high light Dowers where the rotation is significantly modified by ac Stark shifts. These shifts are shown to change the overall sign of rotation for closed F --> F + 1 transitions compared to the low light power limit. The effect is demonstrated by measurements in rubidium and density matrix calculations. The results are important fur applications of nonlinear optical rotation such as sensitive magnetometry. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Budker, D (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM budker@socrates.berkeley.edu RI Budker, Dmitry/F-7580-2016 OI Budker, Dmitry/0000-0002-7356-4814 NR 23 TC 60 Z9 60 U1 3 U2 14 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 SEP 4 PY 2000 VL 85 IS 10 BP 2088 EP 2091 DI 10.1103/PhysRevLett.85.2088 PG 4 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400013 ER PT J AU Barker, BI Polukhina, YLL Osheroff, DD Hrubesh, LW Poco, JF AF Barker, BI Polukhina, YLL Osheroff, DD Hrubesh, LW Poco, JF TI Observation of a superfluid He-3 A-B phase transition in silica aerogel SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPIN DYNAMICS; STATE AB New NMR studies of He-3 in high-porosity aerogel reveal a phase transition from an A-like to a B-lih-e phase on cooling. The evidence includes frequency shift and magnetic susceptibility data, and similar behavior is found in two quite different aerogrl samples. The A-like phase is stable: only very near to T-c. but can be supercooled to below 0.8T(c). This behavior has been seen clearly at 32- and 24-bar pressures, and the presence of negative frequency shifts suggests that an A-like phase exists near T-c at pressures as low as 12 bars in a magnetic field of 28.4 mT. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Barker, BI (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94726 USA. NR 17 TC 78 Z9 80 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 SEP 4 PY 2000 VL 85 IS 10 BP 2148 EP 2151 DI 10.1103/PhysRevLett.85.2148 PG 4 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400028 ER PT J AU Emery, VJ Fradkin, E Kivelson, SA Lubensky, TC AF Emery, VJ Fradkin, E Kivelson, SA Lubensky, TC TI Quantum theory of the smectic metal state in stripe phases SO PHYSICAL REVIEW LETTERS LA English DT Article ID ONE-DIMENSIONAL CONDUCTORS; LIQUID-CRYSTAL PHASES; LIPID COMPLEXES; SUPERCONDUCTORS AB We present a theory of the electron smectic fixed point of the stripe phases of doped layered Mott insulators. We show that in the presence of a spin gag three phases generally arise: (a) a smectic superconductor, (b) an insulating stripe crystal, and (c) a smectic metal. The latter phase is a stable two-dimensional anisotropic non-Fermi liquid. In the absence of a spin gap there is also a More conventional Fermi-liquid-like phase. The smectic superconductor and smectic metal phases (or glassy versions thereof) may have already been seen in Nd-doped La2-xSrxCuO4. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Univ Penn, Dept Phys, Philadelphia, PA 19104 USA. RP Emery, VJ (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Fradkin, Eduardo/B-5612-2013; OI Fradkin, Eduardo/0000-0001-6837-463X NR 27 TC 135 Z9 135 U1 5 U2 21 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 4 PY 2000 VL 85 IS 10 BP 2160 EP 2163 DI 10.1103/PhysRevLett.85.2160 PG 4 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400031 ER PT J AU Buczko, R Duscher, G Pennycook, SJ Pantelides, ST AF Buczko, R Duscher, G Pennycook, SJ Pantelides, ST TI Excitonic effects in core-excitation spectra of semiconductors SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-ENERGY-LOSS; X-RAY-ABSORPTION; BROKEN-SYMMETRY APPROACH; NEAR-EDGE STRUCTURE; WAVE BASIS-SET; MOLECULAR-DYNAMICS; HOLE; SPECTROSCOPY; CRYSTALLINE; SCATTERING AB Core-electron excitation spectra are used widely for structural and chemical analysis of materials, bur interpretation of the near-edge structure remains unsettled, especially for semiconductors. For the important Si L-2.3 edge, there are two mutually inconsistent interpretations, in terms of effective-mass excitons and in terms of Bloch conduction-hand final states. We report ab initio calculations and show that neither interpretation is valid and that the near-edge structure is in fact dominated by short-range electron-hole interactions even though the only bound excitons are effective-mass-like. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Buczko, R (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RI Duscher, Gerd/G-1730-2014 OI Duscher, Gerd/0000-0002-2039-548X NR 31 TC 49 Z9 49 U1 2 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD SEP 4 PY 2000 VL 85 IS 10 BP 2168 EP 2171 DI 10.1103/PhysRevLett.85.2168 PG 4 WC Physics, Multidisciplinary SC Physics GA 349VC UT WOS:000089065400033 ER PT J AU Pianetta, P Baur, K Singh, A Brennan, S Kerner, J Werho, D Wang, J AF Pianetta, P Baur, K Singh, A Brennan, S Kerner, J Werho, D Wang, J TI Application of synchrotron radiation to TXRF analysis of metal contamination on silicon wafer surfaces SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 11th International Conference on Thin Films (ICTF-11) CY AUG 30-SEP 03, 1999 CL CANCUN, MEXICO DE total reflection X-ray fluorescence; Stanford Synchrotron Radiation Laboratory; silicon wafer surfaces ID SCATTERING AB Synchrotron radiation based total reflection X-ray fluorescence (TXRF) has been shown to meet the critical needs of the semiconductor industry for the analysis of transition metal impurities on silicon wafer surfaces. The current best detection limit achieved at the Stanford Synchrotron Radiation Laboratory (SSRL) for Ni is 8 x 10(7) atoms/cm(2) which is a factor of 50 better than what can be achieved using laboratory-based sources. SSRL has established a TXRF facility which meets the cleanliness and stability requirements of the semiconductor industry. This has enabled both industrial and academic researchers to address industrially relevant problems. In addition research is being carried out for the analysis of light elements such as Al and Na. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. ARACOR, Sunnyvale, CA USA. Balazs Analyt Labs, Sunnyvale, CA USA. RP Pianetta, P (reprint author), Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NR 12 TC 34 Z9 36 U1 0 U2 1 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 SEP 3 PY 2000 VL 373 IS 1-2 BP 222 EP 226 DI 10.1016/S0040-6090(00)01139-1 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 367DF UT WOS:000090045900049 ER PT J AU Montgomery, SL Schechter, DS Lorenz, J AF Montgomery, SL Schechter, DS Lorenz, J TI Advanced reservoir characterization to evaluate carbon dioxide flooding, Spraberry trend, Midland Basin, Texas SO AAPG BULLETIN-AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS LA English DT Article AB The Spraberry trend area of west Texas, once known as the "largest uneconomical field in the world," contains as much as 10 billion bbl of original oil in place. These hydrocarbons are stratigraphically trapped in fine-grained, low-permeability and naturally fractured siltstones and sandstones deposited in submarine fans of Permian age. Despite five decades of production, including several large-scale waterflood projects, recovery from the Spraberry rarely exceeds 8-12%, Lack of scientific attention since the 1960s has resulted in most core samples suffering deterioration and loss, hampering any application of new methods for reservoir analysis. A significant new effort has been launched to correct this situation and to evaluate the efficiency and economics of using carbon dioxide (CO2) flooding to enhance recovery from Spraberry reservoirs. This effort has involved collection of new core samples, including the first horizontal cores taken in the Spraberry Eight lithofacies and six major rock types are identified, with coarse siltstones and very fine grained sandstones as the primary reservoirs. These rocks exhibit porosities and permeabilities of 7-18% and 0.3-3 md (average <1 md). Reservoir quality is Limited by grain type and size, clay content, and degree of secondary dissolution porosity. Rock-log modeling indicates a need to revise pay zone identification based on gamma-ray log data; more reliable pay zone cutoffs are shale volumes of less than 15% and effective porosities greater than 7%, Three sets of fractures were identified in the horizontal cores, with north-northeast, northeast, and east-northeast orientations. Comparisons with historical data imply that fracture spacing and orientation are localized both areally and in individual reservoir units. Engineering analyses of Spraberry core indicate that the oil-saturated matrix is weakly water wet. Displacement of matrix oil by water imbibition is an important process in recovery during water injection. Laboratory study of CO2 gravity drainage in Spraberry core suggests that significant additional oil can be recovered in this maimer; however, the degree to which this can be achieved at the field scale, within a time frame enhancing to profitability, remains undetermined. Future work will seek to resolve this question by implementing a pilot CO2 injection program in the E. T. O'Daniel unit, Together, these new studies will provide an important base of data for future evaluations of Spraberry potential. C1 New Mexico Inst Min & Technol, New Mexico Petr Recovery Res Ctr, Socorro, NM 87801 USA. Sandia Natl Lab, Dept Geophys, Albuquerque, NM 87185 USA. RP Montgomery, SL (reprint author), 1511 18th Ave E, Seattle, WA 98112 USA. NR 27 TC 3 Z9 4 U1 0 U2 2 PU AMER ASSOC PETROLEUM GEOLOGIST PI TULSA PA 1444 S BOULDER AVE, PO BOX 979, TULSA, OK 74101 USA SN 0149-1423 J9 AAPG BULL JI AAPG Bull.-Am. Assoc. Petr. Geol. PD SEP PY 2000 VL 84 IS 9 BP 1247 EP 1273 PG 27 WC Geosciences, Multidisciplinary SC Geology GA 351UZ UT WOS:000089177700001 ER PT J AU Kolda, TG O'Leary, DP AF Kolda, TG O'Leary, DP TI Algorithm 805: Computation and uses of the semidiscrete matrix decomposition SO ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE LA English DT Article DE algorithms; singular value decomposition; semidiscrete decomposition; latent semantic indexing; compression; matrix decomposition AB We present algorithms for computing a semidiscrete approximation to a matrix in a weighted norm, with the Frobenius norm as a special case. The approximation is formed as a weighted sum of outer products of vectors whose elements are +/-1 or 0, so the storage required by the approximation is quite small. We also present a related algorithm for approximation of a tensor. Applications of the algorithms are presented to data compression, filtering, and information retrieval; software is provided in C and in Matlab. C1 Sandia Natl Labs, Computat Sci & Math Res Dept, Livermore, CA 94551 USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. Univ Maryland, Inst Adv Comp Studies, College Pk, MD 20742 USA. RP Kolda, TG (reprint author), Sandia Natl Labs, Computat Sci & Math Res Dept, Livermore, CA 94551 USA. RI Kolda, Tamara/B-1628-2009 OI Kolda, Tamara/0000-0003-4176-2493 NR 11 TC 10 Z9 11 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0098-3500 J9 ACM T MATH SOFTWARE JI ACM Trans. Math. Softw. PD SEP PY 2000 VL 26 IS 3 BP 415 EP 435 DI 10.1145/358407.358424 PG 21 WC Computer Science, Software Engineering; Mathematics, Applied SC Computer Science; Mathematics GA 396EJ UT WOS:000166623100007 ER PT J AU Click, DR Scott, BL Watkin, JG AF Click, DR Scott, BL Watkin, JG TI Tris[(pentafluorophenyl)trimethylsilylamido](tetrahydrofuran)samarium(II I) SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Article ID COMPLEXES; CHEMISTRY; LIGANDS; REACTIVITY AB In the title complex, [Sm(C9H9F5NSi)(3)(C4H8O)], the Sm metal center is coordinated in a highly distorted tetrahedral geometry by the three N atoms of the amido ligands and by the O atom of the tetrahydrofuran ligand. Principal bond lengths include: Sm-N 2.299 (4), 2.339 (4) and 2.366 (4) Angstrom, and Sm-O 2.446 (3) Angstrom, close Sm ... F contacts of 2.536 (3) and 2.556 (3) Angstrom, and an `agostic' Sm ... C interaction of 3.154 (4) Angstrom. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. RP Watkin, JG (reprint author), Univ Calif Los Alamos Natl Lab, CST-18,MS J514, Los Alamos, NM 87545 USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 14 TC 4 Z9 4 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD SEP PY 2000 VL 56 BP 1095 EP 1096 DI 10.1107/S0108270100008775 PN 9 PG 2 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 353WN UT WOS:000089298600016 ER PT J AU Bryan, JC Sachleben, RA AF Bryan, JC Sachleben, RA TI Benzo-cis-cyclohexano-14-crown-4 and its lithium thiocyanate complex SO ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY LA English DT Article ID STRUCTURAL CRITERIA; SELECTIVE LIGANDS; RATIONAL DESIGN; CROWN-ETHERS; ALKALI AB The structures of a 14-crown-4 ether containing both benzo and cyclohexano substituents, 2,6,13,17-tetraoxatricyclo[16.4.0.0 (7,12)]docosa-1(18),19,21-triene, C18H26O4, and its lithium complex, [2,6,13,17-tetraoxatricyclo[16.4.0.0 7,12]docosa-1(18),19,21-triene-kappa(4)O](thiocyanato-N)lithium(I), [Li(NCS)(C18H26O4)], are presented. The conformation of the free crown, (I), is not preorganized for cation binding, as its donor dipoles are oriented towards opposite sides of the crown ring. The Li + -crown complex, (II), exhibits two formula units in the asymmetric unit. The binding conformation observed in (II) does not completely reorient the dipoles to one point, resulting in a long Li-O bond length [2.068 (5) and 2.073 (5) Angstrom]. 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. EM bryanjc@ornl.gov NR 15 TC 1 Z9 1 U1 1 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0108-2701 EI 1600-5759 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Struct. Chem. PD SEP PY 2000 VL 56 BP 1104 EP 1106 DI 10.1107/S0108270100009033 PN 9 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 353WN UT WOS:000089298600019 ER PT J AU Sui, HX Walian, PJ Tang, G Oh, A Jap, BK AF Sui, HX Walian, PJ Tang, G Oh, A Jap, BK TI Crystallization and preliminary X-ray crystallographic analysis of water channel AQP1 SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID CHIP28; AQUAPORIN-1; PROTEIN; PURIFICATION; EXPRESSION AB Aquaporin-1 (AQP1), a water channel from bovine red blood cells has been deglycosylated, purified to homogeneity and crystallized in a form suitable for X-ray crystallographic study. Crystals are grown using polyethylene glycol as precipitant and belong to the tetragonal space group I422, with unit-cell parameters a = b = 93.4, c = 180.4 Angstrom. The crystals diffract beyond 2.2 Angstrom resolution. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Jap, BK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. NR 20 TC 13 Z9 16 U1 0 U2 3 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 SEP PY 2000 VL 56 BP 1198 EP 1200 DI 10.1107/S0907444900008143 PN 9 PG 3 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 347AM UT WOS:000088904100020 PM 10957645 ER PT J AU Maziasz, PJ AF Maziasz, PJ TI Fuel cell future! SO ADVANCED MATERIALS & PROCESSES LA English DT Editorial Material C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0882-7958 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD SEP PY 2000 VL 158 IS 3 BP 8 EP 8 PG 1 WC Materials Science, Multidisciplinary SC Materials Science GA 354UN UT WOS:000089348200002 ER PT J AU Butterweck-Dempewolf, G Schuler, C Vezzu, G Reineking, A Huet, C Tymen, C Strong, JC Knutson, EO Vargas, A AF Butterweck-Dempewolf, G Schuler, C Vezzu, G Reineking, A Huet, C Tymen, C Strong, JC Knutson, EO Vargas, A TI Intercomparison of approximation algorithms for the determination of the size distribution of the "unattached" fraction of radon progeny SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID DIFFUSION BATTERY DATA; DECAY PRODUCTS; RECONSTRUCTION; INVERSION; EXPOSURE; THORON AB Starting in 1996, nonlinear approximation algorithms used for the determination of size distributions of "unattached" radon progeny from measurements made with diffusional size classification instruments were compared. Seven participants tone American and six European) took part using various techniques (Simplex, Expectation Maximization, Extreme Value Estimation, Twomey, and Random Walk) which are widely used for this type of work. Simulated input data was supplied to the participants. Their output data indicated that the quality of the results varied according to the algorithm used. This was particularly the case when retrieving parameters from binodal distributions where large inaccuracies were shown. Variations were found between participants using basically identical algorithms. The influence of measurement uncertainties was investigated and indicated a serious reduction of retrieval accuracy, especially for algorithms with better than average performance for precise data. This work suggests that when high precision results are required, a random walk algorithm should be used and attention should be paid to reducing errors in the input penetration data. C1 Paul Scherrer Inst, Div Radiat Protect & Waste Management, CH-5232 Villigen, Switzerland. Univ Gottingen, Med Forsch, D-37077 Gottingen, Germany. Univ Gottingen, Isotopenlab Biol, D-37077 Gottingen, Germany. Univ Bretagne Occidentale, Fac Sci, Lab Rech Appliquees Atmosphere Hydrosphere, F-29285 Brest, France. AEA Technol, Biomed Res Dept, Didcot OX11 0RA, Oxon, England. US Dept Energy, Environm Measurements Lab, New York, NY 10014 USA. Univ Politecn Catalunya, Inst Tecniques Energetiques, E-08028 Barcelona, Spain. RP Butterweck-Dempewolf, G (reprint author), Paul Scherrer Inst, Div Radiat Protect & Waste Management, CH-5232 Villigen, Switzerland. RI Vargas, Arturo/F-5389-2016 OI Vargas, Arturo/0000-0002-2576-9671 NR 27 TC 1 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD SEP PY 2000 VL 33 IS 3 BP 261 EP 273 DI 10.1080/027868200416240 PG 13 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 350KM UT WOS:000089099900005 ER PT J AU Stanley, SA Sarkar, S AF Stanley, SA Sarkar, S TI Influence of nozzle conditions and discrete forcing on turbulent planar jets SO AIAA JOURNAL LA English DT Article ID FINITE-DIFFERENCE SCHEMES; DEPENDENT BOUNDARY-CONDITIONS; HYPERBOLIC SYSTEMS; SIMULATIONS; FLOWS; TRANSITION; LAYERS AB Planar turbulent jets are of great interest in a broad range of engineering applications such as combustion, propulsion, and environmental hows. The influence of the turbulence intensity at the inflow and the shear-layer momentum thickness, as well as the effects of discrete forcing on the initial development of the jet, are studied computationally. It is found that the inflow fluctuation intensity and shear-layer momentum thickness have significant impact on the initial growth of the jet. Higher fluctuation intensity and thinner shear layers lead to more rapid growth of the jet with an asymptotic approach of the centerline turbulent kinetic energy to the self-similar values. The influence of the shear-layer thickness suggests a strong dependence of the initial growth on the shear-layer instabilities near the nozzle. Two-dimensional discrete forcing enhances the growth and two-dimensionality of the large-scale structures in the near field of the jet. However, significant three-dimensional small-scale structures coexist with the large-scale structures. The influence of the forcing is rapidly lost downstream as the large-scale structures break down. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Stanley, SA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 40 TC 29 Z9 30 U1 0 U2 5 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 SEP PY 2000 VL 38 IS 9 BP 1615 EP 1623 DI 10.2514/2.1144 PG 9 WC Engineering, Aerospace SC Engineering GA 350AE UT WOS:000089077400015 ER PT J AU Post-Zwicker, A AF Post-Zwicker, A TI Fusion information on the Web SO AMERICAN JOURNAL OF PHYSICS LA English DT Letter C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Post-Zwicker, A (reprint author), Princeton Univ, Plasma Phys Lab, James Forrestal Campus,POB 451, Princeton, NJ 08543 USA. NR 1 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 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD SEP PY 2000 VL 68 IS 9 BP 788 EP 788 DI 10.1119/1.1304910 PG 1 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 347HL UT WOS:000088922400012 ER PT J AU Okamoto, CT Duman, JG Tyagarajan, K McDonald, KL Jeng, YY McKinney, J Forte, TM Forte, JG AF Okamoto, CT Duman, JG Tyagarajan, K McDonald, KL Jeng, YY McKinney, J Forte, TM Forte, JG TI Clathrin in gastric acid secretory (parietal) cells: biochemical characterization and subcellular localization SO AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY LA English DT Article DE hydrogen-potassium-adenosinetriphosphatase; apical membrane recycling; tubulovesicles; dynamin; gastric microsomes ID 2-DIMENSIONAL GEL-ELECTROPHORESIS; POLARIZED MDCK CELLS; COATED VESICLES; LIGHT-CHAINS; MEDIATED ENDOCYTOSIS; RECYCLING HYPOTHESIS; DISTINCT FUNCTIONS; HCL SECRETION; OXYNTIC CELLS; H+/K+-ATPASE AB Clathrin from H-K-ATPase-rich membranes derived from the tubulovesicular compartment of rabbit and hog gastric acid secretory (parietal) cells was characterized biochemically, and the subcellular localization of membrane-associated clathrin in parietal cells was characterized by immunofluorescence, electron microscopy, and immunoelectron microscopy. Clathrin from H-K-ATPase-rich membranes was determined to be comprised of conventional clathrin heavy chain and a predominance of clathrin light chain A. Clathrin and adaptors could be induced to polymerize quantitatively in vitro, forming 120-nm-diameter basketlike structures. In digitonin-permeabilized resting parietal cells, the intracellular distribution of immunofluorescently labeled clathrin was suggestive of labeling of the tubulovesicular compartment. Clathrin was also unexpectedly localized to canalicular (apical) membranes, as were alpha-adaptin and dynamin, suggesting that this membrane domain of resting parietal cells is endocytotically active. At the ultrastructural level, clathrin was immunolocalized to canalicular and tubulovesicular membranes. H-K-ATPase was immunolocalized to the same membrane domains as clathrin but did not appear to be enriched at the specific subdomains that were enriched in clathrin. Finally, in immunofluorescently labeled primary cultures of parietal cells, in contrast to the H-K-ATPase, intracellular clathrin was found not to translocate to the apical membrane on secretagogue stimulation. Taken together, these biochemical and morphological data provide a framework for characterizing the role of clathrin in the regulation of membrane trafficking from tubulovesicles and at the canalicular membrane in parietal cells. C1 Univ So Calif, Sch Pharm, Dept Pharmaceut Sci, Los Angeles, CA 90089 USA. Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Electron Microscope Lab, Berkeley, CA 94720 USA. RP Okamoto, CT (reprint author), Univ So Calif, Sch Pharm, Dept Pharmaceut Sci, 1985 Zonal Ave, Los Angeles, CA 90089 USA. FU NCRR NIH HHS [RR-08282, RR-01614]; NIDDK NIH HHS [DK-51588] NR 56 TC 28 Z9 28 U1 0 U2 2 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0363-6143 J9 AM J PHYSIOL-CELL PH JI Am. J. Physiol.-Cell Physiol. PD SEP PY 2000 VL 279 IS 3 BP C833 EP C851 PG 19 WC Cell Biology; Physiology SC Cell Biology; Physiology GA 344EQ UT WOS:000088745000029 PM 10942733 ER PT J AU Hanchar, JM Nagy, KL Fenter, P Finch, RJ Beno, DJ Sturchio, NC AF Hanchar, JM Nagy, KL Fenter, P Finch, RJ Beno, DJ Sturchio, NC TI Quantification of minor phases in growth kinetics experiments with powder X-ray diffraction SO AMERICAN MINERALOGIST LA English DT Article ID SOLUTION SATURATION STATE; PRECIPITATION KINETICS; QUANTITATIVE INTERPRETATION; GIBBSITE; 80-DEGREES-C; DISSOLUTION; KAOLINITE; CALCITE; SCATTERING; DEPENDENCE AB Minor amounts of clay minerals precipitated from aqueous solution can be rapidly identified and quantified in a mineral mixture with powder X-ray diffraction using a rotating-anode source and a position-sensitive detector. For the case of gibbsite precipitated on a kaolinite powder substrate we demonstrate a simple method having a minimum detection limit of 0.1 wt%, using pure gibbsite as the intensity reference in mechanical mixtures of gibbsite and kaolinite. The amount of gibbsite precipitated onto kaolinite at 80 degrees C, pH 3 is higher when determined from solution chemistry than from the X-ray method, and the difference in amounts increases with increasing Al concentration in solution. This discrepancy can be explained by assuming that a fraction of the precipitated material is effectively invisible to the X-ray diffraction technique, either due to a small diffracting domain size along the gibbsite [001] direction or formation of an Al-phase that is amorphous to X-rays. This method should be generally useful for a range of mineral mixtures where at least one intense reflection for the phase of interest is not obscured. The ability to identify, characterize, and quantify trace phases by X-ray diffraction, especially when combined with surface analysis by electron or atomic force imaging, is an important complement to the conventional approach of monitoring solution composition in growth kinetics experiments. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. RP Hanchar, JM (reprint author), George Washington Univ, Dept Earth & Environm Sci, Washington, DC 20052 USA. EM sturchio@anl.gov RI Finch, Robert/D-9553-2013 OI Finch, Robert/0000-0001-9342-5574 NR 34 TC 6 Z9 6 U1 0 U2 3 PU MINERALOGICAL SOC AMER PI CHANTILLY PA 3635 CONCORDE PKWY STE 500, CHANTILLY, VA 20151-1125 USA SN 0003-004X EI 1945-3027 J9 AM MINERAL JI Am. Miner. PD SEP PY 2000 VL 85 IS 9 BP 1217 EP 1222 PG 6 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 350NV UT WOS:000089108800015 ER PT J AU Beyer, WA AF Beyer, WA TI Untitled SO AMERICAN SCIENTIST LA English DT Letter C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. RP Beyer, WA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 USA SN 0003-0996 J9 AM SCI JI Am. Scientist PD SEP-OCT PY 2000 VL 88 IS 5 BP 381 EP 381 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 345BZ UT WOS:000088796700006 ER PT J AU Stevens, FJ AF Stevens, FJ TI Four structural risk factors identify most fibril-forming kappa light chains SO AMYLOID-INTERNATIONAL JOURNAL OF EXPERIMENTAL AND CLINICAL INVESTIGATION LA English DT Article DE fibril formation; stability; somatic mutation; variable domain; myelin protein zero ID BENCE-JONES-PROTEIN; AL-AMYLOID PROTEIN; VARIABLE REGION; DEPOSITION DISEASE; MOLECULAR ANALYSIS; TERTIARY STRUCTURE; FOLDING STABILITY; FANCONIS-SYNDROME; MULTIPLE-MYELOMA; DISULFIDE BRIDGE AB Antibody light chains (LCs) comprise the most structurally diverse family of proteins involved in amyloidosis. Many antibody LCs incorporate structural features that impair their stability and solubility, leading to their assembly into fibrils and to their subsequent pathological deposition when produced in excess during multiple myeloma and primary amyloidosis. The particular amino acid variations in antibody LCs that account for fibril formation and amyloidogenesis have not been identified. This study focuses on amyloidogenesis within the kappa 1 family of human LCs. Reanalysis of the current database of primary structures of proteins from more than 100 patients who produced kappa 1 LCs, 37 of which were amyloidogenic, reveals apparent structural features that may contribute to amyloidosis. These features include loss of conserved residues or the gain of particular residues through mutation at sites involving a repertoire of approximately 20% of the amino acid positions in the light chain variable domain (V-L). Moreover, 80% of all kappa 1 amyloidogenic V(L)s are identifiable by the presence of at least one of three single-site substitutions or the acquisition of an N-linked glycosylation site through mutations. These findings suggest that it is feasible to predict fibril propensity by analysis of primary structure. C1 Argonne Natl Lab, Div Biosci, Argonne, IL 60439 USA. RP Stevens, FJ (reprint author), Argonne Natl Lab, Div Biosci, 9700 S Cass Ave, Argonne, IL 60439 USA. FU NIDDK NIH HHS [DK43757] NR 66 TC 57 Z9 59 U1 0 U2 6 PU PARTHENON PUBLISHING GROUP PI CARNFORTH LANCASHIRE PA CASTERTON HALL, CARNFORTH LANCASHIRE LA6 2LA, ENGLAND SN 1350-6129 J9 AMYLOID JI Amyloid-Int. J. Exp. Clin. Investig. PD SEP PY 2000 VL 7 IS 3 BP 200 EP 211 DI 10.3109/13506120009146835 PG 12 WC Biochemistry & Molecular Biology; Medicine, General & Internal; Medicine, Research & Experimental SC Biochemistry & Molecular Biology; General & Internal Medicine; Research & Experimental Medicine GA 359FH UT WOS:000089600500006 PM 11019861 ER PT J AU Krahmer, MT Walters, JJ Fox, KF Fox, A Creek, KE Pirisi, L Wunschel, DS Smith, RD Tabb, DL Yates, JR AF Krahmer, MT Walters, JJ Fox, KF Fox, A Creek, KE Pirisi, L Wunschel, DS Smith, RD Tabb, DL Yates, JR TI MS for identification of single nucleotide polymorphisms and MS/MS for discrimination of isomeric PCR products SO ANALYTICAL CHEMISTRY LA English DT Article ID TANDEM MASS-SPECTROMETRY; CHAIN-REACTION PRODUCTS; ELECTROSPRAY-IONIZATION; HUMAN-GENOME; DELAYED EXTRACTION; NUCLEIC-ACIDS; DNA FRAGMENTS; OLIGONUCLEOTIDES; RESOLUTION; 50-MER AB ESI (electrospray ionization) MS and tandem mass spectrometry (MS/MS) were used for the analysis of single nucleotide polymorphisms (SNPs) and more complex genetic variations. Double-stranded (ds) PCR products were studied. PCR products of the proline [5'-x(G(17))- alpha(C-38) x-3'] and arginine variants [(5'-x(G(17))-x(G(38))x-3'] of the p53 gene are distinguished by an SNP (cytosine or guanine) and were discriminated using both quadrupole and quadrupole ion trap MS analysis. A 69 bp arginine mutant PCR product [5)-x(C-17)-x(G(38))x-3'] With a negating switch has the same mass as the proline variant but was readily distinguishable on ion trap MS/MS analysis; fragments containing the mutation site, but not the polymorphism, were identified. The 69 bp PCR products were restriction-enzyme-digested, to create 43 bp fragments. ESI quadrupole ion trap MS/MS analysis of the 43 bp product-ion spectra readily demonstrated both polymorphism and negating switch sites. MS and MS/MS are powerful and complementary techniques for analysis of DNA. MS can readily distinguish SNPs but MS/MS is required to differentiate isomeric PCR products (same nucleotide composition but different sequence). C1 Univ S Carolina, Sch Med, Dept Microbiol & Immunol, Columbia, SC 29208 USA. Univ S Carolina, Sch Med, Dept Pathol, Columbia, SC 29208 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Washington, Dept Mol Biotechnol, Seattle, WA 98195 USA. RP Univ S Carolina, Sch Med, Dept Microbiol & Immunol, Columbia, SC 29208 USA. EM Afox@med.ac.edu RI Wunschel, David/F-3820-2010; Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 FU NHGRI NIH HHS [R21 HG01810-01] NR 42 TC 36 Z9 38 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD SEP 1 PY 2000 VL 72 IS 17 BP 4033 EP 4040 DI 10.1021/ac000142b PG 8 WC Chemistry, Analytical SC Chemistry GA 351VJ UT WOS:000089178600019 PM 10994962 ER PT J AU Bruckner-Lea, CJ Stottlemyre, MS Holman, DA Grate, JW Brockman, FJ Chandler, DP AF Bruckner-Lea, CJ Stottlemyre, MS Holman, DA Grate, JW Brockman, FJ Chandler, DP TI Rotating rod renewable microcolumns for automated, solid-phase DNA hybridization studies SO ANALYTICAL CHEMISTRY LA English DT Article ID SURFACE-PLASMON RESONANCE; FLOW-INJECTION ABSORPTIOMETRY; BIOLIGAND INTERACTION ASSAY; SEQUENTIAL INJECTION; OLIGONUCLEOTIDE ARRAYS; FUNCTIONAL ASSAYS; NUCLEIC-ACIDS; SEPARATION; SENSOR; SYSTEM AB The development of a new temperature-controlled renewable microcolumn now cell, for solid-phase nucleic acid hybridization in an automated sequential injection system is described. The now cell included a stepper motor-driven rotating rod with the working end cut to a 45 degrees angle. In one position, the end of the rod prevented passage of microbeads while allowing fluid now; rotation of the rod by 180 degrees releases the beads. This system was used to rapidly test many hybridization and elution protocols to examine the temperature and solution conditions required for sequence-specific nucleic acid hybridization. Target nucleic acids labeled with a near-infrared fluorescent dye were detected immediately postcolumn during all column perfusion and elution steps using a now-through fluorescence detector. Temperature control of the column and the presence of Triton X-100 surfactant were critical for specific hybridization. Perfusion of the column with complementary oligonucleotide (200 mu L, 10 nM) resulted in hybridization with 8% of the DNA binding sites on the microbeads with a solution residence time of less than 1 s and a total sample perfusion time of 40 s. The use of the renewable column system for detection of an unlabeled PCR product in a sandwich assay was also demonstrated. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Bruckner-Lea, CJ (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. EM cindy.bruckner-lea@pnl.gov; dp.chandler@pnl.gov NR 43 TC 26 Z9 26 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD SEP 1 PY 2000 VL 72 IS 17 BP 4135 EP 4141 DI 10.1021/ac000246m PG 7 WC Chemistry, Analytical SC Chemistry GA 351VJ UT WOS:000089178600032 PM 10994975 ER PT J AU Boralv, E Eglitis, P Opgenoorth, HJ Donovan, E Reeves, G Stauning, P AF Boralv, E Eglitis, P Opgenoorth, HJ Donovan, E Reeves, G Stauning, P TI The dawn and dusk electrojet response to substorm onset SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article; Proceedings Paper CT 9th International EISCAT Workshop CY SEP 06-10, 1999 CL WERNIGERODE, GERMANY DE ionosphere; auroral ionosphere; electric fields and currents; magnetospheric physics; storms and substorms ID MAGNETOSPHERIC SUBSTORMS; AURORAL ELECTROJET; PI-2 PULSATIONS; VIEW; TIME AB We have investigated the time delay between substorm onset and related reactions in the dawn and dusk ionospheric electrojets, clearly separated from the nightside located substorm current wedge by several hours in MLT. We looked for substorm onsets occurring over Greenland, where the onset was identified by a LANL satellite and DMI magnetometers located on Greenland. With this setup the MARIA magnetometer network was located at dusk, monitoring the eastward electrojet, and the IMAGE chain at dawn, for the westward jet. In the first few minutes following substorm onset, sudden enhancements of the electrojets were identified by looking for rapid changes in magnetograms. These results show that the speed of information transfer between the region of onset and the dawn and dusk ionosphere is very high. A number of events where the reaction seemed to preceed the onset were explained by either unfavorable instrument locations, preventing proper onset timing, or by the inner magnetosphere's reaction to the Earthward fast flows from the near-Earth neutral line model. Case studies with ionospheric coherent (SuperDARN) and incoherent (EISCAT) radars have been performed to see whether a convection-induced electric field or enhanced conductivity is the main agent for the reactions in the electrojets. The results indicate an imposed electric field enhancement. C1 Swedish Inst Space Phys, S-75121 Uppsala, Sweden. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Danish Meterol Inst, Solar Terr Phys Div, DK-2100 Copenhagen, Denmark. RP Boralv, E (reprint author), Swedish Inst Space Phys, Box 537, S-75121 Uppsala, Sweden. OI Donovan, Eric/0000-0002-8557-4155 NR 28 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD SEP PY 2000 VL 18 IS 9 SI SI BP 1097 EP 1107 DI 10.1007/s00585-000-1097-4 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 362CV UT WOS:000089761800012 ER EF