FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Wong-Ng, W Cook, LP Kearsley, A Greenwood, W AF Wong-Ng, W Cook, LP Kearsley, A Greenwood, W TI Primary phase field of the Pb-doped 2223 High-T-c superconductor in the (Bi, Pb)-Sr-Ca-Cu-O system SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Review DE high-T-c superconductor; Pb-doped 2223; BSCCO; phase equilibria; primary phase field ID OXYGEN PARTIAL-PRESSURE; AG-SHEATHED TAPES; COMPOSITE CONDUCTORS; O SYSTEM; FORMATION MECHANISM; (BI,PB)-SR-CA-CU-O SYSTEM; BI2SR2CA2CU3O10 PHASE; BI(PB)-2223 PHASE; CRYSTAL-CHEMISTRY; TEXTURE FORMATION AB Both liquidus and subsolidus phase equilibrium data are of central importance for applications of high temperature superconductors in the (Bi, Pb)-Sr-Ca-Cu-O system, including material synthesis, melt processing and single crystal growth. The subsolidus equilibria of the 110 K high-T-c Pb-doped 2223 ([Bi, Pb], Sr, Ca, Cu) phase and the location of the primary phase field (crystallization field) have been determined in this study. For the quantitative determination of liquidus data, a wicking technique was developed to capture the melt for quantitative microchemical analysis. A total of 29 five-phase volumes that include the 2223 phase as a component was obtained. The initial melt compositions of these volumes range from a mole fraction of 7.3 % to 28.0 % for Bi, 11.3 % to 27.8 % for Sr, 1.2 % to 19.4 % for Pb, 9.8 % to 30.8 % for Ca, and 17.1 % to 47.0 % for Cu. Based on these data, the crystallization field for the 2223 phase was constructed using the convex hull technique. A section of this "volume" was obtained by holding two components of the composition at the median value, allowing projection on the other three axes to show the extent of the field. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Wong-Ng, W (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 98 TC 21 Z9 21 U1 6 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 MAY-JUN PY 1999 VL 104 IS 3 BP 277 EP 289 DI 10.6028/jres.104.020 PG 13 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 223VZ UT WOS:000081863400004 ER PT J AU Cross, JO Elam, WT Woicik, JC Sorensen, LB AF Cross, JO Elam, WT Woicik, JC Sorensen, LB TI Reliability of structural parameters determined from DAFS data using the iterative dispersion integral algorithm SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 10th International Conference on XAFS (XAFS X) CY AUG 10-14, 1998 CL ILLINOIS INST TECHNOL, CHICAGO, ILLINOIS HO ILLINOIS INST TECHNOL DE DAFS; Kramers-Kronig; analysis ID ANOMALOUS FINE-STRUCTURE; DIFFRACTION AB The iterative Kramers-Kronig (IKK) dispersion integral algorithm is commonly used to isolate the complex resonant scattering amplitude Delta f = f' + if " from measured diffraction anomalous fine structure (DAFS) intensity data, where the imaginary part f " is then analyzed in the same manner as the absorption coefficient mu. We have performed studies using simulated and experimental DAFS data to evaluate the reliability of structural parameters determined from f " resolved by the IKK algorithm. The results of a few of these experiments are presented here. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Washington, Seattle, WA 98195 USA. RP Cross, JO (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 7 TC 5 Z9 5 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD MAY 1 PY 1999 VL 6 BP 335 EP 337 DI 10.1107/S0909049598018226 PN 3 PG 3 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 212NA UT WOS:000081221700077 PM 15263299 ER PT J AU Ravel, B Bouldin, CE Renevler, H Hodeau, JL Berar, JF AF Ravel, B Bouldin, CE Renevler, H Hodeau, JL Berar, JF TI Edge separation using diffraction anomalous fine structure SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 10th International Conference on XAFS (XAFS X) CY AUG 10-14, 1998 CL ILLINOIS INST TECHNOL, CHICAGO, ILLINOIS HO ILLINOIS INST TECHNOL DE DAFS; BaTiO3; site separation ID X-RAY-ABSORPTION AB We exploit the crystallographic sensitivity of the Diffraction Anomalous Fine-Structure (DAFS) measurement to separate the fine structure contributions of different atomic species with closely spaced resonant energies. In BaTiO3 the Ti K edge and Ba Lm edges are separated by 281 eV, or about 8.2 Angstrom(-1), thus severely limiting the information content of the Ti K edge signal. Using the site selectivity of DAFS we can separate the two fine structure spectra using an iterative Kramers-Kronig method, thus extending the range of the Ti K edge spectrum. This technique has application to many rare earth/transition metal compounds, including many magnetic materials of technological significance for which K and L edges overlap in energy. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. CNRS, Cristallog Lab, F-38042 Grenoble 09, France. RP Ravel, B (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 11 TC 2 Z9 2 U1 1 U2 1 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD MAY 1 PY 1999 VL 6 BP 338 EP 340 DI 10.1107/S0909049598013648 PN 3 PG 3 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 212NA UT WOS:000081221700078 PM 15263300 ER PT J AU Nelson, E Woicik, J Pianetta, P AF Nelson, E Woicik, J Pianetta, P TI Direct measurement of valence charge asymmetry in GaAs using X-ray standing waves SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 10th International Conference on XAFS (XAFS X) CY AUG 10-14, 1998 CL ILLINOIS INST TECHNOL, CHICAGO, ILLINOIS HO ILLINOIS INST TECHNOL DE X-ray standing waves; valence band photoemission spectroscopy; bond polarity ID SURFACE AB Through detection of valence photoelectrons, the technique of xray standing waves directly measured the charge asymmetry of the GaAs valence band. Using the back-reflection geometry for the (111) and (TTT) diffraction planes, we determine from the coherent distances of the standing waves, that a majority of the valence electrons reside on the As atoms of this heteropolar crystal. These measurements agree well with the GaAs bond polarity calculated from the values of the Hartree-Fock terms. In contrast, the valence standing waves for germanium determine the valence charge to be symmetric. The coherent fractions of the standing waves of Ge and GaAs are reduced compared to those of core-level standing waves, indicating the delocalization of valence charge. This technique using low energy x-rays together with valence photoelectron detection can be more generally applied to the study of chemical bonding. C1 Stanford Synchrotron Radiat Lab, Stanford, CA 94309 USA. NIST, Gaithersburg, MD 20899 USA. RP Nelson, E (reprint author), Stanford Synchrotron Radiat Lab, POB 4349,Mail Stop 99, Stanford, CA 94309 USA. NR 4 TC 1 Z9 1 U1 2 U2 4 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD MAY 1 PY 1999 VL 6 BP 341 EP 343 DI 10.1107/S0909049598016537 PN 3 PG 3 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 212NA UT WOS:000081221700079 PM 15263301 ER PT J AU Gupta, JA Woicik, JC Watkins, SP Harrison, DA Crozier, ED Karlin, BA AF Gupta, JA Woicik, JC Watkins, SP Harrison, DA Crozier, ED Karlin, BA TI Layer perfection in ultrathin MOVPE-grown InAs layers buried in GaAs(001) studied by X-ray standing waves and photoluminescence spectroscopy SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 10th International Conference on XAFS (XAFS X) CY AUG 10-14, 1998 CL ILLINOIS INST TECHNOL, CHICAGO, ILLINOIS HO ILLINOIS INST TECHNOL DE X-ray standing waves; photoluminescence spectroscopy; InAs quantum wells ID MONOLAYER; GAAS AB Using the In-L fluorescence produced by normal-incidence X-ray standing waves, we have measured the layer perfection and positions of 1 and 1/2 monolayer (ML) InAs quantum wells buried in GaAs(001). Growth temperature effects were studied in a series of samples produced by metalorganic vapor phase epitaxy (MOVPE) at temperatures between 400 and 600 degrees C. The coherent position of the In atoms decreases with temperature in the 1 ML samples, and the optimal growth temperature is near 550 degrees C, as evidenced by the coherent position of 1.15+/-0.02, and the relatively high coherent fraction of 0.72+/-0.08. These results are corroborated by 1.6 K photoluminescence (PL) measurements in which the most sharp and intense In-excitonic emission is obtained from a sample grown at 530 degrees C. For the 1/2 ML samples, growth temperatures of 400 degrees C and 600 degrees C produce similar standing wave results: coherent positions of 1.09+/-0.02 and 1.10+/-0.02, coherent fractions of 0.75+/-0.10 and 0.74+/-0.11, respectively. However, PL reveals the higher temperature sample to be of far superior quality, due to excessive carbon incorporation at 400 degrees C. C1 Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. NIST, Gaithersburg, MD 20899 USA. RP Gupta, JA (reprint author), Simon Fraser Univ, Dept Phys, Burnaby, BC V5A 1S6, Canada. NR 8 TC 3 Z9 3 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD MAY 1 PY 1999 VL 6 BP 500 EP 502 DI 10.1107/S0909049598015581 PN 3 PG 3 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 212NA UT WOS:000081221700137 PM 15263359 ER PT J AU Ravel, B Cockayne, E Rabe, KM AF Ravel, B Cockayne, E Rabe, KM TI The local structure of ferroelectric Pb1-xGexTe SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 10th International Conference on XAFS (XAFS X) CY AUG 10-14, 1998 CL ILLINOIS INST TECHNOL, CHICAGO, ILLINOIS HO ILLINOIS INST TECHNOL ID ABSORPTION FINE-STRUCTURE; TRANSITION; PB AB The narrow band-gap semiconductor Pb1-xGexTe has a low-temperature ferroelectric rhombohedral phase whose average structure is a distorted rock salt structure. We have measured the Extended X-ray Absorption Fine-Structure spectra of Pb1-xGexTe with x approximate to 0.3 at the Ge and Te K edges and at the Pb-III edge. Guided by first-principles calculations, we create a model for the the local structure as a distortion from the ideal rock salt structure. By co-refining the spectra from these three edges, we demonstrate that the data are consistent with our fitting model. Our results show the power of using first-principles calculations in conjunction with EXAFS measurements to determine local structures in complex materials. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. Yale Univ, Dept Appl Phys, New Haven, CT 06520 USA. RP Ravel, B (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 11 TC 1 Z9 1 U1 3 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD MAY 1 PY 1999 VL 6 BP 567 EP 569 DI 10.1107/S0909049598015192 PN 3 PG 3 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 212NA UT WOS:000081221700160 PM 15263382 ER PT J AU Woicik, JC AF Woicik, JC TI Bond lengths in strained semiconductor alloys SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 10th International Conference on XAFS (XAFS X) CY AUG 10-14, 1998 CL ILLINOIS INST TECHNOL, CHICAGO, ILLINOIS HO ILLINOIS INST TECHNOL DE bond length; strain ID EPITAXIAL LAYERS; SOLID-SOLUTIONS; FINE-STRUCTURE; GA1-XINXAS AB The bond lengths in a series of strained, buried Ga1-xInxAs thin-alloy films grown coherently on GaAs(001) and InP(001) substrates have been determined by high-resolution extended x-ray absorption fine-structure and diffraction anomalous fine-structure measurements. Comparisons with random-cluster, valence-force field calculations demonstrate that the external in-plane epitaxial strain imposed by pseudomorphic growth opposes the natural bond-length distortions due to alloying. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Woicik, JC (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 12 TC 1 Z9 1 U1 0 U2 5 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD MAY 1 PY 1999 VL 6 BP 570 EP 572 DI 10.1107/S0909049598015556 PN 3 PG 3 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 212NA UT WOS:000081221700161 PM 15263383 ER PT J AU McDonald, MA Fox, CG AF McDonald, MA Fox, CG TI Passive acoustic methods applied to fin whale population density estimation SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID BALAENOPTERA-PHYSALUS; CALIFORNIA WATERS; DEPTH DEPENDENCE; 20-HZ SIGNALS; NOISE; MULTIPATH; PACIFIC; LOCALIZATION; ABUNDANCE; CETACEANS AB Assessing the size of cetacean populations in the open ocean has traditionally relied on visual surveys alone. The addition of acoustic monitoring can complement these surveys if reliable protocols can be formulated and calibrated with visual techniques. A study is presented to estimate fin whale population statistics based on near-continuous recording from a single hydrophone. Range to calling animals is estimated by transmission loss and multipath methods to provide a minimum population density estimate. Results are derived from recordings at a hydrophone site north of Oahu, Hawaii that have been the focus of earlier studies. The average calling whale density is 0.027 animals/1000 km(2), while the seasonal maximum calling whale density is about three times the average, or 0.081 animals/1000 km(2). Over 30 fixed hydrophone sites are available around the Worlds Oceans from which such statistics could be generated. (C) 1999 Acoustical Society of America. [S0001-4966(99)01005-X]. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Natl Ocean & Atmospher Adm, Pacific Marine Environm Lab, Newport, OR 97365 USA. RP McDonald, MA (reprint author), 2535 Sky View Lane, Laramie, WY 82070 USA. NR 44 TC 56 Z9 59 U1 2 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAY PY 1999 VL 105 IS 5 BP 2643 EP 2651 DI 10.1121/1.426880 PG 9 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 196LQ UT WOS:000080310200011 ER PT J AU Foster, K Fairburn, SL Leisure, RG Kim, S Balzar, D Alers, G Ledbetter, H AF Foster, K Fairburn, SL Leisure, RG Kim, S Balzar, D Alers, G Ledbetter, H TI Acoustic study of texture in polycrystalline brass SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID NEUTRON-DIFFRACTION; METALS AB Resonant ultrasound spectroscopy was used to measure the orthorhombic elastic constants of rolled, polycrystalline plates of Cu, Cu-5% Zn, and Cu-15% Zn. The experimental results were fit to theoretical expressions to determine the orientation-distribution coefficients W-400, W-420, and W-440. These coefficients are related to texture (the nonrandom orientation of crystallites). The experimental results were in good agreement with theory for the Cu and the Cu-15% Zn materials. The agreement was not as good for the more anisotropic Cu-5% Zn material, especially for the in-plane compressional constants C-11 and C-22. The ultrasonically derived W's were compared to those obtained from neutron measurements for the Cu-Zn alloys. Pole plots based on the two types of measurements, using W-400, W-420, and W-440, were in excellent agreement for the 15% Zn material, and in qualitative agreement for the 5% Zn material. The results support the idea that acoustic methods can be used to measure the low-order W's in polycrystalline materials. (C) 1999 Acoustical Society of America. [S0001-4966(99)00505-0]. C1 Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. NR 16 TC 8 Z9 8 U1 4 U2 11 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 EI 1520-8524 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAY PY 1999 VL 105 IS 5 BP 2663 EP 2668 DI 10.1121/1.426882 PG 6 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 196LQ UT WOS:000080310200013 ER PT J AU White, WH Macias, ES Vasconcelos, LAD Farber, RJ Mirabella, VA Green, MC Pitchford, ML AF White, WH Macias, ES Vasconcelos, LAD Farber, RJ Mirabella, VA Green, MC Pitchford, ML TI Tracking regional background in a haze attribution experiment SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID MOHAVE-POWER-PROJECT; GRAND-CANYON; TRANSPORT; PATTERNS AB Emissions from distant source areas are often imagined to provide a steady background to the emissions of whatever local sources are being studied. As part of Project MOHAVE in summer 1992, several air mass markers and an injected stack tracer were measured hourly near the Grand Canyon. Observed haze events generally coincided with transients in methylchloroform and water vapor, which we interpret as endemic tags for air from southern California and the subtropics. The results depict a dynamic regional background. C1 Washington Univ, Dept Chem, St Louis, MO 63130 USA. So Calif Edison, Rosemead, CA 91770 USA. Desert Res Inst, Las Vegas, NV 89119 USA. NOAA, Las Vegas, NV USA. RP White, WH (reprint author), Washington Univ, Dept Chem, 1 Brookings Dr, St Louis, MO 63130 USA. OI White, Warren H/0000-0001-7323-7867 NR 14 TC 4 Z9 4 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 1999 VL 49 IS 5 BP 599 EP 602 PG 4 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 194YN UT WOS:000080222500012 PM 28072302 ER PT J AU Krause, RF Luecke, WE French, JD Hockey, BJ Wiederhorn, SM AF Krause, RF Luecke, WE French, JD Hockey, BJ Wiederhorn, SM TI Tensile creep and rupture of silicon nitride SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 98th Annual Meeting of the American-Ceramic-Society CY APR 14-17, 1996 CL INDIANAPOLIS, IN SP Amer Ceram Soc ID GRAIN-BOUNDARY PHASE; CERAMIC MATERIALS; COMPRESSIVE CREEP; BEHAVIOR; STRESS; COMPONENTS; MECHANISMS; RELAXATION; RECOVERY; ALLOYS AB We have characterized the tensile creep, rupture lifetime, and cavitation behavior of a commercial, gas-pressure-sintered silicon nitride in the temperature range 1150 degrees to 1400 degrees C and stress range 70 to 400 MPa. Individual creep curves generally show primary, secondary, and tertiary creep, The majority of the primary creep is not recoverable. The best representation of the data is one where the creep rate depends exponentially on stress, rather than on the traditional power law. This representation also removes the need to break the data into high and low stress regimes. Cavitation of the interstitial silicate phase accompanies creep under all conditions, and accounts for nearly all of the measured strain. These observations are consistent with a model where creep proceeds by the redistribution of silicate phase from cavitating interstitial pockets, accommodated by grain-boundary sliding of silicon nitride. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Krause, RF (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 59 TC 43 Z9 43 U1 2 U2 6 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAY PY 1999 VL 82 IS 5 BP 1233 EP 1241 PG 9 WC Materials Science, Ceramics SC Materials Science GA 198WU UT WOS:000080447900019 ER PT J AU Lee, SK Lawn, BR AF Lee, SK Lawn, BR TI Contact fatigue in silicon nitride SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID CRACK-RESISTANCE CHARACTERISTICS; CYCLIC FATIGUE; HERTZIAN CONTACTS; POLYCRYSTALLINE CERAMICS; STRENGTH DEGRADATION; DAMAGE; ALUMINA; MICROSTRUCTURE; MECHANISM; FRICTION AB A study of contact fatigue in silicon nitride is reported. The contacts are made using WC spheres, principally in cyclic but also in static loading, and mainly in air but also in nitrogen and water. Damage patterns are examined in three silicon nitride microstructures: (i) fine (F)-almost exclusively fully-developed cone cracks; (ii) medium (M)-well developed but smaller cone cracks, plus modest subsurface quasi-plastic damage; (iii) coarse (C)-intense quasi-plastic damage, with little or no cone cracking. The study focuses on the influence of these competing damage types on inert strength as a function of number of contacts. In the F and M microstructures strength degradation is attributable primarily to chemically assisted slow growth of cone cracks in the presence of moisture during contact, although the M material shows signs of enhanced failure from quasi-plastic zones at large number of cycles. The C microstructure, although relatively tolerant of single-cycle damage, shows strongly accelerated strength losses from mechanical degradation within the quasi-plastic damage zones in cyclic loading conditions, especially in water. Implications concerning the design of silicon nitride microstructures for long-lifetime applications, specifically in concentrated loading, are considered. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Lee, SK (reprint author), Caterpillar Inc, Ctr Tech, Mossville, IL 61552 USA. NR 27 TC 29 Z9 30 U1 0 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 1999 VL 82 IS 5 BP 1281 EP 1288 PG 8 WC Materials Science, Ceramics SC Materials Science GA 198WU UT WOS:000080447900026 ER PT J AU Huang, HP AF Huang, HP TI Scale-dependent properties of optimal perturbations on a zonally varying barotropic flow SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ROSSBY-WAVE DYNAMICS; OPTIMAL EXCITATION; NORTHERN WINTER; COUETTE-FLOW; INSTABILITY; PREDICTABILITY; DISTURBANCES; MODEL; CIRCULATION; SIMULATIONS AB The scale-dependent characteristics of the optimal perturbations in a zonally asymmetric barotropic model are examined. The dependence of the optimal energy growth on the initial scale is investigated through the calculations of spectrally constrained optimal perturbations. Considering an optimization time of tau = 3 days and a basic state containing an idealized Asian jet, the optimal amplification factor generally increases with the decrease of the imposed initial scale. In the absence of diffusion, the most amplifying scale becomes the smallest scale in the model. An energetics analysis shows that the energy conversion in the optimal excitation process is dominated by the shear straining term, with a sharp increase in the scale of the perturbation accompanying the explosive energy growth. These results show the similarity between the optimally growing process in the zonally asymmetric system and the shear straining process in a parallel shear flow. Except when a small tau is considered or a sufficiently strong diffusion is used in the system, the optimal energy growth for small-scale disturbances sensitively depends on the zonally varying feature of the basic state. With tau = 3 days, the optimal amplification factors for small-scale disturbances are reduced significantly when the idealized Asian jet is shortened by only one-fifth. At the same time, those for medium- and large-scale disturbances are almost unaffected by the change of the basic state. The reasons for this contrast of the sensitivity property between the small and large scales are discussed. C1 Univ Illinois, Dept Atmospher Sci, Urbana, IL USA. RP Huang, HP (reprint author), Univ Colorado, NOAA, CIRES, Climat Diagnost Ctr, Campus Box 216, Boulder, CO 80309 USA. NR 32 TC 1 Z9 1 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 MAY 1 PY 1999 VL 56 IS 9 BP 1238 EP 1247 DI 10.1175/1520-0469(1999)056<1238:SDPOOP>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 190GG UT WOS:000079954000009 ER PT J AU Muschinski, A Chilson, PB Kern, S Nielinger, J Schmidt, G Prenosil, T AF Muschinski, A Chilson, PB Kern, S Nielinger, J Schmidt, G Prenosil, T TI First frequency-domain interferometry observations of large-scale vertical motion in the atmosphere SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SOUSY VHF RADAR; DOPPLER RADAR; LEE WAVES; WIND; TROPOSPHERE; VELOCITY; FRONT AB The spatiotemporal distribution of the vertical velocity at synoptic and subsynoptic scales is key to the patterns of weather and climate on earth. On these scales, the vertical velocity is on the order of one to a few centimeters per second, typically about three orders of magnitude smaller than typical horizontal wind velocities. Because of the smallness of large-scale vertical velocities relative to typical horizontal velocities, a direct observation of the large-scale vertical air velocity is extremely difficult. In a case study on observational material obtained during a 68-h experiment using the SOUSY very high frequency (VHF) radar in the Hart Mountains in Germany, the authors present the first intercomparison between three different sources of physical information that can provide large-scale vertical wind velocities: (i) the Doppler shifts observed with a vertically pointing VHF radar; (ii) the rates of change of the altitudes of refractive-index discontinuities as identified with frequency-domain interferometry (FDI), which is still a relatively unexplored technique in meteorology: and (iii) the output of a regional numerical weather prediction model (NWPM), which has been set up to model the meteorological situation during the observational period. There are several phenomena that have been known to possibly cause significant biases in mean vertical velocities retrieved from the Doppler shifts measured with vertically pointing clear-air VHF radars: (i) stationary or nonstationary gravity waves with vertical-velocity amplitudes up to the order of 1 m s(-1); (ii) stationary or horizontally advected tilted refractive-index discontinuities that are aspect sensitive in the VHF regime; and (iii) a correlation between the radar-reflectivity fluctuations and the vertical-velocity fluctuations within a vertically propagating gravity wave. On the basis of an intercomparison between the vertical velocities retrieved from (i) "standard Doppler" VHF radar observations, (ii) VHF FDI observations, and (iii) the NWPM output, the authors present first evidence that, under ideal conditions, VHF FDI can be used to directly monitor large-scale vertical motion. C1 Natl Ctr Atmospher Res, Atmospher Technol Div, Boulder, CO 80307 USA. Max Planck Inst Aeron, Katlenburg, Germany. Leibniz Univ Hannover, Inst Meteorol & Klimatol, Hannover, Germany. Amt Wehrgeophys, Traben, Germany. RP Univ Colorado, NOAA, CIRES, Environm Technol Lab, 325 Broadway,R-E-ET4, Boulder, CO 80303 USA. EM amuschinski@etl.noaa.gov NR 42 TC 18 Z9 18 U1 0 U2 0 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 MAY 1 PY 1999 VL 56 IS 9 BP 1248 EP 1258 DI 10.1175/1520-0469(1999)056<1248:FFDIOO>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 190GG UT WOS:000079954000010 ER PT J AU Gillen, G King, RL Chmara, F AF Gillen, G King, RL Chmara, F TI Development of a triplasmatron ion source for the generation of SF5+ and F- primary ion beams on an ion microscope secondary ion mass spectrometry instrument SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article AB A hot filament duoplasmatron ion source operating with argon has been modified by the addition of an enclosed expansion cup mounted to the extraction side of the duoplasmatron anode. Using sulfur hexafluoride (SF6) as a feed gas, this triplasmatron ion source has been used to generate SF5+ and F- primary ion beams for secondary ion mass spectrometry (SIMS). For positive primary ions, the current extracted from the source is composed of a series of SFx+ cluster ions (x = 1-5) with the SF5+ ion being the most intense. SF5+ currents of similar to 10-20 nA with a maximum of 40 nA are obtained at an extraction voltage of 10 kV. By applying a positive bias to the expansion cup, a localized secondary are discharge is initiated giving 200 nA-300 nA of SF5+ with a current density of 0.5 mA/cm(2). Depending on the operating parameters of the source, lifetimes of greater than 70 h have been achieved. For negative primary ions (with the cup removed), the current extracted from the source is primarily composed of F- ions with a maximum current of 3 mu A. The source can be briefly dosed with SF6 and will generate F- beams for 1-2 days without any additional gas being added. Evaluation of the SF5+ and F- ion beams for common SIMS applications demonstrates that these novel primary beams offer significant advantages for depth profiling, organic surface characterization and imaging. (C) 1999 American Vacuum Society. [S0734-2101(99)01003-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Peabody Sci, Peabody, MA 01960 USA. RP Gillen, G (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 11 TC 42 Z9 42 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAY-JUN PY 1999 VL 17 IS 3 BP 845 EP 852 DI 10.1116/1.581657 PG 8 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 197BD UT WOS:000080344000026 ER PT J AU Hill, SB Haich, CA Dunning, FB Walters, GK McClelland, JJ Celotta, RJ Craighead, HG Han, J Tanenbaum, DM AF Hill, SB Haich, CA Dunning, FB Walters, GK McClelland, JJ Celotta, RJ Craighead, HG Han, J Tanenbaum, DM TI Patterning of octadecylsiloxane self-assembled monolayers on Si(100) using Ar(P-3(0,2)) atoms SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID ELECTRON-BEAM LITHOGRAPHY; METASTABLE ARGON; SILICON; NANOLITHOGRAPHY; NANOSTRUCTURES; SURFACES; RESISTS; HELIUM; FIELD AB We report the use of metastable Ar(P-3(0,2)) atoms and a physical mask to pattern octadecylsiloxane self-assembled monolayers grown directly on silicon surfaces. The damage to the monolayer is confirmed using lateral force microscopy, changes in hydrophilicity, and x-ray photoelectron spectroscopy analysis. Metastable atom exposures sufficient to uniformly damage the monolayer should allow pattern transfer to the underlying Si(100) substrate following chemical and plasma etching. With optical manipulation of the incident metastable atoms, this technique could provide the basis for massively parallel nanoscale fabrication on silicon. (C) 1999 American Vacuum Society. [S0734-211X(99)04903-3]. C1 Rice Univ, Dept Phys, Houston, TX 77251 USA. Rice Univ, Rice Quantum Inst, Houston, TX 77251 USA. Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. Cornell Univ, Sch Appl & Engn Phys, Ithaca, NY 14853 USA. Pomona Coll, Dept Phys & Astron, Claremont, CA 91711 USA. RP Hill, SB (reprint author), Rice Univ, Dept Phys, Houston, TX 77251 USA. RI McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 NR 22 TC 17 Z9 17 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAY-JUN PY 1999 VL 17 IS 3 BP 1087 EP 1089 DI 10.1116/1.590699 PG 3 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 206AD UT WOS:000080853100034 ER PT J AU Veasey, DL Funk, DS Sanford, NA Hayden, JS Bendett, M AF Veasey, DL Funk, DS Sanford, NA Hayden, JS Bendett, M TI Laser arrays may provide DWDM measurement tool SO LASER FOCUS WORLD LA English DT Article AB High-power waveguide sources are more stable over time than commercially available semiconductor sources and can be pumped with diode lasers used to drive EDFAs. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. Schott Glass Technol, Duryea, PA 18642 USA. Northstar Photon, N Plymouth, MN 55447 USA. RP Veasey, DL (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 1 TC 1 Z9 1 U1 0 U2 0 PU PENNWELL PUBL CO PI NASHUA PA 98 SPIT BROOK RD, NASHUA, NH 03062-2801 USA SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD MAY PY 1999 VL 35 IS 5 BP 203 EP + PG 5 WC Optics SC Optics GA 195JB UT WOS:000080245900054 ER PT J AU Obarski, GE Hale, PD AF Obarski, GE Hale, PD TI How to measure relative intensity noise in lasers SO LASER FOCUS WORLD LA English DT Article AB Poisson noise on an optical signal and shot noise on a photocurrent are indistinguishable in detector output, but they can be determined separately from physical laws. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Obarski, GE (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. RI Hale, Paul/B-1737-2013 NR 7 TC 6 Z9 6 U1 0 U2 3 PU PENNWELL PUBL CO PI NASHUA PA 98 SPIT BROOK RD, NASHUA, NH 03062-2801 USA SN 0740-2511 J9 LASER FOCUS WORLD JI Laser Focus World PD MAY PY 1999 VL 35 IS 5 BP 273 EP + PG 4 WC Optics SC Optics GA 195JB UT WOS:000080245900063 ER PT J AU McCormick, MJ Fahnenstiel, GL AF McCormick, MJ Fahnenstiel, GL TI Recent climatic trends in nearshore water temperatures in the St. Lawrence Great Lakes SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID POTENTIAL CHANGES; THERMAL STRUCTURE; AIR TEMPERATURES; ATMOSPHERIC CO2; BOREAL LAKES; ICE-COVER; EL-NINO; MICHIGAN; PHYTOPLANKTON; PHOSPHORUS AB In the Great Lakes region, the observational evidence for climatic change has been primarily limited to changes in lake-ice conditions, with no long-term trends identified in water temperatures. Seven nearshore water intake sites (Bay City, Michigan; Green Bay, Wisconsin; Sault Ste. Marie, Michigan; St. Joseph, Michigan; Sandusky Bay, Ohio; Put-In-Bay, Ohio; and Erie, Pennsylvania) in the Great Lakes were chosen, and their data were examined for any climatic trends. Regression results on the annual mean temperatures showed varying support in favor of a warming trend at five of the seven sites. A new approach facilitated determination of the interannual variability in the timing of the 4 degrees C temperature of maximum density. Two of the three sites with data records extending back to the early part of this century (Sault Ste. Marie and Put-In-Bay, respectively) showed a 4- and a 6-h yr(-1) rate of increase in the maximum potential duration of summer stratification (DSS). Over the time span of these two data sets, this equates to a 14- and 18-d increase in the potential DSS, respectively. The rate of increase in the duration data was skewed, with most of the increase due to an earlier transition to springlike conditions. Finally, the data do not extend far enough back in time to know if these climatic trends are part of an unresolvable natural cycle or forced by anthropogenic activity. C1 NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. NOAA, Lake Michigan Field Stn, Muskegon, MI 49441 USA. RP McCormick, MJ (reprint author), NOAA, Great Lakes Environm Res Lab, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. NR 50 TC 69 Z9 69 U1 2 U2 7 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 1999 VL 44 IS 3 BP 530 EP 540 PG 11 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 196UQ UT WOS:000080326300006 ER PT J AU Seitzinger, SP Sanders, RW AF Seitzinger, SP Sanders, RW TI Atmospheric inputs of dissolved organic nitrogen stimulate estuarine bacteria and phytoplankton SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID NORTH-ATLANTIC OCEAN; CHESAPEAKE BAY; COASTAL WATERS; TROPHIC IMPLICATIONS; DEPOSITION; MARINE; EUTROPHICATION; CARBON; GROWTH; PRECIPITATION AB Atmospheric deposition is recognized as a potentially large source of inorganic nutrients to many ecosystems. In marine systems, where nitrogen (N) is the nutrient typically Limiting phytoplankton growth, rainwater is often a significant source of N. Although a considerable portion of atmospheric N deposition is in the form of organic N, only the inorganic N in rainwater has been considered by most previous studies. Laboratory experiments presented here indicate that dissolved organic nitrogen (DON) from rainwater can stimulate productivity of coastal marine bacteria and phytoplankton. A large percent of rainwater DON was potentially biologically available; 45-75% was rapidly utilized by the microorganisms. The magnitude of the response of bacterial and phytoplankton biomass to equivalent amounts of DON-N or ammonium-N was similar. However, the community composition of phytoplankton at the end of the experiment differed in treatments receiving DON and inorganic N. Diatoms and dinoflagellates accounted for >90% of the phytoplankton biomass in treatments receiving rainwater DON. In contrast, small (<2 mu m) monads accounted for >85% of the biomass in the treatments receiving ammonium. The results indicate that DON in rainwater can be an important source of N to ecosystems. C1 Rutgers State Univ, Inst Marine & Coastal Sci, Rutgers NOAA CMER Program, New Brunswick, NJ 08901 USA. Temple Univ, Dept Biol, Philadelphia, PA 19122 USA. RP Seitzinger, SP (reprint author), Rutgers State Univ, Inst Marine & Coastal Sci, Rutgers NOAA CMER Program, 71 Dudley Rd, New Brunswick, NJ 08901 USA. RI Sanders, Robert/C-1116-2011 OI Sanders, Robert/0000-0001-7264-1059 NR 68 TC 134 Z9 152 U1 3 U2 25 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 1999 VL 44 IS 3 BP 721 EP 730 PG 10 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 196UQ UT WOS:000080326300027 ER PT J AU Breitburg, DL Sanders, JG Gilmour, CC Hatfield, CA Osman, RW Riedel, GF Seitzinger, SB Sellner, KG AF Breitburg, DL Sanders, JG Gilmour, CC Hatfield, CA Osman, RW Riedel, GF Seitzinger, SB Sellner, KG TI Variability in responses to nutrients and trace elements, and transmission of stressor effects through an estuarine food web SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article; Proceedings Paper CT Symposium on the Effects of Multiple Stressors on Freshwater and Marine Ecosystems at the Annual Meeting of the American-Society-of-Limnology-and-Oceanography CY FEB, 1997 CL SAMTA FE, NEW MEXICO SP Amer Soc Limnol & Oceanog ID OYSTER CRASSOSTREA-VIRGINICA; DEPOSIT-FEEDING POPULATIONS; MACOMA-BALTHICA; PHYTOPLANKTON COMMUNITIES; EURYTEMORA-AFFINIS; CHESAPEAKE BAY; EUTROPHICATION; GROWTH; BACTERIA; LIMITATION AB Aquatic systems are increasingly exposed to multiple stressors from anthropogenic sources. These stressors can vary in the consistency and magnitude of responses they elicit in biota and in how the presence of additional stressors modifies their effects. Understanding how the biological environment and temporal dynamics influence responses to stressors, and how stressors interact, is important to predicting their effects in the natural environment. We examined temporal variability in responses of an experimental estuarine food web to elevated trace elements and nutrients, as well as non-additive effects of the combination of these two stressors. Experiments were conducted four times during spring through autumn 1996 in 20 1-m(3) mesocosms. We measured a range of system-, population-, and individual-level parameters to quantify responses of phytoplankton, bacterioplankton, heterotrophic nanoflagellates, copepods, fish, and benthic invertebrates to trace element and nutrient additions. The response to trace element additions was more variable both temporally and among phytoplankton and higher trophic level taxa than was the response to nutrient additions. Most taxa increased, either significantly or showed a trend toward increasing, in response to nutrient additions in all four mesocosm runs. In contrast, the direction as well as the magnitude of responses to trace element additions varied considerably among taxa and experimental runs. Two distinct types of nutrient x trace element interactions were important. First, temporal dynamics of nutrient ratios appeared to affect the temporal pattern of toxicity of trace elements to phytoplankton. Second, in the June mesocosm run when trace element additions reduced production, abundance, or growth of many organisms, these reductions were often proportionately greater in nutrient addition tanks than where no nutrients were added. Our results suggest that considerable temporal and taxonomic variation in responses to trace element loadings are likely to be seen in field settings even under constant loadings to the system and that trace elements may mask the magnitude of the response to high nutrient loadings in eutrophic systems. More generally, the presence of multiple stressors may either increase or dampen the temporal and spatial variability seen in aquatic systems, depending on the interactions among stressors and the influence of background environmental conditions and sensitive species on the expression of stressor effects. C1 Natl Acad Sci, Estuarine Res Ctr, St Leonard, MD 20685 USA. Rutgers State Univ, Cook Coll, Dept Ecol Evolut & Nat Resources, New Brunswick, NJ 08901 USA. Rutgers State Univ, NOAA, CMER Program, Inst Marine & Coastal Sci, New Brunswick, NJ 08901 USA. RP Breitburg, DL (reprint author), Natl Acad Sci, Estuarine Res Ctr, 10545 Mackall Rd, St Leonard, MD 20685 USA. RI Gilmour, Cynthia/G-1784-2010 OI Gilmour, Cynthia/0000-0002-1720-9498 NR 89 TC 73 Z9 77 U1 2 U2 27 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD MAY PY 1999 VL 44 IS 3 BP 837 EP 863 PN 2 PG 27 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 196UU UT WOS:000080326600010 ER PT J AU Lenihan, HS Micheli, F Shelton, SW Peterson, CH AF Lenihan, HS Micheli, F Shelton, SW Peterson, CH TI The influence of multiple environmental stressors on susceptibility to parasites: An experimental determination with oysters SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article; Proceedings Paper CT Symposium on the Effects of Multiple Stressors on Freshwater and Marine Ecosystems at the Annual Meeting of the American-Society-of-Limnology-and-Oceanography CY FEB, 1997 CL SANTA FE, NM SP Amer Soc Limnol & Oceanog ID PERKINSUS-MARINUS DISEASE; ACTIVE SUSPENSION-FEEDERS; CRASSOSTREA-VIRGINICA; CHESAPEAKE-BAY; EASTERN OYSTER; INFECTIOUS-DISEASE; MORTALITY; FLOW; FRAGMENTATION; DISTURBANCE AB A large-scale field experiment was used to test whether exposure to a suite of potential environmental factors (flow speed, temperature, salinity, and low dissolved oxygen) influences the level of parasitic infection of the oyster Crassostrea virginica. The parasite was the protozoan Perkinsus marinus, which has decimated populations of oysters in estuaries of North America. The environmental factors were considered stressors because they influence the physiological condition of either the host or parasite. Between December 1994 and July 1995, flow speed, temperature, salinity, dissolved oxygen concentration (DO), Perkinsus infection, and mortality of oysters were monitored across 24 experimental oyster reefs in the Neuse River estuary, North Carolina. Eight reef treatments were created consisting of an orthogonal combination of three factors: water depth (3 m vs. 6 m deep), reef height (2 m vs. 1 m tall), and position on reef (base vs, crest). Principal component analysis revealed that there was clear separation of environmental factors among reefs and that a majority of the variation (96.2%) among treatments could be explained by two principal component axes (PCs): one (24.3% of variation explained) was formed by flow and the other (71.9% of variation explained) by temperature, salinity, and DO. Oysters with the highest proportion of individuals infected (prevalence), highest intensity of infection, and highest mortality were located at the base of reefs, where flow speeds and food quality were lowest and sedimentation rates highest. However, there was no significant effect of hydrographic conditions on Perkinsus infection or mortality of oysters, despite large differences in mean salinity, DO, and exposure to hypoxia-anoxia. Temperature did not vary among treatments. Correlation of disease responses (infection prevalence and intensity, and mortality) with the first two PCs showed that these response variables were significantly (and negatively) correlated with flow only. Oysters in low flow were hypothesized to have:the greatest susceptibility to Perkinsus infection because of their poor physiological condition. The restoration of oyster reefs increases reef height and thus flow speeds (by elevating oysters higher above the boundary and by actively influencing flow), thereby reducing the negative effects of disease by restoring reef morphology to its natural size. C1 Univ N Carolina, Inst Marine Sci, Morehead City, NC 28557 USA. N Carolina Div Marine Fisheries, Morehead City, NC 28557 USA. RP Lenihan, HS (reprint author), NOAA, Natl Marine Fisheries Serv, Beaufort Lab, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 64 TC 83 Z9 84 U1 2 U2 14 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 MAY PY 1999 VL 44 IS 3 BP 910 EP 924 PN 2 PG 15 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 196UU UT WOS:000080326600015 ER PT J AU Rosel, PE Tiedemann, R Walton, M AF Rosel, PE Tiedemann, R Walton, M TI Genetic evidence for limited trans-Atlantic movements of the harbor porpoise Phocoena phocoena SO MARINE BIOLOGY LA English DT Article ID MITOCHONDRIAL CONTROL REGION; POPULATION-STRUCTURE; DANISH WATERS; DNA; NORTH; VARIABILITY; MORTALITY; PATTERNS AB In the North Atlantic, 14 regional subpopulations have been proposed for the harbor porpoise Phocoena phocoena (Linnaeus, 1758). To what degree these populations experience genetic interchange is relatively unknown, particularly on the larger scale of the North Atlantic as a whole. With the recent completion of several regional genetic studies on population structure of the harbor porpoise in the North Atlantic, came the opportunity to combine datasets in an effort to broaden the geographic scope of focus. Three datasets comprised of mitochondrial DNA control region sequences, representing the Northeast and Northwest Atlantic regions were pooled and reanalyzed to examine the degree of trans-Atlantic exchange among harbor porpoise populations, and to examine the evolutionary history of the species in the North Atlantic. The movement of harbor porpoises across the Atlantic appears to occur at a low level. Genetic variability in the Northeast Atlantic is significantly lower than in the Northwest Atlantic, and may indicate a more recent recolonization for the Northeast Atlantic. The star phylogeny of northeastern haplotypes, with a number of rare haplotypes closely related to the most abundant type, indicates a recent population expansion. A disjunction in haplotypic frequencies between the Northeast and Northwest Atlantic probably occurs east of Greenland, but the exact location and source of the disjunction has yet to be determined. C1 Univ New Hampshire, Dept Zool, Durham, NH 03824 USA. Univ Kiel, Inst Haustierkunde, D-24118 Kiel, Germany. Univ St Andrews, Sea Mammal Res Unit, St Andrews KY16 8LB, Fife, Scotland. RP Rosel, PE (reprint author), Natl Ocean Serv, 219 Ft Johnson Rd, Charleston, SC 29412 USA. NR 43 TC 28 Z9 30 U1 1 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD MAY PY 1999 VL 133 IS 4 BP 583 EP 591 DI 10.1007/s002270050498 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 200KT UT WOS:000080539500001 ER PT J AU Siewert, TA AF Siewert, TA TI The International Institute of Welding: Report on 1998 actions SO MATERIALS EVALUATION LA English DT Article C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Siewert, TA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 0 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 MAY PY 1999 VL 57 IS 5 BP 494 EP 498 PG 5 WC Materials Science, Characterization & Testing SC Materials Science GA 195GD UT WOS:000080241500003 ER PT J AU Krupka, J Derzakowski, K Tobar, M Hartnett, J Geyer, RG AF Krupka, J Derzakowski, K Tobar, M Hartnett, J Geyer, RG TI Complex permittivity of some ultralow loss dielectric crystals at cryogenic temperatures SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article DE complex permittivity; dielectric losses; whispering gallery modes; cryogenic measurements; microwave measurements; dielectric property measurements ID RESONATORS; RUTILE; SAPPHIRE AB Whispering gallery modes were used for very accurate permittivity and dielectric loss measurements of ultralow loss isotropic and uniaxially anisotropic single crystals. Several materials including sapphire, YAG, quartz, and SrLaAlO4 were measured. The total absolute uncertainty in the real part of permittivity tensor components was estimated to be +/-0.1%, limited principally by the uncertainty in sample dimensions. Imaginary parts of permittivities were measured with uncertainties of about 10%, limited by the accuracy of e-factor measurements of whispering gallery modes. It has been observed that, for most crystals, dielectric losses can be approximated by a power function of absolute temperature only in limited temperature ranges. At temperatures between 4-50 K, losses are often affected by impurities, which are always present in real crystals. C1 Inst Mikroelekt & Optoelekt PW, PL-00662 Warsaw, Poland. Inst Radioelekt PW, PL-00665 Warsaw, Poland. Univ Western Australia, Dept Phys, Nedlands, WA 6009, Australia. Natl Inst Stand & Technol, Radio Frequency Technol Div, Boulder, CO 80303 USA. RP Inst Mikroelekt & Optoelekt PW, Koszykowa 75, PL-00662 Warsaw, Poland. RI Hartnett, John/F-7037-2010; Tobar, Michael/C-9763-2009 OI Tobar, Michael/0000-0002-3139-1994 NR 22 TC 172 Z9 172 U1 2 U2 17 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 MAY PY 1999 VL 10 IS 5 BP 387 EP 392 DI 10.1088/0957-0233/10/5/308 PG 6 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 198LY UT WOS:000080426700008 ER PT J AU Santhiya, D Subramanian, S Natarajan, KA Malghan, SG AF Santhiya, D Subramanian, S Natarajan, KA Malghan, SG TI Adsorption and electrokinetic studies on alumina suspensions using poly(vinyl alcohol) SO MINERALS & METALLURGICAL PROCESSING LA English DT Article DE alumina; poly(vinyl alcohol); adsorption; electrokinetics; FTIR spectroscopy ID DOUBLE-LAYER; PARTICLES; POLYMER AB The adsorption of poly(vinyl alcohol) (PVA) of molecular weight 25,000 onto alumina was studied as a function of pH. The adsorption isotherms were also determined. The adsorption density increases with increasing pH, while the isotherms are rounded and of the low affinity type. Electrokinetic studies indicate that the electrophoretic mobilities are reduced in magnitude in proportion to the PVA concentration, without any shift in isoelectric-point (iep). This resembles the influence of an indifferent electrolyte. The calculated values of the free energy of adsorption between alumina and PVA are suggestive of hydrogen bonding. FTIR spectroscopic data provide additional evidence in support of hydrogen bonding. C1 Indian Inst Sci, Dept Met, Bangalore, Karnataka, India. Natl Inst Stand & Technol, Technol Serv, Gaithersburg, MD 20899 USA. RP Santhiya, D (reprint author), Indian Inst Sci, Dept Met, Bangalore, Karnataka, India. NR 30 TC 6 Z9 6 U1 0 U2 0 PU SOC MINING METALLURGY EXPLORATION INC PI LITTLETON PA 8307 SHAFFER PARKWAY, LITTLETON, CO 80127 USA SN 0747-9182 J9 MINER METALL PROC JI Miner. Metall. Process. PD MAY PY 1999 VL 16 IS 2 BP 51 EP 55 PG 5 WC Metallurgy & Metallurgical Engineering; Mining & Mineral Processing SC Metallurgy & Metallurgical Engineering; Mining & Mineral Processing GA 258WB UT WOS:000083861500010 ER PT J AU Pasch, RJ Avila, LA AF Pasch, RJ Avila, LA TI Atlantic hurricane season of 1996 SO MONTHLY WEATHER REVIEW LA English DT Article AB A summary of the 1996 Atlantic hurricane season is given, and the individual tropical storms and hurricanes are described. This was the second active year in a row with a large number of intense hurricanes. Hurricane Fran, which hit the coast of North Carolina, was the strongest system to make landfall, and also the most destructive. C1 NOAA, Trop Predict Ctr, Natl Hurricane Ctr, NWS, Miami, FL 33165 USA. RP Pasch, RJ (reprint author), NOAA, Trop Predict Ctr, Natl Hurricane Ctr, NWS, 11691 SW 17th St, Miami, FL 33165 USA. NR 9 TC 23 Z9 23 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 1999 VL 127 IS 5 BP 581 EP 610 DI 10.1175/1520-0493(1999)127<0581:AHSO>2.0.CO;2 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 194RW UT WOS:000080208200001 ER PT J AU Matthews, AJ Kiladis, GN AF Matthews, AJ Kiladis, GN TI The tropical-extratropical interaction between high-frequency transients and the Madden-Julian oscillation SO MONTHLY WEATHER REVIEW LA English DT Article ID ROSSBY-WAVE PROPAGATION; NORTHERN WINTER; WESTERN PACIFIC; CIRCULATION ANOMALIES; LIFE-CYCLE; TOGA COARE; CONVECTION; VARIABILITY; ATMOSPHERE; SYSTEMS AB The interaction between high-frequency transient disturbances and convection, and the Madden-Julian Oscillation (MJO), is investigated using NCEP-NCAR reanalysis and satellite outgoing longwave radiation data for 15 northern winters. During the phase of the MJO with enhanced convection over the East Indian Ocean and Indonesia, and suppressed convection over the South Pacific convergence zone, both the Asian-Pacific jet and the region of upper-tropospheric tropical easterlies over the warm pool are displaced westward. These changes in the basic state lead to a weaker or "leakier" waveguide in the Asian-Pacific jet, with a westward-displaced "forbidden" region of tropical easterlies, such that high-frequency transient waves propagate equatorward into the deep Tropics over the central Pacific near the date line. As these waves induce convection in the region of ascent and reduced static stability ahead of the upper-level cyclonic disturbances, there is an enhancement of high-frequency convective variability over the central Pacific intertropical convergence zone during this phase of the MJO. This enhanced high-frequency convective variability appears to project back onto intraseasonal timescales and forms an integral part of the slowly varying diabatic heating held of the MJO. In the opposite phase of the MJO, the Asian-Pacific jet is extended eastward and there is an almost continuous waveguide across the Pacific. Together with the expanded forbidden region of tropical easterlies over the warm pool, this leads to a more zonal propagation of high-frequency transients along the waveguide with less equatorward propagation, and hence reduced high-frequency convective variability over the tropical central Pacific. There is also evidence of high-frequency waves propagating into the Indian Ocean region at the beginning of the MJO cycle, which may be important in the initiation of intraseasonal convective anomalies there. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Matthews, AJ (reprint author), Monash Univ, CRC So Hemisphere Meteorol, 3rd Floor,Bldg 70,Wellington Rd, Clayton, Vic 3168, Australia. RI Matthews, Adrian/A-6444-2011 OI Matthews, Adrian/0000-0003-0492-1168 NR 43 TC 103 Z9 105 U1 1 U2 9 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 1999 VL 127 IS 5 BP 661 EP 677 DI 10.1175/1520-0493(1999)127<0661:TTEIBH>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 194RW UT WOS:000080208200005 ER PT J AU Yu, CK Jou, BJD Smull, BF AF Yu, CK Jou, BJD Smull, BF TI Formative stage of a long-lived mesoscale vortex observed by airborne Doppler radar SO MONTHLY WEATHER REVIEW LA English DT Article ID MIDLATITUDE SQUALL LINE; WARM-CORE VORTEX; CONVECTIVE SYSTEM; STRATIFORM PRECIPITATION; NUMERICAL-SIMULATION; KINEMATIC STRUCTURE; EXPERIMENT TAMEX; EVOLUTION; VORTICES; COMPLEX AB The formative stage of a long-lived mesoscale cyclonic vortex was captured by the NOAA P-3 aircraft as it investigated a developing mesoscale convective system (MCS) near the southeastern coast of Taiwan on 16 June 1987 during the Taiwan Area Mesoscale Experiment. The supporting environment of the mesovortex was characterized by an exceptionally moist atmosphere and moderate ambient vertical shear through a deep layer from the near surface to similar to 6 km, with much weaker shear and winds aloft. In addition, a pronounced low-level mesoscale shear/convergence zone, which resulted from the interaction of southeasterly flow with northeasterly Bow confined to the near-coast region, existed in the vicinity of the observed mesovortex. Composite three-dimensional wind fields derived via pseudo-dual-Doppler synthesis show the vortex had a horizontal diameter expanding from similar to 40 km to similar to 70 km in the lower to midtroposphere, respectively, and exhibited considerable tilt through this layer. Contrary to previously documented mesovortices, which have generally been fully developed and observed in the stratiform region of mature-to-decaying MCSs, the present vortex was intimately coupled to convective precipitation within this developing MCS. This study provides unique observational evidence that under appropriate environmental conditions a long-lasting mesovortex may originate in the convective region of an MCS. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Natl Taiwan Univ, Dept Atmospher Sci, Taipei 10764, Taiwan. Univ Washington, NOAA, Natl Severe Storms Lab, Seattle, WA 98195 USA. RP Yu, CK (reprint author), Univ Washington, Dept Atmospher Sci, Box 354235, Seattle, WA 98195 USA. RI Yu, Cheng-Ku/C-3066-2011; OI Yu, Cheng-Ku/0000-0002-5522-4998; JOU, BEN JONG DAO/0000-0001-5715-042X NR 46 TC 17 Z9 19 U1 0 U2 0 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 1999 VL 127 IS 5 BP 838 EP 857 DI 10.1175/1520-0493(1999)127<0838:FSOALL>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 194RW UT WOS:000080208200015 ER PT J AU Pratt, JR Nayfeh, AH AF Pratt, JR Nayfeh, AH TI Design and modeling for chatter control SO NONLINEAR DYNAMICS LA English DT Article DE chatter; vibration control; self-excited oscillations; machining ID DYNAMICS; TOOL AB Boring bars for single-point turning on a lathe are particularly susceptible to chatter and have been the subject of numerous studies. Chatter is, in general, caused by instability. Clearly, the cutting process can be limited to regions of known stable operation. However, this severely constrains the machine-tool operation and causes a decrease in productivity. The more aggressive approach is to attack the stability problem directly through application of vibration control. Here, we demonstrate a new biaxial vibration control system (VPI Smart Tool) for boring bars. We present the experimentally determined modal properties of the VPI Smart Tool and demonstrate how these properties may be used to develop models suitable for chatter stability analysis, simulation, and development of feedback compensation. A phenomenological chatter model that captures much of the rich dynamic character observed during experiments is presented. We introduce the notion that the mean cutting force changes direction as the width of cut increases due to the finite nose radius of the tool. This phenomenon is used to explain the progression from chatter that is dominated by motions normal to the machined surface at small widths of cut to chatter that is dominated by motions tangential to the machined surface at large widths of cut. We show experimental evidence to support our assertion that a biaxial actuation scheme is necessary to combat the tendency of the tool to chatter in both directions. We then present some preliminary theoretical results concerning the persistence of subcritical instability as we expand consideration to high-speed machining. C1 Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, Blacksburg, VA 24061 USA. RP Pratt, JR (reprint author), NIST, Mfg Engn Lab, Gaithersburg, MD 20899 USA. NR 33 TC 33 Z9 33 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0924-090X J9 NONLINEAR DYNAM JI Nonlinear Dyn. PD MAY PY 1999 VL 19 IS 1 BP 49 EP 69 DI 10.1023/A:1008322520352 PG 21 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 214BV UT WOS:000081308500004 ER PT J AU Eichmiller, FC Giuseppetti, AA Hoffman, KM Brajdic, DR Miksch, V Delorey-Lytle, JA AF Eichmiller, FC Giuseppetti, AA Hoffman, KM Brajdic, DR Miksch, V Delorey-Lytle, JA TI Microleakage of a consolidated silver direct filling material SO OPERATIVE DENTISTRY LA English DT Article AB Microleakage of an experimental direct filling material comprised of a chemically precipitated silver powder that had been surface treated with a dilute acid to promote cold welding upon consolidation was evaluated. Microleakage was compared to both dispersed-phase and spherical amalgam by use of an in vitro gas-diffusion method and in class 5 restorations placed in extracted human teeth. The effect of two cavity varnishes and two dentin adhesives as cavity liners on microleakage was also evaluated using extracted teeth. Microleakage of silver powder consolidated with dental instruments was less than that found with dental amalgam. The use of copal or polyamide cavity varnish resulted in the lowest combination of microleakage on dentin and enamel margins. C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Eichmiller, FC (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Bldg 224,Room A153, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [P50 DE09322] NR 8 TC 1 Z9 1 U1 0 U2 0 PU UNIV WASHINGTON PI SEATTLE PA SCHOOL DENTISTRY SM-57, SEATTLE, WA 98195 USA SN 0361-7734 J9 OPER DENT JI Oper. Dent. PD MAY-JUN PY 1999 VL 24 IS 3 BP 162 EP 171 PG 10 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 194VM UT WOS:000080215000006 PM 10530278 ER PT J AU Band, YB Julienne, PS Trippenbach, M AF Band, YB Julienne, PS Trippenbach, M TI Radio-frequency output coupling of the Bose-Einstein condensate for atom lasers SO PHYSICAL REVIEW A LA English DT Article ID DISPERSIVE NONLINEAR MEDIA; DYNAMICS; STATE; SCATTERING; PHOTOFRAGMENTATION; PROPAGATION; MOLECULES; FIELD; PHASE; TRAP AB We develop the quantum-mechanical description of output coupling of macroscopic coherent matter waves from a Bose-Einstein condensate (BEC) via a radio-frequency field in the pulsed and cw limits for both strong and weak field coupling. The theory is converted into a Fock state description to point out the stimulated (in Bose particle) nature of the output coupling. A useful analogy with the theory of molecular photodissociation is used to explain the various regimes of output coupling BECs using radiation sources. We present specific calculations of the rates of output coupling as a function of the number of Bose atoms in the condensate and the frequency, detuning, and intensity of the radio-frequency field. [S1050-2947(99)00805-7]. C1 Ben Gurion Univ Negev, Dept Chem & Phys, IL-84105 Beer Sheva, Israel. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Band, YB (reprint author), Ben Gurion Univ Negev, Dept Chem & Phys, IL-84105 Beer Sheva, Israel. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 40 TC 30 Z9 30 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 1999 VL 59 IS 5 BP 3823 EP 3831 DI 10.1103/PhysRevA.59.3823 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 197UB UT WOS:000080383100091 ER PT J AU Walser, R Williams, J Cooper, J Holland, M AF Walser, R Williams, J Cooper, J Holland, M TI Quantum kinetic theory for a condensed bosonic gas SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATION; HARTREE-FOCK THEORY; FINITE-TEMPERATURE; MASTER EQUATION; COLLECTIVE EXCITATIONS; TRAPPED GAS; ATOMS; FLUCTUATIONS; COLLISIONS; SIMULATION AB We present a kinetic theory for Bose-Einstein condensation of a weakly interacting atomic gas in a trap. Starting from first principles, we establish a Markovian kinetic description for the evolution towards equilibrium. In particular, we obtain a set of self-consistent master equations for mean fields, normal densities, and anomalous fluctuations. These kinetic equations generalize the Gross-Pitaevskii mean-field equations, and merge them consistently with a quantum-Boltzmann-equation approach. [S1050-2937(99)08505-4]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 48 TC 84 Z9 84 U1 1 U2 8 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD MAY PY 1999 VL 59 IS 5 BP 3878 EP 3889 DI 10.1103/PhysRevA.59.3878 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 197UB UT WOS:000080383100097 ER PT J AU Zheludev, A Maslov, S Shirane, G Tsukada, I Masuda, T Uchinokura, K Zaliznyak, I Erwin, R Regnault, LP AF Zheludev, A Maslov, S Shirane, G Tsukada, I Masuda, T Uchinokura, K Zaliznyak, I Erwin, R Regnault, LP TI Magnetic anisotropy and low-energy spin waves in the Dzyaloshinskii-Moriya spiral magnet Ba2CuGe2O7 SO PHYSICAL REVIEW B LA English DT Article ID FIELD; ANTIFERROMAGNET; COMMENSURATE; PHASE; SCATTERING; TRANSITION; ORBIT; MNSI AB Neutron-diffraction and inelastic-scattering experiments are used to investigate in detail the field dependence of the magnetic structure and low-energy spin-wave spectrum of the Dzyaloshinskii-Moriya helimagnet Ba2CuGe2O7. The results suggest that the previously proposed model for the magnetism of this compound (an ideal sinusoidal spin spiral, stabilized by isotropic exchange and Dzyaloshinskii-Moriya interactions) needs to be refined. Both recent and previously published data can be quantitatively explained by taking into account the Kaplan-Shekhtman-Entin-Wohlman-Aharony term, a special magnetic anisotropy term that was predicted to always accompany Dzyaloshinskii-Moriya interactions in insulators. [S0163-1829(99)01017-6]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Tokyo, Dept Appl Phys, Bunkyo Ku, Tokyo 1138656, Japan. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Ctr Etud Nucl Grenoble, Dept Rech Fondamentale Mat Condensee, Lab Magnetisme & Diffract Neutron, F-38054 Grenoble, France. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. PL Kapitza Phys Problems Inst, Moscow, Russia. RP Zheludev, A (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Zaliznyak, Igor/E-8532-2014; Maslov, Sergei/C-2397-2009 OI Zaliznyak, Igor/0000-0002-9886-3255; Maslov, Sergei/0000-0002-3701-492X NR 25 TC 43 Z9 43 U1 1 U2 18 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1999 VL 59 IS 17 BP 11432 EP 11444 DI 10.1103/PhysRevB.59.11432 PG 13 WC Physics, Condensed Matter SC Physics GA 272CA UT WOS:000084631900058 ER PT J AU Udovic, TJ Huang, Q Lynn, JW Erwin, RW Rush, JJ AF Udovic, TJ Huang, Q Lynn, JW Erwin, RW Rush, JJ TI Neutron-scattering study of the nuclear and magnetic structure of DyD3 and associated vibrational and magnetic excitations SO PHYSICAL REVIEW B LA English DT Article ID SWITCHABLE OPTICAL-PROPERTIES; LANTHANUM HYDRIDE FILMS; RARE-EARTH HYDRIDES; THEORETICAL PREDICTION; INSULATING YH3; YTTRIUM; DIFFRACTION; DYNAMICS; ORDER AB Neutron-diffraction and inelastic-scattering measurements of the hexagonal rare-earth trideuteride DyD3 were undertaken between 1.27 and 295 K. Rietveld-refined, P (3) over bar c 1-symmetric models of the diffraction data as well as the observed neutron vibrational spectra indicate that DyD3 is crystallographically isostructural with YD3 and HoD3 over the temperature range measured. Below T-N=3.33(4) K, the Dy sublattice becomes antiferromagnetically ordered, with the 5.25(4)mu(B) moment along the c direction. In addition, the first crystal-field excitation for the J= 15/2 Dy ion has been identified at 7.79(8) meV. [S0163-1829(99)02318-8]. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Udovic, TJ (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 33 TC 21 Z9 21 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 1 PY 1999 VL 59 IS 18 BP 11852 EP 11858 DI 10.1103/PhysRevB.59.11852 PG 7 WC Physics, Condensed Matter SC Physics GA 197HN UT WOS:000080359500036 ER PT J AU Grimm, HP Davis, SH McFadden, GB AF Grimm, HP Davis, SH McFadden, GB TI Steps, kinetic anisotropy, and long-wavelength instabilities in directional solidification SO PHYSICAL REVIEW E LA English DT Article ID MORPHOLOGICAL STABILITY; ABSOLUTE STABILITY; INTERFACE KINETICS; HYPERCOOLED MELT; BINARY ALLOY; EQUATION; GROWTH; FLOW AB We consider the effect of anisotropic interface kinetics on long-wavelength instabilities during the directional solidification of a binary alloy having a vicinal interface. Linear theory predicts that a planar solidification front is stabilized under the effect of anisotropy as long as the segregation coefficient is small enough, whereas a novel instability appears at high rates of solidification. Furthermore, the neutral stability curve, indicating the values of the principal control parameter (here the morphological number) for which the growth rate of a sinusoidal perturbation of a given wavelength changes its sign, is shown to have up to three branches, two of them combining to form an isola for certain values of the control parameters. We identify conditions for which linear stability theory predicts the instability of the planar interface to long-wavelength traveling waves. A number of distinguished limits provide evolution equations that describe the resulting dynamical behavior of the crystal-melt interface and generalize previous work by Sivashinsky, Brattkus, and Davis and Riley and Davis. Bifurcation analysis and numerical computations for the derived evolution equations show that the anisotropy is able to promote the tendency to supercritical bifurcation, and also leads to the development of strongly preferred interface orientations for finite-amplitude deformations. [S1063-651X(99)02605-7]. C1 Northwestern Univ, Dept Engn Sci & Appl Math, Evanston, IL 60208 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Grimm, HP (reprint author), Northwestern Univ, Dept Engn Sci & Appl Math, Evanston, IL 60208 USA. RI McFadden, Geoffrey/A-7920-2008; Davis, Stephen /B-7344-2009 OI McFadden, Geoffrey/0000-0001-6723-2103; NR 19 TC 0 Z9 0 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 1999 VL 59 IS 5 BP 5629 EP 5640 DI 10.1103/PhysRevE.59.5629 PN B PG 12 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 197TZ UT WOS:000080382900028 PM 11969546 ER PT J AU Zimmerli, GA Wilkinson, RA Ferrell, RA Moldover, MR AF Zimmerli, GA Wilkinson, RA Ferrell, RA Moldover, MR TI Electrostriction of a near-critical fluid in microgravity SO PHYSICAL REVIEW E LA English DT Article ID LIQUID CRITICAL-POINT; DIELECTRIC-CONSTANT; GRAVITY AB We used interferometry to measure the electric-field-induced (i.e., electrostrictive) increase of the density of sulfur hexafluoride(SF6) near its critical point. The results at three temperatures (T-c + 5.0mK, T-c + 10.0 mK, T-c + 30.0mK with T-c = 319 K) agree with a calculation based on the Clausius-Mossotti relation and the restricted cubic model equation of state. To measure electrostriction, an inhomogeneous electric field (less than or equal to 26 kV/cm) was applied to the SF6 sample by charging a fine wire that passed through it. These measurements were performed in microgravity so that the small electrostrictive density changes (less than or equal to 3.5% in this paper) would not be complicated by stratification of the fluid's density induced by the Earth's gravity. The predicted shifts of the critical temperature and density resulting fi-om the electric field were too small to detect. [S1063-651X(99)13405-6]. C1 Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. NASA, Lewis Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Zimmerli, GA (reprint author), Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RI Moldover, Michael/E-6384-2013 NR 24 TC 11 Z9 11 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAY PY 1999 VL 59 IS 5 BP 5862 EP 5869 DI 10.1103/PhysRevE.59.5862 PN B PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 197TZ UT WOS:000080382900049 PM 11969567 ER PT J AU Mitchell, TB Bollinger, JJ Huang, XP Itano, WM Dubin, DHE AF Mitchell, TB Bollinger, JJ Huang, XP Itano, WM Dubin, DHE TI Direct observations of the structural phases of crystallized ion plasmas SO PHYSICS OF PLASMAS LA English DT Article; Proceedings Paper CT 40th Annual Meeting of the Division of Plasma Physics of the American-Physical-Society CY NOV 16-20, 1998 CL NEW ORLEANS, LA SP Amer Phys Soc, Div Plasma Phys ID QUADRUPOLE STORAGE RING; ONE-COMPONENT PLASMA; LASER-COOLED IONS; COULOMB CRYSTAL; WIGNER-CRYSTAL; TRAPPED IONS; PENNING TRAP; DUSTY PLASMA; TRANSITIONS; THERMODYNAMICS AB Laser-cooled (9)Be(+) ions confined in a Penning trap were directly observed, and the images were used to characterize the structural phases of the ions. With the ions in two-dimensionally extended lattice planes, five different stable crystalline phases were observed, and the energetically favored structure could be sensitively tuned by changing the areal density of the confined ions. Qualitatively similar structural phase transitions occur or are predicted to occur in other planar single-component systems with a variety of interparticle interactions. Closed-shell structures were observed with small ion clouds that were spherical or prolate, and crystals with long-range order were observed in the centers of clouds with large numbers of ions. These experimental results are in good agreement with theoretical predictions for the strongly coupled one-component plasma. [S1070-664X(99)92605-8]. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Mitchell, TB (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. EM travis.mitchell@nist.gov NR 41 TC 35 Z9 37 U1 1 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAY PY 1999 VL 6 IS 5 BP 1751 EP 1758 DI 10.1063/1.873433 PN 2 PG 8 WC Physics, Fluids & Plasmas SC Physics GA 190ND UT WOS:000079969500010 ER PT J AU Migdall, A AF Migdall, A TI More on history of applied correlated-photon metrology SO PHYSICS TODAY LA English DT Letter C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Migdall, A (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 1 TC 1 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAY PY 1999 VL 52 IS 5 BP 95 EP 95 PG 1 WC Physics, Multidisciplinary SC Physics GA 192JU UT WOS:000080075900023 ER PT J AU Tan, NCB Balogh, L Trevino, SF Tomalia, DA Lin, JS AF Tan, NCB Balogh, L Trevino, SF Tomalia, DA Lin, JS TI A small angle scattering study of dendrimer-copper sulfide nanocomposites SO POLYMER LA English DT Article DE dendrimers; nanocomposites; SANS ID STARBURST DENDRIMERS; CASCADE POLYMERS; CHEMISTRY AB Dendrimers are a new class of three-dimensional, man-made molecules produced by an unusual synthetic route which incorporates repetitive branching sequences to create a unique novel architecture. Exceptional features of the dendritic architecture include a high degree of structural symmetry, a density gradient displaying an intra-molecular minimum value and a well defined number of terminal groups which may be chemically different from the interior. The combination of these features creates an environment within the dendrimer molecule which facilitates trapping of guest species. Recently, dendritic polymers have been used as soluble templates/unimolecular reactors from which nano-clusters of inorganic compounds or elements can be synthesized. The basic concept involves using dendrimers as hosts to preorganize small molecules or metal ions, followed by a simple in situ reaction which will immobilize and stabilize domains of atomic or molecular guest components (inorganic compounds as well as elemental metals). In one of these examples poly(amidoamine) (PAMAM) dendrimers have been used, to attract copper(II) ions inside the macromolecules where they are subsequently reacted with solubilized H2S to form metal sulfides. These organic/inorganic, dendrimer-based hybrid species have been termed 'nanocomposites' and display unusual properties. For example, solubility of the nanocomposites is determined by the properties of the host dendrimer molecules. This allows for solubilization of the inorganic guest compounds in environments in which they are inherently insoluble. Since it has been established that there is no covalent bond between host and guest, these observations suggest that the inorganics are physically and spatially restricted by the dendrimer shell. However, this structure has not been verified. In this investigation a preliminary understanding of the physical structure of these dendrimer-based nanocomposites was sought. A model system of PAMAM dendrimer-copper sulfide nanocomposites was studied in various stages of its formation using a combination of small angle X-ray and neutron scattering experiments. The results suggest that little perturbation of the dendritic species occurs on complexation, but indicate that a secondary super-molecular aggregation phenomena occurs within nanocomposite solutions. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 USA, Res Lab, AMSRL WM MA, APG, Aberdeen, MD 21005 USA. Michigan Mol Inst, Midland, MI 48640 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Oak Ridge Natl Labs, Oak Ridge, TN 37831 USA. RP Tan, NCB (reprint author), USA, Res Lab, AMSRL WM MA, APG, Bldg 4600, Aberdeen, MD 21005 USA. OI Balogh, Lajos/0000-0002-3115-0787 NR 30 TC 47 Z9 49 U1 0 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD MAY PY 1999 VL 40 IS 10 BP 2537 EP 2545 DI 10.1016/S0032-3861(98)00491-1 PG 9 WC Polymer Science SC Polymer Science GA 161LP UT WOS:000078290700008 ER PT J AU Snyder, CR Mopsik, FI AF Snyder, CR Mopsik, FI TI A precision capacitance cell for measurement of thin film out-of-plane expansion. II. Hygrothermal expansion SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID EPOXY-RESINS; MOISTURE ABSORPTION; THERMAL-EXPANSION; WATER; TRANSPORT; DIFFUSION AB The data reduction techniques necessary for utilizing the capacitance cell described previously by us for thickness measurements [C. R. Snyder and F. I. Mopsik, Rev. Sci. Instrum. 69, 3889 (1998)] in a humid environment are presented. It is demonstrated that our data reduction techniques provide thicknesses that are equivalent to those measured under dry conditions within the expected experimental uncertainty. The utility of this technique is demonstrated by the measurement of the hygrothermal expansion (swelling) of a bisphenol-A based epoxy with novolac hardener and fused silica filler. Our technique is shown to have a higher sensitivity than most current thermomechanical analysis techniques and is readily amenable to humid conditions. [S0034-6748(99)01705-0]. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Snyder, CR (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RI Snyder, Chad/B-4957-2008 OI Snyder, Chad/0000-0002-2916-9809 NR 32 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD MAY PY 1999 VL 70 IS 5 BP 2424 EP 2431 DI 10.1063/1.1149791 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 193AU UT WOS:000080113600036 ER PT J AU Gillen, G Roberson, S Ng, C Stranick, M AF Gillen, G Roberson, S Ng, C Stranick, M TI Elemental and molecular imaging of human hair using secondary ion mass spectrometry SO SCANNING LA English DT Article DE hair analysis; secondary ion mass spectrometry; surface analysis; molecular imaging ID SPECTROSCOPY; MICROSCOPY; ENERGY; FILMS; BEAM AB Secondary ion mass spectrometry (SIMS) is used to image the spatial distribution of elemental and molecular species on the surface and in cross sections of doped human hair using a magnetic sector SIMS instrument operated as an ion microprobe. Analysis of electrically insulating, non planar hair samples requires one of two different methods of charge compensation to be used depending on the polarity of the sputtered secondary ions. For detection of positive secondary ions, the hair is imaged using a similar to 0.5 mu m diameter, 19.5 keV impact energy, O- microbeam with no auxiliary electron bombardment. For detection of negative secondary ions, a similar to 0.2 mu m diameter, 14.5 keV impact energy Cs+ microbeam is used in conjunction with normal incidence, low-energy electron bombardment. Both of these methods allow submicrometer spatial resolution elemental and molecular secondary ion images to be obtained from hair samples without metallic coating of the sample surface prior to analysis. Several examples are presented that reflect potential application areas for these analytical methods. C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Colgate Palmol Co, Analyt Sci, Piscataway, NJ USA. RP Gillen, G (reprint author), NIST, Chem Sci & Technol Lab, 100 Bur Dr,Stop 8371, Gaithersburg, MD 20899 USA. NR 20 TC 15 Z9 15 U1 0 U2 2 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAY-JUN PY 1999 VL 21 IS 3 BP 173 EP 181 PG 9 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 206GE UT WOS:000080868300001 PM 10390863 ER PT J AU Gonzalez, FI AF Gonzalez, FI TI Tsunami! SO SCIENTIFIC AMERICAN LA English DT Article C1 NOAA, Pacific Marine Environm Lab, Ctr Tsunami Inundat Mapping Efforts, Seattle, WA 98115 USA. RP Gonzalez, FI (reprint author), NOAA, Pacific Marine Environm Lab, Ctr Tsunami Inundat Mapping Efforts, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 3 TC 12 Z9 12 U1 0 U2 3 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD MAY PY 1999 VL 280 IS 5 BP 56 EP 65 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 189MW UT WOS:000079910000025 ER PT J AU Ortega, C Woodward, B AF Ortega, C Woodward, B TI New Argos capabilities for global ocean monitoring SO SEA TECHNOLOGY LA English DT Article C1 CLS Argos, Sci Applicat, Toulouse, France. Serv Argos Inc, Largo, MD USA. NOAA, Washington, DC 20230 USA. RP Ortega, C (reprint author), CLS Argos, Sci Applicat, Toulouse, France. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD MAY PY 1999 VL 40 IS 5 BP 59 EP + PG 5 WC Engineering, Ocean SC Engineering GA 199LV UT WOS:000080484300007 ER PT J AU Bailey, SM Woods, TN Canfield, LR Korde, R Barth, CA Solomon, SC Rottman, GJ AF Bailey, SM Woods, TN Canfield, LR Korde, R Barth, CA Solomon, SC Rottman, GJ TI Sounding rocket measurements of the solar soft X-ray irradiance SO SOLAR PHYSICS LA English DT Article ID THERMOSPHERIC NITRIC-OXIDE; EUV FLUX MODEL; SILICON PHOTODIODES; EXTREME-ULTRAVIOLET; IONIZATION FREQUENCIES; PHOTOELECTRON FLUX; CYCLE-21 AB Measurements of the solar soft X-ray (XUV: 2 nm to 30 nm) irradiance were performed from a sounding rocket payload flown from White Sands Missile Range, New Mexico on 4 October 1993 and again on 3 November 1994. The soft X-ray instrumentation comprised of silicon photodiodes with thin films deposited directly onto their active areas. The deposited material and its thickness in conjunction with the sensitivity of an uncoated diode determine the passband and the sensitivity of these photometric devices. The measurements are interpreted in terms of appropriate SERF 1 (Hinteregger, Fukui, and Gilson, 1981) model solar spectra. It is found that the data are consistent with a solar spectrum that is on average approximately a factor of two times the model solar spectra. It is shown that the measured irradiances are in reasonable agreement with other experiments. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. Int Radiat Detectors, Torrance, CA 90505 USA. RP Bailey, SM (reprint author), Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RI Solomon, Stanley/J-4847-2012 OI Solomon, Stanley/0000-0002-5291-3034 NR 33 TC 14 Z9 15 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAY PY 1999 VL 186 IS 1-2 BP 243 EP 257 DI 10.1023/A:1005141503558 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 209ZV UT WOS:000081081300013 ER PT J AU Mearns, AJ Simecek-Beatty, D AF Mearns, AJ Simecek-Beatty, D TI Doing and publishing the small science of spill response SO SPILL SCIENCE & TECHNOLOGY BULLETIN LA English DT Editorial Material C1 NOAA, Off Response & Restorat, Seattle, WA 98115 USA. RP Mearns, AJ (reprint author), NOAA, Off Response & Restorat, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1353-2561 J9 SPILL SCI TECHNOL B JI Spill Sci. Technol. Bull. PD MAY PY 1999 VL 5 IS 2 BP 101 EP 102 DI 10.1016/S1353-2561(99)00038-9 PG 2 WC Engineering, Environmental; Engineering, Petroleum SC Engineering GA 198HX UT WOS:000080418900001 ER PT J AU Burlington, LB AF Burlington, LB TI Ten year historical perspective of the NOAA damage assessment and restoration program SO SPILL SCIENCE & TECHNOLOGY BULLETIN LA English DT Article AB The United States Oil Pollution Act of 1990 (OPA) was enacted to reduce the probability of oil spills in U.S. waters. A key provision of the legislation enables recovery of damages for restoration of injured natural resources and lost services due to oil spills. The National Oceanic and Atmospheric Administration (NOAA) de,eloped regulations that set out a process for determining the appropriate type and scale of restoration actions to accomplish this goal. The restoration plan developed through this process is the basis for an economic claim for natural resource damages. The regulations recognize that various methods, including environmental models, may be used in identifying and quantifying injuries to natural resources and losses of their services and in developing a restoration approach for these injuries, Rather than designating particular assessment measures, NOAA requires each trustee to decide which methodologies are appropriate for each incident, given its particular facts and circumstances. Any procedure chosen must meet the standards in the rule: it must provide information useful for determining restoration needed for an incident, the cost of the method must be commensurate with the quality and quantity of information it is expected to generate, and, of particular significance here, the method must be reliable and valid for the particular incident. This paper describes how methods are selected, how they might be used, and what legal standards would be applied should these methods be used as evidence in litigation, Published by Elsevier Science Ltd. C1 NOAA, Off Gen Counsel, Silver Spring, MD 20910 USA. RP Burlington, LB (reprint author), NOAA, Off Gen Counsel, Room 15132,1315 E W Highway, Silver Spring, MD 20910 USA. NR 6 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 1353-2561 J9 SPILL SCI TECHNOL B JI Spill Sci. Technol. Bull. PD MAY PY 1999 VL 5 IS 2 BP 109 EP 116 DI 10.1016/S1353-2561(98)00047-4 PG 8 WC Engineering, Environmental; Engineering, Petroleum SC Engineering GA 198HX UT WOS:000080418900003 ER PT J AU Davis, CB McNichols, RJ AF Davis, CB McNichols, RJ TI Simultaneous nonparametric prediction limits - Response SO TECHNOMETRICS LA English DT Editorial Material C1 Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Davis, CB (reprint author), Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD MAY PY 1999 VL 41 IS 2 BP 108 EP 112 PG 5 WC Statistics & Probability SC Mathematics GA 188EY UT WOS:000079834900006 ER PT J AU Vangel, MG AF Vangel, MG TI Simultaneous nonparametric prediction limits - Discussion SO TECHNOMETRICS LA English DT Editorial Material C1 Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Vangel, MG (reprint author), Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER STATISTICAL ASSOC PI ALEXANDRIA PA 1429 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0040-1706 J9 TECHNOMETRICS JI Technometrics PD MAY PY 1999 VL 41 IS 2 BP 108 EP 108 PG 1 WC Statistics & Probability SC Mathematics GA 188EY UT WOS:000079834900005 ER PT J AU Kayano, MT Kousky, VE AF Kayano, MT Kousky, VE TI Intraseasonal (30-60 day) variability in the global tropics: principal modes and their evolution SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID OUTGOING LONGWAVE RADIATION; 40-50 DAY OSCILLATION; ATMOSPHERIC ANGULAR-MOMENTUM; NORTHERN WINTER; CIRCULATION ANOMALIES; ZONAL WIND; CONVECTION; PACIFIC; HEMISPHERE; SUMMER AB The evolution of the 30-60 day intraseasonal (Madden-Julian) oscillation (MJO), during boreal winter and summer, is studied by means of extended empirical orthogonal function analyses. For both seasons, the patterns describe an eastward traveling large-scale oscillatory regime with a period of approximately 45 days. Several atmospheric variables display a zonal wavenumber one pattern approximately symmetric about the equator. The seasonal variation of the MJO is investigated, especially in terms of the intraseasonal variability of the tropical convection. We find that the latitudinal location of the largest outgoing longwave radiation anomalies is directly related to the seasonal meridional shifts of the tropical convection in the Indo-Australian and Central American-South American regions. In the eastern hemisphere, the MJO affects the monsoons over India during boreal summer and over Australia during austral summer. In the western hemisphere the MJO has the greatest impact on convection over Northeast Brazil during austral summer and over Central America during boreal summer. The MJO-related evolution of 925-hPa specific humidity patterns (not previously documented) show remarkable seasonal dependence. The boreal summer patterns contain a large-scale component quite similar to that shown in the sea level pressure patterns. The austral summer patterns show strong regional variability that might indicate the interactions of the MJO with deep tropical convection in certain areas, such as along the South Pacific Convergence Zone and over northern South America. C1 Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, SP, Brazil. Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD 20746 USA. RP Kayano, MT (reprint author), Inst Nacl Pesquisas Espaciais, Ave Astronautas 1758, BR-12227010 Sao Jose Dos Campos, SP, Brazil. NR 44 TC 39 Z9 41 U1 0 U2 10 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 1999 VL 51 IS 3 BP 373 EP 386 DI 10.1034/j.1600-0870.1999.t01-3-00003.x PG 14 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 208ZF UT WOS:000081021900003 ER PT J AU Manabe, S Stouffer, RJ AF Manabe, S Stouffer, RJ TI Are two modes of thermohaline circulation stable? SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID OCEAN-ATMOSPHERE MODEL; FRESH-WATER INPUT; YOUNGER DRYAS; TRANSIENT RESPONSES; GRADUAL CHANGES; CO2; SENSITIVITY; THERMOCLINE; EQUATION; INCREASE AB The standard version of the coupled ocean-atmosphere model developed at the Geophysical Fluid Dynamics Laboratory (GFDL) of NOAA has at least two stable equilibria. One has a realistic and active thermohaline circulation (THC) with sinking regions in the northern North Atlantic Ocean. The other has a reverse THC with extremely weak upwelling in the North Atlantic and sinking in the Circumpolar Ocean of the Southern Hemisphere. Although the model has the seasonal variation of insolation, the structure of these two stable equilibria are very similar to those of a previous GFDL model without the seasonal variation. It is noted that the inactive mode of the reverse THC mentioned above is not a stable equilibrium for another version of the same coupled model which has a large coefficient of vertical subgrid scale diffusion. Although the reverse THC cell was produced in the Atlantic Ocean by a massive discharge of freshwater, it began to transform back to the original direct TNC as soon as the freshwater discharge was terminated. It appears that there is a critical value of diffusivity, above which two stable equilibria do not exist. Based upon paleoceanographic evidence, we suggest that the stable state of the reverse THC mentioned above did not prevail during the cold periods of Younger Dryas event which occurred during the last deglacial period. Instead, it is likely that the THC weakened temporarily, but reintensified before it reached the state of the reverse THC with no deep water formation in the North Atlantic Ocean. C1 Inst Global Change Res, FRSGC, Tokyo, Japan. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Manabe, S (reprint author), Inst Global Change Res, FRSGC, Tokyo, Japan. NR 33 TC 87 Z9 87 U1 0 U2 7 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD MAY PY 1999 VL 51 IS 3 BP 400 EP 411 PG 12 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 208ZF UT WOS:000081021900005 ER PT J AU Toth, Z Szunyogh, I Kalnay, E Iyengar, G AF Toth, Z Szunyogh, I Kalnay, E Iyengar, G TI Comments on: "Notes on the appropriateness of 'bred modes' for generating initial perturbations" SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Letter ID QUASI-GEOSTROPHIC MODEL; SINGULAR VECTORS; VARIATIONAL ASSIMILATION; LYAPUNOV VECTORS; LORENZ SYSTEM; ERROR GROWTH; PREDICTABILITY; ENSEMBLE; PREDICTION; DISTURBANCES AB We are gratified by Errico and Langland's (EL, 1999) interest in the use of bred vectors (BVs) in ensemble forecasting. Since they offer detailed comments on only 2 of our papers related to breeding, we would like to bring attention to a number of other related papers that are nor referenced by EL. In addition to Toth and Kalnay 1997 (TK97), which discussed in detail properties of breeding and its operational implementation at NCEP, these papers cover mathematically-oriented studies (Smith, 1997; Smith and Gilmour, 1998), experiments with low- or intermediate-dimensional models (Houtekamer and Derome, 1994; Swanson et al., 1998; Noone and Simmonds, 1998), and the use and verification of ensemble forecasts with operational numerical weather prediction models (Rennick, 1995: Barker. 1998; Atger, 1999; Zhu et al., 1996; Toth et al., 1996, 1997, 1998). With respect to EL's comments, we agree with many of their points in which they restate important and basic information available from different sources. We read with interest about EL's ideas and experiments regarding the geostrophic balance (or lack of it) of the total energy based (TE) singular vectors (SVs). We are grateful to the authors for helping us find 2 minor inconsistencies in the paper by Szunyogh et al. (SKT, 1997). First, the cross section latitude in Fig. Ib of SKT (45 S) was accidentally omitted From the legend. And second, on page 206, SKT used the wrong phrase "sign" for distinguishing among the different phases of the leading LLV. At most other places, however, we believe that EL's criticisms are unjustified for 3 reasons. First, at several places EL erroneously attribute statements to us that we have not made in any of our papers. Second, EL, make statements, or form conclusions that, based on independent research, are incorrect or very questionable. Finally, at other places, EL make statements that are confusing. We believe that most of the misdirected, incorrect or confusing statements could have been avoided either by reading some of the published references, especially the TK97 paper mentioned above, or by informal discussions. For the sake of brevity, we address only the most relevant issues below, grouped by topic areas. C1 Natl Ctr Envirom Predict, EMC, Camp Springs, MD 20746 USA. Univ Oklahoma, Sch Meteorol, Norman, OK USA. RP Toth, Z (reprint author), Natl Ctr Envirom Predict, EMC, 5200 Auth Rd,Rm 207, Camp Springs, MD 20746 USA. EM Zoltan.Toth@noaa.gov RI Kalnay, Eugenia/F-4393-2010; Szunyogh, Istvan/G-9248-2012; Toth, Zoltan/I-6624-2015; OI Toth, Zoltan/0000-0002-9635-9194; Kalnay, Eugenia/0000-0002-9984-9906 NR 40 TC 8 Z9 8 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD MAY PY 1999 VL 51 IS 3 BP 442 EP 449 DI 10.1034/j.1600-0870.1999.t01-3-00008.x PG 8 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 208ZF UT WOS:000081021900008 ER PT J AU Gray, G AF Gray, G TI Covariances in multiplicative estimates SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID CATCH AB Multiplicative estimators, in which a quantity is calculated as the product of two or more estimated factors, are relatively common in fisheries work. Creel surveys and stock assessment data are two obvious examples. If the same multiplicative factor is used in several estimates, or if there is covariance between multiplicative factors, then covariances will be induced in the estimates produced. These covariances can be large in some instances. This paper reviews general results for the variance and covariance of products, provides estimators for the induced covariances in some common fisheries applications, and demonstrates the use of the estimators in some simplified examples. C1 Natl Marine Fisheries Serv, Fisheries Stat & Econ Div, Silver Spring, MD 20910 USA. RP Gray, G (reprint author), US FDA, Ctr Devices & Radiol Hlth, Off Surveillance & Biometr, Div Biostat, HFZ-542,1350 Piccard Dr, Rockville, MD 20850 USA. NR 11 TC 1 Z9 1 U1 2 U2 4 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 1999 VL 128 IS 3 BP 475 EP 482 DI 10.1577/1548-8659(1999)128<0475:CIME>2.0.CO;2 PG 8 WC Fisheries SC Fisheries GA 351WZ UT WOS:000089183600007 ER PT J AU Hartman, MD Baron, JS Lammers, RB Cline, DW Band, LE Liston, GE Tague, C AF Hartman, MD Baron, JS Lammers, RB Cline, DW Band, LE Liston, GE Tague, C TI Simulations of snow distribution and hydrology in a mountain basin SO WATER RESOURCES RESEARCH LA English DT Article ID FOREST ECOSYSTEM PROCESSES; ENERGY EXCHANGE; COMPLEX TERRAIN; CLIMATE CHANGE; GENERAL-MODEL; ALPINE REGION; SIERRA-NEVADA; BALANCE; ACCUMULATION; COLORADO AB We applied a Version of the Regional Hydro-Ecologic Simulation System (RHESSys) that implements snow redistribution, elevation partitioning, and wind-driven sublimation to Loch Vale Watershed (LVWS), an alpine-subalpine Rocky Mountain catchment where snow accumulation and ablation dominate the hydrologic cycle. We compared simulated discharge to measured discharge and the simulated snow distribution to photogrammetrically rectified aerial (remotely sensed) images. Snow redistribution was governed by a topographic similarity index. We subdivided each hillslope into elevation bands that had homogeneous climate extrapolated from observed climate. We created a distributed wind speed field that was used in conjunction with daily measured wind speeds to estimate sublimation. Modeling snow redistribution was critical to estimating the timing and magnitude of discharge. Incorporating elevation partitioning improved estimated timing of discharge but did not improve patterns of snow cover since wind was the dominant controller of areal snow patterns. Simulating wind-driven sublimation was necessary to predict moisture losses. C1 Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. US Geol Survey, Biol Resources Div, Ft Collins, CO USA. Univ New Hampshire, Complex Syst Res Ctr, Durham, NH USA. NOHRSC, Chanhassen, MT USA. Univ Toronto, Dept Geog, Toronto, ON M5S 1A1, Canada. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Hartman, MD (reprint author), Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. RI Baron, Jill/C-5270-2016 OI Baron, Jill/0000-0002-5902-6251 NR 54 TC 62 Z9 62 U1 0 U2 15 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 MAY PY 1999 VL 35 IS 5 BP 1587 EP 1603 DI 10.1029/1998WR900096 PG 17 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 190YG UT WOS:000079992400023 ER PT J AU Koren, VI Finnerty, BD Schaake, JC Smith, MB Seo, DJ Duan, QY AF Koren, VI Finnerty, BD Schaake, JC Smith, MB Seo, DJ Duan, QY TI Scale dependencies of hydrologic models to spatial variability of precipitation SO JOURNAL OF HYDROLOGY LA English DT Article; Proceedings Paper CT 5th Scientific Assembly of the International-Association-of-Hydrological-Sciences CY APR 28-29, 1997 CL RABAT, MOROCCO SP Int Assoc Hydrol Sci DE scale; radar; rainfall; hydrologic model; runoff ID RADAR RAINFALL; RUNOFF; SENSITIVITY; RESOLUTION AB This study is focused on analyses of scale dependency of lumped hydrological models with different formulations of the infiltration processes. Three lumped hydrological models of differing complexity were used in the study: the SAC-SMA model, the Oregon State University (OSU) model, and the simple water balance (SWB) model. High-resolution (4 x 4 km) rainfall estimates from the next generation weather radar (NEXRAD) Stage III in the Arkansas-Red river basin were used in the study. These gridded precipitation estimates are a multi-sensor product which combines the spatial resolution of the radar data with the ground truth estimates of the gage data. Results were generated from each model using different resolutions of spatial averaging of hourly rainfall. Although all selected models were scale dependent, the level of dependency varied significantly with different formulations of the rainfall-runoff partitioning mechanism. Infiltration-excess type models were the most sensitive. Saturation-excess type models were less scale dependent. Probabilistic averaging of the point processes reduces scale dependency, however, its effectiveness varies depending on the scale and the spatial structure of rainfall. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. RP Koren, VI (reprint author), NOAA, Natl Weather Serv, Off Hydrol, 1325 East West Highway, Silver Spring, MD 20910 USA. RI Duan, Qingyun/C-7652-2011 OI Duan, Qingyun/0000-0001-9955-1512 NR 28 TC 90 Z9 95 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD APR 30 PY 1999 VL 217 IS 3-4 BP 285 EP 302 DI 10.1016/S0022-1694(98)00231-5 PG 18 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 191PR UT WOS:000080031200010 ER PT J AU Chen, GD Cooks, RG Bunk, DM Welch, MJ Christie, JR AF Chen, GD Cooks, RG Bunk, DM Welch, MJ Christie, JR TI Partitioning of kinetic energy to internal energy in the low energy collision-induced dissociations of proton-bound dimers of polypeptides SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE energy partitioning; proton-bound dimers; kinetic method; peptide dissociation ID INFRARED RADIATIVE DISSOCIATION; SURFACE-INDUCED DISSOCIATION; TANDEM MASS-SPECTROMETRY; TARGET GAS EXCITATION; INDUCED DECOMPOSITION; ACTIVATION-ENERGIES; MOLECULAR-IONS; PHASE BASICITIES; POLYATOMIC IONS; SURVIVOR IONS AB Collision-induced dissociation (CID) of the proton-bound dimers of a set of pentapeptides (leucine enkephalin analogs) generated by electrospray ionization is studied as a function of collision energy under conditions of single collisions with argon, As the collision energy is increased, the abundances of the two protonated peptides become more similar, indicating an increase in internal energy deposition, The effective temperature (T(eff)) of the cluster ions is calculated by the kinetic method and found to increase approximately linearly with collision energy. Knowing the fragmentation thermochemistry, the ion internal energy is characterized using the kinetic method. The partitioning quotient for the conversion of laboratory kinetic energy into internal energy for these cluster ions is 2% to 5% in the 50 eV to 200 eV collision energy range. Average relative standard deviations of multiple measurements of partitioning quotients are around 15% and are mainly due to uncertainties in ion abundance ratios. Unimolecular dissociation Rice-Ramsperger-Kassel-Marcus (RRKM) theory is used to calculate the relationship between the fragment ion abundance ratio and the total internal energy of the cluster ions. Comparison of these data with experiment allows the energy partitioning behavior to be characterized independently and more accurately. The partitioning quotient obtained in this way ranges from 2 +/- 1.0% (uncertainty is the standard derivation of multiple measurements) to 5 +/- 1.0%. These data are consistent with either an impulsive collisional activation mechanism or with collision complex formation. (Int J Mass Spectrom 185/186/187 (1999) 75-90) (C) 1999 Elsevier Science B.V. C1 Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. La Trobe Univ, Sch Chem, Bundoora, Vic 3083, Australia. RP Cooks, RG (reprint author), Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. RI Cooks, R/G-1051-2015 OI Cooks, R/0000-0002-9581-9603 NR 70 TC 9 Z9 9 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD APR 29 PY 1999 VL 185 SI SI BP 75 EP 90 DI 10.1016/S1387-3806(98)14078-2 PG 16 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 188PV UT WOS:000079857900009 ER PT J AU Irikura, KK AF Irikura, KK TI Acetylacetonate (acac) anion in the gas phase: predicted structures, vibrational spectra, and photodetachment energies SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ab initio; anion; electron affinity (EA); vibrational spectrum; photoelectron spectrum ID PHOTOELECTRON-SPECTROSCOPY; NEGATIVE-IONS; PENTANE-2,4-DIONATE; THERMOCHEMISTRY; COMPLEXES; CLUSTERS AB The geometry and vibrational spectrum of the gas-phase acetylacetonate anion [acac(-); (CH(3)CO)(2)CH(-)] are predicted using ab initio molecular orbital theory. At the MP2/6-31+G**//HF/6-31+G* level there are three stable conformers. In order of increasing energy, they are (1) a C(s) structure with the carbonyl groups in an anti conformation, (2) a C(2) structure with the carbonyls pointed exo (about 21 kJ mol(-1) higher than 1), and (3) a C(2v) structure with the carbonyls endo (about 27 kJ mol(-1) higher than 1). The third, least stable conformation corresponds to the geometry found in moat beta-diketonate coordination complexes. These three conformations are separated by barriers of about 60 kJ mol(-1). The infrared spectra of 1 and 2 are quite similar, but that of the endo structure 3 features two strong peaks instead of only one in the 1400-1700 cm(-1) region. The enol (4) and di-enol (5) isomers are 60 kJ mol(-1) and 230 kJ mol(-1) respectively, less stable than structure 1. Vertical photodetachment of acac- can produce neutral acac in a few low-lying electronic states. At the spin-restricted B3LYP/6-31+G*//HF/6-31+G* level, the lowest vertical detachment energies are predicted to be 2.9, 2.9, 2.9, 2.1, and 1.2 eV for 1-5, respectively, with an estimated uncertainty 2 sigma = 0.2 eV. The corresponding adiabatic detachment energies (EA(o)) are predicted to be 2.8, 2.8, 2.8, 2.1, and 1.2 eV. The vibrational spectra of the neutral radicals are also predicted and the vibrational structure on the photodetachment spectra is discussed. C1 NIST, Phys & Chem Properites Div, Gaithersburg, MD 20899 USA. RP Irikura, KK (reprint author), NIST, Phys & Chem Properites Div, Gaithersburg, MD 20899 USA. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 32 TC 6 Z9 6 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD APR 29 PY 1999 VL 185 SI SI BP 577 EP 587 DI 10.1016/S1387-3806(98)14192-1 PG 11 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 188PV UT WOS:000079857900054 ER PT J AU Battin-Leclerc, F Kim, IK Talukdar, RK Portmann, RW Ravishankara, AR AF Battin-Leclerc, F Kim, IK Talukdar, RK Portmann, RW Ravishankara, AR TI Rate coefficients for the reactions of OH and OD with HCl and DCl between 200 and 400 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAUSSIAN-BASIS SETS; TRANSITION-STATE-THEORY; CORRELATED MOLECULAR CALCULATIONS; CHEMICAL-REACTION RATES; ATOMIC BASIS SETS; FIRST-ROW ATOMS; TUNNELING CALCULATIONS; COMPUTER-PROGRAM; DYNAMICS; TEMPERATURES AB Rate coefficients for the reaction of OH radical with HCl (k(1)) between 200 and 400 K, were measured to be 3.28 x 10(-17) T-1.66 exp [184/T] cm(3) molecule(-1) s(-1) by producing OH via pulsed laser photolysis and detecting it via laser induced fluorescence. The rate coefficients for the reactions of OH with DCl (k(2)), OD with HCl (k(3)), and OD with DCl (k(4)) were also measured using the same method to be k(2) = 2.9 x 10(-12) exp [-728/T], k(3) = 8.1 x 10(-18) T-1.85 exp [300/T], and k(4) = 2.5 x 10(-12) exp [-660/T] cm(3) molecule(-1) s(-1). k(1) - k(4) were computed for 200 < T < 400 K using the variational transition theory, including tunneling corrections, to be k(1) = 1.49 x 10(-16) T-1.35 exp [262/T], k(2) = 9.04 x 10(-20) T-2.34 exp [429/T], k(3) = 1.01 x 10(-16) T-1.4 exp[309/T], and k(4) = 1.64 x 10(-19) T-2.27 exp [385/T]cm(3) molecule(-1) s(-1), in reasonable agreement with experiments. They were also used to analyze the origin of the isotope effects. A two-dimensional chemical transport model calculation shows that our measured higher values of k(1) at low temperatures do not significantly alter the calculated ozone abundance, or its trend, in the stratosphere. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. San Diego State Univ, San Diego, CA 92186 USA. San Diego Supercomp Ctr, San Diego, CA 92186 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Ravishankara, AR (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Portmann, Robert/C-4903-2009; TALUKDAR, RANAJIT/G-4530-2013; Ravishankara, Akkihebbal/A-2914-2011 OI Portmann, Robert/0000-0002-0279-6087; TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 32 TC 27 Z9 27 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 APR 29 PY 1999 VL 103 IS 17 BP 3237 EP 3244 DI 10.1021/jp990177j PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 192DR UT WOS:000080063400013 ER PT J AU Yurovsky, VA Ben-Reuven, A Julienne, PS Band, YB AF Yurovsky, VA Ben-Reuven, A Julienne, PS Band, YB TI Counterintuitive transitions in multistate curve crossing involving linear potentials SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID LIGHT AB Two problems incorporating a set of horizontal linear potentials crossed by a sloped linear potential are solved analytically and compared with numerical results: (a) the case where boundary conditions are specified at the ends of a finite interval and (b) the case where the sloped linear potential is replaced by a piecewise-linear sloped potential and the boundary conditions are specified at infinity. In the approximation of small gaps between the horizontal potentials, an approach similar to the one used for the degenerate problem (Yurovsky V A and Ben-Reuven A 1998 J, Phys. B: At. Mel. Opt. Phys. 31 1) is applicable for both problems. The resulting scattering matrix has a form different from the semiclassical result obtained by taking the product of Landau-Zener amplitudes. Counterintuitive transitions involving a pair of successive crossings, in which the second crossing precedes the first one along the direction of motion, are allowed in both models considered here. C1 Tel Aviv Univ, Sch Chem, IL-69978 Tel Aviv, Israel. Natl Inst Stand & Technol, Atom Phys Div, Bethesda, MD 20889 USA. Ben Gurion Univ Negev, Dept Chem, IL-84105 Beer Sheva, Israel. Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel. RP Yurovsky, VA (reprint author), Tel Aviv Univ, Sch Chem, IL-69978 Tel Aviv, Israel. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 15 TC 14 Z9 14 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD APR 28 PY 1999 VL 32 IS 8 BP 1845 EP 1857 DI 10.1088/0953-4075/32/8/306 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 193UN UT WOS:000080155700008 ER PT J AU Bowling, DR Delany, AC Turnipseed, AA Baldocchi, DD Monson, RK AF Bowling, DR Delany, AC Turnipseed, AA Baldocchi, DD Monson, RK TI Modification of the relaxed eddy accumulation technique to maximize measured scalar mixing ratio differences in updrafts and downdrafts SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CARBON-ISOTOPE DISCRIMINATION; BOREAL FOREST ECOSYSTEMS; DECIDUOUS FOREST; ATMOSPHERIC CO2; FLUX MEASUREMENTS; RESPIRED CO2; 3-DIMENSIONAL SYNTHESIS; ISOPRENE FLUXES; REYNOLDS STRESS; SURFACE-LAYER AB A modification to the relaxed eddy accumulation (REA) flux measurement technique is proposed which maximizes the scalar mixing ratio difference in updrafts and downdrafts. This technique was developed with the goal of measuring the stable isotope (C-13/C-12 and O-18/O-16) ratios of updraft and downdraft air and thus the net fluxes of (OO2)-O-13-O-16 and (COO)-C-12-O-18-O-16. Current mass spectrometer precision is small relative to measured isotopic gradients in CO, in the Earth's boundary layer, and the conventional REA approach is likely to be ineffective. The new technique, which we refer to as hyperbolic relaxed eddy accumulation (HREA), uses the conditional sampling concept of hyperbolic hole analysis to control sampling of air during only those turbulent events which contribute most strongly to the flux. Instead of basing updraft/downdraft sampling decisions strictly on vertical wind velocity, CO2 mixing ratio ([CO2]) fluctuations or those of another scalar are also used. Simulations using 10-Hz data show that a wind-based/scalar-based sampling threshold can achieve a factor of 2.7 increase in scalar updraft/downdraft [CO2] differences over simple REA. During midday periods with strong photosynthetic fluxes, up/down [CO2] differences with HREA of 8-10 ppm are possible, compared with 3-5 ppm for the best conventional REA case. Corresponding isotopic differences can likely be resolved with current mass spectrometers using this approach. C1 Univ Colorado, Dept Environm Populat & Organism Biol, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Atmospher Technol Div, Boulder, CO 80307 USA. Natl Ocean & Atmospher Adm, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. RP Bowling, DR (reprint author), Univ Colorado, Dept Environm Populat & Organism Biol, Boulder, CO 80309 USA. EM bowling@rintintin.colorado.edu RI Baldocchi, Dennis/A-1625-2009 OI Baldocchi, Dennis/0000-0003-3496-4919 NR 59 TC 45 Z9 46 U1 3 U2 13 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 1999 VL 104 IS D8 BP 9121 EP 9133 DI 10.1029/1999JD900013 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600003 ER PT J AU Slonaker, RL Van Woert, ML AF Slonaker, RL Van Woert, ML TI Atmospheric moisture transport across the Southern Ocean via satellite observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER-VAPOR TRANSPORT; ANTARCTIC PRECIPITATION; SSM/I; PENINSULA; DATASET; WEST AB Meridional moisture transport across the Southern Ocean was measured using a combination of TIROS operational vertical sounder and special sensor microwave/imager satellite data from 1988. Satellite and radiosonde estimates of moisture flux compare favorably near Macquarie Island (54.5 degrees S, 158.9 degrees E). The zonally averaged, vertically integrated, moisture flux values across 50 degrees S and 60 degrees S are -31.8 and -15.2 kg m(-1) s(-1) respectively. Resulting moisture convergence for the 50 degrees-60 degrees S latitude band is 636 +/- 50 kg m(-2) yr(-1), about 50% larger than indicated by contemporary studies using radiosondes or atmospheric analyses. Within this latitude band the poleward moisture transport peaks in the South Pacific sector near 135 degrees E, with a secondary maximum in the Amundsen Sea sector close to 135 degrees W. There is a dramatic moisture flux discontinuity across the Antarctic peninsula and the tip of South America near 45 degrees W, with equatorward moisture transport at all latitudes in the Weddell Sea sector. A regional study of West Antarctica indicates large poleward moisture pur is accomplished through the Belingshausen and Amundsen Seas only. C1 NOAA, NESDIS, Off Res & Applicat, UCAR Visiting Sci Program, Camp Springs, MD 20746 USA. RP Slonaker, RL (reprint author), Raytheon ITSS Corp, 4400 Forbes Blvd, Lanham, MD 20703 USA. EM fmh@stx.com NR 44 TC 15 Z9 24 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 27 PY 1999 VL 104 IS D8 BP 9229 EP 9249 DI 10.1029/1999JD900045 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600009 ER PT J AU Hicke, J Tuck, A Vomel, H AF Hicke, J Tuck, A Vomel, H TI Lower stratospheric radiative heating rates and sensitivities calculated from Antarctic balloon observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WATER-VAPOR; ATMOSPHERIC FLUXES; COOLING RATES; POLAR VORTEX; SOUNDER DATA; OZONE HOLE; CLOUDS; MODEL; CIRCULATION; DEHYDRATION AB Temperature, water vapor, and ozone profiles from balloon soundings at McMurdo Station, Antarctica, during winter 1994 were used to calculate the diabatic heating rate in the lower stratosphere. These three variables represent the necessary inputs to a clear-sky radiative heating rate calculation, Accurate profiles of these variables without recourse to ancillary climatological databases provide a means of testing the importance of realistic water vapor and ozone distributions to the lower stratospheric heating rate. Water vapor at wavelengths greater than 17 mu m contributes as much cooling as CO2 in the lower stratosphere during winter. Dehydration begins in midwinter and causes a decrease in the cooling rate (increase in the heating rate) by 30%. Ozone depletion affects both longwave and shortwave heating rates in the altitude region where the ozone loss occurs. The longwave heating decreases by 0.3 K d(-1) (potential temperature) and is comparable in magnitude to that of the decrease in shortwave heating for a balloon sounding in early October. Significant longwave heating increases of 0.6 K d(-1) also occur above the region of ozone depletion as a result of higher penetration of upwelling radiation emitted by the surface. Sensitivity studies of the impact of tropospheric clouds at McMurdo show that the lower stratospheric heating rates can decrease by 0.08 to 0.26 K d(-1) (vertically averaged) (18 to 60%), depending on the cloud parameterization used. Time series of the calculated heating rate at McMurdo show the effects of dehydration, ozone loss, and the increase of the heating rate (decrease of the cooling rate) as the temperatures decrease and approach radiative equilibrium through the winter. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Hicke, J (reprint author), NOAA, Aeron Lab, 325 Broadway,R-E-AL6, Boulder, CO 80303 USA. EM jhicke@al.noaa.gov; tuck@al.noaa.gov; hvoemel@al.noaa.gov RI Tuck, Adrian/F-6024-2011; Hicke, Jeff/M-9677-2013 OI Tuck, Adrian/0000-0002-2074-0538; NR 35 TC 8 Z9 8 U1 0 U2 2 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 1999 VL 104 IS D8 BP 9293 EP 9308 DI 10.1029/1999JD900042 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600013 ER PT J AU Hicke, J Tuck, A AF Hicke, J Tuck, A TI Tropospheric clouds and lower stratospheric heating rates: Results from late winter in the Southern Hemisphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID COOLING RATES; POLAR VORTEX; OZONE; MODEL; RADIATION; SYSTEM; PARAMETERIZATION; BALANCE AB Tropospheric clouds can impact the radiative heating of the lower stratosphere substantially, though their effect over a winter has been estimated by previous studies to be small. In this study clouds were incorporated into radiative transfer calculations by matching computations of outgoing longwave radiation (OLR) with collocated satellite observations of OLR. Narrowband(cm(-1) resolution) heating rate calculations reveal that differences in clear and cloudy heating rates occur in the ozone 9.6 mu m band, where radiation exchange with the lower surface dominates the heating rate terms. By reducing the temperature of the emitting surface, clouds can decrease the heating rate by 0.6 K d(-1) (d theta/dt) at 450 K for single profile calculations and have the greatest impact when over-the warm, open ocean. Monthly mean calculations in the Southern Hemisphere show regions where heating rates decrease (cooling rates increase)by 0.2-0.3 K d-1 when clouds are added; these regions include areas that are equatorward of the sea ice edge but within the stratospheric polar vortex. Zonal mean heating rates display a maximum just poleward of the vortex edge during August and September 1994. Zonal monthly mean comparisons of the OLR-matched cloudy heating rates with those using a cloud climatology show that the climatology captures 50-75% of this decrease in heating rates compared to clear skies. Differences between zonal monthly means of the daily heating rate and heating rates computed using zonal monthly inputs are small, validating the use of mean radiative heating rates in two-dimensional monthly calculations. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. RP Hicke, J (reprint author), NOAA, Aeron Lab, 325 Broadway,R-E-AL6, Boulder, CO 80303 USA. EM jhicke@al.noaa.gov; tuck@al.noaa.gov RI Tuck, Adrian/F-6024-2011; Hicke, Jeff/M-9677-2013 OI Tuck, Adrian/0000-0002-2074-0538; NR 33 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 27 PY 1999 VL 104 IS D8 BP 9309 EP 9324 DI 10.1029/1999JD900043 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600014 ER PT J AU Schwarzkopf, MD Ramaswamy, V AF Schwarzkopf, MD Ramaswamy, V TI Radiative effects of CH4, N2O, halocarbons and the foreign-broadened H2O continuum: A GCM experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; COOLING RATES; WATER-VAPOR; STRATOSPHERIC OZONE; ATMOSPHERIC FLUXES; MIDDLE ATMOSPHERE; CARBON-DIOXIDE; ABSORPTION; CLIMATE; PARAMETERIZATION AB The simplified exchange approximation (SEA) method for calculation of infrared radiative transfer used for general circulation model (GCM) climate simulations at the Geophysical Fluid Dynamics Laboratory (GFDL) and other institutions, has been updated to permit inclusion of the effects of methane (CH4), nitrous oxide (N2O), halocarbons, and water-vapor-air molecular broadening (foreign broadening). The effects of CH4 and N2O are incorporated by interpolation of line-by-line (LBL) transmissivity calculations evaluated at standard species concentrations; halocarbon effects are calculated from transmissivities computed using recently measured frequency-dependent absorption coefficients. The effects of foreign broadening are included by adoption of the "CKD" formalism for the water vapor continuum [Clough et al., 1989]. For a standard midlatitude summer profile, the change in the net infrared flux at the model tropopause due to the inclusion of present-day concentrations of CH4 and N2O is evaluated to within similar to 5% of corresponding LBL results; the change in net flux at the tropopause upon inclusion of 1 ppbv of CFC-11, CFC-12, CFC-113, and HCFC-22 is within similar to 10% of the LBL results. Tropospheric heating rate changes resulting from the introduction of trace species (CH4, N2O, and halocarbons) are calculated to within similar to 0.03 K/d of the LBL results. Introduction of the CKD water vapor continuum causes LBL-computed heating rates to decrease by up to similar to 0.4 K/d in the upper troposphere and to increase by up to similar to 0.25 Kid in the midtroposphere; the SEA method gives changes within similar to 0.05 K/d of the LBL values. The revised SEA formulation has been incorporated into the GFDL "SKYHI" GCM. Two simulations (using fixed sea surface temperatures and prescribed clouds) have been performed to determine the changes to the model climate from that of a control calculation upon inclusion of (1) the trace species and (2) the foreign-broadened water vapor continuum. When the trace species are added, statistically significant warming (similar to 1 K) occurs in the annual-mean tropical upper troposphere, while cooling (similar to 1.5 K) is noted in the upper stratosphere and stratopause region. The changes are generally similar to annual-mean equilibrium calculations made using a radiative-convective model assuming fixed dynamical heating. The effects of the CKD water vapor continuum include cooling (similar to 1 K) in the annual-mean troposphere above similar to 6 km, with significant warming in the lower troposphere. When effects of both trace gases and the CKD continuum are included, the annual-mean temperature increases below similar to 5 km and cools between 5 and 10 km, indicating that continuum effects dominate in determining temperature changes in the lower and middle troposphere. Above, trace gas effects dominate, resulting in warming in the tropical upper troposphere and cooling in most of the middle atmosphere. Clear-sky outgoing longwave irradiances have been computed for observed European Centre for Medium-Range Weather Forecasting atmospheric profiles using three versions of the SEA formulation, including the effects of (1) water vapor, carbon dioxide, and ozone; (2) the above species plus present-day concentrations of the new trace species; (3) all of the above species plus the CKD H2O continuum. Results for all three cases are within similar to 10 W/m(2) of corresponding Earth Radiation Budget Experiment clear-sky irradiance measurements. The combined effect of trace gases and the CKD continuum result in a decrease of similar to 8 W/m(2) in the computed irradiances. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Schwarzkopf, MD (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. EM ds@gfdl.gov NR 40 TC 63 Z9 64 U1 0 U2 9 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 1999 VL 104 IS D8 BP 9467 EP 9488 DI 10.1029/1999JD900003 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600025 ER PT J AU Potosnak, MJ Wofsy, SC Denning, AS Conway, TJ Munger, JW Barnes, DH AF Potosnak, MJ Wofsy, SC Denning, AS Conway, TJ Munger, JW Barnes, DH TI Influence of biotic exchange and combustion sources on atmospheric CO2 concentrations in New England from observations at a forest flux tower SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CARBON-DIOXIDE AB Hourly data for concentrations and fluxes of CO2 at 30 m in Harvard Forest (Petersham, Massachusetts) are analyzed using linear modeling to obtain regionally representative CO2 concentrations at a continental site. The time series is decomposed into contributions due to regional combustion, local canopy exchange, monthly average regional biotic exchange (as modulated by the daily cycle of growth and decay of the planetary boundary layer (PBL)), and the regional monthly background concentration Attributions are derived using time series analysis, data for a tracer for combustion (CO or acetylene (C2H2)), and measurements of indicators of proximate canopy exchange (CO2 flux and momentum flux). Results are compared to observations at Cold Bay, Alaska. Combustion contributes on average 4-5 ppm to ambient CO2 at Harvard Forest in winter and 2-3 ppm in summer. Regional biotic emissions elevate daily mean CO2 by 4-6 ppm in winter, and the covariance of the biotic cycle of uptake and emission with PBL height enhances daily mean CO2 by 1-2 ppm in summer; minimum values in late afternoon average 10 ppm lower than at Cold Bay in summer. The study shows that regionally representative concentrations of CO2 can be determined at continental sites if suitable correlates (tracers, fluxes of CO2, and momentum) are measured simultaneously with CO2 itself. C1 Columbia Univ, Lamont Doherty Earth Observ, Dept Earth & Environm Sci, Palisades, NY 10964 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Hoffman Lab, Cambridge, MA 02138 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Potosnak, MJ (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Dept Earth & Environm Sci, Rt 9W, Palisades, NY 10964 USA. EM potosnak@ldeo.columbia.edu; scw@io.harvard.edu; denning@atmos.colorado.edu; tconway@cmdl.noaa.gov; jwm@io.harvard.edu; dhb@io.harvard.edu RI Denning, Scott/F-4974-2011; Munger, J/H-4502-2013 OI Denning, Scott/0000-0003-3032-7875; Munger, J/0000-0002-1042-8452 NR 17 TC 54 Z9 55 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 APR 27 PY 1999 VL 104 IS D8 BP 9561 EP 9569 DI 10.1029/1999JD900102 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600030 ER PT J AU Bateman, MG Marshall, TC Stolzenburg, M Rust, WD AF Bateman, MG Marshall, TC Stolzenburg, M Rust, WD TI Precipitation charge and size measurements inside a New Mexico mountain thunderstorm SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MESOSCALE CONVECTIVE SYSTEM; FIRST LIGHTNING FLASH; ELECTRIC-FIELD; STRATIFORM REGION; SQUALL LINE; AIRBORNE AB We measured the charge and size of precipitation particles with an instrumented free balloon in a convective mountain thunderstorm:over Langmuir Laboratory in central New Mexico. Using an instrument that measured precipitation charge from 2 to 220 pC and equivalent particle diameters from 0.6 to 3.8 mm, we deduced that (1) the charge of the main positive charge region is carried by cloud particles, the charge of the main negative charge region is carried by a mixture of negative charge bearing cloud particles and precipitation particles, and the charge of the lower positive charge region is carried almost entirely by precipitation; (2) there was a mixture of both polarities of precipitation charge at nearly all altitudes; (3) there was no relationship between precipitation charge and size; (4) our charge data appear to support the noninductive ice-ice collisional charging mechanism; and (5) the sign of charge carried by the precipitation reverses with ambient temperature. In comparing these data to previous measurements that were collected in New Mexico mountain thunderstorms with different instrumentation, we found that in most ways our precipitation charge data are similar to the previous measurements. In comparing these data with data that we previously collected in the trailing stratiform regions of mesoscale convective systems, we found that there are substantial differences in the precipitation charge data between these different cloud types. C1 Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. Langmuir Lab Atmospher Res, Socorro, NM USA. RP Bateman, MG (reprint author), Global Hydrol & Climate Ctr, 977 Explorer Blvd, Huntsville, AL 35806 USA. EM monte.bateman@msfc.nasa.gov; marshall@beauty1.phy.olemiss.edu; mstolzen@beauty1.phy.olemiss.edu; dave.rust@nssl.noaa.gov OI Stolzenburg, Maribeth/0000-0001-8773-8101 NR 29 TC 26 Z9 28 U1 0 U2 2 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 1999 VL 104 IS D8 BP 9643 EP 9653 DI 10.1029/1998JD200118 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 189UY UT WOS:000079925600037 ER PT J AU Zozulya, AA Diddams, SA AF Zozulya, AA Diddams, SA TI Dynamics of self-focused femtosecond laser pulses in the near and far fields SO OPTICS EXPRESS LA English DT Article ID VARYING ENVELOPE APPROXIMATION; NONLINEAR DISPERSIVE MEDIA; PROPAGATION; BREAKDOWN; RAMAN; AIR AB We investigate the propagation of femtosecond pulses in a nonlinear, dispersive medium at powers several times greater than the critical power for self focusing. The combined effects of diffraction, normal dispersion and cubic nonlinearity lead to pulse splitting. We show that detailed theoretical description of the linear propagation of the pulse from the exit face of the nonlinear medium (near field) to the measuring device (far field) is crucial for quantitative interpretation of experimental data. (C) 1998 Optical Society of America. C1 Worcester Polytech Inst, Dept Phys, Worcester, MA 01609 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Zozulya, AA (reprint author), Worcester Polytech Inst, Dept Phys, 100 Inst Rd, Worcester, MA 01609 USA. RI Diddams, Scott/L-2819-2013 NR 18 TC 12 Z9 12 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD APR 26 PY 1999 VL 4 IS 9 BP 336 EP 343 PG 8 WC Optics SC Optics GA 190MT UT WOS:000079968000001 PM 19396290 ER PT J AU Overholser, RW Wuttig, M Neumann, DA AF Overholser, RW Wuttig, M Neumann, DA TI Chemical ordering in Ni-Mn-Ga Heusler alloys SO SCRIPTA MATERIALIA LA English DT Article ID NI2MNGA SINGLE-CRYSTALS; SYSTEMS; STRESS C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, NIST, Ctr Neutron Res, Gaithersburg, MD USA. RP Overholser, RW (reprint author), Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NR 33 TC 98 Z9 99 U1 6 U2 21 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 23 PY 1999 VL 40 IS 10 BP 1095 EP 1102 DI 10.1016/S1359-6462(99)00080-9 PG 8 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 208GT UT WOS:000080983200002 ER PT J AU Brown, SS Talukdar, RK Ravishankara, AR AF Brown, SS Talukdar, RK Ravishankara, AR TI Reconsideration of the rate constant for the reaction of hydroxyl radicals with nitric acid SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TEMPERATURE-DEPENDENCE; + HNO3; KINETICS; OH; NO3; ABSORPTION AB We report rate coefficients for the reaction of OH with HNO3, k(1), between 10 and 500 Torr of He, SF6, N-2, and O-2 and at 10 different temperatures between 200 and 375 K. We generated OH via pulsed photolysis of HNO3 and monitored the [OH] temporal profile via pulsed laser induced fluorescence. Below 300 K the value of k(1) increases rapidly with decreasing temperature and depends on pressure. The pressure dependence of k(1) at low temperature is significantly larger than that obtained by extrapolation of the currently available data. The pressure and temperature dependence is most likely due to a competition between direct abstraction and reactive complex formation. A rate constant expression derived from such a mechanism gives a global fit for k(1) that is applicable to atmospheric conditions. The new rate constant alters the calculated NO2 to HNO3 ratio in the lower stratosphere. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem, Boulder, CO 80309 USA. RP Ravishankara, AR (reprint author), NOAA, Aeron Lab, R-E-AL2,325 Broadway, Boulder, CO 80303 USA. RI TALUKDAR, RANAJIT/G-4530-2013; Brown, Steven/I-1762-2013; Ravishankara, Akkihebbal/A-2914-2011 OI TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 31 TC 88 Z9 89 U1 0 U2 12 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 22 PY 1999 VL 103 IS 16 BP 3031 EP 3037 DI 10.1021/jp984721k PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189YK UT WOS:000079933700018 ER PT J AU Montzka, SA Butler, JH Elkins, JW Thompson, TM Clarke, AD Lock, LT AF Montzka, SA Butler, JH Elkins, JW Thompson, TM Clarke, AD Lock, LT TI Present and future trends in the atmospheric burden of ozone-depleting halogens SO NATURE LA English DT Article ID BACKGROUND OBSERVATIONS; TROPOSPHERIC ABUNDANCE; GROWTH-RATES; EMISSIONS; DECREASE; LIFETIME AB The burden of ozone-depleting chemicals in the lower atmosphere has been decreasing since 1994 as a result of the Montreal Protocol(1-3). Here we show how individual chemicals have influenced this decline, in order to estimate how the burden could change in the near future. Our measurements of atmospheric concentrations of the persistent, anthropogenic chemicals that account for most ozone-depleting halogens in today's stratosphere show that the decline stems predominantly from the decrease in the atmospheric load of trichloroethane (CH3CCl3), a previously common cleaning solvent. The influence of this chemical on the decline has now peaked, however, and will become much smaller over the next five to ten years. As this influence lessens, a decrease in the burden of ozone-depleting halogen will, be sustained only if emissions of other halocarbons fall. Although emissions of most gases regulated by the Montreal Protocol have decreased substantially over the past ten years (refs 4-11), emissions of the potent ozone-depleting gas CBrClF2 (halon-1211) have remained fairly constant during this period(12,29), despite stringent limits on production in developed countries since 1994. The consequent atmospheric accumulation of this halon is retarding the decline of ozone-depleting halogens in the atmosphere more than any other persistent gas. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, Boulder, CO 80309 USA. RP Montzka, SA (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. OI Montzka, Stephen/0000-0002-9396-0400 NR 29 TC 187 Z9 196 U1 3 U2 27 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 22 PY 1999 VL 398 IS 6729 BP 690 EP 694 DI 10.1038/19499 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 189RP UT WOS:000079920100045 ER PT J AU Van Engen, AG Diddams, SA Clement, TS AF Van Engen, AG Diddams, SA Clement, TS TI Dispersion measurements of water with white-light interferometry (vol 37, pg 5679, 1998) SO APPLIED OPTICS LA English DT Correction C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Van Engen, AG (reprint author), Univ Colorado, JILA, Campus Box 440, Boulder, CO 80309 USA. RI Clement, Tracy/A-8885-2008; Diddams, Scott/L-2819-2013 NR 2 TC 2 Z9 2 U1 0 U2 2 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 APR 20 PY 1999 VL 38 IS 12 BP 2499 EP 2499 DI 10.1364/AO.38.002499 PG 1 WC Optics SC Optics GA 186JJ UT WOS:000079725400021 ER PT J AU D'Sa, EJ Lohrenz, SE AF D'Sa, EJ Lohrenz, SE TI Theoretical treatment of fluorescence detection by a dual-fiber-optic sensor with consideration of sampling variability and package effects associated with particles SO APPLIED OPTICS LA English DT Article ID CHLOROPHYLL-A FLUORESCENCE; ABSORPTION-SPECTRA; LIGHT-ABSORPTION; PHYTOPLANKTON; PHOTOSYNTHESIS; BOUNDARY; OCEAN AB The characteristics of a dual-fiber-optic sensor for measurements of chlorophyll fluorescence in aquatic environments were evaluated with a theoretical model. Consideration was given to sampling variability and package effects associated with particles (e.g., phytoplankton cells). A numerical simulation was developed to approximate the optical geometry of the dual fiber-optic sensor that permitted a visual representation of the fluorescence distribution within the sensor sampling volume. A Monte Carlo simulation was used to evaluate sampling variability associated with the number and distribution of particles within the sampling volume. Relatively high coefficients of variation were associated with low particle concentrations, although with sufficient signal averaging the coefficient of variation was reduced to less than 20%. The influence of package effects and intracellular absorption of fluorescence was evaluated with a simplified form of the model that treated fluorescence as a linear function of particle density and assumed uniform particle composition, constant fluorescence cross-sectional yield, and sufficient averaging of the fluorescence signal. The model predicted decreasing fluorescence per unit of chlorophyll with increasing values of the product of particle diameter and intraparticle chlorophyll concentration. Experimental trends in size dependence of chlorophyll-fluorescence relationships were compared with predictions of the model. (C) 1999 Optical Society of America. C1 Univ So Mississippi, Stennis Space Ctr, Dept Marine Sci, Mississippi State, MS 39529 USA. RP D'Sa, EJ (reprint author), Natl Ocean & Atmospher Adm, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, E-RA3,Rm 711,5200 Auth Rd, Camp Springs, MD 20746 USA. EM edsa@nesdis.noaa.gov; steven.lohrenz@usm.edu OI Lohrenz, Steven/0000-0003-3811-2975 NR 30 TC 8 Z9 9 U1 0 U2 1 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 APR 20 PY 1999 VL 38 IS 12 BP 2524 EP 2535 DI 10.1364/AO.38.002524 PG 12 WC Optics SC Optics GA 186JJ UT WOS:000079725400026 PM 18319822 ER PT J AU Hintsa, EJ Weinstock, EM Anderson, JG May, RD Hurst, DF AF Hintsa, EJ Weinstock, EM Anderson, JG May, RD Hurst, DF TI On the accuracy of in situ water vapor measurements in the troposphere and lower stratosphere with the Harvard Lyman-alpha hygrometer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DIODE-LASER SPECTROMETER; HYDROGEN BUDGET; H2O; AIRCRAFT; DEHYDRATION; NIMBUS-7; ER-2; CH4 AB In an effort to better constrain atmospheric water vapor mixing ratios and to understand the discrepancies between different measurements of water vapor in the stratosphere and troposphere, we have carefully examined data from the Harvard Lyman-alpha photofragment fluorescence hygrometer, which has flown on the NASA ER-2 aircraft from 1992 through 1998. The instrument is calibrated in the laboratory before and after each deployment, and the calibration is checked by direct absorption measurements in the troposphere. On certain flights, the ER-2 flew level tracks during which water vapor varied by up to 80 ppmv, under nearly constant atmospheric conditions. These flights provide a stringent test of our calibration via direct absorption and indicate agreement to within 3%, During the 1997 Photochemistry of Ozone Loss in the Arctic Region In Summer (POLARIS) mission, our Lyman-alpha instrument was compared with a new diode laser hygrometer from the Jet Propulsion Laboratory. Overall agreement was 5% during the June/July deployment and 1% for potential temperatures of 490 to 540 K. The accuracy of our instrument is shown to be +/-5%, with an additional offset of at most 0.1 ppmv. Data from this instrument, combined with simultaneous measurements of CH4 and H-2, are therefore ideal for studies of the hydrogen budget of the lower stratosphere. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Hintsa, EJ (reprint author), Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02543 USA. RI Hurst, Dale/D-1554-2016 OI Hurst, Dale/0000-0002-6315-2322 NR 27 TC 51 Z9 51 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD APR 20 PY 1999 VL 104 IS D7 BP 8183 EP 8189 DI 10.1029/1998JD100110 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187NV UT WOS:000079793600012 ER PT J AU Hurst, DF Dutton, GS Romashkin, PA Wamsley, PR Moore, FL Elkins, JW Hintsa, EJ Weinstock, EM Herman, RL Moyer, EJ Scott, DC May, RD Webster, CR AF Hurst, DF Dutton, GS Romashkin, PA Wamsley, PR Moore, FL Elkins, JW Hintsa, EJ Weinstock, EM Herman, RL Moyer, EJ Scott, DC May, RD Webster, CR TI Closure of the total hydrogen budget of the northern extratropical lower stratosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU MEASUREMENTS; WATER-VAPOR; SEASONAL-VARIATIONS; H2O; WINTER; CH4; SPECTROMETER; TROPOSPHERE; DEHYDRATION; FOUNTAIN AB Methane (CH4), molecular hydrogen (H-2), and water vapor (H2O) were measured concurrently on board the NASA ER-2 aircraft during the 1995-1996 Stratospheric Tracers of Atmospheric Transport (STRAT) and 1997 Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) campaigns. Correlations between these three main hydrogen reservoirs in the northern extratropical lower stratosphere are examined to evaluate H2O production from CH4 and H-2 oxidation. The expected ratio of stratospheric H2O production (P-H2O) to CH4 destruction (L-CH4) = -1.973 +/- 0.003 is calculated from an evaluation of CH4 and H-2 oxidation reactions and the relationship between H-2 and CH4 mixing ratios measured during STRAT. Correlations between H2O and CH4 were tight and linear only for air masses with mean ages greater than or equal to 3.8 years, restricting this analysis predominantly to latitudes between 40 degrees and 90 degrees N and potential temperatures between 470 and 540 K. The mean observed Delta H2O/Delta CH4 (-2.15 +/- 0.18) is in statistical agreement with the expected P-H2O/L-CH4. The annual mean stratospheric entry mixing ratio for H2O calculated from this slope is 4.0 +/- 0.3 ppm. The quantity H2O + 2 . CH4 is quasi-conserved at 7.4 +/- 0.5 ppm in older air masses in the northern extratropical lower stratosphere. Significant departure of H2O + 2 . CH4 from the mean value is a sensitive indicator of processes which influence H2O without affecting CH4, such as dehydration in a polar vortex or near the tropical tropopause. No significant trend is observed in ER-2 aircraft data for H2O + 2 . CH4 in the lower stratosphere from 1993 through 1997. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Harvard Univ, Dept Chem & Chem Biol, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Hurst, DF (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RI Herman, Robert/H-9389-2012; Hurst, Dale/D-1554-2016 OI Herman, Robert/0000-0001-7063-6424; Hurst, Dale/0000-0002-6315-2322 NR 32 TC 34 Z9 34 U1 0 U2 7 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 20 PY 1999 VL 104 IS D7 BP 8191 EP 8200 DI 10.1029/1998JD100092 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187NV UT WOS:000079793600013 ER PT J AU Graham, DW Johnson, KTM Priebe, LD Lupton, JE AF Graham, DW Johnson, KTM Priebe, LD Lupton, JE TI Hotspot-ridge interaction along the Southeast Indian Ridge near Amsterdam and St. Paul islands: helium isotope evidence SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE helium; isotopes; mantle plumes; Southeast Indian Ridge; mid-ocean ridge basalts ID MIGRATING MIDOCEAN RIDGES; RODRIGUEZ TRIPLE JUNCTION; ICELAND MANTLE PLUME; KERGUELEN PLATEAU; OCEANIC BASALTS; GEOCHEMISTRY; LAVAS; SYSTEMATICS; ATLANTIC; ND AB We report new helium isotope analyses for basaltic glasses recovered along the Southeast Indian Ridge (SEIR) between longitudes 77 degrees E and 88 degrees E. In this region, the SEIR shoals to a depth less than 1800 m as it crosses the Amsterdam-St. Paul (ASP) plateau, Atop the plateau, where the average sample spacing is similar to 10 km, He-3/He-4 ratios range between 9.3 and 13.4 R-A (R-A = atmospheric ratio) with significant variability over short distances. Away from the plateau, ridge segments show a more restricted He-3/He-4 range, between 7 and 9 R-A. Elevated He-3/He-4 ratios on the plateau are evidence for a deep mantle plume component that has been injected into the sub-ridge mantle beneath the region. Ridge segments southeast of the plateau show lower He-3/He-4 (7.6-8.3 R-A) than segments to the northwest (8.3-9.0 R-A), suggesting either a systematically varying 'background contamination' of the MORE asthenosphere in the region, or localized input of a 'low He-3/He-4' component along the southeastern ridge segments, possibly derived from the distant Kerguelen hotspot. A double peak structure exists in the regional He-3/He-4 spatial distribution, because there is also a strong plume-derived He isotope signal which is offset from the shallowest, thickest section of the ridge. High He-3/He-4 ratios (up to 14.1 R-A) are present all along the ridge segment immediately to the northwest of the ASP plateau (segment H), where anomalies in K/Ti ratio are also observed. The high He-3/He-4 ratios persist to the northern end of segment H, beyond which they abruptly drop to MORE background levels, which apparently persist all the way to the Rodrigues Triple Junction. This pattern suggests that the high-He-3/He-4 ASP plume supplies a shallow north-northeastward mantle Bow toward adjacent portions of the SEIR. There is a systematic difference in He-3/He-4-K/Ti behavior between axial lavas from the ASP plateau and those from segment H, suggesting a higher He/Ti elemental abundance ratio in the plume source material beneath segment H compared to that beneath the ridge axis on the ASP plateau. These observations are consistent with a model in which plume material supplied to segment H is derived from the outer portions of the ASP plume, where removal of He (relative to Ti) has been less efficient than within the core of the plume located beneath the Amsterdam and St. Paul islands. These outer portions of the plume have lower temperatures and have undergone less partial melting, leading to a higher relative He/Ti ratio compared to the inner portions of the plume that feed portions of the sub-ridge mantle beneath the ASP plateau, (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Bishop Museum, Honolulu, HI 96817 USA. NOAA, Pacific Marine Environm Lab, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Graham, DW (reprint author), Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. EM dgraham@oce.orst.edu OI Graham, David/0000-0002-7411-1905 NR 70 TC 52 Z9 54 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD APR 15 PY 1999 VL 167 IS 3-4 BP 297 EP 310 DI 10.1016/S0012-821X(99)00030-8 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 183FE UT WOS:000079542900014 ER PT J AU Mills, MJ Toon, OB Solomon, S AF Mills, MJ Toon, OB Solomon, S TI A 2D microphysical model of the polar stratospheric CN layer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BALLOON-BORNE MEASUREMENTS; CONDENSATION NUCLEI; PARTICLE FORMATION; MIDDLE ATMOSPHERE; AEROSOL; ANTARCTICA; NUCLEATION; JANUARY; GASES; OZONE AB Each spring a layer of small particles forms between 20 and 30 km altitude in the polar regions. We present the first self-consistent explanation of the observed "CN layer" from a 2D microphysical model of sulfate aerosol. Our theory relies on photolysis of H2SO4 and SO3, consistent with recent laboratory measurements, to produce SO2 in the upper stratosphere and mesosphere. An additional source of SO2 may be required. Nucleation throughout the polar winter extends the top of the aerosol layer to higher altitudes, despite strong downward transport of ambient air. This may affect heterogeneous chemistry at the top of the aerosol layer in polar winter and spring. C1 Univ Colorado, Atmospher & Space Phys Lab, PAOS, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Mills, MJ (reprint author), Univ Colorado, Atmospher & Space Phys Lab, PAOS, Campus Box 392, Boulder, CO 80309 USA. RI Mills, Michael/B-5068-2010 OI Mills, Michael/0000-0002-8054-1346 NR 24 TC 35 Z9 35 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1999 VL 26 IS 8 BP 1133 EP 1136 DI 10.1029/1999GL900187 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 187NW UT WOS:000079793700033 ER PT J AU Gao, RS Fahey, DW Del Negro, LA Donnelly, SG Keim, ER Neuman, JA Teverovskaia, E Wennberg, PO Hanisco, TF Lanzendorf, EJ Proffitt, MH Margitan, JJ Wilson, JC Elkins, JW Stimpfle, RM Cohen, RC McElroy, CT Bui, TP Salawitch, RJ Brown, SS Ravishankara, AR Portmann, RW Ko, MKW Weisenstein, DK Newman, PA AF Gao, RS Fahey, DW Del Negro, LA Donnelly, SG Keim, ER Neuman, JA Teverovskaia, E Wennberg, PO Hanisco, TF Lanzendorf, EJ Proffitt, MH Margitan, JJ Wilson, JC Elkins, JW Stimpfle, RM Cohen, RC McElroy, CT Bui, TP Salawitch, RJ Brown, SS Ravishankara, AR Portmann, RW Ko, MKW Weisenstein, DK Newman, PA TI A comparison of observations and model simulations of NOx/NOy in the lower stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OZONE; RADICALS; SUMMER; NO2 AB Extensive airborne measurements of the reactive nitrogen reservoir (NOy) and its component nitric oxide (NO) have been made in the lower stratosphere. Box model simulations that are constrained by observations of radical and long-lived species and which include heterogeneous chemistry systematically underpredict the NOx (= NO + NO2) to NOy ratio. The model agreement is substantially improved if newly measured rate coefficients for the OH + NO2 and OH + HNO3 reactions are used. When included in 2-D models, the new rate coefficients significantly increase the calculated ozone loss due to NOx and modestly change the calculated ozone abundances in the lower stratosphere. Ozone changes associated with the emissions of a fleet of supersonic aircraft are also altered. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Aerospace Corp, Los Angeles, CA 90009 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Denver, Dept Engn, Denver, CO 80208 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Atmospher Environm Serv, Downsview, ON, Canada. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Atmospher & Environm Res Inc, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gao, RS (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Newman, Paul/D-6208-2012; Gao, Ru-Shan/H-7455-2013; Brown, Steven/I-1762-2013; Ravishankara, Akkihebbal/A-2914-2011; Ko, Malcolm/D-5898-2015; Fahey, David/G-4499-2013; Neuman, Andy/A-1393-2009; Salawitch, Ross/B-4605-2009; Portmann, Robert/C-4903-2009; Cohen, Ronald/A-8842-2011; Wennberg, Paul/A-5460-2012 OI Newman, Paul/0000-0003-1139-2508; Fahey, David/0000-0003-1720-0634; Neuman, Andy/0000-0002-3986-1727; Salawitch, Ross/0000-0001-8597-5832; Portmann, Robert/0000-0002-0279-6087; Cohen, Ronald/0000-0001-6617-7691; NR 18 TC 56 Z9 56 U1 0 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 APR 15 PY 1999 VL 26 IS 8 BP 1153 EP 1156 DI 10.1029/1999GL900162 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 187NW UT WOS:000079793700038 ER PT J AU Osterman, GB Sen, B Toon, GC Salawitch, RJ Margitan, JJ Blavier, JF Fahey, DW Gao, RS AF Osterman, GB Sen, B Toon, GC Salawitch, RJ Margitan, JJ Blavier, JF Fahey, DW Gao, RS TI Partitioning of NOy species in the summer Arctic stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NITROGEN; OH AB Volume mixing ratio profiles of the quantitatively significant NOy species NO, NO2, HNO3, HNO4, ClNO3 and N2O5 were measured remotely from 8 to 38 km by the JPL MkIV FTIR solar absorption spectrometer during balloon flights from Fairbanks, Alaska (64.8 degrees N, 147.6 degrees W) on May 8 and July 8, 1997. The observed ratio of NO, (NO+NO2) to NOy (total reactive nitrogen) is 10 to 30% greater than calculated by a steady state model using standard photochemistry constrained by MkIV measurements of long lived precursors (e.g., H2O, CH4, CO and N2O) and SAGE II aerosol surface area. The persistence of this discrepancy to 38 km altitude suggests that processes involving aerosols, such as the reduction of HNO3 on the surface of soot particles, cannot be the sole explanation. The most likely resolution to this discrepancy is that the rate of NO2+OH +M-->HNO3+M (the dominant sink of NOx in the Arctic stratosphere during times of near continuous solar illumination) is significantly slower than the currently recommended rate. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Osterman, GB (reprint author), CALTECH, Jet Prop Lab, MS 183-601,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Salawitch, Ross/B-4605-2009; Gao, Ru-Shan/H-7455-2013; Fahey, David/G-4499-2013 OI Salawitch, Ross/0000-0001-8597-5832; Fahey, David/0000-0003-1720-0634 NR 18 TC 42 Z9 42 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 15 PY 1999 VL 26 IS 8 BP 1157 EP 1160 DI 10.1029/1999GL900166 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 187NW UT WOS:000079793700039 ER PT J AU Allee, RJ Johnson, JE AF Allee, RJ Johnson, JE TI Use of satellite imagery to estimate surface chlorophyll a and Secchi disc depth of Bull Shoals Reservoir, Arkansas, USA SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SPECTRAL-RESOLUTION RADIOMETER; TURBID INLAND WATERS; THEMATIC MAPPER; LAKE KINNERET; SUSPENDED SEDIMENTS; QUALITY; PHYTOPLANKTON; REFLECTANCE; AIRCRAFT; MSS AB Landsat Thematic Mapper data were acquired for four flyby dates that coincided with field data collection of chlorophyll a and Secchi disc depth for Bull Shoals Reservoir, Arkansas, USA. Predictive models were developed for chlorophyll a from July 1994 (R-2 = 0.80) and December 1994 (R-2 = 0.84) data and for Secchi disc depth (R-2 = 0.96) from February 1995 data. These models were then tested using historic chlorophyll a data compiled from the previous ten years. The July 1994 model satisfactorily predicted chlorophyll a levels in six of the ten years and this improved to five out of five years when only summer seasons were considered. Phytoplankton analyses suggested an influence on algorithm development with respect to species composition at the time of satellite flyby. C1 Univ Arizona, Dept Biol Sci, Arkansas Cooperat Fish & Wildlife Res Unit, Tucson, AZ 85721 USA. RP Allee, RJ (reprint author), NOAA, Natl Marine Fisheries Serv, Off Habitat Conservat, 1315 EW Highway, Silver Spring, MD 20910 USA. NR 38 TC 46 Z9 57 U1 0 U2 10 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 APR 15 PY 1999 VL 20 IS 6 BP 1057 EP 1072 DI 10.1080/014311699212849 PG 16 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 193DC UT WOS:000080119700002 ER PT J AU Sobolewski, MA Olthoff, JK Wang, YC AF Sobolewski, MA Olthoff, JK Wang, YC TI Ion energy distributions and sheath voltages in a radio-frequency-biased, inductively coupled, high-density plasma reactor SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RADIOFREQUENCY REFERENCE CELL; ARGON GLOW-DISCHARGES; PARALLEL-PLATE; RF DISCHARGES; ANGULAR-DISTRIBUTIONS; PROBE MEASUREMENTS; PLANAR SYSTEM; BOMBARDMENT; HELICON; ELECTRODES AB Ion energy distributions were measured at a grounded surface in an inductively coupled, high-density plasma reactor for pure argon, argon-helium, and argon-xenon discharges at 1.33 Pa (10 mTorr), as a function of radio-frequency (rf) bias amplitude, rf bias frequency, radial position, inductive source power, and ion mass. The ground sheath voltage which accelerates the ions was also determined using capacitive probe measurements and Langmuir probe data. Together, the measurements provide a complete characterization of ion dynamics in the sheath, allowing ion transit time effects to be distinguished from sheath impedance effects. Models are presented which describe both effects and explain why they are observed in the same range of rf bias frequency. [S0021-8979(99)03808-6]. C1 NIST, Gaithersburg, MD 20899 USA. RP Sobolewski, MA (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 54 TC 72 Z9 73 U1 4 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 3966 EP 3975 DI 10.1063/1.370298 PN 1 PG 10 WC Physics, Applied SC Physics GA 188LN UT WOS:000079848600005 ER PT J AU Chowdary, KM Giri, AK Pellerin, K Majetich, SA Scott, JHJ AF Chowdary, KM Giri, AK Pellerin, K Majetich, SA Scott, JHJ TI Annealing effects on the coercivity of SmCo5 nanoparticles SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MAGNETIZATION REVERSAL; MAGNETS AB The enhanced coercivity of ball milled nanoparticles of SmCo5 has been attributed to the reduced particle size, but the milling process introduces additional strain which can also affect the coercivity. Here the effects of size and strain are decoupled from each other using a combination of x-ray diffraction, electron microscopy, and coercivity measurements. Ball milled SmCo5 nanoparticles were annealed under different temperature, time, and atmospheric conditions to minimize the strain without chemically altering the sample, and with minimal grain growth and sintering. X-ray diffraction was used to determine if phase changes had occurred, and to monitor the average grain size and strain. From scanning electron microscopy the log-normal size distributions were found and no evidence of sintering was revealed. The sample coercivities were measured by superconducting quantum interference device following annealing. (C) 1999 American Institute of Physics. [S0021-8979(99)51008-6]. C1 Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. NIST, Microanal Res Grp, Gaithersburg, MD 20899 USA. RP Chowdary, KM (reprint author), Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. RI Majetich, Sara/B-1022-2015 OI Majetich, Sara/0000-0003-0848-9317 NR 20 TC 11 Z9 12 U1 1 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4331 EP 4333 DI 10.1063/1.370358 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700017 ER PT J AU Fry, RA Lou, J Reimers, A Bennett, LH Della Torre, E AF Fry, RA Lou, J Reimers, A Bennett, LH Della Torre, E TI Preisach modeling of a magneto-optical medium with perpendicular magnetization SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID CO/PT MULTILAYERS AB Magneto-optical Kerr effect measurements on a (0.3 nm Co/0.6 nm Pt)(15) multilayer film with perpendicular magnetization showed Kerr rotation hysteresis loops that are very square, but asymmetric: on the descending major loop, while the magnetization decreases rapidly once the applied field approaches the coercive field, there is a long tail as saturation is approached. Modeling of this behavior was performed using a Preisach-based approach. To account for the known changes in magnetization behavior as a function of the number of bilayers, the Preisach density function was replaced by the sum of as many Gaussian distributions as there were bilayers in the material. The parameters of these Gaussian functions were systematically varied. The resulting model shows a good fit to both the experimental major loop and a first-order reversal curve. (C) 1999 American Institute of Physics. [S0021-8979(99)23908-4]. C1 George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fry, RA (reprint author), George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. NR 8 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4382 EP 4384 DI 10.1063/1.369791 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700034 ER PT J AU Scott, JHJ Chowdary, K Turgut, Z Majetich, SA McHenry, ME AF Scott, JHJ Chowdary, K Turgut, Z Majetich, SA McHenry, ME TI Neutron powder diffraction of carbon-coated FeCo alloy nanoparticles SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB Neutron powder diffraction is used to study the order-disorder transformation in carbon-coated FexCo1-x nanoparticles produced using a radio frequency plasma torch. The nanoparticles, nominally Fe50Co50, are produced from alloy powder and acetylene precursors by gas-phase nucleation from the plasma. The resulting nanoparticles undergo an order-disorder transformation near 730 degrees C, passing from an ordered B2 (CsCl) structure to a disordered Al (body-centered-cubic) structure upon heating, similar to the transformation seen in bulk equiatomic FeCo. Although it is very difficult to quench the disordered state in bulk samples, the extreme cooling rates present in the plasma reactor produce metastable disordered nanoparticles. Neutron powder diffractograms acquired during a heating-cooling cycle at 27, 500, 710, 800, 710, and 400 degrees C indicate the particles relax to their equilibrium ordered state upon heating first, disorder as they pass through the transformation temperature, and reorder upon cooling. (C) 1999 American Institute of Physics. [S0021-8979(99)37008-0]. C1 Natl Inst Stand & Technol, Microanal Res Grp, Gaithersburg, MD 20899 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Carnegie Mellon Univ, Dept Mat Sci & Engn, Pittsburgh, PA 15213 USA. RP Scott, JHJ (reprint author), Natl Inst Stand & Technol, Microanal Res Grp, Gaithersburg, MD 20899 USA. RI McHenry, Michael/B-8936-2009; Majetich, Sara/B-1022-2015 OI Majetich, Sara/0000-0003-0848-9317 NR 4 TC 26 Z9 28 U1 1 U2 11 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4409 EP 4411 DI 10.1063/1.369800 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700043 ER PT J AU Russek, SE Oti, JO Kaka, S Chen, EY AF Russek, SE Oti, JO Kaka, S Chen, EY TI High-speed characterization of submicrometer giant magnetoresistive devices SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB A microwave test structure has been designed to measure the high-speed response of giant magnetoresistive (GMR) devices. The test structure uses microwave transmission lines for both writing and sensing the devices. Pseudo-spin-valve devices, with line widths between 0.4 and 0.8 mm, were successfully switched with pulses whose full width at half-maximum was 0.5 ns. For small pulse widths tau(pw) the switching fields are observed to increase linearly with 1/tau(pw). The increase in switching fields at short pulse widths is characterized by a slope which, for the current devices, varies between 4 and 16 mu A s/m (50-200 Oe ns). The magnetoresistive response during rotation and switching was observed. For small rotations (similar to 45 degrees between layer magnetizations) the GMR response pulses had widths of 0.46 ns, which is at the bandwidth limit of our electronics. For larger rotations (similar to 90 degrees) the response pulses broadened considerably as the magnetic layers were rotated near the unstable equilibrium point perpendicular to the device axis. Full 180 degrees switches of both soft and hard layers were observed with switching times of approximately 0.5 ns. (C) 1999 American Institute of Physics. [S0021-8979(99)70308-7]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. Motorola Inc, Semicond Technol SPS, Tempe, AZ 85284 USA. RP Russek, SE (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. NR 10 TC 31 Z9 31 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 4773 EP 4775 DI 10.1063/1.370477 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700165 ER PT J AU Arnold, CS Pappas, DP Venus, D AF Arnold, CS Pappas, DP Venus, D TI Domain formation near the reorientation transition in perpendicularly magnetized, ultrathin Fe/Ni bilayer films (invited) SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID ML NI/W(110) FILMS; PHASE-DIAGRAM; SUSCEPTIBILITY MEASUREMENTS; ISING-MODEL; FE FILMS; TEMPERATURE; ANISOTROPY; CO/AU(111); DIRECTION; AG(100) AB Ultrathin films with perpendicular magnetization convert from a single domain state into a multidomain structure as the reorientation phase transition to an in-plane magnetization is approached. Reorientation transitions in magnetic ultrathin films result from the interplay of interfacial magnetic anisotropy, the dipolar interaction, and two-dimensional thermodynamics. These transitions can be driven by changing either the film thickness or temperature. Experimental and theoretical studies of this effect are briefly discussed in the context of the thickness-temperature phase diagram of the reorientation transition. We then describe magnetic susceptibility experiments on ultrathin Fe/Ni(111) bilayers. Our experiments indicate an exponential increase in domain density of a multidomain structure with temperature and identify the region of the thickness-temperature reorientation transition phase diagram where this condensation is most pronounced. The temperature dependence of the domain density agrees quantitatively with theoretical predictions. Films that are slightly too thin to exhibit the reorientation transition with temperature are a special case. They undergo a ferromagnetic-to-paramagnetic transition from the perpendicularly magnetized state and exhibit domain-like behavior many tens of Kelvin above estimates of the Curie temperature. This surprising observation is interpreted using the two-dimensional dipolar Ising model. (C) 1999 American Institute of Physics. [S0021-8979(99)78408-2]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. McMaster Univ, Hamilton, ON, Canada. Brockhouse Inst Mat Res, Hamilton, ON, Canada. RP Arnold, CS (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 31 TC 2 Z9 2 U1 1 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5054 EP 5059 DI 10.1063/1.370089 PN 2A PG 6 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700259 ER PT J AU Sandler, GM Bertram, HN Silva, TJ Crawford, TM AF Sandler, GM Bertram, HN Silva, TJ Crawford, TM TI Determination of the magnetic damping constant in NiFe films SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB A two-dimensional, dynamic, micromagnetic model of a thin strip of permalloy is described and used to model the magnetization dynamics of the strip as it is subjected to a transverse step field. The numerical results are compared to experimental data. The experimental precession frequency is matched by varying H-k, the longitudinal, uniaxial, magnetocrystalline anisotropy field. The damping is matched by varying alpha, the phenomenological damping parameter in the LLG equation. A good fit to the data was obtained with a single damping constant of alpha=0.013. (C) 1999 American Institute of Physics. [S0021-8979(99)65008-3]. C1 Univ Calif San Diego, Ctr Magnet Recording Res, La Jolla, CA 92093 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Sandler, GM (reprint author), Headway Technol Inc, 678 S Hillview Dr, Milpitas, CA 95035 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 8 TC 41 Z9 42 U1 1 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5080 EP 5082 DI 10.1063/1.370096 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700266 ER PT J AU Rice, P Russek, SE AF Rice, P Russek, SE TI Observation of the effects of tip magnetization states on magnetic force microscopy images SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB We have investigated the effect of the orientation between the tip and the tip-magnetizing field on the subsequent magnetic force microscopy images. We have observed that commonly used CoCr coated tips have a component of the remanent magnetization pinned parallel to the tip axis. In order to study the pinned component of the tip, saturating fields were applied at various angles relative to the tip axis. Each time the tip was magnetized, we imaged a hard disk sample that had lithographically patterned landmarks designed to allow us to find, image, and compare images of the same nanometer-sized magnetic feature. We have also observed a component of the tip magnetization that is free to rotate dynamically due to the stray magnetic fields of the sample being imaged. To study this effect, an external bias field was applied parallel to the tip axis while imaging. This field effectively pinned the tip magnetization. With these techniques, we are thus able to compare two effects of tip magnetization on magnetic force microscope images. [S0021-8979(99)42708-2]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Rice, P (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 5 Z9 5 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5163 EP 5165 DI 10.1063/1.369111 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700293 ER PT J AU Fry, RA Bennett, LH Della Torre, E AF Fry, RA Bennett, LH Della Torre, E TI Kerr imaging of a Co/Pt bimodal magneto-optical medium SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID BEAM-EPITAXIAL-GROWTH; MAGNETIZATION REVERSAL; 111 AXES; FILMS AB Spatially resolved magneto-optical (MO) images of a (0.3 nm Co/1.2nm Pt)(15) multilayer film with perpendicular magnetic anisotropy have been obtained by Kerr microscopy. This material exhibits a major hysteresis loop with two-step magnetization reversal. The MO images display four possible "stable" magnetic states distinguished by four different intensities. This behavior is explained by the presence of two different magnetic phases each which has a stable magnetization state either parallel or antiparallel to the applied field, and which may reverse quasi-independently from one another. (C) 1999 American Institute of Physics. [S0021-8979(99)22008-7]. C1 George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fry, RA (reprint author), George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. NR 10 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5169 EP 5171 DI 10.1063/1.369113 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700295 ER PT J AU Harris, VG Fatemi, DJ Hathaway, KB Huang, Q Mohan, A Long, GJ AF Harris, VG Fatemi, DJ Hathaway, KB Huang, Q Mohan, A Long, GJ TI Atomic structure and magnetism of ordered and disordered Al0.5Fe0.5-xMnx alloys SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB The equiatomic FeAl alloy has been modified by partial substitution of Mn for Fe, and its magnetic and structural properties investigated by neutron diffraction (ND), x-ray absorption fine structure (XAFS) spectroscopy, Mossbauer spectroscopy (MS), and SQUID magnetometry both for the ordered (B2) and disordered states. The unit cell volume is measured to increase linearly with Mn concentration. XAFS measurements indicate local structural displacements occur at the Mn sites in both ordered and disordered states that may act to frustrate long-range magnetic order (LRMO). Although MS and ND show no evidence of LRMO, SQUID magnetometry indicates an induced movement in the ordered state that increases with disorder but does not saturate at fields up to 5 T. (C) 1999 American Institute of Physics. [S0021-8979(99)15408-2]. C1 USN, Res Lab, Washington, DC 20375 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Univ Missouri, Dept Chem, Rolla, MO 65409 USA. RP Harris, VG (reprint author), USN, Res Lab, Washington, DC 20375 USA. RI Harris, Vincent/A-8337-2009 NR 10 TC 2 Z9 2 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5181 EP 5183 DI 10.1063/1.369117 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700299 ER PT J AU Russek, SE Crawford, TM Silva, TJ AF Russek, SE Crawford, TM Silva, TJ TI Study of NiFe/Al/Al2O3 magnetic tunnel junction interfaces using second-harmonic magneto-optic Kerr effect SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID MAGNETORESISTANCE AB Using the second-harmonic magneto-optic Kerr effect (SHMOKE), we have measured the interfacial magnetic properties of NiFe/Al/Al2O3 heterostructures as a function of Al2O3 thickness and processing conditions. The samples were prepared like magnetic tunnel junctions except that the top electrodes were not deposited. A large change in SHMOKE contrast was observed for different oxidation processes and Al2O3 thicknesses. The magnetic SHMOKE contrast from a plasma oxidized sample in which the oxidation front is thought to be inside the original NiFe film is 70%, whereas the SHMOKE contrast from a thermally oxidized NiFe/Al sample, in which the oxidation front is similar to 1 nm from the Al/NiFe interface is only 15%. Further, the phase of the signal is reversed between the two structures. The SHMOKE data have been correlated with tunneling measurements on similarly fabricated structures. For the two samples listed above, the junction resistivity varied from 10(-1) Omega cm(2) (plasma oxidized) to 10(-6) Omega cm(2) (thermally oxidized). These results indicate that SHMOKE may be useful for assessing tunnel junction quality during processing. [S0021-8979(99)49408-3]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Russek, SE (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 4 Z9 4 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5273 EP 5275 DI 10.1063/1.369852 PN 2A PG 3 WC Physics, Applied SC Physics GA 188MK UT WOS:000079850700327 ER PT J AU Li, WH Wu, SY Lee, KC Lynn, JW Liu, RS Wu, JB Huang, CY AF Li, WH Wu, SY Lee, KC Lynn, JW Liu, RS Wu, JB Huang, CY TI Magnetic order and spin reorientation in Nd0.45Ca0.55MnO3 SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID NEUTRON-DIFFRACTION; DOUBLE EXCHANGE; MAGNETORESISTANCE; FIELD AB Neutron diffraction and ac magnetic susceptibility measurements have been performed to study the magnetic ordering of the Mn spins in polycrystalline Nd0.45Ca0.55MnO3. Three peaks around 260, 90, and 40 K were observed in the temperature dependence of the ac susceptibility. Structural analysis using high-resolution neutron diffraction patterns shows that the peak at 260 K is associated with the charge ordering of the Mn ions. Neutron magnetic diffraction shows that the peak at 90 K originates from the ordering of the Mn spins. Both ferromagnetic and antiferromagnetic couplings between the Mn spins were found. The spin structure in the basal plane consists of tilted ferromagnetic chains (along the [110] direction) aligned antiferromagnetically, whereas the interlayer coupling is ferromagnetic. A spin reorientation occurs below 15 K, which results in a change in the title angle. The Mn spins order at T-N approximate to 120 K, and the moment saturated at 30 K at [mu(Z)]=2.29(4)mu(B). (C) 1999 American Institute of Physics. [S0021-8979(99)26008-2]. C1 Natl Cent Univ, Dept Phys, Chungli 32054, Taiwan. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Natl Taiwan Univ, Dept Chem, Taipei 106, Taiwan. Natl Taiwan Univ, Ctr Condensed Matter Sci, Taipei 106, Taiwan. RP Li, WH (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 13 TC 4 Z9 4 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5588 EP 5590 DI 10.1063/1.369808 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500102 ER PT J AU McMichael, RD Donahue, MJ Porter, DG Eicke, J AF McMichael, RD Donahue, MJ Porter, DG Eicke, J TI Comparison of magnetostatic field calculation methods on two-dimensional square grids as applied to a micromagnetic standard problem SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc AB Magnetization reversal modes and coercivities were calculated for a magnetic particle with thickness : width : length aspect ratios 0.1 : 1 : 5 as a function of the reduced particle width d/l(ex), where d is the particle width and l(ex) is the intrinsic magnetostatic exchange length. With only exchange energy and magnetostatic energy included, the particle corresponds to mMAG standard problem No. 2. The problem is modeled with two-dimensional grids of three-dimensional spins, and the results are compared for two methods of calculating magnetostatic energies, the "constant magnetization'' method and the "constant charge'' method. For both magnetostatic computational methods, the coercivity decreases from H-c/M-s = 0.06+/-0.003 to 0.014+/-0.003 over the range 3 < d/l(ex)<80, where the uncertainties reflect the field step size. Also over this interval, as d/l(ex) increases, the magnetization exhibits three modes of reversal: nearly uniform rotation, transverse switching of end domains followed by propagation of head-to-head domain walls from the ends to the center of the particle, and nucleation and propagation of vortices accompanied by more complex domain structures. (C) 1999 American Institute of Physics. [S0021-8979(99)65708-5]. 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 6 TC 18 Z9 18 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5816 EP 5818 DI 10.1063/1.369929 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500177 ER PT J AU Borchers, JA Ijiri, Y Lind, DM Ivanov, PG Erwin, RW Lee, SH Majkrzak, CF AF Borchers, JA Ijiri, Y Lind, DM Ivanov, PG Erwin, RW Lee, SH Majkrzak, CF TI Polarized neutron diffraction studies of exchange-coupled Fe3O4/NiO superlattices SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID THIN-FILMS; MAGNETIC-PROPERTIES; NIO; INTERFACES AB In order to understand the interplay between exchange coupling and magnetic structure, we have examined the magnetic ordering of a series of epitaxial Fe3O4/NiO superlattices using polarized neutron diffraction techniques. As expected, the net ferrimagnetic moment of the Fe3O4 layers aligns parallel to an applied magnetic field. The antiferromagnetic NiO spins order into alternating antiparallel [111] planes as in bulk, but the direction of the spins in the planes are determined by field preparation. The NiO moments tend to align perpendicular to the field. In addition, the relative population of the NiO domains varies as the field is raised. The changes in the antiferromagnetic spin order relative to bulk seem to result from magnetic coupling with the Fe3O4 moments. (C) 1999 American Institute of Physics. [S0021-8979(99)67708-8]. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Florida State Univ, Dept Phys, Tallahassee, FL 32306 USA. RP Borchers, JA (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 23 TC 10 Z9 11 U1 0 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 5883 EP 5885 DI 10.1063/1.369902 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500196 ER PT J AU Chopra, HD Ludwig, A Quandt, E Hua, SZ Brown, HJ Swartzendruber, LJ Wuttig, M AF Chopra, HD Ludwig, A Quandt, E Hua, SZ Brown, HJ Swartzendruber, LJ Wuttig, M TI Magnetic mesostructure of giant magnetostrictive spring magnet type multilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 43rd Annual Conference on Magnetism and Magnetic Materials CY NOV 09-12, 1998 CL MIAMI, FLORIDA SP Amer Inst Phys, IEEE Magnet Soc, Minerals Met Mat Soc, Amer Soc Testing & Mat, Amer Ceramic Soc, Amer Phys Soc, EMTEC Magnet GmbH, Fuji Photo Film Co Ltd, IBM, Imation, Sony corp, TDK Corp, Toda Kogyo Corp, ADE Technol Inc, digital Measurement Syst Div, Komag, MMC Technol Inc ID THIN-FILMS AB The magnetic behavior of giant magnetostrictive TbFe/FeCo multilayers show that individual layers of as-deposited multilayers in their demagnetized state are single domain due to stray-field coupling between adjacent layers. Such multilayers do not show a collective behavior during magnetization reversal. In contrast, stress-free films obtained by annealing at 543 K for 1 h subdivide themselves into multiple domains to lower their overall energy, and show a collective magnetization behavior. An interesting observation is the dynamic formation and collapse of magnetoelastically induced domains in TbFe layers in annealed multilayers during reversal. (C) 1999 American Institute of Physics. [S0021-8979(99)43808-3]. C1 SUNY Buffalo, Dept Mech & Aerosp Engn, Thin Films & Nanosynth Lab, Buffalo, NY 14260 USA. SUNY Buffalo, Ctr Adv Photon & Elect Mat, Buffalo, NY 14260 USA. Forschungszentrum Karlsruhe, Inst Mat Forsch, D-76021 Karlsruhe, Germany. Mat Innovat Inc, W Lebanon, NH 03784 USA. NIST, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Chopra, HD (reprint author), SUNY Buffalo, Dept Mech & Aerosp Engn, Thin Films & Nanosynth Lab, Buffalo, NY 14260 USA. RI Ludwig, Alfred/G-1111-2011 OI Ludwig, Alfred/0000-0003-2802-6774 NR 8 TC 5 Z9 5 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 15 PY 1999 VL 85 IS 8 BP 6238 EP 6240 DI 10.1063/1.370232 PN 2B PG 3 WC Physics, Applied SC Physics GA 188NF UT WOS:000079853500313 ER PT J AU Tamassia, F Brown, JM Evenson, KM AF Tamassia, F Brown, JM Evenson, KM TI Fine-structure spectrum of the FO radical, observed by far-infrared laser magnetic resonance SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIPOLE-MOMENT; DIATOMIC-MOLECULES; HIGH-RESOLUTION; SPIN-ORBIT; STATE; SPECTROSCOPY; PARAMETERS; BRO AB The fine-structure transition (2)Pi(1/2)<--(2)Pi(3/2) of the free radical FO has been detected by far-infrared laser magnetic resonance. All the observed transitions are magnetic dipole in character. The spinorbit constant A(0) has been determined experimentally; its value of -196.108 686(50) cm(-1) is consistent with previous estimates. The analysis of a set of 290 transitions leads to the determination of a number of molecular parameters including rotational, centrifugal distortion, spin-orbit, lambda-doubling, magnetic hyperfine, and Zeeman terms. All four magnetic hyperfine structure constants a, b(F), c, d for the F-19 nucleus have been determined and are discussed in terms of the expectation values of the appropriate operators over the electronic wave function. (C) 1999 American Institute of Physics. [S0021-9606(99)01315-X]. C1 Phys & Theoret Chem Lab, Oxford OX1 3QZ, England. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Tamassia, F (reprint author), Phys & Theoret Chem Lab, S Parks Rd, Oxford OX1 3QZ, England. EM jmb@physchem.ox.ac.uk NR 28 TC 8 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD APR 15 PY 1999 VL 110 IS 15 BP 7273 EP 7286 DI 10.1063/1.478630 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 184QZ UT WOS:000079625600021 ER PT J AU Van Woert, ML AF Van Woert, ML TI Wintertime dynamics of the Terra Nova Bay polynya SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-ICE CONCENTRATION; SATELLITE PASSIVE MICROWAVE; ROSS SEA; COASTAL POLYNYAS; LONGWAVE RADIATION; OCEANIC PROCESSES; NIMBUS-7 SMMR; GREASE ICE; ANTARCTICA; MODEL AB Three variants of a one-dimensional coastal polynya model, forced by data from a nearby automatic weather station, are used to examine wintertime ice concentration fluctuations in a coastal polynya at Terra Nova Bay, Antarctica. It has long been believed that the Terra Nova Bay polynya opens in response to strong offshore katabatic wind forcing. This study shows that the sensible and longwave heat fluxes share equally in controlling polynya extent fluctuations, and together, these two terms in the energy budget can explain up to similar to 50% of the observed variance in open water fraction. Moreover, this study shows that the wind speed becomes important to the polynya dynamics through amplification of the longwave flux. Finally, this study suggests that local katabatic winds at Terra Nova Bay combined with regional ice conditions set up by winds blowing across the Ross Ice Shelf control the fluctuations in Terra Nova Bay polynya extent. C1 NOAA, Ctr Sci, NOAA NESDIS Off Res & Applicat E RA3, Camp Springs, MD 20746 USA. RP Van Woert, ML (reprint author), NOAA, Ctr Sci, NOAA NESDIS Off Res & Applicat E RA3, Rm-711,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 78 TC 52 Z9 52 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-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 1999 VL 104 IS C4 BP 7753 EP 7769 DI 10.1029/1999JC900003 PG 17 WC Oceanography SC Oceanography GA 187KA UT WOS:000079784700011 ER PT J AU Enfield, DB Mestas-Nunez, AM Mayer, DA Cid-Serrano, L AF Enfield, DB Mestas-Nunez, AM Mayer, DA Cid-Serrano, L TI How ubiquitous is the dipole relationship in tropical Atlantic sea surface temperatures? SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID NORTHEAST BRAZIL; SST VARIABILITY; PACIFIC-OCEAN; RAINFALL; CIRCULATION; ANOMALIES; MODEL AB Several kinds of analysis are applied to sea surface temperature anomalies (SSTA) (1856-1991) to determine the degree to which SSTA of opposite sign in the tropical North and South Atlantic occur. Antisymmetric ("dipole") configurations of SSTA on basin scales are not ubiquitous in the tropical Atlantic. Unless the data are stratified by both season and frequency, inherent dipole behavior cannot be demonstrated. Upon removing the global El Nino-Southern Oscillation signal in SSTA (which is symmetric between the North and South Atlantic) from the data, the regions north or south of the Intertropical Convergence Zone have qualitatively different temporal variabilities and are poorly correlated. Dipole configurations do occur infrequently (12-15% of the time), but no more so than expected by chance for stochastically independent variables. Nondipole configurations that imply significant meridional SSTA gradients occur much more frequently, nearly half of the time. Cross-spectral analysis of seasonally averaged SSTA indices for the North and South Atlantic show marginally significant coherence with antisymmetric phase in two period bands: 8-12 years for the boreal winter-spring and 2.3 years for the boreal summer-fall. Antisymmetric coherence is optimal for a small subregion west of Angola in the South Atlantic, with respect to SSTA of basin scale in the tropical North Atlantic. Dipole variability, even where optimal, explains only a small fraction of the total variance in tropical Atlantic SSTA (< 7%). C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Concepcion, Dept Stat, Concepcion, Chile. Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA. RP Enfield, DB (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. EM enfield@aoml.noaa.gov RI Mestas-Nunez, Alberto/A-1427-2012; Enfield, David/I-2112-2013 OI Mestas-Nunez, Alberto/0000-0002-3546-3668; Enfield, David/0000-0001-8107-5079 NR 28 TC 143 Z9 145 U1 1 U2 12 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 1999 VL 104 IS C4 BP 7841 EP 7848 DI 10.1029/1998JC900109 PG 8 WC Oceanography SC Oceanography GA 187KA UT WOS:000079784700017 ER PT J AU Hansen, DV Thacker, WC AF Hansen, DV Thacker, WC TI Estimation of salinity profiles in the upper ocean SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID TROPICAL PACIFIC-OCEAN; SEA-SURFACE SALINITY; DATA ASSIMILATION; FRESH-WATER; ATLANTIC; CIRCULATION; PRECIPITATION; TEMPERATURE; VARIABILITY; TRANSPORT AB A new algorithm is presented for estimating salinity profiles in the upper ocean from measurements of temperature profiles and surface salinity. In application to the eastern tropical Pacific the method replicates a large fraction of the variability of salinity in the upper few tens of meters and provides modest to substantial improvement at nearly all levels. Estimated salinity profiles are able to characterize barrier layers, regions formed by a halocline within the thermal mixed layer. The rms error of geopotential height calculations based on estimated salinity profiles is reduced more than 50% by this method relative to methods not using surface salinity. Even without the surface salinity measurement some reduction of error in geopotential heights can be obtained relative to previous methods. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL USA. RP Hansen, DV (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Thacker, Carlisle/I-3813-2013 OI Thacker, Carlisle/0000-0002-9285-8826 NR 41 TC 17 Z9 17 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-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 1999 VL 104 IS C4 BP 7921 EP 7933 DI 10.1029/1999JC900015 PG 13 WC Oceanography SC Oceanography GA 187KA UT WOS:000079784700024 ER PT J AU Frison, TW Abarbanel, HDI Earle, MD Schultz, JR Scherer, WD AF Frison, TW Abarbanel, HDI Earle, MD Schultz, JR Scherer, WD TI Chaos and predictability in ocean water levels SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID TIME-SERIES; LYAPUNOV EXPONENTS; DIMENSION INCREASE; NONLINEAR-ANALYSIS; SYSTEMS; SIGNALS; WAVES AB The classical problem of characterizing and classifying ocean water levels (all fluctuations that are greater than a few minutes duration) is examined using methods derived from studies of nonlinear dynamical systems. The motivation for this study is the difficulty of characterizing coastal water level dynamics and tide zones with existing methods. There is also long-standing evidence that coastal water levels are not a simple linear superposition of astronomical tides and other influences. Thus it can be appropriate to view water levels as a single, nonlinear, dynamical system. We show that it is appropriate to treat water levels as chaotic by virtue of the existence of a positive Lyapunov exponent for the seven data sets studied. The integer embedding space (the number of state space coordinates) needed to reconstruct an attractor for data collected from sensors exposed to the open ocean is five. Four dynamical degrees of freedom appear to be required to describe the observed dynamics in a state space reconstructed solely from the observations themselves. Water levels in a complex estuary (Chesapeake Bay) have a global dimension of six and have five dynamical degrees of freedom. The largest global Lyapunov exponents, a measure of predictability, vary from 0.57 h(-1) for a station relatively well exposed to the ocean (Charleston, South Carolina) to 4.6 h(-1) for a station well inside a complex estuary (Baltimore, Maryland). The larger values are generally associated with stations that are less predictable, which is consistent with the errors of the astronomical estimator currently used by the U.S. government to generate tide predictions. Lower values are associated with water levels where the estimator errors are smaller. These results are consistent with the interpretation of the Lyapunov exponents as a measure of dynamical predictability. The dynamical characteristics, notably the Lyapunov exponents, are shown to be good candidates for characterizing water level variability and classifying tide zones. C1 Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. Neptune Sci Inc, Reston, VA 20190 USA. Randle Inc, Great Falls, VA 22066 USA. Univ Calif San Diego, Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA 92093 USA. Univ Calif San Diego, Inst Nonlinear Sci, La Jolla, CA 92093 USA. NOAA, Off Ocean & Earth Sci, Natl Ocean Serv, Silver Spring, MD USA. RP Frison, TW (reprint author), Randle Inc, POB 1010, Great Falls, VA 22066 USA. NR 49 TC 25 Z9 27 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-OCEANS JI J. Geophys. Res.-Oceans PD APR 15 PY 1999 VL 104 IS C4 BP 7935 EP 7951 DI 10.1029/1998JC900104 PG 17 WC Oceanography SC Oceanography GA 187KA UT WOS:000079784700025 ER PT J AU Driscoll, CP AF Driscoll, CP TI Legislation, regulation, and conservation of wild marine mammals SO JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION LA English DT Article; Proceedings Paper CT AVMA Animal Welfare Forum - Marine Mammals CY NOV 06, 1998 CL CHICAGO, ILLINOIS SP Amer Vet Med Assoc C1 Natl Marine Fisheries Serv, Oxford, MD 21654 USA. RP Driscoll, CP (reprint author), Natl Marine Fisheries Serv, 904 S Morris St, Oxford, MD 21654 USA. NR 1 TC 0 Z9 0 U1 0 U2 2 PU AMER VETERINARY MEDICAL ASSOC PI SCHAUMBURG PA 1931 N MEACHAM RD SUITE 100, SCHAUMBURG, IL 60173-4360 USA SN 0003-1488 J9 J AM VET MED ASSOC JI J. Am. Vet. Med. Assoc. PD APR 15 PY 1999 VL 214 IS 8 BP 1187 EP 1191 PG 5 WC Veterinary Sciences SC Veterinary Sciences GA 184WJ UT WOS:000079636500023 PM 10212680 ER PT J AU Wulfmeyer, V AF Wulfmeyer, V TI Investigation of turbulent processes in the lower troposphere with water vapor DIAL and radar-RASS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID DIFFERENTIAL ABSORPTION LIDAR; CONVECTIVE BOUNDARY-LAYER; ALEXANDRITE RING LASER; BOTTOM-UP DIFFUSION; HEAT-FLUX; SEA-SURFACE; TOP-DOWN; TEMPERATURE; PROFILES; ENTRAINMENT AB High-resolution water vapor and wind measurements in the lower troposphere within the scope of the Baltic Sea Experiment (BALTEX) are presented. The measurements were performed during a held campaign with a new water vapor differential absorption lidar (DIAL) system and a radar-radio acoustic sounding system (radar-RASS). The analysis of a continuous 24-h measurement period shows that the resolution and the accuracy of these instruments are capable of measuring profiles of water vapor and vertical wind fluctuation moments up to the second order to investigate turbulent processes in the convective boundary layer. Besides the high-resolution data obtained with each instrument it is their combination that yields a further: important variable in the boundary layer: the turbulent latent heat Aux measured directly using the eddy correlation method. The results demonstrate that active remote sensing instruments like DIAL and radar-RASS can be routinely applied to provide previously unavailable datasets for detailed investigations of turbulent processes. Thus, the instruments can contribute significantly to one of the major goals of regional continental-scale experiments like BALTEX: the investigation of models and the improvement of their parameterization of small-scale processes. C1 NCAR, Atmospher Technol Div, Remote Sensing Facil, Boulder, CO 80301 USA. NOAA, Environm Technol Lab, Boulder, CO USA. RP Wulfmeyer, V (reprint author), NCAR, Atmospher Technol Div, Remote Sensing Facil, POB 3000, Boulder, CO 80301 USA. NR 51 TC 44 Z9 44 U1 0 U2 3 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 15 PY 1999 VL 56 IS 8 BP 1055 EP 1076 DI 10.1175/1520-0469(1999)056<1055:IOTPIT>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187PB UT WOS:000079794200005 ER PT J AU Wulfmeyer, V AF Wulfmeyer, V TI Investigations of humidity skewness and variance profiles in the convective boundary layer and comparison of the latter with large eddy simulation results SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID DIFFERENTIAL ABSORPTION LIDAR; BOTTOM-UP DIFFUSION; WATER-VAPOR; TOP-DOWN; TRANSPORT ASYMMETRY; HEAT-FLUX; TURBULENCE; STATISTICS; MODEL; ENTRAINMENT AB Differential absorption lidar (DIAL) measurements of humidity variance and skewness profiles are presented. A derailed error analysis demonstrates that measurements throughout the convective boundary layer can be performed with an accuracy that is mainly limited by sampling errors due to turbulent statistics. The water vapor variance profiles are compared with results from a large eddy simulation (LES) model to estimate surface and entrainment latent heat fluxes. A promising agreement with surface latent heat fluxes derived by the bulk formula is achieved, but a strong deviation of the variance profiles from the LES results is found in the entrainment zone. Reasons for these discrepancies are discussed. A new approach for the investigation of top-down variance functions using the measured variance profiles is introduced. It is investigated whether the skewness profiles give further information on the turbulent transport of water vapor. This is accomplished by the analysis of the skewness budget equation and a comparison of the skewness profiles with latent heat flux profiles. The results demonstrate that DIAL measurements provide unique datasets for studies of turbulent transport processes in the lower troposphere, finally allowing for comprehensive intercomparisons with models. C1 Natl Ctr Atmospher Res, Atmospher Technol Div, Remote Sensing Facil, Boulder, CO 80307 USA. NOAA, Environm Technol Lab, Boulder, CO USA. RP Wulfmeyer, V (reprint author), Natl Ctr Atmospher Res, Atmospher Technol Div, Remote Sensing Facil, POB 3000, Boulder, CO 80307 USA. NR 40 TC 37 Z9 37 U1 0 U2 3 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 15 PY 1999 VL 56 IS 8 BP 1077 EP 1087 DI 10.1175/1520-0469(1999)056<1077:IOHSAV>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187PB UT WOS:000079794200006 ER PT J AU McPhaden, MJ AF McPhaden, MJ TI El Nino - The child prodigy of 1997-98 SO NATURE LA English DT Editorial Material ID PACIFIC-OCEAN; CLIMATE; MODEL; CYCLE C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP McPhaden, MJ (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. RI McPhaden, Michael/D-9799-2016 NR 20 TC 73 Z9 76 U1 3 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 15 PY 1999 VL 398 IS 6728 BP 559 EP + DI 10.1038/19193 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 186WX UT WOS:000079754700031 ER PT J AU Feely, RA Wanninkhof, R Takahashi, T Tans, P AF Feely, RA Wanninkhof, R Takahashi, T Tans, P TI Influence of El Nino on the equatorial Pacific contribution to atmospheric CO(2) accumulation SO NATURE LA English DT Article ID PARTIAL-PRESSURE; CARBON-DIOXIDE; OCEAN; PCO(2); EVENT AB The equatorial oceans are the dominant oceanic source of CO(2) to the atmosphere, annually amounting to a net flux of 0.7-1.5 Pg (10(15) g) of carbon, up to 72% of which emanates from the equatorial Pacific Ocean(1-3). Limited observations indicate that the size of the equatorial Pacific source is significantly influenced by El Nino events(4-10), but the effect has not been well quantified. Here we report spring and autumn multiannual measurements of the partial pressure of CO(2) in the surface ocean and atmosphere in the equatorial Pacific region. During the 1991-94 El Nino period, the derived net annual sea-to-air flux of CO(2) was 0.3 Pg C from autumn 1991 to autumn 1.992., 0.6 Pg C in 1993, and 0.7 Pg C in 1994. These annual fluxes are 30-80% of that of 1996, a non-EG Nino year. The total reduction of the regional sea-to-air CO(2) nux during the 1991-94 El Nino period is estimated to account for up to one-third of the atmospheric anomaly (the difference between the annual and long-term-average increases in global atmospheric CO(2) content) observed over the same period. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Feely, RA (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM feely@pmel.noaa.gov NR 30 TC 156 Z9 162 U1 1 U2 17 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 15 PY 1999 VL 398 IS 6728 BP 597 EP 601 DI 10.1038/19273 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 186WX UT WOS:000079754700051 ER PT J AU Wells, ML Vallis, GK Silver, EA AF Wells, ML Vallis, GK Silver, EA TI Tectonic processes in Papua New Guinea and past productivity in the eastern equatorial Pacific Ocean SO NATURE LA English DT Article ID IRON; PHYTOPLANKTON; COLLISION; UPLIFT; GROWTH; BELT AB Phytoplankton growth in the eastern equatorial Pacific Ocean today accounts for about half of the 'new' production-the fraction of primary production fuelled by externally supplied nutrients-in the global ocean. The recent demonstration that an inadequate supply of iron limits primary production in this region(1) supports earlier speculation that, in the past, fluctuations in the atmospheric deposition of iron-bearing dust may have driven large changes in productivity(2). But we argue here that only small (similar to 2 nM) increases in the iron concentration in source waters of the upwelling Equatorial Undercurrent are needed to fuel intense diatom production across the entire eastern equatorial Pacific Ocean. Episodic increases in iron concentrations of this magnitude or larger were probably frequent in the past because a large component of the undercurrent originates in the convergent island-are region of Papua New Guinea, which has experienced intensive volcanic, erosional and seismic activity over the past 16 million years. Cycles of plankton productivity recorded in eastern equatorial Pacific sediments may therefore reflect the influence of tectonic processes in the Papua New Guinea region superimposed on the effects of global climate forcing. C1 Univ Maine, Sch Marine Sci, Orono, ME 04469 USA. Univ Calif Santa Cruz, Inst Marine Sci, Santa Cruz, CA 95064 USA. Princeton Univ, GFDL, Princeton, NJ 08544 USA. RP Wells, ML (reprint author), Univ Maine, Sch Marine Sci, Orono, ME 04469 USA. EM mlwells@maine.edu NR 30 TC 62 Z9 66 U1 0 U2 5 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 15 PY 1999 VL 398 IS 6728 BP 601 EP 604 DI 10.1038/19281 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 186WX UT WOS:000079754700052 ER PT J AU Schade, W Preusser, J Osborn, DL Lee, YY deGouw, J Leone, SR AF Schade, W Preusser, J Osborn, DL Lee, YY deGouw, J Leone, SR TI Spatially resolved femtosecond time correlation measurements on a GaAsP photodiode SO OPTICS COMMUNICATIONS LA English DT Article DE GaAsP; NSOM; autocorrelation; defects ID FIELD SPIN MICROSCOPY; MAGNETIC HETEROSTRUCTURES; LASER-PULSES; PHOTOCONDUCTIVITY; PHOTOCURRENT; RESOLUTION; SEMICONDUCTORS; SPECTROSCOPY; DEVICES AB Femtosecond photoconductive near-field microscopy on a GaAsP diffusion type photodiode is used to investigate the response of the purl semiconductor material and impurity defect sites. At an excitation energy of 780 nm, below the bulk band gap, impurity sites approximate to 1 mu m in diameter are observed. These sites exhibit a linear dependence of photoconductivity on light intensity instead of the usual two-photon dependence. The linear response on the defect sites gives rise to a first-order interferometric autocorrelation, while the typical GaAsP semiconductor material in other regions yields a second-order interferometric autocorrelation, which can be used for determinations of temporal shape, phase, and linear chirp of pulses. The results indicate that high concentrations of impurity sites can limit the application of a GaAsP photodiode as a femtosecond auto- or cross-correlator. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Tech Univ Clausthal, Inst Phys, D-38678 Clausthal Zellerfeld, Germany. Synchrotron Radiat Res Ctr, Hsinchu 30077, Taiwan. Univ Utrecht, Inst Marine & Atmospher Res, NL-3584 CC Utrecht, Netherlands. RP Schade, W (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Osborn, David/A-2627-2009; de Gouw, Joost/A-9675-2008 OI de Gouw, Joost/0000-0002-0385-1826 NR 20 TC 16 Z9 17 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD APR 15 PY 1999 VL 162 IS 4-6 BP 200 EP 204 DI 10.1016/S0030-4018(99)00115-7 PG 5 WC Optics SC Optics GA 195DX UT WOS:000080234800006 ER PT J AU Thier, KF Goze, C Mehring, M Rachdi, F Yildirim, T Fischer, JE AF Thier, KF Goze, C Mehring, M Rachdi, F Yildirim, T Fischer, JE TI Metallic properties of the ternary fullerides ABa(2)C(60) (A = K,Rb,Cs) SO PHYSICAL REVIEW B LA English DT Article ID NUCLEAR-MAGNETIC-RESONANCE; RB-87 NMR; RB3C60; DYNAMICS; RB4C60; K3C60; A3C60 AB Electronic properties and molecular dynamics of mixed alkali-alkaline earth fullerides ABa(2)C(60) (A = K,Rb,Cs) an investigated by NMR and compared to the isostructural alkali fullerides ADC,. Consistent with previous Raman investigations, our results indicate a fivefold charge transfer to the: C-60 , a charge state that is not found in pure alkali fullerides. C-13 NMR experiments reveal a metallic ground state for all compounds with an inhomogeneous charge distribution on the fullerene molecule. The importance of electron-electron correlations is discussed in terms of the Korringa enhancement factor. Correlation effects appear to be somewhat similar to the isostructural superconducting A(3)C(60). Transverse relaxation experiments were performed to probe the reorientational dynamics of the C-60 molecules. No dependence of the activation energy of the reorientational motion on the type of alkali ion is found, [S0163-1829(99)00316-6]. C1 Univ Stuttgart, Inst Phys 2, W-70550 Stuttgart, Germany. Univ Montpellier 2, Dynam Phases Condensees Grp, F-34060 Montpellier, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA. RP Thier, KF (reprint author), Univ Stuttgart, Inst Phys 2, Pfaffenwaldring 57, W-70550 Stuttgart, Germany. RI yildirim, taner/A-1290-2009 NR 15 TC 12 Z9 12 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD APR 15 PY 1999 VL 59 IS 16 BP 10536 EP 10540 DI 10.1103/PhysRevB.59.10536 PG 5 WC Physics, Condensed Matter SC Physics GA 193BE UT WOS:000080114800026 ER PT J AU Kline, SR AF Kline, SR TI Polymerization of rodlike micelles SO LANGMUIR LA English DT Article ID ANGLE NEUTRON-SCATTERING; LIQUID-CRYSTALLINE PHASES; SYSTEMS; POLYMERS; BROMIDE; SURFACTANTS; ALIGNMENT; DYNAMICS; RHEOLOGY AB Anew polymerizable surfactant, cetyltrimethylammonium 4-vinylbenzoate (CTVB), has been prepared and investigated. In aqueous solution, highly entangled rodlike aggregates are formed at millimolar surfactant concentrations. Free-radical polymerization of the surfactant counterions results in nearly complete conversion to a stable nonviscous solution. Small-angle neutron scattering reveals that the micellar diameter of 40 Angstrom is unchanged during the polymerization process and that the final polymerized micelle length (400-1200 Angstrom) is determined by the relative initiator concentration. In addition, the parent rodlike micellar aggregates rearrange into spherical micelles at elevated temperature, whereas the polymerized structures are insensitive to temperature changes or dilution. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP NIST, Ctr Neutron Res, Bldg 235,Room E151, Gaithersburg, MD 20899 USA. NR 43 TC 84 Z9 85 U1 1 U2 21 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD APR 13 PY 1999 VL 15 IS 8 BP 2726 EP 2732 DI 10.1021/la981451o PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 187FF UT WOS:000079775700019 ER PT J AU Xiang, D Hsu, NN Blessing, GV AF Xiang, D Hsu, NN Blessing, GV TI Imaging of acoustic surface wave slowness SO APPLIED PHYSICS LETTERS LA English DT Article ID SOLIDS AB An experimental method has been devised for imaging the acoustic surface wave slowness (inverse of the phase velocity) in anisotropic solids. This technique utilizes a specially designed broadband, line-focus ultrasonic transducer to sense the leaky surface waves as well as leaky pseudosurface waves emanating from a solid immersed in water. By rotating such a transducer about its symmetric axis normal to the solid surface, the orientation-dependent time wave forms can be obtained. These wave forms are readily transformed into a surface wave slowness image with a simple algorithm. (C) 1999 American Institute of Physics. [S0003-6951(99)01615-0]. C1 NIST, Automated Prod Technol Div, Gaithersburg, MD 20899 USA. RP Xiang, D (reprint author), NIST, Automated Prod Technol Div, Gaithersburg, MD 20899 USA. EM dan.xiang@nist.gov NR 9 TC 6 Z9 7 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 12 PY 1999 VL 74 IS 15 BP 2236 EP 2238 DI 10.1063/1.123812 PG 3 WC Physics, Applied SC Physics GA 183YT UT WOS:000079583000045 ER PT J AU Hill, SB Haich, CA Dunning, FB Walters, GK McClelland, JJ Celotta, RJ Craighead, HG AF Hill, SB Haich, CA Dunning, FB Walters, GK McClelland, JJ Celotta, RJ Craighead, HG TI Patterning of hydrogen-passivated Si(100) using Ar(P-3(0,2)) metastable atoms SO APPLIED PHYSICS LETTERS LA English DT Article ID SCANNING TUNNELING MICROSCOPE; SILICON NANOSTRUCTURES; HYDROFLUORIC-ACID; LIGHT FORCES; LITHOGRAPHY; SURFACES; NANOLITHOGRAPHY; DEPOSITION; OXIDATION; SI(111) AB We describe the patterning of silicon by exposing a hydrogen-passivated Si(100) surface to Ar(P-3(0,2)) metastable atoms through a fine Ni grid in the presence of a small background pressure of oxygen. Metastable atom impact leads to the formation of a uniform oxide layer that is sufficiently resistant to chemical etching to allow feature depths greater than or similar to 20 nm to be realized. With optical manipulation of the incident metastable atoms, this technique could provide the basis for massively parallel nanoscale fabrication on silicon without the use of organic resists. (C) 1999 American Institute of Physics. [S0003-6951(99)02113-0]. C1 Rice Univ, Dept Phys, Houston, TX 77251 USA. Rice Univ, Rice Quantum Inst, Houston, TX 77251 USA. Natl Inst Stand & Technol, Elect Phys Grp, Gaithersburg, MD 20899 USA. Cornell Univ, Sch Appl & Engn Phys, Ithaca, NY 14853 USA. RP Hill, SB (reprint author), Rice Univ, Dept Phys, Houston, TX 77251 USA. EM fbd@rice.edu RI McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 NR 34 TC 27 Z9 28 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD APR 12 PY 1999 VL 74 IS 15 BP 2239 EP 2241 DI 10.1063/1.123813 PG 3 WC Physics, Applied SC Physics GA 183YT UT WOS:000079583000046 ER PT J AU Gagne, M Valenti, JA Linsky, JL Tagliaferri, G Covino, S Gudel, M AF Gagne, M Valenti, JA Linsky, JL Tagliaferri, G Covino, S Gudel, M TI The active corona of HD 35850 (F8 V) SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : coronae; stars : individual (HD 35850); stars : late-type; stars : rotation; ultraviolet : stars; X-rays : stars ID MAIN-SEQUENCE STARS; X-RAY-EMISSION; SOLAR CORONA; AB DORADUS; ROTATION; NANOFLARES; FLARES; TIME; TEMPERATURES; ABUNDANCES AB We present Extreme Ultraviolet Explorer (EUVE) spectroscopy and photometry of the nearby F8 V star HD 35850 (HR 1817). The EUVE short-wavelength 75-175 Angstrom and medium-wavelength 160-365 Angstrom spectra reveal 28 emission lines from Fe rx and Fe xv to Fe XXIV. The Fe XXI lambda lambda 102, 129 ratio yields an upper limit for the coronal electron density, log n(e) < 11.6 cm(-3). The EUVE short-wavelength spectrum shows a small but clearly detectable continuum. The 75-150 Angstrom line-to-continuum ratio indicates approximately solar Fe abundances, with 0.8 < Z < 1.6 (90% confidence interval). Upper limits have been derived for a dozen high-emissivity Fe x through Fe XIV lines. The resulting emission measure distribution is characterized by two broad temperature components at log T of 6.8 and 7.4. Over the course of the 1 week observation, large-amplitude, long-duration flares were not seen in the EUVE Deep Survey light curve, although the light curve does show signs of persistent, low-level flaring and possible rotational modulation. The EUVE spectra have been compared with nonsimultaneous ASCA SIS spectra of HD 35850 obtained in 1995. The SPEX DEM analysis of the SIS spectrum indicates the same temperature distribution as the EUVE DEM analysis. However, the SIS spectra suggest subsolar abundances, 0.34 < Z < 0.81. Although some of the discrepancy may be the result of incomplete X-ray line lists, we cannot explain the disagreement between the EUVE line-to-continuum ratio and the ASCA-derived Fe abundance. The X-ray surface flux on HD 35850 is comparable to that of cooler dwarfs of comparable age and rotation like EK Draconis (GO V) and AB Doradus (K1 V). Given its youth (t approximate to 100 Myr), its rapid rotation (v sin i approximate to 50 km s(-1)), and its high X-ray activity (L-x approximate to 1.5 x 10(30) ergs s(-1)), HD 35850 may represent an activity extremum for single, main-sequence F-type stars. The variability and emission measure distribution can be reconstructed using the continuous flaring model of Gudel provided that the flare distribution has a power-law index alpha approximate to 1.8. Similar results obtained for other young solar analogs suggest that continuous flaring is a viable coronal heating mechanism on rapidly rotating, late-type, main-sequence stars. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. Osserv Astron Brera, I-22055 Merate, Italy. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. RP Univ Colorado, JILA, Boulder, CO 80309 USA. RI Gagne, Marc/C-1130-2013; Guedel, Manuel/C-8486-2015; OI Guedel, Manuel/0000-0001-9818-0588; Covino, Stefano/0000-0001-9078-5507; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 43 TC 16 Z9 16 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD APR 10 PY 1999 VL 515 IS 1 BP 423 EP 434 DI 10.1086/307009 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 195AF UT WOS:000080226400035 ER PT J AU Burns, TJ Davis, RW Moore, EF AF Burns, TJ Davis, RW Moore, EF TI A perturbation study of particle dynamics in a plane wake flow SO JOURNAL OF FLUID MECHANICS LA English DT Article ID STREAMWISE BRAID VORTICES; STUART VORTEX FLOW; HEAVY-PARTICLES; MIXING LAYERS; DISPERSION; MOTION AB We analyse the dynamics of small, rigid, dilute spherical particles in the far wake of a bluff body under the assumption that the background flow field is approximated by a periodic array of Stuart vortices that can be considered to be a regularization of the von Karman vortex street. Using geometric singular perturbation theory and numerical methods, we show that when inertia (measured by a dimensionless Stokes number) is not too large, there is a periodic attractor in the phase space of the dynamical system governing the particle motion. We argue that this provides a simple mechanism to explain the unexpected 'focusing' effect that has been observed both numerically and experimentally in the far-wake flow past a bluff body by Tang et al. (1992). Their results show that over a range of Reynolds numbers and intermediate values of the Stokes number, particles injected into the wake of a bluff body concentrate near the edges of the vortex structures downstream, thus tending to 'demix' rather than disperse homogeneously. C1 Natl Inst Stand & Technol, Math & Computat Sci Div, Informat Technol Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Proc Measurements Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Burns, TJ (reprint author), Natl Inst Stand & Technol, Math & Computat Sci Div, Informat Technol Lab, Gaithersburg, MD 20899 USA. NR 43 TC 18 Z9 18 U1 0 U2 2 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD APR 10 PY 1999 VL 384 BP 1 EP 26 DI 10.1017/S002211209900419X PG 26 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 200VK UT WOS:000080560600001 ER PT J AU Carasso, AS AF Carasso, AS TI Logarithmic convexity and the "slow evolution" constraint in ill-posed initial value problems SO SIAM JOURNAL ON MATHEMATICAL ANALYSIS LA English DT Article DE ill-posed problems; analytic continuation; backwards in time continuation; logarithmic convexity; Holder-continuity; parabolic equations; growing diffusion coefficients; non self-adjoint problems; Navier-Stokes equations; holomorphic semigroups; subordinated processes; slow evolution from continuation boundary; SECB constraint AB This paper examines a wide class of ill-posed initial value problems for partial differential equations, and surveys logarithmic convexity results leading to Holder-continuous dependence on data for solutions satisfying prescribed bounds. The discussion includes analytic continuation in the unit disc, time-reversed parabolic equations in L-p spaces, the time-reversed Navier-Stokes equations, as well as a large class of nonlocal evolution equations that can be obtained by randomizing the time variable in abstract Cauchy problems. It is shown that in many cases, the resulting Holder-continuity is too weak to permit useful continuation from imperfect data. However, considerable reduction in the growth of errors occurs, and continuation becomes feasible, for solutions satisfying the slow evolution from the continuation boundary constraint, previously introduced by the author. C1 NIST, Dept Math & Computat Sci, Gaithersburg, MD 20899 USA. RP Carasso, AS (reprint author), NIST, Dept Math & Computat Sci, Gaithersburg, MD 20899 USA. NR 29 TC 17 Z9 17 U1 0 U2 0 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 0036-1410 J9 SIAM J MATH ANAL JI SIAM J. Math. Anal. PD APR 9 PY 1999 VL 30 IS 3 BP 479 EP 496 DI 10.1137/S0036141098332366 PG 18 WC Mathematics, Applied SC Mathematics GA 188NG UT WOS:000079853900002 ER PT J AU Pursch, M Sander, LC Egelhaaf, HJ Raitza, M Wise, SA Oelkrug, D Albert, K AF Pursch, M Sander, LC Egelhaaf, HJ Raitza, M Wise, SA Oelkrug, D Albert, K TI Architecture and dynamics of C-22 bonded interphases SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID PHASE LIQUID-CHROMATOGRAPHY; SOLID-STATE NMR; SELF-ASSEMBLED MONOLAYERS; POLYCYCLIC AROMATIC-HYDROCARBONS; NUCLEAR MAGNETIC-RESONANCE; MODIFIED SILICA SURFACES; INTERNAL-REFLECTION FLUORESCENCE; ANISOTROPIC STATIONARY PHASES; MIXED TRIFUNCTIONAL SILANES; BLOCK-LIKE SOLUTES AB The relationship between alkyl phase structure and chromatographic performance is investigated for a series of docosyl (C-22)-modified silica surfaces. The results of solid-state nuclear magnetic resonance (NMR) spectroscopy and fluorescence spectroscopy are evaluated and correlated with liquid chromatographic retention for relevant shape-selective separations. A set of four different stationary phases was prepared by solution and surface polymerization approaches, yielding materials with surface coverages ranging from 3.6 to 7.0 mu mol/m(2). C-13 cross polarization magic angle spinning (CP/MAS) NMR spectra indicate that a predominance of trans conformations exists for high-coverage C-22 phases (>4.0 mu mol/m(2)). Two-dimensional solid-state NMR spectroscopy (wide line separation, WISE) was utilized to evaluate the mobility of the trans and gauche alkyl chain conformations. Temperature-dependent C-13 CP/MAS NMR measurements of the bonded phases exhibit large differences in the dynamic behavior of the immobilized C-22 chains. Unusually high chain rigidity was found for the self-assembled monolayer C-22 phase (7.0 mu mol/m(2)). Fluorescence lifetime measurements of 1,6-diphenylhexatriene (DPH) exhibit two different lifetimes of tau(F) approximate to I and 7 ns, which are ascribed to probe molecule populations in the mobile and bonded phases, respectively. Quantitative evaluation of the fluorescence decay curves shows that the partitioning of DPH into the alkyl phase is favored at higher surface coverages, reaching a maximum at a ligand density of 4.9 mu mol/m(2). Time-resolved fluorescence anisotropy measurements also revealed that probe mobility was minimized at this surface coverage. With increasing temperature, the mobility of DPH was found to increase and the fraction of sorbed molecules to decrease. A shape selectivity test mixture containing five polycyclic aromatic hydrocarbons including DPH was employed for temperature-dependent chromatographic studies. In accord with the spectroscopic results, shape selectivity is enhanced at low temperatures and at high surface coverages. The combination of these spectroscopic and chromatographic tools provides a wealth of information on the surface morphology of systematically prepared C-22 sorbents and greater insight on the molecular recognition process in liquid chromatography. C1 Univ Tubingen, Inst Organ Chem, D-72076 Tubingen, Germany. Univ Tubingen, Inst Theoret & Phys Chem, D-72076 Tubingen, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Albert, K (reprint author), Univ Tubingen, Inst Organ Chem, Morgenstelle 18, D-72076 Tubingen, Germany. NR 88 TC 56 Z9 56 U1 1 U2 9 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 APR 7 PY 1999 VL 121 IS 13 BP 3201 EP 3213 DI 10.1021/ja983046p PG 13 WC Chemistry, Multidisciplinary SC Chemistry GA 187WH UT WOS:000079810800030 ER PT J AU Gaigalas, AK Ruzgas, T AF Gaigalas, AK Ruzgas, T TI The role of the potential distribution at the electrode interface in determining the electron transfer rate constant SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE electroreflectance; electrochemical impedance; electron transfer; interface potential; cytochrome c ID SINGLE-CRYSTAL ELECTRODES; ANION ADSORPTION; SPECTROSCOPY; CAPACITANCE; IMPEDANCE AB Simultaneous electrochemical impedance (EI) and electroreflectance (ER) measurements were performed on 'bare' gold, N-acetyl-L-cysteine(NAC) modified gold, and cytochrome c (cyt c) adsorbed on a NAC modified gold electrode. The electrical impedance of the electrode interface was modeled by a series connection of a constant phase element (CPE), a capacitor, and a resistor. The analysis of the combined EI and ER data yielded the heterogeneous electron transfer (ET) rate constant at each frequency of the modulating potential. This is in contrast to previous techniques which used the frequency dependence of the EI or ER response to obtain a value of the rate constant. Assuming that the Faradaic potential was equal to the potential at the nodes of the three element impedance model yielded frequency dependent rate constants. A small modification of the three element impedance model was needed to obtain a frequency independent rate constant of 850 +/- 80 s(-1). This suggests that the distribution of the potential at the electrode interface (reflected in the choice of the electrical impedance model) is an important factor in the determination of the ET rate constant. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Gaigalas, AK (reprint author), NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RI Ruzgas, Tautgirdas/C-4646-2008 NR 13 TC 17 Z9 17 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD APR 6 PY 1999 VL 465 IS 1 BP 96 EP 101 DI 10.1016/S0022-0728(99)00064-9 PG 6 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 184WL UT WOS:000079636700010 ER PT J AU Nisato, G Ermi, BD Douglas, JF Karim, A AF Nisato, G Ermi, BD Douglas, JF Karim, A TI Excitation of surface deformation modes of a phase-separating polymer blend on a patterned substrate SO MACROMOLECULES LA English DT Article ID DIRECTED SPINODAL DECOMPOSITION; FILMS; MEMBRANES; ADSORPTION; MONOLAYERS; CURVATURE; BILAYERS; MIXTURE; SHAPES AB The phase separation kinetics of ultrathin deuterated poly(styrene)/poly(butadiene) polymer blend films spun cast onto striped self-assembled monolayer (SAM) substrates is studied by atomic force microscopy (AFM). Fourier transform analysis of the AFM topographic data at various stages of the film pattern development reveals the presence of quantized surface deformation modes. These modes are excited by the phase separation process when the scale of phase separation becomes commensurate with the period of the striped surface pattern. Thus, higher frequency modes become excited at early stages of phase separation, and these excitations decay with time as the phase separation pattern further coarsens. The film ultimately self-organizes into a periodic structure in which the fundamental mode has the largest amplitude. The influence of film thickness on the film morphology in this late stage is also investigated. A decrease in the film thickness leads to surface patterns that match those of the SAM substrates with increasing resolution. However, these film patterns break up into droplet arrays along the SAM stripes if the films are made too thin. This phenomenon is attributed to a capillary wave instability. C1 Natl Inst Stand & Technol, Div Polymer, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Div Polymer, Gaithersburg, MD 20899 USA. NR 49 TC 85 Z9 85 U1 0 U2 13 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 6 PY 1999 VL 32 IS 7 BP 2356 EP 2364 DI 10.1021/ma981546x PG 9 WC Polymer Science SC Polymer Science GA 184XD UT WOS:000079638300036 ER PT J AU Luo, R Head, MS Given, JA Gilson, MK AF Luo, R Head, MS Given, JA Gilson, MK TI Nucleic acid base-pairing and N-methylacetamide self-association in chloroform: affinity and conformation SO BIOPHYSICAL CHEMISTRY LA English DT Article; Proceedings Paper CT CECAM Workshop on Implicit Solvent Models for Biomolecular Simulations CY MAY, 1998 CL CTR CALCUL ATOM & MOLEC, LYON, FRANCE SP Ctr Calcul Atom & Molec HO CTR CALCUL ATOM & MOLEC ID MONTE-CARLO SIMULATIONS; HYDROGEN-BOND FORMATION; FREE-ENERGIES; ENANTIOSELECTIVE BINDING; AQUEOUS-SOLUTIONS; SOLVENT MODELS; SOLVATION; MOLECULES; DYNAMICS; ELECTROSTATICS AB A recently developed computational method, 'mining minima', is used to examine the hydrogen-bonding interactions of nucleic acid base-pairs and of the N-methylacetamide homodimer in chloroform. The mining minima algorithm aggressively samples molecular conformations, identifies the most important local minima, and computes their contributions to the overall free energy of the system. Here, the CHARMM 98 parameter set is used for the potential energy and the generalized Born/surface area solvent model is used to account for the influence of the solvent. Good agreement with experiment is obtained for the non-covalent binding affinities of a series of complexes. The computational approach used here is applicable to a range of molecular systems. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gilson, MK (reprint author), Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. RI Luo, Ray/I-6928-2012 OI Luo, Ray/0000-0002-6346-8271 FU NIGMS NIH HHS [GM54053] NR 46 TC 28 Z9 28 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-4622 J9 BIOPHYS CHEM JI Biophys. Chem. PD APR 5 PY 1999 VL 78 IS 1-2 BP 183 EP 193 DI 10.1016/S0301-4622(98)00229-4 PG 11 WC Biochemistry & Molecular Biology; Biophysics; Chemistry, Physical SC Biochemistry & Molecular Biology; Biophysics; Chemistry GA 191UZ UT WOS:000080041100013 PM 10343387 ER PT J AU Ortigoso, J Fraser, GT Pate, BH AF Ortigoso, J Fraser, GT Pate, BH TI Pendular states of highly vibrationally excited molecules SO PHYSICAL REVIEW LETTERS LA English DT Article ID ARTIFICIAL-INTELLIGENCE METHODS; INTRAMOLECULAR DYNAMICS; ELECTRIC-FIELD; ALIGNMENT; MONOFLUOROACETYLENE; SPECTROSCOPY; RELAXATION; SPECTRA; LASER AB The behavior of coherent field-induced hybrids of held-free rotor states ("pendular states") is studied in energy regions where intramolecular vibrational energy redistribution phenomena are important. The energy region corresponding to the 4v(1) band system of HCCF molecules, at approximately 12 800 cm(-1) has been chosen as an example. The calculations show that the expectation value of the orientation of molecules prepared in nonstationary: pendular bright states exhibits a slow decay to the equilibrium value. Therefore the molecules substantially conserve their initial orientation after intramolecular vibrational redistribution takes place. [S0031-9007(99)08810-9]. C1 CSIC, Inst Estruct Mat, Madrid 28006, Spain. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. RP Ortigoso, J (reprint author), CSIC, Inst Estruct Mat, Serrano 121, Madrid 28006, Spain. RI Ortigoso, Juan/F-1234-2016 NR 17 TC 9 Z9 9 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 5 PY 1999 VL 82 IS 14 BP 2856 EP 2859 DI 10.1103/PhysRevLett.82.2856 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800012 ER PT J AU Jach, T Zhang, Y Colella, R de Boissieu, M Boudard, M Goldman, AI Lograsso, TA Delaney, DW Kycia, S AF Jach, T Zhang, Y Colella, R de Boissieu, M Boudard, M Goldman, AI Lograsso, TA Delaney, DW Kycia, S TI Dynamical diffraction and x-ray standing waves from atomic planes normal to a twofold symmetry axis of the quasicrystal AlPdMn SO PHYSICAL REVIEW LETTERS LA English DT Article ID AL-PD-MN; SURFACE-STRUCTURE DETERMINATION; QUASI-CRYSTALS; ICOSAHEDRAL PHASE; ALLOYS; ORDER AB We have observed dynamical diffraction in the [0240 (2) over bar 4] and [0460 (4) over bar 6] reflections of the icosahedral quasicrystal AlPdMn in the back-reflection geometry (theta(B) = 90 degrees). The x-ray fluorescence From the A1 and Pd atoms exhibits strong standing wave behavior, similar to that observed in crystalline materials. The data indicate a long-range order of each species of atoms, with the coherent positions attributable to distributions of the Al and Pd, which we compare to a centrosymmetric model. We observe deviations from the model which imply small departures from inversion symmetry along the twofold symmetry axis and from the expected coherent fractions for Al. [S0031-9007(99)08910-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. ENSEEG, LTPCM, F-38402 St Martin Dheres, France. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. Cornell Univ, CHESS, Ithaca, NY 14853 USA. RP Jach, T (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 24 TC 18 Z9 18 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD APR 5 PY 1999 VL 82 IS 14 BP 2904 EP 2907 DI 10.1103/PhysRevLett.82.2904 PG 4 WC Physics, Multidisciplinary SC Physics GA 182GL UT WOS:000079490800024 ER PT J AU Peiser, HS De Bievre, P AF Peiser, HS De Bievre, P TI Traceability in measurement - time for an update? SO ACCREDITATION AND QUALITY ASSURANCE LA English DT Editorial Material DE traceability; metrology in chemistry; vocabulary in metrology C1 Commiss European Communities, JRC, IRMM, B-2460 Kasterlee, Belgium. NIST, Gaithersburg, MD 20877 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-1775 J9 ACCREDIT QUAL ASSUR JI Accredit. Qual. Assur. PD APR PY 1999 VL 4 IS 4 BP 154 EP 155 DI 10.1007/s007690050337 PG 2 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA 192RV UT WOS:000080093600008 ER PT J AU Fornasiero, F Lue, L Bertucco, A AF Fornasiero, F Lue, L Bertucco, A TI Improving cubic EOSs near the critical point by a phase-space cell approximation SO AICHE JOURNAL LA English DT Article ID RENORMALIZATION-GROUP; VAPOR-PRESSURES; CRITICAL REGION; SIMPLE FLUIDS; STATE; MODEL AB Cubic equations of state (EOSs) are widely used to model the thermodynamic properties of pure fluids and mixtures. However, because they fail to account for the long-range fluctuations existing in a fluid near the critical point, they do not accurately predict the fluid properties in the critical region. Recently, an approximate renormalization group method was developed that can account for these fluctuations. A similar method is applied to provide corrections to a generalized cubic EOS for pure fluids, which is able to represent all classic cubic EOSs. The proposed approach requires two additional parameters: <(c)over bar(RG)> and Delta. The value of <(c)over bar(RG)> is correlated to experimental critical compressibility data, while Delta is set equal to 1. The method is applied to predict the saturated liquid density of fluids of different polarity, and the corrections to the original EOS are found to significantly improve the predictions of this property both far from and close to the critical point. Finally, a correlation is presented for the direct evaluation of the parameter <(c)over bar(RG)> from the value of the critical compressibility factor. C1 Univ Padua, Ist Impianti Chim, I-35131 Padua, Italy. RP Lue, L (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway,838-08, Boulder, CO 80303 USA. RI Lue, Leo/E-7846-2011; Fornasiero, Francesco/I-3802-2012 OI Lue, Leo/0000-0002-4826-5337; NR 22 TC 11 Z9 11 U1 0 U2 1 PU AMER INST CHEMICAL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0001-1541 J9 AICHE J JI AICHE J. PD APR PY 1999 VL 45 IS 4 BP 906 EP 915 DI 10.1002/aic.690450421 PG 10 WC Engineering, Chemical SC Engineering GA 185TL UT WOS:000079686400020 ER PT J AU Terrados, J Borum, J Duarte, CM Fortes, MD Kamp-Nielsen, L Agawin, NSR Kenworthy, WJ AF Terrados, J Borum, J Duarte, CM Fortes, MD Kamp-Nielsen, L Agawin, NSR Kenworthy, WJ TI Nutrient and mass allocation of South-east Asian seagrasses SO AQUATIC BOTANY LA English DT Article DE ramet size; mass allocation; nutrient allocation; seagrasses; South-east Asia ID CYMODOCEA-NODOSA; TERRIGENOUS SEDIMENTS; EXPERIMENTAL BURIAL; COMMUNITY STRUCTURE; GROWTH; MEADOW; PRODUCTIVITY; PHOSPHORUS; INDONESIA; DYNAMICS AB Differences in ramet size (i.e, the mass of a shoot with its share of leaves, rhizome and roots) and allocation of mass and nutrients to different ramet components were quantified based on a comparative analysis of these properties in a large set of seagrass meadows under contrasting conditions of nutrient availability in the Philippines and Thailand. The ramet size differed by two orders of magnitude between the smallest species, Halophila ovalis (12 mg DW per ramet), and the largest, Enhalus acoroides (7.3 g DW per ramet). However, the pattern of mass allocation to different ramet components was similar among species. The vertical rhizome was the most variable ramet component, Compared to seagrasses in general, nitrogen concentrations in the leaves of these South-east Asian seagrasses were low (leaf N less than or equal to 2% DW), and the phosphorus concentrations high (leaf P > 0.2% DW). The amount of nutrients allocated to leaves was of the same magnitude as that to rhizomes and roots. Seagrass ramet mass and the percentage of mass allocated to roots were independent of total nitrogen or phosphorus in the sediment far most species. The nutrient concentrations of seagrass tissues differed among coexisting species which suggests that differences in the nutritional status among South-east Asian species are more dependent on species-specific differences in nutrient acquisition or requirements than on nutrient availability in the sediment. (C) 1999 Elsevier Science B.V, All rights reserved. C1 CSIC, Ctr Estudios Avanzados Blanes, Blanes 17300, Girona, Spain. Univ Copenhagen, Freshwater Biol Lab, DK-3400 Hillerod, Denmark. Univ Philippines, Coll Sci, Inst Marine Sci, Quezon 1101, Philippines. NOAA, Natl Marine Fisheries Serv, SE Fisheries Ctr, Beaufort Lab, Beaufort, NC 28516 USA. RP Terrados, J (reprint author), CSIC, Ctr Estudios Avanzados Blanes, Cami Santa Barbara S-N, Blanes 17300, Girona, Spain. RI Terrados, Jorge/B-1062-2008; Duarte, Carlos M/A-7670-2013; Borum, Jens/K-5167-2014; Agawin, Nona Sheila/I-3168-2015 OI Terrados, Jorge/0000-0002-0921-721X; Duarte, Carlos M/0000-0002-1213-1361; Borum, Jens/0000-0002-4861-6563; Agawin, Nona Sheila/0000-0001-5951-360X NR 32 TC 17 Z9 20 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3770 J9 AQUAT BOT JI Aquat. Bot. PD APR PY 1999 VL 63 IS 3-4 BP 203 EP 217 DI 10.1016/S0304-3770(99)00004-2 PG 15 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 185HV UT WOS:000079663700003 ER PT J AU Fisher, SW Chordas, SW Landrum, PF AF Fisher, SW Chordas, SW Landrum, PF TI Lethal and sublethal body residues for PCB intoxication in the oligochaete, Lumbriculus variegatus SO AQUATIC TOXICOLOGY LA English DT Article DE critical body residues; Lumbriculus variegatus; PCBs; narcosis; sublethal endpoints ID FRESH-WATER AMPHIPODS; SEDIMENT-ASSOCIATED PYRENE; GENERAL-ANESTHESIA; TOXICITY; TOXICOKINETICS; BIOACCUMULATION; INVERTEBRATES; ACCUMULATION; FLUORANTHENE; CHEMICALS AB The oligochaete, Lumbriculus variegatus, was used to examine the utility of critical body residues in describing lethal and sublethal chronic endpoints during polychlorinated biphenyls (PCB) exposure. L. variegatus was exposed to four C-14-PCB congeners and 2,2-bis-(p-chlorophenyl)-1,1-dichloroethylene (DDE) on algal cells. Accumulation and resulting effects were monitored in 10-day acute and 35-day chronic exposures. L. variegatus was resistant to the acute lethal narcotic effects of these contaminants and no mortality was obtained in 10-day exposures. However, mortality that was significantly different from unexposed controls occurred for four compounds in 35-day assays; average body residues for chronic mortality were consistent among contaminants (0.88-1.35 mmol kg(-1)). Kinetic studies showed that failure to generate mortality in some exposures was due to rapid elimination. Mono-2-chlorobiphenyl, for instance, had a K-d of 0.22 h(-1) which was seven to 44 times faster than for the other contaminants. Sublethal reductions in body mass and reproduction occurred at lower body residues than were needed to produce mortality (0.34-0.56 mmol kg(-1)). The consistency of the sublethal data suggests that they may offer a means of interpreting residue data for PCBs in the environment. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ohio State Univ, Environm Sci Program, Columbus, OH 43210 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Fisher, SW (reprint author), Ohio State Univ, Environm Sci Program, 1735 Neil Ave, Columbus, OH 43210 USA. EM fisher.14@postbox.acs.ohio-state.edu NR 44 TC 39 Z9 41 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD APR PY 1999 VL 45 IS 2-3 BP 115 EP 126 DI 10.1016/S0166-445X(98)00103-9 PG 12 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA 176AR UT WOS:000079128800004 ER PT J AU Krone, CA Stein, JE AF Krone, CA Stein, JE TI Species dependent biotransformation and tissue distribution of tributyltin in two marine teleosts SO AQUATIC TOXICOLOGY LA English DT Article DE tributyltin; TBT; biotransformation; metabolism; marine flatfish ID NORMAL-BUTYLTINDICHLORIDE DBTC; POECILIA-RETICULATA GUPPY; RED-SEA BREAM; ORGANOTIN COMPOUNDS; BIS(TRI-NORMAL-BUTYLTIN)OXIDE TBTO; TRIPHENYLTIN CHLORIDE; TEMPORAL DISTRIBUTION; ANTIFOULING PAINTS; ACUTE TOXICITY; RAINBOW-TROUT AB Two marine flatfish species, English sole (Pleuronectes vetulus) and starry flounder (Platichthys stellatus), were exposed intermuscularly to tributyltin chloride (TBT) at 0.93 mg tin/kg body weight. The tissue concentrations of TBT and its biotransformation products dibutyltin (DBT) and monobutyltin (MBT) were monitored over a three week period. Tributyltin concentrations generally reached a maximum in all tissues by 24 h post exposure. At 24 h, the bile contained the greatest concentrations of tin, followed by the liver and kidney, and then by spleen and muscle. Total butyltins were generally present at higher concentrations in starry flounder than in English sole for all tissues, except gall bladder, at all time points. In both species the concentration of hepatic DBT increased with time. The time-point at which TBT and DBT concentrations became approximately equal was between 1 and 3 days for English sole and between 7 and 14 days for starry flounder. The ratios of hepatic TBT to DBT concentrations at all time-points from 1 to 21 days were significantly lower in English sole compared to starry flounder, suggesting more rapid biotransformation of TBT in English sole. First-order elimination rate constants for TBT in liver were 0.061 and 0.068 day(-1) for English sole and starry flounder, respectively. The kidney TBT half-lives were shorter in flatfish than in rainbow trout. Published by Elsevier Science B.V. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Krone, CA (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. EM CAKrone@aol.com NR 37 TC 15 Z9 17 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD APR PY 1999 VL 45 IS 2-3 BP 209 EP 222 DI 10.1016/S0166-445X(98)00093-9 PG 14 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA 176AR UT WOS:000079128800011 ER PT J AU Matsuya, Y Matsuya, S Antonucci, JM Takagi, S Chow, LC Akamine, A AF Matsuya, Y Matsuya, S Antonucci, JM Takagi, S Chow, LC Akamine, A TI Effect of powder grinding on hydroxyapatite formation in a polymeric calcium phosphate cement prepared from tetracalcium phosphate and poly(methyl vinyl ether maleic acid) SO BIOMATERIALS LA English DT Article DE tetracalcium phosphate; apatite; powder grinding; polymeric acid cement AB The primary aim of this study was to determine if cements based on poly(methyl vinyl ether-maleic acid) (PMVE-Ma) and tetracalcium phosphate resulted in hydroxyapatite formation. In addition, the mechanical strength of this type of polymeric calcium phosphate cement was evaluated. Cements were prepared by mixing, in a powder/liquid mass ratio of 3.0, an aqueous solution of PMVE-Ma (mass fraction = 25%) and tetracalcium phosphate powders ground for Various periods of time. The tetracalcium phosphate powders and set cements were characterized by means of X-ray powder diffraction and scanning electron microscopy. Mechanical strengths of the cements were tested 24 h after mixing. Prolonged grinding of tetracalcium phosphate powder decreased particle size and/or crystallite size and increased lattice distortion. This enhanced the reactivity of the tetracalcium phosphate powder and elevated the extent of crosslinking between PMVE-Ma molecules, resulting in improved mechanical strength. Hydroxyapatite formation was detected in the cement prepared with the most finely ground tetracalcium phosphate powder. The conversion of residual tetracalcium phosphate particles to more thermodynamically stable hydroxyapatite crystals will reduce the solubility of the polymeric cement and increase its biocompatibility. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Kyushu Univ, Dept Operat Dent & Endodontol, Fac Dent, Higashi Ku, Fukuoka 812, Japan. Kyushu Univ, Dept Dent Mat Engn, Fac Dent, Higashi Ku, Fukuoka 812, Japan. Natl Inst Stand & Technol, Dent & Med Mat Grp, Div Polymers, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Matsuya, Y (reprint author), Kyushu Univ, Dept Operat Dent & Endodontol, Fac Dent, Higashi Ku, 3-1-1 Maidashi, Fukuoka 812, Japan. FU NIDCR NIH HHS [DE11789] NR 15 TC 25 Z9 27 U1 0 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-9612 J9 BIOMATERIALS JI Biomaterials PD APR PY 1999 VL 20 IS 7 BP 691 EP 697 DI 10.1016/S0142-9612(98)00231-2 PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 176XR UT WOS:000079177900011 PM 10208412 ER PT J AU Cole, KD AF Cole, KD TI Reversible gels for electrophoresis and isolation of DNA SO BIOTECHNIQUES LA English DT Article ID MONOVALENT CATION SALTS; COMMERCIAL GELLAN; PURIFICATION; AGAROSE; GUM AB Here, the application of the gel-forming carbohydrate polymer; gellan gum, for the electrophoresis and isolation of DNA is detailed Gellan gum forms gels in the presence of divalent metal cations, and the gels can be converted back to a solution by the addition of a chelating agent such as EDTA. Also, gellan electrophoresis gels can be formed using diamines. These gels are reversible by increasing the pH, which results in the deprotonation of the diamine. Gellan electrophoresis gels were used for separations at concentrations as low as 0.03%. Native gellan electrophoresis gels have significant electroosmosis and were generally run ovenight. A gellan electrophoresis gel (0.1%) showed good resolution of DNA from approximately 50-1 kbp. The addition of linear polymers, such as hydroxethyl cellulose, to the gellan gum before casting greatly reduced the electroosmosis. The additional polymer increased the resolution of low-molecular-weight DNA down to approximately -200 bp and allowed gels to be run in a few hours. DNA isolated from gellan electrophoresis gels could be cut by common restriction enzymes and ligated in the presence of the gellan gum. The presence of gellan gum did not significantly inhibit the transformation of competent E. coli cells by plasmid DNA. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Cole, KD (reprint author), Natl Inst Stand & Technol, Bldg 222,Room A353, Gaithersburg, MD 20899 USA. NR 15 TC 7 Z9 7 U1 0 U2 5 PU EATON PUBLISHING CO PI NATICK PA 154 E. CENTRAL ST, NATICK, MA 01760 USA SN 0736-6205 J9 BIOTECHNIQUES JI Biotechniques PD APR PY 1999 VL 26 IS 4 BP 748 EP + PG 7 WC Biochemical Research Methods; Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 185UL UT WOS:000079689200027 PM 10343914 ER PT J AU Hard, JJ Hoard, WR AF Hard, JJ Hoard, WR TI Analysis of straying variation in Alaskan hatchery chinook salmon (Oncorhynchus tshawytscha) following transplantation SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID PACIFIC SALMON; COHO SALMON; COLUMBIA RIVER; KISUTCH; PATTERNS; POPULATIONS; BEHAVIOR; STOCKS AB In 1976 chinook salmon (Oncorhynchus tshawytscha) gametes from the Chickamin and Unuk rivers in southeastern Alaska were transplanted 250 km to establish hatchery runs at Little Port Waiter (LPW), Baranof Island. From 1977 to 1989, 1 862 058 marked smelts from 12 broods were released from LPW. Woming and straying were estimated from adult recoveries at 25 locations in Alaska and British Columbia between 1981 and 1989. Of 22 198 LPW fish recovered over this period, 21 934 (98.8%) were collected at LPW. Of 264 fish recovered elsewhere, 38.3% were within 7 km of LPW; 64.4% were within 25 km of LPW. No LPW fish were recovered from the ancestral rivers, but nine fish were recovered from rivers supporting wild chinook salmon. Straying declined with distance from the release site but varied between hatcheries and streams. Straying declined with increasing age and run size. Straying was similar between the populations but varied among broods, and analysis of straying in experimental groups provided evidence for a heritable component. Males strayed more often than females. Population, gender, run size, and recovery age interacted to produce substantial variation in straying, indicating that run composition can produce complex straying responses. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Hard, JJ (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. EM jeff.hard@noaa.gov RI Hard, Jeffrey/C-7229-2009 NR 39 TC 42 Z9 44 U1 1 U2 7 PU CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS PI OTTAWA PA 65 AURIGA DR, SUITE 203, OTTAWA, ON K2E 7W6, CANADA SN 0706-652X EI 1205-7533 J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD APR PY 1999 VL 56 IS 4 BP 578 EP 589 DI 10.1139/cjfas-56-4-578 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 209BR UT WOS:000081027900006 ER PT J AU Bentz, DP Haecker, CJ AF Bentz, DP Haecker, CJ TI An argument for using coarse cements in high-performance concretes SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE high-performance concrete; hydration; microstructure; modeling; particle size distribution ID PORTLAND-CEMENT; HYDRATION; MODEL AB The NIST cement hydration microstructural model and experimental studies are used to investigate the effects of particle size distribution and water-to-cement ratio on hydration kinetics. Cement hydration is limited by the availability of water at the cement particle surfaces. Because a reaction layer forms around each cement particle during hydration, this availability is controlled by two factors: the overall water-to-cement ratio and the particle size distribution of the cement. As the water to-cement ratio is decreased, the effects of particle size distribution on ultimate degree of hydration become less significant. Thus, in the new generation, high-performance concretes, more coarsely ground cements may provide good performance, resulting in substantial energy savings due to a reduction in grinding time. This implies that cement fineness should be optimized based on the mixture proportions of the concrete in which it will be used. Published by Elsevier Science Ltd. All rights reserved. C1 NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Wilhelm Dyckerhoff Inst, Wiesbaden, Germany. RP Bentz, DP (reprint author), NIST, Bldg & Fire Res Lab, Bldg 226,Room B-350, Gaithersburg, MD 20899 USA. NR 12 TC 43 Z9 46 U1 1 U2 4 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 1999 VL 29 IS 4 BP 615 EP 618 DI 10.1016/S0008-8846(98)00201-4 PG 4 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 202BR UT WOS:000080632700025 ER PT J AU Helmig, D Klinger, LF Guenther, A Vierling, L Geron, C Zimmerman, P AF Helmig, D Klinger, LF Guenther, A Vierling, L Geron, C Zimmerman, P TI Biogenic volatile organic compound emissions (BVOCs) II. Landscape flux potentials from three continental sites in the US SO CHEMOSPHERE LA English DT Article ID STATES; FOREST AB Landscape nux potentials for biogenic volatile organic compounds (BVOCs) were derived for three ecosystems in the continental U.S. (Fembank Forest, Atlanta, GA; Willow Creek, Rhinelander, WI; Temple Ridge, CO). Analytical data from branch enclosure measurements were combined with ecological survey data for plant species composition and biomass. Other quantitative flux measurements at the leaf and landscape lever were incorporated to scale the results from the enclosure measurements to the landscape level. Flux estimates were derived by using a one week ambient temperature and light record (30 min time resolution) and adjusting all emission rates to these conditions with temperature and light correction algorithms. (C) 1999 Elsevier Science Ltd All nights reserved. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. US EPA, Res Triangle Pk, NC 27711 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Dept Environm Populat & Organ Biol, Boulder, CO 80309 USA. RP Helmig, D (reprint author), Univ Colorado, Dept Chem & Biochem, Campus Box 215, Boulder, CO 80309 USA. RI Vierling, Lee/E-6428-2010; Guenther, Alex/B-1617-2008; OI Vierling, Lee/0000-0001-5344-1983; Guenther, Alex/0000-0001-6283-8288; Geron, Chris/0000-0002-4266-2155 NR 11 TC 30 Z9 30 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-6535 J9 CHEMOSPHERE JI Chemosphere PD APR PY 1999 VL 38 IS 9 BP 2189 EP 2204 DI 10.1016/S0045-6535(98)00424-X PG 16 WC Environmental Sciences SC Environmental Sciences & Ecology GA 173LU UT WOS:000078982700020 PM 10101862 ER PT J AU Larson, DM Sutton, WR Terry, JM AF Larson, DM Sutton, WR Terry, JM TI Toward behavioral modeling of Alaska groundfish fisheries: A discrete choice approach to Bering Sea Aleutian Islands trawl fisheries SO CONTEMPORARY ECONOMIC POLICY LA English DT Article; Proceedings Paper CT 72nd Annual Conference of the Western-Economic-Association-International CY JUL 09-13, 1997 CL SEATTLE, WASHINGTON SP W Econ Assoc Int AB This article implements a discrete choice model of fishery participation in the multispecies trawl fisheries of the Bering Sea/Aleutian Islands Region off Alaska. Nonparametric estimates of the operation-specific moments of quasirent by fishery anti week are used to explain probabilities of choosing different target fisheries. There are pronounced risk aversion, seasonal, and relative performance effects. Notably, the model runs with regularly collected data, so this type of discrete choice modeling can be used routinely in the management and policy evaluation process. Improvements are needed, though, in both the quality and the extent of economic data on fisheries in Alaska and elsewhere in the United States. C1 Univ Calif Davis, Dept Agr & Resource Econ, Davis, CA 95616 USA. Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Resource Ecol & Fisheries Management Div, Socioecon Assessment Task Force, Seattle, WA USA. RP Larson, DM (reprint author), Univ Calif Davis, Dept Agr & Resource Econ, Davis, CA 95616 USA. NR 18 TC 12 Z9 12 U1 1 U2 3 PU WESTERN ECONOMIC ASSOC INT PI HUNTINGTON BEACH PA 7400 CENTER AVE SUITE 109, HUNTINGTON BEACH, CA 92647-3039 USA SN 1074-3529 J9 CONTEMP ECON POLICY JI Contemp. Econ. Policy PD APR PY 1999 VL 17 IS 2 BP 267 EP 277 PG 11 WC Economics; Public Administration SC Business & Economics; Public Administration GA 207CB UT WOS:000080916800012 ER PT J AU Bender, M Orchardo, J Dickson, ML Barber, R Lindley, S AF Bender, M Orchardo, J Dickson, ML Barber, R Lindley, S TI In vitro O-2 fluxes compared with C-14 production and other rate terms during the JGOFS Equatorial Pacific experiment SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID ISOTOPE-DILUTION; COMMUNITY PRODUCTION; CARBON; NITROGEN; PHYTOPLANKTON; OCEAN; 150-DEGREES-W; ASSIMILATION; PLANKTON; RELEASE AB We report rates of gross and net O-2 production measured in vitro during JGOFS cruises in the equatorial Pacific in spring and fall, 1992. We scale O-2 productivities to net and gross C production. We then compare the calculated rates with C-14 production and with new/export production measured by various techniques. C-14 productivities in samples incubated for 24 h are about 45% of gross carbon production rates calculated from gross O-2 production. The difference is compatible with expected rates of the Mehler reaction, photorespiration, excretion, and community mitochondrial respiration. C-14 production rates are similar to net carbon production rates in the upper half of the euphotic zone. At lower irradiances, where net C production can be zero or less, C-14 productivities lie between net community production and gross primary production. Net carbon production rates in vitro are a factor of similar to 4-20 times greater than estimates from drifting sediment trap and tracer transport studies. This difference probably reflects anomalous accumulation of POC in bottles because of the exclusion of grazers. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Rhode Isl, Grad Sch Oceanog, Kingston, RI 02881 USA. Duke Univ, Nicholas Sch Environm, Beaufort, NC 28156 USA. SW Fisheries Sci Ctr, Tiburon Lab, Tiburon, CA 94920 USA. RP Bender, M (reprint author), Princeton Univ, Dept Geosci, Guyot Hall, Princeton, NJ 08544 USA. RI Lindley, Steven/G-3997-2014 OI Lindley, Steven/0000-0001-9556-0411 NR 45 TC 95 Z9 96 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD APR PY 1999 VL 46 IS 4 BP 637 EP 654 DI 10.1016/S0967-0637(98)00080-6 PG 18 WC Oceanography SC Oceanography GA 180TY UT WOS:000079402300004 ER PT J AU Neuman, JA Huey, LG Ryerson, TB Fahey, DW AF Neuman, JA Huey, LG Ryerson, TB Fahey, DW TI Study of inlet materials for sampling atmospheric nitric acid SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID FILTER; HNO3; AIR AB The adsorption of nitric acid (HNO3) from a flowing gas stream is studied for a variety of wall materials to determine their suitability for use in atmospheric sampling instruments. Parts per billion level mixtures of HNO3 in synthetic air flow through tubes of different materials such that >80% of the molecules interact with the walls. A chemical ionization mass spectrometer with a fast time response and high sensitivity detects HNO3 that is not adsorbed on the tube walls. Less than 5% of available HNO3 is adsorbed on Teflon fluoropolymer tubing after 1 min of HNO3 exposure, whereas >70% is lost on walls made of stainless steel, glass, fused silica, aluminum, nylon, silica-steel, and silane-coated glass. Glass tubes exposed to HNO3 on the order of hours passivate with HNO3 adsorption dropping to zero. The adsorption of HNO3 on PFA Teflon tubing (PFA) is nearly temperature-independent from 10 to 80 degrees C, but below -10 degrees C nearly all HNO3 that interacts with PFA is reversibly adsorbed. In ambient and synthetic air, humidity increases HNO3 adsorption. The results suggest that Teflon at temperatures above 10 degrees C is an optimal choice for inlet surfaces used for in situ measurements of HNO3 in the ambient atmosphere. C1 NOAA, Aeron Lab, Environm Res Labs, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Neuman, JA (reprint author), NOAA, Aeron Lab, Environm Res Labs, 325 Broadway, Boulder, CO 80303 USA. RI Neuman, Andy/A-1393-2009; Ryerson, Tom/C-9611-2009; Fahey, David/G-4499-2013 OI Neuman, Andy/0000-0002-3986-1727; Fahey, David/0000-0003-1720-0634 NR 15 TC 118 Z9 118 U1 0 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD APR 1 PY 1999 VL 33 IS 7 BP 1133 EP 1136 DI 10.1021/es980767f PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 183FG UT WOS:000079543100041 ER PT J AU Buonaccorsi, VP Reece, KS Morgan, LW Graves, JE AF Buonaccorsi, VP Reece, KS Morgan, LW Graves, JE TI Geographic distribution of molecular variance within the blue marlin (Makaira nigricans): A hierarchical analysis of allozyme, single-copy nuclear DNA, and mitochondrial DNA markers SO EVOLUTION LA English DT Article DE allozyme; billfish; blue martin; comparative molecular evolution; genetic drift; Istiophoridae; Makaira nigricans; mitochondrial DNA; population genetics; single-copy nuclear DNA ID COD GADUS-MORHUA; POPULATION-STRUCTURE; AMERICAN OYSTER; GENE FLOW; CRASSOSTREA-VIRGINICA; ATLANTIC COD; HUMPBACK WHALES; PACIFIC-OCEAN; LOCI; POLYMORPHISMS AB This study presents a comparative hierarchical analysis of variance applied to three classes of molecular markers within the blue marlin (Makaira nigricans). Results are reported from analyses of four polymorphic allozyme loci, four polymorphic anonymously chosen single-copy nuclear DNA (scnDNA) loci, and previously reported restriction fragment length polymorphisms (RFLPs) of mitochondrial DNA (mtDNA). Samples were collected within and among the Atlantic and Pacific Oceans over a period of several years. Although moderate levels of genetic Variation were detected at both polymorphic allozyme (H = 0.30) and scnDNA loci (H = 0.37), mtDNA markers were: much more diverse (h = 0.85). Allele frequencies were significantly different between Atlantic and Pacific Ocean samples at three of four allozyme loci and three of four scnDNA loci. Estimates of allozyme genetic differentiation (theta(o)) ranged from 0.00 to 0.15, with a mean of 0.08. The theta(o) values for scnDNA loci were similar to those of allozymes, ranging from 0.00 to 0.12 with a mean of 0.09. MtDNA RFLP divergence between oceans (theta(o) = 0.39) was significantly greater than divergence detected at nuclear loci (95% nuclear confidence interval = 0.04-0.11). The fourfold smaller effective population size of mtDNA and male-mediated gene Bow may account for the difference observed between nuclear and mitochondrial divergence estimates. C1 Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. RP Buonaccorsi, VP (reprint author), Natl Marine Fisheries Serv, 8604 La Jolla Shores Dr, La Jolla, CA 92038 USA. NR 84 TC 36 Z9 37 U1 0 U2 9 PU SOC STUDY EVOLUTION PI LAWRENCE PA 810 E 10TH STREET, LAWRENCE, KS 66044 USA SN 0014-3820 J9 EVOLUTION JI Evolution PD APR PY 1999 VL 53 IS 2 BP 568 EP 579 DI 10.2307/2640793 PG 12 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 195AN UT WOS:000080227100026 ER PT J AU Heifetz, J Anderl, D Maloney, NE Rutecki, TL AF Heifetz, J Anderl, D Maloney, NE Rutecki, TL TI Age validation and analysis of ageing error from marked and recaptured sablefish, Anoplopoma fimbria SO FISHERY BULLETIN LA English DT Article AB Sablefish, Anoplopoma fimbria, are especially difficult to age. Ages are typically determined by counting growth zones that are assumed to be annuli on the burnt cross section of an otolith. We evaluated the accuracy of ageing methods by comparing the ages obtained from two experienced age readers with those ages that were known. A mark-recapture experiment on sablefish provided a relatively large sample (n=49) of 2-9 year old sablefish. This sample of known-age fish provided a unique opportunity to evaluate the accuracy of ageing methods for young sablefish. Our study generally confirmed the criteria used to age young sablefish. According to the assignment of ages from two experienced age readers, about two-thirds of the fish were misaged. Of these, most fish (81% and 71% for the two readers) were misaged by only one year. After reexamination of the otoliths, most of the discrepancies between reader age and known age could be resolved. Ageing-error matrices that define the probability of assigning an age to a fish of a given true age were estimated from among-reader variability and from comparison of known ages to reader ages. Estimates of ageing errors, based on comparison of known ages to reader ages, were considerably higher than estimates obtained from among-reader variability. We recommend that ageing-error corrections applied in stock assessment models be based on the ageing-error matrix derived from known and reader ages. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Heifetz, J (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM jon.heifetz@noaa.gov NR 17 TC 13 Z9 14 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 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1999 VL 97 IS 2 BP 256 EP 263 PG 8 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600004 ER PT J AU Krieger, KJ Ito, DH AF Krieger, KJ Ito, DH TI Distribution and abundance of shortraker rockfish, Sebastes borealis and rougheye rockfish, S-aleutianus, determined from a manned submersible SO FISHERY BULLETIN LA English DT Article AB A manned submersible was used in the eastern Gulf of Alaska in 1992 to observe spatial distributions and habitats of shortraker rockfish, Sebastes borealis, and rougheye rock-fish, S. aleutianus, on the continental slope at 262-365 m depths. Observations of these two species were combined because distinguishing between them was not always possible from the submersible. A seafloor area of 104,900 m(2) was surveyed at 15 dive sites, and 646 shortraker and rougheye rockfish were observed. Densities were 0.0 to 14.8 rockfish/1000 m(2) (mean, 5.8 rockfish/1000 m(2)). Of the 646 rockfish, 115 were observed above bottom and 531 were on the bottom. The above-bottom rockfish were descending slowly to the seafloor and became sedentary when they contacted the seafloor. Approximately two-thirds of the rockfish were in groups; 82 of the 113 groups contained 2 or 3 rockfish, and only 2 groups had more than 12 rockfish. Rockfish were associated with 20 of the 22 substrates encountered. Soft substrates of sand or mud usually had the greatest densities of rockfish, whereas hard substrates of bedrock, cobble, or pebble usually had the least densities. Habitats containing steep slopes and numerous boulders had greater densities of rockfish than habitats with gradual slopes and few boulders; 52 rockfish lay against boulders. According to catch rates from bottom-trawl surveys, populations of shortraker and rougheye rockfish may be underestimated because of the above-bottom distribution of these rockfish and their use of steep-slope boulder habitats. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Krieger, KJ (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 13 TC 19 Z9 20 U1 1 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 1999 VL 97 IS 2 BP 264 EP 272 PG 9 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600005 ER PT J AU MacFarlane, RB Norton, EC AF MacFarlane, RB Norton, EC TI Nutritional dynamics during embryonic development in the viviparous genus Sebastes and their application to the assessment of reproductive success SO FISHERY BULLETIN LA English DT Article ID LIPID CLASS COMPOSITION; COD GADUS-MORHUA; YELLOWTAIL ROCKFISH; ENERGY-METABOLISM; LARVAL FISH; CALIFORNIA ROCKFISHES; DEVELOPING EGGS; RED DRUM; FLAVIDUS; STARVATION AB Concentrations of lipids and protein were measured in embryos during gestation in two species of viviparous rockfishes off the central California coast. Total lipids and protein declined linearly through embryonic maturation in semipelagic yellowtail rockfish, Sebastes flavidus, and pelagic shortbelly rockfish, Sebastes jordani. Energetically, lipids were the predominant source of energy for embryonic development in both species, but lipid and protein catabolism was significantly greater for yellowtail rockfish. Total lipids, protein, and lipid class composition were measured during embryonic maturation in three populations of shortbelly rockfish, located at Ascension, Pioneer, and Bodega submarine canyons, to determine intraspecific variability of nutritional dynamics. Triacylglycerols and polar lipids (mostly phospholipids), the predominant lipid classes in all maturation stages, were depleted through embryonic development. Steryl or wax esters and cholesterol also declined, but were in much lower concentrations. The goodness-of-fit of linear regressions for protein, total lipid, and lipid classes by stage of embryonic maturation allowed estimations of their concentrations at birth, thus providing a measure of nutritional condition, or qualitative reproductive success. Analyses determined that there were significant differences in metabolism and estimated concentrations at birth of nutrients between the two species and among the shortbelly rockfish populations, indicating differential potential for survival during early planktonic life stages until favorable feeding conditions occur. Results suggest that the contribution of individual populations to the diversity of metapopulations or year classes may be influenced by the nutritional condition of larvae at birth. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, Tiburon, CA 94920 USA. RP MacFarlane, RB (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, 3150 Paradise Dr, Tiburon, CA 94920 USA. EM Bruce.MacFarlane@noaa.gov NR 44 TC 13 Z9 13 U1 0 U2 3 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 1999 VL 97 IS 2 BP 273 EP 281 PG 9 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600006 ER PT J AU Terwilliger, MR Munroe, TA AF Terwilliger, MR Munroe, TA TI Age, growth, longevity, and mortality of blackcheek tonguefish, Symphurus plagiusa (Cynoglossidae : Pleuronectiformes), in Chesapeake Bay, Virginia SO FISHERY BULLETIN LA English DT Article ID LIFE-HISTORY PATTERNS; FLATFISH; BIOLOGY; REPRODUCTION; PARAMETERS; POPULATION; FISHES; WATERS; SOLE AB Age structure, longevity, and mortality were determined for a population of blackcheek tonguefish, Symphurus plagiusa, in Chesapeake Bay. Blackcheek tonguefish (36-202 mm TL) were randomly collected by means of otter trawl in lower Chesapeake Bay and major Virginia tributaries (James, York, and Rappahannock rivers) from April 1994 through August 1995. Ages were determined by interpreting growth increments on thin transverse sections of sagittal otoliths. Marginal increment analysis showed that a single annulus was formed in June of each year. Blackcheek tonguefish caught during this study reached a maximum age of 5+ years. Growth was rapid during the first year, then slowed rapidly at a time coincident with maturation. We used the following von Bertalanffy growth equations: for males-L-t = 196.5(1- e(-0.285(t + 0.92))); and for females-L-t = 190.6(1 - e(-0.320(t + 0.78))). Von Bertalanffy parameters were not significantly different between sexes. Extrapolated instantaneous mortality rates for a possible seventh year class were 0.73 (Hoenig's equation) and 0.77 (Royce's equation). High estimates of instantaneous total mortality may reflect either loss due to emigration of adults from Chesapeake Bay onto the continental shelf or high natural mortality occurring in this northernmost population. Compared with sympatric pleuronectiforms, blackcheek tonguefish have a relatively high mortality rate, small asymptotic length, and high growth parameter K. Species, such as blackcheek tonguefish, that feature this combination of growth parameters are hypothesized to be better adapted at exploiting seasonally dynamic and highly unpredictable environments, such as those estuarine habitats within Chesapeake Bay. C1 Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. Natl Museum Nat Hist, Natl Marine Fisheries Serv, Natl Systemat Lab, Washington, DC 20560 USA. RP Terwilliger, MR (reprint author), Oregon State Univ, Dept Fisheries & Wildlife, 104 Nash Hall, Corvallis, OR 97331 USA. EM terwillm@ucs.orst.edu NR 82 TC 11 Z9 12 U1 1 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 J9 FISH B-NOAA JI Fish. Bull. PD APR PY 1999 VL 97 IS 2 BP 340 EP 361 PG 22 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600012 ER PT J AU Carlson, JK AF Carlson, JK TI Occurrence of neonate and juvenile sandbar sharks, Carcharhinus plumbeus, in the northeastern Gulf of Mexico SO FISHERY BULLETIN LA English DT Article ID CHINCOTEAGUE BAY; VIRGINIA; GROWTH; AGE C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Panama City, FL 32408 USA. RP Carlson, JK (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. NR 16 TC 15 Z9 22 U1 1 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 1999 VL 97 IS 2 BP 387 EP 391 PG 5 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600016 ER PT J AU Holland, KN Kleiber, P Kajiura, SM AF Holland, KN Kleiber, P Kajiura, SM TI Different residence times of yellowfin tuna, Thunnus albacares, and bigeye tuna, T-obesus, found in mixed aggregations over a seamount SO FISHERY BULLETIN LA English DT Article C1 Hawaii Inst Marine Biol, Kaneohe, HI 96744 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Hawaii Manoa, Dept Zool, Honolulu, HI 96822 USA. RP Holland, KN (reprint author), Hawaii Inst Marine Biol, Coconut Isl, Kaneohe, HI 96744 USA. NR 10 TC 36 Z9 40 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 1999 VL 97 IS 2 BP 392 EP 395 PG 4 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600017 ER PT J AU Yang, MS Page, BN AF Yang, MS Page, BN TI Diet of Pacific sleeper shark, Somniosus pacificus, in the Gulf of Alaska SO FISHERY BULLETIN LA English DT Article C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Yang, MS (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 11 TC 11 Z9 12 U1 2 U2 8 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 1999 VL 97 IS 2 BP 406 EP 409 PG 4 WC Fisheries SC Fisheries GA 183VV UT WOS:000079575600020 ER PT J AU Antonopoulou, E Bornestaf, C Swanson, P Borg, B AF Antonopoulou, E Bornestaf, C Swanson, P Borg, B TI Feedback control of gonadotropins in Atlantic salmon, Salmo salar, male parr - I. Castration effects in rematuring and nonrematuring fish SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID TROUT ONCORHYNCHUS-MYKISS; RAINBOW-TROUT; GTH-II; REPRODUCTIVE-CYCLE; PLASMA-LEVELS; PITUITARY GONADOTROPINS; COHO SALMON; 5 ANDROGENS; SECRETION; GAIRDNERI AB Sexual maturation of Atlantic salmon (Salmo salar) male parr is a seasonally recurrent "all or none" response; either a fish matures fully or it does not mature. To study whether gonadal feedback on gonadotropic hormones, GTH I and GTH II, is involved in the control of maturation, previously mature Atlantic salmon male parr were either sham-operated or castrated in spring. They were then sampled during the onset of gonadal growth (late June-early July) or shortly before the breeding season (late September). In autumn, sham-operated males separated into two groups: nonrematuring males with low pituitary and plasma levels of both GTH I and GTH II, and those rematuring with high levels of gonadotropins. Castrated males had low GTH I and GTH II plasma and pituitary levels, similar to those of the nonrematuring fish, suggesting positive feedback mechanisms, separating the sham-operated fish into low and high GTH level groups. In the summer, plasma GTH II was nondetectable in all fish. Pituitary GTH II content was lower in nonrematuring, than in rematuring males and was even lower in castrated fish. In contrast, castration increased pituitary and plasma levels of GTH I in the summer, suggesting a negative feedback at this reproductive stage. There were no significant differences in immunoassayable levels of GTH I in plasma in rematuring and nonrematuring sham-operated males at this time. The control of rematuration is complex and may involve factors other than circulating GTH I levels, possibly with differences in gonadal sensitivity to GTH I. (C) 1999 Academic Press. C1 Univ Stockholm, Dept Zool, S-10691 Stockholm, Sweden. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Antonopoulou, E (reprint author), Univ Rennes 1, UPRESA CNRS 6026, Campus de Beaulieu, F-35042 Rennes, France. RI Antonopoulou, Efthimia/N-4233-2015; OI Antonopoulou, Efthimia/0000-0003-4565-6962 NR 22 TC 15 Z9 15 U1 0 U2 3 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 1999 VL 114 IS 1 BP 132 EP 141 DI 10.1006/gcen.1998.7249 PG 10 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 185CL UT WOS:000079650500014 PM 10094866 ER PT J AU Antonopoulou, E Swanson, P Mayer, I Borg, B AF Antonopoulou, E Swanson, P Mayer, I Borg, B TI Feedback control of gonadotropins in Atlantic salmon, Salmo salar, male parr - II. Aromatase inhibitor and androgen effects SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article ID TROUT ONCORHYNCHUS-MYKISS; BETA SUBUNIT GENE; RAINBOW-TROUT; GTH-II; PLASMA-LEVELS; PITUITARY GONADOTROPIN; REPRODUCTIVE-CYCLE; IN-VITRO; GONADECTOMY; MATURATION AB Both positive and negative feedback on the (hypothalmus)-pituitary-gonad axis occur in salmonids. The aim of the present study was to investigate the role of different androgens, and in particular the involvement of aromatization of androgens to estrogens in feedback mechanisms. Previously mature Atlantic salmon, Salmo salar, male parr were studied in two experiments. In the first experiment, intact fish were implanted with Silastic capsules filled with the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD) in spring and sampled in the autumn when the rematuring males were starting to display running milt. In the second experiment, castrated males were implanted with capsules containing ATD, the androgens testosterone (T) and 11-ketoandrostenedione (11KA), or ATD and T combined in spring. These fish were sampled in the summer when rematuring fish were starting to show signs of gonadal growth. Pituitary and plasma gonadotropins (GTH I and GTH II) were studied using radioimmunoassay. In autumn, ATD treatment reduced pituitary and plasma GTH II levels. In summer, GTH II was consistently nondetectable in plasma. Castration diminished pituitary GTH II content. Treatment with T increased pituitary GTH II content, an effect that was attenuated when T treatment was combined with ATD. All these results are consistent with the presence of an aromatase-dependent positive feedback of T on GTH II. 11KA also had a stimulatory effect on GTH II, although weaker than that of T. Testicular size and spermiation was reduced by ATD in autumn; the latter of these results is likely to be due to the inhibitory effect of ATD on GTH II. Positive effects of ATD on plasma GTH I were found in autumn, indicative of an aromatase-dependent negative feedback in this phase. On the other hand, castration increased plasma and pituitary GTH I levels in summer, indicating that the gonads in this phase exert a predominantely negative control of GTH I. In summer, negative effects of T on GTH I pituitary levels were not suppressed, but were rather enhanced, by the combined treatment with ATD, Furthermore, plasma GTH I levels were lower after treatment with T in combination with ATD than with T or ATD separately. These negative effects of T were not diminished by ATD, so that they are nonaromatase-dependent. Furthermore, since they were actually more pronounced in the presence of ATD it is suggested that there is also a positive aromatase-dependent feedback component in this phase. In addition, 11KA had a negative effect on plasma and pituitary GTH I in castrated previously mature males, Thus, GTH I secretion is controlled by both aromatase-dependent and nonaromatase-dependent feedback effects, of which at least the former may be positive or negative depending on season, In summary, the feedback control of GTH I appears to be more complex than that of GTH II. (C) 1999 Academic Press. C1 Univ Stockholm, Dept Zool, S-10691 Stockholm, Sweden. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Antonopoulou, E (reprint author), Univ Rennes 1, UPRESA CNRS 6026, Campus de Beaulieu, F-35042 Rennes, France. RI Antonopoulou, Efthimia/N-4233-2015; OI Antonopoulou, Efthimia/0000-0003-4565-6962 NR 29 TC 45 Z9 45 U1 1 U2 6 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 1999 VL 114 IS 1 BP 142 EP 150 DI 10.1006/gcen.1998.7248 PG 9 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 185CL UT WOS:000079650500015 PM 10094867 ER PT J AU de Gouw, JA Howard, CJ Custer, TG Fall, R AF de Gouw, JA Howard, CJ Custer, TG Fall, R TI Emissions of volatile organic compounds from cut grass and clover are enhanced during the drying process SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GAS-PHASE REACTIONS; HYDROCARBONS; RADICALS; OZONE; CIS-3-HEXEN-1-OL; TROPOSPHERE; O-3; OH AB The release of volatile organic compounds (VOCs) by drying grass and clover leaves and stems was studied in the laboratory using proton-transfer chemical-ionization mass spectrometry, which enables the simultaneous, on-line monitoring of VOC concentrations. A burst of VOC emissions due to cutting the leaves and stems was followed by a second, more intense emission lasting for several hours when the vegetation was starting to dry out. In addition to (2)-3-hexenal, (Z)-3-hexenol, and hexenyl acetate, that were emitted by the plans tissue in response to the wounding, enhanced emissions of methanol, acetaldehyde, acetone, butanone, and possibly formaldehyde were observed. These findings may have important implications for regional air quality in agricultural and urban areas. C1 NOAA, Aeron Lab, Environm Res Labs, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP de Gouw, JA (reprint author), Univ Utrecht, Dept Phys & Astron, PO Box 80000, NL-3508 TA Utrecht, Netherlands. RI de Gouw, Joost/A-9675-2008 OI de Gouw, Joost/0000-0002-0385-1826 NR 22 TC 92 Z9 92 U1 0 U2 8 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 1999 VL 26 IS 7 BP 811 EP 814 DI 10.1029/1999GL900076 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 182AW UT WOS:000079477200001 ER PT J AU Koshyk, JN Hamilton, K Mahlman, JD AF Koshyk, JN Hamilton, K Mahlman, JD TI Simulation of the k(-5/3) mesoscale spectral regime in the GFDL SKYHI general circulation model SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AIRCRAFT N2O MEASUREMENTS; STRATIFIED TURBULENCE; ATMOSPHERIC ENERGY; VARIABILITY; CASCADES; WAVES AB Data from very high horizontal resolution simulations with the Geophysical Fluid Dynamics Laboratory SKYHI general circulation model are used to calculate the kinetic energy spectrum as a function of horizontal wavenumber, k, in the upper troposphere. The spectrum shows the familiar similar to -3 slope at scales longer than similar to 1000 km, in agreement with previous general circulation model and observational studies. At shorter scales, the spectrum becomes shallower with a slope similar to -5/3, also in agreement with available observations. The -5/3 slope spans about a decade of the resolved scales and this result represents the first successful simulation of such a broad range of the mesoscale regime by a global model. Partitioning of the flow between rotational and divergent components shows that the rotational part dominates at large scales and that there is approximate equipartition between rotational and divergent parts at mesoscales. Analysis of the parameterized kinetic energy dissipation shows that vertical diffusion dominates horizontal diffusion for a wide range of wavenumbers extending well into the k(-5/3) regime. C1 Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Koshyk, JN (reprint author), Univ Toronto, Dept Phys, 60 St George St, Toronto, ON M5S 1A7, Canada. NR 28 TC 39 Z9 40 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD APR 1 PY 1999 VL 26 IS 7 BP 843 EP 846 DI 10.1029/1999GL900128 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 182AW UT WOS:000079477200009 ER PT J AU Joussaume, S Taylor, KE Braconnot, P Mitchell, JFB Kutzbach, JE Harrison, SP Prentice, IC Broccoli, AJ Abe-Ouchi, A Bartlein, PJ Bonfils, C Dong, B Guiot, J Herterich, K Hewitt, CD Jolly, D Kim, JW Kislov, A Kitoh, A Loutre, MF Masson, V McAvaney, B McFarlane, N de Noblet, N Peltier, WR Peterschmitt, JY Pollard, D Rind, D Royer, JF Schlesinger, ME Syktus, J Thompson, S Valdes, P Vettoretti, G Webb, RS Wyputta, U AF Joussaume, S Taylor, KE Braconnot, P Mitchell, JFB Kutzbach, JE Harrison, SP Prentice, IC Broccoli, AJ Abe-Ouchi, A Bartlein, PJ Bonfils, C Dong, B Guiot, J Herterich, K Hewitt, CD Jolly, D Kim, JW Kislov, A Kitoh, A Loutre, MF Masson, V McAvaney, B McFarlane, N de Noblet, N Peltier, WR Peterschmitt, JY Pollard, D Rind, D Royer, JF Schlesinger, ME Syktus, J Thompson, S Valdes, P Vettoretti, G Webb, RS Wyputta, U TI Monsoon changes for 6000 years ago: Results of 18 simulations from the Paleoclimate Modeling Intercomparison Project (PMIP) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LAKE STATUS DATA; NORTHERN AFRICA; MIDDLE HOLOCENE; CLIMATE; BP; VARIABILITY; FEEDBACKS; CIRCULATION; MIDHOLOCENE; SENSITIVITY AB Amplification of the northern hemisphere seasonal cycle of insolation during the mid-Holocene causes a northward shift of the main regions of monsoon precipitation over Africa and India in all 18 simulations conducted for the Paleoclimate Modeling Intercomparison Project (PMIP). Differences among simulations are related to differences in model formulation. Despite qualitative agreement with paleoecological estimates of biome shifts, the magnitude of the monsoon increases over northern Africa are underestimated by all the models. C1 CEA Saclay, CNRS, UMR 1572, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. Univ Calif Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. Hadley Ctr, Bracknell, Berks, England. Univ Wisconsin, Ctr Climat Res, Madison, WI 53706 USA. Univ Lund, S-22100 Lund, Sweden. Max Planck Inst Biogeochem, Jena, Germany. Univ Lund, Sch Ecol, Lund, Sweden. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. Univ Oregon, Dept Geog, Eugene, OR 97403 USA. Univ Reading, Dept Meteorol, Reading, Berks, England. Fac Sci St Jerome, CNRS, IMEP, Marseille, France. Univ Bremen, Bremen, Germany. Yonsei Univ, Seoul 120749, South Korea. Univ Moscow, Dept Meteorol & Climatol, Moscow, Russia. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Catholic Univ Louvain, Inst Astron & Geophys, B-3000 Louvain, Belgium. Res Ctr, Bur Meteorol, Melbourne, Vic, Australia. Univ Toronto, Dept Atmospher Sci, Toronto, ON, Canada. Penn State Univ, Ctr Earth Syst Sci, University Pk, PA 16802 USA. Ctr Natl Rech Meteorol, Toulouse, France. Univ Illinois, Dept Atmospher Sci, Chicago, IL 60680 USA. CSIRO, Div Atmospher Res, Canberra, ACT, Australia. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Geophys Data Ctr, Boulder, CO USA. RP Joussaume, S (reprint author), CEA Saclay, CNRS, UMR 1572, Lab Sci Climat & Environm, Bat 709, F-91191 Gif Sur Yvette, France. EM joussaume@cea.fr; taylor13@llnl.gov RI Bonfils, Celine/H-2356-2012; Bartlein, Patrick/E-4643-2011; Syktus, Jozef/E-7173-2011; Taylor, Karl/F-7290-2011; Peltier, William/A-1102-2008; Masson-Delmotte, Valerie/G-1995-2011; Valdes, Paul/C-4129-2013; Abe-Ouchi, Ayako/M-6359-2013; Broccoli, Anthony/D-9186-2014; Guiot, Joel/G-7818-2011; de NOBLET, Nathalie/O-8613-2015 OI Loutre, Marie-France/0000-0001-6944-4038; Harrison, Sandy/0000-0001-5687-1903; Dong, Buwen/0000-0003-0809-7911; Bonfils, Celine/0000-0002-4674-5708; Bartlein, Patrick/0000-0001-7657-5685; Syktus, Jozef/0000-0003-1782-3073; Taylor, Karl/0000-0002-6491-2135; Masson-Delmotte, Valerie/0000-0001-8296-381X; Abe-Ouchi, Ayako/0000-0003-1745-5952; Broccoli, Anthony/0000-0003-2619-1434; Guiot, Joel/0000-0001-7345-4466; NR 29 TC 250 Z9 273 U1 5 U2 35 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 1999 VL 26 IS 7 BP 859 EP 862 DI 10.1029/1999GL900126 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 182AW UT WOS:000079477200013 ER PT J AU Henson, WK Ahmed, KZ Vogel, EM Hauser, JR Wortman, JJ Venables, RD Xu, M Venables, D AF Henson, WK Ahmed, KZ Vogel, EM Hauser, JR Wortman, JJ Venables, RD Xu, M Venables, D TI Estimating oxide thickness of tunnel oxides down to 1.4 nm using conventional capacitance-voltage measurements on MOS capacitors SO IEEE ELECTRON DEVICE LETTERS LA English DT Article AB High-frequency capacitance-voltage (C-V) measurements have been made on ultrathin oxide metal-oxide-semiconductor (MOS) capacitors. The sensitivity of extracted oxide thickness to series resistance and gate leakage is demonstrated. Guidelines are outlined for reliable and accurate estimation of oxide thickness from C-V measurements for oxides down to 1.4 nm. C1 N Carolina State Univ, Dept Elect & Comp Engn, Raleigh, NC 27695 USA. Adv Micron Devices, Sunnyvale, CA 94088 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. RP Henson, WK (reprint author), N Carolina State Univ, Dept Elect & Comp Engn, Raleigh, NC 27695 USA. RI Vogel, Eric/A-7731-2008 OI Vogel, Eric/0000-0002-6110-1361 NR 6 TC 129 Z9 131 U1 0 U2 15 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0741-3106 J9 IEEE ELECTR DEVICE L JI IEEE Electron Device Lett. PD APR PY 1999 VL 20 IS 4 BP 179 EP 181 DI 10.1109/55.753759 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 181MG UT WOS:000079444700011 ER PT J AU Voronovich, AG Shang, EC AF Voronovich, AG Shang, EC TI Horizontal refraction modal tomography of the ocean with mode interactions SO IEEE JOURNAL OF OCEANIC ENGINEERING LA English DT Article DE acoustic tomography; remote sensing ID ACOUSTIC TOMOGRAPHY AB The acoustical tomography scheme for inferring a three-dimensional sound-speed field within some area based on the measurements of horizontal refraction angles is reviewed, The numerical simulations made so far were based on the assumption of the adiabaticity of low-frequency mode propagation, In this paper, an inversion scheme is presented that accounts for the acoustic mode interaction, We found that, generally, the interaction weakly affects the horizontal refraction angle, and it can be accounted for by iterations. Numerical simulations for the case of an Atlantic "meddy" corresponding to a strong double-channel stratification are presented, Only three iterations were required to retrieve the exact strong sound-speed-field inhomogeneity within an area of 500 km x 500 km. C1 Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Voronovich, AG (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. NR 14 TC 2 Z9 3 U1 1 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0364-9059 J9 IEEE J OCEANIC ENG JI IEEE J. Ocean. Eng. PD APR PY 1999 VL 24 IS 2 BP 224 EP 231 DI 10.1109/48.757273 PG 8 WC Engineering, Civil; Engineering, Ocean; Engineering, Electrical & Electronic; Oceanography SC Engineering; Oceanography GA 188VG UT WOS:000079869000008 ER PT J AU Baker-Jarvis, J Riddle, B Young, AM AF Baker-Jarvis, J Riddle, B Young, AM TI Ion dynamics near charged electrodes with excluded volume effect SO IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION LA English DT Article ID POISSON-BOLTZMANN CALCULATIONS; DNA AB The goal of this paper is to analyze ion relaxation around a charged electrode taking into account finite ion volume and frequency. Time-dependent and electrostatic equations for ion behavior near an electrode are developed and include the effects of nonequilibrium and steric hindrance. Time-dependent wave equations for the potentials are developed in the Lorentz gauge. The charge density is expressed as a sum of the quasi-steady state solution plus a nonequilibrium term. For slowly changing potentials the ions are in quasi equilibrium and we show that in this limit the potential satisfies the sinh-Gordon equation. New solutions to this nonlinear time-dependent equation are developed. In the low voltage limit the equation reduces to the Klein-Gordon equation, time-dependent analog of the Debye-Huckel equation. We also present equations for capacitance and surface charge. C1 Natl Inst Stand & Technol, Radio Frequency Technol Div, Boulder, CO USA. MIT, Lincoln Lab, Cambridge, MA 02139 USA. RP Baker-Jarvis, J (reprint author), Natl Inst Stand & Technol, Radio Frequency Technol Div, 325 Broadway, Boulder, CO USA. NR 11 TC 7 Z9 7 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1070-9878 J9 IEEE T DIELECT EL IN JI IEEE Trns. Dielectr. Electr. Insul. PD APR PY 1999 VL 6 IS 2 BP 226 EP 235 DI 10.1109/94.765913 PG 10 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 201BW UT WOS:000080575600012 ER PT J AU Belecki, NB AF Belecki, NB TI Special issue on selected papers presented at the CPEM'98 SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Editorial Material C1 Natl Inst Stand & Technol, Div Elect, Gaithersburg, MD 20899 USA. RP Belecki, NB (reprint author), Natl Inst Stand & Technol, Div Elect, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 150 EP 151 PG 2 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600001 ER PT J AU Bell, BA AF Bell, BA TI Special issue on selected papers presented at the CPEM'98 SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Editorial Material C1 Natl Inst Stand & Technol, Elect Instrumentat & Metrol Grp, Gaithersburg, MD 20899 USA. RP Bell, BA (reprint author), Natl Inst Stand & Technol, Elect Instrumentat & Metrol Grp, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 152 EP 153 DI 10.1109/TIM.1999.769550 PG 2 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600002 ER PT J AU Achkar, J Velasco, L Weidman, MP Clark, RF Kim, JH Park, JI Zhang, T Peters, JE Ruehaak, J Stumpe, D de Vreede, JPM Wallace, AM AF Achkar, J Velasco, L Weidman, MP Clark, RF Kim, JH Park, JI Zhang, T Peters, JE Ruehaak, J Stumpe, D de Vreede, JPM Wallace, AM TI International comparison of power measurements at 33 GHz (GT-RF/92-4) SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE attenuation measurement; measurement standards; power measurement; temperature measurement; thermistors; transfer standards; uncertainty; waveguides ID RF AB A measurement comparison of effective efficiency has been carried out between eight national metrology laboratories at 33 GHz in rectangular waveguide TEC R320,Two waveguide thermistor mounts were measured. The following national laboratories participated: BNM-LCIE (France), NIST (U.S.), NRC (Canada), KRISS (Korea), CSIRO (Australia), PTB (Germany), NMi VSL (The Netherlands), and NPL (U.K.). The Bureau National de Metrologie-Laboratoire Central des Industries Electriques (France) acted as the pilot laboratory for the comparison. Excellent harmony is observed between results given by the participants, especially for the item LCIE-92021. C1 BNM LCIE, F-92266 Fontenay Aux Roses, France. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Natl Res Council Canada, Ottawa, ON K1A 0R6, Canada. Korea Res Inst Stand & Sci, Taejon 305606, South Korea. CSIRO, Lindfield, NSW 2070, Australia. Phys Tech Bundesanstalt, D-38023 Braunschweig, Germany. NMi Van Swinden Lab, NL-2600 AR Delft, Netherlands. Natl Phys Lab, Teddington TW11 0LW, Middx, England. RP Achkar, J (reprint author), BNM LCIE, F-92266 Fontenay Aux Roses, France. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 169 EP 173 DI 10.1109/19.769555 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600007 ER PT J AU Randa, J Achkar, J Buchholz, FI Colard, T Rice, J Schubert, D Sinclair, M Williams, GL AF Randa, J Achkar, J Buchholz, FI Colard, T Rice, J Schubert, D Sinclair, M Williams, GL TI International comparison of thermal noise-temperature measurements at 2, 4, and 12 GHz SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE international comparison; noise; noise measurement; noise temperature; thermal noise ID STANDARD; POWER AB We discuss an international comparison of thermal noise-power measurements (GTRF-92-2), which has recently been completed under the auspices of the Consultative Committee for Electricity and Magnetism (CCEM). The noise temperatures of two solid-state sources with GPC-7 connectors were measured at 2,4, and 12 GHz at the national laboratories in France, Germany, the United Kingdom, and the United States. Good agreement was found among the results from the different laboratories, with all results agreeing within the expanded uncertainties, which ranged from approximately 0.5% to 2.9%. The comparison was performed in accordance with the guidelines recently adopted by the Bureau International des Poids et Mesures (BIPM). C1 Natl Inst Stand & Technol, Boulder, CO 80301 USA. Lab Cent Ind Elect, Fontenay Aux Roses, France. Phys Tech Bundesanstalt, D-3300 Braunschweig, Germany. RP Randa, J (reprint author), Natl Inst Stand & Technol, Boulder, CO 80301 USA. NR 10 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 174 EP 177 DI 10.1109/19.769556 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600008 ER PT J AU Jentschura, UD Mohr, PJ Soff, G AF Jentschura, UD Mohr, PJ Soff, G TI Numerical evaluation of the lamb shift in hydrogen SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE fundamental constants; quantum electrodynamics; relativistic and QED effects ID FREQUENCY; DEUTERIUM AB A reliable and precise theoretical understanding of quantum electrodynamic effects in atoms is of crucial importance for the determination of fundamental constants from precision electromagnetic measurements. The numerical evaluation of self-energy corrections in hydrogen-like ions with small atomic number Z entails severe loss of numerical significance at intermediate stages of the calculation and slow convergence in the sum over intermediate angular momenta, We present an evaluation of the scaled self-energy function F(Z alpha) at Z = 1 with a relative uncertainty of 2 x 10(-9). C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden, Germany. RP Jentschura, UD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 12 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 186 EP 188 DI 10.1109/19.769559 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600011 ER PT J AU Heavner, TP Jefferts, SR Dunn, GH AF Heavner, TP Jefferts, SR Dunn, GH TI Precision measurement of the atomic mass of Li-6 using a Penning ion trap mass spectrometer SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE atomic measurements; mass spectroscopy AB We have used a cryogenic (JK) Penning ion trap mass spectrometer to measure the mass ratios of Li-6(+)/C-12(2+) Li-6(+)/D-3(+), and D-2(+)/He+. We developed techniques to create ions outside of the cryogenic trap environment and to transport them into the trap where a small number (1-10) mere confined. The ions' frequencies of oscillation were measured using a high-Q tuned circuit to detect image currents induced in the trap electrodes. The measurements involving Li-6(+) result in a value for the atomic mass of Li-6 of 6.015 122 795(16) u, with a fractional uncertainty of +/-2.7x10(-9) representing a factor of 30 improvement over the published, tabulated value, A measurement of the D-2(+)/He+ mass ratio has an uncertainty of +/-1.1 x 10(-9) and is within 0.6x10(-9) of the tabulated value, thus demonstrating that our techniques are reliable. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Heavner, TP (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 8 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 189 EP 191 DI 10.1109/19.769560 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600012 ER PT J AU Steiner, RL Newell, DB Williams, ER AF Steiner, RL Newell, DB Williams, ER TI A result from the NIST watt balance and an analysis of uncertainties SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE measurement units; SI power units; SI watt measurement; watt balance; watt ratio measurement ID EQUATION; AIR AB An improved determination of the ratio of power, measured in terms of the Josephson and quantum Hall effects, and also the meter, kilogram, and second, has been completed. The result is expressed as: W-90/W = 1 + (8 +/- 87) x 10(-9). This is an order of magnitude improvement from the fast NIST (formerly NBS) determination. The Type A relative standard uncertainty (statistical) is 30 nW/W, and the Type B relative standard uncertainty is 82 n W/W. Type B uncertainty components are listed and discussed within the contest of experimental procedure descriptions. Improvements for the next version of this experiment are also mentioned. C1 Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Technol Adm,US Dept Commerce, Gaithersburg, MD 20899 USA. RP Steiner, RL (reprint author), Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Technol Adm,US Dept Commerce, Gaithersburg, MD 20899 USA. NR 8 TC 13 Z9 13 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 205 EP 208 DI 10.1109/19.769564 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600016 ER PT J AU Kessler, EG Owens, SM Henins, A Deslattes, RD AF Kessler, EG Owens, SM Henins, A Deslattes, RD TI Silicon lattice comparisons related to the Avogadro project: Uniformity of new material and surface preparation effects SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE Avogadro constant; crystal lattice comparison; silicon; surface preparation; X-ray diffraction; X-ray measurements AB New high-quality silicon has been produced by Wacker Siltronics(1) as potential starting material for a precision determination of the Avogadro constant, N-A. An assessment of the uniformity of this material is an essential first step in determining whether this material is of sufficient quality to be used in this project. We have made extensive measurements to determine lattice parameter uniformity of several regions of this new material using the NIST lattice comparator. Measurements from this comparator have been shown to have a relative internal consistency near 1 x 10(-8). In the course of these measurements we noted a significant dependence of lattice parameter values on surface preparation of the samples. Samples prepared by grinding followed by chemical-mechanical (c-m) polishing show a wider distribution than samples prepared by grinding followed by etching. Surface preparation procedures mere altered to include etching after c-m polishing. This unexpected dependence on surface preparation raises the possibility that some of the NIST lattice comparison results presented at CPEM96 may be biased by surface preparation effects. To test this possibility, some of the samples included in our CPEM96 contribution have been etched and remeasured. Preliminary estimates of corrections to some NIST CPEM96 lattice comparison results appear to confirm that bias. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Kessler, EG (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 3 TC 14 Z9 14 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 221 EP 224 DI 10.1109/19.769568 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600020 ER PT J AU Deslattes, RD Kessler, EG AF Deslattes, RD Kessler, EG TI The molar volume of silicon: Discrepancies and limitations SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE Avogadro's number; silicon kilogram; X-ray diffraction; X-ray topography ID AVOGADRO CONSTANT AB We offer a new representation of the silicon molar volume discrepancy by attending to a previously incorrect accounting of the early work at the National Bureau of Standards (NBS), Removal of a poorly documented correction to the MBS density scale leads to a plausibly correct description of the molar volume anomaly problem. The possibility of discrepant metrology has been previously ruled out by sample exchanges, This led to several materials characterization exercises that gave important null results as briefly summarized here. We report the first nonnull results and examine their correlation with those samples with discrepant molar volume values. In the end, there is a reasonably optimistic prospect that concordant and accurate density values can emerge at an interesting level of significance (less than 10(-7)). A brief discussion of intrinsic limitations of melt-grown crystals is included. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Deslattes, RD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 9 TC 8 Z9 8 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 238 EP 241 DI 10.1109/19.769572 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600024 ER PT J AU Kupferman, SL Hamilton, CA AF Kupferman, SL Hamilton, CA TI Deployment of a compact, transportable, fully automated Josephson voltage standard SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE DC; Josephson; standard; transportable; voltage AB A compact, transportable, Josephson voltage standard, first reported at CPEM96, has now been field tested and has had ten months of use as a primary standard by National Aeronautics and Space Administration (NASA) laboratories. We discuss here its uncertainty assessment, the results of intercomparisons with conventional Josephson standards, operator training, and the experience of users. A second similar standard with an improved microwave system has been fabricated at the National Institute of Standards and Technology (NIST) and delivered to Sandia National Laboratories (SNL) for use by Department of Energy (DOE) standards laboratories. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Kupferman, SL (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. NR 9 TC 9 Z9 9 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 1999 VL 48 IS 2 BP 249 EP 252 DI 10.1109/19.769575 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600027 ER PT J AU Tang, YH Steiner, R Sims, J AF Tang, YH Steiner, R Sims, J TI Comparison of two Josephson array voltage standard systems using a set of Zener references SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE electric variables measurement; Josephson arrays; Josephson device measurements; low thermal emf; switches; voltage measurement; voltage reference; Zener diode AB It is possible to compare Josephson-array voltage systems to parts in 10(9) via multi-Zener reference interchanges and ultra-lo cv thermal-emf sw itching. These techniques were used to achieve a Type A uncertainty of 6 nV/V (k = 2) at the 1.018 V level, and to establish that the agreement between the two systems fell within the estimated 4 nV/V Type B relative uncertainty (k = 2). The method is useful in checking system operation under normal measurement configurations and programmed control. Data also indicated that thermal-emfs greater than 25 nV have fluctuations that are not perfectly canceled by either of the two differing measurement algorithms. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Tang, YH (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 262 EP 265 DI 10.1109/19.769578 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600030 ER PT J AU Benz, SP Hamilton, CA Burroughs, CJ Harvey, TE AF Benz, SP Hamilton, CA Burroughs, CJ Harvey, TE TI AC and DC bipolar voltage source using quantized pulses SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE digital-analog conversion; Josephson arrays; microwave integrated circuits; modulation; pulse circuits; signal synthesis; standards ID STANDARD; JUNCTIONS; CONVERTER; PROGRESS AB We have developed an accurate bipolar voltage source for ac and de metroloy, based on the quantized pulses of Josephson junctions. The output voltage is a factor of 4-6 higher than the amplitude of previous unipolar waveforms; this is achieved by generating bipolar waveforms where arrays of junctions are driven with both a broadband two-level digital code and a sinusoidal frequency, We experimentally demonstrate two bipolar waveforms: a 5 kHz sine wave with +/- 18 mV peak amplitude and quantization noise power eight orders of magnitude below the power in the fundamental frequency, and a 3.5 kHz square wave with +/- 13 mV peak amplitude and even harmonics at -100 dB (carrier). C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Benz, SP (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 10 TC 35 Z9 35 U1 1 U2 2 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 1999 VL 48 IS 2 BP 266 EP 269 DI 10.1109/19.769579 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600031 ER PT J AU Burroughs, CJ Benz, SP Hamilton, CA Harvey, TE AF Burroughs, CJ Benz, SP Hamilton, CA Harvey, TE TI Programmable 1 V DC voltage standard SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE Josephson junctions; Josephson voltage standard; voltage measurement ID PROGRESS AB We have developed a Josephson voltage standard that produces intrinsically stable voltages that are programmable from -1.1 to +1.1 V, The standard uses a binary array sequence of 32768 SNS (superconductor-normal-superconductor) Josephson junctions. The output can source or sink up to 2 mA and thus has high noise immunity. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Burroughs, CJ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 24 Z9 24 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 1999 VL 48 IS 2 BP 279 EP 281 DI 10.1109/19.769582 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600034 ER PT J AU Burroughs, CJ Benz, SP Hamilton, CA Harvey, TE Kinard, JR Lipe, TE Sasaki, H AF Burroughs, CJ Benz, SP Hamilton, CA Harvey, TE Kinard, JR Lipe, TE Sasaki, H TI Thermoelectric transfer difference of thermal converters measured with a Josephson source SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE digital-to-analog converter; Josephson array; metrology; standard; voltage ID VOLTAGE STANDARD AB We have measured the thermoelectric transfer difference of two thermal voltage converters using a Josephson source and compared the results to similar measurements made with a conventional semiconductor source, Both sources use the fast reversed de method. The Josephson source is an array of 16384 superconductor-normal-superconductor Josephson junctions that is rapidly switched between voltage states of +0.5, 0, and -0.5 V, A marginally significant difference is detected between measurements with the two different sources. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Electrotech Lab, Tsukuba, Ibaraki 3050045, Japan. RP Burroughs, CJ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 4 TC 32 Z9 33 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 282 EP 284 DI 10.1109/19.769583 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600035 ER PT J AU Lee, KC AF Lee, KC TI Dependence of contact resistance on current for ohmic contacts to quantized Hall resistors SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE breakdown; contact degradation; contact resistance; corrosion; current dependence; electrically active defects; ohmic contacts; quantized Hall resistor; quantum Hall effect ID BREAKDOWN; REGIME AB The dependence of contact resistance on current has been measured for a large number of ohmic contacts to quantized Hall resistors under quantum Hall effect conditions. Five different functional forms of current dependence are observed at low currents. The trend from best to worst quality can be correlated with the density of defects in the contact, regardless of the physical cause of the defects. The consequences of different types of contact resistance current dependence on the metrological use of samples are discussed. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Lee, KC (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 11 TC 3 Z9 3 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 319 EP 323 DI 10.1109/19.769592 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600044 ER PT J AU Jarrett, DG AF Jarrett, DG TI Evaluation of guarded high-resistance Hamon transfer standards SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE bridge circuits; insulation; measurement standards; resistance measurement; resistors; transfer standards AB An improved design for a guarded transfer standard in the resistance range 1 M Omega to 100 G Omega is described. Existing transfer standards and their limitations are reviewed along Kith a description of guard circuit theory. Measurements made to evaluate the effectiveness of guard networks are described and results are reported that verify the guard circuit behavior, Guarded transfer standards have been tested Kith internal and external guard networks showing the benefits of guarding transfer standards for high-resistance measurements. Interchangeable guard networks are used in the improved transfer standards to ensure complete guarding during all phases of the measurement process thus reducing errors caused by leakages to ground. These improved transfer standards ha re been developed to support National Institute of Standards and Technology (NIST) calibration services over the range 10 M Omega to 1 T Omega and to support extension of the calibration service to 10 TR and 100 To. C1 US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Elect Div,Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Jarrett, DG (reprint author), US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Elect Div,Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 4 TC 19 Z9 19 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 1999 VL 48 IS 2 BP 324 EP 328 DI 10.1109/19.769593 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600045 ER PT J AU Dziuba, RF Jarrett, DG Scott, LL Secula, AJ AF Dziuba, RF Jarrett, DG Scott, LL Secula, AJ TI Fabrication of high-value standard resistors SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE film-type resistors; resistance; resistance measurements; resistors; standards; wirewound resistors AB The National Institute of Standards and Technology (NIST) has fabricated stable, transportable 10 M Omega and 1 G Omega standard resistors for use in an international comparison of high resistances. This fabrication process is being applied to the construction of standard resistors of values up to 10 T Omega, with initial results indicating significant improvements in stability and fewer adverse effects induced by mechanical shock and vibration. C1 US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Elect Div,Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Dziuba, RF (reprint author), US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Elect Div,Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 7 TC 16 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 1999 VL 48 IS 2 BP 333 EP 337 DI 10.1109/19.769595 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600047 ER PT J AU Jeffery, AM Lee, LH Shields, JQ AF Jeffery, AM Lee, LH Shields, JQ TI Model tests to investigate the effects of geometrical imperfections on the NIST calculable capacitor SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE calculable capacitor; capacitance measurements ID REALIZATION; OHM AB The calculable capacitor at National Institute of Standards and Technology (MST) links the U.S. capacitance unit to the SI unit and has a relative standard uncertainty of 2 x 10(-8) Geometrical imperfections are one of the largest sources of this uncertainty. Tests with a model calculable capacitor have been done to better evaluate and reduce this uncertainty. These included evaluations of the Effect of eccentricity of the blocking electrodes used to define the capacitor's length and of uniform taper on all the calculable capacitor bars. In addition, the effect of tilt of the blocking electrode and taper in three or fewer bars was investigated. A new cone-shape for the tip of the blocking electrode was also studied. C1 US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Elect Div,Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Jeffery, AM (reprint author), US Dept Commerce, Technol Adm, Natl Inst Stand & Technol, Elect Div,Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 6 TC 12 Z9 12 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 356 EP 359 DI 10.1109/19.769600 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600052 ER PT J AU Elmquist, RE AF Elmquist, RE TI Cryogenic current comparator measurements at 77 K using thallium-2223 thick-film shields SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE cryogenic current comparators; high temperature; superconductors; resistance measurement; superconducting shielding ID NOISE AB Several different magnetic shield geometries were used to study cryogenic current comparator (CCC) operation with thallium-based thick film superconducting shields at 77 K. These shields are found to have good magnetic shielding properties and to support low-level persistent currents. This study investigates geometric properties of the magnetic coupling between the CCC and one type of superconducting quantum interference device (SQUID) sensor. The sensitivity of the SQUID and its coupling to the shielding currents limit ten-to-one CCC resistance ratio measurements to approximately 0.2 mu Omega/Omega in relative uncertainty. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Elmquist, RE (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 7 TC 4 Z9 4 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 383 EP 386 DI 10.1109/19.769606 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600058 ER PT J AU Petersons, O Nelson, TL Oldham, NM FitzPatrick, GJ AF Petersons, O Nelson, TL Oldham, NM FitzPatrick, GJ TI Extension of voltage range for power and energy calibrations SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE active voltage divider; calibration; power measurement; precision AB A special purpose ac voltage divider system with ratios of 600, 480, 360, 277, and 240 V to 120 V has been developed to extend the range of primary electric power calibrations from 120-600 V at 50 and 60 Hz, The developmental goal has been to realize ac voltage scaling within 5 mu V/V overall relative uncertainty. By employing a technique consisting of a special two-stage resistive divider compensated with an active circuit, the overall uncertainty achieved after calibration is 4 mu V/V. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Petersons, O (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 3 TC 5 Z9 5 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 439 EP 443 DI 10.1109/19.769620 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600072 ER PT J AU Simmon, ED FitzPatrick, GJ Petersons, O AF Simmon, ED FitzPatrick, GJ Petersons, O TI Calibration of dissipation factor standards SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE calibration; capacitance bridge; capacitor loss; measurements; dissipation factor standards; high voltage; loss angle; phase angle; tan delta; transformer loss measurements AB Working standards for dissipation factor (D) obtained by connecting a shielded three-terminal capacitor in series with a shielded precision resistor have been developed for calibration purposes. Precision conductance boxes have been built for use with a single three-terminal 1000 pF gas capacitor standard to create dissipation factor standards having values from 2 x 10(-5) to 1 x 10(-2). The design and testing of these D standards, including precautions in their construction and use, is presented. Calibration procedures using the NIST high voltage capacitance bridge and the measurement uncertainties are discussed. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Simmon, ED (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 6 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 450 EP 452 DI 10.1109/19.769624 PG 3 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600075 ER PT J AU Hong, FL Ishikawa, J Yoda, J Ye, J Ma, LS Hall, JL AF Hong, FL Ishikawa, J Yoda, J Ye, J Ma, LS Hall, JL TI Frequency comparison of I-127(2)-stabilized Nd : YAG lasers SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE frequency control; frequency stability; laser stability; neodynium : YAG lasers; spectroscopy; standards ID ABSOLUTE FREQUENCY; MOLECULAR-IODINE; 532 NM; TRANSITIONS AB A first international comparison of I-2-stabilized Nd:YAG lasers has been made between the National Research Laboratory of Metrology (NRLM), Tsukuba, Japan, the Joint Institute for Laboratory Astrophysics JILA (formerly the Joint Institute for Laboratory Astrophysics), Boulder, CO, the National Institute of Standards and Technology (NIST), Boulder, and the University of Colorado, Boulder. The results of the comparison show that the square root Allan variance of the portable NRLM laser has reached 2 x 10(-14) when the integration time is larger than 300 s, Matrix measurements were made for five hyperfine components from a(6) to a(10) of the R(56)32-0 line. The averaged frequency difference between the NRLM and JILA lasers for four measurements made on three separate days was -4996 Hz (NRLM-JILA, at 532 nm) with a standard deviation of 88 Hz. C1 Natl Res Lab Metrol, Ibaraki, Osaka 3058536, Japan. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP Hong, FL (reprint author), Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Ye, Jun/C-3312-2011; Hong, Feng-Lei/N-3098-2014 OI Hong, Feng-Lei/0000-0003-1318-2635 NR 10 TC 33 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD APR PY 1999 VL 48 IS 2 BP 532 EP 536 DI 10.1109/19.769651 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600095 ER PT J AU Ye, J Robertsson, L Picard, S Ma, LS Hall, JL AF Ye, J Robertsson, L Picard, S Ma, LS Hall, JL TI Absolute frequency atlas of molecular I-2 lines at 532 nm SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE frequency control; frequency measurement; frequency modulation; laser spectroscopy; laser stability; measurement standards; YAG lasers ID HYPERFINE-STRUCTURE; TRANSITION; STATE AB With the aid of two iodine spectrometers, we report for the first time the measurement of the hyperfine splittings of the P(54) 32-0 and R(57) 32-0 transitions near 532 nm, Within the tuning range of the frequency-doubled Nd:YAG laser, modulation transfer spectroscopy recovers nine relatively strong ro-vibrational transitions of I-127(2) molecules with excellent SNR, These transitions are now linked together with their absolute frequencies determined by measuring directly the frequency gaps between each line and the R(56) 32-0: a(10) component. This provides an attractive frequency reference network in this wavelength region. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80302 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Ye, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Ye, Jun/C-3312-2011 NR 13 TC 96 Z9 101 U1 1 U2 9 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 1999 VL 48 IS 2 BP 544 EP 549 DI 10.1109/19.769654 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600098 ER PT J AU Hall, JL Ma, LS Taubman, M Tiemann, B Hong, FL Pfister, O Ye, J AF Hall, JL Ma, LS Taubman, M Tiemann, B Hong, FL Pfister, O Ye, J TI Stabilization and frequency measurement of the I-2-stabilized Nd : YAG laser SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE laser stabilization; modulation transfer; Nd : YAG laser; optical frequency measurement ID ABSOLUTE FREQUENCY; MOLECULAR-IODINE; COMB GENERATOR; 532 NM; SPECTROSCOPY; TRANSITIONS; CAVITY AB We report improved stabilization results for and progress toward a more accurate frequency measurement of the 532 nm iodine-stabilized system based on a frequency-doubled Nd:YAG ring laser. We confirm the CCL-adopted frequency well within its stated uncertainty (+/-40 kHz). C1 Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO 80309 USA. E China Normal Univ, Quantum Opt Lab, Shanghai 200062, Peoples R China. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Duke Univ, Dept Phys, Durham, NC 27708 USA. Calif Polytech Univ, Quantum Opt Grp, Pasadena, CA 91125 USA. RP Hall, JL (reprint author), Natl Inst Stand & Technol, Quantum Phys Div, 325 Broadway, Boulder, CO 80309 USA. RI Ye, Jun/C-3312-2011; Pfister, Olivier/A-4924-2013; Hong, Feng-Lei/N-3098-2014 OI Pfister, Olivier/0000-0003-3386-9661; Hong, Feng-Lei/0000-0003-1318-2635 NR 15 TC 102 Z9 106 U1 2 U2 28 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 1999 VL 48 IS 2 BP 583 EP 586 DI 10.1109/19.769663 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600107 ER PT J AU Vogel, KR Dinneen, TP Gallagher, A Hall, JL AF Vogel, KR Dinneen, TP Gallagher, A Hall, JL TI Narrow-line Doppler cooling of strontium to the recoil limit SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article; Proceedings Paper CT 1998 Conference on Precision Electromagnetic Measurements (CPEM 98) CY JUL 06-10, 1998 CL WASHINGTON, D.C. SP Natl Inst Stand & Technol, Bur Int Poids & Mesures, IEEE, Instrumentat & Measurement Soc, Natl Res Council Canada, Union Radio Sci Int, Amer Assoc Lab Accreditat, Andeen Hagerling Inc, APS, Instrument & Measurement Sci Top Grp, APS, Precis Measurement & Fundamental Constants, Baltimore Gas & Elect, Cal Lab Magazine, Clarke Hess Commun Res Corp, Creat Mkt Assoc, Fluke Corp, Guildline Instruments, Hewlett Packard Co, Instrument Support Solut Div, IEEE, Instrument & Measurement Soc, Washington Chapter, IEEE, Natl Capital Area Council, Natl Conf Stand Lab, Org Amer States, Wavetek Corp DE alkaline earths; frequency metrology; laser cooling; laser trapping; strontium ID ATOMIC-BEAM; LASER; SPECTROSCOPY; FREQUENCY; CALCIUM; PHASE AB Experimental results on narrow line cooling of strontium atoms are presented. Doppler cooling is performed on the S-1(0)-P-3(1) intercombination transition at 689 nm resulting in temperatures near the recoil limit in a one dimensional (1-D) optical molasses. Frequency chirp cooling is successfully demonstrated as a means of expanding the cooling range. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO 80309 USA. RP Vogel, KR (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 19 TC 30 Z9 31 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 1999 VL 48 IS 2 BP 618 EP 621 DI 10.1109/19.769671 PG 4 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 206GU UT WOS:000080869600115 ER PT J AU Williams, DF Rogers, JE Holloway, CL AF Williams, DF Rogers, JE Holloway, CL TI Multiconductor transmission-line characterization: Representations, approximations, and accuracy SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE measurement; modal cross power; multiconductor transmission line ID WAVE-GUIDE STRUCTURES; CIRCUIT MODEL; LOSSES AB This paper investigates a measurement method that characterizes lossy printed multiconductor transmission lines, its accuracy, the choice of measurement representations, and some simple approximations. We illustrate the method with measurements of a pair of lossy coupled asymmetric microstrip lines. C1 US Dept Commerce, Natl Inst Stand & Technol, Boulder Labs, Boulder, CO 80303 USA. US Dept Commerce, Inst Telecommun Sci, Boulder Labs, Boulder, CO 80303 USA. RP Williams, DF (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Boulder Labs, Boulder, CO 80303 USA. NR 25 TC 19 Z9 19 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD APR PY 1999 VL 47 IS 4 BP 403 EP 409 DI 10.1109/22.754872 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 184ZE UT WOS:000079643000004 ER PT J AU Phillips, PJ Bowyer, KW AF Phillips, PJ Bowyer, KW TI Introduction to the special section on empirical evaluation of computer vision algorithms SO IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE LA English DT Editorial Material C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ S Florida, Dept Comp Sci & Engn, Tampa, FL 33620 USA. RP Phillips, PJ (reprint author), Natl Inst Stand & Technol, Bldg 225,Room A216,100 Bur Dr,Stop 8490, Gaithersburg, MD 20899 USA. NR 0 TC 10 Z9 10 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0162-8828 J9 IEEE T PATTERN ANAL JI IEEE Trans. Pattern Anal. Mach. Intell. PD APR PY 1999 VL 21 IS 4 BP 289 EP 290 DI 10.1109/TPAMI.1999.761260 PG 2 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 187HL UT WOS:000079781200001 ER PT J AU Stone, W Reed, K Chang, P Pfeffer, L Jacoff, A AF Stone, W Reed, K Chang, P Pfeffer, L Jacoff, A TI NIST research toward construction site integration and automation SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article AB Current uses of computers in construction include design, planning, scheduling, and cost estimating. Much more could be achieved on a fully computer-integrated construction site. This paper describes initial work at the National Institute of Standards and Technology toward construction site integration and automation, beginning with a simple steel-erection procedure using an instrumented crane. CAD-generated geometry sets are transformed into a library of 3D construction site objects. These objects are then loaded into an augmented simulation system that tracks both equipment and resources based on real-time data from the construction site. With some future enhancements, the end result will be a world model of the site, in which as-built conditions can be assessed, current construction processes can be viewed as they occur, planned sequences of processes can be tested, and object information can be retrieved on demand. A project can be viewed and managed remotely using this tool. Remotely controlled construction in hazardous environments is a natural extension of this environment. The National Construction Automation Testbed (NCAT) is currently being used in various research projects with the intentions of making such possibilities a reality. A major effort in the NCAT is the development and testing of the metrology, communication, and simulation protocols required. C1 Natl Inst Stand & Technol, Constr Metrol & Automat Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Integrated Constr Grp, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Mfg Engn Lab, Gaithersburg, MD 20899 USA. RP Stone, W (reprint author), Natl Inst Stand & Technol, Constr Metrol & Automat Grp, Gaithersburg, MD 20899 USA. NR 5 TC 5 Z9 5 U1 0 U2 0 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD APR PY 1999 VL 12 IS 2 BP 50 EP 57 DI 10.1061/(ASCE)0893-1321(1999)12:2(50) PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 178RG UT WOS:000079279500004 ER PT J AU Yu, LL Turk, GC Koirtyohann, SR AF Yu, LL Turk, GC Koirtyohann, SR TI Characterization of a hydrogen flame as an ion source form mass spectrometry SO JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY LA English DT Article ID PLASMA; INTERFERENCES; IONIZATION; REDUCTION; POTASSIUM; OXIDE AB A commercial inductively coupled plasma (ICP) mass spectrometer was modified to employ an air-hydrogen flame in place of the ICP as an ion source. A liquid nitrogen trap was placed in the vacuum line to remove water. A very simple intrinsic mass spectral background was obtained with the hydrogen flame ionization mass spectrometry (FIMS). Molecular ions such as K(H2O)(+), Na(H2O)( +), Ca(H2O)(+) and CaOH(H2O)(x)(+) (x = 0-2) were observed when solutions containing Na, K or Ca were aspirated, Although the presence of the molecular ions complicated the mass spectra, it also provided a wider choice of analytical masses for an analyte. Isotope ratio measurements of Ca were made with both Ca+ and CaOH+ species at masses 40, 44, 57 and 61. Better isotope ratio precision was obtained at CaOH+ masses relative to there for Ca+ because the sensitivity was about 10 times higher. Isotope ratio measurement of K wats made at masses 39 and 41. A ratio precision of about 0.2 and 0.5% was obtained for K and Ca, respectively. The results suggest that the FIMS is suitable for the isotope ratio measurement of K and Ca in simple matrices, and that the air-hydrogen flame is a more desirable ion source than an air-acetylene flame for FIMS. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Yu, LL (reprint author), NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 27 TC 4 Z9 4 U1 1 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0267-9477 J9 J ANAL ATOM SPECTROM JI J. Anal. At. Spectrom. PD APR PY 1999 VL 14 IS 4 BP 669 EP 674 DI 10.1039/a809797f PG 6 WC Chemistry, Analytical; Spectroscopy SC Chemistry; Spectroscopy GA 188GY UT WOS:000079839500025 ER PT J AU Crawford, TM Duchon, CE AF Crawford, TM Duchon, CE TI An improved parameterization for estimating effective atmospheric emissivity for use in calculating daytime downwelling longwave radiation SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WAVE-RADIATION; CLEAR SKIES; CLOUD AB An improved parameterization is presented for estimating effective atmospheric emissivity for use in calculating downwelling longwave radiation based on temperature, humidity, pressure, and solar radiation observations. The first improvement is the incorporation of an annual sinusoidal variation in effective clear-sky atmospheric emissivity, based on typical climatological variations in near-surface vapor pressure. The second is the continuous estimation of fractional cloudiness by taking the ratio of observed solar radiation to a modeled clear-sky solar radiation. Previous methods employed observer-estimated fractional cloudiness. Data from the Atmospheric Radiation Measurement (ARM) program were used to develop these improvements. The estimation of cloudiness was then used to modify the effective clear-sky atmospheric emissivity in order to calculate 30-min averages of downwelling longwave radiation. Monthly mean bias errors (mbe's) of -9 to +4 W m(-2) and root-mean-square errors (rmse's) of 11-22 W m(-2) were calculated based on ARM data over a 1-yr period. These mbe's were smaller overall than any of the six previous methods tested, while the rmse's were similar to the best previous methods. The improved parameterization was then tested on FIFE data from the summer of 1987. Although the monthly mbe's were larger, the rmse's were smaller. It is also shown that data from upper-air soundings can be used to calculate the effective atmospheric emissivity rather than specifying the aforementioned sinusoidal variation. Using ARM upper-air soundings, this method resulted in larger mbe's, -7 to +11 W m(-2), especially during the summer months, and similar rmse's. The success of the method suggests that it has application at any observing site within reasonable proximity of an upper-air sounding, while removing the empiricism used to specify the annual sinusoidal variation in emissivity. C1 Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. RP Crawford, TM (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 21 TC 152 Z9 160 U1 2 U2 20 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 APR PY 1999 VL 38 IS 4 BP 474 EP 480 DI 10.1175/1520-0450(1999)038<0474:AIPFEE>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 186VX UT WOS:000079752300008 ER PT J AU Suwito, W Dunn, ML Cunningham, SJ Read, DT AF Suwito, W Dunn, ML Cunningham, SJ Read, DT TI Elastic moduli, strength, and fracture initiation at sharp notches in etched single crystal silicon microstructures SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID BONDED DISSIMILAR MATERIALS; INTENSITY FACTOR PREDICTION; THIN-FILMS; INTERFACE CORNER; STRESS SINGULARITIES; TENSILE-STRENGTH; ANISOTROPIC COMPOSITES; 2-MATERIAL WEDGE; YOUNGS MODULUS; CRITERION AB We designed and fabricated a series of micromechanical test structures for microtensile testing by anisotropically etching epitaxial silicon. Specimens were fabricated to study Young's moduli, the uniaxial tensile strength, and the strength of T-structures which are tensile bars with an abrupt reduced cross section that have a 90 degrees corner at the point of reduction. They are a generic mimic of actual transitions that occur in micromechanical structures due to anisotropic etching. The test structures were loaded in uniaxial tension in a piezoactuated microtensile test apparatus. The applied force and crosshead displacement were recorded and displacements in the specimen gage section were directly measured using a speckle interferometry technique. During tensile loading of the T-structures, fracture always initiates at the sharp 90 degrees corners. This results in an interesting apparent strength scaling where the nominal strength of the structures increases as their width decreases. In order to understand the fracture initiation from the sharp 90 degrees corners of the silicon T-structures, we carried out a complete analysis of the elastic fields at the 90 degrees corners by coupling an asymptotic analysis (to compute the asymptotic radial and angular dependence of the elastic fields up to an arbitrary constant for each loading mode, the stress intensity), and full-field finite element calculations (to determine the magnitude of the stress intensities for specific geometries and loadings). Excellent results are obtained by using a single parameter, the critical mode I stress intensity, to correlate fracture initiation from the sharp 90 degrees corners of the T-structures. (C) 1999 American Institute of Physics. [S0021-8979(99)00306-0]. C1 Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. Ford Microelect Inc, Colorado Springs, CO 80921 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Suwito, W (reprint author), Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. EM dunnm@spot.colorado.edu OI DUNN, MARTIN/0000-0002-4531-9176 NR 83 TC 56 Z9 56 U1 5 U2 13 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD APR 1 PY 1999 VL 85 IS 7 BP 3519 EP 3534 DI 10.1063/1.369711 PG 16 WC Physics, Applied SC Physics GA 180UQ UT WOS:000079403900019 ER PT J AU Klein, SA Soden, BJ Lau, NC AF Klein, SA Soden, BJ Lau, NC TI Remote sea surface temperature variations during ENSO: Evidence for a tropical atmospheric bridge SO JOURNAL OF CLIMATE LA English DT Article ID ASIAN SUMMER MONSOON; SOUTHERN-OSCILLATION; INTERANNUAL VARIABILITY; SEASONAL-VARIATION; SST ANOMALIES; WIND STRESS; OCEAN; PACIFIC; CIRCULATION; SCALE AB In an El Nino event, positive SST anomalies usually appear in remote ocean basins such as the South China Sea, the Indian Ocean, and the tropical North Atlantic approximately 3 to 6 months after SST anomalies peak in the tropical Pacific. Ship data from 1952 to 1992 and satellite data from the 1980s both demonstrate that changes in atmospheric circulation accompanying El Nino induce changes in cloud cover and evaporation which, in turn, increase the net heat flux entering these remote oceans. It is postulated that this increased heat flux is responsible for the surface warming of these oceans. Specifically, over the eastern Indian Ocean and South China Sea, enhanced subsidence during El Nino reduces cloud cover and increases the solar radiation absorbed by the ocean, thereby leading to enhanced SSTs. In the tropical North Atlantic, a weakening of the trade winds during El Nino reduces surface evaporation and increases SSTs. These relationships fit the concept of an "atmospheric bridge" that connects SST anomalies in the central equatorial Pacific to those in remote tropical oceans. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ USA. RP Klein, SA (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. RI Klein, Stephen/H-4337-2016 OI Klein, Stephen/0000-0002-5476-858X NR 48 TC 616 Z9 680 U1 11 U2 73 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 PY 1999 VL 12 IS 4 BP 917 EP 932 DI 10.1175/1520-0442(1999)012<0917:RSSTVD>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 182LJ UT WOS:000079500200001 ER PT J AU Coriell, SR McFadden, GB Sekerka, RF AF Coriell, SR McFadden, GB Sekerka, RF TI Selection mechanisms for multiple similarity solutions for solidification and melting SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE alloy solidification; alloy melting; multiple solutions; similarity solutions; interface kinetics ID DIFFUSION COUPLES; SURFACE-TENSION; CRYSTAL-GROWTH; STEFAN PROBLEM; INSTABILITY; INTERFACE; STABILITY; TERNARY; PLANAR; ALLOY AB When a solid phase of uniform temperature T-S infinity and composition C-S infinity is brought into contact with a liquid phase of uniform temperature T-L infinity and composition C-L infinity there exist (under the assumption of local equilibrium at the solid-liquid interface) similarity solutions for which the position X of the interface is proportional to the square root of time t, i.e., X = lambda root t. Recently, we explored situations in which there are multiple similarity solutions, e.g., three values of lambda, for the same far-field and initial conditions. We examine the stability of these similarity solutions with respect to perturbations which preserve the planar geometry. When there are three similarity solutions, we find that the solution corresponding to the intermediate value of lambda, is unstable and the other two solutions are stable. We then relax the assumption of local equilibrium by assuming a linear kinetic law in which the interface velocity is proportional to the deviation of interface temperature from the equilibrium temperature. We use an expansion technique, valid at small. times, which leads to a single solution with a finite initial velocity. Time-dependent numerical calculations of the complete set of governing equations are used to follow the transition from kinetic control to a similarity solution. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Carnegie Mellon Univ, Dept Math & Phys, Pittsburgh, PA 15213 USA. RP Coriell, SR (reprint author), Natl Inst Stand & Technol, A 153 Mat, Gaithersburg, MD 20899 USA. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 26 TC 11 Z9 13 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 APR PY 1999 VL 200 IS 1-2 BP 276 EP 286 DI 10.1016/S0022-0248(98)01303-7 PG 11 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 188HK UT WOS:000079840600037 ER PT J AU Boettinger, WJ Warren, JA AF Boettinger, WJ Warren, JA TI Simulation of the cell to plane front transition during directional solidification at high velocity SO JOURNAL OF CRYSTAL GROWTH LA English DT Article ID PHASE-FIELD MODEL; ALLOYS AB Using the alloy phase-field method with a frozen temperature approximation, interface morphology and solute segregation patterns during directional solidification are examined near the high velocity (absolute stability) condition for planar growth. The dynamics of the breakdown of initially planar interfaces into cellular structures are shown. At sufficiently high solidification speed, a planar interface is reestablished after breakdown during the initial transient. The cell spacings, depths, tip temperatures, tip radii, and concentration patterns are determined as a function of solidification velocity. The presence of solute trapping is manifest in the variation of the degree of solute partitioning across the interfacial region with interface speed. Published by Elsevier Science B.V. C1 NIST, Mat Sci & Engn Lab, Div Met, Gaithersburg, MD 20899 USA. RP Warren, JA (reprint author), NIST, Mat Sci & Engn Lab, Div Met, Bldg 223-B164, Gaithersburg, MD 20899 USA. RI Warren, James/B-1698-2008 OI Warren, James/0000-0001-6887-1206 NR 10 TC 84 Z9 92 U1 0 U2 11 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 1999 VL 200 IS 3-4 BP 583 EP 591 DI 10.1016/S0022-0248(98)01063-X PG 9 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 188QN UT WOS:000079859800034 ER PT J AU Jung, YG Wuttiphan, S Peterson, IM Lawn, BR AF Jung, YG Wuttiphan, S Peterson, IM Lawn, BR TI Damage modes in dental layer structures SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE dental ceramics; fracture; Hertzian contact; layers; teeth ID HERTZIAN CONTACT DAMAGE; STRESS-STRAIN CURVES; MECHANICAL CHARACTERIZATION; STRENGTH DEGRADATION; FRACTURE-TOUGHNESS; CYCLIC FATIGUE; GLASS-CERAMICS; ALUMINA; COATINGS; MICROSTRUCTURE AB Natural teeth (enamel/dentin) and most restorations are essentially layered structures. This study examines the hypothesis that coating thickness and coating/substrate mismatch are key factors in the determination of contact-induced damage in clinically relevant bilayer composites. Accordingly, we study crack patterns in two model "coating/substrate" bilayer systems conceived to simulate crown and tooth structures, at opposite extremes of elastic/plastic mismatch: porcelain on glass-infiltrated alumina ("soft/hard"); and glass-ceramic on resin composite ("hard/soft). Hertzian contacts are used to investigate the evolution of fracture damage in the coating layers, as functions of contact load and coating thickness. The crack patterns differ radically in the two bilayer systems: In the porcelain coatings, cone cracks initiate at the coating top surface; in the glass-ceramic coatings, cone cracks again initiate at the top surface, but additional, upward-extending transverse cracks initiate at the internal coating/substrate interface, with the latter dominant. The substrate is thereby shown to have a profound influence on the damage evolution to ultimate failure in the bilayer systems. However, the cracks are highly stabilized in both systems, with wide ranges between the loads to initiate first cracking and to cause final failure, implying damage-tolerant structures. Finite element modeling is used to evaluate the tensile stresses responsible for the different crack types. The clinical relevance of these observations is considered. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Lawn, BR (reprint author), NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [P01 DE10976] NR 53 TC 85 Z9 88 U1 0 U2 10 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD APR PY 1999 VL 78 IS 4 BP 887 EP 897 PG 11 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 186ZN UT WOS:000079761600009 PM 10326733 ER PT J AU Zbib, HM Hirth, JP Khraishi, T Thomson, R AF Zbib, HM Hirth, JP Khraishi, T Thomson, R TI Prolegomena SO JOURNAL OF ENGINEERING MATERIALS AND TECHNOLOGY-TRANSACTIONS OF THE ASME LA English DT Editorial Material C1 Washington State Univ, Pullman, WA 99164 USA. NIST, Gaithersburg, MD 20899 USA. RP Zbib, HM (reprint author), Washington State Univ, Pullman, WA 99164 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0094-4289 J9 J ENG MATER-T ASME JI J. Eng. Mater. Technol.-Trans. ASME PD APR PY 1999 VL 121 IS 2 BP 113 EP 113 DI 10.1115/1.2812353 PG 1 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 189JJ UT WOS:000079901100001 ER PT J AU Schultz, MK Biegalski, SR Inn, KGW Yu, L Burnett, WC Thomas, JLW Smith, GE AF Schultz, MK Biegalski, SR Inn, KGW Yu, L Burnett, WC Thomas, JLW Smith, GE TI Optimizing the removal of carbon phases in soils and sediments for sequential chemical extractions by coulometry SO JOURNAL OF ENVIRONMENTAL MONITORING LA English DT Article ID TRACE-METALS; FRACTIONATION; SPECIATION; PLUTONIUM; PARTICLES; ACTINIDE; MARINE; SYSTEM; MATTER; RIVER AB We have developed a coulometric technique to optimize the removal of the carbonate and organic fractions for sequential chemical extractions of soils and sediments. The coulometric system facilitates optimizing these two fractions by direct real-time measurement of carbon dioxide (CO2) evolved during the removal of these two fractions. Further analyses by ICP-MS and alpha-spectrometry aided in interpreting the results of coulometry experiments. The effects of time, temperature, ionic strength and pH were investigated. The sensitivity of the coulometric reaction vessel/detection system was sufficient even at very low total carbon content (<0.1 mol kg(-1)). The efficiency of the system is estimated to be 96% with a standard deviation of 8%. Experiments were carried out using NIST Standard Reference Materials 4357 Ocean Sediment (OS), 2704 Buffalo River Sediment (BRS), and pure calcium carbonate. Carbonate minerals were dissolved selectively using an ammonium acetate-acetic acid buffer. Organic matter was then oxidized to CO2 using hydrogen peroxide (H2O2) in nitric acid. The carbonate fraction was completely dissolved within 120 min under all conditions examined (literature suggests up to 8 h). For the OS standard, the oxidation of organic matter self-perpetuates between 45 and 50 degrees C, a factor of two less than commonly suggested, while organic carbon in the BRS standard required 80 degrees C for the reaction to proceed to completion. For complete oxidation of organic matter, we find that at least three additions of H2O2 are required (popular methods suggest one or two). C1 Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. Florida State Univ, Dept Oceanog, Tallahassee, FL 32306 USA. RP Schultz, MK (reprint author), Natl Inst Stand & Technol, Ionizing Radiat Div, Mail Stop 8462,100 Bur Dr, Gaithersburg, MD 20899 USA. RI Biegalski, Steven/A-7765-2010; Yu, Lee/N-7263-2015 OI Yu, Lee/0000-0002-8043-6853 NR 31 TC 15 Z9 15 U1 1 U2 9 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD,, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1464-0325 J9 J ENVIRON MONITOR JI J. Environ. Monit. PD APR PY 1999 VL 1 IS 2 BP 183 EP 190 DI 10.1039/a900534j PG 8 WC Chemistry, Analytical; Environmental Sciences SC Chemistry; Environmental Sciences & Ecology GA 255XR UT WOS:000083695900009 PM 11529098 ER PT J AU Klokocnik, J Wagner, CA Kostelecky, J AF Klokocnik, J Wagner, CA Kostelecky, J TI Spectral accuracy of Jgm3 from satellite crossover altimetry SO JOURNAL OF GEODESY LA English DT Article DE dynamics of artificial satellites; satellite altimetry; dual-satellite crossover altimetry; gravity-field models; accuracy assessments; reference systems; coordinate system offset ID LATITUDE-LUMPED COEFFICIENTS; GEOSAT; TOPEX/POSEIDON AB A detailed accuracy assessment of the geopotential model Jgm3 is made based on independent single- and dual-satellite sea-height differences at crossovers from altimetry with Jgm3-based orbits. These differences, averaged over long time spans and in latitude bands, are converted to spectra (latitude-lumped coefficients) by least-squares estimation. The observed error spectra so obtained are then compared directly to error projections for them from the Jgm3 variance-covariance matrix. It is found from these comparisons that Jgm3 is generally well calibrated with respect to the crossover altimetry of and between Geosat, TOPEX/Poseidon (T/P), and Ers 1. Some significant discrepancies at a few lower orders (namely m=1 and 3) indicate a need for further improvement of Jgm3. A companion calibration (by order) of the geopotential model Jgm2 shows its variance-covariance matrix also to be generally well calibrated for the same single- and dual-satellite altimeter data sets (but based on Jgm2 orbits), except that the error projections for Geosat are too pessimistic. The analysis of the dual-satellite crossovers reveals possible relative coordinate system offsets (particularly for Geosat with respect to T/P) which have been discussed previously. The long-term detailed seasonally averaged Geosat sea level with respect to T/P (covering 1985-1996) should be useful in gauging the relative change in sea level between different parts of the ocean over the single 4-year gap between these missions (1988-1992). C1 Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. NOAA, Silver Spring, MD 20910 USA. Res Inst Geodesy, CZ-25066 Zdiby, Czech Republic. RP Klokocnik, J (reprint author), Acad Sci Czech Republ, Inst Astron, CZ-25165 Ondrejov, Czech Republic. RI Klokocnik, Jaroslav/G-9025-2014 NR 24 TC 7 Z9 7 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-7714 J9 J GEODESY JI J. Geodesy PD APR PY 1999 VL 73 IS 3 BP 138 EP 146 DI 10.1007/s001900050229 PG 9 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 195TW UT WOS:000080269100005 ER PT J AU Campbell, WH AF Campbell, WH TI Comment on "Current understanding of magnetic storms: Storm-substorm relationships," by Y. Kamide et al. SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material C1 NOAA, Natl Geophys Data Ctr, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. RP Campbell, WH (reprint author), NOAA, Natl Geophys Data Ctr, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. NR 9 TC 5 Z9 5 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 APR 1 PY 1999 VL 104 IS A4 BP 7049 EP 7049 DI 10.1029/1999JA900019 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600034 ER PT J AU Kamide, Y Baumjohann, W Daglis, IA Gonzalez, WD Grande, M Joselyn, JA McPherron, RL Phillips, JL Reeves, EGD Rostoker, G Sharma, AS Singer, HJ Tsurutani, BT Vasyliunas, VM AF Kamide, Y Baumjohann, W Daglis, IA Gonzalez, WD Grande, M Joselyn, JA McPherron, RL Phillips, JL Reeves, EGD Rostoker, G Sharma, AS Singer, HJ Tsurutani, BT Vasyliunas, VM TI Comment on "Current understanding of magnetic storms: Storm-substorm relationships," by Y. Kamide et al. Reply SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Japan. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. Natl Observ Athens, Inst Ionospher & Space Res, Penteli, Greece. Inst Pesquisas Espaciais, Sao Paulo, Brazil. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. NOAA, Space Environm Ctr, Boulder, CO USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Alberta, Dept Phys, Edmonton, AB, Canada. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. RP Kamide, Y (reprint author), Nagoya Univ, Solar Terr Environm Lab, Toyokawa, Japan. EM kamide@stelab.nagoya-u.ac.jp; bj@mpe-garching.mpg.de; daglis@creator.space.noa.gr; gonzalez@dge.inpe.br; M.Grande@rl.ac.uk; jjoselyn@sec.noaa.gov; rmcpherron@igpp.ucla.edu; JLPhilli@ems.jsc.gov; reeves@lanl.gov; rostoker@space.ualberta.ca; ssh@avl.umd.edu; hsinger@sec.noaa.gov; btsurutani@jplsp.jpl.nasa.gov; vasyliunas@linaxl.mpae.gwdg.de RI Baumjohann, Wolfgang/A-1012-2010; Daglis, Ioannis/L-6100-2013; Reeves, Geoffrey/E-8101-2011; Grande, Manuel/C-2242-2013 OI Baumjohann, Wolfgang/0000-0001-6271-0110; Daglis, Ioannis/0000-0002-0764-3442; Reeves, Geoffrey/0000-0002-7985-8098; Grande, Manuel/0000-0002-2233-2618 NR 5 TC 1 Z9 1 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 APR 1 PY 1999 VL 104 IS A4 BP 7051 EP 7051 DI 10.1029/1999JA900020 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600035 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 Solar Terr Phys A, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr Solar Terr Phys A, 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 APR 1 PY 1999 VL 104 IS A4 BP 7053 EP 7054 DI 10.1029/1999JA900107 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 182CU UT WOS:000079481600036 ER PT J AU Johnson, D Smith, M Koren, V Finnerty, B AF Johnson, Dennis Smith, Michael Koren, Victor Finnerty, Bryce TI COMPARING MEAN AREAL PRECIPITATION ESTIMATES FROM NEXRAD AND RAIN GAUGE NETWORKS SO JOURNAL OF HYDROLOGIC ENGINEERING LA English DT Article AB Mean areal precipitation values (MAPX) derived from next generation weather radar (NEXRAD) stage III data are compared with mean areal precipitation (MAP) values derived from a precipitation gauge network. The gauge-derived MAPs are computed using Thiessen polygon weighting, whereas the radar-based MAPXs utilize the gridded stage III radar precipitation products that have been conditioned with gauge measurements and have been merged with overlapping radar fields. We compare over 4,000 pairs of MAPX and MAP estimates over a 3-year time period for each of eight basins in the southern plains region of the United States. Over the long term, mean areal estimates derived from NEXRAD generally are 5-10% below gauge-derived estimates. In the smallest basin, the long-term MAPX mean was greater than the MAP. For storm events, a slight tendency for NEXRAD to measure fewer yet more intense intervals of precipitation is identified. Comparison of hydrologic simulations using the two forcings indicates that significant differences in runoff volume can result. This work is aimed at providing insight into the use of a data product that is becoming increasingly available for public use. It also is aimed at investigating the use of radar data in hydrologic models that have been calibrated using gauge-based precipitation estimates. C1 [Johnson, Dennis] Michigan Technol Univ, Houghton, MI 49931 USA. [Smith, Michael; Koren, Victor] Natl Weather Serv, Hydrol Res Lab, Silver Spring, MD 20910 USA. [Finnerty, Bryce] Dewberry & Davis, Arlington, VA USA. RP Johnson, D (reprint author), Michigan Technol Univ, 312 Chem Sci Build,1400 Townsend Dr, Houghton, MI 49931 USA. EM dennisj@mtu.edu; mbs@skipper.nws.noaa.gov; vkoren@skipper.nws.noaa.gov NR 21 TC 57 Z9 57 U1 0 U2 6 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 1999 VL 4 IS 2 BP 117 EP 124 DI 10.1061/(ASCE)1084-0699(1999)4:2(117) PG 8 WC Engineering, Civil; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA V15AQ UT WOS:000207775300004 ER PT J AU Varmer, O AF Varmer, O TI The case against the "salvage" of the cultural heritage SO JOURNAL OF MARITIME LAW AND COMMERCE LA English DT Article; Proceedings Paper CT 2nd Newport Symposium on Sunken Treasure - Law, Technology, and Ethics CY AUG, 1998 CL NEWPORT, RHODE ISLAND C1 Natl Ocean & Atmospher Adm, Off Gen Counsel Int Law, Silver Spring, MD 20910 USA. RP Varmer, O (reprint author), Natl Ocean & Atmospher Adm, Off Gen Counsel Int Law, Silver Spring, MD 20910 USA. NR 4 TC 9 Z9 9 U1 1 U2 1 PU JEFFERSON LAW BOOK COMPANY PI BALTIMORE PA 2100 HUNTINGDON AVE, BALTIMORE, MD 21211 USA SN 0022-2410 J9 J MARIT LAW COMMER JI J. Marit. Law Commer. PD APR PY 1999 VL 30 IS 2 BP 279 EP 302 PG 24 WC International Relations; Law SC International Relations; Government & Law GA 177GA UT WOS:000079201200012 ER PT J AU Kerch, HM Long, GG Krueger, S Allen, AJ Gerhardt, R Cosandey, F AF Kerch, HM Long, GG Krueger, S Allen, AJ Gerhardt, R Cosandey, F TI Characterization of porosity over many length scales: Application to colloidal gels SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ANGLE NEUTRON-SCATTERING; X-RAY-SCATTERING; OF-STANDARDS; SILICA; GLASSES; MICROSCOPY AB Processing-microstructure relationships in a silica gel system, based on mixtures of colloidal sol and soluble potassium silicate, have been studied. Quantitative microstructural information regarding colloidal cluster sizes, size distributions, surface areas, and pore-size distribution from the nanopore range to the macropore range was determined via small-angle scattering and transmission electron microscopy. The colloid cluster size distribution varies systematically, with gels fabricated with the least colloidal fraction possessing the most polydisperse microstructure. It is shown that the porosity over the entire range can be tailored by selecting the appropriate starting chemistry; under the same pH conditions, the ratio of the two silicate ingredients controls the average size, the polydispersity of sizes, and the connectivity of the pores. A population of fine (2 nm) uniformly dispersed nanopores, which result from leaching, is responsible for large increases in surface area. The leaching process can be controlled by the surrounding macropore void size, which determines alkali transport. The product material consists of 85% large, open pores, with fine pores within the gel skeleton, making this gel an ideal candidate for controlled-porosity applications such as catalyst supports and magnetic composites. C1 US Dept Energy, Germantown, MD 20874 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. Rutgers State Univ, Piscataway, NJ 08855 USA. RP Kerch, HM (reprint author), US Dept Energy, Germantown, MD 20874 USA. RI Gerhardt, Rosario/D-6573-2012 OI Gerhardt, Rosario/0000-0001-8774-0842 NR 27 TC 4 Z9 4 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 APR PY 1999 VL 14 IS 4 BP 1444 EP 1454 DI 10.1557/JMR.1999.0195 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 235PC UT WOS:000082550400041 ER PT J AU Ehrman, SH Aquino-Class, MI Zachariah, MR AF Ehrman, SH Aquino-Class, MI Zachariah, MR TI Effect of temperature and vapor-phase encapsulation on particle growth and morphology SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID AEROSOLS; TITANIA; SILICA; FLAMES; SIZE AB The effect of in situ vapor phase salt-encapsulation on particle size and morphology was systematically investigated in a sodium co-flow/furnace reactor. The temperature of the furnace was varied, and the primary particle size and degree of agglomeration of the resulting silicon and germanium particles were determined from transmission electron micrograph images of particles sampled in situ. Particle size increased with increasing temperature, a trend expected from our understanding of particle formation in a high-temperature process in the absence of an encapsulant. Germanium, which coalesces faster than silicon, formed larger particles than silicon at the same temperatures, also in agreement with observations of particle growth in more traditional aerosol processes. At the highest temperatures, unagglomerated particles were formed, while at low temperatures, agglomerated particles were formed, with agglomerate shape following the shape of the salt coating. C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Ehrman, SH (reprint author), NIST, Chem Sci & Technol Lab, Bldg 221,Room B312, Gaithersburg, MD 20899 USA. NR 28 TC 23 Z9 24 U1 0 U2 8 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD APR PY 1999 VL 14 IS 4 BP 1664 EP 1671 DI 10.1557/JMR.1999.0224 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 235PC UT WOS:000082550400070 ER PT J AU Mekhtiev, MA Godfrey, PD Hougen, JT AF Mekhtiev, MA Godfrey, PD Hougen, JT TI Linestrengths of torsion-rotation transitions of methanol for J <= 22,K <= 14, and v(t)<= 2 from Hamiltonian-based calculations SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID MOLECULES; SPECTRUM AB Linestrengths have been obtained for methanol based on matrix elements of the dipole moment operator evaluated in a set of torsion-relation eigenfunctions. The latter were obtained from the parameters and effective Hamiltonian giving the best spectral fit available for a data set containing J less than or equal to 20, K less than or equal to 14, and upsilon(t) less than or equal to 1 microwave and far infrared transitions. The dipole moment function was represented as a Fourier expansion in the torsional angle gamma. Values for the permanent components mu(a) and mu(b) were obtained from experiment; values for their cos 3 gamma variation and for the sin 3 gamma variation of mu(c) were obtained from quantum chemistry molecular orbital calculations. The approach described allows calculation of the linestrength for any transition which satisfies the general selection rule A(1) <-> A(2) or E <-> E. A complete set of such linestrengths for all methanol torsion-rotation transitions involving levels with J less than or equal to 22, K less than or equal to 14, and upsilon(t) less than or equal to 2, and with intensities and frequencies above the rather small cutoff limits of 10(-6) D-2 and 1 kHz, respectively, together with individual contributions from the permanent and gamma-varying dipole moment components, have been tabulated and are available on request (ftp.monash.edu.au/pub/chem/1998a). (C) 1999 Academic Press. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. Monash Univ, Dept Chem, Ctr High Resolut Spect Optoelect Technol, Melbourne, Vic 3168, Australia. RP Mekhtiev, MA (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 17 TC 35 Z9 35 U1 1 U2 5 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 1999 VL 194 IS 2 BP 171 EP 178 DI 10.1006/jmsp.1998.7782 PG 8 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 182MF UT WOS:000079502200004 ER PT J AU Domenech, JL Bermejo, D Flaud, JM Lafferty, WJ AF Domenech, JL Bermejo, D Flaud, JM Lafferty, WJ TI The high-resolution Raman spectrum of the nu(4) band of diborane SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article AB The high-resolution Raman spectra of the nu(4) bands of (B2H6)-B-11 and (BBH6)-B-11-B-10 have been recorded and analyzed. The recordings have been made using a high-resolution spectrometer based on the inverse Raman effect. Q branches have been observed, but P and R branches were too weak to be seen, and simulations of the observed band contour have been necessary to complete the analysis. A weak Coriolis resonance with the 2 nu(10) level is present in the (B2H6)-B-11 spectrum. The band centers obtained are 790.9829(12) and 804.76985(27) cm(-1) for (B2H6)-B-11 and (BBH6)-B-10-B-11, respectively (uncertainties are type A with a coverage factor k = 1, i.e., 1 standard deviation). (C) 1999 Academic Press. C1 CSIC, Inst Estructura Mat, E-28006 Madrid, Spain. Univ Paris Sud, CNRS, Photophys Mol Lab, F-91405 Orsay, France. NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Domenech, JL (reprint author), CSIC, Inst Estructura Mat, Serrano 123, E-28006 Madrid, Spain. RI Domenech, Jose/F-5561-2013 OI Domenech, Jose/0000-0001-8629-2566 NR 16 TC 6 Z9 6 U1 0 U2 0 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 1999 VL 194 IS 2 BP 185 EP 188 DI 10.1006/jmsp.1998.7784 PG 4 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 182MF UT WOS:000079502200006 ER PT J AU Odashima, H Zink, LR Evenson, KM AF Odashima, H Zink, LR Evenson, KM TI Tunable far-infrared spectroscopy of (HCl)-Cl-35, and (HCl)-Cl-37 in the 6 to 9 THz region SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID ACCURATE ROTATIONAL-CONSTANTS; FREQUENCY MEASUREMENTS; HF C1 Toyama Univ, Dept Phys, Toyama 9308555, Japan. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Odashima, H (reprint author), Toyama Univ, Dept Phys, Gofuku 3190, Toyama 9308555, Japan. NR 9 TC 14 Z9 14 U1 0 U2 5 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 1999 VL 194 IS 2 BP 283 EP 284 DI 10.1006/jmsp.1998.7790 PG 2 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 182MF UT WOS:000079502200021 ER PT J AU Verplanck, PL Farmer, GL McCurry, M Mertzman, SA AF Verplanck, PL Farmer, GL McCurry, M Mertzman, SA TI The chemical and isotopic differentiation of an epizonal magma body: Organ Needle Pluton, New Mexico SO JOURNAL OF PETROLOGY LA English DT Article DE assimilation; enclave; epizonal pluton; isotope geochemistry; trace element geochemistry ID CRUSTAL CONTAMINATION; VOLCANIC-ROCKS; MAFIC ENCLAVES; BISHOP TUFF; SYSTEM; NEVADA; ORIGIN; SR; CRYSTALLIZATION; FRACTIONATION AB Major and trace element, and Nd and Sr isotopic compositions of whole rocks and mineral separates from the Oligocene, alkaline Organ Needle pluton (ONP), southern New Mexico, constrain models for the differentiation of the magma body parental to this compositionally zoned and layered epizonal intrusive body. The data reveal that the pluton is rimmed by lower epsilon(Nd) (similar to -5) and higher Sr-87/Sr-86 (similar to 0.7085) syenitic rocks than those in its interior (epsilon(Nd) similar to -2, Sr-87/Sr-86 -0.7060) and that the bulk compositions of the marginal rocks become more felsic with decreasing structural depth. At the deepest exposed levels of the pluton, the epsilon(Nd) similar to -5 lithology is a compositionally heterogeneous inequigranular syenite. Modal, compositional and isotopic data from separates of ran earth element (REE)-bearing major and accessory mineral phases (hornblende, titanite, apatite, zircon) demonstrate that this decoupling of trace and major elements in the inequigranular syenite results from accumulation of light REE (LREE)-bearing minerals that were evidently separated from silicic magmas as the latter rose along the sides of the magma chamber Chemical and isotopic data for microgranular mafic enclaves, as well as for restite xenoliths of Precambrian granite wall rock, indicate that the isotopic distinction between the marginal and interior facies of the ONP probably reflects assimilation of the wall rock by epsilon(Nd) similar to -2 mafic magmas near the base of the magma system. Fractional crystallization and crystal-liquid separation of the crustally contaminated magma at the bare and along the margins of the chamber generated the highly silicic magmas that ultimately pooled at the chamber top. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Idaho State Univ, Dept Geol, Pocatello, ID 83209 USA. Franklin & Marshall Coll, Dept Geosci, Lancaster, PA 17604 USA. RP Farmer, GL (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Campus Box 216, Boulder, CO 80309 USA. EM farmer@terra.colorado.edu NR 47 TC 24 Z9 28 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0022-3530 EI 1460-2415 J9 J PETROL JI J. Petrol. PD APR PY 1999 VL 40 IS 4 BP 653 EP 678 DI 10.1093/petrology/40.4.653 PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 186MX UT WOS:000079734500008 ER PT J AU Atakturk, SS Katsaros, KB AF Atakturk, SS Katsaros, KB TI Wind stress and surface waves observed on Lake Washington SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SEA-SURFACE; DRAG COEFFICIENT; HEAT-FLUX; GENERATED WAVES; MOMENTUM FLUX; WATER-VAPOR; AIR-FLOW; ROUGHNESS; DEPENDENCE; PRESSURE AB New results from turbulent flux measurements made over Lake Washington include the following: 1) The only direct measure of the vertical transport of the horizontal momentum, heat, and matter in the surface boundary layer is the so-called eddy correlation method. However, even if the measurement errors are negligible, the results obtained from point observations may show large scatter due to lack of stationarity and horizontal homogeneity in the turbulent held and to the sampling variability. Scatter may be greatly reduced by spatial averaging. In this study, such an effect is achieved by determining the surface roughness length, hence the neutral drag coefficient, from the measured wave height spectrum, which reflects the atmospheric input integrated over the fetch. Applicability and usefulness of the approach for general field measurements and remote sensing is discussed. 2) The evolution of the wave field observed on Lake Washington agrees in peak frequency and the slope of the equilibrium range parameter cu as a function of "wind forcing" with other observations, while the magnitude of cu is significantly smaller (by a factor of 2.1) than the values obtained from larger bodies of water. Based on the results obtained from a wave model, we attribute this observed difference to the narrower width of the water body on Lake Washington. These findings indicate that the state-of-the-art spectral parameterization of surface waves has limitations in describing the observations from a natural but small body of water. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. EM katsaros@aoml.noaa.gov NR 93 TC 23 Z9 25 U1 0 U2 6 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 APR PY 1999 VL 29 IS 4 BP 633 EP 650 DI 10.1175/1520-0485(1999)029<0633:WSASWO>2.0.CO;2 PG 18 WC Oceanography SC Oceanography GA 187VZ UT WOS:000079809900006 ER PT J AU Gomez-Gutierrez, J Peterson, WT AF Gomez-Gutierrez, J Peterson, WT TI Egg production rates of eight calanoid copepod species during summer 1997 off Newport, Oregon, USA SO JOURNAL OF PLANKTON RESEARCH LA English DT Article ID MARINE PLANKTONIC COPEPODS; BENGUELA UPWELLING SYSTEM; BODY-SIZE; PHYTOPLANKTON CONCENTRATION; LABORATORY OBSERVATIONS; EMBRYONIC-DEVELOPMENT; PSEUDOCALANUS SP; PHYSIO-ECOLOGY; GROWTH-RATES; PACIFICUS AB Measurements of hydrography, water transparency, chlorophyll (Chl) a and egg production rates (EPRs) by females of Calanus marshallae Frost, Calanus pacificus Brodsky, Eucalanus californicus Johnson, Epilabidocera longipedata Sate, Pseudocalanus mimus Frost, Centropages abdominalis Sate, Acartia longiremis Lilljerborg and Paracalanus pan us (Claus) were estimated at weekly intervals between 17 July and 2 September 1997. Production of eggs was determined in 24 h incubations to examine the effects of environmental variability on EPR, to detect the possibility of food limitation of EPR, and to evaluate the hypothesis that growth rates of females are size dependent. During the study, an anomalous downwelling event occurred, possibly in response to the 1997 El Nino, which allowed us to determine how El Nino events affect EPRs of coastal copepods. The larger copepods Calanus marshallae, Calanus pacificus and Centropages abdominalis showed the highest egg production and specific growth rates during the period of active upwelling (18 July-13 August, water temperatures 8-13 degrees C, Chi a concentration 4.7-16.2 mu g l(-1) and water transparency 3-5 m). After 27 August, the 1997-98 Fl Nino arrived off Oregon, creating a downwelling situation. Upwelling winds ceased, the thermocline intensified, temperature and transparency increased (to >18 degrees C and 16 m), and Chi a declined to <2 mu g l(-1). Densities of the common coastal species declined greatly as well. Paracalanus parvus became the dominant species, and Eucalanus californicus, Epilabidocera longipedata and Corycaeus anglicus became common in our samples. EPRs for the larger boreal copepods (Calanus and Ccntropages) declined greatly during El Nino; the smaller copepods, Pseudocalanus mimus, A. longiremis and Paracalanus parvus, showed low but relatively constant egg production and specific growth rates during both upwelling and downwelling events. Over the entire study period, only three species produced eggs at or very near their maximum: Calanus marshallae, which during the upwelling period produced eggs at its maximum rate (24-28 eggs female(-1) day(-1)), Pseudocalanus mimus which averaged similar to 4 eggs day(-1) and Calanus pacificus which averaged similar to 40 eggs day(-1). All other species had EPRs that were two or five times below their maximum EPR. Thus, EPRs were not related to body size, contrary to our expectations. Hatching success was variable among species. Values as low as 20-40% were found for all species at least once during the study period, suggesting that occasionally a substantial portion of egg production may not be viable. C1 Ctr Interdisciplinario Ciencias Marinas, Dept Plancton & Ecol Marina, La Paz 23000, Baja Calif Sur, Mexico. NOAA, NMFS, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Gomez-Gutierrez, J (reprint author), Oregon State Univ, Coll Ocean & Atmospher Sci, 104 Ocean Adm Bldg, Corvallis, OR 97331 USA. NR 38 TC 35 Z9 36 U1 0 U2 7 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0142-7873 EI 1464-3774 J9 J PLANKTON RES JI J. Plankton Res. PD APR PY 1999 VL 21 IS 4 BP 637 EP 657 DI 10.1093/plankt/21.4.637 PG 21 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 186JR UT WOS:000079726200003 ER PT J AU Khoury, F AF Khoury, F TI A crystalline polymer morphologist's perspective on the occasion of the centenary of the foundation of the American Physical Society SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Editorial Material ID ISOTACTIC POLYPROPYLENE C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Khoury, F (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 8 TC 0 Z9 0 U1 0 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD APR 1 PY 1999 VL 37 IS 7 BP 631 EP 633 PG 3 WC Polymer Science SC Polymer Science GA 176EM UT WOS:000079138200009 ER PT J AU Demer, DA Soule, MA Hewitt, RP AF Demer, DA Soule, MA Hewitt, RP TI A multiple-frequency method for potentially improving the accuracy and precision of in situ target strength measurements SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID BEAM ECHO-SOUNDER; SPECIES IDENTIFICATION; ZOOPLANKTON; BACKSCATTERING; DEPENDENCE; ABUNDANCE; SPHERES; SINGLE; KRILL AB The effectiveness of a split-beam echosounder system to reject echoes from unresolvable scatterers, thereby improving the measurements of in situ target strengths (TS) of individuals, is dramatically enhanced by combining synchronized signals from two or more adjacent split-beam transducers of different frequencies. The accuracy and precision of the method was determined through simulations and controlled test tank experiments using multiple standard spheres and 38- and 120-kHz split-beam echosounders. By utilizing the angular positional information from one of the split-beam transducers, additional corresponding TS measurements were shown to be obtainable from a juxtaposed single-beam transducer. Both methods were utilized to extract in situ TS measurements of Antarctic scatterers simultaneously at 38, 120, and 200 kHz. The ultimate efficiency of the multiple-frequency method is shown to be limited by phase measurement precision, which in turn is limited by the scattering complexity of targets, the signal-to-noise ratio, and the receiver bandwidth. Imprecise phase measurements also result in significant beam-compensation uncertainty in split-beam measurements. Differences in multi-frequency TS measurements provided information about the identity of constituents in a mixed species assemblage. The taxa delineation method has potential, but is limited by compounding measurement uncertainties at the individual frequencies and sparse spectral sampling. (C) 1999 Acoustical Society of America. [S0001-4966(99)01204-7]. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Sea Fisheries Res Inst, Cape Town, South Africa. RP Demer, DA (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 39 TC 50 Z9 50 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD APR PY 1999 VL 105 IS 4 BP 2359 EP 2376 DI 10.1121/1.426841 PG 18 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 188FW UT WOS:000079837000031 ER PT J AU Paik, U Hackley, VA Lee, HW AF Paik, U Hackley, VA Lee, HW TI Dispersant-binder interactions in aqueous silicon nitride suspensions SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID POLY(ACRYLIC ACID); SURFACE-CHEMISTRY; POLYVINYL-ALCOHOL; ADSORPTION; STABILITY; POWDER AB The interaction of dispersant and binder on the surface of particles was studied to identify the effect of these additives on aqueous ceramic powder processing. Poly(methacrylic acid) (PMAA) and poly(vinyl alcohol) (PVA) were used as the dispersant and binder, respectively. The adsorption isotherms of the organic additives on silicon nitride were determined. The adsorption of PMAA was differentiated from PVA in the mixed additive system via ultraviolet spectroscopy. The electrokinetic behavior of silicon nitride was measured by using an electrokinetic sonic amplitude analyzer. As the PMAA concentration increased, the isoelectric point (pH(iep)) of silicon nitride shifted from pH 6.7 +/- 0.1 to acidic pH values. The magnitude of the shift depended on the surface coverage of PMAA. PVA did not affect the pH(iep) of suspensions but did cause a moderate decrease in the near-surface potential. Finally, the rheological behavior of silicon nitride suspensions was measured to assess the stability of particles against flocculation in aqueous media; this behavior was subsequently correlated with the electrokinetic and adsorption isotherm data. C1 Changwon Natl Univ, Dept Mat Sci & Engn, Changwon 641773, Kyungnam, South Korea. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. KIST, Ceram Proc Ctr, Seoul 130650, South Korea. RP Paik, U (reprint author), Hanyang Univ, Dept Ceram Engn, Seoul 133, South Korea. NR 26 TC 82 Z9 84 U1 0 U2 10 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 APR PY 1999 VL 82 IS 4 BP 833 EP 840 PG 8 WC Materials Science, Ceramics SC Materials Science GA 189WK UT WOS:000079929000004 ER PT J AU Hsueh, CH Haynes, JA Lance, MJ Becher, PF Ferber, MK Fuller, ER Langer, SA Carter, WC Cannon, WR AF Hsueh, CH Haynes, JA Lance, MJ Becher, PF Ferber, MK Fuller, ER Langer, SA Carter, WC Cannon, WR TI Effects of interface roughness on residual stresses in thermal barrier coatings SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID OXIDATION-INDUCED STRESSES; BEHAVIOR; FILMS AB Using a newly developed object-oriented finite-element analysis method, both an actual microstructure and model microstructures of a plasma-sprayed thermal barrier coating system were numerically simulated to analyze the fullfield residual stresses of this coating system, Residual stresses in the actual microstructure were influenced by both the irregular top-coat/bond-coat interface and cracks in the top coat. By treating the microcracked top coat as a more-compliant solid microstructure, the effects of the irregular interface on residual stresses were examined. These results then could be compared to results that have been obtained by analyzing a model microstructure with a sinusoidal interface, which has been considered by some earlier investigators. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Rutgers State Univ, Dept Ceram & Mat Engn, Piscataway, NJ 08855 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; Carter, W/K-2406-2012; Lance, Michael/I-8417-2016 OI Lance, Michael/0000-0001-5167-5452 NR 12 TC 62 Z9 63 U1 1 U2 17 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 APR PY 1999 VL 82 IS 4 BP 1073 EP 1075 PG 3 WC Materials Science, Ceramics SC Materials Science GA 189WK UT WOS:000079929000039 ER PT J AU Ausloos, P Clifton, CL Lias, SG Mikaya, AI Stein, SE Tchekhovskoi, DV Sparkman, OD Zaikin, V Zhu, D AF Ausloos, P Clifton, CL Lias, SG Mikaya, AI Stein, SE Tchekhovskoi, DV Sparkman, OD Zaikin, V Zhu, D TI The critical evaluation of a comprehensive mass spectral library SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID SEARCH ALGORITHMS; IDENTIFICATION; DATABASES; OPTIMIZATION AB A description of the methods used to build a high quality, comprehensive reference library of electron-ionization mass spectra is presented. Emphasis is placed on the most challenging part of this project-the improvement of quality by expert evaluation. The methods employed for this task were developed over the course of a spectrum-by-spectrum review of a library containing well over 100,000 spectra. Although the effectiveness of this quality improvement task depended critically on the expertise of the evaluators, a number of guidelines are discussed which were found to be effective in performing this onerous and often subjective task. A number of specific examples of the particularly challenging task of spectrum editing are given. (C) 1999 American Society for Mass Spectrometry. C1 NIST, Mass Spectrometry Data Ctr, Gaithersburg, MD 20899 USA. Sparkman & Associates, Antioch, CA USA. AV Topchiev Petrochem Synth Inst, Moscow, Russia. Chinese Acad Sci, Dalian Inst Chem Phys, Dalian, Peoples R China. RP Stein, SE (reprint author), NIST, Mass Spectrometry Data Ctr, A111-221, Gaithersburg, MD 20899 USA. RI Tchekhovskoi, Dmitrii/J-2319-2014 NR 23 TC 111 Z9 115 U1 2 U2 14 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD APR PY 1999 VL 10 IS 4 BP 287 EP 299 DI 10.1016/S1044-0305(98)00159-7 PG 13 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 221PP UT WOS:000081735700001 PM 10197350 ER PT J AU Kushner, PJ Held, IM AF Kushner, PJ Held, IM TI Potential vorticity thickness fluxes and wave-mean flow interaction SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID QUASI-GEOSTROPHIC EDDIES; OCEAN CIRCULATION MODELS; TRANSIENT; PROPAGATION AB The use of eddy flux of thickness between density surfaces has become a Familiar starting point in oceanographic studies of adiabatic eddy effects on the mean density distribution. In this study, a dynamical analogy with the density thickness flux approach is explored to reexamine the theory of nonzonal wave-mean now interaction in two-dimensional horizontal flows. By analogy with the density thickness flux, the flux of thickness between potential vorticity (PV) surfaces is used as a starting point for a residual circulation formulation for nonzonal mean flows. Mean equations for barotropic PV dynamics are derived in which a modified mean velocity with an eddy-induced component advects a modified mean PV that also has an eddy-induced component. For small-amplitude eddies, the results are analogous to recent results of McDougall and McIntosh derived for stratified flow. The dynamical implications of this approach are then examined. The modified mean PV equation provides a decomposition of the eddy forcing of the mean how into contributions from wave transience, wave dissipation, and wave-induced mass redistribution between PV contours. If the mean flow is along the mean PV contours, the contribution from wave-induced mass redistribution is "workless" in Plumb's sense that it is equivalent to an eddy-induced stress that is perpendicular to the mean flow. This contribution is also associated with the convergence along the mean streamlines of a modified PV flux that is equal to the difference between the PV flux and the rotational PV flux term identified by Illari and Marshall. The cross-stream component of the modified PV flux is related to wave transience and dissipation. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Kushner, PJ (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. RI Kushner, Paul/H-6716-2016 OI Kushner, Paul/0000-0002-6404-4518 NR 19 TC 8 Z9 8 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 APR 1 PY 1999 VL 56 IS 7 BP 948 EP 958 DI 10.1175/1520-0469(1999)056<0948:PVTFAW>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 178PF UT WOS:000079274500004 ER PT J AU Hong, SY Juang, HMH Lee, DK AF Hong, SY Juang, HMH Lee, DK TI Evaluation of a regional spectral model for the East Asian monsoon case studies for July 1987 and 1988 SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID LATERAL BOUNDARY-CONDITIONS; RANGE FORECAST MODEL; LIMITED-AREA MODEL; LOW-LEVEL JET; MEI-YU FRONT; CLIMATE MODEL; SUMMER MONSOON; PARAMETERIZATION SCHEME; WEATHER PREDICTION; SOIL HYDROLOGY AB This study examines the National Centers for Environmental Prediction Regional Spectral Model (NCEP RSM)'s capability as a tool for providing regional climate details over East Asia during the summertime. Toward this end, perfect boundary condition experiments driven by analysis data are performed. The NCEP-National Center for Atmospheric Research (NCAR) re-analysis is used to provide large-scale forcings for the RSM configured with an approximately 25-km grid over East Asia centered on the Korean peninsula. Month-long simulations are conducted for July, which is the major monsoon precipitation period for Korea. The selected years are 1987 and 1988, which correspond to an El Nino and La Nina year, respectively. Overall, the model results are satisfactory in terms of the simulated large-scale features for the different years. Deviation of the simulated large-scale features from the analysis generally remains small. Domain averaged error of the simulated temperature shows a maximum of 0.8K at 300 hPa, and relative humidity less than 2 % within the entire troposphere. A discernible bias is found in the simulated climate, including a warming in the northern part and a cooling in the southern part of the domain in the lower troposphere. Cooling is dominant in the middle and upper troposphere, with values less than 1K in much of the domain. This deviation commonly appears for both years, indicating that the anomaly forecasts relative to a RSM climatology can alleviate uncertainties related to a RSM systematic error. The monthly accumulated precipitation simulated by the RSM compares well with the observations in terms of anomalous precipitation patterns for the two different summers. Regional features, including a local maximum and minimum, are not reproduced well in the RSM. However, the amount of the domain-averaged precipitation for a month is nearly the same as that recorded by observations. The skill of providing the daily variation of simulated precipitation over Korea is relatively poor. Evolution of the daily precipitation in the simulations generally compares with the observations qualitatively, but the amount and onset of precipitation events are not well reproduced. The two severe weather events causing disastrous rainfall over Korea, a tropical cyclone and a mesoscale convective system, are evaluated in detail. C1 Natl Ctr Environm Predict, Environm Moleling Ctr, Washington, DC USA. Natl Ctr Environm Predict, Climate Predict Ctr, Washington, DC USA. Seoul Natl Univ, Dept Atmospher Sci, Seoul, South Korea. RP Hong, SY (reprint author), Room 207,5200 Auth Rd, Camp Springs, MD 20746 USA. EM Songyou.Hong@noaa.gov RI Hong, Song-You/I-3824-2012 NR 44 TC 20 Z9 25 U1 0 U2 1 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD APR PY 1999 VL 77 IS 2 BP 553 EP 572 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 210UB UT WOS:000081122100011 ER PT J AU Mukherjea, A Nakassis, A Ratti, JS AF Mukherjea, A Nakassis, A Ratti, JS TI On the distribution of the limit of products of IID 2 x 2 random stochastic matrices SO JOURNAL OF THEORETICAL PROBABILITY LA English DT Article DE random matrices; limit distribution AB This article gives sufficient conditions for the limit distribution of products of i.i.d. 2x2 random stochastic matrices to be continuous singular. when the support of the distribution of the: individual random matrices is finite. C1 Univ S Florida, Dept Math, Tampa, FL 33620 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mukherjea, A (reprint author), Univ S Florida, Dept Math, Tampa, FL 33620 USA. NR 7 TC 3 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0894-9840 J9 J THEOR PROBAB JI J. Theor. Probab. PD APR PY 1999 VL 12 IS 2 BP 571 EP 583 DI 10.1023/A:1021694515077 PG 13 WC Statistics & Probability SC Mathematics GA 218VG UT WOS:000081573200015 ER PT J AU Brill, RW Block, BA Boggs, CH Bigelow, KA Freund, EV Marcinek, DJ AF Brill, RW Block, BA Boggs, CH Bigelow, KA Freund, EV Marcinek, DJ TI Horizontal movements and depth distribution of large adult yellowfin tuna (Thunnus albacares) near the Hawaiian Islands, recorded using ultrasonic telemetry: implications for the physiological ecology of pelagic fishes SO MARINE BIOLOGY LA English DT Article ID KATSUWONUS-PELAMIS; BLUE MARLIN; SKIPJACK TUNA; CARDIOVASCULAR-RESPONSES; AGGREGATION DEVICES; VERTICAL MOVEMENTS; MAKAIRA-NIGRICANS; OXYGEN-TRANSPORT; FEEDING-HABITS; ACUTE-HYPOXIA AB We measured the horizontal and vertical movements of five adult yellowfin tuna (Thunnus albacares, estimated body mass 64 to 93 kg) near the main Hawaiian Islands, while simultaneously gathering data on oceanographic conditions and currents. Fish movements were recorded by means of ultrasonic depth-sensitive transmitters. Depth-temperature and depth-oxygen profiles were measured with vertical conductivity-temperature-depth (CTD) casts, and the current-velocity field was surveyed using an acoustic Doppler current profiler (ADCP). Large adult yellowfin tuna spent similar or equal to 60 to 80% of their time in or immediately below the relatively uniform-temperature surface-layer (i.e. above 100 m), a behavior pattern similar to that previously reported for juvenile yellowfin tuna, blue marlin (Makaira nigricans), and striped marlin (Tetrapturus audax) tracked in the same area. In all three species. maximum swimming depths appear to be limited by water temperatures 8 C degrees colder than the surface-layer water temperature. Therefore, neither large body mass, nor the ability to maintain elevated swimming-muscle temperatures due to the presence of vascular countercurrent heat exchangers in tunas, appears to permit greater vertical mobility or the ability to remain for extended periods below the thermocline. In those areas where the decrease in oxygen with depth is not limiting, the vertical movements of yellowfin tuna, blue marlin and striped merlin all appear to be restricted by the effects of water temperature on cardiac muscle function. Like juvenile yellowfin tuna, but unlike blue marlin and striped marlin, adult yellowfin tuna remained within 18.5 km of the coast and became associated with floating objects, including anchored fish-aggregating devices (FADs) and the tracking vessel. Like juvenile yellowfin tuna, large adult yellowfin repeatedly re-visit the same FAD, and appear able to navigate precisely between FADs that are up to 18 km apart. The median speed over ground ranged from 72 to 154 cm s(-1). Neither speed nor direction was strongly influenced by currents. C1 NOAA, Natl Marine Fisheries Serv, Honolulu, HI 96822 USA. Univ Hawaii Manoa, Sch Earth Sci & Technol, Joint Inst Marine & Atmospher Res, Pelag Fisheries Res Program, Honolulu, HI 96822 USA. Stanford Univ, Hopkins Marine Stn, Tuna Res & Conservat Ctr, Pacific Grove, CA 93950 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Brill, RW (reprint author), NOAA, Natl Marine Fisheries Serv, 2570 Dole St, Honolulu, HI 96822 USA. OI Marcinek, David/0000-0001-5187-2149 NR 66 TC 146 Z9 165 U1 1 U2 25 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD APR PY 1999 VL 133 IS 3 BP 395 EP 408 DI 10.1007/s002270050478 PG 14 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 189DJ UT WOS:000079888600002 ER PT J AU Ferrero, RC Walker, WA AF Ferrero, RC Walker, WA TI Age, growth, and reproductive patterns of Dall's porpoise (Phocoenoides dalli) in the central North Pacific Ocean SO MARINE MAMMAL SCIENCE LA English DT Article DE Dall's porpoise; Phocoenoides dalli; reproduction; growth patterns; life history; age estimation ID EASTERN TROPICAL PACIFIC; STENELLA-ATTENUATA; HARBOR PORPOISES; OFFSHORE WATERS; LIFE-HISTORY; DOLPHIN; SEA; LINNAEUS; OKHOTSK; CETACEA AB Life history parameters were estimated for Dall's porpoise, Phocoenoides dalli, from biological specimens collected in the western Aleutian Islands, during 1981-1987. Of 2,033 males and 3,566 females examined, reproductive data were available for 1,941 males and 1,906 females; ages were determined for 813 males and 1,297 females. Female sexual maturity was based on the presence of one or more corpus on either ovary; 845 were sexually immature and 1,061 were sexually mature. Two estimates of female average age at sexual maturity (ASM) were 3.8 and 4.4 yr; average length at sexual maturity (LSM) was 172 cm. Males were considered sexually mature when evidence of spermatogenesis was detected; 1,136 were sexually immature and 805 were sexually mature. Two estimates of male ASM were 4.5 and 5.0 yr; LSM was 179.7 cm. Physical maturity was assessed for 246 males and 446 females by examining the degree of fusion in thoracic vertebral epiphyses. For both sexes, the average age at physical maturity was 7.2 yr. Average length at physical maturity was 202.6 cm for males and 192.7 cm for females. Average lengths of physically mature males ((x) over bar = 198.1 cm, SE = 0.8566) and females ((x) over bar = 189.7 cm, SE = 0.4002) were significantly different(P < 0.0001). Early postnatal growth was rapid in both sexes. A secondary growth spurt in both mass and length was characteristic for both sexes; the increase in length preceded the mass increase by 1-2 yr. Average length at birth (LOB) was approximately 100 cm; birth mass averaged 11.3 kg (SE = 0.0772). By the time the umbilicus had healed (<2 mo), the average length and mass had increased to 114.1 cm, and 23.8 kg, respectively. Gestation period based on projections using LOB was 12 mo, but this was considered an overestimate. Calving was modal, centered in early July; an annual reproductive interval was indicated. Among the sexually mature females, 120 were pregnant, 55 were pregnant and lactating, 321 were pregnant with colostrum, and 33 were "resting." By 3 July (95% CI = +/- 1 d), 50% of births had occurred, during each of the seven years sampled. The ovulation rate was estimated at 0.914 ovulations per average reproductive year. Enlarged follicles and recent ovulations were observed in postpartum females in late July. C1 Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, NOAA, Seattle, WA 98115 USA. RP Ferrero, RC (reprint author), Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, NOAA, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 53 TC 32 Z9 34 U1 2 U2 6 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 1999 VL 15 IS 2 BP 273 EP 313 DI 10.1111/j.1748-7692.1999.tb00803.x PG 41 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 188AH UT WOS:000079821000001 ER PT J AU Perryman, WL Donahue, MA Laake, JL Martin, TE AF Perryman, WL Donahue, MA Laake, JL Martin, TE TI Diel variation in migration rates of eastern Pacific gray whales measured with thermal imaging sensors SO MARINE MAMMAL SCIENCE LA English DT Article DE cetacean; gray whale; Eschrichtius robustus; infrared; detection; migration; abundance estimation; thermal sensor ID WHITE-TAILED DEER; AERIAL AB We recorded the blows of gray whales during their southbound migration past central California in January 1994, 1995, and 1996, using thermal imaging sensors. For our sampling purposes, we defined day (0730-1630) and night (1630-0730) to coincide with the on/off effort periods of the visual counts being conducted concurrently We pooled data across the three years of sampling and tested for diel variation in surfacing interval, pod size, offshore distance, migration rate, and swimming speed by comparing paired day/night means for samples collected within the respective 24-h period. We performed these tests using data from the entire migration period and then repeated the tests for samples collected prior to and after the approximate median migration date (15 January). Over the entire migration period we observed larger diurnal pod sizes ((x) over bar(day) = 1.75 +/- 0.280, (x) over bar(night) = 1.63 +/- 0.232) and greater diurnal offshore distances ((x) over bar(day) = 2.30 +/- 0.328 km, (x) over bar(night) = 2.03 +/- 0.356 km) but found no diel variation in surfacing interval. For the entire migration period, the nocturnal migration rate (average number of whales passing per hour) was higher than the diurnal rate. During the first half of the migration we detected no diel variation in pod size or surfacing interval, but diurnal offshore distances were larger than at night ((x) over bar(day) = 2.28 +/- 0.273 km, (x) over bar(night) = 1.96 +/- 0.318 km). Diurnal and noctural migration rates prior to 15 January were not different. During the second half of the migration, there was no diel variation in surfacing interval, pod site, or distance offshore, but the nocturnal migration rate was higher (28%, SE = 11.6%) than the diurnal rate. We found no diel variation in swimming speed in any comparison. We propose thar later migrants socialite more during the day, which effectively slows their diurnal rate of migration relative to nocturnal rates. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. NOAA, Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Seattle, WA 98115 USA. RP Perryman, WL (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 26 TC 15 Z9 16 U1 2 U2 8 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 1999 VL 15 IS 2 BP 426 EP 445 DI 10.1111/j.1748-7692.1999.tb00811.x PG 20 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 188AH UT WOS:000079821000009 ER PT J AU Pitman, RL Palacios, DM Brennan, PLR Brennan, BJ Balcomb, KC Miyashita, T AF Pitman, RL Palacios, DM Brennan, PLR Brennan, BJ Balcomb, KC Miyashita, T TI Sightings and possible identity of a bottlenose whale in the tropical Indo-Pacific: Indopacetus pacificus? SO MARINE MAMMAL SCIENCE LA English DT Article ID NOSED-WHALES C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Whale Conservat Inst, Lincoln, MA 01773 USA. Ctr Whale Res Inc, Friday Harbor, WA 98250 USA. Natl Res Inst Far Seas Fisheries, Shimizu, Shizuoka 424, Japan. Fdn Yubarta, Cali, Colombia. RP Pitman, RL (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. RI Palacios, Daniel/B-9180-2008 OI Palacios, Daniel/0000-0001-7069-7913 NR 37 TC 15 Z9 23 U1 0 U2 4 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD APR PY 1999 VL 15 IS 2 BP 531 EP 549 DI 10.1111/j.1748-7692.1999.tb00818.x PG 19 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 188AH UT WOS:000079821000016 ER PT J AU Bentz, DP AF Bentz, DP TI Modelling cement microstructure: Pixels, particles, and property prediction SO MATERIALS AND STRUCTURES LA English DT Article ID CELLULAR-AUTOMATON MODEL; PORTLAND-CEMENT; COMPUTER-SIMULATION; POROUS-MEDIA; HYDRATION; TRANSPORT; PERCOLATION; DIFFUSIVITY; PASTE AB During the past ten years, a comprehensive model for the three-dimensional microstructural development of cement paste during hydration has been developed and validated. The model employs a number of computational and analytical tools including cellular automata, digital image processing and reconstruction, percolation theory, and the maturity method. The model has been successfully applied to predicting the percolation and diffusion properties of cement pastes. Through a kinetics calibration, the evolution of:heat release, chemical shrinkage, and compressive strength with time have been predicted. The variation of curing temperature and availability of external curing water can also be simulated using the developed model. This paper reviews the computational tools employed in the model, summarizes the experimental and modelling approaches, and presents representative predicted properties. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 50 TC 26 Z9 28 U1 1 U2 6 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1359-5997 J9 MATER STRUCT JI Mater. Struct. PD APR PY 1999 VL 32 IS 217 BP 187 EP 195 DI 10.1007/BF02481514 PG 9 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 187DF UT WOS:000079770500007 ER PT J AU Williamson, JF Coursey, BM DeWerd, LA Hanson, WF Nath, R Ibbott, G AF Williamson, JF Coursey, BM DeWerd, LA Hanson, WF Nath, R Ibbott, G TI Guidance to users of Nycomed Amersham and North American Scientific, Inc., I-125 Interstitial Sources: Dosimetry and calibration changes: Recommendations of the American Association of Physicists in Medicine Radiation Therapy Committee Ad Hoc Subcommittee on Low-Energy Seed Dosimetry SO MEDICAL PHYSICS LA English DT Article DE brachytherapy; I-125 seeds; dosimetry; air-kerma strength; primary standard; dose-rate constant; Task Group 43 ID BRACHYTHERAPY AB Dose calculations to patients undergoing implantation of I-125 interstitial brachytherapy sources are affected by two recent changes in low-energy seed dosimetry: (a) implantation of a new primary air-kerma strength standard at the National Institute of Standards and Technology (NIST) on 1 January 1999 and (b) publication of revised dose-rate distributions in AAPM's Task Group 43 Report. The guidance herein represents AAPM's recommendations for users of I-125 interstitial seed products marketed prior to 1 January 1999 (Nycomed Amersham models 6711 and 6702 and North American Scientific, Inc. models 3631 A/S and 3631 A/M. Implementation of Task Group 43 (TG43) I-125 dose calculations involves revising data stored in files of radiation treatment planning software and lowering the prescribed dose to be delivered to patients by as much as 15% to avoid modifying the dose actually delivered to patients. The magnitude of the dose prescription change depends on the dosimetry data used prior to TG43 and the implant geometry. Adapting to the revised NIST calibration standard requires the user to increase the dose-rate constant (or its equivalent by 11.5%) but does not require modification of the prescribed dose. Failure to correctly implement these modifications can result in 20% or even 30% errors. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)02804-7]. C1 Washington Univ, Med Ctr, Ctr Radiat Oncol, St Louis, MO 63110 USA. Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. Univ Wisconsin, Radiat Calibrat Labs, Madison, WI 53706 USA. Univ Texas, MD Anderson Canc Ctr, Dept Radiat Phys, Houston, TX 77030 USA. Yale Univ, Sch Med, Dept Therapeut Radiol, New Haven, CT 06510 USA. Univ Kentucky, Dept Radiat Med, Lexington, KY 40536 USA. RP Williamson, JF (reprint author), Washington Univ, Med Ctr, Ctr Radiat Oncol, 510 S Kingshighway Blvd, St Louis, MO 63110 USA. NR 9 TC 79 Z9 91 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD APR PY 1999 VL 26 IS 4 BP 570 EP 573 DI 10.1118/1.598570 PG 4 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 187CW UT WOS:000079769500014 PM 10227361 ER PT J AU Schwartz, LH AF Schwartz, LH TI Sustainability: The materials role SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Editorial Material AB This lecture series began in 1971 focused on the links between materials, energy, and the environment. The issue of sustainability had emerged, but only as an exploration of the possibility of materials depletion in the face of predicted population growth. Today, sustainability implies a global economic and social system that both satisfies human needs and does not despoil the earth. What has been our role in this increasingly important arena of human concern and what should it be? Our report card is impressive. Improvements in processing, in materials substitution, in design to minimize materials usage, and in recycling of metals and polymers have all been remarkable. However, we are faced with twin dreadnoughts of change in the next decades: technological ascendency of developing nations and rising world population. Add to these the need to reduce the effluence of greenhouse gases and we must anticipate formidable technological upheaval throughout the materials cycle. Our professional societies need to step forward and play larger and significantly more visible roles in this arena, Working individually and in concert with others, the societies must broadcast our achievements, identify future areas for activity, support industrial road-mapping efforts, and join with all who will participate in clarifying the flow of materials throughout their life cycles. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 27 TC 1 Z9 1 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD APR PY 1999 VL 30 IS 4 BP 895 EP 908 DI 10.1007/s11661-999-0143-4 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 180XK UT WOS:000079411000001 ER PT J AU Schwartz, LH AF Schwartz, LH TI Sustainability: The materials role SO METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE LA English DT Article AB This lecture series began in 1971 focused on the links between materials, energy, and the environment. The issue of sustainability had emerged, but only as an exploration of the possibility of materials depletion in the face of predicted population growth. Today, sustainability implies a global economic and social system that both satisfies human needs and does not despoil the earth, What has been our role in this increasingly important arena of human concern and what should it be? Our report card is impressive. Improvements in processing, in materials substitution, in design to minimize materials usage, and in recycling of metals and polymers have all been remarkable, However, we are faced with twin dreadnoughts of change in the next decades: technological ascendency of developing nations and rising world population. Add to these the need to reduce the effluence of greenhouse gases and we must anticipate formidable technological upheaval throughout the materials cycle. Our professional societies need to step forward and play larger and significantly more visible roles in this arena. Working individually and in concert with others, the societies must broadcast our achievements, identify future areas for activity, support industrial road-mapping efforts, and join with all who will participate in clarifying the flow of materials throughout their life cycles. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 25 TC 3 Z9 3 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5615 J9 METALL MATER TRANS B JI Metall. Mater. Trans. B-Proc. Metall. Mater. Proc. Sci. PD APR PY 1999 VL 30 IS 2 BP 157 EP 170 DI 10.1007/s11663-999-0045-2 PG 14 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 181GN UT WOS:000079433300001 ER PT J AU Rocha-Olivares, A Kimbrell, CA Eitner, BJ Vetter, RD AF Rocha-Olivares, A Kimbrell, CA Eitner, BJ Vetter, RD TI Evolution of a mitochondrial cytochrome b gene sequence in the species-rich genus Sebastes (Teleostei, Scorpaenidae) and its utility in testing the monophyly of the subgenus Sebastomus SO MOLECULAR PHYLOGENETICS AND EVOLUTION LA English DT Article ID DEPENDENT PERMUTATION TEST; PHYLOGENETIC TREES; MAXIMUM-LIKELIHOOD; DNA-SEQUENCES; SUBSTITUTIONS; CONFIDENCE; MAMMALS; GENOME; RATES AB The ecologically diverse and species-rich rockfishes (Sebastes) are a useful group for the study of marine speciation. The monophyly of the genus is generally accepted, as is the validity of most of the numerous species found along the West Coast of North America. However, the subgeneric groupings that would help in the proposal and interpretation of various speciation schemes are poorly supported based on widely overlapping morphological characters. The use of genetic characters provides an alternative approach. In this study, we present the first quantitative analysis supporting the monophyly of all 14 species of the subgenus Sebastomus among 54 congeners. The structural features and evolution of the 750 bp of the cytochrome b gene used to test the monophyly were similar to those of other vertebrates. Low levels of intrageneric sequence divergence (<10%) and incipient levels of saturation at third-codon positions were found in the gene. The monophyly of Sebastomus was supported in extensive phylogenetic analyses using distance, cladistic, and likelihood methods. Further corroboration was obtained from permutation- and simulation-based statistical tests. (C) 1999 Academic Press. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Rocha-Olivares, A (reprint author), Louisiana State Univ, Dept Biol Sci, 508 LSB, Baton Rouge, LA 70803 USA. RI Rocha-Olivares, Axayacatl/A-9832-2008 OI Rocha-Olivares, Axayacatl/0000-0002-2700-9086 NR 67 TC 55 Z9 55 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1055-7903 J9 MOL PHYLOGENET EVOL JI Mol. Phylogenet. Evol. PD APR PY 1999 VL 11 IS 3 BP 426 EP 440 DI 10.1006/mpev.1998.0584 PG 15 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 188RK UT WOS:000079862100008 PM 10196083 ER PT J AU Rocha-Olivares, A Rosenblatt, RH Vetter, RD AF Rocha-Olivares, A Rosenblatt, RH Vetter, RD TI Molecular evolution, systematics, and zoogeography of the rockfish subgenus Sebastomus (Sebastes, Scorpaenidae) based on mitochondrial cytochrome b and control region sequences SO MOLECULAR PHYLOGENETICS AND EVOLUTION LA English DT Article ID DNA-SEQUENCES; CICHLID FISHES; PATTERNS; GENE; SUBSTITUTIONS; MAMMALS; CONTEXT; TREES; RATES AB Sebastomus is one of the most species-rich subgenera of Sebastes, whose monophyly is well supported by morphological and molecular data. We present the first description of the complete nucleotide sequence of the mitochondrial cytochrome b gene and the partial sequence of the control region of the 14 species of Sebastomus. We used these data in phylogenetic analyses to investigate their evolutionary relationships. Extremely low levels of sequence divergence indicated a recent ancestry of these species, suggesting a very rapid radiation within the last million years. The molecular data revealed two main clades within Sebastomus, each with species of different affinities that invaded new habitats from the subgeneric center of distribution. The rapid speciation in this lineage was manifested in the poor resolution of some nodes in the phylogeny. Internal fertilization and viviparity in Sebastes may have played an important role in the sudden acquisition of reproductive barriers during its radiation. The mitochondrial DNA data suggest that prolific speciation in Sebastomus may have been associated with rapid lineage sorting punctuated by allopatric reproductive isolation subsequent to dispersal events and, perhaps, by sympatric reproductive isolation associated with internal fertilization. (C) 1999 Academic Press. C1 Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Rocha-Olivares, A (reprint author), Louisiana State Univ, Dept Biol Sci, 508 LSB, Baton Rouge, LA 70803 USA. RI Rocha-Olivares, Axayacatl/A-9832-2008 OI Rocha-Olivares, Axayacatl/0000-0002-2700-9086 NR 72 TC 74 Z9 78 U1 0 U2 8 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1055-7903 J9 MOL PHYLOGENET EVOL JI Mol. Phylogenet. Evol. PD APR PY 1999 VL 11 IS 3 BP 441 EP 458 DI 10.1006/mpev.1998.0585 PG 18 WC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity SC Biochemistry & Molecular Biology; Evolutionary Biology; Genetics & Heredity GA 188RK UT WOS:000079862100009 PM 10196084 ER PT J AU Stensrud, DJ Brooks, HE Du, J Tracton, MS Rogers, E AF Stensrud, DJ Brooks, HE Du, J Tracton, MS Rogers, E TI Using ensembles for short-range forecasting SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEMS; LARGE-SCALE ENVIRONMENTS; NUMERICAL SIMULATIONS; EXPLOSIVE CYCLOGENESIS; PREDICTION SYSTEM; REGIONAL-ANALYSIS; INITIAL CONDITION; ETA-MODEL; PARAMETERIZATION; PRECIPITATION AB Numerical forecasts from a pilot program on short-range ensemble forecasting at the National Centers for Environmental Prediction are examined. The ensemble consists of 10 forecasts made using the 80-km Era Model and 5 forecasts from the regional spectral model. Results indicate that the accuracy of the ensemble mean is comparable to that from the 29-km Meso Eta Model for both mandatory level data and the 36-h forecast cyclone position. Calculations of spread indicate that at 36 and 48 h the spread from initial conditions created using the breeding of growing modes technique is larger than the spread from initial conditions created using different analyses. However, the accuracy of the forecast cyclone position from these two initialization techniques is nearly identical. Results further indicate that using two different numerical models assists in increasing the ensemble spread significantly. There is little correlation between the spread in the ensemble members and the accuracy of the ensemble mean for the prediction of cyclone location. Since information on forecast uncertainty is needed in many applications, and is one of the reasons to use an ensemble approach, the lack of a correlation between spread and forecast uncertainty presents a challenge to the production of short-range ensemble forecasts. Even though the ensemble dispersion is not found to be an indication of forecast uncertainty, significant spread can occur within the forecasts over a relatively short time period. Examples are shown to illustrate how small uncertainties in the model initial conditions can lead to large differences in numerical forecasts from an identical numerical model. C1 NOAA, Environm Res Lab, Natl Severe Storms Lab, Norman, OK 73069 USA. NOAA NWS Natl Ctr Environm Predict, Camp Springs, MD USA. RP Stensrud, DJ (reprint author), NOAA, Environm Res Lab, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 60 TC 128 Z9 138 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 APR PY 1999 VL 127 IS 4 BP 433 EP 446 DI 10.1175/1520-0493(1999)127<0433:UEFSRF>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 183UF UT WOS:000079571400001 ER PT J AU Kerwin, MW Overpeck, JT Webb, RS De Vernal, A Rind, DH Healy, RJ AF Kerwin, MW Overpeck, JT Webb, RS De Vernal, A Rind, DH Healy, RJ TI The role of oceanic forcing in mid-Holocene Northern Hemisphere climatic change SO PALEOCEANOGRAPHY LA English DT Article ID CANADIAN ARCTIC ARCHIPELAGO; 6 KA BP; POLLEN DATA; JULY TEMPERATURES; SEA-ICE; VEGETATION; AMERICA; SIMULATIONS; GREENLAND; MOLLUSKS AB Previous model investigations suggested that changes in orbital forcing and feedbacks associated with northward expansion of the boreal forest were both required to explain the full magnitude of enhanced high-latitude Northern Hemisphere summer warming at 6 ka, thus implying that biospheric feedbacks (decreased planetary albedo associated with forest expansion) may be large in the future [Foley ct at., 1994; TEMPO (Testing Earth System Models with Paleo-Observations), 1996]. Before the magnitude of past biospheric and other feedbacks can be estimated with confidence, however, the role of realistic high-latitude oceanic forcing (i.e., sea surface temperature (SST) increases and sea ice reductions) should also be considered. Here we review existing paleoceanographic observations that suggest portions of the North Atlantic were up to 4 degrees C warmer than today at 6 ka. We then combine our estimates of mid-Holocene North Atlantic SST and sea ice conditions with new climate model simulations to suggest that a significant portion of high-latitude summer warming at 6 ka in the Northern Hemisphere can be accounted for by altered orbital forcing, SSTs, and sea ice relative to today. Our results underscore the importance of incorporating realistic boundary conditions when using paleoenvironmental data to evaluate the climate system's sensitivity to altered forcing and suggest that high-latitude oceanic feedbacks were major contributors to enhanced high-latitude summer warming in the Northern Hemisphere at 6 ka. C1 Univ Colorado, Inst Arctic & Alpine Res, INSTAAR, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. Univ Quebec, Geotop, Res Ctr Isotope Geochem & Geochronol, Montreal, PQ H3C 3P8, Canada. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. NOAA, Paleoclimatol Program, Boulder, CO USA. RP Univ Colorado, Inst Arctic & Alpine Res, INSTAAR, Boulder, CO 80309 USA. EM kerwin@colorado.edu; jto@ngdc.noaa.gov; rsw@luna.ngdc.noaa.gov; r21024@er.uqam.ca; drind@giss.nasa.gov; rhealy@whoi.edu RI de Vernal, Anne/D-5602-2013; Healy, Richard/J-9214-2015 OI de Vernal, Anne/0000-0001-5656-724X; Healy, Richard/0000-0002-5098-8921 NR 77 TC 51 Z9 53 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0883-8305 EI 1944-9186 J9 PALEOCEANOGRAPHY JI Paleoceanography PD APR PY 1999 VL 14 IS 2 BP 200 EP 210 DI 10.1029/1998PA900011 PG 11 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA 179KD UT WOS:000079325100009 ER PT J AU Farber, L Levin, I Barsoum, MW AF Farber, L Levin, I Barsoum, MW TI High-resolution transmission electron microscopy study of a low-angle boundary in plastically deformed Ti3SiC2 SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article AB The dislocation structure of a typical low-angle boundary associated with a kink band in a sample of Ti3SiC2 deformed at room temperature was studied by high-resolution transmission electron microscopy. The boundary had both tilt and twist components. To account for both, the boundary was interpreted to be composed of parallel alternating mixed perfect dislocations with two different Burgers vectors lying in the basal plane at an angle of 120 degrees relative to one another. The boundary twist was provided by having an excess of one type of dislocation. This hitherto unreported structure of a low-angle boundary is attributed to the fact that all dislocations are confined to the basal planes. C1 Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. NIST, Div Ceram, Gaithersburg, MD 20899 USA. RP Farber, L (reprint author), Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. RI Levin, Igor/F-8588-2010 NR 7 TC 46 Z9 46 U1 0 U2 10 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD APR PY 1999 VL 79 IS 4 BP 163 EP 170 DI 10.1080/095008399177390 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 181XM UT WOS:000079468700002 ER PT J AU Rao, MVVS Van Brunt, RJ Olthoff, JK AF Rao, MVVS Van Brunt, RJ Olthoff, JK TI Kinetic-energy distributions of positive and negative ions in Townsend discharges in oxygen SO PHYSICAL REVIEW E LA English DT Article ID CHARGE-TRANSFER; REFERENCE CELL; DETACHMENT; COLLISIONS; ELECTRONS; MOLECULES; ARGON; O2 AB Translational flux-energy distributions of positive and negative ions have been measured at high electric field-to-gas density ratios (E/N) up to 40 x 10(-18) V m(2) (40 kTd) in diffuse, parallel-plate Townsend discharges in oxygen using an ion energy analyzer-mass spectrometer. The O-2(+) ion is the most abundant ion detected in the discharge, and exhibits Maxwellian energy distributions for E/N<20 x 10(18) V m(2), which is consistent with predictions based upon the assumption that resonant symmetric charge exchange is the dominant ion-molecule collision process. The less abundant ions O+, O-2(-), and O- exhibit non-Mawellian ion kinetic-energy distributions at nearly all E/N, indicative of multiple ion-molecule reactions affecting the ion transport. Mean energies are obtained for each ion as a function of E/N from an analysis of the energy distributions, and symmetric charge-exchange cross sections are calculated:from the data where appropriate. C1 Natl Inst Stand & Technol, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Rao, MVVS (reprint author), NASA, Ames Res Ctr, MS 229-1, Moffett Field, CA 94035 USA. NR 40 TC 5 Z9 5 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 APR PY 1999 VL 59 IS 4 BP 4565 EP 4572 DI 10.1103/PhysRevE.59.4565 PG 8 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 188EV UT WOS:000079834600101 ER PT J AU Konkoli, Z Johannesson, H Lee, BP AF Konkoli, Z Johannesson, H Lee, BP TI Fluctuation effects in steric reaction-diffusion systems SO PHYSICAL REVIEW E LA English DT Article ID CARBON NANOTUBES; KINETICS; DYNAMICS AB We propose a simple model for reaction-diffusion systems with orientational constraints on the reactivity of particles, and map it onto a field theory with upper critical dimension d(c)=2. To the two-loop level, long-time particle density N(t) is given by the same universal expression as for a nonsteric system, with N(t)similar to t(-d/2) for d less than or equal to 2. For slow rotations of the particles we find an intermediate regime where N(t)similar to t(-d/4), with the crossover to the nonsteric asymptotics determined by the rates of rotations and reactions. Consequences for experiments are discussed. C1 Chalmers Univ Technol, Inst Theoret Phys, S-41296 Gothenburg, Sweden. Univ Gothenburg, S-41296 Gothenburg, Sweden. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Konkoli, Z (reprint author), Chalmers Univ Technol, Inst Theoret Phys, S-41296 Gothenburg, Sweden. RI Konkoli, Zoran/D-3668-2013 OI Konkoli, Zoran/0000-0002-5468-1388 NR 23 TC 5 Z9 5 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD APR PY 1999 VL 59 IS 4 BP R3787 EP R3790 DI 10.1103/PhysRevE.59.R3787 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 188EV UT WOS:000079834600002 ER PT J AU He, J Raghavan, D Hoffman, D Hunston, D AF He, J Raghavan, D Hoffman, D Hunston, D TI The influence of elastomer concentration on toughness in dispersions containing preformed acrylic elastomeric particles in an epoxy matrix SO POLYMER LA English DT Article DE acrylic; dispersion; epoxy; fracture; morphology; preformed particles; thermoset; toughening ID RUBBER-TOUGHENED EPOXY; FRACTURE-BEHAVIOR; DEFORMATION; RESINS AB The influence of toughener concentration on the fracture behavior of two-phase, rubber-toughened epoxy is studied. To vary the concentration without altering other morphological features, samples generated from dispersions of preformed rubber (acrylic) particles in liquid epoxy monomer are used. By diluting with different amounts of epoxy prior to cure, the toughener concentration can be varied over a wide range. Thermal and microscope studies support the assertion of a constant morphology. The fracture results show that the toughness increases to a maximum and then decreases as the concentration is increased. This suggests an optimum concentration of toughening. Micrographs of the initiation zone on the fracture surface at high concentrations of rubber show less deformation than the equivalent surfaces at lower concentrations. This is consistent with a toughening mechanism based on particles initiating yielding and plastic flow in the matrix. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Howard Univ, Dept Chem, Polymer Sci Div, Washington, DC 20059 USA. Dow Chem Co, Midland, MI 48674 USA. NIST, Div Polymer, Gaithersburg, MD 20899 USA. RP Raghavan, D (reprint author), Howard Univ, Dept Chem, Polymer Sci Div, Washington, DC 20059 USA. NR 24 TC 30 Z9 33 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD APR PY 1999 VL 40 IS 8 BP 1923 EP 1933 DI 10.1016/S0032-3861(98)00436-4 PG 11 WC Polymer Science SC Polymer Science GA 158XQ UT WOS:000078143100002 ER PT J AU Vasquez, GB Ji, XH Pechik, I Fronticelli, C Gilliland, GL AF Vasquez, GB Ji, XH Pechik, I Fronticelli, C Gilliland, GL TI Oxygen binding to alpha-subunits in high-salt crystals of T-state haemoglobin SO PROTEIN AND PEPTIDE LETTERS LA English DT Article ID RECOMBINANT HUMAN HEMOGLOBIN; ESCHERICHIA-COLI; RESOLUTION; DEOXYHEMOGLOBIN; GLOBIN AB The crystal structures of a partially-oxygenated, human, T-state hemoglobin variant, beta C112G, and a deoxy structure of a related hemoglobin construct, beta(C93A+C112G), have been determined at 2.0 Angstrom and 1.8 Angstrom resolution, respectively. Oxygen molecules fully occupy the alpha(1)-heme and partially occupy the alpha(2)-heme binding sites of the beta C112G mutant hemoglobin. Comparisons of these structures with deoxy-, oxy-, and carboxyhemoglobin provide insight into hemoglobin's allosteric transition. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. Univ Maryland, Sch Med, Dept Biochem & Mol Biol, Baltimore, MD 21201 USA. RI Ji, Xinhua/C-9664-2012 OI Ji, Xinhua/0000-0001-6942-1514 NR 21 TC 0 Z9 0 U1 0 U2 0 PU BENTHAM SCIENCE PUBL BV PI HILVERSUM PA PO BOX 1673, 1200 BR HILVERSUM, NETHERLANDS SN 0929-8665 J9 PROTEIN PEPTIDE LETT JI Protein Pept. Lett. PD APR PY 1999 VL 6 IS 2 BP 59 EP 66 PG 8 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 192YU UT WOS:000080108000001 ER PT J AU Xiao, GY Tordova, M Jagadeesh, J Drohat, AC Stivers, JT Gilliland, GL AF Xiao, GY Tordova, M Jagadeesh, J Drohat, AC Stivers, JT Gilliland, GL TI Crystal structure of Escherichia coli uracil DNA glycosylase and its complexes with uracil and glycerol: Structure and glycosylase mechanism revisited SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE E-coli uracil DNA glycosylase; uracil complex; glycosylase mechanism; acid-base catalysis ID REPAIR PROTEIN; EXCISION; PHOSPHORIBOSYLTRANSFERASE AB The DNA repair enzyme uracil DNA glycosylase (UDG) catalyzes the hydrolysis of premutagenic uracil residues from single-stranded or duplex DNA, producing free uracil and abasic DNA. Here we report the high-resolution crystal structures of free UDC; from Escherichia coli strain B (1.60 Angstrom), its complex with uracil (1.50 Angstrom), and a second active-site complex with glycerol (1.43 Angstrom). These represent the first high-resolution structures of a prokaryotic UDG to be reported. The overall structure of the E, coli enzyme is more similar to the human UDG than the herpes virus enzyme, Significant differences between the bacterial and viral structures are seen in the side-chain positions of the putative general-acid (His187) and base (Asp64), similar to differences previously observed between the viral and human enzymes. In general, the active-site loop that contains His187 appears preorganized in comparison with the viral and human enzymes, requiring smaller substrate-induced conformational changes to bring active-site groups into catalytic position. These structural differences may be related to the large differences in the mechanism of uracil recognition used by the E, coli and viral enzymes. The pH dependence of k(cat) for wild-type UDG and the D64N and H187Q mutant enzymes is consistent with general-base catalysis by Asp64, but provides no evidence for a general-acid catalyst. The catalytic mechanism of UDG is critically discussed with respect to these results. Proteins 1999;35:13-24. (C) 1999 Wiley-Liss, Inc. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD USA. RP Gilliland, GL (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. EM gary.gilliland@carb.nist.gov RI ID, IMCACAT/D-5867-2014 FU NIGMS NIH HHS [GM56834, R01 GM056834] NR 35 TC 86 Z9 88 U1 0 U2 1 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD APR 1 PY 1999 VL 35 IS 1 BP 13 EP 24 PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 173NZ UT WOS:000078987800002 PM 10090282 ER PT J AU Shull, JM Penton, SV Stocke, JT AF Shull, JM Penton, SV Stocke, JT TI The low-redshift intergalactic medium SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF AUSTRALIA LA English DT Article; Proceedings Paper CT Workshop on HI in the Local Universe II CY SEP 28-30, 1998 CL UNIV MELBOURNE, MELBOURNE, AUSTRALIA SP Australia Telescope Natl Facil, Univ Western Australia, Univ Melbourne HO UNIV MELBOURNE DE intergalactic medium; quasars : absorption lines ID LYMAN-ALPHA ABSORPTION; GALAXIES; ORIGIN; CLOUDS AB The low-redshift Ly alpha forest of absorption lines provides a probe of large-scale baryonic structures in the intergalactic medium, some of which may be remnants of physical conditions set up during the epoch of galaxy formation. We discuss our recent Nubble Space Telescope (HST) observations and interpretation of low-z Ly alpha clouds toward nearby Seyferts and QSOs, including their frequency, space density, estimated mass, association with galaxies, and contribution to Omega(b). Our HST/GHRS detections of similar to 70 Ly alpha absorbers with N-HI greater than or equal to 10(12.6) cm(-2) along 11 sightlines covering pathlength Delta(cz) = 114,000 km s(-1) show f(>N-HI) proportional to N-HI(-0.63+/-0.04) and a line frequency dN/dz = 200 +/- 40 for N-HI > 10(12.6) cm(-2) (one every 1500 km s(-1) of redshift). A group of strong absorbers toward PKS 2155-304 may be associated with gas (400 - 800)h(75)(-1) kpc from four large galaxies, with low metallicity (less than or equal to 0.003 solar) and D/H less than or equal to 2 x 10(-4). At low-z, we derive a metagalactic ionising radiation field from AGN of J(0) = 1.3(-0.5)(+0.8) x 10(-23) erg cm(-2) s(-1) Hz(-1) sr(-1) and a Ly alpha-forest baryon density Omega(b) = (0.008 +/- 0.004)h(75)(-1) [J(-23)N(14)b(100)](1/2) for clouds of characteristic size b = (100 kpc)b(100). C1 Univ Colorado, Dept Astrophys & Planetary Sci, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. RP Shull, JM (reprint author), Univ Colorado, Dept Astrophys & Planetary Sci, Ctr Astrophys & Space Astron, CB-389, Boulder, CO 80309 USA. NR 24 TC 13 Z9 13 U1 0 U2 0 PU C S I R O PUBLISHING PI COLLINGWOOD PA 150 OXFORD ST, PO BOX 1139, COLLINGWOOD, VICTORIA 3066, AUSTRALIA SN 1323-3580 J9 PUBL ASTRON SOC AUST JI Publ. Astron. Soc. Aust. PD APR PY 1999 VL 16 IS 1 BP 95 EP 99 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 208AC UT WOS:000080967200019 ER PT J AU Shimada, Y Kondo, Y Inokoshi, S Tagami, J Antonucci, JM AF Shimada, Y Kondo, Y Inokoshi, S Tagami, J Antonucci, JM TI Demineralizing effect of dental cements on human dentin SO QUINTESSENCE INTERNATIONAL LA English DT Article DE confocal laser scanning microscopy; demineralization; dentin; glass-ionomer cement; scanning electron microscopy; zinc phosphate cement; zinc polycarboxylate cement ID GLASS-IONOMER CEMENTS; ADHESIVE INTERFACE; PULPAL RESPONSE; RESIN; MICROSCOPY; PERMEABILITY; LESIONS; SYSTEMS; REMOVAL; INVIVO AB Objective: This study was undertaken to verify the hypothesis that dentin surfaces are demineralized during placement of four kinds of chemically setting cements (zinc phosphate cement, luting glass-ionomer cement, restorative glass-ionomer cement, and zinc polycarboxylate cement). Method and materials: Sixty cemented dentin disks were observed under scanning electron microscopy and with confocal laser scanning microscopy after use of an argon-ion etching technique. To determine the surface effects of the cements, 30 dentin surfaces were treated with 1 of 6 freshly mixed cements (5 per group) for 60 seconds. The disks were subjected to rinsing with a wafer spray and ultrasonic washing prior to scanning electron microscopic observation. Results: Observation of cemented dentin specimens revealed that the dentin was not completely demineralized at the interface formed by the cement and dentin and that the extent and depth of demineralization along the interface tended to be nonuniform. Zinc phosphate cement caused the greatest demineralization of dentin, followed by luting glass-ionomer cement. The extent of demineralization with restorative glass-ionomer cement or zinc polycarboxylate cement was less discernible. Confocal laser scanning microscopy generally confirmed scanning electron microscopic observations and revealed that most of the specimens showed close adaptation of the cements to the dentin surfaces. Conclusion: Acid-containing cements have self-etching properties that are effective, to various degrees, in removing the smear layer and promoting close adaptation to dentin surfaces. C1 Tokyo Med & Dent Univ, Fac Dent, Dept Operat Dent, Bunkyo Ku, Tokyo 113, Japan. Natl Inst Stand & Technol, Dent & Med Mat Grp, Div Polymers, Gaithersburg, MD 20899 USA. RP Shimada, Y (reprint author), Tokyo Med & Dent Univ, Fac Dent, Dept Operat Dent, Bunkyo Ku, 1-5-45 Yushima, Tokyo 113, Japan. NR 35 TC 24 Z9 24 U1 0 U2 0 PU QUINTESSENCE PUBL CO INC PI CAROL STREAM PA 551 NORTH KIMBERLY DR, CAROL STREAM, IL 60188-1881 USA SN 0033-6572 J9 QUINTESSENCE INT JI Quintessence Int. PD APR PY 1999 VL 30 IS 4 BP 267 EP 273 PG 7 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 190MV UT WOS:000079968300012 PM 10635255 ER PT J AU Woodruff, DL Stumpf, RP Scope, JA Paerl, HW AF Woodruff, DL Stumpf, RP Scope, JA Paerl, HW TI Remote estimation of water clarity in optically complex estuarine waters SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID MODERATELY TURBID ESTUARY; DISSOLVED ORGANIC-MATTER; NEUSE RIVER ESTUARY; ATTENUATION COEFFICIENT; NORTH-CAROLINA; OCEANIC WATERS; PHYTOPLANKTON; ABSORPTION; REFLECTANCE; QUALITY AB AVHRR satellite imagery was evaluated as a potential data source for monitoring light attenuation (K-PAR), as a measure of turbidity, in Pamlico Sound estuary, North Carolina. In situ water quality data and reflectance imagery collected on 10 different dates were used to calibrate a general optical equation relating satellite-derived reflectance (R-d), nominally R-(630 nm) to K-PAR. Additional spectral data (e.g., absorption, subsurface reflectance), related reflectance and K-PAR to changes in phytoplankton pigments, organic matter, and suspended sediments. Optically, Pamlico Sound, North Carolina is dominated by scattering from suspended sediments, whereas the tributary rivers are dominated by absorption from both dissolved and particulate organic matter. A general relationship developed between R-d and K-PAR (r(2)=0.72) in Pamlico Sound was found useful in a variety of environmental conditions; however a relationship between R-d and suspended sediment concentration was less robust, and affected by changing sediment characteristics. In the rivers, high and variable absorption in the visible wavelengths precluded development of a relationship between R-d and K-PAR. The relationship developed between R-d and K-PAR in Pamlico Sound is similar to those determined for Delaware Bay and Mobile Bay in previous studies, suggesting possible broader regional application of algorithms for coastal bays and estuaries having similar sediment characteristics, with direct application to SeaWiFS data. Published by Elsevier Science Inc. C1 NOAA, Natl Marine Fisheries Serv, Beaufort, NC USA. US Geol Survey, Ctr Coastal Geol, St Petersburg, FL USA. Univ N Carolina, Inst Marine Sci, Morehead City, NC 28557 USA. RP Woodruff, DL (reprint author), Battelle Marine Sci Lab, 1529 W Sequim Bay Rd, Sequim, WA 98382 USA. EM dana.woodruff@pnl.gov NR 49 TC 49 Z9 52 U1 2 U2 6 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 APR PY 1999 VL 68 IS 1 BP 41 EP 52 DI 10.1016/S0034-4257(98)00108-4 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 178KG UT WOS:000079264400004 ER PT J AU Elvidge, CD Baugh, KE Dietz, JB Bland, T Sutton, PC Kroehl, HW AF Elvidge, CD Baugh, KE Dietz, JB Bland, T Sutton, PC Kroehl, HW TI Radiance calibration of DMSP-OLS low-light imaging data of human settlements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID CITY LIGHTS; UNITED-STATES; SATELLITE; POPULATION; EMISSIONS; IMAGERY; EARTH AB Nocturnal lighting is a primary method for enabling human activity. Outdoor lighting is used extensively world-wide in residential, commercial, industrial, public facilities, and roadways. A radiance calibrated nighttime lights image of the United States has been assembled from Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). The satellite observation of the location and intensity of nocturnal lighting provide a unique view of humanities presence and can be used as a spatial indicator for other variables that are more difficult to observe at a global scale. Examples include the modeling of population density and energy related greenhouse gas emissions. Published by Elsevier Science Inc. C1 NOAA, Solar Terr Phys Div, Natl Geophys Data Ctr, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. Northrop Grumman Corp, Elect Sensors & Syst Div, Baltimore, MD USA. Univ Calif Santa Barbara, Dept Geog, Santa Barbara, CA 93106 USA. RP Elvidge, CD (reprint author), NOAA, Solar Terr Phys Div, Natl Geophys Data Ctr, 325 Broadway, Boulder, CO 80303 USA. EM cde@ngdc.noaa.gov RI Elvidge, Christopher/C-3012-2009; Sutton, Paul/A-6764-2013 OI Sutton, Paul/0000-0001-6972-3256 NR 20 TC 186 Z9 198 U1 5 U2 67 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 APR PY 1999 VL 68 IS 1 BP 77 EP 88 DI 10.1016/S0034-4257(98)00098-4 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 178KG UT WOS:000079264400007 ER PT J AU Dhez, P Chevallier, P Lucatorto, TB Tarrio, C AF Dhez, P Chevallier, P Lucatorto, TB Tarrio, C TI Instrumental aspects of x-ray microbeams in the range above 1 keV SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Review ID BRAGG-FRESNEL LENS; SYNCHROTRON-RADIATION; ZONE PLATES; SPATIAL-RESOLUTION; GRAZING-INCIDENCE; EXTREME-ULTRAVIOLET; MULTILAYER MIRRORS; WAVE-GUIDE; OPTICS; DIFFRACTION AB X-ray microscopy has the capability of looking into normally opaque samples with high resolution. X rays are sensitive to elemental, structural, and chemical content and thus can provide microscopic maps of the composition and structure of a sample. X-ray microscopy has seen great growth in the last two decades in the number and types of operating instruments as well as their capabilities. This growth is due to two developments. The first is the development of high-brightness second- and third-generation synchrotron light sources that can be used with small-aperture optics. The second is a revolution in x-ray optics. In addition to the extension of commonly used visible optics, such as Fresnel zone plates and multilayer mirrors, into the x-ray regime, there has also been a dramatic improvement in grazing-incidence optics fabrication. In the range up to a few keV, Fresnel zone plates offer the highest resolution, which is below 100 nm in several instruments. Recent developments in fabrication may lead to their application at higher energies; for now, however, sub-mu m diffractive microfocusing at higher energies is usually achieved by Bragg-Fresnel optics, Fresnel optics operated in reflection using either crystal planes or multilayer coatings. Although these offer very high resolution, they have small collection apertures and limited wavelength range of operation. The Kirkpatrick-Baez mirror combination remains the most popular and versatile microprobe in the x-ray regime. These systems can operate over a very broad energy range and several facilities are now operating with micron-scale resolution. We will discuss these and some newer types of x-ray focusing schemes. (C) 1999 American Institute of Physics. [S0034-6748(99)01304-0]. C1 Univ Paris 11, LSAI, F-91405 Orsay, France. LURE, F-91405 Orsay, France. Univ Paris 06, LPAN, F-75252 Paris, France. LURE, F-75252 Paris, France. Natl Inst Stand & Technol, Photon Phys Grp, Gaithersburg, MD 20899 USA. RP Dhez, P (reprint author), Univ Paris 11, LSAI, Bat 425, F-91405 Orsay, France. NR 147 TC 37 Z9 40 U1 1 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 1999 VL 70 IS 4 BP 1907 EP 1920 DI 10.1063/1.1149733 PG 14 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184QM UT WOS:000079624500001 ER PT J AU DeMarco, B Rohner, H Jin, DS AF DeMarco, B Rohner, H Jin, DS TI An enriched K-40 source for fermionic atom studies SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID POTASSIUM ATOMS AB We have developed a novel, enriched potassium source for use in trapping and cooling of the fermionic isotope K-40. The source is clean, easily controllable, and consistent with high vacuum applications. With this enriched source, we are able to collect 10(8) K-40 atoms in a vapor cell magneto-optical trap. (C) 1999 American Institute of Physics. [S0034-6748(99)00304-4]. C1 Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO USA. RP DeMarco, B (reprint author), Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. OI DeMarco, Brian/0000-0002-2791-0413 NR 8 TC 22 Z9 22 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 1999 VL 70 IS 4 BP 1967 EP 1969 DI 10.1063/1.1149695 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184QM UT WOS:000079624500008 ER PT J AU Potzick, J AF Potzick, J TI Noise averaging and measurement resolution (or "A little noise is a good thing") SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB When a continuous quantity is measured with a digital instrument or digitized for further processing, a measurement uncertainty component is incurred from quantization of the continuous variable. This uncertainty can be reduced by oversampling and averaging multiple measurements, but only if there is some noise on the measurand. In this article the optimum noise level is determined, and the subsequent improvement in measurement uncertainty calculated. [S0034-6748(99)04604-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Potzick, J (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 4 TC 11 Z9 11 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 1999 VL 70 IS 4 BP 2038 EP 2040 DI 10.1063/1.1149735 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184QM UT WOS:000079624500020 ER PT J AU Suenram, RD Grabow, JU Zuban, A Leonov, I AF Suenram, RD Grabow, JU Zuban, A Leonov, I TI A portable, pulsed-molecular-beam, Fourier-transform microwave spectrometer designed for chemical analysis SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID NOZZLE; COMPLEXES AB M. D. Harmony, K. A. Beran, D. M. Angst, and K. L. Ratzlaff [Rev. Sci. Instrum. 66, 5196 (1995)] recently published some design specifications for a smaller version of a Fourier transform microwave (FTMW) spectrometer. In that work they used a nozzle arrangement which pulsed the molecular beam perpendicular to the axis of the Fabry-Perot cavity. They found that even though the size of the vacuum chamber and Fabry-Perot cavity mirrors had been reduced, the overall sensitivity of the instrument was nearly the same as one with a conventional sized resonator. In an effort to establish FTMW spectroscopy as a viable new technique for analytical chemists, we have constructed a miniaturized version of our laboratory instrument for use as an analytical instrument. The vacuum chamber of the instrument is based on a commercially available, multiport 30 cm (12 in. ! sphere. An integral end-flange mirror permits a coaxial nozzle injection of the molecular beam which greatly improves the sensitivity of the instrument. The movable cavity mirror rides on a fast motorized stage which allows tuning to any frequency within the range of the spectrometer in 1-2 s. The entire spectrometer is mounted on a mobile cart, allowing it to be easily transported to other laboratories or remote locations. The per-pulse sensitivity of this smaller instrument is slightly less than the larger laboratory instruments, however the smaller vacuum chamber allows the nozzle to be pulsed much faster without overloading the vacuum pumps. The new miniaturized FTMW spectrometer is only a factor of 2 less sensitive than the larger laboratory instrument. This instrument provides analytical chemists with a new tool that can unambiguously identify trace amounts of large organic compounds in gas streams. The instrument also permits real-time analysis which should be useful for monitoring and optimization of process gas streams. Lower detection limits are typically in the nanomol/mol regime. (C) 1999 American Institute of Physics. [S0034-6748(99)01204-6]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Inst Phys & Elektrochem, D-30167 Hannover, Germany. Russian Acad Sci, Inst Appl Phys, Nizhnii Novgorod 603600, Russia. RP Suenram, RD (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 18 TC 119 Z9 119 U1 3 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 1999 VL 70 IS 4 BP 2127 EP 2135 DI 10.1063/1.1149725 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 184QM UT WOS:000079624500039 ER PT J AU Boutin, J Etcheto, J Dandonneau, Y Bakker, DCE Feely, RA Inoue, HY Ishii, M Ling, RD Nightingale, PD Metzl, N Wanninkhof, R AF Boutin, J Etcheto, J Dandonneau, Y Bakker, DCE Feely, RA Inoue, HY Ishii, M Ling, RD Nightingale, PD Metzl, N Wanninkhof, R TI Satellite sea surface temperature: a powerful tool for interpreting in situ pCO(2) measurements in the equatorial Pacific Ocean SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID JANUARY-MARCH 1991; PARTIAL-PRESSURE; CO2 FLUXES; EL-NINO; CARBON-DIOXIDE; WIND SPEEDS; WARM POOL; DISTRIBUTIONS; SEAWATER; ATLANTIC AB In order to determine the seasonal and interannual variability of the CO(2) released to the atmosphere from the equatorial Pacific, we have developed pCO(2)-temperature relationships based upon shipboard oceanic CO(2) partial pressure measurements, pCO(2), and satellite sea surface temperature, SST, measurements. We interpret the spatial variability in pCO(2) with the help of the SST imagery. In the eastern equatorial Pacific, at 5 degrees S, pCO(2) variations of up to 100 mu atm are caused by undulations in the southern boundary of the equatorial upwelled waters. These undulations appear to be periodic with a phase and a wavelength comparable to tropical instability waves, TIW, observed at the northern boundary of the equatorial upwelling. Once the pCO(2) signature of the TIW is removed from the Alize II cruise measurements in January 1991, the equatorial pCO(2) data exhibit a diel cycle of about 10 mu atm with maximum values occurring at night. In the western equatorial Pacific the variability in pCO(2) is primarily governed by the displacement of the boundary between warm pool waters, where air-sea CO(2) fluxes are weak, and equatorial upwelled waters which release high CO(2) fluxes to the atmosphere. We detect this boundary using satellite SST maps. East of the warm pool, Delta P is related to SST and SST anomalies. The 1985-1997 CO(2) flux is computed in a 5 degrees wide latitudinal band as a combination of Delta P and CO(2) exchange coefficient, K, deduced from satellite wind speeds, U. It exhibits up to a factor 2 seasonal variation caused by K-seasonal variation and a large interannual variability, a factor 5 variation between 1987 and 1988. The interannual variability is primarily driven by displacements of the warm pool that makes the surface area of the outgassing region variable The contribution of Delta P to the flux variability is about half the contribution of K. The mean CO(2) flux computed using either the Liss and Merlivat (1986) or the Wanninkhof (1992) K-U parametrization amounts to 0.11 GtC yr(-1) or to 0.18 GtC yr(-1), respectively. The error in the integrated flux, without taking into account the uncertainty on the K-U parametrization, is less than 31%. C1 CNRS ORSTOM UPMC, LODYC, UMR 121, Paris, France. NOAA PMEL, Seattle, WA USA. Meteorol Res Inst, Geochem Lab, Tsukuba, Ibaraki 305, Japan. Plymouth Marine Lab, Plymouth, Devon, England. CNRS UPMC, LPCM, Paris, France. NOAA AOML, Miami, FL USA. RP Boutin, J (reprint author), CNRS ORSTOM UPMC, LODYC, UMR 121, Paris, France. EM jb@lodyc.jussieu.fr RI Yoshikawa, Hisayuki/A-4056-2012; Nightingale, Philip/I-4324-2012; Bakker, Dorothee/E-4951-2015; Boutin, Jacqueline/M-2253-2016 OI Yoshikawa, Hisayuki/0000-0002-9936-2188; Nightingale, Philip/0000-0001-7177-5469; Bakker, Dorothee/0000-0001-9234-5337; NR 50 TC 41 Z9 44 U1 0 U2 7 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 1999 VL 51 IS 2 BP 490 EP 508 DI 10.1034/j.1600-0889.1999.00025.x PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400025 ER PT J AU Wanninkhof, R Doney, SC Peng, TH Bullister, JL Lee, K Feely, RA AF Wanninkhof, R Doney, SC Peng, TH Bullister, JL Lee, K Feely, RA TI Comparison of methods to determine the anthropogenic CO2 invasion into the Atlantic Ocean SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID EASTERN NORTH-ATLANTIC; CARBON-DIOXIDE SYSTEM; ISOPYCNAL SURFACES; REDFIELD RATIOS; WORLD OCEAN; MODEL; CIRCULATION; SECTION; INCREASE; TRACER AB A comparison of different methods for estimating the anthropogenic CO2 burden in the Atlantic Ocean is performed using referenced, high quality total dissolved inorganic carbon (DIC) data. The dataset is from two cruises through the center of the basin between 62 degrees N and 43 degrees S in 1991 and 1993. The specific anthropogenic input is determined utilizing empirical procedures as described in Gruber et al. (1996) and Chen and Millero (1979) to correct for remineralization and to estimate preanthropogenic endmembers. These estimates are compared with output of the Princeton ocean biogeochemical model and the NCAR ocean model. The results show that the specific inventories of anthropogenic carbon agree to within 20% but with different storage and uptake patterns. The empirical estimates differ because of assumptions about mixing and winter outcrop endmembers. The same remineralization quotients (Redfield ratios) were used for each method. Varying these constants within the range of literature values causes changes in specific inventories of similar magnitude as the differences observed with different methodologies. Comparison of anthropogenic CO2 uptake and chlorofluorocarbon ages suggests that the anthropogenic CO2 penetration in the North Atlantic is too shallow following the procedure according to Gruber et al. (1996), and too deep using those of Chen and Millero (1979). The results support these previous observations in that the uptake of CO2 in the North Atlantic is disproportionate to its surface area. This is caused by a combination of deep water formation and deep winter mixed layers. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Miami, Cooperat Inst Marine & Atmospher Sci, Miami, FL 33149 USA. RP Wanninkhof, R (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Doney, Scott/F-9247-2010; Lee, Kitack/G-7184-2015 OI Doney, Scott/0000-0002-3683-2437; NR 49 TC 52 Z9 54 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 1999 VL 51 IS 2 BP 511 EP 530 DI 10.1034/j.1600-0889.1999.00027.x PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400027 ER PT J AU Peng, TH Hung, JJ Wanninkhof, R Millero, FJ AF Peng, TH Hung, JJ Wanninkhof, R Millero, FJ TI Carbon budget in the East China Sea in spring SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID CHEMICAL HYDROGRAPHY; NORTH; DYNAMICS; SEAWATER; TAIWAN AB Results of total dissolved inorganic carbon (DIC) and total alkalinity (TA) measurements made in the East China Sea (ECS) during a geochemical expedition of KEEP (Kuroshio Edge Exchange Processes) program in May of 1996 show that ECS is a CO2 sink during the spring season. The mean difference of fCO(2) (fugacity of CO2) between the atmosphere and surface water is calculated to be 28 mu atm, and the resulting net CO2 invasion flux is 2.1 mol m(-2) yr(-1), which gives about 0.03 GtC/yr of CO2 uptake in this continental shelf in spring. This study supports the notion that the shelf regions can be a significant CO2 sink. The riverine alkalinity, which discharges into ECS, is estimated to be 1,743 mu mol kg(-1) on the basis of a linear relationship between TA and salinity. The observed salinity-normalized alkalinity in ECS is higher than that in the open sea, and this excess alkalinity is estimated to be 42 mu mol kg(-1). With the known rate of the Changjiang discharge, this excess TA gives a mean residence time of 1.2 years for the continental shelf water in the ECS. The DIC in the ECS is also found to be higher than that in the open sea. This excess DIC is estimated to be about 76 +/- 70 mu mol kg(-1), which is equal to a net carbon input to ECS of 3.9 +/- 3.6 mol m(-2) yr(-1). Based on the riverine alkalinity input, the equivalent riverine carbon flux from Changjiang discharge is estimated to be about 1.8 mol m(-2) yr(-1). With net CO2 invasion flux of 2.1 +/- 2.8 mol m(-2) yr(-1), the remaining 0 +/- 4.6 mol m(-2) yr(-1) could come from remineralization of organic matter derived from biological pump in the shelf or terrestrial sources. Although this preliminary carbon budget implies that gas exchange and riverine input are the main sources of excess carbon in ECS, the contribution of biological carbon flux can not be ruled out because of the large uncertainty associated with these estimates. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. NSYSU, Inst Marine Geol & Chem, Kaohsiung, Taiwan. Univ Miami, MAC RSMAS, Miami, FL 33149 USA. RP Peng, TH (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. OI Hung, Jia-Jang/0000-0003-3432-2107 NR 21 TC 42 Z9 47 U1 2 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 1999 VL 51 IS 2 BP 531 EP 540 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400028 ER PT J AU Sarmiento, JL Hughes, TMC AF Sarmiento, JL Hughes, TMC TI Anthropogenic CO2 uptake in a warming ocean SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID MODEL C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Sarmiento, JL (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, POB CN710, Princeton, NJ 08544 USA. NR 7 TC 11 Z9 11 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 1999 VL 51 IS 2 BP 560 EP 561 DI 10.1034/j.1600-0889.1999.00030.x PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400030 ER PT J AU Tans, PP Wallace, DWR AF Tans, PP Wallace, DWR TI Carbon cycle research after Kyoto SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID ATMOSPHERIC CO2; ATLANTIC-OCEAN; THERMOHALINE CIRCULATION; 3-DIMENSIONAL SYNTHESIS; ANTHROPOGENIC CO2; DIOXIDE; TRANSPORT; FOREST; MODEL; FLUXES AB Recent progress in research of the global carbon cycle is reviewed and research needs for the immediate future are discussed, in light of the challenge posed to society to come to grips with the problem of man-made climate change. The carbon cycle in the oceans and on the land is reviewed, and how the atmosphere functions to couple them together. Major uncertainties still exist for any projection of the future atmospheric burden of carbon dioxide resulting from postulated emission scenarios of CO2. We present some ideas on how future policies designed to limit emissions or to sequester carbon can possibly be supported by scientific evidence of their effectiveness. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80304 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. RP Tans, PP (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Mailcode R-E-CG1,325 Broadway, Boulder, CO 80304 USA. NR 49 TC 12 Z9 18 U1 1 U2 4 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 1999 VL 51 IS 2 BP 562 EP 571 DI 10.1034/j.1600-0889.1999.00031.x PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211CY UT WOS:000081143400031 ER PT J AU Chou, YK Evans, CJ AF Chou, YK Evans, CJ TI Cubic boron nitride tool wear in interrupted hard cutting SO WEAR LA English DT Article; Proceedings Paper CT 12th International Conference on Wear of Materials CY APR 25-29, 1999 CL ATLANTA, GA DE cubic boron nitride tool wear; M50 steel; CBN-H; CBN-L AB Cubic boron nitride (CBN) tool wear in interrupted turning of hardened M50 steel has been investigated. The goal was to identify the dominant wear mechanism during interrupted cutting, and in particular, to study the effect of CBN content. Results show significantly different wear characteristics between high (CBN-H) and low (CBN-L) CBN content tools. Contrary to Taylor's tool life equation, tool life of CBN-L is optimized at a medium cutting speed. In contrast, CBN-H shows a monotonic decrease of tool life with increasing cutting speed. Moreover, CBN-H is less sensitive to interrupted cutting than CBN-L, which shows consistent decrease of tool life with increasing frequency of interruption. It is suggested that the higher hardness and fracture toughness of CBN-H result in greater resistance to mechanical wear that becomes more dominant in interrupted cutting. However, the metallic binder in CBN-H has high affinity with workpiece materials and, therefore, results in rapid thermally activated wear at high cutting speeds. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Chou, YK (reprint author), Univ Missouri, Dept Mech Engn, 5605 Troost Ave, Kansas City, MO 64110 USA. EM chouy@umkc.edu NR 16 TC 53 Z9 55 U1 1 U2 5 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD APR PY 1999 VL 225 BP 234 EP 245 DI 10.1016/S0043-1648(99)00012-5 PN 1 PG 12 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 190EM UT WOS:000079949200029 ER PT J AU Hwang, TW Evans, CJ Malkin, S AF Hwang, TW Evans, CJ Malkin, S TI Size effect for specific energy in grinding of silicon nitride SO WEAR LA English DT Article; Proceedings Paper CT 12th International Conference on Wear of Materials CY APR 25-29, 1999 CL ATLANTA, GA DE grinding; silicon nitride; size effect ID MECHANISMS; WEAR AB An investigation is reported of the 'size effect' for specific energy in grinding of silicon nitride. Experimental measurements over a wide range of operating parameters using two different grit size diamond wheels show an increase in specific energy as the grit depth of cut (uncut chip thickness) is reduced. An attempt was made to account for these results by modifying an upper bound plowing model, which shows an increase in specific energy with a pyramidal tool as its semi-included angle increases. Fitting the measured specific energy to the upper bound model leads to a triangular grit cross-sectional cutting profile rounded at its tip, which can be characterized in terms of an average tip radius and semi-included angle. A plot of dimensionless specific grinding energy (specific energy divided by workpiece hardness) vs. dimensionless depth of cut (depth of cut divided by tip radius) yields a single inverse linear relationship whereby the dimensionless specific grinding energy increases steeply as the dimensionless grit depth of cut decreases below about 0.5. This would indicate that the 'grit size effect' is mainly due to rounding at the abrasive cutting points. (C) 1999 Published by Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Mfg Engn Lab, Gaithersburg, MD 20899 USA. Univ Massachusetts, Dept Mech & Ind Engn, Amherst, MA 01003 USA. RP Hwang, TW (reprint author), Natl Inst Stand & Technol, Mfg Engn Lab, Gaithersburg, MD 20899 USA. EM taewook.hwang@nist.gov NR 17 TC 37 Z9 38 U1 4 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0043-1648 J9 WEAR JI Wear PD APR PY 1999 VL 225 BP 862 EP 867 DI 10.1016/S0043-1648(98)00406-2 PN 2 PG 6 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 190EN UT WOS:000079949300025 ER PT J AU Mao, Q McNider, RT Mueller, SF Juang, HMH AF Mao, Q McNider, RT Mueller, SF Juang, HMH TI An optimal model output calibration algorithm suitable for objective temperature forecasting SO WEATHER AND FORECASTING LA English DT Article ID REGIONAL SPECTRAL MODEL; MAXIMUM TEMPERATURES; LINEAR-REGRESSION; PRECIPITATION; PREDICTION; CONTEST AB An optimal model output calibration (MOC) algorithm suitable for surface air temperature forecasts is proposed and tested with the National Centers for Environmental Prediction Regional Spectral Model (RSM). Differing from existing methodologies and the traditional model output statistics (MOS) technique, the MOC algorithm uses forecasts and observations of the most recent 2-4 weeks to objectively estimate:and adjust the current model forecast errors and make refined predictions. The MOC equation, a multivariate linear regression equation with forecast error being the predictand, objectively screens as many as 30 candidates of predictors and optimally selects no more than 6. The equation varies from day to day and from site to: site. Since it does not rely on long-term statistics of stable model runs, the MOC minimizes the influence of changes in model physics and spatial resolution on the forecast refinement process. Forecast experiments were conducted for six major urban centers in the Tennessee Valley over the period of 27 June to 30:July 1997. Surface air temperature forecasts out to 72 h were produced based upon RSM runs initialized from 0000 UTC observations. Performance of the MOC for minimum and maximum temperature forecasts was assessed by determining mean forecast error (BIAS). mean absolute error (MAE), and root-mean-square errors (rmse) for both the MOC-adjusted and nonadjusted RSM output. The same statistical measures for Nested Grid Model-MOS forecasts over the experiment period-were also provided for instruction. A skill score was calculated to demonstrate the improvement of refined forecasts with the MOC over the RSM. On average for the six sites, reduction of forecast errors by the MOC ranged from 58% to 98% in BIAS, 40% to 52% in MAE, and 33% to 46% in rmse. It also showed that the error frequencies of the refined forecasts had Gaussian distributions with the peak centered around zero. The error bands were narrower: using the MOC and there Were decreases in large forecast errors, especially during the first 48 h, The Wilcoxon signed-rank lest was performed to verify that populations of the forecast errors before and after the MOC adjustment were statistically far enough apart to be distinct at a high significance level. Forecast experiments were also conducted to address the issue of sensitivity of the MOC by varying the length of the time series used in deriving the MOC equation. It was found that the mean biases of the refined forecasts slightly increased and the MAE and rmse slightly decreased with increasing length of the time series from 2 to 4 weeks. The study demonstrated the usefulness of the MOC for objective temperature forecasting: especially in an operational environment in which changes in model physics and configurations are continually implemented and no long-term stable model runs are readily available to generate MOS forecast guidance. The MOC is also informative for diagnosing and tuning model physics. The study suggests that the MOC may be applied to other weather forecast elements, such as precipitation, Cloud cover, visibility, and wind speed and direction. C1 Univ Alabama, ESSL, Huntsville, AL 35806 USA. Tennessee Valley Author, Muscle Shoals, AL 35660 USA. Natl Ctr Environm Predict, Washington, DC USA. RP Mao, Q (reprint author), Univ Alabama, ESSL, 977 Explorer Blvd, Huntsville, AL 35806 USA. NR 31 TC 19 Z9 21 U1 0 U2 3 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 1999 VL 14 IS 2 BP 190 EP 202 DI 10.1175/1520-0434(1999)014<0190:AOMOCA>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187XH UT WOS:000079813400004 ER PT J AU Nicosia, DJ Ostuno, EJ Winstead, N Klavun, G Paterson, C Gilbert, C Bryan, G Clark, JHE Fritsch, JM AF Nicosia, DJ Ostuno, EJ Winstead, N Klavun, G Paterson, C Gilbert, C Bryan, G Clark, JHE Fritsch, JM TI A flash flood from a lake-enhanced rainband SO WEATHER AND FORECASTING LA English DT Article ID BOUNDARY-LAYER; MODEL; EXAMPLES; FEATURES AB An analysis of a flash flood caused by a lake-enhanced rainband is presented. The flood took place near Erie, Pennsylvania, on 17 September 1996. It was found that the hood resulted from a complex interplay of several scales of forcing that converged over the Erie region. In particular, the flood occurred during a period when 1) a lake-enhanced convective rainband pivoted over the city of Erie with the pivot point remaining quasi-stationary for about 5 h; 2) a deep, surface-based no-shear layer, favorable for the development of strong lake-induced precipitation bands, passed over the eastern portion of Lake Erie; 3) the direction of flow in the no-shear layer shifted from shore parallel to onshore at an angle that maximized frictional convergence; 4) an upper-level short-wave trough contributed to low-level convergence, lifting, and regional destabilization; and 5) a strong land-lake diurnal temperature difference produced a lake-scale disturbance that locally enhanced the low-level convergence. Analysis of the Weather Surveillance Radar-1988 Doppler radar data from Buffalo, New York, and Cleveland, Ohio, revealed that most of the radar-derived precipitation estimates for the region were overdone except for the region affected by the quasi-stationary rainband, which was underestimated. Reconstruction of the conditions in the vicinity of the band indicate that cloud bases were considerably lower and equivalent potential temperatures higher than for the areas of precipitation farther east over northwestern Pennsylvania and southwestern New York State. It is postulated that, due to the long distance from the radar sites to the Erie area, the radar was unable to observe large amounts of cloud condensate produced by warm-rain processes below 4 km. Estimates of precipitation rates from a simple cloud model support this interpretation. C1 NOAA, Natl Weather Serv Off, State Coll, PA 16801 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. RP Nicosia, DJ (reprint author), NOAA, Natl Weather Serv Off, 227 W Beaver Ave,Suite 402, State Coll, PA 16801 USA. RI Bryan, George/O-3849-2014 OI Bryan, George/0000-0002-2444-3039 NR 25 TC 9 Z9 10 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 1999 VL 14 IS 2 BP 271 EP 288 DI 10.1175/1520-0434(1999)014<0271:AFFFAL>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187XH UT WOS:000079813400008 ER PT J AU MacKeen, PL Brooks, HE Elmorer, KL AF MacKeen, PL Brooks, HE Elmorer, KL TI Radar reflectivity-derived thunderstorm parameters applied to storm longevity forecasting SO WEATHER AND FORECASTING LA English DT Article ID WSR-88D AB In order for the Federal Aviation Administration (FAA) to use airspace more efficiently during thunderstorm events, accurate storm longevity forecasts are needed. Relationships between 16 radar reflectivity-derived storm characteristics and storm longevity are examined to determine which, if any, of the storm characteristics are strongly related to storm lifetime. Such relationships are potentially useful for the development of storm longevity forecasts. The study includes 879 storms that formed over the Memphis, Tennessee, area during 15 late spring and summer convective days. Statistical analyses comparing all 16 storm characteristics to the observed remaining lifetime show that these storm characteristics are not good predictors for storm remaining lifetime. C1 NOAA, Environm Res Labs, Natl Severe Storms Lab, Norman, OK 73069 USA. RP MacKeen, PL (reprint author), NOAA, Environm Res Labs, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 20 TC 16 Z9 17 U1 0 U2 0 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 1999 VL 14 IS 2 BP 289 EP 295 DI 10.1175/1520-0434(1999)014<0289:RRDTPA>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 187XH UT WOS:000079813400009 ER PT J AU Gharrett, AJ Smoker, WW Reisenbichler, RR Taylor, SG AF Gharrett, AJ Smoker, WW Reisenbichler, RR Taylor, SG TI Outbreeding depression in hybrids between odd- and even-broodyear pink salmon SO AQUACULTURE LA English DT Article; Proceedings Paper CT 6th International Symposium on Genetics in Aquaculture CY JUN 22-28, 1997 CL UNIV STIRLING, STIRLING, SCOTLAND HO UNIV STIRLING DE outbreeding depression; conservation biology; salmonid; pink salmon; fluctuating asymmetry; meristics; cryopreservation ID ONCORHYNCHUS-GORBUSCHA; TIGRIOPUS-CALIFORNICUS; GENETIC-ANALYSIS; POPULATIONS; COPEPOD; SIZE AB Fewer F-2 hybrids between even- and odd-broodline pink salmon (Oncorhynchus gorbuscha), which are lines that are genetically isolated by their strict two-year life cycle, survived than did F-2 controls, indicating outbreeding depression. Cryopreserved sperm of 40 broodyear 1990 males and of 40 broodyear 1991 males fertilized equal subsamples Of eggs from 40 broodyear 1992 females. Return rates of F-1 hybrids (1.73%) and controls (1.63%) in 1994 did not differ significantly (P = 0.30), F-2 hybrid and control crosses were made from 40 males and 40 females selected at random from each return group. Offspring were differentially marked and released. In 1996, returns differed significantly (P = 0.011) between hybrids (n = 34, 0.34%) and controls (n = 44, 0.42%). The low rate of return of the control fish was similar to the measured return of a much larger group of tagged Auke Creek pink salmon, and probably not an artifact of the experiment. Although no increase in fluctuating asymmetry of paired meristic counts was observed in either F-1 or F-2 hybrids, size and some meristic counts of hybrids exceed measurements of controls, suggesting heterosis for those traits. The observations of decreased survival in F-2 hybrids confirm previous work [Gharrett, A.J., Smoker, W.W., 1991. Two generations of hybrids between even- and odd-year pink salmon (O. gorbuscha). Canadian Journal of Fisheries and Aquatic Science 48(9) 1744-1749]. Although genetic divergence between pink salmon broodlines is large and outbreeding depression might be expected in such unlikely hybrids, the results document;the occurrence of outbreeding depression in salmon and signal caution in making management and aquacultural decisions that may create the possibility of outbreeding depression in self-sustaining or cultured populations. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Alaska Fairbanks, Sch Fisheries & Ocean Sci, Div Fisheries, Juneau, AK 99801 USA. US Geol Survey, Biol Resources Div, Western Fisheries Res Ctr, Seattle, WA 98036 USA. Auke Bay Lab, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. RP Gharrett, AJ (reprint author), Univ Alaska Fairbanks, Sch Fisheries & Ocean Sci, Div Fisheries, 11120 Glacier Highway, Juneau, AK 99801 USA. EM ffajg@uaf.edu NR 40 TC 98 Z9 101 U1 1 U2 21 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD MAR 30 PY 1999 VL 173 IS 1-4 BP 117 EP 129 DI 10.1016/S0044-8486(98)00480-3 PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 181GG UT WOS:000079432600013 ER PT J AU Shannon, WD Banks, D AF Shannon, WD Banks, D TI Combining classification trees using MLE SO STATISTICS IN MEDICINE LA English DT Article AB We propose a probability distribution for an equivalence class of classification trees (that is, those that ignore the value of the cutpoints but retain tree structure). This distribution is parameterized by a central tree structure representing the true model, and a precision or concentration coefficient representing the variability around the central tree. We use this distribution to model an observed set of classification trees exhibiting variability in tree structure, We propose the maximum likelihood estimate of the central tree as the best tree to represent the set. This MLE retains the interpretability of a single tree model and has excellent generalizability, We implement an ascent search for the MLE tree structure using a data set of 13 classification trees that predict the presence or absence of cancer based on immune system parameters. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Washington Univ, Sch Med, Div Gen Med Sci, St Louis, MO 63110 USA. NIST, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Shannon, WD (reprint author), Washington Univ, Sch Med, Div Gen Med Sci, 660 S Euclid Ave,Box 8005, St Louis, MO 63110 USA. EM shannon@osler.wustl.edu NR 20 TC 25 Z9 25 U1 2 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0277-6715 J9 STAT MED JI Stat. Med. PD MAR 30 PY 1999 VL 18 IS 6 BP 727 EP 740 DI 10.1002/(SICI)1097-0258(19990330)18:6<727::AID-SIM61>3.0.CO;2-2 PG 14 WC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Medicine, Research & Experimental; Statistics & Probability SC Mathematical & Computational Biology; Public, Environmental & Occupational Health; Medical Informatics; Research & Experimental Medicine; Mathematics GA 177FB UT WOS:000079198900007 PM 10204200 ER PT J AU Borchers, JA Dura, JA Unguris, J Tulchinsky, D Kelley, MH Majkrzak, CF Hsu, SY Loloee, R Pratt, WP Bass, J AF Borchers, JA Dura, JA Unguris, J Tulchinsky, D Kelley, MH Majkrzak, CF Hsu, SY Loloee, R Pratt, WP Bass, J TI Observation of antiparallel magnetic order in weakly coupled Co/Cu multilayers SO PHYSICAL REVIEW LETTERS LA English DT Article ID GIANT MAGNETORESISTANCE; NEUTRON-SCATTERING; X-RAY; REFLECTION; INTERFACES; NANOWIRES; SURFACES AB Polarized neutron reflectivity and scanning electron microscopy with polarization analysis are combined to determine the magnetic structure of Co(6 nm)/Cu(6 nm) multilayers. These data resolve a controversy regarding the low-field state of giant-magnetoresistive (GMR) multilayers with weak coupling. As-prepared samples show a strong antiparallel correlation of in-plane ferromagnetic Co domains across the Cu. At the coercive field, the Co domains are uncorrelated. This irreversible transition explains the decrease in magnetoresistance from the as-prepared to the coercive state. For both states, the Co moments reside in domains with in-plane sizes of approximate to 0.5-1.5 mu m. [S0031-9007(99)08797-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Borchers, JA (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 21 TC 76 Z9 76 U1 2 U2 12 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 29 PY 1999 VL 82 IS 13 BP 2796 EP 2799 DI 10.1103/PhysRevLett.82.2796 PG 4 WC Physics, Multidisciplinary SC Physics GA 179UY UT WOS:000079348900044 ER PT J AU Mertens, CJ Mlynczak, MG Garcia, RR Portmann, RW AF Mertens, CJ Mlynczak, MG Garcia, RR Portmann, RW TI A detailed evaluation of the stratospheric heat budget - 1. Radiation transfer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HALOGEN OCCULTATION EXPERIMENT; MIDDLE ATMOSPHERE; COOLING RATES; CLIMATE MODELS; SULFURIC-ACID; AEROSOL; OZONE; REEXAMINATION; CIRCULATION; TEMPERATURE AB We present part 1 of a two-part series on a detailed evaluation of the stratospheric heat budget. In part 2 [Mlynczak et al., this issue] we present radiative heating, radiative cooling, net radiative heating, global radiation balance, radiative relaxation times, and diabatic circulations in the stratosphere using temperature and minor constituent data provided by instruments on the Upper Atmosphere Research Satellite (UARS) between 1991 and 1993 and by the limb infrared monitor of the stratosphere (LIMS) instrument, which operated on the Nimbus-7. spacecraft in 1978-1979. Here we describe the radiative transfer techniques used to compute the climatology of radiative heating and circulations given in part 2. Included in the radiation transfer calculations are heating due to absorption of solar radiation from the ultraviolet through near-infrared wavelengths and radiative cooling due to emission by carbon dioxide, water vapor, and ozone from 0 to 3000 cm(-1) (infinity-3.3 mu m). Infrared radiative effects of stratospheric aerosols are also considered in detail. C1 GATS Inc, Newport News, VA 23606 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Mertens, CJ (reprint author), GATS Inc, 11864 Canon Blvd,Suite 101, Newport News, VA 23606 USA. EM c.j.mertens@gats-inc.com; m.g.mlynczak@larc.nasa.gov; bportmann@al.noaa.gov RI Portmann, Robert/C-4903-2009; Mlynczak, Martin/K-3396-2012 OI Portmann, Robert/0000-0002-0279-6087; NR 49 TC 15 Z9 15 U1 0 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 1999 VL 104 IS D6 BP 6021 EP 6038 DI 10.1029/1998JD200100 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700004 ER PT J AU Mlynczak, MG Mertens, CJ Garcia, RR Portmann, RW AF Mlynczak, MG Mertens, CJ Garcia, RR Portmann, RW TI A detailed evaluation of the stratospheric heat budget - 2. Global radiation balance and diabetic circulations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MICROWAVE LIMB SOUNDER; ATMOSPHERE RESEARCH SATELLITE; HALOGEN OCCULTATION EXPERIMENT; MIDDLE ATMOSPHERE; INFRARED MONITOR; PLANETARY-WAVES; VALIDATION; OZONE; UARS; TRANSPORT AB We present a detailed evaluation of radiative heating, radiative cooling, net heating, global radiation balance, radiative relaxation times, and diabatic circulations in the stratosphere using temperature and minor constituent data provided by instruments on the Upper Atmosphere Research Satellite (UARS) between 1991 and 1993 and by the limb infrared monitor of the stratosphere (LIMS) instrument which operated on the Nimbus-7 spacecraft in 1978-1979. Included in the calculations are heating due to absorption of solar radiation from ultraviolet through near-infrared wavelengths and radiative cooling due to emission by carbon dioxide, water vapor, and ozone from 0 to 3000 cm(-1) (infinity-3.3 mu m). Infrared radiative effects of Pinatubo aerosols are also considered in some detail. In general, we find the stratosphere to be in a state of global mean radiative equilibrium on monthly timescales to within the uncertainty of the satellite-provided measurements. Radiative relaxation times are found to be larger in the lower stratosphere during UARS than LIMS because of the presence of Pinatubo aerosols. The meridional circulations in the upper stratosphere as diagnosed from the calculated fields of net heating are generally stronger in the UARS period than during the LIMS period, while the lower stratosphere meridional circulations are stronger during the LIMS period. A climatology of. these calculations is available to the community via a World Wide Web interface described herein. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. GATS Inc, Newport News, VA 23606 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Mlynczak, MG (reprint author), NASA, Langley Res Ctr, Mail Stop 401B, Hampton, VA 23681 USA. EM m.g.mlynczak@larc.nasa.gov; c.j.mertens@gats-inc.com; rgarcia@garcia.acd.ucar.edu; bportmann@al.noaa.gov RI Portmann, Robert/C-4903-2009; Mlynczak, Martin/K-3396-2012 OI Portmann, Robert/0000-0002-0279-6087; NR 50 TC 28 Z9 28 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 27 PY 1999 VL 104 IS D6 BP 6039 EP 6066 DI 10.1029/1998JD200099 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700005 ER PT J AU Atlas, D Ulbrich, CW Marks, FD Amitai, E Williams, CR AF Atlas, D Ulbrich, CW Marks, FD Amitai, E Williams, CR TI Systematic variation of drop size and radar-rainfall relations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RAINDROP SPECTRA; TOGA-COARE; CLASSIFICATION; PRECIPITATION; DISTRIBUTIONS; REFLECTIVITY; EVAPORATION; CLOUDS; SHAPE AB Time histories of the characteristics of the drop size distribution of surface disdrometer measurements collected at Kapingamarangi Atoll were partitioned for several storms using rain rate R, reflectivity factor Z, and median diameter of the distribution of water content D-0. This partitioning produced physically based systematic variations of the drop size distribution (DSD) and Z-R relations in accord with the precipitation types view-ed simultaneously by a collocated radar wind profiler. These variations encompass the complete range of scatter around the mean Z-R relations previously reported by Tokay, and Short [1996] for convective and stratiform rain and demonstrate that the scatter is not random. The systematic time or space variations are also consistent with the structure of mesoscale convective complexes with a sequence of convective, transition, and stratiform rain described by various authors. There is a distinct inverse relation between the coefficient A and the exponent of the Z-R relations which has been obscured in prior work because of the lack of proper discrimination of the rain types. Contrary to previous practice it is evident that there is also a distinct difference in the DSD and the Z-R relations between the initial convective and the trailing transition zones. The previously reported Z-R relation for convective rain is primarily representative of the transition rain that was included in the convective class. The failure of present algorithms to distinguish between the initial convective and the trailing transition rains causes an erroneous apportionment of the diabatic heating and cooling and defeats the primary intent of discriminating stratiform from convective rains. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. NOAA, Aeron Lab, Environm Res Labs, Boulder, CO 80303 USA. RP Atlas, D (reprint author), 16100 Golf Club Rd,Apt 302, Weston, FL 33326 USA. EM datlas@trmm.gsfc.nasa.gov RI Marks, Frank/A-5733-2011; Williams, Christopher/A-2723-2015 OI Marks, Frank/0000-0003-0371-5514; Williams, Christopher/0000-0001-9394-8850 NR 46 TC 113 Z9 115 U1 0 U2 6 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 1999 VL 104 IS D6 BP 6155 EP 6169 DI 10.1029/1998JD200098 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700012 ER PT J AU Pincus, R McFarlane, SA Klein, SA AF Pincus, R McFarlane, SA Klein, SA TI Albedo bias and the horizontal variability of clouds in subtropical marine boundary layers: Observations from ships and satellites SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AVERAGED SOLAR FLUXES; MICROPHYSICAL PROCESSES; PARAMETERIZATION; STRATOCUMULUS; ISCCP; LIQUID; MODELS AB Cloud optical properties vary dramatically at spatial scales smaller than typical grid cells in large-scale models, which can cause a significant overestimate of cloud albedo by the model. This plane parallel homogeneous (PPH) albedo bias exist may be reduced if the mean cloud optical thickness and the amount of variability are available, but little is known about how much variability exists in nature and to what factors it is sensitive. The authors combine 1331 observations made by volunteer surface observers with satellite imagery to assess the relationships between cloud fraction, cloud optical properties, and cloud type in marine boundary layer clouds off the coast of California during summer. Estimates of cloud fraction from the two datasets are in best agreement when a reflectance threshold between 0.09 and 0.10 is used. Satellite-derived cloud fraction increases slowly with sensor resolution at spatial scales from 1 to 32 km. Cloud fraction in scenes dominated by cumulus is much more sensitive to the reflectance threshold used for cloud detection than are scenes containing stratiform clouds. The mean magnitude of the PPH bias found here, 0.025, is considerably smaller than those found in other recent studies. When fit to the observed distributions of optical thickness both log-normal and gamma distributions substantially reduce the PPH bias. The mean and dispersion of log optical thickness are related to cloud type: optical thickness increases as cloud type changes from cumuliform to stratiform, while the relative amount of variability decreases. The authors suggest a basis for the parameterization of unresolved variability in large scale models. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Pincus, R (reprint author), Univ Wisconsin, Dept Atmospher & Ocean Sci, 1225 W Dayton St, Madison, WI 53706 USA. RI McFarlane, Sally/C-3944-2008; Pincus, Robert/B-1723-2013; Klein, Stephen/H-4337-2016 OI Pincus, Robert/0000-0002-0016-3470; Klein, Stephen/0000-0002-5476-858X NR 26 TC 50 Z9 52 U1 0 U2 6 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 1999 VL 104 IS D6 BP 6183 EP 6191 DI 10.1029/1998JD200125 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700014 ER PT J AU Csiszar, I Gutman, G AF Csiszar, I Gutman, G TI Mapping global land surface albedo from NOAA AVHRR SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HIGH-RESOLUTION RADIOMETER; CLEAR-SKY PLANETARY; NEAR-INFRARED CHANNELS; BIDIRECTIONAL REFLECTANCE; NARROW-BAND; SATELLITE-OBSERVATIONS; RADIATIVE FLUXES; DATA SET; MODELS; VEGETATION AB A set of algorithms is combined for a simple derivation of land surface albedo from measurements of reflected visible and near-infrared radiation made by the advanced very high resolution radiometer (AVHRR) onboard the National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites. The system consists of a narrowband- to-broadband conversion and bidirectional correction at the top of the atmosphere and an atmospheric correction. We demonstrate the results with 1 month worth of data from the NOAA National Environmental Satellite, Data, and Information Service (NESDIS) global vegetation index (GVI) weekly data set and the NOAA/NASA Pathfinder Atmosphere (PATMOS) project daily data. Error analysis of the methodology indicates that the surface albedo can be retrieved with 10-15% relative accuracy. Monthly albedo maps derived from September 1989 GVI and PATMOS data agree well except for small discrepancies attributed mainly to different preprocessing and residual atmospheric effects. A 5-year mean September map derived from the GVI multiannual time series is consistent with that derived from low-resolution Earth Radiation Budget Experiment data as well as with a September map compiled from ground observations and used in many numerical weather and climate models. Instantaneous GVI-derived albedos were found to be consistent with surface albedo measurements over various surface types. The discrepancies found can be attributed to differences in areal coverage and representativeness of the satellite and ground data. The present pilot study is a prototype for a routine real-time production of high-resolution global surface albedo maps from NOAA AVHRR Global Area Coverage (GAC) data. C1 NOAA, Off Res & Applicat, NESDIS, Camp Springs, MD 20746 USA. Univ Corp Atmospher Res, Boulder, CO USA. RP Csiszar, I (reprint author), NOAA, Off Res & Applicat, NESDIS, 5200 Auth Rd,Room 712, Camp Springs, MD 20746 USA. EM icsiszar@nesdis.noaa.gov RI Csiszar, Ivan/D-2396-2010 NR 63 TC 76 Z9 80 U1 2 U2 7 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 1999 VL 104 IS D6 BP 6215 EP 6228 DI 10.1029/1998JD200090 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700017 ER PT J AU Gutman, GG AF Gutman, GG TI On the use of long-term global data of land reflectances and vegetation indices derived from the advanced very high resolution radiometer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SEA-SURFACE TEMPERATURE; NDVI DATA SET; AVHRR DATA; INDEX; CALIBRATION; PRODUCTS; AFRICA; ISCCP; IDENTIFICATION; DROUGHT AB The availability of advanced very high resolution radiometer (AVHRR) time series of global shortwave data for the past two decades motivated many scientists to investigate interannual variability and trends in land surface conditions. For these studies the observed change in radiances due to two varying factors, namely, sensor responsivity and illumination conditions, must be known a priori because of the degradation of AVHRR shortwave channels and the orbit drift of afternoon spacecraft. The current work analyzes the behavior of global land AVHRR shortwave time series data for the last 12 years, processed using postlaunch calibration, and investigates their usefulness for the monitoring of global land surface processes. Its focus is on verifying the postlaunch calibrations for the AVHRR sensors on board NOAA 11 and 14. It is assumed that the NOAA 9 AVHRR calibration is correct so that the changing illumination effects can be parameterized based on its data. After accounting for the illumination effects, the residual trends in data, averaged over global deserts and rain forests, are attributed to calibration discrepancies. In particular. NOAA 11 calibration Tvas found to yield only small residuals, whereas NOAA 14 calibration produced significant unrealistic global increase in both reflectances and vegetation indices. The artificial trends caused by the combination of calibration residuals and satellite-orbit drift should be removed to alleviate their misidentification as real trends in Earth's climate system and to make statistical studies of anomalies more reliable. This study draws attention to the above aspects of time series analysis with the available global AVHRR data and suggests ways to improve these data for interannual variability studies. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Washington, DC 20233 USA. RP Gutman, GG (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, E-RA1, Washington, DC 20233 USA. EM ggutman@nesdes.noaa.gov NR 43 TC 143 Z9 143 U1 1 U2 11 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 1999 VL 104 IS D6 BP 6241 EP 6255 DI 10.1029/1998JD200106 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700019 ER PT J AU Pinto, JO Curry, JA Lynch, AH Persson, POG AF Pinto, JO Curry, JA Lynch, AH Persson, POG TI Modeling clouds and radiation for the November 1997 period of SHEBA using a column climate model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SEA-ICE; ARCTIC ATMOSPHERE; BOUNDARY-LAYER; PARAMETERIZATION; VARIABILITY; SIMULATION; LONGWAVE; SNOW AB A column version of the Arctic regional climate system model (ARCSYM) has been developed for testing general circulation model parameterizations in the Arctic. The ARCSYM column model has been employed for a 23-day period in November to simulate conditions over a multiyear ice flee that has been the site of intensive observations as part of the Surface Heat Budget of the Arctic (SHEBA) project. The large-scale tendencies of temperature, moisture, and wind are specified with values obtained from a special column data set obtained from the European Centre for Medium-Range Weather Forecasting. Comparisons between the ARCSYM column simulations and SHEBA data reveal that modeled temperature profiles are too cold aloft and generally too warm in the boundary layer. The occurrence of low clouds is severely underpredicted while the high cloud fraction is over predicted. The modeled longwave radiative cooling at the surface is 1.5-3 times as large as that observed. Much of this bias is related to problems with the treatment of clear-sky radiative transfer and in the simulated cloud optical properties. At the same time, the magnitude of modeled downward sensible heat flux at the surface is much too large. This has been related, in part, to the method for scaling temperature at the lowest modeled level to its surface air value under conditions of strong static stability. The importance of properly treating longwave radiative transfer under extremely cold, clear-sky conditions is evident in the sensitivity studies. The best simulation of cloud properties was achieved by assuming liquid cloud processes and properties at temperatures above 255 K. This temperature is significantly colder than that used in many climate models. The occurrence of supercooled clouds in the simulation dramatically reduced longwave cooling at the surface due to increases in the optical depth and fractional coverage of clouds. Results from a coupled sea ice-atmosphere simulation reveal that improvements in the atmospheric parameterizations are enhanced when the system is coupled. C1 Univ Colorado, Dept Aerosp Engn, Boulder, CO 80309 USA. NOAA, ETL, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Univ Colorado, Dept Aerosp Engn, Box 429, Boulder, CO 80309 USA. EM pinto@monsoon.colorado.edu RI Lynch, Amanda/B-4278-2011 OI Lynch, Amanda/0000-0003-2990-1016 NR 50 TC 33 Z9 33 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 27 PY 1999 VL 104 IS D6 BP 6661 EP 6678 DI 10.1029/98JD02517 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 180AY UT WOS:000079363700041 ER PT J AU Gnanadesikan, A AF Gnanadesikan, A TI A simple predictive model for the structure of the oceanic pycnocline SO SCIENCE LA English DT Article ID CIRCULATION MODELS; WIND-DRIVEN; TRANSPORTS; FLUXES; HEAT AB A simple theory for the large-scale oceanic circulation is developed, relating pycnocline depth, Northern Hemisphere sinking, and low-latitude upwelling to pycnocline diffusivity and Southern Ocean winds and eddies. The results show that Southern Ocean processes help maintain the global ocean structure and that pycnocline diffusion controls low-latitude upwelling. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RP Gnanadesikan, A (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB CN710, Princeton, NJ 08544 USA. EM gnana@splash.princeton.edu RI Gnanadesikan, Anand/A-2397-2008 OI Gnanadesikan, Anand/0000-0001-5784-1116 NR 28 TC 258 Z9 261 U1 0 U2 18 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD MAR 26 PY 1999 VL 283 IS 5410 BP 2077 EP 2079 DI 10.1126/science.283.5410.2077 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 180DH UT WOS:000079369800044 ER PT J AU Jensen, GC Johnson, RC AF Jensen, GC Johnson, RC TI Reinstatement and further description of Eualus subtilis Carvacho & Olson, and comparison with E-lineatus Wicksten & Butler (Crustacea : Decapoda : Hippolytidae) SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Eualus subtilis Carvacho & Olson 1984 is presently considered a synonym of E. lineatus Wicksten & Butler 1983. Comparisons of the two forms revealed differences in the armature of the antennular peduncle, stylocerite, and pereopods, as well as differences in color and maximum size, indicating that E. subtilis is a valid species. Furthermore, E. subtilis, unlike E. lineatus, exhibits marked sexual dimorphism, and characteristics of the previously undescribed, diminutive males of this species are provided. C1 Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. Natl Marine Fisheries Serv, SW Fisheries Ctr, Tiburon, CA 94920 USA. RP Jensen, GC (reprint author), Univ Washington, Sch Fisheries, Box 357980, Seattle, WA 98195 USA. NR 15 TC 2 Z9 2 U1 0 U2 0 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 MAR 23 PY 1999 VL 112 IS 1 BP 133 EP 140 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 182NQ UT WOS:000079505400012 ER PT J AU Bennett, SC Wieman, CE AF Bennett, SC Wieman, CE TI Measurement of the 6S -> 7S transition polarizability in atomic cesium and an improved test of the standard model SO PHYSICAL REVIEW LETTERS LA English DT Article ID HIGH-ACCURACY CALCULATION; WEAK NEUTRAL CURRENTS; PARITY NONCONSERVATION; HYPERFINE-STRUCTURE; PERTURBATION-THEORY; 6S-7S TRANSITION; HIGH ORDERS; PHYSICS; VIOLATION; SUMMATION AB The ratio of the off-diagonal hyperfine amplitude to the tensor transition polarizability (M-hf/beta for the 6S --> 7S transition in cesium has been measured. The value of beta = 27.024(43)(expt) (67)(theor)a(0)(3) is then obtained using an accurate semiempirical value of M-hf. This is combined with a previous measurement of parity nonconservation in atomic cesium and previous atomic structure calculations to determine the value of the weak charge. The uncertainties in the atomic structure calculations are updated land reduced) in light of new experimental tests. The result Q(w) = -72.06(28)(expt)(34)(theor) differs from the prediction of the standard model of elementary particle physics by 2.5 sigma. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Bennett, SC (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 28 TC 354 Z9 354 U1 1 U2 8 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 22 PY 1999 VL 82 IS 12 BP 2484 EP 2487 DI 10.1103/PhysRevLett.82.2484 PG 4 WC Physics, Multidisciplinary SC Physics GA 178HH UT WOS:000079259800016 ER PT J AU Armstrong, JT Van Assche, PHM AF Armstrong, JT Van Assche, PHM TI Can we believe the x-ray spectrum of masurium? SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20879 USA. Katholieke Univ Leuven, Dept Phys, B-3001 Heverlee, Belgium. NR 0 TC 0 Z9 0 U1 2 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 21 PY 1999 VL 217 MA 015-HIST BP U864 EP U864 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102699 ER PT J AU Bauer, BJ Prosa, TJ Liu, DW Jackson, CL Tomalia, DA Amis, EJ AF Bauer, BJ Prosa, TJ Liu, DW Jackson, CL Tomalia, DA Amis, EJ TI Molecularly dispersed dendrimers in a polymeric matrix. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. Michigan Mol Inst, Midland, MI 48640 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 21 PY 1999 VL 217 MA 031-POLY BP U525 EP U525 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148201614 ER PT J AU Coxon, B AF Coxon, B TI In search of boat conformations. A review of examples in the carbohydrate series. 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 21 PY 1999 VL 217 MA 011-CARB BP U221 EP U221 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148100589 ER PT J AU Coxon, B Sari, N Holden, MJ Mayhew, MP Vilker, VL AF Coxon, B Sari, N Holden, MJ Mayhew, MP Vilker, VL TI Studies of the structure and dynamics of putidaredoxin by nitrogen-15 NMR spectroscopy. 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 21 PY 1999 VL 217 MA 111-BIOT BP U186 EP U187 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148100493 ER PT J AU da Costa, CT Dalluge, JJ Margolis, SA Horton, D AF da Costa, CT Dalluge, JJ Margolis, SA Horton, D TI Liquid chromatography atmospheric-pressure chemical-ionization mass spectrometry (LC-APCI-MS) of C-glycosylxanthones from the root bark of the Osage orange (Maclura pomifera) tree SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 American Univ, Dept Chem, Washington, DC USA. 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 21 PY 1999 VL 217 MA 015-CARB BP U222 EP U223 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148100593 ER PT J AU Gaigalas, AK Li, L AF Gaigalas, AK Li, L TI Fluorescence from fluorophores immobilized on a modified gold electrode. 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 21 PY 1999 VL 217 MA 332-PHYS BP U376 EP U376 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148201135 ER PT J AU Heimer, TA Heilweil, EJ AF Heimer, TA Heilweil, EJ TI Electron recombination and halide oxidation dynamics at dye-sensitized TiO2 interfaces: Rate limitations for two related sensitizers. 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 21 PY 1999 VL 217 MA 360-PHYS BP U384 EP U385 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148201163 ER PT J AU Irikura, KK AF Irikura, KK TI Empirically corrected ab initio thermochemistry. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, 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 21 PY 1999 VL 217 MA 235-COMP BP U710 EP U710 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102210 ER PT J AU Irikura, KK Johnson, RD Gonzalez, CA Allison, TC Stevens, WJ AF Irikura, KK Johnson, RD Gonzalez, CA Allison, TC Stevens, WJ TI Infrastructure for quantum chemistry 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. 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 21 PY 1999 VL 217 MA 094-COMP BP U669 EP U669 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102069 ER PT J AU Jeon, HS Nakatani, AI Hsu, W Halasa, A Han, CC AF Jeon, HS Nakatani, AI Hsu, W Halasa, A Han, CC TI Phase inversion in viscoelastic polybutadiene (PB) polyisoprene (PI) blends SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. Goodyear Tire & Rubber Co, Akron, OH 44303 USA. RI Halasa, Adel/C-3716-2011 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 21 PY 1999 VL 217 MA 065-PMSE BP U410 EP U410 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148201232 ER PT J AU Kim, G Jackson, CL Von Gyldenfeldt, F Libera, M Stadler, R Han, CC AF Kim, G Jackson, CL Von Gyldenfeldt, F Libera, M Stadler, R Han, CC TI The crystallization behavior of polybutadiene-polycaprolactone (PB-PCL) semicrystalline block copolymer films. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. Univ Bayreuth, Bayreuth, Germany. Stevens Inst Technol, Hoboken, NJ 07030 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 21 PY 1999 VL 217 MA 066-PMSE BP U410 EP U410 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148201233 ER PT J AU Lee, K Wanninkhof, R Millero, FJ AF Lee, K Wanninkhof, R Millero, FJ TI Carbonic acid dissociation constants consistent with laboratory measurements and recently collected global CO2 data. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 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 21 PY 1999 VL 217 MA 084-GEOC BP U848 EP U849 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102653 ER PT J AU Massoth, GJ Feely, RA AF Massoth, GJ Feely, RA TI The important role of iron chemistry in hydrothermal plumes over Ridgecrest spreading centers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. NR 0 TC 0 Z9 0 U1 1 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 21 PY 1999 VL 217 MA 109-GEOC BP U855 EP U856 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102678 ER PT J AU Mayhew, MP Holden, MJ Reipa, V Vilker, VL AF Mayhew, MP Holden, MJ Reipa, V Vilker, VL TI Biocatalytic route for styrene conversion to styrene oxide. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 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 21 PY 1999 VL 217 MA 103-BIOT BP U184 EP U184 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148100485 ER PT J AU McDow, SR Binkowski, FS AF McDow, SR Binkowski, FS TI Comparison of predicted secondary aerosol yields from biogenic hydrocarbon precursors. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Penn, Sch Environm Sci Engn & Policy, Philadelphia, PA 19104 USA. NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 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 21 PY 1999 VL 217 MA 067-ENVR BP U734 EP U735 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102278 ER PT J AU Merzbacher, CI Rolison, DR Anderson, ML Cepak, VM Swider, KE AF Merzbacher, CI Rolison, DR Anderson, ML Cepak, VM Swider, KE TI Structural characterization of porous nanophase materials by contrast-matching SANS. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 USN, Res Lab, Washington, DC 20375 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 21 PY 1999 VL 217 MA 126-PHYS BP U313 EP U313 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148200929 ER PT J AU Ober, CK Xiang, ML Char, K Genzer, J Sivaniah, E Kramer, EJ Fisher, D AF Ober, CK Xiang, ML Char, K Genzer, J Sivaniah, E Kramer, EJ Fisher, D TI Low surface energy materials: Liquid-crystalline polymers with semifluorinated monodendron side groups. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Cornell Univ, Ithaca, NY 14853 USA. NIST, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, NSLS, Upton, NY 11973 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 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 21 PY 1999 VL 217 MA 159-PMSE BP U437 EP U437 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148201326 ER PT J AU Reid, JP Loomis, RA Leone, SR AF Reid, JP Loomis, RA Leone, SR TI Extended spectral cross-correlation applied to the state-resolved photofragmentation dynamics of deuterated ammonia species. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Dept Chem & Biochem, Boulder, CO 80309 USA. RI Reid, Jonathan/D-9411-2013 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 21 PY 1999 VL 217 MA 169-PHYS BP U326 EP U327 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148200972 ER PT J AU Terashima, N Hafren, J Westermark, U Atalla, RH VanderHart, DL AF Terashima, N Hafren, J Westermark, U Atalla, RH VanderHart, DL TI An improved C-13-tracer method as a promising analytical tool in lignin chemistry SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Forest Prod Lab, Madison, WI 53705 USA. STFI, S-11486 Stockholm, Sweden. Natl Inst Stand & Technol, 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 21 PY 1999 VL 217 MA 015-CELL BP U251 EP U251 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148100677 ER PT J AU Valoppi, L Petreas, M Donohoe, R Sullivan, L Callahan, C AF Valoppi, L Petreas, M Donohoe, R Sullivan, L Callahan, C TI Use of PCB congener analysis in ecological risk assessments. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 US Fish & Wildlife Serv, Sacramento, CA 95821 USA. US EPA, Cal, Washington, DC 20460 USA. NOAA, Washington, DC 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 21 PY 1999 VL 217 MA 183-ENVR BP U768 EP U768 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102390 ER PT J AU Vetter, TW Moreno-Ramirez, MG AF Vetter, TW Moreno-Ramirez, MG TI High-accuracy combined gravimetric and instrumental determination of silicon in zeolites. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Ctr Nacl Metrol, Queretaro, Mexico. 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 21 PY 1999 VL 217 MA 017-ANYL BP U102 EP U102 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148100239 ER PT J AU Weetall, HH AF Weetall, HH TI Chemical sensors and biosensors: Some problems and solutions. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Adv Technol Program, 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 21 PY 1999 VL 217 MA 230-ENVR BP U782 EP U782 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102439 ER PT J AU Xu, LH Lees, RM Hougen, JT AF Xu, LH Lees, RM Hougen, JT TI On the physical interpretation of torsion-rotation parameters in CH3OH and CH3CHO: Comparsion of global fit and ab initio results. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ New Brunswick, Dept Phys Sci, St John, NB E2L 4L5, Canada. Univ New Brunswick, Dept Phys, Fredericton, NB E3B 5A3, Canada. NIST, Opt Technol Div, 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 21 PY 1999 VL 217 MA 195-PHYS BP U334 EP U335 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 176JP UT WOS:000079148200998 ER PT J AU Zachariah, MR Burgess, D Tsang, W Westmoreland, PR AF Zachariah, MR Burgess, D Tsang, W Westmoreland, PR TI Reaction engineering of flame suppression: Integrating ab-initio computations to flow/chemistry modeling. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 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 21 PY 1999 VL 217 MA 062-COMP BP U659 EP U659 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102037 ER PT J AU Zhang, JZ AF Zhang, JZ TI The use of pH and buffer capacity to quantify the carbon cycle in the ocean. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NOAA, Atlantic Oceanog & Meteorol Lab, CIMAS, Miami, FL 33149 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 21 PY 1999 VL 217 MA 085-GEOC BP U849 EP U849 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 176JN UT WOS:000079148102654 ER PT J AU Slusser, J Gibson, J Bigelow, D Kolinski, D Mou, W Koenig, G Beaubien, A AF Slusser, J Gibson, J Bigelow, D Kolinski, D Mou, W Koenig, G Beaubien, A TI Comparison of column ozone retrievals by use of an UV multifilter rotating shadow-band radiometer with those from Brewer and Dobson spectrophotometers SO APPLIED OPTICS LA English DT Article ID PORTABLE SPECTRORADIOMETER INSTRUMENTS; IRRADIANCE; DERIVATION; ALGORITHM; MODEL AB The U.S. Department of Agriculture UV-B Monitoring Program measures ultraviolet light at seven wavelengths from 300 to 368 nm with an ultraviolet multifilter rotating shadow-band radiometer (UV-MFRSR) at 25 sites across the United States, including Mauna Loa, Hawaii. Column ozone has been retrieved under all-sky conditions near Boulder, Colorado (40.177 degrees N, 105.276 degrees W), from global irradiances of the W-MFRSR 332- and 305-nm channels (2 nm FWHM) using lookup tables generated from a multiple-scattering radiative transfer code suitable for solar zenith angles (SZA's) up to 90 degrees. The most significant sources of error for UV-MFRSR column ozone retrievals at SZA's less than 75 degrees are the spectral characterizations of the filters and the absolute calibration uncertainty, which together yield an estimated uncertainty in ozone retrievals of +/-4.0%. Using model sensitivity studies, we determined that the retrieved column ozone is relatively insensitive (<+/-2%) to typical variations in aerosol optical depth, cloud cover, surface pressure, stratospheric temperature, and surface albedo. For 5 months in 1996-1997 the mean ratio of column ozone retrieved by the W-MFRSR divided by that retrieved by the collocated Brewer was 1.024 and for the W-MFRSR divided by those from a nearby Dobson was 1.025. The accuracy of the retrieval becomes unreliable at large SZA's of more than 75 degrees as the detection limit of the 305-nm channel is reached and because of overall angular response errors. The W-MFRSR advantages of relatively low cost, unattended operation, automated calibration stability checks using Langley plots, and minimal maintenance make it a unique instrument for column ozone measurement. (C) 1999 Optical Society of America. C1 Colorado State Univ, Nat Resource Ecol Lab, UVB Radiat Monitoring Program, Ft Collins, CO 80523 USA. Univ Georgia, Dept Phys & Astron, Athens, GA 30602 USA. NOAA, Climate Monitoring Diagnost Lab, Boulder, CO 80303 USA. Yankee Environm Syst, Turners Falls, MA 01376 USA. RP Slusser, J (reprint author), Colorado State Univ, Nat Resource Ecol Lab, UVB Radiat Monitoring Program, Ft Collins, CO 80523 USA. EM sluss@nrel.colostate.edu NR 40 TC 31 Z9 32 U1 0 U2 2 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 1999 VL 38 IS 9 BP 1543 EP 1551 DI 10.1364/AO.38.001543 PG 9 WC Optics SC Optics GA 175VT UT WOS:000079116900020 PM 18305778 ER PT J AU Drobinski, P Dabas, AM Delville, P Flamant, PH Pelon, J Hardesty, RM AF Drobinski, P Dabas, AM Delville, P Flamant, PH Pelon, J Hardesty, RM TI Refractive-index structure parameter in the planetary boundary layer: comparison of measurements taken with a 10.6-mu m coherent lidar, a 0.9-mu m scintillometer, and in situ sensors SO APPLIED OPTICS LA English DT Article ID DOPPLER LIDAR; RANDOM-MEDIA; ATMOSPHERIC-TURBULENCE; 4TH MOMENT; PERFORMANCE; PROPAGATION; TEMPERATURE; DISPERSION; EFFICIENCY; HUMIDITY AB An optical technique is described that determines the path-averaged value of a refractive-index structure parameter at 10.6 mu m by use of a pulsed coherent CO2 Lidar in direct detection and hard-target returns. The Lidar measurements are compared with measurements taken by a 0.9-mu m scintillometer and temperature probe (with humidity corrections). The experimental results show good agreement far C-n(2) greater than or equal to 10(-14) m(-2/3). With respect to practical applications the new technique permits C-n(2) lidar measurements in a neutral meteorological situation to an unstably stratified convective boundary layer over long ranges (1 km or more). (C) 1999 Optical Society of America. C1 Ecole Polytech, Meteorol Dynam Lab, F-91128 Palaiseau, France. Meteo France, Ctr Natl Rech Meteorol, Toulouse, France. Univ Paris 06, Serv Aeron, Paris, France. NOAA, Wave Propagat Lab, Environm Res Lab, Boulder, CO 80303 USA. RP Drobinski, P (reprint author), Ecole Polytech, Meteorol Dynam Lab, F-91128 Palaiseau, France. EM drobi@colisa.polytechnique.fr RI Hardesty, Robert/H-9844-2013 NR 30 TC 12 Z9 12 U1 0 U2 1 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 1999 VL 38 IS 9 BP 1648 EP 1656 DI 10.1364/AO.38.001648 PG 9 WC Optics SC Optics GA 175VT UT WOS:000079116900026 PM 18305785 ER PT J AU Ciddor, PE Hill, RJ AF Ciddor, PE Hill, RJ TI Refractive index of air. 2. Group index SO APPLIED OPTICS LA English DT Article ID PULSE-PROPAGATION AB In a previous paper [Appl. Opt. 35, 1566 (1996)] one of us presented new equations for evaluation of the phase refractive index of air over a range of wavelengths and atmospheric parameters. That paper also gave an incorrect, although sufficiently accurate, procedure for calculating the group refractive index. Here we describe the results of a more rigorous derivation of the group index that takes proper account of the Lorentz-Lorenz formula, and we demonstrate that deviations fi om the Lorentz-Lorenz formula are insignificant to within a foreseeable precision of dispersion measurements for atmospheric conditions. We also derive and evaluate a simplification of the resultant equation that is useful for exploratory calculations. We clarify the limits of validity of the standard equation for the group refractive index and correct some minor errors in the previous paper. C1 CSIRO, Natl Measurement Lab, Sydney, NSW 2070, Australia. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Ciddor, PE (reprint author), CSIRO, Natl Measurement Lab, POB 218, Sydney, NSW 2070, Australia. EM philip.ciddor@tip.csiro.au NR 15 TC 47 Z9 51 U1 2 U2 15 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 1999 VL 38 IS 9 BP 1663 EP 1667 DI 10.1364/AO.38.001663 PG 5 WC Optics SC Optics GA 175VT UT WOS:000079116900028 PM 18305787 ER PT J AU Ryerson, TB Huey, LG Knapp, K Neuman, JA Parrish, DD Sueper, DT Fehsenfeld, FC AF Ryerson, TB Huey, LG Knapp, K Neuman, JA Parrish, DD Sueper, DT Fehsenfeld, FC TI Design and initial characterization of an inlet for gas-phase NOy measurements from aircraft SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CATALYTIC REDUCTION TECHNIQUE; NITRIC-OXIDE; HIGH-SENSITIVITY; NITROGEN; AIR; OZONE; ACID AB An understanding of gas-phase HNO3 transmission through an inlet is necessary to evaluate the quality of NOy measurements from an aircraft platform. A simple, inexpensive, low-volume Tenon inlet Is described and its suitability as an aircraft inlet for gas-phase NOy is assessed. Aerosol transmission is not characterized, but inlet design and orientation probably discriminates against the majority of aerosol by mass. Laboratory data, in-flight HNO3 standard addition calibrations, and ambient NOy measurements from the 1997 North Atlantic Regional Experiment aircraft mission are used to characterize inlet transmission efficiencies and time constants. Laboratory tests show high transmission efficiencies for HNO3 which are relatively independent of ambient temperature and humidity. In-flight standard addition calibrations were carried out at ambient temperatures ranging from -20 degrees to +8 degrees C and relative humidities from 3% to 71%. These data suggest that nearly all the sampled air contacts an inlet surface, with 90% of added HNO3 being transmitted in similar to 1.5 s. Ambient data are presented to demonstrate negligible hysteresis in l-Hz NOy measurements, relative to variability observed in ozone data, from an air mass where HNO3 is expected to be a large fraction of the total NOy. Power spectra of ambient NOy (at temperatures from -35 degrees to +35 degrees C and relative humidities from 3% to 100%) and ozone measurements suggest an effective NOy instrument time constant of similar to 2 s. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Ryerson, TB (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM tryerson@al.noaa.gov RI Neuman, Andy/A-1393-2009; Parrish, David/E-8957-2010; Ryerson, Tom/C-9611-2009; Fehsenfeld, Frederick/I-4876-2013 OI Neuman, Andy/0000-0002-3986-1727; Parrish, David/0000-0001-6312-2724; NR 21 TC 77 Z9 77 U1 0 U2 17 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 20 PY 1999 VL 104 IS D5 BP 5483 EP 5492 DI 10.1029/1998JD100087 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 177WV UT WOS:000079234800003 ER PT J AU Vay, SA Anderson, BE Conway, TJ Sachse, GW Collins, JE Blake, DR Westberg, DJ AF Vay, SA Anderson, BE Conway, TJ Sachse, GW Collins, JE Blake, DR Westberg, DJ TI Airborne observations of the tropospheric CO2 distribution and its controlling factors over the South Pacific Basin SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; EDDY DIFFUSION-MODEL; TRANSPORT; OCEAN; ATLANTIC; REGION; CYCLE AB Highly precise measurements of CO2 mixing ratios were recorded aboard both the NASA DC-8 and P3-B aircraft during the Pacific Exploratory Mission-Tropics conducted in August-October 1996. Data were obtained at altitudes ranging from 0.1 to 12 km over a large portion of the South Pacific Basin representing the most geographically extensive CO2 data set recorded in this region. These data along with CO2 surface measurements from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory (NOAA/CMDL) and the National Institute of Water and Atmospheric Research (NIWA) were examined to establish vertical and meridional gradients. The CO2 spatial distribution in the southern hemisphere appeared to be largely determined by interhemispheric transport as air masses with depleted CO2 levels characteristic of northern hemispheric air were frequently observed south of the Intertropical Convergence Zone. However, regional processes also played a role in modulating background concentrations. Comparisons of CO2 with other trace gases indicated that CO2 values were influenced by continental sources. Large scale plumes from biomass burning activities produced enhanced CO2 mixing ratios within the lower to midtroposphere over portions of the remote Pacific. An apparent CO2 source was observed in the NOAA/ CMDL surface data between 15 degrees N and 15 degrees S and in the lower altitude flight data between 8 degrees N and 8.5 degrees S with a zone of intensity from 6.5 degrees N to 1 degrees S. Inferred from these data is the presence of a Southern Ocean sink from south of 15 degrees S having two distinct zones seasonally out of phase with one another. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Sci & Technol Corp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Aerosp Elect Syst Div, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA 23666 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Vay, SA (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. EM s.a.vay@larc.nasa.gov NR 37 TC 35 Z9 36 U1 0 U2 2 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 20 PY 1999 VL 104 IS D5 BP 5663 EP 5676 DI 10.1029/98JD01420 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 177WV UT WOS:000079234800015 ER PT J AU Gonzalez, C Lim, EC AF Gonzalez, C Lim, EC TI Ab initio and MM3 studies of the conformational structures of naphthalene trimer: Comparison with experiment SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SMALL BENZENE CLUSTERS; EXCIMER FORMATION; MOLECULAR MECHANICS; ENERGY MINIMIZATION; RAMAN-SPECTROSCOPY; AROMATIC CLUSTERS; DIMER; DYNAMICS; PHOTODISSOCIATION; ALGORITHMS AB An ab initio study of the ground-state conformational geometries of the naphthalene trimer, (C10H8)(3), has been made at the MP2/6-31G and MP2/6-31+G//MP2/6-31G levels of theory. The lowest-energy structure was found to be the edge-to-face cyclic (C-3h) geometry in which the three equivalent naphthalene moieties are arranged with their long in-plane axes parallel. The fully optimized MP2/6-31G structure has a center-to-center intermoiety distance of 4.986 Angstrom and an angle of 48.0 degrees between the short in-plane axis of a naphthalene moiety and the Line connecting the center-of-mass of the monomer with that of the trimer. The computed rotational constants (B = 0.00555 and C = 0.00468 cm(-1)) for the oblate symmetric top are essentially identical to the experimental values (B = 0.00557 and C = 0.00470 cm(-1)) obtained from rotational coherence spectroscopy (see the following Letter by Benharash, Gleason, and Felker). Molecular mechanics (MM3) calculations also yield the same C3h trimer as the minimum-energy structure. The result suggests that, with the optimization and reparametrizations of the existing force fields to fit the ab initio (or experimental, where available) geometry/energy for selected dimers and small clusters, it may be possible to develop accurate and practical intermolecular potentials for aromatic clusters. C1 Univ Akron, Dept 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, Akron, OH 44325 USA. EM elim@uakron.edu NR 37 TC 31 Z9 31 U1 1 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 MAR 18 PY 1999 VL 103 IS 11 BP 1437 EP 1441 DI 10.1021/jp984374e PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 181TL UT WOS:000079458500001 ER PT J AU Deng, L Hagley, EW Wen, J Trippenbach, M Band, Y Julienne, PS Simsarian, JE Helmerson, K Rolston, SL Phillips, WD AF Deng, L Hagley, EW Wen, J Trippenbach, M Band, Y Julienne, PS Simsarian, JE Helmerson, K Rolston, SL Phillips, WD TI Four-wave mixing with matter waves SO NATURE LA English DT Article ID ATOMS AB The advent of the laser as an intense source of coherent light gave rise to nonlinear optics, which now plays an important role in many areas of science and technology. One of the first applications of nonlinear optics was the multi-wave mixing(1,2) of several optical fields in a nonlinear medium (one in which the refractive index depends on the intensity of the held) to produce coherent light ofa new frequency The recent experimental realization of the matter-wave laser'(3,4)-based on the extraction of coherent atoms from a Bose-Einstein condensat(5)-opens the way for analogous experiments with intense sources of matter waves: nonlinear atom optics(6). Here we report coherent four-wave mixing in which three sodium matter waves of differing momenta mix to produce, by means of nonlinear atom-atom interactions, a fourth wave with new momentum. We find a clear signature of a four-wave mixing process in the dependence of the generated matter wave on the densities of the input waves. Our results may ultimately facilitate the production and investigation of quantum correlations between matter waves. C1 Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. Georgia So Univ, Dept Phys, Statesboro, GA 30460 USA. Ben Gurion Univ Negev, Dept Chem & Phys, IL-84105 Beer Sheva, Israel. RP Deng, L (reprint author), Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RI Deng, Lu/B-3997-2012; Hagley, Edward/B-4285-2012; Helmerson, Kristian/E-3683-2013; rolston, steven/L-5175-2013; Julienne, Paul/E-9378-2012 OI rolston, steven/0000-0003-1671-4190; Julienne, Paul/0000-0002-5494-1442 NR 12 TC 394 Z9 407 U1 3 U2 46 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAR 18 PY 1999 VL 398 IS 6724 BP 218 EP 220 DI 10.1038/18395 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 177UA UT WOS:000079228400046 ER PT J AU Storebakken, T Kvien, IS Shearer, KD Grisdale-Helland, B Helland, SJ AF Storebakken, T Kvien, IS Shearer, KD Grisdale-Helland, B Helland, SJ TI Estimation of gastrointestinal evacuation rate in Atlantic salmon (Salmo salar) using inert markers and collection of faeces by sieving: evacuation of diets with fish meal, soybean meal or bacterial meal SO AQUACULTURE LA English DT Article; Proceedings Paper CT VII International Symposium on Nutrition and Feeding of Fish CY AUG 11-15, 1996 CL TEXAS A&M UNIV, COLLEGE STN, TEXAS HO TEXAS A&M UNIV DE passage rate; gastrointestinal evacuation; inert marker; yttrium oxide; ytterbium oxide; fish meal; soybean meal; bacterial protein; Atlantic salmon (Salmo salar) ID RAINBOW-TROUT; GASTRIC EVACUATION; DISTAL INTESTINE; BODY-WEIGHT; FEED-INTAKE; TRACT; TEMPERATURE; DIGESTION; PASSAGE; SIZE AB Gastrointestinal evacuation of Atlantic salmon was estimated using yttrium and ytterbium oxides (Y2O3 and Yb2O3) and collection of faeces from the outlet water of the tanks by sieving. The fish were fed three diets with different protein sources: fish meal (FM) (55% FM), soybean meal (SBM) (35% FM and 31% SBM); and bacterial meal (BM) (34% FM and 20% BM). The fish size was 0.15-0.20 kg and the water temperature was 9 degrees C, Rate of passage was estimated by first feeding the fish the diets labelled with the inert marker Y2O3 and then changing to the same diets labelled with Yb2O3, Faeces were obtained by sieving of the outlet water and were pooled by tank every 3 h for 81 h after the switch in diets. The evacuation of the diets was expressed as the percent-wise ratio between Yb2O3 and the sum of inert markers (Y2O3 + Yb2O3) in the faeces. For all three diets, ytterbium (Yb2O3) was first quantifiable in the faeces 12-15 h after the change of marker, and the gastrointestinal evacuation was almost complete 30 h after the switch, when yttrium (Y2O3) still accounted for up to 2% of the marker. The estimated rates of passage were described by s-shaped curves (R-2 greater than or equal to 0.98). The estimated time for Yb2O3 to reach 50% of the maximum marker concentration was approximately 18 h after the marker change in the fish fed the diets with FM and BM, while the corresponding value was approximately 20 h for the SBM diet. This was attributed to a slower onset of evacuation for the diet with SBM. The combination of two inert dietary markers and continuous collection of faeces permitted accurate estimation of gastrointestinal evacuation in salmon during feeding, without disturbing or stressing the fish. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Agr Res Council Norway, Inst Aquaculture Res, AKVAFORSK, N-6600 Sunndalsora, Norway. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Storebakken, T (reprint author), Agr Res Council Norway, Inst Aquaculture Res, AKVAFORSK, N-6600 Sunndalsora, Norway. EM trond.storebakken@akvaforsk.nlh.no RI storebakken, trond/E-8050-2011 OI storebakken, trond/0000-0002-4525-2098 NR 30 TC 40 Z9 45 U1 4 U2 27 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 1999 VL 172 IS 3-4 BP 291 EP 299 DI 10.1016/S0044-8486(98)00501-8 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 170WZ UT WOS:000078831200006 ER PT J AU Rea, LD Rosen, DAS Trites, AW AF Rea, LD Rosen, DAS Trites, AW TI Seasonal differences in adaptation to prolonged fasting in juvenile steller sea lions(Eumetopias jubatus). SO FASEB JOURNAL LA English DT Meeting Abstract C1 NOAA, Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Seattle, WA 98115 USA. Univ British Columbia, Marine Mammal Res Unit, Fisheries Ctr, Vancouver, BC V6T 1Z4, Canada. NR 0 TC 2 Z9 2 U1 0 U2 1 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAR 15 PY 1999 VL 13 IS 5 SU S BP A740 EP A740 PN 2 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 228JG UT WOS:000082132900541 ER PT J AU Alpay, SP Nagarajan, V Bendersky, LA Vaudin, MD Aggarwal, S Ramesh, R Roytburd, AL AF Alpay, SP Nagarajan, V Bendersky, LA Vaudin, MD Aggarwal, S Ramesh, R Roytburd, AL TI Effect of the electrode layer on the polydomain structure of epitaxial PbZr0.2Ti0.8O3 thin films SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; MISFIT RELAXATION MECHANISMS; DOMAIN CONFIGURATIONS; FERROELECTRIC PROPERTIES; FERROELASTIC FILMS; GROWTH; MICROSTRUCTURE; HETEROSTRUCTURES; DEFECTS; STRAIN AB PbZr0.2Ti0.8O3(PZT) thin films with and without La0.5Sr0.5CoO3(LSCO) electrodes were grown epitaxially on (001) SrTiO3 at 650 degrees C by pulsed laser deposition. The domain structure of the 400 nm thick PZT films with different electrode layer configurations was investigated by x-ray diffraction and transmission electron microscopy. The c-domain fractions of the PZT films with no electrode layer, with a 50 nm electrode layer between the film and the substrate, and with 50 nm electrode layers on top and bottom of the PZT film were found to be equal. Theoretical estimation of the c-domain fraction based on the minimization of the energy of internal stresses in films is in good agreement with experimental results. This means that depolarizing fields do not affect the polydomain structure of the film. Calculations of the in-plane strains based on the lattice parameters of the LSCO layer in the above configurations led to the conclusion that the bottom electrode layer is coherently strained to match the substrate. (C) 1999 American Institute of Physics. C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Alpay, SP (reprint author), Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RI valanoor, nagarajan/B-4159-2012; Alpay, Pamir/E-2666-2013 NR 35 TC 74 Z9 77 U1 2 U2 20 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 15 PY 1999 VL 85 IS 6 BP 3271 EP 3277 DI 10.1063/1.369670 PG 7 WC Physics, Applied SC Physics GA 174EM UT WOS:000079021200039 ER PT J AU Lugez, CL Jacox, ME Johnson, RD AF Lugez, CL Jacox, ME Johnson, RD TI Vibrational spectra of molecular ions isolated in solid neon. XV. Infrared spectroscopic evidence for NeHF+ and HFFH+ SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RESOLUTION ELECTRONIC SPECTROSCOPY; LASER-ABSORPTION-SPECTROSCOPY; TRANSITION-STATE REGION; DIPOLE-BOUND ANION; PHOTOELECTRON-SPECTROSCOPY; MATRIX-ISOLATION; AB-INITIO; DISSOCIATION-ENERGIES; HYDROGEN-FLUORIDE; PROTON AFFINITIES AB When a Ne: HF mixture is subjected to Penning ionization and/or photoionization by neon atoms in their first excited states, between 16.6 and 16.85 eV, and the products are rapidly frozen at approximately 5 K, the infrared spectrum of the resulting deposit includes absorptions assigned to NeHF+ and HFFH+. Evidence is presented suggesting that neon-matrix shifts may be anomalously large for protonated molecules which are derived from species with proton affinities near or below 550 kJ/mol. The results of earlier ab initio studies, as well as those of the present experimental and ab initio studies, indicate that the NeHF+ complex is quite strongly bound. The nu(3) absorptions of NeHF+ and NeDF+ and the nu(1) + nu(3) absorption of NeHF+ are tentatively identified. An absorption at 3064.7 cm(-1) has isotopic substitution behavior appropriate for its assignment to HFFH+. Density functional calculations were performed in order to estimate the positions of the harmonic vibrational fundamentals of HFFH+-d(n), and a more elaborate two-dimensional calculation on the HF-stretching potential surface was conducted in an attempt to take into account the large anharmonic contribution. Processes which occur on ultraviolet irradiation of the deposit are considered. (C) 1999 American Institute of Physics. [S0021-9606(99)00711-4]. C1 NIST, Opt Technol Dr, Gaithersburg, MD 20899 USA. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NIST, US Dept Commerce, Technol Adm, Gaithersburg, MD 20899 USA. RP Lugez, CL (reprint author), NIST, Opt Technol Dr, Gaithersburg, MD 20899 USA. NR 82 TC 14 Z9 14 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 15 PY 1999 VL 110 IS 11 BP 5037 EP 5046 DI 10.1063/1.478402 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 174AP UT WOS:000079012200007 ER PT J AU Mackenzie, SR Votava, O Fair, JR Nesbitt, DJ AF Mackenzie, SR Votava, O Fair, JR Nesbitt, DJ TI On the efficient generation of Ar-n-SH free-radical clusters via ultraviolet photolysis of closed-shell Ar-n-H2S complexes SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RESOLUTION ELECTRONIC SPECTROSCOPY; ENHANCED VIBRATIONAL DEACTIVATION; LASER-INDUCED FLUORESCENCE; ROTATIONAL ENERGY-LEVELS; INFRARED-SPECTROSCOPY; OH-AR; PHOTODISSOCIATION DYNAMICS; INTERMOLECULAR FORCES; A2-SIGMA+ STATE; KR AB Detailed investigations are described for the generation of open-shell radical complexes formed by unimolecular photolysis of closed-shell van der Waals precursors. As a specific test case, ultraviolet photolysis of slit-jet cooled Ar-n-H2S (n less than or equal to 2) complexes at both 248 and 193 nm are shown to yield Ar-SH and Ar-2-SH radical cluster species with surprisingly high efficiencies. Analysis of the laser induced fluorescence (LIF) spectra indicates that the radical complexes are produced with extensive van der Waals stretch/bend and overall rotational excitation, which is consistent with a simple ballistic model of the dissociation dynamics. The LIF spectra obtained as a function of expansion distance downstream provide clear evidence for remarkably efficient cooling of the newly formed radical cluster species by low-energy collisions with jet-cooled inert gas atoms at approximate to 10 K. Spectrally resolved Ar-SH and Ar-2-SH LIF signals have been investigated as a function of Ar composition, which yields information on relative branching ratios for fragmentary (e. g., Ar-2-H2S-->Ar-SH+H+Ar) and nonfragmentary (e. g., Ar-2-H2S-->Ar-2-SH+H) photolysis events. (C) 1999 American Institute of Physics. [S0021-9606(99)00810-7]. C1 Univ Oxford, Phys & Theoret Chem Lab, Oxford OX1 3QZ, England. Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Mackenzie, SR (reprint author), Univ Oxford, Phys & Theoret Chem Lab, S Parks Rd, Oxford OX1 3QZ, England. OI Mackenzie, Stuart/0000-0002-3166-8631 NR 50 TC 18 Z9 18 U1 0 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 15 PY 1999 VL 110 IS 11 BP 5149 EP 5158 DI 10.1063/1.478410 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 174AP UT WOS:000079012200018 ER PT J AU Douglas, JF AF Douglas, JF TI Integral equation approach to condensed matter relaxation SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 2nd Workshop on Non-Equilibrium Phenomena in Supercooled Fluids, Gasses and Amorphous Materials CY SEP 27-OCT 02, 1998 CL PISA, ITALY ID MARKOV PROCESS EXPECTATIONS; ASYMPTOTIC EVALUATION; ULTRAMETRIC SPACES; LARGE TIME; POLYMER; SYSTEMS AB A model of relaxation in supercooled and entangled polymer liquids is developed starting from an integral equation describing relaxation in liquids near thermal equilibrium and probabilistic modelling of the dynamic heterogeneity presumed to occur in these complex fluids. The treatment of stress relaxation considers two types of dynamic heterogeneity-temporal heterogeneity reflecting the intermittency of particle motion in cooled liquids and spatial heterogeneity or particle clustering governed by Boltzmann's law. Exact solution of the model relaxation integral equation by fractional calculus methods leads to a two parameter family of relaxation functions for which the memory indices (beta, phi) provide measures of the influence of the temporal and spatial heterogeneity on the relaxation process. The exponent beta is related to the geometrical form of the spatial heterogeneity. Relaxation function classes are identified according to the asymptotics of the psi(t; beta, phi) functions at long and short times and their integrability properties. The integral equation model for relaxation provides a framework for understanding the existence of 'universality' in condensed matter relaxation under restricted circumstances. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. RP Douglas, JF (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 37 TC 10 Z9 10 U1 0 U2 1 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 15 PY 1999 VL 11 IS 10A BP A329 EP A340 DI 10.1088/0953-8984/11/10A/030 PG 12 WC Physics, Condensed Matter SC Physics GA 181PB UT WOS:000079449400030 ER PT J AU Glotzer, SC Donati, C AF Glotzer, SC Donati, C TI Quantifying spatially heterogeneous dynamics in computer simulations of glass-forming liquids SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 2nd Workshop on Non-Equilibrium Phenomena in Supercooled Fluids, Gasses and Amorphous Materials CY SEP 27-OCT 02, 1998 CL PISA, ITALY ID LENNARD-JONES MIXTURE; MODE-COUPLING THEORY; TRANSITION; RELAXATION AB We examine the phenomenon of dynamical heterogeneity in computer simulations of an equilibrium, glass-forming liquid. We describe several approaches for quantifying the spatial correlation of single-particle motion, and show that spatial correlations of particle displacements become increasingly long range as the temperature decreases toward the made-coupling critical temperature. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. RP Glotzer, SC (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. EM sharon.glotzer@nist.gov RI Donati, Claudio/J-5180-2012 NR 34 TC 50 Z9 51 U1 0 U2 8 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 15 PY 1999 VL 11 IS 10A BP A285 EP A295 DI 10.1088/0953-8984/11/10A/026 PG 11 WC Physics, Condensed Matter SC Physics GA 181PB UT WOS:000079449400026 ER PT J AU Van Heerden, D Gavens, AJ Foecke, T Weihs, TP AF Van Heerden, D Gavens, AJ Foecke, T Weihs, TP TI Evaluation of vapor deposited Nb/Nb5Si3 microlaminates SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT Engineering Foundation High Temperature Structural Silicides Conference CY MAY 25-29, 1998 CL HYANNIS, MASSACHUSETTS DE microlaminates; microstructural stability; tensile strength ID MECHANICAL-PROPERTIES; COMPOSITE; STRENGTH AB Alternating layers of Nb and amorphous Nb-Si were sputter deposited at room temperature and then annealed at elevated temperatures to produce microlaminates with flat, discrete layering and an equiaxed grain structure. The amorphous Nb-Si layers crystallize at temperatures between 740 and 800 degrees C depending upon whether the silicide was co-deposited from elemental targets, or directly deposited from a single composite target. The first phase to form on crystallization is Nb5Si3, but upon heating to 1000 degrees C for 3 h a second phase, metastable Nb3Si, forms. Annealing at 1200 degrees C for 3 h though, eliminates the Nb3Si phase. The microstructural stability of the microlaminates was examined by annealing samples at temperatures up to 1400 degrees C. In all cases very limited grooving was observed and there was no pinch-off of the layering. There was also no evidence of silicide precipitates in the Nb grains after high temperature anneals. The mechanical properties of the microlaminates were examined using room temperature tensile tests. The ultimate tensile strength of the microlaminates is 590-640 MPa. Examination of fracture surfaces from the samples reveals that the Nb layers blunt cracks in the silicide layers and contribute significantly to the observed room temperature strength of these microlaminates. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA. Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Van Heerden, D (reprint author), Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA. RI Weihs, Timothy/A-3313-2010 NR 14 TC 18 Z9 18 U1 0 U2 1 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 MAR 15 PY 1999 VL 261 IS 1-2 BP 212 EP 216 DI 10.1016/S0921-5093(98)01068-5 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 176KY UT WOS:000079151300027 ER PT J AU Reiss, ME Esber, CM Van Heerden, D Gavens, AJ Williams, ME Weihs, TP AF Reiss, ME Esber, CM Van Heerden, D Gavens, AJ Williams, ME Weihs, TP TI Self-propagating formation reactions in Nb/Si multilayers SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT Engineering Foundation High Temperature Structural Silicides Conference CY MAY 25-29, 1998 CL HYANNIS, MASSACHUSETTS DE silicides; foil; multilayers ID COMBUSTION; MODELS; FILMS AB Structural silicides with promising high temperature mechanical properties can be fabricated into near-net shapes using self-propagating high-temperature synthesis of powders. These silicides can also be formed from vapor deposited reactive multilayer foils. The foils typically contain hundreds of layers that alternate between two elements that will mix exothermically to form a compound. Once the formation reaction is ignited in a foil, it can self-propagate along the foil with a controlled velocity. This paper investigates self-propagating formation reactions in Nb;Si multilayers and demonstrates that their reaction velocities decrease as the individual Nb and Si layers thicken. The paper also explores the feasibility of forming the vapor-deposited foils, during reaction into complex shapes. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA. Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Reiss, ME (reprint author), Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA. RI Weihs, Timothy/A-3313-2010 NR 13 TC 88 Z9 92 U1 0 U2 15 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 MAR 15 PY 1999 VL 261 IS 1-2 BP 217 EP 222 DI 10.1016/S0921-5093(98)01069-7 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 176KY UT WOS:000079151300028 ER PT J AU Odashima, H Zink, LR Evenson, KM AF Odashima, H Zink, LR Evenson, KM TI Tunable far-infrared spectroscopy extended to 9.1 THz SO OPTICS LETTERS LA English DT Article ID FREQUENCY MEASUREMENTS; LASER; CONSTANTS; REGION AB We synthesized tunable far-infrared radiation at frequencies higher than 9 THz (300 cm(-1)) by mixing CO2 laser, (NH3)-N-15 laser, and microwave radiation in a W-Co metal-insulator-metal diode. We used this far-infrared radiation to accurately measure torsion-rotation transitions of CH3OH in the 8-9-THz region. We also measured the frequency of the aP(7, 3) (NH3)-N-15 laser transition. C1 Toyama Univ, Dept Phys, Toyama 9308555, Japan. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Odashima, H (reprint author), Toyama Univ, Dept Phys, Gofuku 3190, Toyama 9308555, Japan. NR 16 TC 11 Z9 11 U1 0 U2 3 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 MAR 15 PY 1999 VL 24 IS 6 BP 406 EP 407 DI 10.1364/OL.24.000406 PG 2 WC Optics SC Optics GA 175ZQ UT WOS:000079126300016 PM 18071521 ER PT J AU Carlisle, JA Shirley, EL Terminello, LJ Jia, JJ Callcott, TA Ederer, DL Perera, RCC Himpsel, FJ AF Carlisle, JA Shirley, EL Terminello, LJ Jia, JJ Callcott, TA Ederer, DL Perera, RCC Himpsel, FJ TI Band-structure and core-hole effects in resonant inelastic soft-x-ray scattering: Experiment and theory SO PHYSICAL REVIEW B LA English DT Article ID HEXAGONAL BORON-NITRIDE; ELECTRONIC-STRUCTURE; RAMAN-SCATTERING; FINE-STRUCTURE; FLUORESCENCE; GRAPHITE; EMISSION; ABSORPTION; SPECTROSCOPY; INSULATORS AB Inelastic x-ray scattering has been observed in the hexagonal forms of carbon (graphite) and boron nitride (hBN), both above and below their K edges. For excitation energies below the core threshold, inelastic-loss features are observed, which disperse linearly with excitation energy (Raman-like behavior). However, above the threshold, emission features that move in a nonlinear fashion are observed. We show that these two scattering regimes, which have previously been thought of as separate processes, viz,, resonant x-ray Raman scattering (below threshold) and resonant inelastic x-ray scattering (above threshold), are described by the same theory for resonant fluorescence. Simulated spectra, with and without excitonic effects, are presented and compared with experiment. We conclude, based on this comparison, that excitonic effects influence these spectra in two ways. Primarily, the total fluorescence yields are enhanced or reduced simply because of changes in the absorption cross sections. Second, excitonic effects on emission features can be pronounced near some excitonic resonances, and these changes are more significant for excitation further above the K edges, which we attribute to the multiplicity of core-excited states being probed. Based on these findings, we conclude that core-hole effects do not necessarily undermine an interpretation of the scattering in terms of a one-electron (noninteracting) picture, and that resonant fluorescence spectroscopy may be successfully used to probe the band structure of solids. [S0163-1829(99)08911-0]. C1 Virginia Commonwealth Univ, Richmond, VA 23284 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Tennessee, Knoxville, TN 37996 USA. Tulane Univ, New Orleans, LA 70118 USA. Lawrence Berkeley Lab, Ctr Xray Opt, Berkeley, CA 94720 USA. Univ Wisconsin, Madison, WI 53706 USA. RP Virginia Commonwealth Univ, Richmond, VA 23284 USA. EM jacarlis@vcu.edu NR 38 TC 50 Z9 51 U1 0 U2 16 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD MAR 15 PY 1999 VL 59 IS 11 BP 7433 EP 7445 DI 10.1103/PhysRevB.59.7433 PG 13 WC Physics, Condensed Matter SC Physics GA 182PQ UT WOS:000079507700038 ER PT J AU Ioffe, A Arif, M Jacobson, DL Mezei, F AF Ioffe, A Arif, M Jacobson, DL Mezei, F TI Precision neutron interferometric search for evidence of nuclear quantum entanglement in liquid H2O-D2O mixtures SO PHYSICAL REVIEW LETTERS LA English DT Article ID SCATTERING AB A wavelength independent neutron interferometry technique has been applied to measure the scattering length densities Nb of liquid mixtures of H2O-D2O near room temperature. The experimental data have been compared to the conventional theory based on two separate liquids, with no deviations greater than 0.4% observed. These results are not consistent with the predicted deviations due to quantum entanglement between protons and deuterons, which are at least an order of magnitude larger than our measured values. C1 Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Hahn Meitner Inst, Berlin Neutron Scattering Ctr, D-14109 Berlin, Germany. RP Ioffe, A (reprint author), Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. NR 9 TC 19 Z9 19 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 15 PY 1999 VL 82 IS 11 BP 2322 EP 2325 DI 10.1103/PhysRevLett.82.2322 PG 4 WC Physics, Multidisciplinary SC Physics GA 175QV UT WOS:000079107000025 ER PT J AU Arp, U Iemura, K Kutluk, G Nagata, T Yagi, S Yagishita, A AF Arp, U Iemura, K Kutluk, G Nagata, T Yagi, S Yagishita, A TI 3d photoionization of Xe, Cs and Ba and the collapse of the 4f wavefunction SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID 4D GIANT-RESONANCES; FLUORESCENCE YIELDS; EXCITATION-SPECTRA; HIGH-RESOLUTION; COSTER-KRONIG; RAY UNDULATOR; METAL ATOMS; SPECTROSCOPY; IONS; PHOTOABSORPTION AB Total photoion yield spectra in the vicinity of the 3d thresholds of Xe, Cs and Ba are presented. These spectra were recorded with higher photon energy resolution than previously reported. For xenon the new experimental data reveal additional structures. Employing Hartree-Fock calculations, the origin of the prominent resonances is explained: for Xe and Cs the main absorption features are caused by shape resonances above threshold, whereas for Ba it is revealed that the 4f orbital has finally collapsed and the sharp resonances are caused by discrete excitations into bound states. C1 Inst Mat Struct Sci KEK, Photon Factory, Tsukuba, Ibaraki 305, Japan. RP Arp, U (reprint author), Natl Inst Stand & Technol, Div Electron & Opt Phys, Gaithersburg, MD 20899 USA. RI Arp, Uwe/C-2854-2009; OI Arp, Uwe/0000-0002-6468-9455 NR 32 TC 24 Z9 24 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAR 14 PY 1999 VL 32 IS 5 BP 1295 EP 1304 DI 10.1088/0953-4075/32/5/019 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 181NX UT WOS:000079449000023 ER PT J AU Shi, Y Wang, SL Krueger, S Schwarz, FP AF Shi, Y Wang, SL Krueger, S Schwarz, FP TI Effect of mutations at the monomer-monomer interface of cAMP receptor protein on specific DNA binding SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID GENE ACTIVATOR PROTEIN; CYCLIC-AMP RECEPTOR; ESCHERICHIA-COLI; REGULATORY PROTEIN; THERMODYNAMICS; COMPLEX; SITE; CAP; TRANSCRIPTION; ASSOCIATION AB To determine the thermodynamic role of binding of an operon to cAMP receptor protein (CRP) in the activation of transcription, isothermal titration calorimetry measurements were performed on the binding of three 40-base pair DNA sequences to the cyclic nucleoside complexes of CRP and its mutants at 296 K, The three 40-base pair sequences consisted of a consensus DNA (conDNA) duplex derived from the CRP-binding site sequences of the operons activated by CRP and two DNA sequences based on the CRP-binding site sequences of the lac operon (lacDNA) and of the gal operon (galDNA), The mutants of CRP consisted of a T127L mutant, a S128A mutant, and a mutant containing both mutations (CRP*) which not only alter the transcriptional activity of the CRP complexes but also are involved in the monomer-monomer interfacial interactions of the CRP dimer, The binding reactions of the DNA duplexes to the fully cNMP-ligated CRP-mutant complexes were endothermic with binding constants as high as 6.6 +/- 1.1 x 10(6) M-1 (conDNA . CRP(cAMP)(2)). ConDNA binding to the unligated T127L and CRP* mutants was observed as well as conDNA and lacDNA binding to CRP with cAMP bound to only one monomer. The reduction of the binding constants with increase in KCl concentration indicated the formation of two ion pairs for the cAMP-ligated CRP and S128A complexes and four ion pairs for the cAMP-ligated T127L and CRP* complexes. Reduction of the DNA binding constants upon substitution of D2O for H2O in the buffer, the large heat capacity changes, and the enthalpy-entropy compensation exhibited by the binding reactions indicate the importance of dehydration in the binding reaction. Small angle neutron scattering measurements on the lacDNA . CRP(cAMP)(2) complex in D2O/ H2O mixtures show that the DNA is bent around the cAMP-ligated protein in solution. C1 Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Schwarz, FP (reprint author), Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. NR 34 TC 22 Z9 22 U1 1 U2 2 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD MAR 12 PY 1999 VL 274 IS 11 BP 6946 EP 6956 DI 10.1074/jbc.274.11.6946 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 175DV UT WOS:000079078400020 PM 10066748 ER PT J AU Hagley, EW Deng, L Kozuma, M Wen, J Helmerson, K Rolston, SL Phillips, WD AF Hagley, EW Deng, L Kozuma, M Wen, J Helmerson, K Rolston, SL Phillips, WD TI A well-collimated quasi-continuous atom laser SO SCIENCE LA English DT Article ID BOSE-EINSTEIN CONDENSATION AB Extraction of sodium atoms from a trapped Bose-Einstein condensate (BEC) by a coherent, stimulated Raman process is demonstrated. Optical Raman pulses drive transitions between trapped and untrapped magnetic sublevels, giving the output-coupled BEC fraction a well-defined momentum. The pulsed output coupling can be run at such a rate that the extracted atomic wave packets strongly overlap, forming a highly directional, quasi-continuous matter wave. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Georgia So Univ, Statesboro, GA 30460 USA. Univ Tokyo, Inst Phys, Tokyo 1538902, Japan. RP Hagley, EW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Deng, Lu/B-3997-2012; Hagley, Edward/B-4285-2012; Helmerson, Kristian/E-3683-2013; rolston, steven/L-5175-2013 OI rolston, steven/0000-0003-1671-4190 NR 17 TC 388 Z9 398 U1 0 U2 17 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 12 PY 1999 VL 283 IS 5408 BP 1706 EP 1709 DI 10.1126/science.283.5408.1706 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 175PF UT WOS:000079102800042 ER PT J AU Hoobler, RJ Leone, SR AF Hoobler, RJ Leone, SR TI Low-temperature rate coefficients for reactions of the ethynyl radical (C2H) with C3H4 isomers methylacetylene and allene SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER-INDUCED FLUORESCENCE; TITANS ATMOSPHERE; CN REACTIONS; 359 K; PHOTOCHEMISTRY; SPECTROSCOPY; KINETICS; NM AB Low-temperature rate coefficients for the reactions C2H + C3H4 --> products [C3H4 = methylacetylene (propyne) CH3CCH and allene (propadiene) CH2CCH2] are measured over the temperature range of 155-298 K. Absolute rate constants are determined using laser photolysis and transient infrared absorption spectroscopy. Both reactions are fast, approaching the kinetic limit and have either no temperature dependence or a slight negative temperature dependence. Over the experimental temperature range, the rate constants are fit to the following Arrhenius expressions: k(CH3CCH) = (1.6 +/- 0.4) X 10(-10) exp[(71 +/- 50)/T] cm(3) molecule(-1) s(-1) and k(CH2CCH2) = (1.3 +/- 0.6) x 10(-10) exp[(103 +/- 136)/T] cm(3) molecule(-1) s(-1). The corresponding rate constants at 298 K are k(CH3CCH) = (1.9 +/- 0.3) X 10(-10) cm(3) molecule(-1) s(-1) and k(CH2CCH2) = (1.7 +/- 0.3) X 10(-10) cm(3) molecule(-1) s(-1). These measurements provide new reaction rate coefficients for the ethynyl radical, C2H, with C3H4 unsaturated hydrocarbons. These are necessary to extend current photochemical models of Jupiter, Saturn, and its satellite Titan. C1 NIST, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ S Alabama, Dept Chem, Mobile, AL 36688 USA. RP Leone, SR (reprint author), NIST, JILA, Boulder, CO 80309 USA. NR 28 TC 35 Z9 35 U1 0 U2 5 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 11 PY 1999 VL 103 IS 10 BP 1342 EP 1346 DI 10.1021/jp9839596 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 177XL UT WOS:000079236300009 ER PT J AU Tewari, R Mukhopadhyay, P Banerjee, S Bendersky, LA AF Tewari, R Mukhopadhyay, P Banerjee, S Bendersky, LA TI Evolution of ordered omega phases in (Zr3Al)-Nb alloys SO ACTA MATERIALIA LA English DT Article ID QUENCHED BETA-BRASS; TRANSFORMATION; LATTICE; COGA AB Microstructural investigations on rapidly solidified Zr3Al based alloys (binary Zr3Al and ternary Zr3Al-3Nb and Zr3Al-10Nb) have revealed some unusual phase transformation sequences. The Zr5Al3 phase (D8(8) structure) has been found to occur in both the rapidly solidified ternary alloys unlike in the rapidly solidified stoichiometric Zr3Al alloy in which the Zr2Al phase (B8(2) structure) has been found to be present. The evolution of the D8(8) phase, which could be regarded as one of the ordered derivatives of the omega phase, could be described in terms of a superimposition of replacive and displacive ordering waves in the beta phase. The orientation relationship between the beta and the D8(8) phases has been established. The microstructural changes occurring in the rapidly solidified Zr3Al-Nb alloys during aging have been examined. It has been found that on aging the D8(8) phase gets transformed into the B8(2) phase which, on continued aging, transforms to other metastable and equilibrium phases, depending upon the aging temperature. The observed sequence of phase transformations involving different structurally related phases has been along the direction of progressively close packed structures. The symmetry changes associated with the sequence of omega related transformations have been summarized in the form of a symmetry tree. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Bhabha Atom Res Ctr, Div Mat Sci, Mumbai, India. NIST, Div Met, Gaithersburg, MD 20899 USA. RP Banerjee, S (reprint author), Bhabha Atom Res Ctr, Div Mat Sci, Mumbai, India. NR 48 TC 17 Z9 19 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD MAR 10 PY 1999 VL 47 IS 4 BP 1307 EP 1323 DI 10.1016/S1359-6454(98)00404-2 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 179PL UT WOS:000079337600022 ER PT J AU Frohlich, C Davis, SD AF Frohlich, C Davis, SD TI How well constrained are well-constrained T, B, and P axes in moment tensor catalogs? SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID EARTHQUAKE FOCAL MECHANISMS; DOUBLE-COUPLE COMPONENTS; SOURCE PARAMETERS; PLATE BOUNDARIES; WAVEFORM DATA; SEISMICITY; INVERSION; DEEP; INTERMEDIATE; GEOMETRY AB The T, B and P axes of earthquake moment tensors (MT) are often used to evaluate regional stress directions and other tectonic parameters; we here undertake three comparisons to assess the uncertainty in the orientations of these axes. These are (1) a direct comparison of common MT in the Harvard, U.S. Geological Survey, or Earthquake Research Institute (ERI) catalogs; (2) a comparison of MT slip vectors and plate motion vectors in several tectonically straightforward regions; and (3) an analysis of the axial variability in the Harvard and ERI catalogs implied by the reported uncertainties in individual MT components. All three comparisons indicate that there is considerable variability within the catalog concerning the axial orientation of MT, but all suggest that axis orientations of the majority of Harvard MT have uncertainties of 15 degrees or less. For compensated linear vector dipole (CLVD) components among the three catalogs, the correlation is very low. For the Harvard catalog, three statistics are especially useful for selecting better constrained MT; these are (1) the relative error E-rel, which is the ratio of the scalar moments of the reported error tensor and of the MT itself; (2) f(CLVD), a measure of the strength of the CLVD component; and (3) n(free), the number of MT elements not fixed at zero in the inversion. For selecting better constrained MT, the appropriate statistical cutoffs chosen depend on the problem of interest, the data available, and personal preference. However, for analysis of shallow earthquakes we have used E-rel less than or equal to 0.15, f(CLVD) less than or equal to 0.20, and n(free) = 6. While this eliminates 53% of the catalog, our calculations suggest that nearly all the remaining events have T, B, and P axes with azimuth and inclination angle uncertainties of 5 degrees-10 degrees or less. C1 Univ Texas, Inst Geophys, Austin, TX 78759 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Natl Geophys Data Ctr, Boulder, CO 80303 USA. RP Frohlich, C (reprint author), Univ Texas, Inst Geophys, 4412 Spicewood Springs Rd,Bldg 600, Austin, TX 78759 USA. EM cliff@utig.ig.utexas.edu; davis@clifty.com RI Frohlich, Cliff/A-8573-2008 NR 45 TC 70 Z9 71 U1 1 U2 4 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 MAR 10 PY 1999 VL 104 IS B3 BP 4901 EP 4910 DI 10.1029/1998JB900071 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 176HN UT WOS:000079145800010 ER PT J AU Marks, KM Stock, JM Quinn, KJ AF Marks, KM Stock, JM Quinn, KJ TI Evolution of the Australian-Antarctic discordance since Miocene time SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SEA-FLOOR; DEPTH ANOMALIES; PLUME MATERIAL; LATERAL FLOW; PLATES; OCEAN; BOUNDARY; RIDGE; SEGMENTATION; ROTATIONS AB In this study we chronicle the development of the Australian-Antarctic discordance (AAD), the crenelated portion of the Southeast Indian Ridge between similar to 120 degrees and 128 degrees E, since anomaly 6y time (19 Ma). We reconstruct satellite-derived marine gravity fields and depth anomalies at selected times by first removing anomalies overlying seafloor younger than the selected age, and then rotating the remaining anomalies through improved finite rotations based on a very detailed set of magnetic anomaly identifications. Our gravity field reconstructions reveal that the overall length of the Australian-Antarctic plate boundary within the AAD has been increasing since 19 Ma. Concomitantly, the number of propagating rifts and fracture zones in the vicinity of the discordance has increased dramatically in recent times, effectively dividing it into its present-day configuration of five distinct spreading corridors (B1-B5) that are offset alternately to the north and south and exhibit varying degrees of asymmetric spreading. Our bathymetric reconstructions show that the regional, arcuate-shaped, negative depth anomaly (deeper than predicted by normal lithospheric cooling models) presently centered on the discordance began migrating westward before anomaly 5ad time (similar to 14.4 Ma), and that a localized depth anomaly low, which at time 5ad lay on the ridge axis in spreading corridor B5, has been split apart by subsequent seafloor spreading. The magnetic anomaly patterns suggest that the depth anomaly is not always associated with a particularly contorted plate boundary geometry. Although the plate boundary within the AAD has been getting progressively more crenelated with time, this effect shows little to no migration along the ridge axis since 19 Ma. Thus any geodynamic models of the evolution of the discordance must account for the following observations: (1) the crenelation of the plate boundary within the AAD has increased with time, (2) the center of the crenelated zone does not appear to have migrated along the ridge crest, and (3) both the depth anomaly and the isotopic boundary between Pacific and Indian mantle have been migrating westward along the ridge axis but at apparently different rates. We suggest that both along-axis migration of the depth anomaly and isotopic boundary, as well as temporal variation in the upwelling mantle material beneath the AAD, and local tectonic effects are required in order to explain these observations. C1 NOAA, Natl Ocean Data Ctr, Lab Satell Altimetry, EOC2, Silver Spring, MD 20910 USA. CALTECH, Seismol Lab, Pasadena, CA 91125 USA. RP Marks, KM (reprint author), NOAA, Natl Ocean Data Ctr, Lab Satell Altimetry, EOC2, 1315 East West Highway,SSMC 3,Sta 3855, Silver Spring, MD 20910 USA. EM kmarks@nodc.noaa.gov; jstock@gps.caltech.edu; katyq@mit.edu RI Marks, Karen/F-5610-2010; OI Marks, Karen/0000-0001-6524-1495; Stock, Joann Miriam/0000-0003-4816-7865 NR 39 TC 17 Z9 17 U1 1 U2 4 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 MAR 10 PY 1999 VL 104 IS B3 BP 4967 EP 4981 DI 10.1029/1998JB900075 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 176HN UT WOS:000079145800014 ER PT J AU Heilweil, EJ AF Heilweil, EJ TI Molecular spectroscopy - Ultrafast glimpses at water and ice SO SCIENCE LA English DT Editorial Material ID RELAXATION; COMPLEXES C1 Natl Inst Stand & Technol, Phys Lab, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Heilweil, EJ (reprint author), Natl Inst Stand & Technol, Phys Lab, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 15 TC 16 Z9 16 U1 0 U2 5 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 5 PY 1999 VL 283 IS 5407 BP 1467 EP 1468 DI 10.1126/science.283.5407.1467 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 173AR UT WOS:000078959200029 ER PT J AU Wilkinson, C Linden, O Cesar, H Hodgson, G Rubens, J Strong, AE AF Wilkinson, C Linden, O Cesar, H Hodgson, G Rubens, J Strong, AE TI Ecological and socioeconomic impacts of 1998 coral mortality in the Indian Ocean: An ENSO impact and a warning of future change? SO AMBIO LA English DT Article AB The year 1998, was the warmest year since the start of temperature recordings some 150 years ago. Similarly, the 1990s have been the warmest decade recorded. In addition, 1998 saw the strongest El Nino ever recorded. As a consequence of this, very high water temperatures were observed in many parts of the oceans, particularly in the tropical Indian Ocean, often with temperatures of 3 degrees to 5 degrees C above normal. Many corals in this region bleached and subsequently died, probably due to the high water temperatures in combination with meteorological and climatic factors. Massive mortality occurred on the reefs of Sri Lanka, Maldives, India, Kenya, Tanzania, and Seychelles with mortalities of up to 90% in many shallow areas. Reefs in other parts of the Indian Ocean, or in waters below 20 m, coral mortality was typically 50%. Hence, coral death during 1998 was unprecedented in severity. The secondary socioeconomic effects of coral bleaching for coastal communities of the Indian Ocean are likely to be long lasting and severe. In addition to potential decreases in fish stocks and negative effects on tourism, erosion may become an acute problem, particularly in the Maldives and Seychelles. If the observed global trends in temperature rises continue, there will be an increased probability of a recurrence of the phenomenon observed in 1998 on the coral reefs of the Indian Ocean, as well as in other parts of the tropical oceans in coming years. Coral reefs of the Indian Ocean may prove to be an important signal of the potential effects of global climate change, and we should heed that warning. C1 Int Coral Reef Initiat, Global Coral Reef Monitoring Network, S Asia Reg Unit, Colombo, Sri Lanka. Univ Stockholm, Dept Zool, S-10691 Stockholm, Sweden. Free Univ Amsterdam, IvM, Inst Environm Studies, NL-1081 HV Amsterdam, Netherlands. Hong Kong Univ Sci & Technol, Inst Environm & Sustainable Dept, Clearwater Bay, Hong Kong. IUCN, Colombo 5, Sri Lanka. NOAA, Ctr Sci, Natl Environm Satellite Data & Informat Serv, Ocean Res & Applicat Div, Camp Springs, MD 20746 USA. USN Acad, Annapolis, MD 21402 USA. RP Wilkinson, C (reprint author), PMB 3, Townsville, Qld 4810, Australia. RI Strong, Alan/E-7924-2011 NR 28 TC 209 Z9 220 U1 10 U2 56 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0044-7447 J9 AMBIO JI Ambio PD MAR PY 1999 VL 28 IS 2 BP 188 EP 196 PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 194ER UT WOS:000080179600015 ER PT J AU Muller, R Grooss, JU McKenna, DS Crutzen, PJ Bruhl, C Russell, JM Gordley, LL Burrows, JP Tuck, AF AF Muller, R Grooss, JU McKenna, DS Crutzen, PJ Bruhl, C Russell, JM Gordley, LL Burrows, JP Tuck, AF TI Chemical ozone loss in the Arctic vortex in the winter 1995-96: HALOE measurements in conjunction with other observations (vol 16, pg 101, 1999) SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Correction C1 Forschungszentrum Julich, Inst Stratospher Chem, ICG 1, Julich, Germany. Max Planck Inst Chem, Atomospher Chem Dept, D-55128 Mainz, Germany. Hampton Univ, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Bremen, Inst Environm Phys, Bremen, Germany. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Muller, R (reprint author), Forschungszentrum Julich, Inst Stratospher Chem, ICG 1, Postfach 1913, Julich, Germany. RI Tuck, Adrian/F-6024-2011; Crutzen, Paul/F-6044-2012; Muller, Rolf/A-6669-2013; GrooSS, Jens-Uwe/A-7315-2013; McKenna, Daniel/E-7806-2014; Burrows, John/B-6199-2014 OI Tuck, Adrian/0000-0002-2074-0538; Muller, Rolf/0000-0002-5024-9977; GrooSS, Jens-Uwe/0000-0002-9485-866X; McKenna, Daniel/0000-0002-4360-4782; Burrows, John/0000-0002-6821-5580 NR 1 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD MAR PY 1999 VL 17 IS 3 BP 437 EP 437 PG 1 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 180KY UT WOS:000079386200012 ER PT J AU Bradley, CC Anderson, WR McClelland, JJ Celotta, RJ AF Bradley, CC Anderson, WR McClelland, JJ Celotta, RJ TI Nanofabrication via atom optics SO APPLIED SURFACE SCIENCE LA English DT Article; Proceedings Paper CT International Symposium on Nano-Scale Modification of Surfaces CY MAY 28-30, 1998 CL CTR JAPANESE AART & TECHNOL MANGGHA, KRAKOW, POLAND HO CTR JAPANESE AART & TECHNOL MANGGHA DE atom optics; atom lithography; laser-focused atomic deposition; nanostructures; nanofabrication; chromium ID DEPOSITION; LIGHT; LITHOGRAPHY; BEAM AB Owing to the continuing reduction in the scale of microelectronic and micromagnetic technology, new microfabrication methods are constantly being explored. This is particularly true in the case of nanostructure fabrication. Here, the phenomenon of optical diffraction limits the resolution obtainable by exposing a photoresist to a pattern of light, as is done in conventional lithography. We are investigating a different paradigm. Since both light and matter can be thought of as waves, instead of focusing light waves with objects made of matter, why not focus matter waves with objects made of light? To accomplish this we use lasers to form lenses from optical waves. These lenses focus a beam of neutral atoms prior to the atom's deposition on a silicon substrate. In this way, we have fabricated chromium structures consisting of thousands of parallel lines or millions of dots with dimensions as small as 28 nanometers. We describe the basis of this new technology, present examples of its application to date, detail its advantages and limitations, and discuss the future of optical nanostructure fabrication. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP McClelland, JJ (reprint author), Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. EM jabez@epg.nist.gov RI McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 NR 20 TC 26 Z9 27 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAR PY 1999 VL 141 IS 3-4 BP 210 EP 218 DI 10.1016/S0169-4332(98)00507-8 PG 9 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 177DG UT WOS:000079191700003 ER PT J AU McLaughlin, SM Faisal, M AF McLaughlin, SM Faisal, M TI A comparison of diagnostic assays for detection of Perkinsus spp. in the softshell clam Mya arenaria SO AQUACULTURE LA English DT Article DE Perkinsus spp.; thioglycolate assay; softshell clam; infection intensity; histopathology; tissue comparison ID N-SP APICOMPLEXA; RUDITAPES-DECUSSATUS AB Perkinsus spp. infections are increasing in prevalence and intensity in softshell clams Mya arenaria, a commercially and ecologically important bivalve of the Chesapeake Bay. In the present study, the gills, labial palps, rectal tissue, and hemolymph from softshell clams were compared for their suitability in thioglycolate diagnosis of Perkinsus spp. infection. Gill and palp tissues were more sensitive than either rectal tissue or hemolymph for detecting light infections. Rectal tissues became effective measures of parasite burdens as infections increased in intensity. Hemolymph samples were positive only in advanced infections. Further examination of paraffin-embedded tissue sections from lightly infected clams resulted in false negatives when compared with gill or palp thioglycolate assays. Hence, the use of both rectal and gill thioglycolate assays are recommended for routine diagnosis of softshell clam Perkinsus spp. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Marine Fisheries Serv, Cooperat Oxford Lab, Oxford, MD 21654 USA. Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. RP McLaughlin, SM (reprint author), Natl Marine Fisheries Serv, Cooperat Oxford Lab, 904 S Morris St, Oxford, MD 21654 USA. EM shawn.mclaughlin@noaa.gov NR 17 TC 13 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD MAR 1 PY 1999 VL 172 IS 1-2 BP 197 EP 204 DI 10.1016/S0044-8486(98)00447-5 PG 8 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 170AX UT WOS:000078783900011 ER PT J AU Persily, AK AF Persily, AK TI Myths about building envelopes SO ASHRAE JOURNAL LA English DT Article AB It is often assumed that commercial and institutional buildings are fairly airtight and that envelope air leakage does not have a significant impact on energy consumption and indoor air quality in these buildings. Furthermore, it is assumed that more recently constructed buildings are tighter than older buildings. However, very little data is available on the airtightness of building envelopes in commercial and institutional buildings. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Persily, AK (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 21 TC 19 Z9 19 U1 0 U2 2 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 0001-2491 J9 ASHRAE J JI ASHRAE J. PD MAR PY 1999 VL 41 IS 3 BP 39 EP + PG 7 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 235EN UT WOS:000082527200011 ER PT J AU Brandt, JC Heap, SR Beaver, EA Boggess, A Carpenter, KG Ebbets, DC Hutchings, JB Jura, M Leckrone, DS Linsky, JL Maran, SP Savage, BD Smith, AM Trafton, LM Walter, FM Weymann, RJ Proffitt, CR Wahlgren, GM Johansson, SG Nilsson, H Brage, T Snow, M Ake, TB AF Brandt, JC Heap, SR Beaver, EA Boggess, A Carpenter, KG Ebbets, DC Hutchings, JB Jura, M Leckrone, DS Linsky, JL Maran, SP Savage, BD Smith, AM Trafton, LM Walter, FM Weymann, RJ Proffitt, CR Wahlgren, GM Johansson, SG Nilsson, H Brage, T Snow, M Ake, TB TI A Goddard High Resolution Spectrograph atlas of echelle observations of the HgMn star chi Lupi SO ASTRONOMICAL JOURNAL LA English DT Article DE atlases; stars : chemically peculiar; stars : individual (chi Lupi) ID OSCILLATOR-STRENGTHS; HYPERFINE-STRUCTURE; HEAVY-ELEMENTS; TL-II; ABUNDANCE; TRANSITIONS; SPECTRA; GHRS; LINES; HST AB Observations of the ultra-sharp-lined, chemically peculiar star chi Lupi taken by the Goddard High Resolution Spectrograph in echelle mode are presented. Thirty-six intervals of the spectral region between 1249 and 2688 Angstrom are covered with resolving powers in the range 75,000-93,000. Line identifications are provided, and the observed spectra are compared with synthetic spectra calculated using the SYNTHE program and associated line lists with changes to the line lists. The significance of these spectra for the chi Lupi Pathfinder Project and the closely related atomic physics effort is discussed in a companion paper. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Ball Aerosp & Technol Corp, Boulder, CO 80306 USA. Dominion Astrophys Observ, Victoria, BC V8X 4M6, Canada. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Space Sci Directorate, Greenbelt, MD 20771 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. SUNY Stony Brook, Dept Earth & Space Sci, Astron Program, Stony Brook, NY 11794 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. NASA, Goddard Space Flight Ctr, Sci Programs, Comp Sci Corp, Greenbelt, MD 20771 USA. Univ Lund, Dept Phys, S-22100 Lund, Sweden. RI heap, sara/E-2237-2012; Carpenter, Kenneth/D-4740-2012 NR 50 TC 35 Z9 35 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 1999 VL 117 IS 3 BP 1505 EP 1548 DI 10.1086/300753 PG 44 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 187KZ UT WOS:000079786900035 ER PT J AU Mac Low, MM Ferrara, A AF Mac Low, MM Ferrara, A TI Starburst-driven mass loss from dwarf galaxies: Efficiency and metal ejection SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : starburst; galaxies : stellar content; hydrodynamics; supernovae : general ID RADIO-CONTINUUM OBSERVATIONS; ENHANCED GALACTIC WINDS; DARK-MATTER HALOS; X-RAY; INTERSTELLAR-MEDIUM; STAR-FORMATION; EVOLUTION; GAS; SUPERBUBBLES; EXPLOSIONS AB We model the effects of repeated supernova (SN) explosions from starbursts in dwarf galaxies on the interstellar medium of these galaxies, taking into account the gravitational potential of their dominant dark matter halos. We explore SN rates from one every 30,000 yr to one every 3 Myr, equivalent to steady mechanical luminosities of L = 0.1-10 x 10(38) ergs s(-1), occurring in dwarf galaxies with gas masses M-g = 10(6)-10(9) M.. We address in detail, both analytically and numerically, the following three questions : 1. When do the SN ejects blow out of the disk of the galaxy? 2. When blowout occurs, what fraction of the interstellar gas is blown away, escaping the potential of the galactic halo? 3. What happens to the metals ejected from the massive stars of the starburst? Are they retained or blown away? We give quantitative results for when blowout will or will not occur in galaxies with 10(6) less than or equal to M-g less than or equal to 10(9) M.. Surprisingly, we find that the mass ejection efficiency is very low for galaxies with mass M-g greater than or equal to 10(7) M.. Only galaxies with M-g less than or similar to 10(6) M. have their interstellar gas blown away, and then virtually independently of L. On the other hand, metals from the SN ejecta are accelerated to velocities larger than the escape speed from the galaxy far more easily than the gas. We find that for L-38 = 1, only about 30% of the metals are retained by a 10(9) M. galaxy, and virtually none by smaller galaxies. We discuss the implications of our results for the evolution, metallicity, and observational properties of dwarf galaxies. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. RP Mac Low, MM (reprint author), Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany. OI Mac Low, Mordecai-Mark/0000-0003-0064-4060 NR 52 TC 724 Z9 725 U1 0 U2 3 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 1 PY 1999 VL 513 IS 1 BP 142 EP 155 DI 10.1086/306832 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 194MM UT WOS:000080197500009 ER PT J AU Vangel, MG Rukhin, AL AF Vangel, MG Rukhin, AL TI Maximum likelihood analysis for heteroscedastic one-way random effects ANOVA in interlaboratory studies SO BIOMETRICS LA English DT Article DE collaborative study; hierarchical model; noninformative prior; profile likelihood; weighted mean AB This article presents results for the maximum likelihood analysis of several groups of measurements made on the same quantity. Following Cochran (1937, Journal of the Royal Statistical Society 4(Supple), 102-118; 1954, Biometrics 10, 101-129; 1980, in Proceedings of the 25th Conference on the Design of Experiments in Army Research, Development and Testing, 21-33) and others, this problem is formulated as a one-way unbalanced random-effects ANOVA with unequal within-group variances. A reparametrization of the likelihood leads to simplified computations easier identification and interpretation of multimodality of the likelihood, and (through a non-informative-prior Bayesian approach) approximate confidence regions for the mean and between-group variance. C1 Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Math & Stat, Catonsville, MD 21228 USA. RP Vangel, MG (reprint author), Natl Inst Stand & Technol, Stat Engn Div, Bldg 820,Room 353,820 W Diamond Ave, Gaithersburg, MD 20899 USA. NR 17 TC 35 Z9 36 U1 2 U2 6 PU INTERNATIONAL BIOMETRIC SOC PI WASHINGTON PA 1441 I ST, NW, SUITE 700, WASHINGTON, DC 20005-2210 USA SN 0006-341X J9 BIOMETRICS JI Biometrics PD MAR PY 1999 VL 55 IS 1 BP 129 EP 136 DI 10.1111/j.0006-341X.1999.00129.x PG 8 WC Biology; Mathematical & Computational Biology; Statistics & Probability SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology; Mathematics GA 183RK UT WOS:000079567100015 PM 11318146 ER PT J AU Nappo, CJ Johansson, PE AF Nappo, CJ Johansson, PE TI Preface SO BOUNDARY-LAYER METEOROLOGY LA English DT Editorial Material C1 NOAA, ERL, ARL, Oak Ridge, TN USA. FOA, Umea, Sweden. RP Nappo, CJ (reprint author), NOAA, ERL, ARL, Oak Ridge, TN USA. NR 0 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 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD MAR PY 1999 VL 90 IS 3 BP 343 EP 344 DI 10.1023/A:1026458406979 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 196BR UT WOS:000080289600001 ER PT J AU Nappo, CJ Johansson, PE AF Nappo, CJ Johansson, PE TI Summary of the Lovanger International workshop on turbulence and diffusion in the stable planetary boundary layer SO BOUNDARY-LAYER METEOROLOGY LA English DT Article ID LARGE-EDDY SIMULATION; GRAVITY-WAVES; MODEL; DISPERSION; FOREST; FLOW AB A workshop on the stable planetary boundary layer (PBL) was held on 21-24 October 1997 at Lovanger, a small town about 80 km north of Umea, Sweden. Thirty-five scientist representing eight countries participated in the meeting, which was arranged by the US Army Research Office, the Swedish Defence Research Establishment, the US National Oceanic and Atmospheric Administration's Air Resources Laboratory, and the Meteorology Department of Uppsala University. Topics addressed included the very stable boundary layer, gravity wave/turbulence interactions, modeling the stable boundary layer, future observations and new measurement techniques, the role of the condensation (fog) and radiative flux divergence, and atmospheric diffusion. Invited papers appear in this special issue. Workshop discussions, informal presentations, and specific recommendations are summarized. Workshop participants and organizers are presented in Appendix A. C1 NOAA, Air Resources Lab, Div Atmospher Turbulence & Diffus, Oak Ridge, TN 37830 USA. Def Res Estab, Dept NBC Def, S-90182 Umea, Sweden. RP Nappo, CJ (reprint author), NOAA, Air Resources Lab, Div Atmospher Turbulence & Diffus, 456 S Illinois Ave, Oak Ridge, TN 37830 USA. NR 41 TC 15 Z9 15 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD MAR PY 1999 VL 90 IS 3 BP 345 EP 374 DI 10.1023/A:1026458421572 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 196BR UT WOS:000080289600011 ER PT J AU Rao, KS AF Rao, KS TI Lagrangian stochastic modeling of dispersion in the stable boundary layer SO BOUNDARY-LAYER METEOROLOGY LA English DT Article; Proceedings Paper CT International Workshop on Turbulence and Diffusion in the Stable Planetary Boundary Layer CY OCT 21-24, 1997 CL LOVANGER, SWEDEN SP US Army Res Off, Swedish Defence Res Establishment, US NOAA Air Resources Lab, Swedish Acad Sci, Stockholm Univ Int Meteorol Inst DE dispersion; Lagrangian modeling; stable boundary layer ID FLOWS; TRAJECTORIES AB Lagrangian stochastic models are well-suited for modeling dispersion in the stable boundary layer, especially in complex terrain. This note briefly describes the formulations and application of a Lagrangian stochastic model to predict dispersion of tracers released within nocturnal drainage flows. C1 NOAA, ARL, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. RP Rao, KS (reprint author), NOAA, ARL, Atmospher Turbulence & Diffus Div, POB 2456, Oak Ridge, TN 37831 USA. NR 6 TC 5 Z9 5 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0006-8314 J9 BOUND-LAY METEOROL JI Bound.-Layer Meteor. PD MAR PY 1999 VL 90 IS 3 BP 541 EP 549 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 196BR UT WOS:000080289600010 ER PT J AU Moles, A AF Moles, A TI Parasitism, feeding rate, and hydrocarbon uptake of pink shrimp Pandalus borealis fed a crude oil contaminated diet SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID PRINCE-WILLIAM-SOUND; EXXON-VALDEZ; PETROLEUM-HYDROCARBONS; SEDIMENTS; SEAWATER; SPILL; FOOD C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Moles, A (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 12 TC 7 Z9 7 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD MAR PY 1999 VL 62 IS 3 BP 259 EP 265 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 176DW UT WOS:000079136500004 PM 10085167 ER PT J AU Bond, AB Stephens, JS Pondella, DJ Allen, MJ Helvey, M AF Bond, AB Stephens, JS Pondella, DJ Allen, MJ Helvey, M TI A method for estimating marine habitat values based on fish guilds, with comparisons between sites in the Southern California Bight SO BULLETIN OF MARINE SCIENCE LA English DT Article ID BOTTOM KELP FOREST; SAN-ONOFRE; ABUNDANCE; REEF; ASSEMBLAGES; PATTERNS; COAST AB Habitat valuation is an essential tool for tracking changes in habitat quality and in adjudicating environmental mitigation. All current methods for estimating habitat values of coastal marine sites rely heavily on the opinion of experts or on data variables that can readily be manipulated to influence the outcome. As a result, unbiased, quantitative comparisons between the values of different marine habitats are generally unavailable. We report here on a robust, objective technique for the valuation of marine habitats that makes use of data that are commonly gathered in surveys of marine fish populations: density, fidelity, and mean size. To insure comparability across habitats, these variables are assessed for guilds of fishes, rather than for single species. The product of the three guild-based parameters is transformed to its square root and then summed across all guilds in the habitat, yielding a single measure of habitat value for each site surveyed. To demonstrate the usefulness of this approach, we have analyzed data from existing surveys of 13 marine sites in the Southern California Eight, encompassing 98 fish species from 23 guilds. For seven of the sites, it was possible to develop estimates of the confidence interval of the habitat valuation, using a resampling technique. Variance estimates from resampling in one habitat mirrored those derived from analysis of annual variation. The resultant ranking of habitat types was: kelp beds > shallow artificial reefs > wetlands > protected shallow waters (soft bottom) > shallow open coastal sand (depth <30 m) > soft bottom habitat on the continental shelf (30 m < depth <200 m) > soft bottom habitat on the continental slope (depth >200 m). Although our data sets were restricted to Southern California, similar data could be obtained from any reasonably well-studied marine environment. The guild-based valuation technique may, therefore, be broadly applicable to the analysis of other marine ecosystems. C1 Occidental Coll, Vantuna Res Grp, Zool Lab, Los Angeles, CA 90041 USA. Univ Nebraska, Sch Biol Sci, Lincoln, NE 68588 USA. So Calif Coastal Water Res Project, Westminster, CA 92683 USA. Natl Marine Fisheries Serv, Santa Rosa, CA 95404 USA. RP Occidental Coll, Vantuna Res Grp, Zool Lab, 1600 Campus Rd, Los Angeles, CA 90041 USA. EM abond@unl.edu; stephens2@earthlink.net; pondella@oxy.edu NR 35 TC 20 Z9 20 U1 2 U2 14 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 EI 1553-6955 J9 B MAR SCI JI Bull. Mar. Sci. PD MAR PY 1999 VL 64 IS 2 BP 219 EP 242 PG 24 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 190UG UT WOS:000079983200004 ER PT J AU Vivekanandan, J Zrnic, DS Ellis, SM Oye, R Ryzhkov, AV Straka, J AF Vivekanandan, J Zrnic, DS Ellis, SM Oye, R Ryzhkov, AV Straka, J TI Cloud microphysics retrieval using S-band dual-polarization radar measurements SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID POLARIMETRIC RADAR; PRECIPITATION; HAIL; IDENTIFICATION; HAILSTORM; RAIN; ICE AB Recent studies have shown the utility of polarimetric radar observables and derived fields for discrimination of hydrometeor particle types. Because the values of the radar observables that delineate different particle types overlap and are not sharply defined, the problem is well suited for a fuzzy logic approach. In this preliminary study the authors have developed and implemented a fuzzy logic algorithm for hydrometeor particle identification that is simple and efficient enough to run in real time for operational use. Although there are no in situ measurements available for this particle-type verification, the initial results are encouraging. Plans for further verification and optimization of the algorithm are described. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Norman, OK 73019 USA. RP Vivekanandan, J (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM vivek@ucar.edu NR 23 TC 212 Z9 219 U1 0 U2 10 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 1999 VL 80 IS 3 BP 381 EP 388 DI 10.1175/1520-0477(1999)080<0381:CMRUSB>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 181UD UT WOS:000079460100001 ER PT J AU Zrnic, DS Ryzhkov, AV AF Zrnic, DS Ryzhkov, AV TI Polarimetry for weather surveillance radars SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID DIFFERENTIAL REFLECTIVITY RADAR; POLARIZATION RADAR; RAIN; PRECIPITATION; PHASE; HAIL; THUNDERSTORMS; ORIENTATION; SYSTEMS AB This paper is an overview of weather radar polarimetry emphasizing surveillance applications. The following potential benefits to operations are identified: improvement of quantitative precipitation measurements, discrimination of hail from rain with possible determination of sizes, identification of precipitation in winter storms, identification of electrically active storms, and distinction of biological scatterers (birds vs insects). Success in rainfall measurements is attributed to unique properties of differential phase. Referrals to fields of various polarimetric variables illustrate the signatures associated with different phenomena. It is argued that classifying hydrometeors is a necessary step prior to proper quantification of the water substance. The promise of polarimetry to accomplish classification is illustrated with an application to a hailstorm. C1 Natl Severe Storms Lab, Doppler Radar & Remote Sensing Branch, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Zrnic, DS (reprint author), Natl Severe Storms Lab, Doppler Radar & Remote Sensing Branch, 1313 Halley Circle, Norman, OK 73069 USA. NR 39 TC 173 Z9 176 U1 1 U2 12 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 1999 VL 80 IS 3 BP 389 EP 406 DI 10.1175/1520-0477(1999)080<0389:PFWSR>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 181UD UT WOS:000079460100002 ER PT J AU Hock, TF Franklin, JL AF Hock, TF Franklin, JL TI The NCAR GPS dropwindsonde SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID IMPACT AB The National Center for Atmospheric Research (NCAR), in a joint effort with the National Oceanic and Atmospheric Administration (NOAA) and the German Aerospace Research Establishment, has developed a dropwindsonde based on the Global Positioning System (GPS) satellite navigation. The NCAR GPS dropwindsonde represents a major advance in both accuracy and resolution for atmospheric measurements over data-sparse oceanic areas of the globe, providing wind accuracies of 0.5-2.0 m s(-1) with a vertical resolution of similar to 5 m. One important advance over previous generations of sondes is the ability to measure surface (10 m) winds. The new dropwindsonde has already been used extensively in one major international research field experiment (Fronts and Atlantic Storm Track Experiment), in operational and research hurricane flights from NOAA's National Weather Service and Hurricane Research Division, during NCAR's SNOWBAND experiment, and in recent CALJET and NORPEX El Nino experiments. The sonde has been deployed from a number of different aircraft, including NOAA's WP-3Ds and new Gulfstream IV jet, the Air Force C-130s, NCAR's Electra, and a leased Lear-36. This paper describes the characteristics of the new dropwindsonde and its associated aircraft data system, details the accuracy of its measurements, and presents examples from its initial applications. C1 NOAA, NWS, Trop Predict Ctr, Hurricane Res Div, Miami, FL 33165 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Franklin, JL (reprint author), NOAA, NWS, Trop Predict Ctr, Hurricane Res Div, 11691 SW 17 St, Miami, FL 33165 USA. NR 12 TC 206 Z9 210 U1 0 U2 5 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 1999 VL 80 IS 3 BP 407 EP 420 DI 10.1175/1520-0477(1999)080<0407:TNGD>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 181UD UT WOS:000079460100003 ER PT J AU Aberson, SD Franklin, JL AF Aberson, SD Franklin, JL TI Impact on hurricane track and intensity forecasts of GPS dropwindsonde observations from the first-season flights of the NOAA Gulfstream-IV jet aircraft SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SYSTEM; MODEL; PREDICTION; NMC AB In 1997, the Tropical Prediction Center (TPC) began operational Gulfstream-IV jet aircraft missions to improve the numerical guidance for hurricanes threatening the continental United States, Puerto Rico, and the Virgin Islands. During these missions, the new generation of Global Positioning System dropwindsondes were released from the aircraft at 150-200-km intervals along the flight track in the environment of the tropical cyclone to obtain profiles of wind, temperature, and humidity from flight level to the surface. The observations were ingested into the global model at the National Centers for Environmental Prediction, which subsequently serves as initial and boundary conditions to other numerical tropical cyclone models. Because of a lack of tropical cyclone activity in the Atlantic basin, only five such missions were conducted during the inaugural 1997 hurricane season. Due to logistical constraints, sampling in all quadrants of the storm environment was accomplished in only one of the five cases during 1997. Nonetheless, the dropwindsonde observations improved mean track forecasts from the Geophysical Fluid Dynamics Laboratory hurricane model by as much as 32%, and the intensity forecasts by as much as 20% during the hurricane watch period (within 48 h of projected landfall). Forecasts from another dynamical tropical cyclone model (VICBAR) also showed modest improvements with the dropwindsonde observations. These improvements, if confirmed by a larger sample, represent a large step toward the forecast accuracy goals of TPC. The forecast track improvements are as large as those accumulated over the past 20-25 years, and those for forecast intensity provide further evidence that better synoptic-scale data can lead to more skillful dynamical tropical cyclone intensity forecasts. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Aberson, SD (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. EM aberson@aoml.noaa.gov RI Aberson, Sim/C-4891-2013 OI Aberson, Sim/0000-0002-3670-0100 NR 23 TC 80 Z9 84 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 MAR PY 1999 VL 80 IS 3 BP 421 EP 427 DI 10.1175/1520-0477(1999)080<0421:IOHTAI>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 181UD UT WOS:000079460100004 ER PT J AU Hamilton, K AF Hamilton, K TI Comment on "Observations of tropical stratospheric winds before World War II" - Reply SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Letter C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08544 USA. RP Hamilton, K (reprint author), Princeton Univ, NOAA, GFDL, Princeton, NJ 08544 USA. NR 0 TC 0 Z9 0 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 1999 VL 80 IS 3 BP 473 EP 473 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 181UD UT WOS:000079460100009 ER PT J AU Easterling, DR AF Easterling, DR TI Development of regional climate scenarios using a downscaling approach SO CLIMATIC CHANGE LA English DT Article ID GENERAL-CIRCULATION MODEL; OCEAN ATMOSPHERE MODEL; MINIMUM TEMPERATURE; TRANSIENT RESPONSES; GRADUAL CHANGES; UNITED-STATES; VARIABILITY; PRECIPITATION; TRENDS; CO2 AB As the debate on potential climate change continues, it is becoming increasingly clear that the main concerns to the general public are the potential impacts of a change in the climate on societal and biophysical systems. In order to address these concerns researchers need realistic, plausible scenarios of climate change suitable for use in impacts analysis. It is the purpose of this paper to present a downscaling method useful for developing these types of scenarios that are grounded in both General Circulation Model simulations of climate change, and in situ station data. Free atmosphere variables for four gridpoints over the Missouri, Iowa, Nebraska, Kansas (MINK) region from both control and transient simulations from the GFDL General Circulation Model were used with thirty years of nearby station data to generate surface maximum and minimum air temperatures and precipitation. The free atmosphere variables were first subject to a principal components analysis with the principal component (PC) scores used in a multiple regression to relate the upper-air variables to surface temperature and precipitation. Coefficients from the regression on station data were then used with PC scores from the model simulations to generate maximum and minimum temperature and precipitation. The statistical distributions of the downscaled temperatures and precipitation for the control run are compared with those from the observed station data. Results for the transient run are then examined. Lastly, annual time series of temperature for the downscaling results show less warming over the period of the transient simulation than the time series produced directly from the model. C1 Natl Climat Data Ctr, Asheville, NC 28801 USA. RP Easterling, DR (reprint author), Natl Climat Data Ctr, Fed Bldg,151 Patton Ave, Asheville, NC 28801 USA. NR 22 TC 45 Z9 46 U1 0 U2 2 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 MAR PY 1999 VL 41 IS 3-4 BP 615 EP 634 DI 10.1023/A:1005425613593 PG 20 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 194JM UT WOS:000080189100015 ER PT J AU Sokol, GM Van Meurs, KP Wright, LL Rivera, O Thorn, WJ Chu, PM Sams, RL AF Sokol, GM Van Meurs, KP Wright, LL Rivera, O Thorn, WJ Chu, PM Sams, RL TI Nitrogen dioxide formation during inhaled nitric oxide therapy SO CLINICAL CHEMISTRY LA English DT Article ID PERSISTENT PULMONARY-HYPERTENSION; RESPIRATORY-DISTRESS-SYNDROME; DIODE-LASER ABSORPTION; NEWBORN; OXYGENATION; AIR AB Background: Nitrogen dioxide (NO2) is a toxic byproduct of inhalation therapy with nitric oxide (NO). The rate of NO2 formation during NO therapy is controversial. Methods: The formation of NO2 was studied under dynamic flows emulating a base case NO ventilator mixture containing 80 ppm NO in a 90% oxygen matrix. The difficulty in measuring NO2 concentrations below 2 ppm accurately was overcome by the use of tunable diode laser absorption spectroscopy. Results: Using a second-order model, the rate constant, k, for NO2 formation was determined to be (1.19 +/- 0.11) x 10(-11) ppm(-2) s(-1), which is in basic agreement with evaluated data from atmospheric literature. Conclusions: Inhaled NO can be delivered safely in a well-designed, continuous flow neonatal ventilatory circuit, and NO2 formation can be calculated reliably using the rate constant and circuit dwell time. (C) 1999 American Association for Clinical Chemistry. C1 Indiana Univ, Dept Pediat, Indianapolis, IN 46202 USA. Stanford Univ, Med Ctr, Dept Pediat, Stanford, CA 94304 USA. NICHHD, Neonatal Network, Bethesda, MD 20892 USA. Childrens Hosp, Natl Med Ctr, Dept Biomed Engn, Washington, DC 20010 USA. NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Sokol, GM (reprint author), Indiana Univ, Sch Med, Div Neonatal Perinatal MEd, 702 Barnhill Dr,Room rr-208, Indianapolis, IN 46202 USA. EM gsokol@iupui.edu FU NICHD NIH HHS [U10 HD27856] NR 25 TC 23 Z9 25 U1 0 U2 1 PU AMER ASSOC CLINICAL CHEMISTRY PI WASHINGTON PA 2101 L STREET NW, SUITE 202, WASHINGTON, DC 20037-1526 USA SN 0009-9147 J9 CLIN CHEM JI Clin. Chem. PD MAR PY 1999 VL 45 IS 3 BP 382 EP 387 PG 6 WC Medical Laboratory Technology SC Medical Laboratory Technology GA 173KE UT WOS:000078979100009 PM 10053039 ER PT J AU Blevins, LG Gore, JP AF Blevins, LG Gore, JP TI Computed structure of low strain rate partially premixed CH4/air counterflow flames: Implications for NO formation SO COMBUSTION AND FLAME LA English DT Article ID DIFFUSION FLAMES; JET FLAMES; LAMINAR; FUEL; EMISSION; TEMPERATURE; COMBUSTION; CHEMISTRY AB Results from computations of low strain rate, partially premixed methane/air counterflow flames are reported. The Oppdif computer code was used with GRI-Mech 2.11 to obtain the results. When the fuel-side equivalence ratio (Phi(B)) is above 2.5, the present flame structure can be described as a CH4/air premixed flame merged with a CO/H-2/air nonpremixed flame. When Phi(B) is below 2.5, the two flame zones exist on opposite sides of the stagnation plane, and the CO/H-2/air nonpremixed flame is characterized by hydrocarbon concentration peaks on its fuel-side edge. Broad NO destruction regions, caused primarily by CHi + NO reactions, exist between the resulting double hydrocarbon concentration peaks. The fuel-side equivalence ratio is the most important indicator of how rapidly NO is destroyed relative to how rapidly it is formed, and NO destruction reactions are more important in pure diffusion flames than in partially premixed flames for the present low strain rate computations. (C) 1998 by The Combustion Institute. C1 Purdue Univ, Sch Mech Engn, Thermal Sci & Prop Ctr, W Lafayette, IN 47907 USA. RP Blevins, LG (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Bldg 224,Room B360, Gaithersburg, MD 20899 USA. NR 52 TC 30 Z9 30 U1 0 U2 2 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 1999 VL 116 IS 4 BP 546 EP 566 DI 10.1016/S0010-2180(98)00059-5 PG 21 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 153XV UT WOS:000077859400005 ER PT J AU Dennis, RL Arnold, JR Tonnesen, GS Li, YH AF Dennis, RL Arnold, JR Tonnesen, GS Li, YH TI A new response surface approach for interpreting Eulerian air quality model sensitivities SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article; Proceedings Paper CT 2nd International Symposium on Sensitivity Analysis of Model Output (SAMO 98) CY APR 19-22, 1998 CL VENICE, ITALY DE sensitivity analysis; ozone (O-3); nitrogen oxides (NOx); RADM; input uncertainties; emissions reductions ID PHASE CHEMICAL MECHANISM; ACID DEPOSITION MODEL; UNCERTAINTY ANALYSIS; OZONE AB The Regional Acid Deposition Model (RADM) was used in a sensitivity study at 80 km and 20 km grid resolutions to simulate urban and regional tropospheric conditions in the eastern U.S. for the time period 19 July to 12 August 1988. Using one-at-a-time (OAT) sensitivity perturbations and a mini-global analysis we varied three model inputs in the range of their known uncertainties: mixing height; emissions of nitrogen oxides (NO,) and volatile organic compounds (VOC); and the rate constant for the reaction OH + NO2 --> HNO3. Two measures, ozone concentration ([O-3]) and the ratio [O-3]/[NOx], were used to assess the photochemical system's sensitivity response on an O-3 response surface. We find that: (1) these input uncertainties change the system's state in different ways, altering either the [O-3] or the system's response to emissions reductions, or changing both responses together; (2) the [O-3]/[NOx] measure successfully predicts the direction and relative degree of change in the system state while [O-3] does not; and (3) for most of the days and locations we have examined, the system's responses to uncertainties simulated OAT are nearly additive when compared with the mini-global case, and that both of the sensitivity measures we assessed correctly tracked this additivity. We conclude that incorporating the [O-3]/[NOx] ratio is a significant first step in constructing a useful sensitivity "vector" for understanding systems-level changes in the model. However, additional measures that can successfully track the change of shape of the response surface are still needed. (C) 1999 Elsevier Science B.V. C1 NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27709 USA. RP Dennis, RL (reprint author), US EPA, Natl Exposure Res Lab, Modeling Div, MD-80,79 TW Alexander Dr,Bldg 4201, Res Triangle Pk, NC 27709 USA. NR 23 TC 6 Z9 7 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD MAR PY 1999 VL 117 IS 1-2 BP 99 EP 112 DI 10.1016/S0010-4655(98)00167-2 PG 14 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 179TB UT WOS:000079344200011 ER PT J AU Beichl, I Sullivan, F AF Beichl, I Sullivan, F TI The importance of importance sampling SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Editorial Material C1 NIST, Comp & Appl Math Lab, Gaithersburg, MD 20899 USA. IDA, Ctr Comp Sci, Bowie, MD 20715 USA. RP Beichl, I (reprint author), NIST, Comp & Appl Math Lab, Gaithersburg, MD 20899 USA. NR 1 TC 19 Z9 21 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD MAR-APR PY 1999 VL 1 IS 2 BP 71 EP 73 DI 10.1109/5992.753049 PG 5 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 180WG UT WOS:000079407700013 ER PT J AU Carls, MG Rice, SD Hose, JE AF Carls, MG Rice, SD Hose, JE TI Sensitivity of fish embryos to weathered crude oil: Part I. Low-level exposure during incubation causes malformations, genetic damage, and mortality in larval Pacific herring (Clupea pallasi) SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE herring larvae; morphological damage; genetic damage; polynuclear aromatic hydrocarbons; Exxon Valdez oil spill ID EXXON-VALDEZ OIL; PRINCE-WILLIAM-SOUND; JUVENILE PINK SALMON; PETROLEUM-HYDROCARBONS; SPILL; ALASKA; SEDIMENTS; GROWTH; ABUNDANCE; SURVIVAL AB Pacific herring eggs were exposed for 16 d to weathered Alaska North Slope crude oil. Exposure to an initial aqueous concentration of 0.7 parts per billion (ppb) polynuclear aromatic hydrocarbons (PAHs) caused malformations, genetic damage, mortality, and decreased size and inhibited swimming. Total aqueous PAH concentrations as low as 0.4 ppb caused sublethal responses such as yolk sac edema and immaturity consistent with premature hatching. Responses to less weathered oil, which had relatively lower proportions of high molecular weight PAH, generally paralleled those of more weathered oil, but lowest observed effective concentrations (LOECs) were higher (9.1 ppb), demonstrating the importance of composition. The LOEC for more weathered oil (0.4 ppb) was similar to that observed in pink salmon (1.0 ppb), a species with a very different development rate; by inference, other species may be similarly sensitive to weathered oil. Our methods simulated conditions observed in Prince William Sound (PWS) following the Exxon Valdez oil (EVO) spill. Biological effects were identical to those observed in embryolarval herring from PWS in 1989 and support the conclusion that EVO caused significant damage to herring in PWS. Previous demonstration by our laboratory that most malformed or precocious larvae die corroborates the decreased larval production measured after the spill. C1 Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. Occidental Coll, Los Angeles, CA 90041 USA. RP Carls, MG (reprint author), Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 49 TC 220 Z9 224 U1 11 U2 85 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAR PY 1999 VL 18 IS 3 BP 481 EP 493 DI 10.1897/1551-5028(1999)018<0481:SOFETW>2.3.CO;2 PG 13 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 167WX UT WOS:000078658100017 ER PT J AU Heintz, RA Short, JW Rice, SD AF Heintz, RA Short, JW Rice, SD TI Sensitivity of fish embryos to weathered crude oil: Part II. Increased mortality of pink salmon (Oncorhynchus gorbuscha) embryos incubating downstream from weathered Exxon Valdez crude oil SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE toxicity; pink salmon; Exxon Valdez; polynuclear aromatic hydrocarbons; oil spill ID SEDIMENTS AB We incubated pink salmon embryos under three exposure conditions, direct contact with oil-coated gravel. effluent from oil-coated gravel, and direct contact with gravel coated with very weathered oil (VWO). Embryo mortalities and polynuclear aromatic hydrocarbon (PAH) accumulation in embryo tissues during the direct-contact and effluent exposure experiments were not significantly different, indicating that PAH accumulation was mediated by aqueous transport. Mortality rates for embryos exposed initially to a total PAH concentration (TPAH) of 1.0 ppb were significantly higher than controls when the PAH were derived from VWO. The same aqueous TPAH concentration failed to increase mortality rates when the PAH were derived from less weathered oil, indicating that toxicity of effluents from the VWO was primarily associated with the larger PAH. We conclude that water quality standards for TPAH above 1.0 ppb may fail to protect fish embryos. Further, pink salmon embryos incubating in Prince William Sound after the Exxon Valdez oil spill may have accumulated lethal concentrations of PAH from interstitial water that was contaminated when it percolated through oil reservoirs located upstream from salmon redds. C1 Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Heintz, RA (reprint author), Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM ron.heintz@noaa.gov NR 19 TC 170 Z9 174 U1 7 U2 56 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD MAR PY 1999 VL 18 IS 3 BP 494 EP 503 DI 10.1897/1551-5028(1999)018<0494:SOFETW>2.3.CO;2 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 167WX UT WOS:000078658100018 ER PT J AU Peacock, RD Bukowski, RW Markos, SH AF Peacock, RD Bukowski, RW Markos, SH TI Evaluation of passenger train car materials in the cone calorimeter SO FIRE AND MATERIALS LA English DT Article AB Recent advances in fire test methods and hazard analysis techniques make it useful to re-examine passenger train fire safety requirements. The use of test methods based on heat release rate (HRR), incorporated with fire modelling and hazard analysis, could permit the assessment of potential hazards under realistic fire conditions. The results of research directed at the evaluation of passenger train car interior materials in the cone calorimeter are presented. These measurements provide data necessary for fire modelling as well as quantitative data that can be used to evaluate the performance of component materials and assemblies. The cone calorimeter test data were also compared with test data resulting from individual bench-test methods specified in the FRA fire safety guidelines, The majority of the tested materials which meet the current FRA guidelines show comparable performance in the cone calorimeter. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. US Dept Transportat, Volpe Natl Transportat Syst Ctr, Cambridge, MA 02142 USA. RP Peacock, RD (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, A249-Bldg 224, Gaithersburg, MD 20899 USA. NR 19 TC 4 Z9 4 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0308-0501 J9 FIRE MATER JI Fire Mater. PD MAR-APR PY 1999 VL 23 IS 2 BP 53 EP 62 DI 10.1002/(SICI)1099-1018(199903/04)23:2<53::AID-FAM669>3.3.CO;2-9 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 215AJ UT WOS:000081359500001 ER PT J AU Ohlemiller, TJ Cleary, TG AF Ohlemiller, TJ Cleary, TG TI Upward flame spread on composite materials SO FIRE SAFETY JOURNAL LA English DT Article DE upward flame spread; composite materials AB Three existing models of upward flame spread were tested against intermediate-scale experiments on a vinyl ester/glass composite, Characterization of rate of heat release per unit area, needed as input to the models, was obtained at external radiant fluxes below the minimum for ignition by adaptation of a method due to Kulkarni. There are several limitations on the accuracy of the material characterization when applied to composites. Each of the flame spread models has definite limitations as well. Nevertheless, all three models produced predictions of spread behavior in sufficiently quantitative agreement with the experiments that they should prove useful for engineering analyses of flame spread potential, Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Ohlemiller, TJ (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 9 TC 11 Z9 13 U1 0 U2 2 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 MAR PY 1999 VL 32 IS 2 BP 159 EP 172 DI 10.1016/S0379-7112(98)00030-7 PG 14 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 168YL UT WOS:000078720700005 ER PT J AU Ohlemiller, TJ Shields, JR AF Ohlemiller, TJ Shields, JR TI The effect of surface coatings on fire growth over composite materials in a corner configuration SO FIRE SAFETY JOURNAL LA English DT Article DE surface coatings; composite materials AB Structural composites are vulnerable to fire in two respects: (1) their resin content may ignite and enable the spread of flames over the surface of the structure; (2) the resin may degrade from the heat of a localized fire exposure thus weakening the composite structure. The present study focuses mainly on the first issue, in particular, on the ability of various commercial coatings to prevent flame spread The second issue is examined briefly by applying thermocouples to the back surface of test specimens. Four commercial coatings have been tested over an unretarded vinyl ester/glass composite. In addition an uncoated phenolic/glass composite and a polyester/glass composite coated with a fire retarded resin were tested. In all cases the configuration was a 3.3 m high corner with a 53 cm square propane gas burner at its base, operated at 250 kW as the fire exposure. The results show that, with the proper choice of coating and coating thickness, fire growth can be suppressed quite effectively. Two of the coatings, applied at a substantial thickness, mere reasonably effective at slowing the penetration of heat to the back of the composite panels. The other coatings, much thinner in application, were notably less effective at slowing heat penetration. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Ohlemiller, TJ (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 21 TC 12 Z9 12 U1 0 U2 5 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 MAR PY 1999 VL 32 IS 2 BP 173 EP 193 DI 10.1016/S0379-7112(98)00031-9 PG 21 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 168YL UT WOS:000078720700006 ER PT J AU Mace, PM AF Mace, PM TI Current status and prognosis for marine capture fisheries SO FISHERIES LA English DT Editorial Material C1 Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. RP Mace, PM (reprint author), Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. NR 0 TC 11 Z9 11 U1 0 U2 0 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0363-2415 J9 FISHERIES JI Fisheries PD MAR PY 1999 VL 24 IS 3 BP 30 EP 30 PG 1 WC Fisheries SC Fisheries GA 173DL UT WOS:000078965900005 ER PT J AU Cole, J AF Cole, J TI Environmental conditions, satellite imagery, and clupeoid recruitment in the northern Benguela upwelling system SO FISHERIES OCEANOGRAPHY LA English DT Article DE clupeoids; environment; northern Benguela; recruitment; remote sensing; spatial analysis ID HYDROGRAPHIC FEATURES; FISH POPULATIONS; ECOSYSTEM; PILCHARD; SUCCESS; LARVAE AB The relationship between oceanographic conditions and clupeoid (pilchard, Sardinops sagax, and anchovy, Engraulis capensis) recruitment in the northern Benguela upwelling system was investigated from 1981 to 1987 using a time-series of mean weekly SST images. Two approaches were taken. The first involved correlating recruitment success with the number of weekly coastal 'SST events' above various cut-off temperatures during the main reproductive season. The second involved constructing a multiple regression model of recruitment success with two independent environmental variables: namely, the number of coastal 'SST events' greater than 19 degrees C, and an onshore retention index for the early life-history stages. The retention index was derived from a spatial time-series analysis of the SST images using principal components analysis. In general, pilchard recruitment showed a positive relationship with the 'number of SST events' whilst anchovy recruitment had a negative relationship; 1987 was an outlier year, during which there were exceptionally high levels of both pilchard and anchovy recruitment. The multiple regression R-2 values were high and significant for both species (pilchard R-2 = 0.88, anchovy R-2 = 0.96). The regression model also accounted for the 1987 outlier according to levels of onshore retention which, despite low inshore SSTs, were particularly high during the 1986/87 reproductive season. Although these results need to be validated with data from a longer time period, they show how satellite data might be used for predicting clupeoid recruitment success in the northern Benguela. C1 Commiss European Communities, Joint Res Ctr, Space Applicat Inst, Marine Environm Unit, I-21020 Ispra, VA, Italy. RP NOAA, NMFS, Pacific Fisheries Environm Lab, Pacific Grove, CA 93950 USA. EM jcole@pfeg.noaa.gov NR 41 TC 31 Z9 31 U1 0 U2 3 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1054-6006 EI 1365-2419 J9 FISH OCEANOGR JI Fish Oceanogr. PD MAR PY 1999 VL 8 IS 1 BP 25 EP 38 DI 10.1046/j.1365-2419.1999.00091.x PG 14 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 265EN UT WOS:000084228900003 ER PT J AU Sakuma, KM Ralston, S Roberts, DA AF Sakuma, KM Ralston, S Roberts, DA TI Diel vertical distribution of postflexion larval Citharichthys spp. and Sebastes spp. off central California SO FISHERIES OCEANOGRAPHY LA English DT Article DE Citharichthys; diel; distribution; MOCNESS; postflexion; pycnocline; Sebastes; vertical ID THERAGRA-CHALCOGRAMMA; WALLEYE POLLOCK; GENUS SEBASTES; MARINE FISHES; ICHTHYOPLANKTON; JUVENILES; OREGON; REGION AB The diel and spatial distributions of postflexion larval Citharichthys spp, and Sebastes spp, at 67 stations off central California were examined during March 1994 with a 10 m(2) MOCNESS during 24 h sampling operations. At each station, a CTD profiler with an attached PAR sensor was deployed to measure temperature, salinity, sigma(t), dynamic height, and ambient light levels at depth. Catches of C. sordidus, C. stigmaeus, unidentified Sebastes spp., and S. jordani were larger at night than during the day and crepuscular periods, probably because of net avoidance during the day and crepuscular periods, and (for Citharichthys spp;) vertical migration into the upper water column at night. C. sordidus and C. stigmaeus migrated vertically through the pycnocline on a diurnal cycle, while Sebastes spp, apparently remained in the mixed layer above the pycnocline at all times,No definitive patterns were observed between horizontal contours of temperature, salinity, and sigma(t) at depth and catches of any larvae. This was attributed to the relatively homogeneous spatial pattern in the water column above the pycnocline, where the majority of the fish occurred. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, Tiburon, CA 94920 USA. RP Sakuma, KM (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, 3150 Paradise Dr, Tiburon, CA 94920 USA. NR 29 TC 25 Z9 26 U1 2 U2 9 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 1999 VL 8 IS 1 BP 68 EP 76 DI 10.1046/j.1365-2419.1999.00088.x PG 9 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 265EN UT WOS:000084228900006 ER PT J AU Gnanadesikan, A AF Gnanadesikan, A TI A global model of silicon cycling: Sensitivity to eddy parameterization and dissolution SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID GENERAL-CIRCULATION MODEL; WORLD OCEAN; TRACER TRANSPORTS; BIOGENIC SILICA; NORTH-ATLANTIC; CARBON-DIOXIDE; SARGASSO SEA; BUDGET; SIMULATIONS; RADIOCARBON AB A simple model of silicon cycling has been embedded in a coarse-resolution ocean general circulation model. The modeled distribution of silicate was extremely sensitive to the parameterization of the effects of mesoscale eddies, and was somewhat sensitive to the distribution of dissolution within the water column. The modeled export flux of biogenic silica varied by a factor of 2 with respect to both the range of dissolution and eddy parameterizations. The best results were found when eddies were parameterized as mixing along isopycnals while simultaneously driving an advective flux so as to homogenize the depth of isopycnal surfaces (the so-called Gent-McWilliams parameterization). The Gent-McWilliams scheme produced the most realistic stratification field in the Southern Ocean, reducing vertical exchange and hence export fluxes of biogenic silica. This scheme did not solve the model's tendency to underpredict the formation of the North Atlantic Deep Water and to overpredict the importance of Antarctic source waters in the abyss, especially in the Atlantic. When used with a temperature-dependent dissolution scheme, this model predicted a global production of 89 Tmol yr(-1) with about 40% occurring in both the Southern Ocean and the tropics. In both the North Pacific and Southern Oceans, local silicate maxima are maintained by near-surface inflow of silicate with outflow at depth. The modeled production of biogenic silica showed little sensitivity to polar freshening when the Gent-McWilliams parameterization was used. The results emphasize the impact of including both the diffusive and advective effects of eddies, as in the Gent-McWilliams parameterization. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RP Gnanadesikan, A (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, POB CN710, Princeton, NJ 08544 USA. RI Gnanadesikan, Anand/A-2397-2008 OI Gnanadesikan, Anand/0000-0001-5784-1116 NR 45 TC 54 Z9 55 U1 2 U2 7 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 1999 VL 13 IS 1 BP 199 EP 220 DI 10.1029/1998GB900013 PG 22 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 173WP UT WOS:000079003000015 ER PT J AU Brady, M Dima, A Gebase, L Kass, M Montanez-Rivera, C Rosenthal, L AF Brady, M Dima, A Gebase, L Kass, M Montanez-Rivera, C Rosenthal, L TI VRML testing: Making VRML worlds look the same everywhere SO IEEE COMPUTER GRAPHICS AND APPLICATIONS LA English DT Article C1 Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Brady, M (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. NR 7 TC 1 Z9 1 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0272-1716 J9 IEEE COMPUT GRAPH JI IEEE Comput. Graph. Appl. PD MAR-APR PY 1999 VL 19 IS 2 BP 59 EP 67 DI 10.1109/38.749124 PG 9 WC Computer Science, Software Engineering SC Computer Science GA 169EF UT WOS:000078734000010 ER PT J AU Bradshaw, JM Greaves, M Holmback, H Karygiannis, T Jansen, W Silverman, BG Suri, N Wong, A AF Bradshaw, JM Greaves, M Holmback, H Karygiannis, T Jansen, W Silverman, BG Suri, N Wong, A TI Agents for the masses? SO IEEE INTELLIGENT SYSTEMS & THEIR APPLICATIONS LA English DT Article C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Penn, Philadelphia, PA 19104 USA. Univ W Florida, Inst Human & Machine Cognit, Pensacola, FL 32514 USA. Sun Microsyst Inc, Mt View, CA 94043 USA. NR 29 TC 12 Z9 12 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1094-7167 J9 IEEE INTELL SYST APP JI IEEE Intell. Syst. Appl. PD MAR-APR PY 1999 VL 14 IS 2 BP 53 EP 63 DI 10.1109/5254.757632 PG 11 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 183JU UT WOS:000079551100018 ER PT J AU Marks, R AF Marks, R TI The IEEE802. 16 working group on broadband wireless SO IEEE NETWORK LA English DT Editorial Material AB This installment of "IEEE 802 Perspectives" describes the new initiative on Broadband Wireless Access that has formed Working Group 802.16 in the IEEE 802 LAN/MAN Standards Committee. The author of this month's column, Roger B. Marks, is responsible for the formation of this Working Group and is the chair. This effort is supported by both the IEEE Computer Society and the IEEE Microwave Theory and Techniques Society. These perspectives, which will appear in each issue of IEEE Network, are aimed to provide the reader with highlights of IEEE 802 activities in order to enable better dissemination of these standards into marketable products as well as seek new ideas to be brought into the IEEE 802 arena. I hope that readers find dib column useful and look forward to providing future issues on IEEE 802. Please send suggestions, criticisms, and requests for future articles to jcarlo@ti.com, IEEE 802 chair. C1 Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Marks, R (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80309 USA. NR 0 TC 12 Z9 12 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 0890-8044 J9 IEEE NETWORK JI IEEE Netw. PD MAR-APR PY 1999 VL 13 IS 2 BP 4 EP 5 DI 10.1109/65.768483 PG 2 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 183HF UT WOS:000079547600002 ER PT J AU Morris, RW AF Morris, RW TI Adaptive learning systems: Building an educational infrastructure SO IEEE TECHNOLOGY AND SOCIETY MAGAZINE LA English DT Article C1 Natl Inst Stand & Technol, Adv Technol Program, Gaithersburg, MD 20899 USA. RP Morris, RW (reprint author), Natl Inst Stand & Technol, Adv Technol Program, A430 Adm Bldg, Gaithersburg, MD 20899 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0278-0097 J9 IEEE TECHNOL SOC MAG JI IEEE Technol. Soc. Mag. PD SPR PY 1999 VL 18 IS 1 BP 43 EP 45 DI 10.1109/44.752244 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 176BX UT WOS:000079131600009 ER PT J AU Rozenberg, AD Ritter, MJ Melville, WK Gottschall, CC Smirnov, AV AF Rozenberg, AD Ritter, MJ Melville, WK Gottschall, CC Smirnov, AV TI Free and bound capillary waves as microwave scatterers: Laboratory studies SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE Bragg scattering; electromagnetic scattering from tough surfaces; remote sensing ID GRAVITY-WAVES; SURFACE-WAVES; GRAZING-INCIDENCE; WIND; RADAR AB Laboratory measurements of the fine space-time structure of short gravity-capillary waves, as well as lice-band scattering at grazing and moderate incidence fr om wind waves in the large Delft Hydraulics Laboratory wind-wave channel are presented, This study was stimulated by the need to verify the processes that significantly contribute to scattering at grazing and moderate incidence, A scanning laser slope gauge was used for measuring capillary waves from 2-mm to 2-cm wavelengths and frequencies ranging up to 100 Hz, A dual-polarized (vertical, VV, and horizontal, HH), coherent, pulsed Ku-band scatterometer with good temporal resolution (3 ns) was used to obtain simultaneous Doppler spectra and the absolute cross section of scattered signals for grazing angles 6 and 25 degrees and for winds in the range 2.5-12.5 m/s, Two-dimensional (2-D) filtering and bispectral analyses were used to separate and study the influence of free and bound surface waves. The results of this study demonstrate that the frequency-wavenumber spectra of capillary waves consist of two parts, The first corresponds to free capillary waves, which satisfy the dispersion relationship, The second corresponds to bound parasitic capillary waves, which are located near the crests of steep wind waves. The phase velocity of these capillary waves is approximately equal to the phase velocity of the steep waves. Measurements of the Doppler frequency of the scattered signals show that the Doppler spectra also have a bimodal structure, While the first low-frequency part of the spectrum corresponds to the Bragg scattering from the free capillary waves, the high-frequency part is associated with Bragg scattering from the bound capillary waves on the crests of the steep waves. This type of scattering is predominant for the upwind direction of illumination (especially for HH-polarization). C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Rozenberg, AD (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NR 22 TC 14 Z9 16 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 1999 VL 37 IS 2 BP 1052 EP 1065 DI 10.1109/36.752223 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 177VL UT WOS:000079231700017 ER PT J AU Silva, TJ Crawford, TM AF Silva, TJ Crawford, TM TI Methods for determination of response times of magnetic head materials SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 9th Annual Magnetic Recording Conference on Magnetic Recording Heads (TMRC 98) CY AUG 17-19, 1998 CL BOULDER, COLORADO DE coplanar waveguide; inductive voltage; Landau-Lifshitz damping; magnetic switching speed; magneto-optic sampling; second-harmonic magneto-optic Kerr effect ID GENERATION AB Measurements of magnetization response times in thin-film Permalloy are made by both electrical and optical methods. The electrical method measures the inductive voltage generated in a waveguide by the changing magnetization, The optical technique uses standard pump-probe sampling methods combined with the second-harmonic magneto-optic Kerr effect to, directly measure magnetization angle as a function of time. Results of these measurements for a 75 nm thick Permalloy film are in good qualitative agreement. C1 Natl Inst Stand & Technol, Boulder, CO USA. RP Silva, TJ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 15 TC 20 Z9 20 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAR PY 1999 VL 35 IS 2 BP 671 EP 676 DI 10.1109/20.750626 PN 1 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 174EW UT WOS:000079022000012 ER PT J AU Levine, J AF Levine, J TI Time transfer using multi-channel GPS receivers SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB This report is on time transfer experiments using a Global Positioning System (GPS) receiver constructed using a commercial GPS "engine" and a standard PC. The receiver measures the time difference between the local clock and al pps signal synchronized to GPS time using data from up to 8 satellites. The receiver also reports the difference between GPS time as estimated using each of the satellites being tracked and the composite output pulses that have a rate of I Hz (1 pps signal). These data can be used to construct the standard Ig-minute tracks as defined in the BIPM standard; the same data also can be averaged in other ways that make better use of the multi-channel capabilities of the hardware. The 13-minute averages can be directly compared with standard time-transfer receivers using common-view analysis. The results of the tests suggest that the methods currently used for national and international time and frequency coordination should be re-examined, and an alternative approach based on multi-channel receivers is suggested that should be more flexible, simpler, and easier to operate than the current system. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. EM jlevine@boulder.nist.gov NR 5 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0885-3010 EI 1525-8955 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAR PY 1999 VL 46 IS 2 BP 392 EP 398 DI 10.1109/58.753028 PG 7 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 177VG UT WOS:000079231300013 PM 18238436 ER PT J AU Froyd, KD Lovejoy, ER AF Froyd, KD Lovejoy, ER TI Direct measurement of the C2H5C(O)O-2+NO reaction rate coefficient using chemical ionization mass spectrometry SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article ID PEROXYACETYL NITRATE PAN; PEROXYPROPIONYL NITRATE; CH3C(O)O-2+NO REACTION; ATMOSPHERIC CHEMISTRY; EQUATORIAL PACIFIC; RADICAL REACTIONS; KINETICS; NO; TROPOSPHERE; PHOTOLYSIS AB The rate coefficient for the reaction of the peroxypropionyl radical (C2H5C(O)O-2) with NO was measured with a laminar flow reactor over the temperature range 226-406 K. The C2H5C(O)O-2 reactant was monitored with chemical ionization mass spectrometry. The measured rate coefficients are k(T) = (6.7 +/- 1.7) x 10(-12) exp{(340 + 80)/T) cm(3) molecule(-1) s(-1) and k(298 K) = (2.1 +/- 0.2) x 10(-11) cm(3) molecule(-1) s(-1). Our results are comparable to recommended rate coefficients for the analogous CH3C(O)O-2 + NO reaction. Heterogeneous effects, pressure dependence, and concentration gradients inside the flow reactor are examined. (C) 1999 John Wiley & Sons, Inc. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Lovejoy, ER (reprint author), NOAA, Aeron Lab, 325 Broadway,R-E-AL2, Boulder, CO 80303 USA. RI Froyd, Karl/H-6607-2013 NR 43 TC 8 Z9 8 U1 1 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD MAR PY 1999 VL 31 IS 3 BP 221 EP 228 DI 10.1002/(SICI)1097-4601(1999)31:3<221::AID-KIN4>3.0.CO;2-2 PG 8 WC Chemistry, Physical SC Chemistry GA 169WH UT WOS:000078771800004 ER PT J AU Laesecke, A Luddecke, TOD Hafer, RF Morris, DJ AF Laesecke, A Luddecke, TOD Hafer, RF Morris, DJ TI Viscosity measurements of ammonia, R32, and R134a, vapor buoyancy and radial acceleration in capillary viscometers SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE ammonia; alternative refrigerants; capillary viscometer; R32; R134a; saturated liquid; radial acceleration correction; vapor buoyancy; viscosity ID SATURATED LIQUID-PHASE; REFRIGERANTS; PRESSURES; MIXTURES; DIFLUOROMETHANE; TEMPERATURES; HFC-134A; TOLUENE AB The saturated liquid viscosity of ammonia (NH3) and of the hydrofluorocarbons, difluoromethane (CH2F2, R32) and 1,1,1,2-tetrafluoroethane (CF3-CH2F, R134a), was measured in a sealed gravitational viscometer with a straight vertical capillary. The combined temperature range was from 250 to 350 K. The estimated uncertainty of the ammonia measurements is +/-3.3 and +/-2 to 2.4% for the hydrofluorocarbons with a coverage factor of two. The results are com pared with literature data which have been measured with capillary viscometers of different design. Agreement within the combined experimental uncertainty is achieved when some of the literature data sets are corrected for the vapor buoyancy effect and when a revised radial acceleration correction is applied to data which were obtained in viscometers with coiled capillaries. An improved correction for the radial acceleration is proposed. It is necessary to extend international viscometry standards to sealed gravitational capillary instruments because the apparent inconsistencies between refrigerant viscosity data from different laboratories cannot be explained by contaminated samples. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Hannover, Inst Thermodynam, D-30167 Hannover, Germany. RP Laesecke, A (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 50 TC 27 Z9 30 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAR PY 1999 VL 20 IS 2 BP 401 EP 434 DI 10.1023/A:1022644718603 PG 34 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 212WK UT WOS:000081240500003 ER PT J AU Hurly, JJ AF Hurly, JJ TI Thermophysical properties of gaseous CF4 and C2F6 from speed-of-sound measurements SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE CF4; C2F6; equation of state; hexafluoroethane; speed of sound; tetrafluoromethane; thermodynamic properties; virial coefficients ID VIRIAL-COEFFICIENTS; THERMODYNAMIC PROPERTIES; ACOUSTIC MEASUREMENTS; REFRIGERANTS; MIXTURES; SYSTEM AB A cylindrical resonator was employed to measure the sound speeds in gaseous CF4 and C2F6. The CF4 measurements span the temperature range 300 to 475 K, while the C2F6 measurements range From 210 to 475 K. For both gases, the pressure range was 0.1 MPa to the lesser of 1.5 MPa or 80% of the sample's vapor pressure. Typically, the speeds of sound have a relative uncertainty of less than 0.01% and the ideal-gas heat capacities derived from them have a relative uncertainty of less than 0.1%. The heat capacities agree with those determined from spectroscopic data. The sound speeds were fitted with the virial equation of state to obtain the temperature-dependent density virial coefficients. Two models for the virial coefficients were employed, one based on square-well potentials and the second based on a Kihara spherical-core potential. The resulting virial equations reproduce the sound-speed measurements to within 0.005% and yield densities with relative uncertainties of 0.1% or less. The viscosity calculated from the Kihara potential is 2 to 11% less than the measured viscosity. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Hurly, JJ (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 44 TC 20 Z9 20 U1 0 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAR PY 1999 VL 20 IS 2 BP 455 EP 484 PG 30 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 212WK UT WOS:000081240500006 ER PT J AU Higashi, Y AF Higashi, Y TI Vapor-liquid equilibria for the binary difluoromethane (R-32) plus propane (R-290) mixture SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE alternative refrigerants; azeotropic mixture; Helmholtz free energy mixture model; R-32+R-290 mixture; REFPROP 6.0; vapor-liquid equilibria ID COEXISTENCE CURVE; CRITICAL LOCUS AB The vapor-liquid equilibrium of the mixture composed of difluoromethane (R-32) and propane (R-290) was studied in the temperature range between 273.15 and 313.15 K. The experimental uncertainties of temperature, pressure, and composition measurements were estimated to be within +/-10 mK, +/-3 kPa, and +/-0.4 mol %, respectively. Comparisons between the present data and available experimental data were made using the Helmholtz free energy mixture model (HMM) adopted in the thermophysical properties program package, REFPROP 6.0, as a baseline. In addition, the existence of an azeotrope and the determination of new adjustable parameters for HMM for the R-32 + R-290 mixture are discussed. C1 Iwaki Meisei Univ, Dept Mech Engn, Iwaki, Fukushima 9708551, Japan. RP Higashi, Y (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 6 TC 12 Z9 12 U1 1 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAR PY 1999 VL 20 IS 2 BP 507 EP 518 DI 10.1023/A:1022653020420 PG 12 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 212WK UT WOS:000081240500008 ER PT J AU Kiselev, SB Abdulagatov, IM Harvey, AH AF Kiselev, SB Abdulagatov, IM Harvey, AH TI Equation of state and thermodynamic properties of pure D2O and D2O+H2O mixtures in and beyond the critical region SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE binary mixtures; critical region; D2O; equation of state H2O; phase behavior; thermodynamic properties ID NONASYMPTOTIC CRITICAL-BEHAVIOR; EXTENDED CRITICAL REGION; BINARY-MIXTURES; FLUID MIXTURES; CORRESPONDING STATES; CROSSOVER FUNCTIONS; SINGLE-COMPONENT; PHASE-BEHAVIOR; CRITICAL-POINT; FIELD-THEORY AB A parametric crossover model is adapted to represent the thermodynamic properties of pure D2O in the extended critical region. The crossover equation of state for D2O incorporates scaling laws asymptotically close to the critical point and is transformed into a regular classical expansion far From the critical point. An isomorphic generalization of the law of corresponding states is applied to the prediction of thermodynamic properties and the phase behavior of D2O + H2O mixtures over a wide region around the locus of vapor-liquid critical points. A comparison is made with experimental data for pure D2O and for the D2O + H2O mixture. The equation of slate yields a good representation of thermodynamic property data in the range of temperatures 0.8T(c)(x) less than or equal to T less than or equal to 1.5T(c)(x) and densities 0.35 rho(c)(x) less than or equal to rho less than or equal to 1.65 rho(c)(x). C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Russian Acad Sci, Dagestan Sci Ctr, Inst Geothermal Problems, Makhachkala 367030, Dagestan, Russia. RP Kiselev, SB (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 56 TC 20 Z9 20 U1 1 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD MAR PY 1999 VL 20 IS 2 BP 563 EP 588 DI 10.1023/A:1022609205399 PG 26 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 212WK UT WOS:000081240500011 ER PT J AU Tassey, G Doremus, P AF Tassey, G Doremus, P TI A permanent research credit SO ISSUES IN SCIENCE AND TECHNOLOGY LA English DT Editorial Material C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Tassey, G (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 2 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0748-5492 J9 ISSUES SCI TECHNOL JI Issues Sci. Technol. PD SPR PY 1999 VL 15 IS 3 BP 14 EP + PG 2 WC Engineering, Multidisciplinary; Engineering, Industrial; Multidisciplinary Sciences; Social Issues SC Engineering; Science & Technology - Other Topics; Social Issues GA 185EN UT WOS:000079655300013 ER PT J AU Sharpless, KE Gill, LM Margolis, SA Wise, SA Elkins, E AF Sharpless, KE Gill, LM Margolis, SA Wise, SA Elkins, E TI Preparation of Standard Reference Material 2383 (Baby Food Composite) and use of an interlaboratory comparison exercise for value assignment of its nutrient concentrations SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article AB The preparation of the recently released Standard Reference Material (SRM) 2383 Baby Food Composite and the process used for value assignment of nutrient concentrations are reported. SRM 2383 can be used as a control material when assigning values to in-house control materials and when validating analytical methods for measuring proximates, vitamins, and minerals in baby food and similar matrixes. The SRM was prepared as a commercial baby food would be prepared, with the same ingredients. The Certificate of Analysis for SRM 2383 provides assigned values for concentrations of proximates, vitamins, and minerals for which product labeling is required by the Nutrition Labeling and Education Act of 1990. These assigned values were based on measurements by the National institute of Standards: and Technology (NIST) and/or collaborating laboratories. Assignment of analyte concentrations based solely on analyses by collaborating laboratories is described in this paper. Certified values are provided for retinol, tocopherols, and several carotenoids including total beta-carotene the certification of and methodology used for measurement of these analytes is discussed in a companion paper (this issue, page 288). Reference values are provided for solids, ash, fat, nitrogen, protein, carbohydrate, calories, vitamin B-1, vitamin B-2, vitamin B-6, niacin, biotin, calcium, phosphorus, magnesium, manganese, iron, zinc, copper sodium, potassium, and chloride. Reference values for addi tional carotenoids are reported in the companion paper (this issue, page 288). Information values are provided for iodine, selenium, molybdenum, vitamin D, vitamin B-12, folic acid, pantothenic acid, choline, inositol, sugars, total dietary fiber and 3 classes of fats. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Food Processors Assoc, Washington, DC 20005 USA. RP Sharpless, KE (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Stop 8392, Gaithersburg, MD 20899 USA. NR 12 TC 14 Z9 14 U1 0 U2 5 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 1999 VL 82 IS 2 BP 276 EP 287 PG 12 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA 179PT UT WOS:000079338400011 PM 10191534 ER PT J AU Sharpless, KE Arce-Osuna, M Thomas, JB Gill, LM AF Sharpless, KE Arce-Osuna, M Thomas, JB Gill, LM TI Value assignment of retinol, retinyl palmitate, tocopherol, and carotenoid concentrations in Standard Reference Material 2383 (Baby Food Composite) SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article ID HUMAN SERUM; CERTIFICATION; SEPARATION AB In 1997, the National institute of Standards and Technology (NIST) released Standard Reference Material (SRM) 2383 Baby Food Composite, This SRM can be used as a control material when assigning values to in-house control materials and when validating analytical methods for the measurement of proximates, vitamins, minerals, and trace elements in baby foods and similar matrixes. The Certificate of Analysis for SRM 2383 provides certified and reference values for concentrations of lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, delta-tocopherol, gamma-tocopherol, alpha-tocopherol, retinol, and retinyl palmitate for 2 types of sample preparation-extraction and saponification, The assigned values were based on the agreement of measurements made by NIST and collaborating laboratories. The Certificate of Analysis also provides reference and information values for concentrations of proximates, minerals, and additional vitamins; assignment of these values is discussed in a companion paper (this issue, page 276). 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 19 TC 31 Z9 31 U1 0 U2 2 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 1999 VL 82 IS 2 BP 288 EP 296 PG 9 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA 179PT UT WOS:000079338400012 PM 10191535 ER PT J AU Tokay, A Short, DA Williams, CR Ecklund, WL Gage, KS AF Tokay, A Short, DA Williams, CR Ecklund, WL Gage, KS TI Tropical rainfall associated with convective and stratiform clouds: Intercomparison of disdrometer and profiler measurements SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RAINDROP SIZE DISTRIBUTIONS; WIND PROFILERS; SYSTEMS; CLASSIFICATION; PRECIPITATION; SATELLITE; RETRIEVAL; CLUSTERS; MONSOON; RADAR AB The motivation for this research is to move in the direction of improved algorithms for the remote sensing of rainfall, which are crucial for meso- and large-scale circulation studies and climate applications through better determinations of precipitation type and latent heating profiles. Toward this end a comparison between two independent techniques, designed to classify precipitation type from 1) a disdrometer and 2) a 915-MHz wind profiler. is presented, based on simultaneous measurements collected at the same site during the Intensive Observing Period of the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment. Disdrometer-derived quantities such as differences in drop size distribution parameters, particularly the intercept parameter N-0 and rainfall rate, were used to classify rainfall as stratiform or convective. At the same lime. profiler-derived quantities, namely, Doppler velocity, equivalent reflectivity, and spectral width, from Doppler spectra were used to classify precipitation type in four categories: shallow convective, deep convective, mixed convective-stratiform. and stratiform, Overall agreement between the two algorithms is Found to be reasonable, Given the disdrometer stratiform classification, the mean profile of reflectivity shows a distinct bright band and associated large vertical gradient in Doppler velocity, both indicators of stratiform rain. I;or the disdrometer convective classification the mean profile of reflectivity lacks a bright band, while the vertical gradient in Doppler velocity below the melting level is opposite to the stratiform case. Given the profiler classifications, in the order shallow-deep-mixed-stratiform, the composite raindrop spectra for a rainfall rate of 5 mm h(-1) show an increase in D-o, the median volume diameter, consistent with the dominant microphysical processes responsible for drop formation. Nevertheless, the intercomparison does reveal some limitations in the classification methodology utilizing the disdrometer or profiler algorithms in isolation. In particular, 1) the disdrometer stratiform classification includes individual cases in which the vertical profiles appear convective, but these usually occur at times when the disdrometer classification is highly variable; 2) the profiler classification scheme also appears to classify precipitation too frequently as stratiform by including cases that have small vertical Doppler velocity gradients at the melting level but no bright band; and 3) the profiler classification scheme includes a category of mixed (stratiform-convective) precipitation that has some features in common with deep convection (e.g., enhanced spectral width above the melting level) but other features in common with stratiform precipitation (e.g., well-developed melting layer signature). Comparison of the profiler-derived vertical structure with disdrometer-determined rain rater reveals that almost all cases of rain rates greater than 10 mm h(-1) are convective. For rain rates less than 5 mm h(-1) all four profiler-determined precipitation classes are well represented. C1 NASA, Goddard Space Flight Ctr, Trop Rainfall Measuring Mission Off, Greenbelt, MD 20771 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Tokay, A (reprint author), NASA, Goddard Space Flight Ctr, Trop Rainfall Measuring Mission Off, Code 910-1, Greenbelt, MD 20771 USA. RI Williams, Christopher/A-2723-2015 OI Williams, Christopher/0000-0001-9394-8850 NR 30 TC 73 Z9 73 U1 1 U2 3 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 1999 VL 38 IS 3 BP 302 EP 320 DI 10.1175/1520-0450(1999)038<0302:TRAWCA>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 179GX UT WOS:000079319100006 ER PT J AU Balchin, GA Amirtharaj, PM Silvestre, C Thompson, P AF Balchin, GA Amirtharaj, PM Silvestre, C Thompson, P TI Photoluminescence quenching in Si1-xGex/Si multiple quantum wells grown with atomic hydrogen SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MOLECULAR-BEAM EPITAXY; SILICON; SI; GE; HETEROSTRUCTURES; SUPERLATTICES AB We compare the photoluminescence spectra from a series of Si1-xGex/Si (0.1 less than or equal to x less than or equal to 0.3) multiple quantum well (MQW) samples grown with atomic hydrogen to a series of similar samples grown without atomic hydrogen. All of the samples were grown at 710 degrees C. We observe intense quantum confined photoluminescence in the Si1-xGex/Si MQW samples grown without atomic hydrogen. No quantum confined photoluminescence was observed in the Si1-xGex/Si MQW samples grown with atomic hydrogen. This was unexpected, since quantum confined photoluminescence has been observed in the hydrogen-assisted growth of Si1-xGex/Si quantum well structures grown at lower temperatures by other researchers. We believe that this is caused by defects, introduced into the samples during growth with atomic hydrogen, which lead to efficient nonradiative centers that compete with the radiative centers. These defects lead to a reduction of the photoluminescence of the samples grown with atomic hydrogen. Since hydrogen is used as a surfactant to reduce the deleterious effects due to Ge segregation, understanding its role is an important step in SiGe materials development. [S0021-8979(99)06505-6]. C1 NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. USN, Res Lab, Washington, DC 20375 USA. RP USN, Ctr Surface Warfare, Dahlgren Div, Dahlgren, VA 22448 USA. EM gbalchi@nswc.navy.mil NR 34 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 1999 VL 85 IS 5 BP 2875 EP 2880 DI 10.1063/1.369632 PG 6 WC Physics, Applied SC Physics GA 169YH UT WOS:000078777000062 ER PT J AU Ecklund, WL Williams, CR Johnston, PE Gage, KS AF Ecklund, WL Williams, CR Johnston, PE Gage, KS TI A 3-GHz profiler for precipitating cloud studies SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID WIND PROFILER; RADAR REFLECTIVITY; SYSTEMS; AIR; CUMULUS; ECHOES AB A 3-GHz profiler has been developed by the National Oceanic and Atmospheric Administration's Aeronomy Laboratory to observe the evolution and vertical structure of precipitating cloud systems. The profiler is very portable, robust, and relatively inexpensive, so that continuous, unattended observations of overhead precipitation can be obtained, even at remote locations. The new profiler is a vertically looking Doppler radar that operates at S band, a commonly used band for scanning weather radars (e.g., WSR-88D). The profiler has many features in common with the 915-MHz profiler developed at the Aeronomy Laboratory during the past decade primarily for measurement of lower-tropospheric winds in the Tropics. This paper presents a description of the new profiler and evaluates it in the field in Illinois and Australia in comparison with UHF lower-tropospheric profilers. In Illinois, the new profiler was evaluated alongside a collocated 915-MHz profiler at the Flatland Atmospheric Observatory. In Australia it Was evaluated alongside a 920-MHz profiler during the Maritime Continent Thunderstorm Experiment. The results from these campaigns confirm the approximate 20-dB improvement in sensitivity, as expected for Rayleigh scatter. The results show that the new profiler provides a substantial improvement in the ability to observe deep cloud systems in comparison with the 915-MHz profilers. C1 NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Ecklund, WL (reprint author), NOAA, ERL, Aeron Lab, 325 Broadway R-E-AL3, Boulder, CO 80303 USA. RI Williams, Christopher/A-2723-2015; Johnston, Paul/E-1914-2016 OI Williams, Christopher/0000-0001-9394-8850; Johnston, Paul/0000-0002-4046-9351 NR 39 TC 36 Z9 36 U1 0 U2 1 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 1999 VL 16 IS 3 BP 309 EP 322 DI 10.1175/1520-0426(1999)016<0309:AGPFPC>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 176GG UT WOS:000079142600001 ER PT J AU Smith, WL Feltz, WE Knuteson, RO Revercomb, HE Woolf, HM Howell, HB AF Smith, WL Feltz, WE Knuteson, RO Revercomb, HE Woolf, HM Howell, HB TI The retrieval of planetary boundary layer structure using ground-based infrared spectral radiance measurements SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID RAMAN LIDAR; WATER-VAPOR AB The surface-based Atmospheric Emitted Radiance Interferometer (AERI) is an important measurement component of the Department of Energy Atmospheric Radiation Measurement Program. The method used to retrieve temperature and moisture profiles of the plantetary boundary layer from the AERI's downwelling spectral radiance observations is described. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. Univ Wisconsin, NOAA, Natl Environm Satellite & Data Informat Serv, Madison, WI 53706 USA. RP Smith, WL (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, MS-401, Hampton, VA 23681 USA. EM bill.l.smith@larc.nasa.gov NR 22 TC 67 Z9 71 U1 1 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 1999 VL 16 IS 3 BP 323 EP 333 DI 10.1175/1520-0426(1999)016<0323:TROPBL>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 176GG UT WOS:000079142600002 ER PT J AU Skipor, AK Jacobs, JJ Yu, L Black, J AF Skipor, AK Jacobs, JJ Yu, L Black, J TI Comparison of zeeman background corrected atomic absorption spectrometric and inductively coupled plasma mass spectrometric detection of trace elements in electrothermally vaporized serum SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE titanium; aluminum; vanadium; Zeeman background corrected atomic absorption spectrometry; electrothermal vaporization inductively coupled plasma mass spectrometry ID TITANIUM AB There is continued interest in the measurement of degradation products of metallic implants in biological tissues and fluids, A study was conducted to compare analytical results obtained by the Zeeman Background Corrected Atomic Absorption Spectrometric and Inductively Coupled Plasma Mass Spectrometric techniques on a uniform set of triple-element (Ti, Al, and V) spiked human serum specimens over concentration ranges up to 20 ppb (20 ng/ml), The results indicate that the two methods are comparable, The positive and negative aspects of each method of instrumental analysis are discussed. (C) 1999 John Wiley & Sons, Inc. C1 Rush Presbyterian St Lukes Med Ctr, Dept Orthopaed Surg, Chicago, IL 60612 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. IMN Biomat, King Of Prussia, PA USA. RP Skipor, AK (reprint author), Rush Presbyterian St Lukes Med Ctr, Dept Orthopaed Surg, 1653 W Congress Pkwy, Chicago, IL 60612 USA. RI Yu, Lee/N-7263-2015; OI Yu, Lee/0000-0002-8043-6853; Jacobs, Joshua/0000-0003-3902-7334 FU NIAMS NIH HHS [AR39310] NR 8 TC 2 Z9 3 U1 0 U2 0 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 SPR PY 1999 VL 48 IS 1 BP 90 EP 93 DI 10.1002/(SICI)1097-4636(1999)48:1<90::AID-JBM15>3.0.CO;2-A PG 4 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 164YC UT WOS:000078490300015 PM 10029155 ER PT J AU Archer, DG Kematick, RJ Myers, CE Agarwal, S Cotts, EJ AF Archer, DG Kematick, RJ Myers, CE Agarwal, S Cotts, EJ TI Enthalpy increment measurements from 4.5 K to 350 K and the thermodynamic properties of the titanium silicide TiSi(cr) SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article AB Enthalpy increments for TiSi(cr) were measured from 4.5 K to 350 K with an adiabatic calorimeter. A small anomaly, of unknown origin, was detected between 5 K and 15 K. From the present measurements and other measurements in the literature, the enthalpy relative to 0 K, the entropy, and the heat capacity of TiSi(cr) to 1500 K were calculated. The coefficient for the heat capacity of the conduction electrons, gamma(el), was estimated from the measurements. Thermodynamic properties for formation from the elements at 298.15 K were also given. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. SUNY Binghamton, Dept Chem, Binghamton, NY 13902 USA. SUNY Binghamton, Dept Phys, Binghamton, NY 13902 USA. RP Archer, DG (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 13 TC 4 Z9 4 U1 0 U2 1 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 1999 VL 44 IS 2 BP 167 EP 172 DI 10.1021/je9802120 PG 6 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 177RQ UT WOS:000079225200001 ER PT J AU Higashi, Y AF Higashi, Y TI Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane plus 1,1,1,2-tetrafluoroethane (R125/R134a) SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID MIXTURES AB The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1,2-tetrafluoroethane (R134a) was measured along four isotherms between 283 K and 313 K. The vapor-liquid coexistence curve at constant composition near the mixture critical point was measured by the observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.2670 and 0.6648 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R134a mixture is correlated as a function of composition. C1 Iwaki Meisei Univ, Dept Mech Engn, Iwaki, Fukushima 9708551, Japan. RP Higashi, Y (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, 325 Broadway, Boulder, CO 80303 USA. NR 10 TC 7 Z9 8 U1 1 U2 1 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 1999 VL 44 IS 2 BP 328 EP 332 DI 10.1021/je980265h PG 5 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 177RQ UT WOS:000079225200033 ER PT J AU Higashi, Y AF Higashi, Y TI Vapor-liquid equilibrium, coexistence curve, and critical locus for pentafluoroethane plus 1,1,1-trifluoroethane (R125/R143a) SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID CRITICAL PARAMETERS; MIXTURES AB The vapor-liquid equilibrium for pentafluoroethane (R125) + 1,1,1-trifluoroethane (R143a) was measured by the static method in the temperature range between 273.15 K and 313.15 K. The vapor-liquid coexistence curve near the critical point was measured by observation of the meniscus disappearance. The critical temperatures and critical densities of the 0.4118 and 0.6208 mole fraction of R125 were determined from the saturation densities along the coexistence curve in the critical region. In addition, the critical locus for the R125/R143a mixture is correlated as a function of composition. C1 Iwaki Meisei Univ, Dept Mech Engn, Iwaki, Fukushima 9708551, Japan. RP Higashi, Y (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, 325 Broadway, Boulder, CO 80303 USA. NR 13 TC 11 Z9 14 U1 0 U2 1 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 1999 VL 44 IS 2 BP 333 EP 337 DI 10.1021/je980266+ PG 5 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 177RQ UT WOS:000079225200034 ER PT J AU Heller, SR AF Heller, SR TI OmniPage Pro 9.0 for Windows SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), 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 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD MAR-APR PY 1999 VL 39 IS 2 BP 421 EP 421 DI 10.1021/ci980268y PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 181TH UT WOS:000079458100037 ER PT J AU Gordon, MS Schmidt, MW Chaban, GM Glaesemann, KR Stevens, WJ Gonzalez, C AF Gordon, MS Schmidt, MW Chaban, GM Glaesemann, KR Stevens, WJ Gonzalez, C TI A natural orbital diagnostic for multiconfigurational character in correlated wave functions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 2ND-ORDER PERTURBATION-THEORY; ONE-ELECTRON PROPERTIES; COUPLED-CLUSTER THEORY; LEVEL SHIFT; BASIS SETS; OPEN-SHELL; SPECTROSCOPY; MOLECULES; ENERGY AB The natural orbitals and their corresponding occupation numbers are constructed for several interesting problems to demonstrate that the existence of negative natural orbital occupation numbers for single reference correlation methods provides a simple diagnostic for the need for a multiconfigurational description of the wave function. (C) 1999 American Institute of Physics. [S0021-9606(99)30209-9]. C1 Iowa State Univ, Dept Chem, Ames, IA 50011 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gordon, MS (reprint author), Iowa State Univ, Dept Chem, Ames, IA 50011 USA. RI Glaesemann, Kurt/B-4841-2010; OI Glaesemann, Kurt/0000-0002-9512-1395 NR 46 TC 73 Z9 73 U1 2 U2 12 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAR 1 PY 1999 VL 110 IS 9 BP 4199 EP 4207 DI 10.1063/1.478301 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 168HP UT WOS:000078686400011 ER PT J AU O'Hare, PAG Tomaszkiewicz, I Beck, CM Seifert, HJ AF O'Hare, PAG Tomaszkiewicz, I Beck, CM Seifert, HJ TI Thermodynamics of silicon nitride. I. Standard molar enthalpies of formation Delta H-f(m)0 at the temperature 298.15 K of alpha-Si3N4 and beta-Si3N4a SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE silicon nitride; calorimetry; fluorine combustion; enthalpy of formation; enthalpy of transition ID COMBUSTION CALORIMETRY; FLUORINE; THERMOCHEMISTRY; SILICIDES; ENERGY; DISILICIDE; SYSTEM; SULFUR AB Flourine bomb calorimetric measurements of the massic energy of the reaction: Si3N4(cr,alpha- or beta-) + 6F(2)(g) = 3SiF(4)(g) + 2N(2)(g) have shown that, within the combined uncertainties of the experiments, there is a negligible enthalpy difference between the alpha- and beta-forms of Si3N4 at the temperature 298.15 K. The standard molar enthalpies of formation at T = 298.15 K have been determined: Delta(f)H(m)(o),(alpha-Si3N4) = -(828.9 +/- 3.4) kJ mol(-1), Delta(f)H(m)(o)(beta-Si3N4)=(827.8 +/- 2.5) KJ.mol(-1). These results are approximately 40 kJ.mol(-1) more negative than the recommended value given in the most recent authoritative compilations of chemical thermodynamic information for inorganic substances. The enthalpy difference between the alpha- and beta-forms, (1 +/- 4) kJ.mol(-1) at T = 298.15 K, is too small to be measured reliably by combustion calorimetry, but it supports an earlier estimate of 1.25 kJ.mol(-1) from a modeling study. (C) 1999 Academic Press. C1 NIST, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Polish Acad Sci, Inst Phys Chem, Warsaw, Poland. NIST, Analyt Chem Res Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Max Planck Inst Met Forsch, Pulvermet Lab, D-70569 Stuttgart, Germany. RP O'Hare, PAG (reprint author), NIST, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. EM patrick.ohare@nist.gov NR 53 TC 15 Z9 15 U1 1 U2 5 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 MAR PY 1999 VL 31 IS 3 BP 303 EP 322 DI 10.1006/jcht.1998.0454 PG 20 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 179PA UT WOS:000079336200001 ER PT J AU Chirico, RD Knipmeyer, SE Steele, WV AF Chirico, RD Knipmeyer, SE Steele, WV TI Thermodynamic properties of the methylpyridines. Part 1. Heat capacity measurements for 4-methylpyridine between T = 6.4 K and T = 18.6 K, resolution of low-temperature contributions, and reconciliation of calorimetrically and spectroscopically derived standard entropies SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE heat capacity; methyl group rotational barrier; entropy ID XYLENE ISOMERIZATION; RECOMMENDED VALUES; NITROGEN-COMPOUNDS; ISOQUINOLINE; EQUILIBRIA; QUINOLINE; PYRIDINE AB Heat capacities and enthalpy increments between the temperatures 6.4 K and 320 K were determined for 4-methylpyridine (Chemical Abstract registry number 108-89-4) by adiabatic calorimetry. Results for temperatures greater than or equal to 20 K were found to be in excellent accord with literature values; however, accord for < 20 K was poor. The new experimental heat capacities for temperatures <20 K are used with results of inelastic neutron scattering (i.n.s.) studies from the literature to resolve the contributions to the heat capacities. Contributions arising from rotation of the methyl group are discussed in detail. Results are interpreted in terms of a three-fold barrier to rotation in accord with recent i.n.s. studies. Earlier suggestions in the literature of a six-fold potential are not supported. Revised thermodynamic functions for the condensed phases of 4-methylpyridine are derived. Revised thermodynamic functions are corroborated through accord between calorimetric and statistically derived standard entropies. (C) 1999 Academic Press. C1 BDM Petr Technol, Bartlesville Thermodynam Grp, Bartlesville, OK 74005 USA. RP Chirico, RD (reprint author), NIST, 100 Bur Dr,MS 8381, Gaithersburg, MD 20899 USA. NR 31 TC 0 Z9 1 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 MAR PY 1999 VL 31 IS 3 BP 323 EP 337 DI 10.1006/jcht.1998.0452 PG 15 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 179PA UT WOS:000079336200002 ER PT J AU Chirico, RD Knipmeyer, SE Nguyen, A Steele, WV AF Chirico, RD Knipmeyer, SE Nguyen, A Steele, WV TI Thermodynamic properties of the methylpyridines. Part 2. Vapor pressures, heat capacities, critical properties, derived thermodynamic functions between the temperatures 250 K and 560 K, and equilibrium isomer distributions for all temperatures >= 250 K SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Review DE vapor pressure; heat capacity; critical properties; density; isomerization equilibria ID ORGANIC NITROGEN-COMPOUNDS; 3RD VIRIAL-COEFFICIENT; XYLENE ISOMERIZATION; RECOMMENDED VALUES; PYRIDINE; DENSITIES; ENTHALPIES; SPECTRA; 2-METHYLPYRIDINE; RECONCILIATION AB Results are reported for measurements leading to the calculation of standard thermodynamic properties for temperatures from T = 250 K to T = 560 K for the methylpyridines (Chemical Abstracts registry numbers: 4-methylpyridine, 108-89-4; 2-methylpyridine, 109-06-8; 3-methylpyridine, 108-99-6). The standard state is defined as the ideal gas at the pressure p = p(O) = 101.325 kPa. Vapor pressures were measured by comparative ebulliometry for the pressure range p approximate to 4 kPa to p = 270 kPa. Two-phase (liquid + vapor) heat capacities were measured for the temperature range approximate to 310 (T/K) approximate to 590 with a differential scanning calorimeter (d.s.c.), and saturation heat capacities C-sat were derived. The critical temperature T, was determined experimentally by d.s.c., and the critical pressure and critical density were derived. Densities for the liquid phase of 3-methylpyridine at saturation pressure were measured with a vibrating-tube densimeter for the temperatures 323 (T/K) < 473. The enthalpy of combustion for 3-methylpyridine was determined to resolve a discrepancy in the literature. Enthalpies of vaporization were calculated for all compounds. Literature values for enthalpy increments and entropies for the condensed phases by adiabatic heat-capacity calorimetry and the energies of combustion were combined with the present results to derive standard entropies, enthalpy increments, and molar Gibbs free energies of formation for temperatures between T = 250 K and T = 560 K. Comparisons with standard entropies calculated statistically provide corroboration for the calorimetrically derived values and are used to demonstrate thermodynamic consistency for properties related through identities and correlations. Isomerization distributions derived with standard molar Gibbs free energies of formation are used to aid interpretation of literature fossil fuel characterization and pyridine methylation catalysis studies. (C) 1999 Academic Press. C1 BDM Petr Technol, Bartlesville Thermodynam Grp, Bartlesville, OK 74005 USA. RP Chirico, RD (reprint author), NIST, 100 Bur Dr,MS 8381, Gaithersburg, MD 20899 USA. EM chirico@nist.gov NR 103 TC 23 Z9 23 U1 2 U2 3 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 MAR PY 1999 VL 31 IS 3 BP 339 EP 378 DI 10.1006/jcht.1998.0451 PG 40 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 179PA UT WOS:000079336200003 ER PT J AU Higgins, RW Chen, Y Douglas, AV AF Higgins, RW Chen, Y Douglas, AV TI Interannual variability of the North American warm season precipitation regime SO JOURNAL OF CLIMATE LA English DT Article ID LOW-LEVEL JET; SOUTHERN OSCILLATION; UNITED-STATES; MEXICAN MONSOON; CLIMATOLOGY; SURFACE; SYSTEM; ENSO AB Interannual variability of the North American warm season-precipitation regime is examined in three regions of the United Stares and Mexico: Arizona-New Mexico, northwest Mexico, and southwest Mexico. Daily observed precipitation over the United States and Mexico for a 26-yr (1963-88) period and various fields from the National Centers for Environmental Prediction-National Center for Atmospheric Research Reanalysis are used to compare and contrast hydrologic conditions and atmospheric circulation features associated with early, late, wet, and dry monsoons in each region. Relationships between anomalous monsoon behavior and the El Nino-Southern Oscillation phenomenon are examined. Some factors associated with the atmosphere's lower boundary conditions that might influence the interannual variability of the warm season precipitation regime are discussed. The mean seasonal evolution of the North American monsoon system is characterized by the regular northward progression of heavy precipitation from southern Mexico by early June to the southwestern United States by early July. While the seasonal normal rainfall and its variability are largest in southwest Mexico, the mean seasonal percent departure from normal is largest in Arizona-New Mexico. Wet (dry) monsoons in southwest Mexico tend to occur during La Nina (El Nino). This association is attributed, in part, to the impact of local sea surface temperature anomalies on the land-sea thermal contrast, hence the strength of the monsoon. There is also a weak association between dry monsoons in Arizona-New Mexico (northwest Mexico) and La Nina (El Nino). Wet summer monsoons in Arizona-New Mexico tend to follow winters characterized by dry conditions in the southwestern United States and vice versa. Although the onset and duration of the monsoon are guile regular in each region, the precise dare of onset in a given region is highly variable and likely to he unrelated to the date of onset in the other regions. Early monsoons in Arizona-New Mexico tend to have heavy seasonal rainfall while late monsoons in northwest Mexico tend to have deficient seasonal rainfall. The onset date in southwest Mexico is not related to seasonal rainfall. However, interannual fluctuations in rainfall over the entire monsoon region for the 2-month period after onset in southwest Mexico are highly correlated, suggesting that knowledge of the starting dare in southwest Mexico may be useful for analyzing, understanding, and possibly predicting these fluctuations. C1 NOAA, Climate Predict Ctr, NWS, NCEP, Washington, DC 20233 USA. Res & Data Syst Corp, Greenbelt, MD USA. Creighton Univ, Dept Atmospher Sci, Omaha, NE 68178 USA. RP Higgins, RW (reprint author), NOAA, Climate Predict Ctr, NWS, NCEP, W-NP52,5200 Auth Rd,Room 605, Washington, DC 20233 USA. NR 34 TC 155 Z9 158 U1 0 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 MAR PY 1999 VL 12 IS 3 BP 653 EP 680 DI 10.1175/1520-0442(1999)012<0653:IVOTNA>2.0.CO;2 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 176ZE UT WOS:000079181700001 ER PT J AU Gaffen, DJ Ross, RJ AF Gaffen, DJ Ross, RJ TI Climatology and trends of US surface humidity and temperature SO JOURNAL OF CLIMATE LA English DT Article ID TROPOSPHERIC WATER-VAPOR; TROPICAL WESTERN PACIFIC; UNITED-STATES; ATMOSPHERIC MOISTURE; MINIMUM TEMPERATURE; RELATIVE-HUMIDITY; HIGH-LATITUDES; OCEAN; PRECIPITATION; VARIABILITY AB Climatological annual and seasonal dewpoint, specific humidity, and relative humidity maps for the United States are presented using hourly data from 188 first-order weather stations for the period 1961-90. Separate climatologies were calculated for daytime (three observations per day between 0800 and 1600 LST), nighttime (three observations per day between 2000 and 0400 LST), and the full day (eight observations per day, every 3 h). With extended datasets for the period 1961-95, trends in these same variables and temperature are calculated for each of 170 stations and for eight regions of the country. The data show increases in specific humidity of several percent per decade, and increases in dewpoint of several tenths of a degree per decade, over most of the country in winter, spring, and summer. Nighttime humidity trends are larger than daytime trends. The specific humidity increases are consistent with upward temperature trends. The upward temperature and humidity trends are also consistent with upward trends in apparent temperature, a measure of human comfort based on temperature and humidity. Relative humidity trends are weaker than the specific humidity trends, but they do show evidence of increases, especially in winter and spring. The possibility that the detected trends may be artifacts of changes in instrumentation was examined, but several lines of reasoning suggest that they are not. Anthropogenic water vapor produced from fossil fuel consumption, both locally and globally, is too small a source to explain the observed trends. C1 NOAA, Air Resources Lab, Environm Res Labs, REAR, Silver Spring, MD 20910 USA. RP NOAA, Air Resources Lab, Environm Res Labs, REAR, SSMC3,1315 East West Highway, Silver Spring, MD 20910 USA. EM dian.gaffen@noaa.gov NR 55 TC 123 Z9 126 U1 1 U2 12 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD MAR PY 1999 VL 12 IS 3 BP 811 EP 828 DI 10.1175/1520-0442(1999)012<0811:CATOUS>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 176ZE UT WOS:000079181700009 ER PT J AU Barilo, SN Shiryaev, SV Gatalskaya, VI Zhigunov, DI Pushkarev, AV Fedotova, VV Szymczak, H Szymczak, R Baran, M Lynn, JW Rosov, N Skanthakumar, S AF Barilo, SN Shiryaev, SV Gatalskaya, VI Zhigunov, DI Pushkarev, AV Fedotova, VV Szymczak, H Szymczak, R Baran, M Lynn, JW Rosov, N Skanthakumar, S TI A new method for growing Ba1-xKxBiO3 single crystals and investigation of their properties SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 12th International Conference on Crystal Growth, held in Conjunction with the 10th International Conference on Vapor Growth and Epitaxy (ICCG-12/ICVGE-10) CY JUL 26-31, 1998 CL JERUSALEM, ISRAEL DE Ba1-xKxBiO3; single crystal; electrochemical deposition; neutron scattering; magnetisation; vortex lattice ID GROWTH; SUPERCONDUCTIVITY AB Large single crystals of the copper-free Ba1-xKxBiO3 (BKBO) superconductor have been successfully grown using modified method of electrochemical deposition, For the first time we employed the method of growth where a BaBiO3 single crystal plate was used as a seed. A BKBO layer with(1 0 0) orientation and similar to 1 mm thick grown on the substrate was cut off and thereafter used as a secondary seed. We used a dynamic method, i.e., a crystal bolder with reciprocating motion to homogenize the potassium distribution over the crystal volume. The maximum volume of the as-grown crystals reached similar to 2 cm(3) with the FWHM of the Bragg reflection curves not exceeding 1 degrees. The lattice structure of the Abrikosov vortices as well as the character of defects of the Ba0.6K0.4BiO3 single crystal, caused by the growth technique, has been studied by small-angle neutron scattering. From SQUID magnetisation measurements, the growth-induced anisotropy of hysteresis loops and pinning force of the second-order superconductor are reported. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Acad Sci, Inst Phys Solids & Semicond, Minsk 220072, Byelarus. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20899 USA. RP Barilo, SN (reprint author), Natl Acad Sci, Inst Phys Solids & Semicond, 17 P Brovka St, Minsk 220072, Byelarus. EM bars@ifttp.bas-net.by NR 12 TC 7 Z9 7 U1 2 U2 18 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 MAR PY 1999 VL 198 BP 636 EP 641 DI 10.1016/S0022-0248(98)01201-9 PN 1 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 187ZM UT WOS:000079819000116 ER PT J AU Seidensticker, RG Rosch, WR Mazelsky, R Hopkins, RH Singh, NB Coriell, SR Duval, WMB Batur, C AF Seidensticker, RG Rosch, WR Mazelsky, R Hopkins, RH Singh, NB Coriell, SR Duval, WMB Batur, C TI Active control of interface shape during the crystal growth of lead bromide SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 12th International Conference on Crystal Growth, held in Conjunction with the 10th International Conference on Vapor Growth and Epitaxy (ICCG-12/ICVGE-10) CY JUL 26-31, 1998 CL JERUSALEM, ISRAEL DE crystal; model; lead bromide; solid-liquid interface; furnace AB A thermal model for predicting and designing the furnace temperature profile was developed and used for the crystal growth of lead bromide. The model gives the ampoule temperature as a function of the furnace temperature, thermal conductivity, heat transfer coefficients, and dimensions as variable parameters. Crystal interface curvature was derived from the model and it was compared with the predicted curvature for a particular furnace temperature and growth parameters. Large crystals of lead bromide were grown and it was observed that interface shape was in agreement with the shape predicted by this model. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Northrop Grumman Corp, ESSD, STC, Pittsburgh, PA 15235 USA. NIST, Div Met, Gaithersburg, MD 20899 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Singh, NB (reprint author), Northrop Grumman Corp, ESSD, STC, 1350 Beulah Rd, Pittsburgh, PA 15235 USA. EM Singh.n.b@postal.essd.northgrum.com NR 5 TC 7 Z9 7 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 MAR PY 1999 VL 198 BP 988 EP 994 DI 10.1016/S0022-0248(98)01213-5 PN 2 PG 7 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 187ZP UT WOS:000079819300020 ER PT J AU Singh, NB Henningsen, T Suhre, DR Rosch, W Hopkins, RH Mazelsky, R Coriell, SR Duval, WMB AF Singh, NB Henningsen, T Suhre, DR Rosch, W Hopkins, RH Mazelsky, R Coriell, SR Duval, WMB TI Hg2Cl2 crystals for efficient birefringence etalon filters SO JOURNAL OF CRYSTAL GROWTH LA English DT Article; Proceedings Paper CT 12th International Conference on Crystal Growth, held in Conjunction with the 10th International Conference on Vapor Growth and Epitaxy (ICCG-12/ICVGE-10) CY JUL 26-31, 1998 CL JERUSALEM, ISRAEL DE mercurous chloride; etalon; vapor growth; halides; filter; birefringence AB We have experimentally demonstrated the physical vapor transport growth of 30 mm diameter and 8 cm long mercurous chloride crystals for birefringence etalon filters. The [1 1 0] oriented seeded crystals were grown in a two zone vertical transparent furnace by vapor phase transport method. Two 5 mm and 1.5 mm thick filters were fabricated and tested interferometrically and with a spectrometer. The filter exhibited the spectral modulation expected based on the filter thickness. The effect of temperature on filter performance was studied by measuring the filter operation at specific calibrated temperatures. We observed a significant shift in filter wavelength at 25.8 degrees C and 29.8 degrees C. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Northrop Grumman Corp, Ctr Sci & Technol, Pittsburgh, PA 15235 USA. NIST, Div Met, Gaithersburg, MD 20899 USA. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Singh, NB (reprint author), Northrop Grumman Corp, Ctr Sci & Technol, 1350 Beulah Rd, Pittsburgh, PA 15235 USA. EM singh.n.b@postal.essd.northgrum.com NR 3 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 MAR PY 1999 VL 198 BP 995 EP 998 DI 10.1016/S0022-0248(98)01211-1 PN 2 PG 4 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 187ZP UT WOS:000079819300021 ER PT J AU Mueller, HJ Eichmiller, FC AF Mueller, HJ Eichmiller, FC TI Untitled SO JOURNAL OF DENTAL RESEARCH LA English DT Letter C1 Natl Inst Stand & Technol, Paffenbarger Res Ctr, Amer Dent Assoc Hlth Fdn, Gaithersburg, MD 20899 USA. RP Mueller, HJ (reprint author), Natl Inst Stand & Technol, Paffenbarger Res Ctr, Amer Dent Assoc Hlth Fdn, 100 Bureau Dr Stop 8546, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 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 MAR PY 1999 VL 78 IS 3 BP 724 EP 724 PG 1 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 177AD UT WOS:000079184100001 PM 10096444 ER PT J AU Jung, YG Peterson, IM Pajares, A Lawn, BR AF Jung, YG Peterson, IM Pajares, A Lawn, BR TI Contact damage resistance and strength degradation of glass-infiltrated alumina and spinel ceramics SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE alumina; cracking; deformation; dental ceramics; Hertzian contact; microstructure; spinel; strength ID INDENTATION FLAWS; FRACTURE; FATIGUE; SHARP AB All-ceramic crowns are coming into widespread use because of their superior esthetics and chemical inertness. This study examines the hypothesis that glass-infiltrated alumina and spinel core ceramics are resistant to damage accumulation and strength degradation under representative oral contact conditions. Accordingly, Hertzian indentation testing with hard spheres is used to evaluate damage accumulation in alumina and spinel ceramics with different pre-form grain morphologies and porosities. Indentation stress-strain curves measured on fully infiltrated materials reveal a marked insensitivity to the starting pre-form state. The glass phase is shown to play a vital role in providing mechanical rigidity and strength to the ceramic structures. All the infiltrated ceramics show subsurface cone fracture and quasi-plastic deformation above critical loads Pc (cracking) and Py (yield), depending on sphere radius, with P-Y < P-C. Strength degradation from accumulation of damage in Hertzian contacts above these critical loads is conspicuously small, suggesting that the infiltrated materials should be highly damage-tolerant to the "blunt" contacts encountered during mastication. Failure in the strength tests originates from either cone cracks ("brittle mode") or yield zones ("quasi-plastic mode"), with the brittle mode more dominant in the spinels and the quasi-plastic mode more dominant in the aluminas. Multi-cycle contacts at lower loads, but still above loads typical of oral function, are found to be innocuous up to 10(5) cycles in air and water, although contacts at 10(6) cycles in water do cause significant strength degradation. By contrast, contacts with Vickers indenters produce substantial strength losses at low loads, suggesting that the mechanical integrity of these materials may be compromised by inadvertent "sharp" contacts. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Lawn, BR (reprint author), NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RI Pajares, Antonia/I-3881-2015 OI Pajares, Antonia/0000-0002-1086-7586 FU NIDCR NIH HHS [P01 DE10976] NR 45 TC 40 Z9 41 U1 1 U2 7 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 MAR PY 1999 VL 78 IS 3 BP 804 EP 814 PG 11 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 177AD UT WOS:000079184100014 PM 10096457 ER PT J AU Rao, MV Tucker, J Holland, OW Papanicolaou, N Chi, PH Kretchmer, JW Ghezzo, M AF Rao, MV Tucker, J Holland, OW Papanicolaou, N Chi, PH Kretchmer, JW Ghezzo, M TI Donor ion-implantation doping into SiC SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT 40th Electronic Materials Conference (EMC-40) CY JUN 24-26, 1998 CL UNIV VIRGINIA, CHARLOTTESVILLE, VIRGINIA SP TMS HO UNIV VIRGINIA DE activation; annealing; donors; ion-implantation; SiC ID SILICON-CARBIDE; NITROGEN; IMPURITIES; PHOSPHORUS AB In this paper, dopant electrical activation and dopant thermal stability results of As and Sb-implanted GH-Sie epitaxial layers and N ion implantations into bulk semi-insulating (SI) 4H-SiC are presented. In addition, empirical formulas for the first four statistical moments (range, straggle, skewmess, and kurtosis) of the implant depth distributions of N and P ion implants are developed in the energy range of 50 keV to 4 MeV. The nitrogen ion-implantations in SI 4H-SiC yield an acceptable (27%) room-temperature electrical activation (ratio of measured sheet-carrier concentration at room-temperature to the implant dose) for N concentrations of 2 x 10(19) cm(-3). The As and Sb implants out-diffuse during annealing and yield low (<20%) room-temperature electrical activation for implant concentrations of 10(19) cm(-3). The N and P implant depth distributions in SiC can be simulated using the Pearson IV distribution function and the range statistics provided by the empirical formulas. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. GE, Corp Res & Dev, Schenectady, NY 12301 USA. RP Rao, MV (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. NR 33 TC 13 Z9 14 U1 4 U2 6 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD MAR PY 1999 VL 28 IS 3 BP 334 EP 340 DI 10.1007/s11664-999-0036-8 PG 7 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 177ZB UT WOS:000079240000036 ER PT J AU Hanson, PJ Zdanowicz, VS AF Hanson, PJ Zdanowicz, VS TI Elemental composition of otoliths from Atlantic croaker along an estuarine pollution gradient SO JOURNAL OF FISH BIOLOGY LA English DT Article DE otoliths; Micropogonias undulatus; elemental composition; pollution gradient ID PLEURONECTES-PLATESSA L; MICROPOGONIAS-UNDULATUS; STOCK IDENTIFICATION; FISH; DISCRIMINATION; MICROCHEMISTRY; SEDIMENTS; CHEMISTRY; MOVEMENTS; SAGITTAE AB Elemental compositions of otoliths of young-of-the-year Atlantic croaker Minopogonias undulatus at stations along a pollution gradient in Galveston Bay, Texas, were compared with those of sediments and livers to establish the level of consonance between otolith and habitat chemistries. Both coupled and uncoupled trends were indicated, with the bulk of the results pointing to the need for additional research to test the working hypothesis that the otolith stores a temporal record of elemental chemistry of resident waters. Lack of simple correlations between elemental concentrations in sediment or liver and in otoliths indicate that other biological and geochemical factors influence otolith composition. (C) 1999 The Fisheries Society of the British Isles. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Ctr, Beaufort Lab, Beaufort, NC 28516 USA. NE Fisheries Sci Ctr, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Hanson, PJ (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Ctr, Beaufort Lab, Beaufort, NC 28516 USA. EM peter.hanson@noaa.gov; vincent.zdanowicz@noaa.gov NR 29 TC 33 Z9 37 U1 2 U2 9 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD MAR PY 1999 VL 54 IS 3 BP 656 EP 668 PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 174CM UT WOS:000079016600016 ER PT J AU Papadopoulos, G William, MM AF Papadopoulos, G William, MM TI A generic centerline velocity decay curve for initially turbulent axisymmetric jets SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article ID MIXING BEHAVIOR; FIELD; DENSITY; NUMBER; FLOW AB Recently the authors introduced a length scale which effectively collapsed the near field centerline development of velocity and mass fraction for variable density axisymmetric jets whose initial conditions correspond to those of fully developed turbulent pipe flow. The new length scale incorporated the initial mass, momentum, and turbulence intensity per unit al-ea to capture the Reynolds number dependence of near field development for the velocity and scalar distributions observed in low Reynolds number turbulent jets. The present paper extends the analysis for a constant density jet to the intermediate and self-similar far fields further downstream using a dynamic length scale based on the local centerline turbulence intensity The normalized mean velocity distributions of an air jet collapse over the entire flow distance investigated when the axial distance is normalized by the proposed length scale, thus scaling the virtual origin shift and effectively incorporating the Reynolds number dependence. C1 NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Papadopoulos, G (reprint author), Dantec Measurement Technol Inc, 777 Corp Dr, Mahwah, NJ 07430 USA. NR 26 TC 15 Z9 16 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD MAR PY 1999 VL 121 IS 1 BP 80 EP 85 DI 10.1115/1.2822016 PG 6 WC Engineering, Mechanical SC Engineering GA 182TB UT WOS:000079513300009 ER PT J AU Galand, M Richmond, AD AF Galand, M Richmond, AD TI Magnetic mirroring in an incident proton beam SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID H-ATOM FLUXES; AURORAL PROTON; TRANSPORT; MODEL; PRECIPITATION; ATMOSPHERE; ION AB We point out that the influence of magnetic-field nonuniformity on redirecting the pitch angle of a particle is independent of the particle's charge and thus is identical for protons and neutral hydrogen atoms. Under certain circumstances one can then speak of "magnetic mirroring" of hydrogen atoms as well as of protons. In the case of an energetic proton beam incident on the upper atmosphere, the study of the influence of magnetic field on both protons and H atoms can be relevant to inferring information about proton aurora from measurements of upgoing energetic particles observed from space. In a model that here neglects collisional angular redistribution of the particles, the total particle and energy albedos are approximately independent of the energy of the incident particles and of the atmospheric temperature. However, the separate proton and H atom albedos have a strong dependence on the incident energy. We also reinvestigate how to handle energy conservation properly in the presence of a nonuniform magnetic field, to provide a good validation for proton transport models. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. RP Galand, M (reprint author), NOAA, Space Environm Ctr, 325 Broadway, Boulder, CO 80303 USA. RI Galand, Marina/C-6804-2009 NR 22 TC 23 Z9 23 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 1999 VL 104 IS A3 BP 4447 EP 4455 DI 10.1029/1998JA900123 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 171NK UT WOS:000078870000020 ER PT J AU Li, XL Baker, DN Teremin, M Cayton, TE Reeves, GD Selesnick, RS Blake, JB Lu, G Kanekal, SG Singer, HJ AF Li, XL Baker, DN Teremin, M Cayton, TE Reeves, GD Selesnick, RS Blake, JB Lu, G Kanekal, SG Singer, HJ TI Rapid enhancements of relativistic electrons deep in the magnetosphere during the May 15, 1997, magnetic storm SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID RADIATION BELT; ENERGETIC PARTICLES; SOLAR; WIND; ACCELERATION; DIFFUSION; SAMPEX; ORBIT AB Variations in 0.2-3.2 MeV electron flux in the magnetosphere during the May 15, 1997, magnetic storm (the largest magnetic storm of 1997) arc examined. After over an order of magnitude initial decrease of the 0.2-3.2 MeV electron fluxes, the 0.2-0.8 MeV electron flux at L < 4.5 increased and surpassed the prestorm level in an hour. This increase was followed by increases of the more energetic 0.8-3.2 MeV electron fluxes. These energetic electron variations are examined utilizing data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), the Global Positioning System (GPS) series of satellites, and the Los Alamos National Laboratory (LANL) sensors on board geosynchronous satellites. During the main phase of the storm, fluxes of >0.4-MeV electrons from SAMPEX decreased at L > 4.5 following the D-st drop but increased somewhat at L < 4. GPS satellite data also show that the electron flux decreased in the energy range 0.2-3.2 MeV for all L values above the minimum detectable L value of similar to 4.2 simultaneously with the decrease in D-st, which is consistent with an adiabatic process. However, the recovery of the electron flux was different at different energies, with an earlier recovery of the less energetic electrons and a later recovery of the more energetic electrons. The recovery of the electron fluxes started before the recovery of D-st, indicating that nonadiabatic processes were involved. The 0.2- to 0.8-MeV electrons appeared in the low-L region (4.2-4.5) at about the same time that the GOES 9 spacecraft measured a strong dipolarization of the Earth's stretched magnetic field. Outer zone electron fluxes continued to increase across a wide L range (L = 3-8) though the electron flux exhibited a strong spatial gradient, with the peak flux below L = 4.2 in the equatorial plane. These data are used to test the idea if radial transport from larger L can account for all of the increase in the flux in the heart of the outer zone electron radiation belt at L = 4-5. However, the radial gradient of the phase space density for a given first adiabatic invariant was estimated to be: negative as a function of radial distance during the time that the electron flux was increasing. This estimate is somewhat uncertain because of rapid temporal variations and sparse data. However, if this estimate is correct, the usual theory of radial transport from larger radial distances cannot account fur all of the increase in the electron flux. The analysis thus suggests that another process, such as local heating, which does not conserve mu, may be required to explain the subsequent enhancement of the more energetic (0.8- to 3.2-MeV) electrons but that additional data are required to answer this question definitely. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Aerospace Corp, Dept Space Sci, Los Angeles, CA 90009 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Li, XL (reprint author), Univ Colorado, Atmospher & Space Phys Lab, 1234 Innovat Dr, Boulder, CO 80303 USA. RI Lu, Gang/A-6669-2011; Reeves, Geoffrey/E-8101-2011 OI Reeves, Geoffrey/0000-0002-7985-8098 NR 40 TC 41 Z9 44 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 1999 VL 104 IS A3 BP 4467 EP 4476 DI 10.1029/1998JA900092 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 171NK UT WOS:000078870000022 ER PT J AU Sibeck, DG Borodkova, NL Schwartz, SJ Owen, CJ Kessel, R Kokubun, S Lepping, RP Lin, R Luhr, H McEntire, RW Meng, CI Mukai, T Nemecek, Z Parks, G Phan, TD Romanov, SA Safrankova, J Sauvaud, JA Singer, HJ Solovyev, SI Szabo, A Takahashi, K Williams, DJ Yumoto, K Zastenker, GN AF Sibeck, DG Borodkova, NL Schwartz, SJ Owen, CJ Kessel, R Kokubun, S Lepping, RP Lin, R Luhr, H McEntire, RW Meng, CI Mukai, T Nemecek, Z Parks, G Phan, TD Romanov, SA Safrankova, J Sauvaud, JA Singer, HJ Solovyev, SI Szabo, A Takahashi, K Williams, DJ Yumoto, K Zastenker, GN TI Comprehensive study of the magnetospheric response to a hot flow anomaly SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID EARTHS BOW SHOCK; UPSTREAM PRESSURE VARIATIONS; MAGNETIC-FIELD SIGNATURES; LATITUDE BOUNDARY-LAYER; WIND DYNAMIC PRESSURE; SOLAR-WIND; MAGNETOPAUSE MOTION; SATELLITE-OBSERVATIONS; DIAMAGNETIC CAVITIES; INTERBALL PROJECT AB We present a comprehensive observational study of the magnetospheric response to an interplanetary magnetic field (IMF) tangential discontinuity, which first struck the postnoon bow shock and magnetopause and then swept past the prenoon bow shock and magnetopause on July 24, 1996. Although unaccompanied by any significant plasma variation, the discontinuity interacted with the bow shock to form a hot flow anomaly (HFA), which was observed by Interball-1 just upstream from the prenoon bow shock. Pressures within and Earthward of the HFA were depressed by an order of magnitude, which allowed the magnetopause to briefly (similar to 7 min) move outward some 5 R-E beyond its nominal position and engulf Interball-1. A timing study employing nearby Interball-1 and Magion-4 observations demonstrates that this motion corresponded to an antisunward and northward moving wave on the magnetopause. The same wave then engulfed Geotail, which was nominally located downstream in the outer dawn magnetosheath. Despite its large amplitude, the wave produced only minor effects in GOES-8 geosynchronous observations near local dawn. Polar Ultraviolet Imager (UVI) observed a sudden brightening of the afternoon aurora, followed by an even more intense transient brightening of the morning aurora. Consistent with this asymmetry, the discontinuity produced only weak near-simultaneous perturbations in high-latitude postnoon ground magnetometers but a transient convection vortex in the prenoon Greenland ground magnetograms. The results of this study indicate that the solar wind interaction with the bow shock is far more dynamic than previously imagined and far more significant to the solar wind-magnetosphere interaction. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Moscow Space Res Inst, Moscow 117810, Russia. Univ London Queen Mary & Westfield Coll, Astron Unit, London E1 4NS, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Solar Terr Environm Lab, Aichi 332, Japan. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 229, Japan. Charles Univ, Fac Math & Phys, Dept Elect & Vacuum Phys, CR-18000 Prague, Czech Republic. Univ Washington, Geophys Program, Seattle, WA 98195 USA. Ctr Etud Spatiale Rayonnements, CNRS, F-31029 Toulouse, France. NOAA, Space Environm Lab, Boulder, CO 80303 USA. Inst Cosmophys Res & Aeron, Yakutsk 677891, Russia. Kyushu Univ, Dept Earth & Planetary Sci, Fukuoka 812, Japan. RP Sibeck, DG (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. RI Owen, Christopher/C-2999-2008; Sibeck, David/D-4424-2012; Liou, Kan/C-2089-2016 OI Owen, Christopher/0000-0002-5982-4667; Liou, Kan/0000-0001-5277-7688 NR 69 TC 95 Z9 96 U1 1 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 MAR 1 PY 1999 VL 104 IS A3 BP 4577 EP 4593 DI 10.1029/1998JA900021 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 171NK UT WOS:000078870000031 ER PT J AU Krishnakumar, PK Casillas, E Snider, RG Kagley, AN Varanasi, U AF Krishnakumar, PK Casillas, E Snider, RG Kagley, AN Varanasi, U TI Environmental contaminants and the prevalence of hemic neoplasia (leukemia) in the common mussel (Mytilus edulis complex) from Puget sound, Washington, USA SO JOURNAL OF INVERTEBRATE PATHOLOGY LA English DT Article DE Mytilus edulis; hemic neoplasia; microencapsulated contaminants; PAHs; Aroclor 1254; PCBs ID N-NITROSO COMPOUNDS; MARINE MUSSEL; MYA-ARENARIA; HEMOCYTIC CONDITION; BIVALVE MOLLUSKS; DIGESTIVE CELLS; BAY MUSSELS; LIGHT; HYDROCARBONS; SEASONALITY AB The relationship between hemic neoplasia, a blood cell disorder in bivalve molluscs, and chemical contaminants was evaluated in the common mussel (Mytilus edulis complex). Hemic neoplasia (HN) is endemic to mussel populations in Puget Sound. The prevalence of hemic neoplasia ranged from 0 to 30% in mussels from nine sites in Puget Sound, Washington. Organic chemical contamination in sediment from these sites range from 0.1 to 64.0 ppm of polycyclic aromatic hydrocarbons (PAHs) and 0.07 to 0.50 ppm chlorinated hydrocarbons. No relationship between the body burden of environmental contaminants and the prevalence of HN in mussels was identified. To evaluate the shortterm ability of chemical contaminants to induce HN in mussels, mussels, from a site where mussels were previously determined to be HN free, were fed microencapsulated PAHs (composed of a mixture of phenanthrene, flouranthene, and benzo[a]pyrene) or PCBs (Aroclor 1254) and the prevalence of HN was assessed after 30 days of exposure. Although an apparent in crease in HN prevalence (20 to 30%) was observed in all treatments groups except the untreated controls, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. A long-term (180-day) exposure study was conducted to evaluate the influence of PAHs or PCBs in modulating the prevalence of HN in a mussel population already exhibiting a moderate HN prevalence. Mussels, from a site where mussels were previously determined to exhibit a background prevalence of HN, fed microencapsulated PAHs, PCBs, and corn oil (vehicle) over a long time period (180 days), revealed an apparent increased prevalence of HN (30 to 40%) above the low levels (20%) initially present. However, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. Although chemical contaminants have been proposed as a modulating factor in the development and promotion of HN in bivalve molluscs from environmentally stressed and degraded habitats, we find no evidence that chemical contaminants induce or promote the development of HN in the mussel M. edulis complex. (C) 1999 Academic Press. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Div Environm Conservat, Seattle, WA 98112 USA. Cent Marine Fisheries Res Inst, Res Ctr, Mangalore 575001, India. RP Krishnakumar, PK (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Div Environm Conservat, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 35 TC 25 Z9 25 U1 0 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2011 J9 J INVERTEBR PATHOL JI J. Invertebr. Pathol. PD MAR PY 1999 VL 73 IS 2 BP 135 EP 146 DI 10.1006/jipa.1998.4798 PG 12 WC Zoology SC Zoology GA 176QU UT WOS:000079163900001 PM 10066393 ER PT J AU Fry, RA Bennett, LH Della Torre, E Shull, RD Egelhoff, WF Farrow, RFC Lee, CH AF Fry, RA Bennett, LH Della Torre, E Shull, RD Egelhoff, WF Farrow, RFC Lee, CH TI Magneto-optical measurements of Co-Pt (111) multilayers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 7th International Conference on Magnetic Recording Media (MRM 98) CY AUG 30-SEP 02, 1998 CL MAASTRICHT, NETHERLANDS SP Commiss European Union, Koninklijke Nederlandse Akad Wetenschappen, Univ Twente, MESA Res Inst, ADE, BPS, Magnet Storage Div, BF Goodrich Specialty Chem, Estane Thermoplast Polyurethanes Div, Elsevier Sci BV, EMTECH Magnet GmbH, Hewlett-Packard, comp Peripherals, Imation, Japan Recording-Media Ind Assoc, MPO, OnStream BV, Oxford Instruments, Philips Res DE magneto-optics; multilayers; Kerr effect; perpendicular magnetization ID BEAM-EPITAXIAL-GROWTH; CO/PT-MULTILAYERS; SUPERLATTICES; AXES AB An automated magneto-optical Kerr effect (MOKE) magnetometer was used to measure polar Kerr rotation (theta(K)) and ellipticity (epsilon(K)) loops of (0.3 nm Co/x Pt)(15) multilayers with x = 0.3 to 1.2 nm. For most samples studied, the hysteresis loops exhibit typical perpendicular magnetization characteristics. The loops have unit squareness, and the normalized behavior of theta(K) and epsilon(K) is identical. However, for two samples with composition near (0.3 nm Co/1.0 nm Pt)(15), the theta(K) and epsilon(K) loops are no longer identical, and exhibit bimodal features. Using MOKE major hysteresis loops and first-order reversal curves, a plausible explanation for this behavior is presented. (C) 1999 Elsevier Science B.V. All rights reserved. C1 George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20988 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. IBM Corp, Storage Syst Div, San Jose, CA 95193 USA. RP Fry, RA (reprint author), George Washington Univ, Inst Magnet Res, 20101 Acad Way, Ashburn, VA 22011 USA. NR 17 TC 8 Z9 8 U1 0 U2 3 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 1999 VL 193 IS 1-3 BP 162 EP 165 DI 10.1016/S0304-8853(98)00423-5 PG 4 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 175PY UT WOS:000079104600038 ER PT J AU Ghosh, G Vaynman, S Fine, ME Hsu, SM AF Ghosh, G Vaynman, S Fine, ME Hsu, SM TI Microstructure and ambient properties of a Sialon composite prepared by hot pressing and reactive sintering of beta-Si3N4 coated with Al2O3 SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID SILICON-NITRIDE CERAMICS; INTERGRANULAR FILM THICKNESS; R-CURVE BEHAVIOR; AL-O-N; GRAIN-BOUNDARY; MECHANICAL-PROPERTIES; FRACTURE-TOUGHNESS; PHASE; ALUMINA; SI3N4 AB A composite microstructure, consisting of beta-Sialon, O-Sialon, and X-Sialon phases was produced by coating beta-Si3N4 particles with amorphous alumina followed by hot pressing and reactive sintering at 1923 K. The particle coating procedure was selected over conventional powder blending in order to promote heterogeneous nucleation of beta-Sialon grains on beta-Si3N4 particles uniformly. The microstructure, chemistry of the phases, and interphase interfaces of this ceramic were characterized by transmission electron microscopy (TEM) and high-resolution analytical electron microscopy (AEM). Both electron energy-loss spectroscopy (EELS) and energy-dispersive spectroscopy (EDS) x-ray microanalysis in AEM revealed that beta-Sialon grains had varying aluminum and oxygen contents. High-resolution electron microscopy (HREM) examination of several interphase interfaces and triple junctions suggests that the amount of glassy phase in the produced ceramic is substantially lower compared to those reported in the literature. This is of importance of high temperature properties, The fracture toughness and wear properties were evaluated at room temperature. Available data indicate that the fracture toughness and wear of beta-Sialon composite can be significantly improved by the powder coating technique compared to the conventional powder blending technique. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NIST, Gaithersburg, MD 20899 USA. RP Northwestern Univ, Dept Mat Sci & Engn, 2225 N Campus Dr, Evanston, IL 60208 USA. RI Vaynman, Semyon/B-7538-2009; Ghosh, Gautam/B-7517-2009; Fine, Morris/B-7516-2009 NR 65 TC 5 Z9 5 U1 0 U2 4 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 1999 VL 14 IS 3 BP 881 EP 890 DI 10.1557/JMR.1999.0118 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 235PB UT WOS:000082550300033 ER PT J AU FitzGerald, SA Neumann, DA Rush, JJ Kirkpatrick, RJ Cong, X Livingston, RA AF FitzGerald, SA Neumann, DA Rush, JJ Kirkpatrick, RJ Cong, X Livingston, RA TI Inelastic neutron scattering study of the hydration of tricalcium silicate SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CALCIUM SILICATE; RAMAN-SPECTROSCOPY; HYDROXIDE; PASTES AB Inelastic neutron scattering is applied for the first time to monitor directly the concentration of calcium hydroxide formed during the hydration of tricalcium silicate. Results taken between 10 and 40 degrees C show that the onset of calcium hydroxide formation is delayed at lower temperatures but that the final quantity formed appears to be converging to a temperature-independent value. At 20 degrees C, the 28 day value is 1.3 moles per mole of tricalcium silicate. Combining these results with previous measurements of the free water index made using quasielastic neutron scattering reveals that the hydrogen content of the C-S-H gel decreases significantly at increased curing temperature. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Illinois, Dept Geol, Urbana, IL 61801 USA. Fed Highway Adm, Exploratory Res Team, Mclean, VA 22101 USA. RP FitzGerald, SA (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 19 TC 27 Z9 27 U1 4 U2 11 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 1999 VL 14 IS 3 BP 1160 EP 1165 DI 10.1557/JMR.1999.0154 PG 6 WC Materials Science, Multidisciplinary SC Materials Science GA 235PB UT WOS:000082550300069 ER PT J AU Lugez, CL Lovas, FJ Hougen, JT Ohashi, N AF Lugez, CL Lovas, FJ Hougen, JT Ohashi, N TI Global analysis of a-, b-, and c-type transitions involving tunneling components of K=0 and 1 states of the methanol dimer SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID MICROWAVE-SPECTRUM; WATER DIMER; SPLITTINGS AB Spectral data on K = 0 and 1 levels of the methanol dimer available from previous and present Fourier transform microwave measurements have been interpreted globally, using a group-theoretically derived effective Hamiltonian and corresponding tunneling matrix elements to describe the splittings arising from a large number of tunneling motions. In the present work, 302 new measurements (40 K = 1-1 and 262 K = 1-0 transitions) were added to the previous data set to give a total of 584 assigned transitions with J less than or equal to 6. As a result of the rather complete K = 0, 1 data set for J less than or equal to 4, the lone-pair exchange tunneling splittings were obtained experimentally. Matrix element expansions in J(J + 1) used in the previous K = 0 formalism were modified to apply to K > 0, essentially by making a number of real coefficients complex, as required by the generalized internal-axis-method tunneling formalism. To reduce the number of adjustable parameters to an acceptable level in both the K = 0 and K = 1 effective Hamiltonians (used in separate K = 0 and K = 1 least-squares fits), a rather large number of assumptions concerning probably negligible parameters had to be made. The present fitting results should thus be considered as providing assurance of the group-theoretical line assignments as well as a nearly quantitative global interpretation of the tunneling splittings, even though they do not yet unambiguously determine the relative contributions from all 25 group-theoretically inequivalent tunneling motions in this complex, nor do they permit quantitative extrapolation to higher K levels. (C) 1999 Academic Press. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. Kanazawa Univ, Fac Sci, Dept Phys, Kanazawa, Ishikawa 9201192, Japan. RP Lugez, CL (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 7 TC 12 Z9 12 U1 1 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 MAR PY 1999 VL 194 IS 1 BP 95 EP 112 DI 10.1006/jmsp.1998.7767 PG 18 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 166NV UT WOS:000078584000012 ER PT J AU Li, ZG Harlow, RL Foris, CM Li, H Ma, P Vickery, RD Maurin, MB Toby, BH AF Li, ZG Harlow, RL Foris, CM Li, H Ma, P Vickery, RD Maurin, MB Toby, BH TI Polymorph determination for the GP IIb/IIIa antagonist, roxifiban, using a combination of electron diffraction and synchrotron X-ray powder diffraction techniques SO JOURNAL OF PHARMACEUTICAL SCIENCES LA English DT Article AB Unit cell parameters of two polymorphs of roxifiban have been determined by a combination of transmission electron microscopy (TEM) single-crystal and synchrotron X-ray powder diffraction techniques. While it was difficult to differentiate the two forms by their standard X-ray diffraction patterns, the high-resolution synchrotron patterns clearly showed striking differences. Unit cells for the two forms required the use of cell parameters derived from TEM diffraction patterns. The two unit cells are, not surprisingly, very similar except for a doubling of one of the axes for form II. The combined use of TEM and synchrotron patterns appears to be a good general approach for characterizing complex (low-symmetry, large unit cell) polymorphs. C1 Dupont Co, Sci & Engn Lab, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. Dupont Merck Pharmaceut Co, Chem Proc R&D, Deepwater, NJ 08023 USA. Dupont Merck Pharmaceut Co, Pharm R&D, Wilmington, DE 19880 USA. Natl Inst Stand & Technol, Ctr Neutron Res E151 235, Gaithersburg, MD 20899 USA. RP Li, ZG (reprint author), Dupont Co, Sci & Engn Lab, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. RI Toby, Brian/F-3176-2013 OI Toby, Brian/0000-0001-8793-8285 NR 6 TC 10 Z9 12 U1 0 U2 1 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0022-3549 J9 J PHARM SCI JI J. Pharm. Sci. PD MAR PY 1999 VL 88 IS 3 BP 297 EP 301 DI 10.1021/js9803306 PG 5 WC Chemistry, Medicinal; Chemistry, Multidisciplinary; Pharmacology & Pharmacy SC Pharmacology & Pharmacy; Chemistry GA 173CW UT WOS:000078964500003 PM 10052986 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 CA IUPAC Subcommittee Gas Kinetic Data Evaluation TI Evaluated kinetic and photochemical data for atmospheric chemistry, organic species: Supplement VII 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 GAS-PHASE REACTIONS; OH RADICAL REACTIONS; ABSORPTION CROSS-SECTIONS; PHOTOLYSIS-RESONANCE FLUORESCENCE; LASER FLASH-PHOTOLYSIS; TEMPERATURE-DEPENDENT KINETICS; JANAF THERMOCHEMICAL TABLES; HYDROGEN-ATOM ABSTRACTION; ABSOLUTE RATE CONSTANTS; RELATIVE RATE CONSTANTS 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); 1.8, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997)], The present evaluation is limited to the organic 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 171 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 which 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) 1999 American Institute of Physics and American Chemical Society. [S0047-2689(94)00102-6]. C1 Univ Calif Riverside, Air Pollut Res Ctr, Riverside, CA 92521 USA. Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 USA. Univ Calif Riverside, 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. NIST, Chem Kinet Data Ctr, Gaithersburg, MD 20899 USA. Univ Birmingham, Sch Chem, Birmingham B15 2TT, W Midlands, England. Ecole Polytech Fed Lausanne, Lab Pollut Atmospher & Sol, LPAS, IGR, CH-1015 Lausanne, Switzerland. Univ Gottingen, Inst Phys Chem, D-37077 Gottingen, Germany. RP Atkinson, R (reprint author), Univ Calif Riverside, Air Pollut Res Ctr, Riverside, CA 92521 USA. RI ROSSI, Michel J./C-7878-2013 OI ROSSI, Michel J./0000-0003-3504-695X NR 682 TC 271 Z9 275 U1 9 U2 68 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 1999 VL 28 IS 2 BP 191 EP 393 DI 10.1063/1.556048 PG 203 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 229DX UT WOS:000082179200001 ER PT J AU Armstrong, RA AF Armstrong, RA TI Stable model structures for representing biogeochemical diversity and size spectra in plankton communities SO JOURNAL OF PLANKTON RESEARCH LA English DT Article ID TEMPORAL VARIABILITY; GRAPHICAL APPROACH; ECOSYSTEM MODEL; NUTRIENT-UPTAKE; MIXED-LAYER; FOOD WEBS; OCEAN; PHYTOPLANKTON; DYNAMICS; PRODUCTIVITY AB There is a fundamental duality in the way we view planktonic communities. On one hand, we see these communities as composed of a diverse mixture of taxonomically and biogeochemically distinct species; pelagic ecosystem models capable of predicting the ocean's role in the global carbon cycle will need to resolve these multiple plankton taxa. However, we have also come to appreciate that superimposed on this diversity are regular patterns of size structure, where plots of abundance within size classes typically show a power-law dependence on size. A truly complete model description of planktonic community structure must reflect both aspects of this duality. Here I examine two classes of ecosystem models that are capable of representing this duality. The first structure is based on multiple (n) couplets of phytoplankton (P) and zooplankton (Z) [an 'n(PZ)' model]. Within certain regions of parameter space, this model structure can produce anomalous oscillatory behaviors, the mathematical origin of which is explored in detail. I then examine an alternative food web structure in which total herbivore abundance is represented by a single state variable, G, and where grazing pressure is distributed among taxa in proportion to their abundances. This '(nP)G' system is stabilized by the redistribution of grazing intensity among taxa in response to changes in their densities. This 'distributed grazing' model also naturally produces size spectra of plankton abundance; this last observation argues that the model with distributed grazing can help in uncovering and representing the mechanistic basis for the genesis and maintenance of planktonic size spectra of phytoplankton and bacteria. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Armstrong, RA (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, Sayre Hall,POB CN710, Princeton, NJ 08544 USA. RI Armstrong, Robert/C-9086-2009 NR 45 TC 53 Z9 53 U1 1 U2 8 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0142-7873 J9 J PLANKTON RES JI J. Plankton Res. PD MAR PY 1999 VL 21 IS 3 BP 445 EP 464 DI 10.1093/plankt/21.3.445 PG 20 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 177KJ UT WOS:000079208900003 ER PT J AU Gartz, RG Miller, LW Fujimura, RW Smith, PE AF Gartz, RG Miller, LW Fujimura, RW Smith, PE TI Measurement of larval striped bass (Morone saxatilis) net avoidance using evasion radius estimation to improve estimates of abundance and mortality SO JOURNAL OF PLANKTON RESEARCH LA English DT Article ID ENGRAULIS-MORDAX; ANCHOVY AB Net avoidance rate increases as a function of larval striped bass size. This causes underestimation of abundance and overestimation of mortality rate. We modeled net avoidance by assuming that fish avoid the net by swimming a radial distance at a right angle to the net axis. This distance, the evasion radius, was estimated by comparing the calculated densities of striped bass larvae from a series of paired tows involving a large and a small net. Iteration and solution models were used to estimate the evasion radius for each millimeter size group of fish in order to estimate the actual density in the environment. Avoidance of the nets increased with fish length. The ratio of actual density in the environment to the measured density in the small net was used to adjust abundances measured in our ichthyoplankton surveys. After adjusting for net avoidance, mortality rates of striped bass larvae from the Sacrament-San Joaquin Estuary were reduced by 10% compared to the unadjusted rates. C1 Calif Dept Fish & Game, Cent Valley & Bay Delta Branch, Stockton, CA 95205 USA. NOAA, NMFS, SW Fisheries Ctr, La Jolla, CA 92038 USA. RP Gartz, RG (reprint author), Calif Dept Fish & Game, Cent Valley & Bay Delta Branch, 4001 N Wilson Way, Stockton, CA 95205 USA. NR 17 TC 3 Z9 3 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0142-7873 J9 J PLANKTON RES JI J. Plankton Res. PD MAR PY 1999 VL 21 IS 3 BP 561 EP 580 DI 10.1093/plankt/21.3.561 PG 20 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 177KJ UT WOS:000079208900009 ER PT J AU Kato, S Ackerman, TP Dutton, EG Laulainen, N Larson, N AF Kato, S Ackerman, TP Dutton, EG Laulainen, N Larson, N TI A comparison of modeled and measured surface shortwave irradiance for a molecular atmosphere SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article ID PLANETARY-ATMOSPHERES; MULTIPLE-SCATTERING; RADIATIVE-TRANSFER; APPROXIMATION; FLUXES; LIGHT AB We compare the downward diffuse and direct normal irradiance computed by a two-stream model with measurements taken at the Mauna Loa Observatory when the atmosphere was close to a molecular atmosphere. The modeled downward diffuse irradiance agrees with measurements taken by a shaded pyranometer within the uncertainty of the measurement. Therefore, the two-stream approximation is adequate for computing the downward diffuse irradiance in a molecular atmosphere. This result also indicates that neglecting the state of polarization introduces a negligible error in the irradiance computation. Published by Elsevier Science Ltd. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Kato, S (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 33 TC 15 Z9 17 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAR PY 1999 VL 61 IS 4 BP 493 EP 502 DI 10.1016/S0022-4073(98)00032-6 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 164AR UT WOS:000078440200007 ER PT J AU Park, K Zink, LR Chance, KV Evenson, KM Nolt, IG AF Park, K Zink, LR Chance, KV Evenson, KM Nolt, IG TI Pressure broadening of the 118.455 cm(-1) rotational lines of OH by N-2, O-2, H-2, and He SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article AB We measured the pressure broadening of the 118.455cm(-1) (3.551Thz) rotational lines of OH by H-2, He, N-2 and O-2 From these measurements, we calculated the pressure broadening of this line by air. The broadening coefficients are 6.06(16) and 10.13(25) x 10(-7) cm(-1) Pa-1 at 296 and 194 K. We also measured the position of the manifold of lines, with results that are in excellent agreement with a previous accurate determination. The frequency of the strongest component of the transition (F = 4 <-- 3), and its 2 sigma uncertainty is 3551185.32(3) MHz. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Oregon, Dept Phys, Eugene, OR 97403 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Park, K (reprint author), Univ Oregon, Dept Phys, Eugene, OR 97403 USA. OI Chance, Kelly/0000-0002-7339-7577 NR 6 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAR PY 1999 VL 61 IS 5 BP 715 EP 716 DI 10.1016/S0022-4073(98)00057-0 PG 2 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 163UE UT WOS:000078424100016 ER PT J AU Burns, DT Lamperti, P O'Brien, M AF Burns, DT Lamperti, P O'Brien, M TI Comparison of the NIST and BIPM air-kerma standards for measurements in the low-energy x-ray range SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE air kerma; free-air ionization chamber; primary standard; reference radiation qualities AB A direct comparison was made between the air-kerma standards used for the measurement of low-energy x rays at the National Institute of Standards and Technology (NIST) and the Bureau International des Poids et Mesures (BIPM). The comparison was carried out at the BIPM using the BIPM reference beam qualities in the range from 10 kV to 100 kV. The results show the standards to be in agreement to around 0.5 % at reference beam qualities up to 50 kV and at 100 kV. The result at the 80 kV beam quality is less favorable, with agreement at the 1 % level. C1 Bur Int Poids & Mesures, F-92312 Sevres, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Burns, DT (reprint author), Bur Int Poids & Mesures, F-92312 Sevres, France. NR 7 TC 3 Z9 3 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 MAR-APR PY 1999 VL 104 IS 2 BP 135 EP 140 DI 10.6028/jres.104.009 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000001 ER PT J AU Ellerbe, P Phinney, CS Sniegoski, LT Welch, MJ AF Ellerbe, P Phinney, CS Sniegoski, LT Welch, MJ TI Validation of new instrumentation for isotope dilution mass spectrometric determination of organic serum analytes SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE definitive methods; isotope dilution mass spectrometry; measurement ID CANDIDATE DEFINITIVE METHOD AB A major activity in the 20 year collaboration between the Analytical Chemistry Division at NIST and the College of American Pathologists (CAP) has been the development of highly accurate and precise "definitive" methods for important clinical analytes in human serum. Definitive methods for organic analytes use isotope dilution/gas chromatography/mass spectrometry and require a mass spectrometer capable of making highly precise measurements of the ratio between the ion intensities of a characteristic ion from the analyte of interest and its stable-isotope-labeled analog. Recently the mass spectrometer used for 20 years for definitive method development and measurements was replaced with a modern instrument capable of automated operation, with accompanying gains in convenience and sample throughput. Switching to the new instrument required modifications of measurement protocols, acceptance criteria, and ratio calculations with background corrections to go along with automated instrument operation. Results demonstrated that the two instruments gave comparable results for measurements of both urea and cholesterol in samples from various serum-based Standard Reference Materials [SRMs] and College of American Pathologists materials. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Ellerbe, P (reprint author), Coll Amer Pathologists, Northfield, IL 60093 USA. NR 10 TC 1 Z9 1 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 MAR-APR PY 1999 VL 104 IS 2 BP 141 EP 145 DI 10.6028/jres.104.010 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000002 ER PT J AU Kaduk, JA Wong-Ng, W Greenwood, W Dillingham, J Toby, BH AF Kaduk, JA Wong-Ng, W Greenwood, W Dillingham, J Toby, BH TI Crystal structures and reference powder patterns of BaR2ZnO5 (R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, and Tm) SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE BaR2ZnO5(R = lanthanides); crystal structure; x-ray and neutron Rietveld refinements; x-ray reference powder patterns ID OXIDES; DIFFRACTION; SUPERCONDUCTOR; ZINC AB Reference x-ray powder patterns and the crystal structures of the lanthanide compounds, BaR2ZnO5, in which R = La, Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm, were determined by the x-ray Rietveld refinement technique. A structural trend was confirmed for this series of compounds. The compounds with smaller ionic radii (R = Sm, Eu, Gd, Dy, Ho, Y, Er, or Tm) are isostructural to the orthorhombic "green phase" (BaY2CuO5). The lattice parameters for compounds with R = Tm to Sm range from a = 7.01855(9) Angstrom to 7.20452(14) Angstrom, b = 12.25445 (17) Angstrom to 12.5882(2) Angstrom, and c = 5.6786(14) Angstrom to 5.81218(11) Angstrom, respectively. R is sevenfold coordinated inside a monocapped trigonal prism. These prisms share edges to form wave-like chains parallel to the long b-axis. The BaR2ZnO5 compounds which contain larger size R (La and Nd) crystallize in the tetragonal space group 14/mcm. The lattice parameters are a = 6.90982(10) and c = 11.5977(2) Angstrom for BaLa2ZnO5, and a = 6.75979(5) Angstrom and c = 11.54560(12) Angstrom for BaNd(2)ZnO5. The structure consists of ZnO4 tetrahedra (instead of planar CuO4 groups as found in BaR2CuO5) with 10-fold coordinated bicapped square prismatic Ba and 8-fold coordinated bicapped trigonal prismatic R ions between them. The reference x-ray powder patterns will be submitted to the Powder Diffraction File (PDF). C1 Amoco Corp, Naperville, IL 60566 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. RP Kaduk, JA (reprint author), Amoco Corp, Naperville, IL 60566 USA. RI Toby, Brian/F-3176-2013 OI Toby, Brian/0000-0001-8793-8285 NR 22 TC 36 Z9 38 U1 0 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 1999 VL 104 IS 2 BP 147 EP 171 DI 10.6028/jres.104.011 PG 25 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000003 ER PT J AU Dickens, B Dickens, SH AF Dickens, B Dickens, SH TI Estimation of concentration and bonding environment of water dissolved in common solvents using near infrared absorptivity SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE analysis; determination of water in solvents; hydrogen bonding distribution; near infrared spectroscopy AB Integrated near infrared (NIR) absorbance has been used to determine the absorptivity of the upsilon(2) + upsilon(3) combination band of the asymmetric stretch (upsilon(2)) and the bending vibration (upsilon(3)) for water in several organic solvents. Absorptivity measured in this way is essentially constant across the absorption envelope and is found to be 336 L mol(-1) cm(-1) with a standard deviation of 4 L mol(-1) cm(-1) as estimated from a least squares fit of a straight line to data from water concentrations between 0.01 mol/L and 0.06 mol/L. Absorptivity measured from the peak maximum of the upsilon(2) + upsilon(3) combination band of water varies with the type of hydrogen bonding of the water molecule because the shape of the NIR absorption envelope changes with the hydrogen bonding. Because the integrated NIR absorptivity of the upsilon(2) + upsilon(3) combination band of water is essentially constant across the absorption envelope, the NIR absorption envelope reflects the distribution of hydrogen bonding of the water. The shape and location of the absorption envelope appear to be governed mostly by the number of hydrogen bonds from the water molecules to easily polarized atoms. Water that is a donor in hydrogen bonds to atoms which are not easily polarized (such as the oxygen of a typical carbonyl group) absorbs near 5240 cm(-1) to 5260 cm(-1). Water that donates one hydrogen bond to an easily polarized atom (such as a water molecule oxygen) absorbs near 5130 cm(-1) to 5175 cm(-1), and water that donates two hydrogen bonds to easily polarized atoms is estimated to absorb near 5000 cm(-1) to 5020 cm(-1). Water donating two hydrogen bonds to other water molecules may be said to be in a water-like environment. In no case does a small amount of water absorbed in a host material appear to have a water-like environment. C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Dickens, B (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. NR 5 TC 26 Z9 26 U1 0 U2 4 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 1999 VL 104 IS 2 BP 173 EP 183 DI 10.6028/jres.104.012 PG 11 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000004 ER PT J AU Nadal, ME Barnes, PY AF Nadal, ME Barnes, PY TI Near infrared 45 degrees/0 degrees reflectance factor of pressed polytetrafluoroethylene (PTFE) powder SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE bidirectional reflectance distribution function (BRDF); diffuse reflectance; 45 degrees/0 degrees reflectance factor; pressed polytetrafluoroethylene (PTFE) powder AB Pressed polytetrafluoroethylene (PTFE) powder is commonly used as a reflectance standard for bidirectional and hemispherical geometries. The wavelength dependence of the reflectance factor of PTFE is presented for the near-infrared spectral region (800 nm to 1600 nm) for the 45 degrees/0 degrees geometry, as well as in the visible spectral region (380 Nm to 800 nm) for comparison with previously published results. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Nadal, ME (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 7 TC 6 Z9 6 U1 2 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 1999 VL 104 IS 2 BP 185 EP 188 DI 10.6028/jres.104.013 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000005 ER PT J AU Mopsik, FI AF Mopsik, FI TI A fast method of transforming relaxation functions into the frequency domain SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE cubic spline; error estimate; Laplace transform; numeric integration; numeric transform; relaxation function; time domain AB The limits to the error due to truncation of the numeric integration of the one-sided Laplace transform of a relaxation function in the time domain into its equivalent frequency domain are established. Separate results are given for large and small omega. These results show that, for a given omega, only a restricted range of time samples is needed to perform the computation to a given accuracy. These results are then combined with a known error estimate for integration by cubic splines to give a good estimate for the number of points needed to perform the computation to a given accuracy. For a given data window between t(1) and t(2), the computation time is shown to be proportional to In(t(1)/t(2)). C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mopsik, FI (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 5 TC 3 Z9 3 U1 1 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 1999 VL 104 IS 2 BP 189 EP 192 DI 10.6028/jres.104.014 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000006 ER PT J AU Flater, D AF Flater, D TI Manufacturer's CORBA Interface Testing Toolkit: Overview SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE code generation; CORBA; software; testing AB The Manufacturer's CORBA Interface Testing Toolkit (MCITT) is a software package that supports testing of CORBA components and interfaces. It simplifies the testing of complex distributed systems by producing "dummy components" from Interface Testing Language and Component Interaction Specifications and by automating some error-prone programming tasks. It also provides special commands to support conformance, performance, and stress testing. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 9 TC 1 Z9 1 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 MAR-APR PY 1999 VL 104 IS 2 BP 193 EP 200 DI 10.6028/jres.104.015 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 204JW UT WOS:000080762000007 ER PT J AU Vanderah, TA Wong-Ng, W Toby, BH Browning, VM Shull, RD Geyer, RG Roth, RS AF Vanderah, TA Wong-Ng, W Toby, BH Browning, VM Shull, RD Geyer, RG Roth, RS TI Characterization of ternary compounds in the BaO : Fe2O3 : TiO2 system: Ba6Fe45Ti17O106 and BaFe11Ti3O23 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID CRYSTAL-STRUCTURE; DIFFRACTION; CHEMISTRY; FERRITE; SOLIDS; OXIDES AB Single crystals of Ba6Fe45Ti17O106 and BaFe11Ti3O23 were obtained as major and minor coproducts, respectively, by slow-cooling an off-stoichiometric BaO:Fe2O3:TiO2 melt. The former compound exhibits variable stoichiometry, Ba6Fe48-xTi14+xO106, with the Fe:Ti ratio dependent upon the partial pressure of oxygen. The value of x corresponds to the equivalents of reduction that occur to maintain electroneutrality as the Ti-content increases. When prepared in air, this phase occurs at x = 3 with the stoichiometry Ba6Fe45Ti17O106, while in 100% oxygen the x-value approaches zero with the resulting stoichiometry Ba6Fe48Ti14O106 (all Fe3+ and Ti4+). The structures of Ba6Fe45Ti17O106 and BaFe11Ti3O23 were solved using single-crystal X-ray diffraction methods. Ba6Fe45Ti17O106 was prepared in polycrystalline form, and further structural details, including accurate Fe/Ti occupancy factors, were determined by a combined refinement using neutron and synchrotron powder diffraction data. (Ba6Fe45Ti17O106: Space group C2/m (No. 12); 19.390(1) Angstrom, b = 20.260(1) Angstrom, c = 10.076(1) Angstrom, beta= 105.27(1)degrees; V = 3818.5(3) Angstrom(3); Z = 2; rho(calc) = 5.08 g/cm(3). Ba6Fe11 Ti3O23: Space group C2/c (No. 15); a = 19.561(1) Angstrom, b= 8.6614(7) A, c = 10.120(1) Angstrom, beta = 105.62(1)degrees; V = 1651.1(3) Angstrom(3); Z = 4; rho(calc)=5.08g/cm(3).) Both compounds adopt eight-layer close-packed structures built from alternating ccp and hcp [O,(Ba, O)] layers stacked along the a-direction with a (ch)(4) repeat sequence. Both structures feature octahedral sites occupied by a mixture of Fe and Ti as well as tetrahedral sites occupied by Fe3+; the structural formulas are (Ba6 Fe6)-Ba-XII-Fe-IV (VI)(Fe39Ti17)O-106 and Ba-XII Fe-IV(2) (VI)(Fe9Ti3)O-23. Both compounds are partially reduced; the former contains 3 moles of Fe2+ (or Ti3+) per formula unit, and the latter contains 1 mole. The formation of Fe2+ is considered more likely than Ti3+, but could not be experimentally confirmed. BaFe11Ti3O23 is apparently metastable in air when cooled from above the solidus and could not be prepared as a polycrystalline sample. Indexed experimental Xray powder diffraction data for Ba6Fe45Ti17O106 are given. Polycrystalline samples of this compound were used to measure its magnetic and electrical properties. The magnetic behavior of Ba6Fe45Ti17O106 above room temperature up to 1073K was found to obey the Curie-Weiss law, which indicated a small effective magnetic moment (34 mu(B) per mole Ba6Fe45Ti17O106) and a large negative temperature intercept (- 806 K). Electrical resistivity measurements between room temperature and 120 K revealed nonmetallic behavior with an activation energy on the order of 0.17eV. At 347 MWz under ambient conditions, Ba6Fe45Ti17O106 exhibited a relative permittivity of 24 and a dielectric loss tangent of 0.10. (C) 1999 Academic Press. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Elect & Elect Engn Lab, Boulder, CO 80303 USA. USN, Res Lab, Washington, DC 20375 USA. RP Vanderah, TA (reprint author), NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RI Toby, Brian/F-3176-2013; Shull, Robert/F-5971-2013 OI Toby, Brian/0000-0001-8793-8285; NR 42 TC 9 Z9 9 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 EI 1095-726X J9 J SOLID STATE CHEM JI J. Solid State Chem. PD MAR PY 1999 VL 143 IS 2 BP 182 EP 197 DI 10.1006/jssc.1999.8075 PG 16 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 182MK UT WOS:000079502600005 ER PT J AU Page, SH Benner, BA Small, JA Choquette, SJ AF Page, SH Benner, BA Small, JA Choquette, SJ TI Restrictor plugging in off-line supercritical fluid extraction of environmental samples - Microscopic, chemical, and spectroscopic evaluations SO JOURNAL OF SUPERCRITICAL FLUIDS LA English DT Article DE restrictor plugging; standard reference material; supercritical fluid extraction ID CHROMATOGRAPHY MASS-SPECTROMETRY; CAPILLARY GAS-CHROMATOGRAPHY; CARBON-DIOXIDE; ANALYTE COLLECTION; SFE; PRODUCTS; SOILS; OIL; FRACTIONATION; RECOVERY AB Irreversible restrictor plugging is often a problem in supercritical fluid extraction (SFE) with linear restrictors. Restrictor plugging occurs when high temperature (200 degrees C) off-line SFE is performed on either the marine sediment (SRM 1941) or the urban dust (SRM 1649) standard reference material (SRM). Microscopic evaluation of the linear restrictors (50 mu m i.d. x 40 cm long fused silica capillary) showed that a solid mass approximately 1 cm to 3 cm from the tip of the restrictor caused the plugging in the case of SRM 1941. Three distinct zones of analyte deposition were observed in the restrictor used during SFE of SRM 1649 - a thin, diffuse, granular him (3 cm to 13 cm from tip), a thick, wavy film (13 cm to 17 cm from tip), and plugs of highly viscous liquid (17 cm to 28 cm from tip). Raman microscopy and X-ray microanalysis confirmed that inorganic sulfur was the major component of the material plugging the restrictor when SRM 1941 was extracted. X-ray microanalysis and direct insertion probe mass spectrometry confirmed that dichlorophen, phthalate esters, hydrocarbon fragments, and other compounds were contained in the material plugging the restrictor when SRM 1649 was extracted. In both cases the plugging did not occur at the tip of the restrictor. Both isenthalpic and isentropic explanations for plugging in SRM 1649 and 1941 are invalid because the zones of plugging are significantly removed from the tip of the restrictor and decompression occurred over a large region of the restrictor. The analytes appeared to have condensed in the linear restrictor either immediately after exiting the oven (SRM 1649) or further down the restrictor (SRM 1941). (C) 1999 Elsevier Science B.V. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Benner, BA (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 53 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0896-8446 J9 J SUPERCRIT FLUID JI J. Supercrit. Fluids PD MAR 1 PY 1999 VL 14 IS 3 BP 257 EP 270 DI 10.1016/S0896-8446(98)00124-7 PG 14 WC Chemistry, Physical; Engineering, Chemical SC Chemistry; Engineering GA 158UW UT WOS:000078136600009 ER PT J AU McCowan, CN Wang, CM Vigliotti, DP AF McCowan, CN Wang, CM Vigliotti, DP TI Charpy impact verification data (1994-1996): A summary SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE Charpy V-notch; impact certification program; impact testing; notched-bar testing; pendulum impact machines; reference specimens AB We present a summary of Charpy impact verification test data that were evaluated by the National Institute of Standards and Technology from January 1994 to December 1996. The Charpy impact machines that met the verification requirements of ASTM Test Methods for Notched Bar Impact Testing of Metallic Materials (E 23) are broken down by year and by reference lot. Based on the data, a proposed verification rule that limits the range of the verification set has been examined. We also present the results for determining whether two energies (lower and upper ends of the machine capacity) or three (lower, middle, and upper) are needed to verify the performance of the large-capacity impact machines; currently E 23 requires three energies to be tested. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Stat Engn Div, Boulder, CO 80303 USA. RP McCowan, CN (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, 325 Broadway, Boulder, CO 80303 USA. NR 6 TC 1 Z9 1 U1 0 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAR PY 1999 VL 27 IS 2 BP 89 EP 99 PG 11 WC Materials Science, Characterization & Testing SC Materials Science GA 287YN UT WOS:000085535200002 ER PT J AU Slotwinski, JA Blessing, GV AF Slotwinski, JA Blessing, GV TI Ultrasonic measurement of the dynamic elastic moduli of small metal samples SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE elastic moduli; nondestructive evaluation; Poisson's ratio; ultrasonics; Young's modulus AB Ultrasonic velocity measurements were used to determine the dynamic elastic moduli of small metal samples to a 2 sigma measurement uncertainty of better than 1%. The samples were cylindrical in shape, possessing nominal diameters of 12 mm and thicknesses of 6 mm. Aluminum, titanium, and stainless steel compositions were examined, In the longitudinal wave measurements, a 20-MHz quartz piezoelectric element transducer was employed in pulse-echo mode using a tone-burst excitation. These longitudinal time-of-flight measurements were made with a repeatable 2 sigma measurement uncertainty of less than or equal to 1.0 ns. Shear time-of-flight measurements, using a 10-h MHz contact ceramic piezoelectric element transducer subjected to tone-burst excitation. were made with a repeatable 2 sigma measurement uncertainty of approximate to 2.0 ns. NIST calibration facilities provided measurements for the density and lengths of these samples. as needed for the moduli calculations. Results indicate that the measurement uncertainties for elastic moduli measurements of this type can be kept quite small. C1 Natl Inst Stand & Technol, Automated Prod Technol Div, Mfg Engn Lab, Gaithersburg, MD 20899 USA. RP Slotwinski, JA (reprint author), Natl Inst Stand & Technol, Automated Prod Technol Div, Mfg Engn Lab, Gaithersburg, MD 20899 USA. NR 8 TC 4 Z9 4 U1 1 U2 3 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD MAR PY 1999 VL 27 IS 2 BP 164 EP 166 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA 287YN UT WOS:000085535200012 ER PT J AU Shang, EC Wang, YY AF Shang, EC Wang, YY TI Subarctic frontal effects on long-range acoustic propagation in the North Pacific Ocean SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID SIMULATION AB Acoustic propagation along the Hawaiian-Aleutian path at low frequency (65 Hz) for the acoustic thermometry of ocean climate (ATOC) has been simulated using the implicit finite difference parabolic equation (IFD-PE). This simulation is based upon the Semtner-Chervin model with one-half-degree resolution. The adiabaticity has been assessed, and it was found that Significant mode coupling takes place at the sub-arctic front area (44.8 degrees N). Due to the range-dependent double channel, two characteristic ranges were identified in this area: (i) the modal degeneration range R-m(D) and (ii) the modal scattering range R-m(S). At range R-m(D), mode m and mode n (usually, It = m + 1) are degenerated, the modal wave numbers of mode m and mode n become equal, and mode n then takes the shape of mode m. Therefore, there is no real repopulation (modal Scattering), but a modal name change takes place at this range. The modal name change can cause a miscalculation of the adiabatic R-m(S),, however, real repopulation does take place. Numerical simulations travel time. At range R-m(S) illustrate that R-m(D) and R-m(S) are separated by about 10 km at lower modes (m < 5) and are merged at higher modes. (C) 1999 Acoustical Society of America. [S0001-4966(99)06603-5]. C1 Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Shang, EC (reprint author), Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NR 8 TC 4 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAR PY 1999 VL 105 IS 3 BP 1592 EP 1595 DI 10.1121/1.426699 PG 4 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 175DW UT WOS:000079078500017 ER PT J AU Lewis, CW Stevens, RK Rasmussen, RA Cardelino, CA Pierce, TE AF Lewis, CW Stevens, RK Rasmussen, RA Cardelino, CA Pierce, TE TI Biogenic fraction of ambient VOC: Comparison of radiocarbon, chromatographic, and emissions inventory estimates for Atlanta, Georgia SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID VOLATILE ORGANIC-COMPOUNDS; SAMPLES; URBAN AB Previously reported volatile organic compounds (VOC) radiocarbon (C-14) measurements for 1992 summertime Atlanta, GA, have been compared with chromatographic data and emissions inventory predictions. The chromatographic approach that was used provided a more comprehensive VOC characterization than typically achieved, and the emissions inventory was research-grade level (date-, site-, and time-specific). The comparisons are-in general agreement that biogenic emissions contribute only modestly (<10%) to the VOC content of the particular ambient samples that were collected and measured. The choices of sampling site (near city-center) and times (early morning and late evening) are major influences on the results, which consequently should not be regarded as representing the average VOC biogenic impact for the Atlanta area. C1 US EPA, NERL, Res Triangle Pk, NC 27711 USA. Florida Dept Environm Protect, Tallahassee, FL USA. Oregon Grad Inst Sci & Technol, Portland, OR USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NOAA, Air Resources Lab, Res Triangle Pk, NC USA. RP Lewis, CW (reprint author), US EPA, NERL, MD-47, Res Triangle Pk, NC 27711 USA. EM lewis.charlesw@epamail.epa.gov NR 20 TC 7 Z9 7 U1 0 U2 1 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 MAR PY 1999 VL 49 IS 3 BP 299 EP 307 PG 9 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 174WJ UT WOS:000079059100006 PM 28060594 ER PT J AU Wallace, WE Guttman, CM Antonucci, JM AF Wallace, WE Guttman, CM Antonucci, JM TI Molecular structure of silsesquioxanes determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID SYNTHETIC PLATFORMS; SILOXANE COPOLYMERS; POLYMERS; MONOMERS AB Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to deduce the three-dimensional structure of a complex silsesquioxane polymer. Four distinct: levels of structure were observed in the mass spectrum. The overall shape of the peak distribution was typical of polymers formed by condensation reactions. The mass separation between major clusters of peaks, each major cluster corresponding to an oligomer with a unique number of repeat units, confirmed that the synthesis proceeded as expected with no side reactions: The mass separation between peaks within a major cluster showed that intramolecular reactions during synthesis resulted in the elimination of water. The loss of water was ascribed to the formation of closed loops in the polymer structure. A simple arithmetic algorithm is presented for identifying these peaks. Autocorrelation techniques were used to determine the number and distribution of intramolecular closed loops per oligomer. This knowledge was used to deduce whether a particular oligomer is branched-linear, ladder, polyhedral, or some combination of these. The single-oligomer isotopic distribution was used to determine that cationization was present from both sodium and potassium ions. (C) 1999 American Society for Mass Spectrometry. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Wallace, WE (reprint author), NIST, Div Polymers, Bldg 224,Room B320, Gaithersburg, MD 20899 USA. EM william.wallace@nist.gov NR 21 TC 60 Z9 62 U1 0 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD MAR PY 1999 VL 10 IS 3 BP 224 EP 230 DI 10.1016/S1044-0305(98)00147-0 PG 7 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 170LL UT WOS:000078807100004 ER PT J AU Bellows, RJ Lin, MY Arif, M Thompson, AK Jacobson, D AF Bellows, RJ Lin, MY Arif, M Thompson, AK Jacobson, D TI Neutron imaging technique for in situ measurement of water transport gradients within Nafion in polymer electrolyte fuel cells SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID MEMBRANES; MODEL AB Water transport is an important consideration in the optimization of polymer electrolyte fuel cell (PEFC) performance, affecting both internal resistance and cathode polarization losses. Novel experiments are described using neutron radiography to measure water gradient profiles within Nafion(R) in an operating PEFC. Preliminary neutron intensity gradients show qualitative agreement with the expected response of membrane water content to changes in feed gas humidification and fuel cell current. Previous experimental measurements of similar water gradients have generally relied on "integral" measurements such as ac impedance spectroscopy which cannot probe details of the gradient within the membrane. This is one of the first "differential" measurements of water gradients within Nafion. (C) 1999 The Electrochemical Society. S0013-4651(98)10-004-6. All rights reserved. C1 Exxon Res & Engn Co, Annandale, NJ 08801 USA. NIST, Gaithersburg, MD 20899 USA. RP Bellows, RJ (reprint author), Exxon Res & Engn Co, Route 22 E, Annandale, NJ 08801 USA. NR 19 TC 222 Z9 225 U1 0 U2 15 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 MAR PY 1999 VL 146 IS 3 BP 1099 EP 1103 DI 10.1149/1.1391727 PG 5 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 178XG UT WOS:000079294000042 ER PT J AU Chen, F Mitchell, K AF Chen, F Mitchell, K TI Using the GEWEX/ISLSCP forcing data to simulate global soil moisture fields and hydrological cycle for 1987-1988 SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID LAND-SURFACE; ETA-MODEL; FIFE DATA; PARAMETERIZATION; PRECIPITATION; SENSITIVITY; TEMPERATURE; REANALYSIS; IMPACT; BUDGET AB The GEWEX/ISLSCP Global Soil Wetness Project is an international initiative to enlist a spectrum of land-surface modeling centers and programs to use common global atmospheric forcing data sets to drive their respective land-surface models, in order to simulate and compare global soil wetness fields, and ultimately apply them in GCM sensitivity tests, as a participant in this project, we used the common ISLSCP atmospheric forcing data for 1987-1988 and our NCEP land-surface model (LSM) to generate global hydrological fields, including soil moisture, which cannot be obtained uniformly over large continental areas from scattered observations. We found that the simulated global hydrological cycle reasonably reflects the seasonal variation of those hydrological fields. Despite the relatively coarse 1 x 1 degree resolution of forcing data, the soil moisture field has a remarkable spatial variability, which is related not only to the spatial pattern of precipitation, but also to the spatial distribution of runoff and evaporation. Also, the spatial variability in vegetation and soil characteristic contributes to the variability in the surface hydrological cycle. We also compared our simulated global land-surface hydrological cycle to the 1987-1988 NCEP/NCAR reanalysis of land-surface products. It seems that, in most regions, the reanalysis of soil moisture has a larger annual cycle amplitude than the GSWP soil moisture. A more remarkable difference is that in the mid- and high-latitudes of the northern hemisphere, the reanalysis has a more uniformly distributed and wetter soil moisture than the corresponding GSWP soil moisture, which reflected the artificial climatological soil moisture damping field applied in the reanalysis system. Finally, we attempted to validate our soil moisture simulations with soil moisture measured by the Illinois Soil Moisture Network, and focused on the comparison of the area-averaged deep root zone soil moisture. It appears that the simulated soil moisture of 1987-1988 in the state of Illinois is able to reasonably capture not only the phase of the seasonal evolution, but also the amplitude of annual variation. The encouraging results indicate that a sound LSM can well simulate the natural soil moisture evolution, given accurate atmospheric forcing and reasonable specification of local vegetation and soil characteristics. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NCEP, NWS, NOAA, Environm Modeling Ctr, Camp Springs, MD USA. RP Chen, F (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM feichen@ncar.ucar.edu RI Chen, Fei/B-1747-2009 NR 34 TC 31 Z9 38 U1 0 U2 3 PU METEOROLOGICAL SOC JAPAN PI TOKYO PA C/O JAPAN METEOROLOGICAL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, 100-0004, JAPAN SN 0026-1165 EI 2186-9057 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD MAR PY 1999 VL 77 IS 1B BP 167 EP 182 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232DU UT WOS:000082351300002 ER PT J AU Steffens, KL Sobolewski, MA AF Steffens, KL Sobolewski, MA TI Planar laser-induced fluorescence of CF2 in O-2/CF4 and O-2/C2F6 chamber-cleaning plasmas: Spatial uniformity and comparison to electrical measurements SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article ID INFRARED-ABSORPTION SPECTROSCOPY; CONFERENCE REFERENCE CELL; KRF LASER; 248 NM; RADIOFREQUENCY DISCHARGES; PHOTOPHYSICS; RADICALS; MECHANISMS; SYSTEM; MODEL AB Planar laser-induced fluorescence (PLIF) measurements were made to determine two-dimensional spatial maps of CF2 density as an indicator of chemical uniformity in 92% CF4/O-2 and 50% C2F6/O-2 chamber-cleaning plasmas at pressures between 13.3 Pa (100 mTorr) and 133.3 Pa (1000 mTorr). Measurements were also made of broadband optical emission and of discharge current, voltage and power. All measurements were made in a Gaseous Electronics Conference Reference Cell, a capacitively coupled, parallel-plate platform designed to facilitate comparison of results among laboratories. The CF2 PLIF and emission results were found to correlate with discharge current and voltage measurements. Together, these optical and electrical measurements provide insight into the optimization of chamber-cleaning processes and reactors, suggest new methods of monitoring plasma uniformity, and identify important spatial effects which should be included in computer simulations. [S0734-2101(99)02602-0]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Steffens, KL (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 36 TC 22 Z9 22 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD MAR-APR PY 1999 VL 17 IS 2 BP 517 EP 527 DI 10.1116/1.581613 PG 11 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 177GX UT WOS:000079203200027 ER PT J AU Kang, HJ Zhao, Q Talke, FE Perettie, DJ Dekoven, BM Morgan, TA Fischer, DA Hsu, SM Bhatia, S AF Kang, HJ Zhao, Q Talke, FE Perettie, DJ Dekoven, BM Morgan, TA Fischer, DA Hsu, SM Bhatia, S TI The use of cyclic phosphazene additives to enhance the performance of the head/disk interface (c) SO LUBRICATION ENGINEERING LA English DT Article DE phase separation; phosphazine additives; start/stop and drag testing; near edge X-ray absorption fine structure ID HARD DISKS; DEGRADATION AB Phase separation of phosphazene additives in PFPAE lubricants is investigated as a function of additive concentration and lubricant-layer thickness. The tribological behavior of various phosphazene additive/lubricant mixtures is evaluated using start/stop and constant-speed dr-ag testing. Near edge X-ray absorption fine structure (NEXAFS) is applied to investigate the presence of unsaturated carbon bonds at interfaces lubricated with Z-DOLG(C) and Z-DOL/additives mixtures. C1 Univ Calif San Diego, Ctr Magnet Recording Res, La Jolla, CA 92093 USA. Dow Chem Co, Midland, MI 48674 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20879 USA. IBM Corp, SSD, San Jose, CA 95193 USA. RP Kang, HJ (reprint author), Dankook Univ, Dept Polymer Sci & Engn, Seoul 140714, South Korea. NR 10 TC 7 Z9 7 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD MAR PY 1999 VL 55 IS 3 BP 22 EP 27 PG 6 WC Engineering, Mechanical SC Engineering GA 177AX UT WOS:000079186100006 ER PT J AU Clapham, PJ Young, SB Brownell, RL AF Clapham, PJ Young, SB Brownell, RL TI Baleen whales: conservation issues and the status of the most endangered populations SO MAMMAL REVIEW LA English DT Review DE baleen whales; Right Whale; Bowhead Whale; Gray Whale; Blue Whale; Humpback Whale; conservation ID SOUTHERN RIGHT WHALES; NORTH-ATLANTIC; BALAENA-MYSTICETUS; HUMPBACK WHALES; MEGAPTERA-NOVAEANGLIAE; EUBALAENA-GLACIALIS; BOWHEAD WHALE; GRAY WHALES; ABUNDANCE; ORGANOCHLORINE AB Most species of baleen whales were subject to intensive overexploitation by commercial whaling in this and previous centuries, and many populations were reduced to small fractions of their original sizes. Here, we review the status of baleen whale stocks, with an emphasis on those that are known or thought to be critically endangered. Current data suggest that, of the various threats potentially affecting baleen whales, only entanglement in fishing gear and ship strikes may be significant at the population level, and then only in those populations which are already at critically low abundance. The impact of some problems (vessel harassment, and commercial or aboriginal whaling) is at present probably minor. For others (contaminants, habitat degradation, disease), existing data either indicate no immediate cause for concern, or are insufficient to permit an assessment. While the prospect for many baleen whales appears good, there are notable exceptions; populations that are of greatest concern are those suffering from low abundance and associated problems, including (in some cases) anthropogenic mortality. These include: all Northern Right Whales Eubalaena glacialis, Bowhead Whales Balaena mysticetus of the Okhotsk Sea and various eastern Arctic populations, western Gray Whales Eschrichtius robustus, and probably many Blue Whale Balaenoptera musculus populations. We review the status of these populations and, where known, the issues potentially affecting their recovery. Although Humpback Whales Megaptera novaeangliae and Southern Right Whales Eubalaena australis were also heavily exploited by whaling, existing data indicate strong recovery in most studied populations of these species. C1 NE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Woods Hole, MA 02540 USA. Humane Soc United States, Bourne, MA 02532 USA. SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, La Jolla, CA 92038 USA. RP Clapham, PJ (reprint author), NE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 166 Water St, Woods Hole, MA 02540 USA. NR 178 TC 113 Z9 129 U1 18 U2 140 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0305-1838 J9 MAMMAL REV JI Mammal Rev. PD MAR PY 1999 VL 29 IS 1 BP 35 EP 60 PG 26 WC Zoology SC Zoology GA 190AU UT WOS:000079940000002 ER PT J AU Carlson, HR Pfister, CA AF Carlson, HR Pfister, CA TI A seventeen-year study of the rose star Crossaster papposus population in a coastal bay in southeast Alaska SO MARINE BIOLOGY LA English DT Article ID LIFE-HISTORIES; INTERTIDAL COMMUNITY; DYNAMICS; RECRUITMENT; DISTURBANCE; SUCCESSION; DEMOGRAPHY; MORTALITY; PATTERNS; GROWTH AB A 17 yr study of a population of the rose star Crossaster papposus (Linnaeus, 1767) in Auke Bay, near Juneau, Alaska, used SCUBA to follow a total of 956 individually marked stars. Population density was relatively constant over the 17 yr of study, although the influx of smaller individuals varied by an order of magnitude. Growth in diameter of individual stars was inversely related to size, with the largest individuals showing negligible growth for periods of months or years. Annual survivorship was relatively high (from 76.3 to 90.4%), and some individuals persisted throughout the study, indicating longevities of at least 20 yr in this species. Observations of food habits indicated that the principal prey item is the reddish scallop Chlamys rubida. In summary, this rose star population was characterized by a relatively stable number of long-lived, slow-growing individuals. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. Univ Chicago, Dept Ecol & Evolut, Chicago, IL 60637 USA. RP Carlson, HR (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 52 TC 8 Z9 8 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD MAR PY 1999 VL 133 IS 2 BP 223 EP 230 DI 10.1007/s002270050461 PG 8 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 178ML UT WOS:000079269700006 ER PT J AU Thurston, SW AF Thurston, SW TI The Asian-Pacific Economic Cooperation (APEC) Oceans Conference - "Realizing the opportunities for APEC economies" - Commentary SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Editorial Material C1 NOAA, Japan Marine Sci & Technol Ctr, Off Global Programs, Yokosuka, Kanagawa, Japan. RP Thurston, SW (reprint author), NOAA, Japan Marine Sci & Technol Ctr, Off Global Programs, Yokosuka, Kanagawa, Japan. NR 0 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI COLUMBIA PA 5565 STERRETT PLACE, STE 108, COLUMBIA, MD 21044 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SPR PY 1999 VL 33 IS 1 BP 85 EP 87 PG 3 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 199JL UT WOS:000080477400011 ER PT J AU Spencer, PL Janish, PR Doswell, CA AF Spencer, PL Janish, PR Doswell, CA TI A four-dimensional objective analysis scheme and multitriangle technique for wind profiler data SO MONTHLY WEATHER REVIEW LA English DT Article ID DIVERGENCE; NETWORK; DIAGNOSIS; FIELDS; SYSTEM AB A 4D Barnes objective analysis scheme for wind profiler data is developed in order to improve upon previously developed 2D analysis schemes. A significant shortcoming of the 2D schemes is their sensitivity to gaps in the profiler time-height series; they may produce unrealistic gradient information if large data-void regions are present. The 4D analysis scheme described herein, however, provides an effective means for dealing with data voids within profiler time-height series. The 4D analysis scheme differs from the 2D techniques in that data from neighboring profiler stations affect the time-height wind analysis at each site. This allows the analysis scheme to produce smooth, spatially and temporally consistent time-height wind analyses for each station of the Wind Profiler Network (WPN), even if large data gaps are present. Gridded time-height wind fields at each profiler site resulting from the 4D analysis scheme are provided as input to a line integral-equivalent technique that is applied over many WPN triangles for the purpose of diagnosing the kinematic and thermodynamic structure of subsynoptic-scale weather systems. Time-height series of triangle derived variables have been proven elsewhere to be an effective method for diagnosing subsynoptic-scale temporal structure of weather systems; mapping the irregularly spaced triangle information onto a regular, quasihorizontal grid provides a complementary perspective of their spatial structure and evolution. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. NOAA, Natl Ctr Environm Predict, Storm Predict Ctr, Norman, OK USA. RP Spencer, PL (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. RI Doswell III, Charles/E-7662-2010 NR 29 TC 4 Z9 4 U1 0 U2 0 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 MAR PY 1999 VL 127 IS 3 BP 279 EP 291 DI 10.1175/1520-0493(1999)127<0279:AFDOAS>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 171NH UT WOS:000078869700002 ER PT J AU Munitz, A Livne, Z Rawers, JC Adams, JS Fields, RJ AF Munitz, A Livne, Z Rawers, JC Adams, JS Fields, RJ TI Effect of nitrogen on the mechanical properties and microstructure of hot isostatically pressed nanograined Fe SO NANOSTRUCTURED MATERIALS LA English DT Article ID ALLOYS; COMPACTION; POWDERS AB The effect of nitrogen content in Fe powders on the mechanical properties and microstructure of cold isostatic pressed (CIPed) and sintered or hot isostatic pressed (HIPed) Fr powders which was produced by attrition ball milling was investigated. Microhardness and compression tests were used to determine the mechanical properties. Optical. scanning, and transmission electron microscopy were used to investigate the microstructural changes that occurred Juring consolidation. Sintering of the CIPed bodies at temperatures below 850 degrees C caused no change in density, with only minor mechanical properties improvement. and the bodies remained friable. HIPing was found to be essential for effective consolidation of ball-milled powders. Increasing HIPing temperatures increased the density, the compression yield stress, the maximum compressive strength, and the hardness to a maximum value and then decreased. The maximum in density preceded the maximum in the compression yield stress, and its value depends on the nitrogen content in the powder. At low HIPing temperatures (<580 degrees C) the nitrogen content has no influence on the mechanical properties. However, above 580 degrees C, the nitrogen content reduces the mechanical properties as well as density. and increases the oxide precipitation. There are two microstructural effects of nitrogen on the microstructure: void formation in the Fr bodies HIPed above 580 degrees C for the higher nitrogen concentrations, and severe grain boundary embrittlement above 965 degrees C. Iron bodies processed in argon have smaller grain size than iron bodies processed in nitrogen throughout the entire consolidation temperature range. However, due to the smaller grain size, the optimum in mechanical properties (maximum strength with reasonable elongation) is reached only above 965 degrees C. Processing in argon improves machinability. (C) 1999 Acta Metallurgica Inc. C1 Nucl Res Ctr Negev, IL-84190 Beer Sheva, Israel. US DOE, Albany, OR 97321 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Munitz, A (reprint author), Nucl Res Ctr Negev, POB 9001, IL-84190 Beer Sheva, Israel. NR 16 TC 10 Z9 11 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD MAR PY 1999 VL 11 IS 2 BP 159 EP 177 DI 10.1016/S0965-9773(99)00029-X PG 19 WC Materials Science, Multidisciplinary SC Materials Science GA 211QP UT WOS:000081172200002 ER PT J AU Calleja, M Anguita, J Garcia, R Birkelund, K Perez-Murano, F Dagata, JA AF Calleja, M Anguita, J Garcia, R Birkelund, K Perez-Murano, F Dagata, JA TI Nanometre-scale oxidation of silicon surfaces by dynamic force microscopy: reproducibility, kinetics and nanofabrication SO NANOTECHNOLOGY LA English DT Article ID SI(100) SURFACES; TRANSISTORS AB Local oxidation of silicon surfaces by scanning probe microscopy is a very promising lithographic approach at nanometre scale. Here, we present two approaches to optimize the oxidation for nanofabrication purposes: (i) we analyse the reproducibility and kinetics of the oxidation of Si(100) surfaces when there is no tip and sample mechanical contact and (ii) we study the effect of modulating the, voltage in the aspect ratio of the oxide structures grown. The finite tip-sample separation has remarkable practical consequences: the same tip can be used to perform thousands of modifications without any sign of wear. In addition, the structures generated do not show any degradation over long periods (months). It is also found that the kinetics is independent of the force microscopy mode used (contact or non-contact). On the other hand, the application of an AC voltage to induce the oxidation significantly modifies the aspect ratio of the structures. A detailed description of the oxidation mechanism is proposed to account for both results. C1 CSIC, Inst Microelect Madrid, Madrid 28760, Spain. Univ Autonoma Barcelona, Dept Elect Engn, Bellaterra 08193, Spain. NIST, Gaithersburg, MD 20899 USA. RP Calleja, M (reprint author), CSIC, Inst Microelect Madrid, Isaac Newton 8, Madrid 28760, Spain. RI Garcia, Ricardo/B-3124-2013; Perez-Murano, Francesc/A-6384-2013; Microelectronica de Madrid, Instituto de/D-5173-2013; calleja, montserrat/B-7857-2014 OI Garcia, Ricardo/0000-0002-7115-1928; Perez-Murano, Francesc/0000-0002-4647-8558; Microelectronica de Madrid, Instituto de/0000-0003-4211-9045; calleja, montserrat/0000-0003-2414-5725 NR 14 TC 43 Z9 45 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0957-4484 J9 NANOTECHNOLOGY JI Nanotechnology PD MAR PY 1999 VL 10 IS 1 BP 34 EP 38 DI 10.1088/0957-4484/10/1/008 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Science & Technology - Other Topics; Materials Science; Physics GA 182YH UT WOS:000079525400008 ER PT J AU Suzuki, M Saxena, SK Boix, E Prill, RJ Vasandani, VM Ladner, JE Sung, C Youle, RJ AF Suzuki, M Saxena, SK Boix, E Prill, RJ Vasandani, VM Ladner, JE Sung, C Youle, RJ TI Engineering receptor-mediated cytotoxicity into human ribonucleases by steric blockade of inhibitor interaction SO NATURE BIOTECHNOLOGY LA English DT Article DE ribonuclease inhibitor; eosinophil-derived neurotoxin; site-directed mutagenesis; receptor-mediated endocytosis; immunotoxin ID EOSINOPHIL-DERIVED NEUROTOXIN; HUMAN PLACENTAL RIBONUCLEASE; BOVINE SEMINAL RIBONUCLEASE; TRANSFERRIN RECEPTOR; CATIONIC PROTEIN; SOLID TUMORS; MECHANISM; INVITRO; RNASE; ANGIOGENIN AB Several nonmammalian members of the RNase A superfamily exhibit anticancer activity that appears to correlate with resistance to the cytosolic ribonuclease inhibitor (RI). We mutated two human ribonucleases-pancreatic RNase (hRNAse) and eosinophil-derived neurotoxin (EDN)-to incorporate cysteine residues at putative sites of close contact to RI, but distant from the catalytic sites. Coupling of Cys89 of RNase and Cys87 of EDN to proteins at these sites via a thioether bond produced enzymatically active conjugates that were resistant to RI. To elicit cellular targeting as well as to block RI binding, transferrin was conjugated to a mutant human RNase, rhRNase(Gly89--->Cys) and a mutant EDN (Thr87-->Cys). The transferrin-rhRNase(Gly89-->Cys) thioether conjugate was 5000-fold more toxic to U251 cells than recombinant wild-type hRNase. In addition, transferrin-targeted EDN exhibited tumor cell toxicities similar to those of hRNase, Thus, we endowed two human RI-sensitive RNases with greater cytotoxicity by increasing their resistance to RI. This strategy has the potential to generate a novel set of recombinant human proteins useful for targeted therapy of cancer. C1 NINCDS, Biochem Sect, Surg Neurol Branch, NIH, Bethesda, MD 20892 USA. Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. NIH, Drug Delivery & Kinet Resource Bioengn & Phys Sci, Off Res Serv, Bethesda, MD 20892 USA. RP Youle, RJ (reprint author), NINCDS, Biochem Sect, Surg Neurol Branch, NIH, Bethesda, MD 20892 USA. RI Boix, Ester/B-9038-2012; OI Boix, Ester/0000-0003-1790-2142; Saxena, Shailendra K/0000-0003-2856-4185 NR 31 TC 62 Z9 64 U1 0 U2 6 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1087-0156 J9 NAT BIOTECHNOL JI Nat. Biotechnol. PD MAR PY 1999 VL 17 IS 3 BP 265 EP 270 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 173JM UT WOS:000078977500028 PM 10096294 ER PT J AU Geiger, SB Gurbatov, D Dariel, MP Eichmiller, FC Liberman, R Ratzker, M AF Geiger, SB Gurbatov, D Dariel, MP Eichmiller, FC Liberman, R Ratzker, M TI Surface treatment of mercury-free alloys SO OPERATIVE DENTISTRY LA English DT Article AB Finishing and polishing methods were examined for two metallic direct restorative materials being proposed as possible alternatives to amalgam, namely a gallium alloy and it consolidated silver alloy. The polished surfaces were compared to a conventional spherical amalgam (Tytin). After initial surface treatment with a 12-fluted tungsten carbide bur in a high-speed dental handpiece, three polishing methods were evaluated: slow-speed polishing burs, rubber polishing points, and polishing disks (Sof-Lex). Each of these methods was followed by an additional surface treatment in which a pumice-flour/water slurry was applied with a rotary brush and a final surface treatment with a zinc-oxide/ethanol slurry that was applied with rotary rubber cups. The surface roughness was evaluated by profilometric measurements and light microscopy. The results showed that the smoothest surfaces for all metals were achieved with rotary finishing and polishing disks. Using the rubber points resulted in surfaces that were statistically similar to the disk-polished surfaces on all three materials. The polished surface of gallium alloy was consistently slightly rougher than that of amalgam. The consolidated silver also presented a consistently rougher surface than did amalgam, although these differences were not statistically significant. The additional polishing with pumice and zinc oxide improved the luster, but did not significantly improve the measured surface smoothness in any of the restorative materials studied. C1 NIST, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Geiger, SB (reprint author), Tel Aviv Univ, Sch Dent Med, Tel Aviv, Israel. NR 6 TC 1 Z9 1 U1 0 U2 0 PU UNIV WASHINGTON PI SEATTLE PA SCHOOL DENTISTRY SM-57, SEATTLE, WA 98195 USA SN 0361-7734 J9 OPER DENT JI Oper. Dent. PD MAR-APR PY 1999 VL 24 IS 2 BP 103 EP 108 PG 6 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 173FA UT WOS:000078969500007 PM 10483447 ER PT J AU Orzel, C Walhout, M Sterr, U Julienne, PS Rolston, SL AF Orzel, C Walhout, M Sterr, U Julienne, PS Rolston, SL TI Spin polarization and quantum-statistical effects in ultracold ionizing collisions SO PHYSICAL REVIEW A LA English DT Article ID METASTABLE XENON; TRAPPED ATOMS; GAS; CONDENSATION; HELIUM; SHIFT AB We have measured ultracold ionizing collision rates for three bosonic (Xe-132, Xe-134, and Xe-136) and two fermionic (Xe-129 and Xe-131) isotopes of xenon in the 6s[3/2](2) metastable state, for both spin-polarized and unpolarized samples. For unpolarized samples at temperatures above the p-wave centrifugal barrier (similar to 39 mu K). we find that collision rates for all isotopes are identical. Quantum-statistical effects forbid s-wave collisions for spin-polarized fermions, giving rise to significant differences between bosonic and fermionic isotopes below the p-wave barrier. We present a technique for measuring collision rates at temperatures below 1 mu K, and find that the ratio of polarized to unpolarized collision rates for fermions decreases by a factor of 2 at low temperatures, while the ratio for bosons increases by 50%. We find no evidence of an overall reduction in the collision rate for spin-polarized samples, as has been observed in metastable helium. These results are explained using a simple theoretical model of transmission and quantum reflection off long-range interatomic potentials. [S1050-2947(99)02802-4]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Chem Phys Program, College Pk, MD 20742 USA. Calvin Coll, Dept Phys, Grand Rapids, MI 49546 USA. Phys Tech Bundesanstalt, D-38116 Braunschweig, Germany. RP Orzel, C (reprint author), Natl Inst Stand & Technol, PHY A167, Gaithersburg, MD 20899 USA. RI rolston, steven/L-5175-2013; Julienne, Paul/E-9378-2012 OI rolston, steven/0000-0003-1671-4190; Julienne, Paul/0000-0002-5494-1442 NR 27 TC 29 Z9 30 U1 1 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1999 VL 59 IS 3 BP 1926 EP 1935 DI 10.1103/PhysRevA.59.1926 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 177WC UT WOS:000079233200034 ER PT J AU Tseng, CH Enzer, D Gabrielse, G Walls, FL AF Tseng, CH Enzer, D Gabrielse, G Walls, FL TI 1-bit memory using one electron: Parametric oscillations in a Penning trap SO PHYSICAL REVIEW A LA English DT Article ID CYCLOTRON MOTION; MICROWAVE CAVITY; SINGLE ELECTRON; SHIFTS AB The parametric oscillation of a single trapped electron is studied and used to measure enhanced spontaneous emission. Hysteresis in this motion provides a 1-bit memory to store information about excitations made with the electron "in the dark." The time dependence and stability criteria for the parametric excitation are examined. The cyclotron motions for one and two electrons are also studied. [S1050-2947(99)01303-7]. C1 Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Tseng, CH (reprint author), MIT, Dept Nucl Engn, 150 Albany St, Cambridge, MA 02139 USA. NR 25 TC 13 Z9 13 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1999 VL 59 IS 3 BP 2094 EP 2104 DI 10.1103/PhysRevA.59.2094 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 177WC UT WOS:000079233200052 ER PT J AU Schneider, BI Feder, DL AF Schneider, BI Feder, DL TI Numerical approach to the ground and excited states of a Bose-Einstein condensed gas confined in a completely anisotropic trap SO PHYSICAL REVIEW A LA English DT Article ID DEPENDENT SCHRODINGER-EQUATION; CRITICAL-TEMPERATURE; COLLECTIVE EXCITATIONS; QUANTUM-MECHANICS; DYNAMICS; INTERFERENCE; ATOMS; THERMODYNAMICS; APPROXIMATION; PROPAGATION AB The ground and excited states of a weakly interacting and dilute Bose-Einstein condensed gas, confined in a completely anisotropic harmonic oscillator potential, are determined at zero temperature within the Bogoliubov approximation. The numerical calculations employ a computationally efficient procedure based on a discrete variable representation (DVR) of the Hamiltonian. The DVR is efficient for problems where the interaction potential may be expressed as a local function of interparticle coordinates. In order to address condensates that are both very large (similar to 10(6) atoms) and fully anisotropic, the ground state is found using a self-consistent held approach. Experience has demonstrated, however, that standard iterative techniques applied to the solution of the nonlinear partial differential equation for the condensate are nonconvergent. This limitation is overcome using the method of direct inversion in the iterated subspace (DIIS). In addition, the sparse structure of the DVR enables die efficient application of iterative techniques such as the Davidson and/or Lanczos methods, to extract the eigenvalues of physical interest. The results are compared with recent experimental data obtained for Bose-Einstein condensed alkali-metal vapors confined in magnetic traps. [S1050-2947(99)05803-5]. C1 Natl Sci Fdn, Div Phys, Arlington, VA 22230 USA. Univ Oxford, Oxford OX1 3PU, England. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Schneider, BI (reprint author), Natl Sci Fdn, Div Phys, 4201 Wilson Blvd, Arlington, VA 22230 USA. NR 80 TC 66 Z9 66 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 1999 VL 59 IS 3 BP 2232 EP 2242 DI 10.1103/PhysRevA.59.2232 PG 11 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 177WC UT WOS:000079233200069 ER PT J AU Anderson, WR Bradley, CC McClelland, JJ Celotta, RJ AF Anderson, WR Bradley, CC McClelland, JJ Celotta, RJ TI Minimizing feature width in atom optically fabricated chromium nanostructures SO PHYSICAL REVIEW A LA English DT Article ID DEPOSITION; LIGHT; LITHOGRAPHY; MODELS; GROWTH; LENS AB We present a study of factors that influence the feature width of nanostructures formed by atom-optical direct-write lithography. In this process, chromium atoms travel through a standing-wave laser light field and are deposited on a surface. Due to the alum-light interaction, the atoms are focused onto the surface in the standing wave nodes, producing a pattern of parallel chromium lines with widths as small as 28 nm and a spatial period of 212.78 nm. We present calculations and measurements of feature widths representing an exploration of the effects of laser power and laser-substrate separation. Strong qualitative agreement is seen between calculations and the measurements, but the observed feature widths are uniformly larger than theoretical predictions. Experiments in which the total amount of chromium deposited is varied indicate that this difference can be attributed to chromium growth behavior. [S1050-2947(99)09503-7]. C1 Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP Anderson, WR (reprint author), Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. EM jabez@epg.nist.gov RI McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 NR 25 TC 71 Z9 82 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 MAR PY 1999 VL 59 IS 3 BP 2476 EP 2485 DI 10.1103/PhysRevA.59.2476 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 177WC UT WOS:000079233200092 ER PT J AU Burton, BP AF Burton, BP TI Empirical cluster expansion models of cation order-disorder in A(B '(1/3),B ''(2/3))O-3 perovskites SO PHYSICAL REVIEW B LA English DT Article ID PBMG1/3NB2/3O3 AB Minimal cluster expansion models of B-site cation ordering in A(B-1/3'B-2/3")O-3 perovskites are evaluated. It is demonstrated that the linear triplet interaction is both necessary and sufficient to stabilize the P (3) over bar m1 1:2 structure ground state that is observed in such compounds as Ba(Zn-1/3,Nb-2/3)O-3 and Ba(Zn-1/3,Ta-2/3)O-3. The linear triplet model exhibits a P (3) over bar m1-->Pm (3) over bar m transition at kT(C)/[- J((.-.-.))]=4.5184. The addition of a nearest-neighbor pair interaction permits the transition sequence P (3) over bar m1-->Fm (3) over bar m1:1 structure-->Pm (3) over bar m, which is observed in Ca(Ca-1/3,Nb-2/3)O-3, but not in a region of parameter space in which the lowest-energy ground state of the AB(x)'O-3-AB(1-x)"O-3 pseudobinary occurs at the A(B-1/3'B-2/3")O-3 composition. This latter condition can be satisfied by including a second many-body interaction, specifically, a cube minus the triangle of three second-neighbor pairs. Monte Carlo simulations with such a model generate microstructures of the type that are observed in Pb(Zn-1/3,Nb-2/3)O-3 and Pb(Mg-1/3,Nb-2/3)O-3. [S0163-1829(99)02509-6]. C1 Natl Inst Stand & Technol, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Burton, BP (reprint author), Natl Inst Stand & Technol, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 29 TC 29 Z9 31 U1 2 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1999 VL 59 IS 9 BP 6087 EP 6091 DI 10.1103/PhysRevB.59.6087 PG 5 WC Physics, Condensed Matter SC Physics GA 178EX UT WOS:000079254300024 ER PT J AU Kimura, H Hirota, K Matsushita, H Yamada, K Endoh, Y Lee, SH Majkrzak, CF Erwin, R Shirane, G Greven, M Lee, YS Kastner, MA Birgeneau, RJ AF Kimura, H Hirota, K Matsushita, H Yamada, K Endoh, Y Lee, SH Majkrzak, CF Erwin, R Shirane, G Greven, M Lee, YS Kastner, MA Birgeneau, RJ TI Neutron-scattering study of static antiferromagnetic correlations in La2-xSrxCu1-yZnyO4 SO PHYSICAL REVIEW B LA English DT Article ID DOPED LA2CUO4; SPIN-GLASS; SUPERCONDUCTIVITY; ORDER; LA2-XBAXCUO4; EXCITATIONS; PURE; SR AB Neutron-scattering measurements have been performed to search for possible elastic incommensurate magnetic peaks in superconducting La2-xSrxCuO4 with x=0.10, 0.12, and 0.15. The most dramatic effects are found for x=0.12; in this case, the peak intensity first appears at the onset of superconductivity T-c (=31 K). The resolution-limited peak width indicates that the static magnetic correlation length exceeds 200 Angstrom isotropically in the CuO2 planes. Weak elastic peaks are also observed at low temperatures for x=0.10 while for x = 0.15 any incommensurate elastic scattering is below the limit of detectability. Elastic peaks are observed in Zn-substituted nonsuperconducting La1.88Sr0.12Cu0.97Zn0.03O4 However, in this case, the Zn substitution degrades the magnetic order; the peak appears at lower temperature (17 K) and the correlation length is shorter (80 Angstrom) than that in the Zn-free x = 0.12 sample. [S0163-1829(99)02909-4]. C1 Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Yamada, K (reprint author), Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. RI Hirota, Kazuma/C-6797-2008; Yamada, Kazuyoshi/C-2728-2009 NR 28 TC 195 Z9 197 U1 1 U2 5 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1999 VL 59 IS 9 BP 6517 EP 6523 DI 10.1103/PhysRevB.59.6517 PG 7 WC Physics, Condensed Matter SC Physics GA 178EX UT WOS:000079254300070 ER PT J AU Ang, C Scott, JF Yu, Z Ledbetter, H Baptista, JL AF Ang, C Scott, JF Yu, Z Ledbetter, H Baptista, JL TI Dielectric and ultrasonic anomalies at 16, 37, and 65 K in SrTiO3 SO PHYSICAL REVIEW B LA English DT Article ID DOMAIN-WALL; PHASE; SR1-XCAXTIO3; TRANSITION AB In this paper we report coincident anomalies in both dielectric response acid sound velocities in strontium titanate around three temperatures 16, 37, and 65 K. The anomalies occur in both single-crystal specimens and ceramics, so they cannot be related to grain boundary mechanisms, but they are enhanced by bismuth doping. The results indicate that the dielectric and ultrasonic anomalies are dynamic and not static. The physical nature of the anomalies was briefly discussed. [S0163-1829(99)06109-3]. C1 Zhejiang Univ, Dept Phys, Hangzhou 310027, Peoples R China. Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Zhejiang Univ, Dept Mat Sci & Engn, Hangzhou 310027, Peoples R China. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. Univ Aveiro, Dept Ceram & Glass Engn, P-3810 Aveiro, Portugal. RP Ang, C (reprint author), Zhejiang Univ, Dept Phys, Hangzhou 310027, Peoples R China. NR 37 TC 74 Z9 74 U1 0 U2 12 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1999 VL 59 IS 10 BP 6661 EP 6664 DI 10.1103/PhysRevB.59.6661 PG 4 WC Physics, Condensed Matter SC Physics GA 177WG UT WOS:000079233600019 ER PT J AU Fong, HF Keimer, B Lynn, JW Hayashi, A Cava, RJ AF Fong, HF Keimer, B Lynn, JW Hayashi, A Cava, RJ TI Spin structure of the dopable quasi-one-dimensional copper oxide Ca2Y2Cu5O10 SO PHYSICAL REVIEW B LA English DT Article AB The x = 0 parent compound of the Ca2+xY2-xCu5O10 family of quasi-one-dimensional copper oxides was investigated by neutron powder diffraction. Long range antiferromagnetic order, with ferromagnetic alignment of the moments along the copper oxide chains, was observed below T-N = 29.5 K. The low temperature ordered moment is 0.92 mu(B), close to the free ion value. The results are compared to observations on other magnetically ordered copper oxides. [S0163-1829(99)09609-5]. C1 Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Natl Inst Stand & Technol, Reactor Div, Gaithersburg, MD 20899 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. RP Fong, HF (reprint author), Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. NR 14 TC 32 Z9 33 U1 2 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAR 1 PY 1999 VL 59 IS 10 BP 6873 EP 6876 DI 10.1103/PhysRevB.59.6873 PG 4 WC Physics, Condensed Matter SC Physics GA 177WG UT WOS:000079233600043 ER PT J AU Martys, NS Mountain, RD AF Martys, NS Mountain, RD TI Velocity Verlet algorithm for dissipative-particle-dynamics-based models of suspensions SO PHYSICAL REVIEW E LA English DT Article ID MOLECULAR-DYNAMICS; SIMULATION AB A velocity Verlet algorithm for velocity dependent forces is described for modeling a suspension of rigid body inclusions. The rigid body motion is determined from the quaternion-based scheme of Omelyan [Comput. Phys. 12, 97 (1998)]. An iterative method to determine angular velocity in a self-consistent fashion for this quaternion-based algorithm is presented. This method is tested for the case of liquid water. We also describe a method for evaluating the stress tensor for a system of rigid bodies that is consistent with the velocity Verlet alogorithm. Results are compared to the constraint-based rattle algorithm of Anderson [J. Comput. Phys. 52, 24 (1993)]. [S1063-651X(99) 13203-3]. C1 NIST, Bldg Mat Div, Gaithersburg, MD 20899 USA. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Martys, NS (reprint author), NIST, Bldg Mat Div, Gaithersburg, MD 20899 USA. EM nicos.martys@nist.gov; RMountain@nist.gov NR 16 TC 76 Z9 79 U1 2 U2 21 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD MAR PY 1999 VL 59 IS 3 BP 3733 EP 3736 DI 10.1103/PhysRevE.59.3733 PN B PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 177WF UT WOS:000079233500083 ER PT J AU Bonevich, J Josell, D AF Bonevich, J Josell, D TI Comment on "Dimensionally induced structural transformations in titanium-aluminum multilayers" SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Bonevich, J (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. NR 3 TC 4 Z9 4 U1 0 U2 4 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD MAR 1 PY 1999 VL 82 IS 9 BP 2002 EP 2002 DI 10.1103/PhysRevLett.82.2002 PG 1 WC Physics, Multidisciplinary SC Physics GA 171RC UT WOS:000078877000053 ER PT J AU Celotta, RJ Gadzuk, JW Powell, CJ AF Celotta, RJ Gadzuk, JW Powell, CJ TI Chris Ernie Earl Kuyatt - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Celotta, RJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD MAR PY 1999 VL 52 IS 3 BP 108 EP 108 DI 10.1063/1.882539 PG 1 WC Physics, Multidisciplinary SC Physics GA 173DC UT WOS:000078965100021 ER PT J AU Loezos, JM Vanderah, TA Drews, AR AF Loezos, JM Vanderah, TA Drews, AR TI Barium hollandite-type compounds BaxFe2xTi8-2xO16 with x = 1.143 and 1.333 SO POWDER DIFFRACTION LA English DT Article DE barium iron titanium oxides; hollandite; BaO : Fe2O3 : TiO2; incommensurate modulation; monoclinic to tetragonal phase transition; X-ray powder diffraction data ID STRUCTURAL-ANALYSIS; PHASE AB Experimental X-ray powder diffraction patterns and refined unit cell parameters for two barium hollandite-type compounds, BaxFe2xTi8-2xO16, with x=1.143 and 1.333, are reported here. Compared to the tetragonal parent structure, both compounds exhibit monoclinic distortions that increase with Ba content [Ba1.333Fe2.666Ti5.334O16: a=10.2328(8), b=2.9777(4), c=9.899(1) Angstrom, beta=91.04(1)degrees, V=301.58(5) Angstrom(3), Z=1, rho(calc)= 4.64 g/cc; Ba1.143Fe2.286Ti5.714O16: a=10.1066(6), b=2.9690(3), c=10.064(2) Angstrom, beta=90.077(6)degrees, V=301.98(4) Angstrom(3), 1=i, rho(calc)=4.48 g/cc]. The X-ray powder patterns for both phases contain a number of broad, weak superlattice peaks attributed to ordering of the Ba2+ ions within the tunnels of the hollandite framework structure. According to the criteria developed by Cheary and Squadrito [Acta Crystallogr. B 45, 205 (1989)], the observed positions of the (0k1)/(1k0) superlattice peaks are consistent with the nominal x-values of both compounds, and the k values calculated from the corresponding d-spacings suggest that the Ba ordering within the tunnels is commensurate for x = 1.333 and incommensurate for x = 1.143. High-temperature X-ray diffraction data indicate that the 1.333 compound undergoes a monoclinic-->tetragonal phase transition between 310 and 360 degrees C. (C) 1999 International Centre for Diffraction Data. [S0885-7156(98)00903-8]. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Ford Motor Co, Res Lab, Dearborn, MI 48121 USA. RP Loezos, JM (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 18 TC 12 Z9 12 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD MAR PY 1999 VL 14 IS 1 BP 31 EP 35 PG 5 WC Materials Science, Characterization & Testing SC Materials Science GA 174XP UT WOS:000079062000008 ER PT J AU Xu, HHK Giuseppetti, AA Eichmiller, FC Ives, LK AF Xu, HHK Giuseppetti, AA Eichmiller, FC Ives, LK TI Two-body sliding wear of a direct-filling silver alternative to amalgam SO QUINTESSENCE INTERNATIONAL LA English DT Article DE amalgam; silver alloy; two-body sliding wear; wear resistance ID POSTERIOR COMPOSITES; RESTORATIVE MATERIALS; CLINICAL WEAR; HUMAN ENAMEL; HARDNESS AB Objective: This study investigated the wear resistance of a mercury-free silver direct-filling material and a dental amalgam. Method and materials: A precipitated silver powder was rinsed with dilute fluoboric acid and consolidated into a cohesive solid. For tooth cavity restoration and flexural testing, the silver was consolidated with a dental amalgam plugger at a load of 15 N. For wear testing, because of the relatively large specimen size, the silver was pressed at a pressure of 150 MPa, yielding a density similar to that obtained by hand consolidation. Results: The silver had a flexural strength twice that of amalgam. Pin-on-disk wear resulted in a smooth surface and hardening in silver, as measured by indentation inside the wear tracks, in contrast to the damage that was found in amalgam, The wear track cross-sectional area (n = 12) at 10(6) revolutions was not statistically significantly different among amalgam, polished silver, and burnished silver. Conclusion: The consolidated silver exhibited work hardening and surface densification during wear and, as a result, was more resistant to wear-induced damage than amalgam. C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Xu, HHK (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Bldg 224,Room A-153, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [P 50 DE09322, IA 1Y01 DE30045] NR 36 TC 1 Z9 1 U1 0 U2 1 PU QUINTESSENCE PUBL CO INC PI CAROL STREAM PA 551 NORTH KIMBERLY DR, CAROL STREAM, IL 60188-1881 USA SN 0033-6572 J9 QUINTESSENCE INT JI Quintessence Int. PD MAR PY 1999 VL 30 IS 3 BP 199 EP 208 PG 10 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 177JD UT WOS:000079206100009 PM 10356574 ER PT J AU Gossard, EE Gutman, S Stankov, BB Wolfe, DE AF Gossard, EE Gutman, S Stankov, BB Wolfe, DE TI Profiles of radio refractive index and humidity derived from radar wind profilers and the Global Positioning System SO RADIO SCIENCE LA English DT Article ID CLEAR AIR AB It has often been pointed out that the Bragg backscatter of radar waves from elevated turbulent layers is very highly correlated with the height gradient of radio refractive index (RI) through these layers. However, many users need the profiles of RI, or the associated humidity, rather than profiles of their gradients. Simple integration of the gradients is usually not feasible because of ground or sea clutter and because biological scatterers such as insects and birds often severely contaminate the lower range gates. We show that if the total height-integrated RI is independently available (say, from the Global Positioning System (GPS)), and if the surface value of RI is known, the profiles of RI are retrievable with good accuracy. For those profiler systems equipped with a radio acoustic sounding system to measure temperature, the humidity is also retrievable. The method is demonstrated with data collected in southern California, where 7 hours of profiler data were recorded at 449 MHZ along with CPS data. Three radiosonde balloons were launched during the period, and the profiles of PI from the balloon and the profiler are compared. The advantages of the system are its invulnerability to nonprecipitating clouds (at frequencies of 449 MHZ or lower) and that it uses only facilities that will soon be deployed globally. Simulations are used to assess errors from various factors such as loss of sign of the gradient of the potential RI (important especially during some frontal events) and the presence of biological contaminants in some geographical areas (such as coastal zones and some agricultural areas at night). C1 Sci & Technol Corp, Environm Technol Lab, Boulder, CO 80303 USA. NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. RP Gossard, EE (reprint author), Sci & Technol Corp, Environm Technol Lab, R-E-ET4,325 Broadway, Boulder, CO 80303 USA. EM egossard@etl.noaa.gov; gutman@fsl.noaa.gov; bstankov@etl.noaa.gov; dwolfe@etl.noaa.gov NR 19 TC 14 Z9 16 U1 1 U2 4 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 MAR-APR PY 1999 VL 34 IS 2 BP 371 EP 383 DI 10.1029/1998RS900029 PG 13 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 180RQ UT WOS:000079399300007 ER PT J AU Wieman, CE Pritchard, DE Wineland, DJ AF Wieman, CE Pritchard, DE Wineland, DJ TI Atom cooling, trapping, and quantum manipulation SO REVIEWS OF MODERN PHYSICS LA English DT Article ID BOSE-EINSTEIN CONDENSATION; SODIUM ATOMS; HELIUM DIMER; INTERFEROMETER; TRANSITIONS; VAPOR; LIGHT; IONS AB Neutral atoms and ions can now be cooled, trapped, and precisely manipulated using laser beams and other electromagnetic fields. This has made it possible to control external degrees of freedom at the quantum level, thereby making possible a variety of interesting new physics. [S0034-6861(99)03802-7]. C1 Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RP Wieman, CE (reprint author), Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 55 TC 114 Z9 114 U1 1 U2 24 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0034-6861 J9 REV MOD PHYS JI Rev. Mod. Phys. PD MAR PY 1999 VL 71 IS 2 SI SI BP S253 EP S262 DI 10.1103/RevModPhys.71.S253 PG 10 WC Physics, Multidisciplinary SC Physics GA 172BE UT WOS:000078900800029 ER PT J AU Fu, J Tsai, V Konig, R Dixson, R Vorburger, T AF Fu, J Tsai, V Konig, R Dixson, R Vorburger, T TI Measurement error due to sample level misalignment on Si(111) single-atom step SO SCANNING LA English DT Article; Proceedings Paper CT Scanning 99 Conference CY APR 11-14, 1999 CL CHICAGO, ILLINOIS C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fu, J (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAR-APR PY 1999 VL 21 IS 2 BP 76 EP 76 PG 1 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 211QG UT WOS:000081171200030 ER PT J AU Thomson, RE Rice, P Roark, S Moreland, J AF Thomson, RE Rice, P Roark, S Moreland, J TI Effects of the lubrication layer on hard disk drives on chemically modified atomic force microscopy tips SO SCANNING LA English DT Article; Proceedings Paper CT Scanning 99 Conference CY APR 11-14, 1999 CL CHICAGO, ILLINOIS C1 Univ Colorado, NIST, Boulder, CO 80309 USA. RP Thomson, RE (reprint author), Univ Colorado, NIST, Boulder, CO 80309 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAR-APR PY 1999 VL 21 IS 2 BP 76 EP 77 PG 2 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 211QG UT WOS:000081171200031 ER PT J AU Wells, OC Postek, MT AF Wells, OC Postek, MT TI Detector strategy for the scanning electron microscope inspection and metrology of semiconductor wafers SO SCANNING LA English DT Article; Proceedings Paper CT Scanning 99 Conference CY APR 11-14, 1999 CL CHICAGO, ILLINOIS C1 IBM Corp, Div Res, Yorktown Heights, NY 10598 USA. NIST, Nanometer Scale Metrol Grp, Gaithersburg, MD 20899 USA. RP Wells, OC (reprint author), IBM Corp, Div Res, Yorktown Heights, NY 10598 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD MAR-APR PY 1999 VL 21 IS 2 BP 145 EP 146 PG 2 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 211QG UT WOS:000081171200116 ER PT J AU Derber, J Bouttier, F AF Derber, J Bouttier, F TI A reformulation of the background error covariance in the ECMWF global data assimilation system SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID STATISTICAL-INTERPOLATION AB The background error covariance plays an important role in modern data assimilation and analysis systems by determining the distribution of the information in the data in space and between variables. A new formulation has been developed for use in the ECMWF system. The non-separable structure functions depend on the horizontal and vertical scales and a generalized linear balance operator to imply multivariate structure functions. The balance operator is incorporated into the definition of the analysis variables to ensure good preconditioning of the problem. The formulation and structure of the background error covariance are presented, and the implications for the analysis increments are examined. This reformulation became the operational ECMWF formulation in 3D-Var in May 1997 and in 4D-Var in November 1997. C1 European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. NOAA, NCEP, Washington, DC 20233 USA. RP Bouttier, F (reprint author), European Ctr Medium Range Weather Forecasts, Shinfield Pk, Reading RG2 9AX, Berks, England. NR 12 TC 226 Z9 243 U1 1 U2 5 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 MAR PY 1999 VL 51 IS 2 BP 195 EP 221 DI 10.1034/j.1600-0870.1999.t01-2-00003.x PG 27 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 190TJ UT WOS:000079980700003 ER PT J AU Phillips, WD AF Phillips, WD TI Laser cooling and trapping of neutral atoms SO USPEKHI FIZICHESKIKH NAUK LA Russian DT Review ID RESONANCE-RADIATION PRESSURE; BOSE-EINSTEIN CONDENSATION; COLD CESIUM ATOMS; LAMB-DICKE LIMIT; SODIUM ATOMS; OPTICAL LATTICES; QUANTUM JUMPS; MAGNETIC TRAP; PHOTOASSOCIATIVE SPECTROSCOPY; ULTRACOLD COLLISIONS C1 Natl Inst Stand & Technol, Phys Lab, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Phillips, WD (reprint author), Natl Inst Stand & Technol, Phys Lab, Atom Phys Div, Gaithersburg, MD 20899 USA. NR 123 TC 8 Z9 8 U1 4 U2 17 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., 113095 MOSCOW, RUSSIA SN 0042-1294 J9 USP FIZ NAUK+ JI Uspekhi Fiz. Nauk PD MAR PY 1999 VL 169 IS 3 BP 305 EP 322 PG 18 WC Physics, Multidisciplinary SC Physics GA 193GW UT WOS:000080128400006 ER PT J AU Gormley, J Jach, T Steel, E Xiao, QF AF Gormley, J Jach, T Steel, E Xiao, QF TI Polycapillary x-ray optic spectral gain and transmission SO X-RAY SPECTROMETRY LA English DT Article ID FLUORESCENCE; RESOLUTION; FIBER AB Polycapillary x-ray optics are gaining increased attention as their transmission characteristics and manufacturing difficulties are better understood. This paper reports experimental results obtained with an optic that was designed for use with both Mo K alpha (17.5 keV) and Cu K alpha (8 keV), The spectral gain function from 4 to 30 keV was determined from measurements made with an Si(Li) detector, and the results were compared with Monte Carlo simulations. The spatial variation in the spectral transmission was examined with both an Si(Li) detector and a magnifying x-ray CCD camera. The results show that even though the individual capillaries are tapered, their performance is well described by a simple parabolic relationship between the radius of curvature and the maximum energy transmitted derived for capillaries of constant diameter. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 NIST, Gaithersburg, MD 20899 USA. Xray Opt Syst Inc, Albany, NY 12205 USA. RP Gormley, J (reprint author), Digirad, 7408 Trade St, San Diego, CA 92121 USA. NR 19 TC 10 Z9 10 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0049-8246 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD MAR-APR PY 1999 VL 28 IS 2 BP 115 EP 120 DI 10.1002/(SICI)1097-4539(199903/04)28:2<115::AID-XRS319>3.0.CO;2-N PG 6 WC Spectroscopy SC Spectroscopy GA 183XJ UT WOS:000079579200009 ER PT J AU Andronache, C Donner, LJ Seman, CJ Ramaswamy, V Hemler, RS AF Andronache, C Donner, LJ Seman, CJ Ramaswamy, V Hemler, RS TI Atmospheric sulfur and deep convective clouds in tropical Pacific: A model study SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CHEMICAL-SPECIES PRODUCTION; GENERAL-CIRCULATION MODEL; DROPLET EFFECTIVE RADIUS; ANTHROPOGENIC SULFATE; CONDENSATION NUCLEI; AEROSOL-PARTICLES; STRATOCUMULUS CLOUDS; RADIATIVE PROPERTIES; OPTICAL-PROPERTIES; STRATIFORM CLOUDS AB A high-resolution limited area nonhydrostatic model was used to simulate sulfate-cloud interactions during the convective activity in a case study from the Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment, December 20-25, 1992. The model includes a new detailed sulfate-cloud microphysics scheme designed to estimate the effects of sulfate on cloud microphysics and radiative properties and the effects of deep convection on the transport and redistribution of aerosol. The data for SO2 and SO4(2-) species were taken from the Pacific Exploratory Mission West B observations during February-March 1994. Results show that a change in sulfate loading from the minimum to the maximum observed value scenarios (i.e., from about 0.01 to 1 mu g m(-3)) causes a significant decrease of the effective radius of cloud droplets (changes up to 2 mu m on average) and an increase of the diagnostic number concentration of cloud droplets (typical changes about 5-20 cm(-3)). The change in the average net shortwave (SW) radiation flux above the clouds was estimated to be on average -1.5 W m(-2), with significant spatial and temporal variations, The horizontal average of the changes in the net SW radiation fluxes above clouds has a diurnal cycle, reaching typical values approximately -3 W m(-2). The changes in the average net longwave radiation flux above the clouds were negligible, but they showed significant variations, typically between -10 W m(-2) and 10 W m(-2) near the surface. These variations were associated mainly with the changes in the distribution of cloud water, which showed typical relative changes of cloud water path of about 10-20%. Other notable changes induced by the increase of aerosol were the variations in air temperature of the order of 1 degrees C. The case study presented here suggests that characteristics of convective clouds in tropical areas are sensitive to atmospheric sulfate loading, particularly during enhanced sulfate episodes. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Andronache, C (reprint author), Princeton Univ, Atmosher & Ocean Sci Program, Princeton, NJ 08544 USA. EM cna@gfdl.gov RI Andronache, Constantin/C-4431-2011 OI Andronache, Constantin/0000-0001-5375-7056 NR 76 TC 12 Z9 12 U1 0 U2 2 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 FEB 27 PY 1999 VL 104 IS D4 BP 4005 EP 4024 DI 10.1029/1998JD200085 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 169TF UT WOS:000078764100012 ER PT J AU Quinn, PK Coffman, DJ AF Quinn, PK Coffman, DJ TI Comment on "Contribution of different aerosol species to the global aerosol extinction optical thickness: Estimates from model results" by Tegen et al. SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material ID SEA-SALT; MARINE AEROSOL; METEOROLOGICAL TRANSPORT; MID-PACIFIC; CLOUDS; PARTICLES C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Ocean, 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 Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 23 TC 30 Z9 30 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 FEB 27 PY 1999 VL 104 IS D4 BP 4241 EP 4248 DI 10.1029/1998JD200066 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 169TF UT WOS:000078764100027 ER PT J AU Haywood, JM Ramaswamy, V Soden, BJ AF Haywood, JM Ramaswamy, V Soden, BJ TI Tropospheric aerosol climate forcing in clear-sky satellite observations over the oceans SO SCIENCE LA English DT Article ID SEA-SALT AEROSOLS; ANTHROPOGENIC SULFATE; ATMOSPHERIC AEROSOLS; RADIATION BUDGET; GREENHOUSE GASES; MODEL; SULFUR AB Tropospheric aerosols affect the radiative forcing of Earth's climate, but their variable concentrations complicate an understanding of their global influence. Model-based estimates of aerosol distributions helped reveal spatial patterns indicative of the presence of tropospheric aerosols in the satellite-observed clear-sky solar radiation budget over the world's oceans. The results show that, although geographical signatures due to both natural and anthropogenic aerosols are manifest in the satellite observations, the naturally occurring sea-salt is the leading aerosol contributor to the global-mean dear-sky radiation balance over oceans. C1 Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. United Kingdom Meteorol Off, Meteorol Res Flight, Farnborough GU14 0LX, Hants, England. RP Ramaswamy, V (reprint author), Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. EM vr@gfdl.gov NR 39 TC 206 Z9 212 U1 4 U2 16 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 FEB 26 PY 1999 VL 283 IS 5406 BP 1299 EP 1303 DI 10.1126/science.283.5406.1299 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 171AM UT WOS:000078839900034 ER PT J AU Gibaud, A Sella, C Maaza, M Sung, L Dura, JA Satija, SK AF Gibaud, A Sella, C Maaza, M Sung, L Dura, JA Satija, SK TI Neutron and X-ray reflectivity analysis of ceramic-metal materials SO THIN SOLID FILMS LA English DT Article DE X-ray scattering; platinum; ceramic-metal; X-ray reflectivity ID OFF-SPECULAR REFLECTIVITY; GRAZING-INCIDENCE; SCATTERING; SURFACES AB Neutron and X-ray reflectivity measurements of a thin film of cermet (ceramic-metal) made by co-sputtering Pt and Al2O3 on the surface of a flat piece of float glass are presented. From the analysis of the specular and off-specular measurements, the morphology of the Pt clusters which are embedded in the Al2O3 matrix is determined by adjusting a model to the observed data. It is found that the structure of such films presents a certain degree of order in the direction normal to the surface of the films but no correlation (or with a very short correlation length not measurable by this technique) in the plane of the film. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Maine, Fac Sci, CNRS, UPRESA 6087, F-72085 Le Mans 09, France. Univ Paris 06, Lab Opt Solides, F-75006 Paris, France. Univ Witwatersrand, Dept Phys, Johannesburg, South Africa. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Gibaud, A (reprint author), Univ Maine, Fac Sci, CNRS, UPRESA 6087, F-72085 Le Mans 09, France. RI Dura, Joseph/B-8452-2008; oudin, olivier/G-4613-2015 OI Dura, Joseph/0000-0001-6877-959X; NR 11 TC 12 Z9 13 U1 0 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD FEB 26 PY 1999 VL 340 IS 1-2 BP 153 EP 158 DI 10.1016/S0040-6090(98)01409-6 PG 6 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 179WM UT WOS:000079353000026 ER PT J AU Kellogg, CB Irikura, KK AF Kellogg, CB Irikura, KK TI Gas-phase thermochemistry of iron oxides and hydroxides: Portrait of a super-efficient flame suppressant SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID DENSITY-FUNCTIONAL CALCULATIONS; MOLECULAR-ORBITAL METHODS; DISSOCIATION-ENERGIES; ELECTRONIC-STRUCTURE; OXYGEN MOLECULES; INFRARED-SPECTRA; GROUND-STATE; BASIS-SETS; FEH; 1ST-ROW AB In the search for non-ozone-depleting Halon (CF3Br) replacements, several metals, including iron, have been identified as super-efficient flame suppressants. Although some thermochemical data exist for the species that are thought to be most important in iron's flame chemistry, a more complete and accurate characterization of the thermochemistry of iron oxides, hydrides, and hydroxides is required to improve kinetic flame models. In this investigation predicted enthalpies (Delta(rxn)H(0)degrees) and free energies (Delta(rxn)G(1500)degrees) of the reactions of several FeOxHy species in methane flames are reported. Heats of formation (Delta(f)H(0)degrees) for the FeOxHy species of interest are also recommended. The hybrid B3LYP density-functional method and the CCSD(T) coupled-cluster method are employed in conjunction with a relativistic effective core potential on the iron center and a valence triple-zeta basis on all atoms in order to characterize the relative energetics of the important species. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Kellogg, CB (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 47 TC 50 Z9 50 U1 3 U2 11 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 25 PY 1999 VL 103 IS 8 BP 1150 EP 1159 DI 10.1021/jp9842749 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 174BR UT WOS:000079014700022 ER PT J AU Slusher, JT Mountain, RD AF Slusher, JT Mountain, RD TI A molecular dynamics study of a reversed-phase liquid chromatography model SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID POLYCYCLIC AROMATIC-HYDROCARBONS; STATIONARY-PHASE; BONDED PHASES; MOBILE PHASES; TEMPERATURE-DEPENDENCE; ORIENTATIONAL DYNAMICS; RETENTION MECHANISM; COMPUTER-SIMULATION; WATER; SURFACE AB We describe a molecular dynamics simulation study of a model of the reversed-phase chromatographic system. The model consists of a slab of aqueous solvent sandwiched between two walls having attached Cg hydrocarbon chains at a surface coverage of 5.09 mu moL/m(2) or 32.6 A degrees(2)/chain. Long-ranged Coulombic interactions are taken into account using the Ewald sum method of Rhee et al. [Phys. Ret B 1989, 40, 36]. The density and solvent orientation profiles are computed as a function of distance from the walls. The density profiles are found to be sensitive to the treatment of the long-ranged electrostatic interactions. The presence of an organic cosolvent (methanol or acetonitrile) at 30.8 mol % has little effect on the chain structure, which is largely collapsed against the walls. We also estimate the change in residual Helmholtz free energy along the pore width for a methane solute in the acetonitrile/water system, which indicates that a substantial portion of the free energy driving force for retention occurs in an organic-rich layer of solvent adsorbed to the hydrocarbon phase. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Mountain, RD (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 100 Bur Dr,Stop 8380, Gaithersburg, MD 20899 USA. EM RMountain@nist.gov NR 61 TC 49 Z9 50 U1 1 U2 6 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 FEB 25 PY 1999 VL 103 IS 8 BP 1354 EP 1362 DI 10.1021/jp984003y PG 9 WC Chemistry, Physical SC Chemistry GA 174BT UT WOS:000079014800022 ER PT J AU Deakyne, CA Meot-Ner, M AF Deakyne, CA Meot-Ner, M TI Ionic hydrogen bonds in bioenergetics. 4. Interaction energies of acetylcholine with aromatic and polar molecules SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CRYSTAL-STRUCTURE; CONFORMATIONAL-ANALYSIS; SUBSTRATE-SPECIFICITY; PROTON-TRANSFER; ACTIVE-SITE; GAS-PHASE; BENZENE; RESIDUES; BINDING; IDENTIFICATION AB The binding energies of the quaternary ions(CH3)(4)N+ and acetylcholine (ACh) to neutral molecules have been measured by pulsed high-pressure mass spectrometry and calculated ab initio, to model interactions in the acetylcholine receptor channel, Binding energies to C6H6 and C6H5CH3 are similar to those to H2O (33-42 kJ/mol (8-10 kcal/mol)), but are weaker than those to polar organic ligands such as CH3CO2CH3 (50-63 kJ/mol (12-15 kcal/mol)) and to amides (up to 84 kJ/mol (20 kcal/mol)). These data suggest that aromatic residues that line the groove leading to the ACh receptor site may provide stabilization comparable to water, and therefore allow entry from the aqueous environment, yet do not bind ACh as strongly as polar protein groups, and therefore allow transit, without trapping, to the receptor site. Four of the five distinct ACh conformers located computationally are stabilized by internal C-H ... O hydrogen bonds involving the quaternary ammonium group, which is supported by the thermochemistry of the protonated analogue, CH3CO2CH2CH2N(CH3)(2)H+, and by the measured bonding energy between models of the ACh end groups, (CH3)(4)N+ and CH3CO2CH3. Each conformer forms a number of stable complexes with water or benzene. Several possible roles for an ACh conformational change upon entry into the channel are discussed, including partial compensation for the loss of bulk solvation. An additional role for the aromatic environment is also suggested, namely lowering the energy barrier to the formation of the active all-trans ACh rotamer required at the receptor site. C1 Eastern Illinois Univ, Dept Chem, Charleston, IL 61920 USA. NIST, Div Chem Kinet & Thermodynam, Gaithersburg, MD 20899 USA. RP Deakyne, CA (reprint author), Eastern Illinois Univ, Dept Chem, Charleston, IL 61920 USA. NR 62 TC 28 Z9 28 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 24 PY 1999 VL 121 IS 7 BP 1546 EP 1557 DI 10.1021/ja982549s PG 12 WC Chemistry, Multidisciplinary SC Chemistry GA 173HE UT WOS:000078974400016 ER PT J AU Karim, A Douglas, JF Satija, SK Han, CC Goyette, RJ AF Karim, A Douglas, JF Satija, SK Han, CC Goyette, RJ TI Frustrated coalescence in a chemically reactive polymer blend film SO MACROMOLECULES LA English DT Article ID PHASE-SEPARATION KINETICS; POLY(METHYL METHACRYLATE); SPINODAL DECOMPOSITION; IMMISCIBILITY LOOP; BINARY-MIXTURES; BLOCK-COPOLYMER; SOAP BUBBLES; POLYCARBONATE; DYNAMICS; SURFACTANTS AB The phase separation of a thin polymer blend layer undergoing a simultaneous transesterification reaction is examined by a variety of experimental techniques [neutron and X-ray reflectivity, optical microscopy, atomic force microscopy (AFM)] to determine morphological features unique to reactive phase separation. Neutron reflectivity measurements suggest; that a copolymer layer reactively forms at the interface between the phase-separating blend components. Evidence for a copolymer layer is also provided by AFM and optical images which indicate a strong inhibition ("frustration") of droplet coalescence and a tendency of the droplets to cluster in late-stage phase separation. The influence of the transesterification reaction on phase separation is found to depend strongly on temperature. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. Argonne Natl Lab, Div Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP Karim, A (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 69 TC 13 Z9 13 U1 3 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 23 PY 1999 VL 32 IS 4 BP 1119 EP 1127 DI 10.1021/ma980296h PG 9 WC Polymer Science SC Polymer Science GA 170KK UT WOS:000078804700021 ER PT J AU Ozbay, E Kimukin, I Biyikli, N Aytur, O Gokkavas, M Ulu, G Unlu, MS Mirin, RP Bertness, KA Christensen, DH AF Ozbay, E Kimukin, I Biyikli, N Aytur, O Gokkavas, M Ulu, G Unlu, MS Mirin, RP Bertness, KA Christensen, DH TI High-speed > 90% quantum-efficiency p-i-n photodiodes with a resonance wavelength adjustable in the 795-835 nm range SO APPLIED PHYSICS LETTERS LA English DT Article ID PHOTODETECTORS; PRODUCT AB We report GaAs/AlGaAs-based high-speed, high-efficiency, resonant cavity enhanced p-i-n photodiodes. The devices were fabricated by using a microwave-compatible fabrication process. By using a postprocess recess etch, we tuned the resonance wavelength from 835 to 795 nm while keeping the peak efficiencies above 90%. The maximum quantum efficiency was 92% at a resonance wavelength of 823 nm. The photodiode had an experimental setup-limited temporal response of 12 ps. When the system response is deconvolved, the 3 dB bandwidth corresponds to 50 GHz, which is in good agreement with our theoretical calculations. (C) 1999 American Institute of Physics. [S0003-6951(99)03708-0]. C1 Bilkent Univ, Dept Phys, TR-06533 Ankara, Turkey. Bilkent Univ, Dept Elect & Elect Engn, TR-06533 Ankara, Turkey. Boston Univ, Dept Elect & Comp Engn, Boston, MA 02215 USA. Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Ozbay, E (reprint author), Bilkent Univ, Dept Phys, TR-06533 Ankara, Turkey. EM ozbay@fen.bilkent.edu.tr RI Ozbay, Ekmel/B-9495-2008; Unlu, Selim/B-4244-2013; OI Mirin, Richard/0000-0002-4472-4655 NR 14 TC 34 Z9 36 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 22 PY 1999 VL 74 IS 8 BP 1072 EP 1074 PG 3 WC Physics, Applied SC Physics GA 168HG UT WOS:000078685700006 ER PT J AU Nishimura, H Huo, WM Ali, MA Kim, YK AF Nishimura, H Huo, WM Ali, MA Kim, YK TI Electron-impact total ionization cross sections of CF4, C2F6, and C3F8 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MOLECULES; ENERGY; DISSOCIATION; THRESHOLD; ATOMS; MODEL AB Both theoretical and experimental electron-impact total ionization cross sections of CF4, C2F6, and C3F8 are presented. The experimental cross sections have been measured as a function of incident electron energy T from threshold to 3 keV. A parallel plate condenser type apparatus was used. The molecular polarizability for C3F8 was empirically estimated to be alpha = 10.6 Angstrom(3) +/- 0.8 Angstrom(3). Theoretical cross sections calculated from the binary-encounter-Bethe (BEB) method, which combines a modified form of the Mott cross section and the Bethe cross section, are compared with the experimental cross sections. The BEB cross sections calculated from correlated molecular wave functions with theoretical estimates for multiple ionization are about 10% higher than the experimental data at the peak for CF4, while they are in excellent agreement with the experimental data for C2F6 and C3F8. Our analysis shows that the BEB theory implicitly includes part of neutral dissociation, such as CF4 --> CF3 + F, and hence tends to be an upper limit to the total ionization cross section. We found that the difference between our best theory for CF4 and the present experimental cross section exhibits a remarkable similarity to the shape of the recently measured cross section for neutral dissociation, though there is no a priori reason for the similarity. Owing to the large number of bound electrons, the correlation included in our wave functions for C2F6 and C3F8 is more limited than for CF4. Hence, we believe that for these two molecules the calculated cross sections are lower than the true BEB values, in spite of the apparent excellent agreement between the theory and the experiment. (C) 1999 American Institute of Physics. [S0021-9606(99)01608-6]. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Niigata Univ, Dept Phys, Niigata 95021, Japan. RP Nishimura, H (reprint author), Niigata Univ, Dept Phys, Niigata 95021, Japan. NR 43 TC 71 Z9 71 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 22 PY 1999 VL 110 IS 8 BP 3811 EP 3822 DI 10.1063/1.478270 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 168AX UT WOS:000078668900024 ER PT J AU Xu, LH Lees, RM Hougen, JT AF Xu, LH Lees, RM Hougen, JT TI On the physical interpretation of torsion-rotation parameters in methanol and acetaldehyde: Comparison of global fit and ab initio results SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INTERNAL-ROTATION; MOLECULE; ROTOR; SPECTRUM; STATES; TRANSITIONS; MILLIMETER; ORDER AB Equilibrium structural constants and certain torsion-rotation interaction parameters have been determined for methanol and acetaldehyde from ab initio calculations using GAUSSIAN 94. The substantial molecular flexing which occurs in going from the bottom to the top of the torsional potential barrier can be quantitatively related to coefficients of torsion-rotation terms having a (1-cos 3 gamma) dependence on torsional angle gamma. The barrier height, six equilibrium structural constants characterizing the bottom of the potential well, and six torsion-rotation constants are all compared to experimental parameters obtained from global fits to large microwave and far-infrared data sets for methanol and acetaldehyde. The rather encouraging agreement between the Gaussian and global fit results for methanol seems both to validate the accuracy of ab initio calculations of these parameters, and to demonstrate that the physical origin of these torsion-rotation interaction terms in methanol lies primarily in structural relaxation with torsion. The less satisfactory agreement between theory and experiment for acetaldehyde requires further study. (C) 1999 American Institute of Physics. [S0021-9606(99)00308-6]. C1 Univ New Brunswick, Dept Phys Sci, St John, NB E2L 4L5, Canada. Univ New Brunswick, Dept Phys, Fredericton, NB E3B 5A3, Canada. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Xu, LH (reprint author), Univ New Brunswick, Dept Phys Sci, St John, NB E2L 4L5, Canada. RI Xu, Li-Hong/J-5095-2015 NR 28 TC 46 Z9 46 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 22 PY 1999 VL 110 IS 8 BP 3835 EP 3841 DI 10.1063/1.478272 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 168AX UT WOS:000078668900026 ER PT J AU Mitra, K Churnside, JH AF Mitra, K Churnside, JH TI Transient radiative transfer equation applied to oceanographic lidar SO APPLIED OPTICS LA English DT Article ID FISH SCHOOLS; SCATTERING; OCEAN; LIGHT; PROFILES; MODELS; MEDIA AB We estimate the optical signal for an oceanographic lidar from the one-dimensional transient (time-dependent) radiative transfer equation using the discrete ordinates method. An oceanographic lidar directs a pulsed blue or green laser into the ocean and measures the time-dependent-backscattered light. A large number of parameters affect the performance of such a system. Here the optical signal that is available to the receiver is calculated, rather than the receiver output, to reduce the number of parameters. The effects of albedo of a uniform water column are investigated. The effects of a school of fish in the water are also investigated for various school depths, thicknesses, and densities. The attenuation of a lidar signal is found to be greater than the diffuse attenuation coefficient Bt low albedo and close to it at higher albedo. The presence of fish in the water is found to have a significant effect on the signal at low to moderate albedo, but not at high albedo. C1 Florida Inst Technol, Mech Engn Program, Melbourne, FL 32901 USA. NOAA, Environm Technol Labs, Boulder, CO 80303 USA. RP Mitra, K (reprint author), Florida Inst Technol, Mech Engn Program, 150 W Univ Blvd, Melbourne, FL 32901 USA. RI Churnside, James/H-4873-2013; Mitra, Kunal/C-6560-2016 OI Mitra, Kunal/0000-0002-7277-4908 NR 23 TC 31 Z9 31 U1 0 U2 1 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 FEB 20 PY 1999 VL 38 IS 6 BP 889 EP 895 DI 10.1364/AO.38.000889 PG 7 WC Optics SC Optics GA 169GQ UT WOS:000078739500001 PM 18305688 ER PT J AU Begelman, MC AF Begelman, MC TI A model for the moving "wisps" in the Crab Nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE instabilities; ISM, individual (Crab Nebula); ISM, jets and outflows; pulsars, individual (Crab Nebula); radiation mechanisms, nonthermal ID SPATIAL STABILITY; SLAB JET; MAGNETIC-FIELD; PULSAR WINDS; INSTABILITY; FLOWS AB I propose that the moving "wisps" near the center of the Crab Nebula result from nonlinear Kelvin-Helmholtz instabilities in the equatorial plane of the shocked pulsar wind. Recent observations suggest that the wisps trace out circular wave fronts in this plane, expanding radially at speeds less than or similar to c/3. Instabilities could develop if there is sufficient velocity shear between a faster moving equatorial zone and a slower moving shocked pulsar wind at higher latitudes. The development of shear could be related to the existence of a neutral sheet-with a weak magnetic field-in the equatorial zone, and could also be related to a recent suggestion in the literature that the magnetic field in the Crab pulsar wind is much stronger than had been thought. I show that plausible conditions could lead to the growth of instabilities at the radii and speeds observed, and that their nonlinear development could lead to the appearance of sharp wisplike features. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. RP Begelman, MC (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 22 TC 27 Z9 27 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1999 VL 512 IS 2 BP 755 EP 760 DI 10.1086/306801 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 187VP UT WOS:000079809000021 ER PT J AU Proffitt, CR Brage, T Leckrone, DS Wahlgren, GM Brandt, JC Sansonetti, CJ Reader, J Johansson, SG AF Proffitt, CR Brage, T Leckrone, DS Wahlgren, GM Brandt, JC Sansonetti, CJ Reader, J Johansson, SG TI Mercury in the HgMn stars chi Lupi and HR 7775 SO ASTROPHYSICAL JOURNAL LA English DT Article DE diffusion; stars : abundances; stars : individual (chi Lupi, HR 7775); stars : peculiar ID MULTICONFIGURATIONAL DIRAC-FOCK; MODEL STELLAR ATMOSPHERES; LIGHT-INDUCED DRIFT; AP STARS; ABUNDANCE; SPECTRA; LINES; WAVELENGTHS; DIFFUSION; ANOMALIES AB Observations of mercury lines in the HgMn stars chi Lupi and HR 7775 made with the Hubble Space Telescope Goddard High Resolution Spectrograph are presented and analyzed. In chi Lupi we find that all observed lines are consistent with the same isotopic mixture (essentially pure (204)Hg). Strong ionization anomalies are present, with UV Hg I lines being too weak and Hg III lines too strong for the abundance derived from lines of the majority ionization state, Hg rr. Observations of mercury in I;IR 7775 show less extreme isotope and ionization anomalies. We find that the ionization anomaly in the Hg I resonance lines can be plausibly explained as a non-LTE effect, but the same non-LTE calculations show that the Hg III ionization anomaly in chi Lupi cannot be explained in this way. Radiative force calculations show that the observed mercury abundance cannot be supported in the atmosphere by the radiative forces alone. We suggest that weak mixing brings mercury into the line-forming region from below the photosphere, while a wind of order 10(-14) M. yr(-1) supports a cloud of Hg III at very small optical depths. C1 Comp Sci Corp, Sci Program, Cincinnati, OH 45202 USA. Lund Univ, Dept Phys, S-22100 Lund, Sweden. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Proffitt, CR (reprint author), Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. EM hrsproffitt@hrs.gsfc.nasa.gov; brage@kurslab.fysik.lu.se; hrsleckrone@hrs.gsfc.nasa.gov; spek_glenn@garbo.lucas.lu.se; brandt@lyrae.colorado.edu; Craig.Sansonetti@nist.gov; Joseph.Reader@nist.gov; spek_sej@garbo.lucas.lu.se NR 58 TC 56 Z9 57 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 1999 VL 512 IS 2 BP 942 EP 960 DI 10.1086/306783 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 187VP UT WOS:000079809000036 ER PT J AU Yienger, JJ Klonecki, AA Levy, H Moxim, WJ Carmichael, GR AF Yienger, JJ Klonecki, AA Levy, H Moxim, WJ Carmichael, GR TI An evaluation of chemistry's role in the winter-spring ozone maximum found in the northern midlatitude free troposphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; CHEMICAL-TRANSPORT MODEL; ATLANTIC OCEAN; SURFACE OZONE; NOX; CLIMATOLOGY; DISTRIBUTIONS; ATMOSPHERE; SIMULATION; EMISSIONS AB We employ the Geophysical Fluid Dynamics Laboratory global chemical transport model to investigate the contribution of photochemistry to the winter-spring ozone maximum in the northern hemisphere (NH) midlatitude free troposphere (770-240 mbar; 30 degrees N-60 degrees N). Free tropospheric ozone mass slowly builds up in the winter and early spring, with net chemistry and transport playing comparable roles. Winter and early spring conditions are favorable to net ozone production for two reasons: (1)Winter conditions (cold, low Sun angle, and dry) reduce HOx and lower the level of NOx needed for chemical production to exceed destruction (balance point); and (2) throughout the winter and early spring, NOx, because of its longer chemical lifetime, increases above normally net-destructive levels in the remote atmosphere. Interestingly, net production in the midlatitude NH free troposphere maximizes in early spring because relatively high NOx and low balance point conditions are present at a time when increasing insolation is speeding up photochemistry. Conceptually, the net ozone production is associated with an annual atmospheric "spring cleaning" in which high levels of NOx are removed via OH oxidation. Further, we find that human activity has a major impact on both the levels of tropospheric ozone and the role of chemistry in the NH midlatitude, where anthropogenic NOx emissions dominate. In that region, modern ozone levels have increased by similar to 20% in the winter and similar to 45% in the spring, winter-spring chemistry has switched from net destructive to net productive, the winter-spring balance between transport and chemistry has switched from transport dominance in preindustrial times to the present parity, and the preindustrial February maximum has progressed to March-April. Estimated 2020 levels of NOx emissions were found to lead to even greater net production and to push the O-3 spring maximum later into April-May. C1 Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08542 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Yienger, JJ (reprint author), Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. EM jyienger@cgrer.uiowa.edu; aak@gfdl.gov; hl@gfdl.gov; wm@gfdl.gov; gcarmich@icaen.uiowa.edu NR 45 TC 58 Z9 58 U1 0 U2 6 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 FEB 20 PY 1999 VL 104 IS D3 BP 3655 EP 3667 DI 10.1029/1998JD100043 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168RN UT WOS:000078706600017 ER PT J AU Eder, BK LeDuc, SK Sickles, JE AF Eder, BK LeDuc, SK Sickles, JE TI A climatology of total ozone mapping spectrometer data using rotated principal component analysis SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; NINO-SOUTHERN OSCILLATION; EASTERN-UNITED-STATES; STRATOSPHERIC OZONE; TRENDS; HEMISPHERE; DEPLETION; WAVES; SBUV AB The spatial and temporal variability of total column ozone (Omega) obtained from the total ozone mapping spectrometer (TOMS version 7.0) during the period 1980-1992 was examined through the use of a multivariate statistical technique called rotated principal component analysis. Utilization of Kaiser's varimax orthogonal rotation led to the identification of 14, mostly contiguous subregions that together accounted for more than 70% of the total Omega variance. Each subregion displayed statistically unique Omega characteristics that were further examined through time series and spectral density analyses, revealing significant periodicities on semiannual, annual, quasi-biennial, and longer term time frames. This analysis facilitated identification of the probable mechanisms responsible for the variability of Omega within the 14 homogeneous subregions. The mechanisms were either dynamical in nature (i.e., advection associated with baroclinic waves, the quasi-biennial oscillation, or El Nino-Southern Oscillation) or photochemical in nature (i.e., production of odd oxygen (O or O-3) associated with the annual progression of the Sun). The analysis has also revealed that the influence of a data retrieval artifact, found in equatorial latitudes of version 6.0 of the TOMS data, has been reduced in version 7.0. C1 NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27711 USA. US EPA, Natl Exposure Res Lab, Div Environm Sci, Res Triangle Pk, NC 27711 USA. RP Eder, BK (reprint author), NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Mail Drop 80, Res Triangle Pk, NC 27711 USA. NR 43 TC 9 Z9 9 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 FEB 20 PY 1999 VL 104 IS D3 BP 3691 EP 3709 DI 10.1029/1998JD100070 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168RN UT WOS:000078706600019 ER PT J AU Nevison, CD Solomon, S Gao, RS AF Nevison, CD Solomon, S Gao, RS TI Buffering interactions in the modeled response of stratospheric O-3 to increased NOx and HOx SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU MEASUREMENTS; OZONE DEPLETION; MIDDLE ATMOSPHERE; PERTURBATIONS; TRANSPORT; CHEMISTRY; NITROGEN; REMOVAL; HALOGEN; N2O AB The response of stratospheric O-3 to changes in NOx and HOx is tested in a two-dimensional model with the goal of exploring photochemical buffering mechanisms. The model tests are performed under background aerosol conditions at both current (1996) and preindustrial levels of stratospheric halogens. The tests are prompted in part by comparisons to observations from the POLARIS (Polar Ozone Loss in the Arctic Region in Summer) high-altitude aircraft campaign, which show that models significantly underestimate the NOx/NOy ratio in the lower stratosphere but are more successful at reproducing observed O-3. Model tests with increased NOx show that increases in NOx-catalyzed O-3 loss are subject to photochemical buffering in the lower stratosphere through reduced HOx-catalyzed O-3 loss and at current halogen levels, reduced halogen-catalyzed O-3 loss. In contrast these tests show that O-3 is not well buffered with respect to increased NOx in the middle stratosphere, especially at preindustrial halogen levels. Consequently, an NOy increase that reaches the middle stratosphere could: lead to modest depletion of column O-3, while an NOy increase confined to the lower stratosphere more likely would have a neutral or slightly positive effect on column O-3. These results are only mildly sensitive to uncertainties in the NOx/NOy ratio. Additional model tests with increased HOx show some photochemical buffering, but generally lead to mixed effects on O-3 which depend on the nature of the HOx source gas. This source gas dependence is especially strong at current halogen levels. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Nevison, CD (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM nevison@ucar.edu RI Gao, Ru-Shan/H-7455-2013 NR 37 TC 18 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 20 PY 1999 VL 104 IS D3 BP 3741 EP 3754 DI 10.1029/1998JD100018 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 168RN UT WOS:000078706600022 ER PT J AU Gierczak, T Burkholder, JB Ravishankara, AR AF Gierczak, T Burkholder, JB Ravishankara, AR TI Temperature dependent rate coefficient for the reaction O(P-3)+NO2 -> NO+O-2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CROSS-SECTIONS; RATE CONSTANTS; NO2; KINETICS; N2O4 AB The rate coefficient (k(1)) for the reaction O(P-3) + NO2 --> O-2 + NO was measured under pseudo-first-order conditions in O(P-3) atom concentration over the temperature range 220-412 K. Measurements were made using pulsed laser photolysis of NO2 to produce oxygen atoms and time-resolved vacuum UV resonance fluorescence detection of O atoms. The NO2 concentration was measured using three techniques: flow rate, UV absorption, and chemical titration (NO + O-3 --> NO2 + O-2) The NO2 UV absorption cross section at 413.4 nm was determined as a function of temperature using the chemical titration and flow methods. Including the low-temperature data of Harder et al.(1), the temperature-dependent NO2 cross section is given by sigma(413.4)(T) (9.49 - 0.00549 T) x 10(-19) cm(2) molecule(-1). The measured rate coefficients for reaction 1 can be expressed as k(1)(T) = (5.26 +/- 0.60) x 10(-12) exp[(209 +/- 35)/T] cm(3) molecule(-1) s(-1), where the quoted uncertainties are 2 sigma and include estimated systematic errors. This result is compared with previously reported measurements of k(1). C1 NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Warsaw, Dept Chem, PL-02089 Warsaw, Poland. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Ravishankara, AR (reprint author), NOAA, ERL, Aeron Lab, R-E-AL2,325 Broadway, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 18 TC 43 Z9 46 U1 0 U2 0 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 FEB 18 PY 1999 VL 103 IS 7 BP 877 EP 883 DI 10.1021/jp983962p PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 176KG UT WOS:000079149800016 ER PT J AU Poirier, GE AF Poirier, GE TI Coverage-dependent phases and phase stability of decanethiol on Au(111) SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; SCANNING-TUNNELING-MICROSCOPY; CHAIN-LENGTH DEPENDENCE; N-ALKYL THIOLS; ALKANETHIOL MONOLAYERS; ADSORPTION-KINETICS; GOLD SURFACES; SPECTROSCOPY; SUPERLATTICE; TRANSITIONS AB Using ultrahigh vacuum scanning tunneling microscopy, we have characterized the structural phases of decanethiol on Au( 111) at coverages below saturation. As coverage increases, the monolayer sequentially adopts five discrete structural phases. At low surface coverage, decanethiol exists as a lattice gas. Above a critical surface coverage, the molecules condense into islands of a commensurate crystalline lattice. These islands grow in equilibrium with the lattice gas until saturation. As coverage increases, the surface layer sequentially undergoes two first-order phase transitions, first to a metastable phase then to a stable phase. The first three condensed phases are characterized by alignment of the molecular axes with the surface plane but with discretely increasing degrees of out-of-plane interdigitation. Above saturation coverage of the densest surface-aligned phase, the monolayer undergoes an edge-mediated melting transition. The evidence suggests that the resulting fluid is a supercooled, two-dimensional liquid. The highest-density phase, characterized by alignment of the molecular axes close to the surface normal, grows by homogeneous nucleation from this supercooled liquid. These data provide a fundamental understanding of the mechanistic pathway of molecular monolayer self-assembly. C1 NIST, Gaithersburg, MD 20899 USA. RP Poirier, GE (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 43 TC 210 Z9 210 U1 2 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD FEB 16 PY 1999 VL 15 IS 4 BP 1167 EP 1175 DI 10.1021/la981374x PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 168GB UT WOS:000078682400043 ER PT J AU Barnston, AG Kumar, A AF Barnston, AG Kumar, A TI Comment on "A three-year lagged correlation between the North Atlantic Oscillation and winter conditions over the North Pacific and North America" SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material ID TEMPERATURE; ATMOSPHERE; OCEAN C1 NOAA, NCEP, Climate Predict Ctr, Camp Springs, MD 20746 USA. NOAA, NCEP, Expt Modeling Ctr, Camp Springs, MD 20746 USA. RP Barnston, AG (reprint author), NOAA, NCEP, Climate Predict Ctr, 5200 Auth Rd,Room 604, Camp Springs, MD 20746 USA. EM Anthony.Barnston@ncep.noaa.gov; Arun.Kumar@ncep.noaa.gov NR 13 TC 2 Z9 2 U1 0 U2 0 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 FEB 15 PY 1999 VL 26 IS 4 BP 475 EP 476 DI 10.1029/1999GL900007 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 167EW UT WOS:000078620400011 ER PT J AU Kent, MS Majewski, J Smith, GS Lee, LT Satija, S AF Kent, MS Majewski, J Smith, GS Lee, LT Satija, S TI Tethered chains in poor solvent conditions: An experimental study involving Langmuir diblock copolymer monolayers SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID GRAFTED POLYMER LAYERS; MONTE-CARLO SIMULATION; NEUTRON REFLECTIVITY; PHASE-TRANSITION; COLLAPSED REGIME; BRUSH LAYERS; SURFACE; THETA; QUALITY; FIELD AB We have employed Langmuir monolayers of highly asymmetric polydimethylsiloxane-polystyrene (PDMS-PS) diblock copolymers on dioctyl phthalate (DOP) at temperatures ranging from 22 to -35 degrees C as a model system for tethered chains in poor solvent conditions. The thicknesses of the tethered PS layers extending into the DOP subphase, measured by neutron reflection, decrease with decreasing temperature (T) over this entire range. However, the variation with T becomes weak below -20 degrees C. At the lowest T, the layer thicknesses are 55%-75% of the values at the theta condition (T-theta = 22 degrees C). The contraction of the layer with decreasing T is determined as a function of surface density and molecular weight, and these data are compared to universal scaling forms. The PS segments are depleted from the near surface region over the entire T range, with the thickness of the depletion layer increasing slightly with decreasing T. The free energy of the surface layer is probed by surface tension measurements. With decreasing T, negative surface pressures are observed at low coverages for both PDMS-PS and PDMS monolayers, indicating metastability toward lateral phase separation. Evidence for a transition from a dispersed phase to a condensed phase with decreasing T was observed in the reflectivity for very low PDMS-PS coverage. At high coverage where the submerged blocks are strongly interacting at 22 degrees C, only a modest decrease in surface pressure is observed over the experimental range of T despite the strong contraction. This latter result is discussed in terms of the relative contributions of enthalpic and entropic effects to the surface pressure. (C) 1999 American Institute of Physics. [S0021-9606(99)51501-8]. C1 Sandia Natl Labs, Albuquerque, NM 87185 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CENS, Lab Leon Brillouin, F-91191 Gif Sur Yvette, France. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Kent, MS (reprint author), Sandia Natl Labs, POB 5800, Albuquerque, NM 87185 USA. RI Lujan Center, LANL/G-4896-2012 NR 61 TC 11 Z9 11 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD FEB 15 PY 1999 VL 110 IS 7 BP 3553 EP 3565 DI 10.1063/1.478223 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 164DA UT WOS:000078446100033 ER PT J AU Kropfli, RA Ostrovski, LA Stanton, TP Skirta, EA Keane, AN Irisov, V AF Kropfli, RA Ostrovski, LA Stanton, TP Skirta, EA Keane, AN Irisov, V TI Relationships between strong internal waves in the coastal zone and their radar and radiometric signatures SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SURFACE WIND WAVES; SOLITONS; OCEAN; MODEL; SHIP; LOCH; SEA AB Strong internal waves (IW) in the form of soliton groups were observed off the Oregon coast with in situ and remote sensors, including shore-based X band and K-a band Doppler radars and an airborne microwave radiometer operating at 37 GHz. Here we analyze the relationships between oceanic isotherm vertical displacements, internal currents, and radar backscatter cross sections, along with Doppler velocity signals at horizontal (HH) and vertical (VV) polarizations, and 37-GHz brightness temperatures measured at intermediate incidence angles from an airship. Analysis of these observations shows that (1) the horizontal spatial structure of the IW field depends on whether it is forced by a strong (spring) tide or weak (neap) tide; (2) while both HH and VV are strongly modulated by IWs, the modulation depth of HH always exceeds that of VV, and they both increase with the IW amplitude; (3) 37-GHz brightness temperature modulations were in phase with radar signal modulations; and (4) the phase of radar signal modulation with respect to the IW is such that the minimum radar signal intensity and lowest microwave brightness temperature lie close to the maximum of the IW thermocline depression or, equivalently, the horizontal current excursion near the surface. This last observation conflicts with the expectation that the highest backscattered signal would be found near the region of greatest surface strain rate (the surface current gradient), Existing theoretical models are briefly reviewed for interactions between the IW field and the intensity of short gravity-capillary waves that might be responsible for this behavior. C1 NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. Univ Toledo, Coll Arts & Sci, Dept Math, Toledo, OH 43606 USA. USN, Postgrad Sch, Dept Oceanog, Monterey, CA 93943 USA. RP Kropfli, RA (reprint author), NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, R-E-ET6,325 Broadway, Boulder, CO 80303 USA. NR 27 TC 55 Z9 55 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-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1999 VL 104 IS C2 BP 3133 EP 3148 DI 10.1029/98JC02549 PG 16 WC Oceanography SC Oceanography GA 166UJ UT WOS:000078595300008 ER PT J AU Lavelle, JW Wetzler, MA AF Lavelle, JW Wetzler, MA TI Diffuse venting and background contributions to chemical anomalies in a neutrally buoyant ocean hydrothermal plume SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID MID-ATLANTIC RIDGE; DE-FUCA-RIDGE; EAST PACIFIC RISE; SPATIAL VARIABILITY; AXIAL VOLCANO; CLEFT SEGMENT; FIELD; TAG; 26-DEGREES-N; CHEMISTRY AB Plumes originating in high-temperature hydrothermal discharges entrain background water and often entrain diffuse-source fluids during convective ascent. The mixing of fluid from those three different sources determines the chemical composition of the ensuing neutrally buoyant plumes. Here convection models and aluminum data from the Trans-Atlantic Geotraverse (TAG) site are used to examine relative contributions of focused, diffuse, and background sources to anomalies in the plume. Our analysis shows that anomalously high Al values observed just above the seafloor at TAG, which we assume stem from diffuse flows, can contribute as much as 50% to the Al anomaly in the neutrally buoyant plume found >350 m above bottom. Background water contributes Dearly an equal fraction of Al to the anomaly. More generally, entrained contributions depend on gradients in profiles external to the rising plume. Entrainment also depends on effective source area; distributed high-temperature vents entrain more fluid than a single, composite high-temperature vent. Larger effective source area is particularly significant for entrainment of diffuse-source or other tracers trapped within a few tens of meters of the seafloor. Downstream, cross-stream, and temporal variabilities exhibited in the three-dimensional model plume also underscore problems of sampling and interpreting actual plume data. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Lavelle, JW (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 32 TC 14 Z9 14 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-OCEANS JI J. Geophys. Res.-Oceans PD FEB 15 PY 1999 VL 104 IS C2 BP 3201 EP 3209 DI 10.1029/1998JC900063 PG 9 WC Oceanography SC Oceanography GA 166UJ UT WOS:000078595300012 ER PT J AU Hanley, HJM Muzny, CD Butler, BD Straty, GC Bartlett, J Drabarek, E AF Hanley, HJM Muzny, CD Butler, BD Straty, GC Bartlett, J Drabarek, E TI Shear-induced restructuring of concentrated colloidal silica gels SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID NEUTRON-SCATTERING; FLUIDS; SUSPENSIONS; APPARATUS; GELATION; FLOW AB The viscometric properties and structure of concentrated sheared colloidal gels, formed at a pH = 8 from a commercial aqueous sol of 7 nm diameter silica particles, were investigated. As the system gels under a constant shear rate, the viscosity first increases, then peaks when the shear stress reaches a shear-rate-independent threshold value of about 350 Pa, and finally decreases asymptotically to approximately one tenth the peak value. This low-viscosity state can apparently be held indefinitely by maintaining the shear, but the system gels once the shear is removed. The structural origins of this viscometric behaviour were studied using in situ small-angle neutron scattering (SANS). An abrupt change in the character of the SANS intensity was observed at the time corresponding to the peak in the viscosity. Samples of the gelling system were extracted and diluted at various times after gel initiation. Effective hydrodynamic diameters of these extractants were estimated by dynamic light scattering, and their Guinier diameters were estimated by SANS when appropriate. We conclude that the drop in viscosity corresponds to a structural densification of growing clusters of the colloidal particles, and that this transformation occurs once the critical stress is reached. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Australian Nucl Sci & Technol Org, Menai, NSW 2234, Australia. RP Hanley, HJM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 31 TC 20 Z9 20 U1 3 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 FEB 15 PY 1999 VL 11 IS 6 BP 1369 EP 1380 DI 10.1088/0953-8984/11/6/003 PG 12 WC Physics, Condensed Matter SC Physics GA 168LR UT WOS:000078694700003 ER PT J AU Santoro, A Natali Sora, I Huang, Q AF Santoro, A Natali Sora, I Huang, Q TI Bond-valence analysis of the structure of (Ba0.875Sr0.125)RuO3 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE structural modeling; bond-valence method; sphere packing; barium strontium ruthenium oxide ID CRYSTAL; PARAMETERS; LENGTHS AB The structure of TRuO3(T = Ba0.875Sr0.125) has been analyzed using the bond valence procedures developed by Brown [e.g., Acta Crystallogr, Sect, B 48, 553 (1992)] and O'Keeffe [Structure and Bonding 71, 161 (1989)], The experimental results, which show "overbonded" and "underbonded" T and Ru cations, respectively, are explained by the fact that the theoretical T-O and Ru-O distances that completely satisfy the valence requirements of the atoms are incommensurate under the constraints imposed by the site symmetries of the special positions occupied by the atoms. Starting from a model derived from sphere packing geometry and the theoretical bond lengths, it is possible to evaluate the lattice parameters and the atomic shifts that minimize the strains introduced into the structure by the incommensurability of the theoretical Ru-O and T-O distances, and to arrive at a model quite close to the experimental results without making use of any prior knowledge of the structure. According to this analysis, therefore, the observed structure is interpreted as resulting from a compromise between the different bond distance requirements of the Ru and T cations. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Natali Sora, I (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Bldg 235,Rm E151, Gaithersburg, MD 20899 USA. RI Natali Sora, Isabella/C-8357-2011 NR 12 TC 7 Z9 8 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD FEB 15 PY 1999 VL 143 IS 1 BP 69 EP 73 DI 10.1006/jssc.1998.8080 PG 5 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 174BF UT WOS:000079013700010 ER PT J AU Baringer, MO Price, JF AF Baringer, MO Price, JF TI A review of the physical oceanography of the Mediterranean outflow SO MARINE GEOLOGY LA English DT Article DE currents; density; Mediterranean; outflow; dynamics; circulation ID WATER; SEA; GIBRALTAR; STRAIT; CIRCULATION; OCEAN; DISSIPATION; LEVANTINE; DYNAMICS; STRESS AB The physical oceanography of the Mediterranean Sea is reviewed with particular emphasis on the Mediterranean outflow in the Gulf of Cadiz. in this region the dense Mediterranean water forms a high velocity bottom current that interacts strongly with the sea floor, The major energy source for the plume comes from the release of potential energy as the plume descends the continental slope, and the major energy sink is work against bottom stress, which is as large as 4 Pa where the plume begins to descend the continental slope. In this region the current makes a nearly inertial turn that would otherwise appear to be steered by the underlying topography. The Mediterranean plume entrains the overlying North Atlantic Central Water and thereby loses much of its density anomaly. The mixed Mediterranean water becomes neutrally buoyant in the lower portion of the North Atlantic thermocline near Cape St. Vincent. There are then two preferred transport modes having somewhat different temperature and salinity whose distinct characteristics can be found far into the open North Atlantic. The temperature, salinity and Volume of the Mediterranean water in the Strait of Gibraltar and in the Gulf of Cadiz appear to be roughly constant since modem measurements have been made. The estimated westward transport of Mediterranean water has gone down considerably as direct measurement techniques have been applied. A recent estimate is that the westward transport of pure Mediterranean water is only about a half a Sv (1 Sv = 10(6) m(3) s(-1)); the transport of mixed Mediterranean water in the western Gulf of Cadiz is larger by about a factor of three or four because of the entrainment of North Atlantic water. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02534 USA. RP NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. EM baringer@aoml.noaa.gov RI Baringer, Molly/D-2277-2012 OI Baringer, Molly/0000-0002-8503-5194 NR 95 TC 74 Z9 74 U1 1 U2 25 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0025-3227 EI 1872-6151 J9 MAR GEOL JI Mar. Geol. PD FEB 15 PY 1999 VL 155 IS 1-2 BP 63 EP 82 DI 10.1016/S0025-3227(98)00141-8 PG 20 WC Geosciences, Multidisciplinary; Oceanography SC Geology; Oceanography GA 164PJ UT WOS:000078472500005 ER PT J AU Anderson, DM Archer, RB AF Anderson, DM Archer, RB TI Preliminary evidence of early deglaciation in southern Chile SO PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY LA English DT Article DE paleoclimatology; Chile; glacial; insolation ID LAST DEGLACIATION; BAFFIN-ISLAND; OCEAN; ICE; MAGELLAN; CLIMATE; AMERICA; STRAIT; RECORD; RATES AB The end of the last ice age in the channels of southern Chile is recorded by resumed sedimentation in formerly ice-filled basins. To identify the timing of initial ice retreat in Southern Chile, we examined ice-proximal sediments from a proglacial lake along the eastern margin of the Magallanes ice sheet, an environment thought to be sensitive to initial melting (Porter, S.C,, Clapperton, C.M., Sugden, D.E., 1992. Chronology and dynamics of deglaciation along and near the Strait of Magellan, southernmost South America. Sver. Geol. Unders. 81, 233-239). AMS-radiocarbon dates of the supra-till deposits in two cores indicate that sedimentation resumed 18 radiocarbon kyr. Deposition in kettle-holes and bogs on the adjacent land surfaces began at the same time or earlier (17-25 radiocarbon kyr) (Clapperton, C.M., Sugden, D.E., Kaufman, D.S., McCulloch, R.D., 1995. The last glaciation in central Magellan Strait, Southernmost Chile. Quat. Res. 44, 133-148). Our preliminary interpretation is that these events indicate initial deglaciation in the region and the formation of a large proglacial lake, followed several thousand years later by the invasion of salt water as sea level rose. Deglaciation in southers Chile occurred too early to be forced by the resumption of North Atlantic Deep Water formation, sea level rise, or northern hemisphere summer insolation, and we suggest instead that southern insolation played a role. The time of initial deglaciation in southern Chile (21-27 calendar kyr) occurred as southern hemisphere annual insolation increased from a minimum at 29 calendar kyr (6 W/m(2) less than today at 80 degrees S). (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Paleoclimatol Program, US Dept Commerce, Boulder, CO 80303 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. RP Anderson, DM (reprint author), NOAA, Paleoclimatol Program, US Dept Commerce, 325 Broadway, Boulder, CO 80303 USA. RI anderson, david/E-6416-2011 NR 25 TC 13 Z9 13 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0031-0182 J9 PALAEOGEOGR PALAEOCL JI Paleogeogr. Paleoclimatol. Paleoecol. PD FEB 15 PY 1999 VL 146 IS 1-4 BP 295 EP 301 DI 10.1016/S0031-0182(98)00146-1 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary; Paleontology SC Physical Geography; Geology; Paleontology GA 160WB UT WOS:000078253700015 ER PT J AU Heske, C Treusch, R Himpsel, FJ Kakar, S Terminello, LJ Weyer, HJ Shirley, EL AF Heske, C Treusch, R Himpsel, FJ Kakar, S Terminello, LJ Weyer, HJ Shirley, EL TI Band widening in graphite SO PHYSICAL REVIEW B LA English DT Article ID PHOTOELECTRON ANGULAR-DISTRIBUTIONS; ANGLE-RESOLVED PHOTOEMISSION; SYNCHROTRON-RADIATION; METALS; STATES; EXCITATION; LIF(100); DIAMOND; ENERGY; NA AB The valence band width of graphite is determined with high accuracy by imaging the momentum distribution of photoelectrons for various binding energies. Compared to local-density-functional theory, the experimental band width (22.0 eV) is stretched by about 11%. Quasiparticle calculations, which properly describe electron interaction effects on the excited states of a solid, give a width of 21.8 eV, in agreement with the experiment within the experimental and theoretical relative uncertainty of about 1%. The results demonstrate the importance of including Anal-state and associated many-body effects into the theoretical description of the electronic structure of solids. [S0163-1829(99)11403-6]. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Adv Light Source, Berkeley, CA 94720 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Lawrence Livermore Natl Lab, Dept Appl Sci, Livermore, CA 94550 USA. Paul Scherrer Inst, Swiss Light Source, Villigen, Switzerland. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Univ Wurzburg, Adv Light Source, Hubland, D-97074 Wurzburg, Germany. EM heske@physik.uni-wuerzburg.de RI Treusch, Rolf/C-3935-2015; OI Treusch, Rolf/0000-0001-8479-8862 NR 27 TC 57 Z9 57 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 4680 EP 4684 DI 10.1103/PhysRevB.59.4680 PG 5 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800034 ER PT J AU Valla, T Johnson, PD Dhesi, SS Smith, KE Doppalapudi, D Moustakas, TD Shirley, EL AF Valla, T Johnson, PD Dhesi, SS Smith, KE Doppalapudi, D Moustakas, TD Shirley, EL TI Unoccupied band structure of wurtzite GaN(0001) SO PHYSICAL REVIEW B LA English DT Article ID ELECTRONIC-STRUCTURE; GAN; ABSORPTION; SURFACE; GROWTH; FILMS AB We report an inverse photoemission study of the unoccupied states of thin-film n-type wurtzite GaN. For incident electron energies below 30 eV, free-electron bands do not provide a good description of the initial state. However, using a calculated quasiparticle band structure for the initial state, we can obtain good agree ment between our measurements and the calculated low-lying conduction bands. No evidence of unoccupied surface states is observed in the probed part of the Brillouin zone, confirming earlier angle resolved photoemission studies, which identified the surface states on GaN(0001) as occupied dangling bond states, resonant with the valence band. [S0163-1829(99)09007-4]. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Boston Univ, Dept Elect & Comp Engn, Boston, MA 02215 USA. NIST, PHY B208, Gaithersburg, MD 20899 USA. RP Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Moustakas, Theodore/D-9249-2016 OI Moustakas, Theodore/0000-0001-8556-884X NR 15 TC 17 Z9 17 U1 0 U2 11 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 7 BP 5003 EP 5007 DI 10.1103/PhysRevB.59.5003 PG 5 WC Physics, Condensed Matter SC Physics GA 169YZ UT WOS:000078778800076 ER PT J AU Benedict, LX Shirley, EL AF Benedict, LX Shirley, EL TI Ab initio calculation of epsilon(2)(omega) including the electron-hole interaction: Application to GaN and CaF2 SO PHYSICAL REVIEW B LA English DT Article ID PARTICLE BAND-STRUCTURE; QUASIPARTICLE ENERGIES; DIELECTRIC FUNCTION; OPTICAL-SPECTRUM; BASIS-SETS; SEMICONDUCTORS; INSULATORS; SYSTEMS AB We present a computationally efficient first-principles scheme to calculate epsilon(2)(omega) for crystalline insulators, including the electron-hole interaction. The effective Hamiltonian for electron-hole pairs contains both the exchange and direct parts of this interaction. An iterative scheme is used in which the omega moments of epsilon(2)(omega) are computed by repeated action of the Hamiltonian on electron-hole pair states. The scheme is applied to two insulators where there are significant experimental uncertainties in their ultraviolet optical properties: GaN and CaF2. [SO163-1829(99)08507-0]. C1 Natl Inst Stand & Technol, Phys Lab, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Phys Lab, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 38 TC 126 Z9 126 U1 1 U2 7 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD FEB 15 PY 1999 VL 59 IS 8 BP 5441 EP 5451 DI 10.1103/PhysRevB.59.5441 PG 11 WC Physics, Condensed Matter SC Physics GA 173AZ UT WOS:000078959900028 ER PT J AU Anderson, DZ Brockett, RW Nuttall, N AF Anderson, DZ Brockett, RW Nuttall, N TI Information dynamics of photorefractive two-beam coupling SO PHYSICAL REVIEW LETTERS LA English DT Article ID STEADY-STATE SOLUTION; GROUP SYMMETRY; GEOMETRY; GRATINGS; FLOWS; MEDIA AB An operator approach to two-beam coupling in photorefractive media for which each beam is composed of information that varies in both space and time reduces the problem to a single differential equation: d rho/dz = [[sigma(0), rho], rho]/4. [A, B] = AB - BA is the commutator of two operators, rho is a density operator that embodies the state of the optical field, and sigma(0) is a coupling operator. A solution exists in closed form for specific cases and is amenable to numerical integration in general. The evolution of rho is unitary and approaches a block diagonal in a representation that diagonalizes sigma(0). [S0031-9007(99)08382-9]. C1 Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Harvard Univ, Div Appl Sci, Cambridge, MA 02138 USA. RP Anderson, DZ (reprint author), Univ Colorado, Dept Phys, Boulder, CO 80309 USA. NR 16 TC 10 Z9 10 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 15 PY 1999 VL 82 IS 7 BP 1418 EP 1421 DI 10.1103/PhysRevLett.82.1418 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500019 ER PT J AU Zozulya, AA Diddams, SA Van Engen, AG Clement, TS AF Zozulya, AA Diddams, SA Van Engen, AG Clement, TS TI Propagation dynamics of intense femtosecond pulses: Multiple splittings, coalescence, and continuum generation SO PHYSICAL REVIEW LETTERS LA English DT Article ID NORMALLY DISPERSIVE MEDIA; ULTRASHORT LASER-PULSES; THRESHOLD; BREAKDOWN; FIBERS AB We present a scenario of (3 + 1)-dimensional spatiotemporal dynamics of femtosecond laser pulses in a nonlinear media with normal dispersion. The sequence of events at progressively higher powers can be characterized as single splitting, multiple splitting, and coalescence. Self-focusing and splitting events are in general spatially separated. Experimental data confirm the above scenario, with measurements at the highest powers corresponding to the regime of continuum generation. [S0031-9007(99)08469-0]. C1 Worcester Polytech Inst, Dept Phys, Worcester, MA 01609 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Zozulya, AA (reprint author), Worcester Polytech Inst, Dept Phys, 100 Inst Rd, Worcester, MA 01609 USA. RI Clement, Tracy/A-8885-2008; Diddams, Scott/L-2819-2013 NR 22 TC 151 Z9 156 U1 3 U2 9 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 15 PY 1999 VL 82 IS 7 BP 1430 EP 1433 DI 10.1103/PhysRevLett.82.1430 PG 4 WC Physics, Multidisciplinary SC Physics GA 167GE UT WOS:000078623500022 ER PT J AU McPhaden, MJ AF McPhaden, MJ TI Genesis and evolution of the 1997-98 El Nino SO SCIENCE LA English DT Review ID SEA-SURFACE TEMPERATURE; WESTERN EQUATORIAL PACIFIC; ATMOSPHERE RESPONSE EXPERIMENT; MADDEN-JULIAN OSCILLATION; SOUTHERN-OSCILLATION; WARM POOL; TROPICAL PACIFIC; ENSO PREDICTION; SEASONAL CYCLE; ROSSBY WAVES AB The 1997-98 El Nino was, by some measures, the strongest on record, with major climatic impacts felt around the world. A newly completed tropical Pacific atmosphere-ocean sphere-ocean observing system documented this El Nino from its rapid onset to its sudden demise in greater detail than was ever before possible. The unprecedented measurements challenge existing theories about El Nino-related climate swings and suggest why climate forecast models underpredicted the strength of the El Nino before its onset. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP McPhaden, MJ (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. EM mcphaden@pmel.noaa.gov RI McPhaden, Michael/D-9799-2016 NR 73 TC 770 Z9 812 U1 6 U2 86 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 FEB 12 PY 1999 VL 283 IS 5404 BP 950 EP 954 DI 10.1126/science.283.5404.950 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 166KM UT WOS:000078574800038 ER PT J AU David, L Luo, R Head, MS Gilson, MK AF David, L Luo, R Head, MS Gilson, MK TI Computational study of KNI-272, a potent inhibitor of HIV-1 protease: On the mechanism of preorganization SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID TRANSITION-STATE; MOLECULAR MECHANICS; COMPLETE SEQUENCE; DYNAMICS; MODELS; ALLOPHENYLNORSTATINE; INITIATION; PROTEINS; PROGRAM; ENERGY AB The compound KNI-272 is a potent, peptide-like inhibitor of HIV protease. Its conformation when complexed with the protease is close to that which it assumes in its single-molecule crystal. This observation led to the suggestion that KNI-272 gains affinity by being preorganized for binding. On the other hand, one might well expect KNI-272 to be flexible because it possesses 15 rotatable bonds. Moreover, a recent ab initio study of KNI-272 suggests that it is not preorganized because its bound conformation is strained. Here, we use a novel algorithm to study the conformational distribution of this inhibitor. The results show good agreement with a recent NMR analysis of KNI-272 in solution. The calculations indicate that KNI-272 in solution occupies three major conformations, one of which matches the bound conformation and the NMR structure. In addition, the thioproline amide bond tends to be in the trans conformation found in the complex of KNI-272 with HIV protease. Further calculations on hypothetical analogues of KNI-272 provide information on the mechanism of preorganization and indicate that steric interactions among the bulky side chains are of particular importance. C1 Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. SmithKline Beecham Pharmaceut, King Of Prussia, PA 19406 USA. RP Gilson, MK (reprint author), 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 23 TC 11 Z9 11 U1 1 U2 1 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 FEB 11 PY 1999 VL 103 IS 6 BP 1031 EP 1044 DI 10.1021/jp983675l PG 14 WC Chemistry, Physical SC Chemistry GA 172GF UT WOS:000078914600017 ER PT J AU Mildner, DFR Chen-Mayer, HH AF Mildner, DFR Chen-Mayer, HH TI Neutron absorption measurements using converging beams - increased reaction rate SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE neutron absorption measurements; spatial resolution; prompt gamma activation analysis (PGAA); neutron depth profiling (NDP) ID GAMMA-ACTIVATION-ANALYSIS; OPTICS; LENS AB Focusing lenses using neutron reflection optics may considerably increase the neutron beam current density over a small area. The technique enables neutron absorption measurements to be taken with higher sensitivity, greater spatial resolution and lower background. Experimental concerns associated with the beam converging onto the sample are considered and compared to those for a quasi-parallel beam. In particular, we show the connection between the interaction rates for the parallel beam and the isotropic held. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mildner, DFR (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 10 TC 1 Z9 1 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 21 EP 25 DI 10.1016/S0168-9002(98)01055-9 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800006 ER PT J AU Gilliam, DM Arif, M Jacobson, DL Ioffe, A AF Gilliam, DM Arif, M Jacobson, DL Ioffe, A TI Recent experiments in neutron interferometry and optics at NIST SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN DE neutron interferometry; neutron optics; National Institute of Standards and Technology (NIST) AB The neutron interferometry and optics facility at the National Institute of Standards and Technology (NIST) has been in full operation since September 1996 as both a NIST research facility and as a national user facility. Unprecedented performance characteristics have been achieved in interferometry. A very busy schedule of experiments in fundamental physics, applied physics, and materials science has developed. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Missouri, Columbia, MO USA. NIST, Columbia, MO USA. RP Gilliam, DM (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 41 EP 42 DI 10.1016/S0168-9002(98)01058-4 PG 2 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800009 ER PT J AU Dulloo, AR Ruddy, FH Seidel, JG Adams, JM Nico, JS Gilliam, DM AF Dulloo, AR Ruddy, FH Seidel, JG Adams, JM Nico, JS Gilliam, DM TI The neutron response of miniature silicon carbide semiconductor detectors SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Symposium on Radiation Measurements and Applications CY MAY 11-14, 1998 CL ANN ARBOR, MICHIGAN C1 Westinghouse Elect Co, Sci & Technol Ctr, Pittsburgh, PA 15235 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Dulloo, AR (reprint author), Westinghouse Elect Co, Sci & Technol Ctr, 1310 Beulah Rd, Pittsburgh, PA 15235 USA. NR 3 TC 31 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 11 PY 1999 VL 422 IS 1-3 BP 47 EP 48 DI 10.1016/S0168-9002(98)01060-2 PG 2 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 171MY UT WOS:000078868800011 ER PT J AU Beichl, I Sullivan, F AF Beichl, I Sullivan, F TI Approximating the permanent via importance sampling with application to the dimer covering problem SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID MATRICES AB We estimate the asymptotic growth rate of the number of dimer covers of a cubic lattice, Our estimate, lambda(3) = 0.4466 +/- 0.0006 is consistent with the lower bounds obtained by Hammersley and (later) Schrijver and the more recent improved upper bound obtained by Ciucu. Obtaining this estimate is an important step toward approximating the partition function of the cubic monomer-dimer system. From the partition function, all of the standard thermodynamic quantities can be evaluated. It is well known that computing hs is equivalent to computing the permanent of a certain 0-1 matrix. We describe an extremely efficient Monte Carlo algorithm for approximating the permanent. Previous work on Monte Carlo approaches includes the pioneering results of Jerrum and Sinclair, who use a rapidly mixing random walk. Our method is inspired by results of Soules on convergence of Sinkhorn balancing to obtain a maximum entropy, doubly stochastic matrix. We use the Sinkhorn balanced matrix to generate an importance function that allows us to do direct random sampling, rather than a random walk that converges to a limiting distribution. (C) 1999 Academic Press. C1 NIST, Gaithersburg, MD 20899 USA. IDA, Ctr Comp Sci, Bowie, MD 20715 USA. RP Beichl, I (reprint author), NIST, Gaithersburg, MD 20899 USA. EM isabel@cam.nist.gov; fran@super.org NR 28 TC 22 Z9 22 U1 0 U2 0 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD FEB 10 PY 1999 VL 149 IS 1 BP 128 EP 147 DI 10.1006/jcph.1998.6149 PG 20 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 164NQ UT WOS:000078470800007 ER PT J AU Gay, SC Beale, PD Rainwater, JC AF Gay, SC Beale, PD Rainwater, JC TI Thermodynamic perturbation theory applied to the dipolar heteronuclear dumbbell fluid SO MOLECULAR PHYSICS LA English DT Article ID SIMPLE POLAR FLUIDS; MONTE-CARLO; HARD SPHERES; MOLECULES; SIMULATIONS; EQUILIBRIUM; EQUATION; LIQUIDS AB The perturbation theory of Stell and coworkers as extended by Boublik and Vega is applied to the dipolar heteronuclear dumbbell fluid using the hard heteronuclear dumbbell fluid as a reference system. Monte Carlo simulations in the constant pressure and temperature ensemble have been carried out to determine the accuracy of the theory. The calculated thermodynamic properties are density, internal energy, and chemical potential. The theory shows good agreement with the simulation results over a large range of densities and dipole moments, similar to the findings of Patey and Valleau for dipolar hard spheres. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Gay, SC (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway,838-08, Boulder, CO 80303 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD FEB 10 PY 1999 VL 96 IS 3 BP 301 EP 307 DI 10.1080/002689799165611 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 165JT UT WOS:000078518200002 ER PT J AU Pardo, H Ortiz, WA Araujo-Moreira, FM Suescun, L Toby, B Quagliata, E Negreira, CA Prassides, K Mombru, AW AF Pardo, H Ortiz, WA Araujo-Moreira, FM Suescun, L Toby, B Quagliata, E Negreira, CA Prassides, K Mombru, AW TI A new structure in the REBaCuFeO5+delta series: LaBaCuFeO5+delta. Structure and magnetic properties in the La1-xPrxBaCuFeO5+delta system SO PHYSICA C LA English DT Article DE YBaCuFeO5; neutron diffraction; structure; magnetism ID OXYGEN-DEFICIENT PEROVSKITE; NEUTRON-DIFFRACTION; PHASE-TRANSITION; MOSSBAUER; YBACUFEO5+DELTA; LABA2CU3O7-DELTA; PRBA2CU3O7; CRYSTAL AB The crystal structure of LaBaCuFeO5 + 8 is determined by neutron powder diffraction at 15 K and the structure and magnetic properties of the La1-xPrxBaCuFeO5 + 8 system are studied by AC-susceptibility measurements and RT Fe-57 Mossbauer spectroscopy. The best fit using the Rietveld method is obtained for an orthorhombic model in space group I mmm with unit cell parameters a = 5.5586(8) Angstrom, b = 5.5550(9) Angstrom and c = 7.8155(2) Angstrom. The main feature of this model is a disordered structure where the oxygen atom vacancies play an important role. The magnetic susceptibility in the La1-xPrxBaCuFeO5 + (8) system is studied and T-f, mu(eff) and Theta are determined, Mossbauer spectra provide information relative to the iron electronic state and environment. They support the hypothesis of the key role that the oxygen atom positions play in the magnetic properties of the system by affecting the superexchange interactions in the network. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Republ, Fac Quim, Catedra Fis, Lab Cristalog, Montevideo, Uruguay. Univ Fed Sao Carlos, Dept Fis, BR-13560 Sao Carlos, Brazil. NIST, Div Reactor Radiat, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Republ, Fac Ingn, Lab Acust Ultrasonora, Montevideo, Uruguay. Univ Sussex, Sch Chem Phys & Environm Sci, Brighton BN1 9QJ, E Sussex, England. RP Mombru, AW (reprint author), Univ Republ, Fac Quim, Catedra Fis, Lab Cristalog, POB 1157, Montevideo, Uruguay. RI Prassides, Kosmas/C-9804-2009; Toby, Brian/F-3176-2013; Ortiz, Wilson/K-7379-2012 OI Toby, Brian/0000-0001-8793-8285; NR 25 TC 21 Z9 25 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD FEB 10 PY 1999 VL 313 IS 1-2 BP 105 EP 114 DI 10.1016/S0921-4534(98)00668-6 PG 10 WC Physics, Applied SC Physics GA 170NB UT WOS:000078811100015 ER PT J AU Mackey, EA Demiralp, R Fitzpatrick, KA Porter, BJ Wise, SA Becker, PR Greenberg, RR AF Mackey, EA Demiralp, R Fitzpatrick, KA Porter, BJ Wise, SA Becker, PR Greenberg, RR TI Quality assurance in analysis of cryogenically stored liver tissue specimens from the NIST National Biomonitoring Specimen Bank (NBSB) SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE cryogenic storage; liver tissue; National Biomonitoring Specimen Bank (NBSB); neutron activation analysis (NAA); quality assurance (QA); standard reference material (SRM); trace elements AB Portions of liver tissue specimens originally stored in the National Biomonitoring Specimen Bank (NBSB) and analyzed between 1980 and 1987 were re-analyzed in 1997 using instrumental neutron activation analysis (INAA) for the determination of 17 trace elements. Duplicate portions of each specimen had been stored at two different temperatures. The first was stored in a liquid nitrogen vapor-cooled freezer at -150 degrees C, standard NBSB storage conditions, and the other in an electric freezer maintained at - 80 degrees C. Two portions of seven livers from each storage temperature were re-analyzed for this work. Results showed no changes in trace element content as a function of storage temperature, within the uncertainty of the method used. Results from these analyses agreed with results of initial analyses for most analytes in most sub-samples. Of the exceptions, five were due, in part, to an incorrect basis mass for the initial sub-specimen of one tissue, five with variable Zn results were attributed to difficulties in peak fitting for this element during INAA data processing, and the remaining were isolated differences discussed in this paper. Results of this work indicate that specimen storage and processing protocols are adequate to prevent noticeable contamination of specimens with trace elements, with the exception of Cr. Variability in Cr content was observed for the liver tissues which may have been caused by Cr contamination of the samples by the Teflon mill. Analyses of portions of Standard Reference Material (SRM) 1566a Oyster Tissue (certified in 1989) and SRM 1577a Bovine Liver (certified in 1982) were also included in this study for the purpose of quality control and to assess the stability of these freeze-dried powders that were stored at room temperature. No changes were observed in these materials. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Mackey, EA (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 13 TC 2 Z9 3 U1 2 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 EI 1879-1026 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD FEB 9 PY 1999 VL 226 IS 2-3 BP 165 EP 176 DI 10.1016/S0048-9697(98)00387-8 PG 12 WC Environmental Sciences SC Environmental Sciences & Ecology GA 173YA UT WOS:000079006300007 PM 10085566 ER PT J AU Veasey, DL Funk, DS Sanford, NA Hayden, JS AF Veasey, DL Funk, DS Sanford, NA Hayden, JS TI Arrays of distributed-Bragg-reflector waveguide lasers at 1536 nm in Yb/Er codoped phosphate glass SO APPLIED PHYSICS LETTERS LA English DT Article ID WAVE-GUIDE LASER AB We have demonstrated an array of monolithic, single-frequency-distributed-Bragg-reflector (DBR), waveguide lasers operating near 1536 nm wavelengths. The lasers were fabricated by forming waveguides in Yb/Er-codoped phosphate glass by ion exchange. The slope efficiency for each laser as a function of launched pump power is 26% and the thresholds occur at 50 mW of launched pump power. An output power of 80 mW was achieved with 350 mW of coupled pump power. Each laser exhibits stable operation on a single longitudinal mode and all have linewidths less than 500 kHz. A comb of waveguides with varying effective indices allows the selection of wavelength using a single-period grating. (C) 1999 American Institute of Physics. [S0003-6951(99)01606-X]. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 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 14 TC 65 Z9 67 U1 1 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 8 PY 1999 VL 74 IS 6 BP 789 EP 791 DI 10.1063/1.123368 PG 3 WC Physics, Applied SC Physics GA 163RL UT WOS:000078419200005 ER PT J AU Carlson, JK Palmer, CL Parsons, GR AF Carlson, JK Palmer, CL Parsons, GR TI Oxygen consumption rate and swimming efficiency of the blacknose shark, Carcharhinus acronotus SO COPEIA LA English DT Article ID LARGE WATER TUNNEL; METABOLIC-RATE; PERFORMANCE; LOCOMOTION; DOGFISH; TUNA AB Oxygen consumption rates and swimming efficiency of 10 blacknose sharks (47-87 cm total length and 0.45-3.51 kg weight), Carcharhinus acronotus, were determined using a closed, circular respirometer, Swimming speed ranged from 20-40 cm sec(-1) and averaged 30.8 (+/- 0.48 SE) cm sec(-1). Routine weight specific oxygen consumption rates increased from 278.5 mg 0(2) kg(-1) h(-1) for a 3.5 kg shark to 486 mg 0(2) kg(-1) h(-1) for a 0.8 kg shark. The relationship of swimming speed and weight specific oxygen consumption rate for sharks: 0.45-0.85 kg was described by the equation log V0(2) = 0.007 U + 2.38, r(2) = 0.31, P = 0.006, where U is swimming speed in cm sec(-1). Mean standard metabolic rate, the amount of oxygen consumed at zero activity, was calculated by extrapolating to zero swimming speed and was 239.8 mg 0(2) kg(-1) h(-1), Total cost of transport (cal g(-1) km(-1)), the energy required to travel a given distance at a particular speed, was used as a measure of overall swim efficiency, Highest total cost of transport (1.68 cal g(-1) km(-1)) was at 25 cm sec(-1) and decreased with increasing speed. Swimming efficiency was optimal at speeds of 36-39 cm sec(-1), Results suggest blacknose sharks have higher routine oxygen consumption rates and total cost of transport, but the cost of locomotion was similar to other active, tropical sharks. C1 SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Panama City, FL 32408 USA. Univ Mississippi, Dept Biol, University, MS 38677 USA. RP Carlson, JK (reprint author), SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. EM jcarlson@olemiss.edu; cpalmer@nmfspc.ssp.nmfs.gov; bygrp@olemiss.edu NR 22 TC 23 Z9 24 U1 0 U2 10 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD FEB 5 PY 1999 IS 1 BP 34 EP 39 PG 6 WC Zoology SC Zoology GA 167TY UT WOS:000078650400004 ER PT J AU Eitner, B Kimbrell, C Vetter, R AF Eitner, B Kimbrell, C Vetter, R TI Sebastes moseri (Scorpaeniformes : Scorpaenidae): A new rockfish from the eastern North Pacific SO COPEIA LA English DT Article AB A single specimen of Sebastes collected in 1995 off San Diego, California, has a combination of morphological characters unique among eastern North Pacific rock-fishes. Comparison of partial cytochrome b gene sequences of this specimen and 52 described species of Sebastes (part of an unpublished dataset to elucidate phylogenetic relationships) suggests that the specimen is not a hybrid or morphological variant of these species. A new species, Sebastes moseri (suggested common name "whitespeckled rockfish"), is described. Particularly distinctive are numerous, small white spots covering most of the body (which disappear with preservation), similar to those observed in S. constellatus but without the larger white regions between the dorsal fin and lateral line observed in that species. A preliminary phylogenetic analysis of our DNA sequence data suggests that S. moseri is most closely related to S. rufus. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Eitner, B (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. EM beitner@ucsd.edu NR 10 TC 4 Z9 4 U1 0 U2 0 PU AMER SOC ICHTHYOLOGISTS & HERPETOLOGISTS PI MIAMI PA MAUREEN DONNELLY, SECRETARY FLORIDA INT UNIV BIOLOGICAL SCIENCES, 11200 SW 8TH STREET, MIAMI, FL 33199 USA SN 0045-8511 EI 1938-5110 J9 COPEIA JI Copeia PD FEB 5 PY 1999 IS 1 BP 85 EP 92 DI 10.2307/1447388 PG 8 WC Zoology SC Zoology GA 167TY UT WOS:000078650400010 ER PT J AU Kiselev, SB Friend, DG AF Kiselev, SB Friend, DG TI Revision of a multiparameter equation of state to improve the representation in the critical region: application to water SO FLUID PHASE EQUILIBRIA LA English DT Article DE equation of state; water; critical point ID NONASYMPTOTIC CRITICAL-BEHAVIOR; GLOBAL THERMODYNAMIC BEHAVIOR; CROSSOVER FUNCTIONS; PHASE-BEHAVIOR; FIELD-THEORY; FLUIDS; MODEL AB We have developed a crossover formalism for the thermodynamic surface of pure fluids, which can be applied to any multiparameter equation of state. This procedure has been used to incorporate scaling law behavior into a representation of the thermodynamic properties of water and steam developed by Pruss and Wagner (PW EOS) and adopted recently by the International Association for the Properties of Water and Steam. Our revision to this equation retains most of the functional form and coefficients of the PW EOS, but replaces two of the terms with a crossover representation of scaling law behavior. In order to develop this model, we first developed a new crossover formulation for steam in the critical region, and second, we have incorporated universal crossover functions into the original PW EOS. In the modified form, the PW equation of state reproduces the scaling laws down to dimensionless temperatures tau=10(-7). Far from the critical point the equations practically coincide. (C) 1999 Elsevier Science B.V. All rights reserved. C1 US Dept Commerce, Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Friend, DG (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 41 TC 38 Z9 38 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD FEB 5 PY 1999 VL 155 IS 1 BP 33 EP 55 DI 10.1016/S0378-3812(98)00450-6 PG 23 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 170DT UT WOS:000078791500003 ER PT J AU Travis, JC Kramer, GW Smith, MV Choquette, SJ AF Travis, JC Kramer, GW Smith, MV Choquette, SJ TI Challenges in providing standard reference materials for chemical and pharmaceutical process analysis SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT 3rd Conference on Optical Spectrometry - Applications and Instrumentation into the 21st-Century CY JUN 29-JUL 01, 1998 CL EGHAM, ENGLAND SP Council Radiat Measurement, Ultra Violet Spectrometry Grp DE absorbance; optical filters; reference materials; spectrophotometry; transmittance; UV/visible; wavelength standard AB The NIST Analytical Chemistry Division has supplied transmittance verification and wavelength calibration standard reference materials (SRMs) specialized to the needs of chemical and pharmaceutical spectrophotometric analysis since 1970. Growing demand for UV/visible standards stems from the increasingly routine use of spectrophotometers for pharmaceutical quality control and from the escalation in the documented use of standards for regulatory and voluntary quality control purposes. To meet the demand, NIST is studying ways to accelerate standards production. Projects include studies of the origin of transmittance drift (which necessitates aging during production), investigations of solid UV filters and of sealed liquid standards, and the devleopment of an NIST-traceable reference material (NTRM(TM)) optical filters program to involve the private sector. Recently, we have revised the optical specifications of our solid filter standards to meet the requirements of reversed-geometry (post-dispersion) instruments. In the near-infrared, spectrochemical process control applications mandate the need for wavelength standards to support the stability and instrument-to-instrument transfer capability of multivariate analytical calibration models. We are presently producing one such standard and are investigating others. Finally, we are studying algorithms for locating peaks in wavelength standards to find a consistent means for making wavelength assignments from the UV through the mid-infrared. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Travis, JC (reprint author), NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. EM john.travis@nist.gov NR 17 TC 4 Z9 4 U1 0 U2 0 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 FEB 2 PY 1999 VL 380 IS 2-3 BP 115 EP 126 DI 10.1016/S0003-2670(98)00475-9 PG 12 WC Chemistry, Analytical SC Chemistry GA 164QK UT WOS:000078474900002 ER PT J AU Early, EA O'Brian, TR AF Early, EA O'Brian, TR TI NIST transmission density instrument SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT 3rd Conference on Optical Spectrometry - Applications and Instrumentation into the 21st-Century CY JUN 29-JUL 01, 1998 CL EGHAM, ENGLAND SP Council Radiat Measurement, Ultra Violet Spectrometry Grp DE densitometer; diffuse transmission; standard reference materials; transmission density AB The Optical Technology Division of NIST has developed a new instrument for measuring ISO standard visual diffuse transmission densities using the diffuse influx mode. This instrument is used to calibrate both X-ray and photographic film step tablet Standard Reference Materials. The design, characterization, and operation of the instrument are detailed. The instrument was fully characterized both to verify compliance with the applicable international standards and to determine the combined uncertainty in transmission density associated with the calibrations. Results from comparisons with other laboratories are also presented. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Early, EA (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 10 TC 2 Z9 2 U1 0 U2 0 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 FEB 2 PY 1999 VL 380 IS 2-3 BP 143 EP 153 DI 10.1016/S0003-2670(98)00686-2 PG 11 WC Chemistry, Analytical SC Chemistry GA 164QK UT WOS:000078474900004 ER PT J AU Hanssen, LM Kaplan, S AF Hanssen, LM Kaplan, S TI Infrared diffuse reflectance instrumentation and standards at NIST SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT 3rd Conference on Optical Spectrometry - Applications and Instrumentation into the 21st-Century CY JUN 29-JUL 01, 1998 CL EGHAM, ENGLAND SP Council Radiat Measurement, Ultra Violet Spectrometry Grp DE infrared; spectral reflectance; directional-hemispherical reflectance; diffuse reflectance; integrating sphere AB A spectrophotometer system for spectral characterization of materials in the infrared has been built around a bench-top Fourier transform instrument. Its capabilities include the measurement of directional-hemispherical reflectance from 1 to 18 mu m. The spectral reflectance measurement is performed with an integrating sphere with an incidence angle of 8 degrees. Both relative and absolute measurements can be made. Several methods can be used to determine the absolute value of the directional-hemispherical reflectance of samples. The primary method used is independent of the integrating sphere theory and the requisite assumptions associated with its use. The calibration of a standard reference material (SRM) is described. This SRM has a reflectance value near 0.9 over the complete calibration range 2-18 mu m. As part of the calibration procedure the spatial uniformity of the sphere throughput and the bi-directional reflectance distribution function (BRDF) of the SRM material are evaluated. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Hanssen, LM (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. EM hanssen@nist.gov NR 15 TC 21 Z9 22 U1 0 U2 4 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 FEB 2 PY 1999 VL 380 IS 2-3 BP 289 EP 302 DI 10.1016/S0003-2670(98)00669-2 PG 14 WC Chemistry, Analytical SC Chemistry GA 164QK UT WOS:000078474900016 ER PT J AU Kaplan, SG Hanssen, LM AF Kaplan, SG Hanssen, LM TI Infrared regular reflectance and transmittance instrumentation and standards at NIST SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT 3rd Conference on Optical Spectrometry - Applications and Instrumentation into the 21st-Century CY JUN 29-JUL 01, 1998 CL EGHAM, ENGLAND SP Council Radiat Measurement, Ultra Violet Spectrometry Grp DE infrared regular reflectance; transmittance; FT-IR measurements; beam geometry ID FT-IR; ACCURACY; FILTERS AB Instrumentation is described that has been constructed at the National Institute of Standards and Technology (NIST) for the measurement of regular reflectance and transmittance over the 2-25 mu m wavelength region. This includes both specialized accessories used with Fourier-transform infrared (FT-IR) spectrometers and laser-based systems for high optical density transmittance measurements. The FT-IR systems have been used to develop standard reference materials for IR regular transmittance. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Kaplan, SG (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. EM simon.kaplan@nist.gov NR 19 TC 4 Z9 4 U1 0 U2 1 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 FEB 2 PY 1999 VL 380 IS 2-3 BP 303 EP 310 DI 10.1016/S0003-2670(98)00670-9 PG 8 WC Chemistry, Analytical SC Chemistry GA 164QK UT WOS:000078474900017 ER PT J AU Migdall, A Dauler, E Muller, A Sergienko, A AF Migdall, A Dauler, E Muller, A Sergienko, A TI Tests of an omnipresent standard for absolute spectral radiance measurements SO ANALYTICA CHIMICA ACTA LA English DT Article; Proceedings Paper CT 3rd Conference on Optical Spectrometry - Applications and Instrumentation into the 21st-Century CY JUN 29-JUL 01, 1998 CL EGHAM, ENGLAND SP Council Radiat Measurement, Ultra Violet Spectrometry Grp DE spectral radiance; standard AB Correlated pairs of photons can be used to access what is effectively an omnipresent absolute standard of spectral radiance. The process of spontaneous parametric downconversion, in which pump photons are converted into pairs of photons, can be thought of as being stimulated by an omnipresent and omnidirectional one photon per mode vacuum background. This background has units of spectral radiance and can be expressed in terms of fundamental constants. An unknown radiance can be determined by comparison to this background radiance. The comparison is made by adding the unknown radiance into downconversion process so as to stimulate the downconversion process over that level produced by the vacuum background only. This is done by inputting the unknown radiance into the system so as to overlap spatially and spectrally a portion of the output light. The process is monitored, not by observing the input light beam, but by observing only the light correlated to that unknown radiance. (This makes possible an additional advantage of this measurement technique; it allows IR radiance to be measured by monitoring a visible beam.) The ratio of the increase in the correlated signal is the absolute spectral radiance of the unknown source expressed in units of photons per mode. Initial studies of feasibility and accuracy have been performed. IR radiance has been measured to wavelengths of 5 mu m with better than 3% uncertainty. We present the status of work to further improve the uncertainty of this method. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. Boston Univ, Dept Elect & Comp Engn, Boston, MA 02215 USA. RP Migdall, A (reprint author), NIST, Opt Technol Div, 221-B208, Gaithersburg, MD 20899 USA. NR 10 TC 3 Z9 3 U1 0 U2 0 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 FEB 2 PY 1999 VL 380 IS 2-3 BP 311 EP 316 DI 10.1016/S0003-2670(98)00685-0 PG 6 WC Chemistry, Analytical SC Chemistry GA 164QK UT WOS:000078474900018 ER PT J AU Melov, S Coskun, P Patel, M Tuinstra, R Cottrell, B Jun, AS Zastawny, TH Dizdaroglu, M Goodman, SI Huang, TT Miziorko, H Epstein, CJ Wallace, DC AF Melov, S Coskun, P Patel, M Tuinstra, R Cottrell, B Jun, AS Zastawny, TH Dizdaroglu, M Goodman, SI Huang, TT Miziorko, H Epstein, CJ Wallace, DC TI Mitochondrial disease in superoxide dismutase 2 mutant mice SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID IRON-RESPONSIVE ELEMENTS; 3-METHYLGLUTACONIC ACIDURIA; OXIDATIVE STRESS; DILATED CARDIOMYOPATHY; HEART-MITOCHONDRIA; DEFICIENT MICE; 3-HYDROXY-3-METHYLGLUTARYL-COA LYASE; HYPERTROPHIC CARDIOMYOPATHY; TRANSLATIONAL REGULATION; MAMMALIAN-CELLS AB Oxidative stress has been implicated in many diseases. The chief source of reactive oxygen species within the cell is the mitochondrion. We have characterized a variety of the biochemical and metabolic effects of inactivation of the mouse gene for the mitochondrial superoxide dismutase (CD1-Sod2(tm1Cje)). The Sod2 mutant mice exhibit a tissue-specific inhibition of the respiratory chain enzymes NADH-dehydrogenase (complex I) and succinate dehydrogenase (complex II), inactivation of the tricarboxylic acid cycle enzyme aconitase, development of a urine organic aciduria in conjunction with a partial defect in 3-hydroxy-3 -methylglutaryl-CoA lyase, and accumulation of oxidative DNA damage. These results indicate that the increase in mitochondrial reactive oxygen species can result in biochemical aberrations with features reminiscent of mitochondrial myopathy, Friedreich ataxia, and 3-hydroxy-3-methylglutaryl-CoA lyase deficiency. C1 Emory Univ, Ctr Mol Med, Atlanta, GA 30322 USA. Natl Jewish Med & Res Ctr, Denver, CO 80206 USA. Med Coll Wisconsin, Dept Biochem, Milwaukee, WI 53226 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Colorado, Sch Med, Dept Pediat, Denver, CO 80262 USA. Univ Calif San Francisco, Div Med Genet, San Francisco, CA 94143 USA. RP Wallace, DC (reprint author), Emory Univ, Ctr Mol Med, 1462 Clifton Rd, Atlanta, GA 30322 USA. FU NHLBI NIH HHS [HL45572]; NIA NIH HHS [AG13154, R01 AG013154]; NICHD NIH HHS [P30 HD004024]; NIDDK NIH HHS [R01 DK021491, R37 DK021491]; NINDS NIH HHS [NS21328, R01 NS021328] NR 72 TC 404 Z9 414 U1 0 U2 10 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD FEB 2 PY 1999 VL 96 IS 3 BP 846 EP 851 DI 10.1073/pnas.96.3.846 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 164VK UT WOS:000078484100011 PM 9927656 ER PT J AU Fitting, DW Dube, WP Siewert, TA AF Fitting, DW Dube, WP Siewert, TA TI High-energy X-rays monitor solidification SO ADVANCED MATERIALS & PROCESSES LA English DT Article C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Fitting, DW (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Dube, William/I-1658-2013 OI Dube, William/0000-0003-1286-4087 NR 0 TC 0 Z9 0 U1 0 U2 2 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0026-0665 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD FEB PY 1999 VL 155 IS 2 BP 43 EP 45 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 164FR UT WOS:000078453000007 ER PT J AU Hall, B Claiborn, C Baldocchi, D AF Hall, B Claiborn, C Baldocchi, D TI Measurement and modeling of the dry deposition of peroxides SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE deposition velocity; surface resistance; eddy diffusivity; hydrogen peroxide; organic peroxide ID REACTIVE TRACE GASES; FLUX-GRADIENT RELATIONSHIPS; RED SPRUCE NEEDLES; WATER-VAPOR; HYDROGEN-PEROXIDE; DECIDUOUS FOREST; PLANT CANOPIES; BOUNDARY-LAYER; HEAT; TRANSPORT AB Measurements of the dry deposition velocity (V-d) of hydrogen peroxide (H2O2) and total organic peroxides (ROOH) were made during four experiments at three forested sites. Details and uncertainties associated with the measurement of peroxide fluxes by the flux-gradient method are discussed. The results are compared to those predicted using a bulk-resistance model of the type commonly used in regional photochemical models. Good agreement between the H2O2 V-d measurements and a bulk resistance model is obtained when the model contains a zero surface resistance (R-c) and a common form for the laminar leaf-layer resistance (R-b) based on Schmidt and Prandtl numbers. In this case, a near-zero (<5 sm(-1))surface resistance is confirmed for H2O2 within experimental uncertainties. Surface resistances for ROOH were determined to be about 10-15 sm(-1) over a coniferous forest and 20-40 sm(-1) over a deciduous forest. Higher uncertainties for ROOH prevent a detailed analysis of the differences in R-c among forest types. However, the ratio of deposition velocities (ROOH/H2O2), computed from normalized concentration gradients, ranged from 0.28 to 0.61 (geometric mean) at the three sites. Differences in molecular diffusivities between H2O2 and ROOH can only account for an estimated 16% difference in V-d. Thus, the major constituent of ROOH must also be less soluble and/or less reactive than H2O2, which is consistent with the characteristics of methylhydroperoxide (MHP). (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Washington State Univ, Dept Civil & Environm Engn, Pullman, WA 99164 USA. Natl Ocean & Atmospher Adm, Oak Ridge, TN USA. RP Hall, B (reprint author), CSIRO, Cooperat Res Ctr So Hemisphere Meteorol, POB 218, Sydney, NSW 2070, Australia. RI Baldocchi, Dennis/A-1625-2009 OI Baldocchi, Dennis/0000-0003-3496-4919 NR 45 TC 16 Z9 17 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1999 VL 33 IS 4 BP 577 EP 589 DI 10.1016/S1352-2310(98)00271-4 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 160KN UT WOS:000078229700006 ER PT J AU van Aardenne, JA Carmichael, GR Levy, H Streets, D Hordijk, L AF van Aardenne, JA Carmichael, GR Levy, H Streets, D Hordijk, L TI Anthropogenic NOx emissions in Asia in the period 1990-2020 SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE NOx emissions; fossil fuels; Asia energy use; transportation; power sector ID DIOXIDE EMISSIONS; FUEL COMBUSTION; POLLUTION; WORLD; CHINA; SO2 AB Nitrogen oxides emissions in Asia during the period 1990-2020 due to anthropogenic activity are presented. These estimates are based on the RAINS-ASIA methodology (Foell et al., 1995, Acid Rain and Emission Reduction in Asia, World Bank), which includes a dynamic model for energy forecasts, and information on 6 energy sectors and 9 fuel types. The energy forecasts are combined with process emission factors to yield NO, emission estimates at the country level, the regional level, and on a 1 degree by 1 degree grid. In 1990 the total NO, emissions are estimated to be similar to 19 Tg NO2, with China (43 %), India (18 %) and Japan (13 %) accounting for 75 % of the total. Emissions by fuel are dominated by burning of hard coal and emissions by economic activity are dominated by the power. transport, and industrial sectors. These new estimates of NO, emissions are compared with those published by Hameed and Dignon (1988, Atmospheric Environment 22, 441-449) and Akimoto and Narita (1994, Atmospheric Environment 28, 213-225). Future emissions under a no- further-control scenario are also presented. During the period 1990-2020 the NOx emissions increase by 350%, to similar to 86 Tg NO2. The increase in NOx emissions by sector and end-use varies between countries, but in all countries this increase is strongest in the power and transport sectors. These results highlight the dynamic nature of energy use in Asia, and the need to take the rapid growth in NO, emissions in Asia into account in studies of air pollution and atmospheric chemistry. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Agr Univ Wageningen, Wageningen Ctr Environm & Climate Studies, NL-6700 HB Wageningen, Netherlands. Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA USA. Univ Iowa, Dept Chem & Biochem Engn, Iowa City, IA USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP van Aardenne, JA (reprint author), Agr Univ Wageningen, Wageningen Ctr Environm & Climate Studies, POB 9101, NL-6700 HB Wageningen, Netherlands. OI Streets, David/0000-0002-0223-1350 NR 30 TC 160 Z9 164 U1 3 U2 36 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 1999 VL 33 IS 4 BP 633 EP 646 DI 10.1016/S1352-2310(98)00110-1 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 160KN UT WOS:000078229700012 ER PT J AU Kasianowicz, JJ Burden, DL Han, LC Cheley, S Bayley, H AF Kasianowicz, JJ Burden, DL Han, LC Cheley, S Bayley, H TI Genetically engineered metal ion binding sites on the outside of a channel's transmembrane beta-barrel SO BIOPHYSICAL JOURNAL LA English DT Article ID AUREUS ALPHA-TOXIN; PLANAR LIPID BILAYER; STAPHYLOCOCCUS-AUREUS; PROTON-TRANSFER; PORE; PROTEIN; HEMOLYSIN; MEMBRANES; MUTAGENESIS; BIOSENSORS AB We are exploring the ability of genetically engineered versions of the Staphylococcus aureus alpha-hemolysin (alpha HL) ion channel to serve as rationally designed sensor components for analytes including divalent cations. We show here that neither the hemolytic activity nor the single channel current of wild-type alpha HL was affected by [Zn(ll)] less than or equal to 1 mM. Binding sites for the divalent cations were formed by altering the number and location of coordinating side chains, e.g., histidines and aspartic acids, between positions 126 and 134, inclusive. Several mutant alpha HLs exhibited Zn(ll)-induced current noise that varied with Zn(ll) concentration. At a fixed divalent cation concentration, the current fluctuation kinetics depended on the analyte type, e.g., Zn(il), Cu(ll), Ni(ll), and Co(ll). We also show that the ability of Zn(ll) to change the mutant channel current suggests that the pore's topology is beta-sheet and that position 130 is near the turn at the trans mouth. Both conclusions are consistent with the crystal structure of WT-alpha HL oligomerized in detergent. Our results, in the context of the channel's crystal structure, suggest that conductance blockades were caused by Zn(ll) binding to the outside surface of the pore. Thus, analyte-induced current blockades alone might not establish whether an analyte binding site is inside a pore. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Indiana Univ, Dept Chem, Bloomington, IN 47405 USA. Texas A&M Univ, Hlth Sci Ctr, Dept Med Biochem & Genet, College Stn, TX 77843 USA. RP Kasianowicz, JJ (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. EM john.kasianowicz@nist.gov NR 41 TC 61 Z9 63 U1 0 U2 7 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD FEB PY 1999 VL 76 IS 2 BP 837 EP 845 DI 10.1016/S0006-3495(99)77247-4 PG 9 WC Biophysics SC Biophysics GA 162VZ UT WOS:000078368800021 PM 9929485 ER PT J AU Weetall, HH AF Weetall, HH TI Chemical sensors and biosensors, update, what, where, when and how SO BIOSENSORS & BIOELECTRONICS LA English DT Editorial Material AB Chemical and biosensor technologies can play an important role in the development and improvement of public health by finding application in al eas where rapid detection, high sensitivity and specificity are important. The chemical industry is looking for realtime methods for monitoring, quantitating and differential analysis of gas mixtures from chemical processes and products. The oil and gas industries need sensors for monitoring and quantitating volatile organic compounds. The pulp and paper industry requires sensors for monitoring bleaching processes as well as toxic compounds used and produced in their processing. In addition, if available at an acceptable cost, CO sensors could find their way into homes and offices throughout the U.S. Commercialization of chemical sensor and biosensor technologies has continued to lag behind the research by several years. The reasons are many. There have always been cost considerations, this includes the poor integration of many biosensors and chemical sensors into easy to use systems. Additional concerns are stability and sensitivity issues, quality assurance and competitive technologies. These issues have been identified not only as concerns, but as the major risks associated with development of chemical sensor and biosensor systems. The advent of MEMS technology and the microprocessor has made some inroads into the sensor industry. However, even today commercialization of sensors for the chemical, bioprocessing and clinical diagnostic industries are limited. A clear requirement for the successful commercialization of chemical sensors and biosensors is an application need, either established or successfully predicted. In addition the technology must offer advantages over existing technologies. Issues not always addressed before the sensor reaches the development stage are market size and justification, development cost, and ease of manufacture. From a technical point of view, many sensors have not been commercially developed because the underlying basic science is not available. Development cycles are long and necessary materials not well understood. There are still major barriers to the commercialization of sensors for the chemical, bioprocessing, and clinical diagnostic industries. Many of these barriers are technical, technology transfer, funding in early stages of development, and establishment of effective interdisciplinary partnerships. In terms of funding in the U.S., the resources available from government agencies for initial stages of high risk technology research and development are limited to SBIR's and STTR's. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 NIST, US Dept Commerce, Gaithersburg, MD 20899 USA. RP Weetall, HH (reprint author), NIST, US Dept Commerce, Gaithersburg, MD 20899 USA. NR 0 TC 37 Z9 37 U1 4 U2 14 PU ELSEVIER ADVANCED TECHNOLOGY PI OXFORD PA OXFORD FULFILLMENT CENTRE THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0956-5663 J9 BIOSENS BIOELECTRON JI Biosens. Bioelectron. PD FEB 1 PY 1999 VL 14 IS 2 BP 237 EP 242 PG 6 WC Biophysics; Biotechnology & Applied Microbiology; Chemistry, Analytical; Electrochemistry; Nanoscience & Nanotechnology SC Biophysics; Biotechnology & Applied Microbiology; Chemistry; Electrochemistry; Science & Technology - Other Topics GA 168UA UT WOS:000078710000015 ER PT J AU Petersen, WA Carey, LD Rutledge, SA Knievel, JC Doesken, NJ Johnson, RH McKee, TB Vonder Haar, T Weaver, JF AF Petersen, WA Carey, LD Rutledge, SA Knievel, JC Doesken, NJ Johnson, RH McKee, TB Vonder Haar, T Weaver, JF TI Mesoscale and radar observations of the Fort Collins flash flood of 28 July 1997 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID PRECIPITATION DEVELOPMENT; FLORIDA THUNDERSTORM; NORTHEAST COLORADO; CONVECTIVE CELLS; BIG THOMPSON; STORM; ELECTRIFICATION; CUMULONIMBUS; RAINFALL; REFLECTIVITY AB On the evening of 28 July 1997 the city of Fort Collins, Colorado, experienced a devastating flash flood that caused five fatalities and over 200 million dollars in damage. Maximum accumulations of rainfall in the western part of the city exceeded 10 in. in a 6-h period. This study presents a multiscale meteorological overview of the event utilizing a wide variety of instrument platforms and data including rain gauge, CSU-CHILL multiparameter radar, Next Generation Radar, National Lightning Detection Network, surface and Aircraft Communication Addressing and Reporting System observations, satellite observations, and synoptic analyses. Many of the meteorological features associated with the Fort Collins flash flood typify those of similar events in the western United States. Prominent features in the Fort Collins case included the presence of a 500-hPa ridge axis over northeastern Colorado; a weak shortwave trough on the western side of the ridge; postfrontal easterly upslope flow at low levels; weak to moderate southwesterly flow aloft; a deep, moist warm layer in the sounding; and the occurrence of a quasi-stationary rainfall system. In contrast to previous events such as the Rapid City or Big Thompson floods, the thermodynamic environment of the Fort Collins storm exhibited only modest instability, consistent with low lightning flash rates and an absence of hail and other severe storm signatures. Radar, rain gauge, and lightning observations provided a detailed view of the cloud and precipitation morphology. Polarimetric radar observations suggest that a coupling between warm-rain collision coalescence processes and ice processes played an important role in the rainfall production. Dual-Doppler radar and mesoscale wind analyses revealed that the low-level flow field associated with a bow echo located 60 km to the southeast of Fort Collins may have been responsible for a brief easterly acceleration in the low-level winds during the last 1.5 h of the event. The enhanced flow interacted with both topography and the convection located over Fort Collins, resulting in a quasi-stationary convective system and the heaviest rainfall of the evening. C1 Colorado State Univ, Dept Atmospher Sci, Colorado Climate Ctr, Ft Collins, CO 80523 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, RAMM Branch, NOAA,NESDIS, Ft Collins, CO 80523 USA. RP Petersen, WA (reprint author), Colorado State Univ, Dept Atmospher Sci, Colorado Climate Ctr, Ft Collins, CO 80523 USA. RI Vonder Haar, Thomas/F-2048-2011 NR 65 TC 106 Z9 109 U1 2 U2 8 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 FEB PY 1999 VL 80 IS 2 BP 191 EP 216 DI 10.1175/1520-0477(1999)080<0191:MAROOT>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 178HU UT WOS:000079260900002 ER PT J AU Barnston, AG Glantz, MH He, YX AF Barnston, AG Glantz, MH He, YX TI Predictive skill of statistical and dynamical climate models in SST forecasts during the 1997-98 El Nino episode and the 1998 La Nina onset SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SEA-SURFACE TEMPERATURE; NATIONAL-METEOROLOGICAL-CENTER; CANONICAL CORRELATION-ANALYSIS; OSCILLATION PATTERN-ANALYSIS; ENSO-RELATED PREDICTABILITY; TROPICAL PACIFIC-OCEAN; GLOBAL SPECTRAL MODEL; SOUTHERN OSCILLATION; EQUATORIAL PACIFIC; WIND STRESS AB Critical reviews of forecasts of ENSO conditions, based on a set of 15 dynamical and statistical models, are given for the 1997-98 El Nino event and the initial stages of the 1998-99 La Nina. While many of the models forecasted some degree of warming one to two seasons prior to the onset of the El Nino in boreal spring of 1997, none predicted its strength until the event was already becoming very strong in late spring. Neither the dynamical nor the statistical models, as groups, performed significantly better than the other during this episode. The best performing statistical models and dynamical models forecast SST anomalies of about +1 degrees C (vs 2.5 degrees-3 degrees observed) in the Nino 3.4 region prior to any observed positive anomalies. The most comprehensive dynamical models performed better than the simple dynamical models. Once the El Nino had developed in mid-1997, a larger set of models was able to forecast its peak in late 1997 and dissipation and reversal to cold conditions in late spring/early summer 1998. Overall, however, skill for these recent two years does not appear greater than that found over an earlier (1982-93) period. In both cases, median model correlation skill averaged over lead times of one to three seasons is near or just above 0.6. Because ENSO extremes usually develop in boreal spring or early summer and persist through the following winter, forecasting impact tendencies in extratropical North America for winter (when impacts are most pronounced) at 5 months of lead time is not difficult, requiring only good observations of the summer ENSO state and knowledge of the winter teleconnections. Because of the strength of the 1997-98 El Nino acid the consequent skill of 5-month lead forecasts of U.S. winter 1997-98 impacts, the success of these forecasts was noticed to an unprecedented extent by the general public. However, forecasting impacts in austral winter that occur simultaneously with the initial appearance of an ENSO extreme (e.g., in Chile, Uruguay, Kiribati, Ecuador, and Pent) require forecasting the boreal spring/summer onset of ENSO events themselves at several months of lead time. This latter task is formidable, as evidenced by the fact that formal announcements of an El Nino did not occur until May, leaving little time for users in the above regions to prepare. Verbal summaries of ENSO forecasts issued to users worldwide during the 1997-98 El Nino event contained ambiguities. To address the needs for forecasts to be expressed verbally for nontechnical users and also to be precise enough for meaningful utility and verification, a simple numerically based verbal classification system for describing ENSO-related forecasts is presented. C1 NCEP, NWS, NOAA, Climate Predict Ctr, Camp Springs, MD 20746 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Barnston, AG (reprint author), NCEP, NWS, NOAA, Climate Predict Ctr, W-NMC 51,Rm 604,5200 Auth Rd,World Weather Bldg, Camp Springs, MD 20746 USA. NR 74 TC 196 Z9 199 U1 2 U2 11 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 FEB PY 1999 VL 80 IS 2 BP 217 EP 243 DI 10.1175/1520-0477(1999)080<0217:PSOSAD>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 178HU UT WOS:000079260900003 ER PT J AU Westwater, ER Han, Y Snider, JB Churnside, JH Shaw, JA Falls, MJ Long, CN Ackerman, TP Gage, KS Ecklund, W Riddle, A AF Westwater, ER Han, Y Snider, JB Churnside, JH Shaw, JA Falls, MJ Long, CN Ackerman, TP Gage, KS Ecklund, W Riddle, A TI Ground-based remote sensor observations during PROBE in the tropical western Pacific SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID ATMOSPHERE RESPONSE EXPERIMENT; WATER-VAPOR; TOGA-COARE; LIQUID; RATES; CLOUD AB From 6 January to 28 February 1993, the second phase of the Pilot Radiation Observation Experiment (PROBE) was conducted in Kavieng, Papua New Guinea. Routine data taken during PROBE included radiosondes released every 6 h and 915-MHz Wind Profiler-Radio Acoustic Sounding System (RASS) observations of winds and temperatures. in addition, a dual-channel Microwave Water Substance Radiometer (MWSR) at 23.87 and 31.65 GHz and a Fourier Transform Infrared Radiometer (FTIR) were operated. The FTIR operated between 500 and 2000 cm(-1) and measured some of the first high spectral resolution (1 cm(-1)) radiation data taken in the Tropics. The microwave radiometer provided continuous measurements within 30-s resolution of precipitable water vapor (PWV) and integrated cloud liquid, while the RASS measured virtual temperature profiles every 30 min. In addition, occasional lidar soundings of cloud-base heights were available. The MWSR and FTIR data taken during PROBE were compared with radiosonde data. Significant differences were noted between the MWSR and the radiosonde observations of PWV. The probability distribution of cloud liquid water was derived and is consistent with a lognormal distribution. During conditions that the MWSR did not indicate the presence of cloud liquid water, broadband long- and shortwave irradiance data were used to identify the presence of cirrus clouds or to confirm the presence of clear conditions. Comparisons are presented between measured and calculated radiance during clear conditions, using radiosonde data as input to a line-by-line Radiative Transfer Model. A case study is given of a drying event in which the PWV dropped from about 5.5 cm to a low of 3.8 cm during a 24-h period. The observations during the drying event are interpreted using PWV images obtained from data from the Defense Meteorological Satellite Program/Special Sensor Microwave/Imager and of horizontal flow measured by the wind profiler. The broadband irradiance data and the RASS soundings were also examined during the drying event. C1 Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Air Resources Lab, Boulder, CO 80303 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. RP Westwater, ER (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, 325 Broadway,MS R-E-ETI, Boulder, CO 80303 USA. RI Han, Yong/F-5590-2010; Churnside, James/H-4873-2013 OI Han, Yong/0000-0002-0183-7270; NR 30 TC 10 Z9 10 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 FEB PY 1999 VL 80 IS 2 BP 257 EP 270 DI 10.1175/1520-0477(1999)080<0257:GBRSOD>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 178HU UT WOS:000079260900005 ER PT J AU Witting, DA Able, KW Fahay, MP AF Witting, DA Able, KW Fahay, MP TI Larval fishes of a Middle Atlantic Bight estuary: assemblage structure and temporal stability SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID NORTH-CAROLINA ESTUARY; EARLY-LIFE-HISTORY; RECRUITMENT; DYNAMICS; BAY AB We collected weekly, quantitative ichthyoplankton samples over 6 years (1989-1994, 1309 samples) to identify temporal scales of variability in the abundance and occurrence of larval fish assemblages near Little Egg inlet in southern New Jersey, U.S.A. We collected species that spawn in the estuary (30%), both the estuary and continental shelf (35%), continental shelf (25%), and the Sargasso Sea (10%). The following analyses suggest an annually repeated seasonal progression of species assemblages: (i) the rank abundance of the 20 dominant species did not change significantly from year to year, (ii) variation in the density of the dominant species was primarily explained by intraannual rather than interannual variation, and (iii) multivariate analysis of the assemblage matrix identified five seasonal assemblages that occurred during all six years. We found that the timing and duration of each of these seasonal groups were correlated with two characteristics of the annual temperature cycle,magnitude (higher or lower temperature) and trajectory (increasing vs decreasing temperature). We suggest that the repeated occurrence of larval fish assemblages in temperate estuaries along the U.S. coast may, in part, be driven by local environmental processes. C1 NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, Sandy Hooks, NJ 07732 USA. Rutgers State Univ, Inst Marine & Coastal Sci, Marine Field Stn, Tuckerton, NJ 08087 USA. RP Witting, DA (reprint author), NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, 74 Magruder Rd, Sandy Hooks, NJ 07732 USA. EM david.witting@noaa.gov NR 35 TC 50 Z9 51 U1 1 U2 3 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 FEB PY 1999 VL 56 IS 2 BP 222 EP 230 DI 10.1139/cjfas-56-2-222 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 185VN UT WOS:000079691800007 ER PT J AU Holland, DS Sutinen, JG AF Holland, DS Sutinen, JG TI An empirical model of fleet dynamics in New England trawl fisheries SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID MOVEMENT; CATCH AB Regulations and changes in market and environmental conditions that change the profitability of one fishery or area will result in a redistribution of fishing effort among alternative fisheries or areas. The magnitude of this effort displacement will depend on the relative profitability of the alternatives for the individual fishers affected. When fishing areas and fishers are heterogeneous, simple aggregate effort models such as those based on ideal free distribution theory may provide inaccurate predictions. We present an empirical model of individual vessel fishery and location choice based on trip data for a group of over 400 large trawlers fishing in New England. The model uses lagged average revenue rates for different alternatives and the individual vessel's past behavior to predict choice of species group and fishing location on a trip-by-trip basis. This model is used to predict aggregate effort levels in different fisheries and areas over time. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Univ Rhode Isl, Dept Environm & Nat Resource Econ, Kingston, RI 02881 USA. RP Holland, DS (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. OI Holland, Daniel/0000-0002-4493-859X NR 26 TC 93 Z9 93 U1 1 U2 10 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 FEB PY 1999 VL 56 IS 2 BP 253 EP 264 DI 10.1139/cjfas-56-2-253 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 185VN UT WOS:000079691800010 ER EF