FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Gough, B Onogi, T Simone, J AF Gough, B Onogi, T Simone, J TI Effects of improvement: f(pi) and m(q) SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA ID QCD AB We present a study of the effects of improvement on light-quark physics using the Fermilab formalism. The calculations were performed at three different lattice spacings, with the SW action and traditional Wilson action (both tadpole improved). We find that O(a) effects for the decay constant f(pi) and quark mass m(q) can be successfully removed using the tadpole-improved SW action in the light-quark regime. RP FERMILAB NATL ACCELERATOR LAB, THEORET PHYS GRP, POB 500, BATAVIA, IL 60510 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 333 EP 336 DI 10.1016/0920-5632(96)00068-0 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300043 ER PT J AU Kim, S Ohta, S AF Kim, S Ohta, S TI Light hadron masses with 4-GeV cutoff and L=2.4 fm SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA ID QCD AB We discuss preliminary results from our quenched light hadron mass calculation on a 48(3) x 64 lattice at the coupling of beta = 6.5. Staggered quarks with masses of m(q) = 0.01, 0.005, 0.0025 and 0.00125 are used. C1 ARGONNE NATL LAB, ARGONNE, IL 60439 USA. RIKEN, INST PHYS & CHEM RES, WAKO, SAITAMA 35101, JAPAN. RP SEOUL NATL UNIV, CTR THEORET PHYS, SEOUL 151, SOUTH KOREA. NR 6 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 350 EP 353 DI 10.1016/0920-5632(96)00071-0 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300046 ER PT J AU Burden, CJ Qian, L Roberts, CD Tandy, PC Thomson, MJ AF Burden, CJ Qian, L Roberts, CD Tandy, PC Thomson, MJ TI Separable approximation to the Bethe-Salpeter equation in QCD SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA ID BOUND-STATES AB We calculate the mass spectrum and decay constants of the pseudoscalar meson octet, and mass spectrum of the vector meson octet from a separable approximation to the Bethe-Salpeter equation. In the model, quark propagators inspired by earlier studies of QCD Dyson-Schwinger equations are taken as the only input. C1 KENT STATE UNIV,DEPT PHYS,KENT,OH 44242. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. UNIV MELBOURNE,SCH PHYS,PARKVILLE,VIC 3052,AUSTRALIA. RP Burden, CJ (reprint author), AUSTRALIAN NATL UNIV,RES SCH PHYS SCI & ENGN,DEPT THEORET PHYS,CANBERRA,ACT 0200,AUSTRALIA. RI Burden, Conrad/D-5556-2016; OI Burden, Conrad/0000-0003-0015-319X; Roberts, Craig/0000-0002-2937-1361 NR 16 TC 1 Z9 1 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 MAR PY 1996 SU 47 BP 362 EP 365 DI 10.1016/0920-5632(96)00074-6 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300049 ER PT J AU Mandula, JE Ogilvie, MC AF Mandula, JE Ogilvie, MC TI Renormalization of the lattice heavy quark classical velocity SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA ID MESONS; DECAYS AB In the lattice formulation of the Heavy Quark Effective Theory (LHQET), the ''classical velocity'' nu becomes renormalized. The origin of this renormalization is the reduction of Lorentz (or O(4)) invariance to (hyper)cubic invariance. The renormalization is finite and depends on the form of the decretization of the reduced heavy quark Dirac equation. For the Forward Time - Centered Space discretization, the renormalization is computed both perturbatively, to one loop, and non-perturbatively using two ensembles of lattices, one at beta = 5.7 and the other at beta = 6.1 The estimates agree, and indicate that for small classical velocities, <(nu)over right arrow> is reduced by about 25-30%. C1 WASHINGTON UNIV, DEPT PHYS, ST LOUIS, MO 63130 USA. RP US DOE, DIV HIGH ENERGY PHYS, WASHINGTON, DC 20585 USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 405 EP 408 DI 10.1016/0920-5632(96)00083-7 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300058 ER PT J AU Kim, S AF Kim, S TI Decay rates of various bottomonium systems SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA AB Using the Bodwin-Braaten-Lepage factorization theorem in heavy quarkonium decay and production processes, we calculated matrix elements associated with S- and P-wave bottomonium decays via lattice QCD simulation methods. In this work, we report preliminary results on the operator matching between the lattice expression and the continuum expression at one loop level. Phenomenological implications are discussed using these preliminary <(MS)over bar> matrix elements. RP Kim, S (reprint author), ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 4 TC 4 Z9 4 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 MAR PY 1996 SU 47 BP 437 EP 440 DI 10.1016/0920-5632(96)00092-8 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300065 ER PT J AU Bernard, C Blum, T De, A DeGrand, T DeTar, C Gottlieb, S Heller, UM Hetrick, J Ishizuka, N Labrenz, J Rummukainen, K Soni, A Sugar, R Toussaint, D Wingate, M AF Bernard, C Blum, T De, A DeGrand, T DeTar, C Gottlieb, S Heller, UM Hetrick, J Ishizuka, N Labrenz, J Rummukainen, K Soni, A Sugar, R Toussaint, D Wingate, M TI f(B) quenched and unquenched SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA AB Results for f(B), f(Bs), f(D), f(Ds), and their ratios are presented. High statistics quenched runs at beta = 5.7, 5.85, 6.0, and 6.3, plus a run still in progress at beta = 6.52 make possible a preliminary extrapolation to the continuum. The data allows good control of all systematic errors except for quenching, although not all of the error estimates have been finalized. Results from configurations which include effects of dynamical quarks show a significant deviation from the quenched results and make possible a crude estimate of the quenching error. C1 UNIV ARIZONA, DEPT PHYS, TUCSON, AZ 85721 USA. UNIV COLORADO, DEPT PHYS, BOULDER, CO 80309 USA. UNIV UTAH, DEPT PHYS, SALT LAKE CITY, UT 84112 USA. INDIANA UNIV, DEPT PHYS, BLOOMINGTON, IN 47405 USA. FLORIDA STATE UNIV, SUPERCOMP COMPUTAT RES INST, TALLAHASSEE, FL 32306 USA. UNIV WASHINGTON, DEPT PHYS, SEATTLE, WA 98195 USA. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. UNIV CALIF SANTA BARBARA, DEPT PHYS, SANTA BARBARA, CA 93106 USA. RP WASHINGTON UNIV, DEPT PHYS, ST LOUIS, MO 63130 USA. OI Hetrick, James/0000-0002-0740-2251; Heller, Urs M./0000-0002-2780-5584; Wingate, Matthew/0000-0001-6568-988X; DeTar, Carleton/0000-0002-0216-6771; Rummukainen, Kari/0000-0003-2266-4716 NR 9 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 459 EP 462 DI 10.1016/0920-5632(96)00101-6 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300070 ER PT J AU Gupta, R Bhattacharya, T AF Gupta, R Bhattacharya, T TI Status report on weak matrix element calculations SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA ID PERTURBATION-THEORY; CHIRAL LOGARITHMS AB This talk presents results of weak matrix elements calculated from simulations done on 170 32(3) x 64 lattices at beta = 6.0 using quenched Wilson fermions. We discuss the extraction of pseudoscalar decay constants f(pi), f(K), f(D), and f(Ds), the form-factors for the rare decay B --> K*gamma, and the matrix elements of the Li-fermion operators relevant to B-K, B-7, B-8. We present an analysis of the various sources of systematic errors, and show that these are now much larger than the statistical errors for each of these observables. Our main results are f(D) = 186(29) MeV, f(Ds) = 224(16)MeV, T-1 = T-2 = 0.24(1), B-K(NDR, 2 GeV) = 0.67(9), and B-8(NDR, 2 GeV) = 0.81(1). RP LOS ALAMOS NATL LAB, GRP T8, MS B285, LOS ALAMOS, NM 87545 USA. RI Bhattacharya, Tanmoy/J-8956-2013 OI Bhattacharya, Tanmoy/0000-0002-1060-652X NR 16 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 473 EP 480 DI 10.1016/0920-5632(96)00104-1 PG 8 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300073 ER PT J AU Bhattacharya, T Gupta, R AF Bhattacharya, T Gupta, R TI Lattice analysis of semi-leptonic form factors SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA AB We present preliminary results from simulations done on 170 32(3) x 64 lattices at beta = 6.0 using quenched Wilson fermions. This talk focuses on the Q(2) behavior of the form-factors, extrapolation in quark masses, dependence on renormalization scheme, and comparison with heavy-quark effective theory (HQET). Even though we cannot estimate errors due to quenching and discretization, our results are consistent with experimental results for D decays. We present results for the Isgur-Wise function and estimate xi'(w = 1) = 0.97(6). RP LOS ALAMOS NATL LAB, GRP T8, MS B285, LOS ALAMOS, NM 87545 USA. RI Bhattacharya, Tanmoy/J-8956-2013 OI Bhattacharya, Tanmoy/0000-0002-1060-652X NR 6 TC 10 Z9 10 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 481 EP 484 DI 10.1016/0920-5632(96)00105-3 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300074 ER PT J AU Bhattacharya, T Gupta, R Sharpe, S AF Bhattacharya, T Gupta, R Sharpe, S TI Testing the chiral behavior of the hadron spectrum SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA AB We analyze the chiral behavior of the hadron spectrum obtained with quenched Wilson fermions on 170 32(3) x 64 lattices at beta = 6.0. We calculate masses of hadrons composed of both degenerate and non-degenerate quarks. We reduce the statistical errors in mass splittings by directly fitting to the ratio of correlation functions. We find significant deviations from a linear dependence on the quark mass, deviations that are consistent with the higher order terms predicted by quenched chiral perturbation theory. Including these corrections yields splittings in the baryon octet that agree with those observed experimentally. Smaller higher order terms are also present in m(p) and m(N). By contrast, the decuplet baryons are well described by a linear mass term. We find the decuplet splittings to be 30% smaller than experiment. We extrapolate our data to a --> 0 by combining with the GF11 results, and the best fit suggests that the quenched approximation is only good to 10 - 15%. C1 UNIV WASHINGTON,DEPT PHYS,SEATTLE,WA 98195. RP Bhattacharya, T (reprint author), LOS ALAMOS NATL LAB,GRP T8,MS B285,LOS ALAMOS,NM 87545, USA. RI Bhattacharya, Tanmoy/J-8956-2013 OI Bhattacharya, Tanmoy/0000-0002-1060-652X NR 4 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 549 EP 552 DI 10.1016/0920-5632(96)00119-3 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300088 ER PT J AU Arsenin, I Chen, D Christ, N Edwards, R Gara, A Hanson, S Jung, C Kahler, A Kennedy, AD Kilcup, G Luo, Y Malureanu, C Mawhinney, R Parsons, J Sexton, J Sui, C Vranas, P AF Arsenin, I Chen, D Christ, N Edwards, R Gara, A Hanson, S Jung, C Kahler, A Kennedy, AD Kilcup, G Luo, Y Malureanu, C Mawhinney, R Parsons, J Sexton, J Sui, C Vranas, P TI Status of the 0.8 teraflops supercomputer at Columbia. SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA AB The first stage in the construction of the 0.8 Teraflops Supercomputer at Columbia, a working, two node parallel computer, has been successfully completed. The next stage, a 512 node, 26 Gigaflops prototype, is in its final construction phase. A general description and current status of the hardware and software is presented. C1 COLUMBIA UNIV, NEVIS LAB, IRVINGTON, NY 10533 USA. FERMILAB NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. FLORIDA STATE UNIV, SUPERCOMP COMPUTAT RES INST, TALLAHASSEE, FL 32306 USA. OHIO STATE UNIV, DEPT PHYS, COLUMBUS, OH 43210 USA. TRINITY COLL DUBLIN, DEPT MATH, DUBLIN 2, IRELAND. RP COLUMBIA UNIV, DEPT PHYS, 538 W 120TH ST, NEW YORK, NY 10027 USA. NR 3 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 804 EP 807 DI 10.1016/0920-5632(96)00179-X PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300148 ER PT J AU Fischler, M Uchima, M AF Fischler, M Uchima, M TI Performance of the cray T3D and emerging architectures on canopy QCD applications SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA AB The Cray T3D, an MIMD system with NUMA shared memory capabilities and in principle very low communications latency, can support the Canopy framework for grid-oriented applications. CANOPY has been ported to the T3D, with the intent of making it available to 8 spectrum of users. The performance of the T3D running Canopy has been benchmarked on five QCD applications extensively run on ACPMAPS at Fermilab, requiring a variety of data access patterns. The net performance and scaling behavior reveals an efficiency relative to peak Gflops almost identical to that achieved on ACPMAPS. Detailed studies of the major factors impacting performance are presented. Generalizations applying this analysis to the newly emerging crop of commercial systems reveal where their limitations will lie. On these applications, efficiencies of above 25% are not to be expected; eliminating overheads due to Canopy will improve matters, but by less than a factor of two. RP FERMILAB NATL ACCELERATOR LAB, COMP DIV, POB 500, BATAVIA, IL 60510 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD MAR PY 1996 SU 47 BP 808 EP 811 DI 10.1016/0920-5632(96)00180-6 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300149 ER PT J AU Creutz, M AF Creutz, M TI Xtoys: Cellular automata on xwindows SO NUCLEAR PHYSICS B LA English DT Article; Proceedings Paper CT Annual International Symposium on Lattice Field Theory CY JUL 11-15, 1995 CL MELBOURNE, AUSTRALIA ID MONTE-CARLO SIMULATION AB Xtoys is a collection of xwindow programs for demonstrating simulations of various statistical models. Included are rising, for the two dimensional Ising model, xpotts, for the q-state Potts model, xautomalab, for a fairly general class of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield model of self organized criticality, and xfires, a simple forest fire simulation. The programs should compile on any machine supporting xwindows. RP Creutz, M (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,POB 5000,UPTON,NY 11973, USA. NR 9 TC 5 Z9 5 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 MAR PY 1996 SU 47 BP 846 EP 849 DI 10.1016/0920-5632(96)00191-0 PG 4 WC Physics, Particles & Fields SC Physics GA UK873 UT WOS:A1996UK87300158 ER PT J AU Dorr, MR Still, CH AF Dorr, MR Still, CH TI Concurrent source iteration in the solution of three-dimensional, multigroup discrete ordinates neutron transport equations SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID SN AB A strategy for implementing source iteration on massively parallel computers for use in solving multigroup discrete ordinates neutron transport equations on three-dimensional Cartesian grids is proposed and analyzed. Based on an analysis of the memory requirement and floating-point complexity of the formal matrix-vector multiplication effected by a single source iteration, a data decomposition and communication strategy is presented that is designed to achieve good scalability with respect to all phase-space variables, i.e., neutron position, energy, and direction. A performance model is developed to analyze the scalability properties of the algorithm and to provide computational and heuristic strategies for determining a data decomposition that minimizes wall clock execution time. Numerical results are presented to demonstrate the performance of a specific implementation of this approach on a 1024-node nCUBE/2. C1 LAWRENCE LIVERMORE NATL LAB,INERTIAL CONFINEMENT FUS CODE DEV GRP,LIVERMORE,CA 94551. RP Dorr, MR (reprint author), LAWRENCE LIVERMORE NATL LAB,CTR COMPUTAT SCI & ENGN,L-316,LIVERMORE,CA 94551, USA. NR 19 TC 6 Z9 6 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD MAR PY 1996 VL 122 IS 3 BP 287 EP 308 PG 22 WC Nuclear Science & Technology SC Nuclear Science & Technology GA UA146 UT WOS:A1996UA14600001 ER PT J AU Tzanos, CP Hunsbedt, A AF Tzanos, CP Hunsbedt, A TI Wind effects on the performance of the reactor vessel auxiliary cooling system SO NUCLEAR TECHNOLOGY LA English DT Article DE decay heat removal; passive safety systems; wind effects AB The performance of the reactor vessel auxiliary cooling system (RVACS) of a liquid-metal reactor is a function of the pressure difference between the cooling air inlet and outlet, of the air density variation along the flow path, and of the pressure loss and heat transfer characteristics of this path. The pressure difference between the air inlet and outlet as well as the RVACS inlet temperature may be affected by wind speed and direction. The objective of this work was to analyze the effects of wind on the performance of the RVACS of an advanced liquid metal reactor design based on the PRISM concept. Each stack of the reference RVACS design had two air inlets. The analysis showed that one particular wind direction had the most adverse impact on the RVACS performance. For this direction, in a two-inlet stack design, the net effect of a 27 m/s (60 mph) wind on the RVACS air flow would be a reduction of similar to 15%; while in a four-inlet design, the net effect would be nearly zero. A 15% reduction in the RVACS airflow would increase the peak cladding temperature by similar to 15 degrees C. In reality, however, the wind direction fluctuates around an average direction, and the most adverse wind effect should be <15 degrees C. The temperature at the inlet of the down wind stacks is affected by the outflow of the upwind stacks, but the effect is small. For an air temperature change of 164 degrees C along the RVACS flowpath, the maximum inlet temperature rise is similar to 5 degrees C. This would increase the peak cladding temperature by similar to 1 degrees C. C1 GE CO,NUCL ENERGY,SAN JOSE,CA 95125. RP Tzanos, CP (reprint author), ARGONNE NATL LAB,REACTOR ENGN DIV,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 10 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 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD MAR PY 1996 VL 113 IS 3 BP 249 EP 267 PG 19 WC Nuclear Science & Technology SC Nuclear Science & Technology GA TV830 UT WOS:A1996TV83000001 ER PT J AU Sofu, T Kramer, JM Cahalan, JE AF Sofu, T Kramer, JM Cahalan, JE TI SASSYS/SAS4A-FPIN2 liquid-metal reactor transient analysis code system for mechanical analysis of metallic fuel elements SO NUCLEAR TECHNOLOGY LA English DT Article DE transient analysis; liquid-metal reactors; metallic fuel AB The metal fuel version of the FPIN2 fuel element mechanics model has been incorporated into the SASSYS/SAS4A code system. In this implementation, SASSYS/SAS4A provides the fuel and cladding temperatures, and FPIN2 performs the analysis of fuel and cladding deformation. The FPIN2 results aid in the understanding of accident progression by providing the estimates of the axial expansion of fuel, time and location of cladding failure, and the condition of the fuel at the time of failure. The validation of the integrated SASSYS/SAS4A-FPIN2 model has been performed using the data from in-reactor TREAT tests for the prototypic binary and ternary fuels of the Integral Fast Reactor concept. The integrated model calculations are compared with available experimental data for the six fuel elements in these rests, and good agreement is obtained for the key parameters related to transient behavior of the metallic fast reactor fuel elements. C1 ARGONNE NATL LAB,REACTOR ENGN DIV,ARGONNE,IL 60439. RP Sofu, T (reprint author), ARGONNE NATL LAB,REACTOR ANAL DIV,ARGONNE,IL 60439, USA. NR 7 TC 2 Z9 2 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD MAR PY 1996 VL 113 IS 3 BP 268 EP 279 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA TV830 UT WOS:A1996TV83000002 ER PT J AU Oh, CH Chapman, JC AF Oh, CH Chapman, JC TI Two-phase flow instability for low-flow boiling in vertical uniformly heated thin rectangular channels SO NUCLEAR TECHNOLOGY LA English DT Article DE flow instability; heat transfer; rectangular flow channel AB Flow experiment and analysis were performed to determine flow instability condition in a single thin vertical rectangular flow channel (1.98 mm in channel gap, 50.8 mm in width, and 121.92 or 60.96 cm in heated height), which represents one of the Advanced Test Reactor's inner coolant channels between fuel plates. The maximum surface heat flux and flow rate are 159.8 kW/m(2) and 462.5 kg/s . m(2), respectively, which simulates decay heat removal from the single heated surface of the Advanced Test Reactor. The tests are conducted at atmospheric and subatmospheric pressure, simulating expected conditions during a hypothetical loss-of-coolant accident. The precursor of the flow instability [the point of net void generation and the onset of flow instability (OFI) defined by Saha and Zuber] was compared, and the OFI map (power density versus minimum mass flux at OFI) was developed in this study. RP Oh, CH (reprint author), IDAHO NATL ENGN LAB,LOCKHEED MARTIN IDAHO TECHNOL,ADV NUCL SYST TECHNOL,POB 1625,IDAHO FALLS,ID 83415, USA. NR 29 TC 3 Z9 3 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD MAR PY 1996 VL 113 IS 3 BP 327 EP 337 PG 11 WC Nuclear Science & Technology SC Nuclear Science & Technology GA TV830 UT WOS:A1996TV83000007 ER PT J AU Williams, PT Baker, AJ AF Williams, PT Baker, AJ TI Incompressible computational fluid dynamics and the continuity constraint method for the three-dimensional Navier-Stokes equations SO NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS LA English DT Review ID FINITE-ELEMENT METHOD; SEMIIMPLICIT PROJECTION METHODS; CONSISTENT MASS MATRIX; FRACTIONAL-STEP METHOD; BACKWARD-FACING STEP; VISCOUS-FLOW; RECIRCULATING-FLOWS; BOUNDARY-CONDITIONS; NATURAL-CONVECTION; NUMERICAL-SOLUTION AB Rs the field of computational fluid dynamics (CFD) continues to mature, algorithms are required to exploit the most recent advances in approximation theory, numerical mathematics, computing architectures, and hardware. Meeting this requirement is particularly challenging in incompressible fluid mechanics, where primitive-variable CFD formulations that are robust, while also accurate and efficient in three dimensions, remain an elusive goal. This monograph asserts that one key to accomplishing this goal is recognition of the dual role assumed by the pressure, i.e., a mechanism for instantaneously enforcing conservation of mass and a force in the mechanical balance law for conservation of momentum. Proving this assertion has motivated the development of a new, primitive-variable, incompressible, CFD algorithm called the continuity constraint method (CCM). The theoretical basis for the CCM consists of a finite-element spatial semidiscretization of a Galerkin weak statement, equal-order interpolation for all state variables, a theta-implicit time-integration scheme, and a quasi-Newton iterative procedure extended by a Taylor weak statement (TWS) formulation for dispersion error control. This monograph presents: (I) the formulation of the unsteady evolution of the divergence error, (2) an investigation of the role of nonsmoothness in the discretized continuity-constraint function, (3) the development of a uniformly H-1 Galerkin weak statement for the Reynolds-averaged Navier-Stokes pressure Poisson equation, and (4) a derivation of physically and numerically well-posed boundary conditions. In contrast to the general family of ''pressure-relaxation'' incompressible CFD algorithms, the CCM does not use the pressure as merely a mathematical device to constrain the velocity distribution to conserve mass. Rather, the mathematically smooth and physically motivated genuine pressure is an underlying replacement for the nonsmooth continuity-constraint function to control inherent dispersive-error mechanisms. The genuine pressure is calculated by the diagnostic pressure Poisson equation, evaluated using the verified solenoidal velocity field. This new separation of tasks also produces a genuinely clear view of the totally distinct boundary conditions required for the continuity-constraint function and genuine pressure. C1 UNIV TENNESSEE, DEPT ENGN SCI & MECH, KNOXVILLE, TN 37996 USA. RP OAK RIDGE NATL LAB, COMPUTAT PHYS & ENGN DIV, POB 2008, BLDG 6011, MS-6415, OAK RIDGE, TN 37831 USA. NR 184 TC 29 Z9 30 U1 1 U2 11 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 1040-7790 EI 1521-0626 J9 NUMER HEAT TR B-FUND JI Numer Heat Tranf. B-Fundam. PD MAR PY 1996 VL 29 IS 2 BP 137 EP 273 DI 10.1080/10407799608914980 PG 137 WC Thermodynamics; Mechanics SC Thermodynamics; Mechanics GA UA880 UT WOS:A1996UA88000002 ER PT J AU Loehle, C AF Loehle, C TI Optimal defensive investments in plants SO OIKOS LA English DT Article ID RESOURCE AVAILABILITY HYPOTHESIS; GROWTH-RATE; ANTIHERBIVORE DEFENSE; HERBIVORY; SHRUBS AB Basey and Jenkins (1993; Oikos 68: 323-328) analyzed the growth-defense tradeoff model of Coley et al. (1985; Science 230: 895-899) and concluded that plants with high inherent growth rates should be virtually without immobile, nontoxic (quantitative) defenses. Plants with low inherent growth rates should have the maximum possible level of these defenses, with no intermediate types. Here, two types of evidence are presented from trees in support of these predictions. For North American broadleaf trees, volumetric heat content of wood is significantly different between discrete groups of short-lived, fast-growing versus long-lived, slow-growing species. For North American pines, two discrete groups are also found: a short-lived group with a high investment in leaves versus other tissue and a long-lived group with a low investment in leaves. Life span is argued to be a useful indicator of the net combined benefit of multiple quantitative defenses and is likely the life history parameter in trees that drives the selection for high or low defenses. RP Loehle, C (reprint author), ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439, USA. NR 14 TC 17 Z9 17 U1 2 U2 14 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0030-1299 J9 OIKOS JI Oikos PD MAR PY 1996 VL 75 IS 2 BP 299 EP 302 DI 10.2307/3546253 PG 4 WC Ecology SC Environmental Sciences & Ecology GA UL869 UT WOS:A1996UL86900017 ER PT J AU Rao, NSV Iyengar, SS AF Rao, NSV Iyengar, SS TI Distributed decision fusion under unknown distributions SO OPTICAL ENGINEERING LA English DT Article DE sensor fusion; distributed decision fusion; empirical estimation; nearest-neighbor rule; neural networks; Lipschitz functions ID COMPLEXITY AB The problem of distributed decision fusion is studied in the case when the probability distributions of the individual detectors are not available. The detector system is available so that a training sample can be generated by sensing objects with known parameters or classification. Earlier solutions to this problem required some knowledge of the error distributions of the detectors, for example, either in a parametric form or in a closed analytical form. Here we present three methods that, given a sufficiently large training sample, yield an approximation to the optimal fusion rule with an arbitrary level of confidence. These methods are based on (i) empirical estimation, (ii) approximate decision rule, and (iii) nearest-neighbor rule, We show that a nearest-neighbor rule provides a computationally viable solution, which approximates a neural network-based one while ensuring fast computation. (C) 1996 Society of Photo-Optical Instrumentation Engineers. C1 LOUISIANA STATE UNIV,DEPT COMP SCI,BATON ROUGE,LA 70803. RP Rao, NSV (reprint author), OAK RIDGE NATL LAB,CTR ENGN SYST ADV RES,OAK RIDGE,TN 37831, USA. NR 24 TC 13 Z9 13 U1 0 U2 1 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1996 VL 35 IS 3 BP 617 EP 624 DI 10.1117/1.600635 PG 8 WC Optics SC Optics GA UA470 UT WOS:A1996UA47000004 ER PT J AU Golovlyov, VV Garrett, WR Chen, CH AF Golovlyov, VV Garrett, WR Chen, CH TI Dynamics of optical damage of thin aluminum film irradiated by picosecond laser pulses SO OPTICAL ENGINEERING LA English DT Article DE optical damage; thin aluminum film; picosecond laser pulses; hydrodynamic expansion ID ABSORPTION; PLASMAS AB Time resolved reflectivity measurements of thin aluminum films undergoing damage by picosecond laser pulses are described. Experimental results are compared with results from reflectance calculations using the model of hydrodynamic expansion of a metal layer heated by a short laser pulse. Both experimental and theoretical results confirm that thin metal films are useful as damageable optical elements in an optical power limiting device. (C) 1996 Society of Photo-Optical Instrumentation Engineers. RP Golovlyov, VV (reprint author), OAK RIDGE NATL LAB,BLDG 5500,MS-6378,POB 2008,OAK RIDGE,TN 37831, USA. NR 13 TC 0 Z9 0 U1 0 U2 2 PU SOC PHOTO-OPT INSTRUM ENG PI BELLINGHAM PA PO BOX 10, BELLINGHAM, WA 98227-0010 SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 1996 VL 35 IS 3 BP 895 EP 899 DI 10.1117/1.600665 PG 5 WC Optics SC Optics GA UA470 UT WOS:A1996UA47000037 ER PT J AU Nilsen, J Li, YL Lu, PX Moreno, JC Fill, EE AF Nilsen, J Li, YL Lu, PX Moreno, JC Fill, EE TI Relative merits of using curved targets and the prepulse technique to enhance the output of the neon-like germanium X-ray laser SO OPTICS COMMUNICATIONS LA English DT Article AB We present a series of experiments using germanium slab targets with either flat or curved surfaces which are illuminated by a low intensity prepulse before the main optical drive pulse of the 1.315 mu m Asterix iodine laser. By varying the radius of curvature of the target surface and the size of the prepulse we show the relative merits of these two effects on improving the output of the neon-like germanium 3p(1)S(0) --> 3s(1)P(1) lasing transition at 196 Angstrom. While the curved targets do improve the laser output at 196 Angstrom, the use of the prepulse technique is shown to be much more important in increasing the laser output. We also discuss the relative effect on the other two important germanium laser lines at 232 and 236 Angstrom. C1 MAX PLANCK INST QUANTUM OPT,D-85740 GARCHING,GERMANY. ACAD SINICA,SHANGHAI INST OPT & FINE MECH,SHANGHAI 201800,PEOPLES R CHINA. RP Nilsen, J (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 19 TC 14 Z9 14 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD MAR 1 PY 1996 VL 124 IS 3-4 BP 287 EP 291 DI 10.1016/0030-4018(95)00658-3 PG 5 WC Optics SC Optics GA UE671 UT WOS:A1996UE67100017 ER PT J AU Boreman, GD Dogariu, A Christodoulou, C Kotter, D AF Boreman, GD Dogariu, A Christodoulou, C Kotter, D TI Dipole-on-dielectric model for infrared lithographic spiral antennas SO OPTICS LETTERS LA English DT Article AB We present a dipole-on-dielectric model for lithographic antennas used for bolometer coupling in the infrared. The predicted antenna patterns show good agreement with measurements of Au-on-Si spiral antennas at 9.5-mu m wavelength. Angle- and polarization-resolved measurements are proposed, which will further probe the behavior of these antenna structures and facilitate refinement of the analytical models. (C) 1996 Optical Society of America C1 UNIV CENT FLORIDA,DEPT ELECT ENGN,ORLANDO,FL 32816. UNIV CENT FLORIDA,DEPT ELECT ENGN,ORLANDO,FL 32816. LOCKHEED MARTIN CORP,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. RP Boreman, GD (reprint author), UNIV CENT FLORIDA,CTR RES & EDUC OPT & LASERS,ORLANDO,FL 32816, USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAR 1 PY 1996 VL 21 IS 5 BP 309 EP 311 DI 10.1364/OL.21.000309 PG 3 WC Optics SC Optics GA TX560 UT WOS:A1996TX56000001 PM 19865388 ER PT J AU Rashid, H Smith, DA Bao, Z Chakravarthy, RS Pathan, MA Imam, N Kissa, K Kallman, J AF Rashid, H Smith, DA Bao, Z Chakravarthy, RS Pathan, MA Imam, N Kissa, K Kallman, J TI Use of radio-frequency-pulse surface acoustic wave profilometry for passband engineering of acousto-optic tunable filters SO OPTICS LETTERS LA English DT Article AB One can determine the acoustic profile of an acousto-optic tunable filter (AOTF) either by measuring the intensity of a laser diffracted off the surface of an AOTF by the surface acoustic wave (SAW) or by measuring the optical output power of an AOTF as a short burst of rf energy is launched down the device. This rf-burst technique (also called pulse probing) is compared with the established optical diffraction SAW profilometry technique. We demonstrate the usefulness of rf-burst profilometry to measure the acousto-optic coupling as a function of position along an AOTF interaction region. Such a probe can be used to make adjustments to the acousto-optic coupling in real time to achieve passband shape modification in complex AOTF structures. (C) 1996 Optical Society of America C1 UNIPHASE TELECOMMUN PROD,BLOOMFIELD,CT 06002. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Rashid, H (reprint author), CASE WESTERN RESERVE UNIV,DEPT ELECT ENGN & APPL PHYS,10900 EUCLID AVE,CLEVELAND,OH 44106, USA. NR 6 TC 3 Z9 3 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAR 1 PY 1996 VL 21 IS 5 BP 342 EP 344 DI 10.1364/OL.21.000342 PG 3 WC Optics SC Optics GA TX560 UT WOS:A1996TX56000012 PM 19865399 ER PT J AU Soref, RA Atzman, Z Shaapur, F Robinson, M Westhoff, R AF Soref, RA Atzman, Z Shaapur, F Robinson, M Westhoff, R TI Infrared waveguiding in Si(1-x-y)GexCy upon silicon SO OPTICS LETTERS LA English DT Article AB Polarization-independent waveguiding at 1.32 and 1.54 mu m was observed in single-crystal S1-x-yGexCy grown nearly lattice matched upon Si(100) by chemical vapor deposition. Losses were <5 dB/cm at 1.54 mu m. Experiments indicate that the band gap of three SiGeC alloy waveguides was in the 0.93-0.99-eV range, in agreement with theory. (C) 1996 Optical Society of America C1 ARIZONA STATE UNIV,DEPT CHEM BIO & MAT ENGN,TEMPE,AZ 85287. LAWRENCE SEMICOND RES LAB INC,TEMPE,AZ 85282. RP Soref, RA (reprint author), USAF,ROME LAB,RL EROC,HANSCOM AFB,BEDFORD,MA 01731, USA. NR 7 TC 16 Z9 16 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAR 1 PY 1996 VL 21 IS 5 BP 345 EP 347 DI 10.1364/OL.21.000345 PG 3 WC Optics SC Optics GA TX560 UT WOS:A1996TX56000013 PM 19865400 ER PT J AU Tozer, TN Bois, FY Hauck, WW Chen, ML Williams, RL AF Tozer, TN Bois, FY Hauck, WW Chen, ML Williams, RL TI Absorption rate vs exposure: Which is more useful for bioequivalence testing? SO PHARMACEUTICAL RESEARCH LA English DT Article DE absorption rate; bioequivalence; C-max/AUC(lqc); C-max; AUC; exposure AB Purpose. The goals were to evaluate the usefulness of C-max/AUC(1qc), ratio of the maximum plasma drug concentration to the area under the plasma concentration-time curve to the time of the last quantifiable concentration, in bioequivalence testing and to explore the use of exposure as a replacement for the concepts of rate and extent of drug absorption. Methods. The bioequivalence of products differing in both rate (ka) and extent (F) of absorption was assessed under conditions similar to those encountered in a typical trial. A one-compartment model drug with first-order absorption (rate constant = ka) and elimination was used. Variability was introduced in all model parameters using Monte Carlo techniques. The results were expressed in terms of the probability of declaring bioequivalence in a cross-over trial with 24 subjects using C-max/AUC(1qc), AUC(1qc), and C-max as bioequivalence measures. Results. The outcome of a bioequivalence trial was shown to depend on the measure. C-max/AUC(1qc) reflected changes in ka, but not in F. AUC(1qc) showed dependence on F, but virtually no dependence on ka. For C-max a 3- to 4-fold increase in ka and a concomittant 20% decrease in F, as well as corresponding changes in the opposite directions, resulted in bioequivalent outcomes. Conclusions. It was concluded that use of Cmax/AUC(1qc) should be discouraged and that defining bioequivalence in terms of rate and extent of absorption has major problems. The goal of bioequivalence trials should be to assure that the shape of the concentration-time curve of the test product is sufficiently similar to that of the reference product. To this end, the use of ''exposure'' rather than ''rate and extent of absorption'' concepts is encouraged. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,INDOOR ENVIRONM PROGRAM,BERKELEY,CA 94720. THOMAS JEFFERSON UNIV,BIOSTAT SECT,DIV CLIN PHARMACOL,PHILADELPHIA,PA 19107. US FDA,CTR DRUG EVALUAT & RES,ROCKVILLE,MD 20857. RP Tozer, TN (reprint author), UNIV CALIF SAN FRANCISCO,SCH PHARM,DEPT PHARM,SAN FRANCISCO,CA 94143, USA. RI Bois, Frederic/E-9241-2012 OI Bois, Frederic/0000-0002-4154-0391 NR 15 TC 47 Z9 47 U1 0 U2 1 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0724-8741 J9 PHARMACEUT RES JI Pharm. Res. PD MAR PY 1996 VL 13 IS 3 BP 453 EP 456 DI 10.1023/A:1016061013606 PG 4 WC Chemistry, Multidisciplinary; Pharmacology & Pharmacy SC Chemistry; Pharmacology & Pharmacy GA UB418 UT WOS:A1996UB41800019 PM 8692741 ER PT J AU Wang, J Wolf, D Phillpot, SR Gleiter, H AF Wang, J Wolf, D Phillpot, SR Gleiter, H TI Computer simulation of the structure and thermo-elastic properties of a model nanocrystalline material SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID SIZED CRYSTALLINE MATERIALS; ENHANCED SPECIFIC-HEAT; GRAIN-BOUNDARIES; FCC METALS; ENERGY; SPECTROSCOPY; PALLADIUM AB A model of a space-filling, monodisperse nanocrystalline material, consisting of identically shaped rhombohedral grains connected by identical grain boundaries, is presented. In the limit of infinite grain size, the model reproduces the corresponding bicrystalline grain boundary; variation of the grain size therefore permits the role of the microstructural constraints on the atomic structure and properties of the grain boundaries in the polycrystal to be elucidated. Lattice-statics simulations performed on this model reveal that the relaxed zero-temperature structures of the grain boundaries differ only slightly from those of unconstrained boundaries. The vibrational densities of state of the nanocrystalline material and of the related glass, determined from lattice-dynamics simulations, exhibit low- and high-frequency modes not seen in the perfect crystal. The low-frequency modes give rise to a low-temperature peak in the excess specific heat in both types of metastable microstructures. Free-energy simulations suggest that a phase transition from the nanocrystalline state to the glass should occur below a critical grain size. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. FORSCHUNGSZENTRUM KARLSRUHE,D-76921 KARLSRUHE,GERMANY. RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 47 TC 66 Z9 73 U1 3 U2 11 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD MAR PY 1996 VL 73 IS 3 BP 517 EP 555 PG 39 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA UE042 UT WOS:A1996UE04200001 ER PT J AU McGibbon, MM Browning, ND McGibbon, AJ Pennycook, SJ AF McGibbon, MM Browning, ND McGibbon, AJ Pennycook, SJ TI The atomic structure of asymmetric [001] tilt boundaries in SrTiO3 SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID RESOLUTION ELECTRON-MICROSCOPY; ENERGY-LOSS SPECTROSCOPY; TRANSITION-METAL OXIDES; GRAIN-BOUNDARIES; CRYSTAL-STRUCTURE; PARAMETERS AB The atomic structures of 25 degrees and 45 degrees asymmetric [001] tilt boundaries in SrTiO3 have been determined experimentally using the unique combination of high-resolution Z-contrast imaging and simultaneous electron-energy-loss spectroscopy in the scanning transmission electron microscope. These complementary techniques permit the direct location of the cation columns at the boundary to an accuracy of 0.2 Angstrom and the coordination of the O atoms to be investigated with atomic resolution. Using bond-valence sum calculations, the structural and electronic results were combined to produce models for the grain-boundary structures. These calculations highlighted the presence of half-occupied columns at both grain boundaries as an important feature for reducing the grain-boundary energy associated with these ionic materials. In addition, the grain-boundary structure units identified in the experimental images were used to predict structures for other misorientations by the application of the principles of continuity of grain-boundary structure. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. OI Browning, Nigel/0000-0003-0491-251X NR 32 TC 53 Z9 53 U1 0 U2 12 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD MAR PY 1996 VL 73 IS 3 BP 625 EP 641 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA UE042 UT WOS:A1996UE04200006 ER PT J AU SanchezCastro, C AF SanchezCastro, C TI Temperature and field dependence of the thermodynamic and transport properties of Ce3Bi4Pt3 SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID HYBRIDIZATION GAP AB We have calculated the temperature and held dependence of various thermodynamic and transport properties for the insulating phase of the Anderson lattice Hamiltonian using a slave boson approach. The conduction band was assumed to be a tight binding cubic s-band. The transport properties were calculated assuming impurity scattering and using a relaxation time approximation. Many-body effects due to the on-site f electron Coulomb repulsion are shown to be crucial in describing the mixed valence nature and the different energy scales observed in Ce3Bi4Pt3. The calculated electrical conductivity and thermopower agree with experiment but the Hall constant does not. We present predictions for the thermal conductivity and the thermoelectric figure of merit as a function of temperature. We predict that under a magnetic field H-c similar or equal to 90 T the system undergoes a transition from an insulator to a metal with a finite magnetic susceptibility and specific heat (sic). C1 LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. NR 25 TC 4 Z9 4 U1 1 U2 5 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0141-8637 J9 PHILOS MAG B JI Philos. Mag. B-Phys. Condens. Matter Stat. Mech. Electron. Opt. Magn. Prop. PD MAR PY 1996 VL 73 IS 3 BP 525 EP 542 DI 10.1080/13642819608239133 PG 18 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA UE043 UT WOS:A1996UE04300009 ER PT J AU Chayes, L Emery, VJ Kivelson, SA Nussinov, Z Tarjus, G AF Chayes, L Emery, VJ Kivelson, SA Nussinov, Z Tarjus, G TI Avoided critical behavior in a uniformly frustrated system SO PHYSICA A LA English DT Article DE avoided critical point; uniform frustration; spherical spin miodel ID PHASE-TRANSITIONS; RANDOM FIELDS; MODEL; DIMENSIONALITY; SEPARATION AB We study the effects of weak long-ranged antiferromagnetic interactions of strength a on a spin model with predominant short-ranged ferromagnetic interactions, In three dimensions, this model exhibits an avoided critical point in the sense that the critical temperature T-c(Q = 0) is strictly greater than lim(Q-->0) T-c(Q). The behavior of this system at temperatures less than T-c(Q = 0) is controlled by the proximity to the avoided critical point. We also quantize the model in a novel way to study the interplay between charge-density wave and superconducting order. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. UNIV CALIF LOS ANGELES,DEPT PHYS,LOS ANGELES,CA 90095. UNIV PARIS 06,PHYS THEOR LIQUIDES LAB,F-75252 PARIS 05,FRANCE. RP Chayes, L (reprint author), UNIV CALIF LOS ANGELES,DEPT MATH,LOS ANGELES,CA 90095, USA. NR 21 TC 75 Z9 76 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAR 1 PY 1996 VL 225 IS 1 BP 129 EP 153 DI 10.1016/0378-4371(95)00374-6 PG 25 WC Physics, Multidisciplinary SC Physics GA TY822 UT WOS:A1996TY82200007 ER PT J AU Park, M Kramer, MJ Dennis, KW McCallum, RW AF Park, M Kramer, MJ Dennis, KW McCallum, RW TI Phase equilibria in the Pr-Ba-Cu-O system under varied oxygen partial pressures SO PHYSICA C LA English DT Article ID PHYSICAL-PROPERTIES; NEUTRON-DIFFRACTION; LIQUIDUS RELATIONS; RARE-EARTH; SUPERCONDUCTIVITY; PRBA2CU3O7-Y; SUBSTITUTION; SUPPRESSION; OXIDES; ND AB Phase equilibria in the Pr-Ba-Cu-O system under varied oxygen partial pressure (pO(2)) is investigated. Stoichiometric PrBa2Cu3O7-delta (Pr123) does not exist for pO(2) < 1 bar O-2. Instead, nominal Pr123 is a mixture of Pr1+xBa2-xCu3O7+delta solid-solution (Pr123(55)) and BaCuO2. When nominal Pr123 is processed at 900 degrees C in 1 bar O-2, the lower limit for x is 0.04. As the pO(2) is lowered, the occupancy of the Pr ions on the Pa sites is decreased. The minimum lower limit of x is similar to 0.01 at 900 degrees C using a pO(2) of 0.001 atm. Further reducing the pO(2) causes the BaCu2O2 and PrBaO3 phases to form. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. NR 30 TC 38 Z9 38 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAR 1 PY 1996 VL 259 IS 1-2 BP 43 EP 53 DI 10.1016/0921-4534(96)00006-8 PG 11 WC Physics, Applied SC Physics GA UC728 UT WOS:A1996UC72800005 ER PT J AU Tzeng, Y Kuo, TTS Lee, TSH AF Tzeng, Y Kuo, TTS Lee, TSH TI The effect of the Delta excitation on the nucleon-nucleon effective interactions in the nuclear shell-model SO PHYSICA SCRIPTA LA English DT Article ID 3-NUCLEON FORCE; NN SCATTERING; MESON THEORY; PI; DIAGRAMS; FREEDOM; MATTER; SYSTEM AB The effect of Delta excitation on the shell-model effective NN interactions is investigated by evaluating the Delta-particle nucleon-hole core polarization diagrams within the folded-diagram formulation. The calculation has been performed using the NN<->N Delta transition G-matrix generated from a coupled-channel pi NN model which is constrained by the NN data up to 1 GeV and is based on a Delta-subtracted Paris potential. Satisfactory convergence of the calculation is reached by including the Delta excitations up to 20 oscillator shells. The Delta-particle nucleon-hole core-polarization diagrams are found to be small for the sd-shell valence nucleons. C1 SUNY STONY BROOK, DEPT PHYS, STONY BROOK, NY 11794 USA. ARGONNE NATL LAB, DIV PHYS, ARGONNE, IL 60439 USA. RP Tzeng, Y (reprint author), ACAD SINICA, INST PHYS, TAIPEI 11529, TAIWAN. NR 30 TC 6 Z9 8 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0031-8949 EI 1402-4896 J9 PHYS SCRIPTA JI Phys. Scr. PD MAR PY 1996 VL 53 IS 3 BP 300 EP 305 DI 10.1088/0031-8949/53/3/004 PG 6 WC Physics, Multidisciplinary SC Physics GA TZ657 UT WOS:A1996TZ65700004 ER PT J AU Phillips, JE Birkmire, RW McCandless, BE Meyers, PV Shafarman, WN AF Phillips, JE Birkmire, RW McCandless, BE Meyers, PV Shafarman, WN TI Polycrystalline heterojunction solar cells: A device perspective SO PHYSICA STATUS SOLIDI B-BASIC RESEARCH LA English DT Article AB Analysis of high efficiency, thin film, small grain, polycrystalline, heterojunction CdTe and CuInSe2 based solar cells can help explain the high quantum efficiencies and the resulting short circuit current (J(SC)) as well as the forward diode current that controls the open circuit voltage (V-OC). This analysis shows that minority carrier recombination at the metallurgical interface and at grain boundaries is greatly reduced by the propel ''doping'' of the window and absorber layers thereby increasing J(SC). Additional analysis and measurements show that tile V-OC in present stale of tie art solar cells is controlled by tile magnitude of the forward diode current which appears to be caused by recombination in the space charge region of the absorber layer. This also shows that any quantitative modeling of these devices which relates the device performance to tile bulk electronic proper ties of the material should consider the additional geometric dimension introduced by the polycrystallinity because of grain boundary effects. RP Phillips, JE (reprint author), UNIV DELAWARE,UNIV CTR EXCELLENCE PHOTOVOLTA RES & EDUC,US DEPT ENERGY,INST ENERGY CONVERS,NEWARK,DE 19716, USA. NR 22 TC 22 Z9 22 U1 0 U2 5 PU AKADEMIE VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0370-1972 J9 PHYS STATUS SOLIDI B JI Phys. Status Solidi B-Basic Res. PD MAR PY 1996 VL 194 IS 1 BP 31 EP 39 DI 10.1002/pssb.2221940105 PG 9 WC Physics, Condensed Matter SC Physics GA UB683 UT WOS:A1996UB68300004 ER PT J AU Morehead, JJ AF Morehead, JJ TI Semiclassical integrable matrix elements SO PHYSICAL REVIEW A LA English DT Article ID APPROXIMATION; STATES AB A semiclassical expression for matrix elements of an arbitrary operator with respect to the eigenstates of an integrable Hamiltonian is derived. This is essentially the Heisenberg correspondence principle, and it is shown via the Weyl correspondence that the approximation is valid through the lowest two orders in h. The result is used to prove that an asymptotic form of the Clebsch-Gordan coefficients for two large and one small angular momenta is valid through two orders. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Morehead, JJ (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 15 TC 21 Z9 23 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1996 VL 53 IS 3 BP 1285 EP 1294 DI 10.1103/PhysRevA.53.1285 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700014 ER PT J AU Johnson, WR Cheng, KT AF Johnson, WR Cheng, KT TI Relativistic configuration-interaction calculation of the polarizabilities of heliumlike ions SO PHYSICAL REVIEW A LA English DT Article ID HEAVY ATOMS AB Polarizabilities of ions of the helium isoelectronic sequence with nuclear charges in the range 2 less than or equal to Z less than or equal to 30 are evaluated starting from the relativistic no-pair Hamiltonian and including both the Coulomb and Breit interactions. The ground state and perturbed wave functions are expanded in two-electron basis functions constructed from B splines. For each ion, the ground-state wave function is determined by a configuration interaction calculation; the perturbed wave function is then found by solving an inhomogeneous algebraic equation. Nonrelativistic calculations are carried out in parallel with the relativistic calculations, permitting relativistic corrections to be isolated. The present nonrelativistic calculations are found to be in good agreement with other precise calculations. For the experimentally interesting case of heliumlike lithium, we obtain the value Delta alpha(Rel) = - (4.50 +/- 0.05) x 10(-5) a.u. for the relativistic correction to the ground-state polarizability. C1 UNIV CALIF,LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Johnson, WR (reprint author), UNIV NOTRE DAME,DEPT PHYS,NOTRE DAME,IN 46556, USA. NR 12 TC 34 Z9 34 U1 0 U2 4 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 MAR PY 1996 VL 53 IS 3 BP 1375 EP 1378 DI 10.1103/PhysRevA.53.1375 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700023 ER PT J AU Wells, JC Oberacker, VE Strayer, MR Umar, AS AF Wells, JC Oberacker, VE Strayer, MR Umar, AS TI Convergence of a lattice calculation for bound-free muon-pair production in peripheral relativistic heavy-ion collisions SO PHYSICAL REVIEW A LA English DT Article ID ELECTRON-CAPTURE; FERMIONS; FIELDS; ENERGIES; TIME AB We have developed a nonperturbative treatment of bound-free lepton-pair production caused by the strong and sharply pulsed electromagnetic fields generated by heavy ions in peripheral, relativistic collisions based on the solution of the time-dependent Dirac equation using lattice techniques. In this paper, we discuss refinements and extensions of our numerical methods for this problem and demonstrate convergent calculations, with respect to the parameters of the lattice, for bound-free muon-pair production in collisions near grazing incidence of U-238(92+)+U-238(92+) and beam kinetic energies of 30 GeV per nucleon in the fixed-target frame. C1 OAK RIDGE NATL LAB,DIV PHYS,CTR COMPUTAT INTENS PHYS,OAK RIDGE,TN 37831. VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235. RP Wells, JC (reprint author), HARVARD SMITHSONIAN CTR ASTROPHYS,60 GARDEN ST,CAMBRIDGE,MA 02138, USA. RI Umar, Ahmet/J-4125-2013; Wells, Jack/D-3675-2016 OI Umar, Ahmet/0000-0002-9267-5253; Wells, Jack/0000-0002-5083-3030 NR 44 TC 11 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1996 VL 53 IS 3 BP 1498 EP 1504 DI 10.1103/PhysRevA.53.1498 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700038 ER PT J AU Pindzola, MS Schultz, DR AF Pindzola, MS Schultz, DR TI Time-dependent dose-coupling method for electron-impact ionization of hydrogen SO PHYSICAL REVIEW A LA English DT Article ID CROSS-SECTIONS; INTERMEDIATE ENERGIES; SCHRODINGER-EQUATION; SCATTERING; MODEL; ATOMS AB Electron-impact ionization of atomic hydrogen is studied by direct solution of a set of time-dependent close-coupled partial differential equations. The close-coupled equations describe the propagation of a time-evolving wave packet on a two-dimensional radial lattice. Following the collision, the wave packet is projected onto stationary states of the target to obtain probabilities for elastic and inelastic scattering processes. Ionization cross sections are calculated for various LS partial waves and compared with previous theoretical methods. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RP Pindzola, MS (reprint author), AUBURN UNIV,DEPT PHYS,AUBURN,AL 36849, USA. NR 36 TC 78 Z9 78 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1996 VL 53 IS 3 BP 1525 EP 1536 DI 10.1103/PhysRevA.53.1525 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700041 ER PT J AU Momberger, K Belkacem, A Sorensen, AH AF Momberger, K Belkacem, A Sorensen, AH TI Numerical treatment of the time-dependent Dirac equation in momentum space for atomic processes in relativistic heavy-ion collisions SO PHYSICAL REVIEW A LA English DT Article ID POSITRON PAIR PRODUCTION; K-SHELL IONIZATION; FINITE-DIFFERENCE METHOD; ELECTRON-CAPTURE; NONPERTURBATIVE CHARACTER; MULTIPLE IONIZATION; CHARGE-TRANSFER; CROSS-SECTIONS; URANIUM IONS; EXCITATION AB A numerical method for the solution of the time-dependent Dirac equation to describe atomic processes in relativistic heavy-ion collisions is presented. Different from previous approaches found in the literature, we are working entirely in momentum space to propagate the electron wave function in time. Due to the localization of the electron in momentum space the wave function can be confined to a finite discretization volume without the stringent violation of the boundary conditions which is encountered in configuration-space methods. From the final state, we can extract probabilities on inner-shell ionization, excitation, electron transfer, and bound free pair production. Results are presented in the energy range from 0.24 to 10 GeV/nucleon. At 0.24 GeV/nucleon we demonstrate that our formalism incorporates both the ionization and the transfer channel, which are equally important at this energy. At higher energies from 0.93 to 10 GeV/nucleon we focus on ionization and bound-free pair production. We find that the enhancement of bound-free pair production as compared to perturbation theory is much smaller than reported previously by others. C1 AARHUS UNIV,INST PHYS & ASTRON,DK-8000 AARHUS C,DENMARK. RP Momberger, K (reprint author), LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 77 TC 50 Z9 50 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 MAR PY 1996 VL 53 IS 3 BP 1605 EP 1622 DI 10.1103/PhysRevA.53.1605 PG 18 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700050 ER PT J AU Drexler, CG Dubois, RD AF Drexler, CG Dubois, RD TI Energy- and angle-differential yields of electron emission from thin carbon foils after fast proton impact SO PHYSICAL REVIEW A LA English DT Article ID SOLID-SURFACES; EXIT SURFACES; BOMBARDMENT; ENTRANCE; H+ AB Proton-induced electron emission from sputter-cleaned thin carbon targets was investigated under ultrahigh vacuum conditions using time-of-flight energy analysis. These data emphasized the low-energy portion, e.g., E(e) < 20 eV, of the spectrum. Energy distributions of the emitted electrons were measured as a function of the emission angle, impact energy, and foil thickness. C1 GESELL STRAHLEN & UMWELTFORSCH MBH, FORSCHUNGSZENTRUM UMWELT & GESUNDHEIT NEUHERBERG, D-85758 OBERSCHLEISSHEIM, GERMANY. PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Drexler, CG (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 25 TC 15 Z9 15 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 MAR PY 1996 VL 53 IS 3 BP 1630 EP 1637 DI 10.1103/PhysRevA.53.1630 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700052 ER PT J AU LaGattuta, KJ AF LaGattuta, KJ TI Interaction of half-cycle radiation pulse with polarized states of atomic hydrogen SO PHYSICAL REVIEW A LA English DT Article AB We describe the results of our solutions of the time-dependent Schrodinger equation for polarized states of atomic hydrogen exposed to a short pulse of intense, long-wavelength, continuum radiation. The duration of the pi-polarized unipolar pulse is of the order of the Kepler period of the state being irradiated, and the pulse is sufficiently intense to ionize a significant fraction of the initial state. Markedly different behavior is observed for the maximally ''redshifted'' versus the maximally ''blueshifted'' initial state, depending upon whether the pulse duration is less than or greater than the underlying Kepler period. RP LaGattuta, KJ (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 8 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1996 VL 53 IS 3 BP 1762 EP 1766 DI 10.1103/PhysRevA.53.1762 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA TY087 UT WOS:A1996TY08700066 ER PT J AU Fullerton, EE Bader, SD AF Fullerton, EE Bader, SD TI Temperature-dependent biquadratic coupling in antiferromagnetically coupled Fe/FeSi multilayers SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC MULTILAYERS; EXCHANGE; SUPERLATTICES; FERROMAGNETS; SPACER AB Fe/FeSi multilayers are known to exhibit a strong antiferromagnetic interlayer coupling peak centered at a nominal FeSi spacer thickness of similar to 15+/-2 Angstrom at room temperature, and to develop remanence in the magnetic hysteresis loop upon cooling to similar to 100 K. An analysis of the hysteresis loops is found to require the inclusion of a temperature-dependent biquadratic (90 degrees coupling) in addition to the bilinear coupling term in the energetics. The temperature dependence of the Fe/FeSi multilayer coupling can then be understood in terms that are applicable to conventional metallic multilayer systems such as Fe/Cr. RP Fullerton, EE (reprint author), ARGONNE NATL LAB,DIV SCI MAT,ARGONNE,IL 60439, USA. RI Bader, Samuel/A-2995-2013; Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 36 TC 81 Z9 81 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5112 EP 5115 DI 10.1103/PhysRevB.53.5112 PG 4 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100020 ER PT J AU Schultz, AJ Jorgensen, JD Peng, JL Greene, RL AF Schultz, AJ Jorgensen, JD Peng, JL Greene, RL TI Single-crystal neutron-diffraction structures of reduced and oxygenated Nd2-xCexCuOy SO PHYSICAL REVIEW B LA English DT Article ID GROWTH; ND1.85CE0.15CUO4-DELTA AB The structures of single crystals of oxygenated and reduced (T-c=24 K) Nd1.85Ce0.15CuOy (y approximate to 4) were examined by neutron diffraction. Although refinements of various models including interstitial oxygen atoms was inconclusive, Fourier maps of the oxygenated crystal exhibit peaks at the apical O(3) oxygen site. This peak is almost entirely absent in the superconducting reduced crystal. These results are consistent with results from a previous study of oxygenated and reduced Nd2CuOy. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCONDUCT,ARGONNE,IL 60439. UNIV MARYLAND,DEPT PHYS & ASTRON,CTR SUPERCONDUCT RES,COLLEGE PK,MD 20742. RP Schultz, AJ (reprint author), ARGONNE NATL LAB,DIV SCI MAT,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 15 TC 82 Z9 83 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5157 EP 5159 DI 10.1103/PhysRevB.53.5157 PG 3 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100032 ER PT J AU Samara, GA Hansen, LV Morosin, B Schirber, JE AF Samara, GA Hansen, LV Morosin, B Schirber, JE TI Effects of pressure and ambient species on orientational ordering in solid C-7O SO PHYSICAL REVIEW B LA English DT Article ID C60 AB The effects of hydrostatic pressure on the orientational ordering phase transitions in solid C-70 were investigated by differential thermal analysis (DTA) using helium and nitrogen gases as pressure-transmitting media. The different observed responses in these media for the different transitions and for different samples, as well as some irreversible pressure/temperature cycling effects, have provided much insight into the ordering processes and into the influence of interstitial lattice impurities on these processes. Compression of the lattice strongly hinders the rotational motion of the C-70 molecules, especially their high-temperature tumbling motions, and results in stabilization of the ordered low-temperature phases. This feature reflects the weak van der Waals intermolecular bonding and the high sensitivity of the rotational barriers to intermolecular separation. In microscopic terms, the results can be understood in terms of pressure-induced enhancement of the nesting of electron-rich and electron-poor regions of the C-70 molecular cages. Observations of the evolution of DTA spectra during compression and as a function of time after release of pressure revealed a variety of nearly degenerate (in energy) configurations which are believed to be due to either hindered rotations of the molecules by interstitial impurities or to different stacking sequences of the monomolecular C-70 layers. The results are compared with earlier findings on solid C-60. RP Samara, GA (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 15 TC 5 Z9 5 U1 2 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5211 EP 5216 DI 10.1103/PhysRevB.53.5211 PG 6 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100041 ER PT J AU Kenkre, VM Raghavan, S Bishop, AR Salkola, MI AF Kenkre, VM Raghavan, S Bishop, AR Salkola, MI TI Memory-function approach to interacting quasiparticle boson systems SO PHYSICAL REVIEW B LA English DT Article ID NONLINEAR SCHRODINGER-EQUATION; MOLECULAR-CRYSTALS; DAVYDOV SOLITONS; SEMICLASSICAL APPROXIMATION; QUANTUM DISSIPATION; EXCITON MOTION; BAND THEORY; TRANSPORT; DYNAMICS; FLUCTUATIONS AB The fundamental problem of the effects of strong interactions with lattice vibrations on quasiparticle transport is analyzed with the help of the memory-function approach introduced many years ago in the context of exciton and charge transport in molecular aggregates. Comparison is made among the exact evolution in a simplified system, the predictions of the memory approach, and evolution based on semiclassical arguments. It is shown that, for a number of physically relevant parameter ranges, the memory approach provides an excellent representation of the exact evolution while the semiclassical approach does not. A quantum yield experiment appropriate to sensitized luminescence is examined in the light of the tract evolution and the various approximations. Three physical systems are also discussed. They involve charge transport in aromatic hydrocarbon crystals, thermal conduction in refractory materials, and vibrational energy transfer in biological systems. C1 UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Kenkre, VM (reprint author), UNIV NEW MEXICO,CTR ADV STUDIES,ALBUQUERQUE,NM 87131, USA. NR 63 TC 14 Z9 14 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5407 EP 5419 DI 10.1103/PhysRevB.53.5407 PG 13 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100064 ER PT J AU Tober, ED Ynzunza, RX Westphal, C Fadley, CS AF Tober, ED Ynzunza, RX Westphal, C Fadley, CS TI Relationship between morphology and magnetic behavior for Gd thin films on W(110) SO PHYSICAL REVIEW B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; CURIE-TEMPERATURE; SURFACE; GADOLINIUM; GD(0001); RECONSTRUCTION; THICKNESS; GROWTH; TB AB We have used scanning-tunneling microscopy to study the structure of Gd thin films grown on W(110) and its relationship to the magnetic properties. The film morphology is examined for different coverages and for two different post-deposition annealing temperatures (530 and 710 K), permitting predictions of the in-plane demagnetization factor and the Curie temperature that are in excellent agreement with prior ac magnetic-susceptibility measurements. The first monolayer of Gd is also found to grow in a (7 x 14) lateral superstructure, giving rise to in-plane lattice distortions of similar to 1% as compared to the values of bulk Gd. C1 LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Tober, ED (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, USA. NR 22 TC 65 Z9 65 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5444 EP 5448 DI 10.1103/PhysRevB.53.5444 PG 5 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100068 ER PT J AU Movshovich, R Lawrence, JM Hundley, MF Neumeier, J Thompson, JD Lacerda, A Fisk, Z AF Movshovich, R Lawrence, JM Hundley, MF Neumeier, J Thompson, JD Lacerda, A Fisk, Z TI Magnetism in CePtPb SO PHYSICAL REVIEW B LA English DT Article ID HEAVY-FERMION COMPOUNDS; NEUTRON-SCATTERING; TEMPERATURE; PRESSURE; BEHAVIOR AB We report the behavior of the hexagonal compound CePtPb, which has an antiferromagnetic transition at T-N=0.9 K. The magnetic susceptibility is highly anisotropic, with the ratio chi(ab)/chi(ac) extrapolating to the value 65 at T-N. The low-temperature magnetization is also anisotropic with M(ab), saturating to 0.92 mu(B)/Ce atom at B=5 T, where M(c) is five times smaller. The anisotropy is due both to low-symmetry crystal fields and to exchange anisotropy, which causes basal plane ferromagnetic fluctuations to develop below T approximate to 15 K. Three facts suggest that the magnetic order might coexist with heavy-fermion behavior: heat-capacity data show a linear-in-temperature contribution gamma approximate to 300 mJ/mol K-2 in the antiferromagnetic state; the resistivity is quadratic in temperature below T-N; and the magnetic entropy is generated very slowly with temperature reaching a value of only 0.7R ln2 at T=2T(N). On the other hand, the long high-temperature tail of the heat-capacity data correlates with the ferromagnetic fluctuations above T-N; and ac susceptibility measurements under hydrostatic pressure (to 17 kbar) show that T,increases with pressure at an approximate rate 20 mK/kbar, which suggests that CePtPb sits in the small J limit of the Doniach phase diagram; hence heavy-fermion effects may be negligible. C1 NATL HIGH MAGNET FIELD LAB,LOS ALAMOS,NM 87545. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717. RP Movshovich, R (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 15 TC 12 Z9 12 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5465 EP 5471 DI 10.1103/PhysRevB.53.5465 PG 7 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100071 ER PT J AU Chaiken, A Michel, RP Wall, MA AF Chaiken, A Michel, RP Wall, MA TI Structure and magnetism of Fe/Si multilayers grown by ion-beam sputtering SO PHYSICAL REVIEW B LA English DT Article ID X-RAY-DIFFRACTION; GIANT MAGNETORESISTANCE; FE FILMS; SUPERLATTICES; LAYER; REFINEMENT; MIRRORS; ALLOYS; IRON AB Ion-beam sputtering has been used to prepare Fe/Si multilayers on a variety of substrates and over a wide range of temperatures. Small-angle x-ray-diffraction and transmission electron microscopy experiments show that the layers are heavily intermixed although a composition gradient is maintained. When the spacer layer is an amorphous iron silicide, the magnetic properties of the multilayers are similar to those of bulk Fe. When the spacer layer is a crystalline silicide with the B2 or DO3 structure, the multilayers show antiferromagnetic interlayer coupling like that observed in ferromagnet/paramagnet multilayers such as Fe/Cr and Co/Cu. Depending on the substrate type and the growth temperature, the multilayers grow in either the (011) or (001) texture. The occurrence of the antiferromagnetic interlayer coupling is dependent on the crystallinity of the iron and iron silicide layers, but does not seem to be strongly affected by the perfection of the layering or the orientation of the film. Since the B2- and DO3-structure FexSi1-x compounds are known to be metallic, antiferromagnetic interlayer coupling in Fe/Si multilayers probably originates from the same quantum-well and Fermi surface effects as in Fe/Cr and Co/Cu multilayers. RP Chaiken, A (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV MAT SCI & TECHNOL,LIVERMORE,CA 94551, USA. NR 47 TC 122 Z9 123 U1 1 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5518 EP 5529 DI 10.1103/PhysRevB.53.5518 PG 12 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100077 ER PT J AU Rathnayaka, KDD Naugle, DG Cho, BK Canfield, PC AF Rathnayaka, KDD Naugle, DG Cho, BK Canfield, PC TI Anisotropic magnetoresistance of single-crystal HoNi2B2C and the interplay of magnetic and superconducting order SO PHYSICAL REVIEW B LA English DT Article AB The in-plane resistivity and magnetization measurements as a function of the magnitude and direction of the magnetic field and the temperature are reported for single-crystal samples of the HoNi2B2C magnetic superconductor. Features corresponding to several distinct magnetic phases and the coexistence of superconductivity with two of the magnetic phases are observed. Contrary to previous measurements for polycrystalline samples, reentrant superconductivity is not observed in the absence of a field for these samples. The measurements indicate an extremely rich interplay between superconductivity and different magnetic structures that can be influenced by field, temperature, and current. The results correlate quantitatively with and complement previous determinations of the magnetic phase diagram and qualitatively with determinations of the superconducting phases by measurements of the single-crystal magnetization and heat capacity. HoNi2B2C is highly anisotropic, and phase diagrams for the field along the (100) and (001) directions are presented. C1 IOWA STATE UNIV SCI & TECHNOL,AMES,IA 50011. AMES LAB,AMES,IA 50011. RP Rathnayaka, KDD (reprint author), TEXAS A&M UNIV,DEPT PHYS,COLLEGE STN,TX 77843, USA. RI Canfield, Paul/H-2698-2014 NR 31 TC 90 Z9 90 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5688 EP 5695 DI 10.1103/PhysRevB.53.5688 PG 8 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100095 ER PT J AU Norman, MR Hirschfeld, PJ AF Norman, MR Hirschfeld, PJ TI Heat transport and the nature of the order parameter in superconducting UPt3 SO PHYSICAL REVIEW B LA English DT Article ID RESONANT IMPURITY SCATTERING; UPPER CRITICAL-FIELD; FERMION SUPERCONDUCTORS; ANISOTROPIC SUPERCONDUCTORS; WAVE-SUPERCONDUCTORS; SURFACE; STATES AB Recent thermal conductivity data on the heavy fermion superconductor UPt3, have been interpreted as offering support for an E(2u) model of the order parameter as opposed to an E(1g) model. In this paper, we analyze this issue from a theoretical standpoint including the detailed effects of Fermi surface and gap anisotropy. Our conclusion is that although current data put strong constraints on the gap anisotropy, they cannot definitively distinguish between these two models. Measurements on samples of varying quality could be decisive in this regard, however. C1 UNIV FLORIDA, DEPT PHYS, GAINESVILLE, FL 32611 USA. RP ARGONNE NATL LAB, DIV MAT SCI, 9700 S CASS AVE, ARGONNE, IL 60439 USA. RI Hirschfeld, Peter /A-6402-2010; Norman, Michael/C-3644-2013 NR 36 TC 52 Z9 52 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 MAR 1 PY 1996 VL 53 IS 9 BP 5706 EP 5715 DI 10.1103/PhysRevB.53.5706 PG 10 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100097 ER PT J AU Benkraouda, M Clem, JR AF Benkraouda, M Clem, JR TI Magnetic hysteresis from the geometrical barrier in type-II superconducting strips SO PHYSICAL REVIEW B LA English DT Article ID DISK-SHAPED SUPERCONDUCTORS; FLAT SUPERCONDUCTORS; SURFACE-BARRIER; CURRENT-DENSITY; CRITICAL STATE; FIELD AB The magnetic hysteresis due to the geometrical barrier in a type-II superconducting strip placed in a perpendicular applied field is examined theoretically. We first consider ideal strips with no bulk pinning and show results for the average flux density as a function of the applied field for both flux entry and exit. The magnetization is found to be nearly inversely proportional to the applied field upon flux entry and to be proportional to the applied field upon flux exit. We also present results showing the time evolution of magnetic-flux and current-density profiles during initial flux entry for samples that are bulk-pinning free and those with pinning characterized by a critical current J(c). As predicted theoretically in pinning-free strips, the vortices collect in a dome-shaped magnetic flux profile, within which the current density is zero. A vortex-free region develops near the edges, where a high current density flows. With bulk pinning, the vortices pile up in two symmetric dome-shaped magnetic flux profiles, within which the current density is equal to the critical current density, whereas the regions near the center and the edges of the strip remain vortex-free. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Benkraouda, M (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 24 TC 124 Z9 125 U1 1 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5716 EP 5726 DI 10.1103/PhysRevB.53.5716 PG 11 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100098 ER PT J AU Xu, M Ostenson, JE Finnemore, DK Kramer, MJ Fendrich, JA Hettinger, JD Welp, U Crabtree, GW Dabrowski, B Zhang, K AF Xu, M Ostenson, JE Finnemore, DK Kramer, MJ Fendrich, JA Hettinger, JD Welp, U Crabtree, GW Dabrowski, B Zhang, K TI Comparison of superconducting flux pinning due to ion irradiation and effects effects SO PHYSICAL REVIEW B LA English DT Article ID COLUMNAR DEFECTS; CRYSTALS AB Heavy-ion irradiation experiments have been carried out for single crystals of YBa2Cu4O8 in order to compare the magnetic-field dependence of the flux pinning for damage channels with the intrinsic ''fishtail'' pinning that occurs in this material before irradiation The two pinning effects seem to be additive in that irradiation increases the hysteresis at all fields and the fishtail hump persists in the irradiated samples with roughly the same magnitude as before the damage channels are produced. For irradiated samples, there are two regions where pinning rises with increasing field, one near zero field due to a matching effect of the defect density with the vortex lattice spacing and a second at the same field as the original fishtail. Both effects appear in the same sample in different magnetic-field ranges. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,DEPT PHYS,AMES,IA 50011. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115. UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. RP Xu, M (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,US DEPT ENERGY,AMES,IA 50011, USA. NR 9 TC 13 Z9 13 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 9 BP 5815 EP 5817 DI 10.1103/PhysRevB.53.5815 PG 3 WC Physics, Condensed Matter SC Physics GA UA011 UT WOS:A1996UA01100104 ER PT J AU Detlefs, C Goldman, AI Stassis, C Canfield, PC Cho, BK Hill, JP Gibbs, D AF Detlefs, C Goldman, AI Stassis, C Canfield, PC Cho, BK Hill, JP Gibbs, D TI Magnetic structure of GdNi2B2C by resonant and nonresonant x-ray scattering SO PHYSICAL REVIEW B LA English DT Article ID POLARIZATION; ERBIUM AB Resonant and nonresonant x-ray magnetic scattering techniques have been used to study the low-temperature magnetic structure of GdNi2B2C. Taken together, these measurements allow a determination of the ordered moment direction and its evolution with temperature from a single orientation of the sample. The experimental results show that below approximately 19.4 K this compound forms an incommensurate antiferromagnetic state with a magnetic wave vector of approximately 0.55a(star) (b(star)) in the basal plane of the tetragonal structure. Between 19.4 and 13.6 K, the ordered moment is along the b (a) axis. Below approximately 13.6 K an ordered component of the moment develops along the c axis. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP Detlefs, C (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Detlefs, Carsten/B-6244-2008; Canfield, Paul/H-2698-2014 OI Detlefs, Carsten/0000-0003-2573-2286; NR 34 TC 71 Z9 71 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 10 BP 6355 EP 6361 DI 10.1103/PhysRevB.53.6355 PG 7 WC Physics, Condensed Matter SC Physics GA TZ773 UT WOS:A1996TZ77300049 ER PT J AU Bulaevskii, LN Maley, M Safar, H Dominguez, D AF Bulaevskii, LN Maley, M Safar, H Dominguez, D TI Angular dependence of c-axis plasma frequency and critical current in Josephson-coupled superconductors at high fields SO PHYSICAL REVIEW B LA English DT Article ID LAYERED SUPERCONDUCTORS; VORTICES AB A vortex structure is predicted for Josephson-coupled superconductors in strong magnetic fields oriented near ab plane. The c axis component of the field forms an almost triangular pancake lattice inside the layers with the pancakes arranged in a zigzag structure along the c axis. This zigzag structure results in a sharp increase of the c-axis critical current and plasma frequency when the magnetic field deviates from ab orientation. These predictions are confirmed experimentally. RP Bulaevskii, LN (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Dominguez, Daniel/E-9304-2016 OI Dominguez, Daniel/0000-0002-6204-0150 NR 12 TC 54 Z9 54 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 10 BP 6634 EP 6637 DI 10.1103/PhysRevB.53.6634 PG 4 WC Physics, Condensed Matter SC Physics GA TZ773 UT WOS:A1996TZ77300082 ER PT J AU Dominguez, D Bulaevskii, L Ivlev, B Maley, M Bishop, AR AF Dominguez, D Bulaevskii, L Ivlev, B Maley, M Bishop, AR TI Interaction of vortices with ultrasound and the acoustic Faraday effect in type-II superconductors SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; VORTEX STATE; MIXED-STATE; THERMAL FLUCTUATIONS; PHASE-TRANSITIONS; SIGN REVERSAL; FLUX CREEP; LATTICE; LINE; ATTENUATION AB We study the interaction of sound waves with vortices in type-II superconductors, taking into account pinning and electrodynamic forces between vortices and crystal displacements. We propose ultrasound techniques as a method for obtaining information about vortex dynamics. This is particularly appropiate at low temperatures where transport measurements are ineffective. The changes in sound velocity and attenuation due to vortices, can provide information on the elastic constants of the vortex system and on vortex dissipation, respectively. At low temperatures the Magnus force acting on vortices leads to the acoustic Faraday effect: there is a rotation of the polarization plane of tranverse sound waves propagating along the magnetic field. This effect is linear in the Magnus force and magnetic field in crystals with equivalent a and b axes for a field parallel to the c axis. We discuss how this effect can be measured by means of either pulse-echo techniques or standing sound waves. Also, we show that an ac electromagnetic field acting on the vortex system can generate ultrasound. We calculate the amplitude of the generated sound waves in the linear regime and compare with recent experiments. C1 LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87545 USA. UNIV AUTONOMA SAN LUIS POSOSI, INST FIS, SAN LUIS POTOSI 78000, MEXICO. RI Dominguez, Daniel/E-9304-2016 OI Dominguez, Daniel/0000-0002-6204-0150 NR 67 TC 12 Z9 12 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 MAR 1 PY 1996 VL 53 IS 10 BP 6682 EP 6692 DI 10.1103/PhysRevB.53.6682 PG 11 WC Physics, Condensed Matter SC Physics GA TZ773 UT WOS:A1996TZ77300087 ER PT J AU SadeMelo, CAR AF SadeMelo, CAR TI Fractional flux quanta in superconducting solenoids SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC-FIELD; ARRAYS; TRANSITION; FRUSTRATION; ELECTRONS; NETWORK AB The quantization of flux quanta in superconductors is revisited and analyzed in a new topology. The topology is that of a superconducting wire that winds N times around a fixed axis and has its end connected back to its beginning, thus producing an N-loop short circuited solenoid. In this case, fractional flux quanta can be measured through the center of the solenoid, provided that its cross-section radius is small enough. The Little-Parks experiment for an identical topology is discussed. The period of oscillation of the transition temperature of the wire is found to vary as 1/N in units of flux Phi relative to the flux quantum Phi(0). RP SadeMelo, CAR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 23 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 10 BP R6010 EP R6013 PG 4 WC Physics, Condensed Matter SC Physics GA TZ773 UT WOS:A1996TZ77300011 ER PT J AU Suh, BJ Borsa, E Torgeson, DR Cho, BK Canfield, PC Johnston, DC Rhee, JY Harmon, BN AF Suh, BJ Borsa, E Torgeson, DR Cho, BK Canfield, PC Johnston, DC Rhee, JY Harmon, BN TI Absence of antiferromagnetic correlations in YNi2B2C SO PHYSICAL REVIEW B LA English DT Article AB The normal-state magnetic and electronic properties of YNi2B2C single crystals have been investigated by detailed B-11 NMR and magnetic-susceptibility measurements. The data are found to be consistent with band theory, with no evidence of Ni local magnetic moments or antiferromagnetic correlations. C1 UNIV PAVIA,DIPARTIMENTO FIS,I-27100 PAVIA,ITALY. IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Suh, BJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Rhee, Joo/D-2987-2011; Canfield, Paul/H-2698-2014 NR 18 TC 43 Z9 43 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1996 VL 53 IS 10 BP R6022 EP R6025 PG 4 WC Physics, Condensed Matter SC Physics GA TZ773 UT WOS:A1996TZ77300014 ER PT J AU McNaughton, MW McNaughton, KH Glass, G Riley, PJ Auer, KH Davis, CA Gulmez, E Hiebert, JC Jeppesen, RH Ransome, RD Spinka, H Sum, V Supek, I Tripard, GE Woolverton, H AF McNaughton, MW McNaughton, KH Glass, G Riley, PJ Auer, KH Davis, CA Gulmez, E Hiebert, JC Jeppesen, RH Ransome, RD Spinka, H Sum, V Supek, I Tripard, GE Woolverton, H TI np-elastic analyzing power A(N0) at 485 and 788 MeV SO PHYSICAL REVIEW C LA English DT Article ID SPIN-CORRELATION PARAMETER; TOTAL CROSS-SECTIONS; ANGULAR-DEPENDENCE; SCATTERING EXPERIMENTS; CM ANGLES; P-P; NUCLEON; ENERGIES; PP->PP; BEAM AB Measurements are reported for the np-elastic analyzing power from 30 degrees to 128 degrees c.m., at 485 and 788 MeV, with a typical precision of 0.005 and absolute accuracy of 2%. Results strengthen the isospin-0 phase-shift analysis, and clarify the absolute normalization of the polarized neutron beam and the isospin-0 inelasticity. C1 UNIV TEXAS,AUSTIN,TX 78712. UNIV NEW MEXICO,LOS ALAMOS,NM 87545. UNIV MANITOBA,TRIUMF,VANCOUVER,BC V6T 2A3,CANADA. BOGAZICI UNIV,BEBEK,ISTANBUL,TURKEY. TEXAS A&M UNIV,COLLEGE STN,TX 77843. UNIV MONTANA,MISSOULA,MT 59812. RUTGERS STATE UNIV,PISCATAWAY,NJ 08855. ARGONNE NATL LAB,ARGONNE,IL 60439. UNIV MANITOBA,WINNIPEG,MB R3T 2N2,CANADA. RUDJER BOSKOVIC INST,ZAGREB,CROATIA. WASHINGTON STATE UNIV,PULLMAN,WA 99164. UNIV CENT ARKANSAS,CONWAY,AR 72032. RP McNaughton, MW (reprint author), LOS ALAMOS NATL LAB,MS J596,LOS ALAMOS,NM 87545, USA. RI Gulmez, Erhan/P-9518-2015 OI Gulmez, Erhan/0000-0002-6353-518X NR 55 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1996 VL 53 IS 3 BP 1092 EP 1097 DI 10.1103/PhysRevC.53.1092 PG 6 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200008 ER PT J AU Savkli, C Tabakin, F Yang, SN AF Savkli, C Tabakin, F Yang, SN TI Multipole analysis of spin observables in vector meson photoproduction SO PHYSICAL REVIEW C LA English DT Article AB A multipole analysis of vector meson photoproduction is formulated as a generalization of the pseudoscalar meson case. Expansion of spin observables in the multipole basis and behavior of these observables near threshold and resonances are examined. C1 NATL TAIWAN UNIV,DEPT PHYS,TAIPEI 10764,TAIWAN. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV NUCL SCI MS70A3307,BERKELEY,CA 94720. RP Savkli, C (reprint author), UNIV PITTSBURGH,DEPT PHYS & ASTRON,PITTSBURGH,PA 15260, USA. NR 9 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 MAR PY 1996 VL 53 IS 3 BP 1132 EP 1142 DI 10.1103/PhysRevC.53.1132 PG 11 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200011 ER PT J AU Wu, GH Teng, LJ Ping, JL Wang, F Goldman, T AF Wu, GH Teng, LJ Ping, JL Wang, F Goldman, T TI Quark delocalization, color screening, and N-N intermediate range attraction: P-waves SO PHYSICAL REVIEW C LA English DT Article ID NUCLEON NUCLEON-INTERACTION; SPIN ORBIT FORCES; ANTIQUARK EXCITATIONS; MODEL; POTENTIALS; RGM AB The quark delocalization and color screening model is used to study the N-N interaction of spin-isospin (00) and (11) channels. The predicted (1)p(1) phase shifts qualitatively fit the phase shift analysis of scattering data. The (3)p(ls), phase shifts are enhanced by the quark delocalization effect, but the (3)p(c) is too strongly repulsive. C1 NANJING NORMAL UNIV,DEPT PHYS,NANJING 210097,PEOPLES R CHINA. NANJING UNIV,DEPT PHYS,NANJING 210008,PEOPLES R CHINA. NANJING UNIV,CTR THEORET PHYS,NANJING 210008,PEOPLES R CHINA. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Wu, GH (reprint author), SICHUAN UNIV,INST NUCL SCI & TECHNOL,CHENGDU 610064,PEOPLES R CHINA. NR 18 TC 45 Z9 55 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 MAR PY 1996 VL 53 IS 3 BP 1161 EP 1166 DI 10.1103/PhysRevC.53.1161 PG 6 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200014 ER PT J AU Laymon, CM Amos, W Burlein, MG Fortune, HT Ekenberg, T Kotwal, A ODonnell, JM Silk, JD Zumbro, JD Morris, CL Seestrom, SJ Dhuga, KS Garnett, R RawoolSullivan, MW Moore, CF Morris, SL Watson, DL AF Laymon, CM Amos, W Burlein, MG Fortune, HT Ekenberg, T Kotwal, A ODonnell, JM Silk, JD Zumbro, JD Morris, CL Seestrom, SJ Dhuga, KS Garnett, R RawoolSullivan, MW Moore, CF Morris, SL Watson, DL TI Pion elastic and inelastic 2(1)(+) scattering on Ni-58,Ni-60,Ni-62,Ni-64 at T-pi=180 MeV SO PHYSICAL REVIEW C LA English DT Article ID MULTIPOLE MATRIX-ELEMENTS; NEUTRON; STATES; PB-208; NUCLEI; RESONANCE; ISOTOPES; RATIOS; SN-118; MODEL AB Angular distributions for pi(+) and pi(-) elastic and inelastic scattering from the Z=28 closed-proton-shell nuclei Ni-58,Ni-60,Ni-62,Ni-64 have been measured at an incident pion kinetic energy of 180 MeV. Values for the neutron and proton matrix elements for the transition to the J(pi)=2(1)(+) state have been extracted using the distorted wave impulse approximation in which the pi(+) and a data were fitted simultaneously and the neutron and proton vibrational transition strengths were treated as free parameters. While all transitions are predominantly collective, extracted values of M(n)/M(p) indicate increasing collectivity as a function of neutron number and are consistent with the collective limit of N/Z for Ni-64. C1 UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NEW MEXICO STATE UNIV,DEPT PHYS,LAS CRUCES,NM 88003. UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712. UNIV YORK,DEPT PHYS,YORK YO1 5DD,N YORKSHIRE,ENGLAND. NR 30 TC 3 Z9 3 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1996 VL 53 IS 3 BP 1167 EP 1172 DI 10.1103/PhysRevC.53.1167 PG 6 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200015 ER PT J AU Crowell, B Chowdhury, P Blumenthal, DJ Freeman, SJ Lister, CJ Carpenter, MP Henry, RG Janssens, RVF Khoo, TL Lauritsen, T Liang, Y Soramel, F Bearden, IG AF Crowell, B Chowdhury, P Blumenthal, DJ Freeman, SJ Lister, CJ Carpenter, MP Henry, RG Janssens, RVF Khoo, TL Lauritsen, T Liang, Y Soramel, F Bearden, IG TI High-K isomers in W-176 and mechanisms of K violation SO PHYSICAL REVIEW C LA English DT Article ID HIGH-SPIN; BARRIER PENETRATION; COLLECTIVE MOTION; ROTATIONAL BANDS; SELECTION; MOMENTS; NUCLEI; STATES; DECAY AB An isomer, with t(1/2)=35+/-10 ns and J,K-pi=14,14(+), has been observed in the nucleus W-176 using the reaction Nd-150(Si-30,4n) at a beam energy of 133 MeV The isomer exhibits an unusual pattern of decay in which the majority of the flux proceeds directly to states with [K]=0, bypassing available levels of intermediate K. This severe breakdown of normal K-selection rules in W-176 is compared with recent observations of K violation in neighboring nuclei, within the framework of proposed theoretical approaches. The available data on these K-violating decays seem to have a consistent explanation in models of K mixing which include large-amplitude fluctuations of the nuclear shape. C1 YALE UNIV,WRIGHT NUCL STRUCT LAB,NEW HAVEN,CT 06511. ARGONNE NATL LAB,ARGONNE,IL 60439. PURDUE UNIV,W LAFAYETTE,IN 47907. RI Freeman, Sean/B-1280-2010; Bearden, Ian/M-4504-2014; Carpenter, Michael/E-4287-2015 OI Freeman, Sean/0000-0001-9773-4921; Bearden, Ian/0000-0003-2784-3094; Carpenter, Michael/0000-0002-3237-5734 NR 50 TC 34 Z9 35 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1996 VL 53 IS 3 BP 1173 EP 1190 DI 10.1103/PhysRevC.53.1173 PG 18 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200016 ER PT J AU Guessous, A Schulz, N Bentaleb, M Lubkiewicz, E Durell, JL Pearson, CJ Phillips, WR Shannon, JA Urban, W Varley, BJ Ahmad, I Lister, CJ Morss, LR Nash, KL Williams, CW Khazrouni, S AF Guessous, A Schulz, N Bentaleb, M Lubkiewicz, E Durell, JL Pearson, CJ Phillips, WR Shannon, JA Urban, W Varley, BJ Ahmad, I Lister, CJ Morss, LR Nash, KL Williams, CW Khazrouni, S TI Prompt gamma-ray spectroscopy of the Mo-104 and Mo-108 fission fragments SO PHYSICAL REVIEW C LA English DT Article AB The level structures of the neutron-rich Mo-104 and Mo-108 nuclei have been investigated by observing prompt gamma rays emitted in the spontaneous fission of Cm-248 With the EUROGAM spectrometer. Levels with spins up to 12HBAR have been observed and gamma branching obtained. The data can be satisfactorily described when Mo-104,Mo-108 are considered as axially symmetric nuclei: in Mo-104, rotational bands based on the ground state, the one-phonon and the two-phonon gamma-vibrational states and a quasiparticle state have been observed, whereas in Mo-108 the information is limited to the yrast band and the one phonon gamma band. C1 UNIV MANCHESTER,DEPT PHYS,MANCHESTER M13 9PL,LANCS,ENGLAND. ARGONNE NATL LAB,ARGONNE,IL 60439. FAC SCI,LAB PHYS NUCL APPL,KEMITRA,MOROCCO. JAGIELLONIAN UNIV,KRAKOW,POLAND. RP Guessous, A (reprint author), UNIV STRASBOURG 1,CTR RECH NUCL,CNRS,INST NATL PHYS NUCL & PHYS PARTICULES,F-67037 STRASBOURG,FRANCE. NR 15 TC 61 Z9 64 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 MAR PY 1996 VL 53 IS 3 BP 1191 EP 1196 DI 10.1103/PhysRevC.53.1191 PG 6 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200017 ER PT J AU Hasegawa, T Hashimoto, O Homma, S Miyachi, T Nagae, T Sekimoto, M Shibata, T Sakaguchi, H Takahashi, T Aoki, K Noumi, H Bhang, H Youn, M Gavrilov, Y Ajimura, S Kishimoto, T Ohkusu, A Maeda, K Sawafta, R Redwine, RP AF Hasegawa, T Hashimoto, O Homma, S Miyachi, T Nagae, T Sekimoto, M Shibata, T Sakaguchi, H Takahashi, T Aoki, K Noumi, H Bhang, H Youn, M Gavrilov, Y Ajimura, S Kishimoto, T Ohkusu, A Maeda, K Sawafta, R Redwine, RP TI Spectroscopic study of B-10(Lambda), C-12(Lambda), Si-28(Lambda), Y-89(Lambda), La-139(Lambda), and Pb-208(Lambda) by the (pi(+),K+) reaction SO PHYSICAL REVIEW C LA English DT Article ID SINGLE-PARTICLE STATES; HYPERNUCLEAR PRODUCTION; LAMBDA-PARTICLE; P-SHELL; NUCLEI; SPECTROMETER; TRANSITIONS; PI+,K+; KEK AB Hypernuclear mass spectra of B-10(Lambda), C-12(Lambda), Si-28(Lambda), Y-89(Lambda), La-139(Lambda), and Pb-208(Lambda) were measured by the (pi(+),K+) reaction with an energy resolution of 2 MeV (FWHM). The experiment was carried out with a 1.06 GeV/c pi(+) beam from the KEK 12-GeV PS and with the superconducting kaon spectrometer (SKS). For light hypernuclei, core-excited states were resolved for the first time. For heavy hypernuclei, peak structure reflecting Lambda shell structure was observed. C1 UNIV TOKYO, INST NUCL STUDY, TANASHI, TOKYO 188, JAPAN. KYOTO UNIV, DEPT PHYS, SAKYO KU, KYOTO 606, JAPAN. NATL LAB HIGH ENERGY PHYS, KEK, TSUKUBA, IBARAKI 305, JAPAN. SEOUL NATL UNIV, DEPT PHYS, SEOUL 151742, SOUTH KOREA. RUSSIAN ACAD SCI, INST NUCL RES, MOSCOW 117312, RUSSIA. OSAKA UNIV, DEPT PHYS, TOYONAKA, OSAKA 660, JAPAN. TOHOKU UNIV, DEPT PHYS, AOBA KU, SENDAI, MIYAGI 98077, JAPAN. BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. MIT, NUCL SCI LAB, CAMBRIDGE, MA 02139 USA. NR 54 TC 152 Z9 156 U1 0 U2 2 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 MAR PY 1996 VL 53 IS 3 BP 1210 EP 1220 DI 10.1103/PhysRevC.53.1210 PG 11 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200020 ER PT J AU Capurro, OA DiGregorio, DE Gil, S Abriola, D diTada, M Niello, JOF Macchiavelli, AO Marti, GV Pacheco, AJ Testoni, JE Tomasi, D Urteaga, I AF Capurro, OA DiGregorio, DE Gil, S Abriola, D diTada, M Niello, JOF Macchiavelli, AO Marti, GV Pacheco, AJ Testoni, JE Tomasi, D Urteaga, I TI Sub- and near-barrier reactions for C-12+Pd-108,Pd-110 and Li-7+In-113,In-115 SO PHYSICAL REVIEW C LA English DT Article ID SUBBARRIER FUSION REACTIONS AB Evaporation-residue and transfer reaction cross sections have been measured for C-12+ Pd-108,Pd-110 and Li-7+ In-113,In-115. The residual nuclei were detected and identified by off-line observation of the gamma rays emitted in their radioactive decays. The 3n evaporation channel is the dominant decay mode following the fusion of C-12+ Pd-110 and Li-7+ In-115 at sub- and near-barrier energies, and C-12+ (108)d acid 7Li+ In-113 at bombarding energies just above the Coulomb barrier The experimental evaporation-residue excitation functions are compared with calculations obtained using simplified coupled-channel and statistical models. In these calculations it is not necessary to include transfer channels to explain the data in the case of C-12+ Pd-110 and C-12+ Pd-108 but they must be taken into account for 7Li+ In-115 and Li-7+ In-113. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Capurro, OA (reprint author), COMIS NACL ENERGIA ATOM,DEPT FIS,LAB TANDAR,AV LIBERTADOR 8250,RA-1429 BUENOS AIRES,DF,ARGENTINA. RI Tomasi, Dardo/J-2127-2015 NR 15 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1996 VL 53 IS 3 BP 1301 EP 1308 DI 10.1103/PhysRevC.53.1301 PG 8 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200031 ER PT J AU Slypen, I Corcalciuc, V Meulders, JP Chadwick, MB AF Slypen, I Corcalciuc, V Meulders, JP Chadwick, MB TI Triton and alpha-particle production in neutron-induced reactions on carbon at E(n)=42.5, 62.7, and 72.8 MeV SO PHYSICAL REVIEW C LA English DT Article ID CROSS-SECTIONS; ENERGY-LEVELS; LIGHT-NUCLEI; IDENTIFICATION; MODEL AB Double-differential cross sections for fast neutron-induced triton and alpha-particle production on carbon are reported at three incident neutron energies: 42.5, 62.7, and 72.8 MeV, complementing our previous results for proton and deuteron emissions. Angular distributions were measured at laboratory angles between 20 degrees and 160 degrees in steps of 10 degrees. Procedures for data taking and data reduction are described. Results for double-differential, energy-differential, and total cross sections are presented. The measurements are compared to existing data and to nuclear model calculations which include preequilibrium and equilibrium decay mechanisms. C1 CATHOLIC UNIV LOUVAIN, INST PHYS NUCL, B-1348 LOUVAIN LA NEUVE, BELGIUM. UNIV CALIF, LAWRENCE LIVERMORE NATL LAB, NUCL DATA GRP, LIVERMORE, CA 94550 USA. NR 38 TC 25 Z9 25 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 MAR PY 1996 VL 53 IS 3 BP 1309 EP 1318 DI 10.1103/PhysRevC.53.1309 PG 10 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200032 ER PT J AU deFrance, G Baktash, C Haas, B Nazarewicz, W AF deFrance, G Baktash, C Haas, B Nazarewicz, W TI Rotational inertia of superdeformed nuclei: Intruder orbitals, pairing, and identical bands SO PHYSICAL REVIEW C LA English DT Article ID NEIGHBORING ODD-A; EVEN-EVEN NUCLEI; STATES; REGION AB The phenomenon of identical bands is studied by analyzing the distributions of fractional changes in the dynamical moments of inertia of pairs of bands in superdeformed (SD) nuclei. These distributions are found to exhibit a peak with a centroid at nearly zero. Their widths increase in going from the SD bands in the mass A similar to 150, to the SD bands in the mass similar to 190, and to the normally deformed bands in the rare-earth region. Consequently, there exists a significant excess of identical bands in SD nuclei compared to the normally-deformed nuclei at low spins. This difference may be attributed to the weaker pairing correlations and the stabilizing role of intruder orbitals on the structures of SD bands. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. UNIV TENNESSEE,DEPT PHYS,KNOXVILLE,TN 37996. UNIV WARSAW,INST THEORET PHYS,PL-00681 WARSAW,POLAND. RP deFrance, G (reprint author), UNIV STRASBOURG 1,CTR RECH NUCL,CNRS,IN2P3,F-67037 STRASBOURG,FRANCE. NR 19 TC 26 Z9 26 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD MAR PY 1996 VL 53 IS 3 BP R1070 EP R1073 PG 4 WC Physics, Nuclear SC Physics GA TZ772 UT WOS:A1996TZ77200006 ER PT J AU Rizzo, TG AF Rizzo, TG TI Can we observe weak anomalous couplings of heavy quarks through three-jet events? SO PHYSICAL REVIEW D LA English DT Article ID ELECTRIC-DIPOLE MOMENT; FERMION PAIR PRODUCTION; TOP-QUARK; TAU-LEPTON; QED CORRECTIONS; POLARIZATION; COLLIDERS AB The rates and corresponding jet distributions for the decay Z --> b(b) over barg$ and the process e(+)e(-) --> t(t) over barg$ may be sensitive to anomalous dipolelike couplings of heavy quarks to the photon and Z. In the b-quark case, after updating our previous analysis on the constraints imposed by current experiments on Zb(b) over bar anomalous couplings, we show that the variation of these couplings within their presently allowed ranges leads to rather minor modifications to the standard model expectations for Z --> b(b) over barg$ observables. In the t-quark case, significant deviations from the standard model predictions for t(t) over barg$ production at the Next Linear Collider are possible. RP Rizzo, TG (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 65 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1996 VL 53 IS 5 BP 2326 EP 2336 DI 10.1103/PhysRevD.53.2326 PG 11 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TZ192 UT WOS:A1996TZ19200010 ER PT J AU Hisano, J Moroi, T Tobe, K Yamaguchi, M AF Hisano, J Moroi, T Tobe, K Yamaguchi, M TI Lepton-flavor violation via right-handed neutrino Yukawa couplings in the supersymmetric standard model SO PHYSICAL REVIEW D LA English DT Article ID SUPERGRAVITY; MUON; CONVERSION; PHYSICS; NUCLEI; MASS AB Various lepton-flavor-violating (LFV) processes in the supersymmetric standard model with right-handed neutrino supermultiplets are investigated in detail. It is shown that large LFV rates are obtained when tan beta is large. In the case where the mixing matrix in the lepton sector has a similar structure as the Kobayashi-Maskawa matrix and the third-generation Yukawa coupling is as large as that of the top quark, the branching ratios can be as large as B(mu-->e gamma)similar or equal to 10(-11) and B(tau-->mu gamma)similar or equal to 10(-7), which are within the reach of future experiments. If we assume a large mixing angle solution to the atmospheric neutrino problem, the rate for the process tau-->mu gamma becomes larger. We also discuss the difference between our case and the case of the minimal SU(5) grand unified theory. C1 UNIV CALIF SANTA BARBARA,INST THEORET PHYS,SANTA BARBARA,CA 93106. KEK,THEORY GRP,IBARAKI,OSAKA 305,JAPAN. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. UNIV TOKYO,DEPT PHYS,TOKYO 113,JAPAN. TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 98077,JAPAN. RP Hisano, J (reprint author), TOKYO INST TECHNOL,DEPT PHYS,MEGURO KU,OH OKAYAMA,TOKYO 152,JAPAN. NR 28 TC 535 Z9 535 U1 0 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 MAR 1 PY 1996 VL 53 IS 5 BP 2442 EP 2459 DI 10.1103/PhysRevD.53.2442 PG 18 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TZ192 UT WOS:A1996TZ19200021 ER PT J AU Albright, CH Nandi, S AF Albright, CH Nandi, S TI Construction of an SO(10)xU(1)(F) model of the Yukawa interactions SO PHYSICAL REVIEW D LA English DT Article ID GRAND-UNIFIED THEORIES; SOLAR-NEUTRINO DATA; MASS MATRICES; INVARIANT FUNCTIONS; STANDARD MODEL; FERMION MASSES; OSCILLATIONS; QUARK; UNIFICATION; SUPERSYMMETRY AB We construct a supersymmetric SO(10)XU(1)(F) model of the Yukawa interactions at the grand unification scale from knowledge of a phenomenological set of mass matrices obtained by a previous bottom-up approach. The U(1)(F) family symmetry determines the textures for the Majorana and generic Dirac mass matrices, while the SO(10) symmetry relates each particular element of the up, down, neutrino, and charged lepton Dirac matrices. The dominant second and third family contributions in the Dirac sector are renormalizable, while the remaining contributions to the Dirac mass matrices are of higher order, restricted by the U(1)F family symmetry to a small set of tree diagrams, and mainly complex symmetric. The tree diagrams for the Majorana mass matrix are all nonrenormalizable and of progressively higher order, leading to a nearly geometrical structure. Pairs of 1, 45, 10, and 126 Higgs representations enter with those having large vacuum expectation values breaking the symmetry down to SU(3)(c)XSU(2)(L)XU(l)(Y) near the grand unification scale. In terms of 12 parameters expressed as the Yukawa couplings times vacuum expectation values for the Higgs representations employed, a realistic set of 15 quark and lepton masses (including those for the three heavy right-handed Majorana neutrinos) and eight mixing parameters emerges for the neutrino scenario involving the nonadiabatic conversion of solar neutrinos and the depletion of atmospheric muon neutrinos through oscillations into tau neutrinos. C1 FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. OKLAHOMA STATE UNIV,DEPT PHYS,STILLWATER,OK 74078. RP Albright, CH (reprint author), NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115, USA. OI Albright, Carl/0000-0002-2252-6359 NR 73 TC 18 Z9 18 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD MAR 1 PY 1996 VL 53 IS 5 BP 2699 EP 2711 DI 10.1103/PhysRevD.53.2699 PG 13 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TZ192 UT WOS:A1996TZ19200044 ER PT J AU Landberg, C Adams, GS Chan, C Efstathiadis, E Hackenburg, RW Kramer, MA Lindenbaum, SJ Longacre, RS Vazeri, K Wojtsekhowski, B Wright, A Zhao, K Zhu, Y AF Landberg, C Adams, GS Chan, C Efstathiadis, E Hackenburg, RW Kramer, MA Lindenbaum, SJ Longacre, RS Vazeri, K Wojtsekhowski, B Wright, A Zhao, K Zhu, Y TI Test of the OZI rule in hadroproduction of phi phi and phi K+K- SO PHYSICAL REVIEW D LA English DT Article ID ZWEIG-IIZUKA RULE; MESON PRODUCTION; REACTION PI-P->PHI-PHI-N; P INTERACTIONS; GLUEBALLS; BARYONS; SYSTEM; GEV/C; STATES AB The cross sections for phi phi and phi K+K- production were measured with 8 GeV/c pion and kaon beams to examine the OZI suppression of the reaction pi(-)p --> phi phi n. The measured cross section ratios indicate that this reaction is not suppressed for phi phi invariant masses up to 2.5 GeV/c(2). C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. CUNY CITY COLL,DEPT PHYS,NEW YORK,NY 10031. RP Landberg, C (reprint author), RENSSELAER POLYTECH INST,DEPT PHYS,TROY,NY 12180, USA. NR 34 TC 3 Z9 3 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 MAR 1 PY 1996 VL 53 IS 5 BP 2839 EP 2842 DI 10.1103/PhysRevD.53.2839 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TZ192 UT WOS:A1996TZ19200056 ER PT J AU Abe, K Abt, I Ahn, CJ Akagi, T Allen, NJ Ash, WW Aston, D Bacchetta, N Baird, KG Baltay, C Band, HR Barakat, MB Baranko, G Bardon, O Barklow, T Bazarko, AO BenDavid, R Benvenuti, AC Bienz, T Bilei, GM Bisello, D Blaylock, G Bogart, JR Bolton, T Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Busza, W Calcaterra, A Caldwell, DO Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A CavalliSforza, M Church, E Cohn, HO Coller, JA Cook, V Cotton, R Cowan, RF Coyne, DG DOliveira, A Damerell, CJS DeSangro, R DeSimone, P DellOrso, R Dima, M Du, PYC Dubois, R Eisenstein, BI Elia, R Falciai, D Fan, C Fero, MJ Frey, R Furuno, K Gillman, T Gladding, G Gonzalez, S Hallewell, GD Hart, EL Hasegawa, Y Hedges, S Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Hwang, H Iwasaki, Y Jacques, P Jaros, J Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Karliner, I Kawahara, H Kendall, HW King, ME King, R Kofler, RR Krishna, NM Kroeger, RS Labs, JF Langston, M Lath, A Lauber, JA Leith, DWG Liu, X Loreti, M Lu, A Lynch, HL Ma, J Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T Massetti, R Masuda, H Mazzucato, E McKemey, AK Meadows, BT Messner, R Mockett, PM Moffeit, KC Mours, B Muller, G Muller, D Nagamine, T Nauenberg, U Neal, H Nussbaum, M Ohnishi, Y Osborne, LS Panvini, RS Park, H Pavel, TJ Peruzzi, I Pescara, L Piccolo, M Piemontese, L Pieroni, E Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Rensing, PE Rochester, LS Rothberg, JE Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schneekloth, U Schumm, BA Seiden, A Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Shapiro, SL Sherden, DJ Simopoulos, C Sinev, NB Smith, SR Snyder, JA Stamer, P Steiner, H Steiner, R Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Torrence, E Turk, JD Usher, T Vavra, J Vannini, C Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, SR Waite, AP Watts, SJ Weidemann, AW Whitaker, JS White, SL Wickens, FJ Williams, DA Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Woods, M Word, GB Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zeitlin, C Zhang, Z Zhou, J AF Abe, K Abt, I Ahn, CJ Akagi, T Allen, NJ Ash, WW Aston, D Bacchetta, N Baird, KG Baltay, C Band, HR Barakat, MB Baranko, G Bardon, O Barklow, T Bazarko, AO BenDavid, R Benvenuti, AC Bienz, T Bilei, GM Bisello, D Blaylock, G Bogart, JR Bolton, T Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Busza, W Calcaterra, A Caldwell, DO Calloway, D Camanzi, B Carpinelli, M Cassell, R Castaldi, R Castro, A CavalliSforza, M Church, E Cohn, HO Coller, JA Cook, V Cotton, R Cowan, RF Coyne, DG DOliveira, A Damerell, CJS DeSangro, R DeSimone, P DellOrso, R Dima, M Du, PYC Dubois, R Eisenstein, BI Elia, R Falciai, D Fan, C Fero, MJ Frey, R Furuno, K Gillman, T Gladding, G Gonzalez, S Hallewell, GD Hart, EL Hasegawa, Y Hedges, S Hertzbach, SS Hildreth, MD Huber, J Huffer, ME Hughes, EW Hwang, H Iwasaki, Y Jacques, P Jaros, J Johnson, AS Johnson, JR Johnson, RA Junk, T Kajikawa, R Kalelkar, M Karliner, I Kawahara, H Kendall, HW King, ME King, R Kofler, RR Krishna, NM Kroeger, RS Labs, JF Langston, M Lath, A Lauber, JA Leith, DWG Liu, X Loreti, M Lu, A Lynch, HL Ma, J Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T Massetti, R Masuda, H Mazzucato, E McKemey, AK Meadows, BT Messner, R Mockett, PM Moffeit, KC Mours, B Muller, G Muller, D Nagamine, T Nauenberg, U Neal, H Nussbaum, M Ohnishi, Y Osborne, LS Panvini, RS Park, H Pavel, TJ Peruzzi, I Pescara, L Piccolo, M Piemontese, L Pieroni, E Pitts, KT Plano, RJ Prepost, R Prescott, CY Punkar, GD Quigley, J Ratcliff, BN Reeves, TW Rensing, PE Rochester, LS Rothberg, JE Rowson, PC Russell, JJ Saxton, OH Schalk, T Schindler, RH Schneekloth, U Schumm, BA Seiden, A Sen, S Serbo, VV Shaevitz, MH Shank, JT Shapiro, G Shapiro, SL Sherden, DJ Simopoulos, C Sinev, NB Smith, SR Snyder, JA Stamer, P Steiner, H Steiner, R Strauss, MG Su, D Suekane, F Sugiyama, A Suzuki, S Swartz, M Szumilo, A Takahashi, T Taylor, FE Torrence, E Turk, JD Usher, T Vavra, J Vannini, C Vella, E Venuti, JP Verdier, R Verdini, PG Wagner, SR Waite, AP Watts, SJ Weidemann, AW Whitaker, JS White, SL Wickens, FJ Williams, DA Williams, DC Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Woods, M Word, GB Wyss, J Yamamoto, RK Yamartino, JM Yang, X Yellin, SJ Young, CC Yuta, H Zapalac, G Zdarko, RW Zeitlin, C Zhang, Z Zhou, J TI Test of the flavor independence of strong interactions SO PHYSICAL REVIEW D LA English DT Article ID Z(0) RESONANCE; MONTE-CARLO; QUARKS AB We present a comparison of the strong couplings of light (u, d, and s), c, and b quarks determined from multijet rates in flavor-tagged samples of hadronic Z(0) decays recorded with the SLC Large Detector at the SLAG Linear Collider. Flavor separation on the basis of lifetime and decay multiplicity differences among hadrons containing light, c, and b quarks was made using the SLD precision tracking system. We find alpha(s)(uds)/alpha(s)(all)=0.987+/-0.027(stat)+/-0.022(syst)+/-0.22(theory), alpha(s)(c)/alpha(s)(all)=1.012+/-0.104+/-0.102+/-0.096, and alpha(s)(b)/alpha(s)(all)=1.026+/-0.041+/-0.041+/-0.030. C1 ADELPHI UNIV,GARDEN CITY,NY 11530. IST NAZL FIS NUCL,SEZIONE BIOL,I-40126 BOLOGNA,ITALY. BOSTON UNIV,BOSTON,MA 02215. BRUNEL UNIV,UXBRIDGE UB8 3PH,MIDDX,ENGLAND. CALTECH,PASADENA,CA 91125. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV CALIF SANTA CRUZ,SANTA CRUZ,CA 95064. UNIV CINCINNATI,CINCINNATI,OH 45221. COLORADO STATE UNIV,FT COLLINS,CO 80523. UNIV COLORADO,BOULDER,CO 80309. COLUMBIA UNIV,NEW YORK,NY 10027. IST NAZL FIS NUCL,NAZL FRASCATI LAB,I-44100 FERRARA,ITALY. UNIV ILLINOIS,URBANA,IL 61801. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. MIT,CAMBRIDGE,MA 02139. UNIV MASSACHUSETTS,AMHERST,MA 01003. UNIV MISSISSIPPI,UNIVERSITY,MS 38677. NAGOYA UNIV,CHIKUSA KU,NAGOYA,AICHI 464,JAPAN. UNIV OREGON,EUGENE,OR 97403. IST NAZL FIS NUCL,SEZ PADOVA,I-35100 PADUA,ITALY. UNIV PADUA,I-35100 PADUA,ITALY. IST NAZL FIS NUCL,SEZ PERUGIA,I-06100 PERUGIA,ITALY. UNIV PERUGIA,I-06100 PERUGIA,ITALY. IST NAZL FIS NUCL,SEZ PIZA,I-56100 PISA,ITALY. UNIV PISA,I-56100 PISA,ITALY. RUTGERS STATE UNIV,PISCATAWAY,NJ 08855. RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. SOGANG UNIV,SEOUL,SOUTH KOREA. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. UNIV TENNESSEE,KNOXVILLE,TN 37996. VANDERBILT UNIV,NASHVILLE,TN 37235. UNIV WASHINGTON,SEATTLE,WA 98195. UNIV WISCONSIN,MADISON,WI 53706. YALE UNIV,NEW HAVEN,CT 06511. RP Abe, K (reprint author), TOHOKU UNIV,SENDAI,MIYAGI 980,JAPAN. RI de Sangro, Riccardo/J-2901-2012; de Simone, Patrizia/J-3549-2012; Cavalli-Sforza, Matteo/H-7102-2015; Frey, Raymond/E-2830-2016; Calcaterra, Alessandro/P-5260-2015 OI de Sangro, Riccardo/0000-0002-3808-5455; Frey, Raymond/0000-0003-0341-2636; Calcaterra, Alessandro/0000-0003-2670-4826 NR 20 TC 12 Z9 12 U1 0 U2 3 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 MAR 1 PY 1996 VL 53 IS 5 BP R2271 EP R2275 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TZ192 UT WOS:A1996TZ19200001 ER PT J AU Hoover, WG Kum, O Posch, HA AF Hoover, WG Kum, O Posch, HA TI Time-reversible dissipative ergodic maps SO PHYSICAL REVIEW E LA English DT Article ID CHAOS AB We construct especially simple families of piecewise-linear two-dimensional continuous maps. These maps generate sets of points resembling continuous dynamical trajectories sampled at discrete times. The generated sets of points share many properties with nonequilibrium many-body phase-space trajectories. These characteristic properties include (i) time reversibility, (ii) multifractal attractor-repellor pairs, and (iii) ergodicity, without stable fixed points or holes. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. UNIV VIENNA,INST EXPTL PHYS,A-1090 VIENNA,AUSTRIA. RP Hoover, WG (reprint author), UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA, USA. NR 20 TC 23 Z9 23 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1996 VL 53 IS 3 BP 2123 EP 2129 DI 10.1103/PhysRevE.53.2123 PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA UA371 UT WOS:A1996UA37100022 ER PT J AU Ferer, M Gump, JC Smith, DH AF Ferer, M Gump, JC Smith, DH TI Fractal nature of viscous fingering in three-dimensional pore-level models SO PHYSICAL REVIEW E LA English DT Article ID 2-DIMENSIONAL POROUS-MEDIA; FINITE VISCOSITY RATIO; 2-PHASE FLOW; GROWTH; SIMULATIONS; ELECTRODEPOSITS; DEPOSITION; CROSSOVER AB Using three-dimensional pore-level models of random porous media, we have studied viscous fingering in ''two-phase,'' miscible how. When the viscosity ratio M (= mu(D)/mu(I)), the ratio of the viscosity of the displaced fluid to that of the injected fluid, is infinite, the how is known to be modeled by diffusion-limited aggregation (DLA). We have observed and characterized the crossover from fractal how at short times or large viscosity ratios to compact (i.e., Euclidean) how at later times. In our pore-level model of three-dimensional how in the limit of infinite capillary number (zero surface tension), the low viscosity fluid is injected at constant, pressure on one face of the model porous medium. This modeling shows that this how is fractal for large viscosity ratios (M = 10 000), consistent with DLA. For realistic viscosities (M=30-1000), our modeling of the unstable how shows that, although the flows are initially fractal, they become linear on a time scale tau, increasing as tau = tau(o)M(0.16). This characteristic crossover time predicts that the how become compact for patterns larger than a characteristic length, which increases with viscosity ratio as l = l(o)M(0.16/(Dj-2)), where D-f is the fractal dimension. Once compact, the saturation front advances as x approximate to v(o)M(0.16)t; the factor M(0.16) acts as a three-dimensional Koval factor. C1 US DOE,MORGANTOWN ENERGY TECHNOL CTR,MORGANTOWN,WV 26507. RP Ferer, M (reprint author), W VIRGINIA UNIV,DEPT PHYS,POB 6315,MORGANTOWN,WV 26506, USA. NR 35 TC 17 Z9 17 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 MAR PY 1996 VL 53 IS 3 BP 2502 EP 2508 DI 10.1103/PhysRevE.53.2502 PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA UA371 UT WOS:A1996UA37100068 ER PT J AU Cohen, BI Dimits, AM Stimson, JJ Barnes, DC AF Cohen, BI Dimits, AM Stimson, JJ Barnes, DC TI Implicit-moment, partially linearized particle simulation of kinetic plasma phenomena SO PHYSICAL REVIEW E LA English DT Article ID DRIFT INSTABILITIES; TOKAMAKS; CODE AB An algorithm for kinetic simulation of electron and ion plasmas is introduced that combines both implicit and perturbative methods to deal efficiently with disparate time scales and signal-to-noise issues associated with particle discreteness. The algorithm is introduced for an electrostatic model in a strong magnetic field with gyrokinetic ions and drift-kinetic electrons. Some of the numerical dispersion properties are analyzed and confirmed in test simulations. Two-dimensional applications of the algorithm to drift-wave instabilities excited either by an ion temperature gradient (ion-temperature-gradient instability) or by electron inverse Landau damping in the presence of a density gradient (collisionless drift instability) are presented that illustrate the usefulness of the method. Clear gains in resolution and computational efficiency over previous methods are achieved. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Cohen, BI (reprint author), UNIV CALIF,LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 29 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 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1996 VL 53 IS 3 BP 2708 EP 2716 DI 10.1103/PhysRevE.53.2708 PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA UA371 UT WOS:A1996UA37100090 ER PT J AU Fernandez, JC Cobble, JA Failor, BH Hsing, WW Rose, HA Wilde, BH Bradley, KS Gobby, PL Kirkwood, R Kornblum, HN Montgomery, DS Wilke, MD AF Fernandez, JC Cobble, JA Failor, BH Hsing, WW Rose, HA Wilde, BH Bradley, KS Gobby, PL Kirkwood, R Kornblum, HN Montgomery, DS Wilke, MD TI Dependence of stimulated Brillouin scattering on laser intensity, laser f number, and ion species in hohlraum plasmas SO PHYSICAL REVIEW E LA English DT Article ID RAMAN; WAVELENGTH; TARGETS; LIGHT AB Stimulated Brillouin scattering has been studied in plasma conditions approaching those expected within laser-driven cavities (hohlraums) capable of driving a fusion capsule to ignition with x rays. These conditions are achieved using a gas-filled hohlraum design that was fielded at the Nova laser. As the intensity of an interaction beam (351 nm in wavelength) is increased above an onset value I-c, the measured Brillouin backscatter into the lens rises sharply and saturates. I-c decreases as the optic f number increases. The saturation level depends on the gas ion species. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. PHYS INT CO,SAN LEANDRO,CA 94577. RP Fernandez, JC (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. RI Fernandez, Juan/H-3268-2011; OI Fernandez, Juan/0000-0002-1438-1815; Montgomery, David/0000-0002-2355-6242 NR 27 TC 30 Z9 30 U1 0 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1996 VL 53 IS 3 BP 2747 EP 2750 DI 10.1103/PhysRevE.53.2747 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA UA371 UT WOS:A1996UA37100096 ER PT J AU Carlsten, BE Russell, SJ AF Carlsten, BE Russell, SJ TI Subpicosecond compression of 0.1-1 nC electron bunches with a magnetic chicane at 8 MeV SO PHYSICAL REVIEW E LA English DT Article AB After compressing electron bunches with a half-meter long, four-dipole chicane at 8 MeV, we have measured full width at half maximum (FWHM) bunch lengths of less than 1 ps for charges from 0.1 to 1.1 nC. The uncompressed FWHM bunch lengths varied from 10 to 20 ps, and we achieved compression ratios in excess of 40 and peak currents greater than 1 kA. Bunch lengths for low charges were measured using a transversely deflecting rf cavity; bunch lengths for high charges were inferred from the energy spread induced in the beam by its longitudinal space-charge force as it drifted from the end of the compressor to the spectrometer. RP Carlsten, BE (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 11 TC 36 Z9 36 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1996 VL 53 IS 3 BP R2072 EP R2075 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA UA371 UT WOS:A1996UA37100015 ER PT J AU Brizard, AJ AF Brizard, AJ TI Variational structure for dissipationless linear drift-wave equations SO PHYSICS OF PLASMAS LA English DT Article ID GYROKINETIC EQUATIONS AB A derivation from first principles of the Lagrangian density for the dissipationless linear drift-wave equation recently introduced by Mattor and Diamond [Phys. Plasmas 1, 4002 (1994)] is presented. An exact wave-action conservation law for linear drift waves propagating in a rotating magnetized plasma is then derived from the Lagrangian density without requiring the use of the eikonal representation for the wave fields. (C) 1996 American Institute of Physics. RP Brizard, AJ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. OI Brizard, Alain/0000-0002-0192-6273 NR 16 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 744 EP 748 DI 10.1063/1.871808 PG 5 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700005 ER PT J AU Reiman, A AF Reiman, A TI Singular surfaces in the open field line region of a diverted tokamak SO PHYSICS OF PLASMAS LA English DT Article ID 3-DIMENSIONAL KINEMATIC RECONNECTION; NULLS AB The structure of the open field lines of a slightly nonaxisymmetric, poloidally diverted tokamak is explored by numerical integration of the field line equations for a simple model field. In practice, the nonaxisymmetry could be produced self-consistently by the nonlinear evolution of a free-boundary magnetohydrodynamic (MHD) mode, or it could be produced by field errors, or it could be imposed externally by design. In the presence of a nonaxisymmetric perturbation, the tokamak is shown to develop open field line regions of differing topology separated by singular surfaces. It is argued that the singular surfaces can be expected to play a role analogous to that of rational toroidal flux surfaces, in terms of constraining ideal MHD perturbations and thus constraining the free-energy that can be tapped by ideal MHD instabilities. The possibility of active control of free-boundary instabilities by means of currents driven on the open singular surfaces, which are directly accessible from the divertor plates, is discussed. (C) 1996 American Institute of Physics. RP Reiman, A (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,JAMES FORRESTAL CAMPUS,POB 451,PRINCETON,NJ 08543, USA. NR 21 TC 15 Z9 15 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 906 EP 913 DI 10.1063/1.871795 PG 8 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700021 ER PT J AU Shaing, KC Yokoyama, M Wakatani, M Hsu, CT AF Shaing, KC Yokoyama, M Wakatani, M Hsu, CT TI An approximate analytic expression for plasma viscosity in finite aspect ratio tokamaks and its applications SO PHYSICS OF PLASMAS LA English DT Article ID TOROIDAL CONFINEMENT SYSTEMS; TRANSPORT-COEFFICIENTS; NEOCLASSICAL TRANSPORT AB An approximate analytic expression for plasma viscosity in finite aspect ratio tokamaks is constructed from all the asymptotic limits. The resultant viscosity coefficient is compared with the numerical results of the solution of the linearized drift kinetic equation. Neoclassical fluxes are reformulated in terms of the viscosity and friction coefficients. These fluxes can be employed to study the omnigeneous property of high-beta small, or large aspect ratio tokamaks. (C) 1996 American Institute of Physics. C1 KYOTO UNIV,PLASMA PHYS LAB,KYOTO,JAPAN. PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Shaing, KC (reprint author), UNIV TEXAS,INST FUS STUDIES,AUSTIN,TX 78712, USA. NR 12 TC 34 Z9 34 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 965 EP 970 DI 10.1063/1.871801 PG 6 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700027 ER PT J AU Jackson, GL Taylor, TS Lasnier, CJ Leonard, AW Burrell, KH Greenfield, CM Hill, DN Hyatt, AW Kim, J Osborne, TH Strait, EJ Whyte, D Wood, RD AF Jackson, GL Taylor, TS Lasnier, CJ Leonard, AW Burrell, KH Greenfield, CM Hill, DN Hyatt, AW Kim, J Osborne, TH Strait, EJ Whyte, D Wood, RD TI Very high- and high-confinement mode limited discharges in DIII-D SO PHYSICS OF PLASMAS LA English DT Article ID ENERGY CONFINEMENT; TOKAMAK; REGIME AB The first observations of marginally limited very high confinement mode (VH-mode) discharges have been achieved in DIII-D [Nucl. Fusion Special Supplement: World Survey of Activities in Controlled Fusion Research (International Atomic Energy Agency, Vienna, 1990)] with significant reductions in peak heat flux conducted to plasma facing surfaces. In addition, quasistationary well limited high confinement-mode (H-mode) discharges have been obtained in DIII-D, also with reduced peak heat flux. This demonstration of reduced peak heat flux while maintaining high performance, i.e., high energy confinement time, can be important for the design of fusion ignition devices. Energy confinement enhancements in these high triangularity discharges are comparable to diverted discharges with similar parameters: tau(E)/tau(ITER-89P)=2.9 for VH-mode and tau(E)/tau(ITER-89P)=1.8 for quasistationary high confinement mode (H mode), where tau(ITER-89P) is the empirically derived low confinement mode (L-mode) energy confinement scaling relation [Nucl. Fusion 30, 1999 (1990)]. Comparisons of the conducted heat flux, particle flux, and radiated power profiles show a shift toward the inner wall as the discharge configuration becomes more limited. In addition to the advantage of reduced peak heat flux in these limiter discharges, such configurations also allow more effective use of the internal vessel volume, providing the potential for higher performance, i.e., higher plasma current at a fixed safety factor, q(95). (C) 1996 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Jackson, GL (reprint author), GEN ATOM CO,POB 85608,SAN DIEGO,CA 92186, USA. NR 12 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 1005 EP 1011 DI 10.1063/1.871811 PG 7 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700032 ER PT J AU Bezzerides, B Vu, HX Wallace, JM AF Bezzerides, B Vu, HX Wallace, JM TI Convective gain of stimulated Brillouin scattering in long-scale length, two-ion-component plasmas SO PHYSICS OF PLASMAS LA English DT Article ID LIGHT AB The linear kinetic theory is developed for the convective amplification of stimulated Brillouin scattering in a plasma containing two distinct ion species. A computationally tractable expression for the gain coefficient Q is obtained by, first, restricting consideration to growth from the two possible weakly damped ion modes in the two-ion-species plasma and, second, invoking the two-mode approximation for epsilon(-1), the ion response function, in the plasma. Furthermore, a practical procedure is presented for efficiently obtaining Q over the mesh of a large-scale hydrodynamic simulation of a laser-irradiated target. The theory and its application are demonstrated in the simulation of a simple gas target. (C) 1996 American Institute of Physics. RP Bezzerides, B (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 22 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 1073 EP 1090 DI 10.1063/1.871763 PG 18 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700040 ER PT J AU Watt, RG Cobble, J DuBois, DF Fernandez, JC Rose, HA Drake, RP Bauer, BS AF Watt, RG Cobble, J DuBois, DF Fernandez, JC Rose, HA Drake, RP Bauer, BS TI Dependence of stimulated Brillouin scattering on focusing optic F number in long scale-length plasmas SO PHYSICS OF PLASMAS LA English DT Article ID LASER-LIGHT; BEAM; INSTABILITIES; PLANAR; FUSION AB The onset of stimulated Brillouin scattering (SBS) has been examined by varying the effective F number (lens focal length/incident beam diameter) of the optical system used to irradiate a performed 1 mm long, longitudinally uniform hydrocarbon (CH) plasma. SBS onset occurs at higher average laser intensity for smaller F, in qualitative agreement with theory. Quantitative comparison between theory and experiment, and implications for the National Ignition Facility [Phys. Plasmas 2, 2480 (1995)] are discussed. (C) 1996 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Watt, RG (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. RI Fernandez, Juan/H-3268-2011; Drake, R Paul/I-9218-2012 OI Fernandez, Juan/0000-0002-1438-1815; Drake, R Paul/0000-0002-5450-9844 NR 24 TC 21 Z9 21 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 1091 EP 1095 DI 10.1063/1.871764 PG 5 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700041 ER PT J AU Jones, ME Winske, D Goldman, SR Kopp, RA Rogatchev, VG Belkov, SA Gasparyan, PD Dolgoleva, GV Zhidkov, NV Ivanov, NV Kochubej, YK Nasyrov, GF Pavlovskii, VA Smirnov, VV Romanov, YA AF Jones, ME Winske, D Goldman, SR Kopp, RA Rogatchev, VG Belkov, SA Gasparyan, PD Dolgoleva, GV Zhidkov, NV Ivanov, NV Kochubej, YK Nasyrov, GF Pavlovskii, VA Smirnov, VV Romanov, YA TI Modeling ion interpenetration, stagnation, and thermalization in colliding plasmas SO PHYSICS OF PLASMAS LA English DT Article ID 0.44-MU-M LASER-LIGHT; X-RAY GENERATION; RADIATION; COLLISION; TARGETS; SIMULATIONS; CONFINEMENT; WAVELENGTH; 1.3-MU-M; CAVITIES AB Ion interpenetration, stagnation, and energization processes are studied in colliding laser-produced plasma configurations relevant to Trident [R. G. Watt, Rev. Sci. Instrum. 64, 1770 (1993)] experiments using four different numerical methods: one-dimensional Monte Carlo and Lagrangian multifluid codes, and one- and two-dimensional hybrid (particle ions, fluid electrons) and single-fluid Lagrangian codes. Results from the four methodologies are compared for plasmas generated with gold and deuterated polyethylene (CD2) targets. Overall, the various codes give similar results concerning the initial expansion of the plasmas and their collisional interaction, the degree of stagnation, stagnation time, and amount of ion thermalization for gold targets, while multispecies techniques indicate a much softer stagnation for CD2 plasmas than the single-fluid model. Variations in the results of the calculations due to somewhat different initializations and parameters, as well as to different physics in the codes, are discussed. (C) 1996 American Institute of Physics. C1 ALL RUSSIAN SCI RES INST EXPTL PHYS, SARAOV 607200, RUSSIA. RP LOS ALAMOS NATL LAB, POB 1663, LOS ALAMOS, NM 87545 USA. NR 30 TC 17 Z9 17 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 1096 EP 1108 DI 10.1063/1.871765 PG 13 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700042 ER PT J AU Shvets, G Fisch, NJ Rax, JM AF Shvets, G Fisch, NJ Rax, JM TI Relativistic Raman instability shifted by half-plasma frequency SO PHYSICS OF PLASMAS LA English DT Article ID INTENSE LASER-PULSES; ELECTROMAGNETIC-WAVES; GENERATION; ACCELERATION; SCATTERING; EVOLUTION AB A new nonlinear Raman instability in underdense plasma is investigated theoretically. Unlike the usual linear Raman instabilities which grow exponentially in time, this instability takes a finite amount of time to diverge. The explosion time t(infinity) depends on the initial level of the perturbation. A general set of equations for spatio-temporal evolution of the forward nonlinear Raman scattering is derived and its temporal evolution is studied in detail. This new instability results in the generation of forward Raman radiation shifted by half the plasma frequency for laser intensities of order or exceeding 10(18) W/cm(2), something that has been recently observed [A. Modena (private communication, 1995)]. (C) 1996 American Institute of Physics. C1 UNIV PARIS 11,LPGP,F-91495 ORSAY,FRANCE. RP Shvets, G (reprint author), PRINCETON PLASMA PHYS LAB,JAMES FORRESTAL CAMPUS,PRINCETON,NJ 08543, USA. NR 24 TC 6 Z9 6 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 1996 VL 3 IS 3 BP 1109 EP 1112 DI 10.1063/1.871766 PG 4 WC Physics, Fluids & Plasmas SC Physics GA TY097 UT WOS:A1996TY09700043 ER PT J AU Bulaevskii, L Shibaeva, R Lyubovskii, R AF Bulaevskii, L Shibaeva, R Lyubovskii, R TI Igor F. Schegolev - Obituary SO PHYSICS TODAY LA English DT Item About an Individual C1 INST SOLID STATE PHYS,CHERNOGOLOVKA,RUSSIA. INST PHYS CHEM,CHERNOGOLOVKA,RUSSIA. RP Bulaevskii, L (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAR PY 1996 VL 49 IS 3 BP 127 EP 127 DI 10.1063/1.2807563 PG 1 WC Physics, Multidisciplinary SC Physics GA TZ622 UT WOS:A1996TZ62200023 ER PT J AU Nevins, B AF Nevins, B TI Magnetic turnaround for fusion plasmas SO PHYSICS WORLD LA English DT Article RP Nevins, B (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-8585 J9 PHYS WORLD JI Phys. World PD MAR PY 1996 VL 9 IS 3 BP 23 EP 24 PG 2 WC Physics, Multidisciplinary SC Physics GA TY311 UT WOS:A1996TY31100023 ER PT J AU Pynn, R AF Pynn, R TI Tormod Riste 1925-95 SO PHYSICS WORLD LA English DT Item About an Individual RP Pynn, R (reprint author), LOS ALAMOS NEUTRON SCI CTR,LOS ALAMOS,NM, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-8585 J9 PHYS WORLD JI Phys. World PD MAR PY 1996 VL 9 IS 3 BP 67 EP 67 PG 1 WC Physics, Multidisciplinary SC Physics GA TY311 UT WOS:A1996TY31100033 ER PT J AU Wang, N Nobel, PS AF Wang, N Nobel, PS TI Doubling the CO2 concentration enhanced the activity of carbohydrate-metabolism enzymes, source carbohydrate production, photoassimilate transport, and sink strength for Opuntia ficus-indica SO PLANT PHYSIOLOGY LA English DT Article ID SUCROSE-PHOSPHATE SYNTHASE; HIGH ATMOSPHERIC CO2; ELEVATED CO2; WHEAT ENDOSPERM; STARCH; PHOTOSYNTHESIS; ACCLIMATION; LEAVES; PLANT; SUGAR AB After exposure to a doubled CO2 concentration of 750 mu mol mol(-1) air for about 3 months, glucose and starch in the chlorenchyma of basal cladodes of Opuntia ficus-indica increased 175 and 57%, respectively, compared with the current CO2 concentration of 370 mu mol mol(-1), but sucrose content was virtually unaffected. Doubling the CO2 concentration increased the nocturnal malate production in basal cladodes by 75%, inorganic phosphate (Pi) by 32%, soluble starch synthase activity by 30%, and sucrose-Pi synthase activity by 146%, but did not affect the activity of hexokinase. Doubling CO2 accelerated phloem transport of sucrose out of the basal cladodes, resulting in a 73% higher dry weight for the daughter cladodes. Doubling CO2 increased the glucose content in 14-d-old daughter cladodes by 167%, increased nocturnal malate production by 22%, decreased total amino acid content by 61%, and increased soluble starch synthase activity by 30% and sucrose synthase activity by 62%. No downward acclimation of photosynthesis during long-term exposure to elevated CO2 concentrations occurs for O. ficus-indica (M. Cui, P.M. Miller, P.S. Nobel [1993] Plant Physiol 103: 519-524; P.S. Nobel, A.A. Israel [1994] J Exp Bot 45: 295-303), consistent with its higher source capacity and sink strength than under current CO2. These changes apparently do not result in Pi limitation of photosynthesis or suppression of genes governing photosynthesis for this perennial Crassulacean acid metabolism species, as occur for some annual crops. C1 UNIV CALIF LOS ANGELES,DOE LAB,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,DEPT BIOL,LOS ANGELES,CA 90024. NR 48 TC 25 Z9 28 U1 1 U2 6 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD MAR PY 1996 VL 110 IS 3 BP 893 EP 902 PG 10 WC Plant Sciences SC Plant Sciences GA UA599 UT WOS:A1996UA59900021 ER PT J AU Chang, CH Ramshaw, JD AF Chang, CH Ramshaw, JD TI Computational study of high-speed plasma flow impinging on an enthalpy probe SO PLASMA CHEMISTRY AND PLASMA PROCESSING LA English DT Article DE enthalpy probe; supersonic plasma flow; chemical kinetics ID MULTICOMPONENT PLASMAS; AMBIPOLAR DIFFUSION; GAS-MIXTURES; JETS; ARGON AB Enthalpy probe measurements in supersonic plasma flows are subject to various sources of error which are difficult to quantify experimentally. The relative importance of several such errors has been assessed by means of detailed two-dimensional numerical simulations of high-speed plasma flow impinging on an enthalpy probe. The simulations show that moderate uncertainties in upstream pressure and composition (i.e., degree of ionization) can lend to significant errors in the velocity and temperature inferred from the measurements. These errors tend to be larger irt velocity than temperature. A second potential source of error is that enthalpy probe data are generally interpreted by means of simplified analytical relations which neglect the effects of finite-rate ionization, internal electronic excitation, thermal radiation, probe cooling, and probe sampling. The importance of these effects was also assessed, and the resulting errors were not significant under the conditions examined. We conclude that enthalpy probe measurements in supersonic plasma flows are useful in situations where the upstream pressure and degree of ionization are known to reasonable accuracy. RP Chang, CH (reprint author), IDAHO NATL ENGN LAB, POB 1625, IDAHO FALLS, ID 83415 USA. NR 26 TC 11 Z9 12 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4324 EI 1572-8986 J9 PLASMA CHEM PLASMA P JI Plasma Chem. Plasma Process. PD MAR PY 1996 VL 16 IS 1 BP 17 EP 38 DI 10.1007/BF01465215 PG 22 WC Engineering, Chemical; Physics, Applied; Physics, Fluids & Plasmas SC Engineering; Physics GA UD427 UT WOS:A1996UD42700002 ER PT J AU Chang, CH Ramshaw, JD AF Chang, CH Ramshaw, JD TI Modeling of nonequilibrium effects in a high-velocity nitrogen-hydrogen plasma jet SO PLASMA CHEMISTRY AND PLASMA PROCESSING LA English DT Article ID MULTICOMPONENT PLASMAS; AMBIPOLAR DIFFUSION; GAS-MIXTURES; FLOW; AIR AB This paper is dedicated to Professor Emil Pfender on the occasion of his 70th birthday. A numerical simulation has been performed of a high-velocity nitrogen-hydrogen plasma jet in air at atmospheric pressure including finite-rate chemical kinetics. Ions, electrons, and neutral atoms and molecules are treated as separate species in the plasma mixture. The chemical reactions considered are dissociation of molecular species, ionization of atomic species, charge exchange and dissociative recombination of nitrogen, and hydrogen-oxygen reactions. The calculational results show that strong departures from ionization and dissociation equilibrium develop in the downstream region as the chemical reactions freeze out at lower temperatures, in spite of the assumed chemical equilibrium at the nozzle exit. The calculations also show that ionized species are overpopulated throughout the flow, while dissociated species in the core of the jet are underpopulated near the nozzle exit and become overpopulated farther downstream. This initial underpopulation is due to diffusive depletion of dissociated species and enrichment of molecular species in the core of the jet. RP Chang, CH (reprint author), IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 22 TC 34 Z9 34 U1 0 U2 6 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0272-4324 J9 PLASMA CHEM PLASMA P JI Plasma Chem. Plasma Process. PD MAR PY 1996 VL 16 IS 1 SU S BP S5 EP S17 PG 13 WC Engineering, Chemical; Physics, Applied; Physics, Fluids & Plasmas SC Engineering; Physics GA UE066 UT WOS:A1996UE06600002 ER PT J AU Tobin, SJ Hogan, JT DeMichelis, C Klepper, CC Mattioli, M MonierGarbet, P Guilhem, D Hess, WR Isler, RC AF Tobin, SJ Hogan, JT DeMichelis, C Klepper, CC Mattioli, M MonierGarbet, P Guilhem, D Hess, WR Isler, RC TI Global carbon production and transport in Tore Supra SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Letter ID GRAPHITE; TOKAMAK; EROSION AB Impurity production and transport have been studied in small Tore Supra plasmas, for which the sole source of impurities (essentially carbon) is an outboard limiter. The main diagnostic was a visible endoscope, allowing absolute intensity calibrated CCD camera images of the entire limiter to be obtained at selected wavelengths. The experimental results show that, while chemical sputtering is essential to explain the limiter images, it does not contribute much to the central impurity content (for which physical sputtering is more important). The experimental edge carbon fluxes and the core plasma carbon content were simulated by coupling the 3D Monte Carlo edge impurity code BBQ with the ID Tore Supra core impurity transport code, thus modelling (for the first time) the global impurity production and transport. C1 OAK RIDGE NATL LAB,DIV FUS ENERGY,OAK RIDGE,TN 37831. OAK RIDGE INST SCI & EDUC,OAK RIDGE,TN. UNIV MICHIGAN,ANN ARBOR,MI 48109. RP Tobin, SJ (reprint author), CEN CADARACHE,EURATOM ASSOC,CEA FUS CONTROLEE,DRFC,SPPF,F-13108 ST PAUL DURANCE,FRANCE. OI Isler, Ralph/0000-0002-5368-7200 NR 26 TC 12 Z9 12 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1996 VL 38 IS 3 BP 251 EP 263 DI 10.1088/0741-3335/38/3/001 PG 13 WC Physics, Fluids & Plasmas SC Physics GA UE311 UT WOS:A1996UE31100001 ER PT J AU Koslowski, HR Soltwisch, H Stodiek, W AF Koslowski, HR Soltwisch, H Stodiek, W TI Polarimetric measurement of m=1 sawtooth precursor oscillations in the TEXTOR tokamak SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Letter AB The HCN-interferometer/polarimeter on TEXTOR has been extended by a horizontal line of sight in the equatorial plane. The achieved signal to noise ratio and the time resolution of this polarimeter channel are sufficient to resolve the m = 1 magnetic precursor oscillation before the sawtooth collapse. The growth rate of the precursor oscillation in a sawtoothing ohmically heated discharge has been determined to be 600 s(-1). The magnetic perturbation, determined from the Faraday rotation integral, assuming a kink-mode eigenfunction, is 13 mT just before the sawtooth crash and the 'displacement' xi of the core is about 0.9 cm or xi/r(1) = 0.06. The amplitude of a stationary m = 1 mode observed in an additionally heated discharge with balanced neutral beam injection amounts to 26 mT. C1 RUHR UNIV BOCHUM, INST EXPTL PHYS, D-44780 BOCHUM, GERMANY. PRINCETON UNIV, PLASMA PHYS LAB, PRINCETON, NJ 08544 USA. RP Koslowski, HR (reprint author), FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, EURATOM, INST PLASMAPHYS, POSTFACH 1913, D-52425 JULICH, GERMANY. NR 13 TC 12 Z9 12 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1996 VL 38 IS 3 BP 271 EP 278 DI 10.1088/0741-3335/38/3/003 PG 8 WC Physics, Fluids & Plasmas SC Physics GA UE311 UT WOS:A1996UE31100003 ER PT J AU Ongena, J Messiaen, AM Samm, U Unterberg, B Finken, KH Vandenplas, PE VanOost, G VanWassenhove, G Winter, J Bonheure, G Dumortier, P Durodie, F Euringer, H Fuchs, G Hoenen, F Koch, R Konen, L Koslowski, HR KramerFlecken, A Rapp, J Schoon, N Telesca, G Uhlemann, R Vervier, M Waidmann, G Weynants, RR AF Ongena, J Messiaen, AM Samm, U Unterberg, B Finken, KH Vandenplas, PE VanOost, G VanWassenhove, G Winter, J Bonheure, G Dumortier, P Durodie, F Euringer, H Fuchs, G Hoenen, F Koch, R Konen, L Koslowski, HR KramerFlecken, A Rapp, J Schoon, N Telesca, G Uhlemann, R Vervier, M Waidmann, G Weynants, RR TI Confinement transitions with radiation cooling in TEXTOR-94 SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Letter AB New experiments performed at high power with radiation cooling on TEXTOR-94, upgraded for long pulses, have shown the following. (i) Improved confinement conditions at high density (for which the plasma is mainly thermal) lasting for several seconds up to the present maximum flat top time of the upgraded machine with a low and stationary central impurity content. Note that the radiation occurs near the plasma edge, mainly inside the last closed magnetic flux surface. (ii) The existence of confinement transitions during the radiatively cooled phase of the discharge: the already observed transitions from higher to lower confinement regimes have been confirmed but, remarkably, transitions from lower to higher confinement are now also present, leading to an improvement of the confinement time of up to a factor of three. C1 FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, EURATOM, INST PLASMA PHYS, D-52425 JULICH, GERMANY. OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RP Ongena, J (reprint author), EURATOM, ECOLE ROYALE MIL, PLASMA PHYS LAB, B-1040 BRUSSELS, BELGIUM. OI Rapp, Juergen/0000-0003-2785-9280; Unterberg, Bernhard/0000-0003-0866-957X NR 22 TC 16 Z9 16 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1996 VL 38 IS 3 BP 279 EP 288 DI 10.1088/0741-3335/38/3/004 PG 10 WC Physics, Fluids & Plasmas SC Physics GA UE311 UT WOS:A1996UE31100004 ER PT J AU Nishitani, T Hoek, M Harano, H Isobe, M Tobita, K Kusama, Y Wurden, GA Chrien, RE AF Nishitani, T Hoek, M Harano, H Isobe, M Tobita, K Kusama, Y Wurden, GA Chrien, RE TI Triton burn-up study in JT-60U SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID PLASMAS; RIPPLE AB Time-resolved triton burn-up measurements have been performed using a new type of 14 MeV neutron detector based on scintillating fibres. The shot-integrated triton burn-up ratio was measured to be in the range 0.3-2.0%. Time histories of 14 MeV emission after NE turn-off have been analysed based on the classical slowing-down theory. Assuming the loss of fast tritons can be represented as a diffusivity, values increasing with increasing toroidal ripple were determined between 0.05 and 0.15 m(2) s(-1), from the modelling of the time histories of the 14 MeV emission after the NB turn-off. C1 LOS ALAMOS NATL LAB, LOS ALAMOS, NM 87544 USA. RP Nishitani, T (reprint author), JAPAN ATOM ENERGY RES INST, NAKA FUS RES ESTAB, NAKA, IBARAKI 31101, JAPAN. RI Wurden, Glen/A-1921-2017 OI Wurden, Glen/0000-0003-2991-1484 NR 15 TC 16 Z9 16 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1996 VL 38 IS 3 BP 355 EP 364 DI 10.1088/0741-3335/38/3/010 PG 10 WC Physics, Fluids & Plasmas SC Physics GA UE311 UT WOS:A1996UE31100010 ER PT J AU Ruskov, E Heidbrink, WW McCune, D Johnson, L AF Ruskov, E Heidbrink, WW McCune, D Johnson, L TI Evidence for spatially variable beam ion diffusion in TFTR SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID TOROIDAL FIELD RIPPLE; TOKAMAK; CONFINEMENT; PLASMAS AB We present evidence that the fast-ion diffusion coefficient changes across the TFTR plasma column. Two MHD quiescent discharges are analysed: a high power D-T plasma heated with 21 MW of deuterium and tritium beams, and an ohmic plasma into which a 10 MW, 20 ms deuterium beam pulse was injected. The localized charge-exchange measurements in the ohmic plasma, and the neutron Bur measurements in the D-T plasma are compared with predictions from the 1 1/2D transport simulation code TRANSP. We have modified the code to allow modelling with arbitrary fast-ion diffusion profiles D-f(r). Significant improvement in the agreement between measurement and simulation is obtained with a D-f(r) profile that has low values in the inner half of the plasma column (D-f < 0.05 m(2) s(-1)) and then rises rapidly towards the plasma periphery. This suggests a common underlying mechanism of enhanced beam ion transport in the two discharges, such as stochastic ripple diffusion. C1 PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP Ruskov, E (reprint author), UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717, USA. NR 34 TC 5 Z9 5 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1996 VL 38 IS 3 BP 389 EP 403 DI 10.1088/0741-3335/38/3/013 PG 15 WC Physics, Fluids & Plasmas SC Physics GA UE311 UT WOS:A1996UE31100013 ER PT J AU Bosch, HS Erckmann, V Laurent, L Motojima, O Neilson, GH Oktay, E Owens, DK Rau, F Thomassen, KI Wagner, F AF Bosch, HS Erckmann, V Laurent, L Motojima, O Neilson, GH Oktay, E Owens, DK Rau, F Thomassen, KI Wagner, F TI Summary of the workshop on technological aspects of steady-state devices SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Editorial Material ID TORE SUPRA TOKAMAK; DESIGN; SYSTEM AB The major contributions to this workshop came from TORE-SUPRA, TPX, LHD and W7-X (two tokamaks, one heliotron and a stellarator). All four devices are of similar size and designed for a similar range of parameters and, in particular, they address the same target-steady-state plasma operation. TORE-SUPRA is a circular cross section tokamak, LHD is designed with optimized continuous coils and provides a helical divertor, TPX and W7-X incorporate strongly-shaped geometries to improve confinement and stability and optimize the bootstrap current. In TPX, the system is optimized for a large bootstrap current, in W7-X for basically no bootstrap current. Also the heating systems are designed for the specific purpose of steady-state operation. TORE-SUPRA is in operation, LHD is near completion; W7-X has recently (after the workshop) been approved; TPX is still in the approval phase. Superconducting coil material is NbTi for TORE-SUPRA, LHD and W7-X and Nb3Sn for TPX. The TF-coils of TORE-SUPRA (1.8 K, superfluid He) and the helical coil of LHD (4.2 K for the first part of experiments with 3 T) are bath-cooled. Cable-in-conduit conductors are used in the other SC coils. Largely different solutions are selected for the SC cable composition. Except for TPX, which has a double-null poloidal field divertor matched to the strong plasma shaping, most of the steady-state devices have a very flexible plasma edge configuration: islands or ergodic boundaries (W7-X, TORE-SUPRA, LHD), limiter (TORE-SUPRA), helical divertor (LHD, W7-X). The status of plasma equilibrium control, high heat flux materials and activation problems were also discussed. Power plant studies based on different steady-state confinement concepts were presented and confronted with a summary on the PULSAR study based on pulsed systems. C1 EURATOM,CEA,CTR ETUD CADARACHE,CADARACHE,FRANCE. NATL INST FUS SCI,NAGOYA,AICHI,JAPAN. OAK RIDGE NATL LAB,OAK RIDGE,TN. DEPT ENERGY,BASE & ADV TORODAL PROGRAM,WASHINGTON,DC. PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Bosch, HS (reprint author), MAX PLANCK INST PLASMA PHYS,EURATOM ASSOC,IPP,BOLTZMANNSTR 2,W-8046 GARCHING,GERMANY. RI Bosch, Hans-Stephan/F-9527-2015 NR 33 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD MAR PY 1996 VL 38 IS 3 BP 415 EP 449 DI 10.1088/0741-3335/38/3/015 PG 35 WC Physics, Fluids & Plasmas SC Physics GA UE311 UT WOS:A1996UE31100015 ER PT J AU ChangChien, GP Denn, MM AF ChangChien, GP Denn, MM TI Isothermal crystallization kinetics of poly(ethylene terephthalate) in blends with a liquid crystalline polyester (Vectra A) SO POLYMERS FOR ADVANCED TECHNOLOGIES LA English DT Article DE crystallization; blends; liquid-crystalline polymer; Vectra; poly(ethylene terephthalate); melting; differential scanning calorimetry ID POLYETHYLENE TEREPHTHALATE; PET; POLY(ETHYLENE-TEREPHTHALATE); BEHAVIOR; POLYMER AB The isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) in blends with a fully aromatic liquid crystalline copolyester (Vectra A) were studied with differential scanning calorimetry. PET crystallization rates decrease with increasing Vectra fractions in the blend, and the percentage of PET that is crystalline also decreases with increasing Vectra. The equilibrium PET melting temperature for blends containing 40% or more Vectra is unambiguously below that of pure PET. Attenuated total reflectance Fourier-transform infrared spectroscopy measurements indicate that PET/Vectra transesterification does not take place. The results are consistent with a scenario based on prior NMR data in which there is some interphase mixing between the liquid crystalline and flexible polymers and an increase in the fraction of gauche conformers in the PET. C1 CHENG SHIU COLL TECHNOL,DEPT CHEM ENGN,KAOHSIUNG 80741,TAIWAN. UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. NR 18 TC 14 Z9 14 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 1042-7147 J9 POLYM ADVAN TECHNOL JI Polym. Adv. Technol. PD MAR PY 1996 VL 7 IS 3 BP 168 EP 172 DI 10.1002/(SICI)1099-1581(199603)7:3<168::AID-PAT531>3.0.CO;2-H PG 5 WC Polymer Science SC Polymer Science GA UK079 UT WOS:A1996UK07900003 ER PT J AU Smith, VF Schwartz, BL Randall, LL Smith, RD AF Smith, VF Schwartz, BL Randall, LL Smith, RD TI Electrospray mass spectrometric investigation of the chaperone SecB SO PROTEIN SCIENCE LA English DT Article DE chaperone; electrospray mass spectrometry; noncovalent interactions; SecB ID ESCHERICHIA-COLI; IONIZATION; PROTEIN; INVITRO; BINDING; TRANSLOCATION; DISSOCIATION; EXPORT; IONS AB Electrospray ionization mass spectrometry was used to investigate the structure of the Escherichia coli chaperone protein SecB. It was determined that the N-terminal methionine of SecB has been removed and that more than half of all SecB monomers are additionally modified, most likely by acetylation of the N-terminus or a lysine. The use of gentle mass spectrometer interface conditions showed that the predominant, oligomeric form of SecB is a tetramer that is stable over a range of solution pH conditions and mass spectrometer interface heating (i.e., inlet capillary temperatures). At very high pH, SecB dimers are observed. SecB contains a region that is hypersensitive to cleavage by proteinase K and is thought to be involved in conformational changes that are crucial to the function of SecB. We identified the primary site of cleavage to be between Leu 141 and Gin 142. Fourteen amino acids are removed, but the truncated form remains a tetramer with stability similar to that of the intact form. C1 WASHINGTON STATE UNIV, DEPT BIOCHEM & BIOPHYS, PULLMAN, WA 99164 USA. PACIFIC NW LAB, DEPT CHEM SCI, CHEM METHODS & SEPARAT GRP, RICHLAND, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 FU NIGMS NIH HHS [GM29798, T32 GM08336] NR 26 TC 57 Z9 57 U1 0 U2 0 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD MAR PY 1996 VL 5 IS 3 BP 488 EP 494 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TY946 UT WOS:A1996TY94600010 PM 8868485 ER PT J AU FEHNER, TR GOSLING, FG AF FEHNER, TR GOSLING, FG TI WOLF-CREEK-STATION - KANSAS-GAS-AND-ELECTRIC IN THE NUCLEAR ERA - MINER,C SO PUBLIC HISTORIAN LA English DT Book Review RP FEHNER, TR (reprint author), US DOE,WASHINGTON,DC 20545, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU UNIV CALIF PRESS PI BERKELEY PA JOURNALS DEPT 2120 BERKELEY WAY, BERKELEY, CA 94720 SN 0272-3433 J9 PUBL HISTORIAN JI Public Hist. PD SPR PY 1996 VL 18 IS 2 BP 77 EP 79 PG 3 WC History SC History GA UN304 UT WOS:A1996UN30400009 ER PT J AU Comello, V AF Comello, V TI Reducing auto emissions to ultralow levels SO R&D MAGAZINE LA English DT Article RP Comello, V (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CAHNERS-DENVER PUBLISHING CO PI HIGHLANDS RANCH PA 8773 S RIDGELINE BLVD, HIGHLANDS RANCH, CO 80126-2329 SN 0746-9179 J9 R&D MAG JI R D Mag. PD MAR PY 1996 VL 38 IS 4 BP 21 EP 21 PG 1 WC Engineering, Industrial; Multidisciplinary Sciences SC Engineering; Science & Technology - Other Topics GA UB460 UT WOS:A1996UB46000012 ER PT J AU Espinosa, G Gammage, RB Meyer, KE AF Espinosa, G Gammage, RB Meyer, KE TI Response of different polyallyl di-glycol carbonate materials to alpha particles SO RADIATION MEASUREMENTS LA English DT Article ID NUCLEAR-TRACK; SENSITIVITY; RADON; LUNG AB Polyallyl di-glycol carbonate (PADC) is the material most commonly used as an integrating passive alpha track detector. Several manufacturers offer PADC material of varying quality. The results are presented for comparative response to a range of alpha particle energies and variable etching conditions. Seven different types of PADC from three suppliers were evaluated. For each type of PADC material, three different sheets were sampled. Each sheet was cut, codified, and handled in the same way for each set of alpha exposure and etching conditions. The sensitivity to different alpha particle energies, average background, efficiency of alpha particle registration, and linearity of response were compared. The potential was demonstrated for making in situ field measurements of plutonium contaminated soils at the 10 pCi/g level. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Espinosa, G (reprint author), UNIV NACL AUTONOMA MEXICO,INST FIS,APARTADO POSTAL 20-364,MEXICO CITY 01000,DF,MEXICO. NR 9 TC 1 Z9 1 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD MAR PY 1996 VL 26 IS 2 BP 173 EP 177 DI 10.1016/1350-4487(95)00299-5 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA UK504 UT WOS:A1996UK50400004 ER PT J AU Deshpande, A Goodwin, EH Bailey, SM Marrone, BL Lehnert, BE AF Deshpande, A Goodwin, EH Bailey, SM Marrone, BL Lehnert, BE TI Alpha-particle-induced sister chromatid exchange in normal human lung fibroblasts: Evidence for an extranuclear target SO RADIATION RESEARCH LA English DT Article ID CHINESE-HAMSTER CELLS; RESPIRATORY-TRACT; EPITHELIAL-CELLS; RADON PROGENY; X-RAYS; INDUCTION; DNA; RADIATION; IRRADIATION; RADIOBIOLOGY AB We investigated the relationship between nuclear hits by alpha particles and the subsequent occurrence of sister chromatid exchanges (SCEs) in normal human diploid lung fibroblasts (HFL1). Cells were exposed to Pu-238 alpha particles at doses ranging from 0.4-12.9 cGy and subsequently analyzed for SCEs. A significant increase in SCE frequency was observed even at the lowest dose examined. The extent of induction of SCEs in the HFL1 cells showed dose dependency in the very low dose range, i.e. 0.4-2.0 cGy. Thereafter, induction of SCEs was independent of dose. Based on measurements of the nuclear areas of the HFL1 cells in conjunction with target theory calculations, the lowest dose resulted in an similar to 8.6-fold increase in the percentage of cells showing excessive SCEs over the theoretically expected percentage of cells whose nuclei were calculated to be traversed by one or more alpha particles. The extent of the discrepancies between theoretically expected and experimentally observed frequencies of SCEs became progressively reduced with increasing radiation dose. We additionally determined that SCEs induced by the alpha particles have no significant dependency on the time of cell collection after exposure to a selected dose of alpha particles, thereby confirming that the differences between the theoretically predicted and observed SCE frequencies were not due to an artifact of the time of cell sampling for the SCE measurements. These results obtained with normal human cells are similar to those of other investigators who observed excessive SCEs in immortalized rodent cells beyond that which could be attributed exclusively to nuclear traversals by alpha particles. Such consistent findings point to the existence of an alternative, extranuclear target through which alpha particles cause DNA damage, as detected by SCE analysis. The existence of an extranuclear compartment as a target for alpha particles may have important implications for the susceptibility of lung cells to the DNA-damaging effects of alpha-particle exposure due to the inhalation of radon progeny. (C) 1996 by Radiation Research Society RP Deshpande, A (reprint author), LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545, USA. NR 59 TC 227 Z9 243 U1 1 U2 8 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAR PY 1996 VL 145 IS 3 BP 260 EP 267 DI 10.2307/3578980 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA TY619 UT WOS:A1996TY61900002 PM 8927692 ER PT J AU Wu, H Durante, M George, K Goodwin, EH Yang, TC AF Wu, H Durante, M George, K Goodwin, EH Yang, TC TI Rejoining and misrejoining of radiation-induced chromatin breaks .2. Biophysical model SO RADIATION RESEARCH LA English DT Article ID IN-SITU HYBRIDIZATION; HUMAN-FIBROBLASTS; CHROMOSOME-ABERRATIONS; HUMAN-LYMPHOCYTES; DICENTRICS; DAMAGE; CELLS; TRANSLOCATIONS; IRRADIATION; FREQUENCY AB A biophysical model for the kinetics of the formation of radiation-induced chromosome aberrations is developed to account for the recent experimental results obtained with a combination of the premature chromosome condensation (PCC) and fluorescence in situ hybridization (FISH) techniques. In this model, we consider the broken ends of DNA double-strand breaks (DSBs) to be reactant and make use of the interaction distance hypothesis. The repair/misrepair process between broken ends is suggested to consist of two steps; the first step represents the two break ends approaching each other, and the second step represents the enzymatic processes leading to DNA end-to-end rejoining. Only the second step is reflected in the kinetics observed in experiments using PCC. The model appears to be able to fit existing data for human cells, It is shown that the kinetics of the formation of chromosome aberrations can be explained by a single rate that characterizes both rejoining and misrejoining of DSBs, suggesting that repair and misrepair share the same mechanism. Fast repair (completed in minutes) in a subset of DSBs is suggested as an explanation of the complete exchanges observed with PCC in human lymphocytes immediately after irradiation. The fast repair component seems to be absent in human fibroblasts. (C) 1996 by Radiation Research Society C1 NASA,LYNDON B JOHNSON SPACE CTR,RADIAT BIOPHYS LAB,HOUSTON,TX 77058. KRUG LIFE SCI,HOUSTON,TX 77058. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RI Durante, Marco/K-1315-2014; OI Durante, Marco/0000-0002-4615-553X NR 39 TC 20 Z9 20 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAR PY 1996 VL 145 IS 3 BP 281 EP 288 DI 10.2307/3578983 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA TY619 UT WOS:A1996TY61900005 PM 8927695 ER PT J AU Gilbert, ES Cross, FT Dagle, GE AF Gilbert, ES Cross, FT Dagle, GE TI Analysis of lung tumor risks in rats exposed to radon SO RADIATION RESEARCH LA English DT Article AB Using data on 3117 rats exposed by inhalation to radon, radon progeny and uranium ore dust, the hazard function (or age-specific risk) for lung tumor incidence was modeled as a function of exposure, exposure rate and other factors. The overall estimate of lifetime risk was 237 cases per 10(6) rats per WLM (237 per 10(6) WLM), reasonably comparable to estimates obtained from data for humans. The data below 1000 WLM (20-640 WLM) were consistent with linearity with positive excess risks at all levels; however, evidence of statistically significant excess risk was limited to exposures of 80 WLM or greater. Evidence for an inverse exposure-rate effect was limited primarily to cumulative exposures exceeding 1000 WLM (1280-10,240 WLM) and to comparison of results at 100 and 1000 WL. Even at these levels, the possibility that the effect might be explained by time since last exposure or by heterogeneity across experiments could not be entirely excluded. The inverse exposure-rate effect was strongest for epidermoid and adenosquamous tumors, and the only indication of such an effect at exposures below 1000 WLM was modest evidence (P = 0.024) in analyses limited to these tumors. When all lung tumors, or all malignant lung tumors, were included, there was no evidence of such an effect below 1000 WLM. These data support the viewpoint that the inverse exposure-rate effect is primarily a high-dose phenomenon. (C) 1996 by Radiation Research Society C1 WASHINGTON STATE UNIV, US TRANSURANIUM & URANIUM REGISTRIES, RICHLAND, WA 99352 USA. RP Gilbert, ES (reprint author), PACIFIC NW LAB, HLTH PROTECT DEPT, POB 999, RICHLAND, WA 99352 USA. RI WSU, USTUR/I-1056-2013 NR 25 TC 28 Z9 31 U1 0 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD MAR PY 1996 VL 145 IS 3 BP 350 EP 360 DI 10.2307/3578992 PG 11 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA TY619 UT WOS:A1996TY61900014 PM 8927704 ER PT J AU Wright, JW Argo, PE Pitteway, MLV AF Wright, JW Argo, PE Pitteway, MLV TI On the radiophysics and geophysics of ionogram spread F SO RADIO SCIENCE LA English DT Article ID SCINTILLATION THEORY; REGION; DYNASONDE; HF AB We consider the interpretation of ''spread F'' ionograms, particularly those echoes that determine most of the radio bandwidth of the phenomenon. We compare expectations based on total internal reflection with theoretical descriptions based on underdense scattering. We conclude that ''Rayleigh,'' ''Bragg,'' and ''diffuse multiple-refractive'' radio scattering theories are not consistent with observed properties of these echoes. The total-reflection interpretation is shown to be consistent with rocket and satellite data. Evidence for multiple refractive scatter is found, but it neither greatly nor subtly extends the observed radio bandwidth. Ionograms therefore indicate comprehensively the range of plasma densities within view of the ionosonde, even in conditions of spread F. Using digital ionosonde observations, much can be learned of the spatial structures of plasma density responsible for spread F at auroral and equatorial latitudes. As an example, we suggest how contemporary theory and simulations of the equatorial ''bubble'' phenomenon may be reconciled with the distinctive equatorial spread F pattern. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. BRUNEL UNIV,DEPT COMP SCI,UXBRIDGE UB8 3PH,MIDDX,ENGLAND. UNIV WALES,DEPT PHYS,ABERYSTWYTH,DYFED,WALES. NR 34 TC 27 Z9 27 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAR-APR PY 1996 VL 31 IS 2 BP 349 EP 366 DI 10.1029/95RS03104 PG 18 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA UD849 UT WOS:A1996UD84900011 ER PT J AU Seat, JE Wrisberg, CA AF Seat, JE Wrisberg, CA TI The visual instruction system SO RESEARCH QUARTERLY FOR EXERCISE AND SPORT LA English DT Article DE motor skill instruction; movement analysis; video graphics; visual feedback C1 UNIV TENNESSEE,COLL EDUC,CULTURAL STUDIES UNIT,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,OAK RIDGE,TN. NR 2 TC 3 Z9 3 U1 0 U2 0 PU AMER ALLIANCE HEALTH PHYS EDUC REC & DANCE PI RESTON PA 1900 ASSOCIATION DRIVE, RESTON, VA 22091 SN 0270-1367 J9 RES Q EXERCISE SPORT JI Res. Q. Exerc. Sport PD MAR PY 1996 VL 67 IS 1 BP 106 EP 108 PG 3 WC Hospitality, Leisure, Sport & Tourism; Psychology, Applied; Psychology; Sport Sciences SC Social Sciences - Other Topics; Psychology; Sport Sciences GA UN443 UT WOS:A1996UN44300013 PM 8736001 ER PT J AU Williams, M Poyer, D AF Williams, M Poyer, D TI The effect of energy conservation tax credits on minority household housing improvements SO REVIEW OF BLACK POLITICAL ECONOMY LA English DT Article AB This article examines the effects of socioeconomic measures, an array of housing structure characteristics, external temperature conditions, and the role of residential energy tax credits on energy-conservation improvement among black and Hispanic households respectively. We find strong, consistent support that higher income blacks and higher income Hispanics tend to invest in energy saving conservation equipment. Also, while older blacks are less likely to invest, older Hispanics do. Blacks consider housing size in their decision to invest; Hispanics do not. We also find that energy tax credits play a statistically/significant role in explaining energy conservation improvement activity for both blacks and Hispanics. C1 ARGONNE NATL LAB,DIV ENERGY SYST,ARGONNE,IL 60439. RP Williams, M (reprint author), NO ILLINOIS UNIV,DEPT ECON,DE KALB,IL 60115, USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU NATL ECON ASSN ATLANTA UNIV CENTER PI ATLANTA PA 360 WESTVIEW DR SW, ATLANTA, GA 30310 SN 0034-6446 J9 REV BLACK POLIT ECON JI Rev. Black Polit. Econ. PD SPR PY 1996 VL 24 IS 4 BP 123 EP & DI 10.1007/BF02690047 PG 14 WC Economics; Ethnic Studies SC Business & Economics; Ethnic Studies GA XE821 UT WOS:A1996XE82100008 ER PT J AU Dinneen, T Ghiorso, A Gould, H AF Dinneen, T Ghiorso, A Gould, H TI An orthotropic source of thermal atoms SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A source of thermal atoms that emits 100% of its atoms into a narrow beam with small angular divergence is described. It uses both surface ionization and surface neutralization in conjunction with electric fields to selectively emit a highly directional (orthotropic) beam of neutral atoms. The source can be modulated electronically and lends itself to scanning. This orthotropic source is ideal for the efficient use of rare atomic species, is well suited for atomic clocks, is essential for the efficient delivery of radioactive atoms to optical traps, and has the potential to produce ultrahigh intensity beams of stable atoms. (C) 1996 American Institute of Physics. RP Dinneen, T (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,MAIL STOP 71-259,BERKELEY,CA 94720, USA. NR 23 TC 13 Z9 13 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 752 EP 755 DI 10.1063/1.1146804 PN 1 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA057 UT WOS:A1996UA05700024 ER PT J AU Crow, JT AF Crow, JT TI Method for producing highly uniform field characteristic with line currents SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Symmetries in basic equations for dipole fields of line currents allow the use of a relatively small number of conductors to produce highly uniform transverse (dipole) magnetic fields over a large fraction of the interior of the cylinder on which the wins are located. For example, a simple 12-wire array has better than 1 ppm field uniformity for radii up to 1/3 of the cylinder radius? and better than 0.1% uniformity over more than 1/3 of the cylinder area, and a 50-wire array would have approximately 0.001 ppm uniformity over half the cylinder area if sufficient construction accuracy could be maintained. The configurations are simply transformed to quadrupoles, sextupoles, and higher multipoles that have highly uniform appropriate radial field derivatives. Shielded systems are also described. (C) 1996 American Institute of Physics. RP Crow, JT (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 761 EP 768 DI 10.1063/1.1146806 PN 1 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA057 UT WOS:A1996UA05700026 ER PT J AU Kalantar, DH Barbee, TW DaSilva, LB Glendinning, SG Weber, F Weber, SV Key, MH Knauer, JP AF Kalantar, DH Barbee, TW DaSilva, LB Glendinning, SG Weber, F Weber, SV Key, MH Knauer, JP TI X-ray laser radiography of perturbations due to imprint of laser speckle in 0.35 mu m laser irradiation of a thin Si foil SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID POWER AB A gain saturated yttrium x-ray laser operating at a wavelength of 15.5 nm has been used as an extreme ultraviolet probe to measure optical depth modulations in a thin Si foil by face-on radiography. The high brightness of this Ne-like x-ray laser allows probing of a sample with a high opacity. This technique is sensitive to very small modulations in the optical depth of the foil, corresponding to thickness variations of a few 10 nm of cold material. This technique is used to measure the effect of direct drive laser imprint on a thin Si foil by face-on radiography using multilayer optics to image the foil with 26x magnification. We have recorded modulations in a thin Si foil that was irradiated by a 400 ps, 0.35 mu m beam at an intensity of about 3x10(12) W/cm(2). (C) 1996 American Institute of Physics. C1 RUTHERFORD APPLETON LAB,DIDCOT,OXON,ENGLAND. UNIV ROCHESTER,LASER ENERGET LAB,ROCHESTER,NY. RP Kalantar, DH (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 11 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 781 EP 785 DI 10.1063/1.1146809 PN 1 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA057 UT WOS:A1996UA05700029 ER PT J AU Combs, SK Love, TL Jernigan, TC Milora, SL Frattolillo, A Migliori, S AF Combs, SK Love, TL Jernigan, TC Milora, SL Frattolillo, A Migliori, S TI Acceleration of neon pellets to high speeds for fusion applications SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID JOINT EUROPEAN TORUS; INJECTOR AB The injection of impurity pellets into the plasmas of tokamak fusion reactors has been proposed as a technique to lessen the deleterious effects of plasma disruptions. Equipment and techniques that were previously developed for pneumatic hydrogen pellet injection systems and used for plasma fueling applications were employed for a limited experimental study with neon pellets. Isotopic hydrogen pellets doped with neon have previously been used for injection into fusion plasmas to study impurity particle transport, and pure neon pellets are applicable for disruption studies. Using a repeating pneumatic injector in the laboratory, it was found that the formation and acceleration of 2.7-mm-diam neon pellets were relatively straightforward; reliable operation was demonstrated with both a single- and a two-stage light gas gun, including velocities of similar to 700 m/s with a single-stage injector and up to 1740 m/s with a two-stage injector. Based on the operating sequences and successful tests demonstrated in the laboratory experiments, a three-barrel repeating pneumatic injector installed on the DIII-D tokamak was equipped with the necessary components for neon operation and has been used in initial disruption experiments with 1.8-mm-diam neon pellets. (C) 1996 American Institute of Physics. C1 ENEA,CTR RIC ENERGIA FRASCATI,FRASCATI,ROME,ITALY. RP Combs, SK (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 837 EP 839 DI 10.1063/1.1146819 PN 1 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA057 UT WOS:A1996UA05700039 ER PT J AU Beebe, E Alessi, J Hershcovitch, A Kponou, A Prelec, K Schmieder, RW AF Beebe, E Alessi, J Hershcovitch, A Kponou, A Prelec, K Schmieder, RW TI Development of an electron-beam ion source for a relativistic heavy-ion collider preinjector SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB At Brookhaven National Laboratory (BNL), an electron-beam ion source (EBIS) is operational as a test bed for development of a high current EBIS for relativistic heavy-ion collider (RHIC). Previously, the goal of most EBIS research has been to produce bare or nearly bare nuclei. At BNL, the EBIS is required to produce only medium charge states of heavy ions, e.g., Au35+, since there is further stripping at higher energies. The BNL effort is directed at reaching intensities of interest to RHIC, approximately 3X10(9) particles/pulse, which will require an EBIS electron beam on the order of 10 A. Initial tests using a 1 mm LaB6 cathode have produced electron beam currents up to the design value of 110 mA. A 2 mm LaB6 cathode has been installed and in a first run has produced currents up to 350 mA. This source has so far produced charge states up to Ar16+ using neutral gas injection, and up to Tl50+ using external ion injection. Results of these studies and ion injection trials are presented. (C) 1996 American Institute of Physics. C1 SANDIA NATL LABS,LIVERMORE,CA 94551. RP Beebe, E (reprint author), BROOKHAVEN NATL LAB,AGS DEPT,UPTON,NY 11973, USA. NR 12 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 878 EP 880 DI 10.1063/1.1146827 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000004 ER PT J AU Pardo, RC Harkewicz, R Billquist, PJ AF Pardo, RC Harkewicz, R Billquist, PJ TI Time evolution of charge states in an electron cyclotron resonance ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. NR 0 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 881 EP 881 DI 10.1063/1.1147232 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000005 ER PT J AU Xie, ZQ Lyneis, CM AF Xie, ZQ Lyneis, CM TI Production of high charge state ions with the Advanced Electron Cyclotron Resonance ion source at LBNL SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB Production of high charge state ions with the Advanced Electron Cyclotron Resonance ion source (AECR) at Lawrence Berkeley National Laboratory (LBNL) has been significantly improved by application of various new techniques. Heating the plasma simultaneously with microwaves of two frequencies (10 and 14 GHz) has increased the production of very high charge state heavy ions. The two-frequency technique provides extra electron cyclotron resonance heating zone as compared to the single-frequency heating and improves the heating of the plasma electrons. Aluminum oxide on the plasma chamber surface improves the production of cold electrons at the chamber surfaces and increases the performance of the AECR. Fully stripped argon ions, greater than or equal to 5 enA, were produced and directly identified by the source charge state analyzing system. High charge state ion beams of bismuth and uranium, such as Bi-209(51+) and U-238(53+), were produced by the source and accelerated by the 88-in. cyclotron to energies above 6 MeV/nucleon for the first time. (C) 1996 American Institute of Physics. RP Xie, ZQ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV NUCL SCI,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 13 TC 15 Z9 15 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 886 EP 888 DI 10.1063/1.1146829 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000008 ER PT J AU Anders, A Newman, N Rubin, M Dickinson, M Jones, E Phatak, P Gassmann, A AF Anders, A Newman, N Rubin, M Dickinson, M Jones, E Phatak, P Gassmann, A TI Hollow-anode plasma source for molecular beam epitaxy of gallium nitride SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID THIN-FILMS; GROWTH; GAN; DISCHARGE AB GaN films have been grown by molecular beam epitaxy (MBE) using a hollow-anode nitrogen plasma source. The source was developed to minimize defect formation as a result of contamination and ion damage. The hollow-anode discharge is a special form of glow discharge with very small anode area. A positive anode voltage drop of 30-40 V and an increased anode sheath thickness leads to ignition of a relatively dense plasma in front of the anode hole. Driven by the pressure gradient, the ''anode'' plasma forms a bright plasma jet streaming with supersonic velocity towards the substrate. Films of GaN have been grown on (0001) SiC and (0001) Al2O3 at 600-800 degrees C. The films were investigated by photoluminescence, cathodoluminescence, x-ray diffraction, Rutherford backscattering, and particle-induced x-ray emission. The film with the highest structural quality had a rocking curve width of 5 arcmin, the lowest reported value for MBE growth to date. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP Anders, A (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Newman, Nathan/E-1466-2011; Anders, Andre/B-8580-2009 OI Newman, Nathan/0000-0003-2819-9616; Anders, Andre/0000-0002-5313-6505 NR 14 TC 27 Z9 27 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 905 EP 907 DI 10.1063/1.1146834 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000013 ER PT J AU Nolen, JA AF Nolen, JA TI Review of work related to ion sources and targets for radioactive beams at Argonne SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID ISOLDE AB A group including many ANL Physics Division staff and ATLAS outside users has discussed possibilities for research with radioactive ion beams and prepared a working paper entitled ''Concept for an Advanced Exotic Beam Facility Based on ATLAS.'' Several subgroups have been working on issues related to ion sources and targets which could be used in the production and ionization of radionuclides with high power primary beams. Present activities include: (a) setting up an ion source test stand to measure emittances and energy spreads of ISOL-type ion sources, (b) experiments to evaluate methods of containing liquid uranium for production targets, (c) experimental evaluation of geometries for the generation of secondary neutron beams for production of radionuclides, (d) setting up an ISOL-type ion source at a neutron generator facility to measure fission fragment release times and efficiencies, and (e) computer simulations of an electron-beam charge-state amplifier to increase the charge states of 1(+) secondary beams to 2, 3, or 4(+). The present status of these projects and future plans are presented in this report. (C) 1996 American Institute of Physics. RP Nolen, JA (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 24 TC 2 Z9 2 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 935 EP 937 DI 10.1063/1.1146777 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000024 ER PT J AU Marrs, RE AF Marrs, RE TI Production of U92+ with an electron beam ion trap SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID CROSS-SECTIONS AB A super electron beam ion trap has been used to produce bare U92+ ions at an electron beam energy of 198 keV. Evaporative cooling with light ions was used to trap a population of 5X10(4) highly charged uranium ions for many seconds and reduce their temperature to less than 2q eV, suggesting that a very low emittance source of these ions is possible. Roughly 10 U92+ and 500 U91+ ions were present in the Super electron beam ion trap as determined from x-ray emission spectra of the trapped ions. (C) 1996 American Institute of Physics. RP Marrs, RE (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 18 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 941 EP 944 DI 10.1063/1.1146646 PN 2 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000026 ER PT J AU Brown, IG Anders, A Anders, S Dickinson, MR MacGill, RA AF Brown, IG Anders, A Anders, S Dickinson, MR MacGill, RA TI Peristaltic ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB Conventional ion sources generate energetic ion beams by accelerating the plasma-produced ions through a voltage drop at the extractor, and since it is usual that the ion beam is to propagate in a space which is at ground potential, the plasma source is biased at extractor voltage. For high ion beam energy the plasma source and electrical systems need to be raised to high voltage, a task that adds considerable complexity and expense to the total ion source system. We have developed a system which though forming energetic ion beams at ground potential as usual, operates with the plasma source and electronics at ground potential also. Plasma produced by a nearby source streams into a gridded chamber that is repetitively pulsed from ground to high positive potential, sequentially accepting plasma into its interior region and ejecting it energetically We call the device a peristaltic ion source. In preliminary tests we've produced nitrogen and titanium ion beams at energies from 1 to 40 keV. Here we describe the philosophy behind the approach, the test embodiment that we have made, and some preliminary results. (C) 1996 American Institute of Physics. RP Brown, IG (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Anders, Andre/B-8580-2009; Raoux, Simone/G-3920-2016 OI Anders, Andre/0000-0002-5313-6505; NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 956 EP 958 DI 10.1063/1.1146782 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000030 ER PT J AU Oks, EM Brown, IG Dickinson, MR MacGill, RA AF Oks, EM Brown, IG Dickinson, MR MacGill, RA TI Upgrade of a vacuum arc ion source using a strong pulsed magnetic field SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB A pulsed magnetic field of up to 10 kG was incorporated into a vacuum are ion source. The field was established by a small coil surrounding the are discharge region, powered by either an additional power supply (capacitor bank) or by the are power supply (are current and coil current in series). This addition has led to a number of improvements in source performance: The mean charge state of the metal ions produced was enhanced by a factor of up to 2, for 30 different cathode materials from carbon to bismuth; hybrid metal/gaseous ion beams could be generated when an additional gas (nitrogen, oxygen, or argon) was admitted into the source, with gaseous ion fraction as high as 50%; triggering of the source could be done by a very long lifetime gaseous predischarge technique. We also report on the use of a wire mesh to stabilize the plasma emission surface at the extractor as a means for achieving a flat beam current characteristic as a function of extraction voltage. (C) 1996 American Institute of Physics. C1 STATE ACAD CONTROL SYST & RADIOELECTR,TOMSK 634050,RUSSIA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Oks, EM (reprint author), RUSSIAN ACAD SCI,INST HIGH CURRENT ELECTR,TOMSK 634050,RUSSIA. RI Oks, Efim/A-9409-2014 OI Oks, Efim/0000-0002-9323-0686 NR 14 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 959 EP 961 DI 10.1063/1.1146783 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000031 ER PT J AU Stevens, RR York, RL Geisik, C Swenson, DR AF Stevens, RR York, RL Geisik, C Swenson, DR TI Development of a toroidal-filter H- ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB High brightness H- ion beams will be required for the next generation of accelerator-driven, neutron spallation sources. Volume H- ion sources have the potential for providing these beams at a high duty factor with moderate beam currents and with the long-term operational stability and reliability needed. We report on the results of a continuing study of the Los Alamos National Laboratory version of a toroidal-filter, volume H- ion source which was designed to provide such beams. The H- beam cut-rent, emittance, and electron loading have been measured with the source equipped with a 3- and a 10-mm-diam emission aperture and with several configurations of the plasma filter. The results are compared to beam simulations. (C) 1996 American Institute of Physics. RP Stevens, RR (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 5 TC 0 Z9 0 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1042 EP 1044 DI 10.1063/1.1146752 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000061 ER PT J AU Perkins, LT DeVries, GJ Herz, PR Kunkel, WB Leung, KN Pickard, DS Wengrow, A Williams, MD AF Perkins, LT DeVries, GJ Herz, PR Kunkel, WB Leung, KN Pickard, DS Wengrow, A Williams, MD TI Performance characterization of rf-driven multicusp ion sources SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB Radio-frequency (rf)-driven multicusp ion sources have been developed extensively at Lawrence Berkeley National Laboratory (LBNL) for many applications, each requiring specific source designs. These uses have ranged from large ion sources for neutral-beam injectors-several tens of centimeters in size-to small sources for oil-well logging neutron tubes-a few centimeters in diameter. The advantages associated with internal antenna, rf-driven ion sources include reliability, long component life, ease of operation, and the ability to generate plasmas free of the impurities commonly found in hot-filament discharge sources. We have investigated and characterized the performance of rf-driven sources with respect to the rf operating frequency and ion source size for hydrogen ion species and current density. Furthermore, we have included in this study the aspects of proper coupling of the rf generator to the antenna through an impedance matching network. Finally, critical issues pertaining to general rf operation including beam extraction, rf Shielding, and cooling of transformer cores are discussed. RP Perkins, LT (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720, USA. NR 4 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1057 EP 1059 DI 10.1063/1.1146757 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000066 ER PT J AU Yu, SS Eylon, S Chupp, W Henestroza, E Lidia, S Peters, C Reginato, L Tauschwitz, A Grote, D Deadrick, F AF Yu, SS Eylon, S Chupp, W Henestroza, E Lidia, S Peters, C Reginato, L Tauschwitz, A Grote, D Deadrick, F TI Ion sources for heavy ion fusion SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB The development of ion sources for heavy ion fusion will be reported with particular emphasis on a recently built 2 MV injector. The new injector is based on an electrostatic quadrupole configuration, and has produced pulsed K+ ions of 950 mA peak from a 6.7 in, curved alumino silicate source. The ion beam has reached 2.3 MV with an energy flatness of +/-0.2% over 1 mu s. The measured normalized edge emittance of less than 1 pi mm mrad is close to the source temperature limit. The design, construction, performance, and comparisons with three-dimensional particle-in-cell simulations will be described. (C) 1996 American Institute of Physics. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP Yu, SS (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1098 EP 1101 DI 10.1063/1.1146767 PN 2 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000080 ER PT J AU Pardo, RC Harkewicz, R Billquist, PJ Lyneis, CM Xie, ZQ AF Pardo, RC Harkewicz, R Billquist, PJ Lyneis, CM Xie, ZQ TI Design parameters, goals, and status of the new ATLAS ECR ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB A new 14 GHz ECR ion source for the ATLAS facility is under construction. The new source is an evolution of the 14 GHz AECR Lawrence Berkeley source. The new source will feature an all-aluminum hexapole main chamber and enhanced peak radial and solenoid magnetic fields compared to the existing AECR. Most of the other design features of the existing source are maintained in this design. The new source will be mounted on a new 300 kV high-voltage platform in order to match the velocity requirements of the existing PII injector linac. Achieving the very precise goal of a few electrical microamps of U-238(+33) from this source Will allow the ATLAS facility to provide Coulomb-barrier energies of uranium without the use of an additional stripper foil and will significantly enhance the capabilities of ATLAS for the heaviest of beams. The project status and more details of the source system design are discussed. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Pardo, RC (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1180 EP 1182 DI 10.1063/1.1146725 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000101 ER PT J AU Alton, GD Mills, GD AF Alton, GD Mills, GD TI A high-efficiency positive (negative) surface ionization source for radioactive ion beam SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0034-6748 EI 1089-7623 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1189 EP 1189 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000105 ER PT J AU Alton, GD Williams, C AF Alton, GD Williams, C TI A combined thermal dissociation and electron impact ionization source for radioactive ion beam generation SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB, OAK RIDGE, TN 37831 USA. RI J, H/C-1544-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0034-6748 EI 1089-7623 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1189 EP 1189 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000104 ER PT J AU Anders, A Brown, I MacGill, R Dickinson, M AF Anders, A Brown, I MacGill, R Dickinson, M TI High ion charge states in a high-current, short-pulse, vacuum arc ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID CATHODIC PLASMA-JET AB Ions of the cathode material are formed at vacuum are cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only a little on the discharge current as long as the current is low. Here we report on experiments with short pulses (several mu s) and high currents (several kA); this regime of operation is thus approaching a more vacuum sparklike regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution. (C) 1996 American Institute of Physics. RP Anders, A (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720, USA. NR 23 TC 26 Z9 26 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1202 EP 1204 DI 10.1063/1.1146731 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000110 ER PT J AU MacGill, RA Dickinson, MR Brown, IG AF MacGill, RA Dickinson, MR Brown, IG TI Vacuum arc ion sources - Micro to macro SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID BROAD-BEAM AB Vacuum are ion sources provide a convenient tool for the production of intense beams of metal ions. The sources are relatively easy to construct and they can produce beams from all of the solid metals as well as from compounds, alloys, and mixtures. We have made a number of different kinds of such sources over the course of our development work at LBL in the past decade, from very small ''thumb-size'' versions to a very large one with a 50 cm diameter extractor. Beam current ranges from a few milliamperes up to almost 10 A and extraction voltage from about 1 to 100 kV. Multicathode versions have been made so that one can switch between metal ion species simply and quickly. Most of the sources have been operated in a repetitively pulsed mode, and we've also tested a de version. Here we outline some construction features of the array of vacuum are ion sources that we've developed and used, and describe their performance and limitations. (C) 1996 American Institute of Physics. RP MacGill, RA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 8 TC 1 Z9 1 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1210 EP 1212 DI 10.1063/1.1146734 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000113 ER PT J AU Welton, RF Moran, TF Feeney, RK Thomas, EW AF Welton, RF Moran, TF Feeney, RK Thomas, EW TI A simple electron cyclotron resonance ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 GEORGIA INST TECHNOL,SCH CHEM,ATLANTA,GA 30332. GEORGIA INST TECHNOL,SCH ELECT ENGN,ATLANTA,GA 30332. GEORGIA INST TECHNOL,SCH PHYS,ATLANTA,GA 30332. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1216 EP 1216 DI 10.1063/1.1147237 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000115 ER PT J AU Steski, DB Zarcone, MJ Smith, KS Thieberger, P AF Steski, DB Zarcone, MJ Smith, KS Thieberger, P TI Neutralization of space charge forces using ionized background gas SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB The Tandem Van de Graaff at Brookhaven National Laboratory has delivered pulsed gold beam to the Alternating Gradient Synchrotron (AGS) and AGS Booster since 1992 for relativistic heavy ion physics. There is an ongoing effort to improve the quality and intensity of the negative ion beam delivered to the Tandem from the present Cs sputter sources. Because the beam energy is low (approximately 30 keV) and the current high, there are significant losses due to space charge forces. One of the ways being explored to overcome these losses is to neutralize the space charge forces with ionized background gas. On an ion source test bench, using three different gases (Ar, N-2, and Xe), the percentage of current transported from the source to a downstream Faraday cup was increased from 10% to 40% by bleeding in gas. Bleeding in Xe resulted in the best transmission. The time dependence of the neutralization as a function of gas pressure was also observed. This system is presently being transferred to the Negative Ion Injector of the Tandem for use in upcoming heavy ion experiments. (C) 1996 American Institute of Physics. RP Steski, DB (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 2 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1221 EP 1223 DI 10.1063/1.1146738 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000119 ER PT J AU Spence, D McMichael, G Lykke, KR Schneider, JD Sherman, J Stevens, R Hodgkins, D AF Spence, D McMichael, G Lykke, KR Schneider, JD Sherman, J Stevens, R Hodgkins, D TI Production of high-brightness continuous wave proton beams with very high proton fractions SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. LOS ALAMOS NATL LAB,ACCELERATOR OPERAT & TECHNOL DIV,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1239 EP 1239 DI 10.1063/1.1147239 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000125 ER PT J AU Sarstedt, M Lee, Y Leung, KN Perkins, LT Pickard, DS Weber, M Williams, MD AF Sarstedt, M Lee, Y Leung, KN Perkins, LT Pickard, DS Weber, M Williams, MD TI Beam emittance measurements on multicusp ion sources SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source is planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 mu m patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a de filament-discharge plasma has also been compared to that of a rf-generated plasma. (C) 1996 American Institute of Physics. RP Sarstedt, M (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720, USA. NR 5 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1249 EP 1251 DI 10.1063/1.1146688 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000129 ER PT J AU Sarstedt, M AF Sarstedt, M TI Sectional and projectional emittance measurements SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1271 EP 1271 DI 10.1063/1.1147241 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000138 ER PT J AU Sherman, J Bolme, G Geisik, C Gilpatrick, D Hansborough, L Hodgkins, D Lara, P Meyer, E Power, J Rose, C Sandoval, D Schafstall, P Schneider, JD Stettler, M Stevens, R Thuot, M Wright, R Zaugg, T Spence, D McMichael, G Taylor, T AF Sherman, J Bolme, G Geisik, C Gilpatrick, D Hansborough, L Hodgkins, D Lara, P Meyer, E Power, J Rose, C Sandoval, D Schafstall, P Schneider, JD Stettler, M Stevens, R Thuot, M Wright, R Zaugg, T Spence, D McMichael, G Taylor, T TI Microwave proton source development for a high-current linac injector (invited) SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID ION; HYDROGEN AB Powerful cw proton linear accelerators (100 mA at 0.5-1.0 GeV) are being proposed for spallation neutron-source applications. A 75-keV, 110-mA de proton injector using a microwave ion source is being tested for these applications. It has achieved 80-keV, 110-mA hydrogen-ion-beam operation. Video and de beam-current toroid diagnostics are operational, and an EPICS control system is also operational on the 75-keV injector. A technical base development program has also been carried out on a 50-keV injector obtained from Chalk River Laboratories, and it includes low-energy beam transport studies, ion source lifetime tests, and proton-fraction enhancement studies. Technical base results and the present status of the 75-keV injector will be presented. (C) 1996 American Institute of Physics. C1 ARGONNE NATL LAB,TECHNOL DEV DIV,ARGONNE,IL 60439. AECL,CHALK RIVER LABS,CHALK RIVER,ON K0J 1J0,CANADA. RP Sherman, J (reprint author), LOS ALAMOS NATL LAB,ACCELERATOR OPERAT & TECHNOL DIV,POB 1663,LOS ALAMOS,NM 87545, USA. NR 34 TC 6 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1296 EP 1301 DI 10.1063/1.1146701 PN 2 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000146 ER PT J AU Leung, KN AF Leung, KN TI Radio frequency multicusp ion source development SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US ID RF AB The radio-frequency (rf) driven multicusp source was originally developed for use in the Superconducting Super Collider injector. It has been demonstrated that the source can meet the H- beam current and emittance requirements for this application. By employing a porcelain-coated antenna, a clean plasma discharge with very long-life operation can be achieved. Today, the rF source is used to generate both positive and negative hydrogen ion beams and has been tested in various particle accelerator laboratories throughout the world. Applications of this ion source have been extended to other fields such as ion beam lithography, oil-well logging, ion implantation, accelerator mass spectrometry and medical therapy machines. This paper summarizes the latest rf ion source technology and development at the Lawrence Berkeley National Laboratory. (C) 1996 American Institute of Physics. RP Leung, KN (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 14 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1302 EP 1307 DI 10.1063/1.1146702 PN 2 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000147 ER PT J AU Alonso, JR AF Alonso, JR TI High-current negative-ion sources for pulsed spallation neutron sources: LBNL Workshop, October 1994 SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB The neutron scattering community has endorsed the need for a high-power (1-5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (submicrosecond) bursts of-cold neutrons, said time structure offering advantages over the continuous flux from a reactor. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 kW source in the UK), and call for a high-current (similar to 100 mA peak) H- source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The 1-5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. The Workshop reported on here, held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H- source technologies, and identified necessary R&D efforts to bridge the gap. (C) 1996 American Institute of Physics. RP Alonso, JR (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 10 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1308 EP 1313 DI 10.1063/1.1146703 PN 2 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000148 ER PT J AU Burns, EJT Brainard, JP Draper, CH Ney, RH Leung, KN Perkins, LT Williams, MD Wilde, SB AF Burns, EJT Brainard, JP Draper, CH Ney, RH Leung, KN Perkins, LT Williams, MD Wilde, SB TI Solenoidal and monocusp ion source (SAMIS) SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1317 EP 1317 DI 10.1063/1.1147242 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000150 ER PT J AU Saadatmand, K Arbique, G Hebert, J Valicenti, R Leung, KN AF Saadatmand, K Arbique, G Hebert, J Valicenti, R Leung, KN TI Performance of a high current H- radio frequency volume ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB To evaluate the performance of a high current H- rf-driven volume ion source, the Superconducting Super Collider ion source was modified to accommodate a set of cesium dispensers so that a trace amount of cesium could be introduced into the plasma grid collar. A plasma grid heater element controls the temperature of the cesiated surfaces and the rate of cesium dispensation. With this modification, beam currents in excess of 100 mA and electron to H- current ratios close to one have been observed. In contrast, the uncesiated source provided 30 mA of H- beam with an e/H- ratio >25. In both cases the source was operated with a 100 mu s beam pulse width at a 10 Hz repetition rate, and an extraction voltage of 35 kV. This cesium enhanced source is a strong candidate for use in high current H- accelerators. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP Saadatmand, K (reprint author), SUPERCONDUCTING SUPER COLLIDER LAB,2550 BECKLEYMEADE AVE,DALLAS,TX 75237, USA. NR 3 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1318 EP 1320 DI 10.1063/1.1146705 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000152 ER PT J AU Pickard, DS Kunkel, WB Leung, KN Young, AT AF Pickard, DS Kunkel, WB Leung, KN Young, AT TI Plasma production via laser-induced photoemission SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1340 EP 1340 DI 10.1063/1.1147244 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000160 ER PT J AU Welton, RF Piotrowski, A Alton, GD Murray, SN AF Welton, RF Piotrowski, A Alton, GD Murray, SN TI Effusive flow delay times for gaseous species in a compact rf ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1353 EP 1353 DI 10.1063/1.1147245 PN 2 PG 1 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000165 ER PT J AU Williams, MD deVries, GJ Gough, RA Leung, KN Monroy, M AF Williams, MD deVries, GJ Gough, RA Leung, KN Monroy, M TI Production of multiply charge-state ions in a multicusp ion source SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article; Proceedings Paper CT 6th International Conference on Ion Sources CY SEP 10-16, 1995 CL WHISTLER, CANADA SP TRIUMF, Canada, Northrop Grumman, US, Walker Sci Inc, US, Edwards High Vacuum, US AB High charge state ion beams are commonly used in atomic and nuclear physics experiments. Multiply charged ions are normally produced in an ECR or in an EBIS. Multicusp generators can confine primary electrons very efficiently. Therefore, the electrical and gas efficiencies of these devices are high. Since the magnetic cusp fields are localized near the chamber wall, large volumes of uniform and high density plasmas can be obtained at low pressure, conditions favorable for the formation of multiply charged state ions. Attempts have been made at LBNL to generate multiply charged ion beams by employing a 25-cm diam by 25-cm long multicusp source. Experimental results demonstrated that charge states as high as 7+ can be obtained with argon or xenon plasmas. Multiply charged metallic ions such as tungsten and titanium have also been successfully formed in the multicusp source by evaporation and sputtering processes. In order to extend the charge state to higher values, a novel technique of injecting high energy electrons into the source plasma is proposed. If this is successful, the multicusp source will become very useful for radioactive beam accelerators, ion implantation, and nuclear physics applications. (C) 1996 American Institute of Physics. RP Williams, MD (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720, USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAR PY 1996 VL 67 IS 3 BP 1384 EP 1386 DI 10.1063/1.1146676 PN 2 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA UA060 UT WOS:A1996UA06000179 ER PT J AU Doughty, DH AF Doughty, DH TI Materials issues in lithium ion rechargeable battery technology SO SAMPE JOURNAL LA English DT Article AB Lithium ion rechargeable batteries are predicted to replace Ni/Cd as the workhorse consumer battery. The pace of development of this battery system is determined in large part by the availability of materials and the understanding of interfacial reactions between materials. Lithium ion technology is based on the use of two lithium intercalating electrodes. Carbon is the most commonly used anode material, while the cathode materials of choice have been layered lithium metal chalcogenides (LiMX(2)) and lithium spinel-type compounds. Electrolytes may be either organic liquids or polymers. Although the first practical use of graphite intercalation compounds as battery anodes was reported in 1981 for molten salt cells and, in 1983, for ambient temperature systems, it was not until Sony Energytech announced a new lithium ion intercalating carbon anode in 1990, that interest peaked. The reason for this heightened interest is that these electrochemical cells have the high energy density, high voltage, and light weight of metallic lithium, but without the disadvantages of dendrite formation on charge, improving their safety and cycle life. This publication will review recent developments in the field and materials needs that will enhance future prospects for this important electrochemical system. RP Doughty, DH (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 26 TC 12 Z9 13 U1 2 U2 15 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 SN 0091-1062 J9 SAMPE J JI Sampe J. PD MAR-APR PY 1996 VL 32 IS 2 BP 75 EP 81 PG 7 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA TX478 UT WOS:A1996TX47800017 ER PT J AU Almgren, AS Bell, JB Szymczak, WG AF Almgren, AS Bell, JB Szymczak, WG TI A numerical method for the incompressible Navier-Stokes equations based on an approximate projection SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE incompressible flow; projection methods ID MIXING LAYERS AB In this method we present a fractional step discretization of the time-dependent incompressible Navier-Stokes equations. The method is based on a projection formulation in which we first solve diffusion-convection equations to predict intermediate velocities, which are then projected onto the space of divergence-free vector fields. Our treatment of the diffusion-convection step uses a specialized second-order upwind method for differencing the nonlinear convective terms that provides a robust treatment of these terms at a high Reynolds number. in contrast to conventional projection-type discretizations that impose a discrete form of the divergence-free constraint, we only approximately impose the constraint; i.e., the velocity held we compute is not exactly divergence-free. The approximate projection is computed using a conventional discretization of the Laplacian and the resulting linear system is solved using conventional multigrid methods. Numerical examples are presented to validate the second-order convergence of the method for Euler, finite Reynolds number, and Stokes now. A second example illustrating the behavior of the algorithm on an unstable shear layer is also presented. C1 USN,CTR SURFACE WARFARE,SILVER SPRING,MD 20903. RP Almgren, AS (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 20 TC 104 Z9 108 U1 3 U2 12 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAR PY 1996 VL 17 IS 2 BP 358 EP 369 DI 10.1137/S1064827593244213 PG 12 WC Mathematics, Applied SC Mathematics GA TX673 UT WOS:A1996TX67300004 ER PT J AU Treitler, I AF Treitler, I TI Culture and the problem of universal access to electronic information systems SO SOCIAL SCIENCE COMPUTER REVIEW LA English DT Article DE information technology; communication strategies; universal access AB The technical design of information systems tends to drive the information structure and content of the systems and is not driven by the social and cultural needs of end users. The content, structure, and context of end user communication strategies should be a component of systems design for the National Information Infrastructure (NII). Without such integration of the communication strategies of multiple end user groups and communities, universal access to the NII cannot be guaranteed. RP Treitler, I (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 2 TC 3 Z9 3 U1 0 U2 0 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 0894-4393 J9 SOC SCI COMPUT REV JI Soc. Sci. Comput. Rev. PD SPR PY 1996 VL 14 IS 1 BP 62 EP 64 DI 10.1177/089443939601400120 PG 3 WC Computer Science, Interdisciplinary Applications; Information Science & Library Science; Social Sciences, Interdisciplinary SC Computer Science; Information Science & Library Science; Social Sciences - Other Topics GA UJ314 UT WOS:A1996UJ31400020 ER PT J AU Tonn, BE AF Tonn, BE TI Global society and information technology - Social science challenges in the 21st century SO SOCIAL SCIENCE COMPUTER REVIEW LA English DT Article DE information technology quality of life; sustainable development; systems development AB Information technology will greatly influence the quality of life in the 21st century. The challenge is to use the technology to help overcome numerous global, regional, and local problems that threaten the quality of life. These problems include global overpopulation, intense and potentially socioeconomically destructive global economic competition, continued pressures on the global environment, increasing levels of regionalized armed conflicts, regional water shortages and other regional environmental problems, and local transportation congestion, poverty, crime, and drug abuse. Social scientists must become aggressively involved and accept leadership roles in the conceptualization, development, and implementation of computer-based systems that have broad social impact. RP Tonn, BE (reprint author), OAK RIDGE NATL LAB,POLICY ANAL SYST GRP,OAK RIDGE,TN 37831, USA. NR 4 TC 2 Z9 2 U1 2 U2 6 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 0894-4393 J9 SOC SCI COMPUT REV JI Soc. Sci. Comput. Rev. PD SPR PY 1996 VL 14 IS 1 BP 78 EP 80 DI 10.1177/089443939601400124 PG 3 WC Computer Science, Interdisciplinary Applications; Information Science & Library Science; Social Sciences, Interdisciplinary SC Computer Science; Information Science & Library Science; Social Sciences - Other Topics GA UJ314 UT WOS:A1996UJ31400024 ER PT J AU Ellis, H Ringold, PL Holdren, GR AF Ellis, H Ringold, PL Holdren, GR TI Emission reductions and ecological response: Management models for acid rain control SO SOCIO-ECONOMIC PLANNING SCIENCES LA English DT Article ID LINEAR-PROGRAMMING MODEL; LONG-RANGE TRANSPORT; CONTROL STRATEGIES; POLICY ANALYSIS; DEPOSITION; WATER; SELECTION AB Presented in this paper is a series of optimization analyses for acid rain control in eastern North America. The analyses involve models that minimize cost or emissions removed subject to environmental quality restrictions at selected sensitive receptor locations. Site-specific critical loads are the measures of environmental quality, where critical loads are roughly interpreted as levels of areal pollutant deposition beyond which deleterious ecological effects are thought to occur. Our approach is demonstrated with an application that includes critical loads estimated for 768 lakes in the Adirondacks. As well, a stratified random subsample of 122 sites is modeled to assess the effects of sampling intensity on the control scenarios that are identified through the optimization procedures. Two different models for estimating site-specific critical loads are used and their effects on control strategies are assessed. From a somewhat broader perspective, this work is a demonstration of the feasibility and usefulness of large-scale integrated assessment and the role that operations research methods can play in that process. C1 US EPA, NATL HLTH & ENVIRONM EFFECTS LAB, ORD, CORVALLIS, OR 97333 USA. PACIFIC NW LAB, WATER & LAND RESOURCES DEPT, RICHLAND, WA 99352 USA. RP Ellis, H (reprint author), JOHNS HOPKINS UNIV, DEPT GEOG & ENVIRONM ENGN, BALTIMORE, MD 21218 USA. NR 34 TC 2 Z9 2 U1 3 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-0121 J9 SOCIO ECON PLAN SCI JI Socio-Econ. Plan. Sci. PD MAR PY 1996 VL 30 IS 1 BP 15 EP 26 DI 10.1016/0038-0121(95)00025-9 PG 12 WC Economics; Management; Operations Research & Management Science SC Business & Economics; Operations Research & Management Science GA UM542 UT WOS:A1996UM54200002 ER PT J AU Shuai, Z Beljonne, D Bredas, JL Saxena, A Bishop, AR AF Shuai, Z Beljonne, D Bredas, JL Saxena, A Bishop, AR TI Electroabsorption in poly(paraphenylene vinylene) and PtI: Exciton vs band descriptions SO SOLID STATE COMMUNICATIONS LA English DT Article DE organic crystals; optical properties ID NONLINEAR-OPTICAL-PROPERTIES; LIGHT-EMITTING-DIODES; BRIDGED MIXED-VALENCE; CONJUGATED POLYMERS; ELECTRONIC EXCITATIONS; 3RD-HARMONIC GENERATION; 2-PHOTON ABSORPTION; COMPLEXES; POLYENES; SPECTRA AB We contrast the electroabsorption (EA) spectra calculated within an exciton model (Pariser-Parr-Pople Hamiltonian) with that in a band description. The former model combined with small lattice relaxation of excited states is found to give a very good EA description for poly(paraphenylene vinylene) (PPV). A band picture gives qualitatively different EA behavior. As an illustration, we consider a two-band charge-density-wave model, for which we find three kinds of linewidth broadening behavior: (1) For weak fields, the broadening decreases with electric field; (2) for intermediate field strength, the broadening is dominated by damping effects and is independent of the field; (3) for strong fields the traditional Franz-Keldysh law holds. The EA spectrum calculated using the two-band model is in very good agreement with experiments on PtI, a halogen-bridged mixed-valence metal linear-chain complex. C1 LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. RP UNIV MONS, SERV CHIM MAT NOUVEAUX, CTR RECH ELECTRON & PHOTON MOLEC, B-7000 MONS, BELGIUM. RI Bredas, Jean-Luc/A-3431-2008; Shuai, Zhigang/H-5576-2011 OI Bredas, Jean-Luc/0000-0001-7278-4471; Shuai, Zhigang/0000-0003-3867-2331 NR 42 TC 4 Z9 4 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1098 EI 1879-2766 J9 SOLID STATE COMMUN JI Solid State Commun. PD MAR PY 1996 VL 97 IS 12 BP 1063 EP 1067 DI 10.1016/0038-1098(95)00796-2 PG 5 WC Physics, Condensed Matter SC Physics GA TX862 UT WOS:A1996TX86200013 ER PT J AU Hein, EW Andelt, WF AF Hein, EW Andelt, WF TI Coyote visitations to experimentally-placed deer carrion SO SOUTHWESTERN NATURALIST LA English DT Article ID CAPTURING COYOTES; FOOTHOLD TRAPS; SIZE AB Because coyotes (Canis latrans) have been reported to be more vulnerable to capture and to engage in more investigative behavior in low-use areas of their home range, we monitored eight radio-collared coyotes on the Rocky Mountain Arsenal, Adams Co., Colorado to determine if a large clumped food resource, deer (Odocoileus spp.) carrion, increased coyote visitations to low-use areas within their home ranges. We used a vehicle-mounted null-peak antenna system (VMA) and a remote radio telemetry receiver with an attached data logger computer (DL) to monitor coyotes around five carcass sites. Coyote visitations to VMA carcass sites varied among pre-treatment, treatment, and post-treatment periods, but the number of 24-h periods that coyotes visited DL sires did not differ among periods when carcasses were present or absent. Deer carrion was effective in attracting and keeping coyotes in less familiar areas of their home ranges; seven of eight (88%) coyotes visited deer carrion for average durations of 110 min at VMA sites and 115 min at DL sites. No coyotes visited carcasses outside of their home ranges. Because coyotes visited carcass sites in unfamiliar areas of their home ranges for extended time periods, carrion may enhance visitations to scent stations, capture, and delivery of baits to coyotes. C1 COLORADO STATE UNIV,DEPT FISHERY & WILDLIFE BIOL,FT COLLINS,CO 80523. LOS ALAMOS NATL LAB,ENVIRONM SCI GRP,LOS ALAMOS,NM 87545. NR 33 TC 4 Z9 4 U1 0 U2 4 PU SOUTHWESTERN ASSN NATURALISTS PI SAN MARCOS PA SOUTHWEST TEXAS STATE UNIV, DEPT BIOLOGY, 601 UNIVERSITY DR, SAN MARCOS, TX 78666 SN 0038-4909 J9 SOUTHWEST NAT JI Southw. Natural. PD MAR PY 1996 VL 41 IS 1 BP 48 EP 53 PG 6 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA VJ857 UT WOS:A1996VJ85700005 ER PT J AU Ferraro, JR AF Ferraro, JR TI A history of Raman spectroscopy SO SPECTROSCOPY LA English DT Article ID DIODE-LASER; ARRAY DETECTOR; SPECTROMETER; EXCITATION; MICROSCOPY C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NR 61 TC 5 Z9 5 U1 3 U2 8 PU ADVANSTAR COMMUNICATIONS PI DULUTH PA 131 W FIRST ST, DULUTH, MN 55802 SN 0887-6703 J9 SPECTROSCOPY JI Spectroscopy PD MAR-APR PY 1996 VL 11 IS 3 BP 18 EP & PG 7 WC Spectroscopy SC Spectroscopy GA VJ162 UT WOS:A1996VJ16200002 ER PT J AU Lelovic, M Krishnaraj, P Eror, NG Iyer, AN Balachandran, U AF Lelovic, M Krishnaraj, P Eror, NG Iyer, AN Balachandran, U TI Transport critical current density above 10(5) A cm(-2) at 77 K in Bi1.8Pb0.4Sr2.0Ca2.2Cu3.0Oy superconducting tapes made by the Ag wire-in-tube method SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article AB Transport critical current density (J(c)) is a limiting factor in the practical application of (Bi,Pb)(2)Sr2Ca2Cu3Oy (BSCCO-2223) high-temperature superconducting materials. The minimum requirement is for a J(c) of 10(5) A cm(-2) in long wires and tapes, at 77 K and in a high magnetic field. The issue of current distribution inside Ag-sheathed tapes has been resolved by showing that the region of high critical current density is next to the silver. In this paper we report a J, value > 10(5) A cm(-2) at 77 K in a self-field in Bi1.8BPb0.4Sr2.0Ca2.2Cu3.0Oy superconducting tapes made by the Ag wire-in-tube method, in which a silver wire was introduced into the silver tube. The silver wire extended along the entire length of the tape and reduced the difference between the nominal cross section of the superconductor and its actual current-carrying cross section. At 77 K and self-field, a maximum J(c) of 2 x 10(5) A cm(-2) (critical current I-c = 22 A) was measured after three pressing cycles at 800 degrees C in a 7% O-2 atmosphere. The average thickness of the superconducting layer between the sides of silver layers was in the order of 1-2 mu m and the width was 3.6 mm. This study confirms that the current-carrying region in BSCCO tapes is the layer adjacent to the Ag sheath. Previously it was shown that the superconductor core for thicker superconductor layers (similar to 70 mu m) does not carry significant current. C1 UNIV PITTSBURGH,PITTSBURGH,PA 15261. ARGONNE NATL LAB,DIV ENERGY TECHNOL,ARGONNE,IL 60439. NR 14 TC 50 Z9 50 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD MAR PY 1996 VL 9 IS 3 BP 201 EP 204 DI 10.1088/0953-2048/9/3/012 PG 4 WC Physics, Applied; Physics, Condensed Matter SC Physics GA TZ481 UT WOS:A1996TZ48100012 ER PT J AU Hirvonen, JP Koskinen, J Jervis, JR Nastasi, M AF Hirvonen, JP Koskinen, J Jervis, JR Nastasi, M TI Present progress in the development of low friction coatings SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT European-Materials-Research-Society 1995 Spring Conference, Symposium H - Advanced Deposition Processes and Characterization of Protective Coatings CY MAY 22-26, 1995 CL STRASBOURG, FRANCE SP European Mat Res Soc DE coatings; diamond-like; low friction; molybdenum disulphide ID DIAMOND-LIKE CARBON; MOS2 FILMS; THIN-FILMS; ENERGY; SPACE; WEAR AB Low friction coatings are being developed for a variety of reasons. Practical conditions in which machines and machine elements have to operate are ever expanding and more often involve features which preclude liquid or grease lubrication. An example of such conditions very common in everyday life is the food-processing industry, where any kind of lubrication is impossible owing to the risk of contamination of a product. Some other conditions include hostile environments such as high temperature or vacuum. High temperatures are common, for example, in the chemical industry and power generation, whereas vacuum is often associated with space technology. A new motivation for development of low friction coatings is a general trend to reduce lubrication for reasons of environmental compliance. All these together challenge materials technology and surface engineering especially. Accordingly, activity in the area of the development of coating materials, sophisticated deposition methods as well as posttreatments of coatings has been vigorous in recent years. In this paper we first review typical conditions in which low friction coatings are sought as well as the demands for properties which coatings should fulfil in order to function in an appropriate way. This is followed by a more detailed presentation of three different coatings for three different conditions. Amorphous hard carbon films deposited by are discharge deposition are hydrogen free, have high hardness and are best characterized as an amorphous diamond. The films have been shown to possess a friction coefficient below 0.2 or even below 0.1 in dry-sliding conditions associated with good wear resistance. Potential conditions in which these films could be used are dry sliding at room temperature and in a normal atmosphere with adequate humidity. The second coating family which will be presented is based on molybdenum disulphide (MoS2). These are typical coatings for use in a vacuum. Many attempts have been made to overcome the many limitations of these coatings with post-treatments, In this presentation, ion beam and laser processing of MoS2 coatings with or without alloying are dealt with. The third set of conditions includes high temperatures. This is one of the most difficult areas of low friction coatings and no final solutions for practical purposes have been developed. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Hirvonen, JP (reprint author), VTT MFG TECHNOL,SF-02044 VTT,FINLAND. RI Koskinen, Jari/J-3886-2014 NR 41 TC 66 Z9 70 U1 2 U2 21 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD MAR PY 1996 VL 80 IS 1-2 BP 139 EP 150 DI 10.1016/0257-8972(95)02701-7 PG 12 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA UE933 UT WOS:A1996UE93300027 ER PT J AU Gao, Y Liang, Y Chambers, SA AF Gao, Y Liang, Y Chambers, SA TI Synthesis and characterization of Nb-doped TiO2(110) surfaces by molecular beam epitaxy SO SURFACE SCIENCE LA English DT Article DE atomic force microscopy; electron-solid diffraction; molecular beam epitaxy; photoelectron spectroscopy; single crystal epitaxy; titanium oxide ID PHOTOELECTRON DIFFRACTION; TIO2; SPECTROSCOPY; COMPENSATION; NIOBIUM; RUTILE AB Epitaxial films of Nb-doped TiO2 rutile were grown on TiO2(110) rutile at 600 degrees C by molecular beam epitaxy. These films grow in a layer-by-layer fashion for doping levels up to 20 at.%. In addition, reflection high-energy and low-energy electron diffraction, along with X-ray photoelectron diffraction, reveal that the overlayers possess excellent long- and short-range structure order up to 20 at.%. However, strain-induced disorder becomes prevalent for higher doping levels, and the surfaces roughen accordingly. X-ray photoelectron diffraction reveals that Nb atoms substitutionally incorporate at cation sites in the rutile lattice for all doping levels, leading to a mixed rutile NbxTi1-xO2 phase. Analysis of Nb3d and Ti2p core-level binding energies reveal that the oxidation state of both Ti and Nb is 4+. RP Gao, Y (reprint author), PACIFIC NW LAB, POB 999, MS K2-12, RICHLAND, WA 99352 USA. NR 41 TC 54 Z9 54 U1 1 U2 24 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR 1 PY 1996 VL 348 IS 1-2 BP 17 EP 27 DI 10.1016/0039-6028(95)00943-4 PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA TY777 UT WOS:A1996TY77700004 ER PT J AU Knutsen, K Orlando, TM AF Knutsen, K Orlando, TM TI Low-energy (5-80 eV) electron-stimulated desorption of H+(D+), OH+(OD+), O+, and NO+ from solution-grown NaNO3 crystals SO SURFACE SCIENCE LA English DT Article DE alkali metals; electron stimulated desorption (ESD); electron-solid interactions, scattering, diffraction; hydrides; NaNO3; nitrogen oxides; surface defects; water ID 2P CORE EXCITON; PHOTOELECTRON-SPECTROSCOPY; METAL NITRATES; SODIUM-HALIDES; ALKALI; HYDROGEN; DECAY; DECOMPOSITION; TEMPERATURE; RADIOLYSIS AB Low-energy (5-80 eV) electron-stimulated desorption of H+(D+), OH+(OD+), O+, and NO+ from solution-gown NaNO3 crystals is studied by quadrupole and time-of-flight mass spectrometry. Desorption yields and thresholds are reported as a function of incident electron energy and flux. The O+ and NO+ are degradation products of the NaNO, substrate, whereas the H+(D+) and OH+(OD+) ions arise primarily from -H(D) and/or -OH(OD) termination sites. The threshold energies indicate that degradation involves Auger-stimulated dissociation of the nitrate group. We associate the similar to 24 eV threshold for H+(D+) desorption with intramolecular decay of a single hole in the O(2s) level of either Na-OH(OD), or possibly H-NO3, terminal groups and the yield increase at similar to 33 eV with intermolecular decay of the Na (2p-->3s) exciton. We correlate the OH+(OD+), O+ and NO+ desorption thresholds at similar to 33 eV primarily with excitation of the Na (2p-->3s) exciton. Desorption of NO+ and O+ may also involve intramolecular Auger decay of holes in the 2e' and/or 3a(1)' nitrate valence bands. The H+ translational energy distributions peak at similar to 5-7.5 eV, and H+ dominates the cation desorption yields from solution grown NaNO3 crystals by a factor of similar to 100. C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. NR 43 TC 13 Z9 13 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR 1 PY 1996 VL 348 IS 1-2 BP 143 EP 152 DI 10.1016/0039-6028(95)00980-9 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA TY777 UT WOS:A1996TY77700016 ER PT J AU Jenks, CJ Rishi, S Thiel, PA AF Jenks, CJ Rishi, S Thiel, PA TI Effectiveness of a fluorinated nickel surface in catalyzing the decomposition of a perfluoropolyether analog SO SURFACE SCIENCE LA English DT Article DE fluorocarbons; halides; nickel; thermal desorption spectroscopy ID OXIDATIVE-DEGRADATION REACTIONS; RAY PHOTOELECTRON-SPECTROSCOPY; ION MASS-SPECTROMETRY; PERFLUOROPOLYALKYLETHER OIL; PERFLUOROALKYL ETHERS; ULTRAHIGH-VACUUM; METAL-SURFACES; DIETHYL-ETHER; IRON SURFACES; THIN-FILMS AB We describe ultrahigh Vacuum studies of a perfluoropolyether analog, perfluorodiethoxymethane (PFDEM), interacting with a partially fluorinated nickel surface. Results of temperature-programmed desorption studies show that PFDEM does not undergo C-F bond cleavage and subsequent formation of nickel-fluorine bonds. The use of a defect-rich surface has no effect on the results. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. NR 65 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAR 1 PY 1996 VL 348 IS 1-2 BP 175 EP 184 DI 10.1016/0039-6028(95)01046-7 PG 10 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA TY777 UT WOS:A1996TY77700020 ER PT J AU Gifford, AN Gatley, SJ Ashby, CR AF Gifford, AN Gatley, SJ Ashby, CR TI Endogenously released dopamine inhibits the binding of dopaminergic PET and SPECT ligands in superfused rat striatal slices SO SYNAPSE LA English DT Article DE dopamine; PET; striatum; slice; electrical stimulation; binding ID POSITRON EMISSION TOMOGRAPHY; HIGH-AFFINITY; NUCLEUS-ACCUMBENS; INVIVO BINDING; D-AMPHETAMINE; KINETIC-PROPERTIES; ADENYLATE-CYCLASE; N-METHYLSPIPERONE; RECEPTOR-BINDING; I-125 EPIDEPRIDE AB Pharmacologically induced changes in synaptic levels of dopamine (DA) have been found, in some studies, to affect the in vivo binding of dopaminergic radioligands. In the present study we used a superfused brain slice preparation to examine the effect of synaptically released dopamine on the binding of some commonly used PET and SPECT radioligands under more controlled conditions than those present in vivo. The release of DA was evoked by electrical stimulation of striatal slices and the sensitivity of binding of the D-1 receptor ligand, [H-3]SCH 23390, the D-2 receptor ligands [H-3]raclopride and [I-123]epidepride, and the DA uptake transporter ligands, [H-3]WIN 35,428 and [I-123]RTI-55, to the frequency of stimulation examined. Most affected by stimulation was the specific binding of [H-3]SCH 23390, which was fully inhibited at 2.5 Hz. This was followed by [H-3]raclopride and [I-123]epidepride, respectively, the binding of the latter showing only a 50% reduction at the highest frequency of 10 Hz. [H-3]WIN 35,428 and [I-123]RTI-55 binding was unaffected by stimulation. The effects of stimulation on [H-3]raclopride binding were prevented by reserpine pretreatment of the rat, when combined with inclusion of the dopamine synthesis inhibitor, alpha-methyl-p-tyrosine, in the superfusate medium. We conclude that, in-brain slices, the binding of D-1 and D-2 receptor ligands but not that of DA uptake transporter ligands is readily inhibited by DA released into the synaptic cleft. Brain slices may prove to be a useful model system for the investigation of factors affecting competition between radioligand binding and endogenous neurotransmitters. (C) 1996 Wiley-Liss, Inc. RP Gifford, AN (reprint author), BROOKHAVEN NATL LAB,DEPT MED,BLDG 490,UPTON,NY 11973, USA. FU NIMH NIH HHS [R29 MH52155] NR 56 TC 22 Z9 22 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-4476 J9 SYNAPSE JI Synapse PD MAR PY 1996 VL 22 IS 3 BP 232 EP 238 DI 10.1002/(SICI)1098-2396(199603)22:3<232::AID-SYN5>3.0.CO;2-D PG 7 WC Neurosciences SC Neurosciences & Neurology GA TV736 UT WOS:A1996TV73600005 PM 9132991 ER PT J AU Montane, D Jollez, P Salvado, J Farriol, X Chornet, E AF Montane, D Jollez, P Salvado, J Farriol, X Chornet, E TI Rapid soda pulping of wheat straw by the impregnation rapid-steam-pulping process SO TAPPI JOURNAL LA English DT Article DE exploded pulps; explosion pulping; impregnation; mechanical properties; soda pulping; steaming; wheat straw AB Production of chemical pulp from wheat straw was studied at the bench scale using a conventional soda process and a two-stage cooking sequence. The two-stage sequence involves impregnation of the straw with caustic liquor, withdrawal of excess liquor, and rapid (less than or equal to 4 min) steam treatment of the impregnated material at 160-215 degrees C. The impregnation-rapid-steam-pulping (IRSP) sequence for wheat straw shortens the total processing (impregnation + cooking) time to less than 15 min. Strength properties of IRSP pulps are comparable with those of both conventional wheat-straw soda pulps and hardwood kraft pulps when refined to a freeness of 300 mL CSF. C1 UNIV SHERBROOKE,FAC SCI APPL,DEPT GENIE CHIM,SHERBROOKE,PQ J1K 2R1,CANADA. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. RP Montane, D (reprint author), UNIV ROVIRA & VIRGILI,ESCOLA TECN SUPER ENGN,DEPT ENGN QUIM,AUTOVIA DE SALOU S-N,E-43006 TARRAGONA,CATALUNYA,SPAIN. RI Farriol, Xavier/L-9251-2014; Montane, Daniel/K-9172-2014; Salvado, Joan/B-5125-2017 OI Farriol, Xavier/0000-0001-6020-5284; Montane, Daniel/0000-0002-5273-8870; Salvado, Joan/0000-0003-2238-6082 NR 17 TC 13 Z9 13 U1 0 U2 0 PU TECH ASSN PULP PAPER IND INC PI NORCROSS PA 15 TECHNOLOGY PARK SOUTH, NORCROSS, GA 30092 SN 0734-1415 J9 TAPPI J JI TAPPI J. PD MAR PY 1996 VL 79 IS 3 BP 253 EP 260 PG 8 WC Materials Science, Paper & Wood SC Materials Science GA TY532 UT WOS:A1996TY53200026 ER PT J AU Krulevitch, P Ramsey, PB Makowiecki, DM Lee, AP Northrup, MA Johnson, GC AF Krulevitch, P Ramsey, PB Makowiecki, DM Lee, AP Northrup, MA Johnson, GC TI Mixed-sputter deposition of Ni-Ti-Cu shape memory films SO THIN SOLID FILMS LA English DT Article DE alloys; sputtering; stress; transmission electron microscopy ID ALLOYS; STRESS AB Ni-Ti-Cu shape memory films were mixed-sputter deposited from separate nickel, titanium, and copper targets, providing increased compositional flexibility. Shape memory characteristics, examined for films with 7 at.% Cu and 41-51 at.% Ti, were determined with temperature-controlled substrate-curvature measurements, and the microstructure was studied with transmission electron microscopy. The Ni-Ti-Cu films were found to have shape memory properties comparable with bulk materials, with transformation temperatures between 20 and 62 degrees C, a 10-13 degrees C hysteresis, and up to 330 MPa recoverable stress. C1 UNIV CALIF BERKELEY,DEPT MECH ENGN,BERKELEY,CA 94720. RP Krulevitch, P (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94551, USA. NR 29 TC 78 Z9 79 U1 0 U2 9 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAR PY 1996 VL 274 IS 1-2 BP 101 EP 105 DI 10.1016/0040-6090(95)07072-9 PG 5 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA UQ256 UT WOS:A1996UQ25600016 ER PT J AU Erdemir, A Erck, RA AF Erdemir, A. Erck, R. A. TI Effect of niobium interlayer on high-temperature sliding friction and wear of silver films on alumina SO TRIBOLOGY LETTERS LA English DT Article DE high-temperature friction; composite materials; solid lubricants; niobium interlayers AB In this study, we investigated the effect of a thin Nb bonding layer (15-20 nm thick) on the high-temperature sliding friction and wear performance of Ag films (similar to 1.5 mu m thick) produced on a-alumina (Al(2)O(3)) substrates by ion-beam assisted deposition (IBAD). The friction coefficients of Al(2)O(3) balls against the Ag-coated Al(2)O(3) fiats were 0.32 to 0.5 as opposed to 0.8 to 1.1 against the uncoated fiats. Furthermore, these Ag films reduced the wear rates of Al(2)O(3) balls by factors of 25 to similar to 2000, depending on test temperature. Wear of Ag-coated Al(2)O(3) flats was hard to measure after tests at temperatures up to 400 degrees C. At much higher temperatures (e. g., 600 degrees C) these Ag films (without a Nb layer) were removed from the sliding surfaces and lost their effectiveness; however, Ag films with the Nb bonding layer remained intact on the sliding surfaces of the Al(2)O(3) substrates even at 600 degrees C and continued to impart low friction and low wear. C1 [Erdemir, A.; Erck, R. A.] Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Erdemir, A (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. FU US Department of Energy [W-31-109-Eng-38] FX This work was supported by the US Department of Energy, under Contract W-31-109-Eng-38. NR 41 TC 4 Z9 4 U1 1 U2 1 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD MAR PY 1996 VL 2 IS 1 BP 23 EP 36 PG 14 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA V17SA UT WOS:000207955700003 ER PT J AU McGrath, WJ Abola, AP Toledo, DL Brown, MT Mangel, WF AF McGrath, WJ Abola, AP Toledo, DL Brown, MT Mangel, WF TI Characterization of human adenovirus proteinase activity in disrupted virus particles SO VIROLOGY LA English DT Article ID TYPE-2; PROTEASE; PEPTIDE; SPECIFICITY; SUBSTRATE AB Virus-coded proteinases are attractive targets for antiviral therapy; however, lack of quick, sensitive, quantitative, and selective assays for enzyme activity makes it difficult to characterize these proteinases and to screen large numbers of potential inhibitors. Here we describe new substrates for the adenovirus proteinase, fluorogenic Rhodamine-based substrates containing tetrapeptides corresponding to sequences cleaved in adenovirus precursor proteins. Proteinase activity in as few as 10(9) disrupted virions could be quantitatively detected in a 30-min assay. With the substrate (Leu-Arg-Gly-Gly-NH)(2)-Rhodamine, the K-m was 1.4 mu M, and the V-max was 3.24 pmol substrate hydrolyzed/sec/pmol virus. Enzyme activity was stimulated by dithiothreitol and inhibited by several serine-specific as well as cysteine-specific proteinase inhibitors. In a thiol protection experiment, the virion enzyme was shown to have a cysteine residue with an unusually low pK(a), a pK(a) similar to that of the active-site nucleophile of the cysteine proteinase papain. The curve of V-max as a function of pH is unlike the curve from papain and implied that there are at least three ionizable groups whose protonation state can affect catalysis - one with a pK(a) of 6.2, another with a pK(a) of 7.2, and a third with a pK(a) of 8.3. (C) 1996 Academic Press, Inc. C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. FU NIAID NIH HHS [AI26049] NR 36 TC 32 Z9 32 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0042-6822 J9 VIROLOGY JI Virology PD MAR 1 PY 1996 VL 217 IS 1 BP 131 EP 138 DI 10.1006/viro.1996.0100 PG 8 WC Virology SC Virology GA TY211 UT WOS:A1996TY21100014 PM 8599197 ER PT J AU Seregin, AV Bondar, VI Mattes, BR Yampolskii, YP Volkov, VV AF Seregin, AV Bondar, VI Mattes, BR Yampolskii, YP Volkov, VV TI Dual mechanism of equilibrium sorption in polymer systems: A generalized theory SO VYSOKOMOLEKULYARNYE SOEDINENIYA SERIYA A & SERIYA B LA Russian DT Editorial Material ID GLASSY-POLYMERS; GAS SORPTION; TRANSPORT; ISOTHERMS; DIOXIDE; MODEL AB A uniform system of model isotherms for gas sorption by glassy and rubberlike polymers was examined in a wide range of pressures and sorbate concentrations. For isoenergetic Langmuir sorption sites, a three-parameter equation, which is formally similar to the well-known BET equation, was derived. In the limiting cases, this basic equation leads to the classical equation describing the basic dual sorption model and a new equation describing the sorption; of gases by elastomers (this last equation is an alternative to that of the traditional Flory-Huggins model). The effect of energy distribution of the sorption sites on sorption isotherms was examined. For a uniform energy distribution of Langmuir sorption sites, a more general (three-parameter) equation was obtained, which, in the limiting case, also leads to the model that describes the behavior of gas-polymer system above the glass transition temperature. The validity of the basic equation and of the equation for elastomers was illustrated by way of examples involving poly(vinyltrimethylsilane)-ethane, poly(dimethylsiloxane)-propane, and polybutadiene-ethane. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Seregin, AV (reprint author), RUSSIAN ACAD SCI,AV TOPCHIEV PETROCHEM SYNTH INST,LENINSKII PR 29,MOSCOW 117912,RUSSIA. NR 31 TC 2 Z9 2 U1 3 U2 6 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0507-5475 J9 VYSOKOMOL SOEDIN JI Vysokomol. Soedin. PD MAR PY 1996 VL 38 IS 3 BP 535 EP 544 PG 10 WC Polymer Science SC Polymer Science GA UK324 UT WOS:A1996UK32400023 ER PT J AU Entry, JA Vance, NC Hamilton, MA Zabowski, D Watrud, LS Adriano, DC AF Entry, JA Vance, NC Hamilton, MA Zabowski, D Watrud, LS Adriano, DC TI Phytoremediation of soil contaminated with low concentrations of radionuclides SO WATER AIR AND SOIL POLLUTION LA English DT Article ID RADIOACTIVE CESIUM; RADIOCESIUM; ACCUMULATION; SR-90 AB Ecosystems throughout the world have been contaminated with radionuclides by aboveground nuclear testing, nuclear reactor accidents and nuclear power generation. Radioisotopes characteristic of nuclear fission, such as Cs-137 and Sr-90, that are released into the environment can become more concentrated as they move up the food chain often becoming human health hazards. Natural environmental processes will redistribute long lived radionuclides that are released into the environment among soil, plants and wildlife. Numerous studies have shown that Cs-137 and Sr-90 are not removed from the top 0.4 meters of soil even under high rainfall, and migration rate from the top few centimeters of soil is slow. The top 0.4 meters of the soil is where plant roots actively accumulate elements. Since plants are known to take up and accumulate Cs-137 and Sr-90, removal of these radionuclides from contaminated soils by plants could provide a reliable and economical method of remediation. One approach is to use fast growing plants inoculated with mycorrhizal fungi combined with soil organic amendments to maximize the plant accumulation and removal of radionuclides from contaminated soils, followed by harvest of above-ground portion of the plants. High temperature combustion would be used to oxidize plant material concentrating Cs-137 and Sr-90 in ash for disposal. When areas of land have been contaminated with radionuclides are large, using energy intensive engineering solutions to remediate huge volumes of soil is not feasible or economical. Plants are proposed as a viable and cost effective method to remove radionuclides from the soils that have been contaminated by nuclear testing and nuclear reactor accidents. C1 US FOREST SERV,USDA,PACIFIC NW RES STN,CORVALLIS,OR 97331. IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415. UNIV WASHINGTON,COLL FOREST RESOURCES,SEATTLE,WA 98195. US EPA,ENVIRONM RES LAB,TERR ECOL BRANCH,CORVALLIS,OR 97333. UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. RP Entry, JA (reprint author), AUBURN UNIV,DEPT AGRON & SOILS,AUBURN,AL 36849, USA. NR 40 TC 69 Z9 84 U1 2 U2 22 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 MAR PY 1996 VL 88 IS 1-2 BP 167 EP 176 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA UE413 UT WOS:A1996UE41300011 ER PT J AU Peyton, BM AF Peyton, BM TI Improved biomass distribution using pulsed injections of electron donor and acceptor SO WATER RESEARCH LA English DT Article DE in situ bioremediation; biofilm; porous media; nutrients; substrate; pulsing; co-metabolic degradation; nutrient delivery AB In situ bioremediation relies on the creation of contaminant-degrading biomass in subsurface soils. Pulsed injection of the electron donor and acceptor has been suggested as a method for evenly distributing biomass for more effective in situ bioremediation. Biofilms were developed in laboratory soil columns under both pulsed and continuous acetate and nitrate delivery using denitrifying conditions with acetate as the sole carbon and energy source. Separate experiments were conducted with either continuous or pulsed addition. Pulsing resulted in more evenly distributed biomass profiles as measured by both tryptic soy agar plate counts and total protein. RP Peyton, BM (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. OI Peyton, Brent/0000-0003-0033-0651 NR 5 TC 23 Z9 23 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0043-1354 J9 WATER RES JI Water Res. PD MAR PY 1996 VL 30 IS 3 BP 756 EP 758 DI 10.1016/0043-1354(95)00220-0 PG 3 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA TU580 UT WOS:A1996TU58000031 ER PT J AU Garbesi, K Sextro, RG Robinson, AL Wooley, JD Owens, JA Nazaroff, WW AF Garbesi, K Sextro, RG Robinson, AL Wooley, JD Owens, JA Nazaroff, WW TI Scale dependence of soil permeability to air: Measurement method and field investigation SO WATER RESOURCES RESEARCH LA English DT Article ID SPATIALLY-VARIABLE FIELDS; HYDRAULIC CONDUCTIVITIES; MULTISCALE SOURCES; RADON TRANSPORT; ENTRY; GAS; PRESSURE; BASEMENTS; MODEL; HOUSE AB This work investigates the dependence of soil permeability to air on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a Sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas phase contaminants through soils. C1 UNIV CALIF BERKELEY,DEPT CIVIL & ENVIRONM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,INDOOR ENVIRONM PROGRAM,BERKELEY,CA 94720. RI Yost, Russell/A-5937-2008; Nazaroff, William/C-4106-2008; Robinson, Allen/I-5713-2012; Robinson, Allen/M-3046-2014 OI Yost, Russell/0000-0002-1573-5822; Nazaroff, William/0000-0001-5645-3357; Robinson, Allen/0000-0003-1053-7090; Robinson, Allen/0000-0002-1819-083X NR 58 TC 24 Z9 24 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1996 VL 32 IS 3 BP 547 EP 560 DI 10.1029/95WR03637 PG 14 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA TX708 UT WOS:A1996TX70800005 ER PT J AU Gwo, JP Jardine, PM Wilson, GV Yeh, GT AF Gwo, JP Jardine, PM Wilson, GV Yeh, GT TI Using a multiregion model to study the effects of advective and diffusive mass transfer on local physical nonequilibrium and solute mobility in a structured soil SO WATER RESOURCES RESEARCH LA English DT Article ID DUAL-POROSITY MODEL; POROUS-MEDIA; TRANSPORT; FLOW; MOVEMENT; WATER; MACROPOROSITY; MESOPOROSITY; TERM AB Waste management problems for shallow land burial facilities in the humid eastern United States are usually complicated by slow but continuous movement of wastes through the soil matrix and discrete but rapid pulses of wastes through macropores and fractures. Multiple-pore-region models employed to describe flow and solute transport in the soils usually consist of multiple mass transfer coefficients that cannot be measured experimentally, and their effects on subsurface mass transport are poorly understood. The objective of this research was to study the individual and concurrent effects of interaggregate advection and diffusion on mass transport in a structured soil. The interactions of these two mass transfer processes and local solute concentration equilibrium are examined for a heterogeneous soil. Pore region water retention, hydraulic conductivity, and dispersivities, obtained from independent measurements and published calibration results, were used to test a novel three-pore-region, one-dimensional numerical model. Advective and diffusive mass transfer coefficients were estimated using mass transfer equations and fracture spacings published in the literature. The mass transfer coefficients were then varied systematically, and the sensitivity of local fluid pressure and solute concentration nonequilibrium to interregion mass transfer were analyzed. Our results indicated that time-dependent interaggregate advection and diffusion were important processes controlling solute mobility in heterogeneous media. Under transient flow conditions, interaggregate advection may reduce the significance of interaggregate diffusion that otherwise dominates interaggregate mass transfer under steady state conditions. Nonetheless, the equilibrium of local solute concentrations was 20 times more sensitive to diffusive mass transfer than to advect;ve mass transfer, which suggests that site characterization efforts should be directed more toward the former process. Unfortunately, characterization efforts of this type are not commonplace and if available are frequently ignored because they add a difficult reality to complex waste management problems. Since advective and diffusive mass transfer may be important processes limiting the efficiency of cleanup activities such as pump and treat, it is perhaps time to include the characterization of these processes and quantification of the timescale of physical nonequilibrium in site remediation efforts. C1 OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. UNIV TENNESSEE,DEPT PLANT & SOIL SCI,KNOXVILLE,TN 37901. PENN STATE UNIV,DEPT CIVIL & ENVIRONM ENGN,UNIVERSITY PK,PA 16802. NR 39 TC 46 Z9 46 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1996 VL 32 IS 3 BP 561 EP 570 DI 10.1029/95WR03397 PG 10 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA TX708 UT WOS:A1996TX70800006 ER PT J AU LaBolle, EM Fogg, GE Tompson, AFB AF LaBolle, EM Fogg, GE Tompson, AFB TI Random-walk simulation of transport in heterogeneous porous media: Local mass-conservation problem and implementation methods SO WATER RESOURCES RESEARCH LA English DT Article ID GROUNDWATER-FLOW MODELS; SOLUTE TRANSPORT; NUMERICAL-SIMULATION; PATH LINES AB The random-walk method for simulating solute transport in porous media is typically based on the assumption that the velocity and velocity-dependent dispersion tensor vary smoothly in space. However, in cases where sharp interfaces separate materials with contrasting hydraulic properties, these quantities may be discontinuous. Normally, velocities are interpolated to arbitrary particle locations when finite difference or finite element methods are used to solve the flow equation. The use of interpolation schemes that preserve discontinuities in velocity at material contacts can result in a random-walk model that does not locally conserve mass unless a correction is applied at these contacts. Test simulations of random-walk particle tracking with and without special treatment of material contacts demonstrate the problem. Techniques for resolving the problem, including interpolation schemes and a reflection principle, are reviewed and tested. Results from simulations of transport in porous media with discontinuities in the dispersion tensor show which methods satisfy continuity. Simulations of transport in two-dimensional heterogeneous porous media demonstrate the potentially significant effect of using a nonconservative model to compute spatial moments and breakthrough of a solute plume. C1 LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP LaBolle, EM (reprint author), UNIV CALIF DAVIS,DEPT GEOL,VEIHMEYER HALL,DAVIS,CA 95616, USA. NR 32 TC 177 Z9 183 U1 6 U2 33 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1996 VL 32 IS 3 BP 583 EP 593 DI 10.1029/95WR03528 PG 11 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA TX708 UT WOS:A1996TX70800008 ER PT J AU Rockhold, ML Rossi, RE Hills, RG AF Rockhold, ML Rossi, RE Hills, RG TI Application of similar media scaling and conditional simulation for modeling water flow and tritium transport at the Las Cruces Trench Site SO WATER RESOURCES RESEARCH LA English DT Article ID SOIL HYDRAULIC-PROPERTIES; SPATIAL VARIABILITY; SOLUTE TRANSPORT; UNSATURATED SOIL AB Similar media scaling and geostatistical analyses are used to characterize the spatial variability of soil hydraulic properties at the Las Cruces Trench Site in New Mexico. A simple method is described for conditioning the hydraulic properties used for unsaturated water flow and solute transport modeling, based on the spatial distributions of initial field-measured water contents and a set of scale-mean hydraulic parameters determined from the scaling analysis. This method is used to estimate hydraulic properties for numerical simulations of the latest field-scale flow and transport experiment conducted at the Las Cruces Trench Site. Relatively good matches between the observed and simulated flow and transport behavior are obtained without model calibration. The results of this study suggest that using similar media scaling in conjunction with the described conditioning procedure can significantly reduce the uncertainty in predictions of water flow and solute transport in spatially variable soils. C1 NEW MEXICO STATE UNIV,DEPT MECH ENGN,LAS CRUCES,NM 88003. RP Rockhold, ML (reprint author), PACIFIC NW NATL LAB,DEPT WATER & LAND RESOURCES,BATTELLE BLVD,POB 999,RICHLAND,WA 99352, USA. NR 32 TC 36 Z9 36 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD MAR PY 1996 VL 32 IS 3 BP 595 EP 609 DI 10.1029/95WR03398 PG 15 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA TX708 UT WOS:A1996TX70800009 ER PT J AU Schneider, M deBruijn, FJ AF Schneider, M deBruijn, FJ TI Rep-PCR mediated genomic fingerprinting of rhizobia and computer-assisted phylogenetic pattern analysis SO WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY LA English DT Article DE Azorhizobium caulinodans; DNA fingerprinting; genomic structure; nodules; PCR; phylogeny; repetitive DNA sequences; Rhizobium loti; Rhizobium meliloti; strain identification ID POLYMERASE CHAIN-REACTION; REPETITIVE DNA-SEQUENCES; ARBITRARY PRIMERS; BACTERIA; LOTI; POLYMORPHISMS; MUTANTS AB A rapid and reproducible method has been developed for genomic fingerprinting of rhizobia and other soil microbes interacting with plants. The method is based on the use of oligonucleotide primers, corresponding to conserved motifs in naturally occurring interspersed repetitive DNA elements in bacteria (rep-elements), and the polymerase chain reaction (rep-PCR). Rep-PCR results in the amplification of inter-element genomic DNA fragments of characteristic lengths and thereby generates a genomic fingerprint. These fingerprints resemble UPC bar code patterns, and can be used to identify bacteria at the sub-species and strain level, as well as for phylogenetic analyses. Here we show that highly characteristic and very reproducible rep-PCR generated genomic fingerprints can be obtained not only from purified genomic DNA, but also directly from rhizobial cells derived from liquid cultures or from colonies on plates, as well as from nodule tissue. We examine the effect of growth phase of the bacterial cells, serial subculturing and other parameters on the reproducibility of the rep-PCR fingerprinting protocol. Moreover, we describe the results of mixing experiments designed to determine if individual genomic fingerprints can be recognized in mixtures of strains. Lastly, we review the use of computer-based fragment detection and phylogenetic analysis packages to analyse rep-PCR generated genomic fingerprints of a collection of Rhizobium loti and Bradyrhizobium strains nodulating different Lotus spp. C1 NSF,CTR MICROBIAL ECOL,BLACKSBURG,VA. MICHIGAN STATE UNIV,DOE,PLANT RES LAB,E LANSING,MI 48824. MICHIGAN STATE UNIV,DEPT MICROBIOL,E LANSING,MI 48824. MICHIGAN STATE UNIV,GENET PROGRAM,E LANSING,MI 48824. NR 36 TC 40 Z9 41 U1 1 U2 8 PU RAPID SCIENCE PUBLISHERS PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8NH SN 0959-3993 J9 WORLD J MICROB BIOT JI World J. Microbiol. Biotechnol. PD MAR PY 1996 VL 12 IS 2 BP 163 EP 174 DI 10.1007/BF00364681 PG 12 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA UB665 UT WOS:A1996UB66500006 PM 24415164 ER PT J AU Ramlau, R Simon, A Schimek, GL McCarley, RE AF Ramlau, R Simon, A Schimek, GL McCarley, RE TI Chemical intergrowth of dimeric and trimeric clusters in reduced tin oxomolybdates: A study by high-resolution electron microscopy SO ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE LA English DT Article DE tin, oxygen, molybdenum; cluster compound; chemical intergrowth; twinning; superstructure; high-resolution electron microscopy ID CONDENSED MO6 OCTAHEDRA; CRYSTAL-STRUCTURE AB By high-resolution electron microscopy, chemical intergrowth was studied of dimeric Mo10O16 and trimeric Mo14O22 clusters in reduced tin oxomolybdates within the SnxMo10O16-SnyMo14O22 system. The variety of observed intergrowth patterns includes polysynthetically twinned structures as well as a number of different superstructures. For an orthorhombic superstructure formed by alternating layers of dimeric and trimeric clusters, the lattice parameters and the Sn content were determined. The chemical reason for the amazing abundance of structures in the considered system is discussed. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. US DOE,AMES LAB,AMES,IA 50011. RP Ramlau, R (reprint author), MAX PLANCK INST FESTKORPERFORSCH,HEISENBERGSTR 1,D-70569 STUTTGART,GERMANY. NR 17 TC 3 Z9 3 U1 0 U2 0 PU JOHANN AMBROSIUS BARTH VERLAG PI HEIDELBERG PA IM WEIHER 10, D-69121 HEIDELBERG, GERMANY SN 0044-2313 J9 Z ANORG ALLG CHEM JI Z. Anorg. Allg. Chem. PD MAR PY 1996 VL 622 IS 3 BP 437 EP 447 DI 10.1002/zaac.19966220310 PG 11 WC Chemistry, Inorganic & Nuclear SC Chemistry GA TZ817 UT WOS:A1996TZ81700009 ER PT J AU Hinderberger, S Xiao, SQ Westmacott, KH Dahmen, U AF Hinderberger, S Xiao, SQ Westmacott, KH Dahmen, U TI Effect of pre-aging on the evolution of Ge precipitates in an Al-1.8 at% Ge alloy SO ZEITSCHRIFT FUR METALLKUNDE LA English DT Article ID AL-GE; MORPHOLOGY; GERMANIUM; ALUMINUM AB The shape distribution of Ge precipitates in a quenched and ag ed Al-1.8 at.% Ce alloy was characterized by transmission electron microscopy. In agreement with previous investigations, at least six different precipitate morphologies were distinguished: tetrahedra, octahedra and triangular plates all with the cube-cube orientation relationship; as well as laths along [100] Al directions, laths along [110] Al directions and plates on {100} Al planes, with three different orientation relationships, respectively. The distribution of precipitate shapes was found to depend strongly on the heat treatment schedule. After quenching to 0 degrees C, samples aged at 200 degrees C exhibited predominantly triangular plates and tetrahedra and were insensitive to pre-aging at room temperature. By comparison, samples aged at 250 and especially at 300 degrees C contained mainly lath-shaped precipitates after short pre-aging times, but a sharply increasing fraction of tetrahedra, octahedra and triangular plates for longer pre-aging times. When the temperature of the quench bath was raised from 0 to 40 degrees C, samples aged at 200 degrees C remained unchanged whereas samples aged at 250 and 300 degrees C retained only lath shaped precipitates. Quenching directly to the three aging temperatures changed the precipitate distribution to a coarse array of large {100} plates. RP Hinderberger, S (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720, USA. NR 20 TC 17 Z9 17 U1 0 U2 2 PU CARL HANSER VERLAG PI MUNICH PA KOLBERGERSTRASSE 22, POSTFACH 860420, W-8163 MUNICH, GERMANY SN 0044-3093 J9 Z METALLKD JI Z. Metallk. PD MAR PY 1996 VL 87 IS 3 BP 161 EP 169 PG 9 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA UD373 UT WOS:A1996UD37300002 ER PT J AU Bentaleb, M Schulz, N Lubkiewicz, E Durell, JL Pearson, CJ Phillips, WR Shannon, J Varley, BJ Ahmad, I Lister, CJ Morss, LR Nash, KL Williams, CW AF Bentaleb, M Schulz, N Lubkiewicz, E Durell, JL Pearson, CJ Phillips, WR Shannon, J Varley, BJ Ahmad, I Lister, CJ Morss, LR Nash, KL Williams, CW TI Search for octupole deformation in neutron-rich Xe isotopes SO ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI LA English DT Article ID NUCLEI; SHAPES AB A search for octupole deformation in neutron-rich Xe isotopes has been conducted through prompt gamma-ray spectroscopy of secondary fragments produced in the spontaneous fission of Cm-248. nh, spectrometer consisted of the Eurogam 1 array and a set of 5 LEPS detectors. Level schemes were constructed for Xe isotopes with mass number ranging from 140 to 144 and excited states for Xe-143,Xe-144 nuclei were observed for the first time. None of the level schemes exhibit an alternating parity quasimolecular band, a feature usually expected in nuclei in which octupole correlation effects are strong enough to produce stable octupole deformation. For several isotopes, structures observed in the level schemes are consistent with an octupole softness of the nuclei. C1 JAGIELLONIAN UNIV,INST PHYS,PL-30059 KRAKOW,POLAND. UNIV MANCHESTER,DEPT PHYS,MANCHESTER M13 9PL,LANCS,ENGLAND. ARGONNE NATL LAB,ARGONNE,IL 60439. RP Bentaleb, M (reprint author), UNIV STRASBOURG 1,CTR RECH NUCL,CNRS,IN2P3,BP 28,F-67037 STRASBOURG 2,FRANCE. NR 20 TC 20 Z9 21 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0939-7922 J9 Z PHYS A-HADRON NUCL JI Z. Phys. A.-Hadrons Nuclei PD MAR PY 1996 VL 354 IS 2 BP 143 EP 151 DI 10.1007/BF02769506 PG 9 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UB022 UT WOS:A1996UB02200007 ER PT J AU Fotiades, N Harissopulos, S Kalfas, CA Kossionides, S Papadopoulos, CT Vlastou, R Serris, M SharpeySchafer, JF Joyce, CW Beausang, CW Dagnall, PJ Forsyth, PD Gale, SJ Jones, PM Paul, ES Twin, PJ Simpson, J Cullen, DM Fallon, P Riley, MA Clark, RM Hauschild, K Wadsworth, R AF Fotiades, N Harissopulos, S Kalfas, CA Kossionides, S Papadopoulos, CT Vlastou, R Serris, M SharpeySchafer, JF Joyce, CW Beausang, CW Dagnall, PJ Forsyth, PD Gale, SJ Jones, PM Paul, ES Twin, PJ Simpson, J Cullen, DM Fallon, P Riley, MA Clark, RM Hauschild, K Wadsworth, R TI High spin structures in Hg-194 SO ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI LA English DT Article ID DIPOLE ROTATIONAL BANDS; COLLECTIVE OBLATE; 1ST OBSERVATION; NUCLEI; REGION; PB-196 AB High spin states in the isotope Hg-194 were populated using the Nd-150 (Ca-48,4n) reaction at a beam energy of 213 MeV. The analysis of gamma-gamma coincidences has revealed two new structures at excitation energies above 6 MeV and at moderate spin. The two structures are a manifestation of the deviation of nucleus from the collective rotation which dominates its lower excitation behaviour. A comparison with similar structures in the neighbouring Hg isotopes is also attempted. C1 NATL TECH UNIV ATHENS,GR-15773 ATHENS,GREECE. UNIV LIVERPOOL,OLIVER LODGE LAB,LIVERPOOL L69 3BX,MERSEYSIDE,ENGLAND. SERC,DARESBURY LAB,CCL,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. FLORIDA STATE UNIV,TALLAHASSEE,FL 32306. UNIV YORK,DEPT PHYS,YORK YO1 5DD,N YORKSHIRE,ENGLAND. RP Fotiades, N (reprint author), NATL CTR SCI RES DEMOKRITOS,INST NUCL PHYS,GR-15310 ATHENS,GREECE. RI Hauschild, Karl/A-6726-2009; Harissopulos, Sotirios/G-9541-2011 OI Harissopulos, Sotirios/0000-0003-4022-7595 NR 26 TC 13 Z9 13 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0939-7922 J9 Z PHYS A-HADRON NUCL JI Z. Phys. A.-Hadrons Nuclei PD MAR PY 1996 VL 354 IS 2 BP 169 EP 175 DI 10.1007/BF02769510 PG 7 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA UB022 UT WOS:A1996UB02200011 ER PT J AU Derrick, M Krakauer, D Magill, S Mikunas, D Musgrave, B Repond, J Stanek, R Talaga, RL Zhang, H Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Bruni, P Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Corradi, M Gialas, I Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Polini, A Sartorelli, G Garcia, YZ Zichichi, A Bornheim, A Crittenden, J Desch, K Diekmann, B Doeker, T Eckert, M Feld, L Frey, A Geerts, M Grothe, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Katz, UF Mengel, S Mollen, J Paul, E Pfeiffer, M Rembser, C Schramm, D Stamm, J Wedemeyer, R CampbellRobson, S Cassidy, A Cottingham, WN Dyce, N Foster, B George, S Hayes, ME Heath, GP Heath, HF Morgado, CJS OMara, JA Piccioni, D Roff, DG Tapper, RJ Yoshida, R Rau, RR Arneodo, M Ayad, R Capua, M Garfagnini, A Iannotti, L Schioppa, N Susinno, G Bernstein, A Caldwell, A Cartiglia, N Parsons, JA Ritz, S Sciulli, F Straub, PB Wai, L Yang, S Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Piotrzkowski, K Zachara, M Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowalski, T Przybycien, M RulikowskaZarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Beier, H Bienlein, JK Coldewey, C Deppe, O Desler, K Drews, G Flasinski, M Gilkinson, DJ Glasman, C Gottlicher, P GrosseKnetter, J Gutjahr, B Haas, T Hain, W Hasell, D Hessling, H Iga, Y Johnson, KF Joos, P Kasemann, M Klanner, R Koch, W Kopke, L Kotz, U Kowalski, H Labs, J Ladage, A Lohr, B Lowe, M Luke, D Mainusch, J Manczak, O Monteiro, T Ng, JST Nickel, S Notz, D Ohrenberg, K Roco, M Rohde, M Roldan, J Schneekloth, U Schulz, W Selonke, F Stiliaris, E Surrow, B Voss, T Westphal, D Wolf, G Youngman, C Zeuner, W Zhou, JF Grabosch, HJ Kharchilava, A Leich, A Mari, SM Mattingly, MCK Meyer, A Schlenstedt, S Wulff, N Barbagli, G Gallo, E Pelfer, P Maccarrone, G DePasquale, S Votano, L Bamberger, A Eisenhardt, S Freidhof, A SoldnerRembold, S Schroeder, J Trefzger, T Bromley, JT Brook, NH Bussey, PJ Doyle, AT Saxon, DH Utley, ML Wilson, AS Dannemann, A Holm, U Horstmann, D Neumann, T Sinkus, R Wick, K Badura, E Burow, BD Hagge, L Lohrmann, E Milewski, J Nakahata, M Pavel, N Poelz, G Schott, W Zetsche, F Bacon, TC Bruemmer, N Butterworth, I Harris, VL Hung, BYH Long, KR Miller, DB Morawitz, PPO Prinias, A Sedgbeer, JK Whitfield, AF Mallik, U McCliment, E Wang, MZ Wang, SM Wu, JT Cloth, P Filges, D An, SH Cho, GH Ko, BJ Lee, SB Nam, SW Park, HS Park, SK Imlay, R Kartik, S Kim, HJ McNeil, RR Metcalf, W Nadendla, VK Barreiro, F Cases, G Fernandez, JP Graciani, R Hernandez, JM Hervas, L Labarga, L Martinez, M delPeso, J Puga, J Terron, J deTroconiz, JF Smith, GR Corriveau, F Hanna, DS Hartmann, J Hung, LW Lim, JN Matthews, CG Patel, PM Sinclair, LE Stairs, DG StLaurent, M Ullmann, R Zacek, G Bashkirov, V Dolgoshein, BA Stifutkin, A Bashindzhagyan, GL Ermolov, PF Gladilin, LK Golubkov, YA Kobrin, VD Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Savin, AA Shcheglova, LM Solomin, AN Zotov, NP Botje, M Chlebana, F Dake, A Engelen, J deKamps, M Kooijman, P Kruse, A Tiecke, H Verkerke, W Vreeswijk, M Wiggers, L deWolf, E vanWoudenberg, R Acosta, D Bylsma, B Durkin, LS Gilmore, J Honscheid, K Li, C Ling, TY McLean, KW Nylander, P Park, IH Romanowski, TA Seidlein, R Bailey, DS Byrne, A Cashmore, RJ CooperSarkar, AM Devenish, RCE Harnew, N Lancaster, M Lindemann, L McFall, JD Nath, C Noyes, VA Quadt, A Tickner, JR Uijterwaal, H Walczak, R Waters, DS Wilson, FF Yip, T Abbiendi, G Bertolin, A Brugnera, R Carlin, R DalCorso, F DeGiorgi, M Dosselli, U Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Bulmahn, J Butterworth, JM Feild, RG Oh, BY Okrasinski, JR Whitmore, JJ DAgostini, G Marini, G Nigro, A Tassi, E Hart, JC McCubbin, NA Prytz, K Shah, TP Short, TL Barberis, E Dubbs, T Heusch, C VanHook, M Lockman, W Rahn, JT Sadrozinski, HFW Seiden, A Williams, DC Biltzinger, J Seifert, RJ Schwarzer, O Walenta, AH Zech, G Abramowicz, H Briskin, G Dagan, S Levy, A Fleck, JI Hasegawa, T Hazumi, M Ishii, T Kuze, M Mine, S Nagasawa, Y Nakao, M Suzuki, I Tokushuku, K Yamada, S Yamazaki, Y Chiba, M Hamatsu, R Hirose, T Homma, K Kitamura, S Nakamitsu, Y Yamauchi, K Cirio, R Costa, M Ferrero, MI Lamberti, L Maselli, S Peroni, C Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Benard, F Brkic, M Hartner, GF Joo, KK Levman, GM Martin, JF Orr, RS Polenz, S Sampson, CR Teuscher, RJ Catterall, CD Jones, TW Kaziewicz, PB Lane, JB Saunders, RL Shulman, J Blankenship, K Lu, B Mo, LW Bogusz, W Charchula, K Ciborowski, J Gajewski, J Grzelak, G Kasprzak, M Krzyzanowski, M Muchorowski, K Nowak, RJ Pawlak, JM Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Eisenberg, Y Karshon, U Revel, D ZerZion, D Ali, I Badgett, WF Behrens, B Dasu, S Fordham, C Foudas, C Goussiou, A Loveless, RJ Reeder, DD Silverstein, S Smith, WH Vaiciulis, A Wodarczyk, M Tsurugai, T Bhadra, S Cardy, ML Fagerstroem, CP Frisken, WR Khakzad, M Murray, WN Schmidke, WB AF Derrick, M Krakauer, D Magill, S Mikunas, D Musgrave, B Repond, J Stanek, R Talaga, RL Zhang, H Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Bruni, P Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Corradi, M Gialas, I Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Polini, A Sartorelli, G Garcia, YZ Zichichi, A Bornheim, A Crittenden, J Desch, K Diekmann, B Doeker, T Eckert, M Feld, L Frey, A Geerts, M Grothe, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Katz, UF Mengel, S Mollen, J Paul, E Pfeiffer, M Rembser, C Schramm, D Stamm, J Wedemeyer, R CampbellRobson, S Cassidy, A Cottingham, WN Dyce, N Foster, B George, S Hayes, ME Heath, GP Heath, HF Morgado, CJS OMara, JA Piccioni, D Roff, DG Tapper, RJ Yoshida, R Rau, RR Arneodo, M Ayad, R Capua, M Garfagnini, A Iannotti, L Schioppa, N Susinno, G Bernstein, A Caldwell, A Cartiglia, N Parsons, JA Ritz, S Sciulli, F Straub, PB Wai, L Yang, S Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Piotrzkowski, K Zachara, M Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowalski, T Przybycien, M RulikowskaZarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Beier, H Bienlein, JK Coldewey, C Deppe, O Desler, K Drews, G Flasinski, M Gilkinson, DJ Glasman, C Gottlicher, P GrosseKnetter, J Gutjahr, B Haas, T Hain, W Hasell, D Hessling, H Iga, Y Johnson, KF Joos, P Kasemann, M Klanner, R Koch, W Kopke, L Kotz, U Kowalski, H Labs, J Ladage, A Lohr, B Lowe, M Luke, D Mainusch, J Manczak, O Monteiro, T Ng, JST Nickel, S Notz, D Ohrenberg, K Roco, M Rohde, M Roldan, J Schneekloth, U Schulz, W Selonke, F Stiliaris, E Surrow, B Voss, T Westphal, D Wolf, G Youngman, C Zeuner, W Zhou, JF Grabosch, HJ Kharchilava, A Leich, A Mari, SM Mattingly, MCK Meyer, A Schlenstedt, S Wulff, N Barbagli, G Gallo, E Pelfer, P Maccarrone, G DePasquale, S Votano, L Bamberger, A Eisenhardt, S Freidhof, A SoldnerRembold, S Schroeder, J Trefzger, T Bromley, JT Brook, NH Bussey, PJ Doyle, AT Saxon, DH Utley, ML Wilson, AS Dannemann, A Holm, U Horstmann, D Neumann, T Sinkus, R Wick, K Badura, E Burow, BD Hagge, L Lohrmann, E Milewski, J Nakahata, M Pavel, N Poelz, G Schott, W Zetsche, F Bacon, TC Bruemmer, N Butterworth, I Harris, VL Hung, BYH Long, KR Miller, DB Morawitz, PPO Prinias, A Sedgbeer, JK Whitfield, AF Mallik, U McCliment, E Wang, MZ Wang, SM Wu, JT Cloth, P Filges, D An, SH Cho, GH Ko, BJ Lee, SB Nam, SW Park, HS Park, SK Imlay, R Kartik, S Kim, HJ McNeil, RR Metcalf, W Nadendla, VK Barreiro, F Cases, G Fernandez, JP Graciani, R Hernandez, JM Hervas, L Labarga, L Martinez, M delPeso, J Puga, J Terron, J deTroconiz, JF Smith, GR Corriveau, F Hanna, DS Hartmann, J Hung, LW Lim, JN Matthews, CG Patel, PM Sinclair, LE Stairs, DG StLaurent, M Ullmann, R Zacek, G Bashkirov, V Dolgoshein, BA Stifutkin, A Bashindzhagyan, GL Ermolov, PF Gladilin, LK Golubkov, YA Kobrin, VD Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Savin, AA Shcheglova, LM Solomin, AN Zotov, NP Botje, M Chlebana, F Dake, A Engelen, J deKamps, M Kooijman, P Kruse, A Tiecke, H Verkerke, W Vreeswijk, M Wiggers, L deWolf, E vanWoudenberg, R Acosta, D Bylsma, B Durkin, LS Gilmore, J Honscheid, K Li, C Ling, TY McLean, KW Nylander, P Park, IH Romanowski, TA Seidlein, R Bailey, DS Byrne, A Cashmore, RJ CooperSarkar, AM Devenish, RCE Harnew, N Lancaster, M Lindemann, L McFall, JD Nath, C Noyes, VA Quadt, A Tickner, JR Uijterwaal, H Walczak, R Waters, DS Wilson, FF Yip, T Abbiendi, G Bertolin, A Brugnera, R Carlin, R DalCorso, F DeGiorgi, M Dosselli, U Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Bulmahn, J Butterworth, JM Feild, RG Oh, BY Okrasinski, JR Whitmore, JJ DAgostini, G Marini, G Nigro, A Tassi, E Hart, JC McCubbin, NA Prytz, K Shah, TP Short, TL Barberis, E Dubbs, T Heusch, C VanHook, M Lockman, W Rahn, JT Sadrozinski, HFW Seiden, A Williams, DC Biltzinger, J Seifert, RJ Schwarzer, O Walenta, AH Zech, G Abramowicz, H Briskin, G Dagan, S Levy, A Fleck, JI Hasegawa, T Hazumi, M Ishii, T Kuze, M Mine, S Nagasawa, Y Nakao, M Suzuki, I Tokushuku, K Yamada, S Yamazaki, Y Chiba, M Hamatsu, R Hirose, T Homma, K Kitamura, S Nakamitsu, Y Yamauchi, K Cirio, R Costa, M Ferrero, MI Lamberti, L Maselli, S Peroni, C Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Benard, F Brkic, M Hartner, GF Joo, KK Levman, GM Martin, JF Orr, RS Polenz, S Sampson, CR Teuscher, RJ Catterall, CD Jones, TW Kaziewicz, PB Lane, JB Saunders, RL Shulman, J Blankenship, K Lu, B Mo, LW Bogusz, W Charchula, K Ciborowski, J Gajewski, J Grzelak, G Kasprzak, M Krzyzanowski, M Muchorowski, K Nowak, RJ Pawlak, JM Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Eisenberg, Y Karshon, U Revel, D ZerZion, D Ali, I Badgett, WF Behrens, B Dasu, S Fordham, C Foudas, C Goussiou, A Loveless, RJ Reeder, DD Silverstein, S Smith, WH Vaiciulis, A Wodarczyk, M Tsurugai, T Bhadra, S Cardy, ML Fagerstroem, CP Frisken, WR Khakzad, M Murray, WN Schmidke, WB TI Inclusive charged particle distributions in deep inelastic scattering events at HERA SO ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS LA English DT Article ID MUON-PROTON-SCATTERING; LUND MONTE-CARLO; SIMULTANEOUS PATTERN-RECOGNITION; ZEUS BARREL CALORIMETER; KALMAN FILTERING METHOD; DIFFRACTION DISSOCIATION; TRANSVERSE-MOMENTUM; JET FRAGMENTATION; E+E-PHYSICS; HADRONS AB A measurement of inclusive charged particle distributions in deep inelastic ep scattering for gamma*p centre-of-mass energies 75 < W < 175 GeV and momentum transfer squared 10 < Q(2) < 160 GeV2 from the ZEUS detector at HERA is presented. The differential charged particle rates in the gamma*p centre-of-mass system as a function of the scaled longitudinal momentum, x(F), and of the transverse momentum, p(t)* and [p(t)(*2)], as a function of x(F), W and Q(2) are given, Separate distributions are shown for events with (LRG) and without (NRG) a rapidity gap with respect to the proton direction. The data are compared with results from experiments at lower beam energies, with the naive quark parton model and with parton models including perturbative QCD corrections, The comparison shows the importance of the higher order QCD processes. Significant differences of the inclusive charged particle rates between NRG and LRG events at the same W are observed, The value of [p(t)(*2)] for LRG events with a hadronic mass M(X), which excludes the forward produced baryonic system, is similar to the [p(t)(*2)] value observed in fixed target experiments at W approximate to M(X). C1 UNIV BOLOGNA, BOLOGNA, ITALY. IST NAZL FIS NUCL, I-40126 BOLOGNA, ITALY. UNIV BONN, INST PHYS, W-5300 BONN, GERMANY. UNIV BRISTOL, HH WILLS PHYS LAB, BRISTOL BS8 1TL, AVON, ENGLAND. BNL, UPTON, NY 11973 USA. UNIV CALABRIA, DEPT PHYS, I-87036 COSENZA, ITALY. IST NAZL FIS NUCL, COSENZA, ITALY. COLUMBIA UNIV, NEVIS LABS, IRVINGTON, NY USA. INST PHYS NUCL, KRAKOW, POLAND. ACAD MIN & MET, FAC PHYS & NUCL TECHNIQUES, KRAKOW, POLAND. JAGIELLONIAN UNIV, DEPT PHYS, KRAKOW, POLAND. DESY, W-2000 HAMBURG, GERMANY. DESY ZEUTHEN, INST HOCHENERGIEPHYS, O-1615 ZEUTHEN, GERMANY. UNIV FLORENCE, FLORENCE, ITALY. IST NAZL FIS NUCL, I-50125 FLORENCE, ITALY. IST NAZL FIS NUCL, LAB NAZL FRASCATI, I-00044 FRASCATI, ITALY. UNIV FREIBURG, FAK PHYS, W-7800 FREIBURG, GERMANY. UNIV GLASGOW, DEPT PHYS & ASTRON, GLASGOW, LANARK, SCOTLAND. UNIV HAMBURG, INST EXPTL PHYS 1, HAMBURG, GERMANY. UNIV HAMBURG, INST EXPTL PHYS 2, HAMBURG, GERMANY. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED, HIGH ENERGY NUCL PHYS GRP, LONDON, ENGLAND. UNIV IOWA, DEPT PHYS & ASTRON, IOWA CITY, IA 52242 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST KERNPHYS, W-5170 JULICH, GERMANY. KOREA UNIV, SEOUL 136701, SOUTH KOREA. LOUISIANA STATE UNIV, DEPT PHYS & ASTRON, BATON ROUGE, LA 70803 USA. UNIV AUTONOMA MADRID, DEPT FIS TEOR, MADRID, SPAIN. UNIV MANITOBA, DEPT PHYS, WINNIPEG, MB R3T 2N2, CANADA. MCGILL UNIV, DEPT PHYS, MONTREAL, PQ, CANADA. MOSCOW PHYS ENGN INST, MOSCOW, RUSSIA. MOSCOW MV LOMONOSOV STATE UNIV, INST NUCL PHYS, MOSCOW, RUSSIA. NIKHEF, AMSTERDAM, NETHERLANDS. UNIV AMSTERDAM, AMSTERDAM, NETHERLANDS. OHIO STATE UNIV, DEPT PHYS, COLUMBUS, OH 43210 USA. UNIV OXFORD, DEPT PHYS, OXFORD, ENGLAND. UNIV PADUA, DIPARTIMENTO FIS, PADUA, ITALY. IST NAZL FIS NUCL, PADUA, ITALY. PENN STATE UNIV, DEPT PHYS, UNIVERSITY PK, PA 16802 USA. UNIV ROMA LA SAPIENZA, DIPARTIMENTO FIS, I-00185 ROME, ITALY. IST NAZL FIS NUCL, ROME, ITALY. RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. UNIV CALIF SANTA CRUZ, SANTA CRUZ, CA 95064 USA. UNIV GESAMTHSCH SIEGEN, FACHBEREICH PHYS, W-5900 SIEGEN, GERMANY. TEL AVIV UNIV, SCH PHYS, IL-69978 TEL AVIV, ISRAEL. UNIV TOKYO, INST NUCL STUDY, TOKYO, JAPAN. TOKYO METROPOLITAN UNIV, DEPT PHYS, TOKYO, JAPAN. UNIV TURIN, DIPARTIMENTO FIS SPERIMENTALE, TURIN, ITALY. IST NAZL FIS NUCL, I-10125 TURIN, ITALY. UNIV TURIN, FAC SCI 2, ALESSANDRIA, ITALY. IST NAZL FIS NUCL, ALESSANDRIA, ITALY. UNIV TORONTO, DEPT PHYS, TORONTO, ON, CANADA. UCL, DEPT PHYS & ASTRON, LONDON, ENGLAND. VIRGINIA POLYTECH INST & STATE UNIV, DEPT PHYS, BLACKSBURG, VA 24061 USA. UNIV WARSAW, INST EXPTL PHYS, WARSAW, POLAND. INST NUCL STUDIES, PL-00681 WARSAW, POLAND. WEIZMANN INST SCI, INST PARTICLE PHYS, IL-76100 REHOVOT, ISRAEL. UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. MEIJI GAKUIN UNIV, FAC GEN EDUC, YOKOHAMA, KANAGAWA, JAPAN. YORK UNIV, DEPT PHYS, N YORK, ON M3J 1P3, CANADA. IROE FLORENCE, FLORENCE, ITALY. RP ARGONNE NATL LAB, 9700 S CASS AVE, ARGONNE, IL 60439 USA. RI Solomin, Anatoly/C-3072-2016; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; Bashkirov, Vladimir/A-4818-2008; De Pasquale, Salvatore/B-9165-2008; Lancaster, Mark/C-1693-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Hernandez Calama, Jose Maria/H-9127-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016 OI Graciani Diaz, Ricardo/0000-0001-7166-5198; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Lancaster, Mark/0000-0002-8872-7292; Utley, Martin/0000-0001-9928-1516; De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; Hernandez Calama, Jose Maria/0000-0001-6436-7547; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240 NR 64 TC 38 Z9 38 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0170-9739 J9 Z PHYS C PART FIELDS JI Z. Phys. C-Part. Fields PD MAR PY 1996 VL 70 IS 1 BP 1 EP 15 DI 10.1007/s002880050075 PG 15 WC Physics, Particles & Fields SC Physics GA UB408 UT WOS:A1996UB40800001 ER PT J AU Lear, KL Mar, A Choquette, KD Kilcoyne, SP Schneider, RP Geib, KM AF Lear, KL Mar, A Choquette, KD Kilcoyne, SP Schneider, RP Geib, KM TI High-frequency modulation of oxide-confined vertical cavity surface emitting lasers SO ELECTRONICS LETTERS LA English DT Article DE vertical cavity surface emitting lasers; semiconductor junction lasers; optical modulation AB High-speed studies of packaged, submilliampere threshold, oxide-confined vertical cavity surface emitting lasers show modulation bandwidths > 16 GHz. Very high modulation current efficiency factors occur at low bias but decrease as the modulation bandwidth and frequency of the relative intensity noise peak saturate at higher currents. RP Lear, KL (reprint author), SANDIA NATL LABS,PHOTON RES DEPT 1312,MS 0603,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 11 TC 117 Z9 116 U1 1 U2 5 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD FEB 29 PY 1996 VL 32 IS 5 BP 457 EP 458 DI 10.1049/el:19960334 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA UL771 UT WOS:A1996UL77100030 ER PT J AU Choquette, KD Hou, HQ Lear, KL Chui, HC Geib, KM Mar, A Hammons, BE AF Choquette, KD Hou, HQ Lear, KL Chui, HC Geib, KM Mar, A Hammons, BE TI Self-pulsing oxide-confined vertical-cavity lasers with ultralow operating current SO ELECTRONICS LETTERS LA English DT Article DE vertical cavity surface emitting lasers; semiconductor junction lasers AB Selectively oxidised vertical-cavity lasers which exhibit self-pulsating lasing at currents as low as 470 nA are reported. Characteristics including linearly polarised emission, narrow linewidths and coherent near- and far-field diffraction indicate that these devices operate as lasers at DC currents < 1 mu A. Although self-pulsating lasing initiates at submicroampere average current, the injection current during the optical pulse can be > 1 mA. RP Choquette, KD (reprint author), SANDIA NATL LABS,PHOTON RES DEPT,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 10 TC 13 Z9 13 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD FEB 29 PY 1996 VL 32 IS 5 BP 459 EP 460 DI 10.1049/el:19960333 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA UL771 UT WOS:A1996UL77100031 ER PT J AU Jia, QX Wu, XD Reagor, D Foltyn, SR Mombourquette, C Peterson, DE AF Jia, QX Wu, XD Reagor, D Foltyn, SR Mombourquette, C Peterson, DE TI Edge-geometry SNS DC SQUIDs using Ag-doped YBa2Cu3O7-x electrodes SO ELECTRONICS LETTERS LA English DT Article DE superconducting thin films; SQUIDS AB Josephson junctions and DC SQUIDs were fabricated in an edge-geometry superconductor/normal-metal/superconductor configuration using Ag-doped YBa2Cu3O7-x electrodes and a PrBa2Cu3O7-x N-layer. A differential voltage modulation of over 150 mu V/Phi(0) at 75K was achieved. The flux noise was 30 similar to 40 mu Phi(0)Hz(-1/2) measured with DC bias at a Frequency of 1Hz. RP Jia, QX (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,G755,LOS ALAMOS,NM 87545, USA. RI Jia, Q. X./C-5194-2008 NR 4 TC 8 Z9 8 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD, ENGLAND SG1 2AY SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD FEB 29 PY 1996 VL 32 IS 5 BP 499 EP 501 DI 10.1049/el:19960313 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA UL771 UT WOS:A1996UL77100058 ER PT J AU Kelly, C Szalda, DJ Creutz, C Schwarz, HA Sutin, N AF Kelly, C Szalda, DJ Creutz, C Schwarz, HA Sutin, N TI Electron transfer barriers for ground- and excited-state redox couples: Trans-dioxo(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) osmium(VI)/osmium(V) SO INORGANICA CHIMICA ACTA LA English DT Article DE pulse radiolysis; electron transfer; osmium complexes; oxo complexes; azamacrocycle complexes ID TETRADENTATE TERTIARY-AMINES; AQUEOUS-SOLUTIONS; OXO COMPLEXES; EXCHANGE; LIGANDS; CRYSTAL; 1,4,8,11-TETRAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECANE; ELECTROCHEMISTRY; PHOTOCHEMISTRY; REDUCTION AB Pulse radiolysis methods were used to measure rate and equilibrium constants for the reaction of the Os-VI(TMC)(O)(2)(2+)/Os-V(TMC)(O)(2)(+) couple with semiquinone/quinone couples, Os-VI(TMC)(O)(2)(2+) + Q(-)reversible arrow Os-V(TMC)(O)(2)(+) + Q, where TMC = tetramethylcyclam and Q is 1,4-benzoquinone or 2-methyl-1,4-benzoquinone. This work yields a self-exchange rate constant of 1.1 x 10(6) M(-1) s(-1) and a reduction potential of +0.048 V versus NHE for the dioxoosmium ground-state couple at 0.1 M ionic strength and 25 degrees C. [Os(TMC)(O)(2)](PF6)(2) crystallizes in the monoclinic space group, P2(1)/c, with a = 6.712(2) Angstrom, b = 17.756(6) Angstrom, c = 10.150(2) Angstrom, beta = 95.59(2)degrees and Z = 2. Single crystal X-ray diffraction results for the PF6- salt of the Os-VI(TMC)(O)(2)(2+) indicate that the dominant isomer present in the crystal is the RSSR isomer in which one pair of N-methyl groups is 'up' while the other is 'down'. The average Os-O and Os-N distances are 1.735(6) and 2.126(8) Angstrom, respectively. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. BARUCH COLL,DEPT NAT SCI,NEW YORK,NY 10010. NR 28 TC 5 Z9 5 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD FEB 29 PY 1996 VL 243 IS 1-2 BP 39 EP 45 DI 10.1016/0020-1693(95)04890-1 PG 7 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UM713 UT WOS:A1996UM71300008 ER PT J AU Maverick, AW Butler, LG Lewis, W Gallegos, CH Goettee, JD Rickel, DG Fowler, CM AF Maverick, AW Butler, LG Lewis, W Gallegos, CH Goettee, JD Rickel, DG Fowler, CM TI Zeeman-effect studies of the electronic absorption spectrum of octachlorodirhenate(2-) (Re Re) in pulsed 50-Tesla magnetic fields SO INORGANICA CHIMICA ACTA LA English DT Article DE electronic absorption spectra; quadruply bonded metal complexes; Zeeman-effect study; visible spectrum of Re2Cl82- ID CRYSTAL-STRUCTURE; QUADRUPLE BONDS; SPECTROSCOPY; COMPLEXES; STATES AB Electronic absorption spectra have been measured for crystals of (Bu(4)N)(2)[Re2Cl8] at 3.8 K in pulsed magnetic fields (pulse duration ca. 10 ms; field strength to 50 T). Spectra were measured in the 530-600 nm ('Band I') and 435-500 nm ('Band II') regions, where well resolved vibrational fine structure had been noted in previous spectroscopic studies. Application of magnetic fields up to 50 T caused no measurable splittings or shifts in these two absorption bands. This indicates that both bands are attributable to spin-allowed electronic transitions, since spin-forbidden transitions would be expected to show Zeeman splitting. Possible assignments for Bands I and II include transitions to two (1)E(g) excited states [(1)(pi,delta*) and (1)(delta,pi*)], as previously suggested by Bursten et al. (B.E. Bursten, EA. Cotton, P.E. Fanwick and G.G. Stanley, J. Am. Chem. Sec., 105 (1983) 3082), and to two formally doubly excited states, (1)A(1g) [(1)(delta delta,delta*delta*)] and (1)E(u) [(pi delta,delta*delta*)]. C1 LOS ALAMOS NATL LAB,NATL HIGH MAGNET FIELD LAB,LOS ALAMOS,NM 87545. RP Maverick, AW (reprint author), LOUISIANA STATE UNIV,DEPT CHEM,BATON ROUGE,LA 70803, USA. RI Maverick, Andrew/A-3617-2009; Goettee, Jeffrey/L-4926-2015; Butler, Leslie/D-1636-2016 OI Maverick, Andrew/0000-0001-9987-1663; Butler, Leslie/0000-0003-1547-608X NR 24 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD FEB 29 PY 1996 VL 243 IS 1-2 BP 309 EP 316 DI 10.1016/0020-1693(96)04921-3 PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UM713 UT WOS:A1996UM71300039 ER PT J AU Savikhin, S Zhu, YW Blankenship, RE Struve, WS AF Savikhin, S Zhu, YW Blankenship, RE Struve, WS TI Ultrafast energy transfer in chlorosomes from the green photosynthetic bacterium Chloroflexus aurantiacus SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Letter ID ORGANIZATION AB Energy transfers between the bacteriochlorophyll c and a antennae in light-harvesting chlorosomes from the green bacterium Chloroflexus aurantiacus have been studied in two-color pump-probe experiments with improved sensitivity and wavelength versatility. The BChl c --> BChl a energy transfers are well simulated with biexponential kinetics, with lifetimes of 2-3 and 11 ps. They do not exhibit an appreciable subpicosecond component. In the context of a kinetic model for chlorosomes, these lifetimes suggest that both internal BChl c processes and the BChl c --> BChl a energy-transfer step contribute materially to the empirical rod-to-baseplate energy-transfer kinetics. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. ARIZONA STATE UNIV,DEPT CHEM & BIOCHEM,TEMPE,AZ 85287. ARIZONA STATE UNIV,CTR STUDY EARLY EVENTS PHOTOSYNTHESIS,TEMPE,AZ 85287. FU NIDCR NIH HHS [DE-FG-85ER133388] NR 11 TC 35 Z9 35 U1 0 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 29 PY 1996 VL 100 IS 9 BP 3320 EP 3322 DI 10.1021/jp953734k PG 3 WC Chemistry, Physical SC Chemistry GA TX766 UT WOS:A1996TX76600005 PM 11539413 ER PT J AU Chang, YJ Castner, EW AF Chang, YJ Castner, EW TI Intermolecular dynamics of substituted benzene and cyclohexane liquids, studied by femtosecond nonlinear-optical polarization spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Review ID STIMULATED LIGHT-SCATTERING; MOLECULAR VIBRATIONAL MOTION; RAMAN-SPECTROSCOPY; CARBON-DISULFIDE; BINARY-SOLUTIONS; KERR DYNAMICS; GAIN SPECTRA; CS2; PHASE; ACETONITRILE AB Femtosecond time-resolved optical-heterodyne detected Raman-induced Kerr effect spectroscopy (OHD-RIKES) is shown to be a powerful and comprehensive tool for studying the intermolecular dynamics occurring in liquids. The observed dynamics include both the underdamped, or coherent inertial motions, and the longer time scale diffusive relaxation. The inertial dynamics include phonon-like intermolecular vibrations, intermolecular collisions, and librational caging motions. Data are presented and analyzed for a series of five liquids: cyclohexane, methylcyclohexane, toluene, benzyl alcohol, and benzonitrile, listed in order of increasing polarity. We explore the effects of aromaticity (e.g., methylcyclohexane vs. toluene), symmetry reduction (cyclohexane vs methylcyclohexane), and substitution effects (e.g., substituted benzene series) on the ultrafast intermolecular dynamics, for a group of molecular liquids of similar size and volume. We analyze the intermolecular dynamics in both the time and frequency domains by means of Fourier transformations. When Fourier-transformed into the frequency domain, the OHD-RIKES ultrafast transients of the intermolecular dynamics can be directly compared with the frequency domain spectra obtained from the far-infrared absorption and depolarized Raman techniques. This is done using the Gaussian librational caging model of Lynden-Bell and Steele, which results in a power-law scaling relation between dipole and polarizability time correlation functions. Last, we use a theoretical treatment of Maroncelli and co-workers to model for some of these liquids the solvation time-correlation function for the solvation of a charge-transfer excited-state chromophore based on the measured neat solvent dynamics. C1 BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. NR 121 TC 103 Z9 103 U1 1 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 29 PY 1996 VL 100 IS 9 BP 3330 EP 3343 DI 10.1021/jp952073o PG 14 WC Chemistry, Physical SC Chemistry GA TX766 UT WOS:A1996TX76600007 ER PT J AU Scheuring, EM Clavin, W Wirt, MD Miller, LM Fischetti, RF Lu, Y Mahoney, N Xie, AH Wu, JJ Chance, MR AF Scheuring, EM Clavin, W Wirt, MD Miller, LM Fischetti, RF Lu, Y Mahoney, N Xie, AH Wu, JJ Chance, MR TI Time-resolved X-ray absorption spectroscopy of photoreduced base-off Cob(II)alamin compared to the Co(II) species in Clostridium thermoaceticum SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID SQUARE-PLANAR; VITAMIN-B12 COMPLEXES; EDGE SPECTROSCOPY; PHOSPHITE LIGANDS; COORDINATION; CATALYSIS; ELECTROCHEMISTRY; INTERMEDIATE; EQUILIBRIA; EXAFS AB We have made significant improvements in pump-probe time-resolved X-ray absorption spectroscopy that enable us to structurally describe chemical intermediates with short lifetimes. We demonstrate that X-ray preedge data for a 1 mM compound can be acquired with a high signal-to-noise ratio by time-resolved discrimination of fluorescent signals from a 13-element germanium detector. With the utilization of this novel time-multiplexed laser photolysis system coupled to a flow cell, we characterized the structure of the initial photoproduct of five-coordinate base-off Co(III) methylcobalamin. The structure of the primary photoproduct could have included five- or six-coordinate species with water ligation, or a four-coordinate square-planar species. A four-coordinate Co(II) species is expected to be unstable but its biological relevance is highlighted by our recent discovery of a four-coordinate Co(II) species, (existing as the inactive, as isolated, form) in the corrinoid protein of Clostridium thermoaceticum. The X-ray preedge spectra of five- and six-coordinate species have a strong 1s-3d transition at about 10 eV below the edge. In four-coordinate, square-planar species the 1s-3d intensity is significantly reduced, but they show a 1s-4p, peak at about 6 eV below the edge. We used this ''fingerprint'' to monitor the structural change upon photolysis. Since the quantum yield of the base-off species is 0.48, the observed spectrum upon photolysis is a mixture of photoproduct and initial states. The photoproduct of the base-off methylcobalamin shows a substantial decrease in the 1s-3d peak and significant increase in the 1s-4p, peak. This indicates the formation of a four-coordinate species. The four-coordinate species in the free cobalamin is very unstable and can only be detected by time-resolved methods. This indicates a special role for the protein in maintaining an unusual four-coordinate Co(II) corrinoid. C1 YESHIVA UNIV ALBERT EINSTEIN COLL MED,DEPT PHYSIOL & BIOPHYS,BRONX,NY 10461. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,REG CTR TIME RESOLVED SYNCHROTRON SPECT,UPTON,NY 11973. NR 23 TC 20 Z9 20 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 29 PY 1996 VL 100 IS 9 BP 3344 EP 3348 DI 10.1021/jp943066n PG 5 WC Chemistry, Physical SC Chemistry GA TX766 UT WOS:A1996TX76600008 ER PT J AU Rodriguez, JA Kuhn, M Hrbek, J AF Rodriguez, JA Kuhn, M Hrbek, J TI Repulsive interactions between Au and S on Mo(110) and Rh(111): An experimental and theoretical study SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRONIC-PROPERTIES; THERMAL-DESORPTION; SULFUR; SURFACE; ADSORPTION; RU(001); AG; GROWTH; GOLD; W(110) AB The coadsorption of Au and S on Mo(110) and Rh(111) has been examined using thermal desorption mass spectroscopy, photoemission, and ab initio self-consistent-field calculations. On both surfaces, the interactions between Au and S are repulsive. S reduces the adsorption energy of Au. In some cases, the weakening of the Mo-An and Rh-Au bonds is so large (5-7 kcal/mol) that the Au adatoms ''ball up'' on the surface instead of ''wetting'' the Mo(110) and Rh(111) substrates. The ab initio SCF calculations show that a S adatom modifies the chemical behavior of adjacent Mo and Rh sites by reducing their contribution to the density of states around the Fermi level of the system, weakening in this way their ability to form strong bonds with Au. In the Au/S/Mo(110) and Au/S/Rh(111) surfaces, Au and S compete for the electrons of the transition-metal substrate. Gold produces dramatic changes in the reaction pathways for the removal of sulfur from the Mo and Rh surfaces. In the Au/S/Rh(111) system, S-2 desorbs at much lower temperatures (100-250 K) than in S/Rh(111). For Au/S/Mo(110), the presence of Au favors desorption of St instead of migration of S into the bulk of Mo. These results are consistent with a model in which An compresses the S overlayer into islands of high local coverage, reducing in this way its stability and favoring the ''pairing'' of sulfur atoms and desorption of S-2. RP Rodriguez, JA (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Hrbek, Jan/I-1020-2013 NR 60 TC 28 Z9 28 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 29 PY 1996 VL 100 IS 9 BP 3799 EP 3808 DI 10.1021/jp952861d PG 10 WC Chemistry, Physical SC Chemistry GA TX766 UT WOS:A1996TX76600070 ER PT J AU Schmidt-Rohr, K Hong, M AF Schmidt-Rohr, K Hong, M TI Information on bond orientation distributions in lipids and liquid crystals from segmental order parameters SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID PHOSPHATIDYLCHOLINE BILAYERS; MAGNETIC-RESONANCE; HEAD-GROUP; C-13 NMR; CHAINS; CONFORMATION AB The information content of segmental order parameters in liquid-crystalline lipids is analyzed in terms of orientation distributions. First, we discuss the use of segmental order tensors, determined from motionally averaged NMR anisotropies, for obtaining approximations to the orientation distribution of the director in the molecular segment. In addition to the distribution consisting of second-order spherical harmonics, two physically reasonable five-parameter distributions are examined, and the relation of the two shape parameters of these distributions to the principal order parameters is presented. The usefulness of these distributions for the determination of torsional angles is also discussed. Furthermore, we introduce a novel approach for obtaining model-independent limits to bond orientation probabilities from bond order parameters. The analysis shows, for instance, that the C-H bonds of the glycerol sn-3 CH2 group in phosphatidylcholine, with bond order parameters of -0.22, are oriented preferentially at angles between 52 degrees and 128 degrees from the director. The probability that these bonds are oriented at angles smaller than 30 degrees or larger than 150 degrees is less than 25%. Assuming an upper limit to the ruggedness of the distribution, even more stringent probability limits can be given. For instance, using a minimum standard deviation of 10 degrees for any conformation, a C-H order parameter of -0.22 corresponds to a probability of less than 25% for C-H orientations below 51 degrees and above 129 degrees., The approaches described here are generally applicable to uniaxial liquid-crystalline systems. C1 LAWRENCE BERKELEY NATL LAB, DIV MAT SCI, BERKELEY, CA USA. UNIV CALIF BERKELEY, DEPT CHEM, BERKELEY, CA 94720 USA. UNIV MASSACHUSETTS, DEPT POLYMER SCI & ENGN, AMHERST, MA 01003 USA. NR 20 TC 8 Z9 8 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 29 PY 1996 VL 100 IS 9 BP 3861 EP 3867 DI 10.1021/jp952788r PG 7 WC Chemistry, Physical SC Chemistry GA TX766 UT WOS:A1996TX76600078 ER PT J AU Eckert, J Albinati, A Bucher, UE Venanzi, LM AF Eckert, J Albinati, A Bucher, UE Venanzi, LM TI Nature of the Rh-H-2 bond in a dihydrogen complex stabilized only by nitrogen donors. Inelastic neutron scattering study of Tp(Me(2))RhH(2)(eta(2)-H-2) (Tp(Me(2)) equals hydrotris (3,5-dimethylpyrazolyl)borate) SO INORGANIC CHEMISTRY LA English DT Article ID EXTREMELY LOW BARRIER; H-2 LIGAND; ROTATION; HYDROGEN; HYDRIDE AB The tunnel splitting of the librational ground state and the torsional frequencies of the dihydrogen ligand in Tp(Me2)RhH(2)(eta(2)-H-2) (Tp(Me2) = hydrotris(3,5-dimethylpyrazolyl)borate) were measured using inelastic neutron The barrier for the rotation of the H-2 ligand and its H-H separation, calculated from these data, are 0.56(2) kcal/mol and 0.94 Angstrom, respectively. These values indicate that pi-back-donation from the Tp(Me2)RhH(2) fragment to H-2 is relatively weak and/or the interaction between the coordinated dihydrogen molecule and the two cis-hydride ligands significantly lowers the barrier for H-2 rotation. C1 UNIV MILAN,IST CHIM FARMACEUT,I-20131 MILAN,ITALY. ETH ZENTRUM,ANORGAN CHEM LAB,CH-8092 ZURICH,SWITZERLAND. RP Eckert, J (reprint author), LOS ALAMOS NATL LAB,LANSCE,MS H805,LOS ALAMOS,NM 87545, USA. RI Albinati, Alberto/I-1262-2015 OI Albinati, Alberto/0000-0002-8779-3327 NR 17 TC 32 Z9 32 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD FEB 28 PY 1996 VL 35 IS 5 BP 1292 EP 1294 DI 10.1021/ic950452q PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA TY260 UT WOS:A1996TY26000031 ER PT J AU Zhu, ZL AlAjlouni, AM Espenson, JH AF Zhu, ZL AlAjlouni, AM Espenson, JH TI Convenient synthesis of bis(alkoxy)rhenium(VII) complexes SO INORGANIC CHEMISTRY LA English DT Article ID MAIN-GROUP ELEMENTS; TRANSITION-METALS; MULTIPLE BONDS; CATALYST; METHYLTRIOXORHENIUM; OXIDES; OXIDATION AB The title compounds can be conveniently prepared by this reaction, for which a [GRAPHICS] INF>Cl-2 at room temperature results in reduction of the unique carbonyl to a methyl group, giving the ethylidyne cluster (mu-H)(3)Os-3(CO)(9)(mu(3)-CCH3). A single-crystal X-ray structure determination verified the formation of (mu-H)(3)Os-3(CO)(9)(mu(3)-CCH3). No evidence was observed for the formation of intermediate species, such as the vinylidene cluster (mu-H)(2)Os-3-(CO)(9)(mu(3)-eta(2)-C=CH2). Treatment of (mu-H)(2)Os-3-(CO)(9)(mu(3)-eta(2)-C=CH2) with pure, freshly prepared BH3 . THF for 5 days in CH2Cl2 yielded no (mu-H)(3)Os-3-(CO)(9)(mu(3)-CCH3). C1 IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. IOWA STATE UNIV SCI & TECHNOL, DEPT CHEM, AMES, IA 50011 USA. NR 21 TC 45 Z9 45 U1 1 U2 8 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 FEB 28 PY 1996 VL 35 IS 5 BP 1408 EP + DI 10.1021/ic951181m PG 0 WC Chemistry, Inorganic & Nuclear SC Chemistry GA TY260 UT WOS:A1996TY26000055 ER PT J AU Goldbach, A Iton, L Grimsditch, M Saboungi, ML AF Goldbach, A Iton, L Grimsditch, M Saboungi, ML TI The formation of Se-2(-): A new resonance Raman feature in the photochemistry of zeolite-encapsulated selenium SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SPECTRA; CHAINS; MORDENITE; CLUSTERS; CHANNELS AB This Raman spectroscopic study on selenium incorporated in Nd-Y zeolite presents new aspects of the photochemistry of selenium. The formation of the Se-2(-) radical anion has been established from its resonance Raman spectrum, consisting of ten almost equidistant bands between 328 and 3220 cm(-1) on the low-energy side of the 476.24-nm laser excitation line. The derived spectroscopic constants of the electronic ground state are omega(0) = 328 cm(-1) and chi(0) omega(0) = 0.71 cm(-1). Another broad band at 260 cm(-1) resembles features in the Raman spectra of amorphous selenium and selenium chain structures encapsulated in zeolites. Continuous irradiation at sufficiently high laser power levels leads to depletion of the 260 cm(-1) band and a simultaneous enhancement of the Se-2(-) bands. These observations are discussed with respect to the defect states conventionally invoked for reversible photoinduced changes in amorphous selenium. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RI Saboungi, Marie-Louise/C-5920-2013 OI Saboungi, Marie-Louise/0000-0002-0607-4815 NR 24 TC 30 Z9 32 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 28 PY 1996 VL 118 IS 8 BP 2004 EP 2007 DI 10.1021/ja9531788 PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA TX627 UT WOS:A1996TX62700021 ER PT J AU Camaioni, DM Autrey, ST Salinas, TB Franz, JA AF Camaioni, DM Autrey, ST Salinas, TB Franz, JA TI Calculation of the effects of branching and conjugation on intrinsic barriers for H atom transfer reactions involving hydrocarbons SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; BOND-DISSOCIATION-ENERGIES; RADICAL CHAIN-REACTION; INDUCED REDOX REACTION; HYDROGEN-TRANSFER; RATE CONSTANTS; COAL-LIQUEFACTION; TRANSITION-STATE; ABSTRACTION REACTIONS; SEMIEMPIRICAL METHODS AB This paper describes the use of the semiempirical molecular orbital (MO) theoretical methods (AM1 and MNDO-PM3) to calculate barriers for a series of H atom transfer identity reactions involving alkyl, alkenyl, arylalkyl, and hydroaryl systems. Transition state (TS) energies were calculated for a series of known H abstractions and show to correlate linearly with experimental TS energies. Barriers for H abstraction reactions decrease with the degree of alkyl substitution at the radical site, and increase with the degree of conjugation. Barriers for transfer of a beta-hydrogen from a radical to an unsaturated hydrocarbon (radical hydrogen transfer or RHT) were also calculated. The results show that methyl group substitutions at the radical site lower the barrier while substitutions at the site beta to the radical, the position from which the H originates, raise the barrier. The barriers for RHT reactions involving conjugated systems increase with increasing radical delocalization and correlate linearly with the strength of the donor radical beta-C-H bond. RHT barriers are estimated to range from E(a) approximate to 17-20 kcal/mol for benzene-plus-cyclohexadiene to E(a) approximate to 26-29 kcal/mol for anthracene-plus-9-hydroanthracene. RP Camaioni, DM (reprint author), PACIFIC NW NATL LAB,BOX 999,RICHLAND,WA 99352, USA. NR 71 TC 36 Z9 38 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 28 PY 1996 VL 118 IS 8 BP 2013 EP 2022 DI 10.1021/ja950740l PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA TX627 UT WOS:A1996TX62700023 ER PT J AU Bromberg, SE Lian, TQ Bergman, RG Harris, CB AF Bromberg, SE Lian, TQ Bergman, RG Harris, CB TI Ultrafast dynamics of Cp*M(CO)(2) (M=Ir, Rh) in solution: The origin of the low quantum yields for C-H bond activation SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SOLUTION PHOTOCHEMISTRY; CONDENSED PHASE; RECOMBINATION; SPECTROSCOPY; KINETICS AB Using picosecond transient absorption spectroscopy we have examined the dynamics of Cp*Ir(CO)(2)(Cp* = C(5)Me(5)) in cyclohexane and Cp*Rh(CO)(2) in n-pentane solution at room temperature following 295-nm UV excitation. A transient absorption with an instrument limited risetime was observed for Ir from 440 to 740 nm and for Rh from 500 to 650 nm. Each transient can be well fit to a biexponential decay consisting of a fast component of 2-3 ps and a slower component of 30-40 ps. These transients are attributed to excited state absorptions. Taking into account independent femtosecond IR studies of the ground state recovery and our data, we suggest that most excited state molecules relax through nondissociative excited states, decaying to the ground state without the loss of CO. These results offer an explanation for the low C-H bond activation quantum yields observed on preparative irradiation of Cp*Ir(CO)(2) and Cp*Rh(CO)(2). C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI Lian, Tianquan/L-8992-2013 OI Lian, Tianquan/0000-0002-8351-3690 NR 20 TC 39 Z9 39 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 28 PY 1996 VL 118 IS 8 BP 2069 EP 2072 DI 10.1021/ja9531889 PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA TX627 UT WOS:A1996TX62700028 ER PT J AU Clark, DL Conradson, SD Ekberg, SA Hess, NJ Neu, MP Palmer, PD Runde, W Tait, CD AF Clark, DL Conradson, SD Ekberg, SA Hess, NJ Neu, MP Palmer, PD Runde, W Tait, CD TI EXAFS studies of pentavalent neptunium carbonate complexes. Structural elucidation of the principal constituents of neptunium in groundwater environments SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ABSORPTION FINE-STRUCTURE C1 LOS ALAMOS NATL LAB, DIV MAT SCI & TECHNOL, LOS ALAMOS, NM 87545 USA. PACIFIC NW LAB, DIV MAT SCI, RICHLAND, WA 99352 USA. GT SEABORG INST TRANSACTINIUM SCI, LIVERMORE, CA 94551 USA. RP Clark, DL (reprint author), LOS ALAMOS NATL LAB, CHEM SCI & TECHNOL DIV, MAIL STOP G739, LOS ALAMOS, NM 87545 USA. RI Clark, David/A-9729-2011 NR 19 TC 56 Z9 57 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 28 PY 1996 VL 118 IS 8 BP 2089 EP 2090 DI 10.1021/ja9516423 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA TX627 UT WOS:A1996TX62700032 ER PT J AU Syn, CK Lesuer, DR Sherby, OD AF Syn, CK Lesuer, DR Sherby, OD TI Enhancing tensile ductility of a particulate-reinforced aluminum metal matrix composite by lamination with Mg-9%Li alloy SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE tensile ductility; laminated metal composite ID TEMPERATURE; BEHAVIOR AB A laminated metal composite has been made by press bonding alternating layers of a particulate-reinforced aluminum metal matrix composite (MMC), 6090/SiC/25p, and a highly ductile Mg-9%Li alloy. The mechanical properties including tensile ductility were evaluated for the 50-50 volume fraction laminated composite. The tensile yield strength of the composite obeyed the rule of averages in agreement with other laminates based on aluminum and ultrahigh carbon steel. Lamination of the Al MMC material is shown to increase the tensile ductility from 8.0% to 11.5%. The ductility of the laminated composite was found to be limited by interlayer reaction products developed during processing which led to delamination. Thus necking of the MMC Al layers could occur leading to premature failure. C1 STANFORD UNIV,DEPT MAT SCI & ENGN,STANFORD,CA 94305. RP Syn, CK (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 14 TC 22 Z9 23 U1 1 U2 7 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD FEB 28 PY 1996 VL 206 IS 2 BP 201 EP 207 DI 10.1016/0921-5093(95)09995-6 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA UA617 UT WOS:A1996UA61700006 ER PT J AU Wang, JN AF Wang, JN TI Prediction of peierls stresses for different crystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE Peierls stress; crystals; stress ID STACKING-FAULTS; DISLOCATIONS AB It is a long outstanding question whether or not the Peierls stress for a given slip system of a crystal can be quantitatively determined. This paper concerns the prediction of this stress for a wide range of crystals, using a new theoretical Peierls stress equation. It is shown that the prediction is in reasonable agreement with experimental data. Comparison with atomistic calculations illustrates that the accuracy of the prediction may degenerate greatly in the cases where the spreading of the dislocation core is non-planar and the application of an external stress changes the core structure significantly. It is suggested that the magnitude of the Peierls stress is determined primarily by the geometrical configuration of the dislocation core. RP Wang, JN (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-370,LIVERMORE,CA 94551, USA. NR 36 TC 62 Z9 64 U1 0 U2 5 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD FEB 28 PY 1996 VL 206 IS 2 BP 259 EP 269 DI 10.1016/0921-5093(95)09982-4 PG 11 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA UA617 UT WOS:A1996UA61700013 ER PT J AU Baker, EN Blundell, TL Vijayan, M Dodson, E Dodson, G Gilliland, GL Sussman, JL AF Baker, EN Blundell, TL Vijayan, M Dodson, E Dodson, G Gilliland, GL Sussman, JL TI Untitled SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Letter C1 UNIV LONDON BIRKBECK COLL,DEPT CRYSTALLOG,IMPERIAL CANC RES FUND,STRUCT MOLEC BIOL UNIT,LONDON WC1E 7HX,ENGLAND. INDIAN INST SCI,MOLEC BIOPHYS UNIT,BANGALORE 560012,KARNATAKA,INDIA. UNIV YORK,DEPT CHEM,YORK YO1 5DD,N YORKSHIRE,ENGLAND. CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. WEIZMANN INST SCI,DEPT BIOL STRUCT,IL-76100 REHOVOT,ISRAEL. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP Baker, EN (reprint author), MASSEY UNIV,DEPT CHEM & BIOCHEM,PALMERSTON NORTH,NEW ZEALAND. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0006-291X J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD FEB 27 PY 1996 VL 219 IS 3 BP 976 EP 977 DI 10.1006/bbrc.1996.0342 PG 2 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA TZ799 UT WOS:A1996TZ79900050 PM 8645289 ER PT J AU Nowakowski, J Tinoco, I AF Nowakowski, J Tinoco, I TI Conformation of an RNA molecule that models the P4/P6 junction from group I introns SO BIOCHEMISTRY LA English DT Article ID NMR-SPECTROSCOPY; RIBOSOMAL-RNA; 3-DIMENSIONAL MODEL; COUPLING-CONSTANTS; STABILITY; STACKING; CCGG; H-1 AB We present a three-dimensional structure of a 34-nucleotide RNA molecule determined by NMR spectroscopy, The molecule was designed to form a junction between two double-helical stems whose sequence was based on the P4/P6 domain from group I introns. There are 5' and 3' single-strand overhangs at the junction of the stems. Contrary to our expectations, we found that the 3' end of the molecule is placed in the minor and not the major groove of the P4 helix. As a result of tertiary contacts and stacking interactions from nucleotides in the 3' end, the junction helices are rotated in a left-handed fashion and do not stack coaxially. This conformation is highly dependent on the presence of single-stranded nucleotides at the 3' overhang. When the 3' end is removed, the molecule assumes a radically different structure with the 5' end in the minor groove of the P6 helix and an overall right-handed rotation between the stems. Only one nucleotide at the 3' end is sufficient to change the energy of the junction. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. FU NIGMS NIH HHS [GM 10840] NR 32 TC 12 Z9 12 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 27 PY 1996 VL 35 IS 8 BP 2577 EP 2585 DI 10.1021/bi952263p PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TX500 UT WOS:A1996TX50000009 PM 8611561 ER PT J AU Adler, S Atiya, MS Chiang, IH Frank, JS Haggerty, JS Kycia, TF Li, KK Littenberg, LS Sambamurti, A Stevens, A Strand, RC Witzig, C Louis, WC Akerib, DS Ardebili, M Convery, MR Ito, MM Marlow, DR McPherson, RA Meyers, PD Selen, MA Shoemaker, FC Smith, AJS Blackmore, EW Bryman, DA Felawka, L Kitching, P Konaka, A Kujala, VA Kuno, Y Macdonald, JA Nakano, T Numao, T Padley, P Poutissou, JM Poutissou, R Roy, J Soluk, R Turcot, AS AF Adler, S Atiya, MS Chiang, IH Frank, JS Haggerty, JS Kycia, TF Li, KK Littenberg, LS Sambamurti, A Stevens, A Strand, RC Witzig, C Louis, WC Akerib, DS Ardebili, M Convery, MR Ito, MM Marlow, DR McPherson, RA Meyers, PD Selen, MA Shoemaker, FC Smith, AJS Blackmore, EW Bryman, DA Felawka, L Kitching, P Konaka, A Kujala, VA Kuno, Y Macdonald, JA Nakano, T Numao, T Padley, P Poutissou, JM Poutissou, R Roy, J Soluk, R Turcot, AS TI Search for the decay K+->pi(+)nu(nu)over-bar SO PHYSICAL REVIEW LETTERS LA English DT Article ID RARE KAON DECAYS; K+->PI+NU(NU)OVER-BAR; CONSTRAINTS; SYMMETRY AB An upper limit on the branching ratio for the decay K+ --> pi(+) is set at 2.4 x 10(-9) at the 90% C.L. using pions in the kinematic region 214 MeV/c < P-pi < 231 MeV/c. An upper limit of 5.2 x 10(-10) is found on the branching ratio for decays K+ --> pi(+)X(0) where X(O) is any massless, weakly interacting neutral particle. Limits are also set for cases where M(X0) > 0. C1 LOS ALAMOS NATL LAB,MEDIUM ENERGY PHYS DIV,LOS ALAMOS,NM 87545. PRINCETON UNIV,JOSEPH HENRY LABS,PRINCETON,NJ 08544. TRIUMF,VANCOUVER,BC V6T 2A3,CANADA. RP Adler, S (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Marlow, Daniel/C-9132-2014 NR 25 TC 31 Z9 31 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 FEB 26 PY 1996 VL 76 IS 9 BP 1421 EP 1424 DI 10.1103/PhysRevLett.76.1421 PG 4 WC Physics, Multidisciplinary SC Physics GA TW700 UT WOS:A1996TW70000005 ER PT J AU Ding, H Bellman, AF Campuzano, JC Randeria, M Norman, MR Yokoya, T Takahashi, T KatayamaYoshida, H Mochiku, T Kadowaki, K Jennings, G Brivio, GP AF Ding, H Bellman, AF Campuzano, JC Randeria, M Norman, MR Yokoya, T Takahashi, T KatayamaYoshida, H Mochiku, T Kadowaki, K Jennings, G Brivio, GP TI Electronic excitations in Bi2Sr2CaCu2O8: Fermi surface, dispersion, and absence of bilayer splitting SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; SPECTRAL WEIGHT; SUPERCONDUCTORS; YBA2CU3OX AB From a detailed study, including polarization dependence, of the normal state angle-resolved photoemission spectra for Bi2Sr2CaCu2O8, We find only one CuO2 band related feature. All other spectral features can be ascribed either to unklapps from the superlattice or to ''shadow bands.'' Even though the dispersion of the peaks looks like band theory, the line shape is anomalously broad and no evidence is found for bilayer splitting. We argue that the ''dip feature'' in the spectrum below T-c arises not from bilayer splitting, but rather from many-body effects. C1 UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60607. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 980,JAPAN. NATL RES INST MET,TSUKUBA,IBARAKI 305,JAPAN. RP Ding, H (reprint author), ARGONNE NATL LAB,DIV SCI MAT,ARGONNE,IL 60439, USA. RI Takahashi, Takashi/E-5080-2010; Tohoku, Arpes/A-4890-2010; Campuzano, Juan Carlos/G-4358-2012; Norman, Michael/C-3644-2013; YOKOYA, Takayoshi/B-1478-2011; OI Ding, Hong/0000-0003-4422-9248 NR 25 TC 217 Z9 219 U1 1 U2 16 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 FEB 26 PY 1996 VL 76 IS 9 BP 1533 EP 1536 DI 10.1103/PhysRevLett.76.1533 PG 4 WC Physics, Multidisciplinary SC Physics GA TW700 UT WOS:A1996TW70000033 ER PT J AU Hoover, WG Holian, BL AF Hoover, WG Holian, BL TI Kinetic moments method for the canonical ensemble distribution SO PHYSICS LETTERS A LA English DT Article ID ISOTHERMAL MOLECULAR-DYNAMICS; OSCILLATOR; SIMULATIONS AB Simultaneous integral control of the kinetic energy (K) and its fluctuation [K-2] - [K](2) gives an extended phase-space distribution consistent with Gibbs' canonical one. This generalization of the Nose-Hoover approach to thermostatting is the simplest time-reversible scheme to exhibit ergodicity for the one-dimensional harmonic oscillator. It is also applicable to equilibrium and nonequilibrium many-body simulations. C1 LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. LAWRENCE LIVERMORE NATL LAB, DEPT PHYS, LIVERMORE, CA 94551 USA. RP UNIV CALIF DAVIS, DEPT APPL SCI, DAVIS, CA 95616 USA. NR 23 TC 77 Z9 77 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 EI 1873-2429 J9 PHYS LETT A JI Phys. Lett. A PD FEB 26 PY 1996 VL 211 IS 5 BP 253 EP 257 DI 10.1016/0375-9601(95)00973-6 PG 5 WC Physics, Multidisciplinary SC Physics GA TX841 UT WOS:A1996TX84100001 ER PT J AU Kosowsky, A AF Kosowsky, A TI Cosmic microwave background polarization SO ANNALS OF PHYSICS LA English DT Article ID COLD DARK MATTER; GRAVITATIONAL-WAVES; RADIATION; ANISOTROPY; FLUCTUATIONS; PERTURBATIONS; UNIVERSES; NEUTRINOS AB Polarization of the cosmic microwave background, though not yet detected, provides a source of information about cosmological parameters complementary to temperature fluctuations. This paper provides a complete theoretical treatment of polarization fluctuations. After a discussion of the physics of polarization, the Boltzmann equation governing the evolution of the photon density matrix is derived from quantum theory and applied to microwave background fluctuations, resulting in a complete set of transport equations for the Stokes parameters from both scalar and tensor metric perturbations. This approach is equivalent at lowest order in scattering kinematics to classical radiative transfer, and provides a general framework for treating the cosmological evolution of density matrices. The metric perturbations are treated in the physically appealing longitudinal gauge. Expressions for various temperature and polarization correlation functions are derived. Detection prospects and theoretical utility of microwave background polarization are briefly discussed. (C) 1996 Academic Press, Inc. C1 UNIV CHICAGO,ENRICO FERMI INST,DEPT PHYS,CHICAGO,IL 60637. NASA,FERMI NATL ACCELERATOR LAB,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510. NR 82 TC 109 Z9 109 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-4916 J9 ANN PHYS-NEW YORK JI Ann. Phys. PD FEB 25 PY 1996 VL 246 IS 1 BP 49 EP 85 DI 10.1006/aphy.1996.0020 PG 37 WC Physics, Multidisciplinary SC Physics GA TV305 UT WOS:A1996TV30500002 ER PT J AU Evans, RJ Wang, DN Agblevor, FA Chum, HL Baldwin, SD AF Evans, RJ Wang, DN Agblevor, FA Chum, HL Baldwin, SD TI Mass spectrometric studies of the thermal decomposition of carbohydrates using C-13-labeled cellulose and glucose SO CARBOHYDRATE RESEARCH LA English DT Article DE cellulose pyrolysis; glucose pyrolysis; C-13 labeling; molecular beam mass spectrometry; collision-induced dissociation ID PYROLYSIS AB The mechanism of the thermal decomposition of carbohydrates is very important to the development of fuels, fibers, and paper products. To help gain more insight into the pyrolysis chemistry of cellulose, we have carried out experimental studies using Acetobacter xylinum cellulose grown on D-(1-C-13)-glucose medium with incorporation levels of 1-C-13 of 14%, as determined by C-13 NMR analysis. Samples of the labeled cellulose, as well as D-(1-C-13)- and D-(2-C-13)-glucose, were pyrolyzed under fast-heating conditions and the products analyzed by molecular beam mass spectrometry (MBMS). From the labeled cellulose samples, statistically significant levels of enrichment were observed for the pyrolysis products that occur at m/z 110, 114, 126, 144, and 191, but not at m/z 98, 60, or 31. The lack of enrichment in the latter fragments indicates that they do not incorporate C-1. Samples were treated with 0.1% aqueous KOH to favor the formation of glycolaldehyde, but even in this case this major product was not enriched. These results suggest that the m/z 60 ion is an EI fragment ion of levoglucosan, formed by loss of neutral species containing C-1. However, the m/z 191 ion was found to contain two C-1 carbons. Collision-induced dissociation results for this ion suggest that it consists of a formate group. The structure of this ion is proposed to be the protonated formate of levoglucosan at the C-4 position, derived from either a reverse aldol reaction or a +/--Diels-Alder reaction. The (1-C-13)-glucose pyrolysis product distribution is similar to that for (1-C-13)-labeled cellulose. The (2-C-13)-glucose pyrolysis product distribution shows significant contribution from C-2 at the M + 1 peaks of m/z 32, 43, 60, 73, 85, and 97, indicating major incorporations of C-2 in glycolaldehyde in contrast to the lack of incorporation of the C-1 position in this major product. C1 NATL RENEWABLE ENERGY LAB, IND TECHNOL DIV, GOLDEN, CO 80401 USA. PHILIP MORRIS INC, PHILIP MORRIS RES CTR, RICHMOND, VA 23261 USA. NR 20 TC 35 Z9 36 U1 2 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0008-6215 J9 CARBOHYD RES JI Carbohydr. Res. PD FEB 23 PY 1996 VL 281 IS 2 BP 219 EP 235 DI 10.1016/0008-6215(95)00355-X PG 17 WC Biochemistry & Molecular Biology; Chemistry, Applied; Chemistry, Organic SC Biochemistry & Molecular Biology; Chemistry GA TX992 UT WOS:A1996TX99200003 PM 8721146 ER PT J AU Dulay, MT Yan, C Rakestraw, DJ Zare, RN AF Dulay, MT Yan, C Rakestraw, DJ Zare, RN TI Automated capillary electrochromatography: Reliability and reproducibility studies SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE capillary electrochromatography; electrochromatography ID LIQUID-CHROMATOGRAPHY; INNER DIAMETERS; SEPARATION AB The routine application of capillary electrochromatography (CEC) is demonstrated by incorporating 75 mu m I.D. capillaries packed with 3 mu m octadecylsilica (ODS) particles into a commercial CZE instrument. A mixture of several neutral compounds is separated into its components with an average efficiency up to 181 000 plates/m in less than 8 min. Hundreds of consecutive runs are performed over a period of weeks from which it is concluded that the reproducibility of the capacity factors is better than 2% and that CEC separations can be achieved in a reliable and routine manner. C1 STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. SANDIA NATL LABS,LIVERMORE,CA 94551. RI Zare, Richard/A-8410-2009 NR 21 TC 70 Z9 72 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD FEB 23 PY 1996 VL 725 IS 2 BP 361 EP 366 DI 10.1016/0021-9673(95)01000-9 PG 6 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA UB610 UT WOS:A1996UB61000015 PM 8900577 ER PT J AU Sassi, AP Blanch, HW Prausnitz, JM AF Sassi, AP Blanch, HW Prausnitz, JM TI Characterization of size-exclusion effects in highly swollen hydrogels: Correlation and prediction SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article ID CHROMATOGRAPHY; EQUILIBRIUM; MEMBRANES; GELS AB The literature provides several size-exclusion theories to predict solute exclusion by highly swollen hydrogels. Theoretical calculations are compared to the experimental data of Walther et al. (1993) for partitioning of poly(ethylene glycol)s and poly(ethylene oxide)s of various molecular weight into hydrogels made of poly-N-isopropylacrylamide or poly-2-hydroxyethyl methacrylate/dimethylaminoethyl methacrylate. Experimental size-exclusion curves can be correlated almost equally well by theories which characterize the gel as a collection of pores or of fibers; differences between these two theories are important only for partition coefficients near zero or unity. The experimental data of Walther et al. can be predicted best by Schnitzer's uniform pore model. (C) 1996 John Wiley & Sons, Inc. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 25 TC 18 Z9 18 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD FEB 22 PY 1996 VL 59 IS 8 BP 1337 EP 1346 DI 10.1002/(SICI)1097-4628(19960222)59:8<1337::AID-APP18>3.0.CO;2-2 PG 10 WC Polymer Science SC Polymer Science GA TR924 UT WOS:A1996TR92400018 ER PT J AU Timpson, CJ Bignozzi, CA Sullivan, BP Kober, EM Meyer, TJ AF Timpson, CJ Bignozzi, CA Sullivan, BP Kober, EM Meyer, TJ TI Influence of solvent on the spectroscopic properties of cyano complexes of ruthenium(II) SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID LIGAND CHARGE-TRANSFER; TRANSFER EXCITED-STATES; THERMAL ELECTRON-TRANSFER; TRANSITION-METAL COMPLEXES; RESOLVED RESONANCE RAMAN; TRANSFER ABSORPTION-BAND; MIXED-VALENCE COMPLEXES; INTERVALENCE-TRANSFER; ORGANOMETALLIC COMPLEXES; PHOTOPHYSICAL PROPERTIES AB UV-visible spectra, emission spectra, and RU(III/II) reduction potentials have been measured for cis[Ru(bpy)(2)(py)(CN)](+) (bpy is 2,2'-bipyridine; py is pyridine), cis-Ru(bpy)(2)(CN)(2), [Ru(tpy)(CN)(3)](-) (tpy is 2,2': 6',2''-terpyridine), [Ru(bpy)(CN)(4)](2-), and [Ru(MQ(+))(CN)(5)](2-) (MQ(+) is N-methyl-4,4'-bipyridinium cation) in twelve solvents. The shifts in the metal-to-ligand charge transfer (MLCT) absorption (E(abs)) or emission (E(em)) band energies with solvent increase linearly with the number of cyano ligands and correlate well with the Gutmann ''acceptor number'' of the solvent. Intraligand pi --> pi* band energies also correlate with acceptor number, but with only similar to 30% of the shifts for the MLCT bands, The solvent dependence arises through mixing of the pi --> pi* transitions with lower energy MLCT transitions. MLCT absorption and emission spectra are convolutions of overlapping vibronic components, and a Franck-Condon analysis of emission spectral profiles for cis-Ru(bpy)(2)(CN)(2)* has been used to evaluate the energy gap, E(0), and chi'(0.gs), where chi'(0.gs) is the sum of the solvent reorganizational energy for the ground state below the excited state and the inner-sphere reorganizational energy of the low-frequency modes, chi(i,L), is treated classically. Both E(0) and chi'(0.gs) correlate well with acceptor number with Delta E(0)/Delta AN = 44 +/- 2 cm(-1)/AN unit and Delta chi(0.gs)/AN 21 +/- 3 cm(-1)/AN unit if it is assumed that chi(i,L) is solvent independent. From electrochemical measurements and the difference in E(1/2) values for metal oxidation and bpy reduction, Delta Delta G(es)(0)/Delta AN similar or equal to 70 +/- 7 cm(-1)/AN unit with Delta G(es)(0) the free energy of the excited state above the ground state, These correlations show that the energy gap is far more sensitive to solvent than chi(0,gs). Delta chi(0,gs)/Delta AN can also be estimated from the relation Delta Delta G(es)(0)/Delta AN = Delta E(0)/AN + Delta chi'(0,gs)/Delta AN, which gives Delta chi(0,gs)/Delta AN = 26 +/- 7 cm(-1)/AN unit. The solvent reorganizational energy of the excited state above the ground state is chi(0,es). Its variation with acceptor number can be estimated from the relation Delta E(abs)/Delta AN - Delta G(es)(0)/Delta AN = Delta chi(0,es) (=13 +/- 8 cm(-1)/AN) or from Delta E(abs)/Delta AN - Delta E(em)/Delta AN - Delta chi(0,gs)/Delta AN (=14 +/- 8 cm(-1)/AN), if chi(i,L) is solvent independent. These results suggest that chi(0,gs) is more sensitive to solvent than chi(0,es) by as much as a factor of 2. Delta E(em)/Delta AN = 45 +/- 3 cm(-1)/AN unit similar or equal to Delta E(0)/Delta AN = 44 +/- 2 cm(-1)/AN unit, showing that the emission maximum gives accurate information about the solvent dependence of the energy gap. A model is invoked to explain the acceptor number dependence. It is based on electron pair donation from the lone pair on cyanide to individual solvent molecules through donor-acceptor interactions. The model is consistent with variations in v(CN) with acceptor number in cis-[Ru(bpy)(2)(py)(CN)](+) and in E(1/2)(Ru-III/II) for the series of complexes. In this model it is assumed that donor-acceptor interactions are more important in the ground state than in the excited state, consistent with pK(a) measurements, and that they are additive in the number of cyanide ligands. These and I-I-bonding interactions in related ammine complexes perturb the internal electronic structure of the solute with important consequences. One is that chi(0,gs) not equal chi(0,es) although they are commonly assumed to be equal. C1 UNIV N CAROLINA, DEPT CHEM, CHAPEL HILL, NC 27599 USA. UNIV FERRARA, DIPARTMENTO CHIM, I-44100 FERRARA, ITALY. UNIV WYOMING, DEPT CHEM, LARAMIE, WY 82071 USA. LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. OI Bignozzi, Carlo Alberto/0000-0002-7882-3694 NR 88 TC 122 Z9 123 U1 4 U2 24 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 22 PY 1996 VL 100 IS 8 BP 2915 EP 2925 DI 10.1021/jp953179m PG 11 WC Chemistry, Physical SC Chemistry GA TX257 UT WOS:A1996TX25700020 ER PT J AU Feyereisen, MW Feller, D Dixon, DA AF Feyereisen, MW Feller, D Dixon, DA TI Hydrogen bond energy of the water dimer SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; MOLECULAR WAVE-FUNCTIONS; BASIS-SETS; BENCHMARK CALCULATIONS; SYSTEMATIC SEQUENCES; DIATOMIC HYDRIDES; SCF-CI; ABINITIO; SPECTRA; LIMIT AB Large scale air initio molecular orbital calculations on the binding energy of the water dimer have been performed. These calculations extend the previous correlation consistent basis set work to include larger basis sets (up to 574 functions), and core/valence correlation effects have now been included. The present work confirms the earlier estimate of -4.9 kcal/mol as the MP2(FC) basis set limit. Core/valence correlation effects are found to increase the binding energy by similar to 0.05 kcal/mol. The best estimate of the electronic binding energy of the water dimer is -5.0 +/- 0.1 kcal/mol. Correcting this value for zero-point and temperature effects yields the value Delta H(375) = -3.2 +/- 0.1 kcal/mol. This value is within the error limits of the best experimental estimate of -3.6 +/- 0.5 kcal/mol with the calculations favoring the lower end of the experimental energy range. It should be useful to adopt the present estimate in empirical and semiempirical model potentials. C1 PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. DUPONT CO INC, CENT RES & DEV, EXPTL STN, WILMINGTON, DE 19880 USA. RP Feyereisen, MW (reprint author), CRAY RES INC, EAGAN, MN 55121 USA. NR 43 TC 355 Z9 359 U1 4 U2 39 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 22 PY 1996 VL 100 IS 8 BP 2993 EP 2997 DI 10.1021/jp952860l PG 5 WC Chemistry, Physical SC Chemistry GA TX257 UT WOS:A1996TX25700029 ER PT J AU Causgrove, TP Dyer, RB AF Causgrove, TP Dyer, RB TI Picosecond structural dynamics of myoglobin following photolysis of carbon monoxide SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID RESOLVED VIBRATIONAL SPECTROSCOPY; INFRARED-SPECTROSCOPY; HEME-PROTEINS; LIGAND-BINDING; CONFORMATIONAL RELAXATION; GEMINATE RECOMBINATION; SECONDARY STRUCTURE; SPERM WHALE; AMIDE-I; HEMOGLOBIN AB We have used picosecond infrared (IR) transient absorption spectroscopy in the amide I band tp probe the dynamics of protein motion of myoglobin (Mb) following the photolysis of carbon monoxide. The rise time of the deoxy protein conformation is shown to be about 8 ps. The spectrum of amide I changes was also measured at 50 ps after photolysis and found to be similar to static IR difference spectra and to time-resolved IR spectra taken at times longer than 100 ns. By comparing the results obtained here with other picosecond results on photolysis of CO from Mb, we conclude that the majority of changes seen in the amide I spectra are due to global motion on the proximal side of the heme. The time scale for amide I changes are compared to the results of molecular dynamics calculations. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 44 TC 29 Z9 29 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 22 PY 1996 VL 100 IS 8 BP 3273 EP 3277 DI 10.1021/jp952483c PG 5 WC Chemistry, Physical SC Chemistry GA TX257 UT WOS:A1996TX25700069 ER PT J AU Hutcheon, ID AF Hutcheon, ID TI Meteorites - Signs of an early spring SO NATURE LA English DT Editorial Material ID EARLY SOLAR-SYSTEM; CARBONACEOUS CHONDRITES RP Hutcheon, ID (reprint author), LAWRENCE LIVERMORE NATL LAB,ISOTOPE SCI DIV,7000 EAST AVE,LIVERMORE,CA 94551, USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 22 PY 1996 VL 379 IS 6567 BP 676 EP 677 DI 10.1038/379676a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TW567 UT WOS:A1996TW56700024 PM 8602210 ER PT J AU Fowler, JS Volkow, ND Wang, GJ Pappas, N Logan, J MacGregor, R Alexoff, D Shea, C Schlyer, D Wolf, AP Warner, D Zezulkova, I Cilento, R AF Fowler, JS Volkow, ND Wang, GJ Pappas, N Logan, J MacGregor, R Alexoff, D Shea, C Schlyer, D Wolf, AP Warner, D Zezulkova, I Cilento, R TI Inhibition of monoamine oxidase B in the brains of smokers SO NATURE LA English DT Article ID L-DEPRENYL; PARKINSONS-DISEASE; CIGARETTE SMOKERS; TOBACCO-SMOKE; NEUROTOXICITY; STRIATUM; RATS AB THE massive health problem associated with cigarette smoking is exacerbated by the addictive properties of tobacco smoke and the limited success of current approaches to cessation of smoking(1). Yet little is known about the neuropharmacological actions of cigarette smoke that contribute to smoking behaviour, or why smoking is so prevalent in psychiatric disorders(2) and is associated with a decreased risk of Parkinson's disease(3), Here we report that brains of living smokers show a 40% decrease in the level of monoamine oxidase B (MAO B; EC 1.4.3.4) relative to non-smokers or former smokers. MAO B is involved in the breakdown of dopamine, a neurotransmitter implicated in reinforcing and motivating behaviours as well as movement. MAO B inhibition is therefore associated with enhanced activity of dopamine(4), as well as with decreased production of hydrogen peroxide, a source of reactive oxygen species 5, We propose that reduction of MAO B activity may synergize with nicotine to produce the diverse behavioural and epidemiological effects of smoking. C1 SUNY STONY BROOK,DEPT PSYCHIAT,STONY BROOK,NY 11794. RP Fowler, JS (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 31 TC 462 Z9 473 U1 4 U2 18 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 22 PY 1996 VL 379 IS 6567 BP 733 EP 736 DI 10.1038/379733a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TW567 UT WOS:A1996TW56700054 PM 8602220 ER PT J AU Hamilton, BA Frankel, WN Kerrebrock, AW Hawkins, TL FitzHugh, W Kusumi, K Russell, LB Mueller, KL vanBerkel, V Birren, BW Kruglyak, L Lander, ES AF Hamilton, BA Frankel, WN Kerrebrock, AW Hawkins, TL FitzHugh, W Kusumi, K Russell, LB Mueller, KL vanBerkel, V Birren, BW Kruglyak, L Lander, ES TI Disruption of the nuclear hormone receptor ROR alpha in staggerer mice SO NATURE LA English DT Article ID MUTANT MICE; PURKINJE-CELLS; MULTIPLE INNERVATION; CEREBELLAR CORTEX; CLIMBING FIBERS; MOUSE; ABNORMALITIES AB HOMOZYGOUS staggerer (sg) mice show a characteristic severe cerebellar ataxia due to a cell-autonomous defect in the development of Purkinje cells(1,2). These cells show immature morphology, synaptic arrangement, biochemical properties and gene expression, and are reduced in numbers(3-12). In addition, sg heterozygotes show accelerated dendritic atrophy and cell loss(13), suggesting that sg has a role in mature Purkinje cells. Effects of this mutation on cerebellar development have been studied for 25 years, but its molecular basis has remained unknown, We have genetically mapped staggerer to an interval of 160 kilobases on mouse chromosome 9 which was found to contain the gene encoding ROR alpha, a member of the nuclear hormone-receptor superfamily. Staggerer mice were found to carry a deletion within the ROR alpha gene that prevents translation of the ligand-binding homology domain. We propose a model based on these results, in which ROR alpha interacts with the thyroid hormone signalling pathway to induce Purkinje-cell maturation. C1 JACKSON LAB,BAR HARBOR,ME 04609. MIT,DEPT BIOL,CAMBRIDGE,MA 02139. OAK RIDGE NATL LAB,DIV BIOL,OAK RIDGE,TN 37831. RP Hamilton, BA (reprint author), WHITEHEAD INST BIOMED RES,9 CAMBRIDGE CTR,CAMBRIDGE,MA 02142, USA. RI Kusumi, Kenro/J-2626-2012 OI Kusumi, Kenro/0000-0002-1458-4540 NR 30 TC 339 Z9 342 U1 1 U2 7 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD FEB 22 PY 1996 VL 379 IS 6567 BP 736 EP 739 DI 10.1038/379736a0 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TW567 UT WOS:A1996TW56700055 PM 8602221 ER PT J AU Alkofer, R Roberts, CD AF Alkofer, R Roberts, CD TI Calculation of the anomalous gamma pi(*)->pi pi form factor SO PHYSICS LETTERS B LA English DT Article DE Hadron physics F-gamma pi pi pi(s); Dyson-Schwinger equations; effects of quark and gluon confinement; QCD phenomenology; nonperturbative QCD AB The form factor for the anomalous process gamma pi* --> pi pi, F-3 pi (s, t, u), is calculated as a phenomenological application of the QCD Dyson-Schwinger equations. The chiral-limit value dictated by the electromagnetic, anomalous chiral Ward identity, is reproduced, independent of the details of the modelling of the gluon and quark 2-point Schwinger functions. Using a parametrization of the dressed u-d quark 2-point Schwinger function that provides a good description of pion observables F-3 pi(s, t, u) is calculated on a kinematic range that proposed experiments plan to explore. Our result confirms the general trend of other calculations, i.e., a monotonic increase with s at fixed t and u, but is uniformly larger and exhibits a more rapid rise with s. C1 ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. RP Alkofer, R (reprint author), UNIV TUBINGEN,INST THEORET PHYS,MORGENSTELLE 14,D-72076 TUBINGEN,GERMANY. OI Roberts, Craig/0000-0002-2937-1361 NR 26 TC 38 Z9 38 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 22 PY 1996 VL 369 IS 2 BP 101 EP 107 DI 10.1016/0370-2693(95)01517-5 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TX548 UT WOS:A1996TX54800001 ER PT J AU Dighe, AS Dunietz, I Lipkin, HJ Rosner, JL AF Dighe, AS Dunietz, I Lipkin, HJ Rosner, JL TI Angular distributions and lifetime differences in B-s->J/psi phi decays SO PHYSICS LETTERS B LA English DT Article ID CP-VIOLATION; MESON DECAY; BS MESONS; ASYMMETRIES; B->VV; PARITY; MODE AB The strange B meson B-s = <(b)over bar s> and its charge-conjugate <(B)over bar (s)> = are expected to mix with one another in such a way that the mass eigenstates B-s(H) (''heavy'') and B-s(L) (''light'') may have a perceptible lifetime difference of up to 40%, with the CP-even eigenstate being shorter-lived. A simple transversity analysis permits one to separate the CP-even and CP-odd components of B-s --> J/psi phi, and thus to determine the lifetime difference. The utility of a similar analysis for B-0 --> J/psi K-*0 is noted. C1 UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. FERMILAB NATL ACCELERATOR LAB,DIV THEORET PHYS,BATAVIA,IL 60510. ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. WEIZMANN INST SCI,DEPT PARTICLE PHYS,IL-76100 REHOVOT,ISRAEL. RP Dighe, AS (reprint author), UNIV CHICAGO,ENRICO FERMI INST,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 41 TC 171 Z9 170 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 FEB 22 PY 1996 VL 369 IS 2 BP 144 EP 150 DI 10.1016/0370-2693(95)01523-X PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TX548 UT WOS:A1996TX54800007 ER PT J AU Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Cinabro, D Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, S Morrison, RJ Nakanishi, S Nelson, HH Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD AF Bishai, M Fast, J Gerndt, E Hinson, JW Miao, T Miller, DH Modesitt, M Shibata, EI Shipsey, IPJ Wang, PN Gibbons, L Johnson, SD Kwon, Y Roberts, S Thorndike, EH Jessop, CP Lingel, K Marsiske, H Perl, ML Schaffner, SF Wang, R Coan, TE Dominick, J Fadeyev, V Korolkov, I Lambrecht, M Sanghera, S Shelkov, V Stroynowski, R Volobouev, I Wei, G Artuso, M Efimov, A Gao, M Goldberg, M He, D Horwitz, N Kopp, S Moneti, GC Mountain, R Mukhin, Y Playfer, S Skwarnicki, T Stone, S Xing, X Bartelt, J Csorna, SE Jain, V Marka, S Freyberger, A Gibaut, D Kinoshita, K Pomianowski, P Schrenk, S Cinabro, D Barish, B Chadha, M Chan, S Eigen, G Miller, JS OGrady, C Schmidtler, M Urheim, J Weinstein, AJ Wurthwein, F Asner, DM Athanas, M Bliss, DW Brower, WS Masek, G Paar, HP Gronberg, J Korte, CM Kutschke, R Menary, S Morrison, RJ Nakanishi, S Nelson, HH Nelson, TK Qiao, C Richman, JD Roberts, D Ryd, A Tajima, H Witherell, MS Balest, R Cho, K Ford, WT Lohner, M Park, H Rankin, P Roy, J Smith, JG Alexander, JP Bebek, C Berger, BE Berkelman, K Bloom, K Cassel, DG Cho, HA Coffman, DM Crowcroft, DS Dickson, M Drell, PS Dumas, DJ Ehrlich, R Elia, R Gaidarev, P Gittelman, B Gray, SW Hartill, DL Heltsley, BK Jones, CD TI Study of B->psi rho SO PHYSICS LETTERS B LA English DT Article AB We have studied the Cabibbo suppressed and color suppressed two-body decays B to psi rho (psi omega or psi a(1)). Using a data sample of 5.12 million B decays collected with the CLEO II detector we find the 90% confidence level upper limits for branching fractions of B-0 --> psi rho(0) and B-0 --> psi omega to be 2.5 . 10(-4) and 2.7 . 10(-4), respectively. We also update the branching fraction B- --> psi pi(-) to be (5.6 +/- 2.7). 10(-5). C1 UNIV ROCHESTER,ROCHESTER,NY 14627. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. SO METHODIST UNIV,DALLAS,TX 75275. SYRACUSE UNIV,SYRACUSE,NY 13244. VANDERBILT UNIV,NASHVILLE,TN 37235. VIRGINIA POLYTECH INST & STATE UNIV,BLACKSBURG,VA 24061. WAYNE STATE UNIV,DETROIT,MI 48202. CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106. UNIV COLORADO,ITHACA,NY 14853. CORNELL UNIV,ITHACA,NY 14853. UNIV FLORIDA,GAINESVILLE,FL 32611. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV HAWAII MANOA,HONOLULU,HI 96822. UNIV ILLINOIS,CHAMPAIGN,IL 61801. CARLETON UNIV,OTTAWA,ON K1S 5B6,CANADA. MCGILL UNIV,MONTREAL,PQ H3A 2T8,CANADA. ITHACA COLL,ITHACA,NY 14850. UNIV KANSAS,LAWRENCE,KS 66045. UNIV MINNESOTA,MINNEAPOLIS,MN 55455. SUNY ALBANY,ALBANY,NY 12222. OHIO STATE UNIV,COLUMBUS,OH 43210. UNIV OKLAHOMA,NORMAN,OK 73019. BINP,NOVOSIBIRSK 630090,RUSSIA. RP Bishai, M (reprint author), PURDUE UNIV,W LAFAYETTE,IN 47907, USA. RI Schaffner, Stephen/D-1189-2011; Briere, Roy/N-7819-2014 OI Briere, Roy/0000-0001-5229-1039 NR 10 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 22 PY 1996 VL 369 IS 2 BP 186 EP 192 DI 10.1016/0370-2693(95)01585-X PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TX548 UT WOS:A1996TX54800011 ER PT J AU Lukens, WW Smith, MR Andersen, RA AF Lukens, WW Smith, MR Andersen, RA TI A pi-donor spectrochemical series for X in (Me(5)C(5))(2)TiX, and beta-agostic interactions in X=Et and N(Me)Ph SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON-PARAMAGNETIC RESONANCE; MOLECULAR-STRUCTURE; SPIN-RESONANCE; COMPLEXES; NITROGEN; SPECTROSCOPY; DERIVATIVES; REACTIVITY; VANADIUM; METHYL AB The EPR and electronic spectra of d(1)-bent metallocene compounds of the type Cp*(2)TiX, where X is halide, alkoxide, amide, alkyl, or hydride and Cp* = Me(5)C(5), have been studied. Several of these compounds are new, and those with X = N(Me)H and F were characterized by X-ray crystallography. The crystal structure of Cp*2TiN(Me)H showed that the N(Me)H ligand lies on the plane defined by Cp*(centroid)-Ti-Cp*(centroid). This is the sterically most unfavorable conformation but allows maximum Ti-N pi-bonding. The anisotropic frozen solution EPR spectra were analyzed by the method used by Petersen and Dahl for the d(1)-metallocenes, Cp(2)VX(2), which gives g(x), g(y), and g(z). Although the values of g(x) and g(z) are relatively constant throughout the series, the value of g(y) varies with the pi-donor ability of X. The pi-donor series is N(Me)H approximate to NH2 approximate to OMe > OPh approximate to F > N(Me)Ph Cl > Br > I > H. Among the known alkyls, the pi-donor ability was Et > Me > n-Pr approximate to CH(2)CMe(3) > CH2C6H5, which is rationalized, in part, by a beta-agostic interaction in the case of Et. The beta-agostic interaction in Cp*(2)TiEt and in Cp*2TiN(Me)Ph was investigated by variable-temperature EPR spectroscopy giving an enthalpy and entropy for the agostic interaction. For Cp*(2)TiEt the parameters for the agostic interaction are Delta H degrees = -1.93(3) kcal/mol and Delta S degrees = -6.3(2) eu, and for Cp*2TiN(Me)Ph, Delta H degrees = -1.5(1) kcal/mol and Delta S degrees = -7.9(5) eu. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT CHEM,DIV CHEM SCI,BERKELEY,CA 94720. RI Smith, Milton/M-3511-2016 OI Smith, Milton/0000-0002-8036-4503 NR 41 TC 99 Z9 99 U1 4 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 21 PY 1996 VL 118 IS 7 BP 1719 EP 1728 DI 10.1021/ja953272o PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA TW959 UT WOS:A1996TW95900019 ER PT J AU Willner, I Doron, A Katz, E Levi, S Frank, AJ AF Willner, I Doron, A Katz, E Levi, S Frank, AJ TI Reversible associative and dissociative interactions of glucose oxidase with nitrospiropyran monolayers assembled onto gold electrodes: Amperometric transduction of recorded optical signals SO LANGMUIR LA English DT Article ID CROWN ETHERS; AZOBENZENE; MEMBRANES; BINDING; ENZYME AB Photoisomerizable nitrospiropyran monolayers assembled onto Au surfaces provide active electrodes for controlling electrical communication of glucose oxidase, GO, and ferrocene-modified glucose oxidase, Fc-GO, with the electrode interface. A thiolated nitrospiropyran monolayer was assembled onto Au electrodes by treatment with 1-(4-mercaptobutyl)-3,3-dimethyl-6'-nitrospiro[indolin-2,2'-[1-2H]benzopyran] (3). The monolayer undergoes reversible photoisomerization to nitrospiropyran (SP (3)) monolayer state and nitromerocyanine (MRH(+) (4)) monolayer. With ferrocenecarboxylic acid as a diffusional electron mediator, the electrobiocatalyzed oxidation of glucose by GO is inhibited in the presence of the MRH(+)-monolayer electrode as compared to the system that includes the SP-monolayer electrode. The inhibition phenomenon originates from electrostatic binding of GO to the MRH(+)-monolayer electrode that perturbs the interfacial redox process with the diffusional electron mediator, ferrocenecarboxylic acid. The interfacial electron-transfer rate between ferrocenecarboxylic acid and the electrode is 10-fold slower in the presence of the MRH(+)-monolayer electrode and GO as compared to the SP-monolayer electrode and GO. Quartz crystal microbalance analyses and determination of the respective capacity currents reveal electrostatic attraction of GO to the MRH(+)-monolayer electrode. With ferrocene-modified glucose oxidase, Fc-GO, the electrobiocatalyzed oxidation of glucose is enhanced in the presence of the MRH(+)-monolayer electrode as compared to the SP-monolayer electrode. The modified enzyme, Fc-GO, exhibits direct electrical communication with the electrode surface. Electrostatic attraction of Fc-GO to the MRH(+)-monolayer electrode increases the biocatalyst concentration at the electrode surface and facilitates electrochemical oxidation of glucose. Similar results are observed upon organization of the nitrospiropyran monolayer on Au electrodes by a stepwise method that includes covalent linkage of 1-(beta-carboxyethyl)-3,3-dimethyl-6'-nitrospiro[indolin-2,2'-[1-2H]benzopyran] (1) to a cystamine monolayer-modified Au electrode. The reversible photoisomerizable properties of the nitrospiropyran monolayer electrodes allow the cyclic modulation of the electrocatalytic anodic currents in the systems that include GO and Fc-GO as biocatalysts. The assemblies represent systems for the amplification and amperometric transduction of optical signals recorded by monolayer electrodes. They can also serve as a model for mimicking basic functions of the vision process. C1 HEBREW UNIV JERUSALEM,FARKAS CTR LIGHT INDUCED PROC,IL-91904 JERUSALEM,ISRAEL. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. RP Willner, I (reprint author), HEBREW UNIV JERUSALEM,INST CHEM,IL-91904 JERUSALEM,ISRAEL. RI Milton, Ross/J-7164-2012 NR 38 TC 83 Z9 84 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 21 PY 1996 VL 12 IS 4 BP 946 EP 954 DI 10.1021/la9507038 PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TW873 UT WOS:A1996TW87300016 ER PT J AU Tantawi, SG Ruth, RD Vlieks, AE AF Tantawi, SG Ruth, RD Vlieks, AE TI Active radio frequency pulse compression using switched resonant delay lines SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB This paper presents a study and design methodology for enhancing the efficiency of the SLED II rf pulse-compression system [P.B. Wilson, Z.D. Farkas and R.D. Ruth, Linear Accel. Conf., Albuquerque, NM, 1990]. This system employs resonant delay lines as a means of storing rf energy. By making the external quality factor of these lines vary as a function of time, the intrinsic efficiency of the system can reach 100%. However, we demonstrate a considerable increase in efficiency even if the change of the quality factor is limited to a single event in time. During this event, the quality factor of the lines changes from one value to another. The difference between these two values is minimized to simplify the realization of the quality factor switch. We present the system optimum parameters for this case. We also show the extension of this system to two events in time, during which the quality factor of the line changes between three predetermined states. The effects of the losses due to the delay lines and the switch used to change the quality factor are also studied. C1 CAIRO UNIV,ELECT & ELECT COMMUN DEPT,GIZA,EGYPT. RP Tantawi, SG (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 10 TC 19 Z9 20 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 FEB 21 PY 1996 VL 370 IS 2-3 BP 297 EP 302 DI 10.1016/0168-9002(95)00816-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000002 ER PT J AU Raubenheimer, TO Kubo, K AF Raubenheimer, TO Kubo, K TI A technique of measuring and correcting emittance dilutions due to accelerator structure misalignments SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID LINEAR COLLIDERS AB This paper describes a method of reducing the transverse emittance dilution in linear colliders due to transverse wakefields arising from misaligned accelerator structures. The technique is a generalization of the Wake-Free [T.O. Raubenheimer, Nucl. Instr. and Meth. A 306 (1991) 61] correction algorithm. The structure errors are measured locally by varying the bunch charge and/or bunch length and measuring the change in the beam trajectory. The structure errors can then be corrected by varying the trajectory or moving the structures. The results of simulations are presented demonstrating the viability of the technique. C1 KEK,TSUKUBA,IBARAKI 305,JAPAN. RP Raubenheimer, TO (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 19 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 21 PY 1996 VL 370 IS 2-3 BP 303 EP 311 DI 10.1016/0168-9002(95)00686-9 PG 9 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000003 ER PT J AU Burman, RL Daemen, LL AF Burman, RL Daemen, LL TI Water target at the ISIS spallation source: Neutrino and neutron fluxes SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Effects arising from a water target placed in the ISIS spallation facility, used for both neutron and neutrino experiments, are considered. Calculations are presented for the neutrino flux from stopped mu(+) decay, and for the neutron fluxes from the ISIS moderators, for several versions of a water target situated upstream of the ISIS spallation source. Two possible configurations, that enhance the neutrino flux by 39-80% and produce relatively little reduction in neutron flux, are outlined. C1 FORSCHUNGSZENTRUM KARLSRUHE, D-76021 KARLSRUHE, GERMANY. RP LOS ALAMOS NATL LAB, P DIV, POB 1663, LOS ALAMOS, NM 87545 USA. RI Lujan Center, LANL/G-4896-2012 NR 11 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 EI 1872-9576 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 21 PY 1996 VL 370 IS 2-3 BP 335 EP 340 DI 10.1016/0168-9002(95)00834-9 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000009 ER PT J AU Vavra, J Kadyk, J Wise, J Coyle, P AF Vavra, J Kadyk, J Wise, J Coyle, P TI Study of photosensitive mixtures of TMAE and helium, hydrocarbon or CF4-based carrier gases SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID TEA AB Among the photocathodes used for particle identification based on the Cherenkov Ring Imaging technique, the TMAE molecule is still the best in terms of quantum efficiency. Despite the fact that TMAE gaseous photocathodes have already been used in a number of large experiments, one still seeks answers to many detailed questions. We present a systematic study of gaseous photocathodes based on TMAE mixed with helium, hydrocarbon and CF4-based gases at normal pressure. The study includes a measurement of the electron drift velocity, gas quenching properties, single electron pulse height spectra and anode wire aging. The paper makes recommendations for carrier gas mixtures to obtain the best quenching, and suggests how to manage TMAE wire aging. This study was motivated by a specific particle identification detector proposal, the Fast Drift GRID proposed for the B-factory at SLAG. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. FAC SCI LUMINY,CNRS,CTR PHYS PARTICULES,F-13288 MARSEILLE,FRANCE. RP Vavra, J (reprint author), STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309, USA. NR 28 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 21 PY 1996 VL 370 IS 2-3 BP 352 EP 366 DI 10.1016/0168-9002(95)00842-X PG 15 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000012 ER PT J AU Rehm, KE Jiang, CL Paul, M Blumenthal, D Gehring, J Henderson, D Nickles, J Nolen, J Pardo, RC Roberts, AD Schiffer, JP Segel, RE AF Rehm, KE Jiang, CL Paul, M Blumenthal, D Gehring, J Henderson, D Nickles, J Nolen, J Pardo, RC Roberts, AD Schiffer, JP Segel, RE TI The use of a gas-filled-magnet in experiments with radioactive ion beams SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID SEPARATION AB A detection system has been developed for experiments with radioactive beams which have considerable contamination from a stable isobar. The system uses the gas-filled magnet technique and identifies reaction products according to nuclear charge and mass with good resolution even at energies below 1 MeV/u. In a first experiment the device has been used to measure cross sections for the F-18(p, alpha)O-15 reaction in the energy range between 650 and 840 keV/u. C1 HEBREW UNIV JERUSALEM,JERUSALEM,ISRAEL. UNIV WISCONSIN,MADISON,WI. NORTHWESTERN UNIV,EVANSTON,IL. RP Rehm, KE (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 24 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 21 PY 1996 VL 370 IS 2-3 BP 438 EP 444 DI 10.1016/0168-9002(95)00825-X PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000024 ER PT J AU Hanlon, JA Ziock, HJ AF Hanlon, JA Ziock, HJ TI Design equations for silicon detector ladders with heat generated by radiation damage induced leakage current SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB We find approximate analytical solutions to the problem of cooling a silicon detector ladder which is internally heated by leakage current caused by radiation damage. The heat generation term has an approximately exponential temperature dependence. Heat is removed by convection and/or conduction to a heat sink. Design equations are derived which prevent thermal runaway, and a wide range of parameter space for those equations is explored. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 7 TC 2 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 FEB 21 PY 1996 VL 370 IS 2-3 BP 521 EP 531 DI 10.1016/0168-9002(95)00797-0 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000035 ER PT J AU Ahmad, I Austin, SM Back, BB Betts, RR Calaprice, FP Chan, KC Chishti, A Chowdhury, P Conner, C Dunford, RW Fox, JD Freedman, SJ Freer, M Gazes, SB Greenberg, JS Greene, JP Hallin, AL Happ, T Henderson, D Kaloskamis, NI Kashy, E Kutschera, W Last, J Lister, CJ Liu, M Maier, MR Mercer, DM Mikolas, D Perera, PAA Rhein, MD Roa, DE Schiffer, JP Trainor, TA Wilt, P Winfield, JS Wolanski, M Wolfs, FLH Wuosmaa, AH Xu, G Young, AR Yurkon, JE AF Ahmad, I Austin, SM Back, BB Betts, RR Calaprice, FP Chan, KC Chishti, A Chowdhury, P Conner, C Dunford, RW Fox, JD Freedman, SJ Freer, M Gazes, SB Greenberg, JS Greene, JP Hallin, AL Happ, T Henderson, D Kaloskamis, NI Kashy, E Kutschera, W Last, J Lister, CJ Liu, M Maier, MR Mercer, DM Mikolas, D Perera, PAA Rhein, MD Roa, DE Schiffer, JP Trainor, TA Wilt, P Winfield, JS Wolanski, M Wolfs, FLH Wuosmaa, AH Xu, G Young, AR Yurkon, JE TI A solenoidal spectrometer for positron electron pairs produced in heavy-ion collisions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID COULOMB BARRIER; TH COLLISIONS; DETECTOR; SPECTROSCOPY; EMISSION; SPECTRA; SYSTEMS; LINES; PEAKS AB A new solenoidal spectrometer, designed to study the production mechanism of electrons and positrons in heavy-ion collisions, has been constructed at Argonne National Laboratory. The spectrometer uses a 300 G magnetic field to transport the leptons to two highly segmented silicon arrays that are centered on the solenoid axis, 1.2 m from the target. Positrons are identified by detecting their annihilation radiation with two arrays of position sensitive NaI(Tl) crystals that surround the silicon arrays. A novel design feature of the spectrometer is the ability to measure the angles of emission of the leptons relative to the solenoid axis. The measured response of the apparatus to electrons and positrons is in very good agreement with the calculated response obtained from Monte Carlo simulations. C1 UNIV ROCHESTER,NUCL STRUCT RES LAB,ROCHESTER,NY 14627. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824. MICHIGAN STATE UNIV,NSCL,E LANSING,MI 48824. UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60607. PRINCETON UNIV,DEPT PHYS,PRINCETON,NJ 08544. YALE UNIV,WRIGHT NUCL STRUCT LAB,NEW HAVEN,CT 06511. FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637. QUEENS UNIV,DEPT PHYS,KINGSTON,ON K7L 3N6,CANADA. GESELL SCHWERIONENFORSCH MBH,W-6100 DARMSTADT,GERMANY. UNIV WASHINGTON,NUCL PHYS LAB,SEATTLE,WA 98195. RI Hallin, Aksel/H-5881-2011; Freer, Martin/F-9379-2013 NR 27 TC 10 Z9 10 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 FEB 21 PY 1996 VL 370 IS 2-3 BP 539 EP 557 DI 10.1016/0168-9002(95)00829-2 PG 19 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UC920 UT WOS:A1996UC92000037 ER PT J AU Wegner, PJ Feit, MD AF Wegner, PJ Feit, MD TI High-power narrow-band pulses with wavelengths tunable about 1.053 mu m from a synchronously pumped optical parametric oscillator SO APPLIED OPTICS LA English DT Article ID BETA-BARIUM BORATE; ALL-SOLID-STATE; 2ND-HARMONIC GENERATION; PICOSECOND; LASER; CRYSTAL; LIB3O5; KTP AB We have constructed an optical parametric oscillator to generate 75-ps near-transform-limited pulses with wavelengths tunable about 1.053 mu m for use in pump-probe studies of self-focusing. The singly resonant oscillator uses a Brewster-cut LiB3O5 crystal that is oriented for type-II phase matching and synchronously pumped by the amplified and frequency-tripled pulse trains from a mode-locked and Q-switched Nd:YLF laser. An intracavity Pockels cell is used to switch out single 0.5-MW pulses at rates of 1 to 10 Hz. The design, construction, and performance of the oscillator are discussed. Measured performance is compared with design predictions and with detailed numerical simulations. (C) 1996 Optical Society of America RP Wegner, PJ (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-444,LIVERMORE,CA 94550, USA. RI Feit, Michael/A-4480-2009 NR 42 TC 1 Z9 1 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD FEB 20 PY 1996 VL 35 IS 6 BP 890 EP 902 DI 10.1364/AO.35.000890 PG 13 WC Optics SC Optics GA TY059 UT WOS:A1996TY05900003 PM 21069085 ER PT J AU Ogihara, NL Parge, HE Hart, PJ Weiss, MS Goto, JJ Crane, BR Tsang, J Slater, K Roe, JA Valentine, JS Eisenberg, D Tainer, JA AF Ogihara, NL Parge, HE Hart, PJ Weiss, MS Goto, JJ Crane, BR Tsang, J Slater, K Roe, JA Valentine, JS Eisenberg, D Tainer, JA TI Unusual trigonal-planar copper configuration revealed in the atomic structure of yeast copper-zinc superoxide dismutase SO BIOCHEMISTRY LA English DT Article ID SUBSTITUTED DERIVATIVES; PULSE-RADIOLYSIS; MECHANISM; RESONANCE AB The three-dimensional structure of yeast copper-zinc superoxide dismutase (CuZnSOD) has been determined in a new crystal form in space group R32 and refined against X-ray diffraction data using difference Fourier and restrained crystallographic refinement techniques, The unexpected result is that the copper ion has moved approximately 1 Angstrom from its position in previously reported CuZnSOD models, the copper-imidazolate bridge is broken, and a roughly trigonal planar ligand geometry characteristic of Cu-I rather than Cu-II is revealed. Final R values for the two nearly identical room temperature structures are 18.6% for all 19 149 reflections in the 10.0-1.7 Angstrom resolution range and 18.2% for 17 682 reflections (F > 2 sigma) in the 10.0-1.73 Angstrom resolution range. A third structure has been determined using X-ray data collected at -180 degrees C. The final R value for this structure is 19.0% (R(free) = 22.9%) for all 24 356 reflections in the 10.0-1.55 Angstrom resolution range, Virtually no change in the positions of the ligands to the zinc center is observed in these models. The origin of the broken bridge and altered Cu-ligand geometry is discussed. C1 UNIV CALIF LOS ANGELES, DEPT CHEM & BIOCHEM, LOS ANGELES, CA 90095 USA. UNIV CALIF LOS ANGELES, US DOE, LAB STRUCT BIOL & MOLEC MED, LOS ANGELES, CA 90095 USA. Scripps Res Inst, RES INST, DEPT MOLEC BIOL, LA JOLLA, CA 92037 USA. LOYOLA MARYMOUNT UNIV, DEPT CHEM & BIOCHEM, LOS ANGELES, CA 90045 USA. RI Valentine, Joan/B-6665-2008; Weiss, Manfred/B-6857-2013 OI Valentine, Joan/0000-0002-7174-925X; FU NIGMS NIH HHS [GM-28222, GM-31229, GM-39346] NR 30 TC 85 Z9 87 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 20 PY 1996 VL 35 IS 7 BP 2316 EP 2321 DI 10.1021/bi951930b PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TW345 UT WOS:A1996TW34500028 PM 8652572 ER PT J AU Bryce, AL Clark, SB AF Bryce, AL Clark, SB TI Nickel desorption kinetics from hydrous ferric oxide in the presence of EDTA SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article; Proceedings Paper CT Symposium on Colloidal and Interfacial Phenomena to Aquatic Environments, at the 209th National Meeting of the American-Chemical-Society CY APR 04-06, 1995 CL ANAHEIM, CA SP Amer Chem Soc, Div Environm Chem DE desorption; dissolution; iron; nickel; remediation ID CHELATING-AGENTS; COORDINATION CHEMISTRY; DISSOLUTION; ADSORPTION; DELTA-AL2O3; HEMATITE; LIGANDS; CADMIUM AB Introducing 10 mu M EDTA to a system of nickel adsorbed to hydrous ferric oxide (HFO) at pH 8 promoted desorption of Ni as well as dissolution of HFO. By monitoring changes in the solution concentrations of Ni and Fe after the introduction of EDTA, it was possible to discern the important processes controlling Ni desorption. This study focused on the effect of the Ni concentration while all other variables were held constant. Under these conditions, Ni desorption and HFO dissolution occurred over two time domains. The first time domain was short (<0.25 h), where desorption and dissolution were fast parallel processes. In the second time domain (>0.25 h), Ni desorption was slower and the solution Fe concentration did not increase measurably over an 8h period. The rates of the observed processes were dependent on the Ni surface concentration, and were attributed to weakly bound surface species in the first time domain, and involved more strongly bound surface species in the second time domain. In the first time domain, increases in the surface concentration increased the Ni desorption rate and decreased the HFO dissolution rate for all surface concentrations studied. The Ni desorption rate in the second time domains also increased linearly with Ni surface concentration, but at surface concentrations >3.2mmol Ni per mol Fe the Ni desorption rate began to approach a maximum value. At total Ni concentrations greater than or equal to 40 mu M, decreases in the solution Fe concentration were observed in the second time domain, and was attributed to metal exchange. This process may become rate limiting at long equilibration times. C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NR 26 TC 10 Z9 10 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD FEB 20 PY 1996 VL 107 BP 123 EP 130 DI 10.1016/0927-7757(95)03350-5 PG 8 WC Chemistry, Physical SC Chemistry GA TW021 UT WOS:A1996TW02100008 ER PT J AU Cheney, MA Sposito, G McGrath, AE Criddle, RS AF Cheney, MA Sposito, G McGrath, AE Criddle, RS TI Abiotic degradation of 2,4-D (dichlorophenoxyacetic acid) on synthetic birnessite: A calorespirometric method SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article; Proceedings Paper CT Symposium on Colloidal and Interfacial Phenomena to Aquatic Environments, at the 209th National Meeting of the American-Chemical-Society CY APR 04-06, 1995 CL ANAHEIM, CA SP Amer Chem Soc, Div Environm Chem DE abiotic degradation; adsorption; birnessite; calorespirometry; dichlorophenoxyacetic acid; diethyl ether; organochlorine herbicides; pollutant breakdown ID SOIL; IDENTIFICATION; MCPA AB Abiotic transformation of organic pollutants in soil environments can contribute significantly to remediation. As a model for the examination of abiotic remediation, the birnessite-catalyzed degradation of 2,4-D(dichlorophenoxyacetic acid) and ethyl ether was monitored by calorespirometric methods, and the products were examined by calorespirometry, chromatography and electron spin resonance (ESR) spectral analysis. Birnessite is a common component of many soils. Birnessite (modeled as the oxide mineral delta-MnO2) is an efficient solid-state catalyst of the breakdown of organic pollutants. Our results show that 2,4-D and ethyl ether adsorbed on the surface of birnessite are rapidly oxidized. Both compounds produce CO2 as a major product, but by somewhat different mechanisms. Analysis of the reaction products by high-performance liquid chromatography shows no accumulation of intermediates. Following reaction with 2,4-D, but not with ethyl ether, ESR analysis detected Mn2+ extractable into methanol. These experiments show (a) that birnessite catalyzes the breakdown of organochlorine herbicides, such as 2,4-D and organic solvents, such as ethyl ether; (b) that CO2 is a major product of degradation for both compounds; (c) that the reaction proceeds via the birnessite-catalyzed oxidation of hydrocarbon structures, but the 54-D-assisted dissolution of birnessite to produce Mn2+ is also involved in the degradation of organic solvents; and (d) that solid-state analysis by calorespirometry allows simple, rapid determinations of the reaction kinetics of pollutant breakdown. C1 UNIV CALIF BERKELEY,DEPT ENVIRONM SCI POLICY & MANAGEMENT,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. UNIV CALIF DAVIS,SECT MOLEC & CELLULAR BIOL,DAVIS,CA 95616. NR 24 TC 25 Z9 25 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD FEB 20 PY 1996 VL 107 BP 131 EP 140 DI 10.1016/0927-7757(95)03385-8 PG 10 WC Chemistry, Physical SC Chemistry GA TW021 UT WOS:A1996TW02100009 ER PT J AU Kopidakis, G Soukoulis, CM Economou, EN AF Kopidakis, G Soukoulis, CM Economou, EN TI Localization and electron-phonon interactions in disordered systems SO EUROPHYSICS LETTERS LA English DT Article ID FRACTAL CHARACTER; POLARON FORMATION; WAVE-FUNCTIONS AB We study numerically the time evolution of the coupled system of an electron, described by a tight-binding model exhibiting metal-insulator transition, interacting with vibrational degrees of freedom. Depending on the initial energy of the electron, E(e)(0), its effective mass, m*, on how close to the mobility edge it is and the strength of the electron-phonon coupling, different types of localized and extended states are formed. We find, that, in general, an increase of E(e)(0) decreases the ability of the system to form localized states, a large m* does not always favor localization and polaron formation is facilitated near the mobility edge. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RES CTR CRETE,FDN RES & TECHNOL HELLAS,GR-71110 IRAKLION,CRETE,GREECE. RP Kopidakis, G (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Economou, Eleftherios /E-6374-2010; Soukoulis, Costas/A-5295-2008 NR 25 TC 7 Z9 7 U1 0 U2 3 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD FEB 20 PY 1996 VL 33 IS 6 BP 459 EP 464 DI 10.1209/epl/i1996-00362-7 PG 6 WC Physics, Multidisciplinary SC Physics GA TY337 UT WOS:A1996TY33700008 ER PT J AU Chen, JB Daniels, LM Angelici, RJ AF Chen, JB Daniels, LM Angelici, RJ TI Unexpected reactions of 2,5-dimethylthiophene (2,5-Me(2)T) in Cp*Ir(eta(5)-2,5-Me(2)T)(2+), Cp*Ir(eta(4)-2,5-Me(2)T), and Cp*Ir(C,S-2,5-Me(2)T) with cobaltocene SO ORGANOMETALLICS LA English DT Article ID OLEFIN IRIDIUM COMPLEXES; SULFUR BOND-CLEAVAGE; 3 METAL CENTERS; COORDINATED THIOPHENE; CRYSTAL-STRUCTURE; BASE HYDROLYSIS; IRON CARBONYLS; HYDRODESULFURIZATION; CP-STAR-IR(2,5-DIMETHYLTHIOPHENE); DESULFURIZATION AB The reaction of Cp*Ir(eta(5)-2,5-Me(2)T)(2+) (1) (Cp* = eta(5)-C(5)Me(5)) with the reducing agent Cp(2)Co yields Cp*Ir(eta(4)-2,5-Me(2)T) (2) and Cp*Ir(C,S-2,5Me(2)T) (3), as well as the unexpected Cp*Ir-(eta(4)-2,5-Me(2)T . C5H4) (4), which can also be prepared by reacting 1 with Cp(-). An X-ray diffraction study of 4 shows the eta(4)-2,5Me(2)T . C5H4 ligand to be a ring-opened 2,5-Me(2)T allyl thiolate conjugated to a cyclopentadienylidene unit. The reduced products 2 and 3 react with Cp(2)Co to give a ferrole-type product Cp*[IrC(Me)=CHCH=C(Me)]CoCp in which the planar iridacyclopentadiene ring is pi-bonded to the cobalt, as established by a structural investigation. The Cp*Co analog of 5 is prepared by the reaction of 2 or 3 with Cp*Co-(CH2=CH2)(2). These studies demonstrate that cobaltocene and Cp*Co(CH2=CH2)(2) readily desulfurize the 2,5-dimethylthiophene ligand in 2 and 3, which supports a previously proposed mechanism for thiophene hydrodesulfurization. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. RP Chen, JB (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011, USA. NR 47 TC 17 Z9 17 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD FEB 20 PY 1996 VL 15 IS 4 BP 1223 EP 1229 DI 10.1021/om9505625 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA TW574 UT WOS:A1996TW57400023 ER PT J AU Willardson, BM Wilkins, JF Yoshida, T Bitensky, MW AF Willardson, BM Wilkins, JF Yoshida, T Bitensky, MW TI Regulation of phosducin phosphorylation in retinal rods by Ca2+/calmodulin-dependent adenylylcyclase SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE visual signal transduction; G protein; cAMP-dependent protein kinase; light adaptation ID OUTER SEGMENTS; FREE CALCIUM; GUANYLATE-CYCLASE; LIGHT; CALMODULIN; PROTEIN; DOMAINS; PHOTORECEPTORS; TRANSDUCIN; ADAPTATION AB The phosphoprotein phosducin (Pd) regulates many guanine nucleotide binding protein (G protein)-linked signaling pathways. In visual signal transduction, unphosphorylated Pd blocks the interaction of light-activated rhodopsin with its G protein (G(t)) by binding to the beta gamma subunits of G(t) and preventing their association with the G(t) alpha subunit. When Pd is phosphorylated by cAMP-dependent protein kinase, it no longer inhibits G(t) subunit interactions. Thus, factors that determine the phosphorylation state of Pd in rod outer segments are important in controlling the number of G(t)s available for activation by rhodopsin. The cyclic nucleotide dependencies of the rate of Pd phosphorylation by endogenous cAMP-dependent protein kinase suggest that cAMP, and not cGMP, controls Pd phosphorylation. The synthesis of cAMP by adenylyl cyclase in rod outer segment preparations was found to be dependent on Ca2+ and calmodulin. The Ca2+ dependence was within the physiological range of Ca2+ concentrations in rods (K-1/2 = 230 +/- 9 nM) and was highly cooperative (n(app) = 3.6 +/- 0.5). Through its effect on adenylyl cyclase and cAMP-dependent protein kinase, physiologically high Ca2+ (1100 nM) was found to increase the rate of Pd phosphorylation 3-fold compared to the rate of phosphorylation at physiologically low Ca2+ (8 nM). No evidence for Pd phosphorylation by other Ca2+-dependent kinases was found. These results suggest that Ca2+ can regulate the light response at the level of G(t) activation through its effect on the phosphorylation state of Pd. C1 LOS ALAMOS NATL LAB,DIV PHYS,BIOPHYS GRP,LOS ALAMOS,NM 87545. RI Wilkins, Jon/A-4984-2009 OI Wilkins, Jon/0000-0001-6405-6538 FU NEI NIH HHS [EY06816] NR 37 TC 57 Z9 60 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD FEB 20 PY 1996 VL 93 IS 4 BP 1475 EP 1479 DI 10.1073/pnas.93.4.1475 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TW698 UT WOS:A1996TW69800023 PM 8643657 ER PT J AU Deri, RJ Emanuel, MA Patterson, FG Dijaili, SP Nguyen, LT AF Deri, RJ Emanuel, MA Patterson, FG Dijaili, SP Nguyen, LT TI Polarization-insensitive wavelength filters by birefringence compensation of vertical couplers SO APPLIED PHYSICS LETTERS LA English DT Article AB We demonstrate a novel birefringence compensation technique to reduce the polarization dependence of AlGaAs directional coupler wavelength filters operating in the 770 to 970 nm wavelength range. By using a multiple quantum well structure to compensate intrinsic waveguide birefringence, we fabricated vertical coupler filters with polarization-dependent wavelength shifts from 0.1 to 2 nm, significantly less than those achieved for conventional devices. Experimental results show that both the filter wavelength and insertion loss can be rendered polarization insensitive by this technique. (C) 1996 American Institute of Physics. RP Deri, RJ (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 13 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 19 PY 1996 VL 68 IS 8 BP 1037 EP 1039 DI 10.1063/1.116240 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500003 ER PT J AU Jia, QX Song, SG Wu, XD Cho, JH Foltyn, SR Findikoglu, AT Smith, JL AF Jia, QX Song, SG Wu, XD Cho, JH Foltyn, SR Findikoglu, AT Smith, JL TI Epitaxial growth of highly conductive RuO2 thin films on (100) Si SO APPLIED PHYSICS LETTERS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; RUTHENIUM DIOXIDE; FATIGUE AB Conductive RuO2 thin films have been heteroepitaxially grown by pulsed laser deposition on Si substrates with yttria-stabilized zirconia (YSZ) buffer layers. The RuO2 thin films deposited under optimized processing conditions are a-axis oriented normal to the Si substrate surface with a high degree of in-plane alignment with the major axes of the (100) Si substrate. Cross-sectional transmission electron microscopy analysis on the RuO2/YSZ/Si multilayer shows an atomically sharp interface between the RuO2 and the YSZ. Electrical measurements show that the crystalline RuO2 thin films are metallic over a temperature range from 4.2 to 300 K and are highly conductive with a room-temperature resistivity of 37+/-2 mu Omega cm. The residual resistance ratio (R(300 K)/R(4.2 K)) above 5 for our RuO2 thin films is the highest ever reported for such films on Si substrates. (C) 1996 American Institute of Physics. C1 LOS ALAMOS NATL LAB,MST5,LOS ALAMOS,NM 87545. RP Jia, QX (reprint author), LOS ALAMOS NATL LAB,SUPERCONDUCT TECHNOL CTR,LOS ALAMOS,NM 87545, USA. RI Jia, Q. X./C-5194-2008 NR 19 TC 50 Z9 51 U1 1 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 19 PY 1996 VL 68 IS 8 BP 1069 EP 1071 DI 10.1063/1.115715 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500014 ER PT J AU Morton, R Lau, SS Poker, DB Chu, PK AF Morton, R Lau, SS Poker, DB Chu, PK TI Coimplantation of carbon and group II acceptors in GaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; AS+ DUAL IMPLANTS; DIFFUSION; MG+; ZN AB Coimplantation of carbon and one of the group II accepters Mg, Zn, or Cd, was performed in GaAs using doses of 5 x 10(14) cm(-2), and the resulting p-type electrical activity was studied. Carbon and group II coimplantation offers a means of maintaining the III-V stoichiometry, which is known to be beneficial for both carbon and group II activation. The group II implantation profiles show reduced diffusivity from the balance in stoichiometry the carbon coimplantation provides. The group II elements Zn and Cd create substantial implantation damage and therefore help assist carbon activation by supplying the necessary abundance of As vacancies. The Mg coimplantation, because of the light mass of the ion, does not create a significant amount of lattice damage at this dose and consequently the implanted carbon remains inactive, which results in reduced conductivity. This investigation differs from past group III and carbon coimplantation studies because both of the coimplanted species, the group II and carbon, contribute to p-type conductivity as well as help to maintain the stoichiometry. (C) 1996 American Institute of Physics. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. CITY UNIV HONG KONG,DEPT PHYS & MAT SCI,HONG KONG,HONG KONG. RP Morton, R (reprint author), UNIV CALIF SAN DIEGO,DEPT ELECT & COMP ENGN,LA JOLLA,CA 92093, USA. RI Chu, Paul/B-5923-2013 OI Chu, Paul/0000-0002-5581-4883 NR 16 TC 4 Z9 4 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 19 PY 1996 VL 68 IS 8 BP 1135 EP 1137 DI 10.1063/1.115737 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500036 ER PT J AU Zhu, Q Botchkarev, A Kim, W Aktas, O Salvador, A Sverdlov, B Morkoc, H Tsen, SCY Smith, DJ AF Zhu, Q Botchkarev, A Kim, W Aktas, O Salvador, A Sverdlov, B Morkoc, H Tsen, SCY Smith, DJ TI Structural properties of GaN films grown on sapphire by molecular beam epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article AB The structural characteristics of GaN films grown on sapphire substrates by molecular beam epitaxy have been investigated using high-resolution synchrotron x-ray diffraction and electron microscopy. We find remarkable correspondence between the in-plane structural order (coherence length and mosaic spread) and the electrical and optical properties. Contrary to common belief, our observations show unequivocally that the out-of-plane structural features, which are considerably better developed than the in-plane counterparts, cannot be used for determining the material quality with respect to their optical and electrical activity. In particular, the (001) mosaic spread is not a good indicator of film quality. (C) 1996 American Institute of Physics. C1 UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61801. UNIV ILLINOIS,COORDINATED SCI LAB,URBANA,IL 61801. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. ARIZONA STATE UNIV,CTR SOLID STATE SCI,TEMPE,AZ 85287. RP Zhu, Q (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 15 TC 40 Z9 40 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 19 PY 1996 VL 68 IS 8 BP 1141 EP 1143 DI 10.1063/1.115739 PG 3 WC Physics, Applied SC Physics GA TV845 UT WOS:A1996TV84500038 ER PT J AU Hlohowskyj, I Brody, MS Lackey, RT AF Hlohowskyj, I Brody, MS Lackey, RT TI Methods for assessing the vulnerability of African fisheries resources to climate change SO CLIMATE RESEARCH LA English DT Article; Proceedings Paper CT Workshop on Vulnerability and Adaptation of African Ecosystems to Global Climate Change CY MAR 07-15, 1995 CL HARARE, ZIMBABWE SP US Country Studies Program DE bioenergetics model; climate change; empirical models; fish yield; habitat suitability index; tropical freshwater fisheries ID FLOW INCREMENTAL METHODOLOGY; GREAT-LAKES FISH; FRESH-WATER; THERMAL HABITAT; ENVIRONMENTAL-TEMPERATURE; POTENTIAL CHANGES; AIR-TEMPERATURE; YIELDS; GROWTH; ECOSYSTEMS AB Because of the dietary and financial importance of fisheries resources in many African countries, concerns have been expressed regarding the potential for adverse impacts to fisheries resources from climate change, and a need has been identified for assessment tools that can evaluate the potential for impacts in a timely and cost-effective manner. This paper presents a framework and set of methods for assessing the potential effects of climate change on fisheries resources in Africa. The framework identifies the need to first link predicted climate changes to changes in the aquatic environment, and only then can potential impacts to aquatic resources be evaluated. The approach developed for Africa was constrained by several factors, including availability of existing data and assessment technologies, and the need for a rapid evaluation of potential climate impacts. The assessment approach employs a variety of methods including empirical models which predict changes in mortality, maximum sustainable yield, and yearly catch, a bioenergetics model, and a habitat suitability model Previously developed or newly derived site-specific empirical models can be used to compare mortality, yield, and annual catch estimates among historic, current, and predicted climate conditions. Similarly, bioenergetics modeling can be used to compare growth rates and biomass production among different climate conditions. Habitat suitability models can be developed for current climate conditions, and the effects of changes in climate-driven habitat variables such as water depth, temperature, and current velocity on habitat suitability can be evaluated for different climate conditions. Use of these approaches is recommended because they can utilize existing ecological data and do not require extensive new data collection activities, they are not technologically complex, and they can provide evaluations of potential climate change impacts in a timely and cost-effective manner. C1 US EPA,OFF POLICY PLANNING & EVALUAT,WASHINGTON,DC 20460. US EPA,ENVIRONM RES LAB,CORVALLIS,OR 97333. RP Hlohowskyj, I (reprint author), ARGONNE NATL LAB,ENVIRONM ASSESSMENT DIV,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 64 TC 3 Z9 3 U1 1 U2 12 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0936-577X J9 CLIMATE RES JI Clim. Res. PD FEB 19 PY 1996 VL 6 IS 2 BP 97 EP 106 DI 10.3354/cr006097 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA UD549 UT WOS:A1996UD54900003 ER PT J AU Baker, EN Bluntell, TL Vijayan, M Dodson, E Dodson, G Gilliland, GL Sussman, JL AF Baker, EN Bluntell, TL Vijayan, M Dodson, E Dodson, G Gilliland, GL Sussman, JL TI Publication of macromolecular crystal structures SO FEBS LETTERS LA English DT Letter C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. WEIZMANN INST SCI,DEPT BIOL STRUCT,IL-76100 REHOVOT,ISRAEL. MASSEY UNIV,DEPT CHEM & BIOCHEM,IUCR COMMISS BIOL MOLEC,PALMERSTON NORTH,NEW ZEALAND. UNIV LONDON BIRKBECK COLL,DEPT CRYSTALLOG,ICRF UNIT STRUCT MOLEC BIOL,LONDON WC1E 7HX,ENGLAND. INDIAN INST SCI,MOLEC BIOPHYS UNIT,IUCR COMMISS BIOL MOLEC,BANGALORE 560012,KARNATAKA,INDIA. UNIV YORK,DEPT CHEM,IUCR ELECTR PUBLISHING COMM,YORK YO1 5DD,N YORKSHIRE,ENGLAND. UNIV YORK,DEPT CHEM,IUCR COMM BIOL MOLEC,YORK YO1 5DD,N YORKSHIRE,ENGLAND. CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0014-5793 J9 FEBS LETT JI FEBS Lett. PD FEB 19 PY 1996 VL 380 IS 3 BP 302 EP 302 DI 10.1016/0014-5793(96)83096-1 PG 1 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA TW665 UT WOS:A1996TW66500021 ER PT J AU Chetyrkin, KG Kwiatkowski, A AF Chetyrkin, KG Kwiatkowski, A TI Second-order QCD corrections to scalar and pseudoscalar Higgs decays into massive bottom quarks SO NUCLEAR PHYSICS B LA English DT Article ID EUCLIDEAN ASYMPTOTIC EXPANSIONS; CHIRAL SYMMETRY-BREAKING; QUANTUM CHROMODYNAMICS; GREEN-FUNCTIONS; HEAVY QUARKS; BOSON DECAY; WIDTH; GAMMA-TOT(H0->HADRONS); RENORMALIZATION; PARTICLES AB Quark mass effects in O(alpha(s)(2)) QCD corrections to the decay rates of intermediate Higgs bosons are studied, The total hadronic rate and the partial decay rate into bottom quarks are analyzed for the Standard (scalar) Higgs boson as well as for pseudoscalar Higgs bosons. The calculations of three different contributions are presented. First, the flavour singlet diagrams containing two closed fermion loops are calculated for a nonvanishing bottom mass in the heavy top limit. Their leading contribution, which is of the same order as the quasi-massless nonsinglet corrections, and the subleading terms are found. Large logarithms arise due to the separation of the pure gluon final state from the bottom final states. Second, quadratic bottom mass corrections originating from nonsinglet diagrams are presented, Third, nonsinglet corrections induced by virtual heavy top quarks are calculated in leading and subleading orders. It is demonstrated that, in order a alpha(s)(2), the first contribution numerically dominates over the second and the third ones. C1 UNIV KARLSRUHE,INST THEORET TEILCHENPHYS,D-76128 KARLSRUHE,GERMANY. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. RP Chetyrkin, KG (reprint author), RUSSIAN ACAD SCI,INST NUCL RES,60TH OCTOBER ANNIVERSARY PROSPECT 7A,MOSCOW 117312,RUSSIA. NR 49 TC 54 Z9 54 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD FEB 19 PY 1996 VL 461 IS 1-2 BP 3 EP 18 DI 10.1016/0550-3213(95)00616-8 PG 16 WC Physics, Particles & Fields SC Physics GA UA315 UT WOS:A1996UA31500001 ER PT J AU Harris, BW Smith, J Vogt, R AF Harris, BW Smith, J Vogt, R TI Reanalysis of the EMC charm production data with extrinsic and intrinsic charm at NLO SO NUCLEAR PHYSICS B LA English DT Article ID PSI-PSI-PRODUCTION; LUND MONTE-CARLO; JET FRAGMENTATION; O(ALPHA-S) CORRECTIONS; E+E-PHYSICS; HEAVY; ELECTROPRODUCTION; PHOTOPRODUCTION; COLLISIONS; DISTRIBUTIONS AB A calculation of the next-to-leading order exclusive extrinsic charm quark differential distributions in deeply inelastic electroproduction has recently been completed, Using these results we compare the NLO extrinsic contributions to the charm structure function F-2(X, Q(2), m(c)(2)) with the corresponding NLO intrinsic contributions, The results of this analysis are compared with the EMC DIS charm quark data and evidence for an intrinsic charm component in the proton is found. C1 SUNY STONY BROOK, INST THEORET PHYS, STONY BROOK, NY 11794 USA. UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV NUCL SCI, BERKELEY, CA 94720 USA. UNIV CALIF DAVIS, DEPT PHYS, DAVIS, CA 95616 USA. RP FLORIDA STATE UNIV, DEPT PHYS, TALLAHASSEE, FL 32306 USA. NR 53 TC 118 Z9 118 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD FEB 19 PY 1996 VL 461 IS 1-2 BP 181 EP 196 DI 10.1016/0550-3213(95)00652-4 PG 16 WC Physics, Particles & Fields SC Physics GA UA315 UT WOS:A1996UA31500010 ER PT J AU Flynn, JM Nieves, J Bowler, KC Hazel, NM Henty, DS Hoeber, H Kenway, RD Richards, DG Gough, BJ Lellouch, LP Shanahan, HP AF Flynn, JM Nieves, J Bowler, KC Hazel, NM Henty, DS Hoeber, H Kenway, RD Richards, DG Gough, BJ Lellouch, LP Shanahan, HP TI Lattice study of the decay (B)over-bar(0)->p(+)l(-)(v)over-bar(l): Model-independent determination of vertical bar V-ub vertical bar SO NUCLEAR PHYSICS B LA English DT Article ID SEMI-LEPTONIC DECAYS; QCD SUM-RULES; SEMILEPTONIC DECAYS; FORM-FACTORS; QUARK-MODEL; B-MESONS; HEAVY; IMPROVEMENT; BBAR AB We present results of a lattice computation of the vector and axial-vector current matrix elements relevant for the semileptonic decay (B) over bar(0) --> rho(+)l(-)<(nu)over bar>(l). The computations are performed in the quenched approximation of lattice QCD on a 24(3) x 48 lattice at beta = 6.2, using an O(a) improved fermionic action. Our principal result is for the differential decay rate, d Gamma/dq(2), for the decay (B) over bar(0) --> rho(+)l(-)<(nu)over bar>(l), in a region beyond the charm endpoint, allowing a model-independent extraction of \V-ub\ from experimental measurements. Heavy quark symmetry relations between radiative and semileptonic decays of (B) over bar mesons into light vector mesons are also discussed. C1 UNIV EDINBURGH, DEPT PHYS & ASTRON, EDINBURGH EH9 3JZ, MIDLOTHIAN, SCOTLAND. FERMILAB NATL ACCELERATOR LAB, BATAVIA, IL 60510 USA. CNRS MARSEILLE LUMINY, CTR PHYS THEOR, F-13288 MARSEILLE 9, FRANCE. UNIV GLASGOW, DEPT PHYS & ASTRON, GLASGOW G12 8QQ, LANARK, SCOTLAND. RP UNIV SOUTHAMPTON, DEPT PHYS, SOUTHAMPTON SO17 1BJ, HANTS, ENGLAND. RI Nieves, Juan/K-2115-2014; OI Nieves, Juan/0000-0002-2518-4606; Flynn, Jonathan/0000-0002-6280-1677 NR 57 TC 59 Z9 59 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 EI 1873-1562 J9 NUCL PHYS B JI Nucl. Phys. B PD FEB 19 PY 1996 VL 461 IS 1-2 BP 327 EP 349 DI 10.1016/0550-3213(95)00595-1 PG 23 WC Physics, Particles & Fields SC Physics GA UA315 UT WOS:A1996UA31500016 ER PT J AU Goldin, GA Sharp, DH AF Goldin, GA Sharp, DH TI Diffeomorphism groups, anyon fields, and q commutators SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM STATISTICS; CURRENT-ALGEBRA; GENERAL-THEORY; 2 DIMENSIONS; REPRESENTATIONS; PARTICLES; SPACE AB We construct explicit anyon fields from unitary representations of the group diffeomorphisms of the plane, realizing braid group elements as paths in the plane transforming naturally under diffeomorphisms. The fields satisfy q-commutation relations, where q is the anyonic phase shift. C1 RUTGERS STATE UNIV,DEPT PHYS,NEW BRUNSWICK,NJ 08903. LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Goldin, GA (reprint author), RUTGERS STATE UNIV,DEPT MATH,NEW BRUNSWICK,NJ 08903, USA. NR 23 TC 28 Z9 30 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 19 PY 1996 VL 76 IS 8 BP 1183 EP 1187 DI 10.1103/PhysRevLett.76.1183 PG 5 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300001 ER PT J AU Kim, KJ AF Kim, KJ TI Transition undulator radiation as bright infrared source SO PHYSICAL REVIEW LETTERS LA English DT Article AB Undulator radiation contains, in addition to the usual component with narrow spectral features, a broadband component in the low frequency region emitted in the near forward direction, peaked at an angle 1/gamma, with gamma the relativistic factor. This component is caused by a sudden change in the electron's longitudinal velocity as it enters and leaves the undulator and is referred to as the transition undulator radiation, as its characteristics are very similar to the well-known transition radiation. The transition undulator radiation is potentially a bright, intense, infrared radiation source. Its radiation angular cone is much narrower than the infrared radiation from bending magnets or usual undulator harmonics. RP Kim, KJ (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 7 TC 18 Z9 18 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 FEB 19 PY 1996 VL 76 IS 8 BP 1244 EP 1247 DI 10.1103/PhysRevLett.76.1244 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300016 ER PT J AU Chiu, GS Cohen, SA AF Chiu, GS Cohen, SA TI Experimental observations of steep temperature steps in dense magnetized plasmas SO PHYSICAL REVIEW LETTERS LA English DT Article ID DOUBLE-LAYERS; EXPERIMENTAL SIMULATION; STATIONARY AB Quasi-steady-state steep temperature steps have been experimentally observed in dense (>10(19) m(-3)) linear magnetized helium plasma columns submerged in a high-density (>100 mT) neutral-gas environment. The formation of such features is found to be favored by a high neutral gas density or a positive bias (greater than or equal to V-fl) placed on the end plate. A rapid reduction in plasma density and electron temperature is observed to exist across the steps, as is a dramatic increase in neutral line radiation. Potential steps are inferred. Detailed Langmuir probe measurements have revealed three-dimensional structures. Possible mechanisms of formation an discussed. RP Chiu, GS (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 27 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 19 PY 1996 VL 76 IS 8 BP 1248 EP 1251 DI 10.1103/PhysRevLett.76.1248 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300017 ER PT J AU Hatch, DM Hu, P Saxena, A Barsch, GR AF Hatch, DM Hu, P Saxena, A Barsch, GR TI Systematic technique for the study of interphase boundaries in structural phase transitions SO PHYSICAL REVIEW LETTERS LA English DT Article AB We present a group theoretic technique based on the concepts of the direction of the order parameter (OF) and the OP isotropy group to study systematically the interphase boundaries in materials undergoing displacive transitions and construct all independent OP gradient invariants, determine primary and secondary OP profiles, domain wall energy, stability, and the phonon dispersion in the vicinity of the soft mode wave vector. We illustrate the technique for an improper ferroelastic O-h(1)-D-4h(17) transition driven by a soft M(5)(-) mode observed in alloys with CsCl structure. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. PENN STATE UNIV,MAT RES LAB,UNIVERSITY PK,PA 16802. PENN STATE UNIV,DEPT PHYS,UNIVERSITY PK,PA 16802. RP Hatch, DM (reprint author), BRIGHAM YOUNG UNIV,DEPT PHYS & ASTRON,PROVO,UT 84602, USA. NR 10 TC 12 Z9 12 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 FEB 19 PY 1996 VL 76 IS 8 BP 1288 EP 1291 DI 10.1103/PhysRevLett.76.1288 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300027 ER PT J AU Koshelev, AE AF Koshelev, AE TI Mechanism of thermally activated c-axis dissipation in layered high-T-c superconductors at high fields SO PHYSICAL REVIEW LETTERS LA English DT Article ID BI2SR2CACU2OX SINGLE-CRYSTALS; THIN-FILMS; VORTEX; STATE AB We propose a simple model which explains experimental behavior of c-axis resistivity in layered high-T-c. superconductors at high fields in a limited temperature range. It is generally accepted that the in-plane dissipation at low temperatures is caused by a small concentration of mobile pancake vortices whose diffusive motion is thermally activated. We demonstrate that in such a situation a finite conductivity appears also in the c direction due to the phase slips between the planes caused by the mobile pancakes. The model gives a universal relation between the components of conductivity which is in good agreement with experimental data. C1 RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,RUSSIA. RP Koshelev, AE (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI Koshelev, Alexei/K-3971-2013 OI Koshelev, Alexei/0000-0002-1167-5906 NR 20 TC 56 Z9 56 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 FEB 19 PY 1996 VL 76 IS 8 BP 1340 EP 1343 DI 10.1103/PhysRevLett.76.1340 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300040 ER PT J AU Hayden, SM Aeppli, G Mook, HA Perring, TG Mason, TE Cheong, SW Fisk, Z AF Hayden, SM Aeppli, G Mook, HA Perring, TG Mason, TE Cheong, SW Fisk, Z TI Comparison of the high-frequency magnetic fluctuations in insulating and superconducting La2-xSrxCuO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID 2-DIMENSIONAL HEISENBERG-ANTIFERROMAGNET; SPIN FLUCTUATIONS; ZERO TEMPERATURE; 1/S EXPANSION; LA2CUO4; DYNAMICS; STATE; CU AB Inelastic neutron scattering performed at a spallation source is used to make absolute measurements of the dynamic susceptibility of insulating La2CuO4 and superconducting La1.86Sr0.14CuO4 over the energy range 15 less than or equal to (h) over bar omega less than or equal to 350 meV. The effect of Sr doping on the magnetic excitations is to cause a large broadening in the wave vector and a substantial change in the spectrum of the local spin fluctuations. Comparison of the two compositions reveals a new energy scale (h) over bar Gamma = 22 +/- 5 meV in La1.86Sr0.14CuO4. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. RISO NATL LAB,DK-400 ROSKILDE,DENMARK. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RUTHERFORD APPLETON LAB,ISIS FACIL,DIDCOT OX11 0QX,OXON,ENGLAND. UNIV TORONTO,DEPT PHYS,TORONTO,ON M5S 1A7,CANADA. FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. RP Hayden, SM (reprint author), UNIV BRISTOL,HH WILLS PHYS LAB,TYNDALL AVE,BRISTOL BS8 1TL,AVON,ENGLAND. RI Hayden, Stephen/F-4162-2011; Mason, Thomas/M-5809-2014 OI Hayden, Stephen/0000-0002-3209-027X; Mason, Thomas/0000-0003-1880-3971 NR 33 TC 145 Z9 147 U1 1 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 19 PY 1996 VL 76 IS 8 BP 1344 EP 1347 DI 10.1103/PhysRevLett.76.1344 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300041 ER PT J AU Dabrowski, B Wang, Z Rogacki, K Jorgensen, JD Hitterman, RL Wagner, JL Hunter, BA Radaelli, PG Hinks, DG AF Dabrowski, B Wang, Z Rogacki, K Jorgensen, JD Hitterman, RL Wagner, JL Hunter, BA Radaelli, PG Hinks, DG TI Dependence of superconducting transition temperature on doping and structural distortion of the CuO2 planes in La(2-x)M(x)CuO(4) (M=Nd,Ca,Sr) SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-TC SUPERCONDUCTIVITY; COPPER OXIDES; DISAPPEARANCE; LA2-XSRXCUO4; LA2-XBAXCUO4; CUPRATE AB By comparing structural and superconducting properties of La2-x-yCaxNdyCuO4 to La2-xSrxCuO4 we have separated the effects of structure and doping on the superconducting T-c. At a fixed doping level, the highest T-c is found for flat and square CuO2 planes in the tetragonal structure. T-c is reduced by the structural distortions of the CuO2 planes in the orthorhombic structure. The local minimum of T-c vs doping observed around x similar to 0.12 indicates the presence of a weakly split singularity of the electronic density of states for the orthorhombic material. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Dabrowski, B (reprint author), NO ILLINOIS UNIV,DEPT PHYS,DE KALB,IL 60115, USA. RI Radaelli, Paolo/C-2952-2011 OI Radaelli, Paolo/0000-0002-6717-035X NR 20 TC 82 Z9 83 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 FEB 19 PY 1996 VL 76 IS 8 BP 1348 EP 1351 DI 10.1103/PhysRevLett.76.1348 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300042 ER PT J AU Roder, H Zang, J Bishop, AR AF Roder, H Zang, J Bishop, AR TI Lattice effects in the colossal-magnetoresistance manganites SO PHYSICAL REVIEW LETTERS LA English DT Article AB We study the combined influence of spin double exchange and Jahn-Teller lattice coupling to holes in the La(1-x)A(x)MnO(3) perovskites (A = Ca, Sr, Ba). Using a mean-field approximation for the double exchange and a variational Lang-Firsov approximation for the lattice degrees of freedom, we show that the lattice effects decrease the magnetic transition temperature, and also cause the maximal value of the transition temperature as a function of dopant concentration x to depend on the Jahn-Teller coupling strength. We find a continuous rapid crossover from a large polaronic state to a quasi-self-trapped small polaron state accompanying the magnetic transition. C1 LOS ALAMOS NATL LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. UNIV BAYREUTH,LEHRSTUHL THEORET PHYS 1,D-95440 BAYREUTH,GERMANY. RP Roder, H (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 16 TC 621 Z9 631 U1 11 U2 43 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 FEB 19 PY 1996 VL 76 IS 8 BP 1356 EP 1359 DI 10.1103/PhysRevLett.76.1356 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300044 ER PT J AU Ladd, AJC AF Ladd, AJC TI Hydrodynamic screening in sedimenting suspensions of non-Brownian spheres SO PHYSICAL REVIEW LETTERS LA English DT Article ID DISPERSION AB It has been suggested [D. L. Koch and E. S. G. Shaqfeh, J. Fluid Mech. 224, 275 (1991)] that the long-range hydrodynamic interactions in sedimenting suspensions of non-Brownian spheres are screened by changes in the pair correlation function. However, a large-scale numerical simulation, using more than 32000 spheres, with full many-body hydrodynamic interactions, has found no evidence of the predicted changes in suspension microstructure. The absence of hydrodynamic screening in the simulations is shown to lead to divergent velocity fluctuations, in disagreement with recent experimental results [H. Nicolai and E. Guazzelli, Phys. Fluids 7, 3 (1995)]. RP Ladd, AJC (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 12 TC 97 Z9 99 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 FEB 19 PY 1996 VL 76 IS 8 BP 1392 EP 1395 DI 10.1103/PhysRevLett.76.1392 PG 4 WC Physics, Multidisciplinary SC Physics GA TV693 UT WOS:A1996TV69300053 ER PT J AU Fantucci, P BonacicKoutecky, V Jellinek, J Wiechert, M Harrison, RJ Guest, MF AF Fantucci, P BonacicKoutecky, V Jellinek, J Wiechert, M Harrison, RJ Guest, MF TI Ab initio Hartree-Fock molecular dynamics with parallel processing: Application to small neutral and charged Li-n clusters SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ABINITIO CONFIGURATION-INTERACTION; DENSITY-FUNCTIONAL THEORY; METAL CLUSTERS; SURFACE AB An ab initio molecular dynamics scheme based on a parallelized Hartree-Fock procedure is described. Analytical gradients of the Born-Oppenheimer ground state energy are used to compute the forces acting on atoms at each nuclear configuration along trajectories generated by solving classical equations of motion. Parallel processing of the two-electron integrals and gradients and optimization of the sequential parts of the self-consistent-field procedure allow for generation of trajectories that, for small systems, are long enough to provide for a meaningful dynamical analysis. The degree of detail and completeness of this analysis approaches that previously feasible only with semiempirical potentials, This is illustrated by and Li application of the scheme to Li-6, Li-8, Li-9(+) and Li-10 clusters. C1 HUMBOLDT UNIV BERLIN,WALTHER NERNST INST PHYS & THEORET CHEM,D-10117 BERLIN,GERMANY. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. SERC,DARESBURY LAB,WARRINGTON WA4 1AD,CHESHIRE,ENGLAND. RP Fantucci, P (reprint author), UNIV MILAN,CTR CNR,DIPARTIMENTO CHIM INORGAN METALLORGAN & ANALI,VIA VENEZIAN 21,I-20133 MILAN,ITALY. NR 31 TC 36 Z9 37 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 FEB 16 PY 1996 VL 250 IS 1 BP 47 EP 58 DI 10.1016/0009-2614(95)01432-2 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TY145 UT WOS:A1996TY14500008 ER PT J AU Brandes, HK Larimer, FW Hartman, FC AF Brandes, HK Larimer, FW Hartman, FC TI The molecular pathway for the regulation of phosphoribulokinase by thioredoxin f SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID ESCHERICHIA-COLI; RIBULOSE-5-PHOSPHATE KINASE; SPINACH PHOSPHORIBULOKINASE; CYSTEINYL RESIDUE; ACTIVE-CENTER; REDUCED FORM; SITE; IDENTIFICATION; PHOTOSYNTHESIS; SULFHYDRYL AB Phosphoribulokinase (PRK) is one of several plant enzymes that is regulated by thiol-disulfide exchange as mediated by thioredoxin, which contains spatially vicinal, redox-active cysteinyl residues, In an earlier study (Brandes, H. K., Larimer, F. W., Geck, M. K., Stringer, C. D., Schurmann, P., and Hartman, F. C. (1993) J. Biol. Chem, 268, 18411-18414), our laboratory identified Cys-46 of thioredoxin f (Trx), as opposed to the other candidate Cys-49, as the primary nucleophile that attacks the disulfide of target proteins. The goal of the present study was to identify which of the two redox-active cysteinyl residues of PRK (Cys-16 or Cys-55) is paired with Cys-46 of Trx in the interprotein disulfide intermediate of the overall oxidation-reduction pathway. Incubation of a mixture of the C16S mutant of PRK and the C49S mutant of Trx with Cu2+ results in covalent complex formation as detected by SDS-polyacrylamide gel electrophoresis. Complexation is fully reversible by dithiothreitol and is retarded by ligands for PRK. Under the same conditions, Cu2+ induces very little complex formation between the following pairs of mutants: C16S PRK/C46S Trx, C55S PRK/C49S Trx, and C55S PRK/C46S Trx. When either 5-thio-2-nitrobenzoate-derivatized C16S or C55S PRK, as mimics of the oxidized (disulfide) form of the enzyme, is mixed with C49S Trx, stable covalent complex formation occurs only with the C16S PRK. Thus, two independent approaches identify Cys-55 of PRK in the intermolecular disulfide pairing with Trx. C1 OAK RIDGE NATL LAB,DIV BIOL,PROT ENGN PROGRAM,OAK RIDGE,TN 37831. UNIV TENNESSEE,GRAD SCH BIOMED SCI,OAK RIDGE,TN 37831. NR 28 TC 58 Z9 59 U1 1 U2 7 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD FEB 16 PY 1996 VL 271 IS 7 BP 3333 EP 3335 PG 3 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TV724 UT WOS:A1996TV72400001 PM 8631927 ER PT J AU Felinger, A Guiochon, G AF Felinger, A Guiochon, G TI Multicomponent interferences in overloaded gradient elution chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE overloaded gradient elution; adsorption isotherms; multicomponent interference; preparative chromatography; gradient elution; band profiles ID PREPARATIVE LIQUID-CHROMATOGRAPHY; OPTIMUM INJECTION CONDITIONS; COLUMN DESIGN PARAMETERS; OPTIMIZATION; BAND AB A theoretical study of multicomponent interferences has been performed by calculating band profiles in nonlinear overloaded gradient elution chromatography. The separation of binary and ternary mixtures has been modeled by means of a finite difference algorithm similar to the Craig mechanism, in the case when the adsorption behavior of the mixture components is accounted for by Langmuir competitive isotherms. The influence of the loading factor, the composition of the sample, and the gradient steepness have been investigated. In most cases, the profiles and the band interactions are qualitatively similar to those obtained under isocratic conditions. Although the profile fronts of the individual bands are very sharp, nearly vertical, the separation of closely eluted bands of 'parallel' or 'divergent' solutes cannot be improved significantly by gradient elution. Obviously, their retention time can be reduced considerably, which may improve the production rate although column regeneration must be carried out after each run, which increases the cycle-time. The elution profiles of impurities and trace components is usually very similar in gradient elution and in isocratic elution. This means that the recovery yield is not changed significantly, regardless of the gradient steepness. The most interesting results and the only one which is not observed under isocratic conditions, are obtained for the separation of 'convergent' solutes. In this case, the elution order of the components may change. This results in a kind of peak splitting, a fraction of the impurity eluting before the major component, the rest forming a flat profile spread dong the profile of the major component. This phenomenon can be controlled or eliminated by adjusting the loading factor of the sample and the gradient steepness. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. UNIV VESZPREM,DEPT ANALYT CHEM,H-8200 VESZPREM,HUNGARY. RI Felinger, Attila/A-1595-2008 OI Felinger, Attila/0000-0001-7130-1968 NR 18 TC 12 Z9 12 U1 1 U2 5 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 FEB 16 PY 1996 VL 724 IS 1-2 BP 27 EP 37 DI 10.1016/0021-9673(95)00912-4 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA TX704 UT WOS:A1996TX70400003 ER PT J AU Guan, H Guiochon, G AF Guan, H Guiochon, G TI Reproducibility, accuracy, and correction of isotherm data measured by chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE stationary phases, LC; isotherm data; adsorption isotherms ID PHASE LIQUID-CHROMATOGRAPHY; POLYCYCLIC AROMATIC-HYDROCARBONS; SOLID CHROMATOGRAPHY; PERFORMANCE; PACKINGS; ADSORPTION; COLUMNS; SILICA AB Using the methods of frontal analysis and elution by characteristic points, the isotherm of 3-phenyl-1-propanol was determined on four commercially available 10-mu m ODS C-18 packing materials: KROMASIL, VYDAC, YMC and ZORBAX. Each stationary phase was packed into five 10x0.46 cm I.D. columns. A methanol-water mixture (45:55, v/v) was used as the mobile phase and solvent. The column efficiencies and capacity factors were also determined for a series of compounds: m-cresol, benzyl alcohol, methyl benzoate, benzyl acetate, 2-isopropylphenol, and 2,6-dimethylphenol, all eluted under infinite dilution conditions. The average total column porosities were derived from the uracil retention volume, the internal and external porosities by reversed size-exclusion chromatography. Different columns packed with material from the same lot have significantly different thermodynamic properties. Corrections of isotherm data based on the difference between column retention factors and phase ratios do not compensate correctly for the deviations observed but corrections based on the difference of external porosities of the columns do. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. NR 30 TC 8 Z9 8 U1 0 U2 4 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 FEB 16 PY 1996 VL 724 IS 1-2 BP 39 EP 54 DI 10.1016/0021-9673(95)00888-8 PG 16 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA TX704 UT WOS:A1996TX70400004 ER PT J AU Mendelson, RA Schneider, DK Stone, DB AF Mendelson, RA Schneider, DK Stone, DB TI Conformations of myosin subfragment 1 ATPase intermediates from neutron and X-ray scattering SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE myosin subfragment 1; scattering; transition state; conformations; ATPase intermediates ID MUSCLE-CONTRACTION; ACTIN; HYDROLYSIS; COMPLEXES; VANADATE; MOTOR; HEAD AB In order to elucidate the structural changes that occur during the hydrolysis of ATP by myosin, low-angle neutron and X-ray scattering have been used to investigate the shape of the myosin head (S1) with various bound nucleotides and nucleotide analogs. It was found that the radius of gyration (R(g)) of S1 . MgADP . AlF4 and of S1 . MgADP . V-i were similar and significantly smaller (approximate to 3%) than the similar R(g) values of nucleotide-free S1, S1 . MgADP and S1 . MgADP . BeFx. In addition, S1 in the presence of MgATP, which is predominantly in the S1 . MgADP . P-i state under the experimental conditions employed, showed a change in R(g) comparable with that of S1 . MgADP . AlF4 and S1 . MgADP . V-i. The results obtained here with BeFx and AlF4 are in close harmony with crystallographic results on truncated S1 bearing M9ADP . BeFx and MgADP . AlF4. A. Fisher and co-workers have postulated that these two systems, which exhibit some structural differences, represent the pre-hydrolysis state and the transition state of ATP hydrolysis, respectively It was postulated that this structural difference might alter the orientation of the light-chain binding domain (tail) of intact S1 relative to the remainder of the molecule. Since this orientation is the major determinant of the R(g) of S1, the current data support the hypothesis that a unitary large-scale conformational cocking of S1 for subsequent force production occurs just before or during ATP hydrolysis. Modeling changes in R(g) by rigid-body rotations indicates that the longitudinal component of the force-producing throw is likely to be less than 6 nm. (C) 1996 Academic Press Limited. C1 UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. RP Mendelson, RA (reprint author), UNIV CALIF SAN FRANCISCO,CARDIOVASC RES INST,SAN FRANCISCO,CA 94143, USA. FU NCRR NIH HHS [RR-01081]; NIAMS NIH HHS [R01-AR39710, P01-AR42895] NR 31 TC 26 Z9 26 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD FEB 16 PY 1996 VL 256 IS 1 BP 1 EP 7 DI 10.1006/jmbi.1996.0063 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TU639 UT WOS:A1996TU63900001 PM 8609603 ER PT J AU Matte, A Goldie, H Sweet, RM Delbaere, LTJ AF Matte, A Goldie, H Sweet, RM Delbaere, LTJ TI Crystal structure of Escherichia coli phosphoenolpyruvate carboxykinase: A new structural family with the P-loop nucleoside triphosphate hydrolase fold SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE phosphoenolpyruvate carboxykinase; gluconeogenesis; protein crystallography ID SACCHAROMYCES-CEREVISIAE ATP; MUSCLE PYRUVATE-KINASE; RAT-LIVER GTP; ACTIVE-SITE; MACROMOLECULAR CRYSTALLOGRAPHY; STEREOCHEMICAL COURSE; REACTIVE CYSTEINE; ARGININE RESIDUES; PHASE REFINEMENT; SEQUENCE AB The crystal structure of ATP-dependent phosphoenolpyruvate carboxykinase (ATP-oxaloacetate carboxy-lyase, (transphosphorylating), E.C. 4.1.1.49; PCK) from Escherichia coli strain K12 has been determined using a combination of multiple isomorphous replacement, density modification, and partial model phase combination, and refined to a conventional X-index of 0.204 (R(free) = 0.244) at 1.9 Angstrom resolution. Each PCK molecule consists of a 275 residue N-terminal domain and 265 residue C-terminal or mononucleotide-binding domain, with the active site postulated to be within a cleft between the two domains. PCK is an open-faced, mixed alpha/beta protein, with each domain having an alpha/beta/alpha folding topology as found in several other mononucleoside-binding enzymes. The putative phosphate-binding site of ATP adopts the P-loop motif common to many ATP and GTP-binding proteins, and is similar in structure to that found within adenylate kinase. However, the beta-sheet topology within the mononucleotide-binding fold of PCK differs from all other families within the P-loop containing nucleoside triphosphate hydrolase superfamily, therefore suggesting it represents the first member in a new family of such proteins. The mononucleotide-binding domain is also different in structure compared to the classical mononucleotide-binding fold (CMBF) common to adenylate kinase, p21ras, and elongation factor-Tu. Several amino acid residues, including R65, K212, K213, H232, K254, D269, K288 and R333 appear to make up the active site of the enzyme, and are found to be absolutely conserved among known members of the ATP-dependent PCK family A cysteine residue is located near the active-site, as has been suggested for other PCKs, although in the E. coli enzyme C233 is buried and so is most likely not involved in substrate binding or catalysis. Two binding sites of the calcium-analog Tb3+ have been determined, one within the active site coordinating to the side-chain of D269, and the other within the C-terminal domain coordinating to the side-chains of E508 and E511. (C) 1996 Academic Press Limited. C1 UNIV SASKATCHEWAN,DEPT BIOCHEM,SASKATOON,SK S7N 5E5,CANADA. UNIV SASKATCHEWAN,DEPT MICROBIOL,SASKATOON,SK S7N 5E5,CANADA. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. NR 89 TC 82 Z9 83 U1 0 U2 9 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD FEB 16 PY 1996 VL 256 IS 1 BP 126 EP 143 DI 10.1006/jmbi.1996.0072 PG 18 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TU639 UT WOS:A1996TU63900010 PM 8609605 ER PT J AU Gatley, SJ Pan, DF Chen, RY Chaturvedi, G Ding, YS AF Gatley, SJ Pan, DF Chen, RY Chaturvedi, G Ding, YS TI Affinities of methylphenidate derivatives for dopamine, norepinephrine and serotonin transporters SO LIFE SCIENCES LA English DT Letter DE methylphenidate derivatives; dopamine; norepinephrine; serotonin ID POSITRON EMISSION TOMOGRAPHY; COCAINE ANTAGONISTS; I-125 RTI-55; UPTAKE SITES; BINDING; ANALOGS; INHIBITION; BRAIN; STRIATUM; RECEPTOR AB We have synthesized several derivatives of dl-threo-methylphenidate (Ritalin) bearing substituents on the phenyl ring. IC50 values for binding of these compounds to rat brain monoamine transporters were assessed using [H-3]WIN 35,428 (striatal membranes, dopamine transporters, DAT), [H-3]nisoxetine (frontal cortex membranes, norepinephrine transporters, NET) and [H-3]paroxetine (brain stem membranes, 5HT transporters, 5HTT). Affinities (1/Ki) decreased in the order: DAT > NET iodo > methoxy > hydroxy). Substitution at the meta position also increased affinity for the DAT (m-bromo > methylphenidate; m-iodo-p-hydroxy > p-hydroxy). Substitution at the ortho position with bromine considerably decreased affinity. Similar IC50 values for binding of o-bromomethylphenidate to the dopamine transporter were measured at 0, 22 and 37 degrees. N-Methylation of the piperidine ring of methylphenidate also considerably reduced affinity. The dl-erythro isomer of o-bromomethylphenidate did not bind to the DAT (IC50 > 50,000 nM). Affinities at the dopamine and norepinephrine transporters for substituted methylphenidate derivatives were well correlated (r(2) = synaptosomes corresponded well with inhibition of [H-3]WIN 35, 428 binding. None of the compounds examined exhibited significant affinity to dopamine D1 or D2 receptors (IC50 > 500 or 5,000 nM, respectively), as assessed by inhibition of binding of [H-3]SCH 23390 or [I-123]epidepride, respectively, to striatal membranes. C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP Gatley, SJ (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 40 TC 20 Z9 21 U1 3 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0024-3205 J9 LIFE SCI JI Life Sci. PD FEB 16 PY 1996 VL 58 IS 12 BP PL231 EP PL239 PG 9 WC Medicine, Research & Experimental; Pharmacology & Pharmacy SC Research & Experimental Medicine; Pharmacology & Pharmacy GA TV953 UT WOS:A1996TV95300010 ER PT J AU Mazzucato, E AF Mazzucato, E TI Fusion prospects SO SCIENCE LA English DT Letter RP Mazzucato, E (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 16 PY 1996 VL 271 IS 5251 BP 892 EP 893 DI 10.1126/science.271.5251.892 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TV704 UT WOS:A1996TV70400003 PM 17798895 ER PT J AU Alivisatos, AP AF Alivisatos, AP TI Semiconductor clusters, nanocrystals, and quantum dots SO SCIENCE LA English DT Article ID OPTICAL-PROPERTIES AB Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP Alivisatos, AP (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. RI Alivisatos , Paul /N-8863-2015 OI Alivisatos , Paul /0000-0001-6895-9048 NR 31 TC 8085 Z9 8265 U1 273 U2 2518 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 16 PY 1996 VL 271 IS 5251 BP 933 EP 937 DI 10.1126/science.271.5251.933 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TV704 UT WOS:A1996TV70400031 ER PT J AU Borgerding, AJ Wilkerson, CW AF Borgerding, AJ Wilkerson, CW TI Cryogenically cooled microloop system for sampling and injection in fast GC SO ANALYTICAL CHEMISTRY LA English DT Article ID SPEED GAS-CHROMATOGRAPHY; COLD-TRAP INLET; OPEN-TUBULAR COLUMNS; MASS-SPECTROMETRY; PRACTICAL ASPECTS; INSTRUMENTATION; STRATEGIES; PRESSURES; VAPORS AB A new inlet system for fast gas chromatography has been built in which analyte compounds in the gas phase are cryogenically trapped onto a sample loop, isolated, revaporized, and injected. Sample loops are constructed of 20 cm lengths of 50 and 100 mu m i.d. fused-silica tubing. Since the volume of these loops is small, analytes could be injected with initial bandwidths of less than 10 ms. Loops can be coated to increase the effectiveness with which compounds are trapped. Simple loops with thicker, less polar films trap hydrocarbons at relatively higher temperatures than those with more polar, thinner films. Use of 50 mu m i.d. sample loops results in narrower injection bandwidths compared to 100 Irm i.d. loops, but this does not necessarily translate into better chromatographic resolution. The wider bore tubes allow for more efficient sampling and shorter retention times for similar column head pressures. The injection system has been used to demonstrate sampling and fast GC analysis of a 10 ppbV mixture of volatile organic compounds. C1 LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,LOS ALAMOS,NM 87545. NR 28 TC 21 Z9 21 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD FEB 15 PY 1996 VL 68 IS 4 BP 701 EP 707 DI 10.1021/ac950853n PG 7 WC Chemistry, Analytical SC Chemistry GA TU971 UT WOS:A1996TU97100018 ER PT J AU Dau, H Sauer, K AF Dau, H Sauer, K TI Exciton equilibration and Photosystem II exciton dynamics - A fluorescence study on Photosystem II membrane particles of spinach SO BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS LA English DT Article DE chlorophyll; excitation energy transfer; kinetic model; photosynthesis; picosecond fluorescence; primary charge separation; thermal equilibrium ID EXCITATION-ENERGY TRANSFER; CHLOROPHYLL SPECTRAL FORMS; LIGHT-HARVESTING COMPLEX; REACTION CENTERS; PHOTOSYNTHETIC SYSTEMS; PEA-CHLOROPLASTS; C-PHYCOCYANIN; LHC-II; EMISSION; KINETICS AB The Photosystem II (PS II) exciton dynamics at room temperature was investigated by steady-state and picosecond fluorescence measurements on PS II membrane particles of spinach. In the closed as well as in the open-reaction center state, emission and excitation spectra were found to be almost independent of the excitation (lambda(ex)) and emission wavelength (lambda(em)), respectively. This holds even for anti-Stokes spectra (lambda(em) < lambda(ex)). The minor differences observed are suggestive of excitation energy transfer from short-wavelength forms of chlorophyll (Chi) to long-wavelength Chi. The relation between the emission spectrum and the excitation spectrum of the PS II antenna system is well described by the Stepanov relation (Sov. Phys. Dokl. 2 (1957) 81-84) originally derived for a single pigment in thermal equilibrium with its environment. The picosecond fluorescence decays measured at various emission wavelengths were described in terms of four exponential lifetime components with common time constants. For Chi b excitation at 645 nm, the amplitude of the fastest decay component is negative for lambda(em) > 690 nm indicating excitation energy transfer with a time constant of 15 ps. A model for the PS II exciton dynamics in the open reaction center slate is proposed which describes the fluorescence relaxation in terms of three phases: (I) ulna-fast exciton equilibration (time constants < 15 ps) within a peripheral pigment pool consisting of LHC pigments and within an inner pigment pool presumably consisting of PS II core pigments, (II) rapid exciton equilibration (time constant of 15 ps) between these two pigment pools and (III) excited state decay by primary charge separation according to the reversible radical pair model (time constants of 131 ps and 322 ps), but maintenance of the exciton equilibrium distribution, Because the equilibration time of 15 ps is fast in comparison to the mean exciton lifetime of 220 ps, the steady-state fluorescence properties are determined mainly by the thermal equilibrium distribution of excited states on the PS II chlorophylls (Chi a and Chi b). C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, STRUCT BIOL DIV, BERKELEY, CA 94720 USA. UNIV MARBURG, FB BIOL BOT, D-35032 MARBURG, GERMANY. RP Dau, H (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DEPT CHEM, BERKELEY, CA 94720 USA. NR 50 TC 63 Z9 70 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0005-2728 EI 0006-3002 J9 BBA-BIOENERGETICS JI Biochim. Biophys. Acta-Bioenerg. PD FEB 15 PY 1996 VL 1273 IS 2 BP 175 EP 190 DI 10.1016/0005-2728(95)00141-7 PG 16 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA TX212 UT WOS:A1996TX21200012 ER PT J AU Gingrich, JC Boehrer, DM Garnes, JA Johnson, W Wong, BS Bergmann, A Eveleth, GG Langlois, RG Carrano, AV AF Gingrich, JC Boehrer, DM Garnes, JA Johnson, W Wong, BS Bergmann, A Eveleth, GG Langlois, RG Carrano, AV TI Construction and characterization of human chromosome 2-specific cosmid, fosmid, and PAC clone libraries SO GENOMICS LA English DT Article ID YEAST ARTIFICIAL CHROMOSOMES; SORTED HUMAN CHROMOSOME-16; FACTOR-BASED VECTOR; FLOW-CYTOMETRY; HIGH-RESOLUTION; DNA LIBRARIES; HUMAN GENOME; GENE; HYBRIDS; CONTIG AB Three human chromosome a-specific clone libraries were constructed and characterized. Chromosome 2-specific cosmid and fosmid clone libraries were constructed using flow-sorted DNA from the monochromosomal hybrid cell line GM10826. The cosmid and fosmid libraries consist of 38,496 and 26,400 arrayed clones, respectively, with an average size of 40 kb. Colony hybridization of a representative number of clones with both human and hamster genomic DNA probes demonstrates that between 58 and 66% of the clones in the how-sorted libraries contain human inserts. Approximately 5% of the cosmid and fosmid clones are nonrecombinants. A chromosome a-specific PAC library was also produced from the hybrid cell line GM10826. DNA from the hybrid cell line was cloned, and the human chromosome a-specific clones were identified by colony hybridization. Approximately 5800 chromosome 2-specific PAC clones with an average insert size of similar to 85 kb were arrayed. Based on the size of the clones, the cosmid, fosmid, and PAC libraries are similar to 3.6x, similar to 2.5x, and similar to 1.9x, respectively, in chromosomal coverage. The chromosome 2 coverage of each of the three libraries was further determined by PCR screening clone pools with 82 chromosome 2-specific STSs. The average number of clones identified for each STS in the library indicates the cosmid, fosmid, and PAC libraries to be similar to 3.2x, similar to 2.1x, and similar to 1.5x, respectively, in chromosome coverage. All except one of the 82 STSs were represented in the portions of the libraries screened. (C) 1996 Academic Press, Inc. C1 LAWRENCE LIVERMORE NATL LAB,CTR HUMAN GENOME,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94550. NR 47 TC 28 Z9 28 U1 1 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 15 PY 1996 VL 32 IS 1 BP 65 EP 74 DI 10.1006/geno.1996.0077 PG 10 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA TW558 UT WOS:A1996TW55800008 PM 8786122 ER PT J AU Grady, DL Robinson, DL Gersh, M Nickerson, E McPherson, J Wasmuth, JJ Overhauser, J Deaven, LL Moyzis, RK AF Grady, DL Robinson, DL Gersh, M Nickerson, E McPherson, J Wasmuth, JJ Overhauser, J Deaven, LL Moyzis, RK TI The generation and regional localization of 303 new chromosome 5 sequence-tagged sites SO GENOMICS LA English DT Article ID YEAST ARTIFICIAL CHROMOSOMES; REPETITIVE DNA-SEQUENCES; HUMAN Y-CHROMOSOME; HUMAN GENOME; PHYSICAL MAP; LIBRARIES; HYBRID; MODEL; GENE AB With the ultimate goal of creating a sequence-ready physical map of all of chromosome 5, 303 new human chromosome 8-specific STS markers have been systematically generated and regionally ordered. Chromosome 5 DNA prepared from flow-sorted chromosomes was digested with restriction enzymes BamHI and HindIII and cloned in bacteriophage M13mp18. Random clones were sequenced, and appropriate PCR deoxyoligomers were synthesized. An acceptable sequence-tagged site (STS)-PCR assay yielded the appropriate size amplification product from both total human DNA and hybrid cell line DNA containing only human chromosome 5. Each STS has been regionally localized by breakpoint analysis using a set of hybrid cell panels consisting of natural deletions or translocations of human chromosome 5. This hybrid cell panel was able to localize the STSs to 1 of 51 bins on the short arm and 1 of 15 bins on the long arm. The STS markers appear to be randomly distributed along the length of this 194-Mb chromosome. The current overall density of these markers (approximately 1 STS/640 kb), combined with the numerous PCR-based physical and genetic markers generated by other groups, will provide sufficient ''nucleation points'' for YAC contig assembly and verification in any region of human chromosome 5. (C) 1996 Academic Press, Inc. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. THOMAS JEFFERSON UNIV,DEPT BIOCHEM & MOLEC BIOL,PHILADELPHIA,PA 19107. UNIV CALIF IRVINE,DEPT BIOCHEM,IRVINE,CA 92717. RP Grady, DL (reprint author), LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,MS M888,LOS ALAMOS,NM 87545, USA. NR 33 TC 11 Z9 11 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 15 PY 1996 VL 32 IS 1 BP 91 EP 96 DI 10.1006/geno.1996.0080 PG 6 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA TW558 UT WOS:A1996TW55800011 PM 8786125 ER PT J AU Birn, J Iinoya, F Brackbill, JU Hesse, M AF Birn, J Iinoya, F Brackbill, JU Hesse, M TI A comparison of MHD simulations of magnetotail dynamics SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID IN-CELL METHOD; GEOMAGNETIC TAIL; RECONNECTION; INSTABILITY; EVOLUTION; COMPUTER AB The accuracy of two resistive MHD codes based on very different methods is studied by simulating the same problem of plasmoid formation and ejection in the geomagnetic tail initiated by resistive diffusion, using identical initial and boundary conditions and a 2-D approximation. One of the codes is a modified explicit leapfrog scheme, which has been used extensively in the past for similar problems. The other scheme is an implicit particle-in-cell MHD code (FLIP-MHD). The results from both schemes agree within a few percent in all major characteristics: onset and growth rate of the instability, formation and tailward motion of a plasmoid, scale size of the perturbation and details of the mode structures. FLIP, however, predicts a slightly slower tailward motion of the plasmoid. Both simulations exhibit highly variable earthward flow from the reconnection site with similar averages and similar fluctuation levels, resembling observed bursty bulk flows. Due to differences in the phase of these fluctuations, however, the instantaneous flow may differ in the two simulations. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. NASA,GODDARD SPACE FLIGHT CTR,ELECTRODYNAM BRANCH,GREENBELT,MD 20771. RP Birn, J (reprint author), LOS ALAMOS NATL LAB,SPACE & ATMOSPHER SCI GRP,MS D466,LOS ALAMOS,NM 87545, USA. RI Hesse, Michael/D-2031-2012 NR 18 TC 20 Z9 20 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 15 PY 1996 VL 23 IS 4 BP 323 EP 326 DI 10.1029/95GL03857 PG 4 WC Geosciences, Multidisciplinary SC Geology GA TW551 UT WOS:A1996TW55100002 ER PT J AU James, CA Morris, DE Doorn, SK Arrington, CA Dunbar, KR Finnis, GM Pence, LE Woodruff, WH AF James, CA Morris, DE Doorn, SK Arrington, CA Dunbar, KR Finnis, GM Pence, LE Woodruff, WH TI Photochemistry of deca(acetonitrile) dirhodium(II) cation: Evidence for kilosecond-lived photoinduced charge separation SO INORGANICA CHIMICA ACTA LA English DT Article DE photochemistry; rhodium complexes; acetonitrile complexes; dinuclear complexes ID RHODIUM ISOCYANIDE COMPLEXES; ENERGY STORAGE REACTIONS AB Events following the photodissociation of the dinuclear rhodium(II,II) complex Rh(2)L(10) (L = CH3CN), are reported. Spectroscopic and electrochemical evidence demonstrates that this complex possesses novel reversible photochemistry with metastable photoproducts that exist for kiloseconds after photodissociation, and ultimately regenerate the original dimer. UV/Vis irradiation of acetonitrile solutions of the complex results in homolytic cleavage of the Rh-Rh bond to give a promptly formed paramagnetic transient that EPR evidence suggests to be Rh(II)L(6). This species has a half-life of ca 50 s, and initiates a reaction sequence that generates photo-disproportionated, metastable products, which are inferred to be Rh(III)L(6) and Rh-3(II,II,I)L(n) These products have half-lives in the kilosecond range. The proposed photochemical processes thus achieve photoinduced charge separation, with remarkably long lifetimes for the charge-separated species. The metastable species may be viewed as a photogenerated electron-hole pair in solution that, due to its long lifetimes, may have significant potential in converting light into usable chemical energy. C1 MICHIGAN STATE UNIV,DEPT CHEM,E LANSING,MI 48824. FURMAN UNIV,DEPT CHEM,GREENVILLE,SC 29613. RP James, CA (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,LOS ALAMOS,NM 87545, USA. RI Morris, David/A-8577-2012; Dunbar, Kim/B-6488-2015 OI Dunbar, Kim/0000-0001-5728-7805 NR 20 TC 11 Z9 11 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD FEB 15 PY 1996 VL 242 IS 1-2 BP 91 EP 96 DI 10.1016/0020-1693(96)04853-0 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA UM311 UT WOS:A1996UM31100014 ER PT J AU Lee, RT Hopkins, SR Kuo, WL Collins, C Kim, RY ODonnell, JJ AF Lee, RT Hopkins, SR Kuo, WL Collins, C Kim, RY ODonnell, JJ TI The human galactokinase 2 (GK2) gene maps to chromosome 15q21 SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,DEPT OPHTHALMOL,SAN FRANCISCO,CA 94143. LAWRENCE BERKELEY LAB,BERKELEY,CA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 4544 EP 4544 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39704537 ER PT J AU Quantock, AJ Fullwood, NJ Thonar, EJMA Waltman, SR Capel, MS Kincaid, MC Ito, M Verity, SM Schanzlin, DJ AF Quantock, AJ Fullwood, NJ Thonar, EJMA Waltman, SR Capel, MS Kincaid, MC Ito, M Verity, SM Schanzlin, DJ TI Stromal descemet's and endothelial changes in macular corneal dystrophy type II SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 ST LOUIS UNIV,SCH MED,ANHEUSER BUSCH EYE INST,ST LOUIS,MO. UNIV LANCASTER,DIV BIOL SCI,LANCASTER LA1 4YW,ENGLAND. RUSH MED COLL,CHICAGO,IL 60612. GREEN WALTMAN EYE INST,BELLEVILLE,IL. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11973. OI Fullwood, Nigel James/0000-0002-9405-8515 NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 4682 EP 4682 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39704675 ER PT J AU KwitekBlack, AE Krizman, D Carmi, R Doggett, N Stone, EM Sheffield, VC AF KwitekBlack, AE Krizman, D Carmi, R Doggett, N Stone, EM Sheffield, VC TI Fine-mapping of Bardet-Biedl syndrome focus on chromosome 16 SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 NIH,BETHESDA,MD 20892. UNIV IOWA,DEPT PEDIAT,IOWA CITY,IA 52242. UNIV IOWA,DEPT OPHTHALMOL,IOWA CITY,IA 52242. BEN GURION UNIV NEGEV,IL-84105 BEER SHEVA,ISRAEL. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 0 TC 1 Z9 1 U1 0 U2 1 PU LIPPINCOTT-RAVEN PUBL PI PHILADELPHIA PA 227 EAST WASHINGTON SQ, PHILADELPHIA, PA 19106 SN 0146-0404 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD FEB 15 PY 1996 VL 37 IS 3 BP 5160 EP 5160 PG 1 WC Ophthalmology SC Ophthalmology GA TX397 UT WOS:A1996TX39705153 ER PT J AU White, CW Budai, JD Zhu, JG Withrow, SP Zuhr, RA Hembree, DM Henderson, DO Ueda, A Tung, YS Mu, R Magruder, RH AF White, CW Budai, JD Zhu, JG Withrow, SP Zuhr, RA Hembree, DM Henderson, DO Ueda, A Tung, YS Mu, R Magruder, RH TI GaAs nanocrystals formed by sequential ion implantation SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID QUANTUM-CONFINEMENT; OPTICAL-PROPERTIES; PHOTOLUMINESCENCE; GLASS; MICROCRYSTALS; CRYSTALLITES; MATRICES AB Sequential ion implantation of As and Ga into SiO2 and alpha-Al2O3 followed by thermal annealing has been used to form zinc-blende GaAs nanocrystals in these two matrices. In SiO2, the nanocrystals are nearly spherical and randomly oriented, with diameters less than 15 nm. In Al2O3, the nanocrystals are three dimensionally aligned with respect to the crystal lattice. Infrared reflectance measurements show evidence for surface phonon modes in the GaAs nanocrystals in these matrices. (C) 1996 American Institute of Physics. C1 OAK RIDGE Y-12 PLANT,OAK RIDGE,TN 37831. FISK UNIV,NASHVILLE,TN 37208. VANDERBILT UNIV,NASHVILLE,TN 37235. RP White, CW (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. RI Budai, John/R-9276-2016 OI Budai, John/0000-0002-7444-1306 NR 28 TC 55 Z9 63 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1996 VL 79 IS 4 BP 1876 EP 1880 DI 10.1063/1.361088 PG 5 WC Physics, Applied SC Physics GA TV540 UT WOS:A1996TV54000006 ER PT J AU Howard, AJ Rye, RR Houston, JE AF Howard, AJ Rye, RR Houston, JE TI Nanomechanical basis for imaging soft materials with tapping mode atomic force microscopy SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID POLY(TETRAFLUOROETHYLENE); RADIATION; FILMS AB The surfaces of virgin and chemically etched poly(tetrafluoroethylene) (PTFE) have been studied using scanning electron microscopy (SEM), and atomic force microscopy (AFM) in both contact and tapping modes. Contact mode AFM images of this relatively soft polymeric material are dominated by tip-induced imaging artifact. When subsequent, AFM imaging was performed in tapping mode these artifacts were eliminated, and comparable tapping mode AFM and SEM images were obtained for even the highly porous, unstable surface that results from sodium naphthalenide etching. Interfacial force microscopy force versus displacement, and creep experiments were performed to determine the nanomechanical nature of virgin PTFE. These experiments show that virgin PTEE is a viscoelastic material which is capable of supporting large forces on the millisecond time scale but creeps dramatically at longer times. Clearly, with scanning probe techniques which utilize constant probe force feedback, one should expect image distortions, as we observe, with soft materials such as virgin or etched PTFE. Conversely, with tapping mode AFM, rational images require contact times (mu s) that are much shorter than creep times (ms). Thus, viscoelastic material characteristics determine the need for tapping mode AFM over contact mode AFM. By comparing tapping mode AFM images of virgin and etched PTFE surfaces, we can understand the three-dimensional character of the etched surface necessary for mechanical interlocking and resultant strong metal adhesion. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 16 TC 36 Z9 36 U1 1 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 1996 VL 79 IS 4 BP 1885 EP 1890 DI 10.1063/1.361090 PG 6 WC Physics, Applied SC Physics GA TV540 UT WOS:A1996TV54000008 ER PT J AU Alford, TL Jaquez, EJ Theodore, ND Russell, SW Diale, M Adams, D Anders, S AF Alford, TL Jaquez, EJ Theodore, ND Russell, SW Diale, M Adams, D Anders, S TI Influence of interfacial copper on the room temperature oxidation of silicon SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CU3SI AB Thick (similar to 1.3 mu m) oxide films were grown by room-temperature oxidation of silicon after low-energy copper-ion implantation, The structural properties of the silicon dioxide layer and the implanted silicon were characterized by Rutherford backscattering spectrometry and transmission-electron microscopy. During the room temperature oxidation a portion of the implanted copper resided on the surface and a portion moved with the advancing Si/SiO2 interface. This study revealed that the oxide growth rate was dependent on the amount of Cu present at the moving interface. The surface copper is essential for the dissociation of oxygen at the surface, and it is this oxygen that participates in the oxidation process. The resulting oxide formed was approximately stoichiometric silicon dioxide. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, BERKELEY, CA 94720 USA. RP ARIZONA STATE UNIV, TEMPE, AZ 85287 USA. RI Raoux, Simone/G-3920-2016 NR 18 TC 13 Z9 13 U1 0 U2 0 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 FEB 15 PY 1996 VL 79 IS 4 BP 2074 EP 2078 DI 10.1063/1.361064 PG 5 WC Physics, Applied SC Physics GA TV540 UT WOS:A1996TV54000039 ER PT J AU Xu, CS deBeer, E Neumark, DM AF Xu, CS deBeer, E Neumark, DM TI Photoelectron spectroscopy of PO2- SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPECTRUM; ABINITIO C1 LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP Xu, CS (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. RI Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 14 TC 23 Z9 25 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1996 VL 104 IS 7 BP 2749 EP 2751 DI 10.1063/1.470983 PG 3 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TU985 UT WOS:A1996TU98500032 ER PT J AU Kent, MS Smith, GS Baker, SM Nyitray, A Browning, J Moore, G Hua, DW AF Kent, MS Smith, GS Baker, SM Nyitray, A Browning, J Moore, G Hua, DW TI The effect of a silane coupling agent on water adsorption at a metal/polymer interface studied by neutron reflectivity and angle-resolved X-ray photoelectron spectroscopy SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID SURFACES; AMINOSILANE; XPS AB Neutron reflectivity and angle-resolved X-ray photoelectron spectroscopy (XPS) have been used to examine the adsorption of water to a molybdenum/polyurethane interface. The initial quasi-steady state interfacial D2O profile (obtained after similar to 1 h exposure to D2O saturated air at ambient temperature) was determined on a nanometre scale by neutron reflectivity. The profile was obtained as a function of the concentration of a silane coupling agent mixed into the bulk of the polymer. A large concentration of D2O (> 80 vol%) was observed at the interface when no silane was present. This is interpreted as a partial delamination. Roughly 2 wt% silane led to a sharp reduction in the amount of D2O at the interface. This is attributed to the silane diffusing to the interface and promoting adhesion. Samples conditioned over longer periods of time and at elevated temperature (similar to 16 h, 100% humidity at 80 degrees 0) were examined by angle-resolved XPS. For all the conditioned samples the appearance of an additional molybdenum oxidation state, and significant dissolution of the molybdenum oxide into the polymer layer were observed. These effects were readily apparent even for samples with 2 wt% silane, although the effects were slightly more pronounced with decreasing concentration of silane. Therefore, we conclude that the silane promotes adhesion of the polyurethane to the molybdenum oxide surface, but does not provide an impenetrable barrier to water or restrict its degradative effects. C1 LOS ALAMOS NATL LAB,LANSCE,LOS ALAMOS,NM 87545. MARTIN MARIETTA CORP SPECIALTY COMPONENTS INC,LARGO,FL 34649. UNIV NEW MEXICO,CTR MICROENGINEERED CERAM,ALBUQUERQUE,NM 87131. RP Kent, MS (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 14 TC 31 Z9 32 U1 1 U2 13 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD FEB 15 PY 1996 VL 31 IS 4 BP 927 EP 937 DI 10.1007/BF00352892 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA UA900 UT WOS:A1996UA90000013 ER PT J AU Hong, L Bradt, RC AF Hong, L Bradt, RC TI The effect of indentation-induced cracking on the apparent microhardness SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID ELASTIC-PLASTIC INDENTATION; SINGLE-CRYSTALS; HARDNESS; INITIATION; FRACTURE AB The phenomenon of apparent microhardness increase with increasing applied indentation test load, the reverse indentation size effect (RISE), was addressed from the viewpoint of indentation-induced cracking. The apparent microhardness when the cracking occurs was found to be related to the applied indentation test load as P-5/3. Previously published results on single crystals of silicon, GaAs, GaP and InP, which differ by a factor of four, all fall on the same line when analysed through this concept. It is concluded that the RISE is a result of the specimen cracking during the indentation. C1 UNIV ALABAMA, DEPT MET & MAT ENGN, TUSCALOOSA, AL 35487 USA. PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 20 TC 4 Z9 4 U1 0 U2 7 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD FEB 15 PY 1996 VL 31 IS 4 BP 1065 EP 1070 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA UA900 UT WOS:A1996UA90000029 ER PT J AU Zhang, J VonDreele, RB Eyring, L AF Zhang, J VonDreele, RB Eyring, L TI Structures in the oxygen-deficient fluorite-related R(n)O(2n-2) homologous series: Pr12O22 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID RESOLUTION ELECTRON-MICROSCOPY; PR24O44; OXIDES AB The crystal structure of Pr12O22 was determined utilizing Rietveld analysis of powder neutron diffraction data (P2(1)/c, a = 6.6850(2) Angstrom, b = 11.6004(4) Angstrom, c = 12.8271(4) Angstrom, beta = 99.974(1)degrees, V = 979.67(8) Angstrom(3); total variables 130, R(p) = 3.25%, wR(p) = 5.02%). This structure is different from the models previously proposed, and the basic structural element is the isolated oxygen vacancy, as observed in another more-oxidized member of the R(n)O(2n-2) series, Tb11O20. (C) 1996 Academic Press, Inc. C1 ARIZONA STATE UNIV,CTR SOLID STATE SCI,TEMPE,AZ 85287. LOS ALAMOS NATL LAB,MANUEL LUJAN JR NEUTRON SCATTERING CTR,LANSCE,LOS ALAMOS,NM 87545. RP Zhang, J (reprint author), ARIZONA STATE UNIV,DEPT CHEM & BIOCHEM,TEMPE,AZ 85287, USA. NR 22 TC 39 Z9 40 U1 0 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD FEB 15 PY 1996 VL 122 IS 1 BP 53 EP 58 DI 10.1006/jssc.1996.0081 PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA UA976 UT WOS:A1996UA97600010 ER PT J AU Brosha, EL Garzon, FH Raistrick, ID Davies, PK AF Brosha, EL Garzon, FH Raistrick, ID Davies, PK TI Low-temperature synthesis, structure, and stability of Ba2+yCu3O6 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID CU-O; NEUTRON-DIFFRACTION; X-RAY; SYSTEM; NACUO2; YBA2CU3O7-X; BACUO2+X; OXIDES; PHASE AB Single-phase powders of Ba2Cu3O6 have been prepared at 620 degrees C under 1 atm of oxygen using freeze-dried nitrate precursors. Calcinations utilizing a precursor with a 1:1 Ba:Cu stoichiometry produced a two-phase mixture of BaO2 + Ba-2 Cu3O6 and confirmed the stable, oxidized barium cuprate exists with a metal ion ratio close to 2:3. Diffraction studies suggest that Ba2Cu3O6 (Ba0.67CuO2) crystallizes in a structure closely related to the linear chain KCuO2 and NaCuO2 cuprates. It is proposed that the reduction of copper and accompanying loss of oxygen observed above 620 degrees C are accommodated by an increase in the Ba content of the structure and the formation of Ba2+yCu3O6 with 0 less than or equal to y less than or equal to 0.25. Above 710 degrees C, the high-y end member is metastable with respect to BaCuO2, although it decomposes slowly even at elevated temperatures. (C) 1996 Academic Press, Inc. C1 UNIV PENN,DEPT MAT SCI & ENGN,PHILADELPHIA,PA 19104. RP Brosha, EL (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 31 TC 8 Z9 8 U1 1 U2 4 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD FEB 15 PY 1996 VL 122 IS 1 BP 176 EP 185 DI 10.1006/jssc.1996.0099 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA UA976 UT WOS:A1996UA97600028 ER PT J AU Paranthaman, M Chakoumakos, BC AF Paranthaman, M Chakoumakos, BC TI Crystal chemistry of HgBa2Can-1CunO2n+2+delta (n=1, 2, 3, 4) superconductors SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID NEUTRON POWDER DIFFRACTION; HGBA2CUO4+DELTA; HGBA2CA2CU3O8+DELTA; HGBA2CACU2O6+DELTA; TEMPERATURE; 150-K AB Constant wavelength neutron powder diffraction data at room temperature were used to refine the crystal structures of HgBa2Can-1CunO2n+2+delta (n = 1, 2, 3, 4) superconductors, which were synthesized by solid-state reaction of the component oxides. Samples annealed both in oxygen and argon atmospheres were examined. Rietveld refinements converged to values of R(wp) 8-10% and chi(2) = 1.1-1.7 using a tetragonal cell with P4/mmm symmetry. The HgBa2CuO4+delta, HgBa2CaCu2O6+delta, and HgBa2Ca2Cu3O8+delta (n = 1, 2, and 3) samples were nearly single phase, whereas the HgBa2Ca3Cu4O10+delta (n = 4) sample was primarily a mixture of the a = 3 and 4 phases. For increasing n, the oxygen-annealed samples exhibit T-c (diamagnetic onsets) of 94, 123, 134, and 124 K, respectively, and a contraction of the CuO2 sheets (attice parameter a). The highest T-c sample, HgBa2Ca2Cu3O8+delta, has the shortest apical Cu-O bond. Consistently, the atomic displacement parameter for Hg is large. For refinements in which the Hg atomic displacement parameter is fixed at a more reasonable value, occupancies of the Hg site are significantly less than full for the n > 1 samples, suggesting that the Hg site is deficient and/or possibly occupied by atoms with smaller scattering lengths, e.g., Cu. The oxygen site within the Hg layer is partially occupied, and its occupation increases with increasing a. For the argon-annealed samples, the cell volume increases slightly due to the isotropic increase of both the cell parameters and T-c decreases. For HgBa2CaCu2O6+delta, the occupancy of the oxygen site within the Hg layer decreases upon annealing in argon, yet the T-c increased, implying that the initial carrier concentration is in the overdoped regime. (C) 1996 Academic Press, Inc. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP Paranthaman, M (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831, USA. RI Paranthaman, Mariappan/N-3866-2015; Chakoumakos, Bryan/A-5601-2016 OI Paranthaman, Mariappan/0000-0003-3009-8531; Chakoumakos, Bryan/0000-0002-7870-6543 NR 42 TC 36 Z9 36 U1 0 U2 1 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD FEB 15 PY 1996 VL 122 IS 1 BP 221 EP 230 DI 10.1006/jssc.1996.0105 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA UA976 UT WOS:A1996UA97600034 ER PT J AU Burton, HD AF Burton, HD TI Escape velocity: Cyberculture at the end of the century - Dery,M SO LIBRARY JOURNAL LA English DT Book Review RP Burton, HD (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 SN 0363-0277 J9 LIBR J JI Libr. J. PD FEB 15 PY 1996 VL 121 IS 3 BP 168 EP 168 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA TV123 UT WOS:A1996TV12300131 ER PT J AU Wang, JN Schwartz, AJ Nieh, TG Clemens, D AF Wang, JN Schwartz, AJ Nieh, TG Clemens, D TI Reduction of primary creep in TiAl alloys by prestraining SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE primary creep; TiAl alloys; microstructure ID POLYSYNTHETICALLY TWINNED CRYSTALS; DEFORMATION AB The reduction of primary creep is important for TiAl alloys. In addition to previous alloying and microstructure-controlling investigations, this study demonstrates that primary creep of TiAl alloy can also be significantly reduced by a prestraining technique. When the material was first deformed at higher stresses for a few per cent strain, it did not begin to creep at a subsequent stress lower than a critical level, even after one week under load. This behaviour is in strong contrast to that exhibited by the material without prestraining under otherwise identical conditions. The origin of this prestraining effect may stem from the observed feature that creep of TiAl alloys is recovery-controlled at low stresses. The prestraining technique may be of technological importance for prolonging the service life of a potential TiAl alloy component. C1 UNITED TECHNOL CORP,PRATT WHITNEY,JUPITER,FL 33410. RP Wang, JN (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,L-370,LIVERMORE,CA 94551, USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 23 TC 31 Z9 32 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD FEB 15 PY 1996 VL 206 IS 1 BP 63 EP 70 DI 10.1016/0921-5093(95)09993-X PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA UA457 UT WOS:A1996UA45700009 ER PT J AU Loveday, J AF Loveday, J TI The APM Bright Galaxy Catalogue SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE catalogues; galaxies, fundamental parameters; galaxies, general galaxies, photometry ID REDSHIFT SURVEY; EVOLUTION AB The APM Bright Galaxy Catalogue lists positions, magnitudes, shapes and morphological types for 14681 galaxies brighter than b(J) magnitude 16.44, over a 4180 deg(2) area of the southern sky. Galaxy and stellar images have been located from glass copy plates of the United Kingdom Schmidt Telescope (UKST) IIIaJ sky survey using the automated photographic measuring (APM) facility in Cambridge, England. The majority of stellar images are rejected by the regularity of their image surface brightness profiles. Remaining images are inspected by eye on film copies of the survey material and classed as stellar, multiple stellar, galaxy, merger or noise. Galaxies are further classified as elliptical, lenticular, spiral, irregular or uncertain. The 180 survey fields are put on to a uniform photometric system by comparing the magnitudes of galaxies in the overlap regions between neighbouring plates. The magnitude zero-point, photometric uniformity and photographic saturation are checked with CCD photometry. Finally, the completeness and reliability of the catalogue are assessed by using various internal tests and by comparison with several independently constructed galaxy catalogues. RP Loveday, J (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 30 TC 65 Z9 66 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 15 PY 1996 VL 278 IS 4 BP 1025 EP 1048 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TW478 UT WOS:A1996TW47800017 ER PT J AU Mariappan, SVS Garcia, AE Gupta, G AF Mariappan, SVS Garcia, AE Gupta, G TI Structure and dynamics of the DNA hairpins formed by tandemly repeated CTG triplets associated with myotonic dystrophy SO NUCLEIC ACIDS RESEARCH LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; 3' UNTRANSLATED REGION; MODEL-FREE APPROACH; RELAXATION; MACROMOLECULES; EXPANSION; MUTATION; ORIGIN; GENE AB Anomalous expansion of the DNA triplet (CTG)n causes myotonic dystrophy. Structural studies have been carried out on (CTG)n repeats in an attempt to better understand the molecular mechanism of repeat expansion. NMR and gel electrophoretic studies demonstrate the presence of hairpin structures for (CTG)(5) and (CTG)(6) in solution. The monomeric hairpin structure remains invariant over a wide range of salt concentrations (10-200 mM NaCl), DNA concentrations (micromolar to millimolar in DNA strand) and pH (6.0-7.5). The (CTG) hairpin contains three bases in the loop when n is odd and four bases when n is even. For both odd and even n the stacking and pairing in the stem remain the same, i.e. two hydrogen bond T . T pairs stack with the neighboring G C pairs. All the nucleotides in (CTG)5 and (CTG)(6) adopt C2'-endo, anti conformations. Full-relaxation matrix analysis has been performed to derive the NOE distance constraints from NOESY experiments at seven different mixing times (25, 50, 75, 100, 125, 200 and 500 ms). NOESY-derived distance constraints were subsequently used in restrained molecular dynamics simulations to obtain a family of structures consistent with the NMR data. The theoretical order parameters are computed for H5-H6 (cytosines) and H2'-H2'' dipolar correlations for both (CTG)5 and (CTG)(6) by employing the Lipari-Szabo formalism. Experimental data show that the cytosine in the loop of the (CTG)(5) hairpin is slightly more flexible than those in the stem. The cytosine in the loop of the (CTG)(6) hairpin is extremely flexible, implying that the dynamics of the four base loop is intrinsically different from that of the three base loop. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 36 TC 51 Z9 51 U1 0 U2 2 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD FEB 15 PY 1996 VL 24 IS 4 BP 775 EP 783 DI 10.1093/nar/24.4.775 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TX135 UT WOS:A1996TX13500032 PM 8604323 ER PT J AU Mariappan, SVS Catasti, P Chen, X Ratliff, R Moyzis, RK Bradbury, EM Gupta, G AF Mariappan, SVS Catasti, P Chen, X Ratliff, R Moyzis, RK Bradbury, EM Gupta, G TI Solution structures of the individual single strands of the fragile X DNA triplets (GCC)(n)center dot(GGC)(n) SO NUCLEIC ACIDS RESEARCH LA English DT Article ID REPEAT; GENE; MUTATIONS; HAIRPIN; DISEASE; REGION; FMR-1; NMR AB Three-dimensional structures of the fragile X triplet repeats (GCC)(n) and (GGC)(n) are derived by using one-dimensional/two-dimensional NMR. Under a wide range of solution conditions (10-150 mM NaCl, pH 6-7) (GCC)(5-7) strands form exclusively slipped hairpins with a 3' overhanging C. The slipped hairpins of (GCC)(n) strands show the following structural characteristics: (i) maximization of Watson-Crick G . C pairs; (ii) formation of C . C mispairs at the CpG steps in the stem; (iii) C2'-endo, anti conformations for all the nucleotides. The ability of (GCC)(n) strands to form hairpin structures more readily than complementary (GGC)(n) strands suggests preferential slippage during replication and subsequent expansion of the (GCC)(n) strands. In addition, the C . C mispairs at the CpG site of (GCC)(n) hairpins account for their exceptional substrate efficiencies for human methyltransferase. Gel electrophoresis data show that (GGC)(n) strands form both hairpin and mismatched duplex structures in 10-150 mM NaCl (pH 6-7) for n < 10, but for n greater than or equal to 11 hairpin structures are exclusively present. However, (GGC)(n) strands remain predominantly in the duplex state for n = 4-11 under NMR solution conditions, which require DNA concentrations 100- to 1000-fold higher than in gel electrophoresis. NMR analyses of [(GGC)(n)](2) duplexes for n = 4-6 show the presence of Watson-Crick G . C and mismatched G(anti). G(syn) pairs. The mismatches adjacent to the CpG step introduce local structural flexibility in these duplexes, Similar structural properties are also expected in the stem of the hairpins formed by (GGC)(n) strands. C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95616. LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. NR 27 TC 64 Z9 64 U1 0 U2 5 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD FEB 15 PY 1996 VL 24 IS 4 BP 784 EP 792 DI 10.1093/nar/24.4.784 PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TX135 UT WOS:A1996TX13500033 PM 8604324 ER PT J AU Haaland, CM AF Haaland, CM TI Laser electron acceleration in vacuum - Response SO OPTICS COMMUNICATIONS LA English DT Article AB Response is made to criticisms on Haaland's paper on acceleration of electrons by laser beams in vacuum. All claims by critics are refuted. RP Haaland, CM (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD FEB 15 PY 1996 VL 124 IS 1-2 BP 74 EP 78 DI 10.1016/0030-4018(95)00619-2 PG 5 WC Optics SC Optics GA UE307 UT WOS:A1996UE30700013 ER PT J AU Tsang, TYF AF Tsang, TYF TI Surface-plasmon-enhanced third-harmonic generation in thin silver films SO OPTICS LETTERS LA English DT Article ID 2ND-HARMONIC GENERATION; EXCITATION; REFLECTION; METALS AB Optical third-harmonic generation (THG) is dipole allowed. I report a 10(3) signal enhancement of THG that is due to the excitation of a surface plasmon in thin silver films by an attenuated-total-internal-reflection geometry. Because the THG signal depends on the cube of the incident intensity and the second-harmonic generation depends on the square of the intensity, the THG overtakes the second-harmonic generation at laser intensities beyond 6 x 10(11) W/cm(2). (C) 1996 Optical Society of America RP Tsang, TYF (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 15 TC 38 Z9 39 U1 1 U2 10 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD FEB 15 PY 1996 VL 21 IS 4 BP 245 EP 247 DI 10.1364/OL.21.000245 PG 3 WC Optics SC Optics GA TV855 UT WOS:A1996TV85500005 PM 19865367 ER PT J AU Swenson, CA AF Swenson, CA TI Expansivity and heat capacity data for Lu and Sc crystals from 1 to 300 K: Spin-fluctuation and electron-phonon effects SO PHYSICAL REVIEW B LA English DT Article ID ELECTROTRANSPORT-PURIFIED SCANDIUM; SINGLE-CRYSTALS; TEMPERATURE; LUTETIUM; GADOLINIUM; HYDROGEN; ALLOYS AB Linear thermal expansivity (alpha) measurements from 1 to 300 K and heat capacity (C-p) measurements from 1 to 110 K are reported for single crystals of the hexagonal scandium and lutetium metals; the C, data were combined with previous data to obtain smooth representations to 305 K for Lu and 350 K for Sc. The Theta(0)'s (352 and 190 K, respectively, for Sc and Lu) and gamma's (10.38 and 8.30 mJ/mol K-2, respectively for Sc and Lu) are in reasonable agreement with previous data of various kinds. Electronic contributions are much larger for the alpha's than for the C-p's, with the large anisotropies of the alpha's primarily electronic in origin. The equivalent Debye Theta's for the lattice C-p's and the Gruneisen parameters Gamma for the lattice alpha's both show an unexpected T dependence at ''high'' T (T greater than or similar to Theta(0)/2), which can be associated with the disappearance of spin-fluctuation and electron-phonon enhancements to the electronic properties; this effect has been reported previously for Sc C-p's by Pleschiutschnig et al. [Phys. Rev. B 44, 6794 (1991)]. While the resulting high-temperature ''bare'' or ''density of states'' gamma for Sc, gamma(b)=5.75(25) mJ/mol K-2, is slightly larger than that calculated recently by Gotz and Winter [J, Phys. Condens. Matter 5, 1721 (1993)], the magnitude of the sum (gamma(spin)+gamma(ep)) agrees well. For Lu, for which no recent calculations exist, gamma(b)=5.50(25) mJ/mol K-2. The various Gamma's (a and c axis, lattice, and electronic) generally are quite anisotropic, with no obvious correlation between high- and low-T behavior. The anisotropy in Gamma which is associated with the enhancement (spin plus e-p) contribution is very large, with similar magnitudes for the c-axis values (similar to 17), but + for Lu and - for Sc. A 186-at. ppm Fe impurity in the scandium crystals makes a significant contribution to all of the data below 3.5 K. The resulting impurity Gamma's are very large and very anisotropic (Gamma(a)(Fe)=-40, Gamma(c)(Fe)=30). C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Swenson, CA (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 35 TC 8 Z9 8 U1 2 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 7 BP 3669 EP 3679 DI 10.1103/PhysRevB.53.3669 PG 11 WC Physics, Condensed Matter SC Physics GA TW981 UT WOS:A1996TW98100011 ER PT J AU Swenson, CA AF Swenson, CA TI Linear thermal expansivity and C-p measurements for LuHx and LuDx (x=0.005 and 0.053) single crystals SO PHYSICAL REVIEW B LA English DT Article ID TEMPERATURE HEAT-CAPACITY; TOTAL-ENERGY CALCULATIONS; LUTETIUM-HYDROGEN; YTTRIUM; METALS; RESISTIVITY; DEUTERIUM; SCANDIUM; BEHAVIOR; DYNAMICS AB Linear thermal expansivity (alpha) measurements from 1 to 300 K and heat capacity (C-p) measurements from 1 to 110 K are reported for single crystals of the alpha-Lu hexagonal alloys LuHx and LuDx (x=0.005 and 0.053). The C-p data confirm and extend to 110 K earlier 1 to 20 K measurements on LuHx alloys, and, in addition, show that isotope effects, if any, are small. The small x dependences of the C(p)s above 8 K can be associated with small increases in the Debye temperature Theta(0). This latter interpretation, which is consistent with ultrasonic and other results for these alloys, is valid only if C, is expressed as mJ/g mol K (essentially, per mole of Lu ions). The present results are in agreement with the previous conclusion from more extensive polycrystalline LuHx data that the shape of the low-temperature C-p vs T relation for x less than or equal to 0.015 is qualitatively different from that for x greater than or equal to 0.032. The linear thermal expansivities of the c-axis alloys, even for x=0.005, are significantly smaller (by from 3% to 20%) than those for the pure crystals, with large isotope effects and a large, nonlinear x dependence for the low-temperature expansivity data. Other types of data have shown a feature near 170 K which is associated with the completion of pairing of the hydrogens along the c axis in next-nearest-neighbor tetrahedral sites. A distinct (approximately 15 K wide) change in cu which is observed near this temperature for each alloy, except for a-axis LuD0.005, provides the most direct evidence of such a transition. The temperature of the c-axis discontinuity is slightly isotope and x dependent, and scales approximately with x [+24% on warming for LuH(or D)(0.053)]. The LuH0.053 a-axis alpha's show a transition at the same temperature but of opposite sign (-15% on warming). A large relative decrease in the expansivities of each of the alloys between T=0 and the transition can be ascribed to a more rapid disappearance of the spin-fluctuation and electron-phonon enhancement terms for the alloys than for the pure metal. The large differences in the isotope and x dependences of the alpha vs T relations support the postulate that the state of these alloys is quite different for x less than or equal to 0.015 and x greater than or equal to 0.032. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & ASTRON,AMES,IA 50011. RP Swenson, CA (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. NR 46 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 7 BP 3680 EP 3691 DI 10.1103/PhysRevB.53.3680 PG 12 WC Physics, Condensed Matter SC Physics GA TW981 UT WOS:A1996TW98100012 ER PT J AU Zhang, LZ AF Zhang, LZ TI Chern-Simons field theory of two-dimensional electrons in the lowest Landau level SO PHYSICAL REVIEW B LA English DT Article ID COLLECTIVE EXCITATIONS; QUANTUM; SYSTEMS; CONSTRAINT; MODEL AB We propose a fermion Chem-Simons field theory describing two-dimensional electrons in the lowest Landau level. This theory is constructed with a complete set of states, and the lowest-landau-level constraint is enforced through a delta functional described by an auxiliary field lambda. Unlike the field theory constructed directly with the states in the lowest Landau level, this theory allows one, utilizing the physical picture of ''composite fermion,'' to study the fractional quantum Hall states by mapping them onto certain integer quantum Hall states; but, unlike its application in the unconstrained theory, such a mapping is sensible only when interactions between electrons are present. An ''effective mass,'' which characterizes the scale of low energy excitations in the fractional quantum Hall systems, emerges naturally from our theory. We study a Gaussian effective theory and interpret physically the dressed stationary point equation for lambda as an equation for the ''mass renormalization'' of composite fermions. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP Zhang, LZ (reprint author), UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996, USA. NR 48 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 7 BP 3937 EP 3951 DI 10.1103/PhysRevB.53.3937 PG 15 WC Physics, Condensed Matter SC Physics GA TW981 UT WOS:A1996TW98100040 ER PT J AU Lee, H Klein, MV Olson, JM Hsieh, KC AF Lee, H Klein, MV Olson, JM Hsieh, KC TI CuPt-type ordering and dopant effect of In0.5Ga0.5-P/GaAs using spectroscopic ellipsometry SO PHYSICAL REVIEW B LA English DT Article ID VAPOR-PHASE EPITAXY; BAND-GAP ENERGY; OPTICAL-PROPERTIES; SEMICONDUCTOR ALLOYS; TEMPERATURE-DEPENDENCE; ELECTRONIC-STRUCTURE; GA0.5IN0.5P; GAINP; GAAS; ELECTROREFLECTANCE AB The CuPt-type ordering and dopant effects of In0.5Ga0.5P/GaAs epitaxial layers have been studied using spectroscopic ellipsometry and transmission electron microscopy. The degree of ordering was estimated by both transmission electron diffraction and the position of the direct band edge E(0). Conventional line-shape fitting of E(1), E(1) + Delta(1), and E(0) gaps using the second derivative of pseudodielectric functions shows that the peak position of the El gap is a function of CuPt-type ordering and carrier concentration whereas the linewidth and phase depend mainly on carrier concentration. The decrease of the El gap is explained in terms of CuPt-type ordering and doping related band-gap renormalization. In contrast to the E, gap, all these line-shape parameters of the E'(0) gap depend mainly on CuPt-type ordering. Finally, we compare our data with a recent band-structure calculation. C1 UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61801. SANDIA NATL LABS,DEPT 1113,ALBUQUERQUE,NM 87185. NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. UNIV ILLINOIS,DEPT ELECT & COMP ENGN,URBANA,IL 61801. NR 47 TC 12 Z9 12 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 7 BP 4015 EP 4022 DI 10.1103/PhysRevB.53.4015 PG 8 WC Physics, Condensed Matter SC Physics GA TW981 UT WOS:A1996TW98100050 ER PT J AU Rubio, A Miyamoto, Y Blase, X Cohen, ML Louie, SG AF Rubio, A Miyamoto, Y Blase, X Cohen, ML Louie, SG TI Theoretical study of one-dimensional chains of metal atoms in nanotubes SO PHYSICAL REVIEW B LA English DT Article ID CARBON NANOTUBES; PSEUDOPOTENTIALS; INTERCALATION; POTASSIUM; GRAPHITE AB Using first-principles total-energy pseudopotential calculations, we have studied the properties of chains of potassium and aluminum in nanotubes. For BN tubes, there is little interaction between the metal chains and the tubes, and the conductivity of these tubes is through carriers located at the inner part of the tube. In contrast, for small radius carbon nanotubes, there are two types of interactions: charge-transfer (dominant for alkali atoms) leading to strong ionic cohesion, and hybridization (for multivalent metal atoms) resulting in a smaller cohesion. For Al-atomic chains in carbon tubes, we show that both effects contribute. Electronic properties related to these confined atomic chains of metal are analyzed. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV VALLADOLID,DEPT FIS TEOR,E-47011 VALLADOLID,SPAIN. NEC CORP LTD,FUNDAMENTAL RES LABS,TSUKUBA,IBARAKI 305,JAPAN. RP Rubio, A (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Rubio, Angel/A-5507-2008; OI Rubio, Angel/0000-0003-2060-3151; Miyamoto, Yoshiyuki/0000-0001-6834-0499 NR 32 TC 90 Z9 90 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 7 BP 4023 EP 4026 DI 10.1103/PhysRevB.53.4023 PG 4 WC Physics, Condensed Matter SC Physics GA TW981 UT WOS:A1996TW98100051 ER PT J AU Bartelt, MC Gunther, S Kopatzki, E Behm, RJ Evans, JW AF Bartelt, MC Gunther, S Kopatzki, E Behm, RJ Evans, JW TI Island-size distributions in submonolayer epitaxial growth: Influence of the mobility of small clusters SO PHYSICAL REVIEW B LA English DT Article ID DIFFUSION AB We examine the influence of dimer mobility on the size distribution of two-dimensional islands formed by irreversible nucleation and growth during deposition. We first characterize the transition in scaling of the mean island density with increasing dimer mobility, from the classic form described by Venables [Philos. Mag. 27, 697 (1973)] to the modified form for ''rapid'' mobility described by Villain et al. [J. Phys. (France) I 2, 2107 (1992)]. The corresponding transition in the asymptotic scaling function describing the shape of the island-size distribution is then also characterized. In addition, we contrast the mean-field form of the scaling function for rapid dimer mobility with that for zero mobility. Analysis of experimental data for Au/Au(100), Fe/Fe(100), Cu/Cu(100), and Pt/Pt(111) homoepitaxy reveals no clear evidence for a regime of modified island density scaling due to rapid dimer mobility. However, for Fe/Fe(100) below 400 K, we argue that mobility of small clusters significantly influences the shape of the island-size distribution, even before it affects the mean island density. C1 UNIV ULM, ABT OBERFLACHENCHEM & KATALYSE, D-89069 ULM, GERMANY. IOWA STATE UNIV SCI & TECHNOL, DEPT MATH, AMES, IA 50011 USA. IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. RP IOWA STATE UNIV SCI & TECHNOL, INST PHYS RES & TECHNOL, AMES, IA 50011 USA. NR 31 TC 58 Z9 59 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 7 BP 4099 EP 4104 DI 10.1103/PhysRevB.53.4099 PG 6 WC Physics, Condensed Matter SC Physics GA TW981 UT WOS:A1996TW98100060 ER PT J AU Pietrass, T Bifone, A Room, T Hahn, EL AF Pietrass, T Bifone, A Room, T Hahn, EL TI Optically enhanced high-field NMR of GaAs SO PHYSICAL REVIEW B LA English DT Article ID HIGH-PURITY GAAS AB The Ga-69 NMR signals of differently doped GaAs samples were directly observed under optical pumping conditions in high magnetic field (4.2 T). This technique greatly enhances the sensitivity of the NMR signals and allowed us to study the effect of optical pumping on the nuclear polarization under conditions very different from optically detected NMR. The strongest NMR signals were observed when pumping with a light energy below the band gap, suggesting the involvement of impurities and defects for the most efficient polarization transfer. Inversion of the helicity of the pumping light at the lowest temperatures results in a phase inversion of the NMR signal of a bulk-GaAs and a Si-doped sample, but no phase inversion was observed for a Be-doped sample. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RI Room, Toomas/A-6412-2008 OI Room, Toomas/0000-0002-6165-8290 NR 17 TC 25 Z9 25 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP 4428 EP 4433 DI 10.1103/PhysRevB.53.4428 PG 6 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700035 ER PT J AU Froyen, S Zunger, A AF Froyen, S Zunger, A TI Surface segregation and ordering in III-V semiconductor alloys SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-BEAM EPITAXY; PHASE-DIAGRAMS; THERMODYNAMIC PROPERTIES; QUANTUM-WELLS; HETEROSTRUCTURES; OPTIMIZATION AB Using the first-principles total-energy pseudopotential method, we have studied the formation energy of the (001) Ga1-xInxP alloy surface as a function of composition and reconstruction. The results are presented as T=0 surface stability diagrams that show the lowest energy reconstruction and cation occupation pattern as functions of the chemical potentials. Slightly different stability diagrams emanate depending on whether or not there is equilibrium between the surface and the bulk. The stability diagrams show a pronounced asymmetry between the Ga- and In-rich regions. The asymmetry is interpreted in terms of the size difference between In and Ga and the effect of this size difference on the bonding geometry. For surfaces in equilibrium with the bulk, we find a strong dependence of surface segregation on the surface reconstruction, and we predict a Ga enrichment of the surface in the moderate cation-rich limit and In enrichment in the anion-rich region. This result suggests a way to achieve abrupt interfaces in semiconductor heterostructures. For surfaces not in equilibrium with the bulk, we identify regions in the stability diagram where surface-induced CuPt ordering (both type A and type B) occurs. RP Froyen, S (reprint author), NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013 NR 24 TC 57 Z9 59 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP 4570 EP 4579 DI 10.1103/PhysRevB.53.4570 PG 10 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700054 ER PT J AU Davids, PS Saxena, A Smith, DL AF Davids, PS Saxena, A Smith, DL TI Bipolaron lattice formation at metal-polymer interfaces SO PHYSICAL REVIEW B LA English DT Article ID LIGHT-EMITTING-DIODES; CONDUCTING POLYMERS; POLYACETYLENE; EFFICIENCY; POLARONS; EMISSION AB We describe a model for metal-polymer interfaces based on the nondegenerate continuum model of Bra zovskii and Kirova for the electronic properties of polymers. The correct analytic equations for a bipolaron lattice in this model are stated and the electronic properties of the bulk polymer, i.e., the energy-level structure, the energy density, and the chemical potential asa function of electron density are obtained numerically. We find that the bipolaron lattice is unstable at high densities when the intrinsic gap parameter exceeds a critical fraction of the total energy gap. The electronic properties of the bulk polymer are used for modeling the metal-polymer interface. The charge density near a metal-polymer interface is found from the electrostatic potential and an analytic expression for the bipolaron chemical potential assuming:that the contact is in equilibrium with the polymer layer. Poisson's equation is integrated to determine the electrostatic potential. We find that a large charge density is transferred into the polymer layer if the Fermi level of the metal contact is higher than the negative bipolaron formation energy per particle or lower than the positive bipolaron formation energy per particle. The transferred charge lies very close to the metal-polymer interface as a bipolaron lattice with charge density progressively decreasing away from the interface. The transferred charge gives rise to a region of rapid ''band bending,'' pins the Fermi level, and establishes the effective Schottky energy barrier. Upon increasing the metal Fermi level above the bipolaron formation energy per particle, the effective Schottky barrier saturates at the energy difference between the polaron formation energy and the bipolaron formation energy per particle. The model results are useful in interpreting recent measurements of internal photoemission, device electroabsorption,and capacitance-voltage characteristics in polymer light-emitting diodes. C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP Davids, PS (reprint author), LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. RI Davids, Paul/D-1550-2010 NR 27 TC 44 Z9 44 U1 0 U2 14 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP 4823 EP 4833 DI 10.1103/PhysRevB.53.4823 PG 11 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700083 ER PT J AU Reisfeld, G Jisrawi, NM Ruckman, MW Strongin, M AF Reisfeld, G Jisrawi, NM Ruckman, MW Strongin, M TI Hydrogen absorption by thin Pd/Nb films deposited on glass SO PHYSICAL REVIEW B LA English DT Article ID ELASTIC INTERACTION; NIOBIUM; METALS; NB; TA AB Hydrogen absorption by 200-2000-Angstrom-thick Pd-capped Nb films, between 5 and 110 degrees C, was studied by simultaneous four-probe resistivity and volumetric measurements. The resistivity as a function of hydrogen concentration was measured while charging the films with hydrogen, and was used to compute the change in hydrogen concentration in the film, during the reaction with oxygen. For the thinnest films (200 Angstrom thick), the hydrogen charging and discharging curves indicate that a first-order gas-liquid-like phase transition with a T-c of 70-75 degrees C takes place. The H-Nb phase diagram for the 200-Angstrom film looks like the W/bulk Nb alpha,alpha' phase diagram which has a higher T-c (173 degrees C). We attribute the substantial modifications of the film's phase diagram to the clamping of the Nb film at its interfaces with glass and Pd and to the nanostructure of the films. RP Reisfeld, G (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP 4974 EP 4979 DI 10.1103/PhysRevB.53.4974 PG 6 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700099 ER PT J AU Jaffe, JE Pandey, R Zapol, P AF Jaffe, JE Pandey, R Zapol, P TI Ab initio prediction of GaN (10(1)over-bar0) and (110) anomalous surface relaxation SO PHYSICAL REVIEW B LA English DT Article ID COMPOUND SEMICONDUCTORS; ATOMIC GEOMETRIES; TOTAL-ENERGY; III-V; GAAS(110); ZNS; RECONSTRUCTIONS; DEPENDENCE; IONICITY; CUCL AB The results of a study of the surface relaxation of GaN in the framework of the ab initio (all-electron) Hartree-Fock method are presented. We perform total-energy calculations using a two-dimensionally periodic slab model for the most stable nonpolar cleavage faces, namely, the (<10(1)over bar 0>) and (110) surfaces of the wurtzite and zinc-blende phases, respectively. For both surfaces, when the energy is minimized the Ga-N surface bonds show a very small rotation angle of about 6 degrees accompanied by a reduction in surface bond length of about 7%. This result differs from the well-accepted model of the GaP (110) and GaAs (110) surfaces, where there is a large rotational angle in the range of 27 degrees-31 degrees and little change in surface bond length. The structure dependence of the calculated density of states suggests that this difference is at least partly due to interaction of the Ga 3d states with N 2s-derived states in GaN. Partial double-bond character in the surface bond may also be important. C1 MICHIGAN TECHNOL UNIV, DEPT PHYS, HOUGHTON, MI 49931 USA. RP Jaffe, JE (reprint author), PACIFIC NW LAB, ENVIRONM MOL SCI LAB, RICHLAND, WA 99352 USA. RI Zapol, Peter/G-1810-2012 OI Zapol, Peter/0000-0003-0570-9169 NR 34 TC 43 Z9 43 U1 1 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP R4209 EP R4212 PG 4 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700005 ER PT J AU Rittner, JD Seidman, DN Merkle, KL AF Rittner, JD Seidman, DN Merkle, KL TI Grain-boundary dissociation by the emission of stacking faults SO PHYSICAL REVIEW B LA English DT Article ID RESOLUTION ELECTRON-MICROSCOPY; EMBEDDED-ATOM-METHOD; FCC METALS; ENERGY; AG AB A range of [110] symmetric tilt grain boundaries (GB's) are investigated in several fee metals with simulations and high-resolution electron microscopy. Boundaries with tilt angles between 50.5 degrees and 109.5 degrees dissociate into two boundaries 0.6 to 1.1 nm apart. The dissociation takes place by the emission of sticking faults from one boundary that are terminated by Shockley partials at a second boundary. This is a general mode of GB relaxation for low stacking fault energy metals. The reasons for the occurrence of this relaxation mode are discussed using the theory of GB dislocations. C1 NORTHWESTERN UNIV,ROBERT R MCCORMICK SCH ENGN & APPL SCI,MAT RES CTR,EVANSTON,IL 60208. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP Rittner, JD (reprint author), NORTHWESTERN UNIV,ROBERT R MCCORMICK SCH ENGN & APPL SCI,DEPT MAT SCI & ENGN,EVANSTON,IL 60208, USA. RI Seidman, David/B-6697-2009 NR 22 TC 57 Z9 57 U1 1 U2 17 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP R4241 EP R4244 PG 4 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700013 ER PT J AU Stumpf, R AF Stumpf, R TI H-enhanced mobility and defect formation at surfaces: H on Be(0001) SO PHYSICAL REVIEW B LA English DT Article ID HYDROGEN ADSORPTION; DIFFUSION; PT(111) AB First-principles calculations of the interaction of H with the close-packed Be(0001) surface reveal that adsorbed H reduces barriers and formation energies for Be surface defects. A H atom adsorbed on top of a Be adatom reduces the Be atom's surface-diffusion barrier by a factor of 3. Preferential binding of H to surface defects reduces the formation energy df steps, adatoms, and vacancies on Be(0001). Because H adatoms repel each other on the flat surface, but not if adsorbed at the defects studied here, the formation of these defects is especially facile at high H coverage. These results explain the experimental findings that the H-induced vacancy reconstructions, which dominate the high H coverage regime, form at as low as 100 K. RP Stumpf, R (reprint author), SANDIA NATL LABS,POB 5800,MS-1413,ALBUQUERQUE,NM 87185, USA. NR 21 TC 26 Z9 26 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP R4253 EP R4256 PG 4 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700016 ER PT J AU Xu, J Overbury, SH Wendelken, JF AF Xu, J Overbury, SH Wendelken, JF TI Selective laser removal of the dimer layer from Si(100) surfaces revealed by scanning tunneling microscopy SO PHYSICAL REVIEW B LA English DT Article ID GAP 110 SURFACES; DEFECTS; RECONSTRUCTION AB Scanning tunneling microscopy (STM) of laser-irradiated Si(100) surfaces shows that the dimerized outermost layer can be selectively removed by a pulsed Nd:YAG laser with a fluence below the melt threshold. The atoms in the laser-uncovered second layer are close to positions of a bulk terminated (1 x 1) structure, but with a slight pairing, while dimers retain a (2 x 1) configuration in the first layer. The pairing distance and fraction of the remaining dimers decrease with increasing laser exposures. The laser-uncovered layer also remains free of vacancies. RP Xu, J (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 17 TC 28 Z9 28 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1996 VL 53 IS 8 BP R4245 EP R4248 PG 4 WC Physics, Condensed Matter SC Physics GA TZ177 UT WOS:A1996TZ17700014 ER PT J AU Derrick, M Krakauer, D Magill, S Mikunas, D Musgrave, B Repond, J Stanek, R Talaga, RL Zhang, H Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Bruni, P Romeo, GC Castellini, G Chiarini, M Cifarelli, L Cindolo, F Contin, A Corradi, M Gialas, I Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Nemoz, C Palmonari, F Polini, A Sartorelli, G Timellini, R Garcia, YZ Zichichi, A Bornheim, A Crittenden, J Desch, K Diekmann, B Doeker, T Eckert, M Feld, L Frey, A Geerts, M Grothe, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Katz, UF Mengel, S Mollen, J Paul, E Pfeiffer, M Rembser, C Schramm, D Stamm, J Wedemeyer, R CampbellRobson, S Cassidy, A Cottingham, WN Dyce, N Foster, B George, S Hayes, ME Heath, GP Heath, HF Morgado, CJS OMara, JA Piccioni, D Roff, DG Tapper, RJ Yoshida, R Rau, RR Arneodo, M Ayad, R Capua, M Garfagnini, A Iannotti, L Schioppa, M Susinno, G Bernstein, A Caldwell, A Cartiglia, N Parsons, JA Ritz, S Sciulli, F Straub, PB Wai, L Yang, S Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Piotrzkowski, K Zachara, M Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowalski, T Przybycien, M RulikowskaZarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Beier, H Bienlein, JK Coldewey, C Deppe, O Desler, K Drews, G Flasinski, M Gilkinson, DJ Glasman, C Gottlicher, P GrosseKnetter, J Gutjahr, B Haas, T Hain, W Hasell, D Hessling, H Iga, Y Johnson, KF Joos, P Kasemann, M Klanner, R Koch, W Kopke, L Kotz, U Kowalski, H Labs, J Ladage, A Lohr, B Lowe, M Luke, D Mainusch, J Manczak, O Monteiro, T Ng, JST Nickel, S Notz, D Ohrenberg, K Roco, M Rohde, M Roldan, J Schneekloth, U Schulz, W Selonke, F Stiliaris, E Surrow, B Voss, T Westphal, D Wolf, G Youngman, C Zeuner, W Zhou, JF Grabosch, HJ Kharchilava, A Leich, A Mari, SM Mattingly, MCK Meyer, A Schlenstedt, S Wulff, N Barbagli, G Gallo, E Pelfer, P Anzivino, G Maccarrone, G DePasquale, S Votano, L Bamberger, A Eisenhardt, S Freidhof, A SoldnerRembold, S Schroeder, J Trefzger, T Brook, NH Bussey, PJ Doyle, AT Saxon, DH Utley, ML Wilson, AS Dannemann, A Holm, U Horstmann, D Neumann, T Sinkus, R Wick, K Badura, E Burow, BD Hagge, L Lohrmann, E Milewski, J Nakahata, M Pavel, N Poelz, G Schott, W Zetsche, F Bacon, TC Bruemmer, N Butterworth, I Harris, VL Hung, BYH Long, KR Miller, DB Morawitz, PPO Prinias, A Sedgbeer, JK Whitfield, AF Mallik, U McCliment, E Wang, MZ Wang, SM Wu, JT Cloth, P Filges, D An, SH Hong, SM Nam, SW Park, SK Suh, MH Yon, SH Imlay, R Kartik, S Kim, HJ McNeil, RR Metcalf, W Nadendla, VK Barreiro, F Cases, G Fernandez, JP Graciani, R Hernandez, JM Hervas, L Labarga, L Martinez, M delPeso, J Puga, J Terron, J deTroconiz, JF Smith, GR Corriveau, F Hanna, DS Hartmann, J Hung, LW Lim, JN Matthews, CG Patel, PM Sinclair, LE Stairs, DG StLaurent, M Ullmann, R Zacek, G Bashkirov, V Dolgoshein, BA Stifutkin, A Bashindzhagyan, GL Ermolov, PF Gladilin, LK Golubkov, YA Kobrin, VD Krozhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Savin, AA Shcheglova, LM Solomin, AN Zotov, NP Botje, M Chlebana, F Dake, A Engelen, J deKamps, M Kooijman, P Kruse, A Tiecke, H Verkerke, W Vreeswijk, M Wiggers, L deWolf, E vanWoudenberg, R Acosta, D Bylsma, B Durkin, LS Gilmore, J Honscheid, K Li, C Ling, TY McLean, KW Nylander, P Park, IH Romanowski, TA Seidlein, R Bailey, DS Byrne, A Cashmore, RJ CooperSarkar, AM Devenish, RCE Harnew, N Lancaster, M Lindemann, L McFall, JD Nath, C Noyes, VA Quadt, A Tickner, JR Uijterwaal, H Walczak, R Waters, DS Wilson, FF Yip, T Abbiendi, G Bertolin, A Brugnera, R Carlin, R DalCorso, F DeGiorgi, M Dosselli, U Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Bulmahn, J Butterworth, JM Feild, RG Oh, BY Okrasinski, JR Whitmore, JJ DAgostini, G Marini, G Nigro, A Tassi, E Hart, JC McCubbin, NA Prytz, K Shah, TP Short, TL Barberis, E Dubbs, T Heusch, C VanHook, M Lockman, W Rahn, JT Sadrozinski, HFW Seiden, A Williams, DC Biltzinger, J Seifert, RJ Schwarzer, O Walenta, AH Zech, G Abramowicz, H Briskin, G Dagan, S HandelPikielny, C Levy, A Fleck, JI Hasegawa, T Hazumi, M Ishii, T Kuze, M Mine, S Nagasawa, Y Nakao, M Suzuki, I Tokushuku, K Yamada, S Yamazaki, Y Chiba, M Hamatsu, R Hirose, T Homma, K Kitamura, S Nakamitsu, Y Yamauchi, K Cirio, R Costa, M Ferrero, MI Lamberti, L Maselli, S Peroni, C Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Bandyopadhyay, D Benard, F Brkic, M Gingrich, DM Hartner, GF Joo, KK Levman, GM Martin, JF Orr, RS Polenz, S Sampson, CR Teuscher, RJ Catterall, CD Jones, JW Kaziewicz, PB Lane, JB Saunders, RL Shulman, J Blankenship, K Lu, B Mo, LW Bogusz, W Charchula, K Ciborowski, J Gajewski, J Grzelak, G Kasprzak, M Krzyzanowski, M Muchorowski, K Nowak, RJ Pawlak, JM Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Eisenberg, Y Karshon, U Revel, D ZerZion, D Ali, I Badgett, WF Behrens, B Dasu, S Fordham, C Foudas, C Goussiou, A Loveless, RJ Reeder, DD Silverstein, S Smith, WH Vaiciulis, A Wodarczyk, M Tsurugai, T Bhadra, S Cardy, ML Fagerstroem, CP Frisken, WR Furutani, KM Khakzad, M Murray, WN Schmidke, WB AF Derrick, M Krakauer, D Magill, S Mikunas, D Musgrave, B Repond, J Stanek, R Talaga, RL Zhang, H Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Bruni, P Romeo, GC Castellini, G Chiarini, M Cifarelli, L Cindolo, F Contin, A Corradi, M Gialas, I Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Nemoz, C Palmonari, F Polini, A Sartorelli, G Timellini, R Garcia, YZ Zichichi, A Bornheim, A Crittenden, J Desch, K Diekmann, B Doeker, T Eckert, M Feld, L Frey, A Geerts, M Grothe, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Katz, UF Mengel, S Mollen, J Paul, E Pfeiffer, M Rembser, C Schramm, D Stamm, J Wedemeyer, R CampbellRobson, S Cassidy, A Cottingham, WN Dyce, N Foster, B George, S Hayes, ME Heath, GP Heath, HF Morgado, CJS OMara, JA Piccioni, D Roff, DG Tapper, RJ Yoshida, R Rau, RR Arneodo, M Ayad, R Capua, M Garfagnini, A Iannotti, L Schioppa, M Susinno, G Bernstein, A Caldwell, A Cartiglia, N Parsons, JA Ritz, S Sciulli, F Straub, PB Wai, L Yang, S Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Piotrzkowski, K Zachara, M Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowalski, T Przybycien, M RulikowskaZarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Beier, H Bienlein, JK Coldewey, C Deppe, O Desler, K Drews, G Flasinski, M Gilkinson, DJ Glasman, C Gottlicher, P GrosseKnetter, J Gutjahr, B Haas, T Hain, W Hasell, D Hessling, H Iga, Y Johnson, KF Joos, P Kasemann, M Klanner, R Koch, W Kopke, L Kotz, U Kowalski, H Labs, J Ladage, A Lohr, B Lowe, M Luke, D Mainusch, J Manczak, O Monteiro, T Ng, JST Nickel, S Notz, D Ohrenberg, K Roco, M Rohde, M Roldan, J Schneekloth, U Schulz, W Selonke, F Stiliaris, E Surrow, B Voss, T Westphal, D Wolf, G Youngman, C Zeuner, W Zhou, JF Grabosch, HJ Kharchilava, A Leich, A Mari, SM Mattingly, MCK Meyer, A Schlenstedt, S Wulff, N Barbagli, G Gallo, E Pelfer, P Anzivino, G Maccarrone, G DePasquale, S Votano, L Bamberger, A Eisenhardt, S Freidhof, A SoldnerRembold, S Schroeder, J Trefzger, T Brook, NH Bussey, PJ Doyle, AT Saxon, DH Utley, ML Wilson, AS Dannemann, A Holm, U Horstmann, D Neumann, T Sinkus, R Wick, K Badura, E Burow, BD Hagge, L Lohrmann, E Milewski, J Nakahata, M Pavel, N Poelz, G Schott, W Zetsche, F Bacon, TC Bruemmer, N Butterworth, I Harris, VL Hung, BYH Long, KR Miller, DB Morawitz, PPO Prinias, A Sedgbeer, JK Whitfield, AF Mallik, U McCliment, E Wang, MZ Wang, SM Wu, JT Cloth, P Filges, D An, SH Hong, SM Nam, SW Park, SK Suh, MH Yon, SH Imlay, R Kartik, S Kim, HJ McNeil, RR Metcalf, W Nadendla, VK Barreiro, F Cases, G Fernandez, JP Graciani, R Hernandez, JM Hervas, L Labarga, L Martinez, M delPeso, J Puga, J Terron, J deTroconiz, JF Smith, GR Corriveau, F Hanna, DS Hartmann, J Hung, LW Lim, JN Matthews, CG Patel, PM Sinclair, LE Stairs, DG StLaurent, M Ullmann, R Zacek, G Bashkirov, V Dolgoshein, BA Stifutkin, A Bashindzhagyan, GL Ermolov, PF Gladilin, LK Golubkov, YA Kobrin, VD Krozhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Savin, AA Shcheglova, LM Solomin, AN Zotov, NP Botje, M Chlebana, F Dake, A Engelen, J deKamps, M Kooijman, P Kruse, A Tiecke, H Verkerke, W Vreeswijk, M Wiggers, L deWolf, E vanWoudenberg, R Acosta, D Bylsma, B Durkin, LS Gilmore, J Honscheid, K Li, C Ling, TY McLean, KW Nylander, P Park, IH Romanowski, TA Seidlein, R Bailey, DS Byrne, A Cashmore, RJ CooperSarkar, AM Devenish, RCE Harnew, N Lancaster, M Lindemann, L McFall, JD Nath, C Noyes, VA Quadt, A Tickner, JR Uijterwaal, H Walczak, R Waters, DS Wilson, FF Yip, T Abbiendi, G Bertolin, A Brugnera, R Carlin, R DalCorso, F DeGiorgi, M Dosselli, U Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Bulmahn, J Butterworth, JM Feild, RG Oh, BY Okrasinski, JR Whitmore, JJ DAgostini, G Marini, G Nigro, A Tassi, E Hart, JC McCubbin, NA Prytz, K Shah, TP Short, TL Barberis, E Dubbs, T Heusch, C VanHook, M Lockman, W Rahn, JT Sadrozinski, HFW Seiden, A Williams, DC Biltzinger, J Seifert, RJ Schwarzer, O Walenta, AH Zech, G Abramowicz, H Briskin, G Dagan, S HandelPikielny, C Levy, A Fleck, JI Hasegawa, T Hazumi, M Ishii, T Kuze, M Mine, S Nagasawa, Y Nakao, M Suzuki, I Tokushuku, K Yamada, S Yamazaki, Y Chiba, M Hamatsu, R Hirose, T Homma, K Kitamura, S Nakamitsu, Y Yamauchi, K Cirio, R Costa, M Ferrero, MI Lamberti, L Maselli, S Peroni, C Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Bandyopadhyay, D Benard, F Brkic, M Gingrich, DM Hartner, GF Joo, KK Levman, GM Martin, JF Orr, RS Polenz, S Sampson, CR Teuscher, RJ Catterall, CD Jones, JW Kaziewicz, PB Lane, JB Saunders, RL Shulman, J Blankenship, K Lu, B Mo, LW Bogusz, W Charchula, K Ciborowski, J Gajewski, J Grzelak, G Kasprzak, M Krzyzanowski, M Muchorowski, K Nowak, RJ Pawlak, JM Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Eisenberg, Y Karshon, U Revel, D ZerZion, D Ali, I Badgett, WF Behrens, B Dasu, S Fordham, C Foudas, C Goussiou, A Loveless, RJ Reeder, DD Silverstein, S Smith, WH Vaiciulis, A Wodarczyk, M Tsurugai, T Bhadra, S Cardy, ML Fagerstroem, CP Frisken, WR Furutani, KM Khakzad, M Murray, WN Schmidke, WB TI Rapidity gaps between jets in photoproduction at HERA SO PHYSICS LETTERS B LA English DT Article ID PARTON ELASTIC-SCATTERING; ZEUS BARREL CALORIMETER; MONTE-CARLO; EVENTS; CONSTRUCTION; COLLISIONS; DESIGN AB Photoproduction events which have two or more jets have been studied in the W-gamma P range 135 GeV < W-gamma P < 280 GeV with the ZEUS detector at HERA, A class of events is observed with little hadronic activity between the jets, The jets are separated by pseudorapidity intervals (Delta eta) Of up to four units and have transverse energies greater than 6 GeV. A gap is defined as the absence between the jets of particles with transverse energy greater than 300 MeV. The fraction of events containing a gap is measured as a function of Delta eta. It decreases exponentially as expected for processes in which colour is exchanged between the jets, up to a value of Delta eta similar to 3, then reaches a constant value of about 0.1. The excess above the exponential fall-off can be interpreted as evidence for hard diffractive scattering via a strongly interacting colour singlet object. C1 UNIV BOLOGNA, BOLOGNA, ITALY. IST NAZL FIS NUCL, BOLOGNA, ITALY. UNIV BONN, INST PHYS, W-5300 BONN, GERMANY. UNIV BRISTOL, HH WILLS PHYS LAB, BRISTOL BS8 1TL, AVON, ENGLAND. BROOKHAVEN NATL LAB, LONG ISLAND, NY USA. UNIV CALABRIA, DEPT PHYS, I-87036 COSENZA, ITALY. IST NAZL FIS NUCL, COSENZA, ITALY. COLUMBIA UNIV, NEVIS LABS, IRVINGTON, NY USA. INST NUCL PHYS, KRAKOW, POLAND. ACAD MIN & MET, FAC PHYS & NUCL TECHNIQUES, KRAKOW, POLAND. JAGIELLONIAN UNIV, DEPT PHYS, KRAKOW, POLAND. DEUTSCH ELEKTRONEN SYNCHOTRON DESY, HAMBURG, GERMANY. DESY ZEUTHEN, INST HOCHENERGIEPHYS, ZEUTHEN, GERMANY. UNIV FLORENCE, FLORENCE, ITALY. IST NAZL FIS NUCL, I-50125 FLORENCE, ITALY. IST NAZL FIS NUCL, LAB NAZL FRASCATI, I-00044 FRASCATI, ITALY. UNIV FREIBURG, FAK PHYS, W-7800 FREIBURG, GERMANY. UNIV GLASGOW, DEPT PHYS & ASTRON, GLASGOW, LANARK, SCOTLAND. UNIV HAMBURG, INST EXPTL PHYS 1, HAMBURG, GERMANY. UNIV HAMBURG, INST EXPTL PHYS 2, W-2000 HAMBURG, GERMANY. UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED, HIGH ENERGY NUCL PHYS GRP, LONDON, ENGLAND. UNIV IOWA, DEPT PHYS & ASTRON, IOWA CITY, IA 52242 USA. FORSCHUNGSZENTRUM JULICH, FORSCHUNGSZENTRUM, INST KERNPHYS, W-5170 JULICH, GERMANY. KOREA UNIV, SEOUL 136701, SOUTH KOREA. LOUISIANA STATE UNIV, DEPT PHYS & ASTRON, BATON ROUGE, LA 70803 USA. UNIV AUTONOMA MADRID, DEPT FIS TEOR, MADRID, SPAIN. UNIV MANITOBA, DEPT PHYS, WINNIPEG, MB R3T 2N2, CANADA. MCGILL UNIV, DEPT PHYS, MONTREAL, PQ, CANADA. MOSCOW MV LOMONOSOV STATE UNIV, INST NUCL PHYS, MOSCOW, RUSSIA. NIKHEF H, AMSTERDAM, NETHERLANDS. UNIV AMSTERDAM, AMSTERDAM, NETHERLANDS. OHIO STATE UNIV, DEPT PHYS, COLUMBUS, OH 43210 USA. UNIV OXFORD, DEPT PHYS, OXFORD, ENGLAND. UNIV PADUA, DIPARTIMENTO FIS, PADUA, ITALY. IST NAZL FIS NUCL, PADUA, ITALY. PENN STATE UNIV, DEPT PHYS, UNIVERSITY PK, PA 16802 USA. UNIV ROMA LA SAPIENZA, DIPARTIMENTO FIS, I-00185 ROME, ITALY. IST NAZL FIS NUCL, ROME, ITALY. RUTHERFORD APPLETON LAB, DIDCOT OX11 0QX, OXON, ENGLAND. UNIV CALIF SANTA CRUZ, SANTA CRUZ, CA 95064 USA. UNIV GESAMTHSCH SIEGEN, FACHBEREICH PHYS, W-5900 SIEGEN, GERMANY. TEL AVIV UNIV, SCH PHYS, IL-69978 TEL AVIV, ISRAEL. UNIV TOKYO, INST NUCL STUDY, TOKYO, JAPAN. TOKYO METROPOLITAN UNIV, DEPT PHYS, TOKYO, JAPAN. UNIV TURIN, DIPARTIMENTO FIS SPERIMENTALE, TURIN, ITALY. IST NAZL FIS NUCL, I-10125 TURIN, ITALY. TORINO UNIV, FAC SCI 2, ALESSANDRIA, ITALY. IST NAZL FIS NUCL, ALESSANDRIA, ITALY. UNIV TORONTO, DEPT PHYS, TORONTO, ON, CANADA. UCL, DEPT PHYS & ASTRON, LONDON, ENGLAND. VIRGINIA POLYTECH INST & STATE UNIV, DEPT PHYS, BLACKSBURG, VA 24061 USA. UNIV WARSAW, INST EXPTL PHYS, WARSAW, POLAND. INST NUCL STUDIES, PL-00681 WARSAW, POLAND. WEIZMANN INST SCI, PARTICLE PHYS DEPT, IL-76100 REHOVOT, ISRAEL. UNIV WISCONSIN, DEPT PHYS, MADISON, WI 53706 USA. MEIJI GAKUIN UNIV, FAC GEN EDUC, YOKOHAMA, KANAGAWA, JAPAN. YORK UNIV, DEPT PHYS, N YORK, ON M3J 1P3, CANADA. IROE, FLORENCE, ITALY. RP ARGONNE NATL LAB, 9700 S CASS AVE, ARGONNE, IL 60439 USA. RI Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Hernandez Calama, Jose Maria/H-9127-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016; Bashkirov, Vladimir/A-4818-2008; De Pasquale, Salvatore/B-9165-2008; Lancaster, Mark/C-1693-2008; Doyle, Anthony/C-5889-2009; Solomin, Anatoly/C-3072-2016; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; OI Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; Hernandez Calama, Jose Maria/0000-0001-6436-7547; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240; De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Graciani Diaz, Ricardo/0000-0001-7166-5198; Anzivino, Giuseppina/0000-0002-5967-0952; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Lancaster, Mark/0000-0002-8872-7292; Martinez Rodriguez, Manel/0000-0002-9763-9155; Utley, Martin/0000-0001-9928-1516; Chwastowski, Janusz/0000-0002-6190-8376 NR 39 TC 74 Z9 74 U1 0 U2 3 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 FEB 15 PY 1996 VL 369 IS 1 BP 55 EP 68 DI 10.1016/0370-2693(95)01588-4 PG 14 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA TW671 UT WOS:A1996TW67100008 ER PT J AU Baker, EN Blundell, TL Dodson, E Dodson, G Gilliland, GL Sussman, JL Vijayan, M AF Baker, EN Blundell, TL Dodson, E Dodson, G Gilliland, GL Sussman, JL Vijayan, M TI Diffraction data deposition SO STRUCTURE LA English DT Letter C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. WEIZMANN INST SCI,DEPT BIOL STRUCT,IL-76100 REHOVOT,ISRAEL. INDIAN INST SCI,MOLEC BIOPHYS UNIT,BANGALORE 560012,KARNATAKA,INDIA. MASSEY UNIV,DEPT CHEM & BIOCHEM,PALMERSTON NORTH,NEW ZEALAND. UNIV LONDON BIRKBECK COLL,DEPT CRYSTALLOG,IMPERIAL CANC RES FUND,STRUCT MOLEC BIOL UNIT,LONDON WC1E 7HX,ENGLAND. UNIV YORK,DEPT CHEM,YORK YO1 5DD,N YORKSHIRE,ENGLAND. CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. RP Baker, EN (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 0969-2126 J9 STRUCTURE JI Structure PD FEB 15 PY 1996 VL 4 IS 2 BP 217 EP 217 DI 10.1016/S0969-2126(96)00024-X PG 1 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA TW810 UT WOS:A1996TW81000010 PM 8805528 ER PT J AU Lippert, T Koskelo, A Stoutland, PO AF Lippert, T Koskelo, A Stoutland, PO TI Direct observation of a photoinduced Wolff rearrangement in PMMA using ultrafast infrared spectroscopy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DECOMPOSITION MECHANISMS; POLY(METHYL METHACRYLATE; LASER ABLATION; MELDRUMS DIAZO; EXCIMER LASER; PHOTOLYSIS; KETENE; ABINITIO; DIAZONAPHTHOQUINONES; PHOTORESISTS C1 LOS ALAMOS NATL LAB,DIV CHEM SCI & TECHNOL,LOS ALAMOS,NM 87545. RI Lippert, Thomas/N-2423-2016 NR 40 TC 26 Z9 26 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 14 PY 1996 VL 118 IS 6 BP 1551 EP 1552 DI 10.1021/ja9536429 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA TV706 UT WOS:A1996TV70600039 ER PT J AU Ghirardi, ML Lutton, TW Seibert, M AF Ghirardi, ML Lutton, TW Seibert, M TI Interactions between diphenylcarbazide, zinc, cobalt, and manganese on the oxidizing side of photosystem II SO BIOCHEMISTRY LA English DT Article ID PHOTOSYNTHETIC OXYGEN EVOLUTION; ELECTRON-TRANSFER REACTIONS; EVOLVING COMPLEX; D1 POLYPEPTIDE; BINDING SITE; DIRECTED MUTAGENESIS; MEMBRANE-FRAGMENTS; O2 EVOLUTION; MN; PHOTOINHIBITION AB The inhibition of DPC-mediated DCIP photoreduction by exogenous MnCl2 in Tris-treated photosystem II (PSII) membrane fragments has been used to probe for amino acids on the PSII reaction center proteins, including D1His337, that provide ligands for binding manganese [Preston, C., & Seibert, M. (1990) in Current Research in Photosynthesis (Baltscheffsky, M., Ed.) Vol. I, pp 925-928, Kluwer Academic Publishers. Dordrecht, The Netherlands; Preston, C., & Seibert, M. (1991) Biochemistry 30, 9615-9624 and 9625-9633]. At a concentration of 200 mu M, DPC is photooxidized at both a high-affinity and a low-affinity site in PSII at approximately the same initial rate. Addition of 10 mu M MnCl2 noncompetitively inhibits DPC photooxidation at the high-affinity site, with a K-i of 1.5 mu M, causing a decrease of about 50% in the overall DCIP photoreduction rate. The high-affinity site for Mn binding was deconvoluted into four independent components. In earlier work, the inhibition was attributed to the tight association of either Mn2+ or Mn3+ with the PSII membrane. We report here that inhibition of DPC photooxidation may involve two different types of high-affinity, Mn-binding components: (a) one that is specific for Mn, and (b) others that bind Mn, but may also bind additional divalent cations, such as Zn and Co, that are not photooxidized by PSII. These conclusions are based on the observations that (a) DPC photooxidation can be inhibited by Zn2+ and Co2+; (b) Zn2+ and Co2+ interact with Mn2+ in a nonmutually exclusive manner, suggesting that they may share some binding components with Mn2+; (c) high-affinity Mn2+ (but not Zn2+ or Co2+) inhibition of DPC photooxidation is accompanied by nondecaying fluorescence emission, following a single saturating flash, indicating efficient electron donation by Mn2+ to Y-z(+); (d) Mn2+ photooxidation in the presence of DPC is not inhibited by Zn2+ or Co2+; and (e) kinetic modeling of the interaction between high-affinity Mn2+ and DPC in PSII indicates inhibition of steady-state Mn2+ photooxidation by DPC, but allows for a single photooxidation of Mn2+. We conclude that Mn inhibition of DPC photooxidation can be used to identify Mn-binding sites of physiological importance, and suggest that the Mn-specific component of the high-affinity, Mn-binding site involves the ligand to the first Mn bound during photoactivation (i.e., Asp170 on D1, as found by other investigators). C1 NATL RENEWABLE ENERGY LAB,PHOTOCONVERS RES BRANCH,GOLDEN,CO 80401. NR 57 TC 42 Z9 43 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 13 PY 1996 VL 35 IS 6 BP 1820 EP 1828 DI 10.1021/bi951657d PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TV600 UT WOS:A1996TV60000015 PM 8639663 ER PT J AU Pechik, I Ji, XH Fidelis, K Karavitis, M Moult, J Brinigar, WS Fronticelli, C Gilliland, GL AF Pechik, I Ji, XH Fidelis, K Karavitis, M Moult, J Brinigar, WS Fronticelli, C Gilliland, GL TI Crystallographic, molecular modeling, and biophysical characterization of the Valine(beta 67) (E11)->threonine variant of hemoglobin SO BIOCHEMISTRY LA English DT Article ID SITE-DIRECTED MUTAGENESIS; SPERM WHALE MYOGLOBIN; SEQUENCE-SPECIFIC PROTEOLYSIS; RECOMBINANT HUMAN HEMOGLOBIN; DISTAL POCKET POLARITY; LIGAND-BINDING; ESCHERICHIA-COLI; X-RAY; HEME POCKET; MACROMOLECULAR STRUCTURES AB The crystal structure of the mutant deoxyhemoglobin in which the beta-globin Val(67)(E11) has been replaced with threonine [Fronticelli et al. (1993) Biochemistry 32, 1235-1242] has been determined at 2.2 Angstrom resolution. Prior to the crystal structure determination, molecular modeling indicated that the Thr(67)(E11) side chain hydroxyl group in the distal beta-heme pocket forms a hydrogen bond with the backbone carbonyl of His(63)(E7) and is within hydrogen-bonding distance of the N-delta of His(63)(E7). The mutant crystal structure indicates only small changes in conformation in the vicinity of the Ell mutation confirming the molecular modeling predictions. Comparison of the structures of the mutant beta-subunits and recombinant porcine myoglobin with the identical mutation [Cameron et al. (1993) Biochemistry 32, 13061-13070] indicates similar conformations of residues in the distal heme pocket, but there is no water molecule associated with either of the threonines of the beta-subunits. The introduction of threonine into the distal heme pocket, despite having only small perturbations in the local structure, has a marked affect on the interaction with ligands. In the oxy derivative there is a 2-fold decrease in O-2 affinity [Fronticelli et al. (1993) Biochemistry 32, 1235-1242], and the rate of autoxidation is increased by 2 orders of magnitude. In the CO derivative the IR spectrum shows modifications with respect to that of normal human hemoglobin, suggesting the presence of multiple CO conformers. In the nitrosyl derivative an interaction with the O-gamma atom of Thr(67)(E11) is probably responsible for the 10-fold increase in the rate of NO release from the beta-subunits. In the aquomet derivative there is a 6-fold decrease in the rate of hemin dissociation suggesting an interaction of the Fe-coordinated water with the O-gamma of Thr(67)(E11). C1 UNIV MARYLAND,SCH MED,DEPT BIOCHEM,BALTIMORE,MD 21201. UNIV MARYLAND,INST BIOTECHNOL,CTR ADV RES BIOTECHNOL,ROCKVILLE,MD 20850. NIST,ROCKVILLE,MD 20850. TEMPLE UNIV,DEPT CHEM,PHILADELPHIA,PA 19122. LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94551. RI Ji, Xinhua/C-9664-2012 OI Ji, Xinhua/0000-0001-6942-1514 FU NHLBI NIH HHS [HLBI-48517] NR 50 TC 17 Z9 17 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 13 PY 1996 VL 35 IS 6 BP 1935 EP 1945 DI 10.1021/bi9519967 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TV600 UT WOS:A1996TV60000029 PM 8639677 ER PT J AU BachrachAshkenasy, N Kronik, L Shapira, Y Rosenwaks, Y Hanna, MC Leibovitch, M Ram, P AF BachrachAshkenasy, N Kronik, L Shapira, Y Rosenwaks, Y Hanna, MC Leibovitch, M Ram, P TI Surface photovoltage spectroscopy of quantum wells and superlattices SO APPLIED PHYSICS LETTERS LA English DT Article ID HETEROSTRUCTURES; INTERFACES AB Surface photovoltage spectroscopy (SPS) has been employed to monitor optical transitions in quantum well and superlattice structures at room temperature. Excellent agreement is found between theoretical predictions of heavy hole and electron energy level positions and the observed transitions. The results show that using this technique, the complete band diagram of the quantum structure may be constructed. SPS emerges as a powerful tool capable of monitoring optical transitions above the lowest one in a simple to interpret, contactless, and nondestructive way. (C) 1996 American Institute of Physics. C1 NATL RENEWABLE ENERGY LAB,GOLDEN,CO 80401. CUNY BROOKLYN COLL,DEPT PHYS,BROOKLYN,NY 11210. RP BachrachAshkenasy, N (reprint author), TEL AVIV UNIV,DEPT PHYS ELECTR,FAC ENGN,IL-69978 RAMAT AVIV,ISRAEL. RI ASHKENASY, NURIT/F-1501-2012 NR 19 TC 30 Z9 31 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 12 PY 1996 VL 68 IS 7 BP 879 EP 881 DI 10.1063/1.116217 PG 3 WC Physics, Applied SC Physics GA TU828 UT WOS:A1996TU82800001 ER PT J AU Bindal, C Erdemir, A AF Bindal, C Erdemir, A TI Ultralow friction behavior of borided steel surfaces after flash annealing SO APPLIED PHYSICS LETTERS LA English DT Article ID ACID-FORMING SURFACES; TRIBOLOGICAL PROPERTIES; SELF-LUBRICATION; WEAR AB In this letter, we describe the ultralow friction mechanism of borided steel surfaces subjected to a short-duration, or ''flash,'' annealing procedure. In this procedure, a borided steel surface is exposed to high temperature (600 to 800 degrees C) for a short time (3 to 5 min) and then cooled to room temperature in open air. During the high-temperature exposure, boron atoms within the borided layer diffuse to the surface and react spontaneously with oxygen in air. The reaction product is a thin boron oxide film. During cooling, the boron oxide reacts spontaneously with moisture in the surrounding air to form a thin boric acid film. The sliding friction coefficient of a Si3N4, ball against this flash-annealed surface is about 0.06, but is 0.5 and higher against the unborided or borided-only surfaces. Mechanistically, we propose that the ultralow friction behavior of the borided and flash-annealed surface is due mainly to the layered-crystal structure of the boric acid film that forms on the sliding surface. (C) 1996 American Institute of Physics. C1 SAKARYA UNIV,DEPT ENGN MET,ADAPAZARI,TURKEY. RP Bindal, C (reprint author), ARGONNE NATL LAB,DIV ENERGY TECHNOL,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 15 TC 40 Z9 41 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 12 PY 1996 VL 68 IS 7 BP 923 EP 925 DI 10.1063/1.116232 PG 3 WC Physics, Applied SC Physics GA TU828 UT WOS:A1996TU82800016 ER PT J AU Biefeld, RM Allerman, AA Pelczynski, MW AF Biefeld, RM Allerman, AA Pelczynski, MW TI Growth of n- and p-type Al(As)Sb by metalorganic chemical vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID TRIMETHYLAMINE ALANE; PHASE EPITAXY AB AlSb and AlAsxSb1-x epitaxial films grown by metalorganic chemical vapor deposition were successfully doped p- or n-type using diethylzine or tetraethyltin, respectively. AlSb films were grown at 500 degrees C and 76 Torr using trimethylamine alane and triethylantimony. AlAs0.16Sb0.84 films lattice matched to InAs were grown at 600 degrees C and 76 Torr by adding arsine. Secondary ion mass spectroscopy showed C and O levels below 2x10(18) and 6x10(18) cm(-3), respectively, for undoped AlSb. Similar levels of O were found in AlAs0.16Sb0.84 films but C levels were an order of magnitude less in undoped and Sn-doped AlAS(0.16)Sb(0.84) films. Hall measurements of AlAs0.16Sb0.84 showed hole concentrations between 1x10(17) to 5x10(18) cm(-3) for Zn-doped material and electron concentrations in the low to mid- 10(18) cm(-3) for Zn-doped material. (C) 1996 American Institute of Physics. RP Biefeld, RM (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 14 TC 27 Z9 27 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 12 PY 1996 VL 68 IS 7 BP 932 EP 934 DI 10.1063/1.116235 PG 3 WC Physics, Applied SC Physics GA TU828 UT WOS:A1996TU82800019 ER PT J AU Helgesson, J Randrup, J AF Helgesson, J Randrup, J TI Treatment of pionic modes at the nuclear surface for transport descriptions SO NUCLEAR PHYSICS A LA English DT Article ID HEAVY-ION COLLISIONS AB Dispersion relations and amplitudes of collective pionic modes are derived in a pi + NN-1 + Delta M(-1) model for use in transport descriptions by means of a local density approximation. It is discussed how pionic modes can be converted to real particles when penetrating the nuclear surface and how earlier treatments can be improved. When the surface is stationary only free pions emerge. The time-dependent situation is also addressed, as is the conversion of non-physical (i.e. unperturbed Delta N-1) modes to real particles when the nuclear density vanishes. A simplified one-dimensional scenario is used to investigate the reflection and transmission of pionic modes at the nuclear surface. It is found that reflection of pionic modes is rather unlikely, but the process can be incorporated into transport descriptions by the use of approximate local transmission coefficients. RP Helgesson, J (reprint author), UNIV CALIF BERKELEY, LAWRENCE BERKELEY LAB, DIV NUCL SCI, BERKELEY, CA 94720 USA. NR 13 TC 9 Z9 9 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 FEB 12 PY 1996 VL 597 IS 4 BP 672 EP 700 DI 10.1016/0375-9474(95)00433-5 PG 29 WC Physics, Nuclear SC Physics GA TY635 UT WOS:A1996TY63500010 ER PT J AU Blanpied, G Blecher, M Caracappa, A Djalali, C Giordano, G Hicks, K Hoblit, S Khandaker, M Kistner, OC Matone, G Miceli, L Molinari, C Preedom, B Rebreyend, D Sandorfi, AM Schaerf, C Sealock, RM Stroher, H Thorn, CE Thornton, ST Whisnant, CS Zhang, H Zhao, X AF Blanpied, G Blecher, M Caracappa, A Djalali, C Giordano, G Hicks, K Hoblit, S Khandaker, M Kistner, OC Matone, G Miceli, L Molinari, C Preedom, B Rebreyend, D Sandorfi, AM Schaerf, C Sealock, RM Stroher, H Thorn, CE Thornton, ST Whisnant, CS Zhang, H Zhao, X TI Polarized compton scattering from the proton SO PHYSICAL REVIEW LETTERS LA English DT Article ID MODEL; ENERGIES; REGION AB New precision measurements of cross sections and polarization asymmetries in thr p(<(gamma)over bar>,gamma p) reaction at 90 degrees c.m. are presented for incident energies between 213 and 333 MeV. A long-standing problem with earlier experiments that appeared to violate unitarity at the peak of the Delta is resolved. Data are compared to theories based on baryon resonance structure and to dispersion relations. Recent calculations using the proton polarizabilities are closest to the data, although inconsistencies are observed near the Delta resonance. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. IST NAZL FIS NUCL,LAB NAZL FRASCATI,I-00044 FRASCATI,ITALY. UNIV ROMA TOR VERGATA,ROME,ITALY. IST NAZL FIS NUCL,SEZ ROMA 2,ROME,ITALY. UNIV VIRGINIA,DEPT PHYS,CHARLOTTESVILLE,VA 22901. VIRGINIA POLYTECH INST & STATE UNIV,DEPT PHYS,BLACKSBURG,VA 24061. OHIO UNIV,DEPT PHYS,ATHENS,OH 45701. UNIV GIESSEN,INST PHYS 2,W-6300 GIESSEN,GERMANY. UNIV GENOA,I-16146 GENOA,ITALY. IST NAZL FIS NUCL,SEZ GENOVA,I-16146 GENOA,ITALY. RP Blanpied, G (reprint author), UNIV S CAROLINA,DEPT PHYS,COLUMBIA,SC 29208, USA. OI Giordano, Gianfranco/0000-0001-7731-3142 NR 31 TC 39 Z9 39 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 12 PY 1996 VL 76 IS 7 BP 1023 EP 1026 DI 10.1103/PhysRevLett.76.1023 PG 4 WC Physics, Multidisciplinary SC Physics GA UB363 UT WOS:A1996UB36300005 ER PT J AU Elliott, SR Beiersdorfer, P Chen, MH AF Elliott, SR Beiersdorfer, P Chen, MH TI Trapped-ion technique for measuring the nuclear charge radii of highly charged radioactive isotopes SO PHYSICAL REVIEW LETTERS LA English DT Article ID LASER SPECTROSCOPY; SPECTROMETER; URANIUM; STATES; SHIFT AB We present the first measurement to isolate the variation of nuclear effects in the x-ray transitions of few-electron heavy ions. Using a novel technique to produce and trap radioactive ions we measured the energy difference between 2s(1/2)-2p(3/2) transitions in Li-, Be-. B-, and C-like U-233 and U-238. We show that because of the simplified atomic structure of few-electron ions the data are readily interpreted in terms of the variation in the mean nuclear radius. A value delta[r(2)](233.238) = -0.457 = 0.043 fm(2) is found, which lies between earlier measurements based on different techniques. C1 LAWRENCE LIVERMORE NATL LAB,DEPT PHYS & SPACE TECHNOL,LIVERMORE,CA 94550. RP Elliott, SR (reprint author), UNIV WASHINGTON,DEPT PHYS,POB 351560,SEATTLE,WA 98195, USA. NR 27 TC 29 Z9 29 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 FEB 12 PY 1996 VL 76 IS 7 BP 1031 EP 1034 DI 10.1103/PhysRevLett.76.1031 PG 4 WC Physics, Multidisciplinary SC Physics GA UB363 UT WOS:A1996UB36300007 ER PT J AU Chang, ZY Budny, RV Chen, L Darrow, D Fredrickson, ED Janos, A Mansfield, D Mazzucato, E McGuire, KM Nazikian, R Rewoldt, G Strachan, JD Tang, WM Taylor, G White, RB Zweben, S AF Chang, ZY Budny, RV Chen, L Darrow, D Fredrickson, ED Janos, A Mansfield, D Mazzucato, E McGuire, KM Nazikian, R Rewoldt, G Strachan, JD Tang, WM Taylor, G White, RB Zweben, S TI First observation of alpha particle loss induced by kinetic ballooning modes in TFTR deuterium-tritium experiments SO PHYSICAL REVIEW LETTERS LA English DT Article ID TOKAMAKS; GEOMETRY; PLASMAS; IONS AB A correlation between the measured alpha particle loss and high frequency (similar to 100-200 kHz) magnetohydrodynamic (MHD) modes has been observed in some high beta (= plasma pressure/magnetic pressure) DT plasmas in TFTR. These modes are localized around the peak plasma. pressure gradient and have ballooning characteristics. Particle simulation shows that the loss is due to wave-particle resonances. Linear instability analysis indicates that the plasma is unstable to the kinetic MHD ballooning modes driven by strong local pressure gradients. C1 UNIV CALIF IRVINE,DEPT PHYS,IRVINE,CA 92717. RP Chang, ZY (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. RI White, Roscoe/D-1773-2013 OI White, Roscoe/0000-0002-4239-2685 NR 20 TC 24 Z9 24 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 12 PY 1996 VL 76 IS 7 BP 1071 EP 1074 DI 10.1103/PhysRevLett.76.1071 PG 4 WC Physics, Multidisciplinary SC Physics GA UB363 UT WOS:A1996UB36300017 ER PT J AU Frank, M Mears, CA Labov, SE Azgui, F Lindeman, MA Hiller, LJ Netel, H Barfknecht, A AF Frank, M Mears, CA Labov, SE Azgui, F Lindeman, MA Hiller, LJ Netel, H Barfknecht, A TI High-resolution X-ray detectors with high-speed SQUID readout of superconducting tunnel junctions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern AB We present our first results obtained using new high-speed SQUID systems for the readout of normal conductor/insulator/ superconductor (NIS) and superconductor/insulator/superconductor (SIS) tunnel junctions. With an NIS device measured with a HYPRES SQUID we have achieved an energy resolution of 100 eV (FWHM) for 5.89 keV X-rays and an electronic noise of 40 eV at an operating temperature of 80 mK. With an SIS sensor at 200 mK and the same readout we have achieved an energy resolution of 29 eV (FWHM) at 5.89 keV and an electronic noise of 10 eV. C1 UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. CONDUCTUS INC,SUNNYVALE,CA 94086. RP Frank, M (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,DEPT PHYS,POB 808,L-401,LIVERMORE,CA 94550, USA. RI Frank, Matthias/O-9055-2014 NR 8 TC 56 Z9 56 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 FEB 11 PY 1996 VL 370 IS 1 BP 41 EP 43 DI 10.1016/0168-9002(95)01044-0 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400014 ER PT J AU Netel, H Frank, M Labov, SE Campbell, GH Mears, CA Brunet, E Hiller, LJ Lindeman, MA AF Netel, H Frank, M Labov, SE Campbell, GH Mears, CA Brunet, E Hiller, LJ Lindeman, MA TI Development of a prototype superconducting X-ray spectrometer using a Ta crystal as an absorber SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID QUASIPARTICLE; DETECTORS AB Superconducting tunnel junctions can be used as high resolution X-ray and gamma-ray spectrometers. Until recently, most results were from detectors that consisted of niobium and aluminium thin films deposited on insulating substrates. Typically Nb films with thicknesses of several hundred nanometers are used as absorbers. These thin-film devices inherently suffer from poor quantum efficiency. To increase this efficiency a foil or a single crystal can be used as the superconducting absorber. We are working on using ultra-pure, high-Z superconducting crystals as the X-ray and gamma-ray absorbers. We are developing a prototype detector with a 10 mu m-thick Ta crystal as an absorber, which will have a quantum efficiency of greater than 99% at 6 keV. In this paper we present several of the design and fabrication issues involved in assembling the a prototype superconducting crystal X-ray spectrometer. RP Netel, H (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,DEPT PHYS,7000 EAST AVE,POB 808,L-401,LIVERMORE,CA 94550, USA. RI Campbell, Geoffrey/F-7681-2010; Frank, Matthias/O-9055-2014 NR 14 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 47 EP 49 DI 10.1016/0168-9002(95)01045-9 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400016 ER PT J AU Mears, CA Labov, SE Frank, M Lindeman, MA Hiller, LJ Netel, H Barfknecht, AT AF Mears, CA Labov, SE Frank, M Lindeman, MA Hiller, LJ Netel, H Barfknecht, AT TI Analysis of pulse shape from a high-resolution superconducting tunnel junction X-ray spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID DETECTORS AB Superconducting-insulating-superconducting (SIS) tunnel junctions coupled to superconducting absorbers may be used as high-resolution, high-efficiency X-ray spectrometers. Until recently, the X-ray-induced current pulse from such devices has been measured using FET-based negative-feedback charge or current amplifiers. The limited bandwidth and feed-back nature of these amplifiers have made it difficult to deduce the true shape of the X-ray induced current pulse. Recently, we have begun to use high-bandwidth amplifiers based on Superconducting Quantum Interference Devices (SQUIDS) to measure the current pulses from our tunnel junction X-ray spectrometers. We have measured pulses from devices with niobium X-ray absorbing layers coupled to aluminum layers that serve as quasiparticle traps. We present here a study of pulse shape as a function of bias voltage. In general, the X-ray induced pulses increase in amplitude and become longer as we increase the bias voltage. We found that it is possible to differentiate pulses produced by X-ray absorption in the top niobium film from those produced in the bottom niobium film by measuring the rise time of the current pulses. This allows us to produce a high resolution spectrum using only pulses produced in the bottom niobium film. The measured energy resolution of this spectrum is 29 eV FWHM at 5.89 keV, about 5 times better than that obtainable using semiconductor ionization detectors. C1 CONDUCTUS INC,SUNNYVALE,CA 94086. UNIV CALIF DAVIS LIVERMORE,DEPT APPL SCI,LIVERMORE,CA. RP Mears, CA (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,L-401,7000 EAST AVE,POB 808,LIVERMORE,CA 94550, USA. RI Frank, Matthias/O-9055-2014 NR 10 TC 67 Z9 67 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 53 EP 56 DI 10.1016/0168-9002(95)01047-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400018 ER PT J AU Chow, D Neuhauser, B Frank, M Mears, CA Abusaidi, R Cunningham, M Golzarian, RM Hake, DD Labov, SE Lindeman, MA Owens, WE Sadoulet, B Slepoy, A AF Chow, D Neuhauser, B Frank, M Mears, CA Abusaidi, R Cunningham, M Golzarian, RM Hake, DD Labov, SE Lindeman, MA Owens, WE Sadoulet, B Slepoy, A TI Characterization of photolithographically defined NIS tunnel junctions as X-ray sensors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern AB We are developing normal-insulator-superconductor (NIS) tunnel junctions for use as X-ray detectors for astronomical purposes and as phonon sensors for dark matter detectors. We are using photolithographic techniques to produce structures in which aluminum is the superconductor, Al2O3 is the tunnel barrier, and copper is the normal metal. We describe microfabrication details and present X-ray pulse data. C1 SAN FRANCISCO STATE UNIV,DEPT PHYS & ASTRON,THIN FILM LAB,SAN FRANCISCO,CA 94132. UNIV CALIF BERKELEY,NSF CTR PARTICLE ASTROPHYS,BERKELEY,CA 94720. LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,LIVERMORE,CA 94550. RI Frank, Matthias/O-9055-2014 NR 5 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 57 EP 60 DI 10.1016/0168-9002(95)01048-3 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400019 ER PT J AU Sadoulet, B AF Sadoulet, B TI Comparison between phonon detection schemes SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern AB A number of schemes are being developed to detect phonons produced by particle by particle interactions in insulating crystals: heavily doped semiconductors, superconducting transition edge sensors in various bias modes, SIN junctions, and SIS junctions coupled with superconducting films. A theoretical comparison of the ultimate resolution of these schemes is attempted. This analysis is based on the known performance and limitations of these schemes, the physical processes involved (e.g., collection time of the phonons) and the standard theory of optimal filtering. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,DEPT PHYS,BERKELEY,CA 94720. NR 9 TC 1 Z9 1 U1 1 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 FEB 11 PY 1996 VL 370 IS 1 BP 61 EP 64 DI 10.1016/0168-9002(95)01049-1 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400020 ER PT J AU Labov, SE Mears, CA Frank, M Hiller, LJ Netel, H Lindeman, MA AF Labov, SE Mears, CA Frank, M Hiller, LJ Netel, H Lindeman, MA TI Assessment of low temperature X-ray detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID THERMAL DETECTORS; RESOLUTION; SPECTROSCOPY; ENERGY AB X-ray detectors operating at temperatures below 1 K can provide high spectral resolution over a large bandpass with high efficiency. A number of different approaches to low-temperature X-ray detectors have been developed using a wide range of X-ray absorbing materials, sensor systems and amplifiers. These devices will provide new capabilities for basic research in many fields ranging from biophysics to astrophysics, as well as improved sensitivity for commercial materials analysis systems. We derive figures of merit for some applications of these detectors. We then discuss the operating principles of several different detector systems, as well as the factors limiting performance. A summary of the performance that has been achieved in some devices is presented, followed by a summary what might be achievable in the near future. RP Labov, SE (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,7000 EAST AVE,POB 808,L-401,LIVERMORE,CA 94550, USA. RI Frank, Matthias/O-9055-2014 NR 21 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 FEB 11 PY 1996 VL 370 IS 1 BP 65 EP 68 DI 10.1016/0168-9002(95)01050-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400021 ER PT J AU Hiller, LJ Labov, SE Mears, CA Netel, H Frank, M Lindeman, MA AF Hiller, LJ Labov, SE Mears, CA Netel, H Frank, M Lindeman, MA TI A superconducting tunnel junction X-ray detector design for practical applications SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID RESOLUTION; ENERGY AB Superconducting tunnel junctions coupled to a superconducting absorber can be used as a high-resolution energy-dispersive X-ray detector. The energy of an absorbed X-ray breaks Cooper pairs in the absorber, producing quasiparticles. These quasiparticles can tunnel through the barrier and be counted. When used in conjunction with FET electronics, however, the noise requirements limit the area of the tunnel junction. In many designs, this also limits the absorber area. We present a detector design that separates the absorber from the junction. It features a tantalum absorber for high absorption efficiency and an aluminum transport layer for rapid, low loss transport to the junction. Transport is aided by multiple trapping stages, while fabrication is simplified by using only two materials. C1 UNIV CALIF DAVIS LIVERMORE,LIVERMORE,CA. RP Hiller, LJ (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,7000 EAST AVE,L-401,POB 808,LIVERMORE,CA 94550, USA. RI Frank, Matthias/O-9055-2014 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 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 81 EP 84 DI 10.1016/0168-9002(95)01056-4 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400026 ER PT J AU Azgui, F Mears, CA Labov, SE Frank, M Sadoulet, B Lindeman, M Golwala, S Hiller, LJ Netel, H AF Azgui, F Mears, CA Labov, SE Frank, M Sadoulet, B Lindeman, M Golwala, S Hiller, LJ Netel, H TI Non-equilibrium normal metal superconducting tunnel junction detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern AB Measurements of a Normal metal-Insulating-Superconducting (NIS) tunnel junction sensor Ag/AlOx/Al coupled to a thick Pb absorber are presented. All films were thermally deposited on a Si3N4 membrane using a shadow-mask technique. Irradiation experiments with a Fe-55 source were performed using a high bandwidth SQUID with one junction only. We observe a strong position dependence of the pulse shape and amplitude. The different classes of events are probably related to different elements of the sensor. At a bath temperature of 80 mK we have obtained for the main Mn K-alpha peak an energy resolution of 100 eV FWHM. We have preliminary evidence for absorption in the lead and efficient trapping of the resulting quasiparticles on the NIS normal electrode. C1 LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,LIVERMORE,CA 94550. UNIV STHB,INST PHYS,ALGIERS,ALGERIA. RP Azgui, F (reprint author), UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,301 LE CONTE HALL,BERKELEY,CA 94720, USA. RI Frank, Matthias/O-9055-2014 NR 5 TC 2 Z9 2 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 FEB 11 PY 1996 VL 370 IS 1 BP 121 EP 123 DI 10.1016/0168-9002(95)01112-9 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400040 ER PT J AU Shutt, T Akerib, DS Barnes, PD Cummings, A DaSilva, A Diaz, R Emes, J Golwala, SR Haller, EE Itoh, K Knowlton, B Quiennec, F Ross, RR Sadoulet, B Seitz, D Smith, G Stockwell, W Trumbull, T Therrien, R White, S Young, BA AF Shutt, T Akerib, DS Barnes, PD Cummings, A DaSilva, A Diaz, R Emes, J Golwala, SR Haller, EE Itoh, K Knowlton, B Quiennec, F Ross, RR Sadoulet, B Seitz, D Smith, G Stockwell, W Trumbull, T Therrien, R White, S Young, BA TI Recent results with a 62 g Ge cryogenic dark matter detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID GERMANIUM; PHONON; 20-MK AB We report on recent results with a 62 g Ge cryogenic detector that combines simultaneous ionization and phonon measurements to allow rejection of radioactive background in a dark matter experiment. This detector has FWHM baseline resolutions of 500 eV in phonons and 1200 eV in ionization. A simplified charge collection scheme has been employed to improve the efficiency of the background rejection. Based on the success of this detector we are currently building six 165 g detectors as part of the CDMS experiment. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV BRITISH COLUMBIA,DEPT PHYS,VANCOUVER,BC V6T 1Z1,CANADA. SANTA CLARA UNIV,DEPT PHYS,SANTA CLARA,CA 95053. RP Shutt, T (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,CTR PARTICLE ASTROPHYS,301 LE CONTE HALL,BERKELEY,CA 94720, USA. RI Itoh, Kohei/C-5738-2014 NR 7 TC 11 Z9 11 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 FEB 11 PY 1996 VL 370 IS 1 BP 165 EP 167 DI 10.1016/0168-9002(95)01367-9 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400055 ER PT J AU Barnes, PD DaSilva, A Akerib, DS Bauer, D Brink, P Cabrera, B Caldwell, DO Chugg, B Clarke, RM Cummings, A Davies, A Diaz, RC Dougherty, BL Emes, J Golwala, SR Hale, D Haller, EE Irwin, KD Knowlton, WB Kuziminov, V Lu, A Nam, SW Penn, MJ Novikov, V Pritychenko, BV Queinnec, F Ross, RR Sadoulet, B Seitz, D Shutt, T Smith, A Smith, G Sonnenschein, A Stockwell, W Taylor, JD Therrien, R Trumbull, TL White, S Wolgast, RC Yellin, S Young, BA AF Barnes, PD DaSilva, A Akerib, DS Bauer, D Brink, P Cabrera, B Caldwell, DO Chugg, B Clarke, RM Cummings, A Davies, A Diaz, RC Dougherty, BL Emes, J Golwala, SR Hale, D Haller, EE Irwin, KD Knowlton, WB Kuziminov, V Lu, A Nam, SW Penn, MJ Novikov, V Pritychenko, BV Queinnec, F Ross, RR Sadoulet, B Seitz, D Shutt, T Smith, A Smith, G Sonnenschein, A Stockwell, W Taylor, JD Therrien, R Trumbull, TL White, S Wolgast, RC Yellin, S Young, BA TI Installation of the Cryogenic Dark Matter Search (CDMS) SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID UNIVERSE; LIMITS AB We discuss the status of a cryogenic dark matter search beginning operation in the Stanford Underground Facility. The detectors will be cooled in a specially designed cryostat connected to a modified side access Oxford 400 dilution refrigerator. We discuss two detector designs and performance, the cryostat construction and operation, and the multi-level shield surrounding the cryostat. Finally, we will examine the limits which we will be able to set on WIMP dark matter with this experiment. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV BRITISH COLUMBIA,DEPT PHYS,VANCOUVER,BC V5Z 1M9,CANADA. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. CALTECH,JET PROP LAB,PASADENA,CA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RUSSIAN ACAD SCI,INST NUCL RES,BAKSAN NEUTRINO OBSERV,MOSCOW,RUSSIA. CARLETON UNIV,CRPP,OTTAWA,ON K1S 5B6,CANADA. MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824. UNIV SANTA CLARA,DEPT PHYS,SANTA CLARA,CA 95053. RP Barnes, PD (reprint author), UNIV CALIF BERKELEY,CTR PARTICLE ASTROPHYS,301 LE CONTE HALL,BERKELEY,CA 94720, USA. NR 19 TC 30 Z9 30 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 233 EP 236 DI 10.1016/0168-9002(95)01094-7 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400079 ER PT J AU Meier, J Chulkov, L Egelhof, P Fischer, C Henning, W vonKienlin, A Kirchner, G Kraus, G Weinbach, A AF Meier, J Chulkov, L Egelhof, P Fischer, C Henning, W vonKienlin, A Kirchner, G Kraus, G Weinbach, A TI Application of low temperature calorimeters for the detection of energetic heavy ions SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Workshop on Low Temperature Detectors (LTD6) CY AUG 28-SEP 01, 1995 CL BEATENBERG, SWITZERLAND SP Beer Brawand Fdn, Bern ID GIANT-RESONANCES; EXCITATION AB The energy sensitive detection of energetic heavy ions with calorimetric low temperature detectors is investigated. The temperature readout was done with an aluminum transition edge thermometer operated at T approximate to 1.5 K. For Ne-20-ions with an energy of E = 100 MeV/u from the SIS accelerator at GSI Darmstadt the best energy resolution obtained was Delta E/E = 1.9 X 10(-3). This value corresponds to the energy spread of the ion beam of the SIS. In a first application of such detectors the excitation of the giant resonance in lead nuclei via the reaction Pb-nat(Ne-20, Ne-20')Pb-nat* was investigated by separating inelastically from elastically scattered Ne-20-ions in the energy spectrum. At a scattering angle Theta(Lab) = 3 degrees the excitation energy and the strength of the giant resonance were found to be in good agreement with theoretical predictions. In a first test with an extracted cooled U-238-beam with an energy of E = 360 MeV/u from the storage ring ESR with an intrinsic beam energy spread of Delta E/E less than or equal to 2 X 10(-4) an energy resolution of Delta E = 97 MeV (Delta E/E = 1.1 X 10(-3)) was measured. The baseline noise was Delta E = 17 MeV. Further improvement of the energy resolution seems possible. C1 UNIV MAINZ,INST PHYS,D-55099 MAINZ,GERMANY. ARGONNE NATL LAB,ARGONNE,IL 60431. RP Meier, J (reprint author), GESELL SCHWERIONENFORSCH MBH,POSTFACH 110552,D-64220 DARMSTADT,GERMANY. NR 9 TC 19 Z9 19 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1996 VL 370 IS 1 BP 259 EP 262 DI 10.1016/0168-9002(95)01104-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA UA324 UT WOS:A1996UA32400087 ER PT J AU Colombi, S Dodelson, S Widrow, LM AF Colombi, S Dodelson, S Widrow, LM TI Large-scale structure tests of warm dark matter SO ASTROPHYSICAL JOURNAL LA English DT Review DE cosmology, theory; dark matter; large-scale structure of universe; methods, numerical ID GRAVITATIONAL-INSTABILITY; NEUTRINO OSCILLATIONS; DENSITY-FLUCTUATIONS; COSMOLOGICAL BOUNDS; VELOCITY DISPERSION; DOMINATED UNIVERSE; MASSIVE NEUTRINOS; GALAXY REDSHIFTS; CFA SURVEY; CONSTRAINTS AB The nature of the dark matter critically affects the large-scale structure of the universe. Under the assumptions that the universe is spatially flat with zero cosmological constant and that primordial perturbations were adiabatic with a Harrison-Zeldovich spectrum, neither hot dark matter (HDM) nor cold dark matter (CDM) appears consistent with the observed large-scale structure. Warm dark matter (WDM) is an intriguing alternative from the point of view of both cosmology and particle physics. We consider a one-parameter family of WDM models. The linear power spectra for these models is calculated and compared with the corresponding spectra for CDM, HDM, and mixed dark matter (MDM), as well as the power spectrum derived from observations. Our linear analyses suggest that a model universe dominated by a particle whose mass-to-temperature ratio m(x)/T-x is increased by a factor of 2 as compared with the standard HDM neutrino gives a reasonable fit to the data on large (>8 h(-1) Mpc) scales. N-body simulations for this particular WDM model show features of both HDM and CDM. As in HDM, the first objects to collapse are large pancake-like structures. The final matter distribution is rather smooth, and structures as small as galaxy halos are excluded. However, there appear to be virialized rich clusters evident in the CDM but not in the HDM simulations. Unfortunately, a simple comparison of the matter distribution and its statistical properties with observations indicates that WDM, like CDM, has too much power at small scales. This is particularly evident in the small-scale pairwise velocity dispersion. The cluster multiplicity function has the wrong shape, with too many rich clusters being produced, although this conclusion is based on the simple assumption that light traces mass in groups of galaxies. C1 QUEENS UNIV,DEPT PHYS,KINGSTON,ON K7L 3N6,CANADA. RP Colombi, S (reprint author), FERMILAB NATL ACCELERATOR LAB,NASA,FERMILAB ASTROPHYS CTR,BATAVIA,IL 60510, USA. NR 105 TC 118 Z9 118 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1996 VL 458 IS 1 BP 1 EP 17 DI 10.1086/176788 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500001 ER PT J AU Bennett, DP Rhie, SH AF Bennett, DP Rhie, SH TI Is there evidence for repeating gamma-ray bursters in the BASTE data? SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays, bursts; gamma rays, observations; methods, statistical AB The possibility that classical gamma-ray bursts (GRBs) occasionally repeat from the same locations on the sky provides a critical test of GRB models. There is currently some controversy about whether there is evidence for burst repetition in the Burst and Transient Source Experiment (BATSE) data. We introduce a gamma-ray burst ''pair-matching'' statistic that can be used to search-for a repeater signal in the BATSE data. The pair-matching statistic is built upon the reported position errors for each burst and is more sensitive than previously used statistics at detecting faint repeating bursts or multiple burst recurrences. It is also less likely to produce (false) evidence of burst repetition due to correlations in the positions that are inconsistent with repeating bursters. We find that the excesses in ''matched'' and ''antipodal'' pairs seen with other statistics are caused by an excess of pairs with a separation smaller than their error bars would indicate. When we consider all separations consistent with the error bars, no significant signal remains. We conclude that the publicly available BATSE 1B and 2B data sets contain no evidence for repeating gamma-ray bursters. C1 LAWRENCE LIVERMORE NATL LAB, INST GEOPHYS & PLANETARY PHYS, LIVERMORE, CA 94551 USA. RP Bennett, DP (reprint author), UNIV CALIF BERKELEY, CTR PARTICLE ASTROPHYS, BERKELEY, CA 94720 USA. RI Bennett, David/O-2136-2013 OI Bennett, David/0000-0001-8043-8413 NR 17 TC 10 Z9 10 U1 0 U2 0 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 FEB 10 PY 1996 VL 458 IS 1 BP 293 EP 300 DI 10.1086/176812 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TT075 UT WOS:A1996TT07500025 ER PT J AU Wood, DM Zunger, A Gershoni, D AF Wood, DM Zunger, A Gershoni, D TI Origins of k center dot p errors for [001] GaAs/AlAs heterostructures SO EUROPHYSICS LETTERS LA English DT Article ID ELECTRONIC-STRUCTURE; APPROXIMATION AB The k . p method + envelope function combination used for semiconductor heterostructures is based on approximations dubious under some conditions. We directly compare 8-band k . p with pseudopotential results for [001] GaAs/AlAs superlattices and quantum wells with all k . p input parameters directly computed from bulk GaAs and AlAs pseudopotential bands. We find generally very good agreement for zone-center hole states within similar to 200 meV of the GaAs valence band maximum, but i) systematic errors deeper in the valence band and ii) qualitative errors for even the lowest conduction bands with appreciable contributions from off-Gamma zinc-blende states. We trace these errors to inadequate k . p description of bulk GaAs and AlAs band dispersion away from the zone center. C1 TECHNION ISRAEL INST TECHNOL, DEPT PHYS, IL-32000 HAIFA, ISRAEL. RP NATL RENEWABLE ENERGY LAB, GOLDEN, CO 80401 USA. RI Zunger, Alex/A-6733-2013; OI Gershoni, David/0000-0002-3039-9919 NR 21 TC 8 Z9 8 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD FEB 10 PY 1996 VL 33 IS 5 BP 383 EP 389 DI 10.1209/epl/i1996-00351-x PG 7 WC Physics, Multidisciplinary SC Physics GA TX241 UT WOS:A1996TX24100009 ER PT J AU Durham, WB Stern, LA Kirby, SH AF Durham, WB Stern, LA Kirby, SH TI Rheology of water ices V and VI SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID GANYMEDE; EVOLUTION; CALLISTO AB We have measured the mechanical strength (sigma) of pure water ices V and VI under steady state deformation conditions. Constant displacement rate compressional tests were conducted in a gas apparatus at confining pressures from 400 < P < 800 MPa, temperatures from 209 < T < 270 K, and strain rates 7 x 10(-7) < epsilon < 7 x 10(-4) s(-1). Most of the results fit to an empirical flow law of the form epsilon = A sigma(n) exp (-(E* + PV*)/RT), where the four material constants A, n, E*, and V* are (for epsilon in inverse seconds and P and cr in megapascals) 10(23.0), 6.0, 136 kJ/mol, and 29 cm(3)/mol, respectively, for ice V; and 10(6.7), 4.5, 66 kJ/mol, and 11 cm(3)/mol, respectively, for ice VI. Ice VI may weaken to a mechanism of higher E* at T > 250 K. Ices V and VI are thus theologically distinct but by coincidence have approximately the same strength under the conditions chosen for these experiments. To avoid misidentification, these tests are therefore accompanied by careful observations of the occurrences and characteristics of phase changes. One sample each of ice V and VI was quenched at pressure to metastably retain the high-pressure phase and the acquired deformation microstructures; X ray diffraction analysis of these samples confirmed the phase identification. Surface replicas of the deformed and quenched samples suggest that ice V probably deforms largely by dislocation creep, while ice VI deforms by a more complicated process involving substantial grain size reduction through recrystallization. C1 US GEOL SURVEY, MS 977, MENLO PK, CA 94025 USA. RP Durham, WB (reprint author), LAWRENCE LIVERMORE NATL LAB, L-201, BOX 808, LIVERMORE, CA 94550 USA. NR 25 TC 14 Z9 14 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1996 VL 101 IS B2 BP 2989 EP 3001 DI 10.1029/95JB03542 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV380 UT WOS:A1996TV38000016 ER PT J AU Johnson, PA Rasolofosaon, PNJ AF Johnson, PA Rasolofosaon, PNJ TI Nonlinear elasticity and stress-induced anisotropy in rock SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID EARTHS CRUST; RATIO AB The elastic nonlinear behavior of rocks as evidenced by deviations from Hooke's law in stress-strain measurements, and attributable to the presence of mechanical defects (compliant features such as cracks, microfractures, grain joints), is a well-established observation. The purpose of this paper is to make the connection between the elastic nonlinearity and stress-induced effects on waves, in this case uniaxial-stress-induced transverse isotropy. The linear and nonlinear elastic coefficients constitute the most condensed manner in which to characterize the elastic behavior of the rock. We present both the second- and the third-order nonlinear elastic constants obtained from experimental data on rock samples assumed homogeneous and isotropic when unstressed. As is normally the case, the third-order (nonlinear) constants are found to be much larger than the second-order (linear) elastic constants. Contrary to results from intact homogeneous solids (materials without mechanical defects), rocks exhibit weak to strong nonlinearity and always in the same manner (i.e., an increase of the moduli with pressure). As a consequence the stress-induced P wave anisotropy and S wave birefringence can be large. The stress-induced P wave anisotropy appears to be much larger than the S wave birefringence. The fast direction is parallel to the stress direction, and the anisotropy goes as sin(2) theta, theta being the angle between the propagation direction and the stress direction. Experiments on rocks indicate that at low applied stresses, the proportionality of the stress and the induced S birefringence and P anisotropy predicted by theory is well corroborated. C1 INST FRANCAIS PETR, F-92506 RUEIL MALMAISON, FRANCE. UNIV PARIS 06, DEPT RECH PHYS, PARIS, FRANCE. RP LOS ALAMOS NATL LAB, DIV EARTH & ENVIRONM SCI, GEOL ENGN GRP, MAIL STOP D443, LOS ALAMOS, NM 87545 USA. NR 45 TC 74 Z9 77 U1 1 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD FEB 10 PY 1996 VL 101 IS B2 BP 3113 EP 3124 DI 10.1029/95JB02880 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV380 UT WOS:A1996TV38000025 ER PT J AU Chu, CS Ho, PM Zumino, B AF Chu, CS Ho, PM Zumino, B TI The braided quantum two-sphere SO MODERN PHYSICS LETTERS A LA English DT Article AB In a recent paper the quantum two-sphere S-q(2) was described as a quantum complex manifold. Here we consider several copies of S(q)(2)and derive their braiding commutation relations. The braiding is extended to the differential and to the integral calculus on the spheres. A quantum analog of the classical anharmonic ratio of four points on the sphere is given, which is invariant under the co-action of SUq(2). C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. RP Chu, CS (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Chu, chong-sun/J-8842-2012 NR 8 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-7323 J9 MOD PHYS LETT A JI Mod. Phys. Lett. A PD FEB 10 PY 1996 VL 11 IS 4 BP 307 EP 316 DI 10.1142/S0217732396000357 PG 10 WC Physics, Nuclear; Physics, Particles & Fields; Physics, Mathematical SC Physics GA TY575 UT WOS:A1996TY57500006 ER PT J AU Abrikosov, AA AF Abrikosov, AA TI On the c-axis conductivity and superconductivity of YBa2Cu3Ox as function of x SO PHYSICA C LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; VALENCE-BOND STATE; NORMAL TRANSPORT; DIAGNOSTICS; GAP AB A theory is presented of the static c-axis conductivity and superconductivity of the YBCO state with varying oxygen concentration. The basis of the theory is the assumption that the hopping of electrons between the CuO2 planes is due to resonant tunneling through localized centers between the planes, acid the amplitudes for different centers with the same energy are coherent. The dependence of the normal conductivity on temperature and concentrations of the resonant centers is calculated. Comparison with recent systematic determinations of the temperature-dependent conductivity at different oxygen concentrations shows reasonable agreement. From the obtained dependence of the concentration of resonant centers on the oxygen concentration it can be concluded that these centers disappear simultaneously with holes in the valence band, and hence both originate from the same impurity states with energies below the top of the valence band, which disappear at a certain doping. The supercurrent in the superconducting state proves to be of the Josephson type. The critical value is defined as a function of temperature and concentration of resonant centers. Its magnitude is estimated to be J(c) similar to 10(5)-10(7) A/cm(2). RP Abrikosov, AA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 16 TC 25 Z9 25 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 10 PY 1996 VL 258 IS 1-2 BP 53 EP 60 DI 10.1016/0921-4534(95)00835-7 PG 8 WC Physics, Applied SC Physics GA TY947 UT WOS:A1996TY94700007 ER PT J AU vanderBeek, CJ Indenbom, MV DAnna, G Benoit, W AF vanderBeek, CJ Indenbom, MV DAnna, G Benoit, W TI Nonlinear AC susceptibility, surface and bulk shielding SO PHYSICA C LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; PERPENDICULAR MAGNETIC-FIELD; HARMONIC-GENERATION; II SUPERCONDUCTORS; FLUX-CREEP; CRYSTALS; STATE; PENETRATION; RELAXATION; BARRIERS AB We calculate the nonlinear AC response of a thin superconducting strip in perpendicular field, shielded by an edge current due to the geometrical barrier. A comparison with the results for infinite samples in parallel field, screened by a surface barrier, and with those for screening by a bulk current in the critical state, shows that the AC response due to a barrier has general features that are independent of geometry, and that are significantly different from those for screening by a bulk current in the critical state. By consequence, the nonlinear (global) AC susceptibility can be used to determine the origin of magnetic irreversibility. A comparison with experiments on a Bi2Sr2CaCu2O8+delta crystal shows that in this material, the low-frequency AC screening at high temperature is mainly due to the screening by an edge current, and that this is the unique source of the nonlinear magnetic response at temperatures above 40 K. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,ARGONNE,IL 60439. RUSSIAN ACAD SCI,INST SOLID STATE PHYS,CHERNOGOLOVKA 142432,RUSSIA. RP vanderBeek, CJ (reprint author), ECOLE POLYTECH FED LAUSANNE,DEPT PHYS,IGA,CH-1015 LAUSANNE,SWITZERLAND. NR 52 TC 44 Z9 44 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 10 PY 1996 VL 258 IS 1-2 BP 105 EP 120 DI 10.1016/0921-4534(95)00774-1 PG 16 WC Physics, Applied SC Physics GA TY947 UT WOS:A1996TY94700014 ER PT J AU Ren, ZF Wang, CA Wang, JH Miller, DJ Christen, DK Hettinger, JD Gray, KE AF Ren, ZF Wang, CA Wang, JH Miller, DJ Christen, DK Hettinger, JD Gray, KE TI Composition and phase development of epitaxial superconducting Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9-delta thin films by laser ablation and post annealing SO PHYSICA C LA English DT Article ID TAPE; TL AB For the formation of epitaxial superconducting Tl0.78Bi0.22Sr1.6Ba0.4Ca2Cu3O9-delta ((Tl,Bi)-1223) thin films, the dependence of phase development on the chemical state of the source materials, deposition distance from source to substrate, and O-2 pressure during deposition by laser ablation and post annealing was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). It was found necessary to have thallium in the precursor film and that a reacted source target is better than the unreacted source for obtaining (Tl,Bi)-1223 phase-pure films. Better(Tl,Bi)-1223 films were obtained at a deposition distance of 44 mm from source to substrate than at a distance of 61 mm over a range of O-2 pressure from 5.7 to 31.3 mTorr The best films prepared under the optimal conditions exhibited transport J(c) close to 3 X 10(6) A/cm(2) at 77 K and zero field. C1 SUNY BUFFALO,NEW YORK STATE INST SUPERCONDUCT,BUFFALO,NY 14260. SUNY BUFFALO,DEPT CHEM,SUPERCOND MAT LAB,BUFFALO,NY 14260. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RI Ren, Zhifeng/B-4275-2014 NR 16 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 10 PY 1996 VL 258 IS 1-2 BP 129 EP 136 PG 8 WC Physics, Applied SC Physics GA TY947 UT WOS:A1996TY94700016 ER PT J AU Edler, KJ Reynolds, PA Trouw, F White, JW AF Edler, KJ Reynolds, PA Trouw, F White, JW TI Methane dynamics in the 36 angstrom mesopores of MCM-41 studied by neutron scattering SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MODEL AB The capillary melting of methane adsorbed into the uniform parallel mesopores of the new silicate MCM-41 has been studied by neutron inelastic scattering and neutron quasielastic scattering at an energy resolution of about 80 microelectron volts. Differences from bulk methane in both the rotational melting and the solid to liquid transition have been identified. Rotational melting occurs at about 35 K, nearly ten degrees above the onset for the bulk; translational melting starts at around 60 K, nearly 30 degrees below the melting point of bulk methane. C1 ARGONNE NATL LAB,INTENSE PULSED NEUTRON SOURCE,ARGONNE,IL 60439. RP Edler, KJ (reprint author), AUSTRALIAN NATL UNIV,RES SCH CHEM,GPO BOX 4,CANBERRA,ACT 0200,AUSTRALIA. RI Edler, Karen/A-7324-2011 OI Edler, Karen/0000-0001-5822-0127 NR 14 TC 8 Z9 8 U1 3 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 FEB 9 PY 1996 VL 249 IS 5-6 BP 438 EP 443 DI 10.1016/0009-2614(95)01440-3 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TW650 UT WOS:A1996TW65000022 ER PT J AU Watts, JD Franz, JA Bartlett, RJ AF Watts, JD Franz, JA Bartlett, RJ TI Radical hydrogen transfer reactions: Benchmark calculations on the C2H4 center dot center dot center dot H center dot center dot center dot C2H4 transition state SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SHELL HARTREE-FOCK; COUPLED-CLUSTER SINGLES; MOLECULAR-ORBITAL METHODS; BODY PERTURBATION-THEORY; GAUSSIAN-TYPE BASIS; MANY-BODY; ENERGY GRADIENTS; BASIS SETS; ORGANIC-MOLECULES; ATOMS AB High level ab initio calculations using coupled-cluster (CC) methods have been applied to calculate the barrier height of the prototypical hydrocarbon radical hydrogen transfer reaction between C2H4 and C2H5. The barrier at 298 K is estimated to be 27.7-30.7 kcal mol(-1). Second-order perturbation theory based on a restricted open-shell Hartree-Fock reference, unlike spin contaminated UHF-MBPT(2), provides reasonable agreement with the CC calculations, and may be of use in studies of the RHT reaction of larger systems. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. RP Watts, JD (reprint author), UNIV FLORIDA, QUANTUM THEORY PROJECT, 362 WILLIAMSON HALL, POB 118435, GAINESVILLE, FL 32611 USA. RI Bartlett, Rodney/F-6781-2011 OI Bartlett, Rodney/0000-0003-3865-9639 NR 32 TC 10 Z9 10 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 FEB 9 PY 1996 VL 249 IS 5-6 BP 496 EP 500 DI 10.1016/0009-2614(95)01420-9 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TW650 UT WOS:A1996TW65000030 ER PT J AU North, SW Zheng, XS Fei, R Hall, GE AF North, SW Zheng, XS Fei, R Hall, GE TI Line shape analysis of Doppler broadened frequency-modulated line spectra SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SCHULER-BAND ABSORPTION; LASER FM SPECTROSCOPY; VECTOR CORRELATIONS; DIODE-LASER; PHOTODISSOCIATION AB We present a method for recovering Doppler broadened absorption line shapes from frequency modulated (FM) line spectra. The method of analysis is calibrated and demonstrated with thermalized CN radicals produced by photodissociation of cyanogen (NCCN), probed on the A-X system near 800 nm with a frequency modulated Ti: sapphire ring laser. Nonthermal, Doppler broadened lines from translationally nascent photofragments can also be recovered by direct transformations of experimental FM line profiles acquired with a time resolution exceeding 100 ns. The superior signal-to-noise afforded by FM spectroscopy, relative to other direct absorption methods, should encourage the application of transient FM spectroscopy to problems in photoinitiated reaction dynamics. (C) 1996 American Institute of Physics. RP North, SW (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI North, Simon/G-5054-2012; Hall, Gregory/D-4883-2013 OI North, Simon/0000-0002-0795-796X; Hall, Gregory/0000-0002-8534-9783 NR 37 TC 47 Z9 50 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1996 VL 104 IS 6 BP 2129 EP 2135 DI 10.1063/1.470969 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TU447 UT WOS:A1996TU44700001 ER PT J AU Niu, BH White, MG AF Niu, BH White, MG TI Geometry changes in molecular photoionization: The NH3+ ((X)over-bar-(2) A(2)'')<-NH3(X(1)A(1)) transition SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ENERGY PHOTOELECTRON-SPECTRUM; NEAR-THRESHOLD PHOTOIONIZATION; ELECTRONIC GROUND-STATE; NITRIC-OXIDE; AMMONIA; SPECTROSCOPY; IONIZATION; RESOLUTION; H2O AB Single-photon threshold photoionization has been used to explore the ionization dynamics of the NH3+ ((X) over tilde (2)A(2)'')<--NH3 (X (1)A(1)) transition which involves a pyramidal-to-planar geometry change. Rotationally resolved threshold photoelectron spectra are presented for four vibrational levels of the (X) over tilde (2)A(2)'' cation state of NH3+ corresponding to excitation of even and odd quanta of the inversion mode, nu(2)(+). The rotational state distributions exhibit strong symmetry effects imposed by the nuclear spin statistics and vibronic parity of the neutral and cation out-of-plane bend levels. The observed rotational structure is consistent with dominant Delta K=0 transitions and parity assignments for specific transitions show that both l=even and l=odd photoelectron final states are excited. These observations indicate that the photoelectron experiences a non-planar (pyramidal) cation potential. These results are discussed in light of previous rotationally resolved measurements on NH3 using multiphoton ionization and other systems which undergo bend excitation following ionization. (C) 1996 American Institute of Physics. RP Niu, BH (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 32 TC 14 Z9 14 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1996 VL 104 IS 6 BP 2136 EP 2145 DI 10.1063/1.471647 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TU447 UT WOS:A1996TU44700002 ER PT J AU Goeringer, DE McLuckey, SA AF Goeringer, DE McLuckey, SA TI Evolution of ion internal energy during collisional excitation in the Paul ion trap: A stochastic approach SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NORMAL-BUTYLBENZENE IONS; INFRARED-LASER PHOTODISSOCIATION; MASS-SPECTROMETRY; LOW-PRESSURE; DISSOCIATION; KINETICS AB A first-order model is developed for collisional activation as effected via resonance excitation and helium buffer gas in the Paul ion trap. For an ion population at steady-state under specified experimental conditions, the kinetic theory of ion transport in gases is first used to calculate an effective temperature shown to be identical to the internal temperature for molecular ions in an atomic gas. The evolution of the ion internal energy is then followed by a random walk simulation designed to be representative of the actual collisional energy transfer process, except ion losses due to dissociation and reactive processes during collisional activation are excluded. During the simulation, inelastic ion-neutral collisions increase the average ion internal energy via small energy changes (both positive and negative) until a steady-state condition is reached in which excitation and deexcitation processes are balanced. Histogramming the simulated data reveals a Boltzmann-type internal energy distribution whose average internal energy is the same as that calculated for a true Boltzmann distribution at the same internal temperature. (C) 1996 American Institute of Physics. RP Goeringer, DE (reprint author), OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831, USA. RI McLuckey, Scott/B-2203-2009 OI McLuckey, Scott/0000-0002-1648-5570 NR 40 TC 68 Z9 68 U1 0 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 8 PY 1996 VL 104 IS 6 BP 2214 EP 2221 DI 10.1063/1.471812 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA TU447 UT WOS:A1996TU44700010 ER PT J AU Hessler, JP AF Hessler, JP TI Global fits of methyl-methyl recombinational data to Prezhdo's new interpolation formula SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article AB Prezhdo has suggested (J. Phys. Chem. 1995, 99, 8633) a new interpolation formula for the pressure-dependent behavior of dissociative and recombinational reactions. This formula, k(P-r) = k(infinity)[P-p/{1 + P-r + (P-r/B)(A)}], introduces two phenomenological parameters, A and B. Fits to isothermal methyl-methyl recombinational data are used to determine their temperature dependence. Global fits to an extensive set of data give high-pressure rates coefficients which are compared to values derived by other formulations. RP Hessler, JP (reprint author), ARGONNE NATL LAB,DIV CHEM,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 10 TC 12 Z9 12 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-3654 J9 J PHYS CHEM-US JI J. Phys. Chem. PD FEB 8 PY 1996 VL 100 IS 6 BP 2141 EP 2144 DI 10.1021/jp9524587 PG 4 WC Chemistry, Physical SC Chemistry GA TU975 UT WOS:A1996TU97500025 ER PT J AU Olariu, S Rao, NSV AF Olariu, S Rao, NSV TI Simple algorithms for some classification problems SO PATTERN RECOGNITION LETTERS LA English DT Article DE classification; pattern recognition; partitions; equivalence relations; refinement AB Consider two classifiers C-1 and C-2 each partitioning a collection A of n objects into classes based on respective sets of features. In a number in pattern recognition and knowledge engineering applications, the following problems arise: given the two partitions generated by C-1 and C-2, compute new partitions by considering (i) the features common to both classifiers, and (ii) the features of either of the classifiers. We show that both problems can be solved in Theta(n log n) time using very simple algorithms. C1 OAK RIDGE NATL LAB,CTR ENGN SYST ADV RES,OAK RIDGE,TN 37831. RP Olariu, S (reprint author), OLD DOMINION UNIV,DEPT COMP SCI,NORFOLK,VA 23529, USA. OI Rao, Nageswara/0000-0002-3408-5941 NR 7 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8655 J9 PATTERN RECOGN LETT JI Pattern Recognit. Lett. PD FEB 8 PY 1996 VL 17 IS 2 BP 163 EP 167 DI 10.1016/0167-8655(95)00095-X PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA TV874 UT WOS:A1996TV87400008 ER PT J AU George, GN Hilton, J Rajagopalan, KV AF George, GN Hilton, J Rajagopalan, KV TI X-ray absorption spectroscopy of dimethyl sulfoxide reductase from Rhodobacter sphaeroides SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRON-PARAMAGNETIC-RESONANCE; BOND-VALENCE PARAMETERS; XANTHINE-OXIDASE; MOLYBDENUM COFACTOR; NITRATE REDUCTASE; ESCHERICHIA-COLI; SULFITE OXIDASE; DMSO REDUCTASE; DENITRIFICANS; COMPLEXES AB X-ray absorption spectroscopy at the molybdenum K-edge has been used to probe the molybdenum coordination of Rhodobacter sphaeroides dimethyl sulfoxide reductase. The molybdenum site of the oxidized protein possesses a novel Mo(VI) mono-ore site (Mo=O at 1.68 Angstrom) with additional coordination by approximately four thiolate ligands at 2.44 Angstrom and probably one oxygen or nitrogen at 1.92 Angstrom. The reduced Mo(IV) form of the enzyme is a des-oxomolybdenum with 3-4 thiolates at 2.33 Angstrom and two different Mo-O/N ligands at 2.16 Angstrom and 1.92 Angstrom. Similarly, the stable Mo(V) glycerol-inhibited species is found to be a des-oxomolybdenum with approximately four thiolate ligands at 2.40 Angstrom and (probably) two similarly coordinated oxygen or nitrogen ligands at 1.96 Angstrom. C1 DUKE UNIV, SCH MED, DEPT BIOCHEM, DURHAM, NC 27710 USA. RP George, GN (reprint author), STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD SYNCHROTRON RADIAT LAB, POB 4349, STANFORD, CA 94309 USA. RI George, Graham/E-3290-2013 NR 44 TC 108 Z9 108 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 FEB 7 PY 1996 VL 118 IS 5 BP 1113 EP 1117 DI 10.1021/ja953317l PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA TU348 UT WOS:A1996TU34800024 ER PT J AU Yang, HC Dermody, DL Xu, CJ Ricco, AJ Crooks, RM AF Yang, HC Dermody, DL Xu, CJ Ricco, AJ Crooks, RM TI Molecular interactions between organized, surface-confined monolayers and vapor-phase probe molecules .8. Reactions between acid-terminated self-assembled monolayers and vapor-phase bases SO LANGMUIR LA English DT Article ID INFRARED-SPECTROSCOPY; GOLD; ADSORPTION; FILMS AB We present the results of a study of the interactions between three different acid-terminated self-assembled monolayer (SAM) surfaces and three basic vapor-phase probe molecules. The SAMs are composed of 4-mercaptobenzoic acid (MBA), 3-mercaptopropionic acid (MPA), and 11-mercaptoundecanoic acid (MUA), and the vapor-phase probes are, in order of increasing solution-phase acidity, decylamine, pyridine, and pyrazine. Our results are based on data from surface infrared spectroscopy and thickness-shear mode mass sensors. We find that all three SAMs irreversibly bind approximately one monolayer of decylamine, although there are slight differences that correlate with the structural nuances of the SAMs. The MPA and MBA SAMs bind decylamine through an electrostatic interaction brought about by transfer of a proton from the acid to the base. Because the MUA SAM is more impenetrable than the others, complete proton transfer is hindered, and binding of decylamine arises through a combination of proton transfer and strong hydrogen bonding. In the presence of its vapor, pyridine adsorbs to MBA surfaces at near-monolayer coverage, but upon N-2 purging about two-thirds of it desorbs. Only one-half monolayer of pyrazine, which is less basic than pyridine, adsorbs to the MBA SAM, and upon N-2 purging, about two-thirds of it desorbs. The aliphatic acid SAMs follow a similar trend. The results of this study indicate that the extent of base binding correlates most strongly with the structural nuances of the acidic SAMs and the relative basicity of the vapor-phase bases. These results are relevant to SAM-based chemical sensors. C1 TEXAS A&M UNIV,DEPT CHEM,COLLEGE STN,TX 77843. SANDIA NATL LABS,MICROSENSOR RES & DEV DEPT,ALBUQUERQUE,NM 87185. RI Ricco, Antonio/A-5273-2010; OI Ricco, Antonio/0000-0002-2355-4984 NR 48 TC 97 Z9 97 U1 0 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 7 PY 1996 VL 12 IS 3 BP 726 EP 735 DI 10.1021/la9505226 PG 10 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TV466 UT WOS:A1996TV46600016 ER PT J AU Palmer, BJ Liu, J AF Palmer, BJ Liu, J TI Simulations of micelle self-assembly in surfactant solutions SO LANGMUIR LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; WATER OIL INTERFACE; LIQUID-CRYSTAL; COMPUTER-SIMULATIONS; SODIUM OCTANOATE; MODEL; MICROEMULSIONS; TEMPERATURE AB A simple model of surfactants in aqueous solution is described and molecular dynamics simulations are presented. This model qualitatively reproduces the energy ordering of interactions for surfactants in solution, instead of using the symmetric solvent-solvent and hydrocarbon-hydrocarbon interactions used previously in similar models. The effects of surfactant chain length and concentration are investigated. The results show that the tendency toward micelle formation in the model increases as the chain length is increased and that the type of micelle formed varies with surfactant concentration. Transitions from loose aggregates to spherical micelles to cylindrical micelles are seen as surfactant chain length is increased. A transition from cylindrical micelles to spherical micelles is also seen as surfactant concentration is lowered. RP Palmer, BJ (reprint author), PACIFIC NW NATL LAB,ENERGY & ENVIRONM SCI DIV,RICHLAND,WA 99352, USA. NR 31 TC 79 Z9 79 U1 1 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 7 PY 1996 VL 12 IS 3 BP 746 EP 753 DI 10.1021/la950979f PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TV466 UT WOS:A1996TV46600019 ER PT J AU Clark, DL Grumbine, SK Scott, BL Watkin, JG AF Clark, DL Grumbine, SK Scott, BL Watkin, JG TI Sterically demanding aryloxides as supporting ligands in organoactinide chemistry. Synthesis, structural characterization, and reactivity of Th(O-2,6-t-Bu(2)C(6)H(3))(2)(CH(2)SiMe(3))(2) and formation of the trimeric thorium hydride Th3H6(O-2,6-t-Bu(2)C(6)H(3))(6) SO ORGANOMETALLICS LA English DT Article ID RAY CRYSTAL-STRUCTURE; ARYL OXIDE COMPOUNDS; F-BLOCK METALS; MOLECULAR-STRUCTURE; SPECTROSCOPIC PROPERTIES; CATALYTIC-HYDROGENATION; SURFACE-CHEMISTRY; CYCLOMETALATION CHEMISTRY; URANIUM TETRACHLORIDE; ALKOXIDE CHEMISTRY AB Reaction of ThBr4(THF)(4) with 2 equiv of KOAr (Ar = 2,6-t-Bu(2)C(6)H(3)) produces the bis(aryloxide) complex ThBr2(OAr)(2)(THF)(2) (1) in 67% yield. Alkylation of 1 with 2 equiv of Me(3)SiCH(2)MgCl allows the isolation of Th(OAr)2(CH(2)SiMe(3))(2) (2) in 61% yield. Thermolysis of 2 (benzene, 60 degrees C, 36 h) in the presence of NEt(3) results in the formation of the cyclometalated ligand redistribution product Th(OC6H3-t-BuCMe(2)CH(2))(OAr)(2) (3). Reaction of 2 with 1 equiv of 2,6-dimethylphenyl isocyanate leads to insertion into the Th-C bond to yield (ArO)(2)Th[OC(=NR)CH(2)SiMe(3)](CH(2)SiMe(3)) (4; R = 2,6-Me(2)C(6)H(3)) Aminolysis of 2 with 2 equiv of 2,6-diisopropylaniline allows the isolation of the bls(amido) species Th(OAr)(2)(NH2,6-i-Pr2C6H3)(2) (5) in 92% yield. 2 reacts with dihydrogen (1.5 atm) over a period of 7 days to form the trimeric dihydride complex Th-3(mu(3)-H)(2)(mu(2)-H)(4)(OAr)(6) (6) In the presence of 1 equiv of [HNMe(2)Ph][B(C6F5)(4)], 2 catalyzes the hydrogenation of 1-hexene (N-t = 1 h(-1)), while 6 is found to be a single-component catalyst for the analogous process (N-t = 3 h(-1)). Complexes 1-6 have been characterized by H-1 NMR and IR spectroscopy, microanalysis, and, in the case of 2 and 6, by single-crystal X-ray diffraction studies. 2 comprises a pseudotetrahedral thorium metal center bearing two aryloxide and two alkyl ligands. The O-Th-O angle between the aryloxide ligands (119.2(4)degrees) is significantly larger than the C-Th-C angle (101.4(6)degrees). Th-O and Th-C distances average 2.137(11) and 2.462(18)% respectively, while Th-C-Si angles are 125.9(8) and 122.8(8)degrees. The alkyl groups of 2 also display a reduced C-H coupling constant (J(CH) = 98 Hz), suggestive of cl-agostic interaction between the methylene group and the Th metal center. 6 exhibits a triangular arrangement of three thorium metal centers, each bearing two terminal aryloxide ligands. Two sides of the trimetallic core (Th-Th distances 3.781(1) and 3.818(1) Angstrom) are bridged by single mu(2)-hydride ligands, while the third side is bridged by two mu(2)-hydride ligands (Th-Th distance 3.588(1) Angstrom). Each face of the trimer is capped by a mu(3)-hydride ligand to produce a structurally unique M(3)(mu(3)-X)(2)(mu(2)-X)(4)X(6) geometry. Th-(mu(2)-H) and Th-(mu(3)-H) distances lie in the ranges 2.0(1)-2.3(1) and 2.3(1)-2.6(1) Angstrom, respectively, while Th-O distances range from 2.126(7) to 2.164(7) Angstrom. RP Clark, DL (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,POB 1663,LOS ALAMOS,NM 87545, USA. RI Clark, David/A-9729-2011; Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 91 TC 32 Z9 32 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD FEB 6 PY 1996 VL 15 IS 3 BP 949 EP 957 DI 10.1021/om950654u PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA TU702 UT WOS:A1996TU70200011 ER PT J AU McKenna, JM Nolte, DD Walukiewicz, W Becla, P AF McKenna, JM Nolte, DD Walukiewicz, W Becla, P TI Persistent holographic absorption gratings in AlSb:Se SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTORS; LEVEL AB Photoquenching of DX-like defects in heavily doped AlSb:Se is used to write persistent volume absorption holograms. Read-out diffraction efficiencies of similar to 0.5% were observed in samples 280 mu m thick. The optical gratings are metastable, and semipermanent at liquid nitrogen temperatures, and are reversibly erased by heating the crystal above 140 K. The activation energy of regeneration of the stable DX state is obtained by measuring the decay times of the diffracted signal for temperatures between 100 and 116 K. We obtain a regeneration energy of 180 meV. Larger regeneration energies are important for eventual application of this material class to holographic optical memories. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. MIT,DEPT MAT SCI & ENGN,CAMBRIDGE,MA 02139. RP McKenna, JM (reprint author), PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907, USA. NR 12 TC 13 Z9 13 U1 1 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 5 PY 1996 VL 68 IS 6 BP 735 EP 737 DI 10.1063/1.116725 PG 3 WC Physics, Applied SC Physics GA TT663 UT WOS:A1996TT66300003 ER PT J AU Pharr, GM Callahan, DL McAdams, SD Tsui, TY Anders, S Anders, A Ager, JW Brown, IG Bhatia, CS Silva, SRP Robertson, J AF Pharr, GM Callahan, DL McAdams, SD Tsui, TY Anders, S Anders, A Ager, JW Brown, IG Bhatia, CS Silva, SRP Robertson, J TI Hardness, elastic modulus, and structure of very hard carbon films produced by cathodic-arc deposition with substrate pulse biasing SO APPLIED PHYSICS LETTERS LA English DT Article ID DIAMOND-LIKE CARBON; AMORPHOUS-CARBON AB The hardness, elastic modulus, and structure of several amorphous carbon films on silicon prepared by cathodic-are deposition with substrate pulse biasing have been examined using nanoindentation, energy loss spectroscopy (EELS), and cross-sectional transmission electron microscopy. EELS analysis shows that the highest sp(3) contents (85%) and densities (3.00 g/cm(3)) are achieved at incident ion energies of around 120 eV. The hardness and elastic modulus of the films with the highest sp(3) contents are at least 59 and 400 GPa, respectively. These values are conservative lower estimates due to substrate influences on the nanoindentation measurements. The films are predominantly amorphous with a similar to 20 nm surface layer which is structurally different and softer than the bulk. (C) 1996 American Institute of Physics. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. IBM CORP,SAN JOSE,CA 95193. UNIV CAMBRIDGE,DEPT ENGN,CAMBRIDGE CB2 1PZ,ENGLAND. RP Pharr, GM (reprint author), RICE UNIV,DEPT MAT SCI,HOUSTON,TX 77251, USA. RI Silva, S. Ravi/J-9210-2014; Anders, Andre/B-8580-2009; Raoux, Simone/G-3920-2016; OI Silva, S. Ravi/0000-0002-0356-1319; Anders, Andre/0000-0002-5313-6505; Ager, Joel/0000-0001-9334-9751 NR 23 TC 203 Z9 204 U1 2 U2 24 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 5 PY 1996 VL 68 IS 6 BP 779 EP 781 DI 10.1063/1.116530 PG 3 WC Physics, Applied SC Physics GA TT663 UT WOS:A1996TT66300018 ER PT J AU Werner, TR Sheikh, JA Misu, M Nazarewicz, W Rikovska, J Heeger, K Umar, AS Strayer, MR AF Werner, TR Sheikh, JA Misu, M Nazarewicz, W Rikovska, J Heeger, K Umar, AS Strayer, MR TI Ground-state properties of exotic Si, S, Ar and Ca isotopes SO NUCLEAR PHYSICS A LA English DT Article ID HARTREE-FOCK CALCULATIONS; NUCLEAR-CHARGE RADII; SYSTEMATICS; SHELL; COEXISTENCE; TRANSITION; REGION; S-32 AB Masses, deformations, radii, two-neutron separation energies and single-particle properties of Si, S, Ar and Ca isotopes are investigated in the framework of the self-consistent mean-field theory. In particular, the role of the N = 28 gap in the neutron-rich isotopes, and differences between proton and neutron deformations are discussed. C1 UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. WARSAW UNIV,INST THEORET PHYS,PL-00681 WARSAW,POLAND. JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. TATA INST FUNDAMENTAL RES,BOMBAY 400005,MAHARASHTRA,INDIA. UNIV MARYLAND,DEPT CHEM,COLLEGE PK,MD 20742. VANDERBILT UNIV,DEPT PHYS,NASHVILLE,TN 37235. UNIV OXFORD,DEPT PHYS,OXFORD OX1 3PU,ENGLAND. RP Werner, TR (reprint author), OAK RIDGE NATL LAB,DIV PHYS,POB 2008,OAK RIDGE,TN 37831, USA. RI Heeger, Karsten/A-4413-2011; Umar, Ahmet/J-4125-2013 OI Umar, Ahmet/0000-0002-9267-5253 NR 45 TC 128 Z9 128 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD FEB 5 PY 1996 VL 597 IS 3 BP 327 EP 340 DI 10.1016/0375-9474(95)00476-9 PG 14 WC Physics, Nuclear SC Physics GA TX739 UT WOS:A1996TX73900001 ER PT J AU Farhan, AR Canto, LF Rasmussen, J AF Farhan, AR Canto, LF Rasmussen, J TI Form factors for two-nucleon transfer in the diabolical region of rotating nuclei SO NUCLEAR PHYSICS A LA English DT Article ID PAIR-TRANSFER; 2-NEUTRON TRANSFER; PHASE AB The theoretical investigation of rotational bands in strongly deformed nuclei by Coulomb excitation and the subsequent transfer of nucleon pairs requires the knowledge of two-nucleon transfer amplitudes between rotating eigenstates of the A and the A +/- 2 systems. In a semiclassical approximation these amplitudes are obtained by integrating over transfer form factors depending on the orientation angle of the deformed target nucleus. We use the cranking approximation based on a rotating mean field in order to calculate these transfer form factors. Their behavior is studied as a function of angular momentum, deformation and pairing correlations. In the region of diabolical points these form factors show considerable oscillations and phase changes reflecting the microscopic single-particle structure involved in these matrix elements. Tn this way we are able to understand the underlying microscopic structure causing the diabolical behavior of pair transfer in this region. C1 UNIV FED RIO DE JANEIRO,INST FIS,BR-21944 RIO JANEIRO,BRAZIL. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. TECH UNIV MUNCHEN WEIHENSTEPHAN,DEPT PHYS,D-85747 GARCHING,GERMANY. RP Farhan, AR (reprint author), KUWAIT UNIV,DEPT PHYS,KUWAIT,KUWAIT. RI Canto, Luiz /I-3733-2012; Ring, Peter/O-1638-2015 NR 30 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD FEB 5 PY 1996 VL 597 IS 3 BP 387 EP 407 DI 10.1016/0375-9474(95)00456-4 PG 21 WC Physics, Nuclear SC Physics GA TX739 UT WOS:A1996TX73900005 ER PT J AU Granderath, A Mantica, PF Bengtsson, R Wyss, R vonBrentano, P Gelberg, A Seiffert, F AF Granderath, A Mantica, PF Bengtsson, R Wyss, R vonBrentano, P Gelberg, A Seiffert, F TI Shapes and rotational structures of neutron h(11/2) configurations in the Xe-Ba-Ce region SO NUCLEAR PHYSICS A LA English DT Article ID HIGH-SPIN STATES; 1ST IDENTIFICATION; COMPETING PROTON; TRIAXIAL SHAPES; EXCITED-STATES; MASS REGION; BANDS; NUCLEI; SPECTROSCOPY; ALIGNMENTS AB Rotational bands built on neutron h(11/2) states are investigated within the Strutinsky mean-field concept. Calculated deformation trajectories of one-, three- and five-quasiparticle configurations are presented. The experimentally observed signature splitting and crossing frequencies in Xe-Ba-Ce nuclei are compared to theoretical predictions. The systematics of the observed band structures can only be accounted for by allowing a smooth transition from prolate to oblate structure via triaxial shapes as the number of neutrons increases. C1 JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. UNIV COLOGNE,INST KERNPHYS,W-5000 COLOGNE,GERMANY. LUND INST TECHNOL,S-22100 LUND,SWEDEN. RP Granderath, A (reprint author), OAK RIDGE INST SCI & EDUC,UNISOR,OAK RIDGE,TN 37831, USA. NR 46 TC 48 Z9 48 U1 0 U2 2 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 FEB 5 PY 1996 VL 597 IS 3 BP 427 EP 471 DI 10.1016/0375-9474(95)00484-X PG 45 WC Physics, Nuclear SC Physics GA TX739 UT WOS:A1996TX73900007 ER PT J AU Wells, JD Kane, GL AF Wells, JD Kane, GL TI Implications for supersymmetry of the reported deviations from the standard model for Gamma(Z->b(b)over-bar) and alpha(s)(m(z)(2)) SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGGS-BOSON-MASS; RADIATIVE-CORRECTIONS; SUM-RULES AB If the reported excess (over the standard model prediction) for Z --> from LEP persists, and is explained by supersymmetric particles in loops, then we show that (1) a superpartner (chargino and/or stop) will be detected at LEP2, and probably at intermediate energy upgrades, (2) the basic parameter tan beta is at its lower perturbative limit, (3) BR(t --> (t) over tilde(1) + <(chi)over tilde>(0)) is at or above 0.4, (4) the upper limit on m(h) is considerably reduced, and (5) several important consequences arise for the form of a unified supersymmetric theory. Our analysis is done in terms of a general weak scale Lagrangian and does not depend on assumptions about SUSY breaking. C1 UNIV MICHIGAN,RANDALL LAB PHYS,ANN ARBOR,MI 48109. RP Wells, JD (reprint author), STANFORD LINEAR ACCELERATOR CTR,MS 81,POB 4349,STANFORD,CA 94309, USA. NR 35 TC 41 Z9 41 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 FEB 5 PY 1996 VL 76 IS 6 BP 869 EP 872 DI 10.1103/PhysRevLett.76.869 PG 4 WC Physics, Multidisciplinary SC Physics GA TT491 UT WOS:A1996TT49100004 ER PT J AU Cheung, K Keung, WY Yuan, TC AF Cheung, K Keung, WY Yuan, TC TI Color-octet quarkonium production at the Z pole SO PHYSICAL REVIEW LETTERS LA English DT Article ID = 1.8 TEV; (P)OVER-BAR-P COLLISIONS; HEAVY QUARKONIUM; J/PSI-PRODUCTION; DECAY; FRAGMENTATION; MOMENTUM AB The direct production rate of J/psi, via the color-octet mechanism is calculated at the Z resonance. The color-octet production process Z --> is shown to have a substantial branching ratio as well as a distinctive energy spectrum, which can be used as a powerful tool to distinguish from the color-singlet direct production of the J/psi. C1 UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60607. FERMILAB NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CALIF DAVIS,DAVIS INST HIGH ENERGY PHYS,DAVIS,CA 95616. RP Cheung, K (reprint author), UNIV TEXAS,CTR PARTICLE PHYS,AUSTIN,TX 78712, USA. RI Cheung, Kingman/A-8380-2008 OI Cheung, Kingman/0000-0003-2176-4053 NR 32 TC 72 Z9 73 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 FEB 5 PY 1996 VL 76 IS 6 BP 877 EP 880 DI 10.1103/PhysRevLett.76.877 PG 4 WC Physics, Multidisciplinary SC Physics GA TT491 UT WOS:A1996TT49100006 ER PT J AU Zholents, AA Zolotorev, MS AF Zholents, AA Zolotorev, MS TI Femtosecond x-ray pulses of synchrotron radiation SO PHYSICAL REVIEW LETTERS LA English DT Article ID AMPLIFICATION; TI-AL2O3 AB A method capable of producing femtosecond pulses of synchrotron radiation is proposed. It is based on the interaction of femtosecond light pulses with electrons in a storage ring. The application of the method to the generation of ultrashort x-ray pulses at the Advanced Light Source of Lawrence Berkeley National Laboratory has been considered. The same method can also be used for extraction of electrons from a storage ring in ultrashort series of microbunches spaced by the periodicity of light wavelength. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP Zholents, AA (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DIV ACCELERATOR & FUS RES,CTR BEAM PHYS,BERKELEY,CA 94720, USA. NR 9 TC 148 Z9 148 U1 5 U2 18 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 FEB 5 PY 1996 VL 76 IS 6 BP 912 EP 915 DI 10.1103/PhysRevLett.76.912 PG 4 WC Physics, Multidisciplinary SC Physics GA TT491 UT WOS:A1996TT49100015 ER PT J AU Chico, L Crespi, VH Benedict, LX Louie, SG Cohen, ML AF Chico, L Crespi, VH Benedict, LX Louie, SG Cohen, ML TI Pure carbon nanoscale devices: Nanotube heterojunctions SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRONIC-STRUCTURE AB Introduction of pentagon-heptagon pair defects into the hexagonal network of a single carbon nanotube can change the helicity of the tube and alter its electronic structure. Using a tight-binding method to calculate the electronic structure of such systems we show that they behave as nanoscale metal/semiconductor or semiconductor/semiconductor junctions. These junctions could be the building blocks of nanoscale electronic devices made entirely of carbon. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV SCI MAT,BERKELEY,CA 94720. RI Chico, Leonor/H-6395-2015; OI Chico, Leonor/0000-0002-7131-1266; Crespi, Vincent/0000-0003-3846-3193 NR 11 TC 709 Z9 731 U1 1 U2 56 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 FEB 5 PY 1996 VL 76 IS 6 BP 971 EP 974 DI 10.1103/PhysRevLett.76.971 PG 4 WC Physics, Multidisciplinary SC Physics GA TT491 UT WOS:A1996TT49100030 ER PT J AU Moss, WC Clarke, DB White, JW Young, DA AF Moss, WC Clarke, DB White, JW Young, DA TI Sonoluminescence and the prospects for table-top micro-thermonuclear fusion SO PHYSICS LETTERS A LA English DT Article DE sonoluminescence; hydrodynamic simulations; thermonuclear fusion ID SYNCHRONOUS PICOSECOND SONOLUMINESCENCE; BUBBLE AB Hydrodynamic simulations of a collapsing bubble show that pure D-2 cannot exhibit picosecond sonoluminescence, because of its large sound speed. The addition of D2O vapor lowers the sound speed and produces calculated results consistent with experiments. A pressure spike added to the periodic driving amplitude creates temperatures that may be sufficient to generate a very small number of thermonuclear D-D fusion reactions in the bubble. RP Moss, WC (reprint author), LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 18 TC 60 Z9 63 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD FEB 5 PY 1996 VL 211 IS 2 BP 69 EP 74 DI 10.1016/0375-9601(95)00934-5 PG 6 WC Physics, Multidisciplinary SC Physics GA TV386 UT WOS:A1996TV38600001 ER PT J AU Plummer, MV Congdon, JD AF Plummer, MV Congdon, JD TI Rates of metabolism and water flux in free-ranging racers, Coluber constrictor SO COPEIA LA English DT Article ID LIZARDS; EXPENDITURE; ENERGETICS; REPTILES; SIRTALIS; ECOLOGY; MODE AB A combination of temperature-sensitive radiotelemetry and doubly labeled water was used to determine daily activity periods, thermal profiles, water flux rates, and field metabolic rates (FMR) of free-ranging racers (Coluber constrictor) in a temperate mesic habitat during summer. Results were compared to published values on the closely related, ecologically similar coachwhip (Masticophis flagellum), Racers were active from about 0900-1800 h. Most snakes were in positive water balance, Rates of water influx (9.49 ml/d) and efflux (9.13 ml/d) were related to rates of body mass change (mean = 0.35% d) and were about four times greater than those of Masticophis inhabiting a more xeric habitat, Mean activity temperature (32C), FMR (0.157 mi CO2/g/h), mass-specific daily metabolic energy expenditure (94.5 kJ/kg/d), calculated values of resting metabolism (20.3 kJ/kg/d), and activity metabolism (74.2 kJ/kg/d) in Coluber were all similar to those of Masticophis. We did not detect any relationship between FMR and either distance moved per day, frequency of activity, or body temperature, Water flux rates were greater in females than in males, but we observed no differences between sexes in body temperature or FMR. Compared to intermolt racers, molting racers had higher body temperatures and FMRs (2%, 15%) and lower water fluxes (17%, 25%), but none of these differences was significant. Compared to early in the activity season, racers in late season had lower body temperatures, were less active, and moved less. Water flux and FMR also decreased (13%, 21%), but the differences were not significant. C1 SAVANNAH RIVER ECOL LAB,AIKEN,SC 29802. NR 43 TC 10 Z9 10 U1 0 U2 9 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS BUSINESS OFFICE PI CARBONDALE PA SOUTHERN ILLINOIS UNIV, DEPT ZOOLOGY, CARBONDALE, IL 62901-6501 SN 0045-8511 J9 COPEIA JI Copeia PD FEB 2 PY 1996 IS 1 BP 8 EP 14 DI 10.2307/1446937 PG 7 WC Zoology SC Zoology GA TU870 UT WOS:A1996TU87000002 ER PT J AU Harp, JM AF Harp, JM TI Bullets and silk in the Old West SO SCIENCE LA English DT Letter C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP Harp, JM (reprint author), UNIV TENNESSEE,OAK RIDGE,TN 37831, USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 SN 0036-8075 J9 SCIENCE JI Science PD FEB 2 PY 1996 VL 271 IS 5249 BP 580 EP 581 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA TT870 UT WOS:A1996TT87000006 ER PT J AU Katsevich, AI Ramm, AG AF Katsevich, AI Ramm, AG TI Consistency of a rank test against general alternatives of change points (surfaces) and continuous trend SO ACTA APPLICANDAE MATHEMATICAE LA English DT Article DE rank test; test of randomness; change points; trend; consistency AB Considered are modifications of a rank test of randomness for the one- and multidimensional regular design cases as well as for the one- and multi-dimensional random design cases. The null hypothesis is that all observations are independent and identically distributed. The main result is the proof of consistency of the test in each of the above cases against two general alternatives. Alternative 1: there exists a pairwise disjoint partition boolean OR(i=1)(m) D-i = D, where D subset of R(d), d greater than or equal to 1, is a bounded domain inside which one makes observations, such that (1) if an observation point falls inside Di, then the corresponding observed value is the realization of a random variable xi(i), i = 1,..., m; (2) there exists an ordering (xi(ik))(k=1)(m), where xi(ik) is stochastically smaller than xi(ik+1), k = 1,..., m-1, (3) the partition is independent of the number of observation points. Note that m, this ordering, and the sets D-i are not known a priori: one tests only for the existence of such a partition. Note also that in the one-dimensional case the initial sequence need not be stochastically monotone under the alternative. Alternative 2: there exists an arbitrary 'asymptotically continuous' trend in location. 'Asymptotically continuous' means that the trend converges to some continuous, not identically constant function as the number of data points goes to infinity. This function need not be monotone. A numerical example illustrating the use of the obtained results for image analysis (edge detection) is presented. C1 LOS ALAMOS NATL LAB,CIC DIV 3,LOS ALAMOS,NM 87545. KANSAS STATE UNIV,DEPT MATH,MANHATTAN,KS 66506. NR 23 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-8019 J9 ACTA APPL MATH JI Acta Appl. Math. PD FEB PY 1996 VL 42 IS 2 BP 105 EP 137 DI 10.1007/BF00047166 PG 33 WC Mathematics, Applied SC Mathematics GA TU175 UT WOS:A1996TU17500001 ER PT J AU Lawson, AC Goldstone, JA Cort, B Martinez, RJ Vigil, FA Zocco, TG Richardson, JW Mueller, MH AF Lawson, AC Goldstone, JA Cort, B Martinez, RJ Vigil, FA Zocco, TG Richardson, JW Mueller, MH TI Structure of zeta-phase plutonium-uranium SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article AB The structure of the zeta-phase in the Pu-U system has been determined by neutron powder diffraction. The phase crystallizes in space group R(3) over barm$ with 58 atoms in the primitive unit cell and 10 atoms in the asymmetric unit. The structure is characterized by many short bonds and fits the general pattern of the light actinides. Thermal expansion and elastic data were obtained from the diffraction experiments. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP Lawson, AC (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 18 TC 16 Z9 16 U1 0 U2 5 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Commun. PD FEB 1 PY 1996 VL 52 BP 32 EP 37 DI 10.1107/S0108768195006811 PN 1 PG 6 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA TZ494 UT WOS:A1996TZ49400003 ER PT J AU Dauskardt, RH Ager, JW AF Dauskardt, RH Ager, JW TI Quantitative stress mapping in alumina composites by optical fluorescence imaging SO ACTA MATERIALIA LA English DT Article ID THERMAL-EXPANSION ANISOTROPY; CARBIDE WHISKER COMPOSITES; CERAMIC-MATRIX COMPOSITES; RAMAN-SPECTROSCOPY; RESIDUAL-STRESSES; AL2O3; SAPPHIRE; POLYCRYSTALS; DIFFRACTION; SHAPE AB Internal residual stresses exist in almost all polycrystalline materials and in many cases exert a profound influence on mechanical and physical behavior. In inherently brittle ceramics and ceramic composites, toughening mechanisms often depend sensitively on localized residual stresses. However, despite their prominence few studies are available which provide a detailed characterization of the local spatial variation of residual stress fields in ceramics and their composites. In this study, we report on the spatially resolved mapping of local residual and applied stresses in polycrystalline alumina and a variety of Al2O3-SiCw composites. Stress mapping is based on the well established method of measuring shifts in the characteristic optical fluorescence lines produced by Cr3+ impurities in the alumina matrix. Novel illumination and imaging optics are used to collect up to 15,000 stress measurements from an area approx. 1 mm(2). Detailed stress maps are generated which produce a vivid and quantitative indication of the complex residual stress fields present in these materials. The additional effect of a non-uniform applied stress field ahead of a blunt notch is also measured. Results are discussed in the context of thermal expansion anisotropy within the alumina phase, thermal expansion differences between the SiC-reinforcement and Al2O3 matrix, and the non-uniform distribution of whiskers. The mean value and fluctuation of the resultant residual stress fields are estimated by extension of recent stochastic mechanics models and compared to measured values. C1 LAWRENCE BERKELEY LAB,DIV SCI MAT,BERKELEY,CA 94720. RP Dauskardt, RH (reprint author), STANFORD UNIV,DEPT MAT SCI & ENGN,STANFORD,CA 94305, USA. OI Ager, Joel/0000-0001-9334-9751 NR 43 TC 17 Z9 17 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB PY 1996 VL 44 IS 2 BP 625 EP 641 DI 10.1016/1359-6454(95)00189-1 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA TY679 UT WOS:A1996TY67900021 ER PT J AU Ceccone, G Nicholas, MG Peteves, SD Tomsia, AP Dalgleish, BJ Glaeser, AM AF Ceccone, G Nicholas, MG Peteves, SD Tomsia, AP Dalgleish, BJ Glaeser, AM TI An evaluation of the partial, transient liquid phase bonding of Si3N4 using Au coated Ni-22Cr foils SO ACTA MATERIALIA LA English DT Article ID SI-N AB The application of the partial transient liquid phase bonding (PTLPB) process for joining silicon nitride ceramics using microdesigned Au/Ni-Cr/Au multilayer interlayers has been investigated. The influence of different bonding parameters, such as time, temperature and interlayer thickness, on the microstructure and chemistry of the ceramic-metal interfaces has been studied. Scanning electron microscopy and electron probe microanalysis investigations revealed that the ceramics were bonded to the Ni-Cr foils by a thin CrN reaction product layer while the Au had alloyed to form a Ni rich solid solution. Joints with room temperature average flexural strength of 272 MPa, were produced under optimized bonding conditions of 4 h at 1000 degrees C. These processing conditions resulted in joints with microstructure and strength equivalent to those obtained by optimized diffusion bonding procedures. The effect of post-bonding annealing in air at 800 degrees C for 60 h on the room temperature joint strength was also assessed. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. RP Ceccone, G (reprint author), JRC,CEC,INST ADV MAT,1755 ZG PETTEN,NETHERLANDS. NR 30 TC 37 Z9 42 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB PY 1996 VL 44 IS 2 BP 657 EP 667 DI 10.1016/1359-6454(95)00187-5 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA TY679 UT WOS:A1996TY67900023 ER PT J AU Williford, RE Henager, CH Hirth, JP AF Williford, RE Henager, CH Hirth, JP TI Matrix creep accommodation in diffusion controlled phase transformations SO ACTA MATERIALIA LA English DT Article ID KINETICS AB Although matrix creep accommodation occurs for a variety of diffusion controlled phase transformations, the focus is usually on the diffusion kinetics. However, interface control of kinetics, associated with the development of elastic stresses at a growing interface, is also possible. The displacement reaction Fe + Cu2O-->FeO + Cu is used as a model system to determine the role of such stresses. The reaction is shown to occur in a regime where the metal matrix phase undergoes either Nabarro-Herring or power law creep. The models developed herein to describe the interface and matrix stresses are tested on several diffusional phase transformations. The general results are that matrix stresses very near growing precipitates are often appreciable. The results have implications for the control of microstructure in in situ composites produced by such reactions. C1 WASHINGTON STATE UNIV, PULLMAN, WA 99164 USA. RP Williford, RE (reprint author), PACIFIC NW LAB, DEPT MAT SCI, MAILSTOP K2-44, RICHLAND, WA 99352 USA. OI Henager, Chuck/0000-0002-8600-6803 NR 24 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB PY 1996 VL 44 IS 2 BP 763 EP 773 DI 10.1016/1359-6454(95)00201-4 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA TY679 UT WOS:A1996TY67900034 ER PT J AU Sinha, SK AF Sinha, SK TI Surface roughness by X-ray and neutron scattering methods SO ACTA PHYSICA POLONICA A LA English DT Article; Proceedings Paper CT II International School and Symposium on Physics in Materials Science Surface and Interface Engineering CY JUL 17-23, 1995 CL JASZOWIEC, POLAND ID MULTILAYER FILMS; THIN-FILMS; INTERFACES AB We discuss how the roughness and morphology of surfaces and interfaces can be characterized by the nondestructive techniques of X-ray and neutron scattering. We first discuss the mathematical description of rough surfaces in terms of correlation functions and then discuss the various kinds of rough surfaces which exist. These fall into the category of self-affine (Gaussian) surfaces, surfaces with capillary wave fluctuations, stepped surfaces, and surfaces with islands or pits. We then discuss how the scattering from such surfaces may be described and which types of information are available from specular reflectivity, off-specular (diffuse) scattering, and grazing incidence reflection experiments, including a comparison with results obtained by other surface techniques. We then discuss multiple rough interfaces and the scattering from thin films and multilayers. Finally, we shall discuss scattering of neutrons by magnetically rough surfaces and multilayers. RP Sinha, SK (reprint author), ARGONNE NATL LAB,EXPT FACIL DIV,ARGONNE,IL 60439, USA. NR 49 TC 21 Z9 21 U1 0 U2 3 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, 02-668 WARSAW, POLAND SN 0587-4246 J9 ACTA PHYS POL A JI Acta Phys. Pol. A PD FEB PY 1996 VL 89 IS 2 BP 219 EP 234 PG 16 WC Physics, Multidisciplinary SC Physics GA UD401 UT WOS:A1996UD40100011 ER PT J AU Prueger, JH Hipps, LE Cooper, DI AF Prueger, JH Hipps, LE Cooper, DI TI Evaporation and the development of the local boundary layer over an irrigated surface in an arid region SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article ID CENTRAL GREAT PLAINS; ADVECTION; EVAPOTRANSPIRATION AB Heterogeneous landscapes common to arid and semi-arid regions are often characterized by a horizontal advection of sensible heat from dry surfaces to wet surfaces which modifies the evaporation and water balance of moist areas. This study centered around a well-watered alfalfa field surrounded locally by arid surfaces, but within a large complex of irrigated fields where both local and regional scale advection were present. Latent and sensible heat flux densities were measured using eddy correlation at four different locations within the same field. Tethered balloons were used to obtain vertical profiles of temperature, humidity, wind speed and direction from the surface to heights of 50 m at the leading and downwind edges of the field. Results show that sensible heat flux and turbulence intensity were strongly correlated indicating the dependence of sensible heat transfer on turbulence. Evaporation in excess of the equilibrium rate was governed by turbulence intensity and the advection of sensible heat. Growth of the local boundary layer above the alfalfa canopy as defined by temperature and humidity profiles averaged about 30 m over a 450 m traverse. The height of the developed local boundary layer was strongly correlated to the intensity of turbulence. Short-term evaporation rates were calculated from the upwind and downwind profiles of humidity and wind, using a modified vapor budget technique, and found to average approximately 10% lower than the measured evaporation rates. The contribution to evaporation from the advection of sensible heat was also calculated from the upwind and downwind profiles and found to range between 28-90% of the total evaporation. C1 UTAH STATE UNIV,LOGAN,UT 84322. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87544. RP Prueger, JH (reprint author), USDA ARS,NATL SOIL TILTH LAB,2150 PAMMEL DR,AMES,IA 50011, USA. OI Hipps, Lawrence/0000-0002-7658-8571 NR 17 TC 24 Z9 25 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD FEB PY 1996 VL 78 IS 3-4 BP 223 EP 237 DI 10.1016/0168-1923(95)02234-1 PG 15 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA UB516 UT WOS:A1996UB51600004 ER PT J AU Lin, YL Bienkowski, PR Shah, VM Cochran, HD AF Lin, YL Bienkowski, PR Shah, VM Cochran, HD TI Extension of a generalized quartic equation of state to pure polar fluids SO AICHE JOURNAL LA English DT Article ID HARD-SPHERE EQUATION; OF-ROTATORS EQUATION; THERMODYNAMIC PROPERTIES AB A generalized four-parameter quartic equation of state (EOS) proposed by Shah and coworkers (1992, 1994) was extended to polar fluids. To use the new generalized quartic EOS for polar fluids, only four characteristic properties of the pure compound are required-critical temperature, critical volume, acentric factor, and dipole moment. For nonpolar fluids, the previous equation is recovered and its superior performance for nonpolar fluids is retained. A new set of coefficients for polar fluids for the EOS was determined from multiproperty regressions using literature data for various physical and thermodynamic experimental properties of 30 pure compounds. These regressed coefficients, which are functions of the critical temperature, critical pressure, acentric factor, and the dipole moment of the fluid, were generalized. The accuracy of this equation of state is evaluated with the new set of regressed coefficients to predict thermodynamic properties of pure polar compounds, including vapor pressure, density residual enthalpy, enthalpy of vaporization, and second virial coefficient. The capability and accuracy of this quartic equation of state are also compared with the well-known Peng-Robinson EOS. C1 UNIV TENNESSEE,KNOXVILLE,TN 37909. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 37 TC 6 Z9 6 U1 1 U2 7 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD FEB PY 1996 VL 42 IS 2 BP 562 EP 570 DI 10.1002/aic.690420225 PG 9 WC Engineering, Chemical SC Engineering GA TU829 UT WOS:A1996TU82900024 ER PT J AU Chialvo, AA Kalyuzhnyi, YV Cummings, PT AF Chialvo, AA Kalyuzhnyi, YV Cummings, PT TI Solvation thermodynamics of gas solubility at sub- and near-critical conditions SO AICHE JOURNAL LA English DT Article ID MEAN SPHERICAL APPROXIMATION; ORNSTEIN-ZERNIKE EQUATION; CRITICAL-BEHAVIOR; CRITICAL-POINT; MIXTURES; FLUID; SIMULATION; CONSTANTS AB The recently developed formalism for describing the solute-induced effect in dilute near-critical mixtures is extended to fluids composed of anisotropic molecules through the statistical mechanical interpretation of the derivative (partial derivative P/partial derivative x(2))(T,rho)(infinity) whose critical value is the Krichevskii parameter. Rigorous expressions for Henry's constant and the solute distribution factor along the orthobaric curve are derived in terms of the volumetric and entropic solute-induced local effects, and the quasi-linear behavior of their orthobaric density dependence away from the solvent's critical point is rationalized. The formalism is illustrated with integral equation calculations of the orthobaric density dependence of several solvation thermodynamic quantities for an infinitely dilute volatile solute in near-critical solutions of hard-sphere Yukawa fluids. C1 UNIV TENNESSEE,DEPT CHEM ENGN,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. YV KALYUZHNYI INST CONDENSED MAT PHYS,LVOV 290011,UKRAINE. RI Cummings, Peter/B-8762-2013; OI Cummings, Peter/0000-0002-9766-2216; Chialvo, Ariel/0000-0002-6091-4563 NR 37 TC 23 Z9 23 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD FEB PY 1996 VL 42 IS 2 BP 571 EP 584 DI 10.1002/aic.690420226 PG 14 WC Engineering, Chemical SC Engineering GA TU829 UT WOS:A1996TU82900025 ER PT J AU Jiang, SY Pitzer, KS AF Jiang, SY Pitzer, KS TI Phase equilibria and volumetric properties of aqueous CaCl2 by an equation of state SO AICHE JOURNAL LA English DT Article ID THERMODYNAMIC PERTURBATION-THEORY; SYNTHETIC FLUID INCLUSIONS; CALCIUM-CHLORIDE; MIXTURES; TEMPERATURES; SYSTEMS; REPRESENTATION; PRESSURES; DENSITIES; 573-K AB A comprehensive equation of state was developed to represent the phase equilibria and volumetric properties of aqueous calcium chloride solutions at temperatures above 523 K. The equation consists of a reference part and a perturbation contribution. The reference function is developed from the statistical mechanical theory for mixtures of dipolar and quadrupolar hard spheres, which agrees well with the Monte Carlo simulation results. In this treatment calcium chloride is described by the completely undissociated model. The empirical perturbation function is a truncated series of virial expansion terms. Thus, mixing rules are guided by those of virial coefficients, which are derived rigorously from statistical mechanics. The equation reproduces experimental saturated vapor pressures and volumetric data within experimental uncertainty for temperatures to 623 K. At higher temperatures, few and less accurate experimental data are available, but values of the saturated vapor pressures of the liquid have been reported and are represented satisfactorily. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 43 TC 21 Z9 22 U1 1 U2 2 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0001-1541 J9 AICHE J JI AICHE J. PD FEB PY 1996 VL 42 IS 2 BP 585 EP 594 DI 10.1002/aic.690420227 PG 10 WC Engineering, Chemical SC Engineering GA TU829 UT WOS:A1996TU82900026 ER PT J AU Dixon, RK Sathaye, JA Meyers, SP Masera, OR Makarov, AA Toure, S Makundi, W Wiel, S AF Dixon, RK Sathaye, JA Meyers, SP Masera, OR Makarov, AA Toure, S Makundi, W Wiel, S TI Greenhouse gas mitigation strategies: Preliminary results from the US Country Studies Program SO AMBIO LA English DT Article AB Under the UN Framework Convention on Climate Change (UNFCCC), developing and transition countries are eventually required to report greenhouse gas (GHG) emissions inventories and response (mitigation) options. The United States (US) and other donors are providing financial and technical support for climate change country studies to help meet their needs under the UNFCCC. Technical assistance to complete mitigation assessments includes training of analysts, sharing of contemporary tools and assessment techniques, implementation of information-sharing workshops, and an exchange program for analysts. Country analysts have access to more than 25 analytical tools to help them complete their GHG mitigation assessments. Preliminary assessments suggest that GHG stabilization strategies should focus on fossil-fuel combustion, the primary source of carbon dioxide (CO2) emissions, and on forest management to sequester or conserve carbon (C). In selected countries, mitigation of methane (CH4) emissions from rice paddy, livestock production, and waste management are also considered relevant response options. Strengthening of human and institutional capacity to cope with global climate change issues will provide developing and transition countries with a sustained basis for meeting the goals of the UNFCCC. C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV NACL AUTONOMA MEXICO,CTR ECOL,MEXICO CITY 04510,DF,MEXICO. RUSSIAN ACAD SCI,ENERGY RES INST,MOSCOW 117333,RUSSIA. MINIST ENSEIGNMENT SUPER & RECH SCI COTE IVORIE,ABIDJAN,COTE IVOIRE. RP Dixon, RK (reprint author), US COUNTRY STUDIES PROGRAM,PO-63,1000 INDEPENDENCE AVE SW,WASHINGTON,DC 20585, USA. NR 40 TC 12 Z9 13 U1 1 U2 1 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0044-7447 J9 AMBIO JI Ambio PD FEB PY 1996 VL 25 IS 1 BP 26 EP 32 PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA TX840 UT WOS:A1996TX84000006 ER PT J AU Drennan, PM Nobel, PS AF Drennan, PM Nobel, PS TI Temperature influences on root growth for Encelia farinosa (Asteraceae), Pleuraphis rigida (Poaceae), and Agave deserti (Agavaceae) under current and doubled CO2 concentrations SO AMERICAN JOURNAL OF BOTANY LA English DT Article DE climate change; desert; interspecific competition; niche; root elongation rate; rooting depth; soil temperature ID WATER RELATIONS; CARBON-DIOXIDE; HILARIA-RIGIDA; ELEVATED CO2; CAM PLANT; COMPETITION; SUCCULENTS; RESPONSES; C-4 AB To help evaluate root distribution patterns, elongation rates of individual roots were measured as a function of soil temperature for Encelia farinosa (a C-3 species), Pleuraphis rigida (C-4), and Agave deserti (CAM), sympatric codominants in the northwestern Sonoran Desert. Measurements were made at current and doubled CO2 concentrations under winter and summer conditions of air temperature (day/night temperatures of 17 C/10 C and 33 C/22 C, respectively). The three species had different optimal temperatures for root elongation (T-opt) under winter conditions (25 C for E. farinosa, 35 C for P. rigida, and 30 C for A. deserti); T-opt increased by 2-3 C under summer conditions for all three species. The limiting temperatures for elongation also acclimated from winter to summer conditions. The rate of root elongation at T-opt was higher under summer than winter conditions for E. farinosa (3 vs. 6 mm d(-1)) and P. rigida (20 vs. 14 mm d(-1)), reflecting conditions for maximum photosynthesis; no difference occurred for A. deserti (9 vs. 10 mm d(-1)). Decreased elongation rates at extreme temperatures were associated with less cell division and reduced cell extension. The doubled CO2 concentration increased average daily root elongation rates for A. deserti under both winter (7%) and summer (12%) conditions, reflecting increased cell extension, but had no effect for the other two species. Simulations of root elongation as a function of soil temperatures showed that maximum elongation would occur at different depths (16-20 cm for E. farinosa, 4-8 cm for P. rigida, and 0-4 cm for A. deserti) and during different seasons (winter to spring for E. farinosa, spring to summer for P. rigida, and all year for A. deserti), contributing to their niche separation. Shading of the soil surface moderated daily variations in soil temperature, reducing seasonal root elongation for winter and spring and increasing elongation for summer. Shading also altered root distribution patterns, e.g., optimal rooting depth for A. deserti and especially P. rigida increased for a hot summer day. C1 UNIV CALIF LOS ANGELES,DEPT BIOL,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,DOE LAB,LOS ANGELES,CA 90024. NR 49 TC 21 Z9 24 U1 0 U2 7 PU BOTANICAL SOC AMER INC PI COLUMBUS PA OHIO STATE UNIV-DEPT BOTANY 1735 NEIL AVE, COLUMBUS, OH 43210 SN 0002-9122 J9 AM J BOT JI Am. J. Bot. PD FEB PY 1996 VL 83 IS 2 BP 133 EP 139 DI 10.2307/2445929 PG 7 WC Plant Sciences SC Plant Sciences GA TW240 UT WOS:A1996TW24000001 ER PT J AU Takayama, K Salazar, EP Broughton, BC Lehmann, AR Sarasin, A Thompson, LH Weber, CA AF Takayama, K Salazar, EP Broughton, BC Lehmann, AR Sarasin, A Thompson, LH Weber, CA TI Defects in the DNA repair and transcription gene ERCC2(XPD) in trichothiodystrophy SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Article ID XERODERMA-PIGMENTOSUM; SACCHAROMYCES-CEREVISIAE; COMPLEMENTATION GROUP; ULTRAVIOLET-LIGHT; HELICASE; CLONING; HETEROGENEITY; DISORDER; RAD3 AB Trichothiodystrophy (TTD) is a rare autosomal recessive disorder characterized by brittle hair with reduced sulfur content, ichthyosis, peculiar face, and mental and growth retardation. Clinical photosensitivity is present in similar to 50% of TTD patients but is not associated with an elevated frequency of cancers. Previous complementation studies show that the photosensitivity in nearly all of the studied patients is due to a defect in the same genetic locus that underlies the cancer-prone genetic disorder xeroderma pigmentosum group D (XP-D). Nucleotide-sequence analysis of the ERCC2 cDNA from three TTD cell strains (TTD1VI, TTD3VI, and TTD1RO) revealed mutations within the region from amino acid 713-730 and within previously identified helicase functional domains. The various clinical presentations and DNA repair characteristics of the cell strains can be correlated with the particular mutations found in the ERCC2 locus. Mutations of Arg658 to either His or Cys correlate with TTD cell strains with intermediate UV-sensitivity, mutation of Arg722 to Trp correlates with highly UV-sensitive TTD cell strains, and mutation of Arg683 to Trp correlates with XP-D. Alleles with mutation of Arg616 to Pro or with the combined mutation of Leu461 to Val and deletion of 716-730 are found in both XP-D and TTD cell strains. C1 LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM,LIVERMORE,CA 94551. UNIV SUSSEX,MRC,CELL MUTAT UNIT,BRIGHTON BN1 9RR,E SUSSEX,ENGLAND. INST RECH SCI CANC,GENET MOLEC LAB,VILLEJUIF,FRANCE. FU NCI NIH HHS [CA52679] NR 39 TC 75 Z9 76 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD FEB PY 1996 VL 58 IS 2 BP 263 EP 270 PG 8 WC Genetics & Heredity SC Genetics & Heredity GA TR791 UT WOS:A1996TR79100002 PM 8571952 ER PT J AU Watanabe, M Zingg, BC Mohrenweiser, HW AF Watanabe, M Zingg, BC Mohrenweiser, HW TI Molecular analysis of a series of alleles in humans with reduced activity at the triosephosphate isomerase locus SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Article ID DIHYDROFOLATE-REDUCTASE PROMOTER; PROLIFERATION SPECIFIC ISOZYME; TRANSCRIPTION INITIATION; PROCESSED PSEUDOGENES; HIP1 BINDING; ENZYME; DEFICIENCY; SITE; POLYMERASE; MUTATIONS AB Individuals with 50% of expected triosephosphate isomerase (TPI) enzyme activity have been previously identified in families during the screening of similar to 2,000 newborn children for quantitative variation in activity of 12 erythrocyte enzymes. The frequency of the trait was 9/1,713 individuals in the Caucasian population and 7/168 individuals among the African-American population studied. Genetic transmission of the trait was confirmed in all families. The frequency of the presumptive deficiency allele(s) at the TPI locus was greater than expected, given the reported incidence of clinical TPI deficiency. We report the molecular characterization of the variant alleles from seven African-American and three Caucasian individuals in this group of unrelated individuals. Three amino acid substitutions - a Gly-->Ala substitution at residue 72, a Val-->Met at residue 154, and a previously described Glu-->Asp substitution at residue 104 - were identified in the Caucasian individuals. The substitutions occur at residues that are not directly involved in the active site but are highly conserved through evolutionary time, suggesting important roles for these residues in maintenance of subunit structure and conformation. The variant allele in the seven African-American individuals had nucleotide changes at positions -8 and -5 (5' of) from the transcription-initiation site. In three of these individuals, an additional T-->G substitution was detected in a TATA box-like sequence located 24 nucleotides 5' of the transcription-initiation site and on the same chromosome as the -5/-8 substitutions, Thus, molecular alterations at the TPI locus were detected in 10 unrelated individuals in whom segregation of a phenotype of reduced TPI activity previously had been identified. C1 LAWRENCE LIVERMORE NATL LAB,BIOL & BIOTECHNOL RES PROGRAM L452,LIVERMORE,CA 94550. NR 41 TC 30 Z9 34 U1 2 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD FEB PY 1996 VL 58 IS 2 BP 308 EP 316 PG 9 WC Genetics & Heredity SC Genetics & Heredity GA TR791 UT WOS:A1996TR79100007 PM 8571957 ER PT J AU Wangler, TP AF Wangler, TP TI Strong focusing and the radiofrequency quadrupole accelerator SO AMERICAN JOURNAL OF PHYSICS LA English DT Article RP Wangler, TP (reprint author), LOS ALAMOS NATL LAB,ACCELERATOR OPERAT & TECHNOL DIV,LOS ALAMOS,NM 87545, USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD FEB PY 1996 VL 64 IS 2 BP 177 EP 182 DI 10.1119/1.18300 PG 6 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA UG701 UT WOS:A1996UG70100021 ER PT J AU BonchinCleland, SL Cleland, TJ Olson, LK Caruso, JA AF BonchinCleland, SL Cleland, TJ Olson, LK Caruso, JA TI Evaluation of a modified ion lens system for inductively coupled plasma-mass spectrometry SO AMERICAN LABORATORY LA English DT Article AB A modification to the ion lens in an ICP-MS instrument that improves ion transport to the detector is described in this article. The result of this step is a significant improvement in sensitivity. RP BonchinCleland, SL (reprint author), LOS ALAMOS NATL LAB,INORGAN TRACE ANAL GRP,CHEM SCI & TECHNOL DIV,CST-9 MS J514,LOS ALAMOS,NM 87545, USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU INT SCIENTIFIC COMMUN INC PI SHELTON PA PO BOX 870, 30 CONTROLS DRIVE, SHELTON, CT 06484-0870 SN 0044-7749 J9 AM LAB JI Am. Lab. PD FEB PY 1996 VL 28 IS 3 BP P34 EP & PG 5 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA TW067 UT WOS:A1996TW06700008 ER PT J AU Bruce, JE Anderson, GA Smith, RD AF Bruce, JE Anderson, GA Smith, RD TI ''Colored'' noise waveforms and quadrupole excitation for the dynamic range expansion of Fourier transform ion cyclotron resonance mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID ELECTROSPRAY-IONIZATION; LARGE BIOMOLECULES; LASER DESORPTION; SPECTROSCOPY; MOLECULES; TRAP AB Fourier transform ion cyclotron resonance (FTICR) mass spectrometry offers unparalleled analytical performance in most regards but has a dynamic range of typically no better than 10(2)-10(3), This limitation reportedly arises from two opposing constraints, involving the maximum number of ions that can be effectively trapped (10(6)-10(7)) and the minimum number of ions required to produce a detectable signal (10(2)-10(3)), A potential solution to this dynamic range limitation is presented, based on the application of selected-ion accumulation using quadrupole excitation, We show that lower concentration species can be effectively accumulated in the FTICR trapped ion cell, while the more abundant species are continually removed by the application of quadrupolar excitation in the form of band-limited or ''colored'' noise waveforms, The result is that ''room'' is made in the cell for lower abundance species, even during extended accumulation periods, This approach was demonstrated with mixtures of the bovine proteins, insulin, ubiquitin, and cytochrome c, For normal accumulation, the dynamic range was similar to 100, The application of selected-ion accumulation in the form of colored noise allowed the extension by 2 orders of magnitude and the detection of species of 1 x 10(-8) M concentration from a solution also containing another component at 9 x 10(-)5 M. With this method, a putative new low abundance variant of bovine insulin was observed, and selected-ion accumulation and subsequent collisionally activated dissociation were used for its identification. Dipolar magnetron excitation was also explored to enhance selected-ion accumulation and was found to reduce the amount of buffer gas required for complete removal of the undesired species by a factor of 5. Further possible improvements are discussed, as are the complications due to the required balance between magnetron and cyclotron damping rates. C1 PACIFIC NW NATL LAB,DEPT CHEM SCI,RICHLAND,WA 99352. PACIFIC NW NATL LAB,ENVIRONM MOLEC SCI LAB,RICHLAND,WA 99352. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 NR 43 TC 48 Z9 48 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD FEB 1 PY 1996 VL 68 IS 3 BP 534 EP 541 DI 10.1021/ac950823k PG 8 WC Chemistry, Analytical SC Chemistry GA TR964 UT WOS:A1996TR96400018 PM 8712362 ER PT J AU Watson, CH Barshick, CM Wronka, J Laukien, FH Eyler, JR AF Watson, CH Barshick, CM Wronka, J Laukien, FH Eyler, JR TI Pulsed gas glow discharge for ultrahigh mass resolution measurements with Fourier transform ion cyclotron resonance mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID FT-ICR; SOLIDS AB A new pulsed-gas glow discharge (GD) source has been developed for use with an external ion source Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. With pulsed argon gas introduction into the GD source, the gas load and pressure in the mass analyzer region were greatly reduced; this resulted in improved mass resolution. Mass resolution of greater than 1 450 000 (fwhm) has been achieved for Cu+ ions from a brass sample, the highest reported for any type of GD mass spectrometer. The pulsed-gas GD source promises analytical usefulness for ultrahigh resolution measurements in GD mass spectrometry. C1 OAK RIDGE NATL LAB,DIV CHEM & ANALYT SCI,OAK RIDGE,TN 37831. BRUKER ANALYT SYST INC,MASS SPECTROMETRY DIV,BILLERICA,MA 01821. RP Watson, CH (reprint author), UNIV FLORIDA,DEPT CHEM,POB 117200,GAINESVILLE,FL 32611, USA. NR 16 TC 14 Z9 14 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD FEB 1 PY 1996 VL 68 IS 3 BP 573 EP 575 DI 10.1021/ac9508412 PG 3 WC Chemistry, Analytical SC Chemistry GA TR964 UT WOS:A1996TR96400025 PM 21619092 ER PT J AU Milan, SE Jones, TB Lester, M Warrington, EM Reeves, GD AF Milan, SE Jones, TB Lester, M Warrington, EM Reeves, GD TI Substorm correlated absorption on a 3200 km trans-auroral HF propagation path SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article ID MAGNETOSPHERIC SUBSTORMS; MAGNETIC-FIELD; MAGNITUDE; ORBIT AB A high-frequency transmitter located at Clyde River, NWT, Canada, and a receiver located near Boston, USA, provide a 3200 km trans-auroral, near-meridional propagation path over which the propagation characteristics have been measured. Out of the fourteen frequencies in the HF band sampled every hour for the duration of the experimental campaign (16 January-8 February 1989), the signal level measurements of 6.800 MH transmissions were selected in order to determine the extent and occurrence of auroral absorption. The median level of auroral absorption along the path is found to increase with geomagnetic activity, quantified by the index K-p, with the increase being greater in the post-midnight sector than in the pre-midnight sector. This asymmetric behaviour is attributed to the precipitation of high energy electrons into the midnight and morning sector auroral D region. The measured diurnal variation in the median level of absorption is consistent with previous models describing the extent and magnitude of auroral absorption and electron precipitation. Individual substorms, identified from geosynchronous satellite data, are found to cause short-lived absorption events in the HF signal level of similar to 30 dB at 6.800 MHz. The occurence of substorm correlated auroral absorption events is confined to the midnight and morning sectors, consistent with the location of the electron precipitation. The magnitude of absorption is related to the magnetotail stress during the substorm growth phase and the magnetotail relaxation during the substorm expansion phase onset. The absorption magnitude and the occurrence of substorms during the period of the campaign increase at times of high K,. leading to an increase in median auroral absorption during disturbed periods. C1 LOS ALAMOS NATL LAB,DIV SPACE SCI,LOS ALAMOS,NM 87545. RP Milan, SE (reprint author), UNIV LEICESTER,DEPT PHYS & ASTRON,UNIV RD,LEICESTER LE1 7RH,LEICS,ENGLAND. RI Reeves, Geoffrey/E-8101-2011; OI Reeves, Geoffrey/0000-0002-7985-8098; Warrington, Michael/0000-0001-6505-7380 NR 25 TC 23 Z9 23 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0992-7689 J9 ANN GEOPHYS JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD FEB PY 1996 VL 14 IS 2 BP 182 EP 190 DI 10.1007/s00585-996-0182-8 PG 9 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA TV324 UT WOS:A1996TV32400005 ER PT J AU North, GB Nobel, PS AF North, GB Nobel, PS TI Radial hydraulic conductivity of individual root tissues of Opuntia ficus-indica (L) Miller as soil moisture varies SO ANNALS OF BOTANY LA English DT Article DE Opuntia ficus-indica; prickly pear; root hydraulic conductivity; endodermis; periderm; apoplast; lateral root emergence ID ZEA-MAYS L; WATER TRANSPORT; HYPODERMAL LAYERS; CORTICAL-CELLS; PERMEABILITY; MOVEMENT; CONDUCTANCE; PATHWAYS; PERIDERM; ANATOMY AB The constraints on water uptake imposed by individual root tissues were examined for Opuntia ficus-indica under wet, drying, and rewetted soil conditions. Root hydraulic conductivity (L(p)) and axial conductance (K-h) were measured for intact root segments from the distal region with an endodermis and from midroot with a periderm; Lp( )was then measured for each segment with successive tissues removed by dissection. Radial conductivity (L(R)) was calculated from L(p) and K-h for the intact segment and for the individual tissues by considering the tissue conductivities in series. Under wet conditions, L(R) for intact distal root segments was lowest for the cortex; at midroot, where cortical cells are dead, L(R) for the cortex was higher and no single tissue was the predominant limiter of L(R). L(R) for the endodermis and the periderm were similar under wet conditions. During 30 d of soil drying, L(R) for the distal cortex increased almost three-fold due to the death of cortical cells, whereas L(R) for the midroot cortex was unaffected; L(R) for the endodermis and the periderm decreased by 40 and 90%, respectively, during drying. For both root regions under wet conditions, the vascular cylinder had the highest L(R), which decreased by 50-70% during 30 d of soil drying. After 3 d of rewetting. new lateral roots emerged, increasing L(R) for the tissues outside the vascular cylinder as well as increasing uptake of an apoplastic tracer into the xylem of both the roots and the shoot. The average L(R) for intact root segments was similar under wet and rewetted conditions, but the conductivity of the tissues outside the vascular cylinder increased after rewetting, as did the contribution of the apoplastic pathway to water uptake. (C) 1996 Annals of Botany Company C1 UNIV CALIF LOS ANGELES,DOE LAB,LOS ANGELES,CA 90024. UNIV CALIF LOS ANGELES,DEPT BIOL,LOS ANGELES,CA 90024. NR 47 TC 39 Z9 49 U1 0 U2 5 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 0305-7364 J9 ANN BOT-LONDON JI Ann. Bot. PD FEB PY 1996 VL 77 IS 2 BP 133 EP 142 DI 10.1006/anbo.1996.0015 PG 10 WC Plant Sciences SC Plant Sciences GA TW936 UT WOS:A1996TW93600003 ER PT J AU Ashby, SF Lee, SL Petzold, LR Saylor, PE Seidel, E AF Ashby, SF Lee, SL Petzold, LR Saylor, PE Seidel, E TI Computing spacetime curvature via differential algebraic equations SO APPLIED NUMERICAL MATHEMATICS LA English DT Article; Proceedings Paper CT Workshop on the Method of Lines for Time-Dependent Problems CY MAY 31-JUN 04, 1995 CL LEXINGTON, KY SP Natl Sci Fdn, Univ Kentucky, Ctr Computat Sci, So Methodist Univ, Dedman Coll, Colorado Sch Mines AB The equations that govern the behavior of physical systems can often be solved numerically using a method of lines approach and differential algebraic equation (DAE) solvers. For example, such an approach can be used to solve the Einstein field equations of general relativity, and thereby simulate significant astrophysical events. In this paper, we describe some preliminary work in which two model problems in general relativity are formulated, spatially discretized, and then numerically solved as a DAE. In particular, we seek to reproduce the solution to the spherically symmetric Schwarzschild spacetime. This is an important testbed calculation in numerical relativity since the solution is the steady-state for the collision of two (or more) nonrotating black holes. Moreover, analytic late-time properties of the Schwarzschild spacetime are well known and can be used to verify the accuracy of the simulation. C1 OAK RIDGE NATL LAB,DIV COMP SCI & MATH,OAK RIDGE,TN 37830. LAWRENCE LIVERMORE NATL LAB,CTR COMPUTAT SCI & ENGN,LIVERMORE,CA 94550. UNIV MINNESOTA,DEPT COMP SCI,MINNEAPOLIS,MN 55455. UNIV ILLINOIS,DEPT COMP SCI,URBANA,IL 61801. UNIV ILLINOIS,NATL CTR SUPERCOMP APPLICAT,URBANA,IL 61801. UNIV ILLINOIS,DEPT PHYS,URBANA,IL 61801. NR 9 TC 0 Z9 0 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD FEB PY 1996 VL 20 IS 1-2 BP 221 EP 234 DI 10.1016/0168-9274(95)00128-X PG 14 WC Mathematics, Applied SC Mathematics GA UF184 UT WOS:A1996UF18400016 ER PT J AU Yamamoto, KY Cremers, DA Ferris, MJ Foster, LE AF Yamamoto, KY Cremers, DA Ferris, MJ Foster, LE TI Detection of metals in the environment using a portable laser-induced breakdown spectroscopy instrument SO APPLIED SPECTROSCOPY LA English DT Article DE laser-induced breakdown spectroscopy; laser spark; metals analysis; soils ID SPECTROMETRY; SPARK AB A portable instrument, based on laser-induced breakdown spectroscopy (LIES), has been developed for the detection of metal contaminants on surfaces. The instrument has a weight of 14.6 kg, fits completely into a small suitcase (46 x 33 x 24 cm), and operates from 115 V ac. The instrument consists of a sampling probe connected to the main analysis unit by electrical and optical cabling. The hand-held probe contains a small laser to generate laser sparks on a surface and a fiber-optic cable to collect the spark light. The collected light is spectrally resolved and detected with the use of a compact spectrograph/CCD detector system. The instrument has been evaluated for the analysis of metals in the environment: Ba, Be, Pb, and Sr in soils; Pb in paint; and Be and Pb particles collected on filters. Detection limits in ppm for metals in soils were 265 (Ba), 9.3 (Be), 298 (Pb), and 42 (Sr). The detection limit for Pb in paint was 0.8% (8000 ppm), corresponding to 0.052 mg/cm(2). The higher limit obtained for Pb in paint is attributed to the use of the 220.35-nm Pb(II) line instead of the stronger 405.78-nm Pb(I) line used for soils. Spectral interferences prevented use of the 405.78-nm line to determine Pb in paint. The surface detection limit for Be particles on filters was dependent on particle size and ranged from 21 to 63 ng/cm(2). The detection limit for Pb particles on filters was 5.6 mu g/cm(2). C1 LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,LOS ALAMOS,NM 87545. NR 30 TC 205 Z9 214 U1 1 U2 21 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD FEB PY 1996 VL 50 IS 2 BP 222 EP 233 DI 10.1366/0003702963906519 PG 12 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA TV879 UT WOS:A1996TV87900015 ER PT J AU Campiglia, AD Hueber, DM Vo-Dinh, T AF Campiglia, AD Hueber, DM Vo-Dinh, T TI Laser-induced solid-surface room-temperature phosphorimetry of polycyclic aromatic hydrocarbons SO APPLIED SPECTROSCOPY LA English DT Article DE RTP; laser-induced SSRTP; PAHs; low-background substrate ID HEAVY-ATOM; PHOSPHORESCENCE; CARBARYL; PAPER AB Laser-induced solid-surface room-temperature phosphorimetry (SSRTP) has been employed for the detection of polycyclic aromatic hydrocarbons. A nitrogen-pumped laser and a dye laser were used as excitation sources. The effects of sample volume, laser irradiation, and background reduction treatment on the precision and sensitivity of the method were studied. With the use of thallium(I) acetate as a phosphorescence enhancer, picogram limits of detection were estimated for phenanthrene, pyrene, benzo[g,h,i]perylene, chrysene, coronene, and 1,2-benzofluorene. The study demonstrates that laser excitation can improve the sensitivity of SSRTP by up to three orders of magnitude. C1 OAK RIDGE NATL LAB, ADV MONITORING DEV GRP, HLTH SCI RES DIV, OAK RIDGE, TN 37830 USA. UNIV BRASILIA, DEPT QUIM, BR-70910900 BRASILIA, DF, BRAZIL. NR 28 TC 12 Z9 12 U1 1 U2 5 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 5320 SPECTRUM DRIVE SUITE C, FREDERICK, MD 21703 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD FEB PY 1996 VL 50 IS 2 BP 252 EP 256 DI 10.1366/0003702963906401 PG 5 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA TV879 UT WOS:A1996TV87900019 ER PT J AU Funk, DJ Breshears, WD Laabs, GW Asay, BW AF Funk, DJ Breshears, WD Laabs, GW Asay, BW TI Laser diode reflectometry and infrared emission measurements of permeating gases at high driving pressures and temperatures SO APPLIED SPECTROSCOPY LA English DT Article DE laser diode reflectometry; transient infrared absorption; high explosives AB We report the use of infrared diode lasers in a diffuse reflection geometry for detection of the cyclotetramethylentetranitramine (HMX) combustion product CO permeating through a silicon carbide bed. We find that infrared emission and transient absorption are coincident with these pressure waves and demonstrate the feasibility of these diagnostics for detecting molecular species in hostile environments. We conclude from the experimental evidence that macroscopic convective heating may play a limited role in the deflagration-to-detonation transition (DDT) of porous explosives. C1 LOS ALAMOS NATL LAB,EXPLOS TECHNOL & SAFETY GRP,DYNAM EXPERIMENTAT DIV,LOS ALAMOS,NM 87545. RP Funk, DJ (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,CST-6,MS J567,LOS ALAMOS,NM 87545, USA. NR 12 TC 3 Z9 3 U1 1 U2 2 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA PO BOX 1438, FREDERICK, MD 21701 SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD FEB PY 1996 VL 50 IS 2 BP 257 EP 262 DI 10.1366/0003702963906555 PG 6 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA TV879 UT WOS:A1996TV87900020 ER PT J AU Jagoe, CH Faivre, A Newman, MC AF Jagoe, CH Faivre, A Newman, MC TI Morphological and morphometric changes in the gills of mosquitofish (Gambusia holbrooki) after exposure to mercury (II) SO AQUATIC TOXICOLOGY LA English DT Article DE mercury; chloride cells; gill epithelium; SEM; stereology; autometallography ID TROUT SALMO-GAIRDNERI; FRESH-WATER FISH; RAINBOW-TROUT; SALVELINUS-FONTINALIS; SECONDARY LAMELLAE; INORGANIC MERCURY; ACID WATER; LOW PH; ONCORHYNCHUS-MYKISS; PLATICHTHYS-FLESUS AB Physiological measurements suggest that mercury (Hg) affects ion regulation in aquatic organisms. This implies that Hg should cause morphological changes in gills, the major ionoregulatory organ of fish. Previous studies have shown severe Hg-induced gill damage at acutely lethal Hg concentrations, but in soft fresh waters, where ionoregulatory disturbances should be most pronounced, there have been no quantitative studies to date of the effects of dissolved Hg at sublethal concentrations. We exposed mosquitofish (Gambusia holbrooki) to nominal concentrations of 75, 150 and 300 nM Hg (II) in natural stream water of low ionic strength (Ca = 4.8 mu M) in a static-renewal experiment. Mercury concentrations dropped rapidly after Hg additions, and most dissolved Hg was probably complexed with humic substances. Gills were sampled after 7 and 14 days exposure. Examination with scanning electron microscopy (SEM), indicated that Hg caused progressive loss of secondary lamellae and loss of cell surface microridges. Effects became more severe at higher Hg concentrations. Using light microscopy and morphometric techniques, the percent of gill filament occupied by chloride cells (volume density) was significantly greater in all Hg treatments than in controls, and thickness of the primary lamellar epithelium increased with Hg exposure. Thickening of the primary lamellar epithelium filled some interlamellar spaces, obliterating secondary lamellae. However, width of the exposed portions of secondary lamellae was not affected by Hg, suggesting that blood-to-water diffusion distances did not increase in response to Hg exposure. Autometallographic staining for Hg showed that the metal was distributed throughout the gill epithelium, and not concentrated inside chloride cells. RP Jagoe, CH (reprint author), UNIV GEORGIA, SAVANNAH RIVER ECOL LAB, PO DRAWER E, AIKEN, SC 29802 USA. NR 69 TC 30 Z9 35 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD FEB PY 1996 VL 34 IS 2 BP 163 EP 183 DI 10.1016/0166-445X(95)00033-Z PG 21 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA TX401 UT WOS:A1996TX40100006 ER PT J AU Cushing, CE AF Cushing, CE TI The ecology of cold desert spring-streams SO ARCHIV FUR HYDROBIOLOGIE LA English DT Article ID PARTICULATE ORGANIC-MATTER; BENTHIC INSECTS; STABLE ISOTOPES; ECOSYSTEMS; INVERTEBRATES; BIOENERGETICS; INPUTS; FLOW AB Cold desert spring-streams exhibit several features which make their structure and function unusual as compared to more mesic systems. These include anomalies between autotrophy and export, low macroinvertebrate populations probably related to severe winter spates, and secondary production rates intermediate between mesic streams and hot desert streams. RP Cushing, CE (reprint author), PACIFIC NW LAB, ECOL GRP, POB 999, RICHLAND, WA 99352 USA. NR 67 TC 11 Z9 11 U1 0 U2 5 PU E SCHWEIZERBART'SCHE VERLAGS PI STUTTGART PA NAEGELE U OBERMILLER JOHANNESSTRASSE 3A, D 70176 STUTTGART, GERMANY SN 0003-9136 J9 ARCH HYDROBIOL JI Arch. Hydrobiol. PD FEB PY 1996 VL 135 IS 4 BP 499 EP 522 PG 24 WC Limnology; Marine & Freshwater Biology SC Marine & Freshwater Biology GA TY052 UT WOS:A1996TY05200005 ER PT J AU Timmes, FX Woosley, SE Weaver, TA AF Timmes, FX Woosley, SE Weaver, TA TI The neutron star and black hole initial mass function SO ASTROPHYSICAL JOURNAL LA English DT Article DE black hole physics; stars, evolution; stars, luminosity function, mass function; stars, neutron; stars, statistics ID ELECTRON-CAPTURE SUPERNOVAE; 8-10 M. STARS; WHITE-DWARFS; MILLISECOND PULSARS; BINARY PULSAR; PSR 1913+16; COLLAPSE; EVOLUTION; MODELS; HELIUM AB Using recently calculated models for massive stellar evolution and supernovae coupled to a model for Galactic chemical evolution, neutron star and black hole birth functions (number of neutron stars and black holes as a function of their mass) are determined for the Milky Way galaxy. For those stars that explode as Type II supernovae, the models give birth functions that are bimodal with peaks at 1.27 and 1.76 M(.) and average masses within those peaks of 1.28 and 1.73 M(.). For these stars that explode as Type Ib there is a narrower spread of remnant masses, the average being 1.32 M(.), and less evidence for bimodality. These values will be increased, especially in the more massive Type II supernovae, if significant accretion continues during the initial launching of the shock, and the number of heavier neutron stars could be depleted by black hole formation. The principal reason for the dichotomy in remnant masses for Type II is the difference in the presupernova structure of stars above and below 19 M(.), the mass separating stars that burn carbon convectively from those that produce less carbon and burn radiatively. The Type Ib's and the lower mass group of the Type II's compare favorably with measured neutron star masses, and in particular to the Thorsett et al. (1993) determination of the average neutron star mass in 17 systems; 1.35 +/- 0.27 M(.). Variations in the exponent of a Salpeter initial mass function are shown not to affect the locations of the two peaks in the distribution function, but do affect their relative amplitudes. Sources of uncertainty, in particular placement of the mass cut and sensitivity to the explosion energy, are discussed, and estimates of the total number of neutron stars and black holes in the Galaxy are given. Accretion-induced collapse should give a unique gravitational mass of 1.27 M(.), although this could increase if accretion onto the newly formed star continues. A similar mass will typify stars in the 8-11 M(.) range (e.g., the Crab pulsar). The lightest neutron star produced is 1.15 M(.) for the Type II models and 1.22 M(.) for the Type Ib models. Altogether there are about 10(9) neutron stars in our Galaxy and a comparable number of black holes. C1 UNIV CALIF SANTA CRUZ,UNIV CALIF OBSERV,LICK OBSERV,BOARD STUDIES ASTRON & ASTROPHYS,SANTA CRUZ,CA 95064. LAWRENCE LIVERMORE NATL LAB,GEN STUDIES DIV,LIVERMORE,CA 94550. RP Timmes, FX (reprint author), UNIV CHICAGO,ENRICO FERMI INST,LAB ASTROPHYS & SPACE RES,5640 S ELLIS AVE,CHICAGO,IL 60637, USA. NR 92 TC 204 Z9 205 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1996 VL 457 IS 2 BP 834 EP 843 DI 10.1086/176778 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600034 ER PT J AU Link, B Epstein, RI AF Link, B Epstein, RI TI Thermally driven neutron star glitches SO ASTROPHYSICAL JOURNAL LA English DT Article DE dense matter; stars, evolution; stars, interiors; stars, neutron ID MAGNETIC-FIELD DECAY; DRIP SUPERFLUID; PULSAR GLITCHES; VORTEX CREEP; SPIN-UP; INTERNAL TEMPERATURE; TIMING OBSERVATIONS; MODEL ATMOSPHERES; CRUST SUPERFLUID; RESISTIVE FORCE AB We examine the thermal and dynamical response of a neutron star to a sudden perturbation of the inner crust temperature. During the star's evolution, starquakes and other processes may deposit greater than or similar to 10(42) ergs, causing significant internal heating and increased frictional coupling between the crust and the more rapidly rotating neutron superfluid the star is expected to contain. Through numerical simulation we study the propagation of the thermal wave created by the energy deposition, the induced motion of the interior superfluid, and the resulting spin evolution of the crust. We find that energy depositions of similar to 10(40) ergs produce gradual spin-ups above the timing noise level, while larger energy depositions produce sudden spin jumps resembling pulsar glitches. For a star with a temperature in the observed range of the Vela pulsar, an energy deposition of similar to 10(42) ergs produces a large spin-up taking place over minutes, similar to the Vela ''Christmas'' glitch. Comparable energy deposition in a younger and hotter ''Crab-like'' star produces a smaller spin-up taking place over similar to 1(d), similar to that seen during the partially time-resolved Crab glitch of 1989. C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Link, B (reprint author), MONTANA STATE UNIV,DEPT PHYS,BOZEMAN,MT 59717, USA. NR 60 TC 72 Z9 72 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 1996 VL 457 IS 2 BP 844 EP 854 DI 10.1086/176779 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600035 ER PT J AU Dykema, PG Klein, RI Castor, JI AF Dykema, PG Klein, RI Castor, JI TI A new scheme for multidimensional line transfer .3. A two-dimensional Lagrangian variable tensor method with discontinuous finite-element Sn transport SO ASTROPHYSICAL JOURNAL LA English DT Article DE line formation; methods, numerical; radiative transfer AB We describe a new code-ALTAIR-that has been developed to solve the time-dependent non-LTE problem for a multilevel atom in two-dimensional axisymmetric geometry on a Lagrangian mesh of arbitrary complexity. The method and results are presented here for a two-level atom. The extension to a multilevel atom is made by the equivalent two-level atom (ETLA) methods we have recently described in Paper II of this series. The source function of the line formed by the two-level atom is iterated to self-consistency with the radiation held, which is obtained from a system of coupled moment equations that employs an Eddington tensor closure using the double-splitting method described in Paper I of this series. The Eddington tensor itself is derived from a formal solution of the photon transport equation, which is based on a new discontinuous finite-element technique; the tensor moment system uses a continuous representation. The Eddington tensor is updated in an outer iteration loop, within which the double-splitting iteration is used to find the self-consistent source function for a given tenser. The resulting method shows very rapid convergence of the scattering iteration, even for optically thick regions with scattering albedo near unity. In addition, the spatial structure of the solution is rather insensitive to the shape of the spatial zones; the calculation of problems with zone aspect ratios of 1000 to 1 causes no difficulty. Application to several benchmark calculations, including radiative transfer in a nonorthogonal mesh, is discussed. We find that for two-dimensional problems of astrophysical interest, many angle rays are required to ensure an accurate solution. RP LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. NR 21 TC 18 Z9 18 U1 1 U2 1 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 FEB 1 PY 1996 VL 457 IS 2 BP 892 EP 921 DI 10.1086/176784 PN 1 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA TQ546 UT WOS:A1996TQ54600040 ER PT J AU Tung, CS Soumpasis, DM AF Tung, CS Soumpasis, DM TI Structural prediction of A- and B-DNA duplexes based on coordinates of the phosphorus atoms SO BIOPHYSICAL JOURNAL LA English DT Article ID SEQUENCE DEPENDENCE; HELIX STRUCTURE; A-DNA; X-RAY; DODECAMER; CURVATURE; DYNAMICS; COMPLEX; ANGLES; ENERGY AB The sequence-dependent structure of DNA double helices was studied extensively during the past 10 years. How the backbone structure correlates with the base structure in a duplex conformation is still an important yet open question. Using a set of reduced coordinates and a least-squares fitting procedure, we have developed a method to predict structures for B-DNA duplexes based on coordinates of the phosphorus atoms. This method can be used to predict all-atom structures for both bent and straight molecules. We estimated the accuracies of the predictions by studying a set of 10 oligonucleotides with their structures available from the Protein Data Bank. We used this method to construct a modeled structure for the bacteriophage lambda cro operator for which the phosphorus coordinates were known from 3.5-Angstrom, resolution crystal data (4CRO). C1 MAX PLANCK INST BIOPHYS CHEM, BIOCOMPUTAT GRP, W-3400 GOTTINGEN, GERMANY. RP LOS ALAMOS NATL LAB, DIV THEORET, MAIL STOP K-710, GRP T-10, LOS ALAMOS, NM 87545 USA. NR 37 TC 11 Z9 11 U1 0 U2 0 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0006-3495 EI 1542-0086 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP 917 EP 923 PG 7 WC Biophysics SC Biophysics GA TY684 UT WOS:A1996TY68400032 PM 8789108 ER PT J AU Wistrom, CA Jones, GM Tobias, PS Sklar, LA AF Wistrom, CA Jones, GM Tobias, PS Sklar, LA TI Fluorescence resonance energy transfer analysis of lipopolysaccharide in detergent micelles SO BIOPHYSICAL JOURNAL LA English DT Article ID FREE LIPID-A; POLYACRYLAMIDE-GEL-ELECTROPHORESIS; ROUGH MUTANT LIPOPOLYSACCHARIDE; SALMONELLA-MINNESOTA R595; BINDING-PROTEIN; ESCHERICHIA-COLI; BACTERIAL LIPOPOLYSACCHARIDE; SUPRAMOLECULAR STRUCTURE; ORIENTATIONAL FREEDOM; SODIUM DEOXYCHOLATE AB Bacterial endotoxins or lipopolysaccharides (LPS), cell wall components of gram-negative bacteria, are involved in septic shock. LPS consists of a lipid A tail attached to core and O-antigen polysaccharides, but little is known about the supramolecular structure of LPS in blood. We have developed an approach to locate donor and acceptor probes in sulfobetaine palmitate detergent micelles using steady-state and time-resolved fluorescence resonance energy transfer. C18-fluorescein and several LPS species of varying molecular weight labeled with fluorescein isothiocyanate (FITC-LPS) were the donor probes, Acceptor probes were 1,1-dilinoleyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (Fast C18-Dil, R(0) approximate to 68 Angstrom), and octadecyl B rhodamine chloride (C18-Rhd, R(0) approximate to 58 Angstrom). With either acceptor, the transfer was of similar high efficiency when FITC-LPS Salmonella minnesota Re 595 (2,500 mol wt, lacking both core and O-antigen) or C18-fluorescein were the fluorescent donor probes. Thus, the donor FITC-LPS with short polysaccharide chain S. minnesota Re 595 and the control donor C18-fluorescein appear to be close to the micelle surface. The transfer efficiency decreased as the molecular weight of the LPS increased. Separation distances between the longest FITC-LPS, S. minnesota (20,000 mol wt, with a long O-antigen), and the micelle were estimated to be 1.5 R(0) or more (similar to 100 Angstrom), consistent with an extended conformation for the longer O-antigen polysaccharide chain in the detergent. C1 UNIV NEW MEXICO, SCH MED, CTR CANC, DEPT CYTOMET, ALBUQUERQUE, NM 87131 USA. LOS ALAMOS NATL LAB, NATL FLOW CYTOMET RESOURCE, LOS ALAMOS, NM 87545 USA. LOS ALAMOS NATL LAB, DIV LIFE SCI, LOS ALAMOS, NM 87545 USA. Scripps Res Inst, DEPT IMMUNOL, LA JOLLA, CA 92037 USA. FU NCRR NIH HHS [RR01315]; NIGMS NIH HHS [GM37696] NR 56 TC 11 Z9 11 U1 0 U2 2 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP 988 EP 997 PG 10 WC Biophysics SC Biophysics GA TY684 UT WOS:A1996TY68400040 PM 8789116 ER PT J AU Tinoco, I Chen, X Hines, JV Kang, H Shen, LX AF Tinoco, I Chen, X Hines, JV Kang, H Shen, LX TI Frameshifts, retroviruses and pseudoknots SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP AWAR3 EP AWAR3 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200125 ER PT J AU Barsky, D Dong, Q Colvin, ME Melius, CF Ludeman, SM Colvin, OM Bigner, DD Modrich, P Friedman, HS AF Barsky, D Dong, Q Colvin, ME Melius, CF Ludeman, SM Colvin, OM Bigner, DD Modrich, P Friedman, HS TI A structural basis for a phosphoramide mustard-induced DNA interstrand cross-link at 5'd(GAC) SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 HOWARD HUGHES MED INST,DEPT PATHOL,DURHAM,NC 27710. HOWARD HUGHES MED INST,DEPT PEDIAT,DURHAM,NC 27710. DUKE UNIV,MED CTR,DEPT BIOCHEM,DURHAM,NC 27710. SANDIA NATL LABS,LIVERMORE,CA 94551. JOHNS HOPKINS UNIV,CTR ONCOL,BALTIMORE,MD 21287. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP447 EP MP447 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201330 ER PT J AU Dyer, RB Williams, S Woodruff, WH Gilmanshin, R Callender, RH AF Dyer, RB Williams, S Woodruff, WH Gilmanshin, R Callender, RH TI Fast events in protein folding: Helix dynamics in proteins and model peptides SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. CUNY CITY COLL,DEPT PHYS,NEW YORK,NY 10031. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP137 EP MP137 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201022 ER PT J AU Garcia, AE Hummer, G AF Garcia, AE Hummer, G TI Molecular dynamics simulation of equilibrium folding and unfolding transitions of proteins. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,THEORET BIOL & BIOPHYS GRP,LOS ALAMOS,NM 87545. RI Hummer, Gerhard/A-2546-2013 OI Hummer, Gerhard/0000-0001-7768-746X NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MPMC2 EP MPMC2 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200844 ER PT J AU Grad, R Shapiro, R Hingerty, BE Broyde, S AF Grad, R Shapiro, R Hingerty, BE Broyde, S TI Minor groove DNA conformations of the N-2 guanine adduct of 2-acetylaminofluorene (AAF): Differing orientations in different sequence contexts. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NYU,DEPT BIOL,NEW YORK,NY 10003. NYU,DEPT CHEM,NEW YORK,NY 10003. OAK RIDGE NATL LAB,HLTH SCI RES DIV,OAK RIDGE,TN 37831. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP449 EP MP449 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201331 ER PT J AU Hummer, G Garde, S Garcia, AE Pohorille, A Pratt, LR AF Hummer, G Garde, S Garcia, AE Pohorille, A Pratt, LR TI Hydrophobic interactions: A fluctuation model. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545. UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143. NASA,AMES RES CTR,MOFFETT FIELD,CA 94035. RI Pratt, Lawrence/H-7955-2012; Hummer, Gerhard/A-2546-2013 OI Pratt, Lawrence/0000-0003-2351-7451; Hummer, Gerhard/0000-0001-7768-746X NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP420 EP MP420 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201302 ER PT J AU Jentzen, W Song, X Shelnutt, JA AF Jentzen, W Song, X Shelnutt, JA TI Quantitative description of out-of-plane distortion of the macrocycle of synthetic and protein-bound porphyrins SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 SANDIA NATL LABS,FUEL SCI DEPT,ALBUQUERQUE,NM 87185. UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. RI Shelnutt, John/A-9987-2009 OI Shelnutt, John/0000-0001-7368-582X NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MPMG2 EP MPMG2 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200879 ER PT J AU Lee, JW Greenbaum, E AF Lee, JW Greenbaum, E TI Discovery of a new photosynthetic pathway: Photosystem II light reaction can support complete photosynthesis SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831. NR 0 TC 1 Z9 1 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MAMG1 EP MAMG1 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200747 ER PT J AU Miller, LM Scheuring, E Wang, H Peng, G Cramer, SP Chance, MR AF Miller, LM Scheuring, E Wang, H Peng, G Cramer, SP Chance, MR TI L-edge X-ray absorption spectroscopy of ligand-bound and photoproduct states of myoglobin. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 YESHIVA UNIV ALBERT EINSTEIN COLL MED,DEPT PHYSIOL & BIOPHYS,BRONX,NY 10461. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV ENERGY & ENVIRONM,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP381 EP MP381 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201264 ER PT J AU Rentzeperis, D Holder, J Marky, LA Garcia, AE AF Rentzeperis, D Holder, J Marky, LA Garcia, AE TI Thermodynamics of non-canonical base-pair and loop stacking interactions of centromere sequences SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 NYU,DEPT CHEM,NEW YORK,NY 10003. LOS ALAMOS NATL LAB,THEORET BIOL & BIOPHYS GRP,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MPO12 EP MPO12 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200897 ER PT J AU Roach, MP Franzen, S Pang, PSH Boxer, SG Woodruff, WH Dawson, JH AF Roach, MP Franzen, S Pang, PSH Boxer, SG Woodruff, WH Dawson, JH TI A hemeprotein model for the substrate-bound five-coordinate ferric cytochrome P-450(cam) active site SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV S CAROLINA,DEPT CHEM & BIOCHEM,COLUMBIA,SC 29208. LOS ALAMOS NATL LAB,BIOSCI & BIOTECHNOL GRP,LOS ALAMOS,NM 87545. STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. NR 3 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP352 EP MP352 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201235 ER PT J AU Sanchez, E Mets, L Xie, S AF Sanchez, E Mets, L Xie, S TI Near-field fluorescence microscopy and spectroscopy of photosynthetic membranes SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 PACIFIC NW LAB, ENVIRONM MOLEC SCI LAB, RICHLAND, WA 99352 USA. UNIV CHICAGO, DEPT MOLEC GENET & CELL BIOL, CHICAGO, IL 60637 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MAMG8 EP MAMG8 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200755 ER PT J AU Song, X Jentzen, W Jia, S Jaquinod, LA Nurco, DJ Medforth, GJ Smith, KM Shelnutt, JA AF Song, X Jentzen, W Jia, S Jaquinod, LA Nurco, DJ Medforth, GJ Smith, KM Shelnutt, JA TI Nonplanar distortions of nickel(II) dialkylporphyrins along combinations of the lowest-frequency out-of-plane normal coordinates SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 SANDIA NATL LABS,FUEL SCI DEPT,ALBUQUERQUE,NM 87185. UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. UNIV CALIF DAVIS,DEPT CHEM,DAVIS,CA 95616. RI Shelnutt, John/A-9987-2009; Smith, Kevin/G-1453-2011 OI Shelnutt, John/0000-0001-7368-582X; Smith, Kevin/0000-0002-6736-4779 NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MPMG4 EP MPMG4 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200880 ER PT J AU Sutherland, JC Reynolds, K AF Sutherland, JC Reynolds, K TI Empirical dispersion functions for separations of DNA by static field gel electrophoresis. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MPO28 EP MPO28 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200911 ER PT J AU vonGustedt, W Chan, M Nikaido, H Jap, BK AF vonGustedt, W Chan, M Nikaido, H Jap, BK TI Large-scale purification of an ABC-type protein complex, the maltose transporter of E-coli and preliminary crystallization results. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MP292 EP MP292 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201175 ER PT J AU Wolf, SG Nogales, E Goode, BL Feinstein, SC Downing, KH AF Wolf, SG Nogales, E Goode, BL Feinstein, SC Downing, KH TI Visualization of tau binding to tubulin zinc sheets by electron crystallography SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LAWRENCE BERKELEY NATL LAB,DIV LIFE SCI,BERKELEY,CA 94720. UNIV CALIF SANTA BARBARA,NEUROSCI RES INST,SANTA BARBARA,CA 93106. NR 3 TC 0 Z9 0 U1 1 U2 2 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP MAMC6 EP MAMC6 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200721 ER PT J AU Chasis, JA Knowles, DW Gimm, JA Lee, G McGee, S Anstee, D Mohandas, N AF Chasis, JA Knowles, DW Gimm, JA Lee, G McGee, S Anstee, D Mohandas, N TI Band 3 regulates membrane rigidity by two distinct mechanisms SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA 94720. SW REG BLOOD TRANSFUS CTR,BRISTOL,AVON,ENGLAND. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU387 EP SU387 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200571 ER PT J AU Chen, X Mariappan, SVS Ratliff, R Moyzis, RK Smith, SS Bradbury, EM Gupta, G AF Chen, X Mariappan, SVS Ratliff, R Moyzis, RK Smith, SS Bradbury, EM Gupta, G TI The formation and methylation of the ''slippage structures'' in vitro: The molecular basis of the fragile-X syndrome SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. LOS ALAMOS NATL LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. CITY HOPE NATL MED CTR,DEPT CELL & TUMOR BIOL,DUARTE,CA 91010. NR 0 TC 0 Z9 0 U1 1 U2 2 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU496 EP SU496 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200680 ER PT J AU Huang, K Flanagan, JM Prestegard, JH AF Huang, K Flanagan, JM Prestegard, JH TI Structural studies by NMR of the N-terminal domains of the chaperone protein DnaJ SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 YALE UNIV,NEW HAVEN,CT 06511. BROOKHAVEN NATL LAB,UPTON,NY 11973. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU390 EP SU390 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200575 ER PT J AU Knowles, DW Gimm, JA Tilley, L Mohandas, N Chasis, JA AF Knowles, DW Gimm, JA Tilley, L Mohandas, N Chasis, JA TI Increased cytoskeletal interaction of glycophorin A and band 3 induced by glycophorin A receptor ligands SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,BERKELEY,CA. LA TROBE UNIV,DEPT BIOCHEM,BUNDOORA,VIC 3083,AUSTRALIA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU386 EP SU386 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200573 ER PT J AU Krueger, JK Gu, W Olah, GA Bishop, N Trewhella, J AF Krueger, JK Gu, W Olah, GA Bishop, N Trewhella, J TI Small-angle scattering and modeling studies of myosin light chain kinase with and without Ca2+center dot calmodulin SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. UNIV TEXAS,SW MED CTR,DEPT PHYSIOL,DALLAS,TX 75235. RI Krueger, Joanna/A-3110-2011 NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUP92 EP SUP92 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200279 ER PT J AU Leone, M Unger, E Jentzen, W Cupane, A Cordone, L Gilch, H Dreybrodt, W SchweitzerStenner, R AF Leone, M Unger, E Jentzen, W Cupane, A Cordone, L Gilch, H Dreybrodt, W SchweitzerStenner, R TI Structural heterogeneity of Ni(II)-octaethylporphyrin in organic liquids and glasses. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV PALERMO,INST FIS,I-90123 PALERMO,ITALY. UNIV BREMEN,INST EXPTL PHYS,D-28359 BREMEN,GERMANY. SANDIA NATL LABS,FUEL SCI DEPT,ALBUQUERQUE,NM 87185. RI Leone, Maurizio/F-2353-2010 OI Leone, Maurizio/0000-0002-0292-7657 NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUAM7 EP SUAM7 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200121 ER PT J AU Mariappan, SVS Chen, X Silks, LA Ratliff, R Moyzis, RK Bradbury, EM Garcia, AE Gupta, G AF Mariappan, SVS Chen, X Silks, LA Ratliff, R Moyzis, RK Bradbury, EM Garcia, AE Gupta, G TI Unusual structures formed by CAG DNA triplets SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 1 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUPM7 EP SUPM7 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200149 ER PT J AU Mendelson, RA Schneider, DK Stone, DB AF Mendelson, RA Schneider, DK Stone, DB TI Conformations of myosin subfragment-one ATPase intermediates from small-angle scattering SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF SAN FRANCISCO,CVRI,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,DEPT BIOCHEM & BIOPHYS,SAN FRANCISCO,CA 94143. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUAM1 EP SUAM1 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200013 ER PT J AU Miksovska, J Hanson, DK Schiffer, M Sebban, P AF Miksovska, J Hanson, DK Schiffer, M Sebban, P TI Study of revertants from the L212Glu->Gln photo-incompetent reaction center mutant from Rhodobacter capsulatus SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 CNRS,CTR GENET MOLEC,F-91198 GIF SUR YVETTE,FRANCE. ARGONNE NATL LAB,CMB,ARGONNE,IL. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUAM1 EP SUAM1 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200054 ER PT J AU Raffen, R Stevens, PW Hanson, DK Deng, Y BerriosHammond, M Westholm, FA Schiffer, M Stevens, FJ AF Raffen, R Stevens, PW Hanson, DK Deng, Y BerriosHammond, M Westholm, FA Schiffer, M Stevens, FJ TI In vitro characterization of light chain amyloidosis using recombinant light chain variable domains. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU190 EP SU190 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200373 ER PT J AU Sauer, K AF Sauer, K TI Modeling excitation transfer dynamics in antenna complexes of known structure. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV STRUCT BIOL,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUPM4 EP SUPM4 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200129 ER PT J AU Seeger, PA Rokop, SE Palmer, PD Henderson, SJ Hobart, DE Trewhella, J AF Seeger, PA Rokop, SE Palmer, PD Henderson, SJ Hobart, DE Trewhella, J TI Neutron resonance scattering from Pu-240(3+) bound to the Ca2+-binding sites in calmodulin: A new structural probe. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUAM9 EP SUAM9 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200092 ER PT J AU Shelnutt, JA AF Shelnutt, JA TI Possible functional roles of non-planar conformers of tetrapyrroles in proteins. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. SANDIA NATL LABS,FUEL SCI DEPT,ALBUQUERQUE,NM 87185. RI Shelnutt, John/A-9987-2009 OI Shelnutt, John/0000-0001-7368-582X NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUAM8 EP SUAM8 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200124 ER PT J AU Thorgeirsson, TE Russell, CJ Shin, YK AF Thorgeirsson, TE Russell, CJ Shin, YK TI Direct determination of the membrane affinities of individual amino acids in a polypeptide: A host-guest study. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU344 EP SU344 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200529 ER PT J AU Tiede, DM Vazquez, J Cordova, J Marone, PA AF Tiede, DM Vazquez, J Cordova, J Marone, PA TI Time-resolved electrochromism associated with the formation of quinone anions in Rhodobacter sphaeroides R-26 reaction centers SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUAM3 EP SUAM3 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200055 ER PT J AU Tung, CS Soumpasis, DM AF Tung, CS Soumpasis, DM TI Structural prediction of B-DNA duplexes based on coordinates of the phosphorus atoms. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. MAX PLANCK INST BIOPHYS CHEM,BIOCOMPUTAT GRP,W-3400 GOTTINGEN,GERMANY. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SUPM3 EP SUPM3 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200178 ER PT J AU Vonck, J AF Vonck, J TI A helix tilt in the N-intermediate of the bacteriorhodopsin photocycle SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY NATL LAB,DIV LIFE SCI,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU438 EP SU438 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200622 ER PT J AU Watkins, JA Lorio, JJ Donohoe, RJ Mecklenberg, SL Li, CY Besser, EJ Rimmer, DM Glass, J AF Watkins, JA Lorio, JJ Donohoe, RJ Mecklenberg, SL Li, CY Besser, EJ Rimmer, DM Glass, J TI Non-transferrin iron(III) binding sites on the interior surface of endosomes SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOUISIANA STATE UNIV,MED CTR,CTR EXCELLENCE CANC RES TREATMENT & EDUC,SHREVEPORT,LA 71130. LOS ALAMOS NATL LAB,DIV CHEM SCI & TECHNOL,LOS ALAMOS,NM 87544. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP SU406 EP SU406 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68200589 ER PT J AU Fan, B Larsen, RW Simpson, C Niu, S Falcon, R Marteniz, L Fontenot, DL Ondrias, M AF Fan, B Larsen, RW Simpson, C Niu, S Falcon, R Marteniz, L Fontenot, DL Ondrias, M TI Characterization and electron transfer studies on a coordination complex between microperoxidase-11 and ruthenium trisbipyridine derivatised bifunctional peptides SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. UNIV HAWAII MANOA,DEPT CHEM,HONOLULU,HI 96822. SANDIA NATL LABS,FUEL SCI DIV,LIVERMORE,CA 94550. LOS ALAMOS NATL LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP TU470 EP TU470 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201991 ER PT J AU Franzen, S Decatur, SM Boxer, SG Dyer, RB Woodruff, WH AF Franzen, S Decatur, SM Boxer, SG Dyer, RB Woodruff, WH TI A hemeprotein model for the ligand switch in cytochrome c oxidase SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,BIOSCI & BIOTECHNOL GRP,LOS ALAMOS,NM 87545. STANFORD UNIV,DEPT CHEM,STANFORD,CA 94305. NR 3 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP TUAM1 EP TUAM1 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201453 ER PT J AU Gao, F Qin, H Knaff, DB Simpson, MC Shelnutt, JA Ondrias, MR AF Gao, F Qin, H Knaff, DB Simpson, MC Shelnutt, JA Ondrias, MR TI Resonance Raman studies of inhibitors and inhibitor solvents effect on Rhodobacter capsulatus bc(1) complexes SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV NEW MEXICO,DEPT CHEM,ALBUQUERQUE,NM 87131. TEXAS TECH UNIV,DEPT CHEM & BIOCHEM,LUBBOCK,TX 79409. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RI Shelnutt, John/A-9987-2009; Simpson, Miriam/C-4237-2011 OI Shelnutt, John/0000-0001-7368-582X; NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP TU469 EP TU469 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201988 ER PT J AU Kelly, LA Sutherland, JC AF Kelly, LA Sutherland, JC TI Low temperature electronic spectroscopy of adenine derivatives SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11973. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP TUPM6 EP TUPM6 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68201511 ER PT J AU Cerritelli, ME Cheng, N Rosenberg, AH Simon, MN Steven, AC AF Cerritelli, ME Cheng, N Rosenberg, AH Simon, MN Steven, AC TI Organization of dsDNA in bacteriophage T7 capsids: Support for the coaxial-spool model SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract ID HEADS C1 NIAMS,NIH,LSB,BETHESDA,MD 20892. BROOKHAVEN NATL LAB,UPTON,NY 11973. NR 3 TC 0 Z9 0 U1 1 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WAMC1 EP WAMC1 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202100 ER PT J AU Hernandez, G Rokop, SE Springer, PA Unkefer, CJ Trewhella, J AF Hernandez, G Rokop, SE Springer, PA Unkefer, CJ Trewhella, J TI NMR studies of troponin I(96-115): Free in solution and bound to troponin C. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WPO31 EP WPO31 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202218 ER PT J AU Mannuzzu, LM Moronne, MM Isacoff, EY AF Mannuzzu, LM Moronne, MM Isacoff, EY TI S4 movement correlates with gating charge displacement during shaker channel gating. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WP161 EP WP161 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202350 ER PT J AU Mitchell, RD Olah, GA Gu, W Corbin, J Francis, SH Walsh, DA Trewhella, J AF Mitchell, RD Olah, GA Gu, W Corbin, J Francis, SH Walsh, DA Trewhella, J TI The solution structure of cGMP-dependent protein kinase (PKG) and its alteration upon activation by cGMP. SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF DAVIS,DEPT BIOL CHEM,DAVIS,CA 95616. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. VANDERBILT UNIV,DEPT MOLEC PHYSIOL & BIOPHYS,NASHVILLE,TN 37232. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WP313 EP WP313 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202501 ER PT J AU Pertsemlidis, A Saxena, AM Soper, AK HeadGordon, T Glaeser, RM AF Pertsemlidis, A Saxena, AM Soper, AK HeadGordon, T Glaeser, RM TI Perturbation of water structure by amino acid side chains SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. BROOKHAVEN NATL LAB,UPTON,NY 11973. RUTHERFORD APPLETON LAB,DIDCOT,OXON,ENGLAND. LAWRENCE BERKELEY LAB,BERKELEY,CA. RI Head-Gordon, Teresa/E-5818-2011 NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WP369 EP WP369 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202555 ER PT J AU Selvin, PR Ha, T Enderle, T Ogletree, DF Chemla, DS Weiss, S AF Selvin, PR Ha, T Enderle, T Ogletree, DF Chemla, DS Weiss, S TI Fluorescence resonance energy transfer between a single donor and a single acceptor molecule SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA. LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA. RI weiss, shimon/B-4164-2009 OI weiss, shimon/0000-0002-0720-5426 NR 0 TC 1 Z9 1 U1 0 U2 2 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WP302 EP WP302 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202487 ER PT J AU Shapiro, DB Esquerra, RM Goldbeck, RA Ballas, SK Mohandas, N Kliger, DS AF Shapiro, DB Esquerra, RM Goldbeck, RA Ballas, SK Mohandas, N Kliger, DS TI Religation kinetics of sickle cell hemoglobin polymer SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF SANTA CRUZ,DEPT CHEM & BIOCHEM,SANTA CRUZ,CA 95064. THOMAS JEFFERSON UNIV,JEFFERSON MED COLL,DEPT MED,CALDEZA FDN,PHILADELPHIA,PA 19107. LAWRENCE BERKELEY LAB,DIV LIFE SCI,BERKELEY,CA 94720. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WP327 EP WP327 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202514 ER PT J AU Weiss, S Ha, T Enderle, T Chemla, DS Selvin, PR AF Weiss, S Ha, T Enderle, T Chemla, DS Selvin, PR TI Super-resolution distance measurements by nonresonant dual-color imaging of single molecules SO BIOPHYSICAL JOURNAL LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,INST MOLEC DESIGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RI weiss, shimon/B-4164-2009 OI weiss, shimon/0000-0002-0720-5426 NR 0 TC 0 Z9 0 U1 0 U2 1 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1996 VL 70 IS 2 BP WP301 EP WP301 PN 2 PG 1 WC Biophysics SC Biophysics GA TZ682 UT WOS:A1996TZ68202489 ER PT J AU Kuypers, FA Lewis, RA Hua, M Schott, MA Discher, D Ernst, JD Lubin, BH AF Kuypers, FA Lewis, RA Hua, M Schott, MA Discher, D Ernst, JD Lubin, BH TI Detection of altered membrane phospholipid asymmetry in subpopulations of human red blood cells using fluorescently labeled annexin V SO BLOOD LA English DT Article ID HUMAN-ERYTHROCYTES; LIPID ASYMMETRY; TRANSBILAYER DISTRIBUTION; BIOLOGICAL-MEMBRANES; VESICLE AGGREGATION; PHOSPHATIDYLSERINE; MOBILITY; PHOSPHATIDYLINOSITOL; TRANSLOCATION; VESICULATION AB The phospholipids of the human red cell are distributed asymmetrically ire the bilayer of the red cell membrane, In certain pathologic states, such as sickle cell anemia, phospholipid asymmetry is altered. Although several methods can be used to measure phospholipid organization, small organizational changes have been very difficult to assess. Moreover, these methods fail to identify subpopulations of cells that have lost their normal phospholipid asymmetry. Using fluorescently labeled annexin V in flow cytometry and fluorescent microscopy, we were able to identify and quantify red cells that had lost their phospholipid asymmetry in populations as small as 1 million cells. Moreover, loss of phospholipid organization in subpopulations as small as 0.1% of the total population could be identified, and individual cells could be studied by fluorescent microscopy. An excellent correlation was found between fluorescence-activated cell sorter (FAGS) analysis results using annexin V to detect red cells with phosphatidylserine (PS) on their surface and a PS-requiring prothrombinase assay using similar red cells. Cells that bound fluorescein isothiocyanate (FITC)-labeled annexin V could be isolated from the population using magnetic beads covered with an anti-FITC antibody, Evaluation of blood samples from patients with sickle cell anemia under oxygenated conditions demonstrated the presence of subpopulations of cells that had lost phospholipid asymmetry, While only a few red cells were labeled in normal control samples (0.21% +/- 0.12%, n = 8), significantly increased (P < .001) annexin V labeling was observed in samples from patients with sickle cell anemia (2.18% +/- 1.21%, n = 13). We conclude that loss of phospholipid asymmetry may occur in small subpopulations of red cells and that fluorescently labeled annexin V can be used to quantify and isolate these cells. (C) 1996 by The American Society of Hematology. C1 UNIV CALIF SAN FRANCISCO,SAN FRANCISCO GEN HOSP,SAN FRANCISCO,CA. LAWRENCE BERKELEY LAB,BERKELEY,CA. RP Kuypers, FA (reprint author), CHILDRENS HOSP,OAKLAND RES INST,747 52ND ST,OAKLAND,CA 94609, USA. FU NHLBI NIH HHS [HL20985, HL55213]; NIDDK NIH HHS [DK32094] NR 33 TC 223 Z9 225 U1 2 U2 4 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 SN 0006-4971 J9 BLOOD JI Blood PD FEB 1 PY 1996 VL 87 IS 3 BP 1179 EP 1187 PG 9 WC Hematology SC Hematology GA TT484 UT WOS:A1996TT48400043 PM 8562945 ER PT J AU Protti, M Schwartz, SY Zandt, G AF Protti, M Schwartz, SY Zandt, G TI Simultaneous inversion for earthquake location and velocity structure beneath central Costa Rica SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID CRUSTAL STRUCTURE; CENTRAL AMERICA; P-WAVE; CALIFORNIA; HYPOCENTERS; TOMOGRAPHY AB We have imaged the complex crustal and upper mantle structure beneath central Costa Rica using P-wave arrival times from locally recorded earthquakes. Thurber's (1983) iterative inversion method is used to simultaneously estimate velocities along a three-dimensional grid and hypocentral parameters of local earthquakes. Our data consist of over 12,000 arrival times from more than 1300 earthquakes recorded by stations of a permanent seismographic network in Costa Rica. Our resulting velocity model correlates well with mapped geologic units at very shallow depth and with tectonic features at greater depth. We find low velocities (4.0 to 4.8 km/sec) in the shallow crust (above 10 km) near the active volcanoes and associated with a NW-SE trending late Cretaceous to late Tertiary sedimentary basin southeast of Herradura peninsula. High velocities (5.4 to 5.7 km/sec) in the shallow crust correlate with outcrops of late Jurassic to early Tertiary ultramafic ophiolitic units and with basic Tertiary volcanic units. At depths between 20 and 30 km, high velocities (6.8 to 7.2 km/sec) are associated with the subducting Cocos plate under Costa Rica and two prominent low-velocity bodies (6.3 to 6.5 km/sec) are present about 30 km trenchward of the volcanic are and along the projection of the aseismic Cocos Ridge as it subducts beneath Costa Rica. The thickened oceanic crust of the Cocos Ridge is most likely responsible for its low velocities. The deep low-velocity anomaly located trenchward of the axis of the volcanoes may indicate the presence of a low-density intrusive resulting from an earlier phase of magmatism, possibly the late Miocene episode that produced the Talamanca intrusive complex. C1 UNIV CALIF SANTA CRUZ,DEPT EARTH SCI,SANTA CRUZ,CA 95064. UNIV CALIF SANTA CRUZ,INST TECTON,SANTA CRUZ,CA 95064. LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. RP Protti, M (reprint author), COSTA RICA UNIV NACL,OBSERV VULCANOL & SISMOL,HEREDIA,COSTA RICA. OI Protti, Marino/0000-0001-9818-0051 NR 30 TC 17 Z9 18 U1 0 U2 2 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD FEB PY 1996 VL 86 IS 1 BP 19 EP 31 PN A PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TZ064 UT WOS:A1996TZ06400002 ER PT J AU Searcy, CK Christensen, DH Zandt, G AF Searcy, CK Christensen, DH Zandt, G TI Velocity structure beneath College Station Alaska from receiver functions SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID YUKON-TANANA TERRANE; EAST-CENTRAL ALASKA; TECTONIC SIGNIFICANCE; RANGE AB Time-domain inversions of radial receiver functions and forward modeling of radial and tangential receiver functions were used to determine the velocity structure beneath DWWSSN station COL (Fairbanks, Alaska), Intermediate-period waveforms from 57 events recorded between February 1982 and November 1985 were used in the final analysis. Receiver functions from similar backazimuths and distances are very uniform and were stacked to increase the signal-to-noise ratio, At some azimuths (particularly from the west), significant energy is observed in the tangential component, indicating the existence of heterogeneous structure. The calculated velocity profiles are complicated and contain several distinct features that are consistent between the different stacks. The most obvious features are two strong velocity increases or boundaries in the lower crust. The first of these velocity gradients is between 27 and 32 km, a depth that is often associated with the crust-mantle transition in this region. Forward modeling of the receiver function arrivals associated with this boundary indicates that it has a strike of similar to 280 degrees and a dip of at least 10 degrees to the northeast, The velocity profiles and forward modeling also indicate a low-velocity layer between depths of about 15 and 28 km. This layer is consistent with TACT results that show a layer at approximately this depth, with high electrical conductivity and a lower-than-expected seismic velocity, interpreted to be Mesozoic flysch. C1 LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. RP Searcy, CK (reprint author), UNIV ALASKA FAIRBANKS,INST GEOPHYS,903 KOYUKUK DR,FAIRBANKS,AK 99775, USA. NR 27 TC 11 Z9 12 U1 1 U2 3 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD FEB PY 1996 VL 86 IS 1 BP 232 EP 241 PN A PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TZ064 UT WOS:A1996TZ06400021 ER PT J AU Hutchings, L Jarpe, S AF Hutchings, L Jarpe, S TI Ground-motion variability at the highway 14 and I-5 interchange in the northern San Fernando Valley SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID EARTHQUAKE AB The purpose of this article is to analyze possible causes for failure of the structures at the Highway 14 and I-5 interchange in the northern San Fernando Valley following the magnitude M 6.7 San Fernando earthquake on 9 February 1971 and the M 6.7 Northridge earthquake on 17 January 1994. This interchange consisted of a series of structures up to 600-m long; during the 1971 and 1994 earthquakes, several of these structures separated along expansion joints and collapsed. To analyze the possible causes of failure, we recorded aftershocks at and near the interchange for 2 weeks following the 1994 earthquake. The aftershock recordings reveal a substantial relative spectral amplification (in the 1- to 10-Hz range) of a factor of 3 to 6 for sites located at the interchange (which is situated on sandstone) relative to a nearby rock (gneiss) outcrop site. Sites within the interchange area have a variation in amplification of a factor of 2 to 4 in the 1- to 10-Hz range. Also, substantial secondary arrivals were generated at two locations in the interchange area. We attribute variations in ground motion at the interchange to be due to variations in the composition of the sandstone and to topographic effects. We computed the linear-response strong ground motion for three sites at the interchange from the 1971 and 1994 main events using aftershock recordings of the Northridge earthquake from three sites (the south and north abutments of the southbound connector of Hwy 14 to I-5 and a central location to the interchange) as empirical Green's functions. The same source events are used for all three sites for a particular synthesis so that differences between synthesized strong ground motion are due to differences in location, geology, and topography of the three sites. Source rupture models are obtained from independent studies. We estimate (1) peak acceleration to have been near 1 g for both earthquakes, due to the topographic and geologic conditions and the geometry of the fault rupture; (2) differential displacement across the north and south extremes of the area from the Northridge earthquake to have been about 70 cm longitudinal and 40 cm transverse to the Hwy 14 to I-5 connector; (3) differential displacement across the north and south extremes of the area from the San Fernando earthquake to have been about 25 cm longitudinal and 20 cm transverse; and (4) relative motion to be fairly incoherent for frequencies above 0.5 Hz. These observations are attributed to local geologic and topographic conditions and to wave passage effects and could have contributed to collapse of structures during these earthquakes. RP Hutchings, L (reprint author), LAWRENCE LIVERMORE NATL LAB,DIV EARTH SCI,GEOL AMOSPHER HAZARDS PROJECT,POB 808,LIVERMORE,CA 94551, USA. NR 28 TC 7 Z9 7 U1 0 U2 0 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD FEB PY 1996 VL 86 IS 1 SU S BP S289 EP S299 PN B PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TZ652 UT WOS:A1996TZ65200021 ER PT J AU Snodgrass, JW Bryan, AL Lide, RF Smith, GM AF Snodgrass, JW Bryan, AL Lide, RF Smith, GM TI Factors affecting the occurrence and structure of fish assemblages in isolated wetlands of the upper coastal plain, USA SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID COMMUNITY STRUCTURE; SPECIES-DIVERSITY; PATTERNS; COMPETITION; LAKES AB To test a model of fish assemblage structure in isolated wetlands of the Atlantic Coastal Plain, we related the presence or absence of fishes in individual wetlands and variation in assemblage structure to environmental conditions within wetlands and to location in relation to permanent aquatic habitats. Fishes were limited to wetlands that dried infrequently, were relatively close to intermittent aquatic habitats, and had little elevation difference between the wetland and its nearest permanent aquatic habitat. Comparison of variation in assemblage structure among wetlands to null hypotheses of randomness suggested that biological interactions played a minor role in structuring these assemblages. We found no correlation between assemblage structure and wetland environment. Variation in assemblage structure was correlated with the geographic position of wetlands. Wetlands located in the upper portions of drainage basins were dominated by Lepomis marginatus and Erimyzon sucetta while wetlands located in downstream portions of drainage basins were dominated by Acantharchus pomotis and Gambusia holbrooki. Our results are consistent with a model of fish assemblage structure in which wetland drying frequency and connectivity determine the presence or absence of fishes, and differences in colonizing rates and the relative abundance of species in source pools influence variation among wetlands with fishes. RP Snodgrass, JW (reprint author), UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29802, USA. RI Snodgrass, Joel/C-5288-2016 NR 34 TC 78 Z9 82 U1 2 U2 16 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD FEB PY 1996 VL 53 IS 2 BP 443 EP 454 DI 10.1139/cjfas-53-2-443 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA UK632 UT WOS:A1996UK63200023 ER PT J AU Wessels, BW Breitz, H Mills, G Siegel, J Stabin, M Wessels, BW AF Wessels, BW Breitz, H Mills, G Siegel, J Stabin, M Wessels, BW TI The 10th international conference on monoclonal antibody immunoconjugates for cancer: Radiodosimetry and radiopharmaceuticals for therapy SO CANCER BIOTHERAPY AND RADIOPHARMACEUTICALS LA English DT Editorial Material C1 VIRGINIA MASON MED CTR,DEPT NUCL MED,SEATTLE,WA 98101. US FDA,DIV CLIN TRIALS DESIGN & ANAL,ROCKVILLE,MD 20857. UNIV MED & DENT NEW JERSEY,COOPER HOSP,MED CTR,DEPT RADIAT ONCOL,CAMDEN,NJ 08103. OAK RIDGE ASSOCIATED UNIV,RADIAT INTERNAL DOSE INFORMAT CTR,OAK RIDGE,TN. RP Wessels, BW (reprint author), GEORGE WASHINGTON UNIV,MED CTR,DIV RADIAT ONCOL & BIOPHYS,WASHINGTON,DC 20037, USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 1084-9785 J9 CANCER BIOTHER RADIO JI Cancer Biother. Radiopharm. PD FEB PY 1996 VL 11 IS 1 BP 25 EP 42 DI 10.1089/cbr.1996.11.25 PG 18 WC Oncology; Medicine, Research & Experimental; Pharmacology & Pharmacy; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Research & Experimental Medicine; Pharmacology & Pharmacy; Radiology, Nuclear Medicine & Medical Imaging GA UR855 UT WOS:A1996UR85500005 ER PT J AU Srivastava, SC AF Srivastava, SC TI Criteria for the selection of radionuclides for targeting nuclear antigens for cancer radioimmunotherapy SO CANCER BIOTHERAPY AND RADIOPHARMACEUTICALS LA English DT Article ID MONOCLONAL-ANTIBODIES; COMPLEXES; ACID AB The potential of utilizing immunoconjugates to selectively deliver radionuclides for the destruction of tumors has stimulated much research activity. From dosimetric and other considerations, the choice of radiolabeled is an important factor that needs to be optimized for maximum effectiveness of radioimmunotherapy (RIT). This paper reviews and assesses a number of present and future radionuclides that are particularly suitable for RIT based on the various physical, chemical, and biological considerations. Although intermediate to high-energy beta emitters (with and without gamma photons in their emission) possess a number of advantages for most RIT, the use of alpha, Auger, and short range conversion electron emitters could be attractive for targeting nuclear antigens when the radioimmunoconjugate is internalized into tumor cells. Factors relating to the production and availability of candidate radionuclides as well as their stable chemical attachment to monoclonal antibodies are discussed. RP Srivastava, SC (reprint author), BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973, USA. NR 47 TC 20 Z9 21 U1 0 U2 2 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 1084-9785 J9 CANCER BIOTHER RADIO JI Cancer Biother. Radiopharm. PD FEB PY 1996 VL 11 IS 1 BP 43 EP 50 DI 10.1089/cbr.1996.11.43 PG 8 WC Oncology; Medicine, Research & Experimental; Pharmacology & Pharmacy; Radiology, Nuclear Medicine & Medical Imaging SC Oncology; Research & Experimental Medicine; Pharmacology & Pharmacy; Radiology, Nuclear Medicine & Medical Imaging GA UR855 UT WOS:A1996UR85500006 PM 10851519 ER PT J AU Charych, D Cheng, Q Reichert, A Kuziemko, G Stroh, M Nagy, JO Spevak, W Stevens, RC AF Charych, D Cheng, Q Reichert, A Kuziemko, G Stroh, M Nagy, JO Spevak, W Stevens, RC TI A 'litmus test' for molecular recognition using artificial membranes SO CHEMISTRY & BIOLOGY LA English DT Article DE biosensor; Langmuir-Blodgett; liposome; polydiacetylene; self-assembly ID THERMOCHROMIC PHASE-TRANSITION; SUBSTITUTED POLYDIACETYLENES; OPTICAL-PROPERTIES; ACID MONOLAYERS; INFLUENZA-VIRUS; FILMS; POLYMERIZATION AB Background: Sensitive and selective molecular recognition is important throughout biology. Certain organisms and toxins use specific binding at the cell surface as a first step towards invasion. A new series of biomolecular materials, with novel optical and interfacial properties, have been designed to sense molecular recognition events. These polymers, the diacetylenic lipids, have previously been shown to undergo chromatic transitions in response to virus binding to the surface of the material. Results: Gangliosides that specifically bind cholera toxin, heat-labile Escherichia coli enterotoxin and botulinum neurotoxin were incorporated into a matrix oi diacetylenic lipids, 5-10% of which were derivatized with sialic acid. The lipids were self-assembled into Langmuir-Blodgett layers and polymerized with ultraviolet irradiation, yielding a polydiacetylene membrane with a characteristic blue color into which the ganglioside is non-covalently incorporated. When toxin is added, the polymerized membrane turns red. The response is specific and selective, and can be quantified by visible absorption spectrophotometry. Conclusions: Polydiacetylenic Lipid membranes offer a general 'litmus test' for molecular recognition at the surface of a membrane. A concentration of 20 ppm of protein could be detected using polymerized thin films. The speed, sensitivity and simplicity of the design offers a new and general approach towards the direct colorimetric detection of a variety of different molecules. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP Charych, D (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Cheng, Jason/C-6345-2011; Stevens, Raymond/K-7272-2015 OI Stevens, Raymond/0000-0002-4522-8725 NR 28 TC 198 Z9 201 U1 5 U2 28 PU CURRENT BIOLOGY LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 1074-5521 J9 CHEM BIOL JI Chem. Biol. PD FEB PY 1996 VL 3 IS 2 BP 113 EP 120 DI 10.1016/S1074-5521(96)90287-2 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA UB852 UT WOS:A1996UB85200006 PM 8807836 ER PT J AU Scott, B Bracewell, BL Johnson, SR Swanson, BI Bardeau, JF Bulou, A Hennion, B AF Scott, B Bracewell, BL Johnson, SR Swanson, BI Bardeau, JF Bulou, A Hennion, B TI Synthesis and characterization of a new polymorph of PtI containing an ordered MX chain SO CHEMISTRY OF MATERIALS LA English DT Article ID X = CL; TEMPERATURE; CRYSTAL; PD AB The structure described is a new polymorph of the one-dimensional material [Pt(en)(2)I-2] [Pt(en)(2)]-ClO4 (en = 1,2-diaminoethane) that occurs when the en ligands are fully deuterated. This structure is novel in that it contains ordered MX chains, a structural feature absent in all MX structures to date. It also represents a rare case of a structural change induced by isotopic substitution. This system presents a unique opportunity to study the interchain interactions that might lead to a fully ordered MX system and the behavior of ordered versus disordered chain systems. C1 UNIV MAINE,LAB PEC,F-72017 LE MANS,FRANCE. CENS,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE. RP Scott, B (reprint author), LOS ALAMOS NATL LAB,SPECT & BIOCHEM GRP CST 14,POB 1663,LOS ALAMOS,NM 87545, USA. RI Scott, Brian/D-8995-2017 OI Scott, Brian/0000-0003-0468-5396 NR 16 TC 11 Z9 11 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD FEB PY 1996 VL 8 IS 2 BP 321 EP & DI 10.1021/cm9503893 PG 0 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TW405 UT WOS:A1996TW40500005 ER PT J AU Eylem, C Hung, YC Ju, HL Kim, JY Green, DC Vogt, T Hriljac, JA Eichhorn, BW Greene, RL SalamancaRiba, L AF Eylem, C Hung, YC Ju, HL Kim, JY Green, DC Vogt, T Hriljac, JA Eichhorn, BW Greene, RL SalamancaRiba, L TI Unusual metal-insulator transitions in the LaTi1-xVxO3 perovskite phases SO CHEMISTRY OF MATERIALS LA English DT Article ID MAGNETIC-PROPERTIES; TRANSPORT-PROPERTIES; POWDER DIFFRACTION; SOLID-SOLUTIONS; SYSTEM; SEMICONDUCTOR; OXIDES; LATIO3; LAVO3; ND AB A series of LaTi1-xVxO3 compounds (0 less than or equal to x less than or equal to 1) have been prepared by the de are-melting method and characterized by conventional powder X-ray diffraction, thermogravimetric analysis, four-probe resistivity, and magnetic susceptibility studies. Selected members of this series have been characterized by synchrotron X-ray diffraction, neutron diffraction, selected area electron diffraction. Samples in the 0.2 less than or equal to x less than or equal to 0.3 region are similar to 3-4% La deficient (e.g., La0.97Ti0.8V0.2O3) Like the LaMO(3) end members where M = Ti, V, the LaTi1-xVxO3 phases are barely orthorhombic (almost tetragonal) and adopt the perovskite-type GdFeO3 structure (space group Pnma). Most of the LaTi1-xVxO3 phases are antiferromagnetic (AF) insulators including LaTiO3 (T-N = 148 K) and LaVO3 (T-N = 140 K). For the LaTi1-xVxO3 phases in the O < x < 0.10 region, the AF ordering temperatures and resistivities are reduced with increasing vanadium concentration. The 0.10 less than or equal to x less than or equal to 0.25 region comprises poorly metallic (rho(298) approximate to 10(-2) Omega cm), paramagnetic phases that represent rare examples of B-site-substituted metallic perovskites. Magnetic susceptibility studies in this region show Curie-Weiss behavior below 200 K with large temperature independent susceptibilities of ca. 10(-3) emu/mol. Variable-temperature synchrotron X-ray diffraction experiments on the La0.97Ti0.8V0.2O3 phase showed a marked orthorhombic distortion below 150 K but a nearly tetragonal cell at 298 K. Rietveld refinements of neutron diffraction data for this phase at 50 K showed a prototypical GdFeO3 structure with disordered Ti and V (refined occupancies of 82(1)% and 18(1)%, respectively) distributed over the octahedral site and a slight La deficiency (refined occupancy = 97(1)%). The structural parameters (bond distances, angles, cell constants) are intermediate to those of the LaMO(3) end members as expected. Electron diffraction experiments on the La0.97Ti0.8V0.2O3 phase revealed diffraction patterns that were also consistent with the prototypical Pnma cell with no evidence of microdomain ordering or supercell formation. In the 0.25 < x less than or equal to 1.0 region, the samples again show AF ordering and insulating behavior. The magnetic susceptibilities of the samples in this region show unusual peaking that is compositionally dependent. The field-cooled magnetic susceptibility of the x = 0.90 and 1.0 samples show large diamagnetic signals of unexplained origin. The zero-field cooled susceptibilities of these samples showed paramagnetic behavior. The formation of metallic phases from B-site substitution is discussed in terms of the Hubbard model. C1 UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. UNIV MARYLAND,DEPT CHEM,CTR SUPERCOND RES,COLLEGE PK,MD 20742. UNIV MARYLAND,DEPT MAT ENGN,COLLEGE PK,MD 20742. BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RI Salamanca-Riba, Lourdes/B-3785-2009; Vogt, Thomas /A-1562-2011 OI Salamanca-Riba, Lourdes/0000-0001-8155-6403; Vogt, Thomas /0000-0002-4731-2787 NR 57 TC 6 Z9 7 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD FEB PY 1996 VL 8 IS 2 BP 418 EP 427 DI 10.1021/cm950351q PG 10 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TW405 UT WOS:A1996TW40500022 ER PT J AU Tan, KM Ko, YH Parise, JB Darovsky, A AF Tan, KM Ko, YH Parise, JB Darovsky, A TI Hydrothermal growth of single crystals of TMA-CuGS-2, [C4H12N](6)[(Cu0.44Ge0.56S2.23)(4)(Ge4S8)(3)] and their characterization using synchrotron imaging plate data SO CHEMISTRY OF MATERIALS LA English DT Article ID RAY STRUCTURAL CHARACTERIZATION; DIFFRACTION; SULFIDE; SYSTEM AB Single crystals of TMA-CuGS-2, [C4H12N](6)[(CU0.44Ge0.56S2.23)(4)(Ge4S8)(3)], were synthesized hydrothermally, and the structure was determined using data collected from sealed-tube and synchrotron X-ray sources. This compound consists of Ge4S104- adamantine clusters, corner-sharing with MS(x) units (M = Cu, Ge; x = 3 or 4), forming an open framework with tetramethylammonium cations residing within four intersecting channels. Disorder in the M sites causes the composition of the framework to deviate from the ideal stoichiometry, Ge(0.71)M(0.24)S(2), realized when M = Cu and x: = 4. This is consistent with results obtained from electron-probe microanalysis. The structure refinements were carried out in space group with cell parameter alpha = 20.629 (1) Angstrom. Fourteen unique weak reflections of the type hhl, 2h + I = 4n + 2, forbidden in , were detected only in the synchrotron/imaging plate experiment. Trial refinements in space groups R3 and I2(1)3 suggest their origin in either weak ordering or multiple scattering effects. C1 SUNY STONY BROOK,DEPT CHEM,STONY BROOK,NY 11794. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973. RP Tan, KM (reprint author), SUNY STONY BROOK,DEPT EARTH & SPACE SCI,STONY BROOK,NY 11794, USA. NR 32 TC 57 Z9 57 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD FEB PY 1996 VL 8 IS 2 BP 448 EP 453 DI 10.1021/cm950375x PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TW405 UT WOS:A1996TW40500026 ER PT J AU Ko, YH Tan, KM Parise, JB Darovsky, A AF Ko, YH Tan, KM Parise, JB Darovsky, A TI Synthesis of a novel two-dimensional antimony sulfide, [C4H10N](2)[Sb8S13]center dot 0.15H(2)O, and its structure solution using synchrotron imaging plate data SO CHEMISTRY OF MATERIALS LA English DT Article ID CRYSTAL-STRUCTURE; RAY AB A novel antimony sulfide, [C4H10N](2)[Sb8S13]. 0.15H(2)O, was synthesized hydrothermally, and its structure was determined from data collected using a synchrotron/imaging plate system. The new compound consists of centrosymmetric Sb16S264- planar clusters. Each cluster is connected to four others through two edge-sharing and two corner-sharing SbS3 pyramids, forming an extended sheet. The protonated pyrrolidine molecules reside between the parallel stacked sheets. The structure is triclinic (space group ) with a = 6.929(2) Angstrom, b = 16.747(2) Angstrom, c = 17.976(4) Angstrom, alpha = 94.84(1 degrees), beta = 95.41(1)degrees, and gamma = 125.28(1)degrees. C1 SUNY STONY BROOK,DEPT CHEM,STONY BROOK,NY 11794. BROOKHAVEN NATL LAB,NATL SYNCHRTRON LIGHT SOURCE,UPTON,NY 11973. RP Ko, YH (reprint author), SUNY STONY BROOK,DEPT EARTH & SPACE SCI,CHIPR,STONY BROOK,NY 11794, USA. NR 45 TC 41 Z9 41 U1 2 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD FEB PY 1996 VL 8 IS 2 BP 493 EP 496 DI 10.1021/cm950402j PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA TW405 UT WOS:A1996TW40500033 ER PT J AU Gardner, CD Fortmann, SP Krauss, RM AF Gardner, CD Fortmann, SP Krauss, RM TI Small low-density lipoprotein particles associated with incidence of coronary artery disease in men and women SO CIRCULATION LA English DT Meeting Abstract C1 UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. STANFORD UNIV,STANFORD,CA 94305. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HEART ASSOC PI DALLAS PA 7272 GREENVILLE AVENUE, DALLAS, TX 75231-4596 SN 0009-7322 J9 CIRCULATION JI Circulation PD FEB 1 PY 1996 VL 93 IS 3 BP P15 EP P15 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA TR330 UT WOS:A1996TR33000087 ER PT J AU Williams, PT Moussa, D Blanche, PJ Terry, RB Noceti, EM Huang, Y Krauss, RM AF Williams, PT Moussa, D Blanche, PJ Terry, RB Noceti, EM Huang, Y Krauss, RM TI High density lipoprotein subclasses and LDL particle size in identical twins discordant for exercise. SO CIRCULATION LA English DT Meeting Abstract C1 LAWRENCE BERKELEY LAB,BERKELEY,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER HEART ASSOC PI DALLAS PA 7272 GREENVILLE AVENUE, DALLAS, TX 75231-4596 SN 0009-7322 J9 CIRCULATION JI Circulation PD FEB 1 PY 1996 VL 93 IS 3 BP P16 EP P16 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA TR330 UT WOS:A1996TR33000088 ER PT J AU Covey, C Sloan, LC Hoffert, MI AF Covey, C Sloan, LC Hoffert, MI TI Paleoclimate data constraints on climate sensitivity: The paleocalibration method SO CLIMATIC CHANGE LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; SEA-SURFACE TEMPERATURE; LAST GLACIAL MAXIMUM; PHANEROZOIC TIME; GLOBAL CLIMATE; MODEL; FEEDBACK; EOCENE; OCEAN; CO2 AB The relationship between paleoclimates and the future climate, while not as simple as implied in the 'paleoanalog' studies of Budyko and others, nevertheless provides sufficient constraints to broadly confirm the climate sensitivity range of theoretical models and perhaps eventually narrow the model-derived uncertainties. We use a new technique called 'paleocalibration' to calculate the ratio of temperature response to forcing on a global mean scale for three key intervals of Earth history. By examining surface conditions reconstructed from geologic data for the Last Glacial Maximum, the middle Cretaceous and the early Eocene, we can estimate the equilibrium climate sensitivity to radiative forcing changes for different extreme climates. We find that the ratios for these three periods, within error bounds, all lie in the range obtained from general circulation models: 2-5 K global warming for doubled atmospheric carbon dioxide. Paleocalibration thus provides a data-based confirmation of theoretically calculated climate sensitivity. However, when compared with paleodata on regional scales, the models show less agreeement with data. For example, our GCM simulation of the early Eocene fails to obtain the temperature contrasts between the Equator and the Poles (and between land and ocean areas) indicated by the data, even though it agrees with the temperature data in the global average. Similar results have been reported by others for the Cretaceous and for the Last Glacial Maximum. C1 UNIV CALIF SANTA CRUZ,INST MARINE SCI,SANTA CRUZ,CA 95064. NYU,DEPT EARTH SYST SCI,NEW YORK,NY 10003. RP Covey, C (reprint author), LAWRENCE LIVERMORE NATL LAB,GLOBAL CLIMATE RES DIV,MAIL CODE L-264,LIVERMORE,CA 94551, USA. NR 74 TC 27 Z9 27 U1 0 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD FEB PY 1996 VL 32 IS 2 BP 165 EP 184 DI 10.1007/BF00143708 PG 20 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA TY838 UT WOS:A1996TY83800004 ER PT J AU Menikoff, R Lackner, KS Bukiet, BG AF Menikoff, R Lackner, KS Bukiet, BG TI Modeling flows with curved detonation waves SO COMBUSTION AND FLAME LA English DT Article ID TWO-DIMENSIONAL DETONATIONS; SHOCK DYNAMICS; FRONT TRACKING; CURVATURE AB The nonzero width of a curved detonation front has a significant effect on its propagation. Physically, the curvature effect is a small but important correction. In numerical simulations, the curvature effect tends to be greatly exaggerated due to an artificially large width of an underresolved wave. In the context of reactive fluid flow, a detonation wave consists of a lead shock followed by a thin reaction zone. The curvature effect is determined by the dynamics within the reaction zone; in particular, the competition between a source term for the rate of chemical energy release and a geometric source term due to front curvature. When the width of the reaction zone is small compared with the radius of curvature of the front, the reaction zone can be approximated as quasi-steady and be modeled locally by a system of ordinary differential equations (ODEs) in which the front curvature enters as a parameter. Front curvature breaks the Galilean invariance and the quasi-steady approxmation is only valid in a distinguished frame determined by both the front curvature and the tangential velocity divergence ahead of the front. The quasi-steady ODEs determine the reaction zone profile to leading order and can be viewed as an extension of the ZND model. However, the source terms in the ODEs lead to modified Hugoniot jump conditions that take into account front curvature and reaction zone width. When the reaction zone is underresolved, a calculation in effect reduces to a ''capturing algorithm'' in which the burn model plays an analogous role for detonation waves as artificial viscosity does for shock waves. In particular, the reaction zone has an unphysically large width that is proportional to the cell size. As a consequence of the modified jump conditions, the numerical reaction zone width gives rise to an artificial curvature effect. This causes numerical solutions to depend on the cell size and orientation of a detonation front relative to the grid. Two algorithms that:eliminate numerical curvature effects are discussed, detonation shock dynamics and front tracking. C1 NEW JERSEY INST TECHNOL,CTR APPL MATH & STAT,DEPT MATH,NEWARK,NJ 07102. RP Menikoff, R (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 49 TC 19 Z9 19 U1 1 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD FEB PY 1996 VL 104 IS 3 BP 219 EP 240 DI 10.1016/0010-2180(95)00106-9 PG 22 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA TZ138 UT WOS:A1996TZ13800001 ER PT J AU Barlow, RS Carter, CD AF Barlow, RS Carter, CD TI Relationships among nitric oxide, temperature, and mixture fraction in hydrogen jet flames SO COMBUSTION AND FLAME LA English DT Article ID DIFFUSION FLAMES; NITROGEN EMISSIONS; DAMKOHLER NUMBER; TURBULENT; SUPEREQUILIBRIUM AB Simultaneous point measurements of NO, the major species, mixture fraction, temperature, and OH are obtained in nonpremixed turbulent hydrogen jet flames, using the combination of spontaneous Raman scattering, Rayleigh scattering, and laser-induced fluorescence. Results are presented for an undiluted hydrogen flame at Reynolds number 10,000 and for flames with 20% and 40% helium dilution, with emphasis on the relationships among nitric oxide, mixture fraction, and temperature. Conditional statistics are used to extract information on the coupling between reaction zone structure and measured NO levels. Fluctuations of the NO mole fraction conditional on mixture fraction are greatest near the base of the flame, where NO formation rates and concentrations are sensitive to local strain. Similarly, when NO levels are averaged conditional on both mixture fraction and temperature, the temperature dependence is strongest near the flame base, where reaction zones are thin. The radial dependence of the conditional mean NO mole fraction (conditional on mixture fraction) is shown to be small at upstream locations and negligible at the downstream locations that contribute most to the overall NO emission. These results combined with previously reported data on the present hydrogen flames provide a detailed basis for evaluation and refinement of turbulent combustion models for thermal NOx formation in jet flames. C1 SYST RES LABS INC,DAYTON,OH 45440. RP Barlow, RS (reprint author), SANDIA NATL LABS,DEPT 8351,COMBUST RES FACIL,MS 9051,LIVERMORE,CA 94551, USA. NR 21 TC 71 Z9 73 U1 1 U2 10 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD FEB PY 1996 VL 104 IS 3 BP 288 EP 299 DI 10.1016/0010-2180(95)00123-9 PG 12 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA TZ138 UT WOS:A1996TZ13800005 ER PT J AU Shugart, LR Theodorakis, C AF Shugart, LR Theodorakis, C TI Genetic ecotoxicology: The genotypic diversity approach SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY LA English DT Article; Proceedings Paper CT 15th Annual Conference of the European-Society-for-Comparative-Physiology-and-Biochemistry CY SEP 20-23, 1994 CL GENOA, ITALY SP European Soc Comparat Physiol & Biochem DE DNA; heritable effects; selection; population genetics AB Organismal responses at the genetic level to exposure to environmental genotoxicants have been well documented. An elucidation of the molecular mechanisms involved with these responses, as well as an assessment of the changes that may occur to the genetic material, will provide an understanding of the potential for deleterious consequences at higher levels of biological organization. Moreover, modem procedures of molecular biology offer the hope that alterations and changes to genetic material can be readily detected. C1 UNIV TENNESSEE, DEPT ENVIRONM TOXICOL, KNOXVILLE, TN 37916 USA. RP Shugart, LR (reprint author), OAK RIDGE NATL LAB, DIV ENVIRONM SCI, POB 2008, OAK RIDGE, TN 37831 USA. NR 13 TC 24 Z9 24 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1532-0456 J9 COMP BIOCHEM PHYS C JI Comp. Biochem. Physiol. C-Toxicol. Pharmacol. PD FEB PY 1996 VL 113 IS 2 BP 273 EP 276 DI 10.1016/0742-8413(95)02097-7 PG 4 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology SC Biochemistry & Molecular Biology; Endocrinology & Metabolism; Toxicology; Zoology GA UH465 UT WOS:A1996UH46500023 ER PT J AU Carter, ES Tung, CS AF Carter, ES Tung, CS TI NAMOT2 - A redesigned nucleic acid modeling tool: Construction of non-canonical DNA structures SO COMPUTER APPLICATIONS IN THE BIOSCIENCES LA English DT Article ID RECOGNITION; REPAIR AB Using a new set of reduced coordinates developed for describing regular and unusual nucleic acid structures, we have revised our nucleic acid modeling tool NAMOT2. NAMOT2 is general in terms of modeling different nucleic acid structures. A set of modifiable libraries allows users to customize their modeling environment. With this set of libraries, NAMOT2 can be used to model non-canonical structures such as parallel-stranded, triple-stranded and quadruple-stranded nucleic acid molecules. For modeling irregular structures (junctions, hairpin loops, etc.), we introduce a structural recipe approach. The complete procedure using NAMOT2 to construct the structure of a specific molecule is treated as the recipe for that structural motif. The existing recipes can be modified to generate new recipes for different structural motifs. Several examples of nucleic acids with non-canonical structures were modeled using NAMOT2. These examples include a DNA-drug complex, a DNA cube, a six-arm junction and a carved DNA molecule. RP Carter, ES (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 23 TC 22 Z9 22 U1 0 U2 1 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0266-7061 J9 COMPUT APPL BIOSCI JI Comput. Appl. Biosci. PD FEB PY 1996 VL 12 IS 1 BP 25 EP 30 PG 6 WC Computer Science, Interdisciplinary Applications SC Computer Science GA UB717 UT WOS:A1996UB71700004 PM 8670616 ER PT J AU Guan, XJ Uberbacher, EC AF Guan, XJ Uberbacher, EC TI Alignments of DNA and protein sequences containing frameshift errors SO COMPUTER APPLICATIONS IN THE BIOSCIENCES LA English DT Article AB Molecular sequences, like all experimental data, are subject to error. Many current DNA sequencing protocols have very significant error rates and often generate artefactual insertions and deletions of bases (indels) which corrupt the translation of sequences and compromise the detection of protein homologies. The impact of these errors on the utility of molecular sequence data is dependent on the analytic technique used to interpret the data. In the presence of frameshift errors, standard algorithms using six-frame translation can miss important homologies because only subfragments of the correct translation are available in any given frame. We present a new algorithm which can detect and correct frameshift errors in DNA sequences during comparison of translated sequences with protein sequences in the databases. This algorithm can recognize homologous proteins sharing 30% identity even in the presence of a 7% frameshift error rate. Our algorithm uses dynamic programming, producing a guaranteed optimal alignment in the presence of frameshifts, and has a sensitivity equivalent to Smith-Waterman. The computational efficiency of the algorithm is O(nm) where n and m are the sizes of two sequences being compared. The algorithm does not rely on prior knowledge or heurisitic rules and performs significantly better than any previously reported method. RP OAK RIDGE NATL LAB, DIV MATH & COMP SCI, OAK RIDGE, TN 37831 USA. NR 10 TC 32 Z9 34 U1 1 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0266-7061 J9 COMPUT APPL BIOSCI JI Comput. Appl. Biosci. PD FEB PY 1996 VL 12 IS 1 BP 31 EP 40 PG 10 WC Computer Science, Interdisciplinary Applications SC Computer Science GA UB717 UT WOS:A1996UB71700005 PM 8670617 ER PT J AU delPilarValencia, M Miller, LH Mazur, P AF delPilarValencia, M Miller, LH Mazur, P TI Permeability of intact and dechorionated eggs of the Anopheles mosquito to water vapor and liquid water: A comparison with Drosophila SO CRYOBIOLOGY LA English DT Article ID EMBRYOS AB As an initial step in the development of cryopreservation methods for Allopheles gambiae embryos, we determined the permeability of intact and dechorionated A. gambiae embryos to water and ethylene glycol and compared those permeabilities with those of Drosophila melanogaster embryos. Most studies were conducted on embryos allowed to develop For 8 h at 26 degrees C or 15 h at 17 degrees C. Intact A. gambiae embryos are some 50 times more permeable to water vapor than are D. melanogaster embryos; e.g., when air dried, half of 15 h/17 degrees C A. gambiae embryos become severely dehydrated in 3.5-4.0 min, whereas comparably aged D. melanogaster embryos require similar to 4 h or more. Comparable differences between the two species exist with respect to the loss of liquid water under an osmotic driving force. After 90 min in 0.75 M sucrose in 0.26 osmolal D-20 Drosophila medium, 25-40% of intact A. gambiae embryos underwent extensive shrinkage, whereas D. melanogaster embryos showed no shrinkage. The chorion of both species can be removed by a 2.5-min exposure to 50% household bleach (Clorox). Dechorionation increases the rate of water loss two- to sixfold during air drying in both species and during exposure to hyperosmotic sucrose in A. gambiae. Dechorionated D. melanogaster embryos, however, show no shrinkage in hyperosmotic sucrose even after 6 h. The water permeability of dechorionated A. gambiae embryos thus remains many-fold higher than that of dechorionated D. melanogaster embryos. Although moderately permeable to water, neither intact nor dechorionated A. gambiae embryos are permeable to ethylene glycol, as evidenced by the failure of dehydrated embryos to reexpand in 120-180 min in that solution. (C) 1996 Academic Press. Inc. C1 OAK RIDGE NATL LAB, DIV BIOL, OAK RIDGE, TN 37831 USA. RP delPilarValencia, M (reprint author), NIH, PARASIT DIS LAB, BETHESDA, MD 20892 USA. NR 14 TC 20 Z9 20 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0011-2240 EI 1090-2392 J9 CRYOBIOLOGY JI Cryobiology PD FEB PY 1996 VL 33 IS 1 BP 142 EP 148 DI 10.1006/cryo.1996.0014 PG 7 WC Biology; Physiology SC Life Sciences & Biomedicine - Other Topics; Physiology GA UH228 UT WOS:A1996UH22800014 PM 8812093 ER PT J AU delPilarValencia, M Miller, LH Mazur, P AF delPilarValencia, M Miller, LH Mazur, P TI Permeabilization of eggs of the malaria mosquito Anopheles gambiae SO CRYOBIOLOGY LA English DT Article ID DROSOPHILA-MELANOGASTER EMBRYOS; CRYOPRESERVATION AB Although Anopheles gambiae embryos that have developed for 15 h at 17 degrees C are slightly permeable to water, they are impermeable to ethylene glycol, the cryoprotectant used in the cryopreservation of Drosophila melanogaster embryos. Success in cryopreservation requires that they be made permeable to protective solutes. Permeabilization of D. melanogaster was achieved by 1) dechorionation with 50% Clorox (household bleach) followed by 2) a water flush; 3) immersion in isopropyl alcohol to remove most extraembryonic water; 4) 2 min air drying to remove most isopropyl alcohol; 5) 90-s exposure to n-heptane containing 0.3% 1-butanol; and 6) 15-s exposure to pure n-heptane. The permeability of A. gambiae embryos was assessed by determining the times required for the initial dehydration of embryos in 1 M ethylene glycol in 260 mOsm Drosophila culture medium (permeability to water) and the times required for their return to normal volume (permeability to ethylene glycol). Based on these criteria, the above D. melanogaster procedure effectively permeabilizes 15 h/17 degrees C to 19 h/17 degrees C A. gambiae embryos. Nearly all collapsed in <5 min, and most returned to normal volume in similar to 40 min. Although permeable, all were killed by the permeabilization procedure. In analyzing the effect of each step on viability, 50% Clorox caused some lethality, and Clorox followed by isopropyl alcohol was 100% lethal. Decreasing the Clorox concentration to 10% still dechorionated eggs, but with reduced toxicity; substitution of a 10% solution of reagent-grade sodium hypochlorite for Clorox further decreased toxicity. The isopropyl alcohol step was also toxic. Consequently, the removal of residual surface water was achieved by substituting air drying for isopropyl alcohol. The drying took place under direct microscope observation and was continued until the embryos began to shrink. The combination of this modified method for dechorionation and controlled air drying before exposure to heptane resulted in permeabilization of all embryos in most runs and in similar to 30% survival of the permeabilized embryos. (C) 1996 Academic Press, Inc. C1 OAK RIDGE NATL LAB, DIV BIOL, OAK RIDGE, TN 37831 USA. RP delPilarValencia, M (reprint author), NIH, PARASIT DIS LAB, BETHESDA, MD 20892 USA. NR 16 TC 16 Z9 16 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0011-2240 EI 1090-2392 J9 CRYOBIOLOGY JI Cryobiology PD FEB PY 1996 VL 33 IS 1 BP 149 EP 162 DI 10.1006/cryo.1996.0015 PG 14 WC Biology; Physiology SC Life Sciences & Biomedicine - Other Topics; Physiology GA UH228 UT WOS:A1996UH22800015 PM 8812094 ER PT J AU Fisk, Z Sarrao, JL Thompson, JD AF Fisk, Z Sarrao, JL Thompson, JD TI Heavy fermions SO CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE LA English DT Review ID MAGNETIC EXCITATION SPECTRUM; CE3BI4PT3; GAP; SUPERCONDUCTIVITY; IMPURITIES; CENISN; UBE13; STATE; SMB6 AB Although the heavy fermion problem is nearly twenty years old, progress is still being made, especially as experimental techniques and theoretical ideas developed for the cuprates are applied to the heavy fermion problem. Recent advances in heavy fermion physics have been made in in four specific areas: superconductivity, Fermi surface measurements, marginal Fermi liquid behavior, and Kondo insulators. C1 FLORIDA STATE UNIV,DEPT PHYS,TALLAHASSEE,FL 32306. UNIV CALIF LOS ALAMOS NATL LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. RP Fisk, Z (reprint author), FLORIDA STATE UNIV,NATL HIGH MAGNET FIELD LAB,TALLAHASSEE,FL 32306, USA. NR 21 TC 8 Z9 8 U1 3 U2 15 PU CURRENT SCIENCE LTD PI LONDON PA 34-42 CLEVELAND STREET, LONDON, ENGLAND W1P 6LB SN 1359-0286 J9 CURR OPIN SOLID ST M JI Curr. Opin. Solid State Mat. Sci. PD FEB PY 1996 VL 1 IS 1 BP 42 EP 46 DI 10.1016/S1359-0286(96)80008-8 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA VE412 UT WOS:A1996VE41200008 ER PT J AU ONeill, RV Kahn, JR Duncan, JR Elliott, S Efroymson, R Cardwell, H Jones, DW AF ONeill, RV Kahn, JR Duncan, JR Elliott, S Efroymson, R Cardwell, H Jones, DW TI Economic growth and sustainability: A new challenge SO ECOLOGICAL APPLICATIONS LA English DT Article C1 UNIV TENNESSEE,DEPT ECON,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,HLTH SCI RES DIV,OAK RIDGE,TN 37831. UNIV TENNESSEE,ECOL PROGRAM,KNOXVILLE,TN 37996. RP ONeill, RV (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,POB 2008,OAK RIDGE,TN 37831, USA. NR 1 TC 10 Z9 10 U1 1 U2 3 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD FEB PY 1996 VL 6 IS 1 BP 23 EP 24 DI 10.2307/2269544 PG 2 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA TU567 UT WOS:A1996TU56700008 ER PT J AU Zak, DR Ringelberg, DB Pregitzer, KS Randlett, DL White, DC Curtis, PS AF Zak, DR Ringelberg, DB Pregitzer, KS Randlett, DL White, DC Curtis, PS TI Soil microbial communities beneath Populus grandidentata crown under elevated atmospheric CO2 SO ECOLOGICAL APPLICATIONS LA English DT Article DE climate change; elevated atmospheric CO2; microbial biomass; microbial communities; phospholipid fatty acids; Populus grandidentata; rhizosphere; soil actinomycetes; soil bacteria; soil fungi ID NUTRIENT-UPTAKE; CARBON-DIOXIDE; CLIMATE-CHANGE; AMENDED SOIL; BIOMASS; GROWTH; RHIZOSPHERE; CALIBRATION; FEEDBACK; FORESTS AB In most terrestrial ecosystems, the amount of substrate entering the soil from plant litter production is only sufficient to meet the maintenance requirements of soil microorganisms, allowing for no net annual growth. However, the rising atmospheric CO2 concentration has the potential to alter such a balance by increasing plant litter production, and hence the amount of substrate available for heterotrophic metabolism in soil. In a recent experiment, we observed that greater belowground plant litter production at elevated atmospheric CO2 significantly increased the biomass of soil microorganisms in both rhizosphere and non-rhizosphere soil. Because soil microorganisms differ in their ability to convert substrate into biomass, we hypothesized that greater plant litter production at elevated CO2 should shift community composition as fungal populations increase in response to greater substrate availability. We used a molecular technique, phospholipid fatty acid (PLFA) analysis, to gain insight into the composition of soil microbial communities beneath Populus grandidentata growing at ambient and twice-ambient atmospheric CO2. PLFAs extracted from rhizosphere and non-rhizosphere soil were derivatized and identified using gas chromatography and mass spectrometry. After one growing season the proportions of bacterial, actinomycetal, and fungal PLFAs were not significantly influenced by elevated atmospheric CO2 in either rhizosphere or non-rhizosphere soil. However, clear differences were present between microbial communities in rhizosphere and non-rhizosphere soil. Although enhanced belowground plant litter production under elevated atmospheric CO2 increased the biomass of soil microorganisms, we have no evidence to suggest that such an increase occurred through a shift in community composition, at least in the short term. C1 UNIV TENNESSEE,CTR ENVIRONM BIOTECHNOL,KNOXVILLE,TN 37801. MICHIGAN TECHNOL UNIV,SCH FORESTRY & WOOD PROD,HOUGHTON,MI 49931. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. OHIO STATE UNIV,DEPT PLANT BIOL,COLUMBUS,OH 43210. RP Zak, DR (reprint author), UNIV MICHIGAN,SCH NAT RESOURCES & ENVIRONM,ANN ARBOR,MI 48109, USA. RI Zak, Donald/C-6004-2012 NR 37 TC 143 Z9 163 U1 3 U2 42 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE, NW, STE 400, WASHINGTON, DC 20036 SN 1051-0761 J9 ECOL APPL JI Ecol. Appl. PD FEB PY 1996 VL 6 IS 1 BP 257 EP 262 DI 10.2307/2269568 PG 6 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA TU567 UT WOS:A1996TU56700032 ER PT J AU Peters, EL Brisbin, IL AF Peters, EL Brisbin, IL TI Environmental influences on the Cs-137 kinetics of the yellow-bellied turtle (Trachemys scripta) SO ECOLOGICAL MONOGRAPHS LA English DT Article DE biogeochemistry; biotic concentrations; cesium-137; contaminant modeling; diet; kinetics modeling; model sensitivity analysis; physiological ecology; radioecology; radionuclides; Richards sigmoidal model; stochastic models; Testudines; thermal ecology; Trachemys scripta ID CHERNOBYL REACTOR ACCIDENT; FOOD-CHAIN MODEL; PSEUDEMYS-SCRIPTA; RADIONUCLIDE INGESTION; COOLING RESERVOIR; BODY SIZE; TURNOVER; RETENTION; GROWTH; TEMPERATURE AB Assessments of ecological risk require accurate predictions of contaminant dynamics in natural populations. However, simple deterministic models that assume constant uptake rates and elimination fractions may compromise both their ecological realism and their general application to animals with variable metabolisms or diets. In particular, the temperature-dependent metabolic rates characteristic of ectotherms may lead to significant differences between observed and predicted contaminant kinetics. We examined the influence of a seasonally variable thermal environment on predicting the uptake and annual cycling of contaminants by ectotherms, using a temperature-dependent model of Cs-137 kinetics in free-living yellow-bellied turtles, Trachemys scripta. We compared predictions from this model with those of deterministic negative exponential and flexibly shaped Richards sigmoidal models. Concentrations of Cs-137 in a population of this species in Pond B, a radionuclide-contaminated nuclear reactor cooling reservoir, and Cs-137 uptake by uncontaminated turtles held captive in Pond B for 4 yr confirmed both the pattern of uptake and the equilibrium concentrations predicted by the temperature-dependent model. Almost 90% of the variance in the predicted time-integrated Cs-137 concentration was explainable by linear relationships with model parameters. The model was also relatively insensitive to uncertainties in the estimates of ambient temperature, suggesting that adequate estimates of temperature-dependent ingestion and elimination may require relatively few measurements of ambient conditions at sites of interest. Analyses of Richards sigmoidal models of Cs-137 uptake indicated significant differences from a negative exponential trajectory in the Ist yr after the turtles' release into Pond B, We also observed significant annual cycling of Cs-137 concentrations, apparently due to temperature-dependent metabolism and its influence on ingestion and elimination rates, However, equilibrium concentrations of the radionuclide in the wild population were predictable from negative exponential models based on average annual temperature and its effects on intake and elimination rates, also suggesting that predicting ectotherm responses to long-lived contaminants (such as Cs-137) may be possible without complex ecophysiological modeling. C1 COLORADO STATE UNIV, DEPT RADIOL HLTH SCI, FT COLLINS, CO 80523 USA. RP UNIV GEORGIA, SAVANNAH RIVER ECOL LAB, PO DRAWER E, AIKEN, SC 29802 USA. NR 73 TC 16 Z9 16 U1 1 U2 8 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0012-9615 EI 1557-7015 J9 ECOL MONOGR JI Ecol. Monogr. PD FEB PY 1996 VL 66 IS 1 BP 115 EP 136 DI 10.2307/2963483 PG 22 WC Ecology SC Environmental Sciences & Ecology GA TZ428 UT WOS:A1996TZ42800005 ER PT J AU Hardesty, D AF Hardesty, D TI Lasers make better steel ... SO ELECTRONICS WORLD LA English DT Editorial Material RP Hardesty, D (reprint author), SANDIA NATL LABS,SANDIA COMBUST RES FACIL,MS 0167,ALBUQUERQUE,NM 87185, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU REED BUSINESS PUBLISHING LTD PI SUTTON PA QUADRANT HOUSE THE QUADRANT, SUTTON, SURREY, ENGLAND SM2 5AS SN 0959-8332 J9 ELECTRON WORLD JI Electron. World PD FEB PY 1996 IS 1719 BP 98 EP 98 PG 1 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA UD353 UT WOS:A1996UD35300012 ER PT J AU Nakarado, GL AF Nakarado, GL TI A marketing orientation is the key to a sustainable energy future SO ENERGY POLICY LA English DT Article DE renewable energy; marketing; customer preference AB This paper presents a sampling of recent research indicating a customer preference (demand) for renewable energy as a unique 'variety' or 'brand' of power. Market oriented industry growth tightly coupled to segmented end-use consumer preferences will ultimately be more robust and sustainable. Examples of emerging alternative models for renewable energy development are given in the conclusion. RP Nakarado, GL (reprint author), NATL RENEWABLE ENERGY LAB,1617 COLE BLVD,GOLDEN,CO 80401, USA. NR 23 TC 12 Z9 12 U1 0 U2 2 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD FEB PY 1996 VL 24 IS 2 BP 187 EP 193 DI 10.1016/0301-4215(95)00098-4 PG 7 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA TV923 UT WOS:A1996TV92300008 ER PT J AU Scheidegger, AM Lamble, GM Sparks, DL AF Scheidegger, AM Lamble, GM Sparks, DL TI Investigation of Ni sorption on pyrophyllite: An XAFS study SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID X-RAY ABSORPTION; OXIDE-WATER INTERFACE; SURFACE PRECIPITATION; AQUEOUS-SOLUTIONS; POLYHEDRAL APPROACH; CLAY-MINERALS; FERRIC OXIDES; ADSORPTION; SPECTROSCOPY; KAOLINITE AB Sorption reactions at the solid-water interface decrease solute mobility and often control the fate, bioavailability, and transport of metal ions in soils and groundwaters. A thorough understanding of the structural environment of metals at the solid-water interface is therefore of fundamental importance. In this study, X-ray absorption fine structure (XAFS) spectroscopy was used to discern the local atomic structure of Ni(ll) sorbed onto pyrophyllite. The first coordination shell consists of 6 O atoms at 2.02-2.04 Angstrom. For the second shell, XAFS data suggest a single Ni-AI/Si distance (2.96-3.03 Angstrom), indicative of edge sharing of Ni and Al octahedra and possibly the presence of mixed nickel-aluminum hydroxides. As Ni surface loading on pyrophyllite increased, the number of Ni second-neighbor atoms at a distance of 2.99-3.00 Angstrom increased from N approximate to 1 to N approximate to 5. The presence of multinuclear surface complexes was depicted at low surface loading and at reaction conditions undersaturated with respect to the formation of Ni(OH)(2)(s). This observation suggests that the total coverage of surface sites is not necessary for the formation of multinuclear surface complexes and implies that the pyrophyllite surface promotes hydrolysis and multinuclear complex formation. C1 BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. RP Scheidegger, AM (reprint author), UNIV DELAWARE, DEPT PLANT & SOIL SCI, NEWARK, DE 19717 USA. NR 59 TC 114 Z9 118 U1 5 U2 22 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X EI 1520-5851 J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB PY 1996 VL 30 IS 2 BP 548 EP 554 DI 10.1021/es950293+ PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA TT496 UT WOS:A1996TT49600045 ER PT J AU Francis, AJ JoshiTope, GA Dodge, CJ AF Francis, AJ JoshiTope, GA Dodge, CJ TI Biodegradation of nickel-citrate and modulation of nickel toxicity by iron SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID COMPLEX-FORMATION; MICROORGANISMS; MIGRATION; SYSTEMS; AGENTS; METALS; OXIDES; SITE; IONS AB Biodegradation of 1:1 nickel:citric acid by Pseudomonas fluorescens proceeded after a lag (similar to 17 h) at the rate of 11 +/- 1 mu mol h(-1), with only partial mineralization of the complex. The incomplete degradation of the complex was not attributed to changes in its structure, but was due to the toxicity of the Ni released. Addition of 1:1 Ni:citric acid inhibited glucose metabolism by the bacterium. The toxicity of the released Ni was evident only when it attained a threshold concentration of >0.3 mM in the culture medium. Speciation calculations showed that Ni released after metabolism of the complex was present as Ni2+ ion and nickel carbonate. Addition of iron as a ferric hydroxide or 1:1 Fe:citric acid to 1:1 Ni:citric acid resulted in the complete metabolism of the Ni-citrate complex, with concurrent removal of the released Ni from solution by coprecipitation with iron. RP Francis, AJ (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 29 TC 23 Z9 23 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB PY 1996 VL 30 IS 2 BP 562 EP 568 DI 10.1021/es950312f PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA TT496 UT WOS:A1996TT49600047 ER PT J AU Alvarez, AJ Yumet, GM Santiago, CL Hazen, TC Chaudhry, R Toranzos, GA AF Alvarez, AJ Yumet, GM Santiago, CL Hazen, TC Chaudhry, R Toranzos, GA TI In situ survival of genetically engineered microorganisms in a tropical aquatic environment SO ENVIRONMENTAL TOXICOLOGY AND WATER QUALITY LA English DT Article ID ESCHERICHIA-COLI; LAKE WATER; GENE; BACTERIA; SOIL; RNA AB In this study, the survival of genetically engineered microorganisms (GEMs) and their interactions with the environmental microbiota of a tropical river was investigated. Diffusion chambers were used for the in situ survival experiments with a nonplasmid containing Escherichia coli DH1 strain and two model GEMs, E. coli JM103 containing a 2.6 kilobase plasmid (pUCS) and E. coli DH1 with a 4.8 kb plasmid (pWTAla5'). Pure culture survival studies indicated that after a week in the environment a 1.0 log(10) decrease in bacterial numbers occurred for both E. coli DH1, while a 3.0 log(10) reduction was observed for E. coli JM103. However, a reduction of 4.0 log(10) was observed for the E. coli DH1 (pWTAla5') when placed in a chamber conjointly with the resident microbiota. The data suggest that the presence of a plasmid makes no difference on the survival time of GEMs, whereas the presence of competing bacteria is ultimately what limits the survival time of GEMs in the environment. (C) 1996 by John Wiley & Sons, Inc. C1 UNIV PUERTO RICO,DEPT BIOL,RIO PIEDRAS,PR 00931. SAVANNAH RIVER ECOL LAB,DIV ENVIRONM SCI,AIKEN,SC 29808. OAKLAND UNIV,DEPT BIOL SCI,ROCHESTER,MI 48309. RI Hazen, Terry/C-1076-2012 OI Hazen, Terry/0000-0002-2536-9993 NR 20 TC 3 Z9 3 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 1053-4725 J9 ENVIRON TOXIC WATER JI Environ. Toxicol. Water Quality PD FEB PY 1996 VL 11 IS 1 BP 21 EP 25 DI 10.1002/(SICI)1098-2256(1996)11:1<21::AID-TOX4>3.0.CO;2-B PG 5 WC Environmental Sciences; Toxicology; Water Resources SC Environmental Sciences & Ecology; Toxicology; Water Resources GA TU211 UT WOS:A1996TU21100004 ER PT J AU Morante, S Furenlid, L Schiavo, G Tonello, F Zwilling, R Montecucco, C AF Morante, S Furenlid, L Schiavo, G Tonello, F Zwilling, R Montecucco, C TI X-ray absorption spectroscopy study of zinc coordination in tetanus neurotoxin, astacin, alkaline protease and thermolysin SO EUROPEAN JOURNAL OF BIOCHEMISTRY LA English DT Article DE X-ray absorption spectroscopy; extended X-ray absorption fine structure; zinc-endopeptidases ID 3-DIMENSIONAL STRUCTURE; FINE-STRUCTURE; EDGE STRUCTURE; NEUROTRANSMITTER RELEASE; PSEUDOMONAS-AERUGINOSA; SNAKE-VENOM; METALLOPROTEINASES; DEOXYHEMOGLOBIN; COLLAGENASES; INHIBITION AB Tetanus and botulinum neurotoxins constitute a new group of Zn-endopeptidases which has recently been actively investigated with the purpose of correlating their biochemical properties to their neurobiocytosis inhibitory capacity. Crystallographic data show that Zn-endopeptidases are characterized by an active site with a Zn atom coordinated to two histidines and a glutamate-bound water molecule. The two histidines and the glutamate residues belong to the HEXXH motif which is characteristic of most Zn-endopeptidases. A fourth metal ligand is a glutamate in thermolysin-like proteinases, but it is an histidine in the astacin family of proteinases and in alkaline protease. Astacin and alkaline protease possess a tyrosine as fifth Zn ligand, whose position in the case of alkaline protease could not be determined by X-ray crystallography. Not much is known about the atom arrangement around the active site in tetanus neurotoxin. In this work X-ray absorption spectroscopy has been used to obtain information on the Zn coordination mode in tetanus neurotoxin. The near-edge and extended fine-structure absorption spectra of this toxin are compared with those of astacin, alkaline protease and thermolysin. The present data and sequence information suggest a new pattern of Zn coordination in tetanus neurotoxin with one water molecule and three aromatic residues as metal ligands. These residues are the two histidines of the characteristic motif and a tyrosine which is tentatively identified with Tyr242, on the basis of sequence comparison and mutagenesis experiments. The mean distances of the Zn from the nearest coordinated atoms is reported. Our results indicate that alkaline protease, like astacin, also possesses a tyrosine as a fifth ligand. C1 BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE DEPT,UPTON,NY 11973. CTR CNR BIOMEMBRANE,DIPARTIMENTO SCI BIOMED,PADUA,ITALY. UNIV HEIDELBERG,ZOOL INST PHYSIOL,HEIDELBERG,GERMANY. RP Morante, S (reprint author), UNIV ROMA TOR VERGATA,DIPARTIMENTO FIS,VIA RIC SCI,I-00133 ROME,ITALY. OI Morante, Silvia/0000-0002-3913-5733; Schiavo, Giampietro/0000-0002-4319-8745 FU Telethon [473] NR 48 TC 16 Z9 16 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0014-2956 J9 EUR J BIOCHEM JI Eur. J. Biochem. PD FEB 1 PY 1996 VL 235 IS 3 BP 606 EP 612 DI 10.1111/j.1432-1033.1996.00606.x PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA TU397 UT WOS:A1996TU39700021 PM 8654408 ER PT J AU Stubbs, JB AF Stubbs, JB TI Effect of revised ICRP recommendations on krypton-81m dosimetry - Or a discrepancy? Reply SO EUROPEAN JOURNAL OF NUCLEAR MEDICINE LA English DT Letter RP Stubbs, JB (reprint author), OAK RIDGE INST SCI & EDUC,DIV MED SCI,RADIAT INTERNAL DOSE INFORMAT CTR,OAK RIDGE,TN 37831, USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0340-6997 J9 EUR J NUCL MED JI Eur. J. Nucl. Med. PD FEB PY 1996 VL 23 IS 2 BP 228 EP 229 DI 10.1007/BF01731852 PG 2 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA TW341 UT WOS:A1996TW34100019 ER PT J AU Amann, A Visani, P Aupke, K Mota, AC Maple, MB Dalichaouch, Y Armstrong, PE Fisk, Z AF Amann, A Visani, P Aupke, K Mota, AC Maple, MB Dalichaouch, Y Armstrong, PE Fisk, Z TI Unconventional vortex dynamics in the low-field superconducting phases of UPt3 SO EUROPHYSICS LETTERS LA English DT Article ID FLUX MOTION; RELAXATION; DIAGRAM; POINT AB The flux dynamics at low magnetic fields in UPt3 shows a clear distinction between the relaxation of bulk vortices and those close to the surface. In addition, in the high-temperature A-phase, vortices trapped in the bulk of the specimen after cycling it in a magnetic field creep out as expected, while bulk vortices in the B-phase remain strongly pinned, indicating that an intrinsic, novel pinning mechanism exists in the low-temperature superconducting phase of UPt3. C1 UNIV CALIF SAN DIEGO,DEPT PHYS,LA JOLLA,CA 92093. UNIV CALIF SAN DIEGO,IPAP,LA JOLLA,CA 92093. LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545. RP Amann, A (reprint author), ETH ZURICH,FESTKORPERPHYS LAB,CH-8093 ZURICH,SWITZERLAND. NR 17 TC 5 Z9 5 U1 0 U2 1 PU EDITIONS PHYSIQUE PI LES ULIS CEDEX PA Z I DE COURTABOEUF AVE 7 AV DU HOGGAR, BP 112, 91944 LES ULIS CEDEX, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD FEB 1 PY 1996 VL 33 IS 4 BP 303 EP 308 DI 10.1209/epl/i1996-00337-8 PG 6 WC Physics, Multidisciplinary SC Physics GA TW189 UT WOS:A1996TW18900009 ER PT J AU Armstrong, GA Hearst, JE AF Armstrong, GA Hearst, JE TI Carotenoids .2. Genetics and molecular biology of carotenoid pigment biosynthesis SO FASEB JOURNAL LA English DT Review DE phytoene; lycopene cyclization; cyclic xanthophylls; xanthophyll glycosides; beta-carotene; provitamin A ID GERANYLGERANYL PYROPHOSPHATE SYNTHASE; ERWINIA-HERBICOLA; NEUROSPORA-CRASSA; ESCHERICHIA-COLI; RHODOBACTER-CAPSULATUS; PHYTOENE DESATURASE; NUCLEOTIDE-SEQUENCE; BETA-CAROTENE; ZETA-CAROTENE; CLONING AB The crucial roles of carotenoids and their metabolites in photooxidative protection and photosynthesis, not to mention nutrition, vision, and cellular differentiation, make them an important and complex class of biological pigments, Significant advances within the last few years have enhanced our understanding of the genetics and molecular biology of carotenoid biosynthesis in bacteria, fungi, algae, and plants, All of the genes involved in carotenoid biosynthesis from Rhodobacter capsulatus, an anoxygenic photosynthetic bacterium, and from several species of Erwinia, nonphotosynthetic bacteria, have been molecularly characterized, Recent studies have revealed that two early enzymes of carotenoid biosynthesis, geranylgeranyl pyrophosphate synthase and phytoene synthase, are structurally and functionally related in all carotenogenic organisms, In contrast, the subsequent conversion of phytoene, the first C-40 carotenoid, to beta-carotene requires two desaturases and one cyclase in oxygenic photosynthetic organisms (cyanobacteria, algae, and higher plants) but only one structurally distinct desaturase and a structurally distinct cyclase in other carotenogenic bacteria and in fungi, Studies of the enzymes that introduce oxygen-containing functional groups into carotenes to produce xanthophylls, the vast majority of all carotenoids, are still in their infancy, This review summarizes the most recent developments in carotenoid biosynthesis from a molecular genetic standpoint. C1 LAWRENCE BERKELEY LAB,STRUCT BIOL DIV,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP Armstrong, GA (reprint author), ETH ZURICH,INST PLANT SCI,CH-8092 ZURICH,SWITZERLAND. NR 64 TC 163 Z9 172 U1 3 U2 23 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 SN 0892-6638 J9 FASEB J JI Faseb J. PD FEB PY 1996 VL 10 IS 2 BP 228 EP 237 PG 10 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA TY962 UT WOS:A1996TY96200007 PM 8641556 ER PT J AU Maurer, G Prausnitz, JM AF Maurer, G Prausnitz, JM TI Thermodynamics of phase equilibrium for systems containing gels SO FLUID PHASE EQUILIBRIA LA English DT Article DE theory; methods of calculation; phase equilibria; gels; polymers ID TEMPERATURE-SENSITIVE GELS; N-ISOPROPYLACRYLAMIDE GELS; SWELLING EQUILIBRIA; MECHANICAL-BEHAVIOR; VOLUME CHANGES; IONIC GELS; TRANSITION; POLYMER; PREDICTIONS; HYDROGELS AB A gel is a three-dimensional cross-linked elastic polymer. When a gel is immersed into a liquid, it can swell, similar to a sponge. If the surrounding liquid is a solute-containing solution, a solute partitions between the gel and the surrounding liquid. This work derives the fundamental equations of phase equilibrium for such systems. These equations take into account the elastic properties of the gel. Criteria are given for the distribution of solutes between a gel and a coexisting liquid phase. Criteria are also presented for calculating three-phase equilibria where a swollen gel and a collapsed gel coexist with the surrounding liquid. Attention is given to a slightly ionized gel (polyelectrolyte) surrounded by a dilute aqueous electrolyte solution. The equations of equilibrium show that, when Donnan equilibria are taken into account, the pH inside the gel is not equal to that of the surrounding aqueous solution. The discussion presented here may be useful for design of gels used in medicine, pharmacy and biotechnology. C1 UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. NR 33 TC 64 Z9 65 U1 1 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD FEB PY 1996 VL 115 IS 1-2 BP 113 EP 133 DI 10.1016/0378-3812(95)02829-3 PG 21 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA UB582 UT WOS:A1996UB58200007 ER PT J AU McDowell, JM Huang, SR McKinney, EC An, YQ Meagher, RB AF McDowell, JM Huang, SR McKinney, EC An, YQ Meagher, RB TI Structure and evolution of the actin gene family in Arabidopsis thaliana SO GENETICS LA English DT Article ID PREPROPHASE BAND ORGANIZATION; F-ACTIN; DIFFERENTIAL EXPRESSION; MOLECULAR EVOLUTION; CELLS; COMPLEX; PLANTS; DNA; SUBSTITUTION; MICROTUBULE AB Higher plants contain families of actin-encoding genes that are divergent and differentially expressed. Progress in understanding the functions and evolution of plant actins has been hindered by the large size of the actin gene families. In this study, we characterized the structure and evolution of the actin gene family in Arabidopsis thaliana. DNA blot analyses with gene-specific probes suggested that all 10 of the Arabidopsis actin gene family members have been isolated and established that Arabidopsis has a much simpler actin gene family than other plants that have been examined. Phylogenetic analyses suggested that the Arabidopsis gene family contains at least two ancient classes of genes that diverged early in land plant evolution and may have separated vegetative from reproductive actins. Subsequent divergence produced a total of six distinct subclasses of actin, and five showed a distinct pattern of tissue specific expression. The concordance of expression patterns with the phylogenetic structure is discussed. These subclasses appear to be evolving independently, as no evidence of gene conversion was found. The Arabidopsis actin proteins have an unusually large number of nonconservative amino acid substitutions, which mapped to the surface of the actin molecule, and should effect protein-protein interactions. C1 UNIV GEORGIA,DEPT GENET,ATHENS,GA 30602. UNIV N CAROLINA,DEPT BIOL,CHAPEL HILL,NC 27599. UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. OI McDowell, John/0000-0002-9070-4874 NR 60 TC 134 Z9 159 U1 0 U2 6 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 SN 0016-6731 J9 GENETICS JI Genetics PD FEB PY 1996 VL 142 IS 2 BP 587 EP 602 PG 16 WC Genetics & Heredity SC Genetics & Heredity GA TR639 UT WOS:A1996TR63900024 PM 8852856 ER PT J AU Milosavljevic, A Zeremski, M Strezoska, Z Grujic, D Dyanov, H Batus, S Salbego, D Paunesku, T Soares, MB Crkvenjakov, R AF Milosavljevic, A Zeremski, M Strezoska, Z Grujic, D Dyanov, H Batus, S Salbego, D Paunesku, T Soares, MB Crkvenjakov, R TI Discovering distinct genes represented in 29,570 clones from infant brain cDNA libraries by applying sequencing by hybridization methodology SO GENOME RESEARCH LA English DT Article ID TAGS AB To discover all distinct human genes and to determine their patterns of expression across different cell types, developmental stages, and physiological conditions, a procedure is needed for fast, mutual comparison of hundreds of thousands (and perhaps millions) of clones from cDNA libraries, a; well as their comparison against data bases of sequenced DNA. In a pilot study, 29,570 clones in duplicate from both original and normalized, directional, infant brain cDNA libraries were hybridized with 107-215 heptamer oligonucleotide probes to obtain oligonucleotide sequence signatures (OSSs). The OSSs were compared and clustered based on mutual similarity into 16,741 clusters, each corresponding to a distinct cDNA. A number of distinct cDNAs were successfully recognized by matching their 107-probe OSSs against GenBank entries, indicating the possibility of sequence recognition with only a few hundred randomly chosen oligomers. C1 ARGONNE NATL LAB,CTR MECHANIST BIOL & BIOTECHNOL,GENOME STRUCT GRP,ARGONNE,IL 60439. NEW YORK STATE PSYCHIAT INST & HOSP,NEW YORK,NY 10032. COLUMBIA UNIV COLL PHYS & SURG,DEPT PSYCHIAT,NEW YORK,NY 10032. RI Paunesku, Tatjana/A-3488-2017 OI Paunesku, Tatjana/0000-0001-8698-2938 NR 18 TC 20 Z9 22 U1 0 U2 0 PU COLD SPRING HARBOR LAB PRESS PI PLAINVIEW PA 1 BUNGTOWN RD, PLAINVIEW, NY 11724 SN 1054-9803 J9 GENOME RES JI Genome Res. PD FEB PY 1996 VL 6 IS 2 BP 132 EP 141 DI 10.1101/gr.6.2.132 PG 10 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA UA682 UT WOS:A1996UA68200008 PM 8919692 ER PT J AU Elkahloun, AG Meltzer, PS Guan, XY McNinch, JS Trent, JM deJong, PJ AF Elkahloun, AG Meltzer, PS Guan, XY McNinch, JS Trent, JM deJong, PJ TI Isolation of a cosmid sublibrary for a region of chromosome 12 frequently amplified in human cancers using a complex chromosome microdissection probe SO GENOMICS LA English DT Article ID MALIGNANT-MELANOMA; RAPID GENERATION; HUMAN SARCOMAS; GENE; IDENTIFICATION; AMPLIFICATION; DNA; LIBRARIES; CLONES AB Chromosome-specific cosmid libraries are an extremely useful resource for positional cloning projects. Once a particular region of interest has been identified, it would be of value to have an approach for isolating chromosome band-specific cosmids that could be assembled into a sublibrary for rapid screening. We constructed a region-specific sublibrary of 700 cosmids by screening a chromosome la-specific cosmid library with a complex probe generated by degenerate oligonucleotide-primed PCR of a microdissected homogeneously staining region containing sequences amplified from chromosome 12q13-q15. Based on fluorescence in situ hybridization, approximately 60% of the cosmids in the sublibrary were derived from the microdissected region. To demonstrate further the utility of this sublibrary, a 150-kb contig containing the SAS and CDK4 genes was constructed, as well as several additional contigs between CDK4 and MDM2. This study demonstrates the possibility of utilizing probes generated by microdissection for assembling band-specific sublibraries that are amenable to rapid screening with multiple markers. (C) 1996 Academic Press, Inc. C1 NIH,NCHGR,CANC GENET LAB,BETHESDA,MD 20892. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. ROSWELL PK CANC INST,DEPT HUMAN GENET,BUFFALO,NY 14263. RI Guan, Xin-Yuan/A-3639-2009 OI Guan, Xin-Yuan/0000-0002-4485-6017 NR 20 TC 17 Z9 17 U1 0 U2 0 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0888-7543 J9 GENOMICS JI Genomics PD FEB 1 PY 1996 VL 31 IS 3 BP 343 EP 347 DI 10.1006/geno.1996.0057 PG 5 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA TU592 UT WOS:A1996TU59200010 PM 8838316 ER PT J AU Ingram, BL Conrad, ME Ingle, JC AF Ingram, BL Conrad, ME Ingle, JC TI Stable isotope and salinity systematics in estuarine waters and carbonates: San Francisco Bay SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID PALEOSALINITY; CALIFORNIA AB Salinities, delta D and delta(18)O values of water samples collected bimonthly from two stations in San Francisco Bay estuary during 1991-1993, and along a salinity transect in March of 1992, indicate a linear mixing relation between the isotopic compositions of the waters and their salinities. The salinities and stable isotope compositions of samples from two locations in San Francisco Bay vary in response to changes in freshwater inflow. The data from these locations indicate simple mixtures of Pacific Ocean water (salinity approximate to 33, delta(18)O approximate to 0 to -1 parts per thousand, delta D M 0 to -10 parts per thousand) and Sacramento-San Joaquin River water (salinity approximate to: 0, delta(18)O = -10 to - 12 parts per thousand, SD = -75 to -85 parts per thousand). Preliminary water balance estimates, using isotopic differences between local and upland runoff, suggest that local runoff (including waste water) comprises less than 20% of total freshwater entering the bay. The average delta(18)O values of mussel shells (Mytilus edulis) collected live from eight locations in San Francisco Bay primarily reflect the delta(18)O of the water in which they grew. Shells subsampled along growth bands show that seasonal shifts in salinity and delta(18)O are recorded in the shells. Therefore, the use of stable isotope measurements should be useful in reconstructing pre-instrumental bay salinity and associated freshwater inflow (both annual average values and seasonal variations) to the San Francisco Bay, as well as potentially other estuarine systems. C1 LAWRENCE BERKELEY NATL LAB,BERKELEY CTR ISOTOPE GEOCHEM,DIV EARTH SCI,BERKELEY,CA 94720. STANFORD UNIV,DEPT GEOL & ENVIRONM SCI,STANFORD,CA 94305. RP Ingram, BL (reprint author), UNIV CALIF BERKELEY,DEPT GEOG,BERKELEY,CA 94720, USA. RI Conrad, Mark/G-2767-2010 NR 17 TC 53 Z9 53 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD FEB PY 1996 VL 60 IS 3 BP 455 EP 467 DI 10.1016/0016-7037(95)00398-3 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV457 UT WOS:A1996TV45700007 ER PT J AU Brady, PV Krumhansl, JL Papenguth, HW AF Brady, PV Krumhansl, JL Papenguth, HW TI Surface complexation clues to dolomite growth SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Letter ID CALCITE SURFACE; PRECIPITATION; SORPTION; DOLOMITIZATION; ADSORPTION; MODEL AB Calcium and magnesium adsorb in near-stoichiometric proportions to dolomite over wide ranges in [Ca2+]/[Mg2+] ionic strength, and solution composition pointing to minimal mixing metal cations between the CaCO3 and MgCO3 layer edges exposed at the dolomite surface. Near-neutral pH Mg and Ca adsorb as hydrated ions, or, in sulfate-rich solutions, as metal sulfate complexes. Near-stoichiometric adsorption of Ca and Mg points to dehydration and subsequent carbonation of adsorbed Mg as the likely rate-limiting step for dolomite growth at near-Earth surface conditions. We propose that one path for dolomite growth from low-temperature natural waters is through the initial adsorption of Mg-sulfate complexes onto either (1) growing dolomite crystals or (2) rate-limiting dolomite nucleii. Field relations, as well as homogeneous syntheses at low temperatures (25 degrees C < T < 100 degrees C) support this hypothesis and provide a mechanistic explanation for dolomite growth from sulfate-rich natural waters. RP Brady, PV (reprint author), SANDIA NATL LABS,GEOCHEM RES,MS 750,ALBUQUERQUE,NM 87185, USA. NR 36 TC 64 Z9 66 U1 2 U2 18 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD FEB PY 1996 VL 60 IS 4 BP 727 EP 731 DI 10.1016/0016-7037(95)00436-X PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA TV810 UT WOS:A1996TV81000017 ER PT J AU Tobin, KJ Walker, KR Srinivasan, K Steinhauff, DM AF Tobin, KJ Walker, KR Srinivasan, K Steinhauff, DM TI Suboxic to anoxic diagenesis of platform-marginal ooids and bladed-to-fibrous calcite from the Middle Ordovician Ottosee formation (east Tennessee) SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article ID ORGANIC-MATTER; PORE WATER; SEDIMENTS; CEMENTATION; BRACHIOPODS; OXIDATION; MANGANESE; REDUCTION; SEAWATER; RECORD AB The oolite member of the Ottosee Formation (early Caradoc) has bladed-to-fibrous calcite cement that formed under oxygen-depleted conditions atypical of most abiotic marine precipitates. The sequence of early diagenetic events was as follows: (1) ooid formation, (2) precipitation of rare turbid marine cement, (3) minor dissolution of ooids and initial marine cement, (4) precipitation of translucent bladed-to-fibrous calcite, and (5) stabilization of metastable components, such as ooids anal turbid marine cements. Ooids and turbid marine cements precipitated from oxic fluids. Minor dissolution of ooids and turbid marine cements was associated with aerobic degradation of organic material, which decreased alkalinity through generation of CO2. Translucent bladed-to-fibrous calcite precipitated from suboxic to anoxic marine fluids that were modified by bacterially mediated Mn4+, Fe3+, and SO42- reduction. Translucent bladed-to-fibrous cement was originally low-magnesian calcite and has delta(13)C and delta(18)O values near other Caradoc marine values. Conversely, ooids and turbid marine calcite had a metastable magnesian calcite mineralogy, These components were dramatically altered by stabilization as reflected by negative delta(13)C and delta(18)O ooid values. Mineralogical stabilization of ooids and turbid marine cements mainly post-dated bladed-to-fibrous calcite formation, but some stabilization preceded bladed-to-fibrous calcite cementation, Additionally, this study documents locally variable cathodoluminescence zonation patterns, which are at variance with the cement stratigraphy paradigm of regionally correlatable CL zones. C1 OAK RIDGE NATL LAB,HLTH & SAFETY DIV,OAK RIDGE,TN 37831. RP Tobin, KJ (reprint author), UNIV TENNESSEE,DEPT GEOL SCI,KNOXVILLE,TN 37996, USA. NR 64 TC 7 Z9 7 U1 0 U2 5 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD FEB PY 1996 VL 108 IS 2 BP 155 EP 167 DI 10.1130/0016-7606(1996)108<0155:STADOP>2.3.CO;2 PG 13 WC Geosciences, Multidisciplinary SC Geology GA TT579 UT WOS:A1996TT57900003 ER PT J AU Gilbert, RO Mart, EI Denham, DH Strenge, DL Miley, TB AF Gilbert, RO Mart, EI Denham, DH Strenge, DL Miley, TB TI Uncertainty of historical measurements of I-131 in Hanford-area vegetation SO HEALTH PHYSICS LA English DT Article DE dose assessment; sampling; I-131; radioactivity, airborne AB The Hanford Environmental Dose Reconstruction (HEDR) Project() was conducted to estimate the radiation dose that individuals could have received as a result of emissions to the air and water from Hanford Site operations since 1944, The largest doses were to the human thyroid gland from I-131 released into the atmosphere from Hanford facilities in the 1945-1947 time period, In support of the dose reconstruction effort, a database of historical environmental radioactivity measurements was constructed, This database includes measurements of total radioactivity for vegetation samples collected from 1945-1948 and counted using a Geiger-Mueller (GM) detector system, Because the factors used at that time to convert the GM counts to I-131 activity did not take all parameters into account, and because some parameter values were inaccurate, more accurate conversion factors were developed as part of the HEDR Project. These factors can be used to estimate the actual historical activity levels. This paper summarizes the Monte Carlo uncertainty and sensitivity analysis methods used to assess the uncertainty of the newly reconstructed historical vegetation I-131 activities and to identify the parameters that contributed the most uncertainty to these reconstructed activities. Based on the study of two vegetation (sagebrush) samples collected in the mid-1940's, it appears that the true I-131 activity of the historical vegetation samples should be within a factor of three of the reconstructed activity, Also, the uncertainty in the parameter I-cf (the fraction of the background-corrected GM measurement of a vegetation sample that resulted from I-131) was found to contribute the most uncertainty to the reconstructed I-131 activities when the uncertainty in I-cf was large. RP Gilbert, RO (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. FU NIDCD NIH HHS [200-92-0503 (CDC)/18629] NR 30 TC 2 Z9 3 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD FEB PY 1996 VL 70 IS 2 BP 160 EP 170 DI 10.1097/00004032-199602000-00002 PG 11 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA TT677 UT WOS:A1996TT67700004 PM 8567282 ER PT J AU Mao, XT Kase, KR Nelson, WR AF Mao, XT Kase, KR Nelson, WR TI Giant dipole resonance neutron yields produced by electrons as a function of target material and thickness SO HEALTH PHYSICS LA English DT Article DE computer calculations; neutron dosimetry; dosimetry, external; nuclear workers ID PHOTONEUTRON CROSS-SECTIONS AB This paper characterizes the functional dependence of the Giant Dipole Resonance neutron yield produced by electrons in terms of the atomic number (Z) and thickness (T) of the target. The yields were calculated by integrating, over the photon energy, the product of the differential photon track length and published photoneutron cross sections. The EGS4 Monte Carlo code and analytical formulas were used to calculate the differential photon track length. In thick targets, the Giant Dipole Resonance neutron yield approaches a saturation value as target thickness T increases to 10 radiation lengths. A formula, 8 x 10(-6) x (Z(1/2) + 0.12 Z(3/2) - 0.001 Z(5/2)) n electron(-1)Mev(-1), developed from EGS4 calculations, estimates thick-target neutron yields for incident electron energies E(0) above 50 MeV. Giant Dipole Resonance neutron yields, calculated by several analytic formulas for the differential photon track length, are compared with EGS4 calculations. Modifications to the analytic formulas are suggested. A scaling function is derived to estimate, from the thick-target formula, neutron yields produced in thin targets. RP Mao, XT (reprint author), STANFORD UNIV, STANFORD LINEAR ACCELERATOR CTR, STANFORD, CA 94309 USA. NR 10 TC 13 Z9 13 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD FEB PY 1996 VL 70 IS 2 BP 207 EP 214 DI 10.1097/00004032-199602000-00008 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA TT677 UT WOS:A1996TT67700010 PM 8567288 ER PT J AU Dudney, CS Wilson, DL Otten, JA Gammage, RB AF Dudney, CS Wilson, DL Otten, JA Gammage, RB TI How to screen for Rn-222 in large buildings SO HEALTH PHYSICS LA English DT Article DE Rn-222, indoor; operational topic; sampling; statistics ID STATES AB Rn-222 measurements have been made in over 10,000 ground-contact rooms in 908 federal buildings. These data were examined statistically to compare parametric distributions that might be useful in the design and execution of future surveys of indoor Rn-222 in large buildings. In 152 of the 365 buildings with the most measurements per building, the lognormal distribution was acceptable. Many other distributions were observed in the other 213 buildings, including bi- and tri-modal distributions. In contrast, when data from entire facilities were examined, the data were usually described by a lognormal distribution. Because of the above observations, we propose that any future surveys of indoor Rn-222 in large buildings be done in two phases, screening and assessment. During the screening phase, all facilities may be surveyed with a comparatively low sampling density, perhaps, one measurement per 465 m(2) (5,000 ft(2)) of floor space. Based on the results presented here, it is expected that statistical analysis of the screening data will reveal any facilities with substantial evidence of a high incidence of rooms with elevated indoor Rn-222 concentrations (e.g., above 150 Bq m(-3)). In the assessment phase, the identified facilities sill be surveyed with a sampling density of one measurement for every ground-contact roam or about one per 84 m(2) (900 ft(2)). Using numerical simulation techniques, we have tested the proposed screening phase protocol against data from sixteen facilities. The results of the simulated screenings support the feasibility of a two-phased approach to the task of identifying facilities having rooms with elevated Rn-222 concentrations. C1 LOCKHEED MARTIN ENERGY SYST, HAZARDOUS WASTE & REMEDIAL ACT PROGRAM, OAK RIDGE, TN 37831 USA. RP Dudney, CS (reprint author), OAK RIDGE NATL LAB, HLTH SCI RES DIV, OAK RIDGE, TN 37831 USA. NR 9 TC 3 Z9 3 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD FEB PY 1996 VL 70 IS 2 BP 250 EP 257 DI 10.1097/00004032-199602000-00014 PG 8 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA TT677 UT WOS:A1996TT67700016 PM 8567294 ER PT J AU Fink, JK Leibowitz, L AF Fink, JK Leibowitz, L TI A consistent assessment of the thermophysical properties of sodium SO HIGH TEMPERATURE AND MATERIALS SCIENCE LA English DT Article DE sodium; thermodynamic properties; vapor pressure; enthalpy; heat capacity; density; thermal expansion; compressibility; surface tension; viscosity; thermal conductivity ID RESISTIVITY AB The data on thermodynamic and transport properties of sodium have been reviewed to obtair thermodynamically consistent equations for the thermodynamic and transport properties of saturated sodium liquid and vapor. This article includes new information not included in previous assessments, such as recently available Russian data and analysis. Properties assessed include: vapor pressure, critical parameters, boiling point,enthalpy, heat capacity, enthalpy of vaporization, density, thermal expansion, adiabatic and isothermal compressibility, speed of sound, surface tension, viscosity, and thermal conductivity. Recommended values and their uncertainties are tabulated as functions of temperature. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. NR 54 TC 9 Z9 9 U1 0 U2 1 PU HUMANA PRESS INC PI TOTOWA PA 999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 SN 1080-1278 J9 HIGH TEMP MAT SCI JI High. Temp. Mat. Sci. PD FEB PY 1996 VL 35 IS 1 BP 65 EP 103 PG 39 WC Materials Science, Multidisciplinary SC Materials Science GA TT135 UT WOS:A1996TT13500006 ER PT J AU Cowan, JH Houde, ED Rose, KA AF Cowan, JH Houde, ED Rose, KA TI Size-dependent vulnerability of marine fish larvae to predation: An individual-based numerical experiment SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article DE predation; larval fish; vulnerability; individual-based model ID INSITU ENCLOSURES; HERRING LARVAE; RECRUITMENT; SURVIVAL; MORTALITY; GROWTH; RATES; MODEL; EGGS; AGE AB Twenty-day simulations of responses by a larval fish cohort were investigated with an individual-based model of predation by ctenophore, medusa, and planktivorous fish predators. Results indicate that the relationship between larval size and vulnerability to predation was generally dome-shaped for invertebrate predators and could be dome-shaped for fish predators if they foraged optimally by size, and depended upon attributes of both predators and larval fish prey. For the predators that did not forage optimally, cohort-specific mortality generally decreased as the mean length of larvae in a cohort increased, but bigger or faster-growing larvae within a cohort were not always most likely to survive. Until larvae grew through a ''window'' of vulnerability and reached a threshold length when susceptibility to the predators decreased more rapidly with larval length than encounter rate increased, mean length or growth rate of surviving larvae on each day was slightly lower, or not different from those that died in most of the simulations. After the threshold length was reached, predators began to catch smaller larvae, which resulted in larger survivors. The time necessary to grow through the window and reach the threshold length depended on growth rate of the larvae, size of the predators, and the variance structure of these parameters. These results indicate that size and growth rate of fish larvae are partially decoupled by the predation process and, ultimately, act differentially to determine cohort survival rate, although both may be most important after larvae have reached the threshold length. In these simulations, the threshold length was reached after a significant portion (56-99%) of total larval mortality had occurred; time to reach the threshold was generally shorter for the faster growing cohorts. Initially, both fast- and slow-growing individuals within a larval cohort differed little in size and, therefore, were nearly equally vulnerable to predation. However, reduced risk of predation occurred when all members of a cohort had reached the threshold length, which suggests that mean growth rate of individuals within a cohort, not their size, is probably the more important parameter affecting cumulative mortality, especially when the rate is high. We propose that characteristics of larval survivors may be more influenced by attributes of the predators to which they were exposed in early life, rather than by their initial status within a cohort with respect to length at hatching and potential growth rate. (C) 1996 International Council for the Exploration of the Sea C1 UNIV MARYLAND,CTR ENVIRONM & ESTUARINE STUDIES,CHESAPEAKE BIOL LAB,SOLOMONS,MD 20688. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. RP Cowan, JH (reprint author), UNIV SO ALABAMA,DEPT MARINE SCI,DAUPHIN ISL SEA LAB,MARINE ENVIRONM SCI CONSORTIUM,POB 369-370,DAUPHIN ISL,AL 36688, USA. RI Houde, Edward/D-8498-2012 NR 58 TC 96 Z9 97 U1 2 U2 28 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON, ENGLAND NW1 7DX SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD FEB PY 1996 VL 53 IS 1 BP 23 EP 37 PG 15 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA TW892 UT WOS:A1996TW89200003 ER PT J AU Lew, JY Trudnowski, DJ AF Lew, JY Trudnowski, DJ TI Vibration control of a micro macro-manipulator system SO IEEE CONTROL SYSTEMS MAGAZINE LA English DT Article; Proceedings Paper CT 1995 IEEE International Conference on Robotics and Automation CY MAY 21-27, 1995 CL NAGOYA, JAPAN SP IEEE, Robot & Automat Soc, Sci Council Japan, Robot Soc Japan, Soc Instrument & Control Engineers, Japan Soc Mech Engineers C1 MONTANA INST TECHNOL, DEPT ENGN SCI, BUTTE, MT USA. RP Lew, JY (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 17 TC 28 Z9 29 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0272-1708 J9 IEEE CONTR SYST MAG JI IEEE Control Syst. Mag. PD FEB PY 1996 VL 16 IS 1 BP 26 EP 31 DI 10.1109/37.482134 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA TU423 UT WOS:A1996TU42300007 ER PT J AU Johnson, WA Koontz, TE Jorgenson, RE AF Johnson, WA Koontz, TE Jorgenson, RE TI Axially incident plane-wave scattering from an impedance sphere with two constant isotropic impedance surfaces SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article ID ELECTROMAGNETIC SCATTERING; FORMULATIONS AB The canonical problem of an axially symmetric, isotropic impedance sphere with two constant impedance surfaces is formulated and solved for the case of a normally incident plane wave. Although the solution involves the truncation of an infinite series and numerical inversion of a linear system, its properties of a rapidly converging truncation process, evaluation of matrix elements in terms of known special functions, and rapid generation of remaining modal coefficients allow for an accurate representation of the fields. This is especially important near the impedance junction where discontinuities in some field components are expected. These properties make this solution an ideal test case for more general scattering codes. RP Johnson, WA (reprint author), SANDIA NATL LABS,ELECTROMAGNET ANAL & TEST DEPT,ALBUQUERQUE,NM 87185, USA. NR 13 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 SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD FEB PY 1996 VL 44 IS 2 BP 227 EP 235 DI 10.1109/8.481652 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA TV808 UT WOS:A1996TV80800014 ER PT J AU Kravitz, SH Word, JC Bauer, TM Seigal, PK Armendariz, MG AF Kravitz, SH Word, JC Bauer, TM Seigal, PK Armendariz, MG TI A passive micromachined device for alignment of arrays of single-mode fibers for hermetic photonic packaging - The CLASP concept SO IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY PART B-ADVANCED PACKAGING LA English DT Article; Proceedings Paper CT LEOS National Meeting CY OCT 31-NOV 03, 1994 CL BOSTON, MA SP IEEE, Lasers & Electro Opt Soc DE micromachines; optical packaging; photonic packaging; optical fiber alignment; hermetic optical packaging; optoelectronic packaging; MEMS AB A micro-machined fiber alignment device, called the capture and locking alignment spring positioner (CLASP) has been fabricated, It uses a nickel leaf spring to passively capture vertical arrays of single-mode fibers with similar to 2 mu m accuracy. RP Kravitz, SH (reprint author), SANDIA NATL LABS, MS 0603, ALBUQUERQUE, NM 87185 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1070-9894 J9 IEEE T COMPON PACK B JI IEEE Trans. Compon. Packag. Manuf. Technol. Part B-Adv. Packag. PD FEB PY 1996 VL 19 IS 1 BP 83 EP 89 DI 10.1109/96.486489 PG 7 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA TW908 UT WOS:A1996TW90800015 ER PT J AU Viskoe, DA Donohoe, GW AF Viskoe, DA Donohoe, GW TI Optimal computed tomography data acquisition techniques and filter selection for detection of small density variations SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article AB Accurately measuring small relative density variations within the interior of an object using computed tomography requires special considerations, Data acquisition techniques and filtering must be optimized as a whole to obtain optimal results. It will be shown that using the filtered back-projection reconstruction algorithm, a combination of oversampling, 360-degree data acquisition, data averaging, and a common reconstruction filter can substantially improve image quality, The effect of each of these techniques on image quality is documented with extensive simulations, Images from reconstructions of data obtained from a computed tomography system will be presented and analyzed to support the results of the simulations. C1 UNIV NEW MEXICO,ALBUQUERQUE,NM 87106. RP Viskoe, DA (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. NR 6 TC 8 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 70 EP 76 DI 10.1109/19.481314 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000012 ER PT J AU Gopalsami, N Bakhtiari, S Raptis, AC Dieckman, SL DeLucia, FC AF Gopalsami, N Bakhtiari, S Raptis, AC Dieckman, SL DeLucia, FC TI Millimeter-wave measurements of molecular spectra with application to environmental monitoring SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article ID WAVELENGTHS AB This paper presents results of mm-wave spectral properties of chemicals in the 225-315 GHz frequency range at ambient atmospheric pressure. The effect of pressure broadening of the spectral lines is determined by both experiments and theoretical simulation, Subsequent to the laboratory measurements, the proof of the principle of the open-path monitoring of airborne chemicals was tested by using a monostatic swept-frequency radar system. C1 OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. RP Gopalsami, N (reprint author), ARGONNE NATL LAB,DIV ENERGY TECHNOL,ARGONNE,IL 60439, USA. NR 13 TC 23 Z9 23 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 225 EP 230 DI 10.1109/19.481338 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000036 ER PT J AU Peng, FZ Lai, JS AF Peng, FZ Lai, JS TI Generalized instantaneous reactive power theory for three-phase power systems SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article ID COMPONENTS; VOLTAGE AB A generalized theory of instantaneous reactive power for three-phase power systems is proposed in this paper, This theory gives a generalized definition of instantaneous reactive power, which is valid for sinusoidal or nonsinusoidal, balanced or unbalanced, three-phase power systems with or without zero-sequence currents and/or voltages, The properties and physical meanings of the newly defined instantaneous reactive power are discussed in detail, A three-phase harmonic distorted power system with zero-sequence components is then used as an example to show reactive power measurement and compensation using the proposed theory. C1 OAK RIDGE NATL LAB,ENGN TECHNOL DIV,OAK RIDGE,TN 37831. RP Peng, FZ (reprint author), UNIV TENNESSEE,DEPT ELECT & COMP ENGN,KNOXVILLE,TN 37996, USA. OI Lai, Jihsheng/0000-0003-2315-8460 NR 5 TC 316 Z9 343 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD FEB PY 1996 VL 45 IS 1 BP 293 EP 297 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA TU610 UT WOS:A1996TU61000048 ER PT J AU Oleynik, G Engelfried, J Mengel, L Moore, C Odell, V Pordes, R Semenchenko, A Slimmer, D Udumula, L Votava, M Prelz, F VanDrunen, E Zioulas, G AF Oleynik, G Engelfried, J Mengel, L Moore, C Odell, V Pordes, R Semenchenko, A Slimmer, D Udumula, L Votava, M Prelz, F VanDrunen, E Zioulas, G TI Fermilab DART run control SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 9th Conference on Real-Time Computer Applications in Nuclear, Particle and Plasma Physics (Real-Time 95) CY MAY 23-26, 1995 CL E LANSING, MI SP Michigan State Univ, Natl Superconducting Cyclotron Lab, IEEE, NPSS, Tech Comm Comp Applicat Nucl & Plasma Sci AB DART is the high speed, Unix based data acquisition system being developed by Fermilab in collaboration with seven High Energy Physics Experiments [1 - 6]. This paper describes DART run control, which has been developed over the past year and is a flexible, distributed, extensible system for the control and monitoring of the data acquisition systems. We discuss the unique and interesting concepts of the run control and some of our experiences in developing it. We also give a brief update and status of the whole DART system. C1 IST NAZL FIS NUCL,I-20133 MILAN,ITALY. UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. UNIV CALIF IRVINE,IRVINE,CA 92717. RP Oleynik, G (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 20 EP 24 DI 10.1109/23.485998 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX791 UT WOS:A1996TX79100005 ER PT J AU Streets, J Meadows, J Moore, C Pordes, R Slimmer, D Vittone, M Stern, E AF Streets, J Meadows, J Moore, C Pordes, R Slimmer, D Vittone, M Stern, E TI Access to CAMAC from VxWorks and UNIX in DART SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 9th Conference on Real-Time Computer Applications in Nuclear, Particle and Plasma Physics (Real-Time 95) CY MAY 23-26, 1995 CL E LANSING, MI SP Michigan State Univ, Natl Superconducting Cyclotron Lab, IEEE, NPSS, Tech Comm Comp Applicat Nucl & Plasma Sci AB As part of the DART Project [1] we have developed a package of software for CAMAC access from UNIX and VxWorks [2] platforms, with support for several hardware interfaces. We report on developments for the CES CBD8210 [3] VME to parallel CAMAC, the Hytec VSD2992 [4] VME to serial CAMAC and Jorway 411S [5] SCSI to parallel and serial CAMAC branch drivers, and give a summary of the timings obtained. C1 COLUMBIA UNIV,NEW YORK,NY. RP Streets, J (reprint author), FERMILAB NATL ACCELERATOR LAB,ONLINE SYST DEPT,POB 500,BATAVIA,IL 60510, USA. NR 12 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 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 52 EP 54 DI 10.1109/23.486003 PN 1 PG 3 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX791 UT WOS:A1996TX79100010 ER PT J AU Angstadt, R Borcherding, F Johnson, ME AF Angstadt, R Borcherding, F Johnson, ME TI Using modern software tools to design, simulate and test a level 1 trigger sub-system for the D zero detector SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 9th Conference on Real-Time Computer Applications in Nuclear, Particle and Plasma Physics (Real-Time 95) CY MAY 23-26, 1995 CL E LANSING, MI SP Michigan State Univ, Natl Superconducting Cyclotron Lab, IEEE, NPSS, Tech Comm Comp Applicat Nucl & Plasma Sci AB This paper describes a system which uses a commercial spreadsheet program and commercial hardware on an IBM PC to develop and test a track finding system for the D Zero Level 1 scintillating fiber trigger. The trigger system resides in a VME crate. This system allows the user to generate test input, write the pattern to the hardware, simulate the results in software, read the hardware result, compare the results and inform the user of any differences. C1 CEFET EN,CBPF,LAFEX,RIO JANEIRO,BRAZIL. RP Angstadt, R (reprint author), FERMILAB NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 10 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 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 61 EP 64 DI 10.1109/23.486005 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX791 UT WOS:A1996TX79100012 ER PT J AU Drigert, MW Cole, JD Reber, EL Young, JM AF Drigert, MW Cole, JD Reber, EL Young, JM TI Report on a field-portable VME-based distributed data acquisition system SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 9th Conference on Real-Time Computer Applications in Nuclear, Particle and Plasma Physics (Real-Time 95) CY MAY 23-26, 1995 CL E LANSING, MI SP Michigan State Univ, Natl Superconducting Cyclotron Lab, IEEE, NPSS, Tech Comm Comp Applicat Nucl & Plasma Sci AB A field portable data acquisition system has been developed around a VMEbus based micro-processor and standard TCP/IP network protocols. The hardware consists of a compact VME crate and a single CAMAC crate containing the signal processing electronics. The component processes of the data acquisition system transfer control and event data over a set of TCP/IP socket connections. The use of network sockets for the interprocess communications allows the data acquisition system to be operated transparently on one workstation or on a number of workstations distributed around a local network. RP Drigert, MW (reprint author), IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. RI Reber, Edward/B-4742-2017 OI Reber, Edward/0000-0001-8959-5570 NR 5 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 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 136 EP 139 DI 10.1109/23.486019 PN 1 PG 4 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX791 UT WOS:A1996TX79100026 ER PT J AU Castoldi, A Gatti, E Rehak, P AF Castoldi, A Gatti, E Rehak, P TI Three-dimensional analytical solution of the Laplace equation suitable for semiconductor detector design SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article AB In this paper we present a method to obtain the three-dimensional (3-D) solution of the Laplace equation in closed form suitable for semiconductor detector design. The method applies to planar geometry cases (microstrip detectors, pixel detectors, drift detectors, etc) with possible mixed boundary conditions on the surfaces of the wafer, The solution inside the detector volume is expressed by a series of elementary functions, The method requires lower CPU time and memory than methods based on 3-D discretization, in particular for the study of 3-D carrier trajectories inside the volume of semiconductor detectors and for inter-electrode capacitance calculations. C1 POLITECN MILAN,I-20133 MILAN,ITALY. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP Castoldi, A (reprint author), UNIV MILAN,DIPARTIMENTO FIS,I-20133 MILAN,ITALY. NR 9 TC 14 Z9 14 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 256 EP 265 DI 10.1109/23.485964 PN 2 PG 10 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX792 UT WOS:A1996TX79200002 ER PT J AU Sandler, PH Hailey, CJ Sprehn, G Ziock, KP AF Sandler, PH Hailey, CJ Sprehn, G Ziock, KP TI GRABIT: A large-area, broad-bandwidth, gamma-ray imaging spectrometer for astrophysics SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article ID ASTRONOMY; GRANAT; SIGMA AB GRABIT is the gamma-ray bar imaging telescope, a low-energy gamma-ray (60-600 keV) imaging spectrometer that can be extended to a large area at low cost, GRABIT has a gamma-ray position-resolution of 2 mm with an energy resolution typical of alkali-halide detectors (18% at 60 keV), The complete coded-aperture telescope will have are-minute angular resolution over a large field of view. In addition, the good energy and angular resolutions are obtained over the full bandwidth of the instrument. RP Sandler, PH (reprint author), LAWRENCE LIVERMORE NATL LAB,EXPTL ASTROPHYS LAB,LIVERMORE,CA 94550, USA. NR 10 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD FEB PY 1996 VL 43 IS 1 BP 278 EP 282 DI 10.1109/23.485966 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA TX792 UT WOS:A1996TX79200004 ER PT J AU Coppa, GGM Dellapiana, G Lapenta, G AF Coppa, GGM Dellapiana, G Lapenta, G TI Kinetic simulation of bounded plasmas with the BLOB method SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB In the industrial applications of plasmas, the interaction of charged particles with the surfaces of the reactor chamber is extremely important. Considerable effort is being devoted to study the formation and the properties of the sheath near confining structures or around solid objects immersed in a plasma. In this paper, results obtained by using the BLOB method to simulate collisionless sheaths are presented. The BLOB method is based on the particle-in-cell (PIG) approach, but uses particles with additional degrees of freedom to describe their size and shape. C1 LOS ALAMOS NATL LAB, DIV THEORET, LOS ALAMOS, NM 87545 USA. RP Coppa, GGM (reprint author), POLITECN TORINO, DIPARTIMENTO ENERGET, I-10129 TURIN, ITALY. OI Coppa, Gianni/0000-0002-1003-914X; Lapenta, Giovanni/0000-0002-3123-4024 NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 12 EP 13 DI 10.1109/27.491666 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800005 ER PT J AU DaSilva, LB Cauble, R Barbee, TW Celliers, P Ciarlo, D Libby, S London, RA Matthews, D Mrowka, S Moreno, JC Ress, D Trebes, JE Wan, AS Weber, F AF DaSilva, LB Cauble, R Barbee, TW Celliers, P Ciarlo, D Libby, S London, RA Matthews, D Mrowka, S Moreno, JC Ress, D Trebes, JE Wan, AS Weber, F TI Two-dimensional interferogram of an exploding selenium foil using a soft X-ray laser interferometer SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB We have developed a soft X-ray interferometer capable of probing large high-density plasmas with micron spatial resolutions. A neon-like yttrium X-ray laser operating at 155 Angstrom was combined with the Mach-Zehnder interferometer to obtain electron density profiles of a laser-produced exploding selenium foil plasma. The plasma was produced with one Nova laser beam using a 120-mu m line focus, the same conditions used to create a selenium X-ray laser. The interferogram of the selenium plasma was obtained from an end-on perspective. RP DaSilva, LB (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 5 TC 1 Z9 1 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 31 EP 32 DI 10.1109/27.491676 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800015 ER PT J AU Zerkle, DK Sappey, AD AF Zerkle, DK Sappey, AD TI Time-resolved PLIF imaging of Cu in a laser-ablated copper plasma plume SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Planar laser-induced fluorescence (PLIF) has been used to determine the relative number density of ground state topper atoms in laser-ablated plasma plumes. An ablation laser power flux of similar to 1.5 GW/cm(2) is applied to a solid copper target in a background gas, producing a plasma plume suitable for studying homogeneous copper vapor condensation, Density is measured at postablation time delays ranging from 5 mu s to 10 ms with 1-100 torr of either argon or helium as the background gas. Planar laser-induced fluorescence images are used to spatially resolve the relative density within the plume. The decrease in density is due to the homogeneous condensation of copper vapor to form particulate. RP Zerkle, DK (reprint author), LOS ALAMOS NATL LAB,CHEM SCI & TECHNOL DIV,POB 1663,LOS ALAMOS,NM 87545, USA. NR 2 TC 6 Z9 6 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 37 EP 38 DI 10.1109/27.491679 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800018 ER PT J AU Multari, RA Cremers, DA AF Multari, RA Cremers, DA TI A time-resolved imaging study of Cr (I) emissions from a laser plasma formed on a sample at nonnormal incidence SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB The effect of sample orientation on atomic emission in laser-induced breakdown spectroscopy (LIBS) was studied using time-resolved imaging and spectroscopy. The purpose of this work was to determine the effect of sampling geometry on the analytical performance of the LIBS measurement. The results obtained indicate that atoms are ejected perpendicular to the sample surface independent of the angle-of-incidence of the laser pulse. This result is consistent with previous work by others, In addition, it was found that the observed LIBS atomic emission intensities were maximum for normal laser pulse incidence, reached a minimum at 50 degrees angle-of-incidence, and then increased as the sample was rotated to higher angles-of-incidence. RP Multari, RA (reprint author), LOS ALAMOS NATL LAB,GRP CST1,POB 1663,LOS ALAMOS,NM 87545, USA. NR 3 TC 15 Z9 15 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 39 EP 40 DI 10.1109/27.491680 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800019 ER PT J AU Cameron, SM Tracy, MD Camacho, JF AF Cameron, SM Tracy, MD Camacho, JF TI Electron density and temperature contour plots from a laser-produced plasma using collective ultraviolet Thomson scattering SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Temporally integrated ultraviolet collective Thomson scattering measurements were performed with frequency-quadrupled Nd:YAG laser radiation on an underdense long-scalelength aluminum plasma (n(c) - 10(21) cm(-3), Z approximate to 7, T-e approximate to T; greater than or equal to 50 eV, L greater than or equal to 100 mu m). The plasma was preformed by an Nd:YAG fundamental beam (1.06 mu m) with focusable intensities of 10(11) W/cm(2). Color images of two-dimensional (2-D) spatially resolved (30 mu m) electron density and electron temperature were obtained, These are the shortest wavelength Thomson scattering measurements on a plasma to date. C1 XEROX CORP,WEBSTER,NY 14580. UNIV CALIF DAVIS,DEPT APPL SCI,LIVERMORE,CA 94551. LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551. RP Cameron, SM (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 9 TC 15 Z9 15 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 45 EP 46 DI 10.1109/27.491683 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800022 ER PT J AU Olson, JC Davis, HA Waganaar, WJ AF Olson, JC Davis, HA Waganaar, WJ TI Measurement and modeling of intense ion beam target heating SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Intense ion beam heating of targets has been assessed as a function of the orientation of the target with respect to the beam. A Monte Carlo code has been used to determine the relative energy deposited per unit mass in targets normal to and at 45 degrees to the beam axis. Assumptions about the distribution of ion trajectories used in the calculations are checked by comparison with thermal images of targets exposed to the beam. Peak energy deposition per unit mass is found to be comparable for both target orientations. RP Olson, JC (reprint author), LOS ALAMOS NATL LAB,LOS ALAMOS,NM 87545, USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 65 EP 66 DI 10.1109/27.491693 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800032 ER PT J AU Anders, A Anders, S Juttner, B Luck, H AF Anders, A Anders, S Juttner, B Luck, H TI High-resolution imaging of vacuum arc cathode spots SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Imaging differential laser absorption spectroscopy was used to map the electron density distribution of vacuum are cathode spots, The temporal resolution was determined by the sequence of laser pulses (pulses of 0.4-ns duration, with 3-ns separation), The spatial resolution was limited by diffraction (better than 5 mu m). Fragments of cathode spots have been detected, and the following garameters could be derived: current density on the order of 10(12) A/m(2), plasma density greater than 3-6 x 10(26) m(-3), fragment size 5-10 mu m and smaller, current per fragment 20-40 A (for copper electrodes and are current 50-150 A), and the lifetime of dense plasma on the order of a few nanoseconds. C1 MAX PLANCK INST PLASMA PHYS,BEREICH BERLIN,D-10117 BERLIN,GERMANY. UNIV HANNOVER,INST PLASMAPHYS,W-3000 HANNOVER,GERMANY. RP Anders, A (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. RI Lueck, Harald/F-7100-2011; Anders, Andre/B-8580-2009; Raoux, Simone/G-3920-2016 OI Lueck, Harald/0000-0001-9350-4846; Anders, Andre/0000-0002-5313-6505; NR 4 TC 11 Z9 11 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 69 EP 70 DI 10.1109/27.491695 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800034 ER PT J AU Buss, RJ Ho, P AF Buss, RJ Ho, P TI Two-dimensional imaging of laser-induced fluorescence: OH in a plasma-generated molecular beam scattering from a silicon surface SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article ID DEPOSITING FILM; REACTIVITY; NITRIDE AB Two-dimensional (2-D) imaging is a significant improvement to the IRIS (imaging of radicals interacting with surfaces) technique for measuring the reactivity of plasma-generated radicals at surfaces. Several interesting phenomena resulting from the effects of saturation of the optical transition and of molecular translation during the radiative lifetime of OH have now been observed directly. RP Buss, RJ (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 5 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 79 EP 80 DI 10.1109/27.491700 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800039 ER PT J AU Wurden, GA Whiteson, DO AF Wurden, GA Whiteson, DO TI High-speed plasma imaging: A lightning bolt SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Using a gated intensified digital Kodak Ektapro camera system, we captured a lightning bolt at 1000 frames per second, with 100-mu s exposure time on each consecutive frame. As a thunder storm approached while darkness descended (7:50 pm) on July 21, 1994, we photographed lightning bolts with an f22 105-mm lens and 100% gain on the intensified camera. This 15-frame sequence shows a cloud to ground stroke at a distance of about 1.5 km, which has a series of stepped leaders propagating downwards, followed by the upward-propagating main return stroke. RP Wurden, GA (reprint author), LOS ALAMOS NATL LAB,POB 1663,LOS ALAMOS,NM 87545, USA. RI Wurden, Glen/A-1921-2017 OI Wurden, Glen/0000-0003-2991-1484 NR 3 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 83 EP 84 DI 10.1109/27.491702 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800041 ER PT J AU Coogan, JJ Sappey, AD AF Coogan, JJ Sappey, AD TI Distribution of OH within silent discharge plasma reactors SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Barrier discharges in humid air generate large quantities of OH and are well suited for the treatment of gas-based pollutants, In order to understand and optimize the formation and utilization of OH, we have imaged the spatial and temporal distribution of the OH radical with resolution of 40 mu m and 100 ns. Using a flowing mix of Ar/O-2/H2O (78.5/20/1.5), we have found that OH exists only within the 85-mu m radius channel formed by the transient microdischarge. At modest power densities of 0.1 W/cm(2), over 10(6)/cm(2)/s of these small filaments quickly fill the entire reactor volume. RP Coogan, JJ (reprint author), LOS ALAMOS NATL LAB,DEPT CHEM SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 5 TC 27 Z9 28 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 91 EP 92 DI 10.1109/27.491706 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800045 ER PT J AU Hareland, WA Buss, RJ Brown, DA Collins, SM AF Hareland, WA Buss, RJ Brown, DA Collins, SM TI Monochromatic imaging of scattered laser light from in situ generated particles in plasmas SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Spatially resolved images of particle distributions are measured in steady-state plasmas in a GEC (gaseous electronics conference) plasma reactor, Images are obtained by monochromatic imaging of scattered laser light using a microchannel plate (MCP) image intensifier and a high-speed video camera. The observed distributions of particulates generated by adding small quantities of CHF3 to an argon plasma are extremely complex and diverse, The patterns observed are temporally varying, and rarely as simple as domes and rings observed in other reactors, The forces acting on the particles are sufficiently complex that reproducing specific spatial patterns by controlling processing parameters is often impossible. C1 UNIV ARIZONA,TUCSON,AZ 85721. RP Hareland, WA (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 7 TC 1 Z9 1 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 103 EP 104 DI 10.1109/27.491733 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800051 ER PT J AU Lapenta, G Brackbill, JU AF Lapenta, G Brackbill, JU TI Immersed boundary method for plasma simulation in complex geometries SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB The immersed boundary method is a powerful tool for plasma simulation in complex geometries. In this paper, a brief description of the method is provided and results from a paradigmatic simulation are reported, An advanced color graphics interface, based on an advanced visual system (AVS), is used to highlight the relevant aspects of the simulation. RP Lapenta, G (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. OI Lapenta, Giovanni/0000-0002-3123-4024 NR 3 TC 8 Z9 8 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 105 EP 106 DI 10.1109/27.491734 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800052 ER PT J AU Hareland, WA Buss, RJ AF Hareland, WA Buss, RJ TI Distribution of excited species in plasmas by monochromatic imaging SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Spatial maps of individual argon atomic emissions are measured in the GEC (gaseous electronic conference) reference reactor by monochromatic imaging, The plasma discharge is viewed through a grating monochromator, and the images are recorded with an intensified charge-coupled device (CCD) array detector. Each atomic emission has a unique spatial profile that is related to the spatial energy distribution in the plasma. RP Hareland, WA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 5 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 117 EP 118 DI 10.1109/27.491740 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800058 ER PT J AU Hebner, GA Greenberg, KE AF Hebner, GA Greenberg, KE TI Spatial profiles of metastable densities and electric field strengths in parallel-plate radio frequency discharges SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Metastable densities and sheath electric field strengths have been measured in 13.56-MHz parallel-plate helium discharges. Absorption spectroscopy was used to measure the helium singlet metastable density throughout the volume of the discharge. The singlet metastable density appeared to be depleted near the center of the discharge region, particularly at higher powers. Spatially and temporally resolved sheath electric field strength was determined from laser-induced fluorescence measurements of the Stark structure of the n = 11 singlet Rydberg manifold, Two-dimensional (2-D) maps of the electric field strength indicate that the field is uniform across a large fraction of the electrode diameter. C1 UNIV NEW MEXICO,DEPT CHEM & NUCL ENGN,ALBUQUERQUE,NM 87131. RP Hebner, GA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 4 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 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 121 EP 122 DI 10.1109/27.491742 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800060 ER PT J AU Vitello, P Bardsley, JN DiPeso, G Parker, GJ AF Vitello, P Bardsley, JN DiPeso, G Parker, GJ TI Modeling an inductively coupled plasma reactor with chlorine chemistry SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Inductively coupled plasma reactors are now one of the most important of the high-density plasma processing tools that have been developed in recent Sears. We present results from a two-dimensional (2-D) time-dependent fluid model of a chlorine plasma discharge, The steady-state values for the plasma potential, and the ion fluxes for Cl-2(+) and Cl- are shown for a simulation of the Lawrence Livermore National Laboratory (LLNL) large area inductively coupled reactor experiment, The counter streaming of positive and negative ions is evident, The flux of Cl-2(+) is highly uniform over the lower surface of the reactor. RP Vitello, P (reprint author), LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 5 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 123 EP 124 DI 10.1109/27.491743 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800061 ER PT J AU Johannes, J Bartel, TJ Economou, DJ Lymberopoulos, DP Wise, RS AF Johannes, J Bartel, TJ Economou, DJ Lymberopoulos, DP Wise, RS TI Simulation images from a low-pressure chlorine plasma reactor using DSMC SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Modeling of high-density chemically reacting plasmas at low pressures (<10 mtorr) is of interest to the microelectronics industry for improving tool and process designs, High-density plasma simulations were performed using a fluids code to predict electron behavior, coupled to a Direct Simulation Monte Carlo (DSMC) program for neutral and ion transport, Images presented are for a chlorine plasma simulation at 10 mtorr and include the temperature difference between neutral species, depicting the nonthermal equilibrium nature of the plasma, and angular and energy distributions of ions and neutrals to the wafer surface. C1 UNIV HOUSTON,HOUSTON,TX 77204. RP Johannes, J (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 4 TC 1 Z9 1 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 127 EP 128 DI 10.1109/27.491745 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800063 ER PT J AU Lymberopoulos, DP Wise, RS Economou, DJ Bartel, TJ AF Lymberopoulos, DP Wise, RS Economou, DJ Bartel, TJ TI Ion density and temperature distributions in an inductively coupled high-plasma density reactor SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB In a low-pressure plasma, the ion temperature T-i is comparable to the gas temperature T-g in regions of weak electric fields, but T-i can be more than an order of magnitude higher than T-g near the plasma sheath. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Lymberopoulos, DP (reprint author), UNIV HOUSTON,DEPT CHEM ENGN,PLASMA PROC LAB,HOUSTON,TX 77204, USA. NR 4 TC 3 Z9 3 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 129 EP 130 DI 10.1109/27.491746 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800064 ER PT J AU Economou, DJ Bartel, TJ AF Economou, DJ Bartel, TJ TI Direct simulation Monte Carlo (DSMC) of rarefied gas flow during etching of large diameter (300-mm) wafers SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article AB Strong density gradients of a gas species can be sustained even at very low pressures when the reaction probability of that species is high, Under these conditions, inlet gas arrangements are very important to reaction uniformity. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP Economou, DJ (reprint author), UNIV HOUSTON,DEPT CHEM ENGN,PLASMA PROC LAB,HOUSTON,TX 77204, USA. NR 3 TC 7 Z9 8 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1996 VL 24 IS 1 BP 131 EP 132 DI 10.1109/27.491747 PG 2 WC Physics, Fluids & Plasmas SC Physics GA UE718 UT WOS:A1996UE71800065 ER PT J AU Brost, RC Goldberg, KY AF Brost, RC Goldberg, KY TI A complete algorithm for designing planar fixtures using modular components SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article AB Commercially available modular fixturing systems typically include a lattice of holes with precise spacing and an assortment of precision locating and clamping modules that can be rigidly attached to the lattice. Currently, machinists manually design a suitable arrangement of these modules to hold a given part. This requires expertise and can delay production. Futhermore, a machinist may in many cases settle upon an arrangement that is not optimal for a given machining operation. In this paper we present an implemented algorithm that accepts a polygonal description of the part silhouette, and efficiently constructs the set of all feasible fixture designs that kinematically constrain the part in the plane. Each fixture is comprised of three locators rigidly attached to the lattice and one sliding clamp, and constrains the part without relying on friction. The algorithm is based on an efficient enumeration of admissible designs that exploits part geometry and a graphical force analysis. The algorithm run time is linear in the number of designs found, which is bounded by a polynomial in the number of part edges and the part's maximal diameter in lattice units. Our review of the literature suggests that this is the first fixturing algorithm that is complete in the sense that it is guaranteed to find all admissible fixture designs for an arbitrary polygonal part silhouette and to identify the optimal fixture relative to an arbitrary quality metric. The algorithm does not consider out-of-plane forces or motions; however, we view this planar result as an essential component of a larger algorithm that solves the 3-D fixture design problem by treating the planar and out-of-plane constraint problems separately. This approach is analogous to the widely used 3-2-1 fixture design heuristic, and appears to be applicable to a broad class of man-made parts. C1 UNIV SO CALIF, LOS ANGELES, CA 90089 USA. RP SANDIA NATL LABS, POB 5800, ALBUQUERQUE, NM 87185 USA. OI Goldberg, Ken/0000-0001-6747-9499 NR 43 TC 106 Z9 111 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD FEB PY 1996 VL 12 IS 1 BP 31 EP 46 DI 10.1109/70.481749 PG 16 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA TY461 UT WOS:A1996TY46100004 ER PT J AU Goldstein, B Wofsy, C AF Goldstein, B Wofsy, C TI Why is it so hard to dissociate multivalent antigens from cell-surface antibodies? SO IMMUNOLOGY TODAY LA English DT Article ID RBL-2H3 MAST-CELLS; BASOPHILIC LEUKEMIA-CELLS; IGE-RECEPTOR COMPLEXES; HIGH-AFFINITY RECEPTOR; IMMUNOGLOBULIN-E; CROSS-LINKING; DESENSITIZATION; LIGAND; AGGREGATION; TRANSITION AB It is often difficult to induce dissociation of multivalent antigens that are bound to cells by surface-associated immunoglobulin (sIg), even when high concentrations of monovalent hapten are used to fill all free binding sites. Here, Byron Goldstein and Carla Wofsy discuss the evidence that this appears to be due to a cellular and propose that a receptor-desensitization process is responsible for the transition of multivalent antigens to a dissociation-resistant state. C1 UNIV NEW MEXICO,DEPT MATH & STAT,ALBUQUERQUE,NM 87131. RP Goldstein, B (reprint author), LOS ALAMOS NATL LAB,DIV THEORET,THEORET BIOL & BIOPHYS GRP,LOS ALAMOS,NM 87545, USA. FU NIGMS NIH HHS [GM35556] NR 22 TC 26 Z9 26 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0167-5699 J9 IMMUNOL TODAY JI Immunol. Today PD FEB PY 1996 VL 17 IS 2 BP 77 EP 80 DI 10.1016/0167-5699(96)80583-4 PG 4 WC Immunology SC Immunology GA TU506 UT WOS:A1996TU50600008 PM 8808054 ER PT J AU Conley, AJ AF Conley, AJ TI Centrifugal destabilization and restabilization of plane shear flows SO INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS LA English DT Article AB The flow of an incompressible viscous fluid between parallel plates becomes unstable when the plates are tumbled. As the tumbling rate increases, the flow restabilizes. This phenomenon is elucidated by path-following techniques. The solution of the Navier-Stokes equations is approximated by spectral techniques. The linear stability of these solutions is studied. RP Conley, AJ (reprint author), ARGONNE NATL LAB,DIV MATH & COMP SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0218-1274 J9 INT J BIFURCAT CHAOS JI Int. J. Bifurcation Chaos PD FEB PY 1996 VL 6 IS 2 BP 409 EP 413 DI 10.1142/S0218127496000151 PG 5 WC Mathematics, Interdisciplinary Applications; Multidisciplinary Sciences SC Mathematics; Science & Technology - Other Topics GA UK686 UT WOS:A1996UK68600014 ER EF