FN Thomson Reuters Web of Science™ VR 1.0 PT J AU BOWMAN, DR PEASLEE, GF COLONNA, N CHARITY, RJ MCMAHAN, MA DELIS, D HAN, H JING, K WOZNIAK, GJ MORETTO, LG KEHOE, WL LIBBY, B MIGNEREY, AC MORONI, A ANGIUS, S IORI, I PANTALEO, A GUARINO, G AF BOWMAN, DR PEASLEE, GF COLONNA, N CHARITY, RJ MCMAHAN, MA DELIS, D HAN, H JING, K WOZNIAK, GJ MORETTO, LG KEHOE, WL LIBBY, B MIGNEREY, AC MORONI, A ANGIUS, S IORI, I PANTALEO, A GUARINO, G TI EQUILIBRIUM AND NONEQUILIBRIUM COMPLEX FRAGMENT EMISSION IN 50-100 MEV/U LA-139+C-12 REACTIONS SO NUCLEAR PHYSICS A LA English DT Article ID INTERMEDIATE-MASS FRAGMENTS; NUCLEUS-NUCLEUS COLLISIONS; LINEAR MOMENTUM-TRANSFER; C-12 INDUCED REACTIONS; HEAVY-ION REACTIONS; COMPOUND-NUCLEUS; INELASTIC-COLLISIONS; INCOMPLETE FUSION; MACROSCOPIC MODEL; DECAY AB Complex fragment emission (Z > 2) has been studied in the reactions of 50, 80, and 100 MeV/u La-139 + C-12. Charge, angle, and energy distributions were measured inclusively and in coincidence with other complex fragments, and were used to extract source rapidities, velocity distributions, and cross sections. The binary signature of the coincidence events and the sharpness of the velocity distributions illustrate the primarily 2-body nature of these reactions. Calculations based on statistical compound nucleus decay have been compared with the experimental data. The emission velocities, angular distributions, and absolute cross sections of fragments of 20 less-than-or-equal-to Z less-than-or-equal-to 35 at 50 MeV/u, 19 less-than-or-equal-to Z less-than-or-equal-to 28 at 80 MeV/u, and 17 less-than-or-equal-to Z less-than-or-equal-to 21 at 100 MeV/u are consistent with the binary decay of compound nuclei formed in incomplete fusion reactions in which the La-139 projectile picks up about one-half of the C-12 target. At 80 and 100 MeV/u, statistical model calculations are also able to reproduce the isotropic portion of the cross section for lighter and heavier fragments. However, a significant fraction of the total cross section for these fragments is due to non-equilibrium emission. Although the emission process is still mainly binary, and the relative velocity between the fragments is determined by their mutual Coulomb repulsion, the anisotropic angular distributions and the magnitudes of the absolute yields are incompatible with standard compound-nucleus statistical decay. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. UNIV MILAN,DEPT PHYS,I-20133 MILAN,ITALY. UNIV MARYLAND,DEPT CHEM,COLLEGE PK,MD 20742. NATL INST NUCL PHYS,MILAN,ITALY. IST NAZL FIS NUCL,I-70126 BARI,ITALY. RI Mignerey, Alice/D-6623-2011 NR 69 TC 25 Z9 25 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 11 PY 1991 VL 523 IS 2 BP 386 EP 425 DI 10.1016/0375-9474(91)90010-4 PG 40 WC Physics, Nuclear SC Physics GA FB250 UT WOS:A1991FB25000010 ER PT J AU SCHROTH, GP GOTTESFELD, JM BRADBURY, EM AF SCHROTH, GP GOTTESFELD, JM BRADBURY, EM TI TFIIIA INDUCED DNA BENDING - EFFECT OF LOW IONIC-STRENGTH ELECTROPHORESIS BUFFER CONDITIONS SO NUCLEIC ACIDS RESEARCH LA English DT Article ID TRANSCRIPTION FACTOR-IIIA; 5S RNA GENE; DIRECTS SPECIFIC INITIATION; INTERNAL CONTROL REGION; XENOPUS-LAEVIS; 5S-RNA GENE; COMPLEX; SEQUENCE; REPLICATION; PROMOTER AB We have used a circular permutation gel shift assay to show that the 5S gene transcription factor, TFIIIA, induces a bend at the internal promoter of the Xenopus oocyte-type 5S gene. The degree of bending is comparable to what we have previously observed for TFIIIA induced bending of the Xenopus somatic-type gene [Schroth, G.P. et al. (1989) Nature 340, 487-488]. In addition, we show that TFIIIA induced DNA bending is dramatically affected by the ionic conditions used during gel electrophoresis. By modifying the conditions of the electrophoresis, we can detect two distinct conformations for the TFIIIA/DNA complex. In very low ionic strength buffers, the degree of DNA bending in the complex is estimated to be about 25 to 30 degrees, whereas in higher ionic strength buffers it is about 60 to 65 degrees. These data explain the apparent discrepancy between our results and the results of another study in which it was claimed that TFIIIA did not 'substantially' bend DNA [Zweib, C. and Brown, R.S. (1990) Nucleic Acid Res. 18, 583-587]. These results also demonstrate that the TFIIIA/DNA complex has a large degree of conformational flexibility. Both DNA bending and conformational flexibility are structural features which may provide a key insight into the function of TFIIIA as a positive transcription factor. C1 MED BIOL INST,LA JOLLA,CA 92037. UNIV CALIF LOS ALAMOS SCI LAB,DIV LIFE SCI,LOS ALAMOS,NM 87545. RP SCHROTH, GP (reprint author), UNIV CALIF DAVIS,SCH MED,DEPT BIOL CHEM,DAVIS,CA 95616, USA. OI Gottesfeld, Joel/0000-0002-4643-5777 FU NIGMS NIH HHS [GM 26453, GM-26901] NR 43 TC 18 Z9 18 U1 0 U2 0 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 11 PY 1991 VL 19 IS 3 BP 511 EP 516 DI 10.1093/nar/19.3.511 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EY712 UT WOS:A1991EY71200013 PM 2011525 ER PT J AU CHENG, S SANCAR, A HEARST, JE AF CHENG, S SANCAR, A HEARST, JE TI RECA-DEPENDENT INCISION OF PSORALEN-CROSS-LINKED DNA BY (A)BC EXCINUCLEASE SO NUCLEIC ACIDS RESEARCH LA English DT Article ID ESCHERICHIA-COLI; CROSS-LINKS; ABC EXCINUCLEASE; ACTION MECHANISM; POLYMERASE-I; REPAIR; EXCISION; PURIFICATION; SUBSTRATE; ADDUCTS AB Previous work to elucidate the mechanism of crosslink repair by (A)BC excinuclease has shown that a psoralen-crosslinked duplex is selectively incised in the furan-side strand, while a three-stranded structure is incised in the pyrone-side strand of the crosslink. These observations support a sequential incision and recombination model for the complete error-free repair of a psoralen crosslink. The work presented here extends these findings by demonstrating that in the presence of RecA protein and a homologous DNA oligonucleotide, (A)BC excinuclease is induced to incise the pyrone-side strand of a crosslinked double-stranded plasmid molecule. This finding adds further support to the current model for error-free crosslink repair. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CHEM DYNAM LAB,BERKELEY,CA 94720. UNIV N CAROLINA,DEPT BIOCHEM,CHAPEL HILL,NC 27599. FU NIGMS NIH HHS [GM32833] NR 21 TC 61 Z9 62 U1 0 U2 1 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 11 PY 1991 VL 19 IS 3 BP 657 EP 663 DI 10.1093/nar/19.3.657 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EY712 UT WOS:A1991EY71200034 PM 2011535 ER PT J AU MURAKAMI, M CARRERAS, BA BAYLOR, LR BELL, GL BIGELOW, TS ENGLAND, AC GLOWIENKA, JC HOWE, HC JERNIGAN, TC LEE, DK LYNCH, VE MA, CH RASMUSSEN, DA TOLLIVER, JS WADE, MR WILGEN, JB WING, WR AF MURAKAMI, M CARRERAS, BA BAYLOR, LR BELL, GL BIGELOW, TS ENGLAND, AC GLOWIENKA, JC HOWE, HC JERNIGAN, TC LEE, DK LYNCH, VE MA, CH RASMUSSEN, DA TOLLIVER, JS WADE, MR WILGEN, JB WING, WR TI BOOTSTRAP-CURRENT EXPERIMENTS IN A TOROIDAL PLASMA-CONFINEMENT DEVICE SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARALLEL VISCOSITY; TRANSPORT; STELLARATORS; TOKAMAK; SYSTEMS; REGIME AB The toroidal current observed during electron cyclotron heating in the Advanced Toroidal Facility torsatron is identified as bootstrap current. The observed currents, ranging between +4 and -2 kA, agree well with predictions of neoclassical theory in magnitude and parametric dependence, as determined by systematic scans of quadrupole (shaping) and dipole (magnetic axis shift) moments of the poloidal magnetic field. It has been shown that the bootstrap current in a stellarator can be externally controlled, and zero-current operation can be achieved. C1 MARTIN MARIETTA ENERGY SYST INC,DIV COMP & TELECOMMUN,OAK RIDGE,TN 37831. MARTIN MARIETTA ENERGY SYST INC,DIV ENGN,OAK RIDGE,TN 37831. GEORGIA INST TECHNOL,ATLANTA,GA 30332. RP MURAKAMI, M (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. RI Lynch, Vickie/J-4647-2012 OI Lynch, Vickie/0000-0002-5836-7636 NR 20 TC 40 Z9 40 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 11 PY 1991 VL 66 IS 6 BP 707 EP 710 DI 10.1103/PhysRevLett.66.707 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300008 ER PT J AU TUSZEWSKI, M BARNES, DC CHRIEN, RE COBB, JW REJ, DJ SIEMON, RE TAGGART, DP WRIGHT, BL AF TUSZEWSKI, M BARNES, DC CHRIEN, RE COBB, JW REJ, DJ SIEMON, RE TAGGART, DP WRIGHT, BL TI OBSERVATIONS OF TILT INSTABILITIES IN FIELD-REVERSED CONFIGURATIONS OF A CONFINED PLASMA SO PHYSICAL REVIEW LETTERS LA English DT Article ID STABILITY AB We report the first consistent observations of internal tilt instabilities in field-reversed configurations. Detailed comparisons with numerical calculations establish that data from an array of external magnetic probes are signatures of these destructive plasma instabilities. As suggested by finite-Larmor-radius theory, field-reversed configurations appear grossly stable when s/e [(average number of ion gyroradii)/(separatrix elongation)] is less than 0.2-0.3 and show MHD-like tilt instabilities when s/e approximately 1. RP TUSZEWSKI, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 18 TC 38 Z9 38 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 11 PY 1991 VL 66 IS 6 BP 711 EP 714 DI 10.1103/PhysRevLett.66.711 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300009 ER PT J AU JESSON, DE PENNYCOOK, SJ BARIBEAU, JM AF JESSON, DE PENNYCOOK, SJ BARIBEAU, JM TI DIRECT IMAGING OF INTERFACIAL ORDERING IN ULTRATHIN (SIMGEN)P SUPERLATTICES SO PHYSICAL REVIEW LETTERS LA English DT Article ID SI-GE SUPERLATTICES; OPTICAL-TRANSITIONS; HETEROEPITAXY; GERMANIUM; STABILITY; SILICON; ALLOYS; GROWTH; LAYER AB We present the first atomic-resolution images of interfacial ordering occurring in ultrathin (Si(m)Ge(n))p superlattices. The observed asymmetric interfacial abruptness is associated with several distinct ordered configurations, which differ from phases considered previously. This is explained by a novel Ge-atom pump mechanism which is chemically driven, and takes place principally at the rebonded edge configuration during type-S(B) step propagation, leading to lateral (2 x 2) compositional ordering. C1 NATL RES COUNCIL CANADA,INST MICROSTRUCT SCI,OTTAWA K1A 0R6,ONTARIO,CANADA. RP JESSON, DE (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. OI Jesson, David/0000-0003-0897-1445 NR 20 TC 148 Z9 149 U1 3 U2 10 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 11 PY 1991 VL 66 IS 6 BP 750 EP 753 DI 10.1103/PhysRevLett.66.750 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300019 ER PT J AU PINSKI, FJ GINATEMPO, B JOHNSON, DD STAUNTON, JB STOCKS, GM GYORFFY, BL AF PINSKI, FJ GINATEMPO, B JOHNSON, DD STAUNTON, JB STOCKS, GM GYORFFY, BL TI ORIGINS OF COMPOSITIONAL ORDER IN NIPT ALLOYS SO PHYSICAL REVIEW LETTERS LA English DT Article ID COHERENT-POTENTIAL APPROXIMATION AB We investigate the cause of compositional ordering in fcc Ni0.50Pt0.50 on the basis of a first-principles theory of electronic structure and finite-temperature concentration fluctuations. We treat the size effect, electronegativity, and band filling on an equal footing and find that the first of these dominates, leading to L 1(0) ordering in agreement with experiment. An electronic origin is given for the metallurgical "rule of thumb" that alloys comprised of big atoms and little atoms tend to order into simple structures. C1 UNIV MESSINA,IST FIS TEOR,I-98166 MESSINA,ITALY. UNIV MESSINA,CTR INTERUNIV STRUTTURA MAT,UNITA GRP NAZL STRUTTURA MAT,I-98166 MESSINA,ITALY. SANDIA NATL LABS,DIV THEORET,LIVERMORE,CA 94550. UNIV WARWICK,DEPT PHYS,COVENTRY CV4 7AL,W MIDLANDS,ENGLAND. OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. UNIV BRISTOL,HH WILLS PHYS LAB,BRISTOL BS8 1TL,AVON,ENGLAND. RP PINSKI, FJ (reprint author), UNIV CINCINNATI,DEPT PHYS,CINCINNATI,OH 45212, USA. RI Stocks, George Malcollm/Q-1251-2016; OI Stocks, George Malcollm/0000-0002-9013-260X; Johnson, Duane/0000-0003-0794-7283 NR 25 TC 63 Z9 63 U1 2 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 11 PY 1991 VL 66 IS 6 BP 766 EP 769 DI 10.1103/PhysRevLett.66.766 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300023 ER PT J AU HASTINGS, JB SIDDONS, DP VANBURCK, U HOLLATZ, R BERGMANN, U AF HASTINGS, JB SIDDONS, DP VANBURCK, U HOLLATZ, R BERGMANN, U TI MOSSBAUER-SPECTROSCOPY USING SYNCHROTRON RADIATION SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEAR BRAGG SCATTERING; DIFFRACTION; CRYSTAL; PULSES AB Delayed coherent nuclear forward scattering of synchrotron radiation by polycrystalline Fe foils (both isotopically enriched and naturally abundant) has been measured. Quantum beats were observed in the time spectra. With the chosen experimental conditions these can only arise from coherent scattering. The 5-meV bandwidth provided by a special silicon crystal monochromator obviates the need for a nuclear resonant filter. This direct approach offers the possibility of performing a wide range of Mossbauer spectroscopy experiments using synchrotron radiation. RP HASTINGS, JB (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 24 TC 190 Z9 192 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 11 PY 1991 VL 66 IS 6 BP 770 EP 773 DI 10.1103/PhysRevLett.66.770 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300024 ER PT J AU HAYDEN, SM AEPPLI, G MOOK, H RYTZ, D HUNDLEY, MF FISK, Z AF HAYDEN, SM AEPPLI, G MOOK, H RYTZ, D HUNDLEY, MF FISK, Z TI MAGNETIC FLUCTUATIONS IN LA1.95BA0.05CUO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID LA2CUO4; EXCITATIONS; SPIN AB Neutron-scattering and resistivity experiments on single crystals of La1.95Ba0.05CuO4 are described. On warming to as high as 250 K, the correlation length does not change, and the temperature dependence of the generalized susceptibility chi(Q, omega) is due solely to the temperature dependence of the local response. We show that the associated relaxation rate in the metallic regime is h-GAMMA approximately-equals 1/2 k(B)T, in accord with the marginal-Fermi-liquid hypothesis, and relate our results to nuclear spin-lattice relaxation data. C1 INST MAX VON LAUE PAUL LANGEVIN,F-38042 GRENOBLE,FRANCE. AT&T BELL LABS,MURRAY HILL,NJ 07974. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. SANDOZ OPTOELECTR,CH-4002 BASEL,SWITZERLAND. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RI Hayden, Stephen/F-4162-2011 OI Hayden, Stephen/0000-0002-3209-027X NR 20 TC 136 Z9 136 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 11 PY 1991 VL 66 IS 6 BP 821 EP 824 DI 10.1103/PhysRevLett.66.821 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300037 ER PT J AU WOOD, RF AF WOOD, RF TI SPIN POLARONS, HOLE FILLING, AND HIGH-TC SUPERCONDUCTIVITY IN YBA2CU3O7 AND PRBA2CU3O7 ALLOYS AND LAYERED FILMS SO PHYSICAL REVIEW LETTERS LA English DT Article ID NORMAL-STATE PROPERTIES; LA2-XSRXCUO4 AB Using results from previous work on a spin-polaron model of high-T(c) superconductivity, together with a hole-filling mechanism, excellent agreement with experimental data for T(c) in Y-Ba-Cu-O and Pr-Ba-Cu-O alloys and layered structures is obtained without introducing either pair breaking by the Pr ions or pairing interactions between unit cells. RP WOOD, RF (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 19 TC 68 Z9 68 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 11 PY 1991 VL 66 IS 6 BP 829 EP 832 DI 10.1103/PhysRevLett.66.829 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300039 ER PT J AU EVANS, JW MIESCH, MS AF EVANS, JW MIESCH, MS TI CHARACTERIZING KINETICS NEAR A 1ST-ORDER CATALYTIC POISONING TRANSITION SO PHYSICAL REVIEW LETTERS LA English DT Article ID SURFACE-REACTION MODEL; PHASE-TRANSITIONS; HETEROGENEOUS CATALYSIS; FIELD-THEORY; BEHAVIOR AB We consider the kinetics near a first-order poisoning transition for simple surface reaction models which exclude nonreactive desorption. Elucidation of the development and growth of the reactive steady state from a near-poisoned state is achieved via an "oxidation epidemic" analysis of the evolution of an empty patch embedded in the poisoned phase. Associated critical exponents vary strongly with reaction rate, and reflect slow kinetics. The increase in epidemic survival probability with initial patch size is smooth, and described by additional exponents, rather than indicating a critical size for survival. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS & MATH,AMES,IA 50011. RP EVANS, JW (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011, USA. RI Miesch, Mark/B-1104-2008; OI Miesch, Mark/0000-0003-1976-0811 NR 18 TC 106 Z9 106 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 11 PY 1991 VL 66 IS 6 BP 833 EP 836 DI 10.1103/PhysRevLett.66.833 PG 4 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300040 ER PT J AU NORMAN, MR AF NORMAN, MR TI BCS GAP EQUATIONS IN THE QUANTUM LIMIT SO PHYSICAL REVIEW LETTERS LA English DT Letter RP NORMAN, MR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Norman, Michael/C-3644-2013 NR 4 TC 5 Z9 5 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 11 PY 1991 VL 66 IS 6 BP 842 EP 842 DI 10.1103/PhysRevLett.66.842 PG 1 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300046 ER PT J AU TESANOVIC, Z RASOLT, M XING, L AF TESANOVIC, Z RASOLT, M XING, L TI BCS GAP EQUATIONS IN THE QUANTUM LIMIT - REPLY SO PHYSICAL REVIEW LETTERS LA English DT Letter ID MAGNETIC-FIELD; SUPERCONDUCTIVITY C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP TESANOVIC, Z (reprint author), JOHNS HOPKINS UNIV,DEPT PHYS & ASTRON,BALTIMORE,MD 21218, USA. NR 11 TC 2 Z9 2 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 11 PY 1991 VL 66 IS 6 BP 843 EP 844 DI 10.1103/PhysRevLett.66.843 PG 2 WC Physics, Multidisciplinary SC Physics GA EX923 UT WOS:A1991EX92300047 ER PT J AU ANDER, ME HUGHES, RJ LUTHER, GG AF ANDER, ME HUGHES, RJ LUTHER, GG TI GEOPHYSICAL TESTS OF THE GRAVITATIONAL RED SHIFT AND ETHER DRIFT SO PHYSICS LETTERS A LA English DT Article ID GRAVITY; SPACE; CONSTANT AB A conceptually simple earth-based experiment is proposed for measuring the gravitational red shift to a precision of 5 x 10(-5) and for measuring the ether drift to a precision approaching 1 x 10(-7) by placing synchronous atomic clocks at the top of Mt. Chimborazo in Ecuador, at sea level in Ecuador, at the bottom the Ecuadorian trench, at sea level at the north pole, and at bottom of and at the surface above the Mariana trench. The experiment is designed to measure the decoupled effects of both the gravitational red shift and ether drift components of time dilation. Using present technology, such a measurement would provide a factor of 3.4 increased precision over previous measurements of the gravitational ref shift and would stand alone as a precise test of the isotropy of space, interpreted as ether drift, on a geophysical scale. RP ANDER, ME (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544, USA. NR 29 TC 2 Z9 2 U1 1 U2 2 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 11 PY 1991 VL 152 IS 9 BP 458 EP 462 DI 10.1016/0375-9601(91)90554-L PG 5 WC Physics, Multidisciplinary SC Physics GA EX984 UT WOS:A1991EX98400003 ER PT J AU SAVAGE, MJ MALANEY, RA FULLER, GM AF SAVAGE, MJ MALANEY, RA FULLER, GM TI NEUTRINO OSCILLATIONS AND THE LEPTONIC CHARGE OF THE UNIVERSE SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMOLOGY; ELEMENTARY PARTICLES; NEUTRINOS; NUCLEOSYNTHESIS ID BIG-BANG NUCLEOSYNTHESIS; NUMBER NON-CONSERVATION; STELLAR COLLAPSE; CP-VIOLATION; ASYMMETRY; MATTER; MECHANISM; WIDTH; MASS; Z0 AB The most stringent bounds on the individual lepton numbers of the universe arise from considerations of primordial nucleosynthesis. We consider the effect of resonant neutrino flavor oscillations on these limits. In particular, we include the contributions from neutrino-neutrino forward scattering to the effective mass of each neutrino flavor. We find that there can be significant modifications to the neutrino number densities and energy distributions for each flavor over a large range of neutrino vacuum masses and mixing angles. Modifications to the neutrino distributions occurring prior to the nucleosynthesis epoch can substantially alter the previously derived limits on the lepton number for each flavor and its associated degeneracy parameter. C1 CALTECH,PASADENA,CA 91125. UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY SCI,LIVERMORE,CA 94550. RI Malaney, Robert/F-6588-2012 OI Malaney, Robert/0000-0001-9672-5601 NR 49 TC 40 Z9 40 U1 0 U2 2 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 1991 VL 368 IS 1 BP 1 EP 11 DI 10.1086/169665 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EU508 UT WOS:A1991EU50800001 ER PT J AU AMENDT, P CUDDEFORD, P AF AMENDT, P CUDDEFORD, P TI EXTENDED STELLAR HYDRODYNAMICS FOR GALACTIC DISKS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GALAXIES, INTERNAL MOTIONS; GALAXIES, STRUCTURE; STARS, STELLAR DYNAMICS ID SURFACE MASS DENSITY; SPIRAL GALAXIES; 3-DIMENSIONAL DISTRIBUTION; ROTATION CURVES; KINEMATICS; SUN; STARS; EQUATIONS; STABILITY; VELOCITY AB A closed system of velocity moment equations describing the three-dimensional kinematics of a cool galactic disk is developed. Truncation of the infinite hierarchy of moment equations is achieved by demanding that the kurtoses or dimensionless fourth moments of the distribution function match those of the Schwarzschild distribution function to only one higher order in a small expansion parameter (or ratio of dispersion speed to rotation speed) than is forced mathematically. It is shown that unique solutions for the velocity ellipsoid are obtainable everywhere once a potential of any kind is chosen. An essentially model-free analytic expression for the tilting of the velocity ellipsoid at points just above the plane is presented, which is in excellent agreement with all known constraints. A further analytic result is an expression for the nonisothermality of a disk population close to the plane of symmetry, which is also in detailed agreement with observations. In particular, it is shown that for all reasonable potentials the vertical velocity dispersion has a minimum on the plane. More generally, a simple expression is obtained which illustrates the close relationship between the nonisothermality and the tilting of the velocity ellipsoid, and it is also shown that the extended fluid model satisfies exactly the requirements of a diagonal velocity ellipsoid with respect to cylindrical coordinates when the potential is separable in those coordinates. Also provided is an analytical confirmation of the suggestion of van der Kruit that the answer to the long-standing question of isothermal versus exponential galactic disks is a solution intermediate between these two cases. The closed system of equations should prove useful in understanding the behavior of the velocity ellipsoid off the plane of the Milky Way, which in turn is of vital importance in determining such fundamental quantities as the column density and the amount and distribution of dark matter in the solar neighborhood. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. OSSERV ASTRON TRIESTE,I-34131 TRIESTE,ITALY. RP AMENDT, P (reprint author), SCUOLA INT SUPER STUDI AVANZATI,STRADA COSTIERA 11,I-34014 TRIESTE,ITALY. NR 90 TC 31 Z9 32 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 1991 VL 368 IS 1 BP 79 EP 104 DI 10.1086/169672 PN 1 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EU508 UT WOS:A1991EU50800008 ER PT J AU LASSILA, KE SUKHATME, UP AF LASSILA, KE SUKHATME, UP TI ANALOG OF THE EMC EFFECT IN NEUTRINO-NUCLEUS INTERACTIONS SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article AB We have recently demonstrated that the main features of the EMC effect at all x follow straightforwardly if multiquark clusters exist in nuclei with physically reasonably probabilities. Here, we examine neutrino and antineutrino reactions as possible ways to explore multiquark clusters and other sources of the EMC effect. We find that the neutrino and antineutrino probes are able to emphasize different momentum fraction regions and allow discriminating experiments to be done. RP LASSILA, KE (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 9128, SINGAPORE SN 0217-751X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD FEB 10 PY 1991 VL 6 IS 4 BP 613 EP 623 DI 10.1142/S0217751X91000368 PG 11 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA ET593 UT WOS:A1991ET59300005 ER PT J AU DEPAOLO, DJ LINN, AM SCHUBERT, G AF DEPAOLO, DJ LINN, AM SCHUBERT, G TI THE CONTINENTAL CRUSTAL AGE DISTRIBUTION - METHODS OF DETERMINING MANTLE SEPARATION AGES FROM SM-ND ISOTOPIC DATA AND APPLICATION TO THE SOUTHWESTERN UNITED-STATES SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS LA English DT Article ID TRACE-ELEMENT CONSTRAINTS; NORTHERN GREAT-BASIN; 1.9-1.7 GA AGE; ISLAND-ARC; PENINSULAR RANGES; THERMAL EVOLUTION; TERTIARY GRANITE; VOLCANIC-ROCKS; SIERRA-NEVADA; EARTHS CRUST AB Samarium-neodymium isotope systematics provide a means of determining the age of the continental crust, where "age" refers to the amount of time the crustal rock material has been isolated from the convecting mantle. This age is referred to as the Sm-Nd model age or the mantle separation age. Systematic analysis of rocks from the continents can be used to determine the age distribution by mass in the continents; this is a unique record of the thermal and chemical evolution of Earth over almost 4 b.y. The establishment of mantle separation ages for crustal rock reservoirs requires precise geochronological information typically provided by U-Pb isotopic measurements of zircon, plus models for (1) Nd isotopic evolution in the mantle source of continental crust, (2) Nd isotopic evolution of crustal reservoirs subsequent to formation, (3) petrogenesis of certain types of granitic rocks in the crust, (4) the mechanisms of formation of hybrid crust (mixtures of material newly differentiated from the mantle with material derived from older crust), and (5) the evolution of the lower parts of the continental crust during continental margin magmatism and intracontinental extension. Methods are presented for treating isotopic data on continental rock materials to obtain meaningful mantle separation ages. The greatest uncertainties come from a lack of adequate information on lower crustal processes and composition. The methods are applied to the Precambrian and Mesozoic rocks of the southwestern United States to produce a mass-age distribution for the region, which represents 1% of the global continental mass. The results suggest episodic crustal growth, with short growth periods at circa 2.8, 1.8, and 0.1 Ga. About 90% of the crust was formed by 1.8 Ga, the remaining 10% was added in the Phanerozoic. The mean age of this section of continent is determined to be 1.84 Ga. Almost all of the Phanerozoic addition occur in areas where there was no preexisting continental basement; Mesozoic magmatic additions account for only about 2% of the crustal mass in the area undertain by Precambrian basement. In the region of post-Precambrian continental growth, the regions farthest from the Precambrian continental edge are composed of mostly (> 85%) of material newly differentiated from the mantle. Adjacent to the Precambrian continental edge the new crust is typically composed about 50% of material newly differentiated from the mantle and 50% of old crustal material. There is no correlation between crustal thickness and the crust formation age in the area studied; the age-area and age-mass curves are nearly identical. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720. UNIV CALIF LOS ANGELES,DEPT EARTH & SPACE SCI,LOS ANGELES,CA 90024. RP DEPAOLO, DJ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY CTR ISOTOPE GEOCHEM,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720, USA. NR 64 TC 293 Z9 318 U1 5 U2 23 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOLID PD FEB 10 PY 1991 VL 96 IS B2 BP 2071 EP 2088 DI 10.1029/90JB02219 PG 18 WC Geosciences, Multidisciplinary SC Geology GA EX668 UT WOS:A1991EX66800012 ER PT J AU BECK, SL CHRISTENSEN, DH AF BECK, SL CHRISTENSEN, DH TI RUPTURE PROCESS OF THE FEBRUARY 4, 1965, RAT ISLANDS EARTHQUAKE SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH AND PLANETS LA English DT Article ID SUBDUCTION ZONE EARTHQUAKES; LARGE SHALLOW EARTHQUAKES; COMPLEX BODY WAVES; GREAT EARTHQUAKES; P-WAVES; ASPERITY DISTRIBUTION; SPATIAL-DISTRIBUTION; ALEUTIAN ARC; INVERSION; SEISMICITY AB The great Rat Islands underthrusting earthquake (M(w) = 8.7), of February 4, 1965, represents subduction of the Pacific plate beneath the North American plate along a 600-km segment of the western end of the Aleutian Islands. Body wave inversion technique are used to determine the spatial and temporal heterogeneities associated with the Rat Island earthquake. We have deconvolved World-Wide Standard Seismograph Network long-period toleseismic P wave seismograms to obtain source time functions. Directivity associated with the three major pulses of moment release in the source time functions indicates a total source duration of 160 s, unilateral rupture in the direction 300-degrees, fault length of 420 km, and average rupture velocity of 2.5 km/s. The three pulses of moment release are located along the fault, and these regions of high moment release are interpreted as asperities. The first asperity extends from the epicenter to 100 km to the WNW. This is the largest asperity and corresponds to a smooth pulse of moment release in the source time function with a duration of 50 s. The second pulse of moment release is very jagged, is less coherent between stations, and is centered approximately 200 km WNW of the epicenter. The third pulse of moment release extends from 360 to 420 km WNW of the epicenter. Although the aftershock area is approximately 600 km in length, we can not resolve any moment release from the P waves beyond approximately 420 km WNW of the epicenter. The Rat Islands event was closely followed by a large tensional outer-rise event on March 30, 1965, (M(s) = 7.5), which is located oceanward of the largest moment release associated with the Rat Islands mainshock rupture. Detailed analysis of the P waves for this large outer-rise event confine the depth extent to the upper 30-35 km of the curst. The spatial and temporal association between the February 4 mainshock and the March 30 tensional outer-rise event suggests the tensional event may have been triggered by the large displacement near the mainshock epicenter. The overriding plate along the western Aleutian subduction zone is laterally segmented into a series of rigid tectonic blocks separated by fault controlled canyons and extensional basins (Geist et al., 1988). We suggest that the central undeformed parts of the blocks have the strongest coupling with the down-going plate and hence are the sites of the largest moment release during an underthrusting earthquake. The three asperities determined from the P waves correspond to the Rat, Buldir, and Near tectonic blocks respectively. Hence the P wave seismic moment release of the Rat Islands earthquake is controlled by the lateral segmentation of the overriding plate. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT EARTH SCI,LIVERMORE,CA 94550. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. UNIV ALASKA,INST GEOPHYS,FAIRBANKS,AK 99701. RP BECK, SL (reprint author), UNIV ARIZONA,DEPT GEOPHYS,TUCSON,AZ 85721, USA. NR 55 TC 43 Z9 44 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES-SOLID PD FEB 10 PY 1991 VL 96 IS B2 BP 2205 EP 2221 DI 10.1029/90JB02092 PG 17 WC Geosciences, Multidisciplinary SC Geology GA EX668 UT WOS:A1991EX66800020 ER PT J AU THOMLINSON, W GMUR, N CHAPMAN, D GARRETT, R LAZARZ, N MORRISON, J REISER, P PADMANABHAN, V ONG, L GREEN, S THOMPSON, A ZEMAN, H HOFSTADTER, R BROWN, G GIACOMINI, J GORDON, H RUBENSTEIN, E AF THOMLINSON, W GMUR, N CHAPMAN, D GARRETT, R LAZARZ, N MORRISON, J REISER, P PADMANABHAN, V ONG, L GREEN, S THOMPSON, A ZEMAN, H HOFSTADTER, R BROWN, G GIACOMINI, J GORDON, H RUBENSTEIN, E TI VENOUS SYNCHROTRON CORONARY ANGIOGRAPHY SO LANCET LA English DT Letter C1 CORNELL UNIV,N SHORE UNIV HOSP,COLL MED,DEPT MED,MANHASSET,NY 11030. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV TENNESSEE,CTR HLTH SCI,MEMPHIS,TN 38163. STANFORD UNIV,DEPT PHYS,STANFORD,CA 94305. STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA. STANFORD UNIV,MED CTR,SCH MED,DEPT MED,STANFORD,CA 94305. RP THOMLINSON, W (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 3 TC 19 Z9 19 U1 0 U2 0 PU LANCET LTD PI LONDON PA 42 BEDFORD SQUARE, LONDON, ENGLAND WC1B 3SL SN 0140-6736 J9 LANCET JI Lancet PD FEB 9 PY 1991 VL 337 IS 8737 BP 360 EP 360 DI 10.1016/0140-6736(91)90986-Y PG 1 WC Medicine, General & Internal SC General & Internal Medicine GA EX362 UT WOS:A1991EX36200034 PM 1671250 ER PT J AU AMES, BN GOLD, LS AF AMES, BN GOLD, LS TI CARCINOGENS AND HUMAN HEALTH .3. REPLY SO SCIENCE LA English DT Letter ID CHEMICALS; POTENCY; ANIMALS; RANKING; HAZARDS C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CARCINOGENESIS POTENCY DATABASE,BERKELEY,CA 94720. RP AMES, BN (reprint author), UNIV CALIF BERKELEY,DEPT MOLEC & CELL BIOL,BERKELEY,CA 94720, USA. NR 17 TC 10 Z9 10 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 8 PY 1991 VL 251 IS 4994 BP 607 EP 608 DI 10.1126/science.251.4994.607 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EW399 UT WOS:A1991EW39900005 PM 17741357 ER PT J AU KOURES, AG HARDING, LB AF KOURES, AG HARDING, LB TI ABINITIO EXAMINATION OF THE ELECTRONIC EXCITATION SPECTRUM OF CCH SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID COLOR CENTER LASER; SUBMILLIMETER-WAVE SPECTRA; BOND-DISSOCIATION ENERGY; RADICAL V3 BAND; KINETIC SPECTROSCOPY; MOLECULAR CALCULATIONS; POTENTIAL SURFACES; INFRARED-EMISSION; MILLIMETER-WAVE; EXCITED C2H AB Large-scale MCSCF/MRSDCI calculations have been performed to examine the vertical electronic excitation spectrum of the ethynyl radical. Valence, Rydberg, and cationic states are calculated and discussed. The two observed UV transitions are discussed, and an assignment to the 8.9-eV transition observed by T. A. Cool is made. A value for the adiabatic ionization potential which is believed to be within +/- 0.1 eV of the true value is given, and its implication on the recent acetylene bond dissociation energy controversy is discussed. Comparison is made to an older study by Shih et al. and generally shows reasonable agreement with a few significant differences which are discussed. C1 ARGONNE NATL LAB, DIV CHEM, THEORET CHEM GRP, ARGONNE, IL 60439 USA. NR 61 TC 26 Z9 26 U1 1 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 7 PY 1991 VL 95 IS 3 BP 1035 EP 1040 DI 10.1021/j100156a004 PG 6 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800004 ER PT J AU HUNT, RD ANDREWS, L MACTOTH, L AF HUNT, RD ANDREWS, L MACTOTH, L TI INFRARED-SPECTRA OF UF6, WF6, MOF6, AND SF6 COMPLEXES WITH HYDROGEN-FLUORIDE IN SOLID ARGON SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ION-CYCLOTRON RESONANCE; BONDED COMPLEXES; CHEMICAL-LASER; FTIR SPECTRA; HF; ELECTRON; 12-K; SPECTROSCOPY; PHOTOLYSIS; CONSTANTS AB UF6, WF6, MoF6, and SF6 have been codeposited with hydrogen fluoride in excess argon at 12 K. The FTIR spectra of UF6, and HF revealed a strong UF6-HF complex absorption at 3848 cm-1 along with a weak, broad band at 3903 cm-1 due to the UF6-FH complex. Only one 1:2 complex with a UF6-H(a)F-H(b)F arrangement was detected at higher HF concentrations and sample annealings. Similarly, the HF interaction with tungsten hexafluoride formed two 1:1 complexes. However, the 3884-cm-1 band due to the anti-hydrogen-bonded complex WF6-FH was considerably stronger than the WF6-Hf absorption at 3911 cm-1. Increasing the HF concentration produced a single 1:2 complex with a WF6-FH(b)-FH(a) structure. The band positions and relative intensities for the MoF6 complexes with HF and DF were very comparable to their WF6 counterparts. This change in the dominant binding interaction for these HF-metal hexafluoride complexes was anticipated due to the significant difference in the fluoride affinities of UF6 and WF6 (46 and 69 kcal/mol, respectively). In sharp contrast to the metal hexafluorides, SF6 and HF produced a weak triplet at 3905, 3903, and 3901 cm-1 and a strong doublet at 3819 and 3818 cm-1, which are tentatively assigned to the SF6-HF and SF6-H(a)F-H(b)F structures, respectively. Finally, 1:3 and 1:4 complexes were observed with each hexafluoride, and the structures of these HF complexes are determined by the cyclic nature of the HF polymers. C1 UNIV VIRGINIA,DEPT CHEM,CHARLOTTESVILLE,VA 22901. RP HUNT, RD (reprint author), OAK RIDGE NATL LAB,DIV CHEM TECHNOL,OAK RIDGE,TN 37831, USA. NR 30 TC 6 Z9 6 U1 2 U2 6 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 7 PY 1991 VL 95 IS 3 BP 1183 EP 1188 DI 10.1021/j100156a028 PG 6 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800028 ER PT J AU WERST, DW TRIFUNAC, AD AF WERST, DW TRIFUNAC, AD TI TRANSIENT ALKYLAMINIUM RADICALS IN NORMAL-HEXANE - CONDENSED-PHASE ION MOLECULE REACTIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRON-SPIN-RESONANCE; DETECTED MAGNETIC-RESONANCE; STILBENE-AMINE EXCIPLEXES; PULSE-RADIOLYSIS; CATION RADICALS; PARAMAGNETIC RESONANCE; PHOTOCHEMICAL ADDITION; ALIPHATIC-AMINES; PROTON-TRANSFER; FREON MATRICES AB Time-resolved fluorescence detected magnetic resonance (FDMR) is used to observe alkylaminium radicals formed in n-hexane solutions by electron pulse radiolysis. The ease of observation of aminium radical FDMR signals increases with increasing alkyl substitution of the amine solutes. The results are discussed in terms of the ion-molecule reactions, such as proton transfer, which compete with the electron-transfer processes, i.e., the electron transfer from solute molecules to n-hexane radical cations and geminate recombination. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 71 TC 14 Z9 14 U1 1 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 7 PY 1991 VL 95 IS 3 BP 1268 EP 1274 DI 10.1021/j100156a043 PG 7 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800043 ER PT J AU ANNEN, MJ YOUNG, D DAVIS, ME CAVIN, OB HUBBARD, CR AF ANNEN, MJ YOUNG, D DAVIS, ME CAVIN, OB HUBBARD, CR TI THERMAL AND HYDROTHERMAL STABILITY OF MOLECULAR-SIEVE VPI-5 BY INSITU X-RAY-POWDER DIFFRACTION SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID NEUTRON AB The framework stability of the molecular sieve VPI-5 is studied at various conditions of temperature, pressure, and humidity. Dehydration of VPI-5, by either rapid heating or pressure reduction, leads to a contraction in "a" and an expansion in "c" (hexagonal cell). These changes are reversible upon rehydration. The transformation of VPI-5 into AlPO4-8 depends on the rate at which water is removed from the pores. Slow heating results in the irreversible formation of AlPO4-8 from VPI-5 at about 100-degrees-C. However, VPI-5 rapidly heated to at least 550-degrees-C can withstand exposure to steam at these elevated temperatures with little loss of structural integrity. C1 VIRGINIA POLYTECH INST & STATE UNIV,DEPT CHEM ENGN,BLACKSBURG,VA 24061. OAK RIDGE NATL LAB,HIGH TEMP MAT LAB,OAK RIDGE,TN 37831. NR 18 TC 52 Z9 52 U1 0 U2 0 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 7 PY 1991 VL 95 IS 3 BP 1380 EP 1383 DI 10.1021/j100156a064 PG 4 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800064 ER PT J AU YEE, GG FULTON, JL BLITZ, JP SMITH, RD AF YEE, GG FULTON, JL BLITZ, JP SMITH, RD TI FT-IR INVESTIGATION OF THE PARTITIONING OF SODIUM BIS(2-ETHYLHEXYL) SULFOSUCCINATE BETWEEN AN AQUEOUS AND A PROPANE PHASE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ANGLE NEUTRON-SCATTERING; IN-OIL MICROEMULSIONS; REVERSE MICELLES; 3-COMPONENT MICROEMULSIONS; SELECTIVE SOLUBILIZATION; NONPOLAR-SOLVENTS; GENERAL PATTERNS; WATER; BEHAVIOR; PROTEINS AB The partitioning of the surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) from a buffered aqueous phase into a near-critical propane phase was investigated by using Fourier transform infrared spectroscopy. The partitioning of AOT is shown to be dependent upon the fluid pressure as well as upon the molar water-to-surfactant ratio, W. The uptake of water into the propane microemulsion phase coincides with the partitioning of AOT. The phase behavior of this system appears to be controlled by the attractive interactions between droplets in the microemulsion phase, as well as from limitations upon the curvature of the interfacial surfactant layer. Potential applications of these systems for separations are discussed. C1 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 NR 34 TC 13 Z9 13 U1 0 U2 6 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 7 PY 1991 VL 95 IS 3 BP 1403 EP 1409 DI 10.1021/j100156a069 PG 7 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800069 ER PT J AU MELIUS, CF HO, P AF MELIUS, CF HO, P TI THEORETICAL-STUDY OF THE THERMOCHEMISTRY OF MOLECULES IN THE SI-N-H-F SYSTEM SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID CHEMICAL VAPOR-DEPOSITION; ELECTRON CORRELATION-ENERGY; PLESSET PERTURBATION-THEORY; SILICON-NITRIDE; GAS-PHASE; MODEL; CHEMISTRY; KINETICS; HEATS; SILYL AB A self-consistent set of heats of formation for over 30 molecules in the Si-N-F system is obtained from a combination of ab initio electronic structure calculations and empirical corrections. The molecules studied include the H(n)SiNH(m) and F(n)SiNH(m) species, some of the H(n)Si(NH2)m, F(n)Si(NH2)m, and H(n)N(SiH3)m(SiF3)l species, and several transition states for the decomposition of silylamine. C1 SANDIA NATL LABS, DIV 1126, ALBUQUERQUE, NM 87185 USA. RP MELIUS, CF (reprint author), SANDIA NATL LABS, COMBUST RES FACIL, LIVERMORE, CA 94551 USA. NR 52 TC 63 Z9 64 U1 0 U2 4 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 7 PY 1991 VL 95 IS 3 BP 1410 EP 1419 DI 10.1021/j100156a070 PG 10 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800070 ER PT J AU TINGEY, JM FULTON, JL MATSON, DW SMITH, RD AF TINGEY, JM FULTON, JL MATSON, DW SMITH, RD TI MICELLAR AND BICONTINUOUS MICROEMULSIONS FORMED IN BOTH NEAR-CRITICAL AND SUPERCRITICAL PROPANE WITH DIDODECYLDIMETHYLAMMONIUM BROMIDE AND WATER SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID IONIC MICROEMULSIONS; INTERFACIAL-TENSION; REVERSE MICELLE; PHASE; SURFACTANTS; BEHAVIOR; FLUIDS AB Bicontinuous microemulsions readily form in liquid propane at 25-degrees-C and pressures from 10 to 500 bar with the addition of the surfactant didodecyldimethylammonium bromide (DDAB) and water. The phase behavior of this system is much like that of the normal liquid alkanes, C6-C-10, but with unusual and dramatic effects due to pressure. When the pressure of the solution is increased from 80 to 400 bar with the addition of pure propane, the conductivity is observed to decrease by 3 orders of magnitude. In accord with existing structural models for conventional liquid microemulsion systems, these changes in the conductivity are ascribed to changes in the interface region as the propane solvent penetrates and solvates the hydrocarbon tails of the surfactant. The corresponding supercritical propane system studied at 100-degrees-C is best explained as a micellar microemulsion with an oil-continuous phase in which the structure is also affected by the amount of water or the pressure of the system. C1 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 NR 15 TC 25 Z9 25 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 7 PY 1991 VL 95 IS 3 BP 1445 EP 1448 DI 10.1021/j100156a075 PG 4 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800075 ER PT J AU SMITH, DH COVATCH, GC LIM, KH AF SMITH, DH COVATCH, GC LIM, KH TI TEMPERATURE-DEPENDENCE OF EMULSION MORPHOLOGIES AND THE DISPERSION MORPHOLOGY DIAGRAM SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID WATER I-C9H19C6H4(OC2H4)9.2OH; CRITICAL-POINTS; SYSTEMS AB The recently constructed "dispersion morphology diagram" predicts that for amphiphile/oil/water systems there exists a range of concentrations within which only OL/AQ ("oil-in-water") emulsions form and another range of concentrations for which the emulsion morphology is always AQ/OL ("water-in-oil"), regardless of whether the temperature is below the lower critical end-point temperature, above the upper critical end point, or between these two temperatures. These predictions contradict the PIT (phase inversion temperature) idea, that below the PIT amphiphile/oil/water systems form only "oil-in-water" emulsions and above the PIT they form only "water-in-oil" emulsions. By using electrical conductivity measurements to determine the emulsion morphologies at different temperatures for systems for constant composition, we show for the system studied that the previous predictions of the dispersion morphology diagram are correct. C1 UNIV OKLAHOMA,INST APPL SURFACTANT RES,NORMAN,OK 73019. UNIV OKLAHOMA,DEPT CHEM ENGN,NORMAN,OK 73019. RP SMITH, DH (reprint author), US DOE,MORGANTOWN ENERGY TECHNOL CTR,MORGANTOWN,WV 26507, USA. NR 18 TC 20 Z9 20 U1 1 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 7 PY 1991 VL 95 IS 3 BP 1463 EP 1466 DI 10.1021/j100156a079 PG 4 WC Chemistry, Physical SC Chemistry GA EW478 UT WOS:A1991EW47800079 ER PT J AU HAYTER, JB AF HAYTER, JB TI DETERMINATION OF STRUCTURES IN FERROFLUIDS BY SMALL-ANGLE NEUTRON-SCATTERING SO JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS LA English DT Article ID COLLOIDAL MAGNETIC PARTICLES; MEAN SPHERICAL MODEL; DIPOLAR FLUIDS; X-RAY; MIXTURES; CRYSTALS AB Stable colloidal dispersions of magnetic particles, or ferrofluids, form a technologically important class of magnetic fluids with novel structural features at the microscopic level. Small-angle neutron scattering (SANS) has proved to be ideally suited to the study of such structures. In addition to the techniques of neutron refractive index variation which have made SANS a tool of choice for studying colloids in general, the uniquely powerful methods of neutron polarisation analysis may be applied to ferrofluids, providing a selection rule for studying non-magnetic and magnetic structural features separately. This article considers the application of SANS to studies of dilute ferrofluids, after which extension of the techniques to concentrated (interacting) dispersions will be addressed. Advances in understanding binary colloidal mixtures in which at least one component is magnetic will then be considered. Finally, the use of ferrodispersion to generate ordered colloidal structures in ferrofluids will be discussed. RP HAYTER, JB (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,POB 2008,OAK RIDGE,TN 37831, USA. NR 56 TC 12 Z9 12 U1 0 U2 2 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0956-5000 J9 J CHEM SOC FARADAY T JI J. Chem. Soc.-Faraday Trans. PD FEB 7 PY 1991 VL 87 IS 3 BP 403 EP 410 DI 10.1039/ft9918700403 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY240 UT WOS:A1991EY24000006 ER PT J AU BAKTASH, C GARCIABERMUDEZ, G SARANTITES, DG NAZAREWICZ, W ABENANTE, V BEENE, JR GRIFFIN, HC HALBERT, ML HENSLEY, DC JOHNSON, NR LEE, IY MCGOWAN, FK RILEY, MA STRACENER, DW SEMKOW, TM VIRTANEN, A AF BAKTASH, C GARCIABERMUDEZ, G SARANTITES, DG NAZAREWICZ, W ABENANTE, V BEENE, JR GRIFFIN, HC HALBERT, ML HENSLEY, DC JOHNSON, NR LEE, IY MCGOWAN, FK RILEY, MA STRACENER, DW SEMKOW, TM VIRTANEN, A TI SHAPE COEXISTENCE AND DISAPPEARANCE OF PAIRING CORRELATIONS IN SR-82 SO PHYSICS LETTERS B LA English DT Article ID HIGH-SPIN; BAND CROSSINGS; IN-BEAM; ROTATION; BEHAVIOR; NUCLEI; KR-76 AB Extensive high-spin band structures in Sr-82 have been established using proton-gamma-gamma coincidence techniques. On the basis of the Woods-Saxon cranking calculations with pairing, four of these bands are interpreted to have prolate, oblate, or triaxial shapes. Pairing correlations are predicted to be very weak at high spins in this nucleus, and calculations with no static pairing successfully reproduce the experimentally observed crossing frequencies and alignments despite the fact that none of the bands displays a rigid-rotor behavior. It is concluded that observation of rigid-rotor behavior is neither necessary nor sufficient for the disappearance of static pairing in nuclei. C1 JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. UNIV LIVERPOOL,OLIVER LODGE LAB,LIVERPOOL L69 3BZ,ENGLAND. WASHINGTON UNIV,DEPT CHEM,ST LOUIS,MO 63130. UNIV MICHIGAN,DEPT CHEM,ANN ARBOR,MI 48109. COMIS NACL ENERGIA ATOM,RA-1429 BUENOS AIRES,ARGENTINA. RP BAKTASH, C (reprint author), OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37830, USA. OI Virtanen, Ari/0000-0002-6591-6787 NR 26 TC 28 Z9 28 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 7 PY 1991 VL 255 IS 2 BP 174 EP 179 DI 10.1016/0370-2693(91)90232-F PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ329 UT WOS:A1991EZ32900004 ER PT J AU GINSPARG, P ZINNJUSTIN, J AF GINSPARG, P ZINNJUSTIN, J TI LARGE ORDER BEHAVIOR OF NONPERTURBATIVE GRAVITY SO PHYSICS LETTERS B LA English DT Article AB We study the large order behavior and Borel summability of the topological expansion of models of 2D gravity coupled to matter. We treat in particular the cases of pure gravity, and gravity coupled to Yang-Lee, Ising, and tricritical Ising matter. We then discuss arbitrary one-matrix models and gravity coupled to general (p, q) conformal matter, in particular showing that the genus-k contribution to their partition functions goes asymptotically for large k as GAMMA(2k-1/2). Finally, we show that the large order behavior analysis for the one-matrix models coincides with an instanton calculation of barrier penetration effects. C1 SERV PHYS THEOR SACLAY,F-91191 GIF SUR YVETTE,FRANCE. RP GINSPARG, P (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MS-B285,LOS ALAMOS,NM 87545, USA. NR 25 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 7 PY 1991 VL 255 IS 2 BP 189 EP 196 DI 10.1016/0370-2693(91)90234-H PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EZ329 UT WOS:A1991EZ32900006 ER PT J AU MIEDANER, A HALTIWANGER, RC DUBOIS, DL AF MIEDANER, A HALTIWANGER, RC DUBOIS, DL TI RELATIONSHIP BETWEEN THE BITE SIZE OF DIPHOSPHINE LIGANDS AND TETRAHEDRAL DISTORTIONS OF SQUARE-PLANAR NICKEL(II) COMPLEXES - STABILIZATION OF NICKEL(I) AND PALLADIUM(I) COMPLEXES USING DIPHOSPHINE LIGANDS WITH LARGE BITES SO INORGANIC CHEMISTRY LA English DT Article ID ELECTRON-SPIN-RESONANCE; STRUCTURAL CHARACTERIZATION; COORDINATION-COMPOUNDS; ELECTROANALYTICAL APPROACH; ELECTROCHEMICAL REDUCTION; PHOSPHINE COMPLEXES; OXIDATIVE ADDITION; PHOSPHORUS LIGANDS; ZEROVALENT NICKEL; ORGANIC HALIDES AB Nickel and palladium complexes of the type [M(L2)2](BF4)2 and [M(L2)(L2')](BF4)2 (where L2 and L2' are diphosphine ligands) have been synthesized. The lowest energy electronic absorption band for the nickel complexes decreases in energy as the bite size of the diphosphine ligand increases. Similarly, the half-wave potentials for the Ni(II/I) and Pd(II/0) couples become more positive as the bite size increases. Structural studies of [Ni(dppm)2](BF4)2 (where dppm is bis(diphenylphosphino)methane) and [Ni(dppb)2](PF6)2 (where dppb is 1,2-bis(diphenylphosphino)benzene) show that increasing the bite size of the diphosphine ligands results in larger tetrahedral distortions. [Ni(dppm)2](BF4)2 (C50H44B2F8NiP4) crystallizes in the monoclinic space group P2(1/n) with a = 11.158 (10) angstrom, b = 17.43 (2) angstrom, c = 12.849 (11) angstrom, beta = 111.38 (7)-degrees, V = 3228 angstrom3, and Z = 2. The structure was refined to R = 0.155 and R(W) = 0.201 for 1005 independent reflections with F(o) > 6-sigma-(F(o)). [Ni(dppb)2](PF6)2 (C74H64F12NiP6) crystallizes in space group P1BAR with a = 11.359 (6) angstrom, b = 13.960 (5) angstrom, c = 21.297 (7) angstrom, alpha = 84.69 (3)-degrees, beta = 84.79 (4)-degrees, gamma = 78.96 (3)-degrees, V = 3298 (2) angstrom3, and Z = 2. The structure was refined to R = 0.072 and R(W) = 0.085 for 2333 independent reflections with F(o) > 6-sigma-(F(o)). The tetrahedral distortion observed for [Ni(dppb)2](PF6)2 was modeled by using extended Huckel calculations. These calculations indicate that the observed distortion may have an electronic as well as a steric component. The calculations also allow rationalization of the electronic absorption spectra, electrochemical data, and the stability of the Ni(I) and Pd(I) complexes [Ni(dppp)2](BF4) (where dppp is 1,3-bis(diphenylphosphino)propane) and [Pd(dppx)2](BF4) (where dppx is alpha,alpha'-bis(diphenyl-phosphino)-o-xylene). Complexes containing the ligand dppm have a marked tendency to become five-coordinate, as indicated by the structural determination of [Ni(dppm)2(CH3CN)](PF6)2. The latter complex (C59H55F12NNiP6) crystallizes in space group P4/m with a = 19.363 (4) angstrom, c = 15.526 (4) angstrom, V = 5822 (2) angstrom3, and Z = 4. The structure was refined to R = 0.048 and R(W) = 0.062 for 3470 independent reflections with F(o) > 6-sigma-(F(o)). C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. UNIV COLORADO,DEPT CHEM & BIOCHEM,BOULDER,CO 80309. NR 77 TC 93 Z9 93 U1 1 U2 8 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 6 PY 1991 VL 30 IS 3 BP 417 EP 427 DI 10.1021/ic00003a012 PG 11 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EW602 UT WOS:A1991EW60200012 ER PT J AU BAKAC, A BUTKOVIC, V ESPENSON, JH MARCEC, R ORHANOVIC, M AF BAKAC, A BUTKOVIC, V ESPENSON, JH MARCEC, R ORHANOVIC, M TI PREPARATION OF A SERIES OF (IMIDAZOLE)PENTAAQUACHROMIUM(III) COMPLEXES AND KINETICS OF THEIR REDUCTION BY 1-HYDROXY-1-METHYLETHYL RADICALS SO INORGANIC CHEMISTRY LA English DT Article ID 2-HYDROXY-2-PROPYL RADICALS; ALIPHATIC RADICALS; ELECTRON-TRANSFER; IONS; MECHANISM; OXIDATION; AQUATION AB A series of (imidazole) pentaaquachromium(III) complexes, (H2O)5Cr(Im-X,Y)3+ were prepared and characterized in acidic aqueous solution. These complexes are reduced by .C(CH3)2OH radicals with rate constants that vary with substituents on the imidazole ring. At 25-degrees-C the values of the rate constants, k/10(5) L mol-1 s-1 (X, Y), are 1.1 (1-CH3, H), 2.1 (2-CH3, H), 3.8 (4-CH3, H), 6.6 (H, H), 7.2 (4-CH3, 5-CONH2), and 16 (4-Cl, 5-Cl). A mechanism is proposed whereby the initial electron transfer takes place at coordinated imidazole, followed by a rapid intramolecular electron transfer to yield Cr(H2O)6(2+) and X,Y-ImH+. C1 RUDJER BOSKOVIC INST, YU-41000 ZAGREB, YUGOSLAVIA. IOWA STATE UNIV SCI & TECHNOL, DEPT CHEM, AMES, IA 50011 USA. RP BAKAC, A (reprint author), IOWA STATE UNIV SCI & TECHNOL, AMES LAB, AMES, IA 50011 USA. NR 22 TC 4 Z9 4 U1 0 U2 0 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 6 PY 1991 VL 30 IS 3 BP 481 EP 483 DI 10.1021/ic00003a024 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EW602 UT WOS:A1991EW60200024 ER PT J AU SZALDA, DJ SCHWARZ, CL CREUTZ, C AF SZALDA, DJ SCHWARZ, CL CREUTZ, C TI SYNTHESIS AND STRUCTURE OF TRANS-SEC,RAC-[COL(CH3)(H2O)](CF3SO3)2 - L = 5,7,7,12,14,14-HEXAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECA-4,11-DIENE - STERIC SELECTIVITY IN ALKYL RADICAL METAL RADICAL REACTIONS SO INORGANIC CHEMISTRY LA English DT Note ID COBALT(II) COMPLEXES; LOW-SPIN; CRYSTAL; MACROCYCLE; BINDING; LIGANDS; SYSTEM; BONDS; CO2 C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. NR 21 TC 11 Z9 11 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 6 PY 1991 VL 30 IS 3 BP 586 EP 588 DI 10.1021/ic00003a051 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EW602 UT WOS:A1991EW60200051 ER PT J AU THOR, A BENZ, C MOORE, D GOLDMAN, E EDGERTON, S LANDRY, J SCHWARTZ, L MAYALL, B HICKEY, E WEBER, LA AF THOR, A BENZ, C MOORE, D GOLDMAN, E EDGERTON, S LANDRY, J SCHWARTZ, L MAYALL, B HICKEY, E WEBER, LA TI STRESS RESPONSE PROTEIN (SRP-27) DETERMINATION IN PRIMARY HUMAN BREAST CARCINOMAS - CLINICAL, HISTOLOGIC, AND PROGNOSTIC CORRELATIONS SO JOURNAL OF THE NATIONAL CANCER INSTITUTE LA English DT Article ID HEAT-SHOCK PROTEIN; REGULATED 24K PROTEIN; PROGESTERONE RECEPTORS; GENE-TRANSCRIPTION; MOLECULAR-WEIGHT; PS2 GENE; EXPRESSION; CELLS; ESTROGEN; CANCER AB Expression of an estrogen-regulated protein known as the 27000-d heat-shock or stress-response protein (srp-27) was evaluated in human breast carcinomas and established breast cancer cell lines. Results obtained by Northern and Western blot analyses and immunohistochemical methods were concordant. Immunohistochemical assessment of srp-27 expression in 300 breast carcinomas (with median patient follow-up of 8 years) was performed. Twenty-six percent of lymph node-negative and 45% of lymph node-positive tumors were overexpressors. Univariate analysis demonstrated significant correlations between srp-27 overexpression and estrogen receptor (ER) content, pS2 protein expression, nodal metastases, advanced T stage, lymphatic/vascular invasion, and a shorter disease-free survival period (but not a shorter overall survival) for the study population as a whole. Regression tree analysis showed that srp-27 expression was an independent prognostic indicator for disease-free survival only in patients with one to three positive lymph nodes. The Cox proportional hazards model confirmed the independent prognostic significance of nodal involvement, T stage, and ER content but failed to recognize srp-27 overexpression as a significant independent parameter predictive of patient outcome in the patient population as a whole. The observed associations between srp-27 overexpression and more aggressive tumors suggest a biologic role for srp-27 in human breast carcinomas. C1 MASSACHUSETTS GEN HOSP,DEPT RADIAT MED,BOSTON,MA 02114. UNIV CALIF SAN FRANCISCO,DEPT LAB MED,SAN FRANCISCO,CA 94143. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. UNIV LAVAL,CANC RES CTR,QUEBEC CITY G1K 7P4,QUEBEC,CANADA. UNIV S FLORIDA,DEPT BIOL,TAMPA,FL 33620. RP THOR, A (reprint author), MASSACHUSETTS GEN HOSP,DEPT PATHOL,FRUIT ST,BOSTON,MA 02114, USA. FU NCI NIH HHS [CA-46966, CA-44768]; NIGMS NIH HHS [GM-32381] NR 35 TC 159 Z9 160 U1 0 U2 0 PU NATL CANCER INSTITUTE PI BETHESDA PA 9030 OLD GEORGETOWN RD, BETHESDA, MD 20814 SN 0027-8874 J9 J NATL CANCER I JI J. Natl. Cancer Inst. PD FEB 6 PY 1991 VL 83 IS 3 BP 170 EP 178 DI 10.1093/jnci/83.3.170 PG 9 WC Oncology SC Oncology GA EW649 UT WOS:A1991EW64900007 PM 1988702 ER PT J AU KOSSIAKOFF, AA ULTSCH, M WHITE, S EIGENBROT, C AF KOSSIAKOFF, AA ULTSCH, M WHITE, S EIGENBROT, C TI NEUTRON STRUCTURE OF SUBTILISIN BPN' - EFFECTS OF CHEMICAL ENVIRONMENT ON HYDROGEN-BONDING GEOMETRIES AND THE PATTERN OF HYDROGEN-DEUTERIUM EXCHANGE IN SECONDARY STRUCTURE ELEMENTS SO BIOCHEMISTRY LA English DT Article ID SERINE PROTEASES; EGLIN-C; MOLECULAR-STRUCTURE; CRYSTAL-STRUCTURE; FREE-ENERGY; PROTEIN; RESOLUTION; REFINEMENT; CARLSBERG; INHIBITOR AB The neutron structure of subtilisin BPN' has been refined and analyzed at 2.0-angstrom resolution. The structure studied was a mutant variant of subtilisin, Met222 --> Gln, and was used because large, uninhibited crystals could be grown, which was not the case for the native molecule. Comparison of the structure with that of the native molecule indicated that the two structures are essentially the same. Using the capability of the neutron method to locate hydrogen and deuterium atoms, the protonation states of the six histidine residues were assigned. The active site histidine, His64, was found to be neutral at the pH of the analysis (pH 6.1). This group has an unexpectedly low pK(a) compared to assignments made by other techniques. The altered pK(a) of the group could result from electrostatic effects of other molecules in the crystal lattice. The dihedral conformations of a majority of the hydroxyl rotors were assigned. The preferred orientation was trans (180-degrees) with the other two low-energy conformers (60-degrees, 300-degrees) about equally populated. For the serines, about 21% of the hydroxyls act exclusively as H-bond acceptors and 37% as H-bond donors, and in 42% the group functions as both. The experimentally observed dihedral conformations were compared to predicted conformations based on calculated energy criteria and showed a strong correspondence. Deviation from low-energy states could usually be explained by local electrostatic effects. The hydrogen exchange pattern of subtilisin identified the beta-sheet and alpha-helix secondary structure elements to be the most resistant to exchange. Fifty-five percent of the peptide amide hydrogens were fully exchanged, 15% unexchanged, and 30% partially exchanged. The largest concentration of unexchanged sites was in the seven-stranded parallel beta-sheet, in which there were 11 fully protected groups. Little correlation was found between H-bond length and angle and a peptide group's susceptibility toward exchange. Of the five alpha-helices the most protected from exchange is the one defined by residues 224-236. The pattern of exchange identifies regions in this helix where the H-bonding regularity is disrupted. C1 UNIV CALIF SAN FRANCISCO,DEPT PHARMACEUT CHEM,SAN FRANCISCO,CA 94143. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. RP KOSSIAKOFF, AA (reprint author), GENENTECH INC,DEPT PROT ENGN,460 POINT SAN BRUNO BLVD,S SAN FRANCISCO,CA 94080, USA. FU NIGMS NIH HHS [GM33571] NR 45 TC 21 Z9 21 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 5 PY 1991 VL 30 IS 5 BP 1211 EP 1221 DI 10.1021/bi00219a008 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EW398 UT WOS:A1991EW39800008 PM 1991100 ER PT J AU DEROSE, VJ YACHANDRA, VK MCDERMOTT, AE BRITT, RD SAUER, K KLEIN, MP AF DEROSE, VJ YACHANDRA, VK MCDERMOTT, AE BRITT, RD SAUER, K KLEIN, MP TI THE STATE OF MANGANESE IN THE PHOTOSYNTHETIC APPARATUS - NITROGEN LIGATION TO MANGANESE IN THE PHOTOSYNTHETIC OXYGEN-EVOLVING COMPLEX - CONTINUOUS-WAVE AND PULSED EPR STUDIES OF PHOTOSYSTEM-II PARTICLES CONTAINING N-14 OR N-15 SO BIOCHEMISTRY LA English DT Article ID ELECTRON-SPIN-ECHO; PARAMAGNETIC-RES SIGNALS; O-2-EVOLVING COMPLEX; ENVELOPE MODULATION; WATER OXIDATION; AMMONIA BINDS; S2 STATE; RESONANCE; LIGANDS; SYSTEM AB The possibility of nitrogen ligation to the Mn in the oxygen-evolving complex from photosystem II was investigated with electron paramagnetic resonance (EPR) and electron spin echo envelope modulation (ESEEM) spectroscopies using N-14- and N-15-labeled preparations. Oxygen-evolving preparations were isolated from a thermophilic cyanobacterium, Synechococcus sp., grown on a medium containing either (NO3-)-N-15 as the sole source of nitrogen. The substructure on the "multiline" EPR signal, which arises from Mn in the S2 state of the enzyme, was measured with continous-wave EPR. No changes were detected in the substructure peak positions upon substitution of N-15 for N-14, indicating that this substructure is not due to superhyperfine coupling from nitrogen ligands. To detect potential nitrogen ligands with superhyperfine couplings of lesser magnitude than could be observed with conventional EPR methods, electron spin-echo envelope modulation experiments were also performed on the multiline EPR signal. The Fourier transform of the light-minus-dark time domain ESEEM data shows a peak at 4.8 MHz in N-14 samples which is absent upon substitution with N-15. This gives unambiguous evidence for weak hyperfine coupling of nitrogen to the Mn of the oxygen-evolving complex. Possible origins of this nitrogen interaction are discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM BIODYNAM,BERKELEY,CA 94720. NR 54 TC 94 Z9 94 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD FEB 5 PY 1991 VL 30 IS 5 BP 1335 EP 1341 DI 10.1021/bi00219a025 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EW398 UT WOS:A1991EW39800025 PM 1846751 ER PT J AU JANG, LK LOPEZ, SL EASTMAN, SL PRYFOGLE, P AF JANG, LK LOPEZ, SL EASTMAN, SL PRYFOGLE, P TI RECOVERY OF COPPER AND COBALT BY BIOPOLYMER GELS SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article ID ION AB The recovery of copper from synthetic aqueous media circulating in a loop fluidized bed reactor operated batchwise was investigated by using the following biopolymer systems: (1) a viscous solution of sodium alginate (from kelp) dispensed directly into the reactor fluid containing dissolved copper (sulfate salt) at initial concentrations of 60-200 ppm, (2) partially coagulated calcium alginate spheres for absorbing dissolved copper at initial concentrations of 10-40 ppm, and (3) a mixture of green algae Microcystis and sodium alginate dispensed directly into the reactor fluid. The recovery of copper and cobalt, a strategic metal, from cobalt ore leachate was achieved by a two-step approach: direct dispensing of sodium alginate to absorb the bulk of metals followed by the addition of partially coagulated calcium alginate spheres to "polish" the leachate. Metal binding capacity and conditional stability constant of each biopolymer system as well as the effective diffusivity of cupric ion in the matrix of biopolymer gels are reported. C1 EG&G IDAHO INC,IDAHO NATL ENGN LAB,BIOTECHNOL UNIT,IDAHO FALLS,ID 83415. RP JANG, LK (reprint author), CALIF STATE UNIV LONG BEACH,DEPT CHEM ENGN,LONG BEACH,CA 90840, USA. NR 12 TC 84 Z9 85 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD FEB 5 PY 1991 VL 37 IS 3 BP 266 EP 273 DI 10.1002/bit.260370309 PG 8 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA EU685 UT WOS:A1991EU68500008 PM 18597364 ER PT J AU ARMSTRONG, PB MANGEL, WF WALL, JS HAINFIELD, JF VANHOLDE, KE IKAI, A QUIGLEY, JP AF ARMSTRONG, PB MANGEL, WF WALL, JS HAINFIELD, JF VANHOLDE, KE IKAI, A QUIGLEY, JP TI STRUCTURE OF ALPHA-2-MACROGLOBULIN FROM THE ARTHROPOD LIMULUS-POLYPHEMUS SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID MAMMALIAN ALPHA-2-MACROGLOBULIN RECEPTOR; CRAYFISH PACIFASTACUS-LENIUSCULUS; PROTEINASE COMPLEX-FORMATION; THIOL-ESTER; ALPHA-MACROGLOBULIN; COVALENT BINDING; HALF-MOLECULES; INHIBITOR; PLASMA; HEMOLYMPH AB A structural and functional homologue of vertebrate alpha-2-macroglobulin (alpha-2M) has been identified in the hemolymph and blood cells of the arthropod Limulus polyphemus, one of the oldest living fossil invertebrates (Quigley, J.P., and Armstrong, P.B. (1985) J. Biol. Chem. 260, 12715-12719). The subunit molecular mass is 185 kDa. The native molecular mass, determined by scanning transmission electron microscopy (STEM) under conditions in which the linear relationship between the STEM large angle detector signal and specimen mass thickness allows the determination of the total macromolecular mass, was 354 +/- 35 kDa. Sedimentation equilibrium measurements gave a value of 366 kDa, independent of solute concentration. Sedimentation velocity experiments indicated a homogeneous component with a frictional ratio of 1.41. Thus, the native structure appears to be a dimer, with a somewhat extended conformation. The behavior during gel permeation chromatography was anomolous, yielding an apparent molecular mass approximately half-way between that expected for the dimeric and tetrameric configurations. Transmission electron microscopy of negatively stained preparations revealed a dimeric butterfly-like structure that collapsed following reaction with chymotrypsin. C1 UNIV CALIF DAVIS,DEPT ZOOL,CELL BIOL LAB,DAVIS,CA 95616. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. OREGON STATE UNIV,DEPT BIOCHEM & BIOPHYS,CORVALLIS,OR 97331. TOKYO INST TECHNOL,BIODYNAM LAB,YOKOHAMA,KANAGAWA 227,JAPAN. SUNY STONY BROOK,HLTH SCI CTR,DEPT PATHOL,STONY BROOK,NY 11794. RP ARMSTRONG, PB (reprint author), MARINE BIOL LAB,WOODS HOLE,MA 02543, USA. FU NCRR NIH HHS [RR 01777]; NIGMS NIH HHS [GM 35185] NR 45 TC 34 Z9 34 U1 0 U2 0 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 5 PY 1991 VL 266 IS 4 BP 2526 EP 2530 PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EV515 UT WOS:A1991EV51500078 PM 1703530 ER PT J AU LU, M GUO, Q STUDIER, FW KALLENBACH, NR AF LU, M GUO, Q STUDIER, FW KALLENBACH, NR TI RESOLUTION OF BRANCHED DNA SUBSTRATES BY T7 ENDONUCLEASE-I AND ITS INHIBITION SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID HOLLIDAY JUNCTION ANALOGS; GENETIC-RECOMBINATION; GENE-49-CONTROLLED ENDONUCLEASE; SACCHAROMYCES-CEREVISIAE; GENE-3 ENDONUCLEASE; T4-HEAD MATURATION; CRUCIFORM DNA; VII CLEAVES; BACTERIOPHAGE-T7; PURIFICATION AB Endonuclease I is a multipurpose enzyme implicated in the breakdown of host DNA, packaging of phage DNA, and recombination during the lytic cycle of bacteriophage T7. We investigate here some aspects of the substate requirements for its activity in resolving branched intermediates similar to Holliday junctions (Holliday, R. (1964) Genet. Res. 5, 282-304) that arise in recombination. The enzyme is able to resolve branched substrates containing very short duplex arms: 4 base pairs suffice. It cleaves 5' to the branch, with a distinct preference for the non-crossover strands in Holliday-like model junctions. Ligands that interact strongly with the branch site can inhibit the enzyme, with K(I) values in the 10-50-mu-M range. C1 NYU,DEPT CHEM,NEW YORK,NY 10003. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. FU NCI NIH HHS [CA-24101]; NIGMS NIH HHS [GM-29554] NR 41 TC 14 Z9 14 U1 1 U2 1 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 5 PY 1991 VL 266 IS 4 BP 2531 EP 2536 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EV515 UT WOS:A1991EV51500079 PM 1990002 ER PT J AU TONG, L DEVOS, AM MILBURN, MV KIM, SH AF TONG, L DEVOS, AM MILBURN, MV KIM, SH TI CRYSTAL-STRUCTURES AT 2.2 A RESOLUTION OF THE CATALYTIC DOMAINS OF NORMAL RAS PROTEIN AND AN ONCOGENIC MUTANT COMPLEXED WITH GDP SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article ID C-HA-RAS; MURINE SARCOMA-VIRUS; BLADDER-CARCINOMA ONCOGENE; P21 TRANSFORMING PROTEIN; ELONGATION-FACTOR-TU; 3-DIMENSIONAL STRUCTURE; NUCLEOTIDE-SEQUENCE; ACTIVATING PROTEIN; BINDING DOMAIN; MECHANISM C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. FU NCI NIH HHS [CA 45593] NR 63 TC 224 Z9 226 U1 0 U2 7 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 5 PY 1991 VL 217 IS 3 BP 503 EP 516 DI 10.1016/0022-2836(91)90753-S PG 14 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EZ034 UT WOS:A1991EZ03400012 PM 1899707 ER PT J AU HOHIMER, JP HADLEY, GR CRAFT, DC SHIAU, TH SUN, S SCHAUS, CF AF HOHIMER, JP HADLEY, GR CRAFT, DC SHIAU, TH SUN, S SCHAUS, CF TI STABLE-MODE OPERATION OF LEAKY-MODE DIODE-LASER ARRAYS AT HIGH PULSED AND CW CURRENTS SO APPLIED PHYSICS LETTERS LA English DT Article ID HIGH-POWER; ANTIGUIDES AB We report stable pulsed and cw fundamental mode operation for ten-stripe leaky-mode diode laser arrays which use the confinement factor effect for mode control. Lasing occurs in the fundamental mode for pulsed operation (less-than-or-equal-to 1-mu-s) up to 10 x threshold and for cw operation up to 3.4 x threshold. For cw operation, a thermal decoupling of the outer array stripes broadens the far field slightly but does not affect the lasing mode order. Our two-dimensional model of these devices reproduces this decoupling of the outer array stripes when thermal effects are included. C1 UNIV NEW MEXICO,CTR HIGH TECHNOL MAT,ALBUQUERQUE,NM 87131. RP HOHIMER, JP (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 13 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 4 PY 1991 VL 58 IS 5 BP 452 EP 454 DI 10.1063/1.104604 PG 3 WC Physics, Applied SC Physics GA EW477 UT WOS:A1991EW47700007 ER PT J AU CRANDALL, RS BALBERG, I AF CRANDALL, RS BALBERG, I TI MOBILITY-LIFETIME PRODUCTS IN HYDROGENATED AMORPHOUS-SILICON SO APPLIED PHYSICS LETTERS LA English DT Article ID A-SI-H; PHOTOCONDUCTIVITY AB The most important parameters characterizing the photoelectronic quality of a semiconductor are its charge-carrier mobility lifetime, mu-tau, products. The two common experimental methods used to determine these parameters in hydrogenated amorphous silicon, alpha-Si:H, are the steady-state photoconductivity measurement and the life-of-flight charge-collection measurement. The two methods yield quite different results. We show that the difference can be resolved by an understanding of the physics involved in each of the measurements. We show that the steady-state-mu-tau-is expected to be up to three orders of magnitude larger than the time-of-flight-mu-tau in undoped-alpha-Si:H. This prediction is in excellent agreement with the corresponding experimental results. C1 HEBREW UNIV JERUSALEM,RACAH INST PHYS,IL-91904 JERUSALEM,ISRAEL. RP CRANDALL, RS (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. NR 23 TC 21 Z9 21 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 4 PY 1991 VL 58 IS 5 BP 508 EP 510 DI 10.1063/1.104622 PG 3 WC Physics, Applied SC Physics GA EW477 UT WOS:A1991EW47700026 ER PT J AU ARNOLD, PB KAUFFMAN, RP AF ARNOLD, PB KAUFFMAN, RP TI W AND Z PRODUCTION AT NEXT-TO-LEADING ORDER - FROM LARGE QT TO SMALL SO NUCLEAR PHYSICS B LA English DT Article ID LARGE TRANSVERSE-MOMENTUM; VECTOR BOSON PRODUCTION; HIGH-PT W; PARTON DENSITIES; BACK JETS; QCD; COLLIDERS; PAIR AB CDF is just completing its analysis of the transverse momentum distribution of singly produced W's or Z's. It is important to have the best possible theoretical predictions to compare against experiment across the entire range of transverse momentum q(T). Previously, theoretical predictions to next-to-leading order in alpha-s have been restricted to the low-q(T) and high-q(T) limits. We take the O(alpha-s2) result at large Q(T), the corresponding soft gluon resummation at low q(T), and consistently match them to obtain a result valid to next-to-leading order at all q(T). We present numerical results for W and Z production at square-root S = 630 GeV and 1.8 TeV. Our analysis also provides a new and independent theoretical test of the formalism of resummation in Drell-Yan processes. RP ARNOLD, PB (reprint author), ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439, USA. NR 24 TC 145 Z9 145 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 FEB 4 PY 1991 VL 349 IS 2 BP 381 EP 413 DI 10.1016/0550-3213(91)90330-Z PG 33 WC Physics, Particles & Fields SC Physics GA ET685 UT WOS:A1991ET68500004 ER PT J AU BARDAKCI, K CRESCIMANNO, M HOTES, SA AF BARDAKCI, K CRESCIMANNO, M HOTES, SA TI PARAFERMIONS FROM NON-ABELIAN COSET MODELS SO NUCLEAR PHYSICS B LA English DT Article ID KAC-MOODY ALGEBRA; 2 DIMENSIONS; CONFORMAL-INVARIANCE; FIELD-THEORIES; BOSONIZATION; CONSTRUCTION AB We generalize an earlier work on conformal coset models to the case of non-abelian factor group. Starting with the gauged Wess-Zumino-Witten lagrangian, we derive the associated parafermion fields and deduce their Poisson brackets. We then present an explicit classical realization of these fields in terms of path ordered exponentials of free currents that satisfy an affine Lie algebra. This construction can be viewed as a non-abelian generalization of the standard free field representation of parafermions. Finally, we extend the classical construction to the full quantum mechanical case. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV PHYS,THEORET PHYS GRP,BERKELEY,CA 94720. RP BARDAKCI, K (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 40 TC 16 Z9 16 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 FEB 4 PY 1991 VL 349 IS 2 BP 439 EP 462 DI 10.1016/0550-3213(91)90332-R PG 24 WC Physics, Particles & Fields SC Physics GA ET685 UT WOS:A1991ET68500006 ER PT J AU BARTLETT, JG HALL, LJ AF BARTLETT, JG HALL, LJ TI CLOSED BARYONIC UNIVERSE FROM PHOTON COOLING SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRINO BURST; SN1987A AB The Universe may be critically closed by baryons and not conflict with standard big-bang nucleosynthesis if the comoving number density of photons is reduced after nucleosynthesis. This is accomplished at a temperature of order 10 keV by recoupling the photons to a cold hidden sector via a photon-mixing mechanism. Signatures from supernovae, neutrino backgrounds, and nucleosynthesis are discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV PHYS,THEORET PHYS GRP,BERKELEY,CA 94720. RP BARTLETT, JG (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 12 TC 16 Z9 16 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 4 PY 1991 VL 66 IS 5 BP 541 EP 544 DI 10.1103/PhysRevLett.66.541 PG 4 WC Physics, Multidisciplinary SC Physics GA EV897 UT WOS:A1991EV89700006 ER PT J AU BLUMENFELD, Y COLONNA, N ROUSSELCHOMAZ, P DELIS, DN HANOLD, K MENG, JC PEASLEE, GF SUI, QC WOZNIAK, GJ MORETTO, LG LIBBY, B MIGNEREY, AC GUARINO, G SANTORUVO, N IORI, I AF BLUMENFELD, Y COLONNA, N ROUSSELCHOMAZ, P DELIS, DN HANOLD, K MENG, JC PEASLEE, GF SUI, QC WOZNIAK, GJ MORETTO, LG LIBBY, B MIGNEREY, AC GUARINO, G SANTORUVO, N IORI, I TI MULTIFRAGMENT EVENTS FROM HEAVY-ION COLLISIONS - SOURCES AND EXCITATION-FUNCTIONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID COMPLEX-FRAGMENT EMISSION AB Multifragment events from 35, 40, 45, and 55 MeV/nucleon La-139 + C-12, Al-27, Ca-40, V-51, (nat)Cu, and La-139 reactions can be assigned to sources characterized by their velocity. At each bombarding energy, the probabilities of threefold, fourfold, and fivefold events increase substantially with decreasing source velocity, but are independent of the target mass. To remove the bombarding-energy dependence, a simple transformation has been applied which gives the excitation energy of the fused system in the simple incomplete-fusion picture. These "excitation functions" appear to be independent of both the system and bombarding energy. C1 UNIV MARYLAND,DEPT CHEM,COLLEGE PK,MD 20742. INST NAZL FIS NUCL,I-70126 BARI,ITALY. UNIV MILAN,I-20133 MILAN,ITALY. RP BLUMENFELD, Y (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. RI Mignerey, Alice/D-6623-2011 NR 16 TC 55 Z9 55 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 4 PY 1991 VL 66 IS 5 BP 576 EP 579 DI 10.1103/PhysRevLett.66.576 PG 4 WC Physics, Multidisciplinary SC Physics GA EV897 UT WOS:A1991EV89700015 ER PT J AU CHMELKA, BF RAFTERY, D MCCORMICK, AV DEMENORVAL, LC LEVINE, RD PINES, A AF CHMELKA, BF RAFTERY, D MCCORMICK, AV DEMENORVAL, LC LEVINE, RD PINES, A TI MEASUREMENT OF XENON DISTRIBUTION STATISTICS IN NA-A ZEOLITE CAVITIES SO PHYSICAL REVIEW LETTERS LA English DT Article ID LATTICE GAS-MODEL; PROBABILITY-DISTRIBUTION; MOLECULAR-DYNAMICS; SIMULATIONS; ADSORPTION; FLUIDS AB Xe-129 NMR spectroscopy has been used to probe directly the distribution of xenon atoms confined in atomic-size Na-A zeolite cavities. For mean xenon occupancies less than about three Xe atoms per a-cage, the guest populations are well described by binomial statistics. At higher guest loadings the finite volumes of the xenon atoms become significant, as reflected by a fit of the experimental populations with a hypergeometric distribution, with a maximum of seven Xe atoms per cage. At the highest xenon loadings the experimental distribution is narrower than hypergeometric, as predicted by Monte Carlo simulations. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. RP CHMELKA, BF (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. NR 21 TC 82 Z9 82 U1 2 U2 14 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 4 PY 1991 VL 66 IS 5 BP 580 EP 583 DI 10.1103/PhysRevLett.66.580 PG 4 WC Physics, Multidisciplinary SC Physics GA EV897 UT WOS:A1991EV89700016 ER PT J AU RAFTERY, D LONG, H MEERSMANN, T GRANDINETTI, PJ REVEN, L PINES, A AF RAFTERY, D LONG, H MEERSMANN, T GRANDINETTI, PJ REVEN, L PINES, A TI HIGH-FIELD NMR OF ADSORBED XENON POLARIZED BY LASER PUMPING SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEAR-SPIN RELAXATION; XE-129 NMR; MOLECULAR-SIEVES; CHEMICAL-SHIFT; GAS; SPECTROSCOPY; ANISOTROPY; EXCHANGE; SURFACES; SOLIDS AB Optical pumping has been used to enhance the pulsed NMR signal of Xe-129, allowing the detection of low-pressure xenon gas and of xenon adsorbed on powdered solids. We observe an increase in sensitivity of more than 2 orders of magnitude over conventional NMR, the current limitation being the laser power. Adsorbed xenon is observed at 298 K on graphitized carbon (10 m2/g) and on powdered benzanthracene (approximately 0.5 m2/g) below 170 K. The increased sensitivity of this technique allows the study of a large class of amorphous materials with surface areas below 10 m2/g including semiconductors, polymers, metal oxides, and catalysts. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP RAFTERY, D (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720, USA. RI Reven, Linda/F-3679-2011; Grandinetti, Philip/F-1084-2010 OI Grandinetti, Philip/0000-0003-0102-316X NR 35 TC 225 Z9 228 U1 3 U2 19 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 4 PY 1991 VL 66 IS 5 BP 584 EP 587 DI 10.1103/PhysRevLett.66.584 PG 4 WC Physics, Multidisciplinary SC Physics GA EV897 UT WOS:A1991EV89700017 ER PT J AU SANYAL, MK SINHA, SK HUANG, KG OCKO, BM AF SANYAL, MK SINHA, SK HUANG, KG OCKO, BM TI X-RAY-SCATTERING STUDY OF CAPILLARY-WAVE FLUCTUATIONS AT A LIQUID SURFACE SO PHYSICAL REVIEW LETTERS LA English DT Article ID REFLECTIVITY; DIFFRACTION; GRAPHITE; SYSTEM AB A study of the scattering of x rays from the liquid-vapor interface of ethanol at room temperature is reported and compared in detail to predictions based on standard continuum capillary-wave theory. Quantitative agreement is obtained and, in particular, the asymptotic power laws in the diffuse scattering characteristic of the algebraic decay of the density-fluctuation correlations at the surface are verified. The root-mean-square fluctuation of the liquid surface is obtained as 6.9 +/- 0.2 angstrom. C1 EXXON RES & ENGN CO,CORP RES LAB,ANNANDALE,NJ 08801. RP SANYAL, MK (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. RI sanyal, milan/J-2527-2015 OI sanyal, milan/0000-0002-3847-8793 NR 21 TC 247 Z9 248 U1 1 U2 25 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 4 PY 1991 VL 66 IS 5 BP 628 EP 631 DI 10.1103/PhysRevLett.66.628 PG 4 WC Physics, Multidisciplinary SC Physics GA EV897 UT WOS:A1991EV89700028 ER PT J AU DUONGVAN, M AF DUONGVAN, M TI TIME DOMAINS OF 1/F AND WHITE-NOISE FLUCTUATIONS SO PHYSICS LETTERS A LA English DT Article AB We investigate the two types of stochastic features of the solution of the differential equation d2x/dt2 - (1/tau)dx/dt + (theta-0/tau)2xe2t/tau = 0. The solution x(t) of this equation, when evaluated at multiples of the time interval DELTA-t = tau, generates the random sequences x(n) of the logistic map x(n+1) = 4x(n)(1 - x(n)) with a white power spectrum. When time is treated as continuous, however, the power spectrum is essentially 1/f. A connection between the logistic map and the Weierstrass-Mandelbrot function is also made. RP DUONGVAN, M (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT PHYS,LIVERMORE,CA 94550, USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD FEB 4 PY 1991 VL 152 IS 8 BP 397 EP 400 DI 10.1016/0375-9601(91)90832-S PG 4 WC Physics, Multidisciplinary SC Physics GA EZ990 UT WOS:A1991EZ99000005 ER PT J AU REID, SA MCJANNET, GS AF REID, SA MCJANNET, GS TI INFLUENCE OF ANTICLINAL GROWTH ON UPPER MIOCENE TURBIDITE DEPOSITS, ELK HILLS FIELD, KERN COUNTY, CALIFORNIA SO AAPG BULLETIN-AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS LA English DT Meeting Abstract C1 BECHTEL PETR OPERAT INC,TUPMAN,CA. US DOE,TUPMAN,CA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER ASSN PETROL GEOLOGISTS PI TULSA PA 1444 S BOULDER AVE PO BOX 979, TULSA, OK 74101 SN 0149-1423 J9 AAPG BULL JI AAPG Bull.-Am. Assoc. Petr. Geol. PD FEB PY 1991 VL 75 IS 2 BP 378 EP 378 PG 1 WC Energy & Fuels; Engineering, Petroleum; Geosciences, Multidisciplinary SC Energy & Fuels; Engineering; Geology GA EZ450 UT WOS:A1991EZ45000112 ER PT J AU WILSON, M LOVE, C FISHBURN, M HUMPHREY, M AF WILSON, M LOVE, C FISHBURN, M HUMPHREY, M TI THE USE OF WIRELINE PRESSURE MEASUREMENTS TO REFINE RESERVOIR DESCRIPTION, MAIN BODY B WATERFLOOD, ELK HILLS OIL-FIELD, KERN COUNTY, CALIFORNIA SO AAPG BULLETIN-AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS LA English DT Meeting Abstract C1 BECHTEL PETR OPERAT INC,TUPMAN,CA. SCI SOFTWARE INTERCOMP INC,BAKERSFIELD,CA. US DOE,LOS ANGELES,CA. CHEVRON USA INC,SAN RAMON,CA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER ASSN PETROL GEOLOGISTS PI TULSA PA 1444 S BOULDER AVE PO BOX 979, TULSA, OK 74101 SN 0149-1423 J9 AAPG BULL JI AAPG Bull.-Am. Assoc. Petr. Geol. PD FEB PY 1991 VL 75 IS 2 BP 386 EP 386 PG 1 WC Geosciences, Multidisciplinary SC Geology GA EZ450 UT WOS:A1991EZ45000146 ER PT J AU THIEL, PA AF THIEL, PA TI NEW CHEMICAL MANIFESTATIONS OF HYDROGEN-BONDING IN WATER ADLAYERS SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID RU(001); ADSORPTION; DESORPTION; H2O; CLUSTER; SURFACE C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP THIEL, PA (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011, USA. NR 27 TC 12 Z9 12 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD FEB PY 1991 VL 24 IS 2 BP 31 EP 35 DI 10.1021/ar00002a001 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA EX584 UT WOS:A1991EX58400001 ER PT J AU WEBER, HP CRAVEN, BM SAWZIK, P MCMULLAN, RK AF WEBER, HP CRAVEN, BM SAWZIK, P MCMULLAN, RK TI CRYSTAL-STRUCTURE AND THERMAL VIBRATIONS OF CHOLESTERYL ACETATE FROM NEUTRON-DIFFRACTION AT 123-K AND 20-K SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID MOTION AB Cholesteryl acetate (C29H48O2) at 20 K is monoclinic, space group P2(1) with a = 16.521 (4), b = 9.220 (2), c = 17.620 (5) angstrom, beta = 107.18 (2)-degrees and Z = 4 (two molecules in the asymmetric unit). The crystal structure, earlier determined by X-ray diffraction at 123 K, has been redetermined at 123 and 20 K by neutron diffraction (7447 reflections at 123 K, 7281 at 20 K; sin theta/lambda < 0.69 angstrom-1) and refined by full-matrix least squares with 1423 variables to give R(F2) = 0.10 at 123 K, 0.06 at 20 K. Results at 20 K are more accurate not only because nuclear thermal vibrations have reduced amplitudes but also because a larger crystal was used for data collection. At 20 K, the average of 44 methylene C-H bond lengths is 1.102(8) angstrom (sigma from the observed distribution) and 1.103 (6) angstrom for 16 methine groups. The 22 methylene H-C-H angles [106.2 (9)-degrees] all fall within a narrow range. Analysis of nuclear anisotropic thermal parameters shows that intramolecular vibrations of the H nuclei are highly significant with similar meansquare amplitudes at 123 and 20 K. Torsional vibrations around the C-CH3 bonds of the C18 and C19 methyl groups have r.m.s. amplitudes of about 7-degrees. For methylene groups, mean-square amplitudes are a minimum for C-H bond stretching (0.006 angstrom 2) and a maximum for CH2 in-plane vibrations (0.024 angstrom 2). Values of B(eq) for the H-atom intramolecular vibrations are 0.8, 1.2 and 1.6 angstrom 2 for methine, methylene and methyl H atoms respectively. These results can be used to estimate B(eq) for H atoms in crystal structure determinations carried out by X-ray diffraction. The anisotropic intramolecular vibrations of the H nuclei contribute to the effective shape of the H atoms which, from the observed anisotropy in the distribution of intermolecular H...H distances, appears to be flattened along the direction of the C-H bond. C1 UNIV PITTSBURGH,DEPT CRYSTALLOG,PITTSBURGH,PA 15260. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. FU NHLBI NIH HHS [HL-20350] NR 23 TC 37 Z9 37 U1 0 U2 0 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 1991 VL 47 BP 116 EP 127 DI 10.1107/S0108768190009739 PN 1 PG 12 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA EW613 UT WOS:A1991EW61300016 PM 2025409 ER PT J AU JASTROW, JD MILLER, RM AF JASTROW, JD MILLER, RM TI METHODS FOR ASSESSING THE EFFECTS OF BIOTA ON SOIL STRUCTURE SO AGRICULTURE ECOSYSTEMS & ENVIRONMENT LA English DT Article; Proceedings Paper CT WORKSHOP ON MODERN TECHNIQUES IN SOIL ECOLOGY CY SEP 11-15, 1989 CL ATLANTA, GA SP FRANKLIN COLL ARTS & SCI, UNIV GEORGIA RES FDN, UNIV GEORGIA, DEPT AGRON, UNIV GEORGIA, DEPT ENTOMOL, UNIV GEORGIA, INST ECOL, OHIO STATE UNIV, DEPT ENTOMOL, US AGCY INT DEV, SO MICRO INSTRUMENTS, GREEN GLEN ID AGGREGATE STABILITY; ORGANIC-MATTER; CHARACTERIZING MACROPORES; IMAGE-ANALYSIS; SPRING WHEAT; WATER; CULTIVATION; MANAGEMENT; PERIODATE; CROP AB Soil biota participate in the genesis of the habitat wherein they live. Together with climate, topography, parent material, and time, vegetation and soil organisms comprise one of Jenny's five interactive soil-forming factors. Only recently has a conceptual framework for investigating the interrelationships of soil biota with soil structure been outlined. This view of soil emphasizes the hierarchical nature of soil structure, which transcends at least four orders of magnitude. Because of the feedback relationship between biota and the development of soil structure, methods of quantifying soil structure will differ with the question being asked. This review briefly considers various methods that have been used to assess the effects of biota, their by-products, and their activities on soil structure. Included are methods tied to the mechanical separation of aggregates, the quantification of pore space, and the evaluation of soil microenvironments using soil micromorphology techniques. Also discussed are important considerations for the sampling, preparation, and application of generally accepted basic methods for quantifying aggregate size distributions and stability. Lastly, a demonstration is presented of how a conceptual framework can be coupled with the use of path-analysis techniques to provide a means for determining the relative importance of various biotic factors in the development of soil structure. RP JASTROW, JD (reprint author), ARGONNE NATL LAB,DIV ENVIRONM RES,ARGONNE,IL 60439, USA. NR 99 TC 62 Z9 66 U1 1 U2 20 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-8809 J9 AGR ECOSYST ENVIRON JI Agric. Ecosyst. Environ. PD FEB PY 1991 VL 34 IS 1-4 BP 279 EP 303 DI 10.1016/0167-8809(91)90115-E PG 25 WC Agriculture, Multidisciplinary; Ecology; Environmental Sciences SC Agriculture; Environmental Sciences & Ecology GA FD132 UT WOS:A1991FD13200027 ER PT J AU REDA, DC AF REDA, DC TI OBSERVATIONS OF DYNAMIC STALL PHENOMENA USING LIQUID-CRYSTAL COATINGS SO AIAA JOURNAL LA English DT Note C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. NR 11 TC 9 Z9 9 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 1991 VL 29 IS 2 BP 308 EP 310 DI 10.2514/3.59918 PG 3 WC Engineering, Aerospace SC Engineering GA FA441 UT WOS:A1991FA44100020 ER PT J AU TATTERSON, GB KYSER, EA AF TATTERSON, GB KYSER, EA TI MIXING IN FED-BATCH AND CONTINUOUS-FLOW PROCESSES IN NONSTANDARD GEOMETRIES SO AICHE JOURNAL LA English DT Note ID TIME C1 SAVANNAH RIVER ECOL LAB,ACTINIDE TECHNOL SECT,AIKEN,SC 29808. RP TATTERSON, GB (reprint author), N CAROLINA AGR & TECHNOL STATE UNIV,DEPT CHEM ENGN,GREENSBORO,NC 27411, USA. NR 23 TC 3 Z9 3 U1 1 U2 3 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 1991 VL 37 IS 2 BP 269 EP 273 DI 10.1002/aic.690370213 PG 5 WC Engineering, Chemical SC Engineering GA EX550 UT WOS:A1991EX55000012 ER PT J AU LAYNE, SP MERGES, MJ DEMBO, M SPOUGE, JL GELDERBLOM, HR NARA, PL AF LAYNE, SP MERGES, MJ DEMBO, M SPOUGE, JL GELDERBLOM, HR NARA, PL TI DETERMINING BASIC MOLECULAR REQUIREMENTS FOR BLOCKING THERAPIES AND HIV VACCINES INVITRO SO AIDS RESEARCH AND HUMAN RETROVIRUSES LA English DT Meeting Abstract C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NCI,FREDERICK,MD 21701. NATL LIB MED,BETHESDA,MD 20892. ROBERT KOCH INST,W-1000 BERLIN 65,GERMANY. RI Dembo, Micah/C-2755-2013 NR 0 TC 0 Z9 0 U1 0 U2 2 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 SN 0889-2229 J9 AIDS RES HUM RETROV JI Aids Res. Hum. Retrovir. PD FEB PY 1991 VL 7 IS 2 BP 210 EP 211 PG 2 WC Immunology; Infectious Diseases; Virology SC Immunology; Infectious Diseases; Virology GA EY300 UT WOS:A1991EY30000156 ER PT J AU EAGAN, RJ AF EAGAN, RJ TI IN TUNE WITH THE TIMES SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Editorial Material C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP EAGAN, RJ (reprint author), AMER CERAM SOC INC,757 BROOKSEDGE PLAZA DR,WESTERVILLE,OH 43081, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7812 J9 AM CERAM SOC BULL JI Am. Ceram. Soc. Bull. PD FEB PY 1991 VL 70 IS 2 BP 157 EP 157 PG 1 WC Materials Science, Ceramics SC Materials Science GA FC775 UT WOS:A1991FC77500001 ER PT J AU DAS, S CURLEE, TR AF DAS, S CURLEE, TR TI ADVANCED MATERIALS INFORMATION NEEDS - A SURVEY REPORT SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Article RP DAS, S (reprint author), OAK RIDGE NATL LAB,ENERGY & ECON ANAL SECT,OAK RIDGE,TN 37831, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7812 J9 AM CERAM SOC BULL JI Am. Ceram. Soc. Bull. PD FEB PY 1991 VL 70 IS 2 BP 234 EP 239 PG 6 WC Materials Science, Ceramics SC Materials Science GA FC775 UT WOS:A1991FC77500014 ER PT J AU EGAN, CB SMITH, FG HOUK, RS SERFASS, RE AF EGAN, CB SMITH, FG HOUK, RS SERFASS, RE TI ZINC-ABSORPTION IN WOMEN - COMPARISON OF INTRINSIC AND EXTRINSIC STABLE-ISOTOPE LABELS SO AMERICAN JOURNAL OF CLINICAL NUTRITION LA English DT Article DE ZINC ABSORPTION; STABLE ISOTOPES; INTRINSIC LABEL; EXTRINSIC LABEL; HUMAN SUBJECTS ID PROTEIN-SOURCE; YOUNG MEN; BIOAVAILABILITY; HUMANS; MILK; RATS AB Fractional absorption of extrinsic and intrinsic zinc from milk-based formulated diets was measured in 10 young women by using a simultaneous triple-isotope method based on fecal monitoring of unabsorbed enriched stable-isotope labels. Zinc intake was held nearly constant (xBAR zinc intake = 1.48-mu-mol.kg body wt-1.d-1) throughout the 18-d controlled feeding phase of the study by addition of extrinsic Zn-64 to all formula feedings, with substitution of the extrinsic Zn-67 label for some of the Zn-64 when formula intrinsically labeled with Zn-70 was given. Fractional absorption values of intrinsic and extrinsic zinc labels, 0.267 +/- 0.092 (xBAR +/- SD) and 0.282 +/- 0.086, respectively, were highly correlated (r = 0.83, P < 0.05) and did not differ significantly. The ratio of fractional absorption of the extrinsic to that of the intrinsic label, 1.08 +/- 0.20 (xBAR +/- SD), was not significantly different from unity. The results show that extrinsic labeling by use of enriched stable isotopes is a valid means of determining zinc absorption from milk-based diets in adult humans. C1 US DOE,AMES LAB,DEPT FOOD SCI & HUMAN NUTR,AMES,IA. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 27 TC 35 Z9 35 U1 0 U2 2 PU AMER SOC CLIN NUTRITION INC PI BETHESDA PA 9650 ROCKVILLE PIKE SUBSCRIPTIONS, RM L-2310, BETHESDA, MD 20814-3998 SN 0002-9165 J9 AM J CLIN NUTR JI Am. J. Clin. Nutr. PD FEB PY 1991 VL 53 IS 2 BP 547 EP 553 PG 7 WC Nutrition & Dietetics SC Nutrition & Dietetics GA EU946 UT WOS:A1991EU94600025 PM 1989425 ER PT J AU NOGUCHI, CT MOHANDAS, N BLANCHETTEMACKIE, J MACKIE, S RAIK, E CHARACHE, S AF NOGUCHI, CT MOHANDAS, N BLANCHETTEMACKIE, J MACKIE, S RAIK, E CHARACHE, S TI HEMOGLOBIN AGGREGATION AND PSEUDOSICKLING INVITRO OF HEMOGLOBIN SETIF-CONTAINING ERYTHROCYTES SO AMERICAN JOURNAL OF HEMATOLOGY LA English DT Article DE ERYTHROCYTE DEFORMABILITY; ABNORMAL ERYTHROCYTES; HEMOGLOBIN ID SICKLE HEMOGLOBIN; ASP-> TYR; HB SETIF; POLYMERIZATION; GELATION; FAMILY AB Erythrocytes from individuals heterozygous for hemoglobin Setif (alpha-94 Asp --> Tyr) sickle in vitro without deoxygenation when incubated in chloride buffer due to hemoglobin aggregation. We now report quantitative studies of hemoglobin polymerization and deformability in these cells. Hemoglobin polymer gradually increased in intact cells during a 24 h incubation period at 24-degrees-C. After 24 hr, about 80% of the cells in 290 mOsm sodium chloride buffer contained polymer which appeared as short rods compared to > 99% containing polymer at 450 mOsm. Similar proportions of cells were morphologically sickled. Deformability of erythrocytes with 40% hemoglobin Setif incubated in 290 mOsm buffer at 37-degrees-C decreased to 80% of normal by 210 min but in 450 mOsm decreased to 50% after only 30 min as measured by the ektacytometer. However, at 4-degrees-C deformability remained normal even in 450 mOsm buffer. The solubility of gelled hemolysate containing 40% hemoglobin Setif was 24 g/dl and 21 g/dl at 290 and 459 mOsm buffer respectively. The gel persisted at 4-degrees-C with a solubility of 26 g/dl, but melted when dialyzed into sodium phosphate or potassium phosphate buffer. These data suggest that hemoglobin polymerization, reduced deformability, and sickling of hemoglobin Setif-containing erythrocytes are related to reduced hemoglobin solubility. The rate and extent of intracellular polymerization in vitro are considerably reduced (as in the case of sickle trait) compared with erythrocytes from individuals with sickle cell anemia. Hence, the slower kinetics of hemoglobin aggregation in hemoglobin Setif-containing cells provide an alternate system for studying hemoglobin polymerization and abnormal rheology. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. SYDNEY HOSP,SYDNEY,NSW 2000,AUSTRALIA. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. RP NOGUCHI, CT (reprint author), NIDDKD,BLDG 10,ROOM 9N307,BETHESDA,MD 20892, USA. FU NHLBI NIH HHS [HL31579] NR 28 TC 1 Z9 1 U1 0 U2 1 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0361-8609 J9 AM J HEMATOL JI Am. J. Hematol. PD FEB PY 1991 VL 36 IS 2 BP 131 EP 139 DI 10.1002/ajh.2830360212 PG 9 WC Hematology SC Hematology GA EX558 UT WOS:A1991EX55800010 PM 2012063 ER PT J AU MEYER, SA MORGENSTERN, MA KNUDSON, SK NOID, DW AF MEYER, SA MORGENSTERN, MA KNUDSON, SK NOID, DW TI NOVEL METHOD FOR WKB ANALYSIS OF MULTIDIMENSIONAL SYSTEMS SO AMERICAN JOURNAL OF PHYSICS LA English DT Article ID SEMICLASSICAL CALCULATION; EIGENVALUES; SURFACE; SECTION AB The availability of powerful microcomputers with graphics capabilities expands the range of numerical procedures that can be employed for undergraduate use. The use of simple software packages for the evaluation of multidimensional WKB approximate eigenvalues is discussed. Introductory courses in quantum mechanics rarely make use of semiclassical theories, such as WKB, to relate quantum mechanics to classical mechanics. This relationship can be helpful for the student's understanding of quantum mechanics, and a computer experiment can provide a useful avenue for making the concepts concrete. The major components of the approach involve the use of a package for the integration of differential equations, to treat the classical equations of motion, and a computer-aided design package to determine the phase integral areas. The codes are not expensive, and all exploit the graphical capabilities of microcomputers, which are critical for visualizing the relationship between classical and quantum ideas. C1 COLL WILLIAM & MARY,DEPT CHEM,WILLIAMSBURG,VA 23185. OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. RP MEYER, SA (reprint author), COLORADO COLL,DEPT CHEM,COLORADO SPRINGS,CO 80903, USA. NR 21 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD FEB PY 1991 VL 59 IS 2 BP 145 EP 151 DI 10.1119/1.16595 PG 7 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA EU884 UT WOS:A1991EU88400013 ER PT J AU CRAWFORD, FS AF CRAWFORD, FS TI CUBE CORNER RETROREFLECTORS FOR SOUND-WAVES SO AMERICAN JOURNAL OF PHYSICS LA English DT Note C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP CRAWFORD, FS (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD FEB PY 1991 VL 59 IS 2 BP 176 EP 177 DI 10.1119/1.16601 PG 2 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA EU884 UT WOS:A1991EU88400020 ER PT J AU BOWYER, JR ALARIE, JP SEPANIAK, MJ VO-DINH, T THOMPSON, RQ AF BOWYER, JR ALARIE, JP SEPANIAK, MJ VO-DINH, T THOMPSON, RQ TI CONSTRUCTION AND EVALUATION OF A REGENERABLE FLUOROIMMUNOCHEMICAL-BASED FIBER OPTIC BIOSENSOR SO ANALYST LA English DT Article DE FIBER OPTIC; BIOSENSOR; FLUOROIMMUNOASSAY; LASER; IMMUNOGLOBULIN-G ID CHEMICAL SENSORS; FLUORESCENCE; BINDING AB A microscale fibre optic biosensor that is capable of in situ regeneration is described and characterized. By combining recently developed fibre optic sensing technology with a capillary column reagent delivery system, it is possible to perform a variety of bench-top affinity assay procedures both repetitively and remotely. The configuration of the sensing chamber at the terminus of the fibre is an important design feature. The construction and operation of the sensor is described and the results of evaluations of the sensor using an antibody-antigen system are presented. Affinity assay steps such as the delivery of solid phase affinity reagents, secondary reagents and rinse solutions are demonstrated. Sampling is accomplished by mild aspiration. Relative standard deviations (RSDs) for these steps are all less than 10%. The capability of selectively measuring fluorescently labelled anti-rabbit immunoglobulin G (lgG), in the presence of a similar protein, by utilizing its immunospecific interaction with rabbit lgG immobilized on silica beads is demonstrated, and exhibits an RSD of 6.2%. A near linear calibration graph is presented over a concentration range of between 0.011 (approximately the limit of detection) and 0.11 mg ml-1. C1 UNIV TENNESSEE, DEPT CHEM, KNOXVILLE, TN 37996 USA. OAK RIDGE NATL LAB, DIV HLTH & SAFETY RES, OAK RIDGE, TN 37831 USA. OBERLIN COLL, DEPT CHEM, OBERLIN, OH 44074 USA. NR 30 TC 12 Z9 12 U1 1 U2 2 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0003-2654 EI 1364-5528 J9 ANALYST JI Analyst PD FEB PY 1991 VL 116 IS 2 BP 117 EP 122 DI 10.1039/an9911600117 PG 6 WC Chemistry, Analytical SC Chemistry GA EY470 UT WOS:A1991EY47000001 ER PT J AU PETERSON, DP HUFF, EA BHATTACHARYYA, MH AF PETERSON, DP HUFF, EA BHATTACHARYYA, MH TI DETERMINATION OF CADMIUM IN BLOOD, PLASMA, AND URINE BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROPHOTOMETRY AFTER ISOLATION BY ANION-EXCHANGE CHROMATOGRAPHY SO ANALYTICAL BIOCHEMISTRY LA English DT Article ID SPECTROMETRY C1 ARGONNE NATL LAB,DIV CHEM TECHNOL,ARGONNE,IL 60439. RP PETERSON, DP (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439, USA. FU NIEHS NIH HHS [ES-04816] NR 12 TC 10 Z9 10 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 0003-2697 J9 ANAL BIOCHEM JI Anal. Biochem. PD FEB 1 PY 1991 VL 192 IS 2 BP 434 EP 440 DI 10.1016/0003-2697(91)90561-7 PG 7 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA EW647 UT WOS:A1991EW64700029 PM 2035842 ER PT J AU ZHANG, L CARNAHAN, JW WINANS, RE NEILL, PH AF ZHANG, L CARNAHAN, JW WINANS, RE NEILL, PH TI SUPERCRITICAL FLUID CHROMATOGRAPHY WITH A HELIUM MICROWAVE-INDUCED PLASMA FOR CHLORINE-SELECTIVE DETECTION SO ANALYTICAL CHEMISTRY LA English DT Article ID PRESSURE AB A helium microwave-induced plasma was coupled directly to a capillary supercritical fluid chromatograph. Carbon dioxide was utilized as the mobile phase. The chromatographic system, interface, and plasma source are described. For the determination of chlorine, the near-infrared atomic emission line at 837.6 nm was chosen to avoid molecular emission band interferences in the visible spectral region. Signal intensity reduction was observed with increased supercritical fluid chromatography mobile-phase pressure. Chromatograms for mixtures of chlorine-containing compounds are illustrated. The calibration range was 3 orders of magnitude, and the chlorine detection limit was 40 pg/s. C1 NO ILLINOIS UNIV,DEPT CHEM,DE KALB,IL 60115. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. NR 21 TC 23 Z9 23 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 1991 VL 63 IS 3 BP 212 EP 216 DI 10.1021/ac00003a005 PG 5 WC Chemistry, Analytical SC Chemistry GA EV495 UT WOS:A1991EV49500006 ER PT J AU WIEDERIN, DR SMITH, FG HOUK, RS AF WIEDERIN, DR SMITH, FG HOUK, RS TI DIRECT INJECTION NEBULIZATION FOR INDUCTIVELY COUPLED PLASMA MASS-SPECTROMETRY SO ANALYTICAL CHEMISTRY LA English DT Article ID LIQUID-CHROMATOGRAPHY; ATOMIC SPECTROSCOPY; SAMPLE INTRODUCTION; INTERFERENCES; SPECIATION AB An improved direct injection nebulizer (DIN) is used in a continuous-flow mode for inductively coupled plasma mass spectrometry (ICP/MS). Precision in cases where the signal is not limited by counting statistics is typically 0.5% relative standard deviation (RSD), an improvement by a factor of 4 over the precision obtained with conventional nebulizers. A rinse-out time of only 15 s is sufficient to reduce the analyte signal to 0.1% of its steady-state value, even for memory-prone elements such as Hg and I. Relative detection limits are similar to those obtained with conventional pneumatic nebulizers. Since the sample flow rate is only 120-mu-L min-1, the absolute detection limits are improved by up to an order of magnitude. The refractory oxide ion ratios (MO+/M+) are 3 times higher than with other nebulizers. Matrix effects caused by Na are comparable to those observed with other nebulizers. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. NR 28 TC 147 Z9 147 U1 1 U2 9 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 1991 VL 63 IS 3 BP 219 EP 225 DI 10.1021/ac00003a007 PG 7 WC Chemistry, Analytical SC Chemistry GA EV495 UT WOS:A1991EV49500008 ER PT J AU FREDRICKSON, JK BALKWILL, DL ZACHARA, JM LI, SMW BROCKMAN, FJ SIMMONS, MA AF FREDRICKSON, JK BALKWILL, DL ZACHARA, JM LI, SMW BROCKMAN, FJ SIMMONS, MA TI PHYSIOLOGICAL DIVERSITY AND DISTRIBUTIONS OF HETEROTROPHIC BACTERIA IN DEEP CRETACEOUS SEDIMENTS OF THE ATLANTIC COASTAL-PLAIN SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SATURATED GROUNDWATER ENVIRONMENT; SAVANNAH RIVER PLANT; SUBSURFACE SEDIMENTS; TERRESTRIAL SUBSURFACE; SOUTH-CAROLINA; MICROBIAL COMMUNITIES; AQUIFER; DENITRIFICATION; BIODEGRADATION; SAND AB A series of 23 intact core segments was obtained from two distinct deep subsurface geological formations, the Middendorf and the Cape Fear formations, underlying the southeastern coastal plain of South Carolina. The Middendorf formation in this region consists of permeable, saturated, sandy sediments; the Cape Fear formation consists mainly of less permeable sediments. The core segments were separated by vertical distances ranging from several centimeters to 48 m. Aerobic chemoheterotrophic bacteria were enumerated on a dilute medium, and populations ranged from 3.1 to 6.4 log CFU g of sediment-1 in the Middendorf cores and from below detection to 4.3 log CFU g-1 in the Cape Fear cores. A total of 198 morphologically distinct colony types were isolated, purified, and subjected to 108 different physiological measurements. The isolates from the two formations were distinct (i.e., they produced substantially different response patterns to the various physiological measurements), as were those in different core samples, from the same formation. Cluster analysis revealed 21 different biotypes based on similarities of 75% or higher in response patterns to 21 physiological assays. One biotype contained 57 (29%) of the subsurface isolates, 10 biotypes contained 5 or more isolates, and the remainder had 4 or fewer. The organic compounds that were most commonly metabolized by the subsurface bacteria included Tween 40 (85%) and beta-hydroxybutyric acid (60%). Organic acids, in general, were also commonly metabolized by the subsurface bacteria. Isolates from the Cape Fear core segments were capable of metabolizing a higher percentage of the substrates than were bacteria isolated from the Middendorf formation. Although the heterogeneous distributions of bacteria in deep subsurface sediments may make it difficult to use aquifer microcosms to predict in situ biotransformation rates, the diversity of the physiological properties of these organisms offers promise for in situ remediation of contaminants. C1 FLORIDA STATE UNIV, DEPT BIOL SCI, TALLAHASSEE, FL 32306 USA. RP FREDRICKSON, JK (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 31 TC 124 Z9 129 U1 0 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1325 MASSACHUSETTS AVENUE, NW, WASHINGTON, DC 20005-4171 SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD FEB PY 1991 VL 57 IS 2 BP 402 EP 411 PG 10 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA EV647 UT WOS:A1991EV64700011 PM 16348407 ER PT J AU LAGORY, KE BAGSHAW, C BRISBIN, IL AF LAGORY, KE BAGSHAW, C BRISBIN, IL TI NICHE DIFFERENCES BETWEEN MALE AND FEMALE WHITE-TAILED DEER ON OSSABAW-ISLAND, GEORGIA SO APPLIED ANIMAL BEHAVIOUR SCIENCE LA English DT Article; Proceedings Paper CT CONF ON UNGULATE BEHAVIOR AND MANAGEMENT CY MAY 23-27, 1988 CL TEXAS A & M UNIV, COLLEGE STN, TX SP DALLAS ECOLOG FDN, DALLAS SAFARI CLUB, EXOT WILDLIFE ASSOC, GERALDINE R DODGE FDN, INT ANIM EXCHANGE, ROB & BESSIE WELDER WILDLIFE FDN, US FISH & WILDLIFE SERV, WESLEY KYLE, TEXAS A&M UNIV, DEPT WILDLIFE & FISHERIES SCI HO TEXAS A & M UNIV ID CERVUS-ELAPHUS; CHEMICAL-ANALYSIS; SEX-DIFFERENCES; RUMEN CONTENTS; BIGHORN SHEEP; FOOD QUALITY; MULE DEER; HABITAT; DIGESTIBILITY; SEGREGATION AB Niche differences between male and female white-tailed deer (Odocoileus virginianus) were studied on Ossabaw Island, Georgia, U.S.A. Most deer seen in pastures were males, but males and females were seen in approximately equal numbers in forest habitat. Pastures contained more abundant and apparently higher quality forage than did forest habitat. The use of higher quality areas by males is not consistent with observations of most other ungulate species. Resource limitation and the relatively high population density of deer on Ossabaw Island may have contributed to this pattern of habitat use. No dietary differences between the sexes were observed within habitats, as indicated by a lack of significant differences in rumen contents, in vitro digestion of forages, and foraging behavior. C1 UNIV GEORGIA,SAVANNAH RIVER ECOL LAB,AIKEN,SC 29801. RP LAGORY, KE (reprint author), ARGONNE NATL LAB,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 25 TC 20 Z9 20 U1 3 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1591 J9 APPL ANIM BEHAV SCI JI Appl. Anim. Behav. Sci. PD FEB PY 1991 VL 29 IS 1-4 BP 205 EP 214 DI 10.1016/0168-1591(91)90248-V PG 10 WC Agriculture, Dairy & Animal Science; Behavioral Sciences; Veterinary Sciences SC Agriculture; Behavioral Sciences; Veterinary Sciences GA FE755 UT WOS:A1991FE75500015 ER PT J AU ONEIL, TA WITMER, GW AF ONEIL, TA WITMER, GW TI ASSESSING CUMULATIVE IMPACTS TO ELK AND MULE DEER IN THE SALMON RIVER BASIN, IDAHO SO APPLIED ANIMAL BEHAVIOUR SCIENCE LA English DT Article; Proceedings Paper CT CONF ON UNGULATE BEHAVIOR AND MANAGEMENT CY MAY 23-27, 1988 CL TEXAS A & M UNIV, COLLEGE STN, TX SP DALLAS ECOLOG FDN, DALLAS SAFARI CLUB, EXOT WILDLIFE ASSOC, GERALDINE R DODGE FDN, INT ANIM EXCHANGE, ROB & BESSIE WELDER WILDLIFE FDN, US FISH & WILDLIFE SERV, WESLEY KYLE, TEXAS A&M UNIV, DEPT WILDLIFE & FISHERIES SCI HO TEXAS A & M UNIV AB Elk (Cervus elaphus) and mule deer (Odocoileus hemionus) within the Salmon River Basin are managed by resource agencies to ensure long-term annual returns. These species have similar requirements for forage and cover and are subject to many of the same perturbations from road building, logging, and hydroelectric development. Hence, elk and mule deer are often managed as one, or management objectives are expressed solely in terms of elk. Because of this, the two species are considered together in this cumulative impact analysis. A method was developed to estimate potential cumulative impacts of multiple hydroelectric development on known and potential use areas. Five habitat components were assessed: permanent habitat loss, loss of forest cover (where limiting), loss of special areas, migration blockage, and road or travel disturbance. Impact levels from 0 (none) to 4 (high) were assigned for each development and for each habitat component based on the impacts anticipated and the estimated value of the site to elk and mule deer. Resource agencies past and future plans, aerial photography, maps, and site visits were used. Impacts were considered additive for all but the migration blockage component, which was adjusted for potential synergism between developments. The method helped distinguish potentially harmful from relatively benign development scenarios. C1 ARGONNE NATL LAB,DIV ENERGY & ENVIRONM SYST,PORTLAND,OR 97219. NR 37 TC 1 Z9 1 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1591 J9 APPL ANIM BEHAV SCI JI Appl. Anim. Behav. Sci. PD FEB PY 1991 VL 29 IS 1-4 BP 225 EP 238 DI 10.1016/0168-1591(91)90250-2 PG 14 WC Agriculture, Dairy & Animal Science; Behavioral Sciences; Veterinary Sciences SC Agriculture; Behavioral Sciences; Veterinary Sciences GA FE755 UT WOS:A1991FE75500017 ER PT J AU SHIANG, M LINDEN, JC MOHAGHEGHI, A GROHMANN, K HIMMEL, ME AF SHIANG, M LINDEN, JC MOHAGHEGHI, A GROHMANN, K HIMMEL, ME TI ENHANCED PRODUCTION OF CELLULASE USING ACIDOTHERMUS-CELLULOLYTICUS IN FED-BATCH CULTURE SO APPLIED MICROBIOLOGY AND BIOTECHNOLOGY LA English DT Article ID THERMOSTABLE CELLULASES AB Fed-batch fermentations of Acidothermus cellulolyticus utilizing mixtures of cellulose and sugars were investigated for potential improvements in cellulase enzyme production. In these fermentations, we combined cellulose from several sources with various simple sugars at selected concentrations. The best source of cellulose for cellulase production was found to be ball-milled Solka Floc at 15 g/l. Fed-batch fermentations with cellobiose and Solka Floc increased cell mass only slightly, but succeeded in significantly enhancing cellulase synthesis compared to batch conditions. Maximum cellulase activities obtained from fermentations initiated with 2.5 g cellobiose/l and 15 g Solka Floc/l were 0.187 units (U)/ml, achieved by continuous feeding to maintain < 0.1 g cellobiose/l, and 0.215 U/ml using the same initial medium when 2.5 g cellobiose/l was step-fed after the sugar was nearly consumed. In batch, dual-substrate systems consisting of simple sugars with Solka Floc, substrate inhibition was evident in terms of specific growth rates, specific productivity values, and maximum enzyme yields. Limiting concentrations of glucose or sucrose at 5 g/l, and cellobiose at 2.5 g/l, in the presence of Solka Floc, yielded cellulase activities of 0.134, 0.159, and 0.164 U/ml, respectively. C1 SOLAR ENERGY RES INST,DIV SOLAR FUELS RES,BIOTECHNOL RES BRANCH,APPL BIOL SCI STN,GOLDEN,CO 80401. COLORADO STATE UNIV,DEPT MICROBIOL,FT COLLINS,CO 80523. COLORADO STATE UNIV,DEPT AGR & CHEM ENGN,FT COLLINS,CO 80523. NR 14 TC 3 Z9 3 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0175-7598 J9 APPL MICROBIOL BIOT JI Appl. Microbiol. Biotechnol. PD FEB PY 1991 VL 34 IS 5 BP 591 EP 597 PG 7 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA EZ518 UT WOS:A1991EZ51800008 ER PT J AU KARR, TJ AF KARR, TJ TI TEMPORAL RESPONSE OF ATMOSPHERIC-TURBULENCE COMPENSATION SO APPLIED OPTICS LA English DT Note DE ATMOSPHERIC PROPAGATION; ADAPTIVE OPTICS ID SPATIAL LIGHT-MODULATOR; ADAPTIVE OPTICS; SYSTEMS; POWER AB The temporal kernel for the phase error variance due to atmospheric turbulence is calculated. This kernel, convolved with the servo transfer function, determines the temporal error of any turbulence compensation scheme. RP KARR, TJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 15 TC 4 Z9 4 U1 1 U2 3 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 1 PY 1991 VL 30 IS 4 BP 363 EP 364 PG 2 WC Optics SC Optics GA EW644 UT WOS:A1991EW64400001 PM 20581991 ER PT J AU KEARNS, EV HUGLY, S SOMERVILLE, CR AF KEARNS, EV HUGLY, S SOMERVILLE, CR TI THE ROLE OF CYTOCHROME-B5 IN DELTA-12 DESATURATION OF OLEIC-ACID BY MICROSOMES OF SAFFLOWER (CARTHAMUS-TINCTORIUS L) SO ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS LA English DT Note ID RAT-LIVER; OLEOYL-PHOSPHATIDYLCHOLINE; PURIFICATION; REDUCTASE; PROTEIN; ACYLTRANSFERASE; BIOSYNTHESIS; COTYLEDONS; SEEDS; NADH C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. MICHIGAN STATE UNIV,GENET PROGRAM,E LANSING,MI 48824. RI Somerville, Christopher/A-4048-2009 OI Somerville, Christopher/0000-0003-4647-0094 NR 28 TC 49 Z9 49 U1 0 U2 2 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0003-9861 J9 ARCH BIOCHEM BIOPHYS JI Arch. Biochem. Biophys. PD FEB 1 PY 1991 VL 284 IS 2 BP 431 EP 436 DI 10.1016/0003-9861(91)90319-E PG 6 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA ET071 UT WOS:A1991ET07100031 PM 1989527 ER PT J AU PREMUZIC, ET LIN, M ZHU, HL GREMME, AM AF PREMUZIC, ET LIN, M ZHU, HL GREMME, AM TI SELECTIVITY IN METAL UPTAKE BY STATIONARY PHASE MICROBIAL-POPULATIONS SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID RHIZOPUS-ARRHIZUS; PSEUDOMONAS-AERUGINOSA; PENICILLIUM BIOMASS; THORIUM BIOSORPTION; BIOLOGICAL-SYSTEMS; BACILLUS-SUBTILIS; ESCHERICHIA-COLI; OUTER-MEMBRANE; CELL-WALLS; URANIUM VI AB In the interaction of metals with the cellular biomass of microorganisms in aqueous solutions, cell wall constituents have been implicated as being responsible for metal binding. Chemical and structural characteristics of cell membranes vary with species and should therefore influence the selective capacity for uptake of different metals by different microorganisms, and thus also influence the behavior of metallic species in the environment. While the rates of uptake of metals by microorganisms have been studied extensively, the comparative capacity for selective uptake of metals by different species of microorganisms under identical experimental conditions has not been studied systematically. To test for this property, cellular biomass derived from eight representative microorganisms has been allowed to interact under similar experimental conditions with acidic solutions of seven heavy metals. The results of these studies show that, in addition to metal selectivity, there is also a species dependent differentiation in the uptake capacity. C1 SHANGHAI ENVIRONM PROTECT RES INST,SHANGHAI,PEOPLES R CHINA. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RP PREMUZIC, ET (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 65 TC 22 Z9 23 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD FEB PY 1991 VL 20 IS 2 BP 234 EP 240 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA EW170 UT WOS:A1991EW17000011 ER PT J AU LIANG, EP AF LIANG, EP TI STRUCTURE OF THERMAL PAIR CLOUDS AROUND GAMMA-RAY-EMITTING BLACK-HOLES SO ASTROPHYSICAL JOURNAL LA English DT Article DE ACCRETION; BLACK HOLES; GALAXIES, NUCLEI; GAMMA-RAYS, BURSTS; RADIATION MECHANISMS; X-RAYS, BINARIES ID CYGNUS X-1; ACCRETION DISKS; GALACTIC NUCLEI; BINARY-SYSTEMS; SPECTRUM; VARIABILITY; INSTABILITY; PLASMAS AB Using certain simplifying assumptions, we derive from first principles the general structure of a quasi-spherical thermal pair-balanced cloud surrounding an accreting black hole. We find that pair-dominated hot solutions exist only for a restricted range of the viscosity parameter. These results are then applied as examples to the 1979 HEAO 3 gamma-ray data of Cygnus X-1 and the Galactic center. We obtain values for the viscosity parameter alpha-BAR lying in the range approximately 0.1-0.01. Since the lack of synchrotron soft photons requires the magnetic field to be typically less than 1% of the equipartition value, we conclude that magnetic field cannot be the main contributor to the viscous stress of the inner accretion flow, at least during the high gamma-ray states. C1 STANFORD UNIV, STANFORD, CA 94305 USA. RP LIANG, EP (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, L-297, LIVERMORE, CA 94550 USA. NR 34 TC 15 Z9 15 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 1 PY 1991 VL 367 IS 2 BP 470 EP 475 DI 10.1086/169643 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET683 UT WOS:A1991ET68300008 ER PT J AU BURNARD, DJ ARONS, J KLEIN, RI AF BURNARD, DJ ARONS, J KLEIN, RI TI ACCRETION POWERED PULSARS - CONTINUUM SPECTRA AND LIGHT CURVES OF SETTLING ACCRETION MOUNDS SO ASTROPHYSICAL JOURNAL LA English DT Article DE PULSARS; RADIATIVE TRANSFER; STARS, ACCRETION; STARS, NEUTRON; X-RAYS, BINARIES ID X-RAY PULSARS; MAGNETIZED NEUTRON STARS; RADIATIVE-TRANSFER; LUMINOSITY DEPENDENCE; COMPTONIZATION; EXO-2030+375; DISCOVERY; PLASMA; MODELS; X-1 AB We apply the radiative transfer technique described in Burnard, Klein, and Arons to model the polarimetric spectra expected from a monud of accreting plasma settling subsonically onto the polar cap regions of an X-ray pulsar. We employ an analytical model of the accretion flow near the polar caps of the neutron stars, described briefly here, and demonstrate how the emission from such an accretion mound can be computed from a series of one-dimensional slabs of nonuniform material. We compare the results of our detailed calculations for these slabs with those obtained from a simple mode-coupled modified blackbody model. We find that the geometry of the elevated mound forces the observer to receive photons from patches whose surfaces subtend a wide range of angles to the line of sight. The resulting averaging of intensity over the surface of the mound greatly reduces the variation in intensity and polarization found in single-slab models. We conclude that single-slab models are inadequate for representing the emission region of all but the lowest luminosity X-ray pulsars; a self-consistent model of both the accretion flow and the radiation field is required. For the simple mound studied here, in which the mass flux far above the stellar surface is independent of distance from the magnetic axis, the emission from the postshock settling zone does not contain enough low-frequency photons to model the observed spectra of X-ray pulsars, specifically Her X-1. We point out that mound models with steeper gradients and/or additional soft-photon sources are required to explain the large number of low-frequency photons seen in X-ray pulsars. A discussion of the importance of the radiation-dominated shock and its outer sheath (which are neglected in this paper), lead us to suggest that past success achieved using thin uniform backlit slabs can be interpreted dynamically as the Comptonizing layer formed by the shock itself, backlit by the saturated spectrum radiated from mounds of the type described here. C1 UNIV CALIF BERKELEY,DEPT ASTRON,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,LAWRENCE LIVERMORE NATL LAB,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. RP BURNARD, DJ (reprint author), APPLE COMP INC,20525 MARIANI AVE,MAIL STOP 22-AE,CUPERTINO,CA 95014, USA. NR 32 TC 51 Z9 50 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 1991 VL 367 IS 2 BP 575 EP 592 DI 10.1086/169653 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET683 UT WOS:A1991ET68300018 ER PT J AU TURNER, MS WATKINS, R WIDROW, LM AF TURNER, MS WATKINS, R WIDROW, LM TI MICROWAVE DISTORTIONS FROM COLLAPSING DOMAIN-WALL BUBBLES SO ASTROPHYSICAL JOURNAL LA English DT Article DE COSMIC BACKGROUND RADIATION; COSMOLOGY; EARLY UNIVERSE ID RADIATION; UNIVERSE AB It has been suggested that large-scale structure can be seeded by a postrecombination phase transition that produces soft domain walls. We find that oscillating domain-wall bubbles produce a distinctive signature on the microwave sky: hot and cold spots with amplitude characterized by G-sigma-H0(-1) (sigma is the surface tension of the wall). These fluctuations are non-Gaussian and offer a powerful probe of such models. C1 HARVARD SMITHSONIAN CTR ASTROPHYS,CAMBRIDGE,MA 02138. UNIV TORONTO,CANADIAN INST THEORET ASTROPHYS,TORONTO M5S 1A1,ONTARIO,CANADA. UNIV CHICAGO,ENRICO FERMI INST,DEPT ASTRON & ASTROPHYS,CHICAGO,IL 60637. HARVARD UNIV,DEPT PHYS,CAMBRIDGE,MA 02138. RP TURNER, MS (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NAT ACCELERATOR LAB,MS 209,POB 500,BATAVIA,IL 60510, USA. NR 24 TC 25 Z9 25 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 1991 VL 367 IS 2 BP L43 EP L47 DI 10.1086/185928 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ET684 UT WOS:A1991ET68400002 ER PT J AU VANRIPER, KA AF VANRIPER, KA TI NEUTRON-STAR THERMAL EVOLUTION SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE DENSE MATTER; STARS, EVOLUTION; STARS, INTERIORS; STARS, NEUTRON; STARS, X-RAYS ID LIQUID-METAL PHASE; X-RAY OBSERVATIONS; TEMPERATURE QUANTUM CORRECTIONS; CRYSTALLINE LATTICE PHASE; PAIR BREMSSTRAHLUNG; DENSE MATTER; CONDUCTIVITIES; MODELS; HOT AB We present a model for calculating the evolution of neutron stars in the thermal evolution approximation, which follows the detailed temperature dependence in the interior of the star assuming a fixed density structure. A new numerical algorithm for solving the thermal evolution equations is presented and comparisons are made with other algorithms. Other numerical details of the model are discussed. The neutrino emissivities, heat capacities, thermal conductivities, and superfluid treatment used in the models are described. A comparison is made to the full-evolution models of Nomoto and Tsuruta. Results of the thermal evolution model are presented for representative neutron star models of a gravitational mass M = 1.4 M. with and without strong surface magnetic fields, and also for stars with a central accelerated cooling mechanism. Isothermal cooling models are examined to determine the ages beyond which the cooling model applies. Our predicted luminosities are compared with soft X-ray observations made with the Einstein Observatory. RP VANRIPER, KA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV APPL THEORET PHYS,RADIAT TRANSPORT GRP,POB 1663,X-6,MS B226,LOS ALAMOS,NM 87545, USA. NR 53 TC 98 Z9 98 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 S WOODLAWN AVE, CHICAGO, IL 60637 SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 1991 VL 75 IS 2 BP 449 EP 462 DI 10.1086/191538 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EU740 UT WOS:A1991EU74000009 ER PT J AU TENFORDE, TS AF TENFORDE, TS TI BIOLOGICAL INTERACTIONS OF EXTREMELY-LOW-FREQUENCY ELECTRIC AND MAGNETIC-FIELDS SO BIOELECTROCHEMISTRY AND BIOENERGETICS LA English DT Review ID BRAIN-TISSUE INVITRO; ELECTROMAGNETIC-FIELDS; CYCLOTRON-RESONANCE; ORNITHINE DECARBOXYLASE; CELLULAR TRANSCRIPTION; MEMBRANE IONS; CALCIUM-IONS; CELLS; EXPOSURE; ENERGY AB A description is given of the fundamental physical properties of extremely-low-frequency (ELF) electromagnetic fields, and the mechanisms through which these fields interact with the human body at a macroscopic level. Evidence is presented that cell membranes play an important role in transducing ELF signals. Both experimental evidence and theoretical models are described that relate pericellular currents and electrochemical events at the outer membrane surface to transmembrane signaling pathways and cytoplasmic responses. Biological responses to ELF fields at the tissue, cellular and molecular levels are summarized, including new evidence that ELF field exposure produces alterations in messenger RNA synthesis, gene expression and the cytoplasmic concentrations of specific proteins. RP TENFORDE, TS (reprint author), PACIFIC NW LAB, CTR LIFE SCI, K1-50, RICHLAND, WA 99352 USA. NR 51 TC 63 Z9 63 U1 0 U2 10 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0302-4598 J9 BIOELECTROCH BIOENER JI Bioelectrochem. Bioenerg. PD FEB PY 1991 VL 25 IS 1 BP 1 EP 17 DI 10.1016/0302-4598(91)87015-9 PG 17 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA FA310 UT WOS:A1991FA31000001 ER PT J AU MOONEY, HA DRAKE, BG LUXMOORE, RJ OECHEL, WC PITELKA, LF AF MOONEY, HA DRAKE, BG LUXMOORE, RJ OECHEL, WC PITELKA, LF TI PREDICTING ECOSYSTEM RESPONSES TO ELEVATED CO2 CONCENTRATIONS SO BIOSCIENCE LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; LONG-TERM EXPOSURE; GROWTH-RESPONSES; CLIMATE CHANGE; PHOTOSYNTHETIC INHIBITION; PHOSPHORUS DEFICIENCY; ESTUARINE MARSH; NUTRIENT-UPTAKE; PINUS-RADIATA; WATER-STRESS C1 SMITHSONIAN ENVIRONM RES CTR,EDGEWATER,MD 21037. OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831. SAN DIEGO STATE UNIV,SYST ECOL RES GRP,SAN DIEGO,CA 92182. ELECT POWER RES INST,PALO ALTO,CA 94303. RP MOONEY, HA (reprint author), STANFORD UNIV,DEPT BIOL SCI,STANFORD,CA 94305, USA. RI Oechel, Walter/F-9361-2010 OI Oechel, Walter/0000-0002-3504-026X NR 82 TC 239 Z9 246 U1 5 U2 35 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD FEB PY 1991 VL 41 IS 2 BP 96 EP 104 DI 10.2307/1311562 PG 9 WC Biology SC Life Sciences & Biomedicine - Other Topics GA EU719 UT WOS:A1991EU71900010 ER PT J AU CHANG, S REID, ME CONBOY, J KAN, YW MOHANDAS, N AF CHANG, S REID, ME CONBOY, J KAN, YW MOHANDAS, N TI MOLECULAR CHARACTERIZATION OF ERYTHROCYTE GLYCOPHORIN-C VARIANTS SO BLOOD LA English DT Article ID MEMBRANE SIALOGLYCOPROTEIN-BETA; BLOOD-GROUP ANTIGENS; GENETIC-VARIANTS; LACKING; GAMMA; CDNA; ASSOCIATION; PROTEIN; ALPHA; DELTA C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,1 CYCLOTRON RD,BLDG 74-157,BERKELEY,CA 94720. SOUTHWESTERN REG BLOOD TRANSFUS CTR,BRISTOL,ENGLAND. UNIV CALIF SAN FRANCISCO,DEPT LAB MED,SAN FRANCISCO,CA 94143. UNIV CALIF SAN FRANCISCO,HOWARD HUGHES MED INST,SAN FRANCISCO,CA 94143. FU NIDDK NIH HHS [DK 32094] NR 26 TC 24 Z9 26 U1 0 U2 0 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 1991 VL 77 IS 3 BP 644 EP 648 PG 5 WC Hematology SC Hematology GA EV332 UT WOS:A1991EV33200029 PM 1991173 ER PT J AU YELIN, TS PATTON, HJ AF YELIN, TS PATTON, HJ TI SEISMOTECTONICS OF THE PORTLAND, OREGON, REGION SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article ID SURFACE-WAVES; EARTHQUAKE; WASHINGTON; RANGE; ZONE; ATTENUATION; SCALE; BASIN AB Portland, Oregon, lies in the southern half of an approximately rectangular basin measuring 30 by 50 km. Since 1969, there have been no earthquakes with M greater-than-or-equal-to 4.0 in or on the margins of the Portland basin, but this level of seismicity may not be characteristic of the region. Using microseismicity data collected by the University of Washington regional short-period seismograph network for the period mid-1982 through 1989, we have determined P-wave focal mechanisms for four individual earthquakes and three groups of earthquakes. We have also relocated the 6 November 1962, M(w) = 5.2 Portland earthquake and analyzed regional surface-wave recordings of this event, using the seismic moment-tensor inversion technique. The results of these seismic analyses, along with geologic and other geophysical data, are integrated into a seismotectonic model of the Portland basin. The P-wave mechanisms are compatible with dextral strike-slip motion along approximately NW-striking fault zones bounding the eastern and western margins of the basin. We speculate that there is a dextral strike-slip fault zone, which we call the Frontal Fault Zone, along the eastern margin of the Portland basin. The western margin has been previously recognized as a zone of dextral strike-slip faulting, known as the Portland Hills Fault Zone. The epicenter of the 1962 earthquake is located between the two fault zones and lies approximately 15 km NE of downtown Portland. Our preferred mechanism is normal faulting on NE- or NNE-trending fault planes. These results support the hypothesis posed by previous investigators that the Portland basin is a pull-apart basin and are evidence for contemporary crustal extension between the Frontal and Portland Hills fault zones. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB, LIVERMORE, CA 94550 USA. RP UNIV WASHINGTON, US GEOL SURVEY, GEOPHYS PROGRAM AK-50, SEATTLE, WA 98195 USA. NR 43 TC 13 Z9 13 U1 0 U2 1 PU SEISMOLOGICAL SOC AMER PI ALBANY PA 400 EVELYN AVE, SUITE 201, ALBANY, CA 94706-1375 USA SN 0037-1106 EI 1943-3573 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD FEB PY 1991 VL 81 IS 1 BP 109 EP 130 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA EY811 UT WOS:A1991EY81100006 ER PT J AU GROSSNICKLE, SC ARNOTT, JT MAJOR, JE TSCHAPLINSKI, TJ AF GROSSNICKLE, SC ARNOTT, JT MAJOR, JE TSCHAPLINSKI, TJ TI INFLUENCE OF DORMANCY INDUCTION TREATMENTS ON WESTERN HEMLOCK SEEDLINGS .1. SEEDLING DEVELOPMENT AND STOCK QUALITY ASSESSMENT SO CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE LA English DT Article ID ROOT-GROWTH CAPACITY; WATER RELATIONS; WHITE SPRUCE; SOIL-TEMPERATURE; SHOOT GROWTH; JACK PINE; STRESS; PHOTOPERIOD; MORPHOLOGY; PATTERNS AB Western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedling were grown in a greenhouse and subjected to four dormancy induction treatments (DIT) (i.e., long-day dry, long-day wet, short-day dry, and short-day wet) during mid-summer. In the late summer and fall, seedling development was monitored and it was found that (1) short-day DIT caused a rapid cessation of shoot growth; (2) short-day DIT caused rapid fall development of needle primordia, while long-day DIT took until midwinter to produce the same number of needle primordia; and (3) short-day DIT seedling had lower saturated and turgor loss point osmotic potentials and greater maximum modulus of elasticity in October than long-day DIT. Seedlings were tested with a comprehensive stock quality assessment procedure just before late winter field planting. These tests showed the following: (1) morphological parameters: short-day DIT reduced shoot to root ratios; (2) pressure-volume analysis: short-day wet seedling had the lowest osmotic potential at saturation and turgor loss point; (3) soluble sugar analysis: greater levels of total soluble sugars were found in non water stressed DIT compared with water stressed DIT seedlings; (4) seedling water movement: short-day DIT seedlings had the lowest resistance to water movement at low root temperature (5-degrees-C); (5) low root temperature response: short-day compared with long-day DIT seedling had greater photosynthesis and stomatal conductance at low root temperatures; (6) root growth capacity: seedling from all DIT were capable of growing roots at optimum root temperature (22-degrees-C), but short-day compared with long-day DIT had greater root growth at low root temperatures; (7) drought stress response: short-day wet seedling had the highest photosynthesis and stomatal conductance levels as predawn shoot water potentials decreased; and (8) frost hardiness: short-day wet seedling had the least needle damage when tested at temperatures of -15 and -18-degrees-C. C1 FORESTRY CANADA,PACIFIC FORESTRY CTR,VICTORIA V8Z 1M5,BC,CANADA. OAK RIDGE NATL LAB,DIV HYG,OAK RIDGE,TN 37831. RP GROSSNICKLE, SC (reprint author), BRITISH COLUMBIA RES CORP,CTR FOREST BIOTECHNOL,3650 WESBROOK MALL,VANCOUVER V6S 2L2,BC,CANADA. NR 58 TC 31 Z9 32 U1 1 U2 2 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA ON K1A 0R6, CANADA SN 0045-5067 J9 CAN J FOREST RES JI Can. J. For. Res.-Rev. Can. Rech. For. PD FEB PY 1991 VL 21 IS 2 BP 164 EP 174 DI 10.1139/x91-020 PG 11 WC Forestry SC Forestry GA EX335 UT WOS:A1991EX33500003 ER PT J AU VANDERLAAN, M ALEXANDER, J THOMAS, C DJANEGARA, T HWANG, M WATKINS, BE WALLIN, H AF VANDERLAAN, M ALEXANDER, J THOMAS, C DJANEGARA, T HWANG, M WATKINS, BE WALLIN, H TI IMMUNOCHEMICAL DETECTION OF RODENT HEPATIC AND URINARY METABOLITES OF COOKING-INDUCED FOOD MUTAGENS SO CARCINOGENESIS LA English DT Article ID MONOCLONAL-ANTIBODIES; BEEF; 2-AMINO-3,8-DIMETHYLIMIDAZO<4,5-F>QUINOXALINE; RATS; PHIP AB Monoclonal antibodies, previously selected to bind either 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were evaluated to determine their binding properties with several known metabolites of these compounds purified from rat hepatocyte cultures. Both 2-N- and 5-substituted MeIQx metabolites were recognized by antibodies AIA-2 and AIA-11, while antibodies AIA-1 and AIA-12 bound N-substituted metabolites only. Anti-PhIP antibodies bound N-hydroxy-PhIP, N-sulfinamide-glutathione-PhIP and N-hydroxy-glucuronide-PhIP. Immunoaffinity columns incorporating these antibodies were used to concentrate and purify both the unmetabolized parent compounds and several relatively non-polar metabolities from the urine of rats exposed either to MeIQx or PhIP. Several of these metabolites corresponded with available standards of previously identified polar conjugate metabolites, e.g. N-sulfamate-MeIQx and N(OH)-gluc-PhIP, while others are as yet unidentified. Immunoaffinity chromatography is demonstrated as a promising means of selectively concentrating metabolites of PhIP and MeIQx from urine. C1 NATL INST PUBL HLTH,DEPT ENVIRONM MED,N-4062 OSLO,NORWAY. RP VANDERLAAN, M (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550, USA. RI Wallin, Hakan/I-6459-2012 OI Wallin, Hakan/0000-0001-7716-0166 FU NCI NIH HHS [R01 CA40811-03, U01 CA48446-01] NR 19 TC 12 Z9 12 U1 0 U2 1 PU OXFORD UNIV PRESS UNITED KINGDOM PI OXFORD PA WALTON ST JOURNALS DEPT, OXFORD, ENGLAND OX2 6DP SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD FEB PY 1991 VL 12 IS 2 BP 349 EP 354 DI 10.1093/carcin/12.2.349 PG 6 WC Oncology SC Oncology GA EW904 UT WOS:A1991EW90400030 PM 1995196 ER PT J AU DERSCH, MA BEMENT, WM LARABELL, CA MECCA, MD CAPCO, DG AF DERSCH, MA BEMENT, WM LARABELL, CA MECCA, MD CAPCO, DG TI CORTICAL MEMBRANE-TRAFFICKING DURING THE MEIOTIC RESUMPTION OF XENOPUS-LAEVIS OOCYTES SO CELL AND TISSUE RESEARCH LA English DT Article DE MEIOSIS; ENDOPLASMIC RETICULUM, SPECIALIZED; CORTICAL GRANULES, OVUM; XENOPUS-LAEVIS (ANURA) ID ISOLATED AMPHIBIAN OOCYTES; MESSENGER-RNA; INTERMEDIATE FILAMENTS; PROTEIN INCORPORATION; EGGS; MATURATION; CALCIUM; FERTILIZATION; FROG; REORGANIZATION AB Changes in the organization of membranous structures in the amphibian oocyte cortex were studied during the process of progesterone-induced meiotic resumption. Progesterone treatment of Xenopus laevis oocytes induced short term and longer term changes in the cortical membranes. In the short term, progesterone induced a burst of endocytosis mediated through coated pits and coated vesicles. Immuno-electron-microscopic localization of progesterone suggested that the progesterone receptor, bound to its ligand, is endocytosed during progesterone-induced endocytosis. Also demonstrated was the existence of a cisternal membrane network, referred to as the primordial cortical endoplasmic reticulum, which surrounds portions of the cortical granules in oocytes. The primordial cortical endoplasmic reticulum is more highly developed in the animal hemisphere than the vegetal hemisphere. Over the long term, during the meiotic resumption, more membrane is recruited into this network to form the cortical endoplasmic reticulum observed by others in the metaphase II egg. This evidence demonstrates that the cortex serves as a site for dynamic changes in membrane organization and that the most extensive changes occur in the animal hemisphere. These data support previous observations that the animal hemisphere is better structured for sperm penetration than is the vegetal hemisphere. C1 ARIZONA STATE UNIV,DEPT ZOOL,TEMPE,AZ 85287. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,INTERMEDIATE VOLTAGE ELECTR MICROSCOPE FACIL,BERKELEY,CA 94720. FU NICHD NIH HHS [HD00598, HD23686] NR 34 TC 12 Z9 12 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0302-766X J9 CELL TISSUE RES JI Cell Tissue Res. PD FEB PY 1991 VL 263 IS 2 BP 375 EP 383 DI 10.1007/BF00318779 PG 9 WC Cell Biology SC Cell Biology GA EV790 UT WOS:A1991EV79000019 PM 2007258 ER PT J AU NEUHAUSER, D JUDSON, RS JAFFE, RL BAER, M KOURI, DJ AF NEUHAUSER, D JUDSON, RS JAFFE, RL BAER, M KOURI, DJ TI TOTAL INTEGRAL REACTIVE CROSS-SECTIONS FOR F+H-2-]HF+H - COMPARISON OF CONVERGED QUANTUM, QUASI-CLASSICAL TRAJECTORY AND EXPERIMENTAL RESULTS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POTENTIAL-ENERGY SURFACE; WAVE-PACKET APPROACH; DEPENDENT SCHRODINGER-EQUATION; TRANSITION-STATE-THEORY; SCATTERING CALCULATIONS; F+H2 REACTION; MOLECULAR-BEAM; F+H2->HF+H; DYNAMICS; PROBABILITIES AB We report converged quantum total integral reactive cross sections for the reaction F + H-2 --> HF + H, for initial rotational states j(i) = 0 and 1, using a time-dependent method. Our results are compared to classical results and to the experimental results of Neumark et al. Strong quantum effects are found in the threshold region for both initial states; i.e. in the dependence of the reaction on initial state for low energies. The classical results agree better with experiment than to the quantum results; this appears to be due to errors in the potential used. C1 SANDIA NATL LABS, CTR COMP ENGN, LIVERMORE, CA 94550 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. SOREQ NUCL RES CTR, DEPT THEORET PHYS & APPL MATH, IL-70600 YAVNE, ISRAEL. UNIV HOUSTON, DEPT PHYS, HOUSTON, TX 77204 USA. UNIV HOUSTON, DEPT CHEM, HOUSTON, TX 77204 USA. RP PRINCETON UNIV, DEPT CHEM, PRINCETON, NJ 08544 USA. OI Judson, Richard/0000-0002-2348-9633 NR 42 TC 78 Z9 78 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 EI 1873-4448 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 1 PY 1991 VL 176 IS 6 BP 546 EP 550 DI 10.1016/0009-2614(91)90253-6 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EX468 UT WOS:A1991EX46800010 ER PT J AU SCHENTER, GK DUKE, CB AF SCHENTER, GK DUKE, CB TI THEORY OF PHOTOINDUCED TWISTING DYNAMICS IN POLAR-SOLVENTS - APPLICATION TO DIMETHYLAMINOBENZONITRILE IN PROPANOL AT LOW-TEMPERATURES SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BARRIERLESS ELECTRONIC RELAXATION; INTRAMOLECULAR CHARGE-TRANSFER; ACTIVATION BARRIER; FLUORESCENCE; SOLVATION; ABSENCE; TICT AB A new microscopic theoretical model of the twisted intramolecular charge transfer mechanism responsible for the dual fluorescence of dimethylaminobenzonitrile (DMABN) in polar solvents is developed. It is applied to give a quantitative description of experimental measurements describing the dynamics of this process for DMABN in propanol at T = 223 K. RP SCHENTER, GK (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. RI Schenter, Gregory/I-7655-2014 OI Schenter, Gregory/0000-0001-5444-5484 NR 29 TC 28 Z9 28 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD FEB 1 PY 1991 VL 176 IS 6 BP 563 EP 570 DI 10.1016/0009-2614(91)90256-9 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EX468 UT WOS:A1991EX46800013 ER PT J AU CAREY, WP WANGEN, LE AF CAREY, WP WANGEN, LE TI DETERMINING CHEMICAL CHARACTERISTICS OF PLUTONIUM SOLUTIONS USING VISIBLE SPECTROMETRY AND MULTIVARIATE CHEMOMETRIC METHODS SO CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS LA English DT Article ID SQUARES AB Two chemometric analysis approaches for rapidly screening samples are presented. The first method is for determining Pu(III) and nitric acid concentrations by using the multivariate calibration technique of partial least squares (PLS) regression. Quantitation of plutonium using its visible spectrum is straightforward; however, the effects of nitric acid on the Pu(III) absorption spectra are subtle, and nitric acid quantitation from the absorbance spectrum is more difficult. In this study PLS regression is successfully applied to quantitate both plutonium and nitric acid by using the information contained in the absorption spectra of appropriate solutions. Evaluation of the calibration models, using test samples that span the range of the calibration concentrations, gave predictions consistent with the standard error of the calibration models. Secondly, pattern recognition methods are used to investigate the effects of various amounts of nitric acid, fluoride, or oxalate on visible spectra of Pu(IV) solutions. The methods enable qualitative estimates of the solution composition, which can potentially be used to adjust solution properties to desired specifications. The main pattern recognition methods employed are nearest neighbor classification and principal components analysis. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV CHEM & LASER SCI,G740,LOS ALAMOS,NM 87545. NR 21 TC 13 Z9 13 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-7439 J9 CHEMOMETR INTELL LAB JI Chemometrics Intell. Lab. Syst. PD FEB PY 1991 VL 10 IS 1-2 BP 245 EP 257 DI 10.1016/0169-7439(91)80055-U PG 13 WC Automation & Control Systems; Chemistry, Analytical; Computer Science, Artificial Intelligence; Instruments & Instrumentation; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Automation & Control Systems; Chemistry; Computer Science; Instruments & Instrumentation; Mathematics GA FC580 UT WOS:A1991FC58000029 ER PT J AU CLARK, DS FERNANDEZ, EJ AF CLARK, DS FERNANDEZ, EJ TI NONINVASIVE STUDIES OF BIOREACTORS SO CHEMTECH LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; ESCHERICHIA-COLI; SPECTROSCOPY; INVIVO; METABOLISM C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. RP CLARK, DS (reprint author), UNIV CALIF BERKELEY,CHEM ENGN,B-84 HILDEBRAND HALL,BERKELEY,CA 94701, USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0009-2703 J9 CHEMTECH JI Chemtech PD FEB PY 1991 VL 21 IS 2 BP 99 EP 105 PG 7 WC Chemistry, Applied SC Chemistry GA EY186 UT WOS:A1991EY18600010 ER PT J AU SUPERKO, HR AF SUPERKO, HR TI PREVENTION AND REGRESSION OF ATHEROSCLEROSIS WITH DRUG-THERAPY SO CLINICAL CARDIOLOGY LA English DT Article ID CORONARY-ARTERY DISEASE; LOW-DENSITY LIPOPROTEIN; HEART-DISEASE; RISK-FACTORS; MYOCARDIAL-INFARCTION; NICOTINIC-ACID; BYPASS-SURGERY; PROGRESSION; CHOLESTEROL; INTERVENTION C1 STANFORD UNIV,LIPID RES CLIN,STANFORD,CA 94305. STANFORD UNIV,MED CTR,SCH MED,STANFORD,CA 94305. ALTA BATES HERRICK HOSP,CTR PROGRESS ATHEROSCLEROSIS MANAGEMENT,BERKELEY,CA. RP SUPERKO, HR (reprint author), UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,CHOLESTEROL RES CTR,3030 TELE AVE,BERKELEY,CA 94705, USA. OI Superko, H. Robert/0000-0002-3542-0393 NR 49 TC 0 Z9 0 U1 0 U2 0 PU CLINICAL CARDIOLOGY PUBL CO PI MAHWAH PA PO BOX 832, MAHWAH, NJ 07430-0832 SN 0160-9289 J9 CLIN CARDIOL JI Clin. Cardiol. PD FEB PY 1991 VL 14 IS 2 SU 1 BP 40 EP 47 PG 8 WC Cardiac & Cardiovascular Systems SC Cardiovascular System & Cardiology GA EV704 UT WOS:A1991EV70400006 ER PT J AU DEC, JE KELLER, JO HONGO, I AF DEC, JE KELLER, JO HONGO, I TI TIME-RESOLVED VELOCITIES AND TURBULENCE IN THE OSCILLATING FLOW OF A PULSE COMBUSTOR TAIL-PIPE SO COMBUSTION AND FLAME LA English DT Article AB The cyclic behavior of the oscillating velocity field in the tail pipe of a pulse combustor was studied using laser doppler velocimetry. In this flow, the oscillations result from an acoustic resonance and have amplitudes of up to 5 times the mean velocity. Oscillation frequencies were varied from 67 to 101 Hz. Streamwise velocity and turbulence-intensity boundary layer profiles were measured to within 130-mu-m of the wall, and transverse turbulence measurements were made to within 2 mm. The phase relationships of the velocity, turbulence intensity, and combustion chamber pressure oscillations are compared. Velocity oscillations near the wall are found to phase lead those in the center of the pipe, creating periodic flow reversals through the boundary layer. A comparison is made between this turbulent oscillating boundary layer and the laminar oscillating boundary layer for flow over a flat plate. The effects of axial position, pulsation frequency, pulsation amplitude, and mean flow rate on the velocity and turbulence profiles are discussed. Time-resolved wall shear stresses (directly calculated from the velocity measurements) are presented and compared with those of steady turbulent flow. Time-averaged velocity and turbulence profiles are also compared with those of conventional steady turbulent flows. The time-averaged velocity profile is found to be flatter than that of steady flow at the same mean Reynolds number, and both the streamwise and transverse turbulence intensities are found to be significantly higher than those of steady flow. C1 UNIV MICHIGAN,ANN ARBOR,MI 48109. TOSHIBA CO LTD,YOKOHAMA,JAPAN. RP DEC, JE (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94550, USA. NR 31 TC 35 Z9 37 U1 1 U2 4 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 1991 VL 83 IS 3-4 BP 271 EP 292 DI 10.1016/0010-2180(91)90075-M PG 22 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA FE583 UT WOS:A1991FE58300008 ER PT J AU STAMPS, DW TIESZEN, SR AF STAMPS, DW TIESZEN, SR TI THE INFLUENCE OF INITIAL PRESSURE AND TEMPERATURE ON HYDROGEN-AIR-DILUENT DETONATIONS SO COMBUSTION AND FLAME LA English DT Article ID GASEOUS DETONATIONS; MIXTURES; OXIDATION; KINETICS AB We have studied the influence of pressure and temperature on the detonability of hydrogen-air-diluent mixtures diluted with steam or carbon dioxide. Detonation cell width measurements have been obtained from experiments conducted in a 0.43-m-diameter heated detonation tube. Calculations from a Zeldovich-von Neumann-Doring (ZND) model of a detonation with a detailed chemical-kinetic reaction mechanism for hydrogen oxidation are used to correlate the data. The data show a significant reduction in the ability of a diluent (excess air or hydrogen, carbon dioxide, or steam) to inhibit a detonation as the temperature is increased from 293 to 373 K. Only a small decrease in the cell width is observed with increasing pressure between approximately 1 and 3 atm for hydrogen-air mixtures diluted with steam or excess air. For conditions beyond which data exist, calculations based on the model yield results that indicate similar detonabilities of all mixtures considered at low initial pressures or high initial temperatures. Additionally, these results indicate minima in the cell width for variations in the initial pressure and temperature. The cell minima represent approximately the location of a change in a rate-limiting mechanism corresponding to the extended classical second-limit criterion. RP STAMPS, DW (reprint author), SANDIA NATL LABS,DIV 6463,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 39 TC 28 Z9 29 U1 0 U2 3 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 1991 VL 83 IS 3-4 BP 353 EP 364 DI 10.1016/0010-2180(91)90082-M PG 12 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA FE583 UT WOS:A1991FE58300015 ER PT J AU MARGOLIS, SB WILLIAMS, FA AF MARGOLIS, SB WILLIAMS, FA TI FLAME PROPAGATION IN SOLIDS AND HIGH-DENSITY FLUIDS WITH ARRHENIUS REACTANT DIFFUSION SO COMBUSTION AND FLAME LA English DT Article ID PROPELLANT COMBUSTION; ASYMPTOTIC THEORY; STABILITY; INSTABILITY; BIFURCATION; MODELS AB The combustion of solids and high-density fluids, such as the combustion synthesis of refractory materials or the high-pressure oxidation of organic compounds in supercritical water, is often characterized by a highly temperature-dependent mass diffusivity. In particular, the case of an Arrhenius dependence of this quantity on temperature is considered, where the activation energy of reactant diffusion is of the same order as that of the overall chemical reaction. Exploiting the asymptotic limit of large activation energies, it is shown that reactant diffusion becomes significant in the thin reaction zone, where a balance among convection, reaction, and diffusion is maintained. Relative to the case of either a zero or constant mass diffusion coefficient, this leads to modifications in the steady, planar flame-speed eigenvalue. A new asymptotic model is then derived that predicts corresponding shifts in the neutral stability boundary that marks the transition from steady to nonsteady modes of flame propagation. C1 UNIV CALIF SAN DIEGO,DEPT APPL MECH & ENGN SCI,LA JOLLA,CA 92093. RP MARGOLIS, SB (reprint author), SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551, USA. NR 17 TC 12 Z9 12 U1 0 U2 3 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 1991 VL 83 IS 3-4 BP 390 EP 398 DI 10.1016/0010-2180(91)90085-P PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA FE583 UT WOS:A1991FE58300018 ER PT J AU ZHANG, JZH AF ZHANG, JZH TI MULTICHANNEL QUANTUM WAVE PACKET PROPAGATION IN THE INTERACTION PICTURE - APPLICATION TO GAS SURFACE SCATTERING SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID DEPENDENT SCHRODINGER-EQUATION; ATOM-DIATOM COLLISIONS; TIME; MOLECULE; DYNAMICS; DISSOCIATION; INTEGRATION; FORMALISM; STATES; SYSTEM AB Propagation of quantum wave packet in the interaction picture substantially improves the efficiency of time-dependent quantum mechanical (TDQM) methods for solving various scattering or half scattering problems. This paper generalizes the idea in a straightforward manner to treat coupled channel quantum wave packet propagation when basis set expansions of the total wavefunction in certain degrees of freedom are desired. C1 UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RI Zhang, John/A-3372-2013 NR 33 TC 23 Z9 28 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 28 EP 37 DI 10.1016/0010-4655(91)90235-D PG 10 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000005 ER PT J AU BOTTCHER, C BOTTRELL, GJ STRAYER, MR AF BOTTCHER, C BOTTRELL, GJ STRAYER, MR TI TIME-DEPENDENT HARTREE-FOCK STUDIES OF ATOMIC-COLLISIONS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID IONIZATION AB The time-dependent Hartree-Fock method for atomic collisions is described, together with associated numerical techniques. Some applications, chiefly to ion-atom collisions, are presented. RP BOTTCHER, C (reprint author), OAK RIDGE NATL LAB, DIV PHYS, OAK RIDGE, TN 37831 USA. NR 23 TC 15 Z9 15 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 63 EP 70 DI 10.1016/0010-4655(91)90238-G PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000008 ER PT J AU UMAR, AS STRAYER, MR AF UMAR, AS STRAYER, MR TI NUMERICAL-METHODS FOR NUCLEAR MEAN-FIELD DYNAMICS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID DEPENDENT HARTREE-FOCK; DENSITY-MATRIX EXPANSION; HEAVY-ION COLLISIONS; SKYRMES INTERACTION; CROSS-SECTIONS; FUSION; O-16+O-16; APPROXIMATION; SYSTEM; CA-40+CA-40 AB We present an overview of the recent developments in the time-dependent mean-field description of nuclear dynamics. The emphasis is on the numerical aspects of such calculations. The derivation of the lattice equations and their solution is discussed in some detail. We introduce a new approach for performing highly accurate lattice calculations using the basis-spline collocation method. Applications to the study of fusion, deep-inelastic reactions, and nuclear molecules are presented. C1 OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. RP UMAR, AS (reprint author), VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235, USA. RI Umar, Ahmet/J-4125-2013 OI Umar, Ahmet/0000-0002-9267-5253 NR 55 TC 15 Z9 15 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 179 EP 202 DI 10.1016/0010-4655(91)90248-J PG 24 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000018 ER PT J AU PERNOT, P LESTER, WA CERJAN, C AF PERNOT, P LESTER, WA CERJAN, C TI QUANTUM TIME-DEPENDENT TREATMENT OF MOLECULAR-COLLISIONS - SCATTERING OF HE BY H-2(B-1-SIGMA-U+) SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID POTENTIAL-ENERGY SURFACES; SCHRODINGER-EQUATION; H-2(B1-SIGMA-U+) AB Computational limitations of using a time-dependent quantum method to study He + H2(B) scattering are presented with an analysis of the consequences of the approximation to a 2D model. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV PARIS 11,CHIM QUANT GRP,F-91405 ORSAY,FRANCE. UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720. RP PERNOT, P (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT CHEM SCI,BERKELEY,CA 94720, USA. RI PERNOT, Pascal/C-2643-2008 OI PERNOT, Pascal/0000-0001-8586-6222 NR 21 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 259 EP 264 DI 10.1016/0010-4655(91)90254-I PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000024 ER PT J AU SCHAFER, KJ KWONG, NH GARCIA, JD AF SCHAFER, KJ KWONG, NH GARCIA, JD TI DEVELOPMENT OF B-SPLINE TECHNIQUES FOR DYNAMIC ION METAL INTERACTION THEORIES SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID SURFACE SCATTERING; COLLISIONS; CHARGE; DENSITY AB A three-dimensional time-dependent mean-field (TDMF) treatment for this problem is made computationally feasible by careful use of symmetries, incorporation of B-spline techniques and operator splitting concepts in the development of the method. The TDMF theory used is an adaptation of time-dependent Hartree-Fock theory used in atomic and nuclear physics for dealing with similar short-duration, strong, nonlinear collision interactions. Results of preliminary numerical studies are described. C1 UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. RP SCHAFER, KJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV PHYS,LIVERMORE,CA 94550, USA. NR 21 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 306 EP 313 DI 10.1016/0010-4655(91)90257-L PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000027 ER PT J AU TISZAUER, DH KULANDER, KC AF TISZAUER, DH KULANDER, KC TI COMPUTATION METHODS EMPLOYED IN THE SELF-CONSISTENT TIME-DEPENDENT, HARTREE-FOCK CALCULATION FOR A REACTIVE MOLECULAR COLLISION SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID O-16 + O-16; APPROXIMATION; DYNAMICS; EQUATION; SYSTEMS; MODEL AB A fully self-consistent time-dependent Hartree-Fock calculation of the molecular reactive scattering system, collinear H+ + H2, has recently been shown to be a viable method for obtaining the reaction probability, charge exchange probability, and translational to vibrational energy transfer. The calculation couples the time-dependent Hartree-Fock equation for the electronic wavefunction, represented by a single Slater determinant, to the classical equations for the motion of the nuclei. This coupling is achieved by computing the force on the nuclei from the variation of the electronic energy at each time step. The nuclei's position and electronic wavefunction are co-propagated in time from the initial asymptotic scattering state until the collision products separate in the exit channel. In this self-consistent calculation one can identify four major parts that must be calculated concurrently. The first of these is the time propagation of the electronic wavefunction. The second is the determination of the forces on the nuclei from the variation of the electronic energy. The third is the solution of Poisson's equation for the electron-electron potential, V(e). The fourth is the propagation of the position and velocities of the nuclei according to the classical equations of motion. Each of these parts and their interrelation in the overall calculation is discussed here. C1 UNIV CALIF DAVIS,DAVIS,CA 95616. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. NR 35 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 351 EP 364 DI 10.1016/0010-4655(91)90262-J PG 14 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000032 ER PT J AU SCHAFER, KJ AF SCHAFER, KJ TI THE ENERGY ANALYSIS OF TIME-DEPENDENT NUMERICAL WAVE-FUNCTIONS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID ABOVE-THRESHOLD IONIZATION; HARTREE-FOCK CALCULATIONS; MULTIPHOTON IONIZATION; SCHRODINGER-EQUATION; SPECTRAL METHOD AB A new method for extracting energy-resolved quantities from a wave function calculated on a numerical grid is presented. The method is fast, flexible and is easily applied in multiple dimensions. A number of its features are illustrated via a calculation of the short-pulse laser ionization spectrum of hydrogen. This spectrum exhibits many narrow resonances, ranging over eight orders of magnitude in the continuum, as well as significant bound-state populations and so forms a rigorous test of the method. RP SCHAFER, KJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 16 TC 48 Z9 48 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 427 EP 434 DI 10.1016/0010-4655(91)90267-O PG 8 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000037 ER PT J AU NEUHAUSER, D BAER, M JUDSON, RS KOURI, DJ AF NEUHAUSER, D BAER, M JUDSON, RS KOURI, DJ TI THE APPLICATION OF TIME-DEPENDENT WAVEPACKET METHODS TO REACTIVE SCATTERING SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID WAVE-PACKET APPROACH; ARRANGEMENT-CHANNEL APPROACH; ACCURATE 3-DIMENSIONAL PROBABILITIES; POTENTIAL-ENERGY SURFACE; COLLINEAR H+H2 REACTION; FOURIER METHOD SOLUTION; SCHRODINGER-EQUATION; QUANTUM-MECHANICS; MOLECULAR-DYNAMICS; EXCHANGE PROCESSES AB In this article, we review several methods for performing numerically-exact reactive scattering calculations using time-dependent wavepackets. The basic idea we imply is to take the multi-arrangement reactive problem and reformulate it as one or more inelastic ones. In the simplest method, we extract total reaction probabilities by calculating the flux of the wavepacket as it leaves the interaction region in the direction of the reactive arrangement. To make this practical, we use complex potentials that absorbed the wavepacket before it reaches the numerical grid boundary. We describe methods that generate observables ranging from total, energy-averaged reaction probabilities up to energy- and state-resolved S-matrix elements. We also review techniques for efficiently performing the necessary inelastic wavepacket propagation. C1 SOREQ NUCL RES CTR,DEPT THEORET PHYS & APPL MATH,IL-70600 YAVNE,ISRAEL. SANDIA NATL LABS,LIVERMORE,CA 94550. UNIV HOUSTON,DEPT CHEM,HOUSTON,TX 77204. UNIV HOUSTON,DEPT PHYS,HOUSTON,TX 77204. RP NEUHAUSER, D (reprint author), PRINCETON UNIV,DEPT CHEM,PRINCETON,NJ 08544, USA. OI Judson, Richard/0000-0002-2348-9633 NR 101 TC 144 Z9 145 U1 2 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 460 EP 481 DI 10.1016/0010-4655(91)90270-U PG 22 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000040 ER PT J AU KULANDER, KC RESCIGNO, TN AF KULANDER, KC RESCIGNO, TN TI EFFECTIVE POTENTIALS FOR TIME-DEPENDENT CALCULATIONS OF MULTIPHOTON PROCESSES IN ATOMS SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID HARTREE-FOCK CALCULATIONS; EFFECTIVE CORE POTENTIALS; SCHRODINGER-EQUATION; HARMONIC-GENERATION; RARE-GASES; IONIZATION; LASER; COLLISIONS; RADIATION; HYDROGEN AB Time-dependent calculations of multiphoton processes in multielectron atoms can utilize effective potentials to reduce the calculation to one for a single electron. The time-dependent Schrodinger equation for the wavefunction of this electron is solved using a finite-difference, implicit integration scheme. From this time-dependent wave function we can extract cross-sections and/or rates for photoemission, excitation and ionization. The effective potentials are constructed from Hartree-Slater calculations on the ground state of the atoms. Illustrative results are presented. RP KULANDER, KC (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,THEORET ATOM & MOLEC PHYS GRP,LIVERMORE,CA 94550, USA. NR 28 TC 32 Z9 32 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 523 EP 528 DI 10.1016/0010-4655(91)90273-N PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000043 ER PT J AU CERJAN, C KULANDER, KC AF CERJAN, C KULANDER, KC TI EFFICIENT TIME PROPAGATION FOR FINITE-DIFFERENCE REPRESENTATIONS OF THE TIME-DEPENDENT SCHRODINGER-EQUATION SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID FOURIER METHOD SOLUTION; MULTIPHOTON IONIZATION; DYNAMICS AB The applicability of the Chebyshev time propagation algorithm for the solution of the time-dependent Schrodinger equation is investigated within the context of differencing schemes for the representation of the spatial operators. Representative numerical tests for the harmonic oscillator and Morse potentials display the utility and limitations of this combined approach. Substantial increases in time step are possible for these lower-order methods compared with other propagators commonly used in differencing schemes, but if very high accuracy is desired for these cases difference methods remain less efficient computationally than the corresponding spectral spatial representation when both methods are applicable. RP CERJAN, C (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 12 TC 19 Z9 19 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 529 EP 537 DI 10.1016/0010-4655(91)90274-O PG 9 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000044 ER PT J AU LIN, FJ MUCKERMAN, JT AF LIN, FJ MUCKERMAN, JT TI SOLUTION OF THE TIME-DEPENDENT SCHRODINGER-EQUATION EMPLOYING A BASIS OF EXPLICIT DISCRETE-COORDINATE EIGENFUNCTIONS - SPHERICAL AND AZIMUTHAL SYMMETRY, ADIABATICITY, AND MULTIPHOTON EXCITATION OF A ROTATING MORSE OSCILLATOR SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article ID MOLECULAR-DYNAMICS; PHOTON-ABSORPTION; QUANTUM; FIELD; TOOL AB We have recently presented a method for solving the time-dependent Schrodinger equation by collocation on various members of a family of spatial grids and have shown that this method is interpretable in terms of the expansion of the wave function in a basis of discrete coordinate eigenfunctions. The method is applicable to molecular systems with one or multiple spatial dimensions, and also to bound or unbound molecular systems. We now place the method in the more general setting of spatial grids belonging to the family of scaled Gauss-Markov quadrature points. Further, we now treat molecular systems described in terms of the more general case of a curvilinear coordinate system. This allows us to treat, for example, a system with spherical or azimuthal symmetry and to employ the information regarding the symmetry, i.e. transform from Cartesian coordinates to spherical polar coordinates and obtain the Schrodinger equation for a wave function for a configuration space with a lower number of dimensions. In addition, we describe a modified adiabatic approach for decreasing the number of spatial dimensions in the Hamiltonian appearing in the time-dependent Schrodinger equation for the wave function. We then obtain a coupled set of differential equations describing the time evolution of the molecular system, including the time-dependent Schrodinger equation in terms of the Hamiltonian with the lower number of spatial dimensions, and we apply our method for solving the time-evolution problem for the wave function by employing the Hamiltonian with that smaller number of spatial dimensions. Finally, we demonstrate the application of this extension of our collocation method to the nonlinear problem of multiple-photon excitation of a rotating anharmonic diatomic molecule by the explicitly time-dependent term describing irradiation of the molecule by an intense classical electromagnetic field. We compare our results for the quantal approach with our results for two approximate approaches: a modification of the adiabatic quantal approach and a variation of the Monte Carlo classical trajectory approach. RP LIN, FJ (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. RI Muckerman, James/D-8752-2013 NR 38 TC 19 Z9 19 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD FEB PY 1991 VL 63 IS 1-3 BP 538 EP 568 DI 10.1016/0010-4655(91)90275-P PG 31 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA FF110 UT WOS:A1991FF11000045 ER PT J AU JONES, RH FRIESEL, MA PATHANIA, R AF JONES, RH FRIESEL, MA PATHANIA, R TI EVALUATION OF STRESS-CORROSION CRACK INITIATION USING ACOUSTIC-EMISSION SO CORROSION LA English DT Article; Proceedings Paper CT CORROSION/90 CY APR, 1990 CL LAS VEGAS, NV DE ACOUSTIC EMISSION; CRACK INITIATION; STAINLESS STEEL; STATIC LOAD; STRESS CORROSION AB Acoustic emission response has been used to detect the development of short intergranular stress corrosion cracks in laboratory samples of sensitized type 304 (UNS(1) S30400) stainless steel (SS). Tests were conducted at 25-degrees-C in water containing either 15 ppm of Na2S2O3 or 100 ppm of NaCl. Cylindrical samples with piezoelectric detectors mounted on both ends and the corrosion cell confined to the gauge section were used. The dual detectors allowed discrimination between signals generated within the sample from those generated from the surroundings. It was found that intergranular stress corrosion cracks of 200 to 300-mu-m length by 100 to 200-mu-m depth could be reliably detected with this technique Shallow 10-mu-deep longitudinal flaws were also detected in tests conducted in the 100 ppm NaCl environment. C1 ELECT POWER RES INST, PALO ALTO, CA 94303 USA. RP JONES, RH (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 23 TC 21 Z9 22 U1 0 U2 5 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 SN 0010-9312 J9 CORROSION JI Corrosion PD FEB PY 1991 VL 47 IS 2 BP 105 EP 115 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA FX700 UT WOS:A1991FX70000005 ER PT J AU BERNSTEIN, G LABOV, S LANDIS, D MADDEN, N MILLET, I SILVER, E RICHARDS, P AF BERNSTEIN, G LABOV, S LANDIS, D MADDEN, N MILLET, I SILVER, E RICHARDS, P TI AUTOMATED TEMPERATURE REGULATION SYSTEM FOR ADIABATIC DEMAGNETIZATION REFRIGERATORS SO CRYOGENICS LA English DT Article DE MAGNETIC REFRIGERATOR; ADIABATIC DEMAGNETIZATION REFRIGERATOR; TEMPERATURE REGULATION AB A temperature control system was constructed for an adiabatic demagnetization refrigerator operating between 50 mK and 4 K. The control algorithm is discussed and the system performance is presented. A temperature stability of 2-mu-K RMS at 100 mK has been maintained for more than 8 h. To improve the thermodynamic efficiency, the magnetic field is used as the control parameter, rather than resistive heating. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. NR 9 TC 7 Z9 7 U1 0 U2 1 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0011-2275 J9 CRYOGENICS JI Cryogenics PD FEB PY 1991 VL 31 IS 2 BP 99 EP 101 DI 10.1016/0011-2275(91)90253-S PG 3 WC Thermodynamics; Physics, Applied SC Thermodynamics; Physics GA EV053 UT WOS:A1991EV05300004 ER PT J AU ELLINGEN, DC AF ELLINGEN, DC TI DESIGNING YOUR 1ST ... OR YOUR NEXT ... DATABASE SO DATABASE LA English DT Article RP ELLINGEN, DC (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,ELECTR COMMERCE ELECTR DATA INTERCHANGE PROJECT,POB 808,LIVERMORE,CA 94550, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ONLINE INC PI WILTON PA 462 DANBURY RD, WILTON, CT 06897-2126 SN 0162-4105 J9 DATABASE JI Database PD FEB PY 1991 VL 14 IS 1 BP 90 EP 93 PG 4 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA ET556 UT WOS:A1991ET55600019 ER PT J AU ROSEN, JF MARKOWITZ, ME BIJUR, PE JENKS, ST WIELOPOLSKI, L KALEFEZRA, JA SLATKIN, DN AF ROSEN, JF MARKOWITZ, ME BIJUR, PE JENKS, ST WIELOPOLSKI, L KALEFEZRA, JA SLATKIN, DN TI SEQUENTIAL MEASUREMENTS OF BONE LEAD CONTENT BY L X-RAY-FLUORESCENCE IN CANA2EDTA-TREATED LEAD-TOXIC CHILDREN SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article ID BLOOD LEAD; INVIVO MEASUREMENT; EXPOSURE; HEALTH AB With the development of L X-ray fluorescence (LXRF) to measure cortical bone lead directly, safely, rapidly, and noninvasively, the present study was undertaken to a) evaluate LXRF as a possible replacement for the CaNa2EDTA test; b) quantify lead in tibial cortical bones of mildly to moderately lead-toxic children before treatment; and c) quantify lead in tibial cortical bones of lead-toxic children sequentially following one to two courses of chelation therapy. The clinical research design was based upon a longitudinal assessment of 59 untreated lead-toxic children. At enrollment, if the blood lead (PbB) was 25 to 55-mu-g/dL and the erythrocyte protoporphyrin (EP) concentration was greater-than-or-equal-to 35-mu-g/dL, LXRF measurement of tibial bone lead was carried out. One day later, each child underwent a CaNa2EDTA provocative test. If this test was positive, lead-toxic children were admitted to the hospital for 5 days of CaNa2EDTA therapy. These tests were repeated 6 weeks and 6 months after enrollment. Abatement of lead paint hazards was achieved in most apartments by the time of initial hospital discharge. The LXRF instrument consists of a low energy X-ray generator with a silver anode, a lithium-doped silicon detector, a polarizer of incident photons, and a multichannel X-ray analyzer. Partially polarized photons are directed at the subcutaneous, medial mid-tibial cortical bone. The LXRF spectrum, measured 90-degrees from the incident beam, reveals a peak in the 10.5 KeV region, which represents the lead L-alpha line. The effective dose equivalent using tissue weighting factors according to guidelines of the National Council on Radiation Protection and Measurements (1989), was 2.5-mu-Sv. The reproducibility of replicate LXRF measurements, including the day-to-day variation of the instrument, in 26 lead-toxic children, after repositioning the instrument within 5 cm of the first LXRF measurements, was +/- 9.2 (95% confidence limits). For an overlying tibial skin thickness of 5 mm, the minimum detection limit was 7-mu-g of lead/g (wet weight) at the 95% confidence interval. Based upon a discriminant analysis, 90% of lead-toxic children were predicted correctly as being CaNa2EDTA-positive or CaNa2EDTA-negative. Using LXRF and PbB values to predict CaNa2EDTA outcomes, the specificity and sensitivity of these two predictors were 86 and 93%, respectively. In a significant fraction of CaNa2EDTA-positive and CaNa2EDTA-negative children, cortical bone lead values were similar to lead concentrations measured via bone biopsy in normal adults and lead workers in industry. By 24 weeks after enrollment, PbB, EP, and urinary lead/EDTA ratios were similar in all groups. The most dramatic decreases in net corrected photon counts by LXRF occurred in children treated twice. Mean values of cortical bone lead by LXRF at 24 weeks in all three groups of children were similar to the mean concentration in untreated CaNa2EDTA-negative children at enrollment but still three to five times greater than those measured in the tibia or whole teeth of normal European children using atomic absorption. In lead-toxic children who did not qualify for treatment, additional significant accumulation of lead in bone ended once children were removed from leaded environments or returned to lead-abated apartments. These data suggest that LXRF measurements of lead in tibial cortical bone have considerable promise to replace the CaNa2EDTA test and to provide a more appropriate end point of chelation therapy than the conventional indices of PbB and EP. Moreover, markedly elevated bone lead values accumulated during early childhood may have an intergenerational impact, as maternal lead stores amassed during childhood cross the placenta and directly affect the developing fetus. C1 MONTEFIORE MED CTR,ALBERT EINSTEIN COLL MED,DIV EPIDEMIOL,BRONX,NY 10467. SUNY STONY BROOK,DEPT RADIAT ONCOL,STONY BROOK,NY 11794. UNIV IOANNINA,SCH MED,MED PHYS LAB,IOANNINA,GREECE. BROOKHAVEN NATL LAB,DEPT MED,UPTON,NY 11973. RP ROSEN, JF (reprint author), MONTEFIORE MED CTR,ALBERT EINSTEIN COLL MED,DEPT PEDIAT,DIV PEDIAT METAB,BRONX,NY 10467, USA. FU NIEHS NIH HHS [ES04039] NR 28 TC 13 Z9 13 U1 0 U2 1 PU NATL INST ENVIRON HEALTH SCI PI RES TRIANGLE PK PA PO BOX 12233, RES TRIANGLE PK, NC 27709 SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD FEB PY 1991 VL 91 BP 57 EP 62 DI 10.2307/3430983 PG 6 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA FD604 UT WOS:A1991FD60400008 PM 1904023 ER PT J AU MCCABE, GH AF MCCABE, GH TI MIXED WASTES SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Letter RP MCCABE, GH (reprint author), BATTELLE SEATTLE RES CTR,SEATTLE,WA 98105, USA. NR 1 TC 0 Z9 0 U1 0 U2 0 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 1991 VL 25 IS 2 BP 192 EP 192 PG 1 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA EV665 UT WOS:A1991EV66500002 ER PT J AU HALL, MJ LUCAS, D KOSHLAND, CP AF HALL, MJ LUCAS, D KOSHLAND, CP TI MEASURING CHLORINATED HYDROCARBONS IN COMBUSTION BY USE OF FOURIER-TRANSFORM INFRARED-SPECTROSCOPY SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article AB The quantitative measurement of products of incineration of chlorinated hydrocarbons using Fourier transform infrared (FTIR) spectrometery was evaluated during a study of the fundamental processes of toxic waste incineration. Combustion products were sampled from a turbulent flow reactor into which chlorinated hydrocarbons were injected. Chlorinated species were detected mainly in the C-Cl stretching region, away from H2O and CO2 interferences. Absorbances of species having rotational lines narrower than the instrument resolution, such as CO, CO2, and HCl, were nonlinear under most conditions. The measured absorbance of these species was very sensitive to total pressure, increasing with an increase in total pressure; at very low optical densities, however, absorbance became independent of total pressure. Thus, while FTIR spectroscopy has many features that make it attractive for measuring combustion species, care must be taken to ensure the accuracy of quantitative measurements. C1 UNIV CALIF BERKELEY,DEPT BIOMED & ENVIRONM HLTH SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MECH ENGN,BERKELEY,CA 94720. NR 32 TC 23 Z9 23 U1 0 U2 1 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 1991 VL 25 IS 2 BP 260 EP 267 DI 10.1021/es00014a007 PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA EV665 UT WOS:A1991EV66500012 ER PT J AU LEE, JH CHEN, YZ TANG, IN AF LEE, JH CHEN, YZ TANG, IN TI HETEROGENEOUS LOSS OF GASEOUS H2O2 IN ATMOSPHERIC AIR SAMPLING SYSTEM SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID PHASE HYDROGEN-PEROXIDE; AQUEOUS OXIDATION; SULFUR-DIOXIDE; TROPOSPHERE; OZONE; ACID; SO2 AB The extent of gaseous H2O2 losses in the sampling line of a fluorometric detector was investigated extensively. In some cases, as much as 90% of the gaseous H2O2 was lost by surface reactions taking place at the inlet region of the sampling line. Gaseous H2O2 measurement was found to be dependent not only on the sampling line cleanness, but on the ambient conditions as well. The generally adopted procedure using aqueous-phase H2O2 standards to calibrate the system is shown to be unsatisfactory. Instead, gas-phase H2O2 calibration is required for quantitative ambient measurements, and an effective procedure is recommended herein. RP LEE, JH (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,DIV ENVIRONM CHEM,UPTON,NY 11973, USA. NR 22 TC 31 Z9 31 U1 0 U2 1 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 1991 VL 25 IS 2 BP 339 EP 342 DI 10.1021/es00014a019 PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA EV665 UT WOS:A1991EV66500024 ER PT J AU RAYNER, S AF RAYNER, S TI MANAGING THE GLOBAL COMMONS - INTRODUCTION SO EVALUATION REVIEW LA English DT Editorial Material RP RAYNER, S (reprint author), OAK RIDGE NATL LAB,CTR GLOBAL ENVIRONM STUDIES,OAK RIDGE,TN 37831, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 0193-841X J9 EVALUATION REV JI Eval. Rev. PD FEB PY 1991 VL 15 IS 1 BP 3 EP 6 DI 10.1177/0193841X9101500101 PG 4 WC Social Sciences, Interdisciplinary SC Social Sciences - Other Topics GA ET875 UT WOS:A1991ET87500001 ER PT J AU RAYNER, S AF RAYNER, S TI A CULTURAL-PERSPECTIVE ON THE STRUCTURE AND IMPLEMENTATION OF GLOBAL ENVIRONMENTAL AGREEMENTS SO EVALUATION REVIEW LA English DT Article; Proceedings Paper CT INTERNATIONAL WORKSHOP ON MANAGING THE GLOBAL COMMONS : DECISION MAKING AND CONFLICT RESOLUTION IN RESPONSE TO CLIMATE CHANGE CY AUG 01-04, 1989 CL KNOXVILLE, TN SP GLOBAL ENVIRONM STUDIES CTR, OAK RIDGE NATL LAB, UNIV TENNESSEE, ENERGY ENVIRONM & RESOURCES CTR C1 OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831. RP RAYNER, S (reprint author), OAK RIDGE NATL LAB,CTR GLOBAL ENVIRONM STUDIES,OAK RIDGE,TN 37831, USA. OI rayner, steve/0000-0001-6779-9345 NR 49 TC 29 Z9 29 U1 0 U2 0 PU SAGE SCIENCE PRESS PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 SN 0193-841X J9 EVALUATION REV JI Eval. Rev. PD FEB PY 1991 VL 15 IS 1 BP 75 EP 102 DI 10.1177/0193841X9101500105 PG 28 WC Social Sciences, Interdisciplinary SC Social Sciences - Other Topics GA ET875 UT WOS:A1991ET87500005 ER PT J AU AUKERMAN, MJ SCHMIDT, RJ BURR, B BURR, FA AF AUKERMAN, MJ SCHMIDT, RJ BURR, B BURR, FA TI AN ARGININE TO LYSINE SUBSTITUTION IN THE BZIP DOMAIN OF AN OPAQUE-2 MUTANT IN MAIZE ABOLISHES SPECIFIC DNA-BINDING SO GENES & DEVELOPMENT LA English DT Article DE TRANSCRIPTION FACTOR; ZEA-MAYS; SEED STORAGE PROTEIN; BZIP DOMAIN; DNA BINDING; ZEIN GENES ID NUCLEAR FACTOR CREB; ONCOGENE V-JUN; LEUCINE ZIPPER; NUCLEOTIDE-SEQUENCE; ZEIN GENES; C-FOS; PROTEIN; ENCODES; ENDOSPERM; REGIONS AB The opaque-2 (o2) locus in maize encodes a transcription factor involved in the regulation of zein storage proteins. We have shown previously that the O2 protein contains a leucine zipper domain that binds to promoters of 22-kD zein genes. In this paper we characterize an EMS-induced o2 allele, o2-676, that causes a 50% reduction in zein. We have found that the o2-676 mutant protein does not show specific recognition of zein promoter fragments because of the substitution of a lysine residue for an arginine residue within the bZIP domain of o2-676. This particular arginine is conserved within the bZIP domains of all mammalian, fungal, and plant DNA binding proteins of this class. The correlation between this mutation in o2 and the altered pattern of zein expression strongly suggests that O2 regulates transcription of certain members of the zein multigene family through direct interaction with the zein promoters and not through the transcriptional activation of some other regulator of zein gene expression. C1 UNIV CALIF SAN DIEGO,DEPT BIOL,C-016,LA JOLLA,CA 92093. UNIV CALIF SAN DIEGO,CTR MOLEC GENET,LA JOLLA,CA 92093. BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973. FU NIGMS NIH HHS [GM07313, GM31093, GM41286] NR 54 TC 62 Z9 66 U1 0 U2 0 PU COLD SPRING HARBOR LAB PRESS PI PLAINVIEW PA 1 BUNGTOWN RD, PLAINVIEW, NY 11724 SN 0890-9369 J9 GENE DEV JI Genes Dev. PD FEB PY 1991 VL 5 IS 2 BP 310 EP 320 DI 10.1101/gad.5.2.310 PG 11 WC Cell Biology; Developmental Biology; Genetics & Heredity SC Cell Biology; Developmental Biology; Genetics & Heredity GA EX518 UT WOS:A1991EX51800015 PM 1899843 ER PT J AU DAVIS, LM FAIRFIELD, FR HARGER, CA JETT, JH KELLER, RA HAHN, JH KRAKOWSKI, LA MARRONE, BL MARTIN, JC NUTTER, HL RATLIFF, RL SHERA, EB SIMPSON, DJ SOPER, SA AF DAVIS, LM FAIRFIELD, FR HARGER, CA JETT, JH KELLER, RA HAHN, JH KRAKOWSKI, LA MARRONE, BL MARTIN, JC NUTTER, HL RATLIFF, RL SHERA, EB SIMPSON, DJ SOPER, SA TI RAPID DNA SEQUENCING BASED UPON SINGLE MOLECULE DETECTION SO GENETIC ANALYSIS-BIOMOLECULAR ENGINEERING LA English DT Article ID LASER-INDUCED FLUORESCENCE; SAMPLES; PROCESSIVITY AB We are developing a laser-based technique for the rapid sequencing of 40-kb or larger fragments of DNA at a rate of 100 to 1000 bases per second. The approach relies on fluorescent labeling of the bases in a single fragment of DNA, attachment of this labeled DNA fragment to a support, movement of the supported DNA fragment into a flowing sample stream, and detection of individual fluorescently labeled bases as they are cleaved from the DNA fragment by an exonuclease. The ability to sequence large fragments of DNA will significantly reduce the amount of subcloning and the number of overlapping sequences required to assemble megabase segments of sequence information. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR HUMAN GENOME STUDIES,LOS ALAMOS,NM 87545. RI Davis, Lloyd/D-7648-2013 OI Davis, Lloyd/0000-0002-3169-3044 NR 18 TC 42 Z9 42 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1050-3862 J9 GENET ANAL-BIOMOL E JI Genet. Anal.-Biomol. Eng. PD FEB PY 1991 VL 8 IS 1 BP 1 EP 7 DI 10.1016/1050-3862(91)90002-9 PG 7 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA FG992 UT WOS:A1991FG99200001 PM 2043380 ER PT J AU CHESSER, RK AF CHESSER, RK TI GENE DIVERSITY AND FEMALE PHILOPATRY SO GENETICS LA English DT Article ID TAILED PRAIRIE DOG; F-STATISTICS; SUBDIVIDED POPULATIONS; RHESUS-MONKEYS; MIGRATION; MAMMALS; MODEL AB The effect of female philopatry on the apportionment of gene diversity within a population is evaluated. Even with random mate selection, the apportionment of gene diversity within and among social lineages (groups of related females) is inherently different than in classically defined demic groups. Considerable excess heterozygosity occurs within lineages without substantial changes in total or population heterozygosity. The proportion of genetic variance among lineages within the population was dependent on the lineage size and the number of male breeders per lineage. The greatest genetic differentiation among lineages was evident when there was one polygynous male breeding within a lineage of philopatric females, a common breeding tactic in mammalian social systems. The fixation indices depicting the genetic structure of the population were found to attain constant values after the first few generations despite the continuous loss of gene diversity within the population by genetic drift. Additionally, the change of gene correlations within individuals relative to the change within the population attains a state of dynamic equilibrium, as do the changes of gene correlations within lineages relative to the total and within individuals relative to within lineages. Comparisons of coancestries and fixation indices for philopatric versus randomly dispersing females indicate that philopatry and polygyny have probably not evolved independently and that promotion of gene correlations among adults rather than offspring has been of primary importance. C1 UNIV GEORGIA,DEPT GENET,ATHENS,GA 30602. RP CHESSER, RK (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER F,AIKEN,SC 29802, USA. NR 45 TC 210 Z9 214 U1 1 U2 19 PU GENETICS PI BALTIMORE PA 428 EAST PRESTON ST, BALTIMORE, MD 21202 SN 0016-6731 J9 GENETICS JI Genetics PD FEB PY 1991 VL 127 IS 2 BP 437 EP 447 PG 11 WC Genetics & Heredity SC Genetics & Heredity GA EV664 UT WOS:A1991EV66400019 PM 2004714 ER PT J AU OVNIC, M TEPPERMAN, K MEDDA, S ELLIOTT, RW STEPHENSON, DA GRANT, SG GANSCHOW, RE AF OVNIC, M TEPPERMAN, K MEDDA, S ELLIOTT, RW STEPHENSON, DA GRANT, SG GANSCHOW, RE TI CHARACTERIZATION OF A MURINE CDNA-ENCODING A MEMBER OF THE CARBOXYLESTERASE MULTIGENE FAMILY SO GENOMICS LA English DT Article ID AMINO-ACID SEQUENCE; MOUSE MUS-MUSCULUS; 60-KILODALTON GLYCOPROTEIN ESTERASE; 2ND TRIMERIC CARBOXYLESTERASE; LIVER MICROSOMAL-MEMBRANES; RECOMBINANT INBRED STRAINS; HOUSE MOUSE; MESSENGER-RNA; BETA-GLUCURONIDASE; 60-KDA PROTEINS C1 NIDDKD,GENET & BIOCHEM BRANCH,BETHESDA,MD 20892. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. UNIV CINCINNATI,DEPT BIOL SCI,CINCINNATI,OH 45221. NEW YORK STATE DEPT HLTH,ROSWELL PK MEM INST,DEPT MOLEC & CELLULAR BIOL,BUFFALO,NY 14263. RP OVNIC, M (reprint author), CHILDRENS HOSP MED CTR,INST DEV RES,ELLAND & BETHESDA AVE,CINCINNATI,OH 45229, USA. RI Grant, Stephen/D-6984-2014 OI Grant, Stephen/0000-0002-9236-0913 FU NIDDK NIH HHS [DK 14770]; NIGMS NIH HHS [GM 36366, GM 28464] NR 55 TC 60 Z9 61 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 PY 1991 VL 9 IS 2 BP 344 EP 354 DI 10.1016/0888-7543(91)90263-E PG 11 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA EU767 UT WOS:A1991EU76700019 PM 1840565 ER PT J AU BURNHAM, AK SWEENEY, JJ AF BURNHAM, AK SWEENEY, JJ TI A CHEMICAL KINETIC-MODEL OF VITRINITE MATURATION AND REFLECTANCE - REPLY SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Letter RP BURNHAM, AK (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 4 TC 5 Z9 5 U1 0 U2 2 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 1991 VL 55 IS 2 BP 643 EP 644 DI 10.1016/0016-7037(91)90018-Z PG 2 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA EY119 UT WOS:A1991EY11900018 ER PT J AU RENEAU, SL OBERLANDER, TM HARRINGTON, CD AF RENEAU, SL OBERLANDER, TM HARRINGTON, CD TI ACCELERATOR MASS-SPECTROMETRY RADIOCARBON DATING OF ROCK VARNISH - DISCUSSION SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Discussion ID CALIFORNIA C1 UNIV CALIF BERKELEY,DEPT GEOG,BERKELEY,CA 94720. RP RENEAU, SL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRONM SCI,MS D462,LOS ALAMOS,NM 87545, USA. NR 12 TC 11 Z9 11 U1 0 U2 0 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 1991 VL 103 IS 2 BP 310 EP 314 DI 10.1130/0016-7606(1991)103<0310:AMSRDO>2.3.CO;2 PG 5 WC Geosciences, Multidisciplinary SC Geology GA EV833 UT WOS:A1991EV83300012 ER PT J AU SCHURAYTZ, BC VOGEL, TA YOUNKER, LW AF SCHURAYTZ, BC VOGEL, TA YOUNKER, LW TI ND ISOTOPIC GRADIENTS IN UPPER CRUSTAL MAGMA CHAMBERS - EVIDENCE FOR INSITU MAGMA-WALL-ROCK INTERACTION - COMMENT SO GEOLOGY LA English DT Letter ID SOUTHWESTERN NEVADA C1 MICHIGAN STATE UNIV,DEPT GEOL SCI,E LANSING,MI 48824. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DEPT EARTH SCI,LIVERMORE,CA 94550. RP SCHURAYTZ, BC (reprint author), LUNAR & PLANETARY INST,3303 NASA RD 1,HOUSTON,TX 77058, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU GEOLOGICAL SOC AMERICA PI BOULDER PA PO BOX 9140 3300 PENROSE PLACE, BOULDER, CO 80301 SN 0091-7613 J9 GEOLOGY JI Geology PD FEB PY 1991 VL 19 IS 2 BP 185 EP & DI 10.1130/0091-7613(1991)019<0185:CARONI>2.3.CO;2 PG 0 WC Geology SC Geology GA EV835 UT WOS:A1991EV83500022 ER PT J AU BROWN, SR SCHOLZ, CH RUNDLE, JB AF BROWN, SR SCHOLZ, CH RUNDLE, JB TI A SIMPLIFIED SPRING-BLOCK MODEL OF EARTHQUAKES SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SELF-ORGANIZED CRITICALITY AB The time interval between earthquakes is much larger than the actual time involved during slip in an individual event. We have used this fact to construct a cellular automaton model of earthquakes. This model describes the time evolution of a 2-D system of coupled masses and springs sliding on a frictional surface. The model exhibits power law frequency-size relations and can exhibit large earthquakes with the same scatter in the recurrence time observed for actual earthquakes. C1 COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP BROWN, SR (reprint author), SANDIA NATL LABS,DIV 6232,ALBUQUERQUE,NM 87185, USA. NR 18 TC 106 Z9 107 U1 0 U2 12 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 PY 1991 VL 18 IS 2 BP 215 EP 218 DI 10.1029/91GL00210 PG 4 WC Geosciences, Multidisciplinary SC Geology GA EY529 UT WOS:A1991EY52900025 ER PT J AU REED, MJ AF REED, MJ TI GEOTHERMAL-ENERGY SO GEOTIMES LA English DT Article RP REED, MJ (reprint author), US DOE,DIV GEOTHERMAL,WASHINGTON,DC 20585, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 SN 0016-8556 J9 GEOTIMES JI Geotimes PD FEB PY 1991 VL 36 IS 2 BP 16 EP 18 PG 3 WC Geosciences, Multidisciplinary SC Geology GA EZ384 UT WOS:A1991EZ38400011 ER PT J AU JAGUST, WJ EBERLING, JL AF JAGUST, WJ EBERLING, JL TI MRI, CT, SPECT, PET - THEIR USE IN DIAGNOSING DEMENTIA SO GERIATRICS LA English DT Article ID POSITRON EMISSION TOMOGRAPHY; ALZHEIMERS-DISEASE; MAGNETIC-RESONANCE; COMPUTED-TOMOGRAPHY; METABOLISM; ATROPHY C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DONNER LAB,FAC MED,BERKELEY,CA 94720. RP JAGUST, WJ (reprint author), UNIV CALIF DAVIS,SCH MED,DAVIS,CA 95616, USA. NR 20 TC 22 Z9 22 U1 0 U2 2 PU ADVANSTAR COMMUNICATIONS PI DULUTH PA 131 W FIRST ST, DULUTH, MN 55802 SN 0016-867X J9 GERIATRICS JI Geriatrics PD FEB PY 1991 VL 46 IS 2 BP 28 EP & PG 0 WC Geriatrics & Gerontology SC Geriatrics & Gerontology GA EX381 UT WOS:A1991EX38100002 PM 1991619 ER PT J AU LEGGETT, RW WILLIAMS, LR AF LEGGETT, RW WILLIAMS, LR TI SUGGESTED REFERENCE VALUES FOR REGIONAL BLOOD VOLUMES IN HUMANS SO HEALTH PHYSICS LA English DT Article ID EMISSION TOMOGRAPHY; OXYGEN UTILIZATION; CARDIAC-OUTPUT; PULMONARY; FLOW; HEMATOCRIT; RADIONUCLIDE; VOLUNTEERS; EXERCISE; FAILURE AB Estimates of regional blood volumes (BVs) in man are needed for the dosimetry of radionuclides that decay in the circulation to a significant extent. The tabulation of regional BVs in Publication No. 23 of the International Commission on Radiological Protection (ICRP Reference Man document) may be the best available for dosimetric applications but is not consistent with current information for some organs and does not address some important blood pools. The purpose of this paper is to suggest an improved set of reference values for regional BVs in adult humans. The total blood volume (TBV) is viewed as comprising 22 separate pools, including several pools not addressed in the ICRP Reference Man document. Values suggested here for brain, liver, skin, active marrow, inactive marrow, and bone differ by at least a factor of two from those given for ICRP Reference Man. C1 INDIANA UNIV, DEPT MATH & COMP SCI, S BEND, IN 46634 USA. RP LEGGETT, RW (reprint author), OAK RIDGE NATL LAB, DIV HLTH & SAFETY RES, METAB & DOSIMETRY RES GRP, OAK RIDGE, TN 37831 USA. NR 154 TC 37 Z9 38 U1 0 U2 5 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 1991 VL 60 IS 2 BP 139 EP 154 DI 10.1097/00004032-199102000-00001 PG 16 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 EV836 UT WOS:A1991EV83600002 PM 1989937 ER PT J AU LUCAS, HF AF LUCAS, HF TI RA-226 WHOLE-BODY GAMMA COUNTING AND RN-222 BREATH ANALYSIS - REPORT ON A SUBJECT EXPOSED TO URANIUM MILL TAILINGS SO HEALTH PHYSICS LA English DT Article AB One of two boys born in September 1949 who played on U mill tailings between age 8 and 12 was diagnosed as having leukemia at age 15.5. The exposed and control subjects were well matched; they were approximately the same age and both were 1.85 m (6' 1") in height and weighed 75.2 kg (165 pounds). The result obtained by gamma spectrometric method for the exposed subject was 0 +/- 17 Bq (0 +/- 470 pCi), while that for the control subject was 4 +/- 15 Bq (100 +/- 400 pCi). The result obtained by the Rn breath method for the exposed subject was 4.4 +/- 0.7 Bq (120 +/- 20 pCi), while that for the control was 5.4 +/- 1.4 Bq (150 +/- 38 pCi). These results suggest that the Ra-226 body burden of the exposed subject is within the range of those observed in subjects exposed only through normal food sources, which have a mean Ra-226 content of 1.5 Bq (range: 0.4-4.4 Bq) so that no significant mill-tailing intake is indicated. The best estimate of alpha particle dose to the red marrow from Ra-226 and its decay products was 0.05 mGy at age 14 and 0.10 mGy at age 38. This dose, when compared to that observed in the dial painters, suggests that the leukemia was not caused by uptake of Ra from the mill tailings. RP LUCAS, HF (reprint author), ARGONNE NATL LAB, DIV BIOL & MED RES, ARGONNE, IL 60439 USA. NR 17 TC 2 Z9 2 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 1991 VL 60 IS 2 BP 163 EP 167 DI 10.1097/00004032-199102000-00003 PG 5 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 EV836 UT WOS:A1991EV83600004 PM 1989938 ER PT J AU SCARPITTA, SC HARLEY, NH AF SCARPITTA, SC HARLEY, NH TI AN IMPROVED RN-222 CANISTER USING A 2-STAGE CHARCOAL SYSTEM SO HEALTH PHYSICS LA English DT Article ID ACTIVATED CARBON; FLUCTUATING CONCENTRATIONS; ADSORPTION AB A prototype for an improved passive Rn-222 canister (R-Canister) was designed and compared to conventional charcoal canisters for its adsorptive and desorptive characteristics following exposures to Rn-222 at 23-degrees-C in the presence of water vapor. The R-Canister, containing a two-stage charcoal system, minimizes the adverse effects of water vapor by maintaining the amount of adsorbed water vapor in the primary Rn adsorbent below the "break-point" of the charcoal. This is achieved by the placement of a desiccant charcoal cartridge 6 cm above the primary Rn adsorbent. The optimal bed depth of the primary adsorbent, determined from a diffusion study, was found to be 2.3 cm. The measured value for the effective diffusion coefficient of Rn in a peat-based charcoal at 15% humidity and 25-degrees-C is 7.97 x 10-10 m2s-1. Exposures to 70% humidity for 7 d increased the buildup time-constant of Rn in the R-Canisters by 33% as compared to R-Canisters exposed to 15% humidity. At relative humidities ranging from 15-70%, the Rn-222 buildup time-constant of the R-Canister ranged from 43-94 h, whereas the desorption time-constant ranged from 46-64 h. Typical buildup time-constants and desorption time-constants for conventional fully-opened charcoal canisters currently in field use ranged from 30-43 h and 17-29 h, respectively, over the same range of humidities. C1 NYU MED CTR, DEPT ENVIRONM MED, NEW YORK, NY 10016 USA. RP SCARPITTA, SC (reprint author), US DOE, ENVIRONM MEASUREMENTS LAB, 376 HUDSON ST, NEW YORK, NY 10014 USA. NR 19 TC 12 Z9 12 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 1991 VL 60 IS 2 BP 177 EP 188 DI 10.1097/00004032-199102000-00005 PG 12 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 EV836 UT WOS:A1991EV83600006 PM 1989939 ER PT J AU WILSON, DL GAMMAGE, RB DUDNEY, CS SAULTZ, RJ AF WILSON, DL GAMMAGE, RB DUDNEY, CS SAULTZ, RJ TI SUMMERTIME ELEVATION OF RN-222 LEVELS IN HUNTSVILLE, ALABAMA SO HEALTH PHYSICS LA English DT Article ID GEOLOGY; SOIL AB Indoor Rn concentrations and Rn in adjacent karst terrains were studied at four houses with crawlspaces in Huntsville, AL. In warm summertime weather, Rn-rich air may vent through limestone solution cavities exposed as holes at the surface of the properties. A probable interrelated-finding is that the indoor levels of Rn-222 are distinctly higher in the summer than winter. The karst underlying the homes is structurally faulted and, in all probability, facilitates Rn transport from the solution cavities to the crawlspaces. Abrupt day-to-day changes in indoor Rn concentrations were recorded in addition to large seasonal changes. If the owners or residents of these particular homes had attempted to make, and interpret, short-term screening measurements for Rn during the fall season, problems, including false negatives, could have arisen because of order-of-magnitude changes in Rn concentration occurring over a few days. The best time of year to make screening measurements would be during the summer when indoor Rn concentrations are more likely to reach their maximum values. RP WILSON, DL (reprint author), OAK RIDGE NATL LAB, MEASUREMENT SYST RES GRP, POB 2008, BLDG 7509, MS 6383, OAK RIDGE, TN 37831 USA. NR 14 TC 19 Z9 19 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 1991 VL 60 IS 2 BP 189 EP 197 DI 10.1097/00004032-199102000-00006 PG 9 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 EV836 UT WOS:A1991EV83600007 PM 1989940 ER PT J AU SAMET, JM STOLWIJK, J ROSE, SL AF SAMET, JM STOLWIJK, J ROSE, SL TI INTERNATIONAL WORKSHOP ON RESIDENTIAL RN EPIDEMIOLOGY - SUMMARY SO HEALTH PHYSICS LA English DT Note C1 UNIV NEW MEXICO, DEPT MED, ALBUQUERQUE, NM 87131 USA. YALE UNIV, SCH MED, DEPT EPIDEMIOL & PUBL HLTH, NEW HAVEN, CT 06510 USA. US DOE, OFF HLTH & ENVIRONM RES, WASHINGTON, DC 20545 USA. RP SAMET, JM (reprint author), UNIV NEW MEXICO, CTR CANC, NEW MEXICO TUMOR REGISTRY, ALBUQUERQUE, NM 87131 USA. NR 0 TC 28 Z9 28 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 1991 VL 60 IS 2 BP 223 EP 227 DI 10.1097/00004032-199102000-00010 PG 5 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 EV836 UT WOS:A1991EV83600011 PM 1671220 ER PT J AU SCARPITTA, SC HARLEY, NH AF SCARPITTA, SC HARLEY, NH TI RADON CALIBRATION FACTOR FOR CHARCOAL CANISTERS SO HEALTH PHYSICS LA English DT Letter ID ACTIVATED CARBON; ADSORPTION C1 NYU MED CTR, DEPT ENVIRONM MED, NEW YORK, NY 10016 USA. RP SCARPITTA, SC (reprint author), US DOE, ENVIRONM MEASUREMENTS LAB, 376 HUDSON ST, NEW YORK, NY 10014 USA. NR 11 TC 5 Z9 5 U1 1 U2 1 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 1991 VL 60 IS 2 BP 276 EP 278 PG 3 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 EV836 UT WOS:A1991EV83600020 PM 1989950 ER PT J AU HJERESEN, DL AF HJERESEN, DL TI NO EVIDENCE FOR MICROWAVE INTERACTION WITH NORADRENERGIC NEUROTRANSMITTER SYSTEMS - REPLY SO HEALTH PHYSICS LA English DT Letter RP HJERESEN, DL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, MAIL STOP M-899, LOS ALAMOS, NM 87545 USA. NR 1 TC 1 Z9 1 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 1991 VL 60 IS 2 BP 284 EP 284 PG 1 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 EV836 UT WOS:A1991EV83600025 ER PT J AU KELLY, MA MCIVER, JK SHEA, RF HAGER, GD AF KELLY, MA MCIVER, JK SHEA, RF HAGER, GD TI FREQUENCY TUNING OF A CW ATOMIC IODINE LASER VIA THE ZEEMAN EFFECT SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article AB The availability of a continuously operating, C3F7I photolytic 1.315-mu-m atomic iodine laser has made it possible for the first time to make precise observations of frequency tuning of an atomic iodine laser by means of the Zeeman effect. Application of a uniform magnetic field to the gain region of the photolytic iodine laser causes the laser to operate at different frequencies as a function of the strength of the applied field and the polarization of the laser. With the light polarized perpendicular to the applied magnetic field by means of Brewster output windows the laser could be tuned to frequencies near the 3-4, 2-2, and 3-3 zero-field transitions of the hyperfine spectrum of atomic iodine. With the light polarized parallel to the applied magnetic field the laser could be tuned to two frequencies bracketing the 3-4 zero-field transition and one frequency near the 2-2 transition. Measurements show close agreement between the observed frequency behavior and theoretical models. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. USAF,IODINE LASER TECH SECT,WEAPONS LAB,KIRTLAND AFB,NM 87117. RP KELLY, MA (reprint author), UNIV NEW MEXICO,DEPT PHYS & ASTRON,ALBUQUERQUE,NM 87131, USA. NR 12 TC 9 Z9 9 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD FEB PY 1991 VL 27 IS 2 BP 263 EP 273 DI 10.1109/3.78229 PG 11 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA FG745 UT WOS:A1991FG74500013 ER PT J AU LABARGA, L ADOLPHSEN, C GRATTA, G LITKE, A TURALA, M ZACCARDELLI, C BREAKSTONE, A PARKER, S BARNETT, B DAUNCEY, P DREWER, D MATTHEWS, J JACOBSEN, R LUTH, V AF LABARGA, L ADOLPHSEN, C GRATTA, G LITKE, A TURALA, M ZACCARDELLI, C BREAKSTONE, A PARKER, S BARNETT, B DAUNCEY, P DREWER, D MATTHEWS, J JACOBSEN, R LUTH, V TI THE MARK-II SILICON STRIP VERTEX DETECTOR AND PERFORMANCE OF A SILICON DETECTOR TELESCOPE IN THE MARK-II DETECTOR AT THE SLC SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article ID VLSI READOUT AB A silicon strip vertex detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). The performance of the individual modules and the stability and accuracy of their placement in the mechanical support are discussed. To gain operational experience at the SLC, a telescope made of three silicon detector modules has been assembled and placed inside the Mark II. Results from the first data run of the SLC on the overall performance of the telescope, including backgrounds, charged particle tracking, and spatial resolution, are presented. C1 UNIV HAWAII,HONOLULU,HI 96822. JOHNS HOPKINS UNIV,BALTIMORE,MD 21218. STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP LABARGA, L (reprint author), UNIV CALIF SANTA CRUZ,SANTA CRUZ INST PARTICLE PHYS,SANTA CRUZ,CA 95064, USA. NR 8 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 1991 VL 38 IS 1 BP 25 EP 29 DI 10.1109/23.64637 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA ET829 UT WOS:A1991ET82900006 ER PT J AU FIRESTONE, MA KESSEL, CE AF FIRESTONE, MA KESSEL, CE TI PLASMA KINETIC CONTROL IN A TOKAMAK SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article ID TRANSPORT AB In this work, plasma kinetic (temperature and density) control is developed in terms of optimal control theory. To do so entails solving a distributed parameter control problem for which no previous general theory or techniques could be practically implemented. Our methodology involves reducing the one-dimensional particle and energy transport partial differential equations into a system of ordinary differential equations. The latter are linearized and put into standard control theory format. This technique can be generalized to any distributed parameter system whose variables can be modeled as simple analytic functions of the spatial coordinates. It is a major result of this work. The new distributed parameter control technique shows excellent control characteristics when applied to realistic plasma temperature and density profiles. Tests were made on temperatures and densities which had been perturbed about 10% below their desired value, and profiles which were significantly more peaked than the required shape. These results were for a simplified model problem with specific empirical transport coefficients and a one species plasma. This is so far the only optimal control approach to plasma kinetic control, which has applications in burn control, stability, and energy confinement. C1 PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543. RP FIRESTONE, MA (reprint author), MISSION RES CORP,735 STATE ST,POB DRAWER 719,SANTA BARBARA,CA 93102, USA. NR 20 TC 11 Z9 11 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD FEB PY 1991 VL 19 IS 1 BP 29 EP 41 DI 10.1109/27.62364 PG 13 WC Physics, Fluids & Plasmas SC Physics GA EU276 UT WOS:A1991EU27600006 ER PT J AU FEDDEMA, JT LEE, CSG MITCHELL, OR AF FEDDEMA, JT LEE, CSG MITCHELL, OR TI WEIGHTED SELECTION OF IMAGE FEATURES FOR RESOLVED RATE VISUAL FEEDBACK-CONTROL SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article ID ROBOT AB This paper develops methodologies for the automatic selection of image features to be used to visually control the relative position and orientation (pose) between the end-effector of an eye-in-hand robot and a workpiece. A resolved motion rate control scheme is used to update the robot's pose based on the position of three features in the camera's image. The selection of these three features depends on a blend of image recognition and control criteria. The image-recognition criteria include feature robustness, completeness, cost of feature extraction, and feature uniqueness. The control criteria include system observability, controllability, and sensitivity. A weighted criteria function is used to select the combination of image features that provides the best control of the end-effector of a general six-degrees-of-freedom manipulator. Both computer simulations and laboratory experiments on a PUMA robot arm were conducted to verify the performance of the feature selection criteria. Experimentally, the PUMA robot arm with a CCD camera mounted on its end-effector was able to track a randomly moving carburetor gasket with a visual feedback cycle time of 70 ms. C1 PURDUE UNIV,SCH ELECT ENGN,W LAFAYETTE,IN 47907. UNIV TEXAS,ARLINGTON,TX 76019. RP FEDDEMA, JT (reprint author), SANDIA NATL LABS,DIV INTELLIGENT MACHINE PRINCIPLES 1411,ALBUQUERQUE,NM 87185, USA. NR 21 TC 87 Z9 87 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 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD FEB PY 1991 VL 7 IS 1 BP 31 EP 47 DI 10.1109/70.68068 PG 17 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA EV619 UT WOS:A1991EV61900004 ER PT J AU LEWIS, PS AF LEWIS, PS TI MULTICHANNEL RECURSIVE LEAST-SQUARES ADAPTIVE FILTERING WITHOUT A DESIRED SIGNAL SO IEEE TRANSACTIONS ON SIGNAL PROCESSING LA English DT Article AB Most adaptive filters require a desired signal for operation. However, in many applications the a priori knowledge consists of the signal-to-data cross-correlation matrix rather than a desired signal. Recursive sample matrix inversion (SMI) algorithms exist for this "mixed" case. These SMI algorithms, which are based on the inversion of a data correlation matrix, have both numerical and structural shortcomings. This paper demonstrates how to formulate the recursive solution to the mixed case as a least squares problem. This formulation leads to algorithms based on recursive QR decomposition, implemented by either Givens or square-root-free Givens rotations. These algorithms are efficient, numerically sound, and structurally regular. Because of their structural regularity, the algorithms are easily implemented by triangular systolic array structures as outlined in the paper. C1 UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. RP LEWIS, PS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MECH & ELECTR ENGN INSTRUMENTAT GRP MEE-3,LOS ALAMOS,NM 87545, USA. NR 17 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 1053-587X J9 IEEE T SIGNAL PROCES JI IEEE Trans. Signal Process. PD FEB PY 1991 VL 39 IS 2 BP 359 EP 365 DI 10.1109/78.80819 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA EU963 UT WOS:A1991EU96300010 ER PT J AU SRIVASTAVA, PC TEDJAMULIA, ML OWEN, BA KNAPP, FF AF SRIVASTAVA, PC TEDJAMULIA, ML OWEN, BA KNAPP, FF TI SYNTHESIS AND MYOCARDIAL SPECIFICITY OF PARA-(N-ALKYL)-[I-125]-IODOPHENYL FATTY-ACID ANALOGS SO INDIAN JOURNAL OF CHEMISTRY SECTION B-ORGANIC CHEMISTRY INCLUDING MEDICINAL CHEMISTRY LA English DT Article ID IMAGING AGENT; I-123 AB The potential usefulness of a phenyl ring in fatty acid analogues as a site for radioiodination as well as for metabolic blocking has been investigated. Model p-(n-alkyl)iodophenyl fatty acid analogues have been synthesized by thallation and iodination of the corresponding alkylphenyl substrates. The p-(n-dodecyl)benzoic acid is converted into the corresponding phenylacetic acid analogue via the corresponding benzyl alcohol, benzyl chloride and benzyl nitrile intermediates. The 4-(p-n-dodecylphenyl)butyric acid is prepared by Friedel-Crafts condensation of 1-phenyldecane with succinic anhydride followed by Clemensen reduction of the intermediate product. The radioiodinated fatty acid analogues were synthesized for tissue distribution studies in rats. The data from these studies demonstrate that the alkylphenyl fatty acid analogues show significant uptake by heart (1.5-3.5% dose/gm) and washout from the heart at a rate which correlates with the proximity of the benzene ring with the carboxylic acid group. RP SRIVASTAVA, PC (reprint author), OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,NUCL MED GRP,OAK RIDGE,TN 37831, USA. NR 27 TC 0 Z9 0 U1 0 U2 0 PU COUNCIL SCIENTIFIC INDUSTRIAL RESEARCH PI NEW DELHI PA PUBL & INFO DIRECTORATE, NEW DELHI 110012, INDIA SN 0376-4699 J9 INDIAN J CHEM B JI Indian J. Chem. Sect B-Org. Chem. Incl. Med. Chem. PD FEB PY 1991 VL 30 IS 2 BP 188 EP 194 PG 7 WC Chemistry, Organic SC Chemistry GA EV698 UT WOS:A1991EV69800015 ER PT J AU WANG, NS YANG, DL LIN, MC MELIUS, CF AF WANG, NS YANG, DL LIN, MC MELIUS, CF TI KINETICS OF CN REACTIONS WITH N2O AND CO2 SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article AB The rate constants for the reaction of CN with N2O and CO2 have been measured by the laser dissociation/laser-induced fluorescence (two-laser pump-probe) technique at temperatures between 300 and 740 K. The rate of CN + N2O was measurable above 500 K, with a least-squares averaged rate constant, k = 10(-11.8+/-0.4) exp(-3560 +/- 181/T) cm3/s. The rate of CN + CO2, however, was not measurable even at the highest temperature reached in the present work, 743 K, with [CO2] less-than-or-equal-to 1.9 x 10(18) molecules/cm3. In order to rationalize the observed kinetics, quantum mechanical calculations based on the BAC-MP4 method were performed. The results of these calculations reveal that the CN + N2O reaction takes place via stable adduct NCNNO with a small barrier of 1.1 kcal/mol. The adduct, which is more stable than the reactants by 13 kcal/mol, decomposes into the NCN + NO products with an activation energy of 20.0 kcal/mol. This latter process is thus the ratecontrolling step in the CN + N2O reaction. The CN + CO2 reaction, on the other hand, occurs with a large barrier of 27.4 kcal/mol, producing an unstable adduct NCOCO which fragments into NCO + CO with a small barrier of 4.5 kcal/mol. The large overall activation energy for this process explains the negligibly low reactivity of the CN radical toward CO2 below 1000 K. Least-squares analyses of the computed rate constants for these two CN reactions, which fit well with experimental data, give rise to k(N20) = 6.4 x 10(-21) T2.6 exp(-1860/T) cm3/s k(CO2) = 6.1 x 10(-18) T2.2 exp(-13530/T) cm3/s for the temperature range 300-3000 K. C1 EMORY UNIV,DEPT CHEM,ATLANTA,GA 30322. SANDIA NATL LABS,COMBUST RES FACIL,LIVERMORE,CA 94551. NR 11 TC 31 Z9 31 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD FEB PY 1991 VL 23 IS 2 BP 151 EP 160 DI 10.1002/kin.550230206 PG 10 WC Chemistry, Physical SC Chemistry GA EV726 UT WOS:A1991EV72600005 ER PT J AU REUTER, WG EPSTEIN, JS HAGGAG, FM AF REUTER, WG EPSTEIN, JS HAGGAG, FM TI COMPARISON BETWEEN STANDARD FRACTURE-TOUGHNESS RESULTS AND SURFACE FLAW DATA FOR SILICON-CARBIDE SO INTERNATIONAL JOURNAL OF FRACTURE LA English DT Article AB Stress intensity factors were measured for single-edge notched silicon carbide specimens subjected to three-point bending. These data are compared with experimental results from surface flawed specimens subjected to three-point bending. Surface flawed specimens were tested since they resemble defects in structures more closely than any other specimen. The ability to estimate failure conditions for a structural component using measurements of fracture toughness and appropriate equations was evaluated. In many of these tests, acoustic emission and moire interferometry techniques provided valuable information on the crack growth process, constitutive damage zone propagation, and the critical stress intensity factors. C1 GEORGIA TECH UNIV,DEPT CIVIL ENGN,ATLANTA,GA 30332. OAK RIDGE NATL LAB,OAK RIDGE,TN 37830. RP REUTER, WG (reprint author), IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 17 TC 2 Z9 2 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0376-9429 J9 INT J FRACTURE JI Int. J. Fract. PD FEB 1 PY 1991 VL 47 IS 3 BP 181 EP 200 PG 20 WC Materials Science, Multidisciplinary; Mechanics SC Materials Science; Mechanics GA EZ286 UT WOS:A1991EZ28600002 ER PT J AU DUFFEY, RB HUGHES, ED AF DUFFEY, RB HUGHES, ED TI DRYOUT STABILITY AND INCEPTION AT LOW FLOW-RATES SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID WATER AB A theoretical model for the heat flux required to maintain a stable hot patch on a heated surface cooled by a falling liquid film is developed. The theoretical model is based on an existing analytical solution of the two-dimensional heat equation with boundary conditions supplied by heat transfer coefficient correlations appropriate to the fluid conditions at the hot dry patch and at the wet region from the patch. Using physically reasonable correlation forms for the dry patch and wet region heat transfer coefficients, the heat flux is expressed as a function of the liquid film Reynolds number. Existing experimental data were compiled, collected, and used to obtain the correlating lines. The data cover the one-dimensional (low Biot number) region, and indicate that laminar and turbulent liquid film conditions occur. Corresponding correlating equations are obtained from the analytical results. For laminar flow, the dryout heat flux is q(D) = 0.27Re0.5, and for turbulent flow q(D) = 0.017Re0.9, with an uncertainty of the order of +/- 50%. RP EG&G IDAHO INC, POB 1625, IDAHO FALLS, ID 83402 USA. NR 19 TC 10 Z9 12 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 EI 1879-2189 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD FEB PY 1991 VL 34 IS 2 BP 473 EP 481 DI 10.1016/0017-9310(91)90266-H PG 9 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA EZ387 UT WOS:A1991EZ38700013 ER PT J AU GIBSON, JK AF GIBSON, JK TI MASS-SPECTRA OF N,N,N',N'-TETRAMETHYL-1,4-PHENYLENEDIAMINE USING NITROGEN LASER AND ELECTRON-IMPACT IONIZATION SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY AND ION PROCESSES LA English DT Note ID TRIPLET-STATE; N,N,N',N'-TETRAMETHYL-PARA-PHENYLENEDIAMINE; RESONANCE AB Mass spectra are reported for N,N,N',N'-tetramethyl-1,4-phenylenediamine (TMPD). Both electron impact ionization (19 eV and 50 eV electrons) and nitrogen laser photoionization (lambda = 337 nm) were utilized, and the respective spectra are discussed and compared. In addition, a particularly curious ionization behavior observed under conditions of concurrent laser illumination and electron impact is described; it is proposed that these observations may reflect a cooperative process of electron impact ionization of photoexcited TMPD. RP GIBSON, JK (reprint author), OAK RIDGE NATL LAB,DIV CHEM,POB 2008,OAK RIDGE,TN 37831, USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1176 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. Ion Process. PD FEB 1 PY 1991 VL 104 IS 2 BP R1 EP R10 DI 10.1016/0168-1176(91)80007-A PG 10 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA EZ342 UT WOS:A1991EZ34200007 ER PT J AU BIELSKI, BHJ CABELLI, DE AF BIELSKI, BHJ CABELLI, DE TI HIGHLIGHTS OF CURRENT RESEARCH INVOLVING SUPEROXIDE AND PERHYDROXYL RADICALS IN AQUEOUS-SOLUTIONS SO INTERNATIONAL JOURNAL OF RADIATION BIOLOGY LA English DT Article ID WATER-SOLUBLE PORPHYRINS; PULSE RADIOLYTIC INVESTIGATIONS; ELECTRON-SPIN-RESONANCE; CHEMICAL-PROPERTIES; DISMUTASE ACTIVITY; HYDROGEN-PEROXIDE; HO2/O2 RADICALS; RATE-CONSTANT; MANGANESE(II) COMPLEXES; OZONE DECOMPOSITION AB Selected topics of current research on HO2/O-2 radical reactions in aqueous solutions are described. The subject is introduced by a brief review of the fundamental background chemistry of HO2/O-2, including a description of the rates and mechanisms of formation and decay as well as their spectral properties, current research on self-exchange rates, etc. This is followed by examples of their reactivity with simple metal complexes of iron, manganese and copper and extended to some biological significant metal-containing systems such as porphyrins, haem enzymes and superoxide dismutases. Some recent results on the interaction of these oxy-radicals with antioxidants, specifically vitamin C and E, are discussed. A brief review of some topical chemistry describing HO2/O-2 involvement in atmospheric and aquatic chemistry is given. Finally, some new trends in the areas of heterogeneous catalysis and reactor chemistry that involve these species are described. RP BIELSKI, BHJ (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 133 TC 91 Z9 94 U1 2 U2 13 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0955-3002 J9 INT J RADIAT BIOL JI Int. J. Radiat. Biol. PD FEB PY 1991 VL 59 IS 2 BP 291 EP 319 DI 10.1080/09553009114550301 PG 29 WC Biology; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA EZ398 UT WOS:A1991EZ39800003 PM 1671684 ER PT J AU ZHANG, SY AF ZHANG, SY TI INFINITE GAIN LOOP AND SIMULATION OF SINGULAR SYSTEMS SO INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE LA English DT Article ID GENERALIZED STATE-SPACE; POLE PLACEMENT; DECOUPLING ZEROS; RATIONAL MATRIX; FORM; CONTROLLABILITY; OBSERVABILITY AB We present a simulation for singular systems. An infinite gain loop is discussed and used to generate an impulsive mode for both single-input-output and multivariable systems, then the simulation is implemented by integrators and amplifiers. Some interesting issues such as the reachability at infinity, the controllability at infinity and the impulsive mode elimination are scrutinized by using the simulation. RP ZHANG, SY (reprint author), BROOKHAVEN NATL LAB,AGS DEPT,UPTON,NY 11973, USA. NR 21 TC 0 Z9 1 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNDPOWDER SQUARE, LONDON, ENGLAND EC4A 3DE SN 0020-7721 J9 INT J SYST SCI JI Int. J. Syst. Sci. PD FEB PY 1991 VL 22 IS 2 BP 433 EP 441 DI 10.1080/00207729108910622 PG 9 WC Automation & Control Systems; Computer Science, Theory & Methods; Operations Research & Management Science SC Automation & Control Systems; Computer Science; Operations Research & Management Science GA EV628 UT WOS:A1991EV62800016 ER PT J AU LOVEJOY, ML KEYES, BM KLAUSMEIERBROWN, ME MELLOCH, MR AHRENKIEL, RK LUNDSTROM, MS AF LOVEJOY, ML KEYES, BM KLAUSMEIERBROWN, ME MELLOCH, MR AHRENKIEL, RK LUNDSTROM, MS TI ZERO-FIELD TIME-OF-FLIGHT MEASUREMENTS OF ELECTRON-DIFFUSION IN P+-GAAS SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Article DE P+-GAAS; ZERO FIELD; MINORITY CARRIER DIFFUSION; RADIATIVE LIFETIME; SURFACE RECOMBINATION VELOCITY; TRANSIENT VOLTAGE RESPONSE; STEADY-STATE QUANTUM EFFICIENCY ID MINORITY-CARRIER TRANSPORT; MOBILITY AB Minority electron diffusivities in p+ -GaAs-doped N(A) congruent-to 1.4 x 10(18) and approximately 10(19) cm-3 have been measured in zero-field conditions with an extension of the zero-field time-of-flight technique. Extension of the technique to make it applicable to heavily doped p+ -GaAs is described and zero-field data are discussed. Unexpectedly, majority carrier drag effects are not evident in a comparison of this data with recently reported high-field data. Low zero-field mobility of electrons in p+ - GaAs has important implications for high-speed devices such as heterojunction bipolar transistors. C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. VARIAN RES CTR,PALO ALTO,CA. RP LOVEJOY, ML (reprint author), PURDUE UNIV,W LAFAYETTE,IN 47907, USA. NR 9 TC 11 Z9 11 U1 0 U2 1 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD FEB 1 PY 1991 VL 30 IS 2A BP L135 EP L137 DI 10.1143/JJAP.30.L135 PG 3 WC Physics, Applied SC Physics GA EW572 UT WOS:A1991EW57200001 ER PT J AU MORE, RM AF MORE, RM TI SEMICLASSICAL MATRIX-MECHANICS .2. ANGULAR-MOMENTUM OPERATORS SO JOURNAL DE PHYSIQUE II LA English DT Article AB Semiclassical angular momentum matrices are calculated using a new contour-integral formula for matrix-elements. WKB spherical harmonic functions are found to be exactly orthonormal with the contour-integral inner-product. Matrix-elements obtained from these wave-functions are accurate to about 2% and the matrices obey the commutation relations expected of quantum angular momentum operators. The semiclassical wave-functions are related to a superposition of allowed classical orbits and this illustrates the connection to the Feynman path-summation formulation of quantum mechanics for electrons in a spherically symmetric potential. RP MORE, RM (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, L-321, LIVERMORE, CA 94550 USA. NR 26 TC 1 Z9 1 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1155-4312 J9 J PHYS II JI J. Phys. II PD FEB PY 1991 VL 1 IS 2 BP 97 EP 121 PG 25 WC Mechanics; Physics, Atomic, Molecular & Chemical SC Mechanics; Physics GA EX199 UT WOS:A1991EX19900003 ER PT J AU PRELL, LJ STYRIS, DL REDFIELD, DA AF PRELL, LJ STYRIS, DL REDFIELD, DA TI COMPARISON OF ATOMIZATION MECHANISMS FOR GROUP IIA ELEMENTS IN ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article DE ATOMIZATION MECHANISMS; ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY; MASS SPECTROMETRY; GROUP IIA ELEMENTS ID GRAPHITE-FURNACE ATOMIZATION; TUBE; SPECTROSCOPY; EMISSION; SURFACE; BARIUM AB Atomic absorption and mass spectrometry were used simultaneously to elucidate mechanisms responsible for atomization of Group IIA elements (beryllium, magnesium, calcium, strontium and barium) in pyrolytic graphite furnaces. Gaseous species of these elements, deposited as the nitrates and vaporized in 1 atm of nitrogen and in vacuum, were analysed in real-time by mass spectrometric sampling. The principal gas phase analyte species observed were carbides, oxides and hydroxides. Excluding beryllium, the data suggest that Group IIA atomization and carbide formation begin with the dissociative adsorption of the oxides are formed as a result of associative adsorption and the hydroxides are formed by homogeneous gas phase reactions of the carbides and oxides with adsorption and the hydroxides are formed by homogeneous gas phase reactions of the carbides and oxides with water vapour. C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. NW NAZARENE COLL, NAMPA, ID 83651 USA. NR 47 TC 41 Z9 41 U1 4 U2 6 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK MILTON ROAD, CAMBRIDGE, CAMBS, ENGLAND CB4 4WF SN 0267-9477 J9 J ANAL ATOM SPECTROM JI J. Anal. At. Spectrom. PD FEB PY 1991 VL 6 IS 1 BP 25 EP 32 DI 10.1039/ja9910600025 PG 8 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA FB807 UT WOS:A1991FB80700004 ER PT J AU EVANS, JW SAVASKAN, G AF EVANS, JW SAVASKAN, G TI A ZINC AIR CELL EMPLOYING A PACKED-BED ANODE SO JOURNAL OF APPLIED ELECTROCHEMISTRY LA English DT Article ID BATTERIES; SYSTEMS; BEHAVIOR AB A cell with a particulate zinc electrode and a monofunctional air electrode has been studied on a laboratory scale. The cell has the feature of relying on solutal natural convection, rather than a pump, for electrolyte circulation. Cells of 80 and 400 cm2 (air electrode area) have been discharged at constant or stepped current. In two cases cell discharge was halted and restarted after many hours with little or no impact on cell voltage. Based on the laboratory data a preliminary design of a 32 k Wh (115 MJ) battery was completed. The projected specific energy of this cell is 79.2 Wh kg-1 (637 kJkg-1), while the peak specific power is 111 W kg-1 (20% depth of discharge), meeting of the US Department of Energy targets for a battery for an electric van. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. RP EVANS, JW (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 17 TC 15 Z9 16 U1 9 U2 15 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0021-891X J9 J APPL ELECTROCHEM JI J. Appl. Electrochem. PD FEB PY 1991 VL 21 IS 2 BP 105 EP 110 DI 10.1007/BF01464289 PG 6 WC Electrochemistry SC Electrochemistry GA EV245 UT WOS:A1991EV24500003 ER PT J AU PORCH, WM CLEMENTS, WE COULTER, RL AF PORCH, WM CLEMENTS, WE COULTER, RL TI NIGHTTIME VALLEY WAVES SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DEEP VALLEY; TRIBUTARY; VELOCITY; WIND AB This paper describes a regular oscillation observed in nighttime drainage airflow in a valley under relatively light upper-level wind conditions. The period of these oscillations is about 20 minutes with at least one harmonic at about 10 minutes. A strong coherence between tributary flow and main valley fluctuations was observed, with the phase of the tributary flow leading the valley oscillation; this indicates the importance of tributaries as major contributors to the dynamics of cold air flow in valleys. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP PORCH, WM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,EES 590-390,MS F665,LOS ALAMOS,NM 87545, USA. NR 16 TC 12 Z9 13 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 1991 VL 30 IS 2 BP 145 EP 156 DI 10.1175/1520-0450(1991)030<0145:NVW>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FB832 UT WOS:A1991FB83200001 ER PT J AU COULTER, RL MARTIN, TJ PORCH, WM AF COULTER, RL MARTIN, TJ PORCH, WM TI A COMPARISON OF NOCTURNAL DRAINAGE FLOW IN 3 TRIBUTARIES SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DEEP VALLEY AB The characteristics of tributary drainage flow in stable, nocturnal conditions in three closely located tributaries are compared. The orientation of the tributaries with respect to Kimball Creek, into which they drain, appears to be a controlling factor in the tributary flow. In particular, oscillations in the drainage flow are found to be weakest and drainage mass per unit area greatest in the tributary most closely aligned with the main canyon. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. RP COULTER, RL (reprint author), ARGONNE NATL LAB,DIV ENVIRONM RES,BEM,CER 203,9700 S CASS,ARGONNE,IL 60439, USA. NR 9 TC 6 Z9 6 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD FEB PY 1991 VL 30 IS 2 BP 157 EP 169 DI 10.1175/1520-0450(1991)030<0157:ACONDF>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA FB832 UT WOS:A1991FB83200002 ER PT J AU KELSON, I NIR, D ZIDON, A DUMONT, H PERRAILLON, B HAUSTEIN, P AF KELSON, I NIR, D ZIDON, A DUMONT, H PERRAILLON, B HAUSTEIN, P TI ULTRACLEAN RADIOISOTOPE MARKING BY NUCLEAR STIMULATED DESORPTION SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DELAYED DESORPTION AB A method for ultraclean radioactive marking is presented, utilizing the process of nuclear stimulated desorption. It employs a sequence of two slow radioactive decays. The primary decay causes a nucleus to desorb from a substrate onto which it had been placed. The desorbing daughter nuclei, being themselves radioactive, then constitute an ultraclean marking flux. A manifestation of this mechanism for the special case of the Ca-47 --> Sc-47 --> Ti-47 decay is described. An application to end-point detection in wet etching is presented and quantitatively simulated. C1 CENS,F-91191 GIF SUR YVETTE,FRANCE. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP KELSON, I (reprint author), TEL AVIV UNIV,RAYMOND & BEVERLY SACKLER FAC EXACT SCI,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1147 EP 1150 DI 10.1063/1.347295 PG 4 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100003 ER PT J AU SUTTON, SB ALBRECHT, GF AF SUTTON, SB ALBRECHT, GF TI OPTIMUM PERFORMANCE CONSIDERATIONS FOR A LARGE-APERTURE AVERAGE POWER SOLID-STATE LASER-AMPLIFIER SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB The effect of a gas cooling system on the efficiency of an average-power solid-state disk laser amplifier is addressed. Such a configuration has application in solid-state fusion drivers. Analytical models are discussed that identify the important parameters in specifying an optimized laser and optimized cooling system. It is shown that the penalty that the cooling and conditioning system power requirements have on the overall laser system efficiency can be easily maintained below 10%, particularly for large-aperture systems. RP SUTTON, SB (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,L-495,POB 808,LIVERMORE,CA 94550, USA. NR 10 TC 14 Z9 14 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1183 EP 1191 DI 10.1063/1.347302 PG 9 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100010 ER PT J AU JENCIC, I BENCH, MW ROBERTSON, IM KIRK, MA AF JENCIC, I BENCH, MW ROBERTSON, IM KIRK, MA TI A COMPARISON OF THE AMORPHIZATION INDUCED IN ALXGA1-XAS AND GAAS BY HEAVY-ION IRRADIATION SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID IMPLANTED GAAS; COLLISION CASCADES; SUPERLATTICES; ALAS; DIFFUSION; LASERS; SI; INTERDIFFUSION; CONFINEMENT; BOMBARDMENT AB The response of Al(x)Ga(1-x)As/GaAs samples to bombardment with heavy ions (50 keV Kr+, 50 keV and 1.5 MeV Xe+) was studied as a function of ion dose at temperatures of 30 and 300 K using transmission electron microscopy. Samples with x = 0.2 and 0.85 were used. Under all irradiation temperature and ion combinations, the AlGaAs was more resistant to amorphization than GaAs. The resistance increased with increasing Al content and decreased with decreasing irradiation temperature. This difference in the response may be attributed to differences either in the mechanisms by which a region is rendered amorphous (i.e., by direct impact amorphization or by the buildup of point defects) or to differences in the inherent stability (recrystallization temperature and rate) of individual amorphous zones in AlGaAs and GaAs. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. JOZEF STEFAN INST,YU-6111 LJUBLJANA,YUGOSLAVIA. RP JENCIC, I (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801, USA. NR 47 TC 34 Z9 34 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1287 EP 1293 PG 7 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100024 ER PT J AU ROSSI, F NASTASI, M AF ROSSI, F NASTASI, M TI CASCADE STRUCTURE AND OVERLAP EFFECTS IN ION-BEAM MIXING EXPERIMENTS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ENERGETIC DISPLACEMENT CASCADES; MOLECULAR-DYNAMICS; THERMAL SPIKES; TEMPERATURE AB General considerations about ion-beam mixing are reviewed: we show that the cascade structure, i.e., the distribution of spikes in the cascade volume, can have a strong influence on the ion-beam mixing efficiency. We first give an analytical expression of mixing rate versus the thermodynamic parameters and the spike distribution function in the case where the spikes are distributed randomly in the cascade and no overlap is taken into account. When several spikes occur in the same volume at the same time, it is shown that the temperature field is modified, and the jump frequency and diffusion rate change. This problem cannot be solved analytically, and we introduce a basic Monte Carlo calculation, where diffusion in the spikes in the case of overlap is treated. This calculation allows us to describe what happens when the substrate temperature is increased: starting from the hypothesis that the spike volume increases with temperature following an Arrhenius law, we find expressions for the activation energy in the thermally activated regime and the values of onset temperatures for thermally assisted diffusion under irradiation. The values found are in good agreement with experimental results published in the literature. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. OI Rossi, Francois/0000-0003-3090-1398 NR 21 TC 22 Z9 22 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1310 EP 1319 DI 10.1063/1.347266 PG 10 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100028 ER PT J AU HANAK, TR AHRENKIEL, RK TIMMONS, ML AF HANAK, TR AHRENKIEL, RK TIMMONS, ML TI CAPTURE BARRIER AND THE IONIZATION ENTROPY OF THE DX CENTER IN SE-DOPED ALXGA1-XAS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PERSISTENT PHOTOCONDUCTIVITY; ENERGY-LEVEL; SEMICONDUCTORS; ALLOYS; MODEL; GAAS AB Recently there has been clear evidence that local alloy disorder splits the DX center in multiple levels. This effect is observed by deep-level transient spectroscopy (DLTS) from different thermal emission rates for the multiple levels in Al(x)Ga(1-x)As We report for the first time the simultaneous measurement of two capture barrier and two ionization entropies for the DX center in Se-doped Al(x)Ga(1-x)As. The Al(x)Ga(1-x)As was grown by metalorganic chemical vapor deposition at two different alloy compositions (x = 0.19 and 0.23). We obtained the capture rates from a DLTS experiment by simultaneously monitoring the two transient signals while changing the filling pulse width. The capture rates show exponential temperature dependence from which the thermal capture barriers are extracted. Together with the emission rate values the ionization entropy is calculated after modifying the appropropriate equations for a degenerate semiconductor (N(D) > 1 x 10(17) for AlGaAs). The results are discussed in the context of other published values. C1 UNIV DENVER,DEPT PHYS,DENVER,CO 80210. SOLAR ENERGY RES INST,GOLDEN,CO 80401. RES TRIANGLE INST,RES TRIANGLE PK,NC 27709. NR 23 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1425 EP 1428 DI 10.1063/1.347282 PG 4 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100044 ER PT J AU ESTLER, RC NOGAR, NS AF ESTLER, RC NOGAR, NS TI ABLATION OF HIGH-TEMPERATURE SUPERCONDUCTOR STUDIED BY RESONANCE IONIZATION MASS-SPECTROMETRY (RIMS) SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SECONDARY-ION SPECTRA; LASER ABLATION; THIN-FILMS; CU; SPECTROSCOPY; DEPOSITION; EMISSION; FLUORESCENCE; VAPORIZATION; EVAPORATION AB Laser ablation of bulk high-temperature superconductor (HTS) material provides a useful means of producing high quality HTS thin films. Mass spectrometric probes of the ablation plume provide a microscopic understanding of the ablation event and plume development as well as providing a process monitor for the thin-film production. Resonance ionization mass spectrometry (RIMS) detection of the ablated neutral species supplies valuable physical information about the ablation event necessary for developing models of the process. Time-of-flight/RIMS detection of Cu, Y, and BaO ablated from YBa2Cu3O7-x indicates the ablation involves post-desorption gas phase collisions, which influence the ablation chemistry and dynamics (e.g., angular and velocity distributions). Approximately equal velocities are observed for all neutral species at constant ablation laser fluence. In addition, BaO exhibits a rotational temperature far less than the directed translational temperature. C1 FT LEWIS COLL,DEPT CHEM,DURANGO,CO 81301. RP ESTLER, RC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV CHEM & LASER SCI,MS G 738,LOS ALAMOS,NM 87545, USA. NR 31 TC 33 Z9 33 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 1991 VL 69 IS 3 BP 1654 EP 1659 DI 10.1063/1.347209 PG 6 WC Physics, Applied SC Physics GA EW671 UT WOS:A1991EW67100081 ER PT J AU SOUMPASIS, DM TUNG, CS GARCIA, AE AF SOUMPASIS, DM TUNG, CS GARCIA, AE TI RIGOROUS DESCRIPTION OF DNA STRUCTURES .2. ON THE COMPUTATION OF BEST AXES, PLANES, AND HELICES FROM ATOMIC COORDINATES SO JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS LA English DT Article ID B-DNA; BASE SEQUENCE; A-DNA; PARAMETERS; DODECAMER AB We show that diagonalization of the moments of inertia tensor of an arbitrary molecular structure automatically yields the best (least squares) points, line, and plane through the structure. Furthermore, we show how to compute best helices using atomic coordinates. These results supplement the general methodology for description of DNA structures proposed recently (D.M. Soumpasis and C.-S. Tung, J. Biomol. Struct. Dyn. 6, 397-420, 1988). C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP SOUMPASIS, DM (reprint author), MAX PLANCK INST BIOPHYS CHEM,DEPT MOLEC BIOL,POB 2841,W-3400 GOTTINGEN,GERMANY. FU NIGMS NIH HHS [GM-7812] NR 18 TC 16 Z9 16 U1 0 U2 1 PU ADENINE PRESS INC PI GUILDERLAND PA PO BOX 355/340, GUILDERLAND, NY 12084 SN 0739-1102 J9 J BIOMOL STRUCT DYN JI J. Biomol. Struct. Dyn. PD FEB PY 1991 VL 8 IS 4 BP 867 EP 888 PG 22 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA FB460 UT WOS:A1991FB46000010 PM 2059344 ER PT J AU HERZENBERG, CL MESCHEL, SV ALTENA, JA AF HERZENBERG, CL MESCHEL, SV ALTENA, JA TI WOMEN SCIENTISTS AND PHYSICIANS OF ANTIQUITY AND THE MIDDLE-AGES SO JOURNAL OF CHEMICAL EDUCATION LA English DT Article C1 UNIV CHICAGO,CHICAGO,IL 60637. RP HERZENBERG, CL (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 28 TC 2 Z9 2 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0021-9584 J9 J CHEM EDUC JI J. Chem. Educ. PD FEB PY 1991 VL 68 IS 2 BP 101 EP 105 PG 5 WC Chemistry, Multidisciplinary; Education, Scientific Disciplines SC Chemistry; Education & Educational Research GA EY746 UT WOS:A1991EY74600008 ER PT J AU BARKENBUS, BD ZYGMUNT, BC DOBSON, JE AF BARKENBUS, BD ZYGMUNT, BC DOBSON, JE TI HMIMS - HAZARDOUS MATERIALS INCIDENT MANAGEMENT-SYSTEM FOR AIR-FORCE FIRE DEPARTMENTS SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Article AB The Hazardous Materials Incident Management System (HMIMS), an integral part of the Air Force comprehensive hazardous material (HAZMAT) program, is a computerized chemical incident response system. It is intended primarily for use by Air Force fire departments to retrieve response information during chemical incidents and as an instrument to collect information on amount, location, and nature of chemicals on the base. Both graphic and nongraphic data are supported by the HMIMS. The graphics include a hierarchy of maps which supports both small-scale (as a regional map) and large-scale (building or room) display. The nongraphics databases incorporate the chemical inventories, Material Safety Data Sheets, Response Data Sheets, and standard operating procedures, and the site characterization and analysis information necessary to generate Superfund Amendments and Reauthorization Title III Tier I and Tier II reports. The HMIMS is installed on two personal computers, one at the fire house and another on a HAZMAT vehicle at the incident site. Communications software enables the two to act in conjunction. The HMIMS assists hazard assessment and response during HAZMAT emergencies, provides incident management guidelines, and functions as a training tool to simulate emergency response. RP BARKENBUS, BD (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD FEB PY 1991 VL 31 IS 1 BP 137 EP 143 DI 10.1021/ci00001a025 PG 7 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA EZ409 UT WOS:A1991EZ40900026 ER PT J AU PARKS, EK WINTER, BJ KLOTS, TD RILEY, SJ AF PARKS, EK WINTER, BJ KLOTS, TD RILEY, SJ TI THE STRUCTURE OF NICKEL CLUSTERS SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC SHELL STRUCTURE; IRON CLUSTERS; METAL-CLUSTERS; ICOSAHEDRAL STRUCTURE; MICROCLUSTERS; PARTICLES; HYDROGEN; AMMONIA; GE; CHEMISORPTION AB The reactions of nickel clusters with ammonia and with water are used to probe cluster geometrical structure. Ammonia uptake experiments allow the determination of the number of preferred binding sites on cluster surfaces. This number shows pronounced minima in the 50- to 116-atom size range for many of the cluster sizes that appear as magic numbers in mass spectra of rare gas clusters. Since these magic numbers arise from closings of shells and subshells of the Mackay icosahedra, the correlation suggests that ammoniated nickel clusters in this size region also have icosahedral structure. Similar structure is found for ammoniated clusters smaller than approximately 30 atoms, but is not seen for room temperature clusters in the vicinity of the third shell closing at 147 atoms. Icosahedral features do appear for the larger clusters at elevated temperatures. For many clusters above 50 atoms, prolonged exposure to ammonia causes a conversion from the icosahedral structure to some other structure that binds more ammonia molecules, and often the two structures are seen together. The equilibrium reaction of a single water molecule with the bare clusters probes the strength of the cluster-water bond. Enhanced water adsorption is often seen for clusters one atom larger than those showing minima in ammonia uptake, suggesting that these bare clusters likewise have icosahedral structure. The reasons for minima in ammonia uptake and maxima in water binding are discussed. RP PARKS, EK (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Winter, Bernd/D-4657-2011 NR 51 TC 166 Z9 170 U1 2 U2 19 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 1 PY 1991 VL 94 IS 3 BP 1882 EP 1902 DI 10.1063/1.459910 PG 21 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600026 ER PT J AU KIM, SK CHOI, YS PIBEL, CD ZHENG, QK MOORE, CB AF KIM, SK CHOI, YS PIBEL, CD ZHENG, QK MOORE, CB TI DETERMINATION OF THE SINGLET TRIPLET BRANCHING RATIO IN THE PHOTODISSOCIATION OF KETENE SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PRODUCT STATE DISTRIBUTIONS; LASER-INDUCED FLUORESCENCE; ADIABATIC CHANNEL MODEL; TRANSITION-STATES; UNIMOLECULAR PROCESSES; PHOTOFRAGMENTATION DYNAMICS; RATE CONSTANTS; DISSOCIATIONS; LOOSENESS; THRESHOLD AB The rotational distributions of CO products from the dissociation of ketene at photolysis energies 10 cm-1 below, 56, 110, 200, 325, 425, 1107, 1435, 1720, and 2500 cm-1 above the singlet threshold (30 116.2 cm-1), are measured in a supersonic free jet of ketene. The CO(upsilon" = 0) rotational distributions at 56, 110, 200, 325, and 425 cm-1 are bimodal. The peaks at low J's which are due to CO from the singlet channel, show that the product rotational distribution of CO product from ketene dissociation on the singlet surface is well described kby phase space theory (PST). For CO(upsilon" = 0) rotational distributions at higher excess energies (1107, 1435, 1720, and 2500 cm-1), the singlet and triplet contributions are not clearly resolved, and the singlet/triplet branching ratios are estimated by assuming that PST accurately predicts the CO rotational distribution from the singlet channel and that the distribution from the triplet channel changes little from that at 10 cm-1 below the singlet threshold. The singlet yield shows a rapid increase in the low excess energy region (0-300 cm-1), and a slower increase above. The singlet and triplet rate constants are derived from the directly measured total rate constants using the singlet yields. The triplet rate constant increases monotonically with increasing photolysis energy through the singlet threshold region. The singlet rate constant is accurately established in the threshold region and found to increase much less rapidly than predicted by phase space theory. At 2500 cm-1 excess energy, the CO(upsilon" = 1) rotational distribution is obtained, and the ratio of CO(upsilon" = 1) to CO(upsilon" = 0) products for the singlet channel is measured to be 0.045 +/- 0.017. This ratio is close to the vibrational Rice-Ramsberger-Kassel-Marcus (RRKM) calculation 0.038, and the separate statistical ensembles (SSE) prediction 0.041, but much greater than the PST prediction, 0.016. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CHEM SCI,BERKELEY,CA 94720. RP KIM, SK (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. RI Kim, Sang Kyu/C-1613-2011 NR 27 TC 53 Z9 53 U1 1 U2 5 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 1 PY 1991 VL 94 IS 3 BP 1954 EP 1960 DI 10.1063/1.459917 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600034 ER PT J AU ITOH, K HOLROYD, R NISHIKAWA, M AF ITOH, K HOLROYD, R NISHIKAWA, M TI THE HALL-MOBILITY OF EXCESS ELECTRONS IN NORMAL-PENTANE NEOPENTANE MIXTURES SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID QUASI-FREE-ELECTRON; LIQUID-HYDROCARBON MIXTURES; ENERGY V0; TEMPERATURE; TRANSPORT; DENSITY; METHANE; KRYPTON; ARGON; XENON AB Measurements of the Hall and drift mobilities are reported for mixtures of n-pentane and neopentane up to 30% n-pentane and for the temperature range 20-150-degrees-C. Under these conditions the Hall mobility is approximately equal to the drift mobility. The results suggest that the electron remains quasifree. Changes in the mobility are attributed to enhanced scattering of quasifree electrons. C1 UNIV TOKYO,DEPT PURE & APPL SCI,MEGURO KU,TOKYO 153,JAPAN. RP ITOH, K (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 25 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1991 VL 94 IS 3 BP 2073 EP 2076 DI 10.1063/1.459930 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600047 ER PT J AU NELLIS, WJ RADOUSKY, HB HAMILTON, DC MITCHELL, AC HOLMES, NC CHRISTIANSON, KB VANTHIEL, M AF NELLIS, WJ RADOUSKY, HB HAMILTON, DC MITCHELL, AC HOLMES, NC CHRISTIANSON, KB VANTHIEL, M TI EQUATION-OF-STATE, SHOCK-TEMPERATURE, AND ELECTRICAL-CONDUCTIVITY DATA OF DENSE FLUID NITROGEN IN THE REGION OF THE DISSOCIATIVE PHASE-TRANSITION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COMPRESSED LIQUID-NITROGEN; RAMAN-SPECTROSCOPY; MOLECULAR FLUIDS; SOLID NITROGEN; HIGH-DENSITIES; 900 KBAR; 1 MBAR; GPA; PRESSURES; THERMODYNAMICS AB The dissociative phase transition of fluid nitrogen at pressures in the range 30-110 GPa (0.3-1.1 Mbar), temperatures in the range 4000-14000 K, densities up to 3.5 g/cm3, and internal energies up to 1 MJ/mol was investigated by shock compression. Equation-of-state, shock-temperature, and electrical-conductivity experimental data are presented and analyzed in detail. RP NELLIS, WJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 55 TC 88 Z9 93 U1 1 U2 7 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 1 PY 1991 VL 94 IS 3 BP 2244 EP 2257 DI 10.1063/1.459895 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600066 ER PT J AU XIAO, XD VOGEL, V SHEN, YR MAROWSKY, G AF XIAO, XD VOGEL, V SHEN, YR MAROWSKY, G TI MOLECULAR MONOLAYERS OF CHARGE-TRANSFER COMPLEXES - PROTONATION AND AGGREGATION STUDIED BY 2ND HARMONIC-GENERATION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LINEAR OPTICAL-PROPERTIES; LANGMUIR-BLODGETT FILMS; 2ND-HARMONIC GENERATION; ORGANIC-MOLECULES; HEMICYANINE DYE; BEHENIC ACID; DERIVATIVES AB Second-order optical nonlinearities of molecules can be strongly affected by the environment. Protonation and aggregation of the dyes 4-amino-4'-nitrostilbene (NS) and hemicyanine (HC), are investigated by second harmonic generation from molecular monolayers floating on water. The observed second-order nonlinearity of such molecules in the form of either a pure monolayer or a monolayer diluted with stearic acid directly reflects the degree of protonation of the molecules. For NS and HC, the variation of the second-order molecular polarizability with protonation is opposite. It is demonstrated that the measured nonlinearity can be used to deduce the effective proton concentration in the surface region. The proton concentration close to a steric acid monolayer floating on water, for example, is found to be approximately 7 orders of magnitude larger than the bulk proton concentration when the latter is low. The effects of stearic acid in diluting a dye molecular monolayer on changing the environment and breaking dye aggregates are discussed. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. MAX PLANCK INST BIOPHYS CHEM,W-3400 GOTTINGEN,GERMANY. RP XIAO, XD (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720, USA. RI Vogel, Viola/O-8025-2015 OI Vogel, Viola/0000-0003-2898-7671 NR 27 TC 29 Z9 29 U1 0 U2 2 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 1 PY 1991 VL 94 IS 3 BP 2315 EP 2323 DI 10.1063/1.459903 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600074 ER PT J AU FLESCH, GD NG, CY AF FLESCH, GD NG, CY TI ABSOLUTE TOTAL CROSS-SECTIONS FOR THE CHARGE-TRANSFER AND DISSOCIATIVE CHARGE-TRANSFER CHANNELS IN THE COLLISIONS OF O+(4S)+H2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID POTENTIAL-ENERGY SURFACE; ION-MOLECULE REACTION; ISOTOPIC VARIANTS D2; RELATIVE ENERGIES; EXCITED-STATES; GASEOUS IONS; H2O+ ION; + H; DYNAMICS; SCATTERING C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP FLESCH, GD (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 34 TC 23 Z9 23 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 1 PY 1991 VL 94 IS 3 BP 2372 EP 2373 DI 10.1063/1.459859 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600082 ER PT J AU KOLLIA, Z ZAFIROPULOS, V FOTAKIS, C STOCKDALE, JAD AF KOLLIA, Z ZAFIROPULOS, V FOTAKIS, C STOCKDALE, JAD TI LASER-INDUCED CLUSTERING IN THIOPHENOL SO JOURNAL OF CHEMICAL PHYSICS LA English DT Note ID ENHANCED ELECTRON-ATTACHMENT; PARTICLES; LIGHT; VAPOR C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP KOLLIA, Z (reprint author), HELLAS INST ELECTR STRUCT & LASER,FDN RES & TECHNOL,POB 1527,GR-71110 HERAKLION,GREECE. RI Fotakis, Costas/G-8751-2011 NR 14 TC 1 Z9 1 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 1 PY 1991 VL 94 IS 3 BP 2374 EP 2375 DI 10.1063/1.459860 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EV576 UT WOS:A1991EV57600083 ER PT J AU RUBIN, EM WITKOWSKA, HE SPANGLER, E CURTIN, P LUBIN, BH MOHANDAS, N CLIFT, SM AF RUBIN, EM WITKOWSKA, HE SPANGLER, E CURTIN, P LUBIN, BH MOHANDAS, N CLIFT, SM TI HYPOXIA-INDUCED INVIVO SICKLING OF TRANSGENIC MOUSE RED-CELLS SO JOURNAL OF CLINICAL INVESTIGATION LA English DT Article DE HEMOGLOBIN-S ANTILLES; ANIMAL MODEL; SICKLE CELL ANEMIA; HEMOGLOBIN POLYMERIZATION ID BETA-GLOBIN GENE; MASS-SPECTROMETRY; HUMAN-HEMOGLOBIN; MICE; EXPRESSION; HYBRIDIZATION; THALASSEMIA; VECTORS; CHAINS; DNA AB To develop an animal model for sickle cell anemia, we have created transgenic mice that express a severe naturally occurring human sickling hemoglobin, HB S Antilles. Due to its low solubility and oxygen affinity, Hb S Antilles have a greater propensity to cause red cell sickling than Hb S. To make transgenic animals that express a high level of Hb S Antilles, the erythroid-specific DNAse I hypersensitive site II from the human-beta-globin cluster was linked independently to the human-alpha-2-globin gene and to the beta-S Antilles gene. Embryos were injected with both constructs simultaneously and seven transgenic mice were obtained, three of which contained both the human-alpha and the human-beta S Antilles transgene. After crossing the human transgenes into the mouse-beta-thalassemic background a transgenic mouse line was derived in which approximately half the beta-globin chains in the murine red cells were human-beta-S Antilles. Deoxygenation of the transgenic red cells in vitro resulted in extensive sickling. An increase of in vivo sickling was achieved by placing these transgenic mice in a low sickling was achieved by placing these transgenic mice in a low oxygen environment. This murine model for red cell sickling should help to advance our understanding of sickle cell disease and may provide a model to test therapeutic interventions. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV RES MED,BERKELEY,CA 94720. UNIV CALIF SAN FRANCISCO,DEPT MED,SAN FRANCISCO,CA 94143. CHILDRENS HOSP,OAKLAND RES INST,OAKLAND,CA 94609. RP RUBIN, EM (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV CELL & MOLEC BIOL,1 CYCLOTRON RD,74-157,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL-31579, HL-20985-12]; PHS HHS [R0-121061] NR 32 TC 45 Z9 45 U1 0 U2 0 PU ROCKEFELLER UNIV PRESS PI NEW YORK PA 222 E 70TH STREET, NEW YORK, NY 10021 SN 0021-9738 J9 J CLIN INVEST JI J. Clin. Invest. PD FEB PY 1991 VL 87 IS 2 BP 639 EP 647 DI 10.1172/JCI115041 PG 9 WC Medicine, Research & Experimental SC Research & Experimental Medicine GA EW295 UT WOS:A1991EW29500035 PM 1991848 ER PT J AU HOGLUND, DE AZIZ, MJ STIFFLER, SR THOMPSON, MO TSAO, JY PEERCY, PS AF HOGLUND, DE AZIZ, MJ STIFFLER, SR THOMPSON, MO TSAO, JY PEERCY, PS TI EFFECT OF NONEQUILIBRIUM INTERFACE KINETICS ON CELLULAR BREAKDOWN OF PLANAR INTERFACES DURING RAPID SOLIDIFICATION OF SI-SN SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID SILICON; VELOCITY; MOTION; MELT AB During rapid solidification, nonequilibrium interface kinetics alter the predictions of the Mullins-Sekerka theory for the stability of a planar interface against cellular breakdown. The velocity-dependence of the partition coefficient and of the Sn concentration at the onset of cellular breakdown have been measured during pulsed laser melting of Si-Sn alloys. The Mullins-Sekerka theory is modified by inserting a velocity-dependent partition coefficient and a velocity-dependent slope of the "kinetic liquidus", both of which are extracted from the continuous growth model for interface kinetics. These nonequilibrium interface kinetic effects increase the predicted critical concentration for cellular breakdown by two orders of magnitude for Sn in Si, and account fairly well for the experimental results. C1 CORNELL UNIV,DEPT MAT SCI & ENGN,ITHACA,NY 14853. SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP HOGLUND, DE (reprint author), HARVARD UNIV,DIV APPL SCI,CAMBRIDGE,MA 02138, USA. OI Thompson, Michael/0000-0002-4933-009X NR 29 TC 36 Z9 36 U1 2 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 107 EP 112 DI 10.1016/0022-0248(91)90164-Z PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300017 ER PT J AU BACEWICZ, R CISZEK, TF AF BACEWICZ, R CISZEK, TF TI LIQUID ENCAPSULATED CRYSTAL-GROWTH AND ELECTRICAL-PROPERTIES OF SB2SE3 AND BI2S3 SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID SINGLE-CRYSTALS; COMPENSATION AB Crystals of Bi2S3 and Sb2Se3 were grown by the liquid encapsulated solidification method. Dependence of their electrical resistivities on stoichiometry was studied. Sb2Se3 crystals grown after in situ synthesis are compensated and behave as an intrinsic-like material with a relatively narrow homogeneity range. Experimental data do not lend support to the hypothesis that the degenerate conductivity of some antimony selenide crystals is due to an excess of antimony. Instead, impurities and/or macroscopic defects could be responsible for a high hole concentration. Doping of both compounds was attempted. A self-compensation-like effect prevents Bi2S3 from undergoing n- to p-type conversion. It is possible to obtain p-type Sb2Se3 with relatively low resistivity by lead doping. However, both compounds exhibit quite weak sensitivity to impurities. C1 WARSAW POLYTECH INST,INST PHYS,PL-00662 WARSAW,POLAND. RP BACEWICZ, R (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. NR 18 TC 4 Z9 4 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 133 EP 136 DI 10.1016/0022-0248(91)90168-5 PG 4 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300021 ER PT J AU WANG, TH CISZEK, TF SCHUYLER, T AF WANG, TH CISZEK, TF SCHUYLER, T TI CHARGE CARRIER RECOMBINATION CENTERS IN HIGH-PURITY, DISLOCATION-FREE, FLOAT-ZONED SILICON DUE TO GROWTH-INDUCED MICRODEFECTS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID CRYSTALS AB Swirl defects (A- or B-type) and frozen-in defects are found to be carrier recombination centers in dislocation-free, as-grown, float-zoned Si crystals. The A-type defect has an effective carrier capture range of approximately 40-mu-m, as determined by EBIC analysis. The activation energy for forming the fast cooling frozen-in defects was estimated to be about 0.31 eV. Hydrogen doping can suppress swirl defect formation but causes other recombination centers. Defect formation can be changed by growth conditions, and long minority charge-carrier lifetimes are achieved through moderately high growth speeds and low thermal gradients during crystal growth, by which both swirl-defects and frozen-in defects are avoided. C1 SOLAR ENERGY RES INST, GOLDEN, CO 80401 USA. NR 18 TC 10 Z9 10 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 EI 1873-5002 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 155 EP 161 DI 10.1016/0022-0248(91)90172-2 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300025 ER PT J AU KIBBLER, AE KURTZ, SR OLSON, JM AF KIBBLER, AE KURTZ, SR OLSON, JM TI CARBON DOPING AND ETCHING OF MOCVD-GROWN GAAS, INP, AND RELATED TERNARIES USING CCL4 SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID CHEMICAL VAPOR-DEPOSITION; THERMODYNAMIC ANALYSIS; CVD AB Pure carbon tetrachloride is shown to be an excellent carbon-doping source for MOCVD-grown GaAs, but an etchant, rather than a doping source, for InP. Similar to the equilibria used in chloride vapor phase epitaxy, the etching (or reduced growth rate) is believed to occur because of the formation of InCl. In the case of Ga0.5IN0.5P, this etching is manifested by a change in the alloy composition, since the InP etches faster than the GaP. The composition of Ga0.5In0.5As is not changed significantly for comparable carbon tetrachloride flows. The doping efficiency of CCl4 for GaAs is shown to decrease sharply with the growth temperature and to be inversely proportional to the V/III ratio. The hole mobilities for carbon-doped GaAs are shown to be as high or higher than for zinc-doped GaAs. Compensation is not a problem, even at hole concentrations exceeding 10(19) cm-3. However, the quality of carbon-doped Ga0.5In0.5P films is significantly lower than that of zinc-doped Ga0.5In0.5P, and hole concentrations could not be increased above 10(17) cm-3. The carrier concentration of InP films is unaffected by the flow of carbon tetrachloride. RP KIBBLER, AE (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. NR 14 TC 27 Z9 27 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 258 EP 263 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300041 ER PT J AU BIEFELD, RM HEBNER, GA AF BIEFELD, RM HEBNER, GA TI GROWTH OF INSB ON GAAS BY METALORGANIC CHEMICAL VAPOR-DEPOSITION SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID MOLECULAR-BEAM EPITAXY; INAS1-XSBX; SUPERLATTICES; MBE AB High quality InSb epitaxial layers were grown on GaAs substrates by metalorganic chemical vapor deposition using a two-temperature growth procedure. Trimethylindium and triethyl- or trimethylantimony were used for the growth of InSb on GaAs. Transmission electron microscopy revealed the existence of a large number of misfit dislocations at the substrate-epitaxial layer interface and, in some samples, misoriented grains. The quality of the layers improved with thickness as indicated by transmission electron microscopy, X-ray rocking curve widths and Hall mobilities. The mobilities were correlated with surface roughness, X-ray rocking curve width and the Sb/In ratio. Hall mobilities up to 60,900 and 27,900 cm2/V.s were obtained at 300 and 77 K. respectively, on a 2.9-mu-m thick InSb layer. RP BIEFELD, RM (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 15 TC 22 Z9 22 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 272 EP 278 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300043 ER PT J AU CISZEK, TF EVANS, CD AF CISZEK, TF EVANS, CD TI SINGLE-CRYSTAL GROWTH AND LOW-FIELD AC MAGNETIC SUSCEPTOMETRY OF YBA2CU3O7-DELTA, ERBA2CU3O7-DELTA, AND BI2SR2CA0.8CU2O8 SUPERCONDUCTORS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH AB We obtained single-crystal YBa2Cu3O7-delta and ErBa2Cu3O7-delta platelets by eutectic growth from CuO-rich mixtures of Y2O3 (or Er2O3), BaCO3, and CuO. Ground and mixed powders were loaded in an alumina crucible and heated to 1150-1180-degrees-C in air, held for 0.5-2 h, then cooled under programmed temperature and time conditions. Individual crystals of both YBa2Cu3O7-delta and ErBa2Cu3O7-delta up to 4 mm wide have been grown in voids that form in the charge. Similarly, compositions and temperature programs that allow single-crystal growth of Bi-Sr-Ca-Cu-O platelet crystals up to 4 mm wide that resembled mica in their delamination tendency were found. Low field AC magnetic susceptometry was used to characterize the temperature dependence of the superconducting transition in small single crystals of the three superconductors. Both the real chi' and imaginary chi" components of magnetic susceptibility were measured. RP CISZEK, TF (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. NR 5 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 418 EP 425 PG 8 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300064 ER PT J AU LIU, JZ JIA, YX KLAVINS, P SHELTON, RN DOWNEY, J LAM, DJ AF LIU, JZ JIA, YX KLAVINS, P SHELTON, RN DOWNEY, J LAM, DJ TI PREPARATION AND MAGNETIC MEASUREMENTS OF SINGLE-CRYSTAL TL2BA2CACU2O8 SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID CRITICAL CURRENTS; MODEL AB A novel self-flux growth technique has been used to prepare superconducting single crystals with transition temperatures, T(c), ranging from 105 to 124 K in the Tl-Ca-Ba-Cu-O system. Measurements of the magnetic hysteresis and magnetic relaxation in Tl2Ba2CaCu2O8 crystals reveal extraordinary flux creep behavior that persists at low temperatures. These effects are attributed to the lack of effective pinning centers in these materials. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP LIU, JZ (reprint author), UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616, USA. NR 9 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 436 EP 440 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300067 ER PT J AU VENTURINI, EL TIGGES, CP BAUGHMAN, RJ MOROSIN, B BARBOUR, JC MITCHELL, MA GINLEY, DS AF VENTURINI, EL TIGGES, CP BAUGHMAN, RJ MOROSIN, B BARBOUR, JC MITCHELL, MA GINLEY, DS TI STOICHIOMETRY AND IRRADIATION EFFECTS IN MELT GROWN TL-CA-BA-CU-O SINGLE-CRYSTALS SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 8TH AMERICAN CONF ON CRYSTAL GROWTH ( ACCG-8 ) CY JUL 15-20, 1990 CL VAIL, CO SP AMER ASSOC CRYSTAL GROWTH ID BULK SUPERCONDUCTIVITY; ZERO RESISTANCE; 120-K; TEMPERATURES; CURRENTS; SYSTEMS; FILMS; MODEL AB Melt-grown crystals in the Tl-Ca-Ba-Cu-O system with the same structure type can have substantial differences in the superconducting transition, both in width and onset temperature. These differences are attributed to stoichiometry variations arising from cation site substitution. Magnetization and electrical resistivity data are presented which emphasize the extreme sensitivity of the superconductivity to the exact stoichiometry in this system. High quality single crystals exhibit large flux creep due to a weak pinning potential for magnetic flux lines. Flux pinning and thus the critical current density are shown to be significantly enhanced by irradiation with high-energy protons or neutrons. RP VENTURINI, EL (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 25 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP 441 EP 446 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300068 ER PT J AU BOATNER, LA CISZEK, TF AF BOATNER, LA CISZEK, TF TI 8TH AMERICAN CONFERENCE ON CRYSTAL-GROWTH, ACCG-8, VAIL, COLORADO, USA, 15-20 JULY 1990 - PREFACE SO JOURNAL OF CRYSTAL GROWTH LA English DT Editorial Material C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP BOATNER, LA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. 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 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP R10 EP R11 PG 2 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300002 ER PT J AU BONNER, WA SUREK, T AF BONNER, WA SUREK, T TI 8TH AMERICAN CONFERENCE ON CRYSTAL-GROWTH, ACCG-8, VAIL, COLORADO, USA, 15-20 JULY 1990 - PREFACE SO JOURNAL OF CRYSTAL GROWTH LA English DT Editorial Material C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP BONNER, WA (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. 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 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD FEB PY 1991 VL 109 IS 1-4 BP R9 EP R9 PG 1 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA FB603 UT WOS:A1991FB60300001 ER PT J AU HIRVONEN, JP KOSKINEN, J LAPPALAINEN, R ANTTILA, A TRKULA, M AF HIRVONEN, JP KOSKINEN, J LAPPALAINEN, R ANTTILA, A TRKULA, M TI DIRECT, MASS-ANALYZED ION-BEAM AND ARC-DISCHARGE DEPOSITION OF DIAMOND-LIKE FILMS SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE DIAMOND-LIKE FILM; ION BEAM DEPOSITION; ARC DISCHARGE TECHNIQUE ID AMORPHOUS-CARBON; ENERGY; C+ AB Utilizing mass-analyzed carbon beams at an energy range of 10 eV to 2 keV, we can fabricate diamondlike films with direct deposition. This process allows a very precise adjustment of deposition parameters such as ion energy, ion current density, angle of incidence, and control of impurities at an isotopic level. We obtained a density of 3.3-3.5 g/cm3, which is very close to the corresponding values of natural diamond. The most serious disadvantage of direct deposition is a low growth rate. Using an arc-discharge method provides more feasible deposition rates while simultaneously retaining many beneficial effects of direct deposition. These results were also confirmed by spectroscopic studies that revealed similar characteristics on both films. This paper reviews deposition of diamondlike films produced with direct, mass-analyzed ion-beam and arc-discharge methods and presents some properties of these films. C1 UNIV HELSINKI, DEPT PHYS, SF-00170 HELSINKI 17, FINLAND. RP HIRVONEN, JP (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, DIV MAT SCI & TECHNOL, LOS ALAMOS, NM 87545 USA. RI Koskinen, Jari/J-3886-2014 NR 30 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0361-5235 EI 1543-186X J9 J ELECTRON MATER JI J. Electron. Mater. PD FEB PY 1991 VL 20 IS 2 BP 127 EP 132 DI 10.1007/BF02653313 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA EX698 UT WOS:A1991EX69800003 ER PT J AU KVAM, EP WASHBURN, J ALLEN, LP ZAVRACKY, PM AF KVAM, EP WASHBURN, J ALLEN, LP ZAVRACKY, PM TI MATERIALS STUDY OF SILICON-ON-INSULATOR MATERIAL BY TEM SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE SILICON-ON-INSULATOR; DISLOCATIONS; ISOLATED SI EPITAXY ID SOI MOSFETS AB Silicon-on-insulator (SOI) technology addresses the need for many different device applications, such as radiation tolerant devices, high voltage, and and three-dimensional circuitry applications. Isolated silicon epitaxy (ISE) is a commercialised process which results in excellent SOI material quality with proven results, having overcome most of the obstacles of other processes, although only having reduced, not eliminated, threading dislocations. The remaining isolated dislocations have been examined in detail by transmission electron microscopy (TEM). These have been diagnosed as normal lattice dislocations, with no faults or twins in the material. The nature, source, and behavior of the remaining dislocations is discussed. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. KOPIN CORP,TAUNTON,MA 02780. RI Kvam, Eric/A-2457-2010 NR 12 TC 0 Z9 0 U1 1 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD FEB PY 1991 VL 20 IS 2 BP 151 EP 153 DI 10.1007/BF02653316 PG 3 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA EX698 UT WOS:A1991EX69800006 ER PT J AU WASHBURN, J KVAM, EP LILIENTALWEBER, Z AF WASHBURN, J KVAM, EP LILIENTALWEBER, Z TI DEFECT FORMATION IN EPITAXIAL CRYSTAL-GROWTH SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE MBE; DEFECTS; TEM ID GEXSI1-X/SI(100) HETEROSTRUCTURES; DISLOCATION NUCLEATION; MISFIT DISLOCATIONS; CRITICAL THICKNESS; STRAIN; PROPAGATION; RELAXATION; DENSITY; LAYERS; FILMS AB Factors affecting the nucleation and propagation of dislocations, stacking faults, micro-twins, and inversion domain boundaries in epitaxially grown semiconductor layers are reviewed, with examples for heteroepitaxial MBE-grown layers on substrates having varying degrees of mismatch or different crystal symmetry. Mechanisms for generation of defects at the heterointerface and in the epilayer are discussed. For epilayers with bulk mismatch from 0 to 4%, methods for reducing defect density in the epitaxial layer are considered. Examples of structural details in the epilayers and at heterionterfaces, particularly those which may be revealed by transmission electron microscopy, are given. RP WASHBURN, J (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. RI Kvam, Eric/A-2457-2010; Liliental-Weber, Zuzanna/H-8006-2012 NR 31 TC 8 Z9 8 U1 1 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD FEB PY 1991 VL 20 IS 2 BP 155 EP 161 DI 10.1007/BF02653317 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA EX698 UT WOS:A1991EX69800007 ER PT J AU LEE, HP LIU, XM MALLOY, K WANG, S GEORGE, T WEBER, ER LILIENTALWEBER, Z AF LEE, HP LIU, XM MALLOY, K WANG, S GEORGE, T WEBER, ER LILIENTALWEBER, Z TI STRUCTURAL CHARACTERIZATIONS OF INITIAL NUCLEATION OF GAAS ON SI FILMS GROWN BY MODULATED MOLECULAR-BEAM EPITAXY SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE GAAS/SI HETEROEPITAXY; NUCLEATION; DISLOCATIONS ID MIGRATION-ENHANCED EPITAXY; HIGH-QUALITY GAAS; CRYSTALLINE QUALITY; IMPROVEMENT; INTERFACE; LAYERS AB Structural characterizations by plan-view and high resolution cross-sectional transmission electron microscopy (TEM) on 150angstrom thick GaAs on Si films grown by a modulated molecular beam (MMBE) technique and conventional molecular beam epitaxy (MBE) at 300-degrees-C are reported. From the coverage of Moire interference fringes on plan-view electron micrographs, it is found that the nucleation of GaAs deposited by MMBE is more two-dimensional than conventional MBE. High resolution cross-sectional TEM micrographs show that the interfacial defects consist almost solely of partial dislocations for both samples. A model is constructed to explain this phenomenon by considering the magnitude of strain relieved by each type of misfit dislocation relative to its energy of formation. The effect of thermal annealing on the interfacial defect structures of these samples is also reported. C1 UNIV CALIF BERKELEY,DEPT ELECT ENGN & COMP SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,ELECTR RES LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. RI Liliental-Weber, Zuzanna/H-8006-2012; Malloy, Kevin/E-5994-2010 NR 24 TC 11 Z9 11 U1 0 U2 4 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD FEB PY 1991 VL 20 IS 2 BP 179 EP 186 DI 10.1007/BF02653321 PG 8 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA EX698 UT WOS:A1991EX69800011 ER PT J AU ONG, PH ANG, SS BROWN, WD NASEEM, HA ULRICH, RK DRESSENDORFER, PV AF ONG, PH ANG, SS BROWN, WD NASEEM, HA ULRICH, RK DRESSENDORFER, PV TI ARSENIC-IMPLANTED THIN-FILM PECVD SEMI-INSULATING POLYSILICON (SIPOS) RESISTORS SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article DE PECVD; SIPOS; RESISTOR; THIN FILM RESISTOR; ION IMPLANTATION ID SILICON AB Thin film (2000A-angstrom) PECVD SIPOS resistors were fabricated using arsenic implantation and rapid thermal annealing. The current-voltage characteristics are symmetrical and field-dependent. The resistivity (as low as 0.2 ohm-cm) is shown to be a function of the oxygen content of the as-deposited material, the implant dose, and the annealing temperature. The variation of resistance with operating temperature also decreases with increasing dose and annealing temperature. As expected, the lowest resistivity is obtained for films with high refractive indices or alternatively, low oxygen content. C1 UNIV ARKANSAS,DEPT CHEM ENGN,FAYETTEVILLE,AR 72701. SANDIA NATL LABS,DIV 2144,ALBUQUERQUE,NM 87185. RP ONG, PH (reprint author), UNIV ARKANSAS,DEPT ELECT ENGN,FAYETTEVILLE,AR 72701, USA. NR 11 TC 6 Z9 6 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD FEB PY 1991 VL 20 IS 2 BP 211 EP 215 DI 10.1007/BF02653326 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA EX698 UT WOS:A1991EX69800016 ER PT J AU ABNEY, KD BALL, GR ELLER, PG AF ABNEY, KD BALL, GR ELLER, PG TI VAPOR-PRESSURE STUDIES OF THE HYDROGEN FLUORIDE-ANTIMONY PENTAFLUORIDE SYSTEM SO JOURNAL OF FLUORINE CHEMISTRY LA English DT Article AB Vapor pressure data are reported for the hydrogen fluoride-antimony pentafluoride binary liquid system over the full compositional range (0 - 100 mole % SbF5) and temperature range (233 - 293K) commonly used in reaction chemistry of this superacid system. RP ABNEY, KD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV ISOTOPE & NUCL CHEM,LOS ALAMOS,NM 87545, USA. NR 13 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-1139 J9 J FLUORINE CHEM JI J. Fluor. Chem. PD FEB PY 1991 VL 51 IS 2 BP 165 EP 170 DI 10.1016/S0022-1139(00)80287-0 PG 6 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA FA927 UT WOS:A1991FA92700002 ER PT J AU CHEN, L HASEGAWA, A AF CHEN, L HASEGAWA, A TI KINETIC-THEORY OF GEOMAGNETIC-PULSATIONS .1. INTERNAL EXCITATIONS BY ENERGETIC PARTICLES SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PERIOD MAGNETIC PULSATIONS; BALLOONING INSTABILITY; HYDROMAGNETIC-WAVES; GEOSTATIONARY ORBIT; MAGNETOSPHERE; PLASMA; EIGENMODE; DENSITIES AB Motivated by recent satellite observations, we have carried out a comprehensive theoretical analysis on the generation of hydromagnetic Alfven waves in a realistic magnetospheric plasma environment consisting of a core (approximately 100 eV) component and and energetic (approximately 10 keV) component. Our theoretical formulation employs the gyrokinetic equations and, thus, retains anisotropy, finite Larmor radii, magnetic trapping, and wave-particle interactions in addition to nonuniform plasma equilibria. A set of coupled equations for transverse and compressional magnetic perturbations is derived and analyzed for its stabilities assuming equilibrium distribution functions which are interchange stable. Our findings are as follows: (1) compressional and transverse shear Alfven oscillations are generally coupled in realistic plasmas; (2) in the decoupled limit, for the compressional wave branch, one recovers the drift mirror instability due to the Landau resonances and tau = 1 + 4-pi(partial-derivative P perpendicular-to /B partial-derivative B) < 0; here, P perpendicular-to = P perpendicular-to (psi, B) is the perpendicular pressure and psi is the magnetic flux function; (3) for the decoupled transverse shear Alfven branch, one obtains the drift Alfven ballooning instability due to the Landau resonances and free energy of the pressure gradient for tau > 0; (4) for both branches, the most unstable modes have antisymmetric structures and propagate in the diamagnetic drift direction of the energetic ions; and (5) finite coupling can be shown to further enhance the drift Alfven ballooning instabilities. Thus we conclude that for tau greater-than-or-equal-to 0, the coupled drift Alfven ballooning mirror instability constitutes an important internal generating mechanism of geomagnetic pulsations. The various predicted features of this instability are consistent with satellite observations. C1 PRINCETON UNIV,DEPT ASTROPHYS SCI,PRINCETON,NJ 08543. AT&T BELL LABS,MURRAY HILL,NJ 07974. RP CHEN, L (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. RI chen, liu/I-2297-2013 NR 31 TC 162 Z9 166 U1 1 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1503 EP 1512 DI 10.1029/90JA02346 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600037 ER PT J AU BIRN, J HESSE, M AF BIRN, J HESSE, M TI THE SUBSTORM CURRENT WEDGE AND FIELD-ALIGNED CURRENTS IN MHD SIMULATIONS OF MAGNETOTAIL RECONNECTION SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID AMPLITUDE DISTRIBUTION; SOLAR-WIND; GENERATION; MAGNETOSPHERE; TRIAD AB We present results of a three-dimensional MHD simulation of magnetotail reconnection, which, in contrast to earlier ones, starts from an equilibrium configuration that contains a region 1 type field-aligned current system at the plasma sheet/lobe boundary. This current system is found from equilibrium theory as the consequence of boundary conditions, which require that field lines at large distances from the Earth become aligned with the tail axis, consistent with observations and the expected consequences of the interaction with the solar wind. As in earlier simulations, the dynamic evolution develops from a slow diffusion to the fast growth of a three-dimensional tearing mode, initiated by the sudden occurrence or increase of resistivity, leading again to the formation and subsequent tailward ejection of a plasmoid, associated with fast plasma flows. In addition, we find changes of the electric current system which are consistent with the substorm current wedge picture inferred from observations, i.e., a deviation of cross-tail current from a near-Earth tail region toward the Earth on the dawn side and away on the dusk side, associated with filed-aligned currents of the same signature. While the total cross-tail is reduced at the location of the near-Earth reconnection site, the local current density at the near-Earth X line actually increased, consistent with the strong plasma sheet thinning in that region. The source regions of the field-aligned currents, indicated by strong peaks of DELTA.j parallel-to, are identified as regions of strong plasma flow vorticity near the boundaries of the fast earthward flow earthward of the reconnection site. This flow shear increases preexisting magnetic shear resulting in an increased twist of magnetic flux tubes connected with these regions and thus a generation or increase of the field-aligned currents. We note that the current diversion in our simulation is not caused by a locally enhanced resistivity (although in reality this might be the case) but by the localization of reconnection in a three-dimensional tail configuration. RP BIRN, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. RI Hesse, Michael/D-2031-2012 NR 14 TC 103 Z9 105 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1611 EP 1618 DI 10.1029/90JA01762 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600045 ER PT J AU ONSAGER, TG WINSKE, D THOMSEN, MF AF ONSAGER, TG WINSKE, D THOMSEN, MF TI INTERACTION OF A FINITE-LENGTH ION-BEAM WITH A BACKGROUND PLASMA - REFLECTED IONS AT THE QUASI-PARALLEL BOW SHOCK SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTROMAGNETIC INSTABILITIES DRIVEN; FREQUENCY UPSTREAM WAVES; SOLAR-WIND; DIAMAGNETIC CAVITIES; COLLISIONLESS SHOCKS; EXCITATION MECHANISM; ISEE-2 OBSERVATIONS; CURRENT SHEET; ALFVEN WAVES; SIMULATIONS AB The coupling of a finite-length, field-aligned, ion beam with a uniform background plasma is investigated using one-dimensional hybrid computer simulations. The finite-length beam is used to study the interaction between the incident solar wind and ions reflected from the Earth's quasi-parallel bow shock, where the reflection process may vary with time. The coupling between the reflected ions and the solar wind is relevant to ion heating at the bow shock and possibly to the formation of hot, flow anomalies and re-formation of the shock itself. We find that although there are many similarities between the instabilities driven by the finite-length beam and those predicted by linear theory for an infinite, homogeneous beam, there are also some important differences. Consistent with linear theory, the waves which dominate the interaction are the electromagnetic right-hand polarized resonant and nonresonant modes. However, in addition to the instability growth rates, the length of time that the waves are in contact with the beam is also an important factor in determining which wave mode will dominate the interaction. Whereas linear theory predicts the nonresonant mode to have the larger growth rate for the parameters we investigate, with a finite-length beam we find that both the nonresonant and resonant modes contribute to the interaction. We find that the interaction will result in strong coupling, where a significant fraction of the available free energy is converted into thermal energy in a short time, provided the beam is sufficiently dense or sufficiently long. RP ONSAGER, TG (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 47 TC 36 Z9 36 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 0148-0227 J9 J GEOPHYS RES JI J. Geophys. Res-Space Phys. PD FEB 1 PY 1991 VL 96 IS A2 BP 1775 EP 1788 DI 10.1029/90JA02008 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA EW666 UT WOS:A1991EW66600059 ER PT J AU KOLLIE, TG RADCLIFF, TD WEAVER, FJ AF KOLLIE, TG RADCLIFF, TD WEAVER, FJ TI EMITTANCE OF BOEHMITE AND ALUMINA FILMS ON 6061-ALUMINUM ALLOY BETWEEN 295-K AND 773-K SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article DE HIGH-TEMPERATURE PHENOMENA; RADIATION; THERMOPHYSICAL PROPERTIES AB The total hemispherical emittance of an oxide film that formed on 6061-T6 aluminum alloy parts in the Tower Shielding Reactor-II at Oak Ridge National Laboratory was measured from 295 to 773 K using an emissiometer and/or a calorimeter. The emittance of this film was critically needed for heat transfer calculations in a simulated loss-of-coolant accident of the reactor. X-ray diffraction analysis identified the film as boehmite (Al2O3.H2O), which dehydrated to alumina (Al2O3) upon heating above 473 K. The measured emittances for the alumina film are in excellent agreement with published values for anodized aluminum films and for bulk alumina. Published values of the emittance of boehmite could not be found for comparison, but evidence is presented that some anodization processes for aluminum yield boehmite and not alumina films. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 15 TC 1 Z9 1 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD FEB PY 1991 VL 113 IS 1 BP 185 EP 189 DI 10.1115/1.2910523 PG 5 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HP758 UT WOS:A1991HP75800024 ER PT J AU DUIGNAN, MR GREENE, GA IRVINE, TF AF DUIGNAN, MR GREENE, GA IRVINE, TF TI FILM BOILING HEAT-TRANSFER TO LARGE SUPERHEATS FROM A HORIZONTAL FLAT SURFACE SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Note DE BOILING; HIGH-TEMPERATURE PHENOMENA; PHASE-CHANGE PHENOMENA C1 SUNY STONY BROOK,DEPT MECH ENGN,STONY BROOK,NY 11794. WESTINGHOUSE SAVANNAH RIVER CO,SAVANNAH RIVER LAB,AIKEN,SC 29802. BROOKHAVEN NATL LAB,DEPT NUCL ENGN,UPTON,NY 11973. NR 16 TC 1 Z9 1 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD FEB PY 1991 VL 113 IS 1 BP 266 EP 268 DI 10.1115/1.2910543 PG 3 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA HP758 UT WOS:A1991HP75800043 ER PT J AU LIU, C BADER, SD AF LIU, C BADER, SD TI MAGNETIC-PROPERTIES OF ULTRATHIN EPITAXIAL-FILMS OF IRON SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT SYMP OF THE 1990 SPRING CONF OF THE EUROPEAN MATERIALS RESEARCH SOC : MAGNETIC THIN FILMS, MULTILAYERS AND SUPERLATTICES CY MAY 29-JUN 01, 1990 CL STRASBOURG, FRANCE SP EUROPEAN MAT RES SOC, CNRS, IBM, ALMADEN RES, IBM GERMANY, PHILIPS EINDHOVEN, DUPONT CO, SIEMENS GERMANY ID PERPENDICULAR SURFACE ANISOTROPY; KERR-EFFECT OBSERVATION; FERROMAGNETIC-FILMS; CRITICAL-BEHAVIOR; PHASE-TRANSITION; FE FILMS; METALS AB Ultrathin Fe films epitaxially grown on Cu(100), Au(100), Pd(100) and Ru(0001) substrates are used to study monolayer magnetism, surface magnetic anisotropy and two-dimensional (2D) critical behavior, by means of in-situ surface magneto-optical Kerr-effect measurements. Epitaxial structures and growth modes are characterized by auxiliary low-energy electron diffraction and Auger electron studies. The magnetic properties of the films depend on the growth temperature. For 100 K growth, all films exhibit a universal behavior of perpendicular spin orientations in the monolayer regime, while for 300 K growth, Fe/Pd(100) and Fe/Au(100) have in-plane easy-axis of magnetization for all thicknesses. Fe/Ru(0001) lacks a ferromagnetic response for thicknesses less than two monolayers (ML). Fe/Pd(100) has remarkable thermal stability in the monolayer and submonolayer range. Reversible magnetization data are obtained for 0.6 to 3.0 ML thick films, which show second-order phase transitions at thickness-dependent Curie temperatures (T(C)). An effective magnetization exponent beta-eff of 0.127 +/- 0.004 is obtained for a 1.2 ML Fe/Pd (100) film, in agreement with the theoretical value of beta-c = 0.125 for an ideal 2D Ising model. The T(C) trend with film thickness for Fe/Pd(100) is also in agreement with Monte Carlo calculations for Ising films. RP LIU, C (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Bader, Samuel/A-2995-2013 NR 36 TC 34 Z9 34 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD FEB PY 1991 VL 93 BP 307 EP 314 DI 10.1016/0304-8853(91)90352-B PG 8 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA FP221 UT WOS:A1991FP22100060 ER PT J AU SCRIBNER, KT SMITH, MH GARROTT, RA CARPENTER, LH AF SCRIBNER, KT SMITH, MH GARROTT, RA CARPENTER, LH TI TEMPORAL, SPATIAL, AND AGE-SPECIFIC CHANGES IN GENOTYPIC COMPOSITION OF MULE DEER SO JOURNAL OF MAMMALOGY LA English DT Article ID WHITE-TAILED DEER; MOOSE ALCES-ALCES; GENETIC-VARIATION; NORTHWEST COLORADO; POCKET GOPHERS; F-STATISTICS; POPULATIONS; VARIABILITY; DIFFERENTIATION; HETEROZYGOSITY AB Spatial, temporal, and age-specific genetic variation is described for a mule deer (Odocoileus hemionus) herd from northwestern Colorado during 1983-1986. Little genetic differentiation was observed between major migratory herd subdivisions, although spatial structuring and inbreeding within subdivisions is indicated during some years. Significant differences in common allele frequencies at six of 11 variable loci and changes in apportionment of genetic variance among individuals within and among locations occurred during 4 years of study. Common allele frequencies increased with year of study. Significant differences in allele frequencies also were observed between fawns and adult females. Temporal and age-specific genetic differences probably were influenced most by changes in breeding structure. C1 UNIV GEORGIA,DEPT ZOOL,ATHENS,GA 30602. UNIV MINNESOTA,DEPT FISHERIES & WILDLIFE,ST PAUL,MN 55108. COLORADO DIV WILDLIFE,RES CTR,FT COLLINS,CO 80526. RP SCRIBNER, KT (reprint author), SAVANNAH RIVER ECOL LAB,DRAWER E,AIKEN,SC 29801, USA. NR 47 TC 25 Z9 27 U1 1 U2 5 PU AMER SOC MAMMALOGISTS PI PROVO PA BRIGHAM YOUNG UNIV, DEPT OF ZOOLOGY, PROVO, UT 84602 SN 0022-2372 J9 J MAMMAL JI J. Mammal. PD FEB PY 1991 VL 72 IS 1 BP 126 EP 137 DI 10.2307/1381987 PG 12 WC Zoology SC Zoology GA EY283 UT WOS:A1991EY28300013 ER PT J AU COST, JR STANLEY, JT AF COST, JR STANLEY, JT TI INTERNAL-FRICTION DUE TO OXYGEN RELAXATION IN SUPERCONDUCTING YBA2CU3O7-DELTA ABOVE TC SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID YBA2CU3O7-DELTA; DIFFUSION; TEMPERATURE; TRANSITION; KINETICS AB YB2Cu3O7-delta has an internal friction peak near 210-degrees-C measured at 1.18 Hz. The shift in the temperature of this peak with frequency as measured with different internal friction techniques indicates that the relaxation process has an average activation energy of 1.14 +/- 0.05 eV and a pre-exponential factor, tau-0 = 1.5 x 10(-13) s (log tau-0 = -12.82 +/- 0.23). The peak height decreases during annealing at above 375-degrees-C in helium and increases when annealed in oxygen. The mechanism fo rthe relaxation is believed to be the stress-induced motion of oxygen atoms in the Cu-O plane. Detailed analysis shows that the internal friction peak is determined by a spectrum of activation energies; this spectrum is a symmetrical single peak 0.12 eV wide at half-height. Models for the relaxation are considered and the resulting diffusivities are compared to tracer diffusion results. C1 ARIZONA STATE UNIV,TEMPE,AZ 85281. RP COST, JR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 28 TC 36 Z9 36 U1 0 U2 1 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 1991 VL 6 IS 2 BP 232 EP 243 DI 10.1557/JMR.1991.0232 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA EW655 UT WOS:A1991EW65500004 ER PT J AU MEYER, HM HILL, DM WEAVER, JH GORETTA, KC BALACHANDRAN, U AF MEYER, HM HILL, DM WEAVER, JH GORETTA, KC BALACHANDRAN, U TI NI/YBA2CU3O7-X AND NI/BI2SR2CA0.8Y0.2CU2OX INTERFACE FORMATION - REACTIVITY, SEGREGATION, AND CHEMICAL TRAPPING SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SINGLE-CRYSTALLINE; OXYGEN; CU; BI2CA1+XSR2-XCU2O8+Y; YBA2CU3O7-X; SURFACES; SUPERCONDUCTOR; PASSIVATION; ADATOMS; OXIDES AB Interfaces formed by condensing Ni atoms onto YBa2Cu3O7-x (Y-123) and Bi2Sr2Ca0.8Y0.2Cu2O(x) (Bi-2212) have been studied with x-ray photoelectron spectroscopy. For both Y-123 and Bi-2212, the Ni 2p3/2 and O 1s core level features indicate Ni-O reactions and changes in the Cu 2p3/2 emission that reflect reduction from nominal Cu2+ to Cu1+ oxidation states. Ni deposition onto Bi-2212 also reduces Bi-O bonding and releases Bi atoms. For Ni/Y-123, analysis of emission intensities as a function of coverage shows that O and Ba intermix in the growing metal overlayer but that Cu is trapped at the buried interface. For Ni/Bi-2212, similar analysis shows O and Bi intermixing but less effective Cu trapping. C1 ARGONNE NATL LAB,ARGONNE,IL 60439. RP MEYER, HM (reprint author), UNIV MINNESOTA,DEPT CHEM ENGN & MAT SCI,MINNEAPOLIS,MN 55455, USA. NR 26 TC 5 Z9 5 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 1991 VL 6 IS 2 BP 270 EP 277 DI 10.1557/JMR.1991.0270 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA EW655 UT WOS:A1991EW65500008 ER PT J AU HOLZMAN, LM ADAMS, JB FOILES, SM HITCHON, WNG AF HOLZMAN, LM ADAMS, JB FOILES, SM HITCHON, WNG TI PROPERTIES OF THE LIQUID-VAPOR INTERFACE OF FCC METALS CALCULATED USING THE EMBEDDED ATOM METHOD SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SURFACE-TENSION; ALLOYS; NI; CU AB The Embedded Atom Method (EAM) is used to compute density, internal energy, and structure factor for bulk liquids of the fcc metals at several temperatures above and below the melting temperature. The calculated values are found to be in generally good agreement with experiment, although the volume expansion upon melting does differ by up to 50% from the expected result for some of the elements studied. The total energy of a liquid system with surfaces is calculated, and the results are compared with the bulk liquid results to determine the enthalpy and thickness of the liquid-vapor interface. Also, the surface tension is found for Cu near the melting temperature. The EAM values for surface enthalpy and surface tension are found to be smaller than experimental values, which is consistent with results for EAM calculations of the surface energy of crystalline solids. C1 UNIV ILLINOIS,DEPT MAT SCI & ENGN,URBANA,IL 61801. SANDIA NATL LABS,LIVERMORE,CA 94550. RP HOLZMAN, LM (reprint author), UNIV WISCONSIN,MAT SCI PROGRAM,MADISON,WI 53706, USA. OI Foiles, Stephen/0000-0002-1907-454X NR 15 TC 24 Z9 27 U1 1 U2 1 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 1991 VL 6 IS 2 BP 298 EP 302 DI 10.1557/JMR.1991.0298 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA EW655 UT WOS:A1991EW65500011 ER PT J AU GOODS, SH AF GOODS, SH TI THE EVOLUTION OF DAMAGE IN TRITIUM EXPOSED COPPER SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID GROWTH; SILVER; CREEP AB Severe microstructural damage has been observed in polycrystalline OFHC copper specimens thermally exposed to high pressure tritium gas at temperatures less-than-or-equal-to 200-degrees-C, but not at 300-degrees-C. No such damage occurs in single crystal specimens exposed under identical conditions, regardless of temperature. In the polycrystals, the damage takes the form of very flat, crack-like intergranular cavities. It is found that the cavitation evolves slowly with time. For short exposure times, cavities as small as 0.1-mu-m are observed. In specimens subjected to the longest aging times, the cavities grow and link until entire grain boundary facets fail. The driving force for the growth of these cavities is attributed to the internal gas pressure of helium-3 generated by the decay of tritium. The growth kinetics of the cavity microstructure are described by a coupled grain boundary, surface self-diffusion process. The tritium exposure profoundly affects the mechanical properties of the polycrystalline material, inducing a severe loss in ductility. In concert with the observed ductility loss is a change in fracture morphology from transgranular ductile rupture to intergranular fracture. Examination of the resulting grain boundary facets reveals a dimple structure. The spacing of these dimples can be correlated with the spacing of the exposure-induced grain boundary cavities. RP GOODS, SH (reprint author), SANDIA NATL LABS,TRITIUM EFFECTS RES DIV,LIVERMORE,CA 94550, USA. NR 30 TC 2 Z9 2 U1 0 U2 0 PU MATERIALS RESEARCH SOCIETY PI PITTSBURGH PA 9800 MC KNIGHT ROAD SUITE 327, PITTSBURGH, PA 15237 SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 1991 VL 6 IS 2 BP 303 EP 313 DI 10.1557/JMR.1991.0303 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA EW655 UT WOS:A1991EW65500012 ER PT J AU HSUEH, CH BRIGHT, JD SHETTY, DK AF HSUEH, CH BRIGHT, JD SHETTY, DK TI INTERFACIAL PROPERTIES OF SIC-BOROSILICATE GLASS COMPOSITES EVALUATED FROM PUSHOUT AND PULLOUT TESTS SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article ID CERAMIC-MATRIX COMPOSITES; SHEAR-STRESS; FIBER; FRICTION; FRACTURE C1 UNIV UTAH,DEPT MAT SCI & ENGN,SALT LAKE CITY,UT 84112. RP HSUEH, CH (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. RI Hsueh, Chun-Hway/G-1345-2011; OI Shetty, Dinesh/0000-0003-4132-1372 NR 17 TC 5 Z9 5 U1 0 U2 0 PU CHAPMAN HALL LTD PI LONDON PA 2-6 BOUNDARY ROW, LONDON, ENGLAND SE1 8HN SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD FEB 1 PY 1991 VL 10 IS 3 BP 135 EP 138 DI 10.1007/BF02352826 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA EV579 UT WOS:A1991EV57900005 ER PT J AU CHANNELL, PJ AF CHANNELL, PJ TI STABLE SYMPLECTIC MAPS SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article ID CONSERVATIVE SYSTEMS; GENERIC PROPERTIES AB For a symplectic vector space of arbitrary even dimension it is shown how to construct an infinite class of nonlinear sympletic maps of the space that are absolutely stable, i.e., have invariant closed balls. Explicit examples are presented. RP CHANNELL, PJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,AT-6 & CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545, USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD FEB PY 1991 VL 32 IS 2 BP 408 EP 412 DI 10.1063/1.529426 PG 5 WC Physics, Mathematical SC Physics GA EU886 UT WOS:A1991EU88600011 ER PT J AU TIPPETT, MK ZIOLKOWSKI, RW AF TIPPETT, MK ZIOLKOWSKI, RW TI A BIDIRECTIONAL WAVE TRANSFORMATION OF THE COLD-PLASMA EQUATIONS SO JOURNAL OF MATHEMATICAL PHYSICS LA English DT Article AB The bidirectional wave transformation developed for scalar equations is shown to have interesting extensions for first-order hyperbolic systems. Assuming a localized waveform of the solution gives an equation for the envelope of the localized wave. The type of the envelope equation depends on the characteristics of the original hyperbolic equations, and the speed of the localized wave. This method is applied to the cold plasma equations. In the general case integral representations are found for the fundamental solutions; and in a special case, exact solutions are constructed. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP TIPPETT, MK (reprint author), NYU,COURANT INST MATH SCI,NEW YORK,NY 10012, USA. RI Tippett, Michael/C-6286-2011 OI Tippett, Michael/0000-0002-7790-5364 NR 7 TC 11 Z9 11 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0022-2488 J9 J MATH PHYS JI J. Math. Phys. PD FEB PY 1991 VL 32 IS 2 BP 488 EP 492 DI 10.1063/1.529440 PG 5 WC Physics, Mathematical SC Physics GA EU886 UT WOS:A1991EU88600025 ER PT J AU DING, YS FOWLER, JS GATLEY, SJ DEWEY, SL WOLF, AP AF DING, YS FOWLER, JS GATLEY, SJ DEWEY, SL WOLF, AP TI SYNTHESIS OF HIGH SPECIFIC ACTIVITY (+)-6-[F-18]FLUORONOREPINEPHRINE AND (-)-6-[F-18]FLUORONOREPINEPHRINE VIA THE NUCLEOPHILIC AROMATIC-SUBSTITUTION REACTION SO JOURNAL OF MEDICINAL CHEMISTRY LA English DT Article ID HEART; RESOLUTION; INVIVO AB The first example of a no-carrier-added F-18-labeled catecholamine, 6-[F-18]fluoronorepinephrine (6-[F-18]FNE), has been synthesized via nucleophilic aromatic substitution. The racemic mixture was resolved on a chiral HPLC column to obtain pure samples of (-)-6-[F-18]FNE and (+)6-[F-18]FNE. Radiochemical yields of 20% at the end of bombardment (EOB) for the racemic mixture (synthesis time 93 min), 6% for each enantiomer (synthesis time 128 min) with a specific activity of 2-5 Ci/mu-mol at EOB were obtained. Chiral HPLC peak assignment for the resolved enantiomers was achieved by using two independent methods: polarimetric determination and reaction with dopamine beta-hydroxylase. Positron emission tomography (PET) studies with racemic 6-[F-18]FNE show high uptake and retention in the baboon heart. This work demonstrates that nucleophilic aromatic substitution by [F-18]fluoride ion is applicable to systems having electron-rich aromatic rings, leading to high specific activity radiopharmaceuticals. Furthermore, the suitably protected dihydroxynitrobenzaldehyde 1 may serve as a useful synthetic precursor for the radiosynthesis of other complex F-18-labeled radiotracers. RP BROOKHAVEN NATL LAB, DEPT CHEM, UPTON, NY 11973 USA. FU NINDS NIH HHS [NS-15380] NR 30 TC 50 Z9 51 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-2623 EI 1520-4804 J9 J MED CHEM JI J. Med. Chem. PD FEB PY 1991 VL 34 IS 2 BP 767 EP 771 DI 10.1021/jm00106a043 PG 5 WC Chemistry, Medicinal SC Pharmacology & Pharmacy GA EX563 UT WOS:A1991EX56300043 PM 1995899 ER PT J AU DING, YS FOWLER, JS GATLEY, SJ DEWEY, SL WOLF, AP SCHLYER, DJ AF DING, YS FOWLER, JS GATLEY, SJ DEWEY, SL WOLF, AP SCHLYER, DJ TI SYNTHESIS OF HIGH SPECIFIC ACTIVITY 6-[F-18]FLUORODOPAMINE FOR POSITRON EMISSION TOMOGRAPHY STUDIES OF SYMPATHETIC NERVOUS-TISSUE SO JOURNAL OF MEDICINAL CHEMISTRY LA English DT Note ID CONGESTIVE CARDIOMYOPATHY; HEART RP DING, YS (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. FU NINDS NIH HHS [NS-15380] NR 16 TC 42 Z9 42 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0022-2623 J9 J MED CHEM JI J. Med. Chem. PD FEB PY 1991 VL 34 IS 2 BP 861 EP 863 DI 10.1021/jm00106a055 PG 3 WC Chemistry, Medicinal SC Pharmacology & Pharmacy GA EX563 UT WOS:A1991EX56300055 PM 1995910 ER PT J AU JOY, DC AF JOY, DC TI CONTRAST IN HIGH-RESOLUTION SCANNING ELECTRON-MICROSCOPE IMAGES SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE ELECTRON SOLID INTERACTIONS; MONTE-CARLO SIMULATIONS; LOCALIZATION; METAL COATINGS ID LOW-ENERGY ELECTRONS; STOPPING POWER AB Current scanning electron microscopes, equipped with field emission guns and high-performance immersion lenses, can achieve spatial resolutions of the order of 1 nm in both secondary and backscattered imaging modes over a wide range of operating energies. The generation and interpretation of images with nanometre-scale resolution relies on a detailed knowledge, and application, of electron-solid interactions. This paper develops the practical steps required to produce a high-resolution image, and discusses the principles which govern image interpretation. Attention is focused primarily on materials which are low in atomic number and density, such as biological tissue, but the results apply after appropriate scaling of the physical parameters to most other materials. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. RP JOY, DC (reprint author), UNIV TENNESSEE,KNOXVILLE,TN 37996, USA. NR 11 TC 28 Z9 29 U1 0 U2 2 PU BLACKWELL SCIENCE LTD PI OXFORD PA OSNEY MEAD, OXFORD, OXON, ENGLAND OX2 0EL SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD FEB PY 1991 VL 161 BP 343 EP 355 PN 2 PG 13 WC Microscopy SC Microscopy GA FC296 UT WOS:A1991FC29600013 ER PT J AU AZUMA, Y CHILDS, WJ MENNINGEN, KL AF AZUMA, Y CHILDS, WJ MENNINGEN, KL TI DOPPLER-FREE LASER SPECTROSCOPY OF CEF AND OBSERVATION OF HYPERFINE-STRUCTURE SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article RP AZUMA, Y (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 10 TC 14 Z9 14 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 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD FEB PY 1991 VL 145 IS 2 BP 413 EP 419 DI 10.1016/0022-2852(91)90128-W PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA EV389 UT WOS:A1991EV38900020 ER PT J AU WARPINSKI, NR AF WARPINSKI, NR TI HYDRAULIC FRACTURING IN TIGHT, FISSURED MEDIA SO JOURNAL OF PETROLEUM TECHNOLOGY LA English DT Article AB Large volumes of natural gas are found in tight, fissured reservoirs. Hydraulic fracturing can enhance recovery, but many complications, such as pressure-sensitive or accelerated leakoff, damage, and complex fracturing, arise during treatment of such reservoirs. Special procedures generally should be considered during breakdown and fracturing of these reservoirs. In addition, the use of alternative stimulation strategies may be beneficial. RP WARPINSKI, NR (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 59 TC 27 Z9 31 U1 0 U2 11 PU SOC PETROLEUM ENG PI RICHARDSON PA 222 PALISADES CREEK DR, RICHARDSON, TX 75080 SN 0149-2136 J9 J PETROL TECHNOL JI J. Pet. Technol. PD FEB PY 1991 VL 43 IS 2 BP 146 EP & PG 0 WC Energy & Fuels; Engineering, Chemical; Engineering, Petroleum; Geosciences, Multidisciplinary SC Energy & Fuels; Engineering; Geology GA EW982 UT WOS:A1991EW98200004 ER PT J AU HETRICK, DM JARABEK, AM TRAVIS, CC AF HETRICK, DM JARABEK, AM TRAVIS, CC TI SENSITIVITY ANALYSIS FOR PHYSIOLOGICALLY BASED PHARMACOKINETIC MODELS SO JOURNAL OF PHARMACOKINETICS AND BIOPHARMACEUTICS LA English DT Article DE PHARMACOKINETIC MODELS; SENSITIVITY; MONTE-CARLO; STYRENE; METHYLCHLOROFORM; METHYLENE CHLORIDE; MICHAELIS-MENTEN PARAMETERS ID STREAM ECOSYSTEM MODEL; ERROR ANALYSIS; RATS; EXTRAPOLATIONS; STYRENE AB The present study evaluates the sensitivity of pharmacokinetic model output to variability in the biochemical and metabolic input parameters. Pharmacokinetic models of three chemicals are chosen for analysis: styrene, methylchloroform, and methylene chloride. Results show that model sensitivities are time-, dose-, and species-dependent and that the most sensitive parameters are the maximum Michaelis-Menten metabolism rate V(max) and the blood/air and fat/air partition coefficients. For humans, the muscle/air partition coefficient is also important. Model output is insensitive to the Michaelis-Menten parameter K(m) (except for low doses) and to other tissue/air partition coefficients. C1 US EPA,RES TRIANGLE PK,NC 27711. OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37831. RP HETRICK, DM (reprint author), OAK RIDGE NATL LAB,DIV COMP & TELECOMMUN,POB 2008,OAK RIDGE,TN 37831, USA. NR 15 TC 40 Z9 40 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0090-466X J9 J PHARMACOKINET BIOP JI J. Pharmacokinet. Biopharm. PD FEB PY 1991 VL 19 IS 1 BP 1 EP 20 PG 20 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA EW201 UT WOS:A1991EW20100001 PM 2023106 ER PT J AU FALKOWSKI, PG LAROCHE, J AF FALKOWSKI, PG LAROCHE, J TI ACCLIMATION TO SPECTRAL IRRADIANCE IN ALGAE SO JOURNAL OF PHYCOLOGY LA English DT Review ID MARINE PLANKTONIC DIATOM; DUNALIELLA-TERTIOLECTA CHLOROPHYCEAE; STEADY-STATE PHOTOSYNTHESIS; ULVA-ROTUNDATA CHLOROPHYTA; GROWTH-IRRADIANCE; LIGHT-INTENSITY; PHOTOSYSTEM-II; SKELETONEMA-COSTATUM; ECOTYPIC DIFFERENTIATION; PHYSIOLOGICAL-RESPONSES RP FALKOWSKI, PG (reprint author), BROOKHAVEN NATL LAB, DIV OCEANOGR & ATMOSPHER SCI, UPTON, NY 11973 USA. RI LaRoche, Julie/A-1109-2010 NR 75 TC 443 Z9 455 U1 9 U2 108 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0022-3646 EI 1529-8817 J9 J PHYCOL JI J. Phycol. PD FEB PY 1991 VL 27 IS 1 BP 8 EP 14 DI 10.1111/j.0022-3646.1991.00008.x PG 7 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA EY976 UT WOS:A1991EY97600002 ER PT J AU STEINMAN, AD AF STEINMAN, AD TI EFFECTS OF HERBIVORE SIZE AND HUNGER LEVEL ON PERIPHYTON COMMUNITIES SO JOURNAL OF PHYCOLOGY LA English DT Article DE COCCONEIS; COMPETITION; ELIMIA; GROWTH FORM; HERBIVORY; PERIPHYTON; SNAILS; STIGEOCLONIUM; STREAMS ID PHYTOPLANKTON COMMUNITY; CADDISFLY POPULATION; STREAM; COMPETITION; INSECT AB The effects of herbivore size and hunger level were tested on lotic periphyton community structure and ash-free dry mass(AFDM). My hypotheses were 1) that small herbivores would remove more periphyton per units biomass than large herbivores of the same species because of energetic demands and 2) that within the same size class, starved herbivores would remove more periphyton than nonstarved herbivores. The herbivore used was the prosobranch snail Elima clavaeformis Lea. Seven treatments were employed: 1) no snails (control); 2) small "starved" snails; 3) large "starved" snails; 4) small and large "starved" snails; 5) small fed snails; 6) large fed snails; and 7) small and large fed snails. Although snails removed significant amounts of periphyton AFDM relative to controls, neither snail size nor degree of starvation had a significant effect on loss of total AFDM. Small snails removed significantly more erect forms of Stigeoclonium tenue (C. A. Ag.) Kutz. than large snails, but snail size had no other significant effect. Starved snails removed significantly more Cocconeis placentula Ehr. than fed snails, suggesting that after the more susceptible growth forms (e.g. erect Stigeoclonium) were removed, Cocconeis cells became more vulnerable to grazing by hungry snails. When small and large snails were combined in chambers, large snails gained weight over time, whereas small snails lost weight. These results suggest that intraspecific competition may occur within populations of Elimia. RP OAK RIDGE NATL LAB, DIV ENVIRONM SCI, POB 2008, BLDG 1504, OAK RIDGE, TN 37831 USA. OI Steinman, Alan/0000-0002-4886-4305 NR 33 TC 17 Z9 18 U1 0 U2 3 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0022-3646 EI 1529-8817 J9 J PHYCOL JI J. Phycol. PD FEB PY 1991 VL 27 IS 1 BP 54 EP 59 DI 10.1111/j.0022-3646.1991.00054.x PG 6 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA EY976 UT WOS:A1991EY97600009 ER PT J AU BU, HS PANG, YW SONG, DD YU, TY VOLL, TM CZORNYJ, G WUNDERLICH, B AF BU, HS PANG, YW SONG, DD YU, TY VOLL, TM CZORNYJ, G WUNDERLICH, B TI SINGLE-MOLECULE SINGLE-CRYSTALS SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article ID EXTENDED-CHAIN CRYSTALS; SEGREGATION; NUCLEATION; MELT; POLYETHYLENE; PRESSURE AB Various approaches to the preparation and verification of single-molecule single crystals are discussed for polyethylene and poly(oxyethylene). Analytic tools are electron microscopy, electron diffraction, and differential scanning calorimetry. The main difficulty in producing a single-molecule single crystal is to keep crystals from joining during growth. C1 UNIV TENNESSEE,DEPT CHEM,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. RP BU, HS (reprint author), FUDAN UNIV,DEPT MAT SCI,SHANGHAI,PEOPLES R CHINA. NR 55 TC 51 Z9 60 U1 0 U2 8 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD FEB PY 1991 VL 29 IS 2 BP 139 EP 152 DI 10.1002/polb.1991.090290201 PG 14 WC Polymer Science SC Polymer Science GA EW670 UT WOS:A1991EW67000001 ER PT J AU GURLEY, LR VALDEZ, JG SPALL, WD SMITH, BF GILLETTE, DD AF GURLEY, LR VALDEZ, JG SPALL, WD SMITH, BF GILLETTE, DD TI PROTEINS IN THE FOSSIL BONE OF THE DINOSAUR, SEISMOSAURUS SO JOURNAL OF PROTEIN CHEMISTRY LA English DT Article DE FOSSIL PROTEINS; DINOSAUR PROTEINS; SEISMOSAURUS; BIOMARKERS, FOSSIL COLLAGEN; FOSSIL AMINO ACIDS ID BEHAVIOR; COLLAGEN; SYSTEM AB Proteins have been successfully extracted from the fossil vertebra of a 150-million-year-old sauropod dinosaur ("Seismosaurus") recently excavated from the Morrison Formation of New Mexico. HCl and guanidine.HCl extracts of the fossil bone and its sandstone matrix were concentrated, demineralized, and resolved into a number of different protein fractions by reversed-phase high-performance liquid chromatography (HPLC). One of these fractions had the same retention time as collagen. Amino acid analysis (Pico-Tag method) of these fractions confirmed they were proteins. Comparison of the correlation coefficients of the amino acid analyses with that of collagen standards indicated that none of the fractions contained significant amounts of collagen. Similar HPLC profiles were obtained for the HCl extracts of fossil bone and its sandstone matrix suggesting they contained the same proteins. However, different HPLC profiles were obtained when these HCl extracts were dried and reextracted with guanidine.HCl. These different fractions represent proteins unique to the fossil and were not found in the sandstone matrix. These differences were confirmed by amino acid analysis. Such information on fossil bone proteins might provide useful knowledge concerning the evolution of skeletal molecules and the fossilization process. Similar information on the proteins from the geological matrix might provide useful fingerprints for reconstructing ancient environments and for assessing sedimentary rocks for fossil fuel exploration. C1 SW PALEONTOL FDN INC, ALBUQUERQUE, NM 87106 USA. UNIV CALIF LOS ALAMOS SCI LAB, DIV CHEM & LASER SCI, LOS ALAMOS, NM 87545 USA. RP GURLEY, LR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB, DIV LIFE SCI, MAIL STOP M880, LOS ALAMOS, NM 87545 USA. NR 40 TC 33 Z9 33 U1 0 U2 9 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0277-8033 J9 J PROTEIN CHEM JI J. Protein Chem. PD FEB PY 1991 VL 10 IS 1 BP 75 EP 90 DI 10.1007/BF01024658 PG 16 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA FG061 UT WOS:A1991FG06100009 PM 2054066 ER PT J AU MEI, VC AF MEI, VC TI HEAT-TRANSFER OF BURIED PIPE FOR HEAT-PUMP APPLICATION SO JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article AB It is generally felt that the application of line source theory for ground coil design usually resulted in excessive overdesign. It was anticipated that in order for the ground coil heat pump systems to be economically competitive with other residential heating and cooling systems, ground coil overdesign had to be kept to a minimum. A new ground coil model was derived, which based on energy balance rather than the traditional line source theory. It was aimed to more accurately predict the operation of ground coils. It is the intention of this study to compare this ground coil model with models based on line source theory, a simple line source model and a modified line source model, by using them to simulate the same field test data for both summer and winter ground coil operations. The results indicated that for winter coil operation, the new model predicted the coil liquid exit temperature less than 2-degrees-C maximum deviation from the measured values, with an average deviation less than 1-degrees-C. The modified line source model had an average deviation of more than 1.5-degrees-C. For summer operation, all models underpredicted the measured soil temperatures because the effect of thermal backfill material was not included in the models. The new model still predicted the test results better than the other two models. However, when the effect of sand thermal backfill was included in the new model, which was not easy for the other two models, the calculated soil temperatures were almost identical to the test results. C1 OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831. NR 12 TC 12 Z9 14 U1 1 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0199-6231 J9 J SOL ENERG-T ASME JI J. Sol. Energy Eng. Trans.-ASME PD FEB PY 1991 VL 113 IS 1 BP 51 EP 55 DI 10.1115/1.2929951 PG 5 WC Energy & Fuels; Engineering, Mechanical SC Energy & Fuels; Engineering GA HP744 UT WOS:A1991HP74400008 ER PT J AU KIM, JS LEE, JY SWINNEA, JS STEINFINK, H REIFF, WM LIGHTFOOT, P PEI, S JORGENSEN, JD AF KIM, JS LEE, JY SWINNEA, JS STEINFINK, H REIFF, WM LIGHTFOOT, P PEI, S JORGENSEN, JD TI CRYSTAL-STRUCTURE AND MOSSBAUER-SPECTROSCOPY OF Y2SRFECUO6.5, A DOUBLE-LAYER PEROVSKITE INTERGROWTH PHASE SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID NEUTRON C1 UNIV TEXAS, DEPT CHEM ENGN, AUSTIN, TX 78712 USA. NORTHEASTERN UNIV, DEPT CHEM, BOSTON, MA 02115 USA. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. NR 22 TC 23 Z9 23 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 EI 1095-726X J9 J SOLID STATE CHEM JI J. Solid State Chem. PD FEB PY 1991 VL 90 IS 2 BP 331 EP 343 DI 10.1016/0022-4596(91)90150-G PG 13 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA EW548 UT WOS:A1991EW54800018 ER PT J AU LLOYD, S ZUREK, WH AF LLOYD, S ZUREK, WH TI ALGORITHMIC TREATMENT OF THE SPIN-ECHO EFFECT SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE SPIN-ECHO EFFECT; ALGORITHMIC COMPLEXITY; 2ND LAW OF THERMODYNAMICS ID 2ND LAW; INFORMATION; COMPUTATION; THERMODYNAMICS; RANDOMNESS; SYSTEMS; ENTROPY AB We analyze the apparent increase in entropy in the course of the spin-echo effect using algorithmic information theory. We show that although the state of the spins quickly becomes algorithmically complex, then simple again during the echo, the overall complexity of spins together with the magnetic field grows slowly, as the logarithm of the elapsed time. This slow increase in complexity is reflected in an increased difficulty in taking advantage of the echo pulse. Our discussion illustrates the fundamental role of algorithmic information content in the formulation of statistical physics, including the second law of thermo-dynamics, from the viewpoint of the observer. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP LLOYD, S (reprint author), CALTECH,PASADENA,CA 91125, USA. NR 29 TC 8 Z9 8 U1 1 U2 2 PU PLENUM PUBL CORP PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD FEB PY 1991 VL 62 IS 3-4 BP 819 EP 839 DI 10.1007/BF01017985 PG 21 WC Physics, Mathematical SC Physics GA FD562 UT WOS:A1991FD56200016 ER PT J AU JOHNSON, PA MIGLIORI, A SHANKLAND, TJ AF JOHNSON, PA MIGLIORI, A SHANKLAND, TJ TI CONTINUOUS WAVE PHASE DETECTION FOR PROBING NONLINEAR ELASTIC WAVE INTERACTIONS IN ROCKS SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB A new method that uses nonlinear elastic wave generation to produce a continuous wave (cw) phase measurement from which dimensions or velocities of a body can be obtained is described. Like the technique of standing wave resonance for obtaining sound velocities, this method takes advantage of the high accuracy characteristic of frequency measurements. In the experiment, two intersecting, high-frequency primary signals f1 and f2 are mixed inside a sample, creating a directional beam at the difference frequency DELTA-f = f1 - f2. An externally generated, low-pass-filtered DELTA-f signal is electronically mixed with the signal obtained from the sample. As either primary frequency is swept, the dc component from the mixer varies between relative maximum and minimum values at characteristic frequency intervals depending on the phase differences. The resulting interference signal can be used to calculate the distance from the mixing volume in the sample to the detector and to the two primary signal transmitters, providing that a single characteristic distance and wave velocities are known. The reverse experiment is determining velocities from known dimensions. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545. RP JOHNSON, PA (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV EARTH & ENVIRNM SCI,MAIL STOP D443,LOS ALAMOS,NM 87545, USA. NR 7 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD FEB PY 1991 VL 89 IS 2 BP 598 EP 603 DI 10.1121/1.400384 PG 6 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA EX020 UT WOS:A1991EX02000012 ER PT J AU BECHER, PF AF BECHER, PF TI MICROSTRUCTURAL DESIGN OF TOUGHENED CERAMICS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 92ND ANNUAL MEETING OF THE AMERICAN CERAMIC SOC CY APR 26, 1990 CL DALLAS, TX SP AMER CERAM SOC ID FRACTURE-RESISTANCE MECHANISM; CRACK DEFLECTION PROCESSES; MATRIX COMPOSITES; REINFORCED CERAMICS; BRITTLE MATERIALS; GRAIN-SIZE; TOUGHNESS; TRANSFORMATION; BEHAVIOR; ALUMINA AB The fracture toughness of ceramics can be improved by the incorporation of a variety of discontinuous, elastic reinforcing phases that generate a crack-bridging zone. Recent models of toughening by crack-bridging processes are discussed and used to describe the behavior observed in whisker-reinforced ceramics. The toughening response in ceramics reinforced with other types of discontinuous reinforcements is then considered (e.g., matrix and second-phase platelike grains, elongated matrix grains, and grain-size effects in non-cubic matrices). It is shown that crack-bridging toughening processes can be combined with other bridging mechanisms and with other toughening mechanisms (e.g., transformation toughening) to achieve synergistic effects. From these discussions, it is shown that the design of the toughened materials relies heavily on the control of the material properties and microstructural components influencing the toughening behavior to optimize the contributions of both the reinforcing phase and the matrix. RP BECHER, PF (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831, USA. NR 74 TC 706 Z9 734 U1 9 U2 137 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 1991 VL 74 IS 2 BP 255 EP 269 DI 10.1111/j.1151-2916.1991.tb06872.x PG 15 WC Materials Science, Ceramics SC Materials Science GA EX751 UT WOS:A1991EX75100001 ER PT J AU HANIGOFSKY, JA MORE, KL LACKEY, WJ LEE, WY FREEMAN, GB AF HANIGOFSKY, JA MORE, KL LACKEY, WJ LEE, WY FREEMAN, GB TI COMPOSITION AND MICROSTRUCTURE OF CHEMICALLY VAPOR-DEPOSITED BORON-NITRIDE, ALUMINUM NITRIDE, AND BORON-NITRIDE + ALUMINUM NITRIDE COMPOSITES SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article DE CHEMICAL VAPOR DEPOSITION; ALUMINUM NITRIDE; BORON NITRIDE; MICROSTRUCTURE; COMPOSITES ID FILMS AB The composition and microstructure of dispersed-phase ceramic composites containing BN and AIN as well as BN and AIN single-phase ceramics prepared by chemical vapor deposition have been characterized using X-ray diffraction, scanning electron microscopy, electron microprobe, and transmission electron microscopy techniques. Under certain processing conditions, the codeposited coating microstructure consists of small single-crystal AIN fibers (whiskers) surrounded by a turbostratic BN matrix. Other processing conditions resulted in single-phase films of AIN with a fibrous structure. The compositions of the codeposits range from 2 to 50 mol% BN, 50 to 80 mol% AIN with 7% to 25% oxygen impurity as determined by electron microprobe analysis. C1 GEORGIA INST TECHNOL,GEORGIA TECH RES INST,SCH CHEM ENGN,ATLANTA,GA 30332. OAK RIDGE NATL LAB,HIGH TEMP MAT LAB,OAK RIDGE,TN 37831. RP HANIGOFSKY, JA (reprint author), GEORGIA INST TECHNOL,GEORGIA TECH RES INST,SCH MAT ENGN,ATLANTA,GA 30332, USA. RI More, Karren/A-8097-2016 OI More, Karren/0000-0001-5223-9097 NR 17 TC 16 Z9 16 U1 2 U2 5 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 1991 VL 74 IS 2 BP 301 EP 305 DI 10.1111/j.1151-2916.1991.tb06879.x PG 5 WC Materials Science, Ceramics SC Materials Science GA EX751 UT WOS:A1991EX75100008 ER PT J AU MAYA, L RICHARDS, HL AF MAYA, L RICHARDS, HL TI POLYMERIC CYANOBORANE, (CNBH2)N - SINGLE SOURCE FOR CHEMICAL VAPOR-DEPOSITION OF BORON-NITRIDE FILMS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article DE CHEMICAL VAPOR DEPOSITION; FILMS; BORANES; POLYMERS; AMMONIA ID THIN-FILMS; PYROLYSIS AB Polymeric cyanoborane, (CNBH2)n, is a material readily prepared by passing hydrogen chloride through an ether suspension of sodium cyanotrihydroborate. This polymeric material was volatilized in a CVD reactor to produce, at 600-degrees-C, amorphous films containing boron, nitrogen, and carbon. Residual carbon present in the films was removed by ammonia treatment at 800-degrees-C, producing nearly stoichiometric boron nitride films that were adherent to a variety of substrates including silicon. C1 OAK RIDGE NATL LAB,DEV SECT,Y-12 PLANT,OAK RIDGE,TN 37831. RP MAYA, L (reprint author), OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831, USA. NR 11 TC 20 Z9 20 U1 0 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 1991 VL 74 IS 2 BP 406 EP 409 DI 10.1111/j.1151-2916.1991.tb06895.x PG 4 WC Materials Science, Ceramics SC Materials Science GA EX751 UT WOS:A1991EX75100024 ER PT J AU RAHAMAN, MN DEJONGHE, LC AF RAHAMAN, MN DEJONGHE, LC TI SINTERING OF CERAMIC PARTICULATE COMPOSITES - EFFECT OF MATRIX DENSITY SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article DE SINTERING; ZINC OXIDE; SILICON CARBIDE; DENSITY; INCLUSIONS ID HETEROGENEOUS POWDER COMPACTS; RIGID INCLUSIONS; STRESSES AB Composites consisting of a fine-grained, polycrystalline zinc oxide matrix and < 10 vol% coarse, rigid silicon carbide inclusions were prepared by the same mixing procedure and then compacted to produce samples with matrix densities of 0.45 and 0.68 of the theoretical. The samples were sintered under identical temperature profiles in separate experiments that employed either a constant rate of heating of 4-degrees-C/min or near isothermal heating at 735-degrees-C. The ratio of the densification rate of the composite matrix to the densification rate of the composite matrix to the densification rate of the unreinforced zinc oxide was found to be independent of the initial matrix density. This ratio increased significantly with temperature in the constant-heating-rate experiments but was relatively constant in the isothermal experiments. The results indicate that microstructural coarsening may be an important mechanism for explaining the reduced sinterability of polycrystalline matrix composites. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94704. RP RAHAMAN, MN (reprint author), UNIV MISSOURI,DEPT CERAM ENGN,ROLLA,MO 65401, USA. NR 14 TC 11 Z9 11 U1 1 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD FEB PY 1991 VL 74 IS 2 BP 433 EP 436 DI 10.1111/j.1151-2916.1991.tb06903.x PG 4 WC Materials Science, Ceramics SC Materials Science GA EX751 UT WOS:A1991EX75100032 ER PT J AU ISAACS, HS DAVENPORT, AJ SHIPLEY, A AF ISAACS, HS DAVENPORT, AJ SHIPLEY, A TI THE ELECTROCHEMICAL RESPONSE OF STEEL TO THE PRESENCE OF DISSOLVED CERIUM SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID CORROSION; PROTECTION; CHLORIDE AB A vibrating probe technique for measuring the current density distribution over a corroding steel surface has been used to investigate corrosion inhibition by cerium salts. The probe vibrations enabled the current magnitude and direction in a plane perpendicular to the steel surface to be measured. Contrary to published data, it has been concluded that, at least for steels, cerium acts as an anodic inhibitor. C1 MARINE BIOL LAB,WOODS HOLE,MA 02543. RP ISAACS, HS (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. RI Davenport, Alison/J-6089-2013 OI Davenport, Alison/0000-0003-0853-515X NR 15 TC 37 Z9 39 U1 0 U2 4 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD FEB PY 1991 VL 138 IS 2 BP 390 EP 393 DI 10.1149/1.2085595 PG 4 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA EV776 UT WOS:A1991EV77600008 ER PT J AU FRANKEL, GS RUSH, BM JAHNES, CV FARRELL, CE DAVENPORT, AJ ISAACS, HS AF FRANKEL, GS RUSH, BM JAHNES, CV FARRELL, CE DAVENPORT, AJ ISAACS, HS TI REPASSIVATION TRANSIENTS MEASURED WITH THIN-FILM BREAKING ELECTRODES SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Note ID GROWTH C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. RP FRANKEL, GS (reprint author), IBM CORP,THOMAS J WATSON RES CTR,DIV RES,YORKTOWN HTS,NY 10598, USA. RI Davenport, Alison/J-6089-2013; Street, Steven/A-5398-2015 OI Davenport, Alison/0000-0003-0853-515X; Street, Steven/0000-0002-8999-3701 NR 10 TC 28 Z9 28 U1 1 U2 2 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD FEB PY 1991 VL 138 IS 2 BP 643 EP 644 DI 10.1149/1.2085652 PG 2 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA EV776 UT WOS:A1991EV77600064 ER PT J AU MCLARNON, FR CAIRNS, EJ AF MCLARNON, FR CAIRNS, EJ TI THE SECONDARY ALKALINE ZINC ELECTRODE SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Review ID AQUEOUS POTASSIUM HYDROXIDE; SOLUBLE BATTERY ELECTRODES; BONDED POROUS-ELECTRODES; ROTATING-DISK ELECTRODE; ZN-KOH SYSTEM; SHAPE CHANGE; CURRENT DISTRIBUTIONS; ZN/NIOOH CELLS; CYCLE-LIFE; REDEPOSITION PROCESSES AB Zinc is the most commonly used battery electrode, and zinc primary batteries have found numerous applications. The zinc electrode is electrochemically reversible in alkaline electrolytes, and there is a strong incentive to develop a practical secondary battery based on this metal. However, secondary batteries that use zinc electrodes typically exhibit short life-times, because of problems with zinc material redistribution and undesirable zinc morphologies that form during recharge. There has been a worldwide effort to develop a long-lived secondary alkaline zinc electrode, and marked improvements in cell lifetimes have resulted. This article reviews these efforts, paying particular attention to research and development during the period 1975-1990. RP MCLARNON, FR (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV APPL SCI,BERKELEY,CA 94720, USA. RI Cairns, Elton/E-8873-2012 OI Cairns, Elton/0000-0002-1179-7591 NR 597 TC 182 Z9 191 U1 13 U2 76 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 10 SOUTH MAIN STREET, PENNINGTON, NJ 08534 SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD FEB PY 1991 VL 138 IS 2 BP 645 EP 664 DI 10.1149/1.2085653 PG 20 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA EV776 UT WOS:A1991EV77600065 ER PT J AU CLARKE, AP SCHWARZ, RB THOMPSON, JD AF CLARKE, AP SCHWARZ, RB THOMPSON, JD TI INTERGRANULAR PHASES IN CYCLICALLY ANNEALED YBA2CU3O7-X - IMPLICATIONS FOR CRITICAL CURRENT DENSITIES SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID MAGNETIC HYSTERESIS; SUPERCONDUCTOR AB We report changes in the intergranular material composition and grain morphology of YBa2Cu3O7-x caused by cyclic anneals between 780 and 980-degrees-C in oxygen at 1 atm. Two endothermic reactions are detected by differential scanning calorimetry (DSC): (a) the eutectic reaction of YBa2Cu3O7-x with CuO and BaCuO2 at 900-degrees-C (reaction enthalpy DELTA-H(a)) and (b) the peritectic reaction of YBa2Cu3O7-x with CuO at 950-degrees-C to form Y2BaCuO5 and liquid (reaction enthalpy DELTA-H(b)). During the first anneal, only reaction (b) is detected. Although reaction (b) should only occur if there is an excess of CuO, its signature is apparent in all published DSC data covering this temperature range. Cyclic annealing causes a monotonic decrease in DELTA-H(b) and an increase in DELTA-H(a). A steady state is reached after 10 cycles at which point DELTA-H(b) = 0. We propose a model that explains the origin of the intergranular CuO and the changes in the intergranular material composition with cyclic annealing. The cyclic annealing causes increases in the average grain size and in the volume fraction of superconducting phase. C1 UNIV CALIF LOS ALAMOS SCI LAB,P-10 GRP,LOS ALAMOS,NM 87545. UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545. NR 26 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 1 EP 17 DI 10.1016/0022-5088(91)90030-8 PG 17 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700002 ER PT J AU HINKS, DG JORGENSEN, JD RICHARDS, DR PEI, SY ZHENG, Y DABROWSKI, B MITCHELL, AW AF HINKS, DG JORGENSEN, JD RICHARDS, DR PEI, SY ZHENG, Y DABROWSKI, B MITCHELL, AW TI CHEMICAL AND CRYSTALLOGRAPHIC PHASE-BEHAVIOR IN THE BA1-XKXBIO3 SYSTEM SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID ELECTRONIC-STRUCTURE; SUPERCONDUCTIVITY; BA2BI3+BI5+O6; BAPB1-XBIXO3 AB The chemical behavior of Ba(1-x)K(x)BiO3-delta at high temperature is investigated. The solubility of potassium in BaBiO3 is a strong function of temperature: as the temperature is increased for superconducting Ba0.6K0.4BiO3 (at constant P(O2)), potassium is initially lost from the lattice and is then reincorporated at higher temperatures. The superconducting, oxygen-stoichiometric compositions are probably metastable under ambient conditions. At room temperature, the oxygen-stoichiometric material undergoes a series of crystallographic phase transitions as the potassium content is increased. These transitions may be though of as the logical removal of both the symmetric breathing mode and the rigid tilt distortions of the BiO6 octahedra. Eventually at x = 0.37, all static distortions are removed and the material becomes cubic and superconducting. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,ARGONNE,IL 60439. RP HINKS, DG (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 12 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 19 EP 29 DI 10.1016/0022-5088(91)90031-X PG 11 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700003 ER PT J AU FISK, Z THOMPSON, JD HUNDLEY, MF SCHWARZ, RB KWEI, GH SCHIRBER, JE CHEONG, SW COOPER, AS BORDET, P MAREZIO, M AF FISK, Z THOMPSON, JD HUNDLEY, MF SCHWARZ, RB KWEI, GH SCHIRBER, JE CHEONG, SW COOPER, AS BORDET, P MAREZIO, M TI PROPERTIES OF T-STAR-PHASE CUPRATE MATERIALS SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID RARE-EARTH; SUPERCONDUCTIVITY; 30-K AB Properties of the hole-type, single-layer cuprate T*-phase superconductors are discussed. There is a strong variation of T(c) with rare-earth constituent and oxygenation pressure. The magnetic properties of these materials have not yet been well investigated, but some aspects of the rare-earth ordering appear to be different from other known cuprates. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. AT&T BELL LABS,MURRAY HILL,NJ 07974. CNRS,CRYSTALLOG LAB,F-38042 GRENOBLE,FRANCE. RP FISK, Z (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 17 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 31 EP 37 DI 10.1016/0022-5088(91)90032-Y PG 7 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700004 ER PT J AU ASTA, M DEFONTAINE, D CEDER, G SALOMONS, E KRAITCHMAN, M AF ASTA, M DEFONTAINE, D CEDER, G SALOMONS, E KRAITCHMAN, M TI ONE-DIMENSIONAL AND 2-DIMENSIONAL OXYGEN ORDERING IN YBA2CU3OZ SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID BA-CU-O; BASAL-PLANE; ELECTRON-MICROSCOPY; PHASE; SUPERCONDUCTOR; TRANSITION; SUPERSTRUCTURES; TEMPERATURE; BEHAVIOR; LATTICES AB It is shown that the (three-dimensional) tetragonal to orthorhombic transition in the 1-2-3 superconducting compound can be mapped onto a two-dimensional Ising model with anisotropic second neighbor effective pair interactions. The cluster variation method (CVM) has been used to calculate a phase diagram based on interaction parameters provided by first principles linear muffin-tin orbital-atomic sphere approximation (LMTO-ASA) calculations performed by P. Sterne at Lawrence Livermore National Laboratory. At high temperature, agreement with experimental phase transition data is excellent. At low temperatures, two-dimensional ordering gives way to quasi one-dimensional states of order as described by the linear chain Ising model for which the thermodynamics are known exactly. Structures produced by Monte Carlo simulation and theoretical diffraction patterns are in striking agreement with recent experimental results. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP ASTA, M (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 43 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 39 EP 51 DI 10.1016/0022-5088(91)90033-Z PG 13 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700005 ER PT J AU MITCHELL, TE ROY, T SATO, H AF MITCHELL, TE ROY, T SATO, H TI STRUCTURAL INSTABILITIES IN SUPERCONDUCTING CUPRATES SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID CA-CU-O; RESOLUTION ELECTRON-MICROSCOPY; MODULATED STRUCTURE; CRYSTAL-STRUCTURE; TL; BA; OXIDES; DIFFRACTION; YBA2CU3OX; PHASE AB Investigations of the crystal chemistry of the family of superconducting cuprates has yielded a rich harvest of crystallographic structures. Further investigation has revealed that many of the structures undergo small distortions which are manifested in a variety of ways. For example, the tetragonal-to-orthorhombic transformations observed in the Y-Ba-Cu-O and La-Sr-Cu-O systems are due respectively to oxygen vacancy ordering and rotation of the CuO6 octahedra. The incommensurate periodicities observed in the Bi-Ca-Sr-Cu-O and Tl-Ba-Ca-Cu-O systems are due to displacements associated with the heavy cations. The commensurate periodicities observed in Gd2CuO4 and other lanthanide cuprates are also probably due to displacements of the rare earth ions. On the other hand, commensurate structures in reduced Y-Ba-Cu-O are due to oxygen vacancy ordering. These various structural instabilities are discussed in terms of structural nuances in the perovskite family. C1 PURDUE UNIV,SCH MAT ENGN,W LAFAYETTE,IN 47907. RP MITCHELL, TE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 36 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 53 EP 67 DI 10.1016/0022-5088(91)90034-2 PG 15 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700006 ER PT J AU DESCH, PB SCHWARZ, RB NASH, P AF DESCH, PB SCHWARZ, RB NASH, P TI FORMATION OF METASTABLE L12 PHASES IN AL3ZR AND AL-12.5-PERCENT-X-25-PERCENT-ZR (X = LI, CR, FE, NI, CU) SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID STRUCTURAL INTERMETALLIC COMPOUNDS; AL-ZR ALLOYS; ALUMINUM AB The intermetallic Al3Zr crystallizes in the tetragonal DO23 structure but can be produced as a metastable cubic L1(2) structure by rapid solidification. We have studied the effects of mechanical alloying, a low-temperature isothermal processing method, and ternary additions of lithium, chromium, iron, nickel and copper on the phase stability of the L1(2) phase. Mechanically alloyed Al3Zr is single-phase L1(2) which is stable up to 550-degrees-C. The additions of lithium or chromium increase the stability of the L1(2) phase to 750 and 740-degrees-C, respectively. The addition of iron or nickel leads to the formation of amorphous, rather than L1(2), phases. Mechanically alloyed Al-12.5%Cu-25%Zr is single-phase L1(2) and this phase is stable up to at least 1300-degrees-C. C1 IIT,DEPT MET & MAT ENGN,CHICAGO,IL 60616. RP DESCH, PB (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 25 TC 32 Z9 33 U1 1 U2 6 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 69 EP 80 DI 10.1016/0022-5088(91)90035-3 PG 12 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700007 ER PT J AU NASTASI, M AF NASTASI, M TI PHASE-STABILITY OF ION IRRADIATED NI2AL3 SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID AL/PT THIN-FILMS; TRANSFORMATION; ALLOYS; AL/NI AB The low-temperature phase stability of thin film Ni2Al3 under 400 keV Kr+ ion irradiation was examined in the Argonne National Laboratory high-voltage electron microscope. At 20 K the disordering transformation from D5(13)-Ni2Al3-to-B2(CsCl)-to-A2(b.c.c.) was observed during an exposure to 7.5 X 10(13) Kr cm-2. A combination of amorphous and b.c.c. phases was observed at 1.5 x 10(14) Kr cm-2 with complete amorphization occurring after 3 x 10(14) Kr cm-2. This transformation sequence is supported by an analysis of quasi-chemical and CALPHAD-type thermodynamic data. The observations and analysis indicate that the free energy of the amorphous state is higher than the free energy of the disordered state and that additional forms of radiation damage besides chemical disordering are required for the amorphization of Ni2Al3. RP NASTASI, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 29 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 91 EP 102 DI 10.1016/0022-5088(91)90037-5 PG 12 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700009 ER PT J AU TURCHI, PEA FINEL, A AF TURCHI, PEA FINEL, A TI PHASE-STABILITY PROPERTIES IN COMPLEX SUBSTITUTIONAL ALLOYS SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID ELECTRONIC-STRUCTURE; ORDERED STRUCTURES; TRANSITION-METALS; GROUND-STATE; DIAGRAMS; LATTICE AB Order-disorder phenomena and structural transformations in substitutional alloys are of great interest in both the theoretical and technological fields of phase stability in general. In this paper, we first briefly review the advanced methodology which has been developed recently to study phase formation. Then we present our results on the effect of a tetragonal distortion of the b.c.c. crystalline structure onto the thermodynamic properties of transition metal alloys. Finally, we discuss our recent predictions pertaining to the possible existence of new ordered states based upon the A15 crystalline structure. C1 OFF NATL ETUD & RECH AEROSP,F-92322 CHATILLON,FRANCE. RP TURCHI, PEA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV CONDENSED MATTER,L-268,POB 808,LIVERMORE,CA 94550, USA. NR 33 TC 0 Z9 0 U1 0 U2 3 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 103 EP 113 DI 10.1016/0022-5088(91)90038-6 PG 11 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700010 ER PT J AU GONIS, A SLUITER, M TURCHI, PEA STOCKS, GM NICHOLSON, DM AF GONIS, A SLUITER, M TURCHI, PEA STOCKS, GM NICHOLSON, DM TI ELECTRONIC-STRUCTURE, ALLOY PHASE-STABILITY AND PHASE-DIAGRAMS SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID TRANSITION-METAL ALLOYS; COHERENT-POTENTIAL APPROXIMATION; GENERALIZED PERTURBATION-THEORY; DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY; SUBSTITUTIONAL ALLOYS; ORDERING ENERGIES; BINARY-ALLOYS; CLUSTER; SYSTEMS AB We review the relevance of electronic structure calculations to the determination of alloy phase stability and alloy phase diagrams. The Connolly-Williams method, the generalized perturbation method, the embedded cluster method and the method of concentration waves are presented and their main features are discussed and compared. The results of calculations of effective cluster interactions in substitutionally disordered alloys and of phase diagrams for specific alloy systems, e.g. PdRh, PdV and AlLi, are shown and work currently in progress is briefly described. C1 OAK RIDGE NATL LAB,MET & CERAM,OAK RIDGE,TN 37831. RP GONIS, A (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,CHEM & MAT SCI,L-268,LIVERMORE,CA 94550, USA. RI Sluiter, Marcel/E-6086-2010; Stocks, George Malcollm/Q-1251-2016 OI Sluiter, Marcel/0000-0002-6514-4318; Stocks, George Malcollm/0000-0002-9013-260X NR 48 TC 9 Z9 9 U1 0 U2 2 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 127 EP 144 DI 10.1016/0022-5088(91)90040-B PG 18 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700012 ER PT J AU CHANDRA, D DING, W LYNCH, RA TOMILINSON, JJ AF CHANDRA, D DING, W LYNCH, RA TOMILINSON, JJ TI PHASE-TRANSITIONS IN PLASTIC CRYSTALS SO JOURNAL OF THE LESS-COMMON METALS LA English DT Article; Proceedings Paper CT SYMP AT THE 119TH ANNUAL MEETING OF THE METALLURGICAL SOC : THERMODYNAMICS AND PHASE RELATIONS OF EXOTIC MATERIALS CY FEB 19-22, 1990 CL ANAHEIM, CA SP AMER SOC METALS INT, THERMODYNAM ALLOY PHASES COMM, MET SOC ID MIXTURES AB The solid state phase transitions in certain organic molecular plastic crystals reversibly absorb large amounts of heat. These have potential applications for use in thermal energy storage. Pure plastic crystals undergo first order transformations but the binaries exhibit complex behavior. A phase diagram for two energetic materials, 2,2-dimethyl-1,3-propanediol (NPG) and 2-amino-2-methyl-1,3-propanediol (AMPL) plastic crystals is proposed. This diagram was determined by high temperature Guinier X-ray diffraction and differential scanning calorimetric methods. It is found that the AMPL rich binaries supercool and the high temperature phase can be triggered by straining the material to release an estimated amount of 50-53 cal g-1 at room temperature. The structure of the high temperature gamma' phase of AMPL is determined as body centered cubic with a lattice parameter 6.778 angstrom at 92-degrees-C; which is much lower than that of 8.8381 angstrom at 46.5-degrees-C for the face centered cubic gamma-phase of NPG. A eutectoid gamma --> alpha + beta transformation occurs at 20-degrees-C. In the AMPL rich mixtures heat is absorbed in the alpha + gamma and alpha + gamma'-regions over a wide temperature range. An interesting feature is that there are binary equilibria between the gamma and gamma' phases, with molecular rotations. Some rather uncommon thermal contractions with abrupt changes of 28% are observed in gamma and gamma'-phases in heating AMPL-25 mol.% NPG binary mixture. C1 MARTIN MARIETTA ENERGY SYST INC,OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP CHANDRA, D (reprint author), UNIV NEVADA,DEPT CHEM & MET ENGN,RENO,NV 89557, USA. NR 16 TC 24 Z9 24 U1 4 U2 11 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-5088 J9 J LESS-COMMON MET PD FEB PY 1991 VL 168 IS 1 BP 159 EP 167 DI 10.1016/0022-5088(91)90042-3 PG 9 WC Chemistry, Physical; Metallurgy & Metallurgical Engineering SC Chemistry; Metallurgy & Metallurgical Engineering GA FC367 UT WOS:A1991FC36700014 ER PT J AU BILBRO, GL SNYDER, WE MANN, RC AF BILBRO, GL SNYDER, WE MANN, RC TI MEAN-FIELD APPROXIMATION MINIMIZES RELATIVE ENTROPY SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID STOCHASTIC RELAXATION; RESTORATION; IMAGES AB We derive the mean-field approximation from the information-theoretic principle of minimum relative entropy instead of by minimizing Peierls's inequality for the Weiss free energy of statistical physics theory. We show that information theory leads to our statistical mechanics procedure. As an example, we consider a problem in binary image restoration. We find that mean-field annealing compares favorably with the stochastic approach. C1 WAKE FOREST UNIV,BOWMAN GRAY SCH MED,DEPT RADIOL,WINSTON SALEM,NC 27103. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP BILBRO, GL (reprint author), N CAROLINA STATE UNIV,CTR COMMUN & SIGNAL PROC,RALEIGH,NC 27695, USA. NR 13 TC 20 Z9 20 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD FEB PY 1991 VL 8 IS 2 BP 290 EP 294 DI 10.1364/JOSAA.8.000290 PG 5 WC Optics SC Optics GA EW646 UT WOS:A1991EW64600006 ER PT J AU KEANE, CJ SUCKEWER, S AF KEANE, CJ SUCKEWER, S TI CALCULATIONS OF SOFT-X-RAY POPULATION INVERSIONS IN RADIATIVELY COOLED CARBON/ALUMINUM PLASMAS SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID STEADY-STATE; AMPLIFICATION; IONS; GAIN; LASERS; COLUMN; POWER; MODEL; LINE AB In this paper radiative cooling as a mechanism for generating soft-x-ray population inversion and gain on the 182-angstrom 3-2 line in C5+ is examined theoretically. A set of rate equations is used to investigate the temporal evaluation of pure-carbon plasmas and carbon plasmas seeded with aluminum as a radiative coolant. In contrast to the results of previous work, relatively low gain is found for the pure-carbon case. The addition of aluminum is shown to increase significantly both the electron cooling rate and the calculated gain on the C VI 182-angstrom line. The results are compared with those obtained by replacing the aluminum with an idealized coolant. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08544. NR 37 TC 10 Z9 10 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD FEB PY 1991 VL 8 IS 2 BP 201 EP 211 DI 10.1364/JOSAB.8.000201 PG 11 WC Optics SC Optics GA EW978 UT WOS:A1991EW97800003 ER PT J AU SRINIVASANRAO, T FISCHER, J TSANG, T AF SRINIVASANRAO, T FISCHER, J TSANG, T TI PICOSECOND FIELD-ASSISTED PHOTOEMISSION FROM YTTRIUM MICROSTRUCTURES SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID PULSE AB We report the in situ formation of nearly periodic microstructures of different grain size by a 266-nm, 10-spec, 10-Hz laser beam with different energies. Photoelectric emission from these surfaces exhibits enhancement of photoelectric quantum efficiency caused by the changes in the work function and optical absorption. Because of the microstructures, the surface field is also enhanced over the applied field, leading to field-assisted photoemission. For the voltages applied in these experiments, the electron yield increases nearly linearly with the applied field, owing to the Schottky effect. A least-squares fit of the data to the theoretical expression for emission under the Schottky effect yields surface field enhancements of 8-15 over the applied field. RP SRINIVASANRAO, T (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 24 TC 7 Z9 7 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD FEB PY 1991 VL 8 IS 2 BP 294 EP 299 DI 10.1364/JOSAB.8.000294 PG 6 WC Optics SC Optics GA EW978 UT WOS:A1991EW97800011 ER PT J AU OLBRIGHT, GR ZIPPERIAN, TE KLEM, J HADLEY, GR AF OLBRIGHT, GR ZIPPERIAN, TE KLEM, J HADLEY, GR TI OPTICAL SWITCHING IN NXN ARRAYS OF INDIVIDUALLY ADDRESSABLE ELECTROABSORPTION MODULATORS BASED ON WANNIER-STARK CARRIER LOCALIZATION IN GAAS/GAALAS SUPERLATTICES SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID ELECTRIC-FIELD; EFFECT DEVICE; ABSORPTION; BISTABILITY; EXCITATION AB We report room- and low-temperature (10-K) electroabsorption measurements in N x N arrays of individually addressable superlattice electroabsorption modulators based on Wannier-Stark carrier localization. Our data exhibit excellent array uniformity over an area encompassing several hundred modulators. We demonstrated electroabsorption changes as large as \DELTA-alpha\ congruent-to 22000 cm-1, electrorefraction changes as large as \DELTA-n\ congruent-to 0.1 (corresponding to a pi/2 phase shift for an congruent-to 2-mu-m-thick superlattice), optical bistability with contrast ratios > 6:1, and relaxation self-oscillations (oscillatory amplitude modulation of an incident cw beam) in an inductive electro-optic circuit. We developed the capability of demonstrating a new electro-optical component technology for integrating two-dimensional source arrays with ultralow-energy optical switching arrays. RP OLBRIGHT, GR (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 17 TC 17 Z9 17 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD FEB PY 1991 VL 8 IS 2 BP 346 EP 354 DI 10.1364/JOSAB.8.000346 PG 9 WC Optics SC Optics GA EW978 UT WOS:A1991EW97800017 ER PT J AU NAKAMURA, Y ICHIGUCHI, K WAKATANI, M JOHNSON, JL AF NAKAMURA, Y ICHIGUCHI, K WAKATANI, M JOHNSON, JL TI STUDY OF MHD EQUILIBRIUM AND STABILITY WITH IMPROVED STELLARATOR EXPANSION APPROACH(STEP CODE) - REPLY SO JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN LA English DT Letter DE PLASMA; HELIOTRON; TORSATRON; STELLARATOR; STELLARATOR EXPANSION; MHD; EQUILIBRIUM; STABILITY; STEP ID PLASMA EQUILIBRIUM C1 PRINCETON UNIV, PLASMA PHYS LAB, PRINCETON, NJ 08543 USA. RP NAKAMURA, Y (reprint author), KYOTO UNIV, PLASMA PHYS LAB, UJI, KYOTO 611, JAPAN. NR 11 TC 0 Z9 0 U1 0 U2 0 PU PHYSICAL SOC JAPAN PI TOKYO PA YUSHIMA URBAN BUILDING 5F, 2-31-22 YUSHIMA, BUNKYO-KU, TOKYO, 113-0034, JAPAN SN 0031-9015 J9 J PHYS SOC JPN JI J. Phys. Soc. Jpn. PD FEB PY 1991 VL 60 IS 2 BP 724 EP 725 DI 10.1143/JPSJ.60.724 PG 2 WC Physics, Multidisciplinary SC Physics GA FD867 UT WOS:A1991FD86700059 ER PT J AU SAEED, M DIMAURO, LF TORNEGARD, S AF SAEED, M DIMAURO, LF TORNEGARD, S TI AMPLIFIER PUMPS ENHANCE ULTRAFAST LASER STUDIES SO LASER FOCUS WORLD LA English DT Article ID REGENERATIVE AMPLIFIER; DYE-LASERS; ND; AMPLIFICATION; OSCILLATOR C1 BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. QUANTRONIX CORP,SMITHTOWN,NY 11787. RP SAEED, M (reprint author), LOUISIANA STATE UNIV,BATON ROUGE,LA 70803, USA. NR 15 TC 4 Z9 4 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD FEB PY 1991 VL 27 IS 2 BP 57 EP & PG 0 WC Optics SC Optics GA EX456 UT WOS:A1991EX45600016 ER PT J AU MCCLURE, ER AF MCCLURE, ER TI MANUFACTURERS TURN PRECISION OPTICS WITH DIAMOND SO LASER FOCUS WORLD LA English DT Article C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,PRECIS ENGN PROGRAM,LIVERMORE,CA 94550. RP MCCLURE, ER (reprint author), MOORE SPECIAL TOOL CO INC,800 UNION AVE,BRIDGEPORT,CT 06607, USA. NR 3 TC 8 Z9 8 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 5TH FLOOR TEN TARA BOULEVARD, NASHUA, NH 03062-2801 SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD FEB PY 1991 VL 27 IS 2 BP 95 EP & PG 0 WC Optics SC Optics GA EX456 UT WOS:A1991EX45600019 ER PT J AU LINDGREN, FT ADAMSON, GL SHORE, VG NELSON, GJ SCHMIDT, PC AF LINDGREN, FT ADAMSON, GL SHORE, VG NELSON, GJ SCHMIDT, PC TI EFFECT OF A SALMON DIET ON THE DISTRIBUTION OF PLASMA-LIPOPROTEINS AND APOLIPOPROTEINS IN NORMOLIPIDEMIC ADULT MEN SO LIPIDS LA English DT Article ID NORMAL POPULATION-SAMPLE; 3 MAJOR COMPONENTS; HYPERLIPIDEMIA; RESOLUTION; HUMANS AB The effects of n-3 fatty acids on plasma lipids, lipoproteins and apoproteins have usually been studied in humans after feeding of purified fish oil. This study describes the effect of a natural diet, containing salmon as the source of n-3 fatty acids, on these parameters as compared to a diet very low in n-3 fatty acids. The subjects were nine normolipidemic, healthy males who were confined to a nutrition suite for 100 days. During the first 20 days of the study the participants were given a stabilization diet consisting of 55% carbohydrates, 15% protein, and 30% fat. The n-3 content of this diet was less than 1%, and it contained no 20- or 22-carbon n-3 fatty acids. After the stabilization period the men were split into two groups, one group continued on the stabilization diet while the other received the salmon diet that contained approximately 2.1 energy percent (En%) of calories from 20- and 22-carbon n-3 fatty acids. Both diets contained equal amounts of n-6 fatty acids. This regime continued for 40 days, then the two groups switched diets for the remainder of the study. Plasma triglycerides were lowered significantly (p < 0.01) and high density lipoprotein cholesterol (HDL-C) was significantly elevated (p < 0.01) after the men consumed the salmon diet for 40 days. The very low density lipoproteins (VLDL) were lowered, but the trend did not reach statistical significance during the intervention period. The total plasma cholesterol, total low density lipoprotein (LDL) and the total high density lipoprotein (HDL) levels were not influenced by the salmon diet. Within the HDL fraction, however, the larger HDL2 subfractions were significantly elevated (p < 0.002), and the smaller, more dense HDL3 was lowered (p < 0.002) by the salmon diet. These significant changes were detected by analytic ultracentrifugation and confirmed by gradient gel electrophoresis. Analysis of the apolipoproteins (apo) AI, AII, B, and E, and Lp(a) indicated only significant lowering of apoAI, consistent with the increased HDL2, which is higher in cholesterol but lower in the major HDL apolipoprotein, apoAI. Thus, the purported beneficial cardiovascular effects of consumption of n-3 fatty acids by humans may, in part, be attributable to changes in the HDL distribution, i.e., the lowering of the more dense HDL3 and the elevation of the larger, less dense HDL2. C1 USDA ARS,WESTERN HUMAN NUTR RES CTR,SAN FRANCISCO,CA 94129. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,LIVERMORE,CA 94550. RP LINDGREN, FT (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV RES MED & RADIAT BIOPHYS,BERKELEY,CA 94720, USA. FU NHLBI NIH HHS [HL 18574] NR 24 TC 22 Z9 22 U1 0 U2 1 PU AMER OIL CHEMISTS SOC PI CHAMPAIGN PA 1608 BROADMOOR DRIVE, CHAMPAIGN, IL 61821-0489 SN 0024-4201 J9 LIPIDS JI Lipids PD FEB PY 1991 VL 26 IS 2 BP 97 EP 101 DI 10.1007/BF02544001 PG 5 WC Biochemistry & Molecular Biology; Nutrition & Dietetics SC Biochemistry & Molecular Biology; Nutrition & Dietetics GA EY118 UT WOS:A1991EY11800002 PM 2051900 ER PT J AU BLANK, ML CRESS, EA SMITH, ZL SNYDER, F AF BLANK, ML CRESS, EA SMITH, ZL SNYDER, F TI DIETARY SUPPLEMENTATION WITH ETHER-LINKED LIPIDS AND TISSUE LIPID-COMPOSITION SO LIPIDS LA English DT Note ID PLATELET-ACTIVATING FACTOR; PERFORMANCE LIQUID-CHROMATOGRAPHY; ALKYL; METABOLISM; ANALOG; ALKYLGLYCEROL; ALCOHOLS; GLYCEROL; RATS AB The goal of this investigation was to determine the effect of an alkylglycerol dietary supplement on the lipid composition of several major organs. Lipids from kidney, liver, and lung tissues of rats on a laboratory chow diet (controls) were compared to lipids from the same tissues of rats that had received oral supplements (300-600 mg/day) of 1-OMICRON-alkyl-2,3-diacetyl-sn-glycerol (alkyl groups were 65% 18:1 and 17% 16:1) for six days. Incorporation of the alkylglycerol into tissue lipids was indicated by both the presence of a neutral lipid in liver that had the same chromatographic migration as alkyldiacylglycerols and by a substantial increase (approximately 150% of controls) in the octadecenyl group of the alk-enyl- and alkyl-glycerol side chains derived from total phospholipids of all three tissues. Compared to controls, there was a significant increase in the amount of alkylacylglycerophosphocholine in all three tissues of the alkylglycerol supplemented group. Total lipids, total phospholipid phosphorus, or the distribution of phospholipid classes (except for small differences in lung tissue) were not affected by the dietary supplement. The increase in ether lipids was offset by a corresponding decrease in the diacyl subclass in tissues from animals on the alkyldiacetylglycerol supplement. Our results indicate that the amount of ether-linked glycerolipids in rat tissues can be easily increased with dietary supplements of alkylglycerols. C1 OAK RIDGE ASSOCIATED UNIV,DIV MED SCI,POB 117,OAK RIDGE,TN 37831. FU NHLBI NIH HHS [HL-21709-10]; NIDDK NIH HHS [DK-42804-01A1] NR 23 TC 28 Z9 28 U1 0 U2 0 PU AMER OIL CHEMISTS SOC PI CHAMPAIGN PA 1608 BROADMOOR DRIVE, CHAMPAIGN, IL 61821-0489 SN 0024-4201 J9 LIPIDS JI Lipids PD FEB PY 1991 VL 26 IS 2 BP 166 EP 169 DI 10.1007/BF02544013 PG 4 WC Biochemistry & Molecular Biology; Nutrition & Dietetics SC Biochemistry & Molecular Biology; Nutrition & Dietetics GA EY118 UT WOS:A1991EY11800014 PM 2051899 ER PT J AU FENSKE, GR ERDEMIR, A ERCK, RA CHENG, CC BUSCH, DE LEE, RH NICHOLS, FA AF FENSKE, GR ERDEMIR, A ERCK, RA CHENG, CC BUSCH, DE LEE, RH NICHOLS, FA TI ION-ASSISTED DEPOSITION OF HIGH-TEMPERATURE LUBRICOUS SURFACES SO LUBRICATION ENGINEERING LA English DT Article AB High-temperature lubricous surfaces or surface coatings are required in many applications. This paper describes a relatively new surface modification process termed ion assisted deposition, which is capable of forming lubricous layers that are extremely adherent is capable of forming lubricous layers that are extremely adherent to metallic and ceramic substrates. RP FENSKE, GR (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 0 TC 3 Z9 3 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 838 BUSSE HIGHWAY, PARK RIDGE, IL 60068 SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD FEB PY 1991 VL 47 IS 2 BP 104 EP 111 PG 8 WC Engineering, Mechanical SC Engineering GA EX608 UT WOS:A1991EX60800002 ER PT J AU PEDERSON, LR MAUPIN, GD WEBER, WJ MCREADY, DJ STEPHENS, RW AF PEDERSON, LR MAUPIN, GD WEBER, WJ MCREADY, DJ STEPHENS, RW TI COMBUSTION SYNTHESIS OF YBA2CU3O7-X GLYCINE METAL NITRATE METHOD SO MATERIALS LETTERS LA English DT Article ID PARTICLE AB A combustion synthesis method has been developed to simply and rapidly prepare YBa2Cu3O7-x and YBa2Cu3O7-x/Ag from an aqueous solution of the metal nitrates and glycine. Glycine served both as the fuel for combustion and as a complexant, important to prevent inhomogeneous precipitation of individual components prior to combustion. Ash collected following combustion consisted of well-mixed, soft agglomerates of barium carbonate, yttrium oxide, cupric oxide, and/or copper metal, depending on the ratio of fuel to oxidant. This mixture was calcined at 900-degrees-C for 4 h to convert the product to YBa2Cu3O7-x. Samples sintered at 950-degrees-C for 8 h and annealed in oxygen at 450-degrees-C for a like time showed a T(c) (midpoint) of 92.5 K with a width of 1.4 K and a high degree of phase-purity. This synthesis method is well suited to the preparation of a wide variety of multicomponent ceramics. RP PEDERSON, LR (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. RI Weber, William/A-4177-2008 OI Weber, William/0000-0002-9017-7365 NR 11 TC 100 Z9 100 U1 1 U2 29 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD FEB PY 1991 VL 10 IS 9-10 BP 437 EP 443 DI 10.1016/0167-577X(91)90235-X PG 7 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA FA687 UT WOS:A1991FA68700010 ER PT J AU KEISER, JR RAO, M AF KEISER, JR RAO, M TI RESPONSE OF ALUMINUM-ALLOYS TO PARTICLE IMPACTS SO MATERIALS PERFORMANCE LA English DT Article AB This article addresses the relationship between hardening of a sample impacted by a single particle and hardening in a sample eroded to steady-state conditions by multiple-particle impacts. Some of this information provides insight into ripple formation and propagation. RP KEISER, JR (reprint author), OAK RIDGE NATL LAB,POB 2008,OAK RIDGE,TN 37831, USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 SN 0094-1492 J9 MATER PERFORMANCE JI Mater. Perform. PD FEB PY 1991 VL 30 IS 2 BP 80 EP 83 PG 4 WC Materials Science, Characterization & Testing SC Materials Science GA FG642 UT WOS:A1991FG64200007 ER PT J AU KALLEND, JS KOCKS, UF ROLLETT, AD WENK, HR AF KALLEND, JS KOCKS, UF ROLLETT, AD WENK, HR TI OPERATIONAL TEXTURE ANALYSIS SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID ORIENTATION DISTRIBUTIONS; POLE FIGURES AB A comprehensive overview is presented of the elements that enter quantitative techniques of texture measurement, analysis and representations. There are many potential errors to be corrected and many choices to be made in all these stages, and we present those that we consider most appropriate. They have been implemented in a software package that is available publicly. A number of novel techniques are used including, for example, in the representation of measured textures, both for quantitative visual inspection and for use in the prediction of anisotropic properties. The symmetry of the test sample is allowed to be general, and that of the crystal structure may be as low as trigonal. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. RP KALLEND, JS (reprint author), IIT,CHICAGO,IL 60616, USA. RI Rollett, Anthony/A-4096-2012; Kocks, Fred/E-1159-2011 OI Rollett, Anthony/0000-0003-4445-2191; NR 18 TC 278 Z9 280 U1 1 U2 25 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 PY 1991 VL 132 BP 1 EP 11 DI 10.1016/0921-5093(91)90355-Q PG 11 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA FC381 UT WOS:A1991FC38100001 ER PT J AU TAKEYAMA, M LIU, CT AF TAKEYAMA, M LIU, CT TI MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF LAVES-PHASE ALLOYS BASED ON CR2NB SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article AB Mechanical properties of Laves-phase alloys based on Cr2Nb at temperatures up to 1000-degrees-C were examined and correlated with microstructures and phase relationships. Single-phase Cr2Nb alloys are very hard and brittle at ambient temperatures, indicating the difficulty in generation and glide of dislocations due to the complicated crystal structure (C-15). Examination of the Cr-Cr2Nb two-phase region revealed the following: (a) the hardness decreases with increasing amounts of the soft chromium-rich phase; (b) the eutectic composition has a niobium concentration of 17 at.%, instead of 12 at.% as reported in the currently existing phase diagram; (c) heat treatments produce uniform dispersion of fine Laves-phase precipitates in primary chromium-rich patches for the hypoeutectic alloys, and these particles are very stable even at temperatures above 1000-degrees-C; (d) the soft particles are very effective in preventing crack propagation originating in the brittle Laves-phase matrix, which results in a high yield strength with moderate ducitility up to 1000-degrees-C. These results demonstrate that the introduction of a soft chromium phase has promising effects in improving the mechanical properties of brittle Cr2Nb Laves-phase alloys. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 18 TC 120 Z9 133 U1 0 U2 11 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 PY 1991 VL 132 BP 61 EP 66 DI 10.1016/0921-5093(91)90361-P PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA FC381 UT WOS:A1991FC38100007 ER PT J AU KASSNER, ME NGUYEN, NQ HENSHALL, GA MCQUEEN, HJ AF KASSNER, ME NGUYEN, NQ HENSHALL, GA MCQUEEN, HJ TI THE EFFECTS OF TEMPERATURE AND STRAIN RATE ON EXTENDED DUCTILITY OF ALUMINUM SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID STEADY-STATE FLOW; ELEVATED-TEMPERATURES; INTERMEDIATE TEMPERATURES; SINGLE-CRYSTALS; CREEP FRACTURE; DEFORMATION; MICROSTRUCTURE; EVOLUTION; STRESS AB The torsional ductility of high purity aluminum was measured over a wide range of temperature and strain rate and several trends were observed. At each strain rate the ductility first increases with increasing temperature to a "peak ductility", beyond which it decreases. Dramatic ductilities, of over 90 in some cases, are observed in the vicinity of the peaks. The peak ductility appears to increase with increasing strain rate. Contrary to earlier investigations, the temperature at which the peak ductility is observed increases with increasing strain rate. At temperatures below the peak, as temperature rises, dynamic recovery mitigates internal stresses and may retard crack nucleation to produce improved ductility. Increased strain rate at a given temperature increases the internal stresses and the ductility decreases. At temperatures above the peak, diffusive void formation reduces the ductility. Consequently, increased strain rate raises the amount of torsional strain relative to the increase in cavity growth rate and the ductility increases. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,PHYS MET & JOINING SECT,LIVERMORE,CA 94550. CONCORDIA UNIV,DEPT MECH ENGN,MONTREAL H3G 1M8,QUEBEC,CANADA. RP KASSNER, ME (reprint author), OREGON STATE UNIV,DEPT MECH ENGN,CORVALLIS,OR 97331, USA. NR 26 TC 27 Z9 27 U1 1 U2 3 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 PY 1991 VL 132 BP 97 EP 105 DI 10.1016/0921-5093(91)90366-U PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA FC381 UT WOS:A1991FC38100012 ER PT J AU MAIENSCHEIN, JL BARRY, PE MCMURPHY, F BOWERS, J AF MAIENSCHEIN, JL BARRY, PE MCMURPHY, F BOWERS, J TI SYNTHESIS AND PROPERTIES OF A LOW-DENSITY, HIGH POROSITY LITHIUM-HYDRIDE BERYLLIUM-HYDRIDE FOAM SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article AB We have developed a low density (30-670 kg m-3), high porosity (up to 96%) foam containing lithium hydride (LiH) and amorphous beryllium hydride (BeH2). The composition of the foam can be varied, but the most vigorous foaming reaction is observed with equimolar mixtures of LiH and BeH2. We discuss several ways to synthesize the foam, and report on physical properties such as the density, the open and closed porosity, the pore size distribution, the uniformity of foam density and the foam sensitivity to moisture. Hydrogen and organic contaminants in the BeH2 are evolved during the foaming reaction and apparently provide the force needed to expand the plastic reaction mass into a foam. Simultaneous differential thermal analysis-thermogravimetric analysis show that the reaction is endothermic with very little mass loss. The presence of LiBeH3 as either a reaction intermediate or a final product is suggested by the fact that the most vigorous foaming occurs with equimolar mixtures of LiH and BeH2. This foam may be attractive as the X-ray scattering element in the Thomson scattering polarimeter as proposed for inclusion in the High Throughput X-ray Spectroscopy Space Mission sponsored by the European Scientific Agency. RP MAIENSCHEIN, JL (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 8 TC 4 Z9 4 U1 1 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 PY 1991 VL 132 BP 143 EP 152 DI 10.1016/0921-5093(91)90370-3 PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA FC381 UT WOS:A1991FC38100016 ER PT J AU RADMILOVIC, V THOMAS, G DAS, SK AF RADMILOVIC, V THOMAS, G DAS, SK TI MICROSTRUCTURE OF ALPHA-AL BASE MATRIX AND SIC PARTICULATE COMPOSITES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID REINFORCED ALUMINUM; GRAIN-BOUNDARIES; INTERFACES; CERAMICS AB The microstructures of a high temperature monolithic Al-Fe-V-Si alloy and a metal matrix and SiC particulate composite (MMC) based on this alloy matrix were characterized by conventional and high resolution transmission electron microscopy, microdiffraction and X-ray spectroscopy techniques. Silicide particles of average composition Al13(Fe,V)3Si were present in both of these materials. These particles were unstable under the electron beam at voltages above 200 kV, and exhibited radiation-induced disordering. SiC particulates present in the MMC structure were predominantly of the hexagonal 6H polytype, but the rhombohedral 87R-VII polytype was also observed. A very thin reaction layer was present between the matrix and SiC particles. No segregation of alloying elements such as iron, vanadium, or silicon at the matrix-SiC interface was observed. The second phase present at the alpha-Al-SiC interface was probably a disordered silicide. C1 UNIV CALIF BERKELEY,NATL CTR ELECTRON MICROSCOPY,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. ALLIED SIGNAL INC,MET & CERAM LAB,MORRISTOWN,NJ 07962. UNIV BELGRADE,DEPT MET,YU-11001 BELGRADE,YUGOSLAVIA. RP RADMILOVIC, V (reprint author), UNIV CALIF BERKELEY,DEPT MAT SCI,BERKELEY,CA 94720, USA. NR 27 TC 18 Z9 19 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 PY 1991 VL 132 BP 171 EP 179 DI 10.1016/0921-5093(91)90373-U PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA FC381 UT WOS:A1991FC38100019 ER PT J AU NASTASI, M MAYER, JW AF NASTASI, M MAYER, JW TI THERMODYNAMICS AND KINETICS OF PHASE-TRANSFORMATIONS INDUCED BY ION IRRADIATION SO MATERIALS SCIENCE REPORTS LA English DT Review ID TO-AMORPHOUS TRANSFORMATION; THIN-FILMS; COLLISION CASCADES; METASTABLE PHASE; SOLID-STATE; INTERMETALLIC COMPOUNDS; ALLOYS; STABILITY; AL; AMORPHIZATION AB The thermodynamic and kinetic aspects of ion-irradiation-induced phase transformations in intermetallic compounds are reviewed. The different mechanisms for supplying the thermodynamic driving force for such transformations are discussed. The free energy of an irradiated material can be gradually elevated above that of a metastable state by the accumulation of lattice damage through the production of vacancy-interstitial defects, anti-site defects, and dislocations, or quickly elevated by the formation of a thermal spike in the collision cascade. The final state of the irradiated material will ultimately be determined by kinetic constraints in its transformation to lower-energy metastable and equilibrium states. C1 CORNELL UNIV,DEPT MAT SCI & ENGN,ITHACA,NY 14853. RP NASTASI, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 112 TC 79 Z9 80 U1 0 U2 17 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0920-2307 J9 MATER SCI REP PD FEB PY 1991 VL 6 IS 1 BP 1 EP 51 DI 10.1016/0920-2307(91)90003-6 PG 51 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA FP623 UT WOS:A1991FP62300001 ER PT J AU GROVES, SE AF GROVES, SE TI CHARACTERIZING THE FAILURE OF COMPOSITE STRUCTURES SO MECHANICAL ENGINEERING LA English DT Article RP GROVES, SE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 0 TC 1 Z9 1 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 SN 0025-6501 J9 MECH ENG JI Mech. Eng. PD FEB PY 1991 VL 113 IS 2 BP 57 EP 60 PG 4 WC Engineering, Mechanical SC Engineering GA EW732 UT WOS:A1991EW73200013 ER PT J AU RABIN, BH WRIGHT, RN AF RABIN, BH WRIGHT, RN TI SYNTHESIS OF IRON ALUMINIDES FROM ELEMENTAL POWDERS - REACTION-MECHANISMS AND DENSIFICATION BEHAVIOR SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID TRANSIENT LIQUID-PHASE; ALLOYS; DIFFUSION; PROGRESS; AL AB Pressureless sintering and hot pressing experiments were conducted on elemental powder compacts of Fe-15.8 wt pct Al and Fe-32 wt pct Al, corresponding approximately to the compositions of stoichiometric Fe3Al and FeAl, respectively. Upon heating near the melting point of aluminum, an exothermic reaction was initiated in the compacts, resulting in synthesis of the desired compounds with reaction times on the order of seconds. Thermal analysis and microstructural observations indicate the formation of a transient liquid phase during rapid exothermic compact heating. The mechanisms shown to be responsible for microstructural development include initial compound formation in the solid state, appearance of an aluminum-rich liquid at the aluminum particle sites, iron dissolution accompanied by outward spreading of the liquid, and subsequent precipitation of the iron-rich compounds. Apparent enthalpies of formation, DELTA-H-integral-O(298), estimated from reaction temperature measurements were -18 and -31.8 kJ/mol for Fe3Al and FeAl, respectively. The influences of heating rate, green density, and aluminum particle size on sintered density were studied for pressureless reaction sintering in vacuum. The effects of processing variables on densification were explained as the net result of swelling during heating and subsequent shrinkage due to the transient liquid phase. Near full density Fe3Al and FeAl compounds were obtained through the application of external pressures near 70 MPa during reaction in a hot press. These alloys were partially ordered, chemically homogeneous, and exhibited an equiaxed grain structure with an average grain size below 10-mu-m. The Fe3Al material exhibited significantly higher fracture strength and somewhat lower ductility than coarse-grained wrought material of the same composition. RP RABIN, BH (reprint author), IDAHO NATL ENGN LAB,MAT TECHNOL GRP,IDAHO FALLS,ID 83415, USA. NR 30 TC 87 Z9 96 U1 1 U2 10 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD FEB PY 1991 VL 22 IS 2 BP 277 EP 286 DI 10.1007/BF02656797 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA EX055 UT WOS:A1991EX05500001 ER PT J AU HONG, SI LAIRD, C AF HONG, SI LAIRD, C TI FACETED FATIGUE FRACTURE AND ITS RELATION TO THE CRYSTALLOGRAPHIC SLIP SYSTEMS IN CU-16 AT PCT AL SINGLE-CRYSTALS SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID STAINLESS-STEEL 316L; I CORROSION FATIGUE; CRACK CLOSURE; GROWTH; ALLOY; AMPLITUDE AB In order to explore the relationship between the characteristic linear marks on the fracture surfaces of fatigued planar slip materials and the activity of cross slip and secondary slip systems, fatigued single crystals of Cu-16 at. pct Al alloy with a common single slip orientation were examined by scanning electron microscopy (SEM). This paper documents and explains the fractographic details of stages I and II crack propagations as a function of crack depth, strain amplitude, and loading history in a planar slip metal. The linear marks on the fracture surfaces in stage I for the specimen cycled at low strain amplitude are found mostly parallel to the traces of the cross slip plane, which is the plane on which propagation occurs to link up closely parallel cracks on the primary slip plane. With increase of crack depth, the contribution of conjugate slip for the linking up of parallel primary cracks increases. By geometrical consideration of the secondary slip planes with respect to primary cracks, the cross slip plane was found to be the most favored for the linking up of parallel primary cracks. This linking-up phenomenon produces the dominant fracture surface morphology. The fracture surfaces in the final stages show the typical features of ductile fracture in striations or catastrophic rupture. This result indicates that the observation of crystallographic traces on the fracture surfaces in stages I and II need not be associated with a brittle cleavage mechanism of fatigue fracture. The present authors support a ductile, plastic mechanism of crack propagation in both stages I and II. C1 UNIV PENN,DEPT MAT SCI & ENGN,PHILADELPHIA,PA 19104. RP HONG, SI (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 31 TC 13 Z9 13 U1 0 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD FEB PY 1991 VL 22 IS 2 BP 415 EP 425 DI 10.1007/BF02656809 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA EX055 UT WOS:A1991EX05500013 ER PT J AU TRIVEDI, R SEETHARAMAN, V ESHELMAN, MA AF TRIVEDI, R SEETHARAMAN, V ESHELMAN, MA TI THE EFFECTS OF INTERFACE KINETICS ANISOTROPY ON THE GROWTH DIRECTION OF CELLULAR MICROSTRUCTURES SO METALLURGICAL TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID CELLS AB Directional solidification studies have been carried out in the pivalic acid-ethanol system in which significant anisotropies in interface kinetics and interfacial free energy are present. These anisotropic properties influence the microstructure formation and often lead to the formation of cells and dendrites which are tilted with respect to the heat flow direction. It is shown that dendrites always form in the preferred crystallographic direction, whereas the angle of tilt for cells is governed by the relative effects of heat flow and the anisotropic property of the crystal. This tilt angle for a given crystal orientation is found to increase as the velocity is increased. The angle of tilt reaches its largest value when the cell growth direction coincides with the preferred crystallographic direction, i.e., [001] direction for the cubic pivalic acid crystals. At this point, a transition from cellular to dendritic morphology occurs. The variation in the angle of tilt as a function of velocity is examined for the steady-state cellular structures. These results are then compared with the linear and the weakly nonlinear analyses of the planar interface stability to obtain the magnitude of the kinetic anisotropy effects. It is also shown that the cellular spacings as well as the amplitude of cells alter significantly with the angle of tilt under identical conditions of growth rate, temperature gradient, and composition. C1 UNIVERSAL ENERGY SYST,DAYTON,OH 45432. SWISS FED INST TECHNOL,CH-1015 LAUSANNE,SWITZERLAND. RP TRIVEDI, R (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 10 TC 42 Z9 42 U1 1 U2 11 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2133 J9 METALL TRANS A PD FEB PY 1991 VL 22 IS 2 BP 585 EP 593 DI 10.1007/BF02656826 PG 9 WC Materials Science, Multidisciplinary SC Materials Science GA EX055 UT WOS:A1991EX05500030 ER PT J AU LOGRASSO, TA HELLAWELL, A AF LOGRASSO, TA HELLAWELL, A TI DETERMINATION OF LIQUID DIFFUSION-COEFFICIENTS ALONG A LIQUIDUS PHASE-BOUNDARY SO METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY LA English DT Article AB A method for determination of liquid phase diffusion coefficients along the liquidus curve in a binary alloy is presented. The technique is similar to that proposed by Watson and Hunt[1] but is more applicable to a larger selection of alloy systems. The technique utilizes temperature gradient zone melting (TGZM) to produce compositional adjustments along the length of a stationary sample placed in a temperature gradient. Diffusion coefficients as a function of position and, hence, temperature in the sample are calculated from measurement of the compositional changes occurring during TGZM and the temperature profile in the alloy. Since coefficients can be measured over a wide range of temperatures, the activation energy for diffusion can also be determined. The technique is demonstrated for a Cu-85 wt pct Sn alloy. C1 MICHIGAN TECHNOL UNIV,DEPT MET ENGN,HOUGHTON,MI 49931. RP LOGRASSO, TA (reprint author), IOWA STATE UNIV SCI & TECHNOL,AMES LAB,DIV MET & CERAM,AMES,IA 50011, USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2141 J9 METALL TRANS B PD FEB PY 1991 VL 22 IS 1 BP 21 EP 26 DI 10.1007/BF02672522 PG 6 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA EX437 UT WOS:A1991EX43700003 ER PT J AU CAHILL, AE BURKHART, LE AF CAHILL, AE BURKHART, LE TI CONTINUOUS PRECIPITATION OF URANIUM PEROXIDE FROM HIGH-VANADIUM MILL SOLUTIONS SO METALLURGICAL TRANSACTIONS B-PROCESS METALLURGY LA English DT Note C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM ENGN,AMES,IA 50011. RP CAHILL, AE (reprint author), IOWA STATE UNIV SCI & TECHNOL,USDOE,AMES LAB,AMES,IA 50011, USA. NR 2 TC 1 Z9 1 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 SN 0360-2141 J9 METALL TRANS B PD FEB PY 1991 VL 22 IS 1 BP 135 EP 136 DI 10.1007/BF02672534 PG 2 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA EX437 UT WOS:A1991EX43700015 ER PT J AU RUSSELL, LB HUNSICKER, PR CACHEIRO, NLA GENEROSO, WM AF RUSSELL, LB HUNSICKER, PR CACHEIRO, NLA GENEROSO, WM TI INDUCTION OF SPECIFIC-LOCUS MUTATIONS IN MALE GERM-CELLS OF THE MOUSE BY ACRYLAMIDE MONOMER SO MUTATION RESEARCH LA English DT Article DE ACRYLAMIDE; GERM-CELL MUTATIONS; SPECIFIC-LOCUS MUTATIONS ID MALE-MICE; PROTAMINE; DNA; METHANESULFONATE; BINDING AB Acrylamide monomer (AA), injected into male mice at the maximum tolerated dose of 5 x 50 mg/kg (24-h intervals), significantly increased the specific-locus mutation rate in certain poststem-cell stages of spermatogenesis, but not in spermatogonial stem cells. Germ-cell stages in which the treatment induced dominant lethals - namely, exposed spermatozoa and late spermatids (number of surviving offspring only 3% and 27%, respectively, of those in concurrent controls) - jointly yielded the highest frequency of specific-locus mutations. AA thus conforms to Pattern 1 in our earlier classification of chemicals according to the spermatogenic stage at which they elicit maximum response (Russell et al., 1990). No specific-locus mutations were observed among 17,112 offspring derived from exposed spermatogonial stem cells, a result which rules out (at the 5% significane level) an induced mutation rate greater than 2.3 times the historical control rate. A sustained high productivity in matings made for several months following week 3 indicates that there is no significant spermatogonial killing and that cell selection is presumably not the explanation for the negative result. On the basis of genetic and/or cytogenetic evidence, the mutations induced postmeiotically by AA were 'large lesions' (multi-locus), while one of 2 recovered from exposure of differentiating spermatogonia is probably a small lesion. An earlier survery of mammalian mutagenesis results led us to conclude that, regardless of the classification of a chemical according to the stage at which it elicits its maximum response, the nature of mutations is determined by the germ-cell stage in which they are induced (Russell et al., 1990). The AA results on lesion size and on distribution of mutations among the loci fit the general pattern. RP RUSSELL, LB (reprint author), OAK RIDGE NATL LAB,DIV BIOL,POB 2009,OAK RIDGE,TN 37831, USA. FU NIEHS NIH HHS [222Y01-ES-10067] NR 17 TC 43 Z9 45 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8262 J9 MUTAT RES PD FEB PY 1991 VL 262 IS 2 BP 101 EP 107 DI 10.1016/0165-7992(91)90114-J PG 7 WC Genetics & Heredity; Toxicology SC Genetics & Heredity; Toxicology GA EX963 UT WOS:A1991EX96300004 PM 2000095 ER PT J AU HILL, LJ AF HILL, LJ TI CAN DEVELOPING-COUNTRIES BENEFIT FROM INNOVATIVE PRICING IN THE POWER SECTOR SO NATURAL RESOURCES FORUM LA English DT Article AB This study explores electricity pricing as a demand-side management (DSM) strategy, looking to the developed country experience for insights into the types of approaches currently used, their effects, and the direction in which electricity pricing is headed. The discussion should be especially useful for electric utilities in developing countries that are exploring alternatives to capacity expansion to meet current and future electric power demand. For these electric utilities, demand-side options are especially important under today's conditions in which the capital cost of new generating capacity is increasing rapidly, international funds for expanding power sectors are not expected to be sufficient for meeting projected capacity needs and environmental concerns over fossil fuel emissions have raised new questions about constructing thermal power plants. RP HILL, LJ (reprint author), OAK RIDGE NATL LAB,DIV ENERGY,POB 2008,BLDG 4500-N,MS 6205,OAK RIDGE,TN 37831, USA. NR 20 TC 0 Z9 0 U1 0 U2 3 PU BUTTERWORTH-HEINEMANN LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0165-0203 J9 NAT RESOUR FORUM PD FEB PY 1991 VL 15 IS 1 BP 15 EP 25 PG 11 WC Environmental Sciences; Environmental Studies SC Environmental Sciences & Ecology GA FA090 UT WOS:A1991FA09000002 ER PT J AU LO, EH FABRIKANT, JI LEVY, RP PHILLIPS, MH FRANKEL, KA ALPEN, EL AF LO, EH FABRIKANT, JI LEVY, RP PHILLIPS, MH FRANKEL, KA ALPEN, EL TI AN EXPERIMENTAL COMPARTMENTAL FLOW MODEL FOR ASSESSING THE HEMODYNAMIC-RESPONSE OF INTRACRANIAL ARTERIOVENOUS-MALFORMATIONS TO STEREOTAXIC RADIOSURGERY SO NEUROSURGERY LA English DT Article DE ARTERIOVENOUS MALFORMATION; CEREBRAL HEMODYNAMICS; COMPARTMENTAL FLOW MODEL; REGIONAL CEREBRAL BLOOD FLOW; STEREOTAXIC RADIOSURGERY ID BRAGG PEAK RADIOSURGERY; ACCELERATOR; BRAIN AB Stereotactic radiosurgery has proven to be an effective method of treating selected inaccessible or inoperable arteriovenous malformations (AVMs) of the brain. Radiation-induced obliteration of successfully-treated AVMs, however, occurs only after some latent period after treatment, depending on size, location, and dose. An experimental compartmental flow model is proposed to describe the hemodynamic alterations in the AVM as a result of the pathophysiological changes after radiosurgery, and to analyze temporal alterations in AVM blood flow rates and pressure gradients before complete obliteration. In representative small (low-flow, 150 ml/min) and large (high-flow, 440 ml/min) AVMs, it is found that increases in pressure gradients across certain vascular structures within the AVM occur during the normal course of radiation-induced flow decrease and AVM obliteration. The magnitude of these pressure alterations, however, may be within the normal physiological variations in cerebrovascular blood pressure. The effects of partial-volume irradiation of the AVM is examined by limiting radiosurgical treatment to varying portions of the flow compartments within the model. It is found that alterations in pressure gradients persist in unirradiated vascular shunts, even after complete obliteration of the treated AVM volume. These pressure alterations may increase the probability of hemorrhage from the untreated shunts of the AVM and cause redistribution of regional cerebral blood flow resulting in increased flow through these untreated shunts. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV CALIF SAN FRANCISCO,DEPT RADIOL,SAN FRANCISCO,CA 94143. RP LO, EH (reprint author), STANFORD UNIV,MED CTR,SCH MED,DEPT NEUROSURG,S-006,300 PASTEUR DR,STANFORD,CA 94305, USA. NR 31 TC 30 Z9 31 U1 0 U2 0 PU WILLIAMS & WILKINS PI BALTIMORE PA 351 WEST CAMDEN ST, BALTIMORE, MD 21201-2436 SN 0148-396X J9 NEUROSURGERY JI Neurosurgery PD FEB PY 1991 VL 28 IS 2 BP 251 EP 259 PG 9 WC Clinical Neurology; Surgery SC Neurosciences & Neurology; Surgery GA EU430 UT WOS:A1991EU43000012 PM 1997894 ER PT J AU HEAMES, TJ SMITH, RC AF HEAMES, TJ SMITH, RC TI INTEGRATED MELPROG TRAC ANALYSES OF A PWR STATION BLACKOUT SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article ID FLOW AB A complete, coupled, mechanistic analysis of the entire reactor coolant system during a station blackout accident (TMLB') has been completed using the MELPROG/TRAC code. The analysis includes the failure of the seal on all coolant pumps at 100 min into the accident; in all other respects the case is identical to a previous station blackout calculation. Both cases started at accident initiation and continued through boiloff of the water, failure of the control and fuel rods, oxidation of the zircaloy and the formation of U-Zr-O eutectics, failure of the vessel internal structures due to melting and loading, massive core disruption, and subsequent vessel failure. The two cases reached significantly different end conditions. The basic TMLB' resulted in a high pressure (15 MPa) vessel failure approximately 4 h after accident initiation. The addition of a 12.5-mm hole in each pump seal caused the water in the loop seal to clear and resulted in a significantly lower pressure (0.27 MPa) at vessel failure, which occurred almost 10 h after accident initiation. Therefore, high pressure melt ejection (HPME) and the potential for subsequent direct containment heating (DCH) were predicted not to occur in the TMLB' accident scenario with pump seal failure. C1 SANDIA NATL LABS,DIV 6425,ALBUQUERQUE,NM 87185. RP HEAMES, TJ (reprint author), SCI APPLICAT INT CORP,2109 AIR PK RD SE,ALBUQUERQUE,NM 87106, USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD FEB PY 1991 VL 125 IS 2 BP 175 EP 188 DI 10.1016/0029-5493(91)90076-T PG 14 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EZ673 UT WOS:A1991EZ67300007 ER PT J AU YOUNGDAHL, CK AF YOUNGDAHL, CK TI MODAL SOLUTIONS FOR THE DYNAMIC PLASTIC-DEFORMATION OF A BEAM SO NUCLEAR ENGINEERING AND DESIGN LA English DT Article ID PULSE LOADED STRUCTURES; APPROXIMATION TECHNIQUE; SHAPE AB A closed-form solution is derived for the dynamic response of a simply supported rigid-plastic beam subject to a spatially varying time-dependent loading. Two methods are presented for obtaining basic mode approximations that predict exactly the velocity and displacement histories at the beam midpoint. RP YOUNGDAHL, CK (reprint author), ARGONNE NATL LAB,DIV MAT & COMPONENTS TECHNOL,ARGONNE,IL 60439, USA. NR 19 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0029-5493 J9 NUCL ENG DES JI Nucl. Eng. Des. PD FEB PY 1991 VL 125 IS 2 BP 239 EP 250 DI 10.1016/0029-5493(91)90080-2 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EZ673 UT WOS:A1991EZ67300011 ER PT J AU ISLER, RC CRUME, EC HORTON, LD MURAKAMI, M BAYLOR, LR BELL, GL BIGELOW, TS ENGLAND, AC GLOWIENKA, JC JERNIGAN, TC LANGLEY, RA MIODUSZEWSKI, PK RASMUSSEN, DA SIMPKINS, JE WILGEN, JB WING, WR AF ISLER, RC CRUME, EC HORTON, LD MURAKAMI, M BAYLOR, LR BELL, GL BIGELOW, TS ENGLAND, AC GLOWIENKA, JC JERNIGAN, TC LANGLEY, RA MIODUSZEWSKI, PK RASMUSSEN, DA SIMPKINS, JE WILGEN, JB WING, WR TI RADIATIVE LOSSES AND IMPROVEMENT OF PLASMA PARAMETERS AFTER GETTERING IN THE ADVANCED TOROIDAL FACILITY SO NUCLEAR FUSION LA English DT Article ID NEUTRAL-BEAM INJECTION; ISX-B AB The characteristics of plasmas in the Advanced Toroidal Facility (ATF) have proven to be strongly dependent on the type of wall conditioning employed. A succession of techniques, beginning with glow discharge cleaning and baking, and evolving to gettering with chromium and titanium, have led to progressive improvement of the plasma parameters. Gettering with titanium has reduced the low-Z impurity content by a factor of 3, lowered the radiated power by a factor of 2.5-3.5, and improved the control over the electron density. The maximum values achieved for stored energy, line averaged density and confinement times are 28 kJ, 1.2 x 10(14) cm -3 and 25 ms, respectively. These parameters are comparable to the best results achieved in the ISX-B tokamak which had the same average minor radius and one half the major radius of ATF. Quasi-steady operation for 200 ms of neutral beam injection (NBI) has been obtained in high density, titanium gettered plasmas without the collapses that were typical earlier periods of operation. Neon injection experiments have helped to delineate the limits on the global levels of radiation that can be maintained and have supported the conclusion that mechanisms other than radiative losses are important for initiating the collapses still observed in low density NBI plasmas. RP ISLER, RC (reprint author), OAK RIDGE NATL LAB,DIV FUS ENERGY,OAK RIDGE,TN, USA. OI Isler, Ralph/0000-0002-5368-7200 NR 10 TC 14 Z9 14 U1 0 U2 0 PU INT ATOMIC ENERGY AGENCY PI VIENNA PA WAGRAMERSTRASSE 5 PO BOX 100, A-1400 VIENNA, AUSTRIA SN 0029-5515 J9 NUCL FUSION JI Nucl. Fusion PD FEB PY 1991 VL 31 IS 2 BP 245 EP 259 DI 10.1088/0029-5515/31/2/003 PG 15 WC Physics, Fluids & Plasmas SC Physics GA EX598 UT WOS:A1991EX59800003 ER PT J AU KADYK, JA AF KADYK, JA TI WIRE CHAMBER AGING SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID MULTIWIRE PROPORTIONAL CHAMBERS; III VERTEX CHAMBER; DIMETHYL ETHER; FREON CONTENT; GAS-MIXTURES; COUNTERS; LIFETIME; METHANE; ARGON; TMAE AB An overview of wire chamber aging is presented. A history of wire aging studies and the manifestations of wire aging are reviewed. Fundamental chemical principles relating to wire chamber operation are presented, and the dependences of wire aging on certain wire chamber operating parameters are discussed. Aging results from experimental detectors and laboratory experiments are summarized. Techniques for analysis of wire deposits and compositions of such deposits are discussed. Some effects of wire material and gas additives on wire aging are interpreted in chemical terms. A chemical model of wire aging is developed, and similarities of wire chamber plasmas to low-pressure rf-discharge plasmas are suggested. Procedures recommended for reducing wire aging effects are summarized. RP KADYK, JA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,1 CYCLOTRON RD,BERKELEY,CA 94720, USA. NR 86 TC 101 Z9 101 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 1 PY 1991 VL 300 IS 3 BP 436 EP 479 DI 10.1016/0168-9002(91)90381-Y PG 44 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA381 UT WOS:A1991FA38100003 ER PT J AU ABE, K ANTILOGUS, P ASTON, D BEAN, A BIENZ, T BIRD, F CALDWELL, D COYLE, P COYNE, D DATTE, P DUBOSCQ, J DUNWOODIE, W GAGNON, P HALE, D HALLEWELL, G HASEGAWA, K HILTON, M HUBER, J JACQUES, P JOHNSON, RA KAWAHARA, H KWON, Y LEITH, DWGS LU, A MARTINEZ, J MATHYS, L MCHUGH, S MORRISON, R MULLER, D NAGAMINE, T NUSSBAUM, M PAVEL, T PLANO, R RATCLIFF, B RENSING, P SANTHA, AKS SCHULTZ, D SHAPIRO, S SHOUP, A SIMOPOULOS, C SOLODOV, E STAMER, P STOCKDALE, I SUEKANE, F TOGE, N VAVRA, J WHITAKER, JS WILLIAMS, DA WILLIAMS, SH WITHERELL, M WILSON, RJ YELLIN, S YUTA, H AF ABE, K ANTILOGUS, P ASTON, D BEAN, A BIENZ, T BIRD, F CALDWELL, D COYLE, P COYNE, D DATTE, P DUBOSCQ, J DUNWOODIE, W GAGNON, P HALE, D HALLEWELL, G HASEGAWA, K HILTON, M HUBER, J JACQUES, P JOHNSON, RA KAWAHARA, H KWON, Y LEITH, DWGS LU, A MARTINEZ, J MATHYS, L MCHUGH, S MORRISON, R MULLER, D NAGAMINE, T NUSSBAUM, M PAVEL, T PLANO, R RATCLIFF, B RENSING, P SANTHA, AKS SCHULTZ, D SHAPIRO, S SHOUP, A SIMOPOULOS, C SOLODOV, E STAMER, P STOCKDALE, I SUEKANE, F TOGE, N VAVRA, J WHITAKER, JS WILLIAMS, DA WILLIAMS, SH WITHERELL, M WILSON, RJ YELLIN, S YUTA, H TI PRODUCTION OF 400 MIRRORS WITH HIGH VUV REFLECTIVITY FOR USE IN THE SLD CHERENKOV RING IMAGING DETECTOR SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB The Stanford Large Detector for experimental particle physics detection at the SLAC Linear Collider contains a Cherenkov ring imaging detector (CRID). The barrel CRID mirrors have been successfully produced and installed. The industrial mirror production process, the quality control of the mirrors produced, and the results of the vacuum ultraviolet (VUV) reflectivity and mirror-shape accuracy are described. An average reflectivity of at least 80% for light at 160 nm and 85% for light in the 180-230 nm wavelength range has been achieved in the production of over 400 mirrors of a typical size of 30 by 30 cm. The surface roughness and optical distortion measurements imply that the light loss due to scattering is a few percent of the incident light and the angular error due to shape distortion is less than 1 mrad. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. UNIV CALIF SANTA CRUZ,SANTA CRUZ INST PARTICLE PHYS,SANTA CRUZ,CA 95064. RUTGERS STATE UNIV,SERIN PHYS LAB,PISCATAWAY,NJ 08855. UNIV CINCINNATI,DEPT PHYS,CINCINNATI,OH 45221. BOSTON UNIV,DEPT PHYS,BOSTON,MA 02215. RP ABE, K (reprint author), TOHOKU UNIV,DEPT PHYS,SENDAI,MIYAGI 980,JAPAN. OI Bean, Alice/0000-0001-5967-8674 NR 7 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 1 PY 1991 VL 300 IS 3 BP 501 EP 510 DI 10.1016/0168-9002(91)90384-3 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA381 UT WOS:A1991FA38100006 ER PT J AU KADYK, JA VAVRA, J WISE, J AF KADYK, JA VAVRA, J WISE, J TI USE OF STRAW TUBES IN HIGH-RADIATION ENVIRONMENTS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID VERTEX CHAMBER; GAS-MIXTURES; DETECTOR; TESTS; CF4 AB We have investigated several aspects of straw tubes relating to their viability for use in SSC detectors. Gas temperature changes and the consequent gain changes resulting from the power dissipated in the tube at high rates are found to be relatively minor effects. Conduction through the gas between the wire and the wall is found to be the major mechanism by which heat is removed. Little aging is observed in straw tubes operating with any of several different gas mixtures. The dependence of aging on gas flow rate is found to be small. Water vapor at low concentrations (1000 ppm) is found to prevent breakdowns. Design and construction of straw tubes are discussed. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94309. RP KADYK, JA (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 29 TC 7 Z9 7 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 1 PY 1991 VL 300 IS 3 BP 511 EP 517 DI 10.1016/0168-9002(91)90385-4 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA381 UT WOS:A1991FA38100007 ER PT J AU CARROLL, JT JOSHI, U AUCHINCLOSS, P BERETVAS, A DEVLIN, T FLAUGHER, B HU, P KUNS, E WATTS, T RAGAN, K MORITA, Y SLIWA, K AF CARROLL, JT JOSHI, U AUCHINCLOSS, P BERETVAS, A DEVLIN, T FLAUGHER, B HU, P KUNS, E WATTS, T RAGAN, K MORITA, Y SLIWA, K TI THE CDF LEVEL-3 TRIGGER SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID ACP MULTIPROCESSOR SYSTEM; FASTBUS DATA ACQUISITION; EVENT BUILDER AB We discuss the architecture, operation, and performance of the Level 3 trigger used in the Fermilab CDF experiment in 1988-1989. This trigger used an on-line computer farm of 58 Motorola 68020 processors operating in parallel. The on-line programs were written mainly in Fortran and run in an environment similar to that used for off-line analysis. C1 RUTGERS STATE UNIV,DEPT PHYS & ASTRON,PISCATAWAY,NJ 08855. UNIV PENN,DEPT PHYS,PHILADELPHIA,PA 19104. UNIV TSUKUBA,DEPT PHYS,SAKURA,IBARAKI 305,JAPAN. TUFTS UNIV,DEPT PHYS,MEDFORD,MA 02155. RP CARROLL, JT (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 19 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 1 PY 1991 VL 300 IS 3 BP 552 EP 567 DI 10.1016/0168-9002(91)90390-C PG 16 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA381 UT WOS:A1991FA38100012 ER PT J AU TANNENBAUM, MJ AF TANNENBAUM, MJ TI SIMPLE FORMULAS FOR THE ENERGY-LOSS OF ULTRARELATIVISTIC MUONS BY DIRECT PAIR PRODUCTION SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID HEAVY-ION COLLISIONS; HIGGS-BOSON; BREMSSTRAHLUNG AB Simple formulas for direct pair production are derived from the general equation for deeply inelastic lepton scattering. Applications to energy loss by ultrarelativistic muons are discussed. For muons above the critical energy, E(c)mu approximately-greater-than 200 GeV, where the radiative effects of direct pair production and bremsstrahlung are dominant, the expressions for energy losses are considerably simplified when quoted in terms of the fractional energy loss per radiation length. The differential probability for direct pair production in a thickness x of material of radiation length X0 for an incident lepton of energy E, mass M, can be expressed as [GRAPHICS] where v is the energy of the produced pair, upsilon is the fractional energy loss, upsilon = v/E, m(e) is the electron mass and the variable z is defined by z = upsilon/M-4m(e). For indicent muons, this simple expression agrees very well with the exact calculation to within approximately 30% over the entire range of upsilon, for E approximately-greater-than 1 TeV. At higher energies complete screening occurs, and the agreement is further improved, to better than approximately 15% (except for the range 0.005 less-than-or-equal-to upsilon less-than-or-equal-to 0.01 where it is congruent-to 25%). The integral of this expression gives the energy loss due to direct pair production by muons (complete screening) which is accurate to approximately 10%: - 1/E dE(pair)/dx = 7.32 x 10(-5)/X0. RP TANNENBAUM, MJ (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 49 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 1 PY 1991 VL 300 IS 3 BP 595 EP 604 DI 10.1016/0168-9002(91)90396-8 PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA381 UT WOS:A1991FA38100018 ER PT J AU WICKHAM, KL AF WICKHAM, KL TI COMPUTER INTERACTIVE GRAPHICS FITTING OF EFFICIENCY CURVES FOR GE DETECTORS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID CALIBRATION AB A method of fitting the experimental data for a Ge detector efficiency curve using interactive computer graphics is described that allows the user to adjust the analytical fit to correct the undesired structure in the fitted curve sometimes introduced by the method of least squares. Special types of plots of the efficiency data are described that enhance the visual resolution and allow correction of distortions in the fitted efficiency curve that are not possible from the traditional log/log graph of the efficiency vs energy. RP WICKHAM, KL (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 1 PY 1991 VL 300 IS 3 BP 605 EP 610 DI 10.1016/0168-9002(91)90397-9 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA381 UT WOS:A1991FA38100019 ER PT J AU BRASURE, LW PRINJA, AK LAZO, MS MOREL, JE AF BRASURE, LW PRINJA, AK LAZO, MS MOREL, JE TI ION-IMPLANTATION AND ENERGY DEPOSITION PROFILES IN THE STRAIGHT-AHEAD APPROXIMATION WITH REALISTIC POTENTIALS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article ID INHOMOGENEOUS MATERIALS; RANGE PROFILES; DISTRIBUTIONS; TRANSPORT; EQUATION; DAMAGE AB The straight-ahead approximation to the Boltzmann equation is revisted and shown to be a viable and economical alternative to traditional, computationally demanding approaches for a class of ion transport problems. In conjunction with realistic potentials, and a fast and efficient numerical scheme, the model yields quite accurate profiles of implanted ions and of deposited energy for MeV P implantation in a Si substrate. Extensive results are presented for energetic heavy ion transport in multilayer media and mixtures. For 500 keV Bi ions incident on a Ge/Si bilayer implantation profiles are seen to be sensitive to the choice of interatomic potential. For a given potential, the effect of the disparate mass ratio on the energy spectrum is investigated as primary ions slow down across the interface from Ge into Si. Results are also presented for the partitioning of the primary ion (Bi and O) energy amongst the elements of the high-T(c) superconductor material YBa2Cu3O7. C1 UNIV NEW MEXICO,DEPT CHEM & NUCL ENGN,ALBUQUERQUE,NM 87131. UNIV CALIF LOS ALAMOS SCI LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87545. NR 24 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD FEB PY 1991 VL 53 IS 2 BP 134 EP 143 DI 10.1016/0168-583X(91)95648-W PG 10 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FC489 UT WOS:A1991FC48900004 ER PT J AU KRUGER, K BERGERFURTH, A BURGER, S POHL, P WIMMERS, M CLEVELAND, JC AF KRUGER, K BERGERFURTH, A BURGER, S POHL, P WIMMERS, M CLEVELAND, JC TI PREPARATION, CONDUCT, AND EXPERIMENTAL RESULTS OF THE AVR LOSS-OF-COOLANT ACCIDENT SIMULATION TEST SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article AB A loss-of-coolant accident (LOCA) is one of the most severe accidents for a nuclear power plant. To demonstrate inherent safety characteristics incorporated into small high-temperature gas-cooled reactor (HTGR) designs, LOCA simulation tests have been conducted at the Arbeitsgemeinschaft Versuchsreaktor (AVR), the German pebble-bed high-temperature reactor plant. The AVR is the only nuclear power plant ever to have been intentionally subjected to LOCA conditions without emergency cooling. The planning and licensing activities including pretest predictions performed for the LOCA test are described, and the conduct of the test and experimental results are presented. The LOCA test was planned to create conditions that would exist if a rapid LOCA occurred with the reactor operating at full power. The test demonstrated this reactor's safe response to an accident in which the coolant escapes from the reactor core and no emergency system is available to provide coolant flow to the core. The test is of special interest because it demonstrates the inherent safety features incorporated into optimized modular HTGR designs. The main LOCA test lasted for 5 days. After the test began, core temperatures increased for approximately 13 h and then gradually and continually decreased as the rate of heat dissipation from the core exceeded the simulated decay power. Throughout the test, temperatures remained below limiting values for the core and other reactor components. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP KRUGER, K (reprint author), ARBEITSGEMEINSCHAFT VERSUCHSREAKTOR GMBH,DUSSELDORF,GERMANY. NR 7 TC 8 Z9 8 U1 0 U2 2 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 FEB PY 1991 VL 107 IS 2 BP 99 EP 113 PG 15 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EV534 UT WOS:A1991EV53400001 ER PT J AU LIEW, SL KU, LP AF LIEW, SL KU, LP TI MONTE-CARLO CALCULATION OF DELAYED GAMMA DOSE-RATE IN COMPLEX-GEOMETRY USING THE CONCEPT OF EFFECTIVE DELAYED GAMMA PRODUCTION CROSS-SECTION SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Article ID FUSION TEST REACTOR AB With appropriate approximations, the delayed gamma dose rate problem can be formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed gamma transport equations take the same form as the coupled neutron-prompt gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the flux coupling step required in conventional calculations and makes it easier to handle complex, multidimensional problems, especially those that call for Monte Carlo calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method is complex geometry are illustrated by its application in the Monte Carlo solution of a practical design problem. RP LIEW, SL (reprint author), PRINCETON UNIV,PRINCETON PLASMA PHYS LAB,POB 451,PRINCETON,NJ 08543, USA. NR 63 TC 7 Z9 7 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 FEB PY 1991 VL 107 IS 2 BP 114 EP 130 PG 17 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EV534 UT WOS:A1991EV53400002 ER PT J AU MARCHLEUBA, J BLAKEMAN, ED AF MARCHLEUBA, J BLAKEMAN, ED TI A MECHANISM FOR OUT-OF-PHASE POWER INSTABILITIES IN BOILING WATER-REACTORS SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Note ID STABILITY; BWR AB A study of the stability of subcritical neutronic modes in boiling water reactors that can result in out-of-phase power oscillations is presented. A mechanism has been identified for this type of instability, and the LAPUR code has been modified to account for it. Numerical results show that there is a region in the power flow operating map where an out-of-phase instability mode is likely even if the corewide mode is stable. RP MARCHLEUBA, J (reprint author), OAK RIDGE NATL LAB,DIV INSTRUMENTAT & CONTROLS,OAK RIDGE,TN 37831, USA. OI March-Leuba, Jose/0000-0002-2173-8552 NR 4 TC 72 Z9 72 U1 0 U2 2 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 FEB PY 1991 VL 107 IS 2 BP 173 EP 179 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EV534 UT WOS:A1991EV53400006 ER PT J AU CRAMER, SN LEE, TY AF CRAMER, SN LEE, TY TI MONTE-CARLO ANALYSIS OF A NEUTRON STREAMING EXPERIMENT SO NUCLEAR SCIENCE AND ENGINEERING LA English DT Note AB The analysis of neutron spectra emitted from a 14-MeV source and streaming through a void steel duct embedded in concrete is carried out using a multigroup Monte Carlo code on a small computer. The calculated results are compared with experimental results and with other calculational analyses involving continuous energy Monte Carlo methods. The computational methods agree when the P(N) expansion of the multigroup method is sufficiently extended. Some discrepancies with the experimental results, found in earlier analyses, still remain; and these are investigated with regard to the use of a new modification of the evaluated iron data, the spreading of the calculated results for comparison with experimental spectra, and various other modeling details. C1 KOREA ATOM ENERGY RES INST,CHUNGNAM,SOUTH KOREA. RP CRAMER, SN (reprint author), OAK RIDGE NATL LAB,CTR RADIAT SHIELDING INFORMAT,POB 2008,OAK RIDGE,TN 37831, USA. NR 18 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 0029-5639 J9 NUCL SCI ENG JI Nucl. Sci. Eng. PD FEB PY 1991 VL 107 IS 2 BP 180 EP 187 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EV534 UT WOS:A1991EV53400007 ER PT J AU GROSS, KC HUMENIK, KE AF GROSS, KC HUMENIK, KE TI SEQUENTIAL PROBABILITY RATIO TEST FOR NUCLEAR-PLANT COMPONENT SURVEILLANCE SO NUCLEAR TECHNOLOGY LA English DT Article AB It is common practice in nuclear power plants to install redundant sensors to monitor critical physical variables such as pressures, temperatures, and radiation levels. The design and testing of an extremely sensitive component-operability surveillance algorithm based on the sequential probability ratio test (SPRT) are reported. The SPRT technique processes the stochastic components of digitized signals from identical sensors on two or more components in an operating reactor for the detection and annunciation of off-normal operation. Information from the SPRT can provide a reactor operator with early identification of conditions that could lead to plant operational degradation, thus enabling him or her to terminate or avoid events that might challenge safety or radiological performance guidelines. The SPRT enhances plant availability and economics by minimizing unnecessary reactor trips caused in conventional systems by occasional spurious data that might exceed a simple high/low limit check. An example application of the SPRT for the surveillance of primary coolant pump operability in the Experimental Breeder Reactor II is presented. RP GROSS, KC (reprint author), ARGONNE NATL LAB,DIV REACTOR ANAL & SAFETY,9700 S CASS AVE,ARGONNE,IL 60439, USA. NR 5 TC 29 Z9 29 U1 2 U2 8 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 FEB PY 1991 VL 93 IS 2 BP 131 EP 137 PG 7 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EU830 UT WOS:A1991EU83000002 ER PT J AU DIAMOND, DJ MIRKOVIC, D HSU, CJ FITZPATRICK, R AF DIAMOND, DJ MIRKOVIC, D HSU, CJ FITZPATRICK, R TI THE POTENTIAL FOR CATASTROPHIC FUEL DAMAGE DURING BEYOND-DESIGN-BASIS OVERPRESSURIZATION ACCIDENTS IN A BOILING WATER-REACTOR SO NUCLEAR TECHNOLOGY LA English DT Article AB Beyond-design-basis overpressurization events in a boiling water reactor are studied to determine if they can lead to catastrophic fuel damage, i.e., fuel fragmentation and the rapid disruption of coolable geometry. This is part of a broader study for the U.S. Nuclear Regulatory Commission to question the adequacy of the events previously selected as the design basis, and to determine if any sequences need more analysis in the context of severe accident research. The RELAP5/MOD2 calculations with failures of the reactor trip and recirculation pump trip, as well as safety and relief valve failures, show that no catastrophic fuel damage is expected. This, in combination with the low frequency of occurrence that can be inferred from the literature, results in a recommendation that no further consideration be given to these events at this time. RP DIAMOND, DJ (reprint author), BROOKHAVEN NATL LAB,DEPT NUCL ENGN,RISK EVALUAT GRP,BLDG 130,UPTON,NY 11973, USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD FEB PY 1991 VL 93 IS 2 BP 158 EP 165 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EU830 UT WOS:A1991EU83000005 ER PT J AU RIEMKE, RA AF RIEMKE, RA TI COUNTERCURRENT-FLOW LIMITATION MODEL FOR RELAP5/MOD3 SO NUCLEAR TECHNOLOGY LA English DT Article AB A countercurrent flow limitation model is incorporated into the RELAP5/MOD3 system transient analysis code. The model is based on the form used by Bankoff et al., and it is implemented in a manner similar to the RELAP5 choking model. Simulations using Dukler and Smith's air/water flooding test problem demonstrate the ability of the code to significantly improve its comparison to data when a flooding correlation suggested in Dukler and Smith's study is used. RP RIEMKE, RA (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,POB 1625,IDAHO FALLS,ID 83415, USA. NR 16 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 FEB PY 1991 VL 93 IS 2 BP 166 EP 173 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EU830 UT WOS:A1991EU83000006 ER PT J AU LARSON, TK CONDIE, KG POLKINGHORNE, ST BUESCHER, BJ AF LARSON, TK CONDIE, KG POLKINGHORNE, ST BUESCHER, BJ TI SMALL-SCALE EXPERIMENTS CONDUCTED TO SUPPORT INVESTIGATION OF HYPOTHETICAL DESIGN-BASIS LOCA PHENOMENA IN THE ADVANCED TEST REACTOR SO NUCLEAR TECHNOLOGY LA English DT Article AB An unheated, integral thermal-hydraulic facility scaled to the Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory was designed, constructed, and operated to gather simulated large-break loss-of-coolant accident (LOCA) data for use in assessing codes used in ATR analysis. Eighteen experiments were performed in the facility to establish a data base consisting of qualitative and quantitative information for assessment purposes. The effects of initial liquid temperature, break location, and use of safety injection are examined. The results obtained offer significant insights about thermal-hydraulic processes in a complex loop during subatmospheric pressure operating conditions similar to those expected during a hypothetical LOCA in the ATR. C1 EG&G IDAHO INC,IDAHO NATL ENGN LAB,ENERGY & SYST TECHNOL GRP,IDAHO FALLS,ID 83415. EG&G IDAHO INC,IDAHO NATL ENGN LAB,REACTOR ANAL UNIT,IDAHO FALLS,ID 83415. EG&G IDAHO INC,IDAHO NATL ENGN LAB,ADV TEST REACTOR SAFETY ENGN GRP,IDAHO FALLS,ID 83415. RP LARSON, TK (reprint author), EG&G IDAHO INC,ARTIFICIAL INTELLIGENCE & INFORMAT ENGN GRP,IDAHO NATL ENGN LAB,IDAHO FALLS,ID 83415, USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 SN 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD FEB PY 1991 VL 93 IS 2 BP 174 EP 194 PG 21 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EU830 UT WOS:A1991EU83000007 ER PT J AU POLKINGHORNE, ST LARSON, TK BUESCHER, BJ AF POLKINGHORNE, ST LARSON, TK BUESCHER, BJ TI RELAP5 SIMULATION OF ADVANCED TEST REACTOR SCALED LOCA EXPERIMENT-7, EXPERIMENT-8, EXPERIMENT-12, AND EXPERIMENT-14 SO NUCLEAR TECHNOLOGY LA English DT Article AB The RELAP5 computer code is used to simulate four small-scale loss-of-coolant accident (LOCA) experiments conducted at Idaho National Engineering Laboratory (INEL). The purpose of the study is to help assess RELAP5 under conditions similar to those expected during a large-break LOCA at INEL's Advanced Test Reactor (ATR). During an ATR large-break LOCA, it is expected that the primary system pressure will rapidly decrease from the initial operating pressure (approximately 2.55 MPa) to subatmospheric conditions governed by the primary coolant temperature. Flashing will occur in the high points of the system and air ingress from the break is possible. The RELAP5 code had not previously been assessed under these conditions. The results show that RELAP5 accurately predicted pressures, water levels, and air ingress behavior, thus providing confidence in the ability of the code to simulate an ATR large-break LOCA. C1 EG&G IDAHO INC,IDAHO NATL ENGN LAB,ARTIFICIAL INTELLIGENCE & INFORMATION ENGN GRP,IDAHO FALLS,ID 83415. EG&G IDAHO INC,IDAHO NATL ENGN LAB,ADV TEST REACTOR SAFETY ENGN GRP,IDAHO FALLS,ID 83415. RP POLKINGHORNE, ST (reprint author), EG&G IDAHO INC,IDAHO NATL ENGN LAB,REACTOR SAFETY ANAL UNIT,POB 1625,IDAHO FALLS,ID 83415, USA. NR 6 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 0029-5450 J9 NUCL TECHNOL JI Nucl. Technol. PD FEB PY 1991 VL 93 IS 2 BP 240 EP 251 PG 12 WC Nuclear Science & Technology SC Nuclear Science & Technology GA EU830 UT WOS:A1991EU83000011 ER PT J AU BILYARD, GR AF BILYARD, GR TI DISTRIBUTIONS OF POLAR POLYCHAETES - TEST OF A HYPOTHESIS SO OPHELIA LA English DT Article DE POLYCHAETA; DEPTH RANGES; ARCTIC OCEAN; ANTARCTIC OCEAN AB From the hypothesis that the relative fitness of species that forage over large areas increases as food supplies decrease, Jumars & Fauchald (1977) predicted that polychaete species replacements "should occur over short distances where gradients in ... food abundance are steep." They suggested that depth ranges of Arctic and Antarctic polychaetes be compared as one test of this prediction. Depth ranges of Antarctic species should exceed those of Arctic species because the depths over which similar quantities of food occur are greater in the Antarctic Ocean than in the Arctic Ocean. This paper compares the depth ranges of Arctic and Antarctic polychaete species graphically and statistically for four major polychaete feeding guilds, and for all polychaete species reported from these areas. Results indicate that mean depth ranges of Arctic and Antarctic polychaete species do not differ significantly (P > 0.025) for surface deposit-feeders, subsurface deposit-feeders, filter-feeders, or carnivores, based on an experimentwise error rate of P < 0.05. The mean depth range of all Antarctic polychaete species is significantly greater (P < 0.025) than the mean depth range of all Arctic polychaete species, but the significant difference (P = 0.023) may partially reflect biases in sampling intensity between the two regions. At best, data on the depth ranges of Arctic and Antarctic species provide weak support for the prediction made by Jumars & Fauchald (1977). RP BILYARD, GR (reprint author), PACIFIC NW LAB, K6-55,POB 999, RICHLAND, WA 99352 USA. NR 19 TC 1 Z9 1 U1 0 U2 1 PU OPHELIA PUBLICATIONS PI HELSINGOR PA STRANDPROMENADEN 5, DK-3000 HELSINGOR, DENMARK SN 0078-5326 J9 OPHELIA JI Ophelia PD FEB PY 1991 SU 5 BP 529 EP 538 PG 10 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA FP608 UT WOS:A1991FP60800050 ER PT J AU ZARDECKI, A AF ZARDECKI, A TI EFFECT OF RECONDENSATION ON THE OPTICAL-QUALITY OF A CLEARED CHANNEL IN A WATER CLOUD SO OPTICAL ENGINEERING LA English DT Article DE HIGH-ENERGY LASERS; BEAM QUALITY; IMAGING ID MODULATION TRANSFER-FUNCTION; SPATIAL-FREQUENCY; AEROSOLS; APPROXIMATION; DROPLETS AB The interactions of high-energy laser beams with aerosols are studied in the diffusive regime within the framework of a nonlinear transport equation. A numerical algorithm allows us to advance along the distance of propagation by using spatial steps small compared to the scattering optical depth. We emphasize the effect of laser-assisted imaging, in which-due to the cloud clearing-the roll-off of the modulation transfer function decreases with the distance of propagation. We study the effect of recondensation on the propagation of a low-energy laser beam. The principal findings are the independence of the pulse shape of the turbulence strength and the suppression of the high-energy laser-assisted imaging effect. RP ZARDECKI, A (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,SAFEGUARDS SYST GRP,MS E541,LOS ALAMOS,NM 87545, USA. NR 16 TC 0 Z9 0 U1 1 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 FEB PY 1991 VL 30 IS 2 BP 219 EP 223 DI 10.1117/12.55779 PG 5 WC Optics SC Optics GA EX618 UT WOS:A1991EX61800012 ER PT J AU ANDREWS, MA GOULD, GL AF ANDREWS, MA GOULD, GL TI PHOTOINDUCED NET [2 + 2 + 2] CYCLOREVERSION OF PLATINUM(II) GLYCOLATE COMPLEXES - A NEW APPROACH TO THE GENERATION OF REDUCED, COORDINATIVELY UNSATURATED METAL SPECIES AND THE ACTIVATION OF CARBOHYDRATE CARBON-CARBON SINGLE BONDS SO ORGANOMETALLICS LA English DT Article ID TRANSITION-METALS; COMPLEXES; HYDROGENATION; ELIMINATION; REACTIVITY; KETONES; BONDS AB Photolysis of thermally stable (1,2-bis(diphenylphosphino)ethane)platinum(II) glycolate complexes causes a facile net [2 + 2 + 2] cycloreversion of the 2,5-dioxaplatinacyclopentane moiety to give two organic carbonyl compounds and a reactive (dppe)Pt0 intermediate, as shown by trapping with dppe, ethylene, or hydrogen. Photolysis under hydrogen in the presence of (PPh3)4RuH2 leads to hydrocracking of the glycol carbon-carbon single bond. RP ANDREWS, MA (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 26 TC 26 Z9 26 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD FEB PY 1991 VL 10 IS 2 BP 387 EP 389 DI 10.1021/om00048a009 PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA EY681 UT WOS:A1991EY68100009 ER PT J AU ROY, T MITCHELL, TE AF ROY, T MITCHELL, TE TI TWIN BOUNDARY ENERGIES IN YBA2CU3O7-X AND LA2CUO4 SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID MICROSTRUCTURE; CERAMICS; SIZE AB Colonies of parallel twins are observed in YBa2Cu3O7-x and La2CuO4, as well as in many other materials which undergo a tetragonal to orthorhombic or equivalent transformation. The spacing of such twins is found to vary with the colony size. It is shown that this variation can be used to calculate the twin boundary energy, gamma. The total energy of a twin colony is the sum of the twin boundary energy associated with the presence of the twin boundaries and the strain energy of the coherent lenticular ends. Minimization of the total energy of the system shows that the twin thickness (t), should be proportional to (gamma-L/epsilon-2)1/2 where L is the colony size and epsilon is the transformation strain. Plots of t against square-root L yield straight lines for both YBa2Cu3O7-x and La2CuO4 and gamma can be calculated from the slopes giving values of 2.8 and 5.3 mJm-2 respectively. RP ROY, T (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 19 TC 35 Z9 35 U1 0 U2 2 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 FEB PY 1991 VL 63 IS 2 BP 225 EP 232 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA FC844 UT WOS:A1991FC84400004 ER PT J AU ROBERTSON, IM VETRANO, JS KIRK, MA JENKINS, ML AF ROBERTSON, IM VETRANO, JS KIRK, MA JENKINS, ML TI ON THE FORMATION OF VACANCY TYPE DISLOCATION LOOPS FROM DISPLACEMENT CASCADES IN NICKEL SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID THERMAL SPIKE; COLLAPSE; METALS AB The damage structures produced in Ni by heavy-ion irradiations with 50 keV Kr+ and 50 and 100 keV Ni+ ions have been studied as a function of irradiation temperature (30 and 300 K) and ion dose (10(15)-10(17) ions m-2). Both irradiations and electron microscopy were performed in the HVEM-Accelerator facility at Argonne National Laboratory. The effects of the irradiations were characterized in terms of the loop densities, loop sizes and the Burgers vector distribution. Dislocation loops were formed from isolated displacement cascades both at room temperature and 30 K, although the loop formation probability was significantly lower at 30 K. Additional loops appeared when specimens irradiated at 30 K were warmed to room temperature. At both irradiation temperatures the defect production rate decreased with increasing ion dose. During continued irradiation it was observed that new loops formed from isolated displacement cascades, and some pre-existing loops disappeared, shifted position of coalesced with a neighbouring loop. These effects can be explained in terms of the molecular dynamic computer simulation model that displays 'local melting' within the displacement cascade. The decreasing defect production rate with increasing ion dose is attributed to the coalescence of existing loops and the annihilation/reformation of loops that occurs when a fresh cascade spatially overlaps with the existing loops. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV OXFORD,DEPT MAT,OXFORD OX1 3PH,ENGLAND. RP ROBERTSON, IM (reprint author), UNIV ILLINOIS,DEPT MAT SCI & ENGN,1304 W GREEN ST,URBANA,IL 61801, USA. NR 30 TC 29 Z9 29 U1 1 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 FEB PY 1991 VL 63 IS 2 BP 299 EP 318 PG 20 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA FC844 UT WOS:A1991FC84400009 ER PT J AU HORTON, JA BAKER, I YOO, MH AF HORTON, JA BAKER, I YOO, MH TI SLIP-PLANE DISORDERING IN STOICHIOMETRIC NI3AL SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID TEMPERATURE; BORON; STABILITY; ALUMINUM; ALLOYS; YIELD AB Observations during in situ straining experiments on stoichiometric Ni3Al in a transmission electron microscope are presented showing that a non-conservative loop generation mechanism operates in highly-deformed slip bands. Apparently, after passage of many superlattice dislocations the antiphase boundary energy (APB) in the slip band is lowered, superpartial separations increase, and some defects (such as vacancy and anti-site) coalesce and aid the formation of the loops. These observations correlate well with recent suggestions that non-planar APBs are present and can glide. Similar experiments in alloys that do not order do not produce such loops. These loops serve as pinning points to passage of subsequent dislocations. The separations of superpartial dislocations measured under load are greater than those measured in bulk deformed but unloaded specimens. C1 DARTMOUTH COLL,THAYER SCH ENGN,HANOVER,NH 03755. RP HORTON, JA (reprint author), OAK RIDGE NATL LAB,DIV MET & CERAM,POB 2008,OAK RIDGE,TN 37831, USA. RI Barsoum, Michel/I-2842-2012 OI Barsoum, Michel/0000-0001-7800-3517 NR 32 TC 36 Z9 36 U1 1 U2 3 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 FEB PY 1991 VL 63 IS 2 BP 319 EP 335 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA FC844 UT WOS:A1991FC84400010 ER PT J AU WOLF, D AF WOLF, D TI CORRELATION BETWEEN STRUCTURE, ENERGY AND SURFACE-TENSION FOR FREE SURFACES IN BCC METALS SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID CUBIC TRANSITION-METALS; EMBEDDED-ATOM-METHOD; THIN-FILMS; BODY; RELAXATIONS; CRYSTALS; DEFECTS; STRESS; MODEL AB A many-body potential of the Finnis-Sinclair type for Mo and a Johnson-type pair potential for alpha-Fe are used to determine the zero-temperature structures, energies and surface tensions of a variety of free surfaces in b.c.c. metals. The variation in the surface energy and tension as a function of the two variables characterizing the surface normal n is found to be similar for the two potentials , and our results for the principal surfaces of Mo agree with those presented recently by Ackland and Finnis. However, while the pair potential yields an outward relaxation of the surface plane in some cases and an inward relaxation in others, the many-body potential yields an inward relaxation for all surfaces considered. This difference is shown to arise from the very different magnitudes of the surface tensions obtained for the two types of potential which, in turn, are shown to be closely connected with the volume dependence of the related perfect-crystal cohesive energies. For both potentials a strong correlation is found between the number of broken nearest- and second-nearest neighbour bonds on the one hand, and the surface tensions and energies on the other. RP WOLF, D (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 28 TC 12 Z9 12 U1 1 U2 6 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 FEB PY 1991 VL 63 IS 2 BP 337 EP 361 PG 25 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA FC844 UT WOS:A1991FC84400011 ER PT J AU KABURAGI, Y BRAGG, RH HISHIYAMA, Y AF KABURAGI, Y BRAGG, RH HISHIYAMA, Y TI ELECTRICAL-RESISTIVITY, TRANSVERSE MAGNETORESISTANCE AND HALL-COEFFICIENT IN PYROLYTIC CARBON - CORRELATION WITH INTERLAYER SPACING D002 SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article ID NEGATIVE MAGNETORESISTANCE; GRAPHITE AB The interlayer spacing d002, X-ray diffraction profiles of the (110), (112) and (006) lines and the dependence of the electrical resistivity, Hall coefficient and transverse magnetoresistance at liquid nitrogen temperature on d002 were measured for pyrolytic carbons with a wide range of d002. For selected samples the temperature dependence of the resistivity and magnetoresistance were measured from 2.4 to 290 K in magnetic fields up to 3 T. The d002 values for which discontinuities in slopes or sign reversals occur for each of the resistivity, magnetoresistance and Hall coefficient against d002 curves are common, and are 3.367, 3.380 and 3.420 angstrom. These values are identical to those for which stepwise changes occur in the interlaver spacing observed in annealing studies of cokes and pyrolytic carbons, and in fast-neutron irradiation and grinding of graphite. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT MAT SCI & MINERAL ENGN,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP KABURAGI, Y (reprint author), MUSASHI INST TECHNOL,1-28-1 TAMAZUTSUMI,SETAGAYA KU,TOKYO 158,JAPAN. NR 28 TC 5 Z9 5 U1 0 U2 1 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 FEB PY 1991 VL 63 IS 2 BP 417 EP 436 DI 10.1080/13642819108205947 PG 20 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA FC842 UT WOS:A1991FC84200004 ER PT J AU CHUNG, SWM ROBINSON, J THOMPSON, GE WOOD, GC ISAACS, HS AF CHUNG, SWM ROBINSON, J THOMPSON, GE WOOD, GC ISAACS, HS TI AN X-RAY ABSORPTION STUDY OF BARRIER-TYPE ANODIC FILMS FORMED ON ALUMINUM IN CHROMATE ELECTROLYTES SO PHILOSOPHICAL MAGAZINE B-PHYSICS OF CONDENSED MATTER STATISTICAL MECHANICS ELECTRONIC OPTICAL AND MAGNETIC PROPERTIES LA English DT Article AB An X-ray absorption study of anodic films formed on aluminium in chromate electrolytes has been undertaken to investigate the nature of the incorporated chromium species. From the shift in chromium edge position, due to change in valency state, and from the observation of a pre-edge peak, or shape resonance, associated with Cr(VI) in tetrahedral coordination, it is evident that the anodic alumina contains both Cr(III) and Cr(VI) states. More specifically, the Cr(VI) state is probably associated with chromate and dichromate anions initially adsorbed at the film/electrolyte interface and incorporated under the field into the thickening alumina film. There is an approximately uniform uptake of chromium species, with thicker films being associated largely with the Cr(III) state. In order to explain the outward mobility of chromium species during film growth, it is evident that a field-induced transformation proceeds whereby chromate and dichromate anions are transformed to outwardly mobile Cr3+ catonic species. The transformation may be associated with structural rearrangement of the alumina film and/or electron injection at the film/electrolyte interface during anodizing. C1 UNIV WARWICK,DEPT PHYS,COVENTRY CV4 7AL,W MIDLANDS,ENGLAND. BROOKHAVEN NATL LAB,UPTON,NY 11973. RP CHUNG, SWM (reprint author), UNIV MANCHESTER,INST SCI & TECHNOL,CTR CORROS & PROTECT,MANCHESTER M60 1QD,LANCS,ENGLAND. NR 17 TC 26 Z9 26 U1 0 U2 4 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 FEB PY 1991 VL 63 IS 2 BP 557 EP 571 DI 10.1080/13642819108205960 PG 15 WC Materials Science, Multidisciplinary; Mechanics; Physics, Applied; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA FC842 UT WOS:A1991FC84200017 ER PT J AU CHURCHILL, ME PEAK, JG PEAK, MJ AF CHURCHILL, ME PEAK, JG PEAK, MJ TI CORRELATION BETWEEN CELL-SURVIVAL AND DNA SINGLE-STRAND BREAK REPAIR PROFICIENCY IN THE CHINESE-HAMSTER OVARY CELL-LINES AA8 AND EM9 IRRADIATED WITH 365-NM ULTRAVIOLET-A RADIATION SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Article ID CULTURED MAMMALIAN-CELLS; 2 RADIOSENSITIVE CLONES; CHO CELLS; ATAXIA-TELANGIECTASIA; HYDROGEN-PEROXIDE; ACTION SPECTRA; SENSITIVE MUTANTS; HUMAN-FIBROBLASTS; FAR-ULTRAVIOLET; CYTO-TOXICITY AB Cell survival parameters and the induction and repair of DNA single-strand breaks were measured in two Chinese hamster ovary cell lines after irradiation with monochromatic UVA radiation of wavelength 365 nm. The radiosensitive mutant cell line EM9 is known to repair ionizing-radiation-induced single-strand breaks (SSB) more slowly than the parent line AA8. EM9 was determined to be 1.7-fold more sensitive to killing by 365-nm radiation than AA8 at the 10% survival level, and EM9 had a smaller shoulder region on the survival curve (alpha = 1.76) than AA8 (alpha = 0.62). No significant differences were found between the cell lines in the initial yields of SSB induced either by gamma-radiation (as determined by alkaline sucrose gradient sedimentation) or by 365-nm UVA (as determined by alkaline elution). For measurement of initial SSB, cells were irradiated at 0.5-degrees-C to minimize DNA repair processes. Rejoining of 365-nm induced SSB was measured by irradiating cells at 0.5-degrees-C, allowing them to repair at 37-degrees-C in full culture medium, and then quantitating the remaining SSB by alkaline elution. The repair of these breaks followed biphasic kinetics in both cell lines. EM9 repaired the breaks more slowly (t1/2 values of 1.3 and 61.3 min) than did AA8 (t1/2 values of 0.9 and 53.3 min), and EM9 also left more breaks unrepaired 90 min after irradiation (24% vs 8% for AA8). Thus, the sensitivity of EM9 to 365-nm radiation correlated with its deficiency in repairing DNA lesions revealed as SSB in alkaline elution. These results suggest that DNA may be a critical target in 365-nm induced cellular lethality and that the ability of AA8 and EM9 cells to repair DNA strand breaks may be related to their ability to survive 365-nm radiation. RP CHURCHILL, ME (reprint author), ARGONNE NATL LAB,DIV BIOL & MED RES,MOLEC PHOTOBIOL GRP,9700 S CASS AVE,ARGONNE,IL 60439, USA. FU NCI NIH HHS [R01-CA34492, R01-CA37848] NR 52 TC 50 Z9 50 U1 1 U2 4 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD FEB PY 1991 VL 53 IS 2 BP 229 EP 236 DI 10.1111/j.1751-1097.1991.tb03927.x PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA EY916 UT WOS:A1991EY91600011 PM 2011627 ER PT J AU ARNOLD, WA AF ARNOLD, WA TI PERSONAL PERSPECTIVE - EXPERIMENTS SO PHOTOSYNTHESIS RESEARCH LA English DT Item About an Individual DE AUTOBIOGRAPHY; PHOTOSYNTHETIC UNIT; EFFICIENCY OF PHOTOSYNTHESIS; EXCITATION ENERGY TRANSFER; DELAYED LIGHT EMISSION; THERMOLUMINESCENCE; ELECTROLUMINESCENCE AB In this article, I have provided a brief history of my life. After tracing my family background and my early interest in physical sciences, I discuss how I entered biology under the influence of Robert Emerson. I have always enjoyed doing experiments and this led to new measurements and analyses of 'chlorophyll unit', efficiency of photosynthesis, excitation energy transfer, delayed light emission, thermoluminescence and electroluminescence in photosynthetic organisms. It is my view that discoveries are made because we follow our scientific curiosities. C1 OAK RIDGE NATL LAB,DIV BIOL,OAK RIDGE,TN. NR 1 TC 23 Z9 23 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0166-8595 J9 PHOTOSYNTH RES JI Photosynth. Res. PD FEB PY 1991 VL 27 IS 2 BP 73 EP 82 DI 10.1007/BF00033247 PG 10 WC Plant Sciences SC Plant Sciences GA FE707 UT WOS:A1991FE70700001 PM 24414571 ER PT J AU OLSON, CG AF OLSON, CG TI PHOTOEMISSION SPECTROSCOPY OF HIGH-TC SUPERCONDUCTORS SO PHYSICA B LA English DT Article; Proceedings Paper CT 19TH INTERNATIONAL CONF ON LOW TEMPERATURE PHYSICS ( LT-19 ) CY AUG 16-22, 1990 CL BRIGHTON, ENGLAND SP INT UNION PURE & APPL PHYS, OXFORD INSTRUMENTS, ELSEVIER NORTH HOLLAND PUBL, UNIV SUSSEX, INST PHYS, USAF, GEC ID ANGLE-RESOLVED PHOTOEMISSION; CA-CU-O; RESONANT PHOTOEMISSION; BI2SR2CACU2O8; STATES; GAP AB High-resolution, angle-resolved photoemission studies of high-temperature superconductors have yielded a great deal of information about the electronic states near the Fermi level. For Bi 2212, a gap (2-DELTA/kT(c) = 7) is seen. The angle dependent studies show the gap to be isotropic in the plane. In the normal state, bands are seen to disperse through the Fermi level, indicating a Fermi surface that is consistent with that obtained in a single particle calculation. The states below the Fermi level, however, are heavier than single particle bands and the lifetime broadening is effectively linear in energy. C1 IOWA STATE UNIV SCI & TECHNOL,AMES LAB,AMES,IA 50011. NR 15 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD FEB PY 1991 VL 169 IS 1-4 BP 112 EP 115 DI 10.1016/0921-4526(91)90216-2 PG 4 WC Physics, Condensed Matter SC Physics GA FL630 UT WOS:A1991FL63000020 ER PT J AU LIN, SW RAN, QZ ADENWALLA, S ZHAO, Z KETTERSON, JB TAILLEFER, L HINKS, DG LEVY, M SARMA, BK AF LIN, SW RAN, QZ ADENWALLA, S ZHAO, Z KETTERSON, JB TAILLEFER, L HINKS, DG LEVY, M SARMA, BK TI ULTRASONIC VELOCITY DETERMINATION OF THE PHASE-DIAGRAM OF UPT3 SO PHYSICA B LA English DT Article; Proceedings Paper CT 19TH INTERNATIONAL CONF ON LOW TEMPERATURE PHYSICS ( LT-19 ) CY AUG 16-22, 1990 CL BRIGHTON, ENGLAND SP INT UNION PURE & APPL PHYS, OXFORD INSTRUMENTS, ELSEVIER NORTH HOLLAND PUBL, UNIV SUSSEX, INST PHYS, USAF, GEC ID MAGNETIC-FIELD; TRANSVERSE SOUND; ANISOTROPY AB We report ultrasonic velocity measurements on two UPt3 samples with three different field orientations (H-perpendicular-to-c, H-parallel-to-c and H-tripple-over-that-c = 45-degrees). Velocity changes are observed at constant temperatures, as the field is swept, at the upper critical fiel H(c2) and at the flux lattice transition H(fl). Velocity changes are also observed at T(c)+ the upper transition temperature and T(c)- the lower transition temperature as the temperature is swept at constant fields. Complete phase diagrams for UPt3 obtained by a single measurement technique on the same samples in the H-T plane are presented. C1 NORTHWESTERN UNIV,DEPT PHYS,EVANSTON,IL 60208. CNRS,CTR RECH TRES BASSES TEMP,F-38042 GRENOBLE,FRANCE. ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP LIN, SW (reprint author), UNIV WISCONSIN,DEPT PHYS,MILWAUKEE,WI 53201, USA. RI Ketterson, John/B-7234-2009 NR 9 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD FEB PY 1991 VL 169 IS 1-4 BP 493 EP 494 DI 10.1016/0921-4526(91)90292-M PG 2 WC Physics, Condensed Matter SC Physics GA FL630 UT WOS:A1991FL63000096 ER PT J AU ARONSON, MC DIERKER, SB DENNIS, BS CHEONG, SW FISK, Z AF ARONSON, MC DIERKER, SB DENNIS, BS CHEONG, SW FISK, Z TI PRESSURE-DEPENDENCE OF THE EXCHANGE INTERACTION IN LA2CUO4 SO PHYSICA B LA English DT Article; Proceedings Paper CT 19TH INTERNATIONAL CONF ON LOW TEMPERATURE PHYSICS ( LT-19 ) CY AUG 16-22, 1990 CL BRIGHTON, ENGLAND SP INT UNION PURE & APPL PHYS, OXFORD INSTRUMENTS, ELSEVIER NORTH HOLLAND PUBL, UNIV SUSSEX, INST PHYS, USAF, GEC ID FLUCTUATIONS AB We report the results of Raman scattering measurements which determine the pressure dependence of the inplane exchange coupling constant J in magnetic La2CuO4 for pressures between 1bar and 100 kbar. We find that pressure increases the Neel temperature T(N) much more rapidly than J. This result together with the theory for a quasi two-dimensional magnetic system then suggests that the interplanar exchange coupling decreases with pressure. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. AT&T BELL LABS,MURRAY HILL,NJ 07974. NR 11 TC 0 Z9 0 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD FEB PY 1991 VL 169 IS 1-4 BP 621 EP 622 DI 10.1016/0921-4526(91)90356-J PG 2 WC Physics, Condensed Matter SC Physics GA FL630 UT WOS:A1991FL63000160 ER PT J AU MORALES, F ESCUDERO, R HINKS, DG ZHENG, Y AF MORALES, F ESCUDERO, R HINKS, DG ZHENG, Y TI THE TEMPERATURE ENERGY-GAP EVOLUTION OF BA0.6K0.4BIO3 BY ELECTRON-TUNNELING SO PHYSICA B LA English DT Article; Proceedings Paper CT 19TH INTERNATIONAL CONF ON LOW TEMPERATURE PHYSICS ( LT-19 ) CY AUG 16-22, 1990 CL BRIGHTON, ENGLAND SP INT UNION PURE & APPL PHYS, OXFORD INSTRUMENTS, ELSEVIER NORTH HOLLAND PUBL, UNIV SUSSEX, INST PHYS, USAF, GEC AB We report tunneling experiments using sandwich type junctions, with superconducting bulk samples of Ba0.6K0.4Bi03 and evaporated thin film Sn counterelectrodes. The tunneling characteristics show the energy gap feature, and structure in the d2I/dV2 curves. The results demonstrate that the temperature energy gap variation follows a BCS behavior. The ratio 2-DELTA/k(B)T(c) is 3.75 suggesting an intermediate coupling. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60459. RP MORALES, F (reprint author), NATL AUTONOMOUS UNIV MEXICO,INST INVEST MAT,APDO POSTAL 70-360,MEXICO CITY 04510,DF,MEXICO. NR 5 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD FEB PY 1991 VL 169 IS 1-4 BP 705 EP 706 DI 10.1016/0921-4526(91)90398-X PG 2 WC Physics, Condensed Matter SC Physics GA FL630 UT WOS:A1991FL63000202 ER PT J AU EMERY, VJ AF EMERY, VJ TI SOME ASPECTS OF THE THEORY OF HIGH-TEMPERATURE SUPERCONDUCTORS SO PHYSICA B-CONDENSED MATTER LA English DT Article ID MUON SPIN ROTATION; T-J MODEL; PHASE-SEPARATION; NORMAL-STATE; HUBBARD-MODEL; GROUND-STATE; OXIDES; LA2CUO4+DELTA; LA2-XSRXCUO4; TRANSITION AB A qualitative survey of the theory of high-temperature superconductors as strongly correlated electron systems is presented. Various microscopic models and their implications for the theory of the normal state are described. Constraints on the mechanism and many-body theory of the superconducting state are discussed. RP EMERY, VJ (reprint author), BROOKHAVEN NATL LAB, DEPT PHYS, UPTON, NY 11973 USA. NR 58 TC 16 Z9 16 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD FEB PY 1991 VL 169 IS 1-4 BP 17 EP 25 DI 10.1016/0921-4526(91)90202-P PG 9 WC Physics, Condensed Matter SC Physics GA FL630 UT WOS:A1991FL63000006 ER PT J AU RAMESH, R RAVI, TS HWANG, DM CHANG, CC INAM, A VENKATESAN, T WU, XD MUENCHAUSEN, RE FOLTYN, S NOGAR, NS AF RAMESH, R RAVI, TS HWANG, DM CHANG, CC INAM, A VENKATESAN, T WU, XD MUENCHAUSEN, RE FOLTYN, S NOGAR, NS TI MICROSTRUCTURAL EVOLUTION OF LASER DEPOSITED SUPERCONDUCTING Y-BA-CU-O FILMS - EFFECT OF DEPOSITION RATE SO PHYSICA C LA English DT Article ID SRTIO3 AB The microstructure of laser deposited, superconducting Y-Ba-Cu-O thin films grown on [001] SrTiO3 substrates has been characterized as a function of laser pulse rate. Over a range of deposition rates from 1-150 angstrom/s, the films consist mainly of the c-axis oriented epitaxial, YBa2Cu3O7-x phase with a high density of polytypoidic stacking defects. High transport critical current densities, J(c), are attributed to the retention of the primarily c-axis oriented microstructure along with the distribution of stacking defects that provide good flux pinning. At higher deposition rates we observe new growth directions, specifically the a,b-axis and the [103] growth directions are favored. We conclude that within the deposition rate range of 1-150 angstrom/s, there is no significant fundamental change in microstructure except for outgrowth formation. Therefore, we are optimistic that much higher rates can be attained in the near future, although controlling the outgrowth formation may be difficult. C1 RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. UNIV CALIF LOS ALAMOS SCI LAB,ERDC,LOS ALAMOS,NM 87545. RP RAMESH, R (reprint author), BELLCORE,RED BANK,NJ 07701, USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 16 TC 22 Z9 22 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 1 PY 1991 VL 173 IS 3-4 BP 163 EP 172 DI 10.1016/0921-4534(91)90364-5 PG 10 WC Physics, Applied SC Physics GA EY245 UT WOS:A1991EY24500006 ER PT J AU YAMADA, Y JORGENSEN, JD PEI, S LIGHTFOOT, P KODAMA, Y MATSUMOTO, T IZUMI, F AF YAMADA, Y JORGENSEN, JD PEI, S LIGHTFOOT, P KODAMA, Y MATSUMOTO, T IZUMI, F TI STRUCTURAL-CHANGES OF SUPERCONDUCTING YBA2CU4O8 UNDER HIGH-PRESSURE SO PHYSICA C LA English DT Article ID TEMPERATURE; 80-K; ANOMALIES; TC AB Structural changes in YBa2Cu4O8 have been studied as a function of pressure using TOF neutron powder diffraction with a sample in a helium-gas pressure cell. Its structure contains double chains of edge-sharing [CuO4] squares and two-dimensional CuO2 planes. The distance between an apical oxygen atom and an in-plane copper atom decreases with increasing pressure. The distances between barium and oxygen atoms in the chain and between in-plane copper atoms located on both sides of a Y layer also change significantly with pressure. All of these movements of atoms are closely related to charge transfer from the CuO chain to the CuO2 plane. Calculation of Madelung energies based on our structural parameters shows that the concentration of holes in the conducting CuO2 plane increases appreciably with increasing pressure, which is in good agreement with the observed rise in T(c) under high pressure. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,ARGONNE,IL 60439. GOVT IND RES INST,KITA KU,NAGOYA,AICHI 462,JAPAN. NATL INST RES INORGAN MAT,TSUKUBA,IBARAKI 305,JAPAN. RP YAMADA, Y (reprint author), NATL RES INST MET,MAT PHYS,2-3-12 NAKAMEGURO,MEGURO KU,TOKYO 153,JAPAN. NR 26 TC 110 Z9 110 U1 3 U2 13 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 1 PY 1991 VL 173 IS 3-4 BP 185 EP 194 DI 10.1016/0921-4534(91)90367-8 PG 10 WC Physics, Applied SC Physics GA EY245 UT WOS:A1991EY24500009 ER PT J AU MOHAGHEGHI, AH BRYANT, HC HARRIS, PG REEDER, RA SHARIFIAN, H TANG, CY TOOTOONCHI, H QUICK, CR COHEN, S SMITH, WW STEWART, JE AF MOHAGHEGHI, AH BRYANT, HC HARRIS, PG REEDER, RA SHARIFIAN, H TANG, CY TOOTOONCHI, H QUICK, CR COHEN, S SMITH, WW STEWART, JE TI INTERACTION OF RELATIVISTIC H- IONS WITH THIN FOILS SO PHYSICAL REVIEW A LA English DT Article ID PHOTODETACHMENT CROSS-SECTION; CARBON FOILS; STATES; IONIZATION; RESONANCES; THRESHOLD; TARGETS; ATOMS; FIELD AB The response of relativistic H- ions to thin carbon foils was investigated for beam energies ranging from 226 to 800 MeV. For the foil thicknesses studied, ranging from 15 to 300 mu-g/cm2, an appreciable fraction of the H- beam survives intact, some H- ions are stripped down to protons, and the remainder is distributed over the states of H(O). This experiment is different from the low-energy studies in that the projectile velocity is comparable to the speed of light, leading to an interaction time typically less than a femtosecond. The present results challenge the theoretical understanding of the interaction mechanisms. An electron spectrometer was used to selectively field ionize the Rydberg states 9 < n < 17 at beam energies of 581 and 800 MeV. The yield of low-lying states was measured by Doppler tuning a Nd:YAG (where YAG represents yttrium aluminum garnet) laser to excite transitions to a Rydberg state that was then field ionized and detected. Data are presented for production of n = 2,3 at 226 MeV, n = 2,3 at 500 MeV, n = 2,3,4 at 581 MeV, n = 2 at 716 MeV, and n = 1,2,3,4,5 at 800 MeV. A simple model is developed to fit the yield of each state as a function of foil thickness. Although the simple model is successful in predicting the general features, the data are suggestive of a more complex structure, in the yield of a state as a function of the foil thickness. The optimum thickness to produce a given state increases with the principal quantum number of the state, suggesting an excitation process that is at least partially stepwise. The results of a Monte Carlo simulation are compared with the experimental data to estimate the distribution of the excited states coming out of a foil. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV CONNECTICUT,STORRS,CT 06268. WESTERN WASHINGTON STATE UNIV,BELLINGHAM,WA 98225. CALIF STATE UNIV LONG BEACH,LONG BEACH,CA 90840. RP MOHAGHEGHI, AH (reprint author), UNIV NEW MEXICO,ALBUQUERQUE,NM 87131, USA. NR 40 TC 17 Z9 17 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB 1 PY 1991 VL 43 IS 3 BP 1345 EP 1365 DI 10.1103/PhysRevA.43.1345 PG 21 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800025 ER PT J AU VANEMMICHOVEN, PAZ HAVENER, CC MEYER, FW AF VANEMMICHOVEN, PAZ HAVENER, CC MEYER, FW TI NEUTRALIZATION OF HIGHLY CHARGED IONS AT GRAZING-INCIDENCE ON A METAL-SURFACE SO PHYSICAL REVIEW A LA English DT Article ID ELECTRON-EMISSION; SOLID-SURFACES; TUNGSTEN AB Electron energy spectra and total electron yields are studied to provide information on the neutralization of 24-keV N(q+) ions (q = 2,4,6) incident at grazing angles on a Cu(100) surface. A computer simulations of the neutralization is presented that assumes resonant neutralization of the ions leading to highly excited "hollow" atoms. Deexcitation of these atoms is assumed to take place by purely intra-atomic Auger transitions. The results of this stimulation are not in agreement with our experimental observations. A modified simulation, assuming again resonant neutralization of the ions followed by faster deexcitation processes, and, in addition, fast Auger deexcitation directly into the L shell, shows a much better agreement with the experiment observations. C1 HOLIFIELD HEAVY ION RES FACIL,JOINT INST HEAVY ION RES,OAK RIDGE,TN 37831. RP VANEMMICHOVEN, PAZ (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 24 TC 48 Z9 48 U1 1 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 FEB 1 PY 1991 VL 43 IS 3 BP 1405 EP 1415 DI 10.1103/PhysRevA.43.1405 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800030 ER PT J AU BOROVSKY, JE SUSZCYNSKY, DM AF BOROVSKY, JE SUSZCYNSKY, DM TI EXPERIMENTAL INVESTIGATION OF THE Z2 SCALING LAW OF FAST-ION-PRODUCED SECONDARY-ELECTRON EMISSION SO PHYSICAL REVIEW A LA English DT Review ID STOPPING POWER; CHARGED-PARTICLES; METAL TARGETS; ENERGY-LOSS; ATOMIC-NUMBER; LIQUID ARGON; MEV PROTONS; BOMBARDMENT; DEPENDENCE; IONIZATION AB The secondary-electron yields Y are measured for H-1(1+), He-3(2+), He-4(2+), Be-9(4+), B-10(5+), C-12(6+), and O-16(8+) ions with 1.5-11 MeV/amu of kinetic energy hitting gold, aluminum oxide, and tantalum targets. For such fast ions, it is expected that the yield will scale as Y proportional to z2, where z is the charge state of the ion. The yield data are reduced to remove the kinetic-energy dependence and it is found that Y proportional to z1.71 for gold targets, Y proportional to z1.62 for Al2O3 targets, and Y proportional to z1.72 for tantalum targets. Reasons for the deviation of the data from the expected Y proportional to z2 scaling law are explored. The electric fields arising from space-charge separations in the wakes of the fast ions are suspected to be the cause of the lowered scaling law. RP BOROVSKY, JE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,SPACE PLASMA PHYS GRP,LOS ALAMOS,NM 87545, USA. NR 116 TC 33 Z9 33 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB 1 PY 1991 VL 43 IS 3 BP 1416 EP 1432 DI 10.1103/PhysRevA.43.1416 PG 17 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800031 ER PT J AU BOROVSKY, JE SUSZCYNSKY, DM AF BOROVSKY, JE SUSZCYNSKY, DM TI REDUCTION OF SECONDARY-ELECTRON YIELDS BY COLLECTIVE ELECTRIC-FIELDS WITHIN METALS SO PHYSICAL REVIEW A LA English DT Article ID FAST MOLECULAR-IONS; SWIFT IONS; TARGETS; SOLIDS; PROJECTILES; PARTICLES; EMISSION; PLASMA; GOLD AB A fast ion passing through a metal target drives electrons out of its path by means of Coulomb scattering. Some of these electrons escape the target and are denoted as secondary electrons. The rapid displacement of electrons from the ion's path produces a charge separation in the metal, which gives rise to an electric field in the wake of the ion. For z > 1 ions, the wake fields can be so strong that the retard the movement of electrons away from the ion's path, which reduces the number of secondary electrons that escape the target. The time-dependent electric fields behind fast ions in metals are modeled and the motion of Coulomb-scattered electrons in these fields is examined. The fraction of the electrons that are trapped by the wake is estimated and from this the reduction in the yield of secondary electrons is quantified. The results are in agreement with measurements of secondary-electron emission by fast, high-z ions hitting metal targets. RP BOROVSKY, JE (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,SPACE PLASMA PHYS GRP,LOS ALAMOS,NM 87545, USA. NR 36 TC 31 Z9 31 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 FEB 1 PY 1991 VL 43 IS 3 BP 1433 EP 1440 DI 10.1103/PhysRevA.43.1433 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800032 ER PT J AU BAND, YB ACKERHALT, JR KRASINSKI, JS AF BAND, YB ACKERHALT, JR KRASINSKI, JS TI SPECTRAL-ANALYSIS OF INTRACAVITY 2ND-HARMONIC GENERATION IN A RING LASER SO PHYSICAL REVIEW A LA English DT Article ID ND-YAG LASERS AB Studies of the spectral content and stability of an intracavity second-harmonic ring laser show that single-mode cw operation is stable against amplitude-modulated fluctuations, whereas frequency-modulated fluctuations are undamped. cw operation tends to single longitudinal mode output under very general conditions provided frequency modulation is not introduced. Multimode frequency-modulated cw operation can be achieved. Methods for producing an anti-mode-locked laser and a frequency-modulated laser are described. However, the presence of an intracavity spectral filter will remove frequency modulation. The importance of a spectral filter to restrict the fundamental frequency to the phase-matched bandwidth of the doubler is emphasized. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. ALLIED SIGNAL INC,CTR CORP TECHNOL,MORRISTOWN,NJ 07960. RP BAND, YB (reprint author), BEN GURION UNIV NEGEV,DEPT CHEM,IL-84105 BEER SHEVA,ISRAEL. NR 22 TC 1 Z9 1 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD FEB 1 PY 1991 VL 43 IS 3 BP 1528 EP 1537 DI 10.1103/PhysRevA.43.1528 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800045 ER PT J AU HAAS, RA ROTTER, MD AF HAAS, RA ROTTER, MD TI THEORY OF PULSED DYE-LASERS INCLUDING DYE-MOLECULE ROTATIONAL RELAXATION SO PHYSICAL REVIEW A LA English DT Article ID AMPLIFIED SPONTANEOUS EMISSION; FLUORESCENCE QUANTUM YIELDS; POLARIZATION CHARACTERISTICS; SPECTRAL PROPERTIES; OPTICAL PULSES; STATE; AMPLIFICATION; DISTRIBUTIONS; RHODAMINE-6G; LIGHT AB In this paper a phenomenological semiclassical theory of pulsed-laser-pumped dye-laser light amplifiers is presented. The theory accounts for the broadband radiation absorption and emission characteristics of dye molecules in liquid solvents. Dye-molecule fluorescence, vibrational, rotational, and electric polarization relaxation processes are represented by phenomenological relaxation rates. In general, it is found that due to dye-molecule rotational relaxation the laser-pumped dye medium is optically anisotropic. The pump- and dye-laser beams propagate through the dye medium as essentially transverse electromagnetic waves whose amplitude and polarization state changes. The theory is applicable to pulse durations tau less-than-or-similar-to 10-100 ns including the ultrashort pulse regime. The regime tau greater-than-or-similar-to 1 ps in which the pump- and dye-laser pulse lengths are long compared to the dye-molecule vibrational and electric polarization relaxation times is considered in detail. Amplification of partially polarized quasimonochromatic light is described by a self-consistent set of equations for the components of the pump- and dye-laser light coherency matrices and the orientation populations of the lowest vibronic levels of the dye molecule's S0 and S1 electronic states. The interaction of the pump- and dye-laser beams with the dye molecules is characterized by complex electric susceptibility tensors. Kramers-Kronig or Hilbert transform relations are found that permit dye-molecule absorption and emission cross sections to be used to calculate the pump- and dye-laser susceptibility tensors. All the physical parameters in the theory may be determined by conventional experimental techniques. When the dye-molecule rotational relaxation rate gamma-R is much larger than the fluorescence rate gamma-F, tau-1, and the pump-laser absorption and dye-laser stimulated emission rates, then the dye-molecule electric susceptibility tensors are diagonal. The laser-pumped dye-laser medium is optically isotropic. When these conditions do not hold the medium is optically anisotropic and coherency matrices may be used to describe the propagation of the pump- and dye-laser beams. This procedure is illustrated for the case of transversely pumped dye lasers. In the small-signal regime analytic solutions for the dye-laser-light coherence matrix components are developed for arbitrary initial polarization state, pulse duration, and gamma-F/gamma-R. In the large-signal regime numerical solutions are obtained for the amplification of short, (tau-gamma-F, tau-gamma-R)<< 1, and quasi-steady-state (tau-gamma-F,tau-gamma-R)>> 1, pulses for arbitrary values of gamma-F/gamma-R when the pump- and dye-laser polarizations are parallel. In general, it is found that for a wide range of physical conditions of interest dye-molecule rotational relaxation is important, and significant changes in the amplification characteristics of the medium, i.e., the rate of amplification, amplification efficiency, and polarization state of the light, will occur. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RP HAAS, RA (reprint author), UNIV CALIF DAVIS LIVERMORE,DEPT APPL SCI,L-794,POB 808,LIVERMORE,CA 94550, USA. NR 61 TC 14 Z9 14 U1 0 U2 8 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 FEB 1 PY 1991 VL 43 IS 3 BP 1573 EP 1603 DI 10.1103/PhysRevA.43.1573 PG 31 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800049 ER PT J AU ZAJFMAN, D KANTER, EP VAGER, Z ZAJFMAN, J AF ZAJFMAN, D KANTER, EP VAGER, Z ZAJFMAN, J TI SENSITIVITY OF COULOMB-EXPLOSION IMAGES TO THE SHAPES OF MOLECULAR POTENTIALS - THE CASE OF HE2(2+) SO PHYSICAL REVIEW A LA English DT Note ID STATES; ENERGIES; HE-2(2+) AB A quantitative analysis of the results of a recent Coulomb-explosion experiment with He-2(2+) is described. Using the adiabatic potential curve predicted for the 1-SIGMA-g+ ground state of this relatively simple dication, a Monte Carlo simulation of the Coulomb-explosion process was performed. The results show that such methods can faithfully reproduce the experimental results when accurate potential-energy surfaces are available. The implications for more complex systems are discussed. RP ZAJFMAN, D (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 17 TC 11 Z9 11 U1 1 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 FEB 1 PY 1991 VL 43 IS 3 BP 1608 EP 1610 DI 10.1103/PhysRevA.43.1608 PG 3 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800051 ER PT J AU RESCIGNO, TN OREL, AE AF RESCIGNO, TN OREL, AE TI CONTINUUM BASIS FUNCTIONS IN THE COMPLEX KOHN VARIATIONAL METHOD SO PHYSICAL REVIEW A LA English DT Note ID ELECTRON-MOLECULE COLLISIONS; POLYATOMIC-MOLECULES; QUANTUM SCATTERING; PRINCIPLE AB We propose a different way for selecting the outgoing continuum basis functions needed in complex Kohn variational calculations of electron-molecule scattering. The proposed method is based on the recent work of Sun et al. [Phys. Rev. A 41, 4857 (1990)] dealing with dynamically prepared basis sets for algebraic variational calculations. We have found an alternative technique for removing the sensitivity to the traditional cutoff function in calculations involving ionic targets, while retaining all the computational simplicity of the complex Kohn method. C1 UNIV CALIF DAVIS,DEPT APPL SCI,LIVERMORE,CA 94550. RP RESCIGNO, TN (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 22 TC 29 Z9 29 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 FEB 1 PY 1991 VL 43 IS 3 BP 1625 EP 1628 DI 10.1103/PhysRevA.43.1625 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EX008 UT WOS:A1991EX00800056 ER PT J AU BARRETT, JH OEN, OS HOLLAND, OW AF BARRETT, JH OEN, OS HOLLAND, OW TI FURTHER ASPECTS OF ENHANCED ION-SCATTERING NEAR 180-DEGREES SO PHYSICAL REVIEW B LA English DT Article ID BACKSCATTERING; REVERSIBILITY AB The role of rainbow scattering in enhanced ion scattering near 180-degrees was explored by comparing calculated enhancements for protons and antiprotons. Since the rainbow effect does not occur for negative particles and since the enhancement was much smaller for them than for positive particles, this comparison demonstrated in a more direct way than previously done the importance of rainbow scattering in producing the enhancement. A procedure for calculating a similarity factor between the ingoing and outgoing portions of a trajectory was developed, and its use showed that trajectories returning near 180-degrees differ in nature from random-return trajectories. A discussion is given of the possible relationship of the enhancement to phenomena such as the correlation effect in self-diffusion by the vacancy mechanism in solids and surface-structure studies by impact-collision ion-scattering spectrometry. RP BARRETT, JH (reprint author), OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831, USA. NR 14 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 2471 EP 2476 DI 10.1103/PhysRevB.43.2471 PN A PG 6 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300001 ER PT J AU YETHIRAJ, M ROBINSON, RA SIVIA, DS LYNN, JW MOOK, HA AF YETHIRAJ, M ROBINSON, RA SIVIA, DS LYNN, JW MOOK, HA TI NEUTRON-SCATTERING STUDY OF THE MAGNON ENERGIES AND INTENSITIES IN IRON SO PHYSICAL REVIEW B LA English DT Article ID CONSTANT-Q SPECTROMETER; MAGNETIC EXCITATIONS; FERROMAGNETIC IRON AB The magnetic inelastic neutron scattering at low temperatures has been measured from a large single crystal of Fe-54(12 at. % Si) up to energy transfers of 100 meV using the constant-Q spectrometer at the Los Alamos pulsed neutron source. The spin-wave energies and intensities were obtained from the data by using a multichannel maximum-entropy technique, and we show that much more detailed information can be obtained from the maximum-entropy analysis. The observed spin-wave dispersion relations obtained in the present experiment are in excellent agreement with earlier data, and we observe a sharp falloff of the (001) magnon intensity at approximately 80 meV, which is in accord with previous experimental measurements and multiband theoretical calculations of the dynamic susceptibility of iron. We also compare the data rate obtained with the constant-Q spectrometer to a triple-axis instrument and find that the spectrometer is competitive for this type of measurement. C1 UNIV MARYLAND,DEPT PHYS,COLLEGE PK,MD 20742. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP YETHIRAJ, M (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,MANUEL J LUJAN JR NEUTRON SCATTERING CTR,LOS ALAMOS,NM 87545, USA. NR 28 TC 7 Z9 7 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 1 PY 1991 VL 43 IS 4 BP 2565 EP 2574 DI 10.1103/PhysRevB.43.2565 PN A PG 10 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300011 ER PT J AU DAEMEN, LL GUBERNATIS, JE AF DAEMEN, LL GUBERNATIS, JE TI NUMERICAL COMPUTATION OF THE FLUX-LINE-LATTICE STRUCTURE OF AN INHOMOGENEOUS MATERIAL IN THE LONDON APPROXIMATION SO PHYSICAL REVIEW B LA English DT Article ID II SUPERCONDUCTORS; COMPUTER-SIMULATION AB We present the basic equations that permit the efficient simulation of vortex structures in inhomogeneous materials whose superconducting behavior is described by the London equations. In analogy to homogeneous materials, we show that the energy of such structures is the sum of a self-interaction part, which depends on the local variation of the penetration depth, and a sum of pair interactions, which are the Green's functions of the London equation for an inhomogeneous material. This formalism permits simulations in which the exact, long-range London interactions between flux lines are used. In addition, the realistic modeling of defects by allowing the penetration depth to vary spatially is possible, and pinning, instead of being assumed, arises in a natural manner by local variations in Lorentz forces. The equations were solved for a variety of one-dimensional models of inhomogeneities, and physically reasonable flux-line lattices were found. A suggestion for the use of the formalism to study the dynamic properties of flux-line lattices is made. RP DAEMEN, LL (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Lujan Center, LANL/G-4896-2012 NR 15 TC 8 Z9 8 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 1 PY 1991 VL 43 IS 4 BP 2625 EP 2632 DI 10.1103/PhysRevB.43.2625 PN A PG 8 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300017 ER PT J AU EMIN, D AF EMIN, D TI ORBITAL MAGNETISM OF SINGLET LARGE BIPOLARONS SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTIVITY; YBA2CU3O7 AB Despite having no spin magnetism, a singlet large bipolaron in an anisotropic environment has a large anisotropic Van Vleck orbital paramagnetism. With the dislike large-bipolaron morphology envisioned for layered structures, the induced moment is aligned within the planes. The paramagnetic susceptibility and magnetic excitations of large bipolarons are suppressed in the condensate of interacting large bipolarons. Thus, carrier-related shifts of NMR frequencies and spin-lattice relaxation rates progressively fall as the temperature is lowered below T(c). RP EMIN, D (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 13 TC 3 Z9 3 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 2633 EP 2636 DI 10.1103/PhysRevB.43.2633 PN A PG 4 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300018 ER PT J AU KRESIN, VZ MORAWITZ, H AF KRESIN, VZ MORAWITZ, H TI ELECTRON-ENERGY-LOSS SPECTROSCOPY OF LAYERED SYSTEMS SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; CU-O SYSTEM; SEMICONDUCTOR SUPERLATTICE; COLLECTIVE EXCITATIONS; GAS; PRESSURE; PLASMONS AB A feature of electron-energy-loss spectroscopy (EELS) in layered materials is predicted. Contrary to the usual isotropic case, EELS becomes temperature dependent. This result, obtained by using thermodynamic Green's functions, arises from the unusual structure of the layer plasmon bands. C1 IBM CORP,ALMADEN RES CTR,DIV RES,SAN JOSE,CA 95120. RP KRESIN, VZ (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM PHYS,BERKELEY,CA 94720, USA. NR 41 TC 4 Z9 4 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 FEB 1 PY 1991 VL 43 IS 4 BP 2691 EP 2695 DI 10.1103/PhysRevB.43.2691 PN A PG 5 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300026 ER PT J AU ALLEN, PB AF ALLEN, PB TI MODEL FOR AN EXTRA PHONON MODE IN LA2CUO4 AND LA2NIO4 SO PHYSICAL REVIEW B LA English DT Article ID LATTICE-DYNAMICS; EXCITATIONS AB Phonon dispersion curves for two-dimensional analogs of La2CuO4 and La2NiO4 are modeled by adding a scalar degree of freedom to mimic a low-lying charge-fluctuation mode. The resulting model bears a close resemblance to the "extra phonon mode" seen in neutron scattering by Pintschovius et al. In particular, the mode is invisible to neutrons at Q = 0 because scalar symmetry prevents admixture with vibrational modes at Q = 0. Possible interpretations of this new mode are suggested. C1 SUNY STONY BROOK,DEPT PHYS,STONY BROOK,NY 11794. RP ALLEN, PB (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,MS K765,LOS ALAMOS,NM 87545, USA. NR 32 TC 5 Z9 5 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 1 PY 1991 VL 43 IS 4 BP 2766 EP 2770 DI 10.1103/PhysRevB.43.2766 PN A PG 5 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300038 ER PT J AU CAMPUZANO, JC SMEDSKJAER, LC BENEDEK, R JENNINGS, G BANSIL, A AF CAMPUZANO, JC SMEDSKJAER, LC BENEDEK, R JENNINGS, G BANSIL, A TI FERMI-SURFACE IN YBA2CU3O6.9 - EVIDENCE FROM ANGLE-RESOLVED PHOTOEMISSION SPECTROSCOPY AND POSITRON 2-DIMENSIONAL ANGULAR-CORRELATION OF ANNIHILATION RADIATION SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TC SUPERCONDUCTORS; ANDERSON LATTICE MODEL; ELECTRONIC-STRUCTURE; NORMAL STATE; CU-O; YBA2CU3O7-DELTA; DENSITY; BAND; GAP AB We assess the evidence regarding the geometry of the Fermi surface in YBa2Cu3O6.9 obtained from angle-resolved photoemission and positron two-dimensional angular correlation of annihilation radiation experiments. A detailed picture of the Fermi-surface topology of this system appears to be emerging, based on a comparison of the above-mentioned experiments with each other and with local-density-approximation calculations, although whether the Fermi surface is a manifestation of true Fermi-liquid behavior is in dispute. Some implications of these results are discussed. C1 UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60680. NORTHEASTERN UNIV,DEPT PHYS,BOSTON,MA 02115. RP CAMPUZANO, JC (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Campuzano, Juan Carlos/G-4358-2012 NR 58 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 FEB 1 PY 1991 VL 43 IS 4 BP 2788 EP 2795 DI 10.1103/PhysRevB.43.2788 PN A PG 8 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300042 ER PT J AU HAO, ZD CLEM, JR MCELFRESH, MW CIVALE, L MALOZEMOFF, AP HOLTZBERG, F AF HAO, ZD CLEM, JR MCELFRESH, MW CIVALE, L MALOZEMOFF, AP HOLTZBERG, F TI MODEL FOR THE REVERSIBLE MAGNETIZATION OF HIGH-KAPPA TYPE-II SUPERCONDUCTORS - APPLICATION TO HIGH-TC SUPERCONDUCTORS SO PHYSICAL REVIEW B LA English DT Article ID UPPER CRITICAL-FIELD; SINGLE-CRYSTALS AB A simple theoretical model is proposed for the reversible magnetization of type-II superconductors as a function of the applied field H for the entire field region between H(c1) and H(c2). For H congruent-to H(c1), the theory reduces to a variational model, from which H(c1) can be accurately computed in the Ginzburg-Landau regime. In calculating the free energy, we include, in addition to the super-current kinetic energy and the magnetic-field energy, the kinetic-energy and the condensation-energy terms arising from suppression of the order parameter in the vortex core. The model is further extended to include anisotropy by introducing an effective-mass tensor for the case when H is parallel to one of the principal axes. The theory is compared to reversible-magnetization data on a YBa2Cu3O7 single crystal. The method permits an accurate determination of H(c2) versus temperature from measurements of the magnetization versus temperature at fixed magnetic field and explains why the measurements have different slopes in different fields, contrary to what might have been expected from the linear Abrikosov formula near H(c2). The deduced dH(c2)/dT is (-1.65 +/- 0.23) T/K for H parallel to the c axis near T(c), implying xi-ab(0) = (17 +/- 1) angstrom. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. RP HAO, ZD (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. NR 37 TC 329 Z9 331 U1 3 U2 18 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 2844 EP 2852 DI 10.1103/PhysRevB.43.2844 PN A PG 9 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300048 ER PT J AU KIM, DH GRAY, KE KAMPWIRTH, RT MCKAY, DM AF KIM, DH GRAY, KE KAMPWIRTH, RT MCKAY, DM TI MAGNETOCONDUCTANCE OF TL2BA2CACU2OX FILMS IN THE FLUCTUATION REGIME SO PHYSICAL REVIEW B LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; UPPER CRITICAL-FIELD; MAGNETIC-FIELD; PAIR-BREAKING; TC; MAGNETORESISTANCE; YBA2CU3O7-X; CONDUCTIVITY; RESISTANCE; TRANSITION AB Magnetoconductance (MC) has been measured above the mean-field transition temperature T(c) in the highly anisotropic high-temperature superconductor Tl2Ba2CaCu2O(x) for fields parallel and perpendicular to the CuO plane. Recent theoretical expressions for the magnetoconductance in the layered superconductors provide a good fit for the temperature range T(c) + 10 K < T < 160 K. Using the additional constraint of the zero-field fluctuation conductivity, we obtain the in-plane coherence length xi-ab(0) almost-equal-to 11.8 +/- 0.4 angstrom and a linear temperature dependence for the phase relaxation rate, with 1/tau-phi-almost-equal-to (3.5 +/- 0.5) X 10(13) sec-1 at T(c). For T(c) < T < T(c) + 10 K, we found a significant enhancement of the negative MC compared to the prediction based on the Gaussian approximation. A possible origin of such deviation is discussed. RP KIM, DH (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. NR 27 TC 22 Z9 23 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 2910 EP 2915 DI 10.1103/PhysRevB.43.2910 PN A PG 6 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300056 ER PT J AU MAHAN, GD AF MAHAN, GD TI POLARONS IN THE LAYERED ELECTRON-GAS SO PHYSICAL REVIEW B LA English DT Article ID LIFETIME AB In a layered electron gas, optical phonons which vibrate with their polarization parallel to the c axis are relatively unscreened when the conduction electrons can move only within the planes. We calculate the electron-phonon interaction between the conduction electrons and these parallel phonons. We show that the interaction is very weak. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. RP MAHAN, GD (reprint author), UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996, USA. NR 15 TC 0 Z9 0 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 2934 EP 2939 DI 10.1103/PhysRevB.43.2934 PN A PG 6 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300059 ER PT J AU WEIR, ST NELLIS, WJ DALICHAOUCH, Y LEE, BW MAPLE, MB LIU, JZ SHELTON, RN AF WEIR, ST NELLIS, WJ DALICHAOUCH, Y LEE, BW MAPLE, MB LIU, JZ SHELTON, RN TI EVIDENCE FOR A TIME-DEPENDENT CROSSOVER FROM SURFACELIKE TO BULK-LIKE FLUX RELAXATION IN YBA2CU3O7-DELTA SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTORS; CRYSTAL; MOTION; CREEP AB dc flux-relaxation experiments were performed on single crystals of YBa2Cu3O7-delta at low magnetic fields. A sharp, time-dependent crossover in the logarithmic magnetization decay rate was observed in two different crystals. Consideration of the size dependence of the relaxation rate in one of the YBa2Cu3O7-delta crystals suggests that the crossover in the relaxation rate is due to a transition from surface-controlled to bulk-controlled relaxation behavior. Our observations seem to indicate that, over a certain range of temperatures and magnetic fields, surface pinning may play a significant role in the flux-relaxation behavior of YBa2Cu3O7-delta. C1 UNIV CALIF SAN DIEGO,LA JOLLA,CA 92093. UNIV CALIF DAVIS,DAVIS,CA 95616. RP WEIR, ST (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. RI Weir, Samuel/H-5046-2012 NR 23 TC 28 Z9 28 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 1 PY 1991 VL 43 IS 4 BP 3034 EP 3041 DI 10.1103/PhysRevB.43.3034 PN A PG 8 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300071 ER PT J AU SAUERZOPF, FM WIESINGER, HP KRITSCHA, W WEBER, HW CRABTREE, GW LIU, JZ AF SAUERZOPF, FM WIESINGER, HP KRITSCHA, W WEBER, HW CRABTREE, GW LIU, JZ TI NEUTRON-IRRADIATION EFFECTS ON CRITICAL CURRENT DENSITIES IN SINGLE-CRYSTALLINE YBA2CU3O7-DELTA SO PHYSICAL REVIEW B LA English DT Article ID SUPERCONDUCTORS; DAMAGE; MAGNETIZATION AB Neutron-irradiation experiments were made on two high-quality YBa2Cu3O7-delta single crystals in the fluence range from 2 X 10(21) to 2 X 10(22) m-2 (E > 0.1 MeV). Critical current densities J(c) and volume-pinning forces P(V) were obtained from magnetization measurements in the temperature range from 5 to 77 K, for magnetic fields up to 8 T, and for field orientations parallel and perpendicular to the crystallographic c direction. All evaluations were made on the basis of an extended anisotropic Bean model. The results show large enhancements of flux pinning, in particular at low neutron fluences, a strong reduction of J(c) anisotropy, and significant changes of the temperature dependence of J(c). The complicated (nonlinear) dependence of critical current densities and pinning forces on neutron fluence is discussed in terms of an interaction between the radiation-induced defects with the preirradiation defect structure, based on electron microscopy of individual defects and the defect distribution measured in one crystal after neutron irradiation to 2 X 10(22) m-2 (E > 0.1 MeV). C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. UNIV CALIF DAVIS,DEPT PHYS,DAVIS,CA 95616. RP SAUERZOPF, FM (reprint author), UNIV VIENNA,INST ATOM,A-1020 VIENNA,AUSTRIA. NR 43 TC 92 Z9 93 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 1 PY 1991 VL 43 IS 4 BP 3091 EP 3100 DI 10.1103/PhysRevB.43.3091 PN A PG 10 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300078 ER PT J AU ERIKSSON, O ALBERS, RC BORING, AM FERNANDO, GW HAO, YG COOPER, BR AF ERIKSSON, O ALBERS, RC BORING, AM FERNANDO, GW HAO, YG COOPER, BR TI SURFACE ELECTRONIC-STRUCTURE OF CE IN THE ALPHA AND GAMMA-PHASE SO PHYSICAL REVIEW B LA English DT Article ID GROUND-STATE PROPERTIES; CERIUM METAL; TRANSITION; PHOTOEMISSION; SPECTROSCOPY; PRESSURE; DENSITY AB The surface electronic structure of Ce in the alpha and gamma-phase has been calculated using' a film linearized-muffin-tin-orbitals method. The bonding in Ce is found to be mainly metallic in character. The width of the 4f band in alpha-Ce is found to be about 0.7 eV both in the bulk and at the surface; in gamma-Ce it is slightly narrower, about 0.6 eV. The calculated work function of alpha-Ce is in good agreement with experimental data. Cross sections for the bremsstrahlung isochromat (BIS) processes have been calculated in a fully relativistic framework, and good agreement with experiment is obtained for the itinerant peak in the BIS data near E(F). We find our results consistent with an itinerant f-electron picture for alpha-Ce, and thereby consistent with a picture for the gamma --> alpha-transition that is from localized (and magnetic) to itinerant (bonding and nonmagnetic) f-electron behavior, i.e., a Mott transition, as opposed to a Kondo volume collapse picture involving a transition between localized states of the f electrons. We also predict that the surface of alpha-cerium is gamma-like. C1 BROOKHAVEN NATL LAB,UPTON,NY 11973. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. W VIRGINIA UNIV,DEPT PHYS,MORGANTOWN,WV 26506. RP ERIKSSON, O (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. RI Eriksson, Olle/E-3265-2014 OI Eriksson, Olle/0000-0001-5111-1374 NR 36 TC 29 Z9 29 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 3137 EP 3142 DI 10.1103/PhysRevB.43.3137 PN A PG 6 WC Physics, Condensed Matter SC Physics GA FF083 UT WOS:A1991FF08300082 ER PT J AU FERNANDEZBACA, JA NICKLOW, RM TUN, Z RHYNE, JJ AF FERNANDEZBACA, JA NICKLOW, RM TUN, Z RHYNE, JJ TI NEUTRON-SCATTERING STUDY OF THE MAGNETIC EXCITATIONS OF THULIUM METAL SO PHYSICAL REVIEW B LA English DT Article AB We have performed neutron-scattering experiments to study the magnetic excitations of Tm in its low-temperature ferrimagnetic-antiphase-domain (FAD) phase. Our measurements confirm our earlier finding that the excitation spectrum of Tm in its FAD phase consists of one magnon mode with limited dispersion (8.3-9.6 meV). This result suggests that the Hamiltonian is dominated by the crystal-field-anistropy energy and that the exchange interaction is relatively weak. Two additional lower-energy excitations have also been observed, and they have been identified as originating from magnetovibrational scattering from the TA phonon. C1 OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. ATOM ENERGY CANADA LTD,CHALK RIVER NUCL LABS,CHALK RIVER K0J 1J0,ONTARIO,CANADA. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RI Fernandez-Baca, Jaime/C-3984-2014 OI Fernandez-Baca, Jaime/0000-0001-9080-5096 NR 12 TC 7 Z9 7 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 FEB 1 PY 1991 VL 43 IS 4 BP 3188 EP 3191 DI 10.1103/PhysRevB.43.3188 PN B PG 4 WC Physics, Condensed Matter SC Physics GA FF086 UT WOS:A1991FF08600007 ER PT J AU KIVSHAR, YS AF KIVSHAR, YS TI SOLITONS IN A NONLINEAR ELASTIC MEDIUM SO PHYSICAL REVIEW B LA English DT Article ID ENVELOPE AB The influence of nonlinearity on shear horizontal elastic (bulk and surface) waves in crystals is considered on the basis of a nonlinear equation derived from a microscopic scalar model. The continuum limit is compared with the equation obtained in the framework of nonlinear elasticity theory. Using the equation, it is demonstrated that nonlinear surface waves of the shear horizontal polarization are modulationally unstable, and, therefore, they have to produce surface solitary waves. The solitons are studied in the case of a nonlinear elastic plate when the effective asymptotic technique may be elaborated. In the main approximation of the asymptotic approach, the effective nonlinear Schrodinger equation is derived. We predict that in the nonlinear elastic plate it is possible to observe bright or dark envelope solitons that propagate without distortion. The properties of the solitons depend on the carrier wave number and the thickness of the plate. We demonstrate also that there is a discrete set of the solitons produced by linear modes of the elastic plate. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. NR 17 TC 13 Z9 13 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 FEB 1 PY 1991 VL 43 IS 4 BP 3493 EP 3499 DI 10.1103/PhysRevB.43.3493 PN B PG 7 WC Physics, Condensed Matter SC Physics GA FF086 UT WOS:A1991FF08600045 ER PT J AU YOU, H WELP, U FANG, Y AF YOU, H WELP, U FANG, Y TI SLOPE DISCONTINUITY AND FLUCTUATION OF LATTICE EXPANSION NEAR TC IN UNTWINNED YBA2CU3O7-DELTA SINGLE-CRYSTALS SO PHYSICAL REVIEW B LA English DT Note ID SUPERCONDUCTING TRANSITION; PHASE-TRANSITIONS; TEMPERATURE; ANOMALIES; MODES; HEAT AB The thermal lattice expansion of untwinned YBa2Cu3O7-delta single crystals is measured from 10 to 300 K with a high-resolution x-ray-diffraction technique on beam-line X22B at the National Synchrotron Light Source. All the unit-cell parameters (a, b, c, and volume) show unexpectedly large slope discontinuities near T(c) and possible strong fluctuations over a wide temperature region (80 < T < 120 K). Possible implications for the nature of the superconducting mechanism are discussed. C1 ARGONNE NATL LAB,SCI & TECHNOL CTR SUPERCOND,ARGONNE,IL 60439. RP YOU, H (reprint author), ARGONNE NATL LAB,DIV MAT SCI,9700 S CASS AVE,ARGONNE,IL 60439, USA. RI You, Hoydoo/A-6201-2011 OI You, Hoydoo/0000-0003-2996-9483 NR 34 TC 54 Z9 54 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 1 PY 1991 VL 43 IS 4 BP 3660 EP 3663 DI 10.1103/PhysRevB.43.3660 PN B PG 4 WC Physics, Condensed Matter SC Physics GA FF086 UT WOS:A1991FF08600069 ER PT J AU BANSIL, A MIJNARENDS, PE SMEDSKJAER, LC AF BANSIL, A MIJNARENDS, PE SMEDSKJAER, LC TI FERMI-SURFACE AND ELECTRON-POSITRON MOMENTUM DENSITY IN YBA2CU3O7 SO PHYSICAL REVIEW B LA English DT Note ID OXIDE SUPERCONDUCTORS; ANNIHILATION AB By folding the local-density-approximation (LDA) band-theory-based electron-positron momentum density into the first Brillouin zone, we find that signatures from all the Fermi-surface sheets can be obtained in YBa2Cu3O7, including in particular the Cu-O plane sheets. Our theoretical predictions appear to be in reasonable overall accord with the corresponding measurements by positron-annihilation two-dimensional angular correlation of annihilation radiation (2D-ACAR) of Smedskjaer et al., which have been interpreted in terms of Fermi surfaces. The Cu-O chain-related (electron) states appear to be substantially modified from LDA predictions. However, no firm conclusions concerning the existence of the Fermi surface in YBa2Cu3O7 can at the moment be drawn, since the experimental 2D-ACAR situation in this regard is still controversial. C1 NETHERLANDS ENERGY RES FDN, 1755 ZG PETTEN, NETHERLANDS. ARGONNE NATL LAB, ARGONNE, IL 60439 USA. RP BANSIL, A (reprint author), NORTHEASTERN UNIV, DEPT PHYS, BOSTON, MA 02115 USA. NR 16 TC 22 Z9 22 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 3667 EP 3670 DI 10.1103/PhysRevB.43.3667 PN B PG 4 WC Physics, Condensed Matter SC Physics GA FF086 UT WOS:A1991FF08600071 ER PT J AU SHI, DL LING, XS XU, M FANG, MM LUO, S BUDNICK, JI DABROWSKI, B HINKS, DG RICHARDS, DR ZHENG, Y AF SHI, DL LING, XS XU, M FANG, MM LUO, S BUDNICK, JI DABROWSKI, B HINKS, DG RICHARDS, DR ZHENG, Y TI IRREVERSIBILITY IN BA0.625K0.375BIO3 SO PHYSICAL REVIEW B LA English DT Note ID HIGH-TEMPERATURE SUPERCONDUCTORS; BA1-XKXBIO3-Y SYSTEM; FLUX MOTION; CREEP AB An irreversibility line has been identified in bulk Ba0.625K0.375BiO3, which follows the relation 1-T/T(c) approximately H2/3. According to the flux-creep model, the magnetic irreversibility is caused by thermally activated flux creep and is closely connected with the field-induced resistive broadening. However, previous resistivity measurements showed that the Ba0.625K0.375BiO3 system did not exhibit resistive transition broadening. Thus, an alternative explanation based on the Josephson-coupling model is suggested to interpret the irreversibility observed in Ba0.625K0.375BiO3. C1 UNIV CONNECTICUT,DEPT PHYS,STORRS,CT 06269. GEORGIA INST TECHNOL,SCH PHYS,ATLANTA,GA 30332. WESTERN ILLINOIS UNIV,DEPT PHYS,MACOMB,IL 61455. RP SHI, DL (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Ling, Xinsheng/A-9219-2008 NR 16 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 3684 EP 3687 DI 10.1103/PhysRevB.43.3684 PN B PG 4 WC Physics, Condensed Matter SC Physics GA FF086 UT WOS:A1991FF08600076 ER PT J AU VANDERVOORT, KG CRABTREE, GW FANG, Y YANG, S CLAUS, H DOWNEY, JW AF VANDERVOORT, KG CRABTREE, GW FANG, Y YANG, S CLAUS, H DOWNEY, JW TI TIME-DEPENDENT MEISSNER FRACTION AS A FUNCTION OF AGING IN AN OXYGEN-DEFICIENT YBA2CU3O7-DELTA SINGLE-CRYSTAL SO PHYSICAL REVIEW B LA English DT Note AB Meissner- and shielding-effect measurements were made on an oxygen-deficient single crystal of YBa2Cu3O7-delta as a function of aging time at room temperature following a quench from 225-degrees-C. It is seen that the Meissner fraction systematically increases from 11.1% to 13.2% as T(c) changes from 11.2 to 25.0 K. All aging was done within the helium exchange gas environment of the sample chamber. The results point to oxygen vacancy ordering rather than oxygen absorption as the mechanism for both the T(c) and Meissner-fraction increase. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP VANDERVOORT, KG (reprint author), UNIV ILLINOIS,DEPT PHYS,CHICAGO,IL 60680, USA. NR 11 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD FEB 1 PY 1991 VL 43 IS 4 BP 3688 EP 3690 DI 10.1103/PhysRevB.43.3688 PN B PG 3 WC Physics, Condensed Matter SC Physics GA FF086 UT WOS:A1991FF08600077 ER PT J AU DOVER, CB GUTSCHE, T FAESSLER, A AF DOVER, CB GUTSCHE, T FAESSLER, A TI CASE FOR QUASINUCLEAR NBARN BOUND-STATES SO PHYSICAL REVIEW C LA English DT Article ID QUARK REARRANGEMENT MODEL; NUCLEON-ANTINUCLEON RESONANCES; PPBAR ANNIHILATION; PBARP ANNIHILATION; ANTIPROTON ANNIHILATION; NNBAR ANNIHILATION; ANTI-NUCLEONS; S-WAVE; LIQUID DEUTERIUM; POTENTIAL MODEL AB Recent experimental results on nucleon-antinucleon annihilation reactions of the type NBARN-->pi-X have provided evidence for a new mesonic state X2 with quantum numbers J-pi-C(I(G)) = 2++(0+) which lies outside of the usual quark-antiquark (QQBAR) tensor meson nonet of flavor SU(3). We show that the observed production rates of X2 from atomic pBARp states of orbital angular momentum L = 0,1 as well as the decay characteristics of X2, namely, its preference for rho-rho over pi-pi decay and the absence of an observable KBARK mode, are consistent with an interpretation of X2 as a quasinuclear bound state of the NBARN potential. The principal binding mechanism for such states is provided by the coherent tensor forces for isospin I = 0 which arise from meson exchanges. We review the evidence for the 0++(0+) and 1--(0-) states predicted in this model and apply the P3(0) strong-coupling quark model to estimate the decay branching ratios for a variety of NBARN bound states. Key experimental tests of our interpretation are discussed. C1 UNIV TUBINGEN,INST THEORET PHYS,W-7400 TUBINGEN 1,GERMANY. RP DOVER, CB (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 105 TC 59 Z9 59 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 FEB PY 1991 VL 43 IS 2 BP 379 EP 393 DI 10.1103/PhysRevC.43.379 PG 15 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100004 ER PT J AU SCHIAVILLA, R RISKA, DO AF SCHIAVILLA, R RISKA, DO TI THRESHOLD ELECTRODISINTEGRATION AND ELECTROMAGNETIC FORM-FACTORS OF THE DEUTERON SO PHYSICAL REVIEW C LA English DT Article ID HIGH MOMENTUM-TRANSFER; MESON EXCHANGE CURRENTS; E-D SCATTERING; ELASTIC-SCATTERING; MAGNETIC-STRUCTURE; Q2; COINCIDENCE AB The threshold electrodisintegration cross section and electromagnetic form factors of the deuteron are calculated by using the Argonne upsilon-14 model for the nucleon-nucleon interaction to generate the bound-and scattering-state wave functions. The exchange-current operator is constructed to be consistent with the interaction model. The calculated electrodisintegration cross section is in good qualitative agreement with the experimental data over the whole measured momentum-transfer range, and is sensitive to the electromagnetic form factors of the nucleon. The calculated form factors appear to be in good agreement with the empirical values, although uncertainties in the isoscalar model-dependent exchange-current contributions and nucleon electromagnetic form factors prevent definite predictions to be made at high values of momentum transfer. Finally, the cross section for radiative capture of thermal neutrons on protons is found to be within less than 1% of the measured value. C1 UNIV HELSINKI,DEPT PHYS,SF-00170 HELSINKI 17,FINLAND. RP SCHIAVILLA, R (reprint author), ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439, USA. NR 59 TC 77 Z9 77 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 FEB PY 1991 VL 43 IS 2 BP 437 EP 451 DI 10.1103/PhysRevC.43.437 PG 15 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100008 ER PT J AU KORTELAHTI, MO ZGANJAR, EF WOOD, JL BINGHAM, CR CARTER, HK TOTH, KS HAMILTON, JH KORMICKI, J CHATURVEDI, L NEWBOLT, WB AF KORTELAHTI, MO ZGANJAR, EF WOOD, JL BINGHAM, CR CARTER, HK TOTH, KS HAMILTON, JH KORMICKI, J CHATURVEDI, L NEWBOLT, WB TI SHAPE COEXISTENCE IN HG-190 SO PHYSICAL REVIEW C LA English DT Article ID HIGH-SPIN STATES; SHELL-MODEL; EVEN EVEN; ISOTOPES; NUCLEI; BANDS; DECAY; ISOMERISM AB Levels in 190Hg were studied by radioactive decay of isotopically separated 190Tl. A new band was observed with spin parity (energy, keV) of 0+(1279), 2+(1571), 4+(1975), and 6+(2510). Electric monopole transitions were observed between this band and the ground-state band. Relative B(E2) values for intraband transitions in the new band were found to be approximately 200 times those for interband transitions. Systematics of shape coexistence in the light Hg isotopes and their possible relevance to recent observations of superdeformation in these nuclei are discussed. C1 LOUISIANA STATE UNIV,DEPT PHYS & ASTRON,BATON ROUGE,LA 70803. GEORGIA INST TECHNOL,SCH PHYS,ATLANTA,GA 30332. UNIV TENNESSEE,DEPT PHYS & ASTRON,KNOXVILLE,TN 37996. OAK RIDGE ASSOCIATED UNIV,UNISOR,OAK RIDGE,TN 37831. OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831. VANDERBILT UNIV,DEPT PHYS & ASTRON,NASHVILLE,TN 37235. WASHINGTON & LEE UNIV,DEPT PHYS,LEXINGTON,VA 24450. NR 30 TC 18 Z9 18 U1 0 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 484 EP 488 DI 10.1103/PhysRevC.43.484 PG 5 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100013 ER PT J AU WINTERS, RR CARLTON, RF JOHNSON, CH HILL, NW LACERNA, MR AF WINTERS, RR CARLTON, RF JOHNSON, CH HILL, NW LACERNA, MR TI TOTAL CROSS-SECTION AND NEUTRON RESONANCE SPECTROSCOPY FOR N + AR-40 SO PHYSICAL REVIEW C LA English DT Article ID DISPERSIVE OPTICAL-MODEL; MEAN FIELD AB The neutron total cross section for Ar-40 has been measured over the incident neutron energy range 0.007-50 MeV. R-matrix analysis of the cross section from 0.007 to 1.52 MeV provides resonance parameters which provide a complete description of the neutron scattering functions for the s1/2, p1/2, and p3/2 scattering channels and less nearly complete scattering functions for the d3/2 and d5/2 channels. The back-shifted Fermi-gas model is used to model the level densities for s-, p-, and d-wave resonances. C1 MIDDLE TENNESSEE STATE UNIV,MURFREESBORG,TN 37132. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. OHIO STATE UNIV,COLUMBUS,OH 43210. RP WINTERS, RR (reprint author), DENISON UNIV,GRANVILLE,OH 43023, USA. NR 33 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 492 EP 509 DI 10.1103/PhysRevC.43.492 PG 18 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100015 ER PT J AU RAMAN, S WALKIEWICZ, TA KAHANE, S JURNEY, ET SA, J GACSI, Z WEIL, JL ALLAART, K BONSIGNORI, G SHRINER, JF AF RAMAN, S WALKIEWICZ, TA KAHANE, S JURNEY, ET SA, J GACSI, Z WEIL, JL ALLAART, K BONSIGNORI, G SHRINER, JF TI NEARLY COMPLETE LEVEL SCHEME OF SN-116 BELOW 4.3 MEV SO PHYSICAL REVIEW C LA English DT Article ID EVEN SN NUCLEI; COLLECTIVE STATES; SPACING DISTRIBUTIONS; E2-TRANSITION RATES; QUANTUM SPECTRA; ENERGY-LEVELS; TIN ISOTOPES; STATISTICS; DECAY; MODEL AB The level scheme of Sn-116 has been studied by combining the results of Sn-115(n,gamma)Sn-116 and Sn-116(n,n'gamma)Sn-116 experiments. Both experiments were performed using isotopically enriched samples and Ge gamma-ray detectors. Based on the thresholds of gamma-ray excitation functions measured for the Sn-116(n,n'gamma) reaction and the precise gamma-ray energies from the capture reaction, 100 levels were observed below 4.3 MeV excitation energy. Approximately half of these were not known previously. Forty-eight of these levels have unique or tentative spin-parity assignments, and for ten more the spin has been restricted to a single value. The spin-parity for most other levels below 4.3 MeV excitation has been restricted to a few values. These spin-parity assignments and limitations were derived mainly from (n,n'gamma) angular distribution measurements, together with additional information obtained from the cross section magnitudes in both experiments. Above 4.3 MeV excitation energy, 55 additional levels are proposed, based only on the Sn-115(n,gamma) results. No J-pi information is available for these higher-lying levels beyond the fact that they most probably all have J less-than-or-equal-to 4. The level scheme below 4.3 MeV from the current work, together with known high-spin levels up to 5.4 MeV seen in other experiments, are compared to the combined predictions of the two-broken-pair model, the interacting boson model, and the deformed collective model. In addition, several states have been phenomenologically identified as proton 1p-lh and collective quadrupole-octupole two-phonon excitations. It is concluded from the good agreement between experiment and these models that all levels in Sn-116 with J less-than-or-equal-to 6 up to an excitation of 4.0 MeV and J less-than-or-equal-to 3 up to 4.3 MeV may have been experimentally identified. The nearest-neighbor spacing distribution is intermediate between that of a Gaussian orthogonal ensemble and that of a Poisson distribution, with a slight preference for the former. The neutron separation energy was determined to be 9563.47 +/- 0.11 KeV. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. UNIV KENTUCKY,LEXINGTON,KY 40506. FREE UNIV AMSTERDAM,FAC PHYS & ASTRON,1007 MC AMSTERDAM,NETHERLANDS. UNIV BOLOGNA,IST NAZL FIS NUCL,DIPARTIMENTO FIS,I-40126 BOLOGNA,ITALY. TENNESSEE TECHNOL UNIV,COOKEVILLE,TN 38505. RP RAMAN, S (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 89 TC 66 Z9 66 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 FEB PY 1991 VL 43 IS 2 BP 521 EP 555 DI 10.1103/PhysRevC.43.521 PG 35 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100018 ER PT J AU RAMAN, S NESTOR, CW KAHANE, S BHATT, KH AF RAMAN, S NESTOR, CW KAHANE, S BHATT, KH TI LOW-LYING COLLECTIVE QUADRUPOLE AND OCTUPOLE STRENGTHS IN EVEN-EVEN NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID DYNAMICAL SYMMETRY MODEL; SHELL-MODEL; MOMENTS; VALUES; SATURATION; NUCLIDES; ENERGIES; SCHEME; ER-168; TABLE AB The B(E2) up values for the first 2+ state of even-even nuclei in the Z greater-than-or-equal-to 50 region are compared with the predictions of several theoretical models. Comparative estimates of the overall agreement with the data are provided. Gaps and discrepancies in the data and examples that show interesting features such as shape changes are discussed. The B(E2) up values are examined critically to search for the dynamical Pauli effects predicted by the fermion dynamic symmetry model. The empirical B(E2) up and B(E3) up systematics are employed to obtain a measure of the harmonicity of the quadrupole and octupole vibrations. The fraction of the energy-weighted sum-rule strength exhausted by the sum of all known low-lying 2+ states below 2.3 MeV is found to be surprisingly constant in the 60 < A < 250 region except near closed shells. C1 JOINT INST HEAVY ION RES,HOLIFIELD HEAVY ION RES FACIL,OAK RIDGE,TN 37831. UNIV MISSISSIPPI,DEPT PHYS & ASTRON,UNIVERSITY,MS 38677. RP RAMAN, S (reprint author), OAK RIDGE NATL LAB,OAK RIDGE,TN 37831, USA. NR 37 TC 51 Z9 51 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 FEB PY 1991 VL 43 IS 2 BP 556 EP 581 DI 10.1103/PhysRevC.43.556 PG 26 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100019 ER PT J AU WARBURTON, EK BROWN, BA AF WARBURTON, EK BROWN, BA TI APPRAISAL OF THE KUO-HERLING SHELL-MODEL INTERACTION AND APPLICATION TO A=210-212 NUCLEI SO PHYSICAL REVIEW C LA English DT Article ID SPECTROSCOPY; CONFIGURATIONS; SPECTRA; RN-212 AB Shell-model calculations are described for A = 204-212 nuclei. These calculations use the Kuo-Herling realistic effective interactions for hole states and particle states relative to Pb-208. These interactions contain a bare part and a core polarization contribution. The contribution of the core-polarization was varied to find the best fit to the energy spectra of A = 204-206 and 210-212 nuclei. This and other modifications to the Kuo-Herling interaction-designed to give better agreement with experimental energy spectra-are discussed. Aspects of the spectroscopy of Pb-211-112, Po-210, Ra-212, Bi-210, and At-212 are presented in order to illustrate the use of the Kuo-Herling particle interaction. Deficiencies in the Kuo-Herling interaction are described and the desirability and possibility of an improved calculation of the interaction is emphasized. C1 MICHIGAN STATE UNIV,CYCLOTRON LAB,E LANSING,MI 48824. MICHIGAN STATE UNIV,DEPT PHYS & ASTRON,E LANSING,MI 48824. RP WARBURTON, EK (reprint author), BROOKHAVEN NATL LAB,UPTON,NY 11973, USA. NR 34 TC 69 Z9 69 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 FEB PY 1991 VL 43 IS 2 BP 602 EP 617 DI 10.1103/PhysRevC.43.602 PG 16 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100022 ER PT J AU CHBIHI, A SOBOTKA, LG MAJKA, Z SARANTITES, DG STRACENER, DW ABENANTE, V SEMKOW, TM NICOLIS, NG HENSLEY, DC BEENE, JR HALBERT, ML AF CHBIHI, A SOBOTKA, LG MAJKA, Z SARANTITES, DG STRACENER, DW ABENANTE, V SEMKOW, TM NICOLIS, NG HENSLEY, DC BEENE, JR HALBERT, ML TI YIELD DECOMPOSITION AND EXCITATION-ENERGY RECONSTRUCTION IN AN INCOMPLETE FUSION REACTION SO PHYSICAL REVIEW C LA English DT Article ID COMPLEX FRAGMENT EMISSION; LINEAR MOMENTUM-TRANSFER; NEUTRON EMISSION; HOT NUCLEI; COLLISIONS; MODEL; PARTICLES; SYSTEM; DECAY AB The velocity distribution of fusionlike products formed in the reaction 701 MeV Si-28 + Mo-100 is decomposed into 26 incomplete fusion channels. If Coulomb corrections are neglected the yields of the incomplete fusion channels correlate much better with the Q value for projectile fragmentation than with the Q value for incomplete fusion. However, the correlation is much improved for imcomplete fusion if a Coulomb correction is included. The partition of linear momentum between various sources is deduced using the measured residue velocity, multicomponent fits to light charged particle spectra, and mean neutron multiplicities. This reconstruction indicates that a substantial fraction of the momentum is not detected by our apparatus when slow residues are produced. With reasonable assumptions about this missing momentum component, the initial excitation of the compoundlike system is calculated as a function of the residue velocity. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37830. RP CHBIHI, A (reprint author), WASHINGTON UNIV,DEPT CHEM,ST LOUIS,MO 63130, USA. NR 25 TC 26 Z9 26 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 652 EP 665 DI 10.1103/PhysRevC.43.652 PG 14 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100026 ER PT J AU CHBIHI, A SOBOTKA, LG NICOLIS, NG SARANTITES, DG STRACENER, DW MAJKA, Z HENSLEY, DC BEENE, JR HALBERT, ML AF CHBIHI, A SOBOTKA, LG NICOLIS, NG SARANTITES, DG STRACENER, DW MAJKA, Z HENSLEY, DC BEENE, JR HALBERT, ML TI DETERMINATION OF THE NUCLEAR-LEVEL DENSITY AT HIGH-EXCITATION ENERGY SO PHYSICAL REVIEW C LA English DT Article ID TE-117 COMPOUND NUCLEI; EFFECTIVE MASS; HOT NUCLEI; TEMPERATURES; PARAMETER AB Evaporation simulations are presented to illustrate the problems associated with the determination of the nuclear level density constant at high excitation energy from evaporation spectra. The methods of using either the total (whole chain) spectra or the difference (from two different initial excitation energies) spectra are discussed. Data from the study of the reaction 701 MeV Si-28 + Mo-100 are presented and both methods are used to extract the level density constant. We find that in order to reproduce the slopes of the light particle spectra the level density constant must have a value near 1/10A - 1/11A for excited nuclei with statistical temperatures in the range of 3.5 to 5.5 MeV. This presumes that the only parameter adjustment required to treat the decay of highly exited nuclei is the level density constant. If this is so, the shapes of the evaporation spectra imply a reduction in the level density constant from the value required to explain the decay of less highly excited nuclei, a conclusion reached by others. However, the reduced level density constant leads to an overproduction of deuterons and tritons. This suggests that a more complicated set of parameter adjustments may be required to treat the decay of highly excited nuclei. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37830. RP CHBIHI, A (reprint author), WASHINGTON UNIV,DEPT CHEM,ST LOUIS,MO 63130, USA. NR 28 TC 43 Z9 43 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 FEB PY 1991 VL 43 IS 2 BP 666 EP 677 DI 10.1103/PhysRevC.43.666 PG 12 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100027 ER PT J AU DIGREGORIO, DE CHAN, Y CHAVEZ, E DACAL, A ORTIZ, ME SURO, J STOKSTAD, RG AF DIGREGORIO, DE CHAN, Y CHAVEZ, E DACAL, A ORTIZ, ME SURO, J STOKSTAD, RG TI FUSION CROSS-SECTIONS FOR C-12+TE-128 AND THE DEDUCTION OF ABSOLUTE AVERAGE ANGULAR MOMENTA SO PHYSICAL REVIEW C LA English DT Article ID HEAVY-ION REACTIONS; NUCLEI AB Fusion cross sections have been measured for C-12 + Te-128 from E(c.m.) = 40.4 to 56.6 MeV by direct detection and identification of evaporation residues using a time-of-flight technique. Average angular momenta for fusion are deduced from a sharp cutoff approximation at energies above the Coulomb barrier. These values of [l] and those already obtained from isomer ratio measurements are in very good agreement in the energy region where both methods should be valid. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. NR 11 TC 4 Z9 4 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 687 EP 690 DI 10.1103/PhysRevC.43.687 PG 4 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100029 ER PT J AU POULIOT, J CHAN, Y DIGREGORIO, DE HARMON, BA KNOP, R MOISAN, C ROY, R STOKSTAD, RG AF POULIOT, J CHAN, Y DIGREGORIO, DE HARMON, BA KNOP, R MOISAN, C ROY, R STOKSTAD, RG TI EXCITATION AND MULTIPLE DISSOCIATION OF C-12, N-14, AND O-16 PROJECTILES IN PERIPHERAL COLLISIONS AT 32.5 MEV NUCLEON SO PHYSICAL REVIEW C LA English DT Article ID PHOSWICH DETECTOR; FERMI ENERGY; AU-197; FRAGMENTATION; MEV/NUCLEON; PARTICLES; BREAKUP; NE-20; ARRAY; DECAY AB Cross sections for the multiple breakup of O-16, N-14, and C-12 projectiles scattered by an Au target were measured with an array of 34 phoswich detectors. The dissociation of the projectiles into as many as five charged particles has been observed. The yields of different exit channels correlate approximately with the threshold energy for separation of the projectile into the observed fragments. The excitation spectrum of the primary projectile-like nucleus was reconstructed from the measured positions and kinetic energies of the individual fragments. The energy sharing between projectile and target is consistent with a fast excitation mechanism in which differential increases in projectile excitation energy appear to be accompanied by comparable increases in target excitation. Calculations of the yields based on a sequence of binary decays are presented. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720. RP POULIOT, J (reprint author), UNIV LAVAL,PHYS NUCL LAB,QUEBEC CITY G1K 7P4,QUEBEC,CANADA. NR 33 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 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 735 EP 744 DI 10.1103/PhysRevC.43.735 PG 10 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100034 ER PT J AU WILLIAMS, AL MCGILL, JA MORRIS, CL BURLESON, GR FAUCETT, JA OAKLEY, DS BURLEIN, M FORTUNE, HT ODONNELL, JM KAHRIMANIS, GP MOORE, CF AF WILLIAMS, AL MCGILL, JA MORRIS, CL BURLESON, GR FAUCETT, JA OAKLEY, DS BURLEIN, M FORTUNE, HT ODONNELL, JM KAHRIMANIS, GP MOORE, CF TI PION DOUBLE CHARGE-EXCHANGE ON CA-42,44,48 FOR 300-LESS-THAN-OR-EQUAL-TO-T-PI-LESS-THAN-OR-EQUAL-TO-550 MEV SO PHYSICAL REVIEW C LA English DT Article ID ISOBARIC-ANALOG-STATE; NUCLEAR SHELL-MODEL; DELTA-(1232) RESONANCE AB Measurements of cross sections for pion-induced double-charge-exchange reactions to the double-isobaric-analog state for Ca-42,44,48Ca at incident pion energies of 300-550 MeV at theta-lab = 5-degrees are reported together with upper limits for cross sections for transitions to the residual ground states for Ca-44,48Ca. The data are fitted with a two-amplitude model which gives expressions for cross sections for both transitions. The fit overpredicts the ground-state cross sections, indicating a failure of the model in this energy range. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NEW MEXICO STATE UNIV,LAS CRUCES,NM 88003. UNIV COLORADO,BOULDER,CO 80309. UNIV PENN,PHILADELPHIA,PA 19104. RP WILLIAMS, AL (reprint author), UNIV TEXAS,AUSTIN,TX 78712, USA. NR 11 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 FEB PY 1991 VL 43 IS 2 BP 766 EP 770 DI 10.1103/PhysRevC.43.766 PG 5 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100037 ER PT J AU MISHRA, VK HAMA, S CLARK, BC KOZACK, RE MERCER, RL RAY, L AF MISHRA, VK HAMA, S CLARK, BC KOZACK, RE MERCER, RL RAY, L TI IMPLICATIONS OF VARIOUS SPIN-ONE RELATIVISTIC WAVE-EQUATIONS FOR INTERMEDIATE-ENERGY DEUTERON-NUCLEUS SCATTERING SO PHYSICAL REVIEW C LA English DT Article ID GLOBAL OPTICAL POTENTIALS; ELASTIC-SCATTERING; DIRAC-EQUATION; FIELDS; MODEL; CA-40 AB Various relativistic treatments are applied to deuteron-nucleus elastic scattering at intermediate energies. There are various possibilities for spin-one wave equations. Here we have considered three of them, the Kemmer-Duffin-Petiau, Proca, and Weinberg equations. Second-order equations are obtained from each using a similar set of approximations. Elastic-scattering observables including the differential cross section, and the vector and tensor analyzing powers are calculated using all three equations. The different predictions are compared with each other and with experimental data for 400 MeV Ni-58(d,d)Ni-58 and 700 MeV Ca-40(d,d)Ca-40. We find that within the approximations made and for the assumed interactions there are no significant differences between the three sets of predicted observables. C1 OHIO STATE UNIV,DEPT PHYS,COLUMBUS,OH 43210. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. IBM CORP,THOMAS J WATSON RES CTR,YORKTOWN HTS,NY 10598. UNIV TEXAS,DEPT PHYS,AUSTIN,TX 78712. NR 48 TC 35 Z9 35 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 FEB PY 1991 VL 43 IS 2 BP 801 EP 811 DI 10.1103/PhysRevC.43.801 PG 11 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100041 ER PT J AU SZYMANSKI, JJ BARNES, PD DIEBOLD, GE EISENSTEIN, RA FRANKLIN, GB GRACE, R HERTZOG, DW MAHER, CJ QUINN, BP RIEDER, R SEYDOUX, J WHARTON, WR BART, S CHRIEN, RE PILE, P SUTTER, R XU, Y HACKENBURG, R HUNGERFORD, EV KISHIMOTO, T TANG, LG BASSALLECK, B STEARNS, RL AF SZYMANSKI, JJ BARNES, PD DIEBOLD, GE EISENSTEIN, RA FRANKLIN, GB GRACE, R HERTZOG, DW MAHER, CJ QUINN, BP RIEDER, R SEYDOUX, J WHARTON, WR BART, S CHRIEN, RE PILE, P SUTTER, R XU, Y HACKENBURG, R HUNGERFORD, EV KISHIMOTO, T TANG, LG BASSALLECK, B STEARNS, RL TI NONLEPTONIC WEAK DECAY OF HE-5-LAMBDA AND C-12-LAMBDA SO PHYSICAL REVIEW C LA English DT Article ID NON-LEPTONIC DECAYS; LAMBDA-HYPERNUCLEI; B-11-LAMBDA HYPERNUCLEI; ANTIPROTON ANNIHILATION; DELAYED FISSION; 6-QUARK MODEL; MESONIC DECAY; HYPER-NUCLEI; C-12-LAMBDA; STATES AB Hypernuclear lifetime and partial decay-rate measurements made at the Brookhaven National Laboratory Alternating Gradient Synchrotron are reported for He-5-LAMBDA and C-12-LAMBDA. The mesonic and non-mesonic decays are compared to existing weak-interaction calculations. In particular, the non-mesonic reaction LAMBDA-N-->NN is discussed as an example of a nonleptonic weak process for which calculations have been reported using various effective weak Hamiltonians. C1 CARNEGIE MELLON UNIV,DEPT PHYS,PITTSBURGH,PA 15213. BROOKHAVEN NATL LAB,UPTON,NY 11973. UNIV HOUSTON,HOUSTON,TX 77004. UNIV NEW MEXICO,ALBUQUERQUE,NM 87131. VASSAR COLL,POUGHKEEPSIE,NY 12601. RI Franklin, Gregg/N-7743-2014; Quinn, Brian/N-7343-2014 OI Franklin, Gregg/0000-0003-4176-1378; Quinn, Brian/0000-0003-2800-986X NR 58 TC 216 Z9 218 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 FEB PY 1991 VL 43 IS 2 BP 849 EP 862 DI 10.1103/PhysRevC.43.849 PG 14 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100046 ER PT J AU KURATH, D AF KURATH, D TI MEAN-FIELD DESCRIPTION OF LI-11 SO PHYSICAL REVIEW C LA English DT Note AB Recent experiments with radioactive Li-11 beams suggest a neutron halo for this nucleus. The Nilsson model is used to exhibit the underlying reason for this occurrence. RP KURATH, D (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. NR 1 TC 2 Z9 2 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD FEB PY 1991 VL 43 IS 2 BP 911 EP 911 DI 10.1103/PhysRevC.43.911 PG 1 WC Physics, Nuclear SC Physics GA EX561 UT WOS:A1991EX56100054 ER PT J AU ABE, F AMIDEI, D APOLLINARI, G ATAC, M AUCHINCLOSS, P BADEN, AR BAMBERGER, A BARBAROGALTIERI, A BARNES, VE BEDESCHI, F BEHRENDS, S BELFORTE, S BELLETTINI, G BELLINGER, J BENSINGER, J BERETVAS, A BERGE, JP BERTOLUCCI, S BHADRA, S BINKLEY, M BLAIR, R BLOCKER, C BOOTH, AW BRANDENBURG, G BROWN, D BUCKLEY, E BYON, A BYRUM, KL CAMPAGNARI, C CAMPBELL, M CAREY, R CARITHERS, W CARLSMITH, D CARROLL, JT CASHMORE, R CERVELLI, F CHADWICK, K CHIARELLI, G CHINOWSKY, W CIHANGIR, S CLARK, AG CONNOR, D CONTRERAS, M COOPER, J CORDELLI, M CRANE, D CURATOLO, M DAY, C DELLAGNELLO, S DELLORSO, M DEMORTIER, L DERWENT, PF DEVLIN, T DIBITONTO, D DRUCKER, RB ELIAS, JE ELY, R ERREDE, S ESPOSITO, B FLAUGHER, B FOSTER, GW FRANKLIN, M FREEMAN, J FRISCH, H FUKUI, Y FUNAYAMA, Y GARFINKEL, AF GAUTHIER, A GEER, S GIANNETTI, P GIOKARIS, N GIROMINI, P GLADNEY, L GOLD, M GOULIANOS, K GRASSMANN, H GROSSOPILCHER, C HABER, C HAHN, SR HANDLER, R HARA, K HARRIS, RM HAUSER, J HESSING, T HOLLEBEEK, R HOLLOWAY, L HU, P HUBBARD, B HUFFMAN, BT HUGHES, R HURST, P HUTH, J INCAGLI, M INO, T ISO, H JENSEN, H JESSOP, CP JOHNSON, RP JOSHI, U KADEL, RW KAMON, T KANDA, S KARDELIS, DA KARLINER, I KEARNS, E KIM, S KEPHART, R KESTEN, P KEUP, RM KEUTELIAN, H KIRSCH, L KONDO, K KUHLMANN, SE KUNS, E LAASANEN, AT LAMOUREUX, JI LI, W LISS, TM LOCKYER, N LUCHINI, CB MAAS, P MANGANO, M MARRINER, JP MARKELOFF, R MCINTYRE, P MENZIONE, A MEYER, T MARKOSKY, LA MATTINGLY, R MIKAMO, S MILLER, M MIMASHI, T MISCETTI, S MISHINA, M MIYASHITA, S MORITA, Y MOULDING, S MUKHERJEE, A MURAKI, Y NAKAE, L NAKANO, I NELSON, C NEWMANHOLMES, C NG, JST NINOMIYA, M NODULMAN, L OGAWA, S PAOLETTI, R PARA, A PARE, E PATRICK, J PHILLIPS, TJ PLUNKETT, R PONDROM, L PROUDFOOT, J PUNZI, G QUARRIE, D RAGAN, K REDLINGER, G RHOADES, J RIMONDI, F RISTORI, L ROHALY, T ROODMAN, A SANSONI, A SARD, RD SAVOYNAVARRO, A SCARPINE, V SCHLABACH, P SCHMIDT, EE SCHUB, MH SCHWITTERS, R SCRIBANO, A SEGLER, S SEIYA, Y SEKIGUCHI, M SESTINI, P SHAPIRO, M SHEAFF, M SHOCHET, M SIEGRIST, J SINERVO, P SKARHA, J SLIWA, K SMITH, DA SNIDER, FD STDENIS, R STEFANINI, A SWARTZ, RL TAKANO, M TAKIKAWA, K TAREM, S THERIOT, D TIMKO, M TIPTON, P TKACZYK, S TOLLESTRUP, A TONELLI, G TONNISON, J TRISCHUK, W TSAY, Y UKEGAWA, F UNDERWOOD, D VIDAL, R WAGNER, RG WAGNER, RL WALSH, J WATTS, T WEBB, R WENDT, C WESTER, WC WESTHUSING, T WHITE, S WICKLUND, A WILLIAMS, HH WINER, B YAGIL, A YAMASHITA, A YASUOKA, K YEH, GP YOH, J YOKOYAMA, M YUN, JC ZETTI, F AF ABE, F AMIDEI, D APOLLINARI, G ATAC, M AUCHINCLOSS, P BADEN, AR BAMBERGER, A BARBAROGALTIERI, A BARNES, VE BEDESCHI, F BEHRENDS, S BELFORTE, S BELLETTINI, G BELLINGER, J BENSINGER, J BERETVAS, A BERGE, JP BERTOLUCCI, S BHADRA, S BINKLEY, M BLAIR, R BLOCKER, C BOOTH, AW BRANDENBURG, G BROWN, D BUCKLEY, E BYON, A BYRUM, KL CAMPAGNARI, C CAMPBELL, M CAREY, R CARITHERS, W CARLSMITH, D CARROLL, JT CASHMORE, R CERVELLI, F CHADWICK, K CHIARELLI, G CHINOWSKY, W CIHANGIR, S CLARK, AG CONNOR, D CONTRERAS, M COOPER, J CORDELLI, M CRANE, D CURATOLO, M DAY, C DELLAGNELLO, S DELLORSO, M DEMORTIER, L DERWENT, PF DEVLIN, T DIBITONTO, D DRUCKER, RB ELIAS, JE ELY, R ERREDE, S ESPOSITO, B FLAUGHER, B FOSTER, GW FRANKLIN, M FREEMAN, J FRISCH, H FUKUI, Y FUNAYAMA, Y GARFINKEL, AF GAUTHIER, A GEER, S GIANNETTI, P GIOKARIS, N GIROMINI, P GLADNEY, L GOLD, M GOULIANOS, K GRASSMANN, H GROSSOPILCHER, C HABER, C HAHN, SR HANDLER, R HARA, K HARRIS, RM HAUSER, J HESSING, T HOLLEBEEK, R HOLLOWAY, L HU, P HUBBARD, B HUFFMAN, BT HUGHES, R HURST, P HUTH, J INCAGLI, M INO, T ISO, H JENSEN, H JESSOP, CP JOHNSON, RP JOSHI, U KADEL, RW KAMON, T KANDA, S KARDELIS, DA KARLINER, I KEARNS, E KIM, S KEPHART, R KESTEN, P KEUP, RM KEUTELIAN, H KIRSCH, L KONDO, K KUHLMANN, SE KUNS, E LAASANEN, AT LAMOUREUX, JI LI, W LISS, TM LOCKYER, N LUCHINI, CB MAAS, P MANGANO, M MARRINER, JP MARKELOFF, R MCINTYRE, P MENZIONE, A MEYER, T MARKOSKY, LA MATTINGLY, R MIKAMO, S MILLER, M MIMASHI, T MISCETTI, S MISHINA, M MIYASHITA, S MORITA, Y MOULDING, S MUKHERJEE, A MURAKI, Y NAKAE, L NAKANO, I NELSON, C NEWMANHOLMES, C NG, JST NINOMIYA, M NODULMAN, L OGAWA, S PAOLETTI, R PARA, A PARE, E PATRICK, J PHILLIPS, TJ PLUNKETT, R PONDROM, L PROUDFOOT, J PUNZI, G QUARRIE, D RAGAN, K REDLINGER, G RHOADES, J RIMONDI, F RISTORI, L ROHALY, T ROODMAN, A SANSONI, A SARD, RD SAVOYNAVARRO, A SCARPINE, V SCHLABACH, P SCHMIDT, EE SCHUB, MH SCHWITTERS, R SCRIBANO, A SEGLER, S SEIYA, Y SEKIGUCHI, M SESTINI, P SHAPIRO, M SHEAFF, M SHOCHET, M SIEGRIST, J SINERVO, P SKARHA, J SLIWA, K SMITH, DA SNIDER, FD STDENIS, R STEFANINI, A SWARTZ, RL TAKANO, M TAKIKAWA, K TAREM, S THERIOT, D TIMKO, M TIPTON, P TKACZYK, S TOLLESTRUP, A TONELLI, G TONNISON, J TRISCHUK, W TSAY, Y UKEGAWA, F UNDERWOOD, D VIDAL, R WAGNER, RG WAGNER, RL WALSH, J WATTS, T WEBB, R WENDT, C WESTER, WC WESTHUSING, T WHITE, S WICKLUND, A WILLIAMS, HH WINER, B YAGIL, A YAMASHITA, A YASUOKA, K YEH, GP YOH, J YOKOYAMA, M YUN, JC ZETTI, F TI TOP-QUARK SEARCH IN THE ELECTRON+JETS CHANNEL IN PROTON-ANTIPROTON COLLISIONS AT SQUARE-ROOT-S-=1.8 TEV SO PHYSICAL REVIEW D LA English DT Article ID NEUTRAL-CURRENT; HADRONIC COLLISIONS AB A search for the top quark in pBARp collisions at a center-of-mass energy of 1.8 TeV using the Collider Detector at Fermilab is described. A study of events selected by requiring an energetic electron, missing transverse energy, and two or more jets excludes at 95% confidence level the standard-model production and decay of ttBAR pairs if the top-quark mass is between 40 and 77 GeV/c2. The observed electron + multijet data are consistent with W-boson production. C1 BRANDEIS UNIV,WALTHAM,MA 02254. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV CHICAGO,CHICAGO,IL 60637. HARVARD UNIV,CAMBRIDGE,MA 02138. UNIV ILLINOIS,URBANA,IL 61801. PURDUE UNIV,W LAFAYETTE,IN 47907. ROCKEFELLER UNIV,NEW YORK,NY 10021. RUTGERS STATE UNIV,PISCATAWAY,NJ 08854. IST NAZL FIS NUCL,LAB NAZL FRASCATI,FRASCATI,ITALY. NATL LAB HIGH ENERGY PHYS,OHO,IBARAKI 305,JAPAN. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV PENN,PHILADELPHIA,PA 19104. UNIV PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. SCUOLA NORMALE SUPER PISA,I-56100 PISA,ITALY. TEXAS A&M UNIV SYST,COLLEGE STN,TX 77843. UNIV TSUKUBA,SAKURA,IBARAKI 305,JAPAN. TUFTS UNIV,MEDFORD,MA 02155. UNIV WISCONSIN,MADISON,WI 53706. RP ABE, F (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI St.Denis, Richard/C-8997-2012; Chiarelli, Giorgio/E-8953-2012; Punzi, Giovanni/J-4947-2012 OI Chiarelli, Giorgio/0000-0001-9851-4816; Punzi, Giovanni/0000-0002-8346-9052 NR 33 TC 47 Z9 47 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 FEB 1 PY 1991 VL 43 IS 3 BP 664 EP 686 DI 10.1103/PhysRevD.43.664 PG 23 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EU584 UT WOS:A1991EU58400005 ER PT J AU KUEBEL, D PUNDURS, M YUAN, CP BERGER, EL PAIGE, FE AF KUEBEL, D PUNDURS, M YUAN, CP BERGER, EL PAIGE, FE TI COMPARISON OF BOTTOM-QUARK PRODUCTION-RATES IN ISAJET WITH A FULL QCD 2-]3 CALCULATION SO PHYSICAL REVIEW D LA English DT Article ID HEAVY-QUARK; CROSS-SECTION; HADRONIC COLLISIONS; COLLIDER; PARTON AB High-statistics samples of events have been generated with the ISAJET Monte Carlo simulation program in a study of bottom-quark production in proton-antiproton collisions at unroofed radical sign sBAR = 630 and 1800 GeV. These samples include lowest-order QCD production, flavor excitation, and gluon splitting contributions. Both Eichten-Hinchliffe-Lane-Quigg and Diemoz-Ferroni-Longo-Martinelli structure functions have been used. The integral transverse-momentum distribution sigma-T(P(T,b) > P(T,min)) is presented for each data set. Results are compared to a full analytical next-to-leading-order calculation of Nason, Dawson, and Ellis. We find that ISAJET cross sections at large P(T) are greater than the results obtained in the analytical calculation. In addition, the ratio of the full cross section to the lowest-order result (K factor) can be as large as a factor of 2 greater than the analytical result, depending on unroofed radical sign sBAR and P(T). We discuss the implications of these overestimates that relate to the phenomenology of heavy-flavor production, notably searches for the top quark. C1 BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973. RP KUEBEL, D (reprint author), ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439, USA. NR 17 TC 6 Z9 6 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 FEB 1 PY 1991 VL 43 IS 3 BP 767 EP 778 DI 10.1103/PhysRevD.43.767 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EU584 UT WOS:A1991EU58400014 ER PT J AU LADINSKY, GA YUAN, CP AF LADINSKY, GA YUAN, CP TI W-BOSON-TOP-QUARK BACKGROUND TO HEAVY-HIGGS-BOSON PRODUCTION SO PHYSICAL REVIEW D LA English DT Article AB Relevant to WW physics and heavy-Higgs-boson detection through its decay H --> W+ W- --> lv+2 jets at the Superconducting Super Collider is the subprocess bg --> Wt. We study this process over the invariant-mass region M(Wt) > 850 with respect to a 1-TeV Higgs boson using top-quark masses of m(t) = 100 and 175 GeV. The cross sections in this region give a signal-to-background ratio of about 1:20. After applying further restrictions at the hadronic level for eliminating top quarks in conjunction with some basic parton level cuts, we find this ratio can be improved to 1:1. Polarization properties are also discussed. C1 ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. RP LADINSKY, GA (reprint author), IIT,DEPT PHYS,CHICAGO,IL 60615, USA. NR 13 TC 19 Z9 19 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 1 PY 1991 VL 43 IS 3 BP 789 EP 793 DI 10.1103/PhysRevD.43.789 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EU584 UT WOS:A1991EU58400016 ER PT J AU STEPHENSON, GJ MALTMAN, K GOLDMAN, T AF STEPHENSON, GJ MALTMAN, K GOLDMAN, T TI QCD-CORRECTIONS TO QED AND ISOSPIN BREAKING IN THE BARYON SPECTRUM AND VECTOR-MESON MIXING SO PHYSICAL REVIEW D LA English DT Article ID VIOLATING MASS-DIFFERENCES; NUCLEAR-CHARGE ASYMMETRY; RELATIVIZED QUARK-MODEL; HYPERFINE INTERACTIONS; CHROMODYNAMICS; ANGLES; DECAYS AB We reexamine baryon isomultiplet mass splittings and rho-omega mixing including, in addition to the usual one-photon-exchange terms and the light-quark mass difference DELTA-m ( = m(d) - m(u), effective charge-symmetry-breaking operators due to the interference of QED and QCD. We find that these interference terms play a significant role in determining the isomultiplet splittings and that including them in the analysis reduces the extracted value of DELTA-m. C1 UNIV TORONTO,DEPT PHYS,TORONTO M5S 1A7,ONTARIO,CANADA. UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545. RP STEPHENSON, GJ (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545, USA. NR 30 TC 23 Z9 23 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 1 PY 1991 VL 43 IS 3 BP 860 EP 868 DI 10.1103/PhysRevD.43.860 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EU584 UT WOS:A1991EU58400024 ER PT J AU ANJOS, JC APPEL, JA BEAN, A BRACKER, SB BROWDER, TE CREMALDI, LM DUBOSCQ, JE ELLIOT, JR ESCOBAR, CO GIBNEY, MC HARTNER, GF KARCHIN, PE KUMAR, BR LOSTY, MJ LUSTE, GJ MANTSCH, PM MARTIN, JF MCHUGH, S MENARY, SR MORRISON, RJ NASH, T ONG, P PINFOLD, J PUNKAR, G PUROHIT, MV SANTORO, AFS SHOUP, AL SLIWA, K SOKOLOFF, MD SOUZA, MHG SPALDING, WJ STREETMAN, ME STUNDZIA, AB WITHERELL, MS AF ANJOS, JC APPEL, JA BEAN, A BRACKER, SB BROWDER, TE CREMALDI, LM DUBOSCQ, JE ELLIOT, JR ESCOBAR, CO GIBNEY, MC HARTNER, GF KARCHIN, PE KUMAR, BR LOSTY, MJ LUSTE, GJ MANTSCH, PM MARTIN, JF MCHUGH, S MENARY, SR MORRISON, RJ NASH, T ONG, P PINFOLD, J PUNKAR, G PUROHIT, MV SANTORO, AFS SHOUP, AL SLIWA, K SOKOLOFF, MD SOUZA, MHG SPALDING, WJ STREETMAN, ME STUNDZIA, AB WITHERELL, MS TI SOME CABIBBO-SUPPRESSED DECAYS OF THE D0 MESON SO PHYSICAL REVIEW D LA English DT Note ID D+/ DECAYS; DIAGRAM; DS+/ AB Using data from the Fermilab photoproduction experiment E691, we have measured branching ratios for the Cabibbo-suppressed decays D0 --> KBAR0K+ pi-, D0 --> K0K- pi+, D0 --> K-K+ pi-pi+, and D0 --> pi+ pi+ pi- pi-. The data show evidence for several quasi-two-body decays including D0 --> K*+K- and D0 --> KBAR*0K*0, but not D0 --> K*-K+. The relative rates of the charged decays indicates that final-state mesons containing virtual-W+ -decay quarks are more likely to emerge as vector mesons than are those containing the spectator quarks. The high rate observed for D0 --> KBAR*0K*0 indicates that hadronic final-state interactions play a measurable role in charm decays. C1 CARLETON UNIV,OTTAWA K1S 5B6,ONTARIO,CANADA. UNIV CINCINNATI,CINCINNATI,OH 45221. UNIV COLORADO,BOULDER,CO 80309. CTR BRASILEIRO PESQUISAS FIS,BR-22290 RIO DE JANEIRO,BRAZIL. UNIV SAO PAULO,BR-01498 SAO PAULO,BRAZIL. UNIV TORONTO,TORONTO M5S 1A7,ONTARIO,CANADA. YALE UNIV,NEW HAVEN,CT 06511. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV MISSISSIPPI,UNIVERSITY,MS 38677. NATL RES COUNCIL CANADA,OTTAWA K1A 0R6,ONTARIO,CANADA. PRINCETON UNIV,PRINCETON,NJ 08544. RP ANJOS, JC (reprint author), UNIV CALIF SANTA BARBARA,SANTA BARBARA,CA 93106, USA. RI Anjos, Joao/C-8335-2013 NR 22 TC 8 Z9 8 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD FEB 1 PY 1991 VL 43 IS 3 BP R635 EP R640 DI 10.1103/PhysRevD.43.R635 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EU584 UT WOS:A1991EU58400001 ER PT J AU ROMANELLI, F CHEN, L AF ROMANELLI, F CHEN, L TI THE EFFECT OF THE ION TRANSIT RESONANCE ON THE RESISTIVE MAGNETOHYDRODYNAMIC MODES SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID AXISYMMETRIC TOROIDAL PLASMA; BALLOONING MODES; TOKAMAK; INSTABILITIES; STABILITY AB The stability of resistive interchange and ballooning modes is analyzed taking into account the kinetic effects associated with the ion transit resonance. In the parallel compressible limit, it is found that kinetic effects yield an unstable localized mode driven by inverse ion Landau damping. In addition, no threshold is found for the resistive ballooning mode even in the presence of average good curvature, with the effect of the ion transit resonance being destabilizing. C1 PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543. RP ROMANELLI, F (reprint author), CTR RIC ENERGIA FRASCATI,EUROPEAN NUCL ENERGY AGCY,ASSOCIAZ EURATOM,I-00044 FRASCATI,ITALY. OI Romanelli, Francesco/0000-0001-9778-1090 NR 15 TC 10 Z9 10 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD FEB PY 1991 VL 3 IS 2 BP 329 EP 335 DI 10.1063/1.859742 PG 7 WC Physics, Fluids & Plasmas SC Physics GA EV784 UT WOS:A1991EV78400008 ER PT J AU GREENE, GJ GOULD, RW AF GREENE, GJ GOULD, RW TI OBSERVATION OF WAVE-POCKET PROPAGATION IN THE ION-CYCLOTRON RANGE OF FREQUENCIES IN A TOKAMAK PLASMA SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article AB Experimental observation of wave-packet propagation in the ion cyclotron range of frequencies in a tokamak plasma is reported. Studies were carried out in the Caltech Research Tokamak [Phys. Fluids 23, 614 (1980)] in a pure hydrogen plasma and in a regime where fast-wave damping was sufficiently small to permit multiple toroidal transits of the wave packet. Waves were launched by exciting a small loop antenna with a short burst of radio-frequency current and were detected with shielded magnetic probes. Probe scans revealed a large increase in wave-packet amplitude at smaller minor radii, and the packet velocity was found to be independent of radial position. Measurement of the packet transit time yielded direct information about the wave group velocity. Packet velocity was investigated as a function of the fundamental excitation frequency, plasma density, and toroidal magnetic field. Results are compared with the predictions of a cold plasma model that includes a vacuum layer at the edge. C1 CALTECH,PASADENA,CA 91125. RP GREENE, GJ (reprint author), PRINCETON UNIV,PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 23 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 0899-8221 J9 PHYS FLUIDS B-PLASMA PD FEB PY 1991 VL 3 IS 2 BP 406 EP 413 DI 10.1063/1.859750 PG 8 WC Physics, Fluids & Plasmas SC Physics GA EV784 UT WOS:A1991EV78400017 ER PT J AU SIDIKMAN, KL CALLEN, JD NEBEL, RA AF SIDIKMAN, KL CALLEN, JD NEBEL, RA TI EFFECT OF A GRADIENT IN PARALLEL CURRENT ON FIELD ERROR PROFILES IN A REVERSED-FIELD PINCH SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID SIMULATIONS AB Magnetic perturbations caused by external field errors are an important consideration in both the current operation and future design of reversed-field pinch (RFP) devices. Recently, it has been shown that perturbation profiles calculated in the presence of a relaxed RFP equilibrium (J0 = lambda-B0, lambda = const) are amplified when compared to those calculated in vacuum. This work extends the approach to include a partially relaxed equilibrium [lambda = lambda-(r)], which is experimentally realistic, and the effects of finite resistivity, viscosity, and flow. The finite gradient in lambda produces an amplification of the radial magnetic field perturbation much larger than that predicted for constant lambda. Physically, this is due to the presence of an additional perturbed current associated with the gradient in lambda which alters the curvature of the perturbation. Finite resistivity, viscosity, and flow act to reduce this amplification. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RP SIDIKMAN, KL (reprint author), UNIV WISCONSIN,MADISON,WI 53706, USA. NR 18 TC 1 Z9 1 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD FEB PY 1991 VL 3 IS 2 BP 428 EP 435 DI 10.1063/1.859884 PG 8 WC Physics, Fluids & Plasmas SC Physics GA EV784 UT WOS:A1991EV78400020 ER PT J AU BATHA, SH MEYERHOFER, DD SIMON, A DRAKE, RP AF BATHA, SH MEYERHOFER, DD SIMON, A DRAKE, RP TI RAMAN UP-SCATTERING IN LONG-SCALE-LENGTH, LASER-PRODUCED PLASMAS SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID STIMULATED RAMAN; BRILLOUIN-SCATTERING; ABSOLUTE INSTABILITY; SPECTRA; WAVES; MODEL AB Frequency up-shifted light, produced by the interaction of a 351 nm laser with a plasma large enough to produce efficient down-shifted Raman backscattering, was measured. The plasma was created using low-intensity, 351 nm laser beams striking a 15-mu-m thick CH foil. During the period of interest, the electron temperature was estimated to be 1 keV, the peak density to be 0.15 of the critical density, and the plasma scale length to be 1500-mu-m at one-tenth critical density. The most straightforward explanation of the up-shifted light was found to be scattering from externally enhanced plasma waves. Scattering from a plasma mode created by coupling a large ion wave to a stimulated-Raman-scattering-produced plasma wave is also possible. Collisional damping precludes either scattering from a reflected electron-plasma wave produced by SRS or scattering from a plasma wave resulting from the onset of the Langmuir decay instability. C1 UNIV ROCHESTER,DEPT MECH ENGN,ROCHESTER,NY 14619. UNIV ROCHESTER,LASER ENERGET,ROCHESTER,NY 14619. UNIV CALIF DAVIS,DEPT APPL SCI,DAVIS,CA 95616. RP BATHA, SH (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,PLASMA PHYS RES INST,LIVERMORE,CA 94550, USA. RI Drake, R Paul/I-9218-2012 OI Drake, R Paul/0000-0002-5450-9844 NR 21 TC 11 Z9 11 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD FEB PY 1991 VL 3 IS 2 BP 448 EP 454 DI 10.1063/1.859886 PG 7 WC Physics, Fluids & Plasmas SC Physics GA EV784 UT WOS:A1991EV78400023 ER PT J AU BIRN, J AF BIRN, J TI STRETCHED 3-DIMENSIONAL PLASMA EQUILIBRIA WITH FIELD-ALIGNED FLOW SO PHYSICS OF FLUIDS B-PLASMA PHYSICS LA English DT Article ID SELF-CONSISTENT THEORY; DISTANT MAGNETOTAIL; CONVECTION; TAIL AB A three-dimensional equilibrium theory [J. Geophys. Res. 92, 11 101 (1987)] for stretched plasma configurations, such as the Earth's magnetotail, is extended to include the effects of field-aligned flow. The magnetohydrodynamic (MHD) equations for this case be solved in a general way by reduction to a set of ordinary differential equations and an ordinary integral. The solutions represent lowest-order solutions of an asymptotic expansion of the MHD equations for small electric field and weak time dependence. Simplified equations are presented for two-dimensional equilibria and for incompressible flow. Possible magnetospheric applications include the configuration of the geotail near and beyond the termination of the closed field line region, the steady motion of a plasmoid (a plasma bubble severed from the Earth) through the distant geotail, and configurations at the magnetopause, the interface between the magnetosphere and the shocked solar wind plasma. For illustration, solutions for the steady motion of a two-dimensional plasmoid through the distant magnetotail are presented. RP BIRN, J (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545, USA. NR 16 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0899-8221 J9 PHYS FLUIDS B-PLASMA PD FEB PY 1991 VL 3 IS 2 BP 479 EP 484 DI 10.1063/1.859891 PG 6 WC Physics, Fluids & Plasmas SC Physics GA EV784 UT WOS:A1991EV78400028 ER PT J AU MANGANO, ML PARKE, SJ AF MANGANO, ML PARKE, SJ TI MULTI-PARTON AMPLITUDES IN GAUGE-THEORIES SO PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS LA English DT Review ID LARGE TRANSVERSE-MOMENTUM; E + E(-)->MU+MU(-)GAMMA-GAMMA; QCD RADIATIVE-CORRECTIONS; SOFT GLUON INTERFERENCE; MONTE-CARLO SIMULATION; HIGH-ENERGIES; E+E-ANNIHILATION; HADRON COLLIDERS; CROSS-SECTIONS; SINGLE BREMSSTRAHLUNG AB In this report we review recent developments in perturbation-theory methods for gauge theories. We present techniques and results that are useful in the calculation of cross sections for processes with many final-state partons which have applications in the study of multi-jet phenomena in high-energy colliders. C1 DIPARTIMENTO FIS,PISA,ITALY. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP MANGANO, ML (reprint author), SCUOLA NORMALE SUPER PISA,IST NAZL FIS NUCL,I-56100 PISA,ITALY. NR 117 TC 489 Z9 490 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-1573 J9 PHYS REP JI Phys. Rep.-Rev. Sec. Phys. Lett. PD FEB PY 1991 VL 200 IS 6 BP 301 EP 367 DI 10.1016/0370-1573(91)90091-Y PG 67 WC Physics, Multidisciplinary SC Physics GA FC851 UT WOS:A1991FC85100001 ER PT J AU JOVANOVIC, D AF JOVANOVIC, D TI MYSTERY, NOT HISTORY, DRIVES PARTICLE PHYSICS SO PHYSICS TODAY LA English DT Letter RP JOVANOVIC, D (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, 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 FEB PY 1991 VL 44 IS 2 BP 11 EP 11 PG 1 WC Physics, Multidisciplinary SC Physics GA EX276 UT WOS:A1991EX27600002 ER PT J AU ALLEN, L BUCHSBAUM, SJ GIBBONS, JH HECKER, SS KNAPP, EA YONAS, G LUBKIN, GB GOODWIN, I LEVI, BG AF ALLEN, L BUCHSBAUM, SJ GIBBONS, JH HECKER, SS KNAPP, EA YONAS, G LUBKIN, GB GOODWIN, I LEVI, BG TI ROUND-TABLE - NEW CHALLENGES FOR THE NATIONAL LABS SO PHYSICS TODAY LA English DT Discussion AB America's government laboratories are a reservoir of scientific and technological capabilities. They contribute to national defense, scientific discoveries, space exploration, better agriculture and improved health care. Over the past decade, Congress has directed the labs to pass along their research ideas and technological knowhow to commercial companies in an effort to enhance the country's competitiveness in global markets. In an attempt to understand how the national labs can best achieve their new mission while retaining their old strengths, PHYSICS TODAY editors brought together six prominent members of the nation's R&D enterprise to discuss the issues. C1 AT&T BELL LABS,TECHNOL SYST,MURRAY HILL,NJ 07974. US CONGRESS,OFF TECHNOL ASSESSMENT,WASHINGTON,DC. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87544. NATL SCI FDN,WASHINGTON,DC 20550. SANDIA NATL LABS,LAB DEV,ALBUQUERQUE,NM 87185. RP ALLEN, L (reprint author), CALTECH,JET PROP LAB,PASADENA,CA 91109, 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 FEB PY 1991 VL 44 IS 2 BP 24 EP 35 DI 10.1063/1.881279 PG 12 WC Physics, Multidisciplinary SC Physics GA EX276 UT WOS:A1991EX27600009 ER PT J AU COLE, F LENNOX, A COHEN, L ROSENBERG, I KUCHNIR, F DELUCA, P AF COLE, F LENNOX, A COHEN, L ROSENBERG, I KUCHNIR, F DELUCA, P TI AWSCHALOM,MIGUEL - OBITUARY SO PHYSICS TODAY LA English DT Item About an Individual C1 MICHAEL REESE HOSP & MED CTR,CHICAGO,IL 60616. UNIV CHICAGO,CHICAGO,IL 60637. UNIV WISCONSIN,MADISON,WI 53706. RP COLE, F (reprint author), FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510, 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 FEB PY 1991 VL 44 IS 2 BP 116 EP 117 DI 10.1063/1.2810008 PG 2 WC Physics, Multidisciplinary SC Physics GA EX276 UT WOS:A1991EX27600020 ER PT J AU JANOUDI, AK POFF, KL AF JANOUDI, AK POFF, KL TI CHARACTERIZATION OF ADAPTATION IN PHOTOTROPISM OF ARABIDOPSIS-THALIANA SO PLANT PHYSIOLOGY LA English DT Article ID MAIZE COLEOPTILES; LIGHT; SEEDLINGS; BLUE AB Phototropic curvature has been measured for etiolated Arabidopsis thaliana seedlings with and without a preirradiation. A bilateral preirradiation with 450-nm light at a fluence greater than about 0.1 micromole per square meter causes a rapid desensitization to a subsequent 450-nanometer unilateral irradiation at 0.5 micromole per square meter. Following a refractory period, the capacity to respond phototropically recovers to the predesensitization level, and the response is then enhanced. The length of the refractory period is between 10 and 20 minutes. Both the time needed for recovery and the extent of enhancement increase with increasing fluence of the bilateral preirradiation. Based on the relative spectral sensitivities of desensitization and enhancement, these responses can be separated. Desensitization is induced by blue light but not by red light. Enhancement, however, is induced by both blue and red light. Thus, enhancement can be induced without desensitization but not vice versa. Both desensitization and enhancement affect only the magnitude of the response and do not affect the fluence threshold. C1 MICHIGAN STATE UNIV,US DOE,PLANT RES LAB,E LANSING,MI 48824. FU NIDCR NIH HHS [DE-ACO2-76ERO-1338] NR 11 TC 33 Z9 33 U1 0 U2 1 PU AMER SOC PLANT PHYSIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 SN 0032-0889 J9 PLANT PHYSIOL JI Plant Physiol. PD FEB PY 1991 VL 95 IS 2 BP 517 EP 521 DI 10.1104/pp.95.2.517 PG 5 WC Plant Sciences SC Plant Sciences GA EY884 UT WOS:A1991EY88400028 PM 11537487 ER PT J AU FELDMAN, DL AF FELDMAN, DL TI THE GREAT-PLAINS GARRISON DIVERSION UNIT AND THE SEARCH FOR AN ENVIRONMENTAL ETHIC SO POLICY SCIENCES LA English DT Article AB The Garrison Diversion Unit (GDU) was authorized by Congress in 1965. It is one of the largest and most expensive public works projects ever undertaken in the United States. When completed, it may become the last major federal irrigation scheme constructed in the west. Its principal purposes are: (1) to irrigate some 250,000 acres of arable land in North Dakota, (2) provide water for municipal and industrial use in fourteen communities, and (3) enhance recreational opportunities and fish and wildlife management programs within, and adjacent to, the canals and reservoirs resulting from its construction. The project is to be financed by hydropower sales from Lake Sakakawea, created when Garrison Dam was completed in 1956. Concerted litigation, Canadian opposition, and federal budget cuts have sharply reduced the size and scope of GDU since 1984. Its irrigable acreage has been reduced by over 50%, a principal feeder reservoir has been eliminated, and provision of municipal and industrial water delivery has been moved from second to first priority by a Congressional commission. The GDU controversy illustrates the consequences of the lack of a coherent environmental ethic guiding American natural resources policy. These consequences are two-fold. First, although GDU's impacts extend to Canada, there is little agreement between the U.S. and Canada over what values should guide transboundary water resources development. Second, American beneficiaries of the project define its need in 'pre-emptory' terms - i.e., as compensation to an entire region for losses of land associated with the original construction of Garrison Dam. Opponents, meanwhile, argue their case in 'meliorative' terms - i.e., that the costs to society of building additional water projects are not outweighed by their benefits. While both views have some merit, neither view can alone encompass the range of social, economic, and environmental consequences of complex river basin development. RP FELDMAN, DL (reprint author), OAK RIDGE NATL LAB,DIV ENERGY,OAK RIDGE,TN 37831, USA. NR 43 TC 2 Z9 2 U1 1 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0032-2687 J9 POLICY SCI JI Policy Sci. PD FEB PY 1991 VL 24 IS 1 BP 41 EP 64 DI 10.1007/BF00146464 PG 24 WC Planning & Development; Public Administration; Social Sciences, Interdisciplinary SC Public Administration; Social Sciences - Other Topics GA FC389 UT WOS:A1991FC38900003 ER PT J AU BODNARCZUK, M AF BODNARCZUK, M TI QUARKS, LEPTONS, AND QUALITY ASSURANCE SO QUALITY PROGRESS LA English DT Article RP BODNARCZUK, M (reprint author), FERMI NATL ACCELERATOR LAB,QUAL ASSURANCE COMM,BATAVIA,IL 60510, USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC QUALITY CONTROL-ASQC PI MILWAUKEE PA ASQC MEMBERSHIP MANAGER 611 E. WISCONSIN AVENUE, MILWAUKEE, WI 53202 SN 0033-524X J9 QUAL PROG JI Qual. Prog. PD FEB PY 1991 VL 24 IS 2 BP 83 EP 86 PG 4 WC Engineering, Multidisciplinary; Engineering, Industrial; Management; Operations Research & Management Science SC Engineering; Business & Economics; Operations Research & Management Science GA EX491 UT WOS:A1991EX49100016 ER PT J AU MEECHAN, PJ VAUGHAN, ATM GIOMETTI, CS GRDINA, DJ AF MEECHAN, PJ VAUGHAN, ATM GIOMETTI, CS GRDINA, DJ TI ASSOCIATION OF WR-1065 WITH CHO-AA8 CELLS, NUCLEI, AND NUCLEOIDS SO RADIATION RESEARCH LA English DT Article ID DNA DAMAGE; V79 CELLS; 2-DIMENSIONAL ANALYSIS; TISSUE PROTEINS; WR-2721; WR1065; REPAIR; RADIOPROTECTION; DERIVATIVES; ETHANETHIOL C1 UNIV BIRMINGHAM,SCH MED,DEPT IMMUNOL,BIRMINGHAM B15 2TJ,W MIDLANDS,ENGLAND. ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. RP MEECHAN, PJ (reprint author), NO ILLINOIS UNIV,DEPT BIOL SCI,DE KALB,IL 60115, USA. FU NCI NIH HHS [CA-37435]; NCRR NIH HHS [S07 RR07176] NR 27 TC 9 Z9 9 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 FEB PY 1991 VL 125 IS 2 BP 152 EP 157 DI 10.2307/3577882 PG 6 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA EX538 UT WOS:A1991EX53800005 PM 1996372 ER PT J AU COOKS, RG ROCKWOOD, AL AF COOKS, RG ROCKWOOD, AL TI THE THOMSON - A SUGGESTED UNIT FOR MASS SPECTROSCOPISTS SO RAPID COMMUNICATIONS IN MASS SPECTROMETRY LA English DT Letter ID ELECTROSPRAY IONIZATION C1 PURDUE UNIV, DEPT CHEM, W LAFAYETTE, IN 47907 USA. PACIFIC NW LAB, DEPT CHEM SCI, RICHLAND, WA 99352 USA. RI Cooks, R/G-1051-2015 OI Cooks, R/0000-0002-9581-9603 NR 3 TC 167 Z9 168 U1 0 U2 7 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX, ENGLAND PO19 1UD SN 0951-4198 J9 RAPID COMMUN MASS SP JI Rapid Commun. Mass Spectrom. PD FEB PY 1991 VL 5 IS 2 BP 93 EP 93 PG 1 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA EX906 UT WOS:A1991EX90600010 ER PT J AU ROTURIER, J MILLS, E AF ROTURIER, J MILLS, E TI ENERGY-CONSERVATION AND THE BERKELEY-SCHOOL SO RECHERCHE LA French DT Article C1 UNIV CALIF BERKELEY,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720. UNIV LUND,DEPT ETUD SYST ENERGET ENVIRONM,S-22101 LUND,SWEDEN. RP ROTURIER, J (reprint author), UNIV BORDEAUX 1,F-33405 TALENCE,FRANCE. NR 13 TC 0 Z9 0 U1 0 U2 1 PU SOC ED SCIENTIFIQUES PI PARIS 06 PA 57 RUE DE SEINE, 75280 PARIS 06, FRANCE SN 0029-5671 J9 RECHERCHE JI Recherche PD FEB PY 1991 VL 22 IS 229 BP 256 EP 266 PG 11 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EV338 UT WOS:A1991EV33800017 ER PT J AU MCKONE, TE DANIELS, JI AF MCKONE, TE DANIELS, JI TI ESTIMATING HUMAN EXPOSURE THROUGH MULTIPLE PATHWAYS FROM AIR, WATER, AND SOIL SO REGULATORY TOXICOLOGY AND PHARMACOLOGY LA English DT Article ID VOLATILE ORGANIC-COMPOUNDS; FUGACITY; BIOCONCENTRATION; DEPOSITION; CHEMICALS; INGESTION; RISK RP MCKONE, TE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 29 TC 50 Z9 51 U1 2 U2 13 PU ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 SN 0273-2300 J9 REGUL TOXICOL PHARM JI Regul. Toxicol. Pharmacol. PD FEB PY 1991 VL 13 IS 1 BP 36 EP 61 DI 10.1016/0273-2300(91)90040-3 PG 26 WC Medicine, Legal; Pharmacology & Pharmacy; Toxicology SC Legal Medicine; Pharmacology & Pharmacy; Toxicology GA EX212 UT WOS:A1991EX21200004 PM 2024045 ER PT J AU GRISHAM, LR FALTER, H CAUSEY, R CHRISMAN, W STEVENSON, T WRIGHT, K AF GRISHAM, LR FALTER, H CAUSEY, R CHRISMAN, W STEVENSON, T WRIGHT, K TI EXPERIMENTS WITH HIGH-VOLTAGE INSULATORS IN THE PRESENCE OF TRITIUM SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SURFACE FLASHOVER AB During the final deuterium-tritium phases of the TFTR and JET tokamaks half of the neutral injectors will be used to produce tritium neutral beams to maintain an equal mix of deuterium and tritium in the core plasma, and such requirements may also occur in future devices. This will require that the voltage hold off capabilities of the high voltage insulators in the accelerators be unimpaired by any charge buildups associated with the beta decay of adsorbed layers. We report tests in which we measured the drain currents under high dc voltage of TFTR and JET accelerator insulators while they were successively exposed to vacuum, deuterium and tritium. There did not appear to be any substantial reduction in hold-off capability with tritium, although at some voltages there was a small increase in the leakage current. We also compared the breakdown properties of a plastic tubing filled with deuterium and then tritium at varying pressures, since such tubing has been considered as a high-voltage break in the gas feed system for TFTR, and the presence of large numbers of electron-ion pairs might lead to enhanced Paschen breakdown. We found no significant differences in the behavior for the geometry used. C1 JOINT EUROPEAN TORUS,ABINGDON,ENGLAND. SANDIA NATL LABS,LIVERMORE,CA 94550. RP GRISHAM, LR (reprint author), PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08543, USA. NR 5 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 FEB PY 1991 VL 62 IS 2 BP 376 EP 380 DI 10.1063/1.1142131 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EW414 UT WOS:A1991EW41400015 ER PT J AU ESTLER, RC NOGAR, NS MUENCHAUSEN, RE WU, XD FOLTYN, S GARCIA, AR AF ESTLER, RC NOGAR, NS MUENCHAUSEN, RE WU, XD FOLTYN, S GARCIA, AR TI A VERSATILE SUBSTRATE HEATER FOR USE IN HIGHLY OXIDIZING ATMOSPHERES SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID MOLECULAR-BEAM EPITAXY; THIN-FILMS; GROWTH AB We report the design, construction and performance of a versatile substrate heater that meets the severe design constraints of heating substrates to high temperatures (less-than-or-equal-to 900-degrees-C) in relatively high pressures (hundreds of Torr) of oxidizing gases. The heater has been used to heat substrates by both thermal conduction via a conductive high temperature cement and by direct radiation. In particular, the production of high-quality YBa2Cu3O7-delta thin films grown on radiatively heated LaAlO3 substrates is demonstrated using the pulsed laser deposition (PLD) technique. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR EXPLORATORY RES & DEV,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545. FT LEWIS COLL,DEPT CHEM,DURANGO,CO 81301. RP ESTLER, RC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR EXPLORATORY RES & DEV,DIV CHEM & LASER SCI,LOS ALAMOS,NM 87545, USA. NR 12 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 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD FEB PY 1991 VL 62 IS 2 BP 437 EP 440 DI 10.1063/1.1142139 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EW414 UT WOS:A1991EW41400023 ER PT J AU FARTASH, A SCHULLER, IK GRIMSDITCH, M AF FARTASH, A SCHULLER, IK GRIMSDITCH, M TI VIBRATING MEMBRANE ELASTOMETER FOR RELIABLE MEASUREMENT OF MECHANICAL-PROPERTIES OF METALLIC-FILMS SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID INTERNAL-FRICTION; ELASTIC-MODULUS; APPARATUS; FOILS AB We describe an apparatus for measuring the biaxial mechanical properties of metallic films. A circular knife-edge support forms a drum-head geometry over which the film to be studied is stretched. The film's tension is obtained from the frequency of its membrane modes, and its strain by using an optical technique. The biaxial modulus is obtained from the ratio of tension and strain. An electronic detection system is developed that regeneratively locks to the film's resonant frequency. The system is also capable of measuring the film's damping when the lock is switched off. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP FARTASH, A (reprint author), UNIV CALIF SAN DIEGO,DEPT PHYS,B-019,LA JOLLA,CA 92093, USA. NR 22 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 FEB PY 1991 VL 62 IS 2 BP 494 EP 501 DI 10.1063/1.1142093 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA EW414 UT WOS:A1991EW41400032 ER PT J AU MANGOLD, DC TSANG, CF AF MANGOLD, DC TSANG, CF TI A SUMMARY OF SUBSURFACE HYDROLOGICAL AND HYDROCHEMICAL MODELS SO REVIEWS OF GEOPHYSICS LA English DT Review ID REACTIVE CHEMICAL-TRANSPORT; FRACTURED POROUS-MEDIA; ION-EXCHANGING SOLUTES; GROUNDWATER-FLOW; EQUILIBRIUM CHEMISTRY; CONTAMINANT MIGRATION; MINERAL SOLUBILITIES; NUMERICAL-SIMULATION; IMMISCIBLE FLUIDS; UNSATURATED ZONE AB Numerical simulation in space and time is an established method in fluid flow and solute transport studies. Similarly, the modeling of equilibrium chemistry of aqueous systems has been well developed. Coupling hydrologic transport models and aqueous chemical models is being actively pursued by a number of research groups. To provide a review for researchers as well as field practitioners who may need to select and use models of varying degrees of complexity, summaries of 56 major numerical codes are made in comparative tables with selected references for three broad classes of codes: hydrologic transport models, geochemical models, and hydrochemical models that combine the chemical and transport models. Criteria for code selection and explanations as to how their characteristics were compiled are described. The governing equations for hydrologic flow, solute transport, and chemical relations are briefly described and discussed in light of the assumptions made by the different codes that employ them. Limitations of current modeling conceptualization and practice and areas of present active research effort are noted. Some comments are also given on model validation, a topic of current concern for modeling. Experience in model applications for each code and available information regarding its verification and validation are given in the appendix. RP MANGOLD, DC (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV EARTH SCI,BERKELEY,CA 94720, USA. NR 216 TC 96 Z9 99 U1 4 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD FEB PY 1991 VL 29 IS 1 BP 51 EP 79 DI 10.1029/90RG01715 PG 29 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA EY103 UT WOS:A1991EY10300003 ER PT J AU MURNANE, MM KAPTEYN, HC ROSEN, MD FALCONE, RW AF MURNANE, MM KAPTEYN, HC ROSEN, MD FALCONE, RW TI ULTRAFAST X-RAY PULSES FROM LASER-PRODUCED PLASMAS SO SCIENCE LA English DT Article ID AMPLIFICATION; ABSORPTION; GENERATION; EMISSION; FEMTOSECOND; SPECTROSCOPY; RADIATION; EXPANSION; TARGETS; METAL AB A high-temperature plasma is created when an intense laser pulse is focused onto the surface of a solid. An ultrafast pulse of x-ray radiation is emitted from such a plasma when the laser pulse length is less than a picosecond. A high-speed streak camera detector was used to determine the duration of these x-ray pulses, and computer simulations of the plasmas agree with the experimental results. Sealing laws predict that brighter and more efficient x-ray sources will be obtained by the use of more intense laser pulses. These sources can be used for time-resolved x-ray scattering studies and for the development of x-ray lasers. C1 UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. RI Kapteyn, Henry/H-6559-2011 OI Kapteyn, Henry/0000-0001-8386-6317 NR 61 TC 280 Z9 283 U1 8 U2 29 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 1 PY 1991 VL 251 IS 4993 BP 531 EP 536 DI 10.1126/science.251.4993.531 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EV459 UT WOS:A1991EV45900042 PM 17840864 ER PT J AU NELSON, DE AF NELSON, DE TI A NEW METHOD FOR CARBON ISOTOPIC ANALYSIS OF PROTEIN SO SCIENCE LA English DT Article ID ACCELERATOR MASS-SPECTROMETRY; BONE-COLLAGEN; RADIOCARBON; RATIOS; MARINE; C-13 AB The reaction of ninhydrin with amino acids can be used in carbon isotopic studies of protein. The reaction can be applied to extract as carbon dioxide only peptide-bonded carbon in proteinaceous material, thus avoiding most, if not all, contaminants. Test radiocarbon dates on ancient bone indicate that the method provides reliable ages, and stable carbon isotopic data suggest that our understanding of isotopic dietary reconstruction needs detailed examination. The technique should also be useful in biochemical tracing experiments and in global carbon budget studies, and the underlying principle may be applicable to other isotopes and molecules. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,CTR ACCELERATOR MASS SPECT,LIVERMORE,CA 94550. NR 27 TC 44 Z9 44 U1 1 U2 4 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 1 PY 1991 VL 251 IS 4993 BP 552 EP 554 DI 10.1126/science.1990430 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EV459 UT WOS:A1991EV45900048 PM 1990430 ER PT J AU FELDMAN, GJ STEINBERGER, J AF FELDMAN, GJ STEINBERGER, J TI THE NUMBER OF FAMILIES OF MATTER SO SCIENTIFIC AMERICAN LA English DT Article AB Are the fundamental particles that form matter really fundamental? Researchers at the European laboratory for particle physics (CERN) and at the Stanford Linear Accelerator (SLAC) have found that these particles are the basis for just three "families" of matter. They arrived at the answer by studying the decay of supermassive particles called Z bosons. C1 STANFORD UNIV,STANFORD LINEAR ACCELERATOR CTR,STANFORD,CA 94305. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. CERN,CH-1211 GENEVA 23,SWITZERLAND. RP FELDMAN, GJ (reprint author), HARVARD UNIV,CAMBRIDGE,MA 02138, USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD FEB PY 1991 VL 264 IS 2 BP 70 EP & PG 0 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EU604 UT WOS:A1991EU60400009 ER PT J AU HOWELLS, MR KIRZ, J SAYRE, D AF HOWELLS, MR KIRZ, J SAYRE, D TI X-RAY MICROSCOPES SO SCIENTIFIC AMERICAN LA English DT Article AB Each development in microscopy has revealed a new way to view the world. The optical microscope illuminated single-cell organisms; the electron microscope provided views of minute structures and viruses. Now the X-ray microscope can render three-dimensional images of cells and other specimens in their natural state at 10 times the resolution of optical microscopes. C1 SUNY STONY BROOK,PHYS,STONY BROOK,NY 11794. BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973. NR 6 TC 24 Z9 24 U1 0 U2 3 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 SN 0036-8733 J9 SCI AM JI Sci.Am. PD FEB PY 1991 VL 264 IS 2 BP 88 EP 94 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EU604 UT WOS:A1991EU60400011 PM 2000484 ER PT J AU HAN, SH GSCHNEIDNER, KA BEAUDRY, BJ AF HAN, SH GSCHNEIDNER, KA BEAUDRY, BJ TI PREPARATION OF A METASTABLE HIGH-TEMPERATURE PHASE (GAMMA-DY2S3) AND A METASTABLE HIGH-PRESSURE PHASE (GAMMA-Y2S3) BY MECHANICAL ALLOYING AND MECHANICAL MILLING SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article C1 IOWA STATE UNIV SCI & TECHNOL,DEPT MAT SCI & ENGN,AMES,IA 50011. RP HAN, SH (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 15 TC 25 Z9 26 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD FEB PY 1991 VL 25 IS 2 BP 295 EP 298 DI 10.1016/0956-716X(91)90181-Y PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EV843 UT WOS:A1991EV84300006 ER PT J AU MERK, N TANNER, LE AF MERK, N TANNER, LE TI SOLID-STATE AMORPHIZATION AND CONTAMINATION OF NI-TA POWDERS DURING BALL-MILLING SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID ZR ALLOYS C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV CHEM & MAT SCI,LIVERMORE,CA 94550. RP MERK, N (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,NATL CTR ELECTR MICROSCOPY,BERKELEY,CA 94720, USA. NR 9 TC 4 Z9 4 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD FEB PY 1991 VL 25 IS 2 BP 309 EP 313 DI 10.1016/0956-716X(91)90184-3 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EV843 UT WOS:A1991EV84300009 ER PT J AU WILLIFORD, RE AF WILLIFORD, RE TI FRACTAL FATIGUE SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article ID DIMENSION; SURFACES; PROFILES RP WILLIFORD, RE (reprint author), PACIFIC NW LAB, RICHLAND, WA 99352 USA. NR 26 TC 4 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD FEB PY 1991 VL 25 IS 2 BP 455 EP 460 DI 10.1016/0956-716X(91)90210-R PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EV843 UT WOS:A1991EV84300035 ER PT J AU ADVANI, AH ATTERIDGE, DG MURR, LE BRUEMMER, SM CHELAKARA, R AF ADVANI, AH ATTERIDGE, DG MURR, LE BRUEMMER, SM CHELAKARA, R TI DEFORMATION EFFECTS ON CHROMIUM DIFFUSIVITY AND GRAIN-BOUNDARY CHROMIUM DEPLETION DEVELOPMENT IN TYPE-316 STAINLESS-STEELS SO SCRIPTA METALLURGICA ET MATERIALIA LA English DT Article C1 PACIFIC NW LAB, RICHLAND, WA 99352 USA. OREGON GRAD INST, BEAVERTON, OR 97006 USA. UNIV TEXAS, AUSTIN, TX 78712 USA. UNIV TEXAS, DEPT MET & MAT ENGN, EL PASO, TX 79968 USA. RP ADVANI, AH (reprint author), UNIV TEXAS, INST MFG & MAT MANAGEMENT, EL PASO, TX 79968 USA. OI Murr, Lawrence/0000-0001-5942-8376 NR 9 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0956-716X J9 SCRIPTA METALL MATER JI Scr. Metall. Materialia PD FEB PY 1991 VL 25 IS 2 BP 461 EP 465 DI 10.1016/0956-716X(91)90211-I PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA EV843 UT WOS:A1991EV84300036 ER PT J AU HALLER, EE AF HALLER, EE TI HYDROGEN IN CRYSTALLINE SEMICONDUCTORS SO SEMICONDUCTOR SCIENCE AND TECHNOLOGY LA English DT Review AB The state of the current understanding of hydrogen in elemental and compound semiconductors is reviewed. The results of new experimental and theoretical studies of the microscopic structure of acceptor-hydrogen and donor-hydrogen complexes are presented. Questions regarding hydrogen tunnelling in some of the acceptor and donor complexes in elemental semiconductors, as well as the problem of electronic states of isolated hydrogen, are discussed in the light of the most recent experimental findings. Also, some promising areas of future research are indicated. RP HALLER, EE (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,BERKELEY,CA 94720, USA. NR 0 TC 28 Z9 28 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TECHNO HOUSE, REDCLIFFE WAY, BRISTOL, ENGLAND BS1 6NX SN 0268-1242 J9 SEMICOND SCI TECH JI Semicond. Sci. Technol. PD FEB PY 1991 VL 6 IS 2 BP 73 EP 84 DI 10.1088/0268-1242/6/2/001 PG 12 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA EX863 UT WOS:A1991EX86300001 ER PT J AU LEIMKUHLER, B PETZOLD, LR GEAR, CW AF LEIMKUHLER, B PETZOLD, LR GEAR, CW TI APPROXIMATION METHODS FOR THE CONSISTENT INITIALIZATION OF DIFFERENTIAL-ALGEBRAIC EQUATIONS SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE DIFFERENTIAL-ALGEBRAIC EQUATIONS; CONSISTENT INITIAL VALUES; NUMERICAL METHODS ID SYSTEMS AB The algebraic constraints in a system of differential-algebraic equations (DAEs) impose a consistency requirement on the initial values that can be difficult to satisfy. In this paper the consistency requirement is characterized by a system of equations. An approximation method is introduced for these equations, and the numerical solution of the resulting system is analyzed for certain important classes of DAEs. Finally, a numerical experiment is described. C1 UNIV ILLINOIS,DEPT COMP SCI,URBANA,IL 61801. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV COMP & MATH RES,LIVERMORE,CA 94550. RP LEIMKUHLER, B (reprint author), UNIV KANSAS,DEPT MATH,LAWRENCE,KS 66045, USA. RI Leimkuhler, Benedict/F-8532-2010 NR 19 TC 55 Z9 55 U1 1 U2 3 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER PH#382-9800, PHILADELPHIA, PA 19104-2688 SN 0036-1429 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD FEB PY 1991 VL 28 IS 1 BP 205 EP 226 DI 10.1137/0728011 PG 22 WC Mathematics, Applied SC Mathematics GA EX039 UT WOS:A1991EX03900011 ER PT J AU More, JJ Toraldo, G AF More, Jorge J. Toraldo, Gerardo TI ON THE SOLUTION OF LARGE QUADRATIC PROGRAMMING PROBLEMS WITH BOUND CONSTRAINTS SO SIAM JOURNAL ON OPTIMIZATION LA English DT Article DE quadratic programming; large-scale; conjugate gradients; gradient projection AB An algorithm is proposed that uses the conjugate gradient method to explore the face of the feasible region defined by the current iterate, and the gradient projection method to move to a different face. It is proved that for strictly convex problems the algorithm converges to the solution, and that if the solution is nondegenerate, then the algorithm terminates at the solution in a finite number of steps. Numerical results are presented for the obstacle problem, the elastic-plastic torsion problem, and the journal bearing problems. On a selection of these problems with dimensions ranging from 5000 to 15,000, the algorithm determines the solution in fewer than 15 iterations, and with a small number of function-gradient evaluations and Hessian-vector products per iteration. C1 [More, Jorge J.] Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. [Toraldo, Gerardo] Univ Basilicata, Dipartimento Matemat, I-85100 Potenza, Italy. RP More, JJ (reprint author), Argonne Natl Lab, Div Math & Comp Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. FU Applied Mathematical Sciences subprogram of the Office of Energy Research, U.S. Department of Energy [W-31-109-Eng-38] FX This work was supported by the Applied Mathematical Sciences subprogram of the Office of Energy Research, U.S. Department of Energy, contract W-31-109-Eng-38. NR 27 TC 168 Z9 172 U1 2 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1052-6234 EI 1095-7189 J9 SIAM J OPTIMIZ JI SIAM J. Optim. PD FEB PY 1991 VL 1 IS 1 BP 93 EP 113 DI 10.1137/0801008 PG 21 WC Mathematics, Applied SC Mathematics GA V40SQ UT WOS:000209498700008 ER PT J AU HEEB, E OTT, HR FELDER, E HULLIGER, F SCHILLING, A FISK, Z AF HEEB, E OTT, HR FELDER, E HULLIGER, F SCHILLING, A FISK, Z TI VARIATION OF GROUND-STATES IN CEPT2-XAUXSI2 COMPOUNDS (X = 0, 1, 2) SO SOLID STATE COMMUNICATIONS LA English DT Article ID MAGNETIC-PROPERTIES; RARE-EARTH AB A comparison is made of some low-temperature properties of CePt2Si2, CePtAuSi2 and CeAu2Si2. New experimental data on the specific heat, electrical resistivity and magnetic susceptibility of CePtAuSi2, together with published results on the other compounds, reveal that the electronic ground state in these materials varies in a very significant way. In-between local-moment behaviour in CeAu2Si2 and a Kondo-type ground state in CePt2Si2, CePtAuSi2 forms a heavy-electron state at low temperatures. C1 SWISS FED INST TECHNOL,FESTKORPERPHYS LAB,CH-8093 ZURICH,SWITZERLAND. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 12 TC 3 Z9 3 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND OX5 1GB SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD FEB PY 1991 VL 77 IS 5 BP 323 EP 326 DI 10.1016/0038-1098(91)90742-E PG 4 WC Physics, Condensed Matter SC Physics GA EV379 UT WOS:A1991EV37900002 ER PT J AU TAYLOR, TN MUENCHAUSEN, RE HOFFBAUER, MA AF TAYLOR, TN MUENCHAUSEN, RE HOFFBAUER, MA TI THE STRUCTURE AND MORPHOLOGY OF AG FILM GROWTH ON CU(110) SO SURFACE SCIENCE LA English DT Article ID SURFACE SEGREGATION; ADSORPTION; AU; OVERLAYERS; LEED; RECONSTRUCTION; NUCLEATION; TRANSITION; STABILITY; SI(111) AB Low-energy electron diffraction (LEED), Auger electron spectrometry (AES), and workfunction change measurements have been used to characterize the structure and morphology of ultrathin Ag films grown on Cu(110). The LEED data show pronounced differences in diffraction arrays for multilayer deposition at 120 and greater-than-or-equal-to 300 K that are, respectively, consistent with disordered layering and layer-cluster growth morphologies deduced from AES. Following the initial growth of Ag in-registry with the substrate troughs, a split c(2 x 4) monolayer structure is observed that to first order is interpreted in terms of a distorted Ag(111) overlayer with a seventh-order superlattice periodicity normal to the substrate troughs. At 120 K, postmonolayer deposition reconstructs the monolayer template, prodicing a p(8 x 1) --> p(8 x 3) --> p(8/7 x 3) sequence of diffraction features. These data are consistent with development of a heavily corrugated and strained Ag(110) film that grows from a configuration where the first atomic layer of Ag is captured in the Cu troughs. Multilayer coverages at greater-than-or-equal-to 300 K give LEED features that are indicative of clusters, which gradually coalesce to produce {111} microfacets in a geometry that is consistent with the 120 K structural observations. In agreement with trends seen in bulk binary properties of Ag and Cu, the film development appears to be driven by dominant Ag-Ag bonding as modulated by the row-trough substrate corrugation. The clustering is viewed as the most energetically favorable way to relieve the interfacial strain and attain a bulk Ag film in the absence of low-temperature kinetic limitations. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR EXPLORATORY RES & DEV,LOS ALAMOS,NM 87545. RP TAYLOR, TN (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV CHEM & LASER SCI,LOS ALAMOS,NM 87545, USA. NR 32 TC 14 Z9 14 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB PY 1991 VL 243 IS 1-3 BP 65 EP 82 DI 10.1016/0039-6028(91)90346-T PG 18 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FD225 UT WOS:A1991FD22500018 ER PT J AU ERSCHBAUMER, H FREEMAN, AJ FU, CL PODLOUCKY, R AF ERSCHBAUMER, H FREEMAN, AJ FU, CL PODLOUCKY, R TI SURFACE-STATES, ELECTRONIC-STRUCTURE AND SURFACE-ENERGY OF THE AG(001) SURFACE SO SURFACE SCIENCE LA English DT Article ID IMAGE-POTENTIAL STATES; PLANE-WAVE METHOD; INVERSE PHOTOEMISSION; AG(100); ELECTROREFLECTANCE; SPECTROSCOPY; METALS; BAND AB Surface states, electronic structure and surface energy of a clean Ag(001) surface are determined using the local density full potential linearized augmented plane wave calculations for an 11 layer slab. C1 OAK RIDGE NATL LAB,DIV MET & CERAM,OAK RIDGE,TN 37831. UNIV VIENNA,INST PHYS CHEM,A-1010 VIENNA,AUSTRIA. RP ERSCHBAUMER, H (reprint author), NORTHWESTERN UNIV,DEPT PHYS & ASTRON,EVANSTON,IL 60208, USA. NR 30 TC 39 Z9 39 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB PY 1991 VL 243 IS 1-3 BP 317 EP 322 DI 10.1016/0039-6028(91)90369-4 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FD225 UT WOS:A1991FD22500041 ER PT J AU SINNIAH, K SANDS, WD HRBEK, J YATES, JT JANDA, KC AF SINNIAH, K SANDS, WD HRBEK, J YATES, JT JANDA, KC TI ISOTOPE MIXING BETWEEN CHEMISORBED CO MOLECULES ON A K-PROMOTED NI(111) SURFACE - AN LITD STUDY SO SURFACE SCIENCE LA English DT Letter ID METASTABLE QUENCHING SPECTROSCOPY; THERMAL-DESORPTION; POTASSIUM AB The laser induced thermal desorption technique (LITD) is used to monitor the extent of isotope mixing between CO molecules on a potassium promoted, (theta-K = 0.28) Ni(111) surface. The onset of isotope mixing is found to occur at 400 K, well below the CO or potassium thermal desorption temperature. The maximum mixing yield is about 60% of the statistical limit over the temperature range of 450 to 600 K, suggesting that not all CO on the surface participates in the isotopic mixing reaction due to limited mobility. It is shown that the LITD technique can be used to measure the rate of mixing at temperatures well below that at which thermal desorption occurs. At 475 K the observed isotope exchange rate is consistent with a second order rate constant of k = 6 x 10(-2) ML-1 S-1. C1 UNIV PITTSBURGH,CTR SURFACE SCI,PITTSBURGH,PA 15260. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. RP SINNIAH, K (reprint author), UNIV PITTSBURGH,DEPT CHEM,PITTSBURGH,PA 15260, USA. RI Hrbek, Jan/I-1020-2013 NR 9 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB PY 1991 VL 243 IS 1-3 BP L67 EP L69 PG 3 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FD225 UT WOS:A1991FD22500008 ER PT J AU SOMORJAI, GA AF SOMORJAI, GA TI THE PUZZLES OF SURFACE SCIENCE AND RECENT ATTEMPTS TO EXPLAIN THEM SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 26TH CONF OF THE YAMADA SCIENCE FOUNDATION : SURFACE AS A NEW MATERIAL CY JUL 02-06, 1990 CL OSAKA, JAPAN SP YAMADA SCI FDN ID TRANSITION-METAL SURFACES; RH(111) CRYSTAL-SURFACE; ETHYLENE ADSORPTION; CARBON-MONOXIDE; BENZENE; INTENSITIES; KINETICS AB Surfaces have several unique properties that remain unexplained at the atomic level. These include: (1) the unique chemical activity of rough surfaces; (2) the breaking of chemical bonds in narrow temperature ranges: and (3) the role of co-adsorption and strongly adsorbed monolayers during catalysis and tribological change (friction, lubrication). The dynamic surface restructuring model and surface structure induced variations in local density of states that have been suggested to rationalize the surface behavior await experimental confirmation. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,BERKELEY,CA 94720. RP SOMORJAI, GA (reprint author), UNIV CALIF BERKELEY,DEPT CHEM,BERKELEY,CA 94720, USA. NR 30 TC 44 Z9 44 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB PY 1991 VL 242 IS 1-3 BP 481 EP 488 DI 10.1016/0039-6028(91)90313-H PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA FA165 UT WOS:A1991FA16500083 ER PT J AU KAVLOCK, RJ GREENE, JA KIMMEL, GL MORRISSEY, RE OWENS, E ROGERS, JM SADLER, TW STACK, HF WATERS, MD WELSCH, F AF KAVLOCK, RJ GREENE, JA KIMMEL, GL MORRISSEY, RE OWENS, E ROGERS, JM SADLER, TW STACK, HF WATERS, MD WELSCH, F TI ACTIVITY PROFILES OF DEVELOPMENTAL TOXICITY - DESIGN CONSIDERATIONS AND PILOT IMPLEMENTATION SO TERATOLOGY LA English DT Article ID ETHYLENETHIOUREA-INDUCED HYDROCEPHALUS; METABOLIC-ACTIVATION SYSTEM; EMBRYO TERATOGENESIS ASSAY; GENETIC-ACTIVITY PROFILES; INVIVO TERATOLOGY SCREEN; RATS EXPOSED INUTERO; 2 INVITRO ASSAYS; CHICK-EMBRYOS; PREGNANT RATS; FROG EMBRYO AB The available literature was searched for quantitative test results from both in vitro and in vivo assays for developmental toxicity for five model compounds: cyclophosphamide, methotrexate, hydroxyurea, caffeine, and ethylenethiourea. These compounds were chosen on the basis of their extensive utilization in a variety of assay systems for developmental toxicity as evidenced by their representation in the ETIC database (each generally has 100-500 citations encompassing multiple test systems). Nine cellular-based assays, six assays using whole embryos in culture, as well as Segment II and abbreviated exposure tests for mammalian test species are included in the database. For each assay, the critical endpoints were identified, each of which was then provided a three-letter code, and the criteria for extraction of quantitative information were established. The extracted information was placed into a computerized reference file and subsequently plotted such that the qualitative (positive/negative) and quantitative (e.g., IC50, highest ineffective dose (HID), lowest effective dose (LED)) results across all test systems could be displayed. The information contained in these profiles can be used to compare qualitative and quantitative results across multiple assay systems, to identify data gaps in the literature, to evaluate the concordance of the assays, to calculate relative potencies, and to examine structure-activity relationships. C1 BURROUGHS WELLCOME CO,RES TRIANGLE PK,NC 27709. CHEM IND INST TOXICOL,RES TRIANGLE PK,NC 27709. UNIV N CAROLINA,CHAPEL HILL,NC 27514. US EPA,WASHINGTON,DC 20460. ENVIRONM HLTH RES & TESTING INC,CHAPEL HILL,NC. OAK RIDGE NATL LAB,HUMAN GENOME & TOXICOL GRP,OAK RIDGE,TN. MERCK SHARP & DOHME LTD,W POINT,PA 19486. RP KAVLOCK, RJ (reprint author), US EPA,RES TRIANGLE PK,NC 27711, USA. NR 142 TC 6 Z9 6 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 0040-3709 J9 TERATOLOGY JI Teratology PD FEB PY 1991 VL 43 IS 2 BP 159 EP 185 DI 10.1002/tera.1420430208 PG 27 WC Developmental Biology; Toxicology SC Developmental Biology; Toxicology GA EV805 UT WOS:A1991EV80500007 PM 2014481 ER PT J AU VALTAZANOS, P ELBERT, ST XANTHEAS, S RUEDENBERG, K AF VALTAZANOS, P ELBERT, ST XANTHEAS, S RUEDENBERG, K TI THE RING-OPENING OF CYCLOPROPYLIDENE TO ALLENE - GLOBAL FEATURES OF THE REACTION SURFACE SO THEORETICA CHIMICA ACTA LA English DT Article DE CYCLOPROPYLIDENE TO ALLENE; BIFURCATING TRANSITION REGION; STRAINED RINGS; POTENTIAL ENERGY SURFACE; CONTOUR MAPS ID MOLECULAR-ORBITAL METHODS; INTRINSIC REACTION COORDINATE; SLATER-TYPE ORBITALS; SPACE SCF METHOD; ELECTRONIC WAVEFUNCTIONS; GAUSSIAN EXPANSIONS; ROTATIONAL BARRIER; EXPECTATION VALUES; INTERNAL-ROTATION; TRANSITION-STATES AB The global features of the groundstate ring opening of cyclopropylidene to allene are studied by means of ab-initio FORS MCSCF calculations based on a minimal AO basis set. The energy surface is completely mapped out in terms of three reaction coordinates, namely the CCC ring-opening angle and two angles describing the rotations of the CH2 groups. For each choice of these three variables, the twelve remaining internal coordinates are optimized by energy minimization. In the initial phase of the reaction, as the CCC angle opens, the CH2 groups rotate in a disrotatory manner, maintaining C(s) symmetry. This uphill reaction path leads to a transition region which occurs early, for a CCC angle of about 84-degrees. In this transition region the reaction path branches into two pathways which are each others' mirror images. The system exhibits thus a bifuracting transition region. Passed this region, the two pathways are overall conrotatory in character. However, these downhill reaction paths to the products are poorly defined because, from a CCC opening angle of about 90-degrees on, the CH2 groups can rotate freely and isoenergetically in a synchronized, cogwheel-like manner and this disrotatory motion can mix unpredictably with the conrotatory downhill motion. There is no preference for any one of the two reaction pathways yielding the two stereoisomers of allene and the reaction is therefore nonstereospecific with respect to the numbered hydrogen atoms. The global surface is documented by means of contour maps representing slices corresponding to constant CCC angles. The bifurcating transition region is mapped in detail. C1 IOWA STATE UNIV SCI & TECHNOL, DEPT CHEM, AMES, IA 50011 USA. RP VALTAZANOS, P (reprint author), US DOE, AMES, IA 50011 USA. RI Xantheas, Sotiris/L-1239-2015; Elbert, Stephen/F-9019-2016; OI Elbert, Stephen/0000-0003-2258-8901; Xantheas, Sotiris/0000-0002-6303-1037 NR 75 TC 52 Z9 52 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD FEB-MAR PY 1991 VL 78 IS 5-6 BP 287 EP 326 DI 10.1007/BF01112344 PG 40 WC Chemistry, Physical SC Chemistry GA FB736 UT WOS:A1991FB73600001 ER PT J AU XANTHEAS, S VALTAZANOS, P RUEDENBERG, K AF XANTHEAS, S VALTAZANOS, P RUEDENBERG, K TI THE RING-OPENING OF CYCLOPROPYLIDENE TO ALLENE AND THE ISOMERIZATION OF ALLENE - ABINITIO INTERPRETATION OF THE ELECTRONIC REARRANGEMENTS IN TERMS OF QUASI-ATOMIC ORBITALS SO THEORETICA CHIMICA ACTA LA English DT Article DE CYCLOPROPYLIDENE TO ALLENE; ORBITAL INTERPRETATION OF ELECTRONIC REARRANGEMENTS; POTENTIAL ENERGY SURFACE ID WAVEFUNCTIONS AB A full optimized reaction space (FORS) remains invariant under arbitrary orthogonal transformations among its configuration-generating molecular orbitals. Localization of the latter for a FORS wavefunction yields molecular orbitals with quasi-atomic character which can be interpreted as molecule-adapted minimal-basis-set atomic orbitals. In terms of these quasi-atomic FORS MOs, the configuration mixing in the FORS wavefunction, the representation of the density matrix, and the expansions of the natural orbitals provide information about the interactions that are responsible for the molecular energy changes. A basis-set-independent population analysis can be formulated which accomplishes the objectives of Mulliken's population analysis without the drawbacks stemming from the basis-set dependence of the latter. Through application of these procedures, explanations can be found for various features of the potential energy surface governing the ring opening of cyclopropylidene and the isomerization of allene. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. US DOE,AMES,IA 50011. RI Xantheas, Sotiris/L-1239-2015; OI Xantheas, Sotiris/0000-0002-6303-1037 NR 18 TC 28 Z9 28 U1 1 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD FEB-MAR PY 1991 VL 78 IS 5-6 BP 327 EP 363 DI 10.1007/BF01112345 PG 37 WC Chemistry, Physical SC Chemistry GA FB736 UT WOS:A1991FB73600002 ER PT J AU XANTHEAS, S ELBERT, ST RUEDENBERG, K AF XANTHEAS, S ELBERT, ST RUEDENBERG, K TI THE RING-OPENING OF CYCLOPROPYLIDENE TO ALLENE - KEY FEATURES OF THE ACCURATE REACTION SURFACE SO THEORETICA CHIMICA ACTA LA English DT Article DE CYCLOPROPYLIDENE TO ALLENE; POTENTIAL ENERGY SURFACE; EXTENDED BASIS SETS; ENLARGED CONFIGURATION SPACES ID ORBITAL BASES AB The global potential energy surface, determined in the first paper [1] for the groundstate ring opening of cyclopropylidene to allene, is complemented by accurate calculations of its key regions. The basis set is extended and polarization functions are included. The full configuration space of four electrons in four reactive orbitals is enlarged to the full configuration space of eight electrons in eight active orbitals by including correlations in the unbroken, but stretched CC sigma bonds. The effect of further single and double excitations is examined. The geometries and relative energies of the critical regions are found to change only little except for the ring-opening energy barrier which is lowered to about 7 kcal/mol, in good agreement with the experimental estimate of about 6 kcal/mol. Furthermore, the bifurcation is shown to occur after the transition state, in the neighborhood of a conical intersection on the steepest descent path from the ring-opening transition state to the allene isomerization transition state. The steepest descent paths and the conical intersection are documented in detail. The cogwheel-like free internal rotation of the two methyl groups is confirmed by the accurate calculations. A similar richness of features is believed to exist on many potential energy surfaces governing chemical reactions. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. US DOE,AMES,IA 50011. RI Xantheas, Sotiris/L-1239-2015; Elbert, Stephen/F-9019-2016; OI Elbert, Stephen/0000-0003-2258-8901; Xantheas, Sotiris/0000-0002-6303-1037 NR 17 TC 42 Z9 42 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD FEB-MAR PY 1991 VL 78 IS 5-6 BP 365 EP 395 DI 10.1007/BF01112346 PG 31 WC Chemistry, Physical SC Chemistry GA FB736 UT WOS:A1991FB73600003 ER PT J AU VALTAZANOS, P RUEDENBERG, K AF VALTAZANOS, P RUEDENBERG, K TI THE RING-OPENING OF SUBSTITUTED CYCLOPROPYLIDENES TO SUBSTITUTED ALLENES - THE EFFECTS OF STERIC AND LONG-RANGE ELECTROSTATIC INTERACTIONS SO THEORETICA CHIMICA ACTA LA English DT Article DE CYCLOPROPYLIDENE TO ALLENE (SUBSTITUTED); ELECTROSTATIC INTERACTIONS BETWEEN SUBSTITUENTS ID CONFORMATIONAL-ANALYSIS AB It is shown that all stereospecific preferences found experimentally for the ring opening of substituted cyclopropylidenes are satisfactorily reproduced by adding steric and long-range electrostatic interactions to the cyclopropylidene reaction surface. The corresponding surface for dimethyl cyclopropylidene is mapped out in detail. The surface for 3-methyl- and 2-bromo-3-methyl-cyclopropylidene is explored around the transition region. From the success of this approach it is inferred that short-range covalent interactions are unlikely to be responsible for sterospecific preferences found in these systems. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT CHEM,AMES,IA 50011. RP VALTAZANOS, P (reprint author), US DOE,AMES,IA 50011, USA. NR 21 TC 22 Z9 22 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 SN 0040-5744 J9 THEOR CHIM ACTA JI Theor. Chim. Acta PD FEB-MAR PY 1991 VL 78 IS 5-6 BP 397 EP 416 DI 10.1007/BF01112347 PG 20 WC Chemistry, Physical SC Chemistry GA FB736 UT WOS:A1991FB73600004 ER PT J AU MANNINEN, DL EVANS, RW DUGAN, MK RADER, B AF MANNINEN, DL EVANS, RW DUGAN, MK RADER, B TI THE COSTS AND OUTCOME OF KIDNEY-TRANSPLANT GRAFT FAILURE SO TRANSPLANTATION PROCEEDINGS LA English DT Article ID STAGE RENAL-DISEASE; QUALITY; LIFE RP MANNINEN, DL (reprint author), BATTELLE SEATTLE RES CTR,HLTH & POPULAT RES CTR,4000 NE 41ST ST,SEATTLE,WA 98105, USA. NR 18 TC 16 Z9 16 U1 0 U2 0 PU APPLETON & LANGE PI E NORWALK PA 25 VAN ZANT ST, E NORWALK, CT 06855 SN 0041-1345 J9 TRANSPLANT P JI Transplant. Proc. PD FEB PY 1991 VL 23 IS 1 BP 1312 EP 1314 PN 2 PG 3 WC Immunology; Surgery; Transplantation SC Immunology; Surgery; Transplantation GA EV391 UT WOS:A1991EV39100163 PM 1824895 ER PT J AU EVANS, RW MANNINEN, DL DONG, F AF EVANS, RW MANNINEN, DL DONG, F TI THE CENTER EFFECT IN KIDNEY-TRANSPLANTATION SO TRANSPLANTATION PROCEEDINGS LA English DT Article ID MEDICARE-DESIGNATED CENTERS; CARDIAC TRANSPLANTATION; RENAL-TRANSPLANTATION; GRAFT-SURVIVAL; UNITED-KINGDOM; IRELAND RP EVANS, RW (reprint author), BATTELLE SEATTLE RES CTR,HLTH & POPULAT RES CTR,4000 NE 41ST ST,SEATTLE,WA 98105, USA. NR 29 TC 15 Z9 15 U1 0 U2 0 PU APPLETON & LANGE PI E NORWALK PA 25 VAN ZANT ST, E NORWALK, CT 06855 SN 0041-1345 J9 TRANSPLANT P JI Transplant. Proc. PD FEB PY 1991 VL 23 IS 1 BP 1315 EP 1317 PN 2 PG 3 WC Immunology; Surgery; Transplantation SC Immunology; Surgery; Transplantation GA EV391 UT WOS:A1991EV39100164 PM 1989224 ER PT J AU BURR, B BURR, FA AF BURR, B BURR, FA TI RECOMBINANT INBREDS FOR MOLECULAR MAPPING IN MAIZE - THEORETICAL AND PRACTICAL CONSIDERATIONS SO TRENDS IN GENETICS LA English DT Review ID FRAGMENT LENGTH POLYMORPHISMS; LINKAGE MAPS; GENES; SUSCEPTIBILITY; FREQUENCY; HAPLOIDS; STRAINS; BARLEY; LINES; LOCI AB Molecular mapping is rapidly being extended to more species as one result of the current emphasis on genome initiatives. The choice of the population used for mapping can have important consequences on the efficiency and accessibility of the mapping information. Recombinant inbred lines offer certain advantages over other mapping populations for many species. These more or less permanent population permit many geneticists to contribute to the mapping effort and to profit from each other's work. Recombinant inbred lines are used extensively in mouse genetic and have been used in maize to compile a detailed molecular map. RP BURR, B (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. NR 33 TC 194 Z9 205 U1 0 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, OXON, ENGLAND OX5 1GB SN 0168-9525 J9 TRENDS GENET JI Trends Genet. PD FEB PY 1991 VL 7 IS 2 BP 55 EP 60 DI 10.1016/0168-9525(91)90042-O PG 6 WC Genetics & Heredity SC Genetics & Heredity GA ET668 UT WOS:A1991ET66800008 PM 2035192 ER PT J AU TADESSE, W SHUFORD, JW TAYLOR, RW ADRIANO, DC SAJWAN, KS AF TADESSE, W SHUFORD, JW TAYLOR, RW ADRIANO, DC SAJWAN, KS TI COMPARATIVE AVAILABILITY TO WHEAT OF METALS FROM SEWAGE-SLUDGE AND INORGANIC SALTS SO WATER AIR AND SOIL POLLUTION LA English DT Article ID CATION-EXCHANGE CAPACITY; HEAVY-METALS; PLANT UPTAKE; CADMIUM UPTAKE; SOIL; YIELD; PH; INCUBATION; PHOSPHORUS; SOYBEANS AB A greenhouse experiment was conducted to evaluate the availability of metals from sewage sludge and inorganic salts, and the effect of pH and soil type on yield and metal (Zn, Cu, Cd and Ni) uptake by wheat (Triticum aestivum L. var. 'holly'). Soils used in this study were Hartsells sandy loam (fine-loamy, siliceous Thermic Typic Hapludult) and Decatur silty clay loam (Clayey, kaolinitic, Thermic Rhodic Paleudult). Two treatments of sewage sludge containing metals were applied at the rate of 20 and 100 mt ha-1. Inorganic Salts of Zn, Cu, Cd, and Ni were applied (as sulfate salts) at concentrations equivalent to those found in the 20 and 100 mt ha-1 sludge. One treatment consisted of inorganic metals plus sewage at the 20 Mg ha-1 rate. Two soil pH levels, one at field pH (below 6.0) and another pH adjusted between 6.5 and 7.0 were used. Wheat plants were harvested four weeks after germination. Two more subsequent harvests were made at four week intervals. For each harvest, dry matter yield increased as the rate of sludge application increased for both soil types. The soil pH also influenced the dry matter yield. High yield was observed when the pH was adjusted between 6.5 to 7.0 for both soils. An increase in yield was also observed at each subsequent harvest for most of the treatments. Inorganic salt treatments produced lower dry matter yields when compared with the sludge. Both sludge application and metal salts increased plant tissue concentration of Zn, Cu, Cd, and Ni at field pH for both soils. However, increasing the pH of the soil for both sludge and inorganic salt treatments generally decreased the tissue concentration of the above metals. C1 UNIV GEORGIA,DIV BIOGEOCHEM,SAVANNAH RIVER ECOL LAB,PO DRAWER E,AIKEN,SC 29801. ALABAMA A&M UNIV,DEPT PLANT & SOIL SCI,NORMAL,AL 35762. NR 53 TC 15 Z9 15 U1 0 U2 0 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 FEB PY 1991 VL 55 IS 3-4 BP 397 EP 408 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA FZ939 UT WOS:A1991FZ93900010 ER PT J AU CIESLAK, MJ AF CIESLAK, MJ TI THE WELDING AND SOLIDIFICATION METALLURGY OF ALLOY 625 SO WELDING JOURNAL LA English DT Article DE MICROSTRUCTURE DEVELOPMENT; SOLIDIFICATION CRACK; GTA ALLOY 625 WELDS; DIFFERENTIONAL ANALYSIS; THERMAL ANALYSIS; EUTECTIC CONSTITUENT; GAMMA-LAVES CONSTITUENTS; GAMMA-MC CARBIDE; GAMMA-M6 CARBIDE; NB-CONTAINING ALLOYS ID CRACKING AB The weld metal microstructure development and solidification cracking behavior of Alloy 625 gas tungsten arc (GTA) welds as a function of composition has been determined. A three-factor, two-level, factorially-designed set of alloys involving the elements C, Si and Nb was examined. Differential thermal analysis (DTA) of these alloys indicated that Nb, and to a lesser extent C and Si, increased the melting/solidification temperature range. The DTA revealed that terminal solidification constituents were formed in the Nb-bearing alloys, the presence of which was confirmed by optical and electron microscopy techniques and identified as gamma/MC-(NbC) carbide, gamma/Laves and gamma/MgC carbide eutectic-type constituents. Addition of carbon to the Nb-bearing alloys was observed to promote the formation of the gamma/MC(NbC) carbide constituent and Si was observed to promote increased formation of the gamma/Laves constituent. Regression analysis of Varestraint hot-crack testing data revealed that additions of C or Si to Alloy 625 increased the susceptibility of the alloy to hot cracking. Niobium-free alloys were observed to have a very low tendency toward solidification hot cracking, but even among these alloys, C and Si additions were detrimental. It was concluded that the increased solidification temperature range and formation of Nb-rich eutectic constituents were primarily responsible for the increased susceptibility of Nb-bearing alloys to solidification cracking. RP CIESLAK, MJ (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 29 TC 47 Z9 47 U1 1 U2 8 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 SN 0043-2296 J9 WELD J JI Weld. J. PD FEB PY 1991 VL 70 IS 2 BP S49 EP S56 PG 8 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA EV943 UT WOS:A1991EV94300013 ER PT J AU OLBRIGHT, GR BRYAN, RP LEAR, K BRENNAN, TM POIRIER, G LEE, YH JEWELL, JL AF OLBRIGHT, GR BRYAN, RP LEAR, K BRENNAN, TM POIRIER, G LEE, YH JEWELL, JL TI CASCADABLE LASER LOGIC DEVICES - DISCRETE INTEGRATION OF PHOTOTRANSISTORS WITH SURFACE-EMITTING LASER-DIODES SO ELECTRONICS LETTERS LA English DT Article DE LOGIC DEVICES; OPTICAL LOGIC AB A new class of cascadable optical logic devices is described which consists of integrated GaAs/AlGaAs phototransistors and surface-emitting lasers. The devices function as optical neurons ('smart pixels'), have high optical gain (a factor of > 20 overall, > 200 differential), very high on/off contrast (> 2700, 34 dB) and are ideal for neural networks and optical computing applications. C1 AT&T BELL LABS,HOLMDEL,NJ 07733. RP OLBRIGHT, GR (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. RI Lee, Yong Hee/C-2015-2011 NR 4 TC 34 Z9 34 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 JAN 31 PY 1991 VL 27 IS 3 BP 216 EP 217 DI 10.1049/el:19910140 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA EX136 UT WOS:A1991EX13600016 ER PT J AU CLOSE, F AF CLOSE, F TI PARTICLE PHYSICS - GLUEBALLS AND EXOTIC MATTER SO NATURE LA English DT Editorial Material C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP CLOSE, F (reprint author), RUTHERFORD APPLETON LABS,DIDCOT OX11 0QH,ENGLAND. NR 3 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 JAN 31 PY 1991 VL 349 IS 6308 BP 368 EP 369 DI 10.1038/349368a0 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EV514 UT WOS:A1991EV51400024 ER PT J AU WALKER, WD WHITMORE, J TOOTHACKER, WS HILL, JC NEALE, WW LUCAS, P VOYVODIC, L AMMAR, R GRESS, J BISHOP, JM BISWAS, NN CASON, NM MATTINGLY, MCK RUCHTI, RC SHEPHARD, WD AF WALKER, WD WHITMORE, J TOOTHACKER, WS HILL, JC NEALE, WW LUCAS, P VOYVODIC, L AMMAR, R GRESS, J BISHOP, JM BISWAS, NN CASON, NM MATTINGLY, MCK RUCHTI, RC SHEPHARD, WD TI VECTOR BOSON PRODUCTION IN HADRON NUCLEAR COLLISIONS SO PHYSICS LETTERS B LA English DT Article ID MODEL AB We report a search for the production of light quark vector bosons in hadron-nucleus collisions at 100 GeV bombarding energy. We find surprisingly few of these resonances produced. The lack of these particles is though to be due to the absorption by the many modestly energetic nucleons and the few anti-nucleons in the final state. C1 PENN STATE UNIV,DEPT PHYS,ELEMENTARY PARTICLE SCI LAB,UNIVERSITY PK,PA 16802. PENN STATE UNIV,MONT ALTO CAMPUS,MT ALTO,PA. UNIV CAMBRIDGE,CAMBRIDGE CB3 0HE,ENGLAND. UNIV KANSAS,LAWRENCE,KS 66045. FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. UNIV NOTRE DAME,NOTRE DAME,IN 46556. RP WALKER, WD (reprint author), DUKE UNIV,DURHAM,NC 27706, USA. NR 8 TC 8 Z9 8 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 JAN 31 PY 1991 VL 255 IS 1 BP 155 EP 158 DI 10.1016/0370-2693(91)91158-R PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX925 UT WOS:A1991EX92500030 ER PT J AU FURENLID, LR RENNER, MW SZALDA, DJ FUJITA, E AF FURENLID, LR RENNER, MW SZALDA, DJ FUJITA, E TI EXAFS STUDIES OF NI(II), NI(I), AND NI(I)-CO, TETRAAZAMACROCYCLES AND THE CRYSTAL-STRUCTURE OF (5,7,7,12,14,14-HEXAMETHYL-1,4,8,11-TETRAAZACYCLOTETRADECA-4,11-DIENE)NI CKEL(I) PERCHLORATE SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PI-CATION RADICALS; X-RAY ABSORPTION; METHANOGENIC BACTERIA; LOW-SPIN; METHANOBACTERIUM-THERMOAUTOTROPHICUM; RHODOPSEUDOMONAS-VIRIDIS; CONFIGURATIONAL ISOMERS; NICKEL(II) PORPHYRINS; MACROCYCLIC COMPLEXES; MOLECULAR-STRUCTURE AB Nickel(II) complexes of tetraazamacrocycles undergo one-electron reduction to produce either a nickel(I) complex or a nickel(II) anion radical. Both reduced species react with CO. The nature of the parent Ni(II) complexes, the reduced species, and the Ni(I)-CO complexes were studied in CH3CN by means of EXAFS and UV-vis spectroscopy to characterize structural differences as a function of oxidation state and axial ligation of the metal in solution. The EXAFS results reveal that the reduction of Ni(II) to Ni(I) results not only in an expansion of the macrocycle core (0.1 angstrom change in Ni-N bond distance) but also a distortion. On the other hand, the Ni(II) to Ni(II) anion radical reduction leaves the geometry around the nickel atom unchanged. The anion radical of Ni(II) tetraene+ (NiL3+, L3 = 2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene) dimerizes in solution forming diamagnetic adducts. The monomer-dimer equilibrium constant was determined to be K1 = (5.5 +/- 1.0) x 10(4) M-1 from the electronic spectra. EXAFS data on CO adducts of Ni(I)L1,-L2, and -L3 (L1 = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene, L2 = 5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,14-diene) clearly indicate that these are five-coordinate complexes with a short Ni-C bond. Both Ni-N(imine) and Ni-N(amine) distances in the CO adducts of the Ni(I) complexes increase quite dramatically compared to those in the parent Ni(II) and Ni(I) complexes. The structure of the nickel(I) complex has been determined from single-crystal X-ray diffraction data collected by using Mo K-alpha radiation. Crystallographic data are as follows: space group P2/n with a = 15.717 (6) angstrom, b = 8.196 (2) angstrom, c = 16.049 (6) angstrom, beta = 100.67 (3) degrees, V = 2031 (2) angstrom3, Z = 4. The two square-planar nickel atoms in the asymmetric unit are situated on crystallographic inversion centers. The Ni-N(imine) are 1.988 (7) and 1.979 (7) angstrom and Ni-N(amine) distances are 2.063 (6) and 2.068 (6) angstrom, which are in good agreement with the EXAFS data. C1 BROOKHAVEN NATL LAB,DEPT APPL CHEM,UPTON,NY 11973. BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973. CUNY BERNARD M BARUCH COLL,DEPT NAT SCI,NEW YORK,NY 10010. RI Fujita, Etsuko/D-8814-2013 NR 97 TC 64 Z9 64 U1 2 U2 16 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 JAN 30 PY 1991 VL 113 IS 3 BP 883 EP 892 DI 10.1021/ja00003a023 PG 10 WC Chemistry, Multidisciplinary SC Chemistry GA EW178 UT WOS:A1991EW17800023 ER PT J AU WEI, BC AF WEI, BC TI A UNIFIED APPROACH TO FAILURE MODE, EFFECTS AND CRITICALITY ANALYSIS (FMECA) SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE FAILURE MODE; CRITICALITY ANALYSIS; FMECA AB The failure mode, effects, and criticality analysis (FMECA) is an essential function in design from concept through development. To be effective, the FMECA must be iterative to correspond with the nature of the design process itself. The information derived from a FMECA should have a major influence on the technical and economic viability of any major engineering projects by detailing where design changes or other corrective actions can lead to minimal downtime, the elimination of human hazards, and an improvement in system reliability and safety. The purpose of a FMECA is to provide a systematic, critical examination of potential failure modes of plants and equipment and their causes, to assess the safety of various systems or components, to analyze the effect of each failure mode on system operation, and to identify corrective action, i.e., design modifications. For an effective FMECA, the reporting must be thorough and accurate and must show results that can be interpreted easily by the top management to assist them in decision making processes. The usefulness of the FMECA as a design tool is dependent upon the effectiveness with which problem information is communicated for early design attention. FMECA should therefore be initiated as soon as preliminary design information is available at the higher system levels and extended to the lower levels as more information becomes available on the items in question. The FMECA is not only an essential task for reliability, it is also useful in maintainability, in maintenance plan analysis, and for failure detection and subsystem design. This paper presents a unified approach in performing FMECA applicable to large plant design. This procedure will assist the project contractors in performing a FMECA, and will aid the Owner organization in evaluating FMECA results and corrective actions. C1 US DOE,NE-46,WASHINGTON,DC 20545. NR 0 TC 6 Z9 8 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 260 EP 271 DI 10.1109/ARMS.1991.154445 PG 12 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300041 ER PT J AU PRAIRIE, RR ZIMMER, WJ AF PRAIRIE, RR ZIMMER, WJ TI STATISTICAL MODELING FOR PARTICLE IMPACT NOISE DETECTION TESTING SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE PIND TEST; RELIABILITY SCREENING; STOCHASTIC MATHEMATICAL MODEL; RELIABILITY DEMONSTRATION AND TESTING AB Particle Impact Noise Detection (PIND) testing is widely used to test electronic devices for the presence of conductive particles which can cause catastrophic failure. This paper develops a statistical model based on the rate of particles contaminating the part, the rate of particles induced by the test vibration, the escape rate, and the false alarm rate. Based on data from a large number of PIND tests for a canned transistor, the model is shown to fit the observed results closely. Knowledge of the parameters for which this fit is made is important in evaluating the effectiveness of the PIND test procedure and for developing background judgment about the performance of the PIND test. Furthermore, by varying the input parameters to the model, the resulting yield, failure rate and percent fallout can be examined and used to plan and implement PIND test programs. RP PRAIRIE, RR (reprint author), SANDIA NATL LABS,POB 5800,ALBUQUERQUE,NM 87185, USA. NR 0 TC 3 Z9 3 U1 2 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 SN 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 536 EP 540 DI 10.1109/ARMS.1991.154494 PG 5 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300091 ER PT J AU EASTERLING, RG MAZUMDAR, M SPENCER, FW AF EASTERLING, RG MAZUMDAR, M SPENCER, FW TI ON THE DESIGN OF COMPONENT TEST PLANS BASED ON SYSTEM RELIABILITY OBJECTIVES SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE SERIES SYSTEM; COMPONENT TESTING; OPERATING CHARACTERISTIC CURVE; SYSTEM RELIABILITY AB Component test plans are often designed by allocating a system's reliability goal among the system's components, then designing individual component test plans suitable for demonstrating achievement of each component's reliability goal. One use of the resulting component test data is the calculation of estimated system reliability, based on a model linking the component reliabilities to system reliability. The statistical precision of this system estimate depends on the component test plans (numbers of each component tested and the type of tests, e.g., variables or attributes) and, hence, is determined by the component test planners. Because system reliability may be of considerable interst, we feel an integrated view of component testing is required to assure that the ensemble of component tests will provide an adequate system reliability estimate. Let R* denote a selected system reliability estimator, based on component data. To characterize the precision of R* we use the function, Prob ( R* greater-than-or-equal-to R' \ R), where R' is a threshold that defines "test plan success" and R is system reliability. In general, this probability is a function of the vector of component reliabilities, not just the system reliability. In some cases, though, it is possible to bound this probability by identifying the combinations of component reliabilities that maximize and minimize Prob ( R* greater-than-or-equal-to R' \ R). Plotting these bounds as a function of R provides an "O.C. envelope" that characterizes the estimator, R*. By prespecifying points on this envelope, analogous to the producer's and consumer's risks in the conventional determination of sampling plans, one can determine the ensemble of component test plans that will provide a system reliability estimator for which the risks of a misleading estimate are purposively controlled. This paper considers the case of a series system of different components and binomial component data. For the case of equal numbers of units tested of each component (which can be shown to minimize total cost, subject to the risk constraints) the O.C. envelope is readily derived and from this envelope component test plans that satisfy the specified risks can be derived from equations that involve the cumulative binomial distribution function. Existing tables pertaining to acceptance sampling plans based on the bionomial distribution can be used to determine the required number of component tests. RP EASTERLING, RG (reprint author), SANDIA NATL LABS,DIV 7223,ALBUQUERQUE,NM 87185, USA. NR 0 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 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 592 EP 597 DI 10.1109/ARMS.1991.154504 PG 6 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300101 ER PT J AU PRINCE, BE HAIRE, MJ AF PRINCE, BE HAIRE, MJ TI THE INFLUENCE OF MAINTENANCE SYSTEM RELIABILITY AND MAINTAINABILITY CHARACTERISTICS ON PLANT AVAILABILITY SO PROCEEDINGS ANNUAL RELIABILITY AND MAINTAINABILITY SYMPOSIUM LA English DT Article; Proceedings Paper CT 1991 ANNUAL SYMP ON RELIABILITY AND MAINTAINABILITY CY JAN 29-31, 1991 CL ORLANDO, FL SP IEEE, AMER SOC QUAL CONTROL, SOC RELIAB ENGINEERS, SOC LOGIST ENGINEERS, SYST SAFETY SOC, INST IND ENGINEERS DE SYSTEM AVAILABILITY; MARKOV ANALYSIS; MODELING; MAINTENANCE DEFERRAL AB Performance goals for complex processes are often linked with achieving high availability of plant equipment. This requires that maintenance systems, which sometimes include complex electro-mechanical equipment operating in a hostile environment, meet certain requirements for reliability and maintainability. This paper develops several Markov probability models to evaluate the impact of maintenance system availability on the overall plant. The models considered included the case when the maintenance equipment is itself under repair when a failure occurs on process equipment. Examination was also given to the situation where the maintenance equipment is operated in a degraded condition (i.e., longer times are required to complete repairs). The results of the analysis identified conditions under which failures in the maintenance system could have a significant adverse effect on plant availability. Maintenance system failures affect the average times required for process repairs, which can affect the availability of each process subsystem in the plant. A useful simple rule for incorporating effects of maintenance system failures into plant availability estimates is to multiply repair rates corresponding to ideal conditions (no maintenance failures) by the expected availability of the maintenance system. This rule applies when the maintenance system is available on a standby status when a process failure occurs. The effect is somewhat greater when the maintenance equipment is subject to interim breakdowns, between process failures. The analysis also indicated conditions under which overall plant availability could benefit by permitting some degradation in maintenance equipment capabilities, before repairing this equipment with a backup system. As a rough rule, the degradation should not increase average repair times by more than about a factor of two. RP PRINCE, BE (reprint author), OAK RIDGE NATL LAB,BLDG 7601,M-S 6305,OAK RIDGE,TN 37831, USA. NR 0 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 0149-144X J9 P ANNU REL MAINT SYM JI Proc. Annu. Reliab. Maintainab. Symp. PD JAN 29 PY 1991 IS SYM BP 615 EP 623 DI 10.1109/ARMS.1991.154508 PG 9 WC Engineering, Multidisciplinary; Engineering, Industrial SC Engineering GA HK383 UT WOS:A1991HK38300105 ER PT J AU CHOW, WW KOCH, SW SARGENT, M ELL, C AF CHOW, WW KOCH, SW SARGENT, M ELL, C TI MANY-BODY EFFECTS ON THE LINEWIDTH ENHANCEMENT FACTOR IN QUANTUM-WELL LASERS SO APPLIED PHYSICS LETTERS LA English DT Article ID SEMICONDUCTOR-LASERS; SPECTRA; GAIN AB A many-body theory that includes band-gap renormalization, plasma screening, and interband Coulomb effects is used to calculate the linewidth enhancement factor alpha in quantum well lasers. We find significant variations in alpha with carrier density, suggesting that improvements in the laser linewidth and reduction in filamentation effects are possible for some laser configurations. C1 UNIV ARIZONA,CTR OPT SCI,TUCSON,AZ 85721. UNIV ARIZONA,DEPT PHYS,TUCSON,AZ 85721. UNIV FRANKFURT,INST THEORET PHYS,W-6000 FRANKFURT,GERMANY. RP CHOW, WW (reprint author), SANDIA NATL LABS,DIV 2531,ALBUQUERQUE,NM 87185, USA. NR 9 TC 19 Z9 19 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 28 PY 1991 VL 58 IS 4 BP 328 EP 330 DI 10.1063/1.104676 PG 3 WC Physics, Applied SC Physics GA EV460 UT WOS:A1991EV46000004 ER PT J AU LUO, L MUENCHAUSEN, RE MAGGIORE, CJ JIMENEZ, JR SCHOWALTER, LJ AF LUO, L MUENCHAUSEN, RE MAGGIORE, CJ JIMENEZ, JR SCHOWALTER, LJ TI GROWTH OF YBA2CU3O7-X THIN-FILMS ON SI WITH A COSI2 BUFFER LAYER SO APPLIED PHYSICS LETTERS LA English DT Article ID HETEROSTRUCTURES; BACKSCATTERING; SILICON AB By using the pulsed laser deposition technique, high-temperature superconducting YBa2Cu3O7-x(YBCO) films were grown on Si(001) with a 36 nm single-crystal <001> oriented CoSi2 buffer layer. The films, grown at a substrate temperature of approximately 700-degrees-C, have a metallic resistive temperature dependence with zero resistance at 85 K. X-ray diffraction, scanning electron microscopy, and ion channeling studies show that the YBCO films are polycrystalline but are strongly c-axis oriented normal to the Si substrate. Diffusion at the interface between the YBCO film and silicide buffer layer was minimized. This is essential to the growth of high-temperature superconducting films on Si substrates. C1 RENSSELAER POLYTECH INST,CTR INTEGRATED ELECTR,TROY,NY 12180. UNIV CALIF LOS ALAMOS SCI LAB,CTR EXPLORATORY RES & DEV,LOS ALAMOS,NM 87545. RENSSELAER POLYTECH INST,DEPT PHYS,TROY,NY 12180. RP LUO, L (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR MAT SCI,LOS ALAMOS,NM 87545, USA. NR 21 TC 17 Z9 17 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 28 PY 1991 VL 58 IS 4 BP 419 EP 421 DI 10.1063/1.104655 PG 3 WC Physics, Applied SC Physics GA EV460 UT WOS:A1991EV46000035 ER PT J AU GIVEON, A SMIT, DJ AF GIVEON, A SMIT, DJ TI SYMMETRIES ON THE MODULI SPACE OF (2,2) SUPERSTRING VACUA SO NUCLEAR PHYSICS B LA English DT Article ID FERMIONIC-STRING MODELS; SUPERCONFORMAL FIELD-THEORIES; CALABI-YAU MANIFOLDS; TIME SUPERSYMMETRY; K3 SURFACES; DUALITY; SINGULARITIES; COMPACTIFICATION; CLASSIFICATION; CONSTRUCTION AB Symmetries of the space of (2,2) string vacua for c = 3, 6, 9 are discussed in the context of orbifoldized Landau-Ginzburg theories. A general method for finding the maximal symmetry groups on the moduli space untwisted marginal operators is presented, by studying deformations of superpotentials. We give a complete discussion for the c = 3, 6 untwisted sectors. In particular we find non-abelian symmetry groups on the moduli space of c = 6 which are shown to correspond with automorphism groups of K3 surfaces. All these groups are subgroups of O(20, 4, Z). Some elements of these groups relate small volume target spaces to large ones. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,THEORET PHYS GRP,BERKELEY,CA 94720. RP GIVEON, A (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. NR 79 TC 15 Z9 15 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 JAN 28 PY 1991 VL 349 IS 1 BP 168 EP 206 DI 10.1016/0550-3213(91)90193-2 PG 39 WC Physics, Particles & Fields SC Physics GA ET178 UT WOS:A1991ET17800008 ER PT J AU SWENSON, JK BURGDORFER, J MEYER, FW HAVENER, CC GREGORY, DC STOLTERFOHT, N AF SWENSON, JK BURGDORFER, J MEYER, FW HAVENER, CC GREGORY, DC STOLTERFOHT, N TI COULOMB PATH INTERFERENCE IN LOW-ENERGY ION-ATOM COLLISIONS SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRON-EMISSION; TRANSITIONS; SCATTERING AB A new interference mechanism, analogous to "classic" double-slit electron scattering, has been identified in low-energy ion-atom collisions. This Coulomb "path" interference results from the existence of two trajectories, indistinguishable with respect to laboratory energy and emission angle, along which ejected autoionizing electrons may be scattered by the attractive Coulomb potential of the slowly receding spectator ion. A simple semiclassical description is presented. Calculated model line shapes are in excellent agreement with the strong angular dependence of the interference structure observed in the He-target 2s21S autoionizing line shape measured near 0-degrees following 10-keV He+ +He collisions. C1 UNIV TENNESSEE,KNOXVILLE,TN 37996. OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. NR 14 TC 22 Z9 22 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 28 PY 1991 VL 66 IS 4 BP 417 EP 420 DI 10.1103/PhysRevLett.66.417 PG 4 WC Physics, Multidisciplinary SC Physics GA EU786 UT WOS:A1991EU78600006 ER PT J AU EFTHIMION, PC MANSFIELD, DK STRATTON, BC SYNAKOWSKI, E BHATTACHARJEE, A BIGLARI, H DIAMOND, PH GOLDSTON, RJ HEGNA, CC MCCUNE, D REWOLDT, G SCOTT, S TANG, WM TAYLOR, G WALTZ, RE WIELAND, RM ZARNSTORFF, MC AF EFTHIMION, PC MANSFIELD, DK STRATTON, BC SYNAKOWSKI, E BHATTACHARJEE, A BIGLARI, H DIAMOND, PH GOLDSTON, RJ HEGNA, CC MCCUNE, D REWOLDT, G SCOTT, S TANG, WM TAYLOR, G WALTZ, RE WIELAND, RM ZARNSTORFF, MC TI OBSERVATION OF TEMPERATURE-DEPENDENT TRANSPORT IN THE TFTR TOKAMAK SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRAL-BEAM INJECTION; ENERGY CONFINEMENT; HEAT AB Local particle and heat transport coefficients have been measured in a temperature scan of neutral-beam-heated plasmas with n, I(p), and B-phi held constant. The electron transport is ascertained from a flux analysis of a small density perturbation, and the heat transport is obtained from the equilibrium power balance. The transport coefficients vary as T-(e)alpha where alpha = 1.5-2.5. The observed temperature dependence is predicted by numerical calculations of anomalous transport due to trapped-particle drift-type microinstabilities. RP EFTHIMION, PC (reprint author), PRINCETON PLASMA PHYS LAB,PRINCETON,NJ 08544, USA. NR 19 TC 57 Z9 57 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 JAN 28 PY 1991 VL 66 IS 4 BP 421 EP 424 DI 10.1103/PhysRevLett.66.421 PG 4 WC Physics, Multidisciplinary SC Physics GA EU786 UT WOS:A1991EU78600007 ER PT J AU GRANT, JB MCMAHAN, AK AF GRANT, JB MCMAHAN, AK TI REALISTIC ELECTRONIC-STRUCTURE CALCULATIONS FOR MAGNETIC INSULATORS LIKE LA2CUO4 SO PHYSICAL REVIEW LETTERS LA English DT Article ID HOLES; SUPERCONDUCTORS AB We suggest that Hartree-Fock theory is a good starting point for the solution of ab initio-derived extended Hubbard Hamiltonians for magnetic insulators like La2CuO4, as indicated by surprisingly accurate results for the superexchange frequencies and insulating gaps for this material and isostructural La2NiO4, K2CuF4, and K2NiF4. Limited configuration interaction beyond Hartree-Fock theory is then used to demonstrate that admixtures of a1 (d3z2-r2) symmetry states at energies somewhat away from the gap edge are essential to the dispersion of the first quasiparticle branch in La2CuO4 for doped-in holes. RP GRANT, JB (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 23 TC 67 Z9 67 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 JAN 28 PY 1991 VL 66 IS 4 BP 488 EP 491 DI 10.1103/PhysRevLett.66.488 PG 4 WC Physics, Multidisciplinary SC Physics GA EU786 UT WOS:A1991EU78600024 ER PT J AU NORTHRUP, JE HYBERTSEN, MS LOUIE, SG AF NORTHRUP, JE HYBERTSEN, MS LOUIE, SG TI MANY-BODY CALCULATION OF THE SURFACE-STATE ENERGIES FOR SI(111)2X1 SO PHYSICAL REVIEW LETTERS LA English DT Article ID BONDED CHAIN MODEL; SEMICONDUCTOR SURFACES; QUASIPARTICLE ENERGIES; ELECTRONIC-STRUCTURE; BAND-GAPS; X 1); SI(111)-(2X1); INSULATORS; 2X1; RECONSTRUCTION AB The surface-state excitation energies for the Si(111)2x1 surface have been calculated in the GW approximation. The energy position and the dispersion of the occupied and empty surface states are in excellent agreement with photoemission and inverse-photoemission experiments. The calculated quasiparticle surface-state band gap, 0.62 eV, is 0.15 eV larger than the measured onset energy for electron-hole pair excitations. The possibility that excitonic effects are responsible for this difference is examined. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. AT&T BELL LABS,MURRAY HILL,NJ 07974. RP NORTHRUP, JE (reprint author), XEROX CORP,PALO ALTO RES CTR,3333 COYOTE HILL RD,PALO ALTO,CA 94340, USA. NR 28 TC 111 Z9 111 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 JAN 28 PY 1991 VL 66 IS 4 BP 500 EP 503 DI 10.1103/PhysRevLett.66.500 PG 4 WC Physics, Multidisciplinary SC Physics GA EU786 UT WOS:A1991EU78600027 ER PT J AU BALTZ, AJ WENESER, J AF BALTZ, AJ WENESER, J TI A SOLUTION OF THE SOLAR-NEUTRINO PROBLEM - COMMENT SO PHYSICAL REVIEW LETTERS LA English DT Letter RP BALTZ, AJ (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 3 TC 16 Z9 16 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 28 PY 1991 VL 66 IS 4 BP 520 EP 520 DI 10.1103/PhysRevLett.66.520 PG 1 WC Physics, Multidisciplinary SC Physics GA EU786 UT WOS:A1991EU78600032 ER PT J AU LOMDAHL, PS OLSEN, OH SAMUELSEN, MR AF LOMDAHL, PS OLSEN, OH SAMUELSEN, MR TI TRANSVERSE INSTABILITIES IN A 3-DIMENSIONAL NONLINEAR CHAIN SO PHYSICS LETTERS A LA English DT Article ID SOLITARY EXCITATIONS; ALPHA-HELIX; DYNAMICS; LATTICE AB The influence of transverse fluctuations on the dynamics of longitudinal excitations in a non-linear three-dimensional (3D) chain is investigated. Analysis of the discrete as well as the continuum model shows that a transverse fluctuation is coupled to the longitudinal direction except in a specific case. Further, it is found that a hard core nature of the potential will favor the longitudinal motion while the transverse motion tends to disturb the longitudinal motion. The present investigation shows that although a propagating pulse has a focusing ability it is extremely sensitive to transverse fluctuation. C1 UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545. RP LOMDAHL, PS (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 12 TC 11 Z9 11 U1 0 U2 1 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 JAN 28 PY 1991 VL 152 IS 7 BP 343 EP 348 DI 10.1016/0375-9601(91)90735-Q PG 6 WC Physics, Multidisciplinary SC Physics GA EX481 UT WOS:A1991EX48100007 ER PT J AU SZASZ, A KOPAEV, YA DASGUPTA, A AF SZASZ, A KOPAEV, YA DASGUPTA, A TI ON THE ELECTRONIC STRUCTURE-DRIVEN PAIRING MECHANISM IN HIGH-TC SUPERCONDUCTORS SO PHYSICS LETTERS A LA English DT Article ID DENSITY AB A relation between the special electronic structure and short-range collective coherent fluctuations in high-T(c) superconductive materials is suggested. A possible pairing mechanism is discussed. C1 PN LEBEDEV PHYS INST, MOSCOW 117924, USSR. US DOE, CHICAGO OPERAT OFF, ARGONNE, IL 60439 USA. RP SZASZ, A (reprint author), EOTVOS LORAND UNIV, SURFACE & INTERFACE PHYS LAB, MUZEUM KRT 6-8, H-1088 BUDAPEST, HUNGARY. NR 44 TC 3 Z9 3 U1 0 U2 0 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 JAN 28 PY 1991 VL 152 IS 7 BP 361 EP 366 DI 10.1016/0375-9601(91)90739-U PG 6 WC Physics, Multidisciplinary SC Physics GA EX481 UT WOS:A1991EX48100011 ER PT J AU CURTISS, LA BIERWAGEN, E AF CURTISS, LA BIERWAGEN, E TI BONDING OF A WATER MOLECULE TO A COPPER ATOM SO CHEMICAL PHYSICS LETTERS LA English DT Article ID TRANSITION-METAL ATOMS; ELECTRON CORRELATION; BASIS SETS; ROW ATOMS; H2O; COMPLEXES; ADSORPTION; LIGANDS; RU(001); NH3 AB Ab initio molecular orbital calculations, including correlation effects and large basis sets, have been carried out on the interaction of a single Cu atom with a water molecule, Cu...OH2. The H2O molecule is found to be bound to Cu by 0.20 eV with nearly all of the binding coming at the correlation level. This is reduced to about 0.15 eV if correction for basis set superposition error is included. The shift in the bending frequency of water in the complex has been calculated and is in good agreement with the observed shift of this complex trapped in a low-temperature matrix. Results are also presented for the interaction of a Cu atom with two water molecules to assess the nonadditivity of the interaction. C1 ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. RP CURTISS, LA (reprint author), ARGONNE NATL LAB, DIV CHEM TECHNOL, 9700 S CASS AVE, ARGONNE, IL 60439 USA. NR 24 TC 13 Z9 13 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 JAN 25 PY 1991 VL 176 IS 5 BP 417 EP 422 DI 10.1016/0009-2614(91)90230-7 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EX467 UT WOS:A1991EX46700003 ER PT J AU MO, G SUNG, CC RITCHIE, RH AF MO, G SUNG, CC RITCHIE, RH TI BOUND-STATES OF ELECTRONS IN THE VICINITY OF A DIELECTRIC SPHERE SO CHEMICAL PHYSICS LETTERS LA English DT Article ID MOLECULAR CLUSTERS; WATER; ATTACHMENT; POLYMERS; SURFACE; MODEL AB The binding energy of a hydrated electron in the vicinity of a water cluster is considered. Our consistent quantum-mechanical treatment results in an effective potential different form the classical image potential. Various approximate forms of the dielectric function are tested and compared. C1 OAK RIDGE NATL LAB,DIV HLTH & SAFETY RES,OAK RIDGE,TN 37830. RP MO, G (reprint author), UNIV ALABAMA,DEPT PHYS,HUNTSVILLE,AL 35899, USA. NR 19 TC 5 Z9 5 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 JAN 25 PY 1991 VL 176 IS 5 BP 433 EP 438 DI 10.1016/0009-2614(91)90233-Y PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EX467 UT WOS:A1991EX46700006 ER PT J AU WILSON, K COLLART, FR HUBERMAN, E STRINGER, JR ULLMAN, B AF WILSON, K COLLART, FR HUBERMAN, E STRINGER, JR ULLMAN, B TI AMPLIFICATION AND MOLECULAR-CLONING OF THE IMP DEHYDROGENASE GENE OF LEISHMANIA-DONOVANI SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID SYNTHETASE-DIHYDROFOLATE REDUCTASE; RESISTANT LEISHMANIA; MYCOPHENOLIC-ACID; DNA AMPLIFICATION; DRUG-RESISTANCE; VISCERAL LEISHMANIASIS; PLASMODIUM-FALCIPARUM; TRITRICHOMONAS-FOETUS; SODIUM STIBOGLUCONATE; PURINE METABOLISM AB A mutant (MPA100) strain of Leishmania donovania was generated from a wild type (D1700) population by virtue of its ability to survive the selective pressure of gradually increasing concentrations of mycophenolic acid (MPA), an inhibitor of IMP dehydrogenase (IMPDH) activity. Comparative growth experiments revealed that the MPA100 strain was 100-fold more resistant to MPA toxicity and cross-resistant to ribavarin, another inhibitor of IMPDH. A direct comparison of IMPDH levels in D1700 and MPA100 cells showed that the latter expressed at least 20-fold higher enzyme activity. In order to evaluate the mechanism by which MPA100 cells overexpressed IMPDH, the leishmanial gene encoding IMPDH was isolated from a genomic library in EMBL3 by cross-hybridization to a mouse IMPDH cDNA, and a 2.3-kilobase EcroRV-PstI fragment was subcloned into a Bluescript vector and sequenced. The EcoRV-PstI fragment contained an open reading frame of 514 amino acids that encompassed the entire leishmanial IMPDH coding sequence. The predicted amino acid sequence showed a 52.5% identity with that of the corresponding human IMPDH. The codon usage of the leishmanial IMPDH gene reflected a strong bias toward condons containing either G or C in the wobble position. The EcoRV-PstI fragment hybridized to a 3.0-kilobase mRNA that was expressed at 10-20-fold greater levels in the MPA100 cells. Using the EcoRV-PstI fragment as a probe, the increased amount of IMPDH activity and IMPDH mRNA in the MPA100 cells could be attributed to an approximately 10-20-fold amplification of the leishmanial IMPDH gene. C1 OREGON HLTH SCI UNIV,DEPT BIOCHEM & MOLEC BIOL,PORTLAND,OR 97201. ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. UNIV CINCINNATI,MED CTR,DEPT MOLEC GENET BIOCHEM & MICROBIOL,CINCINNATI,OH 45267. OI Collart, Frank/0000-0001-6942-4483 FU NIAID NIH HHS [AI23682] NR 58 TC 69 Z9 73 U1 0 U2 2 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 JAN 25 PY 1991 VL 266 IS 3 BP 1665 EP 1671 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EU497 UT WOS:A1991EU49700049 PM 1671039 ER PT J AU MELENDRES, CA YOU, H MARONI, VA NAGY, Z YUN, W AF MELENDRES, CA YOU, H MARONI, VA NAGY, Z YUN, W TI SPECULAR X-RAY REFLECTION FOR THE INSITU STUDY OF ELECTRODE SURFACES SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Note ID SCATTERING C1 ARGONNE NATL LAB,DIV ADV PHOTON SOURCE,ARGONNE,IL 60439. RP MELENDRES, CA (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI You, Hoydoo/A-6201-2011 OI You, Hoydoo/0000-0003-2996-9483 NR 10 TC 17 Z9 17 U1 0 U2 0 PU ELSEVIER SCIENCE SA LAUSANNE PI LAUSANNE 1 PA PO BOX 564, 1001 LAUSANNE 1, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JAN 25 PY 1991 VL 297 IS 2 BP 549 EP 555 DI 10.1016/0022-0728(91)80051-Q PG 7 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA EY387 UT WOS:A1991EY38700020 ER PT J AU YOKOBATA, K TRENCHAK, B DEJONG, PJ AF YOKOBATA, K TRENCHAK, B DEJONG, PJ TI RESCUE OF UNSTABLE COSMIDS BY INVITRO PACKAGING SO NUCLEIC ACIDS RESEARCH LA English DT Note ID ESCHERICHIA-COLI; DNA; LAMBDA C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,DIV BIOMED SCI,CTR HUMAN GENOME,L-452,LIVERMORE,CA 94550. NR 9 TC 12 Z9 12 U1 0 U2 0 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 JAN 25 PY 1991 VL 19 IS 2 BP 403 EP 404 DI 10.1093/nar/19.2.403 PG 2 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EV868 UT WOS:A1991EV86800033 PM 2014178 ER PT J AU BAKKER, MG TRIFUNAC, AD AF BAKKER, MG TRIFUNAC, AD TI RADICAL IONS IN CONDENSED PHASE PRODUCED BY 2-PHOTON IONIZATION - A STUDY OF GEMINATE RECOMBINATION BY FLUORESCENCE DETECTED MAGNETIC-RESONANCE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID PULSE-RADIOLYSIS; MONOPHOTONIC IONIZATION; TIME; KINETICS; LIQUID; PHOTOIONIZATION; SPECTROSCOPY; ALCOHOLS; CATIONS; STATE AB Geminate radical ions produced in laser photoionization of aromatic compounds in 2-propanol were studied by fluorescence detected magnetic resonance (FDMR). This optical detection of magnetic resonance of transient radical ions allows identification of radical ions via hyperfine coupling parameters and determination of spin multiplicity of the radical ion pairs and thus the multiplicity of the precursor states. In all molecules studied, it was found that photoionization occurs predominantly from singlet state. Laser power dependence studies of anthracene and TMPD (N,N,N',N'-tetramethyl-p-phenylenediamine) both show two-photon ionization with intense 308-nm light. By use of known photophysical parameters, the laser power dependence of the FDMR signal could be satisfactorily modeled on the basis of sequential, two-photon ionization through the first excited singlet state. C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. UNIV ALABAMA,DEPT CHEM,TUSCALOOSA,AL 35487. NR 36 TC 15 Z9 15 U1 0 U2 2 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 JAN 24 PY 1991 VL 95 IS 2 BP 550 EP 555 DI 10.1021/j100155a012 PG 6 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600012 ER PT J AU RABINOWITZ, MJ SUTHERLAND, JW PATTERSON, PM KLEMM, RB AF RABINOWITZ, MJ SUTHERLAND, JW PATTERSON, PM KLEMM, RB TI DIRECT RATE-CONSTANT MEASUREMENTS FOR H+CH4-]CH3+H-2, 897-1729-K, USING THE FLASH-PHOTOLYSIS SHOCK-TUBE TECHNIQUE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID H-2 REVERSIBLE CH4+H; RESONANCE-ABSORPTION; RATE COEFFICIENT; RATE PARAMETERS; + H; TEMPERATURE; METHANE; CH3; DECOMPOSITION; PRESSURE AB A kinetic study of the reaction of hydrogen atoms with methane was performed using the Brookhaven flash photolysis-shock tube (FP-ST) facility. Experiments were conducted in the reflected shock regime over the temperature range 897-1729 K under pseudo-first-order conditions ([CH4]/[H] greater-than-or-equal-to 200). Hydrogen atoms were monitored by using atomic resonance absorption and rate constants were derived directly from decays of absorbance signals. Separate experiments, in which the initial H-atom and radical concentrations were varied, demonstrated the absence of kinetic complications due to secondary reactions. This observations was further verified by the results of a computer modeling study. The rate constant values obtained in this research may be fitted with equal uncertainty to either a two-parameter expression, k1(T) = (1.78 +/- 0.12) x 10(-10) exp[-(6440 +/- 80) K/T)], or three-parameter expression, k1(T) = 1.6 x 10(-19)T2.57 +/- 0.76 exp[-(3340 +/- 920) K/T]. Units are cm3 molecule-1 s-1 with uncertainties quoted at the one standard deviation level. The preexponential term for the three-parameter expression and its uncertainty are given in logarithmic form: In (A) = -43.3 +/- 6.2. The mean deviation of the data from either expression is about +/- 10% over the entire temperature range. Rate constants for the reverse reaction, k-1(T), were computed from our measured k1(T) values, using the equilibrium constant for reaction 1, at each experimental temperature. These data were also fitted to both two-parameter and three-parameter expressions with equal uncertainty. Combining the present FP-ST data with those obtained in flow tube experiments (by Kurylo, Hollinder, and Timmons), expressions for k1(T) and k1(T) are evaluated for the temperature span 400 K less-than-or-equal-to T less-than-or-equal-to 1800 K: k1(T) = 6.4 x 10(-18)T2.11 +/- 0.18 exp[-(3900 +/- 140) K/T] cm3 molecule-1 s-1 and k-1(T) = 6.6 x 10(-20)T2.24 +/- .18 exp[-(3220 +/- 140) K/T] cm3 molecule-1 s-1. The data of this study are compared with previous experimental and theoretical results. For example, good agreement is found between the data reported here for k1(T) and the calculated values reported by Truhlar and co-workers; but there is a discrepancy between the present results and the values recommended by Warnatz C1 BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973. NR 45 TC 70 Z9 70 U1 0 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 JAN 24 PY 1991 VL 95 IS 2 BP 674 EP 681 DI 10.1021/j100155a033 PG 8 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600033 ER PT J AU JONAH, CD SAUER, MC COOPER, R AF JONAH, CD SAUER, MC COOPER, R TI TIME-RESOLVED MEASUREMENT OF G-VALUES OF SOLUTE EXCITED-STATES IN CYCLOHEXANE AND NORMAL-HEXANE SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID PULSE-RADIOLYSIS; SINGLET-STATES; YIELDS; FLUORESCENCE; BENZENE; IONS AB The number of solute excited states produced per 100 eV absorbed is determined for several scintillators dissolved in cyclohexane and n-hexane over the concentration range 0.001-0.05 M. These yields are determined at 5 ns after a 30-ps pulse of electrons. The part of the yield arising from excitation of the solute by absorption of Cerenkov light is determined on the basis of solutions of scintillators in ethanol, where essentially all of the solute excited state results from this process. RP JONAH, CD (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 17 TC 5 Z9 5 U1 0 U2 5 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 JAN 24 PY 1991 VL 95 IS 2 BP 728 EP 730 DI 10.1021/j100155a044 PG 3 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600044 ER PT J AU SAUER, MC JONAH, CD NALEWAY, CA AF SAUER, MC JONAH, CD NALEWAY, CA TI STUDY OF THE REACTIONS OF GEMINATE IONS IN IRRADIATED SCINTILLATOR, HYDROCARBON SOLUTIONS USING RECOMBINATION FLUORESCENCE AND STOCHASTIC SIMULATIONS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID PICOSECOND PULSE-RADIOLYSIS; EXTERNAL ELECTRIC-FIELD; EXCITED-STATE FORMATION; LIQUID CYCLOHEXANE; SATURATED-HYDROCARBON; NONPOLAR LIQUIDS; SEPARATION DISTANCES; COMPUTER-SIMULATION; SINGLET-STATES; POSITIVE-ION AB The fluorescence from electron beam pulse irradiated solutions of scintillators in n-hexane and cyclohexane has been measured. The experimental fluorescence vs time is compared to calculations utilizing a stochastic Monte Carlo model, in which three different distribution functions were tested to describe the initial electron-solvent.+ separation distance. This comparison indicates that the recombination fluorescence is markedly affected by fast reactions of the solvent radical cations, most likely proton transfer to the solvent, which prohibit eventual formation of the fluorescent state of the scintillator via ion recombination reactions. Results bearing on the contribution of energy transfer from the solvent-excited state to the scintillator are also presented. Measured G values of the fluorescent state of the scintillator are considerably lower than those calculated from the model, and possible reasons for this are discussed. RP SAUER, MC (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. NR 52 TC 29 Z9 29 U1 1 U2 5 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 JAN 24 PY 1991 VL 95 IS 2 BP 730 EP 740 DI 10.1021/j100155a045 PG 11 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600045 ER PT J AU DUPLATRE, G JONAH, CD AF DUPLATRE, G JONAH, CD TI EFFECT OF ION-PAIRING ON ELECTRON SCAVENGING AND SOLVATED ELECTRON YIELD ENHANCEMENT IN METHANOL - A COMPARISON BETWEEN PULSE-RADIOLYSIS AND POSITRON LIFETIME SPECTROSCOPIC DATA SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID AQUEOUS-SOLUTIONS; ANNIHILATION TECHNIQUES; SOLVENT INTERACTIONS; INHIBITION; LIQUIDS; MIXTURES; NITRATE; WATER AB The influence of ion pairing on electron scavenging in nitrate solutions and the effect of amines on the enhancement of the electron yield, two particular processes previously observed in positron annihilation (PA) studies on positronium (Ps) formation in methanol, are examined by using picosecond pulse radiolysis (PR). These studies show that the scavenging of the precursors of the solvated electron (e(sol)- does not depend on ion pairing while confirming previous results that ion pairing strongly affects the reaction of e(sol)- with LiNO3 and NH4NO3. The results from positronium annihilation studies agree with the precursor scavenging results for NO3- and NH4NO3; however, LiNO3 is a weaker electron scavenger. No increase in the initial e(sol)- yield is detected in PR in the presence of amines, whereas the Ps yield is significantly increased. These apparent differences can be explained if one considers the importance of the trap depth for the electron, whether it has been captured by a solute (LiNO3) or it has recombined with the positive ion (amines). In either case, in PR, the electron is lost for the free e(sol)- yield. In PA on the contrary, if both types of traps are shallow enough, the electron can still be picked off by the positron to form Ps. C1 ARGONNE NATL LAB, DIV CHEM, ARGONNE, IL 60439 USA. CTR RECH NUCL, CHIM NUCL LAB, F-67037 STRASBOURG, FRANCE. NR 34 TC 11 Z9 11 U1 2 U2 4 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 JAN 24 PY 1991 VL 95 IS 2 BP 897 EP 901 DI 10.1021/j100155a074 PG 5 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600074 ER PT J AU NYDEN, MR NOID, DW AF NYDEN, MR NOID, DW TI MOLECULAR-DYNAMICS OF INITIAL EVENTS IN THE THERMAL-DEGRADATION OF POLYMERS SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID COMPUTER-SIMULATION AB Computer simulations, based on molecular dynamics, were used to investigate the kinetic stability of model polymers as a function of temperature, secondary structure, and molecular weight. The rate constants for random scission of the carbon-carbon bonds were obtained from simulations starting from both planar zigzag and coiled conformations. The coiled polymers were found to be more stable than planar zigzag polymers with the same primary structure. The computer-generated rates correlated reasonably well with the functional predictions of the Rice, Ramsperger, and Kassel theory of unimolecular reactivity; however, deviations were observed for some of the short-chained polymers. Computer movies revealed pronounced coiling in the vicinity of dissociating bonds. This behavior was examined in light of proposed mechanisms for intramolecular hydrogen transfer. C1 OAK RIDGE NATL LAB,DIV CHEM,OAK RIDGE,TN 37831. RP NYDEN, MR (reprint author), NATL INST STAND & TECHNOL,CTR FIRE RES,GAITHERSBURG,MD 20899, USA. NR 18 TC 23 Z9 25 U1 0 U2 4 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 JAN 24 PY 1991 VL 95 IS 2 BP 940 EP 945 DI 10.1021/j100155a081 PG 6 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600081 ER PT J AU LAFEMINA, JP ARJAVALINGAM, G AF LAFEMINA, JP ARJAVALINGAM, G TI PHOTOPHYSICS OF POLY(ETHYLENE-TEREPHTHALATE) - ULTRAVIOLET-ABSORPTION AND EMISSION SO JOURNAL OF PHYSICAL CHEMISTRY LA English DT Article ID ELECTRONIC-STRUCTURE; POLY(ETHYLENE-TEREPHTHALATE) FILMS; POLYETHYLENE TEREPHTHALATE; LASER-RADIATION; FLUORESCENCE; ORIENTATION; POLYIMIDE; SPECTROSCOPY; POLYMERS; SPECTRA AB Polarized and unpolarized emission spectra for poly(ethylene terephthalate) are presented, and a new phosphorescence peak at 564 nm is reported. The spectroscopically parametrized CNDO/S3 model is used to provide a detailed description of the absorption and monomeric emission. Moreover, preliminary computations on an idealized terephthalate dimer indicate that the 368-nm fluorescence and the newly reported phosphorescence emission may be attributable to an associated ground-state dimer. C1 IBM CORP, THOMAS J WATSON RES CTR, YORKTOWN HTS, NY 10598 USA. RP LAFEMINA, JP (reprint author), PACIFIC NW LAB, POB 999, RICHLAND, WA 99352 USA. NR 62 TC 19 Z9 19 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 JAN 24 PY 1991 VL 95 IS 2 BP 984 EP 988 DI 10.1021/j100155a090 PG 5 WC Chemistry, Physical SC Chemistry GA EU486 UT WOS:A1991EU48600090 ER PT J AU ERSKINE, DJ NELLIS, WJ AF ERSKINE, DJ NELLIS, WJ TI SHOCK-INDUCED MARTENSITIC PHASE-TRANSFORMATION OF ORIENTED GRAPHITE TO DIAMOND SO NATURE LA English DT Article ID PARAMETERS; CARBON AB ONE important method of diamond synthesis is shock compression of graphite and other forms of carbon to high pressures and temperatures, and subsequent quenching to yield metastable diamond. This process, which occurs in microseconds, happens naturally in the impact of meteors 1,2, within products of explosives 3,4, and by explosive compression of powders 5,6. A major unresolved issue is whether the shock-induced phase transition of graphite to diamond is martensitic of diffusive. The relation between the crystal structures of graphite and hexagonal diamond suggests that the phase transition should be fast and martensitic if shock pressure is applied parallel to the c axis (normal to the basal planes) of the graphite crystal structure. Here we report measurements of shock-wave histories for this transition which show that it occurs in approximately 10 ns. These results imply that the transformation from graphite to diamond is martensitic for temperatures substantially lower than the melting temperature. We observe an unexpectedly large sensitivity of kinetics to sample morphology. As well as answering questions concerning the physical nature of the transformation, our results are relevant to optimization of diamond yield in industrial synthetic methods. RP ERSKINE, DJ (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 26 TC 97 Z9 100 U1 2 U2 28 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JAN 24 PY 1991 VL 349 IS 6307 BP 317 EP 319 DI 10.1038/349317a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EU501 UT WOS:A1991EU50100047 ER PT J AU CHOMAZ, P BURGIO, GF RANDRUP, J AF CHOMAZ, P BURGIO, GF RANDRUP, J TI INCLUSION OF FLUCTUATIONS IN NUCLEAR-DYNAMICS SO PHYSICS LETTERS B LA English DT Article ID COLLISIONS AB In this letter we present a new method to include fluctuations into dynamical simulations of the Nordheim type, in which individual nucleons moving in their self-consistent mean field experience Pauli-blocked two-body collisions. The method consists of including a suitably scaled amount of noise in the basic two-body scattering process. The method is illustrated for a gas of fermions on a two-dimensional torus and the results exhibit the desired behavior: the mean phase-space occupancy relaxes towards the appropriate Fermi-Dirac distribution, the associated variance evolves as expected from quantum statistics, and the covariance reflects the various correlations inherent in the two-body collision process. RP CHOMAZ, P (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL SCI,BERKELEY,CA 94720, USA. NR 9 TC 79 Z9 79 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JAN 24 PY 1991 VL 254 IS 3-4 BP 340 EP 346 DI 10.1016/0370-2693(91)91166-S PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX593 UT WOS:A1991EX59300008 ER PT J AU KOSOWER, DA AF KOSOWER, DA TI THE SPINOR HELICITY METHOD IN DIMENSIONAL REGULARIZATION SO PHYSICS LETTERS B LA English DT Article ID MULTI-GLUON SCATTERING; GAUGE-THEORIES; BREMSSTRAHLUNG; AMPLITUDES AB I present a rule for computing dimensionally-regularized amplitudes within the frame-work of the spinor-helicity method, along with explicit examples for the four- and five-gluon amplitudes. C1 SWISS FED INST TECHNOL,CH-8093 ZURICH,SWITZERLAND. RP KOSOWER, DA (reprint author), FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 20 TC 16 Z9 16 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 JAN 24 PY 1991 VL 254 IS 3-4 BP 439 EP 443 DI 10.1016/0370-2693(91)91182-U PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX593 UT WOS:A1991EX59300024 ER PT J AU KERBY, MC EICHHORN, BW DOVIKEN, L VOLLHARDT, KPC AF KERBY, MC EICHHORN, BW DOVIKEN, L VOLLHARDT, KPC TI ACTIVATED MOLYBDENUM MOLYBDENUM QUADRUPLE BONDS .2. 1ST EXAMPLE OF ALKYNE ADDITIONS TO METAL METAL QUADRUPLE BONDS SO INORGANIC CHEMISTRY LA English DT Note ID CHEMISTRY; ALKOXIDES; ION C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CHEM,DIV MAT & CHEM SCI,BERKELEY,CA 94720. UNIV MARYLAND,DEPT CHEM & BIOCHEM,COLLEGE PK,MD 20742. RP KERBY, MC (reprint author), EXXON RES & DEV LABS,POB 2226,BATON ROUGE,LA 70821, USA. NR 15 TC 15 Z9 15 U1 2 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JAN 23 PY 1991 VL 30 IS 2 BP 156 EP 158 DI 10.1021/ic00002a003 PG 3 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EU669 UT WOS:A1991EU66900003 ER PT J AU HEINRICH, DD FOLTING, K HUFFMAN, JC REYNOLDS, JG CHRISTOU, G AF HEINRICH, DD FOLTING, K HUFFMAN, JC REYNOLDS, JG CHRISTOU, G TI PREPARATION AND PROPERTIES OF MONONUCLEAR VANADIUM THIOLATES - STRUCTURAL CHARACTERIZATION OF THE [V(SBUT)4]0,- PAIR AND C-S BOND-CLEAVAGE IN V(SBUT)4 IN THE GAS-PHASE SO INORGANIC CHEMISTRY LA English DT Article ID ELECTRON-PARAMAGNETIC RESONANCE; HYDROTREATING CATALYSTS; SULFUR-COMPOUNDS; FOSSIL-FUELS; COMPLEXES; CHEMISTRY; METAL; PETROLEUM; DEMETALLIZATION; PHTHALOCYANINE AB The synthesis and properties of mononuclear vanadium complexes with Bu(t)S- ligation are reported. Treatment of VCl3(THF)3 with NaSBu(t) and Bu(t)SSBu(t) in MeCN leads to high-yield isolation of V(SBu(t))4 (1). In contrast, treatment of VCl3(THF)3 with NaSBu(t) and 2,2'-bipyridine (bpy) leads to the V(III) salt [V(SBu(t))2(bpy)2][V(SBu(t))4] (2). Complex 1 crystallizes in space group P4BAR2(1)c with (at - 158-degrees-C) a = b = 11.034 (12) angstrom, c = 9.253 (9) angstrom, and Z = 2. Complex 2 crystallizes in space group P2(1)/n with (at - 142-degrees-C) a = 21.309 (9) angstrom, b = 15.592 (6) angstrom, c = 17.151 (7) angstrom, and Z = 4. The structures of 1 and 2 were solved by using 483 (F > 3.0-sigma-(F) and 2102 (F > 2.0-sigma-(F)) unique reflections in the range 6-degrees less-than-or-equal-to 2-theta less-than-or-equal-to 45-degrees and refined to values of R(R(w)) of 3.96 (4.00) and 8.54% (7.69%), respectively. The structure of 1 consists of a mononuclear four-coordinate V(SBu(t))4 unit with imposed 4BAR (S4) symmetry, corresponding to a slight flattening from T(d) symmetry. The V-S distances are 2.2184 (24) angstrom. Complex 2 contains an anion that is the one-electron-reduced version of 1; there is no imposed symmetry, but the geometry can be again described as distorted tetrahedral. The V-S bonds (2.280(7)-2.309 (7) angstrom) are slightly longer than those in 1, as expected for the lower oxidation state. The cation geometry of 2 is distorted octahedral with two chelating bpy groups and two Bu(t)S- ligands in cis positions. Complex 1 was investigated by cyclic voltammetry (CV) in CH2Cl2; it was found to undergo a reversible one-electron reduction at -0.68 V vs SCE and an irreversible one-electron oxidation at +0.81 V. The EPR spectrum of 1 in toluene solution at room temperature shows a typical eight-line hyperfine-structured signal with g(iso) = 1.970 and A(iso) = 55 G. At 163 K in a toluene glass, an axially symmetric spectrum is obtained with g parallel-to = 1.961, g perpendicular-to = 1.975, A parallel-to 108 G, and A perpendicular-to = 28 G; these parameters are compared to those for V(OBu(t))4 and differences shown to be as expected for the O vs S substitution. The electron ionization mass spectral (EIMS) behavior of 1 has been investigated and its fragmentation pattern elucidated. The major fragmentation modes involve sequential loss of C4H9 by C-S bond cleavage to yield [V(SBu(t))(4-x)S(x)]+ (x = 0-4) ions and S atom loss leading to ions of general formulation [V(SC4H9)(x)S(y)]+ (x = 1, 2; y = 1, 2) and [VS(x)]+ (x = 0-3). No evidence for one-step loss of an entire SC4H9 fragment is observed. The relevance of these results to several catalytic processes in the petroleum industry are described, including the mechanism by which V2S3 is formed during upgrading of heavy crudes containing vanadyl impurities and the use of colloidal VS(x) particles as hydrodesulfurization catalysts in slurry-type processes. C1 UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. INDIANA UNIV,DEPT CHEM,BLOOMINGTON,IN 47405. INDIANA UNIV,CTR MOLEC STRUCT,BLOOMINGTON,IN 47405. RI Christou, George /A-3072-2014 NR 45 TC 30 Z9 30 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JAN 23 PY 1991 VL 30 IS 2 BP 300 EP 305 DI 10.1021/ic00002a027 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EU669 UT WOS:A1991EU66900027 ER PT J AU VANDERSLUYS, LS KUBATMARTIN, KA KUBAS, GJ CAULTON, KG AF VANDERSLUYS, LS KUBATMARTIN, KA KUBAS, GJ CAULTON, KG TI PROTONATION OF W(CO)3(PCY3)2 SO INORGANIC CHEMISTRY LA English DT Article ID MOLECULAR-HYDROGEN COMPLEXES; TRANSITION-METALS; CRYSTAL; EQUILIBRIUM; PRECURSORS; LIGAND AB Protonation of W(CO)3(PCy3)2 with equimolar HBF4.OEt2 in toluene produces WH(BF4)(CO)3(PCy3)2. This was characterized by spectroscopic methods and single-crystal X-ray diffraction as a seven-coordinate molecule with eta-1-coordinated BF4-. The location of the hydride, in the WFP2CO plane and in the cis position relative to one P and CO, makes the phosphines inequivalent. This inequivalence is evident in both the P-31 and H-1 NMR spectra, but the onset of hydride fluxionality is detected already at 25-degrees-C. The low-temperature F-19 NMR spectrum and also the comparison of the spectral data of this molecule to that of the analogous products from HO3SCF3, H2C(SO2CF3)2, and HCl.Et2O indicate that the conjugate base of the acid employed for protonation remains coordinated in aromatic solvents. Reactivity studies of W(CO)3P2 with BF4- are consistent with the idea that the overall protonation reaction of 16-electron W(CO)3(PCy3)2 is initiated by proton transfer, not by coordination of a lone pair of the conjugate base (e.g., BF4- or OEt2). C1 INDIANA UNIV,DEPT CHEM,BLOOMINGTON,IN 47405. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NR 21 TC 23 Z9 23 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD JAN 23 PY 1991 VL 30 IS 2 BP 306 EP 310 DI 10.1021/ic00002a028 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA EU669 UT WOS:A1991EU66900028 ER PT J AU PARK, JW SAUER, K AF PARK, JW SAUER, K TI SUBUNIT SELECTIVE BLEACHING OF C-PHYCOCYANIN FROM SYNECHOCOCCUS PCC-6301 STRAIN AN-112 BY CU2+ AND SODIUM-PERCHLORATE SO BIOCHIMICA ET BIOPHYSICA ACTA LA English DT Article DE PHOTOSYNTHESIS; PHYCOCYANIN; SUBUNIT SPECTRUM; BLEACHING; COPPER COMPLEX ID CYANOBACTERIUM MASTIGOCLADUS-LAMINOSUS; RESOLVED FLUORESCENCE SPECTROSCOPY; CRYSTAL-STRUCTURE DATA; BLUE-GREEN-ALGAE; AGMENELLUM-QUADRUPLICATUM; ANABAENA-VARIABILIS; PROTEIN INTERACTION; ENERGY-TRANSFER; BETA SUBUNITS; BILE-PIGMENTS AB The bleaching of the monomer and the separated alpha and beta-subunits of C-phycocyanin from Synechococcus PCC 6301 Strain AN 112 by Cu2+ has been investigated. Upon the addition of Cu2+, the visible absorption band of the alpha-beta monomer of phycocyanin was bleached and the maximum of the band shifted from 614 nm to 620 nm. The change in absorption induced by Cu2+ was accompanied by a decreased fluorescence emission intensity and a shift of the fluorescence maximum from 649 nm to 643 nm. The difference spectra showed negative peaks at 604 nm in absorption and at 653 nm in fluorescence when the concentration of Cu2+ was low. Spectroscopic titration curves showed biphasic behavior with respect to the concentration of Cu2+. Comparison of these results with the properties of the separated alpha and beta-subunits indicates that the beta-subunit has higher affinity for Cu2+ and is bleached preferentially over the alpha-subunit. This enables one to deduce the spectra of individual subunits from the monomer without separating them. This work also indicates that the beta-subunit of phycocyanin is more labile than the alpha-subunit to denaturation with NaClO4. Partial unfolding of the protein in the presence of NaClO4 appears to decrease the protein-chromophore interaction, allowing binding of Cu2+ to the nitrogen atoms of the tetrapyrrole chromophores. This conclusion is supported by the results of a spectroscopic titration of biliverdin with Cu2+. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CHEM BIODYNAM LAB,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT CHEM,BERKELEY,CA 94720. NR 36 TC 6 Z9 7 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0006-3002 J9 BIOCHIM BIOPHYS ACTA PD JAN 22 PY 1991 VL 1056 IS 2 BP 181 EP 189 DI 10.1016/S0005-2728(05)80285-3 PG 9 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA EY944 UT WOS:A1991EY94400009 ER PT J AU LIN, WJ HARBOTTLE, G AF LIN, WJ HARBOTTLE, G TI THE HALF-LIFE AND ABUNDANCES OF THE GAMMA-RAYS OF BI-207 SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY-LETTERS LA English DT Article AB The half-life of Bi-207 has been redetermined as 32.7 +/- 0.8 years. A new set of gamma-ray abundances are also calculated. RP LIN, WJ (reprint author), BROOKHAVEN NATL LAB,DEPT CHEM,UPTON,NY 11973, USA. NR 13 TC 3 Z9 3 U1 0 U2 0 PU AKADEMIAI KIADO PI BUDAPEST PA PO BOX 245, H-1519 BUDAPEST, HUNGARY SN 0236-5731 J9 J RADIOAN NUCL CH LE JI J. Radioanal. Nucl. Chem.-Lett. PD JAN 22 PY 1991 VL 153 IS 1 BP 51 EP 55 DI 10.1007/BF02170248 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA FA258 UT WOS:A1991FA25800007 ER PT J AU ZHANG, JY HUANG, JY SHEN, YR CHEN, CT WU, BC AF ZHANG, JY HUANG, JY SHEN, YR CHEN, CT WU, BC TI PICOSECOND OPTICAL PARAMETRIC AMPLIFICATION IN LITHIUM TRIBORATE SO APPLIED PHYSICS LETTERS LA English DT Article ID XECL EXCIMER LASER; OSCILLATOR AB We report the performance of a type-I lithium triborate (LBO) optical parametric amplifier pumped by 15 ps, 355 nm laser pulses. It is seen that with proper design, LBO can be as efficient as barium borate for such an application. C1 CHINESE ACAD SCI,FUJIAN INST RES STRUCT MATTER,FUZHOU,PEOPLES R CHINA. RP ZHANG, JY (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DEPT PHYS,CTR ADV MAT,BERKELEY,CA 94720, USA. NR 12 TC 23 Z9 24 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 21 PY 1991 VL 58 IS 3 BP 213 EP 215 DI 10.1063/1.104692 PG 3 WC Physics, Applied SC Physics GA ET681 UT WOS:A1991ET68100002 ER PT J AU VAWTER, GA WENDT, JR AF VAWTER, GA WENDT, JR TI CHLORINE REACTIVE ION-BEAM ETCHING OF INSB AND INAS0.15SB0.85/INSB STRAINED-LAYER SUPERLATTICES SO APPLIED PHYSICS LETTERS LA English DT Article ID GAAS; ALGAAS; INP AB We report the first successful application of Cl2 reactive ion beam etching (RIBE) to the dry etching of bulk InSb and InAs0.15Sb0.85/InSb strained-layer superlattices (SLSs). Etching was performed in a load-locked ultrahigh vacuum chamber using an electron cyclotron resonance ion source. Etching rates for InSb and InAs0.15Sb0.85/InSb SLS with a 500 eV Cl2 beam at 0.6 mA/cm2 are 280 and 240 nm/min, respectively, compared to 310 nm/min for GaAs. The sputter yield for Cl2 RIBE in this antimonide system is double that obtained by Ar ion milling under identical conditions. RP VAWTER, GA (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 11 TC 15 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JAN 21 PY 1991 VL 58 IS 3 BP 289 EP 291 DI 10.1063/1.104664 PG 3 WC Physics, Applied SC Physics GA ET681 UT WOS:A1991ET68100028 ER PT J AU WU, XD MUENCHAUSEN, RE NOGAR, NS PIQUE, A EDWARDS, R WILKENS, B RAVI, TS HWANG, DM CHEN, CY AF WU, XD MUENCHAUSEN, RE NOGAR, NS PIQUE, A EDWARDS, R WILKENS, B RAVI, TS HWANG, DM CHEN, CY TI EPITAXIAL YTTRIA-STABILIZED ZIRCONIA ON (1102)SAPPHIRE FOR YB2CU3O7-DELTA THIN-FILMS SO APPLIED PHYSICS LETTERS LA English DT Article ID SILICON; GROWTH; DEPOSITION AB Epitaxial yttria-stabilized zirconia (YSZ) films were deposited on (1102BAR1) sapphire by pulsed laser deposition. The films are formed in a cubic phase with the a axis normal to the substrate surface. Ion beam (2.8 MeV He++) channeling measurements shows that the YSZ films are highly crystalline with a channeling minimum yield of 8%. The epitaxial relationship between the film and substrate is further confirmed by a cross-section transmission electron microscopy study. Epitaxial YBa2Cu3O7-delta thin films deposited on YSZ/sapphire have T(c) and J(c) of up to 89 K and 1 x 10(6) A/cm2 at 77 K, respectively. C1 UNIV CALIF LOS ALAMOS SCI LAB,ERDC,DIV CHEM & LASER SCI,LOS ALAMOS,NM 87545. NEOCERA INC,NEW BRUNSWICK,NJ 08901. BELLCORE,RED BANK,NJ 07701. RP WU, XD (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,ERDC,DIV MAT SCI & TECHNOL,LOS ALAMOS,NM 87545, USA. NR 17 TC 71 Z9 73 U1 0 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 JAN 21 PY 1991 VL 58 IS 3 BP 304 EP 306 DI 10.1063/1.104669 PG 3 WC Physics, Applied SC Physics GA ET681 UT WOS:A1991ET68100033 ER PT J AU PORTIS, AM COOKE, DW GRAY, ER ARENDT, PN BOHN, CL DELAYEN, JR ROCHE, CT HEIN, M KLEIN, N MULLER, G ORBACH, S PIEL, H AF PORTIS, AM COOKE, DW GRAY, ER ARENDT, PN BOHN, CL DELAYEN, JR ROCHE, CT HEIN, M KLEIN, N MULLER, G ORBACH, S PIEL, H TI POWER AND MAGNETIC FIELD-INDUCED MICROWAVE-ABSORPTION IN TL-BASED HIGH-TC SUPERCONDUCTING FILMS SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE-RESISTANCE; THIN-FILMS; YBA2CU3O7-X; GHZ AB The increase in the microwave surface resistance R(s) of high T(c) superconductors at elevated microwave power levels is reported for both oriented and unoriented T1-based films as a function of rf magnetic field at 820 MHz and 18 GHz. The application of dc magnetic fields produces qualitatively similar increases in R(s) and in the surface reactance X(s). The increase in R(s) with dc field is shown to arise from simple decoupling of grains by intergranular magnetic flux. The increase in R(s) with microwave power, on the other hand, is a consequence of hysteretic intergranular processes. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. ARGONNE NATL LAB,ARGONNE,IL 60439. BERG UNIV WUPPERTAL,WUPPERTAL,GERMANY. RP PORTIS, AM (reprint author), UNIV CALIF BERKELEY,BERKELEY,CA 94720, USA. RI Klein, Norbert/C-1473-2017 NR 16 TC 43 Z9 43 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 JAN 21 PY 1991 VL 58 IS 3 BP 307 EP 309 DI 10.1063/1.104670 PG 3 WC Physics, Applied SC Physics GA ET681 UT WOS:A1991ET68100034 ER PT J AU BELTRAN, S BAKER, JP HOOPER, HH BLANCH, HW PRAUSNITZ, JM AF BELTRAN, S BAKER, JP HOOPER, HH BLANCH, HW PRAUSNITZ, JM TI SWELLING EQUILIBRIA FOR WEAKLY IONIZABLE, TEMPERATURE-SENSITIVE HYDROGELS SO MACROMOLECULES LA English DT Article ID GELS AB Swelling equilibria in aqueous citrate-phosphate buffer solutions are reported for thermally sensitive poly(N-isopropylacrylamide) hydrogels containing weakly ionizable groups. The comonomers containing these groups were sodium acrylate and 2-(dimethylamino)ethyl methacrylate to produce gels with, respectively, acidic and basic character. Gel swelling was measured as a function of pH, ionic strength, and temperature. With increasing ionization, the temperature range over which the gel volume change is greatest becomes larger and shifts to higher temperatures. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,1 CYCLOTRON RD,BERKELEY,CA 94720. UNIV CALIF BERKELEY,DEPT CHEM ENGN,BERKELEY,CA 94720. OI Beltran, Sagrario/0000-0003-2559-3925 NR 13 TC 174 Z9 175 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JAN 21 PY 1991 VL 24 IS 2 BP 549 EP 551 DI 10.1021/ma00002a032 PG 3 WC Polymer Science SC Polymer Science GA EU814 UT WOS:A1991EU81400032 ER PT J AU BECKER, JA BERGER, A BLOMQVIST, J DECMAN, DJ ESTEP, R HENRY, E MAIER, KH MANN, LG MEYER, RA POPPELIER, NAFM ROY, N STOFF, W STRUBLE, GL WOOD, LD AF BECKER, JA BERGER, A BLOMQVIST, J DECMAN, DJ ESTEP, R HENRY, E MAIER, KH MANN, LG MEYER, RA POPPELIER, NAFM ROY, N STOFF, W STRUBLE, GL WOOD, LD TI QUADRUPOLE-MOMENTS OF LOW-ENERGY ISOMERS IN PO-210 SO NUCLEAR PHYSICS A LA English DT Article ID ELECTROMAGNETIC PROPERTIES; LEAD REGION; SPECTROSCOPY; STATES AB The quadrupole interaction frequencies of the 8+, 11-, 13- and 16+ isomers in Po-210 have been measured in a Bi single crystal by the DPAD method with the Bi-209(t, 2n) Po-210 reaction. The results for the quadrupole moments, normalized to Q(8(1)+) = -55.2 (20) fm2, are (Q(11-)) = 86 (11) fm2, (Q(13-)) = 90 (7) fm2 and (Q(16+)) = 129.7 (20) fm2. The quadrupole moment of the 0i13/2 proton orbital was deduced, and found to be surprisingly small. The results are compared with shell model calculations using the surface delta interaction as residual interaction. C1 HAHN MEITNER INST KERNFORSCH BERLIN GMBH,W-1000 BERLIN 39,GERMANY. RES INST PHYS,STOCKHOLM,SWEDEN. STATE UNIV UTRECHT,UTRECHT,NETHERLANDS. RP BECKER, JA (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 23 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 JAN 21 PY 1991 VL 522 IS 3-4 BP 483 EP 493 DI 10.1016/0375-9474(91)90077-J PG 11 WC Physics, Nuclear SC Physics GA FA006 UT WOS:A1991FA00600003 ER PT J AU SATCHLER, GR MCVOY, KW HUSSEIN, MS AF SATCHLER, GR MCVOY, KW HUSSEIN, MS TI EXPLORATORY STUDIES OF THE ELASTIC-SCATTERING OF LI-11+C-12 SO NUCLEAR PHYSICS A LA English DT Article ID REACTION CROSS-SECTIONS; HEAVY-ION COLLISIONS; INTERMEDIATE ENERGIES; UNSTABLE NUCLEUS; OPTICAL-MODEL; FOLDING MODEL; DEPENDENCE; BREAKUP; RADII; C-12 AB Calculations have been made of the elastic scattering of Li-11 + C-12 at E/A = 30 and 85 MeV as an example of the scattering to be expected for "exotic" neutron-rich light nuclei. The real optical potential was generated from a folding model using Hartree-Fock densities for Li-11. A variety of assumptions for the absorptive imaginary potential was explored, subject to the important constraint that the predicted reaction cross section remain reasonable. Contrary to some expectations, we provide evidence that these weakly bound systems do not exhibit the diffractive type of scattering that is characteristic of strong absorption. If anything their more diffuse real potentials can result in an enhancement of the refractive features. C1 UNIV WISCONSIN,DEPT PHYS,MADISON,WI 53706. UNIV SAO PAULO,INST FIS,SAO PAULO,BRAZIL. RP SATCHLER, GR (reprint author), OAK RIDGE NATL LAB,DIV PHYS,OAK RIDGE,TN 37831, USA. NR 32 TC 44 Z9 44 U1 1 U2 3 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 JAN 21 PY 1991 VL 522 IS 3-4 BP 621 EP 634 DI 10.1016/0375-9474(91)90085-K PG 14 WC Physics, Nuclear SC Physics GA FA006 UT WOS:A1991FA00600011 ER PT J AU RANDRUP, J AF RANDRUP, J TI MICROCANONICAL SAMPLING OF MOMENTA SO NUCLEAR PHYSICS A LA English DT Article ID MULTIFRAGMENTATION AB The method recently employed by Lopez and Randrup presents a simple, efficient, and exact procedure for sampling of the microcanonical momentum distribution for classical, non-relativistic many-body systems subject to energy and momentum conservation. Moreover, by straightforward generalization, the method also applies to any combination of linear, radial, and angular momentum conservation. RP RANDRUP, J (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV NUCL MED,BERKELEY,CA 94720, USA. 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 0375-9474 J9 NUCL PHYS A JI Nucl. Phys. A PD JAN 21 PY 1991 VL 522 IS 3-4 BP 651 EP 658 DI 10.1016/0375-9474(91)90088-N PG 8 WC Physics, Nuclear SC Physics GA FA006 UT WOS:A1991FA00600014 ER PT J AU LIBBY, SB ZOU, Z LAUGHLIN, RB AF LIBBY, SB ZOU, Z LAUGHLIN, RB TI NON-ABELIAN MONOPOLES IN THE 3-DIMENSIONAL CHIRAL SPIN LIQUID SO NUCLEAR PHYSICS B LA English DT Article ID RESONATING-VALENCE-BOND; GAUGE NONINVARIANCE; SUPERCONDUCTIVITY; STATE; STATISTICS AB We show by explicit numerical calculation that the charged spinless excitations of the three-dimensional chiral spin liquid state have nonzero Berry phases analogous to the 1/2 fractional statistics seen in two dimensions. These reduce, in the limit of large separation and low velocities to vector potentials of magnetic monopoles coupling to the four internal degrees of freedom of the moving particle through generators of SU(4). C1 STANFORD UNIV,DEPT APPL PHYS,STANFORD,CA 94305. RP LIBBY, SB (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,POB 808,LIVERMORE,CA 94550, USA. NR 25 TC 19 Z9 19 U1 2 U2 5 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 JAN 21 PY 1991 VL 348 IS 3 BP 693 EP 713 DI 10.1016/0550-3213(91)90210-O PG 21 WC Physics, Particles & Fields SC Physics GA ER470 UT WOS:A1991ER47000012 ER PT J AU FISCHBACH, E GREENE, GL HUGHES, RJ AF FISCHBACH, E GREENE, GL HUGHES, RJ TI NEW TEST OF QUANTUM-MECHANICS - IS PLANCK CONSTANT UNIQUE SO PHYSICAL REVIEW LETTERS LA English DT Article ID FINE-STRUCTURE CONSTANT; NEUTRON AB We discuss the possibility that different realms of physics are described by distinct quantization constants. From the consistency of existing data, we infer limits on the differences between hypothetically distinct quantization constants for different elementary particles. Since the existence of multiple Planck constants implies violations of space-time symmetries, these limits may be viewed as precise tests of fundamental conservation laws, including the conservation of linear momentum and energy. C1 NATL INST STANDARDS & TECHNOL,GAITHERSBURG,MD 20899. UNIV CALIF LOS ALAMOS SCI LAB,DIV PHYS,LOS ALAMOS,NM 87545. RP FISCHBACH, E (reprint author), PURDUE UNIV,DEPT PHYS,W LAFAYETTE,IN 47907, USA. NR 17 TC 9 Z9 9 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 JAN 21 PY 1991 VL 66 IS 3 BP 256 EP 259 DI 10.1103/PhysRevLett.66.256 PG 4 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000003 ER PT J AU BRIGHTWELL, G GREGORY, R AF BRIGHTWELL, G GREGORY, R TI STRUCTURE OF RANDOM DISCRETE SPACETIME SO PHYSICAL REVIEW LETTERS LA English DT Article AB The usual picture of spacetime consists of a continuous manifold, together with a metric of Lorentzian signature which imposes a causal structure. We consider a model in which spacetime consists of a discrete set of points taken at random from a manifold, with only the causal structure remaining. Using only this structure, we show how to construct a metric, how to define the effective dimension, and how such quantities may depend on the scale of measurement. We discuss possible desirable features of the model. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP BRIGHTWELL, G (reprint author), UNIV LONDON LONDON SCH ECON & POLIT SCI,DEPT MATH,HOUGHTON ST,LONDON WC2A 2AE,ENGLAND. NR 7 TC 54 Z9 54 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 JAN 21 PY 1991 VL 66 IS 3 BP 260 EP 263 DI 10.1103/PhysRevLett.66.260 PG 4 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000004 ER PT J AU NILSEN, J AF NILSEN, J TI NI-LIKE X-RAY LASERS RESONANTLY PHOTOPUMPED BY LY-ALPHA RADIATION SO PHYSICAL REVIEW LETTERS LA English DT Article ID CROSS-SECTIONS; PLASMAS; SPECTRA; IONS AB This Letter proposes a new class of x-ray lasers that lase on several 4d-->4p transitions ranging from 23 to 80 angstrom in Ni-like ions with atomic number Z = 72 to 90 and are resonantly photopumped by Ly-alpha radiation from corresponding H-like ions with atomic number (Z-21)/3. This scheme is unique in that it consists of a family of resonant pairs working off the ground state of the laser ion. Calculations of the gain of these laser transitions in steady-state equilibrium plasmas are presented. RP NILSEN, J (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. NR 15 TC 20 Z9 20 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 21 PY 1991 VL 66 IS 3 BP 305 EP 308 DI 10.1103/PhysRevLett.66.305 PG 4 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000015 ER PT J AU CLARKE, R DOSPASSOS, W LOWE, W RODRICKS, BG BRIZARD, C AF CLARKE, R DOSPASSOS, W LOWE, W RODRICKS, BG BRIZARD, C TI REAL-TIME X-RAY STUDIES OF STRAIN KINETICS IN INXGA1-XAS QUANTUM-WELL STRUCTURES SO PHYSICAL REVIEW LETTERS LA English DT Article ID CRITICAL LAYER THICKNESS; GAAS; HETEROSTRUCTURES; DIFFRACTION; INGAAS AB A new time-resolved x-ray method of probing the kinetics of interfacial strains in semiconductor heterostructures is presented. High-resolution synchrotron-radiation measurements of the strain relaxation during rapid thermal annealing show that the lattice dilation of an as-grown quantum well structure is relieved cooperatively by a series of sluggish discontinuous transitions. Well-defined metastable states of strain are observed between the transitions. C1 AT&T BELL LABS,MURRAY HILL,NJ 07974. ARGONNE NATL LAB,DIV ADV PHOTON SOURCE,ARGONNE,IL 60439. RP CLARKE, R (reprint author), UNIV MICHIGAN,DEPT PHYS,ANN ARBOR,MI 48109, USA. NR 15 TC 10 Z9 10 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 21 PY 1991 VL 66 IS 3 BP 317 EP 320 DI 10.1103/PhysRevLett.66.317 PG 4 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000018 ER PT J AU RICKMAN, JM PHILLPOT, SR AF RICKMAN, JM PHILLPOT, SR TI TEMPERATURE-DEPENDENCE OF THERMODYNAMIC QUANTITIES FROM SIMULATIONS AT A SINGLE TEMPERATURE SO PHYSICAL REVIEW LETTERS LA English DT Article ID MONTE-CARLO DATA; FREE-ENERGY AB A new method is developed for obtaining thermodynamic information over a wide range in parameter space from a series expansion involving the first few cumulants of a distribution function which is generated at one point in parameter space. The method is employed to obtain the temperature dependence of the Gibbs free energy, the enthalpy, and the lattice parameter of a Lennard-Jones crystal from Monte Carlo simulations. Good agreement with independent calculations is found over a temperature range of approximately 75% of the melting temperature. RP RICKMAN, JM (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60438, USA. RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 11 TC 32 Z9 32 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 21 PY 1991 VL 66 IS 3 BP 349 EP 352 DI 10.1103/PhysRevLett.66.349 PG 4 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000026 ER PT J AU HO, KM CHAN, CT SOUKOULIS, CM AF HO, KM CHAN, CT SOUKOULIS, CM TI THEORY OF PHOTON BANDS IN 3-DIMENSIONAL PERIODIC DIELECTRIC STRUCTURES - COMMENT SO PHYSICAL REVIEW LETTERS LA English DT Letter C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP HO, KM (reprint author), US DOE,AMES LAB,AMES,IA 50011, USA. RI Soukoulis, Costas/A-5295-2008 NR 10 TC 9 Z9 9 U1 0 U2 7 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 JAN 21 PY 1991 VL 66 IS 3 BP 393 EP 393 DI 10.1103/PhysRevLett.66.393 PG 1 WC Physics, Multidisciplinary SC Physics GA ET680 UT WOS:A1991ET68000037 ER PT J AU BREWER, LR AF BREWER, LR TI HIGHLY COHERENT INJECTION-LOCKED LASER DIODE-ARRAYS SO APPLIED OPTICS LA English DT Article ID LOCKING AB Two physically separated laser diode arrays were simultaneously injection-locked to the same master laser. The modulus of their mutual coherence function was measured, and the resulting value 0.96 +/- 0.06 was close to the maximum allowed value of 1. The spatial phase of the two injection-locked outputs did not vary from each other by more than 0.05 wave (lambda/20), apart from a phase difference that grew linearly with position, due to the tilt between the two interfering beams. Requirements for the coherent combination of injection-locked laser diode arrays are discussed. RP BREWER, LR (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Brewer, Laurence/G-4056-2012 NR 8 TC 9 Z9 9 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 SN 0003-6935 J9 APPL OPTICS JI Appl. Optics PD JAN 20 PY 1991 VL 30 IS 3 BP 317 EP 320 PG 4 WC Optics SC Optics GA EV207 UT WOS:A1991EV20700007 PM 20581984 ER PT J AU JUDA, M BLOCH, JJ EDWARDS, BC MCCAMMON, D SANDERS, WT SNOWDEN, SL ZHANG, J AF JUDA, M BLOCH, JJ EDWARDS, BC MCCAMMON, D SANDERS, WT SNOWDEN, SL ZHANG, J TI LIMITS ON THE DENSITY OF NEUTRAL GAS WITHIN 100 PARSECS FROM OBSERVATIONS OF THE SOFT-X-RAY BACKGROUND SO ASTROPHYSICAL JOURNAL LA English DT Article DE INTERSTELLAR, MATTER; X-RAYS, GENERAL ID LOCAL INTERSTELLAR-MEDIUM; ULTRAVIOLET OBSERVATIONS; DEUTERIUM; HYDROGEN AB We present observations in two soft X-ray bands, the Be band (0.077-0.11 1 keV) and the B' band (0.105-0.188 keV), for nine directions in the sky. The ratio of count rates in these two bands remains constant as the rates vary by a factor of 3, even though the effective interstellar absorption cross sections in the bands differ by a factor of approximately 3.5. For a model in which the bulk of the observed soft X-ray emission originates in a uniform low-density region surrounding the Sun, the constant ratio between the band rates places an upper limit on the amount of neutral material that can be homogeneously mixed with the X-ray-emitting gas. The 2-sigma upper limit on the H I column density over an average path through the local emitting region is 6.6 x 10(18) cm-2. If the average path length is approximately 100 pc, then clouds similar to the one in which the Sun is embedded (n(H) approximately 0.1 cm-3) could still have a filling factor as large as 25%. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. MAX PLANCK INST PHYS & ASTROPHYS,INST EXTRATERR PHYS,W-8046 GARCHING,GERMANY. RP JUDA, M (reprint author), UNIV WISCONSIN,DEPT DIABET RES & TRAINING,MADISON,WI 53706, USA. RI Snowden, Steven/D-5292-2012; OI Juda, Michael/0000-0002-4375-9688 NR 24 TC 38 Z9 38 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 JAN 20 PY 1991 VL 367 IS 1 BP 182 EP 185 DI 10.1086/169615 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800019 ER PT J AU HARTMANN, DH LINDER, EV BLUMENTHAL, GR AF HARTMANN, DH LINDER, EV BLUMENTHAL, GR TI FUZZY CORRELATIONS OF GAMMA-RAY BURSTS SO ASTROPHYSICAL JOURNAL LA English DT Article DE GAMMA-RAYS, BURSTS AB The origin of gamma-ray bursts is not known, both in the sense of the nature of the source emitting the radiation and literally, the position of the burst on the sky. Lacking unambiguously identified counterparts in any wave-length band studied to date, statistical approaches are required to determine the burster distance scale. Angular correlation analysis is one of the most powerful tools in this regard. However, poor detector resolution gives large localization errors, effectively beam smearing the positions. We investigate the resulting fuzzy angular correlation function and discuss the generic isotropization that smearing induces on any intrinsic clustering. In particular, we investigate the extent to which gamma-ray burst observations by the BATSE detector aboard the Gamma-Ray Observatory might recover an intrinsic source correlation. C1 UNIV CALIF SANTA CRUZ,LICK OBSERV,BOARD STUDIES ASTRON & ASTROPHYS,SANTA CRUZ,CA 95064. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,INST GEOPHYS & PLANETARY PHYS,LIVERMORE,CA 94550. STANFORD UNIV,CTR SPACE SCI & ASTROPHYS,STANFORD,CA 94305. UNIV ARIZONA,STEWARD OBSERV,TUCSON,AZ 85724. NR 16 TC 12 Z9 12 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 JAN 20 PY 1991 VL 367 IS 1 BP 186 EP 190 DI 10.1086/169616 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800020 ER PT J AU SAIZAR, P STARRFIELD, S FERLAND, GJ WAGNER, RM TRURAN, JW KENYON, SJ SPARKS, WM WILLIAMS, RE STRYKER, LL AF SAIZAR, P STARRFIELD, S FERLAND, GJ WAGNER, RM TRURAN, JW KENYON, SJ SPARKS, WM WILLIAMS, RE STRYKER, LL TI PW VULPECULAE - A NOVA WITH NEARLY SOLAR ABUNDANCES SO ASTROPHYSICAL JOURNAL LA English DT Article DE STARS, ABUNDANCES; STARS, INDIVIDUAL (PW VUL); STARS, NOVAE; ULTRAVIOLET, SPECTRA ID SPECTROSCOPIC OBSERVATIONS; CLASSICAL NOVAE; CYGNI 1975; LINES; EMISSION; NEBULAE; EJECTA; NEON AB Optical spectrophotometry of PW Vulpeculae (Nova Vul 1984 #1) is combined with ultraviolet data to estimate electron temperatures, densities, and abundances in the ejecta of this slow classical nova. We also discuss the reddening, the distance, and the evolution of the ultraviolet spectrum. Abundances are nearly solar, with the exception of nitrogen, which is substantially higher. Although neon has been reported to be enhanced in several novae, it does not seem to be the case for PW Vul. We present photoionization model calculations of the ejecta that give a reasonable match of the observed emission spectrum. A strong featureless continuum shows that very hot, presumably shock-heated, gas plays a major role in determining the energetics of this nova. Emission from this hot gas is responsible for the ionization of the nebular gas. A calculation of the masses of both the hot coronal gas and the cooler nebular gas shows that the former may account for most of the mass of the ejecta. C1 ARIZONA STATE UNIV,DEPT PHYS & ASTRON,TEMPE,AZ 85287. UNIV ILLINOIS,DEPT ASTRON,URBANA,IL 61801. CTR ASTROPHYS,SMITHSONIAN ASTROPHYS LAB,CAMBRIDGE,MA 02138. UNIV CALIF LOS ALAMOS SCI LAB,DIV APPL THEORET PHYS,LOS ALAMOS,NM 87545. NATL OPT ASTRON OBSERV,CERRO TOLOLO INTERAMER OBSERV,LA SERENA,CHILE. LOWELL OBSERV,FLAGSTAFF,AZ 86001. RP SAIZAR, P (reprint author), OHIO STATE UNIV,DEPT ASTRON,COLUMBUS,OH 43210, USA. OI Kenyon, Scott/0000-0003-0214-609X; Ferland, Gary/0000-0003-4503-6333 NR 32 TC 38 Z9 38 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 JAN 20 PY 1991 VL 367 IS 1 BP 310 EP 320 DI 10.1086/169630 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA ER078 UT WOS:A1991ER07800034 ER PT J AU PENNER, JE ATHERTON, CS DIGNON, J GHAN, SJ WALTON, JJ HAMEED, S AF PENNER, JE ATHERTON, CS DIGNON, J GHAN, SJ WALTON, JJ HAMEED, S TI TROPOSPHERIC NITROGEN - A 3-DIMENSIONAL STUDY OF SOURCES, DISTRIBUTIONS, AND DEPOSITION SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; NITRIC-OXIDE MEASUREMENTS; BOUNDARY-LAYER; PACIFIC-OCEAN; UNPOLLUTED TROPOSPHERE; NITRATE CONCENTRATIONS; EQUATORIAL PACIFIC; CLOUD TRANSPORT; ACID VAPOR; PRECIPITATION AB We simulate the global cycle of reactive nitrogen in a three-dimensional model of chemistry, transport, and deposition. Our model is based on the Lagrangian tracer model described by Walton et al. [1988] and uses winds and precipitation fields calculated by the Livermore version of the NCAR Community Climate Model. The model includes the basic chemical reactions of NO, NO2, and HNO3. For this study, we use prescribed OH and O3 concentrations and calculate the concentrations of NO, NO2, and HNO3 for a perpetual January and a perpetual July. The sources of reactive nitrogen due to fossil-fuel combustion (22 Mt N/yr), lightning discharges (3 Mt N/yr), soil microbial activity (10 Mt N/yr), biomass burning (6 Mt N/yr), and the oxidation of N2O in the stratosphere (1 Mt N/yr) are included. Model-predicted concentrations of NO, NO2, and HNO3 are compared to available measurements. In general, we find reasonable agreement between model predictions and measurements except for concentrations of HNO3 in the remote Pacific. At these latter locations, we require a larger source of reactive nitrogen to fit the observations. This may be supplied by lightning discharges, although increasing this source degrades our agreement with measured HNO3 abundances in the free troposphere. Alternatively, a local marine source could contribute to the measured abundances. Predictions for nitrate deposition by precipitation are within a factor of 2 of measured deposition rates in the northern hemisphere in the summer and in both seasons at remote locations. The model underpredicts nitrate deposition in winter in Europe, due primarily to the excessively strong winds generated by the general circulation model. Model simulations for NO(x) and HNO3 surface mixing ratios from calculations including only the fossil-fuel source, only natural sources, and all sources acting together, are compared. Anthropogenic sources have substantially increased the concentrations of NO(x) and HNO3 throughout all continents during both January and July. Fossil-fuel sources are responsible for most of this increase in the northern hemisphere, while both biomass burning and fossil-fuel combustion contribute in the southern hemisphere. C1 SUNY STONY BROOK, DEPT MECH ENGN, STONY BROOK, NY 11794 USA. SUNY STONY BROOK, PLANETARY ATMOSPHERES RES LAB, STONY BROOK, NY 11794 USA. RP PENNER, JE (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB, DIV ATMOSPHER & GEOPHYS RES, POB 808, LIVERMORE, CA 94550 USA. RI Penner, Joyce/J-1719-2012; Ghan, Steven/H-4301-2011 OI Ghan, Steven/0000-0001-8355-8699 NR 95 TC 149 Z9 153 U1 1 U2 14 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1991 VL 96 IS D1 BP 959 EP 990 DI 10.1029/90JD02228 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EV403 UT WOS:A1991EV40300007 ER PT J AU KLEINMAN, LI DAUM, PH AF KLEINMAN, LI DAUM, PH TI VERTICAL-DISTRIBUTION OF AEROSOL-PARTICLES, WATER-VAPOR, AND INSOLUBLE TRACE GASES IN CONVECTIVELY MIXED AIR SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RESPONSE CHARACTERISTICS; ATMOSPHERIC POLLUTANTS; (NH4)2SO4 PARTICLES; SIZE DISTRIBUTIONS; CLOUD TRANSPORT; WET REMOVAL; TROPOSPHERE; OZONE; REDISTRIBUTION; PROFILES AB Vertical distributions of submicrometer size aerosol particles, water vapor, and the insoluble gases (O3, CO, and NO(y) were determined from measurements made during 12 aircraft flights conducted in June 1987 near Columbus, Ohio. Measurements extended from the surface to 290 mbar (approximately 9.5 km) and were made primarily in the vicinity of convective storms. The mixing ratio of aerosol particles decreased strongly with altitude, from an average value of 1800 scm-3 (SCM, standard centimeter) (at 20-degrees-C, 1 atm) near the surface to a value in the upper troposphere (30 scm-3, above 300 mbar) that was, on average, less than 2% of the near-surface mixing ratio. This decrease was similar to that exhibited by water vapor. CO and NO(y), in contrast, were more uniformly distributed. Average upper tropospheric mixing ratios were 128 and 0.8 ppb, 51 and 35%, respectively, of boundary layer values. Compact plumelike features were observed at high altitude in which concentrations of boundary layer constituents increased by 50% or more over a distance of several kilometers. These features are attributed to boundary layer air that had been transported upward in convective storms. Such boundary layer air encountered aloft could contain higher mixing ratios of water vapor and aerosol particles than found in adjacent regions, but on an absolute basis these soluble substances were always severely depleted relative to the insoluble gases, CO and NO(y). We ascribe the qualitative difference between the vertical distributions of soluble and insoluble substances as being due to in-cloud processes occurring during upward transport. The upward transport of soluble material is limited by dissolution in cloud water and subsequent conversion of cloud water to downward moving precipitation, whereas insoluble pollutants are not affected by this process. RP KLEINMAN, LI (reprint author), BROOKHAVEN NATL LAB, DEPT APPL SCI, DIV ENVIRONM CHEM, UPTON, NY 11973 USA. NR 35 TC 31 Z9 36 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 1991 VL 96 IS D1 BP 991 EP 1005 DI 10.1029/90JD02117 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA EV403 UT WOS:A1991EV40300008 ER PT J AU TORNEY, DC AF TORNEY, DC TI MAPPING USING UNIQUE SEQUENCES SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article ID PHYSICAL MAP; STRATEGY; GENOME RP TORNEY, DC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,T-10,LOS ALAMOS,NM 87545, USA. NR 11 TC 21 Z9 21 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 JAN 20 PY 1991 VL 217 IS 2 BP 259 EP 264 DI 10.1016/0022-2836(91)90540-M PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA EW298 UT WOS:A1991EW29800008 PM 1992162 ER PT J AU LUCAS, JP STEPHENS, JJ GREULICH, FA AF LUCAS, JP STEPHENS, JJ GREULICH, FA TI THE EFFECT OF REINFORCEMENT STABILITY ON COMPOSITION REDISTRIBUTION IN CAST-ALUMINUM METAL MATRIX COMPOSITES SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article ID DISLOCATION GENERATION; PARTICULATE COMPOSITES; SILICON-CARBIDE AB A detailed microstructural characterization was performed on cast Al-7Si particulate-reinforced metal matrix composites (where the composition is in approximate weight per cent) which included extensive examination of particulate-matrix interfacial precipitation reactions. Essentially no reaction products were observed at the interface of SiC particulates. In sharp contrast, however, an extensive reaction product zone was observed at the interface and at near-interface regions of B4C reinforcement. The type of reinforcement was shown to have a profound effect on the interfacial precipitation, the elemental composition distribution and the as-cast and solution-treated-and-aged microstructures of the matrix alloy. The stability of SiC particulates in the A356 matrix alloy (Al-7Si-0.35Mg-0.2Ti) was substantially greater in comparison with highly reactive B4C particulates. Electron microprobe, scanning electron microscopy and scanning transmission electron microscopy were used to identify and analyze phases associated with the bulk matrix microstructure and the particulate-matrix interfacial reaction zones. The extensive matrix-reinforcement reactions caused selective partitioning of matrix alloying elements, thereby modifying the matrix microstructure in the composites by compositional redistribution in the matrix. B4C significantly modified the matrix microstructure of the composite, whereas the matrix containing SiC particulates remained essentially unchanged. C1 SANDIA NATL LABS,DIV PHYS MET,ALBUQUERQUE,NM 87185. SANDIA NATL LABS,DIV MAT COMPATIBIL & RELIABIL,ALBUQUERQUE,NM 87185. RP LUCAS, JP (reprint author), SANDIA NATL LABS,DIV JOINING & PHYS MET,POB 969,LIVERMORE,CA 94551, USA. NR 15 TC 26 Z9 27 U1 1 U2 9 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 JAN 20 PY 1991 VL 131 IS 2 BP 221 EP 230 DI 10.1016/0921-5093(91)90398-7 PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA EV095 UT WOS:A1991EV09500008 ER PT J AU CLOSE, F AF CLOSE, F TI WHATEVER HAPPENED TO COLD FUSION - COLD FUSION .1. THE DISCOVERY THAT NEVER WAS SO NEW SCIENTIST LA English DT Article C1 OAK RIDGE NATL LAB,OAK RIDGE,TN. RP CLOSE, F (reprint author), RUTHERFORD APPLETON LAB,DIDCOT OX11 0QX,OXON,ENGLAND. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NEW SCIENTIST PUBL EXPEDITING INC PI ELMONT PA 200 MEACHAM AVE, ELMONT, NY 11003 SN 0262-4079 J9 NEW SCI JI New Sci. PD JAN 19 PY 1991 VL 129 IS 1752 BP 46 EP 50 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA EU426 UT WOS:A1991EU42600034 ER PT J AU CHAN, CK CHEN, LXQ DIMAGNO, TJ HANSON, DK NANCE, SL SCHIFFER, M NORRIS, JR FLEMING, GR AF CHAN, CK CHEN, LXQ DIMAGNO, TJ HANSON, DK NANCE, SL SCHIFFER, M NORRIS, JR FLEMING, GR TI INITIAL ELECTRON-TRANSFER IN PHOTOSYNTHETIC REACTION CENTERS OF RHODOBACTER-CAPSULATUS MUTANTS SO CHEMICAL PHYSICS LETTERS LA English DT Article ID RHODOPSEUDOMONAS-VIRIDIS; CHARGE SEPARATION; SPHAEROIDES R-26; MUTAGENESIS; SITE AB The stimulated emission decay time constants were measured for a series of Rhodobacter capsulatus reaction centers with site-specific mutations at the symmetry related locations M208 and L181. We report the first mutant (Phe(L181) --> Tyr) that exhibits an initial electron transfer rate faster than the native organism at 295 K, and determine that the tyrosine at position M208 cannot be fully responsible for the unidirectionality of electron transfer. C1 UNIV CHICAGO,JAMES FRANCK INST,CHICAGO,IL 60637. ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. RP CHAN, CK (reprint author), UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637, USA. NR 23 TC 86 Z9 87 U1 1 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 JAN 18 PY 1991 VL 176 IS 3-4 BP 366 EP 372 DI 10.1016/0009-2614(91)90045-B PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EY532 UT WOS:A1991EY53200020 ER PT J AU PENG, TH BROECKER, WS AF PENG, TH BROECKER, WS TI DYNAMIC LIMITATIONS ON THE ANTARCTIC IRON FERTILIZATION STRATEGY SO NATURE LA English DT Article ID RADIOCARBON; OCEAN AB MARTIN et al. have proposed an ingenious means by which the rise in atmospheric CO2 content generated by the burning of fossil fuels and deforesation might be partially compensated. The idea is that plant production in the nutrient-rich surface waters of the Antarctic could be stimulated by the addition of dissolved iron, thereby reducing the CO2 partial pressure in these waters and allowing CO2 to flow from the atmosphere into the Antarctic Ocean. We have used a box model calibrated with transient tracer data to examine the dynamical aspects of this proposal, and conclude that after 100 years of totally successful fertilization the CO2 content of the atmosphere would be lowered by only 10 +/- 5% below what it would have been in the absence of fertilization. So if after 100 years the CO2 content of the atmosphere were 500 mu-atm without fertilization, it would be between 425 and 475 mu-atm with full fertilization. In other words, if our model calibration is correct, even if iron fertilization worked perfectly it would not significantly reduce the atmospheric CO2 content. C1 COLUMBIA UNIV,LAMONT DOHERTY GEOL OBSERV,PALISADES,NY 10964. RP PENG, TH (reprint author), OAK RIDGE NATL LAB,DIV ENVIRONM SCI,OAK RIDGE,TN 37831, USA. NR 14 TC 65 Z9 68 U1 1 U2 15 PU MACMILLAN MAGAZINES LTD PI LONDON PA 4 LITTLE ESSEX STREET, LONDON, ENGLAND WC2R 3LF SN 0028-0836 J9 NATURE JI Nature PD JAN 17 PY 1991 VL 349 IS 6306 BP 227 EP 229 DI 10.1038/349227a0 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA ET519 UT WOS:A1991ET51900050 ER PT J AU SPENCE, JR VARY, JP AF SPENCE, JR VARY, JP TI ELECTRON POSITRON SCATTERING RESONANCES FROM RELATIVISTIC 2-BODY WAVE-EQUATIONS SO PHYSICS LETTERS B LA English DT Article ID BHABHA SCATTERING; PEAK STRUCTURE; CONFINING POTENTIALS; COLLISION SYSTEMS; TH COLLISIONS; MEV ENERGIES; 1.8 MEV/C2; SEARCH; EXCHANGE; SPECTRA AB The K-matrix for electron-positron scattering is evaluated in the 0+ channel for each of three relativistic wave equations derived from QED. When all the transverse single-photon-exchange contributions are treated we obtain zero width resonances or continuum bound states at mass values of 1.351, 1.498, 1.659, 1.830, 2.009, and 2.195 MeV. We assume that neglected processes are not crucial to the complete problem and therefore we compare these results with electron-positron coincidence peaks found in heavy ion experiments performed at GSI. We suggest additional types of experiments to search for these resonances. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. RP SPENCE, JR (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 45 TC 45 Z9 45 U1 0 U2 3 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 JAN 17 PY 1991 VL 254 IS 1-2 BP 1 EP 6 DI 10.1016/0370-2693(91)90384-3 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX365 UT WOS:A1991EX36500001 ER PT J AU HAYES, AC AF HAYES, AC TI THE RELATION BETWEEN DI-NEUTRON CLUSTER MODEL AND SHELL-MODEL CONFIGURATIONS IN LI-11 SO PHYSICS LETTERS B LA English DT Article ID CROSS-SECTIONS; NUCLEI AB It is shown that the (0 + 2) h-omega shell model wave function for the Li-11-g.s. has a dominant L = 0 di-neutron cluster structure, so that the large neutron radius predicted in the two models has similar origins. However, a realistic description of the soft El resonance requires a cluster basis which includes coupling of the di-neutron to several excited states of the Li-9 core, in which case the cluster predictions for the El strengths are considerably less enhanced. RP HAYES, AC (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. NR 15 TC 27 Z9 27 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD JAN 17 PY 1991 VL 254 IS 1-2 BP 15 EP 19 DI 10.1016/0370-2693(91)90387-6 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX365 UT WOS:A1991EX36500004 ER PT J AU ROWLEY, N SATCHLER, GR STELSON, PH AF ROWLEY, N SATCHLER, GR STELSON, PH TI ON THE DISTRIBUTION OF BARRIERS INTERPRETATION OF HEAVY-ION FUSION SO PHYSICS LETTERS B LA English DT Article ID SUBBARRIER FUSION; PENETRATION; SYSTEMS; MODEL AB The significance of the interpretation of heavy-ion fusion cross sections in terms of a distribution of potential barriers is discussed. The smoothing due to the quantal barrier penetration is shown to replace a set of discrete barriers by an effective continuous distribution. It is shown how this smoothed distribution may be obtained rather directly from the measured cross sections at near- and sub-barrier energies. C1 OAK RIDGE NATL LAB,OAK RIDGE,TN 37831. RP ROWLEY, N (reprint author), SERC,DARESBURY LAB,WARRINGTON WA4 4AD,CHESHIRE,ENGLAND. NR 21 TC 373 Z9 378 U1 2 U2 5 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 JAN 17 PY 1991 VL 254 IS 1-2 BP 25 EP 29 DI 10.1016/0370-2693(91)90389-8 PG 5 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX365 UT WOS:A1991EX36500006 ER PT J AU GOLDEN, M HILL, B AF GOLDEN, M HILL, B TI HEAVY MESON DECAY CONSTANTS - 1/M CORRECTIONS SO PHYSICS LETTERS B LA English DT Article ID GAUGE-INVARIANT OPERATORS; RENORMALIZATION; LIGHT; QUARK AB The coefficients of the 1/m-suppressed dimension-five operators in the static effective field theory lagrangian have been calculated to one loop order. In this paper we calculate to order alpha-s the coefficients of the 1/m-suppressed operators in the expansion of the vector and axial vector currents containing one light and one heavy quark field. The matrix element of the time component of the axial vector current determines the decay constants of pseudoscalar heavy-light mesons. C1 FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP GOLDEN, M (reprint author), BOSTON UNIV,DEPT PHYS,590 COMMONWEALTH AVE,BOSTON,MA 02215, USA. NR 21 TC 17 Z9 17 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 JAN 17 PY 1991 VL 254 IS 1-2 BP 225 EP 230 DI 10.1016/0370-2693(91)90425-P PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX365 UT WOS:A1991EX36500042 ER PT J AU LIPKIN, HJ AF LIPKIN, HJ TI INTERFERENCE EFFECTS IN K-ETA AND K-ETA' DECAY MODES OF HEAVY MESONS - CLUES TO UNDERSTANDING WEAK TRANSITIONS AND CP VIOLATION SO PHYSICS LETTERS B LA English DT Article AB Interference between amplitudes producing-eta and eta'-mesons via their strange and nonstrange components give relative suppression factors of an order of magnitude in certain diagrams and can be used to identify penguin contributions to B --> K-eta and B --> K eta'-decays as well as annihilation diagram contributions to corresponding D decays. Similar suppression factors also arise in D(O) --> pi-0-eta and D(O) --> pi-O-eta'-decays and in charmonium decays to K + K- eta and K + K- eta'. C1 TEL AVIV UNIV,RAYMOND & BEVERLY SACKLER FAC EXACT SCI,SCH PHYS & ASTRON,IL-69978 TEL AVIV,ISRAEL. ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV PHYS,ARGONNE,IL 60439. RP LIPKIN, HJ (reprint author), WEIZMANN INST SCI,DEPT NUCL PHYS,IL-76100 REHOVOT,ISRAEL. NR 5 TC 86 Z9 86 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 JAN 17 PY 1991 VL 254 IS 1-2 BP 247 EP 252 DI 10.1016/0370-2693(91)90429-T PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA EX365 UT WOS:A1991EX36500046 ER PT J AU CHATFIELD, DC FRIEDMAN, RS TRUHLAR, DG GARRETT, BC SCHWENKE, DW AF CHATFIELD, DC FRIEDMAN, RS TRUHLAR, DG GARRETT, BC SCHWENKE, DW TI GLOBAL CONTROL OF SUPRATHRESHOLD REACTIVITY BY QUANTIZED TRANSITION-STATES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MECHANICAL REACTION PROBABILITIES; POTENTIAL-ENERGY SURFACE; THERMAL RATE CONSTANTS; H + H2; CHEMICAL-REACTIONS; TUNNELING CALCULATIONS; COLLINEAR REACTIONS; HYDROGEN MOLECULES; ADIABATIC THEORY; PHASE-SPACE AB We present evidence that the accurate quantum mechanical probability of the reaction of H with H-2 is globally controlled by quantized transition states up to very high energies. The quantized transition states produce steplike features in the cumulative reaction probability curves that are analyzed up to energies of 1.6 eV; the analysis clearly associates these steps (or ''thresholds'') with quantized dynamical bottlenecks that control the passage of reactive flux to products. We have assigned bend and stretch quantum numbers to the modes orthogonal to the reaction coordinate for all these transition states on the basis of threshold energies of semiclassical vibrationally adiabatic potential energy curves and vibrationally specific cumulative reaction probability densities. C1 UNIV MINNESOTA, DEPT CHEM, MINNEAPOLIS, MN 55455 USA. UNIV MINNESOTA, INST SUPERCOMP, MINNEAPOLIS, MN 55455 USA. PACIFIC NW LAB, MOLEC SCI RES CTR, RICHLAND, WA 99352 USA. NASA, AMES RES CTR, MOFFETT FIELD, CA 94035 USA. RI Garrett, Bruce/F-8516-2011; schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Truhlar, Donald/0000-0002-7742-7294 NR 98 TC 97 Z9 98 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD JAN 16 PY 1991 VL 113 IS 2 BP 486 EP 494 DI 10.1021/ja00002a016 PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA ET682 UT WOS:A1991ET68200016 ER PT J AU QIN, XZ TRIFUNAC, AD EATON, PE XIONG, Y AF QIN, XZ TRIFUNAC, AD EATON, PE XIONG, Y TI CUBANE RADICAL CATION IN LIQUID HYDROCARBONS - TIME-RESOLVED FLUORESCENCE DETECTED MAGNETIC-RESONANCE STUDY SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID PULSE-RADIOLYSIS; MEDIUM RINGS; SPECTROSCOPY; MATRICES; SPECTRA C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. UNIV CHICAGO,DEPT CHEM,CHICAGO,IL 60637. NR 21 TC 19 Z9 19 U1 0 U2 4 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 JAN 16 PY 1991 VL 113 IS 2 BP 669 EP 670 DI 10.1021/ja00002a042 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA ET682 UT WOS:A1991ET68200042 ER PT J AU GAINES, GL ONEIL, MP SVEC, WA NIEMCZYK, MP WASIELEWSKI, MR AF GAINES, GL ONEIL, MP SVEC, WA NIEMCZYK, MP WASIELEWSKI, MR TI PHOTOINDUCED ELECTRON-TRANSFER IN THE SOLID-STATE - RATE VS FREE-ENERGY DEPENDENCE IN FIXED-DISTANCE PORPHYRIN ACCEPTOR MOLECULES SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Note ID BIOLOGICAL MOLECULES; SOLVATION DYNAMICS; SOLVENT DEPENDENCE C1 ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439. ARGONNE NATL LAB,DIV BIOL & MED RES,ARGONNE,IL 60439. NR 32 TC 238 Z9 238 U1 1 U2 8 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 JAN 16 PY 1991 VL 113 IS 2 BP 719 EP 721 DI 10.1021/ja00002a076 PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA ET682 UT WOS:A1991ET68200076 ER PT J AU GEISER, U KINI, AM WANG, HH BENO, MA WILLIAMS, JM AF GEISER, U KINI, AM WANG, HH BENO, MA WILLIAMS, JM TI STRUCTURE AT 20-K OF THE ORGANIC SUPERCONDUCTOR KAPPA-DI[3,4-3',4'-BIS(ETHYLENEDITHIO)-2,2',5,5'-TETRATHIAFULVALENIUM] BROMO(DICYANAMIDO)CUPRATE(I), KAPPA-(BEDT-TTF)2CU[N(CN)2]BR SO ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS LA English DT Note AB kappa-Di[3,4;3',4'-bis(ethylenedithio)-2,2',5,5'-tetrathiafulvalenium] bromo(dicyanamido)-cuprate(I) (2/1), C22H16BrCuN3S16, M(r) = 978.8, orthorhombic, Pnma, a = 12.871 (5), b = 29.548 (9), c = 8.466 (6) angstrom, V = 3220 (3) angstrom3, Z = 4, D(x) = 2.019 Mg m-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 2.93 mm-1, F(000) = 1956, T = 20 (1) K, final R = 0.049 for 2400 independent observed reflections with F(o) > 3-sigma(F(o)). The structure contains molecular dimers of partially charged BEDT-TTF dagger radical cations. The dimers are arranged orthogonal to neighboring dimers and form conducting layers, separated by anion layers consisting of parallel, infinite zigzag ...dicyanamido-Cu(Br)-dicyanamido...chains. C1 ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439. RP GEISER, U (reprint author), ARGONNE NATL LAB,DIV CHEM,ARGONNE,IL 60439, USA. RI Kini, Aravinda/F-4467-2012 NR 5 TC 58 Z9 58 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-2701 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Cryst. Struct. Commun. PD JAN 15 PY 1991 VL 47 BP 190 EP 192 DI 10.1107/S0108270190007843 PN 1 PG 3 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA EW121 UT WOS:A1991EW12100071 ER PT J AU BISHOP, AR GUINEA, F LOMDAHL, PS LOUIS, E VERGES, JA AF BISHOP, AR GUINEA, F LOMDAHL, PS LOUIS, E VERGES, JA TI HOLES AND MAGNETIC TEXTURES IN THE 2-DIMENSIONAL HUBBARD-MODEL SO EUROPHYSICS LETTERS LA English DT Article ID SUPERCONDUCTIVITY; SYMMETRY; STATE; LIMIT; FLUX AB The Hubbard model in a two-dimensional square lattice is studied within the unrestricted Hartree-Fock approximation. A wide variety of solutions are found, as a function of filling and value of the Coulomb repulsion. Their properties range from those of magnetic polarons to a behavior similar to electrons in an external magnetic field (flux phases). The main features of the vortex solution are studied. It is shown that its energy increases logarithmically with system size, and that it becomes more stable for high values of the Coulomb repulsion and doping levels. Also, multivortex configurations are shown to exist. The implications of our results in the qualitative behavior of the Hubbard model as function of doping and strength of the interaction are discussed. C1 UNIV AUTONOMA MADRID,CSIC,INST CIENCIA MAT,E-28049 MADRID,SPAIN. UNIV ALICANTE,FAC CIENCIAS,E-03060 ALICANTE,SPAIN. RP BISHOP, AR (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET,LOS ALAMOS,NM 87545, USA. RI Verges, Jose/E-3265-2010; Guinea, Francisco/A-7122-2008 OI Guinea, Francisco/0000-0001-5915-5427 NR 21 TC 36 Z9 36 U1 0 U2 2 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 JAN 15 PY 1991 VL 14 IS 2 BP 157 EP 163 DI 10.1209/0295-5075/14/2/011 PG 7 WC Physics, Multidisciplinary SC Physics GA EU353 UT WOS:A1991EU35300011 ER PT J AU KIJIMA, N GRONSKY, R ENDO, H OGURI, Y MCKERNAN, SK ZETTL, A AF KIJIMA, N GRONSKY, R ENDO, H OGURI, Y MCKERNAN, SK ZETTL, A TI SUPERCONDUCTIVITY AND CHEMICAL-COMPOSITION OF THE HIGH-TC PHASE (TC - 111K) IN THE SB-PB-BI-SR-CA-CU-O SYSTEM SO JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS LA English DT Article DE SUPERCONDUCTOR; SB-PB-BI-SR-CA-CU-O SYSTEM; CHEMICAL COMPOSITION; ENERGY DISPERSIVE X-RAY SPECTROSCOPY; ELECTRICAL RESISTIVITY; MAGNETIC SUSCEPTIBILITY; X-RAY POWDER DIFFRACTION AB A superconducting phase with a critical temperature of 111 K in the Sb-Pb-Bi-Sr-Ca-Cu-O system has been synthesized by means of a long firing period. Its crystal structure is similar to the high-T(c) phase (107 K) in the Pb-Bi-Sr-Ca-Cu-O system, and its average chemical composition is 4.3%, 2.6%, 19.2%, 21.4%, 15.8% and 36.9% for Sb, Pb, Bi, Sr, Ca and Cu, respectively. The summation of the Sb concentration and the Ca concentration is approximately the same for all the samples of this phase, implying that Sb substitutes for Ca, and oxygen atoms are introduced to compensate the oxygen deficiency in the central Cu-O layer sandwiched by the two Ca layers in the crystal structure of the high-T(c) phase. C1 MITSUBISHI KASEI CORP,RES CTR,MIDORI KU,YOKOHAMA 227,JAPAN. UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720. RP KIJIMA, N (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,NATL CTR ELECTRON MICROSCOPY,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. RI Zettl, Alex/O-4925-2016 OI Zettl, Alex/0000-0001-6330-136X NR 7 TC 4 Z9 4 U1 0 U2 3 PU JAPAN J APPLIED PHYSICS PI MINATO-KU TOKYO PA DAINI TOYOKAIJI BLDG 24-8 SHINBASHI 4-CHOME, MINATO-KU TOKYO 105, JAPAN SN 0021-4922 J9 JPN J APPL PHYS 2 JI Jpn. J. Appl. Phys. Part 2 - Lett. PD JAN 15 PY 1991 VL 30 IS 1B BP L99 EP L102 DI 10.1143/JJAP.30.L99 PG 4 WC Physics, Applied SC Physics GA EV330 UT WOS:A1991EV33000009 ER PT J AU WATROUS, JJ MOSHER, D NERI, JM OTTINGER, PF OLSON, CL CROW, JT PETERSON, RR AF WATROUS, JJ MOSHER, D NERI, JM OTTINGER, PF OLSON, CL CROW, JT PETERSON, RR TI WIRE-GUIDED TRANSPORT OF INTENSE ION-BEAMS SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID Z-DISCHARGE PLASMA; CHANNELS; PROPAGATION; DESIGN; DIODE AB Light ion inertial confinement fusion requires beam transport over distances of a few meters for isolation of the diode hardware from the target explosion and for power compression by time-of-flight bunching. This paper evaluates a wire-guided transport system that uses the azimuthal magnetic field, produced by a current driven through a thin wire, to radially confine the ion beam. Ion orbits are studied to determine the injection efficiency (i.e., the fraction of the beam which is transported) under various conditions. Some ions hit the wire because of too small angular momentum at injection; others hit the wire or are lost to large radius during transport because of chaotic orbit behavior induced by a small number of return-current wires close to the beam envelope. For a multimodular scheme (10-30 beams), individual transport system are packed around the target at some standoff distance. The fraction of the beam which is lost in this field-free standoff region is also evaluated under various conditions. The standoff efficiency is then combined with the injection efficiency to give the dependence of the total transport efficiency, eta-t, on diode, focusing, transport, and standoff parameters. It is found that eta-t can be as large as about 60% for parameter values which appear to be achievable. C1 SANDIA NATL LABS,ALBUQUERQUE,NM 87185. RP WATROUS, JJ (reprint author), USN,RES LAB,DIV PLASMA PHYS,WASHINGTON,DC 20375, USA. NR 30 TC 14 Z9 14 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JAN 15 PY 1991 VL 69 IS 2 BP 639 EP 655 DI 10.1063/1.347344 PG 17 WC Physics, Applied SC Physics GA EU225 UT WOS:A1991EU22500014 ER PT J AU ASHLEY, JC AF ASHLEY, JC TI ENERGY-LOSS PROBABILITIES FOR ELECTRONS, POSITRONS, AND PROTONS IN CONDENSED MATTER SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MONTE-CARLO SIMULATION; MEAN FREE PATHS; INELASTIC-COLLISIONS; SCATTERING; CARBON; FILMS; MODEL AB An "optical-data" model for describing the dielectric response function of a medium was introduced earlier to predict energy-loss rate and inelastic mean free path for low-energy ( < 10-keV) electrons and positrons. The model is used here to calculate energy-loss probabilities for electrons, positrons, and protons for use in Monte Carlo calculations or other theoretical simulations. Results for the cumulative interaction probabilities are illustrated using optical data for carbon. RP ASHLEY, JC (reprint author), OAK RIDGE NATL LAB, DIV HLTH & SAFETY RES, OAK RIDGE, TN 37831 USA. NR 22 TC 47 Z9 47 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JAN 15 PY 1991 VL 69 IS 2 BP 674 EP 678 DI 10.1063/1.347348 PG 5 WC Physics, Applied SC Physics GA EU225 UT WOS:A1991EU22500018 ER PT J AU MOOG, ER ZAK, J BADER, SD AF MOOG, ER ZAK, J BADER, SD TI KERR EFFECT FROM PT/CO SUPERLATTICES AND THE ROLE OF THE MAGNETOOPTIC ACTIVITY OF PT SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CO/PT-LAYERED STRUCTURES; ANISOTROPY; NIUSN AB The magneto-optic response of Pt/Co superlattices is simulated to gain insight into the recent experimental findings of favorable information-storage characteristics. Major trends are reproduced qualitatively, and the calculations indicate that the Pt contributes significantly to the short-wavelength polar Kerr signal (at 4 eV). The influences of the wavelength, angle of incidence, component thicknesses, overcoat, and substrate on the rotation, ellipticity, and reflectivity are evaluated. C1 TECHNION ISRAEL INST TECHNOL,DEPT PHYS,HAIFA,ISRAEL. RP MOOG, ER (reprint author), ARGONNE NATL LAB,ARGONNE,IL 60439, USA. RI Bader, Samuel/A-2995-2013 NR 26 TC 42 Z9 42 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JAN 15 PY 1991 VL 69 IS 2 BP 880 EP 885 DI 10.1063/1.347327 PG 6 WC Physics, Applied SC Physics GA EU225 UT WOS:A1991EU22500054 ER PT J AU RAMAKRISHNAN, V GERCHMAN, SE AF RAMAKRISHNAN, V GERCHMAN, SE TI CLONING, SEQUENCING, AND OVEREXPRESSION OF GENES FOR RIBOSOMAL-PROTEINS FROM BACILLUS-STEAROTHERMOPHILUS SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID AMINO-ACID-SEQUENCES; ESCHERICHIA-COLI; CRYSTAL-STRUCTURE; LARGE SUBUNIT; CRYSTALLIZATION; RNA; POLYMERASE; INITIATION; EXPRESSION; MODEL AB Although a low resolution model for the arrangement of the proteins of the small and large ribosomal subunits is known, a detailed mechanistic understanding of the function of the ribosome awaits a high resolution structure of its components. While crystals have been obtained of several ribosomal proteins from Bacillus stearothermophilus, determination of atomic resolution structures of these proteins is impeded by the difficulty of obtaining large amounts of native proteins for crystallographic or NMR studies. We describe here the cloning and overexpression in Escherichia coli of the genes for ribosomal proteins S5, L6, L9, and L18 from B. stearothermophilus. S5 is extremely toxic to E. coli when overexpressed, and we have taken advantage of a new tightly regulated expression system to obtain high yields (more than 100 mg of pure protein/liter of culture) of this protein. The B. stearothermophilus S5 produced in E. coli crystallizes, and the crystals are identical to those obtained from the native protein. The crystals diffract to 2-angstrom resolution. RP RAMAKRISHNAN, V (reprint author), BROOKHAVEN NATL LAB,DEPT BIOL,UPTON,NY 11973, USA. OI Ramakrishnan, V/0000-0002-4699-2194 NR 37 TC 40 Z9 46 U1 0 U2 0 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 JAN 15 PY 1991 VL 266 IS 2 BP 880 EP 885 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ET177 UT WOS:A1991ET17700034 PM 1985969 ER PT J AU VONWRONSKI, MA SHIOTA, S TANO, K MITRA, S BIGNER, DD BRENT, TP AF VONWRONSKI, MA SHIOTA, S TANO, K MITRA, S BIGNER, DD BRENT, TP TI STRUCTURAL AND IMMUNOLOGICAL COMPARISON OF INDIGENOUS HUMAN O6-METHYLGUANINE-DNA METHYLTRANSFERASE WITH THAT ENCODED BY A CLONED CDNA SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID ESCHERICHIA-COLI; O-6-ALKYLGUANINE-DNA ALKYLTRANSFERASE; ALKYLATED DNA; TUMOR-CELLS; REPAIR; GENE; O-6-METHYLGUANINE; SEQUENCE; PROTEINS; PURIFICATION AB O6-Methylguanine-DNA methyltransferase, a ubiquitous and unusual DNA repair protein, eliminates mutagenic and cytotoxic O6-alkylguanine from DNA by transferring the alkyl group to one of its cysteine residues in a second-order suicide reaction. This 22-kDa protein was immunoaffinity-purified to homogeneity from cultured human lymphoblasts (CEM-CCRF line) and compared with the O6-methylguanine-DNA methyltransferase purified to homogeneity from Escherichia coli expressing a cloned human cDNA. The cellular and recombinant proteins were identical in size, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of intact molecules and their peptides. Immunoprobing of Western blots with three monoclonal antibodies specific for human cellular O6-methylguanine-DNA methyltransferase further indicated identity of the two proteins. The amino acid sequence of the cellular protein was experimentally determined for 87 out of a total of 207 residues and was found to be identical to that deduced from the cDNA sequence. A unique cysteine residue at position 145 was identified as the methyl acceptor site by autoradiographic analysis of peptides and sequence analysis of H-3-methylated O6-methylguanine-DNA methyltransferase. These observations establish that the cloned O6-methylguanine-DNA methyltransferase cDNA encodes the full-length O6-methylguanine-DNA methyltransferase polypeptide that is normally present in human cells. Moreover, the cellular protein does not appear to be significantly modified by postranslational processes. C1 UNIV TENNESSEE, GRAD SCH BIOMED SCI, KNOXVILLE, TN 37996 USA. OAK RIDGE NATL LAB, DIV BIOL, OAK RIDGE, TN 37831 USA. DUKE UNIV, MED CTR, DEPT PATHOL, DURHAM, NC 27710 USA. RP VONWRONSKI, MA (reprint author), ST JUDE CHILDRENS RES HOSP, DEPT BIOCHEM & CLIN PHARMACOL, MEMPHIS, TN 38101 USA. FU NCI NIH HHS [CA 11898, CA 31721]; NINDS NIH HHS [NS 20023] NR 37 TC 22 Z9 23 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JAN 15 PY 1991 VL 266 IS 2 BP 1064 EP 1070 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA ET177 UT WOS:A1991ET17700062 PM 1985934 ER PT J AU PIEHLER, D KOT, WK EDELSTEIN, N AF PIEHLER, D KOT, WK EDELSTEIN, N TI THE 6D-]5F FLUORESCENCE-SPECTRA OF PACL62- IN A CS2ZRCL6 CRYSTAL SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC RAMAN-SCATTERING; TRANSITIONS; CE-3+; LUPO4 AB Emission spectra from the parity-allowed electronic transitions between the lowest crystal field level of the 6d1 configuration to all the electronic levels of the 5f1 configuration of Pa4+ diluted into single crystals of Cs2ZrCl6 at 4.2 K show highly structured vibronic sidebands. Vibronic progressions are seen along the 310 cm-1 totally symmetric stretch of the PaCl6(2-) complex. Most vibronic peaks correspond to even parity vibrations of the PaCl6(2-) complex or the host lattice. Additionally, electronic Raman scattering was observed between the two lowest crystal field levels of the 5f1 configuration by exciting with an argon ion laser in near resonance with the lowest level of the 6d1 configuration. RP PIEHLER, D (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. NR 20 TC 23 Z9 23 U1 2 U2 5 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 JAN 15 PY 1991 VL 94 IS 2 BP 942 EP 948 DI 10.1063/1.459984 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EU592 UT WOS:A1991EU59200013 ER PT J AU ROY, P BARTLETT, RJ TRELA, WJ FERRETT, TA PARR, AC SOUTHWORTH, SH HARDIS, JE SCHMIDT, V DEHMER, JL AF ROY, P BARTLETT, RJ TRELA, WJ FERRETT, TA PARR, AC SOUTHWORTH, SH HARDIS, JE SCHMIDT, V DEHMER, JL TI VIBRONIC COUPLING AND OTHER MANY-BODY EFFECTS IN THE 4-SIGMA-G(-1) PHOTOIONIZATION CHANNEL OF CO2 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID PHOTOELECTRON ANGULAR-DISTRIBUTIONS; IONIZATION CROSS-SECTIONS; SHAPE-RESONANCE; HIGH-RESOLUTION; PHOTO-IONIZATION; SYNCHROTRON RADIATION; CARBON-DIOXIDE; ASYMMETRY PARAMETERS; SPECTROMETER SYSTEM; BRANCHING RATIOS AB Vibrational branching ratios and photoelectron angular distributions were measured for 4-sigma-g-1 photoionization of CO2 in the energy range 20-28 eV. Of particular interest are three vibrational components of the resulting CO2+ C approximately 2-SIGMA-g+ state-the allowed (000) and (100) bands and the forbidden (101) band. The wavelength dependence of the beta parameter for the forbidden band deviated significantly from that of the two allowed bands, showing instead a strong resemblance to that of the B approxiately 2-SIGMA-u+ state. This behaviour suggests that vibronic coupling to the B approximately 2-SIGMA-u+ state the responsible for the appearance of the (101) band in the C approximately 2-SIGMA-g+ state photoelectron spectrum. We also observe evidence for other many-body effects-shape-resonance-induced continuum-continuum coupling and doubly excited autoionizing resonances-in the present data. C1 UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. NIST,DIV RADIOMETR,GAITHERSBURG,MD 20899. NIST,DIV RADIAT PHYS,GAITHERSBURG,MD 20899. UNIV FREIBURG,FAK PHYS,W-7800 FREIBURG,GERMANY. ARGONNE NATL LAB,ARGONNE,IL 60439. NR 63 TC 20 Z9 20 U1 0 U2 0 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 JAN 15 PY 1991 VL 94 IS 2 BP 949 EP 956 DI 10.1063/1.459985 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EU592 UT WOS:A1991EU59200014 ER PT J AU PHILLPOT, SR RICKMAN, JM AF PHILLPOT, SR RICKMAN, JM TI CALCULATION OF THE FREE-ENERGY OF SOLIDS FROM THE ENERGY-DISTRIBUTION FUNCTION SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS; FCC AB We outline a new methodology for the calculation of the Helmholtz and the Gibbs free energies from a cumulant analysis of the internal-energy and enthalpy distribution functions obtained from a Monte Carlo simulation at a single temperature. It is validated from a comparison of the free energies calculated for a perfect crystal by using this approach with the free energy calculated from a temperature-integration scheme. The new method allows the calculation of the free energy at all temperatures up to melting from a single Monte Carlo simulation at one temperature only. Thus, it is approximately 3-6 times more computationally efficient than a temperature- integration scheme. By comparing the two methods for an inhomogeneous system containing grain boundaries, we investigate the effects of the distribution of local strain on the free energy; for the superlattice of twist grain boundaries studied here, the effects are found to be small. RP PHILLPOT, SR (reprint author), ARGONNE NATL LAB,DIV MAT SCI,ARGONNE,IL 60439, USA. RI Phillpot, Simon/J-9117-2012; OI Phillpot, Simon/0000-0002-7774-6535 NR 20 TC 26 Z9 26 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 JAN 15 PY 1991 VL 94 IS 2 BP 1454 EP 1464 DI 10.1063/1.460003 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA EU592 UT WOS:A1991EU59200072 ER PT J AU URETSKY, JL AF URETSKY, JL TI PROTHEROE STATISTIC AND CONTINUOUS DISTRIBUTIONS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article AB Protheroe's statistic was originally presented as an algorithm, requiring extensive Monte Carlo calculations for estimation of critical values. I show that the statistic can be defined for continuous distributions. As a result, values of the statistic for uniform distributions and distributions with narrow peaks are easily calculated, as are critical values. C1 COLL DUPAGE,DEPT NAT SCI,GLEN ELLYN,IL 60173. RP URETSKY, JL (reprint author), ARGONNE NATL LAB,DIV HIGH ENERGY PHYS,ARGONNE,IL 60439, USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JAN 15 PY 1991 VL 300 IS 2 BP 351 EP 353 DI 10.1016/0168-9002(91)90447-X PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA435 UT WOS:A1991FA43500016 ER PT J AU BERMAN, LE HART, M AF BERMAN, LE HART, M TI PERFORMANCE OF WATER JET COOLED SILICON MONOCHROMATORS ON A MULTIPOLE WIGGLER BEAM LINE AT NSLS SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID CRYSTAL AB A 27 pole wiggler on the X25 beam line at the National Synchrotron Light Source (NSLS) provides a horizontal X-ray power density of 350 W/mrad with a critical energy of 4.6 keV. Jet cooled silicon crystal monochromators are shown to be capable of almost perfect performance at the experimental position where the available power density is about 45 W/cm of beam width and the total power is about 250 W. Both Si(111) and Si(220) monochromators have been tested and the Bragg angle variation across the beam thermal footprint is shown to be only 2.5 arc sec at the highest power levels. C1 UNIV MANCHESTER,SCHUSTER LAB,DEPT PHYS,MANCHESTER M13 9PL,LANCS,ENGLAND. RP BERMAN, LE (reprint author), BROOKHAVEN NATL LAB,NATL SYNCHROTRON LIGHT SOURCE,UPTON,NY 11973, USA. NR 8 TC 26 Z9 26 U1 3 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 JAN 15 PY 1991 VL 300 IS 2 BP 415 EP 421 DI 10.1016/0168-9002(91)90455-Y PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA FA435 UT WOS:A1991FA43500024 ER PT J AU FEIT, MD FLECK, JA AF FEIT, MD FLECK, JA TI SPATIAL COHERENCE OF LABORATORY SOFT-X-RAY LASERS SO OPTICS LETTERS LA English DT Article AB Employing a time-dependent model with counterpropagating beams and saturable gain, we calculate the degree of coherence for a range of x-ray lasers. From these results we infer a scaling law that can be used to estimate the degree of coherence of a general class of x-ray lasers. RP FEIT, MD (reprint author), UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550, USA. RI Feit, Michael/A-4480-2009 NR 8 TC 14 Z9 14 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 JAN 15 PY 1991 VL 16 IS 2 BP 76 EP 78 DI 10.1364/OL.16.000076 PG 3 WC Optics SC Optics GA EV196 UT WOS:A1991EV19600006 PM 19773842 ER PT J AU CHEN, K BAK, P OBUKHOV, SP AF CHEN, K BAK, P OBUKHOV, SP TI SELF-ORGANIZED CRITICALITY IN A CRACK-PROPAGATION MODEL OF EARTHQUAKES SO PHYSICAL REVIEW A LA English DT Article AB The distribution of seismic moment or energy of earthquakes is well described by the universal Gutenberg-Richter power law, N(s) almost-equal-to s-1-b, where b almost-equal-to 0.5-0.6. We have constructed a simple dynamical model of crack propagation; when driven by slowly increasing shear stress, the model evolves into a self-organized critical state. A power-law distribution for earthquakes with b almost-equal-to 0.4 in two dimensions and b almost-equal-to 0.6 in three dimensions is found. The critical state is "at the edge of chaos," with algebraic growth in time of a small initial perturbation. C1 LD LANDAU THEORET PHYS INST, MOSCOW, USSR. RP BROOKHAVEN NATL LAB, UPTON, NY 11973 USA. NR 26 TC 225 Z9 234 U1 0 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD JAN 15 PY 1991 VL 43 IS 2 BP 625 EP 630 DI 10.1103/PhysRevA.43.625 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600001 ER PT J AU CAMASSA, R WIGGINS, S AF CAMASSA, R WIGGINS, S TI CHAOTIC ADVECTION IN A RAYLEIGH-BENARD FLOW SO PHYSICAL REVIEW A LA English DT Article ID CONVECTION-ROLLS; TRANSPORT; DYNAMICS; FLUID AB We consider the problem of transport of a passive tracer in the time-dependent flow corresponding to a Rayleigh number R slightly above the R(t) at the onset of the even oscillatory instability for Rayleigh-Benard convection rolls. By modeling the flow with a stream function, we show how to construct and identify invariant structures in the flow that act as a "template" for the motion of fluid particles, in the absence of molecular diffusivity. This approach and symmetry considerations allow us to write explicit formulas that describe the tracer transport for finite times. In the limit of small amplitude of the oscillation, i.e., when (R - R(t))1/2 is small, we show that the amount of fluid transported across a roll boundary grows linearly with the amplitude, in agreement with the experimental and numerical findings of Solomon and Gollub [Phys. Rev. A 38, 6280 (1988)]. The presence of molecular diffusivity introduces a (long) time scale into the problem. We discuss the applicability of the theory in this situation, by introducing a simple rule for determining when the effects of diffusivity are negligible, and perform numerical simulations of the flow in this case to provide an example. C1 UNIV CALIF LOS ALAMOS SCI LAB,DIV INFECT DIS,LOS ALAMOS,NM 87545. CALTECH,PASADENA,CA 91125. RP CAMASSA, R (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,CTR NONLINEAR STUDIES,LOS ALAMOS,NM 87545, USA. NR 31 TC 85 Z9 85 U1 0 U2 6 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 JAN 15 PY 1991 VL 43 IS 2 BP 774 EP 797 DI 10.1103/PhysRevA.43.774 PG 24 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600017 ER PT J AU MARTIN, JE WILCOXON, J ODINEK, J AF MARTIN, JE WILCOXON, J ODINEK, J TI DECAY OF DENSITY-FLUCTUATIONS IN GELS SO PHYSICAL REVIEW A LA English DT Article ID DYNAMIC LIGHT-SCATTERING; DILUTE POLYMER-SOLUTIONS; SLOW-MODE DIFFUSION; GELATION THRESHOLD; SEMIDILUTE SOLUTIONS; GLASSLIKE BEHAVIOR; BRANCHED POLYMERS; SELF-DIFFUSION; TRANSITION; FRACTALS AB Near the sol-gel transition, gelling systems exhibit an extremely slow relaxation of thermally driven density fluctuations. We have made a detailed quasielastic light scattering study of the decay of density fluctuations in reacting silica sol-gels in the pre- and post-gel regimes, and at the gel point. In the pre-gel regime the dynamic structure factor S(q,t) for the branched polymer melt has a stretched exponential tail whose characteristic time diverges at the gel point. This critical slowing down is due to the divergence of the average cluster size and is distinct from the usual critical slowing down observed in second-order thermodynamic phase transitions, since the initial decay rate of S(q,t) is nondivergent at the gel point. In fact, at the gel point, S(q,t) becomes a power law, indicating a fractal time set in the scattered field. These observations are accounted for by considering the dynamics of percolation clusters, and in this connection the analogy to viscoelasticity is described. Beyond the gel point S(q,t) remains a power law, but the amplitude of the relaxing part of the intensity autocorrelation function diminishes. Finally, the dynamics of clusters diluted from the reaction bath is studied, and a crossover from power law to stretched exponential decay of S(q,t) is observed. It is shown that at infinite dilution the long-time tail of the correlation function describes the internal modes of a single percolation cluster. RP MARTIN, JE (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 45 TC 203 Z9 203 U1 4 U2 20 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 JAN 15 PY 1991 VL 43 IS 2 BP 858 EP 872 DI 10.1103/PhysRevA.43.858 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600026 ER PT J AU BOSCH, RA GABL, EF SIMPSON, JD ARMENTROUT, CJ FAILOR, BH KANIA, DR BELL, PM AF BOSCH, RA GABL, EF SIMPSON, JD ARMENTROUT, CJ FAILOR, BH KANIA, DR BELL, PM TI EFFECTS OF INDUCED SPATIAL INCOHERENCE ON LASER-LIGHT ABSORPTION AND X-RAY CONVERSION AT 0.53 MU-M SO PHYSICAL REVIEW A LA English DT Article ID RAMAN-SCATTERING; DISK TARGETS; PLASMAS; INSTABILITY; RADIATION; EMISSION; BEAM AB Gold disk targets were irradiated with and without induced spatial incoherence (ISI) at lambda = 0.526-mu-m and intensities of (1-5) X 10(14) W/cm2. The distribution of laser energy on target and M-band x-ray (2-4 keV) pinhole images of the target were smoothed with ISI. Absorption of laser energy was increased by 5-10 % with ISI. Soft-x-ray conversion efficiency with and without ISI were equal within the data scatter and uncertainty of approximately 10 %. C1 EASTERN MICHIGAN UNIV,DEPT PHYS,YPSILANTI,MI 48197. UNIV CALIF LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94550. KMS FUSION INC,ANN ARBOR,MI 48106. RP BOSCH, RA (reprint author), UNIV MICHIGAN,DEPT NUCL ENGN,ANN ARBOR,MI 48109, USA. NR 23 TC 2 Z9 3 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 JAN 15 PY 1991 VL 43 IS 2 BP 953 EP 960 DI 10.1103/PhysRevA.43.953 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA EU856 UT WOS:A1991EU85600034 ER PT J AU WATSON, RE WEINERT, M FERNANDO, GW AF WATSON, RE WEINERT, M FERNANDO, GW TI CHARGE-TRANSFER IN TRANSITION-METAL ALLOYING - CHARGE-TAILING EFFECTS SO PHYSICAL REVIEW B LA English DT Article AB Charge transfer in alloys is normally discussed in terms of band hybridization, band filling, and screening, but at times experiment and theory yield apparently odd results where, for example, rare-earth actinides or elements from the Ti column apparently gain charge from electronegative transition metals such as Fe, Pt, or Au. Here it is observed that there are charge-tailing terms, due to tails of charge associated with an atom's nearest neighbors, which make substantial contributions to the change in charge count at a site in a compound. This is shown with linearized augmented Slater-type-orbital calculations for 5d transition-metal alloys in the ordered CsCl structure. That charge transfer that remains, after the tailing effects are subtracted out, is seen to be consistent with notions concerning electronegativity behavior (though indicating Pt rather than Au to be the most electronegative of the 5d elements). These findings have serious implications for understanding charge transfer and make it necessary to reexamine almost all the arguments relating charge transfer to the bonding of transition metals and, for that matter, of main group elements. RP WATSON, RE (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 8 TC 15 Z9 15 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1446 EP 1454 DI 10.1103/PhysRevB.43.1446 PG 9 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800018 ER PT J AU WATSON, RE FERNANDO, GW WEINERT, M WANG, YJ DAVENPORT, JW AF WATSON, RE FERNANDO, GW WEINERT, M WANG, YJ DAVENPORT, JW TI LOCAL-DENSITY APPROXIMATION - COHESION IN THE TRANSITION-METALS AND S-]D PROMOTION IN THE TRANSITION-METAL ATOMS SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE CALCULATIONS; ORBITAL METHOD; 5D ELEMENTS AB Systematics in cohesive energies (H(coh)) and d-non-d atomic promotion energies have been examined for the transition elements treated within the local-density approximation (LDA). Cohesive energies involve the energy of the solid as compared with that of a reference state in the free atom; going from one atomic configuration to another (e.g., d(n-2)S2-->d(n-1)S) for that reference state involves a promotion energy. Errors in the LDA's ability to calculate promotion energies are then translated into changes in calculated H(coh). Employing the local-spin-density approximation (LSDA), scalar-relativistic values of the promotion energies have been obtained for atomic states of maximum spin multiplicity of the neutral atoms in the 3d, 4d, and 5d rows for those configurations for which experimental spectral data are available for comparison. The intent is that by scanning all three rows and those cases for which there are experimental data that those factors contributing to the LDA's shortcomings in describing electron-electron interactions in the transition elements may become better defined. Previously, other workers have obtained d(n-2)S2-->d(n-1)S promotion energies for the 3d row, indicating that the LDa (or LSDA) significantly overestimates the stability of d valence electrons as compared with the non-d. The more extensive results obtained here indicate that, while often significant, s-->d promotion energy errors are sometimes essentially zero valued. This variation in s-->d promotion energy behavior has implications for what might be presumed to be the shortcomings of the LDA as applied to atoms and, in turn, to solids. Given the promotion energies, the consequences of choosing different references states in estimates of H(coh) for the 4d and 5d rows are explored and an envelope of H(coh) values defined. No matter what the choice of reference state, the LDA significantly overestimates H(coh) in the middle of the transition-element rows, a result consistent with previous estimates. This error becomes small upon going to the noble metals and, as has not been generally recongnized, is essentially zero valued for the beginning members of each row. These matters are discussed. RP WATSON, RE (reprint author), BROOKHAVEN NATL LAB,DEPT PHYS,UPTON,NY 11973, USA. NR 15 TC 26 Z9 26 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 JAN 15 PY 1991 VL 43 IS 2 BP 1455 EP 1462 DI 10.1103/PhysRevB.43.1455 PG 8 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800019 ER PT J AU DELONG, MC VIOHL, I OHLSEN, WD TAYLOR, PC OLSON, JM AF DELONG, MC VIOHL, I OHLSEN, WD TAYLOR, PC OLSON, JM TI MICROWAVE THERMAL MODULATION OF PHOTOLUMINESCENCE IN III-V SEMICONDUCTORS SO PHYSICAL REVIEW B LA English DT Article ID IMPACT IONIZATION; QUANTUM WELLS; EPITAXIAL GAAS; EXCITONS; INP AB The effects of an applied microwave field on low-temperature photoluminescence (PL) have been investigated in epitaxial Ga0.52In0.48P and GaAs. The modulation-frequency dependence of the microwave-modulated PL was compared with the frequency response in nominally identical samples directly heated by an alternating current passing through the sample substrate. We give strong evidence that (1) the mechanism, whereby the microwaves interact with the PL in Ga0.48In0.52P, is via simple heating of the lattice and (2) in superfluid helium the time constant for thermal equilibration of the epilayer to its environment is less than 2-mu-sec, in agreement with theoretical estimates. This thermal-coupling mechanism has been observed in Ga0.52In0.48P, GaAs(x)P1-x, and GaAs1-xSb(x), all of which exhibit a propensity to form ordered structures. The coupling in GaAs, InP, CdS, InP/Ga0.47In0.53As/InP, and GaAs/Al(x)Ga1(-x)As/GaAs is not thermal but may involve impact ionization. C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP DELONG, MC (reprint author), UNIV UTAH,DEPT PHYS,SALT LAKE CITY,UT 84112, USA. NR 37 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1510 EP 1519 DI 10.1103/PhysRevB.43.1510 PG 10 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800025 ER PT J AU MAGRI, R ZUNGER, A AF MAGRI, R ZUNGER, A TI THERMODYNAMIC INSTABILITY OF ORDERED (001) ALGAAS2 IN BULK FORM SO PHYSICAL REVIEW B LA English DT Article ID VAPOR-PHASE EPITAXY; LONG-RANGE ORDER; SEMICONDUCTOR ALLOYS; III-V; DIAGRAMS; SUPERLATTICES; ALXGA1-XAS; STABILITY; DENSITY; ENERGY AB Recent tight-binding calculations of bulk electronic total energies by Koiller, Davidovich, and Falicov (KDF) [Phys. Rev. B 41, 3670 (1990)] indicated the tendency for Al1-xGa(x)As alloys to form ordered structures. The stablest structure they predicted was the monolayer (AlAs)1(GaAs)1[001] superlattice, which was recently observed in homogeneous vapor-phase growth. In light of these results we have examined the possibility that bulk energetics can explain this ordering. We have subjected KDF's tight-binding total-energy calculations and, separately, our own first-principles pseudopotential total-energy calculations to a statistical-mechanics analysis of order-disorder transitions. We find that bulk thermodynamics is inconsistent with the observed ordering; hence, explanations must be sought elsewhere (e.g., surface thermodynamics or kinetic effects). RP MAGRI, R (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013; Magri, Rita/O-5267-2016 OI Magri, Rita/0000-0003-2945-0374 NR 43 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 JAN 15 PY 1991 VL 43 IS 2 BP 1584 EP 1592 DI 10.1103/PhysRevB.43.1584 PG 9 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800031 ER PT J AU MAGRI, R BERNARD, JE ZUNGER, A AF MAGRI, R BERNARD, JE ZUNGER, A TI PREDICTING STRUCTURAL ENERGIES OF ATOMIC LATTICES SO PHYSICAL REVIEW B LA English DT Article ID SEMICONDUCTOR PHASE-DIAGRAMS; TRANSITION-METAL ALLOYS; SUPERLATTICES; STABILITY; DENSITY; ORDER; STATE AB The complexity of current ab initio quantum-mechanical calculations of the total energy of given distributions of atoms on a periodic lattice often limits explorations to just a few configurations. We show how such a small number of calculations can be used instead to compute the interaction energies of a generalized Ising model, which then readily provides predicted energies of many more interesting configurations. This is illustrated for AlAs/GaAs systems. RP MAGRI, R (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013; Magri, Rita/O-5267-2016 OI Magri, Rita/0000-0003-2945-0374 NR 21 TC 15 Z9 15 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1593 EP 1597 DI 10.1103/PhysRevB.43.1593 PG 5 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800032 ER PT J AU SHINAR, J SHINAR, R WU, XL MITRA, S GIRVAN, RF AF SHINAR, J SHINAR, R WU, XL MITRA, S GIRVAN, RF TI HYDROGEN DYNAMICS IN A-SI-H - MULTIPLE TRAPPING, STRUCTURAL RELAXATION, AND THE MEYER-NELDEL RELATION SO PHYSICAL REVIEW B LA English DT Article ID INDUCED METASTABLE DEFECTS; AMORPHOUS-SILICON; CONDUCTIVITY CHANGES; DIFFUSION; SCATTERING; GERMANIUM; MOTION AB The power-law time-dependent diffusion constant D(t) = D00(wt)-alpha was measured in undoped hydrogenated amorphous silicon of varying H content [H(t)], diffusion length L, and microvoid content at temperatures T less-than-or-equal-to 400-degrees-C. alpha generally deviates from a 1 - T/T0 dependence on the temperature T. The temperature dependence of D(t(L)), for constant L, thus deviates from an Arrhenius behavior. The "apparent" activation energy E(a) and prefactor D0, defined by the linear best fit of 1nD(t(L)) versus 1/T, strongly increase with L at low [H(t)]. The Meyer-Neldel relation D0 = A00 exp(E(a)/kT'0), where A00 congruent-to 3.1 x 10(-14) cm2/s an T'0 congruent-to 30 K, holds for all 1.3 less-than-or-equal-to E(a) less-than-or-equal-to 2.4 eV and 2.5 x 10(-5) less-than-or-equal-to D0 less-than-or-equal-to 3100 cm2/s. Structural relaxation processes dependent on H content are believed to affect alpha. The nature of the microvoid-related deep H-trapping sites is also discussed. C1 IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011. IOWA STATE UNIV SCI & TECHNOL,MICROELECTR RES CTR,AMES,IA 50011. RP SHINAR, J (reprint author), IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011, USA. NR 37 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 JAN 15 PY 1991 VL 43 IS 2 BP 1631 EP 1636 DI 10.1103/PhysRevB.43.1631 PG 6 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800037 ER PT J AU STEINER, MM ALBERS, RC SCALAPINO, DJ SHAM, LJ AF STEINER, MM ALBERS, RC SCALAPINO, DJ SHAM, LJ TI PERTURBATION-THEORY OF THE ELECTRONIC-PROPERTIES IN STRONGLY CORRELATED SOLIDS SO PHYSICAL REVIEW B LA English DT Article ID PERIODIC ANDERSON MODEL; FERMI-SURFACE; TRANSITION-METALS; LATTICE MODEL; MIXED-VALENCE; GROUND-STATE; INSULATORS; DENSITY; SYSTEMS; SEMICONDUCTORS AB In an attempt to obtain a better description than the local-density approximation (LDA) for the electronic structure of realistic narrow-band systems, we have studied a perturbation-theory method for the self-energy and have tested it on the electronic properties of the periodic one-dimensional Anderson model. For a number of models we have calculated a wide range of properties such as quasiparticle energies, spectral densities, reduced hybridizations, and various magnetic correlation functions. For two different models we were able to compare with Monte Carlo results and found good agreement. In general, we have obtained a description of narrow-band systems that is more reasonable that the one given by the LDA. C1 UNIV CALIF SAN DIEGO,DEPT PHYS B-019,LA JOLLA,CA 92093. UNIV CALIF SANTA BARBARA,DEPT PHYS,SANTA BARBARA,CA 93106. RP STEINER, MM (reprint author), UNIV CALIF LOS ALAMOS SCI LAB,DIV THEORET MS-B262,LOS ALAMOS,NM 87545, USA. OI Sham, Lu/0000-0001-5718-2077 NR 45 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1637 EP 1650 DI 10.1103/PhysRevB.43.1637 PG 14 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800038 ER PT J AU WEI, SH ZUNGER, A AF WEI, SH ZUNGER, A TI DISORDER EFFECTS ON THE DENSITY OF STATES OF THE II-VI SEMICONDUCTOR ALLOYS HG0.5CD0.5TE, CD0.5ZN0.5TE, AND HG0.5ZN0.5TE SO PHYSICAL REVIEW B LA English DT Article ID COHERENT-POTENTIAL APPROXIMATION; ABSORPTION FINE-STRUCTURE; VALENCE-BAND DENSITIES; SITE DIAGONAL DISORDER; RANDOM SOLID-SOLUTIONS; PLANE-WAVE METHOD; ELECTRONIC-STRUCTURE; PSEUDOBINARY ALLOYS; 3-DIMENSIONAL ALLOY; ENERGY-GAP AB The electronic structure of substitutionally random A1-xB(x)C alloys of zinc-blende semiconductors AC and BC departs from what a virtual-crystal approximation would grant both because of (i) a chemical perturbation, associated with an electronic mismatch between atoms A and B, and because of (ii) a structural perturbation (positional relaxation) induced by a size mismatch between A and B. Both effects on the electronic density of states are studied here for Hg0.5Cd0.5Te, Cd0.5Zn0.5Te, and Hg0.5Zn0.5Te in the context of first-principles self-consistent supercell models. We use our recently developed "special quasirandom structures" [A. Zunger, S.-H. Wei, L. G. Ferreira, and J. E. Bernard, Phys. Rev. Lett. 65, 353 (1990)] concept whereby lattice sites of a periodic structure are occupied by A and B atoms so as to closely reproduce the structural correlation functions of an infinite, perfectly random alloy. Total-energy minimization provides then the relaxed atomic positions while application of the local-density formalism, as implemented by the linearized augmented-plane-wave method, describes self-consistently the consequences of chemical and structural perturbations. We show how these perturbations lead both to (i) distinct A-like and B-like features in the density of states and the electronic charge densities, and even to (ii) different C-like features associated with fluctuations in the local environments around the common sublattice. RP WEI, SH (reprint author), SOLAR ENERGY RES INST,GOLDEN,CO 80401, USA. RI Zunger, Alex/A-6733-2013 NR 79 TC 83 Z9 84 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1662 EP 1677 DI 10.1103/PhysRevB.43.1662 PG 16 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800040 ER PT J AU IYETOMI, H VASHISHTA, P KALIA, RK AF IYETOMI, H VASHISHTA, P KALIA, RK TI INTEGRAL-EQUATION APPROACH TO MEDIUM-RANGE ORDER IN MOLTEN AND GLASSY CHALCOGENIDES SO PHYSICAL REVIEW B LA English DT Article ID SILICON STRUCTURAL ENERGIES; X-RAY-SCATTERING; NEUTRON-DIFFRACTION; AMORPHOUS GESE2; LIQUID; EXTENSION; DENSITY; AS2SE3; STATES; FLUIDS AB The first sharp diffraction peak (FSDP), a signature of medium-range order in molten and vitreous chalcogenides, is investigated using the integral-equation method. A variety of interatomic potentials, including uncharged and charged hard spheres, and realistic two-body interactions, are used in this study. The two-body potential consists of steric repulsions, Coulomb interactions due to charge-transfer effects, and the effects of electronic polarizability of ions. GeSe2 is treated as a specific example. The FSDP is observed in both the charged-hard-sphere and the realistic two-body interaction models. In both models steric and charge-transfer effects are found to give rise to Ge(Se1/2)4 tetrahedra whose packing determines the medium-range order and the attendant FSDP. From the charge-charge structure factor it is found that the FSDP arises from spatial correlations where charge neutrality prevails. The nature of the medium-range correlation is elucidated through the temperature and density dependence of the FSDP and the thermal expansion determined from the shifts of the peaks in the static structure factor. We have also studied the effects of the potential parameters on the position of the FSDP. The results of the hypernetted-chain theory are compared with the molecular-dynamics results. RP IYETOMI, H (reprint author), ARGONNE NATL LAB, DIV MAT SCI, ARGONNE, IL 60439 USA. NR 49 TC 50 Z9 50 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1726 EP 1734 DI 10.1103/PhysRevB.43.1726 PG 9 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800047 ER PT J AU POGATSHNIK, GJ CAIN, LS CHEN, Y EVANS, BD AF POGATSHNIK, GJ CAIN, LS CHEN, Y EVANS, BD TI OPTICAL-PROPERTIES OF COLOR-CENTERS IN CALCIUM-STABILIZED GADOLINIUM GALLIUM GARNETS SO PHYSICAL REVIEW B LA English DT Article ID YTTRIUM-ALUMINUM GARNET; SINGLE-CRYSTALS; LUMINESCENCE; GGG AB The addition of small amounts of calcium during the crystal growth of large-diameter, gadolinium gallium garnet (GGG) crystals creates color centers that absorb in the near-uv region of the spectrum. Ultraviolet and gamma-ray irradiation of the crystals produced changes in the intensities of the uv color-center bands along with a broad absorption throughout the visible spectrum. The color center that gives rise to an absorption band at 350 nm serves as a photoionizable donor center so that uv excitation results in a visible coloration of the crystals. The effects of oxidation and reduction treatments on the strength of the color-center bands and on the radiation response of the material were examined. Photoluminescence bands were observed in both reduced GGG crystals as well as crystals that were irradiated with neutrons. Visible coloration is likely to occur during flash-lamp pumping of laser rods that utilize large-diameter GGG crystals as the laser host. The changes in the optical properties of the material under uv excitation indicate that the addition of small amounts of calcium to assist in the growth of large-diameter crystals is likely to result in the degradation of laser performance. C1 DAVIDSON COLL,DEPT PHYS,DAVIDSON,NC 28036. OAK RIDGE NATL LAB,DIV SOLID STATE,OAK RIDGE,TN 37831. BOEING ELECTR CO,SEATTLE,WA 98124. RP POGATSHNIK, GJ (reprint author), SO ILLINOIS UNIV,DEPT PHYS,EDWARDSVILLE,IL 62026, USA. NR 18 TC 16 Z9 17 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 2 BP 1787 EP 1794 DI 10.1103/PhysRevB.43.1787 PG 8 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800055 ER PT J AU LIU, AY GARCIA, A COHEN, ML GODWAL, BK JEANLOZ, R AF LIU, AY GARCIA, A COHEN, ML GODWAL, BK JEANLOZ, R TI THEORY OF HIGH-PRESSURE PHASES OF PB SO PHYSICAL REVIEW B LA English DT Note ID PSEUDOPOTENTIALS; CRYSTAL; SOLIDS; LEAD AB We have studied the behavior of Pb at high pressure using the first-principles pseudopotential total-energy method, with spin-orbit effects treated within perturbation theory. Our calculations agree with recent experiments that indicate that Pb undergoes a phase transition to the bcc structure at pressures on the order of 100 GPa. C1 UNIV CALIF BERKELEY,DEPT GEOL & GEOPHYS,BERKELEY,CA 94720. UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT & CHEM SCI,BERKELEY,CA 94720. RP LIU, AY (reprint author), UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720, USA. RI Garcia, Alberto/A-7460-2008; Liu, Amy/E-2266-2015 OI Garcia, Alberto/0000-0001-5138-9579; Liu, Amy/0000-0002-2011-1854 NR 24 TC 24 Z9 25 U1 2 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 JAN 15 PY 1991 VL 43 IS 2 BP 1795 EP 1798 DI 10.1103/PhysRevB.43.1795 PG 4 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800056 ER PT J AU KWON, I BISWAS, R SOUKOULIS, CM AF KWON, I BISWAS, R SOUKOULIS, CM TI MOLECULAR-DYNAMICS SIMULATIONS OF THE STABILITY OF AMORPHOUS-SILICON SO PHYSICAL REVIEW B LA English DT Note ID DEFECTS; SI; SEMICONDUCTORS; GENERATION AB We have performed molecular-dynamics simulations as a first step towards understanding the Staebler-Wronski effect in amorphous silicon, utilizing classical silicon potentials and computer-generated amorphous silicon structures. A localized hot spot is used to model the nonradiative transfer of photoexcited carrier energy to the lattice. This leads to structural degradation in a-Si networks in which weak Si-Si bonds are broken and dangling bonds are produced, requiring a threshold energy of about 0.8-1.0 eV. Thermal annealing of an a-Si model with coordination defects is also described. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP KWON, I (reprint author), IOWA STATE UNIV SCI & TECHNOL,MICROELECTR RES CTR,AMES,IA 50011, USA. RI Soukoulis, Costas/A-5295-2008 NR 19 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 JAN 15 PY 1991 VL 43 IS 2 BP 1859 EP 1862 DI 10.1103/PhysRevB.43.1859 PG 4 WC Physics, Condensed Matter SC Physics GA ET218 UT WOS:A1991ET21800075 ER PT J AU KIM, KJ HARMON, BN LYNCH, DW AF KIM, KJ HARMON, BN LYNCH, DW TI CALCULATION OF THE OPTICAL-SPECTRA OF BETA'-NIAL AND COAL SO PHYSICAL REVIEW B LA English DT Article ID TRANSITION-METALS V; ELECTRONIC-STRUCTURE; BAND-STRUCTURE; ALLOYS; PHOTOABSORPTION; DENSITY; STATES; NICKEL; ENERGY; IRON AB Band structures of beta'-NiAl and CoAl have been calculated to interpret the experimental optical spectra. The optical transitions of both compounds are calculated as direct interband transitions including electric-dipole matrix elements between the eigenstates of the ground state of the system. All of the structures found in the optical spectra of both compounds involve states with some Ni or Co d character in both the initial and the final states. The overall agreement is good between the calculated spectrum and the optical data for beta'-NiAl. For beta'-CoAl there is qualitative agreement but some discrepancy for the energy positions and the intensities of the structures. A self-energy correction for the excitation spectrum has been used for beta'-CoAl to improve the agreement. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. RP KIM, KJ (reprint author), IOWA STATE UNIV SCI & TECHNOL,DEPT PHYS,AMES,IA 50011, USA. NR 26 TC 25 Z9 25 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 3 BP 1948 EP 1953 DI 10.1103/PhysRevB.43.1948 PG 6 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500008 ER PT J AU XU, JH LIN, W FREEMAN, AJ AF XU, JH LIN, W FREEMAN, AJ TI TWIN-BOUNDARY AND STACKING-FAULT ENERGIES IN AL AND PD SO PHYSICAL REVIEW B LA English DT Article AB The (111) twin-boundary and stacking-fault energies of aluminum and palladium were investigated with use of the all-electron total-energy linear muffin-tin orbitals method based on the local-density approximation. Fault energies are determined by comparing the total energies obtained for the same-size supercells for each of two cases (with and without fault). The calculated values of the twin, intrinsic, and extrinsic fault energies, 130 +/- 15 (97 +/- 5), 270 +/- 50, and approximately 330 ergs/cm2 for aluminum (palladium) are generally 30% larger than experiment. This discrepancy between the calculated and observed values may be attributed to the neglect of relaxation, the effect of the (finite) size of the supercell (at most 28 atoms/cell), and/or the use of the local-density approximation. Our calculated results appear to verify the correctness of the empirical relationship 2E(tw) congruent-to E(SF), where E(tw) and E(SF) are the twin and stacking-fault energies, respectively. C1 NORTHWESTERN UNIV,DEPT PHYS & ASTRON,EVANSTON,IL 60208. ARGONNE NATL LAB,ARGONNE,IL 60439. NR 20 TC 17 Z9 18 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 JAN 15 PY 1991 VL 43 IS 3 BP 2018 EP 2024 DI 10.1103/PhysRevB.43.2018 PG 7 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500014 ER PT J AU BADZIAG, P VERWOERD, WS VANHOVE, MA AF BADZIAG, P VERWOERD, WS VANHOVE, MA TI PREDICTION OF THE EFFECT OF THE SAMPLE BIASING IN SCANNING TUNNELING MICROSCOPY AND OF SURFACE-DEFECTS ON THE OBSERVED CHARACTER OF THE DIMERS IN THE SI(001)-(2X1) SURFACE SO PHYSICAL REVIEW B LA English DT Article ID QUANTUM-CHEMICAL METHODS; SOLID-STATE APPLICATIONS; CLUSTER CALCULATIONS; SEMICONDUCTOR SURFACES; ELECTRON-DIFFRACTION; SI(100) SURFACES; TOTAL ENERGY; SILICON; RECONSTRUCTION; MODELS AB Self-consistent quantum-chemical cluster calculations are reported which address the controversy about the presence or absence of dimer buckling in the Si(001)-(2x1) reconstructed surface. The results indicate that biasing the surface, as in the scanning tunneling microscopy (STM) experiment, is likely to produce a relatively symmetric STM image even if dimers in the unbiased surface are buckled, as deduced from scattering experiments. We have also investigated a dimer close to a surface defect, such as a step, and propose a mechanism that makes the dimer there appear buckled to STM. C1 UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720. RP BADZIAG, P (reprint author), UNIV S AFRICA,DEPT PHYS,POB 392,PRETORIA 0001,SOUTH AFRICA. RI Van Hove, Michel/A-9862-2008; Verwoerd, Wynand/A-8320-2010 OI Van Hove, Michel/0000-0002-8898-6921; Verwoerd, Wynand/0000-0001-5489-9101 NR 39 TC 34 Z9 34 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 JAN 15 PY 1991 VL 43 IS 3 BP 2058 EP 2062 DI 10.1103/PhysRevB.43.2058 PG 5 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500019 ER PT J AU MARTINS, JL TROULLIER, N WEI, SH AF MARTINS, JL TROULLIER, N WEI, SH TI PSEUDOPOTENTIAL PLANE-WAVE CALCULATIONS FOR ZNS SO PHYSICAL REVIEW B LA English DT Article ID BAND-STRUCTURE CALCULATIONS; TOTAL-ENERGY; ELECTRONIC-STRUCTURE; MOLECULAR-DYNAMICS; SPACE FORMALISM; LARGE MATRICES; SEMICONDUCTORS; INSULATORS; SOLIDS; ALLOYS AB We calculate the structural and electronic properties of cubic ZnS using a pseudopotential plane-wave method and compare the results with an all-electron linearized-augmented-plane-wave calculation. The agreement between the two electronic structure methods is excellent, and the calculated structural properties are in good agreement with the experimental results. We find that in both calculations the fundamental band gap is underestimated and that the Zn d band is less bound than in experiment. Both effects are due to the use of the local-density approximation. C1 SOLAR ENERGY RES INST,GOLDEN,CO 80401. RP MARTINS, JL (reprint author), UNIV MINNESOTA,DEPT CHEM ENGN & MAT SCI,MINNEAPOLIS,MN 55455, USA. RI Martins, Jose Luis/F-3888-2011 OI Martins, Jose Luis/0000-0002-9061-967X NR 41 TC 109 Z9 110 U1 1 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 3 BP 2213 EP 2217 DI 10.1103/PhysRevB.43.2213 PG 5 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500038 ER PT J AU WADA, N KAMITAKAHARA, WA AF WADA, N KAMITAKAHARA, WA TI INELASTIC NEUTRON-SCATTERING AND RAMAN-SCATTERING STUDIES OF MUSCOVITE AND VERMICULITE LAYERED SILICATES SO PHYSICAL REVIEW B LA English DT Article ID INTERCALATION COMPOUNDS; RIGIDITY; SOLIDS; WATER AB Investigations on the lattice dynamics of muscovite and vermiculite have been carried out by inelastic neutron scattering and Raman scattering. In the neutron measurements, dispersion curves for the out-of-plane and in-plane LA and TA phonons were fully obtained for muscovite, while more limited data were obtained for Mg vermiculite. Sound velocities were estimated from the slopes of the dispersion curves. Raman-scattering experiments revealed an interlayer shearing mode in Na and Sr vermiculites in the O-water-layer hydration state. The intercalated water molecules in Na and Sr vermiculites exhibited a broad Raman feature (OH stretching vibrations) at 3450 cm-1 with a full width at half maximum of approximately 300 cm-1. In addition, relatively sharp Raman peaks from the inner-layer hydroxyls in the host octahedral layers were found at approximately 3700 cm-1. These peaks were sensitive to the hydration state or charge in the intercalated layer. C1 IOWA STATE UNIV SCI & TECHNOL,US DOE,AMES LAB,AMES,IA 50011. UNIV MARYLAND,COLLEGE PK,MD 20742. NATL INST STAND & TECHNOL,GAITHERSBURG,MD 20899. RP WADA, N (reprint author), COLORADO STATE UNIV,DEPT PHYS,FT COLLINS,CO 80523, USA. NR 17 TC 34 Z9 34 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 JAN 15 PY 1991 VL 43 IS 3 BP 2391 EP 2397 DI 10.1103/PhysRevB.43.2391 PG 7 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500062 ER PT J AU LYO, SK AF LYO, SK TI LOW-TEMPERATURE LATTICE-SCATTERING MOBILITY IN MULTIPLE HETEROJUNCTIONS - PHONON-DRAG ENHANCEMENT SO PHYSICAL REVIEW B LA English DT Note ID MODULATION-DOPED HETEROSTRUCTURES; ELECTRON-MOBILITY; GAAS AB The temperature dependence of the low-temperature lattice-scattering mobility (LSM) of a heterojunction as well as a multiple-heterojunction structure is obtained. We show that the LSM of a multiple-heterojunction structure can be significantly enhanced as compared to that of a single heterojunction due to the phonon-drag effect. The high-temperature approximation employed for the LSM in the current literature is found to underestimate significantly the LSM as well as the deformation-potential coefficient. RP LYO, SK (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 12 TC 8 Z9 8 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 JAN 15 PY 1991 VL 43 IS 3 BP 2412 EP 2414 DI 10.1103/PhysRevB.43.2412 PG 3 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500067 ER PT J AU EMIN, D HART, CF AF EMIN, D HART, CF TI EXISTENCE OF WANNIER-STARK LOCALIZATION - REPLY SO PHYSICAL REVIEW B LA English DT Letter AB The argument of Emin and Hart is not that the staircase potential does not couple Bloch states of different energy bands; it does. Rather, the net effect of such interband terms on Wannier-Stark localization is argued to vanish. A new proof of a relationship disputed by Page and Brown is presented. The contradiction that Page and Brown claim results from this relationship is shown to be an artifact of their use of an incomplete set of basis states. C1 SO ILLINOIS UNIV,DEPT PHYS,CARBONDALE,IL 62901. RP EMIN, D (reprint author), SANDIA NATL LABS,ALBUQUERQUE,NM 87185, USA. NR 7 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 0163-1829 J9 PHYS REV B JI Phys. Rev. B PD JAN 15 PY 1991 VL 43 IS 3 BP 2426 EP 2430 DI 10.1103/PhysRevB.43.2426 PG 5 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500071 ER PT J AU YU, KM KHACHATURYAN, K WEBER, ER LEE, HP COLAS, EG AF YU, KM KHACHATURYAN, K WEBER, ER LEE, HP COLAS, EG TI SUBSTITUTIONALITY OF TE-RELATED AND SN-RELATED DX CENTERS IN ALXGA1-XAS SO PHYSICAL REVIEW B LA English DT Note ID PERSISTENT PHOTOCONDUCTIVITY; LATTICE-RELAXATION; DOPED ALXGA1-XAS; MODEL; GAAS; ALLOYS; DEEP AB The lattice locations of Te and Sn atoms forming DX centers in Al(x)Ga(1-x)As were determined by particle-induced x-ray emission and ion-beam-channeling methods. The Te atoms were found to be in the As substitutional sites while the Sn atoms were in the Ga(Al) sites. No off-center displacement of Te and Sn larger than 0.14 angstrom from the substitutional sites was observed in either system. C1 UNIV CALIF BERKELEY,DEPT MAT SCI & MINERAL ENGN,BERKELEY,CA 94720. BELL COMMUN RES INC,RED BANK,NJ 07701. RP YU, KM (reprint author), UNIV CALIF BERKELEY LAWRENCE BERKELEY LAB,CTR ADV MAT,DIV MAT & CHEM SCI,BERKELEY,CA 94720, USA. RI Yu, Kin Man/J-1399-2012 OI Yu, Kin Man/0000-0003-1350-9642 NR 19 TC 5 Z9 5 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 JAN 15 PY 1991 VL 43 IS 3 BP 2462 EP 2465 DI 10.1103/PhysRevB.43.2462 PG 4 WC Physics, Condensed Matter SC Physics GA EV605 UT WOS:A1991EV60500080 ER PT J AU MASSAROTTI, A AF MASSAROTTI, A TI EVOLUTION OF LIGHT DOMAIN-WALLS INTERACTING WITH DARK MATTER SO PHYSICAL REVIEW D LA English DT Article ID STRINGS AB In this paper we discuss the evolution of domain walls generated in the early Universe considering, unlike the previous studies, an interaction between the walls and a major gaseous component of the dark matter. It is assumed that the walls can reflect the particles elastically and with a reflection coefficient of unity. We discuss a toy Lagrangian that could give rise to such a phenomenon. In the simple model studied we obtain highly nonrelativistic and slowly varying speeds for the domain walls [approximately 10(-2)(1+z)-1] and negligible distortions of the microwave background. In addition, these topological defects may provide a mechanism of forming the large-scale structure of the Universe, by creating fluctuations in the dark matter delta-rho/rho-approximately 1 on a scale comparable to the distance the walls move from the formation (in our model this distance could be even tens of Mpc). The characteristic scale of the wall separation can be easily chosen to be of the order of 100 Mpc instead of being restricted to the horizon scale, as usually obtained. C1 NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,BATAVIA,IL 60510. RP MASSAROTTI, A (reprint author), UNIV CHICAGO,DEPT PHYS,CHICAGO,IL 60637, USA. NR 14 TC 13 Z9 13 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1991 VL 43 IS 2 BP 346 EP 352 DI 10.1103/PhysRevD.43.346 PG 7 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ET217 UT WOS:A1991ET21700009 ER PT J AU GREGORY, R AF GREGORY, R TI EFFECTIVE ACTIONS FOR BOSONIC TOPOLOGICAL DEFECTS SO PHYSICAL REVIEW D LA English DT Article ID STRINGS AB We consider a gauge field theory which admits p-dimensional topological defects, expanding the equations of motion in powers of the defect thickness. In this way we derive an effective action and effective equation of motion for the defect in terms of the coordinates of the p-dimensional world surface defined by the history of the core of the defect. RP GREGORY, R (reprint author), NASA,FERMILAB ASTROPHYS CTR,FERMI NATL ACCELERATOR LAB,POB 500,BATAVIA,IL 60510, USA. NR 12 TC 38 Z9 38 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 JAN 15 PY 1991 VL 43 IS 2 BP 520 EP 525 DI 10.1103/PhysRevD.43.520 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ET217 UT WOS:A1991ET21700027 ER PT J AU LOHE, MA BIEDENHARN, LC LOUCK, JD AF LOHE, MA BIEDENHARN, LC LOUCK, JD TI TENSOR OPERATOR FORMULATION OF WEYL-ORDERED POLYNOMIALS SO PHYSICAL REVIEW D LA English DT Note ID DIFFERENTIAL-EQUATIONS AB Weyl-ordered polynomials, which have been used recently to solve quantum-mechanical models, are shown to be equivalent to symplecton polynomials defined previously as components of a tensor operator in SU(2). These polynomials are shown to be expressible in terms of hypergeometric functions of argument-1, providing thereby a direct derivation of their properties. C1 DUKE UNIV,DEPT PHYS,DURHAM,NC 27706. UNIV CALIF LOS ALAMOS SCI LAB,LOS ALAMOS,NM 87545. RI Lohe, Max/C-3193-2012 NR 12 TC 9 Z9 9 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JAN 15 PY 1991 VL 43 IS 2 BP 617 EP 619 DI 10.1103/PhysRevD.43.617 PG 3 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA ET217 UT WOS:A1991ET21700040 ER PT J AU HANSON, LK AF HANSON, LK TI ENVIRONMENTALLY INDUCED SPECTRAL SHIFTS OF OXIDIZED LUMIFLAVIN - CHARGE-TRANSFER AND ELECTROCHROMIC EFFECTS SO THEOCHEM-JOURNAL OF MOLECULAR STRUCTURE LA English DT Article; Proceedings Paper CT CONF ON THEORY OF ENVIRONMENTAL EFFECTS ON MOLECULAR STRUCTURE AND CHEMICAL REACTIVITY CY JUN 26-JUL 01, 1989 CL ST JOHNS, CANADA SP MEM UNIV NEWFOUNDLAND, THEORET ORGAN CHEM, CANADIAN SOC CHEM, WORLD ASSOC THEORET ORGAN CHEMISTS, NAT SCI & ENGN RES COUNCIL CANADA, PROV NEWFOUNDLAND, AIR CANADA ID DIFFERENTIAL-OVERLAP TECHNIQUE; TOTALLY OPTIMIZED GEOMETRIES; INTERMEDIATE NEGLECT; CIRCULAR-DICHROISM; FLAVINS; SPECTROSCOPY; ISOALLOXAZINE; SEPARATION; RADICALS AB Spectroscopic INDO calculations have been performed on molecular complexes of lumiflavin and lumiflavin in the presence of point charges. In complexes with appropriate "ligands", both model flavins and certain flavoenzymes exhibit red-shifted absorption spectra. In addition, red-shifted flavoprotein spectra may arise from the presence of nearby charged amino acid residues. Optical spectra have been calculated for stacked charge transfer complexes of lumiflavin and anthranilic acid based on crystal coordinates (H.-S. Shieh et al., Biochemistry, 20 (1981) 4766). Calculations on 1:1 complexes red shifted the lowest energy pi --> pi* transition relative to lumiflavin by ca. 1400 cm-1 and added an out-of-plane (z) component to its transition moment vector. The red shift arises from a destabilization of the highest occupied molecular orbital (HOMO) which, in the complex, contains about 50% contribution from the anthranilic acid. The lowest unoccupied molecular orbital (LUMO) remains > 98% lumiflavin; its energy is unaffected by the presence of the anthranilic acid. These results demonstrate that the lowest energy transition of the 1:1 complex reflects a transfer of net charge from the anthranilic acid donor (HOMO) to the lumiflavin acceptor (LUMO). The addition of an "extra" lumiflavin to the stack dramatically decreased the calculated red shift because of lumiflavin-lumiflavin exciton interactions that favored the enhancement of a higher energy component. These interactions were found to be very dependent on the relative lateral displacement of the lumiflavin subunits. The electrostatic shifts induced by positive and negative point charges placed both 3.5 angstrom above the lumiflavin and in-plane 2 angstrom outside the van der Waals surface were also calculated. Red shifts of various magnitudes were obtained with both positive and negative charges at all positions, except within a plane that lies roughly normal to the transition dipole direction of the lowest energy pi --> pi* transition and bisects the flavin. These results suggest that charged amino acid groups within flavoproteins will induce mostly red shifts. RP HANSON, LK (reprint author), BROOKHAVEN NATL LAB,DEPT APPL SCI,UPTON,NY 11973, USA. NR 29 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-1280 J9 THEOCHEM-J MOL STRUC JI Theochem-J. Mol. Struct. PD JAN 15 PY 1991 VL 72 IS 1-2 BP 111 EP 127 PG 17 WC Chemistry, Physical SC Chemistry GA EX422 UT WOS:A1991EX42200009 ER EF