FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Pardavi-Horvath, M Keszei, B Vandlik, J McMichael, RD AF Pardavi-Horvath, M Keszei, B Vandlik, J McMichael, RD TI Ferromagnetic resonance spectra of thick yttrium-iron-garnet films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc AB Due to the finite aspect ratio of the ferrite, the distribution of the internal field in small planar microwave ferrite devices is strongly inhomogeneous. This is a source of additional losses through magnetostatic modes. To study the magnetostatic modes, the thickness dependence of the ferromagnetic resonance spectra was measured for a series of 2 mm square single crystal yttrium-iron-garnet films in the 35 < h < 220 mu m thickness range. The in-plane resonance field H-r increases with thickness by 150 G, while H-r normal to film plane decreases. The uniform mode linewidth, dH(r) is in the 2-20 G range. A large number of magnetostatic wave modes modes is excited, covering the "full spectral width," DH, increasing with thickness from 400 to 960 G. In a ferrite device DH has to be taken into account, giving rise to large losses in spite of the small intrinsic linewidth dH(r) of the material. (C) 2000 American Institute of Physics. [S0021- 8979(00)25808-8]. C1 George Washington Univ, Dept ECE, Washington, DC 20052 USA. Res Inst Tech Phys & Mat Sci, H-1525 Budapest, Hungary. NIST, Div Met, Gaithersburg, MD 20899 USA. RP Pardavi-Horvath, M (reprint author), George Washington Univ, Dept ECE, Washington, DC 20052 USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 10 TC 7 Z9 7 U1 0 U2 5 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 1 PY 2000 VL 87 IS 9 BP 4969 EP 4971 DI 10.1063/1.373218 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200100 ER PT J AU Liu, K Zhou, SM Chien, CL Nikitenko, VI Gornakov, VS Shapiro, AJ Shull, RD AF Liu, K Zhou, SM Chien, CL Nikitenko, VI Gornakov, VS Shapiro, AJ Shull, RD TI Anisotropy-dependent macroscopic domain structure in wedged-permalloy/uniform-FeMn bilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID EXCHANGE BIAS; THIN-FILMS; MODEL; MAGNETORESISTANCE; INTERFACES AB Macroscopic domain structures have been realized in wedged-permalloy (Py)/uniform-FeMn bilayers during magnetization reversal. When the exchange anisotropy is established perpendicular or parallel to the wedge direction, two macroscopic domains are observed. Separating these domains are a 180 degrees wall in the perpendicular geometry and an intermediate band containing large density of stripe-type microdomains in the parallel geometry. While the exchange field remains practically the same in both geometries, the coercivity and squareness of the loop are much less in the parallel geometry. (C) 2000 American Institute of Physics. [S0021-8979(00)59208-1]. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NIST, Div Met, Gaithersburg, MD 20899 USA. Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Russia. RP Liu, K (reprint author), Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RI Liu, Kai/B-1163-2008; Shull, Robert/F-5971-2013 OI Liu, Kai/0000-0001-9413-6782; NR 21 TC 7 Z9 7 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 1 PY 2000 VL 87 IS 9 BP 5052 EP 5054 DI 10.1063/1.373245 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200127 ER PT J AU Lu, RP Morgan, BA Kavanagh, KL Powell, CJ Chen, PJ Serpa, FG Egelhoff, WF AF Lu, RP Morgan, BA Kavanagh, KL Powell, CJ Chen, PJ Serpa, FG Egelhoff, WF TI Hot-electron attenuation lengths in ultrathin magnetic films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID SCHOTTKY-BARRIER HEIGHT; EMISSION-MICROSCOPY; GIANT MAGNETORESISTANCE; SCATTERING PROCESSES; ELASTIC-SCATTERING; CARRIER TRANSPORT; INTERFACES; METAL; SPECTROSCOPY; TRANSMISSION AB Ballistic electron emission microscopy (BEEM) is used to measure hot-electron transport across magnetic metal multilayers. Room temperature measurements in air have been carried out on Au/M/Si(100), Au/M/Au/Si(100), and Au/M/PtSi/Si diodes, that were sputter deposited at 175 or 300 K, where M is Co, Fe, Ni, Cu, or Ni81Fe19. Plots of log BEEM current versus M thickness are linear giving hot-electron (1.5 eV) attenuation lengths (ALs), for Au/M/Si diodes (M=Co, Fe, Ni81Fe19, and Ni) of 0.3, 0.5, 0.8, and 1.3 nm, respectively (with typical standard uncertainties of +/- 10%). Magnetic metal sandwich diodes, (Au/M/Au/Si) show larger ALs, 0.8 and 2.1 nm, for M=Co and Ni81Fe19, respectively. PtSi interlayers improve the surface roughness but have little effect on the AL while low temperature depositions increase the AL. We presume that the increases in the AL are due to better microstructure, less silicide reaction, or to changes in elastic scattering at interfaces. (C) 2000 American Institute of Physics. [S0021-8979(00)71608-2]. C1 Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Lu, RP (reprint author), Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RI Kavanagh, Karen/J-6914-2012; OI Kavanagh, Karen/0000-0002-3059-7528 NR 30 TC 23 Z9 23 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 1 PY 2000 VL 87 IS 9 BP 5164 EP 5166 DI 10.1063/1.373417 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200165 ER PT J AU Schreyer, A Schmitte, T Siebrecht, R Bodeker, P Zabel, H Lee, SH Erwin, RW Majkrzak, CF Kwo, J Hong, M AF Schreyer, A Schmitte, T Siebrecht, R Bodeker, P Zabel, H Lee, SH Erwin, RW Majkrzak, CF Kwo, J Hong, M TI Neutron scattering on magnetic thin films: Pushing the limits (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID SPIN-DENSITY WAVES; COUPLED FE/CR(001) SUPERLATTICES; CR; LAYERS; ANTIFERROMAGNETISM; REORIENTATION; CHROMIUM AB Neutron scattering has been the scattering technique of choice for the analysis of magnetic structures and their dynamics for many decades. The advent of magnetic thin film systems has posed new challenges since such samples have inherently small scattering volumes. By way of examples, recent progress in the application of neutron scattering for the study of both magnetic structure and dynamics in magnetic thin film systems will be presented. First, a combined high angle neutron scattering and polarized neutron reflectivity investigation of the magnetic order of Cr and its influence on the exchange coupling between the Fe layers in Fe/Cr superlattices is discussed. It is shown that in the whole thickness range up to 3000 Angstrom, the magnetic structure is governed by frustration effects at the Fe/Cr interfaces. Second, it is demonstrated that it is now possible to investigate the dynamic properties of magnetic thin films with neutron scattering. Unlike, e.g., Brillouin light scattering, inelastic neutron scattering provides access to large portions of the Brillouin zone. First results on spin wave excitations in a Dy/Y superlattice are presented. (C) 2000 American Institute of Physics. [S0021-8979(00)92908-6]. C1 Ruhr Univ Bochum, Inst Phys Expt Festkorperphys, D-44780 Bochum, Germany. NIST, Gaithersburg, MD 20899 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Schreyer, A (reprint author), Ruhr Univ Bochum, Inst Phys Expt Festkorperphys, D-44780 Bochum, Germany. RI Hong, Minghwei/C-1433-2010; Zabel, Hartmut/C-1994-2009 NR 33 TC 27 Z9 27 U1 0 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 5443 EP 5448 DI 10.1063/1.373367 PN 2 PG 6 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200250 ER PT J AU Arnold, CS Pappas, DP Popov, AP AF Arnold, CS Pappas, DP Popov, AP TI Magneto-optic Kerr effect study of a two-step reorientation transition of an ultrathin magnetic film SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID SUSCEPTIBILITY MEASUREMENTS; THICKNESS-DRIVEN; ANISOTROPY; ORDER; FE AB The magnetic reorientation transition for ultrathin Fe films on Gd is studied. At low temperatures, the films are magnetized in plane and at intermediate temperatures they undergo a reorientation to out of plane. The reorientation is attributed to the reducing magnetization of Gd as it approaches its Curie temperature and the perpendicular magnetic anisotropy at the Fe surface. Detailed measurements of the reorientation were made in situ using the magneto-optic Kerr effect (MOKE). The first step, at low temperature, is a continuous, reversible reorientation of the surface moment from in plane to canted out of plane; a corresponding peak in the susceptibility identifies it as a second-order phase transition. The second step is a discontinuous, irreversible rotation from this canted direction to perpendicular to the film plane; thermal hysteresis of the magnetization identifies it as a first-order phase transition. The MOKE thermal hysteresis loop shows that the Gd surface region participates in the first-order phase transition. (C) 2000 American Institute of Physics. [S0021-8979(00)31508-0]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Moscow State Engn Phys Inst, Moscow, Russia. RP Arnold, CS (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 7 Z9 7 U1 1 U2 2 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 1 PY 2000 VL 87 IS 9 BP 5478 EP 5480 DI 10.1063/1.373378 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200261 ER PT J AU Donahue, MJ Porter, DG McMichael, RD Eicke, J AF Donahue, MJ Porter, DG McMichael, RD Eicke, J TI Behavior of mu MAG standard problem No. 2 in the small particle limit SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID SQUARE GRIDS; FIELD AB For a uniformly magnetized rectangular particle with dimensions in the ratio 5 : 1 : 0.1, the coercive and switching fields in the (1,1,1) direction are determined to be H-c/M-s = 0.057069478 and H-s/M-s = 0.057142805. Previous micromagnetic computations of coercive and switching fields that did not approach these values for small particles are analyzed. It is shown that the disagreement was primarily due to a disparity in the method of calculating demagnetization energy. Corrected simulations are shown to agree with analytically determined values. (C) 2000 American Institute of Physics. [S0021-8979(00)81708-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. RP Donahue, MJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012 NR 8 TC 29 Z9 29 U1 1 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 1 PY 2000 VL 87 IS 9 BP 5520 EP 5522 DI 10.1063/1.373391 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200274 ER PT J AU Swartzendruber, LJ Rugkwamsook, P Bennett, LH Della Torre, E AF Swartzendruber, LJ Rugkwamsook, P Bennett, LH Della Torre, E TI Non-Arrhenius temperature dependence of magnetic after effect SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID VISCOSITY; PARTICLES; BEHAVIOR AB The rate of magnetization change (magnetic after effect) which occurs after the magnetic field applied to a magnetic material is switched suddenly to a new value, is generally assumed to increase when the temperature is increased. Deviation from this temperature behavior, which has been observed in several cases, has been ascribed to changes in pertinent magnetic properties, such as magnetocrystalline anisotropy, activation volume, coercive field, etc., with temperature. We report here on the magnetic after effect temperature dependence of a magnetic recording material with magnetic properties that change very little with temperature over a wide temperature range but which, nevertheless, deviates considerably from a monotonic increase in decay rate with increasing temperature. We postulate that this behavior is explained by replacing the Maxwell-Boltzmann statistics by the Bose-Einstein statistics appropriate for the magnon energy distribution. (C) 2000 American Institute of Physics. [S0021-8979(00)83608-7]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. RP Swartzendruber, LJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 17 TC 4 Z9 4 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 5684 EP 5686 DI 10.1063/1.372489 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200328 ER PT J AU Fry, RA Bennett, LH Della Torre, E Farrow, RFC AF Fry, RA Bennett, LH Della Torre, E Farrow, RFC TI Magneto-optical behavior in Co/Pt ultrathin film multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID BEAM-EPITAXIAL-GROWTH; 111 AXES; SUPERLATTICES; ANISOTROPY AB Magneto-optical Kerr effect measurements performed on (0.3 nm Co/x Pt)(15) multilayers with x = 0.3-2.0 nm showed all samples to exhibit strong perpendicular magnetic anisotropy. Recent work has shown that for compositions near (0.3 nm Co/1.2 nm Pt)(15), both polar Kerr rotation and ellipticity exhibit bimodal reversals in which the major hysteresis loops have two distinct field-dependent steps due to the contributions of two magnetic phases. To better understand this bimodal magnetization phenomenon, Kerr rotation and ellipticity were determined as a function of radial position from the center to the edge of this disk sample. These measurements exhibit a continuous variation from two-step (bimodal) behavior in the center to single-step (unimodal) behavior at the edge. Since these films were deposited via MBE with a heated substrate, it is believed that this phenomenon is related to thermally induced variations in interface effects such as alloying, abruptness, and morphology. (C) 2000 American Institute of Physics. [S0021-8979(00)45308-9]. C1 George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. RP Fry, RA (reprint author), George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. NR 16 TC 9 Z9 9 U1 1 U2 2 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 1 PY 2000 VL 87 IS 9 BP 5765 EP 5767 DI 10.1063/1.372515 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200354 ER PT J AU Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK AF Rosenkranz, S Osborn, R Mitchell, JF Vasiliu-Doloc, L Lynn, JW Sinha, SK TI Low-energy spin-wave excitations in the bilayer manganite La1.2Sr1.8Mn2O7 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID T-C; GIANT MAGNETORESISTANCE; DYNAMICS; LA1.4SR1.6MN2O7; TRANSITION; CRYSTALS; STATE AB Inelastic neutron scattering experiments were performed on a single crystal of the bilayer manganite La1.2Sr1.8Mn2O7. Low-energy spin-wave excitations were observed along the c direction with a maximum energy of similar to 0.5 meV at the zone boundary. The dispersion of these acoustic spin wave modes is modeled by a nearest-neighbor Heisenberg model with an interbilayer exchange interaction between neighboring spins in different bilayers of 0.048(1) meV and an anisotropy gap of Delta = 0.077(3) meV. These results confirm the two-dimensional nature of the spin correlations in the bilayer manganites, with a ratio of the in-plane to interbilayer interaction of similar to 200. The temperature dependence of the energies and intensities of the spin wave excitations are in agreement with our earlier conclusion that the ferromagnetic transition is second order. (C) 2000 American Institute of Physics. [S0021-8979(00)42508-9]. C1 Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Rosenkranz, S (reprint author), Argonne Natl Lab, Div Mat Sci, 9700 S Cass Ave, Argonne, IL 60439 USA. RI Osborn, Raymond/E-8676-2011; Rosenkranz, Stephan/E-4672-2011 OI Osborn, Raymond/0000-0001-9565-3140; Rosenkranz, Stephan/0000-0002-5659-0383 NR 25 TC 17 Z9 17 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 1 PY 2000 VL 87 IS 9 BP 5816 EP 5818 DI 10.1063/1.372532 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200371 ER PT J AU Wu, SY Kuo, CM Wang, HY Li, WH Lee, KC Lynn, JW Liu, RS AF Wu, SY Kuo, CM Wang, HY Li, WH Lee, KC Lynn, JW Liu, RS TI Magnetic structure and spin reorientation of the Mn ions in NdMnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID MAGNETORESISTANCE; MANGANITE; ORDER AB The crystal structure and magnetic ordering of the Mn spins in polycrystalline NdMnO3 have been investigated by means of neutron diffraction and ac magnetic susceptibility measurements. The compound crystallizes into an orthorhombic symmetry of space group Pbnm. Three peaks were observed in the temperature dependence of the in-phase component of the ac susceptibility, chi'(T). Neutron diffraction measurements show that all three peaks observed in chi(')(T) are of magnetic origin, and are associated with the ordering and the reorientation of the Mn spins. Both ferromagnetic and antiferromagnetic couplings between the Mn spins were observed, resulting in a noncollinear magnetic structure. The Mn spins order at T(m)approximate to 75 K, and the moment saturates at similar to 20 K at =2.21 mu(B). (C) 2000 American Institute of Physics. [S0021-8979(00)62308-3]. C1 Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. NIST, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Natl Taiwan Univ, Dept Chem, Taipei 106, Taiwan. RP Wu, SY (reprint author), Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. RI Liu, Ru-Shi/A-6796-2010 OI Liu, Ru-Shi/0000-0002-1291-9052 NR 12 TC 40 Z9 40 U1 3 U2 12 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 5822 EP 5824 DI 10.1063/1.372534 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200373 ER PT J AU Michels, A Weissmuller, J Wiedenmann, A Barker, JG AF Michels, A Weissmuller, J Wiedenmann, A Barker, JG TI Exchange-stiffness constant in cold-worked and nanocrystalline Ni measured by elastic small-angle neutron scattering SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID MAGNETIC MICROSTRUCTURE AB We present a new method for determining the exchange-stiffness constant A of a ferromagnetic bulk material by field-dependent elastic small-angle neutron scattering (SANS). In the limit of high applied magnetic field H, for which the scattering volume is a single magnetic domain and the magnetization is nearly aligned with the direction of the applied field, a combination of micromagnetics theory with neutron scattering formalism suggests closed-form expressions for the differential scattering cross section as a function of the scattering vector and of H. Based on these results it is suggested that the exchange-stiffness constant can be extracted from experimental SANS data recorded as a function of H. At ambient temperature we have applied this method to polycrystalline cold-worked Ni and nanocrystalline electrodeposited Ni, finding exchange-stiffness constants of (8.2 +/- 0.2)x10(-12) and (7.6 +/- 0.3)x10(-12) J/m, respectively. Measurement at 5 K yields a value of (9.2 +/- 0.2)x10(-12) J/m for the nanocrystalline sample, a temperature dependence that agrees qualitatively with data in the literature. In addition to the value of A, the technique supplies information on the spatial structure of the magnetic anisotropy field. (C) 2000 American Institute of Physics. [S0021- 8979(00)16608-3]. C1 Univ Saarlandes, FB Phys 10, D-66041 Saarbrucken, Germany. Forschungszentrum Karlsruhe, Inst Nanotechnol, D-76021 Karlsruhe, Germany. Hahn Meitner Inst Kernforsch Berlin GmbH, D-14109 Berlin, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Michels, A (reprint author), Univ Saarlandes, FB Phys 10, Gebaude 43,Postfach 151150, D-66041 Saarbrucken, Germany. RI Weissmuller, Jorg/C-3967-2009; Michels, Andreas/F-6588-2014 OI Weissmuller, Jorg/0000-0002-8958-4414; NR 10 TC 19 Z9 19 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 1 PY 2000 VL 87 IS 9 BP 5953 EP 5955 DI 10.1063/1.372577 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800021 ER PT J AU Kabos, P Kos, AB Silva, TJ AF Kabos, P Kos, AB Silva, TJ TI Vectorial second-harmonic magneto-optic Kerr effect measurements SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID THIN-FILM STRUCTURES; TRANSVERSE AB A significant modification of an existing experimental technique based on the second-harmonic magneto-optical Kerr effect (SH-MOKE) is introduced. With a p-polarized pumping optical wave incident upon a magnetic film, the transverse component of magnetization causes a change in the second-harmonic generation efficiency of the material and the longitudinal component of the magnetization produces a change in the polarization rotation and/or ellipticity of the second-harmonic signal. This permits simultaneous vectorial measurement of the in-plane magnetization components. Examples of measured hysteresis loops from 50 nm thick permalloy films and procedures for SH-MOKE signal calibration are presented. [S0021-8979(00)17108-7]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Kabos, P (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 10 TC 13 Z9 13 U1 0 U2 8 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 1 PY 2000 VL 87 IS 9 BP 5980 EP 5982 DI 10.1063/1.372586 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800030 ER PT J AU Shull, RD McMichael, RD Swartzendruber, LJ Leigh, SD AF Shull, RD McMichael, RD Swartzendruber, LJ Leigh, SD TI Absolute magnetic moment measurements of nickel spheres SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc AB The preparation and measurement of nickel spheres for use in the calibration of magnetometers are described. The absolute value of the magnetic moment of a set of these spheres near room temperature was measured using the Faraday method. The variations of moment for temperatures near room temperature and for applied fields between 0.3 and 5 T were also determined. [S0021-8979(00)17408-0]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Shull, RD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012; Shull, Robert/F-5971-2013; OI McMichael, Robert/0000-0002-1372-664X NR 9 TC 5 Z9 5 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 1 PY 2000 VL 87 IS 9 BP 5992 EP 5994 DI 10.1063/1.372590 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800034 ER PT J AU Lohndorf, M Moreland, J Kabos, P Rizzo, N AF Lohndorf, M Moreland, J Kabos, P Rizzo, N TI Microcantilever torque magnetometry of thin magnetic films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID CANTILEVER; SILICON AB We have developed a microcantilever torque magnetometer based on a torsion-mode atomic force microscope. Thin magnetic films are deposited directly onto micromachined silicon cantilevers. We have measured hysteresis loops of iron thin films with thicknesses ranging from 1 to 40 nm and total magnetic volumes ranging from 2.2x10(-11) to 8.8x10(-10) cm(3). The magnetic moment sensitivity is estimated to be 1.3x10(-12) A m(2)/Hz(1/2) at room temperature and ambient conditions. We expect that by operating at the cantilever torsion resonance frequency and at higher torque fields sensitivity will be improved by a factor of 100-1000. [S0021- 8979(00)17508-5]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Lohndorf, M (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. NR 18 TC 26 Z9 26 U1 1 U2 8 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 1 PY 2000 VL 87 IS 9 BP 5995 EP 5997 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800035 ER PT J AU Bennett, LH Waterstrat, RM Swartzendruber, LJ Bendersky, LA Brown, HJ Watson, RE AF Bennett, LH Waterstrat, RM Swartzendruber, LJ Bendersky, LA Brown, HJ Watson, RE TI Magnetism and incommensurate waves in Zr-3(Rh1-xPdx)(4) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID ZR; PHASE AB Unique properties of the Zr-3(Rh(1-x)Pdx)(4) alloy system are reported here. Contrary to most metallically bonded systems which are not quick to change magnetic behavior with alloy concentration, this system does. Pure Zr3Rh4 and pure Zr3Pd4 are each nonmagnetic, while in the limited range 0.02 < x < 0.08, there is a substantial increase in paramagnetism, attended by a similarly varying incommensurate density wave. At x=0.04 the system exhibits ferromagnetism and displays some superconductivity at x=0.06. The crystal structure involves disclination lines of Rh atoms, or channels, which are equivalent to those of the superconducting A15 structures and bear resemblances to those of the hard magnets. (C) 2000 American Institute of Physics. [S0021-8979(00)17808-9]. C1 George Washington Univ, Ashburn, VA 20147 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. RP Bennett, LH (reprint author), George Washington Univ, Ashburn, VA 20147 USA. NR 7 TC 4 Z9 4 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 6016 EP 6018 DI 10.1063/1.372598 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800042 ER PT J AU Kaka, S Russek, S AF Kaka, S Russek, S TI Switching in spin-valve devices in response to subnanosecond longitudinal field pulses SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID FILMS AB We have fabricated spin-valve devices in a high-speed test structure that allows subnanosecond pulsed field excitation and high-bandwidth observation of the magnetoresistance response. The switching response varies for low-amplitude field pulses and approaches a consistent fast switch of less than 1 ns for field pulses of higher amplitude. For several pulse widths and amplitudes, the device switches into metastable states. The threshold amplitude of the write-pulse was measured as a function of pulse duration for pulses as small as 250 ps in duration. [S0021-8979(00)55408-5]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Kaka, S (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, 325 Broadway, Boulder, CO 80303 USA. NR 8 TC 12 Z9 12 U1 1 U2 1 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 1 PY 2000 VL 87 IS 9 BP 6391 EP 6393 DI 10.1063/1.372716 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800163 ER PT J AU McMichael, RD Lee, CG Stiles, MD Serpa, FG Chen, PJ Egelhoff, WF AF McMichael, RD Lee, CG Stiles, MD Serpa, FG Chen, PJ Egelhoff, WF TI Exchange bias relaxation in CoO-biased films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID FERROMAGNET-ANTIFERROMAGNET BILAYERS; THIN-FILMS; TEMPERATURE-DEPENDENCE; RESONANCE; NIO; LAYERS AB Because the memory of the bias direction is carried by the antiferromagnetic order in exchange biased films, the stability of the antiferromagnetic order is critical to the existence of the exchange bias field. Ferromagnetic resonance was used to measure the relaxation behavior of polycrystalline CoO films coupled to films of Ni80Fe20, probing the system on the time scale of the experiment, approximate to 10(3) s, and the time scale of the magnetic precession, approximate to 10(-10) s. Unidirectional anisotropy (exchange biasing) and isotropic resonance field shifts are observed at the lowest temperatures. Above the apparent exchange bias blocking temperature, isotropic resonance field shifts persist. At still higher temperatures, diminishing resonance field shifts are accompanied by peaks in the FMR linewidth. The results highlight the effects of varying relaxation rates in the CoO relative to the two experimental time scales. (C) 2000 American Institute of Physics. [S0021-8979(00)85308-6]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Changwon Natl Univ, Dept Met & Sci Mat, Changwon 641773, Kyungnam, South Korea. RP McMichael, RD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012; Stiles, Mark/K-2426-2012; OI Stiles, Mark/0000-0001-8238-4156; McMichael, Robert/0000-0002-1372-664X NR 14 TC 27 Z9 27 U1 1 U2 5 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 1 PY 2000 VL 87 IS 9 BP 6406 EP 6408 DI 10.1063/1.373424 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800168 ER PT J AU Alexander, C Rantschler, J Silva, TJ Kabos, P AF Alexander, C Rantschler, J Silva, TJ Kabos, P TI Frequency- and time-resolved measurements of FeTaN films with longitudinal bias fields SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID THIN-FILMS; MAGNETISM AB The high frequency characteristics of 100 nm FeTaN films have been studied by using both time-resolved inductive techniques and frequency-resolved permeability measurements. Experiments performed as a function of longitudinal bias fields from 120 to 2400 A/m (1.5-30 Oe) showed precessional frequencies from 1.3 to 2.5 GHz, initial permeabilities from 1600 to 500, and damping constants alpha=0.013 to 0.0045. It is illustrated that the magnetization precessional data obtained from the time-resolved inductive technique can be Fourier transformed to the frequency domain to give the real and imaginary components of a permeability spectrum; this spectrum compares well with data obtained from frequency-resolved permeability measurements. It is also demonstrated that accurate values of the damping constant alpha can only be determined from permeameters whose bandwidth is two to three times the ferromagnetic resonance frequency of the material to be measured. (C) 2000 American Institute of Physics. [S0021-8979(00)87808-1]. C1 Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. Univ Alabama, Ctr Mat Informat Technol, Tuscaloosa, AL 35487 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Alexander, C (reprint author), Univ Alabama, Dept Phys & Astron, Tuscaloosa, AL 35487 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 13 TC 33 Z9 33 U1 0 U2 8 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 1 PY 2000 VL 87 IS 9 BP 6633 EP 6635 DI 10.1063/1.372794 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800244 ER PT J AU Unguris, J Tulchinsky, D Kelley, MH Borchers, JA Dura, JA Majkrzak, CF Hsu, SY Loloee, R Pratt, WP Bass, J AF Unguris, J Tulchinsky, D Kelley, MH Borchers, JA Dura, JA Majkrzak, CF Hsu, SY Loloee, R Pratt, WP Bass, J TI Magnetic depth profiling Co/Cu multilayers to investigate magnetoresistance (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID NEUTRON-SCATTERING; X-RAY; SURFACES AB The magnetic microstructure responsible for the metastable high resistance state of weakly coupled, as-prepared [Co(6 nm)/Cu(6 nm)](20) multilayers was analyzed using polarized neutron reflectivity and scanning electron microscopy with polarization analysis (SEMPA). This article focuses and expands on the SEMPA measurements. In multilayer structures such as these, SEMPA can be combined with ion milling to directly image the layer-by-layer magnetization and quantitatively depth profile the interlayer magnetic domain correlations. We found that in the as-prepared Co/Cu multilayer, the domains are about 1 mu m in size and the magnetizations in adjacent layers are almost completely oppositely aligned. The relative magnetoresistance derived from this measured degree of anticorrelation is in agreement with the measured magnetoresistance. (C) 2000 American Institute of Physics. [S0021-8979(00)20208-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Fundamental Mat Res, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Sensor Mat, E Lansing, MI 48824 USA. RP Unguris, J (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Dura, Joseph/B-8452-2008; Unguris, John/J-3989-2014 OI Dura, Joseph/0000-0001-6877-959X; NR 15 TC 5 Z9 5 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 1 PY 2000 VL 87 IS 9 BP 6639 EP 6643 DI 10.1063/1.372796 PN 3 PG 5 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800246 ER PT J AU Bae, S Judy, JH Egelhoff, WF Chen, PJ AF Bae, S Judy, JH Egelhoff, WF Chen, PJ TI Dependence of exchange coupling on the surface roughness and structure in alpha-Fe2O3/NiFe and NiFe/alpha-Fe2O3 bilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID MAGNETORESISTANCE AB The exchange coupling characteristics for both Si/alpha-Fe2O3/NiFe and Si/NiFe/alpha-Fe2O3 bilayers have been investigated. These two bilayers showed completely different exchange coupling characteristics. The Si/alpha-Fe2O3 (50 nm)/NiFe(5 nm) bilayer had H-ex=62.5 Oe, H-c=137.5 Oe, while the Si/NiFe(5 nm)/alpha-Fe2O3(50 nm) bilayer had H-ex=4.5 Oe, H-c=9.5 Oe. The larger exchange bias field of alpha-Fe2O3/NiFe bilayer was mainly attributed to good crystallinity of alpha-Fe2O3 and the smooth interface between NiFe and alpha-Fe2O3. The interfacial exchange energy, J(ex) was also calculated for these two bilayers. The case of the rougher surface of bilayer (Si/NiFe/alpha-Fe2O3) exhibited smaller interfacial exchange energy. In order to verify the effect of alpha-Fe2O3 crystal structure on the exchange bias coupling characteristics, Ti (hcp), Zr (hcp), Ta (bcc), and Cu (fcc) were used as buffer layers for the Si/buffer layer/alpha-Fe2O3/NiFe structures. Ti and Zr buffer layers showed good exchange coupling performance, which was strongly related to good crystal matching with alpha-Fe2O3, but there was no exchange coupling improvement in the case of Ta and Cu buffer layers. (C) 2000 American Institute of Physics. [S0021-8979(00)93808-8]. C1 Univ Minnesota, MINT, Minneapolis, MN 55455 USA. NIST, Magnet Mat Grp, Gaithersburg, MD 20899 USA. RP Bae, S (reprint author), Univ Minnesota, MINT, Minneapolis, MN 55455 USA. NR 5 TC 18 Z9 19 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 1 PY 2000 VL 87 IS 9 BP 6650 EP 6652 DI 10.1063/1.372799 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800249 ER PT J AU Bae, S Judy, JH Egelhoff, WF Chen, PJ AF Bae, S Judy, JH Egelhoff, WF Chen, PJ TI Bottom giant magnetoresistance spin valves using a radio frequency reactive bias-sputtered alpha-Fe2O3 antiferromagnetic layer SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc AB The giant magnetoresistance (GMR) characteristics were investigated for rf reactive bias-sputtered alpha-Fe2O3(50 nm) based bottom spin-valve structures. The GMR ratio of this structure was found to be affected by Cu interlayer thickness. When the Cu interlayer thickness was changed from 1.6 to 3.1 nm, the GMR ratio varied from 14.2%(t(cu)=1.8 nm) to 8.3%(t(cu)=3.1 nm). The MR sensitivity and MR ratio dependence were studied for Si/alpha-Fe2O3(50 nm)/(NiFe, or Co)/Cu(2.3 nm)/(NiFe, or Co) structures. The MR ratio of NiFe(5.0%) based spin valve was much smaller than that of Co(16.1%), but it (0.6%/Oe) showed much higher MR sensitivity than that of Co(0.3%/Oe). The alpha-Fe2O3 input sputtering power was also changed from 600 to 1000 W for Si/alpha-Fe2O3(50 nm)/Co(or NiFe)/Cu(2.3 nm)/Co(or NiFe) structures. With increasing input power, the MR ratio increased for both Co (up to 15%) and NiFe (up to 3.1%). The main reason for the increase of MR ratio was attributed to the smoother surface. The average surface roughness measured by ex-situ AFM had 1.38 nm (600 W), 0.9 nm (800 W), and 0.87 nm (1000 W), respectively. (C) 2000 American Institute of Physics. [S0021-8979(00)44208-8]. C1 Univ Minnesota, MINT, Minneapolis, MN 55455 USA. NIST, Magnet Mat Grp, Gaithersburg, MD 20899 USA. RP Bae, S (reprint author), Univ Minnesota, MINT, Minneapolis, MN 55455 USA. NR 7 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 6980 EP 6982 DI 10.1063/1.372906 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800356 ER PT J AU Chopra, HD Yang, DX Chen, PJ Egelhoff, WF AF Chopra, HD Yang, DX Chen, PJ Egelhoff, WF TI Contributions to switching field in NiO-Co-Cu-based spin valves SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID GIANT MAGNETORESISTANCE; MULTILAYERS AB The present study shows that the often observed and undesirable coercivity enhancement in the free Co layer of spin valves result from magnetostatic coupling between domain walls in the free Co layer and high coercivity NiO-pinned Co layer. The observed escape fields, in excess of intrinsic coercivity of Co single film, required to overcome magnetostatic coupling between domain walls are in agreement with theoretically predicted values. (C) 2000 American Institute of Physics. [S0021-8979(00)63108-0]. C1 SUNY Buffalo, Dept Mech & Aerosp Engn, Mat Program, Thin Film & Nanosynth Lab, Buffalo, NY 14260 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP SUNY Buffalo, Dept Mech & Aerosp Engn, Mat Program, Thin Film & Nanosynth Lab, Buffalo, NY 14260 USA. EM hchopra@eng.buffalo.edu NR 13 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 6986 EP 6988 DI 10.1063/1.373426 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800358 ER PT J AU McMichael, RD Eicke, J Donahue, MJ Porter, DG AF McMichael, RD Eicke, J Donahue, MJ Porter, DG TI Domain wall traps for low-field switching of submicron elements SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc AB In magnetic random access memory, power consumption depends on the coercivity of the magnetic elements in the memory cells. In this article a new method is described that uses a "domain wall trap" element shape to reduce both the coercivity and the dependence of coercivity on element size in submicron magnetic elements. Micromagnetic simulations of a shaped permalloy element show coercivity less than one tenth the coercivity calculated for a rectangular permalloy element of the same size. The switching times for the domain wall traps are shown to be comparable to those of rectangular elements. [S0021-8979(00)94808-4]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. RP McMichael, RD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012; OI McMichael, Robert/0000-0002-1372-664X NR 7 TC 46 Z9 46 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 1 PY 2000 VL 87 IS 9 BP 7058 EP 7060 DI 10.1063/1.372930 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800382 ER PT J AU Russek, SE Kaka, S Donahue, MJ AF Russek, SE Kaka, S Donahue, MJ TI High-speed dynamics, damping, and relaxation times in submicrometer spin-valve devices SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID PERMALLOY AB The dynamical response of spin-valve devices with linewidths of 0.8 mu m has been measured after excitation with 160 ps magnetic impulses. The devices show resonant frequencies of 2-4 GHz which determine the upper limit of their operation frequency. The dynamical response can be fit with Landau-Lifshitz models to extract an effective uniform-mode damping constant, alpha(um). The measured values of alpha(um) were between 0.04 and 0.01 depending on the magnitude of the longitudinal bias field. The appropriate damping coefficient for use in micromagnetic modeling, alpha(mm), was extracted from the dynamical response with large longitudinal bias field. This value was used to model the switching of a 0.1 mu mx1.0 mu m magnetoresistive random access memory cell. The micromagnetic model included shape disorder that is expected to be found in real devices. The simulations showed that, while the magnetization reverses rapidly (< 0.5 ns), it took several nanoseconds for the energy to be removed from the magnetic system. The switching energy was stored in short wavelength magnetic fluctuations that could dramatically affect the re-reversal process 1-2 ns after the first reversal. [S0021-8979(00)70908-X]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Math & Computat Sci Div, Gaithersburg, MD 20899 USA. RP Russek, SE (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. NR 8 TC 45 Z9 45 U1 0 U2 8 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 1 PY 2000 VL 87 IS 9 BP 7070 EP 7072 DI 10.1063/1.372934 PN 3 PG 3 WC Physics, Applied SC Physics GA 308TK UT WOS:000086728800386 ER PT J AU Jorgensen, DP Shepherd, TR Goldstein, AS AF Jorgensen, DP Shepherd, TR Goldstein, AS TI A dual-pulse repetition frequency scheme for mitigating velocity ambiguities of the NOAA P-3 airborne Doppler radar SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB To mitigate some of the deleterious effects of the relatively small unambiguous Doppler velocity range (Nyquist interval) of airborne X-band Doppler radars, a technique has been developed to extend this interval. This technique, termed the batch mode dual-PRE (pulse repetition frequency) technique, utilizes two batches of pulses that are each averaged to produce two velocity estimates at each range bin, with each batch at a different sampling rate. Comparison of the two velocity estimates produces a difference velocity that is used to dealias the second estimate within an extended Velocity range that is larger than the Nyquist velocities of either of the two original samples. In this implementation, the choices of the two PRFs are restricted to ratios of 3/2 or 4/3 of the lowest PRF. Due to the spread of the input Doppler spectrum and spatial displacement from one radial to the next, however, this batch-mode technique can produce processor velocity dealiasing mistakes, particularly in high wind shear environments. For PRFs less than about 2000 s(-1), processor mistakes can easily exceed 10% of all data points. With higher PRFs using the 3/2 ratio, the number of processor mistakes decreases to a few percent of the total number of samples even when observing strong convective storms and mesoscale convective systems. Test results from convective storm environments are shown from the airborne Doppler radar operated on the National Oceanic and Atmospheric Administration's P-3 instrumented aircraft for a variety of base PRFs and ratios to show the utility of this technique. C1 NOAA, Natl Severe Storms Lab, Mesoscale Res & Applicat Div Boulder, Boulder, CO 80303 USA. NOAA, Aercraft Operat Ctr, MacDill AF Base, FL USA. RP Jorgensen, DP (reprint author), NOAA, Natl Severe Storms Lab, Mesoscale Res & Applicat Div Boulder, Mail Code N-C-MRD,325 Broadway, Boulder, CO 80303 USA. NR 13 TC 26 Z9 29 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAY PY 2000 VL 17 IS 5 BP 585 EP 594 DI 10.1175/1520-0426(2000)017<0585:ADPRFS>2.0.CO;2 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 319ET UT WOS:000087329100001 ER PT J AU Worthington, RM Palmer, RD Fukao, S Yamamoto, M Astin, I AF Worthington, RM Palmer, RD Fukao, S Yamamoto, M Astin, I TI Rapid variations in echo power maps of VHF radar backscatter from the lower atmosphere SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID INDIAN MST RADAR; SPECULAR REFLECTION ECHOES; RADIO-WAVE SCATTERERS; BEAM INCIDENCE ANGLES; ASPECT SENSITIVITY; MU-RADAR; ANDENES 69-DEGREES-N,16-DEGREES-E; LOWER STRATOSPHERE; BOUNDARY-LAYER; ST-MODE AB For the first time, echo power maps of aspect-sensitive VHF backscatter are shown, with good time and spatial resolutions, for angles 0 degrees-7 degrees from zenith. Sequences of power maps show large changes in appearance over timescales of a few minutes and height intervals of a few hundred metres. Often, individual power maps are consistent with tilted and distorted specular-type scattering layers, rather than anisotropic turbulence, and the direction of maximum echo power is sometimes several degrees off-vertical. Nevertheless, after time-averaging the variable echo-power patterns, the average pattern can become almost circular and centred on zenith, as has been assumed in the past. Echo power maps measured in strong windshear beneath the jet stream show a skewing of the echo power distribution. However, some power maps in the lower stratosphere: despite stronger wind shear, appear more constrained and their maximum echo power remains closer to zenith. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Wales, Dept Phys, Aberystwyth, Dyfed, Wales. Univ Nebraska, Ctr Electroopt, Dept Elect Engn, Lincoln, NE 68588 USA. Kyoto Univ, Ctr Radio Atmospher Sci, Kyoto, Japan. Univ Reading, Environm Syst Sci Ctr, Reading RG6 2AH, Berks, England. RP Worthington, RM (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. OI Worthington, Richard/0000-0003-0681-5596 NR 40 TC 10 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAY PY 2000 VL 62 IS 7 BP 573 EP 581 DI 10.1016/S1364-6826(00)00010-9 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 333AU UT WOS:000088107200004 ER PT J AU Freitag, MA Gordon, MS Jensen, JH Stevens, WJ AF Freitag, MA Gordon, MS Jensen, JH Stevens, WJ TI Evaluation of charge penetration between distributed multipolar expansions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTERMOLECULAR PAULI REPULSION; FRAGMENT POTENTIAL METHOD; CLOSED-SHELL MOLECULES; APPROXIMATE FORMULA; MODEL; FORCES AB A formula to calculate the charge penetration energy that results when two charge densities overlap has been derived for molecules described by an effective fragment potential (EFP). The method has been compared with the ab initio charge penetration, taken to be the difference between the electrostatic energy from a Morokuma analysis and Stone's Distributed Multipole Analysis. The average absolute difference between the EFP method and the ab initio charge penetration for dimers of methanol, acetonitrile, acetone, DMSO, and dichloromethane at their respective equilibrium geometries is 0.32 kcal mol(-1). (C) 2000 American Institute of Physics. [S0021-9606(00)30817-0]. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Univ Iowa, Dept Chem, Iowa City, IA 52242 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div 838, Gaithersburg, MD 20899 USA. RP Freitag, MA (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RI Jensen, Jan/G-4338-2010 OI Jensen, Jan/0000-0002-1465-1010 NR 22 TC 115 Z9 115 U1 0 U2 18 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 1 PY 2000 VL 112 IS 17 BP 7300 EP 7306 DI 10.1063/1.481370 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 305DH UT WOS:000086523800004 ER PT J AU Votava, O Plusquellic, DF Myers, TL Nesbitt, DJ AF Votava, O Plusquellic, DF Myers, TL Nesbitt, DJ TI Bond-breaking in quantum state selected clusters: Inelastic and nonadiabatic intracluster collision dynamics in Ar-H2O -> Ar+H(S-2)+OH((2)Pi(+/-)(1/2,3/2);N) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 1ST ABSORPTION-BAND; POTENTIAL-ENERGY SURFACE; INFRARED-LASER SPECTROSCOPY; ULTRAFAST REACTION DYNAMICS; PHOTODISSOCIATION DYNAMICS; CROSS-SECTIONS; RECOMBINATION DYNAMICS; VANDERWAALS BONDS; ELECTRON-TRANSFER; WATER AB High-resolution vibrationally mediated IR+UV photodissociation methods are used to investigate the dynamics of H-OH bond breaking in quantum state selected H2O and Ar-H2O van der Waal complexes prepared in a slit supersonic jet expansion. This capability is based on the following strategy: (i) Specific rovibrational quantum states of the Ar-H2O dimer and H2O monomer are optically selected in the second overtone (nu(OH)=3 <-- 0) region with an injection seeded, Fourier transform limited (Delta nu approximate to 160 MHz) optical parametric oscillator. (ii) Selective H-OH bond cleavage of the vibrationally excited H2O subunit in the cluster is achieved by 248 nm or 222 nm UV photolysis. (iii) Multibody collision dynamics between the H, OH, and Ar photofragments are probed via laser induced fluorescence (LIF) on the asymptotic OH rotational, lambda-doublet and spin-orbit distributions. Comparison between cluster (Ar-H2O) and monomer (H2O) data explicitly samples the influence of the Ar "solvent" on the UV photolysis dynamics and in particular highlights the dominant role of intracluster collisions as the fragments recoil. Most importantly, the OH fine structure distributions are found to be dramatically different for Ar-H2O vs H2O photolysis, indicating the major contribution of nonadiabatic events in the photofragmentation dynamics. (C) 2000 American Institute of Physics. [S0021-9606(00)01317-9]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Votava, O (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 52 TC 19 Z9 19 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 1 PY 2000 VL 112 IS 17 BP 7449 EP 7460 DI 10.1063/1.481344 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 305DH UT WOS:000086523800021 ER PT J AU Delworth, TL Greatbatch, RJ AF Delworth, TL Greatbatch, RJ TI Multidecadal thermohaline circulation variability driven by atmospheric surface flux forcing SO JOURNAL OF CLIMATE LA English DT Article ID INTERDECADAL VARIABILITY; COUPLED MODEL; CLIMATE VARIABILITY; TRANSIENT RESPONSES; GRADUAL CHANGES; OCEAN; SEA; OSCILLATION; TEMPERATURE; CO2 AB Previous analyses of an extended integration of the Geophysical Fluid Dynamics Laboratory coupled climate model have revealed pronounced multidecadal Variations of the thermohaline circulation (THC) in the North Atlantic. The purpose of the current work is to assess whether those fluctuations can be viewed as a coupled air-sea mode tin the sense of ENSO), or as an oceanic response to forcing from the atmosphere model, in which large-scale feedbacks from the ocean to the atmospheric circulation are not critical. A series of integrations using the ocean component of the coupled model are performed to address the above question. The ocean model is forced by suitably chosen time series of surface fluxes from either the coupled model or a companion integration of an atmosphere-only model run with a prescribed seasonal cycle of SSTs and sea-ice thickness. These experiments reveal that 1) the previously identified multidecadal THC variations can be largely viewed as an oceanic response to surface flux forcing from the atmosphere model, although air-sea coupling through the thermodynamics appears to modify the amplitude of the variability, and 2) variations in heat flux are the dominant term (relative to the freshwater and momentum fluxes) in driving the THC variability. Experiments driving the ocean model using either high- or low-pass-filtered heat fluxes, with a cutoff period of 20 yr, show that the multidecadal THC variability is driven by the low-frequency portion of the spectrum of atmospheric flux forcing. Analyses have also revealed that the multidecadal THC fluctuations are driven by a spatial pattern of surface heat flux variations that bears a strong resemblance to the North Atlantic oscillation. No conclusive evidence is found that the THC variability is part of a dynamically coupled mode of the atmosphere and ocean models. C1 Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Dalhousie Univ, Dept Oceanog, Halifax, NS B3H 3J5, Canada. RP Delworth, TL (reprint author), Geophys Fluid Dynam Lab, Route 1,Forrestal Campus, Princeton, NJ 08542 USA. RI Delworth, Thomas/C-5191-2014 NR 34 TC 185 Z9 193 U1 2 U2 17 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY 1 PY 2000 VL 13 IS 9 BP 1481 EP 1495 DI 10.1175/1520-0442(2000)013<1481:MTCVDB>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 311UY UT WOS:000086905200004 ER PT J AU Goddard, L Philander, SG AF Goddard, L Philander, SG TI The energetics of El Nino and La Nina SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; AVAILABLE POTENTIAL-ENERGY; ATMOSPHERE OCEAN MODEL; SOUTHERN OSCILLATION; EQUATORIAL CURRENTS; PACIFIC-OCEAN; ENSO; VARIABILITY; CIRCULATION; SIMULATION AB Data from a realistic model of the ocean, forced with observed atmospheric conditions for the period 1953-92, are analyzed to determine the energetics of interannual variability in the tropical Pacific. The work done by the winds on the ocean, rather than generating kinetic energy, does work against pressure gradients and generates buoyancy power, which in turn is responsible for the rate of change of available potential energy (APE). This means interannual fluctuations in work done by the wind have a phase that leads variations in APE. Variations in the sea surface temperature (SST) of the eastern equatorial Pacific and in APE are highly correlated and in phase so that changes in the work done by the wind are precursors of El Nino. The wind does positive work on the ocean during the half cycle that starts with the peak of El Nino and continues into La Nina; it does negative work during the remaining half cycle. The results corroborate the delayed oscillator mechanism that qualitatively describes the deterministic behavior of ENSO. In that paradigm, a thermocline perturbation appearing in the western equatorial Pacific affects the transition from one phase of ENSO to the next when that perturbation arrives in the eastern equatorial Pacific where it influences SST. The analysis of energetics indicates that the transition starts earlier, during La Nina, when the perturbation is still in the far western equatorial Pacific. Although the perturbation at that stage affects the thermal structure mainly in the thermocline, at depth, the associated currents are manifest at the surface and immediately affect work done by the wind. For the simulation presented here, the change in energy resulting from adjustment processes far outweighs that due to stochastic processes, such as intraseasonal wind bursts, at least during periods of successive El Nino and La Nina events. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Goddard, L (reprint author), Columbia Univ, Lamont Doherty Geol Observ, Int Res Inst Climate Predict, 61 Route 9W, Palisades, NY 10964 USA. NR 45 TC 29 Z9 32 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAY 1 PY 2000 VL 13 IS 9 BP 1496 EP 1516 DI 10.1175/1520-0442(2000)013<1496:TEOENO>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 311UY UT WOS:000086905200005 ER PT J AU Asthagiri, D Lenhoff, AM Gallagher, DT AF Asthagiri, D Lenhoff, AM Gallagher, DT TI Role of competitive interactions in growth rate trends of subtilisin s88 crystals SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE crystal growth models; self-poisoning; crystal contacts; interaction energy ID TETRAGONAL LYSOZYME CRYSTALS; PROTEIN; MECHANISM; FACE AB An orthorhombic crystal form of subtilisin BPN' variant s88 exhibits a systematic variation in growth rates of its three unique faces, resulting in pronounced variations in crystal morphology as a function of the ionic strength (Gallagher et al., J. Crystal Growth 193 (1998) 665). We have sought to explain these observations by performing energetics calculations using the full structural details of the protein. The approach of correlating growth rates with the strength of interactions of molecular pairs in the crystal proved unsatisfactory. The attachment of protein molecules to growing crystal faces is a stochastic process: a protein molecule samples numerous configurational (orientational and translational) states before attaching to the crystal in a configuration consistent with the crystal symmetry. This search-and-bind process determines the rate of crystal growth. We present a simplified approach that mimics this dynamical process: we perform docking of a protein molecule with another protein molecule or a cluster of molecules. An analysis of the bound configurations reveals the presence of orientations that are incommensurate with the crystal symmetry but in which a protein molecule can also bind strongly to the crystal face. Such improperly oriented molecules can be thought of as competitive inhibitors, and their presence is shown to affect the growth rate. Thus procedures aimed at decreasing the effect of such competitive inhibition, or conversely increasing the specificity of protein-protein interactions forming the crystal, are expected to offer better control of crystal growth rates. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Delaware, Dept Chem Engn, Ctr Mol & Engn Thermodynam, Newark, DE 19716 USA. NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Lenhoff, AM (reprint author), Univ Delaware, Dept Chem Engn, Ctr Mol & Engn Thermodynam, Newark, DE 19716 USA. RI Asthagiri, Dilipkumar/A-3383-2010; Asthagiri, Dilipkumar/P-9450-2016; OI Asthagiri, Dilipkumar/0000-0001-5869-0807; Lenhoff, Abraham/0000-0002-7831-219X NR 24 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAY PY 2000 VL 212 IS 3-4 BP 543 EP 554 DI 10.1016/S0022-0248(00)00200-1 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 310GY UT WOS:000086819200025 ER PT J AU Pan, WQ Gallagher, DT AF Pan, WQ Gallagher, DT TI Probing protein interaction chemistry through crystal growth: structure, mutation, and mechanism in subtilisin s88 SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE crystal structure; lattice packing; mutation; protein crystal growth; subtilisin ID MACROMOLECULAR STRUCTURES; MORPHOLOGY AB Observations of systematic variation in the shapes of protein crystals have unique potential to report chemical effects on protein-protein interactions, because diffraction can be used to image the detailed structure that links an easily controlled "cause" (change in chemical conditions) with an easily observed "effect" (change in crystal shape). Crystal shape correlates directly with the relative growth rates of the various faces. By studying cases of known structures in which crystal shape varies systematically with some solution parameter (pH, ionic strength, concentration of a specific solute, etc.), it is sometimes possible to correlate that parameter with its effect on a particular crystal contact. Such correlations provide the basis for models of how solution parameters affect protein-protein interactions. We have applied this technique in a model system involving a subtilisin BPN' variant. Crystal shape varies systematically with pH and ionic strength, an effect that has been traced to a specific interaction in one crystal contact. Mutation of an Asp sidechain in this contact (to Asn) eliminates the morphology variation effect, confirming the key role of this residue in the observed shape effect, and enabling the mechanism to be placed in a mathematical framework. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Gallagher, DT (reprint author), NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 18 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD MAY PY 2000 VL 212 IS 3-4 BP 555 EP 563 DI 10.1016/S0022-0248(00)00250-5 PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 310GY UT WOS:000086819200026 ER PT J AU Jablonski, A Powell, CJ AF Jablonski, A Powell, CJ TI Relationships between electron inelastic mean free paths, effective attenuation lengths, and mean escape depths (vol 100, pg 137, 1999) SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Correction C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw, Poland. RP Powell, CJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 1 TC 7 Z9 7 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD MAY PY 2000 VL 107 IS 2 BP 201 EP 201 DI 10.1016/S0368-2048(00)00150-X PG 1 WC Spectroscopy SC Spectroscopy GA 312NX UT WOS:000086950300012 ER PT J AU O'Reilly, PT Canino, MF Bailey, KM Bentzen, P AF O'Reilly, PT Canino, MF Bailey, KM Bentzen, P TI Isolation of twenty low stutter di- and tetranucleotide microsatellites for population analyses of walleye pollock and other gadoids SO JOURNAL OF FISH BIOLOGY LA English DT Article DE walleye pollock; microsatellite; PCR stutter; short allele dominance ID ATLANTIC SALMON; TANDEM REPEATS; SHADOW BANDS; DINUCLEOTIDE; PCR; MARKERS; DNA; AMPLIFICATION; GENOME; LOCI AB Fourteen tetra- and six dinucleotide microsatellites. which exhibit minimal stuttering following amplification via PCR were developed from walleye pollock Theragra chalcogramma. Most of these loci were isolated from a library enriched for tetranucleotide microsatellites by hybridization of genomic DNA to (gata)(7) oligonucleotides bound to streptavidin-coated paramagnetic beads. The average heterozygosity of these loci is similar to 80%, and ranges from 53-95%. Mendelian inheritance was confirmed in five families, each consisting of a minimum of 10 or more offspring. Primer sets for all 20 loci were also evaluated in Arctic cod Boreogadus saida, Pacific cod Gadus macrocephalus. Pacific tomcod Microgadus proximus, saffron cod Eleginus gracilis, Pacific hake Merluccius productus. Atlantic cod Gadus morhua. haddock Melanogrammus aelefinus, blue whiting, Merluccius productus poutassou, and European hake Merluccius merluccius. In each of these species, 3-19 primer sets amplified variable microsatellite loci. These loci, which exhibit little stutter and moderate to high variability, should be useful population markers in pollock and other gadoid fishes. (C) 2000 The Fisheries Society or the British Isles. C1 Univ Washington, Marine Mol Biotechnol Lab, Sch Fisheries, Seattle, WA 98105 USA. NOAA, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP O'Reilly, PT (reprint author), Univ Washington, Marine Mol Biotechnol Lab, Sch Fisheries, 3707 Brooklyn Ave NE, Seattle, WA 98105 USA. NR 38 TC 78 Z9 82 U1 1 U2 13 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD MAY PY 2000 VL 56 IS 5 BP 1074 EP 1086 DI 10.1111/j.1095-8649.2000.tb02124.x PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 318JX UT WOS:000087281500004 ER PT J AU Arge, CN Pizzo, VJ AF Arge, CN Pizzo, VJ TI Improvement in the prediction of solar wind conditions using near-real time solar magnetic field updates SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HELIOSPHERIC CURRENT SHEET; CORONAL HOLES; MODEL; FLUX AB The Wang-Sheeley model is an empirical model that can predict the background solar wind speed and interplanetary magnetic field (IMF) polarity. We make a number of modifications to the basic technique that greatly improve the performance and reliability of the model. First, we establish a continuous empirical function that relates magnetic expansion factor to solar wind velocity at the source surface. Second, we propagate the wind from the source surface to the Earth using the assumption of radial streams and a simple scheme to account for their interactions. Third, we develop and apply a method for identifying and removing problematic magnetograms from the Wilcox Solar Observatory (WSO). Fourth, we correct WSO line-of-sight magnetograms for polar field strength modulation effects that result from the annual variation in the solar b angle. Fifth, we explore a number of techniques to optimize construction of daily updated synoptic maps from the WSO magnetograms. We report on a comprehensive statistical analysis comparing Wang-Sheeley model predictions with the WIND satellite data set during a 3-year period centered about the May 1996 solar minimum. The predicted and observed solar wind speeds have a statistically significant correlation (similar to 0.4) and an average fractional deviation of 0.15. When a single (6-month) period with large data gaps is excluded from the comparison, the solar wind speed is correctly predicted to within 10-15%. The IMF polarity is correctly predicted similar to 75% of the time. The solar wind prediction technique presented here has direct applications to space weather research and forecasting. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Arge, CN (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NR 23 TC 354 Z9 359 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 2000 VL 105 IS A5 BP 10465 EP 10479 DI 10.1029/1999JA000262 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 309AQ UT WOS:000086745400023 ER PT J AU Hill, SM Solomon, SC Cleary, DD Broadfoot, AL AF Hill, SM Solomon, SC Cleary, DD Broadfoot, AL TI Temperature dependence of the reaction N-2(A (3)Sigma(+)(u))+O in the terrestrial thermosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID ELECTRON-IMPACT EXCITATION; DISSOCIATIVE RECOMBINATION COEFFICIENTS; MIDDLE ULTRAVIOLET DAYGLOW; POTENTIAL-ENERGY SURFACES; SOLAR EUV FLUX; ATOMIC OXYGEN; CROSS-SECTIONS; RATE CONSTANTS; VIBRATIONAL POPULATIONS; SATELLITE MEASUREMENTS AB Previous models for dayglow and auroral emissions of the N-2(A (3)Sigma(u)(+) --> X (1)Sigma(g)(+)) Vegard-Kaplan (VK) bands and O(S-1) lines, when based on laboratory rate coefficients, disagree with observations. The problem has two parts: the overall rate of N-2(A)+O and the state-specific yield of O(1S). Resolving these discrepancies should yield more accurate determinations of atomic oxygen density by remote sensing of the 2972 and 5577 Angstrom lines. To solve the problem, the sources and sinks of O(S-1) are considered using dayglow observations from 105 to 315 km and a numerical model. Line and band intensities are extracted from the data using a multiple regression fit to synthetic spectra. A photoelectron and photochemical model is used to analyze the resulting vertical emission profiles. N2 Second Positive (2P) altitude profiles indicate that photoelectron excitation of the Nz triplet system is modeled with an absolute uncertainty of +/-23%. The VK/2P intensity ratio suggests that laboratory rate coefficients for the reaction N-2(A; nu'=0,1,2) + O should be increased by a factor of 1.74 to 2.34. However, the laboratory rates were measured at room temperature. When the effect of high thermospheric temperatures on collision frequency is accounted for, the rate coefficients for nu'=0,1, and 2 are found to be (3.4+/-0.8)x10(-11) (T/298)(1/2), (5.6+/-1.3)x10(-11) (T/298)(1/2), and (4.8+/-1.2)x10(-11) 1(T/298)(1/2) cm(3)s(-1) At 298 K, the nu'=0 and 2 values are within 5% of the laboratory values, but for nu'=1 the value is 40% larger than the laboratory value. The effective quantum yield of O(1S) by N-2(A)+O is found to be 0.47+/-0.17. The observations support a photoelectron cross section for O(S-1) that is consistent with laboratory measurements, but about 2.0 times larger than theoretical calculations. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Naval Postgrad Sch, Dept Phys, Monterey, CA USA. RP Hill, SM (reprint author), NOAA, Space Environm Ctr, 325 Broadway, Boulder, CO 80303 USA. RI Solomon, Stanley/J-4847-2012 OI Solomon, Stanley/0000-0002-5291-3034 NR 84 TC 16 Z9 16 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 2000 VL 105 IS A5 BP 10615 EP 10629 DI 10.1029/1999JA000395 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 309AQ UT WOS:000086745400035 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 2000 VL 105 IS A5 BP 10789 EP 10789 DI 10.1029/2000JA900045 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 309AQ UT WOS:000086745400053 ER PT J AU Tang, HC Nguyen, T Chuang, TJ Chin, J Lesko, J Wu, HF AF Tang, HC Nguyen, T Chuang, TJ Chin, J Lesko, J Wu, HF TI Fatigue model for fiber-reinforced polymeric composites SO JOURNAL OF MATERIALS IN CIVIL ENGINEERING LA English DT Article ID DEGRADATION; LIFE AB A fatigue model based on cumulative damage is developed for predicting the fatigue Life of fiber-reinforced polymeric composites. This model incorporates applied maximum stress, stress amplitude, loading frequency, residual tensile modulus, and material constants as parameters. The model is verified with experimental fatigue data on a glass fiber/vinyl ester composite. While the specimens are exposed to air, freshwater, or seawater at 30 degrees C, they are subjected to tension-tension stress at four levels of applied maximum tensile stress in each of two frequencies. Both the residual mechanical properties at specified loading cycles and the number of cycles at which the specimens fail are measured. The results show that, for the material used in this study, the loss in residual tensile strength and modulus in saltwater is approximately the same as that in freshwater and that the fatigue life in these aqueous environments is shorter than that in air. Numerical analysis is carried out to determine the material constants of the composite. The fatigue model agrees well with the experimental data. The model can be used to predict the fatigue life of the polymeric composites subjected to an applied load in different environments and to predict the residual tensile modulus after a number of cycles of service at a given load. C1 Natl Inst Stand & Technol, Informat Technol Lab, High Perf Sys & Serv Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Build Mat Div, Build & Fire Res Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Virginia Polytech Inst & State Univ, Engn Sci & Mech Dept, Blacksburg, VA 24061 USA. Natl Inst Stand & Technol, Program Mgr Compos Mat, Adv Technol Program, Gaithersburg, MD 20899 USA. RP Tang, HC (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, High Perf Sys & Serv Div, Gaithersburg, MD 20899 USA. NR 32 TC 12 Z9 12 U1 0 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0899-1561 J9 J MATER CIVIL ENG JI J. Mater. Civ. Eng. PD MAY PY 2000 VL 12 IS 2 BP 97 EP 104 DI 10.1061/(ASCE)0899-1561(2000)12:2(97) PG 8 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 306NW UT WOS:000086603600001 ER PT J AU Matsuya, S Takagi, S Chow, LC AF Matsuya, S Takagi, S Chow, LC TI Effect of mixing ratio and pH on the reaction between Ca-4(PO4)(2)O and CaHPO4 SO JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE LA English DT Article ID CALCIUM-PHOSPHATE CEMENTS; HYDROXYAPATITE FORMATION; SETTING REACTIONS; LOW-TEMPERATURE; DEFICIENT; KINETICS; BEHAVIOR AB The reaction of Ca(PO4)(2)O (TTCP) and CaHPO4 (DCPA) in an aqueous solution has been shown to be responsible for the hardening of a calcium phosphate cement. This reaction was investigated by monitoring pH changes and composition of solid phases. In the first set of experiments (no attempt to control pH), 2.5 g each of mixtures of TTCP/DCPA, molar ratio from 0.25 to 2, was placed in 12.5 mL of 0.15 mol/L KCl solution, at initial pH about 7, and the pH was allowed to drift for 24 h. Results show that at any time up to 24 h, the pHs were higher for slurries with higher TTCP/DCPA molar ratios. For the slurries with TTCP/DCPA molar ratio of greater than or equal to 0.83, the 24 h pHs of the slurries were 9 to 11, whereas for those with TTCP/DCPA of less than or equal to 0.67, the pHs were between 5.3 and 7. The slurries with TTCP/DCPA molar ratios between 0.5 and 1 (Ca/P molar ratio=1.5 to 1.67) reacted completely within 24 h to form hydroxyapatite (OHAp), Ca-5(PO4)(3)OH. In the second set of experiments, 2 g of an equimolar TTCP and DCPA mixture was placed in 20 mL of 0.15 mol/L KCl solution. The pH values were kept constant (6, 8 or 10) by using H3PO4 and Ca(OH)(2) or HCl and KOH as titrant solutions. At pH 8, DCPA and TTCP dissolved at about the same rate, whereas at pH 10, DCPA was consumed more rapidly than TTCP. At both pHs, OHAp was the only product formed. However, at pH 6, the composition of reaction products depended on the types of the titrants used. Specifically when H3PO4 and Ca(OH)(2) were used, hydrolysis of TTCP was the predominant reaction and both octacalcium phosphate and OHAp were formed. But, when HCl and KOH were used, only OHAp was formed. In this case hydrolysis of TTCP and DCPA appeared to proceed independently with TTCP hydrolysis beginning immediately and progressing slowly through 48 h while the DCPA hydrolysis began several hours after the reaction started but was completed in 24 h. (C) 2000 Kluwer Academic Publishers. C1 Kyushu Univ, Fac Dent, Dept Dent Mat Engn, Fukuoka 8128582, Japan. Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Matsuya, S (reprint author), Kyushu Univ, Fac Dent, Dept Dent Mat Engn, Fukuoka 8128582, Japan. NR 25 TC 23 Z9 24 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0957-4530 J9 J MATER SCI-MATER M JI J. Mater. Sci.-Mater. Med. PD MAY PY 2000 VL 11 IS 5 BP 305 EP 311 DI 10.1023/A:1008961314500 PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 295GM UT WOS:000085958400007 PM 15348028 ER PT J AU Allen, MD Evenson, KM Gillett, DA Brown, JM AF Allen, MD Evenson, KM Gillett, DA Brown, JM TI Far-infrared laser magnetic resonance spectroscopic study of the nu(2) bending fundamental of the CCN radical in its (X)over-tilde(2)Pi(r) state SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE FIR LMR; bending vibrational transitions; Renner-Teller effect ID INDUCED FLUORESCENCE-SPECTRUM; EXCITATION SPECTROSCOPY; MICROWAVE SPECTROSCOPY; BAND; PARAMETERS; VIBRATION; 2-DELTA AB Bending vibration-rotation transitions between the (010) mu(2)Sigma(-) and (000) (II)-I-2, vibronic states of the CCN radical in its ground electronic stare have been observed using far-infrared laser magnetic resonance (FIR LMR) spectroscopy. Thirteen FIR laser lines were used to record 769 resonances. The LMR data, combined with previous data, were used to determine vibrational, Renner-Teller, fine-structure, rotational, hyperfine, and molecular g-factor parameters using a least-squares fitting routine. The model used was an NZ effective Hamiltonian modified to include the Renner-Teller effect explicitly in a (II)-I-2 electronic state. The band origin for the (010) mu(2)Sigma(-) - <-- (000) (X) over tilde(2)II, transition was determined to be 179.598176 +/- 0.000067 cm(-1). The spin-orbit splitting in the ground state was refined and the complete set of N-14-hyperfine parameters determined for the first time. C1 Natl Inst Stand & Technol, Div Time & Frequency 847, Boulder, CO 80303 USA. Lambda Phys GmbH, D-37079 Gottingen, Germany. Phys & Theoret Chem Lab, Oxford OX1 3QZ, England. RP Allen, MD (reprint author), Natl Inst Stand & Technol, Div Time & Frequency 847, 325 Broadway, Boulder, CO 80303 USA. NR 39 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 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 2000 VL 201 IS 1 BP 18 EP 29 DI 10.1006/jmsp.2000.8075 PG 12 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 304EX UT WOS:000086471100003 ER PT J AU Mate, B Fraser, GT Lafferty, WJ AF Mate, B Fraser, GT Lafferty, WJ TI Intensity of the simultaneous vibrational absorption CO2 (v(3)=1)+N-2 (v=1)<- CO2 (v(3)=0)+N-2 (v=0) at 4680 cm(-1) SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID BAND; SPECTRA C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Mate, B (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RI Mate, Belen/F-1135-2016 OI Mate, Belen/0000-0002-5478-8644 NR 15 TC 8 Z9 8 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD MAY PY 2000 VL 201 IS 1 BP 175 EP 177 DI 10.1006/jmsp.2000.8074 PG 3 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 304EX UT WOS:000086471100021 ER PT J AU Christophorou, LG Olthoff, JK AF Christophorou, LG Olthoff, JK TI Electron interactions with SF6 SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE SF6; sulfur hexafluoride; electron interactions; scattering; ionization; attachment; dissociation; cross section; coefficients; transport; negative ions ID BOLTZMANN-EQUATION ANALYSIS; IONIZATION CROSS-SECTIONS; GENERALIZED OSCILLATOR-STRENGTHS; MONTE-CARLO SIMULATION; IMPACT CORE EXCITATION; HIGH RYDBERG STATES; ION-PAIR FORMATION; SULFUR-HEXAFLUORIDE; NEGATIVE-IONS; TRANSPORT-COEFFICIENTS AB Sulfur hexafluoride (SF6) is commonly used as a gaseous dielectric and as a plasma etching gas. In this work, the state of knowledge on electron-interaction cross sections and electron-swarm parameters in SF6 is comprehensively reviewed and critically assessed. Cross sections are presented and discussed for the following scattering processes: total electron scattering; differential elastic; elastic integral; elastic momentum; total vibrational; total and partial ionization; total dissociative and nondissociative electron attachment; and dissociation into neutrals. Coefficients for electron-impact ionization, effective ionization, electron attachment, electron drift, and electron diffusion are also reviewed and assessed. In addition, complementary information on the electronic and molecular structure of the SF6 molecule and on electron detachment and ion transport in parent SF6 gas is provided that allows a better understanding of the nature of the cross sections and swarm parameters. The assessed data are used to deduce cross sections and coefficients for which there exist no direct measurements at the present time. The present work on electron interactions with the SF6 molecule reveals a rather simple picture which can be summarized as follows: (1) Elastic electron scattering is the most significant electron scattering process over the electron energy range from similar to 0.01 to similar to 1000 eV. (2) Below 15 eV the most distinct inelastic energy-loss process is vibrational excitation-direct dipole excitation involving the nu(3) mode and indirect vibrational excitation via negative ion states involving the vl mode. (3) Below similar to 0.1 eV electron attachment forming SF6- is the most dominant interaction (along with elastic scattering). Above this energy, the cross sections for dissociative electron attachment forming fragment anions [principally SFx- (x=3, 4, and 5) and F-] are appreciable, with the room temperature total electron attachment cross section dominated by the formation of SF5- between similar to 0.3 and 1.5 eV and by the formation of F- beyond similar to 2.0 eV. (4) Above similar to 16 eV dissociative ionization becomes significant, generating principally SFx+ (x=1, 3, 4, and 5) and F+ positive-ion fragments which, together with elastic electron scattering, makes up most of the total electron scattering cross section. (5) Electron-impact dissociation into neutral fragments SFx (x=1, 2, and 3) and F occurs above similar to 15 eV, with cross section values potentially exceeding those for ionization for electron energies near 20 eV. (6) The total electron scattering cross section exhibits distinct structure due to negative-ion resonances near 0.0, 2.5, 7.0, and 11.9 eV. The most significant data needs are for direct measurements of vibrational excitation cross sections, for cross sections for electron-impact dissociation into neutral fragments, and for the momentum transfer cross section at low energies. (C) 2000 American Institute of Physics. [S0047-2689(00)00204-X]. C1 Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Christophorou, LG (reprint author), Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 343 TC 262 Z9 267 U1 5 U2 72 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD MAY-JUN PY 2000 VL 29 IS 3 BP 267 EP 330 DI 10.1063/1.1288407 PG 64 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 360NZ UT WOS:000089675300001 ER PT J AU Lemmon, EW Jacobsen, RT Penoncello, SG Friend, DG AF Lemmon, EW Jacobsen, RT Penoncello, SG Friend, DG TI Thermodynamic properties of air and mixtures of nitrogen, argon, and oxygen from 60 to 2000 K at pressures to 2000 MPa SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE air; argon; density; equation of state; mixtures; nitrogen; oxygen; pressure; thermodynamic properties; vapor-liquid equilibrium ID VAPOR-LIQUID-EQUILIBRIUM; TEMPERATURE-RANGE; STATE; EQUATION; FORMULATION; DENSITY; METHANE; MODEL; SOUND; GAS AB A thermodynamic property formulation for standard dry air based upon available experimental p-rho-T, heat capacity, speed of sound, and vapor-liquid equilibrium data is presented. This formulation is valid for liquid, vapor, and supercritical air at temperatures from the solidification point on the bubble-point curve (59.75 K) to 2000 K at pressures up to 2000 MPa. In the absence of reliable experimental data for air above 873 K and 70 MPa, air properties were predicted from nitrogen data in this region. These values were included in the determination of the formulation to extend the range of validity. Experimental shock tube measurements on air give an indication of the extrapolation behavior of the equation of state up to temperatures and pressures of 5000 K and 28 GPa. The available measurements of thermodynamic properties of air are summarized and analyzed. Separate ancillary equations for the calculation of dew and bubble-point pressures and densities of air are presented. In the range from the solidification point to 873 Kat pressures to 70 MPa, the estimated uncertainty of density values calculated with the equation of state is 0.1%. The estimated uncertainty of calculated speed of sound values is 0.2% and that for calculated heat capacities is 1%. At temperatures above 873 K and 70 MPa, the estimated uncertainty of calculated density values is 0.5% increasing to 1.0% at 2000 K and 2000 MPa. In addition to the equation of state for standard air, a mixture model explicit in Helmholtz energy has been developed which is capable of calculating the thermodynamic properties of mixtures containing nitrogen, argon, and oxygen. This model is Valid for temperatures from the solidification point on the bubble-point curve to 1000 K at pressures up to 100 MPa over all compositions. The, Helmholtz energy of the mixture is the sum of the ideal gas contribution, the real gas contribution, and the contribution from mixing. The contribution from mixing is given by a single generalized equation which is applied to all mixtures used in this work. The independent variables are the reduced density and reduced temperature. The model may be used to calculate the thermodynamic properties of mixtures at various compositions including dew and bubble-point properties and critical points. It incorporates the most accurate published equation of state for each pure fluid. The mixture model may be used to calculate the properties of mixtures generally within the experimental accuracies of the available measured properties. The estimated uncertainty of calculated properties is 0.1% in density, 0.2% in the speed of sound, and 1% in heat capacities. Calculated dew and bubble-point pressures are generally accurate to within 1%. (C) 2000 American Institute of Physics. [S0047-2689(00)00103-3]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Idaho, Coll Engn, Ctr Appl Thermodynam Studies, Moscow, ID 83844 USA. RP Lemmon, EW (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 127 TC 182 Z9 190 U1 8 U2 60 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD MAY-JUN PY 2000 VL 29 IS 3 BP 331 EP 385 DI 10.1063/1.1285884 PG 55 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 360NZ UT WOS:000089675300002 ER PT J AU Vallis, GK AF Vallis, GK TI Large-scale circulation and production of stratification: Effects of wind, geometry, and diffusion SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID WORLD OCEAN; THERMOHALINE CIRCULATION; VENTILATED THERMOCLINE; PARAMETER SENSITIVITY; ABYSSAL OCEAN; WATER MASSES; MODEL; DRIVEN; VARIABILITY AB The combined effects of wind, geometry, and diffusion on the stratification and circulation of the ocean are explored by numerical and analytical methods. In particular, the production of deep stratification in a simply configured numerical model with small diffusivity is explored. In the ventilated thermocline of the subtropical gyre, the meridional temperature gradient is mapped continously to a corresponding vertical profile, essentially independently of (sufficiently small) diffusivity. Below this, as the vertical diffusivity tends to zero, the mapping becomes discontinuous and is concentrated in thin diffusive layers or internal thermoclines. It is shown that the way in which the thickness of the main internal thermocline (i.e., the diffusive lower part of the main thermocline), and the meridional overturning circulation, scales with diffusivity differs according to the presence or absence of a wind stress. For realistic parameter values, the ocean is in a scaling regime in which wind effects are important factors in the scaling of the thermohaline circulation, even for the single hemisphere, flat-bottomed case. It is shown that deep stratification may readily be produced by the combined effects of surface thermodynamic forcing and geometry. The form of the stratification, but not its existence, depends on the diffusivity. Such deep stratification is efficiently produced, even in single-basin, single-hemisphere simulations, in the presence of a partially topographically blocked channel at high latitudes, provided there is also a surface meridional temperature gradient across the channel. For sufficiently simple geometry and topography, the abyssal stratification is a maximum at the height of the topography. In the limit of small diffusivity, the stratification becomes concentrated in a thin diffusive layer, or front, whose thickness appears to scale as the one-third power of the diffusivity. Above and below this diffusive abyssal thermocline are thick, largely adiabatic and homogeneous water masses. In two hemisphere integrations, the water above the abyssal thermocline may be either "intermediate" water from the same hemisphere as the channel, or "deep" water from the opposing hemisphere, depending on whether the densest water from the opposing hemisphere is denser than the surface water at the equatorward edge of the channel. The zonal velocity in the channel is in thermal wind balance, thus determined more by the meridional temperature gradient across the channel than by the wind forcing. If the periodic channel extends equatorward past the latitude of zero wind-stress curl, the poleward extent of the ventilated thermocline, and the surface source of the mode water, both then lie at the equatorial boundary of the periodic circumpolar channel, rather than where the wind stress curl changes sign. C1 Princeton Univ, AOS Program, Princeton, NJ 08544 USA. GFDL, Princeton, NJ USA. RP Vallis, GK (reprint author), Princeton Univ, AOS Program, Princeton, NJ 08544 USA. NR 42 TC 70 Z9 71 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAY PY 2000 VL 30 IS 5 BP 933 EP 954 DI 10.1175/1520-0485(2000)030<0933:LSCAPO>2.0.CO;2 PG 22 WC Oceanography SC Oceanography GA 316DT UT WOS:000087152900010 ER PT J AU Abdulagatov, IM Emirov, SN Tsomaeva, TA Gairbekov, KA Askerov, SY Magomedova, NA AF Abdulagatov, IM Emirov, SN Tsomaeva, TA Gairbekov, KA Askerov, SY Magomedova, NA TI Thermal conductivity of fused quartz and quartz ceramic at high temperatures and high pressures SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article DE ceramics; high pressure; thermal conductivity AB The thermal conductivity of fused quartz and quartz ceramic has been measured over the temperature range of 273-423 K and at pressures up to 400 MPa using a steady-state parallel-plate apparatus. It is an absolute, steady-state measurement device with an operational temperature a range of 273-1273 K and pressure range up to 1500 MPa. High-pressure measurements are made in an atmosphere of argon. The estimated accuracy of the method is about +/-2%. Measurements were performed at four temperatures, namely: 273, 323, 373, and 423 K for pressures up to 400 MPa. Thermal conductivity shows linear dependence on temperature for all the studied isobars. The effect of pressure on the thermal conductivity behavior has been under study. The thermal conductivity of fused quartz was found to increase linearly at a rate of 4 x 10(-4) W/(m K MPa). Temperature coefficient of thermal conductivity is 0.0018 W/(m K-2). The sharp thermal conductivity changes for quartz ceramic at pressures between 0.1 and 100 MPa has been found for all isotherms while for fused quartz pressure the dependence of thermal conductivity is linearly in the whole pressure range studied. The measured values of thermal conductivity for fused quartz at atmospheric pressure are compared with the recommended values from the literature. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Russian Acad Sci, Dagestan Sci Ctr, Inst Geothermal Res, Makhachkala 367030, Dagestan, Russia. RP Abdulagatov, IM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 25 TC 19 Z9 20 U1 1 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD MAY PY 2000 VL 61 IS 5 BP 779 EP 787 DI 10.1016/S0022-3697(99)00268-1 PG 9 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 293NL UT WOS:000085859000018 ER PT J AU Borovskii, GB Stupnikova, IV Antipina, AI Downs, CA Voinikov, VK AF Borovskii, GB Stupnikova, IV Antipina, AI Downs, CA Voinikov, VK TI Accumulation of dehydrin-like-proteins in the mitochondria of cold-treated plants SO JOURNAL OF PLANT PHYSIOLOGY LA English DT Article DE cold stress; cold tolerance; dehydrins; mitochondria; Secale cereale (L.); Triticum aestivum (L.); Zea mays (L.) ID FREEZING-TOLERANCE; LOW-TEMPERATURE; STRESS PROTEIN; ABSCISIC-ACID; DEHYDRATION; EXPRESSION; FAMILY; DIFFER; WCS120 AB A number of proteins have been found to accumulate in plants during cold tolerance. One class of cold proteins that is associated with cold tolerance acclimation is the glycine-rich, hydrophilic, D-II LEA (late embryogenesis abundant) proteins known as dehydrins. Several members of the dehydrin-class of proteins are known to associate with the nucleus, in the cytosol, and with the plasma membrane. Dehydrins that localise with the mirochondria have not been found. We provide evidence that two dehydrin-like proteins (dlps) accumulate in the mitochondria only after low temperature treatment. We also provide evidence for a positive correlation between the relative accumulation of these proteins in the mitochondria in response to cold stress and relative cold tolerance of several species of plants. C1 Russian Acad Sci, Inst Plant Physiol & Biochem, Irkutsk 664033, Russia. US Natl Ocean & Atmospher Adm, Marine Biotechnol Div, Charleston, SC 29412 USA. RP Russian Acad Sci, Inst Plant Physiol & Biochem, Irkutsk 33,POB 1243, Irkutsk 664033, Russia. EM physgen@sifibr.irk.ru RI Borovskii, Gennadii/A-5147-2016 OI Borovskii, Gennadii/0000-0002-5089-5311 NR 26 TC 30 Z9 32 U1 0 U2 4 PU ELSEVIER GMBH, URBAN & FISCHER VERLAG PI JENA PA OFFICE JENA, P O BOX 100537, 07705 JENA, GERMANY SN 0176-1617 EI 1618-1328 J9 J PLANT PHYSIOL JI J. Plant Physiol. PD MAY PY 2000 VL 156 IS 5-6 BP 797 EP 800 PG 4 WC Plant Sciences SC Plant Sciences GA 330UU UT WOS:000087980200034 ER PT J AU Toggweiler, JR Bjornsson, H AF Toggweiler, JR Bjornsson, H TI Drake Passage and palaeoclimate SO JOURNAL OF QUATERNARY SCIENCE LA English DT Article DE Antarctic Circumpolar Current (ACC); ocean conveyor; coupled ocean circulation model; water planet model ID SCALE WATER MASSES; WORLD OCEAN; MODEL; CIRCULATION; SALINITY; ICE AB The effect of Drake Passage on the Earth's climate is examined using an idealised coupled model. It is found that the opening of Drake Passage cools the high latitudes of the southern hemisphere by about 3 degrees C and warms the high latitudes of the northern hemisphere by nearly the same amount. This study also attempts to determine whether the width and depth of the Drake Passage channel is likely to be an important factor in the thermal response. A deeper channel is shown to produce more southern cooling but the magnitude of the effect is not large. Channel geometry is relatively unimportant in the model because of a haline response that develops when the channel is first opened up. Published in 2000 by John Wiley & Sons, Ltd. C1 NOAA, GFDL, Princeton, NJ 08542 USA. Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RP Toggweiler, JR (reprint author), NOAA, GFDL, POB 308, Princeton, NJ 08542 USA. NR 25 TC 75 Z9 81 U1 2 U2 17 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0267-8179 J9 J QUATERNARY SCI JI J. Quat. Sci. PD MAY PY 2000 VL 15 IS 4 BP 319 EP 328 DI 10.1002/1099-1417(200005)15:4<319::AID-JQS545>3.0.CO;2-C PG 10 WC Geosciences, Multidisciplinary; Paleontology SC Geology; Paleontology GA 330RT UT WOS:000087975500003 ER PT J AU Becker, DA AF Becker, DA TI 30 years of reactor characterization on the NBSR SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH AB The NIST nuclear reactor irradiation facilities used for neutron activation analysis have been well characterized for absolute neutron flux measurements, variations within each irradiation facility, neutron energy measurements of each facility, and temperature and pressure measurements. This has been accomplished with various sample materials and under a range of conditions including biological samples inside of sealed quartz ampoules, and for radiation damage measurements on the polyethylene rabbits used for all pneumatic tube irradiations. As a result of all these measurements, initiated in 1969 and still continuing, the NBSR irradiation facilities have become the most highly characterized NAA irradiation facilities in the world. This paper describes the methods and techniques developed and used for characterization of the NBSR irradiation facilities. C1 Natl Inst Stand & Technol, Nucl Methods Grp, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Becker, DA (reprint author), Natl Inst Stand & Technol, Nucl Methods Grp, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 9 TC 8 Z9 8 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD MAY PY 2000 VL 244 IS 2 BP 361 EP 365 DI 10.1023/A:1006735609177 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GK UT WOS:000088410600022 ER PT J AU Chen-Mayer, HH Mackey, EA Paul, RL Mildner, DFR AF Chen-Mayer, HH Mackey, EA Paul, RL Mildner, DFR TI Quantitative prompt gamma analysis using a focused cold neutron beam SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH AB We report the first quantitative results using a focused cold neutron beam for prompt gamma activation analysis (PGAA). We have measured the prompt gamma signal from known Fe, Cr, Ti, B, and Cd specimens in the focusing geometry, from which we determine the sensitivities for these elements by the method of standard addition. Furthermore, we show results of measurements for homogeneous standard reference materials (boron in SRM 611 glass, and iron and chromium in a steel alloy SRM 160b) to verify the sensitivities determined. Finally, we present a position-dependent study of the Cr to Fe mass ratio in an industrial material, taking advantage of the narrowly focused beam. Existing problems for achieving routine quantitative analysis using the focused beam and suggestions for future directions are discussed. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Chen-Mayer, HH (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 2 TC 6 Z9 6 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD MAY PY 2000 VL 244 IS 2 BP 391 EP 397 DI 10.1023/A:1006747911903 PG 7 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GK UT WOS:000088410600027 ER PT J AU En, Z Brenizer, JS Hosticka, B Becker, DA AF En, Z Brenizer, JS Hosticka, B Becker, DA TI Use of nuclear track detection technique to study boron and nitrogen distributions in alloys SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH AB The paper is devoted to determination of boron and nitrogen in metallic materials by nuclear track techniques for the case of high background in radiograms. The method is based on the detection of the B-10(n,alpha)Li-7 and N-14(n,p)C-14 reaction products with plastic track detectors exposed to a neutron flux in a close contact with the samples analyzed. When determining boron, high background can arise due to fast neutron interactions with hydrogen existing in the detector material and with matrix elements of the sample. In the case of nitrogen determination, high background is usually associated with a presence of boron in metals and alloys, alpha tracks of which strongly interfere with proton tracks from the N-14(n,p)C-14 reaction. The feasibility for measurement of micro-concentrations of boron as well as nitrogen determination in the presence of boron has been studied. C1 Uzbek Acad Sci, Inst Nucl Phys, Tashkent 702132, Uzbekistan. Univ Virginia, Dept Mech Aerosp & Nucl Engn, Charlottesville, VA 22903 USA. NIST, Div Analyt Chem, Nucl Methods Grp, Gaithersburg, MD 20899 USA. RP En, Z (reprint author), Uzbek Acad Sci, Inst Nucl Phys, Tashkent 702132, Uzbekistan. NR 7 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD MAY PY 2000 VL 244 IS 2 BP 435 EP 439 DI 10.1023/A:1006716500517 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GK UT WOS:000088410600034 ER PT J AU George, WL Hagedorn, JG Devaney, JE AF George, WL Hagedorn, JG Devaney, JE TI IMPI: Making MPI interoperable SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE conformance testing; distributed processing; interoperable; message passing; MPI; parallel processing AB The Message Passing Interface (MPI) is the de facto standard for writing parallel scientific applications in the message passing programming paradigm. Implementations of MPI were not designed to interoperate, thereby limiting the environments in which parallel jobs could be run. We briefly describe a set of protocols, designed by a steering committee of current implementors of MPI, that enable two or more implementations of MPI to interoperate within a single application. Specifically, we introduce the set of protocols collectively called Interoperable MPI (IMPI). These protocols make use of novel techniques to handle difficult requirements such as maintaining interoperability among all IMPI implementations while also allowing for the independent evolution of the collective communication algorithms used in IMPI. Our contribution to this effort has been as a facilitator for meetings, editor of the IMPI Specification document, and as an early testbed for implementations of IMPI. This testbed is in the form of an IMPI conformance tester, a system that can verify the correct operation of an IMPI-enabled version of MPI. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP George, WL (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM william.george@nist.gov; john.hagedorn@nist.gov; judith.devaney@nist.gov NR 20 TC 4 Z9 4 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 2000 VL 105 IS 3 BP 343 EP + DI 10.6028/jres.105.035 PG 84 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 337LT UT WOS:000088363200001 PM 27551614 ER PT J AU Bennett, HS AF Bennett, HS TI Technology roadmaps for compound semiconductors SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE analog to digital converters; compound semiconductors; digital video systems; technology roadmaps; wireless communications AB The roles cited for compound semiconductors in public versions of existing technology roadmaps from the National Electronics Manufacturing Initiative, Inc., Optoelectronics Industry Development Association, Microelectronics Advanced Research Initiative on Optoelectronic Interconnects, and Optoelectronics Industry and Technology Development Association (OITDA) are discussed and compared within the context of trends in the Si CMOS industry. In particular, the extent to which these technology roadmaps treat compound semiconductors at the materials processing and device levels will be presented for specific applications. For example, OITDA's Optical Communications Technology Roadmap directly connects the information demand of delivering 100 Mbit/s to the home to the requirement of producing 200 GHz heterojunction bipolar transistors with 30 nm bases and InP high electron mobility transistors with 100 nm gates. Some general actions for progress towards the proposed International Technology Roadmap for Compound Semiconductors (ITRCS) and methods for determining the value of an ITRCS will be suggested. But, in the final analysis, the value added by an ITRCS will depend on how industry leaders respond. The technical challenges and economic opportunities of delivering high quality digital video to consumers provide concrete examples of where the above actions and methods could be applied. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bennett, HS (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM herbert.bennett@nist.gov NR 23 TC 2 Z9 2 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 2000 VL 105 IS 3 BP 429 EP 439 DI 10.6028/jres.105.036 PG 11 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 337LT UT WOS:000088363200002 PM 27551615 ER PT J AU Bennett, HS Filliben, JJ AF Bennett, HS Filliben, JJ TI A systematic approach for multidimensional, closed-form analytic modeling: Minority electron mobilities in Ga1-xAlxAs heterostructures SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE electron mobilities; melding functions; regression analyses; standard deviations ID P-TYPE GAAS; GALLIUM ALUMINUM ARSENIDE AB A significant, practical challenge, which arises in developing computationally efficient physical models for use in computer simulations of microelectronic and optoelectronic devices (for example, transistors in digital cellular phones and lasers in optical networks, respectively), is to represent vast amounts of numerical data for transport properties in two or more dimensions in terms of closed form analytic expressions. In this paper, we present a general methodology to achieve the above goal for a class of numerical data in a bounded two-dimensional space. We then apply this methodology to obtain a closed-form analytic expression for the minority electron mobilities at 300 K in p-type Ga1-xAlxAs as functions of the acceptor density N-A between 10(16) cm(-3) and 10(20) cm(-3) and the mole fraction of AlAs x between 0.0 and 0.3. This methodology and its associated principles, strategies, regression analyses, and graphics are expected to be applicable to other problems beyond the specific case of minority mobilities addressed in this paper. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bennett, HS (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM herbert.bennett@nist.gov; james.filliben@nist.gov NR 23 TC 5 Z9 5 U1 0 U2 0 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAY-JUN PY 2000 VL 105 IS 3 BP 441 EP 452 DI 10.6028/jres.105.037 PG 12 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 337LT UT WOS:000088363200003 PM 27551616 ER PT J AU Santoro, A Natali Sora, I Huang, Q AF Santoro, A Natali Sora, I Huang, Q TI Bond valence analysis of BaRuO3 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE barium ruthenate; bond valence method; sphere packing geometry ID INORGANIC CRYSTAL-STRUCTURES; MAGNETIC-STRUCTURES; PREDICTION; PARAMETERS AB The crystal structure of BaRuO3 has been derived by the bond valence method and sphere packing geometry using only the information obtained from the indexing of a ponder pattern of the compound. The structural parameters derived in this may give calculated bond distances that agree with those measured experimentally to within 0.02 Angstrom. Since the Ba-O and Ru-O distances that completely satisfy the valence requirements of the atoms are incommensurate under the constraints imposed by the geometry of the structure, the Ba-O and Ru-O bonds of the final model are, on the average, compressed and stretched, respectively. iis a result of this analysis it is found that the valences of the two crystallographically independent Ru atoms in the asymmetric unit are very nearly equal. The structure of BaRuO3 is formed by units of three face-sharing RuO6 octahedra, connected to one another by corner sharing, The oxygen atom of the shared faces in each unit are pulled together, thus providing a "shielding effect" that reduces the Ru-Ru interactions. (C) 2000 Academic Press. C1 Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Brescia, INFM, I-25123 Brescia, Italy. Univ Brescia, Dept Chem & Phys Engn & Mat, I-25123 Brescia, Italy. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Santoro, A (reprint author), Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI Natali Sora, Isabella/C-8357-2011 NR 21 TC 17 Z9 18 U1 0 U2 7 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD MAY PY 2000 VL 151 IS 2 BP 245 EP 252 DI 10.1006/jssc.2000.8647 PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 314KK UT WOS:000087054800011 ER PT J AU Peter, S Altorfer, F Buhrer, W Lutz, HD AF Peter, S Altorfer, F Buhrer, W Lutz, HD TI Sr(OH)Br, a metal hydroxide halide with unusual properties SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE strontium hydroxide bromide; Raman spectroscopy; differential scanning calorimetry; disorder of hydroxide ions; H/D isotopic effects; protonic conductivity ID RAMAN-SPECTROSCOPY; IR; SPECTRA AB The disorder of the hydroxide ions of the cubic polymorph of strontium hydroxide bromide Sr(OH)Br(cP16) between the two OH- ion positions I and II has been studied by differential scanning calorimetry (DSC), impedance spectroscopy (electric conductivity), and temperature-dependent Raman spectroscopy (90-630 K). We found that the OH- position I, which is involved in weak trifurcated O-H ... Br hydrogen bonds (nu(OH) = 3543 cm(-1) at 298 K), is depopulated with increasing temperature in favour of OH- position II, where the OH- ions form stronger linear hydrogen bonds (nu(OH) = 3492 cm(-1)). The O ... Br distance of the latter bond decreases from 10 to 780 K by about 5 pm and, hence, the strength of the respective hydrogen bend increases. This is obviously the reason for the change of the population ratio OH- (II)/OH- (I) with increasing temperature, as revealed from both neutron diffraction and Raman spectroscopic datal e.g., 0.08 at 10 K and 0.34 at 780 K (neutron data). For the deuterated compound, these ratios are smaller because in the case of linear hydrogen bonds (OH- II) the strength of D bonds is somewhat greater than that of H bonds and vice versa in the case of trifurcated bonds (OH- I). This is caused by the different zero-point vibrational amplitudes of the respective librational modes. At elevated temperatures, Sr(OH)Br displays large protonic conductivity a with an activation energy of conduction of 60.5 kJ mol(-1) (500-670 K), exceeding sigma > 10(-2) Ohm(-1) cm(-1) above 700 K after a precipitous increase of sigma by 2 orders of magnitude at about 673 K, As shown from the half-widths of the Raman bands the dynamics of local motions of the OH- ions is at least 1 order of magnitude faster than the macroscopic diffusion processes, (C) 2000 Academic Press. C1 Univ Siegen, D-57068 Siegen, Germany. Paul Scherrer Inst, Neutron Scattering Lab, CH-5232 Villigen, Switzerland. ETH Zurich, CH-5232 Villigen, Switzerland. Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Peter, S (reprint author), Univ Siegen, D-57068 Siegen, Germany. NR 15 TC 5 Z9 5 U1 0 U2 9 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD MAY PY 2000 VL 151 IS 2 BP 267 EP 271 DI 10.1006/jssc.2000.8650 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 314KK UT WOS:000087054800014 ER PT J AU Subramanian, MA Li, D Duan, N Reisner, BA Sleight, AW AF Subramanian, MA Li, D Duan, N Reisner, BA Sleight, AW TI High dielectric constant in ACu(3)Ti(4)O(12) and ACu(3)Ti(3)FeO(12) phases SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID PEROVSKITE AB High dielectric constants have been found in oxides of the type ACu(3)Ti(4)O(12). The most exceptional behavior is exhibited by CaCu3Ti4O12, which shows a dielectric constant at 1 kHz of about 12,000 that is nearly constant from room temperature to 300 degrees C, The cubic structure of these materials is related to that of perovskite (CaTiO3), but the TiO6 octahedra are tilted to produce a square planar environment for Cu2+. The CaCu3Ti4O12 structure down to 35 K has been examined by neutron powder diffraction. The structure remains cubic and centric, Most compositions of the type A(2/3)Cu(3)Ti(4)O(12) (A = trivalent rare earth or Bi) show dielectric constants above 1000, The dielectric properties of isostructural compounds of the type ACu(3)Ti(3)FeO(12) are also presented. (C) 2000 Academic Press. C1 Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. Oregon State Univ, Dept Chem, Corvallis, OR 97331 USA. Natl Inst Stand & Technol, NIST Ctr Neutron Diffract, Gaithersburg, MD 20899 USA. RP Subramanian, MA (reprint author), Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. OI Reisner, Barbara/0000-0003-3160-0351 NR 6 TC 1188 Z9 1234 U1 13 U2 138 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD MAY PY 2000 VL 151 IS 2 BP 323 EP 325 DI 10.1006/jssc.2000.8703 PG 3 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 314KK UT WOS:000087054800023 ER PT J AU Andrews, E Saxena, P Musarra, S Hildemann, LM Koutrakis, P McMurry, PH Olmez, I White, WH AF Andrews, E Saxena, P Musarra, S Hildemann, LM Koutrakis, P McMurry, PH Olmez, I White, WH TI Concentration and composition of atmospheric aerosols from the 1995 SEAVS experiment and a review of the closure between chemical and gravimetric measurements SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article; Proceedings Paper CT Air-and-Waste-Management-Association Specialty Conference on Visual Air Quality, Aerosols, and Global Radiation Balance CY SEP 09-12, 1997 CL BARTLETT, NEW HAMPSHIRE SP Air & Waste Management Assoc ID RESOLUTION GAS-CHROMATOGRAPHY; LOS-ANGELES BASIN; ORGANIC AEROSOL; DESCRIPTIVE ANALYSIS; SHENANDOAH VALLEY; SEASONAL TRENDS; WATER ACTIVITY; UNITED-STATES; PARTICLES; VISIBILITY AB We summarize the results from the various measurements and the inter-sampler comparisons from Southeastern Aerosol and Visibility Study (SEAVS), a study with one of its objectives to test for closure among chemical, gravimetric and optical measurements of atmospheric aerosol particles. Sulfate and organics are the dominant components of the SEAVS fine particles (nominally, particles with aerodynamic diameter less than or equal to 2.5 mu m) but between 28 and 42% (range over various samplers) of the gravimetrically measured total fine particle concentration is unidentified by the chemical measurements. Estimates of water associated with inorganic components and measurement imprecision do not totally explain the observed difference between gravimetric and chemical measurements. We examine the theoretical and empirical basis for assumptions commonly made in the published literature to extrapolate total fine particle concentration on the basis of chemical measurements of ions, carbon and elements. We then explore the more general question of closure using the SEAVS data as well as data from other, similar studies reported in the literature. In so combining the SEAVS measurements with Other similar studies, we find a strong association between organic carbon and the unidentified component, that is, the fraction of the total fine particle concentration not identified by chemical measurements. We offer several tenable hypotheses for the relationship between the organic and unidentified components that deserve to be tested in future work. Specifically, we hypothesize that (1) errors in the sampling and analysis of organic carbon; (2) estimates of organic mass from measurements of organic carbon; and/or (3) water absorption by organics may all contribute to the observed relationship. C1 Elect Power Res Inst, Palo Alto, CA 94303 USA. Stanford Univ, Dept Civil Engn, Stanford, CA 94305 USA. Harvard Univ, Sch Publ Hlth, Boston, MA 02115 USA. Univ Minnesota, Dept Mech Engn, Minneapolis, MN 55455 USA. MIT, Nucl Reactor Lab, Cambridge, MA 02139 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. RP Andrews, E (reprint author), NOAA, Boulder, CO 80303 USA. RI McMurry, Peter/A-8245-2008; OI McMurry, Peter/0000-0003-1609-5131; White, Warren H/0000-0001-7323-7867 NR 65 TC 97 Z9 103 U1 3 U2 18 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD MAY PY 2000 VL 50 IS 5 BP 648 EP 664 PG 17 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 313EA UT WOS:000086986300002 PM 10842930 ER PT J AU Pitchford, M Green, M Kuhns, H Farber, RJ AF Pitchford, M Green, M Kuhns, H Farber, RJ TI Characterization of regional transport and dispersion using Project MOHAVE tracer data SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article; Proceedings Paper CT Air-and-Waste-Management-Association Specialty Conference on Visual Air Quality, Aerosols, and Global Radiation Balance CY SEP 09-12, 1997 CL BARTLETT, NEW HAMPSHIRE SP Air & Waste Management Assoc AB Perfluorocarbon tracers were released continuously from several surface locations and one power plant stack location during the winter (30 days) and summer (50 days) intensive studies as part of Project MOHAVE. Tracers were released in winter from the Mohave Power Plant (MPP) and Dangling Rope, UT, located on the shore of Lake Powell near Page, AZ; and in summer from MPP, the Tehachapi Pass between the Mojave Desert and the Central Valley in California, and El Centro, CA, on the California-Mexico border. At the Tehachapi tracer release site six-hour pulses of a separately identifiable perfluorocarbon tracer were released every four days in order to assess the time for the tracer to clear the monitoring network. Daily 24-hr integrated samples were collected at about 30 sites in four states. Limited tracer concentration data with higher time resolution is also available. Graphical displays and analyses identify several regional transport paths, including a convergence zone in the Mojave Desert, the importance of terrain channeling, especially in winter, and a relationship between 24-hr maximum influence function and distance that may prove useful as a scoping tool and to test regional scale air quality models. In winter, Dangling Rope tracer was routinely transported through the entire length of the Grand Canyon, while in summer, MPP tracer was routinely transported over most of Lake Mead. C1 NOAA, Appl Sci Branch, Special Operat & Res Div, Air Resources Lab, Las Vegas, NV 89193 USA. Desert Res Inst, Las Vegas, NV 89132 USA. So Calif Edison Co, Environm Res, Rosemead, CA 91770 USA. RP Pitchford, M (reprint author), NOAA, Appl Sci Branch, Special Operat & Res Div, Air Resources Lab, POB 94227, Las Vegas, NV 89193 USA. RI Kuhns, Hampden/C-3563-2008 NR 15 TC 14 Z9 14 U1 0 U2 0 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD MAY PY 2000 VL 50 IS 5 BP 733 EP 745 PG 13 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 313EA UT WOS:000086986300010 PM 10842938 ER PT J AU Shane, JD Mason, TO Jennings, HM Garboczi, EJ Bentz, DP AF Shane, JD Mason, TO Jennings, HM Garboczi, EJ Bentz, DP TI Effect of the interfacial transition zone on the conductivity of portland cement mortars SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID DC ELECTRICAL-CONDUCTIVITY; IMPEDANCE SPECTROSCOPY; CONCRETE; PASTE; DIFFUSIVITY; ROCK; PERMEABILITY; PERCOLATION; PREDICTION AB The electrical conductivity of portland cement mortars was determined experimentally as a function of the volume fraction of sand and the degree of hydration. The results were analyzed using theoretical models that represent the mortals as three-phase, interactive composites. The three phases are the matrix paste, the aggregate, and the thin interfacial transition zone between the two. The microstructure and properties of the conductive phases (the transition zone and the matrix paste) were determined by a micrometer-scale microstructural model, and were used in conjunction with random-walk algorithms and differential-effective medium theory to determine the overall mortar conductivities. The presence of the transition zone was not found to significantly affect the global electrical conductivity of the mortar. However, there were significant differences in conductivity between the transition zone and matrix pastes when examined on a local level. These differences were found to vary with hydration and were most significant when the degree of hydration was between 0.5 and 0.8. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. RP Shane, JD (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RI Jennings, Hamlin/B-7006-2009; Mason, Thomas/B-7528-2009 NR 43 TC 75 Z9 81 U1 3 U2 16 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 2000 VL 83 IS 5 BP 1137 EP 1144 PG 8 WC Materials Science, Ceramics SC Materials Science GA 319ER UT WOS:000087329000021 ER PT J AU Ravikiran, A AF Ravikiran, A TI Influence of apparent pressure on wear behavior of self-mated alumina SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID STEEL; TRANSITION; MECHANISM; SPEED; MAPS AB Dry sliding wear experiments were conducted on self-mated polycrystalline alumina using a ball-on-disk configuration. Instantaneous nominal pressures and corresponding wear rates were calculated from the measured contact diameter during sliding. Nominal pressure decreased with sliding and the wear rate decreased with decreasing pressure. These results show a good correlation between the nominal pressure and the wear rate, implying the importance of nominal pressure on the wear behavior of alumina. Although such a correlation is not new for metals, it is for ceramics. C1 Univ Karlsruhe, Inst Mat Sci 2, D-76021 Karlsruhe, Germany. Inst Mat Res 1, Res Ctr, D-76021 Karlsruhe, Germany. RP Ravikiran, A (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 13 TC 13 Z9 14 U1 1 U2 3 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 2000 VL 83 IS 5 BP 1302 EP 1304 PG 3 WC Materials Science, Ceramics SC Materials Science GA 319ER UT WOS:000087329000053 ER PT J AU Lu, CG Browning, GL AF Lu, CG Browning, GL TI Four-dimensional variational data assimilation for limited-area models: Lateral boundary conditions, solution uniqueness, and numerical convergence SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID METEOROLOGICAL OBSERVATIONS; MESOSCALE MODEL; ADJOINT; DIFFERENCE AB Mathematical issues arising when applying four-dimensional variational (4DVAR) data assimilation to limited-area problems are studied. The derivation of the adjoint system for the initial-boundary value problem for a general hyperbolic system using the standard variational approach requires that the inflow adjoint variables at an open boundary be zero. However, in general, these "natural" boundary conditions will lead to a different solution than that provided by the global assimilation problem. The impact of using natural boundary conditions when there are errors (on the boundary) in the initial guess on the assimilated initial conditions is discussed. A proof of the uniqueness of the solution for both forward and adjoint equations in the presence of open boundaries at each iteration of the minimization procedure is provided, along with an assessment of the convergence of numerical solutions. Numerical experiments with a simple advection equation support the theoretical analyses. Numerical results show that if observational data are perfect, 4DVAR data assimilation using a limited-area model can produce a reasonable initial condition. However, if there are errors in the observational data at the open boundaries and if natural boundary conditions are assumed, boundary errors can contaminate the assimilated solutions. C1 NOAA, OAR, Forecast Syst Lab, Boulder, CO 80303 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. RP Lu, CG (reprint author), NOAA, OAR, Forecast Syst Lab, Boulder, CO 80303 USA. NR 17 TC 3 Z9 6 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 1 PY 2000 VL 57 IS 9 BP 1341 EP 1353 DI 10.1175/1520-0469(2000)057<1341:FDVDAF>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 312NT UT WOS:000086949900010 ER PT J AU Xu, Q Liu, M Westphal, DL AF Xu, Q Liu, M Westphal, DL TI A theoretical study of mountain barrier jets over sloping valleys SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID LOW-LEVEL JET; COASTAL OROGRAPHY; GAP WINDS; COLD; LAYER; FRONTOGENESIS; CALIFORNIA; FRONTS; ALASKA; STORM AB A shallow-water model is developed to examine the dynamics of mountain-barrier jets over a mesoscale sloping valley between two mountain ridges. In this model, the cold air trapped in the valley is represented by a shallow-water layer that is coupled with the upper-layer flow through a free-slip interface. The pressure gradient exerted from the upper layer plus the pressure gradient generated by the sloping cold layer itself drive the cold air down the valley forming a jet against the surface friction. In the cross-valley direction, the jet-induced Coriolis force is balanced by the pressure gradient force. For a given cross-valley terrain profile, the solution is controlled by eight dimensional environmental parameters. In the nondimensional space, the solution is controlled only by three parameters: the Froude number modified by the ratio between the valley width and the Rossby radius of deformation, the surface drag coefficient normalized by the ratio between the valley depth and the inertial radius, and the upper-layer cross-valley pressure gradient scaled by the lower-layer along-valley pressure gradient. Analytical solutions are obtained for a given cross-valley terrain profile, and the results quantify the dependence of the jet intensity and cross-valley structure on the environmental parameters. The theoretical results are also compared with numerical model simulations. C1 USN, Res Lab, Monterey, CA USA. RP Xu, Q (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 36 TC 2 Z9 2 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 1 PY 2000 VL 57 IS 9 BP 1393 EP 1405 DI 10.1175/1520-0469(2000)057<1393:ATSOMB>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 312NT UT WOS:000086949900013 ER PT J AU Gougousi, T Xu, YH Kidder, JN Rubloff, GW Tilford, CR AF Gougousi, T Xu, YH Kidder, JN Rubloff, GW Tilford, CR TI Process diagnostics and thickness metrology using in situ mass spectrometry for the chemical vapor deposition of W from H-2/WF6 SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID REAL-TIME PROCESS; TUNGSTEN; SILICON; REDUCTION; SIH4 AB Quadrupole mass spectrometry has been used to monitor reactant and product partial pressures in a selective W chemical vapor deposition process. A 4/1H(2)/WF6 molar reactant ratio was used to produce W films on Si wafers, at 67 Pa (0.5 Torr) total pressure, and for wafer temperatures around 400 degrees C. A relatively fast response time (similar to 4 s) sensor system sampled gas directly from a commercial Ulvac ERA-1000 reactor in order to minimize the effect of wall reactions. The signal from the volatile HF product, integrated over the deposition cycle, and corrected fur contributions from reactions in the ion-source region of the quadrupole and for sensor drifts, was found to vary linearly with the weight of the W film deposited, to within an uncertainty of similar to 7%. This provides the basis for real-time, noninvasive thickness metrology to drive process control. Depiction of both H-2 and WF6 reactants was observed. The time integral of the H-2 reactant depletion was also linearly related to the film weight, though the data exhibited a somewhat larger scatter due to the low conversion efficiency of the process. In addition, volatile SiF4 and SiHF3 products of the initial rapid W nucleation reaction on the Si surface were clearly observed, indicating that initial surface conditions may bt: monitored in real time under selective growth conditions. (C) 2000 American Vacuum Society. [S0734-211X(00)08103-8]. C1 Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NIST, Proc Measurement Div, Gaithersburg, MD 20899 USA. RP Rubloff, GW (reprint author), Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA. RI Rubloff, Gary/D-4142-2009; Gougousi, Theodosia/C-8156-2014 OI Rubloff, Gary/0000-0002-1901-3982; NR 19 TC 18 Z9 18 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 2000 VL 18 IS 3 BP 1352 EP 1363 DI 10.1116/1.591478 PG 12 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 325AM UT WOS:000087654200040 ER PT J AU Ramanath, G Greene, JE Petrov, I Baker, JE Allen, LH Gillen, G AF Ramanath, G Greene, JE Petrov, I Baker, JE Allen, LH Gillen, G TI Channeling-induced asymmetric distortion of depth profiles from polycrystalline-TiN/Ti/TiN(001) trilayers during secondary ion mass spectrometry SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID SAMPLE ROTATION AB Asymmetric depth profiles of elemental and molecular secondary ions are obtained during secondary ion mass spectrometry analyses of polycrystalline-TiN/Ti/TiN(001) trilayers using a Cs+ ion beam. The sputter-etching rate R and the secondary ion yield Y from TiN(001) layers are strongly dependent on the incidence angle of the primary ion beam. When the azimuthal angle between the incident beam and one of the in-plane [100] directions in TiN(001) is varied from 0 degrees to 40 degrees, R-TiN(001) varies by more than 40% and Y-TiN(001) by nearly a factor of 3, In contrast, for polycrystalline TiN layers, R-polyTiN and Y-polyTiN are invariant With incident beam angle. Channeling of primary ions and secondary recoils through 0.106-nm-wide channels between highly aligned (100) or (010) planes in TiN(001). and the lack of such correlated long-range alignment in polycrystalline TiN, are the: major reasons fur the observed differences. Channeling in the TiN(001) layer results ill a sharp decrease of Y-Ti in the Ti layer immediately prior to the Ti/TiN(001) interface and increases the interface width, thus degrading depth resolution. These profile distortion effects: can be eliminated either by sample rotation during profiling or by using an O-2(+) primary beam. (C) 2000 American Vacuum Society. [S0734-211X(00)01503-1]. C1 Rensselaer Polytech Inst, Dept Mat Sci, Troy, NY 12180 USA. Univ Illinois, Coordinated Sci Lab, Urbana, IL 61801 USA. Univ Illinois, Mat Res Lab, Urbana, IL 61801 USA. Univ Illinois, Dept Mat Sci, Urbana, IL 61801 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Ramanath, G (reprint author), Rensselaer Polytech Inst, Dept Mat Sci, Troy, NY 12180 USA. RI Ramanath, Ganpati/C-1157-2011; Petrov, Ivan/D-4910-2011 OI Ramanath, Ganpati/0000-0002-8718-9760; Petrov, Ivan/0000-0002-2955-4897 NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 2000 VL 18 IS 3 BP 1369 EP 1374 DI 10.1116/1.591387 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 325AM UT WOS:000087654200042 ER PT J AU Bertness, KA AF Bertness, KA TI Smart pyrometry for combined sample temperature and reflectance measurements in molecular-beam epitaxy SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 18th North American Conference on Molecular Beam Epitaxy CY OCT 10-13, 1999 CL BANFF, CANADA ID DISTRIBUTED BRAGG REFLECTORS; GROWTH-RATES; INTERFEROMETRY; SPECTROSCOPY AB Improved accuracy of measurements of semiconductor wafer temperature is demonstrated in a normal-incidence optical reflectance spectroscopy system that has been modified to allow rapid switching between the measurement of wafer reflectance and wafer emission. The resulting optical system is capable of "smart" pyrometry, in which the emissivity is determined each time the temperature is measured. Measurements during heteroepitaxial growth show that the data from smart pyrometry typically differ from those of conventional pyrometry by 5-10 degrees C, and occasionally by as much as 20 degrees C for multilayer structures of AlGaAs and GaAs. Theory, experimental procedures, and calibration procedures are discussed. [S0734-211X(00)05903-5]. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Bertness, KA (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 14 TC 8 Z9 8 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 2000 VL 18 IS 3 BP 1426 EP 1430 DI 10.1116/1.591396 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 325AM UT WOS:000087654200053 ER PT J AU Mirin, RP Silverman, KL Christensen, DH Roshko, A AF Mirin, RP Silverman, KL Christensen, DH Roshko, A TI Narrow photoluminescence linewidths from ensembles of self-assembled InGaAs quantum dots SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 18th North American Conference on Molecular Beam Epitaxy CY OCT 10-13, 1999 CL BANFF, CANADA ID MOLECULAR-BEAM EPITAXY; MU-M; ROOM-TEMPERATURE; COHERENT ISLANDS; GAAS; GROWTH; TRANSITION; SI(001) AB Self-assembled InGaAs quantum dots have been grown using alternating molecular beams of In, Ga, and As-2. The size distribution changes from bimodal to monodisperse as the quantum dots grow larger. Room-temperature photoluminescence experiments on ensembles of these quantum dots show that the emitted intensity remains high as the center wavelength changes from about 1130 to 1345 nm. The linewidths are less than 30 meV for all samples studied, with the narrowest measured linewidth being 18 meV at a peak emission energy of 930.1 meV (1333 nm). [S0734-211X(00)09703-1]. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Mirin, RP (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. OI Mirin, Richard/0000-0002-4472-4655 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 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 2000 VL 18 IS 3 BP 1510 EP 1513 DI 10.1116/1.591415 PG 4 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 325AM UT WOS:000087654200072 ER PT J AU Zhang, JZ AF Zhang, JZ TI The use of pH and buffer intensity to quantify the carbon cycle in the ocean SO MARINE CHEMISTRY LA English DT Article DE pH; buffer intensity; carbon cycle; Redfield ratio; remineralization ID SURFACE SEAWATER; CONSISTENCY; PRECISION; WATER AB pH of seawater is governed by the content of total carbon dioxide and ionic equilibria between hydrogen ion and various inorganic carbon species in seawater. Buffer intensity is defined as a measure of ability of seawater to accommodate addition of acid or base without appreciable pH change. It can be calculated from pH and total carbon dioxide of seawater, pH data in conjunction with buffer intensity can be used to quantify the carbon cycle in the ocean. The total amount of acid that has been released or consumed by any biogeochemical processes can be calculated from the change in pH multiplied by buffer intensity of seawater, dC(H) = d(beta pH). This approach has been used to quantify the remineralization process in the Antarctic Intermediate Water in the South Pacific. Based on the observational data (pH, total carbon dioxide, O-2 and nutrient measurements on P18 cruise), calculated elemental remineralization ratios are 173, 107 and 14.3 for O/P, C/P and N/P, respectively. The dissolution of calcium carbonate accounts for 21.5% of the total carbon released during the remineralization in the Antarctic Intermediate Water. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NOAA, Ocean Chem Div, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA. RP Zhang, JZ (reprint author), NOAA, Ocean Chem Div, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Zhang, Jia-Zhong/B-7708-2008 OI Zhang, Jia-Zhong/0000-0002-1138-2556 NR 37 TC 14 Z9 15 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-4203 J9 MAR CHEM JI Mar. Chem. PD MAY PY 2000 VL 70 IS 1-3 BP 121 EP 131 DI 10.1016/S0304-4203(00)00024-4 PG 11 WC Chemistry, Multidisciplinary; Oceanography SC Chemistry; Oceanography GA 322XG UT WOS:000087534100010 ER PT J AU Burton, BP AF Burton, BP TI Long-range versus short-range interactions and the configurational energies of Ba(B, B ')O-3 and Pb(B, B ')O-3 perovskites SO MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING LA English DT Article; Proceedings Paper CT Workshop on Thermodynamic and Structural Properties of Alloy Materials CY JUN 20-24, 1999 CL ORANJESTAD, NETHERLANDS SP Army Res Off ID WAVE BASIS-SET; DIELECTRIC-PROPERTIES; MOLECULAR-DYNAMICS; SINGLE-CRYSTALS; DISORDER; BA(ZN1/3TA2/3)O-3; FERROELECTRICS; TRANSITION; CERAMICS; BEHAVIOR AB Total energy calculations were performed for three perovskite related ordered supercells in several stoichiometries of A(B, B')O-3; where A is Pb2+ or Ba2+; B is Mg2+, Zn2+, SC3+ or In3+; and B' is Nb5+,Ta5+ or W6+. A striking difference between the Pb and Ba(B, B')O-3 systems is that the differences in total energies for Pb-systems span ranges that are consistently smaller than those of the Ba systems. This indicates a reduction in the energetic barriers to disordering in the Pb-systems, which is consistent with experimental observations of consistently higher transition temperatures in the Ba-systems. This trend is explained as a consequence of enhanced Pb-O bonding to underbonded oxygens in B2+-O-B2+ and B3+-O-B3+ environments. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Div Ceram, Gaithersburg, MD 20899 USA. RP Burton, BP (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Div Ceram, Gaithersburg, MD 20899 USA. NR 43 TC 7 Z9 7 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0965-0393 J9 MODEL SIMUL MATER SC JI Model. Simul. Mater. Sci. Eng. PD MAY PY 2000 VL 8 IS 3 BP 211 EP 219 DI 10.1088/0965-0393/8/3/301 PG 9 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 323LU UT WOS:000087567500002 ER PT J AU Shay, LK Goni, GJ Black, PG AF Shay, LK Goni, GJ Black, PG TI Effects of a warm oceanic feature on Hurricane Opal SO MONTHLY WEATHER REVIEW LA English DT Article ID TROPICAL CYCLONES; CURRENT RESPONSE; ALTIMETER DATA; MOVING STORM; GULF; MEXICO; RINGS; INTENSITY; DYNAMICS; GILBERT AB On 4 October 1995, Hurricane Opal deepened from 965 to 916 hPa in the Gulf of Mexico over a 14-h period upon encountering a warm core ring (\NCR) in the ocean shed by the Loop Current during an upper-level atmospheric trough interaction. Based on historical hydrographic measurements placed within the context of a two-layer model and surface height anomalies (SHA) from the radar altimeter on the TOPEX mission, upper-layer thickness fields indicated the presence of two warm core rings during September and October 1995. As Hurricane Opal passed directly over one of these WCRs, the 1-min surface winds increased from 35 to more than 60 m s(-1), and the radius of maximum wind decreased from 40 to 25 km. Pre-Opal SHAs in the WCR exceeded 30 cm where the estimated depth of the 20 degrees C isotherm was located between 175 and 200 m. Subsequent to Opal's passage, this depth decreased approximately 50 m, which suggests upwelling underneath the storm track due to Ekman divergence. The maximum heat loss of approximately 24 Kcal cm(-2) relative to depth of the 26 degrees C isotherm was a factor of 6 times the threshold value required to sustain a hurricane. Since most of this loss occurred over a period of 14 h, the heat content loss of 24 Kcal cm equates to approximately 20 kW m(-2). Previous observational findings suggest that about 10%-15% of upper-ocean cooling is due to surface heat fluxes. Estimated surface heat fluxes based upon heat content changes range from 1000 to 3000 W m(-2) in accord with numerically simulated surface heat fluxes during Opal's encounter with the WCR. Composited AVHRR-derived SSTs indicated a 2 degrees-3 degrees C cooling associated with vertical mixing in the along-track direction of Opal except over the WCR where AVHRR-derived and buoy-derived SSTs decreased only by about 0.5 degrees-1 degrees C. Thus, the WCR's effect was to provide a regime of positive feedback to the hurricane rather than negative feedback induced by cooler waters due to upwelling and vertical mixing as observed over the Bay of Campeche and north of the WCR. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine & Atmospher Sci, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Natl Ocean & Atmospher Adm, Dept Phys Oceanog, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Natl Ocean & Atmospher Adm, Hurricane Res Div, Miami, FL 33149 USA. RP Shay, LK (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Goni, Gustavo/D-2017-2012 OI Goni, Gustavo/0000-0001-7093-3170 NR 37 TC 291 Z9 307 U1 7 U2 25 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2000 VL 128 IS 5 BP 1366 EP 1383 DI 10.1175/1520-0493(2000)128<1366:EOAWOF>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319QC UT WOS:000087351800009 ER PT J AU Hallberg, R AF Hallberg, R TI Time integration of diapycnal diffusion and Richardson number-dependent mixing in isopycnal coordinate ocean models SO MONTHLY WEATHER REVIEW LA English DT Article ID BOTTOM BOUNDARY-LAYER; ATLANTIC; PARAMETERIZATION; CIRCULATION; SIMULATION AB In isopycnal coordinate ocean models, diapyenal diffusion must be expressed as a nonlinear difference equation. This nonlinear equation is not amenable to traditional implicit methods of solution. but explicit methods typically have a rime step limit of order Delta t less than or equal to h(2)/kappa (where Delta t is the time step, h is the isopyenal layer thickness, and kappa is the diapyenal diffusivity), which cannot generally be satisfied since the layers could be arbitrarily thin. It is: especially important that the diffusion time integration scheme have no such limit if the diapyenal diffusivity is determined by the local Richardson number. An iterative, implicit time integration scheme of diapyenal diffusion in isopyenal layers is suggested. This scheme is demonstrated to have qualitatively correct behavior in the limit of arbitrarily thin initial layer thickness, is highly accurate in the limit of well-resolved layers, and is not significantly more expensive than existing schemes. This approach is also shown to be compatible with an implicit Richardson number-dependent mixing parameterization. and to give a plausible simulation of an entraining gravity current with parameters like the Mediterranean Water overflow through the Straits of Gibraltar. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. RP Hallberg, R (reprint author), Princeton Univ, NOAA, GFDL, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. NR 21 TC 66 Z9 67 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2000 VL 128 IS 5 BP 1402 EP 1419 DI 10.1175/1520-0493(2000)128<1402:TIODDA>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319QC UT WOS:000087351800011 ER PT J AU Mo, KC AF Mo, KC TI Intraseasonal modulation of summer precipitation over North America SO MONTHLY WEATHER REVIEW LA English DT Article ID OUTGOING LONGWAVE RADIATION; CENTRAL UNITED-STATES; LOW-LEVEL JET; OSCILLATIONS; TROPICS; SCALE AB The intraseasonal rainfall variability over North America is examined using singular spectrum analysis (SSA) and composites of outgoing longwave radiation anomalies (OLRAs). 200-hPa divergence and a gridded rainfall dataset over the United States. The evolution of the Arizona and New Mexico (AZNM) monsoon based on composites indicates that rainfall anomalies propagate eastward from the North Pacific through AZNM. the Great Plains, to the eastern United States, During summer, the wet and dry periods of the AZNM monsoon are modulated by an oscillatory mode with a period of 22-25 days (22-day mode). This is also the dominant mode associated with rainfall events over the Great Plains, The influence of the Madden Julian Oscillation (MJO) on the AZNM monsoon is secondary. The strongest impact of the MJO is on precipitation Mexico. SSA performed on the 200-hPa divergence and OLRAs averaged over Mexico show only one oscillatory mode with a period of about 36-40 days. The 22-25-day mode also exists in the vertically integrated moisture fluxes over the Great Plains. During the wet periods of the AZNM monsoon, more moisture is transported ti om both the Gulf of Mexico and the Gulf of California to AZNM. The situation reverses when the oscillation reaches the other phase. The 22-day mode is linked to tropical convection. when rainfall associated with the 22-day mode travels eastward from AZNM to the Great Plains, the OLRA composites show westward propagating waves just north of the equator. When enhanced convection reaches the western Pacific, rainfall diminishes over AZNM. When convection in the western Pacific is suppressed and enhanced convection is located in the central Pacific, rainfall intensifies over AZNM. C1 NOAA, NWS, NCEP, Climate Predict Ctr, Camp Springs, MD 20746 USA. RP Mo, KC (reprint author), NOAA, NWS, NCEP, Climate Predict Ctr, 5200 Auth Rd, Camp Springs, MD 20746 USA. NR 22 TC 71 Z9 74 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2000 VL 128 IS 5 BP 1490 EP 1505 DI 10.1175/1520-0493(2000)128<1490:IMOSPO>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319QC UT WOS:000087351800016 ER PT J AU Cione, JJ Black, PG Houston, SH AF Cione, JJ Black, PG Houston, SH TI Surface observations in the hurricane environment SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE UNSATURATED DOWNDRAFTS; BOUNDARY-LAYER; SQUALL-LINE; TEMPERATURE; RAINBAND AB Composite analyses of marine surface observations from 37 hurricanes between 1975 and 1998 show that the difference between the sea surface temperature and the surface air temperature significantly increases just outside the hurricane inner core. This increase in the sea-air contrast is primarily due to a reduction in surface air temperature and is more likely to occur when sea temperatures are at least 27 degrees C. Results show that 90% of the observed cooling occurs 3.25 degrees-1.25 degrees latitude from the hurricane center. well outside the region of strongest surface winds. Since surface pressure only decreases 3 mb over this interval, the similar to 2 degrees C drop in air temperature is not a result of adiabatic expansion. For the subset of observations that contained moisture measurements, surface specific humidity decreased 1.2 g kg(-1) 4.5 degrees-1.75 degrees latitude from the storm center. This Ending suggests that the observed reduction in surface air temperature is not simply a result of near-surface evaporation from sea spray or precipitation. An alternate explanation may be that outside the hurricane inner core, unsaturated convective downdrafts act to dry and evaporatively cool the near-surface environment. Between 3.25 degrees and 1.25 degrees radius, composite analyses show that low-level inflow is not isothermal. surface moisture is not constant, and the near-surface environment is not in thermodynamic equilibrium with the sea. Calculations based on these observations show that theta, decreases between 4.0 degrees and 1.25 degrees radius and then quickly rises near the inner core as surface pressures fall and specific humidity increases. Surface fluxes of heat and moisture are also observed to significantly increase near the inner core. The largest increase in surface sensible heat Aux occurs radially inward of 1.5 degrees. where surface winds are strong and sea-air temperature contrasts are greatest. As a result, the average Bowen ratio is 0.20 similar to 0.5 degrees radius from the composite storm center This increase in sensible heat flux (in conjunction with near-saturated conditions at low to midlevels) may help explain why average surface air temperatures inside 1.25 degrees radius remain relatively constant, despite the potential for additional cooling from evaporation and adiabatic expansion within the high wind inner core. C1 NOAA, Hurricane Res Div, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Cione, JJ (reprint author), NOAA, Hurricane Res Div, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI CIONE, JOSEPH/B-2973-2014 OI CIONE, JOSEPH/0000-0002-2011-887X NR 47 TC 70 Z9 72 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAY PY 2000 VL 128 IS 5 BP 1550 EP 1561 DI 10.1175/1520-0493(2000)128<1550:SOITHE>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319QC UT WOS:000087351800020 ER PT J AU Handy, EM Rao, MV Holland, OW Jones, KA Chi, PH AF Handy, EM Rao, MV Holland, OW Jones, KA Chi, PH TI Acceptor ion-implantation in SiC SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 10th International Conference on Radioation Effects in Insulators (REI-10) CY JUL 18-23, 1999 CL JENA, GERMANY SP Deutsch Forsch Gemeinsch, Friedrich Schiller Univ Jena, Thruinger Minist Wissensch, Forsch & Kultur, Elsevier Sci BV, Amsterdam, High Voltage Engn Europa BV, Amersfoort, Carl Zeiss Jena GmbH, Jena, Jenoptik AG, Jena, Layertec GmbH, Mellingen, VACOM GmbH, Jena, JENION, Jena, PINK GmbH, Wertheim DE SiC; ion-implantation; acceptors; annealing; activation AB Single and multiple energy Al, B and Ga ion-implantations were performed into n-type 6H-SiC epitaxial layers. Empirical formulae for the range statistics of the implant depth distributions in the energy range 50 keV-4 MeV were developed by analyzing the experimental secondary ion mass spectrometry (SIMS) implant depth profiles. The Al and Ga implants were electrically activated at an annealing temperature of 1500 degrees C, but the B implants required an annealing temperature of 1650 degrees C. In this study annealings were performed by using AlN or graphite encapsulant. The Al and Ga implants are thermally stable but the B implants showed redistribution during annealing. (C) 2000 Elsevier Science B.V. All rights It served. C1 George Mason Univ, Fairfax, VA 22030 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. USA, Res Lab, Adelphi, MD 20783 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Rao, MV (reprint author), George Mason Univ, Fairfax, VA 22030 USA. NR 10 TC 1 Z9 1 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAY PY 2000 VL 166 BP 395 EP 398 DI 10.1016/S0168-583X(99)00867-8 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 320VU UT WOS:000087422200068 ER PT J AU Liu, PC AF Liu, PC TI Is the wind wave frequency spectrum outdated SO OCEAN ENGINEERING LA English DT Article DE wind waves; wave spectrum; spectrum analysis; wavelets; wavelet transform; stationarity; non-stationarity; wind wave growth AB This paper presents a detailed examination of the practice of using the frequency spectrum to characterize wind waves. In particular, the issue of stationarity and Gaussian random process in connection with wind wave studies is addressed. We describe a test for nonstationarity based on the wavelet spectrum. When this test is applied to wind wave time series, the results significantly diverge from those expected for a Gaussian random process, thus casting critical doubts on the conventional concept of the wind wave frequency spectrum. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Liu, PC (reprint author), NOAA, Great Lakes Environm Res Lab, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. NR 13 TC 45 Z9 48 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0029-8018 J9 OCEAN ENG JI Ocean Eng. PD MAY PY 2000 VL 27 IS 5 BP 577 EP 588 DI 10.1016/S0029-8018(98)00074-2 PG 12 WC Engineering, Marine; Engineering, Civil; Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 241QJ UT WOS:000082893800007 ER PT J AU Hoard, RJ Eichmiller, FC Parry, EE Giuseppetti, AA AF Hoard, RJ Eichmiller, FC Parry, EE Giuseppetti, AA TI Edge-bevel fracture resistance of three direct-filling materials SO OPERATIVE DENTISTRY LA English DT Article ID CORROSION AB Edge strength is defined in this study as the resistance to fracture of the beveled extension normally located at the cavosurface margin of a dental restoration. The edge strength of direct-filling alloy restorations plays an important role in maintaining the integrity of margins at tooth-alloy interfaces during functional loading. The purpose of this study was to determine the relative strength of an experimental consolidated silver material in comparison to other direct filling materials. The method used was designed as a simulation for relative edge-strength clinical properties. Stainless steel dies were formed from disks 5 mm thick, each with a centered hole tapered (1/48) toward the bottom side of the disk A 41 degrees bevel, 0.5 mm wide as viewed from above, was placed on the top-side of the disk Dispersalloy (D) or Unison (U) amalgam, Z-100 composite (C), hand-consolidated silver powder (HAg), or pneumatically consolidated silver powder (PAg) was used to fill the die opening. Excess was polished from both sides of the disk with 600-grit abrasive paper. The sample was loaded from the beveled side with a 3 mm-in-diameter flat-ended plunger at a rate of 1.0 mm/minute until failure. Failure load and total energy to failure were recorded and compared. Tukey's multiple comparison test (p<0.05) ranked the materials (U)>(HAg)>(D)> (PAg)>(C) for fracture strength and (NAg)(D)> (U)>(PAg)>(C) for fracture energy. C1 Natl Inst Stand & Technol, Paffenbarger Res Ctr, Amer Dent Assoc Hlth Fdn, Gaithersburg, MD 20899 USA. RP Hoard, RJ (reprint author), Univ Calif Los Angeles, Sch Dent, Div Restorat Dent, Los Angeles, CA 90095 USA. FU NIDCR NIH HHS [P50 DE09322] NR 10 TC 2 Z9 2 U1 0 U2 1 PU OPERATIVE DENTISTRY INC PI INDIANAPOLIS PA INDIANA UNIV SCHOOL DENTISTRY, ROOM S411, 1121 WEST MICHIGAN ST, INDIANAPOLIS, IN 46202-5186 USA SN 0361-7734 J9 OPER DENT JI Oper. Dent. PD MAY-JUN PY 2000 VL 25 IS 3 BP 182 EP 185 PG 4 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 312FE UT WOS:000086931900010 PM 11203814 ER PT J AU Cahn, JW AF Cahn, JW TI Wetting and non-wetting near critical points in solids SO PHYSICA A LA English DT Article DE solid-solid interfaces; wetting; interface and surface thermodynamics ID MODEL; INTERFACES; BOUNDARIES; COHERENT; ALLOYS; MISFIT; PHASE AB A phenomenological qualitative theory of elastic effects is used to examine wetting near critical points in the solid state. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Cahn, JW (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Mail Stop 8555, Gaithersburg, MD 20899 USA. NR 23 TC 11 Z9 12 U1 2 U2 14 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 1 PY 2000 VL 279 IS 1-4 BP 195 EP 202 DI 10.1016/S0378-4371(99)00513-0 PG 8 WC Physics, Multidisciplinary SC Physics GA 310JR UT WOS:000086823200018 ER PT J AU Affolter, J Eichenberger, A Rosse, S Scheuzger, P Leemann, C Martinoli, P AF Affolter, J Eichenberger, A Rosse, S Scheuzger, P Leemann, C Martinoli, P TI Phase and vortex dynamics in Josephson junction arrays with percolative disorder SO PHYSICA B LA English DT Article; Proceedings Paper CT 22nd International Conference on Low Temperature Physics CY AUG 04-11, 1999 CL HELSINKI UNIV TECHNOL, HELSINKI, FINLAND SP Commiss C5 low Temp Phys, Int Union Pure & Appl Phys, Acad Finland, Helsinki Univ Technol, Int Assoc Promot Sci, Oxford Instruments Ltd, FortumCorp, Nokia Grp, Finnair Ltd, Datex Engstrom Ltd, Finnish Phys Soc, Picker Nordstar Ltd, Neuromag ltd, SAP Finland Ltd, Espoo Elect Ltd, Outokumpu Ltd, City Espoo, Finnish Acad Sci & Letters, DCA-Instruments Ltd, Vaisala Ltd HO HELSINKI UNIV TECHNOL DE fractal; Josephson-junction arrays; percolation; vortex excitations AB The AC conductance G of site-diluted Josephson junction arrays close to the percolation threshold was studied over a broad frequency range. As a function of frequency, G exhibits a crossover from a low-frequency Euclidean to a high-frequency fractal regime. At low-frequency the response is dominated by vortices and its temperature dependence is well-described by dynamical extensions of the Kosterlitz-Thouless theory for two-dimensional systems. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Neuchatel, Inst Phys, CH-2000 Neuchatel, Switzerland. Natl Inst Stand & Technol, Boulder, CO USA. RP Martinoli, P (reprint author), Univ Neuchatel, Inst Phys, Rue AL Breguet 1, CH-2000 Neuchatel, Switzerland. RI Eichenberger, Ali/J-3073-2012 NR 5 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD MAY PY 2000 VL 280 IS 1-4 BP 241 EP 242 DI 10.1016/S0921-4526(99)01640-3 PG 2 WC Physics, Condensed Matter SC Physics GA 301WP UT WOS:000086333700067 ER PT J AU Bohn, JL AF Bohn, JL TI Cooper pairing in ultracold K-40 using Feshbach resonances SO PHYSICAL REVIEW A LA English DT Article ID SPIN-POLARIZED LI-6; FERMIONIC ATOMS; SCATTERING LENGTHS; DISPERSION COEFFICIENTS; COLLISIONAL PROPERTIES; DIPOLE TRAP; GAS; STATE; PHOTOASSOCIATION; SUPERFLUID AB We point out that the fermionic isotope K-40 is a likely candidate for the formation of Cooper pairs in an ultracold atomic gas. Specifically, in an optical trap that simultaneously traps the spin states \9/2,- 9/2] and \9/2,-7/2], there exists a broad magnetic-field Feshbach resonance at B = 196(-21)(+9) G that can provide the required strong attractive interaction between atoms. An additional resonance, at B = 191(10)(+5) G, could generate p-wave pairing between identical \9/2,-7/2] atoms. A Cooper-paired degenerate Fermi gas could thus be constructed with existing ultracold-atom technology. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP Bohn, JL (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 35 TC 63 Z9 63 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2000 VL 61 IS 5 BP art. no. EP 053409 DI 10.1103/PhysRevA.61.053409 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 312QD UT WOS:000086953200084 ER PT J AU Bradley, CC McClelland, JJ Anderson, WR Celotta, RJ AF Bradley, CC McClelland, JJ Anderson, WR Celotta, RJ TI Magneto-optical trapping of chromium atoms SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATION; SODIUM ATOMS; COLLISIONS; FREQUENCY; LASERS; COLD; GAS AB We have constructed a magneto-optical trap for chromium atoms. Using trapping light at 425 nm and two repumping lasers tuned to intercombination transitions, over 10(6) atoms were trapped and average densities of over 10(16) m(-3) were obtained. Nonexponential loss of atoms is observed at high densities indicating inelastic collisions between trapped atoms. Over a range of trapping conditions, the density-dependent trap loss rate constant beta is extracted from fluorescence decay curves and found to have values in the range of 10(-15) m(3) s(-1) much larger than is observed in alkali-metal traps. C1 Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP McClelland, JJ (reprint author), Texas Christian Univ, Dept Phys & Astron, Ft Worth, TX 76129 USA. RI McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2000 VL 61 IS 5 BP art. no. EP 053407 DI 10.1103/PhysRevA.61.053407 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 312QD UT WOS:000086953200082 ER PT J AU Holland, MJ DeMarco, B Jin, DS AF Holland, MJ DeMarco, B Jin, DS TI Evaporative cooling of a two-component degenerate Fermi gas SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATION; COLLECTIVE EXCITATIONS; KINETIC-THEORY; ATOMIC GAS; HYDROGEN; SPIN AB We derive a quantum theory of evaporative cooling for a degenerate Fermi gas: with two constituents and show that the optimum cooling trajectory is influenced significantly by the quantum statistics of the particles. The cooling efficiency is reduced at low temperatures due to Pauli blocking of available final states in each binary collision event. We compare the theoretical optimum trajectory with experimental data on cooling a quantum degenerate cloud of potassium-40, and show that temperatures as low as 0.3 times the Fermi temperature can now be achieved. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Holland, MJ (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 29 TC 101 Z9 101 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2000 VL 61 IS 5 BP art. no. EP 053610 DI 10.1103/PhysRevA.61.053610 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 312QD UT WOS:000086953200097 ER PT J AU Porto, JV Kink, I Gillaspy, JD AF Porto, JV Kink, I Gillaspy, JD TI UV light from the ground term of Ti-like ytterbium, tungsten, and bismuth SO PHYSICAL REVIEW A LA English DT Article ID ENERGY DIFFERENCES; TRANSITION; IONS AB We have used an electron-beam ion trap to measure the wavelength of the J = 2-3 magnetic dipole transition in the 3d(4) ground term of Ti-like ytterbium, tungsten, and bismuth. This fills in a gap in previous measurements along this isoelectronic sequence, as well as extending previous work to the highest Z yet. With the addition of our results, measurements of this line now cover a sufficient range of Z to allow an interpolation of reliable wavelength estimates for the unmeasured members of the isoelectronic sequence from Z = 52 to 83. We provide a table of these wavelengths for each member of the sequence in this range, and compare the measured wavelengths to recent calculations. Our results show that a long-standing discrepancy between prediction and experiment disappears in the high-Z limit. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Porto, JV (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 18 TC 34 Z9 34 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 2000 VL 61 IS 5 BP art. no. EP 054501 DI 10.1103/PhysRevA.61.054501 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 312QD UT WOS:000086953200124 ER PT J AU Hobbie, EK Stewart, AD AF Hobbie, EK Stewart, AD TI Internal dynamics and elasticity of confined entropic gels SO PHYSICAL REVIEW E LA English DT Article ID POLYMER-SOLUTIONS; RELAXATION; SCATTERING; COLLOIDS; MIXTURES; GLASSES; MODEL AB The internal dynamics and elasticity of colloidal gels formed via depletion in confined nearly hard-sphere mixtures are studied via particle-tracking measurements of the self part of the van Hove correlation function, which is found to decay exponentially in space and exhibit a scaling in terms of its first moment. The second moment, or mean-square particle displacement, exhibits a stretched-exponential decay to a plateau and provides a measure of the weak elastic modulus of the gel. A Fourier analysis of the real-space probability distribution yields the intermediate scattering function, which at fixed wave vector exhibits a stretched exponential decay to a nonzero plateau, reminiscent of dynamic behavior observed in a broad class of disordered systems. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hobbie, EK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Hobbie, Erik/C-8269-2013 NR 21 TC 4 Z9 4 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 2000 VL 61 IS 5 BP 5540 EP 5544 DI 10.1103/PhysRevE.61.5540 PN B PG 5 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 314RK UT WOS:000087071200015 ER PT J AU Barnes, KA Douglas, JF Liu, DW Bauer, B Amis, EJ Karim, A AF Barnes, KA Douglas, JF Liu, DW Bauer, B Amis, EJ Karim, A TI Influence of generation number on the dewetting of hypergraft poly(2-ethyl-2-oxazoline) films SO POLYMER INTERNATIONAL LA English DT Article; Proceedings Paper CT 2nd Annual Garcia MRSEC University/Industry Workshop CY OCT 25-27, 1998 CL BROOKHAVEN NATL LAB, UPTON, NEW YORK SP Natl Sci Fdn, Cameca Instruments Inc, Sympol Technologies, Collaborative Grp Ltd, Olympus Amer Inc HO BROOKHAVEN NATL LAB DE dewetting; hypercraft polymer; film; foam ID THIN POLYMER-FILMS; MELT RHEOLOGY; SOAP BUBBLES; POLYSTYRENES; MODEL; MICROGELS; PATTERNS; R(2) AB We investigate the influence of polymer branching (generation number G) on the dewetting of hypergraft poly(2-ethyl-2-oxazoline) (PEOX) polymer films from model non-polar synthetic polymer and inorganic substrates. The present study contrasts the cases of a zeroth generation GO hypergraft, which is a comb polymer, and a G2 hypergraft, which resembles a nearly spherical 'microgel' particle. The early stage of dewetting is found to be similar in the GO and G2 films and is largely independent of substrate (entangled polystyrene film or acid-cleaned silica wafer). However, the late stage of dewetting in the G2 films differs significantly from the GO films because of an inhibition of hole coalescence in the intermediate stage of film dewetting. The holes in the G2 hyperbranched films continue to grow in size until they impinge on each other to form a foam-like structure with a uniform 'cell) size. The boundaries of these cells break up and the vertices of the former cellular network retract to form a relatively uniform droplet configuration. In contrast, hole coalescence in the GO films occurs readily, leading to a polydisperse hole size distribution, and the fluid borders of the holes break up to form the non-uniform (Voronoi' droplet configuration normally associated with him dewetting. Similar trends have been observed in the dewetting of linear polymer films where entangled polymers behave similarly to the branched (G2) polymers of the present study. This effect is attributed to the viscoelasticity of the G2 hyperbranched polymer fluid. (C) 2000 Society of Chemical Industry. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Karim, A (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 29 TC 5 Z9 5 U1 0 U2 6 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0959-8103 J9 POLYM INT JI Polym. Int. PD MAY PY 2000 VL 49 IS 5 BP 463 EP 468 PG 6 WC Polymer Science SC Polymer Science GA 314CG UT WOS:000087036200010 ER PT J AU Newby, PE Killoran, P Waldorf, MR Shuman, BN Webb, RS Webb, T AF Newby, PE Killoran, P Waldorf, MR Shuman, BN Webb, RS Webb, T TI 14,000 years of sediment, vegetation, and water-level changes at the Makepeace Cedar Swamp, southeastern Massachusetts SO QUATERNARY RESEARCH LA English DT Article DE hydrologic balance; lake levels; fossil pollen; analog technique; mires; Massachusetts ID EASTERN NORTH-AMERICA; AGE CALIBRATION; UNITED-STATES; POLLEN; CARBONATE; PROGRAM; LAKE AB Data from a transect of four cores collected in the Makepeace Cedar Swamp, near Carver, Massachusetts, record past changes in deposition, vegetation, and water level. Time series of palynological data provide a 14,000-yr record of regional and local vegetation development, a means for biostratigraphic correlation and dating, and information about changes in water level. Differences in records among cores in the basin show that water level decreased at least 1.5 m between similar to 10,800 and 9700 cal yr B,P., after which sediment accumulation was slow and intermittent across the basin for about 1700 yr. Between 8000 and 5600 cal yr B.P,, water level rose similar to 2.0 m, after which slow peat accumulation indicates a low stand about the time of the hemlock decline at 5300 +/- 200 cal yr B.P, Dry conditions may have continued after this time, but by 3200 cal yr B.P., the onset of peat accumulation in shallow cores indicates that water level had risen to close to its highest postglacial level, where it is today, Feat has accumulated across the whole basin since 3200 cal yr B,P, Data from Makepeace and the Pequot Cedar Swamp, near Ledyard, Connecticut, indicate an early Holocene dry interval in southern New England that began 11,500 yr ago near the end of the Younger Dryas interval. The dry conditions prevailed between 10,800 and 8000 cal yr B,P, and coincide with the arrival and later rise to dominance of white pine trees (Pinus strobus) both regionally and near the basins. Our results indicate a climatic cause for the "pine period" in New England. (C) 2000 University of Washington. C1 Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Univ Oregon, Dept Geog, Eugene, OR 97403 USA. NOAA, Climate Diagnost Ctr, Paleoclimatol Program, Boulder, CO 80303 USA. RP Newby, PE (reprint author), Brown Univ, Dept Geol Sci, Box 1846, Providence, RI 02912 USA. NR 50 TC 50 Z9 50 U1 3 U2 8 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0033-5894 J9 QUATERNARY RES JI Quat. Res. PD MAY PY 2000 VL 53 IS 3 BP 352 EP 368 DI 10.1006/qres.1999.2120 PG 17 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 317VC UT WOS:000087246800009 ER PT J AU Gibson-Wilde, D Werne, J Fritts, D Hill, R AF Gibson-Wilde, D Werne, J Fritts, D Hill, R TI Direct numerical simulation of VHF radar measurements of turbulence in the mesosphere SO RADIO SCIENCE LA English DT Article ID WAVE BREAKING SIGNATURES; ENERGY-DISSIPATION RATES; MST RADAR; POLAR MESOSPHERE; SODIUM DENSITIES; OH NIGHTGLOW; ROCKET; INSTABILITY; STATE; FLUCTUATIONS AB We simulate very high frequency (VHF) radar backscatter from turbulent irregularities in the mesosphere and examine the process of calculating hey turbulence parameters from radar Doppler spectral moments. Mesospheric turbulence is represented by a three-dimensional (3-D) direct numerical simulation (DNS) of a turbulent layer generated by Kelvin-Helmholtz instability, which exhibits inertial range turbulence characteristics. A subgrid-scale turbulence advection model is used to parameterize the unresolved small-scale structure of mesospheric temperature, ion species, and electron mixing ratios and to derive the radar backscatter cross sections. Energy and thermal dissipation rates are calculated from the 3-D velocity and temperature derivatives of the DNS. Doppler spectral widths relevant to various mesospheric radar observations are then determined from explicit calculation of spectral moments. Mie then present a comparison between the turbulence parameters calculated from the DNS and those calculated from the Doppler spectral moments. C1 Colorado Res Associates, Boulder, CO 80301 USA. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Gibson-Wilde, D (reprint author), Colorado Res Associates, 3380 Mitchell Lane, Boulder, CO 80301 USA. NR 31 TC 37 Z9 37 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAY-JUN PY 2000 VL 35 IS 3 BP 783 EP 798 DI 10.1029/1999RS002269 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 320AB UT WOS:000087377700011 ER PT J AU Simpson, JJ Hufford, G Pieri, D Berg, J AF Simpson, JJ Hufford, G Pieri, D Berg, J TI Failures in detecting volcanic ash from satellite-based technique SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID SOUFRIERE HILLS VOLCANO; ERUPTION COLUMNS; RADIATIVE-TRANSFER; WATER-VAPOR; MONTSERRAT; CLOUDS; AVHRR AB Immediate and accurate detection of airborne volcanic ash is an operational imperative of the aviation industry, especially jet aircraft. Ash encounters place passengers aboard these aircraft at severe risk and significantly impact, via forced rerouting, both the safety and profit margins of freight carriers due to their limited fuel supply. Moreover the airlines can suffer high economic costs for repair and -replacement of equipment. Operational detection. and tracking of volcanic ash by most national weather services has relied heavily on a split window differencing technique of thermal longwave infrared channels on currently operational satellites. Unfortunately, prior work on volcanic ash defection has not emphasised the dynamical interaction between the erupting volcano and the effects of overlying atmospheric Lr;ater vapor phreatic and phreatomagmatic water sources. Six volcanic ash eruptions from around the globe were chosen for study because they have wide variation in ambient atmospheric water vapor, available ground and surface water and different magma types. Results show that the present differencing technique is not uniformly effective in properly classifying volcanic ash pixels in the satellite scene and often falsely interprets meteorological clouds as volcanic ash clouds and conversely. Moreover it is not always a robust early detector, an operational aviation requirement. Seasonal variability in global integrated atmospheric water vapor coupled with the geographical distribution of currently active volcanoes, suggests the concerns discussed herein with regard to six specific eruptions, have applicability to the global aviation industry. Operational implications are discussed and a strategic proposal is presented on necessary steps to improve detection. (C) Elsevier Science Inc., 2000. C1 Univ Calif San Diego, Scripps Inst Oceanog, Digital Image Anal Lab, La Jolla, CA 92093 USA. Natl Weather Serv, Alaska Reg, Anchorage, AK USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Simpson, JJ (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Digital Image Anal Lab, La Jolla, CA 92093 USA. NR 53 TC 62 Z9 62 U1 1 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAY PY 2000 VL 72 IS 2 BP 191 EP 217 DI 10.1016/S0034-4257(99)00103-0 PG 27 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 307YY UT WOS:000086682800006 ER PT J AU Wight, SA Zeissler, CJ AF Wight, SA Zeissler, CJ TI Direct measurement of electron beam scattering in the environmental scanning electron microscope using phosphor imaging plates SO SCANNING LA English DT Article DE environmental scanning electron microscope; electron scattering; skirt; phosphor imaging plates; photostimulable; luminescence AB Phosphor imaging plate technology has made it possible to directly image the distribution of primary beam electrons and scattered electrons in the environmental scanning electron microscope. The phosphor plate is exposed under electron scattering conditions in the microscope chamber. When processed, the electron intensity distribution is displayed as a digital image. The image is a visual representation of the electron probe and skirt and may provide the basis for a more accurate model. C1 NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Wight, SA (reprint author), NIST, Surface & Microanal Sci Div, 100 Bur Dr,Stop 8371, Gaithersburg, MD 20899 USA. NR 13 TC 7 Z9 7 U1 0 U2 1 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAY-JUN PY 2000 VL 22 IS 3 BP 167 EP 172 PG 6 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 326QX UT WOS:000087747200004 ER PT J AU Suzuki, M Ando, H Higashi, Y Takenaka, H Shimada, H Matsubayashi, N Imamura, M Kurosawa, S Tanuma, S Powell, CJ AF Suzuki, M Ando, H Higashi, Y Takenaka, H Shimada, H Matsubayashi, N Imamura, M Kurosawa, S Tanuma, S Powell, CJ TI Experimental determination of electron effective attenuation lengths in silicon dioxide thin films using synchrotron radiation - I. Data analysis and comparisons SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE effective attenuation length; silicon dioxide; synchrotron radiation; photoemission; inelastic mean free path ID MEAN FREE PATHS; SURFACES; RANGE AB We have measured effective attenuation lengths (EALs) of 140-1100 eV electrons in ultrathin silicon dioxide layers using synchrotron radiation. These EALs were generally smaller than those reported previously, although there was agreement with the values measured by Hochella and Carim (Surf, Sci, Lett, 1988; 197: L260). Our measured EALs were similar to 37% smaller than the corresponding inelastic mean free paths calculated from optical data by Tanuma et al, Part of this difference is believed to be due to uncertainty in measurements of the oxide thickness and the remainder to the effects of elastic electron scattering. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 NTT, Adv Technol Corp, Ctr Mat Dev & Analyt Technol, Atsugi, Kanagawa 2430198, Japan. Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan. Japan Energy Co Ltd, Toda, Saitama 3358503, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Suzuki, M (reprint author), NTT, Adv Technol Corp, Ctr Mat Dev & Analyt Technol, Atsugi, Kanagawa 2430198, Japan. RI Tanuma, Shigeo/H-2681-2011; Shimada, Hiromichi/K-6932-2016 OI Shimada, Hiromichi/0000-0002-0115-7785 NR 21 TC 12 Z9 12 U1 2 U2 3 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD MAY PY 2000 VL 29 IS 5 BP 330 EP 335 DI 10.1002/(SICI)1096-9918(200005)29:5<330::AID-SIA876>3.0.CO;2-G PG 6 WC Chemistry, Physical SC Chemistry GA 317AQ UT WOS:000087201600006 ER PT J AU Shimada, H Matsubayashi, N Imamura, M Suzuki, M Higashi, Y Ando, H Takenaka, H Kurosawa, S Tanuma, S Powell, CJ AF Shimada, H Matsubayashi, N Imamura, M Suzuki, M Higashi, Y Ando, H Takenaka, H Kurosawa, S Tanuma, S Powell, CJ TI Experimental determination of electron effective attenuation lengths in silicon dioxide thin films using synchrotron radiation - II. Effects of elastic scattering SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE XPS; photoemission; quantitative analysis; inelastic mean free path; polarization ID RAY-PHOTOELECTRON-SPECTROSCOPY; MEAN FREE PATHS; POLARIZED X-RAYS; AES; DEPTH; XPS; SOLIDS; RANGE AB The effective attenuation lengths (EALs) of photoelectrons in thin silicon dioxide films on an Si(100) substrate were measured as a function of electron energy using synchrotron radiation as an energy-tunable excitation source. The ratios of EALs to inelastic mean free paths (IMFPs) calculated from optical data were independent of electron energy from 140 to 1000 eV when the analyzer axis was normal to the sample surface and the angle between the incident x-rays and the surface normal was 55 degrees. This result indicates that the effects of elastic electron scattering (in causing the EAL to be less than the corresponding IMFP) were independent of electron energy for this configuration, The EALs measured with normally incident x-rays and electron emission at 55 degrees with respect to the surface normal were larger than EALs for the other configuration, In particular, the difference for the EALs at the two configurations was similar to 25% for electron energies below 200 eV, The angular range suitable for satisfactory angle-resolved analyses with x-ray photoelectron spectroscopy should therefore be limited to <55 degrees when the electron energies are less than similar to 500 eV, Copyright (C) 2000 John Whey & Sons, Ltd. C1 Natl Inst Mat & Chem Res, Tsukuba, Ibaraki 3058565, Japan. NTT, Adv Technol Corp, Ctr Mat Dev & Analyt Technol, Atsugi, Kanagawa 2430198, Japan. Japan Energy Co Ltd, Toda, Saitama 3358503, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Shimada, H (reprint author), Natl Inst Mat & Chem Res, 1-1 Higashi, Tsukuba, Ibaraki 3058565, Japan. RI Tanuma, Shigeo/H-2681-2011; Shimada, Hiromichi/K-6932-2016 OI Shimada, Hiromichi/0000-0002-0115-7785 NR 21 TC 9 Z9 9 U1 1 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD MAY PY 2000 VL 29 IS 5 BP 336 EP 340 DI 10.1002/(SICI)1096-9918(200005)29:5<336::AID-SIA877>3.3.CO;2-N PG 5 WC Chemistry, Physical SC Chemistry GA 317AQ UT WOS:000087201600007 ER PT J AU Harper, S AF Harper, S TI Thermocline ventilation and pathways of tropical-subtropical water mass exchange SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID CENTRAL EQUATORIAL PACIFIC; NORTH-ATLANTIC OCEAN; TRITIUM MAXIMUM; WORLD OCEAN; MEAN WATER; CLIMATE; CIRCULATION; VARIABILITY; TEMPERATURE; GCM AB The mechanism of thermocline ventilation is investigated using a global, high-resolution ocean GCM, with realistic topography and surface wind forcing. Because 2-dimensional representations of circulation can be misleading, the subsurface flow is examined by visualizing the trajectories of particles which subduct in the mid-latitudes and travel within the ventilated thermocline. Three model runs are performed, each with identical surface forcing but with different initial particle distributions. Results from these runs show that the pathways of water mass exchange between the tropics and the subtropics are functions of the surface wind forcing, background density structure, and basin geometry. In the Pacific, ventilated waters from the northern and southern mid-latitudes reach the tropical thermocline through both the western boundary and the interior of the basin. In the Atlantic Ocean, the equatorial thermocline is ventilated primarily through water mass exchange with the southern hemisphere alone. In the Indian Ocean, the pathways of water mass exchange have patterns similar to those in the Atlantic and Pacific basins, though the lack of a mid-latitude gyre in the northern basin restricts the deep subduction and ventilation to the southern hemisphere. C1 Princeton Univ, Program Atmospher & Ocean Sci, Dept Geosci, Princeton, NJ 08544 USA. RP Harper, S (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, Dept Geosci, Princeton, NJ 08544 USA. NR 28 TC 40 Z9 41 U1 2 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD MAY PY 2000 VL 52 IS 3 BP 330 EP 345 DI 10.1034/j.1600-0870.2000.d01-7.x PG 16 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 304XK UT WOS:000086509200007 ER PT J AU Jones-Lepp, T Gerlach, CL Cooter, EJ AF Jones-Lepp, T Gerlach, CL Cooter, EJ TI The power of analytical methods for measuring suspected endocrine disrupting compounds: a pilot field study SO TRAC-TRENDS IN ANALYTICAL CHEMISTRY LA English DT Article DE endocrine disrupting compounds; field screening methods; hormonally active agents ID WILDLIFE AB International awareness of the potential hazards posed by endocrine disrupting compounds has led to several programs to optimize the selection, sampling, and analysis of a wide variety of media. The interpretation of analytical results and any subsequent regulatory changes can only be as reliable as the weakest link in the protocol. The U.S. Environmental Protection Agency (EPA) is currently engaged in a multi-disciplinary project to ensure that the analytical methods used are sufficient for the task. The Neuse River in North Carolina was chosen for a pilot study because of its geographic scale, contaminant spectrum, and potential for human and ecological exposure. Methods are being developed or modified for the study. Samples taken in 1998 are being analyzed to determine contaminant levels, compare analytical method results, build a working database, and observe any correlation among analyte groups. Samples include water, sediment, soil, fish, clams, mammals, and certain agricultural crops. This ambitious research project is a concerted effort of the EPA Office of Research and Development and the United States Geological Survey. It combines technological innovation, biological interpretation, and data analysis to strengthen the analytical protocol used to measure trace contaminants in various environmental matrices. (C) 2000 Elsevier Science B.V. All rights reserved. C1 US EPA, Las Vegas, NV 89193 USA. Lockheed Martin Corp, Las Vegas, NV 89119 USA. NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27711 USA. RP Jones-Lepp, T (reprint author), US EPA, POB 93478, Las Vegas, NV 89193 USA. NR 15 TC 20 Z9 20 U1 0 U2 9 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0165-9936 J9 TRAC-TREND ANAL CHEM JI Trac-Trends Anal. Chem. PD MAY PY 2000 VL 19 IS 5 BP 286 EP 291 DI 10.1016/S0165-9936(99)00218-6 PG 6 WC Chemistry, Analytical SC Chemistry GA 309CR UT WOS:000086750500006 ER PT J AU Beckman, BR Larsen, DA Sharpe, C Lee-Pawlak, B Schreck, CB Dickhoff, WW AF Beckman, BR Larsen, DA Sharpe, C Lee-Pawlak, B Schreck, CB Dickhoff, WW TI Physiological status of naturally reared juvenile spring chinook salmon in the Yakima River: Seasonal dynamics and changes associated with smolting SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID GROWTH-FACTOR-I; TROUT ONCORHYNCHUS-MYKISS; UPPER FRASER-RIVER; ATLANTIC SALMON; COHO SALMON; RAINBOW-TROUT; BRITISH-COLUMBIA; LIVER-GLYCOGEN; BROWN TROUT; HYPOOSMOREGULATORY ABILITY AB Two year-classes of juvenile spring chinook salmon Oncorhynchus tshawytscha from the Yakima River, Washington, were sampled from July (3-4 months postemergence) through May (yearling smolt out-migration). Physiological characters measured included liver glycogen, body lipid, gill Na+-K+ ATPase, plasma thyroxine (T-4), and plasma insulin-like growth factor-I (IGF-I). Distinct physiological changes were found that corresponded to season. Summer and fall were characterized by relatively high body lipid and condition factor. Winter was characterized by decreases in body lipid, condition factor, and plasma hormones. An increase in condition factor and body lipid was found in February and March. Finally, April and May were characterized by dramatic changes characteristic of smelting, including increased gill Na+-K+ ATPase activity, plasma T-4, and IGF-I and decreased condition factor, body lipid, and liver glycogen. These results create a physiological template for juvenile spring chinook salmon in the drainage that provides a baseline for comparison with other years, populations, and life history types. In addition, this baseline provides a standard for controlled laboratory experiments and a target for fish culturists who rear juvenile spring chinook salmon for release from conservation hatcheries. The implications of these results for juvenile chinook salmon ecology and life history are discussed. C1 Natl Marine Fisheries Serv, Integrat Fish Biol Program, NW Fisheries Sci Ctr, Natori, Miyagi 98112, Japan. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. Oregon State Univ, Oregon Cooperat Fishery Res Unit, Biol Resources Div, US Geol Survey, Corvallis, OR 97331 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. RP Beckman, BR (reprint author), Natl Marine Fisheries Serv, Integrat Fish Biol Program, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Natori, Miyagi 98112, Japan. NR 81 TC 63 Z9 64 U1 1 U2 15 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD MAY PY 2000 VL 129 IS 3 BP 727 EP 753 DI 10.1577/1548-8659(2000)129<0727:PSONRJ>2.3.CO;2 PG 27 WC Fisheries SC Fisheries GA 349ZX UT WOS:000089076500008 ER PT J AU Wilson, KB Baldocchi, DD Hanson, PJ AF Wilson, KB Baldocchi, DD Hanson, PJ TI Spatial and seasonal variability of photosynthetic parameters and their relationship to leaf nitrogen in a deciduous forest SO TREE PHYSIOLOGY LA English DT Article DE A/C-i curve; drought; gas exchange; leaf age; maple; oak ID PETRAEA MATT LIEBL; NORTHERN RED OAK; GAS-EXCHANGE; USE EFFICIENCY; STOMATAL CONDUCTANCE; CO2 ASSIMILATION; CARBON GAIN; NET PHOTOSYNTHESIS; FIELD CONDITIONS; PHOTOSYSTEM-II AB We used gas exchange techniques to estimate maximum rate of carboxylation (V-cmax), a measure of photosynthetic capacity, in the understory and upper crown of a closed deciduous forest over two seasons. There was extensive variability in photosynthetic capacity as a result of vertical canopy position, species type, leaf age and drought. Photosynthetic capacity was greater in oaks than in maples and greater in the overstory than in the understory. Parameter V-cmax was maximal early in the season but declined slowly throughout most of the summer, and then more rapidly during senescence. There was also an apparent decline during drought in some trees. Variability in V-cmax as a result of species or vertical canopy gradients was described well by changes in leaf nitrogen per unit area (N-a). However, temporal changes in V-cmax were often poorly correlated with leaf nitrogen, especially in spring and summer and during drought. This poor correlation may be the result of a seasonally dependent fractional allocation of leaf nitrogen to Rubisco; however, we could not discount Rubisco inactivation, patchy stomatal closure or changes in mesophyll resistance. Consequently, when a single annual regression equation of V-cmax versus N-a was used for this site, there were substantial errors in the temporal patterns in V-cmax that will inevitably result in modeling errors. 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; Baldocchi, Dennis/A-1625-2009 OI Hanson, Paul J./0000-0001-7293-3561; Baldocchi, Dennis/0000-0003-3496-4919 NR 58 TC 215 Z9 224 U1 8 U2 43 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 MAY PY 2000 VL 20 IS 9 BP 565 EP 578 PG 14 WC Forestry SC Forestry GA 315JV UT WOS:000087111300001 ER PT J AU Kedzierski, P Sokalski, WA Krauss, M AF Kedzierski, P Sokalski, WA Krauss, M TI Nonempirical analysis of nature of catalytic effects in ribonuclease A active site SO JOURNAL OF COMPUTATIONAL CHEMISTRY LA English DT Article DE ribonuclease A; catalytic activity; electrostatic effects; intermolecular interactions; active site ID MOLECULAR CHARGE-DISTRIBUTION; BASIS SET DEPENDENCE; INTERACTION ENERGY; HYDROGEN BOND; HYDROLYSIS; PHOSPHATE; TRANSPHOSPHORYLATION; DECOMPOSITION; MECHANISM; MODELS AB The physical nature of the catalytic activity exerted by various ribonuclease A active site constituents is analyzed in terms of the differential transition state stabilization approach in which activation barrier changes induced by the molecular environment are expressed by additive components defined in the theory of intermolecular interactions. Electrostatic multipole contributions seem to approximate total catalytic activity well for residues separated by contacts longer than 2.7 Angstrom whereas at shorter distances the remaining exchange and delocalization terms are not negligible. Depending on the reaction step, the same residue may exhibit catalytic or inhibitory activity. (C) 2000 John Wiley & Sons, Inc. C1 Wroclaw Univ Technol, Inst Phys & Theoret Chem, PL-50370 Wroclaw, Poland. Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Sokalski, WA (reprint author), Wroclaw Univ Technol, Inst Phys & Theoret Chem, Wyb Wyspianskiego 27, PL-50370 Wroclaw, Poland. RI Sokalski, Waclaw/I-6151-2012 NR 40 TC 6 Z9 6 U1 0 U2 6 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0192-8651 J9 J COMPUT CHEM JI J. Comput. Chem. PD APR 30 PY 2000 VL 21 IS 6 BP 432 EP 445 PG 14 WC Chemistry, Multidisciplinary SC Chemistry GA 296WB UT WOS:000086048800003 ER PT J AU Jensen, RP Luecke, WE Padture, NP Wiederhorn, SM AF Jensen, RP Luecke, WE Padture, NP Wiederhorn, SM TI High-temperature properties of liquid-phase-sintered alpha-SiC SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE silicon carbide; dynamic fatigue; constant stress-rate testing; subcritical crack growth; oxidation ID SLOW CRACK-GROWTH; SILICON-CARBIDE; MECHANICAL-PROPERTIES; OXIDATION-KINETICS; ADDITIVES; FRACTURE AB We have characterized the high-temperature subcritical crack growth and oxidation resistance of a liquid-phase-sintered (LPS) SIC with 20% volume fraction yttrium aluminum garnet (YAG) second phase. Constant stress-rate testing in air in the temperature range 1100-1300 degrees C yielded a crack growth exponent, n = 38.9 +/- 9.9 and an activation energy, Q(scg) = (380 +/- 237) kJ mol(-1). Oxidation followed parabolic kinetics in the temperature range 1100-1300 degrees C with an activation energy, Q(ox) = (246 +/- 33) kJ mol(-1). At 1350 degrees C reaction between the growing oxide layer and the YAG second phase produced a low-melting eutectic, resulting in accelerated oxidation. Below 1100 degrees C, oxidation rates were also anomalously high for reasons we do not understand. In the intermediate temperature range, both the oxidation and subcritical crack growth resistance compare favorably with other silicon carbides. Published by Elsevier Science S.A. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. Univ Connecticut, Inst Mat Sci, Dept Met & Mat Engn, Storrs, CT 06269 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Luecke, WE (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RI Padture, Nitin/A-9746-2009; OI Padture, Nitin/0000-0001-6622-8559; Luecke, William/0000-0003-0587-4500 NR 32 TC 28 Z9 35 U1 0 U2 6 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 APR 30 PY 2000 VL 282 IS 1-2 BP 109 EP 114 DI 10.1016/S0921-5093(99)00769-8 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 295LB UT WOS:000085966600015 ER PT J AU Jones, DJ Diddams, SA Ranka, JK Stentz, A Windeler, RS Hall, JL Cundiff, ST AF Jones, DJ Diddams, SA Ranka, JK Stentz, A Windeler, RS Hall, JL Cundiff, ST TI Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis SO SCIENCE LA English DT Article ID PULSES; GENERATION AB We stabilized the carrier-envelope phase of the pulses emitted by a femtosecond mode-locked Laser by using the powerful tools of frequency-domain laser stabilization. We confirmed control of the pulse-to-pulse carrier-envelope phase using temporal cross correlation. This phase stabilization Locks the absolute frequencies emitted by the Laser, which we used to perform absolute optical frequency measurements that were directly referenced to a stable microwave clock. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Bell Labs, Lucent Technol, Holmdel, NJ 07733 USA. RP Cundiff, ST (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Cundiff, Steven/B-4974-2009; Diddams, Scott/L-2819-2013; Jones, David/F-5859-2017 OI Cundiff, Steven/0000-0002-7119-5197; NR 27 TC 1527 Z9 1562 U1 39 U2 237 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 APR 28 PY 2000 VL 288 IS 5466 BP 635 EP 639 DI 10.1126/science.288.5466.635 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 308RR UT WOS:000086727100035 ER PT J AU Yi, C Davis, KJ Bakwin, PS Berger, BW Marr, LC AF Yi, C Davis, KJ Bakwin, PS Berger, BW Marr, LC TI Influence of advection on measurements of the net ecosystem-atmosphere exchange of CO2 from a very tall tower SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CARBON-DIOXIDE UPTAKE; WATER-VAPOR EXCHANGE; SURFACE-AIR EXCHANGE; DOUGLAS-FIR STAND; MICROMETEOROLOGICAL OBSERVATIONS; CLIMATE-CHANGE; BOREAL FOREST; RAIN-FOREST; FLUXES; VEGETATION AB In most studies of the net ecosystem-atmosphere exchange of CO2 (NEE) using tower-based eddy covariance (EC) systems it has been assumed that advection is negligible. In this study we use a scalar conservation budget method to estimate the contribution of advection to NEE measurements from a very tall tower in northern Wisconsin. We examine data for June-August 1997. Measured NEE0, calculated as the sum of the EC flux plus the rate of change of storage below the EC measurement level, is expected to be constant with measurement height, and we take the differences between levels as a measure of advection. We find that the average difference in total advection Delta F-Cadtot between 30 and 122 m is as large as 6 mu mol m(-2) s(-1) during the morning transition from stable to convective conditions and the average difference Delta F-Cadtot between 122 and 396 m is as large as 4 mu mol m(-2) s(-1) during daytime. For the month of July, advection between 30 and 122 m is 27% of the diurnally integrated NEE0 at 122 m, and advection between 122 and 396 m accounts for 5% of the NEE0 observed at 396 m. The observed differences of advection often have significant correlation with the vertical integral of wind speed within the same layer. This indicates that the horizontal advection contribution to NEE could be significant. Direct observations of the vertical gradient in CO2 show that Delta F-Cadtot cannot be explained by vertical advection alone. It is hypothesized that differing flux footprints and pooling of CO2 in the heterogeneous landscape causes the advection contribution. The magnitudes of the total advection component F-Cadtot of NEE at the 30 m level are roughly estimated by a linear extrapolation. A peak in F-Cadtot at 30 m of similar to 3 mu mol m(-2) s(-1) during the morning transition is predicted for all three months. The July integrated F-Cadtot is estimated to be 10% of the diurnally integrated NEE0 at 30m. C1 Univ Minnesota, Dept Soil Water & Climate, St Paul, MN 55108 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA. RP Yi, C (reprint author), Univ Minnesota, Dept Soil Water & Climate, 1991 Upper Buford Circle, St Paul, MN 55108 USA. EM cxyi@soils.umn.edu; davis@soils.umn.edu; pbakwin@cmdl.noaa.gov; bberger@gis.umn.edu; lmarr@zephyr.ce.berkeley.edu RI Marr, Linsey/C-9698-2010; Lucas, Elizabeth/E-2733-2010; Yi, Chuixiang/A-1388-2013 OI Marr, Linsey/0000-0003-3628-6891; NR 43 TC 80 Z9 81 U1 0 U2 15 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 APR 27 PY 2000 VL 105 IS D8 BP 9991 EP 9999 DI 10.1029/2000JD900080 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 307ND UT WOS:000086658600017 ER PT J AU Dye, JE Ridey, BA Skamarock, W Barth, M Venticinque, M Defer, E Blanchet, P Thery, C Laroche, P Baumann, K Hubler, G Parrish, DD Ryerson, T Trainer, M Frost, G Holloway, JS Matejka, T Bartels, D Fehsenfeld, FC Tuck, A Rutledge, SA Lang, T Stith, J Zerr, R AF Dye, JE Ridey, BA Skamarock, W Barth, M Venticinque, M Defer, E Blanchet, P Thery, C Laroche, P Baumann, K Hubler, G Parrish, DD Ryerson, T Trainer, M Frost, G Holloway, JS Matejka, T Bartels, D Fehsenfeld, FC Tuck, A Rutledge, SA Lang, T Stith, J Zerr, R TI An overview of the Stratospheric-Tropospheric Experiment: Radiation, Aerosols, and Ozone (STERAO)-Deep Convection experiment with results for the July 10, 1996 storm SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LIGHTNING FLASHES; THUNDERSTORMS; NOX; TRANSPORT; NITROGEN; DOPPLER; DISCHARGES; FLORIDA AB The Stratospheric-Tropospheric Experiment: Radiation, Aerosols and Ozone (STERAO)-Deep Convection Field Project with closely coordinated chemical, dynamical, electrical, and microphysical observations was conducted in northeastern Colorado during June and July of 1996 to investigate the production of NOX by lightning, the transport and redistribution of chemical species in the troposphere by thunderstorms, and the temporal evolution of intracloud and cloud-to-ground lightning for evolving storms on the Colorado high plains. Major observations were airborne chemical measurements in the boundary layer, middle and upper troposphere, and thunderstorm anvils; airborne and ground-based Doppler radar measurements; measurement of both intracloud (IC) and cloud-to-ground (CG) lightning flash rates and locations; and multiparameter radar and in situ observations of microphysical structure. Cloud and mesoscale models are being used to synthesize and extend the observations. Herein we present an overview of the project and selected results for an isolated, severe storm that occurred on July 10, Time histories of reflectivity structure, IC and CG lightning flash rates, and chemical measurements in the boundary layer and in the anvil are presented showing large spatial and temporal variations. The observations for one period of time suggest that limited mixing of environmental air into the updraft core occurred during transport from cloud base to the anvil adjacent to the storm core. We deduce that the most likely contribution of lightning to the total NOX observed in the anvil is 60-90% with a minimum of 45%, For the July 10 storm the NOX produced by lightning was almost exclusively from IC flashes with a ratio of IC to total flashes >0.95 throughout most of the storm's lifetime. It is argued that in this storm and probably others, IC flashes can be major contributors to NOX production. Superposition of VHF lightning source locations on Doppler retrieved air motion fields for one 5 min time period shows that lightning activity occurred primarily in moderate updrafts and weak downdrafts with little excursion into the main downdraft, This may have important implications for the vertical redistribution of NOX resulting from lightning production, if found to be true at other times and in other storms. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Off Natl Etud & Rech Aerosp, Chatillon, France. NOAA, Natl Severe Storms Lab, Boulder, CO 80307 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. RP Dye, JE (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM dye@ucar.edu RI Hubler, Gerhard/E-9780-2010; Parrish, David/E-8957-2010; Tuck, Adrian/F-6024-2011; Holloway, John/F-9911-2012; Trainer, Michael/H-5168-2013; Ryerson, Tom/C-9611-2009; Frost, Gregory/I-1958-2013; Fehsenfeld, Frederick/I-4876-2013; OI Parrish, David/0000-0001-6312-2724; Tuck, Adrian/0000-0002-2074-0538; Holloway, John/0000-0002-4585-9594; Lang, Timothy/0000-0003-1576-572X NR 46 TC 76 Z9 77 U1 6 U2 16 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 APR 27 PY 2000 VL 105 IS D8 BP 10023 EP 10045 DI 10.1029/1999JD901116 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 307ND UT WOS:000086658600019 ER PT J AU Laursen, SL Delia, AE Mitchell, K AF Laursen, SL Delia, AE Mitchell, K TI Reaction of NH (X (3)Sigma(-)) with NO in xenon matrix: Infrared detection of the HNNO intermediate SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID HIGH-TEMPERATURE PHOTOCHEMISTRY; RARE-GAS; VIBRATIONAL FREQUENCIES; ELEMENTARY REACTIONS; NH+NO REACTION; SOLID XENON; PRODUCT; PHOTODISSOCIATION; MOLECULES; KINETICS AB The reaction of ground-state NH with NO has been investigated in solid xenon matrix. NH radicals are formed in good yield in Xe matrix after UV photolysis of HN3 and are reacted with NO in the matrix by annealing the solid to 40 K. A photolabile product is formed and identified as trans-HNNO by infrared spectroscopy, including isotope labeling and comparison with published frequencies from quantum chemical calculations. A minor product with similar formation and photodestruction behavior is assigned to the cis-HNNO isomer. Cis-trans interconversion was also observed. The reaction to form HNNO is essentially activationless. Upon photolysis at wavelengths up to 600 nm, HNNO is destroyed and converted to N2O. This is the first detection of this intermediate, which plays a role in ammonia combustion and NOx removal schemes. C1 Kalamazoo Coll, Dept Chem, Kalamazoo, MI 49006 USA. RP Laursen, SL (reprint author), NOAA, Aeron Lab, R-AL2,325 Broadway, Boulder, CO 80303 USA. OI LAURSEN, SANDRA/0000-0002-4327-9887 NR 63 TC 12 Z9 12 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 APR 27 PY 2000 VL 104 IS 16 BP 3681 EP 3692 DI 10.1021/jp993854i PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 329GZ UT WOS:000087900400030 ER PT J AU Irikura, KK Johnson, RD Hudgens, JW AF Irikura, KK Johnson, RD Hudgens, JW TI Electronic structure of BCl determined by ab initio calculations and resonance-enhanced multiphoton ionization spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; BASIS-SET CONVERGENCE; GAUSSIAN-BASIS SETS; BORON; SPECTRUM; ALUMINUM; DISSOCIATION; DISCHARGES; EXCITATION; ENERGIES AB The mass-resolved, one-color, 2 + 1 resonance-enhanced multiphoton ionization spectrum of transient boron monochloride (BCl) between 348 and 369 nm is reported. Vibrational and rotational bands of the (BCl)-B-10-Cl-35, (BCl)-B-11-Cl-35, (BCl)-B-10-Cl-37, and (BCl)-B-11-Cl-37 isotopomers and two previously unreported electronic states are assigned. Rotational analysis identifies the F (1)Sigma(+) (3s sigma) state (nu(00) = 55994 +/- 10 cm(-1) for (BCl)-B-11-Cl-35). EE-EOM-CCSD ab initio calculations for BF and BCl support the F state assignment and suggest a tentative assignment of b (3)Sigma(+) (3p sigma) (nu(00) = 56864 +/- 10 cm(-1) for (BCl)-B-11-Cl-35). Uncertainties indicate the confidence of two standard deviations. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Irikura, KK (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 48 TC 16 Z9 16 U1 0 U2 2 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 APR 27 PY 2000 VL 104 IS 16 BP 3800 EP 3805 DI 10.1021/jp994011u PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 329GZ UT WOS:000087900400045 ER PT J AU Alpert, B Greengard, L Hagstrom, T AF Alpert, B Greengard, L Hagstrom, T TI Rapid evaluation of nonreflecting boundary kernels or time-domain wave propagation SO SIAM JOURNAL ON NUMERICAL ANALYSIS LA English DT Article DE Bessel function; approximation; high-order convergence; wave equation; Maxwell's equations; nonreflecting boundary condition; radiation boundary condition; absorbing boundary condition ID APPROXIMATION AB We present a systematic approach to the computation of exact nonreflecting boundary conditions for the wave equation. In both two and three dimensions, the critical step in our analysis involves convolution with the inverse Laplace transform of the logarithmic derivative of a Hankel function. The main technical result in this paper is that the logarithmic derivative of the Hankel function H-nu((1))(z) of real order nu can be approximated in the upper half z-plane with relative error epsilon by a rational function of degree d similar to O(log\nu\ log 1/epsilon + log(2) \nu\ + \nu\(-1) log(2) 1/epsilon) as \nu\ --> infinity, epsilon --> 0, with slightly more complicated bounds for nu = 0. If N is the number of points used in the discretization of a cylindrical (circular) boundary in two dimensions, then, assuming that epsilon < 1/N, O(N log N log 1/epsilon) work is required at each time step. This is comparable to the work required for the Fourier transform on the boundary. In three dimensions, the cost is proportional to N-2 log(2) N + N-2 log N log 1/epsilon for a spherical boundary with N-2 points, the first term coming from the calculation of a spherical harmonic transform at each time step. In short, nonreflecting boundary conditions can be imposed to any desired accuracy, at a cost dominated by the interior grid work, which scales like N-2 in two dimensions and N-3 in three dimensions. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. NYU, Courant Inst Math Sci, New York, NY 10012 USA. Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. RP Alpert, B (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM alpert@boulder.nist.gov; greengar@cims.nyu.edu; hagstrom@math.unm.edu NR 30 TC 105 Z9 110 U1 1 U2 4 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1429 EI 1095-7170 J9 SIAM J NUMER ANAL JI SIAM J. Numer. Anal. PD APR 27 PY 2000 VL 37 IS 4 BP 1138 EP 1164 DI 10.1137/S0036142998336916 PG 27 WC Mathematics, Applied SC Mathematics GA 311DD UT WOS:000086868800005 ER PT J AU Phelan, BA Goldberg, R Bejda, AJ Pereira, J Hagan, S Clark, P Studholme, AL Calabrese, A Able, KW AF Phelan, BA Goldberg, R Bejda, AJ Pereira, J Hagan, S Clark, P Studholme, AL Calabrese, A Able, KW TI Estuarine and habitat-related differences in growth rates of young-of-the-year winter flounder (Pseudopleuronectes americanus) and tautog (Tautoga onitis) in three northeastern US estuaries SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE growth; habitat quality; estuarine quality; juvenile fish; winter flounder; tautog; caging ID JUVENILE SOUTHERN FLOUNDER; EARLY-LIFE-HISTORY; DISSOLVED-OXYGEN; WAQUOIT BAY; NORTH-CAROLINA; NEW-JERSEY; PARALICHTHYS-LETHOSTIGMA; EUTROPHIC ESTUARY; COASTAL WATERS; ULVA-LACTUCA AB Instantaneous growth rates of young-of-the-year winter flounder Pseudopleuronectes americanus (Walbaum) (12.0-60.4 mm standard length, SL) and tautog Tautoga onitis (Linnaeus) (21.4-73.8 mm total length, TL) from three estuarine systems in New Jersey (Great Bay-Little Egg Harbor and Navesink River) and Connecticut (Hammonasset River) were used in an attempt to assess the relative quality of selected nominal habitats. A series of short-term field caging experiments were conducted during 1994 and 1995 in: macroalgae (primarily, Ulva lactuca), eelgrass (Zostera marina), unvegetated areas adjacent to macroalgae and eelgrass and tidal creeks in Spartina dominated marsh. Growth rates varied with habitat, estuary and year. Comparisons across nominal habitats within and among estuaries did not show any one habitat with consistently higher growth, and growth was relatively independent of whether a habitat was vegetated or adjacent to vegetation. The growth rates of winter flounder and tautog from the Hammonasset River were not different among habitats in either year of the study. In the Great Bay-Little Egg Harbor, both winter flounder and tautog had higher growth rates in macroalgae with growth in eelgrass varying significantly between years. Conversely, in the Navesink River both species had higher growth rates in eelgrass. Environmental changes associated with temperature and dissolved oxygen appeared to influence growth rates. Winter flounder growth rate and survival was depressed in tidal marsh creeks in the three estuaries and in vegetated macroalgae habitats in the Navesink River where dissolved oxygen levels were often very low (<2 mg l(-1)) for extended periods. In summary, the growth rates of the young-of-the-year of these two species varied temporally and were dependent on the interaction or both the specific estuary and habitat in which the experiments took place. Further, habitat quality, as defined by relative growth rare, was difficult to evaluate because it can be variable and nominal habitat designations are often not sufficient to define the boundaries of a species habitat requirements. Published by Elsevier Science B.V. C1 James J Howard Marine Sci Lab, Natl Marine Fisheries Serv, Highlands, NJ 07732 USA. Natl Marine Fisheries Serv, Milford Lab, Milford, CT 06460 USA. Rutgers State Univ, Marine Field Stn, Inst Marine & Coastal Sci, Tuckerton, NJ 08087 USA. RP Phelan, BA (reprint author), James J Howard Marine Sci Lab, Natl Marine Fisheries Serv, 74 Magruder Rd, Highlands, NJ 07732 USA. EM beth.phelan@noaa.gov NR 58 TC 103 Z9 104 U1 1 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD APR 26 PY 2000 VL 247 IS 1 BP 1 EP 28 DI 10.1016/S0022-0981(99)00184-7 PG 28 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 300JK UT WOS:000086249700001 ER PT J AU Simon, SL McKenna, GB Sindt, O AF Simon, SL McKenna, GB Sindt, O TI Modeling the evolution of the dynamic mechanical properties of a commercial epoxy during cure after gelation SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE cure; epoxy; thermoset; viscoelastic properties; shear modulus ID GLASS-TRANSITION TEMPERATURE; REACTION-KINETICS; CURING REACTION; EPOXIDES; NETWORK; AMINES; TG; TRANSFORMATION; POLYMERIZATION; CONVERSION AB The cure kinetics for a commercial epoxy have been established and the influence of the degree of cure on the glass transition determined. Time-temperature and time-conversion superposition principles have been built into a model that successfully predicts the development of the viscoelastic properties of the epoxy during isothermal cure from gelation to after vitrification. (C) 2000 John Wiley & Sons, Inc.* C1 Texas Tech Univ, Dept Chem Engn, Lubbock, TX 79409 USA. Univ Pittsburgh, Pittsburgh, PA 15260 USA. Natl Inst Stand & Technol, Boulder, CO USA. RP Simon, SL (reprint author), Texas Tech Univ, Dept Chem Engn, Lubbock, TX 79409 USA. RI Simon, Sindee/M-9372-2013; McKenna, Gregory/O-1134-2013 OI Simon, Sindee/0000-0001-7498-2826; McKenna, Gregory/0000-0002-5676-9930 NR 29 TC 99 Z9 99 U1 4 U2 27 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD APR 25 PY 2000 VL 76 IS 4 BP 495 EP 508 DI 10.1002/(SICI)1097-4628(20000425)76:4<495::AID-APP7>3.0.CO;2-B PG 14 WC Polymer Science SC Polymer Science GA 288UV UT WOS:000085583600007 ER PT J AU Clancy, RT Sandor, BJ Wolff, MJ Christensen, PR Smith, MD Pearl, JC Conrath, BJ Wilson, RJ AF Clancy, RT Sandor, BJ Wolff, MJ Christensen, PR Smith, MD Pearl, JC Conrath, BJ Wilson, RJ TI An intercomparison of ground-based millimeter, MGS TES, and Viking atmospheric temperature measurements: Seasonal and interannual variability of temperatures and dust loading in the global Mars atmosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARTIAN ATMOSPHERE; MODEL; MARINER-9; PHOBOS; STORMS; MICROWAVE; SURVEYOR; APHELION; BEHAVIOR; CLIMATE AB During the period October 1997 to September 1999 we obtained and analyzed over 100 millimeter-wave observations of Mars atmospheric CO line absorption for atmospheric temperature profiles. These measurements extend through one full Mars year (solar longitudes L-S of 190 degrees in 1997 to 180 degrees in 1999) and coincide with atmospheric temperature profile and dust column measurements from the Thermal Emission Spectrometer (TES) experiment on board the Mars Global Surveyor (MGS) spacecraft. A comparison of Mars atmospheric temperatures retrieved by these distinct methods provides the first opportunity to place the long-term (1982-1999) millimeter retrievals of Mars atmospheric temperatures within the context of contemporaneous, spatially mapped spacecraft observations. Profile comparisons of 0-30 km altitude atmospheric temperatures retrieved with the two techiques agree typically to within the 5 K calibration accuracy of the millimeter observations. At the 0.5 mbar pressure level (similar to 25 km altitude) the 30 degrees N/30 degrees S average for TES infrared temperatures and the disk-averaged millimeter temperatures are also well correlated in their seasonal and dust-storm-related variations over the 1997-1999 period. This period includes the Noachis Terra regional dust storm, which led to very abrupt heating (similar to 15 K at 0.5 mbar) of the global Mars atmosphere at L-S = 224 degrees in 1997 [Christensen et al., 1998; Conrath et al., this issue; Smith et al., this issue]. Much colder (10-20 It) global atmospheric temperatures were observed during the 1997 versus 1977 perihelion periods (L-S = 200 degrees-330 degrees), consistent with the much (2 to 8 times) lower global dust loading of the atmosphere during the 1997 perihelion dust storm season versus the Viking period of the 1977a,b storms. The 1998-1999 Mars atmosphere revealed by both the millimeter and TES observations is also 10-15 K colder than presented by the Viking climatology during the aphelion season (L-S = 0 degrees-180 degrees, northern spring/summer) of Mars. We reassess the observational basis of the Viking dusty-warm climatology for this season to conclude that the global aphelion atmosphere of Mars is colder, less dusty, and cloudier than indicated by the established Viking climatology even for the Viking period. We also conclude that Mars atmospheric temperatures exhibit their most significant interannual variations during the perihelion dust storm season (10-20 K for L-S = 200 degrees-340 degrees) and during the post-aphelion northern summer season (5-10 K for L-S = 100 degrees-200 degrees). C1 Space Sci Inst, Boulder, CO 80303 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Clancy, RT (reprint author), Space Sci Inst, 3100 Marine St,Suite A353, Boulder, CO 80303 USA. RI Smith, Michael/C-8875-2012 NR 58 TC 213 Z9 215 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD APR 25 PY 2000 VL 105 IS E4 BP 9553 EP 9571 DI 10.1029/1999JE001089 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 306HG UT WOS:000086590800011 ER PT J AU Caliebe, WA Soininen, JA Shirley, EL Kao, CC Hamalainen, K AF Caliebe, WA Soininen, JA Shirley, EL Kao, CC Hamalainen, K TI Dynamic structure factor of diamond and LiF measured using inelastic X-ray scattering SO PHYSICAL REVIEW LETTERS LA English DT Article ID AB-INITIO CALCULATION; PLASMON DISPERSION; BAND-STRUCTURE; ELECTRONS; METAL; RESOLUTION; SEMICONDUCTORS; SPECTROMETER; INSULATORS; AL AB The dynamic structure factors S((q) over right arrow, omega) of diamond and LiF have been measured using inelastic x-ray scattering. The experimental data are compared to results of ab initio calculations, which take into account the interaction of the excited electron with the remaining hole. In diamond, the vicinity of the indirect band gap and its momentum dependence are studied. In LiF, a larger energy range, which covers the fundamental exciton, the plasmon, and several interband transitions, is investigated. Calculations and measurements agree quite well and emphasize the need to properly include the interaction of the excited electron in the conduction band with the hole in the valence band. C1 Forschungszentrum, Inst Festkorperforsch, D-52425 Julich, Germany. Natl Inst Stand & Technol, Opt Technol Div, Phys Lab, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. RP Forschungszentrum, Inst Festkorperforsch, D-52425 Julich, Germany. RI Hamalainen, Keijo/A-3986-2010 OI Hamalainen, Keijo/0000-0002-9234-9810 NR 30 TC 43 Z9 43 U1 1 U2 8 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 APR 24 PY 2000 VL 84 IS 17 BP 3907 EP 3910 DI 10.1103/PhysRevLett.84.3907 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900044 ER PT J AU Fitzsimmons, MR Yashar, P Leighton, C Schuller, IK Nogues, J Majkrzak, CF Dura, JA AF Fitzsimmons, MR Yashar, P Leighton, C Schuller, IK Nogues, J Majkrzak, CF Dura, JA TI Asymmetric magnetization reversal in exchange-biased hysteresis loops SO PHYSICAL REVIEW LETTERS LA English DT Article ID FEF2-FE BILAYERS; THIN-FILMS; INTERFACES; ANISOTROPY; SYSTEMS AB Polarized neutron reflectometry is used to probe the in-plane projection of the net-magnetization Vector (M) over bar of polycrystalline Fe films exchange coupled to twinned (110) MnF2 or FeF2 antiferromagnetic (AF) layers. The magnetization reversal mechanism depends upon the orientation of the cooling field with respect to the twinned microstructure of the AF, and whether the applied field is increased to (or decreased from) a positive saturating field; i.e., the magnetization reversal is asymmetric. The reversal of the sample magnetization from one saturated state to the other occurs via either domain wall motion or magnetization rotation on opposite sides of the same hysteresis loop. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Univ Autonoma Barcelona, Dept Fis, Bellaterra 08193, Spain. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fitzsimmons, MR (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. RI Dura, Joseph/B-8452-2008; Nogues, Josep/D-7791-2012; Lujan Center, LANL/G-4896-2012 OI Dura, Joseph/0000-0001-6877-959X; Nogues, Josep/0000-0003-4616-1371; NR 25 TC 273 Z9 274 U1 7 U2 63 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 APR 24 PY 2000 VL 84 IS 17 BP 3986 EP 3989 DI 10.1103/PhysRevLett.84.3986 PG 4 WC Physics, Multidisciplinary SC Physics GA 307CM UT WOS:000086635900064 ER PT J AU Montzka, SA Spivakovsky, CM Butler, JH Elkins, JW Lock, LT Mondeel, DJ AF Montzka, SA Spivakovsky, CM Butler, JH Elkins, JW Lock, LT Mondeel, DJ TI New observational constraints for atmospheric hydroxyl on global and hemispheric scales SO SCIENCE LA English DT Article ID METHYL CHLOROFORM; TROPOSPHERIC OH; HYDROCARBONS; HALOCARBONS; ABUNDANCE; EMISSIONS; LIFETIME; CH3CCL3; OZONE AB Dramatic declines in emissions of methyl chloroform (1,1,1 -trichloroethane) resulting from the Montreal Protocol provide an unprecedented opportunity to improve our understanding of the oxidizing power of Earth's atmosphere. Atmospheric observations of this industrial gas during the late 1990s yield new insights into the global burden and distribution of the hydroxyl radical. Our results set firm upper limits on the global and Southern Hemispheric lifetimes of methyl chloroform and confirm the predominance of hydroxyl in the tropics. Our analysis suggests a global lifetime for methyl chloroform of 5.2 (+0.2, -0.3) years, a Southern Hemispheric Lifetime of 4.9 (+0.2, -0.3) years, and mean annual concentrations of OH that are 15 +/- 10% higher south of the intertropical convergence zone than those north of this natural mixing boundary between the hemispheres. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Montzka, SA (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. OI Montzka, Stephen/0000-0002-9396-0400 NR 24 TC 85 Z9 86 U1 2 U2 21 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 APR 21 PY 2000 VL 288 IS 5465 BP 500 EP 503 DI 10.1126/science.288.5465.500 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 306YJ UT WOS:000086626000041 ER PT J AU Nelson, BC Rockwell, GF Campfield, T O'Grady, P Hernandez, RM Wise, SA AF Nelson, BC Rockwell, GF Campfield, T O'Grady, P Hernandez, RM Wise, SA TI Capillary electrophoretic determination of oxalate in amniotic fluid SO ANALYTICA CHIMICA ACTA LA English DT Article DE amniotic fluid; biological fluids; blood plasma; capillary electrophoresis; oxalate; total parenteral nutrition solutions ID PERFORMANCE LIQUID-CHROMATOGRAPHY; TOTAL PARENTERAL-NUTRITION; BIRTH-WEIGHT INFANTS; ZONE ELECTROPHORESIS; ORGANIC-ACIDS; ION-CHROMATOGRAPHY; INORGANIC ANIONS; URINARY OXALATE; OXALIC-ACID; PRIMARY HYPEROXALURIA AB A capillary electrophoretic (CE) assay for oxalate has been applied to the quantitative determination of free oxalate in amniotic fluid. Indirect absorbance detection of oxalate is accomplished with a chromate-based background electrolyte modified with ethylenediaminetetraacetic acid (EDTA). Detection interference due to the presence of high levels (approximate to 4 mg/ml) of inorganic chloride is eliminated through a direct sample clean-up procedure based on cation (Ag+-form) resins. Separation interference from amniotic fluid proteins is prevented through the use of a simple aqueous-based dilution procedure. This method for the determination of oxalate in amniotic fluid provides precision of approximate to 5% relative standard deviation (RSD). Within-day precisions for the oxalate response and migration time are better than 3% RSD and 1% RSD, respectively. Between-day precisions for the oxalate response and migration time are better than 6% RSD and 3% RSD, respectively. The analytical recovery of oxalate (1000 ng/ml) spiked into amniotic fluid was better than 96%. The limit of detection (LOD) for the method is approximate to 100 ng/ml oxalate. This method also shows promising results for the determination of oxalate in human blood plasma samples. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. Baystate Med Ctr, Wesson Womens Hosp, Springfield, MA 01199 USA. RP Nelson, BC (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 42 TC 10 Z9 10 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD APR 20 PY 2000 VL 410 IS 1-2 BP 1 EP 10 DI 10.1016/S0003-2670(00)00711-X PG 10 WC Chemistry, Analytical SC Chemistry GA 305EX UT WOS:000086527400001 ER PT J AU Cerrada, ML McKenna, GB AF Cerrada, ML McKenna, GB TI Physical aging of amorphous PEN: Isothermal, isochronal and isostructural results SO MACROMOLECULES LA English DT Article ID STRUCTURAL RELAXATION; ENTHALPY RECOVERY; ELECTRICAL RELAXATION; ISOBARIC VOLUME; POLYMERS; CREEP; GLASS; SUPERPOSITION; TEMPERATURE; BEHAVIOR AB The sub-glass-transition viscoelastic and physical aging responses of an amorphous poly(ethylene naphthalate) (PEN) have been studied using uniaxial tension stress relaxation experiments. It is known that PEN exhibits a strong beta relaxation that overlaps the a relaxation in the experimental time and temperature ranges studied. In prior work, we had shown that both amorphous and semicrystalline PEN exhibit thermorheologically complex behaviors in that neither time-temperature nor time-aging time superposition apply to the materials. Here we compare results from two-step aging experiments in which the material is first annealed at a temperature near the nominal glass transition temperature of 120 degrees C. In the second step, the viscoelastic response of the material is tested at a lower temperature, following classical sequential aging techniques. We find, for samples first annealed at 100 degrees C, that the amorphous PEN shows time-temperature superposition behavior for constant annealing times. The results are interpreted in terms of an isostructural or constant fictive temperature glass. When the responses are compared isothermally for different fictive temperatures, as found previously, thermorheological simplicity breaks down. Possible reasons for this behavior are discussed. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP McKenna, GB (reprint author), Texas Tech Univ, Dept Chem Engn, Lubbock, TX 79409 USA. RI McKenna, Gregory/O-1134-2013; CERRADA, MARIA/E-9810-2016 OI McKenna, Gregory/0000-0002-5676-9930; CERRADA, MARIA/0000-0003-4261-0627 NR 42 TC 45 Z9 45 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 18 PY 2000 VL 33 IS 8 BP 3065 EP 3076 DI 10.1021/ma990400a PG 12 WC Polymer Science SC Polymer Science GA 307WG UT WOS:000086676700043 ER PT J AU Lee, SH Broholm, C Kim, TH Ratcliff, W Cheong, SW AF Lee, SH Broholm, C Kim, TH Ratcliff, W Cheong, SW TI Local spin resonance and spin-Peierls-like phase transition in a geometrically frustrated antiferromagnet SO PHYSICAL REVIEW LETTERS LA English DT Article ID PYROCHLORE ANTIFERROMAGNET; KAGOME ANTIFERROMAGNET; ORDER; DISORDER; LIQUID; CR3+ AB Inelastic magnetic neutron scattering reveals a localized spin resonance at 4.5 meV in the ordered phase of the geometrically frustrated cubic antiferromagnet ZnCr2O4. The resonance develops abruptly from quantum critical fluctuations upon cooling through a first order transition to a co-planar antiferromagnet at T-c = 12.5(5) K. We argue that this transition is a three dimensional analog of the spin-Peierls transition. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Lee, SH (reprint author), Rutgers State Univ, Dept Phys & Astron, POB 849, Piscataway, NJ 08854 USA. RI Broholm, Collin/E-8228-2011 OI Broholm, Collin/0000-0002-1569-9892 NR 27 TC 263 Z9 266 U1 4 U2 54 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 APR 17 PY 2000 VL 84 IS 16 BP 3718 EP 3721 DI 10.1103/PhysRevLett.84.3718 PG 4 WC Physics, Multidisciplinary SC Physics GA 304VH UT WOS:000086504500054 ER PT J AU Archer, DG Kirklin, DR AF Archer, DG Kirklin, DR TI NIST and standards for calorimetry SO THERMOCHIMICA ACTA LA English DT Article; Proceedings Paper CT International Workshop on the Calibration of Calorimeters CY MAR 19-22, 1998 CL TURIN, ITALY SP CNR, Reg Piemonte, Prov Torino, Comune Torino DE calorimetric standards; sodium chloride; potassium chloride; copper; alpha-aluminum oxide ID ENTHALPY INCREMENT MEASUREMENTS; SYNTHETIC SAPPHIRE ALPHA-AL2O3; THERMODYNAMIC PROPERTIES; NACL+H2O SYSTEM; TEMPERATURE-SCALE; 4.5 K; 350 K; NACL(CR) AB The present article describes briefly some of NISTs more recent work on calorimetric standards. New reference-quality measurements of the enthalpy of solution of aqueous sodium chloride, obtained with an adiabatic solution calorimeter, are presented and compared to a previous equation of state for NaCl(aq). Other calorimetric standards that are discussed are potassium chloride used for solution calorimetry and reference materials used for calibration of enthalpy-increment and heat-capacity calorimeters, namely synthetic sapphire (alpha-Al2O3) and copper. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Archer, DG (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 100 Bur Dr,Stop 8381, Gaithersburg, MD 20899 USA. NR 19 TC 22 Z9 25 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-6031 J9 THERMOCHIM ACTA JI Thermochim. Acta PD APR 17 PY 2000 VL 347 IS 1-2 BP 21 EP 30 DI 10.1016/S0040-6031(99)00426-8 PG 10 WC Thermodynamics; Chemistry, Analytical; Chemistry, Physical SC Thermodynamics; Chemistry GA 299XM UT WOS:000086223800005 ER PT J AU Spivakovsky, CM Logan, JA Montzka, SA Balkanski, YJ Foreman-Fowler, M Jones, DBA Horowitz, LW Fusco, AC Brenninkmeijer, CAM Prather, MJ Wofsy, SC McElroy, MB AF Spivakovsky, CM Logan, JA Montzka, SA Balkanski, YJ Foreman-Fowler, M Jones, DBA Horowitz, LW Fusco, AC Brenninkmeijer, CAM Prather, MJ Wofsy, SC McElroy, MB TI Three-dimensional climatological distribution of tropospheric OH: Update and evaluation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID GENERAL-CIRCULATION MODEL; ORGANIC-COMPOUND EMISSIONS; CHEMICAL TRACER MODEL; IN-SITU MEASUREMENTS; CARBON-MONOXIDE; BOUNDARY-LAYER; NONMETHANE HYDROCARBONS; METHYL CHLOROFORM; ATMOSPHERIC METHANE; NITRIC-OXIDE AB A global climatological distribution of tropospheric OH is computed using observed distributions of O-3, H2O, NOt (NO2+NO+2N(2)O(5)+NO3+HNO2+HNO4), CO, hydrocarbons, temperature, and cloud optical depth. Global annual mean OH is 1.16 x 10(6) molecules cm(-3) (integrated with respect to mass of air up to 100 hPa within +/-32 degrees latitude and up to 200 hPa outside that region). Mean hemispheric concentrations of OW are nearly equal, While global mean OH increased by 33% compared to that from Spivakovsky et al. [1990], mean loss frequencies of CH3CCl3 and CH4 increased by only 23% because a lower fraction of total OH resides in the lower troposphere in the present distribution. The value for temperature used for determining lifetimes of hydrochlorofluorocarbons (HCFCs) by scaling rate constants [Prather and Spivakovsky, 1990] is revised from 277 It to 272 K. The present distribution of OH is consistent within a few percent with the current budgets of CH3CCl3 and HCFC-22. For CH3CCl3, it results in a lifetime of 4.6 years, including stratospheric and ocean sinks with atmospheric lifetimes of 43 and 80 years, respectively. For HCFC-22, the lifetime is 11.4 years, allowing for the stratospheric sink with an atmospheric lifetime is 11.4 years, allowing for the stratospheric sink with an atmospheric lifetime of 229 years. Corrections suggested by observed levels of CH2Cl2 (annual means) depend strongly on the rate of interhemispheric mixing in the model, An increase in OH in the Northern Hemisphere by 20% combined with a decrease in the southern tropics by 25% is suggested if this rate is at its upper limit consistent with observations of CFCs and Kr-85. For the lower limit, observations of CH2Cl2 imply an increase in OH in the Northern Hemisphere by 35% combined with a decrease in OH in the southern tropics by 60%. However, such large corrections are inconsistent with observations for (CO)-C-14 in the tropics and For the interhemispheric gradient; of CH3CCl3. Industrial sources of CH2Cl2 are sufficient for balancing its budget. The available tests do not establish significant errors in OH except for a possible underestimate in winter in the northern and southern tropics by 15-20% and 10-15%, respectively, and an overestimate in southern extratropics by similar to 25%. Observations of seasonal variations of CH3CCl3, CH2Cl2, (CO)-C-14, and C2H6 offer no evidence for higher levels of OH in the southern than in the northern extratropics. It is expected that in the next few years the latitudinal distribution and annual cycle of CH3CCl3 will be determined primarily by its loss frequency, allowing for additional constraints for OH on scales smaller than global. C1 Harvard Univ, DEAS, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Max Planck Inst Chem, D-55128 Mainz, Germany. Univ Calif Irvine, Dept Geosci, Irvine, CA USA. RP Spivakovsky, CM (reprint author), Harvard Univ, DEAS, 29 Oxford St,Pierce Hall, Cambridge, MA 02138 USA. EM cms@io.harvard.edu; jal@io.harvard.edu; smontzka@cmdl.noaa.gov; ybalkanski@cea.fr; mfowler@lgmtech.com; dbj@io.harvard.edu; lwh@gfdl.gov; acf@io.harvard.edu; carlb@mpch-mainz.mpg.de; mprather@uci.edu; scw@io.harvard.edu; mbm@io.harvard.edu RI 欧阳, 冰洁/G-2925-2011; Brenninkmeijer, Carl/B-6860-2013; Horowitz, Larry/D-8048-2014; Balkanski, Yves/A-6616-2011; Jones, Dylan/O-2475-2014; OI Horowitz, Larry/0000-0002-5886-3314; Balkanski, Yves/0000-0001-8241-2858; Jones, Dylan/0000-0002-1935-3725; Montzka, Stephen/0000-0002-9396-0400 NR 186 TC 456 Z9 461 U1 3 U2 56 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 APR 16 PY 2000 VL 105 IS D7 BP 8931 EP 8980 DI 10.1029/1999JD901006 PG 50 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400007 ER PT J AU Houweling, S Dentener, F Lelieveld, J Walter, B Dlugokencky, E AF Houweling, S Dentener, F Lelieveld, J Walter, B Dlugokencky, E TI The modeling of tropospheric methane: How well can point measurements be reproduced by a global model? SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID 1,1,1-TRICHLOROETHANE METHYL CHLOROFORM; ATMOSPHERIC TRANSPORT MODEL; GROWTH-RATE; MAUNA-LOA; NORTHERN-HEMISPHERE; SULFUR-HEXAFLUORIDE; DRAMATIC DECREASE; EMISSIONS; CHEMISTRY; TRACER AB Global model simulations of tropospheric methane are presented, using state of the art representations of its terrestrial sources. Parameters critical for its tropospheric sink and transport have been evaluated using CH3CCl3 and SF6. We assess how well available methane measurements can be reproduced by the model, and how model and measurements can most efficiently be compared. Using European Centre for Medium-Range Weather Forecasts reanalyzed meteorological fields, direct comparisons between model results and flask or in situ measurements are presented, as opposed to comparing multiannual averaged seasonal cycles and trends as was done in previous studies. When comparing monthly means derived from weekly flask sampling and the model, the agreement at stations as Bermuda East and Mace Head is improved if, instead of sampling the model at each model time step, samples are taken at the same times as the measurements were taken. A method is presented to estimate the potential influence of subgrid variability using a marked tracer that is emitted in the vicinity of observational stations only. From the contribution of this tracer to the computed methane concentration at a particular station, the potential contribution of subgrid sources can be estimated. Radon 222 is used to select baseline conditions in the model to improve the comparability of model and measurements when a clean air sector is selected for sampling. Comparisons of model results and measurements, screened for local influences and artifacts of wind sector selection, indicate that the model has in particular difficulty reproducing seasonal cycles at higher latitude stations of the Northern Hemisphere. Sensitivity simulations show that the simulated annual variation at these stations is sensitive to the parameterization of wetland emissions. Also at the South China Sea, model simulations point to errors in the representation of methane sources. Marked tracer simulations indicate that this is most likely related to emissions from natural wetlands and rice paddies, in line with recent inverse modeling and up-scaling estimates. C1 Univ Utrecht, Inst Marine & Atmospher Res, NL-3584 CC Utrecht, Netherlands. Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Houweling, S (reprint author), Univ Utrecht, Inst Marine & Atmospher Res, Princetonplein 5, NL-3584 CC Utrecht, Netherlands. EM s.houweling@phys.uu.nl; f.j.dentener@phys.uu.nl; j.lelieveld@phys.uu.nl RI Pfister, Gabriele/A-9349-2008; Lelieveld, Johannes/A-1986-2013 NR 74 TC 53 Z9 55 U1 1 U2 12 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 APR 16 PY 2000 VL 105 IS D7 BP 8981 EP 9002 DI 10.1029/1999JD901149 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400008 ER PT J AU Cowling, EB Chameides, WL Kiang, CS Fehsenfeld, FC Meagher, JF AF Cowling, EB Chameides, WL Kiang, CS Fehsenfeld, FC Meagher, JF TI Introduction to special section: Southern Oxidants Study Nashville/Middle Tennessee Ozone Study, Part 2 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article C1 N Carolina State Univ, Coll Forest Resources, Raleigh, NC 27605 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Cowling, EB (reprint author), N Carolina State Univ, Coll Forest Resources, Raleigh, NC 27605 USA. EM ellis_cowling@ncsu.edu; wcham@eas.gatech.edu; chia.kiang@eas.gatech.edu; fcf@al.noaa.gov; jmeagher@al.noaa.gov RI Fehsenfeld, Frederick/I-4876-2013 NR 9 TC 8 Z9 8 U1 0 U2 0 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 APR 16 PY 2000 VL 105 IS D7 BP 9075 EP 9077 DI 10.1029/1999JD901190 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400014 ER PT J AU Goldan, PD Parrish, DD Kuster, WC Trainer, M McKeen, SA Holloway, J Jobson, BT Sueper, DT Fehsenfeld, FC AF Goldan, PD Parrish, DD Kuster, WC Trainer, M McKeen, SA Holloway, J Jobson, BT Sueper, DT Fehsenfeld, FC TI Airborne measurements of isoprene, CO, and anthropogenic hydrocarbons and their implications SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHEASTERN UNITED-STATES; MIDDLE TENNESSEE OZONE; VOLATILE ORGANIC-COMPOUNDS; METHYL VINYL KETONE; OXIDATION-PRODUCTS; BIOGENIC HYDROCARBONS; NATURAL HYDROCARBONS; SOUTHERN OXIDANTS; CARBON-MONOXIDE; REGIONAL OZONE AB Measurements of the mixing ratios of light hydrocarbons (greater than or equal to C-6) were made aboard the National Oceanic and Atmospheric Administration Lockheed Orion WP-3 aircraft during June and July of 1994 and 1995 during a series of flights over the region around Nashville, Tennessee. The measurements were carried out as part of the Nashville/ Middle Tennessee Study of the Southern Oxidant Study (SOS) whose purpose was to describe the sources, variation, and distribution of ozone and its precursors in the southeastern United States during the summer season. The spatial (altitude and latitude) distribution of isoprene and anthropogenic nonmethane hydrocarbons (NMHCs) is described. The isoprene distribution measured within the planetary boundary layer over the region is compared to the recent inventories. The correlations between the various anthropogenic hydrocarbons are used to demonstrate the combined influence of OH photochemistry and dilution on their concentrations. Finally, the distributions of those NMHCs that were measured are compared to those of CO and methane and discussed in terms their implications for odd hydrogen photochemistry and our understanding of regional ozone production. In the boundary layer, OH reactions are dominated by isoprene in the southern part of the region explored and by CO and methane in the northern part. The other measured NMHCs are seen to play only a minor role in ozone production in the nonurban atmosphere. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, CIRES, Boulder, CO 80301 USA. RP Goldan, PD (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM pgoldan@al.noaa.gov RI Kuster, William/E-7421-2010; Parrish, David/E-8957-2010; Holloway, John/F-9911-2012; Trainer, Michael/H-5168-2013; McKeen, Stuart/H-9516-2013; Fehsenfeld, Frederick/I-4876-2013; OI Kuster, William/0000-0002-8788-8588; Parrish, David/0000-0001-6312-2724; Holloway, John/0000-0002-4585-9594; Jobson, Bertram/0000-0003-1812-9745 NR 50 TC 49 Z9 49 U1 3 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 16 PY 2000 VL 105 IS D7 BP 9091 EP 9105 DI 10.1029/1999JD900429 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400016 ER PT J AU McMillen, RT Gunter, RL Luke, WT Watson, TB AF McMillen, RT Gunter, RL Luke, WT Watson, TB TI Ozone fluxes obtained with the NOAA Twin Otter during the Southern Oxidants Study SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DEPOSITION; AIRCRAFT; EXCHANGE; AIRBORNE; LAYER AB During June and July of 1995, as part of the Southern Oxidants Study (SOS), the National Oceanic and Atmospheric Administration (NOAA) instrumented Twin Otter research aircraft made meteorological and chemical measurements to characterize atmospheric conditions in and around the Nashville, Tennessee, area. In addition to these characterization studies, the aircraft measured the vertical fluxes of ozone, water vapor, heat, and momentum in the study area, at altitudes between 100 and 2500 m above ground level (agl) along transects a few kilometers downwind of the urban area, and extending crosswind well outside of the urban plume. During all low-level transects, fluxes were measured over short length scales in order to assess their spatial variability. Several powerplant plumes impacted the local region, creating a complex scenario for analysis of ozone production and deposition processes. Deposition velocities derived from aircraft observations near the ground were found to be in reasonable agreement with values estimated by a deposition velocity model applied along the transects. The results are difficult to reconcile with expectations unless it is assumed that the area of the measurements was susceptible to considerable advection and/or effects of plume chemistry and spatial heterogeneity. Additional studies of this kind are now planned, in situations that are less complex. C1 NOAA, Atmospher Turbulence & Diffus Div, Air Resources Lab, Oak Ridge, TN 37831 USA. NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. NOAA, Field Res Div, Air Resources Lab, Idaho Falls, ID 83402 USA. RP McMillen, RT (reprint author), NOAA, Atmospher Turbulence & Diffus Div, Air Resources Lab, POB 2456, Oak Ridge, TN 37831 USA. EM mcmillen@atdd.noaa.gov; gunter@atdd.noaa.gov; winston.luke@noaa.gov; tom.watson@noaa.gov RI Luke, Winston/D-1594-2016 OI Luke, Winston/0000-0002-1993-2241 NR 21 TC 2 Z9 2 U1 0 U2 3 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 APR 16 PY 2000 VL 105 IS D7 BP 9121 EP 9135 DI 10.1029/1999JD900786 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400018 ER PT J AU Baumann, K Williams, EJ Angevine, WM Roberts, JM Norton, RB Frost, GJ Fehsenfeld, FC Springston, SR Bertman, SB Hartsell, B AF Baumann, K Williams, EJ Angevine, WM Roberts, JM Norton, RB Frost, GJ Fehsenfeld, FC Springston, SR Bertman, SB Hartsell, B TI Ozone production and transport near Nashville, Tennessee: Results from the 1994 study at New Hendersonville SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHEASTERN UNITED-STATES; OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; BOUNDARY-LAYER; PHOTOSTATIONARY STATE; BIOGENIC HYDROCARBONS; REACTIVE NITROGEN; REGIONAL OZONE; NIWOT RIDGE; MODEL; NO2 AB During the summer of 1994 the photochemical production of ozone and the relation of this production to the photochemical precursors were studied at a suburban ground site near Nashville, Tennessee. The study, which was carried out as part of the Southern Oxidant Study (SOS), investigated the ozone produced by urban outflow during one period of high photochemical activity around July 1, 1994. Estimates of the instantaneous rate of in situ ozone production, P(O-3), are inferred from deviations of the photostationary state (PSS) for clear-sky conditions. The biggest contributor to the large errors in P(O-3) are the systematic errors in the derived, nor measured, j(NO2) levels. Ozone entrainment from aloft has been quantified by simple subtraction of calculated production and loss terms from the observed rate of ozone change. The uncertainty of this derived transport term was estimated to a factor of 2 at best and 2 orders of magnitude at worst. Entrainment provides a substantial contribution to the observed increase of [O-3] (similar to 20 ppbv h(-1)) in the mornings between 0700 and 1000 Central Standard Time (CST being 1 hour behind LT) when advection can be neglected. An average entrainment velocity of 1.5-2 cm s(-1) agreed within 30 to 50% with a result found from another, completely independent study. P(O-3) dominates the observed [O-3] increase from 1000 CST until early afternoon, when entrainment weakens and even turns into an effective ozone loss term due to cloud venting processes. The July 1 case clearly demonstrates that the morning ozone entrainment occurs on a more regional scale covering the entire study area, whereas the midday ozone exceedance was spatially more confined to the area covered by the advective outflow of the chemically processed Nashville urban plume. The data show that the entrained [O-3]-rich air aloft is the remnant of the previous day's local ozone buildup and subsequent nocturnal advective redistribution. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Adv Study Program, Boulder, CO 80307 USA. Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. Western Michigan Univ, Dept Chem, Kalamazoo, MI 49008 USA. Atmospher Res & Anal Inc, Plano, TX 75093 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Baumann, K (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, 221 Bobby Dodd Way,OCE 205, Atlanta, GA 30332 USA. EM kb@eas.gatech.edu; eric@al.noaa.gov; wayne@al.noaa.gov RI Roberts, James/A-1082-2009; Williams, Eric/F-1184-2010; Angevine, Wayne/H-9849-2013; Frost, Gregory/I-1958-2013; Fehsenfeld, Frederick/I-4876-2013 OI Roberts, James/0000-0002-8485-8172; Angevine, Wayne/0000-0002-8021-7116; NR 47 TC 22 Z9 22 U1 0 U2 0 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 APR 16 PY 2000 VL 105 IS D7 BP 9137 EP 9153 DI 10.1029/1999JD901017 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400019 ER PT J AU Tonnesen, GS Dennis, RL AF Tonnesen, GS Dennis, RL TI Analysis of radical propagation efficiency to assess ozone sensitivity to hydrocarbons and NOx 1. Local indicators of instantaneous odd oxygen production sensitivity SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ACID DEPOSITION MODEL; CHEMICAL AMPLIFIER; PEROXY-RADICALS; BOUNDARY-LAYER; STATE; PHOTOCHEMISTRY; AMPLIFICATION; MECHANISMS; CHEMISTRY AB We used a simple trajectory model and a three-dimensional grid model to evaluate several indicators that can be used to predict the sensitivity of odd oxygen production (P(O-x)) to changes in emissions of anthropogenic nonmethane hydrocarbons (VOC) and nitrogen oxides (NOx = NO + NO2). To perform the evaluation, we augmented the model to include new diagnostic outputs such as rates of P(O-x), rates of conversion of NOx to unreactive nitrogen, and radical chain length. We used the new diagnostic outputs to explain the model-predicted sensitivity of P(O-x) to changes in VOC and NOx emissions. We found that the ozone ridgeline, which distinguishes between NOx-limited and radical-limited conditions, is determined by a ridgeline of maximum OH chain length. We examined the radical propagation reactions which affect OH chain length, and we developed four indicators related to radical propagation efficiency: I(HC,NO2) which approximates the fraction of OH that reacts with hydrocarbons; I(NO,RO2) which approximates the fraction of HO2 that reacts with NO; the ratio of [O-3]/[NOx] which affects the balance between radical initiation and propagation; and [HO2] which is the dominant term in P(H2O2)/P(HNO3). Each of these indicators distinguishes conditions in which instantaneous P(O-x) is primarily sensitive to either NOx emissions reductions or VOC emissions reductions. C1 Univ Calif Riverside, Coll Engn, Ctr Environm Res & Technol, Riverside, CA 92521 USA. NOAA, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. RP Tonnesen, GS (reprint author), Univ Calif Riverside, Coll Engn, Ctr Environm Res & Technol, Mail Code 022, Riverside, CA 92521 USA. EM tonnesen@cert.ucr.edu; rdennis@hpcc.epa.gov NR 37 TC 49 Z9 50 U1 5 U2 15 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 APR 16 PY 2000 VL 105 IS D7 BP 9213 EP 9225 DI 10.1029/1999JD900371 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400025 ER PT J AU Tonnesen, GS Dennis, RL AF Tonnesen, GS Dennis, RL TI Analysis of radical propagation efficiency to assess ozone sensitivity to hydrocarbons and NOx 2. Long-lived species as indicators of ozone concentration sensitivity SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ACID DEPOSITION MODEL AB We used an analysis of radical propagation efficiency and OH chain length in a simple trajectory model to propose combinations of long-lived species that distinguish conditions in which O-3 concentration ([O-3]) is NOx-limited and radical-limited. We further examined these indicators in a three-dimensional grid model. We proposed several new indicators including [H2O2]/([O-3] + [NO2]), [O-3]/[NOx], and a measure using the OH rate constant weighted concentrations of NO2 and hydrocarbons. Our analysis also supports the use of several indicators previously proposed by other researchers, including [O-3]/[HNO3] and [H2O2]/[HNO3]. We found that [HCHO]/[NO2] was more useful than the previously proposed [HCHO]/[NOy]. We found that the indicators easily distinguished extremely NOx-, limited or extremely radical-limited regimes but did not reliably distinguish conditions closer to the transition between these two regimes. We propose that a combined analysis using photochemical model simulations and a large set of indicators of both [O-3] sensitivity and local odd oxygen production (P(O-x)) sensitivity to VOC and NOx provides the most complete and useful description of [O-3] sensitivity. Time series of the indicators, at least from midmorning to late afternoon, provide useful information about the evolution of [O-3] Sensitivity during the day. Values of the indicators change depending on the [O-3] level due in part to the effects of miscellaneous OH and HO2 termination reactions and to the effects of the composition of the HC mixture on P(O-x). Further evaluation of these indicators using modeling studies, measurements, and test cases with NOx or VOC emissions changes are needed to determine how reliably they distinguish NOx- and radical-limited conditions. C1 Univ Calif Riverside, Coll Engn, Ctr Environm Res & Technol, Riverside, CA 92521 USA. Natl Ocean & Atmospher Adm, Atmospher Sci Modeling Div, Res Triangle Pk, NC USA. US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. RP Tonnesen, GS (reprint author), Univ Calif Riverside, Coll Engn, Ctr Environm Res & Technol, Riverside, CA 92521 USA. EM tonnesen@cert.ucr.edu; rdennis@hpcc.epa.gov NR 19 TC 43 Z9 45 U1 3 U2 12 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 APR 16 PY 2000 VL 105 IS D7 BP 9227 EP 9241 DI 10.1029/1999JD900372 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FJ UT WOS:000086586400026 ER PT J AU Xu, JD Locascio, L Gaitan, M Lee, CS AF Xu, JD Locascio, L Gaitan, M Lee, CS TI Room-temperature imprinting method for plastic microchannel fabrication SO ANALYTICAL CHEMISTRY LA English DT Article ID GREEN-FLUORESCENT PROTEIN; CAPILLARY ELECTROPHORESIS; MICROFLUIDIC NETWORKS; DNA; EXPRESSION; SYSTEMS; CHIPS; FLOW; MANIPULATION; SEPARATIONS AB A new plastic imprinting method using a silicon template is demonstrated. This new approach obviates the necessity of heating the plastic substrate during the stamping process, thus improving the device yield from similar to 10 devices to above 100 devices per template. The dimensions of the imprinted microchannels were found to be very reproducible, with variations of less than 2%. The channel depths were dependent on the pressures applied and the materials used. Rather than bonding the open channels with another piece of plastic, a flexible and adhesive poly(dimethylsiloxane) film is used to seal the microchannels, which offers many advantages. As an application, isoelectric focusing of green fluorescence protein on these plastic microfluidic devices is illustrated. C1 Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Lee, CS (reprint author), Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. NR 33 TC 121 Z9 124 U1 3 U2 26 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 APR 15 PY 2000 VL 72 IS 8 BP 1930 EP 1933 DI 10.1021/ac991216q PG 4 WC Chemistry, Analytical SC Chemistry GA 304RD UT WOS:000086497200031 ER PT J AU Zhou, ST Gelman, ME Miller, AJ McCormack, JP AF Zhou, ST Gelman, ME Miller, AJ McCormack, JP TI An inter-hemisphere comparison of the persistent stratospheric polar vortex SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANTARCTIC OZONE; BREAKING; RECOVERY AB Based on 19 years(1979-1998) of NCEP/NCAR reanalyses data and potential vorticity (PV) area diagnostics, we Found that in the southern hemisphere (SH) the polar vortex has lasted about two weeks longer in the 1990s than in the early 1980s and the northern hemisphere (NH) polar vortex has lasted four weeks longer. The SH vortex persisted within the layer(12-22 km) with almost complete ozone loss, but did not persist at higher altitudes where ozone was not depleted. However, the NH vortex persisted in a broader vertical range not limited to the ozone-depletion layer. We show that wave activity has weakened in recent years in the NH, but not in the SH. The springtime Antarctic ozone hole seems to be the main cause for the SH polar vortex persistence, while the cause for the NH vortex persistence involves changes in polar ozone as well as changes in dynamics. C1 NOAA, Natl Ctr Environm Predict, Washington, DC 20250 USA. Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA. Res & Data Syst Corp, Greenbelt, MD 20768 USA. RP Zhou, ST (reprint author), W-NP53,808,5200 Auth Rd, Washington, DC 20233 USA. OI McCormack, John/0000-0002-3674-0508 NR 13 TC 50 Z9 57 U1 0 U2 4 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 APR 15 PY 2000 VL 27 IS 8 BP 1123 EP 1126 DI 10.1029/1999GL011018 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 305HW UT WOS:000086534700011 ER PT J AU Ribera, P Garcia, R Diaz, HF Gimeno, L Hernandez, E AF Ribera, P Garcia, R Diaz, HF Gimeno, L Hernandez, E TI Trends and interannual oscillations in the main sea-level surface pressure patterns over the Mediterranean, 1955-1990 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTH-ATLANTIC OSCILLATION; ASSOCIATION AB The evolution of the main sea level pressure patterns built from Rotated Principal Component Analysis (RPCA) over a domain centered on the Mediterranean for the period 1955-1990 is examined. The annual cycle and the interannual variations are analyzed using Singular Spectrum Analysis (SSA) and three methods of spectral analysis, to detect trends and oscillations in the main patterns. The dominant patterns show oscillations characteristic of NAO and SO. This paper shows that NAO and SO seem to be correlated in a band centered in 6-8 years and that SLP behaviour over the region is dominated by QBO (which controls the oscillation frequency) while NAO modulates the amplitudes. C1 NOAA, ERL, CDC, Boulder, CO 80303 USA. Univ Complutense Madrid, Fac CC Fis, Dpto Fis Tierra 2, E-28040 Madrid, Spain. Univ Vigo, Ourense 32003, Spain. RP Ribera, P (reprint author), NOAA, ERL, CDC, 325 Broadway, Boulder, CO 80303 USA. RI GIMENO, LUIS/B-8137-2008; OI Ribera, Pedro/0000-0002-6432-1554 NR 13 TC 21 Z9 21 U1 2 U2 3 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 APR 15 PY 2000 VL 27 IS 8 BP 1143 EP 1146 DI 10.1029/1999GL010899 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 305HW UT WOS:000086534700016 ER PT J AU Misakian, M Wang, YC AF Misakian, M Wang, YC TI Calculation of ion energy distributions from radio frequency plasmas using a simplified kinetic approach SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INDUCTIVELY-COUPLED PLASMA; REFERENCE CELL; DISCHARGES; DYNAMICS; SHEATH; ARGON AB Using an elementary kinetic approach, a procedure is described for calculating ion energy distributions (IEDs) from radio frequency (rf) plasmas. The calculated distributions, which are in the form of histograms, are used to fit experimental argon and CF3+ IEDs measured in a Gaseous Electronics Conference rf reactor modified to operate in a pulsed inductively coupled mode. Given the average plasma potential profile and its time dependence, the calculation incorporates a number of parameters used in more comprehensive treatments of the problem to determine the shape of the IED. The reverse calculation that determines the average potential profile, given an experimental IED, cannot be uniquely done, but some insights may be gained in some cases if a sufficient number of plasma related parameters are known, e.g., the shape and amplitude of the rf modulation. The results of the calculation indicate that argon ions forming the IEDs during the bright (H) mode come nearly exclusively from a presheath region that extends far into the interior of the plasma. The calculations also suggest that the CF3+ ions forming the IEDs observed during the dim (E) mode may preferentially come from near the "edge" of the bulk plasma. Possible significances of this difference are noted. (C) 2000 American Institute of Physics. [S0021-8979(00)06908-5]. C1 Natl Inst Stand & Technol, Div Elect, Gaithersburg, MD 20899 USA. RP Misakian, M (reprint author), Natl Inst Stand & Technol, Div Elect, Gaithersburg, MD 20899 USA. NR 20 TC 6 Z9 6 U1 0 U2 5 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 APR 15 PY 2000 VL 87 IS 8 BP 3646 EP 3653 DI 10.1063/1.372394 PG 8 WC Physics, Applied SC Physics GA 298YU UT WOS:000086169500005 ER PT J AU Mujica, V Roitberg, AE Ratner, M AF Mujica, V Roitberg, AE Ratner, M TI Molecular wire conductance: Electrostatic potential spatial profile SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRONIC TRANSPARENCY; COULOMB-BLOCKADE; QUANTUM DOTS; TRANSPORT; DEVICES; STATES AB We have studied the effect of the electrostatic potential on the current across a one-dimensional tight-binding molecular wire by solving self-consistently the Poisson and Schrodinger equations. The results indicate that electrostatic effects on the current are very important in the nonlinear regime. They manifest themselves through a strong variation of the voltage drop in the interfacial region compared to the linear ramp expected in the absence of charge in the wire and also in the nature of the current-voltage characteristics. (C) 2000 American Institute of Physics. [S0021- 9606(00)71215-3]. C1 Cent Univ Venezuela, Fac Ciencias, Escuela Quim, Caracas 1020A, Venezuela. Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. RP Mujica, V (reprint author), Cent Univ Venezuela, Fac Ciencias, Escuela Quim, Apartado 47102, Caracas 1020A, Venezuela. RI Roitberg, Adrian/A-2378-2009 NR 41 TC 169 Z9 170 U1 4 U2 10 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 2000 VL 112 IS 15 BP 6834 EP 6839 DI 10.1063/1.481258 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 301EV UT WOS:000086297000041 ER PT J AU van den Dool, HM Saha, S Johansson, A AF van den Dool, HM Saha, S Johansson, A TI Empirical orthogonal teleconnections SO JOURNAL OF CLIMATE LA English DT Article ID HEIGHT FIELD; FORECASTS; ANALOGS; SKILL; LONG AB A new variant is proposed for calculating functions empirically and orthogonally from a given space-time dataset. The method is rooted in multiple linear regression and yields solutions that are orthogonal in one direction, either space or time. In normal setup, one searches for that point in space, the base point (predictor). which, by linear regression, explains the most of the variance at all other points (predictands) combined. The first spatial pattern is the regression coefficient between the base point and all other points, and the first time series is taken to be the time series of the raw data at the base point. The original dataset is next reduced; that is, what has been accounted for by the first mode is subtracted out. The procedure is repeated exactly as before for the second, third, etc., modes. These new functions are named empirical orthogonal teleconnections (EOTs). This is to emphasize the similarity of EOT to both teleconnections and (biorthogonal) empirical orthogonal functions (EOFs). One has to choose the orthogonal direction for EOT. In the above description of the normal space-time setup, picking successive base points in space, the time series are orthogonal. One can reverse the role of time and space-in this case one picks base points in time, and the spatial maps will be orthogonal. If the dataset contains biorthogonal modes, the EOTs are the same for both setups and are equal to the EOFs. When applied to four commonly used datasets, the procedure was found to work well in terms of explained variance (EV) and in terms of extracting familiar patterns. In all examples the EV for EOTs was only slightly less than the optimum obtained by EOF. A numerical recipe was given to calculate EOF, starting from EOT as an initial guess. When subjected to cross validation the EOTs seem to fare well in terms of explained variance on independent data las good as EOF). The EOT procedure can be implemented very easily and has, for some (but not all) applications, advantages over EOFs. These novelties, advantages, and applications include the following. 1) One can pick certain modes (or base point) first-the order of the EOTs is free, and there is a near-infinite set of EOTs. 2) EOTs are linked to specific points in space or moments in time. 3) When linked to Row at specific moments in time, the EOT modes have undeniable physical reality. 4) When linked to flow at specific moments in time, EOTs appear to be building blocks for empirical forecast methods because one can naturally access the time derivative. 5) When linked to specific points in space, one has a rational basis to define strategically chosen points such that an analysis of the whole domain would benefit maximally from observations at these locations. C1 NOAA, NWS, NCEP, Climate Predict Ctr, Washington, DC 20233 USA. NOAA, NWS, NCEP, Environm Modeling Ctr, Washington, DC 20233 USA. Swedish Meteorol & Hydrol Inst, S-60176 Norrkoping, Sweden. RP van den Dool, HM (reprint author), WWB, NCEP, Climate Predict Ctr, W-NP51 Rm 604,5200 Auth Rd, Camps Springs, MD 20746 USA. NR 23 TC 66 Z9 66 U1 1 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD APR 15 PY 2000 VL 13 IS 8 BP 1421 EP 1435 DI 10.1175/1520-0442(2000)013<1421:EOT>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306PD UT WOS:000086604300007 ER PT J AU Maes, C Behringer, D AF Maes, C Behringer, D TI Using satellite-derived sea level and temperature profiles for determining the salinity variability: A new approach SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WESTERN EQUATORIAL PACIFIC; SURFACE SALINITY; OCEAN; ENSO; POOL AB We propose a new approach to estimate the vertical variability of the salinity field. The method is based on combined vertical modes of temperature T and salinity S and reconstructs salinity profiles via a weighted least squares procedure. The major advantages of this new approach over using a climatological T-S relationship are that seasonal-to-interannual variability is better taken into account and that the method combines in a consistent way different sources of information such as T and S profiles and sea surface height. The present results estimate the salinity along 165 degrees E in the western Pacific Ocean for the 1993-1998 period and emphasize the importance of the salinity on sea level variability. The reverse problem of estimating the salinity variability along the water column from the satellite-derived sea level and sea surface fields is also investigated. Finally, comparison with in situ salinity observations demonstrates the possibility of extracting useful information about the salinity variability from the TOPEX/Poseidon altimeter data. C1 Natl Ctr Environm Predict, Climate Modeling Branch, Camp Springs, MD 20746 USA. RP Maes, C (reprint author), Natl Ctr Environm Predict, Climate Modeling Branch, NCEP Room 807,5200 Auth Rd, Camp Springs, MD 20746 USA. RI maes, christophe/L-4049-2015 OI maes, christophe/0000-0001-6532-7141 NR 26 TC 48 Z9 54 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 2000 VL 105 IS C4 BP 8537 EP 8547 DI 10.1029/1999JC900279 PG 11 WC Oceanography SC Oceanography GA 305GX UT WOS:000086532000005 ER PT J AU Arrigo, KR DiTullio, GR Dunbar, RB Robinson, DH VanWoert, M Worthen, DL Lizotte, MP AF Arrigo, KR DiTullio, GR Dunbar, RB Robinson, DH VanWoert, M Worthen, DL Lizotte, MP TI Phytoplankton taxonomic variability in nutrient utilization and primary production in the Ross Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SOUTHERN-OCEAN; PIGMENT DISTRIBUTIONS; PHAEOCYSTIS-POUCHETII; ELEMENTAL COMPOSITION; MARINE-PHYTOPLANKTON; SPATIAL PATTERNS; ORGANIC-CARBON; WATER-COLUMN; ICE-EDGE; ANTARCTICA AB Patterns of nutrient utilization and primary productivity (PP) in late austral spring and early summer in the southwestern Ross Sea were characterized with respect to phytoplankton taxonomic composition, polynya dynamics, and upper ocean hydrography during the 1996-1997 oceanographic program Research on Ocean-Atmosphere Variability and Ecosystem Response in the Ross Sea. Phytoplankton biomass in the upper 150 m of the water column ranged from 40 to 540 mg chlorophyll a (Chl a) m(-2), exceeding 200 mg Chl a m-2 everywhere except the extreme northern and eastern boundaries of the Ross Sea polynya. Diatom biomass was greatest in the shallow mixed layers of Terra Nova Bay, while the more deeply mixed waters of the Ross Sea polynya were dominated by Phaeocytstis antarctica. Daily production computed from the disappearance of NO3 (1.14 g C m(-2) d(-1)) and total dissolved inorganic carbon (TDIC, 1.29 g C m(-2) d(-1)) is consistent with estimates made from an algorithm forced with satellite measurements of Chl a (1.25 g C m(-2) d(-1)) and from measurements of C-14 uptake (1.33 g C m(-2) d(-1)). Phytoplankton PP in the Ross Sea averaged 100 g C m(-2) yr(-1) during 1996-1997. Despite the early formation of the Terra Nova Bay polynya the diatom bloom there did not reach its peak PP until middle to late January 1997 (most likely because of more intense wind mixing in November), similar to 6 weeks after the P. antarctica bloom in the Ross Sea polynya had reached the same stage of development. From 70 to 100% of the C and N deficits in the upper 150 m could be accounted for by particulate organic matter, indicating that there had been little dissolved organic matter production or export of particulate material prior to our cruise. This suggests that early in the season, PP and zooplankton grazing are decoupled in the southwestern Ross Sea. The NO3:PO4 disappearance ratio in waters dominated by P. antarctica (19.0 +/- 0.61) was significantly greater than in waters where diatoms were most common (9.52 +/- 0.33), and both were significantly different from the Redfield N:P ratio of 16. Vertical profiles of TDIC suggest that P. antarctica took up 110% more CO2 per mole of PO4 removed than did diatoms, an important consideration for climate models that estimate C uptake from the removal of PO4. C1 Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. Univ Charleston, Grice Marine Lab, Charleston, SC 29412 USA. Stanford Univ, Sch Earth Sci, Dept Geol & Environm Sci, Stanford, CA 94305 USA. San Francisco State Univ, Romberg Tiburon Ctr, Tiburon, CA 94920 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Washington, DC 20233 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Wisconsin, Dept Biol & Microbiol, Oshkosh, WI 54901 USA. RP Arrigo, KR (reprint author), Stanford Univ, Dept Geophys, Mitchell Bldg,Room 360, Stanford, CA 94305 USA. NR 45 TC 106 Z9 109 U1 1 U2 23 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 2000 VL 105 IS C4 BP 8827 EP 8845 DI 10.1029/1998JC000289 PG 19 WC Oceanography SC Oceanography GA 305GX UT WOS:000086532000023 ER PT J AU Weng, FZ Grody, NC AF Weng, FZ Grody, NC TI Retrieval of ice cloud parameters using a microwave imaging radiometer SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-TRANSFER; 183 GHZ; CONVECTIVE SYSTEMS; WATER-CONTENT; PRECIPITATION; RADAR; FREQUENCIES; CRYSTALS; VAPOR AB Based on the radiative transfer theory, the microwave radiance emanating from ice clouds at arbitrary viewing angles is expressed as an analytic function of the cloud ice water path (IWP), the particle effective diameter (D-e), and the particle bulk density (rho(i)). Thus, for a given particle density, the earth-viewing measurements at two frequencies (e.g., 340 and 89 GHz) can provide an estimate of D-e and IWP for submillimeter-size particles. This physical retrieval is rested using data from the Millimeter-wave Imaging Radiometer (MIR). A comparison among MIR, radar, and infrared sensor measurements shows that the MIR frequencies are affected primarily by thick ice clouds such as cirrus anvil and convection. Over highly convective areas, the measurements from 89 to 220 GHz are nearly identical since the scattering by large ice particles aloft approaches the geometric optics limit, which is independent of wavelength. Under these conditions, only the lower MIR frequencies (89 and 150 GHz)are used to retrieve D-e and IWP. In general, the MIR-derived D-e displays a reasonable spatial distribution comparable to the radar and infrared measurements. However, the magnitude of the IWP remains highly uncertain because of insufficient information on the ice particle bulk density. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Washington, DC 20233 USA. RP NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, 4700 Silver Hill Rd,Stop 9910, Washington, DC 20233 USA. EM fweng@nesdis.noaa.gov RI Weng, Fuzhong/F-5633-2010 OI Weng, Fuzhong/0000-0003-0150-2179 NR 34 TC 68 Z9 70 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR 15 PY 2000 VL 57 IS 8 BP 1069 EP 1081 DI 10.1175/1520-0469(2000)057<1069:ROICPU>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306HU UT WOS:000086591900006 ER PT J AU Clark, TL Hall, WD Kerr, RM Middleton, D Radke, L Ralph, FM Neiman, PJ Levinson, D AF Clark, TL Hall, WD Kerr, RM Middleton, D Radke, L Ralph, FM Neiman, PJ Levinson, D TI Origins of aircraft-damaging clear-air turbulence during the 9 December 1992 Colorado downslope windstorm: Numerical simulations and comparison with observations SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GRAVITY-WAVE BREAKING; 3 SPATIAL DIMENSIONS; MOUNTAIN WAVES; MOMENTUM FLUX; LEE WAVES; INSTABILITY; GENERATION; EVOLUTION; FLOW; RASS AB Results from numerical simulations of the Colorado Front Range downslope windstorm of 9 December 1992 are presented. Although this case was not characterized by severe surface winds, the event caused extreme clear-air turbulence (CAT) aloft, as indicated by the severe structural damage experienced by a DC-8 cargo jet at 9.7 km above mean sea level over the mountains. Derailed measurements from the National Oceanic and Atmospheric Administration/Environmental Research Laboratories/Environmental Technology Laboratory Doppler lidar and wind profilers operating on that day and from the Defense Meteorological Satellite Program satellite allow for a uniquely rich comparison between the simulations and observations. Four levels of grid refinement were used in the model. The outer domain used National Centers for Environmental Prediction data for initial and boundary conditions. The finest grid used 200 m in all three dimensions over a 48 km by 48 km section. The range of resolution and domain coverage were sufficient to resolve the abundant variety of dynamics associated with a time-evolving windstorm forced during a frontal passage. This full range of resolution and model complexity was essential in this case. Many aspects of this windstorm are inherently three-dimensional and are not represented in idealized models using either 2D or so-called 2D-3D dynamics. Both the timing and location of wave breaking compared well with observations. The model also reproduced cross-stream wavelike perturbations in the jet stream that compared well with the orientation and spacing of cloud bands observed by satellite and lidar. Model results also show that the observed CAT derives from interactions between these wavelike jet stream disturbances and mountain-forced internal gravity waves. Due to the nearly east-west orientation of the jet stream. these two interacting wave modes were orthogonal to each other. Thermal gradients associated with the intense jet stream undulations generated horizontal vortex tubes (HVTs) aligned with the mean Row. These HVTs remained aloft while they propagated downstream at about the elevation of the aircraft incident, and evidence for such a vortex was seen by the lidar. The model and observations suggest that one of these intense vortices may have caused the aircraft incident. Reports of strong surface gusts were intermittent along the Front Range during the period of this study. The model showed that interactions between the gravity waves and how-aligned jet stream undulations result in isolated occurrences of strong surface gusts in line with observations. The simulations show that strong shears on the upper and bottom surfaces of the jet stream combine to provide an episodic "downburst of turbulence." In the present case, the perturbations of the jet stream provide a funnel-shaped shear zone aligned with the mean flow that acts as a guide for the downward transport of turbulence resulting from breaking gravity waves. The physical picture for the upper levels is similar to the surface gusts described by Clark and Farley resulting from vortex tilting. The CAT feeding into this funnel came from all surfaces of the jet stream with more than half originating from the vertically inclined shear zones on the bottom side of the jet stream. Visually the downburst of turbulence looks similar to a rain shaft plummeting to the surface and propagating out over the plains leaving relatively quiescent conditions behind. C1 NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM clark@ncar.ucar.edu NR 53 TC 67 Z9 71 U1 2 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR 15 PY 2000 VL 57 IS 8 BP 1105 EP 1131 DI 10.1175/1520-0469(2000)057<1105:OOADCA>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306HU UT WOS:000086591900008 ER PT J AU Meredith, JC Amis, EJ AF Meredith, JC Amis, EJ TI LCST phase separation in biodegradable polymer blends: poly(D,L-lactide) and poly(epsilon-caprolactone) SO MACROMOLECULAR CHEMISTRY AND PHYSICS LA English DT Article ID MISCIBILITY; CRYSTALLIZATION; BINARY AB A lower critical solution temperature (LCST) phase transition is reported for blends of the biodegradable polymers poly(D,L-lactide) (PDLA) and poly(epsilon-caprolactone) (PCL). From light scattering measurements the cloud point curve is determined to have a critical temperature of 86 degrees C and a critical concentration of mass fraction 36 wt.-% PCL. Optical microscopy of phase-separated films indicates a spinodal morphology at the critical concentration, and droplet phases at off-critical concentrations. After quenching phase separated blends below the melting temperature of PCL (60 degrees C), the crystallization of PCL is used to positively identify PCL-rich and PDLA-rich phases. When cystallization of PCL follows LCST phase separation, the size, shape, and distribution of crystalline regions can be adjusted by the degree of PCL/PDLA phase separation. This, the LCST phase separation offers a novel method to control microphase structure in biodegradable materials. Applications to control of mechanical and physical properties in tissue engineering scaffolds are discussed in light of the results. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Amis, EJ (reprint author), Natl Inst Stand & Technol, Div Polymers, 100 Bur Dr Stop 8542, Gaithersburg, MD 20899 USA. RI Meredith, Carson/B-3323-2009 OI Meredith, Carson/0000-0003-2519-5003 NR 25 TC 77 Z9 78 U1 3 U2 23 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 1022-1352 J9 MACROMOL CHEM PHYSIC JI Macromol. Chem. Phys. PD APR 14 PY 2000 VL 201 IS 6 BP 733 EP 739 DI 10.1002/(SICI)1521-3935(20000301)201:6<733::AID-MACP733>3.0.CO;2-5 PG 7 WC Polymer Science SC Polymer Science GA 306RB UT WOS:000086608900016 ER PT J AU Wotawa, G Trainer, M AF Wotawa, G Trainer, M TI The influence of Canadian forest fires on pollutant concentrations in the United States SO SCIENCE LA English DT Article ID TRANS-SIBERIAN RAILROAD; CARBON-MONOXIDE; TROPOSPHERIC OZONE; EMISSIONS; TROPICS; IMPACT; CH4; CO AB High carbon monoxide (CO) concentrations from uncertain origins occurred episodically in the southeastern United States during the summer of 1995. We show that these episodes were caused by Large forest fires in Canada. Over a period of 2 weeks, these natural emissions increased CO concentrations in the southeastern United States as well as along the eastern seaboard, a region with one of the world's highest rates of anthropogenic emissions. Within the forest fire plumes, there were abo high concentrations of ozone, volatile organic compounds, and aerosols. These results suggest that the impact of boreal forest fire emissions on air quality in the mid-latitudes of the Northern Hemisphere, where anthropogenic pollutant sources have been considered predominant, needs to be reevaluated. C1 Univ Agr Sci, Inst Meteorol & Phys, A-1180 Vienna, Austria. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Wotawa, G (reprint author), Univ Colorado, CIRES, Boulder, CO 80309 USA. RI Trainer, Michael/H-5168-2013 NR 29 TC 180 Z9 183 U1 6 U2 29 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD APR 14 PY 2000 VL 288 IS 5464 BP 324 EP 328 DI 10.1126/science.288.5464.324 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 303YA UT WOS:000086454300034 ER PT J AU Hsueh, CH Fuller, ER AF Hsueh, CH Fuller, ER TI Analytical modeling of oxide thickness effects on residual stresses in thermal barrier coatings SO SCRIPTA MATERIALIA LA English DT Article DE modeling; thermal barrier coating; thermal expansion; stress ID OXIDATION-INDUCED STRESSES; SCALES; FILMS C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 9 TC 48 Z9 60 U1 2 U2 23 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 APR 14 PY 2000 VL 42 IS 8 BP 781 EP 787 DI 10.1016/S1359-6462(99)00430-3 PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 308DG UT WOS:000086694800008 ER PT J AU Materer, N Goodman, RS Leone, SR AF Materer, N Goodman, RS Leone, SR TI Ion-enhanced etching of Si(100) with molecular chlorine: Neutral and ionic product yields as a function of ion kinetic energy and molecular chlorine flux SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID DYNAMICS SIMULATION; DESORPTION-KINETICS; CONTAINING PLASMAS; SILICON SURFACES; SI; CL2; SEMICONDUCTORS; MECHANISMS; CHEMISTRY; SI(111) AB Time-of-flight mass spectrometry (TOFMS) is used to measure neutral and ionic silicon etch products evolved during argon ion-enhanced etching of room temperature Si(100) with molecular chlorine. The yields of these neutral and ionic etch products are examined as a function of ion energy, ion flux, and molecular chlorine flux. For the neutral products, an Ar+ ion energy range of 275-975 eV is used, while the ionic product measurements are continued down to 60 eV. The atomic Si, SiCl, and SiCl2 neutral etch products are measured without complications due to fragmentation by using 118-nm laser single-photon TOFMS. Atomic Si and SiCl are the major observed etch products. The ionic Si+ and SiCl+ etch products are also measured using TOFMS; however, the SiCl2+ species is not observed. The similarities between neutral and ionic Si and SiCl etch products as a function of various parameters Suggest a model based on direct collisional desorption. For the observed neutral SiCl2 product, the absence of SiCl2+ suggests a different mechanism than that for Si and SiCl. For SiCl2, formation models based on thermal heating or reaction and desorption of neutral species at chemically active surface sites, which are ruled out for Si and SiCl, should be considered. C1 Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Natl Inst Stand & Technol, Quantum Phys Div, 325 Broadway, Boulder, CO 80309 USA. NR 34 TC 2 Z9 2 U1 1 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 APR 13 PY 2000 VL 104 IS 14 BP 3261 EP 3266 DI 10.1021/jp993278q PG 6 WC Chemistry, Physical SC Chemistry GA 306MD UT WOS:000086599700033 ER PT J AU Anderson, MC Norman, JM Meyers, TP Diak, GR AF Anderson, MC Norman, JM Meyers, TP Diak, GR TI An analytical model for estimating canopy transpiration and carbon assimilation fluxes based on canopy light-use efficiency SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE canopy; carbon assimilation; evapotranspiration; light-use efficiency; ALEX ID TEMPERATE GRASSLAND ECOSYSTEM; SURFACE PARAMETERIZATION SIB2; NET PRIMARY PRODUCTION; STOMATAL CONDUCTANCE; SOLAR-RADIATION; LEAF-AREA; FIFE 1989; PHOTOSYNTHESIS; VEGETATION; SOIL AB We develop a simple, analytical model for canopy resistance to canopy-atmosphere gas exchange that is well suited for incorporation into regional-scale land-surface parameterizations. This model exploits the conservative nature of canopy light-use efficiency (LUE) in carbon assimilation that is observed within broad categories of plant species. The model paradigm assumes that under standard environmental conditions, a canopy will operate at the field-measured LUE, but will deviate from this standard efficiency as conditions change. Effective LUE estimates generated by the model respond to variations in atmospheric humidity, CO2 concentration, the composition of solar irradiation (direct versus diffuse beam fractions), and soil moisture content. This modeling approach differs from scaled-leaf parameterizations in that a single estimate of nominal canopy LUE replaces both a detailed mechanistic description of leaf-level photosynthetic processes and the scaling of these processes from the leaf to canopy level. This results in a model that can be evaluated analytically, and is thus computationally efficient and requires few species-specific parameters. Both qualities lend themselves well to regional-and global-scale modeling efforts. For purposes of testing, this canopy resistance submodel has been embedded in the Atmosphere-Land Exchange (ALEX) surface energy balance model. The integrated model generates transpiration and carbon assimilation fluxes that compare well with estimates from iterative mechanistic photosynthetic models, and with Aux measurements made in stands of corn, soybean, prairie grasses, desert shrubs, rangeland, and black spruce. Comparisons between modeled and measured evapotranspiration (LE) and carbon assimilation (A(c)) fluxes yield mean-absolute-percent-differences of 24% (LE) and 33% (A(c)) for hourly daytime fluxes, and 12% (LE) and 18% (A(c)) for daily-integrated fluxes. These comparisons demonstrate robustness over a variety of vegetative and climatic regimes, suggesting that this simple analytical model of canopy resistance will be useful in regional-scale flux evaluations. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Wisconsin, Dept Soil Sci, Madison, WI 53706 USA. NOAA, ATDD, Oak Ridge, TN 37830 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. RP Anderson, MC (reprint author), Univ Wisconsin, Dept Soil Sci, 1525 Observ Dr, Madison, WI 53706 USA. RI Anderson, Martha/C-1720-2015; Meyers, Tilden/C-6633-2016 OI Anderson, Martha/0000-0003-0748-5525; NR 85 TC 109 Z9 114 U1 5 U2 39 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 APR 12 PY 2000 VL 101 IS 4 BP 265 EP 289 DI 10.1016/S0168-1923(99)00170-7 PG 25 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 299GT UT WOS:000086191200004 ER PT J AU Martinis, JM Hilton, GC Irwin, KD Wollman, DA AF Martinis, JM Hilton, GC Irwin, KD Wollman, DA TI Calculation of T-c in a normal-superconductor bilayer using the microscopic-based Usadel theory SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB The Usadel equations give a theory of superconductivity, valid in the diffusive limit, that is a generalization of the microscopic equations of the BCS theory. Because the theory is expressed in a tractable and physical form, even experimentalists can analytically and numerically calculate detailed properties of superconductors in physically relevant geometries. Here, we describe the Usadel equations and review their solution in the case of predicting the transition eeo temperature T-C of a thin normal-superconductor bilayer. We also extend this calculation for thicker bilayers to show the dependence on the resistivity of the films. These results, which show a dependence on both the interface resistance and heat capacity of the films, provide important guidance on fabricating bilayers with reproducible transition temperatures. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Martinis, JM (reprint author), Natl Inst Stand & Technol, 325 Broadway,Mailstop 814-03, Boulder, CO 80303 USA. NR 7 TC 55 Z9 56 U1 0 U2 8 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 APR 11 PY 2000 VL 444 IS 1-2 BP 23 EP 27 DI 10.1016/S0168-9002(99)01320-0 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400007 ER PT J AU Chervenak, JA Grossman, EN Irwin, KD Martinis, JM Reintsema, CD Allen, CA Bergman, DI Moseley, SH Shafer, R AF Chervenak, JA Grossman, EN Irwin, KD Martinis, JM Reintsema, CD Allen, CA Bergman, DI Moseley, SH Shafer, R TI Performance of multiplexed SQUID readout for Cryogenic Sensor Arrays SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB We report on the implementation of a multiplexer that uses superconducting quantum interference devices (SQUIDs) to read out low-impedance cryogenic detectors. Using prototype chips, a circuit was built which interfaces eight input SQUID channels with a close-packed array of eight transition-edge sensor (TES) infrared bolometers. Circuit elements were measured and crosstalk specifications are reported. Digital feedback is employed to flux-lock a single element in the array of SQUIDs. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chervenak, JA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Moseley, Harvey/D-5069-2012 NR 3 TC 11 Z9 11 U1 0 U2 6 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 APR 11 PY 2000 VL 444 IS 1-2 BP 107 EP 110 DI 10.1016/S0168-9002(99)01339-X PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400025 ER PT J AU Wollman, DA Nam, SW Newbury, DE Hilton, GC Irwin, KD Bergren, NF Deiker, S Rudman, DA Martinis, JM AF Wollman, DA Nam, SW Newbury, DE Hilton, GC Irwin, KD Bergren, NF Deiker, S Rudman, DA Martinis, JM TI Superconducting transition-edge-microcalorimeter X-ray spectrometer with 2 eV energy resolution at 1.5 keV SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands DE microcalorimeter; microcalorimeter EDS; energy-dispersive spectrometer; X-ray microanalysis; transition-edge sensor; cryogenic device; energy resolution; X-ray detector; non-dispersive detector ID LINES; AL; MG AB We describe the operation and performance of a prototype microcalorimeter "energy-dispersive'' (non-dispersive) X-ray spectrometer (mu cal EDS) developed at NIST for use in X-ray microanalysis and X-ray astronomy. The low-energy microcalorimeter detector, consisting of an AI-Ag bilayer superconducting transition-edge sensor (TES) in thermal contact with a Pi X-ray absorber, is designed for operation in the energy range from 0-2 keV and is fabricated using a shadow-mask lithographic process. The TES microcalorimeter is cooled by a compact adiabatic demagnetization refrigerator and is mounted on a scanning electron microscope. This device achieves a best energy resolution of 2.0 +/- 0.1 eV at 1.5 keV, as determined from the analysis of digitized X-ray spectra of a complex glass containing many elements. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wollman, DA (reprint author), Natl Inst Stand & Technol, 325 Broadway,Mail Stop 814-03, Boulder, CO 80303 USA. NR 16 TC 81 Z9 81 U1 1 U2 13 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 APR 11 PY 2000 VL 444 IS 1-2 BP 145 EP 150 DI 10.1016/S0168-9002(99)01351-0 PG 6 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400034 ER PT J AU Silver, E Schnopper, H Bandler, S Murray, S Madden, N Landis, D Beeman, J Haller, E Barbera, M Tucker, G Gillaspy, J Takacs, E Porto, J AF Silver, E Schnopper, H Bandler, S Murray, S Madden, N Landis, D Beeman, J Haller, E Barbera, M Tucker, G Gillaspy, J Takacs, E Porto, J TI Laboratory astrophysics and microanalysis with NTD-germanium-based X-ray microcalorimeters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB With the ability to create cosmic plasma conditions in the laboratory it is possible to investigate the dependencies of key diagnostic X-ray lines on density, temperature, and excitation conditions that exist in astrophysical sources with X-ray optics and a high-resolution X-ray microcalorimeter. The same instrumentation call be coupled to scanning electron microscopes or X-ray fluorescence probes to analyze the elemental and chemical composition of electronic, biological, geological and particulate materials. We describe how our microcalorimeter and X-ray optics provide significantly improved capabilities for laboratory astrophysics and microanalysis. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Brown Univ, Providence, RI 02912 USA. Osservatorio Astron Palermo, Palermo, Italy. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Silver, E (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. RI Bandler, Simon/A-6258-2010; OI Bandler, Simon/0000-0002-5112-8106; Barbera, Marco/0000-0002-3188-7420 NR 8 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 156 EP 160 DI 10.1016/S0168-9002(99)01349-2 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400036 ER PT J AU Irwin, KD Hilton, GC Martinis, JM Deiker, S Bergren, N Nam, SW Rudman, DA Wollman, DA AF Irwin, KD Hilton, GC Martinis, JM Deiker, S Bergren, N Nam, SW Rudman, DA Wollman, DA TI A Mo-Cu superconducting transition-edge microcalorimeter with 4.5 eV energy resolution at 6 keV SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB We describe a superconducting transition-edge microcalorimeter with an energy resolution of 4.5 +/- 0.1 eV full-width at half-maximum (FWHM) for Mn K alpha X-rays from an Fe-55 source. The thermometer consists of a photolithographically patterned Mo-Cu superconducting proximity bilayer with a 93 mK transition temperature The device is fabricated on a Si3N4 membrane patterned as a "flyswatter" to control the thermal conductance to the heat bath. The sensor is voltage biased with an on-chip shunt resistor, and the current is measured by a two-stage SQUID amplifier consisting of a single first-stage SQUID and a series-array second-stage SQUID. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Irwin, KD (reprint author), Natl Inst Stand & Technol, 325 Broadway,Mail Stop 814-03, Boulder, CO 80303 USA. NR 6 TC 117 Z9 117 U1 1 U2 9 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 APR 11 PY 2000 VL 444 IS 1-2 BP 184 EP 187 DI 10.1016/S0168-9002(99)01354-6 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400041 ER PT J AU Olsen, J Kirk, EC Thomsen, K van den Brandt, B Lerch, P Scandella, L Zehnder, A Mango, S Ott, HR Huber, M Hilton, GC Martinis, JM AF Olsen, J Kirk, EC Thomsen, K van den Brandt, B Lerch, P Scandella, L Zehnder, A Mango, S Ott, HR Huber, M Hilton, GC Martinis, JM TI First steps towards small arrays of Mo/Au microcalorimeters SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB We are developing small arrays of microcalorimeters based on transition edge sensors made with Mo/Au bilayers deposited on silicon nitride membranes and Au absorbers. The superconducting transition of the bilayers is adjusted to be around 130 mK with a transition width better than a millikelvin by use of the proximity effect between the Au and Mo films. We built a dilution refrigerator and wired it for 2 channel operation in order to study thermal coupling issues between thermometers within the array. The device fabrication procedure as well as preliminary results are presented. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Paul Scherrer Inst, CH-5232 Villigen, Switzerland. ETH Honggerberg, Festkorperphys Lab, CH-8093 Zurich, Switzerland. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Lerch, P (reprint author), Paul Scherrer Inst, CH-5232 Villigen, Switzerland. NR 5 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 253 EP 256 DI 10.1016/S0168-9002(99)01373-X PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400057 ER PT J AU Hellmig, J Gaitskell, RJ Abusaidi, R Cabrera, B Clarke, RM Emes, J Nam, SW Saab, T Sadoulet, B Seitz, D Young, BA AF Hellmig, J Gaitskell, RJ Abusaidi, R Cabrera, B Clarke, RM Emes, J Nam, SW Saab, T Sadoulet, B Seitz, D Young, BA TI The CDMS II Z-sensitive ionization and phonon germanium detector SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands DE solid-state detector; fast phonon sensor; Ge; dark matter; low temperature ID PROPAGATION AB The last year saw major progress in the development of the nuclear-recoil dark matter detector for the Cryogenic Dark Matter Search (CDMS II) experiment. The basic gamma-ray background discrimination is based on ionization yield. However, as shown in separate experiments, surface events and especially electrons also results in low ionization yield due to incomplete charge collection. The two-fold strategy to reduce these unwanted backgrounds was to improve charge collection at the detector surface and to employ fast phonon sensors on Ge. A 250 g Ge detector with an Al Schottky contact on an amorphous Si blocking layer and a Quasiparticle-trap-assisted Electrothermal-feedback Transition-edge (QET) phonon sensor has been characterized. The phonon collection efficiency of the new detector is similar to that of the latest 100 g Si Fast Large Ionization and Phonon (FLIP) detector, which has the same phonon sensor design. The fall times of the phonon pulses are longer and consistent with simulations. The charge collection at the surface is high and very similar to that of smaller test devices and the last revision of Berkeley Large Ionization and Phonon (BLIP) detectors. The four fast non-thermal phonon sensors yield x, y position resolution similar to the Si FLIP detector. A rise time surface effect was demonstrated on both sides of the detector. The effect results in a much more effective rejection of surface events than the rejection based on charge yield alone and therefore improves the sensitivity for a dark matter search. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Stanford Univ, Stanford, CA 94305 USA. Natl Inst Stand & Tech, Gaithersburg, MD USA. Santa Clara Univ, Santa Clara, CA 95053 USA. RP Hellmig, J (reprint author), Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. NR 9 TC 21 Z9 21 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 308 EP 311 DI 10.1016/S0168-9002(99)01403-5 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400070 ER PT J AU Golwala, SR Abusaidi, R Akerib, DS Barnes, PD Bauer, DA Bolozdynya, A Brink, P Cabrera, B Caldwell, DO Castle, JP Clarke, RM Colling, P Crisler, MB Da Silva, A Davies, AK Dixon, R Eichblatt, S Irwin, KD Gaitskell, RJ Haller, EE Hellmig, J Huber, ME Jochum, J Lipschultz, FP Martinis, J Nam, SW Nelson, J Neuhauser, B Perera, TA Isaac, MP Ross, RR Saab, T Sadoulet, B Schnee, RW Shestople, P Shutt, T Smith, A Sonnenschein, AH Spadafora, AL Yellin, S Young, BA AF Golwala, SR Abusaidi, R Akerib, DS Barnes, PD Bauer, DA Bolozdynya, A Brink, P Cabrera, B Caldwell, DO Castle, JP Clarke, RM Colling, P Crisler, MB Da Silva, A Davies, AK Dixon, R Eichblatt, S Irwin, KD Gaitskell, RJ Haller, EE Hellmig, J Huber, ME Jochum, J Lipschultz, FP Martinis, J Nam, SW Nelson, J Neuhauser, B Perera, TA Isaac, MP Ross, RR Saab, T Sadoulet, B Schnee, RW Shestople, P Shutt, T Smith, A Sonnenschein, AH Spadafora, AL Yellin, S Young, BA TI Exclusion limits on the WIMP-nucleon scattering cross-section from the Cryogenic Dark Matter Search SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 8th International Workshop on Low-Temperature Detectors (LTD-8) CY AUG 15-20, 1999 CL DALFSEN, NETHERLANDS SP Technol Fdn, European Space Technol Ctr, Space Res Org Netherlands AB The Cryogenic Dark Matter Search (CDMS) employs massive ionization- and phonon-mediated detectors to search for WIMPs via their elastic scattering interactions with nuclei while discriminating against interactions by other background particles. Limits on the WIMP-nucleon scattering cross-section, based on 3.1 kg d of exposure, exclude new parameter space in the 10-30 GeV WIMP mass region and also a portion of the region allowed by the DAMA annual modulation search (Bernabei, Phys. Lett. 450 (1999) 448). (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Colorado, Dept Phys, Denver, CO 80217 USA. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94132 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. RP Golwala, SR (reprint author), Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. RI Huber, Martin/B-3354-2011 NR 12 TC 32 Z9 32 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD APR 11 PY 2000 VL 444 IS 1-2 BP 345 EP 349 DI 10.1016/S0168-9002(99)01388-1 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 310JU UT WOS:000086823400079 ER PT J AU Crawford, TM Kabos, P Silva, TJ AF Crawford, TM Kabos, P Silva, TJ TI Coherent control of precessional dynamics in thin film permalloy SO APPLIED PHYSICS LETTERS LA English DT Article AB We demonstrate a method of eliminating overshoot and ringing in magnetization dynamics when the system bandwidth includes the intrinsic ferromagnetic resonance (FMR). The method employs staggered step excitation for the cancellation of FMR oscillations while maximizing the risetime of the magnetization response. The second-harmonic magneto-optic Kerr effect is used to measure the magnetic response at a localized spot on the sample. The measured response is adequately modeled with the Landau-Lifshitz-Gilbert differential equation. We explain the observed behavior in terms of destructive interference. [S0003-6951(00)02915-6]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Kabos, P (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 10 TC 47 Z9 47 U1 0 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 APR 10 PY 2000 VL 76 IS 15 BP 2113 EP 2115 DI 10.1063/1.126280 PG 3 WC Physics, Applied SC Physics GA 301ER UT WOS:000086296200049 ER PT J AU O'Neal, CL Crouch, DJ Fatah, AA AF O'Neal, CL Crouch, DJ Fatah, AA TI Validation of twelve chemical spot tests for the detection of drugs of abuse SO FORENSIC SCIENCE INTERNATIONAL LA English DT Article DE chemical spot test; color test; drug detection AB Validation procedures are described for 12 chemical spot tests including cobalt thiocyanate, Dille-Koppanyi, Duquenois-Levine, Mandelin, Marquis, nitric acid, para- dimethylaminobenzaldehyde, ferric chloride, Froehde, Mecke, Zwikker and Simon's (nitroprusside). The validation procedures include specificity and limit of detection. Depending on the specificity of each color test, between 28 to 45 drugs or chemicals were tested in triplicate with each of the 12 chemical spot tests. For each chemical test, the final colors resulting from positive reactions with known amounts of analytes were compared to two reference color charts. For the identification of unknown drugs, reference colors from the Inter-Society Color Council and the National Bureau of Standards (ISCC-NBS) and Munsell charts are included along with a description of each final color. These chemical spot tests were found to be very sensitive with limits of detection typically 1 to 50 mu g depending on the test and the analyte. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved. C1 Univ Utah, Ctr Human Toxicol, Dept Pharmacol & Toxicol, Salt Lake City, UT 84112 USA. Natl Inst Stand & Technol, Off Law Enforcement Stand, Gaithersburg, MD 20899 USA. RP Crouch, DJ (reprint author), Univ Utah, Ctr Human Toxicol, Dept Pharmacol & Toxicol, 20 S 2030 E,Room 490, Salt Lake City, UT 84112 USA. NR 6 TC 35 Z9 35 U1 6 U2 43 PU ELSEVIER SCI IRELAND LTD PI CLARE PA CUSTOMER RELATIONS MANAGER, BAY 15, SHANNON INDUSTRIAL ESTATE CO, CLARE, IRELAND SN 0379-0738 J9 FORENSIC SCI INT JI Forensic Sci.Int. PD APR 10 PY 2000 VL 109 IS 3 BP 189 EP 201 DI 10.1016/S0379-0738(99)00235-2 PG 13 WC Medicine, Legal SC Legal Medicine GA 302FK UT WOS:000086354900003 PM 10725655 ER PT J AU Neal, SL Mackie, RL Larsen, JC Schultz, A AF Neal, SL Mackie, RL Larsen, JC Schultz, A TI Variations in the electrical conductivity of the upper mantle beneath North America and the Pacific Ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID LONG PERIOD MAGNETOTELLURICS; ELECTROMAGNETIC INDUCTION; INVERSE PROBLEM; MID-MANTLE; HEAT-FLOW; EARTH; CONTINENTS; HETEROGENEITY; HYDROGEN; OLIVINE AB Variations in the electrical conductivity of the mantle beneath Carty Lake in the Canadian Shield, Tucson in the southwest United States, and Honolulu and Midway in the north central Pacific were determined through the inversion of long-period magnetotelluric and geomagnetic depth sounding data. Inversion of computed response functions is carried out using a minimum structure, regularized approach. The upper mantle beneath Carty Lake is approximately an order of magnitude more resistive than the upper mantle beneath Tucson and nearly 1.5 orders of magnitude more resistive than Honolulu and Midway Island. Inversions were also carried out where the minimum structure constraint was removed at known upper mantle discontinuities. These models show a jump in conductivity of similar to 1.5 orders of magnitude across the 660 km discontinuity, a result that is consistent with laboratory experiments on realistic mantle assemblages. Mantle conductivity profiles at Carty Lake are significantly more resistive than those at Tucson, Honolulu, and Midway to depths of similar to 300-400 km. These observations likely reflect differing thermal states, the presence (or absence) of partial melt and volatiles, and may also be related to chemical differences between depleted and undepleted upper mantle. The observed conductivity variations may be interpreted as lateral variations in temperature, partial melt, and/or dissolved hydrogen in olivine. C1 Chevron USA, New Orleans, LA 70112 USA. Pacific Marine Environm Lab, Seattle, WA 98115 USA. GSY USA Inc, San Francisco, CA 94114 USA. Univ Cambridge, Dept Earth Sci, Inst Theoret Geophys, Cambridge CB2 3EQ, England. RP Neal, SL (reprint author), Chevron USA, 935 Gravier St, New Orleans, LA 70112 USA. EM snea@chevron.com; randy@gsy-usa.com; larsen@pmcl.noaa.gov; adam@itg.cam.ac.uk RI Schultz, Adam/K-7394-2012 NR 56 TC 38 Z9 39 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD APR 10 PY 2000 VL 105 IS B4 BP 8229 EP 8242 DI 10.1029/1999JB900447 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 303RK UT WOS:000086437500025 ER PT J AU Chaumet, PC Rahmani, A AF Chaumet, PC Rahmani, A TI Comment on "physical picture for light emission in scanning tunneling microscopy" SO PHYSICAL REVIEW LETTERS LA English DT Article ID QUANTUM ELECTRODYNAMICS; FINITE GEOMETRIES; PHOTON-EMISSION; FIELD; DIELECTRICS; CONDUCTORS C1 CSIC, ICMM, E-28049 Madrid, Spain. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Chaumet, PC (reprint author), CSIC, ICMM, Plaza Murillo 2, E-28049 Madrid, Spain. RI Rahmani, Adel/G-6406-2011; patrick, Chaumet/B-6918-2013 NR 13 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 APR 10 PY 2000 VL 84 IS 15 BP 3498 EP 3498 DI 10.1103/PhysRevLett.84.3498 PG 1 WC Physics, Multidisciplinary SC Physics GA 303DA UT WOS:000086404500071 ER PT J AU Fraser, GT Xu, LH Suenram, RD Lugez, CL AF Fraser, GT Xu, LH Suenram, RD Lugez, CL TI Rotational spectra of four of the five conformers of 1-pentene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SEEDED SUPERSONIC JETS; MICROWAVE SPECTROSCOPY; N-ALKANES; ELECTRON-DIFFRACTION; MOLECULAR MECHANICS; GAS-PHASE; SPECTROMETER; EQUILIBRIUM; RELAXATION; BARRIERS AB The rotational spectra of four of the five expected conformers of 1-pentene, together with their monosubstituted C-13 isotopic forms, have been measured in a molecular beam using a pulsed-nozzle Fourier-transform microwave spectrometer. One of the conformers has C-s point-group symmetry while the other three conformers have C-1 point-group symmetry. The measurements are compared to results from molecular modeling calculations using the MM3 molecular-mechanics force field of Allinger and to ab initio electronic structure calculations (MP2/6-31G*, MP2/6-311G*, MP4/6-31G*, MP4/6-311G*). Both types of calculations suggest the existence of five distinct conformers of 1-pentene, four of C-1 symmetry and one of C-s symmetry. Both the MM3 and ab initio rotational constants deviate from the measured values by less than or equal to 5%. The relatively high barriers between the four conformers limit the conformational cooling in the expansion, allowing all four conformers to be observed at the < 2 K rotational temperature of the molecular beam. Efforts to identify the fifth conformer were unsuccessful, presumably due to its reduced intensity, which makes it difficult to identify its spectral pattern from among the plethora of weak unassigned lines due to impurities, complexes, and possible vibrationally excited conformers. The fifth conformer is predicted to have the highest energy of the five conformers of 1-pentene, as well as a low-energy barrier (109 cm(-1) at MP2/6-311G* level) for conformational isomerization. (C) 2000 American Institute of Physics. [S0021-9606(00)00514-6]. C1 NIST, Opt Tech Div, Gaithersburg, MD 20899 USA. Univ New Brunswick, Dept Phys Sci, St John, NB, Canada. RP Fraser, GT (reprint author), NIST, Opt Tech Div, Gaithersburg, MD 20899 USA. RI Xu, Li-Hong/J-5095-2015 NR 31 TC 26 Z9 26 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 APR 8 PY 2000 VL 112 IS 14 BP 6209 EP 6217 DI 10.1063/1.481220 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 300AX UT WOS:000086231600013 ER PT J AU Louis, F Gonzalez, CA Huie, RE Kurylo, MJ AF Louis, F Gonzalez, CA Huie, RE Kurylo, MJ TI An ab initio study of the kinetics of the reactions of halomethanes with the hydroxyl radical. 1. CH2Br2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-STATE-THEORY; QUADRATIC CONFIGURATION-INTERACTION; BOND-DISSOCIATION ENERGIES; COUPLED-CLUSTER SINGLES; RATE COEFFICIENTS; THERMODYNAMIC PROPERTIES; HYDROGEN ABSTRACTION; SUBSTITUTED METHANES; BROMOMETHYL RADICALS; PERTURBATION-THEORY AB Ab initio calculations were carried out with Moller-Plesset second- and fourth-order perturbation theory (MP2 and MP4), and the coupled cluster method, CCSD(T), on the H atom abstraction reaction from dibromomethane by hydroxyl radical attack. Geometry optimization and vibrational frequency calculations at the MP2 level were performed on reactants, products, and the transition state using the 6-311G(d,p) and 6-311G(2d,2p) basis sets. The geometry parameters optimized at: the MP2/6-311G(2d,2p) level of theory were used in single-point energy calculations with increasing basis set sizes, from 6-311G(2d,2p) to 6-311++G-(3df,3pd) at both the MP2 and MP4(SDTQ) levels of theory. Canonical transition-state theory was used to predict the rate constants as a function of the temperature (250-400 K). It was found that the kinetic parameters obtained in this work with the spin-projected method PMP4(SDTQ)/6-311++G(3df,3pd)//MP2/6-311G(2d,-2p) are in reasonable agreement with the experimental values. The prospect of using relatively low level ab initio electronic structure calculations aimed at the implementation of inexpensive semiquantitative "screening tools" that could aid scientists in predicting the kinetics of similar processes is also discussed. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Louis, F (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Kurylo, Michael/H-2201-2012; OI Louis, Florent/0000-0002-9533-557X NR 62 TC 23 Z9 23 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD APR 6 PY 2000 VL 104 IS 13 BP 2931 EP 2938 DI 10.1021/jp991022e PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 302DA UT WOS:000086349000011 ER PT J AU Gonzalez, C Lim, EC AF Gonzalez, C Lim, EC TI Quantum chemistry study of the van der Waals dimers of benzene, naphthalene, and anthracene: Crossed (D-2d) and parallel-displaced (C-2h) dimers of very similar energies in the linear polyacenes SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MOLECULAR MECHANICS; GENETIC ALGORITHM; CLUSTERS; MINIMIZATION; SPECTROSCOPY; SPECTRA; SURFACE; ISOMERS; FIELD; WATER AB A quantum chemistry study of the ground-state structures and binding energies of the van der Waals dimers of benzene, naphthalene, and anthracene has been made at the MP2/6-31G and MP2/6-31+G levels of theory. For naphthalene and anthracene, the calculations yield two low energy dimers of very similar energies: D-2d (crossed) and C-2h (parallel-displaced). Conformers, analogous to the T-shaped dimer of benzene, are less stable than the crossed and the parallel-displaced dimers. BSSE-corrected MP2/6-31+G//MP2/6-31G binding energies of the crossed and parallel-displaced dimers are,respectively, 15.77 and 15.65 kJ/mol for naphthalene and 36.40 and 31.84 kJ/mol for anthracene. The fully optimized MP2/6-31G structures of the parallel-displaced dimer of naphthalene has a horizontal displacement of 1.5 Angstrom along the short axes of the monomers and a vertical displacement of 3.5 Angstrom. The corresponding horizontal and vertical separations for the parallel-displaced (PD) dimer of anthracene are 1.1 and 3.6 Angstrom, respectively. For the crossed dimers, the vertical separation of the aromatic rings is 3.6 Angstrom for naphthalene and 3.3 Angstrom for anthracene. The greater binding energy and the shorter horizontal displacement of the anthracene PD dimer relative to the naphthalene PD dimer are consistent with the stronger dispersion interactions expected of a larger dimer. The greater stability and smaller vertical separation of the crossed dimer of anthracene relative to that of naphthalene can also be attributed to the disparity in the dispersion interactions. C1 Univ Akron, Dept Chem, Goodyear Chair Chem, Akron, OH 44325 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Lim, EC (reprint author), Univ Akron, Dept Chem, Goodyear Chair Chem, Akron, OH 44325 USA. NR 41 TC 106 Z9 106 U1 1 U2 17 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 APR 6 PY 2000 VL 104 IS 13 BP 2953 EP 2957 DI 10.1021/jp993642l PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 302DA UT WOS:000086349000013 ER PT J AU Roszak, S Krauss, M Alekseyev, AB Liebermann, HP Buenker, RJ AF Roszak, S Krauss, M Alekseyev, AB Liebermann, HP Buenker, RJ TI Spin-orbit configuration interaction calculation of the potential energy curves of iodine oxide SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ABSORPTION CROSS-SECTIONS; RELATIVISTIC EFFECTIVE POTENTIALS; ELECTRON RESONANCE SPECTRA; PHOTOELECTRON-SPECTROSCOPY; SELF-REACTION; IO RADICALS; KINETICS; BRO; PHOTOLYSIS; CI AB An ab initio configuration interaction (CI) study including spin-orbit coupling is carried out for the ground and excited states of the IO radical by employing relativistic effective core potentials. Thee computed spectroscopic constants are in good agreement with available experimental data, with some tendency to underestimate the strength of bonding. The first excited state, a(4)Sigma(-), which has not yet been observed experimentally, is predicted to be bound by 30.1 kJ/mol and to have a significantly larger equilibrium distance than the ground state. It is split by spin-orbit interaction into 1/2 and 3/2 components, with the 1/2 component being the lower one with a calculated spin-orbit splitting of 210 cm(-1). The most interesting state in the low-energy IO;spectrum, A(1)(2)Pi(3/2), is shown to be predissociated due to interaction with a number of repulsive electronic states. Predissociation of the A(1), v' = 0, I vibrational levels is attributed to a fairly weak spinorbit coupling with the (2)Delta(3/2) state, while rotationally dependent predissociation of the v' = 2 level is explained by the coupling with the 1/2(III) state having mainly (2)Sigma(-) character. Strong predissociation of the v' greater than or equal to 4 levels is attributed to interaction with the higher-lying Omega = 3/2 states, with predominantly (4)Sigma(+) and (4)Delta origin. C1 Wroclaw Univ Technol, Inst Phys & Theoret Chem, PL-50370 Wroclaw, Poland. Berg Univ Gesamthsch Wuppertal, Fachbereich Theoret Chem 9, D-42097 Wuppertal, Germany. NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Alekseyev, AB (reprint author), Berg Univ Gesamthsch Wuppertal, Fachbereich Theoret Chem 9, Gaussstr 20, D-42097 Wuppertal, Germany. NR 47 TC 26 Z9 26 U1 1 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 APR 6 PY 2000 VL 104 IS 13 BP 2999 EP 3003 DI 10.1021/jp994002l PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 302DA UT WOS:000086349000021 ER PT J AU Livezey, RE AF Livezey, RE TI Statistical analysis in climate research SO NATURE LA English DT Book Review C1 NOAA, Natl Weather Serv, Div Climate Serv, Meteorol Off, Silver Spring, MD 20910 USA. RP Livezey, RE (reprint author), NOAA, Natl Weather Serv, Div Climate Serv, Meteorol Off, Rm 13228,1325 East West Highway, Silver Spring, MD 20910 USA. NR 1 TC 0 Z9 0 U1 1 U2 13 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 6 PY 2000 VL 404 IS 6778 BP 544 EP 544 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 303BC UT WOS:000086400100024 ER PT J AU DiTullio, GR Grebmeier, JM Arrigo, KR Lizotte, MP Robinson, DH Leventer, A Barry, JB VanWoert, ML Dunbar, RB AF DiTullio, GR Grebmeier, JM Arrigo, KR Lizotte, MP Robinson, DH Leventer, A Barry, JB VanWoert, ML Dunbar, RB TI Rapid and early export of Phaeocystis antarctica blooms in the Ross Sea, Antarctica SO NATURE LA English DT Article ID PHYTOPLANKTON; CARBON; DIMETHYLSULFIDE; POUCHETII; PRYMNESIOPHYCEAE; POLYNYA; OCEAN; CYCLE AB The Southern Ocean is very important for the potential sequestration of carbon dioxide in the oceans(1) and is expected to be vulnerable to changes in carbon export forced by anthropogenic climate warming(2). Annual phytoplankton blooms in seasonal ice zones are highly productive and are thought to contribute significantly to pCO(2) drawdown in the Southern Ocean. Diatoms are assumed to be the most important phytoplankton class with respect to export production in the Southern Ocean; however, the colonial prymnesiophyte Phaeocystis antarctica regularly forms huge blooms in seasonal ice zones and coastal Antarctic waters(3). There is little evidence regarding the fate of carbon produced by P. antarctica in the Southern Ocean, although remineralization in the upper water column has been proposed to be the main pathway in polar waters(4,5). Here we present evidence for early and rapid carbon export from P. antarctica blooms to deep water and sediments in the Ross Sea. Carbon sequestration from P. antarctica blooms may influence the carbon cycle in the Southern Ocean, especially if projected climatic changes lead to an alteration in the structure of the phytoplankton community(6,7). C1 Univ Charleston, Grice Marine Lab, Charleston, SC 29412 USA. Univ Tennessee, Knoxville, TN 37996 USA. Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. Univ Wisconsin, Dept Biol & Microbiol, Oshkosh, WI 54901 USA. San Francisco State Univ, Romberg Tiburon Ctr, Tiburon, CA 94920 USA. Colgate Univ, Dept Geol, Hamilton, NY 13346 USA. Monterey Bay Aquarium Res Inst, Moss Landing, CA 95039 USA. NOAA, NESDIS, Off Res & Applicat, Camp Springs, MD 20746 USA. Natl Ice Ctr, Washington, DC 20395 USA. Stanford Univ, Stanford, CA 94305 USA. RP DiTullio, GR (reprint author), Univ Charleston, Grice Marine Lab, 205 Ft Johnson, Charleston, SC 29412 USA. EM ditullioj@cofc.edu RI Grebmeier, Jacqueline/L-9805-2013 OI Grebmeier, Jacqueline/0000-0001-7624-3568 NR 28 TC 165 Z9 170 U1 2 U2 33 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD APR 6 PY 2000 VL 404 IS 6778 BP 595 EP 598 DI 10.1038/35007061 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 303BC UT WOS:000086400100051 PM 10766240 ER PT J AU Williams, AB Vargas, R AF Williams, AB Vargas, R TI A new species of mud shrimp, Upogebia cortesi, from Pacific Costa Rica (Decapoda : Thalassinidea : Upogebiidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Upogebia cortesi, a new species of mud shrimp from the Pacific side of Costa Rica is described and illustrated. The type series was dredged parallel to shore in water of 30-40 m depth. The species shares lack of a strong proximal mesioventral spine on the merus of the second pereopod with several members of the genus from the western hemisphere; moreover, the species stands alone in having spineless articles on pereopods 1-5 except for fingers of the chelae. The rostrum has no ventral spines. Similarities between this and related species are emphasized in a partial abridgment of the key to upogebiid species in the eastern Pacific. C1 Smithsonian Inst, Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. Univ Costa Rica, Escuela Biol, Museu Zool, San Jose 2060, Costa Rica. RP Williams, AB (reprint author), Smithsonian Inst, Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. NR 5 TC 0 Z9 3 U1 1 U2 1 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD APR 6 PY 2000 VL 113 IS 1 BP 13 EP 16 PG 4 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 303MK UT WOS:000086425500002 ER PT J AU Kielhorn, L Colby, RH Han, CC AF Kielhorn, L Colby, RH Han, CC TI Relaxation behavior of polymer blends after the cessation of shear SO MACROMOLECULES LA English DT Article ID INDUCED HOMOGENIZATION; SEMIDILUTE SOLUTION; RHEOLOGICAL RESPONSE; LIGHT-SCATTERING; FLOW; MIXTURES; PHASE; FLUIDS; DEPENDENCE; MICROSCOPY AB We investigated the relaxation of a binary polybutadiene/polyisoprene blend after the cessation of steady-state shear using both in situ optical microscopy (OM) and light scattering (LS). Through fast Fourier transforms of the micrographs, we were able to directly relate our LS patterns with the real space morphology. In the steady state we observed ellipsoidal domains and strings. Upon the cessation of shear, these morphologies relaxed to the equilibrium morphology via a variety of mechanisms. After low shear rates were applied, coalescence between domains of random spatial distribution occurred. If the shear rate previously applied was sufficiently high, the strings were found to break up into small droplets forming necklace-like structures. The nonrandom spatial distribution created by shearing resulted in a long-lasting anisotropy at rest. If the previously applied shear rate was further increased, thermodynamic effects became important and anisotropies relaxed very fast: as a consequence. A spinodal pattern in both real space and in the LS patterns was found to occur during the relaxation process. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. RP Han, CC (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 39 TC 30 Z9 32 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD APR 4 PY 2000 VL 33 IS 7 BP 2486 EP 2496 DI 10.1021/ma9914265 PG 11 WC Polymer Science SC Polymer Science GA 302AV UT WOS:000086343500030 ER PT J AU Raghavan, D Gu, X Nguyen, T VanLandingham, M Karim, A AF Raghavan, D Gu, X Nguyen, T VanLandingham, M Karim, A TI Mapping polymer heterogeneity using atomic force microscopy phase imaging and nanoscale indentation SO MACROMOLECULES LA English DT Article ID TAPPING-MODE AFM; BOUND FUNCTIONAL-GROUPS; ORGANIC COATINGS; BLOCK-COPOLYMERS; BLEND FILMS; SURFACE; RESOLUTION; SUBSTRATE; SPECTROSCOPY; ELECTROLYTE AB Polymer coatings often contain degradation-susceptible regions, and corrosion of the metallic substrate can occur directly underneath these regions. In this paper, the microstructure of model coating materials is investigated using atomic force microscopy (AFM). Specifically, AFM is used to study heterogeneity in thin film blends of polystyrene (PS) and polybutadiene (PB) as a function of annealing time at 80 degrees C. PS/PB blend films with thicknesses of approximately 250 nm are prepared by spin casting from solutions onto silicon substrates. Both topographic and phase imaging in tapping mode AFM are performed on these films under ambient conditions and at different force levels using a silicon tip. For certain force levels, phase imaging provides good contrast between the phase-separated PS and PB regions, primarily because of the large compliance difference between the two materials. This contrast decreases with increasing annealing time because thermal oxidation causes cross-linking in PB, and thus, the compliance of the PB region increases toward that of PS. Nanoscale indentation measurements are then made on the observed phase-separated regions to identify these regions as PS- and PB-rich and to better understand the influence of relative surface stiffness on the phase images. Cast and free-standing films of pure PS and pure PB are also studied as a function of annealing time using AFM, contact angle measurements, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). Results from studies of the individual PS and PB films are related to the AFM results for the blend films. The use of phase imaging for cure monitoring of polymers and for studies of chemically heterogeneous polymer systems is also discussed. C1 Howard Univ, Dept Chem, Polymer Sci Div, Washington, DC 20059 USA. Natl Inst Stand & Technol, Bldg & Fire Res Lab, Bldg Mat Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Div Polymer, Gaithersburg, MD 20899 USA. RP Howard Univ, Dept Chem, Polymer Sci Div, Washington, DC 20059 USA. EM draghavan@howard.edu NR 70 TC 171 Z9 175 U1 2 U2 60 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 EI 1520-5835 J9 MACROMOLECULES JI Macromolecules PD APR 4 PY 2000 VL 33 IS 7 BP 2573 EP 2583 DI 10.1021/ma991206r PG 11 WC Polymer Science SC Polymer Science GA 302AV UT WOS:000086343500042 ER PT J AU Hamann, HF Gallagher, A Nesbitt, DJ AF Hamann, HF Gallagher, A Nesbitt, DJ TI Near-field fluorescence imaging by localized field enhancement near a sharp probe tip SO APPLIED PHYSICS LETTERS LA English DT Article ID OPTICAL MICROSCOPY; SPATIAL-RESOLUTION AB This work describes near-field investigations of luminescent nanosamples based on monitoring fluorescence due to the enhanced field around a laser-illuminated probe tip. These fluorescence effects are investigated as a function of probe-sample separation, which identify a strong, spatially localized (approximate to 7 nm) enhancement of the incident laser field in the vicinity of the probe tip. From a model fit to the fluorescence data, the localized enhancement of the electric field is estimated to be > tenfold, which predicts a significant increase in localized excitation intensity (> 100-fold) for fluorescence imaging of molecular size samples. (C) 2000 American Institute of Physics. [S0003-6951(00)04014-6]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Hamann, HF (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 13 TC 79 Z9 79 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 APR 3 PY 2000 VL 76 IS 14 BP 1953 EP 1955 DI 10.1063/1.126223 PG 3 WC Physics, Applied SC Physics GA 298JC UT WOS:000086134700054 ER PT J AU Storebakken, T Shearer, KD Baeverfjord, G Nielsen, BG Asgard, T Scott, T De Laporte, A AF Storebakken, T Shearer, KD Baeverfjord, G Nielsen, BG Asgard, T Scott, T De Laporte, A TI Digestibility of macronutrients, energy and amino acids, absorption of elements and absence of intestinal enteritis in Atlantic salmon, Salmo salar, fed diets with wheat gluten SO AQUACULTURE LA English DT Article DE wheat gluten-soybean meal-LT fish meal; digestibility-fat-protein-energy; absorption-amino acid-elements-minerals-phosphorus; soybean-induced enteritis; Atlantic salmon - Salmo salar ID TROUT ONCORHYNCHUS-MYKISS; RAINBOW-TROUT; DISTAL INTESTINE; SOYBEAN-MEAL; FISH-MEAL; GASTROINTESTINAL-TRACT; PHYTIC ACID; FEED-INTAKE; PROTEIN; GROWTH AB Apparent digestibility coefficients (ADCs) of macronutrients and energy, and apparent absorption coefficients (AACs) of amino acids and elements were assessed in an experiment with 0.9 kg Atlantic salmon reared in saltwater tanks. Duplicate groups of fish were fed five diets, where 0, 6.25, 12.5, 25 and 50% of crude protein (CP) from fish meal (FM) was replaced with CP from wheat gluten (WG). In Experiment 2, triplicate groups of 0.9 kg salmon were fed a FM diet, a diet with 15% of CP from FM replaced with extracted, toasted soybean meal (SBM), and a diet with 35% of CP from WG, for 18 weeks. Experiment 2 was designed to determine whether WG caused pathological changes in the intestinal epithelium, and if a diet with 35% of CP from WG could support rapid growth. There was a trend toward increased ADC of fat and energy in the diets with WG, and the diet with 25% WG was ranked significantly higher than the FM control. The ADC of CP and AACs of all amino acids except alanine and lysine increased significantly with increasing proportion of dietary protein from WG, and the results indicate that absorption of individual amino acids from WG was between 94% and 100%, WG is low in lysine, but the results indicate that the requirement for lysine was nearly met and the requirement for other essential amino acids was met even with the highest WG inclusion level, due to high dietary protein concentration and the supplementary amino acid profile of FM. There was no reduced absorption of Ca, P or Mg in the salmon fed diets with WG. The absorption of Zn was higher in all the diets with WG than in the FM diet. The fish doubled their weight during Experiment 2, and there were no significant differences in growth among dietary treatments in salmon fed the WG, FM or SBM diets. No indication of intestinal pathology was seen in the salmon fed the FM or WG diets, while 60% of the examined fish fed SBM had SBM-induced changes in the mucosa of the posterior intestine. (C) 2000 Elsevier Science B.V. All rights reserved. C1 AKVAFORSK, Inst Aquaculture Res AS, N-6600 Sunndalsora, Norway. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. BioMar, N-8430 Myre, Norway. Amylum Grp, Amycor, B-9300 Aalst, Belgium. RP Storebakken, T (reprint author), AKVAFORSK, Inst Aquaculture Res AS, N-6600 Sunndalsora, Norway. RI storebakken, trond/E-8050-2011 OI storebakken, trond/0000-0002-4525-2098 NR 53 TC 87 Z9 90 U1 2 U2 28 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD APR 3 PY 2000 VL 184 IS 1-2 BP 115 EP 132 DI 10.1016/S0044-8486(99)00316-6 PG 18 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 294JK UT WOS:000085908000009 ER PT J AU Assel, RA Janowiak, JE Boyce, D O'Connors, C Quinn, FH Norton, DC AF Assel, RA Janowiak, JE Boyce, D O'Connors, C Quinn, FH Norton, DC TI Laurentian Great Lakes ice and weather conditions for the 1998 El Nino winter SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID COVER; SEVERITY; TELECONNECTIONS; MICHIGAN AB Winter 1997/98 occurred during one of the strongest warm El Nino events, and the Great Lakes experienced one of the least extensive ice covers of this century. Seasonal maximum ice cover for the combined area of the Great Lakes was the lowest on record (15%) relative to winters since 1963, a distinction formerly held by winter 1982/83 (25%), which was also an exceptionally strong El Nino winter. Maximum ice covers set new lows in winter 1997/98 for Lakes Erie (5%), Ontario (6%), and Superior (11%), tied the all-time low for Lake Huron (29%), and came close to tying the all-time low on Lake Michigan (15%; all-time low is 13%). Here the authors compare seasonal progression of lake-averaged ice cover for winter 1982/83, winter 1997/98, and a 20-winter normal (1960-79) derived from the NOAA Great Lakes Ice Atlas and discuss the 1997/98 ice cover in detail. Winter air temperatures in the Great Lakes were at or near record high levels, storms were displaced farther to the south over eastern North America, and precipitation was below average in the northern portion of the Great Lakes region. The Northern Hemispheric synoptic flow patterns responsible for this winter weather, the Great Lakes winter severity over the past two centuries, and impacts of this mild winter are briefly discussed. C1 NOAA, Great Lakes Environm Res Lab, ERL, Ann Arbor, MI 48105 USA. NOAA, CAC, NWS, NMC, Camp Springs, MD USA. NOAA, NWS, Cleveland, OH USA. NOAA, Natl Environm Satellite Data & Informat Serv, NIC, Washington, DC 20233 USA. RP Assel, RA (reprint author), NOAA, Great Lakes Environm Res Lab, ERL, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. NR 33 TC 18 Z9 19 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2000 VL 81 IS 4 BP 703 EP 717 DI 10.1175/1520-0477(2000)081<0703:LGLIAW>2.3.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400003 ER PT J AU Nuss, WA Bane, JM Thompson, WT Holt, T Dorman, CE Ralph, FM Rotunno, R Klemp, JB Skamarock, WC Samelson, RM Rogerson, AM Reason, C Jackson, P AF Nuss, WA Bane, JM Thompson, WT Holt, T Dorman, CE Ralph, FM Rotunno, R Klemp, JB Skamarock, WC Samelson, RM Rogerson, AM Reason, C Jackson, P TI Coastally trapped wind reversals: Progress toward understanding SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID STATES WEST-COAST; WARM-SEASON; SYNOPTIC EVOLUTION; LOWER ATMOSPHERE; KELVIN WAVES; MARINE-LAYER; NORTHERN CALIFORNIA; PACIFIC-NORTHWEST; DISTURBANCES; PROPAGATION AB Coastally trapped wind reversals along the U.S. west coast, which are often accompanied by a northward surge of fog or stratus, are an important warm-season forecast problem due to their impact on coastal maritime activities and airport operations. Previous studies identified several possible dynamic mechanisms that could be responsible for producing these events, yet observational and modeling limitations at the time left these competing interpretations open for debate. In an effort to improve our physical understanding, and ultimately the prediction, of these events, the Office of Naval Research sponsored an Accelerated Research Initiative in Coastal Meteorology during the years 1993-98 to study these and other related coastal meteorological phenomena. This effort included two field programs to study coastally trapped disturbances as well as numerous modeling studies to explore key dynamic mechanisms. This paper describes the various efforts that occurred under this program to provide an advancement in our understanding of these disturbances. While not all issues have been solved, the synoptic and mesoscale aspects of these events are considerably better understood. C1 USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. USN, Res Lab, Monterey, CA 93943 USA. Univ N Carolina, Marine Sci Program, Chapel Hill, NC USA. Univ Calif San Diego, Scripps Inst Oceanog, Coastal Studies Program, La Jolla, CA 92093 USA. NOAA, Environm Res Lab, Environm Technol Lab, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Univ Melbourne, Sch Earth Sci, Parkville, Vic 3052, Australia. Univ No British Columbia, Environm Studies Program, Prince George, BC V2L 5P2, Canada. RP Nuss, WA (reprint author), USN, Postgrad Sch, Dept Meteorol, 589 Dyer Rd,Room 254, Monterey, CA 93943 USA. NR 50 TC 31 Z9 31 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2000 VL 81 IS 4 BP 719 EP 743 DI 10.1175/1520-0477(2000)081<0719:CTWRPT>2.3.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400004 ER PT J AU Hufford, GL Salinas, LJ Simpson, JJ Barske, EG Pieri, DC AF Hufford, GL Salinas, LJ Simpson, JJ Barske, EG Pieri, DC TI Operational implications of airborne volcanic ash SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID ERUPTION; REDOUBT AB Volcanic ash clouds pose a real threat to aircraft safety. The ash is abrasive and capable of causing serious damage to aircraft engines, control surfaces, windshields, and landing lights. In addition, ash can clog the pitot-static systems, which determine wind speed and altitude, and damage sensors used to fly the aircraft. To ensure aviation safety, a warning system should be capable of a 5-min response time once an eruption has been detected. Pilots are the last link in the chain of safety actions to avoid or mitigate encounters with volcanic ash. For the pilots to be effective, the warning and safety system must meet their needs. The ability to issue accurate and timely warnings, advisories, and forecasts re quires a rapid means to detect and continually track the ash cloud and smooth coordination between many agencies. The current operational ash detection technique uses satellite remote sensing. Potential problems with this technique and the potential impact of these problems on aircraft safety are discussed. C1 Natl Weather Serv, Anchorage, AK 99513 USA. United Airlines, World Headquarters, Chicago, IL USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Natl Weather Serv, Alaska Aviat Weather Unit, Anchorage, AK USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Hufford, GL (reprint author), Natl Weather Serv, 222 W 7th Ave,23, Anchorage, AK 99513 USA. NR 25 TC 18 Z9 18 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2000 VL 81 IS 4 BP 745 EP 755 DI 10.1175/1520-0477(2000)081<0745:OIOAVA>2.3.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400005 ER PT J AU LeMone, MA Grossman, RL Coulter, RL Wesley, ML Klazura, GE Poulos, GS Blumen, W Lundquist, JK Cuenca, RH Kelly, SF Brandes, EA Oncley, SP McMillen, RT Hicks, BB AF LeMone, MA Grossman, RL Coulter, RL Wesley, ML Klazura, GE Poulos, GS Blumen, W Lundquist, JK Cuenca, RH Kelly, SF Brandes, EA Oncley, SP McMillen, RT Hicks, BB TI Land-atmosphere interaction research, early results, and opportunities in the Walnut River Watershed in southeast Kansas: CASES and ABLE SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CONVECTIVE BOUNDARY-LAYER; PROGRAM; PROJECT; WSR-88D; TURBULENCE; FACILITY; MOISTURE; SUPPORT; WEATHER; BOREAS AB This paper describes the development of the Cooperative Atmosphere Surface Exchange Study (CASES), its synergism with the development of the Atmosphere Boundary Layer Experiments (ABLE) and related efforts, CASES field programs, some early results, and future plans and opportunities. CASES is a grassroots multidisciplinary effort to study the interaction of the lower atmosphere with the land surface, the subsurface. and vegetation over timescales ranging from nearly instantaneous to years. CASES scientists developed a consensus that observations should be taken in a watershed between 50 and 100 km across; practical considerations led to an approach combining long-term data collection with episodic intensive field campaigns addressing specific objectives that should always include improvement of the design of the long-term instrumentation. In 1997, long-term measurements were initiated in the Walnut River Watershed east of Wichita, Kansas. Argonne National Laboratory started setting up the ABLE array. The first of the long-term hydrological enhancements was installed starting in May by the Hydrologic Science Team of Oregon State University. CASES-97, the first episodic field effort, was held during April-June to study the role of surface processes in the diurnal variation of the boundary layer, to test radar precipitation algorithms, and to define relevant scaling for precipitation and soil properties. The second episodic experiment, CASES-99, was conducted during October 1999, and focused on the stable boundary layer. Enhancements to both the atmospheric and hydrological arrays continue. The data from and information regarding both the long-term and episodic experiments are available on the World Wide Web. Scientists are invited to use the data and to consider the Walnut River Watershed for future field programs. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Colorado, Program Atmospher & Ocean Studies, Boulder, CO 80309 USA. Argonne Natl Lab, Div Environm Res, Argonne, IL 60439 USA. Colorado Res Associates, Boulder, CO USA. Oregon State Univ, Dept Engn, Corvallis, OR 97331 USA. NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN USA. NOAA, Atmospher Res Lab, Silver Spring, MD USA. RP LeMone, MA (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. OI LUNDQUIST, JULIE/0000-0001-5490-2702 NR 62 TC 71 Z9 72 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2000 VL 81 IS 4 BP 757 EP 779 DI 10.1175/1520-0477(2000)081<0757:LIRERA>2.3.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400006 ER PT J AU Pawson, S Kodera, K Hamilton, K Shepherd, TG Beagley, SR Boville, BA Farrara, JD Fairlie, TDA Kitoh, A Lahoz, WA Langematz, U Manzini, E Rind, DH Scaife, AA Shibata, K Simon, P Swinbank, R Takacs, L Wilson, RJ Al-Saadi, JA Amodei, M Chiba, M Coy, L de Grandpre, J Eckman, RS Fiorino, M Grose, WL Koide, H Koshyk, JN Li, D Lerner, J Mahlman, JD McFarlane, NA Mechoso, CR Molod, A O'Neill, A Pierce, RB Randel, WJ Rood, RB Wu, F AF Pawson, S Kodera, K Hamilton, K Shepherd, TG Beagley, SR Boville, BA Farrara, JD Fairlie, TDA Kitoh, A Lahoz, WA Langematz, U Manzini, E Rind, DH Scaife, AA Shibata, K Simon, P Swinbank, R Takacs, L Wilson, RJ Al-Saadi, JA Amodei, M Chiba, M Coy, L de Grandpre, J Eckman, RS Fiorino, M Grose, WL Koide, H Koshyk, JN Li, D Lerner, J Mahlman, JD McFarlane, NA Mechoso, CR Molod, A O'Neill, A Pierce, RB Randel, WJ Rood, RB Wu, F TI The GCM-reality intercomparison project for SPARC (GRIPS): Scientific issues and initial results SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID GENERAL-CIRCULATION MODEL; GRAVITY-WAVE DRAG; MIDDLE ATMOSPHERE MODEL; DOPPLER-SPREAD PARAMETERIZATION; STRATOSPHERE-MESOSPHERE GCM; NORTHERN-HEMISPHERE WINTER; ANNUAL CYCLE; INTERANNUAL VARIABILITY; METEOROLOGICAL-OFFICE; NUMERICAL FORECASTS AB To investigate the effects of the middle atmosphere on climate, the World Climate Research Programme is supporting the project "Stratospheric Processes and their Role in Climate" (SPARC). A central theme of SPARC, to examine model simulations of the coupled troposphere-middle atmosphere system, is being performed through the initiative called GRIPS (GCM-Reality Intercomparison Project for SPARC). In this paper, an overview of the objectives of GRIPS is given. Initial activities include an assessment of the performance of middle atmosphere climate models, and preliminary results from this evaluation are presented here. It is shown that although all 13 models evaluated represent most major features of the mean atmospheric state, there are deficiencies in the magnitude and location of the features, which cannot easily be traced to the formulation (resolution or the parameterizations included) of the models. Most models show a cold bias in all locations, apart from the tropical tropopause region where they can be either too warm or too cold. The strengths and locations of the major jets are often misrepresented in the models. Looking at three-dimensional fields reveals, for some models, more severe deficiencies in the magnitude and positioning of the dominant structures (such as the Aleutian high in the stratosphere), although undersampling might explain some of these differences from observations. All the models have shortcomings in their simulations of the present-day climate, which might limit the accuracy of predictions of the climate response to ozone change and other anomalous forcing. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Data Assimilat Off, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD USA. Free Univ Berlin, D-1000 Berlin, Germany. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. Univ Toronto, Toronto, ON, Canada. York Univ, Toronto, ON M3J 2R7, Canada. NCAR, Boulder, CO USA. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90024 USA. Sci & Technol Corp, Hampton, VA 23666 USA. Univ Reading, Ctr Global Atmospher Modelling, Reading, Berks, England. Max Planck Inst Meteorol, Hamburg, Germany. NASA, Goddard Inst Space Studies, Palisades, NY USA. United Kingdom Meteorol Off, Bracknell, Berks, England. Meteo France, CNRM, Toulouse, France. Gen Sci Corp, Beltsville, MD USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NIESDP, Tsukuba, Ibaraki, Japan. LLNI, PCMDI, Livermore, CA USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. AES, Victoria, BC, Canada. RP Pawson, S (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Data Assimilat Off, Code 910-3,Bldg 33, Greenbelt, MD 20771 USA. EM pawson@dao.gsfc.nasa.gov RI Pierce, Robert Bradley/F-5609-2010; Manzini, Elisa/H-5760-2011; Rood, Richard/C-5611-2008; Fiorino, Michael/N-4150-2014; Pawson, Steven/I-1865-2014; Randel, William/K-3267-2016 OI Pierce, Robert Bradley/0000-0002-2767-1643; Rood, Richard/0000-0002-2310-4262; Fiorino, Michael/0000-0002-2819-8157; Pawson, Steven/0000-0003-0200-717X; Randel, William/0000-0002-5999-7162 NR 62 TC 125 Z9 128 U1 1 U2 16 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2000 VL 81 IS 4 BP 781 EP 796 DI 10.1175/1520-0477(2000)081<0781:TGIPFS>2.3.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400007 ER PT J AU Soden, B Tjemkes, S Schmetz, J Saunders, R Bates, J Ellingson, B Engelen, R Garand, L Jackson, D Jedlovec, G Kleespies, T Randel, D Rayer, P Salathe, E Schwarzkopf, D Scott, N Sohn, B de Souza-Machado, S Strow, L Tobin, D Turner, D van Delst, P Wehr, T AF Soden, B Tjemkes, S Schmetz, J Saunders, R Bates, J Ellingson, B Engelen, R Garand, L Jackson, D Jedlovec, G Kleespies, T Randel, D Rayer, P Salathe, E Schwarzkopf, D Scott, N Sohn, B de Souza-Machado, S Strow, L Tobin, D Turner, D van Delst, P Wehr, T TI An intercomparison of radiation codes for retrieving upper-tropospheric humidity in the 6.3-mu m band: A report from the first GVaP workshop SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID WATER-VAPOR; MU-M; RADIANCES; ABSORPTION; ASSIMILATION; CLIMATOLOGY; CHANNEL; OZONE AB An intercomparison of radiation codes used in retrieving upper-tropospheric humidity (UTH) from observations in the v2 (6.3 mu m) water vapor absorption band was performed. This intercomparison is one part of a coordinated effort within the Global Energy and Water Cycle Experiment Water Vapor Project to assess our ability to monitor the distribution and variations of upper-tropospheric moisture from spaceborne sensors. A total of 23 different codes, ranging from detailed line-by-line (LBL) models, to coarser-resolution narrowband (NB) models, to highly parameterized single-band (SB) models participated in the study. Forward calculations were performed using a carefully selected set of temperature and moisture profiles chosen to be representative of a wide range of atmospheric conditions. The LBL model calculations exhibited the greatest consistency with each other, typically agreeing to within 0.5 K in terms of the equivalent blackbody brightness temperature (T-b). The majority of NE and SE models agreed to within +/-1 K of the LBL models, although a few older models exhibited systematic T-b biases in excess of 2 K. A discussion of the discrepancies between various models, their association with differences in model physics (e.g., continuum absorption), and their implications for UTH retrieval and radiance assimilation is presented. C1 NOAA, GFDL, Princeton, NJ USA. EUMETSAT, Darmstadt, Germany. ECMWF, Reading, Berks, England. NOAA, CDC, Boulder, CO USA. Univ Maryland, College Pk, MD 20742 USA. Colorado State Univ, Ft Collins, CO 80523 USA. AES, Dorval, PQ, Canada. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Washington, DC 20233 USA. CSU, CIRA, Ft Collins, CO USA. Meteorol Off, Bracknell RB12 2SZ, Berks, England. Univ Washington, Seattle, WA 98195 USA. Ecole Polytech, CNRS, LMD, F-91128 Palaiseau, France. Seoul Natl Univ, Seoul, South Korea. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. Univ Wisconsin, Madison, WI USA. RP Soden, B (reprint author), Princeton Univ, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. RI Kleespies, Thomas/F-5598-2010; Jackson, Darren/D-5506-2015; Bates, John/D-1012-2009 OI Jackson, Darren/0000-0001-5211-7866; Bates, John/0000-0002-8124-0406 NR 44 TC 42 Z9 42 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD APR PY 2000 VL 81 IS 4 BP 797 EP 808 DI 10.1175/1520-0477(2000)081<0797:AIORCF>2.3.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300PY UT WOS:000086262400008 ER PT J AU Torrents, JM Mason, TO Garboczi, EJ AF Torrents, JM Mason, TO Garboczi, EJ TI Impedance spectra of fiber-reinforced cement-based composites - A modeling approach SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE electrical properties; Portland cement; composite; fiber reinforcement; impedance ID CARBON-FIBER; ELECTRICAL-RESISTIVITY; SPECTROSCOPY; CONDUCTIVITY; MORTAR AB The impedance response of conductive fiber-reinforced cement-based materials was investigated using model systems physical simulations) consisting of conducting needles in aqueous solutions. Two discrete bulk arcs are observed in the Nyquist plots for fiber-reinforced samples, while only a single bulk are was observed for samples without fibers. This difference is attributable to thin, resistive, and highly capacitive layers (e.g., oxide film or polarization/double layers) which reside on the surfaces of the conducting fibers. These layers fully insulate the fibers at low frequencies (near DC), so that the highly conducting fibers behave as if they were insulating fibers. At intermediate frequencies, these layers short out, so that the fibers act as highly conducting elements in the microstructure. Spreading resistance effects from the ends of the fibers play an important role in the high frequency behavior. Pixel-based computer modeling results are presented to rationalize both DC and high frequency behavior. Experimental and modeling results are used to develop an equivalent circuit model containing a frequency-switchable fiber coating element. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Northwestern Univ, Ctr Adv Cement Based Mat, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NIST, Bldg Mat Div, Gaithersburg, MD 20899 USA. Univ Politecn Catalunya, Dept Elect Engn, ETSETB, ES-08034 Barcelona, Spain. RP Mason, TO (reprint author), Northwestern Univ, Ctr Adv Cement Based Mat, Dept Mat Sci & Engn, 2225 N Campus Dr, Evanston, IL 60208 USA. RI Mason, Thomas/B-7528-2009; Chen, Wei/A-5694-2010 NR 22 TC 34 Z9 34 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-8846 J9 CEMENT CONCRETE RES JI Cem. Concr. Res. PD APR PY 2000 VL 30 IS 4 BP 585 EP 592 DI 10.1016/S0008-8846(00)00211-8 PG 8 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 328WP UT WOS:000087874400011 ER PT J AU Lynn, JW Rosov, N Barilo, SN Kurnevitch, L Zhokhov, A AF Lynn, JW Rosov, N Barilo, SN Kurnevitch, L Zhokhov, A TI Pr magnetic order and spin dynamics in the cuprates SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT Taiwan International Conference on Superconductivity (TICS 99)/6th Workshop on Low Temperature Physics (WLTP6) CY AUG 17-20, 1999 CL KENTING, TAIWAN SP Natl Sun Yat Sen Univ, Kaohsiung, Dept Phys ID SUPERCONDUCTING PRBA2CU3OX; NEUTRON-DIFFRACTION; CU; SUPPRESSION; RBA2CU3O6+X; STATE AB Magnetic neutron scattering measurements are reviewed for PrBa2Cu3O6+x and compared to related materials that contain Pr. In these materials the magnetic rare earth ordering temperatures are typically an order-of-magnitude higher than for the other rare earths, indicating that exchange interactions dominate the energetics of the magnetic system. For the spin dynamics in Pr123, the strong f-electron hybridization produces non-Fermi liquid-like scattering, which appears to destroy any chance for superconductivity. This behavior contrasts strongly with the sharp crystal field excitations found for the heavy rare earths, as well as with the sharp levels found in other Pr systems. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Belarus Acad Sci, Inst Phys Solids & Semicond, Minsk 220072, Byelarus. Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Russia. RP Lynn, JW (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 45 TC 3 Z9 3 U1 0 U2 2 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 2000 VL 38 IS 2 BP 286 EP 294 PN 2 PG 9 WC Physics, Multidisciplinary SC Physics GA 308FT UT WOS:000086700400013 ER PT J AU Wu, SY Hwang, SR Li, WH Lee, KC Lynn, JW Liu, RS AF Wu, SY Hwang, SR Li, WH Lee, KC Lynn, JW Liu, RS TI Jahn-Teller distortion, charge ordering, and magnetic transitions in Ca-doped NdMnO3 SO CHINESE JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT Taiwan International Conference on Superconductivity (TICS 99)/6th Workshop on Low Temperature Physics (WLTP6) CY AUG 17-20, 1999 CL KENTING, TAIWAN SP Natl Sun Yat Sen Univ, Kaohsiung, Dept Phys AB Structural and magnetic properties of (Nd1-xCax)MnO3, with x = 0, 0.38, and 0.55, have been investigated by means of neutron diffraction and ac magnetic susceptibility measurements. Ca doping induces a structural change to occur at around 250 K, that results in a much fatter unit cell and a significantly shorter axial Mn-O(1) bond length. Both antiferromagnetic and ferromagnetic behaviors were observed. Hole doping shifts the ordering temperature of the Mn spins to a much higher temperature and weakens the antiferromagnetic component as well. Reorientation of the Mn spins were also observed to occur at low temperatures for all three compounds studied. C1 Natl Cent Univ, Dept Phys, Chungli 320, Taiwan. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Natl Taiwan Univ, Dept Chem, Taipei 106, Taiwan. RP Wu, SY (reprint author), Natl Cent Univ, Dept Phys, Chungli 320, Taiwan. RI Liu, Ru-Shi/A-6796-2010 OI Liu, Ru-Shi/0000-0002-1291-9052 NR 7 TC 2 Z9 2 U1 0 U2 2 PU PHYSICAL SOC REPUBLIC CHINA PI TAIPEI PA CHINESE JOURNAL PHYSICS PO BOX 23-30, TAIPEI 10764, TAIWAN SN 0577-9073 J9 CHINESE J PHYS JI Chin. J. Phys. PD APR PY 2000 VL 38 IS 2 BP 354 EP 359 PN 2 PG 6 WC Physics, Multidisciplinary SC Physics GA 308FT UT WOS:000086700400023 ER PT J AU Jones, C Waliser, DE Schemm, JKE Lau, WKM AF Jones, C Waliser, DE Schemm, JKE Lau, WKM TI Prediction skill of the Madden and Julian Oscillation in dynamical extended range forecasts SO CLIMATE DYNAMICS LA English DT Article ID OUTGOING LONGWAVE RADIATION; TROPICAL WESTERN PACIFIC; SEA-SURFACE TEMPERATURE; 40-50 DAY OSCILLATION; INTRASEASONAL OSCILLATION; SYSTEMATIC-ERRORS; HEAT FLUXES; MODEL; NMC; OCEAN AB The Madden and Julian Oscillation (MJO) is the most prominent mode of intraseasonal variations in the tropical region. It plays an important role in climate variability and has a significant influence on medium-to-extended ranges weather forecasting in the tropics. This study examines the forecast skill of the oscillation in a set of recent dynamical extended range forecasts (DERF) experiments performed by the National Centers for Environmental Prediction (NCEP). The present DERF experiments were done with the reanalysis version of the medium range forecast (MRF) model and include 50-day forecasts, initialized once-a-day (0Z) with reanalyses fields, for the period between 1 January, 1985, and 31 December, 1989. The MRF model shows large mean errors in representing intraseasonal variations of the large-scale circulation, especially over the equatorial eastern Pacific Ocean. A diagnostic analysis has considered the different phases of the MJO and the associated forecast skill of the MRF model. Anomaly correlations on the order of 0.3 to 0.4 indicate that skillful forecasts extend out to 5 to 7 days lead-time. Furthermore, the results show a slight increase in the forecast skill for periods when convective anomalies associated with the MJO ate intense. By removing the mean errors, the analysis shows systematic errors in the representation of the MJO with weaker than observed upper level zonal circulations. The examination of the climate run of the MRF model shows the existence of an intraseasonal oscillation, although less intense (50-70%) and with faster (nearly twice as fast) eastward propagation than the observed MJO. The results indicate that the MRF model likely has difficulty maintaining the MJO, which impacts its forecast. A discussion of future work to improve the representation of the MJO in dynamical models and assess its prediction is presented. C1 Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. NOAA, NCEP, Climate Predict Ctr, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Jones, C (reprint author), Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. RI Lau, William /E-1510-2012; OI Lau, William /0000-0002-3587-3691; Jones, Charles/0000-0003-4808-6977 NR 38 TC 65 Z9 76 U1 1 U2 6 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 APR PY 2000 VL 16 IS 4 BP 273 EP 289 DI 10.1007/s003820050327 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 311JF UT WOS:000086880400003 ER PT J AU Kane, S Yohe, G AF Kane, S Yohe, G TI Societal adaptation to climate variability and change: An introduction SO CLIMATIC CHANGE LA English DT Editorial Material C1 NOAA, Off Global Programs, Silver Spring, MD 20910 USA. Wesleyan Univ, Dept Econ, Middletown, CT USA. Carnegie Mellon Univ, Ctr Integrated Study Human Dimens Global Change, Pittsburgh, PA 15213 USA. RP Kane, S (reprint author), NOAA, Off Global Programs, 1100 Wayne Ave,Suite 1210, Silver Spring, MD 20910 USA. NR 0 TC 27 Z9 31 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD APR PY 2000 VL 45 IS 1 BP 1 EP 4 DI 10.1023/A:1005699828901 PG 4 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 323WX UT WOS:000087588900001 ER PT J AU Hall, JM AF Hall, JM TI Untitled - Preface SO CLIMATIC CHANGE LA English DT Editorial Material C1 NOAA, Off Global Programs, Silver Spring, MD 20910 USA. RP Hall, JM (reprint author), NOAA, Off Global Programs, 1100 Wayne Ave,Suite 1225, Silver Spring, MD 20910 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD APR PY 2000 VL 45 IS 1 BP V EP VI PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 323WX UT WOS:000087588900002 ER PT J AU Kane, S Shogren, JF AF Kane, S Shogren, JF TI Linking adaptation and mitigation in climate change policy SO CLIMATIC CHANGE LA English DT Article ID ANTE ECONOMIC VALUE; SELF-PROTECTION; ENDOGENOUS RISK; INSURANCE; INFORMATION; MANAGEMENT; BENEFITS; SCIENCE; CHOICE; MODEL AB How people privately and collectively adapt to climate risk can affect the costs and benefits of public mitigation policy (e.g., Kyoto); an obvious point often neglected in actual policy making. Herein we use the economic theory of endogenous risk to address this optimal mix of mitigation and adaptation strategies, and examine how increased variability in climate change threats affects this mix. We stress that a better understanding of the cross-links between mitigation and adaptation would potentially make it possible to provide more risk reduction with less wealth. Policies that are formulated without considering the cross-links can unintentionally undermine the effectiveness of public sector policies and programs because of unaddressed conflicts between the strategies. We also discuss the cross-disciplinary lessons to be learned from this literature, and identify important research questions to spur discussion in the next round of inquiry. C1 NOAA, Off Global Programs, Silver Spring, MD 20940 USA. Univ Wyoming, Dept Econ & Finance, Laramie, WY 82071 USA. RP Kane, S (reprint author), NOAA, Off Global Programs, Silver Spring, MD 20940 USA. RI Shogren, Jason/B-9771-2017 OI Shogren, Jason/0000-0003-3757-959X NR 72 TC 76 Z9 77 U1 4 U2 29 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD APR PY 2000 VL 45 IS 1 BP 75 EP 102 DI 10.1023/A:1005688900676 PG 28 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 323WX UT WOS:000087588900007 ER PT J AU Wetherbee, BM Nichols, PD AF Wetherbee, BM Nichols, PD TI Lipid composition of the liver oil of deep-sea sharks from the Chatham Rise, New Zealand SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY LA English DT Article DE deep-sea sharks; diacyl glyceryl ether; liver oil; squalene; buoyancy ID ANTITUMOR-ACTIVITY; SQUALENE CONTENT; WATERS; SCYMNODON; CAUGHT AB Deep-sea sharks approach neutral buoyancy by means of a large liver that contains large amounts of low-density lipids, primarily squalene and diacyl glyceryl ether (DAGE). As an animal increases in size and matures sexually, many biochemical changes take place within the animal. It was hypothesized that maintenance of neutral buoyancy in deep-sea sharks involves fine-scale changes in the chemical composition of the liver oil as individual sharks grow and develop. To test this hypothesis, the lipid composition of liver oil for individuals of different size and sex of deep-sea sharks from the Chatham Rise, New Zealand was compared. The composition of liver oil varied within and among species. Several species contained large amounts of squalene and DAGE, whereas only traces of these lipids were present in other species. The amounts of squalene and DAGE in liver oil were inversely related, and squalene content tended to decrease as sharks increased in size. Species with high squalene levels (>80%) in liver oil were not abundant on the Chatham Rise, although levels of DAGE (a lipid of increasing commercial interest) were elevated in many species. Maintenance of neutral buoyancy in deep-sea sharks appears to involve changes in the composition of low-density liver lipids as the sharks increase in size and mature. (C) 2000 Elsevier Science Inc. All rights reserved. C1 Univ Hawaii, Dept Zool, Honolulu, HI 96822 USA. CSIRO, Div Marine Res, Hobart, Tas 7001, Australia. RP Wetherbee, BM (reprint author), NOAA, Natl Marine Fisheries Serv, NEFSC, 28 Tarzwell Dr, Narragansett, RI 02882 USA. RI Nichols, Peter/C-5128-2011 NR 51 TC 39 Z9 41 U1 2 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0305-0491 J9 COMP BIOCHEM PHYS B JI Comp. Biochem. Physiol. B-Biochem. Mol. Biol. PD APR PY 2000 VL 125 IS 4 BP 511 EP 521 DI 10.1016/S0305-0491(00)00154-1 PG 11 WC Biochemistry & Molecular Biology; Zoology SC Biochemistry & Molecular Biology; Zoology GA 322YU UT WOS:000087537800008 PM 10904864 ER PT J AU Long, ER AF Long, ER TI Degraded sediment quality in US estuaries: A review of magnitude and ecological implications SO ECOLOGICAL APPLICATIONS LA English DT Article; Proceedings Paper CT 3rd Annual Conference on Fisheries, Habitat, and Pollution CY NOV 06-08, 1997 CL CHARLESTON, SC SP Natl Marine Fisheries Serv, NOAA, Coastal Serv Ctr, LLC, Atlantic States Marine Fisheries Commiss, S Carolina Sea Grant Consortium, S Carolina Dept Nat Resources, Univ S Carolina, Belle W Brauch Inst Marine Biol & Costal Res, TerrAqua Environm Sci & Policy DE amphipod bioassays; degraded benthos; estuaries; fisheries, habitat, and pollution; sediment quality guidelines (SQG); sediment quality triad; sediment toxicity ID INFAUNAL COMMUNITY COMPOSITION; SAN-FRANCISCO BAY; COMMENCEMENT BAY; MARINE-SEDIMENTS; TOXICITY; CONTAMINATION; TRIAD; WASHINGTON; GUIDELINES; VETULUS AB Potentially toxic substances that accumulate in the sediments of estuaries can become sufficiently concentrated to be harmful to valuable living resources. Although contamination of U.S. estuarine sediments is widely recognized as a serious problem, the actual severity and extent of this problem is poorly known on a national scale. Data derived from chemical analyses, toxicity tests, and benthic community analyses of sediments (constituting the sediment quality triad) were reviewed. The objectives of this review were to estimate the incidence of chemical contamination and the spatial extent of toxicity and degraded benthic communities, and to evaluate the relative degree of correspondence between matching pairs of the triad components. Based upon two inventories of data compiled from numerous studies, similar to 26-27% of sediment samples nationwide had chemical concentrations sufficiently high to warrant concern for potential toxicological effects. The spatial extent of toxicity in acute amphipod bioassays ranged from 0% to 85% among urban bays and estuaries, and averaged similar to 7.5% of the surficial areas studied thus far. Among three estuarine provinces, the surficial extent of degraded benthos ranged from 7% to 22% for measures of low infaunal abundance, and from 4% to 10% for measures of low species richness. The percentages of samples with slightly elevated chemical concentrations (42-49%) and the spatial extent of toxicity in sensitive, sublethal bioassays (43-61% of estuarine surficial area) indicated that slightly degraded conditions were much more widespread. Data compiled in many field studies conducted along portions of all three coasts of the United States, indicated that numerical sediment quality guidelines could be used to predict toxicity in sediments, and that results of laboratory toxicity tests often were predictive of degraded benthos. C1 NOAA, NOS, Ctr Coastal Monitoring & Assessment, Seattle, WA 98115 USA. RP Long, ER (reprint author), NOAA, NOS, Ctr Coastal Monitoring & Assessment, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 47 TC 41 Z9 42 U1 1 U2 6 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 1051-0761 EI 1939-5582 J9 ECOL APPL JI Ecol. Appl. PD APR PY 2000 VL 10 IS 2 BP 338 EP 349 DI 10.1890/1051-0761(2000)010[0338:DSQIUS]2.0.CO;2 PG 12 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 296DT UT WOS:000086008300003 ER PT J AU Spina, AP AF Spina, AP TI Habitat partitioning in a patchy environment: Considering the role of intraspecific competition SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE stream fish; headwater stream; biotic interaction; size specific habitat use; removal experiment ID TROUT SALMO-TRUTTA; STREAM FISHES; RAINBOW-TROUT; SIZE CLASSES; SELECTION; SEGREGATION; POSITIONS; RESPONSES; PREDATION; MINNOWS AB Coexistence of many size groups of conspecifics in habitat patches may complicate resource partitioning and increase intraspecific interactions. The objectives of my study were to determine partitioning of habitat among age groups of rainbow trout, Oncorhynchus mykiss, coexisting in pool habitat of a headwater stream, and to determine the role of intraspecific competition for such resource partitioning. The trout population showed size and age specific patterns of habitat use, and trout selected locations based on depth and longitudinal position. This habitat use pattern decreased intraspecific overlap among the trout age groups for use of pool space. I used a removal experiment to determine if two-year old trout constrained habitat use by the smaller conspecifics. Although the experimental results imply that recent intraspecific competition was not present, the absence of competitive exclusion was not clearly demonstrated because of low experimental power. While this study identified habitat partitioning among the trout age groups, it remains unclear whether biotic interactions or size specific requirements were causing the habitat use patterns. C1 Calif State Polytech Univ Pomona, Dept Biol Sci, Pomona, CA 91768 USA. RP Spina, AP (reprint author), Natl Marine Fisheries Serv, Habitat Conservat Div, SW Region,501 W Ocean Blvd,Suite 4200, Long Beach, CA 90802 USA. NR 33 TC 20 Z9 20 U1 1 U2 9 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD APR PY 2000 VL 57 IS 4 BP 393 EP 400 DI 10.1023/A:1007682010268 PG 8 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 288EW UT WOS:000085550100005 ER PT J AU Patz, JA McGeehin, MA Bernard, SM Ebi, KL Epstein, PR Grambsch, A Gubler, DJ Reiter, P Romieu, I Rose, JB Samet, JM Trtanj, J AF Patz, JA McGeehin, MA Bernard, SM Ebi, KL Epstein, PR Grambsch, A Gubler, DJ Reiter, P Romieu, I Rose, JB Samet, JM Trtanj, J TI The potential health impacts of climate variability and change for the United States: Executive summary of the report of the health sector of the US National Assessment SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Review DE air pollution; climate change; flooding; global warming; heat waves; vectorborne diseases; waterborne diseases ID 1995 HEAT-WAVE; VIBRIO-VULNIFICUS; FOODBORNE DISEASES; INNER-CITY; TEMPERATURE; MORTALITY; TRENDS; PRECIPITATION; FREQUENCY; OUTBREAK AB We examined the potential impacts of climate variability and change on human health as part of a congressionally mandated study of climate change in the United States. Our author team, comprising experts from academia, government, and the private sector, was selected by the federal interagency U.S. Global Change Research Program, and this report stems from our first 18 months of work For this assessment we used a set of assumptions and/or projections of future climates developed for all participants in the National Assessment of the Potential Consequences of Climate Variability and Change. We identified five categories of health outcomes that are most likely to be affected by climate change because they are associated with weather and/or climate variables: temperature-related morbidity and mortality; health effects of extreme weather events (storms, tornadoes, hurricanes, and precipitation extremes); air-pollution-related health effects; water- and foodborne diseases; and vector- and rodentborne diseases. We concluded that the levels of uncertainty preclude any definitive statement on the direction of potential future change for each of these health outcomes, although we developed some hypotheses. Although we mainly addressed adverse health outcomes, we identified some positive health outcomes, notably reduced cold-weather mortality, which has not been extensively examined. We found that at present most of the U.S. population is protected against adverse health outcomes associated with weather and/or climate, although certain demographic and geographic populations are at increased risk. We concluded that vigilance in the maintenance and improvement of public health systems and their responsiveness to changing climate conditions and to identified vulnerable subpopulations should help to protect the U.S. population from any adverse health outcomes of projected climate change. C1 Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Environm Hlth Sci, Program Hlth Effects Global Environm Change, Baltimore, MD 21205 USA. US Ctr Dis Control & Prevent, Natl Ctr Environm Hlth, Atlanta, GA USA. EPRI, Palo Alto, CA USA. Harvard Univ, Sch Med, Ctr Hlth & Global Environm, Boston, MA USA. US EPA, Off Res & Dev, Washington, DC 20460 USA. US Ctr Dis Control & Prevent, Div Vector Borne Dis, Ft Collins, CO USA. US Ctr Dis Control & Prevent, Div Vector Borne Dis, San Juan, PR USA. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Epidemiol, Baltimore, MD USA. NOAA, Off Global Program, Silver Spring, MD USA. RP Patz, JA (reprint author), Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Environm Hlth Sci, Program Hlth Effects Global Environm Change, 615 N Wolfe St, Baltimore, MD 21205 USA. NR 122 TC 107 Z9 112 U1 1 U2 39 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 APR PY 2000 VL 108 IS 4 BP 367 EP 376 DI 10.2307/3454357 PG 10 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 306KT UT WOS:000086596400035 PM 10753097 ER PT J AU Feist, BE Simenstad, CA AF Feist, BE Simenstad, CA TI Expansion rates and recruitment frequency of exotic smooth cordgrass, Spartina alterniflora (Loisel), colonizing unvegetated littoral flats in Willapa Bay, Washington SO ESTUARIES LA English DT Article ID SAN-FRANCISCO BAY; SALT-MARSH; POACEAE; SPREAD; INVASIONS; HYBRIDIZATION; CALIFORNIA; ORGANISMS; ESTUARIES; FOLIOSA AB We estimated lateral growth rates of nonindigenous Spartina alterniflora patches in Willapa Bay, Washington, over three intervals between 1970 and 1990, to reconstruct recruitment frequency since S. alterniflora was initially introduced c. 1890. Black and white aerial photographs (1:24,000 scale) of four representative sites where S. alterniflora has invaded were analyzed. Individual patches were digitized on a computer, and diameter and area were computed for each patch for all years and sites sampled using CAD software. Lateral growth rates of individual S. alterniflora patches increased linearly at 79.3 (+/- 1.674 SE) cm yr(-1). Back calculations of origin dates for individual patches based on mean lateral growth rates indicate that recruitment of new patches has been episodic and increasing in frequency since initial introduction. Environmental factors such as sea surface temperature, sea level, and precipitation may account for some of this recruitment variability. These data may be useful in existing and future models of S. alferniflora expansion in Pacific Northwest estuaries. C1 Univ Washington, Sch Fisheries, Wetland Ecosyst Team, Seattle, WA 98195 USA. RP Feist, BE (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. OI Feist, Blake/0000-0001-5215-4878 NR 44 TC 39 Z9 47 U1 1 U2 12 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD APR PY 2000 VL 23 IS 2 BP 267 EP 274 DI 10.2307/1352832 PG 8 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 324MT UT WOS:000087626500009 ER PT J AU Grull, H Schreyer, A Berk, NF Majkrzak, CF Han, CC AF Grull, H Schreyer, A Berk, NF Majkrzak, CF Han, CC TI Composition profiling in a binary polymer blend thin film using polarized neutron reflectivity SO EUROPHYSICS LETTERS LA English DT Article ID SURFACE PHASE-BEHAVIOR; MODEL-CALCULATIONS; POLYOLEFIN BLENDS; MIXTURES; REFLECTOMETRY; ENRICHMENT; SEGREGATION; INVERSION; SPECTROMETRY; COEXISTENCE AB The concentration profile in an ultra-thin film (film thickness d = 435 Angstrom) of a high molecular mass-poly(isoprene)/deuterated poly(butadiene) blend is measured in the bulk system's miscible region with a new polarized neutron reflectivity method. By using a buried ferromagnetic layer inside the wafer and a polarized neutron beam, it is possible to obtain the neutron specular reflection amplitude A including its phase angle phi. Conventional reflectivity measurements only determine the reflected intensity I = A(2) which does not contain information on the phase angle. Only the knowledge of the phase angle allows an unambiguous determination of the neutron scattering length density profile of the film. The scattering length density profile thus obtained reveals poly(isoprene) segregating symmetrically to the polymer/air and polymer/Si interfaces. The adsorption profile at both interfaces can be approximately described using an exponential- or tanh-function with a decay constant smaller than the bulk correlation length. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Ruhr Univ Bochum, Inst Expt Phys Festkorperphys, D-44780 Bochum, Germany. RP Grull, H (reprint author), Ben Gurion Univ Negev, Dept Chem Engn, POB 653, IL-84105 Beer Sheva, Israel. NR 31 TC 17 Z9 17 U1 1 U2 5 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD APR PY 2000 VL 50 IS 1 BP 107 EP 112 DI 10.1209/epl/i2000-00242-8 PG 6 WC Physics, Multidisciplinary SC Physics GA 302XB UT WOS:000086390800017 ER PT J AU Cooper, LY AF Cooper, LY TI Simulating the opening of fusible-link-actuated fire vents SO FIRE SAFETY JOURNAL LA English DT Article ID SPRINKLER AB Model equations, suitable for general use in compartment fire models, are developed to simulate the thermal response to arbitrary fire environments of fusible-link-activated automatic fire vents. The method of analysis, which focused on a prototype three-element link-mount design, can be extended to arbitrary multiple-element link mounts, including single-element simply supported links. A method was developed to determine the values of the set of parameters that characterize a particular multiple link-mount design. This involves: (1) the measured time-dependent thermal response of the link-mount design to exposure in a plunge test, the type of test used to characterize the thermal response of sprinkler links, and (2) an analytic means of determining values of the design parameters that yield an optimum fit between a solution to the model equations and the temperature data. The method takes account of the pre-fusing solder-melting phase of fusible-link response. The latter was shown to be very important for the link design used in this study. The method was carried out successfully for four plunge tests involving three link-mount systems and one or two system/flow orientations. The resulting system parameters and model equations were used in a successful simulation of vent actuation in a real, large-scale, fire scenario. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Cooper, LY (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 20 TC 0 Z9 0 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD APR PY 2000 VL 34 IS 3 BP 219 EP 255 DI 10.1016/S0379-7112(99)00042-9 PG 37 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 317ZR UT WOS:000087259000001 ER PT J AU Brewster-Geisz, KK Miller, TJ AF Brewster-Geisz, KK Miller, TJ TI Management of the sandbar shark, Carcharhinus plumbeus: implications of a stage-based model SO FISHERY BULLETIN LA English DT Article ID WESTERN NORTH-ATLANTIC; GROWTH; SEA; TURTLES; ANCHOVY; AGE AB Sandbar sharks (Carcharhinus plumbeus) support an important commercial fishery. They are managed as a component of a multispecies group, termed large coastal sharks, by the National Marine Fisheries Service (NMFS) under the Fishery Management Plan (FMP) for Atlantic sharks. Currently, large coastal sharks, generally, and sandbar sharks, specifically, are considered overfished. Several management options, including nursery ground closures and size limits, are being considered to conserve the fishery. We explored the implications of management options for large coastal sharks within the framework of a stage-based model. Based on biological criteria, the life cycle of the sandbar shark was represented as five juvenile, subadult, pr resting adults. The model followed only females. From a fishing mortality rate (F) of 0.20, estimated in the 1996 stock evaluation workshop (SEW), the model projects a population decline to 13% of its current abundance within 20 years. The population is not stabilized until F is reduced to 0.07. In one run of the model, we assumed that F on neonates and pregnant adults was zero in order to assess the impact of a "perfect" nursery ground closure. Under this scenario, the population continued to decline unless F on the remaining stages was reduced to 0.097. Even with the closure of nursery grounds or the introduction of size limits to protect neonates and juveniles, F has to be reduced substantially. The model is highly sensitive to the dynamics of juveniles and subadults, which implies that management should protect these immature sharks to rebuild the stock. C1 Natl Marine Fisheries Serv, Highly Migratory Species Management Div, Silver Spring, MD 20910 USA. Univ Maryland, Chesapeake Biol Lab, Ctr Environm Sci, Solomons, MD 20688 USA. RP Brewster-Geisz, KK (reprint author), Natl Marine Fisheries Serv, Highly Migratory Species Management Div, 1315 East West Highway, Silver Spring, MD 20910 USA. RI Miller, Thomas/C-2129-2008 OI Miller, Thomas/0000-0001-8427-1614 NR 25 TC 40 Z9 41 U1 2 U2 9 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 236 EP 249 PG 14 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800002 ER PT J AU Lo, NCH Hunter, JR Churnside, JH AF Lo, NCH Hunter, JR Churnside, JH TI Modeling statistical performance of an airborne lidar survey system for anchovy SO FISHERY BULLETIN LA English DT Article ID NORTHERN ANCHOVY; ENGRAULIS-MORDAX; FISH; SCHOOLS AB The objective of our study was to model the performance of an airborne lidar survey system for northern anchovy in terms of survey accuracy and precision. Our analyses indicated that swath width would have little or no effect on the probability that at least one fish school would be encountered. In typical coastal waters off California (attenuation coefficient=0.1/m), about half of the schools were detected by the lidar during the day and about 64% during the night. A greater proportion of schools were detected during the night because anchovy have a shallow vertical distribution, whereas in the day, schools may extend down to 155 m; schools below about 40 m depth were not detectable to the laser. Although schools tended to be more diffuse during the night than during the day, even the very diffuse schools of anchovy (0.5 fish/m(3)) were detectable at night throughout the upper 20 m of the water column with a lidar. With a substantial increase in instrument and survey costs, it would be possible to increase the equivalent laser-pulsed power by a factor of 10 over that of the "off-the-shelf system," as used in our model. Such a change would increase the maximum detection depth of the lidar system by about 10 m but would have a negligible effect on the probability of detecting schools during the day owing to the skewed vertical distribution of anchovy schools. More effective approaches for improving the accuracy and precision of potential lidar surveys for fisheries would be to improve school detection algorithms and to develop a lidar survey model based on line transect theory to obtain an unbiased estimate of abundance. To produce an accurate reconstruction of the average vertical distribution of schools for a particular season and region, a synthesis of acoustic and lidar surveys of school distribution is required. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Environm Technol Lab, Ocean Remote Sensing Div, Boulder, CO 80303 USA. RP Lo, NCH (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. RI Churnside, James/H-4873-2013 NR 29 TC 8 Z9 10 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 264 EP 282 PG 19 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800004 ER PT J AU Mortensen, D Wertheimer, A Taylor, S Landingham, J AF Mortensen, D Wertheimer, A Taylor, S Landingham, J TI The relation between early marine growth of pink salmon, Oncorhynchus gorbuscha, and marine water temperature, secondary production, and survival to adulthood SO FISHERY BULLETIN LA English DT Article ID PRINCE-WILLIAM-SOUND; VALDEZ OIL-SPILL; CHUM SALMON; JUVENILE PINK; O-KETA; SELECTIVE PREDATION; BRITISH-COLUMBIA; PUGET SOUND; MORTALITY; KISUTCH AB Juvenile pink salmon, Oncorhynchus gorbuscha, from four consecutive brood years were tagged as they emigrated to the estuarine waters of Auke Bay, and information was obtained on the relationships between early marine growth, environmental conditions, and survival to adulthood. Juveniles that emigrated from Auke Creek later in the spring spent significantly less time in the estuary. Individual growth rates of tagged fish recovered in Auke Bay ranged from 3.1% to 7.1% per day. In all study years, juvenile pink salmon grew more slowly in early April than in late April and early May. Water temperature and growth were significantly correlated in all years, but growth did not consistently correlate with the biomass of epibenthic prey or zooplankton available to the fish. Comparisons of expected and observed growth rates suggested that low prey availability, as well as low temperatures, may have limited growth for early spring emigrants. Although early emigrants encountered poorer growth conditions, survivors were larger at a given date than later emigrants, their larger size possibly protecting them from size-selective predation. Early marine growth was significantly related to intra-annual cohort survival to adults (r(2)=0.65, P<0.05). Larger fish consistently survived better than their smaller cohorts for all years. Although early marine growth was an important determinate of survival within a cohort of pink salmon, other factors, such as predator abundance, contributed to the large interannual variability observed. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Mortensen, D (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM don.mortensen@noaa.gov NR 44 TC 42 Z9 42 U1 1 U2 17 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 319 EP 335 PG 17 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800008 ER PT J AU Rocha-Olivares, A Moser, HG Stannard, J AF Rocha-Olivares, A Moser, HG Stannard, J TI Molecular identification and description of pelagic young of the rockfishes Sebastes constellatus and Sebastes ensifer SO FISHERY BULLETIN LA English DT Article ID GENUS SEBASTES; FAMILY SCORPAENIDAE; JUVENILES; LARVAE; CALIFORNIA; HELVOMACULATUS; EVOLUTION; ECOLOGY; GROWTH AB Five rockfish juveniles (15.0-30.4 mm SL) collected in midwater trawls from offshore banks off the coast of California were identified by using a combination of morphological and molecular characters. All had pigment patterns consistent with members of the subgenus Sebastomus, but each required the use of molecular markers for species identification. Using DNA sequence data from the mitochondrial cytochrome b, we identified the juveniles as a transforming larva of Sebastes constellatus and a transforming larva and three pelagic juveniles of S. ensifer. We provide detailed descriptions of the specimens and compare our results with the developmental stages of other species of Sebastes of the subgenus Sebastomus. We found some differences in structure and pigmentation that might allow identification of these young stages by traditional means, but more descriptive work is necessary. The use of molecular tools can thus be successfully used to complement traditional identification efforts to solve problems unassailable by morphological and pigment characters alone. C1 Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70809 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla Lab, La Jolla, CA 92038 USA. RP Rocha-Olivares, A (reprint author), Louisiana State Univ, Dept Biol Sci, 508 Life Sci Bldg, Baton Rouge, LA 70809 USA. RI Rocha-Olivares, Axayacatl/A-9832-2008 OI Rocha-Olivares, Axayacatl/0000-0002-2700-9086 NR 33 TC 19 Z9 19 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 353 EP 363 PG 11 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800011 ER PT J AU Schaefer, KM Oliver, CW AF Schaefer, KM Oliver, CW TI Shape, volume, and resonance frequency of the swimbladder of yellowfin tuna, Thunnus albacares SO FISHERY BULLETIN LA English DT Article ID ACOUSTIC SCATTERING; TARGET STRENGTH; FISH; MODEL AB The shapes and volumes of swimbladders of yellowfin tuna, Thunnus albacares, were measured from freshly caught fish from the eastern Pacific Ocean. Direct measurements of swimbladder volumes were obtained from a geometric reconstruction with morphometric measurements of intact bladders and by volumetric displacements of the same intact bladders excised from 46 fish (57 to 157 cm in length). The estimates of the swimbladder volumes obtained from geometric reconstruction were not significantly different from those obtained with the corresponding volumetric displacements. There is a nonlinear relationship between yellowfin swimbladder volumes and fish lengths. The mean swimbladder volume was 1.33% of body volume with a minimum of 0.30% and a maximum of 2.84%. A comprehensive model, based on the data from this study and those from a previous investigation, is presented for the relationship of yellowfin swimbladder volumes, estimated From geometric reconstruction and fish lengths for 108 specimens (35 to 157 cm). This predictive model was then used with other formulae to estimate yellowfin tuna swimbladder resonance frequencies for fish lengths and fish depths. Because these resonance frequencies are within the range of frequencies audible to yellowfin tuna, we speculate on the potential distance at which dolphins could be detected by yellowfin tuna. C1 Inter Amer Trop Tuna Commiss, La Jolla, CA 92037 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Schaefer, KM (reprint author), Inter Amer Trop Tuna Commiss, 8604 La Jolla Shores Dr, La Jolla, CA 92037 USA. RI Rohlf, F/A-8710-2008 NR 42 TC 7 Z9 7 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 364 EP 374 PG 11 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800012 ER PT J AU Stevens, BG Vining, I Byersdorfer, S Donaldson, W AF Stevens, BG Vining, I Byersdorfer, S Donaldson, W TI Ghost fishing by Tanner crab (Chionoecetes bairdi) pots off Kodiak, Alaska: pot density and catch per trap as determined from sidescan sonar and pot recovery data SO FISHERY BULLETIN LA English DT Article AB Sidescan sonar was used to locate 189 putative lost crab pots in a 4.5 km(2) area of Chiniak Bay, near Kodiak, Alaska. Subsequent observations of 15 such objects by submersible and ROV verified that they were indeed crab pots. In 1995 and 1996, 147 pots were recovered from the surveyed and adjacent nonsurveyed areas by grappling, and their condition and contents were examined. Tanner crabs, Chionoecetes bairdi, were the most abundant organism, with 227 found in 24 pots (16% frequency of occurrence); sun-flower sea stars (Pycnopodia helianthoides) were the most frequent (42%) occupant and second most abundant (189 in 62 pots). Octopuses (Octopus dofleini) were significantly associated with pots containing Tanner crabs. Occurrence of crabs in pots was primarily a function of background crab density and differed between the surveyed and nonsurveyed areas. Recently lost pots (< 1 yr old) had significantly more male crabs, significantly larger male crabs, and contained seven times more total crabs than older pots (those lost two or more years prior to recovery). The proportion of pots with damaged webbing increased with pot age, but holes in pot webbing did not significantly affect catch per pot. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Kodiak, AK 99615 USA. Alaska Dept Fish & Game, Kodiak, AK 99615 USA. RP Stevens, BG (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 301 Res Ct, Kodiak, AK 99615 USA. NR 23 TC 20 Z9 21 U1 0 U2 4 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 389 EP 399 PG 11 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800014 ER PT J AU Ahrenholz, DW Squires, DD Rice, JA Nixon, SW Fitzhugh, GR AF Ahrenholz, DW Squires, DD Rice, JA Nixon, SW Fitzhugh, GR TI Periodicity of increment formation in otoliths of overwintering postlarval and prejuvenile Atlantic menhaden, Brevoortia tyrannus SO FISHERY BULLETIN LA English DT Article ID NORTH-CAROLINA; LARVAL; AGE; MICROSTRUCTURE; TEMPERATURE; SURVIVAL C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Beaufort Lab, Beaufort, NC 28516 USA. N Carolina State Univ, Dept Zool, Raleigh, NC 27695 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Panama City Facil, Panama City, FL 32408 USA. RP Ahrenholz, DW (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Beaufort Lab, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 21 TC 4 Z9 4 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 421 EP 426 PG 6 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800017 ER PT J AU Powell, AA Lindquist, DG Hare, JA AF Powell, AA Lindquist, DG Hare, JA TI Larval and pelagic juvenile fishes collected with three types of gear in Gulf Stream and shelf waters in Onslow Bay, North Carolina, and comments on ichthyoplankton distribution and hydrography SO FISHERY BULLETIN LA English DT Article C1 NOAA, Natl Ocean Serv, Beaufort Lab, Ctr Coastal Fisheries & Habitat Res, Beaufort, NC 28516 USA. Univ N Carolina, Dept Biol Sci, Wilmington, NC 28403 USA. Univ N Carolina, Marine Sci Res Ctr, Wilmington, NC 28403 USA. RP Powell, AA (reprint author), NOAA, Natl Ocean Serv, Beaufort Lab, Ctr Coastal Fisheries & Habitat Res, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. EM allyn.powell@noaa.gov NR 24 TC 15 Z9 17 U1 0 U2 2 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 EI 1937-4518 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 2000 VL 98 IS 2 BP 427 EP 438 PG 12 WC Fisheries SC Fisheries GA 308BN UT WOS:000086688800018 ER PT J AU Baker, DM Larsen, DA Swanson, P Dickhoff, WW AF Baker, DM Larsen, DA Swanson, P Dickhoff, WW TI Long-term peripheral treatment of immature coho salmon (Oncorhynchus kisutch) with human leptin has no clear physiologic effect SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID RADIOIMMUNOASSAY; HORMONES; CLONING; ONSET; MICE; GENE AB The effects of long-term peripheral exposure to recombinant human leptin were tested in immature coho salmon under both fed and fasted conditions. We found that high circulating levels of human leptin did not alter growth, energy stores, gonad weight, pituitary content of follicle-stimulating hormone, or plasma levels of insulin-like growth factor-I, insulin, growth hormone, or thyroxine. (C) 2000 Academic Press. C1 Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Baker, DM (reprint author), Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. NR 20 TC 60 Z9 67 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD APR PY 2000 VL 118 IS 1 BP 134 EP 138 DI 10.1006/gcen.1999.7450 PG 5 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 304TW UT WOS:000086501100015 PM 10753575 ER PT J AU Hansell, DA Feely, RA AF Hansell, DA Feely, RA TI Atmospheric intertropical convergence impacts surface ocean carbon and nitrogen biogeochemistry in the western tropical Pacific SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTHERN-HEMISPHERE CIRCULATION; DISSOLVED ORGANIC NITROGEN; SARGASSO SEA; TEMPERATURE; INPUTS AB Concentrations of inorganic and organic carbon and organic nitrogen, as well as other hydrographic and biogeochemical variables, were measured in the oligotrophic waters of the western South Pacific Ocean (5-35 degrees S; 170 degrees W). With those data, we assess the impact of the intertropical convergences of the western tropical Pacific Ocean on surface ocean biogeochemistry. Low salinity, oligotrophic waters of the western tropical Pacific underlying regions of high net precipitation are characterized by concentrations of organic carbon and nitrogen that are elevated relative to higher salinity (lower net precipitation) zones. We hypothesize that water column stratification, forced by high net precipitation, favors enhanced rates of N-2 fixation, with resultant elevation of organic carbon and nitrogen concentrations in the region. An effect of anthropogenic ocean warming and the associated increased hydrologic cycle in the tropical Pacific may be to alter the biogeochemical cycling of carbon and nitrogen through enhancement of N-2 fixation. C1 Bermuda Biol Stn Res Inc, GE-01 St Georges, Bermuda. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Hansell, DA (reprint author), Bermuda Biol Stn Res Inc, 17 Biol Lane, GE-01 St Georges, Bermuda. OI Hansell, Dennis/0000-0001-9275-3445 NR 27 TC 23 Z9 24 U1 0 U2 4 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 APR 1 PY 2000 VL 27 IS 7 BP 1013 EP 1016 DI 10.1029/1999GL002376 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 299XV UT WOS:000086224500027 ER PT J AU Klemic, GA Shobe, J Sengupta, S AF Klemic, GA Shobe, J Sengupta, S TI Environmental dosimetry performance criteria: Pilot test of proposed ANSI Draft Standard N13.29 SO HEALTH PHYSICS LA English DT Article DE monitoring; environmental; radiation; environmental; detector; radiation; standards AB American National Standards Institute (ANSI) standards are a source of technical guidance on the application of passive radiation detectors in personnel and environmental monitoring programs. The proposed new ANSI Draft N13.29 describes performance tests for environmental dosimetry providers that are analogous to those now required in personnel dosimetry. The objective of this study was to pilot test the procedural specifications before Draft N13.29 is submitted for final balloting, The results of the performance tests are relevant to environmental surveillance programs, which may be affected if Draft N13.29 is approved. Seven environmental dosimetry providers submitted dosimeters for the pilot test, which included two phases. The first phase involved exposing dosimeters to laboratory gamma, beta, and x-ray sources at routine and accident dose levels. In the second phase, dosimeters were subjected to 90 d of simulated environmental conditions in a chamber that cycled through prescribed temperature and humidity parameters and lighting conditions. Two participants passed all categories of the laboratory test phase, and all seven passed the environmental test phase. We report here on the results of the performance tests; additional results relevant to finalizing Draft N13.29 are detailed elsewhere. C1 US DOE, Environm Measurements Lab, New York, NY 10014 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. EM klemic@eml.doe.gov NR 16 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD APR PY 2000 VL 78 IS 4 BP 370 EP 376 DI 10.1097/00004032-200004000-00002 PG 7 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 294UY UT WOS:000085929800002 PM 10749521 ER PT J AU Hofmann, W Menache, MG Crawford-Brown, DJ Caswell, RS Karam, LR AF Hofmann, W Menache, MG Crawford-Brown, DJ Caswell, RS Karam, LR TI Modeling energy deposition and cellular radiation effects in human bronchial epithelium by radon progeny alpha particles SO HEALTH PHYSICS LA English DT Article DE alpha particles; radon progeny; lungs; human; microdosimetry ID CULTURED MAMMALIAN-CELLS; STATE-VECTOR MODEL; C3H 10T1/2 CELLS; ONCOGENIC TRANSFORMATION; RESPIRATORY-TRACT; CHINESE-HAMSTER; X-RAYS; BIOLOGICAL EFFECTIVENESS; LUNG-TISSUE; DOSE-RATE AB Energy deposition and cellular radiation effects arising from the interaction of single Po-218 and Po-214 alpha particles with basal and secretory cell nuclei were simulated for different target cell depths in the bronchial epithelium of human airway generations 2, 4, 6, and 10. To relate the random chord lengths of alpha particle tracks through spherical cell nuclei to the resulting biological endpoints, probabilities per unit track length for different cellular radiation effects as functions of LET were derived from in vitro experiments. The radiobiological data employed in the present study were inactivation and mutation (mutant frequency at the HPRT gene) in V79 Chinese hamster cells and inactivation and transformation in C3H 10T1/2 cells. Based on computed LET spectra and relative frequencies of target cells, probabilities for transformation, mutation, and cell killing in basal and secretory cells were computed for a lifetime exposure of 20 WLM. While predicted transformation probabilities were about two orders of magnitude higher than mutation probabilities, they were still about two orders of magnitude lower than inactivation probabilities. Furthermore transformation probabilities for basal cells are generally higher than those for secretory cells, and Po-214 alpha particles are primarily responsible for transformations in bronchial target cells. C1 Salzburg Univ, Inst Phys & Biophys, A-5020 Salzburg, Austria. Duke Univ, Med Ctr, Ctr Extrapolat Modeling, Durham, NC 27710 USA. Univ N Carolina, Inst Environm Studies, Chapel Hill, NC 27599 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM Werner.Hofmann@sbg.ac.at NR 58 TC 22 Z9 22 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 APR PY 2000 VL 78 IS 4 BP 377 EP 393 DI 10.1097/00004032-200004000-00003 PG 17 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 294UY UT WOS:000085929800003 PM 10749522 ER PT J AU Seem, JE House, JM Kelly, GE Klaassen, CJ AF Seem, JE House, JM Kelly, GE Klaassen, CJ TI A damper control system for preventing reverse airflow through the exhaust air damper of variable-air-volume air-handling units SO HVAC&R RESEARCH LA English DT Article ID VAV SYSTEMS; MINIMUM AB Traditional air-handling unit (AHU) control systems link the position of the exhaust, recirculation, and outdoor air dampers. Laboratory rests of a variable-air-volume AHU using the traditional damper control approach revealed that outdoor air could enter the AHU through the exhaust air damper. This can negatively impact indoor air quality. This paper examines the conditions that lead to this phenomenon and presents a new control system that can help alleviate the problem. The new control system links only the position of the exhaust and recirculation air dampers. During occupied rimes, the outdoor air damper is fully open. Simulation results are presented that demonstrate that the new damper control system prevents air from entering the AHU through the exhaust air outlet for all but extreme conditions that are described in the paper. Laboratory and field rest results are presented that demonstrate that the new control system prevents air from entering the AHU through the exhaust air outlet for the same conditions that cause significant reverse airflow for the traditional control system. Furthermore, reverse airflow tvas not observed for any of the conditions examined in the laboratory! and field tests when the new control system was used. C1 Johnson Controls Inc, Milwaukee, WI 53201 USA. NIST, Bldg & Fire Res Lab, Bldg Environm Div, Gaithersburg, MD 20899 USA. Iowa Energy Ctr Energy Resource Stn, Ankeny, IA USA. RP Seem, JE (reprint author), Johnson Controls Inc, Milwaukee, WI 53201 USA. NR 10 TC 7 Z9 7 U1 0 U2 0 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 1078-9669 J9 HVAC&R RES JI HVAC&R Res. PD APR PY 2000 VL 6 IS 2 BP 135 EP 148 DI 10.1080/10789669.2000.10391254 PG 14 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 305GP UT WOS:000086531300003 ER PT J AU Fogarty, MJ AF Fogarty, MJ TI Recruitment dynamics of exploited marine populations: Physical-biological interactions - Symposium overview SO ICES JOURNAL OF MARINE SCIENCE LA English DT Reprint C1 Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, NOAA, Woods Hole, MA 02543 USA. Univ Maryland, Ctr Environm & Estuarine Studies, Solomons, MD 20688 USA. RP Fogarty, MJ (reprint author), Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, NOAA, Woods Hole, MA 02543 USA. NR 0 TC 2 Z9 2 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 189 EP 190 PG 2 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900002 ER PT J AU Brodeur, RD Wilson, MT Ciannelli, L AF Brodeur, RD Wilson, MT Ciannelli, L TI Spatial and temporal variability in feeding and condition of age-0 walleye pollock (Theragra chalcogramma) in frontal regions of the Bering Sea SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Symposium on Recruitment Dynamics of Exploited Marine Populations - Physical-Biological Interactions CY SEP, 1997 CL BALTIMORE, MD SP ICES DE condition; daily ration; food habits; Walleye pollock ID GULF-OF-ALASKA; PRIBILOF-ISLANDS; FISH; HADDOCK; CANNIBALISM; WATERS; SHELF; COD AB Dietary composition, feeding intensity, and condition index of age-0 walleye pollock (Theragra chalcogramma) were examined for variations related to time of day, location, size of predator, and year. Stomach contents of pollock collected at a hydrographic Bent near the Pribilof Islands during September 1994 through 1996 were compared with those collected on either side of the front. Diets were dominated in all regions by small zooplankton, mainly copepods, pteropods, euphausiids, and chaetognaths, but fish and some epibenthic crustaceans were also consumed. Copepods and pteropods dominated the diet in all years and areas by number, but the diet was more mixed by weight with chaetognaths, euphausiids, and fish (small pollock) also being important. No significant diel differences in the gravimetric composition of major prey taxa were noted. Stomach fullness was highly variable by year and habitat and no significant differences were observed. Stomach fullness peaked at around sunset for fish <50 mm and at night for the larger fish, implying that Feeding chronology changed with ontogeny. Pollock condition factor (Fulton's K) varied from 0.45 to 1.20 (mean=0.77; s.d.=0.09). Year was not found to be an important factor relating to condition, although location with respect to the front was important with offshore fish having a significantly higher condition than those fish found inshore of the front.; (C) 2000 International Council for the Exploration of the Sea. C1 Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP NW Fisheries Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM rick.brodeur@noaa.gov NR 36 TC 47 Z9 49 U1 1 U2 11 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1054-3139 EI 1095-9289 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 256 EP 264 DI 10.1006/jmsc.1999.0525 PG 9 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900009 ER PT J AU Lang, GM Brodeur, RD Napp, JM Schabetsberger, R AF Lang, GM Brodeur, RD Napp, JM Schabetsberger, R TI Variation in groundfish predation on juvenile walleye pollock relative to hydrographic structure near the Pribilof Islands, Alaska SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Symposium on Recruitment Dynamics of Exploited Marine Populations - Physical-Biological Interactions CY SEP, 1997 CL BALTIMORE, MD SP ICES DE Bering Sea; cannibalism; predation; tidal fronts; walleye pollock ID EASTERN BERING SEA; THERAGRA-CHALCOGRAMMA; PACIFIC HAKE; CANNIBALISM; ZOOPLANKTON; SELECTION; FISHES; SHELF; NETS AB Walleye pollock (Theragra chalcogramma) are an important forage fish in the eastern Bering Sea ecosystem. As part of an ongoing study of the processes affecting juvenile walleye pollock recruitment in the eastern Bering Sea, a concentrated effort has been focused on the hydrographic fronts near the Pribilof Islands, Alaska, as important nursery areas for these juveniles. Diel variation in the consumption of age-0 pollock by arrowtooth flounder (Atherethes stomias) was examined from a series of collections at a station at the tidal front located north of St Paul Island, Alaska. Age-0 pollock were the primary prey of arrowtooth flounder throughout the day, but they were least digested in the late day, indicating a diurnal feeding pattern. A similar diurnal pattern was not seen in the vertical distribution of age-0 pollock, suggesting that the feeding pattern exhibited by arrowtooth flounder was based on their diel migratory behavior. Lengths of age-0 pollock consumed by arrowtooth flounder were similar to those sampled with midwater trawls. Walleye pollock cannibalism was examined along a transect that included samples collected at the front and offshore of the front. Age-0 fish were the primary prey (by weight) at all locations. Adjacent cohort cannibalism was prevalent (age-0 pollock were 79% of the diet by weight) at the frontal region. Estimates of age-0 pollock cannibalism rates were highest at the front for age-1 pollock and offshore for the adults. Prey selectivity analysis indicated that age-0 pollock were more highly selected offshore than at the front. (C) 2000 International Council for the Exploration of the Sea. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Lang, GM (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM geoff.lang@noaa.gov NR 35 TC 32 Z9 32 U1 2 U2 8 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 265 EP 271 DI 10.1006/jmsc.1999.0600 PG 7 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900010 ER PT J AU Wespestad, VG Fritz, LW Ingraham, WJ Megrey, BA AF Wespestad, VG Fritz, LW Ingraham, WJ Megrey, BA TI On relationships between cannibalism, climate variability, physical transport, and recruitment success of Bering Sea walleye pollock (Theragra chalcogramma) SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Symposium on Recruitment Dynamics of Exploited Marine Populations - Physical-Biological Interactions CY SEP, 1997 CL BALTIMORE, MARYLAND SP ICES DE walleye pollock; Bering Sea; recruitment; cannibalism; climate; ocean currents AB Walleye pollock (Theragra chalcogramma) is the single most abundant fish species in the Bering Sea and comprises the bulk of the commercial catch. Juvenile pollock are an important forage fish for older pollock, other fish, marine mammals, and birds. We examine the interaction between cannibalism, climate variability, and related patterns in physical transport. Our analysis of adult and juvenile pollock abundance and distribution time series, ocean current modelling studies, and information on climate variability indicates that cannibalism is a major determinant of interannual recruitment variability. In turn, the intensity of cannibalism appears to be dependent on the degree of spatial separation of adults and juveniles. Strong year classes occur when juvenile pollock are transported inshore and away from adults in spring - conditions typical of warm years. In cold years, transport is reduced and juveniles remain on the outer shelf in proximity to adults. Go-occurring distribution patterns of adults and juveniles resulting from these conditions lead to potentially increased cannibalism and subsequent weak year classes. (C) 2000 International Council for the Exploration of the Sea. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Wespestad, VG (reprint author), Alaska Fisheries Ctr, 7600 Sandpoint G18 NE, Seattle, WA 98036 USA. NR 24 TC 71 Z9 74 U1 0 U2 11 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 272 EP 278 DI 10.1006/jmsc.2000.0640 PG 7 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900011 ER PT J AU Hollowed, AB Ianelli, JN Livingston, PA AF Hollowed, AB Ianelli, JN Livingston, PA TI Including predation mortality in stock assessments: a case study for Gulf of Alaska walleye pollock SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Symposium on Recruitment Dynamics of Exploited Marine Populations - Physical-Biological Interactions CY SEP, 1997 CL BALTIMORE, MARYLAND SP ICES DE predation; stock assessment; uncertainty; walleye pollock ID STELLER SEA LIONS; NATURAL MORTALITY; THERAGRA-CHALCOGRAMMA; FORAGING BEHAVIOR; MULTISPECIES VPA; COHORT ANALYSIS; AGE DATA; CATCH; FISH; ERRORS AB A separable catch-age stock assessment model that accommodates predation mortality. is applied to the Gulf of Alaska walleye pollock (Theragra chalcogramma) assessment. Three predators are incorporated in the model: arrowtooth flounder (Atheresthes stomias), Pacific halibut (Hippoglossus stenolepis), and Steller sea lion (Eumetopias jubatus). The effect of these predators is examined by defining the predation mortality as a type of fishery. The model is used to quantify changes in the relative fit to the survey, fishery, and predator data when the assumption of constant natural mortality is relaxed. Specifically, we examine the effect of assumptions regarding the functional feeding response, residual naturaly mortality, and uncertainty in predator biomass on stock assessment. Total natural mortality rates (including predation) tended to be higher than estimated from life history characteristics of the stock. Models that did not account for uncertainty in natural mortality underestimated uncertainty in current stock biomass by as much as 20%. Our results indicate that independent estimates of survey selectivity, additional food habits data, and estimates of the feeding responses of predators to different prey densities are all needed to improve our ability to develop stock assessment models that address ecosystem concerns. (C) 2000 International Council for the Exploration of the Sea. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Hollowed, AB (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 76 TC 61 Z9 64 U1 3 U2 15 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 279 EP 293 DI 10.1006/jmsc.1999.0637 PG 15 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900012 ER PT J AU Livingston, PA Jurado-Molina, J AF Livingston, PA Jurado-Molina, J TI A multispecies virtual population analysis of the eastern Bering Sea SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Symposium on Recruitment Dynamics of Exploited Marine Populations - Physical-Biological Interactions CY SEP, 1997 CL BALTIMORE, MARYLAND SP ICES DE multispecies model; predation; recruitment ID POLLOCK THERAGRA-CHALCOGRAMMA; BALTIC COD; RECRUITMENT AB The eastern Bering Sea shelf supports a large biomass of several groundfish populations, particularly walleye pollock (Theragra chalcogramma). The main trophic interactions between dominant groundfish populations in this region involve walleye pollock as prey. A multispecies virtual population analysis model (MSVPA) covering the period 1979-1995 has been parameterized for the eastern Bering Sea in order to move closer to providing multispecies management advice for this region. The MSVPA model is based on extensive diet data from 70 predator/prey/year/quarter combinations and currently includes the following species as predators: walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus), Greenland turbot (Reinhardtius hippoglossoides), yellowfin sole (Pleuronectes asper), arrowtooth Bounder Atheresthes stomias, and northern fur seal (Callorhinus ursinus). Arrowtooth Bounder and northern fur seals are entered as "other predators", which means that population and mortality estimates are not directly made for these species. Estimates of their consumption rates, diet, and population abundance are input, however, so that their predation on prey species in the model can be calculated. Prey species are walleye pollock, Pacific cod, Greenland turbot, yellowfin sole, rock sole (Lepidopsetta bilineatus), and Pacific herring (Clupea pallasi). Results show that large numbers of walleye pollock, particularly age-0 and age-1 fish, are consumed and cannibalism by adult pollock constitutes the largest source of predation mortality for age-0 fish. predation plays an important role in explaining the recruitment dynamics of pollock. Further advances may be made when these estimates are linked to models that examine the effect of climate-related factors influencing larval survival. (C) 2000 International Council for the Exploration of the Sea. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. RP Livingston, PA (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 26 TC 53 Z9 57 U1 1 U2 5 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 294 EP 299 DI 10.1006/jmsc.1999.0524 PG 6 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900013 ER PT J AU Friedland, KD Hansen, LP Dunkley, DA MacLean, JC AF Friedland, KD Hansen, LP Dunkley, DA MacLean, JC TI Linkage between ocean climate, post-smolt growth, and survival of Atlantic salmon (Salmo salar L.) in the North Sea area SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Symposium on Recruitment Dynamics of Exploited Marine Populations - Physical-Biological Interactions CY SEP, 1997 CL BALTIMORE, MARYLAND SP ICES DE Atlantic salmon; growth; post-smolt survival; recruitment; sea surface temperature; thermal habitat ID ONCORHYNCHUS-KISUTCH; CHINOOK SALMON; BRITISH-COLUMBIA; ICELANDIC STOCKS; MARINE SURVIVAL; SOCKEYE-SALMON; JUVENILE PINK; AGE; MATURITY; TEMPERATURE AB We examined two long-term tagging studies with wild salmon stocks in the North Sea area. The salmon stocks, the Figgjo in southern Norway and the North Esk in eastern Scotland, reside in relatively un-impacted rivers that continue to sustain healthy runs of salmon. The return rates for one seawinter fish (ISW), the predominant age at maturity for both stocks, were highly correlated. An analysis of sea surface temperature distributions for periods of high versus low return rate showed that when low sea surface temperatures dominate the North Sea and southern coast of Norway during May, salmon survival has been poor. Conversely, when high sea surface temperatures extend northward along the Norwegian coast during May, survival has been good. Ocean conditions can be further related to the recruitment process through growth studies for the North Esk stock. Post-smelt growth increments for returning ISW fish showed that enhanced growth was associated with years during which temperature conditions were favorable, which in turn resulted in higher survival rates. The implicit linkage between growth and survival suggests that growth-mediated predation is the dominant source of recruitment variability. Mechanisms by which ocean climate may affect post-smelt growth are discussed. (C) 2000 international Council for the Exploration of the Sea. C1 Univ Massachusetts, CMER Program, NOAA, Amherst, MA 01003 USA. Norwegian Inst Nat Res, N-0105 Oslo, Norway. Salmon & Freshwater Fisheries, Edinburgh EH14 1TY, Midlothian, Scotland. Freshwater Fisheries Lab, Field Stn, Montrose DD10 8DL, Angus, Scotland. RP Friedland, KD (reprint author), Univ Massachusetts, CMER Program, NOAA, Blaisdell House, Amherst, MA 01003 USA. NR 54 TC 126 Z9 127 U1 3 U2 29 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD APR PY 2000 VL 57 IS 2 BP 419 EP 429 DI 10.1006/jmsc.1999.0639 PG 11 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 323DE UT WOS:000087548900026 ER PT J AU Corner, MD Liebeherr, J Golmie, N Bisdikian, C Su, DH AF Corner, MD Liebeherr, J Golmie, N Bisdikian, C Su, DH TI A priority scheme for the IEEE 802.14 MAC protocol for hybrid fiber-coax networks SO IEEE-ACM TRANSACTIONS ON NETWORKING LA English DT Article DE local area networks; quality-of-service ID ACCESS; ALGORITHMS; SERVICES; SYSTEMS AB In order to support quality-of-service (QoS) for real-time data communications such as voice, video and interactive services, multiaccess networks must provide an effective priority mechanism. The context of this work is the IEEE 802.14 standard for hybrid fiber coaxial (HFC) networks which has a shared upstream channel for transmissions from stations to the headend. This work presents a multilevel priority collision resolution scheme, which separates and resolves collisions between stations in a priority order, thereby, achieving the capability for preemptive priorities, We present a set of simulation scenarios which show the robustness and efficiency of the scheme, such as its ability to isolate higher priority traffic from lower priorities and to provide quick access to high-priority requests. In March 1998, a framework for handling priorities in the collision resolution process, which adopts a semantics similar to the semantics of our scheme, was included in the 802.14 standard. C1 Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA. Univ Virginia, Dept Comp Sci, Charlottesville, VA 22903 USA. NIST, Gaithersburg, MD 20899 USA. IBM, TJ Watson Res Ctr, Hawthorne, NY 10523 USA. RP Corner, MD (reprint author), Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA. NR 22 TC 18 Z9 18 U1 3 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1063-6692 J9 IEEE ACM T NETWORK JI IEEE-ACM Trans. Netw. PD APR PY 2000 VL 8 IS 2 BP 200 EP 211 DI 10.1109/90.842142 PG 12 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 312ZX UT WOS:000086974800006 ER PT J AU Little, BE Chu, ST AF Little, BE Chu, ST TI Theory of polarization rotation and conversion in vertically coupled microresonators SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE polarization rotation; resonators; wavelength filter; microcavity ID WAVE-GUIDES; MODE THEORY AB Two orthogonally polarized waveguide modes cap exchange power through an intermediate level, if the polarization state of that level is tilted with respect to the polarization states of the waveguide, Microrings with modest sidewall angles support such tilted modes. Ultracompact, wavelength selective polarization rotators might be achieved. Simple analytic expressions are derived for polarization rotation by vertically-coupled resonators in terms of geometrical factors. C1 Univ Maryland, Lab Phys Sci, College Pk, MD 20740 USA. MIT, Elect Res Lab, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Little, BE (reprint author), Univ Maryland, Lab Phys Sci, College Pk, MD 20740 USA. RI Chu, Sai /D-3312-2014; OI CHU, Sai Tak /0000-0001-8263-8507 NR 15 TC 38 Z9 38 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD APR PY 2000 VL 12 IS 4 BP 401 EP 403 DI 10.1109/68.839032 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 306XW UT WOS:000086624800009 ER PT J AU Subbarao, MW Hughes, BL AF Subbarao, MW Hughes, BL TI Optimal transmission ranges and code rates for frequency-hop packet radio networks SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article; Proceedings Paper CT 31st Annual Conference on Information Sciences and Systems CY MAR 19-21, 1997 CL JOHNS HOPKINS UNIV, BALTIMORE, MARYLAND HO JOHNS HOPKINS UNIV DE frequency-hopping modulation; optimum code rates; optimum transmission ranges; spectral efficiency; spread-spectrum ID SPECTRUM; PERFORMANCE; SYSTEMS AB We consider a frequency-hopping multihop packet radio; network using M-ary frequency-shift keying modulation in a Rayleigh fading environment. Each node transmits packets using gn extended (n, k)Reed-Solomon code and the slotted ALOHA channel-access protocol. For this network, we determine the optimum transmission range, optimum code rate, and optimum Slotted ALOHA transmission probability to be used by each node in the network, Tradeoffs in choosing the transmission range and code rate, and the spectral efficiency of the network are captured in a; new performance measure, information efficiency, which is analogous to expected forward progress. Maximizing information efficiency yields the optimum desired network parameters. C1 Johns Hopkins Univ, Dept Elect & Comp Engn, Baltimore, MD 21218 USA. RP Subbarao, MW (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 17 TC 31 Z9 33 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 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD APR PY 2000 VL 48 IS 4 BP 670 EP 678 DI 10.1109/26.843134 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 314WU UT WOS:000087081200019 ER PT J AU Elmquist, RE AF Elmquist, RE TI Calculable coaxial resistors for precision measurements SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE impedance measurement; measurement standards; resistance measurement; skin effect; thermoelectricity ID QUANTIZED HALL RESISTANCE; AC AB Coaxial straight-wire resistors have been constructed with the purpose of improving comparisons between resistors, capacitors, and inductors in the audio-frequency range. The design is based on the principle that a coaxial line with a cylindrical shield can be described by relatively simple equations for the real and imaginary parts of the impedance. The resistors, with values at and above 100 Ohm mill be used as transfer standards for characterization of the frequency dependence of standard resistors and of the quantum Hall resistance in the audio frequency range. C1 NIST, US Dept Commerce, Technol Adm,Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. RP Elmquist, RE (reprint author), NIST, US Dept Commerce, Technol Adm,Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. NR 12 TC 9 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 2000 VL 49 IS 2 BP 210 EP 215 DI 10.1109/19.843051 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 319EK UT WOS:000087328400001 ER PT J AU Koffman, AD Avramov-Zamurovic, S Waltrip, BC Oldham, NM AF Koffman, AD Avramov-Zamurovic, S Waltrip, BC Oldham, NM TI Uncertainty analysis for four terminal-pair capacitance and dissipation factor characterization at 1 and 10 MHz SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE capacitance; dissipation factor; four terminal pair; impedance; precision measurements; uncertainty analysis AB The Electricity Division at the Nationals Institute of Standards and Technology (NIST, formerly NBS) has developed the capability to characterize capacitance and dissipation factor for four terminal-pair (4TP) air dielectric capacitors at frequencies from 1 kHz to 10 MHz, The method, based on work by Cutkosy and Jones of NBS and recent developments by Hewlett-Packard Japan, involves single-port network analyzer impedance measurements at frequencies from 40 MHz to 200 MHz and capacitance measurements using a precision 1 kHz capacitance meter, A mathematical regression algorithm is used to extrapolate inductance and resistance measurements from the network analyzer down to 1 kHz in order to predict capacitance and dissipation factor from 1 kHz to 10 MHz. A comprehensive uncertainty analysis for the procedure is presented. C1 NIST, Div Elect, Gaithersburg, MD 20899 USA. USN Acad, Dept Syst Engn, Annapolis, MD 21402 USA. RP Koffman, AD (reprint author), NIST, Div Elect, Gaithersburg, MD 20899 USA. NR 12 TC 9 Z9 9 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 2000 VL 49 IS 2 BP 346 EP 348 DI 10.1109/19.843076 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 319EK UT WOS:000087328400026 ER PT J AU Avramov-Zamurovic, S Koffman, AD Oldham, NM Waltrip, BC AF Avramov-Zamurovic, S Koffman, AD Oldham, NM Waltrip, BC TI The sensitivity of a method to predict a capacitor's frequency characteristic SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE capacitance; dissipation factor; four terminal-pair capacitor; high frequency; impedance; precision measurements; sensitivity analysis AB A joint effort between the U.S. Naval Academy and the National Institute of Standard and Technology (NIST) resulted in the development of a method to characterize the capacitance and dissipation factor of a set of commercial standard four terminal-pair (4TP) capacitors, The method depends on network analyzer impedance measurements at high frequencies (40 MH-200 MHz) and a regression of these measurements down to the frequency range of 10 MHz-1 kHz. This paper provides an analysis of the sensitivity of the regression parameters and the high-frequency impedance measurements. C1 USN Acad, Annapolis, MD 21402 USA. US Dept Commerce, Technol Adm, Elect & Elect Engn Lab, Natl Inst Stand & Technol,Elect Div, Gaithersburg, MD 20899 USA. RP Avramov-Zamurovic, S (reprint author), USN Acad, Annapolis, MD 21402 USA. NR 9 TC 14 Z9 16 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 2000 VL 49 IS 2 BP 398 EP 404 DI 10.1109/19.843085 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 319EK UT WOS:000087328400035 ER PT J AU MacDonald, ME Alexanian, A York, RA Popovic, Z Grossman, EN AF MacDonald, ME Alexanian, A York, RA Popovic, Z Grossman, EN TI Spectral transmittance of lossy printed resonant-grid terahertz bandpass filters SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE FSS; spatial filters; terahertz AB In this paper, we present terahertz bandpass tilters composed of resonant arrays of crossed slots in lossy metal films deposited on dielectric membranes. The filters exhibit insertion loss as low as 1.9 dB at room temperature and 1.2 dB at 77 K at a center frequency of 2.2 THz, It is found that the dielectric substrate introduces a downward shift in frequency not predicted by standard mean dielectric-constant approximations. This shift is proportional to the permittivity and thickness of the substrate, and is accurately modeled for polyester, fused quartz and silicon substrates using a finite-difference time-domain (FDTD) model. It is also found that the insertion loss and Q-factors of the filters vary with the product of the thickness and conductivity of the metal film for lead and gold films, even in cases when the thickness is several skin depths at the center frequency. The FDTD theory presented here accounts for some of the conductor losses. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. RP MacDonald, ME (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 16 TC 48 Z9 52 U1 0 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 2000 VL 48 IS 4 BP 712 EP 718 DI 10.1109/22.841963 PN 2 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 310FN UT WOS:000086816000013 ER PT J AU Hofman, GJ Peterson, RJ Gelderloos, CJ Ristinen, RA Nelson, ME Thompson, A Ziegler, JF Mullfeld, H AF Hofman, GJ Peterson, RJ Gelderloos, CJ Ristinen, RA Nelson, ME Thompson, A Ziegler, JF Mullfeld, H TI Light-hadron induced SER and scaling relations for 16-and 64-Mb DRAMS SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article DE circuit design; hadrons; memory testing; particle beams; soft error rates ID REACTION CROSS-SECTIONS; SCATTERING; NUCLEI; PIONS; CHIPS AB We report on soft error rates (SER) of 16 and 64 Mb dynamic memory chips induced by three types of elementary particles, neutrons, protons, and pions, with emphasis on results obtained with pion beams. Significant SER differences, up to a factor 1000, are seen between various manufacturers and cell technologies. We discuss reaction mechanisms and by comparing SER rates to nuclear reaction cross sections present guidelines for predicting failure rates. C1 Univ Colorado, Phys Nucl Lab, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hofman, GJ (reprint author), Univ Colorado, Phys Nucl Lab, Boulder, CO 80309 USA. NR 21 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD APR PY 2000 VL 47 IS 2 BP 403 EP 407 DI 10.1109/23.846273 PN 2 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 321VE UT WOS:000087474700002 ER PT J AU Vasconcellos, ECC Zerbetto, SC Zink, LR Evenson, KM AF Vasconcellos, ECC Zerbetto, SC Zink, LR Evenson, KM TI Optically pumped far-infrared laser lines of methanol isotopomers: (CD3OH)-C-12, (CH3OD)-C-12, and (CH2DOH)-C-12 SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE (CD3OH)-C-12; (CH3OD)-C-12; (CH2DOH)-C-12; new far-infrared laser lines; optically pumped far-infrared laser; laser frequencies; relative intensity; relative polarization; pump-frequency offset AB Twenty-seven new FIR, far-infrared, laser lines from the isotopomers of methanol: (CD3OH)-C-12, (CH3OD)-C-12, and (CH2DOH)-C-12 were obtained by optically pumping the molecules with an efficient cw CO2 laser. The CO(2)laser provided pumping from regular, sequence, and hot-band CO2 laser transitions. The 2 m long far-infrared cavity was a metal-dielectric waveguide closed by two, hat end mirrors. Several short-wavelength (below 100 mu m) lines were observed. The frequencies of 28 laser lines observed in this cavity (including new lines and already known lines) were measured with a fractional uncertainty limited by the fractional resetability of the far-infrared laser cavity, of 2 parts in 10(7). C1 Univ Estadual Campinas, Dept Elect Quant, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Vasconcellos, ECC (reprint author), Univ Estadual Campinas, Dept Elect Quant, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil. RI Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 4 TC 11 Z9 11 U1 0 U2 2 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD APR PY 2000 VL 21 IS 4 BP 477 EP 483 DI 10.1023/A:1006667300438 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 301TJ UT WOS:000086326100001 ER PT J AU Wolfe, DE Gutman, SI AF Wolfe, DE Gutman, SI TI Developing an operational, surface-based, GPS, water vapor observing system for NOAA: Network design and results SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID GLOBAL POSITIONING SYSTEM; PRECIPITABLE WATER; METEOROLOGY AB The need for a reliable, low-cost observing system to measure water vapor in the atmosphere is incontrovertible. Experiments have shown the potential for using Global Positioning System (GPS) receivers to measure total precipitable water vapor accurately at different locations and times of year and under all weather conditions. The National Oceanic and Atmospheric Administrations's (NOAA) Forecast Systems Laboratory (FSL) and Environmental Technology Laboratory (ETL), in collaboration with the University NAVSTAR Consortium, University of Hawaii, Scripps Institution of Oceanography, and NOAA's National Geodetic Survey (NGS) Laboratory, are addressing this need by developing a ground-based water vapor observing system based on the measurement of GPS signal delays caused by water vapor in the atmosphere. The NOAA GPS Integrated Precipitable Water Vapor (NOAA GPS-IPW) network currently has 35 continuously operating stations and is expected to expand into a 200-station demonstration network by 2004. This paper describes the major accomplishments of the project since its inception in 1994. Results from the analysis of the effect of satellite orbit accuracies on IPW accuracy are discussed. Several comparisons with collocated remote and in situ measurements, including radiosondes and ground- and space-based radiometers are shown. Results from preliminary model runs using the FSL Forecast Research Division's Mesoscale Analysis and Prediction System (MAPS) model are presented. This work shows the feasibility of an operational system using GPS to continuously monitor atmospheric water vapor in near-real time with accuracies (< 1.5 cm) comparable to radiosondes and water vapor radiometers. C1 NOAA, ERL, ETL, Boulder, CO 80303 USA. NOAA, Forecast Syst Lab, Boulder, CO USA. RP Wolfe, DE (reprint author), NOAA, ERL, ETL, R-E-ET4,325 Broadway, Boulder, CO 80303 USA. NR 30 TC 68 Z9 72 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2000 VL 17 IS 4 BP 426 EP 440 DI 10.1175/1520-0426(2000)017<0426:DAOSBG>2.0.CO;2 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 307VN UT WOS:000086675000005 ER PT J AU Delene, DJ Deshler, T AF Delene, DJ Deshler, T TI Calibration of a photometric cloud condensation nucleus counter designed for deployment on a balloon package SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SULFATE AEROSOLS; CLIMATE-CHANGE AB The importance of atmospheric aerosols in understanding global climate changes has renewed interest in measurements of cloud condensation nuclei (CCN). To obtain high-resolution (125 m) vertical profiles of CCN number concentration, a balloon-borne instrument was developed. The instrument deduces the CCN concentration from measurements of laser light scattered by water droplets that condense on CCN within a static thermal-gradient diffusion chamber. The amount of light scattering is linearly proportional to the number of droplets within the diffusion chamber. Correlating the number of droplets within the sample volume with the amount of light scattered by the droplets provides the calibration constant that relates scattered light to CCN concentration. The calibration was tested by comparisons between the CCN counter and a condensation nuclei counter when sampling monodisperse aerosol larger than the CCN counter's critical activation size. The calibration constant depends on supersaturation, and depends slightly on the size of CCN that activate to form droplets. For dry NaCl aerosol between 35 and 160 nm, the calibration constant varies by less than 10% at 1% supersaturation. Calibration on ambient atmospheric aerosol is similar to calibration on laboratory-generated polydisperse NaCl aerosol, which indicates that the laboratory calibration can be applied to field measurements. During held and laboratory measurements, the rime required for the activation and growth of droplets within the diffusion chamber is similar. Overall, the uncertainty of the calibration constant for the balloon-borne CCN counter is approximately 10% at 1% supersaturation. C1 Univ Wyoming, Dept Atmospher Sci, Laramie, WY 82071 USA. RP Delene, DJ (reprint author), NOAA, Climate Monitoring & Diagnost Lab, R-E-CG1,325 Broadway, Boulder, CO 80303 USA. NR 25 TC 21 Z9 22 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2000 VL 17 IS 4 BP 459 EP 467 DI 10.1175/1520-0426(2000)017<0459:COAPCC>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 307VN UT WOS:000086675000007 ER PT J AU Lakshmanan, V AF Lakshmanan, V TI Speeding up a large-scale filter SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID PRECIPITATION; RADAR AB Wolfson et al. introduced a storm tracking algorithm, called the Growth and Decay Storm Tracker, in which the large-scale features were extracted from radar data fields by using on elliptical tilter. The elliptical filter as introduced was computationally too expensive to be performed in real time. In this paper, it is shown that although the elliptical filter is nonlinear, it can be decomposed into two parts, one of which is, under some simplifying assumptions, linear and shift-invariant. The linear component can be accelerated using fast algorithms available ro compute the digital Fourier transform (DFT). Furthermore. it is shown that the nonlinear part can be written as an update equation, thus reducing the amount of computer memory required. With these improvements to the basic large-scale filtering technique, this paper reports that the large-scale filtering can be done 1-2 orders of magnitude faster. The improvement makes it possible to use the large-scale filtering technique in situations where the computational time and memory requirements have been prohibitive. C1 US Dept Commerce, Natl Severe Storms Lab, Stormscale Res & Applicat Div, Norman, OK 73069 USA. Univ Oklahoma, Norman, OK 73019 USA. RP Lakshmanan, V (reprint author), US Dept Commerce, Natl Severe Storms Lab, Stormscale Res & Applicat Div, 1313 Halley Circle, Norman, OK 73069 USA. NR 7 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2000 VL 17 IS 4 BP 468 EP 473 DI 10.1175/1520-0426(2000)017<0468:SUALSF>2.0.CO;2 PG 6 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 307VN UT WOS:000086675000008 ER PT J AU Maes, C Behringer, D Reynolds, RW Ji, M AF Maes, C Behringer, D Reynolds, RW Ji, M TI Retrospective analysis of the salinity variability in the western Tropical Pacific Ocean using an indirect minimization approach SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID EQUATORIAL PACIFIC; SEA-LEVEL; DATA ASSIMILATION; NORTH-ATLANTIC; CIRCULATION; TRANSPORTS; MESOSCALE; SURFACE AB Empirical orthogonal functions of the combined variability of temperature and salinity have been used as basis functions for the indirect reconstruction of salinity from observations of temperature alone. The method employs a weighted least squares procedure that minimizes the misfit between the reconstructed temperature and the observed temperature, but also constrains the variability of the reconstructed salinity to remain within specified bounds. The method has been tested by fitting to temperature profiles from the Tropical Atmosphere Ocean array along 165 degrees E in the western equatorial Pacific Ocean (8 degrees N-8 degrees S) for the 1986-97 period. Comparisons of the reconstructed salinity field with sea surface salinity and conductivity-temperature-depth data and of the reconstructed dynamic height with TOPEX/Poseidon observations of sea level demonstrate the reliability of the method. The reconstructed data successfully capture the upper-ocean variability at annual to ENSO timescales. The impact of neglecting salinity variability on the dynamic height anomaly in the western tropical Pacific Ocean is addressed. C1 Natl Ctr Environm Predict, Climate Modeling Branch, Camp Springs, MD USA. RP Maes, C (reprint author), SCEM, PREVI, MAR, 42 Ave Coriolis, F-31057 Toulouse, France. RI maes, christophe/L-4049-2015 OI maes, christophe/0000-0001-6532-7141 NR 36 TC 27 Z9 31 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2000 VL 17 IS 4 BP 512 EP 524 DI 10.1175/1520-0426(2000)017<0512:RAOTSV>2.0.CO;2 PG 13 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 307VN UT WOS:000086675000012 ER PT J AU Winton, M AF Winton, M TI A reformulated three-layer sea ice model SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID VARIABILITY; ATMOSPHERE; CLIMATE AB A model is presented that provides an efficient approximation to sea ice thermodynamics for climate studies. Semtner's three-layer framework is used, bur the brine content of the upper ice is represented with a variable heat capacity as is done in more physically based models. A noniterative fully implicit time-stepping scheme is used for calculation of ice temperature. The results of the new model are compared to those of Semtner's original model. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Winton, M (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 10 TC 154 Z9 171 U1 0 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD APR PY 2000 VL 17 IS 4 BP 525 EP 531 DI 10.1175/1520-0426(2000)017<0525:ARTLSI>2.0.CO;2 PG 7 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 307VN UT WOS:000086675000013 ER PT J AU Dori, Y Bianco-Peled, H Satija, SK Fields, GB McCarthy, JB Tirrell, M AF Dori, Y Bianco-Peled, H Satija, SK Fields, GB McCarthy, JB Tirrell, M TI Ligand accessibility as means to control cell response to bioactive bilayer membranes SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE Langmuir-Blodgett; cell adhesion; poly(ethylene glycol); neutron reflectivity; peptide amphiphile; atomic force microscopy ID STERICALLY STABILIZED LIPOSOMES; PROTEIN MOLECULAR ARCHITECTURE; SELF-ASSEMBLED MONOLAYERS; SURFACE INTERACTIONS; POLYETHYLENE OXIDE; FIBROBLASTS; TOPOGRAPHY; ADSORPTION; CONSTRUCTION; AMPHIPHILES AB We report a new method to create a biofunctional surface in which the accessibility of a ligand is used as a means to influence the cell behavior. Supported bioactive bilayer membranes were created by Langmuir-Blodgett (LB) deposition of either a pure poly(ethylene glycol) (PEG) lipid, having PEG head groups of various lengths, or 50 mol % binary mixtures of a PEG lipid and a novel collagen-like peptide amphiphile on a hydrophobic surface. The peptide amphiphile contains a peptide synthetically lipidated by covalent linkage to hydrophobic dialkyl tails. The amphiphile head group lengths were determined using neutron reflectivity. Cell adhesion and spreading assays showed that the cell, response to the membranes depends on the length difference between head groups of the membrane components. Cells adhere and spread on mixtures of the peptide amphiphile with the PEG lipids having PEG chains of 120 and 750 molecular weight (MW). In contrast, cells adhered but did not spread on the mixture containing the 2000 MW PEG. Cells did not adhere to any of the pure PEG lipid membranes or to the mixture containing the 5000 MW PEG. Selective masking of a ligand on a surface is one method of controlling the surface bioactivity. (C) 2000 John Wiley & Sons, Inc. C1 Univ Minnesota, Dept Chem Engn & Mat, Minneapolis, MN 55455 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Florida Atlantic Univ, Dept Chem & Biochem, Boca Raton, FL 33431 USA. Univ Minnesota, Dept Lab Med & Pathol, Minneapolis, MN 55455 USA. RP Tirrell, M (reprint author), Univ Minnesota, Dept Chem Engn & Mat, Minneapolis, MN 55455 USA. FU NHLBI NIH HHS [R01-HL62427-01] NR 32 TC 66 Z9 68 U1 0 U2 21 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD APR PY 2000 VL 50 IS 1 BP 75 EP 81 DI 10.1002/(SICI)1097-4636(200004)50:1<75::AID-JBM11>3.0.CO;2-A PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 274NP UT WOS:000084772200011 PM 10644966 ER PT J AU O'Hare, PAG Watling, K Hope, GA AF O'Hare, PAG Watling, K Hope, GA TI Thermodynamic properties of vanadium silicides II. Standard molar enthalpy of formation Delta H-f(m)0 (298.15 K) and reassessed thermodynamic properties of trivanadium monosilicide (V3Si) SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE vanadium silicide; fluorine calorimetry; enthalpy of formation; thermodynamic properties ID TEMPERATURE 298.15-K; SILICON SYSTEM; FLUORINE; COMBUSTION; CALORIMETRY; DISILICIDE; ENERGY AB Fluorine bomb combustion calorimetric measurements of the energy of the reaction: V3Si(cr) + (19/2)F-2(g) = 3VF(5)(g) + SiF4(g), have given a value of -(163.3 +/- 6.9) kJ . mol(-1) for the standard molar enthalpy of formation Delta(f)H(m)(0) (V3Si, cr) at T = 298.15 K and p(0) = 101.325 kPa. This result is compared with others from the literature. A table is also given of the reassessed conventional chemical thermodynamic properties of V3Si from T = 298.15 K to T = 1700 K. (C) 2000 Academic Press. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Griffith Univ, Nathan, Qld 4111, Australia. RP O'Hare, PAG (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Hope, Gregory/A-7556-2008 OI Hope, Gregory/0000-0003-2694-3456 NR 36 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD APR PY 2000 VL 32 IS 4 BP 427 EP 437 DI 10.1006/jcht.1999.0612 PG 11 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 299UG UT WOS:000086215800001 ER PT J AU Lim, HJ DeMattei, RC Feigelson, RS Rochford, K AF Lim, HJ DeMattei, RC Feigelson, RS Rochford, K TI Striations in YIG fibers grown by the laser-heated pedestal method SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE YIG; float-zone method; traveling solvent zone method; solution growth; laser-heated pedestal growth; light scattering tomography ID FLOATING-ZONE METHOD; YTTRIUM-IRON-GARNET; CRYSTALS AB Yttrium iron garnet (YIG) single-crystal fibers of nominal composition Y3Fe5O12 were grown by the laser-heated pedestal growth technique, a miniaturized float-zone process. YIG fibers in diameters ranging from 100 to 740 mu m were grown at various rates and conditions, and analyzed by X-ray diffraction, electron microprobe, IR-VIS spectroscopy, and light scattering tomography. Infrared transparent YIG fibers were grown at rates below 10 mm/h in air. The transparency of the fibers was more dependent on the growth rate than on the stability of the molten zone. Some striations and surface ridges containig a Fe-rich composition were observed at all growth rates. Light scattering tomography studies revealed the presence of inclusions in some YIG fibers. Their size, density, composition and distribution depended on the growth conditions and molten zone stability. At growth rates below 10 mm/h, these defects and also the iron-oxide inclusions, which act as IR scattering centers, were significantly reduced. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Mat Res Ctr, Stanford, CA 94305 USA. Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Feigelson, RS (reprint author), Stanford Univ, Mat Res Ctr, 111 McCullough Bldg, Stanford, CA 94305 USA. NR 21 TC 9 Z9 9 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 2000 VL 212 IS 1-2 BP 191 EP 203 DI 10.1016/S0022-0248(00)00017-8 PG 13 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 307WX UT WOS:000086678100028 ER PT J AU Warren, JA Kobayashi, R Carter, WC AF Warren, JA Kobayashi, R Carter, WC TI Modeling grain boundaries using a phase-field technique SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 11th American Conference on Crystal Growth and Epitaxy CY AUG 01-06, 1999 CL TUCSON, ARIZONA SP Assoc Crystal Growth, NASA, Div Micrograv Sci & Applicat, Adv Ceram Corp, Adv Specialty Chem, Bicron Opt, Capen Simulat Inc, Cleveland Crystals Inc, Crystal Associates Inc, Crystal Photon Inc, Crystal Technol Inc, Engis Corp, Engelhard-Clal LP, INRAD Inc, Johnson Matthey, Div Electr, Johnson Matthey, Div Alfa Aesar, Johnson Matthey, Div Mfg Technol, Litton Airton Synopt, Lockheed Martin Sanders, OPTOVAC, PROCHEM, Quantum Technol Inc, Sawyer Res Prod, Sensors Unltd Inc, Thermcraft Inc, II-VI Inc, Zirmat Corp ID CRYSTALLIZATION; KINETICS AB We propose a two-dimensional phase-field model of grain boundary dynamics. One-dimensional analytical solutions for a stable grain boundary in a bicrystal are obtained, and equilibrium energies are computed. By comparison with microscopic models of dislocation walls. insights into the physical accuracy of this model can be obtained. Indeed, for a particular choice of functional dependencies in the model, the grain boundary energy takes the same analytic form as the microscopic (dislocation) model of Read and Shockley. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Hokkaido Univ, Res Inst Elect Sci, Sapporo, Hokkaido 060, Japan. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RP Warren, JA (reprint author), Natl Inst Stand & Technol, Div Met, 100 Bur Dr,Stop 8554, Gaithersburg, MD 20899 USA. RI Carter, W/K-2406-2012 NR 11 TC 25 Z9 27 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 2000 VL 211 IS 1-4 BP 18 EP 20 DI 10.1016/S0022-0248(99)00856-8 PG 3 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 299LG UT WOS:000086199600006 ER PT J AU Barilo, SN Bychkov, GL Kurnevich, LA Shiryaev, SV Kurochkin, LA Lynn, JW Vasiliu-Doloc, L AF Barilo, SN Bychkov, GL Kurnevich, LA Shiryaev, SV Kurochkin, LA Lynn, JW Vasiliu-Doloc, L TI Seeded growth from flux and neutron study of La1-xBaxMnO3 (0.2 < x < 0.5) single crystals SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 11th American Conference on Crystal Growth and Epitaxy CY AUG 01-06, 1999 CL TUCSON, ARIZONA SP Assoc Crystal Growth, NASA, Div Micrograv Sci & Applicat, Adv Ceram Corp, Adv Specialty Chem, Bicron Opt, Capen Simulat Inc, Cleveland Crystals Inc, Crystal Associates Inc, Crystal Photon Inc, Crystal Technol Inc, Engis Corp, Engelhard-Clal LP, INRAD Inc, Johnson Matthey, Div Electr, Johnson Matthey, Div Alfa Aesar, Johnson Matthey, Div Mfg Technol, Litton Airton Synopt, Lockheed Martin Sanders, OPTOVAC, PROCHEM, Quantum Technol Inc, Sawyer Res Prod, Sensors Unltd Inc, Thermcraft Inc, II-VI Inc, Zirmat Corp DE lanthanum-barium manganese oxide; flux growth; magnetoresistance; spin wave spectra ID CA-MN-O; GIANT MAGNETORESISTANCE; MAGNETIC-FIELD; SPIN DYNAMICS; TRANSITION AB The flux technique for growing large crystals of La1-xBax MnO3(0.2 < x < 0.5) with a seed is discussed. Based on up to 40 wt% solubility of the solute, good rheological properties of corresponding flux melts, and desirable Ba substitution, the 25-40 mol% B2O3/45-60 mol% BaO/15-30 mol% BaF2 range of solvents has been selected to grow crystals up to 1.5 cm(3) in volume. The best crystals have been grown under constant or a very slow increase of temperature in the interval 950-1250 degrees C. Crystals with rocking curves of similar to 0.3 degrees FWHM have been obtained. Layer-by-layer X-ray fluorescent analysis has confirmed a high homogeneity of Ba distribution in volume. Neutron triple-axis measurements have been done to study the spin dynamics of the La0.68Ba0.32MnO3 crystal. Resistivity and AC-susceptibility results show that the peak occurs at a temperature T-p well above T-c (= 336 K). The data support the assumption that charge ordering exists to pin carriers. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Byelarussian Acad Sci, Inst Solid State & Semicond Phys, Minsk 220072, Byelarus. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Ctr Superconduct Res, College Pk, MD 20742 USA. RP Bychkov, GL (reprint author), Byelarussian Acad Sci, Inst Solid State & Semicond Phys, Minsk 220072, Byelarus. NR 14 TC 18 Z9 18 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD APR PY 2000 VL 211 IS 1-4 BP 480 EP 484 DI 10.1016/S0022-0248(99)00767-8 PG 5 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 299LG UT WOS:000086199600086 ER PT J AU Bowen, RL Farahani, M Dickens, SH Guttman, CM AF Bowen, RL Farahani, M Dickens, SH Guttman, CM TI MALDI-TOF MS analysis of a library of polymerizable cyclodextrin derivatives SO JOURNAL OF DENTAL RESEARCH LA English DT Article; Proceedings Paper CT 77th General Session of the International-Association-for-Dental-Research CY MAR 10-13, 1999 CL VANCOUVER, CANADA SP Int Ass Dent Res DE dental; resins; cyclodextrins; MALDI-TOF; spectrometry ID FLIGHT MASS-SPECTROMETRY AB Polymerizable cyclodextrin derivatives (PCDs) have been proposed as candidates for use in dental therapeutics (Bowen, 1996; Bowen and Reed, 1997). Here, PCD "libraries" were synthesized by quasi-random reactions of 6 moles of methacrylic anhydride plus 6 moles of cyclic glutaric anhydride per mole of beta-cyclodextrin (BCD) in solution. BCD has 21 reactive sites on each of its molecules. These proportions were based on probability calculations, which predicted that the products should have a minimum of 2 polymerizable substituents and acidic ligand groups on practically every one of the diverse product molecules. Matrix-assisted laser desorption/ionization (MALDI) time of flight (TOF) mass spectrometry (MS) gave valuable information regarding the masses of molecular ions representing the molecules that made up the PCD libraries. For the MALDI-TOF MS analyses, small samples were analyzed by the successive application of 3 solutions to the sample holder: the matrix in acetone, the products in water, and sodium trifluoroacetate in water. The resulting spectra had > 40 envelopes of mass peaks above background. The ionic-abundance peak heights had quasi-Gaussian configurations, with central peaks having masses in the neighborhood of 2000 g/mol (Daltons). Regardless of structural permutations within each peak, the range of these peaks was between about 1500 g/mol and 2900 g/mol. This range of masses was in accord with, but perhaps somewhat more narrow than, that predicted by the statistical method, which was based on equal reactivity of all hydroxyl groups. Analysis by MALDI-TOF MS gave valuable data regarding the masses, structures, and characteristics of the products formed and provided unanticipated information to facilitate improvements in future PCD syntheses. C1 Natl Inst Stand & Technol, ADA Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. US FDA, Ctr Drug Evaluat & Res, Rockville, MD 20855 USA. NIST, Div Polymers, Rockville, MD 20850 USA. RP Bowen, RL (reprint author), Natl Inst Stand & Technol, ADA Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [P50 DE09322, R37 DE05129] NR 21 TC 7 Z9 7 U1 2 U2 5 PU AMER ASSOC DENTAL RESEARCH PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD APR PY 2000 VL 79 IS 4 BP 905 EP 911 PG 7 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 312BA UT WOS:000086921800003 PM 10831091 ER PT J AU Vogel, GL Zhang, Z Chow, LC Carey, CM Schumacher, GE Banting, DW AF Vogel, GL Zhang, Z Chow, LC Carey, CM Schumacher, GE Banting, DW TI Effect of in vitro acidification on plaque fluid composition with and without a NaF or a controlled-release fluoride rinse SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE plaque fluid; rinses; fluoride; ions; acid ID CARIES-POSITIVE INDIVIDUALS; HUMAN DENTAL PLAQUE; CALCIUM-FLUORIDE; 2-SOLUTION RINSE; SALIVA; PHOSPHATE; ENAMEL; DEMINERALIZATION; SOLUBILITY; INVITRO AB Plaque fluid ion concentration changes, especially fluoride, in response to the pH decrease associated with a cariogenic episode are important components of the caries process. A "controlled-release" (CR) fluoride rinse, based on the controlled release of fluoride in the presence of calcium, has been shown to form large fluoride reservoirs in resting plaque. In this study, the in vitro acid-induced release of fluoride, and other ions, was examined in 48-hour-fasted plaque fluid from subjects (n = 11) who received no rinse, or who used a 228-ppm CR or NaF fluoride rinse 1 hr before being sampled. After collection, the plaque was centrifuged to yield plaque fluid, acidified (0.1 mu L of 0.5 mol/L HCl per milligram plaque), and then re-centrifuged before a second sample was obtained. Although previous studies indicated a higher plaque fluid fluoride after the new rinse relative to NaF, no statistically significant difference was observed here. Average fluoride release after acidification (average pH, 5.2) was statistically greater following the use of the CR rinse (153 mu mol/L) compared with the NaF rinse (17 mu mol/L). No fluoride release was seen in the no-rinse samples. The pH, Free calcium, phosphate, acetate, propionate, and buffer capacity were not affected by the different amounts of fluoride deposited in the plaque. However, following acid addition, an increase in free calcium and phosphate was observed, which was also independent of the rinse. The large release of fluoride following acidification suggests that the new rinse may provide an improved cariostatic effect. C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. Warner Lambert Co, Morris Plains, NJ 07950 USA. Univ Western Ontario, Fac Med & Dent, London, ON N6A 5C1, Canada. RP Vogel, GL (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Room A153,Bldg 224, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [DE10840, DE05354] NR 45 TC 18 Z9 18 U1 1 U2 1 PU AMER ASSOC DENTAL RESEARCH PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD APR PY 2000 VL 79 IS 4 BP 983 EP 990 PG 8 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 312BA UT WOS:000086921800014 PM 10831102 ER PT J AU Chow, LC Takagi, S Carey, CM Sieck, BA AF Chow, LC Takagi, S Carey, CM Sieck, BA TI Remineralization effects of a two-solution fluoride mouthrinse: An in situ study SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE fluoride rinse; fluoride; enamel; remineralization; calcium fluoride; sodium hexafluorosilicate; in situ model ID INTRAORAL MODELS; 2-SOLUTION RINSE; ENAMEL LESIONS; INVIVO; DEPOSITION; INVITRO; CALCIUM; CARIES; PLAQUE; SALIVA AB Results from previous studies show that a two-solution fluoride (F) rinse is significantly more effective than a NaF rinse of the same F content of 250 mu g/g (ppm) in remineralizing enamel and root lesions in an in vitro cyclic de- and remineralization model. In the present study, the two-solution rinse and two NaF rinses with F contents of 250 ppm and 1000 ppm were evaluated in an intra-oral remineralization model. Caries-like lesions were formed in the enamel of extracted human molars with the use of a pH 4 demineralizing solution. Thin sections of the enamel (approximate to 120 mu m) containing lesions were prepared, and the mineral contents of the lesions were assessed by quantitative microradiography. With the cut surfaces protected by nail varnish, 3 enamel specimens were mounted with wax in the lingual areas of a removable mandibular appliance. The study used a randomized, crossover design with seven subjects. In each of the 3 legs of the study, subjects wore the appliances continuously except when eating, drinking, and brushing their teeth. Twice daily (after breakfast and before bedtime), the subjects received a one-minute rinse with 20 mL of (1) 250-ppm-F NaF rinse, (2) 1000-ppm-F NaF rinse, or (3) 228-ppm-F two-solution F rinse. At the end of the 14-day experimental period, the sections were retrieved, and the mineral contents of the lesions were again assessed quantitatively. The results show that both the 1000-ppm-F NaF and 228-ppm-F two-solution rinses produced a greater (p < 0.05) remineralization than did the 250-ppm-F NaF rinse. The remineralization produced by the two-solution rinse was not statistically different (p > 0.05) from that produced by the NaF rinse with 4x the F content (1000 ppm F). C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenberger Res Ctr, Polymers Div, Gaithersburg, MD 20899 USA. RP Chow, LC (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenberger Res Ctr, Polymers Div, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [DE05354] NR 21 TC 25 Z9 25 U1 1 U2 4 PU AMER ASSOC DENTAL RESEARCH PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD APR PY 2000 VL 79 IS 4 BP 991 EP 995 PG 5 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 312BA UT WOS:000086921800015 PM 10831103 ER PT J AU Tokar, AS Markus, M AF Tokar, A. Sezin Markus, Momcilo TI PRECIPITATION-RUNOFF MODELING USING ARTIFICIAL NEURAL NETWORKS AND CONCEPTUAL MODELS SO JOURNAL OF HYDROLOGIC ENGINEERING LA English DT Article AB Inspired by the functioning of the brain and biological nervous systems, artificial neural networks (ANNs) have been applied to various hydrologic problems in the last 10 years. In this study, ANN models are compared with traditional conceptual models in predicting watershed runoff as a function of rainfall, snow water equivalent, and temperature. The ANN technique was applied to model watershed runoff in three basins with different climatic and physiographic characteristics-the Fraser River in Colorado, Raccoon Creek in Iowa, and Little Patuxent River in Maryland. In the Fraser River watershed, the ANN technique was applied to model monthly streamflow and was compared to a conceptual water balance (Watbal) model. The ANN technique was used to model the daily rainfall-runoff process and was compared to the Sacramento soil moisture accounting (SAC-SMA) model in the Raccoon River watershed. The daily rainfall-runoff process was also modeled using the ANN technique in the Little Patuxent River basin, and the training and testing results were compared to those of a simple conceptual rainfall-runoff (SCRR) model. In all cases, the ANN models provided higher accuracy, a more systematic approach, and shortened the time spent in training of the models. For the Fraser River, the accuracy of monthly streamflow forecasts by the ANN model was significantly higher compared to the accuracy of the Watbal model. The best-fit ANN model performed as well as the SAC-SMA model in the Raccoon River. The testing and training accuracy of the ANN model in Little Patuxent River was comparatively higher than that of the SCRR model. The initial results indicate that ANNs can be powerful tools in modeling the precipitation-runoff process for various time scales, topography, and climate patterns. C1 [Tokar, A. Sezin] Natl Weather Serv, Silver Spring, MD 20910 USA. [Markus, Momcilo] Michael Baker Jr Inc, Alexandria, VA USA. RP Tokar, AS (reprint author), Natl Weather Serv, 1325 East West Hwy, Silver Spring, MD 20910 USA. NR 24 TC 134 Z9 137 U1 0 U2 12 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 1084-0699 J9 J HYDROL ENG JI J. Hydrol. Eng. PD APR PY 2000 VL 5 IS 2 BP 156 EP 161 DI 10.1061/(ASCE)1084-0699(2000)5:2(156) PG 6 WC Engineering, Civil; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA V15AU UT WOS:000207775700005 ER PT J AU Gavrin, A Unguris, J AF Gavrin, A Unguris, J TI SEMPA imaging of domain dynamics in amorphous metals SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE SEMPA; METGLAS; domain wall motion; domain structure; magnetic instruments and techniques ID SILICON STEEL; CORE LOSS AB We show how scanning electron microscopy with polarization analysis (SEMPA) may be used to observe domain wall motion in amorphous ferromagnetic ribbons commonly used in transformer cores. SEMPA images were obtained from both the smooth, air side of the ribbon, as well as the rough, difficult to image, wheel side. Domain wall motion was studied under both quasi-static and low-frequency fields (4 Hz). The domain walls are observed to have a wide range of mobilities and are occasionally pinned by surface defects even in well-annealed samples. Irreproducible domain wall motion was also observed, but was not always obviously related to defects. This has significant implications for future attempts to use stroboscopic measurements in the study of wall mobility at higher frequencies. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Indiana Univ Purdue Univ, Dept Phys, Indianapolis, IN 46202 USA. Natl Inst Stand & Technol, Elect Phys Grp, Gaithersburg, MD 20899 USA. RP Gavrin, A (reprint author), Indiana Univ Purdue Univ, Dept Phys, 402 N Blackford St, Indianapolis, IN 46202 USA. RI Unguris, John/J-3989-2014 NR 10 TC 4 Z9 4 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD APR PY 2000 VL 213 IS 1-2 BP 95 EP 100 DI 10.1016/S0304-8853(99)00565-X PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 305FQ UT WOS:000086529100015 ER PT J AU da Costa, CT Dalluge, JJ Welch, MJ Coxon, B Margolis, SA Horton, D AF da Costa, CT Dalluge, JJ Welch, MJ Coxon, B Margolis, SA Horton, D TI Characterization of prenylated xanthones and flavanones by liquid chromatography/atmospheric pressure chemical ionization mass spectrometry SO JOURNAL OF MASS SPECTROMETRY LA English DT Article DE liquid chromatography/atmospheric pressure chemical ionization mass spectrometry; flavanones; xanthones; prenylated compounds; Maclura pomifera ID ATMOSPHERIC-PRESSURE; ROOT BARK; ISOPRENYLATED XANTHONES; MACLURA-POMIFERA; MORACEAE PLANTS; CONSTITUENTS; FRAGMENTATION; ISOFLAVONES; COMPONENTS; FLAVONOIDS AB Reversed-phase liquid chromatography with atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) in the positive-ion mode was utilized to analyze crude ether extracts from the root bark of Maclura pomifera, a tree known to have a high content of prenylated xanthones and flavanones. Identification of three xanthones and two flavanones was based on their unique mass spectra, Under optimum conditions peaks corresponding to the [MH](+) ion and characteristic fragments for each compound were observed. H-1 NMR data were used to confirm the identities of two xanthones that had the same molecular mass and similar fragmentation patterns. Fragmentation of the analytes was achieved by application of an electrostatic potential at the entrance of the single quadrupole mass spectrometer. The optimum voltage for fragmentation was found to be related to the class of compounds analyzed and, within each class, to be dependent on the structure of the prenyl moiety. Collision-induced pathways consistent with precedent literature describing the MS characterization of similar compounds and with the observed fragmentation patterns are tentatively proposed. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. American Univ, Dept Chem, Washington, DC 20016 USA. RP Dalluge, JJ (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, 100 Bur Dr,Stop 8392, Gaithersburg, MD 20899 USA. RI Barrocas Dias, Cristina/S-6824-2016 OI Barrocas Dias, Cristina/0000-0002-1707-2209 NR 28 TC 19 Z9 19 U1 1 U2 7 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 1076-5174 J9 J MASS SPECTROM JI J. Mass Spectrom. PD APR PY 2000 VL 35 IS 4 BP 540 EP 549 DI 10.1002/(SICI)1096-9888(200004)35:4<540::AID-JMS966>3.3.CO;2-P PG 10 WC Biophysics; Chemistry, Organic; Spectroscopy SC Biophysics; Chemistry; Spectroscopy GA 309AH UT WOS:000086744700005 PM 10797650 ER PT J AU Chai, H Lawn, B AF Chai, H Lawn, B TI Role of adhesive interlayer in transverse fracture of brittle layer structures SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON-NITRIDE BILAYERS; CERAMIC COATINGS; CONTACT DAMAGE; MULTILAYER MATERIALS; FLEXURAL PROPERTIES; INDENTATION; MECHANISMS AB The role of a soft adhesive interlayer in determining critical conditions for fracture in brittle layer structures from indentation with hard spheres is investigated. A model transparent trilayer system consisting of a glass plate overlayer (thickness range 80 mu m to 2 mm) joined to a glass plate underlayer (thickness 5.6 mm) by an epoxy adhesive (thickness range 5 mu m to 8 mm), loaded at its top surface with a hard tungsten carbide sphere (radius 3.96 mm), facilitates in situ observations of the crack initiation and propagation. Whereas in bulk glass fracture occurs by inner Hertzian cone cracking immediately outside the contact circle, the soft adhesive allows the overlayer glass plate to flex, initiating additional transverse fracture modes within the overlayer: downward-extending outer ring cracks at the top glass surface well outside the contact, and upward-extending radial cracks at the bottom glass surface (i.e., at the glass/adhesive interface) on median planes containing the contact axis. The top and bottom surfaces of the glass overlayers are given selective prebonding abrasion treatments to ensure uniform flaw states, so as to enable accurate comparisons between crack initiation conditions. The adhesive bonding is strong enough to preclude delamination in our layer system. Of the three transverse crack systems, the subsurface radials generates most easily in systems with large adhesive thicknesses (and smaller overlayer thicknesses). Semi-empirical relations are specified for the dependence of the critical loads for radial and ring cracking on adhesive as well as overlayer thickness, based on the assumption that crack initiation occurs when the maximum tensile stresses in the flexing glass plate exceed the bulk strength of the (abraded) glass. Coupled with the traditional "Auerbach's law" for cone crack initiation, these relations afford a basis for the construction of simple design diagrams for brittle layer systems joined by adhesives. C1 Tel Aviv Univ, Fac Engn, Dept Solid Mech Mat & Struct, IL-69978 Tel Aviv, Israel. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Tel Aviv Univ, Fac Engn, Dept Solid Mech Mat & Struct, IL-69978 Tel Aviv, Israel. NR 30 TC 44 Z9 45 U1 2 U2 13 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD APR PY 2000 VL 15 IS 4 BP 1017 EP 1024 DI 10.1557/JMR.2000.0145 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 302MH UT WOS:000086368700028 ER PT J AU Hughes, RA Brown, JM Evenson, KM AF Hughes, RA Brown, JM Evenson, KM TI Rotational spectrum of the AsH2 radical in its ground state, studied by far-infrared laser magnetic resonance SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ASYMMETRIC-TOP MOLECULES; MICROWAVE-SPECTRUM; SPECTROSCOPY; ENERGIES; PROGRAM; NH2 AB The rotational spectrum of AsH2 in its ground (X) over tilde(2)B(1) electronic state has been recorded using a far-infrared laser magnetic resonance spectrometer. The AsH2 radical was produced inside the spectrometer cavity by the reaction of arsine (AsH3) with fluorine atoms. Hyperfine splittings from both As-75 and H-1 nuclei were observed, and analysis of the spectra has yielded accurate values for rotational, hyperfine, and Zeeman parameters. (C) 2000 Academic Press. C1 Phys & Theoret Chem Lab, Oxford OX1 3QZ, England. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Hughes, RA (reprint author), Phys & Theoret Chem Lab, S Pk Rd, Oxford OX1 3QZ, England. NR 33 TC 12 Z9 12 U1 1 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD APR PY 2000 VL 200 IS 2 BP 210 EP 228 DI 10.1006/jmsp.1999.8037 PG 19 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 296KR UT WOS:000086024000007 ER PT J AU Cronin, MF McPhaden, MJ Weisberg, RH AF Cronin, MF McPhaden, MJ Weisberg, RH TI Wind-forced reversing jets in the western equatorial Pacific SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SOUTHERN OSCILLATION EVENT; OCEAN RESPONSE; ATLANTIC-OCEAN; EL-NINO; TROPICAL PACIFIC; VARIABILITY; BURSTS; THERMOCLINE; SALINITY; BALANCE AB Upper-ocean zonal currents in the western equatorial Pacific are remarkably variable, changing direction both with time and depth. As a part of the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment, an enhanced monitoring array of moorings measured the upper-ocean velocity, temperature, salinity, and, surface meteorological conditions in the western equatorial Pacific for two years (March 1992-April 1994). Data from this array are used to evaluate the zonal momentum balance. Although nonlinear terms (zonal. meridional, and vertical advection) were at times large, reversing jets were primarily due to an interplay between wind forcing and compensating pressure gradients. In the weakly stratified surface layer, the flow is to a large extent directly forced by local winds. Eastward acceleration associated with westerly wind bursts and westward accelerations associated with easterly trades lead to frequent reversals in the surface-layer flow. However, pressure gradients set up by the wind bursts partially compensate the local wind forcing in the surface layer. Below the surface layer, these pressure gradients tend to accelerate the upper-thermocline how in a direction opposing the local winds. Consequently, during westerly wind bursts. a reversing jet structure can develop, with a surface eastward current overlying a westward intermediate layer flow, overlaying the eastward Equatorial Undercurrent. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. RP Cronin, MF (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI McPhaden, Michael/D-9799-2016 NR 54 TC 21 Z9 21 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD APR PY 2000 VL 30 IS 4 BP 657 EP 676 DI 10.1175/1520-0485(2000)030<0657:WFRJIT>2.0.CO;2 PG 20 WC Oceanography SC Oceanography GA 302WL UT WOS:000086389400001 ER PT J AU Wolfenstine, J Foster, D Read, J Behl, WK Luecke, W AF Wolfenstine, J Foster, D Read, J Behl, WK Luecke, W TI Experimental confirmation of the model for microcracking during lithium charging in single-phase alloys SO JOURNAL OF POWER SOURCES LA English DT Article DE microcracking; fracture toughness; Li-alloys; anodes; indentation; brittle ID MEASURING FRACTURE-TOUGHNESS; INDENTATION TECHNIQUES AB Indentation fracture toughness measurements yielded a K-IC for Li4.4Sn equal to 0.8 +/- 0.2 MPa m(1/2). From K-IC, a critical crack length of 0.005 nm was determined for the stress generated due to the volume expansion as a result of Li charging into the Li4.4Sn alloy. The critical crack length was in excellent agreement with the predicted critical grain size for microcracking. This suggests that the model for predicting the critical grain size for microcracking during Li charging into brittle single-phase alloys is correct. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Army Res Lab, AMSRL SE DC, Adelphi, MD 20783 USA. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Wolfenstine, J (reprint author), Army Res Lab, AMSRL SE DC, Shady Grove,2800 Powder Mill Rd, Adelphi, MD 20783 USA. NR 13 TC 24 Z9 28 U1 0 U2 9 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD APR PY 2000 VL 87 IS 1-2 BP 1 EP 3 DI 10.1016/S0378-7753(99)00359-6 PG 3 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 304DY UT WOS:000086468600001 ER PT J AU Civjan, SA Engelhardt, MD Gross, JL AF Civjan, SA Engelhardt, MD Gross, JL TI Retrofit of pre-Northridge moment-resisting connections SO JOURNAL OF STRUCTURAL ENGINEERING-ASCE LA English DT Article ID PERFORMANCE AB An experimental program was undertaken to evaluate methods to retrofit existing steel moment connections for improved seismic performance. Six full-scale subassemblages were tested under cyclic loading. Typical pre-Northridge connections were retrofit by the addition of either a bottom flange dogbone or a welded bottom flange haunch. Retrofitted specimens were tested both with and without a composite floor slab. The tests showed poor performance of the bottom flange dogbone retrofit when the existing low toughness welds were left in place. Somewhat improved performance was observed when the bottom flange dogbone was combined with replacement of beam flange groove welds with higher toughness welds. The welded bottom haunch retrofit showed excellent performance on specimens with a composite slab, even though the existing low toughness beam flange groove welds were left in place. The presence of the composite slab appeared to help prevent fracture of the existing top flange weld in the haunch retrofit. This paper provides a summary of the complete experimental program. C1 Univ Massachusetts, Dept Civil & Environm Engn, Amherst, MA 01003 USA. Univ Texas, Dept Civil Engn, Phil M Ferguson Engrg Lab, Austin, TX 78758 USA. Natl Inst Stand & Technol, Struct Div, Gaithersburg, MD 20899 USA. RP Civjan, SA (reprint author), Univ Massachusetts, Dept Civil & Environm Engn, 139 Marston Hall,Box 35205, Amherst, MA 01003 USA. RI Gross, Jorge/G-9138-2012 NR 33 TC 10 Z9 10 U1 0 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9445 J9 J STRUCT ENG-ASCE JI J. Struct. Eng.-ASCE PD APR PY 2000 VL 126 IS 4 BP 445 EP 452 DI 10.1061/(ASCE)0733-9445(2000)126:4(445) PG 8 WC Construction & Building Technology; Engineering, Civil SC Construction & Building Technology; Engineering GA 297WA UT WOS:000086104600004 ER PT J AU Lynn, JW AF Lynn, JW TI Spin dynamics in the ferromagnetic phase of colossal magnetoresistive oxides SO JOURNAL OF SUPERCONDUCTIVITY LA English DT Article DE spin dynamics; ferromagnet; magnetoresistive ID DOUBLE-EXCHANGE FERROMAGNET; NEUTRON-SCATTERING; GIANT MAGNETORESISTANCE; MAGNETIC ORDER; LA1-XCAXMNO3; PYROCHLORE; TL2MN2O7; LA0.85SR0.15MNO3; LA0.7SR0.3MNO3; MANGANITE AB A review is given that focuses on the spin dynamics in the ferromagnetic regime of the magnetoresistive oxides. At small wave vectors the quadratic dispersion relation is remarkably isotropic throughout the composition range, with a gap that is too small to measure with conventional neutron scattering techniques. At larger wave vectors the spin waves are strongly damped in the ground state, in contrast to expectations based on a simple half-metallic band structure, while the temperature dependence of the damping and renormalization of the spin waves is anomalous. An unusual spin-diffusion component to the fluctuation spectrum develops as the Curie temperature is approached, which appears to be related to the formation of polarons in the system and the consequent charge localization. Near and above T-C the diffuse scattering from polarons is directly observed, as well as the correlations between the polarons. C1 Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, Ctr Superconduct Res, College Pk, MD 20742 USA. RP Lynn, JW (reprint author), Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 55 TC 21 Z9 22 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0896-1107 J9 J SUPERCOND JI J. Supercond. PD APR PY 2000 VL 13 IS 2 BP 263 EP 270 DI 10.1023/A:1007756101364 PG 8 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 294NF UT WOS:000085916800008 ER PT J AU Pauluis, O Balaji, V Held, IM AF Pauluis, O Balaji, V Held, IM TI Frictional dissipation in a precipitating atmosphere SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADIATIVE-CONVECTIVE EQUILIBRIUM; CUMULUS ENSEMBLE MODEL; CLOUD-ENSEMBLE; MOIST CONVECTION; CLIMATE AB The frictional dissipation in the shear zone surrounding falling hydrometeors is estimated to be 2-4 W m(-2) in the Tropics. A numerical model of radiative-convective equilibrium with resolved three-dimensional moist convection confirms this estimate and shows that the precipitation-related dissipation is much larger than the dissipation associated with the turbulent energy cascade from the convective scale. Equivalently, the work performed by moist convection is used primarily to lift water rather than generate kinetic energy of the convective airflow. This fact complicates attempts to use the entropy budget to derive convective velocity scales. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08540 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. RP Pauluis, O (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, POB CN710,Sayre Hall, Princeton, NJ 08540 USA. NR 14 TC 45 Z9 45 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD APR 1 PY 2000 VL 57 IS 7 BP 989 EP 994 DI 10.1175/1520-0469(2000)057<0989:FDIAPA>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 300FP UT WOS:000086242700006 ER PT J AU Valincius, G Reipa, V AF Valincius, G Reipa, V TI Differential surface stress of a tin oxide electrode SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID ADSORPTION; INTERFACES; GOLD AB Differential surface stress measurements performed using the estance technique and simultaneous measurements of the differential capacitance provide experimental evidence for deviation of n-tin oxide electrode's properties from the electrocapillary relationship that has the form of the classical Lippmann equation. The differential stress curves consist of two distinct regions. At positive potentials, where the electrical properties of n-tin oxide electrode are consistent with the Mott-Schottky model, the differential stress does not depend upon polarization and is insensitive to solution pH. Tn this region, the main contribution to the surface stress originates from the ordered dipole layer, which could include water molecules. In the negative potential range, where deviations from the Mott-Schottky model occur, the differential stress curves exhibit nonmonotonic behavior and become pH sensitive. The similar behavior of differential surface stress and semiconductor electrode charge was observed in this potential range. (C) 2000 The Electrochemical Society. S0013-4651(99)09-008-4. All rights reserved. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Vilnius State Univ, Dept Chem Phys, LT-2006 Vilnius, Lithuania. RP Valincius, G (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 35 TC 5 Z9 5 U1 1 U2 5 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD APR PY 2000 VL 147 IS 4 BP 1459 EP 1466 DI 10.1149/1.1393378 PG 8 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 302AY UT WOS:000086343800037 ER PT J AU Lu, YN Aguirre, AA Work, TM Balazs, GH Nerurkar, VR Yanagihara, R AF Lu, YN Aguirre, AA Work, TM Balazs, GH Nerurkar, VR Yanagihara, R TI Identification of a small, naked virus in tumor-like aggregates in cell lines derived from a green turtle, Chelonia mydas, with fibropapillomas SO JOURNAL OF VIROLOGICAL METHODS LA English DT Article DE green turtle fibropapilloma; Chelonia mydas; cell line; virus ID DNA AB Serial cultivation of cell lines derived from lung, testis, periorbital and tumor tissues of a green turtle (Chelonia mydas) with fibropapillomas resulted in the in vitro formation of tumor-like cell aggregates, ranging in size from 0.5 to 2.0 mm in diameter. Successful induction of tumor-like aggregates was achieved in a cell line derived from lung tissue of healthy green turtles, following inoculation with cell-free media from these tumor-bearing cell lines, suggesting the presence of a transmissible agent. Thin-section electron microscopy of the cell aggregates revealed massive collagen deposits and intranuclear naked viral particles, measuring 50 +/- 5 MI in diameter. These findings, together with the morphological similarity between these tumor-like cell aggregates and the naturally occurring tumor, suggest a possible association between this novel virus and the disease. Further characterization of this small naked virus will clarify its role in etiology of green turtle fibropapilloma. a life-threatening disease of this endangered marine species. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Univ Hawaii Manoa, Leahi Hosp, Pacific Biomed Res Ctr, Retrovirol Res Lab, Honolulu, HI 96816 USA. Tufts Univ, Sch Vet Med, Ctr Conservat Med, Wildlife Preservat Trust Int, N Grafton, MA 01536 USA. US Geol Survey, Biol Resource Div, Natl Wildlife Hlth Ctr, Honolulu Field Stn, Honolulu, HI 96850 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Lu, YN (reprint author), Univ Hawaii Manoa, Leahi Hosp, Pacific Biomed Res Ctr, Retrovirol Res Lab, 3675 Kilauea Ave, Honolulu, HI 96816 USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 FU NCRR NIH HHS [G12RR/AI-03061] NR 25 TC 11 Z9 12 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-0934 J9 J VIROL METHODS JI J. Virol. Methods PD APR PY 2000 VL 86 IS 1 BP 25 EP 33 DI 10.1016/S0166-0934(99)00175-5 PG 9 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Virology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Virology GA 296ZP UT WOS:000086056900004 PM 10713373 ER PT J AU Parsons, ECM Jefferson, TA AF Parsons, ECM Jefferson, TA TI Post-mortem investigations on stranded dolphins and porpoises from Hong Kong waters SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE bottlenose dolphin; finless porpoise; Indo-Pacific hump-backed dolphin; mortality; necropsy; Neophocaena phocaenoides; pathology; Sousa chinensis; Tursiops truncatus ID CETACEANS; POLLUTION AB Stranded cetaceans reported from the territorial waters of Hong Kong during the period May 1993 to March 1998 were examined to establish factors that may have contributed to their death. During the current study, 28 Indo-Pacific hump-backed dolphins (Sousa chinensis), 32 finless porpoises (Neophocaena phocaenoides), and four bottlenose dolphins (Tursiops truncatus) were necropsied. Bacteria (15 species) were isolated from nine animals. Of these bacteria, 47% were of possible fecal origin reflecting the high level of sewage contamination in Hong Kong's waters. One finless porpoise displayed wounds caused by a shark attack, and two female finless porpoises presented prolapsed uteri. At least 10 finless porpoises showed evidence of moderate to heavy lungworm infections (Halocercus pingi), and this appears to have been a factor contributing to death in at least six animals. Evidence suggesting blunt traumatic injury (probably caused by boat collisions) was found in six cetaceans (three finless porpoises and three humpbacked dolphins). Signs of fishery-related mortality were detected hi at least nine animals (six hump-backed dolphins, two finless porpoises, and one bottlenose dolphin). Of these two human-caused mortality types, pre-existing disease or bacterial infection were detected in 29% of cases. Results indicate that human factors may have played a significant role in the death of at least 15 animals (32% of hump-backed dolphins, 15% of finless porpoises, and 25% of bottlenose dolphins). C1 Ocean Pk Conservat Fdn, Aberdeen, Hong Kong, Peoples R China. SEAQUEST, Somerset BA5 3NX, England. RP Jefferson, TA (reprint author), NOAA, NMFS, Sw Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. EM hwdt@sol.co.uk; sclymene@aol.com RI Parsons, Edward Christien/C-2409-2011 OI Parsons, Edward Christien/0000-0002-0464-1046 NR 41 TC 50 Z9 62 U1 1 U2 16 PU WILDLIFE DISEASE ASSOC, INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 USA SN 0090-3558 J9 J WILDLIFE DIS JI J. Wildl. Dis. PD APR PY 2000 VL 36 IS 2 BP 342 EP 356 PG 15 WC Veterinary Sciences SC Veterinary Sciences GA 310XD UT WOS:000086854000019 PM 10813617 ER PT J AU Pistorius, PA Bester, MN Kirkman, SP Boveng, PL AF Pistorius, PA Bester, MN Kirkman, SP Boveng, PL TI Evaluation of age- and sex-dependent rates of tag loss in southern elephant seals SO JOURNAL OF WILDLIFE MANAGEMENT LA English DT Article DE Marion Island; mark-recapture; mark-resight; maximum likelihood; Mirounga leonina; southern elephant seals; tag loss; tag shedding ID WEDDELL SEALS; LEPTONYCHOTES-WEDDELLI; SHEDDING RATES; BLACK BEARS; FUR SEALS; REPRODUCTION; SURVIVAL AB Rates of tag loss were estimated in a long-term tagging study of southern elephant seals (Mirounga leonina) to assess the potential for bias in estimates of survival rates. Dalton Jumbo Rototags(R) were applied to each hind flipper of 5,743 recently weaned elephant seal pups on Marion Island from 1983 to 1993. We adapted and developed a Method based on the resighting times of seals retaining 1 or 2 tags to estimate tag loss and test for effects of age and sex of the seals. Tag loss by young seals was low but there was a strong increase in tag loss with seal age, especially for males. Annual single tag loss at age 14 was 10% for males and 5.6% for females. Although these are relatively modest rates of tag loss, substantial fractions of seals (35% of males and 17% of females) would lose both tags by age 15, requiring corrections to avoid bias in demographic studies based on these tagging data. The method we used to estimate tag loss has significant advantages over a ratio estimator that has been used for most previous studies of tag loss in pinnipeds. C1 Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, NOAA, Seattle, WA 98115 USA. Univ Pretoria, Dept Zool & Entomol, Mammal Res Inst, ZA-0002 Pretoria, South Africa. RP Boveng, PL (reprint author), Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, NOAA, 7600 Sand Point Way NE,Bin C15700, Seattle, WA 98115 USA. NR 25 TC 34 Z9 35 U1 0 U2 6 PU WILDLIFE SOC PI BETHESDA PA 5410 GROSVENOR LANE, BETHESDA, MD 20814-2197 USA SN 0022-541X J9 J WILDLIFE MANAGE JI J. Wildl. Manage. PD APR PY 2000 VL 64 IS 2 BP 373 EP 380 DI 10.2307/3803235 PG 8 WC Ecology; Zoology SC Environmental Sciences & Ecology; Zoology GA 305MD UT WOS:000086543100006 ER PT J AU Friday, N Smith, TD Stevick, PT Allen, J AF Friday, N Smith, TD Stevick, PT Allen, J TI Measurement of photographic quality and individual distinctiveness for the photographic identification of humpback whales, Megaptera novaeangliae SO MARINE MAMMAL SCIENCE LA English DT Article DE humpback whale; Megaptera novaeangliae; photographic identification; individual identification; mark-recapture; photographic quality; individual animal distinctiveness; kappa statistics; cumulative logit model; categorical data analyses ID POPULATION CHARACTERISTICS; OBSERVER-AGREEMENT AB Accurate identification of humpback whales from photographic identification data depends on the quality of the photographs and the distinctiveness of the flukes. Criteria for evaluating photographic quality and individual distinctiveness were developed involving judgments about overall quality or distinctiveness and about specific aspects of each. These criteria were tested for the level of agreement among judges. The distinctiveness scheme was tested for the independence of distinctiveness judgments and photographic quality. Our results show that judges could agree when evaluating specific and overall aspects of photographic quality and individual distinctiveness. The level of agreement varied for different pairs of judges, and less adept judges were identified. Ability to agree on evaluations of photographic quality was independent: of the experience of the judges. Overall photographic quality and overall distinctiveness were successfully predicted from more specific variables, but the agreement between judges for these was not significantly greater than the agreement for the overall measures judged directly. There was no correlation between individual distinctiveness and photographic quality for four of the five judges, but the power of this test may be low. Analysts of photographic identification data frequently require evaluations of photographic quality and individual distinctiveness. To obtain reliable results from such analyses, evaluation schemes and judges should be tested to ensure reliable and consistent evaluations. C1 NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Coll Atlantic, Bar Harbor, ME 04609 USA. RP Friday, N (reprint author), NE Fisheries Sci Ctr, 166 Water St, Woods Hole, MA 02543 USA. EM nancy.iriday@noaa.gov NR 37 TC 62 Z9 76 U1 3 U2 22 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0824-0469 EI 1748-7692 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 2000 VL 16 IS 2 BP 355 EP 374 DI 10.1111/j.1748-7692.2000.tb00930.x PG 20 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 297WT UT WOS:000086106200007 ER PT J AU Parrish, FA Craig, MP Ragen, TJ Marshall, GJ Buhleier, BM AF Parrish, FA Craig, MP Ragen, TJ Marshall, GJ Buhleier, BM TI Identifying diurnal foraging habitat of endangered Hawaiian monk seals using a seal-mounted video camera SO MARINE MAMMAL SCIENCE LA English DT Article DE Hawaiian monk seal; Monachus schauinslandi; foraging habitat; CRITTERCAM; endangered species ID MONACHUS-SCHAUINSLANDI; FEEDING-HABITS; PHOCA-GROENLANDICA; MOVEMENTS; ISLANDS; REEF; DIET AB The Hawaiian monk seal (Monachus schauinslandi) is thought to be a foraging generalist, preying on numerous species in diverse habitats of the subtropical Northwestern Hawaiian Islands. Ac che atoll of French Frigate Shoals, recent evidence of emaciation and low survival in monk seals prompted a search for their specific prey communities and foraging habitat. A video camera (National Geographic Television's CRITTERCAM) fitted to 24 adult male seals documented benthic and demersal foraging on the deep slopes (50-80 m) of the atoll and neighboring banks. The number of bottom searches for prey was compared by year, time of day, type of bottom, individual seal, and length of bottom time. Analysis of variance identified a significant interaction of seal and bottom type, explaining 65% of the coral variance. Seals fed on communities of cryptic fauna (fish and large invertebrates) in transitional "ecotone" regions of low relief where consolidated substrate, rubble, and talus bordered areas of sand. Independent areal surveys of bottom types throughout the atoll and neighboring banks suggest that the type of bottom selected as foraging habitat represents a relatively small percentage of the total benthic area available. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. NOAA, NMFS, Juneau, AK 99801 USA. Natl Geog Televis, Washington, DC 20036 USA. RP Parrish, FA (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, 2570 Dole St, Honolulu, HI 96822 USA. EM frank.parrish@noaa.gov NR 46 TC 47 Z9 54 U1 3 U2 16 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0824-0469 EI 1748-7692 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 2000 VL 16 IS 2 BP 392 EP 412 DI 10.1111/j.1748-7692.2000.tb00932.x PG 21 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 297WT UT WOS:000086106200009 ER PT J AU Bentz, DP Quenard, DA Kunzel, HM Baruchel, J Peyrin, F Martys, NS Garboczi, EJ AF Bentz, DP Quenard, DA Kunzel, HM Baruchel, J Peyrin, F Martys, NS Garboczi, EJ TI Microstructure and transport properties of porous building materials. II: Three-dimensional X-ray tomographic studies SO MATERIALS AND STRUCTURES LA English DT Article ID MICROTOMOGRAPHY; DIFFUSIVITY; MEDIA; PERMEABILITY AB Three-dimensional X-ray microtomography is used to obtain three-dimensional images of the microstructure of two types of brick. The images are processed to remove the noise (random and circular pattern) and then thresholded to match the porosity determined experimentally. The 3-D binary images are then analyzed to estimate their vapor diffusivity and air permeability to compare to experimental data published in part one of this report. Care must be taken in obtaining the tomographic images at a resolution that both enables isolation and quantification of the pores of interest and provides a representative elementary volume for the transport property calculations. In general, the agreement between computed and measured properties is reasonable, suggesting that X-ray microtomography can provide valuable information on the characteristics and properties of the pore networks developed in these porous building materials. A preliminary evaluation indicates that the Katz-Thompson relationship between permeability, diffusivity, and pore size is valid for these materials. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Ctr Sci & Tech Batiment, F-38400 St Martin Dheres, France. Fraunhofer Inst Bauphys, D-83601 Holzkirchen, Germany. ESRF, Grenoble, France. INSA, CREATIS, Lyon, France. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RI Peyrin, Francoise/G-2823-2013 OI Peyrin, Francoise/0000-0002-1988-3435 NR 19 TC 60 Z9 61 U1 0 U2 11 PU R I L E M Publications PI cachan cedex PA 61 ave president wilson, 94235 cachan cedex, FRANCE SN 1359-5997 J9 MATER STRUCT JI Mater. Struct. PD APR PY 2000 VL 33 IS 227 BP 147 EP 153 DI 10.1007/BF02479408 PG 7 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 312YU UT WOS:000086972200002 ER PT J AU Semerjian, HG Watters, RL AF Semerjian, HG Watters, RL TI Impact of measurement and standards infrastucture on the national economy and international trade SO MEASUREMENT LA English DT Article DE metrology; impact; trade AB The U.S, federal government has a strong role in metrology R&D in the U.S, because of its importance to the nation's economy and the Constitutional authority given to the National Institute of Standards and Technology (NIST). However, pressures to maintain a balanced budget require careful planning and priority setting to win support for metrology R&D programs. The payoffs of good planning and resource deployment come in the form of anecdotal examples of significant industrial outcomes and comprehensive evidence of impacts through formalized studies. Furthermore, when tariff-based barriers to intel national trade are lowered, consistent and accurate measurements that are globally accepted facilitate the elimination of any remaining technical barriers to trade. We will explore these issues, giving specific examples of impacts from recent work at the National institute of Standards and Technology. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Semerjian, HG (reprint author), NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 18 TC 3 Z9 4 U1 2 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-2241 J9 MEASUREMENT JI Measurement PD APR PY 2000 VL 27 IS 3 BP 179 EP 196 DI 10.1016/S0263-2241(99)00065-2 PG 18 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 317BE UT WOS:000087203300003 ER PT J AU Gnaupel-Herold, T Prask, HJ Clark, AV Hehman, CS Nguyen, TN AF Gnaupel-Herold, T Prask, HJ Clark, AV Hehman, CS Nguyen, TN TI A comparison of neutron and ultrasonic determinations of residual stress SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE strain; residual stress; electromagnetic-acoustic transducer; neutron diffraction; standards and calibration; field-capable stress measurement ID DIFFRACTION AB Stress is a principal cause of material failure. This has been a well-recognized problem for decades yet neutron diffraction remains the only unambiguous way to measure sub-surface residual stresses without either destroying the component or having access to a reference state. An array of stress-measurement standards that are characterized by neutron diffraction is being developed to evaluate quantitatively the potential of other methods. In the present work an aluminium ring-plug reference specimen was fabricated to provide a means for testing new techniques to be used for the determination of residual stress. The residual-stress distribution in the ring plug was determined by neutron diffraction and strain gauges. The distribution was in excellent agreement with that expected From elasticity theory. The ring plug was also studied using an electromagnetic-acoustic transducer (EMAT) as an 'ultrasonic strain gauge'. Results over the region of the specimen examined were in excellent agreement with the other techniques and represent an excellent first step towards validating a field-portable residual-strain gauge. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. MDK Inc, Chapel Hill, NC 27515 USA. GE Co, Salem, VA 24153 USA. RP Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI 苏, 日亮/D-4386-2009; OI Gnaupel-Herold, Thomas/0000-0002-8287-5091 NR 18 TC 10 Z9 11 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD APR PY 2000 VL 11 IS 4 BP 436 EP 444 DI 10.1088/0957-0233/11/4/315 PG 9 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 309XD UT WOS:000086793800015 ER PT J AU Collins, BL AF Collins, BL TI A standards infrastructure for the future SO MECHANICAL ENGINEERING LA English DT Article C1 NIST, Off Stand Serv, Gaithersburg, MD 20899 USA. RP Collins, BL (reprint author), NIST, Off Stand Serv, Gaithersburg, MD 20899 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0025-6501 J9 MECH ENG JI Mech. Eng. PD APR PY 2000 VL 122 IS 4 BP 86 EP 92 PG 7 WC Engineering, Mechanical SC Engineering GA 412XL UT WOS:000167579600047 ER PT J AU Williamson, JF Coursey, BM DeWerd, LA Hanson, WF Nath, R Rivard, MJ Ibbott, G AF Williamson, JF Coursey, BM DeWerd, LA Hanson, WF Nath, R Rivard, MJ Ibbott, G TI Recommendations of the American Association of Physicists in Medicine on Pd-103 interstitial source calibration and dosimetry: Implications for dose specification and prescription SO MEDICAL PHYSICS LA English DT Article DE Pd-103 brachytherapy; air-kerma strength; dose prescriptions ID BRACHYTHERAPY; SEEDS; CARCINOMA AB The National Institute of Standards and Technology (NIST) introduced a national standard for air kerma strength of the ThreaSeed(R) Model 200 Pd-103 source (the only Pd-103 Seed available until 1999) in early 1999. Correct implementation of the NIST-99 standard requires the use of dose rate constants normalized to this same standard. Prior to the availability of this standard, the vendor's calibration procedure consisted of intercomparing Model 200 seeds with a Cd-109 source with a NIST-traceable activity calibration. The AAPM undertook a comprehensive review of Pd-103 source dosimetry including (i) comparison of the vendor and NIST-99 calibration standards; (ii) comparison of original Task Group 43 dosimetry parameters with more recent studies; (iii) evaluation of the vendor's calibration history; and (iv) evaluation of administered-to-prescribed dose ratios from the introduction of Pd-103 sources in 1987 to the present. This review indicates that for a prescribed dose of 115 Gy, the administered doses were (a) 124 Gy for the period 1988-1997 and (b) 135 Gy for the period 1997-1999. The AAPM recommends that the following three steps should be undertaken concurrently to implement correctly the 1999 dosimetry data and NIST-99 standard for Pd-103 source: (1) the vendor should provide calibrations in terms of air kerma strength traceable to NIST-99 standard, (2) the medical physicist should update the treatment planning system with properly normalized (to NIST-99) dosimetry parameters for the selected Pd-103 source model, and (3) the radiation oncologist in collaboration with the medical physicist should decide which clinical experience they wish to duplicate; the one prior to 1997 or the one from 1997 to 1999. If the intent is to duplicate the experience prior to 1997, which is backed by the long-term follow-up and published outcome studies, then the prior prescriptions of 115 Gy should be replaced by 124 Gy to duplicate that experience. (C) 2000 American Association of Physicists in Medicine. C1 Washington Univ, Med Ctr, Radiat Oncol Ctr, St Louis, MO 63110 USA. Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. Univ Wisconsin, Accredited Dosimetry & Calibrat Lab, Madison, WI 53706 USA. Univ Texas, MD Anderson Canc Ctr, Radiol Phys Ctr, Houston, TX 77030 USA. Yale Univ, Dept Therapeut Radiol, New Haven, CT 06510 USA. New England Med Ctr, Dept Radiat Oncol, Boston, MA 02111 USA. Univ Kentucky, Dept Radiat Med, Lexington, KY 40536 USA. RP Williamson, JF (reprint author), Washington Univ, Med Ctr, Radiat Oncol Ctr, 510 S Kingshighway Blvd, St Louis, MO 63110 USA. NR 23 TC 50 Z9 50 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD APR PY 2000 VL 27 IS 4 BP 634 EP 642 DI 10.1118/1.598923 PG 9 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 306UN UT WOS:000086615200002 PM 10798683 ER PT J AU Bambynek, M Fluhs, D Quast, U Wegener, D Soares, CG AF Bambynek, M Fluhs, D Quast, U Wegener, D Soares, CG TI A high-precision, high-resolution and fast dosimetry system for beta sources applied in cardiovascular brachytherapy SO MEDICAL PHYSICS LA English DT Article DE plastic scintillator dosimeter; absorbed dose calibration; beta-dosimetry; intravascular brachytherapy; vascular restenosis ID PLASTIC SCINTILLATION DETECTORS; LUMINAL CORONARY ANGIOPLASTY; MUSCLE CELL-PROLIFERATION; ENERGY BEAM DOSIMETRY; ENDOVASCULAR BRACHYTHERAPY; STENT IMPLANTATION; RESTENOSIS; PREVENTION; RADIATION; IRRADIATION AB A fast dosimetry system based on plastic scintillator detectors has been developed which allows three-dimensional measurement of the radiation field in water of beta-sources appropriate for application in cardiovascular brachytherapy. This system fulfills the AAPM Task Group 60 recommendations for dosimetry of cardiovascular brachytherapy sources. To demonstrate the use of the system, measurements have been performed with an Y-90-wire source. The dose distribution was determined with a spatial resolution of better than 0.2 mm, with only a few minutes needed per scan. The scintillator dosemeter was absolutely calibrated in terms of absorbed dose to water with a precision of +/-7.5%. The relative precision achievable is +/-2.5%. The response of the system is linear within +/-2% for dose rates from 0.5 mGy s(-1) to 500 mGy s(-1). (C) 2000 American Association of Physicists in Medicine. C1 Essen Univ Hosp, Div Clin Radiat Phys, D-45122 Essen, Germany. Univ Dortmund, Inst Phys, D-44221 Dortmund, Germany. Natl Inst Stand & Technol, Radiat Interact & Dosimetry Grp, Gaithersburg, MD 20899 USA. RP Bambynek, M (reprint author), Essen Univ Hosp, Div Clin Radiat Phys, Huferlandstr 55, D-45122 Essen, Germany. RI Grams, Michael/G-5197-2011 NR 28 TC 30 Z9 30 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD APR PY 2000 VL 27 IS 4 BP 662 EP 667 DI 10.1118/1.598927 PG 6 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 306UN UT WOS:000086615200006 PM 10798687 ER PT J AU Groben, R Doucette, GJ Kopp, M Kodama, M Amann, R Medlin, LK AF Groben, R Doucette, GJ Kopp, M Kodama, M Amann, R Medlin, LK TI 16S rRNA targeted probes for the identification of bacterial strains isolated from cultures of the toxic dinoflagellate Alexandrium tamarense SO MICROBIAL ECOLOGY LA English DT Article ID RIBOSOMAL DATABASE PROJECT; RNA; TETRODOTOXIN; REV AB Bacteria have been implicated in the production of paralytic shellfish poison (PSP) toxins, which are normally associated with bloom-forming algal species, specifically toxic dinoflagellate algae. To clarify the role that these bacteria may play in the production of PSP toxins, it is desirable to identify and localize the bacteria associated with the dinoflagellates. 16S rRNA-targeted probes offer the possibility for both, and thus, probes have been made to putatively toxigenic bacteria isolated from the PSP-related dinoflagellate Alexandrium tamarense and tested for their specificity in dot blot and in situ hybridization experiments. C1 Alfred Wegener Inst Polar & Meeresforsch, D-27570 Bremerhaven, Germany. Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Charleston, SC 29412 USA. Kitasato Univ, Sch Fisheries Sci, Lab Marine Biol Chem, Sanriku, Iwate 02201, Japan. Max Planck Inst Marine Mikrobiol, D-28359 Bremen, Germany. RP Medlin, LK (reprint author), Alfred Wegener Inst Polar & Meeresforsch, Handelshafen 12, D-27570 Bremerhaven, Germany. RI medlin, linda/G-4820-2010; Groben, Rene/A-8457-2012; Doucette, Gregory/M-3283-2013; Amann, Rudolf/C-6534-2014 OI Groben, Rene/0000-0003-3034-2629; Amann, Rudolf/0000-0002-0846-7372 NR 39 TC 17 Z9 18 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD APR PY 2000 VL 39 IS 3 BP 186 EP 196 PG 11 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 331HC UT WOS:000088011800002 ER PT J AU Bender, MA Ginis, I AF Bender, MA Ginis, I TI Real-case simulations of hurricane-ocean interaction using a high-resolution coupled model: Effects on hurricane intensity SO MONTHLY WEATHER REVIEW LA English DT Article ID AIR-SEA INTERACTION; TROPICAL CYCLONE; NUMERICAL SIMULATIONS; PREDICTION SYSTEM; GULF-STREAM; IMPROVEMENTS; SENSITIVITY; ATMOSPHERE; GILBERT; MOTION AB In order to investigate the effect of tropical cyclone-ocean interaction on the intensity of observed hurricanes, the GFDL movable triply nested mesh hurricane model was coupled with a high-resolution version of the Princeton Ocean Model. The ocean model had 1/6 degrees uniform resolution, which matched the horizontal resolution of the hurricane model in its innermost grid. Experiments were run with and without inclusion of the coupling for two cases of Hurricane Opal (1995) and one case of Hurricane Gilbert (1988) in the Gulf of Mexico and two cases each of Hurricanes Felix (1995) and Fran (1996) in the western Atlantic. The results confirmed the conclusions suggested by the earlier idealized studies that the cooling of the sea surface induced by the tropical cyclone will have a significant impact on the intensity of observed storms, particularly for slow moving storms where the SST decrease is greater. In each of the seven forecasts, the ocean coupling led to substantial improvements in the prediction of storm intensity measured by the storm's minimum sea level pressure. Without the effect of coupling the GFDL model incorrectly forecasted 25-hPa deepening of Gilbert as it moved across the Gulf of Mexico. With the coupling included, the model storm deepened only 10 hPa, which was much closer to the observed amount of 4 hPa. Similarly, during the period that Opal moved very slowly in the southern Gulf of Mexico, the coupled model produced a large SST decrease northwest of the Yucatan and slow deepening consistent with the observations. The uncoupled model using the initial NCEP SSTs predicted rapid deepening of 58 hPa during the same period. Improved intensity prediction was achieved both for Hurricanes Felix and Fran in the western Atlantic. For the case of Hurricane Fran, the coarse resolution of the NCEP SST analysis could not resolve Hurricane Edouard's wake, which was produced when Edouard moved in nearly an identical path to Fran four days earlier. As a result, the operational GFDL forecast using the operational SSTs and without coupling incorrectly forecasted 40-hPa deepening while Fran remained at nearly constant intensity as it crossed the wake. When the coupled model was run with Edouard's cold wake generated by imposing hurricane wind forcing during the ocean initialization, the intensity prediction was significantly improved. The model also correctly predicted the rapid deepening that occurred as Fran began to move away from the cold wake. These results suggest the importance of an accurate initial SST analysis as well as the inclusion of the ocean coupling, for accurate hurricane intensity prediction with a dynamical model. Recently, the GFDL hurricane-ocean coupled model used in these case studies was run on 163 forecasts during the 1995-98 seasons. Improved intensity forecasts were again achieved with the mean absolute error in the forecast of central pressure reduced by about 268 compared to the operational GFDL model. During the 1998 season, when the system was run in near-real time, the coupled model improved the intensity forecasts for all storms with central pressure higher than 940 hPa although the most significant improvement (similar to 60%) occurred in the intensity range of 960-970 hPa. These much larger sample sets confirmed the conclusion from the case studies, that the hurricane-ocean interaction is an important physical mechanism in the intensity of observed tropical cyclones. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. RP Bender, MA (reprint author), Princeton Univ, NOAA, GFDL, Forrestal Campus,US Route 1, Princeton, NJ 08542 USA. NR 52 TC 198 Z9 214 U1 4 U2 18 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 2000 VL 128 IS 4 BP 917 EP 946 DI 10.1175/1520-0493(2000)128<0917:RCSOHO>2.0.CO;2 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302ZG UT WOS:000086395900001 ER PT J AU MacDonald, AE Lee, JL Sun, S AF MacDonald, AE Lee, JL Sun, S TI QNH: Design and test of a quasi-nonhydrostatic model for mesoscale weather prediction SO MONTHLY WEATHER REVIEW LA English DT Article ID BAROCLINIC WAVES; PARAMETERIZATION; EQUATIONS; SCALES; FLOW AB A new mesoscale weather prediction model, called QNH, is described. It is characterized by a parameter that multiplies the hydrostatic terms in the vertical equation of motion. Models of this type are referred to generically as "quasi-nonhydrostatic." The quasi-nonhydrostatic parameter gives the model a character that is essentially nonhydrostatic, but with properties that are theoretically thought to result in smoother, more: accurate, and stable predictions. The model is unique in a number of other aspects, such as its treatment of lateral boundary conditions, the use of explicit calculation in the vertical direction, and the use of the hounded derivative theory for initialization This paper reports on the design and test of the QNH model, which represents the first time the applicability of this type of model has been demonstrated for full-physics, mesoscale weather prediction. The dynamic formulation, discretization, numerical formulation, and physics packages of the model are described. The results of a comprehensive validation of the model are presented. The validation includes barotropic baroclinic (Eady wave), mountain wave, tropical storm, and sea breeze tests. A simulation of a winter storm (with updated lateral boundary conditions) is presented, which shows that the model has significant skill in forecasting terrain-forced heavy precipitation. It is concluded that the QNH model may be valuable for mesoscale weather prediction. C1 NOAA, ERL, R E FS, Forecast Syst Lab, Boulder, CO 80523 USA. Colorado State Univ, CIRA, Ft Collins, CO 80523 USA. NASA, Goddard Inst, New York, NY USA. RP MacDonald, AE (reprint author), NOAA, ERL, R E FS, Forecast Syst Lab, 325 Broadway, Boulder, CO 80523 USA. RI Lee, JIN-LUEN/G-5364-2015; Sun, Shan/H-2318-2015 NR 34 TC 16 Z9 16 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 2000 VL 128 IS 4 BP 1016 EP 1036 DI 10.1175/1520-0493(2000)128<1016:QDATOA>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302ZG UT WOS:000086395900005 ER PT J AU Lee, JL MacDonald, AE AF Lee, JL MacDonald, AE TI QNH: Mesoscale bounded derivative initialization and winter storm test over complex terrain SO MONTHLY WEATHER REVIEW LA English DT Article ID NORMAL-MODE INITIALIZATION; DIABATIC INITIALIZATION; PRIMITIVE EQUATIONS; HIRLAM MODEL; IMPROVEMENT; ATMOSPHERE; DIVERGENCE; SYSTEMS AB Mesoscale bounded derivative initialization (BDI) is utilized to derive dynamical constraints, from which elliptic equations are formulated to derive smooth initial fields over complex terrain for mesoscale models. The initialization is implemented specifically for the quasi-nonhydrostatic (QNH) model. This study presents the first real data application of the mesoscale BDI and the QNH model to simulate a mesoscale storm that produced heavy precipitation along the Colorado Front Range. In this study, the focus is on (i) smooth numerical solution over complex terrain, (ii) baroclinic instability associated with condensational heating and high mountains, and (iii) the simulation of orographic precipitation. Numerical results show that initial fields derived from BDI were smooth and evolved smoothly in the QNH model for 48 h. It is noteworthy that the smooth solution existed up to the lateral boundaries. During the 48-h simulation, the midtropospheric storm moved freely in and out of the limited-area domain as if there were no lateral boundaries. The mesoscale storm for northeast Colorado was initiated by the persistent upslope easterlies and strong upward motions that triggered heavy precipitation. The simulated precipitation amounts and pattern were in good agreement with those observed. In general, both the large-scale dynamic system and the mesoscale precipitation event evolved smoothly and accurately, which indicates the value of BDI and QNH for mesoscale weather prediction. C1 NOAA, ERL, Forecast Syst Lab, R,E,FS, Ft Collins, CO 80523 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. RP Lee, JL (reprint author), NOAA, ERL, Forecast Syst Lab, R,E,FS, 325 Broadway, Ft Collins, CO 80523 USA. RI Lee, JIN-LUEN/G-5364-2015 NR 31 TC 6 Z9 7 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 2000 VL 128 IS 4 BP 1037 EP 1051 DI 10.1175/1520-0493(2000)128<1037:QMBDIA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302ZG UT WOS:000086395900006 ER PT J AU Brooks, HE Stensrud, DJ AF Brooks, HE Stensrud, DJ TI Climatology of heavy rain events in the United States from hourly precipitation observations SO MONTHLY WEATHER REVIEW LA English DT Article ID BIG THOMPSON STORM; FLOOD; WSR-88D AB Flash flooding is frequently associated with heavy precipitation (defined here as greater than or equal to 1 in. h(-l)) occurring over a short period of time. To begin a study of flash hood-producing rain events, the Hourly Precipitation Dataset (HPD) is used to develop a climatology of heavy rains on timescales of 3 h or less across the contiguous United States. Analyses of this dataset show a distinct seasonal cycle in the distribution of heavy rain events that begins along the Gulf Coast and expands into the midwestern states during the summer. This general evolution is very similar to that observed for hash floods, suggesting that the HPD can help in defining the climatological threat for flash floods. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Brooks, HE (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 17 TC 40 Z9 43 U1 0 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD APR PY 2000 VL 128 IS 4 BP 1194 EP 1201 DI 10.1175/1520-0493(2000)128<1194:COHREI>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302ZG UT WOS:000086395900017 ER PT J AU Ramseyer, LJ AF Ramseyer, LJ TI Utilization of semipurified diets by tautog SO NORTH AMERICAN JOURNAL OF AQUACULTURE LA English DT Article ID RAINBOW-TROUT; CHANNEL CATFISH; SALMONIDS; CUNNER; REQUIREMENTS; PROTEIN; CULTURE; TRYPSIN; GROWTH; ENZYME AB Experiments were conducted to determine whether semipurified diets would support growth in the tautog Tautoga onitis, a stomachless fish. Semipurified diets contained 50% protein and either 7% or 12% lipid on a dry-matter basis. A commercial salmonid feed containing 54% protein and 15% lipid on a dry-matter basis was used as a reference feed. Semipurified diets were either "as is," with intrinsic pH of 5.5-5.8 or with pH adjusted during preparation to 7.2-7.6. Experiments were conducted with 6-13-g tautogs at 20 degrees C for 28-31 d, and diets were fed at daily rates providing 14 g protein/kg body weight. Alkalinizing the 7%-lipid semipurified diet pH from 5.5 to 7.2 resulted in a significant (P < 0.05) increase in tautog growth rate. However, growth of tautogs fed the reference feed was significantly (P < 0.05) greater than growth achieved by fish fed either of the 7%-lipid semipurified diets. Semipurified diets containing 50% protein and 12% lipid supported growth in tautog at a rate comparable to the reference feed. C1 Natl Marine Fisheries Serv, Natl Acad Sci, Milford Lab, Milford, CT 06460 USA. RP Ramseyer, LJ (reprint author), Natl Marine Fisheries Serv, Natl Acad Sci, Milford Lab, 212 Rogers Ave, Milford, CT 06460 USA. NR 20 TC 0 Z9 0 U1 0 U2 2 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 1522-2055 J9 N AM J AQUACULT JI N. Am. J. Aqualcult. PD APR PY 2000 VL 62 IS 2 BP 125 EP 129 DI 10.1577/1548-8454(2000)062<0125:UOSDBT>2.0.CO;2 PG 5 WC Fisheries SC Fisheries GA 351ZN UT WOS:000089190200005 ER PT J AU Broeuf, N Branning, D Chaperot, I Dauler, E Guerin, S Jaeger, G Muller, A Migdall, A AF Broeuf, N Branning, D Chaperot, I Dauler, E Guerin, S Jaeger, G Muller, A Migdall, A TI Calculating characteristics of noncollinear phase matching in uniaxial and biaxial crystals SO OPTICAL ENGINEERING LA English DT Article DE nonlinear optics; crystals; photons; radiometry AB A method of calculating the characteristics of noncollinear phase matching in both uniaxial and biaxial crystals is presented. Although significant work has been done to characterize collinear phase matching and to present many of its applications, noncollinear phase matching also has unique characteristics, leading to several useful applications. The method presented enables calculations of both the collinear and noncollinear cases, and enables a far larger set of nonlinear crystals and configurations to be studied. (C) 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)02304-7]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Migdall, A (reprint author), Natl Inst Stand & Technol, Opt Technol Div, 100 Bur Dr,Stop 8441, Gaithersburg, MD 20899 USA. OI Jaeger, Gregg/0000-0002-5725-6491 NR 12 TC 42 Z9 44 U1 3 U2 4 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD APR PY 2000 VL 39 IS 4 BP 1016 EP 1024 DI 10.1117/1.602464 PG 9 WC Optics SC Optics GA 302QD UT WOS:000086375900022 ER PT J AU Rahmani, A Bryant, GW AF Rahmani, A Bryant, GW TI Contribution of evanescent waves to the far field: the atomic point of view SO OPTICS LETTERS LA English DT Article ID QUANTUM ELECTRODYNAMICS; FLUCTUATIONS; DIELECTRICS; RESOLUTION AB Evanescent modes of the electromagnetic field are seldom invoked in conventional far-field optics, as their contribution far from the source (a few wavelengths) is negligible. Contradicting this fact, in recent theoretical works, based on a particular decomposition of the free-space Green tensor, it has been asserted that evanescent waves do indeed contribute to the far field, where they appear as an additional similar to 1/r component of the field. We provide an explicit demonstration that evanescent modes do not contribute to the power radiated to the far field by any dipolar source. First we derive an expression for the free-space field susceptibility in which contributions from evanescent and homogeneous modes are separated, and then we use linear response theory to compute the decay rate for an atomic dipole in vacuum. (C) 2000 Optical Society of America OCIS codes: 260.2510, 350.5610. C1 Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Rahmani, A (reprint author), Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RI Rahmani, Adel/G-6406-2011 NR 26 TC 9 Z9 9 U1 0 U2 0 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 APR 1 PY 2000 VL 25 IS 7 BP 433 EP 435 DI 10.1364/OL.25.000433 PG 3 WC Optics SC Optics GA 298TW UT WOS:000086156100001 PM 18064070 ER PT J AU Amelink, A Jones, KM Lett, PD van der Straten, P Heideman, HGM AF Amelink, A Jones, KM Lett, PD van der Straten, P Heideman, HGM TI Spectroscopy of autoionizing doubly excited states in ultracold Na-2 molecules produced by photoassociation SO PHYSICAL REVIEW A LA English DT Article ID ASSOCIATIVE IONIZATION; 2-COLOR PHOTOASSOCIATION; ATOMS; SODIUM; COEFFICIENTS; COLLISIONS; POTENTIALS; DYNAMICS AB We have performed photoassociation spectroscopy to study the doubly excited states of Na-2 involved in the associative ionization of colliding Na(3 P) atoms. Rovibrational levels of two doubly excited potentials connected to the P-3/2+P-3/2 asymptote, one of O-u(-) and one of 1(u) symmetry, have been identified. These two doubly excited potentials dominate the route to ionization used in photoassociation experiments of cold Na. Binding energies and rotational constants for all the vibrational levels with binding energies <50 GHz have been measured. The asymptotic potentials and short-range ionization probabilities are extracted from the data. C1 Univ Utrecht, Debye Inst, Dept Atom & Interface Phys, NL-3508 TA Utrecht, Netherlands. Natl Inst Stand & Technol, Div Atom Phys, Gaithersburg, MD 20899 USA. RP Amelink, A (reprint author), Univ Utrecht, Debye Inst, Dept Atom & Interface Phys, POB 80 000, NL-3508 TA Utrecht, Netherlands. RI Institute (DINS), Debye/G-7730-2014; van der Straten, Peter/H-9356-2016 NR 26 TC 17 Z9 17 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2000 VL 61 IS 4 AR 042707 DI 10.1103/PhysRevA.61.042707 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 301ME UT WOS:000086313300048 ER PT J AU Kotochigova, S Tiesinga, E Tupitsyn, I AF Kotochigova, S Tiesinga, E Tupitsyn, I TI Nonrelativistic ab initio calculation of the interaction potentials between metastable Ne atoms SO PHYSICAL REVIEW A LA English DT Article ID LOW-LYING STATES; VALENCE BOND WAVEFUNCTIONS; EXCITED-STATES; NA ATOMS; COLLISIONS; CURVES; O2 AB We compute nonrelativistic ab initio electronic potential surfaces for two metastable 2p(5) 3s neon atoms using a multiconfiguration all-electron valence-bond method. Spectroscopic constants and long-range C-6 dispersion coefficients are presented for (3'5)Sigma(g/u), (3'5)Pi (g/u), and (1'3'5)Delta(g/u) symmetries. In addition, we analyze the role of various atomic configurations in the formation of the neon dimer. Our results can be used to model the suppression of collision-induced ionization of metastable neon, which is believed to be a good candidate for Bose-Einstein condensation. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. St Petersburg State Univ, Dept Phys, St Petersburg 198904, Russia. RP Kotochigova, S (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 29 TC 3 Z9 3 U1 0 U2 6 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2000 VL 61 IS 4 AR 042712 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 301ME UT WOS:000086313300053 ER PT J AU Musielok, J Bridges, JM Fuhr, JR Wiese, WL AF Musielok, J Bridges, JM Fuhr, JR Wiese, WL TI Transition probability ratios for selected multiplets of CI, NI, and OI, and comparisons with recent calculations SO PHYSICAL REVIEW A LA English DT Article ID SPECTROSCOPIC COUPLING SCHEME; ASTROPHYSICAL INTEREST; CARBON; TESTS AB With a wall-stabilized high-current arc,we have measured the transition probabilities of several multiplet pairs of C I, N I, and O I. Pairs have been selected for which two recent ab initio calculations have produced widely different results. All chosen multiplets are among the prominent, strong features of their respective spectra, and the pairing is in each case done for multiplets that hardly differ in their excitation energies. Our results do not favor either of the calculations, but are consistent with an earlier experiment. C1 Opole Univ, Inst Phys, PL-45052 Opole, Poland. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Musielok, J (reprint author), Opole Univ, Inst Phys, PL-45052 Opole, Poland. NR 10 TC 11 Z9 11 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2000 VL 61 IS 4 AR 044502 DI 10.1103/PhysRevA.61.044502 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 301ME UT WOS:000086313300092 ER PT J AU Torii, Y Suzuki, Y Kozuma, M Sugiura, T Kuga, T Deng, L Hagley, EW AF Torii, Y Suzuki, Y Kozuma, M Sugiura, T Kuga, T Deng, L Hagley, EW TI Mach-Zehnder Bragg interferometer for a Bose-Einstein condensate SO PHYSICAL REVIEW A LA English DT Article ID STANDING LIGHT-WAVE; ATOMS; SCATTERING; TRAP AB We construct a Mach-Zehnder interferometer using Bose-Einstein condensed rubidium atoms and optical Bragg diffraction. In contrast to interferometers based on normal diffraction, where only a small percentage of the atoms contribute to the signal, our Bragg diffraction interferometer uses all the condensate atoms. The condensate coherence properties and high phase-space density result in an interference pattern of nearly 100% contrast. The two arms of the interferometer may be completely separated in space, making it an ideal tool that can be used to detect vortices or other topological condensate phases. C1 Univ Tokyo, Inst Phys, Meguro Ku, Tokyo 1538902, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Torii, Y (reprint author), Gakushuin Univ, Dept Phys, Toshima Ku, Mejiro 1-5-1, Tokyo 1718588, Japan. RI Deng, Lu/B-3997-2012; Hagley, Edward/B-4285-2012 NR 21 TC 87 Z9 89 U1 2 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD APR PY 2000 VL 61 IS 4 AR 041602 DI 10.1103/PhysRevA.61.041602 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 301ME UT WOS:000086313300012 ER PT J AU Huang, Q Lynn, JW Erwin, RW Santoro, A Dender, DC Smolyaninova, VN Ghosh, K Greene, RL AF Huang, Q Lynn, JW Erwin, RW Santoro, A Dender, DC Smolyaninova, VN Ghosh, K Greene, RL TI Temperature and field dependence of the phase separation, structure, and magnetic ordering in La1-xCaxMnO3 (x=0.47, 0.50, and 0.53) SO PHYSICAL REVIEW B LA English DT Article ID CHARGE; LA0.5CA0.5MNO3; CROSSOVER AB Neutron-powder-diffraction measurements, combined with magnetization and resistivity data, have been carried out in the doped perovskite La1-xCxMnO3 (x=0.47, 0.50, and 0.53) to elucidate the structural, magnetic, and electronic properties of the system around the composition corresponding to an equal number of Mn3+ and Mn4+. At room temperature all three samples are paramagnetic and single phase, with crystallographic symmetry Pnma. The samples then all become ferromagnetic (FM) at T(C)approximate to 265K. At -230 K, however, a second distinct crystallographic phase (denoted A-II) begins to form. Initially the intrinsic widths of the peaks are quite large, but they narrow as the temperature decreases and the phase fraction increases, indicating microscopic coexistence. The A-II phase has the same space-group symmetry and similar lattice parameters as the initial (F-I) phase. Both phases begin to exhibit weak Jahn-Teller distortions of the MnO6 octahedra below similar to 230 K, but the distortions are different in the two phases and vary in character with temperature, and can be interpreted in terms of ordering of the d(z)(2) orbitals. The fraction of the sample that exhibits the A-II phase increases with decreasing temperature and also increases with increasing Ca doping, but the transition never goes to completion to the lowest temperatures measured (5 K), and the two phases therefore coexist in this temperature-composition regime. Phase A-II orders antiferromagnetically (AFM) below a Neel temperature T(N)approximate to 160K, with the CE-type magnetic structure. For the x=0.47 sample the proportion of FI at 10 K is about 60%, which has afforded us the opportunity to fully characterize the crystallographic and magnetic behavior of both phases over the entire temperature range. The F-I phase maintains the ferromagnetic stare for all temperatures below T-C, with the moment direction remaining along the c axis. Resistivity measurements show that this phase is a conductor, while the CE phase is insulating. Application of magnetic fields up to 9 T progressively inhibits the formation of the A-II phase, but this suppression is path dependent, being much stronger, for example, if the sample is field-cooled compared to zero-field cooling and then applying the field. The H-T phase diagram obtained from the diffraction measurements is in good agreement with the results of magnetization and resistivity. Overall the measurements underscore the delicate energetic balance between the magnetic, structural, and electronic properties of the system. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Univ Maryland, Ctr Superconduct Res, Dept Phys, College Pk, MD 20742 USA. RP Huang, Q (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 19 TC 110 Z9 113 U1 0 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 1 PY 2000 VL 61 IS 13 BP 8895 EP 8905 DI 10.1103/PhysRevB.61.8895 PG 11 WC Physics, Condensed Matter SC Physics GA 306LD UT WOS:000086597400052 ER PT J AU Chopra, HD Yang, DX Chen, PJ Parks, DC Egelhoff, WF AF Chopra, HD Yang, DX Chen, PJ Parks, DC Egelhoff, WF TI Nature of coupling and origin of coercivity in giant magnetoresistance NiO-Co-Cu-based spin valves SO PHYSICAL REVIEW B LA English DT Article ID ANTIFERROMAGNETIC INTERLAYER EXCHANGE; LAYERED MAGNETIC-STRUCTURES; ENHANCED MAGNETORESISTANCE; MULTILAYERS; SUPERLATTICES; GROWTH; FILMS; SANDWICHES; SURFACTANT AB The effect of various couplings on the switching field and coercivity in NiO-Co-Cu-based giant magnetoresistance (GMR) bottom spin valves is investigated. Bottom spin valves as well as different layer permutations that make up a bottom spin valve, viz., Co single films, Co/Cu/Co trilayers, and Co/NiO bilayers (deposited under similar growth conditions), were investigated for their magnetic, crystal, and interfacial structure. As-deposited bottom spin valves exhibit a large GMR of approximate to 16.5%, and a small net ferromagnetic coupling (+0.36 mT) between the "free" Co layer and the NiO-pinned Co layer. The high resolution transmission electron microscopy (HRTEM) and in situ scanning tunneling microscopy (STM) studies on spin valves and trilayers show that the average grain size in these films is approximate to 20 nm and average roughness approximate to 0.3 nm. Using these values, the Observed ferromagnetic coupling in spin valves could largely be accounted for by Neel's so-called "orange-peel" coupling. Results also show that the "free" Co layer exhibits an enhanced, coercivity (H-c(Free-Co) = 6.7 mT) with respect to Co single films of comparable thickness (H-c(Co) = 2.7 mT). The TEM studies did not reveal the presence of any pin-holes, and "orange-peel" or oscillatory exchange coupling mechanisms cannot adequately account for this observed coercivity enhancement in the "free" Co layer of spin valves. The present study shows that the often observed and undesirable coercivity enhancement in the "free" Co layer results from magnetostatic coupling between domain walls in the "free" Co layer and high coercivity NiO-pinned Co layer (H-c(Pinned-Co) approximate to 45 mT); without NiO, the coercivity of Co layers in the corresponding Co/Cu/Co trilayer remains largely unchanged (H-c(Co/Cu/Co) = 3.0 mT) with respect to Co single films, Evidence of: magnetostatically coupled domain walls was confirmed by direct observation of magnetization reversal, which revealed that domain walls in the "free" Co layer are magnetostatically locked-in with stray fields due to domain walls or magnetization ripples in the high coercivity NiO-pinned Co layer of the spin valves. The observed escape fields (defined as fields in excess of intrinsic coercivity of Co single him that are required to overcome magnetostatic coupling between domain walls) are in agreement with theoretically calculated values of escape fields. C1 SUNY Buffalo, Thin Films & Nanosynth Lab, Mat Program, Dept Aerosp & Mech Engn, Buffalo, NY 14260 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Chopra, HD (reprint author), SUNY Buffalo, Thin Films & Nanosynth Lab, Mat Program, Dept Aerosp & Mech Engn, Buffalo, NY 14260 USA. EM hchopra@eng.buffalo.edu NR 49 TC 63 Z9 64 U1 1 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 APR 1 PY 2000 VL 61 IS 14 BP 9642 EP 9652 DI 10.1103/PhysRevB.61.9642 PG 11 WC Physics, Condensed Matter SC Physics GA 303TW UT WOS:000086441800061 ER PT J AU Coursey, BM Nath, R AF Coursey, BM Nath, R TI Radionuclide therapy SO PHYSICS TODAY LA English DT Article ID DOSIMETRY C1 Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. Yale Univ, Div Radiol Phys, New Haven, CT 06520 USA. RP Coursey, BM (reprint author), Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. NR 15 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD APR PY 2000 VL 53 IS 4 BP 25 EP 30 DI 10.1063/1.883033 PG 6 WC Physics, Multidisciplinary SC Physics GA 299GN UT WOS:000086190800012 ER PT J AU Glotzer, SC AF Glotzer, SC TI Colloids reinforce glass theory SO PHYSICS WORLD LA English DT Article C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Glotzer, SC (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 0 TC 8 Z9 8 U1 0 U2 4 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 APR PY 2000 VL 13 IS 4 BP 22 EP 23 PG 2 WC Physics, Multidisciplinary SC Physics GA 456TF UT WOS:000170097800021 ER PT J AU Armstrong, TN Cronin, TW Bradley, BP AF Armstrong, TN Cronin, TW Bradley, BP TI Microspectrophotometric analysis of intact chromatophores of the Japanese medaka, Oryzias latipes SO PIGMENT CELL RESEARCH LA English DT Article ID NORTHERN ANCHOVY; ENGRAULIS-MORDAX; MELANOMA-CELLS; DNA-DAMAGE; IRRADIATION; WAVELENGTHS; RADIATION; SURVIVAL; SOLAR AB To investigate the possible photoprotective role of chromatophores in fish, the absorbances of four types of intact chromatophores in adult and larval Japanese medaka mere analyzed using microspectrophotometric techniques. The absorbance spectrum of each chromatophore class was obtained from 300 to 550 nm. The absorbance spectra of intact leucophores, melanophores and xanthophores were very similar to the published absorbance spectra of the isolated pure pigments contained in each chromatophore type, pteridines, melanin and carotenoids or pteridines, respectively. Based on these absorbance spectra, leucophores and melanophores should provide the most ultraviolet CUV) photoprotection to fish since the compounds they contain, pteridines and melanin, correspondingly, have strong absorbances in the UV region of the spectrum. Xanthophores containing carotenoids are not likely to provide much protection to fish from UV-induced damage since carotenoids have low absorbances in the UV range. Xanthophores containing colored pteridines, however, may provide somewhat greater UV protection to fish, since pteridines absorb more light than carotenoids in the UV portion of the spectrum. The relative frequency, coverage and thickness of these two types of xanthophores should determine how much protection xanthophores as a chromatophore type mould provide against W-induced damage. C1 Univ Maryland, Dept Biol Sci, Baltimore, MD 21201 USA. RP Armstrong, TN (reprint author), NOAA, Natl Ocean Serv, Natl Ctr Coastal Ocean Sci, 1305 East West Highway,Room 9224, Silver Spring, MD 20910 USA. NR 26 TC 8 Z9 9 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0893-5785 J9 PIGM CELL RES JI Pigm. Cell. Res. PD APR PY 2000 VL 13 IS 2 BP 116 EP 119 DI 10.1034/j.1600-0749.2000.130210.x PG 4 WC Cell Biology; Dermatology SC Cell Biology; Dermatology GA 318HM UT WOS:000087277900009 PM 10841033 ER PT J AU Chou, KF Han, CC Lee, S AF Chou, KF Han, CC Lee, S TI Water transport in crosslinked 2-hydroxyethyl methacrylate SO POLYMER ENGINEERING AND SCIENCE LA English DT Article ID CASE-II DIFFUSION; POLY(2-HYDROXYETHYL METHACRYLATE); MECHANICAL DEFORMATION; SYNTHETIC HYDROGELS; METHANOL TRANSPORT; GLASSY POLYMERS; POLYIMIDE FILMS; SORPTION; VAPOR; CONDUCTIVITY AB Water transport in crosslinked a-hydroxyethyl methacrylate (HEMA) was investigated. Crosslinked HEMA was irradiated by gamma ray in vacuum for this study. The sorption data of de-ionized water transport in crosslinked HEMA subjected to various gamma ray dosages are in excellent agreement with Harmon's model which accounts for Case I, Case II, as well as the anomalous transport processes. The diffusion coefficient for Case I transport and velocity for Case II transport satisfy the Arrhenius equation for all dosages. The transport process was exothermic and the equilibrium-swelling ratio satisfied the van't Hoff plot. The pH value of de-ionized water after the sorption/de-sorption treatment of the irradiated crosslinked HEMA specimen was analyzed. The transmittance of irradiated crosslinked HEMA treated by de-ionized water was also studied. The effect of irradiation on the polymer chains was revealed by the measurement of glass transition temperature and the quantitative determination of water structures in crosslinked HEMA hydrogel. The UV cut-oil wavelength of crosslinked HEMA shifted to longer wavelength side with increasing irradiation dosage, but the trend of transmittance after water treatment was opposite. The effect of specimen thickness on water transport was also studied. C1 Natl Tsing Hua Univ, Dept Mat Sci, Hsinchu, Taiwan. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Chou, KF (reprint author), Natl Tsing Hua Univ, Dept Mat Sci, Hsinchu, Taiwan. NR 51 TC 7 Z9 8 U1 0 U2 7 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD APR PY 2000 VL 40 IS 4 BP 1004 EP 1014 DI 10.1002/pen.11228 PG 11 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 309GE UT WOS:000086759300016 ER PT J AU Schmitz, T Ziegert, J AF Schmitz, T Ziegert, J TI Dynamic evaluation of spatial CNC contouring accuracy SO PRECISION ENGINEERING-JOURNAL OF THE INTERNATIONAL SOCIETIES FOR PRECISION ENGINEERING AND NANOTECHNOLOGY LA English DT Article DE spatial metrology; dynamic path measurement; contouring errors; laser ball bar ID MACHINE-TOOL METROLOGY; ERROR AB An instrument capable of measuring arbitrary, dynamic CNC tool paths through three-dimensional space with micrometer-level accuracy is developed and tested. The instrument uses three Laser Ball Bars simultaneously (i.e., simultaneous trilateration) to allow for dynamic path measurements. The design of the instrument is described. The performance is verified by static repeatability testing, comparison with an independent measurement system, and comparison with the dimensions of machined parts. The instrument is demonstrated to be capable of measurement of arbitrary three dimensional tool paths with near micron level accuracy. Published by Elsevier Science Inc. C1 Univ Florida, Dept Mech Engn, Gainesville, FL 32611 USA. Natl Inst Stand & Technol, Automated Prod Technol Div, Mfg Engn Lab, Gaithersburg, MD 20899 USA. RP Ziegert, J (reprint author), Univ Florida, Dept Mech Engn, Gainesville, FL 32611 USA. NR 14 TC 11 Z9 13 U1 1 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Int. Soc. Precis. Eng. Nanotechnol. PD APR PY 2000 VL 24 IS 2 BP 99 EP 118 DI 10.1016/S0141-6359(99)00034-3 PG 20 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA 336ET UT WOS:000088289500001 ER PT J AU Redelsperger, JL Brown, PRA Guichard, F Hoff, C Kawasima, M Lang, S Montmerle, T Nakamura, K Saito, K Seman, C Tao, WK Donner, LJ AF Redelsperger, JL Brown, PRA Guichard, F Hoff, C Kawasima, M Lang, S Montmerle, T Nakamura, K Saito, K Seman, C Tao, WK Donner, LJ TI A GCSS model intercomparison for a tropical squall line observed during TOGA-COARE. I: Cloud-resolving models SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE cloud-resolving models; clouds; Doppler radar; GCSS ID MESOSCALE CONVECTIVE SYSTEM; DOPPLER RADAR DATA; 3-DIMENSIONAL SIMULATION; NUMERICAL-SIMULATION; LONGWAVE RADIATION; STRATIFORM REGION; EVOLUTION; SENSITIVITY; MOMENTUM; PARAMETERIZATION AB Results from eight cloud-resolving models are compared for the first time for the case of an oceanic tropicalsquall line observed during the Tropical Ocean/Global Atmosphere Coupled Ocean-Atmosphere Response Experiment. There is broad agreement between all the models in describing the overall structure and propagation of the squall line and some quantitative agreement in the evolution of rainfall. There is also a more qualitative agreement between the models in describing the vertical structure of the apparent heat and moisture sources. The three-dimensional (3D) experiments with an active ice phase and open lateral boundary conditions along the direction of the system propagation show good agreement for all parameters. The comparison of 3D simulated fields with those obtained from two different analyses of airborne Doppler radar data indicates that the 3D models are able to simulate the dynamical structure of the squall line, including the observed double-peaked updraughts. However, the second updraught peak at around 10 km in height is obtained only when the ice phase is represented. The 2D simulations with an ice-phase parametrization also exhibit this structure, although with a larger temporal variability. In the 3D simulations, the evolution of the mean wind profile is in the sense of decreasing the shear, but the 2D simulations are unable to reproduce this behaviour. C1 Inst Low Temp Sci, Tsukuba, Ibaraki, Japan. Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ctr Etud Environm Terr & Planetaires, Velizy Villacoubl, France. Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Redelsperger, JL (reprint author), CNRS, CNRM, GAME, 42 Av Coriolis, F-31057 Toulouse, France. RI Kawashima, Masayuki/D-9107-2012; Brown, Philip/D-9819-2013; Jean-Luc, Redelsperger/L-4021-2015 OI Brown, Philip/0000-0003-4643-4923; NR 48 TC 87 Z9 88 U1 1 U2 4 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD APR PY 2000 VL 126 IS 564 BP 823 EP 863 DI 10.1256/smsqj.56403 PN A PG 41 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 314LT UT WOS:000087057900003 ER PT J AU Tassey, G AF Tassey, G TI Standardization in technology-based markets SO RESEARCH POLICY LA English DT Article DE standardization; innovation; R&D; economic growth; industry structure ID ARCHITECTURE AB The complexity of modern technology, especially its system character, has led to an increase in the number and variety of standards that affect a single industry or market. Standards affect the R&D, production, and market penetration stages of economic activity and therefore have a significant collective effect on innovation, productivity, and market structure. Standards are classified into product-element and nonproduct categories because the two types arise from different technologies and require different formulation and implementation strategies. Because standards are a form of technical infrastructure, they have considerable public good content. Research policy must therefore include standardization in analyses of technology-based growth issues. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, ADMIN 1000, Program Off, Gaithersburg, MD 20899 USA. RP Tassey, G (reprint author), Natl Inst Stand & Technol, ADMIN 1000, Program Off, Gaithersburg, MD 20899 USA. NR 23 TC 104 Z9 110 U1 4 U2 29 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-7333 J9 RES POLICY JI Res. Policy PD APR PY 2000 VL 29 IS 4-5 BP 587 EP 602 DI 10.1016/S0048-7333(99)00091-8 PG 16 WC Management; Planning & Development SC Business & Economics; Public Administration GA 309BE UT WOS:000086746700009 ER PT J AU Lee, S Hoobler, RJ Leone, SR AF Lee, S Hoobler, RJ Leone, SR TI A pulsed Laval nozzle apparatus with laser ionization mass spectroscopy for direct measurements of rate coefficients at low temperatures with condensable gases SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID ION-MOLECULE REACTIONS; KINETICS; DESIGN; CRESU; UF6; SPECTROMETRY; CLUSTERS; SI(100); BEAM; CH4 AB A pulsed Laval nozzle, low Mach number supersonic expansion kinetics apparatus has been constructed to study neutral-neutral kinetics by a rather general laser photolysis initiation and laser photoionization detection of the product species. This new apparatus permits laboratory studies of low temperature rate coefficients (e.g., 70-170 K) on condensable gases that have insufficient vapor pressures at low temperatures for conventional methods of kinetic measurements. The design considerations, the uniformity of the reaction zone over 10-20 cm, and the skimmer sampling of the pulsed Laval expansion are examined. The direct measurement of a rate coefficient at 90 K is also demonstrated using this new apparatus. (C) 2000 American Institute of Physics. [S0034-6748(00)04104-6]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Quantum Phys Div, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Quantum Phys Div, Boulder, CO 80309 USA. NR 30 TC 41 Z9 41 U1 2 U2 26 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 APR PY 2000 VL 71 IS 4 BP 1816 EP 1823 DI 10.1063/1.1150542 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 301ET UT WOS:000086296600042 ER PT J AU Ravikiran, A Low, TS AF Ravikiran, A Low, TS TI Estimation of lubricant thickness on a magnetic hard disk using acoustic emission SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB In this note we describe a simple and relatively inexpensive method to estimate lubricant thickness on a magnetic hard disk by making use of the acoustic emission generated at the head-disk interface during sliding in a contact start stop tester. (C) 2000 American Institute of Physics. [S0034-6748(00)03104-X]. C1 Natl Univ Singapore, Dept Elect Engn, Singapore 119260, Singapore. Natl Univ Singapore, Data Storage Inst, Singapore 119260, Singapore. RP Ravikiran, A (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 2000 VL 71 IS 4 BP 1915 EP 1916 DI 10.1063/1.1150552 PG 2 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 301ET UT WOS:000086296600060 ER PT J AU Mohr, PJ Taylor, BN AF Mohr, PJ Taylor, BN TI CODATA recommended values of the fundamental physical constants: 1998 SO REVIEWS OF MODERN PHYSICS LA English DT Review ID ANOMALOUS MAGNETIC-MOMENT; QUANTIZED HALL RESISTANCE; FINE-STRUCTURE CONSTANT; VACUUM-POLARIZATION CONTRIBUTION; HIGH-RESOLUTION SPECTROSCOPY; DEUTERON BINDING-ENERGY; NEWTONIAN GRAVITATIONAL CONSTANT; PROTON GYROMAGNETIC RATIO; X-RAY INTERFEROMETRY; ABSOLUTE FREQUENCY-MEASUREMENT AB This paper gives the 1998 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. Further, it describes in detail the adjustment of the values of the subset of constants on which the complete 1998 set of recommended values is based. The 1998 set replaces its immediate predecessor recommended by CODATA in 1986. The new adjustment, which takes into account all of the data available through 31 December 1998, is a significant advance over its 1986 counterpart. The standard uncertainties (i.e., estimated standard deviations) of the new recommended values are in most cases about 1/5 to 1/12 and in some cases 1/160 times the standard uncertainties of the corresponding 1986 values. Moreover, in almost all cases the absolute values of the differences between the 1998 values and the corresponding 1986 values are less than twice the standard uncertainties of the 1986 values. The new set of recommended values is available on the World Wide Web at physics.nist.gov/constants. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM peter.mohr@nist.gov; barry.taylor@nist.gov NR 685 TC 637 Z9 646 U1 1 U2 29 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 EI 1539-0756 J9 REV MOD PHYS JI Rev. Mod. Phys. PD APR PY 2000 VL 72 IS 2 BP 351 EP 495 DI 10.1103/RevModPhys.72.351 PG 145 WC Physics, Multidisciplinary SC Physics GA 315TH UT WOS:000087128700003 ER PT J AU Wuensch, BJ Eberman, KW Heremans, C Ku, EM Onnerud, P Yeo, EME Haile, SM Stalick, JK Jorgensen, JD AF Wuensch, BJ Eberman, KW Heremans, C Ku, EM Onnerud, P Yeo, EME Haile, SM Stalick, JK Jorgensen, JD TI Connection between oxygen-ion conductivity of pyrochlore fuel-cell materials and structural change with composition and temperature SO SOLID STATE IONICS LA English DT Article DE fuel cell materials; oxygen fast-ion conduction; X-ray and neutron Rietveld analysis; pyrochlore oxide solid solutions; independent order-disorder of cations and anions ID SOLID-SOLUTIONS; FLUORITE; DISORDER; OXIDES; TRENDS AB Oxides are believed to assume the A(2)B(2)O(7) pyrochlore structure type for a specific range of ratios of the cation radii, R(A)/R(B). Substitution of a larger B' ion in solid solution for B can progressively drive the system to complete disorder as in Y(2)(Zr(y) Ti(1-y))(2)O(7), producing an oxygen-ion conductivity, sigma greater than 10(-2) S/cm at 1000 degrees C. comparable to the values of 10(-1) S/cm found for M(3+)-stabilized cubic zirconias. Rietveld analyses of neutron and X-ray powder diffraction data have been employed to obtain structural data for the related systems Y(2)(Sn(y)Ti(1-y))(2)O(7), Y(2)(Zr(y)Sn(1-y))(2)O(7), Gd(2)(Sn(y)Ti(1-y))(2)O(7) and (Sc(z)Yb(1-z))(2)Ti(2)O(7) to test whether the state of disorder and attendant ionic conductivity are indeed determined by R(A)/(R(B),R(B)) This was not the case for the Sn-Ti solid solutions: they retained an ordered pyrochlore structure for all values of y, The slight variation of ionic conductivity (less than one order of magnitude with a maximum in sigma at intermediate y) was successfully explained by the structural data. The behavior of Y(2)(Zr(y)Sn(1-y))(2)O(7) solid solutions was very similar to that of the Zr-Ti phases. Neutron powder diffraction profiles were recorded as fully-ordered Y(2)Sn(2)O(7) and highly-disordered Y(2)(Zr(0.6)Ti(0.4))(2)O(7) were heated in situ at temperatures in the range 20-1500 degrees C. The structure of Y(2)Sn(2)O(7) steadfastly remained fully-ordered over this temperature range. The principal change in the structure was increase in the positional coordinate, x, for O(1), corresponding to increased distortion of the oxygen-ion array as temperature was increased, a consequence of greater thermal expansion of the A(3-)-O bond relative to change in the B(4+)-O separation. The highly-disordered cation arrangements in Y(2)(Zr(0.6)Ti(0.4))(2)O(7) remain unchanged up to 1250 degrees C when the oxygen array began to undergo further disorder. The same anion site occupancies were observed during heating and cooling cycles suggesting that their distribution does represent an equilibrium state. (C) 2000 Elsevier Science B.V, All rights reserved. C1 MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP Wuensch, BJ (reprint author), MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RI Haile, Sossina/I-3448-2015 NR 44 TC 253 Z9 262 U1 2 U2 61 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2738 J9 SOLID STATE IONICS JI Solid State Ion. PD APR PY 2000 VL 129 IS 1-4 BP 111 EP 133 DI 10.1016/S0167-2738(99)00320-3 PG 23 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 302DG UT WOS:000086349700010 ER PT J AU Raes, F Bates, T McGovern, F Van Liedekerke, M AF Raes, F Bates, T McGovern, F Van Liedekerke, M TI The 2nd Aerosol Characterization Experiment (ACE-2): general overview and main results SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Editorial Material ID MARINE BOUNDARY-LAYER; ATLANTIC; NUMBER AB This overview summarizes the objectives of the Aerosol Characterization Experiments (ACEs) of the International Global Atmospheric Chemistry (IGAC) project and the research strategy implemented in the second of this series of experiments (ACE-2). ACE-2 took place from 16 June to 24 July 1997, over the sub-tropical North-East Atlantic. It provided an opportunity to study the properties, processes and effects of contrasting aerosol types in this region, including background marine and anthropogenic pollution aerosol in the marine boundary layer (MBL), and background aerosol and mineral dust in the overlaying free troposphere (FT). The major achievements of ACE-2 include: (a) identification of entrainment, in-cloud scavenging and coagulation as the major processes transforming a pollution aerosol transported within the MEL; (b) the first documentation of the indirect radiative effect of aerosols at the scale of a cloud ensemble in continental pollution outflow; (c) observation of a wide range in the contribution of organic material to the sub-micron aerosol mass, with possibly the highest contribution in the Free tropospheric; (d) improved understanding of the role of condensing HCl, HNO3 and NH3 as a growth mechanism of sub-micron aerosols in polluted air masses advecting over the ocean. A close connection was observed between meteorological factors (such as horizontal and vertical wind speed, boundary layer development, entrainment, humidity fields) and aerosol and cloud characteristics. in the ACE-2 region, these meteorological factors, rather than aerosol microphysics and chemistry. often dominated the shaping of the aerosol size distribution and/or their effect on radiation and clouds. The ACE-2 data presently analyzed provide a qualitative, and in many cases a quantitative understanding of the complex gas/aerosol/cloud system in the sub-tropical marine environment. This will guide future model development. Some major data sets are still to be analyzed. C1 Commiss European Communities, Joint Res Ctr, Inst Environm, I-21020 Ispra, VA, Italy. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Commiss European Communities, Joint Res Ctr, Inst Environm, I-21020 Ispra, VA, Italy. EM frank.raes@jrc.it RI Bates, Timothy/L-6080-2016 NR 47 TC 217 Z9 224 U1 2 U2 17 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 EI 1600-0889 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 111 EP 125 DI 10.1034/j.1600-0889.2000.00124.x PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900002 ER PT J AU Schmeling, M Russell, LM Erlick, C Collins, DR Jonsson, H Wang, Q Kregsamer, P Streli, C AF Schmeling, M Russell, LM Erlick, C Collins, DR Jonsson, H Wang, Q Kregsamer, P Streli, C TI Aerosol particle chemical characteristics measured from aircraft in the lower troposphere during ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID EXPERIMENT MARINE AEROSOL; SEA-SALT SULFATE; SIZE DISTRIBUTIONS; PARTICULATE MATTER; OPTICAL-CONSTANTS; MINERAL AEROSOL; ATLANTIC-OCEAN; BOUNDARY-LAYER; SOURCE-REGIONS; AFRICAN DUST AB During the Aerosol Characterization Experiment (ACE-2), filter samples were collected aboard the Center For Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Pelican aircraft near Tenerife in June and July of 1997. The flights included constant altitude measurements in the boundary layer as well as profiles up to 3800 m providing detailed chemical information about the composition of the aerosol distribution in the lower troposphere. Three cases with different air mass origins - clean marine air, anthropogenically-influenced air from the European continent, and dust-laden air from the Sahara - were identified. The samples were analyzed by ion chromatography (IC) for ionic species, by combined thermal and optical analysis (TOA) for organic carbon, and by total reflection X-ray fluorescence (TXRF) for elemental composition. Particle composition and size distributions For the range of air masses encountered illustrate links in the chemical and microphysical characteristics of aerosol From different sources. Clean marine air masses were characterized by low particle number and mass concentrations with no detectable metals, while anthropogenically-influenced and dust-laden air had high number, mass, and trace metal concentrations. Anthropogenic sources were characterized by high concentrations of submicron particles and some Fe and Cu, whereas dust particle loadings included a significant mass of micron-sized particles and significant loadings of Fe, in addition to small amounts of Mn, Cu, and Ni. These results showed similar tracers for air mass origin as those found in other measurements of oceanic and continental air masses. Aerosol optical properties were estimated with a simplified model of the aerosol based on the measured compositions. The real and imaginary refractive indices and single scattering albedos differed significantly among the three types of aerosol measured, with clean marine aerosol properties showing the least absorption and dust-containing aerosols showing the most. There were only small differences in optical properties for the two different cases of clean marine aerosol, but some significant differences between the two dust cases. Since measurement uncertainties affect these calculations, we studied the type of mixing and the fraction of absorbing species and found the calculation was sensitive to these variations only for the dust-containing aerosol case, probably due to the small amount of water present. While the optical properties varied little with composition for clean marine and anthropogenically-influenced cases, they showed a strong dependence on variations in particle composition and mixing state for the dust-containing cases. C1 Princeton Univ, Dept Chem Engn, Princeton, NJ 08544 USA. Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. CALTECH, Dept Chem Engn, Pasadena, CA 91125 USA. USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. Austrian Univ, Atominst, Vienna, Austria. RP Russell, LM (reprint author), Princeton Univ, Dept Chem Engn, A317 Engn Quadrangle, Princeton, NJ 08544 USA. RI Collins, Don/F-9617-2012; OI Streli, Christina/0000-0002-5141-3177 NR 42 TC 20 Z9 20 U1 0 U2 9 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 185 EP 200 DI 10.1034/j.1600-0889.2000.00007.x PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900006 ER PT J AU Novakov, T Bates, TS Quinn, PK AF Novakov, T Bates, TS Quinn, PK TI Shipboard measurements of concentrations and properties of carbonaceous aerosols during ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID DIFFUSION DENUDER SAMPLER; CLOUD-CONDENSATION-NUCLEI; BIOMASS SMOKE PARTICLES; UNITED-STATES; ATTENUATION; EXTINCTION; FILTERS; AMBIENT; SULFATE; SOOT AB Mass concentrations of total, organic and black carbon were derived by analyzing the super-micron and submicron aerosol fractions of shipboard collected samples in the eastern Atlantic Ocean as part of the second Aerosol Characterization Experiment (ACE-2). These analyses were complemented by experiments intended to estimate the water-soluble fraction of the submicron carbonaceous material. Our results can be summarized as follows. Depending on the sample, between 35% and 80% of total aerosol carbon is associated with the submicron fraction. Total submicron carbon was well correlated with black carbon, a unique tracer for incomplete combustion. These correlations and the approximately constant total to black carbon ratios, suggest that the majority of submicron total carbon is of primary combustion derived origin. No systematic relationship between total submicron aerosol carbon and sulfate concentrations was found. Sulfate concentrations were, with a few exceptions, significantly higher than total carbon. Our experiments have demonstrated that water exposure removed between 36% and 72% of total carbon from the front filter, suggesting that a substantial fraction of the total submicron aerosol organic carbon is water-soluble. An unexpected result of this study is that water exposure of filter samples caused substantial removal of, nominally insoluble, submicron black carbon. Possible reasons for this observation are discussed. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, Berkeley, CA 94720 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Novakov, T (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Environm Energy Technol Div, 1 Cyclotron Rd,MS-73, Berkeley, CA 94720 USA. RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 26 TC 40 Z9 43 U1 0 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 228 EP 238 DI 10.1034/j.1600-0889.2000.00019.x PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900008 ER PT J AU Quinn, PK Bates, TS Coffman, DJ Miller, TL Johnson, JE Covert, DS Putaud, JP Neususs, C Novakov, T AF Quinn, PK Bates, TS Coffman, DJ Miller, TL Johnson, JE Covert, DS Putaud, JP Neususs, C Novakov, T TI A comparison of aerosol chemical and optical properties from the 1st and 2nd Aerosol Characterization Experiments SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID CHARACTERIZATION EXPERIMENT ACE-1; MARINE BOUNDARY-LAYER; SULFUR CYCLE; SEA-SALT; SIZE DISTRIBUTION; METHANESULFONATE; ATMOSPHERE; CHLORIDE; ATLANTIC; AMMONIA AB Shipboard measurements of aerosol chemical composition and optical properties were made during both ACE-1 and ACE-2, ACE-1 focused on remote marine aerosol minimally perturbed by continental sources. ACE-2 studied the outflow of European aerosol into the NE Atlantic atmosphere. A variety of air masses were sampled during ACE-2 including Atlantic, polar, Iberian Peninsula, Mediterranean, and Western European. Reported here are mass size distributions of non-sea salt (nss) sulfate, sea salt, and methanesulfonate and submicron and supermicron concentrations of black and organic carbon. Optical parameters include submicron and supermicron aerosol scattering and backscattering coefficients at 550 nm, the absorption coefficient at 550 +/- 20 nm, the Angstrom exponent for the 550 and 700 nm wavelength pair, and single scattering albedo at 550 nm. All data are reported at the measurement relative humidity of 55%. Measured concentrations of nss sulfate aerosol indicate that, relative to ACE-1, ACE-2 aerosol during both marine and continental flow was impacted by continental sources. Thus, while sea salt controlled the aerosol chemical composition and optical properties of both the submicron and supermicron aerosol during ACE-1, it played a relatively smaller role in ACE-2. This is confirmed by the larger average Angstrom exponent for ACE-2 continental aerosol of 1.2 +/- 0.26 compared to the ACE-1 average of -0.03 +/- 0.38. The depletion of chloride from sea salt aerosol in ACE-2 continental air masses averaged 55 +/- 25% over all particle sizes. This compares to the ACE-2 marine average of 4.8 +/- 18% and indicates the enhanced interaction of anthropogenic acids with sea salt as continental air masses are transported into the marine atmosphere. Single scattering albedos averaged 0.95 +/- 0.03 for ACE-2 continental air masses. Averages for ACE-2 and ACE-1 marine air masses were 0.98 +/- 0.01 and 0.99 +/- 0.01, respectively. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA 98195 USA. Commiss European Communities, Joint Res Ctr, Inst Environm, I-21020 Ispra, Italy. Inst Tropospher Res, D-04303 Leipzig, Germany. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. RP Quinn, PK (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 32 TC 74 Z9 79 U1 1 U2 11 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 239 EP 257 DI 10.1034/j.1600-0889.2000.00033.x PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900009 ER PT J AU Bates, TS Quinn, PK Covert, DS Coffman, DJ Johnson, JE Wiedensohler, A AF Bates, TS Quinn, PK Covert, DS Coffman, DJ Johnson, JE Wiedensohler, A TI Aerosol physical properties and processes in the lower marine boundary layer: a comparison of shipboard sub-micron data from ACE-1 and ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID NUMBER SIZE DISTRIBUTIONS; CLOUD CONDENSATION NUCLEI; PARTICLE NUCLEATION; SEA-SALT; ATMOSPHERIC NUCLEI; NORTHEAST ATLANTIC; OPTICAL-PROPERTIES; MACQUARIE ISLAND; PACIFIC; SUMMER AB The goals of the IGAC Aerosol Characterization Experiments (ACE) are to determine and understand the properties and controlling processes of the aerosol in a globally representative range of natural and anthropogenically perturbed environments. ACE-1 was conducted in the remote marine atmosphere south of Australia while ACE-2 was conducted in the anthropogenically modified atmosphere of the Eastern North Atlantic. In-situ shipboard measurements from the RV Discoverer (ACE-1) and the RV Professor Vodyanitskiy (ACE-2), combined with calculated back trajectories can be used to define the physical properties of the sub-micron aerosol in marine boundary layer (MBL) air masses from the remote Southern Ocean, Western Europe, the Iberian coast, the Mediterranean and the background Atlantic Ocean. The differences in these aerosol properties, combined with dimethylsulfide, sulfur dioxide and meteorological measurements provide a means to assess processes that affect the aerosol distribution. The background sub-micron aerosol measured over the Atlantic Ocean during ACE-2 was more abundant (number and volume) and appeared to be more aged than that measured over the Southern Ocean during ACE-1. Based on seawater DMS measurements and wind speed, the oceanic source of non-sea-salt sulfur and sea-salt to the background marine atmosphere during ACE-1 and ACE-2 was similar. However, the synoptic meteorological pattern was quite different during ACE-1 and ACE-2 The frequent frontal passages during ACE-1 resulted in the mixing of nucleation mode particles into the marine boundary layer from the free troposphere and relatively short aerosol residence times. In the more stable meteorological setting of ACE-2, a significant nucleation mode aerosol was observed in the MBL only for a half day period associated with a weak frontal system. As a result of the longer MBL aerosol residence times, the average background ACE-2 accumulation mode aerosol had a larger diameter and higher number concentration than during ACE-1. The sub-micron aerosol number size distributions in the air masses that passed over Western Europe, the Mediterranean, and coastal Portugal were distinctly different from each other and the background aerosol. The differences can be attributed to the age of the air mass and the degree of cloud processing. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA 98195 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Inst Tropospher Res, Leipzig, Germany. RP Bates, TS (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 58 TC 60 Z9 62 U1 2 U2 15 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 258 EP 272 DI 10.1034/j.1600-0889.2000.00021.x PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900010 ER PT J AU Johnson, DW Osborne, S Wood, R Suhre, K Johnson, R Businger, S Quinn, PK Wiedensohler, A Durkee, PA Russell, LM Andreae, MO O'Dowd, C Noone, KJ Bandy, B Rudolph, J Rapsomanikis, S AF Johnson, DW Osborne, S Wood, R Suhre, K Johnson, R Businger, S Quinn, PK Wiedensohler, A Durkee, PA Russell, LM Andreae, MO O'Dowd, C Noone, KJ Bandy, B Rudolph, J Rapsomanikis, S TI An overview of the Lagrangian experiments undertaken during the North Atlantic regional Aerosol Characterisation Experiment (ACE-2) SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID MARINE BOUNDARY-LAYER; STRATOCUMULUS TRANSITION EXPERIMENT; SEA-SALT; 3-DIMENSIONAL MODEL; PARTICLE-PRODUCTION; WARM STRATOCUMULUS; SULFATE AEROSOLS; CUMULUS CLOUDS; SULFUR; CLIMATE AB One of the primary aims of the North Atlantic regional Aerosol Characterisation Experiment (ACE-2) was to quantify the physical and chemical processes affecting the evolution of the major aerosol types over the North Atlantic. The best, practical way of doing this is in a Lagrangian framework where a parcel of air is sampled over several tens of hours and its physical and chemical properties are intensively measured. During the intensive observational phase of ACE-2, between 15 June 1997 and 24 July 1997, 3 cloudy Lagrangian experiments and 3 cloud-free, Lagrangian experiments were undertaken between the south west tip of the Iberian Peninsula and the Canary Islands. This paper gives an overview of the aims and logistics of all of the Lagrangian experiments and compares and contrasts them to provide a framework for the more focused Lagrangian papers in this issue and future process modelling studies and parametrisation development. The characteristics of the cloudy Lagrangian experiments were remarkably different, enabling a wide range of different physical and chemical processes to be studied. In the 1st Lagrangian, a clean maritime air mass was sampled in which salt particle production, due to increased wind speed, dominated the change in the accumulation mode concentrations. In the 2nd Lagrangian, extensive cloud cover resulted in cloud processing of the aerosol in a polluted air mass, and entrainment of air from the free troposphere influenced the overall decrease in aerosol concentrations in the marine boundary layer (MBL). Very little change in aerosol characteristics was measured in the 3rd Lagrangian, where the pollution in the MBL was continually being topped up by entraining air from a residual continental boundary layer (CBL) above. From the analysis of all the Lagrangian experiments, it has been possible to formulate, and present here, a generalised description of a European continental outbreak of pollution over the sub-tropical North Atlantic. C1 DERA, Farnborough GU14 0LX, Hants, England. Univ Toulouse, CNRM, Toulouse, France. NOAA, ARL, Idaho Falls, ID USA. Univ Hawaii, Honolulu, HI 96822 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. IFT, Leipzig, Germany. NPS, CIRPAS, Monterey, CA USA. Princeton Univ, Princeton, NJ 08544 USA. Max Planck Inst Chem, D-55128 Mainz, Germany. Univ Sunderland, CMAS, Sunderland SR2 7EE, Durham, England. Univ Stockholm, MISU, S-10691 Stockholm, Sweden. Univ E Anglia, Norwich NR4 7TJ, Norfolk, England. York Univ, N York, ON M3J 1P3, Canada. Democritus Univ Thrace, Komotini 69100, Greece. RP DERA, Bldg Y46, Farnborough GU14 0LX, Hants, England. EM dwjohnson@meto.gov.uk RI Wood, Robert/A-2989-2008; O'Dowd , Colin/K-8904-2012; Andreae, Meinrat/B-1068-2008; Quinn, Patricia/R-1493-2016; OI Wood, Robert/0000-0002-1401-3828; O'Dowd , Colin/0000-0002-3068-2212; Andreae, Meinrat/0000-0003-1968-7925; Quinn, Patricia/0000-0003-0337-4895; RAPSOMANIKIS, SPYRIDON/0000-0002-7883-0894; Suhre, Karsten/0000-0001-9638-3912 NR 68 TC 66 Z9 67 U1 1 U2 7 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 EI 1600-0889 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 290 EP 320 DI 10.1034/j.1600-0889.2000.00057.x PG 31 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900012 ER PT J AU Johnson, R Businger, S Baerman, A AF Johnson, R Businger, S Baerman, A TI Lagrangian air mass tracking with smart balloons during ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID AEROSOL; COLUMN AB A 3rd-generation smart balloon designed at National Oceanic and Atmospheric Administration, Air Resources Laboratory Field Research Division, in collaboration with the University of Hawaii, was released from ship-board during the recent Second Aerosol Characterization Experiment (ACE-2) to provide Lagrangian air-mass tracking data. ACE-2 is the 3rd in a series of field experiments designed to study the chemical, physical, and radiative properties and processes of atmospheric aerosols and their role in climate and is organized by the international global atmospheric chemistry (IGAC) program. The adjective small in the title of this paper refers to the fact that the buoyancy of the balloon automatically adjusts through the act of pumping air into or releasing air from the ballast portion of the balloon when it travels vertically outside a barometric pressure range set prior to release. The smart balloon design provides GPS location, barometric pressure, temperature, relative humidity, and other data via a transponder to a C130 research aircraft flying in the vicinity of the balloon. The addition of 2-way communication allows interactive control of the balloon operating parameters by an observer. A total of 3 cloudy Lagrangian experiments were conducted during the ACE-2 held program which lasted from 16 June through 26 July 1997. This paper reviews the design and capability of the smart balloons and their performance during the ACE-2 Lagrangian experiments. Future development and applications of the technology are discussed. C1 Univ Hawaii, Dept Meteorol, Honolulu, HI 96822 USA. NOAA, Air Resources Lab, Field Res Div, Idaho Falls, ID 83402 USA. RP Businger, S (reprint author), Univ Hawaii, Dept Meteorol, 2525 Correa Rd, Honolulu, HI 96822 USA. NR 15 TC 18 Z9 18 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 321 EP 334 DI 10.1034/j.1600-0889.2000.00034.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900013 ER PT J AU Johnson, DW Osborne, S Wood, R Suhre, K Quinn, PK Bates, T Andreae, MO Noone, KJ Glantz, P Bandy, B Rudolph, J O'Dowd, C AF Johnson, DW Osborne, S Wood, R Suhre, K Quinn, PK Bates, T Andreae, MO Noone, KJ Glantz, P Bandy, B Rudolph, J O'Dowd, C TI Observations of the evolution of the aerosol, cloud and boundary-layer characteristics during the 1st ACE-2 Lagrangian experiment SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID STRATOCUMULUS TRANSITION EXPERIMENT; SEA-SALT; ATMOSPHERIC AEROSOLS; PARTICLE-PRODUCTION; MARINE; ATLANTIC; ASTEX AB During the Ist Lagrangian experiment of the North Atlantic Regional Aerosol Characterisation Experiment (ACE-2), a parcel of air was tagged by releasing a smart, constant level balloon into it from the Research Vessel Vodyanitskiy. The Meteorological Research Flight's C-130 aircraft then followed this parcel over a period of 30 h characterising the marine boundary layer (MBL), the cloud and the physical and chemical aerosol evolution. The air mass had originated over the northern North Atlantic and thus was clean and had low aerosol concentrations. At the beginning of the experiment the MBL was over 1500 m deep and made up of a surface mixed layer (SML) underlying a layer containing cloud beneath a subsidence inversion. Subsidence in the free troposphere caused the depth of the MBL to almost halve during the experiment and, after 26 h, the MBL became well mixed throughout its whole depth. Salt particle mass in the MBL increased as the surface wind speed increased from 8 m s(-1) to 16 m s(-1) and the accumulation mode (0.1 mu m to 3.0 mu m) aerosol concentrations quadrupled from 50 cm(-3) to 200 cm(-3). However, at the same time the total condensation nuclei (> 3 nm) decreased from over 1000 cm(-3) to 750 cm(-3). The changes in the accumulation mode aerosol concentrations had a significant effect on the observed cloud microphysics. Observational evidence suggests that the important processes in controlling the Aitken mode concentration which, dominated the total CN concentration, included, scavenging of interstitial aerosol by cloud droplets, enhanced coagulation of Aitken mode aerosol and accumulation mode aerosol due to the increased sea salt aerosol surface area, and dilution of the MBL by free tropospheric air. C1 DERA, Meteorol Res Flight, Farnborough GU14 0LX, Hants, England. Univ Toulouse, Toulouse, France. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. MPIC, Mainz, Germany. Univ Stockholm, MISU, S-10691 Stockholm, Sweden. Univ E Anglia, Norwich NR4 7TJ, Norfolk, England. York Univ, N York, ON M3J 1P3, Canada. Univ Sunderland, CMAS, Sunderland SR2 7EE, Durham, England. RP Johnson, DW (reprint author), DERA, Meteorol Res Flight, Bldg Y46, Farnborough GU14 0LX, Hants, England. RI Wood, Robert/A-2989-2008; O'Dowd , Colin/K-8904-2012; Bates, Timothy/L-6080-2016; Andreae, Meinrat/B-1068-2008; Quinn, Patricia/R-1493-2016; OI Wood, Robert/0000-0002-1401-3828; O'Dowd , Colin/0000-0002-3068-2212; Andreae, Meinrat/0000-0003-1968-7925; Quinn, Patricia/0000-0003-0337-4895; Suhre, Karsten/0000-0001-9638-3912 NR 39 TC 28 Z9 29 U1 1 U2 8 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 348 EP 374 DI 10.1034/j.1600-0889.2000.00087.x PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900015 ER PT J AU Osborne, SR Johnson, DW Wood, R Bandy, BJ Andreae, MO O'Dowd, CD Glantz, P Noone, KJ Gerbig, C Rudolph, J Bates, TS Quinn, P AF Osborne, SR Johnson, DW Wood, R Bandy, BJ Andreae, MO O'Dowd, CD Glantz, P Noone, KJ Gerbig, C Rudolph, J Bates, TS Quinn, P TI Evolution of the aerosol, cloud and boundary-layer dynamic and thermodynamic characteristics during the 2nd Lagrangian experiment of ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID CONDENSATION NUCLEI; SIZE DISTRIBUTION; EFFECTIVE-RADIUS; SULFUR-DIOXIDE; SEA-SALT; STRATOCUMULUS; ATMOSPHERE; SCATTERING; GROWTH; LIGHT AB We present observations From the 2nd Aerosol Characterisation Experiment where over a 29-h period between 16-18 July 1997 a tagged column of air was followed by a fully instrumented aircraft, The Lagrangian framework this offered made it possible to measure the evolution of the aerosol size distribution, the cloud structure and microphysics, and the dynamic and thermo-dynamic structure of the marine boundary layer within a polluted airmass advecting off northwest Europe over the sub-tropical North Atlantic Ocean. The salient observations are presented and analysed. processes responsible for the evolution are suggested, but quantification of their respective rates must be taken up by Future modelling studies. Stratocumulus capped the boundary layer throughout the period that produced negligible washout of aerosol. This implies that the conversion of a continental to a maritime airmass within the cloud-capped sub-tropical marine boundary layer is not controlled by the drizzle process but by entrainment from the free troposphere. We find evidence of processing of aerosol particles by stratocumulus cloud, in particular by aqueous-phase reactions. The processing of the aerosol, realised by modification of the aerosol size distribution in the particle diameter range 0.1-0.5 pm, was complicated by rapid changes in boundary layer height and structure, and also by entrainment of both polluted and relatively clean aerosol from the free troposphere. The cloud microphysics was affected by these changes in the boundary layer aerosol through changes in the cloud condensation nuclei activation spectra. The cloud microphysics was also strongly affected by changes in the dynamics of the boundary layer which included variations (e.g., diurnal) in cloud thickness and an increase in vertical wind speed. Thermodynamic changes within the boundary layer included decoupling due to an increasing sea-surface temperature and a change in the subsidence rate in the free troposphere superimposed on diurnal decoupling. Hypotheses have been devised so that future modellers can Focus their efforts to either validate or invalidate potentially important processes. C1 DERA, Meteorol Res Flight, Farnborough GU14 0LX, Hants, England. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. Max Planck Inst Chem, Biogeochem Dept, D-55128 Mainz, Germany. Univ Sunderland, Ctr Marine & Atmospher Sci, Sunderland SR2 7EE, Durham, England. Univ Stockholm, Dept Meteorol, S-10691 Stockholm, Sweden. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. York Univ, Ctr Atmospher Chem, Toronto, ON M3J 2R7, Canada. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Osborne, SR (reprint author), DERA, Meteorol Res Flight, Y46 Bldg, Farnborough GU14 0LX, Hants, England. EM sosborne@meto.gov.uk RI Wood, Robert/A-2989-2008; Gerbig, Christoph/L-3532-2013; O'Dowd , Colin/K-8904-2012; Bates, Timothy/L-6080-2016; Andreae, Meinrat/B-1068-2008; Quinn, Patricia/R-1493-2016 OI Wood, Robert/0000-0002-1401-3828; Gerbig, Christoph/0000-0002-1112-8603; O'Dowd , Colin/0000-0002-3068-2212; Andreae, Meinrat/0000-0003-1968-7925; Quinn, Patricia/0000-0003-0337-4895 NR 36 TC 28 Z9 28 U1 0 U2 6 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 375 EP 400 DI 10.1034/j.1600-0889.2000.00051.x PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900016 ER PT J AU Wood, R Johnson, D Osborne, S Andreae, MO Bandy, B Bates, TS O'Dowd, C Glantz, P Noone, K Quinn, PK Rudolph, J Suhre, K AF Wood, R Johnson, D Osborne, S Andreae, MO Bandy, B Bates, TS O'Dowd, C Glantz, P Noone, K Quinn, PK Rudolph, J Suhre, K TI Boundary layer and aerosol evolution during the 3rd Lagrangian experiment of ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID SPECTROMETER PROBE; ENTRAINMENT; PARAMETERIZATION; INSTABILITY; PARTICLES; DYNAMICS; SURFACE; NUMBER; MODEL AB Aircraft measurements are presented of the Lagrangian evolution of a marine boundary layer over a 30-h period during the ACE-2 field campaign. At the start of the observational period, a 500-m deep polluted marine internal boundary layer (MIBL) was overlain by the remnants of a polluted continental boundary layer extending to around 2 km below a clean, dry free troposphere. The MIBL grew rapidly to a thickness of 900-1000 m in response to increasing sea surface temperatures. No significant aerosol spectral evolution was observed in the boundary layer. Low concentrations of SO2 were observed in the MIBL suggesting that the air mass contained relatively aged aerosol. Aerosol spectra show a broad mode with a modal diameter of around 0.1 mu m. The polluted layer between the MIBL and the unpolluted free troposphere was only weakly and intermittently turbulent which prevented significant entrainment of clean air into the polluted layer from aloft. The polluted layer depth was thus controlled mainly by subsidence which as a result becomes shallower, decreasing from over 2000 m to around 1200 m during the observational period. The aerosol characteristics of the polluted layer were similar to those in the MIBL and so although the MIBL entrained considerable amounts of air from above the MIBL the aerosol characteristics underwent no significant change. This has important implications for the rate at which a polluted continental air mass is converted to a clean marine one. The dataset should prove useful in the validation of the modelling of continental pollution outbreaks. C1 DERA, Meteorol Res Flight, Farnborough GU14 0LX, Hants, England. Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. Max Planck Inst, Biogeochem Dept, Mainz, Germany. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Sunderland, Ctr Marine & Atmospher Sci, Sunderland SR2 7EE, Durham, England. Univ Stockholm, Dept Meteorol, S-10691 Stockholm, Sweden. Lab Aerol, Toulouse, France. York Univ, Ctr Atmospher Chem, N York, ON M3J 1P3, Canada. RP Wood, R (reprint author), DERA, Meteorol Res Flight, Bldg Y46, Farnborough GU14 0LX, Hants, England. RI Wood, Robert/A-2989-2008; O'Dowd , Colin/K-8904-2012; Bates, Timothy/L-6080-2016; Andreae, Meinrat/B-1068-2008; Quinn, Patricia/R-1493-2016; OI Wood, Robert/0000-0002-1401-3828; O'Dowd , Colin/0000-0002-3068-2212; Andreae, Meinrat/0000-0003-1968-7925; Quinn, Patricia/0000-0003-0337-4895; Suhre, Karsten/0000-0001-9638-3912 NR 40 TC 33 Z9 33 U1 1 U2 7 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 401 EP 422 DI 10.1034/j.1600-0889.2000.00058.x PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900017 ER PT J AU Van Dingenen, R Virkkula, AO Raes, F Bates, TS Wiedensohler, A AF Van Dingenen, R Virkkula, AO Raes, F Bates, TS Wiedensohler, A TI A simple non-linear analytical relationship between aerosol accumulation number and sub-micron volume, explaining their observed ratio in the clean and polluted marine boundary layer SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID SIZE DISTRIBUTION; SEA-SALT; NORTHEAST ATLANTIC; CLOUDS AB We propose an analytical expression for the relation between aerosol accumulation number and sub-micron volume over the marine boundary layer (MBL), based on a simple balance equation. By providing appropriate source and sink terms which account for entrainment, coagulation, in-cloud scavenging and condensational growth, the model is able to reproduce the observed ratio between MBL particles larger than 80 nm diameter (as a proxy for accumulation mode number) and submicron aerosol volume, from freshly polluted to background conditions. Entrainment and coagulation are essential in predicting the observed ratio. Budget and lifetime calculations show that, due to relatively low source rates of oceanic non-sea-salt-sulfate and sea-salt, the anthropogenic signature in aerosol volume remains significant even after 8 days of MBL transport. C1 Commiss European Communities, Joint Res Ctr, Inst Environm, I-21020 Ispra, VA, Italy. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Inst Tropospher Res, D-04303 Leipzig, Germany. RP Van Dingenen, R (reprint author), Commiss European Communities, Joint Res Ctr, Inst Environm, TP 460, I-21020 Ispra, VA, Italy. RI Virkkula, Aki/B-8575-2014; Bates, Timothy/L-6080-2016 NR 25 TC 21 Z9 21 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 439 EP 451 DI 10.1034/j.1600-0889.2000.00091.x PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900019 ER PT J AU Durkee, PA Nielsen, KE Smith, PJ Russell, PB Schmid, B Livingston, JM Holben, BN Tomasi, C Vitale, V Collins, D Flagan, RC Seinfeld, JH Noone, KJ Ostrom, E Gasso, S Hegg, D Russell, LM Bates, TS Quinn, PK AF Durkee, PA Nielsen, KE Smith, PJ Russell, PB Schmid, B Livingston, JM Holben, BN Tomasi, C Vitale, V Collins, D Flagan, RC Seinfeld, JH Noone, KJ Ostrom, E Gasso, S Hegg, D Russell, LM Bates, TS Quinn, PK TI Regional aerosol optical depth characteristics from satellite observations: ACE-1, TARFOX and ACE-2 results SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID RADIANCES AB Analysis of the aerosol properties during 3 recent international field campaigns (ACE-1, TARFOX and ACE-2) are described using satellite retrievals from NOAA AVHRR data. Validation of the satellite retrieval procedure is performed with airborne, shipboard, and land-based sunphotometry during ACE-2. The intercomparison between satellite and surface optical depths has a correlation coefficient of 0.93 for 630 nm wavelength and 0.92 for 860 nm wave length. The standard error of estimate is 0.025 for 630 nm wavelength and 0.023 for 860 nm wavelength. Regional aerosol properties are examined in composite analysis of aerosol optical properties from the ACE-1, TARFOX and ACE-2 regions. ACE-1 and ACE-2 regions have strong modes in the distribution of optical depth around 0.1, but the ACE-2 tails toward higher values yielding an average of 0.16 consistent with pollution and dust aerosol intrusions. The TARFOX region has a noticeable mode of 0.2, but has significant spread of aerosol optical depth values consistent with the varied continental aerosol constituents off the eastern North American Coast. C1 USN, Postgrad Sch, Monterey, CA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SRI Int, Menlo Pk, CA 94025 USA. Bay Area Environm Res Inst, San Francisco, CA 94122 USA. CALTECH, Pasadena, CA 91125 USA. Stockholm Univ, S-10691 Stockholm, Sweden. Univ Washington, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Princeton Univ, Princeton, NJ 08544 USA. FISBAT, Bologna, Italy. RP Durkee, PA (reprint author), 589 Dyer Rd,Room 254, Monterey, CA 93943 USA. EM Durkee@nps.navy.mil RI Collins, Don/F-9617-2012; Gasso, Santiago/H-9571-2014; Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Gasso, Santiago/0000-0002-6872-0018; Quinn, Patricia/0000-0003-0337-4895 NR 34 TC 19 Z9 19 U1 0 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 484 EP 497 DI 10.1034/j.1600-0889.2000.00040.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900022 ER PT J AU Livingston, JM Kapustin, VN Schmid, B Russell, PB Quinn, PK Bates, TS Durkee, PA Smith, PJ Freudenthaler, V Wiegner, M Covert, DS Gasso, S Hegg, D Collins, DR Flagan, RC Seinfeld, JH Vitale, V Tomasi, C AF Livingston, JM Kapustin, VN Schmid, B Russell, PB Quinn, PK Bates, TS Durkee, PA Smith, PJ Freudenthaler, V Wiegner, M Covert, DS Gasso, S Hegg, D Collins, DR Flagan, RC Seinfeld, JH Vitale, V Tomasi, C TI Shipboard sunphotometer measurements of aerosol optical depth spectra and columnar water vapor during ACE-2, and comparison with selected land, ship, aircraft, and satellite measurements SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID MARINE BOUNDARY-LAYER; ATLANTIC; OCEANS AB Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements acquired with NASA Ames Research Center's 6-channel Airborne Tracking Sunphotometer (AATS-6) operated aboard the R/V Professor Vodyanitskiy during the 2nd Aerosol Characterization Experiment (ACE-2) are discussed. Data are compared with various in situ and remote measurements for selected cases. The focus is on 10 July, when the Pelican airplane flew within 70 km of the ship near the time of a NOAA-14/AVHRR satellite overpass and AOD measurements with the 14-channel Ames Airborne Tracking Sunphotometer (AATS-14) above the marine boundary layer (MBL) permitted calculation of AOD within the MBL from the AATS-6 measurements. A detailed column closure test is performed for MBL AOD on 10 July by comparing the AATS-6 MBL AODs with corresponding values calculated by combining shipboard particle size distribution measurements with models of hygroscopic growth and radiosonde humidity profiles (plus assumptions on the vertical profile of the dry particle size distribution and composition). Large differences (30 80% in the mid-visible) between measured and reconstructed AODs are obtained, in large part because of the high sensitivity of the closure methodology to hygroscopic growth models, which vary considerably and have not been validated over the necessary range of particle size/composition distributions. The wavelength dependence of AATS-6 AODs is compared with the corresponding dependence of aerosol extinction calculated from shipboard measurements of aerosol size distribution and of total scattering measured by a shipboard integrating nephelometer for several days. Results are highly variable, illustrating further the great difficulty of deriving column values from point measurements. AATS-6 CWV values are shown to agree well with corresponding values derived from radiosonde measurements during 8 soundings on 7 days and also with values calculated from measurements taken on 10 July with the AATS-14 and the University of Washington Passive Humidigraph aboard the Pelican. C1 SRI Int, Menlo Pk, CA 94025 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. Bay Area Environm Res Inst, San Francisco, CA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. USN, Postgrad Sch, Monterey, CA USA. Univ Munich, Munich, Germany. Univ Washington, Seattle, WA 98195 USA. CALTECH, Pasadena, CA 91125 USA. CNR, Ist Fisbat, I-40126 Bologna, Italy. RP Livingston, JM (reprint author), SRI Int, 333 Ravenswood Ave, Menlo Pk, CA 94025 USA. EM jlivingston@mail.arc.nasa.gov RI Collins, Don/F-9617-2012; Wiegner, Matthias/F-8484-2011; Gasso, Santiago/H-9571-2014; Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Gasso, Santiago/0000-0002-6872-0018; Quinn, Patricia/0000-0003-0337-4895 NR 36 TC 17 Z9 17 U1 0 U2 3 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 EI 1600-0889 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 594 EP 619 DI 10.1034/j.1600-0889.2000.00045.x PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900027 ER PT J AU Flamant, C Pelon, J Chazette, P Trouillet, V Quinn, PK Frouin, R Bruneau, D Leon, JF Bates, TS Johnson, J Livingston, J AF Flamant, C Pelon, J Chazette, P Trouillet, V Quinn, PK Frouin, R Bruneau, D Leon, JF Bates, TS Johnson, J Livingston, J TI Airborne lidar measurements of aerosol spatial distribution and optical properties over the Atlantic Ocean during a European pollution outbreak of ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID METEOSAT ISCCP-B2 DATA; SAHARAN DUST LOAD; SIZE DISTRIBUTIONS; BOUNDARY-LAYER; NEPHELOMETER; SENSITIVITY AB Airborne lidar measurements of the aerosol spatial distribution and optical properties associated with an European pollution outbreak which occured during the Second Aerosol Characterization Experiment (ACE-2) are presented. Size distribution spectra measured over the ocean near Sagres (Portugal), on-board the Research Vessel Vodyanitsky and on-board the Avion de Recherche Atmospherique et Teledetection (ARAT) have been used to parameterize the aerosol vertical distribution. This parameterization, which is essential to the analysis of airborne lidar measurements, has been validated via closure experiments on extinction coefficient profiles and aerosol optical depth (AOD). During the studied event, AOD's retrieved from lidar measurements at 0.73 mu m range between 0.055 and 0.10. The parameterized aerosol vertical distribution has been used to shift AOD retrievals from 0.73 to 0.55 mu m to enable comparison with other remote sensing instruments. At the latter wavelength, AOD's retrieved from lidar measurements range between 0.08 and 0.14. An agreement better than 20% is obtained between AOD's derived from lidar and sunphotometer measurements made at the same time and place over the ocean near the coast. However, large differences are observed with the AOD estimated from Meteosat imagery in the same area. These differences are thought to be caused by large uncertainties associated with the Meteosat sensitivity for small AOD's or by the presence of thin scattered clouds. Lidar-derived particulate extinction profiles and scattering coefficient profiles measured by a nephelometer mounted on the ARAT, in a different part of the plume, were found in good agreement, which could be an indication that absorption by pollution aerosols is small and/or that soot is present in small amounts in the European pollution plume. Lidar measurements have also been used to differentiate the contribution of different aerosol layers to the total AOD. It is shown that the AOD in the marine atmospheric boundary layer (MABL) can contribute as much as 70% of the total AOD in some regions. At 0.73 mu m, the AOD in the continental plume was observed to diminish with the distance to the coastline from 0.04 to 0.03. C1 Univ Paris 06, CNRS, Serv Aeron, UVSQ, F-75252 Paris 05, France. CEA, CNRS, Lab Sci Climat & Environm, Gif Sur Yvette, France. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Scripps Inst Oceanog, La Jolla, CA USA. SRI Int, Menlo Park, CA 94025 USA. RP Flamant, C (reprint author), Univ Paris 06, CNRS, Serv Aeron, UVSQ, Tour 15,Boite 102,4 Pl Jussieu, F-75252 Paris 05, France. RI Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 38 TC 34 Z9 35 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 662 EP 677 DI 10.1034/j.1600-0889.2000.00083.x PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900031 ER PT J AU Carrico, CM Rood, MJ Ogren, JA Neususs, C Wiedensohler, A Heintzenberg, J AF Carrico, CM Rood, MJ Ogren, JA Neususs, C Wiedensohler, A Heintzenberg, J TI Aerosol optical properties at Sagres, Portugal during ACE-2 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID RELATIVE-HUMIDITY; LIGHT-SCATTERING; ANTHROPOGENIC AEROSOLS; TROPOSPHERIC AEROSOLS; ATMOSPHERIC SULFUR; AMMONIUM-NITRATE; UNITED-STATES; CLIMATE; NEPHELOMETER; SULFATE AB Aerosol light scattering and absorption properties relevant to climate change were measured as part of the Aerosol Characterization Experiment 2 (ACE-2, 15 June to 25 July 1997) at Sagres, Portugal, a site receiving anthropogenically perturbed air masses from Europe. A controlled relative humidity (RH) nephelometry system measured the dependence of the total light scattering and backscattering coefficients by particles (sigma(sp) and sigma(bsp), respectively) upon increasing and decreasing controlled RH, maximum particle diameter (D(p)) size cut, and wavelength of scattered light (lambda). An aethalometer was used to measure black carbon concentrations ([BC]) to yield estimates of light absorption by particles (sigma(ap)) and single scattering albedo (omega). Parameters derived from the measurements include the dependence of sigma(sp) and sigma(bsp) on RH (f(RH)), the hemispheric backscatter fraction (b), and the Angstrom exponent ((a) over circle), all as functions of lambda and particle D(p) size cut. During polluted periods, for D(p) less than or equal to 10 mu m, and at lambda = 550 nm, means and standard deviations of aerosol parameters included sigma(sp) = 75.1 +/- 30.5 Mm(-1) at controlled RH = 27%, f(RH = 82%) = 1.46 +/- 0.10 and 1.22 +/- 0.06 for sigma(sp) and sigma(bsp), respectively, and b = 0.113 +/- 0.017 and 0.094 +/- 0.015 at controlled RH = 27% and 82%, respectively. Transition from "clean" to polluted periods was characterized by a mean increase in sigma(sp) and sigma(bsp) by a factor of 4 to 7, increased wavelength dependence evident from an increase in (a)over dot from 0.57 to 1.48, shift from 0.32 to 0.56 of the fraction of sigma(sp) from sub-micrometer D(p) particles, and suppression of f(RH) by 14 to 20%. Onset of polluted periods and aerosol hygroscopic growth each resulted in similar to 1% increases in omega, and an estimated range for omega at Sagres during ACE-2 was 0.91 < omega < 0.97 considering uncertainty of +/- 0.02 aerosol hygroscopic growth, and air mass influences. Evidence for the influence of hysteresis in f(RH) was greatest at RH = 65% with mean increases of 20% during "clean" periods and 10% during polluted periods. These measurements contribute to characterizing ground-level aerosol optical properties for a site that receives "clean" and anthropogenically perturbed aerosol. C1 Univ Illinois, Dept Civil & Environm Engn, Newmark Civil Engn Lab 3230, Urbana, IL 61801 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Inst Tropospher Res, D-04303 Leipzig, Germany. RP Rood, MJ (reprint author), Univ Illinois, Dept Civil & Environm Engn, Newmark Civil Engn Lab 3230, MC-250,205 N Mathews Ave, Urbana, IL 61801 USA. EM m-rood@uiuc.edu RI Ogren, John/M-8255-2015 OI Ogren, John/0000-0002-7895-9583 NR 68 TC 80 Z9 86 U1 0 U2 9 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2000 VL 52 IS 2 BP 694 EP 715 DI 10.1034/j.1600-0889.2000.00049.x PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 316BR UT WOS:000087147900033 ER PT J AU Gates, RS Hsu, SM AF Gates, RS Hsu, SM TI Silicon nitride boundary lubrication: Effect of sulfonate, phenate and salicylate compounds SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 54th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 23-27, 1999 CL LAS VEGAS, NEVADA SP Soc Tribologists & Lubricat Engineers DE detergents; friction; lubrication; silicon nitride; tribochemistry; wear AB The boundary lubrication characteristics of sulfonates phenates, and salicylates in a silicon nitride on silicon nitride contact were investigated. The additives were blended at one percent by weight solution in a purified paraffinic base oil and tested on a ball-on-three flat geometry in the Four-Ball Tester. These compounds all exhibited effective lubricating properties for silicon nitride, including both loew base and high base types. Lower friction and wear were observed as compared to the base paraffin base-oil case. Load capacity tests indicated that these compounds had extended load ranges for silicon nitride. Boundary films were observed in the wear scar suggesting the occurrence of tribo-chemical reactions. Surface analysis of the worn surface revealed the presence of the metal salt portion of the compound but without the calcium carbonate which was used for overbasing. This suggests that these compounds probably oxidize and then adsorb onto the surface to form lubricating films containing the metal salts. It is hypothesized that upon decomposition, the metal portion of the detergent molecule reacts with the silicon oxide surface layer of the Si3N4, producing a complex silicate amorphous "glass" structure which protects the Si3N4 from fracture and damage. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Gates, RS (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 12 TC 3 Z9 3 U1 0 U2 2 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD APR PY 2000 VL 43 IS 2 BP 269 EP 274 DI 10.1080/10402000008982339 PG 6 WC Engineering, Mechanical SC Engineering GA 307YL UT WOS:000086681700015 ER PT J AU Ravikiran, A AF Ravikiran, A TI Wear mechanism based on wear anisotropy SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 54th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 23-27, 1999 CL LAS VEGAS, NEVADA SP Soc Tribologists & Lubricat Engineers DE ceramics; wear and failure; wear mechanism; wear anisotropy ID ALUMINA; TRANSITION AB Self-mated dry sliding wear experiments were conducted on alumina using a pin-on-disc configuration. Worn alumina surface showed pits and projections in the size and shape of the grains. This paper shows that formation of these pits and projections are due to the wear anisotropy observed in single crystal alumina. Formation of different morphologies within the pits is also shown to be due to the wear anisotropy. Using an independent wear experiment, a model has been proposed that shows that during sliding unger load, the pits and projections experience preferential elastic deformation such that their surfaces become co-planar. Based on this model and the observed surface morphological evidence, a new wear mechanism has been proposed. According to this mechanism, during sliding under load, the boundary of such an elastically compressed grain at the grain pits becomes weak due to additional shear; tensile, compressive and thermal stresses. Whenever this combined stress exceeds the grain boundary strength, failure of the boundary occurs resulting in wear transition (severe fracture). It is speculated that this mechanism can be extended to any composite material whose constituent materials have different wear rates and also to single-phase materials with grains having wear anisotropy. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Ravikiran, A (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 15 TC 7 Z9 7 U1 0 U2 1 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD APR PY 2000 VL 43 IS 2 BP 287 EP 292 DI 10.1080/10402000008982342 PG 6 WC Engineering, Mechanical SC Engineering GA 307YL UT WOS:000086681700018 ER PT J AU Masad, E Muhunthan, B Martys, N AF Masad, E Muhunthan, B Martys, N TI Simulation of fluid flow and permeability in cohesionless soils SO WATER RESOURCES RESEARCH LA English DT Article AB This paper reports on a new laboratory methodology for the determination of the structure of pores, a method for the analysis of the data to obtain the statistics of the pore structure distribution, simulation of porous media with statistics consistent with those in the specimens, numerical simulation of fluid flow in images of porous media, and the determination of permeabilities from the numerical experiments and comparison with the results of laboratory experiments. The computed flow fields show that flow in porous media is restricted to preferential paths depending on the size and connectivity of pores. Whole areas of the pore structure are relatively isolated from the flow because of bottlenecks. The distribution of the isolated regions depends on the angularity of the grains and the porosity of the medium. The more angular the grains are the greater is the possibility for the presence of isolated regions. For grains with the same angularity a decrease in the porosity leads to concentration of flow along preferential flow paths. The permeability tensor coefficients are derived from the flow fields of the two-dimensional images as well as the three-dimensional computer-simulated images of soil microstructure. The numerical values of permeability and permeability anisotropy ratio compare well with laboratory experimental data. C1 Washington State Univ, Dept Civil & Environm Engn, Pullman, WA 99164 USA. Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Masad, E (reprint author), Washington State Univ, Dept Civil & Environm Engn, POB 642910, Pullman, WA 99164 USA. NR 28 TC 22 Z9 22 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 APR PY 2000 VL 36 IS 4 BP 851 EP 864 DI 10.1029/1999WR900348 PG 14 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 297NY UT WOS:000086090000003 ER PT J AU Zhou, CN Hsu, NN Popovics, JS Achenbach, JD AF Zhou, CN Hsu, NN Popovics, JS Achenbach, JD TI Response of two layers overlaying a half-space to a suddenly applied point force SO WAVE MOTION LA English DT Article AB Expressions for the elastodynamic displacements, generated by a normal point force acting on the top layer of two isotropic layers overlaying an isotropic half-space, are derived. Generalized ray theory is used to develop the displacement expressions. In particular, a combinatorial technique for counting the number of wave rays simultaneously arriving at a specific point on the free surface of the top layer is developed. Reflection and transmission coefficients are derived, the different travel paths are analyzed, the products of the reflection and transmission coefficients are generated, and the arrival times of signals traveling along various rays, including head waves, are obtained. A computer program has been developed for efficient numerical implementation of the formulation. Numerical results are shown. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Drexel Univ, Dept Civil & Architectural Engn, Philadelphia, PA 19104 USA. Northwestern Univ, Ctr Qual Engn & Failure Prevent, Evanston, IL 60208 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Popovics, JS (reprint author), Drexel Univ, Dept Civil & Architectural Engn, Philadelphia, PA 19104 USA. RI Achenbach, Jan/B-6746-2009 NR 10 TC 6 Z9 6 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-2125 J9 WAVE MOTION JI Wave Motion PD APR PY 2000 VL 31 IS 3 BP 255 EP 272 DI 10.1016/S0165-2125(99)00020-7 PG 18 WC Acoustics; Mechanics; Physics, Multidisciplinary SC Acoustics; Mechanics; Physics GA 292MQ UT WOS:000085799100005 ER PT J AU Schultz, DM Doswell, CA AF Schultz, DM Doswell, CA TI Analyzing and forecasting Rocky Mountain lee cyclogenesis often associated with strong winds SO WEATHER AND FORECASTING LA English DT Article ID NESTED-GRID MODEL; SURFACE CYCLONE FORECASTS; GLOBAL SPECTRAL MODEL; UNITED-STATES; OBJECTIVE ANALYSIS; MESOSCALE MODELS; NORTH-AMERICA; COLD-FRONT; CLIMATOLOGY; WEATHER AB Since numerical forecast models often err in predicting the timing and location of lee cyclogenesis, a physically based method to diagnose such errors is sought. A case of Rocky Mountain lee cyclogenesis associated with strong winds is examined to explore the transformation from a stationary lee trough to a mobile midlatitude cyclone thereafter, departure). Up to 12 h before departure, a pronounced surface pressure trough travels eastward across western North America at an average speed of 22 m s(-1). Several methods are employed to examine the structure and evolution of the pressure held: total sea level pressure, time series at individual stations, isallobars, and bandpass filtering. Bandpass filtering of the observed sea level pressure data is useful for clarifying the movement of the mobile trough through the complex terrain. Quasigeostrophic height-tendency diagnostics show that the mobile pressure trough is related to the traveling mid- to upper-tropospheric vorticity maximum that is responsible for departure. At many stations, surface temperature changes associated with this pressure trough are not consistent with those commonly associated with surface frontal passages. To test the hypothesis that mobile pressure troughs are associated with departure, a five-winter climatology of 111 southern Alberta lee cyclones is constructed. Sixty-two percent of these events feature an upstream pressure minimum 3-9 h prior to departure, in a manner resembling the case study. Seventy-six percent of these 111 events are associated with reports listed in Storm Data. indicating the potential severity of these storms. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Schultz, DM (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. RI Doswell III, Charles/E-7662-2010; Schultz, David M./A-3091-2010 OI Schultz, David M./0000-0003-1558-6975 NR 88 TC 22 Z9 22 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD APR PY 2000 VL 15 IS 2 BP 152 EP 173 DI 10.1175/1520-0434(2000)015<0152:AAFRML>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302HG UT WOS:000086359200002 ER PT J AU Bogner, PB Barnes, GM Franklin, JL AF Bogner, PB Barnes, GM Franklin, JL TI Conditional instability and shear for six hurricanes over the Atlantic Ocean SO WEATHER AND FORECASTING LA English DT Article ID CONVECTIVE-SCALE CHARACTERISTICS; BOUNDARY-LAYER STRUCTURE; SURFACE WIND FIELDS; MATURE HURRICANES; CORE STRUCTURE; SQUALL-LINE; MESOSCALE; STORMS; RAINBAND; DYNAMICS AB One hundred and thirty Omega dropwindsondes deployed within 500-km radius of the eye of six North Atlantic hurricanes are used to determine the magnitudes and trends in convective available potential energy, and 10-1500-m and 0-6-km shear of the horizontal wind as a function of radius, quadrant, and hurricane intensity. The moist convective instability found at large radii (400-500 km) decreases to near neutral stability by 75 km from the eyewall. Vertical shears increase as radius decreases, but maximum shear values are only one-half of those found over land. Scatter for birth the conditional instability and the shear is influenced chiefly by hurricane intensity, but proximity to reflectivity features does modulate the pattern. The ratio of the conditional instability to the shear (bulk Richardson number) indicates that supercell formation is favored within 250 km of the circulation center, but helicity values are below the threshold to support strong waterspouts. The difference between these oceanic observations and those made over land by other researchers is evidence for significant modification of the vertical profile of the horizontal wind in a hurricane at landfall. C1 Univ Hawaii, Dept Meteorol, Honolulu, HI 96822 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Barnes, GM (reprint author), Univ Hawaii, Dept Meteorol, 2525 Correa Rd, Honolulu, HI 96822 USA. NR 54 TC 50 Z9 52 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD APR PY 2000 VL 15 IS 2 BP 192 EP 207 DI 10.1175/1520-0434(2000)015<0192:CIASFS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302HG UT WOS:000086359200004 ER PT J AU Brown, RA Wood, VT Sirmans, D AF Brown, RA Wood, VT Sirmans, D TI Improved WSR-88D scanning strategies for convective storms SO WEATHER AND FORECASTING LA English DT Article ID RADAR AB The Weather Surveillance Radar-1988 Doppler (WSR-88D) is an important operational and research tool for detecting and monitoring convective storms. Two scanning strategies, or volume coverage patterns, VCP 11 and 21, are used in storm situations. Users find that these original VCPs do not always provide the vertical or temporal resolution that is desired. To help solve these resolution problems, a procedure is proposed far developing optimized and flexible VCPs. A VCP is optimized when the maximum height uncertainty (expressed in percent of true height) is essentially the same at all ranges and For all heights of storm features. A VCP becomes flexible when the volume scan terminates and recycles after it tilts above all radar return or reaches a specified elevation angle. Two sample VCPs, which are optimized and flexible, are presented, and simulated radar data show that they perform better than the current VCPs. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Syst Technol Associates Inc, Norman, OK USA. RP Brown, RA (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 16 TC 16 Z9 22 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD APR PY 2000 VL 15 IS 2 BP 208 EP 220 DI 10.1175/1520-0434(2000)015<0208:IWSSFC>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 302HG UT WOS:000086359200005 ER PT J AU Lavrentyev, PJ Gardner, WS Yang, LY AF Lavrentyev, PJ Gardner, WS Yang, LY TI Effects of the zebra mussel on nitrogen dynamics and the microbial community at the sediment-water interface SO AQUATIC MICROBIAL ECOLOGY LA English DT Article DE nitrogen; microbial food web; sediment-water interface; bivalve mussels ID DREISSENA-POLYMORPHA; SAGINAW BAY; LAKE HURON; FRESH-WATER; BACTERIA; AMMONIUM; DENITRIFICATION; NITRIFICATION; ESTUARINE; BACTERIOPLANKTON AB A flow-through experiment was conducted on intact cores of sediments from Saginaw Bay, Lake Huron, to examine how trophic interactions between filter-feeding bivalve mussels and microbial populations could affect nitrogen dynamics at the sediment-water interface. The zebra mussels used in this experiment removed a large proportion of protozoa and phytoplankton from the overlying water, particularly heterotrophic nanoplankton (up to 82%), while bacterial populations showed less change. A 3-fold decrease in the protozoan to bacterial carbon ratio corresponded to a 2.5-fold increase in relative ammonium removal rates as estimated from the dark loss of N-15-ammonium. Excretion by the bivalves also increased net ammonium flux to the water, thus elevating the total calculated areal ammonium removal rates to about B-fold over rates observed in the control treatment. These data suggest that filter-feeding bivalves may significantly affect nitrogen transformation rates near the sediment-water interface by excreting ammonium and altering the microbial food web structure at the sediment-water interface. C1 Univ Michigan, Cooperat Inst Limnol & Ecosyst Res, Ann Arbor, MI 48109 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. Chinese Acad Sci, Nanjing Inst Geog & Limnol, Nanjing 21008, Jiangsu, Peoples R China. RP Lavrentyev, PJ (reprint author), Univ Akron, Dept Biol, Akron, OH 44325 USA. EM peterl@uakron.edu RI Ross, Donald/F-7607-2012 OI Ross, Donald/0000-0002-8659-3833 NR 49 TC 61 Z9 64 U1 2 U2 32 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0948-3055 EI 1616-1564 J9 AQUAT MICROB ECOL JI Aquat. Microb. Ecol. PD MAR 31 PY 2000 VL 21 IS 2 BP 187 EP 194 DI 10.3354/ame021187 PG 8 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 309KE UT WOS:000086766400009 ER PT J AU Markelz, AG Roitberg, A Heilweil, EJ AF Markelz, AG Roitberg, A Heilweil, EJ TI Pulsed terahertz spectroscopy of DNA, bovine serum albumin and collagen between 0.1 and 2.0 THz SO CHEMICAL PHYSICS LETTERS LA English DT Article ID B-DNA; MODES; PROTEINS; FILMS AB We report the first use of pulsed terahertz spectroscopy to examine low-frequency collective vibrational modes of biomolecules. Broadband absorption increasing with frequency was observed for lyophilized powder samples of calf thymus DNA, bovine serum albumin and collagen in the 0.06-2.00 THz (2-67 cm(-1)) frequency range, suggesting that a large number of the low-frequency collective modes for these systems are IR active. Transmission measurements at room temperature showed increasing FIR absorption with hydration and denaturing. (C) 2000 published by Elsevier Science B.V. All rights reserved. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. Lucent Technol, Mat Phys Res, Murray Hill, NJ 07974 USA. RP Markelz, AG (reprint author), SUNY Buffalo, Dept Phys, Buffalo, NY 14260 USA. RI Roitberg, Adrian/A-2378-2009; OI Markelz, Andrea/0000-0003-0443-4319 NR 24 TC 437 Z9 468 U1 17 U2 152 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 MAR 31 PY 2000 VL 320 IS 1-2 BP 42 EP 48 DI 10.1016/S0009-2614(00)00227-X PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 299RG UT WOS:000086211200008 ER PT J AU Battle, M Bender, ML Tans, PP White, JWC Ellis, JT Conway, T Francey, RJ AF Battle, M Bender, ML Tans, PP White, JWC Ellis, JT Conway, T Francey, RJ TI Global carbon sinks and their variability inferred from atmospheric O-2 and delta C-13 SO SCIENCE LA English DT Article ID CO2; CYCLE; AIR; DIOXIDE; OXYGEN; RATIO AB Recent time-series measurements of atmospheric O-2 show that the land biosphere and world oceans annually sequestered 1.4 +/- 0.8 and 2.0 +/- 0.6 gigatons of carbon, respectively between mid-1991 and mid-1997. The rapid storage of carbon by the Land biosphere from 1991 to 1997 contrasts with the 1980s, when the land biosphere was approximately neutral. Comparison with measurements of delta(13)CO(2) implies an isotopic flux of 89 +/- 21 gigatons of carbon per mil per year, in agreement with model- and inventory-based estimates of this flux. Both the delta(13)C and the O-2 data show significant interannual variability in carbon storage over the period of record. The general agreement of the independent estimates from O-2 and delta(13)C is a robust signal of variable carbon uptake by both the Land biosphere and the oceans. C1 Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. CSIRO, Div Atmospher Res, Mordialloc, Vic 3195, Australia. RP Battle, M (reprint author), Bowdoin Coll, Dept Phys & Astron, 8800 Coll Stn, Brunswick, ME 04011 USA. RI White, James/A-7845-2009 OI White, James/0000-0001-6041-4684 NR 29 TC 323 Z9 360 U1 7 U2 59 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 MAR 31 PY 2000 VL 287 IS 5462 BP 2467 EP 2470 DI 10.1126/science.287.5462.2467 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 299MK UT WOS:000086202200039 PM 10741962 ER PT J AU Kilic, C Yildirim, T Mehrez, H Ciraci, S AF Kilic, C Yildirim, T Mehrez, H Ciraci, S TI A first-principles study of the structure and dynamics of C8H8, Si8H8, and Ge8H8 molecules SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SOLID CUBANE; DENSITY; ENERGY AB We present a first-principles study to elucidate the nature of the bonding, stability, energetics, and dynamics of individual X8H8 molecules (X = C, Si, Ge). The results obtained from both "local basis" and "pseudopotential" ab initio methods are in good agreement with the experimental data that exists for cubane (C8H8). The trends among these molecules are reminiscent of those prevailing in the bulk solids of C, Si, and Ge. High-temperature dynamics and fragmentation of X8H8 were studied by the quantum molecular dynamics method which shows that at high temperatures cubane is transformed to the 8-fold ring structure of cyclooctotetraene. C1 NIST, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Bilkent Univ, Dept Phys, TR-06533 Ankara, Turkey. McGill Univ, Dept Phys, Quebec City, PQ, Canada. RP Yildirim, T (reprint author), NIST, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI yildirim, taner/A-1290-2009; Kilic, Cetin/E-1336-2011 OI Kilic, Cetin/0000-0003-2690-4940 NR 25 TC 13 Z9 13 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 30 PY 2000 VL 104 IS 12 BP 2724 EP 2728 DI 10.1021/jp992705x PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 299ML UT WOS:000086202300027 ER PT J AU Druyan, LM Fulakeza, MB Thiaw, W AF Druyan, LM Fulakeza, MB Thiaw, W TI Regional model simulations of African wave disturbances SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SURFACE-TEMPERATURE; EASTERLY WAVES; PHASE III; SENSITIVITY; CLIMATE; PARAMETERIZATION; PRECIPITATION; CONVECTION; MOISTURE; RAINFALL AB A regional climate simulation model is run at 50 km horizontal resolution over West Africa to study synoptic systems, such as African wave disturbances (AWDs). The study examines the results of 18 simulations, the longest of them covering the period August 8-15, 1988. Simulations were initialized with European Center for Medium-Range Weather Forecasts (ECMWF) gridded analysis data which also supply the lateral boundary conditions. Daily means of 700 mbar circulation and other model diagnostics are compared with ECMWF and National Centers for Environmental Prediction analyses to assess the skill of the model in simulating the evolution of synoptic systems. Trajectories of AWDs are tracked on time-longitude cross sections of 700 mbar vorticity, lower tropospheric divergence and precipitation rates. Cloud clusters on satellite imagery relate rather well to synoptic features on observational analyses as well as to spatial patterns of rain gage measurements but not consistently to simulated precipitation, Movement of major AWDs and the generation of new waves are handled realistically by the model. Model dynamics and physics appear to be more important than lateral boundary conditions in determining the course of simulations. C1 Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. NOAA, Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD 20746 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Acad Sci, Natl Res Council, Washington, DC 20418 USA. RP Druyan, LM (reprint author), Columbia Univ, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10025 USA. EM ldruyan@giss.nasa.gov; mfulakeza@giss.nasa.gov; wd53wt@ncep.noaa.gov NR 29 TC 14 Z9 14 U1 0 U2 0 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 MAR 27 PY 2000 VL 105 IS D6 BP 7231 EP 7255 DI 10.1029/2000JD900017 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 297QW UT WOS:000086095000013 ER PT J AU Santer, BD Wigley, TML Boyle, JS Gaffen, DJ Hnilo, JJ Nychka, D Parker, DE Taylor, KE AF Santer, BD Wigley, TML Boyle, JS Gaffen, DJ Hnilo, JJ Nychka, D Parker, DE Taylor, KE TI Statistical significance of trends and trend differences in layer-average atmospheric temperature time series SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CLIMATE-CHANGE; RADIOSONDE VALIDATION; SATELLITE; FINGERPRINT; PRECISION; ANOMALIES; OZONE AB This paper examines trend uncertainties in layer average free atmosphere temperatures arising from the use of different trend estimation methods. It also considers statistical issues that arise in assessing the significance of individual trends and of trend differences between data sets. Possible causes of these trends are not addressed. We use data from satellite and radiosonde measurements and from two reanalysis projects. To facilitate intercomparison, we compute from reanalyses and radiosonde data temperatures equivalent to those from the satellite-based Microwave Sounding Unit (MSU). We compare linear trends based on minimization of absolute deviations (LA) and minimization of squared deviations (LS). Differences are generally less than 0.05 degrees C/decade over 1959-1996. Over 1979-1993, they exceed 0.10 degrees C/decade for lower tropospheric time series and 0.15 degrees C/decade for the lower stratosphere. Trend fitting by the LA method can degrade the lower-tropospheric trend agreement of 0.03 degrees C/decade (over 1979-1996) previously reported for the MSU and radiosonde data. In assessing trend significance we employ two methods to account for temporal autocorrelation effects. With our preferred method, virtually none of the individual 1979-1993 trends in deep-layer temperatures are significantly different from zero. To examine trend differences between data sets we compute 95% confidence intervals for individual trends and show that these overlap for almost all data sets considered. Confidence intervals for lower-tropospheric trends encompass both zero and the model-projected trends due to anthropogenic effects. We also test the significance of a trend in d(t), the time series of differences between a pair of data sets. Use of d(t) removes variability common to both time series and facilitates identification of small trend differences. This more discerning test reveals that roughly 30% of the data set comparisons have significant differences in lower-tropospheric trends, primarily related to differences in measurement system. Our study gives empirical estimates of statistical uncertainties in recent atmospheric temperature trends. These estimates and the simple significance testing framework used here facilitate the interpretation of previous temperature trend comparisons involving satellite, radiosonde, and reanalysis data sets. C1 Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, Livermore, CA 94550 USA. NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. United Kingdom Meteorol Off, Hadley Ctr Climate Predict & Res, Bracknell, Berks, England. RP Santer, BD (reprint author), Lawrence Livermore Natl Lab, Program Climate Model Diag & Intercomparison, POB 808,Mail Stop L-264, Livermore, CA 94550 USA. EM bsanter@pcmdi.llnl.gov RI Wigley, Tom/B-4705-2008; Taylor, Karl/F-7290-2011; Santer, Benjamin/F-9781-2011 OI Taylor, Karl/0000-0002-6491-2135; NR 50 TC 291 Z9 300 U1 4 U2 41 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 MAR 27 PY 2000 VL 105 IS D6 BP 7337 EP 7356 DI 10.1029/1999JD901105 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 297QW UT WOS:000086095000019 ER PT J AU Mazur, V AF Mazur, V TI Comment on "'Spider' lightning in intracloud and positive cloud-to-ground flashes" by Vladislav Mazur, Xuan-Min Shao, and Paul R. Krehbiel - Reply SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material C1 Natl Severe Storms Lab, Norman, OK 73069 USA. RP Mazur, V (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. EM mazur@nssl.noaa.gov NR 7 TC 1 Z9 1 U1 2 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 27 PY 2000 VL 105 IS D6 BP 7401 EP 7402 DI 10.1029/2000JD900021 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 297QW UT WOS:000086095000025 ER PT J AU Andersen, WC Noll, BC Sievers, RE Lagalante, AF Bruno, TJ AF Andersen, WC Noll, BC Sievers, RE Lagalante, AF Bruno, TJ TI Lanthanide chelates of 2,2,7-trimethyl-3,5-ogtaneoionate: Crystal structures and solubility in supercritical carbon dioxide. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Boulder, CO 80303 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 582-INOR BP U860 EP U860 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246104715 ER PT J AU Berman, HM Westbrook, J Bourne, P Weissig, H Gilliland, G Bhat, TN AF Berman, HM Westbrook, J Bourne, P Weissig, H Gilliland, G Bhat, TN TI Past, present, and future of the protein data bank as an enabling resource. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Rutgers State Univ, Dept Chem, Piscataway, NJ 08854 USA. Univ Calif San Diego, San Diego Supercomp Ctr, La Jolla, CA 92093 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Bourne, Philip/C-2073-2008 NR 0 TC 1 Z9 1 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 185-ANYL BP U112 EP U112 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246100502 ER PT J AU Boulter, JE Middlebrook, AM Murphy, DM Birks, JW AF Boulter, JE Middlebrook, AM Murphy, DM Birks, JW TI Characterization of a low-pressure exchanging virtual impactor for in situ analysis of atmospheric aerosols. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. EM boulterj@ucsu.colorado.edu RI Birks, John/H-7451-2013 OI Birks, John/0000-0003-1691-1354 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 255-PHYS BP U316 EP U316 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201714 ER PT J AU Brown, SS Burkholder, JB Talukdar, RK Ravishankara, AR Bianco, R Hynes, JT AF Brown, SS Burkholder, JB Talukdar, RK Ravishankara, AR Bianco, R Hynes, JT TI Mechanistic study of the reaction of hydroxyl radicals with nitric acid: Isotopically substituted reactions, product yields, and comparison to theory. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 61-PHYS BP U276 EP U277 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201520 ER PT J AU Burke, TC Dickens, SH Floyd, CJE AF Burke, TC Dickens, SH Floyd, CJE TI Investigation of 1,14-tetradecanediol dimethacrylate as a comonomer for dental applications. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Union Univ, Dept Chem Phys, Jackson, TN 38305 USA. NIST, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 440-CHED BP U353 EP U353 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101831 ER PT J AU Cessna, JT Karam, LR Coursey, BM AF Cessna, JT Karam, LR Coursey, BM TI Experimentally-determined dose calibrator settings for a yttrium-90 radioimmunotherapy agent. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Radioact Grp, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 126-NUCL BP U85 EP U85 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246200463 ER PT J AU Coxon, B AF Coxon, B TI Boat conformations: Analysis and simulation of the complex H-1 NMR spectrum of methyl 2,6 : 3,4-dianhydro-alpha-D-altropyranoside revisited. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 87-CARB BP U250 EP U250 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101199 ER PT J AU Diallo, MS Glinka, CJ Hernandez, Y Goddard, WA Johnson, JH AF Diallo, MS Glinka, CJ Hernandez, Y Goddard, WA Johnson, JH TI Structure and properties of aquatic colloids: Smell-angle neutron-scattering and dynamic light-scattering investigations of Suwanee River fulvic acid in aqueous solutions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 CALTECH, Washington, DC 20059 USA. Howard Univ, Dept Civil Engn, Washington, DC 20059 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. CALTECH, Beckman Inst, Mat & Proc Simulat Ctr, Pasadena, CA 91125 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 169-ENVR BP U645 EP U645 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246103503 ER PT J AU Drohat, AC Stivers, JT AF Drohat, AC Stivers, JT TI Role of hydrogen bonding in transition-state stabilization by uracil DNA glycosylase. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Maryland, Maryland Biotechnol Inst, Rockville, MD 20850 USA. NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 65-BIOL BP U135 EP U135 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246100621 ER PT J AU Durst, HD McGarvey, DJ Mallard, WG Stuff, JR Williams, BR AF Durst, HD McGarvey, DJ Mallard, WG Stuff, JR Williams, BR TI Retention indices and mass spectral study of some in situ-generated chemical warfare agents. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Edgewood Chem & Biol Ctr, Soldier Biol & Chem Command, Aberdeen Proving Ground, MD 21010 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 91-ANYL BP U98 EP U99 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246100415 ER PT J AU Gao, M Breit, M von Plessen, G Lemmer, U Feldmann, J Cundiff, S AF Gao, M Breit, M von Plessen, G Lemmer, U Feldmann, J Cundiff, S TI Monitoring the buildup of layer-by-layer self-assembled films using second harmonic generation. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Munich, Dept Phys & CeNS, Photon & Optoelect Grp, D-80799 Munich, Germany. Univ Colorado, NIST, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Cundiff, Steven/B-4974-2009; Lemmer, Uli/F-8257-2012 OI Cundiff, Steven/0000-0002-7119-5197; Lemmer, Uli/0000-0001-9892-329X 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 185-COLL BP U530 EP U530 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246102879 ER PT J AU Gilman, JW Harris, RH Jackson, CL Morgan, AB Brassell, LD Hunter, DL AF Gilman, JW Harris, RH Jackson, CL Morgan, AB Brassell, LD Hunter, DL TI Phenolic cyanate ester clay nanocomposites: Effect of ammonium ion structure on flammability and nanodispersion. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Mat Fire Res Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. So Clay Prod Inc, Gonzales, TX 78629 USA. RI Morgan, Alexander/A-9672-2009 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 217-PMSE BP U497 EP U497 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202796 ER PT J AU Goldschmidt, RJ Guttman, CM AF Goldschmidt, RJ Guttman, CM TI Response saturation of polystyrene in MALDI. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20874 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 53-POLY BP U363 EP U363 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202004 ER PT J AU Gonzalez, CA Allison, TC AF Gonzalez, CA Allison, TC TI Next-generation molecular optimization software: Development of a modern platform for potential energy surface characterization. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Computat Chem Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Expt Kinet & Thermodynam Grp, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 328-PHYS BP U327 EP U327 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201787 ER PT J AU Gonzalez, CA Louis, F Allison, TC Huie, RE Kurylo, MJ AF Gonzalez, CA Louis, F Allison, TC Huie, RE Kurylo, MJ TI Toward the implementation of a computational chemistry screening tool for the kinetics of H-atom abstraction reactions: Search for efficient theoretical methodologies. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Computat Chem Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Expt Kinet & Thermodynam Grp, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 239-PHYS BP U313 EP U313 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201698 ER PT J AU Greenberg, RR AF Greenberg, RR TI High-accuracy materials characterization using neutron-activation analysis. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 212-ANYL BP U116 EP U116 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246100528 ER PT J AU Greenblatt, M Fawcett, ID Croft, M Bendersky, L AF Greenblatt, M Fawcett, ID Croft, M Bendersky, L TI Properties of the electron-doped layered manganates, La2-2XCa1+2XMn2O7 (0.6 <= X <= 1.0). SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Rutgers State Univ, Dept Chem, Piscataway, NJ 08854 USA. NIST, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 608-INOR BP U864 EP U864 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246104741 ER PT J AU Grohn, F Bauer, BJ Amis, EJ AF Grohn, F Bauer, BJ Amis, EJ TI Templating nanocrystals with dendrimers: A mesoscopic model system. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 295-POLY BP U400 EP U400 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202245 ER PT J AU Gu, X VanLandingham, M Raghavan, D Nguyen, T AF Gu, X VanLandingham, M Raghavan, D Nguyen, T TI Mapping heterogeneity in polymeric materials using atomic force microscopy: Phase-imaging and nanoindentation. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Howard Univ, Dept Chem, Washington, DC 20059 USA. NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 58-PMSE BP U474 EP U474 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202638 ER PT J AU Guttman, CM Wetzel, SJ Wallace, WE Blair, WR Goldschmidt, RM VanderHart, D Fanconi, BM AF Guttman, CM Wetzel, SJ Wallace, WE Blair, WR Goldschmidt, RM VanderHart, D Fanconi, BM TI Determination of the molecular-mass distribution of a narrow polydispersity polystyrene by MALDI-TOF MS: Interlaboratory comparison. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 281-POLY BP U398 EP U398 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202232 ER PT J AU Heimer, TA Heilweil, EJ AF Heimer, TA Heilweil, EJ TI Transient absorbance studies of ionic and radical polymerization of 1-hexene by zirconocene catalysts. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 320-INOR BP U819 EP U820 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246104455 ER PT J AU Ho, DL Briber, RM Glinka, CJ AF Ho, DL Briber, RM Glinka, CJ TI Studies on organically modified clays using scattering techniques. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI Briber, Robert/A-3588-2012 OI Briber, Robert/0000-0002-8358-5942 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 200-PMSE BP U495 EP U495 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202780 ER PT J AU Holden, MJ Mayhew, MP Vilker, VL AF Holden, MJ Mayhew, MP Vilker, VL TI Chorisimate pyruvate lyase: Engineering a stable enzyme for conversion of chorismate to p-hyoroxybenzoate. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 292-BIOT BP U216 EP U216 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101016 ER PT J AU Huang, TH Warsinke, FW Kuwana, T AF Huang, TH Warsinke, FW Kuwana, T TI Determination of thiols at enzyme-modified electrodes based on the inhibition of enzymatic substrate-recycling. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Proc Sensing Grp, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Univ Potsdam, Dept Analyt Biochem, Luckenwalde, Germany. Univ Kansas, Dept Chem, Lawrence, KS 66045 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 693-INOR BP U877 EP U877 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246104826 ER PT J AU Huie, RE Louis, F Gonzalez, CA Orkin, VL Kurylo, MJ AF Huie, RE Louis, F Gonzalez, CA Orkin, VL Kurylo, MJ TI Ab initio quantum chemical treatment of the kinetics of h-atom abstraction reactions: Implementation and application of a theoretical screening tool for atmospheric chemistry. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Expt Kinet & Thermodynam Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Computat Chem Grp, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 134-ENVR BP U639 EP U639 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246103470 ER PT J AU Irikura, KK Johnson, RD AF Irikura, KK Johnson, RD TI Searching for chemistry on isopotentials. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 305-PHYS BP U323 EP U324 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201764 ER PT J AU Ivkov, R Papanek, P Gehring, PM Krishnamoorti, R AF Ivkov, R Papanek, P Gehring, PM Krishnamoorti, R TI Polymer dynamics in intercalated clay-polymer nanocomposites studied by inelastic neutron scattering. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Penn, Philadelphia, PA 19104 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 78-PMSE BP U477 EP U477 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202658 ER PT J AU Jeon, HS Nakatani, AI AF Jeon, HS Nakatani, AI TI Smear-induced novel structure in phase-separated polybutadiene/polyisoprene blends. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 New Mexico Inst Min & Technol, Dept Petr & Chem Engn, Socorro, NM 87801 USA. NIST, Div Polymers, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 159-PMSE BP U489 EP U489 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202739 ER PT J AU Jeon, HS Nakatani, AI Han, CC Colby, RH AF Jeon, HS Nakatani, AI Han, CC Colby, RH TI Effects of domain interfaces on the rheological properties of polybutadiene/polyisoprene blends. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 New Mexico Inst Min & Technol, Dept Chem & Petr Engn, Socorro, NM 87801 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 6-PMSE BP U466 EP U466 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202586 ER PT J AU Johnson, RD AF Johnson, RD TI Computational chemistry comparison and benchmark database. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Computat Chem Grp, Gaithersburg, MD 20899 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 154-COMP BP U611 EP U611 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246103320 ER PT J AU Karim, A Douglas, JF AF Karim, A Douglas, JF TI Polymer-surface interactions in nanofilled polymers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 73-PMSE BP U476 EP U476 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202653 ER PT J AU Kim, G Jackson, CL Prosa, TJ Liu, D Bauer, BJ AF Kim, G Jackson, CL Prosa, TJ Liu, D Bauer, BJ TI Nanocomposites of molecularly dispersed polyamidoamine (PAMAM) dendrimers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymer, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 241-PMSE BP U501 EP U501 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202820 ER PT J AU Kim, SD Boczar, EM Bauer, BJ Klein, A Sperling, LH AF Kim, SD Boczar, EM Bauer, BJ Klein, A Sperling, LH TI Direct comparison of SANS and DET for polymer diffusion during polystyrene latex-film formation. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Lehigh Univ, Ctr Polymer Sci & Engn, Bethlehem, PA 18015 USA. Rohm & Haas Co, Spring House, PA 19477 USA. NIST, Polymer Div, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 61-POLY BP U365 EP U365 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202012 ER PT J AU Klemm, RB Thorn, RP Stief, LJ Buckley, TJ AF Klemm, RB Thorn, RP Stief, LJ Buckley, TJ TI Heat of formation of OBrO: An experimental photoionization study. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 218-PHYS BP U310 EP U310 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201677 ER PT J AU Kuck, LR Smith, T Balsley, BB Helmig, D Jensen, ML Bognar, JA Birks, JW Conway, TJ Tans, PP Davis, K Arrieta, RV Rodriquez, R AF Kuck, LR Smith, T Balsley, BB Helmig, D Jensen, ML Bognar, JA Birks, JW Conway, TJ Tans, PP Davis, K Arrieta, RV Rodriquez, R TI Measurements of landscape-scale fluxes of carbon dioxide in the Peruvian Amazon by vertical profiling through the convective boundary layer. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, CIRES, Boulder, CO 80309 USA. Natl Ocean & Atmospher Adm Climate & Monitoring D, Boulder, CO 80309 USA. Univ Minnesota, Dept Soil Water & Climate, Minneapolis, MN 55455 USA. RI Birks, John/H-7451-2013 OI Birks, John/0000-0003-1691-1354 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 226-PHYS BP U311 EP U311 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201685 ER PT J AU Laursen, S Mernitz, H AF Laursen, S Mernitz, H TI Would you like fries with that? The fuss about fats in our diet. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA, Boulder, CO 80303 USA. Beloit Coll, Beloit, WI 53511 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 54-CHED BP U297 EP U297 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101446 ER PT J AU Laursen, SL Ravishankara, AR AF Laursen, SL Ravishankara, AR TI Rates of reaction of OH with fluoroalkene CFC substitutes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 235-PHYS BP U313 EP U313 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201694 ER PT J AU Louis, F Gonzalez, CA Huie, RE Kurylo, MJ Sawerysyn, JP AF Louis, F Gonzalez, CA Huie, RE Kurylo, MJ Sawerysyn, JP TI Ab initio study of the kinetics of the reactions of ClO radicals with CHXCl4-X(X=1-4) over the temperature range 200-2500 k. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Expt Kinet & Thermodynam Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Computat Chem Grp, Gaithersburg, MD 20899 USA. Univ Sci & Tech Lille Flandres Artois, CNRS, UMR 8522, Lab Cinet & Chim Combust, F-59655 Villeneuve Dascq, France. 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 212-PHYS BP U309 EP U309 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201671 ER PT J AU Martin, JW Nguyen, T Byrd, E Embree, N AF Martin, JW Nguyen, T Byrd, E Embree, N TI Estimation of absorbed photolytic dosage and quantum yield using UV-vis and FTIR spectroscopies. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Organ Bldg Mat Grp, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 141-PMSE BP U486 EP U487 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202721 ER PT J AU Mayhew, MP Tewari, Y Holden, MJ Roitberg, AE Vilker, VL AF Mayhew, MP Tewari, Y Holden, MJ Roitberg, AE Vilker, VL TI Hydroxylation of benzocycloarenes with P450: Predicting the dependence of catalytic rate and NADH coupling on arene ring size with a spectrophotometric assay. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 285-BIOT BP U215 EP U215 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101010 ER PT J AU Meredith, JC Karim, A Amis, EJ AF Meredith, JC Karim, A Amis, EJ TI Combinatorial measurements for polymeric coatings. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20878 USA. RI Meredith, Carson/B-3323-2009 OI Meredith, Carson/0000-0003-2519-5003 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 3-MTLS BP U552 EP U552 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246203076 ER PT J AU Morgan, AB Gilman, JW Jackson, CL AF Morgan, AB Gilman, JW Jackson, CL TI Characterization of polymer-clay nanocomposites: XRD vs. TEM. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. NIST, Div Polymer, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RI Morgan, Alexander/A-9672-2009 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 201-PMSE BP U495 EP U495 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202781 ER PT J AU Nesbitt, DJ AF Nesbitt, DJ TI Probing quantum state-to-state dynamics: From clusters to chemical reactions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, NIST, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 28-PHYS BP U272 EP U272 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201487 ER PT J AU Peiffer, DG Rabeony, M Tang, B Zhang, Y Ge, S Rafailovich, M Sokolov, J Dias, JA McElrath, KO Lin, M Satija, S AF Peiffer, DG Rabeony, M Tang, B Zhang, Y Ge, S Rafailovich, M Sokolov, J Dias, JA McElrath, KO Lin, M Satija, S TI Phase behaviour and interfacial characteristics of poly(isobutylene)-co-4-methylstyrene/general purpose rubber blends. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 ExxonMobil R&E Co, Annandale, NJ 08801 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. ExxonMobil Chem Co, Baytown, TX 77520 USA. NIST, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 18-RUBB BP U512 EP U512 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202869 ER PT J AU Peiris, SM Russell, TP Balzaretti, NM Gonzalez, EJ Piermarini, GJ AF Peiris, SM Russell, TP Balzaretti, NM Gonzalez, EJ Piermarini, GJ TI High-pressure resistive-heating technique for gem anvil cells. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 USN, Res Lab, High Energy Mat Sect, Washington, DC 20375 USA. UFRGS, Inst Fis, Porto Alegre, RS, Brazil. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Balzaretti, Naira/L-3417-2014 OI Balzaretti, Naira/0000-0003-2797-8618 NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 473-PHYS BP U348 EP U348 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201931 ER PT J AU Piccoli, RF Roensch, FR Dasher, DH Read, S Hameedi, MJ Efurd, DW AF Piccoli, RF Roensch, FR Dasher, DH Read, S Hameedi, MJ Efurd, DW TI Determination of actinide levels in Arctic river sediments. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Ocean & Atmospher Adm, Silver Spring, MD 20910 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 175-ENVR BP U646 EP U646 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246103509 ER PT J AU Solomon, S AF Solomon, S TI Atmospheric spectroscopy of key molecules highlighted by H. S. Johnston's work. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA, Aeron Lab, Boulder, CO 80303 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 57-PHYS BP U276 EP U276 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201516 ER PT J AU Solomon, S AF Solomon, S TI Ozone hole: Yesterday, today, and tomorrow. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA, Aeron Lab, Boulder, CO 80303 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 27-PHYS BP U272 EP U272 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201486 ER PT J AU Stevens, WJ AF Stevens, WJ TI Effective core potential development and applications. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 1-COMP BP U589 EP U589 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246103168 ER PT J AU Tellez, CM Cole, KD AF Tellez, CM Cole, KD TI Preparative purification and library construction of BAC DNA using reversible electrophoresis gels. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Bioproc Engn Grp, Div Biotechnol, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 206-BIOT BP U192 EP U192 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246100933 ER PT J AU Tsai, AM Neumann, DA Bell, LN AF Tsai, AM Neumann, DA Bell, LN TI Effect of glycerol on the thermal stability of lysozyme powder: A neutron scattering study. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Auburn Univ, Auburn, AL 36849 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 352-BIOT BP U226 EP U226 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101076 ER PT J AU Tsang, W Mokrushin, V AF Tsang, W Mokrushin, V TI Software for the estimation of rates of gas-phase processes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 1024-CHED BP U442 EP U442 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246102414 ER PT J AU Vanderah, DJ Pham, CT Silin, V Meuse, CW AF Vanderah, DJ Pham, CT Silin, V Meuse, CW TI Characterization of a series of self-assembled monolayers of alkylated 1-thia(ethylene oxides)(4-8) on gold. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21250 USA. Georgetown Univ, Washington, DC 20057 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 265-CHED BP U327 EP U327 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246101656 ER PT J AU VanderHart, DL Nyden, MR Alamo, RG Mandelkern, L AF VanderHart, DL Nyden, MR Alamo, RG Mandelkern, L TI Incorporation of stereo-, regio-, and comonomer defects into the crystalline regions of isotactic polypropylene: Results from NMR, molecular dynamics, and chemical-shift calculations. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Florida State Univ, Dept Chem Engn, Tallahassee, FL 32310 USA. Florida State Univ, Dept Chem, Tallahassee, FL 32306 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 48-PMSE BP U472 EP U472 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202628 ER PT J AU Viers, BD Bauer, BJ Akpalu, Y Grohn, F Liu, D Kim, G AF Viers, BD Bauer, BJ Akpalu, Y Grohn, F Liu, D Kim, G TI Hydrogels formed by end-linking PEG to dendrimer cross-link agents. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Polymer Blends & Proc Grp, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 526-POLY BP U444 EP U444 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246202474 ER PT J AU Vilker, VL Reipa, V Mayhew, M Holden, MJ AF Vilker, VL Reipa, V Mayhew, M Holden, MJ TI Temperature dependence of the formal reduction potential of putidaredoxin. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 444-INOR BP U838 EP U838 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246104578 ER PT J AU Wallace, WE Guttman, CM Antonucci, JM AF Wallace, WE Guttman, CM Antonucci, JM TI MALDI-TOF mass spectrometry of polymeric silsesquioxanes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 20-POLY BP U358 EP U358 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246201972 ER PT J AU Xu, J Lee, CS Locascio, LE AF Xu, J Lee, CS Locascio, LE TI Isoelectric focusing of green fluorescence proteins in plastic microfluid channels. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Maryland, College Pk, MD 20740 USA. Natl Inst Stand, Gaithersburg, MD USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 9-ANYL BP U86 EP U86 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UV UT WOS:000087246100336 ER PT J AU Zimmerman, BE Unterweger, MP AF Zimmerman, BE Unterweger, MP TI Standardization of the radiotherapy nuclide lutetium-177. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 127-NUCL BP U85 EP U85 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246200464 ER PT J AU Zimmerman, BE Cessna, JT Coursey, BM Karam, LR Golas, DB AF Zimmerman, BE Cessna, JT Coursey, BM Karam, LR Golas, DB TI Role of the National Institute of Standards and Technology in measurement assurance for the radiopharmaceutical industry in the United States. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Nucl Energy Inst, Washington, DC 20006 USA. Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 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 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 26 PY 2000 VL 219 MA 125-NUCL BP U85 EP U85 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 317UW UT WOS:000087246200462 ER PT J AU Huo, WM Kim, YK AF Huo, WM Kim, YK TI Use of relativistic effective core potentials in the calculation of total electron-impact ionization cross-sections SO CHEMICAL PHYSICS LETTERS LA English DT Article ID RARE-GAS ATOMS; WAVE-FUNCTIONS; BASIS-SETS; R-MATRIX; THRESHOLD; HYDROGEN; SCATTERING; MOLECULES; ENERGIES; DIPOLE AB The binary-encounter-Bethe (BEB) model of Kim and Rudd for total ionization cross-sections by electron impact is re-examined when the target is an atom with principal quantum number n greater than or equal to 3, or a molecule consisting of one or mon atoms with n greater than or equal to 3. It is shown that the use of relativistic effective core potential (RECP) for heavy atoms removes the need for the empirical scaling used previously. BEB cross-sections of Ar, Kr, Xe, Cl, Pr, I, and WF6 calculated using RECP are found to be in good agreement with available experimental data, especially in the low-energy region. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Huo, WM (reprint author), NASA, Ames Res Ctr, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 31 TC 18 Z9 18 U1 0 U2 6 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 MAR 24 PY 2000 VL 319 IS 5-6 BP 576 EP 586 DI 10.1016/S0009-2614(00)00150-0 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 298CL UT WOS:000086121700024 ER PT J AU Levitus, S Antonov, JI Boyer, TP Stephens, C AF Levitus, S Antonov, JI Boyer, TP Stephens, C TI Warming of the world ocean SO SCIENCE LA English DT Article ID SEA-SURFACE TEMPERATURE; STRATOSPHERIC CIRCULATION; NORTHERN-HEMISPHERE; INTERMEDIATE; VARIABILITY; ATLANTIC; WINTER AB We quantify the interannual-to-decadal variability of the heat content (mean temperature) of the world ocean from the surface through 3000-meter depth for the period 1948 to 1998. The heat content of the world ocean increased by similar to 2 X 10(23) joules between the mid-1950s and mid-1990s, representing a volume mean warming of 0.06 degrees C. This corresponds to a warming rate of 0.3 watt per meter squared (per unit area of faith's surface). Substantial changes in heat content occurred in the 300- to 1000-meter layers of each ocean and in depths greater than 1000 meters of the North Atlantic. The global volume mean temperature increase for the 0- to 300-meter layer was 0.31 degrees C, corresponding to an increase in heat content for this Layer of similar to 10(23) joules between the mid-1950s and mid-1990s. The Atlantic and Pacific Oceans have undergone a net warming since the 1950s and the Indian Ocean has warmed since the mid-1960s, although the warming is not monotonic. C1 NOAA, NODC, Silver Spring, MD 20910 USA. RP Levitus, S (reprint author), NOAA, NODC, E-OC5,1315 E West Highway, Silver Spring, MD 20910 USA. EM slevitus@nodc.noaa.gov NR 30 TC 724 Z9 770 U1 20 U2 156 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 MAR 24 PY 2000 VL 287 IS 5461 BP 2225 EP 2229 DI 10.1126/science.287.5461.2225 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 296WE UT WOS:000086049100040 ER PT J AU Delworth, TL Knutson, TR AF Delworth, TL Knutson, TR TI Simulation of early 20th century global warming SO SCIENCE LA English DT Article ID OCEAN-ATMOSPHERE MODEL; SURFACE-TEMPERATURE; GREENHOUSE GASES; NORTH-ATLANTIC; COUPLED MODEL; CLIMATE; VARIABILITY; OSCILLATION; AEROSOLS; SEA AB The observed global warming of the past century occurred primarily in two distinct 20-year periods, from 1925 to 1944 and from 1978 to the present. Although the Latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear because this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) forcing. Results from a set of six integrations of a coupled ocean-atmosphere climate model suggest that the warming of the early 20th century could have resulted from a combination of human-induced radiative forcing and an unusually Large realization of internal multidecadal variability of the coupled ocean-atmosphere system. This conclusion is dependent on the model's climate sensitivity, internal variability, and the specification of the time-varying human-induced radiative forcing. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Delworth, TL (reprint author), NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. EM td@gfdl.gov RI Delworth, Thomas/C-5191-2014; Bindoff, Nathaniel/C-8050-2011 OI Bindoff, Nathaniel/0000-0001-5662-9519 NR 26 TC 157 Z9 169 U1 4 U2 28 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAR 24 PY 2000 VL 287 IS 5461 BP 2246 EP 2250 DI 10.1126/science.287.5461.2246 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 296WE UT WOS:000086049100046 ER PT J AU Irikura, KK Johnson, RD AF Irikura, KK Johnson, RD TI Predicting unexpected chemical reactions by isopotential searching SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID AB-INITIO; THERMAL-DECOMPOSITION AB The reactions of a chemical system are dictated by the corresponding potential energy surface (PES). Since reasonably accurate PESs are now available from quantum chemical calculations, a great deal of chemistry can, in principle, be predicted using existing techniques. We describe a few algorithms for finding low-energy exit channels from a well in a PES without foreknowledge of the products. Several illustrative applications are provided, including (1) unimolecular rearrangement of benzocyclohex-1-en-3-yne and (2) bimolecular reaction between ammonia and dichlorosilane. These two systems were chosen because their reactions were previously found to have been predicted incorrectly. In both cases, the correct mechanisms are recovered using isopotential searching strategies. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Irikura, KK (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 11 TC 18 Z9 18 U1 0 U2 2 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 MAR 23 PY 2000 VL 104 IS 11 BP 2191 EP 2194 DI 10.1021/jp992557a PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 296LF UT WOS:000086025300006 ER PT J AU VanderHart, DL Feng, Y Han, CC Weiss, RA AF VanderHart, DL Feng, Y Han, CC Weiss, RA TI Morphological characterization of blends of metal-sulfonated poly(styrene) and a methylated poly(amide) by solid state NMR SO MACROMOLECULES LA English DT Article ID PROTON SPIN-DIFFUSION; X-RAY-SCATTERING; POLYMER BLENDS; POLYSTYRENE IONOMERS; IONOMER/POLYAMIDE BLENDS; CRYSTALLINE; COMPATIBILIZATION; POLARIZATION; COMPLEXATION; POLYAMIDE-6 AB Various blends of atactic, low-MW (approximate to 4000), metal-sulfonated poly(styrene) (MSPS) and a higher-MW (approximate to 25 000) poly(amide) (PA) were studied by solid-state C-13 and proton NMR techniques which include multiple-pulse irradiation, cross-polarization, and magic angle spinning. This study is an investigation of the morphology of these MSPS(n)/PA blends (n = 100 x mole fraction sulfonate = 2.3, 7.0, or 11.9) as functions of blend composition and sulfonation level. Unsulfonated PS and PA are incompatible and phase separate. Decoration with sulfonate groups promotes mixing of the blend components owing to strong, polar metal-sulfonate/amide interactions, Metal ions used were divalent Zn (diamagnetic) and Cu (paramagnetic), the latter ions having a significant influence on the protons. The PA, N,N'-dimethylethylene sebacamide, was N-methylated to weaken interactions between PA chains, thereby promoting mixing. Pure PA is semicrystalline, and intimate mixing prevents PA crystallization. C-13 CPMAS spectra were used to assay PA crystallinity. The stability of the blend morphology in the presence of water was also studied since water is expected to modify or compete with the polar interactions of the blend. Many of the experiments performed relied, for their interpretation, on the phenomenon of proton spin diffusion. For ZnSPS(11.9)/PA blends, mixing was quite intimate and PA crystallinity was suppressed for PA mass fractions of 0.5 and lower. PA crystallinity first appeared with a PA mass fraction of 0.65; however, this crystallinity was not the result of large-scale phase separation of the PA from the MSPS. Rather, PA crystallinity develops in the mixed MSPS/PA phase in such a way that each PA crystallite is surrounded by a mixed MSPS/PA phase. Larger PA mass fractions gave higher PA crystallinities. When PA crystallinity is present, there is an average periodicity of about 20-25 nm; moreover, the noncrystalline regions surrounding each crystallite have nonuniform composition in the sense that there is a buffer zone adjacent to the PA crystallites which is mainly PA in composition. A few blends involving ZnSPS(7.0) and ZnSPS(2.3) were also studied. Only the 75/25 ZnSPS(7.0)/PA blend seemed well mixed and noncrystalline. Compositional heterogeneities on scales larger than 20 nm were seen in the remaining blends. Certain CuSPS ionomers and blends, analogous to the Zn-containing materials, were studied in an attempt to resolve some ambiguities present in the interpretation of the data taken for the Zn-containing materials. Zn and Cu ions show similar affinities for the amide moieties; hence, the morphology for analogous Zn- and Cu-containing blends is expected to be similar. Mainly proton longitudinal relaxation was measured because it is sensitive to the presence of paramagnetic Cu. Two matters were pursued for the Cu-containing materials: First, the uniformity of Cu distribution was probed in pure CuSPS(11.9). Our T-1(H) analysis gave a variation by a factor of 1.3 in averaged Cu concentration, where the averaging was done over dimensions of 14 nm. Second. given that the 75/25 CuSPS(2.3)/PA blend exhibits large-scale phase separation, where one phase contains nearly all of the PA plus a small fraction of the SPS, we addressed the question whether the level of decorations for the SPS chains in this mixed phase was significantly above the 2.3% average. Our analysis did not support such a claim within the assumption that the morphologies of the Zn- and Cu-containing blends are the same. Toward an evaluation of paramagnetic Cu ions as aids for the elucidation of morphology in organic systems, several qualitative characteristics of the proton and C-13 relaxation are noted for these Cu-containing materials. Also, an estimate of the electron relaxation time, T-1(e) in CuSPS(11.9) is given as is the fraction (0.95) of observable protons using multiple-pulse techniques. T-1(e) is shown to vary strongly with overall Cu concentration in the pure ionomers and with the amount of water absorbed in the pure ionomer. T-1(e) also changes when Cu is bound to the amide moiety of PA. One cannot simply assume that the average Cu concentration and (1/T-1(H)) are proportional. A few annealing experiments also indicate that when the mole fraction of Cu is 7.0% or 2.3% in the ionomer, annealing seems to promote more clustering as though the cast films were not at their energy minima with respect to Cu-Cu interactions. Finally, in CuSPS(11.9), spin diffusion results indicate that the position of the SAXS maximum near q = 2 nm(-1) is consistent with the separation between paramagnetic centers, which centers, in turn, are estimated to consist of clusters of about 10 Cu sites. If cluster size diminishes with average Cu concentration, then data indicate that T-1(e) is a strong function of cluster size. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. Univ Connecticut, Dept Chem Engn, Storrs, CT 06269 USA. Univ Connecticut, Polymer Sci Program, Storrs, CT 06269 USA. RP VanderHart, DL (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 43 TC 18 Z9 18 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAR 21 PY 2000 VL 33 IS 6 BP 2206 EP 2227 DI 10.1021/ma991545k PG 22 WC Polymer Science SC Polymer Science GA 297GF UT WOS:000086073300043 ER PT J AU Lue, L AF Lue, L TI Volumetric behavior of athermal dendritic polymers: Monte Carlo simulation SO MACROMOLECULES LA English DT Article ID ANGLE NEUTRON-SCATTERING; INTEGRAL-EQUATION THEORY; HARD-SPHERE CHAINS; MOLECULAR-DYNAMICS; STARBURST DENDRIMERS; PAMAM DENDRIMERS; STATE; MACROMOLECULES; TRANSITION; VISCOSITY AB We present results of Monte Carlo simulations for dilute to concentrated solutions of athermal, homogeneous dendritic polymers. The dendritic polymers are composed of tangent hard-spheres and vary from generation 0 to generation 5. These simulations investigate the effect of hyperbranching on the structure and thermodynamics of polymer solutions. At low concentrations, dendritic polymers systems have a lower pressure than linear polymers of the same molecular weight, owing to the more compact architecture of the dendrimer. In the concentrated polymer regime, solutions containing low-generation dendrimers behave similarly to linear polymers, while those containing high-generation dendrimers have a pressure that increases more rapidly with concentration. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Lue, L (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, M-S 838,325 Broadway, Boulder, CO 80303 USA. RI Lue, Leo/E-7846-2011 OI Lue, Leo/0000-0002-4826-5337 NR 50 TC 32 Z9 35 U1 0 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 MAR 21 PY 2000 VL 33 IS 6 BP 2266 EP 2272 DI 10.1021/ma991340b PG 7 WC Polymer Science SC Polymer Science GA 297GF UT WOS:000086073300048 ER PT J AU Pipino, ACR AF Pipino, ACR TI Monolithic folded resonator for evanescent wave cavity ringdown spectroscopy SO APPLIED OPTICS LA English DT Article ID DOWN SPECTROSCOPY; ABSORPTION-MEASUREMENTS; DICHROISM; ORDER AB An optical resonator is characterized that employs both ultrahigh-reflective coated surfaces and total internal reflection to enable cavity ringdown spectroscopy of surfaces, films, and liquids. The monolithic folded design possesses a polarization-independent finesse that allows polarization-dependent phenomena, such as molecular orientation, to be probed. Although a restricted bandwidth (similar to 15% of the design wavelength) results from use of reflective coatings, the resonator provides high sensitivity and facile operation. A minimum detectable absorption of 2.2 X 10(-6) was obtained for single laser shots by use of multimode excitation at 530 nm with an excimer-pumped, pulsed dye laser. OCIS codes: 230.5750, 240.6490, 300.1030. C1 NIST, Proc Measurements Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Pipino, ACR (reprint author), NIST, Proc Measurements Div, Chem Sci & Technol Lab, 100 Bur Dr, Gaithersburg, MD 20899 USA. EM andrew.pipino@nist.gov NR 25 TC 42 Z9 43 U1 0 U2 8 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 MAR 20 PY 2000 VL 39 IS 9 BP 1449 EP 1453 DI 10.1364/AO.39.001449 PG 5 WC Optics SC Optics GA 295EM UT WOS:000085953800014 PM 18338031 ER PT J AU Pagano, I Linsky, JL Carkner, L Robinson, RD Woodgate, B Timothy, G AF Pagano, I Linsky, JL Carkner, L Robinson, RD Woodgate, B Timothy, G TI HST/STIS echelle spectra of the dM1e star AU Microscopii outside of flares SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : chromospheres; stars : coronae; stars : hare; ultraviolet : stars ID HIGH-RESOLUTION SPECTROGRAPH; OBSERVING STELLAR CORONAE; RS-CANUM-VENATICORUM; TRANSITION REGION; OUTER ATMOSPHERES; QUIET REGIONS; SOLAR CORONA; AR-LACERTAE; COOL STARS; O-IV AB We report on observations of the dM1e flare star AU Microscopii obtained with the Space Telescope Imaging Spectrograph (STIS) on 1998 September 6. A total of 10,105 s of observations were obtained with the medium-resolution E140M grating. We report here on the 9200 s of "quiescent" data when the star did not obviously flare. In this data set, we identify 142 emission lines from 28 species, including low-temperature chromospheric lines (e.g., C I, O I), transition-region lines (e.g., C II-IV, N IV, O III-V, Si II-IV), and the coronal line Fe XXI 1354 Angstrom. There are a number of intersystem lines that are useful for measuring electron densities. We discuss line redshifts and the broad wings of transition-region lines that provide evidence of microflare heating. We derive the emission-measure distribution and compare it with the solar one. We also discuss the shape and formation mechanisms of the He II 1640 Angstrom lines. The analysis of the flare data and of the interstellar absorption features seen in the H I, D I, C II, and O I resonance lines will be published elsewhere. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20034 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Nightsen Inc, Warwick, RI 02886 USA. Osserv Astrofis Catania, Catania, Italy. RP Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. EM ipagano@alpha4.ct.astro.it RI Pagano, Isabella/I-6934-2015 OI Pagano, Isabella/0000-0001-9573-4928 NR 61 TC 39 Z9 39 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2000 VL 532 IS 1 BP 497 EP 513 DI 10.1086/308559 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 301VF UT WOS:000086330400045 ER PT J AU Tewari, YB AF Tewari, YB TI Thermodynamics of the lipase-catalyzed transesterification of (-)-menthol and dodecyl dodecanoate in organic solvents SO JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC LA English DT Article DE 1-dodecanol; dodecyl dodecanoate; equilibrium constants; lipase; (-)-menthol; (-)-menthyl dodecanoate; organic solvents; partition coefficients; solubility ID SURFACTANT-COATED LIPASE; EQUILIBRIUM POSITION; ESTERIFICATION; MEDIA; ACID; MICROEMULSIONS; HYDROLYSIS; MENTHOL; ESTER AB The thermodynamics of the lipase-catalyzed transesterification reaction (-)-menthol(sln) + dodecyl dodecanoate(sln) = (-)-menthyl dodecanoate(sln) + 1-dodecanol(sln) have been studied. Equilibrium measurements were performed as a function of temperature with n-heptane, toluene and 2,2,4-trimethylpentane as solvents. The results of the equilibrium measurements were used to calculate the standard molar Gibbs energy Delta(r)G(m)(o), enthalpy Delta(r)H(m)(o) and entropy Delta(r)S(m)(o) changes for the above reaction in these three solvents at the temperature T = 298.15 K. The values of the Delta(r)G(m)(o) and Delta(r)H(m)(o) in these solvents ranged, respectively, from 1.5 to 2.6 kJ mol(-1) and from 0.2 to 4.0 kJ mol(-1). The (hexane + water) partition coefficients of the reactants and products were also determined at T = 298.15 K. A thermochemical cycle calculation was then used to calculate a value for the equilibrium constant K = (2.4 +/- 0.7) X 10(-3) and Delta(r)G(m)(o) = (14.9 +/- 0.7) kJ mol(-1) for the above reaction in water. However, the average value of the equilibrium constant for reaction (1) in the organic solvents is remarkably constant, namely (K) = 0.372 (estimated standard deviation of the mean = 0.014). Thus, the thermodynamics of this reaction in water are substantially different than in the organic solvents studied herein. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Tewari, YB (reprint author), NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 18 TC 12 Z9 12 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1177 J9 J MOL CATAL B-ENZYM JI J. Mol. Catal. B-Enzym. PD MAR 20 PY 2000 VL 9 IS 1-3 BP 83 EP 90 DI 10.1016/S1381-1177(99)00087-9 PG 8 WC Biochemistry & Molecular Biology; Chemistry, Physical SC Biochemistry & Molecular Biology; Chemistry GA 296TR UT WOS:000086042300008 ER PT J AU Troyanchuk, IO Khalyavin, DD Solovykh, TK Szymczak, H Huang, Q Lynn, JW AF Troyanchuk, IO Khalyavin, DD Solovykh, TK Szymczak, H Huang, Q Lynn, JW TI Magnetic and crystal structure phase transitions in R1-xBaxCoO3-y (R = Nd, Gd) SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID TRANSPORT-PROPERTIES; LA1-XSRXCOO3; MAGNETORESISTANCE; BEHAVIOR; STATE AB Perovskites of the R1-xBaxCoO3-y type where R is Nd or Gd have been prepared and characterized. The substitution of Nd by Pa ions up to x = 0.4 leads to a nonhomogeneous ferromagnetic state appearance similar to that found for the La1-xSrxCoO3 system studied earlier. Structural refinement of Nd0.5Ba0.5CoO3-y reveals the chemical ordering of Nd and Pa ions. The magnetic properties of Nd0.5Ba0.5CoO3-y depend drastically on oxygen content Reduced samples (y > 0.2) exhibit magnetic phase transitions at around T-i similar to 200 K and T-C approximate to 280 K as well as a crystal structure transition at T-M approximate to 350 K which leads to a drop in the electrical conductivity. The transitions at T-i and T-M are more pronounced in the Gd1-xBaxCoO3-y series. The decrease of Pa content below x = 0.5 leads to decreasing T-i whereas the increase of Ba ions above x = 0.5 leads to a suppression of both spontaneous magnetization and phase transition at T-M. It is supposed that the transition at T-M results from the oxygen vacancy ordering whereas at T-i the antiferromagnetic state (low temperature phase) transforms into a weak ferromagnetic one with spontaneous magnetization around 0.2 mu(B) per cobalt ion. C1 Byelarussian Acad Sci, Inst Solid State Phys & Semicond, Minsk 220072, Byelarus. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Troyanchuk, IO (reprint author), Byelarussian Acad Sci, Inst Solid State Phys & Semicond, P Brovki St 17, Minsk 220072, Byelarus. RI Khalyavin, Dmitry/E-4335-2017 OI Khalyavin, Dmitry/0000-0002-6724-7695 NR 16 TC 19 Z9 20 U1 1 U2 9 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 MAR 20 PY 2000 VL 12 IS 11 BP 2485 EP 2493 DI 10.1088/0953-8984/12/11/314 PG 9 WC Physics, Condensed Matter SC Physics GA 298NT UT WOS:000086146600015 ER PT J AU Galanter, M Levy, H Carmichael, GR AF Galanter, M Levy, H Carmichael, GR TI Impacts of biomass burning on tropospheric CO, NOx, and O-3 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OZONE MAPPING SPECTROMETER; CARBON-MONOXIDE; SEASONAL-VARIATION; COLUMN OZONE; GLOBAL MODEL; DRY SEASON; VEGETATION; ATMOSPHERE; EMISSIONS; CHEMISTRY AB This study utilizes the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory three-dimensional global chemical transport model to quantify the impacts of biomass burning on tropospheric concentrations of carbon monoxide (CO), nitrogen oxides (NOx), and ozone (O-3). We construct updated global sources that emit 748 Tg CO/yr and 7.8 Tg N/yr in the surface layer. Both sources include six types of biomass: forest, savanna, fuelwood, agricultural residues, domestic crop residues (burned in the home for cooking and/or heating), and dried animal waste. Timing for the burning of forest, savanna, and agricultural residues is based upon regional cultural use of fire, vegetation type, local climate, and information gathered from satellite observations, while emissions from the burning of fuelwood, domestic crop residues, and dried animal waste are constant throughout the year. Based on agreement with observations, particularly of CO, we conclude that the collective uncertainty in our biomass burning sources is much less than the factor of two suggested by previous estimates of biomass burned in the tropics annually. Overall, biomass burning is a major source of CO and NOx in the northern high latitudes during the summer and fall and in the tropics throughout most of the year. While it contributes more than 50% of both the NOx and CO in the boundary layer over major source regions, it has a much larger global impact on the CO-distribution in comparison to either NOx or O-3, contributing 15 to 30% of the entire tropospheric CO background. The only significant biomass burning contribution to NOx at 500 mbar, due to the short lifetime of NOx in the lower troposphere, is a plume occurring July through October in the Southern Hemisphere subtropical free troposphere, stretching from South America to the western Pacific. The largest impacts on O-3 are limited to those regions where NOx impacts are large as well. Near the surface, biomass burning indirectly contributes less than half of the total O-3 concentrations over major tropical source regions, up to 15% throughout the year in the tropics, and 10 to 20% throughout the Southern Hemisphere during September through November. At 500 mbar, the largest contribution to O-3 (20 - 30%) is correlated with the NOx plume during July through November. Biomass burning contributes less than 15% of either NOx or O-3 in the upper troposphere. C1 Princeton Univ, Atmospher & Ocean Space Program, Princeton, NJ 08542 USA. Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Galanter, M (reprint author), Princeton Univ, Atmospher & Ocean Space Program, Princeton, NJ 08542 USA. EM mkg@gfdl.gov; hl@gfdl.gov; gcarmich@icaen.uiowa.edu NR 70 TC 156 Z9 158 U1 5 U2 32 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 MAR 16 PY 2000 VL 105 IS D5 BP 6633 EP 6653 DI 10.1029/1999JD901113 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 294KT UT WOS:000085911000003 ER PT J AU Cooter, EJ Schwede, DB AF Cooter, EJ Schwede, DB TI Sensitivity of the National Oceanic and Atmospheric Administration multilayer model to instrument error and parameterization uncertainty SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INFERENTIAL MEASUREMENT TECHNIQUES; GASEOUS DRY DEPOSITION; SATELLITE-OBSERVATIONS; REGIONAL SCALES; SULFUR-DIOXIDE; CONDUCTANCE; FIELD; RATES; AIR; SO2 AB The response of the National Oceanic and Atmospheric Administration multilayer inferential dry deposition velocity model (NOAA-MLM) to error in meteorological inputs and model parameterization is reported. Monte Carlo simulations were performed to assess the uncertainty in NOAA-MLM deposition velocity V-d estimates for ozone (O-3), sulfur dioxide (SO2), and nitric acid (HNO3) associated with measurements of meteorological variables (including temperature, humidity, radiation, wind speed, wind direction, and leaf area index). Summer daylight scenarios for grass, corn, soybean, oak, and pine were considered. Model sensitivity to uncertainty in the leaf area index (LAI), minimum stomatal resistance, and soil moisture parameterizations was explored. For SO2 and HNO3, instrument error associated with the measurement of wind speed and direction resulted in the greatest V-d error. Depending On vegetation type, the most important source of uncertainty due to instrument error for the V-d of O-3 was LAI. Of the model parameterizations studied, accurate estimation of temporal aspects of the annual LAI profile and the characterization of soil moisture supply and demand are most important to model-estimated V-d uncertainty. Considered individually, these factors can result in SO2 and HNO3 V-d estimate uncertainty of +/-25% and O-3 estimate uncertainty greater than 60%. For single plant species settings, reductions in estimate uncertainty should be possible with minor algorithmic modification, inclusion of more species-appropriate LAI profiles, and careful application of remote sensing technology. C1 US EPA, NERL, Res Triangle Pk, NC 27711 USA. NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Silver Spring, MD 20910 USA. RP Cooter, EJ (reprint author), US EPA, NERL, Res Triangle Pk, NC 27711 USA. EM cooterej@hpcc.epa.gov NR 24 TC 23 Z9 23 U1 0 U2 5 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 MAR 16 PY 2000 VL 105 IS D5 BP 6695 EP 6707 DI 10.1029/1999JD901080 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 294KT UT WOS:000085911000007 ER PT J AU Quinn, PK Bates, TS Miller, TL Coffman, DJ Johnson, JE Harris, JM Ogren, JA Forbes, G Anderson, TL Covert, DS Rood, MJ AF Quinn, PK Bates, TS Miller, TL Coffman, DJ Johnson, JE Harris, JM Ogren, JA Forbes, G Anderson, TL Covert, DS Rood, MJ TI Surface submicron aerosol chemical composition: What fraction is not sulfate? SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; CHARACTERIZATION EXPERIMENT ACE-1; CLOUD CONDENSATION NUCLEI; NORTHEAST PACIFIC-OCEAN; LONG-RANGE TRANSPORT; ST-LOUIS REGION; SEA-SALT; OPTICAL-PROPERTIES; SIZE DISTRIBUTION; METEOROLOGICAL TRANSPORT AB Measurements of submicron aerosol mass and the mass of major ionic components have been made over the past 5 years on cruises in the Pacific and Southern Oceans and at monitoring stations across North America (Barrow, Alaska; Cheeka Peak, Washington; Bondville, Illinois; and Sable Island, Nova Scotia). Reported here are submicron concentrations of aerosol mass, nonsea salt (nss) sulfate, sea salt, methanesulfonate, other nss inorganic ions, and residual, or chemically unanalyzed, mass. Residual mass concentrations are based on the difference between simultaneously measured aerosol mass and the mass of the major ionic components. A standardized sampling protocol was used for all measurements making the data from each location directly comparable. For the Pacific and Southern Oceans, concentrations of the chemical components are presented in zonally averaged 200 latitude bins. For the monitoring stations, mean concentrations are presented for distinct air mass types (marine, clean continental, and polluted based on air mass back trajectories). In addition, percentile information for each chemical component is given to indicate the variability in the measured concentrations. Mean nss sulfate submicron aerosol mass fractions for the different latitude bins of the Pacific ranged from 0.14 +/- 0.01 to 0.34 +/- 0.03 (arithmetic mean +/- absolute uncertainty at the 95% confidence level). The lowest average value occurred in the 40 degrees-60 degrees S latitude band where nss sulfate concentrations were low due to the remoteness from continental sources and sea salt concentrations were relatively high. Mean nss sulfate aerosol mass fractions were more variable at the monitoring stations ranging from 0.13 +/- 0.004 to 0.65 +/- 0.02. Highest values occurred in polluted air masses at Bondville and Sable Island. Sea salt mean mass fractions ranged between 0.20 +/- 0.02 and 0.53 +/- 0.03 at all latitude bands of the Pacific (except 20 degrees-40 degrees N where the residual mass fraction was relatively high) and at Barrow. The concentration of residual mass was significant at the 95% confidence level at all stations and all Pacific latitude bands (assuming that all errors were random and normally distributed and contamination of the samples did not occur beyond that accounted for by storage and transport uncertainties). Mean residual mass fractions ranged from 0.09 +/- 0.07 to 0.74 +/- 0.04. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Environm Canada, Sable Isl, NS B2Y 2N6, Canada. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Illinois, Dept Civil & Environm Engn, Urbana, IL 61801 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Quinn, PK (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM quinn@pmel.noaa.gov RI Ogren, John/M-8255-2015; Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Ogren, John/0000-0002-7895-9583; Quinn, Patricia/0000-0003-0337-4895 NR 64 TC 51 Z9 51 U1 1 U2 8 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 MAR 16 PY 2000 VL 105 IS D5 BP 6785 EP 6805 DI 10.1029/1999JD901034 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 294KT UT WOS:000085911000015 ER PT J AU Bergin, MH Schwartz, SE Halthore, RN Ogren, JA Hlavka, DL AF Bergin, MH Schwartz, SE Halthore, RN Ogren, JA Hlavka, DL TI Comparison of aerosol optical depth inferred from surface measurements with that determined by Sun photometry for cloud-free conditions at a continental US site SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RAMAN LIDAR MEASUREMENTS; ANTHROPOGENIC AEROSOLS; HYGROSCOPIC GROWTH; AMMONIUM-NITRATE; LIGHT-SCATTERING; BOUNDARY-LAYER; CLIMATE; EXTINCTION; BACKSCATTERING; APPORTIONMENT AB Evaluation of the forcing of climate by aerosol scattering of shortwave radiation in cloud-free conditions(direct aerosol forcing) requires knowledge of aerosol optical properties on relevant spatial and temporal scales. It is convenient to measure these properties at the surface. However, before these measurements can be used to quantitatively estimate direct climate forcing, it is necessary to determine the extent to which these properties are representative of the entire atmospheric column. In this paper we compare aerosol optical depth (AOD) determined by Sun photometry at the Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site in north central Oklahoma for several cloud-free days with estimates of AOD based on two methods. First, the aerosol extinction measured at the surface (taken as the sum of the aerosol scattering and absorption coefficients at instrumental relative humidity of similar to 20%) is multiplied by the mixing height determined from temperature profiles from radiosonde measurements. Even under conditions of vigorous midday mixing this approach underestimates AOD by as much as 70% using dry aerosol measurements and by roughly 40% when hygroscopic growth of aerosol under ambient relative humidity is taken into account. This discrepancy is attributed primarily to underestimation of aerosol column extinction, as confirmed by examination of normalized aerosol backscatter profiles obtained from micropulse lidar (MPL), which show substantial contributions of aerosol loading above the atmospheric boundary layer. The second approach uses MPL profiles of normalized aerosol backscatter to estimate the vertical profile of aerosol extinction using surface values. The resulting AOD's are on average 30% less than measured values. This discrepancy is attributed to hygroscopic growth of aerosols in the atmospheric column. The results show that at the SGP site even under conditions of vigorous mixing in the atmospheric boundary layer the aerosol optical depth cannot be estimated with surface measurements of aerosol extinction unless information on the vertical profile of aerosol extinction is taken into account. C1 Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Div, Greenbelt, MD 20771 USA. RP Bergin, MH (reprint author), Georgia Inst Technol, Sch Civil & Environm Engn, Atlanta, GA 30332 USA. EM mike.bergin@ce.gatech.edu RI Schwartz, Stephen/C-2729-2008; Ogren, John/M-8255-2015 OI Schwartz, Stephen/0000-0001-6288-310X; Ogren, John/0000-0002-7895-9583 NR 37 TC 30 Z9 31 U1 0 U2 3 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 MAR 16 PY 2000 VL 105 IS D5 BP 6807 EP 6816 DI 10.1029/1999JD900454 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 294KT UT WOS:000085911000016 ER PT J AU Hall, A Manabe, S AF Hall, A Manabe, S TI Effect of water vapor feedback on internal and anthropogenic variations of the global hydrologic cycle SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; CLIMATE; CO2; OCEAN AB Using two versions of the GFDL coupled ocean-atmosphere model, one where water vapor anomalies are allowed to affect the longwave radiation calculation and one where they are not, we examine the role of water vapor feedback in internal precipitation variability and greenhouse-gas-forced intensification of the hydrologic cycle. Without external forcing, the experiment with water vapor feedback produces 44% more annual-mean, global-mean precipitation variability than the one without. We diagnose the reason for this difference: In both experiments, global-mean surface temperature anomalies are associated with water vapor anomalies. However, when water vapor interacts with longwave radiation,the temperature anomalies are associated with larger anomalies in surface downward longwave radiation. This increases the temperature anomaly damping through latent heat flux, creating an evaporation anomaly. The evaporation anomaly, in turn, leads to an anomaly of nearly the same magnitude in precipitation. In the experiment without water vapor feedback, this mechanism is absent. While the interaction between longwave and water vapor has a large impact on the global hydrologic cycle internal variations, its effect decreases as spatial scales decrease, so water vapor feedback has only a very small impact on grid-scale hydrologic variability. Water vapor feedback also affects the hydrologic cycle intensification when greenhouse gas concentrations increase. By the 5th century of global warming experiments where CO2 is increased and then fixed at its doubled value, the global-mean precipitation increase is nearly an order of magnitude larger when water vapor feedback is present. The cause of this difference is similar to the cause of the difference in internal precipitation variability: When water vapor feedback is present, the increase in water vapor associated with a warmer climate enhances downward longwave radiation. To maintain surface heat balance, evaporation increases, leading to a similar increase in precipitation. This effect is absent in the experiment without water vapor feedback. The large impact of water vapor feedback on hydrologic cycle intensification does not weaken as spatial scales decrease, unlike the internal variability case. Accurate representations of water vapor feedback are therefore necessary to simulate global-scale hydrologic variability and intensification of the hydrologic cycle in global warming. C1 Inst Global Change Res, FRSGC, Tokyo 1056791, Japan. Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RP Hall, A (reprint author), Columbia Univ, Lamont Doherty Geol Observ, Oceanog Bldg,Room 103,POB 1000,61 Route 9W, Palisades, NY 10964 USA. EM alexhall@rosie.ldeo.columbia.edu RI Hall, Alex/D-8175-2014 NR 16 TC 15 Z9 15 U1 0 U2 12 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 MAR 16 PY 2000 VL 105 IS D5 BP 6935 EP 6944 DI 10.1029/1999JD901172 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 294KT UT WOS:000085911000027 ER PT J AU Orlando, JJ Burkholder, JB AF Orlando, JJ Burkholder, JB TI Identification of BrONO as the major product in the gas-phase reaction of Br with NO2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID THERMAL UNIMOLECULAR REACTIONS; NITRYL BROMIDE; TRANS-BRONO; MATRIX REACTIONS; CHLORINE ATOMS; RATE CONSTANTS; LOW-PRESSURES; NU(4) BAND; CIS-BRONO; BRNO2 AB Products of the gas-phase reaction of Br atoms with NO2 have been quantitatively determined at temperatures between 215 and 300 K in an environmental chamber interfaced to an FT-IR spectrometer. The major product of the reaction (yield > 75%) was found to be the cis isomer of BrONO, which was identified and quantified by means of its N=O stretching fundamental at 1660 cm-(1); this represents the first gas-phase detection of this species. Although rapid thermal decomposition back to Br and NO2 precludes its detection at room temperature (lifetime < 1 s), BrONO was detected at temperatures at and below 263 K. Isomerization of the BrONO to BrNO2 was found to be an important fate of BrONO at low temperatures. The rate coefficient for this process was found to increase with decreasing pressure, indicative of a heterogeneous process. At 700 Torr, this isomerization rate was (0.013 +/- 0.003) s(-1), independent of temperature over the range 218-243 K. Evidence was also obtained for rapid reactions between Br atoms and both BrONO and BrNO2 (10(-10) > k > 10(-11) cm(3) molecule(-1) s(-1)). C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Orlando, JJ (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013 NR 36 TC 17 Z9 17 U1 0 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 MAR 16 PY 2000 VL 104 IS 10 BP 2048 EP 2053 DI 10.1021/jp993713g PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 294GD UT WOS:000085902700012 ER PT J AU Sackett, CA Kielpinski, D King, BE Langer, C Meyer, V Myatt, CJ Rowe, M Turchette, QA Itano, WM Wineland, DJ Monroe, C AF Sackett, CA Kielpinski, D King, BE Langer, C Meyer, V Myatt, CJ Rowe, M Turchette, QA Itano, WM Wineland, DJ Monroe, C TI Experimental entanglement of four particles SO NATURE LA English DT Article ID COLD TRAPPED IONS; QUANTUM; GENERATION; STATES; PAIRS AB Quantum mechanics allows for many-particle wavefunctions that cannot be factorized into a product of single-particle wavefunctions, even when the constituent particles are entirely distinct Such 'entangled' states explicitly demonstrate the non-local character of quantum theory(1), having potential applications in high-precision spectroscopy(2), quantum communication, cryptography and computation(3). In general, the more particles that can be entangled, the more dearly nonclassical effects are exhibited(4,5)-and the more useful the states are for quantum applications. Here we implement a recently proposed entanglement technique(6) to generate entangled states of two and four trapped ions. Coupling between the ions is provided through their collective motional degrees of freedom, but actual motional excitation is minimized. Entanglement is achieved using a single laser pulse, and the method can in principle be applied to any number of ions. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. NIST, Atom Phys Div, Gaithersburg, MD 20899 USA. Res Electroopt, Boulder, CO 80301 USA. RP Monroe, C (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. EM monroe@boulder.nist.gov RI Monroe, Christopher/G-8105-2011; OI Kielpinski, David/0000-0002-2816-6892 NR 30 TC 970 Z9 992 U1 10 U2 68 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAR 16 PY 2000 VL 404 IS 6775 BP 256 EP 259 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 296JX UT WOS:000086022200039 ER PT J AU Nash, CE Iwamoto, RN Mahnken, CVW AF Nash, CE Iwamoto, RN Mahnken, CVW TI Aquaculture risk management and marine mammal interactions in the Pacific Northwest SO AQUACULTURE LA English DT Article DE aquatic farming; marine mammals; Pacific coast ID PREDATION; SALMON AB This paper reviews current aquatic farm production in the USA and estimates an annual financial exposure of US$350 million in the marine and coastal environments made up of sales, standing crop value and capital investment. In addition, nationwide aquatic fanning creates almost 200,000 jobs and, with secondary and downstream activities combined, contributes about US$5600 million to the GNP. The paper then reviews the increasing risk that elements of the coastal aquaculture industry in the Pacific Northwest face from interactions with populations of marine mammals. These are particularly California sea lions and seals, which have greatly increased in the last 20 years from California to British Columbia. Specifically: (i) shellfish from traditional beds have been contaminated by fecal coliforms from seals and made unfit for human consumption, and have been experiencing increasing losses to river otters and sea otters; (ii) culture-based salmon fisheries, including endangered salmon stocks, have been exposed to heavy predation by sea lions and seals, resulting in both direct losses and reduced market value of wounded survivors; (iii) net-pen farms have been exposed to the same heavy losses from predatory sea lions and seals attacking fish in the pens, together with added financial burdens for anti-predator nets, increased maintenance and labor; and (iv) workers in aquaculture and fisheries, and other waterborne industries, have been observing less fear of humans by sea lions and seals, and more direct damage to servicing facilities. The four issues are discussed both technically and economically, and a number of solutions proposed for managing and controlling these increasing risks. (C) 2000 Published by Elsevier Science B.V. C1 Natl Marine Fisheries Serv, NOAA, NW Fisheries Sci Ctr, Resource Enhancement & Utilizat Technol Div, Seattle, WA 98112 USA. RP Nash, CE (reprint author), NMFS, Manchester Marine Expt Stn, POB 130, Manchester, WA 98353 USA. NR 29 TC 29 Z9 31 U1 1 U2 28 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD MAR 15 PY 2000 VL 183 IS 3-4 BP 307 EP 323 DI 10.1016/S0044-8486(99)00300-2 PG 17 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 286CU UT WOS:000085426700010 ER PT J AU Levenson, DH Dizon, A Ponganis, PJ AF Levenson, DH Dizon, A Ponganis, PJ TI Identification of loss-of-function mutations within the short-wavelength sensitive cone opsin genes of baleen and odontocete cetaceans. SO INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE LA English DT Meeting Abstract C1 Scripps Inst Oceanog, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Natl Marine Fisheries Serv, La Jolla, CA USA. NR 0 TC 4 Z9 4 U1 0 U2 0 PU ASSOC RESEARCH VISION OPHTHALMOLOGY INC PI ROCKVILLE PA 12300 TWINBROOK PARKWAY, ROCKVILLE, MD 20852-1606 USA SN 0146-0404 EI 1552-5783 J9 INVEST OPHTH VIS SCI JI Invest. Ophthalmol. Vis. Sci. PD MAR 15 PY 2000 VL 41 IS 4 SU S MA 3240B338 BP S610 EP S610 PG 1 WC Ophthalmology SC Ophthalmology GA 300HF UT WOS:000086246703310 ER PT J AU Ogi, H Dunn, ML Takashima, K Ledbetter, H AF Ogi, H Dunn, ML Takashima, K Ledbetter, H TI Elastic properties of a unidirectional SiCf/Ti composite: Acoustic-resonance measurements and micromechanics predictions SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MATRIX; SPECTROSCOPY; STRESS AB Using the mode-selective contactless resonance ultrasound spectroscopy, we measured the complete elastic-stiffness tensor C-ij and the corresponding internal-friction tensor Q(ij)(-1) of a silicon-carbide fiber unidirectionally reinforced Ti-6Al-4V-matrix composite. This material shows orthorhombic symmetry and possesses nine independent C-ij and Q(ij)(-1). We independently excited and detected an unique vibration-mode group among the eight vibration groups of a orthorhombic rectangular parallelepiped. This provides a great advantage in identifying the vibration modes of the observed resonance peaks, whose frequencies yield the C-ij by solving an inverse problem. To verify the resultant C-ij, we also determined C-ij by point-contact resonance ultrasound spectroscopy and pulse-echo methods. Then, using the composite C-ij, we inversely calculated the transverse-isotropic fiber elastic stiffnesses with micromechanics theory. With the fiber C-ij and the isotropic matrix C-ij, we reconstructed the composite C-ij as a function of fiber-volume fraction. (C) 2000 American Institute of Physics. [S0021-8979(00)07206-6]. C1 Osaka Univ, Grad Sch Engn Sci, Osaka 5608531, Japan. Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. Tokyo Inst Technol, Precis & Intelligence Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Ogi, H (reprint author), Osaka Univ, Grad Sch Engn Sci, Machikaneyama 1-3, Osaka 5608531, Japan. OI DUNN, MARTIN/0000-0002-4531-9176 NR 20 TC 12 Z9 12 U1 0 U2 1 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 MAR 15 PY 2000 VL 87 IS 6 BP 2769 EP 2774 DI 10.1063/1.372254 PG 6 WC Physics, Applied SC Physics GA 287WY UT WOS:000085531400015 ER PT J AU Parks, DC Chen, PJ Egelhoff, WF Gomez, RD AF Parks, DC Chen, PJ Egelhoff, WF Gomez, RD TI Interfacial roughness effects on interlayer coupling in spin valves grown on different seed layers SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID SURFACE-ROUGHNESS; MAGNETORESISTANCE; MULTILAYERS AB We have studied the behavior of interlayer coupling in giant magnetoresistance spin valves as a function of seed layer composition and spacer layer thickness. Using in situ scanning tunneling microscopy, we have measured directly the roughness of the top surface of the lower ferromagnetic layer. We find that the seed layer composition is correlated to the roughnesses of the interfaces inside the spin valve. Interlayer coupling increases with decreasing Cu spacer layer thickness and with increasing interfacial roughness. Results favorably compare to a topographically derived magnetostatic interaction as described by a modified version of Neel's "orange peel" model. (C) 2000 American Institute of Physics. [S0021-8979(00)05506-7]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Parks, DC (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 12 TC 23 Z9 23 U1 0 U2 2 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 MAR 15 PY 2000 VL 87 IS 6 BP 3023 EP 3026 DI 10.1063/1.372390 PG 4 WC Physics, Applied SC Physics GA 287WY UT WOS:000085531400055 ER PT J AU Schwartz, RL Davico, GE Kim, JB Lineberger, CW AF Schwartz, RL Davico, GE Kim, JB Lineberger, CW TI Negative ion photoelectron spectroscopy of OH-(NH3) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HYDROGEN ABSTRACTION REACTIONS; TRANSITION-STATE SPECTROSCOPY; THRESHOLD PHOTODETACHMENT; NH3+OH->NH2+H2O REACTION; RATE CONSTANTS; OH; DYNAMICS; COMPLEXES; OD AB The 351 nm photoelectron spectra of OH-(NH3)(n) n=1,2 and the deuterated analogs exhibit two broad peaks. Ab initio calculations of the anion and neutral potential-energy surfaces have been carried out using an MP2 (second-order Moller-Plesset)/6-31++G(**) basis set. The geometries, frequencies, and energetics from these calculations aid in the interpretation of the experimental results. An estimate of the OH(NH3) electron affinity is 2.35 +/- 0.07 eV based on experimental and theoretical results. Calculations of the anion vibrational wave functions indicate that following electron photodetachment, the neutral potential-energy surface is accessed from the reactant entrance channel through the transition state region. (C) 2000 American Institute of Physics. [S0021-9606(00)00711-X]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. EM wcl@jila.colorado.edu NR 26 TC 7 Z9 7 U1 1 U2 6 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 MAR 15 PY 2000 VL 112 IS 11 BP 4966 EP 4973 DI 10.1063/1.481051 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 290QT UT WOS:000085687900008 ER PT J AU Trokhimovski, YG Irisov, VG Westwater, ER Fedor, LS Leuski, VE AF Trokhimovski, YG Irisov, VG Westwater, ER Fedor, LS Leuski, VE TI Microwave polarimetric measurements of the sea surface brightness temperature from a blimp during the Coastal Ocean Probing Experiment (COPE) SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WIND-GENERATED WAVES; IMPROVED MODEL; WATER-VAPOR; RADIOMETER; SLOPE; BACKSCATTERING; PERMITTIVITY; FREQUENCIES; SCATTERING; DEPENDENCE AB Experimental data obtained with a microwave dual-frequency radiometer at 23.87 and 31.65 GHz and a polarimeter at 37.0 GHz installed on a blimp during the Coastal Ocean Probing Experiment in 1995 are analyzed. Observations of the downwelling atmospheric radiation as a function of angle were used to achieve a highly accurate absolute calibration. The dependence of the sea surface brightness temperature on nadir and azimuthal angles is considered. The experimental data are compared with theoretical calculations based on several models of sea wave spectra. Models proposed by Romeiser et al. [1997] and Elfouhaily et al. [1997] fit well to the COPE azimuthal measurements and data averaged over azimuthal angle are in between of values predicted by spectrum models by Apel [1994] and Elfouhaily et al. [1997]. The conclusion is made about high sensitivity of the polarized radiometric measurements to parameters of gravity-capillary spectrum. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Trokhimovski, YG (reprint author), NOAA, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. EM virisov@etl.noaa.gov NR 49 TC 9 Z9 12 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 2000 VL 105 IS C3 BP 6501 EP 6516 DI 10.1029/1999JC900315 PG 16 WC Oceanography SC Oceanography GA 293YG UT WOS:000085882400014 ER PT J AU Lou, J Schwab, DJ Beletsky, D Hawley, N AF Lou, J Schwab, DJ Beletsky, D Hawley, N TI A model of sediment resuspension and transport dynamics in southern Lake Michigan SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID DEPTH-INTEGRATED MODEL; FINE-GRAINED SEDIMENTS; WAVE PREDICTION MODEL; SUSPENDED SEDIMENT; NUMERICAL-SIMULATION; CIRCULATION; BOTTOM; ENTRAINMENT; CURRENTS; DRIVEN AB A quasi-three-dimensional suspended sediment transport model was developed and generalized to include combined wave-current effects to study bottom sediment resuspension and transport in southern Lake Michigan. The results from a three-dimensional circulation model and a wind wave model were used as input to the sediment transport model. Two effects of nonlinear wave-current interactions were considered in the sediment transport model: the changes in turbulence intensity due to waves and the enhancement of induced bottom shear stresses. Empirical formulations of sediment entrainment and resuspension processes were established and parameterized by laboratory data and field studies in the lake. In this preliminary application of the model to Lake Michigan, only a single grain size is used to characterize the sedimentary material, and the bottom of the lake is treated as an unlimited sediment source. The model results were compared with measured suspended sediment concentrations at two stations and several municipal water intake turbidity measurements in southern Lake Michigan during November-December 1994. The model was able to reproduce the general patterns of high-turbidity events in the lake. A model simulation for the entire 1994-1995 two-year period gave a reasonable description of sediment erosion/deposition in the lake, and the modeled settling mass fluxes were consistent with sediment trap data. The mechanisms of sediment resuspension and transport in southern Lake Michigan are discussed. To improve the model, sediment classifications, spatial bottom sediment distribution, sediment source function, and tributary sediment discharge should be considered. C1 NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. Univ Michigan, Dept Naval Architecture & Marine Engn, Ann Arbor, MI USA. RP Lou, J (reprint author), NOAA, Great Lakes Environm Res Lab, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. EM lou@glerl.noaa.gov; schwab@glerl.noaa.gov; beletsky@glerl.noaa.gov RI Schwab, David/B-7498-2012; OI Beletsky, Dmitry/0000-0003-4532-0588 NR 72 TC 51 Z9 55 U1 2 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 15 PY 2000 VL 105 IS C3 BP 6591 EP 6610 DI 10.1029/1999JC900325 PG 20 WC Oceanography SC Oceanography GA 293YG UT WOS:000085882400021 ER PT J AU Xu, Q Gu, W AF Xu, Q Gu, W TI Baroclinic Eady wave and fronts. Part II: Geostrophic potential vorticity dynamics in semigeostrophic space SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ACTIVITY CONSERVATION-LAWS; ELECTROSTATICS ANALOGY; STABILITY THEOREMS; SINGULAR VECTORS; MODEL; FORMULATION; EQUATIONS AB The geostrophic coordinate transformation is applied to the viscous semigeostrophic (SG) Eady wave. In the transformed space, called the SG space, the potential temperature anomaly can be treated as a delta-function anomaly of geostrophic potential vorticity (GPV) at the physical boundary or imaginary boundary (along the top of the boundary layer). Since the delta-function anomaly is analogous to the surface charge of a problem in electrostatics with the induced geopotential playing the role of the electric potential, the development of the Eady wave and fronts can be interpreted in terms of the interaction between the "surface charges" at two imaginary boundaries. It is shown that this interpretation and related GPV thinking for the viscous SG Eady wave can be made nearly as concise as its inviscid paradigm during the boundary stage (until the inviscid surface front collapses in physical space). When the viscous SG Eady wave develops into the interior stage, strong interior GPV anomalies, analogous to "body charges," are generated by the diffusive GPV flux. These body charges form two domes in the SG space. The geostrophic flow field induced by the body charge in each dome produces diffusive GPV fluxes that converge at the upstream edge of each dome and thus keep the body charge in step against the horizontal advection. The growth of the geometric area of each dome of body charge (or the penetration of the front into the interior in physical space), however, is caused mainly by the ageostrophic circulation forced by the geostrophic flow. It is also shown that the body charge in each dome can be represented by the surface charge (potential temperature anomaly) on an imaginary boundary that covers the dome (above the boundary layer). The growth of these surface charges can be explained by a simplified GPV thinking applied only to the nearly inviscid interior region, similar to its inviscid counterpart for the interior stage (beyond the time that the inviscid surface front collapses in physical space). C1 USN, Res Lab, Monterey, CA USA. Univ Oklahoma, CIMMS, Norman, OK 73019 USA. RP Xu, Q (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 22 TC 7 Z9 7 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 15 PY 2000 VL 57 IS 6 BP 861 EP 872 DI 10.1175/1520-0469(2000)057<0861:BEWAFP>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 291FR UT WOS:000085723900005 ER PT J AU Paek, EG Im, YS Choe, JY Oh, TK AF Paek, EG Im, YS Choe, JY Oh, TK TI Acoustically steered and rotated true-time-delay generator based on wavelength-division multiplexing SO APPLIED OPTICS LA English DT Article ID PHASED-ARRAY ANTENNAS; PROGRAMMABLE DISPERSION MATRIX; FIBEROPTIC CONTROL; TRANSMITTER; PRISM; LINE AB The acoustically steered and rotated (ASTRO) true-time-delay (TTD) generator, capable of two-dimensional (2D) multiple beam generation without causing extraneous beams, is described. It is based on wavelength-division multiplexing to encode and decode various;linear chirp time delays with wavelengths. An array of equally spaced Light stripes with Linear chirp time delays among them is formed and is subsequently rotated to a desired angle by use of our nonmechanical acousto-optic dove prism, believed to be novel. Our architecture reduces hardware complexity significantly by avoiding redundancy in conventional TTD generators. Experimental results to prove the concept of 2D multiple beam generation are shown. Also, an extension of the system for bidirectional communications is proposed. Various technical issues for practical applications:are discussed. C1 Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. USN, Res Lab, Div Radar, Washington, DC 20375 USA. USN, Ctr Surface Warfare, Dahlgren, VA 22448 USA. RP Paek, EG (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. EM paek@nist.gov NR 23 TC 6 Z9 6 U1 0 U2 0 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 MAR 10 PY 2000 VL 39 IS 8 BP 1298 EP 1308 DI 10.1364/AO.39.001298 PG 11 WC Optics SC Optics GA 292BV UT WOS:000085775000010 PM 18338014 ER PT J AU Kling, R Griesmann, U AF Kling, R Griesmann, U TI Accurate f-values for ultraviolet transitions from the 3d(5)(S-6)4p levels in MnII SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; methods : laboratory ID HOLLOW-CATHODE AB We have measured branching fractions for ultraviolet electric dipole transitions from upper levels belonging to the 3d(5)(S-6)4p P-7 and 3d(5)(S-6)4p P-5 terms of Mn II. The levels were excited in a hollow cathode lamp and the spectra were observed with a Fourier transform spectrometer. The high signal-to-noise ratio of the Mn II lines in our spectra permitted the measurement of branching fractions even for the weakest transitions in the ultraviolet, which are of particular astrophysical interest. A comparison with previous measurements revealed that many of these measurements, including the most recent, show systematic distortions that may indicate that they are affected by self-absorption. Absolute oscillator strengths, based on the new branching fraction measurements, were determined using existing experimental lifetime data. The uncertainty of the f-values is less than 5% for strong transitions. Oscillator strengths for several very weak intercombination lines with log gf < -2 are reported for the first time. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Kling, R (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 24 TC 29 Z9 29 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2000 VL 531 IS 2 BP 1173 EP 1178 DI 10.1086/308490 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 299MA UT WOS:000086201300053 ER PT J AU D'Sa, EJ Zaitzeff, JB Steward, RG AF D'Sa, EJ Zaitzeff, JB Steward, RG TI Monitoring mater quality in Florida Bay with remotely sensed salinity and in situ bio-optical observations SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID CHLOROPHYLL AB Water quality variables were examined in Florida Bay, an ecologically sensitive ecosystem, in a pilot monitoring effort using remotely sensed sea surface salinity and in situ bio-optical observations. An airborne scanning low frequency microwave radiometer provided the first fine spatial resolution description of the surface salinity held in Florida Bay, USA. Low salinity levels to the north and central region of the Bay indicated freshwater inflows from the Everglades, while marine conditions influenced by the Gulf of Mexico waters prevailed in the western (outer) region of the Bay. Bio-optical variables such as chlorophyll a, suspended solids, coloured dissolved organic matter(yellow substance) and remote sensing reflectance exhibited different distribution patterns in the low and high salinity regions of the Bay. The results demonstrate the importance of salinity measurements in delineating diverse bio-optical regimes to aid the development of regional ocean colour remote sensing algorithms for coastal waters. C1 Natl Ocean & Atmospher Adm, NESDIS, Off Res & Appl, Suitland, MD 20746 USA. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. RP D'Sa, EJ (reprint author), Natl Ocean & Atmospher Adm, NESDIS, Off Res & Appl, 5200 Auth Rd, Suitland, MD 20746 USA. NR 11 TC 11 Z9 13 U1 0 U2 8 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD MAR 10 PY 2000 VL 21 IS 4 BP 811 EP 816 DI 10.1080/014311600210605 PG 6 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 285LH UT WOS:000085390200015 ER PT J AU Slusher, JT AF Slusher, JT TI Shear viscosity and dielectric constant in aqueous isopropanol aqueous acetonitrile SO MOLECULAR PHYSICS LA English DT Article ID MOLECULAR-DYNAMICS SIMULATIONS; VAPOR-LIQUID-EQUILIBRIUM; WATER-METHANOL MIXTURES; COMPUTER-SIMULATION; FREE-ENERGY; HYDROPHOBIC HYDRATION; ALCOHOL MIXTURES; PHASE-EQUILIBRIA; SYSTEMS; SOLVATION AB The importance of aqueous mixtures as solvents has motivated the investigation of the usefulness of classical molecular dynamics simulation, using simple effective pair potentials and the Lorentz-Berthelot combining rules, to predict mixture viscosities and dielectric constants. In the acetonitrile-water system, near quantitative agreement with experiment is found; however, the calculated shear viscosity in the 2-propanol-water system is underpredicted by more than a factor of two. Moreover, the results do not appear to be strongly dependent on the mixture combining rules, as a 10% decrease in the unlike OO Lennard-Jones size parameter for this system had no discernable effect on the calculated viscosity. In both systems, the dielectric constant predictions were in qualitative accord with experiment, although systematically underpredicted as in the pure component models. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Slusher, JT (reprint author), Lockheed Martin Corp, 3201 Jermantown Rd, Fairfax, VA 22030 USA. NR 62 TC 12 Z9 12 U1 0 U2 11 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD MAR 10 PY 2000 VL 98 IS 5 BP 287 EP 293 DI 10.1080/002689700162568 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 287CB UT WOS:000085486200003 ER PT J AU Grodkowski, J Neta, P AF Grodkowski, J Neta, P TI Cobalt corrin catalyzed photoreduction of CO2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-METAL COMPLEXES; CARBON-DIOXIDE; PHOTOCHEMICAL REDUCTION; VITAMIN-B12; DERIVATIVES AB Cobalt corrins (B-12) are found to act as homogeneous catalysts for photoreduction of CO2 to CO and formic acid Photoreduction is carried out in acetonitrile/methanol solutions containing p-terphenyl as a photosensitizer and triethylamine as a reductive quencher. Photolysis (lambda greater than or equal to 300 nm) leads to production of CO and formic acid as well as H-2. The rate of production of all three products is considerably higher with the corrins (hydroxocobalamin, cyanocobalamin, and cobinamide) than with cobalt tetra-m-tolylporphyrin. The mechanism of CO2 reduction in all cases is via a species formed by one-electron reduction of the Co(I) complex. Radiolytic studies of the Co(I) complex formed from hydroxocobalamin in aqueous solutions show that this compound reacts very rapidly with solvated electrons and more slowly [k = (1.2 +/- 0.3) x 10(8) L mol(-1) s(-1)] with CO2.- radicals to produce different products. The initial reduction product is suggested to be mainly the hydride formed by protonation of a Co(0) corrin, (HCoB12)(-). The product of reaction with CO2.- is suggested to be the adduct (CO2CoB12)(2-) or its protonated form (HO2CCoB12)(-), identical to the adduct formed by reaction of CO2 with the photochemically reduced Co(I) corrin, which proceeds to produce CO. H-2 is formed by reaction of the hydride with a proton. Side reactions leading to hydrogenation of the macrocycle also take place and limit the catalytic activity. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Neta, P (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 24 TC 27 Z9 27 U1 1 U2 24 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 9 PY 2000 VL 104 IS 9 BP 1848 EP 1853 DI 10.1021/jp9939569 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 291ZV UT WOS:000085770400010 ER PT J AU Genzer, J Sivaniah, E Kramer, EJ Wang, JG Korner, H Xiang, ML Char, K Ober, CK DeKoven, BM Bubeck, RA Chaudhury, MK Sambasivan, S Fischer, DA AF Genzer, J Sivaniah, E Kramer, EJ Wang, JG Korner, H Xiang, ML Char, K Ober, CK DeKoven, BM Bubeck, RA Chaudhury, MK Sambasivan, S Fischer, DA TI The orientation of semifluorinated alkanes attached to polymers at the surface of polymer films SO MACROMOLECULES LA English DT Article ID BLOCK-COPOLYMERS; MONOLAYERS; NEXAFS AB The surface molecular orientation of a liquid crystalline (LC) layer made up of semifluorinated (SF) single side groups [-CO-(CH2)(x-1)-(CF2)(y)F] (single SF groups) attached to polyisoprene homopolymer or the isoprene block of a styrene-isoprene diblock copolymer was determined by analyzing the partial electron yield C-edge NEXAFS signal. The results show that the surfaces of thin SF polymer films are covered with a uniform layer, consisting of the SF-LC groups whose average -CF2- tilt angle with the surface normal lies in the range 29-46 degrees. This is in direct contrast to the bulk, where the directors of the SF-LC mesogens are aligned parallel to the polystyrene/SF-polyisoprene interface of the block copolymers. This average tilt angle increases with increasing the length of the -(CH2)(x-1)- group (x increases) but decreases with increasing the length of the -(CF2)(y)- part of the molecule (y increases) at constant x. C1 N Carolina State Univ, Dept Chem Engn, Raleigh, NC 27695 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. Cornell Univ, Dept Mat Sci & Engn, Ithaca, NY 14853 USA. Intevac, Santa Clara, CA 95054 USA. RAB Consulting, Midland, MI 48640 USA. Lehigh Univ, Dept Chem Engn, Bethlehem, PA 18015 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Char, K (reprint author), N Carolina State Univ, Dept Chem Engn, Raleigh, NC 27695 USA. NR 16 TC 102 Z9 104 U1 0 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAR 7 PY 2000 VL 33 IS 5 BP 1882 EP 1887 DI 10.1021/ma991182o PG 6 WC Polymer Science SC Polymer Science GA 293BY UT WOS:000085832700065 ER PT J AU Herman, M AF Herman, M TI Pervasive computing/smart spaces pose a host of challenges SO ELECTRONIC DESIGN LA English DT Editorial Material C1 NIST, Informat Technol Lab, Informat Access & User Interfaces Div, Gaithersburg, MD 20899 USA. RP Herman, M (reprint author), NIST, Informat Technol Lab, Informat Access & User Interfaces Div, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PENTON MEDIA, INC PI CLEVELAND PA 1100 SUPERIOR AVE, CLEVELAND, OH 44114-2543 USA SN 0013-4872 J9 ELECTRON DES JI Electron. Des. PD MAR 6 PY 2000 VL 48 IS 5 BP 52 EP 52 PG 1 WC Engineering, Electrical & Electronic SC Engineering GA 292ER UT WOS:000085781600012 ER PT J AU Rosenberg, AM AF Rosenberg, AM TI Investigation of chloride diffusion for high-performance concrete containing fly ash, microsilica, and chemical admixtures. Paper by Zongjin Li, Jun Peng, and Baoguo Ma - Discussion SO ACI MATERIALS JOURNAL LA English DT Editorial Material C1 Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. RP Rosenberg, AM (reprint author), Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER CONCRETE INST PI FARMINGTON HILLS PA 38800 INTERNATIONAL WAY, COUNTRY CLUB DRIVE, PO BOX 9094, FARMINGTON HILLS, MI 48333-9094 USA SN 0889-325X J9 ACI MATER J JI ACI Mater. J. PD MAR-APR PY 2000 VL 97 IS 2 BP 234 EP 234 PG 1 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 304EC UT WOS:000086469000019 ER PT J AU Ostashev, VE Wilson, DK AF Ostashev, VE Wilson, DK TI Relative contributions from temperature and wind velocity fluctuations to the statistical moments of a sound field in a turbulent atmosphere SO ACUSTICA LA English DT Article ID SURFACE-LAYER; PROPAGATION; INHOMOGENEITIES; SCATTERING; COHERENCE; WAVES AB Expressions are presented for the vertical profiles of the variances, integral length scales and structure-function parameters of temperature and wind velocity fluctuations for different turbulence regimes in an unstable atmospheric boundary layer. Based on these expressions, two ratios of velocity-to-temperature terms are obtained. The first of these ratios characterizes the relative contributions from wind velocity and temperature fluctuations to the statistical moments of a sound held in a turbulent atmosphere when this field is affected mainly by large-scale inhomogeneities. The second ratio characterizes these contributions in the opposite case when a sound field is affected mainly by relatively small-scale inhomogeneities in the inertial subrange. The vertical profiles of the second ratio, obtained for different meteorological conditions, are used to study the effects of wind velocity fluctuations on the echo signal measured by a monostatic sodar in a stratified. moving atmosphere. The common practice of interpreting returns from monostatic sodars solely in terms of the temperature structure-function parameter is found to be tenuous in many typical atmospheric conditions. C1 NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. USA, Res Lab, Adelphi, MD 20783 USA. RP Ostashev, VE (reprint author), NOAA, ERL, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. RI Wilson, D. Keith/A-4687-2012 OI Wilson, D. Keith/0000-0002-8020-6871 NR 15 TC 25 Z9 26 U1 0 U2 0 PU S HIRZEL VERLAG PI STUTTGART PA POSTFACH 10 10 61, D-70 009 STUTTGART, GERMANY SN 0001-7884 J9 ACUSTICA JI Acustica PD MAR-APR PY 2000 VL 86 IS 2 BP 260 EP 268 PG 9 WC Acoustics SC Acoustics GA 319UP UT WOS:000087361100006 ER PT J AU Rose, AH AF Rose, AH TI Annealing optical fiber: Applications and properties SO AMERICAN CERAMIC SOCIETY BULLETIN LA English DT Article ID CURRENT SENSORS AB Annealing optical fibers has made the optical fiber current sensor practical for monitoring and diagnostics done by utility companies. The detrimental effects of annealing can be made beneficial when applied to fiber depolarization and increased ultraviolet (UV) photosensitivity. C1 NIST, Div Optoelect, Boulder, CO USA. RP Rose, AH (reprint author), NIST, Div Optoelect, Boulder, CO USA. NR 6 TC 13 Z9 13 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7812 J9 AM CERAM SOC BULL JI Am. Ceram. Soc. Bull. PD MAR PY 2000 VL 79 IS 3 BP 40 EP 43 PG 4 WC Materials Science, Ceramics SC Materials Science GA 291WX UT WOS:000085763300002 ER PT J AU Phinney, KW AF Phinney, KW TI SFC of drug enantiomers SO ANALYTICAL CHEMISTRY LA English DT Article ID SUPERCRITICAL-FLUID-CHROMATOGRAPHY; CHIRAL STATIONARY-PHASE; SEPARATION; RESOLUTION; SELECTIVITY; ADDITIVES; LIQUID; HPLC C1 NIST, Gaithersburg, MD 20899 USA. RP Phinney, KW (reprint author), NIST, 100 Bur Dr,Mail Stop 8392, Gaithersburg, MD 20899 USA. NR 40 TC 60 Z9 62 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 MAR 1 PY 2000 VL 72 IS 5 BP 204A EP 211A DI 10.1021/ac0027542 PG 8 WC Chemistry, Analytical SC Chemistry GA 289DK UT WOS:000085605100016 PM 10739185 ER PT J AU Coursey, BM AF Coursey, BM TI ICRM'99: Radionuclide metrology techniques - Preface SO APPLIED RADIATION AND ISOTOPES LA English DT Editorial Material C1 NIST, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. RP Coursey, BM (reprint author), NIST, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. NR 5 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 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAR PY 2000 VL 52 IS 3 BP 311 EP 312 DI 10.1016/S0969-8043(99)00170-0 PG 2 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 287ZV UT WOS:000085538100001 ER PT J AU Unterweger, MP Lucas, LL AF Unterweger, MP Lucas, LL TI Calibration of the National Institute of Standards and Technology tritiated-water standards SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT Conference on Radionuclide Metrology and Its Applications (ICRM 99) CY JUN 07-11, 1999 CL CHARLES UNIV, LAW FAC, PRAGUE, CZECH REPUBLIC SP Int Comm Radionuclide Metrol HO CHARLES UNIV, LAW FAC AB Massic activity values obtained for NBS/NIST tritiated water SRMs 4927 and 4927E, using internal gas-proportional counting, are reported. The massic activity ratios of all of the available NBS/NIST tritiated water SRMs and samples of the Level 1 and Level 3 tritiated water standards produced by the National Physical Laboratory (NPL) in 1996 were measured using an extensive series of liquid-scintillation intercomparisons. New massic activity values obtained for the NPL standards, using the gas counting results for SRM 4927E and the results of the liquid-scintillation intercomparison, are also reported. A new determination of the half-life of tritium was made using massic activity data for SRM 4927 over a period of 38 years. The new value is (4504 +/- 9) (one standard deviation) days. This value differs significantly from the previous NBS/NIST value but is in good agreement with the value recommended in the Evaluated Nuclear Structure Data File (ENSDF). Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Radioact Grp, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. RP Unterweger, MP (reprint author), Natl Inst Stand & Technol, Radioact Grp, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. NR 5 TC 13 Z9 14 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAR PY 2000 VL 52 IS 3 BP 527 EP 531 DI 10.1016/S0969-8043(99)00205-5 PG 5 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 287ZV UT WOS:000085538100036 ER PT J AU Coursey, BM AF Coursey, BM TI Needs for radioactivity standards and measurements in the life sciences SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT Conference on Radionuclide Metrology and Its Applications (ICRM 99) CY JUN 07-11, 1999 CL CHARLES UNIV, LAW FAC, PRAGUE, CZECH REPUBLIC SP Int Comm Radionuclide Metrol HO CHARLES UNIV, LAW FAC ID PALLIATION AB For almost 100 years, radioactivity has been one of the major tools in medicine. Therapeutic applications that began with Ra-226 and Rn-222 implants have rapidly grown to include about 20 radionuclides with radiations specifically chosen to treat at different depths in tissue - ranging from a few millimeters for intravascular therapy to a few centimeters in the case of large solid tumors. Systemic treatments with radiopharmaceuticals have grown from the traditional I-131 to more than ten candidate nuclides which are to be labeled to tumor-specific radiopharmaceuticals. Diagnostic radiopharmaceuticals are used in over 13 million procedures in the United States annually. About 40 nuclides are under investigation for these applications including single photon emitters for SPECT (single photon emission computed tomography) and positron emitters for PET (positron emission tomography). In addition to the mainstays of therapeutic and diagnostic radiology, radionuclides are widely used for in vitro tracers in the life sciences and represent one of the main tools in the field of molecular biology. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Coursey, BM (reprint author), Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. NR 22 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAR PY 2000 VL 52 IS 3 BP 609 EP 614 DI 10.1016/S0969-8043(99)00218-3 PG 6 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 287ZV UT WOS:000085538100049 PM 10724414 ER PT J AU Zimmerman, BE Cessna, JT AF Zimmerman, BE Cessna, JT TI Experimental determinations of commercial 'dose calibrator' settings for nuclides used in nuclear medicine SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT Conference on Radionuclide Metrology and Its Applications (ICRM 99) CY JUN 07-11, 1999 CL CHARLES UNIV, LAW FAC, PRAGUE, CZECH REPUBLIC SP Int Comm Radionuclide Metrol HO CHARLES UNIV, LAW FAC AB Commercial reentrant ionization chambers ('dose calibrators') have become the de facto standard instrument for making radioactivity measurements in the radiopharmaceutical industry. Accurate activity measurements, however, depend on the application of the correct calibration factor (dial setting) for the radionuclide in the exact measurement geometry for that particular instrument. Two methods are described for the experimental determination of dial settings for the Capintec CRC-12 dose calibrator. Using these methods, we have determined new calibration factors for F-18, Cu-62, Re-186 and Re-188 in several geometries. These new factors are presented, along with previously determined settings, for nuclides commonly used in nuclear medicine. The differences between the calibration factors for the different geometries, as well as the differences between the manufacturer's recommended setting underscore the need for empirically determined dose calibrator settings. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. RP Zimmerman, BE (reprint author), Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. NR 5 TC 26 Z9 27 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAR PY 2000 VL 52 IS 3 BP 615 EP 619 DI 10.1016/S0969-8043(99)00219-5 PG 5 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 287ZV UT WOS:000085538100050 PM 10724415 ER PT J AU Lund, SA Fulton, MH Key, PB AF Lund, SA Fulton, MH Key, PB TI The sensitivity of grass shrimp, Palaemonetes pugio, embryos to organophosphate pesticide induced acetylcholinesterase inhibition SO AQUATIC TOXICOLOGY LA English DT Article DE chlorpyrifos; malathion; acetylcholinesterase; grass shrimp embryos ID BIOCONCENTRATION FACTORS; FENVALERATE; MALATHION; CHEMICALS; TOXICITY AB Grass shrimp, Palaemonetes pugio, are common inhabitants of salt marshes along the Atlantic and Gulf coasts of North America. Grass shrimp embryos are brooded externally on the abdomen of adult females for about 2 weeks prior to hatching. In South Carolina, the spring spawning period for grass shrimp coincides with the period of peak pesticide application on crops grown along the South Carolina coast. Thus, grass shrimp of all developmental stages are at risk of exposure to pesticides present in nonpoint source agricultural runoff. Organophosphate (OP) insecticides are commonly applied agricultural chemicals which produce toxicity by inhibiting the nervous system enzyme, acetylcholinesterase (AChE). The purpose of this study was to examine the development of AChE activity in grass shrimp embryos and to assess their sensitivity to OP-induced AChE inhibition. Embryos were exposed for 24 h to either chlorpyrifos or malathion. All exposure concentrations were nominal and ranged from 0 to 2.00 mu g l(-1) for chlorpyrifos and from 0 to 120.00 mu g l(-1) for malathion. Quantifiable levels of AChE activity first appeared at Stage V of development and increased as embryonic development progressed. AChE inhibition by the OPs was assessed in Stage VI and Stage VII embryos. Both stages of embryos were more sensitive to chlorpyrifos than malathion. The 24-h Effective Concentration (EC(50)) values for chlorpyrifos were 0.49 mu g l(-1) (95% C.I. = 0.33-0.77 mu g l(-1)) and 0.36 pg l(-1) (95% C.I. = 0.33-0.38 mu g l(-1)) for Stage VI and Stage VII embryos, respectively. In comparison, malathion 24-h EC(50) values were 55.53 mu g l(-1) (95% C.I. = 22.08-80.73 mu g l(-1)) for Stage VI embryos and 29.93 mu g l(-1) (95% C.I. = 25.22-44.22 mu g l(-1)) for Stage VII embryos. For both OPs, there were no significant differences in the EC(50) values calculated for Stage VI and Stage VII embryos; however, AChE inhibition was significantly (P less than or equal to 0.05) greater in Stage VII embryos at the two highest exposure concentrations for each insecticide. A comparison of the results of these embryo tests with those found for adult and larval toxicity tests indicated that embryos were at least as sensitive to both the OPs as larval and adult grass shrimp. Embryo bioassays provide a number of important advantages over traditional laboratory toxicity tests including reduced laboratory space requirements, large numbers of embryos from a few ovigerous females, and small volumes of waste. (C) 2000 Published by Elsevier Science B.V. C1 NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res Charleston, Charleston, SC 29412 USA. RP Lund, SA (reprint author), NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res Charleston, 219 Ft Johnson Rd, Charleston, SC 29412 USA. EM shannon.lund@noaa.gov NR 34 TC 22 Z9 27 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD MAR PY 2000 VL 48 IS 2-3 BP 127 EP 134 DI 10.1016/S0166-445X(99)00053-3 PG 8 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA 291JZ UT WOS:000085732100006 ER PT J AU Terndrup, DM Stauffer, JR Pinsonneault, MH Sills, A Yuan, YQ Jones, BF Fischer, D Krishnamurthi, A AF Terndrup, DM Stauffer, JR Pinsonneault, MH Sills, A Yuan, YQ Jones, BF Fischer, D Krishnamurthi, A TI Rotational velocities of low-mass stars in the Pleiades and Hyades SO ASTRONOMICAL JOURNAL LA English DT Article DE open clusters and associations : individual (Pleiades, Hyades); stars : magnetic fields; stars : rotation ID SOLAR-TYPE STARS; T-TAURI STARS; MAIN-SEQUENCE STARS; PROPER-MOTION MEMBERSHIP; ALPHA-PERSEI CLUSTER; LITHIUM DEPLETION; ANGULAR-MOMENTUM; M-DWARF; CHROMOSPHERIC ACTIVITY; RADIAL-VELOCITIES AB We have obtained high-resolution spectra of 89 M dwarf members of the Pleiades and Hyades and have derived radial velocities, Ha equivalent widths, and spectroscopic rotational velocities for these stars. Typical masses of the newly observed Pleiades and Hyades stars are similar to 0.4 M. and similar to 0.2 M., respectively. We combine our new observations with previously published data to explore the rotational evolution of young stars with M less than or equal to 0.4 M.. The average rotation rate in the Hyades (age 600 Myr) is about 0.4 times that in the Pleiades (110 Myr), and the mean equivalent widths of H alpha are also lower. As found in previous studies, the correlation between rotation and chromospheric activity is identical in both clusters, implying that the lower activity in the Hyades is a result of the lower rotation rates. We show that a simple scaling of the Pleiades rotational distribution for M less than or equal to 0.4 M., corrected for the effects of structural evolution, matches that of the Hyades if the average angular momentum loss from the Pleiades to the Hyades age is factor of approximate to 6. This suggests that the distribution of initial angular momenta and disk-locking lifetimes for the lowest mass stars was similar in both clusters. We argue that this result provides further evidence for a saturation of the angular momentum loss rate at high rotational velocities. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. Univ Calif Santa Cruz, Lick Observ, Board Studies Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Terndrup, DM (reprint author), Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. OI Fischer, Debra/0000-0003-2221-0861 NR 94 TC 84 Z9 84 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 MAR PY 2000 VL 119 IS 3 BP 1303 EP 1316 DI 10.1086/301259 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 297CA UT WOS:000086062900023 ER PT J AU Garcia, HA AF Garcia, HA TI Thermal-spatial analysis of medium and large solar flares, 1976 to 1996 SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE Sun : flares; Sun : X-rays, gamma rays ID CORONAL LOOPS; SCALING LAWS; TEMPERATURE; YOHKOH; MORPHOLOGY; DYNAMICS; PLASMA; MODEL AB Approximately 1100 moderate to large solar flares observed in soft X-rays by the GOES spacecraft, operating between 1976 and 1996, are analyzed individually for thermal and spatial structure by a model that utilizes discrete X-ray measurements, the ensemble X-ray light curve, and scaling laws relating certain thermal properties to spatial dimension. This method endeavors to reproduce a flare's thermal structure in terms of its loop geometry from spatially unresolved measurements, invoking a theoretically conceived and empirically confirmed relationship between the loop scale and temporal behavior of flares. Used in conjunction with a well-known, quasi-static equilibrium scaling law relating loop scale to key thermal parameters, a comprehensive solution of global thermal structure can be closed in the context of this model. The essential characteristics of this model were described by Garcia in an earlier paper showing the step by step procedure for computing the length, cross section, volume, density, mass, and thermal energy of an individual hare loop. The primary purpose of the present work is to utilize the model and method presented by Garcia, based on a small group of flares, to study a much larger sample of hares in order to determine their average characteristics of the above parameters over an extended range of X-ray intensity and size. The ability to utilize spatially unresolved X-ray data to analyze the structure of individual flares at small cost opens the possibility of investigating the average behavior of large populations of X-ray flares, exploiting the largely untapped reservoir of data accumulated since the advent of operational geosynchronous weather satellites. C1 NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP NOAA, Space Environm Ctr, 325 Broadway, Boulder, CO 80303 USA. EM hgarcia@sec.noaa.gov NR 17 TC 24 Z9 25 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 2000 VL 127 IS 1 BP 189 EP 210 DI 10.1086/313312 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 318CE UT WOS:000087265700010 ER PT J AU Grachev, AA Fairall, CW Bradley, EF AF Grachev, AA Fairall, CW Bradley, EF TI Convective profile constants revisited SO BOUNDARY-LAYER METEOROLOGY LA English DT Article DE Monin-Obukhov theory; flux-gradient relations; Businger-Dyer formulae; free convection ID ATMOSPHERIC SURFACE-LAYER; BOUNDARY-LAYER; WIND; SEA; PARAMETERIZATION; EVAPORATION; TEMPERATURE; VELOCITY; FLUXES; MODEL AB This paper examines the interpolation between Businger-Dyer (Kansas-type) formulae, phi(u) = (1 -16 zeta)(-1/4) and phi(t) = (1 - 16 zeta)(-1/2), and free convection forms. Based on matching constraints, the constants, a(u) and a(t), in the convective flux-gradient relations, phi(u) = (1 - a(u)zeta )(-1/3) and phi(t) = (1 - a(t)zeta )(-1/3), are determined. It is shown that a(u) and a(t) cannot be completely independent if convective forms are blended with the Kansas formulae. In other words, these relationships already carry information about a(u) and a(t). This follows because the Kansas relations cover a wide stability range (up to zeta = -2), which includes a lower part of the convective sublayer (about 0.1 < -zeta < 2). Thus, there is a subrange where both Kansas and convective formulae are valid. Matching Kansas formulae and free convection relations within the subrange 0.1 < -zeta < 2 and independently smoothing of the blending function are used to determine a(u) and a(t). The values a(u) = 10 for velocity and a(t) = 34 for scalars (temperature and humidity) give a good fit. This new approach eliminates the need for additional independent model constants and yields a 'smooth' blending between Kansas and free-convection profile forms in the COARE bulk algorithm. C1 Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. Russian Acad Sci, Inst Atmospher Phys, Moscow 109017, Russia. CSIRO Land & Water, Canberra, ACT 2601, Australia. RP Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, R-ET7,325 Broadway, Boulder, CO 80303 USA. EM agrachev@etl.noaa.gov RI Bradley, Frank/I-6574-2013; OI GRACHEV, ANDREY/0000-0002-7143-0820 NR 40 TC 41 Z9 41 U1 1 U2 6 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0006-8314 EI 1573-1472 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD MAR PY 2000 VL 94 IS 3 BP 495 EP 515 DI 10.1023/A:1002452529672 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 286BB UT WOS:000085422800006 ER PT J AU Jeffrey, CFG AF Jeffrey, CFG TI Annual, coastal and seasonal variation in Grenadian demersal fisheries (1986-1993) and implications SO BULLETIN OF MARINE SCIENCE LA English DT Article ID CORAL-REEF FISHES; NASSAU GROUPER; COMMUNITIES; BIOMASS AB I examined trends in the exploitation of demersal reef fishes in Grenada from 1986 to 1993 to determine if the Island's reef fishery resources were declining. I show that mean monthly catch per unit effort of groupers and snappers declined with increasing fishing intensity during the study period, suggesting overfishing. Mean monthly yields of other less desirable stocks remained constant but were never more than 3% of the total demersal yield. Mean yields of all fishes except snappers were higher on the east coast than on the west coast and were higher for all fishes during July to November than December to June. Tourism and the Island's population increased during the same period, were inversely correlated with annual yields of demersal fishes, and may have driven fishery harvest. Although demersal reef fishes comprised only 7% of Grenada's fishery harvest, they are important sources of food and income to local fishers. Declining demersal catches may not be critical at present, but the absence of groupers and large snappers From coral reefs in more economically developed islands (e.g., Barbados, Bermuda, and U.S. Virgin Islands) suggests that the fate of Grenada's demersal fisheries may be similar if observed trends continue. Regulations are necessary to sustain Grenada's demersal fisheries. C1 Univ Georgia, Inst Ecol, Athens, GA 30602 USA. Univ Georgia, Program Conservat Ecol & Sustainable Dev, Athens, GA 30602 USA. RP Jeffrey, CFG (reprint author), NOAA, Natl Ocean Serv, N-SCI-1 SSMC-4 RM 9222,1305 EW Highway, Silver Spring, MD 20910 USA. NR 32 TC 4 Z9 4 U1 0 U2 3 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAR PY 2000 VL 66 IS 2 BP 305 EP 319 PG 15 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 295ZJ UT WOS:000085998300003 ER PT J AU Meehl, GA Karl, T Easterling, DR Changnon, S Pielke, R Changnon, D Evans, J Groisman, PY Knutson, TR Kunkel, KE Mearns, LO Parmesan, C Pulwarty, R Root, T Sylves, RT Whetton, P Zwiers, F AF Meehl, GA Karl, T Easterling, DR Changnon, S Pielke, R Changnon, D Evans, J Groisman, PY Knutson, TR Kunkel, KE Mearns, LO Parmesan, C Pulwarty, R Root, T Sylves, RT Whetton, P Zwiers, F TI An introduction to trends in extreme weather and climate events: Observations, socioeconomic impacts, terrestrial ecological impacts, and model projections SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID EXCEEDANCES AB Weather and climatic extremes can have serious and damaging effects on human society and infrastructure as well as on ecosystems and wildlife. Thus, they are usually the main focus of attention of the news media in reports on climate. There are some indications from observations concerning how climatic extremes may have changed in the past. Climate models show how they could change in the future either due to natural climate fluctuations or under conditions of greenhouse gas-induced warming. These observed and modeled changes relate directly to the understanding of socioeconomic and ecological impacts related to extremes. C1 Natl Ctr Atmospher Res, Climate & Global Dynam Div, Boulder, CO 80307 USA. Natl Climate Data Ctr, Asheville, NC USA. Illinois State Water Survey, Champaign, IL 61820 USA. No Illinois Univ, De Kalb, IL 60115 USA. Penn State Univ, University Pk, PA 16802 USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. Univ Texas, Austin, TX 78712 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Colorado, Boulder, CO 80309 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Delaware, Newark, DE USA. CSIRO, Aspendale, Vic, Australia. CCCMA, Victoria, BC, Canada. RP Meehl, GA (reprint author), Natl Ctr Atmospher Res, Climate & Global Dynam Div, POB 3000, Boulder, CO 80307 USA. RI Pielke, Roger/A-5015-2009; Whetton, Penny/A-6885-2012; Kunkel, Kenneth/C-7280-2015 OI Kunkel, Kenneth/0000-0001-6667-7047 NR 14 TC 316 Z9 356 U1 9 U2 87 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2000 VL 81 IS 3 BP 413 EP 416 DI 10.1175/1520-0477(2000)081<0413:AITTIE>2.3.CO;2 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 305EB UT WOS:000086525500001 ER PT J AU Easterling, DR Evans, JL Groisman, PY Karl, TR Kunkel, KE Ambenje, P AF Easterling, DR Evans, JL Groisman, PY Karl, TR Kunkel, KE Ambenje, P TI Observed variability and trends in extreme climate events: A brief review SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Review ID TROPICAL CYCLONE ACTIVITY; LONG-TERM TRENDS; 1995 HEAT-WAVE; UNITED-STATES; ATLANTIC HURRICANES; AUSTRALIAN REGION; WATER-VAPOR; PRECIPITATION; TEMPERATURE; WEATHER AB Variations and trends in extreme climate events have only recently received much attention. Exponentially increasing economic losses, coupled with an increase in deaths due to these events, have focused attention on the possibility that these events are increasing in frequency. One of the major problems in examining the climate record for changes in extremes is a lack of high-quality, long-term data. In some areas of the world increases in extreme events are apparent, while in others there appears to be a decline. Based on this information increased ability to monitor and detect multidecadal variations and trends is critical to begin to detect any observed changes and understand their origins. C1 NOAA, NESDIS, Natl Climat Data Ctr, Asheville, NC 28801 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Illinois State Water Survey, Champaign, IL 61820 USA. Kenyan Meteorol Dept, Drought Monitoring Ctr, Nairobi, Kenya. RP Easterling, DR (reprint author), NOAA, NESDIS, Natl Climat Data Ctr, 151 Patton Ave,Room 120, Asheville, NC 28801 USA. EM deasterl@ncdc.noaa.gov RI Kunkel, Kenneth/C-7280-2015 OI Kunkel, Kenneth/0000-0001-6667-7047 NR 42 TC 585 Z9 729 U1 29 U2 220 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2000 VL 81 IS 3 BP 417 EP 425 DI 10.1175/1520-0477(2000)081<0417:OVATIE>2.3.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 305EB UT WOS:000086525500002 ER PT J AU Meehl, GA Zwiers, F Evans, J Knutson, T Mearns, L Whetton, P AF Meehl, GA Zwiers, F Evans, J Knutson, T Mearns, L Whetton, P TI Trends in extreme weather and climate events: Issues related to modeling extremes in projections of future climate change SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID INCREASED ATMOSPHERIC CO2; ASIAN SUMMER MONSOON; TROPICAL PACIFIC; GREENHOUSE-GAS; SURFACE-TEMPERATURE; SIMULATED CHANGES; VARIABILITY; PRECIPITATION; FREQUENCY; INTENSITY AB Projections of statistical aspects of weather and climate extremes can be derived from climate models representing possible future climate states. Some of the recent models have reproduced results previously reported in the Intergovernmental Panel on Climate Change (IPCC) Second Assessment Report, such as a greater frequency of extreme warm days and lower frequency of extreme cold days associated with a warmer mean climate, a decrease in diurnal temperature range associated with higher nighttime temperatures, increased precipitation intensity, midcontinent summer drying, decreasing daily variability of surface temperature in winter, and increasing variability of northern midlatitude summer surface temperatures. This reconfirmation of previous results gives an increased confidence in the credibility of the models, though agreement among models does not guarantee those changes will occur. New results since the IPCC Second Assessment Report indicate a possible increase of extreme heat stress events in a warmer climate, an increase of cooling degree days and decrease in heating degree days, an increase of precipitation extremes such that there is a decrease in return periods for 20-yr extreme precipitation events, and more detailed analyses of possible changes in 20-yr return values for extreme maximum and minimum temperatures. Additionally, recent studies are now addressing interannual and synoptic time and space scale processes that affect weather and climate extremes, such as tropical cyclones, El Nino effects, and extratropical storms. However, current climate models are not yet in agreement with respect to possible future changes in such features. C1 Natl Ctr Atmospher Res, Climat & Global Dynam Div, Boulder, CO 80307 USA. Canadian Ctr Modelling & Anal, Victoria, BC, Canada. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. CSIRO, Aspendale, Vic, Australia. Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Meehl, GA (reprint author), Natl Ctr Atmospher Res, Climat & Global Dynam Div, POB 3000, Boulder, CO 80307 USA. RI Whetton, Penny/A-6885-2012 NR 57 TC 226 Z9 237 U1 8 U2 72 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2000 VL 81 IS 3 BP 427 EP 436 DI 10.1175/1520-0477(2000)081<0427:TIEWAC>2.3.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 305EB UT WOS:000086525500003 ER PT J AU Changnon, SA Pielke, RA Changnon, D Sylves, RT Pulwarty, R AF Changnon, SA Pielke, RA Changnon, D Sylves, RT Pulwarty, R TI Human factors explain the increased losses from weather and climate extremes SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID INSURANCE INDUSTRY; UNITED-STATES AB Societal impacts from weather and climate extremes, and trends in those impacts, are a function of both climate and society. United States losses resulting from weather extremes have grown steadily with time. Insured property losses have trebled since 1960, but deaths from extremes have not grown except for those due to floods and heat waves. Data on losses are difficult to find and must be carefully adjusted before meaningful assessments can be made. Adjustments to historical loss data assembled since the late 1940s shows that most of the upward trends found in financial losses are due to societal shifts leading to ever-growing vulnerability to weather and climate extremes. Geographical locations of the large loss trends establish that population growth and demographic shifts are the major factors behind the increasing losses from weather-climate extremes. Most weather and climate extremes in the United States do not exhibit steady, multidecadal increases found in their loss values. Without major changes in societal responses to weather and climate extremes, it is reasonable to predict ever-increasing losses even without any detrimental climate changes. Recognition of these trends in societal vulnerability to weather-climate extremes suggests that the present focus on mitigating the greenhouse effect should be complemented by a greater emphasis on adaptation. Identifying and understanding this societal vulnerability has great importance for understanding the nation's economy, in guiding governmental policies, and for planning for future mitigative activities including ways for society to adapt to possible effects of a changing climate. C1 Illinois State Water Survey, Atmospher Environm Sect, Champaign, IL 61820 USA. Natl Ctr Atmospher Res, Environm & Societal Impacts Grp, Boulder, CO 80307 USA. No Illinois Univ, Dept Geog, De Kalb, IL 60115 USA. Univ Delaware, Dept Polit Sci, Newark, DE USA. NOAA, Off Global Programs, Silver Springs, MD USA. RP Changnon, SA (reprint author), Illinois State Water Survey, Atmospher Environm Sect, 2204 Griffith Dr, Champaign, IL 61820 USA. NR 33 TC 130 Z9 178 U1 4 U2 30 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2000 VL 81 IS 3 BP 437 EP 442 DI 10.1175/1520-0477(2000)081<0437:HFETIL>2.3.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 305EB UT WOS:000086525500004 ER PT J AU Johnson, JT Eilts, MD Ruth, D Goodman, W Rothfusz, L AF Johnson, JT Eilts, MD Ruth, D Goodman, W Rothfusz, L TI Warning operations in support of the 1996 Centennial Olympic Games SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB During the summer of 1996, the National Weather Service (NWS) provided weather support for the Centennial Olympic Games in Atlanta, Georgia. This weather support effort presented many challenges, particularly in the area of providing short-term forecast (watch) and warning support. Topping the list of challenges was working with a customer with different weather information needs than the general public. The needs of the venue and competition management were much more detailed than the NWS traditionally is accustomed to and the thresholds for various phenomena were very low (e.g., warnings for the occurrence of any rain were issued rather than the more traditional NWS severe thunderstorm warning). This paper discusses many of the challenges faced and met by the Olympic Weather Support Office (OWSO). Details are provided on the weather warning requirements of the Olympic venue and competition management, the watch/warning strategy utilized by the OWSO, and the resulting performance of the office. More than 1200 watches and warnings were issued during the period of Olympic weather support. These bulletins were for phenomena ranging from dew formation and low visibility to lightning and heavy rain. Several emerging technologies were employed for warning operations in the OWSO, including the Warning Decision Support System and the Watch/Warning/Advisory package. These hardware/software solutions appear to have made a positive impact on the performance of the office in meeting the challenges of this unique warning situation. C1 Natl Severe Storms Lab, Real Time Applicat Prototyping & Idea Dev, Norman, OK 73069 USA. Natl Weather Serv, Tech Dev Lab, Silver Spring, MD USA. RP Johnson, JT (reprint author), Natl Severe Storms Lab, Real Time Applicat Prototyping & Idea Dev, 1313 Halley Circle, Norman, OK 73069 USA. NR 11 TC 6 Z9 11 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2000 VL 81 IS 3 BP 543 EP 554 DI 10.1175/1520-0477(2000)081<0543:WOISOT>2.3.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 305EB UT WOS:000086525500011 ER PT J AU Ansara, I Burton, B Chen, Q Hillert, M Guillermet, AF Fries, SG Lukas, HL Seifert, HJ Oates, WA AF Ansara, I Burton, B Chen, Q Hillert, M Guillermet, AF Fries, SG Lukas, HL Seifert, HJ Oates, WA TI Applications of Computational Thermodynamics: Group 2: Models for composition dependence SO CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY LA English DT Article; Proceedings Paper CT International Workshop on Applications of Computational Thermodynamics CY 1997 CL SCHLOSS RINGBERG, GERMANY SP Max Planck Inst Metallforsch, Stuttgart & Sci Grp Thermodata Europe ID SCHLOSS-RINGBERG; PHASE-DIAGRAMS; ALLOYS; SYSTEM; WORKSHOP AB A variety of problems related to modelling of composition dependent Gibbs energies and other thermodynamic properties is discussed. The current procedure adopted in the CALPHAD method for modelling intermediate metallic nonstoichiometric phases is described and analysed. Some possibilities towards more physical approaches are pointed out. C1 ENSEEG, Thermodynam & Physicochim Met Lab, F-38042 Grenoble, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Royal Inst Technol, Dept Mat Sci & Engn, SE-10044 Stockholm, Sweden. Ctr Atom Bariloche, Cons Nac Invest Cient Tecn, San Carlos De Bariloche, Rio Negro, Argentina. Rhein Westfal TH Aachen, ACCESS EV, D-52072 Aachen, Germany. Univ Stuttgart, Max Planck Inst Met Forsch, D-70569 Stuttgart, Germany. Univ Stuttgart, Inst Nichtmet Anogan Mat, D-70569 Stuttgart, Germany. Univ Salford, Sci Res Inst, Salford M5 4WT, Lancs, England. RP Ansara, I (reprint author), ENSEEG, Thermodynam & Physicochim Met Lab, BP 75, F-38042 Grenoble, France. RI Fries, suzana/A-5280-2013 NR 26 TC 27 Z9 27 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0364-5916 J9 CALPHAD JI Calphad-Comput. Coupling Ph. Diagrams Thermochem. PD MAR PY 2000 VL 24 IS 1 BP 19 EP 40 DI 10.1016/S0364-5916(00)00013-4 PG 22 WC Thermodynamics; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Thermodynamics; Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 306MM UT WOS:000086600500003 ER PT J AU Kattner, UR Eriksson, G Hahn, I Schmid-Fetzer, R Sundman, B Swamy, V Kussmaul, A Spencer, PJ Anderson, TJ Chart, TG Silva, ACE Jansson, B Lee, BJ Schalin, M AF Kattner, UR Eriksson, G Hahn, I Schmid-Fetzer, R Sundman, B Swamy, V Kussmaul, A Spencer, PJ Anderson, TJ Chart, TG Silva, ACE Jansson, B Lee, BJ Schalin, M TI Applications of Computational Thermodynamics: Groups 4 and 5: Use of thermodynamic software in process modelling and new applications of thermodynamic calculations SO CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY LA English DT Article; Proceedings Paper CT International Workshop on Applications of Computational Thermodynamics CY 1997 CL SCHLOSS RINGBERG, GERMANY SP Max Planck Inst Metallforsch, Stuttgart & Sci Grp Thermodata Europe ID INTERFACE REACTION-PRODUCTS; GIBBS FREE-ENERGY; TI-AL-O; SOLIDIFICATION PROCESSES; MULTICOMPONENT ALLOYS; COMPUTER-SIMULATIONS; RAPID SOLIDIFICATION; MAGMATIC PROCESSES; AQUEOUS-SOLUTIONS; PHASE-EQUILIBRIA C1 NIST, Gaithersburg, MD 20899 USA. Siemens AG, D-8000 Munich, Germany. Tech Univ Clausthal, D-3392 Clausthal Zellerfeld, Germany. KTH, Stockholm, Sweden. CSIRO, Clayton, Vic 3168, Australia. MPI, Stuttgart, Germany. Rhein Westfal TH Aachen, D-5100 Aachen, Germany. Univ Florida, Gainesville, FL USA. Chart Associates, Ashford, Kent, England. UFF, Volta Redonda, Brazil. SECO Tools AB, Fagersta, Sweden. KRISS, Taejon, South Korea. RP Kattner, UR (reprint author), NIST, Gaithersburg, MD 20899 USA. RI Swamy, Varghese/C-2851-2013; Costa e Silva, Andre /L-5134-2016 OI Costa e Silva, Andre /0000-0002-0513-8338 NR 206 TC 16 Z9 17 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0364-5916 EI 1873-2984 J9 CALPHAD JI Calphad-Comput. Coupling Ph. Diagrams Thermochem. PD MAR PY 2000 VL 24 IS 1 BP 55 EP 94 PG 40 WC Thermodynamics; Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Thermodynamics; Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 306MM UT WOS:000086600500005 ER PT J AU Berejikian, BA Tezak, EP Flagg, TA LaRae, AL Kummerow, E Mahnken, CVW AF Berejikian, BA Tezak, EP Flagg, TA LaRae, AL Kummerow, E Mahnken, CVW TI Social dominance, growth, and habitat use of age-0 steelhead (Oncorhynchus mykiss) grown in enriched and conventional hatchery rearing environments SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID JUVENILE COHO SALMON; AGONISTIC BEHAVIOR; FOOD DISTRIBUTION; ATLANTIC SALMON; CHINOOK SALMON; TERRITORY SIZE; WILD ANCESTRY; BROWN TROUT; EXPERIENCE; GAIRDNERI AB This study investigated whether culturing age-0 steelhead (Oncorhynchus mykiss) in habitat-enriched rearing tanks, containing a combination of in-water structure, underwater feeders, and overhead cover, affected competitive ability and habitat use compared with juveniles cultured in more conventional vessels. In laboratory tests, steelhead juveniles grown in the enriched tanks socially dominated size-matched competitors grown in conventional tanks. When both treatments were introduced into separate sections of a quasi-natural stream, no differences in growth were found between them. However, when intermixed, fish reared in the enriched tanks grew at a higher rate than conventionally reared competitors, suggesting greater competitive ability of juveniles grown in the enriched tanks. Visual isolation and defensible food resources in combination in the enriched tanks were considered as the primary factors causing the observed competitive asymmetries. Steelhead juveniles from the two rearing environments exhibited very similar use of woody structure in the quasi-natural stream, both in the presence and in the absence of mutual competition. Rearing steelhead in more naturalistic environments could result in hatchery fish that behave and integrate into the postrelease (natural) environment in a manner more similar to wild fish. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Manchester Marine Expt Stn, Manchester, WA 98353 USA. RP Berejikian, BA (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Manchester Marine Expt Stn, POB 130, Manchester, WA 98353 USA. NR 41 TC 41 Z9 41 U1 1 U2 9 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAR PY 2000 VL 57 IS 3 BP 628 EP 636 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 296VA UT WOS:000086046400013 ER PT J AU Rumminger, MD Linteris, GT AF Rumminger, MD Linteris, GT TI Inhibition of premixed carbon monoxide-hydrogen-oxygen-nitrogen flames by iron pentacarbonyl SO COMBUSTION AND FLAME LA English DT Article ID METHANE-AIR FLAMES; MECHANISM; CF3BR AB This paper presents measurements of the burning velocity of premixed CO-H-2-O-2-N, flames with and without the inhibitor Fe(CO)(5) over a range of initial H-2 and O-2 mole fractions. A numerical model is used to simulate the flame inhibition using a gas-phase chemical mechanism. For the uninhibited flames, predictions of burning velocity are excellent and for the inhibited flames, the qualitative agreement is good. The agreement depends strongly on the rate of the CO + OH <-> CO2 + H reaction and the rates of several key iron reactions in catalytic H- and O-atom scavenging cycles. Most of the chemical inhibition occurs through a catalytic cycle that converts O atoms into O-2 molecules. This O-atom cycle is not important in methane flames. The H-atom cycle that causes most of the radical scavenging in the methane flames is also active in CO-H-2 flames, but is of secondary importance. To vary the role of the H- and O-atom radical pools, the experiments and calculations are performed over a range of oxygen and hydrogen mole fraction. The degree of inhibition is shown to be related to the fraction of the net H- and O-atom destruction through the iron species catalytic cycles. The O-atom cycle saturates at a relatively low inhibitor mole fraction (similar to 100 ppm), whereas the H-atom cycle saturates at a much higher inhibitor mole fraction (similar to 400 ppm). The calculations reinforce the previously suggested idea that catalytic cycle saturation effects may limit the achievable degree of chemical inhibition. Published by Elsevier Science Inc. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Linteris, GT (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 53 TC 41 Z9 42 U1 0 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAR PY 2000 VL 120 IS 4 BP 451 EP 464 DI 10.1016/S0010-2180(99)00114-5 PG 14 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 279UQ UT WOS:000085063800005 ER PT J AU Elloumi, O Golmie, N Afifi, H Su, D AF Elloumi, O Golmie, N Afifi, H Su, D TI A simulation-based study of TCP dynamics over HFC networks SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE congestion avoidance; TCP; ATM; ACK compression; HFC AB New broadband access technologies such as hybrid fiber coaxial (HFC) are likely to provide fast and cost effective support to a variety of applications including video on demand (VoD), inter-active computer games, and Internet-type applications such as Web browsing, ftp, e-mail, and telephony. Since most of these applications use TCP as the transport layer protocol, the key to their efficiency largely depends on TCP protocol performance. We investigate the performance of TCP in terms of effective throughput in an HFC network environment using different load conditions and network buffer sizes. We find that TCP experiences low throughput as a result of the well-known problem of ACK compression. An algorithm that controls ACK spacing is introduced to improve TCP performance. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Alcatel Corp Res Ctr, B-2018 Antwerp, Belgium. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Ecole Natl Super Telecommun Bretagne, F-35512 Cesson Sevigne, France. RP Elloumi, O (reprint author), Alcatel Corp Res Ctr, Francis Wellespl 1, B-2018 Antwerp, Belgium. NR 22 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD MAR PY 2000 VL 32 IS 3 BP 307 EP 323 DI 10.1016/S1389-1286(99)00139-5 PG 17 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 302XR UT WOS:000086392200003 ER PT J AU Bruckner, AW Bruckner, RJ Sollins, P AF Bruckner, AW Bruckner, RJ Sollins, P TI Parrotfish predation on live coral: "spot biting" and "focused biting" SO CORAL REEFS LA English DT Article ID SPARISOMA-VIRIDE C1 Natl Marine Fisheries Serv, Off Protected Resources, Silver Spring, MD 20910 USA. RP Bruckner, AW (reprint author), Natl Marine Fisheries Serv, Off Protected Resources, Silver Spring, MD 20910 USA. NR 5 TC 30 Z9 32 U1 1 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD MAR PY 2000 VL 19 IS 1 BP 50 EP 50 DI 10.1007/s003380050225 PG 1 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 312WA UT WOS:000086965900006 ER PT J AU Tellez, CM Cole, KD AF Tellez, CM Cole, KD TI Preparative electrochromatography of proteins in various types of porous media SO ELECTROPHORESIS LA English DT Article; Proceedings Paper CT Meeting of the American-Electrophoresis-Society CY AUG 08-10, 1999 CL BETHESDA, MARYLAND SP Amer Electrophoresis Soc DE protein electrochromatography; preparative separation; beta-lactoglobulin; whey proteins; agarose digestion; dextranase digestion ID FIELD-FLOW FRACTIONATION; CAPILLARY-ELECTROPHORESIS; MILK-PROTEINS; WHEY; DNA; CHROMATOGRAPHY; PURIFICATION; DIFFUSION; AGARASE; COLUMN AB The performance of commercial and enzymatically modified size-exclusion (SE) gels in electrochromatography was compared for preparative protein separations. Dextran and agarose-based SE gels were subjected to enzymatic digestion under mild conditions. This treatment partially hydrolyzed the gel matrix modifying its pore size distribution. Enzymatic treatment of agarose-based SE gels was found to increase the resolution of the separation. Successful separation of preparative amounts of the A and B forms of beta-lactoglobulin (difference in electrophoretic mobility of 8.5%) was achieved with a high degree of purity using agarose-based SE gels. The four major whey proteins, beta-lactoglobulin, alpha-lactalbumin, BSA and immunoglobulins, were purified from an acid whey preparation. The degree of retention of a protein in electrochromatography followed their free-solution electrophoretic mobility (mu) when the protein was able to enter the gel pores and the ratio of diffusion/mu when the protein was excluded. C1 Natl Inst Stand & Technol, Bioproc Engn Grp, Biotechnol Div, Gaithersburg, MD 20899 USA. Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. RP Cole, KD (reprint author), Natl Inst Stand & Technol, Bioproc Engn Grp, Biotechnol Div, Gaithersburg, MD 20899 USA. NR 38 TC 18 Z9 19 U1 0 U2 3 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD MAR PY 2000 VL 21 IS 5 BP 1001 EP 1009 DI 10.1002/(SICI)1522-2683(20000301)21:5<1001::AID-ELPS1001>3.0.CO;2-3 PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 300ND UT WOS:000086258300024 PM 10768787 ER PT J AU Cole, KD Tellez, CM Blakesley, RW AF Cole, KD Tellez, CM Blakesley, RW TI Separation of different physical forms of plasmid DNA using a combination of low electric field strength and flow in porous media: Effect of different field gradients and porosity of the media SO ELECTROPHORESIS LA English DT Article; Proceedings Paper CT Meeting of the American-Electrophoresis-Society CY AUG 08-10, 1999 CL BETHESDA, MARYLAND SP Amer Electrophoresis Soc DE plasmid DNA; electrochromatography ID HUMAN GENE-THERAPY; GEL-ELECTROPHORESIS; CAPILLARY ELECTROCHROMATOGRAPHY; FRACTIONATION; VECTORS AB The retention of different physical forms of DNA by an electric field in a chromatography system was studied. We were able to effectively separate the supercoiled and the open circular forms of plasmid DNA using this type of electrochromatography system. Chromatography columns were packed with porous beads, and an axial electric field was applied so that convective buffer flow opposed the direction of electrophoresis of the DNA. A model system composed of approximately equal amounts of the supercoiled and open circular forms of the plasmid pBR 322 (4322 base pairs) was used to test the separation. Chromatography beads (agarose-based) with different porosities were used to determine the effect of the stationary phase on the separation. The porous media did not have a major effect on the separation, but the best separations were obtained using porous chromatography media made with the highest agarose concentration (10% agarose). Selective elution of plasmid DNA with different forms was obtained by either increasing the flow rates or decreasing the electric field strength (by steps or a gradient). in all the separations, the more compact supercoiled form of the plasmid was retained less strongly than either the open circular form (nicked) or the linear form. High molecular weight host genomic DNA was more strongly retained than the plasmid DNA. Increasing the ionic strength of the buffer improved resolution and capacity. The capacity of the separation was determined by injecting increasing amounts of plasmid DNA. Satisfactory separation was obtained at sample loading of up to 360 mu g of total DNA on a column with dimensions of 2.5 by II cm (bed volume of 54 mt). The retention of DNA depends upon a counter-current flow of electrophoresis and convective flow and could be regarded as a type of field flow fractionation. The retention of the DNA by the electric field and flow is discussed in relation to the diffusion coefficients of the DNA. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. Life Technol Inc, Res & Dev, Rockville, MD USA. RP Cole, KD (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 27 TC 9 Z9 9 U1 1 U2 6 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD MAR PY 2000 VL 21 IS 5 BP 1010 EP 1017 DI 10.1002/(SICI)1522-2683(20000301)21:5<1010::AID-ELPS1010>3.3.CO;2-Z PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 300ND UT WOS:000086258300025 PM 10768788 ER PT J AU Beaver, B Sharief, V Teng, Y DeMunshi, R Guo, JP Katondo, E Gallaher, D Bunk, D Grodkowski, J Neta, P AF Beaver, B Sharief, V Teng, Y DeMunshi, R Guo, JP Katondo, E Gallaher, D Bunk, D Grodkowski, J Neta, P TI Development of oxygen scavenger additives for future jet fuels. A role for electron-transfer-initiated oxygenation (ETIO) of 1,2,5-trimethylpyrrole? SO ENERGY & FUELS LA English DT Article ID AUTOXIDATION; OXIDATION; 2,5-DIMETHYLPYRROLE; MECHANISMS; RADICALS; MODEL AB Model autoxidative, radiolytic, and product studies are presented which explore the potential of 1,2,5-trimethylpyrrole (TMP) as an oxygen-scavenger additive for future jet fuels. The oxygenation of TMP in cyclooctane at 120 degrees C is consistent with a mechanism for the initial stages of the reaction being an ETIO reaction. This study provides new insights for the development of oxygen scavengers which may be useful for future jet fuels. C1 Duquesne Univ, Dept Chem & Biochem, Pittsburgh, PA 15282 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Beaver, B (reprint author), Duquesne Univ, Dept Chem & Biochem, Pittsburgh, PA 15282 USA. NR 32 TC 3 Z9 3 U1 0 U2 3 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 MAR-APR PY 2000 VL 14 IS 2 BP 441 EP 447 DI 10.1021/ef990165x PG 7 WC Energy & Fuels; Engineering, Chemical SC Energy & Fuels; Engineering GA 296NW UT WOS:000086031300022 ER PT J AU Van Dolah, FM AF Van Dolah, FM TI Marine algal toxins: Origins, health effects, and their increased occurrence SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Review DE amnesic shellfish poisoning; diarrhetic shellfish poisoning; dinoflagellates; domoic acid; global climate change; harmful algal blooms; marine toxins; neurotoxic shellfish poisoning; okadaic acid; paralytic shellfish poisoning ID SENSITIVE SODIUM-CHANNELS; PRINCE-EDWARD-ISLAND; DOMOIC ACID; SHELLFISH TOXIN; OKADAIC ACID; RAT-BRAIN; PHYTOPLANKTON BLOOMS; TUMOR PROMOTER; IDENTIFICATION; DINOFLAGELLATE AB Certain marine algae produce potent toxins that impact human health through the consumption of contaminated shellfish and finfish and through water or aerosol exposure. Over the past three decades, the frequency and global distribution of toxic algal incidents appear to have increased, and human intoxications from novel algal sources have occurred. This increase is of particular concern, since it parallels recent evidence of large-scale ecologic disturbances that coincide with trends in global warming. The extent to which human activities have contributed to their increase therefore comes into question. This review summarizes the origins and health effects of marine algal toxins, as well as changes in their current global distribution, and examines possible causes for the recent increase in their occurrence. C1 NOAA, Natl Ocean Serv, Marine Biotoxins Program, Ctr Coastal Environm Hlth & Biomol Res, Charleston, SC 29412 USA. RP Van Dolah, FM (reprint author), NOAA, Natl Ocean Serv, Marine Biotoxins Program, Ctr Coastal Environm Hlth & Biomol Res, 219 Ft Johnson Rd, Charleston, SC 29412 USA. EM fran.vandolah@noaa.gov NR 119 TC 350 Z9 364 U1 20 U2 177 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 MAR PY 2000 VL 108 SU 1 BP 133 EP 141 PG 9 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 293MA UT WOS:000085854600013 PM 10698729 ER PT J AU Edmunds, JSG McCarthy, RA Ramsdell, JS AF Edmunds, JSG McCarthy, RA Ramsdell, JS TI Permanent and functional male-to-female sex reversal in d-rR strain medaka (Oryzias latipes) following egg microinjection of o,p '-DDT SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article DE endocrine disrupters; medaka; o,p '-DDT; sex reversal; xenoestrogen ID ESTROGENIC ACTIVITY; RECEPTOR; VITELLOGENESIS; INDUCTION; BINDING; TROUT; DDT; CONTAMINATION; ASSAY; RAT AB Complete sex reversal of fish is accomplished routinely in aquaculture practices by exposing fish to exogenous sex steroids during gonadal differentiation. A variety of environmental chemicals are also active at sex steroid receptors and theoretically possess the potential to alter normal sexual differentiation in fish. However, in controlled environmental chemical exposures to date, only partial alterations of fish sexual phenotype have been observed. Here we report complete, permanent, and functional male-to-female sex reversal in the Japanese medaka (Oryzias latipes, d-rR strain) after a onetime embryonic exposure to the xenoestrogen o,p'-DDT. d-rR strain medaka are strict gonochorists that possesses both sex-linked pigmentation, which distinguishes genotypic sex, and sexually dimorphic external secondary sexual characteristics, which distinguish phenotypic sex. We directly microinjected the xenoestrogen o,p'-DDT into the egg yolks of medaka at fertilization to parallel the maternal transfer of lipophilic contaminants to the embryo. At 10 weeks of age, microinjected medaka were examined for mortality and sex reversal. A calculated embryonic dose of 511 +/- 22 ng/egg o,p'-DDT (mean +/- standard error) resulted in 50% mortality. An embryonic exposure of 227 +/- 22 ng/egg o,p'-DDT resulted in 86% (6 of 7) sex reversal of genetic males to a female phenotype (XY females). XY females were distinguished by sex-linked male pigmentation accompanying female secondary sexual characteristics. Histologic examination of the gonads confirmed active ovaries in 100% of the XY females. In 10-day breeding trials in which XY females were paired with normal XY males, 50% of the XY females produced Fertilized embryos; this represents a comparable breeding success rate to normal XX females. fertilized eggs produced from XY females hatched to viable larvae. These results clearly indicate that a weakly estrogenic pesticide, o,p'-DDT, when presented during the critical period of gonadal development, can profoundly alter sexual differentiation. C1 NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Coastal Res Branch,Marine Biotoxins Program, Charleston, SC 29439 USA. Med Univ S Carolina, Dept Anat & Cell Biol, Charleston, SC 29425 USA. RP Ramsdell, JS (reprint author), NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Coastal Res Branch,Marine Biotoxins Program, 219 Ft Johnson Rd, Charleston, SC 29439 USA. NR 38 TC 65 Z9 74 U1 1 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 MAR PY 2000 VL 108 IS 3 BP 219 EP 224 DI 10.2307/3454437 PG 6 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 296NX UT WOS:000086031400030 PM 10706527 ER PT J AU Whipple, SJ Link, JS Garrison, LP Fogarty, MJ AF Whipple, Stuart J. Link, Jason S. Garrison, Lance P. Fogarty, Michael J. TI Models of predation and fishing mortality in aquatic ecosystems SO FISH AND FISHERIES LA English DT Article DE aquatic ecosystems; ecological model; fishery management; food web; predation; simulation AB The dynamics of fish stocks are greatly influenced by predatory and fishery removals. We describe the strengths and weaknesses of a suite of approaches that assess the scope and magnitude of fishery and predatory mortality in aquatic ecosystems. We examine: (i) empirical models for pattern detection, process exploration, and model parameterization (e.g. multispecies time series and multiple regression); (ii) qualitative process-based models of species interactions (e.g. food web analyses and loop analyses); and quantitative process-based multispecies models that include: (iii) static flow models (e.g. ECOPATH); (iv) dynamic models of either numerical abundance (e.g. Lotka-Volterra) or biomass (e.g. ECOSIM and multispecies biomass dynamics); and (v) spatially explicit versions of the above. Decisions concerning a specific modelling approach should be evaluated in the context of the goals of the model and empirical database. Important considerations include model use, desired output, and management context. Four important factors to consider in model selection are the spatial and temporal extent and resolution, conservation of mass or numbers, mathematical representation of predator prey interactions, and mathematical representation of technical interactions. We conclude that the most effective modelling exercise to achieve a given set of goals should incorporate the evaluation of multiple model configurations. C1 [Whipple, Stuart J.; Link, Jason S.; Garrison, Lance P.; Fogarty, Michael J.] NMFS NEFSC, Food Web Dynam Program, Woods Hole, MA 02536 USA. RP Whipple, SJ (reprint author), NMFS NEFSC, Food Web Dynam Program, 166 Water St, Woods Hole, MA 02536 USA. EM stuart.whipple@noaa.gov FU National Research Council postdoctoral research associateships at the NEFSC FX We thank Wendy Gabriel, Jon Brodziak, Deborah Hart, John Boreman, and three anonymous referees for comments and suggestions that improved this paper. We thank Jackie Riley of the NMES Library and staff of the MBL/WHOI Library for assistance in locating references. SJW and LPG were supported by National Research Council postdoctoral research associateships at the NEFSC. NR 79 TC 80 Z9 82 U1 0 U2 11 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1467-2960 EI 1467-2979 J9 FISH FISH JI Fish. Fish. PD MAR PY 2000 VL 1 IS 1 BP 22 EP 40 DI 10.1046/j.1467-2979.2000.00007.x PG 19 WC Fisheries SC Fisheries GA V33AY UT WOS:000208992900004 ER PT J AU Cole, J AF Cole, J TI Coastal sea surface temperature and coho salmon production off the north-west United States SO FISHERIES OCEANOGRAPHY LA English DT Article DE California current; coho salmon; marine survival; remote sensing; sea surface temperature; upwelling ID ONCORHYNCHUS-KISUTCH; SATELLITE IMAGERY; OREGON; VARIABILITY; RECRUITMENT; WASHINGTON; ABUNDANCE; SURVIVAL; WINDOW AB A time Series of mean weekly sea surface temperature (SST) images was used to investigate the relationship between fluctuations in the marine survival of hatchery-reared coho salmon and coastal ocean dynamics off the north-western United States (51 degrees to 37 degrees N) between 1985 and 1996, using univariate and nonlinear bivariate regression analysis. Ocean conditions were matched against survival for a number of different annual time frames according to the sum of negative or positive weekly SST anomalies. From the univariate analyses, the sum of negative anomalies from April to June, when the juvenile salmon first enter the ocean, was found to have an R-2 of 0.88 against survival with 1991 excluded as an outlier. The bivariate multiple regressions used the sum of negative anomalies from April to lune as the first independent variable. When the sums of positive anomalies from the following periods during the fishes' second calendar year in the ocean were each used as the second independent variable, the R-2 Values were all greater than or equal to 0.92 (with no data points excluded): January to June, February to lune, April to June, March to lune. These results are discussed within the context of coastal ocean processes. It is concluded that the analysis of SST image time series might allow management to make reasonable forecasts of hatchery-reared coho salmon survival. C1 NOAA, NMFS, Pacific Fisheries Environm Lab, Pacific Grove, CA 93950 USA. RP Cole, J (reprint author), NOAA, NMFS, Pacific Fisheries Environm Lab, Pacific Grove, CA 93950 USA. NR 33 TC 40 Z9 42 U1 1 U2 1 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD MAR PY 2000 VL 9 IS 1 BP 1 EP 16 DI 10.1046/j.1365-2419.2000.00118.x PG 16 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 323FK UT WOS:000087552000001 ER PT J AU Polovina, JJ Kobayashi, DR Parker, DM Seki, MP Balazs, GH AF Polovina, JJ Kobayashi, DR Parker, DM Seki, MP Balazs, GH TI Turtles on the edge: movement of loggerhead turtles (Caretta caretta) along oceanic fronts, spanning longline fishing grounds in the central North Pacific, 1997-1998 SO FISHERIES OCEANOGRAPHY LA English DT Article DE Caretta caretta; central North Pacific; loggerhead turtles; longline fishery; satellite remote sensing; subtropical front ID SEAWIFS; HAWAII AB Nine juvenile loggerhead sea turtles tracked during 1997 and 1998 in the central North Pacific by satellite telemetry all travelled westward, against prevailing currents, along two convergent fronts identified by satellite remotely sensed data on sea surface temperature (SST), chlorophyll and geostrophic currents. These fronts are characterized by gradients in sea surface height that produce an eastward geostrophic current, with gradients in surface chlorophyll and SST. Six of the turtles were associated with a front characterized by 17 degrees C SST, surface chlorophyll of about 0.2 mg m(-3), and eastward geostrophic current of about 4 cm s(-1), while the other three turtles were associated with a front with 20 degrees C SST, surface chlorophyll of about 0.1 mg m(-3), and eastward geostrophic flow of about 7 cm s(-1). These results appear to explain why incidental catch rates of loggerheads in the Hawaii longline fishery are highest when gear is set at 17 degrees C and 20 degrees C, SST. Further, from the seasonal distribution of longline effort relative to these fronts, it appears that the surface longline fishing ground lies largely between these two fronts during the first quarter and well to the south of the 17 degrees C front, but including the 20 degrees C front, in the second quarter. These findings suggest seasonal or area closures of the longline fishery that could be tested to reduce incidental catches of loggerheads. Finally, these results illustrate the insights which can be achieved by combining data on movement of pelagic animals with concurrent remotely sensed environmental data. C1 Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, NOAA, Honolulu, HI 96822 USA. Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. RP Polovina, JJ (reprint author), Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, NOAA, 2570 Dole St, Honolulu, HI 96822 USA. NR 21 TC 158 Z9 169 U1 1 U2 24 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD MAR PY 2000 VL 9 IS 1 BP 71 EP 82 DI 10.1046/j.1365-2419.2000.00123.x PG 12 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 323FK UT WOS:000087552000006 ER PT J AU Morgan, LE Wing, SR Botsford, LW Lundquist, CJ Diehl, JM AF Morgan, LE Wing, SR Botsford, LW Lundquist, CJ Diehl, JM TI Spatial variability in red sea urchin (Strongylocentrotus franciscanus) recruitment in northern California SO FISHERIES OCEANOGRAPHY LA English DT Article DE Larval dispersal; meroplankton; northern California; recruitment varia; red sea urchin; spine canopy; Strongylocentrotus franciscanus; upwelling relaxation ID OCEAN DYNAMICS EXPERIMENT; CROSS-SHELF TRANSPORT; LARVAL DISPERSAL; BENTHIC INVERTEBRATES; FISHERIES MANAGEMENT; PURPURATUS STIMPSON; POPULATION-DYNAMICS; MARINE INVERTEBRATE; INTERTIDAL BARNACLE; UPWELLING SHADOWS AB To better understand the spatial distribution of recruitment in the northern California red sea urchin (Strongylocentrotus franciscanus) population, we sampled size distributions at each of 12 locations in 1995 and 1996, two of those locations in 1994, and 5 of those locations in 1997. An index of recent recruitment in these size distributions and an estimate of density of recent recruitment reflect a similar spatial pattern of recruitment. This pattern appears to be determined by the effect of coastal circulation on larval delivery during relaxation of upwelling, and not the result of the positive effect of the adult spine canopy on juvenile survival. Recent recruitment of red sea urchins in northern California is higher in areas more frequently subjected to onshore and poleward flow during relaxation of upwelling. These results are consistent with a mechanism by which alongshore spatial variability in southward, offshore flow during upwelling winds allows larvae to maintain latitudinal position, whereas flows during event-scale relaxations in upwelling winds serve to distribute settling larvae alongshore, favouring areas north of promontories. The consequent spatial pattern of red sea urchin settlement varies from year to year, and there are not yet sufficient data to demonstrate the degree to which this spatial pattern in recruitment determines a spatial pattern in fishable adult abundance. C1 Univ Calif Davis, Dept Wildlife Fish & Conservat Biol, Davis, CA 95616 USA. Univ Otago, Dept Marine Sci, Dunedin, New Zealand. RP Morgan, LE (reprint author), NMFS, SWFSC, Santa Cruz Tiburon Lab, 3150 Paradise Dr, Tiburon, CA 94920 USA. RI Lundquist, Carolyn/C-1716-2009 NR 88 TC 42 Z9 42 U1 1 U2 7 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD MAR PY 2000 VL 9 IS 1 BP 83 EP 98 DI 10.1046/j.1365-2419.2000.00124.x PG 16 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 323FK UT WOS:000087552000007 ER PT J AU Ryer, CH Olla, BL AF Ryer, CH Olla, BL TI Avoidance of an approaching net by juvenile walleye pollock Theragra chalcogramma in the laboratory: the influence of light intensity SO FISHERIES RESEARCH LA English DT Article DE fish behavior; fishing gear; illumination; bycatch; gear selectivity; stress; walleye pollock; Theragra chalcogramma ID FISH; GEAR AB Fisheries management strategies often rely upon regulation of mesh sizes or the use of exclusion/escape structures to reduce the bycatch of undersize fish or non-target species. Design and evaluation of fishing gears to reduce bycatch should be based upon knowledge of fish behavior and sensory capabilities. The response of juvenile walleye pollock Theragra chalcogramma to an approaching panel made of 8 cm square mesh netting was compared under a range of laboratory illuminations, from <1 x 10(-8) (darkness) to 1.7 x 10(-3) mu moles photons m(-2)s(-1). Fish in darkness struck the net more frequently and swam closer to the net than fish at the highest illumination. These results, along with those of other laboratory and field studies, suggest that trawl bycatch reduction strategies which rely upon undersize or non-target fish using vision to guide them out of the net may be less effective at night or at depths where ambient light levels fall below critical levels. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr,Fisheries Behav Ecol Pro, Newport, OR 97365 USA. RP Ryer, CH (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr,Fisheries Behav Ecol Pro, Newport, OR 97365 USA. NR 12 TC 24 Z9 25 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD MAR PY 2000 VL 45 IS 2 BP 195 EP 199 DI 10.1016/S0165-7836(99)00113-7 PG 5 WC Fisheries SC Fisheries GA 295VC UT WOS:000085987700009 ER PT J AU Baker, DJ Ewins, PD AF Baker, DJ Ewins, PD TI Basic science of global warming has not changed SO FORESTRY CHRONICLE LA English DT News Item C1 US Natl Ocean & Atmospher Adm, Washington, DC USA. RP Baker, DJ (reprint author), US Natl Ocean & Atmospher Adm, Washington, DC USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU CANADIAN INST FORESTRY PI OTTAWA PA 151 SLATER ST, STE 606, OTTAWA, ONTARIO K1P 5H3, CANADA SN 0015-7546 J9 FOREST CHRON JI For. Chron. PD MAR-APR PY 2000 VL 76 IS 2 BP 219 EP 219 PG 1 WC Forestry SC Forestry GA 313MW UT WOS:000087004300013 ER PT J AU Dalluge, JJ AF Dalluge, JJ TI Mass spectrometry for direct determination of proteins in cells: applications in biotechnology and microbiology SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Review ID ASSISTED-LASER-DESORPTION/IONIZATION; COMPLEX BIOLOGICAL SAMPLES; DESORPTION IONIZATION; RAPID IDENTIFICATION; MALDI-MS; ELECTROSPRAY-IONIZATION; WHOLE CELLS; DUAL MICRODIALYSIS; E-COLI; BACTERIA AB A number of different procedures have been developed in recent years that utilize mass spectrometry for the direct determination of proteins in complex mixtures of biological origin. Specific examples of these include the use of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) or directly combined liquid chromatography-electrospray ionization mass spectrometry (LC/ESI-MS) for rapid profiling of protein expression in bacterial and eucaryotic cells and cell-free extracts. Approaches to sample cleanup, contaminant removal, and initial separation of analytes on-line for the direct determination of proteins in cells using MALDI- and ESI-MS are discussed. Advantages of these techniques over traditional biochemical methods are highlighted, and a critical review of their utility and potential as standard tools in the biomolecular and microbiological research laboratory is presented. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Dalluge, JJ (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. EM joseph.dalluge@nist.gov NR 51 TC 39 Z9 41 U1 1 U2 7 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD MAR-APR PY 2000 VL 366 IS 6-7 BP 701 EP 711 DI 10.1007/s002160051564 PG 11 WC Chemistry, Analytical SC Chemistry GA 307PG UT WOS:000086661300019 PM 11225781 ER PT J AU Chi, PJ Russell, CT Musman, S Peterson, WK Le, G Angelopoulos, V Reeves, GD Moldwin, MB Chun, FK AF Chi, PJ Russell, CT Musman, S Peterson, WK Le, G Angelopoulos, V Reeves, GD Moldwin, MB Chun, FK TI Plasmaspheric depletion and refilling associated with the September 25, 1998 magnetic storm observed by ground magnetometers at L=2 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FIELD LINES; RESONANCE; DENSITY AB The plasmaspheric mass density at L similar or equal to 2 was monitored by two IGPP/LANL ground magnetometer stations during the magnetic storm on September 25, 1998. Even at this low latitude the plasma density dropped significantly to similar or equal to 1/4 of the pre-storm value. The total electron content (TEC) inferred by GPS signals also shows a sizable decrease during the storm. The observations suggest that the convection caused by the strong electric field associated with the magnetic storm eroded the plasmasphere as low as L = 2, which is a much lower latitude than that expected from the estimated potential drop across the polar cap together with a simple model of the magnetospheric convection pattern. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. NOAA, Geosci Res Div, Silver Spring, MD 20910 USA. Lockheed Martin Space Sci Lab, Dept H111, Palo Alto, CA 94304 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA. USAF Acad, Dept Phys, Colorado Springs, CO 80840 USA. RP Chi, PJ (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RI Moldwin, Mark/F-8785-2011; Le, Guan/C-9524-2012; Peterson, WK/A-8706-2009; Reeves, Geoffrey/E-8101-2011; OI Moldwin, Mark/0000-0003-0954-1770; Le, Guan/0000-0002-9504-5214; Peterson, WK/0000-0002-1513-6096; Reeves, Geoffrey/0000-0002-7985-8098; Russell, Christopher/0000-0003-1639-8298 NR 14 TC 44 Z9 45 U1 0 U2 3 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 MAR 1 PY 2000 VL 27 IS 5 BP 633 EP 636 DI 10.1029/1999GL010722 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 288YJ UT WOS:000085591800013 ER PT J AU Karl, TR Knight, RW Baker, B AF Karl, TR Knight, RW Baker, B TI The record breaking global temperatures of 1997 and 1998: Evidence for an increase in the rate of global warming? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TIME-SERIES AB During the time between May of 1997 and September of 1998, for sixteen consecutive months, each month broke the previous monthly all-rime record high temperature. Using autoregressive intervention moving average (ARMA) models in a series of Monte Carlo experiments the probability of such an event was analyzed for various rates of temperature change. The string of record-breaking global temperatures could not be readily explained by the best fit linear increase of temperature since the late 1970's (2 degrees C/Century), although the event was not implausible (probabilities slightly less than 5%). The 1997-98 event could signal yet another change point in the rate of global temperature increase, but the warming rate over the past few decades is already comparable to that projected during the 21st Century based on IPCC business as usual scenarios of anthropogenic climate change (Kattenberg ct al., 1996). C1 NOAA, Natl Climat Date Ctr, Asheville, NC 28801 USA. RP Karl, TR (reprint author), NOAA, Natl Climat Date Ctr, 151 Patton Ave,Rm 120, Asheville, NC 28801 USA. NR 15 TC 78 Z9 84 U1 1 U2 5 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 MAR 1 PY 2000 VL 27 IS 5 BP 719 EP 722 DI 10.1029/1999GL010877 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 288YJ UT WOS:000085591800035 ER PT J AU Bond, NA Harrison, DE AF Bond, NA Harrison, DE TI The Pacific Decadal Oscillation, air-sea interaction and central north Pacific winter atmospheric regimes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SST ANOMALIES; EL-NINO; VARIABILITY; CIRCULATION; DYNAMICS; PATTERN AB Prominent and persistent anomalies in the atmospheric flow (troughs and ridges) occur sporadically over the central North Pacific, and can have profound consequences for the weather of North America. We have examined how these events are associated with large scale central North Pacific sea surface temperature (SST) anomalies, using an index for the Pacific Decadal Oscillation (PDO). The anomalies in turbulent air-sea heat fluxes and low-level baroclinity associated with the PDO are manifested differently during troughs than during ridges in their effects on the transient eddies (storms). These effects may help explain why prominent troughs (ridges) occur about 3 (2.5) times more frequently during periods when the PDO is significantly positive (negative) than of opposite sign. Our results suggest that the state of the mid-latitude Pacific Ocean more fundamentally affects the atmosphere than has been thought. C1 Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Bond, NA (reprint author), Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RI Harrison, Don/D-9582-2013 NR 14 TC 60 Z9 68 U1 0 U2 20 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 MAR 1 PY 2000 VL 27 IS 5 BP 731 EP 734 DI 10.1029/1999GL010847 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 288YJ UT WOS:000085591800038 ER PT J AU Murnane, RJ Sarmiento, JL AF Murnane, RJ Sarmiento, JL TI Roles of biology and gas exchange in determining the delta C-13 distribution in the ocean and the preindustrial gradient in atmospheric delta C-13 SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID ACID DISSOCIATION-CONSTANTS; GENERAL-CIRCULATION MODEL; PAST 2 CENTURIES; FOSSIL-FUEL CO2; WORLD OCEAN; CARBON-DIOXIDE; ISOTOPIC COMPOSITION; C-13/C-12 RATIO; C-13; SEAWATER AB We examine the processes responsible for the distribution of delta(13)C in a global ocean model. The dominant sources of gradients are biological processes and the temperature effect on isotopic fractionation. However, in a model without biology developed to examine the temperature effect of isotopic fractionation in isolation, we find an almost uniform delta(13)C distribution. Extremely slow delta(13)C air-sea equilibration does not permit the surface ocean to come into equilibrium with the atmosphere and delta(13)C in the ocean thus becomes well mixed. However biological effects, which are interior to the ocean, are strongly expressed and minimally effected by air-sea exchange. Biological fractionation thus dominates the oceanic delta(13)C distribution. An important feature of the model is an extremely large northward transport of isotopic anomaly. The transfer from the ocean to the Northern Hemisphere atmosphere of 120 Pg C parts per thousand is equivalent in magnitude to the signal that would be generated by a net terrestrial biospheric uptake of approximate to 5 Pg C yr(-1) from the Northern Hemisphere atmosphere, or an approximate to 1-2 parts per thousand disequilibrium between terrestrial respiration and photosynthesis. Improved ocean model simulations and observational analysis are required to test for the possible existence of such a large oceanic transport of isotopic anomaly. C1 Bermuda Biol Stn Res, Risk Predict Initiat, Ferry Reach GE01, St Georges, Bermuda. Princeton Univ, Dept Geosci, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Murnane, RJ (reprint author), Bermuda Biol Stn Res, Risk Predict Initiat, Ferry Reach GE01, St Georges, Bermuda. EM rmurnane@bbsr.edu NR 62 TC 7 Z9 7 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 EI 1944-9224 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD MAR PY 2000 VL 14 IS 1 BP 389 EP 405 DI 10.1029/1998GB001071 PG 17 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 292RM UT WOS:000085808900029 ER PT J AU Gloor, M Fan, SM Pacala, S Sarmiento, J AF Gloor, M Fan, SM Pacala, S Sarmiento, J TI Optimal sampling of the atmosphere for purpose of inverse modeling: A model study SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID CO2 AB The 66 stations of the GLOBALVIEW-CO2 sampling network (GLOBALVIEW-CO2: Cooperative Atmospheric Data Integration Project Carbon Dioxide, (1997)) are located primarily remotely from continents where signals of fossil fuel consumption and biospheric exchange are diluted. It is thus not surprising that inversion studies are able to estimate terrestrial sources and sinks only to a very limited extent. The poor constraint on terrestrial fluxes propagates to the oceans and strongly limits estimates of oceanic fluxes as well, at least if no use is made of other information such as isotopic ratios. We analyze here the resolving power of the GLOBALVIEW-CO2 network, compare the efficiency of different measurement strategies, and determine optimal extensions to the present network. We find the following: (1) GLOBALVIEW-CO2 is well suited to characterize the meridional distribution of sources and sinks but is poorly suited to separate terrestrial from oceanic sinks at the same latitude. The most poorly constrained regions are South America, Africa, and southern hemispheric oceans. (2) To improve the network, observing stations need to be positioned on the continents near to the largest biospheric signals despite the large diurnal and seasonal fluctuations associated with biological activity and the dynamics of the PBL, The mixing in the atmosphere is too strong to allow positioning of stations remote from large fluxes, Our optimization results prove to be fairly insensitive to the details of model transport and the inversion model with the addition of similar to 10 optimally positioned stations. (3) The best measurement strategy among surface observations, N-S airplane transects, and vertical profiles proves to be vertical profiles. (4) Approximately 12 optimally positioned vertical profiles or 30 surface stations in addition to GLOBALVIEW-CO2 would reduce estimate uncertainties caused by insufficient data coverage from similar to 1 Pg C yr(-1) per region to similar to 0.2 Pg C yr(-1) per region. C1 Princeton Univ, Dept Ecol & Evolutionary Biol, Princeton, NJ 08544 USA. Princeton Univ, Atmospher & Ocean Sci Program, Carbon Modeling Consortium, Princeton, NJ 08544 USA. RP Gloor, M (reprint author), Max Planck Inst Biogeochem, Postfach 100164, D-07701 Jena, Germany. NR 16 TC 68 Z9 71 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD MAR PY 2000 VL 14 IS 1 BP 407 EP 428 DI 10.1029/1999GB900052 PG 22 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 292RM UT WOS:000085808900030 ER PT J AU Suntharalingam, P Sarmiento, JL AF Suntharalingam, P Sarmiento, JL TI Factors governing the oceanic nitrous oxide distribution: Simulations with an ocean general circulation model SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID PACIFIC-OCEAN; WORLD OCEAN; OXYGEN MINIMUM; NORTH-ATLANTIC; TRACE GASES; ARABIAN SEA; EL-NINO; N2O; NITRIFICATION; DENITRIFICATION AB A global model of the oceanic nitrous oxide distribution is developed to evaluate current understanding of the processes governing nitrous oxide formation and distribution in the open ocean. N(2)O is treated as a nonconserved tracer in a global ocean general circulation model subject to biological sources in the oceanic interior and gas exchange at the ocean surface. A simple scalar parameterization linking N(2)O production to oxygen consumption land based on observed correlations between excess N(2)O and apparent oxygen utilization) is successful in reproducing the large-scale features of the observed distribution, namely, high surface supersaturations in regions of upwelling and biological productivity, and values close to equilibrium in the oligotrophic subtropical gyres. The majority of the oceanic N(2)O source is produced in the upper water column lover 75% above 600 m) and effluxes directly to the atmosphere in the latitude band of formation. The observed structure at depth is not as well reproduced by this model, which displays excessive N(2)O production in the deep ocean. An alternative source parameterization, which accounts for processes which result in a depth variation in the relationship between N(2)O production and oxygen consumption, yields an improved representation of the deep distribution. The surface distribution and sea-air flux are, however, determined primarily by the upper ocean source and, therefore, are relatively insensitive to changes in the nature of deep oceanic N(2)O production. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Suntharalingam, P (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 20 Oxford St, Cambridge, MA 02138 USA. EM pns@europa.harvard.edu NR 82 TC 59 Z9 65 U1 7 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD MAR PY 2000 VL 14 IS 1 BP 429 EP 454 DI 10.1029/1999GB900032 PG 26 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 292RM UT WOS:000085808900031 ER PT J AU Rodo, X Comin, FA AF Rodo, X Comin, FA TI Links between large-scale anomalies, rainfall and wine quality in the Iberian Peninsula during the last three decades SO GLOBAL CHANGE BIOLOGY LA English DT Article DE ENSO; Iberian Peninsula; La Rioja; NAO; Rainfall anomalies; wine ID NORTH-ATLANTIC OSCILLATION; NINO SOUTHERN OSCILLATION; EL-NINO; SEASONAL RAINFALL; PRECIPITATION; TEMPERATURE; VARIABILITY; CIRCULATION; PREDICTION; TRENDS AB Recent strong El Nino-Southern Oscillation (ENSO) signals have been identified in precipitation records from the Iberian Peninsula. Interannual association with ENSO accounts for more than half the total annual variance in selected stations of the south-east, with ENSO leading rainfall by one year. In contrast, association with the North Atlantic Oscillation (NAO) at the Westernmost stations is much lower (25%). The potential of simple linear models is tested in the ENSO-sensitive area, suggesting high capability of the Southern Oscillation Index (SOI) for predicting interannual rainfall fluctuations (mainly droughts and floods). Wine quality is associated with several factors, e.g. grape variety, soil type and processing, which can be considered invariable, mainly due to the strict regulations imposed by the quality regulating councils. Climate, however, has a great influence on resulting wine quality, and represents the most important source of variability at both short (day-to-day) and long (interannual) time scales. Over the last 30 years, high-quality harvests in the five main wine regions in Spain, show a high probability (P < 0.0002) of being associated with an El Nino event occurring the same year or the year before. NAO influence is not significant during the same period. Thus, apart from considering the role of local climatic conditions in certain regions, which favour the production of excellent wines, larger-scale climatic phenomena appear responsible for the year-to-year variations in quality. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Rodo, X (reprint author), Univ Barcelona, Fac Biol, Dept Ecol, Climate Impact Anal Grp, Barcelona, Spain. OI Rodo, Xavier/0000-0003-4843-6180 NR 34 TC 21 Z9 22 U1 1 U2 8 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1354-1013 J9 GLOB CHANGE BIOL JI Glob. Change Biol. PD MAR PY 2000 VL 6 IS 3 BP 267 EP 273 DI 10.1046/j.1365-2486.2000.00299.x PG 7 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 299KQ UT WOS:000086198100002 ER PT J AU Ozgur, M Zaghloul, ME Gaitan, M AF Ozgur, M Zaghloul, ME Gaitan, M TI Micromachined 28-GHz power divider in CMOS technology SO IEEE MICROWAVE AND GUIDED WAVE LETTERS LA English DT Article DE CMOS micromachining; coupled coplanar transmission lines; power divider AB A broad-band power divider is presented in CMOS technology. The devices are realized by postprocessing chips that are fabricated in a standard 1.2-mu m CMOS process. Developed postprocessing includes wire bonding for ground equalization, deposition of a stress-compensation layer, and selective etching of the silicon substrate. By employing coupled coplanar transmission lines, the area of dividers is minimized to 0.8 mm x 2.1 mm. A 20-35-GHz power divider exhibits a coupling of -3.8 dB +/- 0.6 dB. C1 George Washington Univ, Dept Elect & Comp Engn, Washington, DC 20052 USA. Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Ozgur, M (reprint author), George Washington Univ, Dept Elect & Comp Engn, Washington, DC 20052 USA. NR 12 TC 6 Z9 6 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 1051-8207 J9 IEEE MICROW GUIDED W JI IEEE Microw. Guided Wave Lett. PD MAR PY 2000 VL 10 IS 3 BP 99 EP 101 DI 10.1109/75.845710 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 323DU UT WOS:000087550200005 ER PT J AU Little, BE Chu, ST Pan, W Kokubun, Y AF Little, BE Chu, ST Pan, W Kokubun, Y TI Microring resonator arrays for VLSI photonics SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE microresonator; wavelength-division multiplexing (WDM); wavelength filter ID CHANNEL DROPPING FILTERS AB The analytic theory governing the complete scattering response of two-dimensional (2-D) microring resonator arrays is developed. The method is applicable to arbitrary interconnections of general four-port, single polarization nodes. An 8 x 8 cross-grid array of vertically coupled glass microring resonators is fabricated for test purposes. C1 MIT, Elect Res Lab, Cambridge, MA 02139 USA. Univ Maryland, Phys Sci Lab, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Kanagawa Acad Sci & Technol, Kawasaki, Kanagawa 2130012, Japan. RP Little, BE (reprint author), MIT, Elect Res Lab, 77 Massachusetts Ave, Cambridge, MA 02139 USA. RI Pan, Wugen/A-8627-2011; Chu, Sai /D-3312-2014; Kokubun, Yasuo/N-1500-2014; OI Kokubun, Yasuo/0000-0002-3448-4870; CHU, Sai Tak /0000-0001-8263-8507 NR 11 TC 157 Z9 160 U1 2 U2 20 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAR PY 2000 VL 12 IS 3 BP 323 EP 325 DI 10.1109/68.826928 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 297DZ UT WOS:000086067700033 ER PT J AU Vogel, EM Henson, WK Richter, CA Suehle, JS AF Vogel, EM Henson, WK Richter, CA Suehle, JS TI Limitations of conductance to the measurement of the interface state density of MOS capacitors with tunneling gate dielectrics SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE capacitance; conductance; dielectric films; MOS devices; tunneling ID INVERSION LAYER; QUANTIZATION; MODEL; ELECTRON AB A systematic study of the uncertainties, sensitivity and limitations of the conductance technique for extracting the interface state density of tunneling dielectrics is presented. The methodology required to extract device parameters and interface state density from conductance and capacitance data is reviewed and analyzed. The effect of uncertainties in device parameters on extracted interface state density was determined using experimental results of thin oxides (1.4 nm and 2.0 nm). Modeling was used to indicate the effects of various device parameters on the sensitivity of conductance to changes in interface state density. The effect of uncertainties in insulator capacitance of equivalently thin dielectrics on uncertainties in extracted interface state density is minimal. The effect of uncertainties in series resistance increases with increasing bias towards accumulation. An increase in the series resistance of the device causes reduced sensitivity to changes in interface state density especially for interface states located nearer the majority band edge, Increasing tunneling current causes increased uncertainties and reduced sensitivity to changes in interface state density especially for interface states nearer midgap. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. N Carolina State Univ, Dept Elect & Comp Engn, Raleigh, NC 27695 USA. RP Vogel, EM (reprint author), Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RI Vogel, Eric/A-7731-2008 OI Vogel, Eric/0000-0002-6110-1361 NR 33 TC 78 Z9 78 U1 0 U2 16 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 MAR PY 2000 VL 47 IS 3 BP 601 EP 608 DI 10.1109/16.824736 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 291YA UT WOS:000085766300016 ER PT J AU Wick, GA Bates, JJ Gottschall, CC AF Wick, GA Bates, JJ Gottschall, CC TI Observational evidence of a wind direction signal in SSM/I passive microwave data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE microwave radiometry; ocean surface winds; SSM/I ID SURFACE BRIGHTNESS TEMPERATURES; AIRCRAFT K-BAND; WATER; EMISSION; RADIOMETERS; RETRIEVAL; IMAGER AB Recent experiments have demonstrated that a wind direction signal is apparent in passive microwave brightness temperature measurements of the sea surface. Extensive matches of Special Sensor Microwave Imager (SSM/I) brightness temperatures from several Defense Meteorological Satellite Program (DMSP) satellites with wind direction measurements from both moored buoys and spaceborne scatterometers clearly show directional signals at 19, 37, and 85 GHz for both horizontal and vertical polarization. The wind direction signal obtained from the mooring matches is noisy due to the limited number of matches but varies little from satellite to satellite, The greater number of matches with the scatterometers results in a clearer directional signal and enables detailed studies of the dependence of the directional signal on environmental conditions. The amplitude of the mean directional signal increases with wind speed. The up/downwind asymmetry most prominent at vertical polarization varies mainly with wind speed, while the crosswind differences also vary with sea state and sea surface temperature. The variability about the mean directional signal is equal to or greater than the amplitude of the mean signal and increases with increasing water vapor content. Because of the large variability, large numbers of SSM/I observations under similar environmental conditions must be averaged before the directional signal is apparent. Comparisons between the observed directional signals and existing model predictions will lend insight into the physical mechanisms responsible for the signal. C1 Univ Colorado, CDC, CIRES, Boulder, CO 80309 USA. NOAA, Environm Technol Lab, Boulder, CO 80309 USA. RP Wick, GA (reprint author), Univ Colorado, CDC, CIRES, Boulder, CO 80309 USA. RI Bates, John/D-1012-2009 OI Bates, John/0000-0002-8124-0406 NR 24 TC 17 Z9 20 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 2000 VL 38 IS 2 BP 823 EP 837 DI 10.1109/36.842011 PN 1 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 304TF UT WOS:000086499700020 ER PT J AU Zavorotny, VU Voronovich, AG AF Zavorotny, VU Voronovich, AG TI Scattering of GPS signals from the ocean with wind remote sensing application SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE bistatic rough surface scattering; sea surface remote sensing ID ROUGH-SURFACE; SEA-SURFACE; SYSTEM; WAVES; SLOPE AB A theoretical model that describes the power of a scattered Global Positioning System (GPS) signal as a function of geometrical and environmental parameters has been developed. This model is based on a bistatic radar equation derived using the geometric optics limit of the Kirchhoff approximation, The waveform (i.e., the time-delayed power obtained in the delay-mapping technique) depends on a wave-slope probability density function, which in turn depends on wind. Waveforms obtained for aircraft altitudes and velocities indicate that altitudes within the interval 5-15 kin are the best for inferring mind speed. In some regimes, an analytical solution for the bistatic radar equation is possible. This solution allows converting trailing edges of waveforms into a set of straight lines, which could be convenient for mind retrieval. A transition to satellite altitudes, together with satellite velocities, makes the peak power reduction and the Doppler spreading effect a significant problem for wind retrieval based on the delay-mapping technique. At the same time, different time delays and different Doppler shifts of the scattered GPS signal could form relatively small spatial cells on sea surface, suggesting mapping of the wave-slope probability distribution in a synthetic-aperture-radar (SAR) fashion. This may allow more accurate measurements of wind velocity and wind direction. C1 Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NR 34 TC 306 Z9 346 U1 6 U2 29 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 2000 VL 38 IS 2 BP 951 EP 964 DI 10.1109/36.841977 PN 2 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 304TG UT WOS:000086499800006 ER PT J AU Walls, FL AF Walls, FL TI Correlation between upper and lower sidebands SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article; Proceedings Paper CT Joint Meeting of the European-Frequency-and-Time-Forum/IEEE International Frequency Control Symposium CY APR 13-16, 1999 CL BESANCON, FRANCE SP Soc Francaise Microtechn & Chronometrie, IEEE ID AM NOISE AB Experimental measurements supported by a simple model show that the upper and lower phase modulation (PM) noise sidebands are always equal and 100% correlated, independent of the noise power originating from multiplicative or additive processes [1]. Similarly, we show that the upper and lower amplitude modulation (AM) noise sidebands are also equal and 100% correlated, independent of the noise power originating from multiplicative or additive processes. Moreover, the single sideband (SSB) PM noise is always equal to one-half the total PM noise. The same is true for the AM noise. Although the upper and lower PM or AM noise sidebands are equal and correlated for broadband additive noise, the phase between the AM and the PM sidebands varies randomly with time. These conclusions still hold even when the RF noise sidebands are not symmetric about the carrier. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Walls, FL (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 4 TC 11 Z9 11 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 2000 VL 47 IS 2 BP 407 EP 410 DI 10.1109/58.827427 PG 4 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 294TL UT WOS:000085926400013 PM 18238557 ER PT J AU Sen Gupta, A Popovic, D Walls, FL AF Sen Gupta, A Popovic, D Walls, FL TI Cs frequency synthesis: A new approach SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article; Proceedings Paper CT Joint Meeting of the European-Frequency-and-Time-Forum/IEEE International Frequency Control Symposium CY APR 13-16, 1999 CL BESANCON, FRANCE SP Soc Francaise Microtechn & Chronometrie, IEEE ID STANDARD AB This paper describes a new approach to synthesizing the Cs hyperfine frequency of 9.192 GHz that is designed to be sufficiently rugged for use in space, specifically for the Primary Atomic Reference Clock in Space (PARCS) planned for the International Space Station, as well as ground applications. This new approach requires no narrow band filters or frequency multiplication, and the primary source of cooling is conduction. Instead of frequency multiplication, it uses a custom regenerative divider stage followed by two commercial binary dividers and several mixing stages. A fractional frequency step of 2 x 10(-17) is achieved by mixing the output of a 48-bit numerically controlled oscillator with the microwave signal. Preliminary tests on the new synthesizer design indicate an internal fractional frequency stability of 1 x 10(-15) at 10 s and 1 x 10(-18) at 1 d, dominated by the daily room temperature variations. The phase and amplitude noise are similar to our previous designs that used frequency multiplication and narrow band filters. The temperature coefficient is less than 0.2 ps/K. C1 Natl Phys Lab, New Delhi 110012, India. Univ Belgrade, YU-11001 Belgrade, Yugoslavia. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Sen Gupta, A (reprint author), Natl Phys Lab, Dr Krishnan Rd, New Delhi 110012, India. EM sengupta@csnpl.ren.nic.in NR 10 TC 13 Z9 13 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 2000 VL 47 IS 2 BP 475 EP 479 DI 10.1109/58.827439 PG 5 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 294TL UT WOS:000085926400025 PM 18238569 ER PT J AU Larson, KM Levine, J Nelson, LM Parker, TE AF Larson, KM Levine, J Nelson, LM Parker, TE TI Assessment of GPS carrier-phase stability for time-transfer applications SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article; Proceedings Paper CT Joint Meeting of the European-Frequency-and-Time-Forum/IEEE International Frequency Control Symposium CY APR 13-16, 1999 CL BESANCON, FRANCE SP Soc Francaise Microtechn & Chronometrie, IEEE ID FREQUENCY COMPARISONS; PRECISION AB We have conducted global positioning system (GPS) carrier-phase time-transfer experiments between the master clock (MC) at the U.S. Naval Observatory (USNO) in Washington, DC and the alternate master clock (AMC) at Schriever Air Force Base near Colorado Springs, Colorado. These clocks are also monitored on an hourly basis with two-way satellite time-transfer (TWSTT) measurements. We compared the performance of the GPS carrier-phase and TWSTT systems over a 236-d period. Because of power problems and data outages during the carrier-phase experiment, the longest continuous time span is 96 d. The data from this period show agreement with TWSTT within +/-1 ns, apart from an overall constant time offset (caused by unknown delays in the GPS hardware at both ends). For averaging times of a day, the carrier-phase and TWSTT systems have a frequency uncertainty of 2.5 and 5.5 parts in 10(15), respectively. C1 Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Larson, KM (reprint author), Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. EM Kristine.Larson@colorado.edu NR 24 TC 38 Z9 38 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 2000 VL 47 IS 2 BP 484 EP 494 DI 10.1109/58.827441 PG 11 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 294TL UT WOS:000085926400027 PM 18238571 ER PT J AU Frech, B Wells, JS Oates, CW Mitchell, J Lan, YP Kurosu, T Zink, L Hollberg, L Zibrova, T Young, BC Bergquist, JC AF Frech, B Wells, JS Oates, CW Mitchell, J Lan, YP Kurosu, T Zink, L Hollberg, L Zibrova, T Young, BC Bergquist, JC TI Sub-systems for optical frequency measurements: application to the 282-nm Hg-199(+) transition and the 657-nm Ca line SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article; Proceedings Paper CT Joint Meeting of the European-Frequency-and-Time-Forum/IEEE International Frequency Control Symposium CY APR 13-16, 1999 CL BESANCON, FRANCE SP Soc Francaise Microtechn & Chronometrie, IEEE ID COMB GENERATOR AB We are developing laser frequency measurement technologies that should allow us to construct an optical frequency synthesis system capable of measuring optical frequencies with a precision limited by the atomic frequency standards. The system will be used to interconnect and compare new advanced optical-frequency references (such as Ca, Hg+, and others) and eventually to connect these references to the Cs primary frequency standard. The approach we are taking is to subdivide optical frequency intervals into smaller and smaller pieces until we are able to use standard electronic-frequency-measurement technology to measure the smallest interval. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Opt Coating Labs Inc, Santa Rosa, CA USA. Ctr Measurement Stand, Hsinchu 30042, Taiwan. Natl Res Lab Metrol, Tsukuba, Ibaraki 305, Japan. Russian Acad Sci, PN Lebedev Phys Inst, Moscow 117924, Russia. RP Frech, B (reprint author), Schlosstr 18, D-53115 Bonn, Germany. NR 12 TC 2 Z9 2 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 2000 VL 47 IS 2 BP 513 EP 517 DI 10.1109/58.827445 PG 5 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 294TL UT WOS:000085926400031 PM 18238575 ER PT J AU Zhang, W AF Zhang, W TI Fast two-dimensional diffraction modeling for site-specific propagation prediction in urban microcellular environments SO IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY LA English DT Article DE fast two-dimensional (2-D) model; multiple diffraction; propagation; urban microcellular mobile radio ID PERSONAL COMMUNICATIONS; ATTENUATION FUNCTION; UHF PROPAGATION; UTD; EDGE AB This paper presents fast two-dimensional (2-D) diffraction modeling in the horizontal plane for site-specific propagation prediction in urban microcellular environments. The modeling makes three contributions which are: 1) the introduction and use of an extended formulation for multiple building forward diffraction; 2) a novel equivalent source simplification for parallel street multiple diffraction; and 3) the inclusion of reflections from curved surfaces of street building corners, Comparison with measurements and simulation of published results validate the 2-D modeling that significantly reduces the computation time and overcomes the limitation and difficulty of existing techniques for multiple diffraction. C1 NIST, Adv Network Technol Div, Informat Technol Lab, Wireless Commun Technol Grp, Gaithersburg, MD 20899 USA. Helsinki Univ Technol, Inst Radio Commun, Radio Lab, FIN-02015 Helsinki, Finland. RP Zhang, W (reprint author), NIST, Adv Network Technol Div, Informat Technol Lab, Wireless Commun Technol Grp, Gaithersburg, MD 20899 USA. NR 17 TC 14 Z9 14 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 0018-9545 J9 IEEE T VEH TECHNOL JI IEEE Trans. Veh. Technol. PD MAR PY 2000 VL 49 IS 2 BP 428 EP 436 DI 10.1109/25.832974 PG 9 WC Engineering, Electrical & Electronic; Telecommunications; Transportation Science & Technology SC Engineering; Telecommunications; Transportation GA 302PV UT WOS:000086375100013 ER PT J AU Kedzierski, MA AF Kedzierski, MA TI Enhancement of R123 pool boiling by the addition of hydrocarbons SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article DE heat transfer; mass transfer; pool boiling; refrigerant; mixture; R123; hydrocarbon; heat transfer coefficient ID REFRIGERANTS AB This paper presents pool boiling heat transfer data for 10 different R123/hydrocarbon mixtures. The data consisted of pool bailing performance of a GEWA-T(R) surface for pure R123 and for 10 dilute solutions of five different hydrocarbons: (1) pentane, (2) isopentane, (3) hexane, (4) cyclohexane, and (5) heptane with R123. The heat flux and the wall superheat were measured for each fluid at 277.6 K. A maximum (19 +/- 3.5)% increase over the pure R123 heat flux was achieved with the addition of 0.5% mass isopentane to R123. Other mixtures of isopentane, pentane, hexane, and cyclohexane with R123 exhibited smaller maximums than that of the R123/isopentane (99.5/0.5) mixture. Presumably, a layer enriched in hydrocarbon at the heat transfer surface caused the heat transfer enhancement. Conversely, an R123/heptane (99.5/0.5) mixture and an R123/cylcohexane (99.5/0.5) mixture exhibited only degradations with respect to the pure component performance for all test conditions. Several characteristics of the hydrocarbons were examined to determine their influence on the boiling heat transfer performance: molecular weight, molecular structure, composition, surface tension, and vapor pressure. (C) 2000 Elsevier Science Ltd and IIR. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Kedzierski, MA (reprint author), Natl Inst Stand & Technol, Bldg 226,Rm B114, Gaithersburg, MD 20899 USA. NR 22 TC 22 Z9 22 U1 1 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD MAR PY 2000 VL 23 IS 2 BP 89 EP 100 DI 10.1016/S0140-7007(99)00038-9 PG 12 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 278YV UT WOS:000085017300001 ER PT J AU Kedzierski, MA AF Kedzierski, MA TI The effect of a boiling additive on R123 condensation on a vertical integral-fin surface SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article DE heat transfer; mass transfer; condensation; refrigerant; R123; additive; heat transfer coefficient; surface; finned tube AB This payer examines the effect of the addition of 0.5% mass isopentane to R123 on the vapor-space condensation heat transfer of R123. In a previous study, the pool boiling performance of R123 was improved by adding 0.5% mass isopentane. Consequently, the impetus of the present study was a desire to quantify the consequence of the boiling additive on the condensation heat transfer performance of pure R123. In this way, the net effect of the additive on the cycle performance of pure R123 can be estimated. The data consisted of the heat flux and the wall temperature difference measurements for purr R123 and R123/isopentane (99.5/0.5) on an integral-trapezoidal-fin surface. The temperature of the saturated vapor was held constant at 313.15 K for all of the tests. On average, the R123/isopentane mixture exhibited a 4% smaller heat flux than that of pure R123. Presumably, the degradation was caused by the zeotropic behavior of the mixture, which led to a loss of available driving temperature difference for heat transfer across the liquid film. Considering that the boiling performance was enhanced on average by 10% with the addition of 0.5% mass isopentane, isopentane may still be a viable means of improving the cycle performance of R123 despite the 4% condensation heat transfer degradation. (C) 2000 Elsevier Science Ltd and IIR. All rights reserved. C1 Natl Inst Stand & Technol, Bldg Fire & Res Lab, Gaithersburg, MD 20899 USA. RP Kedzierski, MA (reprint author), Natl Inst Stand & Technol, Bldg Fire & Res Lab, Bldg 226,Rm B114, Gaithersburg, MD 20899 USA. NR 14 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD MAR PY 2000 VL 23 IS 2 BP 101 EP 111 DI 10.1016/S0140-7007(99)00039-0 PG 11 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 278YV UT WOS:000085017300002 ER PT J AU Sharpless, KE Gill, LM AF Sharpless, KE Gill, LM TI Value assignment of nutrient concentrations in five standard reference materials and six reference materials SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article ID CERTIFICATION AB A number of food-matrix reference materials (RMs) are available from the National Institute of Standards and Technology (NIST) and from Agriculture Canada through NIST. Most of these materials were originally value-assigned for their elemental composition (major, minor, and trace elements), but no additional nutritional information was provided. Two of the materials were certified for selected organic constituents. Ten of these materials (Standard Reference Material(R) [SRM] 1563 Cholesterol and Fat-Soluble Vitamins in Coconut Oil [Natural and Fortified], SRM 1566b Oyster Tissue, SRM 1570a Spinach Leaves, SRM 1974a Organics in Mussel Tissue (Mytilus edulis), RM 8415 Whole Egg Powder, RM 8418 Wheat Gluten, RM 8432 Corn Starch, RM 8433 Corn Bran, RM 8435 Whole Milk Powder, and RM 8436 Durum Wheat Flour) were recently distributed by NIST to 4 laboratories with expertise in food analysis for the measurement of proximates (solids, fat, protein, etc.), calories, and total dietary fiber, as appropriate, SRM 1846 Infant Formula was distributed as a quality control sample for the proximates and for analysis for individual fatty acids. Two of the materials (Whole Egg Powder and Whole Milk Powder) were distributed in an earlier interlaboratory comparison exercise in which they were analyzed for several vitamins. Value assignment of analyte concentrations in these 11 SRMs and RMs, based on analyses by the collaborating laboratories, is described in this paper. These materials are intended primarily for validation of analytical methods for the measurement of nutrients in foods of similar composition (based on AOAC INTERNATIONAL's fat-protein-carbohydrate triangle). They may also be used as "primary control materials" in the value assignment of in-house control materials of similar composition. The addition of proximate information for 10 existing reference materials means that RMs are now available from NIST with assigned values for proximates in 6 of the 9 sectors of the AOAC triangle, Five of these materials have values assigned for total dietary fiber-the first such information provided for materials available from NIST. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Sharpless, KE (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Stop 8392, Gaithersburg, MD 20899 USA. NR 18 TC 9 Z9 9 U1 0 U2 3 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 USA SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD MAR-APR PY 2000 VL 83 IS 2 BP 413 EP 423 PG 11 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA 299TU UT WOS:000086214600022 PM 10772181 ER PT J AU Tennyson, JM AF Tennyson, JM TI Seafoods SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article ID GENETIC IDENTIFICATION; FISH C1 Natl Seafood Inspect Lab, Pascagoula, MS 39568 USA. RP Tennyson, JM (reprint author), Natl Seafood Inspect Lab, 3209 Freder St,PO Drawer 1207, Pascagoula, MS 39568 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 USA SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD MAR-APR PY 2000 VL 83 IS 2 BP 480 EP 484 PG 5 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA 299TU UT WOS:000086214600048 ER PT J AU Carter, RG Keislar, RE AF Carter, RG Keislar, RE TI Emergency response transport forecasting using historical wind field pattern matching SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article; Proceedings Paper CT 10th Joint Conference on the Applications of Air Pollution Meteorology with the A&WMA / American-Meteorological-Society CY JAN 11-16, 1998 CL PHOENIX, ARIZONA SP Air & Waste Management Assoc, Amer Meteorol Soc ID PREDICTION; ANALOGS; MODELS; SYSTEM AB Historical pattern matching, or analog forecasting, is used to generate short-term mesoscale transport forecasts for emergency response at the Idaho National Engineering and Environmental Laboratory. A simple historical pattern-matching algorithm operating on a database from the spatially and temporally dense Eastern Idaho Mesonet is used to generate a wind held forecast, which then is input to an existing puff diffusion model. The forecasts are rated both by a tram or meteorologists and by a computer scoring method. Over 60% of tbe forecasts are rated as acceptable. The forecasts also are compared with a persistence method. using both a subjective human evaluation and root-mean-square error calculations. C1 NOAA, Air Resources Lab, Field Res Div, Idaho Falls, ID 83402 USA. RP Carter, RG (reprint author), NOAA, Air Resources Lab, Field Res Div, 1750 Foote Dr, Idaho Falls, ID 83402 USA. NR 32 TC 9 Z9 9 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAR PY 2000 VL 39 IS 3 BP 446 EP 462 DI 10.1175/1520-0450(2000)039<0446:ERTFUH>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 298QL UT WOS:000086150600014 ER PT J AU Wang, YC Benck, EC Misakian, M Edamura, M Olthoff, JK AF Wang, YC Benck, EC Misakian, M Edamura, M Olthoff, JK TI Time-resolved measurements of ion energy distributions and optical emissions in pulsed radio-frequency discharges SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID INDUCTIVELY-COUPLED PLASMA; H-MODE TRANSITION; RF REFERENCE CELL; ARGON; CHLORINE AB In pulse-modulated inductively coupled plasmas generated in CF4:Ar mixtures, a transition between a capacitive coupling mode (E mode) and an inductive coupling mode (H mode) was observed. For a pulsed plasma in a 50%CF4:50%Ar volume mixture with a peak rf power of 200 W at 13.56 MHz and a modulation frequency at 500 Hz with a duty cycle of 95%, the E --> H mode transition occurs repetitively 0.75 ms after each rf pulse is applied. This long delay in the mode transition allows us to perform not only time-resolved measurements of optical emission and electrical characteristics but also time-resolved measurements of ion energy distributions at the grounded electrode. These measurements show that a relatively short rf off period can severely perturb the equilibrium plasma state and its recovery may take much longer than the rf off period. [S0021-8979(00)02805-X]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wang, YC (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 24 TC 27 Z9 27 U1 1 U2 10 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 MAR 1 PY 2000 VL 87 IS 5 BP 2114 EP 2121 DI 10.1063/1.372148 PG 8 WC Physics, Applied SC Physics GA 287WK UT WOS:000085529500010 ER PT J AU Lu, YN Yu, QG Zamzow, JP Wang, Y Losey, GS Balazs, GH Nerurkar, VRR Yanagihara, R AF Lu, YN Yu, QG Zamzow, JP Wang, Y Losey, GS Balazs, GH Nerurkar, VRR Yanagihara, R TI Detection of green turtle herpesviral sequence in saddleback wrasse Thalassoma duperrey: A possible mode of transmission of green turtle fibropapilloma SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article ID CHELONIA-MYDAS; MARINE TURTLES AB Samples of DNA were prepared from various tissues and organs (including snout, gill, eye, brain, heart, liver, gut content, intestine, swim bladder, spleen, gallbladder, spinal cord, gonad, and muscle) of six healthy appearing reef cleaner fish. saddleback wrasses Thalassoma duperrey, captured from a cleaning station in North Kaneohe Bay, Oahu, Hawaii. The DNA samples were tested For evidence of green turtle herpesvirus infection by nested polymerase chain reaction (PCR). Green turtle herpesviral sequences were detected in snout (3/6), gill (2/6), and liver (1/6). All other tissues were negative. Except for a single nucleotide substitution (from A to G at position 48, resulting in a single amino acid change from isoleucine to methionine at position 16), the DNA sequences detected in the fish were identical to that of a newly reported green turtle herpesvirus. Although preliminary, these data represent the first evidence for an association of a herpesvirus with saddleback wrasse, suggesting that cleaner fish may serve as vectors or carriers for the transmission of the agent causing green turtle fibropapilloma. C1 Univ Hawaii, Pacific Biomed Res Ctr, Retrovirol Res Lab, Leahi Hosp, Honolulu, HI 96816 USA. Univ Hawaii Manoa, Dept Zool, Honolulu, HI 96822 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Lu, YN (reprint author), Univ Hawaii, Pacific Biomed Res Ctr, Retrovirol Res Lab, Leahi Hosp, Atherton Bldg,3675 Kilauea Ave, Honolulu, HI 96816 USA. NR 21 TC 16 Z9 16 U1 1 U2 8 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD MAR PY 2000 VL 12 IS 1 BP 58 EP 63 DI 10.1577/1548-8667(2000)012<0058:DOGTHS>2.0.CO;2 PG 6 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 300UQ UT WOS:000086271700007 ER PT J AU Doviak, RJ Bringi, V Ryzhkov, A Zahrai, A Zrnic, D AF Doviak, RJ Bringi, V Ryzhkov, A Zahrai, A Zrnic, D TI Considerations for polarimetric upgrades to operational WSR-88D radars SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID DIFFERENTIAL PROPAGATION PHASE; POLARIZATION-DIVERSITY RADARS; PRECIPITATION; RAIN; REFLECTIVITY; HAIL AB This paper reports on the steps taken by the National Severe Storms Laboratory (NSSL) to 1) develop open system hardware to facilitate upgrades to the WSR-88D (NEXRAD) radar and 2) improve identification of the type of precipitation and its quantitative measure. An engineering evaluation is made to determine if the WSR-88D antenna assembly with minimum modification could be used in a polarimetric mode. The polarimetric characteristics and radiation patterns of a research WSR-88D are briefly discussed. Considerations for the choice of polarimetric basis and design options are described. A polarimetric scheme employing simultaneous transmission of horizontally (H) and vertically (V) polarized waves is suggested for the WSR-88D, which eliminates an expensive, high-power switch. A theoretical evaluation is performed to determine the effects that feed alignment, drop canting, and backscatter depolarization have on the measurements of polarimetric parameters made with simultaneous transmission and reception of H and V signals. Experiments with the Colorado State University-Universities of Chicago and Illinois radar are performed to compare polarimetric variables obtained with alternate and simultaneous transmissions of H, V waves. Both simultaneous reception in two receivers and alternate reception in one receiver have been used. C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Doviak, RJ (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 46 TC 135 Z9 152 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAR PY 2000 VL 17 IS 3 BP 257 EP 278 DI 10.1175/1520-0426(2000)017<0257:CFPUTO>2.0.CO;2 PG 22 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 291FP UT WOS:000085723700001 ER PT J AU Sachidananda, M Zrnic, DS AF Sachidananda, M Zrnic, DS TI Clutter filtering and spectral moment estimation for Doppler weather radars using staggered pulse repetition time (PRT) SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB In this paper, a new algorithm for the estimation of spectral parameters from the signal time series, collected using the staggered pulse repetition time (PRT) transmission in a Doppler weather radar, is presented. The algorithm uses the Fourier transform and a magnitude deconvolution procedure to reconstruct the signal spectrum, and then the spectral parameters are estimated from the reconstructed spectrum. There is a significant improvement in the variance of the spectral parameter estimates compared to previously published methods of processing staggered PRT sequences. Further, a novel spectral domain clutter filtering procedure allows 1) accurate velocity estimation even if the clutter-to-signal power ratio is as high as 40 dB and 2) does nor incur the loss of velocity information in certain Doppler bands experienced by other clutter filtering techniques. With this algorithm, the staggered PRT technique becomes a practical contender for implementation on Doppler weather radars in the quest to increase the unambiguous velocity and range. C1 Indian Inst Technol, Kanpur 208016, Uttar Pradesh, India. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Zrnic, DS (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 14 TC 19 Z9 19 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAR PY 2000 VL 17 IS 3 BP 323 EP 331 DI 10.1175/1520-0426(2000)017<0323:CFASME>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 291FP UT WOS:000085723700005 ER PT J AU Weber, LA AF Weber, LA TI Vapor pressure of heptane from the triple point to the critical point SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID N-HEPTANE; TEMPERATURES; ALKANES AB me have used a metal ebulliometer to make measurements of the vapor pressures of heptane. Measurements spanned the temperature range from 335 K to 503 K, and measured pressures ranged from 30 kPa to 1597 kPa. The sample purity was determined by chromatographic analysis, and the measured pressures were adjusted for the presence of the impurities found. The adjusted results were found to be in good agreement with the best available data from the literature, and a reliable vapor pressure curve could be established for temperatures up to the critical point (540.13 K). We have also used thermodynamic calculations and published thermal data to extend the vapor pressures down to the triple point (182.603 K). We estimate that our vapor pressure curve has an uncertainty of 0.2% to 0.3% in the vicinity of the triple point, decreasing to 0.03% to 0.05% in the range 300 K to 400 K, and increasing to about 0.1% at 500 K. The calculated critical pressure was found to be (2739.7 +/- 2.5(1 sigma)) kPa. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Weber, LA (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 21 TC 20 Z9 20 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAR-APR PY 2000 VL 45 IS 2 BP 173 EP 176 DI 10.1021/je990230x PG 4 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 294GG UT WOS:000085903000008 ER PT J AU Lagalante, AF Spadi, M Bruno, TJ AF Lagalante, AF Spadi, M Bruno, TJ TI Kamlet-Taft solvatochromic parameters of eight alkanolamines SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID SOLVATION ENERGY RELATIONSHIPS; WATER PARTITION-COEFFICIENTS; PI-STAR SCALE; SOLVENT POLARITIES; OCTANOL; PREDICTION; SOLUBILITY; BASICITY; SOLUTES AB The frequency maxima of four solvatochromic probes were measured (25, 50, and 75 degrees C) in eight liquid alkanolamine solvents. Additionally, the indices of refraction of the alkanolamine solvents were measured. The frequency maxima were used to calculate solvatochromic interaction parameters. The values of the solvatochromic parameters did not vary greatly from one alkanolamine to another; however, the values of the solvatochromic parameters were high, indicating strong interaction abilities in these solvents. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div 838 01, Boulder, CO 80303 USA. RP Natl Inst Stand & Technol, Phys & Chem Properties Div 838 01, 325 Broadway, Boulder, CO 80303 USA. EM lagalant@boulder.nist.gov NR 16 TC 18 Z9 18 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAR-APR PY 2000 VL 45 IS 2 BP 382 EP 385 DI 10.1021/je990212f PG 4 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 294GG UT WOS:000085903000050 ER PT J AU Hillger, D AF Hillger, D TI Let's not forget the units! SO JOURNAL OF CHEMICAL EDUCATION LA English DT Letter C1 Colorado State Univ, NOAA, Satellite Serv, Ft Collins, CO 80523 USA. RP Hillger, D (reprint author), Colorado State Univ, NOAA, Satellite Serv, Ft Collins, CO 80523 USA. RI Hillger, Donald/F-5592-2010 OI Hillger, Donald/0000-0001-7297-2640 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 0021-9584 J9 J CHEM EDUC JI J. Chem. Educ. PD MAR PY 2000 VL 77 IS 3 BP 310 EP 310 PG 1 WC Chemistry, Multidisciplinary; Education, Scientific Disciplines SC Chemistry; Education & Educational Research GA 284NF UT WOS:000085337900011 ER PT J AU Heller, SR AF Heller, SR TI WordPerfect 9 SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 NIST, SRD, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), NIST, SRD, 100 Bur Dr, Gaithersburg, MD 20899 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 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD MAR-APR PY 2000 VL 40 IS 2 BP 513 EP 513 DI 10.1021/ci9903859 PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 298PX UT WOS:000086149300040 ER PT J AU Heller, SR AF Heller, SR TI Norton SystemWorks 2000 SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 NIST, SRD, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), NIST, SRD, Gaithersburg, MD 20899 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 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD MAR-APR PY 2000 VL 40 IS 2 BP 514 EP 514 DI 10.1021/ci9903861 PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 298PX UT WOS:000086149300041 ER PT J AU Broccoli, AJ AF Broccoli, AJ TI Tropical cooling at the last glacial maximum: An atmosphere-mixed layer ocean model simulation SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; ICE-AGE; GLOBAL CLIMATE; SPECTRAL MODEL; SENSITIVITY; PALEOCLIMATE; CO2; PALEOTEMPERATURES; RECONSTRUCTIONS; PERTURBATIONS AB The sensitivity of tropical temperature to glacial forcing is examined by using an atmosphere-mixed layer ocean (A-MLO) model to simulate the climate of the last glacial maximum (LGM) following specifications established by the Paleoclimate Modeling Intercomparison Project. Changes in continental ice, orbital parameters, atmospheric CO2, and sea level constitute a global mean radiative forcing of -4.20 W m(-2), with the vast majority of this forcing coming, in nearly equal portions, from the changes in continental ice and CO2. In response to this forcing, the global mean surface air temperature decreases by 4.0 K, with the largest cooling in the extratropical Northern Hemisphere. In the Tropics, a more modest cooling of 2.0 K (averaged from 30 degrees N to 30 degrees S) is simulated, but with considerable spatial variability resulting from the interhemispheric asymmetry in radiative forcing, contrast between oceanic and continental response, advective effects, and changes in soil moisture. Analysis of the tropical energy balance reveals that the decrease in top-of-atmosphere longwave emission associated with the tropical cooling is balanced primarily by the combination of increased reflection of shortwave radiation by clouds and increased atmospheric heat transport to the extratropics. Comparisons with a variety of paleodata indicate that the overall tropical cooling is comparable to paleoceanographic reconstructions based on alkenones and species abundances of planktonic microorganisms, but smaller than the cooling inferred from noble gases in aquifers, pollen, snow line depression, and the isotopic composition of corals. The differences in the magnitude of tropical cooling reconstructed from the different proxies preclude a definitive evaluation of the realism of the tropical sensitivity of the model. Nonetheless, the comparisons with paleodata suggest that it is unlikely that the A-MLO model exaggerates the actual climate sensitivity. The similarity between the sensitivity coefficients (i.e., the ratio of the change in global mean surface air temperature to the change in global mean radiative forcing) for the LGM simulation and a simulation of CO2 doubling suggests that similar climate feedbacks are involved in the responses to these two perturbations. More comprehensive simulation of the tropical temperature sensitivity to glacial forcing will require the use of coupled models, for which a number of technical obstacles remain. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. RP Broccoli, AJ (reprint author), Princeton Univ, NOAA, GFDL, POB 308,Forrestal Campus,US Route 1, Princeton, NJ 08542 USA. RI Broccoli, Anthony/D-9186-2014 OI Broccoli, Anthony/0000-0003-2619-1434 NR 70 TC 89 Z9 91 U1 0 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR 1 PY 2000 VL 13 IS 5 BP 951 EP 976 DI 10.1175/1520-0442(2000)013<0951:TCATLG>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 290UN UT WOS:000085696400007 ER PT J AU Ting, MF Hoerling, MP Xu, TY AF Ting, MF Hoerling, MP Xu, TY TI "Northern hemisphere teleconnection patterns during extreme phases of the zonal-mean circulation" - Reply SO JOURNAL OF CLIMATE LA English DT Article ID GCM; ATMOSPHERE; INDEX C1 Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. NOAA, NCEP, Washington, DC USA. RP Ting, MF (reprint author), Univ Illinois, Dept Atmospher Sci, 105 S Gregory Ave, Urbana, IL 61801 USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR 1 PY 2000 VL 13 IS 5 BP 1040 EP 1043 DI 10.1175/1520-0442(2000)013<1040:R>2.0.CO;2 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 290UN UT WOS:000085696400013 ER PT J AU David, L Luo, R Gilson, MK AF David, L Luo, R Gilson, MK TI Comparison of generalized born and Poisson models: Energetics and dynamics of HIV protease SO JOURNAL OF COMPUTATIONAL CHEMISTRY LA English DT Article DE generalized Born; Poisson equation; stochastic dynamics; HIV protease; implicit solvent models ID CONTINUUM SOLVATION MODEL; BOUNDARY-ELEMENT METHOD; FREE-ENERGIES; BOLTZMANN EQUATION; MOLECULAR-DYNAMICS; ALANINE DIPEPTIDE; ELECTROSTATIC FORCES; BINDING; SOLVENT; SIMULATION AB This study characterizes the accuracy of energies and forces computed with a generalized Born (GB) model and the distance-dependent dielectric (DDD) model with respect to detailed finite solutions of the Poisson equation (FDPE). Tests are done for a small molecule in solution and for HIV-1 protease with inhibitor, KNI-272. GB agrees well with FDPE for the small molecule, but less well for the protein system. The correlation between GB and FDPE energies is poorest in calculations of changes upon binding. Also, forces computed with the GB model are less accurate than energies. The DDD model is far less accurate than GB. Nanosecond stochastic dynamics simulations of HIV-1 protease with an empty active site are used to examine the consequence of the models for the conformational preferences of the active site. Interestingly, the active site flaps remain near their starting conformations in the FDPE and GB simulations but collapse into the active site in the DDD simulation. (C) 2000 John Wiley & Sons, Inc. C1 NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Gilson, MK (reprint author), NIST, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. RI Luo, Ray/I-6928-2012 OI Luo, Ray/0000-0002-6346-8271 NR 55 TC 83 Z9 83 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0192-8651 J9 J COMPUT CHEM JI J. Comput. Chem. PD MAR PY 2000 VL 21 IS 4 BP 295 EP 309 DI 10.1002/(SICI)1096-987X(200003)21:4<295::AID-JCC5>3.0.CO;2-8 PG 15 WC Chemistry, Multidisciplinary SC Chemistry GA 283UD UT WOS:000085293600005 ER PT J AU Donohue, MJ Costa, DP Goebel, ME Baker, JD AF Donohue, MJ Costa, DP Goebel, ME Baker, JD TI The ontogeny of metabolic rate and thermoregulatory capabilities of northern fur seal, Callorhinus ursinus, pups in air and water SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE metabolic rate; thermoregulation; thermal conductance; body composition; northern fur seal; Callorhinus ursinus ID HYDROGEN ISOTOPE-DILUTION; PHOCA-VITULINA-RICHARDI; ENERGY-METABOLISM; BODY SIZE; TEMPERATURE REGULATION; ARCTOCEPHALUS-GAZELLA; OXYGEN-CONSUMPTION; HARP SEAL; GROWTH; ENERGETICS AB Young pinnipeds, born on land, must eventually enter the water to feed independently. The aim of this study was to examine developmental factors that might influence this transition. The ontogeny of metabolic rate and thermoregulation in northern fur seal, Callorhinus ursinus, pups was investigated at two developmental stages in air and water using open-circuit respirometry. Mean in-air resting metabolic rate (RMR) increased significantly from 113+/-5 ml O-2 min(-1) (N=18) pre-molt to 160+/-4 ml O-2 min(-1) (N=16; means +/- S.E.M.) post-molt. In-water, whole-body metabolic rates did not differ pre- and post-molt and were 2.6 and 1.6 times in-air RMRs respectively. Mass-specific metabolic rates of pre-molt pups in water were 2.8 times in-air rates. Mean mass-specific metabolic rates of post-molt pups at 20 degrees C in water and air did not differ (16.1+/-1.7 ml O-2 min(-1) kg(-1); N=10). In-air mass-specific metabolic rates of post-molt pups were significantly lower than in-water rates at 5 degrees C (18.2+/-1.1 ml O-2 min(-1) kg(-1); N=10) and 10 degrees C (19.4+/-1.7 ml O-2 min(-1) kg(-1); N=10; means +/- S.E.M.). Northern fur seal pups have metabolic rates comparable with those of terrestrial mammalian young of similar body size. Thermal conductance was independent of air temperature, but increased with water temperature. In-water thermal conductance of pre-molt pups was approximately twice that of post-molt pups, In-water pre-molt pups matched the energy expenditure of larger post-molt pups while still failing to maintain body temperature. Pre-molt pups experience greater relative costs when entering the water regardless of temperature than do larger post-molt pups, This study demonstrates that the development of thermoregulatory capabilities plays a significant role in determining when northern fur seal pups enter the water. C1 Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. Natl Marine Fisheries Serv, Honolulu Lab, Honolulu, HI 96822 USA. RP Donohue, MJ (reprint author), Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. NR 87 TC 58 Z9 58 U1 3 U2 17 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0022-0949 J9 J EXP BIOL JI J. Exp. Biol. PD MAR PY 2000 VL 203 IS 6 BP 1003 EP 1016 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 301GT UT WOS:000086302900004 PM 10683160 ER PT J AU Buckel, JA Stoner, AW AF Buckel, JA Stoner, AW TI Functional response and switching behavior of young-of-the-year piscivorous bluefish SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE density-dependent; functional response; Morone saxatilis; Pomatomus saltatrix; seagrass; switching ID HUDSON RIVER ESTUARY; POMATOMUS-SALTATRIX; SELECTIVE PREDATION; CAPTURE SUCCESS; PREY; FISH; RECRUITMENT; POPULATION; ABUNDANCE; GROWTH AB Young-of-the-year (YOY) bluefish, Pomatomus saltatrix (L.) impose significant mortality on recently metamorphosed striped bass, Morone saxatilis (W.) in the Hudson River estuary. Field observations indicate that bluefish selectivity on striped bass increases with increasing striped bass density suggesting a density-dependent feeding response. Functional response and switching experiments were conducted to aid in determining the mechanism for this response. The type of functional response exhibited by bluefish under several prey treatments was examined. These were striped bass alone, Atlantic silversides, Menidia menidia (L.) alone, striped bass with a background density of alternative prey, and striped bass in the presence of eelgrass Zostera marina (L.). The functional response of bluefish to increasing prey density was more similar to a type I or II model than a type III model under all treatments. Switching was examined by providing bluefish both striped bass and silversides at five different ratios with and without a prey refuge, eelgrass. Bluefish did not exhibit a type III functional response or switching behavior suggesting that these mechanisms do not explain the observed density-dependent selectivity pattern in the field. Switching experiments did suggest that the presence of prey refuge can determine selectivity by YOY bluefish in the field. The abundance of submerged aquatic vegetation and other prey refuge may be important in controlling the predatory impact of bluefish on striped bass in the Hudson River. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Buckel, JA (reprint author), Univ W Florida, Dept Biol, 11000 Univ Pkwy, Pensacola, FL 32514 USA. NR 36 TC 25 Z9 26 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD MAR 1 PY 2000 VL 245 IS 1 BP 25 EP 41 DI 10.1016/S0022-0981(99)00155-0 PG 17 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 285JX UT WOS:000085386900002 ER PT J AU Grunder, H Berry, L Ellis, W Fonck, R Freidberg, J Gebbie, KB Hawryluk, RJ Montgomery, B Navratil, G Neilson, H Perkins, J Rosen, SL Schoenberg, K Weitzner, H AF Grunder, H Berry, L Ellis, W Fonck, R Freidberg, J Gebbie, KB Hawryluk, RJ Montgomery, B Navratil, G Neilson, H Perkins, J Rosen, SL Schoenberg, K Weitzner, H TI Recommendations on the nature and level of US participation in the International Thermonuclear Experimental Reactor (ITER) extension of the engineering design activities SO JOURNAL OF FUSION ENERGY LA English DT Article DE fusion energy; ITER AB The Department of Energy (DOE) Office of Energy Research chartered through the Fusion Energy Sciences Advisory Committee (FESAC) a panel to "address the topic of U.S. participation in an ITER construction phase, assuming the ITER Parties decide to proceed with construction." Given that there is expected to be a transition period of 3 to 5 years between the conclusion of the Engineering Design Activities (EDA) and the possible construction start, the DOE Office of Energy Research expanded the charge to "include the U.S. role in an interim period between the EDA and construction." This panel has heard presentations and received input from a wide cross-section of parties with an interest in the fusion program. The panel concluded it could best fulfill its responsibility under this charge by considering the fusion energy science and technology portion of the U.S. program in its entirely. Accordingly, the panel is making some recommendations for optimum use of the transition period considering the goals of the fusion program and budget pressures. C1 Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Raytheon Engineers & Constructors, New York, NY 10048 USA. Univ Wisconsin, Madison, WI 53706 USA. MIT, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Princeton Plasma Phys Lab, Princeton, NJ 08543 USA. Columbia Univ, New York, NY 10027 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Houston Lighting & Power, Wadsworth, TX 77843 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NYU, Courant Inst Math Sci, New York, NY 10012 USA. RP Grunder, H (reprint author), Thomas Jefferson Natl Accelerator Facil, Newport News, VA 23606 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0164-0313 J9 J FUSION ENERG JI J. Fusion Energy PD MAR PY 2000 VL 19 IS 1 BP 35 EP 44 DI 10.1023/A:1012277725912 PG 10 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 490XQ UT WOS:000172079300002 ER PT J AU Aarons, J Lin, B Mendillo, M Liou, K Codrescu, M AF Aarons, J Lin, B Mendillo, M Liou, K Codrescu, M TI Global Positioning System phase fluctuations and ultraviolet images from the Polar satellite SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HIGH-LATITUDES; F-REGION; IRREGULARITIES; PRECIPITATION; SCINTILLATION; MORPHOLOGY; GPS AB In a study designed to determine the temporal development of ionospheric irregularities in the auroral region in magnetic storm periods, different types of simultaneous observations were compared for the storms of January 10, April 10-11, and May 15, 1997. The data sets consisted of ultraviolet images (UVI) from the Polar satellite, phase :fluctuations and total electron content (TEC) from Global Positioning System (GPS) recordings at a large number of sites, magnetometer observations and hemispheric power precipitation. The large-scale global or macroscale picture of the magnetic storm showed the importance of universal time in the development of irregularities. The hemispheric total power picture and the global Indices such as Kp show this macroscale picture of the entire storm period. However, individual sites show differences in localized magnetic field variations and the development of irregularities; this we term the microscale. The storms of January 10 and May 15 show the importance of local magnetic time and local magnetic variations at the sites, while the storm of April 10-11 was dominated by the UT storm development. During the intense activity of the storms, total electron content shows minute-by-minute increases with the satellite moving to positions 6 km apart in the minute. The structured precipitation either directly produces irregularities or indirectly sets instability conditions for irregularity development in the auroral region. Good correlation was established for the three storms between VVI intensity and phase fluctuation development. The UVI Lyman-Birge-Hopfield-long (170 nm) emission is sensitive to 100-200 km precipitation. Phase fluctuation development undoubtedly arises from perturbations in the F region as well. Topside and bottomside soundings have shown the high occurrence of spread-F in the auroral region. The comparison of the data sets from these storms and from other studies indicates that the creation of irregularities develops from conditions existing over a large range of bottomside heights, i.e., at altitudes from 100 km to the F layer. C1 Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Aarons, J (reprint author), Boston Univ, Ctr Space Phys, 725 Commonwealth Ave, Boston, MA 02215 USA. RI Mendillo, Michael /H-4397-2014; Liou, Kan/C-2089-2016; OI Liou, Kan/0000-0001-5277-7688; Lin, Binshan/0000-0002-8481-302X NR 25 TC 34 Z9 34 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 2000 VL 105 IS A3 BP 5201 EP 5213 DI 10.1029/1999JA900409 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 288TY UT WOS:000085581600012 ER PT J AU Codrescu, MV Fuller-Rowell, TJ Foster, JC Holt, JM Cariglia, SJ AF Codrescu, MV Fuller-Rowell, TJ Foster, JC Holt, JM Cariglia, SJ TI Electric field variability associated with the Millstone Hill electric field model SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID PATTERNS AB Joule heating that is generated at high latitudes in the thermosphere because of the magnetospherically imposed electric potential is proportional to the average of the square of the electric field (E field). Most theoretical Joule heating computations use only average electric fields, resulting in heating that is proportional to the square of the average E field. The computation of the average of the square of the E field requires knowledge about the statistical characteristics of E field variability associated with the average electric field model. In this paper we present the variability associated with the Millstone Hill bin-averaged empirical E held model [Foster et al. 1986] and discuss the implications of variability as an upper atmosphere energy source. We rebinned the radar plasma drift measurements from Millstone Hill, Massachusetts, in magnetic latitude and local time as a function of auroral activity and calculated the average electric fields and the variability associated with them as reflected in the bin standard deviations. We present the E held patterns and the associated variability for both quiet and disturbed geomagnetic conditions for the four seasons. We show that for an electric field model with a Gaussian distribution of small-scale variability around the mean, the average field and the variability have equal contributions to Joule heating generation. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NOAA, Space Environm Ctr, R E SE, Boulder, CO 80303 USA. MIT, Haystack Observ, Westford, MA 01886 USA. RP Codrescu, MV (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, 325 Broadway, Boulder, CO 80303 USA. NR 15 TC 62 Z9 62 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 2000 VL 105 IS A3 BP 5265 EP 5273 DI 10.1029/1999JA900463 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 288TY UT WOS:000085581600016 ER PT J AU Clemmons, JH Pfaff, RF Lennartsson, OW Mozer, FS Singer, HJ Peterson, WK Scudder, JD Kletzing, CA Chi, PJ Wallis, DD Larson, DE AF Clemmons, JH Pfaff, RF Lennartsson, OW Mozer, FS Singer, HJ Peterson, WK Scudder, JD Kletzing, CA Chi, PJ Wallis, DD Larson, DE TI Observations of traveling Pc5 waves and their relation to the magnetic cloud event of January 1997 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID POTENTIAL MEASUREMENTS; PLASMA SHEET; INNER EDGE; SOLAR-WIND; ELECTRON; MAGNETOSPHERE; INSTRUMENT; SPACECRAFT; PROGRAM; MISSION AB Measurements of ULF waves in the Pc5 frequency range are presented and discussed. The waves were observed during the magnetic cloud event of January 1997 by instruments on the Polar satellite and ground instrumentation. These large-amplitude waves are best interpreted as traveling shear Alfven waves rather than in the usual standing-wave scenario. Characterization of the associated complex particle environment shows that the waves were largely confined to the plasma trough. Energetic protons modulated by the wave are shown to have caused modulated proton aurora. It is argued that the waves were caused by the interaction of a magnetic hole with the magnetosphere. C1 Aerospace Corp, Los Angeles, CA 90009 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52240 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Lockheed Martin Res Lab, Dept H1 11, Palo Alto, CA 94304 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Space Environm Lab R E SE, Boulder, CO 80303 USA. Magnametr, Ottawa, ON K1H 7A9, Canada. RP Clemmons, JH (reprint author), Aerospace Corp, Mail Stop M2-260,POB 92957, Los Angeles, CA 90009 USA. RI Pfaff, Robert/F-5703-2012; Scudder, Jack/D-8417-2013; Peterson, WK/A-8706-2009; OI Pfaff, Robert/0000-0002-4881-9715; Scudder, Jack/0000-0001-7975-5630; Peterson, WK/0000-0002-1513-6096; Clemmons, James/0000-0002-5298-5222; Kletzing, Craig/0000-0002-4136-3348 NR 27 TC 12 Z9 13 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 2000 VL 105 IS A3 BP 5441 EP 5452 DI 10.1029/1999JA900418 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 288TY UT WOS:000085581600031 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 2000 VL 105 IS A3 BP 5563 EP 5564 DI 10.1029/2000JA900007 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 288TY UT WOS:000085581600043 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 1 PY 2000 VL 105 IS A3 BP 5565 EP 5565 DI 10.1029/2000JA900015 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 288TY UT WOS:000085581600044 ER PT J AU Buhr, E Bergmann, D Early, EA O'Brian, TR AF Buhr, E Bergmann, D Early, EA O'Brian, TR TI Intercomparison of visual diffuse transmission density measurements SO JOURNAL OF IMAGING SCIENCE AND TECHNOLOGY LA English DT Article AB An intercomparison of visual diffuse transmission density measurements of photographic and x-ray film step tablets was completed by two national metrology institutes, the National Institute of Standards and Technology, USA, and the Physikalisch-Technische Bundesanstalt, Germany. The samples were measured by three reference densitometers according to procedures described in international documentary standards. The instruments are well characterized with estimates of their measurement uncertainties. The systematic differences between the density measurements were less than 0.010 for the photographic films and 0.015 for the x-ray films for densities as great as 3.3. C1 Phys Tech Bundesanstalt, D-3300 Braunschweig, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Buhr, E (reprint author), Phys Tech Bundesanstalt, Bundesallee 100, D-3300 Braunschweig, Germany. NR 8 TC 4 Z9 5 U1 0 U2 1 PU I S & T - SOC IMAGING SCIENCE TECHNOLOGY PI SPRINGFIELD PA 7003 KILWORTH LANE, SPRINGFIELD, VA 22151 USA SN 8750-9237 J9 J IMAGING SCI TECHN JI J. Imaging Sci. Technol. PD MAR-APR PY 2000 VL 44 IS 2 BP 156 EP 159 PG 4 WC Imaging Science & Photographic Technology SC Imaging Science & Photographic Technology GA 300CL UT WOS:000086235200008 ER PT J AU Eichenberger, AL Keller, MW Martinis, JM Zimmerman, NM AF Eichenberger, AL Keller, MW Martinis, JM Zimmerman, NM TI Frequency dependence of a cryogenic capacitor measured using single electron tunneling devices SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article; Proceedings Paper CT International Conference on Electron Transport in Mesoscopic Systems (ETSM '99) CY AUG 12-15, 1999 CL GOTHENBURG, SWEDEN AB A new type of capacitance standard based on counting electrons has been built. The operation of the standard has already given very promising results for the determination, of the value of a cryogenic vacuum-gap capacitor. The new capacitance standard operates at an effective frequency close to de, whereas capacitance metrology usually implies the use of bridges operating at a fixed frequency around 1 kHz. Therefore, the frequency dependence of the cryogenic capacitor is critical to the practical application of this standard. We present measurements of this frequency dependence using a technique that involves the same single electron tunneling devices used in the capacitance standard. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Eichenberger, AL (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Eichenberger, Ali/J-3073-2012 NR 6 TC 6 Z9 6 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD MAR PY 2000 VL 118 IS 5-6 BP 317 EP 324 DI 10.1023/A:1004681615013 PG 8 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 295ZC UT WOS:000085997700007 ER PT J AU Tulchinsky, DA Unguris, J Celotta, RJ AF Tulchinsky, DA Unguris, J Celotta, RJ TI Growth and magnetic oscillatory exchange coupling of Mn/Fe(001) and Fe/Mn/Fe(001) SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE exchange coupling; Fe whisker; thin films; SEMPA; RHEED ID SANDWICH STRUCTURES; MN LAYERS; FE(001); FE(100); FILMS; POLARIZATION; MICROSCOPY; MANGANESE AB The magnetic ordering and the interlayer exchange coupling in Mn and Fe/Mn wedge structures grown epitaxially on Fe(0 0 1) whisker substrates were investigated using scanning electron microscopy with polarization analysis (SEMPA). In bare Mn/Fe(0 0 1) samples, the magnetization of the top Mn layer is collinear with the Fe magnetization, and oscillates between ferromagnetic and antiferromagnetic alignment as the Mn thickness increases. The period of the oscillation is two layers of Mn, consistent with the growth of an antiferromagnetic Mn wedge. The bare Mn behaves very much like antiferromagnetic Cr, however the magnetic coupling in the Fe/Mn/Fe(0 0 1) sandwich structures is very different. For Mn thicknesses greater than four layers, the coupling between the top Fe layer and the Fe whisker substrate is not collinear. Between 4 to 8 layers of Mn, the direction of the top Fe in-plane magnetization lies at an angle of 60-80 degrees relative to the magnetization of the Fe substrate. Beginning at the 9th Mn layer, the direction of the coupling oscillates, with a two-layer period, between 90 degrees - phi and 90 degrees + phi, where phi is sample dependent. Values of phi between 10 and 30 degrees were observed. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Elect Phys Grp, Gaithersburg, MD 20899 USA. RP Unguris, J (reprint author), Natl Inst Stand & Technol, Elect Phys Grp, Gaithersburg, MD 20899 USA. RI Unguris, John/J-3989-2014 NR 31 TC 38 Z9 38 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD MAR PY 2000 VL 212 IS 1-2 BP 91 EP 100 DI 10.1016/S0304-8853(99)00814-8 PG 10 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 294GW UT WOS:000085904400013 ER PT J AU Zhao, H Hu, XZ Bush, MB AF Zhao, H Hu, XZ Bush, MB TI Contact damage in porcelain/Pd-alloy bilayers SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON-NITRIDE BILAYERS; CERAMIC COATINGS; MECHANICAL CHARACTERIZATION; STRENGTH DEGRADATION; HERTZIAN CONTACTS; STRESS-ANALYSIS; INDENTATION; DEFORMATION; SUBSTRATE; FRACTURE AB An analysis is made of contact damage in brittle coatings on metal substrates, using a case study of a dental porcelain coating of thickness between 0.1 and 1 mm fused onto a Pd alloy base, with spherical indenter of radii 2.38 and 3.98 mm. At large coating thicknesses (>300 mu m), the first damage takes the form of surface-initiated transverse cone cracks outside the contact. At small coating thicknesses (<300 mu m), the first damage occurs as yield in the substrate, with attendant formation of subsurface transverse median cracks in the coating. At high loads and thin coatings, both forms of transverse cracking occur, along with subsequent delamination of the ceramic/metal interface, signalling impending failure. Conditions for avoiding such transverse cracking are considered in terms of minimum coating thicknesses and maximum sustainable contact loads. General implications concerning the design of brittle coating systems for optimum damage resistance are considered, with special reference to dental crowns. C1 Univ Western Australia, Dept Mech & Mat Engn, Nedlands, WA 6907, Australia. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Zhao, H (reprint author), Univ Western Australia, Dept Mech & Mat Engn, Nedlands, WA 6907, Australia. RI Hu, Xiaozhi /H-4353-2011 NR 42 TC 31 Z9 31 U1 0 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD MAR PY 2000 VL 15 IS 3 BP 676 EP 682 DI 10.1557/JMR.2000.0100 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 290VK UT WOS:000085698400015 ER PT J AU Gonzalez, EJ White, G Wei, LH AF Gonzalez, EJ White, G Wei, LH TI Effects of microstructural evolution on the thermal conductivity of alpha-Al2O3 prepared from nano-size gamma-Al2O3 powder SO JOURNAL OF MATERIALS RESEARCH LA English DT Article AB The thermal diffusivities (D) of porous alpha-Al2O3 specimens prepared from nano-size gamma-Al2O3 powder and from conventional submicrometer-size alumina powders were measured at room temperature, and the thermal conductivity (kappa) was calculated from D. Plots of kappa versus the volume fraction of porosity (P) showed that the data from both sets of samples followed similar linear curves. Similarly, data of Vickers hardness versus P obtained from the same specimens also followed a single linear curve. The good correlation of thermal diffusivity with P suggests that grain boundaries have a lesser effect on thermal transport than porosity. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. RP Gonzalez, EJ (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 18 TC 7 Z9 7 U1 1 U2 8 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAR PY 2000 VL 15 IS 3 BP 744 EP 750 DI 10.1557/JMR.2000.0107 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 290VK UT WOS:000085698400022 ER PT J AU Gonzalez, EJ Bonevich, JE Stafford, GR White, G Josell, D AF Gonzalez, EJ Bonevich, JE Stafford, GR White, G Josell, D TI Thermal transport through thin films: Mirage technique measurements on aluminum/titanium multilayers SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID HEAT-TRANSPORT; CONDUCTIVITY; SUPERLATTICES; DIFFUSIVITY; CONDUCTANCE AB Thermal transport properties of multilayer thin films both normal and parallel to the layers were measured. Al/Ti multilayer films 3 mu m thick, with individual layers systematically varied from 2.5 to 40 nm, were studied on Si substrates. Layers of Al and Ti were nominally equal in thickness, with actual composition determined for each specimen using energy dispersive spectroscopy. The thermal diffusivity both in the plane and normal to the plane of the films (thermal conductivity divided by specific heat per volume) was found to decrease significantly with decreasing bilayer thickness. Pure Ti and Al films as well as Cu films from 0.1 to 5 mu m thick were also studied. In-plane electrical conductances of the Al/Ti multilayers were also measured. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gonzalez, EJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 32 TC 7 Z9 8 U1 0 U2 3 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD MAR PY 2000 VL 15 IS 3 BP 764 EP 771 DI 10.1557/JMR.2000.0110 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 290VK UT WOS:000085698400025 ER PT J AU Mulholland, GW Bauer, BJ AF Mulholland, George W. Bauer, Barry J. TI Nanometer calibration particles: what is available and what is needed? SO JOURNAL OF NANOPARTICLE RESEARCH LA English DT Article DE dendrimer; differential mobility analysis; calibration nanoparticles; polyamidoamine dendrimer; polystyrene spheres; small angle X-ray scattering; traceability AB Information on available polystyrene calibration spheres is presented regarding the particle diameter, uncertainty in the size, and the width of the size distribution for particles in a size range between 20 and 100 nm. The use of differential mobility analysis for measuring the single primary calibration standard in this size range, 100 nm NIST Standard Reference Material (R) 1963, is described along with the key factors in the uncertainty assessment. The issues of differences between international standards and traceability to the NIST Standard are presented. The lack of suitable polystyrene spheres in the 20-40 nm size range will be discussed in terms of measurement uncertainty and width of the size distributions. Results on characterizing a new class of 'molecular' particles known as dendrimers will be described and the possibilities of using these as size calibration standards for the size range from 3 to 15 nm will be discussed. C1 [Mulholland, George W.; Bauer, Barry J.] Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mulholland, GW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 27 TC 28 Z9 30 U1 2 U2 7 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1388-0764 J9 J NANOPART RES JI J. Nanopart. Res. PD MAR PY 2000 VL 2 IS 1 BP 5 EP 15 DI 10.1023/A:1010053806769 PG 11 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA V19IW UT WOS:000208067100003 ER PT J AU Pui, DYH Brock, JR Chen, DR Fissan, H Frisbie, CD Lyman, CE Miller, JC Mulholland, GW Pecora, R Preining, O Vo-Dinh, T AF Pui, D. Y. H. Brock, J. R. Chen, D-R. Fissan, H. Frisbie, C. D. Lyman, C. E. Miller, J. C. Mulholland, G. W. Pecora, R. Preining, O. Vo-Dinh, T. TI Instrumentation and measurement issues for nanometer particles: Workshop summary SO JOURNAL OF NANOPARTICLE RESEARCH LA English DT Article DE nanoparticles; measurements; instrumentation; standards; aerosols; colloids C1 [Pui, D. Y. H.; Chen, D-R.] Univ Minnesota, Dept Mech Engn, Particle Technol Lab, Minneapolis, MN 55455 USA. [Fissan, H.] Univ Duisburg, Dept Elect Engn, Duisburg, Germany. [Brock, J. R.] Univ Texas Austin, Dept Chem Engn, Austin, TX 78712 USA. [Frisbie, C. D.] Univ Minnesota, Dept Chem Engn, Minneapolis, MN 55455 USA. [Lyman, C. E.] Lehigh Univ, Dept Mat Sci & Engn, Bethlehem, PA 18015 USA. [Miller, J. C.] Oak Ridge Natl Lab, Biochem & Biophys Sect, Oak Ridge, TN 37831 USA. [Mulholland, G. W.] NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. [Pecora, R.] Stanford Univ, Dept Chem, Stanford, CA 94305 USA. [Preining, O.] Austrian Acad Sci, Clean Air Commiss, A-1010 Vienna, Austria. [Vo-Dinh, T.] Oak Ridge Natl Lab, Adv Monitoring Dev Grp, Oak Ridge, TN USA. RP Pui, DYH (reprint author), Univ Minnesota, Dept Mech Engn, Particle Technol Lab, 111 Church St SE, Minneapolis, MN 55455 USA. EM dyhpui@maroon.tc.umn.edu RI Frisbie, C Daniel/F-3995-2011 FU office of Basic Energy Sciences at the Department of Energy, through the Council on Energy Engineering Research (CEER) FX This work was supported by the Engineering Research Program of the office of Basic Energy Sciences at the Department of Energy, through the Council on Energy Engineering Research (CEER). The authors thank Dr. Bob Price for his active participation and encouragement. NR 9 TC 7 Z9 7 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1388-0764 J9 J NANOPART RES JI J. Nanopart. Res. PD MAR PY 2000 VL 2 IS 1 BP 103 EP 112 DI 10.1023/A:1010025905861 PG 10 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA V19IW UT WOS:000208067100012 ER PT J AU Veasey, DL Funk, DS Peters, PM Sanford, NA Obarski, GE Fontaine, N Young, M Peskin, AP Liu, WC Houde-Walter, SN Hayden, JS AF Veasey, DL Funk, DS Peters, PM Sanford, NA Obarski, GE Fontaine, N Young, M Peskin, AP Liu, WC Houde-Walter, SN Hayden, JS TI Yb/Er-codoped and Yb-doped waveguide lasers in phosphate glass SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT 15th University Conference on Glass Science CY JUN 20-23, 1999 CL UNIV MISSOURI ROLLA, ROLLA, MISSOURI SP Univ Missouri Rolla HO UNIV MISSOURI ROLLA ID PLANAR WAVE-GUIDES; MU-M; ER; SILICON; AMPLIFIER; GAIN AB We present experimental and theoretical results of our recent work on the development of waveguide lasers using rare-earth-doped phosphate glasses. An improvement has been achieved over previously reported waveguide laser results using the process of ion exchange in a commercially available Yb/Er-codoped phosphate glass composition. We have demonstrated slope efficiencies near 30% with output powers approaching 200 mW for 1540 nm Fabry-Perot waveguide lasers, These lasers are continuously tunable over approximately 70 MI. In addition, Yb-doped Fabry-Perot waveguide lasers have been fabricated and tested. These lasers operate near 1020 nm wavelength with slope efficiency of 67%. We have also realized arrays of single-frequency distributed-Bragg-reflector (DBR) waveguide lasers operating near 1.5 mu m by etching a grating in ion-exchanged waveguides. Each laser in the array operates at a different wavelength. The slope efficiencies as a function of launched pump power are 26% and the thresholds occur at approximately 50 mW of launched pump power. Temperature tuning of the wavelengths is also demonstrated. (C) 2000 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. Natl Inst Stand & Technol, High Performance Syst & Serv Div, Boulder, CO 80303 USA. Univ Rochester, Rochester Theory Ctr Opt Sci & Engn, Rochester, NY 14627 USA. Univ Rochester, Inst Opt, Rochester, NY 14627 USA. Schott Glass Technol Inc, Duryea, PA 18642 USA. RP Veasey, DL (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway,MC 815-04, Boulder, CO 80303 USA. NR 31 TC 117 Z9 121 U1 1 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD MAR PY 2000 VL 263 IS 1-4 BP 369 EP 381 DI 10.1016/S0022-3093(99)00677-8 PG 13 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 290AQ UT WOS:000085654500039 ER PT J AU Ramires, MLV de Castro, CAN Perkins, RA Nagasaka, Y Nagashima, A Assael, MJ Wakeham, WA AF Ramires, MLV de Castro, CAN Perkins, RA Nagasaka, Y Nagashima, A Assael, MJ Wakeham, WA TI Reference data for the thermal conductivity of saturated liquid toluene over a wide range of temperatures SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE high temperature; reference data; saturated liquid; thermal conductivity; toluene ID STANDARD REFERENCE DATA; PRESSURES; DIFFUSIVITY; WATER; INSTRUMENT; BENZENE; MPA AB Efficient design of industrial processes and equipment requires accurate thermal conductivity data for a variety of fluids, such as alternative refrigerants, fuels, petrochemicals, aqueous systems, molten salts, and molten metals. The accuracy of experimental thermal conductivity data is a function of the operating conditions of the instrument. Reference data are required over a wide range of conditions to verify the claimed uncertainties of absolute instruments and to calibrate relative instruments, since either type may be used to measure the thermal conductivity of fluids. Recently, accurate experimental data for the thermal conductivity of liquid toluene near the saturation line have been obtained, which allow the upper temperature limit of the previous reference-data correlation to be extended from 360 to 553 K. The thermal conductivity was measured using two transient hot-wire instruments from 300 to 550 K, the first with a bare 12.7 mu m platinum wire and the second using an anodized 25 mu m tantalum wire. Uncertainties due to the contribution of thermal radiation and the purity of the samples are discussed. The proposed value of the thermal conductivity of liquid toluene at 298.15 K and 0.1 MPa is 0.13 088 +/- 0.000 85. The quality of the data is such that new improved recommendations and recommended values can be proposed with uncertainties at 95% confidence of 1% for 189 < T < 440 K, 1.5% for 440 < T < 480 K, and 2% for 480 < T < 553 K, near the saturation line. (C) 2000 American Institute of Physics. [S0047-2689(00)00102-1]. C1 Univ Lisbon, Fac Ciencias, Dept Quim & Bioquim, CiTecMat, P-1700 Lisbon, Portugal. Univ Lisbon, Fac Ciencias, Dept Quim & Bioquim, ICAT, P-1700 Lisbon, Portugal. Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Keio Univ, Dept Mech Engn, Yokohama, Kanagawa 223, Japan. Aristotelian Univ Salonika, Fac Chem Engn, Thessaloniki 54006, Greece. Univ London Imperial Coll Sci Technol & Med, Dept Chem Engn, London SW7 2BY, England. RP Ramires, MLV (reprint author), Univ Lisbon, Fac Ciencias, Dept Quim & Bioquim, CiTecMat, Campo Grande,Ed C1,Piso 5, P-1700 Lisbon, Portugal. RI Assael, Marc/K-5545-2012; Nieto de Castro, Carlos/B-7377-2011; OI Assael, Marc/0000-0003-1221-6899; Nieto de Castro, Carlos/0000-0001-9011-5132; Perkins, Richard/0000-0002-8526-6742 NR 34 TC 63 Z9 66 U1 1 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD MAR-APR PY 2000 VL 29 IS 2 BP 133 EP 139 DI 10.1063/1.556057 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 304DF UT WOS:000086467000001 ER PT J AU Assael, MJ Bekou, E Giakoumakis, D Friend, DG Killeen, MA Millat, J Nagashima, A AF Assael, MJ Bekou, E Giakoumakis, D Friend, DG Killeen, MA Millat, J Nagashima, A TI Experimental data for the viscosity and thermal conductivity of water and steam SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE data; evaluation; liquid; steam; thermal conductivity; vapor; viscosity; water ID INTERNATIONAL TEMPERATURE SCALE; MOLECULAR-WEIGHT RELATIONSHIP; STANDARD REFERENCE DATA; BINARY-LIQUID MIXTURES; HIGH-PRESSURE; REPRESENTATIVE EQUATIONS; SUPERCOOLED WATER; SHEAR VISCOSITY; CRITICAL REGION; IONIC POLYMERS AB As part of a joint project between the International Association for the Properties of Water and Steam and the Subcommittee on Transport Properties of the International Union of Pure and Applied Chemistry Commission I.2 on Thermodynamics, all available and reliable experimental data on the viscosity and thermal conductivity of ordinary water and steam have been collected and converted to the current temperature scale (ITS-90) and a common set of units. The data are grouped according to state into four regions: the liquid phase (excluding data near 0.101 325 MPa), the steam (vapor) phase, the supercritical region (T>T-c for any pressure), and liquid water at ambient pressure (near 0.101 325 MPa) between the triple-point temperature and the normal boiling-point temperature. For each point with measured temperature and pressure (or at specified saturation conditions), a density has been computed with the current scientific standard thermodynamic formulation (IAPWS-95), and each experimental datum has been compared with the viscosity or thermal conductivity calculated from the current standard formulations for these properties. The total data collection contains 4090 points for viscosity in the range of temperatures from 238 to 1346 K with pressures to 346 MPa and 5107 points for thermal conductivity in the range of temperatures from 256 to 1191 K with pressures to 785 MPa. The current standard IAPWS formulations for the transport properties of water are based on correlations adopted in 1984 which considered experimental data available through 1980. The present study considers all data available in the earlier work, data collected in bibliographic efforts within IAPWS and documented in unpublished reports through 1988, and additional data published subsequent to the earlier reports or, in some cases, older data which were not considered in the previous compilations. Thus, this study has identified new data which were not available for the previous reviews of the transport properties of water, has identified regions in which the current standard transport property formulations can now be improved, and is intended to facilitate the development of new, more accurate, international formulations for the viscosity and thermal conductivity of water and steam. (C) 2000 American Institute of Physics. [S0047-2689(00)00202-]. C1 Aristotelian Univ Salonika, Fac Chem Engn, Thessaloniki 54006, Greece. Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Umwelt & Analyt GmbH & Co KG, NORDUM Inst, D-18196 Rostock, Germany. Keio Univ, Minato Ku, Tokyo 1088345, Japan. RP Assael, MJ (reprint author), Aristotelian Univ Salonika, Fac Chem Engn, Thessaloniki 54006, Greece. RI Assael, Marc/K-5545-2012 OI Assael, Marc/0000-0003-1221-6899 NR 354 TC 12 Z9 13 U1 2 U2 35 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD MAR-APR PY 2000 VL 29 IS 2 BP 141 EP 166 DI 10.1063/1.556056 PG 26 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 304DF UT WOS:000086467000002 ER PT J AU Atkinson, R Baulch, DL Cox, RA Hampson, RF Kerr, JA Rossi, MJ Troe, J AF Atkinson, R Baulch, DL Cox, RA Hampson, RF Kerr, JA Rossi, MJ Troe, J TI Evaluated kinetic and photochemical data for atmospheric chemistry: Supplement VIII, halogen species - IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE air pollution; atmospheric chemistry; chemical kinetics; data evaluation; gas phase; photoabsorption cross section; photochemistry; quantum yield; rate coefficient ID ABSORPTION CROSS-SECTIONS; ABSOLUTE RATE CONSTANTS; LASER FLASH-PHOTOLYSIS; MAGNETIC-RESONANCE SPECTROSCOPY; TEMPERATURE-DEPENDENT KINETICS; THERMAL UNIMOLECULAR REACTIONS; RADICAL REACTION-KINETICS; COLLISION RATE CONSTANTS; PRODUCT BRANCHING RATIO; CODATA TASK GROUP AB This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997); 28, 191 (1999)]. The present evaluation is limited to the inorganic halogen family of atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 102 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations that model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available values of enthalpies of formation of the reactant and product species. (C) 2000 American Institute of Physics. [S0047-2689(00)00302-0]. C1 Univ Calif Riverside, Air Pollut Res Ctr, Dept Environm Sci, Riverside, CA 92521 USA. Univ Calif Riverside, Air Pollut Res Ctr, Dept Chem, Riverside, CA 92521 USA. Univ Leeds, Sch Chem, Leeds LS2 9JT, W Yorkshire, England. Univ Cambridge, Dept Chem, Ctr Atmospher Sci, Cambridge CB2 1EW, England. Natl Inst Stand & Technol, Chem Kinet Data Ctr, Gaithersburg, MD 20899 USA. Univ Birmingham, Sch Chem, Birmingham B15 2TT, W Midlands, England. Ecole Polytech Fed Lausanne, LPAS, IGR, CH-1015 Lausanne, Switzerland. Univ Gottingen, Inst Chem Phys, D-37077 Gottingen, Germany. RP Atkinson, R (reprint author), Univ Calif Riverside, Air Pollut Res Ctr, Dept Environm Sci, Riverside, CA 92521 USA. RI ROSSI, Michel J./C-7878-2013 OI ROSSI, Michel J./0000-0003-3504-695X NR 355 TC 155 Z9 157 U1 5 U2 52 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD MAR-APR PY 2000 VL 29 IS 2 BP 167 EP 266 DI 10.1063/1.556058 PG 100 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 304DF UT WOS:000086467000003 ER PT J AU Park, YG Bryan, K AF Park, YG Bryan, K TI Comparison of thermally driven circulations from a depth-coordinate model and an isopycnal-layer model. Part I: Scaling-law sensitivity to vertical diffusivity SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID PARAMETER SENSITIVITY; THERMOHALINE CIRCULATION; OCEAN MODEL; TRANSPORT; BOUNDARY; DYNAMICS; FLUX; HEAT AB Two different types of numerical ocean circulation models are used in a classical idealized problem, the thermally induced circulation in an ocean basin bounded by two meridians to the east and west and by the equator and a line of constant latitude. A simple scaling theory exists for predicting poleward heat transport and the strength of meridional overturning as a function of vertical diffusivity and other external factors. However, previous studies have indicated conflicting results, and other scaling laws have been proposed. Experiments with two widely used types of numerical models, one based on depth coordinates and the other based on isopycnal layers, provide insight into the discrepancies of previous studies. In the numerical experiments vertical diffusivity is varied over a range of 200. The source of the difficulty in previous studies is in part traced to applying a fixed restoring coefficient at the upper boundary and considering the buoyancy forcing at the surface fixed irrespective of vertical diffusivity kappa. Globally or zonally averaged results show a robust agreement between the two models and support the simple scaling law in a flat-bottom basin and a bowl-shaped basin, as long as the meridional circulation is estimated along isopycnal surfaces and in situ rather than externally imposed restoring density differences are used to estimate the geostrophic-scale velocity. Over the thermocline the vertical mean of the zonally averaged zonal baroclinic pressure gradient has constant ratio to the vertical mean of the zonally averaged meridional baroclinic pressure gradient, consistent with the scaling assumptions for a diffusive thermocline. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Ctr Ocean Land Atmosphere Studies, 4041 Powder Mill Rd, Beltsville, MD 20705 USA. EM ypark@cola.iges.org RI Park, Young-Gyu /H-4585-2013 NR 23 TC 69 Z9 70 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 EI 1520-0485 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAR PY 2000 VL 30 IS 3 BP 590 EP 605 DI 10.1175/1520-0485(2000)030<0590:COTDCF>2.0.CO;2 PG 16 WC Oceanography SC Oceanography GA 292FA UT WOS:000085782400009 ER PT J AU Stephens, JC Marshall, DP AF Stephens, JC Marshall, DP TI Dynamical pathways of Antarctic Bottom Water in the Atlantic SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID WESTERN BOUNDARY CURRENT; TROPICAL NORTH-ATLANTIC; ABYSSAL CIRCULATION; DRIVEN CIRCULATION; BRAZIL BASIN; DEEP; OCEAN; TOPOGRAPHY; TRANSPORT; EQUATOR AB A reduced-gravity model is developed to represent the flow of Antarctic Bottom Water (AABW) over realistic bathymetry in an Atlantic domain. The dynamics are based on the steady, planetary-geostrophic, shallow-water equations, including a linear bottom friction and a uniform diapycnal upwelling through the top of the model layer. The model solutions are broadly consistent with observations of the distribution and transport of AABW. The flows occur predominantly along potential vorticity contours, which are in turn broadly oriented along bathymetric contours. The characteristic weak flow across potential vorticity contours of the Stommel-Arons model is present as a small addition to this stronger forced mode along potential vorticity contours. As a consequence, mass balance is maintained not by hypothesized western boundary currents as in the Stommel-Arons model, but by the interplay between topographic slope currents and interior recirculations. In particular, a transposition is found in the flow of AABW from the western side of the Brazil Basin south of the equator to the western flank of the Mid-Atlantic Ridge north of the equator. This is also consistent with an analytical result derived by extending the Parsons mechanism to an abyssal layer overlying arbitrary bathymetry. The authors suggest that the results provide a more convincing zero-order picture than the Stommel-Arons model for the circulation of AABW and perhaps for abyssal water masses in general. C1 Univ Reading, Dept Meteorol, Reading, Berks, England. RP Stephens, JC (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Post Off Box 308,Forrestal Campus, Princeton, NJ 08542 USA. RI Marshall, David/B-6767-2009 OI Marshall, David/0000-0002-5199-6579 NR 50 TC 27 Z9 29 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAR PY 2000 VL 30 IS 3 BP 622 EP 640 DI 10.1175/1520-0485(2000)030<0622:DPOABW>2.0.CO;2 PG 19 WC Oceanography SC Oceanography GA 292FA UT WOS:000085782400011 ER PT J AU Shirley, EL AF Shirley, EL TI Core and final-state excitonic effects and resonant inelastic X-ray scattering in s-p bonded solids SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT International Workshop on Inelastic X-ray Scattering CY OCT 18-21, 1998 CL LONG ISL CITY, NEW YORK SP US DOE, Div Mat Sci, Argonne Natl Lab, Blake Ind, Brookhaven Natl Lab, Brookhaven Sci Assoc, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr DE core hole ID BAND-STRUCTURE; GRAPHITE; FLUORESCENCE; ABSORPTION AB The much-discussed electron-hole attraction in resonant inelastic X-ray scattering is analyzed. Its effects on fluorescence yields and emission features are studied. While the attraction can influence both properties of fluorescence, in some cases the yield alone is affected without any change in relative strengths of spectral emission features. Model calculations of X-ray scattering are presented and compared with more realistic treatments of scattering in graphite and hBN. Both intermediate- (i.e. core-hole) and final-state (i.e. valence-hole) effects are considered. (C) 2000 Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Shirley, EL (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Bldg 221,Rm B-208, Gaithersburg, MD 20899 USA. NR 10 TC 6 Z9 6 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD MAR PY 2000 VL 61 IS 3 BP 445 EP 447 DI 10.1016/S0022-3697(99)00333-9 PG 3 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 286XL UT WOS:000085474100023 ER PT J AU Teisberg, TJ Weiher, RF AF Teisberg, TJ Weiher, RF TI Valuation of geomagnetic storm forecasts: An estimate of the net economic benefits of a satellite warning system SO JOURNAL OF POLICY ANALYSIS AND MANAGEMENT LA English DT Article C1 Teisberg Associates, Charlottesville, VA USA. NOAA, Dept Commerce, Washington, DC USA. RP Teisberg, TJ (reprint author), Teisberg Associates, Charlottesville, VA USA. NR 1 TC 3 Z9 3 U1 2 U2 4 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0276-8739 J9 J POLICY ANAL MANAG JI J. Policy Anal. Manage. PD SPR PY 2000 VL 19 IS 2 BP 329 EP 334 DI 10.1002/(SICI)1520-6688(200021)19:2<329::AID-PAM9>3.0.CO;2-P PG 6 WC Economics; Public Administration SC Business & Economics; Public Administration GA 309VH UT WOS:000086789600009 ER PT J AU Chou, KF Han, CC Lee, S AF Chou, KF Han, CC Lee, S TI Water transport in 2-hydroxyethyl methacrylate copolymer irradiated by gamma rays in air and related phenomena SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE water transport; 2-hydroxyethyl methacrylate copolymer; gamma rays ID CASE-II DIFFUSION; GLASSY POLYMERS; POLY(2-HYDROXYETHYL METHACRYLATE); MECHANICAL DEFORMATION; METHANOL TRANSPORT; HYDROGELS; GELS; VAPOR; PMMA; NMR AB The water transport in 2-hydroxyethyl methacrylate copolymer (HEMA copolymer) irradiated by gamma rays in air is investigated. The sorption data of deionized water transport in HEMA copolymer subjected to various dosages of gamma-ray irradiation are in excellent agreement with the theoretical model that accounts for case I, case II, and anomalous transport. The diffusion coefficient for case I and the velocity for case II satisfy the Arrhenius equation for all dosage levels, The transport process is exothermic and the equilibrium-swelling ratio satisfies the van't Hoff plot. The studies of the glass transition temperature of the irradiated HEMA copolymer, the pH value of deionized water after irradiation treatment, and the quantitative determination of water structures in the HEMA copolymer hydrogel are helpful in analyzing the irradiation effect on water transport in the HEMA copolymer, The effect of irradiation on the optical properties of the HEMA copolymer is also analyzed. The transmittance of a standard specimen with saturated water is lower than that before the water treatment because of the creation of holes. However, because of the formation of color centers, the color of the copolymer becomes yellow to brown and the UV cutoff wavelength of the HEMA copolymer shifts to the longer wavelength side with increasing irradiation dosage. Some of the color centers can be annihilated after water treatment. The buckled pattern on the outer surface is observed when the HEMA copolymer irradiated by a gamma ray in air is immersed in the water. This phenomenon is explained by the inhomogeneous distribution of crosslinking density. (C) 2000 John Wiley & Sons, Inc. C1 Natl Tsing Hua Univ, Dept Mat Sci, Hsinchu, Taiwan. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Lee, S (reprint author), Natl Tsing Hua Univ, Dept Mat Sci, Hsinchu, Taiwan. EM sblee@mse.nthu.edu.tw NR 54 TC 13 Z9 13 U1 1 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD MAR 1 PY 2000 VL 38 IS 5 BP 659 EP 671 DI 10.1002/(SICI)1099-0488(20000301)38:5<659::AID-POLB3>3.0.CO;2-R PG 13 WC Polymer Science SC Polymer Science GA 283RZ UT WOS:000085290700002 ER PT J AU Eppeldauer, GP AF Eppeldauer, GP TI Noise-optimized silicon radiometers SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE chopped radiation; gain; noise; photocurrent; radiometer; sensitivity; silicon photodiodes ID PHOTODIODES AB This paper describes a new, experimentally verified, noise analysis and the design considerations of the dynamic characteristics of silicon radiometers. Transimpedance gain, loop gain, and voltage gain were optimized versus frequency for photodiode current meters measuring ac and de optical radiation. Silicon radiometers with improved dynamic characteristics were built and tested. The frequency-dependent photocurrent gains were measured. The noise floor was optimized in an ac measurement mode using photodiodes of different shunt resistance and operational amplifiers with low l/f voltage and current noise. In the dark (without any signal), the noise floor of the optimized silicon radiometers was dominated by the Johnson noise of the source resistance. The Johnson noise was decreased and equalized to the amplified l/f input noise at a 9 Hz chopping frequency and 30 s integration time constant, resulting in an equivalent root-mean-square (rms) photocurrent noise of 8 x 10(-17) A. The lowest noise floor of 5 x 10(-17) A, equal to a noise equivalent power (NEP) of 1.4 x 10(-16) W at the 730 nm peak responsivity, was obtained at a 100 s integration time constant. The radiometers, optimized for ac measurements, were tested in a de measurement mode as well. Performances in ac and de measurement modes were compared. In the ac mode, a ten times shorter (40 s) overall measurement time was needed than in the de mode (400 s) to obtain the same 10(-16) A noise floor. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Eppeldauer, GP (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM george.eppeldauer@nist.gov NR 14 TC 13 Z9 13 U1 1 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 209 EP 219 DI 10.6028/jres.105.027 PG 11 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400001 PM 27551606 ER PT J AU Roder, HM Perkins, RA Laesecke, A de Castro, CAN AF Roder, HM Perkins, RA Laesecke, A de Castro, CAN TI Absolute steady-state thermal conductivity measurements by use of a transient hot-wire system SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE argon; convection; dilute gas, hot wire instrument; steady state; thermal conductivity; transient ID TRANSPORT-PROPERTIES; ROOM-TEMPERATURE; NOBLE-GASES; ARGON; COEFFICIENTS; PRESSURES; FLUIDS; APPARATUS; MPA AB A transient hot-wire apparatus was used to measure the thermal conductivity of argon with both steady-state and transient methods. The effects of wire diameter, eccentricity of the wire in the cavity, axial conduction, and natural convection were accounted for in the analysis of the steady-state measurements. Based on measurements on argon, the relative uncertainty at the 95 % level of confidence of the new steady-state measurements is 2 % at low densities. Using the same hot wires, the relative uncertainty of the transient measurements is 1 % at the 95 % level of confidence. This is the first report of thermal conductivity measurements made by two different methods in the same apparatus. The steady-state method is shown to complement normal transient measurements at low densities, particularly for fluids where the thermophysical properties at low densities are not known with high accuracy. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Lisbon, Dept Quim, P-1700 Lisbon, Portugal. Univ Lisbon, Ctr Cincias, P-1700 Lisbon, Portugal. RP Roder, HM (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM hans.roder@nist.gov; richard.perkins@nist.gov; arno.laesecke@nist.gov; carlos.castro@fc.ul.pt RI Nieto de Castro, Carlos/B-7377-2011; OI Nieto de Castro, Carlos/0000-0001-9011-5132; Perkins, Richard/0000-0002-8526-6742 NR 25 TC 39 Z9 39 U1 1 U2 9 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 221 EP 253 DI 10.6028/jres.105.028 PG 33 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400002 PM 27551607 ER PT J AU Perkins, RA Ramires, MLV de Castro, CAN AF Perkins, RA Ramires, MLV de Castro, CAN TI Thermal conductivity of saturated liquid toluene by use of anodized tantalum hot wires at high temperatures SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE anodized tantalum wire; liquid; thermal conductivity; thermal radiation; toluene; transient hot-wire AB Absolute measurements of the thermal conductivity of a distilled and dried sample of toluene near saturation are reported. The transient hot-wire technique with an anodized tantalum hot wire was used. The thermal conductivities were measured at temperatures from 300 K to 550 K at different applied power levels to assess the uncertainty with which it is possible to measure liquid thermal conductivity over wide temperature ranges with an anodized tantalum wire. The wire resistance versus temperature was monitored throughout the measurements to study the stability of the wire calibration. The relative expanded uncertainty of the resulting data at the level of 2 standard deviations (coverage factor k = 2) is 0.5 % up to 480 K and 1.5 % between 480 K and 550 K, and is limited by drift in the wire calibration at temperatures above 450 K. Significant thermal-radiation effects are observed at the highest temperatures. The radiation-corrected results agree well with data from transient hot-wire measurements with bare platinum hot wires as well as with data derived from thermal diffusivities obtained using light-scattering techniques. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Lisbon, Fac Ciencias, Dept Quim & Bioquim, P-1700 Lisbon, Portugal. Univ Lisbon, Fac Ciencias, Ctr Ciencia & Tecnol Mat, P-1700 Lisbon, Portugal. RP Perkins, RA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM richard.perkins@nist.gov; mlvr@fc.ul.pt; carlos.castro@fc.ul.pt RI Nieto de Castro, Carlos/B-7377-2011; OI Nieto de Castro, Carlos/0000-0001-9011-5132; Perkins, Richard/0000-0002-8526-6742 NR 17 TC 18 Z9 18 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 255 EP 265 DI 10.6028/jres.105.029 PG 11 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400003 PM 27551608 ER PT J AU Carey, CM Vogel, GL AF Carey, CM Vogel, GL TI Measurement of calcium activity in oral fluids by ion selective electrode: Method evaluation and simplified calculation of ion activity products SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE calcium activity; calcium ion-selective electrode; mineral saturation; plaque fluid; saliva ID PLAQUE FLUID; CARIES-FREE; INDIVIDUALS; PHOSPHATE; FLUORIDE; ENAMEL AB The activity of calcium in prague fluid is needed to calculate the saturation level of that fluid relative to the tooth mineral. One method to determine the calcium activity in very small plaque fluid samples is by micro ion-selective electrode (ISE). Two commercially available calcium ionophores, a neutral-carrier and a charged-carrier, were evaluated in micro ISEs and compared to a commercially available macro ISE using saliva as a model for plaque fluid. The neutral-carrier containing ISEs gave results consistent with those of the macro ISE. Calcium activity measurements made with micro ISEs that contained the neutral ion-carrier of whole plaque samples and plaque fluid samples obtained by centrifugation of whole plaque showed that the activities did not change due to centrifugation. Estimates of the saturation with respect to hydroxyapatite were made from these measurements. A simplified calculation method is presented to estimate the ion activity product (IAP) of the calcium-phosphate minerals. The method is based on the relative abundance of some of the possible calcium-binding species and a fixed ionic strength for plaque fluid. Calculations show that within a normal pH range for plaque fluid (5.0 to 7.5) the differences in the IAP calculations for hydroxyapatite using the simplified method are less than those estimated from propagation of uncertainty calculations. C1 Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Carey, CM (reprint author), Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. EM clifton.carey@nist.gov; gerald.vogel@nist.gov NR 26 TC 14 Z9 14 U1 0 U2 3 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 267 EP 273 DI 10.6028/jres.105.030 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400004 PM 27551609 ER PT J AU Hobbs, TG AF Hobbs, TG TI Radioactivity measurements on glazed ceramic surfaces SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE alpha; ceramics; electret ion chamber; glazes; radioactivity; scintillation counter; thorium; uranium AB A variety of commonly available household and industrial ceramic items and some specialty glass materials were assayed by alpha pulse counting and ion chamber voltage measurements for radioactivity concentrations. Identification of radionuclides in some of the items was performed by gamma spectroscopy. The samples included tableware, construction tiles and decorative tiles, figurines, and other products with a clay based composition. The concentrations of radioactivity ranged from near background to about four orders of magnitude higher. Almost every nuclide identification test demonstrated some radioactivity content from one or more of the naturally occurring radionuclide series of thorium or uranium. The glazes seemed to contribute most of the activity, although a sample of unglazed pottery greenware showed some activity. Samples of glazing paints and samples of deliberately doped glass from the World War II era were in, eluded in the test, as was a section of foam filled poster board. A glass disc with known Th-232 radioactivity concentration was cast for use as a calibration source. The results from the two assay methods are compared, and a projection of sensitivity from larger electret ion chamber devices is presented. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hobbs, TG (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM thomas.hobbs@nist.gov NR 11 TC 0 Z9 0 U1 0 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 275 EP 283 DI 10.6028/jres.105.031 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400005 PM 27551610 ER PT J AU Kim, YK Irikura, KK Ali, MA AF Kim, YK Irikura, KK Ali, MA TI Electron-impact total ionization cross sections of molecular ions SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE electron-impact ionization; molecular ion; total ionization cross sections ID DISSOCIATIVE IONIZATION; EXCITATION; N-2(+); MODEL AB The Binary-Encounter-Bethe (BEB) model for electron-impact total ionization cross sections of neutral molecules has been modified for molecular positive ions. The total ionization cross sections for H-2(+), N-2(+), CD+, and CO+ from the modified BEB formula are compared to available experimental data. The theory is in good agreement with experimental data on H-2(+), N-2(+), and CD+, but the experimental data by Belic et al. on N-2(+), and CO+ are lower than the theory. The large difference between the theory and experiment on CO+ is a strong indication of the dominance of the dissociative ionization channel, CO+-->C++O+, which was not included in the experiment. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. RP Kim, YK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM yong-ki.kim@nist.gov; karl.irikura@nist.gov; ali@atm.nist.gov RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 25 TC 35 Z9 35 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 285 EP 291 DI 10.6028/jres.105.032 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400006 PM 27551611 ER PT J AU Murthy, AV Tsai, BK Saunders, RD AF Murthy, AV Tsai, BK Saunders, RD TI Radiative calibration of heat-flux sensors at NIST: Facilities and techniques SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE heat-flux; blackbody; radiometer; sensor; calibration ID ACCURACY CRYOGENIC RADIOMETER; NATIONAL-INSTITUTE; STANDARDS AB We present an overview of the National institute of Standards and Technology high temperature blackbodies, both in operation and in development, suitable for heat-flux sensor calibration. Typical results of calibrations using the transfer technique in the 25 mm Variable-Temperature Blackbody are presented to demonstrate the long-term repeatability of the calibration technique. A comparative study of the absolute and transfer calibrations of a Garden gage in a spherical blackbody with a cooled enclosure surrounding the gage housing was conducted. Results of this study demonstrated the influence of convection associated with absolute calibration of sensors in a cooled enclosure. Plans for further development of the transfer technique to higher heat-flux levels and the associated technical issues are discussed. C1 Aero Tech Inc, Hampton, VA 23665 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Murthy, AV (reprint author), Aero Tech Inc, Hampton, VA 23665 USA. EM murthy.annageri@nist.gov; benjamin.tsai@nist.gov; robert.saunders@nist.gov NR 12 TC 23 Z9 24 U1 1 U2 5 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD MAR-APR PY 2000 VL 105 IS 2 BP 293 EP 305 DI 10.6028/jres.105.033 PG 13 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 330WP UT WOS:000087984400007 PM 27551612 ER PT J AU Migler, KB AF Migler, KB TI Droplet vorticity alignment in model polymer blends SO JOURNAL OF RHEOLOGY LA English DT Article ID OLDROYD-B FLUID; SHEAR-FLOW; MORPHOLOGY DEVELOPMENT; VISCOELASTIC FLUIDS; ELASTIC PROPERTIES; DEFORMATION; BREAKUP; MICRORHEOLOGY; DISPERSION; DYNAMICS AB We utilize stroboscopic optical microscopy to monitor the shear induced deformation of polymeric droplets in an immiscible polymeric matrix and find that under conditions of high droplet elasticity, the droplets can align in the vorticity direction. We consider the case where the viscosity ratio of the two phases is near unity but the elasticity ratio of the droplet to the matrix is greater than 100. This is achieved by using a matrix phase of polydimethylsiloxane and a droplet phase of a polyisobutylene based "Boger" fluid. In the limit of weak shear and small droplets, the droplet alignment is along the shear direction, whereas for strong shear and large droplets, the alignment is along the vorticity direction. There is a range of conditions for which alignment can be along either axis. For droplets aligned along the vorticity axis, the distribution of aspect ratios is broad. The kinetic transformation from droplet flow alignment to vorticity alignment upon increase of shear flow has been observed, as well as the relaxation back to a spherical shape upon cessation of shear. We deduce from the kinetic experiments that the thickness in the gradient direction is less than that in the flow and vorticity directions. (C) 2000 The Society of Rheology. [S0148-6055(00)00202-9]. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Migler, KB (reprint author), NIST, Div Polymers, 100 Bur Dr, Gaithersburg, MD 20899 USA. NR 43 TC 36 Z9 36 U1 2 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0148-6055 J9 J RHEOL JI J. Rheol. PD MAR-APR PY 2000 VL 44 IS 2 BP 277 EP 290 DI 10.1122/1.551086 PG 14 WC Mechanics SC Mechanics GA 290AY UT WOS:000085655200006 ER PT J AU Drohat, AC Stivers, JT AF Drohat, AC Stivers, JT TI NMR evidence for an unusually low N1 pK(a) for uracil bound to uracil DNA glycosylase: Implications for catalysis SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID BASE-EXCISION-REPAIR; NUCLEOSIDES; KINETICS; ACIDS; SHIFT C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. RP Stivers, JT (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. NR 24 TC 71 Z9 72 U1 0 U2 3 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 MAR 1 PY 2000 VL 122 IS 8 BP 1840 EP 1841 DI 10.1021/ja993254x PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 289NV UT WOS:000085629600048 ER PT J AU Wheeler, M Kiladis, GN Webster, PJ AF Wheeler, M Kiladis, GN Webster, PJ TI Large-scale dynamical fields associated with convectively coupled equatorial waves SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MADDEN-JULIAN OSCILLATION; MERIDIONAL WIND OSCILLATIONS; WAVENUMBER-FREQUENCY DOMAIN; UPPER TROPOSPHERIC WAVES; 40-50 DAY OSCILLATION; ROSSBY-GRAVITY-WAVES; TOGA COARE IOP; TROPICAL PACIFIC; WESTERN PACIFIC; VERTICAL STRUCTURE AB Convectively coupled equatorial waves, as previously detected in studies of wavenumber-frequency spectra of tropical clouds, are studied in more detail. Composite dynamical structures of the waves are obtained using linear regression between selectively filtered satellite-observed outgoing longwave radiation (OLR) data, and various fields from a global reanalysis dataset. The selective filtering of the OLR was designed to isolate the convective variations contributing to spectral peaks that lie along the equatorial wave dispersion curves for equivalent depths in the range of 12-50 m. The waves studied are the Kelvin, n = 1 equatorial Rossby (ER), mixed Rossby-gravity, n = 0 eastward inertio-gravity, n = 1 westward inertio-gravity (WIG), and n = 2 WIG waves. The horizontal structures of the dynamical fields associated with the waves are all generally consistent with those calculated from inviscid equatorial beta-plane shallow water theory. In the vertical, there are statistically significant structures spanning the depth of the troposphere, and for all but the ER wave there are associated vertically propagating signals extending into the equatorial stratosphere as well. In zonal cross sections, the vertical structure of the temperature anomaly field appears, for all but the ER wave, as a "boomerang"-like shape, with the "elbow" of the boomerang occurring consistently at the 250-hPa level. The tilts of the boomerang imply upward phase propagation throughout most of the troposphere, and downward phase propagation above. The deep convection of the waves occurs in regions of anomalously cold temperatures in the lower troposphere, warm temperatures in the upper troposphere, and cold temperatures at the level of the tropopause. Such a vertical structure appears to indicate that waves of relatively short vertical wavelengths (L-z similar to 10 km) are indeed important for the coupling of large-scale dynamics and convection. The deeper structure of the convectively coupled ER wave, on the other hand, is thought to be an indication of the effects of basic-state vertical shear. Finally, the scales of the waves in the equatorial lower stratosphere that are forced by the convectively coupled equatorial waves are quite consistent with those found in many previous studies. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO USA. RP Natl Ctr Atmospher Res, Adv Study Program, POB 3000, Boulder, CO 80307 USA. EM mwheeler@ucar.edu RI Wheeler, Matthew/C-9038-2011 OI Wheeler, Matthew/0000-0002-9769-1973 NR 99 TC 304 Z9 306 U1 2 U2 19 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 1 PY 2000 VL 57 IS 5 BP 613 EP 640 DI 10.1175/1520-0469(2000)057<0613:LSDFAW>2.0.CO;2 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 301MT UT WOS:000086314500001 ER PT J AU Davies-Jones, R AF Davies-Jones, R TI A Lagrangian model for baroclinic genesis of mesoscale vortices. Part I: Theory SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID FROUDE-NUMBER FLOW; POTENTIAL VORTICITY; ISOLATED MOUNTAIN; LINEAR-THEORY; LEE VORTICES; ATMOSPHERE; GENERATION; EVOLUTION; ROTATION; VORTEX AB The problem of weakly stratified, weakly sheared flow over (or under) obstacles is solved approximately by using a Lagrangian approach that obtains solutions on isentropic or Bernoulli surfaces and hence reveals the vortex lines immediately. The new method is based on a decomposition of the vorticity in dry, inviscid, isentropic flow into baroclinic and barotropic components. The formulas for both baroclinic and barotropic vorticity are exact formal solutions of the vorticity equation. A nonhydrostatic Lagrangian model approximates these solutions based on a primary-flow-secondary-flow approach. The assumed primary flow is a three-dimensional steady potential flow so that it is a solution of the governing inviscid equations only in the absence of stratification and preexisting vorticity. It is chosen to be irrotational in order to eliminate the primary Row as the origin of rotation. Three particular potential Rows are chosen for their simplicity and because pieces of them approximate mesoscale atmospheric flows. The secondary Row is the correction needed to give an improved approximation to the actual Row. The Lagrangian model computes the secondary vorticity that develops owing to the introduction of stratification and vorticity in the upstream horizontally homogeneous environment as secondary effects without modification of the primary Row. Potential vorticity is conserved and is zero because both the barotropic and the baroclinic vortex lines lie in the isentropic Surfaces. The baroclinic component of vorticity, zero initially, depends on the gradient of cumulative temperature (the Lagrangian integral of temperature following an air parcel) and on the local entropy gradient. In a particular isentropic surface, it is determined by the local static stability and by horizontal gradients of the height and the cumulative height perturbations of parcels in the surface. For weak stable stratification, it is proven that the vertical baroclinic vorticity is cyclonic (anticyclonic) on the entire right (left) side of the Row, upstream as well as downstream of the height extremum. A time-dependent linearized version of the model is used to show how the baroclinic vortex lines evolve initially. Barotropic vorticity is determined by the property that barotropic vortex lines, which are straight and horizontal in the upstream environment, are frozen into the fluid and move with it. The component normal to the surfaces of the secondary velocity induced by the baroclinic and barotropic vorticity is deduced qualitatively. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Davies-Jones, R (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 42 TC 19 Z9 19 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 1 PY 2000 VL 57 IS 5 BP 715 EP 736 DI 10.1175/1520-0469(2000)057<0715:ALMFBG>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 301MT UT WOS:000086314500006 ER PT J AU Harrington, JY Feingold, G Cotton, WR AF Harrington, JY Feingold, G Cotton, WR TI Radiative impacts on the growth of a population of drops within simulated summertime Arctic stratus SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID STRATOCUMULUS CLOUDS; HEAT BUDGETS; MICROPHYSICS; MODEL; CONDENSATION; COLLECTION; MASS AB The impact of solar heating and infrared cooling on the growth of a population of drops is studied with two numerical modeling frameworks. An eddy-resolving model (ERM) simulation of Arctic stratus clouds is used to generate a dataset of 500 parcel trajectories that follow the mean dynamic motions of the simulated cloud. The 500-parcel dataset is used to drive a trajectory ensemble model (TEM) coupled to an explicit microphysical model that includes the radiative term in the vapor growth equation. The second framework is that of the ERM itself. Results from the TEM show that the production of drizzle-sized drops is strongly dependent upon parcel cloud-top residence time for both radiative- and nonradiative influenced growth. Drizzle-sized drops can be produced between 20 and 50 min earlier through the inclusion of the radiative term. which corroborates, earlier results. The radiative effect may also cause drops with r < 10 mu m to evaporate, producing a bimodal size spectrum. Parcel cloud-top residence times as short as 12 min can initiate this bimodal spectrum. TEM results show that the radiative effect increases drizzle drop mass predominately in parcels that Ir tendl to contribute to drizzle even in the absence of the radiative term. Activation of large cloud condensation nuclei appears to have a larger effect un drizzle production than does the radiative term, ERM simulations show a weak overall influence of the radiative term. Drizzle onset occurs earlier when the radiative term is included (about 20 min), but there is no strong change in the overall structure or evolution of the cloud. C1 Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. NOAA, Environm Technol Lab, Boulder, CO USA. RP Harrington, JY (reprint author), Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. EM jerry.harrington@gi.alaska.edu RI Feingold, Graham/B-6152-2009 NR 32 TC 48 Z9 49 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR 1 PY 2000 VL 57 IS 5 BP 766 EP 785 DI 10.1175/1520-0469(2000)057<0766:RIOTGO>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 301MT UT WOS:000086314500009 ER PT J AU Collings, BC Cundiff, ST Akhmediev, NN Soto-Crespo, JM Bergman, K Knox, WH AF Collings, BC Cundiff, ST Akhmediev, NN Soto-Crespo, JM Bergman, K Knox, WH TI Polarization-locked temporal vector solitons in a fiber laser: experiment SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID BIREFRINGENT OPTICAL FIBERS; SATURABLE BRAGG REFLECTOR; PULSE-PROPAGATION; DISPERSION; LOCKING; INSTABILITIES; EVOLUTION; DYNAMICS; DEVICES; STATES AB We experimentally observe polarization-locked vector solitons in a passively mode-locked fiber laser. The vector soliton pulse is composed of components along both principal polarization axes of the linearly birefringent laser cavity. For certain values of birefringence and pulse energy these components propagate with a constant relative optical phase of +/- pi/2, and hence the pulse has a fixed elliptical polarization state. The linear birefringence of the cavity is canceled by the nonlinear birefringence created by the unequal amplitudes of the two polarization components. This dynamic equalization of the phase velocities of the components results in the stable propagation of an elliptically polarized vector soliton pulse. Under different conditions we also observe the nonlinear instability of the fast principal axis as an intracavity pulse linearly polarized along the slow axis of the cavity. We present the experimental characterization of both the polarization-locked vector soliton and the fast axis instability and discuss the nonlinear mechanism creating both phenomena. (C) 2000 Optical Society of America [S0740-3224(00)01003-1] OCIS codes: 060.5530, 190.4370, 140.4050, 320.7090, 140.3500. C1 Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. Bell Labs, Lucent Technol, Holmdel, NJ 07733 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Australian Natl Univ, Ctr Opt Sci, Australian Photon Cooperat Res Ctr, Canberra, ACT 0200, Australia. CSIC, Inst Opt, E-28006 Madrid, Spain. RP Collings, BC (reprint author), Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. RI Cundiff, Steven/B-4974-2009 OI Cundiff, Steven/0000-0002-7119-5197 NR 34 TC 58 Z9 58 U1 1 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 2000 VL 17 IS 3 BP 354 EP 365 DI 10.1364/JOSAB.17.000354 PG 12 WC Optics SC Optics GA 294MY UT WOS:000085916100002 ER PT J AU Soto-Crespo, JM Akhmediev, NN Collings, BC Cundiff, ST Bergman, K Knox, WH AF Soto-Crespo, JM Akhmediev, NN Collings, BC Cundiff, ST Bergman, K Knox, WH TI Polarization-locked temporal vector solitons in a fiber laser: theory SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID BIREFRINGENT OPTICAL FIBERS; SATURABLE BRAGG REFLECTOR; MODE-LOCKING; PULSE-PROPAGATION; SOLITARY WAVES; STABILITY; EVOLUTION; ABSORBER; PHASE; AMPLITUDES AB Stable polarization-locked temporal vector solitons are found in a saturable absorber mode-locked fiber laser with weak cavity birefringence. The system is theoretically modeled with two coupled complex Ginzburg-Landau equations that include fiber birefringence, spectral filtering, saturable gain, and slow saturable absorption. The solutions to this system are similar to those for elliptically polarized vector solitons in a lossless birefringent fiber. Numerical simulations show qualitative agreement with experimental results. (C) 2000 Optical Society of America [S0740-3224(00)00603-2] OCIS codes: 190.5530, 260.1440, 260.5210, 140.3510, 140.4050. C1 CSIC, Inst Opt, E-28006 Madrid, Spain. Australian Natl Univ, Ctr Opt Sci, Australian Photon Cooperat Res Ctr, Canberra, ACT 0200, Australia. Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Bell Labs, Lucent Technol, Holmdel, NJ 07733 USA. RP CSIC, Inst Opt, Serrano 121, E-28006 Madrid, Spain. RI Cundiff, Steven/B-4974-2009 OI Cundiff, Steven/0000-0002-7119-5197 NR 39 TC 31 Z9 31 U1 1 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 EI 1520-8540 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 2000 VL 17 IS 3 BP 366 EP 372 DI 10.1364/JOSAB.17.000366 PG 7 WC Optics SC Optics GA 294MY UT WOS:000085916100003 ER PT J AU Buckley, LJ Bradley, TM Allen-Guilmette, J AF Buckley, LJ Bradley, TM Allen-Guilmette, J TI Production, quality, and low temperature incubation of eggs of Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus in captivity SO JOURNAL OF THE WORLD AQUACULTURE SOCIETY LA English DT Article ID OVULATION; FISH AB Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus broodstock maintained under altered regimens of temperature and photoperiod spawned up to 8 mo per year. The cod broodstock produced viable embryos from October through June. The haddock broodstock produced viable embryos from December through May. Egg diameters were Largest during the middle of the spawning season when water temperature was at a minimum, resulting in an inverse relationship between egg diameter and water temperature in both species. Egg quality was high, as evaluated by buoyancy, fertilization rate, regularity of early cleavage, end percent viable hatch. Low temperature incubation of cod and haddock eggs extended the embryonic period. Cod embryos tolerated a wider range of temperatures than haddock. High mortality (> 90%) was observed before hatching in haddock embryos incubated at 1 C. Atlantic cod embryos hatched at temperatures as low as -1 C, extending the embryonic period to 59 d. At 8 C Atlantic cod and haddock embryos hatched in 11-12 d. To determine if extending the embryo incubation time hy using low temperatures had a detrimental effect, embryos were incubated through hatch at either 1 C or 0 C, and the larvae from both groups reared at 6 C. Growth and early survival of larvae were comparable in both treatments. C1 Univ Rhode Isl, Grad Sch Oceanog, NOAA, CMER Program, Narragansett, RI 02882 USA. NOAA, NMFS, Narragansett Lab, Narragansett, RI 02882 USA. Univ Rhode Isl, Dept Fisheries Anim & Vet Sci, Kingston, RI 02881 USA. RP Buckley, LJ (reprint author), Univ Rhode Isl, Grad Sch Oceanog, NOAA, CMER Program, Narragansett, RI 02882 USA. NR 16 TC 22 Z9 23 U1 2 U2 3 PU WORLD AQUACULTURE SOCIETY PI BATON ROUGE PA LOUISIANA STATE UNIV, 143 J M PARKER COLISEUM, BATON ROUGE, LA 70803 USA SN 0893-8849 J9 J WORLD AQUACULT SOC JI J. World Aquacult. Soc. PD MAR PY 2000 VL 31 IS 1 BP 22 EP 29 DI 10.1111/j.1749-7345.2000.tb00694.x PG 8 WC Fisheries SC Fisheries GA 309HA UT WOS:000086761400003 ER PT J AU Hart, DR Stone, L Berman, T AF Hart, DR Stone, L Berman, T TI Seasonal dynamics of the Lake Kinneret food web: The importance of the microbial loop SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID MESOCYCLOPS-LEUCKARTI CLAUS; FRESH-WATER ZOOPLANKTON; OLIGOTROPHIC LAKE; ISRAEL; CARBON; ECOSYSTEM; BACTERIA; BACTERIOPLANKTON; PHYTOPLANKTON; PICOPLANKTON AB The role of bacteria and protozoa in the food web of Lake Kinneret was examined for 14 seasons over a 4-yr period (1989-1992) using a mass-balanced carbon Bur model and network analysis. These microorganisms supplied nearly half of the carbon requirements of metazoan zooplankton grazers during the late winter-spring Peridinium bloom, when the lake was in its most eutrophic phase. The level of primary productivity was not seen to have a significant effect on the relative amounts of carbon passing from bacteria and protozoa to higher trophic levels, Rather, this depended on the proportion of photosynthetically fixed carbon that originated from "inedible" net-phytoplankton and the efficiency with which bacterial carbon was transferred to metazoans. The importance of the microbial loop as a carbon source to higher trophic levels in Lake Kinneret was a result of the often high levels of inedible net-phytoplankton (mostly Peridinium gatunense). The higher levels also occurred because bacterial production was transferred to metazoans in a relatively efficient one- or two-step process. These results indicate that even in eutrophic environments, bacteria and protozoa can supply significant amounts of carbon to metazoans. C1 Tel Aviv Univ, Dept Zool, IL-69978 Tel Aviv, Israel. Kinneret Limnol Lab, Tiberias, Israel. RP Hart, DR (reprint author), NE Fisheries Sci Ctr, 166 Water St, Woods Hole, MA 02543 USA. NR 67 TC 38 Z9 42 U1 0 U2 10 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0024-3590 EI 1939-5590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAR PY 2000 VL 45 IS 2 BP 350 EP 361 PG 12 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 292YB UT WOS:000085822300010 ER PT J AU Slotwinski, JA Sydnor, CR Lopez-Sanchez, AL AF Slotwinski, JA Sydnor, CR Lopez-Sanchez, AL TI Variable waveform excitation of ceramic element transducers for ASTM E127 type reference block calibrations SO MATERIALS EVALUATION LA English DT Article DE ASTM 227; ceramic transducers; FBH; membrane hydrophone; PVDF; reference blocks; ultrasound AB Nominally identical ceramic element ultrasonic transducers have been used successfully to calibrate ASTM E127 type flat bottom hole (FBH) aluminum reference blocks. The transducers all had nominal center frequencies of 5 MHz, and nominal element diameters of 9.5 mm (0.38 in.) or 10.7 mm (0.42 in.). The inherent performance variability among these transducers runs eliminated by monitoring and matching the frequency content of the generated ultrasonic pressure pulses. The pulses were monitored with a polymer polyvinylidene (PVDF) membrane hydrophone and the frequency content was matched by adjusting the shape oft he excitation waveform. Several different common excitation shapes were examined in detail. Results indicate that this type of tuning procedure will result in similar performance among nominally identical ceramic element transducers. This may ultimately allow for the routine reliable calibration of long metal path blocks that cannot be calibrated using quartz element ultrasonic transducers as currently stipulated in E127. C1 NIST, Mfg Engn Lab, Gaithersburg, MD 20899 USA. Acoust Vibrat Grp, Queretaro, Mexico. RP Slotwinski, JA (reprint author), NIST, Mfg Engn Lab, Gaithersburg, MD 20899 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD MAR PY 2000 VL 58 IS 3 BP 455 EP 461 PG 7 WC Materials Science, Characterization & Testing SC Materials Science GA 291DN UT WOS:000085719000013 ER PT J AU Coakley, KJ Clark, AV Hehman, CS AF Coakley, KJ Clark, AV Hehman, CS TI Empirical modelling of electromagnetic acoustic transducer data SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE acoustic birefringence; material inhomogeneity; nonlinear regression; signal alignment; spatial variability; statistical modelling; stress determination; ultrasonics AB We characterize the observed phase and amplitude of acoustic birefringence data collected with an electromagnetic acoustic transducer. Our characterization models are extended versions of an idealized model for acoustic birefringence. In the extended models, angle-dependent terms account for observed variability in phase and amplitude which is not predicted by the idealized theory. Possible sources of this extra variability include material inhomogeneity and angle-dependent sensor gain. The adjustable parameters in the model are determined by minimizing the sum of the squared phase residuals plus the sum of the squared amplitude residuals. To facilitate convergence, we determine the model parameters by fitting the extended models sequentially according to model complexity. Ten experimental data sets were collected from the same sample. We estimate the mean value of each model parameter and its associated standard error. For each extended model, we estimate the mean phase delay between the fast and slow modes. We also estimate the mean rotation angle of the pure-mode polarization directions (relative to a reference coordinate system in the specimen). From run to run, we observed phase data drift. However, the difference between the phases of the slow and fast modes did not follow this drift. C1 Univ Colorado, NIST, Stat Engn Div, Boulder, CO 80309 USA. Univ Colorado, NIST, Div Mat Reliabil, Boulder, CO 80309 USA. RP Univ Colorado, NIST, Stat Engn Div, Boulder, CO 80309 USA. NR 9 TC 0 Z9 0 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD MAR PY 2000 VL 11 IS 3 BP 193 EP 200 DI 10.1088/0957-0233/11/3/304 PG 8 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 300EB UT WOS:000086238900004 ER EF