FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Enjalran, M Scalettar, RT Kauzlarich, SM AF Enjalran, M Scalettar, RT Kauzlarich, SM TI Magnetic states in frustrated bilayer models: The ordered phase of mixed-layer pnictide oxides SO PHYSICAL REVIEW B LA English DT Article ID HEISENBERG-ANTIFERROMAGNET; NEUTRON-DIFFRACTION; CRYSTAL-STRUCTURE; TRANSITIONS; INTERGROWTH; COMPOUND; LATTICE; SB AB We present results from a numerical investigation of bilayer classical spin systems with local interactions and frustration caused by lattice geometry. We find that when two identical square planes are displaced by half a lattice constant in one direction, a transition to a uniformly twisted spin state occurs at J/J(perpendicular to) greater than or equal to 0.25. An orthogonal state between layers is obtained in the limit T=0 and J(perpendicular to)=0. If instead the two layers are offset along a diagonal, we obtain the phase diagram of the classical J(1)-J(2) model. A weakly canted phase is observed at the classical transition point of J/J(perpendicular to) = 0.5, but frustration does not drive the system towards a state of orthogonal interlayer order. We propose a simple bilayer model with two inequivalent square lattices to study the frustrating interactions of the mixed layer pnictide oxides (Sr(2)Mn(3)Pn(2)O(2), Pn=As,Sb). We find a ground state composed of two independent Neel ordered layers when the interlayer exchange is an order of magnitude weaker than the intralayer exchange, as suggested by experiment. Evidence for local orthogonal order between the layers is found, but it occurs in regions of parameter space which are not experimentally realized. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Calif Lawrence Livermore Natl Lab, Mat Res Inst, Livermore, CA 94550 USA. Univ Calif Davis, Dept Chem, Davis, CA 95616 USA. RP Enjalran, M (reprint author), Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RI Kauzlarich, Susan/H-1439-2011 NR 33 TC 9 Z9 9 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD JUN 1 PY 2000 VL 61 IS 21 BP 14570 EP 14580 DI 10.1103/PhysRevB.61.14570 PG 11 WC Physics, Condensed Matter SC Physics GA 321DB UT WOS:000087438700055 ER PT J AU Montenegro, FC Belanger, DP Slanic, Z Fernandez-Baca, JA AF Montenegro, FC Belanger, DP Slanic, Z Fernandez-Baca, JA TI Ordering in the dilute weakly anisotropic antiferromagnet Mn0.35Zn0.65F2 SO PHYSICAL REVIEW B LA English DT Article ID FIELD ISING-MODEL; SPIN-GLASS BEHAVIOR; NEUTRON-SCATTERING; PERCOLATION-THRESHOLD; RANDOM-EXCHANGE; SYSTEM FEXZN1-XF2; ANTI-FERROMAGNETS; HEAT-CAPACITY; X-RAY; CROSSOVER AB The highly diluted antiferromagnet Mn0.35Zn0.65F2 has been investigated by neutron scattering in zero field. The Bragg peaks observed below the Neel temperature (T(N)approximate to 10.9 K) indicate stable antiferromagnetic (AF) long-range ordering at low temperature. The critical behavior is compatible with random-exchange Ising model critical exponents (nu approximate to 0.69 and gamma approximate to 1.31), as reported for MnchiZn1-chiF2 With higher chi and for the isostructural compound FechiZn1-chiF2. However, in addition to the Bragg peaks, unusual scattering behavior appears around the (1 0 0) AF Bragg peak below a glassy temperature T(g)approximate to 7.0 K. The glassy region T((e) over right arrow,e') experiments. An exhaustive comparison of these results with available data from the TUNL and Wisconsin groups for pd capture, and from the Saskatoon group for threshold electrodisintegration of He-3, is carried out. The calculations are based on pair-correlated-hyperspherical-harmonics bound and continuum wave functions obtained from a realistic Hamiltonian consisting of the Argonne v(18) two-nucleon and Urbana IX three-nucleon interactions. The electromagnetic current operator includes one- and two-body components, leading terms of which are constructed from the Argonne v(18) interaction. The theoretical predictions obtained by including only one-body currents are in violent disagreement with data. These differences between theory and experiment are, to a large extent, removed when two-body currents are taken into account, although some rather large discrepancies remain in the c.m. energy range 0-100 keV, particularly for the pd differential cross section sigma(theta) and tensor analyzing power T-20(theta) at small angles, and contributions to the GDH integral. A rather detailed analysis indicates that these discrepancies have, in large part, a common origin, and can be traced back to an excess of E-1 strength obtained in the theoretical calculation as compared to that observed experimentally. It is suggested that this fact might have implications-for the nuclear interaction at very low energies. Finally, the validity of the long-wavelength approximation for electric dipole transitions is discussed. C1 Ist Nazl Fis Nucl, Sez Pisa, I-56100 Pisa, Italy. Old Dominion Univ, Dept Phys, Norfolk, VA 23529 USA. Jefferson Lab, Newport News, VA 23606 USA. RP Viviani, M (reprint author), Ist Nazl Fis Nucl, Sez Pisa, I-56100 Pisa, Italy. RI kievsky, alejandro/A-7123-2011 NR 47 TC 60 Z9 60 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 JUN PY 2000 VL 61 IS 6 AR 064001 DI 10.1103/PhysRevC.61.064001 PG 18 WC Physics, Nuclear SC Physics GA 323PW UT WOS:000087575000007 ER PT J AU Wang, F Liu, H Sorge, H Xu, N Yang, J AF Wang, F Liu, H Sorge, H Xu, N Yang, J TI Systematic study of the kaon to pion multiplicity ratios in heavy-ion collisions SO PHYSICAL REVIEW C LA English DT Article ID QUARK-GLUON PLASMA; NUCLEUS-NUCLEUS COLLISIONS; STRANGE PARTICLE-PRODUCTION; PROTON-NUCLEUS; PB COLLISIONS; ULTRARELATIVISTIC ENERGIES; QUANTUM CHROMODYNAMICS; VACUUM EXCITATION; PHASE-TRANSITION; STRING FUSION AB We present a systematic study of the kaon to pion multiplicity ratios (K+/pi(+) and K-/pi(-)) in heavy-ion collisions from AGS to RHIC energy using the relativistic quantum molecular dynamics (RQMD) model. The model describes reasonably well the available experimental data on K+/pi(+) and K-/pi(-). Within the model, we find that the strong increase of the ratios with the number of participants is mainly due to hadronic rescattering of produced mesons with ingoing baryons and their resonances. The enhancement of K/pi in heavy-ion collisions with respect to elementary p+p interactions is larger at AGS than SPS energy, and decreases smoothly with bombarding energy. The total multiplicity ratios at RHIC energy are predicted by RQMD to be K+/pi(+)=0.19 and K-/pi(-)=0.15. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Kent State Univ, Dept Phys, Kent, OH 44242 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. RP Wang, F (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 76 TC 30 Z9 30 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2813 J9 PHYS REV C JI Phys. Rev. C PD JUN PY 2000 VL 61 IS 6 AR 064904 DI 10.1103/PhysRevC.61.064904 PG 10 WC Physics, Nuclear SC Physics GA 323PW UT WOS:000087575000063 ER PT J AU Wang, XN AF Wang, XN TI Systematic study of high p(T) hadron spectra in pp, pA, and AA collisions at ultrarelativistic energies SO PHYSICAL REVIEW C LA English DT Article ID TRANSVERSE-MOMENTUM DISTRIBUTION; HEAVY-ION COLLISIONS; TO-LEADING ORDER; QUARK-GLUON PLASMA; LUND MONTE-CARLO; NUCLEAR COLLISIONS; PARTON DISTRIBUTIONS; JET FRAGMENTATION; BOSON PRODUCTION; KAON PRODUCTION AB High-p(T) particle spectra in p + p ((p) over bar + p), p + A, and A + B collisions are calculated in a parton model with QCD-inspired hard scattering and evolution in which intrinsic transverse momentum, its broadening due to initial multiple parton scattering, and jet quenching due to parton energy loss inside a dense medium are included phenomenologically. The intrinsic k(T) and its broadening in p + A and A + B collisions due to initial multiple parton scattering are found to be very important at low energies (root s<50 GeV). Comparisons with S + S, S + Au, and Pb + Pb data with different centrality cuts show that the differential cross sections of large p(T) pion production (p(T) > 1 GeV/c) in A + B collisions scale very well with the number of binary nucleon-nucleon collisions (modulo effects of multiple initial scattering). This suggests that hard parton scattering is the dominant particle production mechanism underlying the hadron spectra at p(T)similar to 2-10 GeV/c. However, there is no evidence of jet quenching or parton energy loss. Assuming this model of parton scattering, nuclear broadening and parton energy loss, one can exclude an effective parton energy loss dE(q)/dx>0.01 GeV/fm and a mean free path lambda(q)<7 fm from the experimental data of A + B collisions at the SPS energies. Predictions for high p(T) particle spectra in p + A and A + A collisions with and without jet quenching at the RHIC energy are also given. Uncertainties due to initial multiple scattering and nuclear shadowing of parton distributions are also discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Wang, XN (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Mailstop 70-319, Berkeley, CA 94720 USA. NR 63 TC 112 Z9 113 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 JUN PY 2000 VL 61 IS 6 AR 064910 DI 10.1103/PhysRevC.61.064910 PG 13 WC Physics, Nuclear SC Physics GA 323PW UT WOS:000087575000069 ER PT J AU Yoshimoto, T Sato, T Arima, M Lee, TSH AF Yoshimoto, T Sato, T Arima, M Lee, TSH TI Dynamical test of constituent quark models with pi N reactions SO PHYSICAL REVIEW C LA English DT Article ID BARYON RESONANCES; NUCLEON INTERACTION; NONSTRANGE BARYONS; PARTICLE PHYSICS; PHOTOPRODUCTION; SCATTERING; AMPLITUDES; SPECTRUM; DECAYS; ELECTROPRODUCTION AB A dynamical approach is developed to predict the pi N scattering amplitudes starting with the constituent quark models. The first step is to apply a variational method to solve the three-quark bound state problem. The resulting wave functions are used to calculate the N*-->pi N, pi N, pi Delta vertex functions by assuming that the pi and eta mesons couple directly to quarks. These vertex functions and the predicted baryon bare masses then define a Hamiltonian for pi N reactions. We apply a unitary transformation method to derive from the constructed Hamiltonian a multichannel and multiresonance reaction model for predicting: the pi N scattering amplitudes up to W = 2 GeV. With the parameters constrained by the Delta(1232) excitation; we have examined the extent to which the pi N scattering in the S-11 channel can be described by constituent quark models based on one-gluon-exchange or one-meson exchange mechanisms. It is found that the data seem to favor the spin-spin interaction due to one-meson exchange and the tensor interaction due to one-gluon exchange. A phenomenological quark-quark potential has been constructed to reproduce the S-11 amplitude. C1 Osaka Univ, Dept Phys, Osaka 5600043, Japan. Osaka City Univ, Dept Phys, Osaka 5588585, Japan. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Yoshimoto, T (reprint author), Osaka Univ, Dept Phys, Osaka 5600043, Japan. NR 46 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 JUN PY 2000 VL 61 IS 6 AR 065203 DI 10.1103/PhysRevC.61.065203 PG 17 WC Physics, Nuclear SC Physics GA 323PW UT WOS:000087575000073 ER PT J AU Afanasev, AV Szczepaniak, AP AF Afanasev, AV Szczepaniak, AP TI Charge exchange rho(0)pi(+) photoproduction and implications for searches for exotic mesons SO PHYSICAL REVIEW D LA English DT Article ID HYBRID MESONS; CONSTITUENT GLUONS; LATTICE QCD; MODEL; EXCITATIONS; BAG AB We analyze the processes <(gamma)over right arrow>+p-->rho(o)pi(+)n at low momentum transfer focusing on the possibility of the production of an exotic J(PC) = 1(-+) meson state. In particular we discuss polarization observables and conclude that linear photon polarization is instrumental for separating the exotic wave. C1 N Carolina Cent Univ, Dept Phys, Durham, NC 27707 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Indiana Univ, Dept Phys, Bloomington, IN 47405 USA. Indiana Univ, Ctr Nucl Theory, Bloomington, IN 47405 USA. RP N Carolina Cent Univ, Dept Phys, Durham, NC 27707 USA. NR 29 TC 19 Z9 20 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 114008 DI 10.1103/PhysRevD.61.114008 PG 10 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800030 ER PT J AU Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lorenc, J Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, TK Briere, RA Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhao, X AF Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Kagan, H Kass, R Lorenc, J Schwarthoff, H von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Bishai, M Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Korolkov, I Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Dambasuren, E Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Titov, A Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Greene, R Perera, LP Zhou, GJ Chan, S Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Urheim, J Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Lange, DJ Morrison, RJ Nelson, TK Briere, RA Behrens, BH Ford, WT Gritsan, A Krieg, H Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Galik, RS Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lee, T Liu, Y Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Lohner, M Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Baringer, P Bean, A Besson, D Davis, R Kotov, S Kravchenko, I Kwak, N Zhao, X CA CLEO Collaboration TI Hadronic structure in the decay tau(-)->pi(-)pi(0)nu(tau) SO PHYSICAL REVIEW D LA English DT Article ID ELECTROWEAK RADIATIVE-CORRECTIONS; ALPHA(M-Z(2)) AB We report on a study of the invariant mass spectrum of the hadronic system in the decay tau(-) --> pi(-) pi(0) nu(tau). This study was performed with data obtained with the CLEO II detector operating at the CESR e(+)e(-) collider. We present fits to phenomenological models in which resonance parameters associated with the rho(770) and rho(1450) mesons are determined. The pi(-) pi(0) spectral function inferred from the invariant mass spectrum is compared with data on e(+)e(-) --> pi(+) pi(-) as a test of the conserved vector current theorem. We also discuss the implications of our data with regard to estimates of the hadronic contribution to the muon anomalous magnetic moment. C1 Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Ottawa, ON, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Texas Pan Amer, Edinburg, TX 78539 USA. Yonsei Univ, Seoul 120749, South Korea. Univ Cincinnati, Cincinnati, OH 45221 USA. RP Univ Minnesota, Minneapolis, MN 55455 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 17 TC 140 Z9 140 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 112002 DI 10.1103/PhysRevD.61.112002 PG 19 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800009 ER PT J AU Arkani-Hamed, N Hall, L Smith, D Weiner, N AF Arkani-Hamed, N Hall, L Smith, D Weiner, N TI Flavor at the TeV scale with extra dimensions SO PHYSICAL REVIEW D LA English DT Article ID QUANTUM-GRAVITY; MASS HIERARCHY; WEAK-SCALE; SUPERSYMMETRY; MILLIMETER AB Theories where the standard model fields reside on a 3-brane, with a low fundamental cutoff and extra dimensions, provide alternative solutions to the gauge hierarchy problem. However, generating flavor at the TeV scale while avoiding flavor-changing difficulties appears prohibitively difficult at first sight. We argue to the contrary that this picture allows us to lower flavor physics close to the TeV scale. Small Yukawa couplings are generated by ''shining'' badly broken flavor symmetries from distant branes, and flavor and CP-violating processes are adequately suppressed by these symmetries. We further show how the extra dimensions avoid four dimensional disasters associated with light fields charged under flavor. We construct elegant and realistic theories of flavor based on the maximal U(3)(5) flavor symmetry which naturally generate the simultaneous hierarchy of masses and mixing angles. Finally, we introduce a new framework for predictive theories of flavor, where our 3-brane is embedded within highly symmetrical configurations of higher-dimensional branes. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. RP Arkani-Hamed, N (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NR 26 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 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 116003 DI 10.1103/PhysRevD.61.116003 PG 21 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800072 ER PT J AU Arkani-Hamed, N Grossman, Y Schmaltz, M AF Arkani-Hamed, N Grossman, Y Schmaltz, M TI Split fermions in extra dimensions and exponentially small cross sections at future colliders SO PHYSICAL REVIEW D LA English DT Article ID SCALE QUANTUM-GRAVITY; STANDARD MODEL; TEV; COMPACTIFICATION; MILLIMETER; HIERARCHY AB We point out a dramatic new experimental signature for a class of theories with extra dimensions, where quarks and leptons are localized at slightly separated parallel "walls" whereas;gauge and Higgs fields Live in the bulk of the extra dimensions. The separation forbids direct local couplings between quarks and leptons, allowing for an elegant solution to the proton decay problem. We show that scattering cross sections for collisions of fermions which are separated in the extra dimensions vanish exponentially at energies high enough to probe the separation distance. This is because the separation puts a lower bound on the attainable impact parameter in the collision. We present cross sections for two body high energy scattering and estimate the power with which future colliders can probe this scenario, finding sensitivity to inverse fermion separations of order 10-70 TeV. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Arkani-Hamed, N (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. EM arkani@thsrv.lbl.gov; yuval@slac.stanford.edu; schmaltz@slac.stanford.edu NR 30 TC 81 Z9 81 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 115004 DI 10.1103/PhysRevD.61.115004 PG 8 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800065 ER PT J AU Atwood, D Bar-Shalom, S Soni, A AF Atwood, D Bar-Shalom, S Soni, A TI Graviton production by two photon and electron-photon processes in Kaluza-Klein theories with large extra dimensions SO PHYSICAL REVIEW D LA English DT Article ID LARGE COMPACT DIMENSIONS; HIGH-ENERGY COLLISIONS; SCALE QUANTUM-GRAVITY; GAMMA-GAMMA; COLLIDERS; TEV; CONSTRAINTS; SIGNALS; APPROXIMATION; MILLIMETER AB We consider the production of gravitons via two photon and electron-photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We show that at electron-positron colliders, the processes l(+)l(-) --> l(+)l(-)+ graviton, with l=e, mu, can lead to a new signal of low energy gravity of the form l(+)l(-) + missing energy which is well above the standard model background. For example, with two extra dimensions, at the Next Linear Collider with a center of mass energy of 500 or 1000 GeV, hundreds to thousands such l(+)l(-) + graviton events may be produced if the scale of the gravitational interactions, M-D, is around a few TeV. At a gamma-electron collider, more stringent bounds may be placed on M-D via the related reaction e(-)gamma-->e(-)G. For instance, if a 1 TeV e(+)e(-) collider is converted to an electron-photon collider, a bound of similar to 10(14) TeV may be placed on the scale M-D if the number of extra dimensions delta=2, while a bound of similar to 4(5) TeV may be placed if delta=4, with unpolarized (right polarized) electron beams. C1 Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Brookhaven Natl Lab, Theory Grp, Upton, NY 11973 USA. RP Atwood, D (reprint author), Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. EM atwood@iastate.edu; shaouly@phyun0.ucr.edu; soni@bnl.gov NR 41 TC 7 Z9 7 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 JUN 1 PY 2000 VL 61 IS 11 AR 116011 DI 10.1103/PhysRevD.61.116011 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800080 ER PT J AU Aurenche, P Gelis, F Zaraket, H AF Aurenche, P Gelis, F Zaraket, H TI Kinoshita-Lee-Nauenberg theorem, magnetic mass, and thermal photon production SO PHYSICAL REVIEW D LA English DT Article ID TEMPERATURE FIELD-THEORY; QUARK-GLUON PLASMA; FINITE-TEMPERATURE; GREEN-FUNCTIONS; REAL-TIME; COLLINEAR SINGULARITIES; GAUGE-THEORIES; CUTTING RULES; QCD; CANCELLATION AB We study the infrared singularities associated with ultrasoft transverse gluons in the calculation of photon production by a quark-gluon plasma. Despite the fact that the Kinoshita-Lee-Nauenberg theorem works in this context and provides cancellations of infrared singularities, it does not prevent the production rate of low invariant mass dileptons to be sensitive to the magnetic mass of gluons and therefore the rate to be nonperturbative. C1 Univ Savoie, CNRS, UMR 5108, Phys Theor Lab, F-74941 Annecy Le Vieux, France. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Univ Savoie, CNRS, UMR 5108, Phys Theor Lab, BP110, F-74941 Annecy Le Vieux, France. NR 34 TC 49 Z9 50 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 116001 DI 10.1103/PhysRevD.61.116001 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800070 ER PT J AU Batiz, Z Gross, F AF Batiz, Z Gross, F TI Gravitational coupling to two-particle bound states and momentum conservation in deep inelastic scattering SO PHYSICAL REVIEW D LA English DT Article AB The momentum conservation sum rule for deep inelastic scattering (DIS) from composite particles is investigated using the general theory of relativity. For two (1 + 1)-dimensional examples, it is shown that covariant theories automatically satisy the DIS momentum conservation sum rule provided the bound state is covariantly normalized. Therefore, in these cases the two DIS sum rules for baryon conservation and momentum conservation are equivalent. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23185 USA. Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RP Batiz, Z (reprint author), Coll William & Mary, Dept Phys, Williamsburg, VA 23185 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 114023 PG 12 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800045 ER PT J AU Bloch, JCR Roberts, CD Schmidt, SM AF Bloch, JCR Roberts, CD Schmidt, SM TI Memory effects and thermodynamics in strong field plasmas SO PHYSICAL REVIEW D LA English DT Article ID QUARK-GLUON PLASMA; NUCLEUS NUCLEUS COLLISIONS; HEAVY-ION COLLISIONS; PARTICLE-PRODUCTION; FINITE-TEMPERATURE; PAIR PRODUCTION; ELECTRIC-FIELD; EQUATION; MODEL; DYNAMICS AB We study the evolution of a strong field plasma using a quantum Vlasov equation with a non-Markovian source term and a simple collision term, and calculate the time dependence of the energy and number density, and the temperature. The evolution of a plasma produced with BNL RHIC-like initial conditions is well described by a low density approximation to the source term. However, non-Markovian aspects should be retained to obtain an accurate description of the early stages of a CERN LHC-like plasma. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 23 TC 23 Z9 24 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 117502 DI 10.1103/PhysRevD.61.117502 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800088 ER PT J AU Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Hill, TS Kutschke, R Lange, DJ Morrison, RJ Ryd, A Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J AF Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Hill, TS Kutschke, R Lange, DJ Morrison, RJ Ryd, A Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J CA CLEO Collaboration TI Measurement of the B-0 and B+ meson masses from B-0 ->psi((')) K-S(0) and B+->psi((')) K+ decays SO PHYSICAL REVIEW D LA English DT Article ID DETECTOR AB Using a sample of 9.6X 10(6)B (B) over bar meson pairs collected with the CLEO detector, we have fully reconstructed 135 B-0 --> psi(') K-S(0) and 526 B+ --> psi((')) K+ candidates with very low background. We fitted the psi((')) K invariant mass distributions of these B meson candidates and measured the masses of the neutral and charged B mesons to be M(B-0) = 5279.1 +/- 0.7[stat] +/- 0.3[syst] MeV/c(2) and M(B+) = 5279.1 +/- 0.4[stat] +/- 0.4[syst] MeV/c(2). The precision is a significant improvement over previous measurements. C1 Vanderbilt Univ, Nashville, TN 37232 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. Inst Particle Phys, Ottawa, ON, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Univ Cincinnati, Cincinnati, OH 45221 USA. MIT, Cambridge, MA 02139 USA. Univ Texas Pan Amer, Edinburg, TX 78539 USA. Yonsei Univ, Seoul 120749, South Korea. RP Csorna, SE (reprint author), Vanderbilt Univ, 221 Kirkland Hall, Nashville, TN 37232 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 7 TC 12 Z9 12 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 111101 DI 10.1103/PhysRevD.61.111101 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800001 ER PT J AU Isgur, N AF Isgur, N TI Comment on "Valence QCD: Connecting QCD to the quark model" SO PHYSICAL REVIEW D LA English DT Letter ID HADRON MASSES; HEAVY MESONS; LATTICE QCD; APPROXIMATION AB I criticize certain conclusions about the physics of hadrons drawn from a "valence QCD" approximation to QCD. C1 Jefferson Lab, Newport News, VA 23606 USA. RP Isgur, N (reprint author), Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA. NR 16 TC 20 Z9 20 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0556-2821 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 118501 DI 10.1103/PhysRevD.61.118501 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800093 ER PT J AU Jadach, S Placzek, W Skrzypek, M Ward, BFL Was, Z AF Jadach, S Placzek, W Skrzypek, M Ward, BFL Was, Z TI Final-state radiative effects for the exact O(alpha) Yennie-Frautschi-Suura exponentiated (un)stable W+W- production at and beyond CERN LEP2 energies SO PHYSICAL REVIEW D LA English DT Article ID W-PAIR PRODUCTION; MONTE-CARLO; UNSTABLE PARTICLES; GAUGE-INVARIANCE; CROSS-SECTION; ONE-LOOP; E+E-->W+W; FERMIONS; ANNIHILATION; RESONANCE AB We present the leading-logarithm (LL) final-state radiative effects for the exact O(alpha) YFS exponentiated (un)stable WW pair production at CERN LEP2 or NLC energies using Monte Carlo event generator methods. The corresponding event generator, version 1.12 of the program YFSWW3, wherein both standard model and anomalous triple gauge-boson couplings are allowed, generates n(gamma) radiation both from the initial state and from the intermediate W+ W- state, and generates the LL final state W decay radiative effects. Sample Monte Carlo data are given for illustration. C1 DESY, Div Theory, D-22603 Hamburg, Germany. Inst Nucl Phys, PL-30055 Krakow, Poland. CERN, Div Theory, CH-1211 Geneva, Switzerland. Jagiellonian Univ, Inst Comp Sci, PL-30072 Krakow, Poland. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Jadach, S (reprint author), DESY, Div Theory, D-22603 Hamburg, Germany. NR 27 TC 70 Z9 70 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 JUN 1 PY 2000 VL 61 IS 11 AR 113010 DI 10.1103/PhysRevD.61.113010 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800019 ER PT J AU Kharzeev, D Pisarski, RD AF Kharzeev, D Pisarski, RD TI Pionic measures of parity and CP violation in high energy nuclear collisions SO PHYSICAL REVIEW D LA English DT Article ID LARGE-N LIMIT; THETA-DEPENDENCE; DOMAIN-WALLS; CHIRAL DYNAMICS; CURRENT-ALGEBRA; GAUGE-THEORIES; HOT QCD; VACUUM; FIELD; GLUODYNAMICS AB The collisions of large nuclei at high energies could produce metastable vacua which are odd under parity P, charge conjugation C, and/or CP. Using only the three-momenta of charged pions (or kaons), we show how to construct global observables which are odd under P, C, and CP, and which can be measured on an event by event basis. Model dependent estimates of the P-odd observables are on the order of 10(-3). C1 Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Kharzeev, D (reprint author), Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. EM kharzeev@bnl.gov; pisarski@bnl.gov NR 41 TC 67 Z9 69 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 JUN 1 PY 2000 VL 61 IS 11 AR 111901 DI 10.1103/PhysRevD.61.111901 PG 4 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800007 ER PT J AU Liu, KF Dong, SJ Draper, T Sloan, J Wilcox, W Woloshyn, RM AF Liu, KF Dong, SJ Draper, T Sloan, J Wilcox, W Woloshyn, RM TI Reply to Isgur's comments on valence QCD SO PHYSICAL REVIEW D LA English DT Letter ID QUARK-MODEL; QUANTUM CHROMODYNAMICS; HADRON SPECTROSCOPY; CHIRAL THEORY; INSTANTONS; MESONS; NRQCD AB We reply to Isgur's critique that is directed at some of the conclusions drawn from the lattice simulation of valence QCD, regarding the valence quark model and effective chiral theories. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Spatial Technol, Boulder, CO 80301 USA. Baylor Univ, Dept Phys, Waco, TX 76798 USA. TRIUMF, Vancouver, BC V6T 2A3, Canada. RP Stanford Linear Accelerator Ctr, POB 4349, Stanford, CA 94309 USA. NR 28 TC 12 Z9 12 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 118502 DI 10.1103/PhysRevD.61.118502 PG 6 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800094 ER PT J AU Mirabelli, EA Schmaltz, M AF Mirabelli, EA Schmaltz, M TI Yukawa hierarchies from split fermions in extra dimensions SO PHYSICAL REVIEW D LA English DT Article ID KALUZA-KLEIN EXCITATIONS; ORBIFOLDS; MASSES; TESTS AB We explore a mechanism for generating the Yukawa hierarchies by displacing the left- and right-handed components of the standard model fermions in a higher-dimensional space. We find a unique configuration of displacements which fits all quark and lepton masses and mixing angles, with a prediction for the strange quark mass m(s)(<(MS)over bar>)(2 GeV) approximate to (1.19)x(VubVcb/V-us)(1/2)x m(b)(<(MS)over bar>)(m(b)) approximate to 120 MeV. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. EM gino@SLAC.stanford.edu; schmaltz@SLAG.stanford.edu NR 30 TC 138 Z9 138 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD JUN 1 PY 2000 VL 61 IS 11 AR 113011 DI 10.1103/PhysRevD.61.113011 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800020 ER PT J AU Silva, JP Soffer, A AF Silva, JP Soffer, A TI Impact of D-0-(D-0)over-bar mixing on the experimental determination of gamma SO PHYSICAL REVIEW D LA English DT Article ID CP VIOLATION; UNITARITY TRIANGLE; WEAK PHASE; ASYMMETRIES; PHYSICS; DECAYS; GAMMA AB Several methods have been devised to measure the weak phase gamma using decays of the type B+/- --> DK+/-, where it is assumed that there is no mixing in the DO-DO system. However, when using these methods to uncover new physics, one must entertain the real possibility that the measurements are affected by new physics effects in the D-0-<(D-0)over bar> system. We show that even values of x(D) and/or y(D) around 10(-2) can have a significant impact in the measurement of sin(2)gamma. We discuss the errors incurred in neglecting this effect, how the effect can be checked, and how to include it in the analysis. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Inst Super Engn Lisboa, P-1900 Lisbon, Portugal. RP Silva, JP (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RI Silva, Joao/A-2896-2009; Physics Department, ISEL/F-6664-2010 OI Silva, Joao/0000-0002-6455-9618; NR 29 TC 46 Z9 46 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 JUN 1 PY 2000 VL 61 IS 11 AR 112001 DI 10.1103/PhysRevD.61.112001 PG 14 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 318LE UT WOS:000087284800008 ER PT J AU Moldovan, D Golubovic, L AF Moldovan, D Golubovic, L TI Interfacial coarsening dynamics in epitaxial growth with slope selection SO PHYSICAL REVIEW E LA English DT Article ID MOLECULAR-BEAM EPITAXY; BUCKLING DYNAMICS; ORDERING DYNAMICS; HOMOEPITAXY; FILMS; INSTABILITY; TRANSITION; MORPHOLOGY; CONTINUUM; MEMBRANES AB We investigate interfacial dynamics of molecular-beam epitaxy (MBE) growth in the presence of instabilities inducing formation of pyramids. We introduce a kinetic scaling theory which provides an analytic understanding of the coarsening dynamics laws observed in numerous experiments and simulations of the MBE. We address MBE growth on crystalline surfaces with different symmetries in order to explain experimentally observed differences between the growth on (111) and (001) surfaces and understand the coarsening exponents measured on these surfaces. We supplement our kinetic scaling theory by numerical simulations which document that the edges of the pyramids, forming a network across the growing interface, are essential for qualitative understanding of the coarsening dynamics of molecular-beam epitaxy. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. RP Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 33 TC 71 Z9 71 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD JUN PY 2000 VL 61 IS 6 BP 6190 EP 6214 DI 10.1103/PhysRevE.61.6190 PN A PG 25 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 323PZ UT WOS:000087575300025 ER PT J AU Hagberg, A Meron, E Passot, T AF Hagberg, A Meron, E Passot, T TI Phase dynamics of nearly stationary patterns in activator-inhibitor systems SO PHYSICAL REVIEW E LA English DT Article ID REACTION-DIFFUSION SYSTEMS; EXCITABLE MEDIA; TURING PATTERNS; TRAVELING WAVES; FRONTS; BIFURCATIONS; EQUILIBRIUM; 2-COMPONENT; DOMAINS; SPOTS AB The slow dynamics of nearly stationary patterns in a FitzHugh-Nagumo model are studied using a phase dynamics approach. A Cross-Newell phase equation describing slow and weak modulations of periodic stationary solutions is derived. The derivation applies to the bistable, excitable, and Turing unstable regimes. In the bistable case stability thresholds are obtained for the Eckhaus and zigzag instabilities and for the transition to traveling waves. Neutral stability curves demonstrate the destabilization of stationary planar patterns at low wave numbers to zigzag and traveling modes. Numerical solutions of the model system support the theoretical findings. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. Ben Gurion Univ Negev, Jacob Blaustein Inst Desert Res, IL-84990 Sede Boqer, Israel. Ben Gurion Univ Negev, Dept Phys, IL-84990 Sede Boqer, Israel. Observ Cote Azur, F-06034 Nice 4, France. Univ Arizona, Dept Math, Tucson, AZ 85721 USA. RP Hagberg, A (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RI MERON, EHUD/F-1810-2012 NR 33 TC 7 Z9 7 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD JUN PY 2000 VL 61 IS 6 BP 6471 EP 6476 DI 10.1103/PhysRevE.61.6471 PN A PG 6 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 323PZ UT WOS:000087575300057 ER PT J AU Inokuti, M Rau, ARP AF Inokuti, M Rau, ARP TI Special issue - In honor of Ugo Fano SO PHYSICS ESSAYS LA English DT Editorial Material C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Inokuti, M (reprint author), Argonne Natl Lab, Argonne, IL 60439 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PHYSICS ESSAYS PUBLICATION PI HULL PA C/O ALFT INC, 189 DEVEAULT ST, UNIT NO. 7, HULL, PQ J8Z1S7, CANADA SN 0836-1398 J9 PHYS ESSAYS JI Phys. Essays PD JUN-SEP PY 2000 VL 13 IS 2-3 SI SI BP 156 EP 157 PG 2 WC Physics, Multidisciplinary SC Physics GA 428YT UT WOS:000168489800002 ER PT J AU Berkowitz, J AF Berkowitz, J TI The quantum yield of ionization SO PHYSICS ESSAYS LA English DT Article DE superexcited states; resonant autoionization; direct ionization; electronic autoionization; predissociation; vibrational autoionization; radiationless transition; quantum yield ID PHOTOIONIZATION CROSS-SECTIONS; 2-DIMENSIONAL PHOTOELECTRON-SPECTROSCOPY; RYDBERG STATES; DISSOCIATIVE PHOTOIONIZATION; ELECTRONIC AUTOIONIZATION; BRANCHING RATIOS; VIBRATIONAL AUTOIONIZATION; NEUTRAL-DISSOCIATION; RADIATIVE EMISSION; TOTAL ABSORPTION AB The mechanisms by which "superexcited" states decay are summarized. Experimental studies aimed at deducing these mechanisms for diatomic, triatomic, and polyatomic molecules are reviewed and examined for patterns. From this analysis, dominant mechanisms are identified. Thereupon, an explanation is offered for the observation that the quantum yield of ionization approaches unity at similar to 20 eV, regardless of molecular size. A concomitant conclusion is that large molecules should ionize effectively, contrary to a recent conjecture. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. EM berkowitz@anl.gov NR 78 TC 15 Z9 15 U1 2 U2 6 PU PHYSICS ESSAYS PUBLICATION PI OTTAWA PA PO BOX 8141 STATION T, OTTAWA, ONTARIO K1G 3H6, CANADA SN 0836-1398 J9 PHYS ESSAYS JI Phys. Essays PD JUN-SEP PY 2000 VL 13 IS 2-3 SI SI BP 248 EP 255 PG 8 WC Physics, Multidisciplinary SC Physics GA 428YT UT WOS:000168489800010 ER PT J AU Southworth, SH Ferrett, TA Hardis, JE Parr, AC Dehmer, JL AF Southworth, SH Ferrett, TA Hardis, JE Parr, AC Dehmer, JL TI Valence-shell autoionization of NO SO PHYSICS ESSAYS LA English DT Article DE molecular autoionization; photoelectron spectroscopy; synchrotron radiation ID QUANTUM-DEFECT-THEORY; IONIZATION CROSS-SECTIONS; BRANCHING RATIOS; NITRIC-OXIDE; MOLECULAR PHOTOIONIZATION; ANGULAR-DISTRIBUTIONS; SPECTROMETER SYSTEM; REGION; PHOTODISSOCIATION; PHOTOELECTRONS AB Autoionization of valence and Rydberg states in NO over the 12.5--18 eV photon energy range was studied by vibrationally resolved photoelectron spectroscopy of the 2 pi orbital. Complex, oscillatory structure is observed in NO+ (2 pi (-1)) X(1)Sigma (+) partial cross sections, branching ratios, and photoelectron anisotropy parameters due to autoionizing valence states and Rydberg slates associated with the 1 pi (-1) and 5 sigma (-1) channels. Autoionization of the 5 sigma --> np(pi, sigma) (v' = 0), n = 3-5 Rydberg states leading to the (5 sigma (-1)) b(3) IIstate of NO+ produces very high vibrational levels of (2 n(-1)) X(1)Sigma (+). Autoionization of the 5 sigma --> 3p pi (v' = 0) Rydberg C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Southworth, SH (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 55 TC 2 Z9 2 U1 1 U2 6 PU PHYSICS ESSAYS PUBLICATION PI HULL PA C/O ALFT INC, 189 DEVEAULT ST, UNIT NO. 7, HULL, PQ J8Z1S7, CANADA SN 0836-1398 J9 PHYS ESSAYS JI Phys. Essays PD JUN-SEP PY 2000 VL 13 IS 2-3 SI SI BP 290 EP 296 PG 7 WC Physics, Multidisciplinary SC Physics GA 428YT UT WOS:000168489800015 ER PT J AU Smith, DY Inokuti, M Karstens, W AF Smith, DY Inokuti, M Karstens, W TI Photoresponse of condensed matter over the entire range of excitation energies: Analysis of silicon SO PHYSICS ESSAYS LA English DT Article DE photoresponse; optical properties; refractive index; dispersion relations; Kramers-Kronig relations; sum rules; silicon; semiconductors ID X-RAY REGION; OPTICAL-CONSTANTS; REFRACTIVE-INDEX; SUM-RULES; SUPERCONVERGENCE; GERMANIUM; SI AB Methods for the analysis of experimental data to determine the photoresponse of condensed-matter systems over the entire spectral range are considered in light of sum-rule constraints imposed by quantum mechanics, causality, and linear-response theory. We outline an extension to elemental semiconductors of the self-consistent Kramers-Kronig method for constructing composite sets of optical constants developed in the 1980s for metals. Several new sum rules relating the refractive index at infrared wavelengths to moments of the absorption spectrum are derived and illustrated for silicon. C1 Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Smith, DY (reprint author), Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. NR 40 TC 5 Z9 5 U1 0 U2 0 PU PHYSICS ESSAYS PUBLICATION PI HULL PA C/O ALFT INC, 189 DEVEAULT ST, UNIT NO. 7, HULL, PQ J8Z1S7, CANADA SN 0836-1398 J9 PHYS ESSAYS JI Phys. Essays PD JUN-SEP PY 2000 VL 13 IS 2-3 SI SI BP 465 EP 472 PG 8 WC Physics, Multidisciplinary SC Physics GA 428YT UT WOS:000168489800038 ER PT J AU Melnikov, K van Ritbergen, T AF Melnikov, K van Ritbergen, T TI The three-loop relation between the (MS)over-bar and the pole quark masses SO PHYSICS LETTERS B LA English DT Article ID HEAVY-QUARK; QUANTUM CHROMODYNAMICS; PERTURBATION-THEORY; ORDER ALPHA(3)(S); STATIC QUARK; QCD; RESUMMATION; DECAYS AB The analytic I elation between the MS and the pole quark masses is computed to O(alpha(s)(3)) in QCD. Using this exact result, the accuracy of the large beta(0) approximation is critically examined and the implications of the obtained relation for semileptonic B decays are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Karlsruhe, Inst Theoret Teilchenphys, D-76128 Karlsruhe, Germany. RP Melnikov, K (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 41 TC 260 Z9 260 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 JUN 1 PY 2000 VL 482 IS 1-3 BP 99 EP 108 DI 10.1016/S0370-2693(00)00507-4 PG 10 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 322PX UT WOS:000087518900013 ER PT J AU Avignone, FT Anderso, BD Awes, TC Berridge, S Bilpuch, W Britton, C Bryan, W Bugg, WM Burman, RL Busenitz, J Carter, K Chatterjee, L Cianciolo, V Cochran, AK Cohn, HO Danilov, MV De-Brackeleer, L Degtiarenko, P Efremenko, YV Elaasar, MA Fazely, AR Frank, S Gabriel, TA Gould, CR Gudkov, V Gunasingha, R Handler, T Hart, EL Imlay, RL Jagadish, U Kamyshkov, YA Khosrovi, E Koetke, DD Lane, C Manweiler, RW Metcalf, WJ Mezzacappa, A Mo, LW Nosik, VZ Nummaker, TA Nussinov, S Piepke, A Plasil, F Reidy, J Rosenfeld, C Smith, D Stancu, I Stanislaus, TDS Steinberg, R Svoboda, R Tashakkori, R Tornow, W Van Dalen, G Walker, J Watson, JW Wintenberg, A Wolf, J Wright, DH Zeldovich, OY Zhang, WM AF Avignone, FT Anderso, BD Awes, TC Berridge, S Bilpuch, W Britton, C Bryan, W Bugg, WM Burman, RL Busenitz, J Carter, K Chatterjee, L Cianciolo, V Cochran, AK Cohn, HO Danilov, MV De-Brackeleer, L Degtiarenko, P Efremenko, YV Elaasar, MA Fazely, AR Frank, S Gabriel, TA Gould, CR Gudkov, V Gunasingha, R Handler, T Hart, EL Imlay, RL Jagadish, U Kamyshkov, YA Khosrovi, E Koetke, DD Lane, C Manweiler, RW Metcalf, WJ Mezzacappa, A Mo, LW Nosik, VZ Nummaker, TA Nussinov, S Piepke, A Plasil, F Reidy, J Rosenfeld, C Smith, D Stancu, I Stanislaus, TDS Steinberg, R Svoboda, R Tashakkori, R Tornow, W Van Dalen, G Walker, J Watson, JW Wintenberg, A Wolf, J Wright, DH Zeldovich, OY Zhang, WM TI ORLaND: A proposed neutrino facility at the Oak Ridge National Laboratory SO PHYSICS OF ATOMIC NUCLEI LA English DT Article; Proceedings Paper CT 2nd International Conference on Nonaccelerator New Physics (NANP 99) CY JUN 28-JUL 03, 1999 CL DUBNA, RUSSIA SP Joint Inst Nuclear Res, Russian Fdn Basic res, Russian Acad Sci, Inst Nuclear Res, Czech Tech Univ, Prague AB Oak Ridge National Laboratory, Tennessee, USA, ORLaND is a collaboration proposing a major neutrino physics facility at the Spallation Neutrino Source (SNS) at the Oak Ridge National Laboratory. An underground bunker is proposed adjacent to the first target station of the SNS. The bunker is designed to house one large detector (2000 t) and a number of smaller (200 t) detectors. A comprehensive program of neutrino experiments is being developed that could span the lifetime of the Spallation Source. (C) 2000 MAIK "Nauka/Interperiodica". C1 Oak Ridge Natl Lab, Oak Ridge, TN USA. RP Avignone, FT (reprint author), Univ S Carolina, Columbia, SC 29208 USA. RI Gould, Christopher/M-7676-2013; Danilov, Mikhail/C-5380-2014; Kamyshkov, Yuri/J-7999-2016; Mezzacappa, Anthony/B-3163-2017 OI Danilov, Mikhail/0000-0001-9227-5164; Kamyshkov, Yuri/0000-0002-3789-7152; Mezzacappa, Anthony/0000-0001-9816-9741 NR 8 TC 14 Z9 14 U1 0 U2 3 PU MAIK NAUKA/INTERPERIODICA PUBL PI MELVILLE PA C/O AMERICAN INST PHYSICS, 2 HUNTINGTON QUANDRANGLE, STE 1NO1, MELVILLE, NY 11747-4502 USA SN 1063-7788 J9 PHYS ATOM NUCL+ JI Phys. Atom. Nuclei PD JUN PY 2000 VL 63 IS 6 BP 1007 EP 1011 DI 10.1134/1.855740 PG 5 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 336BL UT WOS:000088282000013 ER PT J AU van Doorn, E Dhruva, B Sreenivasan, KR Cassella, V AF van Doorn, E Dhruva, B Sreenivasan, KR Cassella, V TI Statistics of wind direction and its increments SO PHYSICS OF FLUIDS LA English DT Article ID TURBULENCE AB We study some elementary statistics of wind direction fluctuations in the atmosphere for a wide range of time scales (10(-4) sec to 1 h), and in both vertical and horizontal planes. In the plane parallel to the ground surface, the direction time series consists of two parts: a constant drift due to large weather systems moving with the mean wind speed, and fluctuations about this drift. The statistics of the direction fluctuations show a rough similarity to Brownian motion but depend, in detail, on the wind speed. This dependence manifests itself quite clearly in the statistics of wind-direction increments over various intervals of time. These increments are intermittent during periods of low wind speeds but Gaussian-like during periods of high wind speeds. (C) 2000 American Institute of Physics. [S1070-6631(00)02506-X]. C1 Yale Univ, Mason Lab, New Haven, CT 06520 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP van Doorn, E (reprint author), Yale Univ, Mason Lab, New Haven, CT 06520 USA. NR 10 TC 34 Z9 34 U1 2 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD JUN PY 2000 VL 12 IS 6 BP 1529 EP 1534 DI 10.1063/1.870401 PG 6 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 310KE UT WOS:000086826000022 ER PT J AU Dimonte, G AF Dimonte, G TI Spanwise homogeneous buoyancy-drag model for Rayleigh-Taylor mixing and experimental evaluation SO PHYSICS OF PLASMAS LA English DT Article ID RICHTMYER-MESHKOV INSTABILITY; RADIATIVELY DRIVEN SHOCKS; VARIABLE ACCELERATION; NUMERICAL-SIMULATION; NONLINEAR EVOLUTION; COMPRESSIBLE FLUIDS; BUBBLE MERGER; INTERFACES; FRONTS; LASER AB A buoyancy-drag model for Rayleigh-Taylor (RT) mixing is developed on the premise that the bubble and spike regions behave as distinct and spanwise homogeneous fluids. Then, mass conservation is applied accross the mixing zone to obtain their average mixture densities dynamically. These are used to explicitly calculate the inertia and buoyancy terms in the evolutionary equation. The only unknown parameter in the model is the Newtonian drag constant C similar to 2.5 +/- 0.6, which is determined from turbulent RT experiments over various Atwood numbers A and acceleration histories g(t). The bubble (i = 2) and spike (i = 1) amplitudes are found to obey the familiar h(i) = alpha(i)Agt(2) for a constant g and h(i)similar to t(i)(theta) for an impulsive g. For bubbles, both alpha(2) and theta(2) are insensitive to A. For the spikes, both alpha(1) and theta(1) increase as a power law with the density ratio. However, theta(1) is not universal because it depends on the initial value of h(1)/h(2). (C) 2000 American Institute of Physics. [S1070-664X(00)01705-5]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Dimonte, G (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. NR 57 TC 81 Z9 83 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2255 EP 2269 DI 10.1063/1.874060 PG 15 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500001 ER PT J AU Kruer, WL AF Kruer, WL TI Interaction of plasmas with intense lasers SO PHYSICS OF PLASMAS LA English DT Article ID STIMULATED RAMAN-SCATTERING; DRIVEN PARAMETRIC-INSTABILITIES; INERTIAL CONFINEMENT FUSION; HOHLRAUM PLASMAS; BEAM DEFLECTION; SATURATION; LANGMUIR; PARTICLE; LIGHT; FLOW AB The interaction of plasmas with intense lasers is an excellent example of how different fields of physics are interconnected. Invention of the laser and its ongoing development has allowed the creation and study of high temperature, dense matter in the laboratory. The results both advance the underlying plasma science and are relevant to many fields ranging from astrophysics to fusion and nonlinear physics. A brief overview of the interaction physics is given. Selected topics are discussed to illustrate the exciting progress in experimental, theoretical, and computational investigations with focused laser intensities up to 10(21) W/cm(2). (C) 2000 American Institute of Physics. [S1070-664X(00)01805-X]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. USN, Postgrad Sch, Monterey, CA 93943 USA. RP Kruer, WL (reprint author), USN, Postgrad Sch, Monterey, CA 93943 USA. NR 48 TC 39 Z9 41 U1 1 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2270 EP 2278 AR PII [S1070-664X(00)01805-X] DI 10.1063/1.874061 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500002 ER PT J AU Myra, JR D'Ippolito, DA Xu, XQ Cohen, RH AF Myra, JR D'Ippolito, DA Xu, XQ Cohen, RH TI Resistive X-point modes in tokamak boundary plasmas SO PHYSICS OF PLASMAS LA English DT Article ID SCRAPE-OFF LAYER; BALLOONING STABILITY; DIVERTOR TOKAMAKS; MAGNETIC-FIELD; H-MODE; EQUILIBRIUM; SEPARATRIX; TURBULENCE; INSTABILITY; TRANSPORT AB It is shown that the boundary (edge and scrape-off-layer) plasma in a typical low (L) mode diverted tokamak discharge is unstable to a new class of modes called resistive X-point (RX) modes. The RX mode is a type of resistive ballooning mode that exploits a synergism between resistivity and the magnetic geometry of the X-point region. The RX modes are shown to give robust instabilities at moderate mode numbers, and therefore are expected to be the dominant contributors to turbulent diffusion in the boundary plasma of a diverted tokamak. (C) 2000 American Institute of Physics. [S1070-664X(00)03206-7]. C1 Lodestar Res Corp, Boulder, CO 80301 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Myra, JR (reprint author), Lodestar Res Corp, 2400 Cent Ave, Boulder, CO 80301 USA. NR 25 TC 20 Z9 20 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2290 EP 2293 DI 10.1063/1.874125 PG 4 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500004 ER PT J AU Lemons, DS Murillo, MS Daughton, W Winske, D AF Lemons, DS Murillo, MS Daughton, W Winske, D TI Two-dimensional wake potentials in sub- and supersonic dusty plasmas SO PHYSICS OF PLASMAS LA English DT Article ID 3-DIMENSIONAL STRUCTURE; ATTRACTIVE FORCES; CRYSTAL-FORMATION; ION FLOW; PARTICLES AB Hot electrons and sub- and supersonic flows of cold ions around a charged dust particle create steady state wake and Debye screening fields. These linear, electrostatic fields are studied in two-dimensional planar or cylindrical geometry. An asymptotic analysis in the limit of large (compared to Debye length) downstream coordinate z yields analytic wakefields that are in good agreement with numerical integrations of the linear, steady state response function. (C) 2000 American Institute of Physics. [S1070-664X(00)01406-3]. C1 Bethel Coll, N Newton, KS 67117 USA. Univ Calif Los Alamos Natl Lab, Div Appl Phys, Los Alamos, NM 87545 USA. RP Lemons, DS (reprint author), Univ Calif Los Alamos Natl Lab, Div Appl Phys, POB 1663, Los Alamos, NM 87545 USA. RI Daughton, William/L-9661-2013 NR 24 TC 48 Z9 48 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2306 EP 2313 DI 10.1063/1.874065 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500008 ER PT J AU Winske, D Daughton, W Lemons, DS Murillo, MS AF Winske, D Daughton, W Lemons, DS Murillo, MS TI Ion kinetic effects on the wake potential behind a dust grain in a flowing plasma SO PHYSICS OF PLASMAS LA English DT Article ID CRYSTAL-FORMATION; COULOMB CRYSTALS; PARTICLE; SIMULATION; INSTABILITY; DISCHARGES; LATTICE; SHEATH; WAVES AB The structure of the wake potential downstream of a stationary dust grain in a flowing plasma is studied on ion time scales using particle-in-cell simulation methods. The scaling of the wake is investigated as a function of Mach number and other parameters as well as the dimensionality of the system. The results are compared and discussed in relation to various theoretical expressions for the wake. Consistent with theory, in one dimension the wake wavelength scales as M lambda(De)(1-M-2)(-1/2) for M < 1, where M is the Mach number and lambda(De) is the electron Debye length, while no wake forms for M > 1. In two dimensions, a wake is formed for both M < 1 and M > 1, while the wake wavelength scales as M lambda(De) in both regimes. The amplitude of the wake peaks at M approximate to 1 in both the one- and two-dimensional simulations. (C) 2000 American Institute of Physics. [S1070-664X(00)02006-1]. C1 Los Alamos Natl Lab, Div Appl Phys, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Div Appl Phys, POB 1663, Los Alamos, NM 87545 USA. RI Daughton, William/L-9661-2013 NR 38 TC 52 Z9 52 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2320 EP 2328 AR PII [S1070-664X(00)02006-1] DI 10.1063/1.874067 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500010 ER PT J AU Redi, MH Diallo, A Cooper, WA Fu, GY Nuhrenberg, C Pomphrey, N Reiman, AH Zarnstorff, MC AF Redi, MH Diallo, A Cooper, WA Fu, GY Nuhrenberg, C Pomphrey, N Reiman, AH Zarnstorff, MC CA NCSX Team TI Robustness and flexibility in compact quasiaxial stellarators: Global ideal magnetohydrodynamic stability and energetic particle transport SO PHYSICS OF PLASMAS LA English DT Article ID N MAGNETIC PERTURBATIONS; ALPHA-PARTICLES; TOKAMAK; TFTR; IONS; MODES AB Concerns about the flexibility and robustness of a compact quasiaxial stellarator design are addressed by studying the effects of varied pressure and rotational transform profiles on expected performance. For thirty, related, fully three-dimensional configurations the global, ideal magnetohydrodynamic (MHD) stability and energetic particle transport are evaluated. It is found that tokamak intuition is relevant to understanding the magnetohydrodynamic stability, with pressure gradient driving terms and shear stabilization controlling both the periodicity preserving, N=0, and the nonperiodicity preserving, N=1, unstable kink modes. Global kink modes are generated by steeply peaked pressure profiles near the half radius and edge localized kink modes are found for plasmas with steep pressure profiles at the edge as well as with edge rotational transform above 0.5. Energetic particle transport is not strongly dependent on these changes of pressure and current (or rotational transform) profiles, although a weak inverse dependence on pressure peaking through the corresponding Shafranov shift is found. While good transport and MHD stability are not anticorrelated in these equilibria, stability only results from a delicate balance of the pressure and shear stabilization forces. A range of interesting MHD behaviors is found for this large set of equilibria, exhibiting similar particle transport properties. (C) 2000 American Institute of Physics. [S1070-664X(00)03606-5]. C1 Princeton Univ, Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Montana, Missoula, MT 59801 USA. Ctr Rech Phys Plasmas, Lausanne, Switzerland. Max Planck Inst Plasma Phys, Greifswald, Germany. RP Princeton Univ, Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. EM redi@pppl.gov RI pomphrey, neil/G-4405-2010; Diallo, Ahmed/M-7792-2013 NR 26 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 1070-664X EI 1089-7674 J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2508 EP 2516 AR PII [S1070-664X(00)03606-5] DI 10.1063/1.874090 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500033 ER PT J AU Cohen, SA Milroy, RD AF Cohen, SA Milroy, RD TI Maintaining the closed magnetic-field-line topology of a field-reversed configuration with the addition of static transverse magnetic fields SO PHYSICS OF PLASMAS LA English DT Article ID ROTAMAK AB The effects on magnetic-field-line structure of adding various static transverse magnetic fields to a Solov'ev-equilibrium field-reversed configuration are examined. It is shown that adding fields that are antisymmetric about the axial midplane maintains the closed field-line structure, while adding fields with planar or helical symmetry opens the field structure. Antisymmetric modes also introduce pronounced shear. (C) 2000 American Institute of Physics. [S1070-664X(00)03705-8]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. Univ Washington, Redmond Plasma Phys Lab, Redmond, WA 98052 USA. RP Cohen, SA (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 15 TC 33 Z9 33 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2539 EP 2545 DI 10.1063/1.874094 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500037 ER PT J AU Brooks, JN Naujoks, D AF Brooks, JN Naujoks, D TI Sheath superheat transmission due to redeposition of thermally emitted material SO PHYSICS OF PLASMAS LA English DT Article ID OPERATION AB A self-consistent three-dimensional numerical analysis using the newly developed BPHI-3D code was performed for the Debye/magnetic tokamak-type oblique incidence magnetic field sheath, with near-surface ionization and transport of thermally emitted surface material. The analysis uses Monte Carlo, kinetic treatment for deuterium-tritium and impurity ions/neutrals, Boltzmann/guiding-center electrons, and particle-in-cell time-independent Poisson solver. For typical predicted fusion edge plasma conditions for a liquid lithium divertor most evaporated lithium atoms-from a similar to 1 cm(2) overheated spot-are ionized in the similar to 1 mm-wide magnetic sheath. These ions are strongly redeposited due to the sheath electric field. While this redeposition minimizes core plasma contamination, it increases the peak heat flux to the surface. A runaway situation is then possible due to superheating/evaporation positive feedback. Carbon may behave likewise as seen in code results obtained for a TORE SUPRA [Aymar , Plasma Physics and Controlled Nuclear Fusion Research (IAEA, Vienna, 1989)] carbon limiter. A semianalytic formula for sheath parameters as a function of emitted surface material flux is developed and verified with the code. (C) 2000 American Institute of Physics. [S1070-664X(00)05206-X]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Max Planck Inst Plasmaphys, Berlin, Germany. RP Brooks, JN (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 19 Z9 19 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2565 EP 2570 DI 10.1063/1.874097 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500040 ER PT J AU Rose, HA AF Rose, HA TI Langmuir wave turbulence transition in a model of stimulated Raman scatter SO PHYSICS OF PLASMAS LA English DT Article ID MODIFIED DECAY REGIME; CYLINDRICAL HOT-SPOT; PARAMETRIC-INSTABILITIES; BACKSCATTERING INSTABILITIES; INHOMOGENEOUS-PLASMA; TEMPORAL BEHAVIOR; TIME BEHAVIOR; SPACE AB In a one-dimensional stationary slab model, it is found that once the stimulated Raman scatter (SRS) homogeneous growth rate, gamma(0), exceeds a threshold value, gamma(T), there exists a local, finite amplitude instability, which leads to Langmuir wave turbulence (LWT). Given energetic enough initial conditions, this allows forward SRS, a linearly convective instability, to be nonlinearly self-sustaining for gamma(0)>gamma(T). Levels of forward scatter, much larger than predicted by the linear amplification of thermal fluctuations, are then accessible. The Stochastic quasilinear Markovian (SQM) model of SRS interacting with LWT predicts a jump in the value of [epsilon], the mean energy injection rate from the laser to the plasma, across this threshold, while one-dimensional plasma slab simulations reveal large fluctuations in epsilon, and a smooth variation of [epsilon] with gamma(0). Away from gamma(T), [epsilon] is well predicted by the SQM. If a background density ramp is imposed, LWT may lead to loss of SRS gradient stabilization for gamma(0)much less than gamma(T). (C) 2000 American Institute of Physics. [S1070-664X(00)00906-X]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Rose, HA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 24 TC 5 Z9 5 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2571 EP 2577 DI 10.1063/1.874098 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500041 ER PT J AU Li, CK Hicks, DG Seguin, FH Frenje, JA Petrasso, RD Soures, JM Radha, PB Glebov, VY Stoeckl, C Harding, DR Knauer, JP Kremens, R Marshall, FJ Meyerhofer, DD Skupsky, S Roberts, S Sorce, C Sangster, TC Phillips, TW Cable, MD Leeper, RJ AF Li, CK Hicks, DG Seguin, FH Frenje, JA Petrasso, RD Soures, JM Radha, PB Glebov, VY Stoeckl, C Harding, DR Knauer, JP Kremens, R Marshall, FJ Meyerhofer, DD Skupsky, S Roberts, S Sorce, C Sangster, TC Phillips, TW Cable, MD Leeper, RJ TI D-He-3 proton spectra for diagnosing shell rho R and fuel T-i of imploded capsules at OMEGA SO PHYSICS OF PLASMAS LA English DT Article ID NATIONAL-IGNITION-FACILITY; INERTIAL CONFINEMENT FUSION; DETECTOR; PLASMAS AB Recent work has resulted in the first high-resolution, spectroscopic measurements of energetic charged particles on OMEGA laser facility [T. R. Boehly , Opt. Commun. 133, 496 (1997)]. Energy spectra of charged fusion products have been obtained from two spectrometers, and have been used to deduce various physical quantities in imploded capsules. In this paper the first use of 14.7 MeV deuterium-helium3 (D-He-3) proton spectra for diagnosing shell areal density (rho R) and fuel ion temperature (T-i) is discussed. For thick-plastic shell capsules, shell areal densities between 20 and 70 mg/cm(2) and ion temperatures between 3 and 5 keV have been determined. The spectral linewidths associated with such capsules are found to be wider than the doppler widths. This effect, the focus of future study, is the result of rho R evolution during the burn; or is the result of an extended burn region; or results from nonuniformities in the shell. For thin-glass shell capsules, the spectral linewidths are dominated by the doppler width, and ion temperatures between 10 and 15 keV were determined. These measurements have been also compared and contrasted with the results from neutron measurements and from one-dimension hydrodynamic simulations. (C) 2000 American Institute of Physics. [S1070-664X(00)01306-9]. C1 MIT, Plasma Sci & Fus Ctr, Cambridge, MA 02139 USA. Univ Rochester, Laser Energet Lab, Rochester, NY 14623 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Li, CK (reprint author), MIT, Plasma Sci & Fus Ctr, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Hicks, Damien/B-5042-2015 OI Hicks, Damien/0000-0001-8322-9983 NR 25 TC 49 Z9 50 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2578 EP 2584 AR PII [S1070-664X(00)01306-9] DI 10.1063/1.874099 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500042 ER PT J AU Glenzer, SH Suter, LJ Berger, RL Estabrook, KG Hammel, BA Kauffman, RL Kirkwood, RK MacGowan, BJ Moody, JD Rothenberg, JE Turner, RE AF Glenzer, SH Suter, LJ Berger, RL Estabrook, KG Hammel, BA Kauffman, RL Kirkwood, RK MacGowan, BJ Moody, JD Rothenberg, JE Turner, RE TI Hohlraum energetics with smoothed laser beams SO PHYSICS OF PLASMAS LA English DT Article ID INERTIAL-CONFINEMENT-FUSION; SCALE-LENGTH PLASMAS; STIMULATED BRILLOUIN-SCATTERING; NATIONAL-IGNITION-FACILITY; EXPLODING FOIL PLASMAS; X-RAY CONFINEMENT; THOMSON SCATTERING; INDIRECTLY DRIVEN; RAMAN-SCATTERING; RADIATION DRIVE AB Measurements of radiation temperatures from empty and gas-filled hohlraums heated at the Nova Laser Facility [E. M. Campbell , Laser Part. Beams 9, 209 (1991)] show efficient coupling of the laser power to the target when applying laser beam smoothing techniques. Scattering losses are reduced to the 3% level while the radiation temperatures increased by similar to 15 eV for smoothed laser beams. The experimental findings and supporting calculations indicate that filamentation and gain for stimulated Raman and Brillouin scattering is suppressed in the hohlraum plasma for smoothed laser beams. The scaling of the radiation temperature is well described by integrated radiation hydrodynamic LASNEX modeling [G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Controlled Fusion 2, 85 (1975)] following the Marshak scaling. Peak radiation temperatures are in excess of 230 eV in gas-filled hohlraums in agreement with the detailed LASNEX modeling. (C) 2000 American Institute of Physics. [S1070-664X(00)03505-9]. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Glenzer, SH (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-437,POB 808, Livermore, CA 94551 USA. NR 59 TC 18 Z9 22 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2585 EP 2593 DI 10.1063/1.874100 PG 9 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500043 ER PT J AU Bennett, GR Wallace, JM Murphy, TJ Chrien, RE Delamater, ND Gobby, PL Hauer, AA Klare, KA Oertel, JA Watt, RG Wilson, DC Varnum, WS Craxton, RS Glebov, VY Schnittman, JD Stoeckl, C Pollaine, SM Turner, RE AF Bennett, GR Wallace, JM Murphy, TJ Chrien, RE Delamater, ND Gobby, PL Hauer, AA Klare, KA Oertel, JA Watt, RG Wilson, DC Varnum, WS Craxton, RS Glebov, VY Schnittman, JD Stoeckl, C Pollaine, SM Turner, RE TI Moderate-convergence inertial confinement fusion implosions in tetrahedral hohlraums at Omega SO PHYSICS OF PLASMAS LA English DT Article ID INDIRECTLY DRIVEN; NOVA; GROWTH; TARGETS; SPECTRA AB A highly uniform thermal x-radiation field for indirect-drive inertial confinement fusion implosions may be obtained by irradiating a four-hole, tetrahedral geometry, spherical hohlraum with all 60 Omega laser beams. Implosion studies and calculations [J. M. Wallace , Phys. Rev. Lett. 82, 3807 (1999)] indicate a drive uniformity comparable to that expected for the National Ignition Facility [J. A. Painser , Laser Focus World 30, 75 (1994)]. With 60 beams distributed over the cavity wall, tetrahedral hohlraums have a natural insensitivity to power balance and pointing errors. Standard, smooth Nova capsules imploded with this drive indicate that moderate convergence-ratio implosions, Cr similar to 18, have measured-neutron yield to calculated-clean-one-dimensional-neutronyield ratios similar to those previously investigated using the comparatively poor drive uniformity of Nova cylindrical hohlraums. This may indicate that a nonsymmetry-related neutron yield degradation mechanism, e.g., hydrodynamic mixing of cold, dense ablator material with the hot-spot region or some combination of nonsymmetry effects, is dominating in this Cr regime. (C) 2000 American Institute of Physics. [S1070-664X(00)04305-6]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Rochester, Laser Energet Lab, Rochester, NY 14623 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Bennett, GR (reprint author), Sandia Natl Labs, Ktech Corp, Mail Stop 1106,POB 5800, Albuquerque, NM 87185 USA. RI Schnittman, Jeremy/D-3168-2012; Murphy, Thomas/F-3101-2014 OI Murphy, Thomas/0000-0002-6137-9873 NR 28 TC 15 Z9 15 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2594 EP 2603 AR PII [S1070-664X(00)04305-6] DI 10.1063/1.874101 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500044 ER PT J AU Davidson, RC Strasburg, S AF Davidson, RC Strasburg, S TI Warm-fluid stability properties of intense non-neutral charged particle beams with pressure anisotropy SO PHYSICS OF PLASMAS LA English DT Article ID VLASOV-MAXWELL EQUATIONS; PERIODIC FOCUSING FIELD; DELTA-F SIMULATION; PROPAGATION; EQUILIBRIUM; FUSION AB The macroscopic warm-fluid model developed by Lund and Davidson [Phys. Plasmas 5, 3028 (1998)] is used in the smooth-focusing approximation to investigate detailed electrostatic stability properties of an intense charged particle beam with pressure anisotropy. The macroscopic fluid-Maxwell equations are linearized for small-amplitude perturbations, and an eigenvalue equation is derived for the perturbed electrostatic potential delta phi(x,t), allowing for arbitrary anisotropy in the perpendicular and parallel pressures, P-perpendicular to(0)(r) and P-parallel to(0)(r). Detailed stability properties are calculated numerically for the case of extreme anisotropy with P-parallel to(0)(r)=0 and P-perpendicular to(0)(r)not equal 0, assuming axisymmetric wave perturbations (partial derivative/partial derivative theta=0) of the form delta phi(x,t)=delta<(phi)over cap>(r)exp(ik(z)z-i omega t), where k(z) is the axial wavenumber, and Im omega > 0 corresponds to instability (temporal growth). For k(z)=0, the analysis of the eigenvalue equation leads to a discrete spectrum {omega(n)} of stable oscillations with Im omega(n)=0, where n is the radial mode number. On the other hand, for sufficiently large values of k(z)r(b), where r(b) is the beam radius, the analysis leads to an anisotropy-driven instability (Im omega > 0) provided the normalized Debye length (Gamma(D)=lambda(D perpendicular to)/r(b)) is sufficiently large and the normalized beam intensity (s(b)=<(omega)over cap>(2)(pb)/2 gamma(b)(2)omega(beta perpendicular to)(2)) is sufficiently below the space-charge limit. Depending on system parameters, the growth rate can be a substantial fraction of the focusing frequency omega(beta perpendicular to) of the applied field. (C) 2000 American Institute of Physics. [S1070-664X(00)02506-4]. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Davidson, RC (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 49 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2657 EP 2670 DI 10.1063/1.874108 PG 14 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500051 ER PT J AU Karasik, M Roquemore, AL Zweben, SJ AF Karasik, M Roquemore, AL Zweben, SJ TI Experiment and modeling of an atmospheric pressure arc in an applied oscillating magnetic field SO PHYSICS OF PLASMAS LA English DT Article AB A set of experiments are carried out to measure and understand the response of a free-burning atmospheric pressure carbon arc to applied transverse dc and ac magnetic fields. The arc is found to deflect parabolically for the dc field and assumes a growing sinusoidal structure for the ac field. A simple analytic two-parameter fluid model of the arc dynamics is derived, in which the arc response is governed by the arc jet originating at the cathode, with the applied JxB force balanced by inertia. Time variation of the applied field allows evaluation of the parameters individually. A fit of the model to the experimental data gives a value for the average jet speed an order of magnitude below Maecker's estimate of the maximum jet speed [H. Maecker, Z. Phys. 141, 198 (1955)]. An example industrial application of the model is considered. (C) 2000 American Institute of Physics. [S1070-664X(00)04406-2]. C1 Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. RP Karasik, M (reprint author), USN, Res Lab, Code 6731,4555 Overlook Ave SW, Washington, DC 20375 USA. NR 35 TC 3 Z9 3 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUN PY 2000 VL 7 IS 6 BP 2715 EP 2727 AR PII [S1070-664X(00)04406-2] DI 10.1063/1.874115 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 321KW UT WOS:000087455500058 ER PT J AU Pogorelsky, I AF Pogorelsky, I TI Andrei Tsolakovitch Amatuni - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 Brookhaven Natl Lab, Upton, NY 11973 USA. RP Pogorelsky, I (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD JUN PY 2000 VL 53 IS 6 BP 69 EP 69 DI 10.1063/1.1306379 PG 1 WC Physics, Multidisciplinary SC Physics GA 319KE UT WOS:000087339400018 ER PT J AU Crease, RP AF Crease, RP TI Dedications: that's what you need SO PHYSICS WORLD LA English DT Editorial Material C1 SUNY Stony Brook, Dept Philosophy, Stony Brook, NY 11794 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Crease, RP (reprint author), SUNY Stony Brook, Dept Philosophy, Stony Brook, NY 11794 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8585 J9 PHYS WORLD JI Phys. World PD JUN PY 2000 VL 13 IS 6 BP 19 EP 20 PG 2 WC Physics, Multidisciplinary SC Physics GA 321XB UT WOS:000087479000016 ER PT J AU McEuen, PL AF McEuen, PL TI Single-wall carbon nanotubes SO PHYSICS WORLD LA English DT Article C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RP McEuen, PL (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. RI 李, 府中/H-4357-2011 NR 6 TC 136 Z9 138 U1 2 U2 11 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8585 J9 PHYS WORLD JI Phys. World PD JUN PY 2000 VL 13 IS 6 BP 31 EP 36 PG 6 WC Physics, Multidisciplinary SC Physics GA 321XB UT WOS:000087479000027 ER PT J AU Nellis, WJ AF Nellis, WJ TI Metallization of fluid hydrogen at 140 GPa (1.4 Mbar): implications for Jupiter SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Symposium on the Jovian System after Galileo/The Saturnian System before Cassini-Huygens CY MAY 11-15, 1998 CL NANTES, FRANCE SP European Union, European Space Agcy, CNES, French Minist Educ Natl, CNRS, City Nantes, Univ Nantes, Reg Pays Loire, COSPAR ID COMPRESSED LIQUID-HYDROGEN; EQUATION-OF-STATE; MOLECULAR-HYDROGEN; ELECTRICAL-CONDUCTIVITY; MEGABAR PRESSURES; MAGNETIC-FIELD; GIANT PLANETS; TEMPERATURE-MEASUREMENTS; SHOCK PRESSURES; DENSE HYDROGEN AB Implications of recent electrical conductivity and equation-of-state measurements on hydrogen at shock pressures up to 180 GPa and temperatures up to 4000 K are discussed. The laboratory results suggest that the transition between molecular and monatomic hydrogen is continuous, rather than first-order. Thus, it is unlikely that there is a distinct boundary in Jupiter between a molecular mantle and monatomic core. Rather, molecular hydrogen begins to dissociate at similar to 40 GPa and goes to completion at similar to 300 GPa. The electrical conductivity of fluid hydrogen reaches the minimum conductivity of a disordered metal at 140 GPa and similar to 3000 K in the middle of this complex region. This pressure corresponds to about 0.9 the outer radius of Jupiter. The surface magnetic field of Jupiter, similar to 10 G, is relatively large because metallic conductivity is reached relatively close to the planet's surface. In comparison, the magnetic field of Saturn is only 0.2 G and is made primarily at 0.5 of the outer radius of Saturn, very similar to Earth. The shallow slope of temperature versus pressure along the isentrope of hydrogen suggests that the He content might have a significant effect on convection and, thus, on the Jovian magnetic field. Higher-order components of Jupiter's magnetic field might be affected by inhibition of convection due to properties of the continuous dissociative phase transition of hydrogen. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Nellis, WJ (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 53 TC 51 Z9 51 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD JUN-JUL PY 2000 VL 48 IS 7-8 BP 671 EP 677 DI 10.1016/S0032-0633(00)00031-3 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 338PK UT WOS:000088428300004 ER PT J AU Isopp, H Frehner, M Long, SP Nosberger, J AF Isopp, H Frehner, M Long, SP Nosberger, J TI Sucrose-phosphate synthase responds differently to source-sink relations and to photosynthetic rates: Lolium perenne L. growing at elevated p(CO2) in the field SO PLANT CELL AND ENVIRONMENT LA English DT Article DE Lolium perenne; amino acid; carbon dioxide enrichment; fructan; nitrogen fertilization; photosynthesis; protein; source-sink ratio; sucrose; sucrose-phosphate synthase ID ATMOSPHERIC CARBON-DIOXIDE; AIR CO2 ENRICHMENT; HIGHER-PLANTS; NITROGEN NUTRITION; SPINACH LEAVES; METABOLISM; EXPRESSION; ACCLIMATION; TEMPERATURE; RYEGRASS AB Lolium perenne, a main component species in managed grassland, is well adapted to defoliation, fertilization, and regrowth cycles; and hence, to changes in the assimilatory carbon source-sink ratio. In the Swiss Free Air CO(2) Enrichment experiment the source-sink ratio is (i) increased by elevated partial pressure of CO(2) (p(CO2)), (ii) decreased by enhanced carbon use under high N fertilization, and (iii) gradually increased during regrowth after defoliation. Since sucrose synthesis plays a central role in leaf carbohydrate metabolism in this fructan-accumulating species, we investigated how sucrose-phosphate synthase (SPS) responds to the differing assimilatory carbon fluxes and source-sink ratios in the field, Assimilatory carbon flux, as estimated by leaf gas exchange, strongly depended on p(CO2). Surprisingly, the SPS content per leaf area did not increase with p(CO2), but increased with N fertilization. During later regrowth, when a dense canopy had formed, the SPS content decreased; in particular, SPS was decreased at high N under elevated p(CO2). Further, the higher assimilatory carbon flux through SPS at elevated p(CO2) was accompanied by a higher activation state of SPS, The SPS content correlated very strongly with the ratio of free sucrose to free amino acid in leaves, which represents the carbon source-sink ratio. Hence, SPS content in L. perenne appears to be regulated by the current, strongly nitrogen-dependent, source-sink relation. C1 Swiss Fed Inst Technol, Inst Plant Sci, CH-8092 Zurich, Switzerland. Univ Essex, Dept Biol Sci, John Tabor Labs, Colchester CO4 3SQ, Essex, England. Brookhaven Natl Lab, Environm Biol & Instrumentat Div, Upton, NY 11973 USA. RP Frehner, M (reprint author), Swiss Fed Inst Technol, Inst Plant Sci, Univ Str 2, CH-8092 Zurich, Switzerland. EM marco.frehner@ipw.agrl.ethz.ch RI Long, Stephen/A-2488-2008 OI Long, Stephen/0000-0002-8501-7164 NR 43 TC 35 Z9 40 U1 1 U2 11 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0140-7791 J9 PLANT CELL ENVIRON JI Plant Cell Environ. PD JUN PY 2000 VL 23 IS 6 BP 597 EP 607 DI 10.1046/j.1365-3040.2000.00583.x PG 11 WC Plant Sciences SC Plant Sciences GA 328YK UT WOS:000087879200006 ER PT J AU Park, JH Pfender, E Chang, CH AF Park, JH Pfender, E Chang, CH TI Reduction of chemical reactions in nitrogen and nitrogen-hydrogen plasma jets flowing into atmospheric air SO PLASMA CHEMISTRY AND PLASMA PROCESSING LA English DT Article DE numerical simulation; plasma jet; chemical nonequilibrium; reduction of chemical reactions; sensitivity analysis ID COMBUSTION; CHEMISTRY; METHANE AB The large number of possible chemical reactions represents a severe burden for modeling of even relatively simple plasma systems. Reduced sets of chemical reactions have been obtained for numerical simulations of nitrogen and nitrogen-hydrogen plasma jets flowing into an atmospheric air environment. The important or active reactions are determined based on a simplified reduction method. A reaction is considered active if it leads to higher sensitivities than a specified cutoff sensitivity of 1%. The active reactions exert a significant influence on main plasma parameters, such as velocity, temperature, and species concentrations. The sensitivity analysis for the specified systems shows that two NO reactions, known as Zel'dovich reactions (N-2 + O <-> NO + N and NO + O <-> O-2 + N),((I)) are both active in a nitrogen plasma jet. On the other hand, the latter is not active and may be omitted in a nitrogen-hydrogen plasma jet. A nitrogen-hydrogen plasma jet requires contribution of two active charge exchange reactions: N-2 + N+ <-> N-2(+) + N and N + H + <-> N + + H, while only the former is needed in a nitrogen plasma jet. The dissociation reactions are all active in both plasma jets, except the dissociation of OH. C1 Univ Minnesota, Dept Mech Engn, Minneapolis, MN 55455 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Park, JH (reprint author), Univ Minnesota, Dept Mech Engn, 111 Church St SE, Minneapolis, MN 55455 USA. NR 26 TC 15 Z9 15 U1 0 U2 9 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4324 J9 PLASMA CHEM PLASMA P JI Plasma Chem. Plasma Process. PD JUN PY 2000 VL 20 IS 2 BP 165 EP 181 DI 10.1023/A:1007087105887 PG 17 WC Engineering, Chemical; Physics, Applied; Physics, Fluids & Plasmas SC Engineering; Physics GA 326BF UT WOS:000087711500001 ER PT J AU Sanchez, R Hirshman, SP Ware, AS Berry, LA Spong, DA AF Sanchez, R Hirshman, SP Ware, AS Berry, LA Spong, DA TI Ballooning stability optimization of low-aspect-ratio stellarators SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID DEVICES AB The implementation of ideal ballooning stability within an optimization code is used to determine stable, moderate-beta compact stellarator configurations. Due to the large computational requirements of existing ballooning codes, such calculations within the optimization process were previously impractical. The recently developed COBRA code can efficiently compute ideal ballooning growth rates on various magnetic surfaces, using the VMEC code to supply equilibrium data. The optimization code has been used to minimize these growth rates, giving rise to new stellarator configurations at low aspect ratios with good ballooning stability properties, which also maintain previously determined desirable physics properties. This particular implementation is robust due to the enhanced convergence features included in COBRA, while incurring only a small overhead on the total computational time. C1 Univ Carlos III Madrid, Dept Fis, Madrid 28911, Spain. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Univ Montana, Dept Phys & Astron, Missoula, MT 59801 USA. RP Sanchez, R (reprint author), Univ Carlos III Madrid, Dept Fis, Avda Univ 30, Madrid 28911, Spain. EM rsanchez@fis.uc3m.es RI Sanchez, Raul/C-2328-2008; Spong, Donald/C-6887-2012 OI Spong, Donald/0000-0003-2370-1873 NR 23 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 EI 1361-6587 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD JUN PY 2000 VL 42 IS 6 BP 641 EP 653 DI 10.1088/0741-3335/42/6/303 PG 13 WC Physics, Fluids & Plasmas SC Physics GA 330KQ UT WOS:000087961600003 ER PT J AU Rusch, GM Garrett, R Tobin, P Falke, E Lu, PY AF Rusch, GM Garrett, R Tobin, P Falke, E Lu, PY TI The development of acute exposure guideline levels for hazardous substances SO PROCESS SAFETY PROGRESS LA English DT Article; Proceedings Paper CT 34th Annual Symposium on Loss Prevention CY MAR 05-09, 2000 CL ATLANTA, GEORGIA ID HISTORY AB The primary purpose of the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL) is to develop guideline levels for short-term exposures to airborne concentrations for approximately 400 to 500 high priority, acutely hazardous substances within the next ten years. These Acute Exposure Guideline Levels (AEGLs) are needed for a wide range of planning, response, and prevention applications. The NAC/AEGL Committee seeks to develop the most scientifically credible, acute (short-term) exposure guideline levels possible within the constraints of data availability, resources and time. This includes a comprehensive effort in data gathering, data evaluation and data summarization; fostering the participation of a large cross-section of the relevant scientific community; and the adoption of procedures and methods that facilitate consensus-building for AEGL values within the Committee. The NAC/AEGL Committee is currently comprised of representatives of federal, state and local agencies, private industry and other organizations in the private sector that will derive programmatic or operational benefits form the existence of the AEGL values. AEGL values are determined for three different health effect end-points. These values are intended for the general public where they are applicable to emergency (accidental) situation. Threshold exposure values are developed for a minimum of 4 exposure periods (30 minutes, 1 hour, 4 hours, 8 hours). In certain instances, AEGL values for a 10-minute exposure period also will be developed. Each threshold value is distinguished by varying degrees of severity of toxic effects, as initially conceived by the AIHA ERP Committee, subsequently defined in the NAS' National Research Council Report, Guidelines for Developing Community Emergency Exposure Levels for Hazardous Substances, published by the National Academy of Sciences in 1993, and further refined by the NAC/AEGL Committee. To date, the committee has reviewed over 80 chemicals. C1 Honeywell Inc, Morristown, NJ 07962 USA. US EPA, Washington, DC 20460 USA. Oak Ridge Natl Lab, Toxicol & Risk Anal, Oak Ridge, TN 37830 USA. RP Rusch, GM (reprint author), Honeywell Inc, 101 Columbia Rd, Morristown, NJ 07962 USA. NR 5 TC 4 Z9 4 U1 0 U2 0 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 3 PARK AVE, NEW YORK, NY 10016-5901 USA SN 1066-8527 J9 PROCESS SAF PROG JI Process Saf. Prog. PD SUM PY 2000 VL 19 IS 2 BP 98 EP 102 DI 10.1002/prs.680190209 PG 5 WC Engineering, Chemical SC Engineering GA 326DB UT WOS:000087716500016 ER PT J AU Van Hove, MA AF Van Hove, MA TI Challenges of structure determination of compound surfaces SO PROGRESS IN SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 8th Symposium on Surface Physics CY JUN 28-JUL 02, 1999 CL TREST CASTLE, CZECH REPUBLIC SP Acad Sci Czech Republic, Inst Phys, Technolog Fdn Czech Republic DE surface structure; surface structure determination; compounds; complex structures; disorder; polar ionic surfaces; coexistence of structures; low-energy electron diffraction; x-ray diffraction; photoelectron diffraction ID LEED CRYSTALLOGRAPHY; ELECTRON-DIFFRACTION; FE3O4(111); TERMINATION; PT(111) AB Attention is drawn to challenges facing the structure determination of compound surfaces of growing complexity. Besides the questions of large unit cells and disorder, and of many independent atoms in the unit cells, one must address the determination of composition, compositional disorder and simultaneously coexisting structures. OF special concern is the issue of stability of complex and compound surfaces, and the resulting concerns about experimental surface preparation and reproducibility. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. RP Van Hove, MA (reprint author), Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 26 TC 5 Z9 5 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0079-6816 J9 PROG SURF SCI JI Prog. Surf. Sci. PD JUN-AUG PY 2000 VL 64 IS 3-8 BP 157 EP 162 DI 10.1016/S0079-6816(00)00010-1 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 318PV UT WOS:000087293800006 ER PT J AU Van Hove, MA AF Van Hove, MA TI The Castle Symposia SO PROGRESS IN SURFACE SCIENCE LA English DT Editorial Material C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Davis, Davis, CA 95616 USA. RP Van Hove, MA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0079-6816 J9 PROG SURF SCI JI Prog. Surf. Sci. PD JUN-AUG PY 2000 VL 64 IS 3-8 BP 225 EP 227 DI 10.1016/S0079-6816(00)00008-3 PG 3 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 318PV UT WOS:000087293800012 ER PT J AU Kadkhodayan, S Knapp, MS Schmidt, JJ Fabes, SE Rupp, B Balhorn, R AF Kadkhodayan, S Knapp, MS Schmidt, JJ Fabes, SE Rupp, B Balhorn, R TI Cloning, expression, and one-step purification of the minimal essential domain of the light chain of botulinum neurotoxin type A SO PROTEIN EXPRESSION AND PURIFICATION LA English DT Article ID TOXIN TYPE-A; NEUROTRANSMITTER RELEASE; PROTEOLYTIC CLEAVAGE; B NEUROTOXIN; TETANUS; TOXICITY; PROTEIN; SNAP-25 AB A truncated but functional form of the botulinum neurotoxin A light chain (Tyr 9-Leu 415) has been cloned into the three bacterial expression vectors, PET 28, pET 30, and PGEX-2T, and produced as fusion proteins. This 406-amino-acid light chain was expressed with 1 six-histidine tag (LC-pET28), 2 six histidine tags and a S-tag (LC-pET30), or a six-histidine tag and a glutathione S-transferase tag (LC-pGEX-2T). The three fusion proteins have been overexpressed in Escherichia coli, purified in a soluble form, and tested for protease activity. All three recombinant proteins were found to have similar enzymatic activity, comparable to the light chain purified from the whole toxin, The LC-pET30 protein was the most soluble and stable of the three fusion proteins, and it could be purified using a one-step affinity chromatography protocol. The purified protein was determined to be 98% pure as assessed by SDS-polyacrylamide gel. This protein has been crystallized and initial X-ray data show that the crystals diffract to 1.8 Angstrom. (C) 2000 Academic Press. C1 L441 Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. USA, Med Res Inst Infect Dis, Div Toxicol, Ft Detrick, MD 21702 USA. RP Kadkhodayan, S (reprint author), L441 Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, POB 808, Livermore, CA 94551 USA. NR 18 TC 19 Z9 23 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1046-5928 J9 PROTEIN EXPRES PURIF JI Protein Expr. Purif. PD JUN PY 2000 VL 19 IS 1 BP 125 EP 130 DI 10.1006/prep.2000.1227 PG 6 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 323LF UT WOS:000087566300016 PM 10833399 ER PT J AU Huang, CM Yuan, JP Cao, H Zhang, R Jean, YC Suzuki, R Ohdaira, T Nielsen, B AF Huang, CM Yuan, JP Cao, H Zhang, R Jean, YC Suzuki, R Ohdaira, T Nielsen, B TI Positron annihilation studies of chromophore-doped polymers SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 6th International Workshop on Positron and Positronium Chemistry (PPC-6) CY JUN 07-11, 1999 CL TSUKUBA, JAPAN DE nonlinear optical; chromophore; polymers; free volume ID SPECTROSCOPY AB Doppler-broadening energy spectra and positron annihilation lifetime have been measured as a function of positron implantation energy in pure and chromophore Disperse Red I (DR1)-doped poly(methyl methacrylate) (PMMA) polymers. In pure PMMA, the S parameter increases at very short range (< 0.02 mu m) from the surface to the bulk, while the S parameter of doped PMMA varies with a decrease from a depth of > 0.02 mu m to about 0.5 mu m after an increase, a short distance from the surface. The o-Ps lifetime of the polymers is found to increase from the bulk to the surface, which indicates that the hole size expands near the surface. The o-Ps lifetime distribution becomes broader near the surface. The change of the o-Ps intensity shows the same trend as the change of the S parameter. These results are interpreted as a gradient of DR1 concentration in PMMA, as a function of the depth from the surface to the bulk in the chromophore-doped polymers. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Jean, YC (reprint author), Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. RI Nielsen, Bent/B-7353-2009 OI Nielsen, Bent/0000-0001-7016-0040 NR 7 TC 5 Z9 5 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 2000 VL 58 IS 5-6 BP 571 EP 574 DI 10.1016/S0969-806X(00)00220-6 PG 4 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 333YX UT WOS:000088159300029 ER PT J AU Zhang, R Cao, H Chen, HM Mallon, P Sandreczki, T Richardson, JR Jean, YC Nielsen, B Suzuki, R Ohdaira, T AF Zhang, R Cao, H Chen, HM Mallon, P Sandreczki, T Richardson, JR Jean, YC Nielsen, B Suzuki, R Ohdaira, T TI Development of positron annihilation spectroscopy to test accelerated weathering of protective polymer coatings SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 6th International Workshop on Positron and Positronium Chemistry (PPC-6) CY JUN 07-11, 1999 CL TSUKUBA, JAPAN DE positron beam; weathering; coatings; polymers; degradation ID DEGRADATION AB A variable mono-energetic positron beam with a computer-controlled system has recently been constructed at the University of Missouri-Kansas City for weathering studies of polymeric coatings. The beam is designed to measure the S-parameter from Doppler-broadening energy spectra and the sub-nanometer defect properties from positron annihilation lifetimes (PAL). Significant variations of S-parameter and ortho-positronium intensity in coatings, as obtained from the newly built beam and from the Electrotechnical Laboratory's beam, respectively, are observed as a function of depth and exposure time due to the Xe-light irradiation. A high sensitivity of positron annihilation signal response to the early stage of degradation is observed. Development of positron annihilation spectroscopy to test accelerated weathering of polymeric coatings is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. RP Jean, YC (reprint author), Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. RI Nielsen, Bent/B-7353-2009 OI Nielsen, Bent/0000-0001-7016-0040 NR 8 TC 41 Z9 44 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 2000 VL 58 IS 5-6 BP 639 EP 644 DI 10.1016/S0969-806X(00)00235-8 PG 6 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 333YX UT WOS:000088159300041 ER PT J AU Cao, H Zhang, R Chen, HM Mallon, P Huang, CM He, Y Sandreczki, TC Jean, YC Nielsen, B Friessnegg, T Suzuki, R Ohdaira, T AF Cao, H Zhang, R Chen, HM Mallon, P Huang, CM He, Y Sandreczki, TC Jean, YC Nielsen, B Friessnegg, T Suzuki, R Ohdaira, T TI Application of slow positrons to coating degradation SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 6th International Workshop on Positron and Positronium Chemistry (PPC-6) CY JUN 07-11, 1999 CL TSUKUBA, JAPAN DE slow positrons; coatings; photo-degradation; polymers ID ANNIHILATION SPECTROSCOPY AB Photodegradation of a polyurethane-based topcoat induced by accelerated UV irradiation is studied using Doppler broadened energy spectra (DBES) and positron annihilation lifetime (PAL) spectroscopies coupled with slow positron technique. Significant and similar variations of S-parameter and ortho-positronium intensity (I(3)) in coatings an observed as functions of depth and of exposure time. The decrease of S is interpreted as a result of an increase of crosslink density and a reduction of free-volume and hole fraction during the degradation process. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. RP Jean, YC (reprint author), Univ Missouri, Dept Chem, Kansas City, MO 64110 USA. EM jeany@umkc.edu RI Nielsen, Bent/B-7353-2009 OI Nielsen, Bent/0000-0001-7016-0040 NR 5 TC 8 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 2000 VL 58 IS 5-6 BP 645 EP 648 DI 10.1016/S0969-806X(00)00237-1 PG 4 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 333YX UT WOS:000088159300042 ER PT J AU Schrader, DM Moxom, J AF Schrader, DM Moxom, J TI Present and future positron-molecular scattering experiments SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 6th International Workshop on Positron and Positronium Chemistry (PPC-6) CY JUN 07-11, 1999 CL TSUKUBA, JAPAN ID QUANTUM MONTE-CARLO; CROSSED-BEAM MEASUREMENT; BINDING-ENERGIES; DOUBLE-IONIZATION; NOBLE-GASES; RECOIL IONS; ANNIHILATION; HYDRIDE; IMPACT; FRAGMENTATION AB Progress to date (June, 1999) of the Oak Ridge positron scattering project is reviewed. Results from our positron time-of-flight mass spectrometer include ionization and fragmentation of some halomethanes, positronium formation below the threshold for double ionization of Ne and the heavier noble gases, and the production of HeH+ by positron impact on mixtures of He and H-2. New directions for future experimental work are discussed. These entail the construction and testing of a new spectrometer which measures both the masses and recoil energies of charged products, including secondary electrons. We hope to use an intense positron beam, such as the one at Lawrence Livermore National Laboratory or a similar beam, as the ionizing agent for the new spectrometer, which contains a pulsed supersonic molecular beam. With such an instrument, a range of new phenomena can be studied. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Marquette Univ, Dept Chem, Milwaukee, WI 53201 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Schrader, DM (reprint author), Marquette Univ, Dept Chem, POB 1881, Milwaukee, WI 53201 USA. NR 36 TC 1 Z9 1 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUN PY 2000 VL 58 IS 5-6 BP 649 EP 654 DI 10.1016/S0969-806X(00)00231-0 PG 6 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 333YX UT WOS:000088159300043 ER PT J AU Kraemer, SM Kronenberg, A Ueno, A Waldren, CA AF Kraemer, SM Kronenberg, A Ueno, A Waldren, CA TI Measuring the spectrum of mutation induced by nitrogen ions and protons in the human-hamster hybrid cell line A(L)C SO RADIATION RESEARCH LA English DT Article ID MAMMALIAN-CELLS; MUTANT QUANTITY; RADIATION; MUTAGENESIS; CHROMOSOME; DNA; LYMPHOCYTES; ASTRONAUTS; PARTICLES; EXPOSURE AB Astronauts can be exposed to charged particles, including protons, alpha particles and heavier ions, during space flights. Therefore, studying the biological effectiveness of these sparsely and densely ionizing radiations is important to understanding the potential health effects for astronauts. We evaluated the mutagenic effectiveness of sparsely ionizing 55 MeV protons and densely ionizing 32 MeV/nucleon nitrogen ions using cells of two human-hamster cell lines, A(L) and A(L)C, We have previously characterized a spectrum of mutations, including megabase deletions, in human chromosome 11, the sole human chromosome in the human-hamster hybrid cell lines A(L)C and A(L). CD59- mutants have lost expression of a human cell surface antigen encoded by the CD59 gene located at 11p13, Deletion of genes located on the tip of the short arm of 11 (11p15.5) is lethal to the A(L) hybrid, so that CD59 mutants that lose the entire chromosome 11 die and escape detection. In contrast, deletion of the 11p15.5 region is not lethal in the hybrid A(L)C, allowing for the detection of chromosome loss or other chromosomal mutations involving 11p15.5, The 55 MeV protons and 32 MeV/nucleon nitrogen ions were each about 10 times more mutagenic per unit dose at the CD59 locus in A(L)C cells than in A(L) cells. In the case of nitrogen ions, the mutations observed in A(L)C cells were predominantly due to chromosome loss events or 11p deletions, often containing a breakpoint in the pericentromeric region. The increase in the CD59- mutant fraction for A(L)C cells exposed to protons was associated with either translocation of portions of 11q onto a hamster chromosome, or discontinuous or "skipping" mutations. We demonstrate here that A(L)C cells are a powerful tool that will aid In the understanding of the mutagenic effects of different types of ionizing radiation. (C) 2000 by Radiation Research. Society. C1 Colorado State Univ, Dept Radiol Hlth Sci, Ft Collins, CO 80523 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Colorado State Univ, Dept Biochem & Mol Biol, Ft Collins, CO 80523 USA. RP Waldren, CA (reprint author), Colorado State Univ, Dept Radiol Hlth Sci, Ft Collins, CO 80523 USA. FU NCI NIH HHS [CA36447, CA09236] NR 36 TC 11 Z9 11 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 2000 VL 153 IS 6 BP 743 EP 751 DI 10.1667/0033-7587(2000)153[0743:MTSOMI]2.0.CO;2 PG 9 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 319JD UT WOS:000087337000003 PM 10825749 ER PT J AU Ulsh, BA Muhlmann-Diaz, MC Whicker, FW Hinton, TG Congdon, JD Bedford, JS AF Ulsh, BA Muhlmann-Diaz, MC Whicker, FW Hinton, TG Congdon, JD Bedford, JS TI Chromosome translocations in turtles: A biomarker in a sentinel animal for ecological dosimetry SO RADIATION RESEARCH LA English DT Article ID IN-SITU HYBRIDIZATION; RADIATION-INDUCED TRANSLOCATIONS; IONIZING-RADIATION; HUMAN-LYMPHOCYTES; GAMMA-RADIATION; DNA LIBRARIES; STRUCTURAL-ABERRATIONS; BIOLOGICAL DOSIMETRY; PERSISTENCE; DICENTRICS AB Nonhuman organisms are being exposed to ionizing radiations at radionuclide-contaminated sites around the world. Direct methods are seldom available for measuring biologically relevant doses received by these organisms. Here we extend biological dosimetry techniques, which are much better developed for humans and a few other mammalian species, to a nonmammalian species. Turtles were chosen because a long-lived animal would best serve the need for low-level, chronic exposure conditions, We chose the yellow-bellied slider turtle (Trachemys scripta), which is known to have a maximum life span of at least 22 years. As reported elsewhere, we first isolated an embryonic fibroblast cell line and constructed whole-chromosome-specific DNA libraries for chromosome 1 by microdissection and PCR. A FISH painting probe was prepared and used to establish a dose-response curve for ionizing radiation-induced chromosome interchange aberrations in turtle fibroblasts. This was compared to the dose response for human fibroblasts treated under similar conditions in our laboratory. With respect to induction of chromosome interchange aberrations, human fibroblasts were approximately 1.7 times more sensitive than the T. scripta fibroblasts. To the extent that symmetrical interchanges are persistent over long periods, this approach could eventually provide a measure of the integrated lifetime dose these organisms receive from radionuclides in their environment and give a measure of the extent of relevant genetic damage over that time, (C) 2000 by Radiation Research Society. C1 Colorado State Univ, Dept Radiol Hlth Sci, Ft Collins, CO 80523 USA. Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Bedford, JS (reprint author), Colorado State Univ, Dept Radiol Hlth Sci, Ft Collins, CO 80523 USA. FU NCI NIH HHS [5 T32 CA09236] NR 56 TC 12 Z9 13 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 2000 VL 153 IS 6 BP 752 EP 759 DI 10.1667/0033-7587(2000)153[0752:CTITAB]2.0.CO;2 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 319JD UT WOS:000087337000004 PM 10825750 ER PT J AU Fouladi, B Waldren, CA Rydberg, B Cooper, PK AF Fouladi, B Waldren, CA Rydberg, B Cooper, PK TI Comparison of repair of DNA double-strand breaks in identical sequences in primary human fibroblast and immortal hamster-human hybrid cells harboring a single copy of human chromosome 11 SO RADIATION RESEARCH LA English DT Article ID FIELD GEL-ELECTROPHORESIS; PROTEIN-KINASE ACTIVITY; IONIZING-RADIATION; HOMOLOGOUS RECOMBINATION; V(D)J RECOMBINATION; MAMMALIAN-CELLS; MOUSE HOMOLOGS; X-IRRADIATION; OVARY CELLS; HUMAN MRE11 AB We have optimized a pulsed-field gel electrophoresis assay that measures induction and repair of double-strand breaks (DSBs) in specific regions of the genome (Lobrich et al,, Proc. Natl, Acad, Sci, USA 92, 12050-12054, 1995), The increased sensitivity resulting from these improvements makes it possible to analyze the size distribution of broken DNA molecules immediately after the introduction of DSBs and after repair incubation. This analysis shows that the distribution of broken DNA pieces after exposure to sparsely ionizing radiation is consistent with the distribution expected from randomly induced DSBs, It is apparent from the distribution of rejoined DNA pieces after repair incubation that DNA ends continue to rejoin between 3 and 24 h postirradiation and that some of these rejoining events are in fact misrejoining events, since novel restriction fragments both larger and smaller than the original fragment are generated after repair. This improved assay was also used to study the kinetics of DSB rejoining and the extent of misrejoining in identical DNA sequences in human GM38 cells and human-hamster hybrid A(L) cells containing a single human chromosome Il, Despite the numerous differences between these cells, which include species and tissue of origin, levels of TP53, expression of telomerase, and the presence or absence of a homologous chromosome for the restriction fragments examined, the kinetics of rejoining of radiation-induced DSBs and the extent of misrejoining were similar in the two cell lines when studied in the G(I) phase of the cell cycle, Furthermore, DSBs were removed from the single-copy human chromosome in the hamster A(L) cells with similar kinetics and misrejoining frequency as at a locus on this hybrid's CHO chromosomes. (C) 2000 by Radiation Research Society. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Cell & Mol Biol, Div Life Sci, Berkeley, CA 94720 USA. Colorado State Univ, Dept Radiol Hlth Sci, Ft Collins, CO 80523 USA. RP Cooper, PK (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Dept Cell & Mol Biol, Div Life Sci, Bldg 74,Room 303,1 Cyclotron Rd, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA36447, CA09236] NR 61 TC 28 Z9 29 U1 1 U2 1 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 2000 VL 153 IS 6 BP 795 EP 804 DI 10.1667/0033-7587(2000)153[0795:CORODD]2.0.CO;2 PG 10 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 319JD UT WOS:000087337000009 PM 10825755 ER PT J AU Rydberg, B AF Rydberg, B TI Radiation-induced heat-labile sites that convert into DNA double-strand breaks SO RADIATION RESEARCH LA English DT Article ID FIELD GEL-ELECTROPHORESIS; CHEF ELECTROPHORESIS; IONIZING-RADIATION; AQUEOUS-SOLUTION; HUMAN FIBROBLASTS; MAMMALIAN-CELLS; APURINIC SITES; SINGLE-STRAND; BASE RELEASE; DAMAGE AB The yield of DNA double-strand breaks (DSBs) in SV40 DNA irradiated in aqueous solution was found to increase by more than a factor of two as a result of postirradiation incubation of the DNA at 50 degrees C and pH 8.0 for 24 h, This is in agreement with data from studies performed at 37 degrees C that were published previously. Importantly, similar results were also obtained from irradiation of mammalian DNA in agarose plugs. These results suggest that heat-labile sites within locally multiply damaged sites are produced by radiation and are subsequently transformed into DSBs, Since incubation at 50 degrees C is typically employed for lysis of cells in commonly used pulsed-field gel assays for detection of DSBs in mammalian cells, the possibility that heat-labile sites are present in irradiated cells was also studied. An increase in the apparent number of DSBs as a function of lysis time at 50 degrees C was found with kinetics that was similar to that for irradiated DNA, although the magnitude of the increase was smaller. This suggests that heat-labile sites are also formed in the cell. If this is the case, a proportion of DSBs measured by the pulsed-field gel assays may occur during the lysis step and may not be present in the cell as breaks but as heat-labile sites. It is suggested that such sites consist mainly of heat-labile sugar lesions within locally multiply damaged sites. Comparing rejoining of DSBs measured with short and long lysis procedure indicates that the heat-labile sites are repaired with fast kinetics in comparison with repair of the bulk of DSBs, (C) 2000 by Radiation Research Society. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Rydberg, B (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, 1 Cyclotron Rd,Bldg 74, Berkeley, CA 94720 USA. FU NCI NIH HHS [CA80207] NR 38 TC 81 Z9 82 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 2000 VL 153 IS 6 BP 805 EP 812 DI 10.1667/0033-7587(2000)153[0805:RIHLST]2.0.CO;2 PG 8 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 319JD UT WOS:000087337000010 PM 10825756 ER PT J AU Stevens, RG Morris, JE Anderson, LE AF Stevens, RG Morris, JE Anderson, LE TI Hemochromatosis heterozygotes may constitute a radiation-sensitive subpopulation SO RADIATION RESEARCH LA English DT Article ID BODY IRON STORES; FREE-RADICAL DAMAGE; BREAST-CANCER; HEREDITARY HEMOCHROMATOSIS; GENETIC HEMOCHROMATOSIS; MAMMARY CARCINOGENESIS; IONIZING-RADIATION; OXIDATIVE STRESS; DIETARY IRON; DNA-DAMAGE AB A primary mechanism of radiation-induced DNA damage is by generation of free radicals. Chronically increased oxidative stress from elevated levels of iron in the body may increase radiation sensitivity by decreasing cellular oxygen radical scavenging capability. Hemochromatosis heterozygotes have elevated body iron. Low-level radiation sensitization by iron may be particularly pertinent for risk of breast cancer, Since 10% of the population appears to be heterozygous for the hemochromatosis gene, a radiosensitizing effect would have pervasive implications. (C) 2000 by Radiation Research Society. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Stevens, RG (reprint author), Univ Connecticut, Ctr Hlth, Dept Community Med, 263 Farmington Ave, Farmington, CT 06030 USA. NR 44 TC 20 Z9 20 U1 0 U2 0 PU RADIATION RESEARCH SOC PI OAK BROOK PA 2021 SPRING RD, STE 600, OAK BROOK, IL 60521 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD JUN PY 2000 VL 153 IS 6 BP 844 EP 847 DI 10.1667/0033-7587(2000)153[0844:HHMCAR]2.0.CO;2 PG 4 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 319JD UT WOS:000087337000015 PM 10825761 ER PT J AU Zettl, A AF Zettl, A TI Silencing the nanotubes SO RECHERCHE LA French DT Article ID CARBON NANOTUBES C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Zettl, A (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Zettl, Alex/O-4925-2016 OI Zettl, Alex/0000-0001-6330-136X NR 20 TC 0 Z9 0 U1 0 U2 0 PU SOC ED SCIENTIFIQUES PI PARIS 06 PA 57 RUE DE SEINE, 75280 PARIS 06, FRANCE SN 0029-5671 J9 RECHERCHE JI Recherche PD JUN PY 2000 IS 332 BP 52 EP 55 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 324GR UT WOS:000087613900013 ER PT J AU Wiser, RH AF Wiser, RH TI The role of public policy in emerging green power markets: an analysis of marketer preferences SO RENEWABLE & SUSTAINABLE ENERGY REVIEWS LA English DT Review ID ELECTRICITY; INFORMATION; TRANSITION; ISSUES AB Green power marketing has been heralded by some as a means to create a private market for renewable energy that is driven by customer demand for green products. This article challenges the premise - sometimes proffered in debates over green markets - that profitable, sizable, credible markets for green products will evolve naturally without supportive public policies. Relying primarily on surveys and interviews of US green power marketers, the article examines the role of specific regulatory and legislative policies in 'enabling' the green market, and searches for those policies that are believed by marketers to be the most conducive or detrimental to the expansion of the green market. We find that marketers: (1) believe that profitable green power markets will only develop if a solid foundation of supportive policies exists; (2) believe that establishing overall price competition and encouraging customer switching are the top priorities; (3) are somewhat leery of government-sponsored or mandated public information programs: and (4) oppose three specific renewable energy policies that are frequently advocated by renewable energy enthusiasts, but that may have negative impacts on the green marketers' profitability. The stated preferences of green marketers shed light on ways to foster renewables by means of the green market. Because the interests of marketers do not coincide perfectly with those of society, however, this study also recognizes other normative perspectives and highlights policy tensions at the heart of current debates related to green markets. By examining these conflicts, we identify three key policy questions that should direct future research: To what extent should price competition and customer switching be encouraged at the expense of cost shifting? What requirements should be imposed to ensure credibility in green products and marketing? How should the green power market and broader renewable energy policies interact? (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Wiser, RH (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, 1 Cyclotron Rd,Mailstop 90-4000, Berkeley, CA 94720 USA. NR 79 TC 8 Z9 8 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-0321 J9 RENEW SUST ENERG REV JI Renew. Sust. Energ. Rev. PD JUN PY 2000 VL 4 IS 2 BP 177 EP 212 DI 10.1016/S1364-0321(99)00015-5 PG 36 WC GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY; Energy & Fuels SC Science & Technology - Other Topics; Energy & Fuels GA 298TY UT WOS:000086156300004 ER PT J AU Zou, P Gai, W Konecny, R Sun, X Wong, T Kanareykin, A AF Zou, P Gai, W Konecny, R Sun, X Wong, T Kanareykin, A TI Construction and testing of an 11.4 GHz dielectric structure based traveling wave accelerator SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID WAKE-FIELD AB We report on the design, numerical modeling, and experimental testing of a cylindrical dielectric loaded traveling wave structure for charged particle beam acceleration. This type of structure has similar accelerating properties to disk-loaded metal slow wave structures but with some distinct advantages in terms of simplicity of fabrication and suppression of parasitic wakefield effects. Efficient coupling of external rf power to the cylindrical dielectric waveguide is a technical challenge, particularly with structures of very high dielectric constant epsilon. We have designed and constructed an X-band structure loaded with a permittivity epsilon = 20 dielectric to be powered by an external rf power source. We have attained high efficiency broadband rf coupling by using a combination of a tapered dielectric end section and a carefully adjusted coupling slot. Bench testing using a network analyzer has demonstrated a power coupling efficiency in excess of 95% with bandwidth of 30 MHz, thus providing a necessary basis for construction of an accelerator using this device. We have also simulated the parameters of this structure using a finite difference time domain electromagnetic solver. Within the limits of the approximations used, the results are in reasonable agreement with the bench measurements. (C) 2000 American Institute of Physics. [S0034-6748(00)01406-4]. C1 Argonne Natl Lab, Argonne, IL 60439 USA. IIT, Chicago, IL 60616 USA. St Petersburg Elect Engn Univ, St Petersburg 197376, Russia. RP Zou, P (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 9 TC 44 Z9 44 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2000 VL 71 IS 6 BP 2301 EP 2304 DI 10.1063/1.1150446 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 319NV UT WOS:000087348800009 ER PT J AU Saleh, N Flippo, K Nemoto, K Umstadter, D Crowell, RA Jonah, CD Trifunac, AD AF Saleh, N Flippo, K Nemoto, K Umstadter, D Crowell, RA Jonah, CD Trifunac, AD TI Pulse radiolysis of liquid water using picosecond electron pulses produced by a table-top terawatt laser system SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID WAKEFIELD AB A laser based electron generator is shown, for the first time, to produce sufficient charge to conduct time resolved investigations of radiation induced chemical events. Electron pulses generated by focussing terawatt laser pulses into a supersonic helium gas jet are used to ionize liquid water. The decay of the hydrated electrons produced by the ionizing electron pulses is monitored with 0.3 mu s time resolution. Hydrated electron concentrations as high as 22 mu M were generated. The results show that terawatt lasers offer both an alternative to linear accelerators and a means to achieve subpicosecond time resolution for pulse radiolysis studies. (C) 2000 American Institute of Physics. [S0034-6748(00)01306-X]. C1 Univ Michigan, Ctr Ultrafast Opt Sci, Ann Arbor, MI 48109 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Saleh, N (reprint author), Univ Michigan, Ctr Ultrafast Opt Sci, 2200 Bonisteel Blvd, Ann Arbor, MI 48109 USA. RI Umstadter, Donald/A-1581-2016; Flippo, Kirk/C-6872-2009 OI Umstadter, Donald/0000-0002-2182-4346; Flippo, Kirk/0000-0002-4752-5141 NR 15 TC 22 Z9 22 U1 2 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2000 VL 71 IS 6 BP 2305 EP 2308 DI 10.1063/1.1150659 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 319NV UT WOS:000087348800010 ER PT J AU Pollmann, J Srajer, G Maser, J Lang, JC Nelson, CS Venkataraman, CT Isaacs, ED AF Pollmann, J Srajer, G Maser, J Lang, JC Nelson, CS Venkataraman, CT Isaacs, ED TI Characterization of a microfocused circularly polarized x-ray probe SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID PLATES AB We report on the development of a circularly polarized x-ray microprobe in the intermediate energy range from 5 to 10 keV. In this experiment linearly polarized synchrotron radiation was circularly polarized by means of a Bragg-diffracting diamond phase retarder and subsequently focused down to a spot size of about 4 x 2 mu m(2) by a Fresnel zone plate. The properties of the microprobe were characterized, and the technique was applied to the two-dimensional mapping of magnetic domains in HoFe2. (C) 2000 American Institute of Physics. [S0034-6748(00)01206-5]. C1 Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Pollmann, J (reprint author), Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RI Maser, Jorg/K-6817-2013 NR 12 TC 10 Z9 10 U1 1 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2000 VL 71 IS 6 BP 2386 EP 2390 DI 10.1063/1.1150625 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 319NV UT WOS:000087348800021 ER PT J AU Duewer, F Gao, C Xiang, XD AF Duewer, F Gao, C Xiang, XD TI Tip-sample distance feedback control in a scanning evanescent microwave probe for nonlinear dielectric imaging SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID NEAR-FIELD MICROSCOPE; FERROELECTRIC DOMAINS; FORCE MICROSCOPY AB We implemented tip-sample distance control in a scanning evanescent microwave probe for nonlinear dielectric microscopy. With the analytic expression of the tip-sample capacitance as a function of tip-sample distance, we can quantitatively regulate the tip-sample separation and independently measure the dielectric nonlinearity by application of an ac bias voltage. Simultaneous imaging of topography and ferroelectric domains has been demonstrated on periodically poled LiNbO3 single crystals. (C) 2000 American Institute of Physics. [S0034-6748(00)05406-X]. C1 Lawrence Berkeley Lab, Environm Energies Technol Div, Berkeley, CA 94720 USA. RP Xiang, XD (reprint author), Lawrence Berkeley Lab, Environm Energies Technol Div, Berkeley, CA 94720 USA. RI Xiang, Xiaodong/A-9445-2012 NR 12 TC 9 Z9 9 U1 3 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2000 VL 71 IS 6 BP 2414 EP 2417 AR PII [S0034-6748(00)05406-X] DI 10.1063/1.1150629 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 319NV UT WOS:000087348800025 ER PT J AU Ng, KC Ford, JV Jacobson, SC Ramsey, JM Barnes, MD AF Ng, KC Ford, JV Jacobson, SC Ramsey, JM Barnes, MD TI Polymer microparticle arrays from electrodynamically focused microdroplet streams SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SINGLE-MOLECULE; BLEND MICROPARTICLES; LASER GUIDANCE; FLUORESCENCE; PARTICLES; MANIPULATION; SIZE AB We describe instrumentation for forming two-dimensional arrays of polymer microparticles produced from electrodynamically focused microdroplet streams. A single-stage linear quadrupole was used to focus droplets/particles onto silanated glass slides mounted on a computer-driven two-dimensional translation stage. Center-to-center position stability was on the order of 1 mu m. Applications to molecular sorting with polymer particles as host carriers are discussed. (C) 2000 American Institute of Physics. [S0034-6748(00)01506-9]. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Calif State Univ Fresno, Dept Chem, Fresno, CA 93740 USA. RP Barnes, MD (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. NR 18 TC 6 Z9 6 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2000 VL 71 IS 6 BP 2497 EP 2499 DI 10.1063/1.1150642 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 319NV UT WOS:000087348800040 ER PT J AU Mills, GS Neuhauser, KS AF Mills, GS Neuhauser, KS TI Quantitative methods for environmental justice assessment of transportation SO RISK ANALYSIS LA English DT Article DE environmental justice; hazardous material; transportation; relative risks; chi square AB Application of Executive Order 12898 to risk assessment of highway or rail transport of hazardous materials has proven difficult; in general, the location and conditions affecting the propagation of a plume of hazardous material released in a potential accident are unknown. Therefore, analyses have only been possible in a geographically broad or approximate manner. The advent of geographic information systems and development of software enhancements at Sandia National Laboratories have made kilometer-by-kilometer analysis of populations tallied by U.S. Census blocks along entire routes practicable. Tabulations of total or racially/ethnically distinct populations close to a route, its alternatives, or the broader surrounding area, can then be compared and differences evaluated statistically. This article presents methods of comparing populations and their racial/ethnic compositions using simple tabulations, histograms, and chi-square tests for statistical significance of differences found. Two examples of these methods are presented: comparison of two routes and comparison of a route with its surroundings. C1 Sandia Natl Labs, Dept 6331, Albuquerque, NM 87185 USA. RP Mills, GS (reprint author), Sandia Natl Labs, Dept 6331, MS 0718, Albuquerque, NM 87185 USA. NR 2 TC 9 Z9 9 U1 2 U2 4 PU BLACKWELL PUBL LTD PI OXFORD PA 108 COWLEY RD, OXFORD OX4 1JF, OXON, ENGLAND SN 0272-4332 J9 RISK ANAL JI Risk Anal. PD JUN PY 2000 VL 20 IS 3 BP 377 EP 384 DI 10.1111/0272-4332.203036 PG 8 WC Public, Environmental & Occupational Health; Mathematics, Interdisciplinary Applications; Social Sciences, Mathematical Methods SC Public, Environmental & Occupational Health; Mathematics; Mathematical Methods In Social Sciences GA 414LL UT WOS:000167668100013 ER PT J AU Heron, RJ Lewis, RA Clark, RG Starrett, RP Kane, BE Facer, GR Lumpkin, NE Rickel, DG Pfeiffer, LN West, KW AF Heron, RJ Lewis, RA Clark, RG Starrett, RP Kane, BE Facer, GR Lumpkin, NE Rickel, DG Pfeiffer, LN West, KW TI Cyclotron resonance in undoped, top-gated heterostructures SO SEMICONDUCTOR SCIENCE AND TECHNOLOGY LA English DT Article ID FIELD-EFFECT TRANSISTOR; GAAS-GA1-XALXAS HETEROJUNCTIONS; ELECTRON-MOBILITY; LINEWIDTH; SCATTERING; LIMIT AB We report on cyclotron resonance detected by far-infrared photoconductivity of the two-dimensional electron gas formed in undoped, top-gated GaAs/Al0.3Ga0.7As heterostructures. The photoconductivity method demonstrated here is readily extendable to quantum wires. The top-gated device architecture avoids the disorder inherent in conventional modulation-doped devices and allows precise in situ tuning of carrier density over two orders of magnitude. We observe very sharp resonances (6 mT at 1.5 K) indicating a very high mobility, which is attributed to the low level of impurities. The variation of the linewidth at small filling factor is also consistent with a low concentration of impurities. These results suggest that the filling-factor-dependent oscillations observed in linewidth are not due to the screening of ionized impurities. Filling-factor-dependent oscillations in photoconductivity intensity are also observed, with maxima occurring at even filling factors. C1 Univ Wollongong, Dept Engn Phys, Wollongong, NSW 2522, Australia. Univ New S Wales, Sch Phys, Kensington, NSW 2052, Australia. Univ Calif Los Alamos Natl Lab, NHMFL, Los Alamos, NM 87545 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Heron, RJ (reprint author), Univ Wollongong, Dept Engn Phys, Wollongong, NSW 2522, Australia. RI Lewis, Roger/D-3135-2014 OI Lewis, Roger/0000-0002-4598-7553 NR 15 TC 2 Z9 2 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0268-1242 J9 SEMICOND SCI TECH JI Semicond. Sci. Technol. PD JUN PY 2000 VL 15 IS 6 BP 589 EP 592 DI 10.1088/0268-1242/15/6/318 PG 4 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA 323VK UT WOS:000087585500019 ER PT J AU Gross, AG Harmon, JE Reidy, MS AF Gross, AG Harmon, JE Reidy, MS TI Argument and 17th-century science: A rhetorical analysis with sociological implications SO SOCIAL STUDIES OF SCIENCE LA English DT Article DE hedging; quantification; rhetoric of science; scientific societies; visuals ID ROYAL-SOCIETY; TECHNOLOGY; ARTICLES AB This paper compares the argumentative practices of the English and French scientific communities from the origin of the scientific journal in 1665 up to 1700. To that end, we ask a uniform set of questions related to argumentative practice in a large sample of articles randomly drawn from the three pre-eminent scientific journals of this period: Philosophical Transactions of the Royal Society of London, Journal des Scavans and Memoires de l'Academie Royale des Sciences. The results suggest an interesting link between socio-political structures and their influence on early scientific societies, and the articles in their fledgling publications. In particular, the early professionalization of French science through the Academie Royale led to a heightened emphasis on features familiar in 20th-century practice: quantification, mathematical and mechanical explanations for acquired facts, visual representations of facts and their explanations, and use of observations and experimental results as stepping stones to theory. This social arrangement led as well to a narrower view of what constituted acceptable subject matter. Despite these differences, there are also enough similarities in English and French communicative practices to suggest the beginnings of an international scientific community. C1 Univ Minnesota, Dept Rhetor, St Paul, MN 55108 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Univ Oklahoma, Hist Sci Dept, Norman, OK 73019 USA. RP Gross, AG (reprint author), Univ Minnesota, Dept Rhetor, St Paul, MN 55108 USA. NR 55 TC 9 Z9 11 U1 1 U2 7 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 0306-3127 J9 SOC STUD SCI JI Soc. Stud. Sci. PD JUN PY 2000 VL 30 IS 3 BP 371 EP 396 DI 10.1177/030631200030003002 PG 26 WC History & Philosophy Of Science SC History & Philosophy of Science GA 335XX UT WOS:000088272700002 ER PT J AU Faybishenko, B AF Faybishenko, B TI Tensiometer for shallow and deep measurements of water pressure in vadose zone and groundwater SO SOIL SCIENCE LA English DT Article DE tensiometer; water pressure; deep measurements; groundwater; vadose zone ID SAMPLER AB To measure water pressure at any depth (including depths below 5 to 7 m) in the vadose zone and groundwater, a two-cell, omni-depth tensiometer has been developed. Water level in the lower cell in this tensiometer is maintained at a relatively constant height above the porous tip. An isolated volume of air above the water level in the lower cell changes air pressure in proportion to the water pressure changes of the soils that surround the tensiometer porous tip. The upper cell replenishes water in the lower cell when needed. Several tensiometers can be installed at different depths in boreholes. The air pressure is measured in both cells remotely above the land surface. The tensiometer can be used for long-term monitoring of negative Pressure under drying and wetting cycles in the vadose zone and for monitoring of positive pressure below the water table. This paper describes a tensiometer design and the results of testing the tensiometer models. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Faybishenko, B (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, 1 Cyclotron Rd,MS 90-1116, Berkeley, CA 94720 USA. RI Faybishenko, Boris/G-3363-2015 OI Faybishenko, Boris/0000-0003-0085-8499 NR 29 TC 8 Z9 8 U1 0 U2 4 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0038-075X J9 SOIL SCI JI Soil Sci. PD JUN PY 2000 VL 165 IS 6 BP 473 EP 482 DI 10.1097/00010694-200006000-00003 PG 10 WC Soil Science SC Agriculture GA 327QH UT WOS:000087803900003 ER PT J AU Kurtz, SR Myers, D Townsend, T Whitaker, C Maish, A Hulstrom, R Emery, K AF Kurtz, SR Myers, D Townsend, T Whitaker, C Maish, A Hulstrom, R Emery, K TI Outdoor rating conditions for photovoltaic modules and systems SO SOLAR ENERGY MATERIALS AND SOLAR CELLS LA English DT Article DE photovoltaic; concentrator; DNI; direct irradiance; module; rating; ambient temperature; wind ID PERFORMANCE AB Historically, flat-plate photovoltaic modules have been given a "peak-watt" rating indicating the power generated under 1000 W/m(2) global irradiance at a standard temperature. However, questions have arisen regarding the direct-normal irradiance, ambient or cell temperature, and wind speed (when it is specified) that should be used for evaluating the performance of flat-plate and concentrator modules. By studying the conditions that are observed when the global irradiance on a 2-axis-tracked surface is 1000 W/m(2), our analysis provides an objective, quantitative basis for the choice of the "peak-watt" rating conditions for both types of collectors. These observed conditions are consistent with commonly used values of 850 W/m(2) for direct-normal irradiance and 20 degrees C for ambient temperature. Evidence is given that wind speed should be increased from the commonly used 1 m/s to a more frequently observed 4 m/s. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Endecon Engn, San Ramon, CA 94583 USA. Sandia Natl Labs, Albuquerque, NM 87123 USA. RP Kurtz, SR (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. NR 19 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0248 J9 SOL ENERG MAT SOL C JI Sol. Energy Mater. Sol. Cells PD JUN 1 PY 2000 VL 62 IS 4 BP 379 EP 391 DI 10.1016/S0927-0248(99)00160-9 PG 13 WC Energy & Fuels; Materials Science, Multidisciplinary; Physics, Applied SC Energy & Fuels; Materials Science; Physics GA 325DV UT WOS:000087661800004 ER PT J AU Huh, MY Kim, HC Engler, O AF Huh, MY Kim, HC Engler, O TI Influence of a solution treatment on the evolution of through-thickness texture gradients in dry cold rolled and recrystallized low carbon steel SO STEEL RESEARCH LA English DT Article ID DEEP-DRAWING STEELS; ANNEALING TEXTURES; MICROSTRUCTURE; DEFORMATION; LUBRICATION AB The influence of a solution treatment on the evolution of through-thickness texture gradients in a low carbon steel was studied. In order to intensify through-thickness variations of the strain state, the samples were cold rolled dry, i.e. without lubrication. The evolution of the texture and the microstructure during rolling and recrystallization was tracked by X-ray texture analysis and TEM microstructure investigations. The strain distribution during rolling wars simulated for several layers of the rolled sheets by the finite element method. After the rolling deformation, a specimen taken directly from the hot band showed pronounced through-thickness texture gradients, whereas the solution treated specimen showed a rather uniform rolling texture in all layers analyzed. Analysis of the friction behaviour between the different specimens and the roll material points to a much higher friction between the softer hot band and the rolls. This leads to stronger through-thickness variations in the strain state and, thus, to the pronounced texture gradients observed. The texture gradients in the recrystallized samples reflected those of the as-rolled sheets. In the center layer of the hot band specimen and in all layers of the solution treated specimen characteristic though notably weakened typical plane strain recrystallization textures formed; the textures in outer layers of the hot band sample were even almost random. These weak recrystallization textures could be attributed to the highly inhomogeneous as-deformed microstructure. C1 Korea Univ, Div Engn & Mat Sci, Seoul 136701, South Korea. Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Korea Univ, Div Engn & Mat Sci, Seoul 136701, South Korea. NR 43 TC 10 Z9 10 U1 0 U2 1 PU VERLAG STAHLEISEN MBH PI DUSSELDORF PA SOHNSTRABE 65, D-40237 DUSSELDORF, GERMANY SN 0177-4832 J9 STEEL RES JI Steel Res. PD JUN-JUL PY 2000 VL 71 IS 6-7 BP 239 EP 248 PG 10 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 364DF UT WOS:000089876200009 ER PT J AU Tartakovsky, DM AF Tartakovsky, DM TI Real gas flow through heterogeneous porous media: theoretical aspects of upscaling SO STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT LA English DT Article ID EFFECTIVE PERMEABILITY; HYDRAULIC CONDUCTIVITIES; MOMENTS AB We consider the problem of upscaling transient real gas flow through heterogeneous bounded reservoirs. One of the commonly used methods for deriving effective permeabilities is based on stochastic averaging of nonlinear flow equations. Such an approach, however, would require rather restrictive assumptions about pressure-dependent coefficients. Instead, we use Kirchhoff transformation to linearize the governing stochastic equations prior to their averaging. The linearized problem is similar to that used in stochastic analysis of groundwater flow. We discuss the effects of temporal localization of the nonlocal averaged Darcy's law, as well as boundary effects, on the upscaled gas permeability. Extension of the results obtained by means of small perturbation analysis to highly heterogeneous porous formations is also discussed. C1 Univ Calif Los Alamos Natl Lab, Geoanal Grp, Los Alamos, NM 87545 USA. RP Tartakovsky, DM (reprint author), Univ Calif Los Alamos Natl Lab, Sci Comp Grp, CIC-19,MS B256, Los Alamos, NM 87545 USA. RI Tartakovsky, Daniel/E-7694-2013 NR 31 TC 7 Z9 7 U1 0 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1436-3240 J9 STOCH ENV RES RISK A JI Stoch. Environ. Res. Risk Assess. PD JUN PY 2000 VL 14 IS 2 BP 109 EP 122 DI 10.1007/s004770000031 PG 14 WC Engineering, Environmental; Engineering, Civil; Environmental Sciences; Statistics & Probability; Water Resources SC Engineering; Environmental Sciences & Ecology; Mathematics; Water Resources GA 328LL UT WOS:000087852300003 ER PT J AU Matano, T Koblischka, MR Veal, BW Murakami, M Takizawa, T AF Matano, T Koblischka, MR Veal, BW Murakami, M Takizawa, T TI Superconducting transitions of YBa2Cu3Ox superconductors in high fields SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article; Proceedings Paper CT 2nd International Workshop on the Processing and Applications of Superconducting (RE) BCO Large Grain Materials PASREG) CY OCT 21-22, 1999 CL ICHI YUH KAIKAN IWATE UNIV, MORIOKA, JAPAN SP Ichi Yuh Kaikan Iwate Univ HO ICHI YUH KAIKAN IWATE UNIV ID BA-CU-O; CRYSTALS AB Superconducting transitions were measured in field-cooled cooling and field-cooled warming modes in external magnetic fields ranging between 1 mT and 7 T on YBa2Cu3Ox (Y123) single crystals with and without the fishtail effect. The Y123 crystal with the fishtail effect exhibited a two-step transition when bring cooled in high fields, while the Y123 crystal without the fishtail showed a single step transition. Furthermore, an upturn in magnetic moment was observed at lower temperatures for Y123 with the fishtail effect. Such an upturn is ascribed to the local Cu magnetic moment due to oxygen vacancies. The fishtail effect is thus caused by oxygen vacancies. C1 Nihon Univ, Coll Humanities & Sci, Dept Phys, Setagaya Ku, Tokyo 1560045, Japan. Int Superconduct Technol Ctr, Superconduct Res Lab, Koto Ku, Tokyo 1050023, Japan. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Matano, T (reprint author), Nihon Univ, Coll Humanities & Sci, Dept Phys, Setagaya Ku, 3-25-40 Sakura Josui, Tokyo 1560045, Japan. RI Koblischka, Michael/C-3738-2011 NR 8 TC 2 Z9 2 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD JUN PY 2000 VL 13 IS 6 BP 805 EP 806 DI 10.1088/0953-2048/13/6/336 PG 2 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 326YT UT WOS:000087765400037 ER PT J AU Hull, JR AF Hull, JR TI Effect of permanent-magnet irregularities in levitation force measurements SO SUPERCONDUCTOR SCIENCE & TECHNOLOGY LA English DT Article; Proceedings Paper CT 2nd International Workshop on the Processing and Applications of Superconducting (RE) BCO Large Grain Materials PASREG) CY OCT 21-22, 1999 CL ICHI YUH KAIKAN IWATE UNIV, MORIOKA, JAPAN SP Ichi Yuh Kaikan Iwate Univ HO ICHI YUH KAIKAN IWATE UNIV ID SUPERCONDUCTORS AB In the measurement of the levitation force between a vertically magnetized permanent magnet (PM) and a bulk high-temperature superconductor (HTS), PM domains with horizontal components of magnetization are shown to produce a non-negligible contribution to the levitation force in most systems. Such domains are typically found in all PMs, even in those that exhibit zero net horizontal magnetic moment. Extension of this analysis leads to an HTS analogue of Earnshaw's theorem, in which the vertical stiffness is equal to the sum of the horizontal stiffness at the field-cooling position, independent of the angular distribution of magnetic moments within the PM. C1 Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Hull, JR (reprint author), Argonne Natl Lab, Div Energy Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 14 TC 9 Z9 9 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-2048 J9 SUPERCOND SCI TECH JI Supercond. Sci. Technol. PD JUN PY 2000 VL 13 IS 6 BP 854 EP 856 DI 10.1088/0953-2048/13/6/347 PG 3 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 326YT UT WOS:000087765400048 ER PT J AU Goncharov, AA Protsenko, IM Yushkov, GY Monteiro, OR Brown, IG AF Goncharov, AA Protsenko, IM Yushkov, GY Monteiro, OR Brown, IG TI High-dose ion implantation using a high-current plasma lens SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 11th International Conference on Surface Modification of Metals by Ion Beams (SMMIB-99) CY SEP 19-24, 1999 CL BEIJING, PEOPLES R CHINA SP Beijing Normal Univ, Tsinghua Univ, Chinese Acad Sci, Shanghai Inst Met, Chinese Mat Res Soc DE ion beams; plasma lens; beam focussing; ion implantation; materials synthesis; surface modification ID CHARGE-STATE DISTRIBUTIONS; BEAMS AB A high-current plasma lens has been used to focus a large area energetic ion beam and thereby to increase the ion current density by a factor of up to 30, providing a convenient, simple and quick way of carrying out high-dose ion implantation. Here we review the characteristics and performance of the plasma lens, and describe demonstration experiments in which broad beams of carbon and cobalt ions (separately), formed from a vacuum are ion source, were implanted into silicon test substrates. The carbon implantation was done at an ion energy of 30 keV and to a dose of 5 x 10(17) cm(-2), and the cobalt implantation was done at a mean Co ion energy of 50 keV and to a dose of 2 x 10(17) cm(-2). The carbon-implanted samples were annealed in an inert atmosphere to produce epitaxial beta-SiC, and the cobalt-implanted samples were annealed to produce polycrystalline CoSi2. The recrystallization reactions were monitored using X-ray diffraction. The experiments demonstrate that high-current ion beams can be focused by a plasma lens in this way, providing a tool for compressing the ion beam current density by over an order of magnitude. The plasma lens offers a relatively simple ion beam tool for applications calling for high-implanted ion concentrations. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Russian Acad Sci, Inst High Current Elect, Tomsk 634055, Russia. NASU, Inst Phys, UA-252650 Kiev, Ukraine. RP Brown, IG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Bldg 53, Berkeley, CA 94720 USA. RI Yushkov, Georgy/O-8024-2015 OI Yushkov, Georgy/0000-0002-7615-6058 NR 12 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD JUN-JUL PY 2000 VL 128 BP 15 EP 20 DI 10.1016/S0257-8972(00)00637-X PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 329FY UT WOS:000087897500004 ER PT J AU Zhang, T Tang, BY Zeng, ZM Chen, QC Tian, XB Kwok, TK Chu, PK Monteiro, OR Brown, IG AF Zhang, T Tang, BY Zeng, ZM Chen, QC Tian, XB Kwok, TK Chu, PK Monteiro, OR Brown, IG TI Macro-particle free metal plasma immersion ion implantation and/or deposition in a multifunctional configuration SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 11th International Conference on Surface Modification of Metals by Ion Beams (SMMIB-99) CY SEP 19-24, 1999 CL BEIJING, PEOPLES R CHINA SP Beijing Normal Univ, Tsinghua Univ, Chinese Acad Sci, Shanghai Inst Met, Chinese Mat Res Soc DE metal plasma; ion beam assisted deposition; plasma immersion ion implantation ID DIAMOND-LIKE CARBON; CATHODIC ARC; FILMS; TRANSPORT AB For high-dose metal ion implantation, the use of plasma immersion offers the high-rate advantage, but the simultaneous formation of a surface film along with the sub-surface implanted layer is sometimes a detriment. In this work, we describe a metal plasma immersion approach in which pure and macro-particle free implantation (metal and/or gas ions), pure deposition without ion implantation, or dynamic metal ion beam assisted deposition and gaseous plasma immersion ion implantation (DIBAD metal and gas plasma immersion) can be obtained. We have demonstrated the technique by carrying out Ti and Ta implantation at approximately 80 keV (Ti) and 120 keV (Ta) and doses on the order of 1 X 10(17) ions/cm(2). In our experiments, the Ta and Ti plasma immersion process can be tuned to give rise to implantation solely with no concomitant surface film formation. The atomic fraction of the applied dose that deposits as a him vs. the part that is energetically implanted during the DIBAD of metal and gas plasma immersion can be precisely controlled. This is a valuable method to fabricate advanced materials. (C) 2000 Elsevier Science S.B. All rights reserved. C1 City Univ Hong Kong, Dept Phys & Mat Sci, Kowloon, Hong Kong, Peoples R China. Beijing Normal Univ, Ctr Radiat, Inst Low Energy Nucl Phys, Beijing 100875, Peoples R China. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Chu, PK (reprint author), City Univ Hong Kong, Dept Phys & Mat Sci, 83 Tat Chee Ave, Kowloon, Hong Kong, Peoples R China. EM paul.chu@cityu.edu.hk RI Chu, Paul/B-5923-2013 OI Chu, Paul/0000-0002-5581-4883 NR 28 TC 11 Z9 11 U1 1 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD JUN-JUL PY 2000 VL 128 BP 231 EP 235 DI 10.1016/S0257-8972(00)00653-8 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 329FY UT WOS:000087897500042 ER PT J AU Salvadori, MC Cattani, M Vizir, A Monteiro, OR Yu, KM Brown, IG AF Salvadori, MC Cattani, M Vizir, A Monteiro, OR Yu, KM Brown, IG TI Metal ion mixing in diamond SO SURFACE & COATINGS TECHNOLOGY LA English DT Article; Proceedings Paper CT 11th International Conference on Surface Modification of Metals by Ion Beams (SMMIB-99) CY SEP 19-24, 1999 CL BEIJING, PEOPLES R CHINA SP Beijing Normal Univ, Tsinghua Univ, Chinese Acad Sci, Shanghai Inst Met, Chinese Mat Res Soc DE ion mixing; ion implantation; thin films; diamond films; ion beams ID DEPOSITION AB We have carried out some investigations of the mixing of thin metal films into diamond by energetic metal ion bombardment. Free-standing diamond films were made by microwave plasma-assisted CVD, onto which films of Nb or Ta, approximately 100 Angstrom thick, were deposited using a filtered vacuum are plasma technique. The metalized diamond was then bombarded with a Ta and Nb ion beam, respectively, at an energy of 150 keV and to an applied dose of similar to 7 x 10(16) ions/cm(2). The Nb and Ta depth profiles were measured by 2 MeV He+ Rutherford backscattering spectrometry. Intense intermixing was produced between the original metal overlay, the diamond matrix, and the implanted atoms; and the concentration depth profiles were found to be well-described by the predictions of the TRIM code. Here, we outline the techniques used for diamond synthesis and the preparation of free-standing films. the vacuum are plasma deposition of Nb and Ta thin films, and the Ta and Nb ion implantations; and we describe our observations of the ion-mixed films formed in this way. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Sao Paulo, Inst Phys, BR-05315970 Sao Paulo, SP, Brazil. High Current Elect Inst, Tomsk 634050, Russia. RP Brown, IG (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Yu, Kin Man/J-1399-2012; Cattani, Mauro/N-9749-2013; Salvadori, Maria Cecilia/A-9379-2013; Vizir, Alexey/R-2139-2016 OI Yu, Kin Man/0000-0003-1350-9642; Vizir, Alexey/0000-0002-9563-8650 NR 19 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD JUN-JUL PY 2000 VL 128 BP 375 EP 380 DI 10.1016/S0257-8972(00)00607-1 PG 6 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 329FY UT WOS:000087897500069 ER PT J AU Kundakovic, L Mullins, DR Overbury, SH AF Kundakovic, L Mullins, DR Overbury, SH TI Adsorption and reaction of H2O and CO on oxidized and reduced Rh/CeOx(111) surfaces SO SURFACE SCIENCE LA English DT Article DE carbon monoxide; cerium; chemisorption; rhodium; soft X-ray photoelectron spectroscopy; thermal desorption; water ID GAS-SHIFT REACTION; TRANSFORM INFRARED-SPECTROSCOPY; CERIUM OXIDE; OXYGEN MIGRATION; ROOM-TEMPERATURE; CARBON-MONOXIDE; WATER; RH; CATALYSTS; CEO2 AB The interaction of H2O and CO with thin films of highly oriented CeO2(111) with vapor deposited Rh was studied using soft X-ray photoemission spectroscopy and thermal desorption spectroscopy. Adsorbed surface states of CO and H2O and desorption products were identified in relation with the ceria substrate oxidation state, adsorption/annealing temperature and the presence of Rh. Only molecularly adsorbed H2O and CO were detected on Rh/oxidized ceria surfaces. Rh/reduced ceria surfaces are more reactive, and promote dissociation of both H2O and CO. CO is preferentially adsorbed on the metal and H2O on the ceria substrate. Two adsorbed states were identified following the low temperature water adsorption on Rh/reduced ceria, chemisorbed water and hydroxyls. In the absence of Rh, chemisorbed water desorbs below 300 K and hydroxyls decompose above 500 K to give H-2 as a desorption product. Rh promotes the dissociation of chemisorbed water and formation of hydrogen in the 200-350 K temperature range. It also lowers the temperature of hydrogen formation from hydroxyls. The interaction of CO and H2O strongly depends on the ceria oxidation state. Reaction of atomic carbon (formed by CO dissociation) with oxygen from ceria is facilitated by the presence of coadsorbed water. On the other hand, hydrogen desorption is inhibited by the presence of coadsorbed CO. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Overbury, SH (reprint author), Oak Ridge Natl Lab, POB 2008,Bldg 4500N,MS 6201, Oak Ridge, TN 37831 USA. RI Overbury, Steven/C-5108-2016 OI Overbury, Steven/0000-0002-5137-3961 NR 32 TC 102 Z9 105 U1 5 U2 51 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 1 PY 2000 VL 457 IS 1-2 BP 51 EP 62 DI 10.1016/S0039-6028(00)00332-0 PG 12 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 325XW UT WOS:000087703000018 ER PT J AU Jirsak, T Kuhn, M Rodriguez, JA AF Jirsak, T Kuhn, M Rodriguez, JA TI Chemistry of NO2 on Mo(110): decomposition reactions and formation of MoO2 SO SURFACE SCIENCE LA English DT Article DE ab initio quantum chemical methods and calculations; molybdenum; molybdenum oxides; nitrogen oxides; surface chemical reaction; synchrotron radiation photoelectron spectroscopy ID NITROGEN-DIOXIDE; NITRIC-OXIDE; ELECTRONIC-PROPERTIES; THERMAL-DESORPTION; ATOMIC OXYGEN; ADSORPTION; SURFACES; OXIDATION; PHOTOEMISSION; FILMS AB Synchrotron-based high-resolution photoemission and ab initio self-consistent field (SCF) calculations have been used to study the chemistry of nitrogen dioxide on Mo(110). The Mo surface reacts readily with nitrogen dioxide, decomposing the molecule into adsorbed NO and O adatoms at temperatures between 100 and 150 K. The majority of the NO produced further dissociates (NOads-->N-ads+O-ads) between 250 and 350 K. Dosing of NO2 at 300 K leads to full decomposition of the molecule and in addition O is deposited on the Mod(110) surface by the reaction: NO2,gas-->NOgas+O-ads. Two important factors make easy the dissociation of NO2 on Mo(110). The first one is a transfer of electrons from the metal into the 6a(1) orbital of NO2 that weakens the bonds within the molecule. The second one is the very large stability of the N and O atoms on Mo(110). The ab initio SCF calculations predict that on Mo(110) nitrogen dioxide probably adopts eta(2)-O,O or eta(2)-N,O bonding configurations as precursors for dissociation of the molecule, Molybdenum has a larger ability to cleavage N-O bonds than late transition metals (Rh, Pt, Pd, Ag, Au) but a lower ability than W. At high temperatures (similar to 1000 K), the reaction of NO2 with Mo(110) produces pure films (thickness > 20 Angstrom) of polycrystalline MoO2. Nitrogen dioxide is a much better oxidizing agent than molecular oxygen. The MoO2 films are good models for studying the chemical properties of molybdenum oxide surfaces, and can be used in the synthesis of Al2O3 (2Al + 1.5MoO(2)-->Al2O3 + 1.5Mo) or mixed-metal oxide systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 60 TC 35 Z9 36 U1 0 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 1 PY 2000 VL 457 IS 1-2 BP 254 EP 266 DI 10.1016/S0039-6028(00)00381-2 PG 13 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 325XW UT WOS:000087703000033 ER PT J AU Charlton, G Brennan, S Muryn, CA McGrath, R Norman, D Turner, TS Thornton, G AF Charlton, G Brennan, S Muryn, CA McGrath, R Norman, D Turner, TS Thornton, G TI Surface relaxation of SrTiO3(001) SO SURFACE SCIENCE LA English DT Article DE low index single crystal surfaces; titanium oxide; X-ray scattering, diffraction, and reflection ID X-RAY-DIFFRACTION; SCATTERING; RECONSTRUCTION AB Surface X-ray diffraction has been used to examine the 300 K structure of SrTiO3(001) 1 x 1 with a termination of 78% TiO and 22% SrO. The data indicate that a lateral ferroelectric distortion is absent on both terminations, consistent with a recent theoretical calculation. Although the negligible Ti atom relaxation found on the TiO termination is consistent with medium-energy ion scattering data, it differs from recent density functional theory calculations by 0.13 and 0.16 Angstrom. Zn contrast, the Sr displacement towards the SrO surface of 0.22 +/- 0.07 Angstrom is in good agreement with theory. (C) 2000 Elsevier Science B.V, All rights reserved. C1 Univ Manchester, Surface Sci Res Ctr, Manchester M13 9PL, Lancs, England. Univ Manchester, Dept Chem, Manchester M13 9PL, Lancs, England. SLAC, SSRL, Stanford, CA 94309 USA. Univ Liverpool, Surface Sci Res Ctr, Liverpool L69 3BX, Merseyside, England. Univ Liverpool, Dept Phys, Liverpool L69 3BX, Merseyside, England. CLRC, Daresbury Lab, Warrington WA4 4AD, Cheshire, England. RP Thornton, G (reprint author), Univ Manchester, Surface Sci Res Ctr, Manchester M13 9PL, Lancs, England. RI McGrath, Ronan/A-1568-2009 OI McGrath, Ronan/0000-0002-9880-5741 NR 22 TC 72 Z9 72 U1 1 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 1 PY 2000 VL 457 IS 1-2 BP L376 EP L380 DI 10.1016/S0039-6028(00)00403-9 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 325XW UT WOS:000087703000007 ER PT J AU Haas, H Wang, CZ Ho, KM Fahnle, M Elsasser, C AF Haas, H Wang, CZ Ho, KM Fahnle, M Elsasser, C TI Reconstruction of the Mo(100) surface: a tight-binding study SO SURFACE SCIENCE LA English DT Article DE low index single crystal surfaces; metallic surfaces; molybdenum; semi-empirical models and model calculations; surface electronic phenomena (work function, surface potential, surface states, etc.) ID MO(001) SURFACE; PHASE; MODEL; TRANSITION; MOLYBDENUM; SCATTERING AB The Mo (100) surface is investigated by our recently developed environment-dependent tight-binding model. The predicted reconstruction pattern is similar to that observed in diffraction experiments. The driving mechanism underlying the surface reconstruction is investigated and the role of the electronic structure is discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Max Planck Inst Met Forsch, D-70569 Stuttgart, Germany. Max Planck Inst Met Forsch, D-70174 Stuttgart, Germany. RP Wang, CZ (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 16 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD JUN 1 PY 2000 VL 457 IS 1-2 BP L397 EP L403 DI 10.1016/S0039-6028(00)00412-X PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 325XW UT WOS:000087703000011 ER PT J AU Rodriguez, JA Dvorak, J Jirsak, T AF Rodriguez, JA Dvorak, J Jirsak, T TI Chemistry of thiophene on Mo(110), MoCx and MoSx surfaces: photoemission studies SO SURFACE SCIENCE LA English DT Article DE aromatics; carbides; molybdenum; sulphides; sulphur; surface chemical reaction; synchrotron radiation photoelectron spectroscopy ID SUPPORTED MOLYBDENUM CARBIDE; NITRIDE CATALYSTS; ADSORPTION; SULFUR; METAL; HYDRODESULFURIZATION; DESULFURIZATION; PHOTOELECTRON; SPECTROSCOPY; HYDROGEN AB Synchrotron-based high resolution photoemission has been used to study the adsorption and decomposition of thiophene on clean Mo(110) and carbide- or sulfide-modified molybdenum (MoCx and MoSx, respectively). Thiophene adsorbs molecularly on Mo(110) at 100 K. By 180 K, upon desorption of the thiophene multilayer, chemisorbed thiophene and its decomposition products (S and CxHy fragments) coexist on the Mo(110) surface. At 250 K, no C-S bonds are left. There is a continuous transformation of the CxHy species into atomic C at temperatures between 300 and 600 K. The chemistry of thiophene on clean and carbide-modified molybdenum is very similar. In contrast, MoSx is less reactive than Mo(110) or MoCx, even after introducing a large number of sulfur vacancies in the sulfide or after promoting it with nickel. Thiophene does not dissociate on MoSx or Ni/MoSx. The differences in chemical reactivity between MoSx and MoCx correlate well with changes in the electronic properties of Mo in these systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11953 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11953 USA. NR 36 TC 49 Z9 51 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 JUN 1 PY 2000 VL 457 IS 1-2 BP L413 EP L420 DI 10.1016/S0039-6028(00)00416-7 PG 8 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 325XW UT WOS:000087703000013 ER PT J AU Pilat, JF AF Pilat, JF TI The nuclear turning point: A blueprint for deep cuts and de-alerting of nuclear weapons SO SURVIVAL LA English DT Book Review C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Pilat, JF (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0039-6338 J9 SURVIVAL JI Survival PD SUM PY 2000 VL 42 IS 2 BP 181 EP 182 PG 2 WC International Relations; Political Science SC International Relations; Government & Law GA 334DP UT WOS:000088170700013 ER PT J AU List, EJW Partee, J Shinar, J Scherf, U Mullen, K Zojer, E Graupner, W Leising, G AF List, EJW Partee, J Shinar, J Scherf, U Mullen, K Zojer, E Graupner, W Leising, G TI Solid state effects in the electronic structure of ladder-type poly(p-phenylene)s and oligo(p-phenylene)s SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT 2nd International Conference on Electroluminescene of Molecular Materials and Related Phenomena (ICEL-2) CY MAY 15-18, 1999 CL SHEFFIELD, ENGLAND SP Univ Sheffield, Dept Phys & Astronomy, Electr & Photon Mol Mat Grp DE polymer; photoluminescence; photoluminescence-detected magnetic resonance ID DETECTED MAGNETIC-RESONANCE; LIGHT-EMITTING-DIODES; CONJUGATED POLYMER; STIMULATED-EMISSION; OLIGOMERS; ELECTROLUMINESCENCE; SPECTROSCOPY; ABSORPTION; POLARONS; FILMS AB In this paper, the spin-dependent photophysical properties of poly(para-phenylene)-type ladder-polymers (LPPP), a highly luminescent polymer with emission yields of similar to 30% in film and similar to 100% in solution, and of five- and seven-member ladder-type oligo( para-phenylenes) (LOPP5 and LOPP7, respectively) are determined via their photoluminescence (PL) emission, PL excitation, and PL-detected magnetic resonance (PLDMR) spectra. In the latter experiment, we investigated spin-sensitive properties, such as the formation of polaron pairs as a function of conjugation length and interchain interaction. The observation of a PLDMR quenching resonance upon increasing the temperature and/or the excitation wavelength is discussed in relation with the formation of polarons and polaron pairs from delocalized and localized states, respectively. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Graz Tech Univ, Inst Festkorperphys, A-8010 Graz, Austria. Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. Max Planck Inst Polymerforsch, Mainz, Germany. Virginia Tech, Dept Phys, Blacksburg, VA 24060 USA. RP List, EJW (reprint author), Graz Tech Univ, Inst Festkorperphys, Petersgasse 16, A-8010 Graz, Austria. RI Zojer, Egbert/B-3265-2010; Scherf, Ullrich/G-1552-2012; List-Kratochvil, Emil/M-5312-2013 OI Zojer, Egbert/0000-0002-6502-1721; NR 21 TC 7 Z9 7 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 1 PY 2000 VL 111 BP 509 EP 513 DI 10.1016/S0379-6779(99)00429-4 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 322EB UT WOS:000087496300116 ER PT J AU Gadermaier, C List, EJW Markart, P Graupner, W Partee, J Shinar, J Smith, R Gin, D Leising, G AF Gadermaier, C List, EJW Markart, P Graupner, W Partee, J Shinar, J Smith, R Gin, D Leising, G TI Photophysical studies on nanostructured PPV-systems SO SYNTHETIC METALS LA English DT Article; Proceedings Paper CT 2nd International Conference on Electroluminescene of Molecular Materials and Related Phenomena (ICEL-2) CY MAY 15-18, 1999 CL SHEFFIELD, ENGLAND SP Univ Sheffield, Dept Phys & Astronomy, Electr & Photon Mol Mat Grp DE superlattices; poly(phenylene vinylene) and derivatives; photoinduced absorption ID ABSORPTION; POLYMER; STATES AB We have used continuous wave photoinduced absorption (PIA) to probe the (spin-1/2) polaron and (spin-l) triplet excitations in bulk poly( para-phenylene vinylene) (PPV) films and isolated PPV chains incorporated into a self-assembled matrix ordered at the nanometer scale (nano-PPV). The ordering is a result of the lyotropic liquid crystalline character of the matrix material. We investigated the influence of the chain isolation on the transition energies and the effect of the resulting one-dimensionality on the excitation dynamics. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Graz Tech Univ, Inst Festkorperphys, A-8010 Graz, Austria. Virginia Tech, Dept Phys, Blacksburg, VA 24060 USA. Iowa State Univ Sci & Technol, Ames Lab, US DOE, Ames, IA 50011 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Gadermaier, C (reprint author), Graz Tech Univ, Inst Festkorperphys, Petersgasse 16, A-8010 Graz, Austria. RI Gadermaier, Christoph/O-4834-2016; List-Kratochvil, Emil/M-5312-2013; OI Gadermaier, Christoph/0000-0001-6613-9644; GIN, DOUGLAS/0000-0002-6215-668X NR 12 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0379-6779 J9 SYNTHETIC MET JI Synth. Met. PD JUN 1 PY 2000 VL 111 BP 523 EP 526 DI 10.1016/S0379-6779(99)00411-7 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter; Polymer Science SC Materials Science; Physics; Polymer Science GA 322EB UT WOS:000087496300119 ER PT J AU Jiang, W Nadeau, G Zaghib, K Kinoshita, K AF Jiang, W Nadeau, G Zaghib, K Kinoshita, K TI Thermal analysis of the oxidation of natural graphite - effect of particle size SO THERMOCHIMICA ACTA LA English DT Article DE graphite; oxidation; thermal; active sites; particle size ID STRUCTURAL PARAMETERS; CARBON; COAL; CHARS; AIR AB The oxidation of natural graphite particles with a prismatic (flake-like) structure was investigated by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The objective of this study is to examine the relationship between the relative fraction of edge sites and the oxidation behaviour of graphite. The approximate prismatic structure of the natural graphite provided a model geometry from which the relative fraction of edge and basal plane sites was determined. The three thermal parameters, ignition temperature (T(i)), temperature maximum (T(m)) in the DTA curves, and the temperature at which 15 % carbon weight loss is attained (T(15)), were determined for a series of natural graphite samples (average particle size, 2-40 mu m) using simultaneous TGA/DTA. The results reported in this study support the observation that the fraction of edge sites has a strong influence on the thermal parameters (T(i), T(m) and T(15)) for the oxidation of graphite. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Inst Rech Hydro Quebec, Varennes, PQ J3X 1S1, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. RP Zaghib, K (reprint author), Inst Rech Hydro Quebec, 1800 Boul Lionel Boulet, Varennes, PQ J3X 1S1, Canada. EM karimz@ireq.ca NR 27 TC 76 Z9 79 U1 3 U2 16 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD JUN 1 PY 2000 VL 351 IS 1-2 BP 85 EP 93 DI 10.1016/S0040-6031(00)00416-0 PG 9 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 317YW UT WOS:000087255800013 ER PT J AU Corley, RA English, JC Hill, TS Fiorica, LA Morgott, DA AF Corley, RA English, JC Hill, TS Fiorica, LA Morgott, DA TI Development of a physiologically based pharmacokinetic model for hydroquinone SO TOXICOLOGY AND APPLIED PHARMACOLOGY LA English DT Article DE hydroquinone; PBPK model; renal toxicity; glutathione conjugates ID SPRAGUE-DAWLEY RATS; BENZENE METABOLITES; HUMAN LIVER; TOXICITY; MICE; GLUTATHIONE; BIOTRANSFORMATION; 2-BUTOXYETHANOL; NEPHROTOXICITY; IDENTIFICATION AB Hydroquinone (HQ) produces nephrotoxicity and renal tubular adenomas in male F344 rats following 2 years of oral dosing. Female F344 and SD rats are comparatively resistant to these effects. Nephrotoxicity and tumorigenicity have been associated with a minor glutathione conjugation pathway following the oxidation of HQ to benzoquinone (BQ), The majority of administered doses (90-99%) consists of glucuronide and sulfate conjugates of HQ. An initial physiologically based pharmacokinetic model was developed to characterize the role of kinetics in the strain differences observed in HQ-induced renal toxicity and tumorigenicity. Partition coefficients, protein-binding, and metabolic rate constants were determined directly or estimated from a series of in vivo and in vitro studies. Metabolism was confined to the liver and GI tract, The total flux through the glutathione pathway represented the "internal dose" of HQ for nephrotoxicity. Simulations were compared to a variety of data from male and female F344 rats, male SD rats, and a single male human volunteer. Simulations of intraperitoneal administration resulted in higher amounts of glutathione conjugates than comparable oral doses. This was consistent with protein-binding and toxicity studies and emphasized the importance of first-pass GI tract metabolism. In addition, male F344 rats were predicted to form more total glutathione conjugates than SD rats at equivalent dose levels, which was also consistent with the observed strain differences in renal toxicity, This model represents the first stage in the development of a biologically based dose-response model for improving the scientific basis for human health risk assessments of HQ. (C) 2000 Academic Press. C1 Battelle Mem Inst, Pacific NW Div, Mol Biosci Dept, Richland, WA 99352 USA. Eastman Kodak Co, Hlth & Environm Labs, Rochester, NY 14652 USA. RP Corley, RA (reprint author), Battelle Mem Inst, Pacific NW Div, Mol Biosci Dept, POB 999,P7-59, Richland, WA 99352 USA. NR 39 TC 21 Z9 21 U1 0 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0041-008X J9 TOXICOL APPL PHARM JI Toxicol. Appl. Pharmacol. PD JUN 1 PY 2000 VL 165 IS 2 BP 163 EP 174 DI 10.1006/taap.2000.8909 PG 12 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 327KN UT WOS:000087793200007 PM 10828212 ER PT J AU Wilson, KB Baldocchi, DD Hanson, PJ AF Wilson, KB Baldocchi, DD Hanson, PJ TI Quantifying stomatal and non-stomatal limitations to carbon assimilation resulting from leaf aging and drought in mature deciduous tree species SO TREE PHYSIOLOGY LA English DT Article DE A/C-i curve; leaf age; maple; oak; photosynthetic limitations; stomata ID NONSTOMATAL LIMITATIONS; CO2 ASSIMILATION; PHOTOSYNTHETIC PARAMETERS; NET PHOTOSYNTHESIS; SEASONAL PATTERNS; WATER-STRESS; CONDUCTANCE; LEAVES; MODEL; OAK AB Gas exchange techniques were used to investigate light-saturated carbon assimilation and its stomatal and nonstomatal limitations over two seasons in mature trees of five species in a closed deciduous forest. Stomatal and non-stomatal contributions to decreases in assimilation resulting from leaf age and drought were quantified relative to the maximum rates obtained early in the season at optimal soil water contents. Although carbon assimilation, stomatal conductance and photosynthetic capacity (V-cmax) decreased with leaf age, decreases in V-cmax accounted for about 75% of the leaf-age related reduction in light-saturated assimilation rates, with a secondary role for stomatal conductance (around 25%). However, when considered independently from leaf age, the drought response was dominated by stomatal limitations, accounting for about 75% of the total limitation. Some of the analytical difficulties associated with computing limitation partitioning are discussed, including path dependence, patchy stomatal closure and diffusion in the mesophyll. Although these considerations may introduce errors in our estimates, our analysis establishes some reasonable boundaries on relative limitations and shows differences between drought and non-drought years. Estimating seasonal limitations under natural conditions, as shown in this study, provides a useful basis for comparing limitation processes between years and species. C1 NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Wilson, KB (reprint author), NOAA, Atmospher Turbulence & Diffus Div, POB 2456, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011; Kodama, Naomi/D-9553-2011; Baldocchi, Dennis/A-1625-2009 OI Hanson, Paul J./0000-0001-7293-3561; Kodama, Naomi/0000-0001-9913-9886; Baldocchi, Dennis/0000-0003-3496-4919 NR 44 TC 108 Z9 112 U1 2 U2 24 PU HERON PUBLISHING PI VICTORIA PA 202, 3994 SHELBOURNE ST, VICTORIA, BC V8N 3E2, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD JUN PY 2000 VL 20 IS 12 BP 787 EP 797 PG 11 WC Forestry SC Forestry GA 334RY UT WOS:000088200500002 ER PT J AU Gibson, JM Treacy, MMJ Voyles, PM AF Gibson, JM Treacy, MMJ Voyles, PM TI Atom pair persistence in disordered materials from fluctuation microscopy SO ULTRAMICROSCOPY LA English DT Article ID ELECTRON-MICROSCOPY; AMORPHOUS MATERIALS; RANGE ORDER; COHERENCE; SILICON AB We show that the kinematical theory of fluctuation microscopy for a disordered specimen can be reformulated in terms of an atom pair-pair correlation function. Resolution and coherence are two experimental variables which yield a two-dimensional fluctuation map. This map is a transformation of the pair-pair correlation function, but can be directly interpreted in terms of a pair persistence function (PPF). We show that the PPF reveals the correlation length and structure for a simple paracrystalline model. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 NEC Res Inst, Princeton, NJ 08540 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. CNRS, Ctr Etud Chim Met, F-94407 Vitry, France. Argonne Natl Lab, Argonne, IL 60439 USA. RP Treacy, MMJ (reprint author), NEC Res Inst, 4 Independence Way, Princeton, NJ 08540 USA. RI Gibson, Murray/E-5855-2013; OI Gibson, Murray/0000-0002-0807-6224; Voyles, Paul/0000-0001-9438-4284 NR 22 TC 69 Z9 69 U1 0 U2 13 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3991 J9 ULTRAMICROSCOPY JI Ultramicroscopy PD JUN PY 2000 VL 83 IS 3-4 BP 169 EP 178 DI 10.1016/S0304-3991(00)00013-9 PG 10 WC Microscopy SC Microscopy GA 317LN UT WOS:000087227000004 ER PT J AU Garten, CT AF Garten, CT TI Nitrogen saturation and soil N availability in a high-elevation spruce and fir forest SO WATER AIR AND SOIL POLLUTION LA English DT Article DE elevation gradient; Great Smoky Mountains National Park; nitrification; particulate organic matter; soil N mineralization; topography ID SOUTHERN APPALACHIAN MOUNTAINS; GREAT SMOKY MOUNTAINS; N-15 ABUNDANCE; DEPOSITION; ECOSYSTEMS; DYNAMICS; MINERALIZATION; THROUGHFALL; CHEMISTRY; GRADIENT AB A field study was conducted during the summer of 1995 to gain a better understanding of the causes of nitrate (NO3-N) leaching and ongoing changes in soil nitrogen (N) availability in high-elevation (1524-2000 m) spruce (Picea rubens) and fir (Abies fraseri) forests of the Great Smoky Mountains National Park, Tennessee and North Carolina, U.S.A. Indicators of soil N availability (total soil N concentrations, extractable NH4-N, extractable NO3-N, and C/N ratios) were measured in Oa and A horizons at 33 study plots. Dynamic measures included potential net soil N mineralization determined in 12-week aerobic laboratory incubations at 22 degrees C. Potential net nitrification in the A horizon was correlated (r = +0.83, P < 0.001) with total soil N concentrations. Most measures of soil N availability did not exhibit significant trends with elevation, but there were topographic differences. Potential net soil N mineralization and net nitrification in the A horizon were higher in coves than on ridges. Relative amounts of particulate and organomineral soil organic matter influenced potential net N mineralization and nitrification in the A horizon. Calculations indicate that soil N availability and NO3-N leaching in high-elevation spruce and fir forests of the Great Smoky Mountains National Park will increase in response to regional warming. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Garten, CT (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 41 TC 7 Z9 8 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD JUN PY 2000 VL 120 IS 3-4 BP 295 EP 313 DI 10.1023/A:1005270012802 PG 19 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 314TA UT WOS:000087072600008 ER PT J AU Freifeld, BM Oldenburg, CM AF Freifeld, BM Oldenburg, CM TI Restricted interval Guelph permeameter: Theory and application SO WATER RESOURCES RESEARCH LA English DT Article ID SATURATED HYDRAULIC CONDUCTIVITY; HEAD WELL PERMEAMETER; LINEAR POINT-SOURCE; HAPPENS AB A constant head permeameter system has been developed for use in small diameter boreholes with any orientation, It is based upon the original Guelph permeameter concept of using a Mariotte siphon reservoir to control the applied head. The new tool, called a Restricted Interval Guelph (RIG) permeameter uses either a single pneumatic packer or straddle packer to restrict the area through which water is allowed to flow so that the borehole wetted area is independent of the applied head. The RIG permeameter has been used at Yucca Mountain, Nevada, in the nonwelded rhyolitic Paintbrush Tuff. Analysis of the acquired data is based upon saturated-unsaturated flow theory that relies upon the quasi-linear approximation to estimate field-saturated hydraulic conductivity (K-fs) and the alpha parameter (sorptive number) of the exponential relative hydraulic conductivity-pressure head relationship. These results are compared with a numerical model based upon the solution of the Richards equation using a van Genuchten capillary pressure-saturation formulation. The numerical model incorporates laboratory capillary pressure versus saturation functions measured from cores taken from nearby boreholes. Comparison between the analytical and numerical approaches shows that the simple analytic model is valid for analyzing the data collected. Sensitivity analysis performed with the numerical model shows that the RIG permeameter is an effective tool for estimating permeability and sorptive number for the nonwelded Paintbrush Tuff. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Freifeld, BM (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, MS 90-1116, Berkeley, CA 94720 USA. RI Freifeld, Barry/F-3173-2010; Oldenburg, Curtis/L-6219-2013 OI Oldenburg, Curtis/0000-0002-0132-6016 NR 18 TC 4 Z9 4 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 2000 VL 36 IS 6 BP 1373 EP 1380 DI 10.1029/2000WR900034 PG 8 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 317LL UT WOS:000087226800001 ER PT J AU Webb, SW AF Webb, SW TI A simple extension of two-phase characteristic curves to include the dry region SO WATER RESOURCES RESEARCH LA English DT Article ID SOIL-WATER RETENTION; PARAMETRIC MODELS; IMMISCIBLE FLUIDS; CONSISTENT SET; 2-PHASE FLOW; OVEN DRYNESS; EQUATION; ADSORPTION; SUBSURFACE; SATURATION AB Two-phase characteristic curves are necessary for the simulation of water and vapor flow in porous media. Existing functions such as van Genuchten [1980], Brooks and Corey, [1966], and Luckner et al. [1989] have significant limitations in the dry region as the liquid saturation goes to zero. This region, which is important in a number of applications; including liquid and vapor flow and vapor-solid sorption, has been the subject of a number of previous investigations. Most previous studies extended standard capillary pressure curves into the adsorption region to zero water content and required a refitting of the revised curves to the data. In contrast, the present method provides for a simple extension of existing capillary pressure curves without the need to refit the experimental data. Therefore previous curve fits can be used, and the transition between the existing fit and the relationship in the adsorption region is easily calculated. The data-model comparison shows good agreement. This extension is a simple and convenient way to extend existing curves to the dry region. C1 Sandia Natl Labs, Environm Restorat Technol Dept 6131, Albuquerque, NM 87185 USA. RP Webb, SW (reprint author), Sandia Natl Labs, Environm Restorat Technol Dept 6131, POB 5800,MS 0719, Albuquerque, NM 87185 USA. NR 20 TC 57 Z9 58 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 2000 VL 36 IS 6 BP 1425 EP 1430 DI 10.1029/2000WR900057 PG 6 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 317LL UT WOS:000087226800006 ER PT J AU Birkholzer, JT Tsang, YW AF Birkholzer, JT Tsang, YW TI Modeling the thermal-hydrologic processes in a large-scale underground heater test in partially saturated fractured tuff SO WATER RESOURCES RESEARCH LA English DT Article ID DRIVEN HYDROTHERMAL FLOW; YUCCA-MOUNTAIN AB The Drift Scale Test (DST) is being conducted in an underground facility at Yucca Mountain, Nevada, to probe the coupled thermal, hydrological, mechanical, and chemical processes likely to occur in the fractured rock mass around a potential high-level nuclear waste repository. Thermal-hydrological processes in the DST have been simulated using a three-dimensional numerical model. The model incorporates the realistic test configuration and all available site-specific measurements pertaining to the thermal and hydrological properties of the unsaturated fractured tuff of the test block. The modeled predictions were compared to the extensive set of measured data collected in the first year of this 8-year-long test. The mean error between the predictions and measurement at 12 months of heating for over 1600 temperature sensors is about 2 degrees C. Heat-pipe signature in the temperature data, indicating two-phase regions of liquid-vapor counterflow: is seen in both the measurements and simulated results. The redistribution of moisture content in the rock mass (resulting from vaporization and condensation) was probed by periodic air-injection testing and geophysical measurements. Good agreement also occurred between the model predictions and these measurements. The general agreement between predictions from the numerical simulations and the measurements of the thermal test indicates that our fundamental understanding of the coupled thermal-hydrologic processes at Yucca Mountain is sound. However, effects of spatial heterogeneity from discrete fractures that are observed in the temperature data are not matched by simulations from the numerical model, which treat the densely spaced fractures as a continuum. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. RP Birkholzer, JT (reprint author), Hochtief AG, Niederlassung Dusseldorf, Zollhof 30, D-40221 Dusseldorf, Germany. RI Birkholzer, Jens/C-6783-2011 OI Birkholzer, Jens/0000-0002-7989-1912 NR 22 TC 36 Z9 36 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN PY 2000 VL 36 IS 6 BP 1431 EP 1447 DI 10.1029/2000WR900025 PG 17 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 317LL UT WOS:000087226800007 ER PT J AU Mann, JB Meek, TL Knight, ET Capitani, JF Allen, LC AF Mann, JB Meek, TL Knight, ET Capitani, JF Allen, LC TI Configuration energies of the d-block elements SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID ELECTRONEGATIVITY AB Configuration energies (CE) of the d-block elements (Croups 3-11) are electronegativities evaluated from the formula CE = (p epsilon(s) + q epsilon(d))/(p + q). epsilon(s) and epsilon(d) are the multiplet-averaged one-electron energies of the s- and d-orbitals of atoms which are in the lowest energy of the configurations s(n)d(m) and s(n-1)d(m+1), and whose highest known oxidation state is (p + q). The orbital energies an obtained from spectroscopic data. Configuration energies generally increase across a row, with the highest values occurring at nickel, silver, and gold; all are lower than the CE of silicon, the least electronegative nonmetal (except for gold which has a CE equal to that of silicon). Down the groups configuration energies invariably decrease from the first row to the second row; for Groups 7-12, the third-row element has a CE higher than that of the second-row element, due to increasing relativistic stabilization of the 6s orbitals. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ W Indies, Dept Biol & Chem Sci, Cave Hill, Barbados. Depaul Univ, Dept Chem, Chicago, IL 60604 USA. Manhattan Coll, Dept Chem, Bronx, NY 10471 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. NR 25 TC 56 Z9 57 U1 1 U2 13 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 MAY 31 PY 2000 VL 122 IS 21 BP 5132 EP 5137 DI 10.1021/ja9928677 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 323HH UT WOS:000087559700014 ER PT J AU Elder, SH Cot, FM Su, Y Heald, SM Tyryshkin, AM Bowman, MK Gao, Y Joly, AG Balmer, ML Kolwaite, AC Magrini, KA Blake, DM AF Elder, SH Cot, FM Su, Y Heald, SM Tyryshkin, AM Bowman, MK Gao, Y Joly, AG Balmer, ML Kolwaite, AC Magrini, KA Blake, DM TI The discovery and study of nanocrystalline TiO2-(MoO3) core-shell materials SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Review ID ELECTRON-PARAMAGNETIC-RESONANCE; LASER RAMAN-SPECTROSCOPY; SMALL SEMICONDUCTOR CRYSTALLITES; QUANTUM-DOT COMPOSITES; X-RAY PHOTOELECTRON; MOLYBDENUM OXIDE; COLLOIDAL TIO2; SURFACE MODIFICATION; PHYSICAL-CHEMISTRY; ALUMINA CATALYSTS AB Here we report the synthesis of a series of new nanocrystalline TiO2-(MoO3) core-shell materials whose photoabsorption energy (PE, the energy required to excite TiOz-core valence band electrons to MoO3- shell conduction band states) properties are correlated with both the nanoparticle size and the degree of chemical interaction between the TiO2 core and the MoO3 shell. The TiO2-(MoO3) nanoparticle size can be readily adjusted from 80 to 40 Angstrom, and in this series, the PE decreases from 2.88 to 2.60 eV with decreasing particle sits. The systematic PE red-shift exhibited by the core-shell materials is ascribed to the change in the relative position of the MoO3-shell conduction band as it evolves from less than a monolayer to a two monolayer shell. C1 Pacific NW Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Elder, SH (reprint author), Pacific NW Lab, William R Wiley Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Tyryshkin, Alexei/A-5219-2008; Bowman, Michael/F-4265-2011 OI Bowman, Michael/0000-0003-3464-9409 NR 107 TC 117 Z9 118 U1 12 U2 110 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 MAY 31 PY 2000 VL 122 IS 21 BP 5138 EP 5146 DI 10.1021/ja992768t PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 323HH UT WOS:000087559700015 ER PT J AU James, EW Liu, DJ Evans, JW AF James, EW Liu, DJ Evans, JW TI Relaxation effects in random sequential adsorption: application to chemisorption systems SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article DE random sequential adsorption; chemisorption; diffusion; desorption; relaxation ID DIFFUSIONAL RELAXATION; KINETICS; SURFACE; PD(100); OXYGEN; PHASE AB We consider the effect of slow relaxation processes in two models for irreversible chemisorption which incorporate superlattice ordering of the adsorbed layer on a square lattice of adsorption sites. The first model involves adsorption of monomers onto single empty sites, and we the second involves dissociative adsorption of dimers onto diagonally adjacent empty sites, where adsorption in both models occurs subject to the constraint that no adjacent pairs of occupied sites can be created. These adsorption processes produce adlayers comprised of disordered 'checkerboard' or c(2 x 2) domains, adsorption continuing until a non-equilibrium 'jammed' state is reached where no further space is available for adsorption. We focus on characterizing the evolution from this jammed state as a result of slow surface diffusion, or slow desorption (or reaction) processes. These relaxation processes open up further adsorption sites which are immediately filled in the presence of continued adsorption. In all cases, evolution involves Lifshitz-Cahn-Allen-type coarsening of the c(2 x 2) domains. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Math, Ames, IA 50011 USA. RP Evans, JW (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. NR 36 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD MAY 30 PY 2000 VL 165 IS 1-3 BP 241 EP 254 DI 10.1016/S0927-7757(99)00440-9 PG 14 WC Chemistry, Physical SC Chemistry GA 287HV UT WOS:000085501200016 ER PT J AU Bartelt, MC Hannon, JB Schmid, AK Stoldt, CR Evans, JW AF Bartelt, MC Hannon, JB Schmid, AK Stoldt, CR Evans, JW TI Island formation during deposition or etching SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Review DE models of non-equilibrium phenomena; low-energy electron microscopy; scanning tunneling microscopy; epitaxy; etching; growth; nucleation; cobalt; copper; ruthenium; silicon; oxygen; low-index single crystal surfaces ID SUBMONOLAYER EPITAXIAL-GROWTH; ENERGY-ELECTRON DIFFRACTION; RANDOM CELLULAR STRUCTURES; INTERLAYER MASS-TRANSPORT; MOLECULAR-BEAM EPITAXY; SELF-DIFFUSION; SIZE DISTRIBUTIONS; 2-CELL CORRELATIONS; SURFACE-DIFFUSION; ADATOM ISLANDS AB The behavior of a non equilibrium lattice-gas model for irreversible formation of two-dimensional islands during submonolayer deposition or etching is examined in detail. In particular, recent developments in describing capture of diffusing species by islands of various sizes are reviewed. Both exact and geometric descriptions of capture are discussed, elucidating the role of the local environment of the islands, and its dependence on island size, on adatom capture and individual island growth rates. Limitations in mean-field treatments of capture are noted. These results are applied to characterize the growth of Ag islands on Ag(100), Cu/Co islands on Ru(0001), and pits on Si(001) etched with molecular oxygen. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Sandia Natl Labs, Livermore, CA 94550 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Math, Ames, IA 50011 USA. RP Bartelt, MC (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 105 TC 17 Z9 17 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD MAY 30 PY 2000 VL 165 IS 1-3 BP 373 EP 403 DI 10.1016/S0927-7757(99)00419-7 PG 31 WC Chemistry, Physical SC Chemistry GA 287HV UT WOS:000085501200022 ER PT J AU Knupp, PM AF Knupp, PM TI Achieving finite element mesh quality via optimization of the Jacobian matrix norm and associated quantities. Part I - a framework for surface mesh optimization SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE unstructured grid generation; finite element mesh; mesh optimization; mesh smoothing ID GRID GENERATION METHOD AB Structured mesh quality optimization methods are extended to optimization of unstructured triangular, quadrilateral, and mixed finite element meshes. New interpretations of well-known nodally based objective functions are made possible using matrices and matrix norms. The matrix perspective also suggests several new objective functions. Particularly significant is the interpretation of the Oddy metric and the smoothness objective functions in terms of the condition number of the metric tensor and Jacobian matrix, respectively. Objective functions are grouped according to dimensionality to form weighted combinations. A simple unconstrained local optimum is computed using a modified Newton iteration. The optimization approach was implemented in the CUBIT mesh generation code and tested on several problems. Results were compared against several standard element-based quality measures to demonstrate that good mesh quality can be achieved with nodally based objective functions. Published in 2000 by John Wiley & Sons. C1 Sandia Natl Labs, Parallel Comp Sci Dept, Albuquerque, NM 87185 USA. RP Knupp, PM (reprint author), Sandia Natl Labs, Parallel Comp Sci Dept, M-S 0847,POB 5800, Albuquerque, NM 87185 USA. NR 26 TC 88 Z9 90 U1 1 U2 6 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD MAY 30 PY 2000 VL 48 IS 3 BP 401 EP 420 DI 10.1002/(SICI)1097-0207(20000530)48:3<401::AID-NME880>3.0.CO;2-D PG 20 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 313HH UT WOS:000086993900004 ER PT J AU Yates, MZ Birnbaum, ER McCleskey, TM AF Yates, MZ Birnbaum, ER McCleskey, TM TI Colored polymer microparticles through carbon dioxide-assisted dyeing SO LANGMUIR LA English DT Letter ID DISPERSION POLYMERIZATION; WATER; PARTICLES; SIZE; DYES AB A new procedure is described for dyeing polymer beads using liquid carbon dioxide as a plasticizer to facilitate transport; of dye into the particle phase. Aqueous latexes consisting of monodisperse polystyrene particles with surface-grafted poly(N-vinylpyrrolidone) were dyed with Sudan Red 7B using CO2 at 25 degrees C and 310 bar. Adding CO2 to the headspace above the latex resulted in some dyeing of the polymer, but better results were obtained by forming an emulsion of CO2 in the aqueous latex phase. Emulsions were formed with both a fluorinated and a hydrocarbon-based surfactant. It was found that the carbon dioxide emulsion greatly enhances the transfer of dye into the polystyrene without altering the size or morphology of the particles. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP McCleskey, TM (reprint author), Univ Calif Los Alamos Natl Lab, MS J514, Los Alamos, NM 87545 USA. RI McCleskey, Thomas/J-4772-2012; OI Mccleskey, Thomas/0000-0003-3750-3245 NR 16 TC 21 Z9 22 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 30 PY 2000 VL 16 IS 11 BP 4757 EP 4760 DI 10.1021/la000049i PG 4 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 318VG UT WOS:000087304100001 ER PT J AU Assink, RA Celina, M Dunbar, TD Alam, TM Clough, RL Gillen, KT AF Assink, RA Celina, M Dunbar, TD Alam, TM Clough, RL Gillen, KT TI Analysis of hydroperoxides in solid polyethylene by MAS C-13 NMR and EPR SO MACROMOLECULES LA English DT Article ID THERMALLY-INITIATED OXIDATION; ISOTACTIC POLYPROPYLENE; OXIDIZED POLYOLEFINS; CROSS-LINKING; FREE-RADICALS; RADIATION; ESR; PRODUCTS; SCISSION AB C-13-enriched polyethylene was subjected to gamma-irradiation in the presence of air at. 25 and 80 degrees C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 degrees C irradiated sample by C-13 magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studied by annealing the irradiated samples in air at temperatures ranging from 22 to 110 degrees C. A time-temperature superposition analysis provided an activation energy of 108 kJ/mol for the hydroperoxide decomposition process. The primary products of hydroperoxide decomposition were ketones and secondary alcohols with lesser amounts of acids and caters. EPR measurements suggest that the reactive hydroperoxide species reside in the amorphous phase of polyethylene, consistent with degradation occurring in the amorphous phase. C1 Sandia Natl Labs, Dept Organ Mat, Albuquerque, NM 87185 USA. RP Assink, RA (reprint author), Sandia Natl Labs, Dept Organ Mat, POB 5800, Albuquerque, NM 87185 USA. NR 43 TC 24 Z9 24 U1 1 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 30 PY 2000 VL 33 IS 11 BP 4023 EP 4029 DI 10.1021/ma991970d PG 7 WC Polymer Science SC Polymer Science GA 320AF UT WOS:000087378300014 ER PT J AU Karaman, I Sehitoglu, H Beaudoin, AJ Chumlyakov, YI Maier, HJ Tome, CN AF Karaman, I Sehitoglu, H Beaudoin, AJ Chumlyakov, YI Maier, HJ Tome, CN TI Modeling the deformation behavior of Hadfield steel single and polycrystals due to twinning and slip SO ACTA MATERIALIA LA English DT Article DE twinning; austenite; stress-strain relationship; constitutive equations; texture ID TEXTURE DEVELOPMENT; ZIRCONIUM ALLOYS; FCC METALS; KINETICS; SIMULATION AB Stress-strain responses of single and polycrystals of Hadfield steel were modeled using a viscoplastic self-consistent approach. A unique hardening formulation was proposed in the constitutive model incorporating length scales associated with spacing between twin lamellae and grain boundaries. TEM observations lend further support to the length scales incorporated into the constitutive model. Many of the experimental findings were made on [(1) over bar 11] and [(1) over bar 44] crystal orientations deformed in tension, displaying fine twin lamellae at small strains in addition to slip in intra-twin regions. A natural outcome of the model was the small deformation activity inside the twinned regions and higher deformations between the twins. The model utilized dislocation density as a state variable and predicted the stress-strain responses and texture evolution in single crystals accurately over a broad range of strains. The responses of polycrystals with three grain sizes (100, 300, and 1000 mu m) were also captured closely with the model in addition to the twin volume fraction evolution with increasing deformation. Based on the simulations, it was possible to explain unequivocally the upward curvature in stress-strain curves in the single crystals and in coarse grained polycrystals of Hadfield steel. Overall, the combined experimental and modeling efforts provide a reliable tool to characterize slip-twin interaction in low stacking fault energy f.c.c. materials. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. Siberian Phys Tech Inst, Tomsk 634050, Russia. Univ Gesamthsch Paderborn, Lerhstuhl Werkstoffkunde, D-33095 Paderborn, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Sehitoglu, H (reprint author), Univ Illinois, Dept Mech & Ind Engn, 1206 W Green St, Urbana, IL 61801 USA. RI Karaman, Ibrahim/E-7450-2010; yuriy, chumlyakov/C-6033-2009; Tome, Carlos/D-5058-2013; Chumlyakov, Yuriy/R-6496-2016 OI Karaman, Ibrahim/0000-0001-6461-4958; NR 36 TC 144 Z9 145 U1 7 U2 40 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 29 PY 2000 VL 48 IS 9 BP 2031 EP 2047 DI 10.1016/S1359-6454(00)00051-3 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 352AP UT WOS:000089192600001 ER PT J AU Kumar, M King, WE Schwartz, AJ AF Kumar, M King, WE Schwartz, AJ TI Modifications to the microstructural topology in f.c.c. materials through thermomechanical processing SO ACTA MATERIALIA LA English DT Article DE annealing; grain boundaries; grain boundary network; scanning electron microscopy; electron diffraction ID BOUNDARY-CHARACTER-DISTRIBUTION; ORIENTATION IMAGING MICROSCOPY; HIGH-PURITY NICKEL; GRAIN-BOUNDARY; POLYCRYSTALLINE MATERIALS; TRIPLE JUNCTION; INTERGRANULAR CORROSION; CSL DISTRIBUTIONS; STAINLESS-STEEL; ANNEALING TWINS AB Recently, there has been increased attention toward determination of the grain boundary character distribution (GBCD) and manipulation of the relative fractions of "special" and "random" boundaries in the microstructure through thermomechanical processing techniques in order to improve materials properties like corrosion, creep resistance, and weldability. Most of the "optimization" treatments reported in the literature have been performed on f.c.c. metals and alloys with medium to low stacking fault energies, and have resulted in microstructures with high fractions of Sigma 3, Sigma 9, and Sigma 27 boundaries, or Sigma 3(n) boundaries. Experiments to modify the GBCD of oxygen-free electronic Cu and Inconel 600 through sequential thermomechanical processing are presented and the efficacy of these processing routes is assessed in terms of microstructural descriptors like the random grain boundary network and the distribution of triple junctions. This analysis has shown that Sigma 3(n) reactions, which occur as a consequence of multiple twinning, not only improve the GBCD but are also critical for disrupting the connectivity of the random boundary network. Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Kumar, M (reprint author), Univ Calif Lawrence Livermore Natl Lab, 7000 East Ave, Livermore, CA 94550 USA. NR 52 TC 158 Z9 162 U1 4 U2 34 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 29 PY 2000 VL 48 IS 9 BP 2081 EP 2091 DI 10.1016/S1359-6454(00)00045-8 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 352AP UT WOS:000089192600005 ER PT J AU Wang, Y Srolovitz, DJ Rickman, JM Lesar, R AF Wang, Y Srolovitz, DJ Rickman, JM Lesar, R TI Dislocation motion in the presence of diffusing solutes: A computer simulation study SO ACTA MATERIALIA LA English DT Article DE dislocation mobility; diffusion; defects; Portevin-LeChatelier effects ID ATMOSPHERE AB A discrete lattice, kinetic Monte Carlo model is developed to simulate the motion of an edge dislocation in the presence of interacting, diffusing solute atoms that have a misfit with respect to the matrix. The simulation self-consistently determines the solute concentration profile tin two spatial dimensions), as well as the associated dislocation velocity. The solute segregation profile around the moving dislocation is characterized at low velocity by a condensed solute cloud near and on one side of the dislocation core, a region depleted of solute on the opposite side and a diffuse solute (Cottrell) atmosphere further from the core. At high velocity, no condensed solute cloud forms. The relation between the dislocation velocity and the applied stress shows a low-velocity, solute drag branch and a high-velocity branch, typified by no solute cloud but with occasional solute trapping. At intermediate velocities, the dislocation stochastically jumps between these two branches. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. Princeton Univ, Dept Mech & Aerosp Engn, Princeton, NJ 08544 USA. Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 USA. Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Srolovitz, DJ (reprint author), Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. RI LeSar, Richard/G-1609-2012 NR 20 TC 44 Z9 45 U1 1 U2 22 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 29 PY 2000 VL 48 IS 9 BP 2163 EP 2175 DI 10.1016/S1359-6454(00)00035-5 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 352AP UT WOS:000089192600013 ER PT J AU Zhu, JH Liu, CT AF Zhu, JH Liu, CT TI Defect structures in ZrCo2 Laves phase SO ACTA MATERIALIA LA English DT Article DE intermetallic compound; casting; X-ray diffraction; lattice defects; mechanical properties (fracture & fracture toughness) ID INTERMETALLIC COMPOUNDS; POINT-DEFECTS; ENTHALPIES; ALLOYS AB Point defect structures in the C15 ZrCo2 alloys were studied by bulk density and X-ray lattice parameter measurements. It was found that, for the ZrCo2 alloys quenched from 1000 degrees C, the lattice parameter increases linearly as the Zr content increases up to 33.3 at.% Zr. The lattice parameter of the Laves phase remains constant for the alloys with Zr content higher than 33.3 at.%, indicating that the solubility range of Zr in ZrCo2 on the Zr-rich side is essentially zero. The constitutional defects were found to be of the anti-site type. Thermal vacancies exhibiting a maximum at the stoichiometric composition were observed in the ZrCo2 Laves phase alloys after quenching from 1250 and 1000 degrees C, with higher thermal vacancies obtained from 1250 degrees C. The defect structures in the ZrCo2 phase may be correlated to the relative magnitude of formation enthalpies for anti-site and quadruple defects in this compound. Thermal vacancy concentration at a level of 1% in ZrCo2 does not affect fracture toughness at room temperature. Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. RP Zhu, JH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008,Bldg 4500S-MS6115, Oak Ridge, TN 37831 USA. OI Liu, Chain Tsuan/0000-0001-7888-9725 NR 19 TC 20 Z9 23 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 29 PY 2000 VL 48 IS 9 BP 2339 EP 2347 DI 10.1016/S1359-6454(00)00014-8 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 352AP UT WOS:000089192600028 ER PT J AU Shih, CJ Meyers, MA Nesterenko, VF Chen, SJ AF Shih, CJ Meyers, MA Nesterenko, VF Chen, SJ TI Damage evolution in dynamic deformation of silicon carbide SO ACTA MATERIALIA LA English DT Article DE carbides; mechanical properties; dynamic phenomena; transmission electron microscopy (TEM) ID COMPRESSIVE STRESS STATES; STRAIN-RATE; BRITTLE SOLIDS; FRACTURE-TOUGHNESS; CERAMIC MATERIALS; STACKING-FAULTS; FAILURE; DEPENDENCE; MECHANISMS; BEHAVIOR AB Damage evolution was investigated in silicon carbide by subjecting it to dynamic deformation in (a) a compression Hopkinson-Kolsky bar (compressive stresses of 5 GPa), and (b) high-velocity impact under confinement (compressive stresses of 19-32 GPa) by a cylindrical (rod) tungsten alloy projectile. Considerable evidence of plastic deformation, as dislocations and stacking faults, was found in the fractured specimens. A polytype transformation was observed through a significant increase in the 6H-SiC phase at compressive stresses higher than 4.5 GPa (in the vicinity of the dynamic compressive failure strength). Profuse dislocation activity was evident in the frontal layer in the specimen recovered from the projectile impact. The formation of this frontal layer is proposed to be related to the high lateral confinement, imposed by the surrounding material. It is shown that plastic deformation is consistent with an analysis based on a ductility parameter (Delta = K-C/tau(y)root pi c). The microstructural defects and their evolution were found to be dependent on the concentration of boron and aluminum, which were added as sintering aids. Several mechanisms are considered for the initiation of fracture: (a) dilatant cracks induced by mismatch in the effective elastic moduli between two adjacent grains, leading to internal tensile stresses and creating transgranular fracture. Finite element calculations show that high tensile stresses are generated due to elastic compatibility strains. (b) Zener-Stroh cracks nucleated by the piled up dislocations along grain boundaries, and resulting in intergranular fracture; (c) cracks due to existing flaws connected with grain-boundary phases, voids, etc.; and (d) stress concentrations due to twinning and stacking faults. The high dislocation density observed in the impacted specimen is consistent with existing models of microplasticity. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif San Diego, Dept Mech & Aerosp Engn, La Jolla, CA 92093 USA. Lawrence Berkeley Natl Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. RP Meyers, MA (reprint author), Univ Calif San Diego, Dept Mech & Aerosp Engn, La Jolla, CA 92093 USA. RI Meyers, Marc/A-2970-2016 OI Meyers, Marc/0000-0003-1698-5396 NR 76 TC 64 Z9 68 U1 10 U2 55 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 29 PY 2000 VL 48 IS 9 BP 2399 EP 2420 DI 10.1016/S1359-6454(99)00409-7 PG 22 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 352AP UT WOS:000089192600033 ER PT J AU Scofield, JH Borland, N Fleetwood, DM AF Scofield, JH Borland, N Fleetwood, DM TI Temperature-independent switching rates for a random telegraph signal in a silicon metal-oxide-semiconductor field-effect transistor at low temperatures SO APPLIED PHYSICS LETTERS LA English DT Article ID 1/F NOISE; DEVICES; KINETICS; DEFECTS; CAPTURE; STATES; TRAPS AB We have observed discrete random telegraph signals (RTSs) in the drain voltages of three, nominally 1.25 mu mx1.25 mu m, enhancement-mode p-channel metal-oxide-semiconductor transistors operated in strong inversion in their linear regimes with constant drain-current and gate-voltage bias, for temperatures ranging from 4.2 to 300 K. The switching rates for all RTSs observed above 30 K were thermally activated. The switching rate for the only RTS observed below 30 K was thermally activated above 30 K but temperature independent below 10 K. This response is consistent with a crossover from thermal activation to tunneling at low temperatures. Implications are discussed for models of change exchange between the Si and the near-interfacial SiO2. (C) 2000 American Institute of Physics. [S0003-6951(00)01822-2]. C1 Oberlin Coll, Dept Phys, Oberlin, OH 44074 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Scofield, JH (reprint author), Oberlin Coll, Dept Phys, Oberlin, OH 44074 USA. NR 19 TC 23 Z9 23 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 29 PY 2000 VL 76 IS 22 BP 3248 EP 3250 AR PII [S0003-6951(00)01822-2] DI 10.1063/1.126596 PG 3 WC Physics, Applied SC Physics GA 317QX UT WOS:000087239400030 ER PT J AU Shan, W Walukiewicz, W Yu, KM Wu, J Ager, JW Haller, EE Xin, HP Tu, CW AF Shan, W Walukiewicz, W Yu, KM Wu, J Ager, JW Haller, EE Xin, HP Tu, CW TI Nature of the fundamental band gap in GaNxP1-x alloys SO APPLIED PHYSICS LETTERS LA English DT Article ID GAP1-XNX ALLOYS; DEPENDENCE; PRESSURE; ENERGY AB The optical properties of GaNxP1-x alloys (0.007 less than or equal to x less than or equal to 0.031) grown by gas-source molecular-beam epitaxy have been studied. An absorption edge appears in GaNxP1-x at energy below the indirect Gamma(V)-X-C transition in GaP, and the absorption edge shifts to lower energy with increasing N concentration. Strong photomodulation signals associated with the absorption edges in GaNxP1-x indicate that a direct fundamental optical transition is taking place, revealing that the fundamental band gap has changed from indirect to direct. This N-induced transformation from indirect to direct band gap is explained in terms of an interaction between the highly localized nitrogen states and the extended states at the Gamma conduction-band minimum. (C) 2000 American Institute of Physics. [S0003-6951(00)01922-7]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RP Shan, W (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Wu, Junqiao/G-7840-2011; Yu, Kin Man/J-1399-2012; OI Wu, Junqiao/0000-0002-1498-0148; Yu, Kin Man/0000-0003-1350-9642; Ager, Joel/0000-0001-9334-9751 NR 17 TC 179 Z9 179 U1 2 U2 13 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 29 PY 2000 VL 76 IS 22 BP 3251 EP 3253 AR PII [S0003-6951(00)01922-7] DI 10.1063/1.126597 PG 3 WC Physics, Applied SC Physics GA 317QX UT WOS:000087239400031 ER PT J AU Bennett, JA Holland, OW Budde, M Thomas, DK Feldman, LC AF Bennett, JA Holland, OW Budde, M Thomas, DK Feldman, LC TI Complete surface exfoliation of 4H-SiC by H+- and Si+-coimplantation SO APPLIED PHYSICS LETTERS LA English DT Article ID SILICON-CARBIDE; SMART-CUT(R) PROCESS; ION-IMPLANTATION; LAYER TRANSFER; HYDROGEN; TEMPERATURE AB Implantation of 4H-SiC with H-1(+) and Si-28(+) ions followed by annealing is shown to result in complete ejection or exfoliation of the implanted layer. This is in contrast to H+-only implantation where only partial exfoliation of the surface can be achieved. The mechanisms of this process and its dependence on implantation conditions are discussed. It is shown that amorphization of the surface region during Si+ irradiation is a necessary condition to produce this effect, and that it depends critically upon the thickness of the amorphous layer. Stress, induced by bulk recrystallization of the amorphized layer, acts as an additional driving force for H+ induced exfoliation causing the surface layer to separate completely at a depth near the end-of-range of the H+ ions. The morphologies of the newly exposed surfaces are studied by profilometry measurements and atomic force microscopy. (C) 2000 American Institute of Physics. [S0003- 6951(00)03722-0]. C1 Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37835 USA. RP Bennett, JA (reprint author), Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. NR 11 TC 3 Z9 3 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 29 PY 2000 VL 76 IS 22 BP 3265 EP 3267 DI 10.1063/1.126640 PG 3 WC Physics, Applied SC Physics GA 317QX UT WOS:000087239400036 ER PT J AU Nivorozhkin, AL Segal, BM Musgrave, KB Kates, SA Hedman, B Hodgson, KO Holm, RH AF Nivorozhkin, AL Segal, BM Musgrave, KB Kates, SA Hedman, B Hodgson, KO Holm, RH TI Metallocyclopeptide complexes with M-II(S center dot Cys)(4) chromophores SO INORGANIC CHEMISTRY LA English DT Article ID X-RAY-ABSORPTION; METAL-BINDING SITES; CRYSTAL-STRUCTURE; THIOLATE CHEMISTRY; REDOX PROPERTIES; IRON COMPLEXES; PROTEIN; HYDROGENASE; PEPTIDES; RUBREDOXIN AB The tetracysteinyl peptide cyclo[Lys(1,12)](Gln-Cys-Gly-Val-Cys-Gly-Lys-Cys-Ile-Ala-Cys-Lys)(subset of L(Cys . SH)(4)) was synthesized by solid-phase methods using an Fmoc/t-Bu/allyl strategy on a PAL-PEG-PS support. The formation of the 1:1 complexes with M = Fe2+, Co2+, and Ni2+ was observed by spectrophotomeric monitoring of reactions in aqueous solution at pH 7.5. Size exclusion chromatography indicated that the peptide is a monomer and the complexes are dimers [M-2(subset of L(Cys . S)(4))(2)] in aqueous buffer at pH 7.5. Cobalt and nickel K-edge X-ray absorption data and EXAFS analysis of [Co-2(subset of L(Cy . S)(4))(2)] and [Ni-2(subset of L(Cys . S)(4))(2)] as lyophilized solids rue reported. Derived bond distances are Co-S = 2.30 Angstrom and Ni-S = 2.21 Angstrom. From the collective results provided by absorption spectra, K-edges, EXAFS, and bond length comparisons with known structures, it is shown that [Fe-2(subset of L(Cys . S)(4))(2)] and [Co-2(subset of L(Cys . S)(4))(2)] possess distorted tetrahedral structures and [Ni-2(subset of L(Cys . S)(4))(2)] has distorted square planar stereochemistry. The Co(TT) chromophore is particularly distinctive of the assigned structure, displaying three components of the parent tetrahedral ligand field transition (4)A(2) --> T-4(1)(P) (610, 685, 740 nm). The observed structures conform to the intrinsic stereochemical preferences of the metal ions. Structures for the binuclear complexes are suggested. These are the first characterized metal complexes of a cysteinyl cyclopeptide and among the few well-documented complexes of synthetic cyclopeptides. This study is a desirable first step in the design of cyclic peptides for the binding of mononuclear and polynuclear metal centers. C1 Stanford Univ, Dept Chem, Stanford, CA 94305 USA. SLAC, Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA. PE Biosyst, Framingham, MA 01701 USA. RP Hedman, B (reprint author), Stanford Univ, Dept Chem, Stanford, CA 94305 USA. FU NCRR NIH HHS [RR-01209]; NIGMS NIH HHS [GM 28856] NR 60 TC 30 Z9 30 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 29 PY 2000 VL 39 IS 11 BP 2306 EP 2313 DI 10.1021/ic990421l PG 8 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 320DN UT WOS:000087386600012 PM 12526490 ER PT J AU Luo, J Reddy, KB Salameh, AS Wishart, JF Isied, SS AF Luo, J Reddy, KB Salameh, AS Wishart, JF Isied, SS TI Ruthenium bisbipyridine complexes of horse heart cytochrome c: Characterization and comparative intramolecular electron-transfer rates determined by pulse radiolysis and flash photolysis SO INORGANIC CHEMISTRY LA English DT Article ID DRIVING-FORCE; DERIVATIVES; OXIDATION; CHEMISTRY AB The reaction of [Ru(bpy)(2)L(H2O)](2+) (bpy = 2,2'-bipyridine, L = imidazole, water) with reduced horse heart cytochrome c results in coordination of [Ru-II(bpy)(2)L] at the His 33 and His 26 sites. Coordination at the His 33 site gave a diastereomeric [Ru-II(bpy)(2)L]-His-cyt c(II) mixture favoring the Il-Ru form regardless of the substituent on the bipyridine ligands, while substitution at the more buried His 26 site gave an isomeric distribution that varies according to the substituent on the bipyridine ligands. The diastereomeric aquoproteins (L = H2O) are distinguished by their redox potentials and their conversion to the corresponding fluorescent imidazole proteins. Intramolecular electron transfer between the reduced ruthenium bipyridine and cyt c(III) in [Ru-II(bpy(.))(bpy)L]-His33-cyt c(II) was determined by reductive pulse radiolysis using the aqueous electron as a reducing agent, k(ret) = (2.0 +/- 0.3) x 10(5) s(-1), and k(ret) is independent of the sixth ligand L = H2O imidazole. In addition, the rate constant for intramolecular electron transfer from cyt c(II) to the ruthenium(III) center in [Ru-III(bpy)(2)L]-His33-cyt c(II)) was determined by oxidative pulse radiolysis using azide and carbonate radicals. This rate is very sensitive to the nature of the sixth ligand. When L = H2O, the intramolecular electron-transfer rate for the major diastereomer Lambda-cis-[Ru-III (bpy)(2)(H2O)]-His33-cyt c(II) is k = 1.1 x 10(4) s(-1) and is independent of pH between 5.6 and 8.3. The minor Delta-cis-[Ru-III(bpy)(2)(H2O)]-His33-cyt c(II) isomer has pH-dependent electrochemistry and a lower rate of intramolecular electron transfer. Complete conversion from L = H2O to L = imidazole is slow, requiring more than 7 days in 1 M imidazole. A lower limit (k > 2 x 10(6) s(-1)) for the intramolecular electron-transfer rate constant in [Ru-III(bpy)(2)(L)]-His33-cyt c(II), L = imidazole, could be obtained by pulse radiolysis in the absence of the slower reacting aquo species. This observation is in agreement with the value of 3 x 10(6) s(-1) measured by flash photolysis. Earlier pulse radiolysis experiments primarily measured the aquoligated ruthenium protein, while the flash photolysis experiments measured the imidazole-ligated fraction because it is the only species oxidatively quenched in the photoinduced reactions. Intramolecular electron-transfer reactions for a new series of ruthenium bipyridine complexes, [Ru(dabpy)(2)L]-His33-cyt c proteins (dabpy = 4,4'-diamino-2,2'-bipyridine ) (L imidazole, pyridine, isonicotinamide and pyrazine), proceed with lower driving force, resulting in slower rate constants amenable to measurement by oxidative pulse radiolysis. The electron-transfer rate constants for this series spanned a wide range of the Marcus log k vs Delta G plot. C1 Rutgers State Univ, Dept Chem, Piscataway, NJ 08854 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Isied, SS (reprint author), Rutgers State Univ, Dept Chem, Piscataway, NJ 08854 USA. RI Wishart, James/L-6303-2013 OI Wishart, James/0000-0002-0488-7636 NR 23 TC 14 Z9 14 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 29 PY 2000 VL 39 IS 11 BP 2321 EP 2329 DI 10.1021/ic9913381 PG 9 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 320DN UT WOS:000087386600014 PM 12526492 ER PT J AU Marshall, SL AF Marshall, SL TI A periodic Green function for calculation of coloumbic lattice potentials SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID POISSON EQUATION; MADELUNG CONSTANTS; MOLECULAR-POLARIZATION; ADSORBED MONOLAYERS; BOUNDARY-CONDITIONS; LAPLACES-EQUATION; FOURIER-SERIES; SUMS; SYSTEMS; SUMMATION AB The modified Green function appropriate for solution of interior boundary Value problems of Laplace's equation in a three-dimensional rectangular parallelepiped, subject to periodic boundary conditions, is developed. This allows the determination of the potential due to an arbitrary continuous charge distribution and its periodic replications in three dimensions. Summation of the eigenfunction expansion by application of the Poisson-Jacobi formula gives a Ewald sum, while application of the Poisson summation formula results in a two-dimensional potential that is perturbed by a rapidly converging Fourier cosine series involving K-0 Bessel functions. The latter constitutes a generalization of formulae described by Lekner. Numerical results show that the K-0 expansion is more rapidly convergent than the Ewald sum, and could therefore substantially reduce the computational effort involved in the molecular simulation of ionic and polar fluids. The Green function is also shown to be related to the asymptotic behaviour of lattice sums for the screened Coulomb potential, in the limit as the screening constant tends to zero. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Marshall, SL (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. RI Marshall, Simon/E-9518-2010 NR 57 TC 22 Z9 22 U1 0 U2 10 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD MAY 29 PY 2000 VL 12 IS 21 BP 4575 EP 4601 DI 10.1088/0953-8984/12/21/304 PG 27 WC Physics, Condensed Matter SC Physics GA 327HK UT WOS:000087788300007 ER PT J AU McQueeney, RJ Bishop, AR Yi, YS Yu, ZG AF McQueeney, RJ Bishop, AR Yi, YS Yu, ZG TI Charge localization and phonon spectra in hole-doped La2NiO4 SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter ID HUBBARD-MODEL; NEUTRON-SCATTERING; DOPING STATES; STRIPE-PHASE; HARTREE-FOCK; SUPERCONDUCTORS; MAGNETISM; SPINS; ORDER; ANTIFERROMAGNETS AB The in-plane oxygen vibrations in La2NiO4 are investigated for several hole-doping concentrations both theoretically and experimentally via inelastic neutron scattering. Using an inhomogeneous Hartree-Fock plus random-phase approximation numerical method in a two-dimensional Peierls-Hubbard model, it is found that the doping induces stripe ordering of localized charges, and that the strong electron-lattice coupling causes the in-plane oxygen modes to split into two subbands. This result agrees with the phonon band splitting observed by inelastic neutron scattering in La2-xSrxNiO4. Predictions of strong electron-lattice coupling in La2NiO4, the proximity of both oxygen-centred and nickel-centred charge ordering, and the relation between charged stripe ordering and the splitting of the in-plane phonon band upon doping are emphasized. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP McQueeney, RJ (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RI Yu, Z/B-5547-2009; McQueeney, Robert/A-2864-2016 OI McQueeney, Robert/0000-0003-0718-5602 NR 36 TC 11 Z9 12 U1 1 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 EI 1361-648X J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD MAY 29 PY 2000 VL 12 IS 21 BP L317 EP L322 DI 10.1088/0953-8984/12/21/102 PG 6 WC Physics, Condensed Matter SC Physics GA 327HK UT WOS:000087788300002 ER PT J AU Hollowood, TJ Khoze, VV AF Hollowood, TJ Khoze, VV TI ADHM and D-instantons in orbifold AdS/CFT duality SO NUCLEAR PHYSICS B LA English DT Article DE solitons; monopoles; instantons; 1/N expansion; duality; gauge field theories; supersymmetry and duality ID SUPERSYMMETRIC GAUGE-THEORY; CONFORMAL FIELD-THEORIES; MULTIINSTANTON CALCULUS; STRING THEORY; BRANES; N=4 AB We consider ADHM instantons in product group gauge theories that arise from D3-branes located at points in the orbifold R-6/Z(P.) At finite N we argue that the ADHM construction and collective coordinate integration measure can be deduced from the dynamics of D-instantons in the D3-brane background. For the large-N conformal field theories of this type, we compute a saddle-point approximation of the ADHM integration measure and show that it is proportional to the partition function of D-instantons in the dual AdS(5) x S(5/)Z(P) background, in agreement with the orbifold AdS/CFT correspondence. Matching the expected behaviour of D-instantous, we find that when S-5/Z(P) is smooth a saddle-point solution only exists in the sector where the instanton charges in each gauge group faster are the same. However, when S-3/Z(P) is singular, the instanton charges at large N need not be the same and the space of saddle-point solutions has a number of distinct branches which represent the possible fractionations of D-instantans at the singularity. For the theories with a type 0B dual the saddle-point solutions manifest two types of D-instantons. (C) 2000 Elsevier Science B.V, All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret T8, Los Alamos, NM 87545 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. Univ Wales, Dept Phys, Swansea SA2 8PP, W Glam, Wales. RP Hollowood, TJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret T8, POB 1663, Los Alamos, NM 87545 USA. OI Khoze, Valentin V/0000-0003-3006-4147 NR 32 TC 7 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 29 PY 2000 VL 575 IS 1-2 BP 78 EP 106 DI 10.1016/S0550-3213(00)00086-9 PG 29 WC Physics, Particles & Fields SC Physics GA 322TV UT WOS:000087525700004 ER PT J AU Alaimo, PJ Arndtsen, BA Bergman, RG AF Alaimo, PJ Arndtsen, BA Bergman, RG TI Alkylation of iridium via tandem carbon-hydrogen bond activation/decarbonylation of aldehydes. Access to complexes with tertiary and highly hindered metal-carbon bonds SO ORGANOMETALLICS LA English DT Review ID C-H ACTIVATION; ADDITION REDUCTIVE ELIMINATION; ASSISTED OXIDATIVE ADDITION; RAY CRYSTAL-STRUCTURE; TRANSITION-METAL; MIGRATORY INSERTION; FORMYL COMPLEXES; INTERMOLECULAR HYDROACYLATION; BINDING SELECTIVITIES; MEDIATED ACTIVATION AB Reactions between Cp*(PMe3)Ir(Me)OTf (1) and aldehydes (RCHO) proceed with high selectivity to give the hydrocarbyl carbonyl salts [Cp*(PMe3)Ir(R)(CO)][OTf] (R = Me (2), Et (3), n-Pr (4), c-Pr (5), Ph (6), 1-ethylpropyl(7), p-tolyl(8), mesityl(9), 2-(Z)-1-phenylpropenyl (10), vinyl(13), t-Bu (14), 1-adamantyl(17)). This tandem C-H bond activation/decarbonylation reaction provides access to the first isolated tertiary alkyl complexes of iridium. X-ray diffraction studies were performed on mesityl complex 9, tert-butyl derivative 15, and 1-adamantyl compound 18. Decarbonylation of cyclopropyl complex 5 results in irreversible opening of the cyclopropyl ring. This reaction has provided useful information concerning the mechanism of C-H activation of cyclopropane by 1. Hydride reduction of the p-tolyl carbonyl salt 8 has provided an example of a rare transition-metal formyl complex, Cp*-(PMe3)Ir(p-tolyl)(CHO) (28). C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. RP Bergman, RG (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 150 TC 64 Z9 64 U1 2 U2 27 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0276-7333 J9 ORGANOMETALLICS JI Organometallics PD MAY 29 PY 2000 VL 19 IS 11 BP 2130 EP 2143 DI 10.1021/om9910064 PG 14 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 318PE UT WOS:000087292200012 ER PT J AU Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Korte, CM Kutschke, R Lange, DJ Morrison, RJ Nelson, HN Qiao, C Ryd, A Tajima, H Witherell, MS Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Katayama, N Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z AF Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Gronberg, J Hill, TS Korte, CM Kutschke, R Lange, DJ Morrison, RJ Nelson, HN Qiao, C Ryd, A Tajima, H Witherell, MS Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Katayama, N Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Ng, CR Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kravchenko, I Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z CA Cleo Collaboration TI Search for D-0-(0) mixing SO PHYSICAL REVIEW LETTERS LA English DT Article ID CABIBBO-SUPPRESSED DECAYS; LUND MONTE-CARLO; CP VIOLATION; JET FRAGMENTATION; E+E-PHYSICS; DETECTOR; LIFETIMES; D-0 AB We have studied the "wrong-sign" process D-0 --> K+ pi(-) to search for D-0-(D) over bar(0) mixing. The data come from 9.0 fb(-1) of e(+) e(-) collisions at root s approximate to 10 GeV recorded with the CLEO II.V detector. We measure the relative rate of the wrong-sign process D-0 --> K+ pi(-) to the Cabibbo-favored process (D) over bar(0) --> K+ pi(-) to be R = (0.3321(-0.065)(+0.063) +/- 0.040)%. We study D-0 --> K+ pi(-) as a function of decay time to distinguish direct doubly Cabibbo-suppressed decay from D-0-(D) over bar(0) mixing. The amplitudes that describe D-0-(D) over bar(0) mixing, x ' and y ', are consistent with zero. At the 95% C.L. and without assumptions concerning charge-parity (CP) violating parameters, we find (1/2)x(/2) < 0.041% and -5.8% < y ' < 1.0%. C1 Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K15 5B6, Canada. McGill Univ, Montreal, PQ H3A 2T, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. RP Godang, R (reprint author), Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 28 TC 115 Z9 115 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5038 EP 5042 DI 10.1103/PhysRevLett.84.5038 PG 5 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300003 ER PT J AU Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Borras, K Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Cihangir, S Ciobanu, CI Clark, AG Connolly, A Convery, M Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, C Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Melese, P Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, C Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, F Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, S AF Affolder, T Akimoto, H Akopian, A Albrow, MG Amaral, P Amendolia, SR Amidei, D Anikeev, K Antos, J Apollinari, G Arisawa, T Asakawa, T Ashmanskas, W Atac, M Azfar, F Azzi-Bacchetta, P Bacchetta, N Bailey, MW Bailey, S de Barbaro, P Barbaro-Galtieri, A Barnes, VE Barnett, BA Barone, M Bauer, G Bedeschi, F Belforte, S Bellettini, G Bellinger, J Benjamin, D Bensinger, J Beretvas, A Berge, JP Berryhill, J Bevensee, B Bhatti, A Binkley, M Bisello, D Blair, RE Blocker, C Bloom, K Blumenfeld, B Blusk, SR Bocci, A Bodek, A Bokhari, W Bolla, G Bonushkin, Y Borras, K Bortoletto, D Boudreau, J Brandl, A van den Brink, S Bromberg, C Brozovic, M Bruner, N Buckley-Geer, E Budagov, J Budd, HS Burkett, K Busetto, G Byon-Wagner, A Byrum, KL Campbell, M Carithers, W Carlson, J Carlsmith, D Cassada, J Castro, A Cauz, D Cerri, A Chan, AW Chang, PS Chang, PT Chapman, J Chen, C Chen, YC Cheng, MT Chertok, M Chiarelli, G Chirikov-Zorin, I Chlachidze, G Chlebana, F Christofek, L Chu, ML Cihangir, S Ciobanu, CI Clark, AG Connolly, A Convery, M Conway, J Cooper, J Cordelli, M Cranshaw, J Cronin-Hennessy, D Cropp, R Culbertson, R Dagenhart, D DeJongh, F Dell'Agnello, S Dell'Orso, M Demina, R Demortier, L Deninno, M Derwent, PF Devlin, T Dittmann, JR Donati, S Done, J Dorigo, T Eddy, N Einsweiler, K Elias, JE Engels, E Erdmann, W Errede, D Errede, S Fan, Q Feild, RG Ferretti, C Field, RD Fiori, I Flaugher, B Foster, GW Franklin, M Freeman, J Friedman, J Fukui, Y Galeotti, S Gallinaro, M Gao, T Garcia-Sciveres, M Garfinkel, AF Gatti, P Gay, C Geer, S Gerdes, DW Giannetti, P Glagolev, V Gold, M Goldstein, J Gordon, A Goshaw, AT Gotra, Y Goulianos, K Green, C Groer, L Grosso-Pilcher, C Guenther, M Guillian, G da Costa, JG Guo, RS Haber, C Hafen, E Hahn, SR Hall, C Handa, T Handler, R Hao, W Happacher, F Hara, K Hardman, AD Harris, RM Hartmann, F Hatakeyama, K Hauser, J Heinrich, J Heiss, A Herndon, M Hinrichsen, B Hoffman, KD Holck, C Hollebeek, R Holloway, L Hughes, R Huston, J Huth, J Ikeda, H Incandela, J Introzzi, C Iwai, J Iwata, Y James, E Jensen, H Jones, M Joshi, U Kambara, H Kamon, T Kaneko, T Karr, K Kasha, H Kato, Y Keaffaber, TA Kelley, K Kelly, M Kennedy, RD Kephart, R Khazins, D Kikuchi, T Kirk, M Kim, BJ Kim, HS Kim, MJ Kim, SH Kim, YK Kirsch, L Klimenko, S Koehn, P Kongeter, A Kondo, K Konigsberg, J Kordas, K Korn, A Korytov, A Kovacs, E Kroll, J Kruse, M Kuhlmann, SE Kurino, K Kuwabara, T Laasanen, AT Lai, N Lami, S Lammel, S Lamoureux, JI Lancaster, M Latino, G LeCompte, T Lee, AM Leone, S Lewis, JD Lindgren, M Liss, TM Liu, JB Liu, YC Lockyer, N Loken, J Loreti, M Lucchesi, D Lukens, P Lusin, S Lyons, L Lys, J Madrak, R Maeshima, K Maksimovic, P Malferrari, L Mangano, M Mariotti, M Martignon, G Martin, A Matthews, JAJ Mayer, J Mazzanti, P McFarland, KS McIntyre, P McKigney, E Melese, P Menguzzato, M Menzione, A Mesropian, C Miao, T Miller, R Miller, JS Minato, H Miscetti, S Mishina, M Mitselmakher, G Moggi, N Moore, C Moore, E Moore, R Morita, Y Mukherjee, A Muller, T Munar, A Murat, P Murgia, S Musy, M Nachtman, J Nahn, S Nakada, H Nakaya, T Nakano, I Nelson, C Neuberger, D Newman-Holmes, C Ngan, CYP Nicolaidi, F Niu, H Nodulman, L Nomerotski, A Oh, SH Ohmoto, T Ohsugi, T Oishi, R Okusawa, T Olsen, J Pagliarone, C Palmonari, F Paoletti, R Papadimitriou, V Pappas, SP Partos, D Patrick, J Pauletta, G Paulini, M Paus, C Pescara, L Phillips, TJ Piacentino, G Pitts, KT Plunkett, R Pompos, A Pondrom, L Pope, G Popovic, M Prokoshin, F Proudfoot, J Ptohos, F Punzi, G Ragan, K Rakitine, A Reher, D Reichold, A Riegler, W Ribon, A Rimondi, F Ristori, L Robertson, WJ Robinson, A Rodrigo, T Rolli, S Rosenson, L Roser, R Rossin, R Sakumoto, WK Saltzberg, D Sansoni, A Santi, L Sato, H Savard, P Schlabach, P Schmidt, EE Schmidt, MP Schmitt, M Scodellaro, L Scott, A Scribano, A Segler, S Seidel, S Seiya, Y Semenov, A Semeria, F Shah, T Shapiro, MD Shepard, PF Shibayama, T Shimojima, M Shochet, M Siegrist, J Signorelli, G Sill, A Sinervo, P Singh, P Slaughter, AJ Sliwa, K Smith, C Snider, FD Solodsky, A Spalding, J Speer, T Sphicas, P Spinella, F Spiropulu, M Spiegel, L Steele, J Stefanini, A Strologas, J Strumia, F Stuart, D Sumorok, K Suzuki, T Takano, T Takashima, R Takikawa, K Tamburello, P Tanaka, M Tannenbaum, B Taylor, W Tecchio, M Teng, PK Terashi, K Tether, S Theriot, D Thurman-Keup, R Tipton, P Tkaczyk, S Tollefson, K Tollestrup, A Toyoda, H Trischuk, W de Troconiz, JF Tseng, J Turini, N Ukegawa, F Vaiciulis, T Valls, J Vejcik, S Velev, G Vidal, R Vilar, R Volobouev, I Vucinic, D Wagner, RG Wagner, RL Wahl, J Wallace, NB Walsh, AM Wang, C Wang, CH Wang, MJ Watanabe, T Waters, D Watts, T Webb, R Wenzel, H Wester, WC Wicklund, AB Wicklund, E Williams, HH Wilson, P Winer, BL Winn, D Wolbers, S Wolinski, D Wolinski, J Wolinski, S Worm, S Wu, X Wyss, J Yagil, A Yao, W Yeh, GP Yeh, P Yoh, J Yosef, C Yoshida, T Yu, I Yu, S Zanetti, A Zetti, F Zucchelli, S CA CDF Collaboration TI Diffractive dijets with a leading antiproton in (p)over-bar-p collisions at root s=1800 GeV SO PHYSICAL REVIEW LETTERS LA English DT Article ID FERMILAB TEVATRON; POMERON; HERA AB We report results from a study of events with a leading antiproton of beam momentum fraction 0.905 < x(F) < 0.965 and 4-momentum transfer squared \t\ < 3 GeV2 produced in (p) over bar p collisions at root s = 1800 GeV at the Fermilab Tevatron collider. Approximately 2% of the events contain two jets of transverse energy E-T(jet) > 7 GeV. Using the dijet events, we evaluate the diffractive structure function of the antiproton and compare it with expectations based on results obtained in diffractive deep inelastic scattering experiments at the DESY cp collider HERA. C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Acad Sinica, Inst Phys, Taipei 11529, Taiwan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Bologna, Ist Nazl Fis Nucl, I-40127 Bologna, Italy. Brandeis Univ, Waltham, MA 02254 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. Univ Cantabria, Inst Fis Cantabria, E-39005 Santander, Spain. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Joint Nucl Res Inst, RU-141980 Dubna, Russia. Duke Univ, Durham, NC 27708 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Florida, Gainesville, FL 32611 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Geneva, CH-1211 Geneva 4, Switzerland. Harvard Univ, Cambridge, MA 02138 USA. Hiroshima Univ, Higashihiroshima 724, Japan. Univ Illinois, Urbana, IL 61801 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76128 Karlsruhe, Germany. Kyungpook Natl Univ, Korean Hadron Collider Lab, Taegu 702701, South Korea. Seoul Natl Univ, Seoul 151742, South Korea. Sungkyunkwan Univ, Suwon 440746, South Korea. High Energy Accelerator Res Org, KEK, Tsukuba, Ibaraki 305, Japan. MIT, Cambridge, MA 02139 USA. McGill Univ, Inst Particle Phys, Montreal, PQ H3A 2T8, Canada. Univ Toronto, Toronto, ON M5S 1A7, Canada. Univ Michigan, Ann Arbor, MI 48109 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Ohio State Univ, Columbus, OH 43210 USA. Osaka City Univ, Osaka 588, Japan. Univ Oxford, Oxford OX1 3RH, England. Univ Padua, Ist Nazl Fis Nucl, Sez Padova, I-35131 Padua, Italy. Univ Penn, Philadelphia, PA 19104 USA. Univ Pisa, Ist Nazl Fis Nucl, I-56100 Pisa, Italy. Scuola Normale Super Pisa, I-56100 Pisa, Italy. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Rockefeller Univ, New York, NY 10021 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Texas A&M Univ, College Stn, TX 77843 USA. Texas Tech Univ, Lubbock, TX 79409 USA. Univ Trieste, Ist Nazl Fis Nucl, Udine, Italy. Univ Tsukuba, Tsukuba, Ibaraki 305, Japan. Tufts Univ, Medford, MA 02155 USA. Waseda Univ, Tokyo 169, Japan. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06520 USA. RP Affolder, T (reprint author), Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Nomerotski, Andrei/A-5169-2010; Azzi, Patrizia/H-5404-2012; Lancaster, Mark/C-1693-2008; Vucinic, Dejan/C-2406-2008; Punzi, Giovanni/J-4947-2012; Chiarelli, Giorgio/E-8953-2012; Scodellaro, Luca/K-9091-2014; Paulini, Manfred/N-7794-2014; Prokoshin, Fedor/E-2795-2012 OI Azzi, Patrizia/0000-0002-3129-828X; Punzi, Giovanni/0000-0002-8346-9052; Chiarelli, Giorgio/0000-0001-9851-4816; Scodellaro, Luca/0000-0002-4974-8330; Paulini, Manfred/0000-0002-6714-5787; Prokoshin, Fedor/0000-0001-6389-5399 NR 22 TC 160 Z9 160 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5043 EP 5048 DI 10.1103/PhysRevLett.84.5043 PG 6 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300004 ER PT J AU Abbott, D Ahmidouch, A Anklin, H Arvieux, J Ball, J Beedoe, S Beise, EJ Bimbot, L Boeglin, W Breuer, H Brindza, P Carlini, R Chant, NS Danagoulian, S Dow, K Ducret, JE Dunne, J Ewell, L Eyraud, L Furget, C Garcon, M Gilman, R Glashausser, C Gueye, P Gustafsson, K Hafidi, K Honegger, A Jourdan, J Kox, S Kumbartzki, G Lu, L Lung, A Mack, D Markowitz, P McIntyre, J Meekins, D Merchez, F Mitchell, J Mohring, R Mtingwa, S Mrktchyan, H Pitz, D Qin, L Ransome, RD Real, JS Roos, PG Rutt, P Sawafta, R Stepanyan, S Tieulent, R Tomasi-Gustafsson, E Turchinetz, W Vansyoc, K Volmer, J Voutier, E Vulcan, W Williamson, C Wood, SA Yan, C Zhao, J Zhao, W AF Abbott, D Ahmidouch, A Anklin, H Arvieux, J Ball, J Beedoe, S Beise, EJ Bimbot, L Boeglin, W Breuer, H Brindza, P Carlini, R Chant, NS Danagoulian, S Dow, K Ducret, JE Dunne, J Ewell, L Eyraud, L Furget, C Garcon, M Gilman, R Glashausser, C Gueye, P Gustafsson, K Hafidi, K Honegger, A Jourdan, J Kox, S Kumbartzki, G Lu, L Lung, A Mack, D Markowitz, P McIntyre, J Meekins, D Merchez, F Mitchell, J Mohring, R Mtingwa, S Mrktchyan, H Pitz, D Qin, L Ransome, RD Real, JS Roos, PG Rutt, P Sawafta, R Stepanyan, S Tieulent, R Tomasi-Gustafsson, E Turchinetz, W Vansyoc, K Volmer, J Voutier, E Vulcan, W Williamson, C Wood, SA Yan, C Zhao, J Zhao, W TI Measurement of tensor polarization in elastic electron-deuteron scattering at large momentum transfer SO PHYSICAL REVIEW LETTERS LA English DT Article ID STRUCTURE-FUNCTION A(Q(2)); ANALYZING POWERS; FORM-FACTORS; TARGET AB Tensor polarization observables (t(20), t(21), and t(22)) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c)(2). The experiment was performed at the Jefferson Laboratory in Hall C using the electron High Momentum Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q(2) the deuteron charge form factors G(C) and G(Q). They are in good agreement with relativistic calculations and disagree with perturbative QCD predictions. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Univ Grenoble 1, Inst Sci Nucl, IN2P3, F-38026 Grenoble, France. CEA Saclay, SPhN, DAPNIA, F-91191 Gif Sur Yvette, France. Univ Maryland, College Pk, MD 20742 USA. MIT, Nucl Sci Lab, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Bates Linear Accelerator, Middleton, MA USA. Rutgers State Univ, Piscataway, NJ 08855 USA. Basel Inst Phys, Basel, Switzerland. LNS Saclay, F-91191 Gif Sur Yvette, France. N Carolina Agr & Technol State Univ, Greensboro, NC 27411 USA. Florida Int Univ, Miami, FL 33199 USA. IPNO, IN2P3, F-91406 Orsay, France. Yerevan Phys Inst, Yerevan 375036, Armenia. RP Abbott, D (reprint author), Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. RI McIntyre, Justin/P-1346-2014; Lu, Lanchun/E-3551-2011 OI McIntyre, Justin/0000-0002-3706-4310; NR 26 TC 111 Z9 113 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5053 EP 5057 DI 10.1103/PhysRevLett.84.5053 PG 5 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300006 ER PT J AU Joosten, R Powell, J Guo, FQ Haustein, PE Larimer, RM McMahan, MA Norman, EB O'Neil, JP Rowe, MW VanBrocklin, HF Wutte, D Xu, XJ Cerny, J AF Joosten, R Powell, J Guo, FQ Haustein, PE Larimer, RM McMahan, MA Norman, EB O'Neil, JP Rowe, MW VanBrocklin, HF Wutte, D Xu, XJ Cerny, J TI Measurement of excitation functions in the reactions (197)Au((11)C, xn)(208-x)At using a radioactive (11)C beam SO PHYSICAL REVIEW LETTERS LA English DT Article ID ION AB A light-element radioactive ion-beam capability has been developed at the LBNL 88-Inch Cyclotron. The system is based on the coupled-cyclotrons method and utilizes short-lived species, e.g., (11)C, (14)O, (13)N produced by (p, II) and (p, alpha) reactions at the LBNL Biomedical Isotope Facility Cyclotron. In a first experiment, (197)Au((11)C, xn)(208-x) At excitation functions have been measured for energies ranging from the Coulomb barrier up to 110 MeV using a beam of (11)C with intensities up to (1-2) x 10(8) ions/sec on target. The results of this experiment are compared to measurements of (197)Au((12)C, xn)(209-x) At excitation functions. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Joosten, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Nucl Sci, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 13 TC 10 Z9 10 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5066 EP 5069 DI 10.1103/PhysRevLett.84.5066 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300009 ER PT J AU Raptis, CA Pratt, ST AF Raptis, CA Pratt, ST TI Vibrational autoionization in Rydberg states of ammonia SO PHYSICAL REVIEW LETTERS LA English DT Article ID RESONANCE SPECTROSCOPY; POLYATOMIC-MOLECULES; IONIZATION; PHOTOIONIZATION; SELECTION; DYNAMICS; SERIES; BANDS; NH3+; H-3 AB Rotationally resolved photoelectron spectroscopy is used to elucidate the mechanism for vibrational autoionization via the nontotally symmetric umbrella vibration of ammonia (NH3). This mechanism depends strongly on the character of the autoionizing level, and the data demonstrate that both the electronic and rotational degrees of freedom can compensate for the change in vibrational symmetry that occurs for odd changes in the quantum number of the umbrella vibration. This result has implications for models of the mode dependence of vibrational autoionization in polyatomic molecules. C1 Argonne Natl Lab, Argonne, IL 60439 USA. RP Pratt, ST (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 24 TC 2 Z9 2 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5078 EP 5081 DI 10.1103/PhysRevLett.84.5078 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300012 ER PT J AU Mineev-Weinstein, M Wiegmann, PB Zabrodin, A AF Mineev-Weinstein, M Wiegmann, PB Zabrodin, A TI Integrable structure of interface dynamics SO PHYSICAL REVIEW LETTERS LA English DT Article ID 2-DIMENSIONAL STRING THEORY; DIFFUSION-LIMITED AGGREGATION; 2-MATRIX MODEL; ISING-MODEL; HIERARCHY; SYMMETRIES; EQUATIONS; SURFACE; FLOWS AB We establish the equivalence of 2D contour dynamics to the dispersionless limit of the integrable Toda hierarchy constrained by a string equation. Remarkably, the same hierarchy underlies 2D quantum gravity. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. LD Landau Theoret Phys Inst, Moscow, Russia. Joint Inst Chem Phys, Moscow 117334, Russia. ITEP, Moscow 117259, Russia. RP Mineev-Weinstein, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS-B213, Los Alamos, NM 87545 USA. NR 30 TC 145 Z9 148 U1 2 U2 15 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 MAY 29 PY 2000 VL 84 IS 22 BP 5106 EP 5109 DI 10.1103/PhysRevLett.84.5106 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300019 ER PT J AU White, JM Muller, SJ AF White, JM Muller, SJ TI Viscous heating and the stability of Newtonian and viscoelastic Taylor-Couette flows SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELASTIC INSTABILITIES; TEMPERATURE-GRADIENT; ROTATING CYLINDERS AB The effects of viscous heating on the stability of Taylor-Couette flow were investigated through flow visualization experiments for Newtonian and viscoelastic fluids. For highly viscous Newtonian fluids, viscous heating drives a transition to a new, oscillatory mode of instability at a critical Reynolds number significantly below that at which the inertial transition is observed in isothermal flows. The effects of viscous heating may explain the discrepancies between the observed and predicted critical conditions and the symmetry of the disturbance flow for viscoelastic instabilities. C1 Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP White, JM (reprint author), Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. NR 17 TC 40 Z9 41 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 MAY 29 PY 2000 VL 84 IS 22 BP 5130 EP 5133 DI 10.1103/PhysRevLett.84.5130 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300025 ER PT J AU Varnum, WS Delamater, ND Evans, SC Gobby, PL Moore, JE Wallace, JM Watt, RG Colvin, JD Turner, R Glebov, V Soures, J Stoeckl, C AF Varnum, WS Delamater, ND Evans, SC Gobby, PL Moore, JE Wallace, JM Watt, RG Colvin, JD Turner, R Glebov, V Soures, J Stoeckl, C TI Progress toward ignition with noncryogenic double-shell capsules SO PHYSICAL REVIEW LETTERS LA English DT Article ID INERTIAL CONFINEMENT FUSION; TETRAHEDRAL HOHLRAUMS; FACILITY AB Inertial confinement fusion implosions using capsules with two concentric shells separated by a low density region (double shells) are reported which closely follow one dimensional (1D) radiatively driven hydrodynamics simulations. Capsule designs which mitigate An M-band radiation asymmetries appear to correspond more closely to 1D simulations than targets lacking mitigation of hohlraum drive M-band nonuniformities. One capsule design achieves over 50% of the unperturbed 1D calculated yield at a convergence ratio of 25.5, comparable to that of a double-shell design for an ignition capsule at the National Ignition Facility. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Rochester, Laser Energet Lab, Rochester, NY 14623 USA. RP Varnum, WS (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 24 Z9 25 U1 1 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5153 EP 5155 DI 10.1103/PhysRevLett.84.5153 PG 3 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300031 ER PT J AU Kunchur, MN Ivlev, BI Christen, DK Phillips, JM AF Kunchur, MN Ivlev, BI Christen, DK Phillips, JM TI Metallic normal state of Y1Ba2Cu3O7-delta SO PHYSICAL REVIEW LETTERS LA English DT Article ID UPPER CRITICAL-FIELD; FLUX-FLOW; SUPERCONDUCTING LA2-XSRXCUO4; THIN-FILMS; YBA2CU3O7-DELTA; LAALO3(100); TRANSITION; BEHAVIOR; CORE AB Flux flow was studied over an entire temperature range down to T similar to 2% of T-c by using intense pulsed current densities to overcome flux-vortex pinning. The resistivity at high vortex velocities is proportional to B and roughly follows rho similar to rho(n)B/H-c2, with a prefactor of order unity. Contrary to some speculation, rho(n) saturates to a finite residual value as T --> 0, indicating a metallic (rho --> finite) rather than insulating (rho --> infinity) normal state, and the vortex dissipation continues to be conventional as T --> 0. C1 Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. Univ Autonoma San Luis Potosi, Inst Fis, San Luis Potosi, Mexico. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Kunchur, MN (reprint author), Univ S Carolina, Dept Phys & Astron, Columbia, SC 29208 USA. NR 23 TC 35 Z9 35 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 29 PY 2000 VL 84 IS 22 BP 5204 EP 5207 DI 10.1103/PhysRevLett.84.5204 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300044 ER PT J AU Gehring, PM Park, SE Shirane, G AF Gehring, PM Park, SE Shirane, G TI Soft phonon anomalies in the relaxer ferroelectric Pb(Zn1/3Nb2/3)(0.92)Ti0.08O3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-SCATTERING; PHASE-TRANSITIONS; SINGLE-CRYSTALS; PEROVSKITE ALLOYS; LEAD MAGNONIOBATE; PBMG1/3NB2/3O3; BEHAVIOR AB Neutron inelastic scattering measurements of the polar transverse optic phonon mode dispersion in the cubic relaxor Pb(Zn1/3Nb2/3)(0.92)Ti0.08O3 at 500 K reveal anomalous behavior in which the optic branch appears to drop precipitously into the acoustic branch at a finite value of the momentum transfer q = 0.2 Angstrom(-1) measured from the zone center. We speculate that this behavior is the result of nanometer-sized polar regions in the crystal. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Penn State Univ, Mat Res Lab, University Pk, PA 16802 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Gehring, PM (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. OI Gehring, Peter/0000-0002-9236-2046 NR 20 TC 120 Z9 121 U1 0 U2 15 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 MAY 29 PY 2000 VL 84 IS 22 BP 5216 EP 5219 DI 10.1103/PhysRevLett.84.5216 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300047 ER PT J AU Davidson, RC Qin, H AF Davidson, RC Qin, H TI Effects of axial momentum spread on the electron-ion two-stream instability in high-intensity ion beams SO PHYSICS LETTERS A LA English DT Article ID CHARGED-PARTICLE BEAMS; STABILITY THEOREM; STORAGE-RINGS; PSR AB Use is made of the Vlasov-Maxwell equations to describe the electron-ion two-stream instability driven by the directed axial motion of a high-intensity ion beam propagating through a stationary population of (unwanted) background electrons. The ion beam is treated as continuous in the z-direction, and the electrons are electrostatically confined in the transverse direction by the space-charge potential produced by the excess ion charge. The analysis is carried out for arbitrary beam intensity, consistent with transverse confinement of the beam particles, and arbitrary fractional charge neutralization by the background electrons. For the case of overlapping step-function ion and electron density profiles, corresponding to monoenergetic electrons and ions in the transverse direction, detailed stability properties are calculated, including the important effects of an axial momentum spread, over a wide range of system parameters for dipole perturbations with azimuthal mode number l=1. The two-stream instability growth rate is found to increase with increasing beam intensity, increasing fractional charge neutralization, and decreasing proximity of the conducting wall. It is shown that Landau damping associated with a modest axial momentum spread of the beam ions and background electrons has a strong stabilizing influence on the instability. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Princeton Univ, Plasma Phys Lab, Princeton, NJ 08543 USA. RP Davidson, RC (reprint author), Princeton Univ, Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. NR 24 TC 14 Z9 14 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 MAY 29 PY 2000 VL 270 IS 3-4 BP 177 EP 185 DI 10.1016/S0375-9601(00)00296-6 PG 9 WC Physics, Multidisciplinary SC Physics GA 322BY UT WOS:000087491400011 ER PT J AU Serron, SA Aldridge, WS Danell, RM Meyer, TJ AF Serron, SA Aldridge, WS Danell, RM Meyer, TJ TI Synthesis of derivatized amino acids for the study of electron transfer SO TETRAHEDRON LETTERS LA English DT Article DE amino acids and derivatives; electron donor; electron transfer; chromophores; ruthenium complexes ID OXIDATION; OXORUTHENIUM(IV) AB The synthesis of a new electron transfer donor and two new ruthenium chromophores are described based on coupling to derivatized proline residues for the purpose of constructing molecular assemblies capable of undergoing photoinduced electron transfer. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. RP Meyer, TJ (reprint author), Univ Calif Los Alamos Natl Lab, MS A127, Los Alamos, NM 87545 USA. NR 15 TC 8 Z9 8 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0040-4039 J9 TETRAHEDRON LETT JI Tetrahedron Lett. PD MAY 29 PY 2000 VL 41 IS 21 BP 4039 EP 4042 DI 10.1016/S0040-4039(00)00584-0 PG 4 WC Chemistry, Organic SC Chemistry GA 321KQ UT WOS:000087455000009 ER PT J AU Guo, XZ Mathews, DF Mikaelian, G Khakoo, MA Crowe, A Kanik, I Trajmar, S Zeman, V Bartschat, K Fontes, CJ AF Guo, XZ Mathews, DF Mikaelian, G Khakoo, MA Crowe, A Kanik, I Trajmar, S Zeman, V Bartschat, K Fontes, CJ TI Differential cross sections for electron-impact excitation of krypton at low incident energies: I. Excitation of the 4p(5)5s configuration SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID HEAVY NOBLE-GASES; SPIN-POLARIZED ELECTRONS; NEAR-THRESHOLD; ORIENTATION PARAMETERS; RESONANCE RADIATION; R-MATRIX; SCATTERING; STATES; KR; XE AB The electron-impact excitation of the individual levels that constitute the 4p(5)5s configuration of Kr is experimentally and theoretically investigated at incident electron energies of 20.0, 15.0, 13.5 and 12.0 eV, for scattering angles ranging from 10 degrees to 135 degrees. High resolution electron energy-loss spectroscopy is used to obtain spectral intensities for the excitation of each of the four 4p55s levels from the ground state. The intensities lead to three differential cross section ratios. Absolute electron-impact excitation cross sections are then determined by normalization to elastic scattering cross sections using the conventional inelastic to elastic normalization method. The present theoretical cross sections are calculated using two different methods, namely the R-matrix method and the unitarized first-order many-body theory. Comparisons between the experimental and the theoretical results show some good agreement, but reveal areas where significant improvement of the present models is needed. Additionally, it is shown that in the present case, just as in general for the rare gases, differential cross section ratios provide a sensitive test of theoretical models as well as unique insights concerning relativistic effects in the scattering process. Comparisons with existing models and other experimental data are also presented. C1 Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. Univ Newcastle Upon Tyne, Dept Phys, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Drake Univ, Dept Phys & Astron, Des Moines, IA 50311 USA. Univ Calif Los Alamos Natl Lab, Div Appl Theoret & Compua, Los Alamos, NM USA. RP Guo, XZ (reprint author), Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. RI Bartschat, Klaus/I-2527-2012 NR 52 TC 22 Z9 22 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 2000 VL 33 IS 10 BP 1895 EP 1919 DI 10.1088/0953-4075/33/10/306 PG 25 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 327HP UT WOS:000087788700007 ER PT J AU Guo, XZ Mathews, DF Mikaelian, G Khakoo, MA Crowe, A Kanik, I Trajmar, S Zeman, V Bartschat, K Fontes, CJ AF Guo, XZ Mathews, DF Mikaelian, G Khakoo, MA Crowe, A Kanik, I Trajmar, S Zeman, V Bartschat, K Fontes, CJ TI Differential cross sections for electron-impact excitation of krypton at low incident energies: II. Excitation of the 4p(5)5p, 4p(5)4d and 4p(5)6s configurations SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID AR; KR; XE AB This paper is the second part of two back-to-back papers concerning electron-impact excitation of Kr. This part concerns excitation of the individual levels that constitute the 4p(5)5p, 4p(5)4d and 4p(5)6s configurations of Kr, at incident electron energies (E-0) of 20.0 and 15.0 eV, for scattering angles (theta) ranging from 10 degrees to 130 degrees. As in part I, excitation cross sections are measured and calculated using the R-matrix (RM) and the unitarized first-order many-body theory (UFOMBT) methods. Comparisons between the present experimental and theoretical results, and also with other experimental results, are presented. C1 Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. Univ Newcastle Upon Tyne, Dept Phys, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Drake Univ, Dept Phys & Astron, Des Moines, IA 50311 USA. Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. RP Guo, XZ (reprint author), Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. RI Bartschat, Klaus/I-2527-2012 NR 9 TC 6 Z9 6 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 2000 VL 33 IS 10 BP 1921 EP 1933 DI 10.1088/0953-4075/33/10/307 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 327HP UT WOS:000087788700008 ER PT J AU Spivey, JJ Gangwal, SK Zoeller, JR Winslow, JC Srivastava, RD AF Spivey, JJ Gangwal, SK Zoeller, JR Winslow, JC Srivastava, RD TI Syngas conversion to fuels and chemicals - Preface SO CATALYSIS TODAY LA English DT Editorial Material C1 Res Triangle Inst, Ctr Proc Res, Res Triangle Pk, NC 27709 USA. Eastman Chem Co, Kingsport, TN 37662 USA. US DOE, Natl Energy Technol Lab, Pittsburgh, PA 15236 USA. Sci Applicat Int Corp, Pittsburgh, PA 15236 USA. RP Spivey, JJ (reprint author), Res Triangle Inst, Ctr Proc Res, POB 12194, Res Triangle Pk, NC 27709 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5861 J9 CATAL TODAY JI Catal. Today PD MAY 26 PY 2000 VL 58 IS 4 BP 231 EP 231 DI 10.1016/S0920-5861(00)00255-8 PG 1 WC Chemistry, Applied; Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 319BZ UT WOS:000087321000001 ER PT J AU Li, J Ding, WL Fritz, JS AF Li, J Ding, WL Fritz, JS TI Separation of anions by ion chromatography-capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE ion chromatography-capillary electrophoresis; capillary electrophoresis-ion chromatography; background electrolyte composition; inorganic anions; organic acids; poly(diallyldimethylammonium chloride) ID EXCHANGE ELECTROKINETIC CHROMATOGRAPHY; INORGANIC ANIONS; ZONE ELECTROPHORESIS; MIGRATION BEHAVIOR; LIQUID-CHROMATOGRAPHY; CATIONIC POLYMERS; SELECTIVITY; SULFATE; WATER; OPTIMIZATION AB Capillary electrophoresis (CE) with a water-soluble ion-exchange polymer in the background electrolyte is very efficient for the separation of organic and inorganic anions because the ion-exchange selectivity, as well as differences in electrophoretic mobility, can be used for separating sample ions. Poly(diallyldimethylammonium chloride) (PDDAC) was employed for this purpose. A very stable electroosmotic flow was obtained between pH 2.3 and 8.5 due to the strong adsorption of PDDAC onto the capillary wall. The effect of ion exchange on the migration of sample anions and their separation was controlled by varying the concentration of PDDAC, the concentration and the type of salt used in the CE background electrolyte. Addition of organic solvent (e.g., acetonitrile) could also modify the sample migration and the separation. Baseline separations were obtained for anions with very similar mobilities, such as bromide and iodide, naphthalenesulfonates, and bi- and tricarboxylic acids. Typical separation efficiencies were between 195 000 and 429 000 theoretical plates per meter. Ten replicate separations gave an average RSD of 1.0% for migration times of the sample anions studied. Excellent separations were obtained for a variety of samples, including a separation of 17 inorganic and organic anions in less than 6 min. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, US Dept Energy, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Fritz, JS (reprint author), Iowa State Univ Sci & Technol, Ames Lab, US Dept Energy, Ames, IA 50011 USA. NR 32 TC 34 Z9 34 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 26 PY 2000 VL 879 IS 2 BP 245 EP 257 DI 10.1016/S0021-9673(00)00296-X PG 13 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 320CR UT WOS:000087384200014 PM 10893040 ER PT J AU Coldren, CW Larson, MC Spruytte, SG Harris, JS AF Coldren, CW Larson, MC Spruytte, SG Harris, JS TI 1200nm GaAs-based vertical cavity lasers employing GaInNAs multiquantum well active regions SO ELECTRONICS LETTERS LA English DT Article ID OPERATION AB Elemental source molecular beam epitaxy has been used to grow vertical cavity laser diodes on GaAs substrates that employ GaInNAs multiquantum well active regions and AlAs/GaAs distributed Bragg reflectors. The laser diodes emitted light at 1200nm and had threshold current densities of 2.5kA/cm(2) and efficiencies of 0.066W/A under room temperature pulsed operation. C1 Stanford Univ, Solid State & Photon Lab, Stanford, CA 94305 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Coldren, CW (reprint author), Stanford Univ, Solid State & Photon Lab, CIS 126X,Via Ortega, Stanford, CA 94305 USA. NR 3 TC 78 Z9 80 U1 0 U2 2 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD MAY 25 PY 2000 VL 36 IS 11 BP 951 EP 952 DI 10.1049/el:20000365 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 320TJ UT WOS:000087416200015 ER PT J AU Larsen, G Lotero, E Marquez, M AF Larsen, G Lotero, E Marquez, M TI Amine dendrimers as templates for amorphous silicas SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SIZE DISTRIBUTION; ADSORPTION; SURFACE AB The generation 4.0 PAMAM dendrimer is used as a template for silica gels made from tetraethyl orthosilicate via the sol-gel method. X-ray diffraction and adsorption data show that quasi-spherical dendritic structures can be used as porogens, Used as templates, amine dendrimers are unique in that (I) they have the potential, depending upon dendrimer size, to produce mesopores and micropores with single molecules instead of micelles, and (II) spheroidal pores are the expected pore shape imprinted on inorganic solids. C1 Univ Nebraska, Dept Chem Engn, Lincoln, NE 68588 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, CST, DO, Los Alamos, NM 87545 USA. Kraft Gen Foods Inc, Res & Dev, Nanotechnol Lab NanoteK, Glenview, IL 60025 USA. RP Larsen, G (reprint author), Univ Nebraska, Dept Chem Engn, Lincoln, NE 68588 USA. NR 15 TC 43 Z9 44 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 25 PY 2000 VL 104 IS 20 BP 4840 EP 4843 DI 10.1021/jp000301v PG 4 WC Chemistry, Physical SC Chemistry GA 317GW UT WOS:000087218500004 ER PT J AU Li, M Hebenstreit, W Diebold, U Tyryshkin, AM Bowman, MK Dunham, GG Henderson, MA AF Li, M Hebenstreit, W Diebold, U Tyryshkin, AM Bowman, MK Dunham, GG Henderson, MA TI The influence of the bulk reduction state on the surface structure and morphology of rutile TiO2(110) single crystals SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; INTRINSIC DEFECTS; SELF-DIFFUSION; OXYGEN; GROWTH; STM; VISUALIZATION; SPECTROSCOPY; OXIDES; PHASE AB We have investigated the relationship between different types and amounts of bulk defects and the surface morphology of TiO2(110) single crystals prepared by annealing in ultrahigh vacuum rind in oxygen. Rutile TiO2(110) specimens were cut from the same crystal and were heated in a furnace to different temperatures which resulted in different states of reduction (colors of the crystals). After characterization of the bulk defects with electron paramagnetic resonance (EPR), the specimens were studied with scanning tunneling microscopy (STM), low-energy He+ ion scattering (LETS), and work Function measurements. EPR reveals that darker rutile crystals exhibit higher concentrations of extended Ti3+ related bulk defects such as crystallographic shear planes (CSP), with a decrease in substitutional and interstitial defects as compared to lighter crystals. Surface structures with (1 x 2) features are preferably formed upon UHV annealing on these darker crystals. LEIS measurements show that all of the crystals' (110) surfaces are reoxidized upon annealing in O-18(2) (573 K, 1 x 10(-6) mbar, 10 min) and that the O-18 surface content is proportional to the bulk reduction state. UV-visible adsorption spectra and resistivity measurements also scale with the reduction states of crystals. Only the (1 x 1) structure is observed on the surface of slightly reduced crystals. Annealing in oxygen induces additional metastable structures, i.e., TiO2 clusters on blue crystals and rosette networks on dark blue crystals. C1 Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Tulane Univ, Dept Phys, New Orleans, LA 70118 USA. EM diebold@mailhost.tcs.tulane.edu RI Tyryshkin, Alexei/A-5219-2008; Diebold, Ulrike/A-3681-2010; Bowman, Michael/F-4265-2011 OI Diebold, Ulrike/0000-0003-0319-5256; Bowman, Michael/0000-0003-3464-9409 NR 45 TC 135 Z9 135 U1 5 U2 74 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 25 PY 2000 VL 104 IS 20 BP 4944 EP 4950 DI 10.1021/jp9943272 PG 7 WC Chemistry, Physical SC Chemistry GA 317GW UT WOS:000087218500018 ER PT J AU Press, WH AF Press, WH TI The runaway Universe: The race to find the future of the cosmos SO NATURE LA English DT Book Review C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Press, WH (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 25 PY 2000 VL 405 IS 6785 BP 395 EP 396 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 317DX UT WOS:000087212000019 ER PT J AU Vidale, JE Dodge, DA Earle, PS AF Vidale, JE Dodge, DA Earle, PS TI Slow differential rotation of the Earth's inner core indicated by temporal changes in scattering SO NATURE LA English DT Article ID MODEL AB The finding that the Earth's inner core might be rotating faster than the mantle(1) has important implications for our understanding of core processes, including the generation of the Earth's magnetic field(2,3). But the reported signal is subtle-a change of about 0.01 s per year in the separation of two seismic waves with differing paths through the core. Subsequent studies of such data have generally supported the conclusion that differential rotation exists(4-6), but the difficulty of accurately locating historic earthquakes(7) and possible biases induced by strong lateral variations in structure near the core-mantle boundary(8) have raised doubt regarding the proposed inner-core motion(9). Also, a study of free oscillations(10) constrained the motion to be relatively small compared to previous estimates and it has been proposed that the interaction of inner-core boundary topography and mantle heterogeneity might lock the inner core to the mantle(11). The recent detection of seismic waves scattered in the inner core(12) suggests a simple test of inner-core motion. Here we compare scattered waves recorded in Montana, USA, from two closely located nuclear tests at Novaya Zemlya, USSR, in 1971 and 1974. The data show small but coherent changes in scattering which point toward an inner-core differential rotation rate of 0.15 degrees per year-consistent with constraints imposed by the free-oscillation data(10). C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Lawrence Livermore Natl Lab, Div Geophys, Livermore, CA 94550 USA. RP Vidale, JE (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. RI Vidale, John/H-4965-2011 OI Vidale, John/0000-0002-3658-818X NR 20 TC 63 Z9 64 U1 1 U2 6 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 25 PY 2000 VL 405 IS 6785 BP 445 EP 448 DI 10.1038/35013039 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 317DX UT WOS:000087212000045 ER PT J AU Knorr, A Koch, SW Chow, WW AF Knorr, A Koch, SW Chow, WW TI Optics in the multipole approximation: from atomic systems to solids SO OPTICS COMMUNICATIONS LA English DT Article AB Starting from the microscopic light-matter interaction in form of the minimal coupling Hamiltonian, the multipole approximation for the optical response of localized electrons in atomic systems is extended to delocalized electrons in solids. A spatial averaging procedure is used to derive the electromagnetic sources for macroscopic Maxwell's equations as well as the corresponding many particle Hamiltonian on a coarse grained length scale. The results are illustrated for semiconductor bulk material up to quadrupole moments for the interband transitions, where gauge invariant equations of motion for the optical response are obtained. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Marburg, Dept Phys, D-35032 Marburg, Germany. Univ Marburg, Ctr Mat Sci, D-35032 Marburg, Germany. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Knorr, A (reprint author), Univ Marburg, Dept Phys, Renthof 5, D-35032 Marburg, Germany. NR 17 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD MAY 25 PY 2000 VL 179 IS 1-6 BP 167 EP 178 DI 10.1016/S0030-4018(00)00527-7 PG 12 WC Optics SC Optics GA 326NP UT WOS:000087741900020 ER PT J AU Johnson, MA Townes, CH AF Johnson, MA Townes, CH TI Quantum effects and optimization of heterodyne detection SO OPTICS COMMUNICATIONS LA English DT Article AB We review the classical and the quantum aspects of the noise behaviour of heterodyne detection, making connections among quantum noise in heterodyne receivers, the uncertainty principle, and the concept of electromagnetic zero-point fluctuations as a description of that noise. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Johnson, MA (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 3 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD MAY 25 PY 2000 VL 179 IS 1-6 BP 183 EP 187 DI 10.1016/S0030-4018(99)00740-3 PG 5 WC Optics SC Optics GA 326NP UT WOS:000087741900022 ER PT J AU Nieto, MM Truax, DR AF Nieto, MM Truax, DR TI Higher-power coherent and squeezed states SO OPTICS COMMUNICATIONS LA English DT Article ID EVEN; ATOM AB A closed form expression for the higher-power coherent states (eigenstates of a(j)) is given. The cases j = 3,4 are discussed in detail, including The time-evolution of the probability densities, These are compared to the case j = 2, the even-and odd-coherent states. We give the extensions to the "effective" displacement-operator, higher-power squeezed states and to the ladder-operator/minimum-uncertainty, higher-power squeezed states. The properties of all these states are discussed. Published by Elsevier Science B.V. C1 Univ Calif Los Alamos Natl Lab, Div Theoret MS B285, Los Alamos, NM 87545 USA. Univ Ulm, Abt Quantenphys, D-89069 Ulm, Germany. Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada. RP Nieto, MM (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret MS B285, Los Alamos, NM 87545 USA. NR 28 TC 13 Z9 13 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD MAY 25 PY 2000 VL 179 IS 1-6 BP 197 EP 213 DI 10.1016/S0030-4018(99)00483-6 PG 17 WC Optics SC Optics GA 326NP UT WOS:000087741900024 ER PT J AU Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Paganis, S Sampson, S Schmidke, WB Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Piotrzkowski, K Przybycien, MB Stopa, P Zawiejski, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Dannheim, D Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Benen, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH Lee, SB Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, L de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Boogert, S Cooper-Sarkar, AM Devenish, RCE Grobe-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, P Stanco, L Stroili, R Voci, C Adamczyk, L Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Catterall, C Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S AF Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Paganis, S Sampson, S Schmidke, WB Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Piotrzkowski, K Przybycien, MB Stopa, P Zawiejski, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Dannheim, D Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Benen, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH Lee, SB Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, L de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Boogert, S Cooper-Sarkar, AM Devenish, RCE Grobe-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, P Stanco, L Stroili, R Voci, C Adamczyk, L Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Catterall, C Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S CA ZEUS Collaboration TI Measurement of azimuthal asymmetries in deep inelastic scattering SO PHYSICS LETTERS B LA English DT Article ID LEPTON-PROTON SCATTERING; MONTE-CARLO GENERATOR; CROSS-SECTIONS; QCD; HERA; LEPTOPRODUCTION; DISTRIBUTIONS; ENERGIES AB The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron-proton scattering with the ZEUS detector at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries that can be unambiguously attributed to perturbative QCD processes have been observed for the first time. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Ist Nazl Fis Nucl, Cosenza, Italy. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Chonnam Natl Univ, Kwangju, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, D-2000 Hamburg, Germany. DESY, Zeuthen, Germany. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Exp Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum Julich, Inst Kernphys, D-5170 Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow Engn Phys Inst, Moscow 115409, Russia. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. NIKHEF, Amsterdam, Netherlands. Univ Amsterdam, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford OX1 2JD, England. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Ist Nazl Fis Nucl, Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-5900 Siegen, Germany. Tel Aviv Univ, Sch Phys, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Fac Sci 2, I-10125 Turin, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Warsaw Univ, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT USA. York Univ, Dept Phys, Toronto, ON M3J 2R7, Canada. IROE, Florence, Italy. RP Breitweg, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Solomin, Anatoly/C-3072-2016; dusini, stefano/J-3686-2012; Goncalo, Ricardo/M-3153-2016; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016; De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Bashkirov, Vladimir/A-4818-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Dementiev, Roman/K-7201-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Tassi, Enrico/K-3958-2015 OI PAGANIS, STATHES/0000-0002-1950-8993; dusini, stefano/0000-0002-1128-0664; Goncalo, Ricardo/0000-0002-3826-3442; Graciani Diaz, Ricardo/0000-0001-7166-5198; Bailey, David C/0000-0002-7970-7839; Kasemann, Matthias/0000-0002-0429-2448; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Arneodo, Michele/0000-0002-7790-7132; Abbiendi, Giovanni/0000-0003-4499-7562; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240; De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; NR 34 TC 50 Z9 50 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 25 PY 2000 VL 481 IS 2-4 BP 199 EP 212 DI 10.1016/S0370-2693(00)00430-5 PG 14 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 320QA UT WOS:000087410800008 ER PT J AU Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, C Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Paganis, S Sampson, S Schmidke, WB Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Piotrzkowski, K Przybycien, MB Stopa, P Zawiejski, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Dannheim, D Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Benen, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH Lee, SB Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, I de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, I Stroili, R Voci, C Adamczyk, L Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Catterall, C Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S AF Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, C Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Irrgang, P Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Paganis, S Sampson, S Schmidke, WB Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Piotrzkowski, K Przybycien, MB Stopa, P Zawiejski, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Szuba, D Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Dannheim, D Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Benen, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH Lee, SB Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Dementiev, RK Ermolov, PF Golubkov, YA Katkov, II Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Vlasov, NN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Grijpink, S Koffeman, E Kooijman, P Schagen, S van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Vossebeld, J Wiggers, I de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, I Stroili, R Voci, C Adamczyk, L Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Sacchi, R Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Catterall, C Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S TI Measurement of inclusive (D-s(+/-)) photoproduction at HERA SO PHYSICS LETTERS B LA English DT Article ID DEEP-INELASTIC SCATTERING; LUND MONTE-CARLO; CROSS-SECTIONS; STRANGENESS SUPPRESSION; PARTON DISTRIBUTIONS; JET FRAGMENTATION; E+E ANNIHILATION; HERA; PHYSICS; PROTON AB The first measurement of inclusive D-s(+/-) photoproduction at HERA has been performed with the ZEUS detector for photon-proton centre-of-mass energies; 130 < W < 280 GeV The measured cross section for 3 < p(perpendicular to)(Ds) < 12 GeV and \eta(Ds)\ < 1.5 is sigma(ep-->DsX) = 3.79 +/- 0.59(stat.)(-0.46)(+0.26)(syst.) +/- 0.94(br.) nb, where the last error arises from the uncertainty in the D-s(+/-) decay branching ratio. The measurements are compared with inclusive D*(+/-) photoproduction cross sections in the same kinematic region and with QCD calculations. The D-s(+/-) cross sections lie above a fixed-order next-to-leading order calculation and agree better with a tree-level O(alpha alpha(s)(3)) calculation that was tuned to describe the ZEUS D* (+/-) cross sections. The ratio of D-s(+/-) to D*(+/-) cross sections is 0.41 +/- 0.07(stat.)(-0.05)(+0.03)(syst.) +/- 0.10 (br.). From this ratio, the strangeness-suppression factor in charm photoproduction, within the LUND string fragmentation model, has been calculated to be gamma(s)= 0.27 +/- 0.05 +/- 0.07(br.). The cross-section ratio and gamma(s) are in good agreement with those obtained in charm production in e(+)e(-) annihilation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Ist Nazl Fis Nucl, Cosenza, Italy. Chonnam Natl Univ, Kwangju, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, D-2000 Hamburg, Germany. DESY, Zeuthen, Germany. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Exp Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum Julich, Inst Kernphys, D-5170 Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ H3A 2T5, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow Phys Engn Inst, Moscow, Russia. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. NIKHEF H, NL-1009 DB Amsterdam, Netherlands. Univ Amsterdam, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford OX1 2JD, England. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Ist Nazl Fis Nucl, I-00185 Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-5900 Siegen, Germany. Tel Aviv Univ, Sch Phys, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Fac Sci 2, Turin, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. York Univ, Dept Phys, Toronto, ON M3J 2R7, Canada. CNR, IROE, I-50127 Florence, Italy. RP Breitweg, J (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Bashkirov, Vladimir/A-4818-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Solomin, Anatoly/C-3072-2016; Proskuryakov, Alexander/J-6166-2012; Dementiev, Roman/K-7201-2012; Katz, Uli/E-1925-2013; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016; dusini, stefano/J-3686-2012; Goncalo, Ricardo/M-3153-2016; Graciani Diaz, Ricardo/I-5152-2016 OI De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240; dusini, stefano/0000-0002-1128-0664; Goncalo, Ricardo/0000-0002-3826-3442; Graciani Diaz, Ricardo/0000-0001-7166-5198 NR 52 TC 38 Z9 39 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 25 PY 2000 VL 481 IS 2-4 BP 213 EP 227 DI 10.1016/S0370-2693(00)00431-7 PG 15 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 320QA UT WOS:000087410800009 ER PT J AU Miller, GA Brodsky, SJ Karliner, M AF Miller, GA Brodsky, SJ Karliner, M TI Coherent contributions of nuclear mesons to electroproduction and the HERMES effect SO PHYSICS LETTERS B LA English DT Article ID LIGHT-FRONT; MATTER; PHYSICS AB We show that nuclear sigma,omega, and pi mesons can contribute coherently to enhance the electroproduction cross section on nuclei for longitudinal virtual photons at low Q(2) while depleting the cross section for transverse photons. We are able to describe recent HERMES inelastic lepton-nucleus scattering data at low Q(2) and small x using photon-meson and meson-nucleus couplings which are consistent with (but not determined by) existing constraints from meson decay widths, nuclear structure, deep inelastic scattering, and lepton pair production data. We find that while nuclear-coherent pion currents are not important for the present data, they could be observed at different kinematics. Our model for coherent meson electroproduction requires the assumption of mesonic currents and couplings which can be verified in separate experiments. The observation of nuclear-coherent mesons in the final state would verify our theory and allow the identification of a specific dynamical mechanism for higher-twist processes. (C) 2000 Published by Elsevier Science B.V, All rights reserved. C1 Univ Washington, Dept Phys, Seattle, WA 98195 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. RP Univ Washington, Dept Phys, Seattle, WA 98195 USA. EM miller@nucthy.phys.washington.edu; sjbth@slac.stanford.edu; marek@proton.tau.ac.il NR 24 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 EI 1873-2445 J9 PHYS LETT B JI Phys. Lett. B PD MAY 25 PY 2000 VL 481 IS 2-4 BP 245 EP 252 DI 10.1016/S0370-2693(00)00433-0 PG 8 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 320QA UT WOS:000087410800013 ER PT J AU Kauzlarich, S Morss, LR AF Kauzlarich, S Morss, LR TI Proceedings of the Twenty-Second Rare Earth Research Conference, Argonne, Illinois - July 11-15, 1999 - Preface SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Editorial Material C1 Univ Calif Davis, Davis, CA 95616 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Kauzlarich, S (reprint author), Univ Calif Davis, Davis, CA 95616 USA. RI Kauzlarich, Susan/H-1439-2011 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP XII EP XII DI 10.1016/S0925-8388(00)00591-0 PG 1 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600002 ER PT J AU Morss, LR Lewis, MA Richmann, MK Lexa, D AF Morss, LR Lewis, MA Richmann, MK Lexa, D TI Cerium, uranium, and plutonium behavior in glass-bonded sodalite, a ceramic nuclear waste form SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE ceramic nuclear waste; glass-bonded sodalite; cerium; uranium; plutonium AB Glass-bonded sodalite is being developed as a ceramic waste form (CWF) to immobilize radioactive fission products, actinides, and salt residues from electrometallurgical treatment of spent nuclear reactor fuel. The CWF consists of about 75 mass% sodalite, 25 mass% glass, and small amounts of other phases. This paper presents some results and interpretation of physical measurements to characterize the CWF structure, and dissolution tests to measure the release of matrix components and radionuclides from the waste form. Tests have been carried out with specimens of the CWF that contain rare earths at concentrations similar to those expected in the waste form. Parallel tests have been carried out on specimens that have uranium or plutonium as well as the rare earths at concentrations similar to those expected in the waste forms; in these specimens UCl3 forms UO2 and PuCl3 forms PuO2. The normalized releases of rare earths in dissolution tests were found to be much lower than those of matrix elements (B, Si, Al, Na). When there is no uranium in the CWF, the release of cerium is two to ten times lower than the release of the other rare earths. The low release of cerium may be due to its tetravalent state in uranium-free CWF. However, when there is uranium in the CWF, the release of cerium is similar to that of the other rare earths. This trivalent behavior of cerium is attributed to charge transfer or covalent interactions among cerium, uranium, and oxygen in (U,Ce)O-2. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. RP Morss, LR (reprint author), Argonne Natl Lab, Div Chem Technol, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 19 TC 13 Z9 13 U1 1 U2 14 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 42 EP 48 DI 10.1016/S0925-8388(00)00601-0 PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600007 ER PT J AU Loong, CK Ozawa, M AF Loong, CK Ozawa, M TI The role of rare earth dopants in nanophase zirconia catalysts for automotive emission control SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE rare earth dopants; ZrO2; automotive exhaust; emission control ID ZRO2-CEO2 SOLID-SOLUTIONS; PHASE-TRANSITION; HEAT-TREATMENT; SCATTERING; CERIA; TEMPERATURE; NEUTRON; DIFFRACTION; DIAGRAM; SYSTEM AB Rare earth (RE) modification of automotive catalysts (e.g., ZrO2) for exhaust gas treatment results in outstanding improvement of the structural stability, catalytic functions and resistance to sintering at high temperatures. Owing to the low redox potential of nonstoichiometric CeO2, oxygen release and intake associated with the conversion between the 3+ and 4+ oxidation states of the Ce ions in Ce-doped ZrO2 provide the oxygen storage capacity that is essentially to effective catalytic functions under dynamic air-to-fuel ratio cycling. Doping tripositive RE ions such as La and Nd in ZrO2, on the other hand, introduces oxygen vacancies that affect the electronic and ionic conductivity. These effects, in conjunction with the nanostructure and surface reactivity of the fine powders, present a challenging problem in the development of better ZrO2-containing three-way catalysts. We have carried out in situ small- to wide-angle neutron diffraction at high temperatures and under controlled atmospheres to study the structural phase transitions, sintering behavior, and Ce3+<->Ce4+ redox process. We found substantial effects due to RE doping on the nature of aggregation of nanoparticles, defect formation, crystal phase transformation, and metal-support interaction in ZrO2 catalysts for automotive emission control. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Nagoya Inst Technol, Tajimi 5070071, Japan. RP Loong, CK (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 33 TC 30 Z9 39 U1 1 U2 18 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 60 EP 65 DI 10.1016/S0925-8388(00)00607-1 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600010 ER PT J AU Jensen, MP Morss, LR Beitz, JV Ensor, DD AF Jensen, MP Morss, LR Beitz, JV Ensor, DD TI Aqueous complexation of trivalent lanthanide and actinide cations by N,N,N ',N '-tetrakis(2-pyridylmethyl)ethylenediamine SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE americium; lanthanides; stability constants; complexation; soft donors ID SOLUTION CHEMISTRY; CONSTANTS; RADII AB The aqueous complexation reactions of trivalent lanthanide and actinide cations with the hexadentate ligand N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) have been characterized using potentiometric and spectroscopic techniques in 0.1 M NaClO4. At 25 degrees C, the stability constant of Am(TPEN)(3+) is two orders of magnitude larger than that of Sm(TPEN)(3+), reflecting the stronger interactions of the trivalent actinide cations with softer ligands as compared to lanthanide cations. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. Tennessee Technol Univ, Dept Chem, Cookeville, TN 38505 USA. RP Jensen, MP (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Jensen, Mark/G-9131-2012 OI Jensen, Mark/0000-0003-4494-6693 NR 19 TC 62 Z9 62 U1 1 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 137 EP 141 DI 10.1016/S0925-8388(00)00620-4 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600021 ER PT J AU Runde, W Van Pelt, C Allen, PG AF Runde, W Van Pelt, C Allen, PG TI Spectroscopic characterization of trivalent f-element (Eu, Am) solid carbonates SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE europium; carbonate; fluorescence; EXAFS ID HYDRATION NUMBER; LUMINESCENCE; COMPLEXATION; IONS; LANTHANIDE; EUROPIUM; FLUORESCENCE AB Solubility studies show that trivalent f-element carbonate compounds are the predominant solids that primarily limit the soluble metal ion concentration under environmental conditions. We systematically investigated the spectroscopic characteristics of a series of solid f-element (Eu and Am-243) carbonates. Varying pH, ionic strength, and carbonate concentration results in the formation of M(OH)(3), MOHCO3, M-2(CO3)(3). nH(2)O, and NaM(CO3)(2). nH(2)O, where M=Eu(III) or Am(III). Solids were characterized by FTIR, fluorescence, and EXAFS spectroscopies that determined and confirmed the coordination environment, and by their individual X-ray diffraction powder patterns. The number of coordinated crystal waters was determined to be 2-3 for Eu-2(CO3)(3). nH(2)O and 5 for NaEu(CO3)(2). nH(2)O using thermogravimetric/differential thermal analysis and fluorescence lifetime. We report studies of the fluorescence of Am(III) and the effect of carbonate coordination on the D-5(1) --> F-7(1) transition. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Lawrence Livermore Natl Lab, Seaborg Inst Transactinium Sci, Livermore, CA 94551 USA. RP Runde, W (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, MS J514, Los Alamos, NM 87545 USA. NR 49 TC 23 Z9 25 U1 1 U2 17 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 182 EP 190 DI 10.1016/S0925-8388(00)00665-4 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600030 ER PT J AU Gschneidner, KA Pecharsky, VK Pecharsky, AO Ivtchenko, VV Levin, EM AF Gschneidner, KA Pecharsky, VK Pecharsky, AO Ivtchenko, VV Levin, EM TI The nonpareil R-5(SixGe1-x)(4) phases SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE rare earth-silicide-germanides; magnetocaloric effect; magnetic properties; crystal structures; electronic specific heat constant; Debye temperature ID MAGNETIC REFRIGERATION; GD-5(SI2GE2); TRANSITION; GD-5(SI1.8GE2.2); FIELD AB The R-5(SixGe1-x)(4) materials have been known for over 30 years, but only in the last few years has their uniqueness become evident. Their exotic behaviors include a simultaneous first-order crystallographic-magnetic phase transition, the giant magnetocaloric effect, enhanced Curie temperature due to the existence of (Si,Ge)-(Si,Ge) bond pairs, and the absence of the magnetic contribution to the heat capacity below 10 K of ferrimagnetic Nd5Ge4, which orders at 55 K. These behaviors were observed in our studies of the phase relationships, crystallography, and the electrical, magnetic and thermal properties of the pseudo-binary 5:4 compounds with R=La, Nd, Gd, Dy and Lu. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Gschneidner, KA (reprint author), Iowa State Univ Sci & Technol, Ames Lab, 255 Spedding, Ames, IA 50011 USA. NR 26 TC 91 Z9 91 U1 0 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 214 EP 222 DI 10.1016/S0925-8388(00)00747-7 PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600034 ER PT J AU Fisher, IR Islam, Z Zarestky, J Stassis, C Kramer, MJ Goldman, AI Canfield, PC AF Fisher, IR Islam, Z Zarestky, J Stassis, C Kramer, MJ Goldman, AI Canfield, PC TI Magnetic properties of icosahedral R-Mg-Zn quasicrystals (R=Y, Tb, Dy, Ho and Er) SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE quasicrystals; crystal growth; magnetic measurements; spin glass ID QUASI-CRYSTALS; TERNARY MELT; = Y; GROWTH AB Large (up to 0.5 cm(3)) single grains of icosahedral R-Mg-Zn quasicrystals (R=Y, Tb, Dy, Ho and Er) have been grown via a self-flux technique. The samples have a composition of approximately R9Mg34Zn57, and are extremely well-ordered, with little or no evidence of phason strain. These samples have allowed a detailed investigation of the magnetic behaviour of local 4f moments in a quasiperiodic environment. Neutron scattering experiments using powdered single-grains show no evidence for long range magnetic order in the R-Mg-Zn quasicrystals. However, magnetization and magnetic susceptibility measurements indicate a spin-glass state, with freezing temperatures T-f = 5.8, 3.6, 2.0 and 1.3 K for R = Tb, Dy, Ho and Er respectively. Deviations from a Curie-Weiss temperature dependence of the susceptibility are small, and only occur for temperatures up to 5 K above T-f, indicating the absence of any significant cluster glass behaviour. In addition, the rare earth dilution series (Y1-xGdx)-Mg-Zn have lower freezing temperatures than (Y1-xTbx)-Mg-Zn, despite the larger de Gennes factor of Gd3+ over Tb3+, indicating that crystal electric fields play a significant role in the freezing phenomenon. This difference between Heisenberg and non-Heisenberg moments is further explored via several (Gd1-xRx)-Mg-Zn pseudo-ternary quasicrystal series. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Dept Mat Sci & Engn, Ames, IA 50011 USA. RP Fisher, IR (reprint author), Iowa State Univ, Dept Phys & Astron, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 16 TC 11 Z9 12 U1 0 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 223 EP 227 DI 10.1016/S0925-8388(00)00635-6 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600035 ER PT J AU Thompson, JD Hegger, H Louca, D Kwei, GH Movshovich, R Petrovic, C Sarrao, JL AF Thompson, JD Hegger, H Louca, D Kwei, GH Movshovich, R Petrovic, C Sarrao, JL TI Competing ground states in heavy-fermion materials SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, IL SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE pressure; thermal expansion; heavy fermions; Kondo effects; neutron diffraction; phase transitions ID LIQUID BEHAVIOR; SUPERCONDUCTIVITY; CERH2SI2; PHASE; PRESSURE; CECU2SI2; ALLOYS; FLUCTUATIONS; DISORDER; LATTICE AB Competing interactions in the presence of coupled spin, charge, and lattice degrees of freedom in heavy-fermion materials lead to a near degeneracy of ground states in some systems. A small perturbation in unit-cell volume or composition subsequently can produce a qualitative change in the ground state, for example, from magnetically ordered to superconducting, with, in some instances, the appearance of a non-Fermi-liquid (NFL) state near their boundary. We have studied two heavy-fermion materials, CeCu2Si2 and CeRh2Si2, which illustrate these behaviors. Measurements of the atomic structure of CeCu2+xSi2 as a function of x suggest that structural inhomogeneity may influence the preferred ground state and the existence of NFL behavior in this material. Thermal expansion measurements on CeRh2Si2 as a function of pressure reveal the evolution of spin-lattice coupling as the balance between RKKY and Kondo interactions is tuned by small volume changes. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Thompson, JD (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM jdt@mst.lanl.gov RI Petrovic, Cedomir/A-8789-2009 OI Petrovic, Cedomir/0000-0001-6063-1881 NR 33 TC 3 Z9 3 U1 2 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 EI 1873-4669 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 239 EP 244 DI 10.1016/S0925-8388(00)00666-6 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600038 ER PT J AU Wiener, TA Fisher, IR Canfield, PC AF Wiener, TA Fisher, IR Canfield, PC TI The magnetic characteristics of the Tb(Ni1-xCox)(2)Ge-2 system SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE magnetically ordered materials; crystal growth; magnetisation ID NEUTRON AB The compounds TbNi2Ge2 and TbCo2Ge2 both crystallize with the ThCr2Si2 structure. TbNi2Ge2 has a complex H-T phase diagram while TbCo2Ge2 has a much simpler, though disputed phase diagram. In order to investigate the effects on the magnetism of TbNi2Ge2 due to cobalt substitution, single crystals of Tb(Ni1-xCox)(2)Ge-2 with x ranging from 0 to 1 have been grown from a psuedoternary melt. We have traced the Neel and Weiss temperatures as a function of cobalt concentration, x. Close to x=0.5, the Weiss temperature is positive, indicating predominately ferromagnetic interactions (in contrast to x<0.4 and x>0.6 for which the Weiss temperatures are negative), chi(T approximate to TN) is a maximum and the critical field for metamagnetism is a minimum. Nevertheless, the compound orders antiferromagnetically, similar to all other members of the dilution series. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Wiener, TA (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 6 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 289 EP 292 DI 10.1016/S0925-8388(00)00587-9 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600048 ER PT J AU Skanthakumar, S Soderholm, L Movshovich, R AF Skanthakumar, S Soderholm, L Movshovich, R TI Magnetic properties of Dy in Pb2Sr2DyCu3O8 SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE high-T-c superconductors; crystal and ligand fields; magnetically ordered materials ID R = LA; SINGLE-CRYSTALS; OXIDATION-STATE; ORDER; PR; ND; TB; PB2SR2PRCU3O8; SUPERCONDUCTORS; DYBA2CU3O7 AB Superconductivity can be induced at high temperatures in Pb2Sr2RCu3O8 (R, rare earth) by partially doping Ca2+ for R3+. In order to understand the interplay between magnetism and superconductivity, the magnetic properties of the parent compounds, Pb2Sr2RCu3O8 have been studied. The work presented here includes magnetic susceptibility and specific heat measurements on R=Dy and extends our previous studies on R=Ce, Pr, Tb, Ho and Er. Specific heat experiments suggest that the Dy ions order magnetically with an ordering temperature of 1.3 K. The magnetic susceptibility data are in good agreement with the susceptibility calculated using crystal-field parameters that are extrapolated from previous modeling of the R=Er and Ho analogs of this series. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Skanthakumar, S (reprint author), Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. NR 35 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 298 EP 302 DI 10.1016/S0925-8388(00)00589-2 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600050 ER PT J AU Li, ST Liu, GK Liu, H Fernandez, FE AF Li, ST Liu, GK Liu, H Fernandez, FE TI Effects of thermal annealing on spectroscopic properties of Eu3+ in Sr1-xBxNb2O6 films SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE Eu3+ in SBN film; laser spectroscopy; thermal annealing ID GLASS AB Thermal annealing influence on properties of strontium-barium niobate (SBN) films doped with Eu3+ has been studied using laser spectroscopic methods. The Stark splittings of the D-5(1) state and all the F-7(J) states are well resolved only in the spectra from the annealed films, whereas the spectra of Eu3+ in the as-deposited film is similar to that in amorphous phases, Non-resonant fluorescence line narrowing (FLN) is observed only for the annealed film, which indicates a correlation between the energy levels of Eu3+ in inhomogeneous line broadening. Annealing-induced crystallization of the as-deposited film also increases the D-5(0) fluorescence lifetime and allows hyperfine spectral hole burning. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Univ Puerto Rico, Dept Phys, Mayaguez, PR 00681 USA. RP Liu, GK (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. OI Fernandez, Felix/0000-0002-0710-6751 NR 16 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 360 EP 363 DI 10.1016/S0925-8388(00)00641-1 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600062 ER PT J AU Morrison, HG Assefa, Z Haire, RG Peterson, JR AF Morrison, HG Assefa, Z Haire, RG Peterson, JR TI Raman and X-ray diffraction studies of terbium trichloride: phase characterization and temperature relationship SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE chemical synthesis; X-ray diffraction; optical properties; phase transitions; inelastic light scattering ID RARE-EARTH TRICHLORIDES AB We have used phonon Raman spectrophotometry as a rapid and convenient tool, complimentary to X-ray diffraction, for investigating the polymorphism of TbCl3. In the literature one finds references to the polymorphism of TbCl3, but there is some confusion regarding the structural identity and temperature relationship of the different phases reported. In the present work TbCl3 was prepared via reaction of Tb4O7 and anhydrous HCl gas. Its Raman spectrum was acquired at room temperature and pressure (RTP) and correlated with the results of X-ray diffraction analysis to confirm the PuBr3-type orthorhombic structure. This TbCl3 structure was then monitored as a function of temperature, including after being quenched from the molten state. From our Raman and X-ray results, a phase transition occurred at about 510 degrees C to a tentatively assigned tetragonal structure, which appeared stable up to the melting point (582 degrees C). Additional annealing studies down to about 250 degrees C resulted in the observation of only the RTP form. No evidence for a UCl3-type hexagonal or AlCl3-type monoclinic structure was found in this work, though they are common forms of other lanthanide trichlorides. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Transuranium Res Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Peterson, JR (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 16 TC 6 Z9 9 U1 1 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 440 EP 444 DI 10.1016/S0925-8388(00)00622-8 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600075 ER PT J AU Wiener, TA Canfield, PC AF Wiener, TA Canfield, PC TI Magnetic phase diagram of flux-grown single crystals of CeSb SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE magnetically ordered materials; crystal growth; electronic transport; magnetization; phase diagrams AB CeSb is well known for having a particularly complex H-T phase diagram. Most of the studies on this compound have been performed on crystals produced by a direct reaction technique. Here, we report on crystals of CeSb grown from a high temperature melt utilizing a third element, in this case tin, as a flux. The crystals are of exceptionally high quality, having a residual resistance ratio rho(300 K)/rho(2 K) > 400. We present detailed magnetization and resistivity data performed in order to map the H-T phase diagram which has never been fully determined by thermodynamic and transport measurements. The resulting phase diagram is exceptionally complex, corresponds well with the results of neutron scattering studies, and reveals at least two new ordered states. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Wiener, TA (reprint author), Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RI Canfield, Paul/H-2698-2014 NR 12 TC 4 Z9 4 U1 3 U2 15 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 505 EP 508 DI 10.1016/S0925-8388(00)00636-8 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600083 ER PT J AU Williams, CW Antonio, MR Soderholm, L AF Williams, CW Antonio, MR Soderholm, L TI The formation and stability of [EuP5W30O110](12-) and [AmP5W30O110](12-) SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 22nd Rare Earth Research Conference CY JUL 11-15, 1999 CL ARGONNE NATL LAB, ARGONNE, ILLINOIS SP Argonne Natl Lab, Rare Earth Res Conference Inc, Arris Int Corp, Bracco Res USA, Petr Res Fund, Amer Chem Soc HO ARGONNE NATL LAB DE [EuP5W30O110](12-); [AmP5W30O110](12-); formation; stability ID X-RAY-ABSORPTION; FINE-STRUCTURE; HETEROPOLYANION (12-); ACTINIDE COMPOUNDS; COORDINATION; POTENTIALS; LANTHANIDE; VALENCE; CATIONS AB A comparison of the standard reduction potentials of Eu3+ and Am3+, as well as their similar ionic radii, suggest that Am in the Preyssler anion, [AmP5W30O110](12-), may be reduced under an applied potential. However, cyclic voltammetric studies performed in a noncomplexing electrolyte, together with XANES and EXAFS data, consistently demonstrate that Am is trivalent when encrypted in [AmP5W30O110](12-) There is no evidence of Am3+ reduction, even at the lowest potentials probed. A comparison of bond distances of the trivalent Am analog, determined from EXAFS spectroscopy, with those of other tetravalent f ions shows a correlation with ionic radii that appears independent of the charge on the ion. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Williams, CW (reprint author), Argonne Natl Lab, Div Chem, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 26 TC 14 Z9 14 U1 1 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD MAY 24 PY 2000 VL 303 BP 509 EP 513 DI 10.1016/S0925-8388(00)00637-X PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 318YQ UT WOS:000087312600084 ER PT J AU O'Brien, JC Stickney, JT Porter, MD AF O'Brien, JC Stickney, JT Porter, MD TI Self-assembled double-stranded DNA (dsDNA) microarrays for protein : dsDNA screening using atomic force microscopy SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GOLD SURFACES; MONOLAYERS; ARRAYS; DISULFIDES C1 US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Dept Biochem Biophys & Mol Biol, Ames, IA 50011 USA. RP Porter, MD (reprint author), US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. NR 13 TC 52 Z9 54 U1 0 U2 6 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 MAY 24 PY 2000 VL 122 IS 20 BP 5004 EP 5005 DI 10.1021/ja000411f PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 318CQ UT WOS:000087266700032 ER PT J AU Alexov, E Miksovska, J Baciou, L Schiffer, M Hanson, DK Sebban, P Gunner, MR AF Alexov, E Miksovska, J Baciou, L Schiffer, M Hanson, DK Sebban, P Gunner, MR TI Modeling the effects of mutations on the free energy of the first electron transfer from Q(A)(-) to Q(B) in photosynthetic reaction centers SO BIOCHEMISTRY LA English DT Article ID BACTERIAL REACTION CENTERS; RHODOBACTER-SPHAEROIDES R-26; PROTON-TRANSFER PATHWAYS; SECONDARY QUINONE Q(B); RHODOPSEUDOMONAS-VIRIDIS; BINDING-SITE; CONFORMATIONAL FLEXIBILITY; CHARGE RECOMBINATION; ROTAMER PREFERENCES; H+ BINDING AB Numerical calculations of the free energy of the first electron transfer in genetically modified reaction centers from Rhodobacter (Rb.) sphaeroides and Rb. capsulatus were carried out from pH 5 to 11. The multiconformation continuum electrostatics (MCCE) method allows side chain, ligand, and water reorientation to be embedded in the calculations of the Boltzmann distribution of cofactor and amino acid ionization states. The mutation sites whose effects have been modeled are L212, and L213 (the L polypeptide) and two in the M polypeptide, M43(44) and M231(233) in Rb. capsulatus (Rb. sphaeroides). The results of the calculations were compared to the experimental data, and very good agreement was found especially at neutral pH. Each mutation removes or introduces ionizable residues, but the protein maintains a net charge close to that in native RCs through ionization changes in nearby residues. This reduces the effect of mutation and makes the changes in state free energy smaller than would be found in a rigid protein. The state energy of Q(A)(-)Q(B) and Q(A)Q(B)(-) states have contributions from interactions among the residues as well as with the quinone which is ionized. For example, removing L213Asp, located in the Q(B) pocket, predominantly changes the free energy of the Q(A)(-)Q(B) state, where the Asp is ionized in native RCs rather than the Q(A)Q(B)(-) state, where it is neutral. Side chain, hydroxyl, and water rearrangements due to each of the mutations have also been calculated showing water occupancy changes during the Q(A)(-) to Q(B) electron transfer. C1 CUNY City Coll, Dept Phys, New York, NY 10031 USA. CNRS, Ctr Genet Mol, F-91198 Gif Sur Yvette, France. Argonne Natl Lab, Div Biosci, Argonne, IL 60439 USA. RP Gunner, MR (reprint author), CUNY City Coll, Dept Phys, 138 St & Convent Ave, New York, NY 10031 USA. EM gunner@sci.ccny.cuny.edu NR 72 TC 43 Z9 45 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 23 PY 2000 VL 39 IS 20 BP 5940 EP 5952 DI 10.1021/bi9929498 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 320KE UT WOS:000087399700003 PM 10821665 ER PT J AU Xu, WD Angelis, K Danielpour, D Haddad, MM Bischof, O Campisi, J Stavnezer, E Medrano, EE AF Xu, WD Angelis, K Danielpour, D Haddad, MM Bischof, O Campisi, J Stavnezer, E Medrano, EE TI Ski acts as a co-repressor with Smad2 and Smad3 to regulate the response to type beta transforming growth factor SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE ski oncogene; transcription; melanoma ID TGF-BETA; TRANSCRIPTIONAL REPRESSION; MELANOMA-CELLS; DNA-BINDING; V-SKI; SKELETAL-MUSCLE; ONCOGENE; RECEPTOR; GENE; MAD AB The c-ski protooncogene encodes a transcription factor that binds DNA only in association with other proteins. To identify co-binding proteins, we performed a yeast two-hybrid screen. The results of the screen and subsequent co-immunoprecipitation studies identified Smad2 and Smad3, two transcriptional activators that mediate the type beta transforming growth factor (TGF-beta) response, as Ski-interacting proteins. In Ski-transformed cells, all of the Ski protein was found in Smad3-containing complexes that accumulated in the nucleus in the absence of added TGF-beta. DNA binding assays showed that Ski, Smad2, Smad3, and Smad4 form a complex with the Smad/Ski binding element GTCTAGAC (SBE). Ski repressed TGF-beta-induced expression of 3TP-Lux, the natural plasminogen activator inhibitor 1 promoter and of reporter genes driven by the SEE and the related CAGA element. In addition, Ski repressed a TGF-beta-inducible promoter containing AP-1 (TRE) elements activated by a combination of Smads, Fos, and/or Jun proteins. Ski also repressed synergistic activation of promoters by combinations of Smad proteins but failed to repress in the absence of Smad4. Thus, Ski acts in opposition to TCF-beta-induced transcriptional activation by functioning as a Smad-dependent co-repressor. The biological relevance of this transcriptional repression was established by showing that overexpression of Ski abolished TGF-beta-mediated growth inhibition in a prostate-derived epithelial cell line. C1 Case Western Reserve Univ, Dept Biochem, Cleveland, OH 44106 USA. Baylor Coll Med, Huffington Ctr Aging, Houston, TX 77030 USA. Baylor Coll Med, Dept Mol & Cellular Biol, Houston, TX 77030 USA. Baylor Coll Med, Dept Dermatol, Houston, TX 77030 USA. Vet Affairs Med Ctr, Houston, TX 77030 USA. Case Western Reserve Univ, Ctr Canc, Cleveland, OH 44106 USA. Case Western Reserve Univ, Dept Pharmacol, Cleveland, OH 44106 USA. Lawrence Berkeley Natl Lab, Dept Cell & Mol Biol, Berkeley, CA 94720 USA. RP Medrano, EE (reprint author), Case Western Reserve Univ, Dept Biochem, 2109 Adelbert Rd, Cleveland, OH 44106 USA. FU NCI NIH HHS [CA-43600, P30 CA043703, R01 CA043600]; NIA NIH HHS [AG-09990, AG-3663] NR 45 TC 147 Z9 155 U1 1 U2 7 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 23 PY 2000 VL 97 IS 11 BP 5924 EP 5929 DI 10.1073/pnas.090097797 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 319BG UT WOS:000087318700047 PM 10811875 ER PT J AU Ferguson, AT Evron, E Umbricht, CB Pandita, TK Chan, TA Hermeking, H Marks, JR Lambers, AR Futreal, PA Stampfer, MR Sukumar, S AF Ferguson, AT Evron, E Umbricht, CB Pandita, TK Chan, TA Hermeking, H Marks, JR Lambers, AR Futreal, PA Stampfer, MR Sukumar, S TI High frequency of hypermethylation at the 14-3-3 sigma locus leads to gene silencing in breast cancer SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID TRANSCRIPTIONAL REPRESSION; TELOMERASE ACTIVITY; METHYLATION STATUS; DUCTAL CARCINOMA; RECEPTOR GENE; CHROMOSOME 1P; CPG ISLAND; PROGRESSION; EXPRESSION; CELLS AB Expression of 14-3-3 sigma (sigma) is induced in response to DNA damage, and causes cells to arrest in G(2), By SAGE (serial analysis of gene expression) analysis, we identified sigma as a gene whose expression is 7-fold lower in breast carcinoma cells than in normal breast epithelium. We verified this finding by Northern blot analysis. Remarkably, sigma mRNA was undetectable in 45 of 48 primary breast carcinomas. Genetic alterations at sigma such as loss of heterozygosity were rare (1/20 informative cases), and no mutations were detected (0/34), On the other hand, hypermethylation of CpG islands in the sigma gene was detected in 91% (75/82) of breast tumors and was associated with lack of gene expression, Hypermethylation of sigma is functionally important, because treatment of sigma-non-expressing breast cancer cell lines with the drug 5-aza-2'-deoxycytidine resulted in demethylation of the gene and synthesis of a mRNA. Breast cancer cells lacking sigma expression showed increased number of chromosomal breaks and gaps when exposed to gamma-irradiation, Therefore, it is possible that loss of sigma expression contributes to malignant transformation by impairing the G(2) cell cycle checkpoint function, thus allowing an accumulation of genetic defects. Hypermethylation and loss of sigma expression are the most consistent molecular alterations in breast cancer identified so far. C1 Johns Hopkins Oncol Ctr, Breast Canc Program, Baltimore, MD 21203 USA. Columbia Univ, Ctr Radiol Res, New York, NY 10032 USA. Duke Univ, Med Ctr, Med Res Ctr, Durham, NC 27710 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Sukumar, S (reprint author), Johns Hopkins Oncol Ctr, Breast Canc Program, 1650 Orleans St,410 BBCRB, Baltimore, MD 21203 USA. FU NCI NIH HHS [CA-24844, T32 CA009630, T32 CA09630, CA48943]; NINDS NIH HHS [R01 NS034746] NR 38 TC 355 Z9 373 U1 1 U2 8 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 23 PY 2000 VL 97 IS 11 BP 6049 EP 6054 DI 10.1073/pnas.100566997 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 319BG UT WOS:000087318700068 PM 10811911 ER PT J AU Brundermann, E Chamberlin, DR Haller, EE AF Brundermann, E Chamberlin, DR Haller, EE TI High duty cycle and continuous terahertz emission from germanium SO APPLIED PHYSICS LETTERS LA English DT Article ID P-GE; LASER AB We measured laser emission from Be-doped Ge crystals with intercontact distances as small as 0.5 mm. An improved heat sink allowed a twofold increase of the laser duty cycle to 5%. We also report the measurements of THz emission from small Be-doped Ge crystals under continuous excitation with volumes as small as 0.5 mm(3). (C) 2000 American Institute of Physics. [S0003-6951(00)03721-9]. C1 Ruhr Univ Bochum, D-44780 Bochum, Germany. Univ Calif Berkeley, Berkeley, CA 94720 USA. Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Brundermann, E (reprint author), Ruhr Univ Bochum, Phys Chem II-NC 7-68, D-44780 Bochum, Germany. RI Bruendermann, Erik/J-7186-2016 OI Bruendermann, Erik/0000-0003-4119-3489 NR 14 TC 47 Z9 48 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 22 PY 2000 VL 76 IS 21 BP 2991 EP 2993 PG 3 WC Physics, Applied SC Physics GA 314QF UT WOS:000087066500005 ER PT J AU Keidar, M Monteiro, OR Brown, IG AF Keidar, M Monteiro, OR Brown, IG TI Plasma drift and nonuniformity effects in plasma immersion ion implantation SO APPLIED PHYSICS LETTERS LA English DT Article ID SURFACE MODIFICATION; MODEL; VACUUM AB Measurements of the ion current collected by a substrate biased to high voltage have been carried out in plasma immersion ion implantation with a filtered vacuum arc plasma source. We have found that the ion saturation current increases with applied voltage and that this effect depends upon the angle of the normal to the substrate with respect to the plasma stream and on the distance of the substrate from the plasma duct exit. We also found that the ion current increases with increasing angle of the normal to the substrate with respect to the plasma stream. A model was developed for the sheath expansion in a nonuniform plasma with substantial ion drift velocity. We find that nonuniformity and high drift velocity lead to a decrease in sheath thickness. In a nonuniform plasma, the ion saturation current increases with applied voltage. The predictions of the model were found to be in good agreement with experiment. (C) 2000 American Institute of Physics. [S0003-6951(00)05421-8]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Keidar, M (reprint author), Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. NR 14 TC 13 Z9 13 U1 1 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 22 PY 2000 VL 76 IS 21 BP 3002 EP 3004 DI 10.1063/1.126559 PG 3 WC Physics, Applied SC Physics GA 314QF UT WOS:000087066500009 ER PT J AU Siegal, MP Tallant, DR Provencio, PN Overmyer, DL Simpson, RL Martinez-Miranda, LJ AF Siegal, MP Tallant, DR Provencio, PN Overmyer, DL Simpson, RL Martinez-Miranda, LJ TI Ultrahard carbon nanocomposite films SO APPLIED PHYSICS LETTERS LA English DT Article ID PULSED-LASER DEPOSITION; AMORPHOUS-CARBON; DIAMOND; HARDNESS AB Modest thermal annealing to 600 degrees C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5%-10%. We report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases similar to 15% due to the development of the nanocomposite structure. (C) 2000 American Institute of Physics. [S0003- 6951(00)04420-X]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Siegal, MP (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM mpsiega@sandia.gov NR 17 TC 50 Z9 51 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0003-6951 EI 1077-3118 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 22 PY 2000 VL 76 IS 21 BP 3052 EP 3054 AR PII [S0003-6951(00)04420-X] DI 10.1063/1.126576 PG 3 WC Physics, Applied SC Physics GA 314QF UT WOS:000087066500026 ER PT J AU Bai, GR Streiffer, SK Baumann, PK Auciello, O Ghosh, K Stemmer, S Munkholm, A Thompson, C Rao, RA Eom, CB AF Bai, GR Streiffer, SK Baumann, PK Auciello, O Ghosh, K Stemmer, S Munkholm, A Thompson, C Rao, RA Eom, CB TI Epitaxial Pb(Mg1/3Nb2/3)O-3 thin films synthesized by metal-organic chemical vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID LEAD MAGNONIOBATE; BEHAVIOR AB Metal-organic chemical vapor deposition was used to prepare Pb(Mg1/3Nb2/3)O-3 (PMN) thin films on (001) SrTiO3 and SrRuO3/SrTiO3 substrates, using solid Mg beta-diketonate as the Mg precursor. Parameters including the precursor ratio in the vapor phase, growth temperature, growth rate, and reaction pressure in the reactor chamber were varied in order to determine suitable growth conditions for producing phase-pure, epitaxial PMN films. A cube-on-cube orientation relationship between the thin film and the SrTiO3 substrate was found, with a (001) rocking curve width of 0.1 degrees, and in-plane rocking-curve width of 0.8 degrees. The root-mean-square surface roughness of a 200-nm-thick film on SrTiO3 was 2 to 3 nm as measured by scanning probe microscopy. The zero-bias dielectric constant and loss measured at room temperature and 10 kHz for a 200-nm-thick film on SrRuO3/SrTiO3 were approximately 1100 and 2%, respectively. The remnant polarization for this film was 16 mu C/cm(2). (C) 2000 American Institute of Physics. [S0003- 6951(00)04321-7]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Rice Univ, Dept Mech Engn & Mat Sci, Houston, TX 77005 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Duke Univ, Dept Mech Engn & Mat Sci, Durham, NC 27708 USA. RP Bai, GR (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Streiffer, Stephen/A-1756-2009; Stemmer, Susanne/H-6555-2011; Eom, Chang-Beom/I-5567-2014; OI Stemmer, Susanne/0000-0002-3142-4696; Thompson, Carol/0000-0003-3832-4855 NR 16 TC 49 Z9 50 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 22 PY 2000 VL 76 IS 21 BP 3106 EP 3108 DI 10.1063/1.126538 PG 3 WC Physics, Applied SC Physics GA 314QF UT WOS:000087066500044 ER PT J AU Monier, C Pearton, SJ Chang, PC Baca, AG Ren, F AF Monier, C Pearton, SJ Chang, PC Baca, AG Ren, F TI Effect of Mg ionization efficiency on performance of Npn AlGaN/GaN heterojunction bipolar transistors SO APPLIED PHYSICS LETTERS LA English DT Article ID P-TYPE GAN; MOLECULAR-BEAM EPITAXY; ELECTRON-MOBILITY; DIFFUSION LENGTH; OHMIC CONTACTS; N-GAN; HETEROSTRUCTURES; LIFETIME AB A drift-diffusion transport model has been used to examine the performance capabilities of AlGaN/GaN Npn heterojunction bipolar transistors (HBTs). Simulations using experimental mobility and lifetime reported in the literature closely reproduce the Gummel plot from the GaN-based HBT structure recently demonstrated. Numerical results have been explored to study the effect of the p-type Mg doping and its incomplete ionization in the base. The high base resistance induced by the deep acceptor level is found to be the cause of limiting current gain values. Increasing the operating temperature of the device activates more carriers in the base. An improvement of the simulated current gain by a factor of 2-4 between 25 and 300 degrees C agrees well with the reported experimental results. A preliminary analysis of high-frequency characteristics indicates substantial progress of predicted rf performances by operating the device at higher temperature due to a reduced extrinsic base resistivity. (C) 2000 American Institute of Physics. [S0003- 6951(00)00221-7]. C1 Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. RP Monier, C (reprint author), Sandia Natl Labs, Livermore, CA 94550 USA. NR 21 TC 17 Z9 17 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 22 PY 2000 VL 76 IS 21 BP 3115 EP 3117 DI 10.1063/1.126541 PG 3 WC Physics, Applied SC Physics GA 314QF UT WOS:000087066500047 ER PT J AU Mielke, SL Srinivasan, J Truhlar, DG AF Mielke, SL Srinivasan, J Truhlar, DG TI Extrapolation and perturbation schemes for accelerating the convergence of quantum mechanical free energy calculations via the Fourier path-integral Monte Carlo method SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-STATE THEORY; PARTITION-FUNCTION; COEFFICIENT; COMPUTATION AB We present two simple but effective techniques designed to improve the rate of convergence of the Fourier path-integral Monte Carlo method for quantum partition functions with respect to the Fourier space expansion length, K, especially at low temperatures. The first method treats the high Fourier components as a perturbation, and the second method involves an extrapolation of the partition function (or perturbative correction to the partition function) with respect to the parameter K. We perform a sequence of calculations at several values of K such that the statistical errors for the set of results are correlated, and this permits extremely accurate extrapolations. We demonstrate the high accuracy and efficiency of these new approaches by computing partition functions for H2O from 296 to 4000 K and comparing to the accurate results of Partridge and Schwenke. (C) 2000 American Institute of Physics. [S0021-9606(00)01320-9]. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Univ Minnesota, Chem Phys Program, Minneapolis, MN 55455 USA. Univ Minnesota, Inst Supercomp, Minneapolis, MN 55455 USA. RP Mielke, SL (reprint author), Johns Hopkins Univ, Dept Chem, Charles & 34th St, Baltimore, MD 21218 USA. RI Mielke, Steven/B-7533-2008; Truhlar, Donald/G-7076-2015 OI Mielke, Steven/0000-0002-1938-7503; Truhlar, Donald/0000-0002-7742-7294 NR 25 TC 27 Z9 27 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 2000 VL 112 IS 20 BP 8758 EP 8764 AR PII [S0021-9606(00)01320-9] DI 10.1063/1.481491 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 310WC UT WOS:000086851200003 ER PT J AU Manaa, MR AF Manaa, MR TI The predissociation mechanism of the (B)over-tilde(2)A ' state of HCO via the conical intersection with the (X)over-tilde(2)A ' state SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACES; HYDROCARBON FLAME BANDS; FLUORESCENCE EXCITATION; TRANSITION; (B)OVER-TILDE(2)A'-(X)OVER-TILDE(2)A'; LIFETIMES; SYMMETRY; SPECTRA; SYSTEM; DCO AB We use large-scale multiconfiguration self-consistent field/configuration interaction calculations to characterize the predissociation mechanism of the (B) over tilde (2)A' state of HCO through conical intersection with the (X) over tilde (2)A' ground state. We locate two regions of intersection: the first represents a highly bent HCO that is 8 kcal/mol energetically lower than the (B) over tilde state minimum, with a barrier height of 26 kcal/mol. Energy points on the (B) over tilde (2)A' potential surface connecting these extrema were also calculated. This region emphatically illustrates the feasibility of a nonradiative decay mechanism consistent with latest experimental findings of purely vibronic coupling mechanism. The second region of intersection represents a confluence of three linear (2)Sigma(+)-(2)Pi states crossings, 53 kcal/mol below the (B) over tilde state minimum. A barrier about 21 kcal/mol above the (B) over tilde state equilibrium structure is located and assigned to the entrance channel of H-CO((3)Pi). (C) 2000 American Institute of Physics. [S0021-9606(00)30420-2]. C1 Univ Calif Lawrence Livermore Natl Lab, Energet Mat Ctr, Livermore, CA 94551 USA. RP Manaa, MR (reprint author), Univ Calif Lawrence Livermore Natl Lab, Energet Mat Ctr, POB 808,L-282, Livermore, CA 94551 USA. NR 33 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 2000 VL 112 IS 20 BP 8789 EP 8793 AR PII [S0021-9606(00)30420-2] DI 10.1063/1.481533 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 310WC UT WOS:000086851200008 ER PT J AU Zanni, MT Davis, AV Frischkorn, C Elhanine, M Neumark, DM AF Zanni, MT Davis, AV Frischkorn, C Elhanine, M Neumark, DM TI Femtosecond stimulated emission pumping: Characterization of the I-2(-) ground state SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HOMONUCLEAR DIATOMIC IONS; POTENTIAL-ENERGY CURVES; I2-(CO2)N CLUSTER IONS; AB-INITIO CALCULATIONS; PHOTOELECTRON-SPECTROSCOPY; RECOMBINATION DYNAMICS; VIBRATIONAL-RELAXATION; CHARGE FLOW; PHOTODISSOCIATION DYNAMICS; MOLECULAR-DYNAMICS AB Femtosecond stimulated emission pumping in combination with femtosecond photoelectron spectroscopy is used to characterize the potential energy function of the I-2(-)((X) over tilde (2)Sigma(u)(+)) ground state up to vibrational energies within 2% of the dissociation limit. The frequency and anharmonicity of this state are measured at a series of vibrational energies up to 0.993 eV by coherently populating a superposition of ground state vibrational levels using femtosecond stimulated emission pumping, and monitoring the resulting wave packet oscillations with femtosecond photoelectron spectroscopy. The dissociative I-2(-)((A) over tilde' (2)Pi(g,1/2)) state is used for intermediate population transfer, allowing efficient population transfer to all ground state levels. Using the measured frequencies and anharmonicities, the (X) over tilde (2)Sigma(u)(+) state has been fit to a modified Morse potential with the beta-parameter expanded in a Taylor series, and the bond length, well depth, and upsilon=0-1 fundamental frequency set equal to our previously determined Morse potential [J. Chem. Phys. 107, 7613 (1997)]. At high vibrational energies, the modified potential deviates significantly from the previously determined potential. (C) 2000 American Institute of Physics. [S0021-9606(00)01720-7]. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Paris 11, CNRS, Photophys Mol Lab, F-91405 Orsay, France. RP Zanni, MT (reprint author), Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. RI Zanni, Martin/K-2707-2013; Neumark, Daniel/B-9551-2009 OI Neumark, Daniel/0000-0002-3762-9473 NR 57 TC 23 Z9 23 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 2000 VL 112 IS 20 BP 8847 EP 8854 AR PII [S0021-9606(00)01720-7] DI 10.1063/1.481499 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 310WC UT WOS:000086851200015 ER PT J AU Chau, R Aronson, MC Freeman, EJ Maple, MB AF Chau, R Aronson, MC Freeman, EJ Maple, MB TI Disorder and the quantum critical point in UCu5-xPdx SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID FERMI-LIQUID BEHAVIOR; NMR AB We have measured the magnetization of UCu5-xPdx (x = 0.7, 1, 1.5, 2) in fields H as large as 30 T and for temperatures between 1.4 K and 150 K. A composition- and temperature dependent characteristic field H*(x, T) is identified, which separates two different non-Fermi liquid scaling regimes, present even in zero field. For H greater than or equal to H*(x, T), composition-independent scaling is found, while for H less than or equal to H*(x, T), different exponents are found for each composition. This second phase is centred in temperature and composition around the x = 1, T = 0 critical point, and we argue that it is consistent with the presence of a Griffiths phase. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Calif San Diego, Inst Pure & Appl Phys Sci, La Jolla, CA 92093 USA. Univ Michigan, Harrison M Randall Lab Phys, Ann Arbor, MI 48109 USA. RP Chau, R (reprint author), Lawrence Livermore Natl Lab, POB 5508, Livermore, CA 94550 USA. NR 25 TC 5 Z9 5 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 EI 1361-648X J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD MAY 22 PY 2000 VL 12 IS 20 BP 4495 EP 4502 DI 10.1088/0953-8984/12/20/305 PG 8 WC Physics, Condensed Matter SC Physics GA 323WN UT WOS:000087588100007 ER PT J AU Elliott, DM Rischke, DH AF Elliott, DM Rischke, DH TI Chemical equilibration of quarks and gluons at RHIC and LHC energies SO NUCLEAR PHYSICS A LA English DT Article ID HEAVY-ION COLLISIONS; NUCLEUS-NUCLEUS COLLISIONS; PARTICLE-PRODUCTION; FLAVOR KINETICS; PLASMA; STRANGENESS AB We study chemical equilibration of quarks and gluons in central nuclear collisions at RHIC and LHC energies. The initial quark and gluon densities are taken from earlier studies as well as from recent perturbative QCD estimates and are then evolved via rate equations coupled to longitudinally boost-invariant fluid dynamics. We find that, for RHIC initial conditions, the lifetime of quark-gluon matter is too short in order for the quark and gluon number densities to chemically equilibrate prior to hadronization. In contrast, at LHC energies chemical equilibration is complete before the system hadronizes. Entropy production due to chemical equilibration can be as large as 30%. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Cape Town, Dept Phys, ZA-7701 Rondebosch, South Africa. Brookhaven Natl Lab, RIKEN, Res Ctr, Upton, NY 11973 USA. RP Elliott, DM (reprint author), Univ Cape Town, Dept Phys, ZA-7701 Rondebosch, South Africa. NR 31 TC 35 Z9 35 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 MAY 22 PY 2000 VL 671 IS 1-4 BP 583 EP 608 DI 10.1016/S0375-9474(99)00840-4 PG 26 WC Physics, Nuclear SC Physics GA 316AB UT WOS:000087144200029 ER PT J AU Del Duca, V Kilgore, WB Maltoni, F AF Del Duca, V Kilgore, WB Maltoni, F TI Multi-photon amplitudes for next-to-leading order QCD (vol 566, pg 252, 2000) SO NUCLEAR PHYSICS B LA English DT Correction ID ONE-LOOP CORRECTIONS; GAUGE-THEORIES; HIGGS-BOSON; INFRARED BEHAVIOR; GLUON SCATTERING; COLLIDERS; LHC AB We present the tree-level amplitudes involving one, two and three photons that are required for next-to-leading order QCD calculations of production rates of three final-state particles. We also present the required one-loop amplitudes in terms of previously published results. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Ist Nazl Fis Nucl, Sez Torino, I-10125 Turin, Italy. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Univ Turin, Dipartimento Fis Teor, I-10125 Turin, Italy. RP Del Duca, V (reprint author), Ist Nazl Fis Nucl, Sez Torino, Via P Giuria 1, I-10125 Turin, Italy. RI del duca, vittorio/F-6992-2012 NR 35 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 22 PY 2000 VL 574 IS 3 BP 851 EP 873 DI 10.1016/S0550-3213(99)90663-6 PG 23 WC Physics, Particles & Fields SC Physics GA 318EC UT WOS:000087270100008 ER PT J AU Prakhov, S Tippens, WB Allgower, C Bekrenev, V Berger, E Briscoe, WJ Clajus, M Comfort, JR Craig, K Grosnick, D Huber, GM Isenhower, D Knecht, N Koetke, D Koulbardis, A Kozlenko, N Kruglov, S Kycia, T Lolos, GJ Lopatin, I Manley, DM Marusic, A Manweiler, R McDonald, S Nefkens, BMK Olmsted, J Papandreou, Z Peaslee, D Peterson, GJ Phaisangittisakul, N Pulver, M Ramirez, AF Sadler, ME Shafi, A Slaus, I Spinka, H Stanislaus, S Starostin, A Staudenmaier, HM Supek, I Wong, CW AF Prakhov, S Tippens, WB Allgower, C Bekrenev, V Berger, E Briscoe, WJ Clajus, M Comfort, JR Craig, K Grosnick, D Huber, GM Isenhower, D Knecht, N Koetke, D Koulbardis, A Kozlenko, N Kruglov, S Kycia, T Lolos, GJ Lopatin, I Manley, DM Marusic, A Manweiler, R McDonald, S Nefkens, BMK Olmsted, J Papandreou, Z Peaslee, D Peterson, GJ Phaisangittisakul, N Pulver, M Ramirez, AF Sadler, ME Shafi, A Slaus, I Spinka, H Stanislaus, S Starostin, A Staudenmaier, HM Supek, I Wong, CW TI Search for the CP forbidden decay eta -> 4 pi(0) SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHYSICS AB We report the first determination of the upper limit for the branching ratio of the CP forbidden decay eta --> 4 pi(0). No events were observed in a sample of 3.0 X 10(7) eta decays. The experiment was performed with the Crystal Ball multiphoton spectrometer installed in a separated pi(-) beam at the AGS (Alternating Gradient Synchrotron). At the 90% confidence limit, B(eta --> 4 pi(0)) less than or equal to 6.9 X 10(-7). C1 Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Abilene Christian Univ, Abilene, TX 79699 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Arizona State Univ, Tempe, AZ 85287 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Colorado, Boulder, CO 80309 USA. George Washington Univ, Washington, DC 20052 USA. Univ Karlsruhe, D-76128 Karlsruhe, Germany. Kent State Univ, Kent, OH 44242 USA. Univ Maryland, College Pk, MD 20742 USA. Petersburg Nucl Phys Inst, Gatchina 188350, Leningrad Distr, Russia. Univ Regina, Regina, SK S4S 0A2, Canada. Rudjer Boskovic Inst, Zagreb 10000, Croatia. Valparaiso Univ, Valparaiso, IN 46383 USA. RP Prakhov, S (reprint author), Univ Calif Los Angeles, Los Angeles, CA 90095 USA. OI Papandreou, Zisis/0000-0002-5592-8135 NR 6 TC 24 Z9 24 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 22 PY 2000 VL 84 IS 21 BP 4802 EP 4805 DI 10.1103/PhysRevLett.84.4802 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400005 ER PT J AU Dunn, J Li, Y Osterheld, AL Nilsen, J Hunter, JR Shlyaptsev, VN AF Dunn, J Li, Y Osterheld, AL Nilsen, J Hunter, JR Shlyaptsev, VN TI Gain saturation regime for laser-driven tabletop, transient Ni-like ion x-ray lasers SO PHYSICAL REVIEW LETTERS LA English DT Article ID NM; OPERATION AB We have demonstrated small signal gain saturation on several transient-gain Ni-like ion x-ray lasers by using a high-power, chirped-pulse amplification, tabletop laser. These results have been achieved at wavelengths from 139-203 Angstrom using a total of 5-7 J energy in a traveling-wave excitation scheme. Strong amplification is also observed fur Ni-like Sn at 119 Angstrom. Gain of 62 cm(-1) and gL product of 18 are determined on the 4d --> 4p transition for Ni-like Pd at 147 Angstrom with an output energy of 12 mu J. A systematic evaluation of the laser driver parameters yields optimum beam divergence and small deflection angles of 2-5 mrads, in good agreement with simulations. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Inst Laser Sci & Applicat, Livermore, CA 94550 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94550 USA. RP Li, Y (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. OI Li, Yuelin/0000-0002-6229-7490 NR 23 TC 208 Z9 211 U1 1 U2 3 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 22 PY 2000 VL 84 IS 21 BP 4834 EP 4837 DI 10.1103/PhysRevLett.84.4834 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400013 ER PT J AU Diamond, PH Rosenbluth, MN Sanchez, E Hidalgo, C Van Milligen, B Estrada, T Branas, B Hirsch, M Hartfuss, HJ Carreras, BA AF Diamond, PH Rosenbluth, MN Sanchez, E Hidalgo, C Van Milligen, B Estrada, T Branas, B Hirsch, M Hartfuss, HJ Carreras, BA TI In search of the elusive zonal flow using cross-bicoherence analysis SO PHYSICAL REVIEW LETTERS LA English DT Article ID VELOCITY-SHEAR; TURBULENT TRANSPORT; PLASMA TURBULENCE; TOKAMAK PLASMAS; EDGE TURBULENCE; FLUCTUATIONS; SIMULATIONS; LAYER AB We show that the modulational instability growth rate of zonal flows is determined directly from the quasilinear wave kinetic equation. We also demonstrate the relation between zonal-now growth and the cross bispectrum of the high-frequency drift-wave-driven Reynolds stress and the low-frequency plasma potential by explicit calculation. Experimental measurements of the spatiotemporal evolution of the spectrum integrated bicoherence at the L --> H transition near the edge shear layer indicate a modification in the nonlinear phase coupling, which might be linked to the generation of sheared E X B flows. C1 Univ Calif San Diego, La Jolla, CA 92093 USA. EURATOM, IPP, Madrid 85748, Spain. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. RP Diamond, PH (reprint author), Univ Calif San Diego, La Jolla, CA 92093 USA. RI Sanchez, Edilberto/D-4620-2009; van Milligen, Boudewijn/H-5121-2015; Estrada, Teresa/N-9048-2016; Hidalgo, Carlos/H-6109-2015 OI Sanchez, Edilberto/0000-0003-1062-7870; van Milligen, Boudewijn/0000-0001-5344-6274; Estrada, Teresa/0000-0001-6205-2656; NR 25 TC 114 Z9 114 U1 3 U2 12 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 MAY 22 PY 2000 VL 84 IS 21 BP 4842 EP 4845 DI 10.1103/PhysRevLett.84.4842 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400015 ER PT J AU Chernyshev, AL Castro Neto, AH Bishop, AR AF Chernyshev, AL Castro Neto, AH Bishop, AR TI Metallic stripe in two dimensions: Stability and spin-charge separation SO PHYSICAL REVIEW LETTERS LA English DT Article ID T-J MODEL; HIGH-TEMPERATURE SUPERCONDUCTIVITY; CRITICAL-POINT SCENARIO; PEROVSKITE SUPERCONDUCTORS; QUANTUM ANTIFERROMAGNETS; DOPED ANTIFERROMAGNETS; C SUPERCONDUCTORS; HUBBARD-MODEL; DENSITY-WAVE; T-J(Z) MODEL AB The problems of charge strips formation, spin-charge separation, and stability of the antiphase domain wall (ADW) associated with a stripe are addressed using an analytical approach to the t-J(T), model. We show that a metallic stripe together with its ADW is the ground state of the problem in the low doping regime. The stripe is described as a system of spinons and magnetically confined holons strongly coupled to the two dimensional spin environment with holon-spin-polaron clementary excitations filling a one-dimensional band. C1 Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Russian Acad Sci, Inst Semicond Phys, Novosibirsk 630090, Russia. RP Chernyshev, AL (reprint author), Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. RI Castro Neto, Antonio/C-8363-2014 OI Castro Neto, Antonio/0000-0003-0613-4010 NR 40 TC 56 Z9 56 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 22 PY 2000 VL 84 IS 21 BP 4922 EP 4925 DI 10.1103/PhysRevLett.84.4922 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400035 ER PT J AU Liu, L Jayanthi, CS Tang, MJ Wu, SY Tombler, TW Zhou, CW Alexseyev, L Kong, J Dai, HJ AF Liu, L Jayanthi, CS Tang, MJ Wu, SY Tombler, TW Zhou, CW Alexseyev, L Kong, J Dai, HJ TI Controllable reversibility of an sp(2) to sp(3) transition of a single wall nanotube under the manipulation of an AFM tip: A nanoscale electromechanical switch? SO PHYSICAL REVIEW LETTERS LA English DT Article ID CARBON NANOTUBES; RESOLVENT-MATRIX; ELECTRONIC-STRUCTURE; TRANSPORT; CLUSTERS; SYSTEMS AB A simulation of the deflection of a single wall nanotube under the manipulation of an atomic force microscope tip revealed the key feature characterizing the deformation at relatively small bending angles to be a reversible transition from sp(2) to sp(3) bonding configurations in the bending region, leading to a 2 orders of magnitude reduction in conductance consistent with our most recent experimental observation. A local analysis elucidating the underlying physics of the findings is also discussed. C1 Univ Louisville, Dept Phys, Louisville, KY 40292 USA. Univ Calif Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA 94551 USA. Stanford Univ, Dept Chem, Stanford, CA 94305 USA. RP Liu, L (reprint author), Univ Louisville, Dept Phys, Louisville, KY 40292 USA. RI Zhou, Chongwu/F-7483-2010 NR 18 TC 83 Z9 84 U1 2 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 22 PY 2000 VL 84 IS 21 BP 4950 EP 4953 DI 10.1103/PhysRevLett.84.4950 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400042 ER PT J AU Smith, AW Jaeger, HM Rosenbaum, TF Petrean, AM Kwok, WK Crabtree, GW AF Smith, AW Jaeger, HM Rosenbaum, TF Petrean, AM Kwok, WK Crabtree, GW TI Vortex flow and transverse flux screening at the Bose glass transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID YBA2CU3O7 SINGLE-CRYSTALS; COLUMNAR DEFECTS; UNTWINNED YBA2CU3O7-DELTA; DISORDERED-SYSTEMS; MATCHING FIELD; SUPERCONDUCTORS; TEMPERATURES; LOCALIZATION; DISSIPATION; DYNAMICS AB We study the vortex phase diagram in untwinned YBCO crystals with colunmar defects. These randomly distributed defects are expected to induce a "Bose glass" phase of localized vortices exhibiting a vanishing resistance and Meissner effect for magnetic fields H-perpendicular to transverse to the columns. We directly observe the transverse Meissner effect using a Hall probe array. As predicted, the Meissner state breaks down at temperatures T-x that decrease linearly as H-perpendicular to increases. However, T-s lies far below the conventional melting temperature T-m determined by a vanishing resistivity, suggesting a regime where vortices are effectively localized even when rotated off the columnar defects. C1 Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Smith, AW (reprint author), Univ Chicago, James Franck Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 28 TC 13 Z9 14 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 MAY 22 PY 2000 VL 84 IS 21 BP 4974 EP 4977 DI 10.1103/PhysRevLett.84.4974 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400048 ER PT J AU Norgaard, K Eskildsen, MR Andersen, NH Jensen, J Hedegard, P Klausen, SN Canfield, PC AF Norgaard, K Eskildsen, MR Andersen, NH Jensen, J Hedegard, P Klausen, SN Canfield, PC TI Interdependence of magnetism and superconductivity in the borocarbide TmNi2B2C SO PHYSICAL REVIEW LETTERS LA English DT Article ID CRYSTAL; LUNI2B2C; YNI2B2C; ER; TM AB We have discovered anew antiferromagnetic phase in TmNi2B2C by neutron diffraction. The ordering vector is Q(A) = (0.48,0,0) and the phase appears shove a critical in-plans magnetic field of 0.9 T. The field was applied in order to test the assumption that the zero-field magnetic structure at Q(F) = (0.094, 0.094, 0) would change into a c-axis ferromagnet if superconductivity were destroyed. We present theoretical calculations which show that two effects are important a suppression of the ferromagnetic component of the RKKY exchange interaction in the superconducting phase and a reduction of the superconducting condensation energy due to the periodic modulation of the moments at Q(A). C1 Riso Natl Lab, Condensed Matter Phys & Chem Dept, DK-4000 Roskilde, Denmark. Niels Bohr Inst, Orsted Lab, fAPG, DK-2100 Copenhagen, Denmark. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. RP Norgaard, K (reprint author), Riso Natl Lab, Condensed Matter Phys & Chem Dept, DK-4000 Roskilde, Denmark. RI Eskildsen, Morten/E-7779-2011; Andersen, Niels/A-3872-2012; Canfield, Paul/H-2698-2014; Jensen, Jens/C-7484-2015; Hedegard, Per/C-1954-2015 OI Jensen, Jens/0000-0002-7954-8073; Hedegard, Per/0000-0002-6328-7462 NR 20 TC 31 Z9 31 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 22 PY 2000 VL 84 IS 21 BP 4982 EP 4985 DI 10.1103/PhysRevLett.84.4982 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400050 ER PT J AU Hegger, H Petrovic, C Moshopoulou, EG Hundley, MF Sarrao, JL Fisk, Z Thompson, JD AF Hegger, H Petrovic, C Moshopoulou, EG Hundley, MF Sarrao, JL Fisk, Z Thompson, JD TI Pressure-induced superconductivity in quasi-2D CeRhIn5 SO PHYSICAL REVIEW LETTERS LA English DT Article ID TEMPERATURE; PARAMETER; ELECTRON; SYSTEMS; METALS; STATES; MODEL AB CrRhIn5 is a new heavy-electron material that crystallizes in a quasi-2D structure that can be viewed as alternating layers of CeIn3 and RhIn2 stacked sequentially along the tetragonal c axis. Application of hydrostatic pressure induces a first-order-like transition from an unconventional antoferromagnetic state to a superconducting state with T-c = 2.1 K. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Florida State Univ, NHMFL, Tallahassee, FL 32306 USA. RP Hegger, H (reprint author), Bayer AG, IM, EMS, CAE1, D-5090 Leverkusen, Germany. RI Petrovic, Cedomir/A-8789-2009 OI Petrovic, Cedomir/0000-0001-6063-1881 NR 21 TC 682 Z9 684 U1 8 U2 78 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 MAY 22 PY 2000 VL 84 IS 21 BP 4986 EP 4989 DI 10.1103/PhysRevLett.84.4986 PG 4 WC Physics, Multidisciplinary SC Physics GA 315LC UT WOS:000087114400051 ER PT J AU Semak, VV Steele, RJ Fuerschbach, PW Damkroger, BK AF Semak, VV Steele, RJ Fuerschbach, PW Damkroger, BK TI Role of beam absorption in plasma during laser welding SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article ID KEYHOLE; PENETRATION; MODEL; BALANCE AB The relationship between beam focus position and penetration depth in CW laser welding was studied numerically and experimentally for different welding conditions. Calculations were performed using a transient hydrodynamic model that incorporates the effect of evaporation recoil pressure and the associated melt expulsion. The simulation results are compared with measurements made on a series of test welds obtained using a 1650 W COL laser. Thr simulations predict, and the experiments confirm, that maximum penetration occurs with a specific location of the beam focus, with respect to the original sample surface, and that this relationship depends on the processing conditions. In particular, beam absorption in the plasma has a significant effect on the relationship between penetration and focus position, When the process parameters result in strong beam absorption in the keyhole plasma, the maximum penetration will occur when the laser focus is at or above the sample surface. In a case of weak absorption however, the penetration depth reaches its maximum value when the beam focus is located below the sample surface. In all cases, the numerical results are in good agreement with the experimental measurements. C1 New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. USN, Air Warfare Ctr, China Lake, CA 93555 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Semak, VV (reprint author), New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. NR 18 TC 19 Z9 24 U1 3 U2 12 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD MAY 21 PY 2000 VL 33 IS 10 BP 1179 EP 1185 DI 10.1088/0022-3727/33/10/307 PG 7 WC Physics, Applied SC Physics GA 320HT UT WOS:000087396300008 ER PT J AU Atwood, WB Ritz, S Anthony, P Bloom, ED Bosted, PE Bourotte, J Chaput, C Chen, X Chenette, DL Engovatov, D Erickson, R Fieguth, T Fleury, P Gearhart, R Godfrey, G Grove, JE Hernando, JA Hirayama, M Jaggar, S Johnson, RP Johnson, WN Jones, BB Kroger, W Lin, YC Meetre, C Michelson, PF Milne, PA Moiseev, A Nolan, P Norris, JP Oreglia, M Ormes, JF Phlips, BF Pocar, A Sadrozinski, HFW Szalata, Z Thompson, DJ Tompkins, WF AF Atwood, WB Ritz, S Anthony, P Bloom, ED Bosted, PE Bourotte, J Chaput, C Chen, X Chenette, DL Engovatov, D Erickson, R Fieguth, T Fleury, P Gearhart, R Godfrey, G Grove, JE Hernando, JA Hirayama, M Jaggar, S Johnson, RP Johnson, WN Jones, BB Kroger, W Lin, YC Meetre, C Michelson, PF Milne, PA Moiseev, A Nolan, P Norris, JP Oreglia, M Ormes, JF Phlips, BF Pocar, A Sadrozinski, HFW Szalata, Z Thompson, DJ Tompkins, WF TI Beam test of gamma-ray large area space telescope components SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article ID DETECTOR; GLAST AB A beam test of Gamma-ray Large Area Space Telescope (GLAST) components was performed at the Stanford Linear Accelerator Center in October 1997. These beam test components were simple versions of the planned flight hardware. Results on the performance of the tracker, calorimeter, and anti-coincidence charged particle veto are presented. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. American Univ, Washington, DC 20016 USA. Ecole Polytech, Palaiseau, France. Columbia Univ, New York, NY 10027 USA. Lockheed Martin, Palo Alto, CA USA. USN, Res Lab, Washington, DC 20375 USA. Stanford Univ, Stanford, CA 94305 USA. Clemson Univ, Clemson, SC USA. Univ Space Res Assoc, Washington, DC USA. Univ Chicago, Chicago, IL 60637 USA. RP Ritz, S (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Nolan, Patrick/A-5582-2009; Thompson, David/D-2939-2012; Johnson, Neil/G-3309-2014; Hernando Morata, Jose Angel/L-7642-2014 OI Thompson, David/0000-0001-5217-9135; Hernando Morata, Jose Angel/0000-0002-8683-5142 NR 18 TC 26 Z9 26 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 2000 VL 446 IS 3 BP 444 EP 460 DI 10.1016/S0168-9002(99)00980-8 PG 17 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 318YP UT WOS:000087312500004 ER PT J AU Ludington, MA Helmer, RG AF Ludington, MA Helmer, RG TI High accuracy measurements and Monte Carlo calculations of the relative efficiency curve of an HPGe detector from 433 to 2754 keV SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE efficiency calibration; gamma rays; Monte Carlo; high-purity germanium detection system; Ge detectors AB The relative full-energy peak efficiency curve of a 280-cm(3) coaxial HPGe detector was determined to an accuracy of about 0.1% over the energy range from 433 to 2754 keV from pairs of gamma-ray lines whose emission probabilities are very accurately known. The curve was extended from previous studies by the addition of lines from (108)mAg and Na-24. Ratios of full- energy peak efficiencies were also determined by Monte Carlo calculations using the CYLTRAN code. The measured ratios and the Monte Carlo values were in excellent agreement (0.03-0.19 %). The relative efficiency was defined by a pair of functions, one for 433-1332 and one for 614-2754 keV. Monte Carlo values were used to supplement the measured values, resulting in a more accurate fit. The stability of the relative efficiency curve for a 94-cm(3) HPGe detector was studied and it was found that there was no statistically significant change over a period of 3 years. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Albion Coll, Dept Phys, Albion, MI 49224 USA. Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Ludington, MA (reprint author), Albion Coll, Dept Phys, Albion, MI 49224 USA. NR 12 TC 32 Z9 32 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 2000 VL 446 IS 3 BP 506 EP 521 DI 10.1016/S0168-9002(99)01253-X PG 16 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 318YP UT WOS:000087312500009 ER PT J AU Wong, J Waide, PA Elmer, JW Thompson, AC AF Wong, J Waide, PA Elmer, JW Thompson, AC TI Spatially resolved diffraction using a Seller Collimator-Imaging plate assembly SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE synchrotron radiation instrumentation; spatially resolved diffraction; soller collimator; imaging plates ID X-RAY-DIFFRACTION; HEAT-AFFECTED ZONE; SYNCHROTRON-RADIATION; FUSION WELDS; PHASE; TRANSFORMATION; DIFFRACTOMETER; DETECTOR AB A series of multiple foil collimators have been constructed to perform spatially resolved diffraction using a synchrotron radiation X-ray source and a two-dimensional X-ray detector. Slit gap sizes of 0.75, 0.25 and 0.125 mm were evaluated. A thin vanadium foil (BCC) on bulk titanium (HCP) was studied as a test system. This system simulates an alpha-Ti (HCP) -> beta-Ti (BCC) transformation in the heat affected zone of Ti fusion welds. Diffraction lines from both V(2 0 0) and Ti(1 0 2) were measured in the gap aligned with the V/Ti boundary. With improvements in the mounting of the slits, a spatial resolution of at least 0.12 mm will be possible. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Wong, J (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808, Livermore, CA 94551 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 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 21 PY 2000 VL 446 IS 3 BP 581 EP 591 DI 10.1016/S0168-9002(99)01175-4 PG 11 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 318YP UT WOS:000087312500016 ER PT J AU Chow, E AF Chow, E TI A priori sparsity patterns for parallel sparse approximate inverse preconditioners SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 5th Copper Mountain Meeting on Iterative Methods CY APR, 1998 CL COPPER MOUNTAIN, ALASKA DE preconditioned iterative methods; sparse approximate inverses; graph theory; parallel computing ID DENSE LINEAR-SYSTEMS; MATRICES AB Parallel algorithms for computing sparse approximations to the inverse of a sparse matrix either use a prescribed sparsity pattern for the approximate inverse or attempt to generate a good pattern as part of the algorithm. This paper demonstrates that, for PDE problems, the patterns of powers of sparsified matrices (PSMs) can be used a priori as effective approximate inverse patterns, and that the additional effort of adaptive sparsity pattern calculations may not be required. PSM patterns are related to various other approximate inverse sparsity patterns through matrix graph theory and heuristics concerning the PDE's Green's function. A parallel implementation shows that PSM-patterned approximate inverses are significantly faster to construct than approximate inverses constructed adaptively, while often giving preconditioners of comparable quality. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. RP Chow, E (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, L-560,Box 808, Livermore, CA 94551 USA. NR 32 TC 103 Z9 105 U1 1 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 2000 VL 21 IS 5 BP 1804 EP 1822 DI 10.1137/S106482759833913X PG 19 WC Mathematics, Applied SC Mathematics GA 319BX UT WOS:000087320700011 ER PT J AU Brown, PN Falgout, RD Jones, JE AF Brown, PN Falgout, RD Jones, JE TI Semicoarsening multigrid on distributed memory machines SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 5th Copper Mountain Meeting on Iterative Methods CY APR, 1998 CL COPPER MOUNTAIN, ALASKA DE parallel multigrid methods; diffusion equations; scalability studies ID ALGORITHM; SOLVERS AB This paper presents the results of a scalability study for a three-dimensional semi-coarsening multigrid solver on a distributed memory computer. In particular, we are interested in the scalability of the solver how the solution time varies as both problem size and number of processors are increased. For an iterative linear solver, scalability involves both algorithmic issues and implementation issues. We examine the scalability of the solver theoretically by constructing a simple parallel model and experimentally by results obtained on an IBM SP. The results are compared with those obtained for other solvers on the same computer. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. RP Brown, PN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, L-561, Livermore, CA 94550 USA. OI Jones, Jim/0000-0002-0144-6130 NR 12 TC 50 Z9 52 U1 0 U2 1 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 2000 VL 21 IS 5 BP 1823 EP 1834 DI 10.1137/S1064827598339141 PG 12 WC Mathematics, Applied SC Mathematics GA 319BX UT WOS:000087320700012 ER PT J AU Benzi, M Tuma, M AF Benzi, M Tuma, M TI Orderings for factorized sparse approximate inverse preconditioners SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 5th Copper Mountain Meeting on Iterative Methods CY APR, 1998 CL COPPER MOUNTAIN, ALASKA DE sparse linear systems; sparse matrices; preconditioned Krylov subspace methods; graph theory; orderings; decay rates; factorized sparse approximate inverses; incomplete biconjugation ID LINEAR-SYSTEMS; BAND MATRICES; DECAY-RATES; ELIMINATION AB The influence of reorderings on the performance of factorized sparse approximate inverse preconditioners is considered. Some theoretical results on the effect of orderings on the fill-in and decay behavior of the inverse factors of a sparse matrix are presented. It is shown experimentally that certain reorderings, like minimum degree and nested dissection, can be very beneficial. The benefit consists of a reduction in the storage and time required for constructing the preconditioner, and of faster convergence of the preconditioned iteration in many cases of practical interest. C1 Univ Calif Los Alamos Natl Lab, Sci Comp Grp CIC 19, Los Alamos, NM 87545 USA. Acad Sci Czech Republ, Inst Comp Sci, Prague 18207 8, Czech Republic. RP Benzi, M (reprint author), Univ Calif Los Alamos Natl Lab, Sci Comp Grp CIC 19, MS B256, Los Alamos, NM 87545 USA. RI Tuma, Miroslav/A-5946-2014 OI Tuma, Miroslav/0000-0003-2808-6929 NR 38 TC 47 Z9 50 U1 1 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 2000 VL 21 IS 5 BP 1851 EP 1868 DI 10.1137/S1064827598339372 PG 18 WC Mathematics, Applied SC Mathematics GA 319BX UT WOS:000087320700014 ER PT J AU Cleary, AJ Falgout, RD Henson, VE Jones, JE Manteuffel, TA McCormick, SF Miranda, GN Ruge, JW AF Cleary, AJ Falgout, RD Henson, VE Jones, JE Manteuffel, TA McCormick, SF Miranda, GN Ruge, JW TI Robustness and scalability of algebraic multigrid SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 5th Copper Mountain Meeting on Iterative Methods CY APR, 1998 CL COPPER MOUNTAIN, AK DE algebraic multigrid; interpolation; unstructured meshes; scalability ID ELLIPTIC PROBLEMS; INTERPOLATION; 2ND-ORDER AB Algebraic multigrid (AMG) is currently undergoing a resurgence in popularity, due in part to the dramatic increase in the need to solve physical problems posed on very large, unstructured grids. While AMG has proved its usefulness on various problem types, it is not commonly understood how wide a range of applicability the method has. In this study, we demonstrate that range of applicability, while describing some of the recent advances in AMG technology. Moreover, in light of the imperatives of modern computer environments, we also examine AMG in terms of algorithmic scalability. Finally, we show some of the situations in which standard AMG does not work well and indicate the current directions taken by AMG researchers to alleviate these difficulties. C1 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. Univ Colorado, Dept Appl Math, Boulder, CO 80309 USA. USS Florida SSBM 728, Silverdale, WA 98315 USA. Front Range Sci, Boulder, CO 80303 USA. RP Cleary, AJ (reprint author), Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94550 USA. EM cleary@llnl.gov; rfalgout@llnl.gov; vhenson@llnl.gov; jjones@llnl.gov; tmanteuf@boulder.colorado.edu; stevem@boulder.colorado.edu; JerryTrish@aol.com; jruge@sobolev.colorado.edu OI Jones, Jim/0000-0002-0144-6130 NR 36 TC 77 Z9 80 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 2000 VL 21 IS 5 BP 1886 EP 1908 DI 10.1137/S1064827598339402 PG 23 WC Mathematics, Applied SC Mathematics GA 319BX UT WOS:000087320700016 ER PT J AU Lee, B Manteuffel, TA McCormick, SF Ruge, J AF Lee, B Manteuffel, TA McCormick, SF Ruge, J TI First-order system least-squares for the Helmholtz equation SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 5th Copper Mountain Meeting on Iterative Methods CY APR, 1998 CL COPPER MOUNTAIN, ALASKA DE first-order system least-squares; Helmholtz equation; nonstandard multigrid ID FIELDS AB This paper develops a multilevel least-squares approach for the numerical solution of the complex scalar exterior Helmholtz equation. This second-order equation is rst recast into an equivalent first-order system by introducing several field variables. A combination of scaled L-2 and H-1 norms is then applied to the residual of this system to create a least-squares functional. It is shown that, in an appropriate Hilbert space, the homogeneous part of this functional is equivalent to a squared graph norm, that is, a product norm on the space of individual variables. This equivalence to a norm that decouples the variables means that standard finite element discretization techniques and standard multigrid solvers can be applied to obtain optimal performance. However, this equivalence is not uniform in the wavenumber k, which can signal degrading performance of the numerical solution process as k increases. To counter this difficulty, we obtain a result that characterizes the error components causing performance degradation. We do this by defining a finite-dimensional subspace of these components on whose orthogonal complement k-uniform equivalence is proved for this functional and an analogous functional that is based only on L-2 norms. This subspace equivalence motivates a nonstandard multigrid method that attempts to achieve optimal convergence uniformly in k. We report on numerical experiments that empirically confirm k-uniform optimal performance of this multigrid solver. We also report on tests of the error in our discretization that seem to con rm optimal accuracy that is free of the so-called pollution effect. C1 Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. Univ Colorado, Dept Appl Math, Boulder, CO 80309 USA. RP Lee, B (reprint author), Univ Calif Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, POB 808,L-661, Livermore, CA 94551 USA. NR 28 TC 37 Z9 37 U1 0 U2 2 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 2000 VL 21 IS 5 BP 1927 EP 1949 DI 10.1137/S1064827598339773 PG 23 WC Mathematics, Applied SC Mathematics GA 319BX UT WOS:000087320700018 ER PT J AU Lackner, K Menikoff, R AF Lackner, K Menikoff, R TI Multiscale linear solvers for very large systems derived from PDEs SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article; Proceedings Paper CT 5th Copper Mountain Meeting on Iterative Methods CY APR, 1998 CL COPPER MOUNTAIN, ALASKA DE multigrid; conjugate gradient; linear solver; porous flow ID CONJUGATE-GRADIENT METHOD; ELLIPTIC PROBLEMS AB We present a novel linear solver that works well for large systems obtained from discretizing PDEs. It is robust and, for the examples we studied, the computational effort scales linearly with the number of equations. The algorithm is based on a wavelength decomposition that combines conjugate gradient, multiscaling, and iterative splitting methods into a single approach. On the surface, the algorithm is a simple preconditioned conjugate gradient with all the sophistication of the algorithm in the choice of the preconditioning matrix. The preconditioner is a very good approximate inverse of the linear operator. It is constructed from the inverse of the coarse grained linear operator and from smoothing operators that are based on an operator splitting on the ne grid. The coarse graining captures the long wavelength behavior of the inverse operator, while the smoothing operator captures the short wavelength behavior. The conjugate gradient iteration accounts for the coupling between long and short wavelengths. The coarse grained operator corresponds to a lower resolution approximation to the PDEs. While the coarse grained inverse is not known explicitly, the algorithm requires only that the preconditioner can be a applied to a vector. The coarse inverse applied to a vector can be obtained as the solution of another preconditioned conjugate gradient solver that applies the same algorithm to the smaller problem. Thus, the method is naturally recursive. The recursion ends when the matrix is sufficiently small for a solution to be obtained efficiently with a standard solver. The local feedback provided by the conjugate gradient step at every level makes the algorithm very robust. In spite of the effort required for the coarse inverse, the algorithm is efficient because the increased quality of the approximate inverse greatly reduces the number of times the preconditioner needs to be evaluated. A feature of the algorithm is that the transition between coarse grids is determined dynamically by the accuracy requirement of the conjugate gradient solver at each level. Typically, later iterations on the ner scales need fewer iterations on the coarser scales and the computational effort is proportional to N rather than N log N, where N is the number of equations. We have tested our solver on the porous ow equation. On a workstation we have solved problems on grids ranging in dimension over three orders of magnitude, from 10(3) to 10(6), and found that the linear scaling holds. The algorithm works well, even when the permeability tensor has spatial variations exceeding a factor of 10(9). C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Lackner, K (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Mail Stop B-216, Los Alamos, NM 87545 USA. NR 11 TC 1 Z9 1 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 2000 VL 21 IS 5 BP 1950 EP 1968 DI 10.1137/S1064827598339785 PG 19 WC Mathematics, Applied SC Mathematics GA 319BX UT WOS:000087320700019 ER PT J AU Spuler, S Linne, M Sappey, A Snyder, S AF Spuler, S Linne, M Sappey, A Snyder, S TI Development of a cavity ringdown laser absorption spectrometer for detection of trace levels of mercury SO APPLIED OPTICS LA English DT Article ID SPECTROSCOPY; LIDAR; AIR AB A potential new laser-based air pollution measurement technique, capable of measuring ultralow concentrations of urban air toxins in the held and in real time, is examined. Cavity ringdown laser absorption spectroscopy (CRLAS) holds promise as an air pollution monitor because it is a highly sensitive species detection technique that uses either pulsed or continuous tunable laser sources. The sensitivity results from an extremely long absorption path length and the fact that the quantity measured, the cavity decay time, is unaffected by fluctuations in the laser source. In laboratory experiments, we reach detection limits for mercury of the order of 0.50 parts per trillion. We developed a CRLAS system in our laboratory and measured Hg with the system, investigating issues such as background interference. We report experimental results for mercury detection limits, the dynamic range of the sensor, detection of Hg in an absorbing background of ozone and SO2, and detection of a mercury-containing compound (HgCl2 in this case). (C) 2000 Optical Society of America OCIS codes: 010.1120, 120.4640, 120.6200, 230.0230, 300.1030, 300.6540. C1 Colorado Sch Mines, Dept Engn, Golden, CO 80401 USA. ADA Technol, Englewood, CO 80112 USA. Idaho Natl Lab, Idaho Falls, ID 83415 USA. RP Spuler, S (reprint author), Colorado Sch Mines, Dept Engn, Golden, CO 80401 USA. EM sspuler@mines.edu NR 19 TC 34 Z9 34 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 2000 VL 39 IS 15 BP 2480 EP 2486 DI 10.1364/AO.39.002480 PG 7 WC Optics SC Optics GA 315NQ UT WOS:000087120200017 PM 18345163 ER PT J AU Paerels, F Kuulkers, E Heise, J Liedahl, DA AF Paerels, F Kuulkers, E Heise, J Liedahl, DA TI X-ray spectral diagnostics of gamma-ray burst environments SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; line : formation; techniques : spectroscopic; X-rays : general ID IRON LINE; AFTERGLOW; EMISSION; CYGNUS-X-3; GRB-970508; PLASMA AB Recently, detection of discrete features in the X-ray afterglow spectra of GRB 970508 and GRB 970828 was reported. The most natural interpretation of these features is that they are redshifted Fe K emission complexes. The identification of the line emission mechanism has drastic implications for the inferred mass of radiating material and hence the nature of the burst site. X-ray spectroscopy provides a direct observational constraint on these properties of gamma-ray bursters. We briefly discuss how these constraints arise in the context of an application to the spectrum of GRB 970508. C1 SRON, Space Res Lab, NL-3584 CA Utrecht, Netherlands. Univ Calif Lawrence Livermore Natl Lab, Dept Phys & Space Technol, Livermore, CA 94550 USA. RP Paerels, F (reprint author), Columbia Univ, Astrophys Lab, 538 W 120th St, New York, NY 10027 USA. NR 24 TC 13 Z9 14 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2000 VL 535 IS 1 BP L25 EP L28 DI 10.1086/312699 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 325EA UT WOS:000087662300007 ER PT J AU Wu, BB Fenimore, E AF Wu, BB Fenimore, E TI Spectral lags of gamma-ray bursts from Ginga and BATSE SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID ENERGY; EVOLUTION; DURATION AB The analysis of spectral lag between energy bands, which combines temporal and spectral analyses, can add strict constraints to gamma-ray burst (GRB) models. In previous studies, the lag analysis focused on the lags between channel 1 (25-57 keV) and channel 3 (115-320 keV) from the Burst and Transient Source Experiment (BATSE). In this Letter, we analyzed the cross-correlation average lags (including approximate uncertainties) between energy bands for two GRB samples: 19 events detected by Ginga and 109 events detected by BATSE. We paid special attention to the BATSE GRBs with known redshifts because there has been a reported connection between lag and luminosity. This extends our knowledge of spectral lags to lower energy (similar to 2 keV). We found that lags between energy bands are small. The lag between the peak of similar to 50 keV photons and that of similar to 200 keV photons is similar to 0.08 s. The upper limit in the lag between similar to 9 and similar to 90 keV photons is similar to 0.5 s. Thus, there are not large shifts at low energy. We found that about 20% of GRBs have detectable lags between energy bands in the Ginga and BATSE samples. From the internal shock model, we found that there are three sources of time structure in GRB pulses: cooling, hydrodynamics, and angular effects. We argue that cooling is much too fast to account for our observed lags and that angular effects are independent of energy. Thus, only hydrodynamics can produce these lags. Perhaps the radiation process varies as the reverse shock moves through the shell. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Chinese Acad Sci, Inst High Energy Phys, Cosm Ray & High Energy Astrophys Lab, Beijing 100039, Peoples R China. RP Wu, BB (reprint author), Univ Calif Los Alamos Natl Lab, MS D436, Los Alamos, NM 87545 USA. NR 17 TC 35 Z9 37 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 20 PY 2000 VL 535 IS 1 BP L29 EP L32 DI 10.1086/312700 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 325EA UT WOS:000087662300008 ER PT J AU Mousseau, VA Knoll, DA Rider, WJ AF Mousseau, VA Knoll, DA Rider, WJ TI Physics-based preconditioning and the Newton-Krylov method for non-equilibrium radiation diffusion SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE Jacobian-free Newton Krylov; radiation diffusion; multigrid ID SYSTEMS AB An algorithm is presented for the solution of the time dependent reaction-diffusion systems which arise in non-equilibrium radiation diffusion applications. This system of nonlinear equations is solved by coupling three numerical methods, Jacobian-free Newton-Krylov, operator splitting, and multigrid linear solvers. An inexact Newton's method is used to solve the system of nonlinear equations. Since building the Jacobian matrix for problems of interest can be challenging, we employ a Jacobian-free implementation of Newton's method, where the action of the Jacobian matrix on a vector is approximated by a first order Taylor series expansion. Preconditioned generalized minimal residual (PGMRES) is the Krylov method used to solve the Linear systems that come from the iterations of Newton's method. The preconditioner in this solution method is constructed using a physics-based divide and conquer approach, often referred to as operator splitting. This solution procedure inverts the scalar elliptic systems that make up the preconditioner using simple multigrid methods. The preconditioner also addresses the strong coupling between equations with local 2 x 2 block solves, The intra-cell coupling is applied after the inter-cell coupling has already been addressed by the elliptic solves. Results are presented using this solution procedure that demonstrate its efficiency while incurring minimal memory requirements. (C) 2000 Academic Press. C1 Univ Calif Los Alamos Natl Lab, D413, Los Alamos, NM 87545 USA. RP Mousseau, VA (reprint author), Univ Calif Los Alamos Natl Lab, D413, POB 1663, Los Alamos, NM 87545 USA. NR 25 TC 77 Z9 83 U1 1 U2 4 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD MAY 20 PY 2000 VL 160 IS 2 BP 743 EP 765 DI 10.1006/jcph.2000.6488 PG 23 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 315BR UT WOS:000087093200018 ER PT J AU Jeong, MS Frei, H AF Jeong, MS Frei, H TI Acetaldehyde as a probe for the chemical properties of aluminophosphate molecular sieves. An in situ FT-IR study SO JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL LA English DT Article DE aluminophosphate molecular sieve; transition metals; infrared spectroscopy; acetaldehyde; Lewis acid sites ID PARAMAGNETIC DEFECT CENTERS; REDOX CENTERS; ACID SITES; ZEOLITES; ACETONE; ADSORPTION; CATALYSTS; COBALT; CONDENSATION; SPECTROSCOPY AB Loading of acetaldehyde from the gas phase into transition metal substituted aluminophosphate sieves of AFI structure resulted in mainly physisorbed CH3CH=O in the case of FeAlPO4-5. By contrast, FT-IR spectroscopy revealed extensive chemical reaction upon loading into metal-free AlPO4-5 and CoAlPO4-5 materials at temperatures as low as - 100 degrees C. The low temperature product is identified as acetaldol, which dehydrates to crotonaldehyde upon warm-up to room temperature. The reactive sites are proposed to be Lewis acid sites in the aluminophosphate framework. Using FT-IR monitoring of acetaldehyde in the pores of aluminophosphate sieves as a sensitive method for the detection of Lewis acid sites, we find that their abundance varies substantially with metal substitution. Interestingly, isomorphous Fe substitution of the aluminophosphate framework seems to suppress the formation of such defect sites. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Calvin Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Frei, H (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Calvin Lab, Phys Biosci Div, Berkeley, CA 94720 USA. NR 36 TC 8 Z9 9 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1169 J9 J MOL CATAL A-CHEM JI J. Mol. Catal. A-Chem. PD MAY 20 PY 2000 VL 156 IS 1-2 BP 245 EP 253 DI 10.1016/S1381-1169(99)00421-5 PG 9 WC Chemistry, Physical SC Chemistry GA 322UC UT WOS:000087526500023 ER PT J AU Selvamanickam, V Galinski, GB Carota, G DeFrank, J Trautwein, C Haldar, P Balachandran, U Chudzik, M Coulter, JY Arendt, PN Groves, JR DePaula, RF Newnam, BE Peterson, DE AF Selvamanickam, V Galinski, GB Carota, G DeFrank, J Trautwein, C Haldar, P Balachandran, U Chudzik, M Coulter, JY Arendt, PN Groves, JR DePaula, RF Newnam, BE Peterson, DE TI High-current Y-Ba-Cu-O superconducting films by metal organic chemical vapor deposition on flexible metal substrates SO PHYSICA C LA English DT Article DE critical current density; thin films; YBCO; MOCVD; IBAD ID YBA2CU3O7-DELTA THICK-FILMS; COATED CONDUCTORS; ANISOTROPY; TAPES AB A metal organic chemical vapor deposition (MOCVD) method has been developed to achieve high currents in Y-Ba-Cu-O (YBCO) superconducting films deposited on biaxially textured buffer layers on polycrystalline (untextured) flexible metal substrates. Optimization of the MOCVD process parameters has yielded critical currents (I-c) greater than 50 A and critical current densities (J(c)) higher than 1 MA/cm(2) at 77 K in self-field conditions. High values of critical currents were found to be maintained also in the presence of a magnetic field. At 75 K, with the magnetic field perpendicular to the c-axis (B perpendicular to c), J(c) values of 570,000 A/cm(2) (I-c = 20 A) and 240,000 A/cm(2) (I-c = 8.5 A) were achieved in fields of 1 and 5 T respectively. With the magnetic field parallel to the c-axis (B parallel to c), J(c) values of 215,000 A/cm(2) (I-c = 7.6 A) and 100,000 A/cm(2) (I-c = 3.6 A) were achieved in fields of 1 and 2.5 T respectively. At 64 K, the J(c) values were 1.2 MA/cm(2) (I-c = 43 A) and 770,000 A/cm(2) (I-c = 27 A) at 2 and 5 T respectively in the B perpendicular to c orientation. In the B parallel to c orientation, the J(c) values were 680,000 A/cm(2) (I-c = 23.7 A), 520,000 A/cm(2) (I-c = 18.2 A) and 300,000 A/cm(2) (I-c = 10.6 A) at 1, 2, and 5 T respectively. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Intermagnet Gen Corp, Latham, NY 12110 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Selvamanickam, V (reprint author), Intermagnet Gen Corp, Latham, NY 12110 USA. NR 18 TC 25 Z9 25 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 20 PY 2000 VL 333 IS 3-4 BP 155 EP 162 DI 10.1016/S0921-4534(00)00231-8 PG 8 WC Physics, Applied SC Physics GA 317UL UT WOS:000087245300004 ER PT J AU Xu, YW Kramer, MJ Dennis, KW Wu, H O'Connor, A McCallum, RW Malik, SK Yelon, WB AF Xu, YW Kramer, MJ Dennis, KW Wu, H O'Connor, A McCallum, RW Malik, SK Yelon, WB TI Substitution for Ba by Pr, La, and Eu in Eu(Ba1-xRx)(2)Cu3O7+delta solid solutions SO PHYSICA C LA English DT Article DE superconductivity; Eu-Pr-La-Ba-Cu-O; neutron diffraction; Rietveld refinement ID X-RAY-ABSORPTION; ELECTRONIC-STRUCTURE; SINGLE-CRYSTALS; SUPERCONDUCTIVITY; TEMPERATURE; ND1+XBA2-XCU3O7+DELTA; SPECTROSCOPY; THERMOPOWER; SUPPRESSION; PRBA2CU3O7 AB We did a detailed study on a series of samples of Eu(Ba1-xRx)(2)Cu3O7+delta (where R = La, Pr and Eu) by X-ray diffraction, neutron diffraction, magnetic and thermopower measurements. All R3+ substitutes went to the Ba2+ site and suppress superconductivity. The suppression of superconductivity does not have a simple relation to the ionic size of the substitutes. On the other hand, the change in crystal structure from orthorhombic to tetragonal has a strong dependence on the ionic size of the substitutes. Pr on Ba site did not cause unexpected structural distortions yet suppress superconductivity at a rate faster than other rare earths. Data of thermopower measurements and neutron diffraction from our rare earth substituted Eu123 samples show that the suppression of superconductivity by Pr on Ba site is electronic, not magnetic in nature. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Minnesota State Univ, Dept Phys & Astron, Mankato, MN 56001 USA. Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. Univ Missouri, Res Reactor, Columbia, MO 65211 USA. RP Xu, YW (reprint author), Minnesota State Univ, Dept Phys & Astron, Mankato, MN 56001 USA. NR 25 TC 21 Z9 21 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 20 PY 2000 VL 333 IS 3-4 BP 195 EP 206 DI 10.1016/S0921-4534(00)00192-1 PG 12 WC Physics, Applied SC Physics GA 317UL UT WOS:000087245300009 ER PT J AU Lao, JY Wang, JH Wang, DZ Tu, Y Yang, SX Wu, HL Ren, ZF Verebelyi, DT Paranthaman, M Aytug, T Christen, DK Bhattacharya, RN Blaugher, RD AF Lao, JY Wang, JH Wang, DZ Tu, Y Yang, SX Wu, HL Ren, ZF Verebelyi, DT Paranthaman, M Aytug, T Christen, DK Bhattacharya, RN Blaugher, RD TI Synthesis and characterization of chromium-containing, thallium-based 1212 films SO PHYSICA C LA English DT Article DE thin films; TlCr-1212 superconductors; high J(c) ID CRITICAL-CURRENT DENSITY; THIN-FILMS; BUFFER LAYERS; SUPERCONDUCTING TAPES; TL0.78BI0.22SR1.6BA0.4CA2CU3O9; TEMPERATURE AB Epitaxial (Tl,Bi)Sr2Cr0.15Ca0.85Cu2Oy [(Tl,Bi)-1212] films have been successfully grown on both LaAlO3 and CeO2/YSZ substrates by post-deposition annealing in flowing argon gas. These superconducting Tl-based, 1212-structured films on LaAlO3 substrates have T-c values in the range of 94-100 K, and J(c) values over 1.0 x 10(6) A/cm(2) at 77 K. The films are predominately 1212 phase, with excellent epitaxy as determined by XRD theta-2 theta, omega and phi scans. The films on CeO2/YSZ substrates have T-c values in the range of 94-96 K, J(c) (77 K) values close to 6 x 10(5) A/cm(2) and excellent epitaxy on the CeO2 buffer layers. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Boston Coll, Dept Phys, Chestnut Hill, MA 02467 USA. SUNY Buffalo, Dept Chem, Buffalo, NY 14260 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Ren, ZF (reprint author), Boston Coll, Dept Phys, 140 Commonwealth Ave, Chestnut Hill, MA 02467 USA. RI Ren, Zhifeng/B-4275-2014; Paranthaman, Mariappan/N-3866-2015 OI Paranthaman, Mariappan/0000-0003-3009-8531 NR 15 TC 9 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 20 PY 2000 VL 333 IS 3-4 BP 221 EP 228 DI 10.1016/S0921-4534(00)00230-6 PG 8 WC Physics, Applied SC Physics GA 317UL UT WOS:000087245300012 ER PT J AU Durmus, P Boyukata, M Ozcelik, S Guvenc, ZB Jellinek, J AF Durmus, P Boyukata, M Ozcelik, S Guvenc, ZB Jellinek, J TI Reactions of small Ni clusters with a diatomic molecule: MD simulation of D(2)+Ni(n) (n=7-10) systems SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 18th European Conference on Surface Science (ECOSS 18) CY SEP 21-24, 1999 CL VIENNA UNIV TECHNOL, VIENNA, AUSTRIA SP Inst Allgemeine Phys HO VIENNA UNIV TECHNOL DE chemisorption; clusters; computer simulations; molecular dynamics; nickel; semi-empirical models and model calculations ID NI(111) SURFACES; NICKEL CLUSTERS; H-2; DYNAMICS; HYDROGEN; DISSOCIATION; REACTIVITY; DEUTERIUM; NI(100); D2 AB The kinetics of the reactions of nickel clusters with a deuterium molecule are studied, Dissociative chemisorption probabilities of the D(2) molecule on the small Ni(n) (n=7-10) clusters are computed by a quasi-classical molecular dynamics computer simulation technique. Structures of the clusters are obtained by an embedded-atom potential, and the interaction between the D(2) and Ni(n) is modelled by an LEPS (London-Eyring-Polanyi-Sato) function (energy surface). This analysis includes the chemisorption probabilities as functions of the impact parameter and of the relative translational energy of the D(2). The corresponding reactive cross-sections for the ground state of the molecule are calculated as functions of the collision energy and the size of the cluster. The role of the size of the clusters is examined. An indirect mechanism to the reaction, which involves formation of molecular adsorption as precursors to dissociative adsorption in the low collision energy region (less than 0.1eV), is observed. Results are discussed by comparing with the other similar theoretical and experimental studies. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Cankaya Univ, Dept Comp Engn, TR-06530 Ankara, Turkey. Gazi Univ, Dept Phys, TR-06500 Ankara, Turkey. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Guvenc, ZB (reprint author), Cankaya Univ, Dept Comp Engn, TR-06530 Ankara, Turkey. EM guvenc@cankaya.edu.tr RI Ozcelik, Suleyman/J-6494-2014 OI Ozcelik, Suleyman/0000-0002-3761-3711 NR 20 TC 10 Z9 11 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 20 PY 2000 VL 454 BP 310 EP 315 DI 10.1016/S0039-6028(00)00219-3 PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 326ZB UT WOS:000087766200061 ER PT J AU Vavassori, P Grimsditch, M Fullerton, E Giovannini, L Zivieri, R Nizzoli, F AF Vavassori, P Grimsditch, M Fullerton, E Giovannini, L Zivieri, R Nizzoli, F TI Brillouin light scattering study of an exchange coupled asymmetric trilayer of Fe/Cr SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 18th European Conference on Surface Science (ECOSS 18) CY SEP 21-24, 1999 CL VIENNA UNIV TECHNOL, VIENNA, AUSTRIA SP Inst Allgemeine Phys HO VIENNA UNIV TECHNOL DE Green's function methods; iron; light scattering; magnetic interfaces; magnons AB The magnetic response of a (211) oriented asymmetric Fe trilayer [Fe(100 Angstrom)/Cr(9 Angstrom)/Fe(20 Angstrom)/Cr(20 Angstrom)/Fe(20 Angstrom)], in which the thickness of the Cr spacer layers was chosen to produce ferromagnetic coupling (F) between the two thinner Fe layers and antiferromagnetic coupling (AF) between the thicker Fe layer and the adjacent thin one, has been investigated using magnetization and Brillouin light scattering (BLS) measurements. The coupling coefficients, extracted by fitting the BLS and magnetization measurements with a theory treating the static and dynamic response on an equal footing? produced consistent values of the magnetic parameters. Our results confirm that the theoretical model used in interpreting both static and dynamic properties is valid even in systems in which F and AF coupling of the layers are simultaneously present. The theoretical model has also been extended to include the field dependence of the intensity of the Brillouin peaks. The calculated intensities are compared with the BLS spectra at different applied fields. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Ferrara, Dipartimento Fis, INFM, I-44100 Ferrara, Italy. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. RP Vavassori, P (reprint author), Univ Ferrara, Dipartimento Fis, INFM, I-44100 Ferrara, Italy. RI Fullerton, Eric/H-8445-2013; Vavassori, Paolo/B-4299-2014 OI Fullerton, Eric/0000-0002-4725-9509; Vavassori, Paolo/0000-0002-4735-6640 NR 10 TC 6 Z9 6 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 20 PY 2000 VL 454 BP 880 EP 884 DI 10.1016/S0039-6028(00)00252-1 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 326ZB UT WOS:000087766200167 ER PT J AU Schafer, J Rotenberg, E Kevan, SD Blaha, P AF Schafer, J Rotenberg, E Kevan, SD Blaha, P TI Energy gap of the spin density wave at the Cr(110) surface SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 18th European Conference on Surface Science (ECOSS 18) CY SEP 21-24, 1999 CL VIENNA UNIV TECHNOL, VIENNA, AUSTRIA SP Inst Allgemeine Phys HO VIENNA UNIV TECHNOL DE chromium; density functional calculations; magnetic phenomena (cyclotron resonance; phase transitions, etc.); magnetic surfaces; photoelectron spectroscopy ID CHROMIUM; PHOTOEMISSION AB Angle resolved photoemission is used to directly monitor the energy gap of the spin density wave of Cr at a (110) surface. Density functional calculations, including a Fermi surface contour, predict an energy gap in the surface proximity. Surface states are identified, and a near-surface gap of similar to 200 meV at room temperature is found, using spectroscopy, extending above the Fermi level. The gap exhibits an increased critical temperature of similar to 440 K and extends isotropically around the Gamma point. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Vienna Tech Univ, Inst Phys & Theoret Chem, A-1060 Vienna, Austria. RP Schafer, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RI Blaha, Peter/F-2847-2010; Rotenberg, Eli/B-3700-2009; Kevan, Stephen/F-6415-2010 OI Rotenberg, Eli/0000-0002-3979-8844; Kevan, Stephen/0000-0002-4621-9142 NR 12 TC 5 Z9 5 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 20 PY 2000 VL 454 BP 885 EP 890 DI 10.1016/S0039-6028(00)00248-X PG 6 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 326ZB UT WOS:000087766200168 ER PT J AU Chen, Y Palmer, RE Wilcoxon, JP AF Chen, Y Palmer, RE Wilcoxon, JP TI HREELS study of alkanethiol passivated gold clusters on graphite SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 18th European Conference on Surface Science (ECOSS 18) CY SEP 21-24, 1999 CL VIENNA UNIV TECHNOL, VIENNA, AUSTRIA SP Inst Allgemeine Phys HO VIENNA UNIV TECHNOL DE clusters; electron energy loss spectroscopy (EELS); self-assembly ID SELF-ASSEMBLED MONOLAYERS; ELECTRON-SCATTERING; NANOCRYSTALS; MOLECULES; DYNAMICS; IMPACT; FILMS AB Passivated metal (e.g. gold) nanoclusters consist of a metal particle core surrounded by a ligand coat. We have investigated films of gold particles passivated with alkanethiol (C8H17S) ligands deposited from solution onto a graphite surface using high-resolution electron energy loss spectroscopy (HREELS). Vibrational modes of the CH, groups of the ligands are observed, together with their overtones. Incident energy dependent measurements show an enhancement in intensity of these vibrational modes at a specific energy, similar to 10 eV, consistent with a negative ion resonance state. This observation is compared with previous studies of self-assembled monolayers of thiols on the Au (111) surface. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Birmingham, Sch Phys & Astron, Nanoscale Phys Res Lab, Birmingham B15 2TT, W Midlands, England. Sandia Natl Labs, Nanostruct & Adv Mat Dept 152, Albuquerque, NM 87185 USA. RP Chen, Y (reprint author), Univ Birmingham, Sch Phys & Astron, Nanoscale Phys Res Lab, Birmingham B15 2TT, W Midlands, England. RI Palmer, Richard/A-5366-2008; Chen, Yu/B-8858-2013 OI Palmer, Richard/0000-0001-8728-8083; NR 23 TC 8 Z9 8 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 MAY 20 PY 2000 VL 454 BP 963 EP 967 DI 10.1016/S0039-6028(00)00247-8 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 326ZB UT WOS:000087766200183 ER PT J AU Santos, AN Augustin, R Lazzari, G Galli, C Sreenan, JM Fischer, B AF Santos, AN Augustin, R Lazzari, G Galli, C Sreenan, JM Fischer, B TI The insulin-dependent glucose transporter isoform 4 is expressed in bovine blastocysts SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Article DE mammalian preimplantation development; glucose transport; in vitro culture; Glut4/Glut1 mRNA; bovine blastocyst ID GROWTH-FACTOR-I; PREIMPLANTATION DEVELOPMENT; MESSENGER-RNA; MOUSE BLASTOCYSTS; HEXOSE-TRANSPORT; GENE-EXPRESSION; HUMAN PLACENTA; EMBRYOS; OOCYTES; VITRO AB We have investigated the expression of two glucose transporter isoforms, Glut1 and 4, in 14- and 16-day-old bovine blastocysts (d14, d16) using RT-PCR, competitive RT-PCR and in situ hybridization. The blastocysts were grown in vivo or had been produced in vitro. Glut1 mRNA was detected in all blastocysts studied, Glut4 in all d14 blastocysts, but only in a few die blastocysts. Glut4 mRNA was localized in trophoblast and endoderm cells. Glut1 mRNA increased from d14 to d16 while Glut4 transcription was down-regulated in die blastocysts. The mRNA amounts varied between 0.8 to 23 pg and 3.9 to 65 fg per 100 ng embryonic RNA for Glut1 and Glut4, respectively, displaying a 100- to 1500-fold lower expression of Glut4 compared with Glut1 during blastocyst elongation. This is the first report on the expression of the insulin-sensitive Glut4 isoform in mammalian preimplantation embryos. (C) 2000 Academic Press. C1 Univ Halle Wittenberg, Fac Med, Dept Anat & Cell Biol, D-06097 Halle, Germany. CIZ, LTR, Cremona, Italy. TEAGASC, Tuam Co, Western Res & Dev Ctr, Agr & Food Dev Author, Galway, Ireland. RP Santos, AN (reprint author), Univ Halle Wittenberg, Fac Med, Dept Anat & Cell Biol, Grosse Steinstr 52, D-06097 Halle, Germany. NR 42 TC 15 Z9 15 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0006-291X J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD MAY 19 PY 2000 VL 271 IS 3 BP 753 EP 760 DI 10.1006/bbrc.2000.2646 PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 317HB UT WOS:000087219000035 ER PT J AU Skurski, P Gutowski, M Simons, J AF Skurski, P Gutowski, M Simons, J TI A bi-dipole-bound dianion SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SCF; ANIONS AB The possibility of binding one and two excess electrons by a molecule with two polar ends, each of which is capable of binding one electron, is studied using electronic structure methods. In the case of the singly charged anion, we find, as expected, a pair of nearly degenerate (2)Sigma(g)(+) and (2)Sigma(u)(+) states. For the dianion, stable open-shell triplet and singlet electronic states are reported, both of which have one electron on each polar terminus. Numerical results are presented for the mono-and di-anions of (LiCN)(2) ... HCCH ... (NCLi)(2), and our estimation of the vertical electronic stability of ((LiCN), ... HCCH ... (NCLi)(2))(2-) is 0.84 eV. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Utah, Dept Chem, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. Pacific NW Natl Lab, Richland, WA 99352 USA. RP Simons, J (reprint author), Univ Utah, Dept Chem, Henry Eyring Ctr Theoret Chem, Salt Lake City, UT 84112 USA. EM simons@chemistry.utah.edu NR 17 TC 9 Z9 9 U1 0 U2 0 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 MAY 19 PY 2000 VL 322 IS 3-4 BP 175 EP 180 DI 10.1016/S0009-2614(00)00350-X PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 318EX UT WOS:000087271900005 ER PT J AU Chehade, KAH Andres, DA Morimoto, H Spielmann, HP AF Chehade, KAH Andres, DA Morimoto, H Spielmann, HP TI Design and synthesis of a transferable farnesyl pyrophosphate analogue to Ras by protein farnesyltransferase SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID GERANYLGERANYLTRANSFERASE TYPE-I; REDUCTIVE AMINATION; SODIUM TRIACETOXYBOROHYDRIDE; BIOLOGICAL EVALUATION; PLASMA-MEMBRANE; CHOLESTEROL-BIOSYNTHESIS; BENZOYLBENZOATE ESTERS; ALLYLIC OXIDATION; SQUALENE SYNTHASE; KINETIC MECHANISM AB The posttranslational addition of a farnesyl moiety to the Ras oncoprotein is essential for its membrane localization and is required for both its biological activity and ability to induce malignant transformation. We describe the design and synthesis of a farnesyl pyrophosphate (FPP) analogue, 8-anilinogeranyl pyrophosphate 3 (AGPP), in which the omega-terminal isoprene unit of the farnesyl group has been replaced with an aniline functionality. The key steps in the synthesis are the reductive amination of the alpha,beta-unsaturated aldehyde 5 to form the lipid analogue 6, and the subsequent conversion of the allylic alcohol 7 to the chloride 8 via Ph3PCl2 followed by displacement with [(n-BU)(4)N](3)HP2O7 to give AGPP (3). AGPP is a substrate for protein farnesyltransferase (FTase) and is transferred to Ras by FTase with the same kinetics as the natural substrate, FPP. AGPP is highly selective, showing little inhibitory activity against either geranylgeranyl-protein transferase type I (GGTase I) (K-i = 0.06 mu M, IC50 = 20 mu M) or squalene synthase (IC50 = 1000 mu M). AGPP is the first efficiently transferable analogue of FPP to be modified at the omega-terminus that provides a platform from which additional analogues can be made to probe the biological function of protein farnesylation. AGPP is the first example of a class of compounds that are alternate substrates for protein isoprenylation that are not inhibitors of squalene synthase. C1 Univ Kentucky, Dept Biochem, Lexington, KY 40536 USA. Univ Kentucky, Dept Chem, Lexington, KY 40536 USA. Univ Kentucky, Kentucky Ctr Struct Biol, Lexington, KY 40536 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Natl Tritum Labeling Facil, Berkeley, CA 94720 USA. RP Spielmann, HP (reprint author), Univ Kentucky, Dept Biochem, Lexington, KY 40536 USA. NR 67 TC 51 Z9 51 U1 3 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD MAY 19 PY 2000 VL 65 IS 10 BP 3027 EP 3033 DI 10.1021/jo991735t PG 7 WC Chemistry, Organic SC Chemistry GA 318AZ UT WOS:000087262500025 PM 10814193 ER PT J AU Hu, JZ Solum, MS Wind, RA Nilsson, BL Peterson, MA Pugmire, RJ Grant, DM AF Hu, JZ Solum, MS Wind, RA Nilsson, BL Peterson, MA Pugmire, RJ Grant, DM TI H-1 and N-15 dynamic nuclear polarization studies of carbazole SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID POLYSTYRENE HETEROGENEOUS BLENDS; CHEMICAL-SHIFT TENSORS; C-13 NMR-SPECTROSCOPY; PREMIUM COALS; SOLID-STATE; INTERFACE; DNP; SPECTROMETER; BIOMOLECULES; RELAXATION AB N-15 NMR experiments, combined with dynamic nuclear polarization (DNP), are reported on carbazole doped with the stable free radical 1,3 bisdiphenylene-2-phenylallyl (BDPA). Doping shortens the nuclear relaxation times and provides paramagnetic centers that can be used to enhance the nuclear signal by means of DNP so that N-15 NMR experiments can be done in minutes. The factors were measured in a 1.4 T external field, using both unlabeled and 98% N-15 labeled carbazole with doping levels varying between 0.65 and 5.0 wt % BDPA. A doping level of approximately 1 wt % produced optimal results. DNP enhancement factors of 35 and 930 were obtained for H-1 and N-15, respectively making it possible to perform N-15 DNP NMR experiments at the natural abundance level. C1 Brigham Young Univ, Dept Chem, Provo, UT 84602 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Utah, Dept Chem & Fuels Engn, Salt Lake City, UT 84112 USA. Battelle Pacific NW Natl Lab, Environm & Mol Sci Lab, Richland, WA 99352 USA. RP Pugmire, RJ (reprint author), Brigham Young Univ, Dept Chem, Provo, UT 84602 USA. RI Hu, Jian Zhi/F-7126-2012 NR 38 TC 11 Z9 12 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 18 PY 2000 VL 104 IS 19 BP 4413 EP 4420 DI 10.1021/jp9938011 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313MJ UT WOS:000087003200010 ER PT J AU Wang, XB Wang, LS AF Wang, XB Wang, LS TI Experimental observation of a very high second electron affinity for ZrF6 from photodetachment of gaseous ZrF62- doubly charged anions SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID REPULSIVE COULOMB BARRIER; TANDEM MASS-SPECTROMETRY; GAS-PHASE; NEGATIVE-IONS; PHOTOELECTRON-SPECTROSCOPY; CARBON CLUSTERS; CORRESPONDING NEUTRALS; CONSTRUCTION PRINCIPLE; IONIZATION-POTENTIALS; METAL HEXAFLUORIDES AB We report a photodetachment photoelectron spectroscopy study of a doubly charged anion, ZrF62-, in the gas phase at two photon energies: 6.424 (193 nm) and 7.865 (157 nm) eV. The adiabatic detachment energy, i.e., the second electron affinity of ZrF6, was measured to be extremely high, 2.9(0.2) eV. The vertical detachment energy (VDE) was measured to be 3.4(0.1) eV. Two excited states were also observed for the ZrF6- singly charged anion with VDEs at 4.0 and 4.6 eV, respectively. The repulsive Coulomb barrier and hence the intramolecular Coulomb repulsion in ZrF62-, was estimated from the photon-energy-dependent spectra to be similar to 2.4 eV. The ZrF62- dianion was observed to be metastable with a half-life of similar to 4 s under our experimental conditions, confirming theoretical predictions that ZrF62- is thermodynamically unstable against loss of an F-, despite its extremely high electronic stability. We also performed experiment for the singly charged ZrF5-, but could not observe photodetachment even at 157 nm, the highest photon energy available to us. Thus, we estimated that the electron affinity of ZrF5 is larger than 7.8 eV, the highest electron affinity yet confirmed experimentally. C1 Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Wang, LS (reprint author), Washington State Univ, Dept Phys, 2710 Univ Dr, Richland, WA 99352 USA. NR 69 TC 34 Z9 35 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 18 PY 2000 VL 104 IS 19 BP 4429 EP 4432 DI 10.1021/jp000362t PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313MJ UT WOS:000087003200012 ER PT J AU Park, SH Sposito, G AF Park, SH Sposito, G TI Monte Carlo simulation of total radial distribution functions for interlayer water in Li-, Na-, and K-montmorillonite hydrates SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; NEUTRON-DIFFRACTION; CLAY-MINERALS; POTASSIUM; SODIUM; SMECTITES; SURFACE AB Recent H-1/D-2 isotopic-difference neutron diffraction experiments on interlayer water in the two-layer hydrates of Wyoming montmorillonite with Li+ or Na+ counterions have shown that the organization of the water molecules differs from that in the bulk liquid. Monte Carlo simulations were performed to investigate molecular mechanisms underlying these structural differences in terms of radial distribution functions for H-O and H-H spatial correlations. Our simulations of the first-order difference total radial distribution function, G(H)(r), for interlayer water were in good agreement with published experimental data based on H-1/D-2 isotopic-difference diffraction patterns for the two-layer hydrates of Na- and Li-montmorillonite. Detailed examination of our results showed that the H-O and H-H spatial correlations found among interlayer water molecules differ from those obtained in the bulk liquid. Moreover, O-O spatial correlations are longer-ranged than in the bulk liquid because of cation solvation effects. A Monte Carlo simulation of G(H)(r) for the two-layer hydrate of K-montmorillonite predicted differences from those of the other two montmorillonite hydrates that should be observable by neutron diffraction. C1 Lawrence Berkeley Lab, Div Earth Sci, Dept Geochem, Berkeley, CA 94720 USA. RP Park, SH (reprint author), Lawrence Berkeley Lab, Div Earth Sci, Dept Geochem, Mail Stop 90-1116, Berkeley, CA 94720 USA. EM spark@nature.berkeley.edu NR 26 TC 51 Z9 53 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 18 PY 2000 VL 104 IS 19 BP 4642 EP 4648 DI 10.1021/jp993017g PG 7 WC Chemistry, Physical SC Chemistry GA 313MP UT WOS:000087003700009 ER PT J AU Snyder, JA Alfonso, DR Jaffe, JE Lin, ZJ Hess, AC Gutowski, M AF Snyder, JA Alfonso, DR Jaffe, JE Lin, ZJ Hess, AC Gutowski, M TI Periodic density functional LDA and GGA study of CO adsorption at the (001) surface of MgO SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID GENERALIZED GRADIENT APPROXIMATION; HARTREE-FOCK; CARBON-MONOXIDE; MGO(001) SURFACE; MODEL CLUSTER; BONDING MECHANISM; MGO(100) SURFACE; MOLECULES; ENERGY; CHEMISORPTION AB The deficiencies of the local density approximation (LDA) to describe weakly adsorbed species on ionic surfaces are exposed in the current study of CO on the (001) surface of MgO. We applied a periodic formulation of density functional theory with crystal orbitals and charge density expanded as linear combinations of atomic orbitals of Gaussian form. The binding was investigated for four orientations of the CO molecule: either the carbon or oxygen atom of CO down over either the surface magnesium cation or oxygen anion. We find that the carbon down over the magnesium cation is the only noticeably attractive configuration, when basis set superposition error is corrected for, and we estimate the binding energy of CO to be 1.9 kcal/mol for the Perdew, Burke, and Enzerhof (PBE96) functional. The binding energy obtained in the LDA approximation is as large as 7.4 kcal/mol. For the C-down-over-Mg configuration, the CO stretching frequency shift is only 4 cm(-1) for the PBE96 functional. This binding energy, vibrational shift, and our analysis of density of states indicate that little chemical bonding accompanies the adsorption. The values of our binding energy and vibrational shift support a suggestion by Nygren and Pettersson [J. Chem. Phys, 1996, 105, 9339] that the CO adsorption discussed by He et al. [Surf. Sci. 1992, 261, 164] actually takes place at defect sites on the (001) surface of MgO. C1 Pacific NW Natl Lab, Dept Mat Sci, Richland, WA 99352 USA. Numtek, Vancouver, BC V5N 1Y9, Canada. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. RP Gutowski, M (reprint author), Pacific NW Natl Lab, Dept Mat Sci, Richland, WA 99352 USA. RI Lin, Zijing/D-4050-2009 NR 62 TC 37 Z9 37 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 18 PY 2000 VL 104 IS 19 BP 4717 EP 4722 DI 10.1021/jp000820y PG 6 WC Chemistry, Physical SC Chemistry GA 313MP UT WOS:000087003700021 ER PT J AU Walla, PJ Yom, J Krueger, BP Fleming, GR AF Walla, PJ Yom, J Krueger, BP Fleming, GR TI Two-photon excitation spectrum of light-harvesting complex II and fluorescence upconversion after one- and two-photon excitation of the carotenoids SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID ENERGY-TRANSFER; HIGHER-PLANTS; PHOTOSYSTEM-II; RHODOBACTER-SPHAEROIDES; 2-PHOTON FLUORESCENCE; CHLOROPHYLL-A; GREEN PLANTS; S-1 STATE; SPECTROSCOPY; DYNAMICS AB The two-photon excitation (TPE) spectrum of light-harvesting complex II (LHC II) has been measured in the spectral region of 1000-1600 nm, corresponding to one-photon wavelengths of 500-800 nm. We observed a band with an origin at similar to 2 x 660 nm (ca. 15 100 +/- 300 cm(-1)) and a maximum at similar to 2 x 600 nm. The line shape and origin of this band strongly suggest that the observed signal is due to the two-photon-allowed S(1) state of the energy-transferring carotenoids (Car) in LHC II. We also report the time dependence of the upconverted chlorophyll (Chl) fluorescence after TPE at the maximum of the observed band. Surprisingly, a fast rise of 250 +/- 50 fs followed by a multiexponential decay on the picosecond time scale was observed. This result provides strong indication that there is a fast energy transfer even from the dipole-forbidden Car S1 state to the Chl's. The sub picosecond energy transfer from the Car S1 state is likely a consequence of the large number of energy-accepting Chls in van der Waals contact with the central Car's in LHC II. We also present upconversion data of the Car S(2), Chi a, and Chi b fluorescence observed after oner-photon excitation into the dipole-allowed Car S2 state. The lifetime of the Car S2 State is similar to 120 +/- 30 fs. With the observed time constants we are able to calculate quantum yields for the different possible pathways contributing to the overall Car to Chi energy transfer in LHC II. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Fleming, GR (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. NR 49 TC 90 Z9 91 U1 2 U2 23 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 18 PY 2000 VL 104 IS 19 BP 4799 EP 4806 DI 10.1021/jp9943023 PG 8 WC Chemistry, Physical SC Chemistry GA 313MP UT WOS:000087003700031 ER PT J AU Csaki, C Erlich, J Hollowood, TJ AF Csaki, C Erlich, J Hollowood, TJ TI Graviton propagators, brane bending and bending of light in theories with quasi-localized gravity SO PHYSICS LETTERS B LA English DT Article AB We derive the graviton propagator on the brane for theories with quasi-localized gravity. In these models the ordinary 4D graviton is replaced by a resonance in the spectrum of massive Kaluza-Klein modes, which can decay into the extra dimension. We find that the effects of the extra polarization in the massive graviton propagator is exactly cancelled by the bending of the brane due to the matter sources, up to small corrections proportional to the width of the resonance. Thus at intermediate scales the classic predictions of Einstein's gravity are reproduced in these models to arbitrary precision. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. Univ Wales, Dept Phys, Swansea SA2 8PP, W Glam, Wales. RP Csaki, C (reprint author), Univ Calif Los Alamos Natl Lab, Div Theory, POB 1663,T-8, Los Alamos, NM 87545 USA. NR 49 TC 41 Z9 41 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 MAY 18 PY 2000 VL 481 IS 1 BP 107 EP 113 DI 10.1016/S0370-2693(00)00435-4 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 317EQ UT WOS:000087213400016 ER PT J AU Gailer, J George, GN Pickering, IJ Prince, RC Ringwald, SC Pemberton, JE Glass, RS Younis, HS DeYoung, DW Aposhian, HV AF Gailer, J George, GN Pickering, IJ Prince, RC Ringwald, SC Pemberton, JE Glass, RS Younis, HS DeYoung, DW Aposhian, HV TI A metabolic link between arsenite and selenite: The seleno-bis(S-glutathionyl) arsinium ion SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID GLUTATHIONE; ARSENATE AB Among the most startling observations in mammalian toxicology is that a lethal dose of selenium can be overcome by an otherwise lethal dose of arsenic. We report the molecular basis of this antagonism. Using X-ray absorption spectroscopy we have identified a new arsenic-selenium compound in the bile of rabbits injected with aqueous selenite and arsenite solutions. This compound contains equimolar arsenic and selenium and exhibits X-ray absorption spectra which are essentially identical with those of a synthetic species in solution which we have identified spectroscopically as the seleno-bis(S-glutathionyl) arsinium ion. The in vivo detection of this compound links the mammalian metabolism of arsenite, selenite, and sulfur. It provides a molecular basis for the antagonistic interaction between these metalloid compounds, and a potential explanation of the association of cancer with prolonged intake of inorganic arsenic in humans. C1 Univ Arizona, Dept Mol & Cellular Biol, Tucson, AZ 85721 USA. Univ Arizona, Dept Chem, Tucson, AZ 85721 USA. Univ Arizona, Dept Pharmacol & Toxicol, Tucson, AZ 85721 USA. Univ Arizona, Dept Univ Anim Care, Tucson, AZ 85721 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Exxon Mobil Res & Engn Co, Annandale, NJ 08801 USA. RP Gailer, J (reprint author), Univ Arizona, Dept Mol & Cellular Biol, Tucson, AZ 85721 USA. RI George, Graham/E-3290-2013; Pickering, Ingrid/A-4547-2013; OI Pickering, Ingrid/0000-0002-0936-2994 NR 27 TC 101 Z9 101 U1 4 U2 15 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 MAY 17 PY 2000 VL 122 IS 19 BP 4637 EP 4639 DI 10.1021/ja993064m PG 3 WC Chemistry, Multidisciplinary SC Chemistry GA 315MT UT WOS:000087118100014 ER PT J AU Vargas, R Garza, J Dixon, DA Hay, BP AF Vargas, R Garza, J Dixon, DA Hay, BP TI How strong is the C-alpha-H center dot center dot center dot O=C hydrogen bond? SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID DENSITY FUNCTIONAL CALCULATIONS; NEUTRON-DIFFRACTION DATA; METAL-AMIDE COMPLEXES; O INTERACTIONS; BASIS-SETS; AB-INITIO; CRYSTALLOGRAPHIC EVIDENCE; MOLECULAR CALCULATIONS; GAS-PHASE; H...O AB Although the existence of C-alpha-H...O=C hydrogen bonds in protein structures recently has been established, little is known about their strength and, therefore, the relative importance of these interactions. We have discovered that similar interactions occur in N,N-dimethylformamide dimers. High level nb initio calculations (MP2/aug-cc-pTZV) yield electronic association energies (D-e) and association enthalpies (Delta H-298) for four dimer geometries. These data provide a lower limit of D-e = -2.1 kcal mol(-1) for the C-alpha-H...O=C hydrogen bond. A linear correlation between C-H...O bond energies and gas-phase proton affinities is reported. The gas-phase anion proton affinity of a peptide C-alpha-H hydrogen was calculated (355 kcal mol(-1)) and used to estimate values of D-e = -4.0 +/- 0.5 kcal mol(-1) and Delta H-298 = -3.0 +/- 0.5 kcal mol(-1) for the C-alpha-H...O=C hydrogen bond. The magnitude of this interaction, roughly one-half the strength of the N-H...O=C hydrogen bond, suggests that C-alpha-H...O=C hydrogen bonding interactions represent a hitherto unrecognized, significant contribution in the determination of protein conformation. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Autonoma Metropolitana Iztapalapa, Dept Quim, Div Ciencias Basicas & Ingn, Mexico City 09340, DF, Mexico. RP Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Garza, Jorge/H-9395-2016; Garza-Olguin, Jorge/N-3106-2016 OI Garza, Jorge/0000-0003-4249-6078; Garza-Olguin, Jorge/0000-0003-4249-6078 NR 90 TC 346 Z9 353 U1 6 U2 46 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 MAY 17 PY 2000 VL 122 IS 19 BP 4750 EP 4755 DI 10.1021/ja993600a PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 315MT UT WOS:000087118100027 ER PT J AU Haw, JF Nicholas, JB Song, WG Deng, F Wang, ZK Xu, T Heneghan, CS AF Haw, JF Nicholas, JB Song, WG Deng, F Wang, ZK Xu, T Heneghan, CS TI Roles for cyclopentenyl cations in the synthesis of hydrocarbons from methanol on zeolite catalyst HZSM-5 SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID SOLID-STATE NMR; IN-SITU NMR; DIMETHYL ETHER FORMATION; BRONSTED ACID SITES; CARBON-CARBON BOND; REACTION-MECHANISM; CYCLOPROPYLCARBINYL CATIONS; HETEROGENEOUS CATALYSIS; THEORETICAL CHEMISTRY; CARBENIUM IONS AB In situ C-13 NMR measurements on samples prepared using a pulse-quench catalytic reactor show that the 1,3-dimethylcyclopentenyl carbenium ion (1) is an intermediate in the synthesis of toluene from ethylene on zeolite catalyst HZSM-5. Cation 1 forms in less than 0.5 s when ethylene is pulsed onto the catalyst bed at 623 K, and its presence obviates the kinetic induction period for conversion of a subsequent pulse of dimethyl ether, or methanol, into olefins (MTO chemistry). The kinetic induction period returns when the interval between pulses is many times the half-life of 1 in the catalyst bed. Density functional theory calculations (B3LYP/ 6-311G**) on a cluster model of the zeolite confirm that I is stable in the zeolite as a free cation and suggest why the alternative framework alkoxy is not observed. A pi complex of the neutral cyclic diene is only 2.2 kcal/mol higher in energy than that of the ion pair. Theoretical (GIAO-MP2/tzp) C-13 isotropic shifts of isolated 1 are in good agreement with the experimental spectra of the cation in the zeolite. To understand how organic species entrained in the catalyst could promote MTO chemistry, we calculated a number of methylation reactions in the gas phase. We found that the diene formed by deprotonation of 1 is far more easily methylated than ethylene, propene, or toluene. The aggregate experimental and theoretical results reveal the essential features of a mechanism for MTO and methanol to gasoline (MTG) chemistry on a working catalyst. C1 Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Texas A&M Univ, Dept Chem, College Stn, TX 77842 USA. RP Haw, JF (reprint author), Univ So Calif, Loker Hydrocarbon Res Inst, Univ Pk, Los Angeles, CA 90089 USA. RI Song, Weiguo/D-6041-2016 OI Song, Weiguo/0000-0001-5390-6787 NR 65 TC 168 Z9 177 U1 5 U2 79 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 MAY 17 PY 2000 VL 122 IS 19 BP 4763 EP 4775 DI 10.1021/ja994103x PG 13 WC Chemistry, Multidisciplinary SC Chemistry GA 315MT UT WOS:000087118100029 ER PT J AU Shen, MR Downing, KH Balhorn, R Hud, NV AF Shen, MR Downing, KH Balhorn, R Hud, NV TI Nucleation of DNA condensation by static loops: Formation of DNA toroids with reduced dimensions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID TRIVALENT CATIONS; PLASMID DNA; CURVATURE; ADENINE; PARTICLES; COMPLEXES; TRACTS; SIZE C1 Georgia Inst Technol, Sch Chem & Biochem, Parker H Petit Inst Bioengn & Biosci, Atlanta, GA 30332 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. RP Hud, NV (reprint author), Georgia Inst Technol, Sch Chem & Biochem, Parker H Petit Inst Bioengn & Biosci, Atlanta, GA 30332 USA. NR 28 TC 52 Z9 53 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 17 PY 2000 VL 122 IS 19 BP 4833 EP 4834 DI 10.1021/ja000200a PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 315MT UT WOS:000087118100045 ER PT J AU Webster, CR Michelsen, HA Gunson, MR Margitan, JJ Russell, JM Toon, GC Traub, WA AF Webster, CR Michelsen, HA Gunson, MR Margitan, JJ Russell, JM Toon, GC Traub, WA TI Response of lower stratospheric HCl/Cl-y to volcanic aerosol: Observations from aircraft, balloon, space shuttle, and satellite instruments SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFURIC-ACID; OZONE DEPLETION; MT-PINATUBO; ARCTIC STRATOSPHERE; BORNE MEASUREMENTS; ATMOS MEASUREMENTS; SULFATE AEROSOLS; ER-2 AIRCRAFT; CHLORINE; CLO AB Vertical profiles of HCl/Cl-y measured by space shuttle (Atmospheric Trace Molecule Spectroscopy (ATMOS)) and balloon (MkIV) instruments from 1985 through 1994 show that the increased volcanic aerosol from Mount Pinatubo had little effect on chlorine partitioning above 21 km. Below 21 km, however, large changes in HCl/l(y) were observed. Aircraft (Aircraft Laser Infrared Absorption Spectrometer), balloon (MkIV, Far Infrared Spectrometer 2), space shuttle (ATMOS), and satellite (Halogen Occultation Experiment) measurements below 21 km reveal an increase in HCl/Cl-y between early 1993 and late 1997 of 31 +/- 9%. This growth rate is 2 to 3 times larger than model estimates of the effect of the change in aerosol surface area and volume over this time period. For 1993 the five independent direct measurements of HCl/Cl-y produce a mean value of 0.57 +/- 0.05, whereas by 1997 the mean value was 0.75 +/- 0.07, in excellent agreement with the pre-Pinatubo mean of 0.74 +/- 0.11. Measurements made in 1992 at the peak of the post-Pinatubo midlatitude aerosol loading demonstrate large variability, which is qualitatively consistent with model predictions. This variability appears to be attributable to the temperature sensitivity of the Cl-y partitioning when aerosol abundances are high. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Sandia Natl Labs, Livermore, CA 94551 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Webster, CR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM cwebster@alpha1.jpl.nasa.gov NR 56 TC 6 Z9 6 U1 0 U2 1 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 MAY 16 PY 2000 VL 105 IS D9 BP 11711 EP 11719 DI 10.1029/1999JD901135 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315RA UT WOS:000087125700015 ER PT J AU Carpick, RW Mayer, TM Sasaki, DY Burns, AR AF Carpick, RW Mayer, TM Sasaki, DY Burns, AR TI Spectroscopic ellipsometry and fluorescence study of thermochromism in an ultrathin poly(diacetylene) film: Reversibility and transition kinetics SO LANGMUIR LA English DT Article ID LANGMUIR-BLODGETT-FILMS; GAS-WATER INTERFACE; POLYDIACETYLENE MONOLAYER; OPTICAL-PROPERTIES; CD2+ SALTS; POLYMERIZATION; DIACETYLENE; ANISOTROPY; LIPOSOMES; CRYSTALS AB We have investigated the thermochromic transition of an ultrathin poly(diacetylene) film. The Langmuir film is composed of three layers of polymerized 10,12-pentacosadiynoic acid [CH3(CH2)(11)C=CC=C(CH2)(8)-COOH] (poly-PCDA) organized into crystalline domains on a silicon substrate. Spectroscopic ellipsometry and fluorescence intensity measurements are obtained with in situ temperature control. Poly-PCDA films exhibit a reversible thermal transition between the initial blue form and an intermediate "purple" form that exists only at elevated temperature (between 303 and 333 K), followed by an irreversible transition to the red form after annealing above 320 K. We propose that the purple form is thermally distorted blue poly-PCDA and may represent a transitional configuration in the irreversible conversion to red. This hypothesis is supported by the appearance of unique features in the absorption spectra for each form as derived from the ellipsometry measurements. Significant fluorescence emission occurs only with the red form and is reduced at elevated temperatures while the absorption remains unchanged. Reduced emission is likely related to thermal fluctuations of the hydrocarbon side chains. Time-resolved fluorescence measurements of the irreversible transition have been performed. Using a first-order kinetic analysis of these measurements, we deduce an energy barrier of 17.6 +/- 1.1 kcal mol(-1) between the blue and red forms. C1 Sandia Natl Labs, Biomol Mat & Interfaces Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Chem Proc Sci Dept, Albuquerque, NM 87185 USA. RP Burns, AR (reprint author), Sandia Natl Labs, Biomol Mat & Interfaces Dept, POB 5800, Albuquerque, NM 87185 USA. NR 38 TC 83 Z9 83 U1 6 U2 31 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 16 PY 2000 VL 16 IS 10 BP 4639 EP 4647 DI 10.1021/la991580k PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 313NR UT WOS:000087006200037 ER PT J AU Doelsch, E Rose, J Masion, A Bottero, JY Nahon, D Bertsch, PM AF Doelsch, E Rose, J Masion, A Bottero, JY Nahon, D Bertsch, PM TI Speciation and crystal chemistry of iron(III) chloride hydrolyzed in the presence of SiO4 ligands. 1. An FeK-edge EXAFS study SO LANGMUIR LA English DT Article ID NATURAL ORGANIC-MATTER; X-RAY-ABSORPTION; FERRIC-CHLORIDE; FERRIHYDRITE; MECHANISMS; SILICATE; OXIDES; IONS; SCATTERING; NUCLEATION AB The hydrolysis of Fe-Si systems with Si/Fe ratios between 0 and 4 leads to the formation of poorly crystalline or, more frequently, of long-range disorganized precipitates. The increase of Si/Fe molar ratios results in an dramatic change of Fe polymerization. The formation of double and single corner-sharing Fe linkages is reduced compared to pure Fe hydrolysis products. The growth regime depends on the Si concentration in the system. Three-dimensional and two-dimensional growth of Fe colloids occurs at low and high Si/Fe ratios, respectively, systems with Si/Fe ratios around 1 representing a crossover between these two regimes. Though Si neighbors cannot be detected unequivocally by Fe K-edge EXAFS, their presence in the close environment of Fe atoms is evident from the change in Fe speciation. C1 CNRS Aix Marseille 3, UMR 6635, CEREGE, F-13545 Aix En Provence 04, France. Univ Georgia, AACES, Savannah River Ecol Lab, Aiken, SC 29802 USA. RP Doelsch, E (reprint author), CNRS Aix Marseille 3, UMR 6635, CEREGE, Europole Mediterraneen Arbois,BP 80, F-13545 Aix En Provence 04, France. RI doelsch, emmanuel/C-1404-2008 OI doelsch, emmanuel/0000-0002-7478-4296 NR 42 TC 56 Z9 57 U1 3 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 16 PY 2000 VL 16 IS 10 BP 4726 EP 4731 DI 10.1021/la991378h PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 313NR UT WOS:000087006200048 ER PT J AU LeMaster, DM Hernandez, G AF LeMaster, DM Hernandez, G TI NMR analysis of polyester urethane end groups and solid-phase hydrolysis kinetics SO MACROMOLECULES LA English DT Article ID MULTIPLE QUANTUM NMR; CORRELATION SPECTROSCOPY; RADICAL POLYMERIZATION; TRANSVERSE RELAXATION; DEGRADATION BEHAVIOR; METHYL-METHACRYLATE; SHIFT CORRELATION; BENZOYL PEROXIDE; SPIN SYSTEMS; 2D NMR AB Multidimensional heteronuclear solution NMR is used for end group analysis and solid-phase hydrolysis kinetics determination on a 40 kDa commercial linear polyester urethane. Pure autocatalytic acid cleavage of the ester Linkages is observed under humid atmosphere. T-1 and T-2 relaxation effects on 2D H-1-C-13 correlation spectra are analyzed so as to provide quantitative interpretation of cross-peak intensity for relative concentration measurements. A 3D C-18-purged H-1-H-1-C-13 TOCSY-HSQC experiment serves to establish extensive H-1 and C-13 spin coupling connectivities at a level of 1-2 sites per 40 kDa. Spin coupling analysis of(approximately) symmetric monomer units is facilitated by using the natural abundance C-13 enrichment to break the local symmetry. C1 Univ Calif Los Alamos Natl Lab, Biosci Div, Grp BS1, Los Alamos, NM 87545 USA. RP LeMaster, DM (reprint author), Univ Calif Los Alamos Natl Lab, Biosci Div, Grp BS1, POB 1663, Los Alamos, NM 87545 USA. NR 50 TC 10 Z9 10 U1 2 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 16 PY 2000 VL 33 IS 10 BP 3569 EP 3576 DI 10.1021/ma992030w PG 8 WC Polymer Science SC Polymer Science GA 315YB UT WOS:000087139600015 ER PT J AU Kim, T Tolmachev, AV Harkewicz, R Prior, DC Anderson, G Udseth, HR Smith, RD Bailey, TH Rakov, S Futrell, JH AF Kim, T Tolmachev, AV Harkewicz, R Prior, DC Anderson, G Udseth, HR Smith, RD Bailey, TH Rakov, S Futrell, JH TI Design and implementation of a new electrodynamic ion funnel SO ANALYTICAL CHEMISTRY LA English DT Article ID IONIZATION MASS-SPECTROMETRY; ELECTROSPRAY-IONIZATION; INTERFACE AB A new electrodynamic (rf) ion funnel has been developed and evaluated for use in the interface regions (at similar to 1-10 Torr) of atmospheric pressure ion sources (e.g., electrospray ionization (ESI) for mass spectrometry), The ion funnel consists of a ring electrode ion guide with decreasing i.d. and with a superimposed de potential gradient along the ring stack. The thicknesses of the ring electrodes and the spacings between them were reduced to 0.5 mm from 1.59 mm compared to those used for previous designs. The new ion funnel displays a significant improvement in low-mass transmission (m/z >200) and sensitivity compared to previous designs. The transmission efficiencies for electrosprayed peptides and proteins (ranging in mass from 200 to 17 000 Da) were typically 50-60% of total incoming currents from a heated capillary inlet. The transmitted ion currents were a factor of 30-56 greater than those of the standard interface for peptide samples and a factor of 18-22 greater than those for protein samples. The sensitivity gains realized at the MS detector were somewhat lower, possibly due to space charge effects in the octapole ion beam guide following the ion funnel. The improved ion transmission properties result primarily from the use of reduced spacings between ring electrodes. We also show that the ion funnel can be operated in two different modes, one using low-rf-amplitude scans, allowing fragile noncovalent complexes (as well as generally undesired adducts) to be transmitted, and the other using high-rf-amplitude scans, providing greater collisional activation and more effective adduct removal (or the dissociation of lower m/z species). C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Univ Delaware, Dept Chem & Biochem, Newark, DE 19716 USA. RP Smith, RD (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 FU NCRR NIH HHS [RR 12365] NR 9 TC 133 Z9 136 U1 6 U2 42 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 15 PY 2000 VL 72 IS 10 BP 2247 EP 2255 DI 10.1021/ac991412x PG 9 WC Chemistry, Analytical SC Chemistry GA 314TD UT WOS:000087072900010 PM 10845370 ER PT J AU Belov, ME Gorshkov, MV Udseth, HR Anderson, GA Smith, RD AF Belov, ME Gorshkov, MV Udseth, HR Anderson, GA Smith, RD TI Zeptomole-sensitivity electrospray ionization - Fourier transform ion cyclotron resonance mass spectrometry of proteins SO ANALYTICAL CHEMISTRY LA English DT Article ID MICRO-ELECTROSPRAY; FUNNEL INTERFACE; ATTOMOLE AB Methods are being developed for ultrasensitive protein characterization based upon electrospray ionization (ESI) with Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The sensitivity of a FTICR mass spectrometer equipped with an ESI source depends on the overall ion transmission, which combines the probability of ionization, transmission efficiency, and ion trapping in the FTICR cell. Our developments implemented in a 3.5 tesla FTICR mass spectrometer include introduction and optimization of a newly designed electrodynamic ion funnel in the ESI interface, improving the ion beam characteristics in a quadrupole-electrostatic ion guide interface, and modification of the electrostatic ion guide. These developments provide a detection limit of approximately 30 zmol (similar to 18 000 molecules) for proteins with molecular weights ranging from 8 to 20 kDa. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. Russian Acad Sci, Inst Energy Problems Chem Phys, Moscow 117829, Russia. RP Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Gorshkov, Mikhail/E-8522-2010; Smith, Richard/J-3664-2012; Gorshkov, Mikhail/N-4984-2013 OI Smith, Richard/0000-0002-2381-2349; Gorshkov, Mikhail/0000-0001-9572-3452 FU NCRR NIH HHS [RR12365] NR 23 TC 116 Z9 120 U1 0 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 EI 1520-6882 J9 ANAL CHEM JI Anal. Chem. PD MAY 15 PY 2000 VL 72 IS 10 BP 2271 EP 2279 DI 10.1021/ac991360b PG 9 WC Chemistry, Analytical SC Chemistry GA 314TD UT WOS:000087072900014 PM 10845374 ER PT J AU Culbertson, CT Ramsey, RS Ramsey, JM AF Culbertson, CT Ramsey, RS Ramsey, JM TI Electroosmotically induced hydraulic pumping on microchips: Differential ion transport SO ANALYTICAL CHEMISTRY LA English DT Article ID MICELLAR ELECTROKINETIC CHROMATOGRAPHY; OPEN-CHANNEL ELECTROCHROMATOGRAPHY; CAPILLARY-ELECTROPHORESIS; PCR AMPLIFICATION; SEPARATIONS; DEVICE; CHIPS; SYSTEMS; PERFORMANCE; ASSAYS AB The theory behind and operation of an electroosmotically induced hydraulic pump for microfluidic devices is reported. This microchip functional element consists of a tee intersection with one inlet channel and two outlet channels. The inlet channel is maintained at high voltage while one outlet channel is kept at ground and the other channel has no electric potential applied. A pressure-induced now of buffer is created in both outlet channels of the tee by reducing electroosmosis in the ground channel relative to that of the inlet channel. Spatially selective reduction of electroosmosis is accomplished by coating the walls of the ground channel with a viscous polymer. The pump is shown to differentially transport ions down the two outlet channels. This ion discrimination ability of the pump is examined as a function of an analyte's electrophoretic velocity. In addition, we demonstrate that an anion can be rejected from the ground channel and made to flow only into the field-free channel if the electrophoretic velocity of the anion is greater than the pressure-generated now in the ground channel. The velocity threshold at which anion rejection occurs can be selectively tuned by changing the flow resistance in the field-free channel relative to the ground channel. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Ramsey, JM (reprint author), Oak Ridge Natl Lab, POB 2008,MS 6142, Oak Ridge, TN 37831 USA. OI Culbertson, Christopher/0000-0002-6833-3237 NR 29 TC 106 Z9 108 U1 2 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 15 PY 2000 VL 72 IS 10 BP 2285 EP 2291 DI 10.1021/ac9912202 PG 7 WC Chemistry, Analytical SC Chemistry GA 314TD UT WOS:000087072900016 ER PT J AU Lettieri, J Zurbuchen, MA Jia, Y Schlom, DG Streiffer, SK Hawley, ME AF Lettieri, J Zurbuchen, MA Jia, Y Schlom, DG Streiffer, SK Hawley, ME TI Epitaxial growth of non-c-oriented SrBi2Nb2O9 on (111) SrTiO3 SO APPLIED PHYSICS LETTERS LA English DT Article ID SRBI2TA2O9 THIN-FILMS; BISMUTH TITANATE; BOUNDARIES; AXIS AB Epitaxial SrBi2Nb2O9 thin films have been grown with a (103) orientation on (111) SrTiO3 substrates by pulsed-laser deposition. Four-circle x-ray diffraction and transmission electron microscopy reveal nearly phase-pure epitaxial films. Epitaxial (111) SrRuO3 electrodes enabled the electrical properties of these (103)-oriented SrBi2Nb2O9 films to be measured. The low-field relative permittivity was 185, the remanent polarization was 15.7 mu C/cm(2), and the dielectric loss was 2.5% for a 0.5-mu m-thick film. (C) 2000 American Institute of Physics. [S0003-6951(00)01720-4]. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16803 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Lettieri, J (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16803 USA. RI Streiffer, Stephen/A-1756-2009; Zurbuchen, Mark/H-1664-2012; Schlom, Darrell/J-2412-2013 OI Zurbuchen, Mark/0000-0002-8947-6309; Schlom, Darrell/0000-0003-2493-6113 NR 29 TC 66 Z9 73 U1 1 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 15 PY 2000 VL 76 IS 20 BP 2937 EP 2939 DI 10.1063/1.126522 PG 3 WC Physics, Applied SC Physics GA 312YB UT WOS:000086970600042 ER PT J AU Zhang, AP Dang, GT Ren, F Han, J Baca, AG Shul, RJ Cho, H Monier, C Cao, XA Abernathy, CR Pearton, SJ AF Zhang, AP Dang, GT Ren, F Han, J Baca, AG Shul, RJ Cho, H Monier, C Cao, XA Abernathy, CR Pearton, SJ TI Direct-current characteristics of pnp AlGaN/GaN heterojunction bipolar transistors SO APPLIED PHYSICS LETTERS LA English DT Article ID FIELD-EFFECT TRANSISTORS; HIGH-TEMPERATURE; GAN AB AlGaN/GaN pnp heterojunction bipolar transistors were fabricated using a low-damage dry-etch process, and the dc characteristics measured up to 250 degrees C. In the common-base mode, the collector current was approximately equal to the emitter current under all conditions. Although not optimized for power operations, the devices were tested up to power densities of similar to 50 kW cm(-2). The dc current gain was in the range 20-25 at room temperature. The pnp configuration avoids the problem of high base sheet resistance encountered with npn-AlGaN/GaN devices. (C) 2000 American Institute of Physics. [S0003-6951(00)00920-7]. C1 Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Florida, Dept Mat Sci & Engn, Gainesville, FL 32611 USA. RP Zhang, AP (reprint author), Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. NR 19 TC 18 Z9 18 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 15 PY 2000 VL 76 IS 20 BP 2943 EP 2945 AR PII [S0003-6951(00)00920-7] DI 10.1063/1.126524 PG 3 WC Physics, Applied SC Physics GA 312YB UT WOS:000086970600044 ER PT J AU Inoue, T Ogletree, DF Salmeron, M AF Inoue, T Ogletree, DF Salmeron, M TI Field emission study of diamond-like carbon films with scanned-probe field-emission force microscopy SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTRON-EMISSION; THIN-FILMS AB Using a tip as an anode, a scanning force microscope (SFM) with an electrically conducting tip allows simultaneous measurement of both field-emitted currents and surface electronic properties with high lateral resolution. The principle of the method and its application to field emission from chemical vapor deposition diamond-like carbon films are presented. By simultaneously imaging the topography and field-emission current distribution with a 100 nm tip-surface separation, we correlated emission, topography, and dielectric properties. Subsequent contact SFM images of the same regions correlated topography and conductivity on the nanometer scale. The electrostatic force between tip and surface showed fluctuations on a millisecond time scale during field emission. This is probably due to charging and discharging of deep traps in the diamond-like carbon film. (C) 2000 American Institute of Physics. [S0003- 6951(00)01320-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Electrotech Lab, Mol Phys Sect, Tsukuba, Ibaraki 3058568, Japan. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Ogletree, D Frank/D-9833-2016 OI Ogletree, D Frank/0000-0002-8159-0182 NR 15 TC 15 Z9 16 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 15 PY 2000 VL 76 IS 20 BP 2961 EP 2963 AR PII [S0003-6951(00)01320-6] DI 10.1063/1.126530 PG 3 WC Physics, Applied SC Physics GA 312YB UT WOS:000086970600050 ER PT J AU LaPlante, JM O'Rourke, F Lu, XH Fein, A Olsen, A Feinstein, MB AF LaPlante, JM O'Rourke, F Lu, XH Fein, A Olsen, A Feinstein, MB TI Cloning of human Ca2+ homoeostasis endoplasmic reticulum protein (CHERP): regulated expression of antisense cDNA depletes CHERP, inhibits intracellular Ca2+ mobilization and decreases cell proliferation SO BIOCHEMICAL JOURNAL LA English DT Article DE InsP(3); senescence; signal transduction ID POTASSIUM CHANNEL GENE; CAG REPEAT; ION; RECEPTOR; RELEASE; INFLUX; PORE; HUMAN-CHROMOSOME-19; PURIFICATION; MECHANISMS AB A monoclonal antibody which blocks InsP(3)-induced Ca2+ release from isolated endoplasmic reticulum was used to isolate a novel 4.0 kb cDNA from a human erythroleukaemia (HEL) cell cDNA expression library. A corresponding mRNA transcript of approx. 4.2 kb was present in all human cell lines and tissues examined, but cardiac and skeletal muscle had an additional transcript of 6.4 kb. The identification in GenBank(R) of homologous expressed sequence tags from many tissues and organisms suggests that the gene is ubiquitously expressed in higher eukaryotes. The gene was mapped to human chromosome 19p13.1. The cDNA predicts a 100 kDa protein, designated Ca2+ homoeostasis endoplasmic reticulum protein (CHERP), with two putative transmembrane domains, multiple consensus phosphorylation sites, a polyglutamine tract of 12 repeats and regions of imperfect tryptophan and histadine octa- and nona-peptide repeats. In vitro translation of the full-length cDNA produced proteins of M, 128000 and 100000, corresponding to protein bands detected by Western blotting of many cell types. CHERP was co-localized in HEL cells with the InsP(3) receptor by two-colour immunofluorescence. Transfection of HEL cells with antisense cDNA led to an 80 % decline in CHERP within 5 days of antisense induction, with markedly decreased intracellular Ca2+ mobilization by thrombin, decreased DNA synthesis and growth arrest, indicating that the protein has an important function in Ca2+ homoeostasis, growth and proliferation. C1 Univ Connecticut, Ctr Hlth, Dept Pharmacol, Farmington, CT 06032 USA. Univ Connecticut, Ctr Hlth, Dept Physiol, Farmington, CT 06032 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Human Genome, DOE Joint Genome Inst, Livermore, CA 94550 USA. RP O'Rourke, F (reprint author), Univ Connecticut, Ctr Hlth, Dept Pharmacol, 263 Farmington Ave, Farmington, CT 06032 USA. FU NHLBI NIH HHS [HL 18937] NR 41 TC 12 Z9 14 U1 0 U2 1 PU PORTLAND PRESS PI LONDON PA 59 PORTLAND PLACE, LONDON W1N 3AJ, ENGLAND SN 0264-6021 J9 BIOCHEM J JI Biochem. J. PD MAY 15 PY 2000 VL 348 BP 189 EP 199 DI 10.1042/0264-6021:3480189 PN 1 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 324CL UT WOS:000087604200025 PM 10794731 ER PT J AU Bahr, K Duba, A AF Bahr, K Duba, A TI Is the asthenosphere electrically anisotropic? SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE electrical conductivity; anisotropy; upper mantle; lattice; preferred orientation ID UPPER-MANTLE; PARTIAL-MELT; CONDUCTIVITY; OLIVINE; BENEATH; INCREASE; HYDROGEN; EUROPE; NOISE; ROCKS AB Two techniques for resolving the conductance of an electrically conductive asthenosphere are presented. The first technique combines observatory electromagnetic data in the period range of the daily variation and longer, which provides penetration depths of 400 km and deeper, with laboratory data of the conductivity of upper mantle materials. The conductance can be estimated by this technique, but the geometry - e.g. the exact depth - is not resolved. The second technique extends the classical magnetotelluric (MT) tensor estimation and decomposition to the period range 1000-30 000 s. If an electrical asthenosphere exists, then in this period range the electromagnetic field penetrates into it (1000 s) but also through it (30 000 s). The concept of regional strike directions which has been successfully used to obtain crustal anisotropy directions is again employed at these long periods. The surprising result is that in the depth range of the asthenosphere a strong directional dependence of the conductance again occurs. Although large arrays will be necessary in order to prove that this is really conductivity anisotropy in the asthenosphere, first field results from arrays 100-200 km in extent are encouraging. The concept of a superposition of crustal and upper mantle anisotropy explains to some extent why earlier magnetotelluric determinations of the asthenosphere had little success: only in the fortunate case where a MT experiment was performed not parallel to the direction of the crustal conductor, but parallel to the asthenospheric one, is the second structure resolved. Electrical anisotropy in the uppermost mantle supports the concept of intracrystalline water, which allows for a contribution of hydrogen diffusity to the conductivity of olivine: this diffusity is highly anisotropic with respect to the crystal axis, and if the crystals are partly aligned, the conductivity measured with MT is also direction-dependent. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Inst Geophys, D-37013 Gottingen, Germany. L201 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Bahr, K (reprint author), Inst Geophys, POB 2341, D-37013 Gottingen, Germany. NR 36 TC 27 Z9 30 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD MAY 15 PY 2000 VL 178 IS 1-2 BP 87 EP 95 DI 10.1016/S0012-821X(00)00070-4 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 315YQ UT WOS:000087140900008 ER PT J AU Lahti, DW Espenson, JH AF Lahti, DW Espenson, JH TI Oxidation of sulfoxides by hydrogen peroxide, catalyzed by methyltrioxorhenium(VII) SO INORGANIC CHEMISTRY LA English DT Article ID ATOM-TRANSFER-REACTIONS; METHYLRHENIUM TRIOXIDE; OXYGEN-TRANSFER; COMPUTER-SIMULATION; ALLYLIC ALCOHOLS; MECHANISM; KINETICS; EPOXIDATION; COMPLEXES; SULFIDES AB Dialkyl and diaryl sulfoxides are oxidized to sulfones by hydrogen peroxide using methyltrioxorhenium as the catalyst. The reaction rate is negligible without a catalyst. The kinetics study was performed in CH3CN-H2O (4:1 v/v) at 298 K with [H+] at 0.1 M, conditions which make the equilibration between MTO and its peroxo complexes more rapid than the oxygen-transfer step. The values for the rate constant for the oxygen-transfer step lie in the range 0.1-3 L mol(-1) s(-1). The rate constants were significantly smaller than for the oxidation of sulfides to sulfoxides. A study of ring-substituted diaryl sulfoxides yielded kinetics results that are consistent with nucleophilic attack of the sulfur atom on the peroxide oxygen group since rho = -0.65, The results cited refer to the reactions of the diperoxo from the catalyst, MeRe(O)(eta(2)-O-2)(2)H2O. The monoperoxo complex showed no measurable reactivity toward sulfoxides, in contrast with the situation for nearly every other substrate. That unusual finding suggests a hydrogen-bonded interaction between the substrate and the diperoxorhenium compound which cannot exist with the monoperoxo compound. C1 Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Chem, Ames, IA 50011 USA. RP Espenson, JH (reprint author), Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. NR 25 TC 22 Z9 22 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 15 PY 2000 VL 39 IS 10 BP 2164 EP 2167 DI 10.1021/ic991292b PG 4 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 315QG UT WOS:000087124000025 PM 12526529 ER PT J AU Coia, GM Demadis, KD Meyer, TJ AF Coia, GM Demadis, KD Meyer, TJ TI Oxidation of ammonia in osmium polypyridyl complexes SO INORGANIC CHEMISTRY LA English DT Article ID NITRIDO COMPLEXES; ATOM TRANSFER; AZIDE ION; RUTHENIUM; ALCOHOLS; EPOXIDATION; REACTIVITY; ALDEHYDES; TUNGSTEN; LIGANDS AB The oxidations of cis- and trans-[Os(III)(tpy) (Cl)(2)(NH(3))](PF(6)), cis-[Os(II)(bpy)(2)(Cl)(NH(3))](PF(6)), and [Os(II)(tpy)(bpy)-(NH(3))](PF(6))(2) have been studied by cyclic voltammetry and by controlled-potential electrolysis. In acetonitrile or in acidic, aqueous solution, oxidation is metal-based and reversible, but as the DH is increased, oxidation and proton loss from coordinated ammonia occurs, cis- and trans-[Os(III)(tpy)(Cl)(2)(NH(3))](PF(6)) are oxidized by four electrons to sive the corresponding Os(VI) nitrido complexes, [Os(VI)(tpy)(Cl)(2)(N)](+). Oxidation of [Os(tpy)(bpy)-(NH(3))](PF(6))(2) occurs by six electrons to give [Os(tpy)(bpy)(NO)](PF(6))(3). Oxidation of cis-[Os(II)(bpy)(2)(Cl)(NH(3))]-(PF(6)) at pH 9.0 gives cis-[Os(II)(bpy)(2)(Cl)(NO)](PF(6))(2) and the mixed-valence form of the mu-N(2) dimer cis[Os(II)(bpy)(2)(Cl)(NH(3))]- [Os(bpy)(2)(Cl)](2)(mu-N(2))}(PF(6))(3) With NH(4)(+) added to the electrolyte, cis-[Os(II)(bpy)(2)(Cl)(N(2))](PF(6)) is a coproduct. The results of pi-I-dependent cyclic voltammetry measurements suggest Os(IV) as a common intermediate in the oxidation of coordinated ammonia. For cis- and trans-[Os(III)(tpy)(Cl)(2)(NH(3))](+), Os(IV) is a discernible intermediate. It undergoes further pH-dependent oxidation to [Os(VI)(tpy)(Cl)(2)(N)](+). For [Os(II)(tpy)(bpy)(NH(3))](2+), oxidation to Os(IV) is followed by hydration at the nitrogen atom and further oxidation to nitrosyl. For cis-[Os(II)(bpy)(2)(Cl)-(NH(3))](+), oxidation to Os(IV) is followed by N-N coupling and further oxidation to {cis-[Os(bpy)(2)(Cl)](2)(mu-N(2))(3+) At pH 9, N-N coupling is competitive with capture of Os(IV) by OH(-) and further oxidation, yielding cis-[Os(II)- (bpy)(2)(Cl)(NO)](2+). C1 Univ N Carolina, Dept Chem, Venable & Kenan Labs, Chapel Hill, NC 27599 USA. RP Meyer, TJ (reprint author), Los Alamos Natl Lab, MS A127, Los Alamos, NM 87545 USA. EM gcoia@its.caltech.edu; kdemadis@nalco.com; tjmeyer@lanl.gov RI Demadis, Kostas/A-7347-2010 NR 63 TC 20 Z9 20 U1 2 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0020-1669 J9 INORG CHEM JI Inorg. Chem. PD MAY 15 PY 2000 VL 39 IS 10 BP 2212 EP 2223 DI 10.1021/ic0000505 PG 12 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 315QG UT WOS:000087124000033 PM 12526537 ER PT J AU Oh, SY Nguyen, HD Paik, S AF Oh, SY Nguyen, HD Paik, S TI A Legendre-spectral element method for flow and heat transfer about an accelerating droplet SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE droplet; Legendre-spectral element method; vorticity ID LOW REYNOLDS-NUMBERS; INTERNAL CIRCULATION; TERMINAL VELOCITY; SPHERICAL DROPLET; FLUID SPHERE; UNSTEADY AB The problem of flow and heat transfer associated with a spherical droplet accelerated from rest under gravitational force is studied using a Legendre-spectral element method in conjunction with a mixed time integration procedure to advance the solution in time. An influence matrix technique that exploits the superposition principle is adapted to resolve the lack of vorticity boundary conditions and to decouple the equations from the interfacial couplings. The computed flow and temperature fields, the drag coefficient, the Nusselt number, and the interfacial velocity and vorticity are presented for a drop moving vertically in a quiescent gas of infinite extent to illustrate the evolution of the flow and temperature fields. Comparison of the predicted drag coefficient and the Nusselt number against previous numerical and experimental results indicate good agreement. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Idaho Natl Engn Environm Lab, Idaho Falls, ID 83415 USA. Chungnam Natl Univ, Dept Math, Taejon 305764, South Korea. Innovat Engn Solut, Idaho Falls, ID USA. RP Paik, S (reprint author), Idaho Natl Engn Environm Lab, Idaho Falls, ID 83415 USA. NR 23 TC 2 Z9 2 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD MAY 15 PY 2000 VL 33 IS 1 BP 59 EP 79 DI 10.1002/(SICI)1097-0363(20000515)33:1<59::AID-FLD1>3.0.CO;2-M PG 21 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA 310FV UT WOS:000086816600004 ER PT J AU Mahan, GD AF Mahan, GD TI Density variations in thermoelectrics SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THERMIONIC REFRIGERATION AB Equations are solved to give the variations in temperature, density, and potential, when a solid has electrical currents, heat currents, and particle diffusion. Solutions are presented in one dimension for currents down a bar. These solutions are used to calculate the efficiency of a thermoelectric refrigerator, which is optimized to give the coefficient of performance (COP). The COP depends upon the temperature difference Delta T, but does not depend upon the density difference Delta n between the two ends of the bar. (C) 2000 American Institute of Physics. [S0021-8979(00)03510-6]. C1 Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. RP Mahan, GD (reprint author), Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. NR 18 TC 26 Z9 26 U1 0 U2 15 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 2000 VL 87 IS 10 BP 7326 EP 7332 DI 10.1063/1.372988 PG 7 WC Physics, Applied SC Physics GA 308TY UT WOS:000086730000029 ER PT J AU Gao, Y Perkins, CL He, S Alluri, P Tran, T Thevuthasan, S Henderson, MA AF Gao, Y Perkins, CL He, S Alluri, P Tran, T Thevuthasan, S Henderson, MA TI Mechanistic study of metalorganic chemical vapor deposition of (Ba,Sr)TiO3 thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SR)TIO3 FILMS; ELECTRICAL-PROPERTIES; MOCVD; (BA; DRAM; BASRTIO3 AB The metalorganic precursor chemistry was studied on Pt(111) surfaces in a O-16(2) and O-18(2) backgrounds. Using temperature programmed desorption (TPD) and static secondary ion mass spectrometry (SIMS). The precursor chemistry of Sr(thd)(2) was found to be different on oxide covered Pt(111) surface as compared to the clean Pt(111) surface. In an oxygen ambient, TPD showed at least four different reaction processes which involved the removal of carbon from the precursor ligands on oxide covered Pt(111). In two of these, gas phase oxygen was incorporated into the oxidative products. In contrast, one carbon removing reaction was observed on the clean Pt(111) surface. Isotopic labeling experiments have also been carried out to understand the film-formation reactions in the metalorganic chemical vapor deposition of (Ba,Sr)TiO3 (BST) films. Time-of-flight SIMS and nuclear reaction analysis reveal that the oxygen in the BST films originates from both the gas phase oxidants (O-18) and the precursor ligands (O-16). The ligand substitution by gas phase O-2 plays a more prominent role in the film formation at lower temperatures. On the other hand, the reactive oxygen radicals produced by microwave plasma involved more in breaking the O-C bonds than substituting the precursor ligands for the film formation. Use of the 50% O-18(2)-50% N-2 O-16(2) mixture results in a reduction of O-18 incorporation in the BST films, indicative of the direct involvement of N2O in the film-formation reactions. The mechanistic studies are essential for understanding the new BST precursors used in this study, and provide useful information to correlate the film microstructure, step coverage, and dielectric properties with the precursor properties. (C) 2000 American Institute of Physics. [S0021-8979(00)02210-6]. C1 Pacific NW Lab, Richland, WA 99352 USA. Motorola Inc, Mat Technol Labs, Austin, TX 78721 USA. RP Gao, Y (reprint author), Pacific NW Lab, POB 999,MS K8-93, Richland, WA 99352 USA. NR 30 TC 14 Z9 14 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 2000 VL 87 IS 10 BP 7430 EP 7437 DI 10.1063/1.373005 PG 8 WC Physics, Applied SC Physics GA 308TY UT WOS:000086730000046 ER PT J AU Bhattacharyya, S Vallee, C Cardinaud, C Turban, G AF Bhattacharyya, S Vallee, C Cardinaud, C Turban, G TI Structure of nitrogenated carbon films prepared from acetylene and nitrogen mixture in electron cyclotron resonance plasma SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ENERGY-LOSS SPECTROSCOPY; DIAMOND-LIKE CARBON; A-C-H; TETRAHEDRAL AMORPHOUS-CARBON; NITRIDE THIN-FILMS; PHOTOELECTRON-SPECTROSCOPY; MECHANICAL-PROPERTIES; RAMAN-SPECTROSCOPY; OPTICAL-PROPERTIES; VAPOR-DEPOSITION AB Amorphous nitrogenated carbon (a-CNx) films have been prepared from a mixture of acetylene and nitrogen gas in an electron cyclotron resonance plasma and characterized by electron energy-loss spectroscopy (EELS), spectroscopic ellipsometry (SE), Fourier transformed infrared (FTIR) spectroscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. From EELS and SE, a significant change in the pi plasmon peak position and a reduction of its area is observed in the carbon films after nitrogen introduction, which suggest that there is no further development of graphitic structure. The features of D and G peaks observed from Raman as well as FTIR spectra support a decrease in the amount of sp(2) bonded carbon in the a-CNx films. Valence band spectra using He I and He II excitations show that the p-pi band becomes less intense upon nitrogen addition. A comparative study between the characteristics of these films and the films deposited from a methane-nitrogen mixture using an identical procedure is also presented. It is found that the structural changes in these films upon nitrogen incorporation are different, indicating a definite role of the precursors on the film structure. (C) 2000 American Institute of Physics. [S0021-8979(00)04809-X]. C1 CNRS, Inst Mat Jean Rouxel, LPCM, F-44322 Nantes 3, France. RP Bhattacharyya, S (reprint author), Argonne Natl Lab, MSD CHM, Bldg 200,9700 S Cass Ave, Argonne, IL 60439 USA. RI Cardinaud, Christophe/G-3074-2012; Bhattacharyya, Somnath/M-1867-2015 OI Cardinaud, Christophe/0000-0002-9753-8848; Bhattacharyya, Somnath/0000-0002-6435-7864 NR 49 TC 9 Z9 9 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 2000 VL 87 IS 10 BP 7524 EP 7532 DI 10.1063/1.373018 PG 9 WC Physics, Applied SC Physics GA 308TY UT WOS:000086730000059 ER PT J AU Chen, KD Iglesia, E Bell, AT AF Chen, KD Iglesia, E Bell, AT TI Kinetic isotopic effects in oxidative dehydrogenation of propane on vanadium oxide catalysts SO JOURNAL OF CATALYSIS LA English DT Article DE propane; oxidative dehydrogenation; vanadium oxide ID ALKANES AB Kinetic isotopic effects (KIEs) for oxidative dehydrogenation of propane were measured on 10 wt% V2O5/ZrO2. Normal KIEs were obtained using CH3CH2CH3 and CD3CD2CD3 as reactants for primary dehydrogenation (2.8) and combustion (1.9) of propane and for secondary combustion of propene (2.6), suggesting that in all cases C-H bond dissociation is a kinetically relevant step. CH3CH2CH3 and CH3CD2CH3 reactants led to normal KIEs for dehydrogenation (2.7) and combustion (1.8) of propane, but to a very small KIE (1.1) for propene combustion. These results show that the methylene C-H bond is activated in the rate-determining steps for propane dehydrogenation and combustion reactions. The rate-determining step in secondary propene combustion involves the allylic C-H bond. In each reaction, the weakest C-H bond in the reactant is cleaved in the initial C-H bond activation step. The measured propane oxidative dehydrogenation KIEs are in agreement with theoretical estimates using a sequence of elementary steps, reaction rate expression, and transition state theory. The much smaller KIE for propane oxidative dehydrogenation (2.8) than the maximum KIE (6) expected for propane thermal dehydrogenation indicates the participation of lattice oxygen. The different KIE values for propane primary dehydrogenation and combustion suggest that these two reactions involve different lattice oxygen sites. (C) 2000 Academic Press. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA. RP Iglesia, E (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Chem, Berkeley, CA 94720 USA. RI Iglesia, Enrique/D-9551-2017; OI Iglesia, Enrique/0000-0003-4109-1001; Bell, Alexis/0000-0002-5738-4645 NR 19 TC 105 Z9 110 U1 2 U2 24 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9517 J9 J CATAL JI J. Catal. PD MAY 15 PY 2000 VL 192 IS 1 BP 197 EP 203 DI 10.1006/jcat.2000.2832 PG 7 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 317QK UT WOS:000087238300020 ER PT J AU Xie, DQ Guo, H Peterson, KA AF Xie, DQ Guo, H Peterson, KA TI Accurate ab initio near-equilibrium potential energy and dipole moment functions of the ground electronic state of ozone SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFIGURATION-INTERACTION CALCULATIONS; DISCRETE VARIABLE REPRESENTATION; VARIATIONAL WAVE-FUNCTIONS; HARMONIC FORCE-FIELD; VIBRATIONAL FREQUENCIES; CHAPPUIS BAND; HARTLEY BAND; CORIOLIS INTERACTION; TRIATOMIC-MOLECULES; PHOTO-DISSOCIATION AB We report a highly correlated multireference configuration interaction calculation of the near-equilibrium potential energy surface of ozone using a large correlation consistent basis set. Three-dimensional analytical expressions are obtained for the potential energy and dipole moment functions using least-squares fits to ab initio points near the C-2v equilibrium geometry. Low-lying vibrational band origins of O-16(3) and some of its isotopic variants are calculated using the ab initio potential energy function. The calculated fundamental frequencies for the symmetric stretching and bending vibrations are within about 3 cm(-1) of the observed values, while that for the antisymmetric stretch deviates from experiment by about 13 cm(-1). The agreement with experiment can be significantly improved if the ab initio potential energy function is scaled in the antisymmetric stretching coordinate. Absolute infrared absorption intensities are also calculated using ab initio electric dipole moment functions and in good agreement with the available experimental data. (C) 2000 American Institute of Physics. [S0021-9606(00)30219-7]. C1 Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. Univ New Mexico, Albuquerque High Performance Comp Ctr, Albuquerque, NM 87131 USA. Washington State Univ, Dept Chem, Richland, WA 99352 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Xie, DQ (reprint author), Univ New Mexico, Dept Chem, Albuquerque, NM 87131 USA. RI Guo, Hua/J-2685-2014 OI Guo, Hua/0000-0001-9901-053X NR 67 TC 43 Z9 45 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 2000 VL 112 IS 19 BP 8378 EP 8386 DI 10.1063/1.481442 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 309QC UT WOS:000086778300021 ER PT J AU Peterson, KA Francisco, JS AF Peterson, KA Francisco, JS TI Low-lying excited states of HOOOCl and HOOOBr SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; GAUSSIAN-BASIS SETS; RELATIVE STABILITIES; ISOMERS; CHEMISTRY; SPECTRA; HCLO2; ARGON AB A theoretical investigation of the low-lying singlet and triplet electronic states of HOOOCl and HOOOBr is presented. Calculations of excitation energies and oscillator strengths using CASSCF, first-order CI, MRCI and the equation of motion coupled-cluster singles and doubles methods are presented. The calculations predict that for HOOOCl and HOOOBr there are two singlet states that are accessible by wavelengths longer than 235 nm. These transitions, however, are predicted to be relatively weak. Spin-orbit calculations yield oscillator strengths for the lowest two triplet states of HOOOBr that are only one order of magnitude smaller than those of its low-lying singlet states. (C) 2000 American Institute of Physics. [S0021- 9606(00)30518-9]. C1 Washington State Univ, Dept Chem, Richland, WA 99352 USA. Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Purdue Univ, Dept Earth & Atmospher Sci, W Lafayette, IN 47907 USA. RP Peterson, KA (reprint author), Washington State Univ, Dept Chem, Richland, WA 99352 USA. NR 27 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 2000 VL 112 IS 19 BP 8483 EP 8486 DI 10.1063/1.481450 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 309QC UT WOS:000086778300032 ER PT J AU Ostergren, JD Trainor, TP Bargar, JR Brown, GE Parks, GA AF Ostergren, JD Trainor, TP Bargar, JR Brown, GE Parks, GA TI Inorganic ligand effects on Pb(II) sorption to goethite (alpha-FeOOH) - I. Carbonate SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE Pb; carbonate; sorption; goethite; EXAFS; ATR-FTIR; bond valence ID MOLECULAR STATICS CALCULATIONS; AMORPHOUS IRON OXYHYDROXIDE; BOND-VALENCE DETERMINATION; OXIDE-WATER INTERFACES; X-RAY-ABSORPTION; SIMULATED GASTRIC CONDITIONS; SURFACE FUNCTIONAL-GROUPS; SOLID-SOLUTION INTERFACE; LEAD BIOAVAILABILITY; SYNTHETIC GOETHITE AB Macroscopic measurements show that Pb(II) uptake on iron(hydr)oxides can be altered significantly by dissolved carbonate (enhanced up to 18% at pH 5 and decreased above pH similar to 6.5 in analyses at 1 atm CO(2)). This study elucidates the molecular-scale processes giving rise to these macroscopic effects by characterizing the structures of Pb(II) sorption complexes formed an goethite (alpha-FeOOH) in the presence of carbonate using in situ Pb L(III)-EXAFS and ATR-FTIR spectroscopies. Bond valence and structural constraints are applied to develop mineral surface site-specific models for Pb sorption. Under all conditions studied (pH 5-7, Gamma(Pb) = 0.4-4 mu mol/m(2), and P(CO2) = 0-1 atm), Pb(II) forms predominantly inner-sphere edge-sharing (bidentate and/or tridentate) complexes with Fe(O,OH)(6) octahedra (R(Pb-Fe) similar to 3.3 Angstrom). Corner-sharing complexes (R(Pb-Fe) similar to 3.9 Angstrom) are observed only in low pH (5) samples (P(CO2) 0-1 atm). Consistent with this pH sensitivity, site-specific analyses suggest that the relative abundance of corner-sharing sites reflects changes in the proton affinity of triply coordinated sites on the goethite (110) surface as suggested previously. FTIR results suggest the existence of ternary surface complexes in which carbonate groups bond to Pb as monodentate ligands. EXAFS data indicate that these ternary complexes are bound to the surface through Pb, forming metal-bridged (Type A) complexes. Findings are summarized as structural models and corresponding mineral surface site-specific chemical reactions. (C) 2000 Academic Press. C1 Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. RP Brown, GE (reprint author), Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. EM gordon@pangea.stanford.edu NR 78 TC 79 Z9 80 U1 5 U2 38 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD MAY 15 PY 2000 VL 225 IS 2 BP 466 EP 482 DI 10.1006/jcis.1999.6701 PG 17 WC Chemistry, Physical SC Chemistry GA 313EX UT WOS:000086988300027 ER PT J AU Ostergren, JD Brown, GE Parks, GA Persson, P AF Ostergren, JD Brown, GE Parks, GA Persson, P TI Inorganic ligand effects on Pb(II) sorption to goethite (alpha-FeOOH) - II. Sulfate SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE Pb; sulfate; sorption; goethite; surface complexes; EXAFS; ATR-FTIR; bond valence ID X-RAY-ABSORPTION; BOND-VALENCE DETERMINATION; SURFACE FUNCTIONAL-GROUPS; OXIDE-SOLUTION INTERFACES; HYDROUS FERRIC-OXIDE; ANION ADSORPTION; IRON-OXIDES; SYNTHETIC GOETHITE; WATER INTERFACES; FORCE MICROSCOPY AB The effects of sulfate anions on the uptake of Pb(II) onto goethite were investigated at the molecular level using in situ Pb L-III-EXAFS and ATR-FTIR spectroscopies. Macroscopic uptake data show that Pb uptake can be enhanced by at least 30% at pH 5 in the presence of 3.16 mM sulfate and that sulfate uptake at pH 7 can be enhanced by more than a factor of 3 in the presence of 1.0 mM Pb. Consistent with behavior in sulfate-free systems, Pb(II) forms inner-sphere complexes sharing either corners or edges with Fe(O,OH)(6) octahedra under all conditions studied. The relative fraction of corner-sharing complexes is, however, significantly enhanced in the presence of sulfate at pH 5, 6, and 7 (all conditions studied) and additional sulfate species with Ca or lower point symmetry were noted in the presence of Pb by ATR-FTIR. Drawing on bond valence and structural constraints developed in J. D. Ostergren ef al. (2000, J. Colloid Interface Science 224, 000-000), these results indicate formation of Type A ternary complexes bonded to the surface through Pb that is bound as a bridging bidenate complex to two adjacent A-type (singly coordinated) surface oxygens (=Fe-O)(2)-Pb-OSO3). (C) 2000 Academic Press. C1 Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Umea Univ, Dept Inorgan Chem, S-90187 Umea, Sweden. RP Brown, GE (reprint author), Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. RI Persson, Per/D-7388-2012 OI Persson, Per/0000-0001-9172-3068 NR 57 TC 89 Z9 90 U1 6 U2 34 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD MAY 15 PY 2000 VL 225 IS 2 BP 483 EP 493 DI 10.1006/jcis.1999.6702 PG 11 WC Chemistry, Physical SC Chemistry GA 313EX UT WOS:000086988300028 ER PT J AU Bonhoeffer, S Mohri, H Ho, D Perelson, AS AF Bonhoeffer, S Mohri, H Ho, D Perelson, AS TI Quantification of cell turnover kinetics using 5-bromo-2 '-deoxyuridine SO JOURNAL OF IMMUNOLOGY LA English DT Article ID T-CELLS; DNA CONTENT; BROMODEOXYURIDINE; MEMORY; LYMPHOCYTES; INFECTION; RATES AB 5-Bromo-2'-deoxyuridine (BrdU) is frequently used to measure the turnover of cell populations in vivo. However, due to a lack of detailed mathematical models that describe the uptake and loss of BrdU in dividing cell populations, assessments of cell turnover kinetics have been largely qualitative rather than quantitative. In this study, we develop a mathematical framework for the analysis of BrdU-labeling experiments. We derive analytical expressions for the fraction of labeled cells within cell populations that are growing, declining, or at equilibrium. Fitting the analytical functions to data allows us to quantify the rates of cell proliferation and cell loss, as well as the rate of cell input from a source. We illustrate this far the BrdU labeling of T lymphocytes of uninfected and SIV-infected rhesus macaques. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Friedrich Miescher Inst, CH-4002 Basel, Switzerland. Rockefeller Univ, Aaron Diamond AIDS Res Ctr, New York, NY 10016 USA. RP Perelson, AS (reprint author), Univ Calif Los Alamos Natl Lab, MS-K710, Los Alamos, NM 87545 USA. RI Bonhoeffer, Sebastian/A-2735-2008 OI Bonhoeffer, Sebastian/0000-0001-8052-3925 FU NCRR NIH HHS [RR06555]; NIAID NIH HHS [AI28433, AI40387] NR 21 TC 73 Z9 73 U1 0 U2 0 PU AMER ASSOC IMMUNOLOGISTS PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-1767 J9 J IMMUNOL JI J. Immunol. PD MAY 15 PY 2000 VL 164 IS 10 BP 5049 EP 5054 PG 6 WC Immunology SC Immunology GA 312MW UT WOS:000086947900012 PM 10799860 ER PT J AU Lu, YP Dixon, AG Moser, WR Ma, YH Balachandran, U AF Lu, YP Dixon, AG Moser, WR Ma, YH Balachandran, U TI Oxygen-permeable dense membrane reactor for the oxidative coupling of methane SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE inorganic membranes; ceramic membranes; membrane reactors; mixed-conducting perovskite membranes; oxidative coupling of methane ID PEROVSKITE-TYPE OXIDES; HOLE MIXED CONDUCTOR; PERMEATION AB A perovskite material (BaCe0.8Gd0.2O3) in powder form, with both electronic and ionic conductivity, was synthesized by the ethylene glycol method. A dense membrane tube was fabricated using aplastic extrusion technique. The oxygen permeances of the dense membrane tube were measured as functions of temperature and oxygen partial pressure on the feed side. In the temperature range of 688-955 degrees C, the oxygen flux showed an approximately exponential dependence on temperature. The oxygen flux increased proportionally to the natural logarithm of the ratio of oxygen partial pressures across the membrane. Experimental results for the oxidative coupling of methane (OCM) to C-2 hydrocarbons, in the absence of additional catalyst, showed that this material has fairly good catalytic activity for the OCM reaction. The maximum yield to C-2 hydrocarbons that was obtained was 16%, which compares favorably to prior dense membrane studies. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Worcester Polytech Inst, Dept Chem Engn, Worcester, MA 01609 USA. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP Dixon, AG (reprint author), Worcester Polytech Inst, Dept Chem Engn, 100 Inst Rd, Worcester, MA 01609 USA. NR 32 TC 84 Z9 86 U1 5 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD MAY 15 PY 2000 VL 170 IS 1 BP 27 EP 34 DI 10.1016/S0376-7388(99)00354-3 PG 8 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 311DE UT WOS:000086868900004 ER PT J AU Burton, H AF Burton, H TI Atomic fragments: A daughter's questions. SO LIBRARY JOURNAL LA English DT Book Review C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. RP Burton, H (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU BOWKER MAGAZINE GROUP CAHNERS MAGAZINE DIVISION PI NEW YORK PA 249 W 17TH ST, NEW YORK, NY 10011 USA SN 0363-0277 J9 LIBR J JI Libr. J. PD MAY 15 PY 2000 VL 125 IS 9 BP 122 EP 122 PG 1 WC Information Science & Library Science SC Information Science & Library Science GA 312YR UT WOS:000086972000227 ER PT J AU Hsueh, CH Fuller, ER AF Hsueh, CH Fuller, ER TI Residual stresses in thermal barrier coatings: effects of interface asperity curvature/height and oxide thickness SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE residual stresses; coating; numerical simulations; analytical modeling ID OXIDATION-INDUCED STRESSES; SCALES; BEHAVIOR; SUBSTRATE; SYSTEM; FILMS AB The effects of curvature and height of the interface asperity on residual thermal stresses in a plasma-sprayed thermal barrier coating were numerically simulated. In the lip region of a convex asperity, the residual stress normal to the interface, sigma(y) is tensile in the ceramic top coat and increases with both curvature and height of the asperity. However. this residual tensile stress is lower for a periodic array of asperities than for an isolated asperity. The effects of thickness of the thermally grown oxide at the top coat-bond coat interface on residual thermal stresses were also numerically simulated. In the tip region of a convex asperity, sigma(y) in the ceramic top coat is tensile for a thin oxide but becomes compressive for a thick oxide. In the tip region of a concave asperity, sigma(y) in the ceramic top coat is compressive for a thin oxide and becomes less compressive for a thick oxide. The physical meaning of the above trend was qualitatively interpreted using an analytical model of three concentric circles. Published by Elsevier Science S.A. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 23 TC 58 Z9 62 U1 6 U2 22 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 15 PY 2000 VL 283 IS 1-2 BP 46 EP 55 DI 10.1016/S0921-5093(00)00743-7 PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 304HC UT WOS:000086476800006 ER PT J AU Nieh, TG Higashi, K Wadsworth, J AF Nieh, TG Higashi, K Wadsworth, J TI Effect of cell morphology on the compressive properties of open-cell aluminum foams SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE metallic foams; compression; tomography; cellular structure ID POROUS METALS AB The mechanical properties of open-cell 6101 aluminum foams with different densities ( similar to 5-10%) and morphologies (4-16 cells cm(-1)) were characterized in compression. It was found that density is the primary variable controlling the modulus and yield strength of foams. The effects of other variables such as cell size and shape were also studied. Whereas the cell size appears to have a negligible effect on the strength of foams, at a fixed density, the cell shape was shown to effect the strength of foams. In the present paper, theoretical models are offered to explain the differences in modulus and strength caused by the differences in cell shape and size. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Osaka Prefecture, Coll Engn, Dept Met & Mat Sci, Sakai, Osaka 5998531, Japan. RP Nieh, TG (reprint author), Univ Calif Lawrence Livermore Natl Lab, L-350,POB 808, Livermore, CA 94551 USA. RI Nieh, Tai-Gang/G-5912-2011 OI Nieh, Tai-Gang/0000-0002-2814-3746 NR 27 TC 146 Z9 159 U1 5 U2 36 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAY 15 PY 2000 VL 283 IS 1-2 BP 105 EP 110 DI 10.1016/S0921-5093(00)00623-7 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 304HC UT WOS:000086476800014 ER PT J AU Aschieri, P Brace, D Morariu, B Zumino, B AF Aschieri, P Brace, D Morariu, B Zumino, B TI Nonlinear self-duality in even dimensions SO NUCLEAR PHYSICS B LA English DT Article DE duality; Born-Infeld; supersymmetry ID STRING THEORY; SUPERSYMMETRY; ELECTRODYNAMICS; DUALISATION; SYMMETRIES; ROTATIONS; BREAKING; FIELDS AB We show that the Born-Infeld theory with n complex abelian gauge fields written in an auxiliary field formulation has a U(n, n) duality group. We conjecture the form of the Lagrangian obtained by eliminating the auxiliary fields and then introduce a new reality structure leading to a Born-Infeld theory with n real gauge fields and an Sp(2n, R) duality symmetry. The real and complex constructions are extended to arbitrary even dimensions. The maximal noncompact duality group is U(n, n) for complex fields. For real fields the duality group is Sp(2n, R) if half of the dimension of space-time is even and O(n, n) if it is odd. We also discuss duality under the maximal compact subgroup, which is the self-duality group of the theory obtained by fixing the expectation value of a scalar field. Supersymmetric versions of self-dual theories in four dimensions are also discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theoret Phys Grp, Berkeley, CA 94720 USA. RP Aschieri, P (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Aschieri, Paolo/J-2965-2012 NR 25 TC 23 Z9 23 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 15 PY 2000 VL 574 IS 1-2 BP 551 EP 570 DI 10.1016/S0550-3213(00)00019-5 PG 20 WC Physics, Particles & Fields SC Physics GA 317EJ UT WOS:000087212800021 ER PT J AU Biegert, J Diels, JC Milonni, PW AF Biegert, J Diels, JC Milonni, PW TI Bichromatic two-photon coherent excitation of sodium to provide a dual-wavelength guidestar SO OPTICS LETTERS LA English DT Article ID STAR AB A bichromatic sodium guide star based on two-photon coherent excitation followed by cascade emission is considered. Results of density matrix computations, including Doppler averaging, are presented for both a three-level model and the full hyperfine structure of the sodium 3S, 3P, and 4S levels. These results indicate that the proposed scheme for a bichromatic guide star is feasible. (C) 2000 Optical Society of America. C1 Univ New Mexico, Ctr High Technol Mat, Dept Phys & Astron, Albuquerque, NM 87131 USA. Univ Calif Los Alamos Natl Lab, Atom & Opt Theory Grp T4, Los Alamos, NM 87545 USA. RP Biegert, J (reprint author), Univ New Mexico, Ctr High Technol Mat, Dept Phys & Astron, Albuquerque, NM 87131 USA. RI Biegert, Jens/D-2243-2009 OI Biegert, Jens/0000-0002-7556-501X NR 14 TC 8 Z9 8 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAY 15 PY 2000 VL 25 IS 10 BP 683 EP 685 DI 10.1364/OL.25.000683 PG 3 WC Optics SC Optics GA 313GL UT WOS:000086991900001 PM 18064150 ER PT J AU del-Castiilo-Negrete, D AF del-Castiilo-Negrete, D TI Self-consistent dynamics in the single wave model SO PHYSICA A LA English DT Article; Proceedings Paper CT International Conference on Statistical Mechanics and Strongly Correlated Systems CY SEP 27-29, 1999 CL UNIV LA SAPIENZA, DEPT PHYS, ROME, ITALY SP Inst Nazl Fis Nucl, Inst Nazl Fis Mat, Gruppo Nazl Stutura Mat, Univ La Sapienza, Dipartimento Fis HO UNIV LA SAPIENZA, DEPT PHYS DE self-consistent dynamics; vortex dynamics; Hamiltonian chaos; mixing ID MARGINALLY STABLE PLASMAS; HAMILTONIAN-SYSTEMS; CHAOS; INSTABILITY; PERTURBATIONS; RELAXATION; EVOLUTION; SHEAR; BEAM AB A numerical study of self-consistent dynamics is presented in the context of the single-wave model (SWM). The SWM is a general mean-field model that describes the weakly nonlinear dynamics of marginally stable plasmas and fluids. Also, the SWM bears many similarities with models used to describe coupled oscillator systems. We construct integrable solutions of the SWM, and illustrate the concept of self-consistent resonant mixing by following numerically the evolution of perturbed integrable solutions. Using Fourier analysis we construct kinematic effective Hamiltonians. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP del-Castiilo-Negrete, D (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-15,MS-K717, Los Alamos, NM 87545 USA. OI del-Castillo-Negrete, Diego/0000-0001-7183-801X NR 15 TC 10 Z9 10 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD MAY 15 PY 2000 VL 280 IS 1-2 BP 10 EP 21 DI 10.1016/S0378-4371(99)00614-7 PG 12 WC Physics, Multidisciplinary SC Physics GA 313QK UT WOS:000087010200003 ER PT J AU Fernando, GW Sevilla, EH Cooper, BR AF Fernando, GW Sevilla, EH Cooper, BR TI Theoretical study of relativistic effects in the electronic structure of Pu SO PHYSICAL REVIEW B LA English DT Article ID ACTINIDE METALS AB We present a theoretical study of atomic and fee Pu related to the treatment of relativistic effects and equilibrium fee volume. The unusually large error in the theoretical fee volume has been recognized as a fundamental problem of metal physics. The commonly employed second variational treatment of the spin-orbit splitting in Pu is found to have a large (similar or equal to 25%) error in dealing with the 6p semicore states but not the 5f states of the Pu atom. In fee Pu, this error implies a corresponding nontrivial effect on various calculated equilibrium properties including the lattice volume. This points to the importance of correctly treating the localization of the 6p as well as the 5f electronic states in fee Pu and thereby recognizing the importance of specific relativistic effects for the 6p electrons that appear to have been ignored up to now. C1 Univ Connecticut, Dept Phys, Storrs, CT 06269 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Inst Fundamental Studies, Kandy, Sri Lanka. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. RP Fernando, GW (reprint author), Univ Connecticut, Dept Phys, U-46, Storrs, CT 06269 USA. NR 16 TC 5 Z9 5 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 12562 EP 12565 DI 10.1103/PhysRevB.61.12562 PG 4 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100004 ER PT J AU Hufner, S Yang, SH Mun, BS Fadley, CS Schafer, J Rotenberg, E Kevan, SD AF Hufner, S Yang, SH Mun, BS Fadley, CS Schafer, J Rotenberg, E Kevan, SD TI Observation of the two-hole satellite in Cr and Fe metal by resonant photoemission at the 2p absorption energy SO PHYSICAL REVIEW B LA English DT Article ID AUGER-SPECTROSCOPY; CO; SCATTERING; THRESHOLDS; RAMAN; NIO; MN AB Valence-band spectra of Cr and Fe metal were measured with photon energies around their respective 2p energies. An Auger signal is found to be superimposed on the valence-band photoemission signal for photon energies at and above the 2p absorption energy, but also for excitation energies down to similar to 4 eV below the 2p absorption energy. This is the radiationless resonance Raman (resonant Raman Auger) regime and gives rise to a signal that is equivalent, in terms of the final state, to the 6 eV satellite in Ni with energies at 3.5 eV below E-F in Cr and 3.2 eV below E-F in Fe. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Saarlandes, Fachbereich Phys, D-66041 Saarbrucken, Germany. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Univ Oregon, Dept Phys, Eugene, OR 97403 USA. RP Hufner, S (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RI Rotenberg, Eli/B-3700-2009; Kevan, Stephen/F-6415-2010; Mun, Bongjin /G-1701-2013 OI Rotenberg, Eli/0000-0002-3979-8844; Kevan, Stephen/0000-0002-4621-9142; NR 22 TC 45 Z9 46 U1 2 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 12582 EP 12585 DI 10.1103/PhysRevB.61.12582 PG 4 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100009 ER PT J AU Ridgway, MC Glover, CJ Yu, KM Foran, GJ Clerc, C Hansen, JL Larsen, AN AF Ridgway, MC Glover, CJ Yu, KM Foran, GJ Clerc, C Hansen, JL Larsen, AN TI Ion-dose-dependent microstructure in amorphous Ge SO PHYSICAL REVIEW B LA English DT Article ID ABSORPTION FINE-STRUCTURE; DISORDERED-SYSTEMS; EXAFS ANALYSIS; GERMANIUM; DAMAGE; SIMULATION AB Implantation-induced, microstructural modifications including increased bond length and non-Gaussian static disorder have been measured in amorphous Ge using extended x-ray absorption fine-structure spectroscopy. The evolution of the amorphous phase interatomic distance distribution as functions of ion dose and implant temperature demonstrates the influence of implantation conditions on amorphous phase structure. Results are attributed to increased fractions of three- and fivefold coordinated atoms as a means of accommodating implantation-induced point defects. C1 Australian Natl Univ, Dept Elect Mat Engn, Canberra, ACT 0200, Australia. Lawrence Berkeley Natl Lab, Mat Sci Div, Berkeley, CA 94701 USA. Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia. CNRS, Ctr Spectrometrie Nucl & Spectrometrie Masse, F-91405 Orsay, France. Aarhus Univ, Inst Phys & Astron, Aarhus, Denmark. RP Ridgway, MC (reprint author), Australian Natl Univ, Dept Elect Mat Engn, GPO Box 4, Canberra, ACT 0200, Australia. RI Yu, Kin Man/J-1399-2012; Ridgway, Mark/D-9626-2011 OI Yu, Kin Man/0000-0003-1350-9642; Ridgway, Mark/0000-0002-0642-0108 NR 14 TC 47 Z9 47 U1 2 U2 12 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 MAY 15 PY 2000 VL 61 IS 19 BP 12586 EP 12589 DI 10.1103/PhysRevB.61.12586 PG 4 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100010 ER PT J AU Hettler, MH Mukherjee, M Jarrell, M Krishnamurthy, HR AF Hettler, MH Mukherjee, M Jarrell, M Krishnamurthy, HR TI Dynamical cluster approximation: Nonlocal dynamics of correlated electron systems SO PHYSICAL REVIEW B LA English DT Article ID FALICOV-KIMBALL MODEL; SIMPLIFIED HUBBARD-MODEL; INFINITE DIMENSIONS; LATTICE; STATE; METALLIZATION; PRESSURE; FERMIONS; ENERGY; LIMIT AB We recently introduced the dynamical cluster approximation (DCA), a technique that includes short-ranged dynamical correlations in addition to the local dynamics of the dynamical mean-field approximation while preserving causality. The technique is based on an iterative self-consistency scheme on a finite-size periodic cluster. The dynamical mean-field approximation (exact result) is obtained by taking the cluster to a single site (the thermodynamic limit). Here, we provide details of our method, explicitly show that it is causal, systematic, Phi derivable, and that it becomes conserving as the cluster size increases. We demonstrate the DCA by applying it to a quantum Monte Carlo and exact enumeration study of the two-dimensional Falicov-Kimball model. The resulting spectral functions preserve causality, and the spectra and the charge-density-wave transition temperature converge quickly and systematically to the thermodynamic limit as the cluster size increases. C1 Univ Cincinnati, Dept Phys, Cincinnati, OH 45221 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Indian Inst Sci, Dept Phys, Bangalore 560012, Karnataka, India. RP Hettler, MH (reprint author), Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe, Germany. NR 33 TC 199 Z9 199 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 12739 EP 12756 DI 10.1103/PhysRevB.61.12739 PG 18 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100049 ER PT J AU Lippert, RA Sears, MP AF Lippert, RA Sears, MP TI Asymptotic convergence for iterative optimization in electronic structure SO PHYSICAL REVIEW B LA English DT Article ID SYSTEM-SIZE AB There have recently been a number of proposals for solving large electronic structure problems (local-density approximation, Hartree-Fock, and tight-binding methods) iteratively with a computational effort proportional to the size of the system. The effort needed to perform a single iteration in these schemes is well understood but the convergence rate has been an empirical matter. This paper will show that many of the proposed methods have a single underlying geometrical structure, which has a specific asymptotic convergence behavior, and that behavior can be understood in terms of some simple condition numbers based on the spectrum of the Hamiltonian. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Lippert, RA (reprint author), Sandia Natl Labs, MS 1110, Albuquerque, NM 87185 USA. EM ripper@cs.sandia.gov; mpsears@cs.sandia.gov NR 14 TC 4 Z9 4 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 12772 EP 12785 DI 10.1103/PhysRevB.61.12772 PG 14 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100052 ER PT J AU Herrera-Gomez, A Pianetta, P Marshall, D Nelson, E Spicer, WE AF Herrera-Gomez, A Pianetta, P Marshall, D Nelson, E Spicer, WE TI Geometrical structure of the 1/2-ML (2X1) and 1/3-ML (2X3) Ba/Si(001) interfaces SO PHYSICAL REVIEW B LA English DT Article ID RAY AB The adsorption site of Ba deposited on a clean Si(001) surface was measured using x-ray standing-wave spectroscopy (XSW). Two interfaces were considered: half a monolayer with a (2 X 1) surface symmetry, and a third of a monolayer with a (2 X 3) symmetry. Two (111)-like Bragg reflections, ((1) over bar (1) over bar 1) and ((1) over bar (1) over bar 1), were utilized in the XSW experiments. Using the structural results obtained from these two reflections, as well as symmetry arguments, it was possible to establish, in three dimensions, the coordinates of the adsorption site for the two interfaces considered. In both cases, Ba lies near the center of the square formed by four Si surface atoms, at a height close to the projection of the next ideal Si(001) plane. C1 CINVESTAV, Queretaro, Mexico. Stanford Synchrotron Radiat Lab, Stanford, CA 94305 USA. Motorola Inc, Phys Sci Res Labs, Tempe, AZ 85284 USA. RP Herrera-Gomez, A (reprint author), CINVESTAV, AP 101, Queretaro, Mexico. EM alberto@ciateq.mx NR 11 TC 35 Z9 35 U1 4 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 12988 EP 12991 DI 10.1103/PhysRevB.61.12988 PG 4 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100080 ER PT J AU Reboredo, FA Franceschetti, A Zunger, A AF Reboredo, FA Franceschetti, A Zunger, A TI Dark excitons due to direct Coulomb interactions in silicon quantum dots SO PHYSICAL REVIEW B LA English DT Article ID SI NANOCRYSTALS; POROUS SILICON; SEMICONDUCTOR NANOCRYSTALLITES; ELECTRONIC-PROPERTIES; OPTICAL-PROPERTIES; EXCHANGE ENERGIES; STOKES SHIFT; CONFINEMENT; STATES; CRYSTALLITES AB Electron-hole exchange interactions can lead to spin-forbidden ''dark'' excitons in direct-gap quantum dots. Here, we explore an alternative mechanism for creating optically forbidden excitons. In a large spherical quantum dot made of a diamond-structure semiconductor, the symmetry of the valence band maximum (VBM) is t(2). The symmetry of the conduction band minimum (CBM) in direct-gap material is a(1), but for indirect-gap systems the symmetry could be (depending on size) a(1), e, or t(2). In the latter cases, the resulting manifold of excitonic states contains several symmetries derived from the symmetries of the VBM and CBM (e.g., t(2) X t(2) = A(1) + E + T-1 + T-2 or t(2) X e = T-1 + T-2). Only the T-2 exciton is optically active or "bright," while the others A(1), E, and T-1 are "dark." The question is which is lower in energy, the dark or bright. Using pseudopotential calculations of the single-particle states of Si quantum dots and a direct evaluation of the screened electron-hole Coulomb interaction, we find that, when the CBM symmetry is t(2), the direct electron-hole Coulomb interaction lowers the energy of the dark excitons relative to the bright T-2 exciton. Thus, the lowest energy exciton is forbidden, even without an electron-hole exchange interaction. We find that our dark-bright excitonic splitting agrees well with experimental data of Calcott et al., Kovalev et al., and Brongersma et al. Our excitonic transition energies agree well with the recent experiment of Wolkin et al. In addition, and contradicting simplified models, we find that Coulomb correlations are more important for small dots than for intermediate sized ones. We describe the full excitonic spectrum of Si quantum dots by using a many-body expansion that includes both Coulomb and exchange electron hole terms. We present the predicted excitonic spectra. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Reboredo, FA (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI Reboredo, Fernando/B-8391-2009; Zunger, Alex/A-6733-2013 NR 49 TC 97 Z9 99 U1 1 U2 28 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 MAY 15 PY 2000 VL 61 IS 19 BP 13073 EP 13087 DI 10.1103/PhysRevB.61.13073 PG 15 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100094 ER PT J AU Sprung, M Larese, JZ AF Sprung, M Larese, JZ TI Adsorption isotherm studies of methyl chloride on MgO SO PHYSICAL REVIEW B LA English DT Article ID CH3CL MONOLAYERS; MAGNESIUM-OXIDE; GRAPHITE; SURFACE AB The wetting properties of methyl chloride (CH,CI) on MgO (100) surfaces have been investigated between 132 and 180 K using high-resolution adsorption isotherms. At low temperatures only one adsorption step is observed. At higher temperatures, i.e., T> 158.9 K, a second isotherm step appears, signaling the presence of a layering transition. Unlike adsorption behavior on graphite, however, there is no evidence of a low-to-high-density transition in the monolayer phase. In addition to the layering properties, the isothermal compressibility and isosteric heat of adsorption of the adsorbed films are calculated. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Sprung, M (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 21 TC 7 Z9 7 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 MAY 15 PY 2000 VL 61 IS 19 BP 13155 EP 13158 DI 10.1103/PhysRevB.61.13155 PG 4 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100105 ER PT J AU Wu, J Liu, BG Zhang, ZY Wang, EG AF Wu, J Liu, BG Zhang, ZY Wang, EG TI Reaction limited aggregation in surfactant-mediated epitaxy SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-BEAM EPITAXY; BY-LAYER GROWTH; SCANNING-TUNNELING-MICROSCOPY; THIN-FILM GROWTH; HOMOEPITAXIAL GROWTH; SELF-DIFFUSION; FRACTAL GROWTH; ISLAND DENSITY; METAL-SURFACES; DIMER EXCHANGE AB A theoretical model for reaction limited aggregation (RLA) is introduced to study the effect of a monolayer of surfactant on the formation of two-dimensional islands in heteroepitaxial and homoepitaxial growth. In this model the basic atomic processes are considered as follows. A stable island consists of the adatoms that have exchanged positions with the surfactant atoms beneath them. Movable active adatoms may (a) diffuse on the surfactant terrace, (b) exchange positions with the surfactant atoms beneath them and become island seeds (seed exchange), or (c) stick to stable islands and become stuck but still active adatoms. The rate-limiting step for the formation of a stable island is the seed exchange. Furthermore, a stuck but still active adatom must overcome a sizable potential-energy barrier to exchange positions with the surfactant atom beneath it and become a member of the stable island (aided exchange). The seed exchange process can occur with an adatom or collectively with an addimer. In the case of dimer exchange, the diffusing adatoms on the surfactant terrace can meet and (after exchanging) form stable dimers, which can then become island seeds. Systematic kinetic Monte Carlo simulations and rate-equation analysis of the model are carried out. The key finding of these simulations is that a counterintuitive fractal-to-compact island shape transition can be induced either by increasing deposition flux or by decreasing growth temperature. This major qualitative conclusion is valid for both the monomer and the dimer seed exchanges and for two different substrate lattices (square and triangular, respectively), although there are some quantitative differences in the flux and temperature dependence of the island density. The shape transition observed is contrary to the prediction of the classic diffusion-limited aggregation (DLA) theory, but in excellent qualitative agreement with recent experiments. In rationalizing the main finding, it is crucial to realize that the adatoms stuck to a stable island edge are still active and are surrounded by the surfactant atoms. Therefore, these stuck atoms cannot capture incoming adatoms before they join the island through aided exchange. As a result, an incoming adatom must on average hit the island many times before it finally finds a free edge site to stick to. This search is effectively equivalent to edge diffusion in DLA theory. The stuck adatoms thus act as shields which prevent other mobile adatoms from sticking to the stable islands. This shielding effect, determined by the aided exchange barrier and the density of the mobile adatoms, plays an essential role in inducing the above shape transition in surfactant-mediated epitaxial growth. C1 Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China. Chinese Acad Sci, Dept Condensed Matter Phys, Beijing 100080, Peoples R China. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys, Knoxville, TN 37996 USA. RP Wu, J (reprint author), Chinese Acad Sci, Inst Phys, POB 603, Beijing 100080, Peoples R China. OI Liu, Bang-Gui/0000-0002-6030-6680 NR 64 TC 28 Z9 31 U1 7 U2 13 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 13212 EP 13222 DI 10.1103/PhysRevB.61.13212 PG 11 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100113 ER PT J AU Chambers, SA Liang, Y Gao, Y AF Chambers, SA Liang, Y Gao, Y TI Noncommutative band offset at alpha-Cr2O3/alpha-Fe2O3(0001) heterojunctions SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-BEAM EPITAXY; PHOTOEMISSION; GROWTH; ALPHA-FE2O3; HETEROSTRUCTURES; FILMS; MBE AB We have measured the valence-band discontinuity at artificially structured, epitaxial heterojunctions of alpha-Cr2O3(0001) and alpha-Fe2O3(0001). Layered film structures of these two materials maintain the in-plane lattice parameter of alpha-Fe2O3(0001). Thus the alpha-Cr2O3(0001) layers are under a 2.4% tensile stress. A partial inward relaxation in alpha-Cr2O3(0001) layers along the c axis is also observed, revealing the presence of artifically structured epilayers with a cia ratio of 2.70, compared to 2.78 in bulk alpha-Cr2O3(0001). The valence-band offsets are -0.3 +/- 0.1 and + 0.7 +/- 0.1 eV when the top layer is Fe2O3 and Cr2O3, respectively. The noncommutativity in the band offset is not due to either anisotropic strain or quantum confinement, but rather appears to be due to a growth-sequence-dependent interface dipole. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Chambers, SA (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. NR 20 TC 45 Z9 45 U1 1 U2 16 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 19 BP 13223 EP 13229 DI 10.1103/PhysRevB.61.13223 PG 7 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100114 ER PT J AU Yu, KM Walukiewicz, W Shan, W Ager, JW Wu, J Haller, EE Geisz, JF Friedman, DJ Olson, JM AF Yu, KM Walukiewicz, W Shan, W Ager, JW Wu, J Haller, EE Geisz, JF Friedman, DJ Olson, JM TI Nitrogen-induced increase of the maximum electron concentration in group III-N-V alloys SO PHYSICAL REVIEW B LA English DT Article ID BAND-GAP SEMICONDUCTORS; NATIVE DEFECTS; COMPLEXES; ENERGY; GANAS; ZNSE; GAAS AB The maximum free-electron concentration is observed to increase dramatically with the nitrogen content x in heavily Se-doped Ga1-3xIn3xNxAs1-x (0 less than or equal to x<0.033) films. For example, an electron concentration of 7 x 10(19) cm(-3) was observed at x=0.033; a value more than 20 times larger than that observed in GaAs films grown under similar conditions. It is shown that the increase is caused by a combination of two effects: (1) a downward shift of the conduction band and (2) an increase of the electron effective mass caused by flattening of the conduction-band minimum. Both these effects are due to modifications td the conduction-band structure caused by an anticrossing interaction of a localized N state and the conduction band of the III-V host. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Div Sci Mat, Berkeley, CA 94720 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Div Sci Mat, Berkeley, CA 94720 USA. RI Yu, Kin Man/J-1399-2012; Wu, Junqiao/G-7840-2011 OI Yu, Kin Man/0000-0003-1350-9642; Wu, Junqiao/0000-0002-1498-0148 NR 20 TC 64 Z9 64 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 20 BP 13337 EP 13340 PG 4 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900005 ER PT J AU Klimov, VI Mikhailovsky, AA McBranch, DW Leatherdale, CA Bawendi, MG AF Klimov, VI Mikhailovsky, AA McBranch, DW Leatherdale, CA Bawendi, MG TI Mechanisms for intraband energy relaxation in semiconductor quantum dots: The role of electron-hole interactions SO PHYSICAL REVIEW B LA English DT Article ID NANOCRYSTALS; LUMINESCENCE; SPECTROSCOPY; TRANSITIONS; ABSORPTION; LASERS AB To evaluate the role of nonphonon energy relaxation mechanisms in quantum dots and in particular the role of electron-hole (e-h) interactions, we have studied femtosecond carrier dynamics in CdSe colloidal nanoparticles in which the e-h separation (coupling) is controlled using different types of surface ligands. In dots capped with hole accepting molecules, the e-h coupling is strongly reduced after the hole is transferred to a capping group. By re-exciting an electron within the conduction band at different stages of hole transfer and monitoring its relaxation back into the ground state, we observe a more than tenfold increase in the electron relaxation time (from 250 fs to 3 ps) after the completion of the hole transfer to the capping molecule. This strongly indicates that electron relaxation in quantum dots is dominated not by phonon emission but by the e-h energy transfer. C1 Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. MIT, Dept Chem, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RP Los Alamos Natl Lab, Chem Sci & Technol Div, CST-6,MS-J585, Los Alamos, NM 87545 USA. EM klimov@lanl.gov NR 22 TC 154 Z9 154 U1 5 U2 46 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 20 BP 13349 EP 13352 PG 4 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900008 ER PT J AU Lidorikis, E Sigalas, MM Economou, EN Soukoulis, CM AF Lidorikis, E Sigalas, MM Economou, EN Soukoulis, CM TI Gap deformation and classical wave localization in disordered two-dimensional photonic-band-gap materials SO PHYSICAL REVIEW B LA English DT Article ID ELECTROMAGNETIC-WAVES AB By using two ab initio numerical methods, we study the effects that disorder has on the spectral gaps and on wave localization in two-dimensional photonic-band-gap materials. We find that there are basically two different responses depending on the lattice realization (solid dielectric cylinders in air or vice versa), the wave polarization, and the particular form under which disorder is introduced. Two different pictures for the photonic states are employed, the ''nearly free" photon and the "strongly localized'' photon. These originate from the two different mechanisms responsible for the formation of the spectral gaps, i.e., multiple scattering and single scatterer resonances, and they qualitatively explain our results. C1 US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ Sci & Technol, Dept Phys & Astron, Ames, IA 50011 USA. FORTH, Res Ctr Crete, Heraklion 71110, Crete, Greece. Univ Crete, Dept Phys, Heraklion 71110, Crete, Greece. RP Lidorikis, E (reprint author), US DOE, Ames Lab, Ames, IA 50011 USA. RI Economou, Eleftherios /E-6374-2010; Soukoulis, Costas/A-5295-2008 NR 12 TC 69 Z9 69 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 20 BP 13458 EP 13464 DI 10.1103/PhysRevB.61.13458 PG 7 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900028 ER PT J AU Siders, JLW Trugman, SA Garzon, FH Houlton, RJ Taylor, AJ AF Siders, JLW Trugman, SA Garzon, FH Houlton, RJ Taylor, AJ TI Terahertz emission from YBa2Cu3O7-(delta) thin films via bulk electric-quadrupole-magnetic-dipole optical rectification SO PHYSICAL REVIEW B LA English DT Article ID SEMICONDUCTOR SURFACES; BEHAVIOR; PULSES AB We report the observation of terahertz emission from YBa2Cu3O7-delta thin films excited by 1.5-eV, 150-fs pulses in the absence of external electric or magnetic fields. This emission is characterized for optimally doped delta = 0 films and underdoped delta = 0.5 films, over a range of temperatures T, 4 K < T < 300 K, where the films change from superconductors to correlated metals. It exhibits a pronounced 4 phi dependence with respect to the azimuthal angle phi. We demonstrate that this emission is generated by optical rectification due to the bulk electric quadrupole and magnetic dipole source terms. A model of this emission, assuming that the nonlinearity results from transport of carriers with different masses and relaxation times in the three crystallographic directions, is consistent with the data. A fit of the data to this model yields values for the anisotropic masses and relaxation times in YBa2Cu3O7-delta thin films. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Taylor, AJ (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, MS K764, Los Alamos, NM 87545 USA. EM ttaylor@lanl.gov NR 14 TC 14 Z9 14 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 20 BP 13633 EP 13638 DI 10.1103/PhysRevB.61.13633 PG 6 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900045 ER PT J AU Scholes, GD Larsen, DS Fleming, GR Rumbles, G Burn, PL AF Scholes, GD Larsen, DS Fleming, GR Rumbles, G Burn, PL TI Origin of line broadening in the electronic absorption spectra of conjugated polymers: Three-pulse-echo studies of MEH-PPV in toluene SO PHYSICAL REVIEW B LA English DT Article ID NONLINEAR-OPTICAL RESPONSE; LONG POLYENE CHAINS; PHOTON-ECHO; SOLVATION DYNAMICS; SEMICONDUCTOR NANOSTRUCTURES; INTERCHAIN INTERACTIONS; CONDENSED PHASES; ENERGY-TRANSFER; PEAK SHIFT; SPECTROSCOPY AB Integrated three-pulse stimulated echo peak shift data are compared for N,N-bis-dimethylphenyl-1-2,4,6,8-perylenetetracarbonyl diamide and poly[2-(2'-ethylhexyloxy)-5-methoxy-1,4-phenylenevinylene] (MEH-PPV) in toluene solvent. These two molecules represent a model probe of solvation dynamics and a prototypical soluble, electroluminescent conjugated polymer, respectively. The results indicate that it is inappropriate to describe the linear absorption spectrum of MEH-PPV as being primarily inhomogeneously broadened. Conformational disorder along the polymer backbone gives rise to an ensemble of polyene electronic oscillators that are strongly coupled to each other. As a consequence, fluctuations in the electronic energy gap on a time-scale of 50-fs derive primarily from bath-mediated exciton scattering. The data reported here provide an explanation for the broad, structureless electronic absorption of MEH-PPV. This interpretation provides a valuable insight into the nature of the initial photoexcited state, and the efficient population of the emissive state. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ London Imperial Coll Sci Technol & Med, Dept Chem, Ctr Elect Mat & Devices, London SW7 2AY, England. Univ Oxford, Dyson Perrins Lab, Oxford OX1 3QY, England. RP Scholes, GD (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RI Burn, Paul/F-5347-2010; OI Rumbles, Garry/0000-0003-0776-1462 NR 63 TC 73 Z9 74 U1 0 U2 14 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 MAY 15 PY 2000 VL 61 IS 20 BP 13670 EP 13678 DI 10.1103/PhysRevB.61.13670 PG 9 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900050 ER PT J AU Cheong, HM Zhang, Y Mascarenhas, A Geisz, JF AF Cheong, HM Zhang, Y Mascarenhas, A Geisz, JF TI Nitrogen-induced levels in GaAs1-xNx studied with resonant Raman scattering SO PHYSICAL REVIEW B LA English DT Article ID ALLOYS AB Resonant Raman scattering is used to study the nature of the recently discovered nitrogen-induced level E+ located in the conduction band of GaAs1-xNx (0.001 less than or equal to x less than or equal to 0.022). Our data demonstrate that the E+ state is derived from the nitrogen-induced T-L mixing of the bulk GaAs states;and that it is no an isolated nitrogen impurity level. A broadening of the GaAs-like longitudinal-optical phonon-line and an enhancement of the transverse-optical phonon line is observed near resonance, which is interpreted as being due to resonance with strongly localized states. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Cheong, HM (reprint author), Sogang Univ, Dept Phys, Seoul 121742, South Korea. RI Cheong, Hyeonsik/D-7424-2012 OI Cheong, Hyeonsik/0000-0002-2347-4044 NR 16 TC 58 Z9 62 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 20 BP 13687 EP 13690 DI 10.1103/PhysRevB.61.13687 PG 4 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900052 ER PT J AU Riva, C Peeters, FM Varga, K AF Riva, C Peeters, FM Varga, K TI Excitons and charged excitons in semiconductor quantum wells SO PHYSICAL REVIEW B LA English DT Article ID HIGH MAGNETIC-FIELDS; GROUND-STATE ENERGY; TRANSITION ENERGIES; BINDING-ENERGY; D CENTERS; PHOTOLUMINESCENCE; LOCALIZATION; BIEXCITONS AB A variational calculation of the ground-stare energy of neutral excitons and of positively and negatively charged excitons (trions) confined in a single-quantum well is presented. We study the dependence of the correlation energy and of the binding energy on the well width and on the hole mass. The conditional probability distribution for positively and negatively charged excitons is obtained, providing information on the correlation and the charge distribution in the system. A comparison is made with available experimental data on trion binding energies in GaAs-, ZnSe-, and CdTe-based quantum well structures, which indicates that trions become localized with decreasing quantum well width. C1 Univ Instelling Antwerp, Dept Natuurkunde, B-2610 Wilrijk, Belgium. Argonne Natl Lab, Div Phys, Argonne, IL 60439 USA. RP Riva, C (reprint author), Univ Instelling Antwerp, Dept Natuurkunde, B-2610 Wilrijk, Belgium. EM riva@uia.ua.ac.be; peeters@uia.ua.ac.be RI Varga, Kalman/A-7102-2013; CMT, UAntwerpen Group/A-5523-2016 NR 32 TC 97 Z9 97 U1 0 U2 12 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 MAY 15 PY 2000 VL 61 IS 20 BP 13873 EP 13881 DI 10.1103/PhysRevB.61.13873 PG 9 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900075 ER PT J AU Smith, DL Kozhevnikov, M Lee, EY Narayanamurti, V AF Smith, DL Kozhevnikov, M Lee, EY Narayanamurti, V TI Scattering theory of ballistic-electron-emission microscopy at nonepitaxial interfaces SO PHYSICAL REVIEW B LA English DT Article ID BAND-STRUCTURE; ELASTIC-SCATTERING; CARRIER TRANSPORT; SPECTROSCOPY; HETEROSTRUCTURES; TRANSMITTANCE; RESOLUTION; AU/GAAS; OFFSETS; STATES AB We present an interface scattering model to describe ballistic-electron-emission microscopy (BEEM) at nonepitaxial metal/semiconductor interfaces. The model starts with a Hamiltonian consisting of the sum of two terms: one term, Ho, describes an ideal interface for which the interface parallel component of wave vector is a good quantum number, and the second term, delta H, describes interfacial scattering centers. The eigenstates of Ho consist of an incident and a reflected part in the metal and a transmitted part in the semiconductor. The three components of each eigenstate have the same interface parallel wave vector. Because tunneling preferentially weights forward-directed states, the interface parallel component of wave vector is small for the Ho eigenstates that are initially populated with high probability in BEEM. SH scatters electrons between the eigenstates of Ho. The scattering conserves energy, but not the interface parallel wave vector. In the final state of the scattering process, states with a large interface parallel wave vector can be occupied with reasonable probability. If scattering is weak, so that the parallel wave vector is nearly conserved, the calculated collector current into conduction-band valleys with zero parallel wave vector at the minimum, such as the Gamma valley for GaAs(100), is much larger than the calculated collector current into conduction-band valleys with a large parallel wave vector at the minimum, such as the L valleys for GaAs(100). However, if scattering is strong, the injected electron flux distribution is redistributed and valleys with zero interface transverse wave vector at their energy minimum are not preferentially weighted. Instead, the weighting varies as the density of final states for the scattering process so that, for example, the calculated L-channel collector current is much larger than the calculated Gamma-channel collector current for GaAs(100). Interfacial scattering reduces the overall magnitude of the calculated BEEM current near threshold for GaAs. We generalize the model to describe buried heterostructures and apply it to the Au/GaAs(100) interface and GaAs/AlxGa1-xAs heterostructures buried beneath this interface. Experimental results on these materials are presented and compared with the model. Strong scattering is required to describe the observed BEEM currents for Au/GaAs(100) and buried GaAs/AlxGa1-xAs heterostructures. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. RP Smith, DL (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 31 TC 23 Z9 23 U1 1 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 MAY 15 PY 2000 VL 61 IS 20 BP 13914 EP 13922 DI 10.1103/PhysRevB.61.13914 PG 9 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900077 ER PT J AU Soares, EA Bittencourt, C Nascimento, VB de Carvalho, VE de Castilho, CMC McConville, CF de Carvalho, AV Woodruff, DP AF Soares, EA Bittencourt, C Nascimento, VB de Carvalho, VE de Castilho, CMC McConville, CF de Carvalho, AV Woodruff, DP TI Structure determination of Ag(111)(root 3X root 3)R30 degrees-Sb by low-energy electron diffraction SO PHYSICAL REVIEW B LA English DT Article ID BY-LAYER GROWTH; ATOMIC-STRUCTURE; ION-SCATTERING; AG(111); SB; SURFACTANTS; ADSORPTION; CU(111); LEED; SI AB A quantitative structure determination of the Ag(111)(root 3 x root 3)R30 degrees-Sb surface has been performed using low energy electron diffraction. Six possible structural models were tested: Sb overlayers with four different adsorption sites and a substitutional alloy surface layer, with or without a stacking fault relative to the underlying substrate. The results clearly favor the faulted alloy surface model with all outermost layer Sb and Ag atoms occupying hcp hollow sites, in agreement with a recent x-ray diffraction study of this surface phase and both x-ray diffraction and medium energy ion scattering studies of the related Cu(111)(root 3 x root 3)R30 degrees-Sb surface. C1 UFMG, ICEx, Dept Fis, BR-30123970 Belo Horizonte, MG, Brazil. Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England. UFBA, Inst Fis, BR-40210340 Salvador, BA, Brazil. RP Soares, EA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA. EM edmar@mailman.lbl.gov RI de Castilho, Caio/B-9839-2013; Soares, Edmar/C-2303-2013; de Carvalho, Vagner/A-4583-2008 NR 23 TC 26 Z9 26 U1 2 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 2000 VL 61 IS 20 BP 13983 EP 13987 DI 10.1103/PhysRevB.61.13983 PG 5 WC Physics, Condensed Matter SC Physics GA 318LF UT WOS:000087284900086 ER PT J AU Cornwall, JM Kusenko, A AF Cornwall, JM Kusenko, A TI Baryon number nonconservation and phase transitions at preheating SO PHYSICAL REVIEW D LA English DT Article ID BARYOGENESIS; SUPERSYMMETRY; SUPERGRAVITY; INFLATION; BREAKING; VACUA; DECAY AB Certain inflation models undergo pre-heating, in which inflaton oscillations can drive parametric resonance instabilities. We discuss several phenomena stemming from such instabilities, especially in weak-scale models; generically, these involve energizing a resonant system so that it can evade tunneling by crossing barriers classically. One possibility is a spontaneous change of phase from a lower-energy vacuum state to one of higher energy, as exemplified by an asymmetric double-well potential with different masses in each well. If the lower well is in resonance with oscillations of the potential, a system can be driven resonantly to the upper well and stay there (except for tunneling) if the upper well is not resonant. Another example occurs in hybrid inflation models where the Higgs field is resonant; the Higgs oscillations can be transferred to electroweak (EW) gauge potentials, leading to rapid transitions over sphaleron barriers and consequent B + L violation. Given an appropriate CP-violating seed, we find that preheating can drive a time-varying condensate of Chern-Simons number over large spatial scales; this condensate evolves by oscillation as well as decay into modes with shorter spatial gradients, eventually ending up as a condensate of sphalerons. We study these examples numerically and to some extent analytically. The emphasis in the present paper is on the generic mechanisms, and not on specific preheating models; these will be discussed in a later paper. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Cornwall, JM (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. NR 28 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 MAY 15 PY 2000 VL 61 IS 10 AR 103510 DI 10.1103/PhysRevD.61.103510 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 314FT UT WOS:000087046300019 ER PT J AU Kruppa, AT Barmore, B Nazarewicz, W Vertse, T AF Kruppa, AT Barmore, B Nazarewicz, W Vertse, T TI Fine structure in the decay of deformed proton emitters: Nonadiabatic approach SO PHYSICAL REVIEW LETTERS LA English DT Article ID NUCLEI; ENERGIES AB The coupled-channel Schrodinger equation with outgoing wave boundary conditions is employed to study the fine structure seen in the proton decay of deformed even-N, odd-Z rare earth nuclei Eu-131 and Ho-141. Experimental lifetimes and proton-decay branching ratios are reproduced. Variations with the standard adiabatic theory are discussed. C1 Hungarian Acad Sci, Inst Nucl Res, H-4001 Debrecen, Hungary. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Warsaw, Inst Theoret Phys, PL-00681 Warsaw, Poland. RP Kruppa, AT (reprint author), Hungarian Acad Sci, Inst Nucl Res, POB 51, H-4001 Debrecen, Hungary. NR 29 TC 93 Z9 95 U1 2 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 MAY 15 PY 2000 VL 84 IS 20 BP 4549 EP 4552 DI 10.1103/PhysRevLett.84.4549 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100009 ER PT J AU Hoang, GT Bourdelle, C Garbet, X Antar, G Budny, RV Aniel, T Basiuk, V Becoulet, A Devynck, P Lasalle, J Martin, G Saint-Laurent, F AF Hoang, GT Bourdelle, C Garbet, X Antar, G Budny, RV Aniel, T Basiuk, V Becoulet, A Devynck, P Lasalle, J Martin, G Saint-Laurent, F CA Tore Supra Team TI Internal transport barrier with ion-cyclotron-resonance minority heating on Tore Supra SO PHYSICAL REVIEW LETTERS LA English DT Article ID REVERSED MAGNETIC SHEAR; IMPROVED CONFINEMENT; DISCHARGES; SIMULATIONS; PERFORMANCE; STABILITY; PLASMAS AB Recently, reversed magnetic shear operation was performed using only ion-cyclotron-resonance frequency minority heating (ICRH) during current ramp-up. A wide region of reversed magnetic shear has been obtained. For the first time, an electron internal transport barrier sustained by ICRH is observed, with a dramatical drop of density fluctuations. This barrier was maintained. on the current flat top, for about 2 a. C1 CEA Cadarache, EURATOM Assoc, Dept Rech Fus Controlee, F-13108 St Paul Durance, France. RP Hoang, GT (reprint author), Princeton Plasma Phys Lab, POB 451, Princeton, NJ 08543 USA. RI Artaud, Jean-Francois/G-8480-2011; ANIEL, Thierry/G-8734-2011; Dumont, Remi/D-3840-2009; Artaud, Jean-Francois/J-2068-2012 OI ANIEL, Thierry/0000-0002-2598-9551; NR 18 TC 39 Z9 39 U1 0 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 15 PY 2000 VL 84 IS 20 BP 4593 EP 4596 DI 10.1103/PhysRevLett.84.4593 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100020 ER PT J AU Choe, W Pecharsky, VK Pecharsky, AO Gschneidner, KA Young, VG Miller, GJ AF Choe, W Pecharsky, VK Pecharsky, AO Gschneidner, KA Young, VG Miller, GJ TI Making and breaking covalent bonds across the magnetic transition in the giant magnetocaloric material Gd-5(Si2Ge2) SO PHYSICAL REVIEW LETTERS LA English DT Article ID PHASE-TRANSITION; REFRIGERATION AB A temperature-dependent, single crystal x-ray diffraction study of the giant magnetocaloric material, Gd-5(Si2Ge2), across its Curie temperature (276 K) reveals that the simultaneous orthorhombic to monoclinic transition occurs by a shear mechanism in which the (Si, Ge)-(Si, Ge) dimers that are richer in Ge increase their distances by 0.859(3) if and lead to twinning. The structural transition changes the electronic structure, and provides an atomic-level model for the change in magnetic behavior with temperature in the Gd-5(SixGe1-x)(4). C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Mat Sci & Engn, Ames, IA 50011 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. RP Choe, W (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RI Choe, Wonyoung/H-8495-2012 OI Choe, Wonyoung/0000-0003-0957-1187 NR 20 TC 301 Z9 313 U1 6 U2 32 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 MAY 15 PY 2000 VL 84 IS 20 BP 4617 EP 4620 DI 10.1103/PhysRevLett.84.4617 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100026 ER PT J AU Fan, X Dickey, EC Eklund, PC Williams, KA Grigorian, L Buczko, R Pantelides, ST Pennycook, SJ AF Fan, X Dickey, EC Eklund, PC Williams, KA Grigorian, L Buczko, R Pantelides, ST Pennycook, SJ TI Atomic arrangement of iodine atoms inside single-walled carbon nanotubes SO PHYSICAL REVIEW LETTERS LA English DT Article ID RAMAN-SCATTERING; RESOLUTION; CRYSTALS; BUNDLES AB We report atomic resolution Z-contrast scanning transmission electron microscopy images that reveal the incorporation of I atoms in the form of helical chains inside single-walled carbon nanotubes. Density functional calculations and topological considerations provide a consistent interpretation of the experimental data. Charge transfer between the nanotube walls and the I chains is associated with the intercalation. C1 Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. RP Univ Kentucky, Dept Chem & Mat Engn, Lexington, KY 40506 USA. EM ecdickey@engr.uky.edu RI Dickey, Elizabeth/A-3368-2011 OI Dickey, Elizabeth/0000-0003-4005-7872 NR 22 TC 177 Z9 180 U1 3 U2 30 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 15 PY 2000 VL 84 IS 20 BP 4621 EP 4624 DI 10.1103/PhysRevLett.84.4621 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100027 ER PT J AU Qin, XR Swartzentruber, BS Lagally, MG AF Qin, XR Swartzentruber, BS Lagally, MG TI Scanning tunneling microscopy identification of atomic-scale intermixing on Si(100) at submonolayer Ge coverages SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTRONIC-STRUCTURES; SURFACE; SI(001); GROWTH; DIMER; SI; MORPHOLOGY; PHOTOEMISSION; INTERFACE; DIFFUSION AB The positions of Ge atoms intermixed in the Si(100) surface at very low concentration are identified using empty-state imaging in scanning tunneling microscopy. A measurable degree of place exchange occurs at temperatures as low as 330 K. Contrary to earlier conclusions, good differentiation between Si atoms and Ge atoms can be achieved by proper imaging conditions. C1 Univ Wisconsin, Madison, WI 53706 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Qin, XR (reprint author), Univ Wisconsin, Madison, WI 53706 USA. NR 28 TC 52 Z9 52 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 MAY 15 PY 2000 VL 84 IS 20 BP 4645 EP 4648 DI 10.1103/PhysRevLett.84.4645 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100033 ER PT J AU Barvosa-Carter, W Bracker, AS Culbertson, JC Nosho, BZ Shanabrook, BV Whitman, LJ Kim, H Modine, NA Kaxiras, E AF Barvosa-Carter, W Bracker, AS Culbertson, JC Nosho, BZ Shanabrook, BV Whitman, LJ Kim, H Modine, NA Kaxiras, E TI Structure of III-Sb(001) growth surfaces: The role of heterodimers SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; ENERGY ELECTRON-DIFFRACTION; MOLECULAR-BEAM EPITAXY; 001 SURFACES; RECONSTRUCTIONS; PSEUDOPOTENTIALS; PHOTOEMISSION; NUCLEATION; MODEL; ALSB AB We have determined the structure of AlSb and GaSb (001) surfaces prepared by molecular beam epitaxy under typical Sb-rich device growth conditions. Within the range of flux and temperature where the diffraction pattern is nominally (1 x 3), we find that there are actually three distinct, stable (4 x 3) surface reconstructions. The three structures differ from any previously proposed for these growth conditions, with two of the reconstructions incorporating mixed III-V dimers within the Sb surface layer. These heterodimers appear to play an important role in island nucleation and growth. C1 USN, Res Lab, Washington, DC 20375 USA. Harvard Univ, Cambridge, MA 02138 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP HRL Labs, Malibu, CA USA. EM wbc@hrl.com; Lloyd.Whitman@nrl.navy.mil RI Whitman, Lloyd/G-9320-2011 OI Whitman, Lloyd/0000-0002-3117-1174 NR 22 TC 62 Z9 62 U1 3 U2 9 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 15 PY 2000 VL 84 IS 20 BP 4649 EP 4652 DI 10.1103/PhysRevLett.84.4649 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100034 ER PT J AU Carmelo, JMP Peres, NMR Sacramento, PD AF Carmelo, JMP Peres, NMR Sacramento, PD TI Finite-frequency optical absorption in 1D conductors and Mott-Hubbard insulators SO PHYSICAL REVIEW LETTERS LA English DT Article ID MODEL; TRANSITION; EXPONENTS; WEIGHT; CHAIN; SALTS AB The frequency-dependent conductivity is studied for the one-dimensional Hubbard model, using a selection rule, the Bethe ansatz, and symmetries associated with conservation laws. For densities where the system is metallic the absorption spectrum has two contributions, a Drude peak at omega = 0 separated by a pseudogap from a broad absorption band whose lower edge is characterized by a nonclassical critical exponent. Our findings shed new light on the "far infrared puzzle" and other optical properties of metallic organic chain compounds. C1 Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. Univ Evora, Dept Phys, P-7002554 Evora, Portugal. IST, Dept Fis, P-1049001 Lisbon, Portugal. IST, CFIF, P-1049001 Lisbon, Portugal. RP Carmelo, JMP (reprint author), Univ Calif Los Alamos Natl Lab, CNLS, POB 1663, Los Alamos, NM 87545 USA. RI Peres, Nuno/B-9537-2008; Sacramento, Pedro D/H-4272-2012; OI Sacramento, Pedro D/0000-0002-8276-6485; Carmelo, Jose/0000-0001-5624-6294 NR 19 TC 25 Z9 25 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 MAY 15 PY 2000 VL 84 IS 20 BP 4673 EP 4676 DI 10.1103/PhysRevLett.84.4673 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100040 ER PT J AU Klumper, A Johnston, DC AF Klumper, A Johnston, DC TI Thermodynamics of the spin-1/2 antiferromagnetic uniform Heisenberg chain SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY; MODEL AB We present a new application of the traditional thermodynamic Bethe ansatz to the spin-1/2 antiferromagnetic uniform Heisenberg chain and derive exact nonlinear integral equations for just two functions describing the elementary excitations. By using this approach, the magnetic susceptibility chi and specific heat C versus temperature T are calculated to high accuracy for 5 x 10(-25), less than or equal to T/J less than or equal to 5. The chi(T) data agree very well at low T with the asymptotically exact theoretical low-T prediction of Lukyanov [Nucl. Phys. B522, 533 (1998)]. The unknown coefficients of the second and third lowest-order logarithmic correction terms in Lukyanov's theory for C(T) are estimated from the C(T) data. C1 Univ Cologne, Inst Theoret Phys, D-50937 Cologne, Germany. Univ Dortmund, Fachbereich Phys, D-44221 Dortmund, Germany. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Univ Cologne, Inst Theoret Phys, Zulpicher Str 77, D-50937 Cologne, Germany. NR 15 TC 81 Z9 82 U1 0 U2 10 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 15 PY 2000 VL 84 IS 20 BP 4701 EP 4704 DI 10.1103/PhysRevLett.84.4701 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100047 ER PT J AU Camley, RE Li, DQ AF Camley, RE Li, DQ TI Theoretical calculation of magnetic properties of ultrathin Fe films on Cu(100) SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANTIFERROMAGNETIC SUPERLATTICES; PHASE-TRANSITIONS; FE(001) FILMS; THIN-FILMS; CU(001); FE/CU(100); ANISOTROPY; OVERLAYERS; ENERGY; IRON AB The temperature dependence of the magnetization in fee Fe on Cu(100) is calculated using a self-consistent local mean-field theory. The model reproduces an experimental magnetization oscillation as a function of film thickness and supports a picture where the top two layers are ferromagnetically coupled, and the remaining layers are antiferromagnetically coupled. The origin of the puzzling linear temperature dependence in oscillation amplitude is understood as a "surface phenomena" of the antiferromagnetic layer at the Fe/Cu interface. Proximity effects between a thin antiferromagnet with a low Neel temperature and a neighboring ferromagnet with a higher Curie temperature are discussed. C1 Univ Colorado, Dept Phys, Colorado Springs, CO 80933 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Univ Colorado, Dept Phys, Colorado Springs, CO 80933 USA. NR 28 TC 35 Z9 35 U1 2 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 15 PY 2000 VL 84 IS 20 BP 4709 EP 4712 DI 10.1103/PhysRevLett.84.4709 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100049 ER PT J AU Naik, DS Peterson, CG White, AG Berglund, AJ Kwiat, PG AF Naik, DS Peterson, CG White, AG Berglund, AJ Kwiat, PG TI Entangled state quantum cryptography: Eavesdropping on the Ekert protocol SO PHYSICAL REVIEW LETTERS LA English DT Article ID KEY DISTRIBUTION; FREE-SPACE; BELL INEQUALITIES; VIOLATION; THEOREM; PHOTONS AB Using polarization-entangled photons from spontaneous parametric down-conversion, we have implemented Ekert's quantum cryptography protocol. The near-perfect correlations of the photons allow the sharing of a secret key between two parties. The presence of an eavesdropper is continually checked by measuring Bell's inequalities. We investigated several possible eavesdropper strategies, including pseudo-quantum-nondemolition measurements. In all cases, the eavesdropper's presence was readily apparent. We discuss a procedure to increase her detectability. C1 Univ Calif Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA. Univ Queensland, Dept Phys, Brisbane, Qld 4072, Australia. RP Kwiat, PG (reprint author), Univ Calif Los Alamos Natl Lab, Div Phys, P-23, Los Alamos, NM 87545 USA. RI White, Andrew/A-1088-2009; OI White, Andrew/0000-0001-9639-5200; Naik, Devang S./0000-0001-6005-5669 NR 39 TC 283 Z9 293 U1 1 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 MAY 15 PY 2000 VL 84 IS 20 BP 4733 EP 4736 DI 10.1103/PhysRevLett.84.4733 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100055 ER PT J AU Chertkov, M AF Chertkov, M TI Polymer stretching by turbulence SO PHYSICAL REVIEW LETTERS LA English DT Article ID PASSIVE SCALAR; VELOCITY-FIELD; FLOW; STATISTICS; ADVECTION AB The stretching of a polymer chain by a large-scale chaotic flow is considered. The steady state which emerges as a balance of the turbulent stretching and anharmonic resistance of the chain is quantitatively described, i.e., the dependency on the flow parameters (Lyapunov exponent statistics) and the chain characteristics (the number of beads and the interbead elastic potential) is made explicit. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. RP Chertkov, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, T-13, Los Alamos, NM 87545 USA. RI Chertkov, Michael/O-8828-2015 NR 26 TC 66 Z9 66 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 15 PY 2000 VL 84 IS 20 BP 4761 EP 4764 DI 10.1103/PhysRevLett.84.4761 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100062 ER PT J AU Lemoff, AV Lee, AP AF Lemoff, AV Lee, AP TI An AC magnetohydrodynamic micropump SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE magnetohydrodynamic; micropump; Lorentz force; microfluidics; micro total analysis system AB A microfluidic pump is presented using an AC magnetohydrodynamic (MHD) propulsion system in which the Lorentz force is used to propel an electrolytic solution along a microchannel etched in silicon. This micropump has no moving parts, produces a continuous (not pulsatile) flow and is compatible with solutions containing biological specimens. Theory, fabrication method and experimental results are described. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Lawrence Livermore Natl Lab, Ctr Microtechnol, Livermore, CA 94550 USA. RP Lemoff, AV (reprint author), Lawrence Livermore Natl Lab, Ctr Microtechnol, 7000 East Ave L-223, Livermore, CA 94550 USA. RI Lee, Abraham/E-7401-2011 NR 15 TC 213 Z9 222 U1 8 U2 35 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD MAY 15 PY 2000 VL 63 IS 3 BP 178 EP 185 DI 10.1016/S0925-4005(00)00355-5 PG 8 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 314NT UT WOS:000087062700007 ER PT J AU Walsh, MA Otwinowski, Z Perrakis, A Anderson, PM Joachimiak, A AF Walsh, MA Otwinowski, Z Perrakis, A Anderson, PM Joachimiak, A TI Structure of cyanase reveals that a novel dimeric and decameric arrangement of subunits is required for formation of the enzyme active site SO STRUCTURE LA English DT Article DE active site; cyanase; decamer structure; MAD phasing; monoanion and dianion inhibitors; synchrotron radiation ID ESCHERICHIA-COLI K-12; GENE ENCODING CYANASE; MACROMOLECULAR STRUCTURES; SULFHYDRYL-GROUP; CYSTEINE RESIDUES; REFINEMENT; PROTEINS; MAD; CRYSTALLOGRAPHY; IDENTIFICATION AB Background: Cyanase is an enzyme found in bacteria and plants that catalyzes the reaction of cyanate with bicarbonate to produce ammonia and carbon dioxide. In Escherichia coli, cyanase is induced from the cyn operon in response to extracellular cyanate. The enzyme is functionally active as a homodecamer of 17 kDa subunits, and displays half-site binding of substrates or substrate analogs. The enzyme shows no significant amino acid sequence homology with other proteins. Results: We have determined the crystal structure of cyanase at 1.65 Angstrom resolution using the multiwavelength anomalous diffraction (MAD) method. Cyanase crystals are triclinic and contain one homodecamer in the asymmetric unit. Selenomethionine-labeled protein offers 40 selenium atoms for use in phasing. Structures of cyanase with bound chloride or oxalate anions, inhibitors of the enzyme, allowed identification of the active site. Conclusions: The cyanase monomer is composed of two domains. The N-terminal domain shows structural similarity to the DNA-binding alpha-helix bundle motif. The C-terminal domain has an 'open fold' with no structural homology to other proteins. The subunits of cyanase are arranged in a novel manner both at the dimer and decamer level. The dimer structure reveals the C-terminal domains to be intertwined, and the decamer is formed by a pentamer of these dimers. The active site of the enzyme is located between dimers and is comprised of residues from four adjacent subunits of the homodecamer. The structural data allow a conceivable reaction mechanism to be proposed. C1 Argonne Natl Lab, Struct Biol Ctr, Biosci Div, Argonne, IL 60439 USA. Univ Texas, SW Med Sch, Dallas, TX USA. ILL, European Mol Biol Lab, F-38042 Grenoble, France. Univ Minnesota, Dept Biochem & Mol Biol, Duluth, MN 55812 USA. Northwestern Univ, Dept Biochem Mol Biol & Cell Biol, Evanston, IL 60208 USA. RP Joachimiak, A (reprint author), Argonne Natl Lab, Struct Biol Ctr, Biosci Div, 9700 S Cass Ave, Argonne, IL 60439 USA. EM andrzejj@anl.gov RI Otwinowski, Zbyszek/F-3665-2011; Perrakis, Anastassis/E-8704-2013; Walsh, Martin/I-1566-2013 OI Perrakis, Anastassis/0000-0002-1151-6227; Walsh, Martin/0000-0001-5683-1151 FU NIGMS NIH HHS [P50 GM062414, P50 GM062414-01] NR 64 TC 37 Z9 38 U1 0 U2 1 PU CELL PRESS PI CAMBRIDGE PA 600 TECHNOLOGY SQUARE, 5TH FLOOR, CAMBRIDGE, MA 02139 USA SN 0969-2126 J9 STRUCTURE JI Structure PD MAY 15 PY 2000 VL 8 IS 5 BP 505 EP 514 DI 10.1016/S0969-2126(00)00134-9 PG 10 WC Biochemistry & Molecular Biology; Biophysics; Cell Biology SC Biochemistry & Molecular Biology; Biophysics; Cell Biology GA 316AR UT WOS:000087145600008 PM 10801492 ER PT J AU Le Gall, B Tiercelin, JJ Richert, JP Gente, P Sturchio, NC Stead, D Le Turdu, C AF Le Gall, B Tiercelin, JJ Richert, JP Gente, P Sturchio, NC Stead, D Le Turdu, C TI A morphotectonic study of an extensional fault zone in a magma-rich rift: the Baringo Trachyte Fault System, central Kenya Rift SO TECTONOPHYSICS LA English DT Article DE Baringo Trachyte; basement control; central Kenya Rift; earthquake; extensional faulting; morphostructure ID REMOTE-SENSING APPROACH; EAST-AFRICA; SOUTHWEST ICELAND; GREGORY RIFT; LAKE BOGORIA; BASIN; EVOLUTION; VALLEY; TECTONICS; GEOMETRY AB The Baringo Trachyte Fault System is located within the central Kenya Rift and forms part of a N-S-trending linked extensional fault network. This fault system bounds to the west the 8 km deep Baringo Basin which itself lies within the axial valley of the central Kenya Rift. It mainly affects a middle Pleistocene trachytic dome (510 ka), the so-called Baringo Trachyte (BT), A morphotectonic study of the 10 km long BT master fault and associated downthrow geometries provides constraints on the evolution of a magma-type rift fault system from an initial stage of crack opening through to propagation. A model of radial fault growth is proposed in order to account for the longitudinal segmentation of the main fault escarpment from the median part to the tips. The small-scale half-graben geometry developed in the median high-strain zone is progressively accommodated laterally by both flexure and related narrow compensation grabens. The resulting crack swarms are well-developed at the free southern tip zone. Both the spatial distribution of rock-breaking products and their relations to the immediate hangingwall provide further evidence for this hypothesis. Well-developed screes and other gravity-driven structures (slumps) preferentially occur along the median part of the Baringo Trachyte Fault Escarpment, probably as earthquake-induced features. The hangingwall fault zone shows an asymmetrical triangular-shape with a maximum width of about half the length of the main scarp. This zone of maximum deformation and subsidence appears to be laterally controlled by two major, conjugate, transverse basement discontinuities lying with a conjugate geometry. Its internal architecture is dominated by antithetic westerly-dipping normal faults bounding discrete half-grabens, locally infilled by syn-tectonic volcaniclastics. Chronological data on hydrothermal silica filling open cracks on the BT footwall suggest that the master fault evolution occurred from 345 to 198 ka, as the possible result of at least four major normal faulting earthquakes. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Bretagne Occidentale, Inst Unic Europeen Mer, CNRS, UMR Domaines Ocean 6538, F-29280 Plouzane, France. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Exeter, Camborne Sch Mines, Redruth, Cornwall, England. Elf Petr Norge AS, N-4001 Stavanger, Norway. RP Le Gall, B (reprint author), Univ Bretagne Occidentale, Inst Unic Europeen Mer, CNRS, UMR Domaines Ocean 6538, Pl Nicolas Copernic, F-29280 Plouzane, France. RI Le Gall, Bernard/A-3633-2010 NR 67 TC 20 Z9 20 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD MAY 15 PY 2000 VL 320 IS 2 BP 87 EP 106 DI 10.1016/S0040-1951(00)00069-X PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 318FT UT WOS:000087273800001 ER PT J AU Sasaki, A Weber, ER Liliental-Weber, Z Ruvimov, S Washburn, J Nabetani, Y AF Sasaki, A Weber, ER Liliental-Weber, Z Ruvimov, S Washburn, J Nabetani, Y TI Transition thickness of semiconductor heteroepitaxy SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 3rd International Conference on Molecular Beam Epitaxy-Growth Physics and Technology (MBE-GPT 99) CY MAY 23-28, 1999 CL WARSAW, POLAND SP Polish Vacuum Soc, Polish Crystal Growth Soc, Inst Vacuum Technol, Polish Acad Sci, Inst Phys, Inst Electon Technol, State Comm Sci es DE MBE growth modes; transition thickness from 2D to 3D growth; thermodynamic approach to theory of epitaxial growth ID ENERGY ELECTRON-DIFFRACTION; ISLAND FORMATION; INP ISLANDS; GROWTH; INAS; GAAS; EQUILIBRIUM; MICROSCOPY; SUBSTRATE; DOTS AB In Stranski-Krastanov mode, the transition from two-dimensional growth to three-dimensional growth occurs at a certain thickness: a transition thickness. In subsequent growth, misfit dislocations are incorporated at the inter-face between the substrate and the epitaxially grown layer. This limited thickness for coherent growth is called: the critical thickness. An analytical equation for the transition thickness is derived by the thermodynamical approach in which strain energy and surface energy are taken into account. The three-dimensional island, often called a quantum dot, is stably formed, when the strain energy of the two-dimensional layer exceeds the sum of the relaxed strain energy and the excess surface energy of the three-dimensional island. The equation is applied to obtain the transition thickness of InAs/GaAs, InP/ GaP, and Ge/Si which fit fairly well with the experimental results. (C) 2000 Published by Elsevier Science S.A. All rights reserved. C1 Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Berkeley, CA USA. Kyoto Univ, Dept Elect Sci & Engn, Kyoto, Japan. RP Sasaki, A (reprint author), Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RI Liliental-Weber, Zuzanna/H-8006-2012 NR 14 TC 16 Z9 16 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAY 15 PY 2000 VL 367 IS 1-2 BP 277 EP 280 DI 10.1016/S0040-6090(00)00688-X PG 4 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 320QU UT WOS:000087412500045 ER PT J AU Gargas, ML Tyler, TR Sweeney, LM Corley, RA Weitz, KK Mast, TJ Paustenbach, DJ Hays, SM AF Gargas, ML Tyler, TR Sweeney, LM Corley, RA Weitz, KK Mast, TJ Paustenbach, DJ Hays, SM TI A toxicokinetic study of inhaled ethylene glycol monomethyl ether (2-ME) and validation of a physiologically based pharmacokinetic model for the pregnant rat and human SO TOXICOLOGY AND APPLIED PHARMACOLOGY LA English DT Article DE 2-methoxyethanol; 2-methoxyacetic acid; physiologically based pharmacokinetic (PBPK) model ID 2-METHOXYACETIC ACID; METHOXYACETIC ACID; DIMETHOXYETHYL PHTHALATE; CD-1 MICE; 2-METHOXYETHANOL; TERATOGENICITY; DISPOSITION; METABOLITE; METHOXYETHANOL; EXPOSURE AB Exposures to sufficiently high doses of ethylene glycol monomethyl ether (2-methoxyethanol, 2-ME) have been found to produce developmental effects in rodents and nonhuman primates. The acetic acid metabolite of 2-ME, 2-methoxyacetic acid (2-MAA), is the likely toxicant, and, as such, an understanding of the kinetics of 2-MAA is important when assessing the potential risks to humans associated with 2-ME. A previously described physiologically based pharmacokinetic (PBPK) model of 2-ME/2-MAA kinetics for rats exposed via oral or iv administration was extended and validated to inhalation exposures. Pregnant Sprague-Dawley rats were exposed for 5 days (gestation days 11-15), 6 h/day, to 2-ME vapor at 10 and 50 ppm. Validation consisted of comparing model output to maternal blood and fetal 2-ME and 2-MAA concentrations during and following 5 days of exposure (gestation days 11-15). These concentrations correspond to a known no observed effect level (NOEL) and a lowest observed effect level (LOEL) for developmental effects in rats. The rat PBPK model for 2-ME/2-MAA was scaled to humans and the model (without the pregnancy component) was used to predict data collected by other investigators on the kinetics of 2-MAA excretion in urine following exposures to 2-ME in human volunteers. The partially validated human model (with the pregnancy component) was used to predict equivalent human exposure concentrations based on 2-MAA dose measures (maximum blood concentration, C-max, and average daily area under the 2-MAA blood concentration curve, AUG, during pregnancy) that correspond to the concentrations measured at the rat NOEL and LOEL exposure concentrations. Using traditional PBPK scale-up techniques, it was calculated that pregnant women exposed for 8 h/day, 5 days/week, for the duration of pregnancy would need to be exposed to 12 or 60 ppm 2-ME to produce maternal 2-MAA blood concentrations (C-max or average daily AUG) equivalent to those in rats exposed to the NOEL (10 ppm) or LOEL (50 ppm), respectively. (C) 2000 Academic Press. C1 Serv McLaren Hart Inc, ChemRisk, Cleveland, OH USA. Union Carbide Corp, Danbury, CT USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Exponent Inc, Menlo Pk, CA USA. RP Gargas, ML (reprint author), Sapphire Grp, Twinsburg, OH 44087 USA. RI Sweeney, Lisa/K-5114-2012 OI Sweeney, Lisa/0000-0002-4672-7358 NR 43 TC 30 Z9 33 U1 0 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0041-008X J9 TOXICOL APPL PHARM JI Toxicol. Appl. Pharmacol. PD MAY 15 PY 2000 VL 165 IS 1 BP 53 EP 62 DI 10.1006/taap.2000.8928 PG 10 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 348RU UT WOS:000089000900005 PM 10814553 ER PT J AU Gargas, ML Tyler, TR Sweeney, LM Corley, RA Weitz, KK Mast, TJ Paustenbach, DJ Hays, SM AF Gargas, ML Tyler, TR Sweeney, LM Corley, RA Weitz, KK Mast, TJ Paustenbach, DJ Hays, SM TI A toxicokinetic study of inhaled ethylene glycol ethyl ether acetate and validation of a physiologically based pharmacokinetic model for rat and human SO TOXICOLOGY AND APPLIED PHARMACOLOGY LA English DT Article DE ethylene glycol monoethyl ether acetate (EGEEA); ethylene glycol monoethyl ether (EGEE); ethoxyacetic acid (EAA); physiologically based pharmacokinetic (PBPK) model ID EXPERIMENTAL HUMAN EXPOSURE; MONOETHYL ETHER; ETHOXYACETIC ACID; 2-METHOXYACETIC ACID; URINARY-EXCRETION; PREGNANT MOUSE; F344/N RATS; 2-ETHOXYETHANOL; DISPOSITION; METABOLITE AB The solvents ethylene glycol monoethyl ether acetate (EGEEA) and ethylene glycol monoethyl ether (EGEE), at sufficiently high doses, are known to be rodent developmental toxicants, exerting their toxic effects through the action of their metabolite 2-ethoxyacetic acid (2-EAA). Thus risks associated with exposure to these compounds are best evaluated based on a measure of the internal dose of 2-EAA. The goals of the work reported here were to develop physiologically based pharmacokinetic (PBPK) models of EGEEA and EGEE for pregnant rats and humans. These models were used to identify human exposure levels (ppm in air) equivalent to the rat no observed effect level (NOEL) and lowest observed effect level (LOEL) for developmental effects (Hanley ef al., 1984). We exposed pregnant Sprague-Dawley rats to concentrations of EGEEA corresponding to the NOEL and LOEL. Maternal blood, urine, and fetal tissue concentrations of EGEE and 2-EAA measured in these experiments were used to validate the rat EGEEA and EGEE models. Data collected by other researchers were used to validate the capabilities of the rodent EGEEA and EGEE models to predict the kinetics in humans. The models for estimating circulating blood concentrations of 2-EAA were considered valid based on the ability of the model to accurately predict 2-EAA concentrations in rat blood, urine, and fetal tissue. The human inhaled concentration equivalent to the rat NOEL for EGEEA (50 ppm) was predicted to be 25 ppm using the maternal blood average daily area under the curve (AUC) and 40 ppm using the maximum concentration achieved in maternal blood (C-max). The human inhaled concentration equivalent to the rat LOEL for EGEEA (100 ppm) was determined to be 55 ppm using the maternal blood average daily AUC and 80 ppm using the maternal blood C-max. (C) 2000 Academic Press. C1 Serv McLaren Hart Inc, ChemRisk, Cleveland, OH USA. Union Carbide Corp, Danbury, CT USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Exponent Inc, Menlo Pk, CA USA. RP Gargas, ML (reprint author), Sapphire Grp, Twinsburg, OH 44087 USA. RI Sweeney, Lisa/K-5114-2012 OI Sweeney, Lisa/0000-0002-4672-7358 NR 51 TC 23 Z9 25 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0041-008X J9 TOXICOL APPL PHARM JI Toxicol. Appl. Pharmacol. PD MAY 15 PY 2000 VL 165 IS 1 BP 63 EP 73 DI 10.1006/taap.2000.8927 PG 11 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 348RU UT WOS:000089000900006 PM 10814554 ER PT J AU Wilson, KB Hanson, PJ Baldocchi, DD AF Wilson, KB Hanson, PJ Baldocchi, DD TI Factors controlling evaporation and energy partitioning beneath a deciduous forest over an annual cycle SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE evaporation; forest floor; energy budget; litter water content; deciduous forest; eddy-covariance; ameriflux ID BROAD-LEAVED FOREST; SEASONAL-VARIATION; PINE FOREST; EVAPOTRANSPIRATION; CO2; EXCHANGE; TRANSPIRATION; CANOPY; FLOOR; MODEL AB The energy balance components were measured above the ground surface of a temperate deciduous forest over an annual cycle using the eddy covariance technique. Over a year, the net radiation at the forest floor was 21.5% of that above the canopy, but this proportion was not constant, primarily because of the distinct phenological stages separated by the emergence and senescence of leaves. The dominant response to seasonal changes in net radiation was through corresponding changes in the sensible heat flux, and both net radiation and sensible heat flux peaked just before leaf emergence. Evaporation at the forest floor was typically less than 0.5 mm per day, and unlike sensible heat flux, was not closely coupled to seasonal changes in net radiation. Instead, evaporation at the forest floor responded primarily to rapid changes in litter water content. Forest floor evaporation was limited by the water-holding capacity of litter, and when the atmospheric demand was large, the litter layer dried on the time scale of several hours. After this rapid period of drying, net radiation and sensible heat flux dominated the energy budget. When leaves were present during the growing season, the sensible and latent energy fluxes at the forest floor were less than 10% of the total canopy fluxes, and the mean Bowen ratio was similar to that above the canopy. However, during the dormant season, the controls of the energy budget at the forest floor largely determine the whole canopy fluxes. On an annual basis, the fluxes from the forest floor are roughly 15-22% of those above the canopy and the evaporation was 86 mm. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Calif Berkeley, Dept Environm Sci Policy & Management, Berkeley, CA 94720 USA. RP Wilson, KB (reprint author), NOAA, Atmospher Turbulence & Diffus Div, POB 2456, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011; Baldocchi, Dennis/A-1625-2009 OI Hanson, Paul J./0000-0001-7293-3561; Baldocchi, Dennis/0000-0003-3496-4919 NR 33 TC 81 Z9 97 U1 4 U2 34 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD MAY 12 PY 2000 VL 102 IS 2-3 BP 83 EP 103 DI 10.1016/S0168-1923(00)00124-6 PG 21 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 305NV UT WOS:000086547800002 ER PT J AU Tarczay, G Csaszar, AG Leininger, ML Klopper, W AF Tarczay, G Csaszar, AG Leininger, ML Klopper, W TI The barrier to linearity of hydrogen sulphide SO CHEMICAL PHYSICS LETTERS LA English DT Article ID POTENTIAL-ENERGY SURFACE; DIRECT PERTURBATION-THEORY; BORN-OPPENHEIMER APPROXIMATION; RELATIVISTIC HARTREE-FOCK; VIBRATION-ROTATION LEVELS; BASIS-SET CONVERGENCE; SYSTEMATIC SEQUENCES; WAVE-FUNCTIONS; FORCE-FIELD; WATER AB High-quality ab initio quantum chemical methods, including higher-order coupled cluster (CC) and many-body perturbation (MP) theory, as well as full configuration interaction (FCI) benchmarks, with basis sets ranging from [S/H] [4s3p1d/2s1p] to [9s8p7d5f4g3h2i/7s6p5d4f3g2h] have been employed to obtain the best technically possible value for the barrier to linearity of hydrogen sulphide. Following careful extrapolations of MP2, CCSD and CCSD(T) energies to the complete basis set (CBS) limit and inclusion of small corrections due to scalar relativistic terms, core polarization and core correlation effects, and the diagonal Born-Oppenheimer correction (DBOC), the final electronic (vibrationless) extrapolated barrier height of this study is 24423 +/- 75 cm(-1). (C) 2000 Elsevier Science B.V. All rights reserved. C1 Eotvos Lorand Univ, Dept Theoret Chem, H-1518 Budapest 112, Hungary. Sandia Natl Labs, Livermore, CA 94551 USA. Univ Utrecht, Debye Inst, Theoret Chem Grp, NL-3584 CH Utrecht, Netherlands. RP Csaszar, AG (reprint author), Eotvos Lorand Univ, Dept Theoret Chem, POB 32, H-1518 Budapest 112, Hungary. EM csaszar@para.chem.elte.hu RI Csaszar, Attila/A-5241-2009; Tarczay, Gyorgy/E-3549-2012; Klopper, Wim/I-3163-2014; Institute (DINS), Debye/G-7730-2014 OI Tarczay, Gyorgy/0000-0002-2345-1774; Klopper, Wim/0000-0002-5219-9328; NR 36 TC 30 Z9 30 U1 1 U2 6 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 MAY 12 PY 2000 VL 322 IS 1-2 BP 119 EP 128 DI 10.1016/S0009-2614(00)00407-3 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 314MH UT WOS:000087059500019 ER PT J AU Shalliker, RA Broyles, BS Guiochon, G AF Shalliker, RA Broyles, BS Guiochon, G TI Evaluation of the secondary consolidation of columns for liquid chromatography by ultrasonic irradiation SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE secondary consolidation; ultrasonic irradiation; packing procedures; bed consolidation ID DYNAMIC AXIAL-COMPRESSION; PACKING MATERIALS; RETENTION DATA; BAND PROFILES; PREPARATIVE COLUMNS; C-18 COLUMNS; REPRODUCIBILITY; VISUALIZATION; REPEATABILITY; BEDS AB The consolidation of packed analytical chromatography columns was carried out under ultrasonic irradiation. Columns were first packed using a conventional high pressure downward slurry method. Then, they were subjected to further bed consolidation in the presence of ultrasonic vibration. This process of further bed consolidation is referred to as secondary consolidation. Secondary consolidation was observed to occur more readily in solvents of low viscosity and at low flow-rates (low pressures). Column efficiency was not observed to be a factor affecting the process of secondary consolidation of the packed bed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. Univ Western Sydney, CBBR Fac Sci & Technol, Richmond, NSW 2753, Australia. RP Guiochon, G (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 25 TC 11 Z9 11 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 12 PY 2000 VL 878 IS 2 BP 153 EP 163 DI 10.1016/S0021-9673(00)00275-2 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 317UB UT WOS:000087244400001 PM 10866062 ER PT J AU Wong, SS Porter, MD AF Wong, SS Porter, MD TI Origin of the multiple voltammetric desorption waves of long-chain alkanethiolate monolayers chemisorbed on annealed gold electrodes SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE alkanethiolate monolayers; reductive desorption; gold electrodes ID SELF-ASSEMBLED MONOLAYERS; SCANNING-TUNNELING-MICROSCOPY; QUARTZ-CRYSTAL MICROBALANCE; AU(111) SINGLE-CRYSTAL; REDUCTIVE DESORPTION; ELECTROCHEMICAL DESORPTION; UNDERPOTENTIAL DEPOSITION; 3-MERCAPTOPROPIONIC ACID; CRYSTALLOGRAPHIC ORIENTATION; PHASE-TRANSITIONS AB This paper examines possible factors responsible for the voltammetric fine structure exhibited from the reductive desorption and oxidative redeposition of long-chain alkanethiolate monolayers on smooth gold electrodes. Results reveal that the fine structure is connected to the local order of the adlayer. This conclusion is based on a series of characterizations of monolayers formed from hexadecanethiol (HDT) and octadecanethiol (ODT) on annealed mica-supported gold (Au mica) and on template-stripped gold (TSG). For annealed Au mica, a pair of overlapping waves separated by 20-100 mV are found for both the desorption and the redeposition process. In contrast, the voltammetry of the TSG system exhibits a single wave for the two processes. Findings from morphological assessments (oxidative stripping of iodine, scanning tunneling microscopy, and underpotential metal deposition of lead) of the underlying substrates reveal that the differences in the voltammetry are connected to a subtle difference in the microscopic roughness of the two substrates. The morphological data indicate that the surfaces of annealed Au mica and of TSG are strongly (111)-terraced, but that the sizes of the (111) terraces at TSG are significantly smaller. As a consequence, the TSG surface has a higher density of steps. Since the adlayer domain size is ultimately limited by the microscopic topography of the substrate, the voltammetric differences observed for the two types of substrates are attributed to differences in the ordering of the adlayer. A description of the differences in the processes for the desorption and redeposition is proposed and is examined within the context of recent interpretations. (C) 2000 Elsevier Science S.A. All rights reserved. C1 US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RP Porter, MD (reprint author), US DOE, Ames Lab, Microanalyt Instrumentat Ctr, Ames, IA 50011 USA. NR 59 TC 74 Z9 75 U1 1 U2 8 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD MAY 12 PY 2000 VL 485 IS 2 BP 135 EP 143 DI 10.1016/S0022-0728(00)00106-6 PG 9 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 327YX UT WOS:000087823000005 ER PT J AU Schwartz, SE Buseck, PR AF Schwartz, SE Buseck, PR TI Atmospheric science - Absorbing phenomena SO SCIENCE LA English DT Editorial Material ID AEROSOL-PARTICLES; CLIMATE; PHYSICS C1 Brookhaven Natl Lab, Div Atmospher Sci, Upton, NY 11973 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Arizona State Univ, Dept Chem Biochem, Tempe, AZ 85287 USA. RP Schwartz, SE (reprint author), Brookhaven Natl Lab, Div Atmospher Sci, Upton, NY 11973 USA. RI Schwartz, Stephen/C-2729-2008 OI Schwartz, Stephen/0000-0001-6288-310X NR 21 TC 17 Z9 17 U1 1 U2 8 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 12 PY 2000 VL 288 IS 5468 BP 989 EP 990 DI 10.1126/science.288.5468.989 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 313EY UT WOS:000086988400026 ER PT J AU Eng, PJ Trainor, TP Brown, GE Waychunas, GA Newville, M Sutton, SR Rivers, ML AF Eng, PJ Trainor, TP Brown, GE Waychunas, GA Newville, M Sutton, SR Rivers, ML TI Structure of the hydrated alpha-Al2O3 (0001) surface SO SCIENCE LA English DT Article ID METAL-OXIDE SURFACES; ELECTRONIC-STRUCTURE; ALUMINA SURFACES; WATER; ADSORPTION; AL2O3; H2O; SPECTROSCOPY; SORPTION; CO(II) AB The physical and chemical properties of the hydrated alpha-Al2O3 (0001) surface are important for understanding the reactivity of natural and synthetic aluminum-containing oxides. The structure of this surface was determined in the presence of water vapor at 300 kelvin by crystal truncation rod diffraction at a third-generation synchrotron x-ray source. The fully hydrated surface is oxygen terminated, with a 53% contracted double Al Layer directly below. The structure is an intermediate between alpha-Al2O3 and gamma-Al(OH)(3), a fully hydroxylated form of alumina. A semiordered oxygen Layer about 2.3 angstroms above the terminal oxygen Layer is interpreted as adsorbed water. The clean alpha-Al2O3 (0001) surface, in contrast, is AL terminated and significantly relaxed relative to the bulk structure. These differences explain the different reactivities of the clean and hydroxylated surfaces. C1 Univ Chicago, Consortium Adv Radiat Sources, Chicago, IL 60637 USA. Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. RP Eng, PJ (reprint author), Univ Chicago, Consortium Adv Radiat Sources, Chicago, IL 60637 USA. NR 39 TC 347 Z9 347 U1 8 U2 111 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 12 PY 2000 VL 288 IS 5468 BP 1029 EP 1033 DI 10.1126/science.288.5468.1029 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 313EY UT WOS:000086988400031 ER PT J AU Ackerman, AS Toon, OB Stevens, DE Heymsfield, AJ Ramanathan, V Welton, EJ AF Ackerman, AS Toon, OB Stevens, DE Heymsfield, AJ Ramanathan, V Welton, EJ TI Reduction of tropical cloudiness by soot SO SCIENCE LA English DT Article ID MARINE BOUNDARY-LAYER; FRACTIONAL CLOUDINESS; INDIAN-OCEAN; CLOUDS; MODEL; STRATOCUMULUS; ALBEDO; MICROPHYSICS; SCATTERING; AEROSOLS AB Measurements and models show that enhanced aerosol concentrations can augment cloud albedo not only by increasing total droplet cross-sectional area, but also by reducing precipitation and thereby increasing cloud water content and cloud coverage. Aerosol pollution is expected to exert a net cooling influence on the global climate through these conventional mechanisms. Here, we demonstrate an opposite mechanism through which aerosols can reduce cloud cover and thus significantly offset aerosol-induced radiative cooling at the top of the atmosphere on a regional scale. In model simulations, the daytime clearing of trade cumulus is hastened and intensified by solar heating in dark haze las found over much of the northern Indian Ocean during the northeast monsoon). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Colorado, Boulder, CO 80309 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Natl Ctr Atmospher Res, Boulder, CO 80301 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Sci Syst & Applicat, Greenbelt, MD 20771 USA. RP Ackerman, AS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI Heymsfield, Andrew/E-7340-2011; Welton, Ellsworth/A-8362-2012; Ackerman, Andrew/D-4433-2012 OI Ackerman, Andrew/0000-0003-0254-6253 NR 40 TC 669 Z9 702 U1 15 U2 109 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 12 PY 2000 VL 288 IS 5468 BP 1042 EP 1047 DI 10.1126/science.288.5468.1042 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 313EY UT WOS:000086988400035 ER PT J AU Godfrey, A Hughes, DA AF Godfrey, A Hughes, DA TI Scaling of the spacing of deformation induced dislocation boundaries SO ACTA MATERIALIA LA English DT Article DE dislocations; scaling; modeling structural behavior; transmission electron microscopy (TEM); microstructural parameters ID MICROSTRUCTURE; ORIENTATION; ALUMINUM; SIZE AB Methods for determining the distribution of spacings between near-planar dislocation boundaries are discussed. Subsequently, distributions of spacings for these boundaries have been determined for both single crystal and polycrystal samples. Misorientations across the extended planar dislocation boundaries were also measured for the single crystal samples. The probability density distribution for spacings exhibits a scaling behavior of nearly identical form to that seen for the probability density distribution of misorientation angles across these boundaries. The scaling behavior of the spacing distributions persists over a very wide strain range (epsilon(nu M) = 0.2-epsilon(nu M) =4.5) for different materials and deformation conditions. The scaling behavior of the boundary spacings can be accounted for by simple geometric models allowing for either formation or coalescence of these walls. Published bq Elsevier Science Ltd oil behalf of Acta Metallurgica Inc. C1 Sandia Natl Labs, Ctr Mat & Engn Sci, Livermore, CA 94550 USA. RP Hughes, DA (reprint author), Sandia Natl Labs, Ctr Mat & Engn Sci, Livermore, CA 94550 USA. RI Godfrey, Andrew/G-4458-2010 OI Godfrey, Andrew/0000-0002-5496-0424 NR 24 TC 75 Z9 80 U1 2 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAY 11 PY 2000 VL 48 IS 8 BP 1897 EP 1905 DI 10.1016/S1359-6454(99)00474-7 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 315CA UT WOS:000087094000022 ER PT J AU Hugo, RC Hoagland, RG AF Hugo, RC Hoagland, RG TI The kinetics of gallium penetration into aluminum grain boundaries - In situ TEM observations and atomistic models SO ACTA MATERIALIA LA English DT Article DE liquid metal embrittlement; transmission electron microscopy; computer simulation ID EMBRITTLEMENT; SURFACES; DEFECTS; METALS AB The penetration behavior of gallium into aluminum grain boundaries was compared with Al grain boundary properties estimated from atomistic computer models. Penetration speeds in individual grain boundaries were measured in situ in the transmission electron microscope (TEM), and the observed Al grain boundaries were simulated using the embedded atom method (EAM). Penetration speeds were relatively slow in low angle grain boundaries and most low Sigma boundaries; however, for high Sigma boundaries, penetration speeds varied widely and were not correlated with rotation angle or coincidence site lattice (CSL) Sigma value. Atomistic computer models suggested that the presence of structural barriers in the grain boundary plane was an important factor in determining penetration speeds. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd AII rights reserved. C1 Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RP Los Alamos Natl Lab, Ctr Mat Sci, Los Alamos, NM 87545 USA. RI Hoagland, Richard/G-9821-2012 NR 24 TC 63 Z9 66 U1 3 U2 22 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD MAY 11 PY 2000 VL 48 IS 8 BP 1949 EP 1957 DI 10.1016/S1359-6454(99)00463-2 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 315CA UT WOS:000087094000027 ER PT J AU Arkin, A AF Arkin, A TI Regulatory motifs, dynamics and engineering principles of intracellular networks SO FASEB JOURNAL LA English DT Meeting Abstract C1 Univ Calif Berkeley, Dept Bioengn, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Phys Biosci Div, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RI Arkin, Adam/A-6751-2008 OI Arkin, Adam/0000-0002-4999-2931 NR 0 TC 1 Z9 1 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAY 11 PY 2000 VL 14 IS 8 MA 15 BP A1313 EP A1313 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 313NH UT WOS:000087005400044 ER PT J AU Malkowski, MG Ginell, S Smith, WL Garavito, RM AF Malkowski, MG Ginell, S Smith, WL Garavito, RM TI Mechanistic implications inferred from the structure of Prostaglandin Endoperoxide H Synthase-1 complexed with arachidonic acid. SO FASEB JOURNAL LA English DT Meeting Abstract C1 Michigan State Univ, Dept Biochem, E Lansing, MI 48824 USA. Argonne Natl Lab, Struct Biol Ctr, Argonne, IL 60439 USA. RI Malkowski, Michael/G-4939-2011 OI Malkowski, Michael/0000-0003-1025-0014 NR 0 TC 0 Z9 0 U1 0 U2 1 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAY 11 PY 2000 VL 14 IS 8 MA 796 BP A1450 EP A1450 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 313NH UT WOS:000087005400828 ER PT J AU Marcol, CP Tsuruta, H Kantrowitz, ER AF Marcol, CP Tsuruta, H Kantrowitz, ER TI A concerted mechanism for the allosteric transition of E-coli aspartate transcarbamoylase SO FASEB JOURNAL LA English DT Meeting Abstract C1 Dept Chem, Chestnut Hill, MA 02467 USA. Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAY 11 PY 2000 VL 14 IS 8 MA 1225 BP A1526 EP A1526 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 313NH UT WOS:000087005401256 ER PT J AU Schlichting, I AF Schlichting, I TI A structural walk along the reaction cycle of cytochrome P450(cam). SO FASEB JOURNAL LA English DT Meeting Abstract C1 Max Planck Inst, Dortmund, Germany. Univ Calif Los Alamos Natl Lab, Biophys Grp, Los Alamos, NM 87544 USA. Brookhaven Natl Lab, Dept Biol, Upton, NY 11973 USA. Brandeis Univ, Rosenstiel Ctr, Waltham, MA 02254 USA. Univ Illinois, Dept Biochem, Chicago, IL 60680 USA. Univ Illinois, Beckman Inst Adv Sci & Technol, Chicago, IL 60680 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAY 11 PY 2000 VL 14 IS 8 MA C13 BP A1307 EP A1307 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 313NH UT WOS:000087005400013 ER PT J AU Zangar, RC Okita, JR Kim, HS Edwards, RJ Okita, RT AF Zangar, RC Okita, JR Kim, HS Edwards, RJ Okita, RT TI Induction of a microsomal ubiquitin ligase by in vivo nicardipine treatment SO FASEB JOURNAL LA English DT Meeting Abstract C1 Pacific NW Lab, Richland, WA 99352 USA. Washington State Univ, Pullman, WA 99164 USA. Detroit R&D Inc, Detroit, MI USA. Univ London Imperial Coll Sci Technol & Med, Sch Med, London, England. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAY 11 PY 2000 VL 14 IS 8 MA 132 BP A1333 EP A1333 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 313NH UT WOS:000087005400163 ER PT J AU Dexheimer, SL Van Pelt, AD Brozik, JA Swanson, BI AF Dexheimer, SL Van Pelt, AD Brozik, JA Swanson, BI TI Ultrafast vibrational dynamics in a quasi-one-dimensional system: Femtosecond impulsive excitation of the PtBr(ethylenediamine) mixed-valence linear chain complex SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID NONLINEAR LATTICE-RELAXATION; CHARGE-TRANSFER EXCITATION; METAL-COMPLEXES; STIMULATED SCATTERING; GROUND-STATE; SPECTROSCOPY; BACTERIORHODOPSIN; LASER AB We have used femtosecond impulsive excitation to time-resolve the vibrational motions following the excitation of the optical intervalence charge transfer transition in a quasi-one-dimensional molecular solid, the mixed-valence metal-halide linear chain complex [Pt(en)(2)][Pt(en)(2)Br-2].(PF6)(4) (en = ethylenediamine, C2H8N2) Wavelength-resolved measurements reveal an induced absorption signal assigned to the formation of the self-trapped exciton that is strongly modulated by vibrational wavepacket oscillations originating on both the ground and excited electronic states. The ground-state response, which includes the fundamental chain axis symmetric stretch frequency and its harmonics, is discussed in terms of resonantly enhanced impulsive stimulated Raman excitation of a strongly coupled electron-phonon system. C1 Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Dexheimer, SL (reprint author), Washington State Univ, Dept Phys, Pullman, WA 99164 USA. NR 18 TC 18 Z9 18 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 11 PY 2000 VL 104 IS 18 BP 4308 EP 4313 DI 10.1021/jp993859f PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313MH UT WOS:000087003100023 ER PT J AU Vasenkov, S Frei, H AF Vasenkov, S Frei, H TI Time-resolved study of acetyl radical in zeolite NaY by step-scan FT-IR spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER FLASH-PHOTOLYSIS; AB-INITIO PREDICTION; DIFFUSE-REFLECTANCE; INTRAZEOLITE PHOTOCHEMISTRY; DIPHENYLMETHYL RADICALS; FRIES REARRANGEMENT; 1-NAPHTHYL ACETATE; INFRARED-SPECTRA; ION-PAIRS; CATION AB Step-scan FT-infrared spectroscopy of l-naphthyl acetate and pinacolone photodissociation in zeolite NaY revealed a transient at 2125 cm(-1) assigned to acetyl radical. Comparison of the intensities of transient and final product absorptions, 2-acetyl-1-naphthol in the case of naphthyl acetate and acetaldehyde for pinacolone, indicates that the acetyl radical represents the main, and probably only, reaction channel. The decay of the radical at room temperature is best described by a single-exponential law with a lifetime of 71 +/- 15 mu s (1-napthyl acetate) and 315 +/- 30 mu s (pinacolone). This constitutes the first detection and kinetic study of a small transient radical in a zeolite. The kinetic result is interpreted in terms of complete separation of the photogenerated pairs from the parent supercage, followed by random walks in subspaces of the zeolite lattice imposed by the much less mobile precursor molecules. These force the geminate radicals to react and thereby contribute to the high selectivity of these photoreactions. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Mailstop Calvin Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RP Frei, H (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Mailstop Calvin Lab, Phys Biosci Div, Berkeley, CA 94720 USA. RI Lee, Yuan-Pern/F-7938-2012 OI Lee, Yuan-Pern/0000-0001-6418-7378 NR 52 TC 26 Z9 26 U1 0 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 11 PY 2000 VL 104 IS 18 BP 4327 EP 4332 DI 10.1021/jp994366d PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313MH UT WOS:000087003100026 ER PT J AU van de Lagemaat, J Frank, AJ AF van de Lagemaat, J Frank, AJ TI Effect of the surface-state distribution on electron transport in dye-sensitized TiO2 solar cells: Nonlinear electron-transport kinetics SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID MODULATED PHOTOCURRENT SPECTROSCOPY; NANOCRYSTALLINE AB Analytical expressions describing electron transport in dye-sensitized nanocrystalline TiO2 solar cells are derived and verified by intensity-modulated photocurrent spectroscopy measurements. An exponential distribution of surface states can account for the observed power law dependence of the electron-transport rate on the electron population, Use of an effective electron diffusion coefficient to describe the electron transport kinetics is found to be inadequate. A slope of 69 meV is inferred for the surface-state distribution curve. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. RP van de Lagemaat, J (reprint author), Natl Renewable Energy Lab, Golden, CO 80401 USA. RI van de Lagemaat, Jao/J-9431-2012 NR 16 TC 200 Z9 200 U1 1 U2 28 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 11 PY 2000 VL 104 IS 18 BP 4292 EP 4294 DI 10.1021/jp000836o PG 3 WC Chemistry, Physical SC Chemistry GA 313MM UT WOS:000087003500004 ER PT J AU Balasubramanian, M Melendres, CA Mini, S AF Balasubramanian, M Melendres, CA Mini, S TI X-ray absorption spectroscopy studies of the local atomic and electronic structure of iron incorporated into electrodeposited hydrous nickel oxide films SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID FINE-STRUCTURE; IN-SITU; ALKALINE ELECTROLYTES; MULTIPLE-SCATTERING; METAL-IONS; HYDROXIDES; SPECTRA; EXAFS; EDGE; OXYHYDROXIDES AB We have utilized X-ray absorption fine structure (XAFS) spectroscopy to investigate the local atomic and electronic structure of iron incorporated into electrodeposited nickel hydroxide films. We found that cathodic codeposition from a solution containing Fe(II) and Ni(II) ions results in iron occupying Ni lattice sites in CL-Ni(OH)(2). The X-ray absorption near edge structure (XANES) shows that Fe is present as Fe(III) ions in the cathodically codeposited film. Analysis of the extended X-ray absorption fine structure (EXAFS) shows that Fe is coordinated to oxygen at similar to 2.00 Angstrom and to Ni at similar to 3.11 Angstrom. This Fe-O bond length is smaller than the Fe(II)-O bond distance found in Fe(OH)(2) (similar to 2.10 Angstrom) but is in good agreement with the average Fe(III)-O bond distance found in FeOOH(alpha, gamma). The Fe-Ni bond distance is in agreement with that of the Ni(II)-Ni(II) bond distance found in alpha-Ni(OH)(2). Moreover, the radial structure function (RSF) around Fe shows a distinct peak at similar to 5.8 Angstrom, which is a fingerprint of the brucite (CI-Ni(OH)(2)) structure. On anodic oxidation of the codeposited film in KOH, we found that the Fe ions occupied Ni lattice sites in gamma-NiOOH. The XANES shows that the Fe edge shifts to higher energy values, indicating an increase in the oxidation state of Fe on charging. Analysis of the EXAFS data shows that Fe is coordinated to oxygen at similar to 1.94 Angstrom and to Ni at similar to 2.84 Angstrom. The latter value is in good agreement with the Ni(IV)-Ni(IV) bond length found in gamma-NiOOH. The RSF around Fe in the oxidized film shows a distinct peak at similar to 5.4 Angstrom, just as in the RSF of Ni in gamma-NiOOH. The Fe-O bond distance of similar to 1.94 Angstrom is in good agreement with the Fe(IV)-O bond distance found in SrFeO3. Our results strongly suggest that the Fe ions in the oxidized film is nominally tetravalent but with the Fe-O bond possessing a high degree of covalency. C1 Argonne Natl Lab, Div Chem Technol, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. RP Brookhaven Natl Lab, Bldg 480, Upton, NY 11973 USA. EM bmali@bnl.gov NR 42 TC 27 Z9 28 U1 4 U2 35 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 11 PY 2000 VL 104 IS 18 BP 4300 EP 4306 DI 10.1021/jp9921710 PG 7 WC Chemistry, Physical SC Chemistry GA 313MM UT WOS:000087003500006 ER PT J AU Dang, LX Feller, D AF Dang, LX Feller, D TI Molecular dynamics study of water-benzene interactions at the liquid/vapor interface of water SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID BASIS-SETS; SIMULATION; CLUSTERS; HYDROGEN AB The free energy profile of the transport of a benzene molecule across the liquid/vapor interface of water was investigated using molecular dynamics techniques. A large free energy minimum was found near the Gibbs dividing surface. At this free energy minimum, which is an indication of surface activity, the benzene molecule lies parallel to the surface and has an adsorption free energy of about -4 kcal/mol. In addition, there is a free energy barrier to passage from the bulk solution to the surface-adsorbed site. The hydration free energy estimated from the difference between gas-phase and liquid-phase free energies is about -0.1 +/- 0.4 kcal/mol, a value that agrees well with the corresponding experimental measurement of -0.767 kcal/mol. The results described in this paper demonstrate the validity of our approach, as well as the quality of our potential energy surfaces. C1 Pacific NW Lab, Richland, WA 99352 USA. RP Dang, LX (reprint author), Pacific NW Lab, POB 999,Mail Stop K8-91, Richland, WA 99352 USA. NR 26 TC 37 Z9 37 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 11 PY 2000 VL 104 IS 18 BP 4403 EP 4407 DI 10.1021/jp000054v PG 5 WC Chemistry, Physical SC Chemistry GA 313MM UT WOS:000087003500018 ER PT J AU Tretiak, S Middleton, C Chernyak, V Mukamel, S AF Tretiak, S Middleton, C Chernyak, V Mukamel, S TI Exciton Hamiltonian for the bacteriochlorophyll system in the LH2 antenna complex of purple bacteria SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID LIGHT-HARVESTING COMPLEX; RHODOPSEUDOMONAS-ACIDOPHILA STRAIN-10050; DIFFERENTIAL-OVERLAP TECHNIQUE; FEMTOSECOND ENERGY-TRANSFER; PUMP-PROBE SPECTROSCOPY; REAL-SPACE ANALYSIS; RHODOBACTER-SPHAEROIDES; ELECTRONIC EXCITATIONS; OPTICAL-EXCITATIONS; PHENYLACETYLENE DENDRIMERS AB An effective Frenkel-exciton Hamiltonian for the LH2 photosynthetic complex from Rhodospirillum molischianum is calculated using the collective electronic oscillator (CEO) approach combined with the crystal structure. The absorption spectra of the various bacteriochlorophyll aggregates forming the complex are computed using the CEO. Each electronic transition is further analyzed in terms of its characteristic electron-hole motions in real space. Using a two-dimensional representation of the underlying transition density matrices, we identify localized and delocalized electronic transitions, test the applicability of the exciton model, and compute interchromophore electronic couplings. Forster energy-transfer hopping time scales within B800 and from the B800 to the B850 system, obtained using the computed coupling constants, are in excellent agreement with experiment. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Rochester, Dept Chem, Rochester, NY 14627 USA. RP Tretiak, S (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RI Middleton, Chris/A-6365-2008; Tretiak, Sergei/B-5556-2009; Chernyak, Vladimir/F-5842-2016 OI Middleton, Chris/0000-0002-3518-9777; Tretiak, Sergei/0000-0001-5547-3647; Chernyak, Vladimir/0000-0003-4389-4238 NR 71 TC 67 Z9 68 U1 1 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 11 PY 2000 VL 104 IS 18 BP 4519 EP 4528 DI 10.1021/jp9939930 PG 10 WC Chemistry, Physical SC Chemistry GA 313MM UT WOS:000087003500032 ER PT J AU Frank, HA Bautista, JA Josue, J Pendon, Z Hiller, RG Sharples, FP Gosztola, D Wasielewski, MR AF Frank, HA Bautista, JA Josue, J Pendon, Z Hiller, RG Sharples, FP Gosztola, D Wasielewski, MR TI Effect of the solvent environment on the spectroscopic properties and dynamics of the lowest excited states of carotenoids SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CHLOROPHYLL-A-PROTEIN; EXCITATION-ENERGY TRANSFER; AMPHIDINIUM-CARTERAE; STARK SPECTROSCOPY; PERIDININ; PHOTOSYNTHESIS; COMPLEXES; POLYENES; SINGLET; SPHEROIDENE AB The spectroscopic properties and dynamics of the lowest excited singlet states of peridinin, fucoxanthin, neoxanthin, uriolide acetate, spheroidene, and spheroidenone in several different solvents have been studied by steady-state absorption and fast-transient optical spectroscopic techniques. Peridinin, fucoxanthin, uriolide acetate, and spheroidenone, which contain carbonyl functional groups in conjugation with the carbon-carbon pi-electron system, display broader absorption spectral features and are affected more by the solvent environment than neoxanthin and spheroidene, which do not contain carbonyl functional groups. The possible sources of the spectral broadening are explored by examining the absorption spectra at 77 K in glassy solvents. Also, carotenoids which contain carbonyls have complex transient absorption spectra and show a pronounced dependence of the excited singlet state lifetime on the solvent environment. It is postulated that these effects are related to the presence of an intramolecular charge transfer state strongly coupled to the S-1 (2(1)A(g)) excited singlet state. Structural variations in the series of carotenoids studied here make it possible to focus on the general molecular features that control the spectroscopic and dynamic properties of carotenoids. C1 Univ Connecticut, Dept Chem, Storrs, CT 06269 USA. Macquarie Univ, Dept Biol Sci, Sydney, NSW 2109, Australia. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Frank, HA (reprint author), Univ Connecticut, Dept Chem, U-60, Storrs, CT 06269 USA. RI Gosztola, David/D-9320-2011 OI Gosztola, David/0000-0003-2674-1379 NR 42 TC 205 Z9 210 U1 2 U2 30 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 11 PY 2000 VL 104 IS 18 BP 4569 EP 4577 DI 10.1021/jp000079u PG 9 WC Chemistry, Physical SC Chemistry GA 313MM UT WOS:000087003500039 ER PT J AU Maurer, SM Firestone, RB Scriver, CR AF Maurer, SM Firestone, RB Scriver, CR TI Science's neglected legacy SO NATURE LA English DT Editorial Material C1 Ernest Orlando Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. McGill Univ, Montreal Childrens Hosp, Res Inst, Montreal, PQ H3H 1P3, Canada. RP Maurer, SM (reprint author), 2632 Hilgard St, Berkeley, CA 94709 USA. NR 11 TC 27 Z9 28 U1 1 U2 3 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 11 PY 2000 VL 405 IS 6783 BP 117 EP 120 DI 10.1038/35012169 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 314WG UT WOS:000087080100021 PM 10821250 ER PT J AU Jaime, M Movshovich, R Stewart, GR Beyermann, WP Berisso, MG Hundley, MF Canfield, PC Sarrao, JL AF Jaime, M Movshovich, R Stewart, GR Beyermann, WP Berisso, MG Hundley, MF Canfield, PC Sarrao, JL TI Closing the spin gap in the Kondo insulator Ce3Bi4Pt3 at high magnetic fields SO NATURE LA English DT Article ID YBB12; HEAT; STATE; SMB6 AB Kondo insulator materials(1)-such as CeRhAs, CeRhSb, YbB12, Ce3Bi4Pt3 and SmB6-are 3d, 4f and 5f intermetallic compounds that have attracted considerable interest in recent years(2-5). At high temperatures, they behave like metals. But as temperature is reduced, an energy gap opens in the conduction band at the Fermi energy and the materials become insulating. This contrasts with other f-electron compounds, which are metallic at all temperatures. The formation of the gap in Kondo insulators has been proposed to be a consequence of hybridization between the conduction band and the f-electron levels(6,7), giving a 'spin' gap. If this is indeed the case, metallic behaviour should be recovered when the gap is closed by changing external parameters, such as magnetic field or pressure. Some experimental evidence suggests that the gap can be closed in SmB6 (refs 5, 8) and YbB12 (ref. 9). Here we present specific-heat measurements of Ce3Bi4Pt3 in d.c. and pulsed magnetic fields up to 60 tesla. Numerical results and the analysis of our data using the Coqblin-Schrieffer model demonstrate unambiguously a field-induced insulator-to-metal transition. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Florida, Gainesville, FL 32611 USA. Univ Calif Riverside, Riverside, CA 92521 USA. Ctr Atom Bariloche, RA-8400 Bariloche, Rio Negro, Argentina. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. RP Jaime, M (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Canfield, Paul/H-2698-2014; Jaime, Marcelo/F-3791-2015 OI Jaime, Marcelo/0000-0001-5360-5220 NR 25 TC 64 Z9 64 U1 4 U2 29 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 11 PY 2000 VL 405 IS 6783 BP 160 EP 163 DI 10.1038/35012027 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 314WG UT WOS:000087080100043 ER PT J AU Mao, GM Perea, RF Howells, WS Price, DL Saboungi, ML AF Mao, GM Perea, RF Howells, WS Price, DL Saboungi, ML TI Relaxation in polymer electrolytes on the nanosecond timescale SO NATURE LA English DT Article ID POLY(ETHYLENE OXIDE); CONDUCTIVITY AB The relation between mechanical and electrical relaxation in polymer/lithium-salt complexes is a fascinating and still unresolved problem in condensed-matter physics(1), yet has an important bearing on the viability of such materials for use as electrolytes in lithium batteries. At room temperature, these materials are biphasic: they consist of both fluid amorphous regions and salt-enriched crystalline regions. Ionic conduction is known to occur predominantly in the amorphous fluid regions. Although the conduction mechanisms are not yet fully understood(2), it is widely accepted that lithium ions, coordinated with groups of ether oxygen atoms on single or perhaps double polymer chains, move through re-coordination with other oxygen-bearing groups(3,4). The formation and disruption of these coordination bonds must be accompanied by strong relaxation of the local chain structure. Here we probe the relaxation on a nanosecond timescale using quasielastic neutron scattering, and we show that at least two processes are involved: a slow process with a translational character and one or two fast processes with a rotational character. Whereas the former reflects the slowing-down of the translational relaxation commonly observed in polyethylene oxide and other polymer melts, the latter appears to be unique to the polymer electrolytes and has not (to our knowledge) been observed before. A clear picture emerges of the lithium cations forming crosslinks between chain segments and thereby profoundly altering the dynamics of the polymer network. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. RP Saboungi, ML (reprint author), Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Mao, Guomin/G-3933-2010; Price, David Long/A-8468-2013; Saboungi, Marie-Louise/C-5920-2013; Fernandez-Perea, Ricardo/E-9118-2016 OI Saboungi, Marie-Louise/0000-0002-0607-4815; Fernandez-Perea, Ricardo/0000-0002-4011-2344 NR 16 TC 83 Z9 83 U1 7 U2 64 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 11 PY 2000 VL 405 IS 6783 BP 163 EP 165 DI 10.1038/35012032 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 314WG UT WOS:000087080100044 ER PT J AU Thom, J AF Thom, J TI Time-dependent B-s(0)-(B)over-bar(s)(0) mixing using inclusive and semileptonic B decays at SLD SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Conference on B-Physics CY JUN 21-25, 1999 CL BLED, SLOVENIA SP Slovenian Minist Sci & Technol DE (BsBs0)-B-0 mixing AB We have searched for time-dependent B-s(0)-(B) over bar(s)(0) mixing using a sample of 400 000 hadronic Z(0) decays collected by the SLD experiment at the SLC. The analyses take advantage of the excellent vertexing efficiency and resolution of the pixel-based CCD Vertex Detector which provides a B decay length resolution of approximately 100 mu m All analyses determine the B hadron flavor at production by exploiting the large forward-backward asymmetry of polarized Z(0) --> b (b) over bar decays. This flavor tag is enhanced by incorporating additional information from the hemisphere opposite that of the reconstructed B decay. In one analysis, B decay vertices are reconstructed inclusively with a topological technique, and separation between B-s(0) and (B) over bar(s)(0) decays is based on the reconstruction of a "charge dipole" of the topological vertices to exploit the B-s(0) --> D-s(-) cascade charge structure. The other two analyses select semileptonic decays to tag the B flavor at decay and reconstruct the B decay vertex by intersecting the lepton with either all tracks in the nearest jet or the trajectory of a topologically reconstructed D vertex. The three analyses are combined to exclude the following values of the oscillation frequency: Delta m(s) < 5.3 and 6.0 ps(-1) < Delta m(s) < 11.5 ps(-1). Future prospects are outlined. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Thom, J (reprint author), Stanford Univ, Stanford Linear Accelerator Ctr, MS96,POB 4349, Stanford, CA 94309 USA. NR 4 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 2000 VL 446 IS 1-2 BP 53 EP 58 DI 10.1016/S0168-9002(00)00021-8 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 318YN UT WOS:000087312400007 ER PT J AU Maksimovic, P AF Maksimovic, P TI Recent B-physics results from CDF SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 6th International Conference on B-Physics CY JUN 21-25, 1999 CL BLED, SLOVENIA SP Slovenian Minist Sci & Technol ID SILICON VERTEX DETECTOR; P(P)OVER-BAR COLLISIONS; ROOT-S=1.8 TEV; DECAYS; MESON; FRAGMENTATION; FERMILAB; J/PSI AB We present recent results from the CDF experiment, based on the data taken between 1992 and 1995 (Tevatron Run I). We classify the results according to the need to know the initial flavor of the B meson. Of the analyses that do not require this knowledge, we focus on the measurements of cross-sections, lifetimes, and polarizations. Next, we describe the analyses based on the knowledge of the initial flavor of the B meson: several B-0 mixing measurements (which are also used to study the flavor determination), a B-s mixing search, and a recently updated limit on sin(2 beta). (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Harvard Univ, Fermilab, Batavia, IL 60510 USA. RP Maksimovic, P (reprint author), Harvard Univ, Fermilab, Mail Stop 318,POB 500, Batavia, IL 60510 USA. NR 23 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAY 11 PY 2000 VL 446 IS 1-2 BP 106 EP 119 DI 10.1016/S0168-9002(00)00018-8 PG 14 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 318YN UT WOS:000087312400016 ER PT J AU Vardaci, E Kaplan, M Parker, WE Moses, DJ Boger, JT Gilfoyle, GJ McMahan, MA Montoya, M AF Vardaci, E Kaplan, M Parker, WE Moses, DJ Boger, JT Gilfoyle, GJ McMahan, MA Montoya, M TI Search for ternary fragmentation in the reaction 856 MeV Mo-98+V-51: kinematic probing of intermediate-mass-fragment emissions SO PHYSICS LETTERS B LA English DT Article DE heavy ion reactions; intermediate mass fragments; fission ID LIGHT-CHARGED-PARTICLE; 337 MEV AR-40+(NAT)AG; REVERSED KINEMATICS; MEV KR-86+CU-63; FISSION; COLLISIONS; MO-100+MO-100; SN-120+SN-120; SB-121+AL-27; MECHANISMS AB A new technique has been applied to coincidence measurements between fission fragments (FF) and intermediate mass fragments (IMF) emitted from the composite system Tb-149(65) at an excitation energy of 224 MeV. The method permits simultaneous observation of IMF emissions along and normal to the FF separation axes. For the integrated total of 0.10 +/- 0.02 IMF emitted per fission, we find no significant correlation with FF direction, suggesting that IMFs associated with fission reactions are predominantly emitted from the system prior to fission. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Carnegie Mellon Univ, Dept Chem, Pittsburgh, PA 15213 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Univ Richmond, Dept Phys, Richmond, VA 23173 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Vardaci, E (reprint author), Univ Naples Federico II, Dipartimento Sci Fisiche, I-80126 Naples, Italy. OI Montoya, Modesto/0000-0002-3376-1872 NR 19 TC 8 Z9 8 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD MAY 11 PY 2000 VL 480 IS 3-4 BP 239 EP 244 DI 10.1016/S0370-2693(00)00407-X PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 315PC UT WOS:000087121300001 ER PT J AU Yocky, DA Jakowatz, CV Eichel, PH AF Yocky, DA Jakowatz, CV Eichel, PH TI Interpolated spatially variant apodization in synthetic aperture radar imagery SO APPLIED OPTICS LA English DT Article AB The original formulation of spatially variant apodization for complex synthetic aperture radar imagery concentrated on integer-oversampled data. Noninteger-oversampled data presented previously [IEEE Trans. Aerosp. Electron. Syst. 31, 267 (1995)] suggested use of different weightings in the algorithm. An alternative noninteger-oversampled approach that employs the same apodization concept but uses local spatial interpolation is presented. With this approach the combined image formation, apodization, and detection of 1.3x-versus-2.0x oversampled data can be performed in half the time without loss of image quality. (C) 2000 Optical Society of America. OCIS codes: 280.6730, 100.2000, 100.2980. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Yocky, DA (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM dayocky@sandia.gov NR 3 TC 2 Z9 2 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 10 PY 2000 VL 39 IS 14 BP 2310 EP 2312 DI 10.1364/AO.39.002310 PG 3 WC Optics SC Optics GA 312JJ UT WOS:000086939900007 PM 18345138 ER PT J AU Joffre, M Fischer, P Frieman, J McKay, T Mohr, JJ Nichol, RC Johnston, D Sheldon, E Bernstein, G AF Joffre, M Fischer, P Frieman, J McKay, T Mohr, JJ Nichol, RC Johnston, D Sheldon, E Bernstein, G TI Weak gravitational lensing by the nearby cluster Abell 3667 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (Abell 3667); gravitational lensing ID DARK-MATTER; GALAXIES; A3667; ARC AB We present two weak lensing reconstructions of the nearby (z(cl) = 0.055) merging cluster Abell 3667, based on observations taken similar to 1 yr apart under different seeing conditions. This is the lowest redshift cluster with a weak lensing mass reconstruction to date. The reproducibility of features in the two mass maps demonstrates that weak lensing studies of low-redshift clusters are feasible. These data constitute the first results from an Xray luminosity-selected weak lensing survey of 19 low-redshift (z < 0.1) southern clusters. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. RP Joffre, M (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI McKay, Timothy/C-1501-2009 OI McKay, Timothy/0000-0001-9036-6150 NR 20 TC 28 Z9 28 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2000 VL 534 IS 2 BP L131 EP L134 DI 10.1086/312681 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 320ZB UT WOS:000087429500004 ER PT J AU Kepler, SO Mukadam, A Winget, DE Nather, RE Metcalfe, TS Reed, MD Kawaler, SD Bradley, PA AF Kepler, SO Mukadam, A Winget, DE Nather, RE Metcalfe, TS Reed, MD Kawaler, SD Bradley, PA TI Evolutionary timescale of the pulsating white dwarf G117-B15A: The most stable optical clock known SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : evolution; stars : individual (G117-B15A); stars : oscillations ID ZZ-CETI STARS; WHOLE EARTH TELESCOPE; PERIOD CHANGE; MODELS; CONSTRAINTS AB We observe G117-B15A, the most precise optical clock known, to measure the rate of change of the main pulsation period of this blue-edge DAV white dwarf. Even though the obtained value is only within 1 sigma, (P)over dot = (2.3 +/- 1.4) x 10(-15) s s(-1), it is already constraining the evolutionary timescale of this cooling white dwarf star. C1 UFRGS, Inst Fis, BR-91501900 Porto Alegre, RS, Brazil. Univ Texas, Dept Astron, Austin, TX 78712 USA. Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Kepler, SO (reprint author), UFRGS, Inst Fis, BR-91501900 Porto Alegre, RS, Brazil. RI Metcalfe, Travis/A-9388-2008; Kepler, S. O. /H-5901-2012 OI Metcalfe, Travis/0000-0003-4034-0416; Kepler, S. O. /0000-0002-7470-5703 NR 33 TC 55 Z9 55 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 10 PY 2000 VL 534 IS 2 BP L185 EP L188 DI 10.1086/312664 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 320ZB UT WOS:000087429500017 ER PT J AU Barenblatt, GI Chorin, AJ Prostokishin, VM AF Barenblatt, GI Chorin, AJ Prostokishin, VM TI Self-similar intermediate structures in turbulent boundary layers at large Reynolds numbers SO JOURNAL OF FLUID MECHANICS LA English DT Article ID SCALING LAWS; SHEAR FLOWS; LOCAL-STRUCTURE AB Processing the data from a large variety of zero-pressure-gradient boundary layer flows shows that the Reynolds-number-dependent scaling law, which the present authors obtained earlier for pipes, gives an accurate description of the velocity distribution in a self-similar intermediate region adjacent to the viscous sublayer next to the wall. The appropriate length scale that enters the definition of the boundary layer Reynolds number is found for all the flows under investigation. Another intermediate self-similar region between the free stream and the first intermediate region is found under conditions of weak free-stream turbulence. The effects of turbulence in the free stream and of wall roughness are assessed, and conclusions are drawn. C1 Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Russian Acad Sci, PP Shirshov Oceanol Inst, Moscow 117218, Russia. RP Barenblatt, GI (reprint author), Univ Calif Berkeley, Dept Math, Berkeley, CA 94720 USA. OI Prostokishin, Valeriy/0000-0001-6185-9642 NR 27 TC 46 Z9 47 U1 1 U2 6 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD MAY 10 PY 2000 VL 410 BP 263 EP 283 DI 10.1017/S0022112099008034 PG 21 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 322RP UT WOS:000087522800010 ER PT J AU Skurski, P Simons, J Wang, XB Wang, LS AF Skurski, P Simons, J Wang, XB Wang, LS TI Experimental and theoretical investigations of the stability of two small gaseous dicarboxylate dianions: Acetylene dicarboxylate and succinate SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID MULTIPLY-CHARGED ANIONS; PHOTODETACHMENT PHOTOELECTRON-SPECTROSCOPY; REPULSIVE COULOMB BARRIER; GAS-PHASE; GREENS-FUNCTION; CLOSED-SHELL; IONS; CLUSTERS; ATOMS; STABILIZATION AB The stability of two small dicarboxylate dianions, (O2C-C=C-CO2)(2-) (AD(2-)) and (O2C-CH2-CH2-CO2)(2-) (SD2-) has been studied in the gas phase by using electrospray mass spectrometry, photoelectron spectroscopy, and ab initio calculations. Despite their similar charge-separation and size, AD(2-) was observed abundantly, whereas SD2- was very difficult to detect. Our ab initio calculation predicts that AD(2-) is adiabatically stable with respect to electron loss whereas SD2- is not. These calculations show that AD(2-) has a D-2d structure with 0.418 eV adiabatic and 0.69 eV vertical electron binding energies, compared to the experimental values of 0.30 (0.10) and 0.60 (0.10) eV, respectively. SD2- was found to have a C-2h structure with a negative adiabatic electron binding energy (-0.086 eV). Our detailed theoretical analysis indicates that while the two excess charges in SD2- are completely localized on the terminal carboxylate groups; there is significant delocalization of the excess charges into the -CC- pi-type orbitals in AD(2-). The D-2d structure of the AD(2-) dianion allows each carboxylate to interact with one of the two perpendicular pi-type orbitals of the acetylene moiety, thus providing extra stabilization while minimizing the Coulomb repulsion. C1 Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Washington State Univ, Dept Phys, Richland, WA 99352 USA. Pacific NW Natl Lab, WR Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Simons, J (reprint author), Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. NR 54 TC 32 Z9 32 U1 0 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD MAY 10 PY 2000 VL 122 IS 18 BP 4499 EP 4507 DI 10.1021/ja000371f PG 9 WC Chemistry, Multidisciplinary SC Chemistry GA 313NW UT WOS:000087006600030 ER PT J AU Hinks, DG Chmaissem, O Ely, L Scott, C Jorgensen, JD Akujieze, JK AF Hinks, DG Chmaissem, O Ely, L Scott, C Jorgensen, JD Akujieze, JK TI Reaction of YBa2Cu3O6 with Br-2: oxidation and formation of nanoscale YBa2Cu3O7 SO PHYSICA C LA English DT Article DE Br intercalation; O diffusion; YBa2Cu3O6Br ID TETRAGONAL YBA2CU3O7-X; HALOGEN ATOMS; SUPERCONDUCTIVITY; OXYGEN; DIFFUSION; PHASES; VAPORS AB We have investigated the products of the reaction of reduced YBa2Cu3O6+x with bromine using thermal analysis and neutron powder diffraction. We find that bromine is not intercalated into the 123 structure. The reaction reduces the particle size of the 123 material allowing the oxygen formed at the reacting surface to diffuse into the material in a reasonable time scale at the low reaction temperatures. (C) 2000 Elsevier Science B.V. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Sci & Technol Ctr Superconduct, Argonne, IL 60439 USA. No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA. Chicago State Univ, Dept Chem & Phys, Chicago, IL 60628 USA. RP Hinks, DG (reprint author), Argonne Natl Lab, Div Mat Sci, Bldg 223,9700 S Cass Ave, Argonne, IL 60439 USA. NR 20 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 10 PY 2000 VL 333 IS 1-2 BP 1 EP 12 DI 10.1016/S0921-4534(00)00094-0 PG 12 WC Physics, Applied SC Physics GA 318CF UT WOS:000087265800001 ER PT J AU Staub, U Soderholm, L Skanthakumar, S Osborn, R Fauth, F Ritter, C AF Staub, U Soderholm, L Skanthakumar, S Osborn, R Fauth, F Ritter, C TI The magnetic properties of Pr in the Pb2Sr2PrCu3O8+delta cuprate SO PHYSICA C LA English DT Article DE magnetic; Pr; cuprate ID NORMAL-STATE PROPERTIES; OXIDATION-STATE; LOCAL MAGNETISM; CRYSTAL FIELDS; GROUND-STATE; PR-141 NMR; HO3+ IONS; PRBA2CU3O7; SUPERCONDUCTIVITY; SUPPRESSION AB Inelastic and elastic neutron scattering data on Pb2Sr2PrCu3O8+delta are presented. Magnetic ordering of the Pr moments is found to be analogous to the Tb analogue, interpreted with two different wave vectors k = 0 0 0 and 0 0 1/2. A molecular field-induced shift is observed in the low-energy inelastic neutron scattering (INS) data when going through the Neel temperature. This shift is quantitatively accounted for by the magnetic order of the Pr sublattice. The crystalline-electric-field (CEF) potential has been determined from the observed magnetic excitations and is compared with those of Pr in other cuprates. These results underline the relevance of the quasi-triplet ground state splitting for T-c suppression by Pr in the cuprate superconductors. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Staub, U (reprint author), Paul Scherrer Inst, Swiss Light Source, CH-5232 Villigen, Switzerland. RI Osborn, Raymond/E-8676-2011; Staub, Urs/C-4914-2015; Fauth, Francois/K-9643-2014 OI Osborn, Raymond/0000-0001-9565-3140; Fauth, Francois/0000-0001-9465-3106 NR 43 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 10 PY 2000 VL 333 IS 1-2 BP 13 EP 22 DI 10.1016/S0921-4534(00)00033-2 PG 10 WC Physics, Applied SC Physics GA 318CF UT WOS:000087265800002 ER PT J AU Bhattacharya, RN Wu, HL Wang, YT Blaugher, RD Yang, SX Wang, DZ Ren, ZF Tu, Y Verebelyi, DT Christen, DK AF Bhattacharya, RN Wu, HL Wang, YT Blaugher, RD Yang, SX Wang, DZ Ren, ZF Tu, Y Verebelyi, DT Christen, DK TI Improved electrodeposition process for the preparation of superconducting thallium oxide films SO PHYSICA C LA English DT Article DE thick film; electrodeposition; Tl-oxides AB We report on developing a two-layer process to deposit biaxially textured Tl-oxide films by electrodeposition (ED) on Ag-coated, single-crystal substrates. Pole-figure measurements of two-layer, electrodeposited (Tl,Bi)-(Sr,Ba)-Ca-Cu-O (TBSBCCO) films on 300 Angstrom Ag/LaAlO3 (LAO), with thickness between 1 and 5 mu m, clearly show strong biaxial texturing. The omega scan and phi scan of 1.6 mu m (TlBi)(0.9)Sr1.6Ba0.4Ca2Cu3Ag0.2Ox films indicate the full width at half maximum (FWHM) of only 0.92 degrees and 0.6 degrees, respectively, indicating a very high-quality film prepared by the ED process. Transport measurements for the electrodeposited, thallium-oxide-based superconductor films show values above 10(6) A/cm(2) at 77 K in zero field. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Renewable Energy Lab, Golden, CO 80401 USA. Boston Coll, Chestnut Hill, MA 02467 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Bhattacharya, RN (reprint author), Natl Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80401 USA. RI Ren, Zhifeng/B-4275-2014 NR 5 TC 17 Z9 17 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD MAY 10 PY 2000 VL 333 IS 1-2 BP 59 EP 64 DI 10.1016/S0921-4534(00)00020-4 PG 6 WC Physics, Applied SC Physics GA 318CF UT WOS:000087265800007 ER PT J AU de Arellano-Lopez, AR Melendez-Martinez, JJ Dominguez-Rodriguez, A Routbort, JL AF de Arellano-Lopez, AR Melendez-Martinez, JJ Dominguez-Rodriguez, A Routbort, JL TI Creep of Al2O3 containing a small volume fraction of SiC-whiskers SO SCRIPTA MATERIALIA LA English DT Article DE creep; ceramic; whisker; composite ID REINFORCED AL2O3; DEFORMATION; MECHANISMS; COMPOSITES; ALUMINA; FLOW C1 Univ Sevilla, Dept Fis Mat Condensada, Seville, Spain. Argonne Natl Lab, Div Energy Technol, Argonne, IL 60439 USA. RP de Arellano-Lopez, AR (reprint author), Univ Sevilla, Dept Fis Mat Condensada, Seville, Spain. RI Melendez, Juan Jose/A-6524-2013; OI Melendez, Juan Jose/0000-0003-1036-6666; R. de Arellano Lopez, Antonio/0000-0002-7443-0244; Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 12 TC 1 Z9 1 U1 1 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6462 J9 SCRIPTA MATER JI Scr. Mater. PD MAY 10 PY 2000 VL 42 IS 10 BP 987 EP 991 DI 10.1016/S1359-6462(00)00334-1 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 316LM UT WOS:000087168600010 ER PT J AU Sautet, P Rose, MK Dunphy, JC Behler, S Salmeron, M AF Sautet, P Rose, MK Dunphy, JC Behler, S Salmeron, M TI Adsorption and energetics of isolated CO molecules on Pd(111) SO SURFACE SCIENCE LA English DT Article DE carbon monoxide; chemisorption; density functional calculations; palladium; scanning tunneling microscopy; semiempirical models and model calculations; single crystal surfaces ID SINGLE-CRYSTAL SURFACES; DIFFUSION; DYNAMICS; PD AB The adsorption of CO on Pd(111) has been studied with scanning tunneling microscopy in the very low coverage regime. Isolated CO molecules were imaged with two different corrugations of similar to 0.25 Angstrom and similar to 0.15 Angstrom, which are attributed to adsorption of the hcp and fee hollow sites. Total energy calculations reveal that these two sites are the most favorable ones. Calculated image profiles using the ESQC method agree well with the experimental corrugations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Ecole Normale Super Lyon, Chim Theor Lab, F-69364 Lyon 07, France. Inst Rech Catalyse, CNRS, F-69626 Villeurbanne, France. RP Salmeron, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Sautet, Philippe/G-3710-2014 OI Sautet, Philippe/0000-0002-8444-3348 NR 17 TC 57 Z9 59 U1 1 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 10 PY 2000 VL 453 IS 1-3 BP 25 EP 31 DI 10.1016/S0039-6028(00)00243-0 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 318UN UT WOS:000087302400012 ER PT J AU Kendelewicz, T Liu, P Doyle, CS Brown, GE Nelson, EJ Chambers, SA AF Kendelewicz, T Liu, P Doyle, CS Brown, GE Nelson, EJ Chambers, SA TI Reaction of water with the (100) and (111) surfaces of Fe3O4 SO SURFACE SCIENCE LA English DT Article DE iron oxide; photoemission (total yield); sticking; water; X-ray emission ID MOLECULAR-BEAM EPITAXY; OXIDE SURFACES; PHOTOEMISSION; ALPHA-FE2O3(0001); FILMS; IRON; SPECTROSCOPY; CHEMISTRY; XPS AB We have examined changes in the electronic structure of magnetite (100) and (111) surfaces after reaction with water vapor (p(H2O) ranging from 10(-9) to 9 Torr) and liquid water at 298 K using chemical shifts in the O Is core level photoelectron spectra obtained with a synchrotron radiation source. The surfaces were prepared in ultra-high vacuum (UHV) from natural magnetite crystals. We found that the vapor pressure, p(H2O), at which water first reacts with magnetite is similar for the two surfaces (less than or equal to 10(-5) Torr for 3 min exposures, corresponding to doses of less than or equal to 1.8 x 10(3) Langmuirs) and is consistent with a small sticking coefficient. This reaction is manifested in the O Is spectra by the growth of a shoulder at about 1.5 eV tower kinetic energy than the main lattice oxygen feature. We attributed this new feature to hydroxyl groups resulting from dissociative chemisorption of water on the magnetite surfaces, initially on defect sites. p(H2O) for the onset of an extensive hydroxylation reaction is approximate to 10(-3) Torr (3 min dose or approximate to 1.8 x 10(5) Langmuirs). Magnetite (100) and (Ill)surfaces exposed to higher p(H2O) react more extensively, with hydroxylation extending several layers (approximate to 8 Angstrom) deep into the bulk. A comparison of O KVV Auger K-edge absorption spectra of water vapor-exposed magnetite (100) and (111) surfaces with the corresponding total yield spectra of goethite (alpha-FeOOH), limonite (FeOOH . nH(2)O), and hematite (alpha-Fe2O3) clearly shows that the reaction product on the magnetite surfaces is not goethite, limonite or hematite. In addition, similarity of the Fe L3M23M23 Auger yield L-edge absorption spectra before and after exposure of the magnetite (111) surface to liquid water indicates that the oxidation state of iron is unchanged, We also measured O Is chemical shifts on magnetite (111) surfaces which had been immersed in liquid water. Surprisingly, these immersion experiments resulted in smaller chemical shifts and lower intensities of hydroxyl features relative to magnetite samples exposed to the highest water vapor pressures (10 Torr for 3 min or 1.8 x 10(9) Langmuirs) in our dosing experiments. To assess the thermal stability of the hydroxylated surfaces. we conducted a series of stepwise annealing experiments to 700 degrees C. These annealing experiments indicate that once the magnetite surface is hydroxylated it is extremely difficult to thermally clean without Ar+ sputtering. O 2000 Published by Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. Pacific NW Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Kendelewicz, T (reprint author), Stanford Univ, Dept Geol & Environm Sci, Surface & Aqueous Geochem Grp, Stanford, CA 94305 USA. NR 32 TC 85 Z9 86 U1 5 U2 74 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 10 PY 2000 VL 453 IS 1-3 BP 32 EP 46 DI 10.1016/S0039-6028(00)00305-8 PG 15 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 318UN UT WOS:000087302400013 ER PT J AU Kuo, JS Rogers, JW AF Kuo, JS Rogers, JW TI Reaction of dimethylethylamine alane and ammonia on Si(100) during the atomic layer growth of AlN: static SIMS, TPSIMS, and TPD SO SURFACE SCIENCE LA English DT Article DE chemical vapor deposition; growth; nitrides; polycrystalline surfaces; secondary ion mass spectroscopy; semiconductor-insulator interfaces; surface chemical reaction; thermal desorption spectroscopy ID CHEMICAL-VAPOR-DEPOSITION; HETEROEPITAXIAL GROWTH; TRIMETHYLAMINE ALANE; ALUMINUM NITRIDE; THIN-FILMS; SILICON; NH3; DECOMPOSITION; SURFACES; ADSORPTION AB Dimethylethylamine alane [DMEAA; AlH(3):N(CH(3))(2)(CH(2)CH(3))] has been used as an Al source in the chemical vapor deposition of AIN. In the atomic layer growth mode, ammonia and DMEAA interact selectively by nucleophilic displacement. In the first part of this study, the surface adsorption and reaction processes are characterized with static secondary-ion mass spectrometry and temperature-programmed secondary-ion mass spectrometry. The secondary ion emission from DMEAA-covered Si surface shares similar general characteristics with the gas phase cracking pattern. The secondary ion emission spectrum is interpreted according to a unimolecular ion decomposition mechanism and is used as the fingerprint for the presence of molecular DMEAA. During the surface reaction between DMEAA and ammonia. the intensity of the fingerprint peaks diminish, representing the departure of the amine ligand. The thermal stability of DMEAA and its decomposition behavior on Si are also examined. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA. Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Rogers, JW (reprint author), Univ Washington, Dept Chem Engn, Box 351750, Seattle, WA 98195 USA. EM jw.rogers@pnl.gov NR 40 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 10 PY 2000 VL 453 IS 1-3 BP 119 EP 129 DI 10.1016/S0039-6028(00)00328-9 PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 318UN UT WOS:000087302400020 ER PT J AU Alfonso, DR Snyder, JA Jaffe, JE Hess, AC Gutowski, M AF Alfonso, DR Snyder, JA Jaffe, JE Hess, AC Gutowski, M TI First-principles studies of adsorption of CO on the Na(100) surface SO SURFACE SCIENCE LA English DT Article DE adsorption kinetics; chemisorption; density functional calculations; surface electronic phenomena (work function, surface potential, surface states, etc.) ID DENSITY-FUNCTIONAL THEORY; METAL-SURFACES; LI; CHEMISORPTION; ENERGIES; CLUSTERS; SYSTEMS AB We have investigated the interaction of CO with the Na(100) substrate in the framework of density functional theory formulated for periodic systems. We established that there is an attractive but weak chemisorption bond between CO and Na(100). The binding energy of the CO molecule at an on-top site and adsorbed normal to the surface with the carbon end down is similar to 0.25 eV for the Perdew-Burke-Enzerhof (PBE96) exchange correlation functional. The structural, electronic and vibrational properties indicate weakening of the intramolecular CO bond by adsorption on Na(100). The occupied orbitals of CO are generally shifted up in energy upon adsorption, with exception of the highest occupied orbital 5 sigma. The adsorbate-surface interaction is primarily characterized by: (i) partial charge transfer from the occupied 3sp band of Na to the CO antibonding 2 pi* orbital and (ii) the interaction between the 5 sigma orbital of CO and the metal states. (C) 2000 Elsevier science B.V. All rights reserved. C1 Pacific NW Natl Lab, Div Energy, Richland, WA 99352 USA. Univ Gdansk, Dept Chem, PL-80952 Gdansk, Poland. RP Gutowski, M (reprint author), Pacific NW Natl Lab, Div Energy, Richland, WA 99352 USA. NR 34 TC 4 Z9 4 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD MAY 10 PY 2000 VL 453 IS 1-3 BP 130 EP 136 DI 10.1016/S0039-6028(00)00331-9 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 318UN UT WOS:000087302400021 ER PT J AU Panofsky, WKH AF Panofsky, WKH TI National security and scientific communication SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Editorial Material C1 Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Panofsky, WKH (reprint author), 2575 Sand Hill Rd, Menlo Park, CA 94025 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 9 PY 2000 VL 97 IS 10 BP 5034 EP 5036 DI 10.1073/pnas.100114597 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 313KH UT WOS:000086998500008 PM 10779567 ER PT J AU Hung, LW Holbrook, EL Holbrook, SR AF Hung, LW Holbrook, EL Holbrook, SR TI The crystal structure of the Rev binding element of HIV-1 reveals novel base pairing and conformational variability SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID OXYTRICHA TELOMERIC DNA; RNA APTAMER COMPLEX; RESPONSIVE ELEMENT; MAJOR GROOVE; ALPHA-HELIX; PEPTIDE; RECOGNITION; PROTEIN; NMR; DOMAIN AB The crystal and molecular structure of an RNA duplex corresponding to the high affinity Rev protein binding element (RBE) has been determined at 2.1-Angstrom resolution. Four unique duplexes are present in the crystal, comprising two structural variants. In each duplex, the RNA double helix consists of an annealed 12-mer and 14-mer that form an asymmetric internal loop consisting of G-G and G-A noncanonical base pairs and a flipped-out uridine. The 12-mer strand has an A-form conformation, whereas the 14-mer strand is distorted to accommodate the bulges and noncanonical base pairing. In contrast to the NMR model of the unbound RBE, an asymmetric: G-G pair with N2-N7 and N1-O6 hydrogen bonding, is formed in each helix. The G-A base pairing agrees with the NMR structure in one structural variant, but forms a novel water-mediated pair in the other. A backbone flip and reorientation of the G-G base pair is required to assume the RBE conformation present in the NMR model of the complex between the RBE and the Rev peptide. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Phys Biosci, Dept Biol Struct, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Phys Biosci, Macromol Crystallog Facil, Berkeley, CA 94720 USA. RP Holbrook, SR (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Div Phys Biosci, Dept Biol Struct, Melvin Calvin Bldg, Berkeley, CA 94720 USA. FU NIGMS NIH HHS [GM 4921501] NR 34 TC 38 Z9 38 U1 0 U2 4 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 9 PY 2000 VL 97 IS 10 BP 5107 EP 5112 DI 10.1073/pnas.090588197 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 313KH UT WOS:000086998500021 PM 10792052 ER PT J AU Deniz, AA Laurence, TA Beligere, GS Dahan, M Martin, AB Chemla, DS Dawson, PE Schultz, PG Weiss, S AF Deniz, AA Laurence, TA Beligere, GS Dahan, M Martin, AB Chemla, DS Dawson, PE Schultz, PG Weiss, S TI Single-molecule protein folding: Diffusion fluorescence resonance energy transfer studies of the denaturation of chymotrypsin inhibitor 2 SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID NATIVE CHEMICAL LIGATION; TRANSITION-STATE; IDENTIFICATION; SIMULATIONS; LANDSCAPE; PEPTIDES; DYNAMICS; KINETICS AB We report single-molecule folding studies of a small, single-domain protein, chymotrypsin inhibitor 2 (CI2). CI2 is an excellent model system for protein folding studies and has been extensively studied, both experimentally (at the ensemble level) and theoretically. Conformationally assisted ligation methodology was used to synthesize the proteins and site-specifically label them with donor and acceptor dyes. Folded and denatured subpopulations were observed by fluorescence resonance energy transfer (FRET) measurements on freely diffusing single protein molecules. Properties of these subpopulations were directly monitored as a function of guanidinium chloride concentration. It is shown that new information about different aspects of the protein folding reaction can be extracted from such subpopulation properties. Shifts in the mean transfer efficiencies are discussed, FRET efficiency distributions are translated into potentials, and denaturation curves are directly plotted from the areas of the FRET peaks. Changes in stability caused by mutation also are measured by comparing pseudo wild-type CI2 with a destabilized mutant (K17G). Current limitations and future possibilities and prospects for single-pair FRET protein folding investigations are discussed. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Scripps Res Inst, Dept Chem, Skaggs Inst Chem Biol, La Jolla, CA 92037 USA. Scripps Res Inst, Dept Cell Biol, Skaggs Inst Chem Biol, La Jolla, CA 92037 USA. RP Schultz, PG (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RI Laurence, Ted/E-4791-2011; Dahan, Maxime /F-1740-2010; weiss, shimon/B-4164-2009 OI Laurence, Ted/0000-0003-1474-779X; weiss, shimon/0000-0002-0720-5426 FU NIGMS NIH HHS [R01 GM059380, GM59380, R01 GM49220-09] NR 36 TC 352 Z9 359 U1 2 U2 78 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAY 9 PY 2000 VL 97 IS 10 BP 5179 EP 5184 DI 10.1073/pnas.090104997 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 313KH UT WOS:000086998500034 PM 10792044 ER PT J AU Wu, ML Guruz, MU Dravid, VP Chung, YW Anders, S Freire, FL Mariotto, G AF Wu, ML Guruz, MU Dravid, VP Chung, YW Anders, S Freire, FL Mariotto, G TI Formation of carbon nitride with sp(3)-bonded carbon in CNx/ZrN superlattice coatings SO APPLIED PHYSICS LETTERS LA English DT Article ID THIN-FILMS; DEPOSITION; MULTILAYERS; BETA-C3N4; ARC AB A carbon nitride phase with primarily sp(3)-bonded carbon is stabilized in CNx/ZrN superlattice coatings. Rutherford backscattering spectrometry measurements give a N/C atomic ratio similar to 1.3 for the CNx layers. High-resolution transmission electron microscopy and Z-contrast imaging from the superlattice show a well-defined layer structure. Raman and near-edge x-ray absorption fine structure spectroscopy results reveal the formation of sp(3)-bonded carbon atoms in short-period CNx/ZrN superlattices. (C) 2000 American Institute of Physics. [S0003-6951(00)00919-0]. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Pontificia Univ Catolica Rio de Janeiro, Dept Fis, BR-22452970 Rio De Janeiro, Brazil. Univ Trent, Inst Nazl Fis Mat, I-38050 Trent, Italy. Univ Trent, Dipartimento Fis, I-38050 Trent, Italy. RP Chung, YW (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Dravid, Vinayak/B-6688-2009; Chung, Yip-Wah/B-7506-2009; Mariotto, Gino/B-1629-2013; Mariotto, Gino/M-3769-2015; Raoux, Simone/G-3920-2016 OI Mariotto, Gino/0000-0002-0035-1404; NR 23 TC 24 Z9 25 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 8 PY 2000 VL 76 IS 19 BP 2692 EP 2694 DI 10.1063/1.126743 PG 3 WC Physics, Applied SC Physics GA 309QB UT WOS:000086778200016 ER PT J AU Beck, U Metzger, TH Peisl, J Patel, JR AF Beck, U Metzger, TH Peisl, J Patel, JR TI Diffuse x-ray rods and scattering from point defect clusters in ion implanted silicon SO APPLIED PHYSICS LETTERS LA English DT Article ID DISLOCATION LOOPS; BORON; DAMAGE; SI AB We have studied the early stages of annealing in boron implanted silicon. In a grazing incidence diffuse scattering investigation of implantation-induced defects, we have observed narrow diffuse rods of intensity along < 111 > directions. These diffuse streaks arise from stacking faults formed during annealing in the 1000 degrees C range. From the width of the diffuse streak the average size of the stacking fault is 71 nm in diameter. These intensity rods are distinct from the point defect or point defect cluster scattering in the tails of the Bragg peak (Huang scattering). From the q dependence of the scattered intensity in the Huang scattering region we find clear evidence for defect clusters with an average effective size of 4 nm, remarkably independent of the annealing temperature. These observations are discussed in the context of the enhanced diffusion of implanted boron over its bulk value referred to as transient enhanced diffusion. (C) 2000 American Institute of Physics. [S0003-6951(00)01519-9]. C1 Univ Munich, Sekt Phys, D-80539 Munich, Germany. Univ Munich, CENS, D-80539 Munich, Germany. Stanford Univ, Stanford Linear Accelerator Ctr, SSRL, Stanford, CA 94309 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, ALS, Berkeley, CA 94720 USA. RP Beck, U (reprint author), Univ Munich, Sekt Phys, Geschwister Scholl Pl 1, D-80539 Munich, Germany. NR 14 TC 18 Z9 18 U1 3 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 8 PY 2000 VL 76 IS 19 BP 2698 EP 2700 DI 10.1063/1.126447 PG 3 WC Physics, Applied SC Physics GA 309QB UT WOS:000086778200018 ER PT J AU Seeck, OH Kaendler, ID Tolan, M Shin, K Rafailovich, MH Sokolov, J Kolb, R AF Seeck, OH Kaendler, ID Tolan, M Shin, K Rafailovich, MH Sokolov, J Kolb, R TI Analysis of x-ray reflectivity data from low-contrast polymer bilayer systems using a Fourier method SO APPLIED PHYSICS LETTERS LA English DT Article ID INTERACTION PARAMETER; THIN-FILMS AB X-ray reflectivity data of polymer bilayer systems have been analyzed using a Fourier method which takes into account different limits of integration in q-space. It is demonstrated that the interfacial parameters can be determined with high accuracy although the difference in the electron density (the contrast) of the two polymers is extremely small. This method is not restricted to soft-matter thin films. It can be applied to any reflectivity data from low-contrast layer systems. (C) 2000 American Institute of Physics. [S0003- 6951(00)03719-0]. C1 Argonne Natl Lab, Adv Photon Source, XFD, Argonne, IL 60439 USA. Univ Kiel, Inst Expt & Angew Phys, D-24098 Kiel, Germany. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RP Seeck, OH (reprint author), DESY, HASYLAB, Notkestr 85, D-22603 Hamburg, Germany. RI Shin, Kwanwoo /C-4979-2012; OI Shin, Kwanwoo/0000-0002-7563-8581 NR 13 TC 61 Z9 61 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 8 PY 2000 VL 76 IS 19 BP 2713 EP 2715 DI 10.1063/1.126452 PG 3 WC Physics, Applied SC Physics GA 309QB UT WOS:000086778200023 ER PT J AU Chang, PC Baca, AG Li, NY Sharps, PR Hou, HQ Laroche, JR Ren, F AF Chang, PC Baca, AG Li, NY Sharps, PR Hou, HQ Laroche, JR Ren, F TI InGaAsN/AlGaAs P-n-p heterojunction bipolar transistor SO APPLIED PHYSICS LETTERS LA English DT Article ID BAND-GAP; EPITAXY AB We have demonstrated a functional P-n-p heterojunction bipolar transistor (HBT) using InGaAsN. The metalorganic-vapor-phase-epitaxy-grown Al0.3Ga0.7As/In0.03Ga0.97As0.99N0.01 HBT takes advantage of the narrower band gap energy (E-g=1.2 eV) of In0.03Ga0.97As0.99N0.01, which is lattice matched to GaAs. Compared with the Al0.3Ga0.7As/GaAs material system, the Al0.3Ga0.7As/In0.03Ga0.97As0.99N0.01 material system has a larger conduction-band offset, while the valence-band offset remains comparable. This characteristic band alignment is very suitable for P-n-p HBT applications. The device's peak current gain is 23, and it has a turn-on voltage of 0.77 V, which is 0.25 V lower than in a comparable P-n-p Al0.3Ga0.7As/GaAs HBT. (C) 2000 American Institute of Physics. [S0003-6951(00)04619-2]. C1 Sandia Natl Labs, Albuquerque, NM 87123 USA. EMCORE Corp, Emcore Photovolt, Albuquerque, NM 87123 USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. RP Chang, PC (reprint author), Sandia Natl Labs, Albuquerque, NM 87123 USA. NR 13 TC 34 Z9 36 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 8 PY 2000 VL 76 IS 19 BP 2788 EP 2790 DI 10.1063/1.126476 PG 3 WC Physics, Applied SC Physics GA 309QB UT WOS:000086778200048 ER PT J AU Bridges, AS Dorcas, ME AF Bridges, AS Dorcas, ME TI Temporal variation in anuran calling behavior: Implications for surveys and monitoring programs SO COPEIA LA English DT Article ID FROGS AB Recent awareness of amphibian declines has raised the need for effective monitoring programs. Call surveys are a standard approach to monitoring populations of most anuran species. Temporal variation in calling activity, however, may result in failure to detect some species. Automated recording systems (ARS) allow consistent sampling for extended periods with little or no disturbance to calling anurans. We used an ARS to measure temporal variation in anuran calling activity during the summer of 1997 at a Carolina bay on the U.S. Department of Energy's Savannah River Site, South Carolina. We documented considerable interspecific variation in calling activity, a phenomenon that, using traditional call survey techniques, would result in failure to detect some species. In particular, we found that Southern Leopard Frogs (Rana sphenocephala), thought to breed only in early spring and fall in the region, called consistently from midnight until dawn during July. Because protocols for most call surveys dictate that the listener survey only during early evening hours, most call surveys would not detect the presence of this species. Our results indicate that temporal variation in anuran calling activity warrants further investigation and should be considered when developing anuran monitoring programs. C1 Savannah River Ecol Lab, Aiken, SC 29803 USA. Davidson Coll, Dept Biol, Davidson, NC 28036 USA. RP Bridges, AS (reprint author), Savannah River Ecol Lab, Drawer E, Aiken, SC 29803 USA. NR 19 TC 81 Z9 87 U1 3 U2 20 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD MAY 8 PY 2000 IS 2 BP 587 EP 592 DI 10.1643/0045-8511(2000)000[0587:TVIACB]2.0.CO;2 PG 6 WC Zoology SC Zoology GA 314KU UT WOS:000087055600031 ER PT J AU Garza, J Nichols, JA Dixon, DA AF Garza, J Nichols, JA Dixon, DA TI The optimized effective potential and the self-interaction correction in density functional theory: Application to molecules SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID AB-INITIO; EXCITATION-ENERGIES; EXCHANGE-ENERGY; NEGATIVE-IONS; HARTREE-FOCK; BASIS-SETS; SYSTEMS; HYDROGEN; STATES; APPROXIMATIONS AB The Krieger, Li, and Iafrate approximation to the optimized effective potential including the self-interaction correction for density functional theory has been implemented in a molecular code, NWChem, that uses Gaussian functions to represent the Kohn and Sham spin-orbitals. The differences between the implementation of the self-interaction correction in codes where planewaves are used with an optimized effective potential are discussed. The importance of the localization of the spin-orbitals to maximize the exchange-correlation of the self-interaction correction is discussed. We carried out exchange-only calculations to compare the results obtained with these approximations, and those obtained with the local spin density approximation, the generalized gradient approximation and Hartree-Fock theory. Interesting results for the energy difference (GAP) between the highest occupied molecular orbital, HOMO, and the lowest unoccupied molecular orbital, LUMO, (spin-orbital energies of closed shell atoms and molecules) using the optimized effective potential and the self-interaction correction have been obtained. The effect of the diffuse character of the basis set on the HOMO and LUMO eigenvalues at the various levels is discussed. Total energies obtained with the optimized effective potential and the self-interaction correction show that the exchange energy with these approximations is overestimated and this will be an important topic for future work. (C) 2000 American Institute of Physics. [S0021-9606(00)30114-3]. C1 Univ Autonoma Metropolitana Iztapalapa, Dept Quim, Div Ciencias Basicas & Ingn, Mexico City 09340, DF, Mexico. Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Univ Autonoma Metropolitana Iztapalapa, Dept Quim, Div Ciencias Basicas & Ingn, AP 55-534, Mexico City 09340, DF, Mexico. EM david.dixon@pnl.gov RI Garza, Jorge/H-9395-2016; Garza-Olguin, Jorge/N-3106-2016; OI Garza, Jorge/0000-0003-4249-6078; Garza-Olguin, Jorge/0000-0003-4249-6078; Nichols, Jeffrey/0000-0001-5454-9726 NR 78 TC 86 Z9 86 U1 0 U2 10 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 2000 VL 112 IS 18 BP 7880 EP 7890 DI 10.1063/1.481421 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 307DH UT WOS:000086617600016 ER PT J AU La Violette, RA Budzien, JL Stillinger, FH AF La Violette, RA Budzien, JL Stillinger, FH TI Inherent structure of a molten salt SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LOCAL ORDER; PHASE SEPARATION; STATISTICAL GEOMETRY; MOLECULAR-DYNAMICS; PARTICLE PACKINGS; ZINC-CHLORIDE; LIQUIDS; SCATTERING; ZNCL2; MODEL AB We calculated the inherent structure of a model melt of zinc (II) bromide over a wide range of densities. Stable, metastable, and unstable branches were obtained for the zero temperature pressure-volume isotherm of the inherent structure. The pressure-volume isotherm, the void distribution, and the structure factor were used to identify the spinodal, independent of any model equation of state. (C) 2000 American Institute of Physics. [S0021- 9606(00)50118-4]. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. Bell Labs, Murray Hill, NJ 07974 USA. RP La Violette, RA (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. RI Budzien, Joanne/E-8315-2011 NR 64 TC 16 Z9 16 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 8 PY 2000 VL 112 IS 18 BP 8072 EP 8078 DI 10.1063/1.481406 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 307DH UT WOS:000086617600034 ER PT J AU Ohta, S AF Ohta, S TI RIKEN-BNL Research Center SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT KEK-Tanashi International Symposium on Physics of Hadrons and Nuclei CY DEC 14-17, 1998 CL UNIV TOKYO, TOKYO, JAPAN SP Univ Tokyo, Ctr Nucl Study, Tanashi Branch High Energy Accelerat Res Organizat, Minist Educ, Sci, Culture & Sports, Japanese Soc Promot Sci, Inst Phys & Chem Res, Univ Tcl Study HO UNIV TOKYO ID CHIRAL FERMIONS; LATTICE; QCD; NUCLEON AB RIKEN-BNL Research Center came into existence in the fall of 1997. It is dedicated to the strong interaction physics and aims at promoting young researchers. It has been leading the RHIC and RHIC-Spin researches, revolutionized the cascade models for relativistic heavy-ion collisions, built the world's fastest non-commercial supercomputer, and is pioneering the lattice-QCD numerical calculations with exact chiral symmetry. C1 KEK, High Energy Accelerator Res Org, Inst Particle & Nucl Studies, Tsukuba, Ibaraki 3050801, Japan. Brookhaven Natl Lab, RIKEN BNL Res Ctr, Upton, NY 11973 USA. RP Ohta, S (reprint author), KEK, High Energy Accelerator Res Org, Inst Particle & Nucl Studies, Tsukuba, Ibaraki 3050801, Japan. NR 80 TC 0 Z9 0 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 MAY 8 PY 2000 VL 670 BP 22C EP 31C DI 10.1016/S0375-9474(00)00064-6 PG 10 WC Physics, Nuclear SC Physics GA 312ZZ UT WOS:000086975000004 ER PT J AU Oset, E Oller, JA Pelaez, JR Ramos, A Chiang, HC Guerrero, F Hirenzaki, S Lee, TSH Marco, E Nacher, JC Okumura, Y Parreno, A Toki, H Vicente-Vacas, M AF Oset, E Oller, JA Pelaez, JR Ramos, A Chiang, HC Guerrero, F Hirenzaki, S Lee, TSH Marco, E Nacher, JC Okumura, Y Parreno, A Toki, H Vicente-Vacas, M TI Recent progress on the chiral unitary approach to meson meson and meson baryon interactions SO NUCLEAR PHYSICS A LA English DT Article; Proceedings Paper CT KEK-Tanashi International Symposium on Physics of Hadrons and Nuclei CY DEC 14-17, 1998 CL UNIV TOKYO, TOKYO, JAPAN SP Univ Tokyo, Ctr Nucl Study, Tanashi Branch High Energy Accelerat Res Organizat, Minist Educ, Sci, Culture & Sports, Japanese Soc Promot Sci, Inst Phys & Chem Res, Univ Tcl Study HO UNIV TOKYO ID PERTURBATION-THEORY; NONPERTURBATIVE APPROACH; NUCLEAR-MATTER; ONE-LOOP; PI-PI; SCATTERING; ISOSCALAR; DYNAMICS; CHANNELS; DECAY AB We report on recent progress on the chiral unitary approach, analogous to the effective range expansion in Quantum Mechanics, which is shown to have a much larger convergence radius than ordinary chiral perturbation theory, allowing one to reproduce data for meson meson interaction up to 1.2 GeV. Applications to physical processes so far unsuited for a standard chiral perturbative approach are presented. Results for the extension of these ideas to the meson baryon sector are discussed, together with applications to kaons in a nuclear medium and K- atoms. C1 Osaka Univ, Nucl Phys Res Ctr, Osaka, Japan. Univ Valencia, Ctr Mixto, Dept Fis Teor, E-46003 Valencia, Spain. Univ Valencia, Ctr Mixto, IFIC, E-46003 Valencia, Spain. Univ Complutense Madrid, Dept Fis Teor, E-28040 Madrid, Spain. Univ Barcelona, Dept Estructura & Constituents Mat, E-08007 Barcelona, Spain. Acad Sinica, Inst High Energy Phys, Beijing, Peoples R China. Nara Womens Univ, Dept Phys, Nara, Japan. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Washington, Inst Nucl Theory, Seattle, WA 98195 USA. RP Oset, E (reprint author), Osaka Univ, Nucl Phys Res Ctr, Osaka, Japan. RI Marco, Eugenio/F-4583-2011; Vicente Vacas, Manuel Jose/K-4326-2014; Pelaez, Jose/K-9767-2014; Ramos, Angels/L-3043-2014 OI Vicente Vacas, Manuel Jose/0000-0001-7266-5480; Pelaez, Jose/0000-0003-0737-4681; Ramos, Angels/0000-0002-0882-1570 NR 37 TC 1 Z9 1 U1 0 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 MAY 8 PY 2000 VL 670 BP 111C EP 118C DI 10.1016/S0375-9474(00)00080-4 PG 8 WC Physics, Nuclear SC Physics GA 312ZZ UT WOS:000086975000020 ER PT J AU Cheng, HC Dobrescu, BA Hill, CT AF Cheng, HC Dobrescu, BA Hill, CT TI Gauge coupling unification with extra dimensions and gravitational scale effects SO NUCLEAR PHYSICS B LA English DT Article ID SUPERSYMMETRIC STANDARD MODEL; ELECTROWEAK SYMMETRY-BREAKING; FLAVOR-UNIVERSAL COLORONS; KALUZA-KLEIN EXCITATIONS; GRAND UNIFIED THEORIES; PRECISION CORRECTIONS; TOP-QUARK; MASS; TEV; PHENOMENOLOGY AB We study gauge coupling unification in the presence of extra dimensions compactified at a few TeV. Achieving unification requires a large number of gauge boson Kaluza-Klein excitations lighter than the string scale, such that the higher-dimensional gauge couplings are partial derivative(1) in string scale units. Corrections to the gauge couplings from two or more loops are about 10% or larger, hence string (or M) theory is generally expected to be strongly coupled in similar to TeV-scale extra-dimensional scenarios. Higher-dimensional operators induced by quantum gravitational effects can shift the gauge couplings by a few percent. These effects are sufficiently large that even the minimal Standard Model, or the MSSM, allow unification at a scale in the similar to TeV range. The strongly coupled unified theory may induce dynamical electroweak symmetry breaking. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Chicago, IL 60510 USA. RP Cheng, HC (reprint author), Fermi Natl Accelerator Lab, POB 500, Batavia, IL 60510 USA. NR 68 TC 25 Z9 25 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0550-3213 J9 NUCL PHYS B JI Nucl. Phys. B PD MAY 8 PY 2000 VL 573 IS 3 BP 597 EP 616 DI 10.1016/S0550-3213(99)00816-0 PG 20 WC Physics, Particles & Fields SC Physics GA 309FF UT WOS:000086757100001 ER PT J AU Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Hill, TS Lange, DJ Morrison, RJ Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T AF Artuso, M Ayad, R Boulahouache, C Bukin, K Dambasuren, E Karamov, S Kopp, S Majumder, G Moneti, GC Mountain, R Schuh, S Skwarnicki, T Stone, S Viehhauser, G Wang, JC Wolf, A Wu, J Csorna, SE Danko, I McLean, KW Marka, S Xu, Z Godang, R Kinoshita, K Lai, IC Schrenk, S Bonvicini, G Cinabro, D Perera, LP Zhou, GJ Eigen, G Lipeles, E Schmidtler, M Shapiro, A Sun, WM Weinstein, AJ Wurthwein, F Jaffe, DE Masek, G Paar, HP Potter, EM Prell, S Sharma, V Asner, DM Eppich, A Hill, TS Lange, DJ Morrison, RJ Briere, RA Behrens, BH Ford, WT Gritsan, A Roy, J Smith, JG Alexander, JP Baker, R Bebek, C Berger, BE Berkelman, K Blanc, F Boisvert, V Cassel, DG Dickson, M Drell, PS Ecklund, KM Ehrlich, R Foland, AD Gaidarev, P Gibbons, L Gittelman, B Gray, SW Hartill, DL Heltsley, BK Hopman, PI Jones, CD Kreinick, DL Lohner, M Magerkurth, A Meyer, TO Mistry, NB Nordberg, E Patterson, JR Peterson, D Riley, D Thayer, JG Thies, PG Valant-Spaight, B Warburton, A Avery, P Prescott, C Rubiera, AI Yelton, J Zheng, J Brandenburg, G Ershov, A Gao, YS Kim, DYJ Wilson, R Browder, TE Li, Y Rodriguez, JL Yamamoto, H Bergfeld, T Eisenstein, BI Ernst, J Gladding, GE Gollin, GD Hans, RM Johnson, E Karliner, I Marsh, MA Palmer, M Plager, C Sedlack, C Selen, M Thaler, JJ Williams, J Edwards, KW Janicek, R Patel, PM Sadoff, AJ Ammar, R Bean, A Besson, D Davis, R Kwak, N Zhao, X Anderson, S Frolov, VV Kubota, Y Lee, SJ Mahapatra, R O'Neill, JJ Poling, R Riehle, T Smith, A Urheim, J Ahmed, S Alam, MS Athar, SB Jian, L Ling, L Mahmood, AH Saleem, M Timm, S Wappler, F Anastassov, A Duboscq, JE Gan, KK Gwon, C Hart, T Honscheid, K Hufnagel, D Kagan, H Kass, R Pedlar, TK Schwarthoff, H Thayer, JB von Toerne, E Zoeller, MM Richichi, SJ Severini, H Skubic, P Undrus, A Chen, S Fast, J Hinson, JW Lee, J Menon, N Miller, DH Shibata, EI Shipsey, IPJ Pavlunin, V Cronin-Hennessy, D Kwon, Y Lyon, AL Thorndike, EH Jessop, CP Marsiske, H Perl, ML Savinov, V Ugolini, D Zhou, X Coan, TE Fadeyev, V Maravin, Y Narsky, I Stroynowski, R Ye, J Wlodek, T TI Search for the decay (B)over-bar(0) -> D*(0)gamma SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARTICLE PHYSICS; DETECTOR; MESONS AB We report results of a search for the rare radiative decay (B) over bar(0) --> D*(0)gamma. Using 9.66 x 10(6) meson pairs collected with the CLEO detector at the Cornell Electron Storage Ring, we set an upper limit on the branching ratio for this decay of 5.0 x 10(-5) at 90% C.L. This provides evidence that the anomalous enhancement is absent in W-exchange processes and that weak radiative B decays are dominated by the short-distance b --> s gamma mechanism in the standard model. C1 Syracuse Univ, Syracuse, NY 13244 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Wayne State Univ, Detroit, MI 48202 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. Univ Colorado, Boulder, CO 80309 USA. Cornell Univ, Ithaca, NY 14853 USA. Univ Florida, Gainesville, FL 32611 USA. Harvard Univ, Cambridge, MA 02138 USA. Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Illinois, Urbana, IL 61801 USA. Carleton Univ, Ottawa, ON K1S 5B6, Canada. McGill Univ, Montreal, PQ H3A 2T8, Canada. Ithaca Coll, Ithaca, NY 14850 USA. Univ Kansas, Lawrence, KS 66045 USA. Univ Minnesota, Minneapolis, MN 55455 USA. SUNY Albany, Albany, NY 12222 USA. Ohio State Univ, Columbus, OH 43210 USA. Univ Oklahoma, Norman, OK 73019 USA. Purdue Univ, W Lafayette, IN 47907 USA. Univ Rochester, Rochester, NY 14627 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. So Methodist Univ, Dallas, TX 75275 USA. RP Artuso, M (reprint author), Syracuse Univ, Syracuse, NY 13244 USA. RI Warburton, Andreas/N-8028-2013; Briere, Roy/N-7819-2014 OI Warburton, Andreas/0000-0002-2298-7315; Briere, Roy/0000-0001-5229-1039 NR 19 TC 5 Z9 5 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 MAY 8 PY 2000 VL 84 IS 19 BP 4292 EP 4295 DI 10.1103/PhysRevLett.84.4292 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600010 ER PT J AU Abe, K Abe, K Abe, T Adam, I Akimoto, H Aston, D Baird, KG Baltay, C Band, HR Barklow, TL Bauer, JM Bellodi, G Berger, R Blaylock, G Bogart, JR Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Calcaterra, A Cassell, R Chou, A Cohn, HO Coller, JA Convery, MR Cook, V Cowan, RF Crawford, G Damerell, CJS Daoudi, M Dasu, S de Groot, N de Sangro, R Dong, DN Doser, M Dubois, R Erofeeva, I Eschenberg, V Etzion, E Fahey, S Falciai, D Fernandez, JP Flood, K Frey, R Hart, EL Hasuko, K Hertzbach, SS Huffer, ME Huynh, X Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Kajikawa, R Kalelkar, M Kang, H Kofler, RR Kroeger, RS Langston, M Leith, DWG Lia, V Lin, C Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T McKemey, AK Messner, R Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Narita, S Nauenberg, U Nesom, G Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, CH Peruzzi, I Piccolo, M Piemontese, L Plano, RJ Prepost, R Prescott, CY Ratcliff, BN Reidy, J Reinertsen, PL Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schumm, BA Schwiening, J Serbo, VV Shapiro, G Sinev, NB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, H Su, D Suekane, F Sugiyama, A Swartz, M Taylor, FE Thom, J Usher, T Va'vra, J Verdier, R Wagner, DL Waite, AP Walston, S Wang, J Weidemann, AW Weiss, ER Whitaker, JS Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, H Wright, TR Yamamoto, RK Yashima, J Yellin, SJ Young, CC Yuta, H AF Abe, K Abe, K Abe, T Adam, I Akimoto, H Aston, D Baird, KG Baltay, C Band, HR Barklow, TL Bauer, JM Bellodi, G Berger, R Blaylock, G Bogart, JR Bower, GR Brau, JE Breidenbach, M Bugg, WM Burke, D Burnett, TH Burrows, PN Calcaterra, A Cassell, R Chou, A Cohn, HO Coller, JA Convery, MR Cook, V Cowan, RF Crawford, G Damerell, CJS Daoudi, M Dasu, S de Groot, N de Sangro, R Dong, DN Doser, M Dubois, R Erofeeva, I Eschenberg, V Etzion, E Fahey, S Falciai, D Fernandez, JP Flood, K Frey, R Hart, EL Hasuko, K Hertzbach, SS Huffer, ME Huynh, X Iwasaki, M Jackson, DJ Jacques, P Jaros, JA Jiang, ZY Johnson, AS Johnson, JR Kajikawa, R Kalelkar, M Kang, H Kofler, RR Kroeger, RS Langston, M Leith, DWG Lia, V Lin, C Mancinelli, G Manly, S Mantovani, G Markiewicz, TW Maruyama, T McKemey, AK Messner, R Moffeit, KC Moore, TB Morii, M Muller, D Murzin, V Narita, S Nauenberg, U Nesom, G Oishi, N Onoprienko, D Osborne, LS Panvini, RS Park, CH Peruzzi, I Piccolo, M Piemontese, L Plano, RJ Prepost, R Prescott, CY Ratcliff, BN Reidy, J Reinertsen, PL Rochester, LS Rowson, PC Russell, JJ Saxton, OH Schalk, T Schumm, BA Schwiening, J Serbo, VV Shapiro, G Sinev, NB Snyder, JA Staengle, H Stahl, A Stamer, P Steiner, H Su, D Suekane, F Sugiyama, A Swartz, M Taylor, FE Thom, J Usher, T Va'vra, J Verdier, R Wagner, DL Waite, AP Walston, S Wang, J Weidemann, AW Weiss, ER Whitaker, JS Williams, SH Willocq, S Wilson, RJ Wisniewski, WJ Wittlin, JL Woods, H Wright, TR Yamamoto, RK Yashima, J Yellin, SJ Young, CC Yuta, H TI Precise measurement of the b-quark fragmentation function in Z(0) boson decays SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEAVY QUARKS; E+E ANNIHILATION; QCD; MESONS; PARAMETERS; HADRONS; MODEL AB We have developed a new technique for inclusive reconstruction of the energy of B hadrons. The excellent efficiency and resolution of this technique allow us to make the must precise determination of the b-quark fragmentation function, using e(+)e(-) --> Z(0) decays recorded in the SLAG Large Detector experiment. We compared our measurement with the predictions of a number of fragmentation models. We excluded several of these models and measured the average scaled energy of weakly decaying B hadrons to be [x(B)] = 0.714 +/- 0.005(stat) +/- 0.007(syst) +/- 0.002 (model dependence). C1 Univ Bristol, Bristol, Avon, England. Brunel Univ, Uxbridge UB8 3PH, Middx, England. Boston Univ, Boston, MA 02215 USA. Univ Colorado, Boulder, CO 80309 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Univ Ferrara, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Sezione Ferrara, I-44100 Ferrara, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Johns Hopkins Univ, Baltimore, MD 21218 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Massachusetts, Amherst, MA 01003 USA. Univ Mississippi, University, MS 38677 USA. MIT, Cambridge, MA 02139 USA. Moscow State Univ, Inst Phys Nucl, Moscow, Russia. Nagoya Univ, Chikusa Ku, Nagoya, Aichi 464, Japan. Univ Oregon, Eugene, OR 97403 USA. Univ Oxford, Oxford OX1 3RH, England. Ist Nazl Fis Nucl, Sezione Perugia, I-06100 Perugia, Italy. Univ Perugia, I-06100 Perugia, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Rutgers State Univ, Piscataway, NJ 08855 USA. Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Soongsil Univ, Seoul 156743, South Korea. Univ Tennessee, Knoxville, TN 37996 USA. Tohoku Univ, Sendai, Miyagi 980, Japan. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Vanderbilt Univ, Nashville, TN 37235 USA. Univ Washington, Seattle, WA 98105 USA. Univ Wisconsin, Madison, WI 53706 USA. Yale Univ, New Haven, CT 06511 USA. RI de Groot, Nicolo/A-2675-2009; Stahl, Achim/E-8846-2011; de Sangro, Riccardo/J-2901-2012; Calcaterra, Alessandro/P-5260-2015; Frey, Raymond/E-2830-2016 OI Stahl, Achim/0000-0002-8369-7506; de Sangro, Riccardo/0000-0002-3808-5455; Calcaterra, Alessandro/0000-0003-2670-4826; Frey, Raymond/0000-0003-0341-2636 NR 33 TC 46 Z9 46 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4300 EP 4304 DI 10.1103/PhysRevLett.84.4300 PG 5 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600012 ER PT J AU Schaffner-Bielich, J Mattiello, R Sorge, H AF Schaffner-Bielich, J Mattiello, R Sorge, H TI Dibaryons with strangeness: Their weak nonleptonic decay using SU(3) symmetry and how to find them in relativistic heavy-ion collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID ENERGY NUCLEAR COLLISIONS; PB COLLISIONS; QUARK MATTER; H-DIBARYON; SEARCH; GEV/C; MODEL; HYPERNUCLEI; DEUTERONS; PARTICLE AB Weak SU(3) symmetry is successfully applied to the weak hadronic decay amplitudes of octet hyperons. Weak nonmesonic and mesonic decays of various dibaryons with strangeness, their dominant decay modes, and lifetimes are calculated. Production estimates for the Brookhaven Relativistic Heavy Ion Collider are presented employing wave-function coalescence. Signals for detecting strange dibaryon states in heavy-ion collisions and revealing information about the unknown hyperon-hyperon interactions are outlined. C1 Brookhaven Natl Lab, RIKEN, Res Lab, Upton, NY 11973 USA. Niels Bohr Inst, DK-2100 Copenhagen, Denmark. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RP Schaffner-Bielich, J (reprint author), Brookhaven Natl Lab, RIKEN, Res Lab, Upton, NY 11973 USA. NR 45 TC 39 Z9 39 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 MAY 8 PY 2000 VL 84 IS 19 BP 4305 EP 4308 DI 10.1103/PhysRevLett.84.4305 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600013 ER PT J AU Krasnitz, A Venugopalan, R AF Krasnitz, A Venugopalan, R TI Initial energy density of gluons produced in very-high-energy nuclear collisions SO PHYSICAL REVIEW LETTERS LA English DT Article ID WILSON RENORMALIZATION-GROUP; WEIZSACKER-WILLIAMS FIELD; HEAVY-ION COLLISIONS; SMALL-X; TRANSVERSE-MOMENTUM; MINIJET PRODUCTION; PARTON PRODUCTION; RADIATION; DISTRIBUTIONS; QUARK AB In very-high-energy nuclear collisions, the initial energy of produced gluons per unit area per unit rapidity, (dE/L-2)/d eta, is equal to f(g(2) mu L)(g(2) mu)(3)/g(2), where mu(2) is proportional to the gluon density per unit area of the colliding nuclei. For an SU(2) gauge theory, a nonperturbative computation of f(g(2) mu L) shows that it varies rapidly for small g(2) mu L. but varies only by similar to 25%, from 0.208 +/- 0.004 to 0.257 +/- 0.005, for a wide range 35.36-296.98 in g(2) mu L. This includes the range relevant for collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). Extrapolating to SU(3), we estimate dE/d eta for Au-Au collisions in the central region at RHIC and LHC. C1 Univ Algarve, Unidad Ciencias Exactas & Humanas, P-8000 Faro, Portugal. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Krasnitz, A (reprint author), Univ Algarve, Unidad Ciencias Exactas & Humanas, Campus Gambelas, P-8000 Faro, Portugal. NR 41 TC 260 Z9 260 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4309 EP 4312 DI 10.1103/PhysRevLett.84.4309 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600014 ER PT J AU Kendrick, BK Jayasinghe, L Moser, S Auzinsh, M Shafer-Ray, N AF Kendrick, BK Jayasinghe, L Moser, S Auzinsh, M Shafer-Ray, N TI Observation of predicted resonance structure in the H+D-2 -> HD(v '=0,j '=7)+D reaction at a collision energy of 0.94 eV SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM REACTIVE SCATTERING; KOHN VARIATIONAL PRINCIPLE; INTEGRAL CROSS-SECTIONS; S-MATRIX VERSION; H+H2 REACTION; DYNAMICAL RESONANCES; CHEMICAL-REACTIONS; PROBABILITIES; SURFACE AB We present experimental verification of predicted resonance structure in the energy dependence of the H + D-2 reaction. Specifically we predict and observe a broad resonance in the H + D-2 --> HD(upsilon' = 0,j' = 7) + D reaction at a collision energy of 0.94 eV. This resonance structure is roughly Gaussian with a full width at half maximum of 0.1 eV. These results represent the first experimentally observed resonance structure in the fundamental H + H-2 reaction system. C1 Univ Calif Los Alamos Natl Lab, Theoret Div T12, Los Alamos, NM 87545 USA. Univ Oklahoma, Dept Phys & Astron, Norman, OK 73019 USA. RP Kendrick, BK (reprint author), Univ Calif Los Alamos Natl Lab, Theoret Div T12, MS-B268, Los Alamos, NM 87545 USA. NR 27 TC 36 Z9 37 U1 1 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 MAY 8 PY 2000 VL 84 IS 19 BP 4325 EP 4328 DI 10.1103/PhysRevLett.84.4325 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600018 ER PT J AU Garcia-Pablos, D Sigalas, M de Espinosa, FRM Torres, M Kafesaki, M Garcia, N AF Garcia-Pablos, D Sigalas, M de Espinosa, FRM Torres, M Kafesaki, M Garcia, N TI Theory and experiments on elastic band gaps SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPHERICAL CAVITIES; PHOTONIC CRYSTAL; WAVE; STATES; TRANSMISSION; LOCALIZATION; COMPOSITES; SURFACE; MEDIA AB We study elastic band gaps in nonhomogeneous periodic finite media. we study elastic band gaps In nonhomogeneous periodic finite media. The finite-difference time-domain method is used for the first time in the field of elastic band-gap materials. It is used to interpret experimental data for two-dimensional systems consisting of cylinders of fluids (Hg, air, and oil) inserted periodically in a finite slab of aluminum host. The method provides good convergence, can be applied to realistic finite composite slabs, even to composites with a huge contrast in the elastic parameters of their components, and describes well the experiments. C1 CSIC, Lab Fis Sistemas Pequenos & Nanotecnol, Madrid 28006, Spain. Iowa State Univ Sci & Technol, Ames Lab, Ames, IA 50011 USA. CSIC, Inst Acust, Madrid 28006, Spain. CSIC, Inst Fis, Madrid 28006, Spain. RP Garcia-Pablos, D (reprint author), CSIC, Lab Fis Sistemas Pequenos & Nanotecnol, Serrano 144, Madrid 28006, Spain. RI Kafesaki, Maria/E-6843-2012 OI Kafesaki, Maria/0000-0002-9524-2576 NR 26 TC 162 Z9 178 U1 1 U2 28 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 MAY 8 PY 2000 VL 84 IS 19 BP 4349 EP 4352 DI 10.1103/PhysRevLett.84.4349 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600024 ER PT J AU Prestridge, K Vorobieff, P Rightley, PM Benjamin, RF AF Prestridge, K Vorobieff, P Rightley, PM Benjamin, RF TI Validation of an instability growth model using particle image velocimetry measurements SO PHYSICAL REVIEW LETTERS LA English DT Article ID THIN FLUID LAYER; RICHTMYER-MESHKOV INSTABILITY; GAS-CURTAIN; DRIVEN; SIMULATION; TRANSITION; TURBULENCE; EVOLUTION; PATTERNS AB A varicose-profile, thin layer of heavy gas (SF6) in lighter gas lair) is impulsively accelerated by a planar, Mach 1.2 shock, producing the Richtmyer-Meshkov instability. We present the first measurements of the circulation in the curtain during the vortex-dominated, nonlinear stage of the instability evolution. These measurements, based on particle image velocimetry data, are employed to validate an idealized model of the nonlinear perturbation growth. C1 Univ Calif Los Alamos Natl Lab, Dynam Experimentat Div, Los Alamos, NM 87545 USA. Univ New Mexico, Dept Engn Mech, Albuquerque, NM 87131 USA. RP Prestridge, K (reprint author), Univ Calif Los Alamos Natl Lab, Dynam Experimentat Div, Los Alamos, NM 87545 USA. RI Vorobieff, Peter/B-3376-2011; Prestridge, Kathy/C-1137-2012 OI Prestridge, Kathy/0000-0003-2425-5086 NR 21 TC 29 Z9 31 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 MAY 8 PY 2000 VL 84 IS 19 BP 4353 EP 4356 DI 10.1103/PhysRevLett.84.4353 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600025 ER PT J AU Rescigno, TN AF Rescigno, TN TI Modeling hot, dense hydrogen with a classical spin dependent Hamiltonian SO PHYSICAL REVIEW LETTERS LA English DT Article ID COMPRESSED LIQUID DEUTERIUM; MOLECULAR-DYNAMICS; EQUATION; STATE; DISSOCIATION; TRANSITION AB Hot, dense hydrogen is studied with a classical model in which the interaction energy between atoms depends on their internal spins as well as their separation distance. The spins are treated as classical variables. This model is used in Monte Carlo simulations to calculate internal energies, pressures, and Fair correlation functions, as well as the Hugoniot for shocked liquid deuterium. The results clearly show the transition of hot, dense hydrogen from a molecular to an atomic fluid. Our results are in reasonable agreement with far more elaborate quantum mechanical simulations. C1 Univ Calif Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA 94551 USA. RP Rescigno, TN (reprint author), Univ Calif Lawrence Livermore Natl Lab, Phys Directorate, Livermore, CA 94551 USA. NR 22 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 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4377 EP 4380 DI 10.1103/PhysRevLett.84.4377 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600031 ER PT J AU Tostmann, H DiMasi, E Shpyrko, OG Pershan, PS Ocko, BM Deutsch, M AF Tostmann, H DiMasi, E Shpyrko, OG Pershan, PS Ocko, BM Deutsch, M TI Microscopic structure of the wetting film at the surface of liquid Ga-Bi alloys SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY REFLECTIVITY; CRITICAL-POINT; INTERFACES; GALLIUM AB X-ray reflectivity measurements of the binary liquid Ca-Bi alloy reveal a dramatically different surface structure above and below the monotectic temperature T-mono = 222 degrees C. A Gibbs-adsorbed Bi monolayer resides at the surface in both regimes. However, a 30 Angstrom thick, Bi-rich wetting film intrudes between the Bi monolayer and the Ga-rich bulk for T > T-mono. The wetting film's internal structure, not hitherto measured, is determined with Angstrom resolution, showing a concentration gradient not predicted by theory and a highly diffuse interface with the bulk phase. C1 Harvard Univ, Div Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Bar Ilan Univ, Dept Phys, IL-52100 Ramat Gan, Israel. RP Tostmann, H (reprint author), Harvard Univ, Div Appl Sci, Cambridge, MA 02138 USA. RI Shpyrko, Oleg/J-3970-2012 NR 20 TC 55 Z9 58 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4385 EP 4388 DI 10.1103/PhysRevLett.84.4385 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600033 ER PT J AU Gomez, L Slutzky, C Ferron, J de la Figuera, J Camarero, J de Parga, ALV de Miguel, JJ Miranda, R AF Gomez, L Slutzky, C Ferron, J de la Figuera, J Camarero, J de Parga, ALV de Miguel, JJ Miranda, R TI Novel microscopic mechanism of intermixing during growth on soft metallic substrates SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCANNING-TUNNELING-MICROSCOPY; ALLOY FORMATION; EPITAXIAL-GROWTH; ULTRATHIN FILMS; SURFACE ALLOYS; DEPOSITION; CU(111); DIFFUSION; ENERGIES; SYSTEMS AB Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands. C1 Inst Fis Rosario, Fac Ciencias Exactas Ingn & Agrimensura, RA-2000 Rosario, Santa Fe, Argentina. Univ Nacl Litoral, CONICET, FIQ, INTEC,Grp Fis, RA-3000 Santa Fe, Argentina. Sandia Natl Labs, Livermore, CA 94551 USA. Univ Autonoma Madrid, Dept Fis Mat Condensada, E-28049 Madrid, Spain. Univ Autonoma Madrid, Inst Ciencia Mat Nicolas Cabrera, E-28049 Madrid, Spain. RP Gomez, L (reprint author), Inst Fis Rosario, Fac Ciencias Exactas Ingn & Agrimensura, RA-2000 Rosario, Santa Fe, Argentina. RI de la Figuera, Juan/E-7046-2010; de Miguel, Juan J./A-5183-2008; Ferron, Julio/A-7434-2010; Vazquez de Parga, Amadeo/L-2418-2013; Camarero, Julio/C-4375-2014; OI de la Figuera, Juan/0000-0002-7014-4777; de Miguel, Juan J./0000-0003-0122-7605; Vazquez de Parga, Amadeo/0000-0003-0551-1603; Camarero De Diego, Julio/0000-0003-0078-7280 NR 31 TC 29 Z9 29 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 MAY 8 PY 2000 VL 84 IS 19 BP 4397 EP 4400 DI 10.1103/PhysRevLett.84.4397 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600036 ER PT J AU Dexheimer, SL Van Pelt, AD Brozik, JA Swanson, BI AF Dexheimer, SL Van Pelt, AD Brozik, JA Swanson, BI TI Femtosecond vibrational dynamics of self-trapping in a quasi-one-dimensional system SO PHYSICAL REVIEW LETTERS LA English DT Article ID VALENCE METAL-COMPLEXES; NONLINEAR LATTICE-RELAXATION; IMPULSIVE STIMULATED SCATTERING; CHARGE-TRANSFER EXCITATION; GROUND-STATE; SPECTROSCOPY; EXCITON; CHAIN; BACTERIORHODOPSIN; LUMINESCENCE AB We have directly time resolved the lattice motions associated with the formation of the self-trapped exciton in the quasi-one-dimensional system [Pt(en)(2)] [Pt(en)(2)Br-2].(PF6)(4) (en = ethylene-diamine. C2H8N2), using femtosecond impulsive excitation techniques. A strongly damped, low-frequency wave packet modulation at similar to 110 cm(-1) accompanies the formation of the self-trapped exciton on a similar to 200 fs time scale following excitation of the intervalence charge-transfer transition. Coherent oscillations at the ground state vibrational frequency and its harmonics are also detected. C1 Washington State Univ, Dept Phys, Pullman, WA 99164 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Dexheimer, SL (reprint author), Washington State Univ, Dept Phys, Pullman, WA 99164 USA. NR 24 TC 66 Z9 67 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4425 EP 4428 DI 10.1103/PhysRevLett.84.4425 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600043 ER PT J AU Balatsky, AV Kumar, P Schrieffer, JR AF Balatsky, AV Kumar, P Schrieffer, JR TI Collective mode in a superconductor with mixed-symmetry order parameter components SO PHYSICAL REVIEW LETTERS LA English DT Article ID D-WAVE SUPERCONDUCTORS; T-C SUPERCONDUCTORS; SPONTANEOUS TIME-REVERSAL; D(X(2)-Y(2))-WAVE SUPERCONDUCTOR; MAGNETIC-IMPURITIES; PAIRING SYMMETRY; PARITY BREAKING; SURFACE-STATES; VORTEX; COEXISTENCE AB We consider a superconducting state with mixed-symmetry order parameter components, e.g., d + is or d + id' with d' = d(xy). We argue for the existence of a new orbital magnetization mode which corresponds to oscillations of relative phase phi between two components around an equilibrium value of phi = pi/2 It is similar to the "clapping" mode in superfluid He-3-A. we estimate the frequency of this of mode omega(0)(B, T) depending on the field and temperature for the specific case of magnetic field induced d' = d(xy) state. This mode is tunable with a magnetic field with omega(0)(B,T) proportional to B Delta(0), where Delta(0) is the magnitude of the d-wave order parameter. We also estimate the velocity s(B, T) of this mode. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Florida, Dept Phys, Gainesville, FL 32611 USA. Florida State Univ, NHMFL, Tallahassee, FL 32310 USA. RP Balatsky, AV (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 37 TC 20 Z9 20 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 MAY 8 PY 2000 VL 84 IS 19 BP 4445 EP 4448 DI 10.1103/PhysRevLett.84.4445 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600048 ER PT J AU Fretwell, HM Kaminski, A Mesot, J Campuzano, JC Norman, MR Randeria, M Sato, T Gatt, R Takahashi, T Kadowaki, K AF Fretwell, HM Kaminski, A Mesot, J Campuzano, JC Norman, MR Randeria, M Sato, T Gatt, R Takahashi, T Kadowaki, K TI Fermi surface of Bi2Sr2CaCu2O8 SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANGLE-RESOLVED PHOTOEMISSION; YBA2CU3O6.9; TOPOLOGY; BANDS AB We study the Fermi surface of Bi2Sr2CaCu2O8 using angle resolved photoemission spectroscopy (ARPES) with a momentum resolution of similar to 0.01 of the Brillouin zone. We show that, contrary to recent suggestions, the ARPES derived Fermi surface is a large hole barrel centered at (pi, pi), independent of the incident photon energy. We caution that the photon energy and k dependence of the matrix elements, if not properly accounted for, can lead to misinterpretation of ARPES intensities. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Tata Inst Fundamental Res, Mumbai 400005, India. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 305, Japan. Univ Illinois, Dept Phys, Chicago, IL 60607 USA. RP Fretwell, HM (reprint author), Univ Wales, Dept Phys, Swansea SA2 8PP, W Glam, Wales. RI Takahashi, Takashi/E-5080-2010; Sato, Takafumi/E-5094-2010; Tohoku, Arpes/A-4890-2010; Norman, Michael/C-3644-2013 NR 14 TC 77 Z9 77 U1 3 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4449 EP 4452 DI 10.1103/PhysRevLett.84.4449 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600049 ER PT J AU Guo, C Rodriguez, G Lobad, A Taylor, AJ AF Guo, C Rodriguez, G Lobad, A Taylor, AJ TI Structural phase transition of aluminum induced by electronic excitation SO PHYSICAL REVIEW LETTERS LA English DT Article ID OPTICAL-PROPERTIES; SIMPLE METAL; GOLD-FILMS; FEMTOSECOND; THERMOREFLECTIVITY; REFLECTIVITY; TEMPERATURE; COPPER; GAAS AB The dynamics of a structural phase transition induced by interband electronic excitation in aluminum is studied by determining the time evolution of the dielectric constant at 1.55 eV through the measurement of the transient reflectivity induced by an ultrafast pump pulse. The threshold fluence and the time scale for this transition are significantly less than the values necessary for ultrafast heat-induced melting, indicating that this phase change is caused by band structure collapse and lattice instability resulting from strong electronic excitation. C1 Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, Los Alamos, NM 87545 USA. RP Guo, C (reprint author), Univ Calif Los Alamos Natl Lab, Condensed Matter & Thermal Phys Grp, POB 1663, Los Alamos, NM 87545 USA. RI Rodriguez, George/G-7571-2012 OI Rodriguez, George/0000-0002-6044-9462 NR 25 TC 85 Z9 88 U1 0 U2 13 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAY 8 PY 2000 VL 84 IS 19 BP 4493 EP 4496 DI 10.1103/PhysRevLett.84.4493 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600060 ER PT J AU Kladko, K Mitkov, I Bishop, AR AF Kladko, K Mitkov, I Bishop, AR TI Universal scaling of wave propagation failure in arrays of coupled nonlinear cells SO PHYSICAL REVIEW LETTERS LA English DT Article ID BISTABLE CHEMICAL REACTORS; CALCIUM WAVES; MODEL; DYNAMICS; SYSTEMS AB We study the onset of the propagation failure of wave fronts in systems of coupled cells. We introduce a new method to analyze the scaling of the critical external field at which fronts cease to propagate, as a function of intercellular coupling. We find the universal scaling of the field throughout the range of couplings and show that the field becomes exponentially small for large couplings. Our method is generic and applicable to a wide class of cellular dynamics in chemical, biological, and engineering systems. We confirm our results by direct numerical simulations C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RP Kladko, K (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 22 TC 33 Z9 33 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 MAY 8 PY 2000 VL 84 IS 19 BP 4505 EP 4508 DI 10.1103/PhysRevLett.84.4505 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600063 ER PT J AU Bickham, SR Kress, JD Collins, LA Stumpf, R AF Bickham, SR Kress, JD Collins, LA Stumpf, R TI Comment on "Ab initio molecular dynamics studies of off-center displacements in CuCl" - Bickham et al. reply SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Corning Inc, Corning, NY 14831 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Motorola Inc, Computat Mat Grp, Los Alamos, NM 87545 USA. RP Bickham, SR (reprint author), Corning Inc, Corning, NY 14831 USA. NR 6 TC 2 Z9 2 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 MAY 8 PY 2000 VL 84 IS 19 BP 4512 EP 4512 DI 10.1103/PhysRevLett.84.4512 PG 1 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600067 ER PT J AU Chen, SY Deng, YF Nie, XB Tu, YH AF Chen, SY Deng, YF Nie, XB Tu, YH TI Clustering kinetics of granular media in three dimensions SO PHYSICS LETTERS A LA English DT Article ID GASES AB Three-dimensional molecular dynamics simulations of dissipative particles (similar to 10(6)) art carried out for studying the clustering kinetics of granular media during cooling. The inter-connected high particle density regions are identified, showing tube-like structures. The energy decay rates as functions of the particle density and the restitution coefficient are obtained. It is found that the probability density function of the particle density obeys an exponential distribution tit late stages. Both the fluctuation of density and the mean cluster size of the particle density have power law relations against time during the inelastic coalescing process. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. IBM Corp, Div Res, Thomas J Watson Res Ctr, Yorktown Heights, NY 10598 USA. SUNY Stony Brook, Dept Appl Math & Stat, Stony Brook, NY 11794 USA. RP Chen, SY (reprint author), Univ Calif Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. RI Chen, Shiyi/A-3234-2010; OI Deng, Yuefan/0000-0002-5224-3958 NR 18 TC 13 Z9 15 U1 0 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 MAY 8 PY 2000 VL 269 IS 4 BP 218 EP 223 DI 10.1016/S0375-9601(00)00243-7 PG 6 WC Physics, Multidisciplinary SC Physics GA 318KT UT WOS:000087283700005 ER PT J AU Dellago, C Hoover, WG AF Dellago, C Hoover, WG TI Are local Lyapunov exponents continuous in phase space? (vol 268 A, pg 330, 2000) SO PHYSICS LETTERS A LA English DT Correction C1 Univ Rochester, Dept Chem, Rochester, NY 14627 USA. Univ Calif Davis, Dept Appl Sci, Livermore, CA 94551 USA. Univ Calif Lawrence Livermore Natl Lab, Methods Dev Grp, Livermore, CA 94551 USA. RP Dellago, C (reprint author), Univ Rochester, Dept Chem, Rochester, NY 14627 USA. RI Dellago, Christoph/E-1625-2011 NR 1 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 MAY 8 PY 2000 VL 269 IS 4 BP 261 EP 261 DI 10.1016/S0375-9601(00)00262-0 PG 1 WC Physics, Multidisciplinary SC Physics GA 318KT UT WOS:000087283700013 ER PT J AU Davison, BH Barton, JW Klasson, KT Francisco, AB AF Davison, BH Barton, JW Klasson, KT Francisco, AB TI Influence of high biomass concentrations on alkane solubilities SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article DE Henry's law; alkane; solubility; biofiltration; biomass; propane ID GASEOUS WASTE STREAMS; MICROBIAL REMOVAL; ORGANIC-COMPOUNDS; AIR; BIOREACTOR; CHEMICALS; KINETICS AB Alkane solubilities were measured experimentally for high-density biomass. The resulting Henry's law constants for propane were found to decrease significantly for both dense yeast suspensions and an actual propane-degrading biofilm consortium. At the biomass densities of a typical biofilm, propane solubility was about an order of magnitude greater than that in pure water. For example, a dense biofilm had a propane Henry's law constant of 0.09 +/- 0.04 atm m(3) mol(-1) compared to 0.6 +/- 0.1 atm m(3) mol(-1) measured in pure water. The results were modeled with mixing rules and compared with octanol-water mixtures. Hydrogels (agar) and salts decreased the alkane solubility. By considering a theoretical solubility of propane in dry biomass, estimates were made of intrinsic Henry's law constants for propane in pure yeast and biomass, which were 13 +/- 2 and 5 +/- 2 atm kg biomass mol-l for yeast and biofilm consortium, respectively. (C) 2000 John Wiley & Sons, inc. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Davison, BH (reprint author), Oak Ridge Natl Lab, Div Chem Technol, POB 2008, Oak Ridge, TN 37831 USA. RI Davison, Brian/D-7617-2013; OI Davison, Brian/0000-0002-7408-3609; Klasson, K. Thomas/0000-0003-3358-3081 NR 22 TC 25 Z9 27 U1 0 U2 0 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD MAY 5 PY 2000 VL 68 IS 3 BP 279 EP 284 DI 10.1002/(SICI)1097-0290(20000505)68:3<279::AID-BIT6>3.3.CO;2-G PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 304UA UT WOS:000086501500006 PM 10745196 ER PT J AU Lee, YC Curtiss, LA Ratner, MA Shriver, DF AF Lee, YC Curtiss, LA Ratner, MA Shriver, DF TI Computational studies of lithium affinities for zeolitic fragments SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ELECTRICAL RESPONSE; POLYELECTROLYTES; COMPLEXES; MIGRATION; BARRIERS; ENERGIES; BASICITY; SILICON; ETHERS; BOND AB In this Letter, we report optimized structures and lithium affinities of a series of anionic zeolitic fragments [H3Al(oCH(3))(x)(OSiH3)(1-x)(-). 2T, H2Al(OCH3)(x)(OSiH3)(2-x)(-) 3T, Al(OCH3)(x)(OSiH3)(4-x)(-) 5T] that mimic the charge sites in polyelectrolytes. Ab initio molecular orbital methods at different levels of theory are used. The lithium affinities are much larger than the corresponding sodium affinities, indicating stronger interactions between lithium cations and these zeolitic fragments. The substitution of silicon by carbon increases the lithium affinity and the effect is generally larger than in the sodium systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. Northwestern Univ, Mat Res Ctr, Evanston, IL 60208 USA. RP Curtiss, LA (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 22 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 5 PY 2000 VL 321 IS 5-6 BP 463 EP 468 DI 10.1016/S0009-2614(00)00376-6 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313YE UT WOS:000087026600020 ER PT J AU Nguyen, LH Barsky, D Erzberger, JP Wilson, DM AF Nguyen, LH Barsky, D Erzberger, JP Wilson, DM TI Mapping the protein-DNA interface and the metal-binding site of the major human apurinic/apyrimidinic endonuclease SO JOURNAL OF MOLECULAR BIOLOGY LA English DT Article DE AP endonuclease; Ape1; base excision repair; DNA binding; metal coordination ID HUMAN APURINIC ENDONUCLEASE; BASE EXCISION-REPAIR; POLYMERASE-BETA; ABASIC SITE; MOLECULAR-DYNAMICS; RNA-POLYMERASE; ACTIVE-SITE; LIGASE-III; RECOGNITION; RESIDUES AB Apurinic/apyrimidinic (AP) endonuclease Ape1 is a key enzyme in the mammalian base excision repair pathway that corrects AP sites in the genome. Ape1 cleaves the phosphodiester bond immediately 5' to AP sites through a hydrolytic reaction involving a divalent metal, co-factor. Here, site-directed mutagenesis, chemical footprinting techniques, and molecular dynamics simulations were employed to gain insights into how Ape1 interacts with its metal cation and AP DNA. It was found that Ape1 binds predominantly to the minor groove of AP DNA, and that residues R156 and Y128 contribute to protein-DNA complex stability. Furthermore, the Ape1-AP DNA footprint does not change along its reaction pathway upon active-site coordination of Mg2+ or in the presence of DNA polymerase beta (pol beta), an interactive protein partner in AP site repair. The DNA region immediately 5' to the abasic residue was determined to be in close proximity to the Ape1 metal-binding site. Experimental evidence is provided that amino acid residues E96, D70, and D308 of Ape1 are involved in metal coordination. Molecular dynamics simulations, starting from the active site of the Ape1 crystal structure, suggest that D70 and E96 bind directly to the metal, while D308 coordinates the cation through the first hydration shell. These studies define the Ape1-AP DNA interface, determine the effect of pol beta on the Ape1-DNA interaction, and reveal new insights into the Ape1 active site and overall protein dynamics. (C) 2000 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, Livermore, CA 94551 USA. RP Wilson, DM (reprint author), Univ Calif Lawrence Livermore Natl Lab, Mol & Struct Biol Div, POB 808,L-441, Livermore, CA 94551 USA. FU NCI NIH HHS [CA79056] NR 55 TC 54 Z9 54 U1 0 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-2836 J9 J MOL BIOL JI J. Mol. Biol. PD MAY 5 PY 2000 VL 298 IS 3 BP 447 EP 459 DI 10.1006/jmbi.2000.3653 PG 13 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 313DM UT WOS:000086985100009 PM 10772862 ER PT J AU Izaurralde, RC McGill, WB Rosenberg, NJ AF Izaurralde, RC McGill, WB Rosenberg, NJ TI Carbon cost of applying nitrogen fertilizer SO SCIENCE LA English DT Letter C1 Battelle Pacific NW Natl Lab, Washington, DC 20024 USA. Univ Alberta, Dept Renewable Resources, Edmonton, AB T6G 2E3, Canada. RP Izaurralde, RC (reprint author), Battelle Pacific NW Natl Lab, 901 D St SW, Washington, DC 20024 USA. RI Izaurralde, Roberto/E-5826-2012 NR 4 TC 15 Z9 17 U1 0 U2 3 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAY 5 PY 2000 VL 288 IS 5467 BP 811 EP 812 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 311DN UT WOS:000086869600018 ER PT J AU Goldbach, A Saboungi, ML Johnson, JA Cook, AR Meisel, D AF Goldbach, A Saboungi, ML Johnson, JA Cook, AR Meisel, D TI Oxidation of aqueous polyselenide solutions. A mechanistic pulse radiolysis study SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID RAMAN-SPECTROSCOPY; ELECTROLYTES; SPECIATION; SELENIUM; IONS AB The oxidation of aqueous polyselenide solutions was studied by pulse radiolysis in the presence of N2O at pH 12.3; the hydroxyl radical OH was the predominant oxidant, while hydrogen selenide anions HSe- and triselenide dianions Se-3(2-) were the major selenide species in the starting solution. The progress of the oxidation was monitored by optical spectroscopy. Transient polyselenides appeared immediately after the electron pulse and rapidly proceeded to form adducts with HSe-, i.e., HSe22- and H2Se2-, and a fairly long-lived intermediate that was identified as the diselenide radical anion Se-2(-). These radicals recombine to give eventually the tetraselenide dianion, Se-4(2-). C1 Univ Stuttgart, D-70569 Stuttgart, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Univ Notre Dame, Radiat Lab, Notre Dame, IN 46556 USA. Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA. RP Saboungi, ML (reprint author), Univ Stuttgart, Nobelstr 12, D-70569 Stuttgart, Germany. RI Saboungi, Marie-Louise/C-5920-2013; Johnson, Jacqueline/P-4844-2014; OI Saboungi, Marie-Louise/0000-0002-0607-4815; Johnson, Jacqueline/0000-0003-0830-9275; Cook, Andrew/0000-0001-6633-3447 NR 18 TC 5 Z9 5 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 4 PY 2000 VL 104 IS 17 BP 4011 EP 4016 DI 10.1021/jp994361g PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 311EY UT WOS:000086872800021 ER PT J AU Rustad, JR Dixon, DA Kubicki, JD Felmy, AR AF Rustad, JR Dixon, DA Kubicki, JD Felmy, AR TI Gas-phase acidities of tetrahedral oxyacids from ab initio electronic structure theory SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR STATICS CALCULATIONS; FUEL COMBUSTION RESIDUES; GAUSSIAN-BASIS SETS; PROTON BINDING; INORGANIC CONSTITUENTS; VIBRATIONAL-SPECTRA; GOETHITE SURFACES; 1ST EXAMPLE; ROW ATOMS; ENERGIES AB Density functional calculations have been performed on several protonation states of the oxyacids of Si, P, V, As, Cr, and S. Structures and vibrational frequencies are in good agreement with experimental values where these are available. A reasonably well-defined correlation between the calculated gas-phase acidities and the measured pK(a) in aqueous solution has been found. The pK(a)/gas-phase acidity slopes are consistent with those derived from previous molecular mechanics calculations on ferric hydrolysis and the first two acidity constants for orthosilicic acid. The successive deprotonation of other HnTO4 species, for a given tetrahedral anion T are roughly consistent with this slope, but not to the extent that there is a universal correlation among all species. C1 Pacific NW Natl Lab, Wiley Lab, Richland, WA 99352 USA. Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. RP Rustad, JR (reprint author), Pacific NW Natl Lab, Wiley Lab, Richland, WA 99352 USA. RI Kubicki, James/I-1843-2012 OI Kubicki, James/0000-0002-9277-9044 NR 51 TC 40 Z9 41 U1 3 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 4 PY 2000 VL 104 IS 17 BP 4051 EP 4057 DI 10.1021/jp993421f PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 311EY UT WOS:000086872800026 ER PT J AU Zaban, A Aruna, ST Tirosh, S Gregg, BA Mastai, Y AF Zaban, A Aruna, ST Tirosh, S Gregg, BA Mastai, Y TI The effect of the preparation condition of TiO2 colloids on their surface structures SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID NANOCRYSTALLINE TIO2; SEMICONDUCTOR-FILMS; PHASE-STABILITY; SOLAR-CELLS; DYE; ELECTRODES; ANATASE; PHOTOCURRENT; ADSORPTION; EFFICIENCY AB Hydrothermal synthesis of TiO2 colloids is based on hydrolysis and pressure treatment of titanium isopropoxide precursor in acidic solutions. The influence of the use of nitric and acetic acids during the synthesis was studied, showing a significant effect on the colloid crystal structure. Both dark-field TEM and phase transformation temperature measurements indicate that the colloids prepared in acetic acid contain more of the {101} face compared with the colloids prepared in nitric acid. The surface structure difference affects the performance of dye-sensitized solar cells that consist of electrodes made from these colloids. Better performance is achieved using the colloids prepared in nitric acid, indicating the importance of controlled colloid fabrication for higher conversion efficiencies. C1 Bar Ilan Univ, Dept Chem, IL-52900 Ramat Gan, Israel. Natl Renewable Energy Lab, Golden, CO 80401 USA. Weizmann Inst Sci, Dept Mat & Interfaces, IL-76100 Rehovot, Israel. RP Zaban, A (reprint author), Bar Ilan Univ, Dept Chem, IL-52900 Ramat Gan, Israel. RI Reddy, Aruna/B-6493-2008 NR 30 TC 147 Z9 153 U1 4 U2 45 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAY 4 PY 2000 VL 104 IS 17 BP 4130 EP 4133 DI 10.1021/jp993198m PG 4 WC Chemistry, Physical SC Chemistry GA 311FA UT WOS:000086873000018 ER PT J AU Fan, HY Lu, YF Stump, A Reed, ST Baer, T Schunk, R Perez-Luna, V Lopez, GP Brinker, CJ AF Fan, HY Lu, YF Stump, A Reed, ST Baer, T Schunk, R Perez-Luna, V Lopez, GP Brinker, CJ TI Rapid prototyping of patterned functional nanostructures SO NATURE LA English DT Article ID MESOPOROUS MOLECULAR-SIEVES; SELF-ASSEMBLED MONOLAYERS; SILICA; FILMS; MICROFABRICATION; SURFACE; GOLD AB Living systems exhibit form and function on multiple length scales and at multiple locations. In order to mimic such natural structures, it is necessary to develop efficient strategies for assembling hierarchical materials. Conventional photolithography, although ubiquitous in the fabrication of microelectronics and microelectromechanical systems, is impractical for defining feature sizes below 0.1 micrometres and poorly suited to pattern chemical functionality. Recently, so-called 'soft' lithographic approaches(1) have been combined with surfactant(2,3) and particulate(4) templating procedures to create materials with multiple levels of structural order. But the materials thus formed have been limited primarily to oxides with no specific functionality, and the associated processing times have ranged from hours to days. Here, using a self-assembling 'ink', we combine silica-surfactant self-assembly with three rapid printing procedures-pen lithography, ink-jet printing, and dip-coating of patterned self-assembled monolayers-to form functional, hierarchically organized structures in seconds. The rapid-prototyping procedures we describe are simple, employ readily available equipment, and provide a link between computer-aided design and self-assembled nanostructures. We expect that the ability to form arbitrary functional designs on arbitrary surfaces will be of practical importance for directly writing sensor arrays and fluidic or photonic systems. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ New Mexico, Ctr Microengineered Mat, Albuquerque, NM 87131 USA. Univ New Mexico, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. RP Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. EM cjbrink@sandia.gov NR 32 TC 327 Z9 338 U1 16 U2 129 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD MAY 4 PY 2000 VL 405 IS 6782 BP 56 EP 60 DI 10.1038/35011026 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 311TK UT WOS:000086901600048 ER PT J AU Wallingford, JB Rowning, BA Vogeli, KM Rothbacher, U Fraser, SE Harland, RM AF Wallingford, JB Rowning, BA Vogeli, KM Rothbacher, U Fraser, SE Harland, RM TI Dishevelled controls cell polarity during Xenopus gastrulation SO NATURE LA English DT Article ID SIGNALING PATHWAYS; LAEVIS; ORGANIZER; MOVEMENT; MESODERM; MOTILITY; KINASE; AXIS AB Although cell movements are vital for establishing the normal architecture of embryos, it is unclear how these movements are regulated during development in vertebrates. Inhibition of Xenopus Dishevelled (Xdsh) function disrupts convergent extension movements of cells during gastrulation, but the mechanism of this effect is unclear, as cell fates are not affected(1). In Drosophila, Dishevelled controls both cell fate and cell polarity(2-4), but whether Dishevelled is involved in controlling cell polarity in vertebrate embryos has not been investigated. Here we show, using time-lapse confocal microscopy, that the failure of cells lacking Xdsh function to undergo convergent extension results from defects in cell polarity. Furthermore, Xdsh mutations that inhibit convergent extension correspond to mutations in Drosophila Dishevelled that selectively perturb planar cell polarity. Finally, the localization of Xdsh at the membrane of normal dorsal mesodermal cells is consistent with Xdsh controlling cell polarity. Our results show that polarized cell behaviour is essential for convergent extension and is controlled by vertebrate Dishevelled. Thus, a vertebrate equivalent of the Drosophila planar cell polarity signalling cascade may be required for normal gastrulation. C1 Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Life Sci Div MS6 2100, Berkeley, CA 94720 USA. CALTECH, Div Biol, Pasadena, CA 91125 USA. CALTECH, Beckman Inst, Pasadena, CA 91125 USA. RP Harland, RM (reprint author), Univ Calif Berkeley, Dept Mol & Cell Biol, 401 Barker Hall, Berkeley, CA 94720 USA. NR 17 TC 510 Z9 521 U1 2 U2 18 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 4 PY 2000 VL 405 IS 6782 BP 81 EP 85 DI 10.1038/35011077 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 311TK UT WOS:000086901600055 PM 10811222 ER PT J AU Macchiavelli, AO Fallon, P Clark, RM Cromaz, M Deleplanque, MA Diamond, RM Lane, GJ Lee, IY Stephens, FS Svensson, CE Vetter, K Ward, D AF Macchiavelli, AO Fallon, P Clark, RM Cromaz, M Deleplanque, MA Diamond, RM Lane, GJ Lee, IY Stephens, FS Svensson, CE Vetter, K Ward, D TI Collective T=0 pairing in N = Z nuclei? Pairing vibrations around Ni-56 revisited SO PHYSICS LETTERS B LA English DT Article AB We present a new analysis of the pairing vibrations around Ni-56, With emphasis on odd-odd nuclei. This analysis of the experimental excitation energies is based on the subtraction of average properties that include the full symmetry energy together with the volume, surface, and Coulomb terms. The results clearly indicate a collective behavior of the isovector pairing vibrations and do not support any appreciable collectivity in the isoscalar channel. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RP Macchiavelli, AO (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Nucl Sci, Berkeley, CA 94720 USA. RI Lane, Gregory/A-7570-2011 OI Lane, Gregory/0000-0003-2244-182X NR 14 TC 42 Z9 42 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 MAY 4 PY 2000 VL 480 IS 1-2 BP 1 EP 6 DI 10.1016/S0370-2693(00)00381-6 PG 6 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 315PA UT WOS:000087121100001 ER PT J AU Arkani-Hamed, N Dimopoulos, S Kaloper, N Sundrum, R AF Arkani-Hamed, N Dimopoulos, S Kaloper, N Sundrum, R TI A small cosmological constant from a large extra dimension SO PHYSICS LETTERS B LA English DT Article ID 3-BRANE UNIVERSE; COMPACTIFICATION; MILLIMETER; HIERARCHY AB We propose a new approach to the Cosmological Constant Problem which makes essential use of an extra dimension. A model is presented in which the Standard Model vacuum energy "warps" the higher-dimensional spacetime while preserving 4D flatness. We argue that the strong curvature region of our solutions may effectively cut off the size of the extra dimension, thereby giving rise to macroscopic 4D gravity without a cosmological constant. In our model, the higher-dimensional gravity dynamics is treated classically with carefully chosen couplings. Our treatment of the Standard Model is however fully quantum field-theoretic, and the 4D flatness of our solutions is robust against Standard Model quantum loops and changes to Standard Model couplings. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Dept Phys, Berkeley, CA 94530 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94530 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. RP Arkani-Hamed, N (reprint author), Univ Calif Berkeley, Dept Phys, Berkeley, CA 94530 USA. NR 27 TC 309 Z9 311 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 MAY 4 PY 2000 VL 480 IS 1-2 BP 193 EP 199 DI 10.1016/S0370-2693(00)00359-2 PG 7 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 315PA UT WOS:000087121100030 ER PT J AU Maitra, S Dombrowski, SM Basu, M Raustol, O Waters, LC Ganguly, R AF Maitra, S Dombrowski, SM Basu, M Raustol, O Waters, LC Ganguly, R TI Factors on the third chromosome affect the level of Cyp6a2 and Cyp6a8 expression in Drosophila melanogaster SO GENE LA English DT Article DE chromosome substitution; gene regulation; insecticide resistance; multigene family; RNA analysis ID BARBITAL-INDUCED EXPRESSION; MUSCA-DOMESTICA; MALATHION-RESISTANCE; PAPILIO POLYXENES; HOUSE-FLIES; CYTOCHROME-P450; GENE; P450; INVOLVEMENT; POPULATION AB The expression of two second chromosome-linked cytochrome P450 genes, Cyp6a2 and Cyp6a8, of Drosophila melanogaster was measured in various strains. Six different strains, including ry(506) and 91-C, showed low or undetectable levels of CYP6A2 and CYP6A8 mRNAs, suggesting that low expression is the wild-type phenotype of Cyp6a2 and Cyp6a8 genes. In the 91-R and MHIII-D23 strains, however, both these genes are overexpressed. In order to examine the genetic basis of Cyp6a2 and Cyp6a8 expression, CYP6A2 and CYP6A8 RNA levels were measured in the Fl hybrids of overproducer (91-R and MHIII-D23) and underproducer (rq(506) and 91-C) strains. Results showed that the total amounts of CYP6A2 and CYP6A8 mRNAs in the Fl hybrids were lower than half the amounts of these RNAs found in the overproducer parental strains. This suggested that the underproducer strains carry loci which downregulate Cyp6a2 and Cyp6a8 gene expression. To determine the chromosome linkage of these loci, several stocks homozygous for the second chromosome of overproducer 91-R strain and, therefore, homozygous for the Cyp6a2-91R and Cyp6a8-91R alleles were synthesized. The third chromosomes in all these stocks were from the underproducer ry(506) strain. The levels of expression of both Cyp6a2-91R and Cyp6a8-91R genes in these three stocks were significantly lower than that observed in the 91-R strain. One of these stocks, named iso-2, showing reduced expression, was used to synthesize two new isogenic stocks by resubstituting the third chromosome of ry(506) origin with third chromosomes of the 91-R strain. Expression of both Cyp6a2-91R and Cyp6a8-91R alleles was found to be much higher in these two resubstituted isogenic stocks than in the progenitor iso-2 stock. Taken together, these results suggest that the second chromosome-linked Cyp6a2 and Cypa8 genes are regulated by loci present on the third chromosome, and the wild-type function of these loci is to repress these two Cyp genes. The data also suggest that Cyp6a2 and Cyp6a8 overexpression in the 91-R and MHIII-D23 strains is more likely due to mutation in the repressor locus (or loci) rather than in the cis-regulatory sequences of the Cyp6a-2 and Cypda8 genes. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Ganguly, R (reprint author), Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Knoxville, TN 37996 USA. EM rganguly@utk.edu NR 25 TC 47 Z9 52 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-1119 J9 GENE JI Gene PD MAY 2 PY 2000 VL 248 IS 1-2 BP 147 EP 156 DI 10.1016/S0378-1119(00)00129-3 PG 10 WC Genetics & Heredity SC Genetics & Heredity GA 315JZ UT WOS:000087111700016 PM 10806360 ER PT J AU Wu, K Iedema, MJ Cowin, JP AF Wu, K Iedema, MJ Cowin, JP TI Ion transport in micelle-like films: Soft-landed ion studies SO LANGMUIR LA English DT Article ID WATER-ICE; INTERFACE; DYNAMICS AB Ion-transport processes across epitaxially grown micelle-like films in the form of liquid hydrocarbon/water/hydrocarbon sandwiches were studied by a novel ion soft-landing technique. Centered inside of vapor-deposited glassy films of 3-methylpentane (166 monolayers) and methylcyclohexane (50 monolayers) was a water layer from 0 to 10 monolayers thick. From 90 to 150 K we time-resolved hydronium ion motion and found that the ions (D3O+)clearly paused in the aqueous phase, being transiently trapped by solvation interactions. A modified Born solvation model qualitatively showed that a trap energy gradually built up in the aqueous phase with the water layer thickness. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. RP Cowin, JP (reprint author), Pacific NW Natl Lab, Box 999,MS K8-88, Richland, WA 99352 USA. RI Wu, Kai/A-4903-2011 OI Wu, Kai/0000-0002-5016-0251 NR 27 TC 9 Z9 9 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 2 PY 2000 VL 16 IS 9 BP 4259 EP 4265 DI 10.1021/la990852g PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 311WQ UT WOS:000086909500032 ER PT J AU Hu, JZ Wang, W Bai, S Pugmire, RJ Taylor, CMV Grant, DM AF Hu, JZ Wang, W Bai, S Pugmire, RJ Taylor, CMV Grant, DM TI Investigation of polyethylene by means of magic angle turning and separated-local-field experiments SO MACROMOLECULES LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; CHEMICAL-SHIFT ANISOTROPY; TENSOR PRINCIPAL VALUES; DENSITY POLYETHYLENE; DEUTERON NMR; C-13 NMR; CRYSTALLINE; SOLIDS; PHASE; RELAXATION AB The principal values of the C-13 chemical shift tensors and the H-1-C-13 separated-local-field patterns are reported for the all-trans structures with long and short T-1 as well as the more and less mobile amorphous segments in polyethylene. It is shown that the principal values of the chemical shift tensor, and the local H-1 field of the tensor, for the all-trans crystalline structures with long and short T-1 are essentially the same, supporting the previous suggestion by Schmidt-Rohr and Spiess that chain diffusion between the amorphous and the crystalline regions in PE is the primary reason for the multiexponential C-13 T-1 relaxation observed for the all-trans peak observed at 33 ppm. The less mobile amorphous component adopts preferably a trans conformation and undergoes a fast rotation dominantly about the molecular axis at a rate larger than the width of the CH2 group dipolar coupling. The motion involved in the mobile amorphous structure approaches isotropic tumbling, but a modest amount of constrained reorientation remains. Consequently, the C-13-H-1 dipolar coupling is averaged out, but the shift tensor is not totally averaged to its isotropic value. C1 Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. Univ Utah, Dept Chem & Fuels Engn, Salt Lake City, UT 84112 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Pugmire, RJ (reprint author), Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. RI Hu, Jian Zhi/F-7126-2012 NR 28 TC 12 Z9 12 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 2 PY 2000 VL 33 IS 9 BP 3359 EP 3367 DI 10.1021/ma9916842 PG 9 WC Polymer Science SC Polymer Science GA 311FX UT WOS:000086875000026 ER PT J AU Baker, GA AF Baker, GA TI Defects and the convergence of Pade approximants SO ACTA APPLICANDAE MATHEMATICAE LA English DT Article; Proceedings Paper CT International Conference on Rational Approximation (ICRA99) CY JUN 06-11, 1999 CL ANTWERP, BELGIUM SP Fonds Wetebschapplijk Onderzoek Vlaanderen, Univ Antwerpen, Wetenschappelijke Onderzoeksgemeenschap FWO V DE rational approximation; Pade approximants; convergence properties ID POLYNOMIALS AB A selective survey is given of convergence results for sequences of Pade approximants. Various approaches for dealing with the convergence problems due to `defects' are discussed. Attention is drawn to the close relationship between analyticity properties of a function and the `smoothness' of its Taylor series coefficients. A new theorem on the convergence of horizontal sequences of Pade approximants to functions in the Baker-Gammel-Wills conjecture function class is presented. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Baker, GA (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 39 TC 8 Z9 9 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-8019 J9 ACTA APPL MATH JI Acta Appl. Math. PD MAY PY 2000 VL 61 IS 1-3 BP 37 EP 52 PG 16 WC Mathematics, Applied SC Mathematics GA 341GV UT WOS:000088583400005 ER PT J AU Lowndes, DH AF Lowndes, DH TI Nanotechnology overview SO ADVANCED MATERIALS & PROCESSES LA English DT Article AB Nanotechnology is the study and use of materials, devices, and systems on the scale of a nanometer If researchers can learn to manipulate individual atoms at this scale, some experts believe the results could lead to a revolution in computing, electronics, energy, materials design, manufacturing, medicine, and numerous other fields. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Lowndes, DH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. NR 0 TC 4 Z9 5 U1 0 U2 1 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0882-7958 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD MAY PY 2000 VL 157 IS 5 BP 48 EP 51 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 312TA UT WOS:000086958000006 ER PT J AU Hollowood, TJ Khoze, VV Mattis, MP AF Hollowood, Timothy J. Khoze, Valentin V. Mattis, Michael P. TI Instantons in N=4 Sp(N) and SO(N) theories and the AdS/CFT correspondence SO ADVANCES IN THEORETICAL AND MATHEMATICAL PHYSICS LA English DT Article DE Solitons Monopoles and Instantons; 1/N Expansion; Duality in Gauge Field Theories; Supersymmetry and Duality AB Following work on theories with SU(N) gauge groups, we perform a large-N saddle-point approximation of the measure for ADHM multi-instantons in N = 4 supersymmetric gauge theories with symplectic or orthogonal gauge groups. For Sp(N) we find that a saddle-point only exists in the even instanton charge sector. For either Sp(N) or SO(N) the saddle-point solution parametrizes AdS(5) x RP5, the dual supergravity geometry in the AdS/CFT correspondence for these theories. The instanton measure at large-N has the form of the partition function of ten-dimensional N = 1 supersymmetric gauge theory with a unitary gauge group dimensionally reduced to zero dimensions. C1 [Hollowood, Timothy J.; Mattis, Michael P.] Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. [Khoze, Valentin V.] Univ Durham, Dept Phys, Durham DH1 3LE, England. [Hollowood, Timothy J.] Univ Coll Swansea, Dept Phys, Swansea SA2 8PP, W Glam, Wales. RP Hollowood, TJ (reprint author), Los Alamos Natl Lab, Div Theoret, T-8, Los Alamos, NM 87545 USA. EM pyth@skye.lanl.gov; valya.khoze@durham.ac.uk; mattis@lanl.gov FU TMR network [FMRX-CT96-0012] FX We acknowledge Matt Strassler for first pointing out to us the generalization of the AdS/CFT correspondence to the other classical groups. VVK and MPM acknowledge a NATO Collaborative Research Grant, TJH and VVK acknowledge the TMR network grant FMRX-CT96-0012. NR 25 TC 3 Z9 3 U1 0 U2 0 PU INT PRESS BOSTON, INC PI SOMERVILLE PA PO BOX 43502, SOMERVILLE, MA 02143 USA SN 1095-0761 J9 ADV THEOR MATH PHYS JI Adv. Theor. Math. Phys. PD MAY PY 2000 VL 4 IS 3 PG 19 WC Physics, Particles & Fields; Physics, Mathematical SC Physics GA V22QI UT WOS:000208289300002 ER PT J AU Alvin, KF AF Alvin, KF TI Method for treating discretization error in nondeterministic analysis SO AIAA JOURNAL LA English DT Article ID VALIDATION; SPACE AB A response surface methodology-based technique is presented for treating discretization error in nondeterministic analysis. The response surface, or metamodel, is estimated from computer experiments that vary both uncertain physical parameters and the fidelity of the computational mesh. The resultant metamodel is then used to propagate the variabilities in the continuous input parameters, while the mesh size is taken to zero, its asymptotic limit. With respect to mesh size, the metamodel is equivalent to Richardson extrapolation, in which solutions on coarser and finer meshes are used to estimate discretization error, The method is demonstrated on a one-dimensional prismatic bar, in which uncertainty in the third vibration frequency is estimated by propagating variations in material modulus, density, and bar length. The results demonstrate the efficiency of the method fur combining nondeterministic analysis with error estimation to obtain estimates of total simulation uncertainty The results also show the relative sensitivity of failure estimates to solution bias errors in a reliability analysis, particularly when the physical variability of the system is low. C1 Sandia Natl Labs, Struct Dynam & Vibrat Control Dept, Albuquerque, NM 87185 USA. RP Alvin, KF (reprint author), Sandia Natl Labs, Struct Dynam & Vibrat Control Dept, POB 5800,Mail Stop 0439, Albuquerque, NM 87185 USA. NR 18 TC 1 Z9 1 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAY PY 2000 VL 38 IS 5 BP 910 EP 916 PG 7 WC Engineering, Aerospace SC Engineering GA 311UD UT WOS:000086903300020 ER PT J AU Jacobsen, SD Smyth, JR Swope, RJ Sheldon, RI AF Jacobsen, SD Smyth, JR Swope, RJ Sheldon, RI TI Two proton positions in the very strong hydrogen bond of serandite, NaMn2[Si3O8(OH)] SO AMERICAN MINERALOGIST LA English DT Article ID MINERALS; SILICATES AB The crystal structure and hydrogen positions of serandite, NaMn2[Si3O8(OH)], have been refined from single-crystal X-ray and time-of-flight neutron diffraction data at ambient conditions. The proton occupies an asymmetric, double-well position between O3 and O4, confirming one of the shortest asymmetric hydrogen bonds known in minerals with n(O3...O4) = 2.464(1) Angstrom (X-ray) and 2.467(1) Angstrom (neutron). The proton position closest to O3 has about 84% occupancy and an O-H distance of 1.078(3) Angstrom, and the position closest to O4 has an occupancy of 16% and an O-H distance of 1.07(1) Angstrom. The d(H...O) of these hydrogen bonds is 1.413(3) Angstrom and 1.41(1) Angstrom, respectively. Hydrogen bond angles are 164 degrees for H1 and 168 degrees for H2. The Si-IV-OH bond length [1.628(1) Angstrom] is intermediate in length among the three other Si-O bonds in the dominantly (84%) hydrated Si1 tetrahedron. These new structure data for a very strong hydrogen bond may be useful for extending spectroscopy-structure correlation diagrams into the region of very low energy O-H stretching. C1 Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Jacobsen, SD (reprint author), Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. RI Jacobsen, Steven/F-3443-2013 OI Jacobsen, Steven/0000-0002-9746-958X NR 30 TC 25 Z9 26 U1 0 U2 2 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 2000 VL 85 IS 5-6 BP 745 EP 752 PG 8 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 313GV UT WOS:000086992700011 ER PT J AU Headrick, J Sepaniak, M Alexandratos, S Datskos, P AF Headrick, J Sepaniak, M Alexandratos, S Datskos, P TI Chelating scintillation fibers for measurements of Cs-137 SO ANALYTICAL CHEMISTRY LA English DT Article ID ION-EXCHANGE AB Solid scintillating fibers, coated with a dual-mechanism bifunctional polymer shown to bind Cs(I) in alkaline solutions, were developed for measurement of Cs-137. The effect of the epoxy-polymer coating thickness on attenuation of the signal from Cs-137 was evaluated. After optimal coating conditions were determined, both scintillation fiber and resin functions were retained, producing stable field-ready fibers. Temporal studies were performed to examine:the kinetics of Cs-137 uptake into the resin. Calibration curves of the fiber response were generated by beta-emission from solutions of Cs-137 dissolved in 1 M sodium hydroxide. The plots exhibited a linear response over a range of 4-3200 nCi/mL (3.4 x 10(-10)-2.7 x 10(-7) M Cs-137), with a limit of detection of 3.65 nCi/mL (similar to 42 parts per trillion Cs-137). The distribution coeffcient of Cs was determined to be 490 +/- 50 mL/g from these measurements. Selectivity studies of the resin were performed in the presence of 100 fold excess of Sr(II), Al(III), and nonradioactive Cs(I), Linear calibration plots were obtained in the presence of these potential interferences, but at a reduced sensitivity. The fibers were also used to evaluate the Cs-137 content of a mock tank waste sample to show the potential of the fibers in complicated matrixes. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Engn Technol Div, Oak Ridge, TN 37831 USA. RP Sepaniak, M (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NR 19 TC 12 Z9 12 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 2000 VL 72 IS 9 BP 1994 EP 2000 DI 10.1021/ac9910536 PG 7 WC Chemistry, Analytical SC Chemistry GA 312DE UT WOS:000086927300017 ER PT J AU Wang, ZQ Haydon, PG Yeung, ES AF Wang, ZQ Haydon, PG Yeung, ES TI Direct observation of calcium-independent intercellular ATP signaling in astrocytes SO ANALYTICAL CHEMISTRY LA English DT Article ID CULTURED HIPPOCAMPAL-NEURONS; INOSITOL 1,4,5-TRISPHOSPHATE; BIOLUMINESCENCE ASSAY; CA2+ OSCILLATIONS; CELLS; WAVES; RELEASE; RAT; TRISPHOSPHATE; MOBILIZATION AB Adenosine triphosphate (ATP) is assumed to be involved in the regulation of many extracellular signaling systems including calcium wave propagation. So far all supportive evidence is indirect, such as monitoring changes in intracellular calcium on application of extracellular ATP or off-site measurement of ATP from superfusates. Furthermore, the causal relationships among the various signaling agents are still unclear. A novel chemiluminescence dynamic imaging method was developed to monitor ATP release from living biological cells. The assay has linear response over 3 orders of magnitude for fixed concentrations of enzyme and cofactors, with a correlation coefficient of 0.999. The detectability of ATP is down to 10(-8) M at millisecond exposure times with an intensified charge-coupled device camera. The direct imaging of ATP waves in astrocyte cultures was performed together with Fluo-3-Ca imaging at millisecond temporal resolution and micrometer-scale spatial resolution. We discovered that extracellular ATP mediates intercellular calcium wave propagation, but surprisingly, release and propagation of ATP are not calcium dependent. Therefore, ATP rather than Ca or IP3 is the primary intercellular signaling messenger. C1 Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Iowa State Univ, Dept Zool & Genet, Neurosci Program, Ames, IA 50011 USA. RP Yeung, ES (reprint author), Iowa State Univ, US DOE, Ames Lab, Ames, IA 50011 USA. NR 62 TC 148 Z9 155 U1 1 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 2000 VL 72 IS 9 BP 2001 EP 2007 DI 10.1021/ac9912146 PG 7 WC Chemistry, Analytical SC Chemistry GA 312DE UT WOS:000086927300018 PM 10815957 ER PT J AU Pretty, JR Deng, HT Goeringer, DE Van Berkel, GJ AF Pretty, JR Deng, HT Goeringer, DE Van Berkel, GJ TI Electrochemically modulated preconcentration and matrix elimination for organic analytes coupled on-line with electrospray mass spectrometry SO ANALYTICAL CHEMISTRY LA English DT Article ID ANODIC-STRIPPING VOLTAMMETRY; ATOMIC-EMISSION-SPECTROMETRY; PRE-CONCENTRATION TECHNIQUE; FLOW CELL; SIGNAL ENHANCEMENT; ICP-MS; ONLINE; PRETREATMENT; URANIUM; TAMOXIFEN AB Demonstrated for the first time is the use of electrochemically modulated preconcentration and sample matrix elimination combined on-line with electrospray mass spectrometry (EMPM/ES-MS) for the enhanced analysis of organics by ES-MS. EMPM is similar to adsorptive stripping analysis. Accumulation of the targeted analytes at the working electrode of an on-line electrochemical now cell is accomplished via a nonelectrolytic adsorption process that is controlled through the proper combination of the soh ent system, the working electrode material, and applied potential. Once on the electrode, the analyte may be washed free of sample mab;ix components detrimental to mass spectrometric detection. The potential applied to the electrode during the detection step is chosen to release Or strip the analytes unaltered back into the solvent stream for mass spectrometric detection rather than to oxidize or reduce them as would be the case for electrochemical detection. Thus, retention and elution of a target analyte with EMPM are controlled by switching the working electrode potential, rather than via a switch in mobile-phase composition, as is done in more traditional preconcentration and cleanup schemes used on-line with ES-MS. The proof-of-principle studies described here use the breast cancer drug tamoxifen and a metabolite, 4-hydroxytamoxifen, as the target analytes. A thin-layer, flow-by electrode cell with a glassy carbon working electrode is used as the preconcentration device. The nature of the working electrode, the solvent systems, and the electrode potentials necessary to accumulate and strip tamoxifen and 4-hydroxytamoxifen are discussed. Calibration curves were fitted using the Langmuir isotherm, Detection limits (DLs) using a 5.0 min preconcentration period with selected reaction monitoring for tamoxifen (m/z 372 --> 72) were bracketed as 0.010 nM < DL < 0.025 nM. The ability to simultaneously detect low nanomolar levels of both tamoxifen and 4-hydroxytamoxifen hi pristine solution and 1/10 diluted urine is also demonstrated. C1 Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Van Berkel, GJ (reprint author), Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. FU NCI NIH HHS [Y1-CB-0016-01] NR 29 TC 22 Z9 22 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 2000 VL 72 IS 9 BP 2066 EP 2074 DI 10.1021/ac990813+ PG 9 WC Chemistry, Analytical SC Chemistry GA 312DE UT WOS:000086927300028 PM 10815967 ER PT J AU Lazar, AC Reilly, PTA Whitten, WB Ramsey, JM AF Lazar, AC Reilly, PTA Whitten, WB Ramsey, JM TI Laser desorption/in situ chemical ionization aerosol mass spectrometry for monitoring tributyl phosphate on the surface of environmental particles SO ANALYTICAL CHEMISTRY LA English DT Article ID MOLECULES; IONS AB The possibility of using real-time aerosol mass spectrometry (RTAMS) for the detection of surface-adsorbed tributyl phosphate (TBP) as an alkali metal adduct has been investigated. Environmental particles contain variable amounts of easily ionizable alkali metals. During laser desorption of surface-adsorbed TBP molecules, Na+ and K+ ions are generated by the interaction of the laser radiation with the particle's material. The alkali metal ions serve as in situ chemical ionization reagents of the neutral analyte molecules. The effect of laser fluence on the signal intensities of the potassium ion and cationized TBP was also studied. The best performance of the instrument was observed with laser fluences that produce high abundances of K+ but low abundances of ions from the particle's bulk material. The relatively low laser fluence, necessary to produce potassium ions, prevents the excessive fragmentation of the analyte. The instrument is capable of real-time monitoring of submonolayer coverage of TBP on the surface of micron-sized particles. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Whitten, WB (reprint author), Oak Ridge Natl Lab, POB 2008, Oak Ridge, TN 37831 USA. NR 25 TC 14 Z9 14 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 2000 VL 72 IS 9 BP 2142 EP 2147 DI 10.1021/ac991393r PG 6 WC Chemistry, Analytical SC Chemistry GA 312DE UT WOS:000086927300038 PM 10815977 ER PT J AU Shen, YF Berger, SJ Anderson, GA Smith, RD AF Shen, YF Berger, SJ Anderson, GA Smith, RD TI High-efficiency capillary isoelectric focusing of peptides SO ANALYTICAL CHEMISTRY LA English DT Article ID ZONE-ELECTROPHORESIS; MASS-SPECTROMETRY; LIQUID-CHROMATOGRAPHY; PROTEINS; SEPARATIONS; PERFORMANCE; RESOLUTION; COATINGS; COLUMNS AB Several approaches are presently being developed for global proteome characterization that are based upon the analysis of polypeptide mixtures resulting from digestion of (often complex) mixtures of proteins. Improved methods for,peptide analysis are needed that provide for sample concentration, higher resolution separations, and direct compatibility with mass spectrometry. In this work, methods for the high-efficiency capillary isoelectric focusing (CIEF) separation of peptides have been developed that provide for simultaneous sample concentration and separation according to peptide isoelectric point. Under typical nondenaturing CIEF conditions, peptides are concentrated similar to 500-fold, and peptides present at <1 ng/ mu L were detectable using conventonal UV detection. CIEF separations of peptides provided much faster measurements of isoelectric points compared with conventional isoelectric focusing in gels. Very small differences in peptide isoelectric points (Delta pI similar to 0.01) could be resolved. High-efficiency CIEF separations for complex peptide mixtures from tryptic digestion of yeast cytosol fractions were obtained and showed significant improvement over those obtained using capillary zone electrophoresis and packed capillary reversed-phase liquid chromatography. C1 Pacific NW Natl Lab, Environm Mol Sci Lab, Richland, WA 99352 USA. RP Smith, RD (reprint author), Pacific NW Natl Lab, Environm Mol Sci Lab, POB 999, Richland, WA 99352 USA. RI Smith, Richard/J-3664-2012 OI Smith, Richard/0000-0002-2381-2349 FU NCI NIH HHS [CA81654] NR 29 TC 87 Z9 92 U1 1 U2 16 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 2000 VL 72 IS 9 BP 2154 EP 2159 DI 10.1021/ac991367t PG 6 WC Chemistry, Analytical SC Chemistry GA 312DE UT WOS:000086927300040 PM 10815979 ER PT J AU Fredrickson, JK Kostandarithes, HM Li, SW Plymale, AE Daly, MJ AF Fredrickson, JK Kostandarithes, HM Li, SW Plymale, AE Daly, MJ TI Reduction of Fe(III), Cr(VI), U(VI), and Tc(VII) by Deinococcus radiodurans R1 SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SHEWANELLA-PUTREFACIENS MR-1; C-TYPE CYTOCHROME; DISSIMILATORY REDUCTION; RADIATION-RESISTANT; MICROBIAL REDUCTION; ELECTRON-ACCEPTORS; HUMIC SUBSTANCES; IONIZING-RADIATION; METAL REDUCTION; OUTER-MEMBRANE AB Deinococcus radiodurans is an exceptionally radiation-resistant microorganism capable of surviving acute exposures to ionizing radiation doses of 15,000 Gy and previously described as having a strictly aerobic respiratory metabolism. Under strict anaerobic conditions, D. radiodurans R1 reduced Fe(III)-nitrilotriacetic acid coupled to the oxidation of lactate to CO2 and acetate but was unable to link this process to growth. D. radiodurans reduced the humic acid analog anthraquinone-2,6-disulfonate (AQDS) to its dihydroquinone form, AH(2)DS. which subsequently transferred electrons to the Fe(III) oxides hydrous ferric oxide and goethite via a previously described electron shuttle mechanism. D. radiodurans reduced the solid phase Fe(III) oxides in the presence of either 0.1 mM AQDS or leonardite humic acids (2 mg ml(-1)) but not in their absence. D, radiodurans also reduced U(VI) and Tc(VII) in the presence of AQDS. In contrast, Cr(VI) was directly reduced in anaerobic cultures with lactate although the rate of reduction was higher in the presence of AQDS. The results are the first evidence that D. radiodurans can reduce Fe(III) coupled to the oxidation of lactate or other organic compounds. Also, D. radiodurans, in combination with humic acids or synthetic electron shuttle agents, can reduce U and Te and thus has potential applications for remediation of metal- and radionuclide-contaminated sites where ionizing radiation or other DNA-damaging agents may restrict the activity of more sensitive organisms. C1 Pacific NW Lab, Richland, WA 99352 USA. Uniformed Serv Univ Hlth Sci, Bethesda, MD 20814 USA. RP Fredrickson, JK (reprint author), Pacific NW Lab, MSIN P7-50,POB 999, Richland, WA 99352 USA. NR 41 TC 193 Z9 220 U1 9 U2 51 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD MAY PY 2000 VL 66 IS 5 BP 2006 EP 2011 DI 10.1128/AEM.66.5.2006-2011.2000 PG 6 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 310BC UT WOS:000086805500037 PM 10788374 ER PT J AU Braker, G Zhou, JZ Wu, LY Devol, AH Tiedje, JM AF Braker, G Zhou, JZ Wu, LY Devol, AH Tiedje, JM TI Nitrite reductase genes (nirK and nirS) as functional markers to investigate diversity of denitrifying bacteria in Pacific northwest marine sediment communities SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID CONTINENTAL-SHELF SEDIMENTS; NOSZ GENES; SEQUENCES; PRIMERS; DNA AB Genetic heterogeneity of denitrifying bacteria in sediment samples from Puget Sound and two sites on the Washington continental margin was studied by PCR approaches amplifying nirK and nirS genes. These structurally different but functionally equivalent single copy genes coding for nitrite reductases, a key enzyme of the denitrification process, were used as a molecular marker for denitrifying bacteria, nirS sequences could be amplified from samples of both sampling sites, whereas nirK sequences were detected only in samples from the Washington margin. To assess the underlying nir gene structure, PCR products of both genes were cloned and screened by restriction fragment length polymorphism (RFLP). Rarefraction analysis revealed a high level of diversity especially for nirS clones from Puget Sound and a slightly lower level of diversity for nirK and nirS clones from the Washington margin. One group dominated within nirK clones, but no dominance and only a few redundant clones were seen between sediment samples for nirS clones in both habitats. Hybridization and sequencing confirmed that all but one of the 228 putative nirS clones were nirS with levels of nucleotide identities as low as 45.3%. Phylogenetic analysis grouped nirS clones into three distinct subclusters within the nirS gene tree which corresponded to the two habitats from which they were obtained. These sequences had little relationship to any strain with known nirS sequences or to isolates (mostly close relatives of Pseudomonas stutzeri) from the Washington margin sediment samples. nirK clones were more closely related to each other than were the nirS clones, with 78.6% and higher nucleotide identities; clones showing only weak hybridization signals were not related to known nirK sequences. All nirK clones were also grouped into a distinct cluster which could not be placed with any strain with known nirK sequences. These findings show a very high diversity of nir sequences within small samples and that these novel nir clusters, some very divergent from known sequences, are not known in cultivated denitrifiers. C1 Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Washington, Sch Oceanog, Seattle, WA 98295 USA. RP Tiedje, JM (reprint author), Michigan State Univ, Ctr Microbial Ecol, Plant & Soil Sci Bldg, E Lansing, MI 48824 USA. EM tiedjej@pilot.msu.edu RI Braker, Gesche/C-4890-2008; Ducey, Thomas/A-6493-2011 NR 31 TC 266 Z9 304 U1 13 U2 135 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD MAY PY 2000 VL 66 IS 5 BP 2096 EP 2104 DI 10.1128/AEM.66.5.2096-2104.2000 PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 310BC UT WOS:000086805500050 PM 10788387 ER PT J AU Fife, DJ Bruhn, DF Miller, KS Stoner, DL AF Fife, DJ Bruhn, DF Miller, KS Stoner, DL TI Evaluation of a fluorescent lectin-based staining technique for some acidophilic mining bacteria SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SULFUR-OXIDIZING BACTERIA; HETEROTROPHIC BACTERIA; SP-NOV; MICROBIAL-POPULATIONS; MINE DRAINAGE; IRON; SULFOLOBUS; GROWTH; PYRITE; FERROOXIDANS AB A fluorescence-labeled wheat germ agglutinin staining technique (R. K. Sizemore et al., Appl. Environ. Microbiol. 56:2245-2247, 1990) was modified and found to be effective for staining gram-positive, acidophilic mining bacteria. Bacteria identified by others as being gram positive through 16S rRNA sequence analyses, yet clustering near the divergence of that group, stained weakly. Gram-negative bacteria did not stain. Background staining of environmental samples was negligible, and pyrite and soil particles in the samples did not interfere with the staining procedure. C1 Idaho Natl Lab, Idaho Falls, ID 83415 USA. RP Stoner, DL (reprint author), Idaho Natl Lab, POB 1625,MS 2203,2351 North Blvd, Idaho Falls, ID 83415 USA. EM dstoner@inel.gov NR 33 TC 12 Z9 12 U1 0 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD MAY PY 2000 VL 66 IS 5 BP 2208 EP 2210 DI 10.1128/AEM.66.5.2208-2210.2000 PG 3 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 310BC UT WOS:000086805500064 PM 10788401 ER PT J AU Knauss, KG Dibley, MJ Leif, RN Mew, DA Aines, RD AF Knauss, KG Dibley, MJ Leif, RN Mew, DA Aines, RD TI The aqueous solubility of trichloroethene (TCE) and tetrachloroethene (PCE) as a function of temperature SO APPLIED GEOCHEMISTRY LA English DT Article ID HENRYS LAW CONSTANTS; WATER; COEFFICIENTS; REMEDIATION; CHEMICALS; LIQUID AB Using a flexible Au bag autoclave and a precision high-pressure liquid chromatography pump to control pressure, the liquid-liquid aqueous solubilities of TCE and PCE were measured as a Function of temperature from 294 to 434 K (at constant pressure). The results were used to calculate the partial molal thermodynamic quantities of the organic liquid aqueous dissolution reactions: Delta (G) over bar(soln), Delta (H) over bar(soln) and Delta (C) over bar (soln). Calculated values for these quantities at 298 K for TCE are: Delta (G) over bar(soln) = 11.282 (+/-0.003) kJ/mol, Delta (H) over bar(soln) = -3.35 (+/-0.07) kJ/mol, Delta (S) over bar = -49.07 (+/-0.24) J/mol K, and Delta (C) over bar(soln) = 385.2 (+/-3.4) J/mol K. Calculated values for these quantities at 298 K for PCE are: Delta (G) over bar(soln) =15.80 (+/-0.04) kJ/mol, Delta (H) over bar(soln) = -1.79 (+/-0.58) kJ/mol, Delta (S) over bar(soln) = -59.00 (+/-1.96) J/mol K and Delta (C) over bar(p soln) = 354.6 (+/-8.6) J/mol K. These thermodynamic quantities may be used to calculate the solubility of TCE and PCE at any temperature of interest. In the absence of direct measurements over this temperature range, the Henry's Law constants for TCE and PCE have been estimated using the measured aqueous solubilities and calculated vapor pressures. (C) 2000 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RP Knauss, KG (reprint author), Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. RI knauss, kevin/K-2827-2012; Aines, Roger/A-2013-2013 NR 27 TC 23 Z9 23 U1 3 U2 23 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0883-2927 J9 APPL GEOCHEM JI Appl. Geochem. PD MAY PY 2000 VL 15 IS 4 BP 501 EP 512 DI 10.1016/S0883-2927(99)00058-X PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 276CA UT WOS:000084857000008 ER PT J AU Taylor, MA Wingate, BA AF Taylor, MA Wingate, BA TI A generalized diagonal mass matrix spectral element method for non-quadrilateral elements SO APPLIED NUMERICAL MATHEMATICS LA English DT Article; Proceedings Paper CT 4th International Conference on Spectral and High Order Methods (ICOSAHOM 98) CY JUN, 1998 CL HERZLIYYA, ISRAEL SP Tel Aviv Univ, Rectors Off, Tel Aviv Univ, Sch Math Sci, Tel Aviv Univ, Sackler Fdn Computat Math DE triangle; lebesgue constant; spectral elements; h-p finite elements; Fekete points ID POLYNOMIAL INTERPOLATION; POINTS AB We introduce a Fekete point spectral element method. This is a generalization of the traditional quadrilateral based spectral element method to any general element such as triangles. It retains the exponential convergence and the diagonal mass matrix of the original method. We first solve a Sturm-Liouville problem in the square and the triangle to determine the correct functional space used for approximation. Once the functional space is known, we use the Fekete criterion to compute near optimal grids for these spaces which have the same number of points as the dimension of the functional space. This allows the construction of a well-behaved cardinal function basis which leads to a diagonal mass matrix. (C) 2000 IMACS. Published by Elsevier Science B.V. All rights reserved. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM USA. RP Taylor, MA (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. NR 12 TC 36 Z9 37 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9274 J9 APPL NUMER MATH JI Appl. Numer. Math. PD MAY PY 2000 VL 33 IS 1-4 BP 259 EP 265 DI 10.1016/S0168-9274(99)00091-4 PG 7 WC Mathematics, Applied SC Mathematics GA 304EL UT WOS:000086469900026 ER PT J AU Istratov, AA Hieslmair, H Weber, ER AF Istratov, AA Hieslmair, H Weber, ER TI Iron contamination in silicon technology SO APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING LA English DT Review ID X-RAY-FLUORESCENCE; CZOCHRALSKI-GROWN SILICON; MINORITY-CARRIER LIFETIME; ION BACKSCATTERING SPECTROMETRY; SURFACE-RECOMBINATION VELOCITY; NEUTRON-ACTIVATION ANALYSIS; FLOAT-ZONE SILICON; LEVEL TRANSIENT SPECTROSCOPY; BORON-DOPED SILICON; ON-INSULATOR STRUCTURES AB This article continues the review of fundamental physical properties of iron and its complexes in silicon (Appl. Phys. A 69, 13 (1999)), and is focused on ongoing applied research of iron in silicon technology. The first section of this article presents an analysis of the effect of iron on devices, including integrated circuits, power devices, and solar cells. Then, sources of unintentional iron contamination and reaction paths of iron during device manufacturing are discussed. Experimental techniques to measure trace contamination levels of iron in silicon, such as minority carrier lifetime techniques (SPV, mu-PCD. and ELYMAT), deep-level transient spectroscopy (DLTS), total X-ray fluorescence (TXRF) and vapor-phase decomposition TXRF (VPD-TXRF), atomic absorption spectroscopy (AAS), mass spectrometry and its modifications (SIMS, SNMS, ICP-MS), and neutron activation analysis (NAA) rue reviewed in the second section of the article. Prospective analytical tools, such as heavy-ion backscattering spectroscopy (HIBS) and synchrotron-based X-ray microprobe techniques (XPS, XANES, XRF) are briefly discussed. The third section includes a discussion of the present achievements and challenges of the electrochemistry and physics of cleaning of silicon wafers, with an emphasis on removal of iron contamination from the wafers. Finally, the techniques for gettering of iron are presented. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. RP Istratov, AA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, 1 Cyclotron Rd,Mail Stop 62-203, Berkeley, CA 94720 USA. EM istratov@socrates.berkeley.edu; weber@socrates.berkeley.edu OI Hieslmair, Henry/0000-0002-5842-1882 NR 840 TC 214 Z9 232 U1 11 U2 73 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0947-8396 J9 APPL PHYS A-MATER JI Appl. Phys. A-Mater. Sci. Process. PD MAY PY 2000 VL 70 IS 5 BP 489 EP 534 DI 10.1007/s003390051074 PG 46 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 339CQ UT WOS:000088460400001 ER PT J AU Snyder, HR Currier, RP Murillo, MS AF Snyder, HR Currier, RP Murillo, MS TI Plasma fluidized bed imaging and possible strong coupling effects SO APPLIED PHYSICS LETTERS LA English DT Article ID DUSTY PLASMAS; PARTICLES; CRYSTAL; REACTOR; DEPOSITION; LIQUIDS; FLOW AB A plasma fluidized bed was constructed to study the physics of fluidized plasmas. The plasma fluidized bed is a unique system involving contact of hydrodynamically suspended micron-sized (and larger) particles with the current-carrying portion of a plasma. These particles become negatively charged and, under certain conditions, could possibly form a strongly coupled fluidized plasma. Using laser light scattering measurements, we have imaged particles and calculated a coupling parameter showing what could be strongly coupled effects superimposed on the hydrodynamic behavior of the fluidized bed systems. This system may provide an ideal means to experimentally explore the properties and dynamics of strongly coupled plasmas subjected to hydrodynamic shear forces. (C) 2000 American Institute of Physics. [S0003-6951(00)05018-X]. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Snyder, HR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 27 TC 8 Z9 8 U1 1 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 1 PY 2000 VL 76 IS 18 BP 2511 EP 2513 DI 10.1063/1.126392 PG 3 WC Physics, Applied SC Physics GA 307PY UT WOS:000086662900009 ER PT J AU Kostecki, R McLarnon, F AF Kostecki, R McLarnon, F TI Nanometer-scale electrochemical lithography on the spinel oxide LiMn2O4 SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING TUNNELING MICROSCOPE; ATOMIC-FORCE MICROSCOPE; SILICON 100 SURFACES; AIR; FEATURES AB A scheme for nanometer-scale patterning of the surface of a conducting lithium manganese oxide (LiMn2O4) by scanning probe microscopy is described. A significant feature of this work is the demonstration that a localized surface chemical change can be confined to a depth which depends on the oxide-tip voltage bias and ambient humidity. Processing strategies exploiting this localized pattern generation vary from shallow surface property modification to localized etching of the oxide and the formation of nanometer-size pits, wells, or trenches. Unlike the scanning probe based surface oxidation of metals and semiconductors, the electroactive material is altered via electrochemically generated species. (C) 2000 American Institute of Physics. [S0003-6951(00)01818-0]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. RP Kostecki, R (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, 1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 16 TC 13 Z9 13 U1 2 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 1 PY 2000 VL 76 IS 18 BP 2535 EP 2537 DI 10.1063/1.126400 PG 3 WC Physics, Applied SC Physics GA 307PY UT WOS:000086662900017 ER PT J AU Ishimaru, M Afanasyev-Charkin, IV Sickafus, KE AF Ishimaru, M Afanasyev-Charkin, IV Sickafus, KE TI Ion-beam-induced spinel-to-rocksalt structural phase transformation in MgAl2O4 SO APPLIED PHYSICS LETTERS LA English DT Article ID AMORPHIZATION AB An ion-beam-induced metastable phase in magnesium aluminate spinel (MgAl2O4) has been examined in detail using transmission electron microscopy. Single crystals of MgAl2O4 with (111) orientation were irradiated with 180-keV Ne+ ions at 120 K to fluences of 10(16) and 10(17)/cm(2). Selected-area electron diffraction patterns obtained from the irradiation-induced damaged layer revealed that all even hkl reflections (e.g., 222) possess strong intensity, while all odd hkl reflections (e.g., 111) are weak. The features of these diffraction patterns corresponded to those of the rocksalt (NaCl) structure, suggesting that an ordered spinel to disordered rocksalt structural phase transformation in MgAl2O4 was induced by ion beam irradiation. (C) 2000 American Institute of Physics. [S0003-6951(00)00317-X]. C1 Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. RP Ishimaru, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, POB 1663, Los Alamos, NM 87545 USA. NR 12 TC 43 Z9 43 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 1 PY 2000 VL 76 IS 18 BP 2556 EP 2558 DI 10.1063/1.126406 PG 3 WC Physics, Applied SC Physics GA 307PY UT WOS:000086662900024 ER PT J AU Bulaevskii, LN Chudnovsky, EM Maley, MP AF Bulaevskii, LN Chudnovsky, EM Maley, MP TI Magnetic pinning in superconductor-ferromagnet multilayers SO APPLIED PHYSICS LETTERS LA English DT Article ID BOSON LOCALIZATION; PHASE-DIAGRAM; ARRAYS; FILMS; CRYSTALS; DEFECTS; DOTS AB We argue that superconductor/ferromagnet multilayers of nanoscale period should exhibit strong pinning of vortices by the magnetic domain structure in magnetic fields below the coercive field when ferromagnetic layers exhibit strong perpendicular magnetic anisotropy. The estimated maximum magnetic pinning energy for single vortex in such a system is about 100 times larger than the pinning energy by columnar defects. This pinning energy may provide critical currents as high as 10(6)-10(7) A/cm(2) at high temperatures (but not very close to T-c) at least in magnetic fields below 0.1 T. (C) 2000 American Institute of Physics. [S0003-6951(00)02618-8]. C1 CUNY Herbert H Lehman Coll, Dept Phys & Astron, Bronx, NY 10468 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Bulaevskii, LN (reprint author), CUNY Herbert H Lehman Coll, Dept Phys & Astron, 250 Bedford Pk Blvd W, Bronx, NY 10468 USA. NR 21 TC 132 Z9 132 U1 0 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 1 PY 2000 VL 76 IS 18 BP 2594 EP 2596 DI 10.1063/1.126419 PG 3 WC Physics, Applied SC Physics GA 307PY UT WOS:000086662900037 ER PT J AU Freeland, JW Bussmann, K Idzerda, YU AF Freeland, JW Bussmann, K Idzerda, YU TI Connecting disorder and magnetic properties in CoFe thin films SO APPLIED PHYSICS LETTERS LA English DT Article ID X-RAY; GIANT MAGNETORESISTANCE; SCATTERING; SUPERLATTICES; MULTILAYERS; ROUGHNESS AB Through a direct study of the chemical and magnetic interfacial disorder in conjunction with magnetic property measurements, evidence is presented that the grain size is the ultimate factor in determining the magnetic coercivity in CoFe thin film structures. (C) 2000 American Institute of Physics. [S0003-6951(00)02818-7]. C1 Argonne Natl Lab, Expt Facil Div, Argonne, IL 60439 USA. USN, Res Lab, Div Sci Mat, Washington, DC 20375 USA. RP Freeland, JW (reprint author), Argonne Natl Lab, Expt Facil Div, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 24 TC 12 Z9 12 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 1 PY 2000 VL 76 IS 18 BP 2603 EP 2605 DI 10.1063/1.126422 PG 3 WC Physics, Applied SC Physics GA 307PY UT WOS:000086662900040 ER PT J AU Avrekh, M Monteiro, OR Brown, IG AF Avrekh, M Monteiro, OR Brown, IG TI Electrical resistivity of vacuum-arc-deposited platinum thin films SO APPLIED SURFACE SCIENCE LA English DT Article DE resistivity; vacuum arc deposition; platinum ID GRAIN-BOUNDARY SCATTERING; METAL-FILMS; CARBIDE; CARBON; MODEL AB We report on our investigations of the electrical resistivity of very thin platinum films, with thickness in the range from 2.6 to 19 nm, formed using a filtered vacuum are plasma deposition method. We find that the resistivity of these films can be well described by a grain-boundary scattering model, especially for thickness less than similar to 5 nm. We also find that the grain size, and consequently the resistivity of the deposited film, is a function of the ion deposition energy, with measured grain size varying from similar to 8 nm for ion deposition energy of 100 eV up to similar to 11 nm at 2.2 keV. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Avrekh, M (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. NR 21 TC 34 Z9 34 U1 4 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 2000 VL 158 IS 3-4 BP 217 EP 222 DI 10.1016/S0169-4332(00)00021-0 PG 6 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 330KT UT WOS:000087961800005 ER PT J AU Boettcher, S Percus, A AF Boettcher, S Percus, A TI Nature's way of optimizing SO ARTIFICIAL INTELLIGENCE LA English DT Article DE combinatorial optimization; heuristics; local search; graph partitioning; traveling salesman problem; self-organized criticality ID SELF-ORGANIZED CRITICALITY; TRAVELING SALESMAN PROBLEM; OPTIMIZATION; EVOLUTION; MODEL; ALGORITHM AB We propose a general-purpose method for finding high-quality solutions to hard optimization problems, inspired by self-organizing processes often found in nature. The method, called Extremal Optimization, successively eliminates extremely undesirable components of sub-optimal solutions. Drawing upon models used to simulate far-from-equilibrium dynamics, it complements approximation methods inspired by equilibrium statistical physics, such as Simulated Annealing. With only one adjustable parameter, its performance proves competitive with, and often superior to, more elaborate stochastic optimization procedures. We demonstrate it here on two classic hard optimization problems: graph partitioning and the traveling salesman problem. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Clark Atlanta Univ, CTSPS, Atlanta, GA 30314 USA. Emory Univ, Dept Phys, Atlanta, GA 30322 USA. RP Boettcher, S (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Boettcher, Stefan/G-2640-2010 OI Boettcher, Stefan/0000-0003-1273-6771 NR 32 TC 152 Z9 159 U1 2 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0004-3702 J9 ARTIF INTELL JI Artif. Intell. PD MAY PY 2000 VL 119 IS 1-2 BP 275 EP 286 DI 10.1016/S0004-3702(00)00007-2 PG 12 WC Computer Science, Artificial Intelligence SC Computer Science GA 324CZ UT WOS:000087605400009 ER PT J AU Aldering, G Knop, R Nugent, P AF Aldering, G Knop, R Nugent, P TI The rise times of high- and low-redshift Type Ia supernovae are consistent SO ASTRONOMICAL JOURNAL LA English DT Article DE cosmology : observations; supernovae : general ID GALAXIES; CONSTANT; LAMBDA; 1991T; 1994D; OMEGA AB We present a self-consistent comparison of the rise times for low- and high-redshift Type Ia supernovae. Following previous studies, the early light curve is modeled using a t(2) law, which is then mated with a modified Leibundgut template light curve. The best-fit t(2) law is determined for ensemble samples of low- and high-redshift supernovae by fitting simultaneously for all light-curve parameters for all supernovae in each sample. Our method fully accounts for the nonnegligible covariance among the lightcurve fitting parameters, which previous analyses have neglected. Contrary to recent results by Riess et al., we find fair to good agreement between the rise times of the low- and high-redshift Type Ia supernovae. The uncertainty in the rise time of the high-redshift Type Ia supernovae is presently quite large (roughly +/-1.2 days statistical), making any search for evidence of evolution based on a comparison of rise times premature. Furthermore, systematic effects on rise-time determinations from the high-redshift observations, due to the form of the late-time light curve and the manner in which the light curves of these supernovae were sampled, can bias the high-redshift rise-time determinations by up to (+3.6)(-1.9) days under extreme situations. The peak brightnesses-used for cosmology-do not suffer any significant bias, nor any significant increase in uncertainty. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Aldering, G (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Mail Stop 50-232,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 30 TC 45 Z9 45 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2000 VL 119 IS 5 BP 2110 EP 2117 DI 10.1086/301344 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 318YB UT WOS:000087311300008 ER PT J AU Alcock, C Allsman, RA Alves, DR Axelrod, TS Basu, A Becker, AC Bennett, DP Cook, KH Drake, AJ Freeman, KC Geha, M Griest, K King, L Lehner, MJ Marshall, SL Minniti, D Nelson, CA Peterson, BA Popowski, P Pratt, MR Quinn, PJ Stubbs, CW Sutherland, W Tomaney, AB Vandehei, T Welch, DL AF Alcock, C Allsman, RA Alves, DR Axelrod, TS Basu, A Becker, AC Bennett, DP Cook, KH Drake, AJ Freeman, KC Geha, M Griest, K King, L Lehner, MJ Marshall, SL Minniti, D Nelson, CA Peterson, BA Popowski, P Pratt, MR Quinn, PJ Stubbs, CW Sutherland, W Tomaney, AB Vandehei, T Welch, DL TI The MACHO project 9 million star color-magnitude diagram of the Large Magellanic Cloud SO ASTRONOMICAL JOURNAL LA English DT Review DE cepheids; color-magnitude diagrams; galaxies : stellar content; Magellanic Clouds; RR Lyrae variable; stars : evolution; stars : horizontal-branch; stars : variables : other; supergiants ID ASYMPTOTIC GIANT BRANCH; RR-LYRAE VARIABLES; GALACTIC GLOBULAR-CLUSTERS; INTERMEDIATE-MASS STARS; STELLAR POPULATIONS; EVOLUTIONARY SEQUENCES; RADIATIVE OPACITIES; HORIZONTAL BRANCHES; LUMINOSITY FUNCTION; FORMATION HISTORY AB We present a 9 million star color-magnitude diagram (9M CMD) of the Large Magellanic Cloud (LMC) bar. The 9M CMD reveals a complex superposition of different-age and -metallicity stellar populations, with important stellar evolutionary phases occurring over 3 orders of magnitude in number density. First, we count the nonvariable red and blue supergiants and the associated Cepheid variables and measure the stellar effective temperatures defining the Cepheid instability strip. Lifetime predictions of stellar evolution theory are tested, with implications for the origin of low-luminosity Cepheids. The highly evolved asymptotic giant branch (AGB) stars in the 9M CMD have a bimodal distribution in brightness, which we interpret as discrete old populations (greater than or similar to 1 Gyr). The faint AGE sequence may be metal-poor and very old. Comparing the mean properties of giant branch and horizontal-branch (HB) stars in the 9M CMD with those of clusters, we identify NGC 411 and M3 as templates for the admixture of old stellar populations in the bar. However, there are several indications that the old and metal-poor field population has a red HE morphology: the RR Lyrae variables lie preferentially on the red edge of the instability strip, the AGE bump is very red, and the ratio of AGE bump stars to RR Lyrae variables is quite large. If the HE second parameter is age, the old and metal-poor field population in the bar likely formed after the oldest LMC clusters. Lifetime predictions of stellar evolution theory lead us to associate a significant fraction of the similar to 1 million red HE clump giants in the 9M CMD with the same old and metal-poor population producing the RR Lyrae stars and the AGE bump. In this case, compared with the age-dependent luminosity predictions of stellar evolution theory, the red HE clump is too bright relative to the RR Lyrae stars and AGE bump. Last, we show that the surface density profile of RR Lyrae variables is fitted by an exponential, favoring a disklike rather than a spheroidal distribution. We conclude that the age of the LMC disk is probably similar to the age of the Galactic disk. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Australian Natl Univ, ANU Supercomp Facil, Canberra, ACT 0200, Australia. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Sheffield, Dept Phys & Astron, Sheffield S3 7RH, S Yorkshire, England. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Oxford, Dept Phys, Oxford OX1 3RH, England. McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RP Alcock, C (reprint author), Lawrence Livermore Natl Lab, 7000 E Ave, Livermore, CA 94550 USA. RI Stubbs, Christopher/C-2829-2012; Quinn, Peter/B-3638-2013; OI Stubbs, Christopher/0000-0003-0347-1724; Lehner, Matthew/0000-0003-4077-0985 NR 117 TC 77 Z9 77 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD MAY PY 2000 VL 119 IS 5 BP 2194 EP 2213 DI 10.1086/301326 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 318YB UT WOS:000087311300015 ER PT J AU Auer, LH Standish, EM AF Auer, LH Standish, EM TI Astronomical refraction: Computational method for all zenith angles SO ASTRONOMICAL JOURNAL LA English DT Article DE methods : numerical AB It is shown that the problem of computing astronomical refraction for any value of the zenith angle may be reduced to a simple, nonsingular, numerical quadrature when the proper choice is made for the independent variable of integration. The angle between the radius vector and the light ray is such a choice. The implementation of the quadrature method is discussed in its general form and illustrated by means of an application to a piecewise polytropic atmosphere. The flexibility, simplicity, and computational efficiency of the method are evident. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Auer, LH (reprint author), Univ Calif Los Alamos Natl Lab, Mail Stop B226, Los Alamos, NM 87545 USA. NR 4 TC 31 Z9 31 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAY PY 2000 VL 119 IS 5 BP 2472 EP 2474 DI 10.1086/301325 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 318YB UT WOS:000087311300042 ER PT J AU Haiman, Z Abel, T Rees, MJ AF Haiman, Z Abel, T Rees, MJ TI The radiative feedback of the first cosmological objects SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; diffuse radiation; early universe; galaxies : formation; molecular processes; radiative transfer ID DWARF GALAXIES; HIGH-REDSHIFT; REIONIZATION; CLOUDS; MODEL AB hierarchical models of structure formation, an early cosmic UV background (UVB) is produced by the small (T(vir) less than or similar to 10(4) K) halos that collapse before reionization. The UVB at energies below 13.6 eV suppresses the formation of stars or black holes inside small halos by photodissociating their only cooling agent, molecular H(2). We self-consistently compute the buildup of the early UVB in Press-Schechter models, coupled with H(2) photodissociation both in the intergalactic medium (IGM) and inside virialized halos. We find that the intergalactic H(2) has a negligible effect on the UVB, both because its initial optical depth is small (less than or similar to 0.1) and because it is photodissociated at an early stage. If the UV sources in the first collapsed halos are stars, then their UV flux suppresses further star formation inside small halos. This results in a pause in the buildup of the UVB, and reionization is delayed until larger halos (T(vir) greater than or similar to 10(4) K) collapse. If the small halos host miniquasars with hard spectra extending to similar to 1 keV, then their X-rays balance the effects of the WE, the negative feedback does not occur, and reionization could be caused by the small halos. C1 NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Lab Computat Astrophys, Urbana, IL 61801 USA. Max Planck Inst Astrophys, D-85748 Garching, Germany. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Haiman, Z (reprint author), NASA, Fermi Natl Accelerator Lab, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. NR 31 TC 266 Z9 266 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAY 1 PY 2000 VL 534 IS 1 BP 11 EP 24 DI 10.1086/308723 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 316TC UT WOS:000087183300002 ER PT J AU Pesole, G Liuni, S D'Souza, M AF Pesole, G Liuni, S D'Souza, M TI PatSearch: a pattern matcher software that finds functional elements in nucleotide and protein sequences and assesses their statistical significance SO BIOINFORMATICS LA English DT Article ID MESSENGER-RNA; RECOGNITION; PREDICTION AB Motivation: The identification of sequence patterns involved in gene regulation and expression is a major challenge in molecular biology. In this paper we describe a novel algorithm and the software for searching nucleotide and protein sequences for complex nucleotide patterns including potential secondary structure Elements, also allowing for mismatches/mispairings below a user fixed threshold, and assessing the statistical significance of their occurrence through a Markov chain simulation. Results: The application of the proposed algorithm allowed the identification of some functional elements, such as the Iron Responsive Element, the Histone stem-loop structure and the Selenocysteine Insertion Sequence, located in the mRNA untranslated regions of post-transcriptionally regulated genes with the assessment of sensitivity and selectivity of the searching method. C1 Univ Milan, Dipartimento Fisiol & Biochim Gen, I-20133 Milan, Italy. CNR, Ctr Studio Mitocondri & Metab Energet, I-70126 Bari, Italy. Argonne Natl Lab, Div Math & Comp Sci, Argonne, IL 60439 USA. RP Pesole, G (reprint author), Univ Milan, Dipartimento Fisiol & Biochim Gen, Via Celoria 26, I-20133 Milan, Italy. RI Pesole, Graziano/C-1408-2009; Pesole, Graziano/E-9051-2014 OI Pesole, Graziano/0000-0003-3663-0859; Pesole, Graziano/0000-0003-3663-0859 NR 11 TC 63 Z9 65 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1367-4803 J9 BIOINFORMATICS JI Bioinformatics PD MAY PY 2000 VL 16 IS 5 BP 439 EP 450 DI 10.1093/bioinformatics/16.5.439 PG 12 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Computer Science, Interdisciplinary Applications; Mathematical & Computational Biology; Statistics & Probability SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Computer Science; Mathematical & Computational Biology; Mathematics GA 338VU UT WOS:000088444600004 PM 10871266 ER PT J AU Irving, TC Maughan, DW AF Irving, TC Maughan, DW TI In vivo X-ray diffraction of indirect flight muscle from Drosophila melanogaster SO BIOPHYSICAL JOURNAL LA English DT Article ID STRIATED-MUSCLE; FILAMENT LATTICE; THICK FILAMENTS; LIGHT-CHAIN AB Small-angle x-ray diffraction from isolated muscle preparations is commonly used to obtain time-resolved structural information during contraction. We extended this technique to the thoracic flight muscles of living fruit flies, at rest and during tethered flight, Precise measurements at 1-ms time resolution indicate that the myofilament lattice spacing does not change significantly during oscillatory contraction. This result is consistent with the notion that a net radial force maintains the thick filaments at an equilibrium interfilament spacing of similar to 56 nm throughout the contractile cycle. Transgenic flies with amino-acid substitutions in the conserved phosphorylation site of the myosin regulatory light chain (RLC) exhibit structural abnormalities that can explain their flight impairment. The I-20/I-10 equatorial intensity ratio of the mutant fly is 35% less than that of wild type, supporting the hypothesis that myosin heads that lack phosphorylated RLC remain close to the thick filament backbone. This new experimental system facilitates investigation of the relation between molecular structure and muscle function in living organisms. C1 IIT, Dept Biol Chem & Phys Sci, Chicago, IL 60616 USA. IIT, Biophys Collaborat Access Team, Ctr Synchrotron Radiat Res, Chicago, IL 60616 USA. Univ Vermont, Dept Physiol & Mol Biophys, Burlington, VT 05405 USA. RP Irving, TC (reprint author), IIT, Dept Biol Chem & Phys Sci, 3101 S Dearborn St, Chicago, IL 60616 USA. RI ID, BioCAT/D-2459-2012 FU NCRR NIH HHS [RR08630] NR 21 TC 32 Z9 32 U1 0 U2 6 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD MAY PY 2000 VL 78 IS 5 BP 2511 EP 2515 PG 5 WC Biophysics SC Biophysics GA 311PF UT WOS:000086892500030 PM 10777748 ER PT J AU Evans, BR Gilman, AK Cordray, K Woodward, J AF Evans, BR Gilman, AK Cordray, K Woodward, J TI Mechanism of substrate hydrolysis by a thermophilic endoglucanase from Thermotoga maritima SO BIOTECHNOLOGY LETTERS LA English DT Article DE cellulase; hyperthermophile; mechanism; synergy ID ARCHAEON PYROCOCCUS-FURIOSUS; BETA-GLUCOSIDASE; CELLULASE; PURIFICATION; PROTEINS; ENZYMES AB A cellulase from the thermophile, Thermotoga maritima, hydrolyzed oligosaccharide substrates by an exoglucanase mode of action but acted as an endoglucanase to rapidly reduce the Viscosity of the soluble polysaccharides carboxymethylcellulose and barley beta-glucan. The V-max for hydrolysis of the substrate, p-nitrophenyl beta-D-cellobioside, was 42 mu mol min(-1) (mg protein)(-1), while that for barley beta-glucan was 637. The enzyme had little activity on crystalline cellulose. C1 Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. RP Evans, BR (reprint author), Oak Ridge Natl Lab, Div Chem Technol, Oak Ridge, TN 37831 USA. NR 23 TC 10 Z9 11 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0141-5492 J9 BIOTECHNOL LETT JI Biotechnol. Lett. PD MAY PY 2000 VL 22 IS 9 BP 735 EP 740 DI 10.1023/A:1005656203233 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 331RY UT WOS:000088033500003 ER PT J AU Rho, JY Zioupos, P Currey, JD Pharr, GM AF Rho, JY Zioupos, P Currey, JD Pharr, GM TI Untitled - Response SO BONE LA English DT Letter C1 Univ Memphis, Dept Biomed Engn, Memphis, TN 38152 USA. Cranfield Univ, Dept Mat & Med Sci, Shrivenham, England. Univ York, Dept Biol, York YO1 5DD, N Yorkshire, England. Univ Tennessee, Dept Mat Sci, Knoxville, TN USA. Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN USA. RP Rho, JY (reprint author), Univ Memphis, Dept Biomed Engn, Memphis, TN 38152 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 8756-3282 J9 BONE JI Bone PD MAY PY 2000 VL 26 IS 5 BP 545 EP 546 DI 10.1016/S8756-3282(00)00267-2 PG 2 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 309WU UT WOS:000086792900020 ER PT J AU Goff, F McMurtry, GM Counce, D Simac, JA Roldan-Manzo, AR Hilton, DR AF Goff, F McMurtry, GM Counce, D Simac, JA Roldan-Manzo, AR Hilton, DR TI Contrasting hydrothermal activity at Sierra Negra and Alcedo volcanoes, Galapagos Archipelago, Ecuador SO BULLETIN OF VOLCANOLOGY LA English DT Article DE Galapagos; volcanic gases; gas geochemistry; isotope geochemistry; geothermal systems; Sierra Negra; Alcedo ID MOUNT ST-HELENS; VALLES CALDERA; KILAUEA-VOLCANO; ISOTOPE RATIOS; NEW-MEXICO; CARBON RELATIONSHIPS; GEOTHERMAL SYSTEM; MANTLE PLUME; GASES; WATERS AB Sierra Negra and Alcedo volcanoes are adjacent tholeiitic shields with summit calderas located on Isabela Island in the Galapagos Archipelago. Although basaltic eruptions have characterized the evolution of these volcanoes, Alcedo has produced minor volumes of rhyolite lavas and tephras dated at approximately 100 ka. Fumaroles and ephemeral acid-sulfate seeps occur within the calderas of both volcanoes, whereas neutral-chloride and diluted steam-heated hot springs are absent. Fumarolic activity inside Sierra Negra (Mina Azufral) is fault controlled along the west margin of a horst and discharge temperatures are less than or equal to 210 degrees C (January to February 1995). Water content of the total gas is approximately 75 mol.%, and noncondensible gases consist of approximately 97 mol.% CO2 and approximately 85% SO2 of the total sulfur gas. Relative amounts of He, Ar, and N-2 show a distinct hot-spot signature (He-3/ He-4=17.4+/-0.3 R-A) The delta(13)C-CO2 is approximately -3.6 parts per thousand and delta(34)S(T) is approximately +3.3 parts per thousand. The delta D/ delta(18)O of fumarole H2O indicates steam separation from local meteoric waters whose estimated minimum mean residence time from H-3 analyses is less than or equal to 40 years. Fumarolic activity at. Alcedo is controlled by a caldera-margin fault containing at least: seven hydrothermal explosion craters, and by an intracaldera rhyolite vent. Two explosion craters which formed in 1993-1994 produce approximately 15 m(3)/s of steam, yet discharge temperatures are less than or equal to 97 degrees C. Water content of the total gas is 95-97 mol.%, noncondensible gas is 92-98 mol.% CO2, and sulfur gas is dominated by H2S. Relative amounts of He, Ar, and N-2 show extensive mixing between hot spot and air or air-saturated meteoric water components but the average >He-3/ He-4=15.5+/-0.4 R-A. The delta(13)C-CO2 is approximately -3.5 parts per thousand and delta(34)S(T) is approximately -0.8 parts per thousand. The delta D/ delta(18)O of fumarole steam indicates separation from a homogeneous reservoir that is enriched 3-5 parts per thousand in O-18 compared with local meteoric water. H-3 indicates that this reservoir water has a maximum mean residence time of approximately 400 years and empirical gas geothermometry indicates a reservoir temperature of 260-320 degrees C. The intracaldera hydrothermal reservoir in Alcedo is probably capable of producing up to 150 MW; however, environmental concerns as well as lack of infrastructure and power users will limit the development of this resource. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Hawaii, SOEST, Honolulu, HI 96822 USA. UNOCAL Corp, Philippines, Sugar Land, TX 77478 USA. INDE, Guatemala City, Guatemala. Vrije Univ Amsterdam, Dept Earth Sci, NL-1081 HV Amsterdam, Netherlands. RP Goff, F (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Hilton, David/B-7611-2008 NR 55 TC 30 Z9 30 U1 0 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0258-8900 J9 B VOLCANOL JI Bull. Volcanol. PD MAY PY 2000 VL 62 IS 1 BP 34 EP 52 DI 10.1007/s004450050289 PG 19 WC Geosciences, Multidisciplinary SC Geology GA 320KJ UT WOS:000087400100003 ER PT J AU Moser, MJ Bigbee, WL Grant, SG Emond, MJ Langlois, RG Jensen, RH Oshima, J Monnat, RJ AF Moser, MJ Bigbee, WL Grant, SG Emond, MJ Langlois, RG Jensen, RH Oshima, J Monnat, RJ TI Genetic instability and hematologic disease risk in Werner syndrome patients and heterozygotes SO CANCER RESEARCH LA English DT Article ID PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA; VIVO SOMATIC MUTATION; GLYCOPHORIN-A LOCUS; BLOOMS-SYNDROME; ATAXIA-TELANGIECTASIA; VARIANT ERYTHROCYTES; INCREASED FREQUENCY; FANCONI-ANEMIA; LYMPHOCYTES; HELICASES AB Werner syndrome (WRN) is an uncommon autosomal recessive disease in which progeroid features are associated with genetic instability and an elevated risk of neoplasia. We have used the glycophorin A (GPA) somatic cell mutation assay to analyze genetic instability in vivo in WRN patients acid heterozygotes. GPA variant frequencies were determined for 11 WRN patients and for 10 heterozygous family members who collectively carry 10 different WRN mutations. Genetic instability as measured by GPA O/N allele loss variant frequency was significantly increased, and this increase was strongly age-dependent in WRN patients. CPA O/N allele loss variants were also significantly elevated in heterozygous family members, thus providing the first evidence for in vivo genetic instability in heterozygous carriers in an autosomal recessive genetic instability syndrome. Our results and comparable data on other human genetic instability syndromes allow an estimate of the level of genetic instability that increases the risk of human bone marrow dysfunction or neoplasia. C1 Univ Washington, Dept Pathol, Seattle, WA 98195 USA. Univ Washington, Dept Biostat, Seattle, WA 98195 USA. Univ Pittsburgh, Grad Sch Publ Hlth, Ctr Environm & Occupat Hlth & Toxicol, Pittsburgh, PA 15238 USA. Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Univ Calif San Francisco, Ctr Canc, Dept Lab Med, San Francisco, CA 94143 USA. RP Monnat, RJ (reprint author), Univ Washington, Dept Pathol, Box 357705, Seattle, WA 98195 USA. RI Grant, Stephen/D-6984-2014 OI Grant, Stephen/0000-0002-9236-0913 FU NCI NIH HHS [R01 CA48022, N01-CP-50520, R29 CA77607] NR 45 TC 40 Z9 41 U1 0 U2 0 PU AMER ASSOC CANCER RESEARCH PI BIRMINGHAM PA PO BOX 11806, BIRMINGHAM, AL 35202 USA SN 0008-5472 J9 CANCER RES JI Cancer Res. PD MAY 1 PY 2000 VL 60 IS 9 BP 2492 EP 2496 PG 5 WC Oncology SC Oncology GA 311AM UT WOS:000086862100031 PM 10811130 ER PT J AU Kim, DW Sovak, MA Zanieski, G Nonet, G Romieu-Mourez, R Lau, AW Hafer, LJ Yaswen, P Stampfer, M Rogers, AE Russo, J Sonenshein, GE AF Kim, DW Sovak, MA Zanieski, G Nonet, G Romieu-Mourez, R Lau, AW Hafer, LJ Yaswen, P Stampfer, M Rogers, AE Russo, J Sonenshein, GE TI Activation of NF-kappa B/Rel occurs early during neoplastic transformation of mammary cells SO CARCINOGENESIS LA English DT Article ID TUMOR-NECROSIS-FACTOR; C-MYC PROMOTER; MURINE B-CELLS; BREAST-CANCER; EPITHELIAL-CELLS; INDUCED APOPTOSIS; ALPHA; EXPRESSION; LINES; INHIBITION AB NF-kappa B/Rel is a family of transcription factors which are expressed in all cells; however, in most non-B cells, they are sequestered in the cytoplasm in inactive complexes with specific inhibitory proteins, termed I kappa Bs. We have recently shown that NF-kappa B/Rel factors are aberrantly activated in human breast cancer and rodent mammary tumors, and function to promote tumor cell survival and proliferation. Here, we have examined the time-course of induction of NF-kappa B/Rel factors upon carcinogen treatment of female Sprague-Dawley (S-D) rats in vivo and in human mammary epithelial cells (HMECs) in culture. We observed that NF-kappa B/Rel activation is an early event, occurring prior to malignant transformation. In S-D rats, increased NF-kappa B/ Rel binding was detected in nuclear extracts of mammary glands from 40% of animals 3 weeks post-treatment with 15 mg/kg 7,12-dimethylbenz[a]anthracene (DMBA); this is prior to formation of tumors which normally begin to be detected after 7-9 weeks. In non-tumorigenic MCF-10F cells, in vitro malignant transformation upon treatment with either DMBA or benzo[a]pyrene (B[a]P) resulted in a 4- to 12-fold increase in activity of classical NF-kappa B (p65/ p50), NF-kappa B induction was corrrelated with a decrease in the stability of the NF-kappa B-specific inhibitory protein I kappa B-alpha. Ectopic expression of the transactivating p65 subunit of NF-kappa B in MCF-10F cells induced the c-myc oncogene promoter, which is driven by two NF-kappa B elements, and endogenous c-Myc levels. Furthermore, reduction mammoplasty-derived HMECs, immortalized following B[a]P exposure, showed dysregulated induction of classical NF-kappa B prior to malignant transformation. Together these findings suggest that activation of NF-kappa B plays an early, critical role in the carcinogen-driven transformation of mammary glands. C1 Boston Univ, Sch Med, Dept Biochem, Boston, MA 02118 USA. Boston Univ, Sch Med, Dept Pathol & Lab Med, Boston, MA 02118 USA. Boston Univ, Sch Med, Program Res Womens Hlth, Boston, MA 02118 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Fox Chase Canc Ctr, Breast Canc Res Lab, Philadelphia, PA 19111 USA. RP Sonenshein, GE (reprint author), Boston Univ, Sch Med, Dept Biochem, 715 Albany St, Boston, MA 02118 USA. FU NCI NIH HHS [CA82742, CA24844] NR 47 TC 114 Z9 117 U1 0 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD MAY PY 2000 VL 21 IS 5 BP 871 EP 879 DI 10.1093/carcin/21.5.871 PG 9 WC Oncology SC Oncology GA 315WZ UT WOS:000087137100003 PM 10783306 ER PT J AU Buchko, GW Hess, NJ Kennedy, MA AF Buchko, GW Hess, NJ Kennedy, MA TI Cadmium mutagenicity and human nucleotide excision repair protein XPA: CD, EXAFS and H-1/N-15-NMR spectroscopic studies on the zinc(II)- and cadmium(II)-associated minimal DNA-binding domain (M98-F219) SO CARCINOGENESIS LA English DT Article ID ABSORPTION FINE-STRUCTURE; MAMMALIAN-CELLS; CARBOXYPEPTIDASE-A; DAMAGE-RECOGNITION; ESCHERICHIA-COLI; NMR; PEPTIDES; RPA; PHYTOCHELATIN; SPECIFICITY AB Human XPA is a 31 kDa protein involved in nucleotide excision repair (NER), a ubiquitous, multi-enzyme pathway responsible for processing multiple types of DNA damage in the eukaryotic genome. A zinc-associated, C4-type motif (C105-X-2-C108-X-17-C126-X-2-C129) located in the minimal DNA-binding region (M98-F219) of XPA. (XPA-MBD) is essential for damaged DNA recognition, Cadmium is a known carcinogen and can displace the zinc in many metal-binding proteins, It has been suggested that the carcinogenic properties of cadmium may result from structural changes effected in XPA when Cd2+ is substituted for Zn2+ in the metal-binding site. The solution structure of XPA-MBD containing zinc(Ir) has recently been determined [Buchko ef nl,? (1998) Nucleic Acids Res., 26, 2779-2788; Buchko et al,, (1999) Biochemistry, 38, 15116-15128], To assess the effects of cadmium(II) substitution on the structure of XPA-MBD, XPA-MBD was expressed in minimal medium supplemented with cadmium acetate to yield a protein that was almost exclusively (>95%) associated with cadmium(II) (CdXPA-MBD). Extended X-ray absorption fine structure spectra collected on ZnXPA-MBD and CdXPA-MBD in frozen (77 K) 15% aqueous glycerol solution show that the metal is coordinated to the sulfur atoms of four cysteine residues with an average metal-sulfur bond length of 2.34 +/- 0.01 and 2.54 +/- 0.01 Angstrom, respectively. Comparison of the circular dichroism, two-dimensional H-1,N-15-HSQC, and three-dimensional N-15-edited HSQC-NOESY spectra of ZnXPA-MBD and CdXPA-MBD show that there are no structural differences between the two proteins. The absence of major structural changes upon substituting cadmium(II) for zinc(II) in XPA suggests that cadmium-induced mutagenesis is probably not due to structural perturbations to the zinc-binding core of XPA. C1 Pacific NW Lab, Environm Mol Sci Lab & Biogeochem Resources, Richland, WA 99352 USA. RP Kennedy, MA (reprint author), Pacific NW Lab, Environm Mol Sci Lab & Biogeochem Resources, POB 999, Richland, WA 99352 USA. RI Buchko, Garry/G-6173-2015; OI Buchko, Garry/0000-0002-3639-1061; Hess, Nancy/0000-0002-8930-9500 NR 61 TC 29 Z9 36 U1 1 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD MAY PY 2000 VL 21 IS 5 BP 1051 EP 1057 DI 10.1093/carcin/21.5.1051 PG 7 WC Oncology SC Oncology GA 315WZ UT WOS:000087137100029 PM 10783332 ER PT J AU Benedict, D AF Benedict, D TI Woman at the helm SO CHEMICAL & ENGINEERING NEWS LA English DT Letter C1 Natl Energy Technol Lab, Morgantown, WV USA. RP Benedict, D (reprint author), Natl Energy Technol Lab, Morgantown, WV USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0009-2347 J9 CHEM ENG NEWS JI Chem. Eng. News PD MAY 1 PY 2000 VL 78 IS 18 BP 8 EP 8 PG 1 WC Chemistry, Multidisciplinary; Engineering, Chemical SC Chemistry; Engineering GA 309KM UT WOS:000086767100002 ER PT J AU Lightstone, FC Prieto, MC Singh, AK Piqueras, MC Whittal, RM Knapp, MS Balhorn, R Roe, DC AF Lightstone, FC Prieto, MC Singh, AK Piqueras, MC Whittal, RM Knapp, MS Balhorn, R Roe, DC TI Identification of novel small molecule ligands that bind to tetanus toxin SO CHEMICAL RESEARCH IN TOXICOLOGY LA English DT Article ID IONIZATION MASS-SPECTROMETRY; STRUCTURE-BASED DESIGN; ELECTROSPRAY-IONIZATION; AUTOMATED DOCKING; RECEPTOR; GANGLIOSIDES; NEUROTOXINS; INHIBITORS; COMPLEXES; MEMBRANES AB Tetanus toxin belongs to a family of clostridial protein neurotoxins for which there are no known antidotes, Another closely related member of this family, botulinum toxin, is being used with increasing frequency by physicians to treat severe muscle disorders. Botulinum toxin has also been produced in large quantities by terrorists for use as a biological weapon. To identify small molecule ligands that might bind to the targeting domain of tetanus and botulinum toxins and to facilitate the design of inhibitors and new reagents for their detection, molecular docking calculations were used to screen a large database of compounds for their potential to bind to the C fragment of tetanus toxin. Eleven of the predicted ligands were assayed by electrospray ionization mass spectrometry (ESI-MS) for binding to the tetanus toxin C fragment, and five ligands (45%) were found to bind to the protein. One of these compounds, doxorubicin, was observed to have strong hydrophobic interactions with the C fragment. To check the ligands for their ability to compete with ganglioside binding, each was also tested using a GT1b liposome assay. Doxorubicin was the only ligand found to competitively bind the tetanus toxin C fragment with an appreciable binding constant (9.4 mu M). C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. Univ Calif Lawrence Livermore Natl Lab, Chem & Mat Sci Directorate, Livermore, CA 94550 USA. Sandia Natl Labs, Biosyst Res Dept, Livermore, CA 94551 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, Mass Spect Facil, San Francisco, CA 94143 USA. RP Roe, DC (reprint author), Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94550 USA. FU NCRR NIH HHS [RR01614] NR 47 TC 25 Z9 25 U1 1 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0893-228X J9 CHEM RES TOXICOL JI Chem. Res. Toxicol. PD MAY PY 2000 VL 13 IS 5 BP 356 EP 362 DI 10.1021/tx000009e PG 7 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Toxicology SC Pharmacology & Pharmacy; Chemistry; Toxicology GA 315KZ UT WOS:000087114100006 PM 10813652 ER PT J AU Sasaki, DY Alam, TM AF Sasaki, DY Alam, TM TI Solid-state P-31 NMR study of phosphonate binding sites in guanidine-functionalized, molecular imprinted silica xerogels SO CHEMISTRY OF MATERIALS LA English DT Article ID SYNTHETIC-POLYMERS; RECOGNITION; COMPLEXATION; CATALYSIS; TEMPLATES; ACIDS; PH AB Phosphonate binding sites in guanidine and ammonium surface-functionalized silica xerogels were prepared via the molecular imprinting technique and characterized using solid-state P-31 MAS NMR. One-point, two-point, and nonspecific host-guest interactions between phenylphosphonic acid (PPA) and the functionalized gels were distinguished by characteristic chemical shifts of the observed absorption peaks. Using solid-state as well as solution-phase NMR analyses, absorptions observed at 15.5 and 6.5 ppm were identified as resulting from the 1:1 (one-point) and 2:1 (two-point) guanidine to phosphonate interactions, respectively. Similar absorptions were observed with the ammonium functionalized gels. By examining the host-guest interactions within the gels, the efficiency of the molecular imprinting procedure with regard to the functional monomer-to-template interaction could be readily assessed. Template removal followed by substrate adsorption studies conducted on the guanidine-functionalized gels provided a method to evaluate the binding characteristics of the receptor sites to a phosphonate substrate. During these experiments, Si-29 and P-31 MAS NMR acted as diagnostic monitors to identify structural changes occurring in the gel matrix and at the receptor site from solvent-mediated processes. C1 Sandia Natl Labs, Biomol Mat & Interfaces Dept, Albuquerque, NM 87185 USA. Sandia Natl Labs, Organ Mat Dept, Albuquerque, NM 87185 USA. RP Sasaki, DY (reprint author), Sandia Natl Labs, Biomol Mat & Interfaces Dept, POB 5800, Albuquerque, NM 87185 USA. NR 38 TC 43 Z9 45 U1 0 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 2000 VL 12 IS 5 BP 1400 EP 1407 DI 10.1021/cm990737r PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 315WW UT WOS:000087136800032 ER PT J AU Norby, P Hanson, JC Fitch, AN Vaughan, G Flaks, L Gualtieri, A AF Norby, P Hanson, JC Fitch, AN Vaughan, G Flaks, L Gualtieri, A TI Formation of alpha-eucryptite, LiAlSiO4: An in-situ synchrotron X-ray powder diffraction study of a high temperature hydrothermal synthesis SO CHEMISTRY OF MATERIALS LA English DT Article ID CRYSTAL-STRUCTURE; ZEOLITE LI-A(BW); CRYSTALLIZATION; CONVERSION; CHEMISTRY AB Hydrothermal conversion of zeolite Li-A(BW), LiAlSiO4 H2O, into alpha-eucryptite, LiAlSiO4, occurs at temperatures above 350 degrees C. We report here the first in-situ study of a high-temperature hydrothermal synthesis using time-resolved powder diffraction. The following hydrothermal reactions were studied: 4 M NaNO3:LiAlSiO4 [ABW] --> Li(Na)AlSiO4 H2O [ABW] --> Na(6)Al(6)Si6O(24).2NaNO(3) [SOD]; 2 M LiCl:LiAlSiO4 H2O [ABW] --> alpha-LiAlSiO4; 2 M LiCl:LiAlSiO4[ABW] --> LiAlSiO4.H2O [ABW] --> alpha-LiAlSiO4. The hydrothermal syntheses were performed in stainless steel capillaries. To maintain hydrothermal conditions, a hydraulic pressure of 2-300 atm was applied. Synchrotron X-ray radiation with energies of 35-40 keV was used in order to penetrate the steel capillaries. Room temperature Imaging Plate powder diffraction data were collected on a sample of zeolite Li-A(BW) contained in a steel capillary in an aqueous solution at 200 atm. pressure. With the use of a 10 min exposure, it was possible successfully to refine the crystal structure of zeolite Li-A(BW) using Rietveld refinement. Angle dispersive time-resolved in-situ powder diffraction patterns were collected using a Translating Imaging Plate (TIP) camera. Crystallization and degradation curves for the high-temperature hydrothermal conversion experiments were determined using integrated intensities of selected diffraction lines. The kinetic curves were analyzed using first-order rate expressions. C1 Univ Oslo, Dept Chem, N-0315 Oslo, Norway. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. European Synchrotron Radiat Facil, F-38043 Grenoble, France. Brookhaven Natl Lab, Natl Synchrotron Light Source Dept, Upton, NY 11973 USA. Univ Modena, Dipartimento Sci Terra, I-41100 Modena, Italy. RP Norby, P (reprint author), Univ Oslo, Dept Chem, POB 1033, N-0315 Oslo, Norway. RI Vaughan, Gavin/B-1479-2010; Hanson, jonathan/E-3517-2010; Gualtieri, Alessandro/L-9680-2015; Norby, Poul/B-9047-2014 OI Gualtieri, Alessandro/0000-0002-4414-9603; Norby, Poul/0000-0002-2590-7050 NR 25 TC 11 Z9 11 U1 0 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD MAY PY 2000 VL 12 IS 5 BP 1473 EP 1479 DI 10.1021/cm991210h PG 7 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 315WW UT WOS:000087136800041 ER PT J AU Burger, D Neumuller, R Yang, GL Engelhardt, H Quinones, I Guiochon, G AF Burger, D Neumuller, R Yang, GL Engelhardt, H Quinones, I Guiochon, G TI Determination and comparison of competitive isotherms by frontal analysis and frontal velocity analysis SO CHROMATOGRAPHIA LA English DT Article DE column liquid chromatography; competitive isotherm measurement; mass balance; frontal velocity analysis; enantiomeric separation ID CHROMATOGRAPHIC BAND PROFILES; ADSORPTION-ISOTHERMS; LIQUID-CHROMATOGRAPHY; STATIONARY PHASES; ENANTIOMERS; SEPARATIONS; BINARY; RATES AB The competitive isotherms of the two enantiomers of oxazepam on two chiral stationary phases differing by the surface concentration of the chiral selector were derived from adsorption data measured with only the racemic mixture. Sample solubility problems limited the range of concentrations within which the measurements were possible. Slow racemization of oxazepam at room temperature prevented the use of any other sample composition than that of the racemic mixture. TWO different approaches, the conventional binary frontal analysis method and the new frontal velocity method were applied for the determination of these competitive isotherms. Both sets of experimental data were found to fit well to the competitive-langmuir isotherm equation. The best coefficients obtained with the two methods were close. The frontal velocity method has the advantages of a greater experimental simplicity, of being faster, and of requiring a smaller amount of material to acquire the necessary data. It may suffer, however, from the possibility of a systematic drift of the isotherm data due to cumulative errors. C1 Univ Saarlandes, D-66123 Saarbrucken, Germany. Hebei Univ, Dept Chem, Baoding 071002, Peoples R China. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Engelhardt, H (reprint author), Univ Saarlandes, Stadtwald, D-66123 Saarbrucken, Germany. NR 27 TC 7 Z9 7 U1 0 U2 1 PU VIEWEG PI WIESBADEN PA ABRAHAM-LINCOLN-STRABE 46, POSTFACH 15 47, D-65005 WIESBADEN, GERMANY SN 0009-5893 J9 CHROMATOGRAPHIA JI Chromatographia PD MAY PY 2000 VL 51 IS 9-10 BP 517 EP 525 DI 10.1007/BF02490807 PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 324KU UT WOS:000087621500001 ER PT J AU Wehner, MF AF Wehner, MF TI A method to aid in the determination of the sampling size of AGCM ensemble simulations SO CLIMATE DYNAMICS LA English DT Article ID MODEL INTERCOMPARISON PROJECT; GENERAL-CIRCULATION MODEL; SEASONAL PREDICTABILITY; AMIP; VARIABILITY AB Historically, the high computational expense of performing lengthy climate simulations has limited the number of possible realizations. Here, we exploit the computational advantage of a recently developed parallel atmospheric general circulation model (AGCM) to determine the number of realizations required to calculate the model's statistics to a specified degree of certainty. Using standard statistical analysis techniques, this minimum ensemble size is found to be highly dependent on which output field is under examination. A strong dependence on location, season and averaging is also revealed. We present a methodology to assess requirements on ensemble size for a certain class of experiments. This technique relies upon estimations of the climate model's internal noise characteristics and the desired level of certainty in the model's output. In Sect. 2, some current applications of ensemble climate simulations are discussed. The experimental design for this study is presented in Sect. 3. Section 4 introduces the details of our technique to estimate minimum ensemble size. In Sect. 5, results are obtained from the numerical experiment under a variety of different conditions for several variables. Some applications and limitations of this method are discussed in Sect. 6. Finally, a discussion on the normality of climate model statistics is presented in the Appendix. C1 Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94551 USA. RP Wehner, MF (reprint author), Univ Calif Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94551 USA. NR 25 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD MAY PY 2000 VL 16 IS 5 BP 321 EP 331 DI 10.1007/s003820050331 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 321JM UT WOS:000087452400001 ER PT J AU Den Auwer, C Simoni, E Conradson, SD de Leon, JM Moisy, P Beres, A AF Den Auwer, C Simoni, E Conradson, SD de Leon, JM Moisy, P Beres, A TI X-ray absorption L-III and M-V edges of hexavalent lower actinides SO COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE II FASCICULE C-CHIMIE LA English DT Article DE XANES; uranium; neptunium; plutonium; perovskite ID FINE-STRUCTURE SPECTROSCOPY; MULTIPLE-SCATTERING; ELECTRONIC-STRUCTURE; COMPLEXES; AQUO; GLASS; IONS AB X-ray absorption spectroscopy is used to probe the electronic and structural features of the actinides. To better understand the effect of the effective charge and polyhedron on the edge structure, we discuss the L-m and M-v edges in AnO(2)(NO3)(2)(TBP)(2) (where the actinide is shortly linked to the 'yl' oxygens) and in the perovskite Ba(2)ZnAnO(6) (where the hexavalent actinide is in the cubic structure as An(6+)), An = U, Np, Pu. Using FEFF8 simulations, both features and position of the L-m and M-v edges are explained within a crystal field splitting of the orbitals picture and a multiple scattering picture. (C) 2000 Academic des sciences / Editions scientifiques et medicales Elsevier SAS. C1 CEA Marcoule, SEMP, DRRV, DCC,Lab Chim Theor & Struct, F-30207 Bagnols Sur Ceze, France. Inst Phys Nucl Orsay, F-91494 Orsay, France. Univ Calif Los Alamos Natl Lab, Div Mat Sci & Technol, Los Alamos, NM 87545 USA. CINVESTAV, Dept Fis Aplicada, Merida, Mexico. CEA Marcoule, SEMP, DRRV, DCC,Lab Chim Appl Analyt, F-30207 Bagnols Sur Ceze, France. RP Den Auwer, C (reprint author), CEA Marcoule, SEMP, DRRV, DCC,Lab Chim Theor & Struct, F-30207 Bagnols Sur Ceze, France. RI Moisy, Philippe/H-2477-2015 OI Moisy, Philippe/0000-0002-9331-0846 NR 29 TC 13 Z9 13 U1 2 U2 17 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 1387-1609 J9 CR ACAD SCI II C JI Comptes Rendus Acad. Sci. Ser. II C PD MAY PY 2000 VL 3 IS 5 BP 327 EP 333 DI 10.1016/S1387-1609(00)01150-6 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 353MZ UT WOS:000089280200001 ER PT J AU Creutz, M AF Creutz, M TI Lattice fields and extra dimensions SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computational Physics CCP 99 held in Conjunction with the Centennial Meeting of the American-Physical-Society CY MAR 20-26, 1999 CL ATLANTA, GA SP Amer Phys Soc DE lattice gauge theory; domain-wall fermions ID FORMULATION; FERMIONS; MODEL AB dLattice gauge theory is now well into its third decade as a major subfield of theoretical particle physics. I open these lattice sessions with a brief review of the motivations for this formulation of quantum field theory. I then comment on the recent drive of lattice theorists to include a fictitious "fifth" dimension to treat issues of chiral symmetry and anomalies. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. EM creutz@bnl.gov NR 13 TC 1 Z9 1 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 EI 1879-2944 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAY PY 2000 VL 127 IS 1 BP 37 EP 42 DI 10.1016/S0010-4655(00)00017-5 PG 6 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 313PU UT WOS:000087008700008 ER PT J AU Vu, HX Sanbonmatsu, KY Bezzerides, B DuBois, DF AF Vu, HX Sanbonmatsu, KY Bezzerides, B DuBois, DF TI Laying a foundation for laser-plasma modeling for the national ignition facility SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computational Physics CCP 99 held in Conjuction with the Centennial Meeting of the American-Physical-Society CY MAR 20-26, 1999 CL ATLANTA, GEORGIA SP Amer Phys Soc DE massively parallel; fully kinetic; reduced-description; two-dimensional; particle-in-cell; parametric instabilities; stimulated Brillouin scattering; stimulated Raman scattering; Langmuir decay instability ID DRIVEN PARAMETRIC-INSTABILITIES; STIMULATED SCATTERING PROCESSES; STRONG LANGMUIR TURBULENCE; REDUCED-DESCRIPTION; IRRADIATED PLASMAS; VLASOV SIMULATION; PARTICLE; CODE; COLLAPSE; WAVES AB Three multi-dimensional plasma simulation models for simulating parametric instabilities occurring in laser-produced plasmas are presented. These models are based on a common framework, henceforth referred to as reduced-description, in which the electromagnetic field is represented by three separate temporal envelopes in order to model parametric instabilities with high-frequency and low-frequency daughter waves. Because the temporal envelope representation is used, the explicit dependence on the laser time scale is removed from the simulations models. The time step of the simulation is then restricted by either the electron timescale or the ion timescale, depending on whether parametric instabilities that result in high-frequency daughter waves are important. These simulation models are the basic building blocks of a comprehensive, ongoing model development program at Los Alamos National Laboratory, and have been implemented in multi-dimension on the Accelerated Strategic Computing Initiative (ASCI) parallel computer. Test simulations of stimulated Raman scattering (SRS), stimulated Brillouin scattering (SBS), the Langmuir decay instability (LDI), and the interaction thereof, are presented. (C) 2000 Published by Elsevier Science B.V. Ali rights reserved. C1 Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Div Theory, Los Alamos, NM 87545 USA. RP Vu, HX (reprint author), Univ Calif Los Alamos Natl Lab, Appl Theoret & Computat Div, POB 1663, Los Alamos, NM 87545 USA. NR 20 TC 4 Z9 4 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 MAY PY 2000 VL 127 IS 1 BP 71 EP 90 DI 10.1016/S0010-4655(00)00117-X PG 20 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 313PU UT WOS:000087008700012 ER PT J AU Berman, GP Doolen, GD Tsifrinovich, VI AF Berman, GP Doolen, GD Tsifrinovich, VI TI Quantum computation as a dynamical process SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computational Physics CCP 99 held in Conjuction with the Centennial Meeting of the American-Physical-Society CY MAR 20-26, 1999 CL ATLANTA, GEORGIA SP Amer Phys Soc ID CONTROL-NOT GATE; MAGNETIC-RESONANCE; COMPUTER; ENSEMBLE AB We discuss the dynamical issues of quantum computation. We demonstrate that fast wave function oscillations can affect the performance of Shor's quantum algorithm by destroying the required quantum interference. We also show that this destructive effect can be routinely avoided by using resonant-pulse techniques. We discuss the dynamics of resonant pulse implementations of quantum logic gates in Ising spin systems. We also discuss the influence of non-resonant excitations. We calculate the range of parameters where undesirable non-resonant effects can be minimized. Finally, we describe the "2 pi k-method" which avoids the detrimental deflection of non-resonant qubits, (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, CNLS, Los Alamos, NM 87545 USA. Polytech Univ, Metrotech Ctr 6, IDS Dept, Brooklyn, NY 11201 USA. RP Berman, GP (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 24 TC 1 Z9 1 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 MAY PY 2000 VL 127 IS 1 BP 91 EP 99 DI 10.1016/S0010-4655(00)00031-X PG 9 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 313PU UT WOS:000087008700013 ER PT J AU Guerrero, M Ortiz, G Gubernatis, JE AF Guerrero, M Ortiz, G Gubernatis, JE TI Search for superconductivity in the two-dimensional Hubbard model using the Constrained Path Monte Carlo SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT International Conference on Computational Physics CCP 99 held in Conjuction with the Centennial Meeting of the American-Physical-Society CY MAR 20-26, 1999 CL ATLANTA, GEORGIA SP Amer Phys Soc ID FERMION GROUND-STATES; SYSTEMS AB The search for a superconducting state in the two-dimensional one-band Hubbard model (HM) has been intense in the last few years. Monte Carlo methods, haunted by the infamous fermion sign problem, have been unable to study large enough systems and low enough temperatures. The Constrained Path Monte Carlo method (CPMC) evades the sign problem by introducing an approximate constraining state. We introduce a new formulation of the CPMC that allows the implementation of a whole family of generalized mean-field states as constraint, and calculate superconducting pairing correlation functions in the HM for lattices up to 12 x 12. We compare the results obtained using a BCS and a free-electron constraining wave-function. We find that the d-wave correlations are insensitive to the constraining state used. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP Guerrero, M (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. NR 10 TC 0 Z9 0 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 MAY PY 2000 VL 127 IS 1 BP 143 EP 149 DI 10.1016/S0010-4655(00)00024-2 PG 7 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 313PU UT WOS:000087008700021 ER PT J AU Crivelli, S Byrd, R Eskow, E Schnabe, R Yu, R Philip, TM Head-Gordon, T AF Crivelli, S Byrd, R Eskow, E Schnabe, R Yu, R Philip, TM Head-Gordon, T TI A global optimization strategy for predicting alpha-helical protein tertiary structure SO COMPUTERS & CHEMISTRY LA English DT Article; Proceedings Paper CT 5th Conference on Computers in Chemistry/Workshop on New Trends in Computational Methods for Large Molecular Systems CY JUL 01-06, 1999 CL SZKLARSKA, POLAND SP Polish Amer Sklodowska Curie Fdn DE conformational search; constraint optimization; parallelization; hydrophobic effect; energy functions ID HYDROPHOBIC AMINO-ACID; SECONDARY-STRUCTURE; NEURAL NETWORKS; MOLECULAR-DYNAMICS; HYDRATION FORCES; FREE-ENERGY; THERMODYNAMICS; SEQUENCE; BINDING; MODELS AB We present a global optimization strategy that incorporates predicted restraints in both a local optimization context and as directives for global optimization approaches, to predict protein tertiary structure for cc-helical proteins. Specifically, neural networks are used to predict the secondary structure of a protein, restraints are defined as manifestations of the network with a predicted secondary structure and the secondary structure is formed using local minimizations on a protein energy surface, in the presence of the restraints. Those residues predicted to be coil, by the network, define a conformational sub-space that is subject to optimization using a global approach known as stochastic perturbation that has been found to be effective for Lennard-Jones clusters and homo-polypeptides. Our energy surface is an all-atom 'gas phase' molecular mechanics force field, that is combined with a new solvation energy function that penalizes hydrophobic group exposure. This energy function gives the crystal structure of four different cc-helical proteins as the lowest energy structure relative to other conformations, with correct secondary structure but incorrect tertiary structure. We demonstrate this global optimization strategy by determining the tertiary structure of the A-chain of the cc-helical protein, uteroglobin and of a four-helix bundle, DNA binding protein. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Life Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, NERSC Div, Berkeley, CA 94720 USA. Univ Colorado, Dept Comp Sci, Boulder, CO 80309 USA. RP Head-Gordon, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. EM tlhead-gordon@lbl.gov RI Head-Gordon, Teresa/E-5818-2011 NR 44 TC 12 Z9 13 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0097-8485 J9 COMPUT CHEM JI Comput. Chem. PD MAY PY 2000 VL 24 IS 3-4 BP 489 EP 497 DI 10.1016/S0097-8485(99)00087-X PG 9 WC Chemistry, Multidisciplinary; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 311EG UT WOS:000086871300026 PM 10816018 ER PT J AU Bassetti, F AF Bassetti, F TI A lower bound for quantifying overlap effects: An empirical approach SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article DE performance evaluation; instruction overlapping; benchmarking AB Among the many features that are implemented in today's microprocessors there are some that have the capability of reducing the execution time via overlapping of different operations. Overlapping of instructions with other instructions, and overlapping of computation with memory activities are the main way in which execution time is reduced. In this paper we will introduce a notion of overlap and its definition, and a few different ways to capture its effects. We will characterize some of the ASCI benchmarks using the overlap and some other quantities related to it. Also, we will present a characterization of the overlap effects using a lower bound derived empirically from measured data. We will conclude by using the lower bound to estimate other components of the overall execution time. Published by Elsevier Science Ltd. C1 Univ Calif Los Alamos Natl Lab, Sci Comp Grp, Los Alamos, NM 87545 USA. RP Bassetti, F (reprint author), Univ Calif Los Alamos Natl Lab, Sci Comp Grp, Mail Stop B287, Los Alamos, NM 87545 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PD MAY-JUL PY 2000 VL 26 IS 3-4 BP 231 EP 244 DI 10.1016/S0045-7906(99)00044-0 PG 14 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 314MM UT WOS:000087059900005 ER PT J AU Hoffmann, MM Fulton, JL AF Hoffmann, MM Fulton, JL TI Corrosion of nickel metal by hydrothermal sodium tungstate solution observed by in-situ infrared spectroscopy SO CORROSION LA English DT Article DE infrared spectroscopy; nickel; pH; pressure; scanning electron microscopy AB Corrosion of nickel metal in a high-temperature aqueous tungstate solution was described. The corrosion altered the solution's pH, which affected the equilibrium of the solution chemistry. These secondary effects of the corrosion process were observed with in-situ infrared (IR) spectroscopy, demonstrating that important information on corrosion phenomena at the solid-fluid interface may be obtained from in-situ spectroscopic studies of the fluid phase. Subsequent scanning electron microscopy (SEM) analysis of the corroded nickel metal and solid corrosion products support conclusions drawn from solution chemistry measurements. The presented findings are of interest to researchers and engineers that use pure nickel or nickel-bearing alloys as a material for high-temperature, high-pressure applications in aqueous solutions. C1 Pacific NW Natl Lab, Environm & Hlth Sci Div, Richland, WA 99352 USA. RP Hoffmann, MM (reprint author), Pacific NW Natl Lab, Environm & Hlth Sci Div, 902 Battelle Blvd,MS P8-19, Richland, WA 99352 USA. NR 9 TC 0 Z9 0 U1 1 U2 1 PU NATL ASSN CORROSION ENG PI HOUSTON PA 1440 SOUTH CREEK DRIVE, HOUSTON, TX 77084-4906 USA SN 0010-9312 J9 CORROSION JI Corrosion PD MAY PY 2000 VL 56 IS 5 BP 501 EP 504 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 565DK UT WOS:000176353300006 ER PT J AU Mazur, P Katkov, II Katkova, N Critser, JK AF Mazur, P Katkov, II Katkova, N Critser, JK TI The enhancement of the ability of mouse sperm to survive freezing and thawing by the use of high concentrations of glycerol and the presence of an Escherichia coli membrane preparation (Oxyrase) to lower the oxygen concentration SO CRYOBIOLOGY LA English DT Article; Proceedings Paper CT 35th Annual Meeting of the Society-for-Cryobiology CY JUL 12-16, 1998 CL PITTSBURGH, PENNSYLVANIA SP Soc Cryobiol ID CRYOPRESERVED SPERMATOZOA; COOLING RATE; CRYOPROTECTIVE AGENTS; ACROSOMAL INTEGRITY; LIPID-PEROXIDATION; MURINE SPERMATOZOA; OSMOTIC TOLERANCE; WARMING RATE; BULL SPERM; LIVE MICE AB The cryobiological preservation of mouse spermatozoa has presented difficulties in the form of poor motilities or irreproductibility. We have hypothesized several underlying problems. One is that published studies have used concentrations of the cryoprotectant glycerol that are substantially lower (<0.3 M) than the similar to 1 M concentrations that are optimal for most mammalian cells. Another may arise from the known high susceptibility of mouse sperm to free radical damage. We have been able to obtain high motilities in 0.8 M glycerol provided that the exposure time is held to similar to 5 min to minimize toxicity and provided that the glycerol is added and removed stepwise to minimize osmotic shock. Since free radical damage in mouse sperm is proportional to the oxygen concentrations, we have determined the consequences of reducing the oxygen to <3% of atmospheric by maintaining the sperm in contact with an Escherichia coli membrane preparation, Oxyrase, from the moment of collection throughout the assessment of motility. Prior studies have shown that the procedure significantly reduces damage from centrifugation and osmotic shock. In the experiments reported here we obtained similar to 50% motility relative to untreated controls when suspensions containing 3.8% Oxyrase were exposed similar to 5 min to a solution of 0.8 M glycerol and 0.17 M (10%) raffinose in a supplemented WS and then frozen at similar to 25 degrees C/min to -75 degrees C. In the absence of Oxyrase, the normalized motility dropped to 31%. The protection by Oxyrase was in part a consequence of minimizing centrifugation damage, burin part it reflected a reduction in freeze-thaw damage. Preliminary experiments indicate that the number of motile sperm after cryopreservation in Oxyrase is higher when the sperm are collected without swim-up than when they are collected by swim-up. This is in part due to the fact that more cells are collected in the absence of swim-up and in part due to a greater protective effect of Oxyrase on those cells. The minimum temperature in these initial experiments was limited to -75 degrees C to avoid the potential contribution of other injurious factors between -75 and - 196 degrees C. (C) 2000 Academic Press. C1 Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN USA. Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Fundamental & Appl Cryobiol Grp, Knoxville, TN 37392 USA. Indiana Univ, Sch Med, Cryobiol Res Inst, Indianapolis, IN USA. RP Mazur, P (reprint author), Univ Tennessee, Dept Biochem & Cellular & Mol Biol, Fundamental & Appl Cryobiol Grp, Knoxville, TN 37392 USA. RI Katkov, Igor/D-7163-2015 OI Katkov, Igor/0000-0001-9251-0494 FU NCRR NIH HHS [7R24- RR13194]; NICHD NIH HHS [R01-HD30274] NR 51 TC 44 Z9 45 U1 0 U2 7 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0011-2240 J9 CRYOBIOLOGY JI Cryobiology PD MAY PY 2000 VL 40 IS 3 BP 187 EP 209 DI 10.1006/cryo.2000.2238 PG 23 WC Biology; Physiology SC Life Sciences & Biomedicine - Other Topics; Physiology GA 322QN UT WOS:000087520400001 PM 10860619 ER PT J AU Gaiser, EE Johansen, J AF Gaiser, EE Johansen, J TI Freshwater diatoms from Carolina bays and other isolated wetlands on the Atlantic Coastal Plain of South Carolina, USA, with descriptions of seven taxa new to science SO DIATOM RESEARCH LA English DT Article ID WATER CHEMISTRY; ASSEMBLAGES; LAKE; BACILLARIOPHYCEAE; PHYTOPLANKTON; PERIODICITY; PONDS AB This study represents the first taxonomic and ecological description of the diatom flora of Carolina bays, the most abundant, natural lentic systems on the Atlantic Coastal Plain of the United States. Diatoms were collected from surface sediments and benthic and planktonic microhabitats in Carolina bays and other isolated wetland ponds in South Carolina during three seasons to survey the extant flora and document habitat affinities. The ponds ranged from marshes and grass/sedge meadows to forested swamps and were prone to episodic drying. All were acidic, dystrophic and nutrient-poor. At the generic level, diatom assemblages resembled those of other acidic, shallow ponds, being dominated by Eunotia, Pinnularia, Frustulia and Neidium. Diatom assemblages were distinct from neighboring lotic and reservoir systems, and contained several taxa new to science. Considerable variation in diatom assemblage composition among ponds was attributable, in part, to differences in susceptibility of the ponds to drying. In basins that dry frequently, aerophilic taxa such as Orthoseira dendroteres (Ehrenberg) Crawford, Pinnularia borealis var. scalaris (Ehrenberg) Rabhenhorst and Luticola saxophila (Bock ex Hustedt) Mann were common. Permanent pond assemblages were dominated by species of Frustulia, Tabellaria and Stenopterobia. Habitat fidelity was low; most taxa were associated with a diversity of substrates and did not exhibit marked seasonality. Substrate and seasonal associations are given for taxa with notable affinities. Taxonomic descriptions are provided for Eunotia pocosinensis sp. nov., Eunotia sarraceniae sp. nov., Stauroneis anceps var. subrostrata var, nov., Pinnularia turfosiphila sp. nov., Pinnularia bigibba sp. nov., Pinnularia subgibba var. gracilis var. nov. and Pinnularia subgibba var. lanceolata var. nov. C1 Univ Georgia, Savannah River Ecol Lab, PO Drawer E, Aiken, SC 29802 USA. John Carroll Univ, Dept Biol, Cleveland, OH 44118 USA. RP Gaiser, EE (reprint author), Florida Int Univ, SE Environ Res Program, Miami, FL 33199 USA. RI Johansen, Jeff/F-5616-2011 NR 75 TC 45 Z9 49 U1 3 U2 11 PU BIOPRESS LIMITED PI BRISTOL PA THE ORCHARD, CLANAGE RD, BRISTOL BS3 2JX, ENGLAND SN 0269-249X J9 DIATOM RES JI Diatom Res. PD MAY PY 2000 VL 15 IS 1 BP 75 EP 130 PG 56 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 344KB UT WOS:000088756800006 ER PT J AU Melchiorre, EB Criss, RE Rose, TP AF Melchiorre, EB Criss, RE Rose, TP TI Oxygen and carbon isotope study of natural and synthetic azurite SO ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS LA English DT Article ID PHOSPHORIC-ACID; FRACTIONATION; MALACHITE; HYDROGEN AB Slow precipitation experiments were used to determine the oxygen isotope fractionation between azurite((CO3)), and water. This temperature-dependent fractionation is 1000 ln alpha = 2.67 (10(6)/T-2) + 4.75, where T is in kelvins, azurite((CO3)) denotes the CO2 liberated by acidification of azurite and corrected to calcite standards. Oxygen isotope data for 46 azurite samples from 44 localities around the world suggest formation from meteoric waters. Both carbon and oxygen isotope delta values for natural azurites are consistent with values recorded for speleothems, soil carbonates, and malachite, suggesting that azurite commonly derives much of its carbon from isotopically light soil CO2. The new oxygen isotope thermometer indicates that most natural azurites form within +/-10 degrees C of modern local air temperatures. A few azurite samples from deposits of massive sulfides yield apparent temperatures up to 48 degrees C, which are significantly higher than modem air temperatures. We suggest that the higher apparent temperatures record the heat produced during oxidation of concentrated sulfides. Our results indicate that exothermic oxidation of massive sulfide deposits can produce shallow subsurface temperatures up to 25 degrees C higher than mean local air temperatures. C1 Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Univ Calif Lawrence Livermore Natl Lab, Isotope Sci Div, Livermore, CA 94550 USA. RP Melchiorre, EB (reprint author), Depauw Univ, Dept Geol & Geog, Greencastle, IN 46135 USA. NR 38 TC 11 Z9 11 U1 0 U2 7 PU ECONOMIC GEOLOGY PUBL CO PI LITTLETON PA 5808 SOUTH RAPP ST, STE 209, LITTLETON, CO 80120-1942 USA SN 0361-0128 J9 ECON GEOL BULL SOC JI Econ. Geol. Bull. Soc. Econ. Geol. PD MAY PY 2000 VL 95 IS 3 BP 621 EP 628 DI 10.2113/95.3.621 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 318EB UT WOS:000087270000011 ER PT J AU Seshadri, KS Smith, DH AF Seshadri, KS Smith, DH TI Compositions of filter-vessel and cyclone "ash" from pressurized fluidized bed combustion SO ENERGY & FUELS LA English DT Article ID PFBC AB Excessively hard filter cakes have occurred during filtration of fine particles from hot gases in pressurized fluidized bed combustion (PFBC) power plants in which dolomitic limestone was used as the SOx sorbent. These deposits forced premature plant shutdown and became a major barrier to successful development of the filtration technology. Our previous work implicated Mg2Ca(SO4)(3) as a chief cause of these excessive cake strengths, but no analytical technique was available to quantitatively relate filter-cake physical properties and operating problems to Mg2Ca(SO4)(3) concentrations. Hence, a new Fourier transform infrared spectroscopy technique has been developed to analyze for Mg2Ca(SO4)(3) in the presence of CaSO4 and other compounds in PFBC samples. This technique was used to measure chemical compositions of various samples taken from either the cyclone or the hot-gas filtration vessel of a PFBC demonstration power plant. These measurements clarify and further demonstrate the critical role played by Mg2Ca(SO4)(3). Further measurements of the type described here should allow researchers to quantitatively determine how Mg2Ca(SO4)(3) concentrations in filter cakes depend on various operating parameters (e.g., temperatures, pressures, and composition of the coal and sorbent), and thus solve problems that have prevented the successful development of hot-gas filtration for PFBC power plants. C1 US DOE, Natl Energy Technol Lab, Morgantown, WV 26507 USA. Parsons Infrastruct & Technol Grp, Morgantown, WV 26505 USA. W Virginia Univ, Dept Phys, Morgantown, WV 26506 USA. RP Smith, DH (reprint author), US DOE, Natl Energy Technol Lab, Morgantown, WV 26507 USA. NR 24 TC 3 Z9 3 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0887-0624 J9 ENERG FUEL JI Energy Fuels PD MAY-JUN PY 2000 VL 14 IS 3 BP 526 EP 532 DI 10.1021/ef9900482 PG 7 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 315YD UT WOS:000087139800002 ER PT J AU Boyd, GA Pang, JX AF Boyd, GA Pang, JX TI Estimating the linkage between energy efficiency and productivity SO ENERGY POLICY LA English DT Article DE productivity; energy efficiency; frontier production function; learning by doing AB Many analyses have referred to industrial productivity benefits associated with energy efficiency that are at least as great or larger than the energy benefits. If plants with higher energy intensity also tend to have lower productivity, then energy policy needs to consider this. This study examines this issue for two segments of the glass industry, using plant level data from the Census Bureau. Productivity is defined by the difference in 'best practice' production efficiency, as measured by data envelopment analysis (DEA). This study uses regression analysis to estimate how differences in plant level electricity and fossil fuel intensity, i.e. energy use per unit of production, are attributable to differences in plant level productivity and other economic variables, like energy prices and cumulative production. In every case, productivity differences between plants are statistically significant in explaining differences in plant energy intensity. The coefficient that links productivity to energy efficiency yields a less than proportional impact for only one industry and fuel type. For others the relationship is implies that a 1% increase in productivity increase energy efficiency by more than 1%. This effect is statistically significant for flat glass, but not container glass. The estimates of the price and learning-by-doing coefficients seem reasonable, but without imposing the assumption that all plants in the industry are equally productive. This lends further credence to a significant relationship between productivity and energy efficiency. (C) 2000 Elsevier Science Ltd. All rights reserved. JEL classification: L61; O30; Q20. C1 Argonne Natl Lab, Policy & Econ Anal Grp, Argonne, IL 60439 USA. Univ Chicago, Dept Econ, Chicago, IL 60637 USA. RP Boyd, GA (reprint author), Argonne Natl Lab, Policy & Econ Anal Grp, DIS-900 Rm,1-14,9700 C Cass Ave, Argonne, IL 60439 USA. NR 10 TC 110 Z9 123 U1 7 U2 22 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0301-4215 J9 ENERG POLICY JI Energy Policy PD MAY PY 2000 VL 28 IS 5 BP 289 EP 296 DI 10.1016/S0301-4215(00)00016-1 PG 8 WC Energy & Fuels; Environmental Sciences; Environmental Studies SC Energy & Fuels; Environmental Sciences & Ecology GA 307LK UT WOS:000086654600001 ER PT J AU Bull, RJ AF Bull, RJ TI Mode of action of liver tumor induction by trichloroethylene and its metabolites, trichloroacetate and dichloroacetate SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Review DE chloral hydrate; dichloroacetate; liver tumors; mode of action; trichloroacetate; trichloroethylene ID FEMALE B6C3F1 MICE; UNSCHEDULED DNA-SYNTHESIS; RETINOID-X RECEPTOR; RENAL-CELL CANCER; CHLORAL HYDRATE; MOUSE-LIVER; SPECIES-DIFFERENCES; STRAND BREAKS; IN-VIVO; PEROXISOME PROLIFERATION AB Trichloroethylene (TCE) induces liver cancer in mice but not in rats. Three metabolites of TCE may contribute-chloral hydrate (CH), dichloroacetate (DCA), and trichloroacetate (TCA). Ctl and TCA appear capable of only inducing liver tumors in mice, but DCA is active in rats as well. The concentrations of TCA in blood required to induce liver cancer approach the mM range. Concentrations of DCA in blood associated with carcinogenesis are in the sub-mu M range. The carcinogenic activity of CH is largely dependent on its conversion to TCA and/or DCA. TCA is a peroxisome proliferator in the same dose range that induces liver cancer. Mice with targeted disruptions of the peroxisome proliferator-activated receptor alpha (PPAR alpha) are insensitive to the liver cancer-inducing properties of other peroxisome proliferators. Human cells do not display the responses associated with PPAR alpha. that are observed in rodents. This may be attributed to lower levels of expressed PPARa in human liver. DCA treatment produces liver tumors with a different phenotype than TCA. Its tumorigenic effects are closely associated with differential effects on cell replication rates in tumors, normal hepatocytes, and suppression of apoptosis. Growth of DCA-induced tumors has been shown to arrest after cessation of treatment. The DCA and TCA adequately account for the hepatocarcinogenic responses to TCE. Low-level exposure to TCE is not likely to induce liver cancer in humans. Higher exposures to TCE could affect sensitive populations. Sensitivity could be based on different metabolic capacities for TCE or its metabolites or result from certain chronic diseases that have a genetic basis. C1 US DOE, Pacific NW Lab, Mol Biosci Dept, Richland, WA 99352 USA. RP Bull, RJ (reprint author), US DOE, Pacific NW Lab, Mol Biosci Dept, POB 999 P7-56, Richland, WA 99352 USA. NR 159 TC 99 Z9 106 U1 0 U2 8 PU US DEPT HEALTH HUMAN SCIENCES PUBLIC HEALTH SCIENCE PI RES TRIANGLE PK PA NATL INST HEALTH, NATL INST ENVIRONMENTAL HEALTH SCIENCES, PO BOX 12233, RES TRIANGLE PK, NC 27709-2233 USA SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD MAY PY 2000 VL 108 SU 2 BP 241 EP 259 PG 19 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 316CC UT WOS:000087149000007 PM 10807555 ER PT J AU Smith, JG Beauchamp, JJ AF Smith, JG Beauchamp, JJ TI Evaluation of caging designs and a fingernail clam for use in an in situ bioassay SO ENVIRONMENTAL MONITORING AND ASSESSMENT LA English DT Article DE biomonitoring; clams; in situ bioassay; sphaeriidae; streams ID CERIODAPHNIA-DUBIA; GAMMARUS-PULEX; RECEIVING STREAMS; WATER-QUALITY; TOXICITY; COMMUNITIES; DISTURBANCE; RECOVERY; INVERTEBRATE; RESPONSES AB Two cage designs and fingernail clams (Sphaerium fabale) were evaluated for their suitability for use in in situ bioassays to assess the ecological condition of a stream and predict ecological recovery potential. One design (referred to as tray design) was a modified plastic tray about one-fourth full of small gravels and covered with 1 mm fiberglass mesh. The second design (referred to as tube-plates) consisted of short plexiglass tubes about one-third full of small gravels and attached horizontally to a plexiglass plate. One end of each tube faced into the current; both ends were covered with mesh. Cages containing clams were deployed at reference and impacted (test) sites for periods of 70 to 135 d. Growth and survival were the primary endpoints evaluated, but the tube-plates allowed isolation of individual clams so that natality also could be evaluated as an endpoint. Results of benthic macroinvertebrate surveys, performed for another study, were included to help validate bioassay results. Both cage designs yielded good quantitative, site-specific results for clam survival and growth; results for natality, though, were less conclusive. Clam survival and growth results were in good general agreement with the results for the benthic macroinvertebrate community surveys. At a site where the macroinvertebrate community was the most depauperate, clam mortality was always rapid. At a site where the condition of the macroinvertebrate community was only slightly less impacted than the most impacted site, clam growth was almost always significantly lower than at reference sites. Survival of clams was significantly reduced in < 25 d at this site in some trials, but in other trials there was little mortality. At a minimally impacted site, clam survival was similar to that found at reference sites, and differences in clam growth were not detectable until after 40 to 50 d of exposure. The tube-plate design was easier to use, allowed more flexibility in selection of response parameters, and required less handling time of test animals, thus, this was the preferred design. Our results demonstrated that either in situ bioassay design can be used to augment monitoring and assessment programs. Their use as a predictor of ecological recovery, however, requires further evaluation. C1 Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Smith, JG (reprint author), Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA. NR 58 TC 9 Z9 10 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-6369 J9 ENVIRON MONIT ASSESS JI Environ. Monit. Assess. PD MAY PY 2000 VL 62 IS 2 BP 205 EP 230 DI 10.1023/A:1006297703131 PG 26 WC Environmental Sciences SC Environmental Sciences & Ecology GA 304ZZ UT WOS:000086515500007 ER PT J AU Porro, I Newman, ME Dunnivant, FM AF Porro, I Newman, ME Dunnivant, FM TI Comparison of latch and column methods for determining strontium distribution coefficients for unsaturated transport in basalt SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID SORBING POROUS-MEDIA; SOLUTE TRANSPORT; MASS-TRANSFER; SORPTION; ISOTHERMS; AQUIFER; SOILS; EQUILIBRIUM; SOLIDS; BATCH AB Contaminant distribution coefficients determined under saturated conditions are often used to model transport under unsaturated conditions. Although the distribution coefficients are assumed to be consistent under different moisture conditions, this is rarely tested. Column and batch adsorption tests were used to determine strontium distribution coefficients in crushed basalt. Column tests were conducted at saturated and unsaturated moisture contents. Batch tests were conducted at several solid/liquid ratios. Preliminary column tests using bromide as a conservative tracer indicated the presence of immobile water in the column and pointed toward the use of a two-region model to determine the Sr distribution coefficients. Use of a single-region model (no immobile water), however, resulted in an average value (3.09 mL/g) not significantly different than the average value determined using the two-region model (3.41 mL/g). Moisture content had no significant effect on Sr distribution coefficients determined by applying either model to the column test data. The batch test distribution coefficient determined at the recommended standard solid/liquid ratio (0.25 g/mL) was less than the column test values and decreased significantly with increasing solid/liquid ratio. The results indicate that K(d)s determined with this method will not accurately reflect Sr transport in unsaturated or saturated basalt. C1 Idaho Natl Engn & Environm Lab, Idaho Falls, ID 83415 USA. RP Porro, I (reprint author), Idaho Natl Engn & Environm Lab, POB 1625, Idaho Falls, ID 83415 USA. NR 43 TC 48 Z9 50 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 1 PY 2000 VL 34 IS 9 BP 1679 EP 1686 DI 10.1021/es9901361 PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 309XL UT WOS:000086794500026 ER PT J AU He, LM Neu, MP Vanderberg, LA AF He, LM Neu, MP Vanderberg, LA TI Bacillus lichenformis gamma-glutamyl exopolymer: Physicochemical characterization and U(VI) interaction SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID GAMMA-POLY(GLUTAMIC ACID) FORMATION; BACTERIAL EXTRACELLULAR POLYMERS; POROUS-MEDIA; POLY(GAMMA-D-GLUTAMYL) CAPSULE; BINDING CHARACTERISTICS; HEAVY-METALS; LICHENIFORMIS; TRANSPORT; BIOSYNTHESIS; CHEMISTRY AB Complexation by microbially produced exopolymers may significantly impact the environmental mobility and toxicity of metals. This study focused on the conformational structure of the bacterial exopolymer, gamma-D-poly(glutamic acid):and its interactions with U(VI) examined using ATR-FTIR spectroscopy. Solution pH, polymer concentration, and ionic strength affected the conformation of the exopolymer, and U(VI) binding was monitored. At low pH, low concentration, or low ionic strength, this exopolymer exists -in an alpha-helical conformation, while at high pH, concentration, or ionic strength the exopolymer exhibits a beta-sheet structure. The change in exopolymer conformation is likely to influence the number and nature of exposed surface functional groups, sites most responsible for metal complexation. We found the polyglutamate capsule binds U(VI) in a binuclear, bidentate fashion; in contrast the glutamate monomer forms a mononuclear, bidentate complex with U(VI). The apparent polynuclear binding of U(VI) may induce beta-sheet structure formation provided the U(VI) concentration is sufficiently high. C1 Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP Neu, MP (reprint author), Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Mail Stop G739, Los Alamos, NM 87545 USA. NR 59 TC 34 Z9 36 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 1 PY 2000 VL 34 IS 9 BP 1694 EP 1701 DI 10.1021/es991119e PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 309XL UT WOS:000086794500028 ER PT J AU Koester, CJ Beller, HR Halden, RU AF Koester, CJ Beller, HR Halden, RU TI Analysis of perchlorate in groundwater by electrospray ionization mass spectrometry/mass spectrometry SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID CHROMATOGRAPHY; OXYHALIDES AB An electrospray ionization mass spectrometry/mass spectrometry (ESI/MS/MS) method was developed to measure part-per-billion (mu g/L) concentrations of perchlorate in groundwater. Selective and sensitive perchlorate detection was achieved by operating the mass spectrometer in the negative ionization mode and by using MS/MS to monitor the ClO4- to ClO3- transition. The method of sta nda rd additions was used to address the considerable signal suppression caused by anions that are typically present in groundwater, such as bicarbonate and sulfate. ESI/MS/MS analysis was rapid, accurate, reproducible, and provided a detection limit of 0.5 mu g/L perchlorate in groundwater. Accuracy and precision of the ESI/MS/MS method were assessed by analyzing performance evaluation samples in a groundwater matrix (4.5-75 mu g/L perchlorate) and by comparing ion chromatography (IC) and ESI/MS/MS results for local groundwater samples (<0.5-35 mu g/L perchlorate). Results for the performance evaluation samples differed from the certified values by 4-13%, and precision ranged from 3 to 10% (relative standard deviation). The IC and ESI/MS/MS results were statistically indistinguishable (P > 0.05) for perchlorate concentrations above the detection limits of both methods. C1 Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Beller, HR (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-542, Livermore, CA 94551 USA. RI Beller, Harry/H-6973-2014; Halden, Rolf/F-9562-2010 OI Halden, Rolf/0000-0001-5232-7361 NR 14 TC 63 Z9 67 U1 1 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 1 PY 2000 VL 34 IS 9 BP 1862 EP 1864 DI 10.1021/es991209j PG 3 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 309XL UT WOS:000086794500051 ER PT J AU Baker, RJ Chesser, RK AF Baker, RJ Chesser, RK TI The Chernobyl nuclear disaster and subsequent creation of a wildlife preserve SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Letter ID THYROID-CANCER; POWER-PLANT; ACCIDENT C1 Texas Tech Univ, Lubbock, TX 79409 USA. Int Radioecol Lab, Slavutych, Ukraine. Savannah River Ecol Lab, Aiken, SC USA. RP Baker, RJ (reprint author), Texas Tech Univ, Lubbock, TX 79409 USA. NR 14 TC 29 Z9 32 U1 2 U2 35 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAY PY 2000 VL 19 IS 5 BP 1231 EP 1232 DI 10.1897/1551-5028(2000)019<1231:TCNDAS>2.3.CO;2 PG 2 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 307DC UT WOS:000086637300001 ER PT J AU Urban, W Schulz, N Bentaleb, M Lubkiewicz, E Durell, JL Leddy, MJ Jones, MA Phillips, WR Smith, AG Varley, BJ Ahmad, I Morss, LR AF Urban, W Schulz, N Bentaleb, M Lubkiewicz, E Durell, JL Leddy, MJ Jones, MA Phillips, WR Smith, AG Varley, BJ Ahmad, I Morss, LR TI Simplex s = +/- i excitations in Xe-141 SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID NEUTRON-RICH; OCTUPOLE CORRELATIONS; BARIUM ISOTOPES; TRANSITION; DEFORMATION; PARITIES; FISSION; NUCLEI AB Excited levels in Xe-141, populated in spontaneous fission of Cm-248, were studied by means of prompt, gamma-ray spectroscopy, using the EUROGAMM2 arras. Level scheme of Xe-141 obtained in this work shows patterns characteristic of simplex symmetry with s = +i and s = -i bands present but low value of D-0 moment indicates that octupole correlations in Xe isotopes are systematically lower than in Ba nuclei. C1 Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. CNRS, IN2P3, UMR 7500, Inst Rech Subatom, F-67037 Strasbourg, France. Univ Strasbourg 1, F-67037 Strasbourg, France. Univ Manchester, Dept Phys & Astron, Schuster Lab, Manchester M13 9PL, Lancs, England. Argonne Natl Lab, Argonne, IL 60439 USA. RP Urban, W (reprint author), Univ Warsaw, Inst Expt Phys, Hoza 69, PL-00681 Warsaw, Poland. NR 10 TC 9 Z9 10 U1 0 U2 1 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD MAY PY 2000 VL 8 IS 1 BP 5 EP 7 DI 10.1007/s100500070113 PG 3 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 338WY UT WOS:000088447300002 ER PT J AU Bender, M Rutz, K Reinhard, PG Maruhn, JA AF Bender, M Rutz, K Reinhard, PG Maruhn, JA TI Pairing gaps from nuclear mean-field models SO EUROPEAN PHYSICAL JOURNAL A LA English DT Article ID GENERATOR-COORDINATE METHOD; PARTICLE NUMBER PROJECTION; DENSITY-DEPENDENT FORCES; SUPERDEFORMED NUCLEI; ISOTOPE SHIFTS; DRIP-LINE; ENERGY; SYMMETRY; SHAPE; RESTORATION AB We discuss the pairing gap, a measure for nuclear pairing correlations, in chains of spherical, semi-magic nuclei in the framework of self-consistent nuclear mean-field models, The equations for the conventional BCS model and the approximate projection-before-variation Lipkin-Nogami method are formulated ill terms of local density functionals for the effective interaction. We calculate the Lipkin-Nogami corrections of both thr mean-field energy and the pairing energy. Various definitions of the pairing gap are discussed as three-point, four-point and five-point mass-difference formulae, averaged matrix elements of the pairing potential, and single-quasiparticle energies. Experimental values for the pairing gay. are compared with calculations employing both a delta pairing force and a density-dependent delta interaction in the BCS and Lipkin-Nogami model. Odd-mass nuclei are calculated in the spherical blocking approximation which neglects part of the the core polarization in the odd nucleus. We find that the five-point mass difference formula gives a very robust description of the odd-even staggering, other approximations for the gap may differ from that up to 30% for certain nuclei. C1 Univ Frankfurt, Inst Theoret Phys, D-60325 Frankfurt, Germany. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27516 USA. Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA. Univ Erlangen Nurnberg, Inst Theoret Phys 2, D-91058 Erlangen, Germany. Oak Ridge Natl Lab, Joint Inst Heavy Ion Res, Oak Ridge, TN 37831 USA. RP Bender, M (reprint author), Univ Frankfurt, Inst Theoret Phys, Robert Mayer Str 10, D-60325 Frankfurt, Germany. RI Bender, Michael/B-9004-2009 NR 60 TC 171 Z9 176 U1 1 U2 11 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6001 J9 EUR PHYS J A JI Eur. Phys. J. A PD MAY PY 2000 VL 8 IS 1 BP 59 EP 75 PG 17 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 338WY UT WOS:000088447300008 ER PT J AU Rasmussen, KO Aubry, S Bishop, AR Tsironis, GP AF Rasmussen, KO Aubry, S Bishop, AR Tsironis, GP TI Discrete nonlinear Schrodinger breathers in a phonon bath SO EUROPEAN PHYSICAL JOURNAL B LA English DT Article ID INTRINSIC LOCALIZED EXCITATIONS; LATTICES; ENERGY; EQUATION; RELAXATION; EXISTENCE; MOBILITY AB We study the dynamics of the discrete nonlinear Schrodinger lattice initialized such that a very lung transitory period of time in which standard Boltzmann statistics is insufficient is reached. Our study of the nonlinear system locked in this non-Gibbsian state focuses on the dynamics of discrete breathers (also called intrinsic localized modes). It is found that part of the energy spontaneously condenses into several discrete breathers. Although these discrete breathers are extremely long lived, their total number is found to decrease as the evolution progresses. Even though the total number of discrete breathers decreases we report the surprising observation that the energy content in the discrete breather population increases. We interpret these observations in the perspective of discrete breather creation and annihilation and find that the death of a discrete breather cause effective energy transfer to a spatially nearby discrete breather. It is found that the concepts of a multi-frequency discrete breather and of internal modes is crucial for this process. Finally, we find that the existence of a discrete breather tends to soften the lattice in its immediate neighborhood, resulting in high amplitude thermal fluctuation close to an existing discrete breather. This in turn nucleates discrete breather creation close to a already existing discrete breather. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Los Alamos Natl Lab, Ctr Nonlinear Studies, Los Alamos, NM 87545 USA. CEA, CNRS, Lab Leon Brillouin, F-91191 Gif Sur Yvette, France. Univ Crete, Dept Phys, Iraklion 71003, Crete, Greece. Fdn Res & Technol Hellas, FORTH, Iraklion 71003, Crete, Greece. RP Rasmussen, KO (reprint author), Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. EM kor@lanl.gov RI Rasmussen, Kim/B-5464-2009; Tsironis, George/C-2683-2011; Aubry, Serge/E-9379-2012 OI Rasmussen, Kim/0000-0002-4029-4723; NR 26 TC 42 Z9 42 U1 3 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6028 J9 EUR PHYS J B JI Eur. Phys. J. B PD MAY PY 2000 VL 15 IS 1 BP 169 EP 175 DI 10.1007/PL00011032 PG 7 WC Physics, Condensed Matter SC Physics GA 314DP UT WOS:000087040000021 ER PT J AU Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Sacchi, R Sampson, S Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Stopa, P Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB AF Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Hartmann, H Heinloth, K Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Voss, KC Weber, A Wieber, H Bailey, DS Barret, O Brook, NH Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Rodrigues, E Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Liu, W Liu, X Mellado, B Sacchi, R Sampson, S Sciulli, F Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Stopa, P Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Petrucci, MC Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Waugh, R Bohnet, I Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Garfagnini, A Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Goncalo, R Long, KR Miller, DB Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Nagano, K Tokushuku, K Yamada, S Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Garcia, G Glasman, C Gonzalez, O Labarga, L del Peso, J Redondo, I Terron, J Barbi, M Corriveau, F Hanna, DS Ochs, A Padhi, S Riveline, M Stairs, DG Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Bokel, C Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Boogert, S Cooper-Sarkar, AM Devenish, RCE Grosse-Knetter, J Matsushita, T Ruske, O Sutton, MR Walczak, R Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Abe, T Fusayasu, T Umemori, K Yamashita, T Hamatsu, R Hirose, T Inuzuka, M Kitamura, S Nishimura, T Arneodo, M Cartiglia, N Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Butterworth, JM Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB West, BJ Ciborowski, J Ciesielski, R Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Cole, JE Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB CA ZEUS Collaboration TI Measurement of diffractive photoproduction of vector mesons at large momentum transfer at HERA SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID ELASTIC-SCATTERING; LARGE-T; QCD; ELECTROPRODUCTION; J/PSI; RHO(0); PHOTON; ZEUS; SHRINKAGE; HYDROGEN AB Elastic and proton-dissociative photoproduction of rho(0), phi and J/psi vector mesons (gamma p --> Vp, gamma p --> VN, respectively) have been measured in e(+)p interactions at HERA up to -t = 3 GeV2, where t is the four-momentum transfer squared at the photon-vector-meson vertex. The analysis is based on a data sample in which photoproduction reactions were tagged by detection of the scattered positron in a special-purpose calorimeter. This limits the photon virtuality, Q(2), to values less than 0.01 GeV2, and selects a gamma p average center-of-mass energy of (W) = 94 GeV. Results for the differential cross sections, d sigma/dt, for rho(0), phi and J/psi mesons are presented and compared to the results of recent QCD calculations. Results are also presented for the t-dependence of the pion-pair invariant-mass distribution in the rho(0) mass region and of the spin-density matrix elements determined from the decay-angle distributions. The Pomeron trajectory has been derived from measurements of the W dependence of the elastic differential cross sections d sigma/dt for both rho(0) and phi mesons. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Ist Nazl Fis Nucl, I-87036 Cosenza, Italy. Chonnam Natl Univ, Kwangju, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, Deutsch Elektronen Synchrotron, Hamburg, Germany. DESY, Zeuthen, Germany. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Nazl Frascati Lab, I-00044 Frascati, Italy. Univ Freiburg, Fak Phys, D-7800 Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Exp Phys 1, Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum, Inst Kernphys, Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow Engn Phys Inst, Moscow 115409, Russia. Moscow MV Lomonosov State Univ, Inst Nucl Phys, Moscow, Russia. NIKHEF, Amsterdam, Netherlands. Univ Amsterdam, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford, England. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Ist Nazl Fis Nucl, I-00185 Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-5900 Siegen, Germany. Tel Aviv Univ, Sch Phys, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Fac Sci 2, Alessandria, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Warsaw Univ, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. York Univ, Dept Phys, Toronto, ON M3J 2R7, Canada. IROE, Florence, Italy. Univ Hamburg, Hamburg, Germany. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Morandin, Mauro/A-3308-2016; Solomin, Anatoly/C-3072-2016; Bashkirov, Vladimir/A-4818-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; dusini, stefano/J-3686-2012; Goncalo, Ricardo/M-3153-2016; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; OI De Pasquale, Salvatore/0000-0001-9236-0748; Morandin, Mauro/0000-0003-4708-4240; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; Gladilin, Leonid/0000-0001-9422-8636; dusini, stefano/0000-0002-1128-0664; Goncalo, Ricardo/0000-0002-3826-3442; Graciani Diaz, Ricardo/0000-0001-7166-5198; Kasemann, Matthias/0000-0002-0429-2448; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; Arneodo, Michele/0000-0002-7790-7132; Abbiendi, Giovanni/0000-0003-4499-7562 NR 66 TC 73 Z9 73 U1 1 U2 4 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD MAY PY 2000 VL 14 IS 2 BP 213 EP 238 DI 10.1007/s100520000374 PG 26 WC Physics, Particles & Fields SC Physics GA 329AE UT WOS:000087883300003 ER PT J AU Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Eckert, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Pfeiffer, M Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Weber, A Wieber, H Bailey, DS Barret, O Cottingham, WN Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Cartiglia, N Jing, Z Liu, W Mellado, B Parsons, JA Ritz, S Sacchi, R Sampson, S Sciulli, F Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Dulinski, Z Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milewski, J Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Schwarzer, O Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Burow, BD Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Monig, K Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Brook, NH Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Strickland, E Waugh, R Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Bacon, TC Cole, JE Howell, G Lamberti, L Long, KR Miller, DB Prinias, A Sedgbeer, JK Sideris, D Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Suzuki, I Tokushuku, K Yamada, S Yamauchi, K Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Fernandez, JP Garcia, G Glasman, C Hernandez, JM Labarga, L del Peso, J Puga, J Redondo, I Terron, J Corriveau, F Hanna, DS Hartmann, J Murray, WN Ochs, A Padhi, S Riveline, M Stairs, DG St-Laurent, M Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Blaikley, HE Boogert, S Cashmore, RJ Cooper-Sarkar, AM Devenish, RCE Edmonds, JK Grosse-Knetter, J Harnew, N Matsushita, T Noyes, VA Quadt, A Ruske, O Sutton, MR Walczak, R Waters, DS Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Raso, M Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Schechter, A Abe, T Fusayasu, T Inuzuka, M Nagano, K Umemori, K Yamashita, T Hamatsu, R Hirose, T Homma, K Kitamura, S Nishimura, T Arneodo, M Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Petrucci, MC Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB Ciborowski, J Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB AF Breitweg, J Chekanov, S Derrick, M Krakauer, D Magill, S Musgrave, B Pellegrino, A Repond, J Stanek, R Yoshida, R Mattingly, MCK Abbiendi, G Anselmo, F Antonioli, P Bari, G Basile, M Bellagamba, L Boscherini, D Bruni, A Bruni, G Romeo, GC Castellini, G Cifarelli, L Cindolo, F Contin, A Coppola, N Corradi, M De Pasquale, S Giusti, P Iacobucci, G Laurenti, G Levi, G Margotti, A Massam, T Nania, R Palmonari, F Pesci, A Polini, A Sartorelli, G Garcia, YZ Zichichi, A Amelung, C Bornheim, A Brock, I Coboken, K Crittenden, J Deffner, R Eckert, M Hartmann, H Heinloth, K Heinz, L Hilger, E Jakob, HP Kappes, A Katz, UF Kerger, R Paul, E Pfeiffer, M Rautenberg, J Schnurbusch, H Stifutkin, A Tandler, J Weber, A Wieber, H Bailey, DS Barret, O Cottingham, WN Foster, B Heath, GP Heath, HF McFall, JD Piccioni, D Scott, J Tapper, RJ Capua, M Mastroberardino, A Schioppa, M Susinno, G Jeoung, HY Kim, JY Lee, JH Lim, IT Ma, KJ Pac, MY Caldwell, A Cartiglia, N Jing, Z Liu, W Mellado, B Parsons, JA Ritz, S Sacchi, R Sampson, S Sciulli, F Zhu, Q Borzemski, P Chwastowski, J Eskreys, A Figiel, J Klimek, K Olkiewicz, K Przybycien, MB Zawiejski, L Adamczyk, L Bednarek, B Jelen, K Kisielewska, D Kowal, AM Kowalski, T Przybycien, M Rulikowska-Zarebska, E Suszycki, L Zajac, J Dulinski, Z Kotanski, A Bauerdick, LAT Behrens, U Bienlein, JK Burgard, C Desler, K Drews, G Fox-Murphy, A Fricke, U Goebel, F Gottlicher, P Graciani, R Haas, T Hain, W Hartner, GF Hasell, D Hebbel, K Johnson, KF Kasemann, M Koch, W Kotz, U Kowalski, H Lindemann, L Lohr, B Martinez, M Milewski, J Milite, M Monteiro, T Moritz, M Notz, D Pelucchi, F Piotrzkowski, K Rohde, M Saull, PRB Savin, AA Schneekloth, U Schwarzer, O Selonke, F Sievers, M Stonjek, S Tassi, E Wolf, G Wollmer, U Youngman, C Zeuner, W Burow, BD Coldewey, C Grabosch, HJ Viani, ALD Meyer, A Monig, K Schlenstedt, S Straub, PB Barbagli, G Gallo, E Pelfer, P Maccarrone, G Votano, L Bamberger, A Eisenhardt, S Markun, P Raach, H Wolfle, S Brook, NH Bussey, PJ Doyle, AT Lee, SW Macdonald, N McCance, GJ Saxon, DH Sinclair, LE Skillicorn, IO Strickland, E Waugh, R Gendner, N Holm, U Meyer-Larsen, A Salehi, H Wick, K Gialas, I Gladilin, LK Kcira, D Klanner, R Lohrmann, E Poelz, G Zetsche, F Bacon, TC Cole, JE Howell, G Lamberti, L Long, KR Miller, DB Prinias, A Sedgbeer, JK Sideris, D Tapper, AD Walker, R Mallik, U Wang, SM Cloth, P Filges, D Ishii, T Kuze, M Suzuki, I Tokushuku, K Yamada, S Yamauchi, K Yamazaki, Y Ahn, SH An, SH Hong, SJ Lee, SB Nam, SW Park, SK Lim, H Park, IH Son, D Barreiro, F Fernandez, JP Garcia, G Glasman, C Hernandez, JM Labarga, L del Peso, J Puga, J Redondo, I Terron, J Corriveau, F Hanna, DS Hartmann, J Murray, WN Ochs, A Padhi, S Riveline, M Stairs, DG St-Laurent, M Wing, M Tsurugai, T Bashkirov, V Dolgoshein, BA Bashindzhagyan, GL Ermolov, PF Golubkov, YA Khein, LA Korotkova, NA Korzhavina, IA Kuzmin, VA Lukina, OY Proskuryakov, AS Shcheglova, LM Solomin, AN Zotkin, SA Botje, M Brummer, N Engelen, J Koffeman, E Kooijman, P van Sighem, A Tiecke, H Tuning, N Velthuis, JJ Verkerke, W Vossebeld, J Wiggers, L de Wolf, E Acosta, D Bylsma, B Durkin, LS Gilmore, J Ginsburg, CM Kim, CL Ling, TY Nylander, P Blaikley, HE Boogert, S Cashmore, RJ Cooper-Sarkar, AM Devenish, RCE Edmonds, JK Grosse-Knetter, J Harnew, N Matsushita, T Noyes, VA Quadt, A Ruske, O Sutton, MR Walczak, R Waters, DS Bertolin, A Brugnera, R Carlin, R Dal Corso, F Dondana, S Dosselli, U Dusini, S Limentani, S Morandin, M Posocco, M Stanco, L Stroili, R Voci, C Iannotti, L Oh, BY Okrasinski, JR Toothacker, WS Whitmore, JJ Iga, Y D'Agostini, G Marini, G Nigro, A Raso, M Cormack, C Hart, JC McCubbin, NA Shah, TP Epperson, D Heusch, C Sadrozinski, HFW Seiden, A Wichmann, R Williams, DC Pavel, N Abramowicz, H Dagan, S Kananov, S Kreisel, A Levy, A Schechter, A Abe, T Fusayasu, T Inuzuka, M Nagano, K Umemori, K Yamashita, T Hamatsu, R Hirose, T Homma, K Kitamura, S Nishimura, T Arneodo, M Cirio, R Costa, M Ferrero, MI Maselli, S Monaco, V Peroni, C Petrucci, MC Ruspa, M Solano, A Staiano, A Dardo, M Bailey, DC Fagerstroem, CP Galea, R Koop, T Levman, GM Martin, JF Orr, RS Polenz, S Sabetfakhri, A Simmons, D Catterall, CD Hayes, ME Heaphy, EA Jones, TW Lane, JB Ciborowski, J Grzelak, G Nowak, RJ Pawlak, JM Pawlak, R Smalska, B Tymieniecka, T Wroblewski, AK Zakrzewski, JA Zarnecki, AF Adamus, M Gadaj, T Deppe, O Eisenberg, Y Hochman, D Karshon, U Badgett, WF Chapin, D Cross, R Foudas, C Mattingly, S Reeder, DD Smith, WH Vaiciulis, A Wildschek, T Wodarczyk, M Deshpande, A Dhawan, S Hughes, VW Bhadra, S Frisken, WR Hall-Wilton, R Khakzad, M Menary, S Schmidke, WB CA ZEUS Collaboration TI Search for contact interactions in deep inelastic e(+)p -> e(+)X scattering at HERA SO EUROPEAN PHYSICAL JOURNAL C LA English DT Article ID CENTRAL TRACKING DETECTOR; ZEUS BARREL CALORIMETER; ATOMIC PARITY VIOLATION; FERMION-PAIR PRODUCTION; MONTE-CARLO GENERATOR; COMPOSITENESS SCALES; PARTON DISTRIBUTIONS; NUCLEON SCATTERING; JET FRAGMENTATION; EVENT GENERATOR AB In a search for signatures of physics processes beyond the Standard Model, various eeqq vector contact-interaction hypotheses have been tested using the high-Q(2) deep inelastic neutral-current e(+)p scattering data collected with the ZEUS detector at HERA. The data correspond to an integrated luminosity of 47.7pb(-1) of e(+)p interactions at 300 GeV center-of-mass energy. No significant evidence of a contact-interaction signal has been found. Limits at the 95% confidence level are set on the contact-interaction amplitudes. The effective mass scales Lambda corresponding to these limits range from 1.7 TeV to 5 TeV for the contact-interaction scenarios considered. C1 Argonne Natl Lab, Argonne, IL 60439 USA. Andrews Univ, Berrien Springs, MI 49104 USA. Univ Bologna, Bologna, Italy. Ist Nazl Fis Nucl, I-40126 Bologna, Italy. Univ Bonn, Inst Phys, D-5300 Bonn, Germany. Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England. Univ Calabria, Dept Phys, I-87036 Cosenza, Italy. Ist Nazl Fis Nucl, I-87036 Cosenza, Italy. Chonnam Natl Univ, Kwangju, South Korea. Columbia Univ, Nevis Labs, Irvington, NY USA. Inst Nucl Phys, Krakow, Poland. Acad Min & Met, Fac Phys & Nucl Tech, Krakow, Poland. Jagiellonian Univ, Dept Phys, Krakow, Poland. DESY, Deutsch Elektronen Synchrotron, Hamburg, Germany. DESY, Zeuthen, Germany. Univ Florence, Florence, Italy. Ist Nazl Fis Nucl, I-50125 Florence, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Freiburg, Fac Phys, Freiburg, Germany. Univ Glasgow, Dept Phys & Astron, Glasgow, Lanark, Scotland. Univ Hamburg, Inst Exp Phys 1, Hamburg, Germany. Univ Hamburg, Inst Expt Phys 2, D-2000 Hamburg, Germany. Univ London Imperial Coll Sci Technol & Med, High Energy Nucl Phys Grp, London, England. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Forschungszentrum, Inst Kernphys, Julich, Germany. KEK, Inst Particle & Nucl Studies, Tsukuba, Ibaraki, Japan. Korea Univ, Seoul 136701, South Korea. Kyungpook Natl Univ, Taegu 702701, South Korea. Univ Autonoma Madrid, Dept Fis Teor, Madrid, Spain. McGill Univ, Dept Phys, Montreal, PQ, Canada. Meiji Gakuin Univ, Fac Gen Educ, Yokohama, Kanagawa, Japan. Moscow Engn Phys Inst, Moscow 115409, Russia. Moscow MV Lomonosov State Univ, Inst Phys Nucl, Moscow, Russia. NIKHEF, Amsterdam, Netherlands. Univ Amsterdam, Amsterdam, Netherlands. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Oxford, Dept Phys, Oxford, England. Univ Padua, Dipartimento Fis, Padua, Italy. Ist Nazl Fis Nucl, Padua, Italy. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Polytech Univ, Sagamihara, Kanagawa, Japan. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Ist Nazl Fis Nucl, I-00185 Rome, Italy. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. Univ Siegen, Fachbereich Phys, D-57068 Siegen, Germany. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys, IL-69978 Tel Aviv, Israel. Univ Tokyo, Dept Phys, Tokyo 113, Japan. Tokyo Metropolitan Univ, Dept Phys, Tokyo, Japan. Univ Turin, Dipartimento Fis Sperimentale, Turin, Italy. Ist Nazl Fis Nucl, I-10125 Turin, Italy. Univ Turin, Fac Sci 2, Alessandria, Italy. Ist Nazl Fis Nucl, Alessandria, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. UCL, Dept Phys & Astron, London, England. Univ Warsaw, Inst Expt Phys, Warsaw, Poland. Inst Nucl Studies, PL-00681 Warsaw, Poland. Weizmann Inst Sci, Dept Particle Phys, IL-76100 Rehovot, Israel. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Yale Univ, Dept Phys, New Haven, CT USA. York Univ, Dept Phys, Toronto, ON M3J 2R7, Canada. Univ Salerno, Naples, Italy. Ist Nazl Fis Nucl, I-80125 Naples, Italy. RP Argonne Natl Lab, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Solomin, Anatoly/C-3072-2016; dusini, stefano/J-3686-2012; Graciani Diaz, Ricardo/I-5152-2016; Capua, Marcella/A-8549-2015; De Pasquale, Salvatore/B-9165-2008; Wing, Matthew/C-2169-2008; Bashkirov, Vladimir/A-4818-2008; Doyle, Anthony/C-5889-2009; Golubkov, Yury/E-1643-2012; Proskuryakov, Alexander/J-6166-2012; Katz, Uli/E-1925-2013; Wiggers, Leo/B-5218-2015; Hernandez Calama, Jose Maria/H-9127-2015; Tassi, Enrico/K-3958-2015; Gladilin, Leonid/B-5226-2011; Morandin, Mauro/A-3308-2016 OI dusini, stefano/0000-0002-1128-0664; Graciani Diaz, Ricardo/0000-0001-7166-5198; Castellini, Guido/0000-0002-0177-0643; Capua, Marcella/0000-0002-2443-6525; De Pasquale, Salvatore/0000-0001-9236-0748; Doyle, Anthony/0000-0001-6322-6195; Katz, Uli/0000-0002-7063-4418; Wiggers, Leo/0000-0003-1060-0520; Hernandez Calama, Jose Maria/0000-0001-6436-7547; Gladilin, Leonid/0000-0001-9422-8636; Morandin, Mauro/0000-0003-4708-4240 NR 57 TC 20 Z9 20 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1434-6044 EI 1434-6052 J9 EUR PHYS J C JI Eur. Phys. J. C PD MAY PY 2000 VL 14 IS 2 BP 239 EP 254 DI 10.1007/s100520000336 PG 16 WC Physics, Particles & Fields SC Physics GA 329AE UT WOS:000087883300004 ER PT J AU Eroles, J Ortiz, G Balatsky, AV Bishop, AR AF Eroles, J Ortiz, G Balatsky, AV Bishop, AR TI Inhomogeneity-induced superconductivity? SO EUROPHYSICS LETTERS LA English DT Article ID T-C; MAGNETIC FLUCTUATIONS; NEUTRON-SCATTERING; SPIN FLUCTUATIONS; LA2-XSRXCUO4; EXCITATIONS; DEPENDENCE; LA1.85SR0.15CUO4; YBA2CU3O6.6; TEMPERATURE AB A t-J-like model for inhomogeneous superconductivity of cuprate oxides is presented, in which local anisotropic magnetic terms are essential. We show that: this model predicts pairing, consistent with experiments, and argue how the macroscopic phase-coherent state gradually grows upon lowering of the temperature. We show that appropriate inhomomogeneities are essential in order to have significant pair binding in the thermodynamic limit. Particularly, local breaking of SU(2) spin symmetry is an efficient mechanism for inducing pairing of two holes, as well as explaining the magnetic scattering properties. We also discuss the connection of the resulting inhomogeneity-induced superconductivity to recent experimental evidence for a linear relation between magnetic incommensurability and the superconducting transition temperature, as a function ol doping. C1 Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. Inst Balseiro, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. RP Eroles, J (reprint author), Los Alamos Natl Lab, Div Theoret, POB 1663, Los Alamos, NM 87545 USA. NR 29 TC 23 Z9 23 U1 0 U2 3 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD MAY PY 2000 VL 50 IS 4 BP 540 EP 546 DI 10.1209/epl/i2000-00303-0 PG 7 WC Physics, Multidisciplinary SC Physics GA 317HZ UT WOS:000087221100018 ER PT J AU West, GB AF West, GB TI Asymptotic series and precocious scaling SO FOUNDATIONS OF PHYSICS LA English DT Article ID ANNIHILATION CROSS-SECTION; LOOP QCD CONTRIBUTION AB A heuristic proof is given that the divergent QCD perturbation series is, asymptotic. By treating it as asymptotic expansion we show that it makes sense to keep only th first few terms. The example of e(+)e(-) annihilation is considered. It is shown that by keeping only the first few terms one can get within a percent (or smaller) of the complete sum of the series even at very low momenta where the coupling is large, More generally, this affords an explanation of the phenomena of precocious scaling and why keeping only leading order corrections generally works so well. C1 Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA. RP West, GB (reprint author), Univ Calif Los Alamos Natl Lab, Div Theoret, MS B285, Los Alamos, NM 87545 USA. NR 7 TC 3 Z9 3 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0015-9018 J9 FOUND PHYS JI Found. Phys. PD MAY PY 2000 VL 30 IS 5 BP 695 EP 704 DI 10.1023/A:1003732910145 PG 10 WC Physics, Multidisciplinary SC Physics GA 349UY UT WOS:000089065000004 ER PT J AU Reyes, S Latkowski, JF Sanz, J AF Reyes, S Latkowski, JF Sanz, J TI The effect of gamma-ray transport on afterheat calculations for accident analysis SO FUSION TECHNOLOGY LA English DT Article ID ACTIVATION AB Radioactive afterheat is an important source term for the release of radionuclides infusion systems under accident conditions. Heat transfer calculations are used to determine time-temperature histories in regions of interest, but the true source term needs to be the "effective afterheat, " which considers the transport of penetrating gamma rays. Without consideration of photon transport, accident temperatures may be overestimated in some regions while being underestimated in others. The importance of this effect is demonstrated for a simple, one-dimensional problem. The significance of this effect depends strongly on the accident scenario being analyzed. C1 Univ Nacl Educ Distancia, Escuela Tecn Super Ingn Ind, Dept Ingn Energet, E-28040 Madrid, Spain. RP Reyes, S (reprint author), Univ Calif Lawrence Livermore Natl Lab, POB 808,L-446, Livermore, CA 94550 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD MAY PY 2000 VL 37 IS 3 BP 225 EP 230 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 309TC UT WOS:000086784500004 ER PT J AU Merrill, BJ AF Merrill, BJ TI Modeling an unmitigated quench event in an ITER toroidal field magnet SO FUSION TECHNOLOGY LA English DT Article AB An unmitigated quench of a toroidadfield (TF) magnet has been proposed as an extremely unlikely event for International Thermonuclear Experimental Reactor (ITER) Engineering Design Activity safety analysis. While the frequency of such an event is highly improbable (<1 x 10(-6)/yr), the public safety consequences of this event must be explored because the TF magnets are located midway between the two primary confinement barriers of the ITER design. These confinement barriers are the vacuum vessel (VV) and the cryostat. An unmitigated quench has the potential for producing melting of the magnet. If molten material from the magnet were to impinge on the walls of the VV and cryostat, these walls could fail, resulting in a pathway for release of radioactive material to the environment from the VV; A model has been developed at the Idaho National Engineering and Environmental Laboratory called MAGARC to investigate the consequences of this accident. This model is described in detail, and results from this model used in ITER safety analysis are presented. C1 Idaho Natl Engn & Environm Lab, Fus Safety Program, Idaho Falls, ID 83415 USA. RP Merrill, BJ (reprint author), Idaho Natl Engn & Environm Lab, Fus Safety Program, POB 1625, Idaho Falls, ID 83415 USA. NR 22 TC 4 Z9 4 U1 0 U2 0 PU AMER NUCLEAR SOCIETY PI LA GRANGE PK PA 555 N KENSINGTON AVENUE, LA GRANGE PK, IL 60525 USA SN 0748-1896 J9 FUSION TECHNOL JI Fusion Technol. PD MAY PY 2000 VL 37 IS 3 BP 231 EP 246 PG 16 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 309TC UT WOS:000086784500005 ER PT J AU Han, CS Sutherland, RD Jewett, PB Campbell, ML Meincke, LJ Tesmer, JG Mundt, MO Fawcett, JJ Kim, UJ Deaven, LL Doggett, NA AF Han, CS Sutherland, RD Jewett, PB Campbell, ML Meincke, LJ Tesmer, JG Mundt, MO Fawcett, JJ Kim, UJ Deaven, LL Doggett, NA TI Construction of a BAC contig map of chromosome 16q by two-dimensional overgo hybridization SO GENOME RESEARCH LA English DT Article ID HUMAN GENOME; YEAST; LIBRARIES; CLONING; CLONES; DNA AB We have used sequence-based markers From an integrated YAC STS-content/somatic cell hybrid breakpoint physical map and radiation hybrid maps of human chromosome 16 to construct a new sequence-ready BAC map of the long arm of this chromosome. The integrated physical map was generated previously in our laboratory and contains 1150 STSs, providing a marker on average every 78 kb on the euchromatic arms of chromosome 16. The other two maps used for this effort were the radiation hybrid maps of chromosome 16 from Whitehead Institute and Stanford University. To create large sequenceable targets of this chromosome, we used a systematic approach to screen high-density BAC Filters with probes generated from overlapping oligonucleotides (overgos). We first identified all available sequences in the three maps. These include sequences from genes, ESTs, STSs, and cosmid end sequences. We then used BLASTto identify 36-bp unique fragments of DNA for over go probes. A total of 906 overgos were selected from the long arm of chromosome 16. Hybridizations occurred in thr ee stages: (I) superpool hybridizations against the 12x coverage human BAC library (RPCI-11); (2) two-dimensional hybridizations against rearrayed positive BACs identified in the superpool hybridizations; and (3) pooled tertiary hybridizations for those overgos that had ambiguous positives remaining after the two-dimensional hybridization. For the superpool hybridizations, up to 236 overgos have been pooled in a single hybridization against the 12x BAC library. A total of 5187 positive BACs from chromosome 16q were identified as a result of five superpool hybridizations. These positive clones were rearrayed on membranes and hybridized with 161 two-dimensional subpools of overgos to determine which BAC clones were positive for individual overgos. An additional 46 tertiary hybridizations were required to resolve ambiguous overgo-BAC relationships. Thus, after a total of 212 hybridizations, we have constructed an initial probe-content BAC map of chromosome 16q consisting of 828 overgo markers and 3363 BACs providing >85% coverage of the long arm of this chromosome. The map has been confirmed by the fingerprinting data and BAC end PCR screening. C1 Univ Calif Los Alamos Natl Lab, DOE Joint Genome Inst, Biosci Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Ctr Human Genome Studies, Los Alamos, NM 87545 USA. CALTECH, Dept Biol, Pasadena, CA 91125 USA. RP Han, CS (reprint author), Univ Calif Los Alamos Natl Lab, DOE Joint Genome Inst, Biosci Div, POB 1663, Los Alamos, NM 87545 USA. NR 17 TC 48 Z9 48 U1 0 U2 4 PU COLD SPRING HARBOR LAB PRESS PI PLAINVIEW PA 1 BUNGTOWN RD, PLAINVIEW, NY 11724 USA SN 1088-9051 J9 GENOME RES JI Genome Res. PD MAY PY 2000 VL 10 IS 5 BP 714 EP 721 DI 10.1101/gr.10.5.714 PG 10 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Genetics & Heredity GA 314UZ UT WOS:000087077100014 PM 10810094 ER PT J AU Coleman, MA Eisen, JA Mohrenweiser, HW AF Coleman, MA Eisen, JA Mohrenweiser, HW TI Cloning and characterization of HARP/SMARCAL1: A prokaryotic HepA-related SNF2 helicase protein from human and mouse SO GENOMICS LA English DT Article ID REPLICATION ERRORS; SEQUENCE; FAMILY; REPAIR; GENE; MUTATIONS; HOMOLOGS; GENOME; MEMBER; CELLS AB The SNF2 gene family consists of a large group of proteins involved in transcriptional regulation, maintenance of chromosome integrity, and various aspects of DNA repair. We cloned a novel SNF2 family human cDNA, with sequence identity to the Escherichia coli RNA polymerase-binding protein HepA and named the human hepA-related protein (HHARP/SMARCAL1). In addition, the mouse ortholog (Mharp/Smarcal1) was cloned, and the Caenorhabditis elegans ortholog (CE-HARP) was identified in the GenBank database. Phylogenetic analysis indicates that the HARP proteins share a high level of sequence similarity to the seven motif helicase core region (SNF2 domain) with identifiable orthologs in other eukaryotic species, except for yeast. Purified His-tagged HARP/SMARCAL1 protein exhibits single-stranded DNA-dependent ATPase activity, consistent with it being a member of the SNF2 family of proteins. Both the human and the mouse genes consist of 17 exons and 16 introns, The human gene maps to chromosome 2q34-q36, and the mouse gene is localized to the syntenic region of chromosome 1 (between markers Gls and Acrg). HARP/SMARCAL1 transcripts are ubiquitously expressed in human and mouse tissues, with testis presenting the highest levels of mRNA expression in humans. (C) 2000 Academic Press. C1 Univ Calif Lawrence Livermore Natl Lab, Biol & Biotechnol Res Program, Livermore, CA 94551 USA. Stanford Univ, Dept Biol Sci, Stanford, CA 94305 USA. RP Coleman, MA (reprint author), Univ Calif Lawrence Livermore Natl Lab, BBRP, L-448,7000 East Ave, Livermore, CA 94550 USA. OI Coleman, Matthew/0000-0003-1389-4018; Eisen, Jonathan A./0000-0002-0159-2197 NR 35 TC 42 Z9 45 U1 0 U2 1 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0888-7543 J9 GENOMICS JI Genomics PD MAY 1 PY 2000 VL 65 IS 3 BP 274 EP 282 DI 10.1006/geno.2000.6174 PG 9 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 315RV UT WOS:000087127500009 PM 10857751 ER PT J AU Duff, MC Morris, DE Hunter, DB Bertsch, PM AF Duff, MC Morris, DE Hunter, DB Bertsch, PM TI Spectroscopic characterization of uranium in evaporation basin sediments SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID LASER-INDUCED FLUORESCENCE; SAN-JOAQUIN VALLEY; X-RAY-FLUORESCENCE; LUMINESCENCE SPECTRA; CONTAMINATED SOIL; HUMIC SUBSTANCES; SPECIATION; REDUCTION; PHASES; ACID AB Evaporation ponds in the San Joaquin Valley (SJV), CA, used for the containment of irrigation drainage waters contain elevated levels of uranium (U) resulting from the extensive leaching by carbonate-rich irrigation waters of the local agricultural soils that contain low levels of naturally-occurring U. The SJV ponds are subjected to changes in redox chemistry with cycles of drying and flooding. Our past studies have shown that U in the SJV Pond 14 surface sediments is present as mostly the oxidized and soluble form, U(VI). However, we were uncertain whether the U in the soil was only present as a U oxide of mixed stoichiometry, such as U3O8(s) (pitchblende) or other species. Here we present characterization information, which includes wet chemical and in situ spectroscopic techniques (X-ray absorption near-edge structure (XANES) and low temperature time-resolved luminescence spectroscopies) for samples from two SJV Pond sediments. Surface sediments from SJV Pond 16 were characterized for average oxidation state of U with XANES spectroscopy. The fraction of U(VI) to U(IV) in the Pond 16 sediments decreased with depth with U(IV) being the dominant oxidation state in the 5 cm to 15 cm depth. Two luminescent U(VI) species were identified in the surface sediments from Pond 14; a U(VI)-tricarbonate phase and another phase likely comprised of U(VI)-hydroxide or hydroxycarbonate. The luminescent U(VI) population in the Pond 16 sediments is dominated by species with comparable spectral characteristics to the U(VI)-hydroxide or hydroxycarbonate species found in the Pond 14 sediments. The luminescence spectroscopic results were complemented by wet chemical U leaching methods, which involved the use of carbonate and sulfuric acid solutions and oxidizing solutions of peroxide, hypochlorite and Mn(IV). Leaching was shown to decrease the total U concentration in the sediments in all cases. However, results from luminescence studies of the residual fraction in the leached sediments suggest that there was no selectivity in the removal of the spectroscopically identifiable U(VT) species by acidic oxidizing, basic oxidizing or basic non-oxidizing solutions. A net increase in the emission intensity of the U(VI) luminescent species in most leached samples was consistent with conversion of U(IV) to U(VI), as a result of chemical oxidation and exposure to air during the leaching process. The wet chemical extractions and in situ spectroscopic techniques provided fundamental and basic knowledge about the fraction of U(IV) to U(VI), the speciation of luminescent U(VI), and the susceptibility of the sediment U species to leaching. Copyright (C) 2000 Elsevier Science Ltd. C1 Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Aiken, SC 29802 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. Univ Calif Los Alamos Natl Lab, Glenn T Seaborg Inst Transactinium Sci, Los Alamos, NM 87545 USA. RP Duff, MC (reprint author), Univ Georgia, Savannah River Ecol Lab, Adv Analyt Ctr Environm Sci, Drawer E, Aiken, SC 29802 USA. RI Morris, David/A-8577-2012 NR 57 TC 36 Z9 36 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2000 VL 64 IS 9 BP 1535 EP 1550 DI 10.1016/S0016-7037(99)00410-X PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 308UZ UT WOS:000086732400005 ER PT J AU Rustad, JR Dixon, DA Felmy, AR AF Rustad, JR Dixon, DA Felmy, AR TI Intrinsic acidity of aluminum, chromium (III) and iron (III) mu(3)-hydroxo functional groups from ab initio electronic structure calculations SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SOLID-SOLUTION INTERFACE; FORMATION-CONSTANTS; HARTREE-FOCK; DENSITY; SURFACE; COMPLEXATION; HYDROLYSIS; ADSORPTION; ENERGY; APPROXIMATION AB Density functional calculations are performed on M-3(OH)(7)(H2O)(6)(2+) and M3O(OH)(6)(H2O)(6)(+) clusters for M=Al, Cr(III), and Fe(III), allowing determination of the relative acidities of the mu(3)-hydroxo and aquo functional groups. Contrary to previous predictions and rationalizations, =Fe3OH and =Al3OH groups have nearly the same intrinsic acidity, while =Cr3OH groups are significantly more acidic. The gas-phase acidity of the Fe3OH site is in good agreement with the value predicted by the molecular mechanics model previously used to estimate the relative acidities of surface sites on iron oxides. [J. R. Rustad et al. (1996) Geochim. Cosmochim. Acta 60, 1563]. Acidities of aquo functional groups were also computed for Al and Cr. The =AlOH2 site is more acidic than the =Al3OH site, whereas the =Cr3OH site is more acidic than the =CrOH2 site. These findings predict that the surface charging behavior of chromium oxides/oxyhydroxides should be distinguishable from their Fe, Al counterparts. The calculations also provide insight into why the lepidocrocite/boehmite polymorph is not observed for CrOOH. Copyright (C) 2000 Elsevier Science Ltd. C1 Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. RP Rustad, JR (reprint author), Pacific NW Natl Lab, William R Wiley Environm Mol Sci Lab, Richland, WA 99352 USA. NR 31 TC 21 Z9 21 U1 2 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAY PY 2000 VL 64 IS 10 BP 1675 EP 1680 DI 10.1016/S0016-7037(99)00384-1 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 313MV UT WOS:000087004200002 ER PT J AU Mack, GH Cole, DR Trevino, L AF Mack, GH Cole, DR Trevino, L TI The distribution and discrimination of shallow, authigenic carbonate in the Pliocene-Pleistocene Palomas Basin, southern Rio Grande rift SO GEOLOGICAL SOCIETY OF AMERICA BULLETIN LA English DT Article DE authigenesis; isotopes; paleosols; Pleistocene; Pliocene; Rio Grande rift ID QUATERNARY CLIMATIC CHANGES; PLIOPLEISTOCENE CAMP RICE; STABLE ISOTOPE CHEMISTRY; EASTERN MOJAVE DESERT; K-AR DATES; NEW-MEXICO; YUCCA-MOUNTAIN; SOUTHWESTERN AUSTRALIA; PEDOGENIC CARBONATES; CALCIFIED FILAMENTS AB Nine types of authigenic carbonate are present in the Plioccne-Pleistocene alluvial-fan and axial-fluvial sediment of the Palomas half graben in the southern Rio Grande rift. Pedogenic and other vadose carbonate includes (1) pedogenic carbonate of stage II and stage III morphology underlying Bm and Bt horizons, (2) mudstones in which the carbonate nodules may be pedogenic or the result of shallow groundwater invasion of the vadose zone, (3) pedogenic calcic nodules and tubules in eolian sand, and (4) gully-bed cement of proximal-fan conglomerates formed by infiltration and evaporation of surface runoff Shallow groundwater carbonate exists as (5) thin (30-50 cm), massive beds with an upper fringe of nodules and tubules precipitated at the water table and in the capillary fringe, (6) thick (1.5-3 m), massive beds deposited by lateral flow of groundwater or at springs, and (7) thin (30 cm) calcified root mats associated with near-surface, water-saturated sediment or springs. Phreatic spar cements (8) occupy the interstices of conglomerates and sandstones and locally exist as (9) oriented concretions. Groundwater carbonates are best developed near the toes of the large, hanging-wall-derived alluvial fans, whereas phreatic cement preferentially exists in footwall-derived, alluvial-fan conglomerates. Pedogenic carbonate is distinguished from groundwater carbonate by the association with other diagnostic paleosol horizons, a predominantly vertical arrangement of root traces, peds, desiccation cracks, and calcic tubules, and by gradational contacts, The delta(13)C and delta(18)O values are similar among pedogenic and shallow groundwater carbonate, although locally nodules in eolian sand and gully-bed cement have higher delta(18)O values, perhaps due to the effects of evaporation. Some phreatic cements mag be distinguished from pedogenic and shallow groundwater carbonate by lon er values of delta(13)C and delta(18)O. Authigenic carbonate in footwall-derived, alluvial-fan sediment has consistently higher values of delta(13)C than that in hanging-wall-derived sediment, which may reflect differences in vegetative type and/or density on either side of the basin. C1 New Mexico State Univ, Dept Geol Sci, Las Cruces, NM 88003 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Mack, GH (reprint author), New Mexico State Univ, Dept Geol Sci, Las Cruces, NM 88003 USA. NR 95 TC 56 Z9 59 U1 0 U2 9 PU ASSOC ENGINEERING GEOLOGISTS GEOLOGICAL SOCIETY AMER PI COLLEGE STN PA TEXAS A & M UNIV, DEPT GEOLOGY & GEOPHYSICS, COLLEGE STN, TX 77843-3115 USA SN 0016-7606 J9 GEOL SOC AM BULL JI Geol. Soc. Am. Bull. PD MAY PY 2000 VL 112 IS 5 BP 643 EP 656 DI 10.1130/0016-7606(2000)112<0643:TDADOS>2.3.CO;2 PG 14 WC Geosciences, Multidisciplinary SC Geology GA 308BV UT WOS:000086689400001 ER PT J AU Gary, SP Yin, L Winske, D Reisenfeld, DB AF Gary, SP Yin, L Winske, D Reisenfeld, DB TI Electromagnetic alpha/proton instabilities in the solar wind SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PROTON/PROTON INSTABILITIES; CYCLOTRON-RESONANCE; ACCELERATION; IONS; SIMULATIONS; PROTONS; WAVES AB The average flow speed of alpha particles relative to protons in the solar wind is observed to be of the order of or less than the Alfven speed. This flow, if sufficiently large, can lead to two distinct types of electromagnetic alpha/proton instabilities: magnetosonic and Alfven. Spatially homogeneous two-dimensional hybrid simulations of collisionless plasmas are used to study these growing modes and the consequent wave-particle scattering of each ion component. This scattering reduces the alpha/proton average flow speed, heats the alphas more strongly than the protons, and increases the alpha temperature in the directions perpendicular to the background magnetic field, all of which are consistent with solar wind observations. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Gary, SP (reprint author), Univ Calif Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. RI Reisenfeld, Daniel/F-7614-2015 NR 21 TC 40 Z9 41 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 2000 VL 27 IS 9 BP 1355 EP 1358 DI 10.1029/2000GL000019 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 309BX UT WOS:000086748600030 ER PT J AU Herman, GC Milligan, PA Dong, QC Rector, JW AF Herman, GC Milligan, PA Dong, QC Rector, JW TI Analysis and removal of multiply scattered tube waves SO GEOPHYSICS LA English DT Article ID SURFACE-WAVES; IRREGULAR BOREHOLE; PROPAGATION AB Because of irregularities in or near the borehole, vertical seismic profiling (VSP) or crosswell data can be contaminated with scattered tube waves. These can have a large amplitude and can interfere with weaker upcoming reflections, destroying their continuity. This type of organized noise cannot always be removed with filtering methods currently in use. We propose a method based on modeling the scattered tube-wave field and then subtracting it from the total data set. We assume that the scattering occurs close to the borehole axis and therefore use a 1-D impedance function to characterize borehole irregularities. Estimation of this impedance function is one of the first steps. Our method also accounts for multiply scattered tube waves. We apply the method to an actual VSP data set and conclude that the continuity of reflected, upcoming events improves significantly in a washout zone. C1 Delft Univ Technol, Dept Appl Anal, NL-2628 CD Delft, Netherlands. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Mineral Engn, Berkeley, CA 94720 USA. RP Herman, GC (reprint author), Delft Univ Technol, Dept Appl Anal, Mekelweg 4, NL-2628 CD Delft, Netherlands. NR 20 TC 12 Z9 13 U1 0 U2 1 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 USA SN 0016-8033 J9 GEOPHYSICS JI Geophysics PD MAY-JUN PY 2000 VL 65 IS 3 BP 745 EP 754 DI 10.1190/1.1444773 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 325BJ UT WOS:000087656200005 ER PT J AU Xie, GQ Li, JH Majer, EL Zuo, DX Oristaglio, ML AF Xie, GQ Li, JH Majer, EL Zuo, DX Oristaglio, ML TI 3-D electromagnetic modeling and nonlinear inversion SO GEOPHYSICS LA English DT Article ID EQUATION AB We describe a new algorithm for 3-D electromagnetic inversion that uses global integral and local differential equations for both the forward and inverse problems. The coupled integral and differential equations are discretized by the finite element method and solved on a parallel computer using domain decomposition. The structure of the algorithm allows efficient solution of large 3-D inverse problems. Tests on both synthetic and field data show that the algorithm converges reliably and efficiently and gives high-resolution conductivity images. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Berkeley, CA 94720 USA. Schlumberger Doll Res Ctr, EMG Dept, Ridgefield, CT 06877 USA. RP Xie, GQ (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Earth Sci, Bldg 90,1 Cyclotron Rd, Berkeley, CA 94720 USA. NR 41 TC 26 Z9 33 U1 0 U2 5 PU SOC EXPLORATION GEOPHYSICISTS PI TULSA PA 8801 S YALE ST, TULSA, OK 74137 USA SN 0016-8033 J9 GEOPHYSICS JI Geophysics PD MAY-JUN PY 2000 VL 65 IS 3 BP 804 EP 822 DI 10.1190/1.1444779 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 325BJ UT WOS:000087656200011 ER PT J AU Brady, PV Bethke, CM AF Brady, PV Bethke, CM TI Beyond the K-d approach SO GROUND WATER LA English DT Editorial Material C1 Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. Dept Geol, Hydrogeol Program, Urbana, IL 61801 USA. RP Brady, PV (reprint author), Sandia Natl Labs, Dept Geochem, MS-0750,POB 5800, Albuquerque, NM 87185 USA. NR 3 TC 7 Z9 7 U1 1 U2 3 PU GROUND WATER PUBLISHING CO PI WESTERVILLE PA 601 DEMPSEY RD, WESTERVILLE, OH 43081 USA SN 0017-467X J9 GROUND WATER JI Ground Water PD MAY-JUN PY 2000 VL 38 IS 3 BP 321 EP 322 PG 2 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 326WY UT WOS:000087761300001 ER PT J AU Bethke, CM Brady, PV AF Bethke, CM Brady, PV TI How the K-d approach undermines ground water cleanup SO GROUND WATER LA English DT Article ID REACTIVE TRANSPORT; EQUILIBRIUM CHEMISTRY; SORPTION; ADSORPTION; CADMIUM; METALS; MODEL; CONTAMINANTS; SIMULATION; RETENTION AB Environmental scientists have long appreciated that the distribution coefficient (the "K-d" or "constant K-d") approach predicts the partitioning of heavy metals between sediment and ground water inaccurately; nonetheless, transport models applied to problems of environmental protection and ground mater remediation almost invariably employ this technique, To examine the consequences of this practice, we consider transport in one dimension of Pb and other heavy metals through an aquifer containing hydrous ferric oxide, onto which many heavy metals sorb strongly, We compare the predictions of models calculated using the Ii, approach to those given by surface complexation theory, which is more realistic physically and chemically. The two modeling techniques give qualitatively differing results that lead to divergent cleanup strategies. The results for surface complexation theory show that water flushing is ineffective at displacing Pb from the sorbing surface. The effluent from such treatment contains a persistent "tail" of small but significant levels of contamination, Subsurface zones of Pb contamination, furthermore, do not migrate rapidly or far in flowing ground water These results stand in sharp contrast to the predictions of models constructed using the K-d approach, yet are consistent with experience in the laboratory and field. C1 Dept Geol, Hydrogeol Program, Urbana, IL 61801 USA. Sandia Natl Labs, Dept Geochem, Albuquerque, NM 87185 USA. RP Bethke, CM (reprint author), Dept Geol, Hydrogeol Program, 1301 W Green St, Urbana, IL 61801 USA. EM c-bethke@uiuc.edu; pvbalb@swcp.com NR 39 TC 77 Z9 77 U1 2 U2 17 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0017-467X EI 1745-6584 J9 GROUND WATER JI Ground Water PD MAY-JUN PY 2000 VL 38 IS 3 BP 435 EP 443 DI 10.1111/j.1745-6584.2000.tb00230.x PG 9 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 326WY UT WOS:000087761300021 ER PT J AU Durbin, PW Kullgren, B Ebbe, SN Xu, JD Raymond, KN AF Durbin, PW Kullgren, B Ebbe, SN Xu, JD Raymond, KN TI Chelating agents for uranium(VI): 2. Efficacy and toxicity of tetradentate catecholate and hydroxypyridinonate ligands in mice SO HEALTH PHYSICS LA English DT Article DE chelation; uranium; kidneys; mice ID IN-VIVO CHELATION; SEQUESTERING AGENTS; URANYL-NITRATE; ACTINIDES; RAT; INTOXICATION; PU-238(IV); RETENTION; REMOVAL; PU(IV) AB Uranium(VI) (UO22+, uranyl) is nephrotoxic. Depending on isotopic composition and dosage, U(VI) is also chemically toxic and carcinogenic in bone. Several ligands containing two, three, or four bidentate catecholate or hydroxypyridinonate metal binding groups, developed for in vivo chelation of other actinides, were found, on evaluation in mice, to be effective far in vivo chelation of U(TI). The most promising ligands contained two bidentate groups per chelator molecule (tetradentate) attached to linear 4- or 5-carbon backbones (4-LI, butylene; 5-LI, pentylene; 5-LIO, diethyl ether). New ligands were then prepared to optimize ligand affinity for U(VI) in vivo and low acute toxicity. Five bidentate binding groups-sulfocatechol [CAM(S)], carboxycatechol [CAM(C)], methylterephthalamide (MeTAM), 1,2-hydroxypyridinone (1,2-HOPO), or 3,2- hydroxypyridinone (Me-3,2-HOPO)-were each attached to two linear backbones (4-LI and 5-LI or 5-LIO), Those ten tetradentate ligands and octadentate 3,4,3-LI(1,2-HOPO), an effective actinide chelator, were evaluated in mice for in vivo chelation of U-233(VI) (injection at 3 min, 1 h, or 24 h or oral administration at 3 min after intravenous injection of (UO2Cl2)-U-233) and for acute toxicity (100 mu mol kg(-1) injected daily for 10 d), The combined efficacy and toxicity screening identified 5-LIO(Me-3,2-HOPO) and 5-LICAM(S) as the most effective low-toxicity agents. They chelate circulating U(VI) efficiently at ligand:uranium molar ratios greater than or equal to 20, remove useful amounts of newly deposited U(VI) from kidney and bone at molar ratios greater than or equal to 100, and reduce kidney U(VT) levels significantly when given orally at molar ratios greater than or equal to 100. 5-LIO(Me-3,2-HOPO) has greater affinity for kidney U(VI) while 5-LICAM(S) has greater affinity for bone U(VI), and a 1:1 mixture (total molar ratio = 91) reduced kidney and bone U(VI) to 15 and 58% of control, respectively-more than an equimolar amount of either ligand alone. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM pwdurbin-heavy@LBL.gov FU NIEHS NIH HHS [ES02698] NR 46 TC 50 Z9 60 U1 3 U2 15 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 MAY PY 2000 VL 78 IS 5 BP 511 EP 521 DI 10.1097/00004032-200005000-00008 PG 11 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 304TR UT WOS:000086500700008 PM 10772024 ER PT J AU Peterson, SR Davis, PA AF Peterson, SR Davis, PA TI Modeled concentrations in rice and ingestion doses from chronic atmospheric releases of tritium SO HEALTH PHYSICS LA English DT Article DE tritium; ingestion; modeling, dose assessment; emissions, atmospheric ID FALLOUT H-3 INGESTION; VEGETATION; PLANTS; AKITA; JAPAN; AIR AB The expansion of nuclear power programs in Asia has stimulated interest in the improved modeling of concentrations of tritium in rice, a staple crop grown throughout the far east. Normally the specific activity model is used to calculate concentrations of tritium in the tissue mater of edible plants to assess ingestion dose from chronic releases, However, because rice, like other grains, has much lower water content than most crops, the calculation must also account for organically bound tritium, This paper reviews ways to calculate steady-state concentrations of tritium in rice, including the methods of Canadian and United States regulatory models, and the assumptions behind them. Concentrations in rice and resulting ingestion doses are compared for the various methods, and equations for calculating concentrations are recommended. The regulatory models underestimate doses received from ingestion of rice contaminated with tritium since they do not account explicitly for organically bound tritium, The importance of including organically bound tritium is illustrated in a comparison of doses from rice, leafy vegetables and milk for an Asian diet. Dose factors from tritium for these foods are estimated to be 135, 47, and 20 nSv y(-1)/(Bq m(-3)), respectively. Assuming known air concentrations, tritium concentrations in rice, calculated with the recommended equations, are uncertain by less than a factor 2 when tritium concentrations in the rice paddy mater are known, and by less than a factor of 2.3 when concentrations in paddy mater are unknown. C1 Atom Energy Canada Ltd, Chalk River Nucl Labs, Environm Res Branch, Chalk River, ON K0J 1J0, Canada. Univ Calif Lawrence Livermore Natl Lab, Environm Protect Dept, Operat & Regulatory Affairs Div, Terr Atmospher Monitoring & Modeling Grp, Livermore, CA 94551 USA. EM davisp@aecl.ca NR 28 TC 11 Z9 11 U1 0 U2 2 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD MAY PY 2000 VL 78 IS 5 BP 533 EP 541 DI 10.1097/00004032-200005000-00011 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 304TR UT WOS:000086500700011 PM 10772027 ER PT J AU Degteva, MO Vorobiova, MI Kozheurov, VP Tolstykh, EI Anspaugh, LR Napier, BA AF Degteva, MO Vorobiova, MI Kozheurov, VP Tolstykh, EI Anspaugh, LR Napier, BA TI Dose reconstruction system for the exposed population living along the Techa River SO HEALTH PHYSICS LA English DT Article DE contamination, environmental; Sr-90; biokinetics; dose assessment ID HUMAN BONE; ISSUES; REGION AB The Mayak Production Association, which began operation in 1948, was the first facility in the former Soviet Union for the production of plutonium. Significant worker and population exposure occurred as a result of failures in the technological processes in the late 1940's and early 1950's. Members of the public were exposed via discharge of about 10(17) Bq of liquid wastes into the Techa River during 1949-1956, an explosion in the radioactive waste-storage facility in 1957, and gaseous aerosol releases within the first decades of the facility's operation. Residents of many villages downstream on the Techa River were exposed via a variety of pathways; the more significant included drinking of water from the river and external gamma exposure due to proximity to sediments and shoreline, The specific aim of this project is to enhance the reconstruction of external and internal radiation doses for individuals in the Extended Techa River Cohort. The purpose of this paper is to present the details of the methods that are being used in this enhanced dose-reconstruction effort and to provide example and representative results of the calculations, The methods of dose assessment currently being developed for the exposed population [termed the Techa River Dosimetry System-2000 (TRDS-2000)], which are a significant improvement on past methods (TRDS-1996), are presented. The new TRDS-2000 doses from the ingestion of radionuclides are substantially higher for the gastrointestinal tract, due to consideration of short-lived radionuclides, The TRDS-2000 doses from external exposure are substantially lower due to improvements in several factors. Assessment of uncertainty and validation of the "new" doses are significant issues currently under investigation. C1 Urals Res Ctr Radiat Med, Chelyabinsk, Russia. Univ Utah, Div Radiobiol, Salt Lake City, UT 84117 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. EM LAnspaugh@aol.com NR 27 TC 60 Z9 68 U1 1 U2 4 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 MAY PY 2000 VL 78 IS 5 BP 542 EP 554 DI 10.1097/00004032-200005000-00012 PG 13 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 304TR UT WOS:000086500700012 PM 10772028 ER PT J AU Fisher, DR AF Fisher, DR TI Decorporation: Officially a word SO HEALTH PHYSICS LA English DT Article DE radionuclide; chelation; education, health physics; medical radiation AB This note is the brief history of a word. Decorporation is a scientific term known to health physicists who have an interest in the removal of internally deposited radionuclides from the body after an accidental or inadvertent intake. Although the word decorporation appears many times in the radiation protection literature, it was only recently accepted by the editors of the Oxford English Dictionary as an entry for their latest edition. C1 Pacific NW Natl Lab, Hanford Radioisotopes & Med Sci Program, Richland, WA 99352 USA. EM dr.fisher@pnl.gov NR 17 TC 8 Z9 8 U1 0 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 MAY PY 2000 VL 78 IS 5 BP 563 EP 565 DI 10.1097/00004032-200005000-00015 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 304TR UT WOS:000086500700015 PM 10772031 ER PT J AU Panchal, CB Watkinson, AP Bott, TR AF Panchal, CB Watkinson, AP Bott, TR TI Fouling mitigation: Challenges and opportunities SO HEAT TRANSFER ENGINEERING LA English DT Editorial Material C1 Argonne Natl Lab, Argonne, IL 60439 USA. Univ British Columbia, Vancouver, BC V5Z 1M9, Canada. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. RP Panchal, CB (reprint author), Argonne Natl Lab, Argonne, IL 60439 USA. NR 0 TC 1 Z9 1 U1 0 U2 5 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD MAY-JUN PY 2000 VL 21 IS 3 BP 1 EP 2 PG 2 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 318AW UT WOS:000087262100001 ER PT J AU Panchal, CB Huangfu, EP AF Panchal, CB Huangfu, EP TI Effects of mitigating fouling on the energy efficiency of crude-oil distillation SO HEAT TRANSFER ENGINEERING LA English DT Article; Proceedings Paper CT 1999 Engineering Foundation Conference on Mitigation of Heat Exchanger Fouling and Its Economics and Environmental Implications CY 1999 CL CANADA SP Engn Fdn AB An analysis was performed to determine the effects of fouling of the preheat train on the energy efficiency of a typical crude-distillation unit with a capacity of 100, 000 bbl/day. A spreadsheet analysis was developed to calculate the thermal duty for each of the hear exchanger groups that heat the crude oil from ambient conditions to the distillation temperature. A fouling-rate model del eloped in a previous study was applied to calculate the fouling resistance as a function of time. Improvements in the energy efficiency were analyzed for different mitigation scenarios. The analysis shows economic incentives for new and improved techniques for mitigating fouling of the preheat train. C1 Argonne Natl Lab, Div Energy Syst, Chem & Biol Technol Sect, Argonne, IL 60439 USA. US Dept Energy, Washington, DC USA. RP Panchal, CB (reprint author), Argonne Natl Lab, Div Energy Syst, Chem & Biol Technol Sect, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 11 TC 24 Z9 24 U1 1 U2 7 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD MAY-JUN PY 2000 VL 21 IS 3 BP 3 EP 9 PG 7 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 318AW UT WOS:000087262100002 ER PT J AU Asomaning, S Panchal, CB Liao, CF AF Asomaning, S Panchal, CB Liao, CF TI Correlating field and laboratory data for crude oil fouling SO HEAT TRANSFER ENGINEERING LA English DT Article; Proceedings Paper CT 1999 Engineering Foundation Conference on Mitigation of Heat Exchanger Fouling and Its Economics and Environmental Implications CY 1999 CL CANADA SP Engn Fdn AB Crude oil fouling in a laboratory fouling unit was investigated. The study focused on the preheat-train heat exchangers located just before the crude unit furnace and operating at temperatures in excess of 200 degrees C. A fooling rate model developed using laboratory data from crude blends was used to predict the threshold conditions where negligible fouling was expected under refinery conditions. The results from the model were compared to actual data from a fouling unit located at a refinery. The article discusses factors thar may explain the performance of the model and the observed discrepancies between fouling data obtained in the laboratory and the field. C1 Argonne Natl Lab, Div Energy Syst, Chem & Biol Technol Sect, Argonne, IL 60439 USA. Baker Petrolite Corp, Fluids Separat Div, Sugar Land, TX USA. Equilon Enterprise, Houston, TX USA. RP Panchal, CB (reprint author), Argonne Natl Lab, Div Energy Syst, Chem & Biol Technol Sect, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 14 Z9 17 U1 1 U2 11 PU HEMISPHERE PUBL CORP PI BRISTOL PA 1900 FROST ROAD, SUITE 101, BRISTOL, PA 19007-1598 USA SN 0145-7632 J9 HEAT TRANSFER ENG JI Heat Transf. Eng. PD MAY-JUN PY 2000 VL 21 IS 3 BP 17 EP 23 PG 7 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 318AW UT WOS:000087262100004 ER PT J AU Zhu, SJ Wang, MG Zhu, LY Li, M Gan, CY Sakhaee, YLMM Pau, SL Deng, JK Long, GL Hamilton, JH Ramayya, AV Babu, BRS Hwang, JK Ma, WC Komicki, J Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Stoyer, MA Chu, SY Gregorich, KE Mohar, MF Prussin, SG Lee, IY Oganessian, YT Ter-Akopian, GM Daniel, AV AF Zhu, SJ Wang, MG Zhu, LY Li, M Gan, CY Sakhaee, YLMM Pau, SL Deng, JK Long, GL Hamilton, JH Ramayya, AV Babu, BRS Hwang, JK Ma, WC Komicki, J Cole, JD Aryaeinejad, R Drigert, MW Rasmussen, JO Stoyer, MA Chu, SY Gregorich, KE Mohar, MF Prussin, SG Lee, IY Oganessian, YT Ter-Akopian, GM Daniel, AV TI Octupole deformation in neutron-rich La-145,La-147 nuclei SO HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION LA Chinese DT Article DE nuclear structure; high spin states; octupole deformation; spontaneous fission ID NEUTRON-RICH; SPONTANEOUS FISSION; BARIUM ISOTOPES; XE-139; MASS AB The level schemes with high spin states in neutron-rich(145),(147) La nuclei have been established from the study of prompt gamma-rays emitted in the spontaneous fission of Cf-252. Many new levels and gamma transitions have been identified. The highest spin states in both nuclei were expanded up to (41/2(+)) and (43/2(-)) respectively. The alternating parity band structures and strong E 1 transitions between negative-and positive-parity bands show strong octupole deformation. The collective bands observed in(145) La give evidence for infinity-existence and competition between symmetric and asymmetric shapes. From the systematic comparison with the neighboring isotones, the s = + i bands in both nuclei most probably originate from the single-particle pi h(11/2) orbital coupling with the neighboring even-even cores, respectively. Band crossing of the pi h(11/2) bands was found around h omega approximate to 0.26-0.30MeV and these backbends are related to the alignment of two i(13/2) neutrons from cranked shell model calculations. C1 Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. Mississippi State Univ, Dept Phys, Mississippi State, MS 39762 USA. Idaho Natl Engn Lab, Idaho Falls, ID 83415 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Dubna Joint Nucl Res Inst, Dubna 141980, Russia. RP Zhu, SJ (reprint author), Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA. RI Long, Gui Lu/B-8988-2014 OI Long, Gui Lu/0000-0002-9023-1579 NR 20 TC 2 Z9 2 U1 0 U2 3 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 0254-3052 J9 HIGH ENERG PHYS NUC JI High Energy Phys. Nucl. Phys.-Chin. Ed. PD MAY PY 2000 VL 24 IS 5 BP 418 EP 425 PG 8 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 318KG UT WOS:000087282600008 ER PT J AU Matthews, W Cottrell, L AF Matthews, W Cottrell, L TI The PingER project: Active Internet performance monitoring for the HENP community SO IEEE COMMUNICATIONS MAGAZINE LA English DT Article AB The extraordinary network challenges presented by high energy nuclear and particle physics experiments has created a need for network monitoring both to understand present performance and to allocate resources to optimize performance between laboratories, and the universities and institutes collaborating on present and future experiments. The resulting Internet End-to-End Performance Monitoring project is called PingER. The monitoring infrastructure reflects the wide geographical spread of the collaborations, and involves a large number of research and commercial networks. The architecture of the data acquisition and methodology of the analysis have evolved over several years, and are described here in their present state. The strengths and weaknesses of the project are reviewed, and the derived metrics are discussed in terms of their diagnostic functions. The observed short-term effects and long-term trends are reviewed, and plans for future developments are described. C1 Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. RP Matthews, W (reprint author), Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. NR 5 TC 48 Z9 59 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0163-6804 J9 IEEE COMMUN MAG JI IEEE Commun. Mag. PD MAY PY 2000 VL 38 IS 5 BP 130 EP 136 DI 10.1109/35.841837 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 311PP UT WOS:000086893400020 ER PT J AU Bethel, W AF Bethel, W TI Visualization dot com SO IEEE COMPUTER GRAPHICS AND APPLICATIONS LA English DT Editorial Material C1 Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. RP Bethel, W (reprint author), Univ Calif Berkeley, Lawrence Berkeley Natl Lab, M-S 50F, Berkeley, CA 94720 USA. NR 5 TC 8 Z9 10 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0272-1716 J9 IEEE COMPUT GRAPH JI IEEE Comput. Graph. Appl. PD MAY-JUN PY 2000 VL 20 IS 3 BP 17 EP 20 DI 10.1109/38.844367 PG 4 WC Computer Science, Software Engineering SC Computer Science GA 306YE UT WOS:000086625600004 ER PT J AU Fardi, HZ Winston, DW Hayes, RE Hanna, MC AF Fardi, HZ Winston, DW Hayes, RE Hanna, MC TI Numerical modeling of energy balance equations in quantum well AlxGa1-xAs/GaAs p-i-n photodiodes SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE energy balance; hot electron solar cells; p-i-n; quantum well; SimWindows ID THERMIONIC EMISSION; BIPOLAR-TRANSISTORS; SOLAR-CELLS; SIMULATION; DEVICE; HETEROJUNCTION; ENHANCEMENT; TRANSPORT; GAAS AB The energy balance equations coupled with drift diffusion transport equations in heterojunction semiconductor devices are solved modeling hot electron effects in single quantum well p-i-n photodiodes, The transports across the heterojunction boundary and through quantum wells are modeled by thermionic emission theory. The simulation and experimental current-voltage characteristics of a single p-i-n GaAs/AlalphaGa1-alphaAs quantum well agree over a wide range of current and voltage. The GaAs/A1(alpha)Ga(1-alpha)As p-i-n structures with multi quantum wells are simulated and the dark current-voltage characteristics, short circuit current, and open circuit voltage results are compared with the available experimental data. In agreement with the experimental data, simulated results show that by adding GaAs quantum wells to the conventional cell made of wider bandgap AlalphaGa1-alphaAs, improve short circuit current, but with the loss of the voltage of the host cell. In the limit of radiative recombination, the maximum power point of an Al(0.3)5Ga(0.65)As/GaAs p-i-n photodiode with 30-quantum-well periods is higher than the maximum power point of similar conventional bulk p-i-n cells made out of either host Al0.35Ga0.65As or bulk GaAs material. C1 Univ Colorado, Dept Elect Engn, Denver, CO 80217 USA. IBM Corp, Hopewell Junction, NY 12533 USA. Univ Colorado, Dept Elect & Comp Engn, Boulder, CO 80309 USA. Natl Renewable Energy Lab, Golden, CO 80401 USA. RP Fardi, HZ (reprint author), Univ Colorado, Dept Elect Engn, Denver, CO 80217 USA. NR 28 TC 11 Z9 11 U1 0 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 2000 VL 47 IS 5 BP 915 EP 921 DI 10.1109/16.841221 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 314WZ UT WOS:000087081700003 ER PT J AU Rohatgi, A Doshi, P Moschner, J Lauinger, T Aberle, AG Ruby, DS AF Rohatgi, A Doshi, P Moschner, J Lauinger, T Aberle, AG Ruby, DS TI Comprehensive study of rapid, low-cost silicon surface passivation technologies SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE passivation; rapid thermal oxide; silicon; silicon nitride; suface; solar cells ID SOLAR-CELLS AB A comprehensive and systematic investigation of low-cost surface passivation technologies is presented for achieving high-performance silicon devices such as solar cells. Most commercial solar cells today lack adequate surface passivation, while laboratory cells use conventional furnace oxides (CFO) for high-quality surface passivation involving an expensive and lengthy high-temperature step. This investigation tries to bridge the gap between commercial and laboratory cells by providing fast, low-cost methods for effective surface passivation. This paper demonstrates for the first time, the efficacy of TiO2, thin (<10 nm) rapid thermal oxide (RTO), and PECVD SIN individually and in combination for (phosphorus diffused) emitter and (undiffused) back surface passivation. The effects of emitter sheet resistance, surface texture, and three different SIN depositions (two direct PECVD systems and one remote plasma system) were investigated. The effects of post-growth/deposition treatments such as forming gas anneal (FGA) and firing of screen-printed contacts were also examined. This study reveals that the optimum passivation scheme consisting of a thin RTO with a SiN cap followed by a very short 730 degrees C anneal can 1) reduce the emitter saturation current density, J(0e), by a factor of >15 for a 90 Omega/sq emitter, 2) reduce J0(e) by a factor of >3 for a 40 Omega/sq emitter, and 3) reduce S-back below 20 cm/s on 1.3 Omega p-Si. Furthermore, this double-layer RTO+SiN passivation is relatively independent of the deposition conditions (direct or remote) of the SiN film and is more stable under heat treatment than SiN or RTO alone. Model calculations are also performed to show that the RTO+SiN surface passivation scheme may lead to 17%-efficient thin screen-printed cells even with a low bulk lifetime of 20 mu S. C1 Univ Ctr Excellence Photovoltaics Res & Educ, Sch Elect & Comp Engn, Georgia Inst Technol, Atlanta, GA 30332 USA. Hewlett Packard Co, Atlanta, GA 30319 USA. Inst Solarenergieforsch GMBH, D-31860 Emmerthal, Germany. Univ New S Wales, Photovoltaics Special Res Ctr, Sydney, NSW 2052, Australia. Sandia Natl Labs, Albuquerque, NM 87185 USA. RP Rohatgi, A (reprint author), Univ Ctr Excellence Photovoltaics Res & Educ, Sch Elect & Comp Engn, Georgia Inst Technol, Atlanta, GA 30332 USA. NR 22 TC 47 Z9 48 U1 4 U2 21 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD MAY PY 2000 VL 47 IS 5 BP 987 EP 993 DI 10.1109/16.841230 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 314WZ UT WOS:000087081700012 ER PT J AU Walthall, CL Halthore, RN Loechel, SE Elman, GC Markham, BL AF Walthall, CL Halthore, RN Loechel, SE Elman, GC Markham, BL TI Measuring aerosol optical thickness with a helicopter-based sunphotometer SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosol optcal thickness; airborne measurements; helicopters; sun photometer ID REFLECTANCES; PLATFORM AB The use of airborne sunphotometers and radiometrically calibrated sensors with fixed wing remote sensing platforms is a reliable method for obtaining atmospherically corrected surface reflectance. Here we describe a variation of such an instrument for use with helicopters. This system tracks the sun once positioned within 30 degrees of the solar disk. The electronics sample fast enough to collect data between passes of the rotor blades. Calibration for converting voltages to atmospheric transmittance was via the Langley plot method and by intercomparison with calibrated surface sunphotometers, Aerosol optical thickness can be inferred at discrete wavelengths in the visible and near-infrared portions of the spectrum. Aerosol optical thickness data collected with the system agrees reasonably well with data collected using other surface-based sunphotometers. C1 USDA ARS, Remote Sensing & Modeling Lab, Beltsville, MD 20705 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Univ Maryland, Dept Geog, Lab Global Remote Sensing Studies, College Pk, MD 20742 USA. Corvis Corp, Columbus, MD 21046 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Walthall, CL (reprint author), USDA ARS, Remote Sensing & Modeling Lab, Beltsville, MD 20705 USA. RI Markham, Brian/M-4842-2013 OI Markham, Brian/0000-0002-9612-8169 NR 16 TC 1 Z9 1 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2000 VL 38 IS 3 BP 1410 EP 1416 DI 10.1109/36.843035 PG 7 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 320EM UT WOS:000087388900029 ER PT J AU Ashikhmin, AE Barg, AM Knill, E Litsyn, SN AF Ashikhmin, AE Barg, AM Knill, E Litsyn, SN TI Quantum error detection I: Statement of the problem SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE measurement; quantum code; Shor-Laflamme enumerators; undetected error ID CORRECTING CODES; ENUMERATORS AB This paper is devoted to the problem of error detection with quantum codes. We show that it is possible to give a consistent definition of the undetected error event. To prove this, me examine possible problem settings for quantum error detection, Our goal is to derive a functional that describes the probability: of undetected error under natural physical assumptions concerning transmission with error detection with quantum codes, We discuss possible transmission protocols with stabilizer and unrestricted quantum codes. The set of results proved in the paper shows that in all the cases considered the average probability of undetected error for a given code is essentially given by one and the same function of its weight enumerators. In the final section of the paper we examine polynomial invariants of quantum codes and show that coefficients of Rains's "unitary weight enumerators" [17] are known for classical codes under the name of binomial moments of the distance distribution. As in the classical situation, these enumerators provide an alternative expression for the probability of undetected error. In a companion paper (part II) we use the relation of the probability of undetected error and weight enumerators to derive bounds on this probability for quantum codes. C1 Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Univ Calif Los Alamos Natl Lab, Grp CIC3, Los Alamos, NM 87545 USA. Tel Aviv Univ, Dept Elect Engn Syst, IL-69978 Tel Aviv, Israel. RP Ashikhmin, AE (reprint author), Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. NR 20 TC 16 Z9 17 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD MAY PY 2000 VL 46 IS 3 BP 778 EP 788 DI 10.1109/18.841162 PG 11 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 311NR UT WOS:000086890900003 ER PT J AU Ashikhmin, AE Barg, AM Knill, E Litsyn, SN AF Ashikhmin, AE Barg, AM Knill, E Litsyn, SN TI Quantum error detection II: Bounds SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article DE polynomial method; probability of undetected error; quantum code; self-orthogonal codes ID CODES AB In Part I of this paper we formulated the problem of error detection with quantum codes on the depolarizing channel and gave an expression for the probability of undetected error via the weight enumerators of the code. In this part we show that there exist quantum codes whose probability of undetected error falls exponentially with the length of the code and derive bounds on this exponent, The lower (existence) bound is proved for stabilizer codes by a counting argument for classical self-orthogonal quaternary codes. Upper bounds are proved by linear programming. First we formulate two linear programming problems that are convenient for the analysis of specific short codes, Next we give a relaxed formulation of the problem in terms of optimization on the cone of polynomials in the Krawtchouk basis. We present two general solutions of the problem, Together they give an upper bound on the exponent of undetected error, The upper and lower asymptotic bounds coincide for a cel tain interval of code rates close to 1. C1 Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Univ Calif Los Alamos Natl Lab, Grp CIC3, Los Alamos, NM 87545 USA. Tel Aviv Univ, Dept Elect Engn Syst, IL-69978 Tel Aviv, Israel. RP Ashikhmin, AE (reprint author), Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. NR 15 TC 16 Z9 16 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9448 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD MAY PY 2000 VL 46 IS 3 BP 789 EP 800 DI 10.1109/18.841163 PG 12 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 311NR UT WOS:000086890900004 ER PT J AU Reutter, BW Gullberg, GT Huesman, RH AF Reutter, BW Gullberg, GT Huesman, RH TI Direct least-squares estimation of spatiotemporal distributions from dynamic SPECT projections using a spatial segmentation and temporal B-splines SO IEEE TRANSACTIONS ON MEDICAL IMAGING LA English DT Article DE dynamic single photon emission computed tomography (SPECT); fully four-dimensional (4-D) reconstruction; kinetic parameter estimation ID EMISSION COMPUTED-TOMOGRAPHY; KINETIC PARAMETER-ESTIMATION; OF-INTEREST EVALUATION; MODEL-BASED ESTIMATION; PET; RECONSTRUCTION; ALGORITHM AB Artifacts can result when reconstructing a dynamic image sequence from inconsistent, as well as insufficient and truncated, cone beam single photon emission computed tomography (SPECT) projection data acquired by a slowly rotating gantry, The artifacts can lead to biases in kinetic model parameters estimated from time-activity curves generated by overlaying volumes of interest on the images. However, the biases in time-activity curve estimates and subsequent kinetic parameter estimates can be reduced significantly by first modeling the spatial and temporal distribution of the radiopharmaceutical throughout the projected field of view, and then estimating the time-activity curves directly from the projections. This approach is potentially useful for clinical SPECT studies involving slowly rotating gantries, particularly those using a single-detector system or body contouring orbits with a multidetector system. We have implemented computationally efficient methods for fully four-dimensional (4-D) direct estimation of spatiotemporal distributions from dynamic SPECT projection data, Temporal B-splines providing various orders of temporal continuity, as well as various time samplings, were used to model the time-activity curves for segmented blood pool and tissue volumes in simulated cone beam and parallel beam cardiac data acquisitions. Least-squares estimates of time-activity curves were obtained quickly using a workstation. Given faithful spatial modeling, accurate curve estimates were obtained using cubic, quadratic, or linear B-splines and a relatively rapid time sampling during initial tracer uptake. From these curves, kinetic parameters were estimated accurately for noiseless data and with some bias for noisy data, A preliminary study of spatial segmentation errors showed that spatial model mismatch adversely affected quantitative accuracy, but also resulted in structured errors (projected model versus raw data) that were easily detected in our simulations. This suggests iterative refinement of the spatial model to reduce structured errors as an area of future research. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. Univ Utah, Dept Radiol, Med Imaging Res Lab, Salt Lake City, UT 84132 USA. RP Reutter, BW (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. EM bwreutter@lbl.gov FU NHLBI NIH HHS [P01-HL25840, R01-HL50663] NR 33 TC 60 Z9 60 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0278-0062 J9 IEEE T MED IMAGING JI IEEE Trans. Med. Imaging PD MAY PY 2000 VL 19 IS 5 BP 434 EP 450 DI 10.1109/42.870254 PG 17 WC Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Engineering, Electrical & Electronic; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging SC Computer Science; Engineering; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging GA 359NP UT WOS:000089617200009 PM 11021687 ER PT J AU Qi, JY Leahy, RM AF Qi, JY Leahy, RM TI Resolution and noise properties of MAP reconstruction for fully 3-D PET SO IEEE TRANSACTIONS ON MEDICAL IMAGING LA English DT Article DE covariance; fully 3-D PET; image reconstruction; MAP estimation; positron emission tomography; resolution analysis; uniform resolution ID BAYESIAN IMAGE-RECONSTRUCTION; EMISSION TOMOGRAPHY; EM ALGORITHM; VARIANCE; MICROPET; SCANNER AB We derive approximate analytical expressions for the local impulse response and covariance of images reconstructed from fully three-dimensional (3-D) positron emission tomography (PET) data using maximum a posteriori (MAP) estimation. These expressions explicitly account for the spatially variant detector response and sensitivity of a 3-D tomograph, The resulting spatially variant impulse response and covariance are computed using 3-D Fourier transforms. A truncated Gaussian distribution is used to account for the effect on the variance of the nonnegativity constraint used in MAP reconstruction. Using Monte Carlo simulations and phantom data from the microPET small animal scanner, we show that the approximations provide reasonably accurate estimates of contrast recovery and covariance of MAP reconstruction for priors with quadratic energy functions. We also describe how these analytical results can be used to achieve near-uniform contrast recovery throughout the reconstructed volume. C1 Univ So Calif, Inst Signal & Image Proc, Los Angeles, CA 90089 USA. RP Qi, JY (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. RI Qi, Jinyi/A-1768-2010 OI Qi, Jinyi/0000-0002-5428-0322 FU NCI NIH HHS [R01 CA59794]; NHLBI NIH HHS [P01 HL25840] NR 22 TC 231 Z9 231 U1 2 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0278-0062 J9 IEEE T MED IMAGING JI IEEE Trans. Med. Imaging PD MAY PY 2000 VL 19 IS 5 BP 493 EP 506 DI 10.1109/42.870259 PG 14 WC Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Engineering, Electrical & Electronic; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging SC Computer Science; Engineering; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging GA 359NP UT WOS:000089617200014 PM 11021692 ER PT J AU Huesman, RH Klein, GJ Moses, WW Qi, JY Reutter, BW Virador, PRG AF Huesman, RH Klein, GJ Moses, WW Qi, JY Reutter, BW Virador, PRG TI List-mode maximum-likelihood reconstruction applied to positron emission mammography (PEM) with irregular sampling SO IEEE TRANSACTIONS ON MEDICAL IMAGING LA English DT Article DE image reconstruction; list-mode likelihood; mammography; positron emission tomography ID EM ALGORITHM; STATISTICS AB We present a preliminary study of list-mode likelihood reconstruction of images for a rectangular positron emission tomograph (PET) specifically designed to image the human breast. The prospective device consists of small arrays of scintillation crystals for which depth of interaction is estimated. Except in very rare instances, the number of annihilation events detected is expected to be far less than the number of distinguishable events, If one were to histogram the acquired data, most histogram bins would remain vacant. Therefore, it seems natural to investigate the efficacy of processing events one at a time rather than processing the data in histogram format. From a reconstruction perspective, the new tomograph presents a challenge in that the rectangular geometry leads to irregular radial and angular sampling, and the field of view extends completely to the detector faces. Simulations are presented that indicate that the proposed tomograph can detect 8-mm-diameter spherical tumors with a tumor-to-background tracer density ratio of 3 : 1 using realistic image acquisition parameters. Spherical tumors of 4-mm diameter are near the limit of detectability with the image acquisition parameters used. Expressions are presented to estimate the loss of image contrast due to Compton scattering. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. RP Huesman, RH (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Funct Imaging, Berkeley, CA 94720 USA. RI Qi, Jinyi/A-1768-2010 OI Qi, Jinyi/0000-0002-5428-0322 FU NCI NIH HHS [R01-CA67911]; NHLBI NIH HHS [P01-HL25840] NR 11 TC 103 Z9 104 U1 1 U2 11 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0278-0062 J9 IEEE T MED IMAGING JI IEEE Trans. Med. Imaging PD MAY PY 2000 VL 19 IS 5 BP 532 EP 537 DI 10.1109/42.870263 PG 6 WC Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Engineering, Electrical & Electronic; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging SC Computer Science; Engineering; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging GA 359NP UT WOS:000089617200018 PM 11021696 ER PT J AU Tsap, LV Goldgof, DB Sarkar, S AF Tsap, LV Goldgof, DB Sarkar, S TI Nonrigid motion analysis based on dynamic refinement of finite element models SO IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE LA English DT Article DE physically-based vision; deformable models; nonrigid motion analysis; biomedical applications; finite element analysis ID INTERFACE; IMAGES AB In this paper, we propose new algorithms for accurate nonrigid motion tracking. Given an initial model representing general knowledge of the object, a set of sparse correspondences, and incomplete or missing information about geometry or material properties, we can recover dense motion vectors using finite element models. The method is based on the iterative analysis of the differences between the actual and predicted behavior. Large differences indicate that an object's properties are not captured properly by the model describing it. Feedback from the images during the motion allows the refinement of the model by minimizing the error between the expected and true position of the object's points. These errors are due to flaws in the model parameter estimation such as geometry and material properties. Unknown parameters are recovered using an iterative descent search for the best nonlinear finite element model that approximates nonrigid motion of the given object. During this search process, we not only estimate material properties. but also infer dense point correspondences from our initial set of sparse correspondences. Thus, during tracking, the model is refined which, in turn, improves tracking quality. As a result, we obtain a more precise description of nonrigid motion. Experimental results demonstrate the success of the proposed algorithm. The method was applied to man-made elastic materials and human skin to recover unknown elasticity. to complex 3D objects to find details of their geometry, and to a hand motion analysis application. Our work demonstrates the possibility of accurate quantitative analysis of nonrigid motion in range image sequences with objects consisting of multiple materials and 3D volumes. C1 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. Univ S Florida, Dept Comp Sci & Engn, Tampa, FL 33620 USA. RP Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Livermore, CA 94551 USA. EM tsap1@llnl.gov; goldgof@bigpine.csee.usf.edu; sarkar@bigpine.csee.usf.edu RI Sarkar, Sudeep/A-8213-2009 OI Sarkar, Sudeep/0000-0001-7332-4207 NR 37 TC 43 Z9 46 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0162-8828 EI 1939-3539 J9 IEEE T PATTERN ANAL JI IEEE Trans. Pattern Anal. Mach. Intell. PD MAY PY 2000 VL 22 IS 5 BP 526 EP 543 DI 10.1109/34.857007 PG 18 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 337FV UT WOS:000088347500008 ER PT J AU Kavicky, JA Shahidehpour, SM AF Kavicky, JA Shahidehpour, SM TI A subarea-level transaction simulation framework supporting parallel paths and energy tagging SO IEEE TRANSACTIONS ON POWER SYSTEMS LA English DT Article DE power system operations; transmission modeling; parallel paths; distribution factors; energy tagging; linear programming ID ECONOMY AB A methodology is proposed to improve transaction modeling for electrical systems, and associated expense estimation, by applying a transmission constraint data reduction technique and a novel transmission model formulation, A linear programming model is described, which represents parallel flows and manages transaction tagging and accounting to improve model optimality and treatment of nonlinear phenomena, The modeling framework is a large-scale approach that provides screening results to initiate detailed small-scale investigations, The methodology also supplements the flow-based transmission modeling philosophy currently under consideration by the North American Electric Reliability Council (NERC), The proposed method extends the NERC utility-level model to a subarea-level network model to improve overall transmission modeling detail and performance. In addition, the model merges an optimizing technique with the parallel path and energy tagging features into one homogeneous model. C1 Argonne Natl Lab, Dept Informat & Decis Sci, Argonne, IL 60439 USA. IIT, Dept Elect & Comp Engn, Chicago, IL 60616 USA. RP Kavicky, JA (reprint author), Argonne Natl Lab, Dept Informat & Decis Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. NR 10 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-8950 J9 IEEE T POWER SYST JI IEEE Trans. Power Syst. PD MAY PY 2000 VL 15 IS 2 BP 873 EP 878 DI 10.1109/59.867187 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 352TJ UT WOS:000089233700062 ER PT J AU Lee, JD Sanquist, TF AF Lee, JD Sanquist, TF TI Augmenting the operator function model with cognitive operations: Assessing the cognitive demands of technological innovation in ship navigation SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART A-SYSTEMS AND HUMANS LA English DT Article DE automation; cognitive risk analysis; failure analysis; operator function model navigation ID SUPERVISORY CONTROL-SYSTEMS; COCKPIT REMEMBERS; DESIGN AB The increasing technological sophistication of ship navigation systems may significantly alter the skills, knowledge, and strategies involved in navigating large ships. Many examples in other domains illustrate the dangers of technology-driven innovations. These examples show that without a systematic method to detect design flaws and training requirements, technology-driven designs may degrade rather than enhance maritime safety. The operator function model (OFM) provides the basis for examining technological innovations; however, the OFM does not describe specific cognitive demands. Augmenting the OFM with a description of cognitive operations provides a structured cognitive task analysis tool-OFM-COG-that can identify the design and training requirements needed to safeguard system performance. This approach identifies how to tailor designs, develop training, and adjust qualifications to minimize the human errors that might otherwise accompany technological innovation. This paper shows how OFM-COG can catalog differences between traditional navigation systems and those augmented with electronic charts and collision avoidance systems, Specifically, it examines the cognitive demands of collision avoidance and track keeping, with and without advanced technological aids. This analysis demonstrates that some advanced radars may in fact increase the likelihood of certain collisions, and that the current certification process does not reflect the cognitive demands of the new technology. The analysis also indicates that electronic chart display and information systems (ECDIS) can reduce the redundancy that has served to make traditional systems quite reliable, Drawing upon these examples, this paper describes OFM-COG and demonstrates how this novel, model-based analysis technique can document the cognitive implications of technological innovations. C1 Univ Iowa, Dept Ind Engn, Iowa City, IA 52242 USA. Battelle Seattle Res Ctr, Seattle, WA 98105 USA. RP Lee, JD (reprint author), Univ Iowa, Dept Ind Engn, Iowa City, IA 52242 USA. RI Lee, John/A-9774-2009; Lee, John/E-9987-2010 OI Lee, John/0000-0001-9808-2160 NR 46 TC 26 Z9 26 U1 2 U2 10 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1083-4427 J9 IEEE T SYST MAN CY A JI IEEE Trans. Syst. Man Cybern. Paart A-Syst. Hum. PD MAY PY 2000 VL 30 IS 3 BP 273 EP 285 DI 10.1109/3468.844353 PG 13 WC Computer Science, Cybernetics; Computer Science, Theory & Methods SC Computer Science GA 321AH UT WOS:000087432400004 ER PT J AU Besmann, TM Stinton, DP Lowden, RA Probst, KJ Anderson, TJ AF Besmann, TM Stinton, DP Lowden, RA Probst, KJ Anderson, TJ TI Near-net-shape fabrication by forced-flow, thermal gradient CVI SO INDUSTRIAL CERAMICS LA English DT Article ID DEPOSITION AB Forced-flow thermal gradient chemical vapor infiltration (FCVI) has been developed fbr the rapid densification of ceramic matrix composites. For preforms of >3 mm thickness FCVI can produce a near-net-shape part in less than one day as opposed to isothermal, isobaric CVI which requires several weeks to density such a component. Efforts at ORNL and elsewhere have resulted in capability to produce prototypical thick-walled heat exchanger tubes and turbine disk blanks. This paper will review recent modeling and experimental efforts re fated to the FCVI of cylindrical forms. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN USA. Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU TECHNA SRL PI FAENZA PA PO BOX 174, 48018 FAENZA, ITALY SN 1121-7588 J9 IND CERAM JI Ind. Ceram. PD MAY-AUG PY 2000 VL 20 IS 2 BP 112 EP 115 PG 4 WC Materials Science, Ceramics SC Materials Science GA 373GZ UT WOS:000165282100011 ER PT J AU Bishop, RL Harradine, DM Flesner, RL Larson, SA Bell, DA AF Bishop, RL Harradine, DM Flesner, RL Larson, SA Bell, DA TI Safe operating temperatures for pressurized alkaline hydrolysis of HMX-based explosives SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID PLASTIC-BONDED EXPLOSIVES; HEAT AB Alkaline hydrolysis is used to convert high explosives to nonenergetic, aqueous compounds. Base hydrolysis of high explosives is exothermic (Delta H-RXN = 2.3 kJ/g), and thermal runaway of the reaction is a possibility at elevated temperatures (>120 degrees C) where the rate of reaction is large. Thermal runaway could result in an accidental detonation of the energetic material being treated, so safe operating parameters for base hydrolysis need to be determined. To measure the safe operating temperature, base hydrolysis was performed at temperatures ramped from 20 to 300 degrees C. The results show that PBX 9501 molding powder detonates at a 185 degrees C bulk temperature in 1.5 hi NaOH with a 4.5 degrees C/min linear temperature ramp and no agitation. The reaction of pressed PBX 9501 with 0.75, 1.5, and 3.0 M NaOH and water and both pressed and nonpressed PBX 9404 with 0.75, 1.5 M, and 3.0 M NaOH and water aid not produce a detonation with a 4.5 degrees C/min linear temperature ramp. A previously developed reaction rate model was used to show that thermal runaway should occur when the base hydrolysis reaction rate reached a maximum at a bulk temperature between 185 and 225 degrees C. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wyoming, Dept Chem & Petr Engn, Laramie, WY 82071 USA. RP Bell, DA (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663,MS C920, Los Alamos, NM 87545 USA. NR 39 TC 4 Z9 4 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD MAY PY 2000 VL 39 IS 5 BP 1215 EP 1220 DI 10.1021/ie9904448 PG 6 WC Engineering, Chemical SC Engineering GA 311NA UT WOS:000086889300014 ER PT J AU Borbely, AM AF Borbely, AM TI Digital process equipment not keen on dirty power SO INTECH LA English DT Article C1 Pacific NW Lab, Richland, WA 99352 USA. RP Borbely, AM (reprint author), Pacific NW Lab, Richland, WA 99352 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INSTRUMENT SOC AMER PI RES TRIANGLE PK PA 67 ALEXANDER DRIVE, RES TRIANGLE PK, NC 27709 USA SN 0192-303X J9 INTECH JI Intech PD MAY PY 2000 VL 47 IS 5 BP 54 EP 56 PG 3 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 312JT UT WOS:000086940700018 ER PT J AU Fleck, NA Liu, D Shu, JY AF Fleck, NA Liu, D Shu, JY TI Microbuckle initiation from a hole and from the free edge of a fibre composite SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article ID KINK BAND FORMATION; FIBER COMPOSITES; COMPRESSIVE FAILURE; PREDICTION; STRENGTH AB Microbuckle initiation from an open hole, from a filled hole, and from the free surface of a unidirectional fibre composite is examined by a finite element method. The role of fibre bending resistance is included in the formulation so that a hole size effect is predicted. It is found that the open hole knocks-down the compressive strength to the order of 20 tau(Y), while the filled hole reduces the strength to about 40 tau(Y), where tau(Y) is the in-plane shear modulus of the composite. Pre-existing fibre waviness adjacent to the hole gives a further reduction in the compressive strength. The role of in-plane shear stress and transverse stress in reducing the open hole compressive strength is examined: the compressive strength is reduced by the presence of shear and transverse tension, but the effect is less pronounced than that observed previously for the case of a circular patch of waviness. The study concludes with an investigation of the influence of the free surface on microbuckle initiation from a band of waviness and from a semi-circular patch of waviness a negligible effect of the free surface on the compressive strength is predicted. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Cambridge, Dept Engn, Cambridge CB2 1PZ, England. Univ Calif Lawrence Livermore Natl Lab, Dept Chem & Mat Sci, Livermore, CA 94550 USA. RP Fleck, NA (reprint author), Univ Cambridge, Dept Engn, Trumpington St, Cambridge CB2 1PZ, England. NR 28 TC 3 Z9 3 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD MAY PY 2000 VL 37 IS 20 BP 2757 EP 2775 DI 10.1016/S0020-7683(99)00041-4 PG 19 WC Mechanics SC Mechanics GA 289LC UT WOS:000085621600001 ER EF